Biology subjects

Ma, Y.

Publications and source records attributed to Ma, Y..

At least 91 records · Page 5Linked to original sources

bioRxiv2025

Tri-AD: Hippocampal cell-type-specific responses to age, sex and APOE genotype

Alzheimers disease (AD) risk is strongly shaped by age, sex, and the apolipoprotein E {varepsilon}4 (APOE4) allele--the strongest genetic risk factor for late-onset AD. While each factor has been studied independently, their combined impact on cellular and molecular processes remains unclear. Here, we used single-nucleus RNA sequencing (snRNA-seq) to profile hippocampal cell states in a sex-balanced cohort of human APOE4/4 and APOE3/3 knock-in mice across 6, 12, and 18 months of age. We identify sex as the major driver of variation in cell-type abundance and find that oligodendrocytes exhibit pronounced male-biased transcriptional sensitivity to APOE4. Differential expression and cell-cell communication analyses further reveal sex-divergent temporal trajectories in inhibitory neurons, with females showing early APOE4-associated suppression of synaptic pathways and males displaying a delayed but convergent decline. Together, these findings clarify how age, sex, and APOE genotype jointly regulate cell-type-specific gene expression and intercellular communication in the aging hippocampus, providing an innovative and publicly accessible database for aging and AD research and related precision medicine.

bioinformatics↗

bioRxiv2025

Sequence-context-aware decoding enables robust reconstruction of protein dynamics from crystallographic B-factors

While X-ray crystallography remains the primary source of protein structures, the B-factors associated with these coordinates are frequently obscured by crystal packing and refinement artifacts that limit their utility for quantifying solutionstate dynamics. We address the disparity between static structural abundance and dynamic information scarcity by introducing the B-Factor Corrector. This fine-tuned protein language model redefines B-factor analysis as a sequenceto-dynamics translation task rather than a purely physical calculation. By leveraging deep contextual embeddings to decouple intrinsic flexibility from lattice constraints, our model recovers ground-truth conformational fluctuations derived from structural ensembles and achieves a Pearson correlation of 0.80. We further demonstrate the utility of these sequence-inferred dynamics in structural biology applications where the model identifies binding-competent conformations for flexible molecular docking, unmasks cryptic mechanical hinges essential for chaperone function, and guides the energetic refinement of antibody interfaces to resolve steric conflicts. These results suggest that static crystallographic data can be effectively repurposed to decode accurate dynamic patterns latent within the Protein Data Bank.

biophysics↗

bioRxiv2025

A tailored in vivo CRISPR screen identifies BAP1 as a potent tumor suppressor of soft tissue sarcoma

Undifferentiated pleomorphic sarcoma (UPS) is one of the most common soft tissue sarcomas (STS) in adults. Despite decades of research, therapeutic advancements for STS, including UPS, have remained limited. The genetic complexity of UPS, characterized by the absence of recurrent driver oncogene mutations, has hindered the development of effective targeted therapies beyond conventional chemotherapy and immunotherapy. To address this challenge, we conducted a customized in vivo CRISPR/Cas9 screen in mice to systematically identify potential tumor suppressors involved in UPS development. Our screen revealed BRCA1-associated protein 1 (Bap1) as a potent tumor suppressor in STS. Using total RNA sequencing, multiplex immunohistochemistry, and flow cytometry, we found that Bap1-deficient mouse sarcomas exhibit significant immune suppression. Further analysis indicated that polo-like kinase 1 (Plk1) is essential for the survival of Bap1-deficient sarcomas. Treatment with volasertib, a Plk1 inhibitor, markedly inhibited tumor growth in both syngeneic and spontaneous mouse models of Bap1-loss sarcoma. In conclusion, our findings suggest that PLK1 inhibition, or combined with immunotherapy, may represent a promising targeted therapeutic strategy for tumors lacking BAP1.

