Biology subjects

Dutta, P.

Publications and source records attributed to Dutta, P..

At least 19 recordsLinked to original sources

bioRxiv2026

Characterization of Vlf1 as a regulator of lipophagy.

Lipid droplets (LDs) are unique organelles, surrounded by a phospholipid monolayer. They are present in most eukaryotic cells including the unicellular model organism S. cerevisiae. LDs store neutral lipids which serve as precursors for amphipathic membrane lipids and as an energy reserve. Loss of LDs in S. cerevisiae results in multiple cellular defects impairing lipid homeostasis and the biogenesis and function of other organelles. Here, we find that the expression levels of many proteins in isolated mitochondrial fractions are altered in cells that cannot synthesize neutral lipids and therefore lack LDs. In addition, among several downregulated proteins, we identified the previously uncharacterized Ylr001c (which we name Vlf1 for Vacuolar Lipophagy Factor 1). We show that Vlf1 is glycosylated and, in contrast to some previous reports, is actually localized to the vacuole. Furthermore, we demonstrate that changes in Vlf1 expression alter growth sensitivity to rapamycin, and detected a physical interaction of Vlf1 with Atg15, a lipase involved in autophagy. Additionally, we observe higher levels of autophagy/lipophagy in the absence of Vlf1 and a reduction upon overexpression of the protein. Taken together, the effects on lipohagy by Vlf1 makes it, according to our knowledge, the first vacuolar lipophagy regulator identified in S. cerevisiae.

cell biology↗

bioRxiv2026

Vibrio cholerae VgrG1-ACD Targets E. coli MreB and Regulates Cellular Morphology

Vibrio cholerae employs the Type VI Secretion System (T6SS) to outcompete neighboring bacteria and establish successful colonization within the polymicrobial gut. The T6SS effector VgrG1 contains a C-terminal Actin Crosslinking Domain (VgrG1-ACD), well known for irreversibly crosslinking eukaryotic actin to disrupt the host cytoskeleton. However, whether VgrG1-ACD also contributes directly to interbacterial competition has remained unexplored. Here, we identify a previously unrecognized bacterial target of VgrG1-ACD: MreB, the bacterial actin homolog essential for cell shape, cell wall synthesis, and cytoskeletal organization. We demonstrate that VgrG1-ACD specifically binds Escherichia coli MreB, resulting in pronounced morphological defects and impaired bacterial growth. Notably, unlike its activity toward mammalian actin, VgrG1-ACD targets MreB without crosslinking it, revealing a distinct mode of action. These findings expand the functional repertoire of VgrG1-ACD beyond host-directed virulence and uncover a dual-targeting strategy through which a single T6SS effector manipulates both mammalian actin and its bacterial homolog, likely enhancing V. cholerae fitness during interbacterial competition and host colonization.

microbiology↗

bioRxiv2026

PGViS: Personal Genome Variant interpretation Score for lung cancer genomes

Inherited lung cancer risk arises from both protein-coding and non-coding germline variants, but the functional non-coding component is largely uncharacterized. Genome-wide association studies and polygenic risk scores identify tag variants, not causal ones. Neither resolves which regulatory element is perturbed. DNA foundation models such as DNABERT decode non-coding variant effects directly from sequence, without a large GWAS cohort. What is missing is a patient-level framework linking these predictions to population-level variant prevalence. We present PGViS (Personal Genome Variant interpretation Score), a statistical framework that quantifies individual non-coding germline regulatory risk in non-small cell lung cancer (NSCLC). PGViS integrates three variant-level signals: DNABERT-predicted disruption at transcription factor binding and splice sites, the cancer v/s reference alternate allele frequency shift, and a regulatory interaction term derived from cancer-to-reference allele frequency ratios. Each signal is weighted by cohort prevalence which are aggregated into a single ancestry-matched, reference-normalized score per patient. We applied PGViS to germline whole-genome sequencing from 1,102 TCGA and CPTAC patients, using the 1000 Genomes Project (n = 2,504 individuals) as the normal population reference. PGViS separated adenocarcinoma (AD) and squamous cell carcinoma from controls in European ancestry and East Asian AD. Genes at contributing loci were enriched for PI3K-Akt, Wnt, DNA damage response, and epithelial-mesenchymal transition programs. Smoking-stratified analysis concentrated this signal on canonical NSCLC driver pathways. PGViS is modular: it accommodates cohorts with broader ancestral representation and can adapt to other solid tumors, offering a cost-effective route to personal-genome risk assessment from germline variants alone.

