bluuebunny/crossref_metadata_2025 huggingface dataset:
Genital Self-Image and Aesthetic Genital Surgeries: Novel Perspectives Across the Cisgender and Transgender Spectrum
Authors: Sharp Gemma
Published: July 2021

Genital-focused body image concerns or negative genital self-image are a common experience across the gender spectrum, including among cisgender and transgender populations. Such concerns can result in lower psychological and sexual well-being. In this article, it is proposed that the development of genital self-image concerns may be partly explained by the theoretical framework of cisgenderism. This theory proposes that there are only 2 genders—men and women—and these are dictated solely by the appearance of the genitals. Any deviation from these 2 categories can result in discrimination, which particularly impacts transgender individuals. An increasing number of cisgender and transgender people are seeking out aesthetic genital procedures to alleviate genital self-image concerns (and gender dysphoria in transgender populations). The growing body of research suggests that cisgender and transgender men and women are relatively satisfied with the results of their genital procedures. However, this research is limited by a lack of standardized and validated patient-reported measures to evaluate surgical outcomes. Furthermore, despite negative genital self-image being a key motivator for surgery, it is often not included as an outcome measure. In this article, recommendations are proposed for conducting higher-quality evaluation studies of aesthetic genital procedures in cisgender and transgender populations. Moreover, future research and clinical directions are suggested to assist transgender men and women who choose not to undergo genital gender-confirming surgery. The vast majority of transgender individuals do not have this surgery and so are in great need of support in managing their gender dysphoria and negative genital self-image.
Why signal if you are not attractive? Courtship synchrony in a fiddler crab
Authors: Harrison Lauren M , Melo Gabriela C , Perez Daniela M , Backwell Patricia R Y
Published: July 2021

Synchronized male courtship signals are puzzling because males generally compete with each other for females. Male Austruca mjoebergi fiddler crabs wave in synchrony to attract females, but, all else being equal, females have a strong preference for “leader” males that can produce waves before other males (“followers”). So why do followers participate in synchrony? Here, we experimentally investigate three explanations for why followers might wave in synchrony: 1) followers obtain a small proportion of matings, 2) followers are more likely than a leader to attract females if they are positioned closer to her than is the leader, and 3) synchrony functions as a long-distance visual signal that attracts females so there is a net benefit to synchrony for all males. Using robotic male crabs, we found that females show a strong preference for leading males, but followers obtain a “better-than-nothing” proportion of mates. We also showed that closer proximity of a follower to the female did not affect her preference for leaders, although being a leader increased a male’s success when he was further from the female than were rival males. Finally, females were more likely to approach a distant group if there was a leader present, suggesting that followers do benefit from participating in synchrony.
RNF8 is not required for histone-to-protamine exchange in spermiogenesis
Authors: Abe Hironori , Meduri Rajyalakshmi , Li Ziwei , Andreassen Paul R , Namekawa Satoshi H
Published: July 2021

While an E3 ubiquitin ligase, RNF8, was initially reported to be required for histone-to-protamine exchange in spermiogenesis, we subsequently demonstrated that RNF8 is not involved in this process. Nevertheless, reflecting a lingering misunderstanding in the field, a growing number of studies have continued to postulate a requirement for RNF8 in the histone-to-protamine exchange. For example, a recent study claimed that a mouse PIWI protein, MIWI, controls RNF8-mediated histone-to-protamine exchange. Here, confirming our earlier conclusions, we show that RNF8 is required neither for the establishment of histone H4K16 acetylation, which is an initial step in histone removal during spermiogenesis, nor for the incorporation of two protamine proteins, PRM1 and PRM2. Thus, whereas RNF8 mediates ubiquitination of H2A on the sex chromosomes in meiosis, during the prior stage of spermatogenesis, our genetic evidence underscores that RNF8 is not involved in histone-to-protamine exchange.
Deontic Fallacies and the Arguments against Conscientious Objections
Authors: Napier Stephen
Published: July 2021

The respect for one’s conscience is rooted in a broader respect for the human person. The conscience represents a person’s ability to identify the values and goods that inform her moral identity. Ignoring or overriding a person’s conscience can lead to significant moral and emotional distress. Refusals to respect a person’s conscientious objection to cases of killing are a source of incisive distress, since judgments that it is impermissible to kill so-and-so are typically held very strongly and serve as central moral commitments in one’s moral identity. I think it is wrong for a college basketball coach to pay his players, but I think it is really wrong to kill people. This article argues that any and all arguments for not respecting a conscientious objection to abortion commit a deontic fallacy. Briefly, arguments for the permissibility of abortion are structurally such that abortion is at best permissible, not obligatory. Now, arguments to justify overriding or ignoring a person’s objection to performing action (α) must understand action (α) as being obligatory. Thus, arguments for ignoring conscientious objections to performing abortion are incongruent with the actual philosophical justifications for abortion. Such arguments, then, commit a deontic fallacy.
Treatment practices and outcomes in incident peritoneal dialysis patients: the Swedish Renal Registry 2006–2015
Authors: Xu Hong , Lindholm Bengt , Lundström Ulrika Hahn , Heimbürger Olof , Stendahl Maria , Rydell Helena , Segelmark Mårten , Carrero Juan-Jesus , Evans Marie
Published: July 2021

Background

Therapeutic developments have contributed to markedly improved clinical outcomes in peritoneal dialysis (PD) during the 1990s and 2000s. We investigated whether recent advances in PD treatment are implemented in routine Swedish care and whether their implementation parallels improved patient outcomes.