cancer biology↗

bioRxiv2025

JADE: Joint Alignment and Deep Embedding for Multi-Slice Spatial Transcriptomics

As spatially resolved transcriptomics (SRT) datasets increasingly span multiple adjacent or replicated slices, effective joint analysis across slices is needed to reconstruct tissue structures and identify consistent spatial gene expression patterns. This requires resolving spatial correspondences between slices while capturing shared transcriptomic features, two tasks that are typically addressed in isolation. Multi-slice analysis remains challenging due to physical distortions, technical variability, and batch effects. To address these challenges, we introduce Joint Alignment and Deep Embedding for multi-slice SRT (JADE), a unified computational framework that simultaneously learns spatial location-wise alignments and shared low-dimensional embeddings across tissue slices. Unlike existing methods, JADE adopts a roundtrip framework in which each iteration alternates between alignment and embedding refinement. To infer alignment, we employ attention mechanisms that dynamically assess and weight the importance of different embedding dimensions, allowing the model to focus on the most alignment-relevant features while suppressing noise. To the best of our knowledge, JADE is the first method that jointly optimizes alignment and representation learning in a shared latent space, enabling robust multi-slice integration. We demonstrate that JADE outperforms existing alignment and embedding methods across multiple evaluation metrics in the 10x Visium human dorsolateral prefrontal cortex (DLPFC) and Stereo-seq axolotl brain datasets. By bridging spatial alignment and feature integration, JADE provides a scalable and accurate solution for cross-slice analysis of SRT data.

bioinformatics↗

bioRxiv2025

Diffusion-based Representation Integration for Foundation Models Improves Spatial Transcriptomics Analysis

MotivationWe propose DRIFT, a framework that integrates spatial context into the input representations for foundation models by leveraging diffusion on spatial graphs derived from spatial transcriptomics (ST) data. ST captures gene expression profiles while preserving spatial context, enabling downstream analysis tasks such as cell-type annotation, clustering, and cross-sample alignment. However, due to its emerging nature, there are very few foundation models that can utilize ST data to generate embeddings generalizable across multiple tasks. Meanwhile, well-documented foundational models trained on large-scale single-cell gene expression (scRNA-seq) data have demonstrated generalizable performance across scRNA-seq assays, tissues, and tasks; however, they do not leverage the spatial information in ST data. We use heat kernel diffusion to propagate embeddings across spatial neighborhoods, incorporating the local neighborhood context of the ST data while preserving the transcriptomic representations learned by state-of-the-art single-cell foundation models. ResultsWe systematically benchmark five foundational models (both scRNA-seq and ST-based) across key ST tasks such as annotation, alignment, and clustering, ensuring a comprehensive evaluation of our proposed framework. Our results show that DRIFT significantly improves the performance of existing foundational models on ST data over specialized state-of-the-art methods. Overall, DRIFT is an effective, accessible, and generalizable framework that bridges the gap toward universal models for modeling spatial transcriptomics. Availability and ImplementationCode and data available at https://github.com/rsinghlab/DRIFT. Contactritambhara@brown.edu Supplementary informationSupplementary notes are provided with the manuscript.

bioinformatics↗

bioRxiv2025

Resolving Heterogeneity in Major Depression: Overcoupling and Undercoupling Subtypes Exhibit Differential Treatment Response and Molecular Pathways

Major depressive disorder (MDD) exhibits significant heterogeneity whose neurobiological mechanisms remain elusive. Alterations in morphological-functional coupling (MFC) have been observed in MDD. This study aims to investigate MDD subtypes based on MFC alterations and their associations with clinical symptoms and molecular basis. We identified two clinically distinct MDD subtypes in multi-center neuroimaging data (Discovery: 828 MDD/776 healthy controls; Validation: 236 MDD/86 healthy controls) by using a semi-supervised machine learning approach based on MFC changes, which were validated and robustly repeated in the validation dataset. Differences among subtypes were then examined in relation to clinical assessments, gene expression patterns, neurotransmitter and cell density, and treatment response. Subtype I (overcoupling) showed elevated MFC in high-order association cortices, linking to synaptic transmission activity and severe symptoms. Subtype II (undercoupling) demonstrated reduced MFC in primary cortices, associated with cell cycle regulation and treatment resistance. Both subtypes shared molecular signatures (cell types: astrocytes and oligodendrocytes; neurotransmitter systems: serotonergic and GABAergic receptors). Crucially, longitudinal data (33 MDD undergoing Escitalopram monotherapy) revealed that undercoupling subtype exhibited better response, implying a potential mechanism of the drug via increasing the MFC. Our work deciphers MFC-driven MDD phenotypes with distinct molecular profiles and differential treatment outcomes, suggesting potential pathways for personalized diagnosis and treatment strategies in MDD, advancing precision psychiatry.

