Biology subjects

Dong, T.

Publications and source records attributed to Dong, T..

At least 19 recordsLinked to original sources

bioRxiv2026

Distinct spatial organization of human hippocampal perfusion and microvascular pulsatility across age

Arterial pulsation can modulate neuronal activity through mechanosensitive pathways in mice, but whether vascular pulsatility is similarly related to neural organization in humans remains unclear. Here, using 7T MRI in 35 young and older adults, we mapped cerebral perfusion and microvascular volumetric pulsatility index (mvPI) across the unfolded hippocampus and integrated these measures with histological, electrophysiological, and transcriptomic reference maps. Perfusion and mvPI exhibited distinct spatial organization and age-related differences. In young adults, perfusion preferentially corresponded to parvalbumin-interneuron density and beta/gamma distribution, whereas mvPI was associated with theta-band distribution. A number of associations detected in young adults were not detected in the older adults maps. Spectral simulations showed qualitative similarity to heartbeat-related phase resetting as one possible explanation for the mvPI-theta relationship, while spatial transcriptomics revealed perivascular enrichment of PIEZO2, a candidate mediator of vascular mechanotransduction. Together, these findings establish perfusion and tissue-level pulsatility as distinct dimensions of human hippocampal vascular organization and provide a framework for investigating their relationships with neural dynamics across aging.

neuroscience↗

bioRxiv2026

ClonoDeconv: reference-based α - β paired recurrent clonotype proportion estimation from bulk-TCR sequencing

T cell receptor (TCR) sequencing is crucial when studying antigen-specific T cell responses and clonal dynamics. A key objective of TCR repertoire analysis is to identify recurring clonotypes across timepoints or different disease states, providing insight into the evolution of immune response. Bulk-TCR sequencing enables high-throughput profiling of TCR and {beta} sequences but lacks pairing information, while single cell TCR sequencing (scTCR-seq) retains pairing information but is limited by sensitivity, throughput, and costs. We present ClonoDeconv, a computational framework to deconvolute paired TCR {beta} ; clonotype frequency from bulk TCR sequencing experiments using a paired scTCR-seq reference. ClonoDeconv robustly estimated shared clonotype abundances from 5' RACE bulk-TCR datasets using a scTCR-seq reference from the same donor. Applied to longitudinal samples, ClonoDeonv successfully captured the expansion and contraction of rare virus-specific clones across timepoints. Taken together, ClonoDeconv provides a cost-effective and scalable approach for studying the longitudinal T-cell clonal dynamics.

bioinformatics↗

bioRxiv2026

A genome-scale ORF screen for resilience factors that protect the RPE and restore vision in aged mice

Aging is a complex phenomenon, yet therapeutic discovery has largely relied on testing individual hypothesis-driven targets. Here, we performed a genome-scale open reading frame (ORF) screen for oxidative-stress resistance in retinal pigment epithelium (RPE) cells, which are vulnerable to oxidative damage during aging. The screen identified nine protective ORFs including antioxidant factors and an epithelial-to-mesenchymal transition regulator. Notably, we also identified three factors that reduce transcriptomic age including the cardiac transcription factor NKX2-5. NKX2-5 conferred robust oxidative resilience in vitro and in vivo. Domain dissection revealed that its homeodomain is dispensable for resilience, enabling development of NKX2-5{Delta}HD, which retained protective activity without detectable toxicity over 14 months. In middle-aged mice, subretinal NKX2-5{Delta}HD restored visual and electrophysiological function, and its systemic delivery improved grip strength and reduced frailty in late-aged mice. These findings highlight the value of unbiased, genome-scale gain-of-function screening, as resilience factors normally expressed in other contexts can be reengineered as potential therapeutics for age-related decline in other tissues.

genetics↗

bioRxiv2026

Mode of T cell priming durably shapes the TCR repertoire, effector function and α4β1 integrin expression of human virus-specific CD4+ T cells