Methods

We conducted an observational study of 3122 patients initiating PD in Sweden from 2006 to 2015. We evaluated trends of treatment practices (medications, PD-related procedures) and outcomes [patient survival, major adverse cardiovascular events (MACEs), peritonitis, transfer to haemodialysis (HD) and kidney transplantation] and analysed associations of changes of treatment practices with changes in outcomes.

Results

Over the 10-year period, demographics (mean age 63 years, 33% women) and comorbidities remained essentially stable. There were changes in clinical characteristics (body mass index and diastolic blood pressure increased), prescribed drugs (calcium channel blockers, non-calcium phosphate binders and cinacalcet increased and the use of renin–angiotensin system inhibitors, erythropoietin and iron decreased) and dialysis treatment (increased use of automated PD, icodextrin and assisted PD). The standardized 1- and 2-year mortality and MACE risk did not change over the period. Compared with the general population, the risk of 1-year mortality was 4.1 times higher in 2006–2007 and remained stable throughout follow-up. However, the standardized 1- and 2-year peritonitis rate decreased and the incidence of kidney transplantation increased while transfers to HD did not change.

Conclusions

Over the last decade, treatment advances in PD patients were accompanied by a substantial decline in peritonitis frequency and an increased rate of kidney transplantations, while 1- and 2-year survival and MACE risk did not change.
Evaluation of the preventive effect of two concentrations of xylitol varnish versus fluoride varnish on enamel demineralization around orthodontic brackets: a randomized controlled trial
Authors: Zarif Najafi Hooman , Shavakhi Mojgan , Pakshir Hamid Reza
Published: July 2021

Background

The highly prevalent white spot lesions around orthodontic brackets necessitate introducing preventive materials without relying on patient compliance.

Objective

To evaluate the antidemineralizing effect of two concentrations of xylitol varnish.

Trial design

Triple-blind, four-arm, parallel-group, single-center, randomized controlled clinical trial.

Methods

A total of 120 orthodontic patients were randomly assigned to four groups (n = 30), using a computer-generated randomized block list. The treatment groups were: 10% xylitol, 20% xylitol, 5% fluoride, and placebo. Tooth demineralization was measured with DIAGNOdent at T1 (before treatment), followed by varnish application. At T2 (third month), the varnish was re-applied, and at the third (T2) and sixth (T3) months, and after treatment (T4), the demineralization was measured. The white spot lesion frequency was assessed visually after treatment. The participants, the clinician, and data assessors were all blinded to group assignments.

Results

A total of 115 patients underwent per-protocol analyses. At T2, the mean DIAGNOdent numbers in the fluoride and 10% xylitol groups were significantly lower than the placebo group (P = 0.00), with a mean difference of 0.63 (95% CI, 0.15–1.10) and 0.5 (95% CI, 0.04–0.95), respectively. At T3, the fluoride and 10% xylitol groups had significantly lower mineral loss than the placebo group (P=0.046) with a mean difference of 0.52 (95% CI, 0.14–0.89) in the fluoride and 0.45 (95% CI, 0.03–0.86) in the 10% xylitol groups, respectively. However, at T4, only the mean for the 10% xylitol group was significantly different (P=0.049) from the placebo group, with a mean difference of 1.18 (95% CI, 0.42–1.93). Visual assessment showed that after treatment, the prevalence of white spot lesions in the fluoride (P=0.03) and 10% xylitol (P=0.00) groups was less than the placebo group with the odds ratio of 0.67 (95% CI, 0.46–0.96) and 0.43 (95% CI, 0.28–0.64), respectively.

Conclusion

The 10% xylitol varnish short-term effects on caries control were significantly greater than 20% xylitol varnish and placebo but similar to fluoride varnish. However, the 10% xylitol long-term effect was almost better than fluoride varnish.

Trial registration

The protocol was registered at IRCT.ir under the code IRCT20180913041032N1.
Guadagni in Handel’s London: the formation of a voice
Authors: Howard Patricia
Published: July 2021

Guadagni’s first visit to London spanned seven years, from the autumn of 1748 to summer 1755. He arrived from the Veneto as an inexperienced singer at the outset of his career, having been expelled from the Cappella di Sant’ Antonio in Padua after a mere six months’ employment, and, in the subsequent season, taken a couple of ‘third man’ roles in an undistinguished opera company. In London he quickly developed his career, securing leading roles in Crosa’s touring opera buffa company and appearing regularly in concerts both in London and in provincial festivals. But by far the most significant activity was his contribution, from 1750, to Handel’s oratorio series. For six Lenten seasons, Handel’s music dominated Guadagni’s repertory, both in London and in Dublin. Although Handel created only two roles specifically for him, he adapted many others to suit his voice, with Guadagni taking over either those originally written for female voices, including the contralto Susanna Cibber and the mezzo-soprano Giulia Galli, or those which had been performed by his fellow castratos Andreoni and Senesino; in addition, his concert repertory included solos and duets taken from Handel’s operas and oratorios. Having arrived in England a raw and untested novice, Guadagni left an accomplished soloist, going on to take ‘first man’ roles throughout Europe. This article examines the music written for, assigned to and chosen by Guadagni, to trace the part played by Handel’s music in forming the singer at the outset of his career, and argues that Handel was, in his turn, well served by Guadagni’s distinctive vocal talents.
Frailty and cardiovascular outcomes in the National Health and Aging Trends Study
Authors: Damluji Abdulla A , Chung Shang-En , Xue Qian-Li , Hasan Rani K , Moscucci Mauro , Forman Daniel E , Bandeen-Roche Karen , Batchelor Wayne , Walston Jeremy D , Resar Jon R , Gerstenblith Gary
Published: July 2021