neuroscience↗

bioRxiv2025

Palmitoylation of death receptor p75NTR contributes to Alzheimer's Disease progression by regulating APP trafficking and degradation

Although protein palmitoylation has been associated with Alzheimers Disease (AD), it remains unclear whether or how palmitoylation of specific proteins contributes to any of the pathological features of AD. The p75 neurotrophin receptor (p75NTR) contributes to AD progression by regulating the intracellular trafficking and amyloidogenic processing of amyloid precursor protein (APP). p75NTR is palmitoylated at a juxtamembrane cysteine but it is currently unknown whether this has any effect on its role in AD. Here, we report that 5xFAD mice, an animal model of AD, expressing a palmitoylation-deficient mutant of p75NTR (p75C281A) display significantly attenuated neuropathology and cognitive deficits. p75C281A showed enhanced internalization, trafficking to Rab5/Rab7 endosomes and lysosomal-mediated degradation. In mutant p75C281A neurons, APP displayed accelerated co-internalization with p75NTR, increased trafficking to late endosomes and lysosome, and enhanced degradation, thereby limiting neuronal A{beta} production. Interestingly, the brain of 5xFAD mice shows increased levels of p75NTR palmitoylation. These results indicate that palmitoylation of p75NTR enhances its stability and, indirectly, that of APP by reducing their trafficking to the lysosome, resulting in increased A{beta} accumulation and neuropathology in the AD brain. Selective inhibitors of p75NTR palmitoylation may find applications in the treatment of AD

neuroscience↗

bioRxiv2025

From Signal to Symphony: Exploring 2D Sequence Representations for Protein Function Prediction

Predicting protein function from its primary sequence is a fundamental challenge in computational biology. While deep learning has excelled, the optimal representation of sequence data remains an open question. This study explores protein sonification--the conversion of amino acid sequences into 2D spectrograms--as a representation for this task. To facilitate this investigation, we developed a benchmark dataset of 18,000 sequences spanning 12 functionally diverse protein classes. Our systematic evaluation suggests that the structural transformation from a 1D sequence to a 2D spectrogram may be a key contributor to the models predictive performance. This observation is supported by ablation studies where models using either purely visual or acoustic features from the spectrogram demonstrated effective standalone performance, suggesting that the representation itself is a key source of this capability. For instance, a model using a sonification map without explicit biophysical meaning achieved 81.08% accuracy, while our biophysically-informed model reached 84.00%, indicating that such domain knowledge may offer a modest performance benefit. When trained from scratch on our dataset, our fusion model achieved performance comparable to or slightly exceeding that of standard transformer architectures like ESM-2 and ProtBERT, suggesting its potential for data efficiency in this specific context. The models potential for generalizability was further supported by its performance on the external CARE enzyme classification benchmark, where it achieved 90.44% accuracy. Finally, as a proof-of-concept, we explore the utility of our encoding to guide a diffusion model in generating novel GFP variants, which were assessed for structural viability using computational methods. Our work provides evidence suggesting that the utility of sonification in this context may stem largely from its representational structure, offering a perspective on feature engineering for biological sequences.

bioinformatics↗

bioRxiv2025

Deep multiplexed 50-marker imaging of circulating tumor cells expands actionable biomarker profiling for precision oncology

Liquid biopsy-derived circulating tumor cells (CTCs) offer a minimally invasive avenue for precision oncology by enabling longitudinal monitoring of actionable molecular and cell-phenotypic biomarkers. However, conventional immunofluorescence imaging-based CTC profiling captures just 4-5 markers per cell, restricting crucial insights into oncogenic and resistance drivers, as well as tumor cell heterogeneity. Here we present an integrated pipeline employing deep multiplexed imaging to profile up to 50 molecular markers per CTC, capturing expression, phosphorylation, and subcellular localization of diverse biomarkers. Validated in a multi-stage prostate cancer resistance model and applied to prostate cancer patient-derived CTCs, this approach enhances CTC classification and reveals inter- and intra-patient heterogeneity correlating with therapy response. Machine learning identified therapeutically actionable signatures, suggesting patient-specific treatment strategies. This deep multiplexed imaging pipeline advances the utility of CTCs in guiding personalized cancer therapy by providing comprehensive molecular and phenotypic insights through minimally invasive liquid biopsies. Highlights- Multiplexed immunofluorescence imaging of circulating tumor cells captures up to 50 molecular markers per cell with subcellular localisation. - Single-cell and subcellular analyses identify quantitative signatures correlating with patient outcome, as well as therapeutically actionable biomarkers. - This method transforms the utility of CTCs for future use in patient stratification and for guiding personalised therapies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/684075v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@a36ff4org.highwire.dtl.DTLVardef@b06c1org.highwire.dtl.DTLVardef@1e8a572org.highwire.dtl.DTLVardef@c60753_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