bioinformatics↗

bioRxiv2026

Myeloid STING restrains cardiac remodeling by suppressing macrophage amyloid precursor protein

Mitochondrial DNA (mtDNA) released into the cytosol activates innate immune signaling and promotes inflammation, yet its role in macrophages following sterile tissue injury remains poorly understood. Here, we show that cardiac macrophages from both patients and mice with myocardial infarction (MI) exhibit increased mitochondrial biogenesis, mitochondrial content, membrane potential, and expression of mitochondrial nucleases that facilitate mtDNA release. Consistently, macrophage-specific silencing of genes regulating mitochondrial biogenesis or mtDNA processing attenuated adverse cardiac remodeling after MI. Unexpectedly, despite the role of mtDNA in activating the cGAS-STING pathway, myeloid deletion or macrophage-specific silencing of Sting or cGas exacerbated ventricular dilation, fibrosis, and contractile dysfunction following MI. Single-cell transcriptomic and cell communication analyses identified amyloid precursor protein (APP) as a key downstream effector of STING in cardiac macrophages. Macrophage-specific in vivo App silencing rescued the detrimental effects of myeloid Sting deficiency, establishing APP as a critical mediator of adverse remodeling. Mechanistically, STING interacted with the transcriptional repressor MZF1, promoted its nuclear localization, facilitated its binding to the App promoter, and suppressed App transcription to restrain adverse cardiac remodeling. Together, our findings uncover an unexpected cardioprotective function of myeloid STING and identify the STING-MZF1-APP axis as a previously unrecognized mechanism governing cardiac repair after myocardial infarction.

cell biology↗

bioRxiv2026

Humanin analogue promotes metabolic reprogramming to protect the ischemic heart

BackgroundMyocardial ischemia drives adverse cardiac remodeling, metabolic inflexibility, and progression to heart failure. Mitochondrial dysfunction and impaired substrate utilization contribute to cardiomyocyte death and fibrosis, particularly with aging. Humanin (HNG), a mitochondria-derived peptide, has been shown to reduce acute ischemic injury, but its role in chronic ischemia and cardiac remodeling remains unknown. MethodsWe investigated the effects of HNG treatment in young and aged murine models of myocardial ischemia without reperfusion. Cardiac function and structure were assessed by echocardiography and molecular markers of remodeling. Myocardial metabolism was interrogated using targeted metabolomics, gene expression, substrate uptake assays, and metabolic flux analyses. Mechanistic studies examined glucose transporter trafficking and protein-protein interactions. ResultsHNG treatment improved cardiac function and significantly attenuated adverse remodeling in both young and old mice. HNG treatment induced marked metabolic reprogramming characterized by reduced myocardial fatty acid content, downregulation of fatty acid uptake and oxidation pathways, and decreased oxidative stress. Importantly, these changes were accompanied by enhanced glucose oxidation, increased tricarboxylic acid cycle flux, improved coupling of glycolysis to mitochondrial oxidation, and increased ATP production. Time-course studies demonstrated that increased glucose oxidation preceded reductions in fatty acid oxidation, indicating a primary role for glucose metabolism in HNG-mediated cardioprotection. Mechanistically, we identified vesicle-associated membrane protein 7 (VAMP7) as a novel binding partner of HNG, and that this interaction is required for GLUT4 translocation to the plasma membrane and HNG-induced ATP generation. ConclusionsHNG protects the ischemic heart by promoting metabolic reprogramming that shifts substrate utilization from fatty acids to glucose and limiting maladaptive remodeling. These findings identify HNG as a novel regulator of cardiac metabolism and a potential therapeutic strategy for ischemic heart failure. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=65 SRC="FIGDIR/small/732776v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1929de8org.highwire.dtl.DTLVardef@bcf254org.highwire.dtl.DTLVardef@c99b70org.highwire.dtl.DTLVardef@1fc08bb_HPS_FORMAT_FIGEXP M_FIG C_FIG What are the clinical implications?Heart failure (HF) is a major global health concern, affecting over 6.7 million adults in the United States alone, with projections to exceed 11 million by 2050. Myocardial infarction (MI) is a leading cause of HF. Despite substantial advances in acute MI care, survivors remain at high risk for adverse cardiac remodeling and chronic HF, especially in the elderly. We report here that treatment with a potent analog of Humanin (HN), an endogenous mitochondria-associated peptide, decreases infarct size, decreases fibrosis and improves cardiac function following cardiac ischemia induced by permanent ligation of coronary artery in both young and aged mice. These effects are associated with changes in cardiac metabolism, oxidative stress, and remodeling. HN and analogs have been shown to be beneficial in many age-related diseases. The endogenous origin of Humanin, its favorable safety profile in preclinical studies and its pleiotropic effects support targeting HNG as a promising therapeutic strategy for ischemic heart disease and post-myocardial infarction heart failure in humans.

