Biology subjects

May, S.

Publications and source records attributed to May, S..

10 recordsLinked to original sources

bioRxiv2026

Preclinical efficacy and safety of Tegavivint in Wnt-activated hepatocellular carcinoma

Background & AimsHepatocellular carcinoma (HCC), a predominant form of liver cancer, remains a significant clinical unmet need. Given that 30-50% of HCC cases harbour mutations in the Wnt/{beta}-catenin signalling pathway, targeting this cascade represents a promising therapeutic strategy. However, the clinical translation of Wnt inhibitors has been hindered by severe adverse events observed in preclinical models and early-phase clinical trials, primarily due to the essential role of Wnt signalling in maintaining normal tissues such as the intestine and bone. MethodsWe examined the efficacy of Tegavivint, a first-in-class Wnt pathway inhibitor that targets TBL1, against HCC to elucidate its underlying mechanism of action. We evaluated the dose-response of Tegavivint and its effects on the cell cycle, apoptosis, and Wnt target gene expression using HepG2, HUH6, and HUH7 cell lines in vitro. Furthermore, we employed an orthotopic xenograft transplant model using HepG2 cells in immunodeficient mice to assess the safety profile and on-target anti-cancer efficacy of Tegavivint in vivo. ResultsTegavivint exhibited potent Wnt pathway-suppressing effects in cancer cells with constitutive Wnt pathway activation. Notably, Tegavivint displayed robust anti-tumour activity across a broad range of HCC cell lines, regardless of their Wnt pathway activation status. While Tegavivint inhibited the Wnt pathway and triggered the activation of apoptotic pathways in most cell lines, our findings suggest that it also can induce cell death by activating alternative non-apoptotic pathways in apoptosis-resistant cancer cells. In an orthotopic transplant mouse model, Tegavivint significantly downregulated Wnt pathway target genes, inhibited cell proliferation, induced apoptosis and suppressed growth in tumours. ConclusionsTaken together, our data establish a robust foundation for evaluating Tegavivint as a novel therapeutic option, specifically tailored for HCC patients harbouring Wnt-driven hepatic malignancies.

cancer biology↗

bioRxiv2026

L-pentahomoserine correlates with therapy outcome in esophageal cancer and promotes metabolic adaptations that support cell survival under nutrient-deprived conditions

Esophageal adenocarcinoma (EAC) is the sixth-leading cause of cancer-related death. Although pyrimidine analogue-based neoadjuvant and adjuvant therapies are widely used, patient responses remain variable. Emerging evidence indicates that bacteria-derived metabolites influence tumor biology and therapy outcomes. To identify non-canonical plasma metabolites linked to cancer biology, we performed correlation analyses between untargeted metabolomics profiles and overall survival. This approach revealed a bacterial metabolite called L-pentahomoserine, or L-2-amino-5-hydroxypentanoic acid (L-2A5HPA), to be positively associated with overall survival. Notably, L-2A5HPA promoted cell survival under nutrient limitation by redirecting glucose metabolism towards aspartate and pyrimidine biosynthesis. In vitro, L-2A5HPA uptake varied among cell lines and was controlled by stereospecific transporters. Furthermore, metabolic profiling in mouse models of liver cancer showed different levels of L-2A5HPA and a strong correlation with pyrimidine intermediates, dihydroorotate and orotate. The link between L-2A5HPA, pyrimidine nucleotide metabolism, and cell survival provides mechanistic insight into its association with patient outcome. Our findings position L-2A5HPA as a metabolite with potential to become a prognostic biomarker for EAC and underscores its role in metabolic adaptation under nutrient-deprived conditions.

cancer biology↗

bioRxiv2025

Paternal over- and under-nutrition program fetal and placental development in a sex-specific manner in mice