The generation of an effective T cell response against an antigen depends on the recognition of the antigen by the T cell receptor (TCR), followed by T cell priming, initiating coordinated biophysical, biochemical and proliferative changes that drive differentiation into effector and memory clones. The immunological environments in which priming occurs, such as natural infection or vaccination, influences the quality and persistence of memory T cells, but the long-term impacts remain incompletely understood. Here, we investigate how the mode of priming shapes durable antigen-specific CD4+ T cell memory, utilising two cohorts 3-4 years after initial antigen encounter: individuals recovered from SARS-CoV-2 infection and infection-naive individuals who received a SARS-CoV-2 vaccination. Using ex vivo single-cell RNA sequencing, paired TCR sequencing and in vitro functional analyses, we characterise the transcriptional, clonal and functional profile of Spike-specific CD4+ T cells. Across both cohorts, CD4+ T cell responses against spike epitopes S166-180, S751-765 and S866-880, were immunodominant, with shared public TCR clonotypes indicating conserved antigen-recognition regardless of mode of priming. Despite this shared specificity, infection-primed individuals exhibited greater TCR repertoire diversity and lower CDR3{beta} sequence convergence. Transcriptionally, infection-primed cells exhibited a more cytotoxic and effector phenotype, while vaccine-primed cells preferentially adopted T follicular helper (Tfh)- and Th1-associated phenotypes. Infection-primed individuals also displayed enrichment of cell adhesion and integrin signalling pathways, with a greater proportion of spike-specific CD4+ T cells expressing 4{beta}1 integrin subunits, consistent with enhanced migratory and effector potential. Collectively, our findings demonstrate that the mode of antigen priming may influence the long-term CD4+ T cell memory states, influencing TCR repertoire diversity, functional differentiation and tissue-homing potential, years after the initial immune response.

immunology↗

bioRxiv2026

The Central Nucleus of the Amygdala Encodes the Motivation to Pursue Ethanol

Prior studies implicate the central nucleus of the amygdala (CeA) in reward motivation, yet how this region encodes motivation for ethanol (EtOH) seeking and consumption-and how this compares to encoding of natural rewards--remains poorly understood. We recorded single-unit neural activity from rats during a cued instrumental task in which lever insertion on each trial indicates the opportunity to lever press for ethanol and post-press lever retraction signals ethanol delivery. We found neurons responsive to multiple trial events (lever insertion and retraction cues, lever press, port entry, and reward licks), including neurons with rhythmic activity entrained to licking during EtOH consumption. Notably, CeA neural responses to the lever insertion cue at trial start encoded both the likelihood and speed of engagement during reward seeking. Using a supervised classifier, we found that trial engagement and motivation level could be decoded from pre-trial and lever insertion response periods. Finally, we assessed whether these effects generalized to natural reward seeking. Sucrose-rewarded rats (both ethanol-exposed and ethanol-naive) showed higher motivation (more rewards earned and shorter first-press latencies) and stronger CeA recruitment and responses at lever insertion than ethanol-rewarded rats, in agreement with the notion that CeA circuits amplify reward-predictive cue signals to facilitate rapid action initiation under high motivational states. Together, these findings indicate that CeA neurons dynamically encode motivational states, with tonic activity and reward-predictive cue responses predicting both engagement in reward seeking and the vigor of action initiation. We suggest these patterns of neural activity drive ethanol and sucrose pursuit. Significance StatementHow motivational states drive reward-seeking is a central question in systems neuroscience, yet the mechanisms linking neural signals to action initiation remain poorly understood. Recording single-unit activity in the amygdala central nucleus (CeA) during cued ethanol self-administration revealed that neural responses to reward-predictive cues encoded both the decision to engage in reward seeking and the vigor of action initiation, and motivational state was decoded from cue-evoked signals and tonic activity even before cue presentation. Consistent with greater motivation for the more palatable sucrose reward, CeA neurons showed stronger cue responses and greater anticipatory firing preceding tongue contact with reward, compared with ethanol-rewarded rats. These findings identify CeA activity patterns that link motivational state to the rapid initiation of goal-directed action.

