bluuebunny/crossref_metadata_2025_split huggingface dataset:
P142 Genetic ablation of DNA methyltransferase 3A in myeloid cells impairs M1/M2 polarization and leads to pro-inflammatory macrophages
Authors: Bordoni D , Escudero-Hernández C , Kimmig F , Mishra N , Fazio A , Tran F , Imm S , Hinrichsen F , Weber-Stiehl S , Stengel S , Sommer F , Falk-Paulsen M , Rosenstiel P 
Published: January 2024

Abstract

Background
Genetic variants in the de novo DNA methyltransferase DNMT3A associate with increased risk for inflammatory bowel disease (IBD). While DNMT3A loss-of-function somatic mutations have been attributed to myelodysplasia and acute myeloid leukemia, the exact mechanisms how defective DNMT3A is linked to IBD remain elusive. Since macrophages are key gatekeepers for immune homeostasis, we aimed to characterize how DNMT3A loss affects monocytic lineage differentiation and inflammatory properties.

Methods
We generated mice lacking Dnmt3a expression in myeloid cells (Dnmt3aLysM) using a LysM-driven cre-lox system and confirmed gene deletion by PCR and western blot of gut lamina propria CD11b+ enriched cells and 5-day in vitro differentiated bone marrow-derived macrophages (BMDM, 20ng/mL M-CSF). Four-day polarized BMDMs (resting: 20ng/mL M-CSF; M1: 50ng/mL LPS/IFNγ; M2: 50ng/mL IL-4/IL-13) were functionally characterized using RNA-seq, flow cytometry, and arginase and nitric oxide synthase (NOS) activities. FITC-labelled zymosan served to quantify phagocytosis, and co-culture with intestinal epithelial ModeK wounded monolayers to assess healing. To evaluate Dnmt3a loss during inflammation in vivo, colitis was induced using dextran sodium sulfate (DSS).

Results
M2 polarization induces Dnmt3a expression in wild-type (WT) BMDMs while inflammatory stimuli decrease it. Dnmt3a-deficient BMDMs differentiated with IL4/IL13 in vitro increase ERK1/2 and PI3K signaling, decrease M2 markers and upregulate inflammatory transcripts, e.g. Irg1,Tnf compared to WT cells. IL4/IL13 treated BMDMs confirmed M2 polarization defects as they acquire morphological and functional M1-like features in the absence of Dnmt3a, especially those from aged (&gt;34 weeks old) mice, e.g. failed spindle M2 morphology, increased phagocytosis, decreased arginase and increased NOS activities. In co-cultures, IL4/IL13 treated Dnmt3aLysM BMDMs inhibited intestinal epithelial regeneration after a scratch lesion compared to M2 WT BMDMs. Increased NOS activity was also detected in M1-polarized BMDMs from aged Dnmt3aLysM mice. In vivo, young Dnmt3aLysM mice display mildly increased splenic T-cell and decreased monocyte numbers. Aged Dnmt3aLysM mice (&gt;34 weeks) exhibit altered bone marrow morphology and hepatosplenomegaly linked to increased myeloproliferation. Dnmt3aLysM mice already at young age displayed increased sensitivity to both acute and chronic DSS colitis.

Conclusion
Normal Dnmt3a function is required for physiological macrophage polarization. Deletion of Dnmt3a in mice leads to a pro-inflammatory skewing particularly after M2-inducing cytokines IL4 and IL13. Our findings provide insights on how DNMT3A – via its specific function in myeloid cells – contribute to IBD pathogenesis.
P143 Efficacy of the oral tyrosine kinase 2 (TYK2) inhibitor TAK-279 in two preclinical mouse models of colitis
Authors: Kong K F , Khan M A W , Singh N , Nguyen V A , Wilson E , Tang J , Marusic S , Xia G , Petrakis I , Nguyen D G 
Published: January 2024

