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TURIN 2024

1st Joint Meeting of EHRS-HRSE

51st Meeting of the EHRS | 1st Meeting of the HRSE

23/25 May 2024
Turin, Italy

Local Organizing Committee
Arianna Carolina Rosa (Torino, IT); Katerina Tiligada (Athens, EL);
Ilona Obara (Newcastle, UK); Elisa Benetti (Torino, IT); Valentina Boscaro (Torino, IT);
Margherita Gallicchio (Torino, IT); Simona Spampinato (Torino, IT)
Scientific Committee
Pierre Chatelain (BE); Madeleine Ennis (UK); Bernhard Gibbs (DE);Rob Leurs (NL); Detlef Neumann (DE); Ilona Obara (UK); Arianna Carolina Rosa (IT);
Bassem Sadek (UAE); Holger Stark (DE); Satoshi Tanaka (JP); Katerina Tiligada (EL)PATRONAGE

SPONSORWELCOME MESSAGE
It is our great pleasure to welcome you to the 1st Joint meeting of the European Histamine Research Society(EHRS) and the Histamine Research Society Europe (HRSE) May 23-25, 2024 in Turin. This meeting represents
a milestone for these two histamine research society: it is the 51th Meeting of the EHRS, and the 1st Meetingof the just born HRSE. Following the footsteps of the 50 preceding EHRS conferences the meeting will serve
as a forum for the worldwide exchange of novel research results and ideas in the field of histamine and will
provide an excellent opportunity for establishing research cooperation between leading international scientists
from academia. The wide-ranged topics will be presented in 3 lectures including the Opening and GB West
Lecture, 25 oral communications and 16 flash presentation (definitively replacing posters) and a round tableon pharmacovigilance will offer the opportunity to contextualize the results from basic discovery into theirclinical applications in function of the risk-benefit ratio. A session dedicated to the memory of Professor Pier
Francesco Mannaioni will be held. Young Investigator Awards and best flash presentations competition will
also take place.
Host this special meeting is a great honor for us, being the first time for Histamine Research delegates to meetin Turin. The city is a unique location at the base of the Alps in the northwestern corner of Italy. It was the first
capital of Italy (1861 – 1865). The venue of the meeting, the Accademia di Medicina di Torino, is an example on
how Turin has always represented a starting point for innovation in various sectors, including medical sciences.
Indeed, in over 600 years of history, Turin's University is proud of its achievements, including the four Nobel
Prize in Physiology or Medicine awarded to Camillo Golgi, Salvador Luria, Renato Dulbecco, and Rita Levi
Montalcini.
Beside the science, we hope you will enjoy the charm of Turin in your free time. There are plenty of things to
do in Turin. The city is well known for its baroque architecture and stately art-nouveau cafes. The EgyptianMuseum is one of the biggest tourist attractions in Turin and showcases the largest collection of Egyptian
artifacts outside of Cairo. The Mole Antonelliana is an incredible building, visible from all over Turin it has
become the landmark of the city. It was initially designed as a synagogue but was later updated as a monument
to national unity. You can take the lift up to the 85m platform for views of the city. Just next to it, you’ll findthe National Cinema Museum. If you’re a petrol-head, definitely find time to visit Turin’s famous automobile
museum. It has a collection of around 200 cars from 80 different car brands! But do not forget the several Royal
residences, From Palazzo Reale to Venaria Reale, and much more.
Please also take time to taste our food: you can taste incredible food and drink including truffles, delicious
artisan cheeses, different varieties of rice, Piedmontese hazelnuts, and of course Barolo! Not to forgetchocolate: Turin is, with the iconic Gianduiotto, Italy's chocolate capital. Since 2003, Turin organizes the muchloved festival, CioccolaTò. Do not also forget that the legendary Nutella was created in Piedmont by Pietro
Ferrero in 1946. Finally for a real taste of Turin, do not forget to taste Bicerin, a combination of espresso,
chocolate, and cream/whole milk.
We warmly welcome you to the 1st Joint meeting of the EHRS and HRSE and wish you all an exciting and highly
rewarding meeting and pleasant stay in Turin.
On behalf of the Organizing Committee
Arianna Carolina Rosa
Chair of the Organizing Committee

Previous Meetings
1970's1971 Lodz
1972 Paris
1973 Marburg
1974 Copenhagen
1975 Florence
1976 Paris
1977 London
1978 Lodz
1979 Stockholm

1980's1980 Visegard
1981 Hannover
1982 Bled1983 Brighton
1984 Florence
1985 Aachen
1986 Odense
1987 Strbske Pleso
1988 Copenhagen
1989 Breda

1990's1990 Kuopio
1991 Marburg
1992 Malaga
1993 Cologne
1994 Budapest
1995 Moscow
1996 Antwerp
1997 Seville1998 Lodz
1999 Lion

2000's2000 Nemi (Rome)2001 Turku
2002 Eger
2003 Noordwijkerhout
2004 Bergisch-Gladbach
2005 Bled2006 Delphi
2007 Florence2008 Stockholm
2009 Vulda

2010’s2010 Durham
2011 Sochi
2012 Belfast
2013 Lodz
2014 Lyon
2015 Malaga
2016 Florence
2017 Amsterdam
2018 Dublin2019 Krakow

2020’s2020 Online Symposium2021 Virtual Event
2022 HannoverVENUE
Accademia di Medicina di Torino - Via Po 18 10123 Turin, Italy

How to reach the Venue Google Maps: https:/GoogleMaps

Once you cross the entrance on Via Po 18 please be brave...the building is
still waiting the already planned renovation but if you go up the stairs on your left on thelanding you could admire the seventeenth-century fresco “La Crocifissione”,
attributed to Bartolomeo Guidobono (just restored and dedicated to the 22
Piedmontese doctors who sacrificed themselves during the COVID-19
pandemic), and when you reach the first floor you will find yourself
catapulted into a piece of history of Turin and medical sciences at theend of the corridor on you left!
The Accademia di Medicina di Torino, was born from the initiative of nineteen
doctors (including, Lorenzo Martini, Sacchetti, Pasero, Buosa, Averardi,
Schina, Moris, Ricci, Griffa, Gallo, Bertini, Barovero, Riberi, Barbaroux) which
in December 1819, in the midst of the Restoration, signed a request to meet periodically to debate
medical scientific topics and to publish the reports of these sessions. Granted the authorization in
February 1821, the first meetings could take place only in a strictly private manner at the private
home of del Prof. Gallo, no possibility of public meetings was allowed. The political situation of the
Savoy state reflected the revolutionary Italian context and the Austrian reaction. The public activityof the Accademia delle Scienze had been suspended; lessons at the University, already suspended fora certain time for fear of possible student demonstrations, had just been resumed. In 1832, themembers of the Private Medical-Surgical Society addressed a request to the Sovereign to obtainfunding for a magazine exclusively dedicated to medical topics on the work of the Medical-SurgicalSociety, today Accademia di Medicina di Torino. Four years later, in 1836, the first issue of the"Giornale delle Scienze Mediche", the official organ of the Medical-Surgical Society, published in
Turin by the bookseller Reviglio, finally was published. In 1838 there were 29 members and became
40 in 1848. in 1842, the Society obtained recognition by the State which provided two rooms at the
ground floor of Via Po 18, and guaranteed subsidization of publication costs and management
activities and above all the possibility of holding four public meetings a year in the presence of apolice delegate in charge of control. The availability of the two rooms in Via Po 18 allowed to seat apublic library.
On 10 February 1846, by royal decree signed Carlo Alberto, the Society was elevated to the rank ofRoyal Medical-Surgical Academy - Reale Accademia di Medicina. It has carried out its scientific andeditorial activity uninterruptedly until today.
According to the declared objective of the association to spread out
cultural themes and scientific renewal for the improvement of thePiedmontese medical class, the Academy Journal summarizes the entire
history of Piedmontese medicine from the early nineteenth century to thepresent day. The Academy had also a key role also in the formation of theFaculty of Medicine starting from 1848, when the new chairs of PathologicalAnatomy, Comparative Anatomy, Clinical Ophthalmology, Clinical of
Mental Diseases, History of Medicine and General Pathology were settled.
In 1865, when the capital was moved to Florence, the library collection was
moved to the south wing of Palazzo Madama, where the Senate library was
located. In those years, thanks to donations from private individuals and publishers, the number ofconserved volumes reached 90.000. The library came definitively back to via Po 18, on the first floor,in 1891. The collection reached 100.000 units and was accessible to the medical public and studentsof the faculty of Medicine, including also a section dedicated to health legislation and public healthpublications. During the bombing of Turin in July 1943 the library, was completely burned down andabout a thousand texts wererecovered.

Currently

thelibrary collection includes
11.761books

monographs

andcatalogued,

9.820 modern monographs(from 1831 to today), 1.941 old books (before 1830), 1.007 periodicals.
Nowadays the Academy of Medicine, guided by the President Prof.
Giancarlo Isaia, has still a pivotal role in cultural initiatives for the
training and updating of young doctors; with almost 100 Members itorganizes periodical scientific sessions opened not only to theMembers, but to the public.

GENERAL INFORMATION
Registration Desk
The registration desk is in the venue, at the first floor of Via Po 18 entered the Accademia di Medicina di Torino.
Please notice that no abstract book will be provided, but for any convenience you can print or save the pdf
file. The certificate of attendance will be sent by email at the end of the meeting. If you need a printed copy,
please inform the secretary when you complete the check-in, so we can provide. If you still need to pay theAffiliation fees to the Society, you can do it at the EHRS desk. For any question during the meeting, you willfind assistance at the Registration Desk, according to the Opening hours:
Thursday 09:30 – 17:00 h
Friday 08:30 – 17:30 hSaturday 08:30 – 12:00 h
WiFi ConnectionThe
wifi
connectionisguaranteedbytheEduroam(Education
Roaming)
service(https://eduroam.org/about/connect-yourself/).
Your password for your online identity is provided to you by your 'home' institution - where you are enrolled
in study or are employed.
If for any reason you cannot use the Eduroam service and you need a wifi connection, we could activate a
temporary Guest account to unito-guest wifi only if you required it by email atariannacarolinarosaEHRS2024@gmail.com NOT LATER THAN the 20th of May. The temporary account is strictly
personal, and you MUST have with you your Passport or Identity Card.
Oral Communications
Oral presentations are scheduled not to extend 15 min, which includes discussion. Please ensure that the filewith your presentation (pdf or Microsoft PowerPoint format) is handed over at the registration desk on themorning of your presentation at the latest.
The file of your presentation should be named as follows:‘PresentationTypeSessionNumber_Presenting Author.pptx’, e.g., ‘O1_Mustermann.pptx’.
Young Investigators Award
The finalists will present their work in the form of a 15-minute oral presentation (10-minute presentation + 5minute discussion) during the dedicated session on the 24th at 14.00.
The first and second-prize winners will be announced at the Gala Dinner, when all the finalists will receive a
certificate and a prize. Moreover, the first and second-prize winners will be invited to publish their papers in
Inflammation Research, following the normal reviewing process and payment of the fees if Open Access isdesired. In the cover letter, it should be indicated that Professor Bernhard Gibbs should be the editor in charge
as the EHRS-appointed editor. However, if another journal is more suitable for the work, an acknowledgmentthat the work was awarded with a Young Investigators Award must be included.
Flash Presentations
Oral presentations are scheduled not to extend 5 min, which includes 2 min discussion. Please ensure thatthe file with your presentation (pdf or Microsoft PowerPoint format) is handed over at the registration deskon the morning of your presentation at the latest.
The file of your presentation should be named as follows:‘PresentationTypeSessionNumber_Presenting Author.pptx’, e.g., ‘FP1_Mustermann.pptx’.
A Flash Presentation Award Panel will review all eligible Flash presentation (the Presenter should be registerd
as student) and Flash Presentations Prizes will be announced at the Gala Dinner and will receive a certificate
and a prize.

Local Organizing Committee
Arianna Carolina Rosa (Torino, IT); Katerina Tiligada (Athens, EL); Ilona Obara (Newcastle, UK); Elisa Benetti(Torino, IT); Valentina Boscaro (Torino, IT); Margherita Gallicchio (Torino, IT); Simona Spampinato (Torino, IT)
Scientific Committee
Pierre Chatelain (BE); Madeleine Ennis (UK); Bernhard Gibbs (DE); Rob Leurs (NL); Detlef Neumann (DE); Ilona
Obara (UK); Arianna Carolina Rosa (IT); Bassem Sadek (UAE); Holger Stark (DE); Satoshi Tanaka (JP); Katerina
Tiligada (EL)
Organizing Secretariat

eventuallyemail info@eventuallyevents.it
phone & whatsapp: +39.327.3752740
Abstract Evaluation & Student Bursary Award Committee
Arianna Carolina Rosa (IT); Bassem Sadek (UAE); Satoshi Tanaka (JP); Katerina Tiligada (EL); Madeleine Ennis(UK)
Young Investigators Award (YIA) Panel
Bernhard Gibbs (UK), Beatrice Passani (IT)Flash Presentations Award Panel
Detlef Neumann (DE), Satoshi Tanaka (JP), Katarzyna Popiolek-Barczyk (PL)Publication of the meeting’s proceedings
The proceedings of the meeting will be published in the journal Inflammation Research. All papers will be
published as abstract and should confirm to the style of the journal printed pages.

SOCIAL PROGRAMME
Guided City Centre Walk and Welcome reception
On Thursday the 23rd at 17:30 we will start a Guided City tour across the most stunning and important squares
of Turin.
We will discover the most iconic places of theunification of Italy walking through the small Piazza
Carlo Alberto and Piazza Carignano.
We will admire the charming Piazza San Carlo, a little piece of Paris in Italy and finally we will walk through theroyal Piazza Castello.
As a cherry on a cake, the roman area will
give an archaeological ending to our journeyjust in time to reach COMBO Torino, Corso
Regina Margherita 128, for the Welcome reception.
COMBO Torino is a dynamic, youthful, and eclectic
space obtained from the renovation of a historic firestation in the multiethnic neighborhood of Porta
Palazzo.
Porta Palazzo belongs to the historic centre of thecity, yet it preserves a character of its own (the urban
shape, the history, the settled people, the economic activities) which connotes it as a “popular” and multiethnic
district. Porta Palazzo owes its name to one of the gates of the city, the old postierla, San Michele, whichconnected the suburban districts with the market located in what once was called piazza delle Erbe, now piazza
Palazzo di Città. Throughout the centuries the postierla was replaced with astone gate, and in the 17th century it took over the Porte Palatine as themain northern access in a definite way. Porta
Palazzo was opened by 1701, under King
Vittorio Amedeo II, but the first plan of piazzadella Repubblica, however, was conceived within the so called “old city’s” city
plan reform, according to a project by architect Filippo Juvarra. Since the 19th
century, efforts to embellish and shape the square have been manifold and the square’s contours werecompleted in 1830.

As soon as the Juvarra exedra was completed, a spontaneous market sprung up,
because of its favourable location in correspondence to the Milan axis, but themarkets in Porta Palazzo settled once and for all in 29th August 1835, after a “Vicarial
Manifesto” which, due to a cholera epidemic, prohibited trade in the piazzas of
Palazzo di Città (once piazza delle Erbe) and Corpus. Today Porta Palazzo is the largest open-air market inEurope: it extends over a 51.300 sq m. area, houses a market which has a salesurface equal to 4.991 sq m. and over a thousand street vendors. The wholemarket area is visited by over 100.000 people, weekly.
Particularly

fascinatingthecoveredfoodmarketcalled“mercato

dell’Orologio”, built in 1916, and theGalleria Umberto I.

The latter originally was the Palazzo dei
Cavalieri, which housed the Mauriziano
Hospital from 1575 until 1884, and where islocated the ancient Mauriziano Pharmacy from
1575.
Closed to the Porta Palazzo market, the historical flea market called “Balon” takes
place. Since 1856, all Saturdays in a small version and every 2nd Sunday in the largest
and famous version “Gran Balon”, it is the perfect destination for enthusiasts andcollectors in search of trouvaille or for young students
or tourists in search of various curiosities.
Starting from the 1960s Porta Palazzo become a point of reference for the many
Italian immigrants who reached Turin in search of work. On Sundays, for example,
it was the place where workers were sought for construction, but also where one
could attend performances by improvised street artists.
The particular social context, the immense market and the urban and social degradation connected to themgreatly encouraged the presence of voluntary associations and social
commitment, such as the opening of SERMIG, also known as Arsenal of Peaceon May the 24th 1964 by Ernesto Olivero.
In the 1980s, Italian immigration from southern Italy was completely replacedby people of African and Asian origin. Starting from 1996, the entire Porta
Palazzo was the subject of a redevelopment project which led to a new road system and the recovery of someJuvarra buildings, but never lose the acquired “multiethnic skin”. in March 2006, the lighting ceremony of the
Paralympic Flame took place.