Systems Biology↗

bioRxiv2026

Alveolar Epithelial Cell Loss of the Mitochondrial Regulator TFAM Drives Progressive Lung Fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterized by failed alveolar epithelial repair and progressive fibrotic remodeling. Although aberrant reprogramming of alveolar type 2 (AT2) cells and accumulation of transitional AT2 states are increasing recognized as central features of IPF, the epithelial-intrinsic mechanisms that initiate these pathogenic states remain incompletely understood. Here, we identify mitochondrial transcription factor A (TFAM), a regulator of mitochondrial DNA maintenance, as a critical regulator of AT2 cell homeostasis. TFAM expression was reduced in AT2 cells from human IPF lungs. Inducible AT2 cell-specific Tfam deletion in mice caused spontaneous fibrotic remodeling and increased susceptibility to bleomycin-induced lung injury. TFAM-deficient AT2 cells acquired KRT8+ transitional and p21+ senescence-associated features before the onset of fibrotic transformation, accompanied by impaired oxidative phosphorylation, redox imbalance, mitochondrial superoxide accumulation, repression of mtDNA-encoded respiratory genes, and disrupted mitochondrial ultrastructure. TFAM-deficient AT2 cells developed a profibrotic secretory program that promoted extracellular matrix deposition and fibroblast activation. We further identified insulin-like growth factor-binding protein 2 (IGFBP2) as a secreted mediator induced in TFAM-deficient AT2 cells. IGFBP2 was elevated in AT2 cells in human IPF lung tissue and bronchoalveolar lavage fluid (BALF) from patients with IPF. IGFBP2 was detected in supernatants from fibrotic human precision-cut lung slices (hPCLS). IGFBP2 neutralization attenuated profibrotic remodeling in fibrotic hPCLS. Collectively, our findings identify TFAM-dependent mitochondrial homeostasis as an epithelial checkpoint linking AT2 cell-state stability to impaired epithelial-mesenchymal crosstalk driving pulmonary fibrosis.

pathology↗

bioRxiv2026

Gut-derived metabolic reprogramming drives immune aging and tissue degeneration

Aging is characterized by changes in gut microbiome, metabolic imbalance and chronic inflammation, yet how these processes integrate to drive tissue degeneration remains poorly defined. Using age-related macular degeneration (AMD) as a model of tissue aging, we identify a diet-induced metabolic-immune axis that promotes systemic and retinal degeneration. In mice, a high-fat, cholesterol-enriched (HFC) diet induced perturbations in the gut structural integrity and microbiome repertoire, as well as systemic metabolic aging signatures, prominently marked by reduced circulating histidine. Plasma histidine levels were similarly decreased in AMD patients and inversely correlated with body mass index (BMI) in control donors. These diet-induced gut microbiome changes and subsequent metabolic alterations promoted peripheral innate immune reprogramming, with expansion of inflammatory neutrophils and monocytes that infiltrated the outer retina in a mouse model. Mechanistically, the gut-derived IGF1R/AKT2 signaling acts as a central regulator of global epigenetic remodeling and systemic immune aging under high-fat conditions in C. elegans. In a mouse model with an age-dependent dry AMD-like pathology, distinct retinal pigment epithelium (RPE) subpopulations exhibited downregulation of the histidine transporter SLC7A5, linking metabolic stress to activation of MIF/CD74-dependent inflammatory signaling between RPE and infiltrating immune cells. Histidine supplementation or AKT2 phospho-state modulation attenuated systemic immune activation and rescued retinal degeneration. These findings identify histidine-axis dysregulation as a mechanistic bridge between diet-induced microbiome changes, metabolic stress, immune aging, and retinal degeneration.