The association between sub-optimal paternal diet and offspring well-being is becoming established. However, the underlying mechanisms are yet to be fully defined. The aim of this study was to establish the impact of over- and under-nutrition, with or without macronutrient supplementation, on male reproductive fitness and post-fertilisation development. Male C57/BL6J mice were fed either control diet (CD), isocaloric low protein diet (LPD), high fat/sugar Western diet (WD) or LPD or WD supplemented with methyl-donors and carriers (MD-LPD or MD-WD respectively) for 8 weeks before mating with virgin C57/BL6J females. Placental tissue was collected at embryonic day (E)8.5, to assess early placental (ectoplacental cone) morphology and metabolism and E17.5 for sex-specific transcriptomic profiling. Post-mating, stud male tissues were harvested for assessment of testicular morphology and gene expression, gut microbiota composition and metabolic status. WD and MD-WD males displayed increased adiposity, hepatic cholesterol and free fatty acids and gut microbiota dysbiosis when compared to CD fed males. In the testes, WD and MD-WD perturbed the expression of genes associated with metabolism and transcription regulation. Additionally, we observed differential expression of multiple genes within the Wnt signalling pathway, central in the regulation of cellular proliferation, migration, survival, and cell fate determination during development. Despite no impact on fundamental male fertility, significant changes in ectoplacental cone metabolism, fetal growth, and placental gene expression were observed in response to specific dietary regimens. Interestingly, while CD male and female placentas displayed 301 genome-wide, sexually-dimorphic genes, LPD, MD-LPD, WD and MD-WD male and female placentas possessed only 13, 0, 14 and 15 sexually-dimorphic genes respectively. Our data show that while sub-optimal paternal diet has minimal impact on male fertility, fetal and placental development are perturbed in a sex-specific manner.

developmental biology↗

bioRxiv2023

The eIF4A2 negative regulator of mRNA translation promotes extracellular matrix deposition to accelerate hepatocellular carcinoma initiation

Increased protein synthesis supports growth of established tumours. However, how mRNA translation contributes to early tumorigenesis remains unclear. Here we show that following oncogene activation, hepatocytes enter a non-proliferative/senescent-like phase characterized by 5{beta}1 integrin-dependent deposition of fibronectin-rich extracellular matrix (ECM) niches. These niches then promote exit from oncogene-induced senescence to permit progression to proliferating hepatocellular carcinoma (HCC). Removal of eIF4A2, a negative regulator of mRNA translation, boosts the synthesis of membrane/secretory proteins which drives a compensatory increase in the turnover/degradation of membrane proteins including 5{beta}1 integrin. This increased membrane protein degradation, in turn, compromises generation of ECM-rich tumour initiation niches, senescence-exit and progression to proliferating HCC. Consistently, pharmacological inhibition of mRNA translation following eIF4A2 loss restores ECM deposition and reinstates HCC progression. Thus, although inhibition of protein synthesis may be an effective way to reduce tumour biomass and the growth of established tumours, our results highlight how agents which reduce mRNA translation, if administered during early tumorigenesis, may awaken senescent cells and promote tumour progression.

cancer biology↗

bioRxiv2023

Multimodal decoding of human liver regeneration

The liver has a unique ability to regenerate1,2, however in the setting of acute liver failure (ALF) this regenerative capacity is often overwhelmed and emergency liver transplantation is the only curative option3-5. To advance our understanding of human liver regeneration and to inform design of pro-regenerative therapies, we use paired single-nuclei RNA sequencing (snRNA-seq) combined with spatial profiling of healthy and ALF explant human livers to generate the first single-cell, pan-lineage atlas of human liver regeneration. We uncover a novel ANXA2+ migratory hepatocyte subpopulation which emerges during human liver regeneration, and a corollary migratory hepatocyte subpopulation in a mouse model of acetaminophen (APAP)-induced liver regeneration. Importantly, interrogation of necrotic wound closure and hepatocyte proliferation across multiple timepoints following APAP-induced liver injury in mice demonstrates that wound closure precedes hepatocyte proliferation. 4-D intravital imaging of APAP-induced mouse liver injury identifies motile hepatocytes at the edge of the necrotic area, enabling collective migration of the hepatocyte sheet to effect wound closure. Depletion of hepatocyte ANXA2 expression reduces HGF-induced human and mouse hepatocyte migration in vitro, and abrogates necrotic wound closure following APAP-induced mouse liver injury. Taken together, our work dissects unanticipated aspects of liver regeneration, demonstrating an uncoupling of wound closure and hepatocyte proliferation and uncovering a novel migratory hepatocyte subpopulation which mediates wound closure following liver injury. Therapies designed to promote rapid reconstitution of normal hepatic microarchitecture and reparation of the gut-liver barrier may open up new areas of therapeutic discovery in regenerative medicine.

cell biology↗

bioRxiv2021

Genetic manipulation using hepatocyte-targeting adeno-associated viral vectors has minimal off-target effects.