Gala Dinner
On Friday May 24, 2024 at 20:00 h we have our traditional Gala Dinner at the Società Canottieri Armida diTorino, Viale Virgilio 45, in the Parco delValentino

Founded in 1869, the Canottieri Armida contributed in 1888 withother rowing clubs to the establishment of the Italian Rowing Club,
nowadays known as the Italian Rowing Federation. One year later
the Armida Rowing Club introduced one of the best rowing boats
designed for four persons at the time, the Savoia.
In 1967 the Armida Rowing Club was awarded with the Golden Star for
sporting merits by the Italian National Olympic Committee (CONI).
In 2006 the Armida Rowing Club
resumedtheancient

traditionof

Venetian rowing, organizing courses and events to promote it. The venue
offers a meeting place from which it is possible to enjoy peacefully one of themost suggestive sceneries of Turin for 140 years.
The main building, which was once the home of the "Pavilion of French
Colonies" during the World Exhibition of 1911, is today supervised by thegovernment department
responsibleforenvironment
historical buildings.

the
and

INVITED SPEAKERS
PLENARY LECTURE - Histamine and other biogenic amines in food: fromscombroid poisoning to histamine intolerance
Dr. Oriol Comas-Basté – University of Barcelona, Barcelona (Spain)

GBW LECTURE - Mechanisms of mast cell inflammatory mediator secretion: an
updateProf. Ulrich Blank – Institut National de la Santé et de la Recherche Médicale(INSERM) – Paris (France)

KEYNOTE LECTURE - 25 years of H4 receptor research
Prof. Katerina Tiligada – University of Athens – Athens (Greece)

ROUND TABLE Anti-histamines in the real-world: pharmacovigilance in the spotlight
H1-receptor affinity of psychotropics and risk of weight gain and metabolic
disordersProf. Virginio Salvi – Policlinico Gemelli, Università Cattolica del Sacro Cuore –Roma (Italy)

ROUND TABLE Anti-histamines in the real-world: pharmacovigilance in the spotlight
Where has rantidine gone?
Dr. Marco Tuccori – Azienda Ospedaliera Universitaria Pisana – Pisa (Italy)

ROUND TABLE Anti-histamines in the real-world: pharmacovigilance in the spotlight
Pitolisant, a novel inverse agonist at the H3 histamine receptor: efficacy andsafetyProf. Valerio Brunetti – Policlinico Gemelli, Università Cattolica del Sacro Cuore –Roma (Italy)

PROGRAMME
23 MAY 2024
09:00 EHRS & HRSE COUNCIL MEETINGS
09:30 Registration
10:45 OPENING CEREMONY Arianna Carolina Rosa (IT) & Katerina Tiligada (EL)11:15 Foundation of the HRSE – Holger Stark (DE) & Detlef Neumann (DE)11.30 PLENARY LECTURE Chairperson: Arianna Carolina Rosa (IT)Histamine and other biogenic amines in food: from scombroid poisoning to histamine intolerance – Oriol
Comas-Basté (Barcelona, Spain)
12:30 Welcome buffet
13:15 HONORARY MEMBERSHIP CEREMONY Chairperson: Katerina Tiligada (EL)
Orations by Paul Chazot (UK), Agnieszka Fogel (PL), M. Ennis (UK), Detlef Neumann (DE)
14:00 Scientific session I – Neuronal histamine Chairpersons: Beatrice Passani (IT) & Ling Shan (NL)
Oral presentations
14:00 The roles of histamine and histamine H1 receptor in hypocretin neuron development and behavior inzebrafish – Pertti Panula (Helsinki, Finland)
14:15 Histaminergic neuronal activity controls food consumption: a chemogenetic study – Gustavo Provensi(Florence, Italy)
14:30 Histaminergic neurons modulate vulnerability and resilience to psychological stress – Beatrice Passani(Florence, Italy)
14:45 Exploring the interplay of histamine H3 receptors and mTORC1: Implications for neuropathic pain
relief – Paul Chazot (Durham, UK)Flash presentations
15:00 The role of glial cells activation in the analgesic effects of histamine H3 receptor antagonist, E-98 –In
vivo and in vitro studies – Katarzyna Popiolek-Barczyk (Krakow, Poland)
15:10 EHRS & HRSE General Assemblies
17:15 End of first day
SOCIAL PROGRAMME
17:30 Guided City Centre Walk
19:30 Welcome reception______________________
24 MAY 2024
08:30 Scientific session II – Neuronal histamine Chairpersons: Pertti Panula (FI) & Gustavo Provensi (IT)
Oral Presentations
08:30 The roles of histaminergic neural circuits in the precise regulation of CNS disorders and its
mechanisms – Zhong Chen (Hangzhou, China)
08:45 Postsynaptic histamine H3 receptors in ventral basal forebrain cholinergic neurons modulatecontextual fear memory – Yanrong Zheng (Hangzhou, China)
09:00 Whole brain output and input mapping of mouse histaminergic network – Wenkai Lin (Hangzhou,
China)

09:15 Histamine-4 receptor antagonist inhibits pro-inflammatory microglia and prevents the progression ofParkinson-like pathology: A new therapeutic strategy – Ling Shan (Amsterdam, The Netherlands)
09:30 Histamine H2 receptor deficiency in parvalbumin-positive neurons leads to attention deficit
hyperactivity disorder-like phenotypes – Dadao An (Hangzhou, China)
Flash Presentations
09:45 Effects of H3R antagonist E169 on autophagy and autism-like behavioral phenotypes in BTBR mousemodel of autism – Nermin Eissa (Abu Dhabi, UAE)
09:50 The H3R antagonist E159 attenuates neuroinflammation and autistic-like behaviours in BTBR T+ tf/J
mouse model of autism – Nermin Eissa (Abu Dhabi, UAE)
09:55 An H2R-dependent medial septum histaminergic circuit mediates feeding behavior – Lingyu Xu(Hangzhou, China)
10:00 Histamine receptors: Novel drug targets for schizophrenia– Weiwei Hu (Hangzhou, China)
10:05 Coffee break
10:35 GB WEST LECTURE Chairperson & Introduction of the speaker: Madeleine Ennis (Belfast, UK)
Mechanisms of mast cell inflammatory mediator secretion: an update – Ulrich Blank (Paris, France)
11:35 Scientific session III – Histamine, mast cells & basophils Chairpersons: Susanne Mommert (DE) &Mitsunobu Mio (JP)Oral Presentations
11:35 Oral desensitization to peanut differentially affects the reactivity of human basophils to IgEdependent stimulation – Bernhard Gibbs (Canterbury, UK)
11:50 GPR35 mediates stabilization of mast cells – Satoshi Tanaka (Kyoto, Japan)
12:05 Mast cells are differently affected by ST-2309 and ciproxifan, H3R blockers – Agnieszka Fogel (Lodz,
Poland)12:20 Scabies mites, what’s itching – Does the interplay between parasite-derived pruritogens and host
MRGPRX2 explain the intense itching in human scabies? – Franco Falcone (Giessen, Germany)
12:35 Scientific session IV – Drug design & molecular targeting Chairpersons: Rob Leurs (NL) & Paul
Chazot (PL)
Oral Presentations
12:35 Structural basis of agonist recognition at the H4 receptor – Rob Leurs (Amsterdam, The Netherlands)
12:50 Pharmacological characterization of seven human histamine H3 receptor isoforms – Meichun Gao(Amsterdam, The Netherlands)
Flash Presentations
13:05 Distinct G protein and β -arrestin recruitment to seven histamine H3 receptor isoforms Meichun Gao(Amsterdam, The Netherlands)
13:10 Reaching beyond the UV spectrum – A pharmacological profile of a red-shifted H1R photocaged
ligand – Ivana Josimovic (Amsterdam, The Netherlands)
13:15 Tetrazine-based building blocks for Click chemistry on histamine H3 receptor ligands – Martin Moriz
Stark (Düsseldorf, Germany)
13:20 Buffet lunch

14:00 YOUNG INVESTIGATORS AWARDS YIA Panel: Bernhard Gibbs (UK), Beatrice Passani (IT)

14:00 Histamine receptor H4 modulates the expression of Na+/H+ (NHE)3 exchanger in the renal proximal
tubular cell line HK-2 – Chiara Gerbino (Turin, Italy)
14:15 VUF26063: a second-generation photoswitchable ligand to optically control the histamine H3 receptor– Ivana Josimovic (Amsterdam, The Netherlands)
14:30 Multitargeting compounds for neurodegenerative diseases: Dual H3R/ChEs ligands with chelating
properties – Flávia Barrio Lopes (São Paulo, Brazil)
14:45 Do histaminergic neurons express adenosine 1 receptors? Comparative analysis with reference tohippocampal dentate gyrus granular cells – Lea Wegmann (Düsseldorf, Germany)
15:00 Scientific session V in memory of Prof. Pier F. Mannaioni – Histamine in the heart & the kidney
Chairpersons: Anita Sydbom (SE) & Joao Fernandes (BR)
15:00 Oration in memory of Prof. Pier F. Mannaioni – Roberto Fantozzi (IT)
Oral Presentations
15:10 Haloperidol, clozapine and mirtazapine are functional antagonists at histamine receptors in humanatrial preparations – Jonas Schlicht (Halle, Germany)Flash Presentations
15:25 Contractile effects of histamine in mice overexpressing H1-histamine receptors and H2-histamine
receptors in the atrium – Hoai Pham (Halle, Germany)
15:30 Temperature sensitive contractile effects of histamine in mice overexpressing H1-histamine receptors
in the atrium – Peter Grundig (Halle, Germany)
15:35 Different role of histamine H1 and H4 receptors on the expression of aquaporin (AQP)1 and AQP7 in
the human renal proximal tubule cell line HK-2 – Marta Molino (Florence, Italy)
15:40 Investigation of the cross-talk between histamine and renal CLC chloride channels and transporters ina mouse model of diabetic nephropathy – Arianna Carolina Rosa (Turin, Italy)
15:45 Coffee break
16.15 Group picture
16:30 Scientific session VI – Histamine in the eye Chairpersons: Holger Stark (DE) & & Nermin Eissa (UAE)
Oral Presentations
16:30 H4 histamine receptor upregulation and inflammatory responses in an in vitro model of diabetic
retinopathy – Paul Chazot (Durham, UK)
16:45 Histamine stimulates calcium-dependent transmembrane cation current through H1R-Gq/11 pathway
in human retinal glial Müller cells – Seva Telezhkin (Newcastle upon Tyne, UK)
17:00 H3R antagonist-CA inhibitor hybrid compounds in a rabbit model of transient ocular hypertension– Laura Lucarini (Florence, Italy)
Flash Presentations
17:15 Evaluation of fibrotic markers in an animal model of ocular hypertension treated with a histamine
H3R/NO hybrid compound – Silvia Sgambellone (Florence, Italy)
17:20 Photoswithchable compounds in a transient ocular hypertension (OHT) model in new zealand white(NZW) rabbit – Silvia Marri (Florence, Italy)
17:25 Study of microRNA involved in ocular ischemia pathway – Serafina Villano (Florence, Italy)
17:30 Flash presentation award Panel meeting Detlef Neumann (DE), Satoshi Tanaka (JP), Katarzyna
Popiolek-Barczyk (PL)17:30 YIA Panel meeting Bernhard Gibbs (UK), Beatrice Passani (IT)

17:45 End of second day
SOCIAL PROGRAMME
20:00 Gala Dinner______________________
25 MAY 2024
08:45 KEYNOTE LECTURE Chairperson: Holger Stark (DE) - 25 years of H4 receptor research – Katerina
Tiligada (Athens, Greece)
09:30 Scientific session VII – Histamine in inflammation and immunity Chairpersons: Agnieszka Fogel(PL) & Laura Lucarini (IT)
Oral Presentations
09:30 Histamine upregulates the expression of MMP12 in human M2 macrophages – Susanne Mommert(Hannover, Germany)
09:45 Assessing the anthelmintic potential of antihistamines H1 against Angiostrongylus cantonensis – Joao
Paulo Fernandes (São Paulo, Brazil)
Flash Presentations
10:00 Cyclophosphamide auguments humoral immunity and drug resistance against L-asparaginase– Mitsunobu Mio (Okayama, Japan)
10:05 Coffee break
10:30 Round Table · Anti-histamines in the real-world: pharmacovigilance in the spotlight Moderator:
Armando Genazzani (IT)10:30 Introduction
10:35 H1-receptor affinity of psychotropics and risk of weight gain and metabolic disorders – Virginio Salvi(Milano, Italy)
10:50 Where has rantidine gone? – Marco Tuccori (Pisa, Italy)
11:05 Pitolisant, a novel inverse agonist at the H3 histamine receptor: efficacy and safety – Valerio Brunetti(Rome, Italy)
11:20 Discussion
11:40 Closing remarks – Rob Leurs (NL) & Arianna Carolina Rosa (IT)12:00 End of the congress

INVITED SPEAKERS ABSTRACT
PLENARY LECTURE HISTAMINE AND OTHER BIOGENIC AMINES IN FOOD: FROM SCOMBROID
POISONING TO HISTAMINE INTOLERANCE
O. Comas-Basté, S. Sánchez-Pérez, M.T. Veciana-Nogués, M.L. Latorre-Moratalla, M. Carmen
Vidal-Carou

Histamine is present in a wide range of foods in highly variable concentrations, which are the main
exogenous source of this compound. The main route for histamine formation in foods is the decarboxylationof the amino acid histidine through the action of L-histidine decarboxylase, an enzyme of bacterial origin.
Therefore, foods that potentially contain high levels of histamine are: a) those microbiologically altered,such as fish and meat, or derived products that may have been preserved or processed in unsuitably hygienic
conditions; and b) fermented products, in which the bacteria responsible for the fermentation process may
also have aminogenic capacity.
Although histamine has important physiological functions in the body, it can pose a health risk wheningested in high levels. Histamine intoxication is caused by the intake of foods with high levels of histamine.
This food intoxication is characterized by occurring in outbreaks and having a short incubation period, withsymptoms that are generally of low/moderate severity and remit in a few hours. Although histamine
intoxication has been extensively studied in recent decades, unresolved questions remain, concerning, forexample, the variable histamine concentrations in the foods triggering outbreaks, or the heterogeneity in the
degree and type of adverse effects. On the other hand, histamine intolerance arises from reduced histamine
degradation capacity in the intestine due to impaired diamino oxidase (DAO) enzyme activity, leading to its
accumulation in plasma and the appearance of adverse effects. The clinical manifestations of histamine
intolerance consist of a wide range of nonspecific gastrointestinal and extraintestinal symptoms, which canappear in susceptible individuals after the ingestion of foods containing normal or even low histamine levels.
Currently, the main strategy to avoid the symptoms of histamine intolerance is to follow a low-histamine
diet, while the supplementation with exogenous DAO enzyme has recently been postulated as acomplementary treatment to enhance dietary histamine degradation in the intestines.
Although interest in histamine intolerance has considerably grown in recent years, more scientific evidence
is still required to help define, diagnose and clinically manage this condition. In this conference, a glanceon histamine intoxication will be performed, as well as the analysis of some uncertainties historicallyassociated to histamine intoxication outbreaks that may be better explained by the existence ofinterindividual susceptibility to ingested histamine. Moreover, an updated review on histamine intolerance
will be delivered, mainly focusing on its etiology and the existing diagnostic and treatment strategies.