Abstract

Background
Tyrosine kinase 2 (TYK2), a member of the Janus kinase (JAK) family, is required for the downstream signalling of interleukin (IL) 12 and 23, and interferons (IFN) α/β, which are involved in the pathogenesis of several autoimmune diseases, including inflammatory bowel disease (IBD).1 JAK inhibitors are approved for treatment of IBD, but their dosing levels may be limited due to adverse effects related to JAK1–3 inhibition. TAK-279 is a highly-selective, oral, allosteric TYK2 inhibitor, which binds to the JAK homology 2 pseudokinase domain of TYK2, but not JAK1–3.1,2 This study assessed the efficacy of TAK-279 in two IL-23-dependent preclinical mouse models of colitis induced by (i) adoptive T-cell transfer (TCT) and (ii) anti-CD40 monoclonal antibody (α-CD40 mAb).

Methods
In the TCT colitis model, CD4+CD45RBhi T cells were transferred to severe combined immunodeficient mice at Day 0, and disease progression followed for 48 days. In the α-CD40 colitis model, T- and B-cell-deficient Rag2-/- mice were challenged with agonistic α-CD40 mAb at Day 0, and disease severity analyzed on Day 7. Mice were divided into four groups per model (n = 12–16 and n = 10 per group in the TCT and α-CD40 models, respectively) to receive vehicle (negative control) or TAK-279, orally, twice-daily, at doses intended to provide either 24hr IC90 (high dose) or IC50 (low dose) coverage, or once-weekly intraperitoneal α-IL-12/23 p40 mAb (positive control). At the end of the treatment period, colonic tissue was obtained; colon weight:length (CWL) ratio, total histology score (THS) and transcriptomic analysis were used to assess efficacy and mechanism of action. Statistical significance of differences between groups was determined using analysis of variance with Tukey’s post hoc test.

Results
In both models, TAK-279 was maximally efficacious at the IC90 dose; CWL ratio and THS were significantly reduced relative to vehicle and the response was comparable with α-IL-12/23 p40. IC50 dosing was not sufficient in the α-CD40 model and IC90 dosing was required for significant efficacy (Figure). Transcriptomic analysis showed TAK-279-dependent downregulation of genes associated with cytokine signalling, including those related to T-helper 17 cell phenotypes and the IFN α/β pathway.

Conclusion
TAK-279 was efficacious in two preclinical mouse models of colitis and induced relevant cytokine signalling changes; IC90 coverage provided maximal efficacy in both models. These results support the potential role of potent and selective TYK2 inhibition for the treatment of IBD, where TAK-279 is expected to achieve IC90 coverage in humans.
1. Leit S et al. J Med Chem 2023;66:10473–96.
2. Gangolli EA et al. STAT 2022;1:5.
P145 Phagocyte responses to gut-derived C. albicans are modified in inflammatory bowel disease
Authors: Mathew L , Carlson S , Savage M , Pardieu C , Sze N , Munro C , Naglik J , Stagg A , Kok K , Lindsay J O , McCarthy N 
Published: January 2024

Abstract

Background
Fungi are a key component of the human gut microbiota and have been strongly implicated in the pathogenesis of inflammatory bowel disease (IBD). Candida albicans typically exists as a commensal yeast within healthy hosts but can form tissue-invasive filaments that secrete Candidalysin (CLYS) toxin to disrupt epithelial barriers. Dynamics of this morphological switch are influenced by genotypic and phenotypic variation of gut-resident C. albicans strains, which may impact host response and extent of mucosal inflammation.

Methods
C. albicans isolates were derived from healthy control (HC) and IBD gut biopsies. Phenotypic, genomic, and proteomic analyses were conducted on these isolates. To further understand host interplay with intestinal C. albicans under physiologically relevant conditions, a human ‘gut-on-a-chip’ system was developed to assess tissue invasion potential in vitro.