cell biology↗

bioRxiv2026

A Prefusion Form of Herpes Simplex Virus 1 gB has a Distinct Antigenic Signature

Herpes simplex virus (HSV) fusion and entry is mediated by a cascade of interactions among gB, gD and gH/gL. The gB homotrimer undergoes a conformational transition from a metastable prefusion state to a more stable postfusion form, driving fusion of the viral envelope and a host cell membrane. An H516P mutation in gB domain III restricts formation of the extended core alpha helix and constrains gB in a prefusion state. Several prefusion gB structures have been determined that contain this mutation. We assessed the antigenic reactivity of gB H516P by quantitative immunodotblot using a panel of gB-reactive monoclonal antibodies All antibodies tested bound to both prefusion (H516P) gB and wild type gB. Antibodies tested to gB domains II, IV and V exhibited differential binding to H516P gB compared to wild type gB. The results suggest that gB H516P has a distinct antigenic profile. The antigenic signature of H516P may be useful as a rapid indicator of prefusion forms of gB. The low pH environment of the cellular endosome is a cell-specific factor for HSV entry and triggers antigenic changes in gB. The step at which low pH impacts gB refolding to execute fusion is not well-understood. The results suggest that gB H516P undergoes wild-type-like conformational changes in gB domains I and V triggered by low pH. We propose that pH acts on an early stage of gB fusion function, prior to extension of the domain III core helix.

microbiology↗

bioRxiv2026

A stereotyped glial attachment determines the morphology and function of neuronal cilia

Primary cilia are signaling hubs that influence nearly every aspect of cell physiology. Neuronal primary cilia were recently discovered to interact with glia in the mammalian brain, but how cilia-glia attachments form and what roles they play remain unknown. Here, we find that two C. elegans sensory neurons (URX and BAG) use their primary cilia to attach to a specific glial partner (ILsoL). Through a genetic screen, we find that cilia-glia attachment requires BUG-1, a secreted protein with conserved cell adhesion domains that localizes to the cilia-glia attachment site. In the absence of BUG-1, neuronal cilia are present but fail to attach to the glial cell. We find that loss of cilia-glia attachment alters cilia morphology and disrupts stimulus-evoked calcium dynamics in cilia. We propose that primary cilia not only act as antennae for long-range cell communication, but also form close-range cell attachments that modulate cell signaling.

developmental biology↗

bioRxiv2026

HViLM: A Foundation Model for Viral Genomics Enables Multi-Task Prediction of Pathogenicity, Transmissibility, and Host Tropism

MotivationThe emergence of novel viral pathogens poses critical threats to global health, yet current computational approaches for viral risk assessment are predominantly virus-specific and require extensive retraining for each new threat. Computational methods for rapid characterization of emerging viruses across multiple epidemiologically relevant dimensions--pathogenicity, host tropism, and transmissibility--are urgently needed to inform public health responses and guide experimental prioritization. ResultsWe present HViLM (Human Virome Language Model), the first foundation model for panviral genomic analysis through continued pre-training of DNABERT-2 on 5 million non-redundant viral sequences (MMseqs2-clustered from 25 million chunks at 80% identity) spanning 9,000 species across 45+ viral families from the VIRION database. We introduce the Human Virome Understanding Evaluation (HVUE) benchmark comprising seven curated datasets across three prediction tasks: pathogenicity classification, host tropism prediction, and transmissibility assessment. Through parameter-efficient fine-tuning with LoRA, HViLM achieves state-of-the-art performance with average accuracies of 95.32% for pathogenicity, 96.25% for host tropism, and 97.36% for transmissibility assessment. The model demonstrates robust cross-family generalization, substantially outperforming sequence-similarity baselines and general genomic foundation models. Attention-based interpretability analysis reveals that HViLM captures biologically meaningful pathogenicity determinants through molecular mimicry of host regulatory elements, including convergent evolution of eight independent sequences targeting Interferon Regulatory Factor 1 (Irf1) for immune evasion. AvailabilityThe HVUE benchmark datasets, training scripts, and complete implementation are publicly available at https://github.com/duttaprat/HViLM. Pre-trained HViLM-base model weights and fine-tuned task-specific variants are available on Hugging Face at https://huggingface.co/duttaprat/HViLM-base. Supplementary informationSupplementary data are available online.