neuroscience↗

bioRxiv2026

Community assembly explains invasion differences between two contrasting forest types

Plant communities within a metacommunity can vary widely in their degree of invasion by introduced species. Disturbance, propagule pressure, and biotic resistance are common explanations for this variation, but empirical evidence for these hypotheses is mixed. Alternatively, the community assembly framework predicts that local assembly filters determine both native and exotic composition, but lower trait variation in the introduced species pool may exclude them from certain sites. We examined evidence for this framework using observational data from forests and woodlands of Long Island, NY, USA. These forests vary in vegetation composition and invasion along a soil gradient. They are also highly disturbed and fragmented, yet some stands have almost no introduced plants. Using data collected in 1998 and 2021-22, we quantified relationships between community composition, soil characteristics, and functional traits for native and exotic assemblages, as indicators of environmental filtering. We found similar trait-environment relationships in native and introduced species, suggesting that both groups follow the same local assembly rules. Introduced species were predominantly found in sites with more nutrient-rich soils and were absent from sites with nutrient-poor soils. At the regional scale, the exotic species pool was biased toward trait values favored in more nutrient-rich environments, particularly high growth rates and low leaf C:N ratios, which explains their absence from nutrient-poor environments. These patterns were consistent over time, and stands that were uninvaded in 1998 remained so in 2021-22, supporting the robustness and reliability of short-term studies. This study shows that invasion patterns in plant communities can be explained by the assembly rules that govern native species. By linking local environmental filtering with regional species pool characteristics, this work advances our understanding of how some communities remain uninvaded despite high disturbance and propagule pressure. Overall, these results highlight the utility of the community assembly framework, and emphasize the importance of regional processes in constraining the local distribution of introduced species.

ecology↗

bioRxiv2026

Functional activation reveals a repressor-gated fourth type VI secretion system in clinical Pseudomonas aeruginosa

Pseudomonas aeruginosa is a major opportunistic pathogen in which the type VI secretion system (T6SS) contributes to interbacterial competition and virulence. While most strains encode three T6SSs, we here functionally characterize a fourth system (H4-T6SS) in a clinical P. aeruginosa isolate. The H4-T6SS gene cluster is transcriptionally silent under laboratory conditions. By promoter rewiring, we demonstrate that the H4-T6SS assembles a contractile machine and mediates effector secretion and robust inter- and intraspecific antagonism. We identify a dominant pore-forming effector and its secretion pathway and a silent yet conserved nuclease effector. Genetic and biochemical analyses show that H4-T6SS expression is activated by an H4-encoded transcriptional regulator and repressed by H-NS family proteins. Analysis of over 1,200 clinical isolates reveals that the H4-T6SS is distributed across lineages and geographic regions. Finally, we observe functional crosstalk between H4- and H2-T6SSs. Together, these findings establish H4-T6SS as a functional and repressor-gated secretion system that expands the competitive arsenal of clinical P. aeruginosa.

microbiology↗

bioRxiv2025

Uncovering structural determinants of peptide recognition by public and private T-cell receptors

Public T cell receptors (TCRs) recurrently emerge across individuals in response to common pathogens, yet the structural and biophysical basis distinguishing public from private clonotypes remains incompletely defined. Here, we combine epitope mapping, single-cell TCR sequencing, and single-particle cryo-electron microscopy to dissect CD8+ T cell responses to the immunodominant SARS-CoV-2 ORF3a(207-215) epitope presented by HLA-A*01:01. Among responding clonotypes, we identify a shared public TCR (TCRpub) and an individual-specific private TCR (TCRpriv) that use nearly identical TRBV5-1 {beta} chains but distinct chains. Both clonotypes exhibit comparable micromolar affinity and functional avidity, yet their structures reveal different antigen-recognition modes. We determined cryo-EM structures of the TCRpub and TCRpriv in complex with ORF3a(207-215)/ HLA-A*01:01 at [~]3 [A] resolution. Despite targeting the same epitope, the two receptors engaged the peptide-MHC complex with distinct CDR-loop orientations and contact footprints: TCRpub engages the peptide through a peptide-centric AGDL CDR3{beta} motif and focuses interactions on the MHC 2-helix, whereas TCRpriv distributes contacts across both MHC -helices via a canonical CDR3{beta} configuration. These findings illustrate how near-identical {beta} chains can yield divergent recognition strategies to recognise the same pMHC ligand through alternative -chain pairing. More broadly, this work establishes cryo-EM as a robust approach for resolving physiological-affinity TCR/pMHC complexes, providing mechanistic insight into how public TCRs emerge and persist in antiviral immunity.