cancer biology↗

bioRxiv2025

A cocktail of SARS-CoV-2 spike stem helix domain and receptor binding domain human monoclonal antibodies prevent the emerge of viral escape mutants

Neutralizing antibodies (NAbs) targeting the spike (S) glycoprotein remain a crucial therapeutic strategy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, emerging viral variants have escaped all Food and Drug Administration (FDA)-approved NAb treatments, underscoring the urgent need for effective therapeutic alternatives. Using a nanoluciferase (Nluc)-expressing attenuated recombinant SARS-CoV-2 lacking the open reading frames (ORF) 3a and 7b ({Delta}3a7b-Nluc), we characterized resistance profiles of two broadly protective NAbs targeting the S receptor binding domain (RBD) in S1 (1301B7) and the stem helix domain (SH) in S2 (1249A8). Serial passaging of {Delta}3a7b-Nluc under selective pressure identified a 1301B7 antibody-resistant mutants (ARM-B7) harboring an RBD mutation (S371F) that conferred resistance to 1301B7 and other RBD-directed NAbs (Casirivimab, SC27 and Sotrovimab). In contrast, no ARM emerged under treatment with 1249A8, or an antibody cocktail of 1301B7 (RBD) + 1249A8 (SH). These findings demonstrate that S2 SH-targeting NAbs shows higher genetic barrier to resistance than S1 RBD-targeting NAbs, and that a NAbs cocktail therapy targeting the SARS-CoV-2 S1 RBD and S2 SH offers the most effective strategy to prevent the emergence of escape mutations. Together, our findings provide critical insights into developing next-generation resistance-evading NAb therapies against SARS-CoV-2, and potentially other coronaviruses, and demonstrate the value of using our attenuated viral platforms for the safe identification of ARM without the potential biosafety concerns of doing these experiments using wild-type (WT) forms of SARS-CoV-2. SIGNIFICANCEThe clinical efficacy of early SARS-CoV-2 NAbs has been challenged by the emergence of escape viral variants, highlighting an urgent need to anticipate resistance. Using a luminescent attenuated SARS-CoV-2 platform, we profiled resistant mutations against two broadly protective SARS-CoV-2 NAbs. Passage of {Delta}3a7b-Nluc in the presence of a NAb targeting the RBD S1 domain (1301B7) readily selected for an ARM, whereas passage in the presence of an SH S2 domain NAb (1249A8) did not. Notably, a cocktail of 1301B7 and 1249A8 created a high barrier of selecting SARS-CoV-2 ARM, preventing the emergence of resistant variants. We identified an S371F mutation in the S1 RBD of ARM-B7 that confers resistance to 1301B7 and other S1 RBD-targeting NAbs. These results highlight the importance of combination therapies targeting both variable RBD S1 and conserved SH S2 domain for the efficient treatment of SARS-CoV-2 and to prevent the emerge of NAb-induced escape mutations.

microbiology↗

bioRxiv2025

Industrialization drives convergent microbial and physiological shifts in the human metaorganism

Understanding how host lifestyle and industrialization shape the human gut microbiome and intestinal physiology requires multimodal analyses across diverse global host contexts. Here, we generate multivariate data from the Global Microbiome Conservancy cohort, including gut microbiome, IgA-sequencing, host genotyping, diet, lifestyle and fecal biomarker profiles, to investigate host-microbiome interactions across gradients of industrialization and geography. We show that industrialization is associated with homogenized microbial compositions, reduced microbial diversity, and lower community stability, independent of host confounders. We further show that industrialization is linked to elevated markers of gut stress, increased IgA secretion, and altered patterns of IgA-bacteria interactions. Finally, we show that microbiome-based disease predictors trained on industrialized populations lose accuracy in less industrialized cohorts, highlighting limited cross-population transferability. Together, our results suggest profound restructuring of host-microbiome interactions due to industrialized lifestyles, and emphasize the need for inclusive, globally representative data to improve translational microbiome applications across diverse human populations.