Departament de Nutrició, Ciències de l’Alimentació i Gastronomia, Campus de l’Alimentació de Torribera,
Universitat de Barcelona, Av. Prat de la Riba 171, Santa Coloma de Gramenet, 08921, Spain
InsItut de Recerca en Nutrició i Seguretat Alimentària (INSA·UB), Universitat de Barcelona, Av. Prat de la
Riba 171, Santa Coloma de Gramenet, 08921, Spain
oriolcomas@ub.edu

INVITED SPEAKERS ABSTRACT
GBW LECTURE MECHANISMS OF MAST CELL INFLAMMATORY MEDIATOR SECRETION: AN
UPDATE
Ulrich Blank
Following the milestone finding of J.F. Riley & G.B West recognizing mast cells as the major
source of histamine more than 7 decades have past and mast cells are now well recognizedactors of inflammatory and immune responses. Besides histamine, they are known to release
upon stimulation a plethora of inflammatory mediators prestored either in their cytoplasmic
granules or after new synthesis including various lipid compounds as well as cytokines andchemokines. Besides their important task of launching the inflammatory cascade locally intissues, these mast cell products also contribute to the regulation of the accompanying immune
response and the crosstalk with other inflammatory cells. Our group has been studying for many
years the signalling events leading to the release of mediators following allergic stimulation
through the high affinity IgE receptor (FceRI) focusing on receptor-distal event such as those
implicated in the fusion of secretory granules with the plasma membrane. More recently webecame also interested in studying the mechanisms regulating the production, secretion andvesicular trafficking of CCL2, also called monocyte chemoattractant protein-1 (MCP-1), a
major chemokine produced by mast cells. My talk will provide you with an overview and updateon these late signalling and trafficking events governing mast cell mediator release.
Université Paris Cité, Laboratoire d'Excellence Inflamex, Centre de Recherche surl'Inflammation, INSERM U1149, CNRS EMR8252, 75018 Paris, France.
Email: ulrich.blank@inserm.fr

INVITED SPEAKERS ABSTRACTKEYNOTE LECTURE 25 YEARS OF HISTAMINE H4 RECEPTOR RESEARCH
Katerina Tiligada
Histamine has been one of the most studied substances in biomedical sciences since the early
1900s. The recognition of its multifaceted functions in health and disease that are elicited via thehistamine H1-4 receptors (H1-4R) laid the basis for the development and the clinical exploitation of
HR-targeting therapeutics. In 2000, the discovery of the H4R by exploiting molecular biology
approaches revived both the academic and the industrial interest in the field. This novel HR was
shown to be primarily expressed in immune cells and to mediate mast cell and eosinophil
chemotaxis. Subsequent intense research, largely assisted by the first highly selective H4R
antagonist JNJ7777120 revealed the functional role of the H4R in immunocompetent cells and in
inflammation, and characterized it as the immunomodulatory HR and as a promising emerging
target for the treatment of chronic inflammatory diseases. Despite the complex H4R pharmacology,
as exemplified by the β-arrestin bias signalling, and the species- and strain-dependent effects of
H4R ligands in preclinical models of inflammation, a number of H4R-targeting compounds
advanced into clinical testing in patients with atopic dermatitis, pruritus, asthma, rheumatoid
arthritis and vestibulopathy. The hitherto failure of H4R antagonists to enter late clinical trials may
hold back the enthusiasm of the big pharma industry to further advance H4R-targeting compounds
to clinical testing. However, the development of selective H4R ligands remains an ongoingendeavour. Equally, continuing efforts using standard pharmacological approaches and cuttingedge methodologies aim to better understand the (patho)physiological significance of the receptor.
These studies would benefit the dissection of H4R molecular properties, the rational design of new
generation H4R ligands and their value as new therapeutic options for unmet medical needs ininflammation-driven disorders.
This lecture was supported by SARG NKUA, Greece
Department of Pharmacology, Medical School, National and Kapodistrian University of Athens,
Athens, Greece
E-mail: aityliga@med.uoa.gr

INVITED SPEAKERS ABSTRACTROUND TABLE -H1-RECEPTOR AFFINITY OF PSYCHOTROPICS AND RISK OF WEIGHT GAIN ANDMETABOLIC DISORDERS
Virginio Salvi

People with severe mental illness are more frequently affected by obesity, diabetes and dyslipidemias than thegeneral population, eventually resulting in greater cardiovascular disease morbidity and mortality. This is due
to several factors such as genetic liability and unhealthy lifestyles; however, the use of psychotropic medication
also plays a central role. Specifically, the use of antipsychotics and to a lesser extent antidepressants and moodstabilizers, put the patients at risk for weight gain and metabolic disorders.
Histamine plays a role in inducing satiety through its interaction with histamine H1-receptors in the
hypothalamus. Several antipsychotics are H1-receptor antagonists, and some studies have highlighted an
association between their affinity at histamine H1-receptor and weight gain. Specifically, antipsychotics suchas olanzapine and clozapine, that share potent anti-histaminergic activity, produce a very relevant weight gain
in treated patients. These antipsychotics also produce glucose metabolism dysregulation, thus increasing the
likelihood of type 2 diabetes. This effect is seen both as a consequence of the weight gain and due to theblockade of histaminergic receptors located on pancreatic beta cells, resulting in a reduced production of
insulin.
In more recent years, an association between anti-histaminergic activity and weight gain or metabolic
syndrome has been found also for some antidepressant with high H1-receptor affinity, such as amitriptyline
and mirtazapine.
In conclusion, weight gain and metabolic abnormalities observed during treatment with psychotropics isgreatly explained by the capacity of these medications to effectively block the histamine H1 receptor, thus
promoting food intake and eventually metabolic dysregulation.
Department of Mental Health and Addiction, ASST di Crema. Crema (CR), Italy
Email: virginiosalvi@gmail.com

INVITED SPEAKERS ABSTRACTROUND TABLE -WHERE HAS RANITDINE GONE?
Marco Tuccori
Ranitidine has been a widely used medication for decades. It belongs to the class of H2-receptor antagonists
and is primarily prescribed to reduce stomach acid production in patients with conditions such as heartburnand stomach ulcers.
In 2019, laboratory tests revealed the presence of N-Nitrosodimethylamine (NDMA), a potentiallycarcinogenic compound, in ranitidine formulations. NDMA is a probable human carcinogen, and its levels
were found to be unacceptable in some batches of ranitidine. Although the exact source of this impurity
remains unclear, it is believed that NDMA may form during the degradation of ranitidine, especially whenstored at higher temperatures or over time. The impurity levels in some ranitidine formulations were found toincrease over time, raising concerns about patient safety.
The discovery prompted regulatory agencies to take action. Major drug regulators, including the European
Medicines Agency (EMA) and the US Food and Drug Administration (FDA), suspended the sale of ranitidine
in 2020 due to the NDMA contamination. The FDA recommended manufacturers withdraw all prescription
and over-the-counter ranitidine drugs from the market immediately.
Despite its suspension in many countries, ranitidine remains freely available in India. It is sold over the counter
without requiring a prescription. The low cost and lack of awareness about potential risks contribute to its
continued use in the country. A UK-based pharmaceutical company is exploring the possibility of bringing
back ranitidine after the first manufacturer of the active ingredient restored its 'certificate of suitability.
However, other manufacturers have no plans to reintroduce the product.
In conclusion, the withdrawal of ranitidine underscores the importance of rigorous safety assessments andcontinuous monitoring of pharmaceutical products quality to protect public health.
Unit of Adverse Drug Reaction Monitoring – University Hospital of Pisa, Via Roma 55, 56126 Pisa - Italy
Email: marco.tuccori@gmail.com

INVITED SPEAKERS ABSTRACTROUND TABLE PITOLISANT, A NOVEL INVERSE AGONIST AT THE H3 HISTAMINE RECEPTOR:EFFICACY AND SAFETY
V. Brunetti
Pitolisant, a selective H3 receptor (H3R) antagonist/inverse agonist, activates histaminergic neurons
predominantly located in the cerebral cortex, hypothalamus, hippocampus, and basal ganglia. These
neurons play a crucial role in promoting wakefulness and decreasing sleep propensity. Narcolepsy
and obstructive sleep apnea syndrome (OSAS) are debilitating sleep disorders characterized byexcessive daytime sleepiness (EDS), significantly impacting daily functioning and quality of life.
Narcolepsy, a rare neurological disorder, manifests with EDS and brief episodes of muscle weakness(cataplexy). OSAS, a prevalent disorder, involves intermittent upper airway collapse during sleep,
resulting in reduced blood oxygen saturation, sleep fragmentation, and consequent EDS.
Pitolisant has emerged as a promising therapeutic intervention for managing EDS associated withthese conditions. Clinical trials consistently demonstrate significant enhancements in both objective
and subjective measures of wakefulness in patients with narcolepsy and OSAS.
The safety profile of pitolisant seems favorable, with predominantly mild to moderate and transient
adverse events, including headache, insomnia, anxiety, and nausea. Notably, pitolisant lacks the abusepotential and cardiovascular risks often linked with conventional wake-promoting agents.
Moreover, pitolisant demonstrates minimal potential for drug-drug interactions, facilitating
coadministration with other medications commonly used in narcolepsy and OSAS.
In conclusion, pitolisant presents a promising therapeutic option for addressing sleepiness innarcolepsy and OSAS, offering both efficacy and safety advantages. Further long-term investigations
are warranted to elucidate its sustained efficacy and safety profile, particularly in real-world clinicalscenarios.
Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome 00168, Italy
Università Cattolica del Sacro Cuore, Rome 00168, Italye-mail: v.brunetti2509@gmail.com

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION I – NEURONAL HISTAMINE
THE ROLES OF HISTAMINE AND HISTAMINE H1 RECEPTOR IN HYPOCRETIN
NEURON DEVELOPMENT AND BEHAVIOR IN ZEBRAFISH
P. Panula, P. Chalas, Y. Yao, Y.-C. Chen, M. Sundvik
Histamine and hypocretin (hcrt) systems are closely linked hypothalamic regulators of e.g. alertness
and sleep in vertebrates including humans. The number of neurons expressing the histaminesynthesizing enzyme histidine decarboxylase (hdc) has been reported to be abnormally high innarcoleptic patients, whereas the number of hcrt cells is strongly reduced.
Using gene-modified zebrafish generated with the CRISPR-Cas method lacking either H1 receptor(hrh1) or hdc, we analyzed the number of hypothalamic hypocretin neurons using
immunohistochemistry for hypocretin and in situ hybridization for hcrt mRNA. Quantitative behavioral
methods were used to assess sleep-like behavior and motor responses in 6-7 days post fertilization (dpf)zebrafish larvae.
Both hdc-/- and hrh1-/- larvae displayed largely normal (similar to wild-type littermates) sleep and motor
behavior. Both hdc-/- and hrh1-/- larvae had abnormally few hcrt neurons in the brain. In hrh1-/zebrafish, the number of hcrt neurons was abnormally low during the early larval stage and at 20 dpf,
but did not differ from wild-type fish during adulthood, suggesting delayed development.
The results suggest that the histamine system and hrh1 are not needed for normal sleep-like resting stateand motor behavior in zebrafish. Histamine and hrh1 are required for normal early development of hcrt
neurons, in contrast with previously published results on other models of zebrafish lacking hrh1 or hdc,
but in agreement with our previous results using treatment of larvae with hrh1 inverse agonist
pyrilamine or alpha-methylfluorohistidine, a suicide inhibitor of hdc.
Department of Anatomy, University of Helsinki, 00290 Helsinki, Finland
pertti.panula@helsinki.fi

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION I – NEURONAL HISTAMINEHISTAMINERGIC NEURONAL ACTIVITY CONTROLS FOOD CONSUMPTION: A
CHEMOGENETIC STUDY
A. Costa, V. Sordi, M.B. Passani, G. Provensi

Food consumption is regulated by two systems: the homeostatic, driving the motivation to eat following
depletion of energy stores, and the hedonic, modulating the desire to eat, particularly palatable foods, evenin periods of energy abundance. Previous reports revealed that neuronal histamine (HA) plays a role on
feeding behavior, however, most studies were based on genetic or pharmacological manipulations which
present technical limitations. We aimed to investigate the impact of modulating endogenous HA
neurotransmission on food consumption using a chemogenetic approach. Mice expressing a Cre
recombinase under histidine decarboxylase promoter control (Hdc-Cre) received bilateral injections of viral
vectors carrying Cre-dependent excitatory (hM3Dq) or inhibitory (hM4Di) designer receptors exclusively
activated by designer drugs (DREADDs) into the turberomamillary nucleus. Four weeks after injections,mice received systemic administration of DREADDs ligand Clozapine-N-Oxide (CNO, 2 mg/kg, i.p.).
Normal or palatable (60% fat) chow intake was measured in the fasting-refeeding paradigm. Opposite
effects emerged following acute HA system modulation: silencing of HA neurons elicited food intake,whereas their activation suppressed food intake. Repeated CNO administration (2 mg/kg, once daily, 10days) to mice expressing excitatory DREADDs not only reduced the cumulative amount of food consumed
but also determined a significant reduction of mice’ body weight. Finally, chemogenetic stimulation of HA
neurons did not elicited aversion in the conditional place preference task, suggesting that the decrease infood intake is not caused by nausea or malaise. In conclusion, our results confirm and expand previous
reports regarding the role of neuronal HA in regulating feeding behaviour and pave the way for future studies
to deconstruct specific histaminergic neural pathways involved, as well as regulatory mechanisms
underlying feeding control.

Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), SecDon of
Pharmacology and Toxicology, University of Florence. Viale G. Pieraccini 6, CAP 50139, Firenze, FI, Italy.
gustavo.provensi@uniﬁ.it

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION I – NEURONAL HISTAMINEHISTAMINERGIC NEURONS MODULATE VULNERABILITY AND RESILIENCE TO
PSYCHOLOGICAL STRESS
A. Costa, V. Sordi, G. Provensi, M.B. Passani
Exposure to stress represents a major condition conferring risk for different psychiatric disorders,characterised by dysfunctions of cognitive, emotional, and social domains. However, not everyone who
experiences an adverse event succumbs to negative outcomes and enters a pathological state, as someindividuals are highly vulnerable to the pathological consequences of stress exposure, whereas others appear
to be resilient. In this regard, knowledge of TMN histamine (TMNHA) neurons role in stress vulnerability
and resilience is missing. To understand the involvement of TMNHA neurons in the development of stressinduced impairments, mice underwent an ethologically valid stress protocol, the chronic social defeat stress(CSDS) and tested for cognitive impairments. To question the effect of activating/inhibiting TMNHA
neurons, chemogenetic, pharmacological and genetic approaches were used: 1 Cre-dependent excitatory(hM3Dq) or inhibitory (hM4Di) viral constructs were injected in the TMN of Hdc-Cre mice and the activatorclozapine-NO (CNO) injected i.p. during the CSDS; 2) the H3R antagonist pitolisant (10mg/kg i.p.) or theagonist VUF16839 (5 mg/kg i.p.) were injected during the CSDS; 3) Hdc-ko and WT mice were subjectedto the CSDS. Behavioural consequences of CSDS were evaluated with non-rewarded, spontaneous social
and learning tasks and compared to those of non-stressed mice. mRNA levels of HA producing/metabolizing
enzymes and HA receptors were analysed in the TMN, hippocampus and frontal cortex of stressed versus
control mice. We found alterations of HA receptors and metabolic enzymes mRNA transcripts in the brainof stressed mice. Crucially, activation of TMNHA neurons promoted resilience to CSDS-induced social andcognitive impairments, whereas chemogenetic, genetic or pharmacological silencing of TMNHA neurons
induced vulnerability. Our results reveal that interventions targeting the HA system promotes coping andlong-term resilience by normalizing stress-affected behaviours
Dip. Scienze della Salute Università di Firenze, Viale Pieraccini 6 Firenze 50139 (Italy)

beatrice.passani@uniﬁ.it

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION I – NEURONAL HISTAMINEEXPLORING THE INTERPLAY OF HISTAMINE H3 RECEPTORS AND mTORC1:IMPLICATIONS FOR NEUROPATHIC PAIN RELIEF
I. Obara, I. Alrashdi, P. Chazot

Histamine H3 receptors (H3Rs), which are expressed in the central nervous system (CNS), seem to play asignificant role in the regulation of chronic pain processes. However, the exact mechanisms explaining the
involvement of H3Rs in the regulation of neuropathic pain that develops after nerve injury are not wellunderstood. One of the proposed mechanisms involves the inhibition of the Akt/GSK-3β pathway, as wellas the subsequent inhibition of the mammalian target of rapamycin complex 1 (mTORC1) pathway, resulting
from the H3Rs antagonism and leading to neuroprotective effects. Thus, the present study focused on thepossible interactions between H3R and mTORC1 and its downstream effectors that may have implicationsin the regulation of neuropathic pain symptoms. Adult male C57BL/6J mice (n=6/group) were subjected toperipheral neuropathy induced by chronic constriction injury (CCI) of the sciatic nerve and were treatedwith a CNS-sparing H3R antagonist/reversible inverse agonist, PF-0868087 (10 mg/kg once every 24 h for
4 days, i.p.; Novartis). Control animals were not subjected to CCI (shams) and/or were treated with 0.1 M
citrate buffer (vehicle). Western blot analyses, performed on the L4-L6 spinal cord and sciatic nerve samples,
showed that PF-0868087 reduced mTORC1 activity in neuropathic mice, as observed by the inhibition ofribosomal S6 proteins, p70 ribosomal protein S6 kinase and eukaryotic initiation factor 4E-binding protein.
This data strongly aligns with our earlier behavioural studies showing antinociceptive efficacy of PF0868087 in neuropathic mice and emphasises the significant role of the mTORC1 pathway in theantinociceptive effect of H3R antagonists, suggesting a histamine-independent mechanism. The present
findings, therefore, shed new light on H3R and its signalling pathways in the context of neuropathic pain
and suggest that H3R is a potential target in therapy for this type of chronic pain, where mTORC1 signalling
may play a critical role.
School of Pharmacy and Translational and Clinical Research Institute, Newcastle University, NewcastleUpon-Tyne, NE1 7RU, UK
ilona.obara@ncl.ac.uk

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION I – NEURONAL HISTAMINE

THE ROLE OF GLIAL CELLS ACTIVATION IN THE ANALGESICEFFECTS OF HISTAMINE H3 RECEPTOR ANTAGONIST, E-98 – IN
VIVO AND IN VITRO STUDIES.

Katarzyna Popiolek-Barczyk*, Maciej Degutis, Dorota Łażewska, Justyna Barut, Magdalena Białoń,Żaneta Broniowska, Gniewomir Latacz, Katarzyna Szczepańska, Tadeusz Karcz, Katarzyna KiećKononowicz, Katarzyna Starowicz
Neuropathic pain is a pathological disorder caused by lesions or diseases of the somatosensory nervous
system, where profound central inflammation is observed, involving the CNS-resident non-neuronalcells, mainly microglia and astrocytes. A growing body of evidence indicates the histaminergic system
is a therapeutic target for pain management. Our study aimed to determine the analgesic effects ofhistamine H3 receptor (H3R) antagonist in neuropathic mice and its influence on glia activation, whichmight underpin its potential efficacy. We used chronic constriction injury (CCI) to model neuropathic
pain. We investigated the effects of novel H3R antagonist, E-98 1-(7-(4-chlorophenoxy)heptyl)-3methylpiperidine)) after single injection (1, 5, 10, 20 mg/kg) on mechanical (von Frey) and thermal(cold plate) stimuli in CCI-exposed (day 14th) mice, along with the possible participation of spinal H1R,
H2R, and H4R. Moreover, the effect of chronic E-98 (10 mg/kg) treatment (twice daily, 7 days) wasinvestigated, and its influence on glia activation in the lumbar spinal cord (Western blot). The antiinflammatory properties of E-98 (10 µM) were screened (ELISA) in microglia and astrocytes primarycell cultures. We assessed the presence of H3R in the spinal cord of neuropathic mice and in the primarycultures of glial cells. E-98 attenuated nociceptive responses and this effect was reversed by pretreatment
with pyrilamine, an H1R antagonist, and ranitidine, an H2R antagonist, but not JNJ7777120, an H4R
antagonist. Chronic treatment also produced potent analgesia correlated with reduced microglia, but not
astroglia, activation. In vitro studies showed a decreased IL-6 level in both glial cell cultures. We
observed co-localization of H3R with neurons, as well as microglia and astrocytes, in the spinal cord andcell cultures. Our studies explore the mechanism of analgesic action of H3R antagonists and might help
identify innovative therapeutic interventions for neuropathic pain.
Acknowledgements Work was financed by a grant from the National Science Centre, Poland,
SONATA 2019/35/D/NZ7/01042.