Results
IBD-derived isolates were more readily able to form filaments, displayed altered cell wall composition, and modulated expression of adhesion-associated genes including IHD1. Subsequent innate leukocyte responses to these strain-dependent profiles were investigated to understand impact on host immunity. When exposed to IBD-derived C. albicans strains, blood neutrophils from healthy donors displayed increased swarming behaviour and NETosis induction, whereas monocyte-derived macrophages released greater amounts of pro-inflammatory IL-1b. These responses were substantially diminished in neutrophils and macrophages from IBD patients, suggesting altered reactivity to fungal stimuli in disease settings. The gut-on-a-chip model system confirmed that IBD-derived strains display increased adhesion and translocation in a dynamic human gut environment.

Conclusion
Gut-adapted C. albicans strains from HC and IBD donors exhibit distinct biological profiles that impact on host immune responses and shape interactions with the gut barrier in a novel organ chip model.
P147 IBD relevant pathways are upregulated in Paneth cells in a murine model of dietary induced intestinal inflammation
Authors: Grabherr F , Meyer M , Christina P , Marteau V , Schwärzler J , Mayr L , Enrich B , Jukic A , Grander C , Trajanoski Z , Tilg H , Adolph T E 
Published: January 2024

Abstract

Background
Dietary constituents are believed to play a role in the development of Crohn’s disease (CD) (1). Recently we were able to demonstrate, that polyunsaturated fatty acids (PUFA), induce a CD like enteritis phenotype in genetically susceptible mice (2,3). Furthermore, we could show, that PUFA intake correlated negatively with disease course in CD patients (3). In this project we tried to untangle the role of Paneth cells (PC) in the development of PUFA induced enteritis.

Methods
scRNA sequencing was performed on cells isolated from mice lacking one allele of Gpx4 (GPX4+/-IEC) in their intestinal epithelial cells (IEC) after feeding them a PUFA enriched western style diet (PUFA-WD). Furthermore, mice lacking both alleles of Gpx4 in their PC (GPX4ΔPC) where fed a PUFA-WD for four weeks and enteritis was assessed based on a histological enteritis score and immunhistochemical stainings.

Results
scRNAseq of murine intestinal cells revealed an upregulation of IBD relevant pathways (such as JAK or TNFα) in Gpx4 deficient IECs and PC. GPX4ΔPC mice developed a CD like enteritis phenotype, characterized by a mucosal and submucosal infiltration of neutrophils, macrophages and other leucocytes, after only four weeks of PUFA enriched diet, indicating that GPX4 dependent intestinal inflammation is controlled by PC.

Conclusion
The upregulation of IBD relevant pathways in our model of dietary induced intestinal inflammation renders this model a valuable tool to investigate mechanistical understanding in the role of dietary components in IBD. Our results further link PC metabolism to the development of intestinal inflammation.

References
1. Adolph TE, Meyer M, et al Nat Rev Gastroenterol Hepatol 2022
2. Mayr L, Grabherr F, et al Nat Com 2020
3. Schwaerzler J, Mayr L, et al Gastroenterology 2022
P150 Ulcerative Colitis Patients’ Luminal Zinc Induces Clostridioides difficile Virulence and Exacerbates Inflammatory Responses
Authors: Wu T , Zhou H , Li X , Lin J , Wang F , Da Y , Liang J 
Published: January 2024

Abstract

Background
The refractory acute severe UC patients are often complicated by C. difficile infection (CDI), resulting in higher surgery and mortality rates. However, few studies have observed C. difficile’s pathogenicity in real UC patients’ gastrointestinal microenvironments, and the actual role of C. difficile in UC development remains unknown. We found zinc concentrations among UC patients’ feces were significantly higher than those among Crohn’s disease patients and healthy subjects. Additionally, we previously reported that excessive zinc would promote the growth and virulence of C. difficile. Therefore, we hypothesized that the increased UC patients’ luminal zinc may up-regulate C. difficile virulence and promote intestinal inflammatory responses, leading to an exacerbated UC progression.