microbiology↗

bioRxiv2025

Antiviral reverse transcriptases reveal the evolutionary origin of telomerase

Defense-associated reverse transcriptases (DRTs) employ diverse and distinctive mechanisms of cDNA synthesis to protect bacteria against viral infection. However, much of DRT family diversity remains unstudied. Here we identify a new antiviral defense system, DRT10, that associates with a non-coding RNA (ncRNA) to catalyze processive, protein-primed synthesis of tandem-repeat DNA. Repeat addition is dictated by sequence and structural features of the ncRNA that have direct parallels in the RNA component of telomerase. Remarkably, a phylogenetic analysis of RTs across domains of life reveals an unexpected link between DRT10 and telomerase that is further supported by structural comparisons and mechanistic evidence. These findings expand the repertoire of reverse transcription mechanisms in antiviral defense and point to a bacterial origin for telomerase. One-Sentence SummaryInsights from antiviral defense systems reveal an unexpected bacterial origin for the mechanism of chromosome maintenance by eukaryotic telomerase.

molecular biology↗

bioRxiv2025

Targeting Endothelial PERK Accelerates Lymphoid Regeneration by Enhancing DLL4-NOTCH3 Signaling at the Pre-B Niche

Delayed immune recovery after hematopoietic stem cell (HSC) transplantation is associated with a poor clinical outcome, yet strategies to enhance lymphocyte regeneration are limited. We studied the role of unfolded protein response (ER stress) in hematopoietic regeneration within the bone marrow (BM) microenvironment. We revealed that PERK activation is a prominent feature of BM endothelium in leukemia patients and is a hallmark response in mouse BM following ionizing irradiation. Ablating endothelial Perk boosted Notch ligand DLL4 expression and promoted DLL4-dependent early HSC and B progenitor regeneration. Single-cell analysis shows that endothelial DLL4 activates NOTCH3 expressed by mesenchymal stroma cells, and that the PERK-DLL4 axis coordinates the regulation of lymphoid commitment and niche cytokine production. NOTCH3 is critical for the upregulation of IL7 following irradiation and for supporting the expansion of lymphoid progenitors in mesenchymal sphere cultures. These findings not only unveil a previously unrecognized ER stress-controlled vascular-stroma signaling mechanism in regenerative hematopoiesis but also highlight PERK blockade as a promising therapeutic strategy to improve immune recovery after myeloablative transplantation. SummaryZou et al unravel that the adaptive ER stress response in bone marrow blood vessels restricts the post-transplant regeneration of immune progenitor cells by attenuating the expression of Notch ligand DLL4. Targeting ER stress sensor PERK can accelerate immune recovery after transplantation by enhancing DLL4-NOTCH3 signaling and IL7 cytokine production.

cell biology↗

bioRxiv2025

Identification and characterization of a SARS-CoV-2 Mpro G23 deletion ensitrelvir-resistant mutant