*

Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Neurochemistry, Smetna
12, 31-343, Krakow, Poland

popiolek@if-pan.krakow.pl

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINE

THE ROLES OF HISTAMINERGIC NEURAL CIRCUITS IN THE
PRECISE REGULATION OF CNS DISORDERS AND ITS MECHANISMS
Zhong Chen

Histamine is an important neurotransmitter in the brain. Recently, my team has employed thefluorescence micro-optical sectioning tomography (fMOST) technique to construct thewhole-brain mapping of histaminergic projections in mice (PNAS, 2023a), based on which
we further analyze the differential roles of different histaminergic neural projections infeeding (Curr Biol, 2022), fear memory (Cell Rep, 2023) and various behaviors. Meanwhile,by using Cre-Loxp technology to selectively deplete histamine receptors in different brain
regions and types of cells, we revealed the cell-type-specific characteristics of histamine
receptors in schizophrenia (Nat Commun, 2021; PNAS, 2023b) and cerebral ischemia (J Exp
Med, 2021). In addition, proteomic techniques are employed to identify downstream
signaling pathways of histamine receptors and found the critical role of autophagy in theintracellular regulation by histamine H3 receptor (Nat Commun, 2014; Autophagy, 2014;2017a; 2017b; JCB, 2019). The above studies systematically elucidate the roles ofhistaminergic neural projections in different CNS disorders and reveal the cell-type-specificfunctions of histamine receptors, which may shed light on future precise interventions for
CNS disorders.
Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province,
College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou
310053, China.
*Correspondence to Zhong Chen (chenzhong@zju.edu.cn)

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINEPOSTSYNAPTIC HISTAMINE H3 RECEPTORS IN VENTRAL BASALFOREBRAIN CHOLINERGIC NEURONS MODULATE CONTEXTUALFEAR MEMORY
Yanrong Zheng, Zhong Chen

Overly strong fear memories can cause pathological conditions. Histamine H3 receptor(H3R) has been viewed as an optimal drug target for CNS disorders, but its role in fear
memory remains elusive. We find that a selective deficit of H3R in cholinergic neurons, but
not in glutamatergic neurons, enhances freezing level during contextual fear memory
retrieval without affecting cued memory. Consistently, genetically knocking down H3R or
chemogenetically activating cholinergic neurons in the ventral basal forebrain (vBF) mimics
this enhanced fear memory, whereas the freezing augmentation is rescued by re-expressing
H3R or chemogenetic inhibition of vBF cholinergic neurons. Spatiotemporal regulation of
H3R by a light-sensitive rhodopsin-H3R fusion protein suggests that postsynaptic H3Rs invBF cholinergic neurons, but not presynaptic H3Rs of cholinergic projections in the dorsal
hippocampus, are responsible for modulating contextual fear memory. Therefore, precise
modulation of H3R in a cell-type- and subcellular-location-specific manner should be
explored for pathological fear memory.

Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province,
College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou
310053, China.
*Correspondence to Zhong Chen (chenzhong@zju.edu.cn)

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINE

WHOLE BRAIN OUTPUT AND
HISTAMINERGIC NETWORK
W. Lin, Y. Wang, Z. Chen*INPUT

MAPPINGOF

MOUSEHistamine is a conserved neuromodulator in mammalian brains and critically involved inmany physiological functions. Understanding the precise structure of histaminergic output
and input network is the cornerstone in elucidating its function.
Herein, using novel HDC-CreERT2 mice and genetic labeling strategies, we reconstructed
whole brain 3D structure of histaminergic neurons and their output and input circuits at
0.32×0.32×2 μm3 pixel resolution with a cutting-edge fluorescence micro-optical sectioning
tomography system (fMOST).
Based on the data of whole-brain histaminergic output map, we quantified the fluorescencelabeled fiber density of all brain areas and found that histaminergic fiber density varied
significantly among brain regions. The density of histaminergic fiber was positively
correlated with the amount of histamine release induced by optogenetic stimulation or
physiological aversive stimulation. Moreover, we reconstructed fine morphological structureof 60 histaminergic neurons via sparse labeling, and uncovered the largely heterogeneous
projection pattern of individual histaminergic neuron. On the other hand, wo also analyzed
whole-brain input map of histaminergic neurons, and found that most upstream brain regions
located in the hypothalamus. Besides, some nuclei of thalamus, striatum, midbrain,hippocampus, pallidum, and cortical subplate also provide dense inputs to histaminergic
neurons. Interestingly, there are specific layer distribution of upstream cortical neurons, andtheir co-projection pattern was completely analyzed. Then, the excitatory and inhibitory
components of neurons in the main upstream brain regions were determined using in situ
hybridization staining. Lastly, we selected paraventricular nucleus of the thalamus (PVT), andlateral septal nucleus (LS) as representative of excitatory and inhibitory brain regions, whichshow differential electrophysiological functions to histaminergic neurons and dynamic
characteristics of neuronal activity in sleep-wake rhythm.
Collectively, this study reveals an unprecedented whole-brain quantitative analysis ofhistaminergic projections and upstream inputs at the mesoscopic and microscopic circuit level,
providing a foundation for shedding light on histamine’s role not only in physiologic function
but also CNS disorders.
*Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province,
School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China;
310053
Corresponding author: Prof. Chen Zhong. E-mail: chenzhong@zju.edu.cn

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINEHISTAMINE-4 RECEPTOR ANTAGONIST INHIBITS PRO-INFLAMMATORYMICROGLIA AND PREVENTS THE PROGRESSION OF PARKINSON-LIKE
PATHOLOGY: A NEW THERAPEUTIC STRATEGY
Qiuyuan Fang, Helena Xicoy, Junqing Shen, Sabina Luchetti, Di Dai, Pei Zhou, Xin-Rui Qi,
Gerard J.M. Martens, Inge Huitinga, Dick F Swaab, Chunqing Liu#, Ling Shan#

Activation of microglia is presumed to play a key role in the pathogenesis of Parkinson's disease (PD). The
activity of microglia is regulated by the histamine-4 receptor (H4R), thus providing a novel target that may
prevent the progression of PD. However, this putative mechanism has so far not been validated. In ourprevious study, we found that mRNA expression of H4R was upregulated in the basal ganglia of PD patients.
In the current study, upregulation of H4R-mRNA, stands out by robustness and consistency in an
independent genome-wide RNA sequencing study of basal ganglia of PD post-mortem brains. We validated
this possible mechanism using the rotenone-induced PD rat model, in which mRNA expression levels of
H4R-, and microglial markers were significantly increased in the substantia nigra pars compacta (SNpc).
Inhibition of H4R in rotenone-induced PD rat model by infusion of the specific H4R antagonist JNJ7777120(JNJ) into the lateral ventricle resulted in blockade of microglial activation. In addition, pharmacologicaltargeting of H4R in rotenone-lesioned rats resulted in reduced apomorphine-induced rotational behaviour
and prevention of dopaminergic neuron degeneration and associated decreases in striatal dopamine levels.
These changes were accompanied by a reduction of Lewy body-like neuropathology in both SNpc andstriatum. Moreover, other neurotransmitters including γ-aminobutyric acid, glutamine, serotonin wererelatively stable under the JNJ treatment. Our results provide first proof of the efficacy of an H4R antagonist
in a PD rat model, and proposes the H4R as a promising target to clinically tackle microglial activation andthereby the progression of PD.

Ling Shan PhD: Netherlands Institute for Neuroscience, KNAW, Meibergdreef 47 1105 BA Amsterdam, theNetherlands. Email: l.shan@nin.knaw.nl

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINEHISTAMINE H2 RECEPTOR DEFICIENCY IN PARVALBUMIN-POSITIVE NEURONSLEADS TO ATTENTION DEFICIT HYPERACTIVITY DISORDER-LIKE
PHENOTYPES
D. An, Y, You, Q. Ma, R. Liao, H. Chen, Y. Wang, Y. Wang, H. Dai, H. Li, L. Jiang, Z.Chen *, W. Hu*
Attention deficit hyperactivity disorder (ADHD) is a behavioral disorder with a prevalence of 4%,
characterized by symptoms of inattention, hyperactivity, and impulsivity. Currently, the neurophysiologicalmechanism underlying ADHD remains unclear. Moreover, first-line drug treatments for ADHD areassociated with serious side effects due to their nonspecific effects and the presence of inverted-U-shaped
dose-effect curves. Here, we discovered that deficiency of histamine H2R in parvalbumin-positive (PV+)
neurons induce ADHD-like phenotypes, including hyperactivity, impulsivity, and inattention. Selective
knockdown of H2R in PV+ neurons in the substantia nigra pars recticulata (SNr), but not in medial prefrontal
cortex, resulted in ADHD-like behavioral disorders by attenuating PV+ neuronal activity. However, H2R
overexpression in SNr did not affect locomotion or attention. We observed decreased H2R expression in
SNr PV+ neurons in dopamine transporter (DAT)-deficient mice, an animal model for ADHD and their
behavioral phenotypes were relieved by treatment with an H2R agonist. Our findings also reveal that H2R
deficiency in PV+ neurons induces dysfunction of neuronal efferents from SNr PV+ neurons to thesubstantia nigra pars compacta (SNc) dopaminergic neurons, contributing only to impaired attention. In
addition, efferents from SNr PV+ neurons to intermediate layer of superior colliculus (mSC) contribute toboth hyperactivity and inattention. Collectively, these results demonstrate that H2R deficiency in PV+
neurons plays a critical role in the pathogenesis of ADHD by dampening the activity of SNr PV+ neurons
and involves different efferents. These findings pinpoint the critical cell type, brain region, and neuralcircuits through which H2R participates in the pathogenesis of ADHD, which enhances our understandingof the molecular basis of ADHD and identifies H2R in SNr PV+ neurons as a precise therapeutic target in
ADHD.

Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of
Pharmaceutical Sciences, Zhejiang Chinese Medical University, No. 548 Binwen Road, Hangzhou 310053,
China
School of Basic Medical Sciences, Zhejiang University School of Medicine, No. 866 Yuhangtang Road,
Hangzhou 310058, China
Correspondence: Huww@zju.edu.cn, chenzhong@zju.edu.cn

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINEEFFECTS OF H3R ANTAGONIST E169 ON AUTOPHAGY AND AUTISM-LIKE
BEHAVIORAL PHENOTYPES IN BTBR MOUSE MODEL OF AUTISM
N. Eissa*, P. Jayaprakash, Dorota Łazewska, Katarzyna Kieć-Kononowicz, B. Sadek*
Accumulation of evidence suggests that autophagy is involved in the pathogenesis of autism spectrum
disorder (ASD). Akt-mTOR pathway is an important signaling cascade associated with long-term plasticity
and thus may contribute to memory and cognitive dysfunction, suggesting its dysregulation in ASD. In
addition, mTOR has been widely implicated in autophagy activation, which is one of the important
autophagy induction regulators. It is suggested that H3R blockade may be neuroprotective in ASD, as
autophagy is reported to be impaired in ASD. Hence, the effects of acute treatment with the novel H3R
antagonist E169 (2.5, 5, and 10 mg/kg, i.p.) on short-term memory (STM), long-term memory (LTM), andanxiety levels in male BTBR mice were evaluated using Novel object recognition test (NORT) and open
field locomotor test (OFLT) tests. E169 (2.5 mg/kg, i.p) provided significant memory-improving effects on
BTBR STM and LTM impairments in NORT.
E169 (2.5 mg/kg, i.p)-provided effects were comparable to those observed with the reference mTOR
inhibitor rapamycin and was abrogated with the CNS-penetrant H3R agonist (R)-α-methylhistamine. Our
results demonstrated that E169 ameliorated BTBR memory deficits by antagonism of H3Rs and modulationof the disturbed expression of Akt, mTOR, and LC-3 proteins, signifying that E169 regulated the Akt-mTOR
signaling pathway in the cerebellum of tested mice. The results revealed that E169 (2.5 mg/kg, i.p.) restored
the abnormal anxiety and hyperactivity observed in OFLT.
These findings indicate that H3R antagonists like E169, which possess favorable in silico physicochemical
characteristics and maintain crucial interactions in docking studies at H3R, could play a role insimultaneously regulating disrupted brain neurotransmitters and the dysregulated Akt-mTOR signaling
pathway associated with autophagy in neurological diseases. This may add a new therapeutic management
strategy for memory and cognitive impairment-associated disorders including ASD.

*Abu Dhabi University, Department of Biomedical Sciences, College of Health Sciences, Abu Dhabi P.O.
Box 59911, UAE.
*United Arab Emirates University, Department of Pharmacology and Therapeutics, College of Medicine &Health Sciences, Al Ain P.O. Box 15551, UAE.
*E-mails corresponding authors: nermin.eissa@adu.ac.ae & bassem.sadek@uaeu.ac.ae

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINETHE H3R ANTAGONIST E159 ATTENUATES NEUROINFLAMMATION AND
AUTISTIC-LIKE BEHAVIOURS IN BTBR T+ tf/J MOUSE MODEL OF AUTISM
Shilu Deepa Thomas, P. Jayaprakash, Dorota Łazewska, Katarzyna Kieć-Kononowicz, B. Sadek*

Large body of evidence suggests the involvement of cognitive impairment, increased levels of inflammationand oxidative stress in the pathogenesis in autism spectrum disorder (ASD). ASD commonly coexists withpsychiatric conditions like anxiety and cognitive challenges, and individuals with ASD exhibit significant
levels of inflammation and immune system dysregulation. Studies have identified elevated levels of proinflammatory markers such as IL-1β, IL-6, IL-2 and TNF-α, particularly in young children with ASD. The
current therapeutic options for ASD show limited effectiveness, signifying the importance of exploringnovel and efficient drugs to address the core symptoms. The role of histamine H3 receptors (H3Rs) inmemory and the prospective role of H3R antagonists in pharmacological control of neurodegenerative
disorders, e.g., ASD is well-accepted. Hence, the effects of chronic systemic administration of H3R
antagonist E159 and on autistic-like repetitive behaviors, social deficits, memory and anxiety parameters aswell as neuroinflammation in Black and Tan BRachyury (BTBR) mice were evaluated using Y maze, Barnes
maze, self-grooming, open field and three chamber social test. E159 (2.5, 5 and 10 mg/kg, i.p.) dosedependently ameliorated repetitive and compulsive behaviors by reducing the increased time spent in selfgrooming and improved reduced spontaneous alternation in BTBR mice. Moreover, treatment with E159
attenuated disturbed anxiety levels and social deficits in tested male BTBR mice. Furthermore, E159
attenuated oxidative stress by significantly increasing GSH, CAT, and SOD, and decreasing the increased
levels of MDA in the cerebellum as well as the hippocampus. In addition, E159 decreased the elevated levelsof proinflammatory cytokines (tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and IL-6). The
observed results show that H3R antagonists like E159 may represent a promising novel pharmacologicalstrategy for the future treatment of ASD.
*United Arab Emirates University, Department of Pharmacology and Therapeutics, College of Medicine &Health Sciences, Al Ain P.O. Box 15551, UAE.
*E-mails corresponding authors: bassem.sadek@uaeu.ac.ae

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINEAN H2R-DEPENDENT MEDIAL SEPTUM HISTAMINERGIC CIRCUIT MEDIATESFEEDING BEHAVIOR
L. Xu, W. Lin, Y. Zheng, J. Chen, Z. Fang, N. Tan, W. Hu, Y. Guo, Y. Wang and Z. Chen*
Novel targets for treating feeding-related diseases are of great importance, and histamine has long been
considered an anorexigenic agent. However, understanding its functions in feeding in a circuit-specific way
is still limited. Here, we report a medial septum (MS)-projecting histaminergic circuit mediating feeding
behavior. This MS-projecting histaminergic circuit is functionally inhibited during food consumption, andbidirectionally modulates feeding behavior via downstream H2, but not H1, receptors on MS glutamatergic
neurons. Further, we observed a pathological decrease of histamine 2 receptors (H2Rs) expression in MS
glutamatergic neurons in diet-induced obesity (DIO) mice. Genetically, down-regulation of H2Rs
expression in MS glutamatergic neurons accelerates body-weight gain. Importantly, chronic activation of
H2Rs in MS glutamatergic neurons (with its clinical agonist amthamine) significantly slowed down thebody-weight gain in DIO mice, providing a possible clinical utility to treat obesity. Together, our results
demonstrate that this MS-projecting histaminergic circuit is critically involved in feeding, and H2Rs in MS
glutamatergic neurons is a promising target for treating body-weight problems.

*Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Schoolof Pharmaceutical Sciences, Zhejiang Chinese Medical University, No. 548 Binwen Road,
Hangzhou 310053, China
Correspondence: chenzhong@zju.edu.cn

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION II – NEURONAL HISTAMINEHISTAMINE RECEPTORS: NOVEL DRUG TARGETS FOR SCHIZOPHRENIA
Qianyi Ma, Li Cheng, Lei Jiang, Zhong Chen, Weiwei HU
Schizophrenia is a serious mental disorder, and existing antipsychotic drugs show limited efficacy and cause
unwanted side effects, that could be due to non-precise targeting. Histamine in the brain is a neurotransmitter
involved in many pathophysiological processes including waking-sleeping, food intake, learning, andmemory, and it primarily functions through the histamine H1 receptor (H1R). Although H2 receptors (H2Rs)
are also widespread in the brain, their functions are not well understood. By Cre-loxp system, chemogenetic
approach, electrophysiology and human brain samples, we found that H1R deficiency in basal forebrain
cholinergic neurons is critical for schizophrenia-like negative symptoms, however, the H1R deficiency indopaminergic neurons and glutamatergic neurons did not induce such behavioral disorder. Interestingly, theH2R deficiency in the prefrontal cortex glutamatergic neurons is critical for behaviors resembling both
negative and both symptoms in schizophrenia through a downregulation of neuronal firing by modulating
HCN currents. H2R agonists can be used to treat schizophrenia-like phenotypes in an MK-801-induced
mouse model of schizophrenia. These studies provide histamine receptors as novel drug targets forschizophrenia and also established the histamine receptor hypothesis for the pathogenesis of schizophrenia
and improve the understanding of the functional role of H2R in the brain, especially in glutamatergic
neurons.
Department of Pharmacology and Department of Pharmacy of the Second Aﬃliated Hospital, Zhejiang
University School of Medicine, Hangzhou, 310058, China.

Weiwei Hu, Ph.D., Professor, Zhejiang University, Hangzhou, 310058, China,
email address: huww@zju.edu.cn.

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION III – HISTAMINE, MAST CELLS & BASOPHILSORAL DESENSITIZATION TO PEANUT DIFFERENTIALLY AFFECTS THE
REACTIVITY OF HUMAN BASOPHILS TO IgE-DEPENDENT STIMULATION
B.F. Gibbs, M.H. Shamji, N. Patel, P.J. TurnerBasophils are likely to play a key role in determining the severity of allergic reactions, including
anaphylactic shock, through the rapid release of histamine and lipid mediators upon allergenmediated activation. Allergen immunotherapy is very successful in preventing basophil
degranulation for venom and drug-induced reactions, but less straightforward for peanut allergy
and associated with significant adverse events including anaphylaxis. To overcome this, we used
an immunotherapy protocol with initial updosing using boiled rather than roasted peanuts toachieve desensitization. Our aims were to observe whether this approach reduces peanut allergeninduced histamine release from basophils obtained from seven children with severe peanut allergy(NHS HRA approval reference 15/LO/0287). Basophils were purified from peripheral blood using
negative immunomagnetic selection before incubation in the presence or absence of peanut
allergen, anti-IgE or fMLP. Histamine release was assessed by spectrofluorometric autoanalysis. In
five donors, immunotherapy resulted in a striking reduction in basophil histamine release to peanut
allergen after 1 year of immunotherapy (from 41.7±8% to 13.5±6.3%). Anti-IgE-dependentbasophil reactivity was also moderately reduced in these five donors following allergen
immunotherapy (from 43.1±10% to 31.6±11.8%), but not fMLP. In contrast, immunotherapy failed
to reduce either peanut allergen- or anti-IgE-induced histamine release in two donors which also
displayed the highest histamine release (>65%) to peanut before immunotherapy. These
investigations highlight that a population of high basophil responders are resistant to initial allergen
immunotherapy, underlining the need for new therapeutic strategies which target signalling
pathways responsible for hyperreactive basophils.
Canterbury Christ Church University, Canterbury, CT1 1QU, UK
Email: bernhard.gibbs@canterbury.ac.uk

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION III – HISTAMINE, MAST CELLS & BASOPHILSGPR35 MEDIATES STABILIZATION OF MAST CELLS
M. Oka, S. Akaki, O. Ohno, M. Terasaki, Y. Hamaoka-Tamura, M. Saito, S. Kato, A. Inoue, J.
Aoki, K. Matsuno, K. Furuta, S. Tanaka
Background: Mast cell stabilizers including sodium cromoglycate have been used as useful anti-allergic
drugs, although their molecular targets remain to be determined. Recent studies demonstrated that they could
act on GPR35, an orphan G protein-coupled receptor, as the agonists. We investigated whether GPR35 was
expressed in mast cells and clarified how GPR35 suppresses degranulation of mast cells.
Methods: We used rat purified peritoneal mast cells, and murine IL-3-dependent bone marrow-derived
cultured mast cells (BMMCs) as mast cell models. Because GPR35 was absent in a rat basophilic mast cellline, RBL-2H3, we prepared a cloned cell line constitutively expressing rat GPR35 cDNA (RBL-2H3/HArat GPR35). IgE-dependent immediate responses were assessed by the passive cutaneous anaphylaxis (PCA)
model.
Results: Previously reported GPR35 agonists and newly developed agonists suppressed degranulation of rat
peritoneal mast cells upon IgE-mediated antigen stimulation. Decreased levels of degranulation were foundin RBL-2H3/HA-rat GPR35 when it was stimulated by IgE/Ag stimulation whereas no significant changes
were observed when they were activated by thapsigargin. A GPR35 agonist, zaprinast, induced transient
activation of RhoA and a transient decrease in the amount of filamentous actin. No significant changes wereobserved in PCA responses in the GPR35-deficient mice whereas therapeutic effects of the GPR35 agonists,such as disodium cromoglycate, were abrogated in the GPR35-deficient mice.
Conclusions: GPR35 expressed in rat and mouse mast cells mediates suppression of degranulation inducedby IgE-mediated antigen stimulation. GPR35-mediated RhoA activation may be involved in the suppressionof mast cell degranulation through cortical actin reorganization.

Laboratory of Pharmacology, Kyoto Pharmaceu4cal University, Kyoto 607-8414, Japantanaka-s@mb.kyoto-phu.ac.jp

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION III – HISTAMINE, MAST CELLS & BASOPHILS
MAST CELLS ARE DIFFERENTLY AFFECTED BY ST-2309 AND CIPROXIFAN, H3R
BLOCKERSA Walczak-Drzewiecka, WA Fogel, H Stark, J Dastych

The current approach in treating neurodegenerative diseases involves the use of multitarget drugs
that contain various groups capable of counteracting different aspects of the disease's pathology.
Multitargeting drug candidates being thoroughly explored are these containing the histamine H3
receptor antagonist/inverse agonist, as the core of their chemical structure. An example is peptidelike
ST-2309 (3,6-bis(4-(3-(piperidin-1-yl)propoxy)benzyl)piperazine-2,5-dione). All
neurodegenerative diseases are characterized by neuroinflammation. There is a shred of growing
evidence suggesting that the activation of microglia cells and astrocytes as well as the permeabilityof the blood-brain barrier are triggered by the activated mast cells (MC) and their released
meditators.
The effect of ST-2309 on mast cells and its comparison with that of ciproxifan, an H3R antagonist,
was investigated.
The human MC line LAD2, was a gift from Dr. A. S. Kirshenbaum (NIH, Bethesda, MD). Cells
were incubated at 37 °C in 5% CO2 in a culture medium, at density of 500,000 cells/mL, in thepresence of ST-2309 or Ciproxifan for 20 h. Aliquots of isolated total RNA were reversetranscribed using the Maxima First Strand cDNA Synthesis Kit for RT-qPCR (Thermo Fisher
Scientific) in the presence of oligo-dT18 primers. The levels of specific gene expression were
measured by real-time PCR amplification. The relative gene expression was calculated using ΔΔC
T method with the geometric mean of selected reference genes.
ST-2309 treated LAD2 mast cells showed a significant increase in gene expression of cytokines
IL9, IL10 and TNF-α at 20 µM, in contrast to ciproxifan treated cells, which showed a significant
reduction in gene expression of IL1A and IL16 at 0.1 µM, and additionally of IL10, TGFB and
CMA1 at 10 µM. It is proposed that activation of proinflammatory cytokine genes expression isrelated to other than H3R blocking moiety of the multitarget compound.

Laboratory of Cellular Immunology, Institute of Medical Biology, Polish Academy of Sciences,
Tylna 3A, 90-364 Lodz, Poland
email address of the corresponding author: wafogel@cbm.pan.plORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION III – HISTAMINE, MAST CELLS & BASOPHILSSCABIES MITES, WHAT'S ITCHING - DOES THE INTERPLAY BETWEEN PARASITEDERIVED PRURITOGENS AND HOST MRGPRX2 EXPLAIN THE INTENSE ITCHINGIN HUMAN SCABIES?
Franco H. Falcone, Prema S. Prakash, Michael H. W. Weber, Bernardo P. Moreira
The most salient feature of scabies, caused by Sarcoptes scabiei, is its intense itch, which is poorly
responsive to anti-histamine treatment. Use of acaricides leads to week-long post-treatment itchexacerbation. We demonstrate how a Sarcoptes scabiei-derived protein and its derived peptides canactivate human Mas-related G-protein coupled receptor member X2 (MRGPRX2).
Sarcoptes scabiei–derived Ss-14 was recombinantly expressed in Sf21 insect cells in serum-free
medium, purified by affinity chromatography and tested for activation of a fluorescent RBL reporter
cell line stably transfected with MRGPRX2.
Ss-14 and derived Lysine/Glutamic acid-rich peptides induced fast degranulation of MRGPRX2
reporter cells in nanomolar concentration. DeepLearning-based in silico structure prediction using
the AlphaFold2 multimer approach was used to model tight binding of Ss-14-derived peptides to theligand binding pocket.
This is the first report of a parasite-derived molecule activating MRGPRX2 in the nanomolar range,highlighting MRGPRX2 as a promising novel target for prevention of post-treatment itchexacerbation in human scabies.
Institute of Parasitology, Justus Liebig University Giessen, Giessen, Germany
franco.falcone@vetmed.uni-giessen.deORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION IV – DRUG DESIGN & MOLECULAR TARGETINGSTRUCTURAL BASIS OF AGONIST RECOGNITION AT THE H4 RECEPTOR
R Leurs, R Xia, S Shi, Zh Xu, H F Vischer, A D Windhorst, Y Qian, Y Duan, J Liang, K Chen, A
Zhang, C GuoandYHe

The histamine H4 receptor (H4R) plays key role in immune cell function and is a highly valued target
for treating allergic and inflammatory diseases. However, structural information of H4R remains
elusive. Here, we report four cryo-EM structures of H4R/Gi complexes, with either histamine or
small molecule agonists clobenpropit, VUF6884 and clozapine bound. Combined withmutagenesis, ligand binding and functional assays, the structural data reveal a distinct ligand
binding mode where D943.32 and a π-π network determine the orientation of the positively
charged group of ligands, while E1825.46, located at the opposite end of the ligand binding pocket,
plays a key role in regulating receptor activity. The structural insight into H4R ligand binding allows
us to identify mutants at E1825.46 for which the agonist clobenpropit acts as an inverse agonist
and to correctly predict inverse agonism of a closely related analogue with nanomolar potency.
Together with the findings regarding receptor activation and Gi engagement, we established aframework for understanding H4R signaling and provide a rational basis for designing novelantihistamines targeting H4R.
.
Department of Medicinal Chemistry, Amsterdam Ins$tute of Molecular Life Sciences, Faculty of Science,
Vrije Universiteit Amsterdam, 1081 HZ, The Netherlands
r.leurs@vu.nl

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION IV – DRUG DESIGN & MOLECULAR TARGETING
PHARMACOLOGICAL CHARACTERIZATION OF SEVEN HUMAN HISTAMINE H3
RECEPTOR ISOFORMS
Meichun Gao, Mabel E. Dekker, Rob Leurs and Henry F. Vischer

The histamine H3 receptor (H3R) regulates as a presynaptic G protein-coupled receptor the release ofhistamine and other neurotransmitters in the brain, and is consequently a potential therapeutic target forneuronal disorders. The human H3R encodes for seven splice variants that vary in the length of intracellularloop 3 and/or the C-terminal tail but are all able to induce heterotrimeric Gi protein signaling. The last two
decades, H3R drug discovery and lead optimization has been exclusively focused on the 445 amino acidslong reference isoform H3R- 445.
In this study, we pharmacologically characterized for the first time all seven H3R isoforms by determining
their binding affinities for reference histamine H3 receptor agonists and inverse agonists. The H3R-453, H3R415, and H3R-413 isoforms display similar binding affinities for all ligands as the H3R-445. However,increased agonist binding affinities were observed for the three shorter isoforms H3R-329, H3R-365, andH3R-373, whereas inverse agonists such as the approved anti-narcolepsy drug pitolisant (Wakix®) displayed
significantly decreased binding affinities for the latter two isoforms. This opposite change in binding affinityof agonist versus inverse agonists on H3R-365 and H3R-373 is associated with their higher constitutive
activity in a cAMP biosensor assay as compared to the other 5 isoforms. The observed differences inpharmacology between longer and shorter H3R isoforms should be considered in future drug discovery
programs.
Department of Medicinal Chemistry, Amsterdam Ins8tute of Molecular Life Sciences, Faculty of Science,
Vrije Universiteit Amsterdam, 1081 HZ, The Netherlands
r.leurs@vu.nl

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION IV – DRUG DESIGN & MOLECULAR TARGETINGDISTINCT G PROTEIN AND β -ARRESTIN RECRUITMENT TO SEVEN HISTAMINE
H3 RECEPTOR ISOFORMS
Meichun Gao, Jasper F. Ooms, Rob Leurs and Henry F. Vischer
The histamine H3 receptor (H3R) is a presynaptic G protein-coupled receptor (GPCR) that plays a pivotal
role in regulating the release of histamine and other neurotransmitters in the brain, making it a potential
target for therapeutic interventions in neuronal disorders. The human H3R gene encodes seven splicevariants that conserve the seven transmembrane helical domains but vary in the length of intracellular loop
3 (ICL3) and/or the C-terminal tail. Despite that the ICL3/C tail of GPCR is important for G protein/Arrestin
coupling, the comprehensive signaling transduction and functionality of these H3R isoforms remain elusive.
To address this gap, we developed G protein and β-arrestin recruitment assays to assess the interaction ofactivated H3R isoforms with their respective downstream effectors in real time by NanoBiT complementary
technology. We found the H3R-453, H3R-415, and H3R-413 isoforms were capable of recruiting the miniGi protein in a similar way as the canonical isoform H3R-445 upon 10 µM histamine stimulation. Whereas
the low amplitude response from the H3R-373, H3R-365 and H3R-329 isoforms was related to their highconstitutive activity. β-arrestin 2/1 recruitment to H3R-445, H3R-415, and H3R-413 isoforms exhibited asustained signal over time upon histamine stimulation, whereas H3R-365 and H3R-329 isoforms displayed
a transient kinetical profile. However, H3R-453 and H3R-373 showed no β-arrestin2/1 recruitment upon
histamine stimulation. In conclusion, our findings contribute to a more comprehensive understanding of
H3R and its isoform signaling. The insights may shed light on their potential roles as presynaptic receptors
in modulating neurotransmitter release and neuronal function.
Department of Medicinal Chemistry, Amsterdam Ins8tute of Molecular Life Sciences, Faculty of Science,
Vrije Universiteit Amsterdam, 1081 HZ, The Netherlands
r.leurs@vu.nl

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION IV – DRUG DESIGN & MOLECULAR TARGETINGREACHING BEYOND THE UV SPECTRUM – A PHARMACOLOGICAL PROFILE OF
A RED-SHIFTED H1R PHOTOCAGED LIGAND
Ivana Josimovic, Yang Zheng, Maikel Wijtmans, Henry Vischer, Rob Leurs
Photopharmacological modulation of GPCRs offers new ways to modify on-target activity of ligands in a spatiotemportal manner. One approach involves the introduction of a photosensitive moiety to a pharmacologically
active compound, hereby blocking its activity (photocaging). The active compound can then be irreversibly
uncaged with light. However, many available caged photoligands rely on UV light for uncaging, which can bedamaging for in vitro and in vivo systems. Longer wavelengths are lower in energy and therefore provide better
tissue penetration, hereby opening doors for more efficient real-time photo-modulation of ligand activity, while
being less invasive for the system. We designed and synthetized an infrared-shifted photocaged histamine H1R
antagonist, VUF25549. The compound has more than 50 times lower H1R affinity than its uncaged counterpartand has little to no activity in GPCR signalling assays. It can be uncaged in live-cell confocal imaging assays.
Our research shows not only that H1R antagonist photoligand activity can be modulated by light, but also
highlights the potential of real-time on-target activity modulation of H1R by light in living cells.
Department of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems(AIMMS), Vrije Universiteit Amsterdam, Amsterdam, 1081HZ The Netherlands.
i.josimovic@vu.nl