Methods
UC patients’ stool samples (n=40) were collected and analyzed by qPCR and ICP-MS to determine the presence of C. difficile and the fecal zinc concentrations. C. difficile was cultured in BHIs with or without zinc (ZnSO4) in an anaerobic chamber. Expression of virulence genes was analyzed using RT-qPCR, transcriptome sequencing, and western blot. Human colonic organoids and Caco-2 cells were co-cultured with C. difficile or zinc-treated C. difficile, and cytotoxicity, permeability, and inflammatory cytokine release were assessed. TLR5 knock-out Caco-2 cells were constructed using sgRNA-guided Cas9 nuclease and co-cultured with C. difficile or zinc-treated C. difficile to verify whether zinc-induced C. difficile’s pathogenicity was mainly through flagellar formation.

Results
C. difficile was detected in ~35% of UC patients’ fecal samples. Luminal zinc concentrations (~915μM, p&lt;0.01) were significantly higher among UC patients than CD patients or healthy subjects. The UC patients’ luminal concentration of zinc promoted C. difficile growth, suppressed its exotoxins release, and induced higher expression of its flagella-related genes, resulting in higher cytotoxicity and inflammatory responses in human colonic organoids and Caco-2 cells. However, zinc-treated C. difficile did not induce higher inflammation and pathogenicity in TLR5 knock-out Caco-2 cells.

Conclusion
The association between C. difficile and UC aggravation may partially stem from UC patients’ excess luminal zinc promoting C. difficile flagellin expression, inducing inflammatory responses, and worsening UC progression.
P152 Longitudinal immune profiling of peripheral blood in patients with Ulcerative Colitis
Authors: Wider-Eberspächer E , Garza A P , Albrecht T , Rosania R , Dunay I R 
Published: January 2024

Abstract

Background
Recent literature has established the communication and mutual influence between the gut and the brain, referred to as the gut-brain axis. While inflammatory bowel disease (IBD) poses a risk for neuroinflammation and brain dysfunction, the molecular mechanisms are not fully understood. This study aims to investigate longitudinal changes during Ulcerative Colitis (UC), focusing first on the characterization of peripheral immune cell subsets, circulating cytokines, and extracellular vesicles (EVs).

Methods
In our study, we examined 19 UC patients in both active (mean age in years: 45,63) and remission phases (mean age in years: 46,16). A gastroenterologist at the Gastroenterology Department from the Otto-von-Guericke University in Magdeburg, Germany assessed all participants, categorizing them into stages using Mayo scoring and calprotectin levels. We analysed peripheral whole blood and plasma samples using different flow cytometry-based approaches.

Results
Our findings indicate an upregulation of the neutrophil (CD16+, CD15+) numbers during the active stage followed by a significant reduction during remission, indicating an increase in innate inflammation as a first line of defence and a balanced state during remission. Classical (CD14+, CD16-) monocytes were decreased, along with similar results in the intermediate (CD14+, CD16+) subset. Nonclassical monocytes (CD14+, CD16++) increased from the active to the remission stage. Surface expression of activation marker CCR2 was downregulated for all monocyte subsets, whereas CX3CR1 was upregulated specifically in intermediate monocytes during remission. Compared to the active stage peripheral dendritic cell (CD14-, CD16-) numbers increase during remission suggesting less colonic infiltration. Peripheral regulatory T cells (Tregs) (CD127 low/-, CD25+), which are important for the reestablishment of homeostasis are upregulated during remission. Characterization of cytokine levels in plasma revealed an upregulation of the proinflammatory milieu during the active stage, especially with elevated IL-18 and TGF- β1 levels. Finally, those changes were accompanied by alterations of the surface markers expressed by isolated circulating EVs.