immunology↗

bioRxiv2025

Reprogrammed SimCells for Antimicrobial Therapy

Antimicrobial resistance (AMR) is a critical global health challenge. In this study, we developed a novel platform based on chromosome-free and non-replicating simple cells (SimCells, size 1-2 {micro}m) and mini-SimCells (size 100-400 nm) for targeted pathogen elimination. Engineered with surface-displayed nanobodies, SimCells and mini-SimCells selectively bind bacteria expressing specific antigens (e.g., OmpA in E. coli). The selective interactions facilitate close SimCell-pathogen proximity, enabling two antimicrobial mechanisms: direct injection of toxic effectors into bacterial cytoplasm via a heterologous expression of type VI secretion system (T6SS), and enzymatic conversion of aspirin into catechol by engineered salicylate hydroxylase, leading to sustained local production of hydrogen peroxide (H2O2). Our results demonstrate that both reprogrammed SimCells and mini-SimCells can eliminate target E. coli with high specificity and efficiency. Multi-dose reprogrammed mini-SimCell treatment led to a 103-fold selective reduction of targeted bacteria in mixed microbial communities, with minimal disruption to non-target bacteria. We demonstrate that reprogrammed mini-SimCells, engineered with nanobody targeting outer membrane protein OmpA of the clinically relevant multidrug resistant pathogen E. coli ST131, achieved elimination efficiencies over 97% at 24 and 48 hrs. This modularised plug-and-play antimicrobial platform provides a highly specific, efficient and adaptable solution for combating diverse AMR pathogens. Significance StatementAntimicrobial-resistant (AMR) bacteria cause millions of deaths worldwide annually, representing a critical global health challenge. In this study, we developed a novel therapeutic platform using two types of chromosome-free, non-replicating engineered bacterial cells: SimCells (1-2 {micro}m) and mini-SimCells (100-400 nm). These SimCells were engineered to selectively bind to targeted E. coli, facilitating precise delivery of toxic proteins via a Type VI secretion system (T6SS) and localised generation of hydrogen peroxide from aspirin. We demonstrate that mini-SimCells eliminated over 97% of a targeted AMR strain within 48 hours. Moreover, multiple-dose administration achieved a selective 103-fold reduction of targeted E. coli in mixed microbial communities. This modular plug-and-play platform offers an adaptable solution against diverse multi-drug-resistant pathogens.

synthetic biology↗

bioRxiv2025

Multi-omics analyses reveal the effect of DNA methylation on iridoid glycosides biosynthesis in Rehmannia glutinosa

Rehmannia glutinosa roots produce a group of lipophilic bioactive components known as iridoid glycosides. However, the molecular mechanisms by which DNA methylation regulates the biosynthesis of iridoid glycosides in R. glutinosa remain unknown. Herein, the development of R. glutinosa roots and the content of iridoid glycosides in the Wenxian region were significantly higher than those in Xinxiang. Low methylation level contributed to the accumulation of iridoid glycosides and the expression of related enzyme genes. Demethylation promoted both roots growth and development, as well as the accumulation of iridoid glycosides. Up-regulated RgALDH13, RgHDR1, RgG10H4, RgDXR1, RgG10H3, and RgUPD1, along with transcription factors (TFs), form the regulatory network for the biosynthesis of iridoid glycosides. Furthermore, the primary active region of the RgG10H4 promoter is located in the -164 bp region, where the RgMYB2 protein specifically binds to the TAACCA motif in the RgG10H4 promoter. Collectively, low levels of DNA methylation enhance the expression of core genes, followed by inducing the accumulation of iridoid glycosides, which suggests that RgMYB2-RgG10H4 plays a positive role in this process. These findings will contribute to a deeper understanding of the role of DNA methylation in the accumulation of iridoid glycosides. HighlightLow levels of DNA methylation contribute to the accumulation of iridoid glycosides and the expression of key enzyme genes in R. glutinosa.