Aims

Physical frailty is a commonly encountered geriatric syndrome among older adults without coronary heart disease (CHD). The impact of frailty on the incidence of long-term cardiovascular outcomes is not known.We aimed to evaluate the long-term association of frailty, measured by the Fried frailty phenotype, with all-cause-mortality and MACE among older adults without a history of CHD at baseline in the National Health and Aging Trends Study.

Methods and Results

We used the National Health and Aging Trends Study, a prospective cohort study linked to a Medicare sample. Participants with a prior history of CHD were excluded. Frailty was measured during the baseline visit using the Fried physical frailty phenotype. Cardiovascular outcomes were assessed during a 6-year follow-up.

Of the 4656 study participants, 3259 (70%) had no history of CHD 1 year prior to their baseline visit. Compared to those without frailty, subjects with frailty were older (mean age 82.1 vs. 75.1 years, P < 0.001), more likely to be female (68.3% vs. 54.9%, P < 0.001), and belong to an ethnic minority. The prevalence of hypertension, falls, disability, anxiety/depression, and multimorbidity was much higher in the frail and pre-frail than the non-frail participants. In a Cox time-to-event multivariable model and during 6-year follow-up, the incidences of death and of each individual cardiovascular outcomes were all significantly higher in the frail than in the non-frail patients including major adverse cardiovascular event (MACE) [hazard ratio (HR) 1.77, 95% confidence interval (CI) 1.53, 2.06], death (HR 2.70, 95% CI 2.16, 3.38), acute myocardial infarction (HR 1.95, 95% CI 1.31, 2.90), stroke (HR 1.71, 95% CI 1.34, 2.17), peripheral vascular disease (HR 1.80, 95% CI 1.44, 2.27), and coronary artery disease (HR 1.35, 95% CI 1.11, 1.65).

Conclusion

In patients without CHD, frailty is a risk factor for the development of MACEs. Efforts to identify frailty in patients without CHD and interventions to limit or reverse frailty status are needed and, if successful, may limit subsequent adverse cardiovascular events.
Medical therapies for prevention of cardiovascular and renal events in patients with atrial fibrillation and diabetes mellitus
Authors: Fauchier Laurent , Boriani Giuseppe , de Groot Joris R , Kreutz Reinhold , Rossing Peter , Camm A John
Published: July 2021

Atrial fibrillation (AF), type 2 diabetes mellitus (DM), and chronic kidney disease (CKD) are three global epidemics with significant effects on morbidity and mortality. Diabetes is a risk factor for AF, and a risk factor for thromboembolism, comorbidity, and mortality when AF is present. The pathophysiology of diabetes-related AF and interrelationships with cardiovascular events and renal events is not fully understood but is in part related to structural, electrical, electromechanical, and autonomic remodelling. The current practice guidelines offer limited recommendations on the management of patients with AF (or risk of AF) and diabetes with its own heterogeneity for the prevention of cardiovascular and renal events. This document discusses possible clinical approaches for these patients. In the last decade, there have been major improvements for the prevention of stroke in AF patients with direct oral anticoagulants, which are preferable to vitamin K antagonists for stroke prevention in DM. Because of the increased risk rate for several cardiovascular adverse events in diabetic patients, a similar relative risk reduction generally translates into greater absolute risk reduction in the diabetic population. Recent trials with non-insulin diabetes drugs using glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors showed a significant reduction for the risk of major adverse cardiovascular events in patients with type 2 DM. Sodium-glucose cotransporter-2 inhibitors also showed a large reduction in hospitalization for heart failure and renal events, which need to be more completely evaluated in patients with AF. Mechanisms, risks, and optimal management of AF patients with DM who have or are under risk of developing heart failure or CKD are also discussed in this document. The benefits of medical therapies for these patients still need to be put into perspective, and gaps in evidence on some of these issues are likely to be addressed in future years.
Early onset atrial lesions in a patient with a novel LMNA frameshift mutation
Authors: Lin Yongping , Liu Hailei , Cui Chang , Lin Zhiqiao , Zhang Yike , Zhu Yue , Ju Weizhu , Chen Minglong
Published: July 2021

Genetic mutations in the lamin A/C gene (LMNA) have been linked to cardiomyopathy. Different mutational sites exhibit different clinical manifestations and prognoses. Herein, we identified a novel LMNA frameshift mutation, p.P485Tfs*67, from a patient with early-onset atrial disease. To verify the pathogenicity of this variation, a transgenic zebrafish model was constructed, which demonstrated that adult zebrafish with the LMNA mutation showed an abnormal ECG and impaired myocardial structure. Our study suggests the atrial pathogenicity of the LMNA-P485Tfs mutation, which is helpful to understand the function of the Ig-like domain of lamin A/C.
Transnational identity and the Gulf crisis: changing narratives of belonging in Qatar
Authors: Mitchell Jocelyn Sage
Published: July 2021