Conclusion
Our initial results indicate the feasibility of evaluating the gut-brain axis through liquid biopsy. We unravel the composition of the peripheral inflammatory milieu during the active phase. Currently we are focusing on the assessment of the CNS-derived metabolites and their bidirectional communication with the gastrointestinal system.
P155 Evaluation the role of interleukin-22 in inflammation related intestinal fibrosis: its potential influence on gut microbiota or immune system
Authors: Bai X , Runing Z , Hong Y 
Published: January 2024

Abstract

Background
The role of interleukin-22 (IL-22) in inflammation-related intestinal fibrosis remains largely unknown. Previous studies considered it as a double-edged sword between anti-inflammation and fibro-genesis in a tissue-specific manner. Therefore, we aimed to investigate the role of IL-22 in colonic fibrosis formation under inflammation.

Methods
Paraffin-embedded specimens of the colon from patients with CD undergoing surgery were obtained for Masson staining and IL-22 immunohistochemistry. In vivo, male C57B6/J mice aged 8 weeks were divided into the DSS group, DSS+IL-22 group, and control group. The two DSS groups were fed with 2% DSS for 7 days and distilled water for 14 days, repeating three times. Mice were given rIL-22 (200 ng/mouse) or phosphate-buffered saline intraperitoneally at 0, 2, 4, and 6 days after DSS administration. Colonic bacterial 16S rRNA gene sequencing assay and RNA sequencing of colon tissue were performed. In vitro, the DLD-1 cells were stimulated by LPS and treated with different gradients of rIL-22 before the scratch wound-healing migration assay.

Results
A positive correlation between IL-22 expression and Masson staining area was observed in the surgical specimen from CD patients (R2=0.7473) and IL-22 expression was higher in CD patients with intestinal stricture. In animal experiments, the colonic fibrosis model was successfully created and confirmed by Masson’s staining. Notably, the DSS+IL-22 group exhibited a slightly shortened colon length, greater weight reduction, and higher histopathology score than the DSS group at sacrifice. The injection of rIL-22 restored colonic microbiota abundance, notably by reducing Clostridium-sensu-stricto-1 and increasing Lachnospiraceae_NK4A136 and Turicibacter. A total of 278 genes were differentially expressed in the DSS+rIL-22 vs DSS group. We figured out that the 48 upregulated genes were mainly enriched in extracellular function, muscle contraction, and biosynthesis. The 230 downregulated genes were mainly enriched in immune response and pathway response to pathogens. The further immunoinfiltration analysis showed increased aggregation of marginal zone B cells but less infiltrated innate lymphoid cell group 1, natural killer T cell, and effector memory T cell after DSS treatment. In vitro, with longer stimulation time, the higher dose of rIL-22 induced a greater percentage of wound healing under LPS-induced inflammation.

Conclusion
We primarily revealed the potential positive correlation between IL-22 and colonic fibrosis from several aspects. The underlying mechanisms may be related to the influence on microbiota abundance classical pro-inflammatory pathways like TNF pathway and NLR pathway, immune cells or pericytes.
P162 The Biosimilar Switch: IBD nurse's experience in Our Lady of Lourdes Hospital
Authors: McMahon S 
Published: January 2024

Abstract

Background
A biological medication contains an active substance that is produced from a biological source such as living cells, hormones or enzymes. The active substance in a biological medicine is what makes the medicine work. Biological medicines are also called biologics. A biosimilar medicine is a biological medicine that is developed to be highly similar to an existing biologic but they are not identical and so cannot be considered to be generics. Biosimilars were introduced in Ireland in 2014. In 2018, Our Lady of Lourdes Hospital commenced a procurement programme to decide which Infliximab biosimilar to switch our patients to. This process would allow for a huge cost-saving to the hospital budget and also allowed for the allocation of a whole-time clinical nurse specialist to add the IBD nursing team. The infliximab biological switch was then carried out starting in October 2019.
All patients received a letter explaining the switch and a booklet to explain the meaning of biosimilars. The patients were then either phoned or spoken to in person by either the IBD nurse or a GI pharmacist, and any questions or concerns addressed.