molecular biology↗

bioRxiv2025

The Pathological Role and Therapeutic potential of ALDH2 in acrolein detoxification Following Spinal Cord Injury in Mice

Oxidative stress and lipid peroxidation-derived aldehydes, such as acrolein, play a central role in the pathology of spinal cord injury (SCI) and have emerged as promising therapeutic targets. Mitochondrial aldehyde dehydrogenase-2 (ALDH2) is a key oxidoreductase responsible for detoxifying reactive aldehydes. Pharmacological activation of ALDH2 using Alda-1, a selective agonist, has been shown to reduce aldehyde accumulation, alleviate inflammation, and enhance functional recovery in experimental SCI models. However, approximately 8% of the global population carries the ALDH2*2 mutation, which severely impairs this detoxification pathway. In this study, we used a transgenic ALDH2*2 mouse model to investigate the role of ALDH2 in SCI pathology. This model mimics the human ALDH2*2 condition, allowing us to examine the impact of impaired aldehyde clearance on acrolein accumulation and its pathological consequences. We modulated endogenous aldehyde detoxification through both genetic deficiency and pharmacological activation with Alda-1. Our results showed that ALDH2 deficiency led to significantly elevated acrolein levels, which were associated with increased microglial activation, cytokine storm, neuronal loss, demyelination, and tissue damage compared to wild-type (WT) mice. Treatment with Alda-1 enhanced ALDH2 activity and significantly reduced acrolein levels in both ALDH2*2 and WT mice from 2 to 28 days post-SCI. This was accompanied by reduced inflammation, improved preservation of myelin, and marked improvements in locomotor and sensory function, especially in ALDH2*2 mice. Notably, even beyond the traditionally ideal treatment window, Alda-1 treatment remained effective in promoting recovery, particularly in motor function and to a greater extent in ALDH2*2 mice. Our study comprehensively evaluated ALDH2s role in SCI by both genetically impairing and pharmacologically enhancing its activity, highlighting ALDH2 as a critical modulator of acrolein-mediated damage and suggesting its potential as a therapeutic target, especially for individuals with the ALDH2*2 mutation.

neuroscience↗

bioRxiv2025

Identification of High-Risk Cells in Single-Cell Spatially Resolved Transcriptomics Data Using Deep Transfer Learning

SummaryThe examination of high-risk cells and regions in tissue samples from spatially resolved transcriptomics platforms offers meaningful insights into specific disease processes. For existing methods, while cell types or clusters can be identified and associated with disease attributes, individual cells are unable to be associated in the same manner. MethodDiag-nostic Evidence GAuge of Single-cells and spatial transcriptomics (DEGAS), solves the above problem by employing latent representations of gene expression data and domain adaptation to transfer disease attributes from patients to individual cells from single-cell RNA sequencing datasets. In this research, we present and evaluate DEGASs versatility in adapting to data arising from various single-cell spatially resolved transcriptomics (scSRT) platforms. DEGAS successfully identified high-risk cells and regions in liver hepatocellular carcinoma and skin cutaneous melanoma, which were validated through known markers. Additionally, DEGAS was applied to our newly generated Type II Diabetes Xenium dataset revealing high-risk cells within the tissue samples. Availability and ImplementationThe DEGAS software can be accessed at https://github.com/tsteelejohnson91/DEGAS. For the updated smoothing functions and associated codes, visit https://github.com/dchatter04/DEGAS-Spatial-Smoothing. Sources for the datasets reviewed are detailed in their respective sections. A description of some datasets, along with extra tables and figures, is provided in the Supplementary Materials file. Our newly generated Xenium data for Type II Diabetes can be found at https://doi.org/10.7303/syn68699752.