What does the recent Gulf diplomatic crisis of June 2017 to January 2021 mean for the future of the region's signature transnationalism: the khalījī [Gulf] identity? This identity narrative encompasses the shared sociocultural backgrounds of the people of the region, but the unprecedented separations, caused by the regional crisis, may have shifted the discourse of belonging in the Gulf. To investigate the impact of the recent crisis on regional identity narratives, this article explores the new National Museum of Qatar's presentation of Qatar's political history from 1848 to 1868, as well as museum-goers' reactions to this presentation, through original fieldwork and ethnographic interviews with Qatari and expatriate residents. The analysis highlights the museum's purposeful portrayal of parallels between intra-Gulf conflicts of the past and the recent crisis, a presentational choice that stands in sharp contrast to previous regional norms of tactful diplomacy. Further, museum-goers recognized the linguistic and symbolic parallels, provoking both engagement with and rejection of the concept of khalījī identity. In summary, this analysis suggests that the crisis has shifted the norms of discourse in the region in ways that may make social reconciliation difficult, even as political bonds resume. As the region moves forward from crisis, policy-makers should reduce the tension between national and transnational identity narratives by creating space for the renewal of khalījī ties.
Turkish foreign policy in the Middle East: power projection and post-ideological politics
Authors: Dalacoura Katerina
Published: July 2021

Power projection, security, pragmatic considerations and a disparate mix of national interests and narrower party-political objectives have driven the foreign policy of Turkey's Justice and Development Party (AKP) in the Middle East since it came to power in 2002. Ideological concerns, consisting of a fluid blend of Islamist, neo-Ottoman and ‘civilizationalist’ ideas, mingled with a hefty dose of Turkish nationalism, have played a variable, auxiliary but none the less significant role. The Arab uprisings of 2011 opened up opportunities for the AKP to pursue its ideological objectives and they became more central to its policies, if only in some areas or clusters of relationships. However, they receded after 2015, when a confluence of domestic and regional factors caused the onset of a transactional, ‘post-ideological’ phase. The article places the Middle East in the wider context of Turkish foreign policy, both historically and in comparison with other regions, arguing in the process that categories of ‘East’ and ‘West’ are of limited value for its proper understanding and interpretation. It then divides it into four sub-regions, distinct in geographical and issue terms: Syria and Iraq (the ‘near abroad’), the wider Arab world, Israel–Palestine, and Iran. It analyses Turkish foreign policy towards them in sequence, illustrating the ways in which power-political considerations have predominated in all, albeit in different ways and to varying degrees, over the past five years.
Bahrain's transnational Arab Spring: repression, oil and human rights activism
Authors: Moritz Jessie
Published: July 2021

Studies of the Middle East following the Arab Spring have concluded that ‘repression works’, especially in the oil- and gas-rich countries of the Gulf. Drawing on primary materials collected during fieldwork trips to Bahrain, the United States and Britain, this article nuances the ‘repression effect’ by tracing the emergence of a transnational Bahraini opposition, mapping the relationships and joint activities between domestic and exiled Bahraini groups, international NGOs and western policy-makers. It finds that even in the context of domestic repression and continuing ideological divides within Bahrain's opposition, transnational networks have not only sustained opposition organizations, but also maintained access to foreign policy-makers, producing repeated criticisms of the Bahraini regime and legal challenges to ruling elites who visit western states. The successes of this advocacy are modest: while it has not drastically reshaped the domestic state–society relationship, it has created significant costs for the Bahraini regime and damaged Bahrain's international brand. As a result, state and opposition networks now compete for influence over western policy-makers: international ‘arenas of advocacy’—such as the UK parliament, US Congress, UNHRC and European Parliament—have now become ‘arenas of contestation’, as state and opposition narratives of Bahraini politics, filtered through western policy-makers, play out during debates over foreign policy towards Bahrain. The article positions transnational activism as a direct outcome of the ‘repression effect’, highlighting ongoing contests for influence between state and society occurring in international and transnational spaces, even as the domestic scope for opposition mobilization remains highly restricted.
Compensation Funds as a Remedial Mechanism for Victims of Corporate Pollution in Kenya: A Feasibility Study
Authors: Mwanza Rosemary
Published: July 2021

This article explores the potential of a public-run, risk-based compensation fund to provide compensation for victims of corporate pollution in Kenya. Existing remedial mechanisms are severely limited by the uncertainty of recovery attributable to doctrinal barriers in liability rules, the length of time and cost involved in settling claims and the impact of corruption as a hindrance to access to justice. Depending on their design, compensation funds could offer prompt compensation at lower personal costs to claimants. Considering that victims of corporate pollution in Kenya tend to be poor, prompt compensation can cushion their welfare by providing much-needed funds to cover medical expenses and support livelihoods. While claimants would likely obtain less compensation in absolute amounts than in tort litigation, they would still retain the right to pursue supplemental compensation through alternative mechanisms. Thus, a pragmatic approach would be to develop a compensation fund while introducing effective reforms to existing mechanisms.
Protein–lipid interplay at the neuromuscular junction
Authors: Unwin Nigel
Published: July 2021