Mice are a widely used pre-clinical model system in large part due to their potential for genetic manipulation. The ability to manipulate gene expression in specific cells under temporal control is a powerful experimental tool. The liver is central to metabolic homeostasis and a site of many diseases, making the targeting of hepatocytes attractive. Adeno-Associated Virus 8 (AAV8) vectors are valuable instruments for the manipulation of hepatocellular gene expression. However, their off-target effects in mice have not been thoroughly explored. Here, we sought to identify the short-term off-target effects of AAV8 administration in mice. To do this, we injected C57BL/6J Wild-Type mice with either recombinant AAV8 vectors expressing Cre recombinase or empty AAV8 vectors and characterised the changes in general health and in liver physiology, histology and transcriptomics compared to uninjected controls over 1 week. We observed an acute and transient reduction in homeostatic liver proliferation together with induction of the DNA damage marker {gamma}H2AX following AAV8 administration. The latter was enhanced upon Cre recombinase expression by the vector. Furthermore, we observed transcriptional changes in genes involved in circadian rhythm and response to infection. Notably, there were no additional transcriptomic changes upon expression of Cre recombinase by the AAV8 vector. Overall, there was no evidence of liver injury, dysfunction or leukocyte infiltration following AAV8 infection. These data support the use of AAV8-based Cre recombinase delivery as a specific tool for hepatocellular gene manipulation with minimal effects on murine physiology but highlight the off target effects of these systems. Summary statementThis paper provides a comprehensive characterisation of the short-term effects of administration of Adeno-Associated Virus 8 on murine physiology, liver histology and liver transcriptome.

cell biology↗

bioRxiv2020

Absent expansion of pericentral hepatocytes and altered physiology in Axin2CreERT2 mice

Abstract/IntroductionUnderstanding how the liver regenerates is a key biological question. Hepatocytes are the principle regenerative population in the liver. Recently, numerous lineage tracing studies (which apply genetic tagging to a restricted population and track its descendants over time) have reported conflicting results using a variety of hepatocyte based reporting systems in mice1,2. The first significant lineage tracing from a distinct subpopulation of hepatocytes in homeostasis reported hyper-proliferation of self-renewing pericentral hepatocytes with their subsequent expansion across the liver lobule3. This study used a CreERT2 construct knocked into the endogenous Axin2 locus; here termed Axin2CreERT2. Subsequent studies, using either a different pericentral marker (Lgr54) or a different AxinCreERT2 transgene5, did not show lineage tracing. Here we aim to reconcile these discrepancies by re-evaluating lineage tracing in the Axin2CreERT2 knock-in model and explore the physiological consequences of this mutant allele. We were unable to find evidence of expansion of an Axin2CreERT2 labelled population and show that this population, whilst zonated, is spread throughout the lobule rather than being zonally restricted. Finally, we report that this allele results in profound perturbation of the Wnt pathway and physiology in the mouse.

cell biology↗

bioRxiv2020

Distinct neural substrates of individual differences in components of reading comprehension in adults with or without dyslexia

Reading comprehension is a complex task that depends on multiple cognitive and linguistic processes. According to the updated Simple View of Reading framework, in adults, individual variation in reading comprehension can be largely explained by combined variance in three component abilities: (1) decoding accuracy, (2) fluency, and (3) language comprehension. Here we asked whether the neural correlates of the three components are different in adults with dyslexia as compared to typically-reading adults and whether the relative contribution of these correlates to reading comprehension is similar in the two groups. We employed a novel naturalistic fMRI reading task to identify the neural correlates of individual differences in the three components using whole-brain and literature-driven regions-of-interest approaches. Across all participants, as predicted by the simple view framework, we found distinct patterns of associations with linguistic and domain-general regions for the three components, and that the left-hemispheric neural correlates of language comprehension in the angular and posterior temporal gyri made the largest contributions to explaining out-of-scanner reading comprehension performance. These patterns differed between the two groups. In typical adult readers, better fluency was associated with greater activation of left occipitotemporal regions, better comprehension with lesser activation in prefrontal and posterior parietal regions, and there were no significant associations with decoding. In adults with dyslexia, better fluency was associated with greater activation of bilateral inferior parietal regions, better comprehension was associated with greater activation in some prefrontal clusters and lower in others, and better decoding skills were associated with lesser activation of bilateral prefrontal and posterior parietal regions. Extending the behavioral findings of skill-level differences in the relative contribution of the three components to reading comprehension, the relative contributions of the neural correlates to reading comprehension differed based on dyslexia status. These findings reveal some of the neural correlates of individual differences in the three components and the underlying mechanisms of reading comprehension deficits in adults with dyslexia.