bioinformatics↗

bioRxiv2024

Deep-learning-enabled generative prevalent mutation prediction through host-to-herd in silico virus evolution

Predicting the mutation prevalence trends of emerging viruses in the real world is an efficient means to update vaccines or drugs in advance. It is crucial to develop a computational method for the prediction of real-world prevalent SARS-CoV-2 mutations considering the impact of multiple selective pressures within and between hosts. Here, a deep-learning generative framework for real-world prevalent SARS-CoV-2 mutation prediction, named ViralForesight, is developed on top of protein language models and in silico virus evolution. Through the paradigm of host-to-herd in silico virus evolution, ViralForesight reproduced previous real-world prevalent SARS-CoV-2 mutations for multiple lineages with superior performance. More importantly, ViralForesight correctly predicted the future prevalent mutations that dominate the COVID-19 pandemic in the real world more than half a year in advance with in vitro experimental validation. Overall, ViralForesight demonstrates a proactive approach to the prevention of emerging viral infections, accelerating the process of discovering future prevalent mutations with the power of generative deep learning.

evolutionary biology↗

bioRxiv2024

Identification and genomic characterization of a novel bisegmented coronavirus in the lesser panda

Coronaviruses (CoVs) are enveloped positive-sense single-stranded RNA viruses and are renowned for their capacity to infect a diverse range of animals, including humans. In this study, we report the identification and characterization of a novel bisegmented coronavirus, designated LpCoV, from a dead lesser panda, which exhibited severe clinical manifestations and lesions in multiple organs. The LpCoV represents the first documented coronavirus with a unique bisegmented genome while maintaining the typical coronavirus morphology. One genomic segment encodes the ORF1ab polyprotein, while the other segment encodes the spike and nucleocapsid proteins, notably lacking the envelope (E) and membrane (M) genes. The pairwise patristic distances of the five concatenated domains in the replicase region (3CLpro, NiRAN, RdRP, ZBD, and HEL1) between LpCoV and -{delta} coronaviruses range from 1.19 to 1.70. Based on the classification criteria established by the International Committee on Taxonomy of Viruses (ICTV), LpCoV is proposed to constitute a new genus within the Coronaviridae family. An epidemiological investigation identified five LpCoV-like viruses in lesser pandas from two different provinces (Sichuan and Jiangsu) indicating the long-term circulation and expansion of bisegmented coronaviruses in wildlife. These findings highlight the imperative for comprehensive viral surveillance in wildlife, which is essential for understanding and mitigating the risk of animal diseases and zoonotic spillover.

microbiology↗

bioRxiv2024

The Association Between Prevotella copri and Advanced Fibrosis in the Progression of Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), driven by obesity and metabolic syndrome, is increasingly prevalent and a significant contributor to liver fibrosis, cirrhosis, and liver-related mortality. Emerging research implicates the gut microbiome as a critical player in MASLD progression, yet specific microbial drivers remain poorly understood. Here, we explore the role of Prevotella copri (P. copri) in MASLD progression through both human patient cohorts and a mouse model of diet-induced obesity. Using 16S rRNA sequencing, we identified elevated P. copri abundance in MASLD patients with advanced fibrosis, linked with significant shifts in microbial diversity and bacterial network connectivity. To investigate causality, experimental colonization of P. copri in mice on a high-fat diet worsened MASLD progression, with P. copri-colonized mice showing significant increases in hepatic steatosis, liver triglyceride accumulation, and body weight, independent of caloric intake. At the molecular level, P. copri colonization downregulated key lipid metabolism genes, such as Carnitine Palmitoyltransferase 1, Diacylglycerol Acyltransferase, and Adipose Triglyceride Lipase, and impaired tight intestinal junction integrity through the downregulation of cluadins, occludin, and zonula occludens-1. Collectively, our findings position P. copri as a possible driver of MASLD progression by promoting hepatic steatosis through lipid and triglyceride accumulation and fibrosis through decreased tight junction integrity. These insights suggest a promising therapeutic avenue to target specific microbial signatures like P. copri to curb MASLD progression and mitigate the associated risk of advanced fibrosis.