Many new structures of membrane proteins have been determined over the last decade, yet the nature of protein–lipid interplay has received scant attention. The postsynaptic membrane of the neuromuscular junction and Torpedo electrocytes has a regular architecture, opening an opportunity to illuminate how proteins and lipids act together in a native membrane setting. Cryo electron microscopy (Cryo-EM) images show that cholesterol segregates preferentially around the constituent ion channel, the nicotinic acetylcholine receptor, interacting with specific sites in both leaflets of the bilayer. In addition to maintaining the transmembrane α-helical architecture, cholesterol forms microdomains – bridges of rigid sterol groups that link one channel to the next. This article discusses the whole protein–lipid organization of the cholinergic postsynaptic membrane, its physiological implications and how the observed details relate to our current concept of the membrane structure. I suggest that cooperative interactions, facilitated by the regular protein–lipid arrangement, help to spread channel activation into regions distant from the sites of neurotransmitter release, thereby enhancing the postsynaptic response.
Constraining the formation of NGC 1052-DF2 from its unusual globular cluster population
Authors: Trujillo-Gomez Sebastian , Kruijssen J M Diederik , Keller Benjamin W , Reina-Campos Marta
Published: July 2021

The ultra-diffuse galaxy (UDG) NGC 1052-DF2 has a low dark matter content and hosts a very unusual globular cluster (GC) population, with a median luminosity ∼4 times higher than in most galaxies and containing about 5 per cent of the galaxy’s stars. We apply a theoretical model that predicts the initial cluster mass function as a function of the galactic environment to investigate the origin of DF2’s peculiar GC system. Using the GC mass function, the model constrains the star-forming conditions in the galaxy during the formation of its GCs, ∼9 Gyr ago. We predict that the GCs formed in an environment with very high gas surface density, $\Sigma _{\rm ISM}\gtrsim 10^3\rm \,{M_\odot}\rm \,{pc}^{-2}$, and strong centrifugal support, $\Omega \gtrsim 0.7\rm \,{Myr}^{-1}$, similar to nearby circumnuclear starbursts and the central region of the Milky Way. The extreme conditions required to form the observed GC population imply a very high cluster formation efficiency of ≈87 per cent, and contrast strongly with the current diffuse nature of the galaxy. Since a nuclear starburst would lead to the rapid in-spiral of the GCs and is ruled out by the absence of a nuclear star cluster, we propose that the GCs plausibly formed during a major merger at z ∼ 1.3. The merger remnant must have undergone significant expansion of its stellar (and perhaps also its dark matter) component to reach its low present surface brightness, leading to the interesting possibility that it was the formation of DF2’s extreme GC population that caused it to become a UDG. If true, this strong structural evolution would have important implications for understanding the origins of UDGs.
Radio emission from dust-obscured galaxies
Authors: Gabányi Krisztina É , Frey Sándor , Perger Krisztina
Published: July 2021

The coevolution of galaxies and their central supermassive black holes is a subject of intense research. A class of objects, the dust-obscured galaxies (DOGs) are particularly interesting in this respect as they are thought to represent a short evolutionary phase when violent star formation activity in the host galaxy may coexist with matter accretion on to the black hole powering the active nucleus. Here, we investigate different types of DOGs classified by their mid-infrared spectral energy distributions to reveal whether they can be distinguished by their arcsec-scale radio properties. Radio emission is unaffected by dust obscuration and may originate from both star formation and an active nucleus. We analyse a large sample of 661 DOGs complied from the literature and find that only a small fraction of them (∼2 per cent) are detected with flux densities exceeding ∼1 mJy in the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey. These radio-detected objects are almost exclusively ‘power-law’ DOGs. Stacking analysis of the FIRST image cutouts centred on the positions of individually radio-undetected sources suggests that weak radio emission is present in ‘power-law’ DOGs. On the other hand, radio emission from ‘bump’ DOGs is only marginally detected in the median-stacked FIRST image.
MOMC-2. Glioblastoma Metabolic Symbiosis: When Lactate Takes The Lead
Authors: Guyon Joris , Larrieu Claire , Bouchez Cyrielle , Moncada Ignacio Fernandez , Coffe Aurelien , Nikolski Macha , Bikfalvi Andreas , Daubon Thomas
Published: July 2021

Glioblastoma (GBM) is a common and devastating brain tumor, associated with a low median survival, despite standard therapeutic management. Among its major features, GBMs are highly angiogenic and exhibit paradoxically an elevated glycolysis. Most of differentiated cells convert glucose into pyruvate that enters into the Krebs cycle to maximize energy production in the presence of oxygen. For cancer cells, glucose uptake and catabolism are increased regardless of oxygen level. However, their energy needs are important – mainly for rapid growth – that it requires a much faster production flow. It is at this step that lactate dehydrogenase (LDH) are involved: LDHA converts efficiently pyruvate into lactate and generates NAD+ to maintain glycolysis. Thus, the lactate formed is exported into the extracellular compartment inducing an unfavourable acidification of the microenvironment. Moreover, LDHB, another LDH isoform, metabolizes lactate into pyruvate for generating energy in mitochondria. Though LDHA has already been studied in many cancers including GBM, the simultaneous role of LDH enzymes have not yet been investigated in GBM development.