Methods
A patient satisfaction survey was sent to each patient 6 months after the switch. Each questionnaire was sent with a prepaid return envelope. The questionnaire consisted of 7 questions with tick box answers.
1. Gender?
2. Age?
3. Did you receive a letter and information booklet in the post prior to the day of your infusion switch.
4. Did you get the opportunity to talk to someone on the phone prior to your infusion?
5. Did you get the opportunity to speak to a nurse or pharmacist on the day of your infusion? If so who?
6. Were you given a named person to contact if you had any issues after our first infusion?
7. Were you happy with the overall experience of the infliximab biosimilar switch?

Results
86 patients were switched from the originator to the biosimilar Flixabi. 22 responses were received.
1. 11 male; 11 female
2. Age 16-19 - 2; 20-29 - 1; 30-39 - 4; 40-49 - 4; 50-59 - 9; 70-79 - 1; preferred not to answer - 1.
3. 20 received the letter and booklet; 2 did not.
4. 15 spoke to someone on the phone; 6 did not and 1 could not remember.
5. 22 - spoke to a nurse; 0 - pharmacist.
6. 20 - yes; 2 - no.
7. 21 - yes; 1 - unsure.

Conclusion
Of the 86 patients who were switched 22 responded to the questionnaire. 21 patients were happy with their overall experience with how the switch was conducted.
P175 HucMSC-Exo ameliorate experimental colitis via modulating gut microbiota and metabolites
Authors: Wang C , Wang D , Luo Y , Guo J , Ma Z , Liang X , Sun D , Li C , Zhang X 
Published: January 2024

Abstract

Background
Gut microbiota and metabolites have been shown to influence the development of inflammatory bowel disease (IBD). Exosomes derived from human umbilical cord mesenchymal stem cells (HucMSC-Exo) have been identified as a promising biological therapy for the treatment of IBD. Previous studies have described that HucMSC-Exo could modulate gut microbiota. However, the mechanism remains unclear. Here, we explored the role of gut microbiota and metabolites in HucMSC-Exo-mediated amelioration of experimental colitis.

Methods
Dextran sulfate sodium (DSS) was used to induce colitis. The role of HucMSC-Exo were assessed in colitis mice. Fecal microbiota transplantation (FMT) and sterile fecal filtrate gavage were employed to evaluate the effect of gut microbiota and metabolites. Gut microbiota and metabolites were analyzed through 16S rRNA sequencing and metabolomic profiling. The proportion of CD4+ T cells were phenotyped by multicolour flow cytometry.

Results
HucMSC-Exo treatment alleviated colon inflammation by regulating flora composition, significantly up-regulated the levels of bacteria such as Bacteroides, Parabacteroides distasonis, and Tannerellaceae. Meanwhile, HucMSC-Exo transformed metabolite short-chain fatty acid (SCFA) profiles, particularly increased butyrate level. Additionally, HucMSC-Exo selectively up-regulated the frequencies of regulatory T (Treg) cells as well as down-regulated the ratio of T helper type 17 (Th17) cells in colonic lamina propria to maintain intestinal immune homeostasis and repaired the colonic mucus barrier. FMT and sterile fecal filtrate gavage were conducted to confirm the above mechanism. Microbiota from HucMSC-Exo-treated mice alleviated the colitis over microbiota from DSS-treated mice. Sterile fecal filtrate from HucMSC-Exo-treated mice and butyrate induced similar beneficial outcomes, such as improved the Th17/Treg balance and repaired the colonic mucus barrier. Collectively, HucMSC-Exo ameliorate colitis by directly modulating gut microbiota and metabolites.

Conclusion
HucMSC-Exo ameliorated experimental colitis via directly modulating gut microbiota and metabolite butyrate, which could regulate CD4+T cells homeostasis and repair colonic mucus barrier. The findings demonstrated the HucMSC-Exo as a potential gut microbiota and metabolites modulator to treat IBD.