Ensitrelvir is an antiviral drug that specifically targets the main protease (Mpro) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been approved for the treatment of coronavirus disease 2019 (COVID-19) due to the conservation of its target protein which is essential in the viral lifecycle. However, SARS-CoV-2 could introduce mutations in the viral proteins to confer resistance to antivirals. Thus, screening for drug-resistant SARS-CoV-2 mutants and elucidating their resistant mechanisms are critical for guiding the selection of effective antiviral therapies. Here, we utilized a luminescent attenuated SARS-CoV-2 ({Delta}3a7b-Nluc WT) to safely identify ensitrelvir drug-resistant mutants (DRM-E) without the need of using virulent forms of SARS-CoV-2. We isolated a DRM-E containing a G23 deletion (G23del) in Mpro with high resistance (>1,000 fold) to ensitrelvir, but not to the other Mpro inhibitor (nirmatrelvir) or to the RNA-dependent RNA polymerase (RdRp) inhibitor remdesivir. The contribution of G23del was confirmed by generating a recombinant luminescent attenuated SARS-CoV-2 containing G23del in the non-structural protein 5 (NSP5) gene ({Delta}3a7b-Nluc G23del). {Delta}3a7b-Nluc G23del exhibited significant resistance to ensitrelvir in both cultured cells an in K18 hACE2 transgenic mice. Binding affinity revealed that G23del mutation substantially altered Mpro binding affinity for ensitrelvir but not nirmatrelvir. In conclusion, our results demonstrate that G23del in Mpro can confer high resistance to ensitrelvir. Positively, G23del in Mpro does not render SARS-CoV-2 resistant to nirmatrelvir or remdesivir, suggesting the feasibility of treating infections with SARS-CoV-2 containing G23del with these other approved antivirals. SIGNIFICANCEThe clinical use of SARS-CoV-2 antiviral drugs is increasingly challenged by the emergence of drug-resistant mutants. Thus, there is a pressing need to identify and characterize antiviral escape SARS-CoV-2 variants, particularly for FDA-approved antivirals. Our study addresses this by employing a luminescent attenuated virus platform ({Delta}3a7b-Nluc WT) to safely identify and characterize resistance mutations without the concern of using virulent forms of SARS-CoV-2. Using this safe approach, we have identified a G23 deletion (G23del) in SARS-CoV-2 Mpro, which mediates resistance to ensitrelvir in vitro and in vivo. Importantly, while G23del was able to confer more than 1,000-fold increased resistance to ensitrelvir, SARS-CoV-2 containing G23del remained sensitive to other Mpro (nirmatrelvir) and RdRp (remdesivir) inhibitors. Altogether, this study demonstrates the feasibility of using {Delta}3a7b-Nluc to safely identify and characterize drug resistant viruses without the biosafety concern of using virulent SARS-CoV-2 and advance the design of next-generation antiviral drugs.

microbiology↗

bioRxiv2025

Engineering magnetically guided bacteriophages for precision antimicrobial therapy and targeted biofilm eradication

Viruses, including bacteriophages, rely on passive diffusion to reach their hosts, limiting the efficacy of virus-based therapies and leading to off-target accumulation with systemic effects. Here, we present a strategy to confer controllable motility to bacteriophages by incorporating iron nanoparticles (FeNPs) into their head structures while preserving infectivity. Cryo-electron microscopy (Cryo-EM) and transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) confirmed the FeNP presence in the phages head. FeNP-tagged phages can be magnetically enriched and isolated from bacterial prey cultures, eliminating the need for ultracentrifugation. Under magnetic guidance, these engineered phages exhibit rapid and directed movement through complex microenvironments, including mazes and polymer barriers, enabling precise bacterial targeting and biofilm eradication in a microfluidic system. In an in vivo wound infection model, magnetically guided phages successfully navigated from the peritoneum to the biofilms on the wound, thus selectively eliminating biofilms while minimizing systemic exposure to other organs. Hence, our approach confers viral mobility, thus enhancing the precision and efficacy of bacteriophage-based biotechnological and therapeutic applications.

microbiology↗

bioRxiv2025

Gut Microbiota Modulates and Predicts Disease Severity in Experimental Pemphigoid Disease

Pemphigoid diseases (PD) are autoimmune blistering diseases with reported alterations in skin and gut microbiota, though their causal contribution to disease pathophysiology remains unclear. Using a passive model of bullous pemphigoid-like epidermolysis bullosa acquisita (BP-like EBA), we compared C57BL/6J mice from two sources (in-house vs. Charles River) that differed in their baseline microbiota. Charles River mice developed significantly less severe disease. Co-housing led to partial homogenization of the gut microbiota, driven by asymmetric transfer of taxa from Charles River to in-house mice, which corresponded with reduced disease severity in the latter. The skin microbiota, however, showed limited exchange. Disease severity was inversely associated with gut microbial alpha diversity, with protective taxa such as Lactobacillus intestinalis and Parabacteroides distasonis enriched in Charles River mice, while pro-inflammatory taxa including Turicimonas muris and Muribaculum intestinale were enriched in in-house mice. A machine learning model further identified a gut taxon most closely matching the candidate genus Scatocola as a strong negative predictor of disease severity. Through experimental exposure and uptake of variable gut microbiota, these findings suggest a direct role of gut microbiota in mediating the severity of the experimental BP-like EBA and highlight the potential of microbiota-based strategies for therapeutic intervention in PD.