Hypoxia-driven LDHA expression and lactate production increased cell invasion. Infusing 13C-lactate in starved cells rescued TCA cycle. Then, we showed that, under hypoxia, double sgLDHA/B cell growth and invasion was dramatically decreased in comparison to control cells, mainly caused by an increase in apoptosis. Moreover, double impairment of LDHA and B significantly reduced tumor growth and cell invasion, and induces a massive increase in mouse survival. Tracing experiments with 13C-Glucose coupled with RNA sequencing revealed how metabolism adapts to these contraints, by modifying electron transport chain subunit expressions or by increasing lipid droplet formation.

Considered for a long time as a metabolic waste, lactate is shown here to play a critical role in GBM cell symbiosis. This study highlighted GBM adaptability through the LDH isoforms and their involvement in GBM development.
OPTC-2. Identification of enriched genes and pathways associated to hypoxia induced migration in patient-derived glioma stem cell lines by RNAseq
Authors: Hanon Olivia Morris , Mahmoud Yamil , Vera Mariana , Girotti Romina , Rabinovich Gabriel , Sevlever Gustavo , Scassa Maria Elida , Richardson Guillermo Videla
Published: July 2021

Glioblastomas (GBM), the most prevalent and lethal primary brain tumors, are characterized by high intertumoral heterogeneity, diffuse infiltration, and resistance to conventional therapies. Notably, the ability of tumor cells to invade surrounding tissues is one of their most damaging characteristics, it not only causes resistance to therapies such as surgery and radiotherapy but is ultimately the primary cause of death. Therapies that cause hypoxia (e.g. anti-angiogenic therapies) have been shown to increase invasiveness, leading to resistance to the therapy itself and further complications for the patients. Using patient-derived glioma stem cell lines (GSCL) we have discovered cell lines that display heterogeneous migratory behavior in response to hypoxia. As expected we observed that four GSCLs studied had increased migration in hypoxia. Strikingly, two other cell lines studied showed decreased migration in hypoxia. This unforeseen result reflects the heterogeneous nature of GBM and the difference between these GSCLs could be key to understanding this variable. To delve into the molecular context that could explain these differences we performed an exploratory RNAseq analysis on four of the GSCLs, two that showed hypoxia-induced migration and two with decreased migration in hypoxia, and evaluated genes differentially expressed in hypoxia versus normoxia. We also carried out gene ontology and pathway enrichment analysis to discover molecular and pathway patterns consistent with the migratory behaviors observed in each group of GSCLs. The results show how that a similar migratory response to hypoxia coincides with particular sets of enriched genes and pathways. Specifically, we found NOTCH and WNT signaling pathways upregulated in GSCLs which showed increased migration in hypoxia while the IFN-gamma pathway upregulated in GSCLs with decreased migration in hypoxia. Knowing the individual molecular mechanisms responsible for the migratory behavior could allow for tailor-made therapies that reduce the dissemination of these tumors.
OMRT-3. Longitudinal analysis of diffuse glioma reveals cell state dynamics at recurrence associated with changes in genetics and the microenvironment
Authors: Varn Frederick , Johnson Kevin , Barthel Floris , Kim Hoon , Wade Taylor , Malta Tathiane , Sabedot Thais , Lodha Disha , Ajaib Shoaib , Ahmed Nazia , Garofano Luciano , D’Angelo Fulvio , Stead Lucy , Poisson Laila , Noushmehr Houtan , Iavarone Antonio , Verhaak Roel ,   GLASS Consortium
Published: July 2021

Diffuse glioma is an aggressive brain cancer that is characterized by a poor prognosis and a universal resistance to therapy. The evolutionary processes behind this resistance remain unclear. Previous studies by the Glioma Longitudinal Analysis (GLASS) Consortium have indicated that therapy-induced selective pressures shape the genetic evolution of glioma in a stochastic manner. However, single-cell studies have revealed that malignant glioma cells are highly plastic and transition their cell state in response to diverse challenges, including changes in the microenvironment and the administration of standard-of-care therapy. Interactions between these factors remain poorly understood, making it difficult to predict how a patient’s tumor will evolve from diagnosis to recurrence. To interrogate the factors driving therapy resistance in diffuse glioma, we collected and analyzed RNA- and/or DNA-sequencing data from temporally separated tumor pairs of 292 adult patients with IDH-wild-type or IDH-mutant glioma. Recurrent tumors exhibited diverse changes that were attributable to changes in anatomic composition, somatic alterations, and microenvironment interactions. Hypermutation and acquired CDKN2A homozygous deletions associated with an increase in proliferating stem-like malignant cells at recurrence in both glioma subtypes, reflecting active tumor expansion. IDH-wild-type tumors were more invasive at recurrence, and their malignant cells exhibited increased expression of neuronal signaling programs that reflected a possible role for neuronal interactions in promoting glioma progression. Mesenchymal transition was associated with the presence of a specific myeloid cell state defined by unique ligand-receptor interactions with malignant cells, providing opportunities to target this transition through therapy. Collectively, our results uncover recurrence-associated changes in genetics and the microenvironment that can be targeted to shape disease progression following initial diagnosis.
OTEH-5. Characterization of long-non coding RNA associated ceRNA network hub gene involved in glioblastoma multiforme lipid metabolism
Authors: Rizalhanafi Fatin Nabihah , Ramli Norlisah , Narayanan Vairavan , Rashid Khairunnisa , Singh Jesminder Kaur , Ibrahim Kamariah
Published: July 2021

Background

Glioblastoma multiforme (GBM) are the major death contributor in primary brain tumour. Despite having an improved diagnostic criterion by integrating both histological and molecular features such as Isocitrate Dehydrogenase (IDH) detection, the prognosis of GBM patients still remain poor. Lipid metabolism is an essential pathway that fuel GBM aggressiveness. IDH1 one of the key enzyme that regulates it. Long non-coding RNAs (lncRNAs) act as competing endogenous RNAs (ceRNAs) in tumour initiation and progression. In parallel, miRNA-mediate ceRNA crosstalk between lncRNAs and mRNAs. In this study, we aim to investigate the IDH1 subgroup lncRNA associated ceRNA network hub gene responsible in the coordination of glioblastoma multiforme lipid metabolism using bioinformatics approach.