bioinformatics↗

bioRxiv2026

Gum Odina, a novel prebiotic, promotes the expression of sealing tight junction proteins in colon organoids developed from the C57BL/6 mice model

Maintaining gut-microbiome homeostasis is the biggest issue worldwide as per public health concerns. Gut probiotics not only inhibit pathogen invasion in the systemic circulation but also help us metabolize complex food. Therefore, for decades, gut dysbiosis has been proven to be the gateway to several diseases, leading to comorbidity and even mortality. Prebiotics are natural products, mainly nondigestible food ingredients, that help the selective growth of probiotic bacteria in the gut. This study focuses on the novel Gum-Odina (GO) prebiotic and its efficacy on gut microbial metabolite modulation and maintaining gut barrier integrity. Gut wall enterocytes are integrated by a series of tight junctional (TJ) proteins. This study explains the effect of GO prebiotic-modulated gut metabolites on tight-junctional (TJ) protein expression in a murine colon Organoid model. Fecal microbiota from a colitis patient were used to inoculate the SHIME gut simulator, comprising a colitis control run and a Gum-Odina-supplemented run to enrich commensal bacteria selectively. Metabolites from both groups were then applied to healthy colon organoids. According to the mRNA expression analysis, tight junctional sealing proteins such as Zonula occludens, or ZO-1, Occludin, Claudin-1, 4, and 5 were significantly upregulated in the colon organoids upon Gum-Odina administration, whereas no change in the Junctional Adhesion Molecule-A or JAM-A was observed. Downregulation of sealing TJ proteins is the Hallmark of Leaky gut, which was successfully reversed using the Gum-Odina supplement. Hence, Gum-Odina prebiotics have a promising capability to reduce colitis-induced gut permeability and can be considered to be a therapeutic agent in the future.

cell biology↗

bioRxiv2025

TSProm: Deciphering the Genomic Context of Tissue Specificity

Characterizing tissue-specific (TSp) gene expression is crucial for understanding development and disease; however, traditional expression-based methods often overlook the latent "regulatory grammar" embedded in the non-coding DNA, particularly in distal promoter regions. Here, we introduce TSProm, a framework that specializes a DNA foundation model (DNABERT2) to decipher the long-range regulatory logic of TSp promoters at the gene isoform level. The contributions of our work are two-fold. First, we propose a novel comparative design that trains two distinct models, A: for general promoter biology and B: for TSp regulation. These models enable the precise isolation of sequence motifs around the transcription start site that uniquely define tissue identity. Second, we introduce a comprehensive explainable AI (xAI) module that integrates attention-based discovery with model-agnostic SHAP analysis to provide robust, cross-validated interpretations of learned features. Applying this framework to human brain, liver, and testis promoters, we identified and validated clinically relevant transcription factors (TFs) in the brain, including SP1, MYC, and HES6, and confirmed their known roles in diseases such as gliomas and neuroblastomas. Our analysis further revealed that C2H2 Zinc Finger proteins are a dominant feature of the global landscape of TSp gene regulation. TSProm provides a novel and interpretable framework for identifying TSp gene regulatory elements, offering powerful computational tools for the study of tissue-specific gene regulation in normal and disease conditions.

bioinformatics↗

bioRxiv2025

Unraveling the Mechanistic Links Between Blood Pressure Regulation and Calcium-Magnesium Homeostasis: Insights into Hypertension, Hyperparathyroidism, and Mineral Disorders

The systems regulating blood pressure and calcium-magnesium (Ca2+-Mg2+) homeostasis are increasingly recognized to have significant, clinically relevant interactions, where alterations in one can lead to significant changes in the other. In this study, we developed a computational model integrating blood pressure regulation and Ca2{square}-Mg2{square} homeostasis in a male rat. We simulated various conditions, including hypertension, Ca2{square}, Mg2{square}, and vitamin D3 deficiencies, and primary hyperparathyroidism. Simulations of hypertension, induced by various stimuli like increased renin or aldosterone secretion, demonstrated significant effects on parathyroid hormone (PTH), calcitriol, renal Ca2{square}/Mg2{square} handling, and bone resorption. Dietary Ca2{square}, Mg2{square}, and vitamin D3 deficiencies elevated mean arterial pressure, with Mg2{square} deficiency having a stronger effect. Furthermore, the model predicted that primary hyperparathyroidism elevates PTH, Ca2{square}, and calcitriol, leading to increased mean arterial pressure and bone loss. Overall, this model provides valuable insights into the mechanistic links between blood pressure regulation and Ca2{square}-Mg2{square} homeostasis, offering insights into clinical conditions like hypertension and hyperparathyroidism.