microbiology↗

bioRxiv2025

Bile Salts and Bacterial Bile Salt Hydrolase Activity Differentially Influence Escherichia coli Colonization and FXR Signaling in Colorectal Cancer Organoids

Bile salts are key regulators of host-microbe interactions and epithelial signaling in the intestine. Gut bacteria can deconjugate primary bile salts, which can be leveraged to engineer targeted therapies through bile salt hydrolase (BSH) activity. However, the interplay between bile salt signaling, microbial metabolism, and tumor-associated colonization remains poorly understood. Here, we establish an in vitro colon organoid platform to dissect bile salt-driven epithelial-microbe dynamics at cellular resolution. Using this system, we found that bile salts markedly modulated colonization of native Escherichia coli (EcAZ-2) and a BSH-expressing strain (EcAZ-2LsBSH) in healthy versus tumor murine organoids. Under bile salt exposure, EcAZ-2LsBSH preferentially colonized tumor organoids, though overall colonization was lower than that of the non-BSH strain. Beyond effects on bacterial colonization, bile salts also directly activated host signaling pathways. In presence of bile salts, EcAZ-2LsBSH significantly enhanced activation of bile acid receptors such as farnesoid X receptor (FXR) by 2-fold in healthy organoids. These findings reveal a mechanistic bridge between in vivo microbial function and bile salt interactions, offering potential microbiota and bile acid targeted therapeutic strategies.

cancer biology↗

bioRxiv2025

Sarbecovirus Rc-o319 S-Protein Structures Reveal Highly Specialized Adaptation to Rhinolophus cornutus ACE2

Bat sarbecoviruses often exhibit species-dependent ACE2 specificity. Understanding the determinants of receptor specificity enables better assessment of the cross-species transmission potential of sarbecoviruses. Here, we characterize the S-protein of Rc-o319, a sarbecovirus identified in Japanese Rhinolophus cornutus bats. Featuring an unusual 9-amino-acid deletion within its receptor binding motif (RBM), Rc-o319 S-protein utilizes its cognate R. cornutus ACE2 (bACE2R.cor) but not human ACE2 (hACE2), demonstrating highly restricted receptor specificity. Cryo-EM structures reveal two locked prefusion conformations of the Rc-o319 S-trimer and define a novel type-1b receptor-binding domain (RBD), featuring a distinct beta-loop (BL) within the RBM due to the RBM-deletion. The Rc-o319-RBD:bACE2R.cor complex structure reveals unique interactions mediated by the specialized BL and RBM-loop of Rc-o319-RBD and by a bACE2R.corglycan. Structure-guided mutagenesis demonstrates that changes in BL and RBM-loop within the Rc-o319 S-RBD must occur simultaneously to allow medium-to-high-affinity hACE2 binding. Comparative assays further show that the bACE2R.cor receptor supports only a subset of sarbecoviruses, highlighting its restricted sarbecovirus compatibility. Our findings establish the Rc-o319 S-protein as a structurally and functionally specialized adaptation to R. cornutus ACE2 and identify the structural constraints limiting its cross-species transmission potential. Author SummarySARS-related viruses are widely found in horseshoe bats. Some can bind the human ACE2 receptor with variable affinities, whereas others bind only bat ACE2 receptors. Understanding the basis for this difference is critical for assessing spillover risk. We studied the spike protein of a bat sarbecovirus, Rc-o319, isolated from Japanese Rhinolophus cornutus horseshoe bats. Although Rc-o319 is genetically related to SARS-CoV-2, it is unable to bind the human ACE2 receptor. Structural analyses and functional experiments revealed that the Rc-o319 spike protein possesses a distinct receptor-binding motif (RBM). This RBM features a specialized "beta-loop" that replaces the "large-loop" found in human-infecting sarbecoviruses. The beta-loop enables high-affinity binding to its cognate Rhinolophus cornutus bat ACE2 receptor while simultaneously preventing optimal interaction with human ACE2. We further found that acquisition of high affinity for the human ACE2 receptor would require coordinated changes across multiple regions of the RBM, including changing the beta-loop into a large-loop structure. Together, our findings demonstrate that the Rc-o319 spike protein is highly adapted to its cognate bat ACE2 receptor and faces substantial structural constraints that limit its ability to switch to binding human ACE2.

microbiology↗