Methods

TCGA-GBM dataset consist of 168 GBM RNA-seq (159 IDH1 wt and 9 IDH1 mutation) were downloaded. Differentially expressed genes (DEG) were then obtained using Limma. Gene sets related with lipid metabolism from GSEA-MSigDB were overlapped with DEG using Venn diagram to identify the DEmRNA that are related with lipid metabolism. Construction of mRNA-miRNA and lncRNA-miRNA interaction networks were performed using miRNet. The ceRNA interaction network were later combined in the Cytoscape software. Potential lncRNA hub genes were identified by CytoHubba analysis.

Results

From 1389 DEG, 67 genes were identified to be significant in the regulation of lipid metabolism. By analysing the lncRNA-miRNA-mRNA interaction network, candidate hub lncRNAs consists of three genes with highest connective nodes; CYTOR, LOXL1-AS1 and HOTAIR. These genes are significantly upregulated in glioma. LOXL1-AS1 serve as an excellent prognostic biomarker for both glioma and glioblastoma as the effect of high and low LOXL1-AS1 expression on patients’ survival is significant (p<0.05).

Conclusions

Data mining and bioinformatics approach guided the identification of the potential hub lncRNAs associated ceRNA network in GBM lipid metabolism. This allows us to uncover the novel role of lncRNA in GBM tumorigenesis.
OTEH-9. scRNA sequencing of proneural GBM avatar model reveals acquisition of oncogenic transcriptional programming and infers a developmental path towards a genomically unstable state
Authors: Taylor Brett M , Chaim Isaac A , Koga Tomoyuki , Miki Shunichiro , Yee Brian E , Yeo Gene W , Furnari Frank B
Published: July 2021

Glioblastomas (GBMs) are the most common malignant primary brain tumors, and the paucity of novel treatments warrants an investigation of its origins and development into aggressive, lethal tumors. Koga & Chaim et al. have recently shown that human pluripotent stem cells (hiPSCs) with different combinations of driver mutations can be differentiated into neural progenitor cells (NPCs) and engrafted into mice to form high grade gliomas (iHGGs). In this work, scRNA seq analysis was used to investigate the development of TP53−/−;PDGFRAΔ8–9 iHGGs, an avatar model that has been shown to recapitulate the proneural subtype of GBM. After re-engrafting the primary avatar cultures (secondary tumor stage), the TP53−/−;PDGFRAΔ8–9 iHGGs developed diverse transcriptional programming and acquired a subpopulation of cells with high expression of known GBM oncogenes, such as MYC, CDK4, and PDGFRA. Notably, when all datasets were aggregated, this oncogene amplifying transcriptional program became the largest source of variation between all stages and replicates of the TP53−/−;PDGFRAΔ8–9 iHGGs. Indicated by a larger total copy number variation (CNV), this oncogene-amplifying program was associated with a genomically unstable developmental state. Trajectory inference could track the development of this population from the initial primary culture of TP53−/−;PDGFRAΔ8–9 iHGG. Differential gene expression analysis identified distinct divergences in clonal evolution––e.g., high expression of the S100 protein family in one cluster––following the acquisition of this genomically unstable state. Lastly, genomic PCR was used to ascertain whether these changes in transcriptional programming were reflected in changes in DNA copy number and identified DNA amplifications of MYC and CDK4. Our scRNA seq analysis of the GBM avatar model platform provides novel insight into how oncogenic states in GBM develop from a small number of driver mutations.
OTEH-10. Evolutionary trajectory of epigenomic of gliomas
Authors: Malta Tathiane , Sabedot Thais , Datta Indrani , Varn Frederick , Castro AnaValeria , Garofano Luciano ,   GLASS Consortium, Verhaak Roel , Iavarone Antonio , Poisson Laila , Noushmehr Houtan
Published: July 2021