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION IV – DRUG DESIGN & MOLECULAR TARGETINGTETRAZINE-BASED BUILDING BLOCKS FOR CLICK CHEMISTRY ON
HISTAMINE H3 RECEPTOR LIGANDS
M. Stark, L. Leitzbach, H. Stark
Structural diversity in histamine H3 receptor (H3R) antagonists has dramatically increased within the lasttwo decades. Nevertheless, Pitolisant stands out as a widely recognized reference compound, beeing theonly approved H3R antagonist drug for sleep-related diseases. Increasing knowledge on thepharmacological profile as well as on potential therapeutic effects gave fresh impetus to multitargeting
ligands for potentially improved therapy. The H3R pharmacophore on non-imidazole compounds can be
combined in different ways with additional pharmacophoric elements while maintaining its H3R affinity.
Click chemistry has been a versatile technique to combine different chemical motifs in an efficient way.
Despite the widespread use of azide-alkyne 1,3-diploar cycloaddition, we have employed tetrazine-based
compound development to new approaches for H3R ligands and easy chemical combinations. Notably, tothe best of our knowledge, no H3R ligands are currently known to have the capability to engage in metalfree Click chemistry reactions, rendering them intriguing for in vivo applications. Here, we introduce thesynthesis and biological evaluation of innovative ligands for the H3R featuring a methyl tetrazine moiety,designed to function as one partner of building blocks for Click chemistry. These novel compounds arecharacterized by a piperidinoalkyl unit connected to a para-substituted phenol. The tetrazine building block,effective for the inverse electron-demand Diels-Alder (IEDDA) Click reaction, is attached directly at thepara-position or via alkyl phenol ethers with diverse aliphatic chain lengths. Throughout the course ofsynthesis, we also obtained and isolated the corresponding methyl dihydrotetrazines, subsequently
subjecting them to H3R affinity testing. The radioactive displacement assay on H3R showed that allcompounds featured Ki values in the lower nanomolar concentration range. This work presents a small seriesof novel H3R ligands exhibiting good H3R affinity and versatile capability to Click chemistry reactions via
IEDDA for different building blocks with ring-strained dienophiles across various in vitro and in vivo
applications in bioorthogonal applications for increased structural and functional diversity.
Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf,
Universitaetsstr. 1, 40225 Duesseldorf, Germany
stark@hhu.de

ORAL PRESENTATIONS ABSTRACTYOUNG INVESTIGATORS AWARDSHISTAMINE RECEPTOR H4 MODULATES THE EXPRESSION OF Na+/H+ (NHE)3
exchanger IN THE RENAL PROXIMAL TUBULAR CELL LINE HK-2
C. Gerbino, F. Foglietta, E. Benetti, AC. Rosa

In the proximal tubule, the 50% of sodium reabsorption is achieved by the Na+/H+ (NHE)3 exchanger. It
plays a crucial role in the regulation of sodium and fluid balance, blood pressure homeostasis, andpathophysiology of hypertension. Moreover, NHE3 expression is dramatically increase in diabetic
nephropathy and contributes to albuminuria. In a murine model of diabetic nephropathy, the histamine H4
receptor antagonist JNJ39758979 prevented the oversexpression-induced of NHE3.
The aim of this study is to investigate whether histamine directly affect the functional expression of NHE3
in HK-2 cells, an in vitro model of renal proximal tubule.
Cells were exposed to histamine 0-1000nM for 0-48h and NHE3 gene and protein expression were evaluatedby qPCR and Western blot. The activity of NHE3 was measured as intracellular pH (ipH) recovery after
NH4Cl loading by the BCECF-AM-based method. The receptor antagonists chlorpheniramine 10μM and
JNJ7777,120 1μM were used to dissect the specific receptor contribute. The involvement of MAPK as
signaling pathway downstream was also assessed.
Exposure to histamine induced a concentration-dependent NHE3 gene and protein transcription with a peakat 100nM from 16h followed by protein translation after 48h. Consistently at 48h histamine reduced the ipH
recovery time, suggestive of an increased NHE3 activity. JNJ7777120 blunted both the activation and theexpression of NHE3, while chlorpheniramine was effective only on NHE3 activity. Similar effects for
histamine100nM were observed already at 60 min. The functional and the transcriptional effects wereredundantly mediated by p38 and p42/44.
In conclusion histamine activating both H1 and H4 receptor regulates NHE3 activity in the proximal tubulewith both early (60min) and late (48h) effects. These results strengthen the hypothesis of histamine as atarget in kidney diseases where NHE3 could have a crucial role
Department of Scienza e Tecnologia del Farmaco, University of Turin (Turin, 10124, Italy)
chiara.gerbino@unito.it

ORAL PRESENTATIONS ABSTRACTYOUNG INVESTIGATORS AWARDSMULTITARGETING COMPOUNDS FOR NEURODEGENERATIVE DISEASES: DUAL
H3R/ChEs LIGANDS WITH CHELATING PROPERTIES
F.B. Lopes, T. Werner, I.A. Bagatin, H. Stark, J.P.S. Fernandes

The strategy for addressing multiple targets simultaneously stands as an advancement in the treatment ofmultifactorial diseases, such as neurodegenerative diseases, in which the progressive neuronal death leads
to several dysfunctions, including the cognitive decline. The role of metal ion-catalyzed oxidative stress inthe neuronal death is well established, as well as the involvement of acetylcholine and histamine on
cognition.
Thus, the modulation of targets related to histaminergic and cholinergic neurotransmission, along with theantioxidant properties of chelating agents, may be an alternative in the treatment of these conditions. In thiswork, our aim was to synthesize and evaluate a set of compounds (LINS05d) combining histamine H3
receptor (H3R) antagonist, cholinesterases (ChEs) inhibitor and chelating properties in one molecule. The
compounds were designed by overlapping structural features required for binding at H3R and ChEs, also
containing ion chelating groups. Eighteen compounds were obtained with satisfactory yields, which were
tested in anti-AChE/BChE assays. Their affinities at the H3R were assessed by binding assays and thechelating properties were evaluated spectrophotometrically using Fe2+/3+, Cu2+ and Zn2+. Compounds 613,
313 and 433 were the most potent anti-ChEs in the series (pIC50 4.4-4.9), while compounds 413, 414 and616 presented the highest affinity values for H3R (pKi 6.4-6.5). Isoquinoline and quinoline moieties led tohigher affinity at H3R, while the benzylpiperazine motif mostly contributed to the anti-ChE activity. The
best chelating activity was obtained with isoquinoline derivatives. From the multitarget perspective,
compounds 413 and 433 can be highlighted as the most promising. This study suggests that isoquinoline
and benzylpiperazine moieties can provide the most interesting dual H3R/ChE activity with chelating
properties. The compounds herein reported represent interesting multitargeting prototypes for further
studies.
Department of Pharmaceutical Sciences, Federal University of São Paulo, Diadema-SP, Brazil
e-mail: joao.fernandes@unifesp.brORAL PRESENTATIONS ABSTRACTYOUNG INVESTIGATORS AWARDSVUF26063: A SECOND-GENERATION PHOTOSWITCHABLE LIGAND TO
OPTICALLY CONTROL THE HISTAMINE H3 RECEPTOR
Ivana Josimovic, Lars Binkhorst, Icaro Simon, Bas de Boer, Barbara Zarzycka, Iwan de Esch,
Maikel Wijtmans, Henry Vischer, Rob Leurs
Photopharmacology uses light-sensitive ligands as tools to yield spatiotemporal control of protein activity andhas been emerging in recent years in the field of G protein-coupled receptors (GPCRs). The histamine H3 receptor(H3R) is highly expressed in the central nervous system and has been identified as a potential target in diseases
such as obesity, narcolepsy, Alzheimer’s, and ADHD. Previously, our group published the first generation ofazobenzene-based photoswitchable H3R antagonists. In this research, we aimed to improve their photochemical
properties by replacing the classical azobenzene with an arylazopyrazole photoswitchable moiety. Compared to
first generation H3R antagonists, key compound VUF26063 shows improved switching of 93% fromphotostationary state (PSS) PSScis to PSStrans using a less damaging wavelength of 500 nm, instead of UV lightat 430 nm. Improvements of pharmacological parameters include a nanomolar H3R affinity (pKi) for
VUF26063trans and a ~50 fold affinity difference between isomers. In addition, arylazopyrazole-based H3R
antagonists show a ~13 fold inhibitory potency (pIC50) difference between VUF26063 isomers in a histamineinduced PKA functional assay in HEK293T cells. Furthermore, VUF26063 can be repeatedly switched back andforward between isomers in situ within this assay.
Department of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS),
Vrije Universiteit Amsterdam, Amsterdam, 1081HZ The Netherlands.
i.josimovic@vu.nl

ORAL PRESENTATIONS ABSTRACTYOUNG INVESTIGATORS AWARDS
DO HISTAMINERGIC NEURONS EXPRESS ADENOSINE 1 RECEPTORS?
COMPARATIVE ANALYSIS WITH REFERENCE TO HIPPOCAMPAL DENTATE
GYRUS GRANULAR CELLS
Lea Wegmann, Helmut L. Haas, Olga A. Sergeeva

Adenosine, the degradation product of ATP, is a sleep pressure factor playing an important role inhomeostatic behavioral state control. The adenosine 1 receptor (A1R) is most sensitive to adenosine andreports sleep need to our brain. Controversial data were published during the last 18 years regarding
hypothalamic histaminergic neurons (HN) controlling wakefulness. Recent reviews describe a particularrole of HN in the action of adenosine, whereas we have not seen responses to adenosine in 13 rat HN in
2006. We analyzed single cell whole-transciptome data published recently and did not find A1R in any HNdata bases.“Hipposeq" reported that among adenosine receptors only A1R is expressed by hippocampal
dentate gyrus granular cells (DGgc) which can be identified by the expression of PDZd2. We selected thesecells as positive control. We performed in parallel electrophysiology and PCR to identify HN and DGgc, tostudy responses to adenosine and expression of A1R in mouse brain slices. Quantitative PCR showed thathippocampus of adult mice expresses 6 times higher level of A1R compared to the posterior hypothalamus.
In 70% of DGgc cells A1R was detected with single cell RT-PCR, whereas none of HN were A1R positive.
In patch-clamp experiments one HN out of 22 (17 mice) was inhibited by adenosine in a DPCPX (A1R
antagonist)-sensitive fashion, whereas 14 out of 16 DGgc were identified as A1R-positive by theirpharmacology (FEPT p<0.0001). In primary dissociated cell cultures of hippocampus, inhibition of firing
rate by adenosine was significantly stronger than in cultures made of posterior hypothalamus (MWT,
p<0.001). We conclude that the vast majority of HN during waking (when these cells are firing) do not sense
adenosine. This represents an important advantage for the allostatic regulation of waking: to sleep in theright time and place and to be awake as long as necessary during the fight or flight response.
(1) Institute of Neural and Sensory Physiology, Medical Faculty and University Hospital, Heinrich-HeineUniversity, Düsseldorf, 40225, Germany(2) Institute of Clinical Neurosciences and Medical Psychology, Medical Faculty and University Hospital,
Heinrich-Heine-University, Düsseldorf, 40225, Germany
Lea.Wegmann@hhu.de

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION V IN MEMORY OF PROF. PIER F. MANNAIONI –HISTAMINE IN THE HEART & THE KIDNEY
HALOPERIDOL, CLOZAPINE AND MIRTAZAPINE ARE FUNCTIONALANTAGONISTS AT HISTAMINE RECEPTORS IN HUMAN ATRIAL PREPARATIONS
J.M.A. Schlicht, B. Hofmann, U Gergs, J. Neumann
Psychiatric drugs have pleiotropic properties and are also antagonists at histamine receptors. Hence, we
tested the hypotheses: firstly that haloperidol or clozapine antagonize H2-histamine receptor-mediatedpositive inotropic effects in the human heart, secondly that mirtazapine antagonizes H1-histamine receptormediated positive inotropic effects in the human heart.
To this end, we measured isometric force of contraction of human right atrial preparations (HAP),
obtained during bypass surgery, in the organ bath. H1 histamine receptors in HAP were examined byadding 0.4 µM propranolol and 100 µM cimetidine first. Afterwards, concentration response curves tohistamine were established in HAP by applying histamine cumulatively from 10 nM to 100 µM. Then, inthe continuous presence of 100 µM histamine, we noted negative inotropic effects (NIE) for additionallyapplied clozapine or haloperidol (1 µM, 3 µM and 10 µM each). The NIE of clozapine was more
pronounced than the NIE for haloperidol. In some samples, pre-incubation with 1, 3, or 10 µM haloperidol
or clozapine was performed followed by a concentration response curve for histamine. In this way
clozapine but hardly haloperidol shifted the concentration response curve to histamine to the right,
suggesting H2-histamine receptor antagonism. In the presence of 0.4 propranolol, 100 µM cimetidine and100 µM histamine, mirtazapine (1 µM, 3 µM and 10 µM) exerted a time dependent NIE (n=4–6, p<0.05)
suggesting antagonism at H1-histamine receptors in HAP.
These findings suggest a NIE of clozapine by antagonism at H2-histamine receptors even in therapeutic
doses (1.1 – 1.8 µM). However, haloperidol has lower therapeutic plasma concentrations (13 – 45 nM).
Hence, effects will only be seen in accumulation or overdosage. Similarly, negative inotropic effects ofmirtazapine through H1-histamine receptor antagonism seem to start at therapeutic concentrations (151 –301 nM), but are more distinct at higher concentrations.
Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg,
D-06097 Halle (Saale), Germany
jonas.schlicht@student.uni-halle.deFLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION V IN MEMORY OF PROF. PIER F. MANNAIONI –HISTAMINE IN THE HEART & THE KIDNEY
CONTRACTILE EFFECTS OF HISTAMINE IN MICE OVEREXPRESSING H1HISTAMINE RECEPTORS AND H2-HISTAMINE RECEPTORS IN THE ATRIUM
T.H. Pham, L.M. Rayo Abella, U. Kirchhefer, J. Neumann, U. Gergs
In the human heart, H1- and H2-histamine receptors are coexpressed. To get a comparable mouse model,
we crossbred two mouse lines with cardiac myocytes-specific overexpression of either human H1histamine receptors (H1-TG) or human H2-histamine receptors (H2-TG) to obtain double transgenic mice(H1xH2-TG) and compared them with wild type mice (WT). We measured force of contraction in isolated
electrically stimulated left atrial preparations (LA) and spontaneously beating right atrial preparations(RA). In LA from WT, cumulatively applied histamine (1 nM – 30 µM) did not affect force of contraction.
In LA from H1xH2-TG, low concentrations (30 nM – 1 µM) of histamine exerted a positive inotropic
effect (PIE) whereas higher concentrations (3 µM, 10 µM, 30 µM) of histamine exerted a negative
inotropic effect (NIE). The PIE of histamine in H1xH2-TG was antagonized by 10 µM of the H2-histamine
receptor antagonist cimetidine, the NIE of histamine in H1xH2-TG was antagonized by 1 µM of the H1histamine receptor antagonist mepyramine. Higher concentrations of histamine (3 µM, 10 µM) led to anegative chronotropic effect (NCE) in RA from H1xH2-TG that was antagonized by 1 µM mepyramine.
Cumulatively applied dimaprit (1 nM – 10 µM), a H2-histamine receptor agonist, exerted at 300 nM andhigher concentrations only a PIE in LA from H1xH2-TG. Unexpectedly, 2-(2-Thiazolyl) ethyl amine(ThEA), a supposed H1-histamine receptor agonist, led only to a PIE and PCE in LA or RA from H1xH2TG, respectively. This controversy needs to be clarified through further experiments.
In summary, these data indicate that histamine first activates H2-histamine receptors and then H1-histamine
receptors.
Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – grant number
528629916.
Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg,
D-06097 Halle (Saale), Germany
hoai.pham@uk-halle.deFLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION V IN MEMORY OF PROF. PIER F. MANNAIONI –HISTAMINE IN THE HEART & THE KIDNEYTEMPERATURE SENSITIVE CONTRACTILE EFFECTS OF HISTAMINE IN MICEOVEREXPRESSING H1-HISTAMINE RECEPTORS IN THE ATRIUM
P. Grundig, J. Neumann, U. Gergs
Histamine does not alter force of contraction in left atrial preparations from wild type mice (WT).
However, histamine exerts an initial negative inotropic effect followed by a positive inotropic effect inisolated left atria of mice with cardiac-specific overexpression of human H1-histamine receptors (H1-TG).
We tested the hypothesis whether the cardiac effects of histamine might be temperature sensitive. Hence,
we measured under isometric conditions the effect of histamine on isolated atrial preparations under
normothermia (37°C), hypothermia (24°C), and hyperthermia (42°C) in the organ bath. Additionally, thespontaneous beating rate and force of contraction were measured in the absence and presence ofhistamine. Atria were pretreated with 0.4 µM propranolol to exclude any β-adrenergic effects. At
normothermia, histamine (1 µM) induced an increase in force of contraction in H1-TG. The transientnegative inotropic effect amounted to 14% (n=5, p<0.05). The relative increase in force in the biphasic
effect was about 26%. Under hypothermia, a force increase of 185% (n=5, p<0.05) was observed. The
relative increase in force in the biphasic effect was about 87%. However, under hyperthermia, histamine
failed to raise the force of contraction. The negative inotropic effect was about 61% (n=5, p<0.05). The
frequency at normothermia increases by 16%. Under hypothermia, there was a 105 % increase and under
hyperthermia, a 60% increase in frequency.
In WT, there was a decrease in contractile force, in hypothermia and hyperthermia. In WT right atria under
normothermia, we detected a 14% increase in beating rate, hypothermia exhibited a 182% increase, andhyperthermia showed a 26% increase.
In summary, there is a relation between temperature and force as well as beating rate in both TG and WT,
which varies depending on the expression of H1-histamine receptors. These effects may potentially haveclinical applications.
Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg,
D-06097 Halle (Saale), Germany
joachim.neumann@medizin.uni-halle.deFLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION V IN MEMORY OF PROF. PIER F. MANNAIONI –HISTAMINE IN THE HEART & THE KIDNEY
DIFFERENT ROLE OF HISTAMINE H1 AND H4 RECEPTORS ON THE EXPRESSIONOF AQUAPORIN (AQP)1 AND AQP7 IN THE HUMAN RENAL PROXIMAL TUBULE
CELL LINE HK-2
M. Molino, F. Foglietta, A. Pini, A. C. Rosa
Aquaporins (AQPs) are proteins for bidirectional water transport, that regulate numerous processes such as
urine formation and concentration. Among the isoforms present at the renal level, AQP1 and 7 are
specifically expressed in the proximal tubule, where histamine receptors H1 and H4 are also expressed andcontribute to reabsorption. Since histamine has already been described to regulate AQPs in nasal epithelial
and in gastric adenocarcinoma cells through histamine H1 and H2 receptors respectively, we aimed todemonstrate its effect in influencing AQP1 and 7 expression in the proximal tubule.
Human proximal tubule cells (HK-2) were exposed to histamine (from 0 to 100 nM) for 0 to 24 h and theexpression of AQP1-7 was evaluated by western blot analysis. Chlorpheniramine 1 µM and JNJ7777120 10µM were used to dissect the histamine receptor subtype contribute.
Histamine exposure resulted in a downward trend in the AQP1 level and a significant increase in AQP7
expression in a time- and concentration-dependent manner. An increased expression of the glycosylated
form- the functionally expressed one- of both AQP1 and AQP7 was also observed. To investigate the relative
contribution of histamine H1 and H4 receptors in the AQP glycosylation process, the same experiments wererepeated in the presence of the specific antagonists. The results clearly demonstrated that both H1 and H4
receptors are involved in the AQP7 glycosylation process, while only H4 receptors affected the AQP1 posttranslational modification.
The data suggest that histamine contributes to the dysregulation of renal resorption, a phenomenon
underlying many diseases characterized by polyuria, affecting the AQPs expression on tubular epithelial cell
membrane. However, further studies are needed to better understand how histamine influences the signaling
pathways involved in AQP1 and 7 expression.
Department of Experimental and Clinical Medicine, University of Florence, 50139 Florence, Italy;
marta.molino@unifi.it