systems biology↗

bioRxiv2025

Mathematical Modeling of Bone Remodeling after Surgical Menopause

Osteoporosis is a skeletal pathology characterized by decreased bone mass and structural deterioration resulting from an imbalance in bone metabolic processes. Estrogen deficiency in postmenopausal women leads to an increased risk of osteoporosis, while women who have undergone complete oophorectomies display an even higher risk due to the sudden decrease in estrogen. Some evidence indicates that bone loss slows in the period beyond 15 years after surgery; however, there is substantial uncertainty in clinical data. To explore the effects of surgically induced menopausal transition, here we propose a mathematical model for the bone cell dynamical responses to sudden estrogen deficiency, which extends an existing model for osteoporosis due to aging and natural menopause. Using data on the key impacts observed in female mice and humans after bilateral oophorectomy, this new model considers the role of osteocytes embedded within the bone mineralized matrix in regulating osteoclastogenesis, which results in increased bone resorption after surgical menopause. The values of model parameters in natural and surgical menopause were estimated from aggregated human clinical data from existing longitudinal studies. The new model effectively captures the previously unmodeled increase in bone loss during the first 15 years post-surgical menopause and the rebound in bone mineral density in the long-term. With this model, effects of treatments on targeting osteocyte dynamics could be explored in the future.

systems biology↗

bioRxiv2025

Activated fatty acid synthesis pathway in macrophages propagates pathogenic fibroblast expansion after myocardial infarction

Metabolic pathways, such as fatty acid oxidation and oxidative phosphorylation, can modulate inflammatory cells. However, little is known about the effects of the fatty acid synthesis pathway in macrophages on inflammation and cardiac remodeling after myocardial infarction (MI). Using spatial metabolomics, here we show that cardiac macrophages residing in the infarct synthesize de novo fatty acids and increase the production of fatty acid enzymes including ACLY and FASN. Mice deficient in myeloid Acly and Fasn have improved cardiac function after MI and reduced fibrosis. Combining Cleavage Under Targets and Release Using Nuclease (CUT&RUN), RNA sequencing analysis of Acly-/-macrophages, and macrophage-specific in vivo gene silencing, we demonstrate that ACLY acetylates the promoter region of the upstream regulator Krt17, which drives the production of pro-fibrotic cytokines, including IL-33. Single-cell RNA sequencing of cardiac fibroblasts shows that the expansion of a population of fibroblasts (Fibroblast 5) expressing high levels of extracellular matrix genes after MI is confined in the absence of macrophage Acly. Finally, the analysis of spatial multi-omics data of human hearts with MI uncovers myofibroblasts with the Fibroblast 5 gene signature. These myofibroblasts are located near cardiac macrophages expressing high levels of ACLY. In summary, we show that macrophage ACLY and FASN are deleterious in MI pathogenesis.

immunology↗

bioRxiv2025

Macrophage efferocytosis is controlled by epigenetic modifications mediated by RBPJ

Efferocytosis, phagocytic clearance of apoptotic cells, is crucial for inflammation resolution and maintenance of tissue homeostasis. However, it is not known how epigenetic alterations govern macrophage-mediated efferocytosis. A Cleavage Under Targets and Release Using Nuclease (CUT&RUN) sequencing revealed a genome-wide selective suppression of H3K9me3, a heterochromatin mark that represses gene activity, in macrophages undergoing efferocytosis. Moreover, Recombination Signal Binding Protein for Immunoglobulin Kappa J region (RBPJ), which is a transcription factor typically involved in the canonical Notch signaling process, dampened this epigenetic modification, enhanced apoptotic cell clearance, and suppressed inflammation by mouse atherosclerotic plaque, alveolar, peritoneal, and bone marrow-derived macrophages and human primary macrophages. Inhibition of the Notch signaling in macrophages significantly reduced efferocytosis whereas activation of this signaling augmented apoptotic debris clearance. Mechanistically, RBPJ upregulated Stard13 and Arsg by diminishing H3K9me3 on their promoters. Stard13 promoted efferocytosis by magnifying actin polymerization via inhibition and activation of Rho and RAC GTPases, respectively. Genetic and pharmacological inhibitions of SUV39H1/H2, the methyltransferases that are responsible for H3K9 trimethylation, amplified the expression of Stard13 and Arsg, and augmented efferocytosis by RBPJ-/- macrophages. In sum, this study shows epigenetic regulation of efferocytosis in tissue macrophages.