Gliomas are the most common malignant brain tumor, have an aggressive behavior, and invariably relapse and progress. Despite the recent advancements, little is known about the role of the epigenome in glioma disease progression and recurrence. To investigate the molecular dynamics over time and in response to therapeutic pressures, the Glioma Longitudinal AnalySiS (GLASS) Consortium, a multinational collaboration, is investigating epigenome-wide molecular data from primary and recurrent matched pairs, including IDH mutant (IDHmut) and IDH wildtype (IDHwt) gliomas. We have compiled a total of 357 samples comprising 143 primary-recurrent pairs profiled by DNA methylation, of which 157 samples have genomic data (WXS/WGS) and 120 have transcriptomic data (RNAseq). IDHwt gliomas have a distinct epigenetic evolution compared to IDHmut after treatment. IDHwt gliomas are more epigenetically stable over time, while IDHmut gliomas display a loss of DNA methylation throughout disease progression. Next, we investigated the molecular drivers of longitudinal gliomas by integration of DNA methylation and gene expression data. We identified epigenetic activation of cell cycle pathways in recurrent IDHmut compared to initial tumors. Transcription factors musculin, ZNF367, and ZNF682 are enriched among recurrent IDHmut gliomas and potentially regulate IDHmut recurrence and/or progression. We next used a DNA methylation-based deconvolution approach to estimate the tumor microenvironment (TME) composition. We found that the TME among IDHmut subtypes (Codel, GCIMP-high, and GCIMP-low) presented less immune infiltration than IDHwt (Classic-like, Mesenchymal-like, and PA-like). Post-treatment, we found a decrease of CD4+T and an increase of CD8+T cells in IDHmut. In conclusion, IDHmut gliomas present a more unstable epigenome, while the epigenome of IDHwt gliomas seems relatively preserved after treatment. We identified potential master regulators of cell cycle deregulation of IDHmut recurrence. Finally, the TME differs across IDHmut and IDHwt gliomas and the cell composition changes over time.
OTME-3. Dissection of the role of stromal microenvironment and tumor-TME crosstalk in pediatric brain cancer
Authors: Federico Aniello , Kool Marcel
Published: July 2021

Brain tumors are the deadliest malignancies that occur during childhood and strong efforts are required to develop innovative therapeutic strategies. The intrinsic capacity of malignant cells to organize, shape and exploit the surrounding environment where they develop (tumor microenvironment, TME), has not been fully elucidated for pediatric brain cancers yet. Here, we exploited a multi-omic approach to define the TME cell populations and their contributions in the most common pediatric brain tumor entities, such as medulloblastomas and ependymomas. Analysis of single-cell RNA sequencing data of human tumors resulted in the identification of heterogeneous populations of non-malignant cells present in the TME. In particular, re-clustering and marker-based cell type assignment strategies allowed to define a broad range of immune and stromal subclasses showing distinctive expression signatures reflecting variegated functional roles. By cross-matching the tumor data with normal brain expression atlases, we could further refine the annotation of the newly identified stromal functional subpopulations and define the “tumor-associated” marker signatures of genes exclusively enriched in stromal cells within the TME, linked to immune activation, cell adhesion and cytokine regulation pathways. Bulk transcriptomic data of human tumors and matching patient-derived xenografts (PDXs) showed that a group of secreted stromal factors acting as regulators of tumorigenic mechanisms, such as IGF2 and COL4A1, are lost after xenografting and replaced by the host murine microenvironment, suggesting that tumor cells are involved in paracrine and bivalent crosstalk with TME cells, impacting on tumor cell growth and progression. Finally, bulk deconvolution and cell-cell communication analysis were exploited to define, respectively, the stromal cell proportions and the key factors involved in the tumor-TME crosstalk; this latter can be considered as possible targets for tailored and more specific anti-tumor therapeutic strategies.
OTME-17. Single cell characterization of the immune microenvironment of melanoma brain and leptomeningeal metastases
Authors: Smalley Inna , Chen Zhihua , Phadke Manali , Li Jiannong , Yu Xiaoqing , Wyatt Clayton , Evernden Brittany , Messina Jane , Sarnaik Amod , Sondak Vernon , Zhang Chaomei , Law Vincent , Tran Nam , Etame Arnold , Macaulay Robert , Eroglu Zeynep , Forsyth Peter , Rodriguez Paulo , Chen Ann , Smalley Keiran
Published: July 2021

Melanoma brain metastases (MBM) and leptomeningeal metastases (LMM) are two manifestations of melanoma dissemination to the CNS with vastly different survival outcomes. Analysis of single cell RNA-Seq data from 43 clinical specimens has uncovered a distinct, immune-suppressed T cell landscape in the LMM microenvironment that is distinct to those of the brain and skin metastases. An LMM patient with an extraordinarily long survival and documented response to therapy demonstrated an immune repertoire that was distinct from those of typical poor survivors and more similar to CSF from non-LMM donors. Analysis of serial specimens over the course of therapy demonstrated reductions in melanoma cells and macrophages, coupled with increased levels of T cells and dendritic cells in the CSF of the extraordinary responder, whereas poor survivors showed no improvement in T cell responses. In MBM patients, targeted therapy and immunotherapy was associated with increased immune infiltrate, with similar T cell transcriptional diversity noted between skin metastases and MBM - suggestive of immune cell trafficking into the brain. Treatment with targeted therapy was associated with an enrichment of CD8 T cells. Immunotherapy was associated with a more diverse lymphocyte landscape and higher numbers of antibody-producing cells. These findings were confirmed by multiplexed staining of patient specimens and using an immune-competent mouse model of MBM. Correlation analysis across the entire immune landscape identified the presence of a rare, novel population of dendritic cells (DC3s) to be correlated with increased overall survival, regardless of disease site/treatment. The presence of DC3s positively regulated the immune environment of both patient samples and preclinical melanoma models through modulation of activated T cells and MHC expression in the tumor. Our study provides the first comprehensive atlas of two distinct sites of melanoma CNS metastases and identifies rare populations of cells that underlie the biology of this devastating disease.