neuroscience↗

bioRxiv2019

speck, first identified in Drosophila melanogaster in 1910, is encoded by the Arylalkalamine N-acetyltransferase (AANAT1) gene

The pigmentation mutation speck is a commonly used recombination marker characterized by a darkly pigmented region at the wing hinge. Identified in 1910 by Thomas Hunt Morgan, speck was characterized by Sturtevant as the most \"workable\" mutant in the rightmost region of the second chromosome and eventually localized to 2-107.0 and 60C1-2. Though the first speck mutation was isolated over 115 years ago, speck is still not associated with any gene. Here, as part of an undergraduate-led research effort, we show that speck is encoded by the Arylalkylamine N-acetyltransferase 1 (AANAT1) gene. Both alleles from the Morgan lab contain a retrotransposon in exon 1 of the RB transcript of the AANAT1 gene. We have also identified a new insertion allele and generated multiple deletion alleles in AANAT1 that all give a strong speck phenotype. In addition, expression of AANAT1 RNAi constructs either ubiquitously or in the dorsal portion of the developing wing generates a similar speck phenotype. We find that speck alleles have additional phenotypes, including ectopic pigmentation in the posterior pupal case, leg joints, cuticular sutures and overall body color. We propose that the acetylated dopamine generated by AANAT1 decreases the dopamine pool available for melanin production. When AANAT1 function is decreased, the excess dopamine enters the melanin pathway to generate the speck phenotype.

developmental biology↗

bioRxiv2019

Acquired loss of cardiac vagal activity is associated with myocardial injury in patients undergoing non-cardiac surgery: prospective observational mechanistic cohort study.

BackgroundMyocardial injury is more frequent after non-cardiac surgery in patients with preoperative cardiac vagal dysfunction as quantified by delayed heart rate recovery after cessation of cardiopulmonary exercise testing. Here, we hypothesised that serial and dynamic measures of perioperative cardiac vagal activity should also be associated with myocardial injury after non-cardiac surgery.\n\nMethodsSerial measures in cardiac vagal activity were quantified preoperatively and daily using heart rate variability and a standardised orthostatic challenge in patients undergoing elective non-cardiac surgery. The primary outcome was myocardial injury (high-sensitivity troponin (hsTnT) [≥]15ng.L-1) within 48h of surgery. Clinicians, patients and investigators were blinded to hsTnT. The exposure of interest was cardiac vagal activity (high-frequency power spectral analysis [HFlog]) and heart rate recovery after a standardised orthostatic challenge.\n\nResultshsTnT[≥]15ng.L-1 occurred in 48/189 [25%] patients, of whom 41/48 [85%] had a revised cardiac risk index score <2. Patients with a post surgery troponin HsTnT [≥]15ng.L-1 were associated with an early loss (within 24h) of cardiac vagal activity (HFLog) post surgery compared to day of surgery (4.19 [95%CI:3.62-4.75] vs 5.22 [95%CI:4.64-5.81]; p<0.001). Heart rate recovery after a standardised orthostatic challenge after surgery was slower in patients with hsTnT[≥]15ng.L-1 (5 beats minute-1 (95% CI: 3 -7), compared to heart rate recovery in patients who remained free of myocardial injury (10 beats minute-1 (95%CI:7 to 12]; p = 0.02).\n\nConclusionsReal-time, serial heart rate measures indicating loss of cardiac vagal activity are associated with perioperative myocardial injury in lower-risk patients undergoing non-cardiac surgery.

physiology↗