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION V IN MEMORY OF PROF. PIER F. MANNAIONI –HISTAMINE IN THE HEART & THE KIDNEY
DIFFERENT ROLE OF HISTAMINE H1 AND H4 RECEPTORS ON THE EXPRESSIONOF AQUAPORIN (AQP)1 AND AQP7 IN THE HUMAN RENAL PROXIMAL TUBULE
CELL LINE HK-2
M. Molino, F. Foglietta, A. Pini, A. C. Rosa
Aquaporins (AQPs) are proteins for bidirectional water transport, that regulate numerous processes such as
urine formation and concentration. Among the isoforms present at the renal level, AQP1 and 7 are
specifically expressed in the proximal tubule, where histamine receptors H1 and H4 are also expressed andcontribute to reabsorption. Since histamine has already been described to regulate AQPs in nasal epithelial
and in gastric adenocarcinoma cells through histamine H1 and H2 receptors respectively, we aimed todemonstrate its effect in influencing AQP1 and 7 expression in the proximal tubule.
Human proximal tubule cells (HK-2) were exposed to histamine (from 0 to 100 nM) for 0 to 24 h and theexpression of AQP1-7 was evaluated by western blot analysis. Chlorpheniramine 1 µM and JNJ7777120 10µM were used to dissect the histamine receptor subtype contribute.
Histamine exposure resulted in a downward trend in the AQP1 level and a significant increase in AQP7
expression in a time- and concentration-dependent manner. An increased expression of the glycosylated
form- the functionally expressed one- of both AQP1 and AQP7 was also observed. To investigate the relative
contribution of histamine H1 and H4 receptors in the AQP glycosylation process, the same experiments wererepeated in the presence of the specific antagonists. The results clearly demonstrated that both H1 and H4
receptors are involved in the AQP7 glycosylation process, while only H4 receptors affected the AQP1 posttranslational modification.
The data suggest that histamine contributes to the dysregulation of renal resorption, a phenomenon
underlying many diseases characterized by polyuria, affecting the AQPs expression on tubular epithelial cell
membrane. However, further studies are needed to better understand how histamine influences the signaling
pathways involved in AQP1 and 7 expression.
Department of Experimental and Clinical Medicine, University of Florence, 50139 Florence, Italy;
marta.molino@unifi.it

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION V IN MEMORY OF PROF. PIER F. MANNAIONI –HISTAMINE IN THE HEART & THE KIDNEY

INVESTIGATION OF THE CROSS-TALK BETWEEN HISTAMINE AND RENAL CLC
CHLORIDE CHANNELS AND TRANSPORTERS IN A MOUSE MODEL OF DIABETIC
NEPHROPATHY
E. Conte, P. Imbrici, C.E. Monreale, M. Pati, A.C. Rosa, A. Liantonio
Different lines of evidence point out to a potential direct contribution of histamine to the renal
pathophysiology. In this context, histamine is emerging as a new mediator in diabetic nephropathy (DN),
the most common complication in patients with diabetes mellitus, being able to exert a series of activities
along nephron through the four subtypes of G-protein coupled receptors (H1-4Rs). Accordingly, H1R and
H4R are now considered promising drug targets, being H1R antagonist bilastine and H4R antagonist
JNJ39758979 able to prevent the alteration of several indexes of DN-associated renal dysfunction. In viewof the tubule-centric hypothesis of DN etiopathogenesis, renal ion channels and transporters could be
involved in histamine receptor-mediated polyuria and proteinuria. In this regard, ClC-K1 and ClC-K2
chloride channels and ClC-5 Cl⁻/H⁺ antiport are proteins belonging to the ClC family involved in thereabsorption of salt and low molecular weight (LMW) proteins, showing an overlapping expression
localization with H1-4Rs in specific nephron segments. Thus, we here explored the potential cross-talkbetween these renal ClC proteins and histamine by using the streptozotocin-induced murine model of DN,
showing histamine high levels, and by performing a gene and protein expression study. In line with polyuria
and proteinuria characterizing DN, a reduction of ClC-K1, ClC-K2 and ClC-5 gene and protein expression
was observed in kidney diabetic mice with respect to control mice. Preliminary results regarding theadministration of JNJ39758979 and bilastine allowed to gain insight into the specific involvement of HRs
in the regulation of ClC gene expression and indicated a key role for H1R. Our findings revealed that renal
ClC proteins can be considered new players in DN etiopathogenesis in relation to histamine-mediated kidney
dysfunction.
Department of Pharmacy – Drug Sciences,
University of Bari, Bari, 70125, Italy
elena.conte@uniba.it

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VI – HISTAMINE IN THE EYE
H4 HISTAMINE RECEPTOR UPREGULATION AND INFLAMMATORYRESPONSES IN AN IN VITRO MODEL OF DIABETIC RETINOPATHYPaul Chazot, M Hussan, S Grillo
Our knowledge of the underlying molecular mechanisms for the development of diabetic retinopathy is
still evolving. Chronic exposure to hyperglycaemia and other causal risk factors leads to a cascade ofbiochemical and physiological changes that ultimately causes retinal dysfunction and microvasculardamage. Müller cells are one of the primary glial cell types found in the retina, and since they are theonly cells that span the entire width of the retina and have contact with both retinal blood vessels andretinal neurons, they are uniquely positioned to perform a variety of functions to maintain retinal
function and homeostasis. It has been suggested that the breakdown of the blood retinal barrier is caused
by improper localization of the dystrophin-Dp71 protein as deletion of the protein causes the protein to
localize in the endfeet of Müller cells, thus causing extensive vascular leakage and oedema in the mouse
retina. There is an increased histaminergic tone associated with diabetes, and emerging evidence also
points to a role of histamine in the BBB breakdown that is associated with the pathogenesis of diabetic
retinopathy and vascular permeability, the H4 receptor is a potential target for therapeutic interventions
in diabetic retinopathy.
In this study, we explored the presence and role of histamine and the histamine H4 receptor, using
immunofluorescence, calcium signalling (Calciumgreen probe), and TNFα ELISA methods.
Immunofluorescence studies using HDC and H4 receptor-specific antibodies in the human Müller cellline Mio-1, showed the presence of histamine decarboxylase (HDC) and the H4 receptor in the cells, thelatter specifically in the projections of the cells. This fits well with the observation, in the mouse retina,
where H4 receptor labelling was prominent in the end-feet of the Müller cells (see above). When thehuman Müller cells were grown in high glucose media (4500mg/L D-Glucose), the expression of the
H4 receptor appeared significantly more prominent compared to when the cells were grown in standard
low glucose media. This is consistent with several studies that has implicated the role of histamine indiabetic conditions through upregulation of histamine in diabetic patients, and the histamine H4R
rodents, eg. kidney. Following administration of the selective H4 receptor agonist VUF8430 (100 nM)
to hyperglycaemic Mio cells, there is an increase in intracellular calcium, and TNFα, the former underbaseline conditions, and the latter under inflammatory stress conditions (glyoxal, 2 µM). Additionally,
when mice were fed a high fat diet (HFD) over 3 months, H4R appeared to be increased in the inner
plexiform layer of the retina. This suggests that HFD may increase the H4R expression at the synaptic
connections between bipolar cells and retinal ganglion cells. Overall, these data suggest the potential
use of a H4R antagonist drug in treating diabetic retinopathy.
Thanks Prof R Leurs for the sample of VUF8430.
Department of Biosciences, Durham University, UK;
Email: paul.chazot@durham.ac.uk

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VI – HISTAMINE IN THE EYEHISTAMINE STIMULATES CALCIUM-DEPENDENT TRANSMEMBRANE CATIONCURRENT THROUGH H1R-Gq/11 PATHWAY IN HUMAN RETINAL GLIAL MÜLLERCELLS
J. Strikland, R. Robson, I. Obara, M. Alsaqati, P.L. Chazot, P. Yarova and V. Telezhkin

Histamine is a ubiquitous autocoid that mediates a vast variety of physiological processes throughthe binding to one of its four G-protein coupled receptors (H1R, H2R, H3R and H4R). Using patchclamp electrophysiology in conventional whole-cell configuration, and calcium (Ca2+) imaging wefound that histamine induced powerful conductance that was associated with augmented
intracellular Ca2+ in human retinal glial Müller cells MIO-M1. Inhibition of the histamine effects
with H1R antagonist and phospholipase C inhibitor U73122 unveiled the signal transduction
through Gq/11 cascade. Suppression of intracellular Ca2+ signal and transmembrane current withxestospongin C confirmed further involvement of Ca2+ release from endoplasmic reticulum (ER)through inositol triphosphate receptors (IP3R), and passive depletion of ER stores with reticular
Ca2+ adenosine triphosphatase (Ca2+ ATPase) inhibitor cyclopiazonic acid (CPA) and Ca2+ chelator
BAPTA-AM verified store-dependence of the histamine signalling in human retinal glial Müller
cells MIO-M1. Sensitivity of the histamine signals with nominal Ca2+ free solution and NiCl2
highlighted importance of the extracellular Ca2+ influx, that was confirmed with 2APB the inhibitorof transient receptor potential channels, presumably melastatin (TRPM) subfamily. The expressionof H1R, TRPM7 and glial markers was confirmed using immunocytochemistry. Taken together, thisstudy establishes a novel H1R/TRPM7 mechanism that in human retinal glial Müller cells mightplay important role in retinopathies such as fluid accumulation in macular oedema andneovasculisation in diabetic retinopathy.
Authors would like to thank Prof. Astrid Limb (UCL) for kind gift of human retinal glial Müller
cells MIO-M1cells.
School of Dental Sciences, Newcastle University, Newcastle upon Tyne, NE2 4BW, UK
E-mail: vsevolod.telezhkin@newcastle.ac.uk

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VI – HISTAMINE IN THE EYE
H3R ANTAGONIST-CA INHIBITOR HYBRID COMPOUNDS IN A RABBIT MODEL OF
TRANSIENT OCULAR HYPERTENSION
L. Lucarini, S. Villano, S. Sgambellone, S. Marri, E. Masini, A. Nocentini, C.T. Supuran, F.
Iovane, M. Schultes, L. Leitzbach, T. Werner, H. Stark

Glaucoma is a leading cause of blindness, afflicting more than 60 million people worldwide with a
discouraging estimate of 111 million in 2040. It is an optic neuropathy, characterized by an imbalance
between production and outflow of aqueous humor (AH), generating an increase of intraocular pressure(IOP), the main risk factor of glaucoma. The histaminergic system plays an important role in the regulationof IOP through histamine H3 receptors (H3Rs) in the eye. Selective antagonists for H3R increase the AH
outflow, lowering IOP, and carbonic anhydrase inhibitors (CAI), such as dorzolamide (DRZ), can decrease
IOP. Current pharmacological therapies are effective in reducing it, but not all the patients are responsive,
and important side effects impair the compliance, accounting for the necessity of novel therapeutic
approaches. The aim of the research was to evaluate the capability of a new set of H3R antagonist-CAI
hybrid compounds, acting at different biological levels, in controlling high IOP. A transient ocular
hypertension (OHT) model in New Zealand White (NZW) rabbits was used to address the potential IOPlowering ability of newly designed potential hybrid compounds ST-2525, ST-2558, ST-2559 and ST-2493,
compared with ciproxifan and dorzolamide as reference drugs. The compounds were evaluated for inhibitory
activities at human H3R and on selected CA isoforms. The transient OHT model was induced by injectionof 50 µL of 5% hypertonic saline into the vitreous. IOP was measured with a Pneumotonometer at baseline
and 60, 120, and 240 min post treatment after OHT induction. The effects were maximal with ST-2525(Ki<10 nM for hH3R and hCA II and XII) at 60 min post-dose (DDIOP60’= -6.0±0.9 mmHg, at 1%),maintaining its activity at 120 min (DDIOP120’= -4.6±1.4 mmHg) and after 240 min (DDIOP240’= -4.4±0.9mmHg).
These results suggest that H3R antagonist-CAI hybrid compounds contribute in IOP regulation with a longlasting effect, and they could represent a future promising therapy for glaucoma.

Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), University of
Florence, Florence, 50139, Italy.

laura.lucarini@uniﬁ.it

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VI – HISTAMINE IN THE EYEEVALUATION OF FIBROTIC MARKERS IN AN ANIMAL MODEL OF OCULAR
HYPERTENSION TREATED WITH A HISTAMINE H3R/NO HYBRID COMPOUND
S. Sgambellone, S. Marri, S. Villano, A. Frank, D. Reiner, M. A. Khanfar, H. Stark, E. Masini, L.
Lucarini

Glaucoma is a degenerative ocular disease characterized by a degeneration of ciliary processes andtrabecular meshwork (TM). This malfunction triggers a series of cascading events that can lead toprogressive vision loss and finally blindness.
Fibrosis is a common pathological feature in many chronic diseases. It is a tissue repair response manifested
by excessive deposition of extracellular matrix (ECM) components such as collagen and fibronectin. ECM
synthesis and degradation are tightly regulated processes that play a critical role in maintaining TM integrity
and a dysregulation of these, can lead to fibrosis and impaired TM function. Severe fibrosis in the TM canlead to continuous abnormal ECM accumulation and distortion of the TM framework, resulting in increased
resistance to aqueous humor outflow and elevated intraocular pressure (IOP).
Histamine receptors are known to have an important role in glaucoma, and histamine H3 receptor (H3R)
antagonists have been shown to be effective in ameliorating the glaucomatous condition. Based on thisevidence this research aimed to evaluate whether a H3R antagonist hybrid compound could reverse thefibrotic process in a chronic ocular hypertension (OHT) model. The chronic OHT was carried out on New
Zealand White rabbits by a single injection of 100 μl of Carbomer 0.25% (Siccafluid, Farmila THEA
Pharmaceutical) in the anterior chamber of the eye resulting in ocular hypertension that persisted for 14
days. The animals were treated with a H3R antagonist/NO donor hybrid compound ST-1989 and its reference
drugs, Ciproxifan and Molsidomine, both administered alone and in combination. In ocular tissues, the TGFβ signaling pathway was assessed by determining TGF-β1 levels (ELISA KIT),
SMAD3, P-SMAD3 and α-SMA via Western blot and immunofluorescence analysis.
These preliminary results demonstrate that this compound reduces fibrotic markers confirming that it could
represent a good strategy for the therapeutic treatment of glaucoma.

Department of Neuroscience, Psychology, Drug Area and Child Health (NEUROFARBA),
Viale Pieraccini, 6, 50139 Florence, Italy.
silvia.sgambellone@uniﬁ.it

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VI – HISTAMINE IN THE EYEPHOTOSWITHCHABLE COMPOUNDS IN A TRANSIENT OCULAR
HYPERTENSION (OHT) MODEL IN NEW ZEALAND WHITE (NZW) RABBITSMarri S., Sgambellone S., Villano S., Masini E., Zheng Y., Leurs R., Lucarini L.