immunology↗

bioRxiv2025

Disruption of the Wnt-antagonist Apc in the pituitary stem cells drives the development of adamantinomatous craniopharyngioma.

Adamantinomatous craniopharyngiomas (aCPs) are complex intracranial neoplasms that generally arise in the sellar and suprasellar region of the brain which affect the endocrine and nervous systems causing severe sequelae. Activating mutations resulting in degradation-resistant forms of {beta}-catenin (CTNNB1) have been shown to be the main driver for many of these neoplasms. However, the underlying genetic driver for a proportion of these tumours is still unknown. Using murine transgenic models, we show that genetic disruption of the Wnt-antagonist and tumour suppressor, adenomatous polyposis coli (Apc), within the pituitary progenitors/stem cells, leads to pituitary tumours that closely resemble human aCPs. These tumours present classic histopathological hallmarks of aCPs, such as large deposits of wet keratin, stellar-reticular-like cells, large cystic components and clusters of accumulating nucleo-cytoplasmic {beta}-catenin that are slow-dividing and exhibit a secretory phenotype. We show that a hypomorphic allele of Apc is sufficient for tumour development, indicating that disruption of Apc function can lead to aCP formation. Moreover, we identify that bi-allelic loss of Apc in the Sox2+ve pituitary stem cells is sufficient to initiate tumour formation, indicating that Sox2+ve stem cells are the cell origin of these Apc-driven aCPs. Transcriptomic analyses of early tumour-initiating cells revealed that Apc-driven clusters of accumulating {beta}-catenin undergo senescence-associated secretory phenotype (SASP), which is p21-mediated and results in secretion of inflammasome, angiosome and developmental growth factors. Our data unequivocally show a causal role for the disruption of the tumour suppressor Apc as a primary driver of aCPs independent of mutations in {beta}-catenin. We provide murine models representing a novel genetic subtype of human aCPs offering insights into aCP pathogenesis. Our work reinforces the importance of genetic testing for mutations in APC in patients with aCPs and identifies a potential need to screen patients with familial adenomatous polyposis (FAP) or spectrum of APC-pathogenic syndromes for aCPs in early life.

cancer biology↗

bioRxiv2025

Modulation of specific interactions within a viral fusion protein predicted from machine learning blocks membrane fusion

Enveloped viruses must enter host cells to initiate infections through a fusion process, during which the fusion proteins undergo significant and complex structural changes from pre-fusion to post-fusion conformations. Understanding of the fusion protein conformational stability, rapid and accurate identification of the stabilizing interactions are critically important for inhibiting the infections. Here, we leverage molecular dynamics simulations, novel machine learning models and biological experiments to identify the crucial interactions dictating the structural stability of glycoprotein B (gB), a class III fusion protein. We focused on the interactions between the fusion loops and the membrane proximal region in gB, and a new Q181-R747 polar interaction was identified from our machine learning model as critical in stabilizing the gB pre-fusion conformation. Molecular simulations revealed that mutation of Q181 with proline (Q181P) disrupted the fusion loop secondary structure and reduced gB pre-fusion stability. Experiments were designed to evaluate the impact of the Q181P on fusion. Strikingly, the mutation completely abrogated gB membrane fusion activity. The experiments confirmed the importance of Q181-R747 interaction on fusion, which is consistent with the model predictions. The results deepen our fundamental understanding of the molecular mechanisms of gB during viral fusion, which may lead to novel antiviral interventions. The modeling and experimental framework can be generalized to rapidly identify the critical inter-molecular interactions in other important biological processes.

microbiology↗