Glaucoma, a pathology involving retinal ganglion cells (RGCs), is an urgent public health disease.
According to the World Health Organization (WHO), glaucoma is the second leading cause of blindness.
This pathology is mainly caused by high intraocular pressure (IOP) caused by a disequilibrium between the
production and outflow of aqueous humor (AH). Three subtypes of β-ARs (β1, β2, and β3) have been
identified with different distributions among ocular tissues. β-ARs are an established target in the treatmentof glaucoma. Even, phosphodiesterase type 5 (PDE5) is a key enzyme involved in the regulation of cGMPspecific signaling pathways in normal physiological processes, such as smooth muscle contraction andrelaxation. For this reason, inhibition of PDE5 can alter pathophysiological conditions associated with low
cGMP level in tissues. We studied two different types of photswitchable compounds: the β2 blockers(VUF25474 cis and trans) compared to propranolol and the PDE5 inhibitors (VUF25334 cis and trans)compared to sildenafil. Photoswitches are molecules that undergo structural changes in response to lightirradiation. A transient ocular hypertension (OHT) model in New Zealand White (NZW) rabbits was used
to study the potential IOP-lowering ability of the photoswichable compounds. This model was induced byinjection of 50 µL of 5% hypertonic saline into the vitreous. IOP was measured with Pneumatonometer atbaseline and 60, 120 and 240 min post treatment after transient OHT induction. The effects were maximal
with VUF25474 cis 0.1% and with VUF25334 0.05% cis at 60 min post-dose. Concerning VUF25334 the
IOP remained stable at 120 min post-dose and decayed thereafter to reach baseline values at 240 min. These
results exhibited that photoswitchable compounds provided a long-lasting effect in IOP regulation, and they
could be a future promising treatment for glaucoma. A novel recent approach represents an in vitro model
to study these compounds with trabecular meshwork (TM) cells, that were treated with different
concentrations of VUF25474 and VUF25334 in order to study histamine receptor signalling.

Department of NEUROFARBA, Section of Pharmacology, University of Florence, Florence,
50139,
Italy. silvia.marri@unifi.it

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VI – HISTAMINE IN THE EYESTUDY OF microRNA INVOLVED IN OCULAR ISCHEMIA PATHWAY
S. Villano, S. Marri, S. Sgambellone, D. Reiner, M. A. Khanfar, E. Masini, H. Stark, L. Lucarini

Ocular ischemia is a pathological condition consisting in a restriction of blood flow related to various
diseases, such as diabetic retinopathy or glaucoma.
At retinal level, ischemia alters the homeostatic balance between angiogenic and angiogenetic factors that
limits aqueous humour outflow into the anterior chamber of the eye, resulting in increased IOP. An
impairment of optic nerve head (ONH) vascular perfusion contributes to progressive depletion of retinal
ganglion cells (RGCs) and optic nerve degeneration. In glaucomatous disease, the continuous IOP
oscillation causes repeated ischemia/reperfusion (I/R) phenomena producing reactive oxygen species (ROS)
that enhance tissue injury. The histaminergic system plays an important role in the maintenance of ocularvascular tone. Histamine H3 receptors (H3R) antagonists are known to be effective in ameliorating ocularvascular performance and preventing RGCs death. Nitric oxide (NO) is a pivotal molecule for the regulationof blood flow; in fact, NO donors are used for the treatment of several ocular diseases. MicroRNAs(miRNA) are implicated in oxidative stress, hypoxia and inflammation regulation. The aim of this researchis to evaluate the modulation of histamine receptors and miRNA expression in ocular ischemia. The I/Rmodel was carried-out in New Zealand White Rabbits by repeated injections of ET-1, twice a week for 6
weeks. Animals were treated with vehicle or ST-1989 1%, a histamine H3 antagonist-NO donor hybrid
compound, bid for 4 weeks. On ocular tissues, we evaluated miR-29b, that is involved in trabecularmeshwork (TM) extracellular matrix (ECM) deposition through NF-Kb and TGF-β2 regulation pathway,
miR-182, that acts as anti-oxidative and anti-apoptotic factor, miR-210 and miR-21, that are hypoxiainduced miRNAs.
The different expressions of these miRNAs confirm their involvement in ocular ischemia signalling
pathways. Therefore, they can be used as a versatile tool for disease detection and may also be promisingtherapeutic targets.

Department of NEUROFARBA, Section of Pharmacology, University of Florence, Florence,
50139,
Italy. silvia.marri@unifi.it

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VII – HISTAMINE IN INFLAMMATION AND IMMUNITYHISTAMINE UPREGULATES THE EXPRESSION OF MMP12 IN HUMAN M2
MACROPHAGES
Alice Pereira da Fonseca, Stephan Traidl, Ralf Gutzmer, Katrin Schaper-Gerhardt, Thomas Werfel, Susanne
MommertBeyond Th2 cells and various immune cells, M2 macrophages have been identified in lesional skin of atopic
dermatitis (AD) indicating their involvement in the disease’s underlying mechanisms. MMP12, a matrixdegrading enzyme, which is predominantly produced by macrophages, is increased in skin lesions of AD
patients.
Our aim was to investigate the expression of MMP12 in M2 macrophages from healthy individuals and AD
patients in response to Th2 cytokines and histamine. Additionally, macrophages from dupilumab-treated AD
patients were analysed to assess the influence of Th2 cytokine on MMP12 expression ex vivo.
The expression of MMP12 mRNA in lesional skin of AD was evaluated at the single cell level through RNA
sequencing (scRNA-seq) published previously in detail.
M2 macrophages derived from both healthy donors and AD patients were stimulated with IL-4 or IL-13,
with histamine or specific histamine receptor agonists (H1R, H2R, H4R) either during or after
differentiation. MMP12 mRNA expression was analysed using quantitative PCR. MMP12 concentrations
in cell supernatants were measured via ELISA.
ScRNA seq analysis identified macrophages as the primary producers of MMP12 in lesional AD skin. In
vitro, both MMP12 mRNA and protein expression were significantly increased in monocytes during
differentiation to M2 macrophages in the presence of histamine, of Th2 cytokines or of Th2 cytokines incombination with histamine.
In M2 macrophages obtained from dupilumab-treated AD patients, the upregulation of MMP12 expression
by IL-4 and IL-13 was attenuated.
Our findings reveal a novel mechanism by which Th2 cytokines and histamine regulate MMP12 expression,
which may affect skin barrier homeostasis in AD.

Susanne Mommert mommert.susanne@mh-hannover.de Department of Dermatology and Allergy,
Hannover Medical School, Carl-Neuberg Strasse 1, 30625 Hannover, Germany

ORAL PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VII – HISTAMINE IN INFLAMMATION AND IMMUNITYASSESSING THE ANTHELMINTIC POTENTIAL OF ANTIHISTAMINES H1 AGAINSTANGIOSTRONGYLUS CANTONENSIS
F. B. Lopes, D. B. Roquini, B. Lima, J. de Moraes, J. P. S. Fernandes
Angiostrongylus cantonensis is a nematode that develops in molluscs and infects a variety of vertebrates,
mainly rodents. Nonetheless, this parasite may cause human infection (angiostrongyliasis) after ingestionof contaminated food. After infection, the larvae migrate to the CNS, leading to eosinophilic meningitis,
causing fever, headache and meningismus. To date, there is no specific treatment against
angiostrongyliasis and therefore the search for therapeutic agents is needed. Considering the neglected
status of worm infections on drug discovery programs, drug repurposing is an option to accelerate thesearch for drugs against helminthiasis, being this worm an interesting model for drug discovery against
helmints. Since antihistamines were already reported as potential agents against a variety of parasites,
including Trypanosoma cruzi, Leishmania infantum and also Schistosoma mansoni, in this work ascreening of clinically available antihistamines was performed. A set of 21 anti-H1 antihistamines
commercially obtained were screened against first-stage larvae (L1) of A. cantonensis (n = 100
larvae/well), isolated from the feces of infected rats through Rugay’s method. The althelmintic activity
was measured by standardized score (effect >60%): 1 (immotile), 2 (intermittent shaking of the head or
tail region), 3 (sluggish and motile), 4 (highly active and motile). Anthelmintic drugs ivermectin andalbendazole were used as standard drugs. The results showed that four drugs (cinnarizine, desloratadine,
promethazine and rupatadine) were active against the parasite, being promethazine the most potent (IC50
31.6 µM). The activity has no direct correlation to the affinity to histamine receptor, but other mechanisms(affinity to cholinergic receptors or histamine-response proteins) may be involved. This is the first reportof the activity of antihistamines against A. cantonensis, an important contribution to the search of novel
agents active against nematodes.

Department of Pharmaceu0cal Sciences, Federal University of São Paulo, 09913-030 Diadema-SP, Brazil
joao.fernandes@unifesp.br

FLASH PRESENTATIONS ABSTRACTSCIENTIFIC SESSION VII – HISTAMINE IN INFLAMMATION AND IMMUNITYCYCLOPHOSPHAMIDE AUGUMENTS HUMORAL IMMUNITY AND DRUGRESISTANCE AGAINST L-ASPARAGINASE
Mitsunobu Mio, Ai Nogami-Hara, Emika Mori, Saori Chabatake, Akira Shimada
L-Asparaginase (ASNase), a key drug in the treatment of childhood acute lymphoblastic leukemia, oftencauses allergic reactions and drug resistance. However, when mice were sensitized with ASNase alone, theallergic response as well as IgE production were lower than those induced by ovalbumin. In the present
study, among the drugs concomitantly used with ASNase, we examined the effect of cyclophosphamide(CY) on the immune response to ASNase.
Male BALB/c mice were intraperitoneally sensitized by ASNase and alum. CY was intraperitoneallyinjected 2-day prior to ASNase sensitization. Allergic skin reaction to ASNase was evaluated by measuring
ear thickness after intradermal challenge of ASNase into the ear lobe. Total IgE level and ASNase activity
in the sera were measured. RBL-2H3 cells were sensitized by the sera of immunized mice and the cells were
stimulated by ASNase to determine β-hexosaminidase (β-Hex) release. Spleen cells of immunized mice
were cultured for 48 hrs with concanavalin A and cytokines in the medium were measured using a Bio-Plex
Th1/Th2 assay kit.
ASNase sensitization induced ear edema and increased serum IgE levels in mice. CY at 150 mg/kg
augmented these responses. CY at 300 mg/kg increased serum IgE levels, but decreased ear edema andserum ASNase activity. Sera of CY 150 mg/kg-treated mice induced higher β-Hex release from RBL-2H3
cells than normal anti-ASNase sera, though those of CY 300 mg/kg-treated mice did not induce β -Hex
release. After removing IgG from the sera of CY 300 mg/kg-treated mice, β -Hex release became higher
than normally sensitized mice. ASNase sensitization induced a Th2-biased immune response, and the
addition of CY further enhanced the Th2-biasd response in a dose-dependent manner.
CY administration enhanced Th2-biased immune responses and increased IgE and IgG production in the
ASNase-sensitized mice. These findings suggest that CY may play a role in the development of ASNaseallergy and drug resistance.
Laboratory of Pharmacology, School of Pharmacy, Shujitsu University, Okayama, 703-8516, Japan
mio@shujitsu.ac.jp

EHRS International Anthem
Mel.Polly Waddle Doodle
CHORUS:For it ś mine, for it ś mine,
Decarboxylated Histidine.
We v
́ e extracted you and weighed you.
By the living gut assayed you.
But we v
́ e yet to find your function-Histamine!
1. We talk of toxicosis / migraine, shock or halitosis
Singing Histaminosis all the day
Trauma, burns and inflammation / headache, pain andconstipation
Singing Histaminosis all the day
2. You give asthmatic wheezes / the allergic sneezes
Singing Histaminosis all the day
Though obscure as yet, the fact is / you ŕ e involved inanaphylaxis
Singing Histaminosis all the day
3. Since the time of Dale and Barger / your files are longer,
largerSinging Histaminosis all the day
The control of circulation / then gastric stimulation
Singing Histaminosis all the day
4. Mast cells by the dozen / and basophils your cousin
Singing Histaminosis all the day
They come and they go / fluctuate to and fro,Singing Histaminosis all the day
CHORUS
5. We heard a lot of groaning / from the upstart, Serotonin
Singing Histaminosis all the day
Down with 5-hydroxytrypta / and up with good old hista,
Singing Histaminosis all the day
6. Each year we meet in May / to concentrate and play,
Singing Histaminosis all the day
What luck to have such friends / to cater for our trends
Singing Histaminosis all the day
7. In nineteen seventy two / to Paris we all flew,
Singing Histaminosis all the day.
Then Marburg upon Lahn / where Wilfried kept us calm,Singing Histaminosis all the day.
8. Copenhagen as next year / the Mermaid to cheer,
Singing Histaminosis all the day.
In nineteen seventy five / Florence kept us alive,
Singing Histaminosis all the day.
CHORUS
9. To Paris for the next / to hear a new text,
Singing histaminosis all the day.
In nineteen seventyseven / London, it was Heaven,
Singing Histaminosis all the day.
10. Then Lodz with great care / we learned a lot there,
Singing Histaminosis all the day.
In nineteen seventy nine / to Stockholm this timeSinging Histaminosis all the day.

11. Then to Budapest we went / with Susan on the scent,Singing histaminosis all the day.
West Germany again / for Hannover by name,Singing Histaminosis all the day.
12. In nineteen eightytwo / to Bled we all flew,
Singing Histaminosis all the day.
Then Brighton to the fore / with sea breezes by the shore,
Singing Histaminosis all the day.
CHORUS
13. And in nineteen eightyfour / back in Florence likebefore,Singing Histaminosis all the day.
Then in Aachen eighty five / Charlemagne became alive,
Singing Histaminosis all the day.
14. Then in Odense in spring/ in the Castle we did sing,Singing Histaminosis all the day.
And then Czecho was the next / with our Rado at his best,
Singing Histaminosis all the day.
15. G.B. West was then cheered / for the ten years we d́been steered,
Singing Histaminosis all the day.
Let us sing this song together / Histamine will last forever,Singing Histaminosis all the day.
16. And in nineteen eight nine / it was also fine,We ŕ e in Holland for the very first time.
To Kuopio in Finland / to the beautiful, but cold land,
we were watching the Finnish chopping wood.
CHORUS
17. Then to Marburg we returned/ ninetyone and also
learnedThat histamine in surgery ś no good.
The next year we met again / Manuel in sunny Spain,
Singing ai, ai and olé all the way.
18. Then with Eddy on the Rhine, we had more beer thanwine,
Singing histaminosis all the day.
To Zsuzsanna ninety four / we went back to Danube shore,
Singing Histaminosis all the day.
19. Then with Igor ninetyfive / and the Volga was alive
And we entered the Russian Golden Ring.
In Antwerpen ninetysix / Frans did show us a few tricks,
Singing Histaminosis all the day.
20. To Seville, once again / we all met in lovely Spain,
Singing Histaminosis all the day.
To Agnieszka ninetyeight / back in Poland it was great,
Singing Histaminosis all the day.
CHORUS
21. Then to Lyon ninetynine / and Histamine’s still mine
Singing Histaminosis all the day.
New Millennium in Rome / Bruno made us all feel home
Singing Histaminosis all the day.
22. Pertti took us on a boat / we and Histamine could float
So to Turku we came two thousand one.
András called two thousand two / and to Eger did we go
To a meeting in Hungary again.

23. In the year two thousand three / we did lots of tulipssee
Now Henk Timmerman was host in Amsterdam.
Back to Germany next spring / and with Helmut did we
singSinging Histaminosis all the day
24. Then to Bled we return / and once again could learn
That Histamine still lives two thousand five.
Then to Delphi we all came / and found Histamine thesameWith Catherine in Greece two thousand six.
CHORUS
25. Back to Florence the next year / For the third time wewere here
And for us Emanuela made the day!
Back to Stockholm that we knew / with a lovely water view
With Anita in the North two thousand eight.
26. Then to Fulda the next year / we ŕ e in Germany to hear
How our Frido with Histamine can play.
And to Durham we went then / in the year two thousandten.
There with Paul near Cathedral did we stay.
27. Then two thousand and eleven / there in Sochi it was
heavenWhen our Roman he did the Russian way
Then to Belfast the next year / it was lovely, Maddie dear
Irish meeting was excellent in May.
28. Then to Łódź again next year / for the fourth time wemeet here!!
Dear Agnieszka both Honorar and chair.
In two thousand and fourteen / Then Lyon was back on
scene
And our Lin made it most amazing there.
CHORUS

29. Then to Málaga again / where it´s sun and never rain
And with Kika this was a lovely stay
In two thousand and sixteen / Florence once again wasseen
In a gorgeous Emanuela way.
30. Then from Rob we got a call / Amsterdam invited all
Coming back to the sparkling Tulip Land
In two Thousand and eighteen / Lovely Dublin was thescene
There with Astrid a meeting really grand.
31. Back to Poland the next year / we for Katarzyna cheer
Splendid chemist in a lovely Krakow town.
The Pandemic came along/ with no meetings and no song
But then Histamine will always be are own
32. Then in twentytwentytwo/ Back to Hannover we flew
Celebrating the splendid 50 Years!
Then in Turin twenty four / the meetings will be more
And our Histamine will live for many years
CHORUS