microbiology↗

bioRxiv2024

Microbial Differences Accurately Identifies Global SERT KO Phenotype in Mice

Altered serotonin signaling is a well-established contributor to depression, with the serotonin transporter gene (SERT) playing a critical role in regulating serotonin reuptake. Mice lacking SERT (SERT -/-) serve as a robust model for depression, exhibiting significant depressive-like behaviors compared to littermate wild-type (SERT +/+) controls. In this study, we aimed to determine the relationship between gut microbiota composition and depressive behaviors in SERT -/- mice. Behavioral assays, including the Forced Swim Test (FST) and Tail Suspension Test (TST), confirmed that SERT -/- mice exhibited significantly increased immobility times compared to SERT +/+ mice (FST: p = 0.004; TST: p = 0.080), consistent with a depressive phenotype. Utilizing littermate controls, shotgun metagenomic sequencing of fecal samples revealed significant differences in alpha diversity between the two groups of mice, as measured by the Shannon entropy index (p = 0.05). Additionally, our bacterial co-occurrence network analysis uncovered distinct structural differences in microbial interactions between SERT -/- and SERT +/+ mice (p = 0.001), suggesting shifts in microbiome stability and functionality between the groups. We created a microbial depression score utilizing the top five bacteria taxa that were differentially abundant between SERT -/- and SERT +/+ mice: Clostridium sp. MD294, Acetatifactor MGBC165152, Desulfovibrio MGBC129232, Oscillibacter MGBC161747, and Schaedlerella MGBC000001. This microbial depression score correlated strongly with immobility times in the FST (r = 0.705, p < 0.0006) and TST (r = 0.401, p < 0.09). A random forest classifier based on these taxa accurately distinguished SERT -/- from SERT +/+ mice (accuracy = 0.82). These findings suggest that gut microbial species composition is highly associated with depressive-like behaviors in SERT -/- mice, likely via alterations in serotonin signaling pathways, and may offer potential targets for microbiome-based interventions in depression.

microbiology↗

bioRxiv2024

Allo-Allo: Data-efficient prediction of allosteric sites

Allostery, a fundamental structural mechanism where ligand binding at a protein site affects protein function at another site, plays a crucial role in key drug-target proteins like GPCRs. Unfortunately, existing methods for predicting allosteric sites have limited performance- they are particularly constrained by scarce ground-truth experimental data. We introduce Allo-Allo, a data-efficient, sequence-based method that predicts allosteric sites by leveraging protein language models (PLMs). Honing in on ESM-2 attention heads that capture allosteric residue associations, Allo-Allo achieves a 67% higher AUPRC than state-of-the-art methods. Our innovative, data-efficient pipeline not only outperforms alternate, commonly-used PLM-based prediction architectures but also generalizes well. Notably, mutations in Allo-Allo-predicted sites show significant association with elevated disease risk scores from AlphaMissense, highlighting its translational potential. Beyond Allo-Allos biological and translational applicability, its architecture presents a powerful framework for other data-scarce problems in protein analysis.

bioinformatics↗

bioRxiv2024

Amidase and Lysozyme Dual Functions in TseP Reveal a New Family of Chimeric Effectors in the Type VI Secretion System

Peptidoglycan (PG) serves as an essential target for antimicrobial development. An overlooked reservoir of antimicrobials lies in the form of PG-hydrolyzing enzymes naturally produced for polymicrobial competition, particularly those associated with the type VI secretion system (T6SS). Here we report that a T6SS effector TseP, from Aeromonas dhakensis, represents a family of effectors with dual amidase-lysozyme activities. In vitro PG-digestion coupled with LC-MS analysis revealed the N-domains amidase activity, which is neutralized by either catalytic mutations or the presence of the immunity protein TsiP. The N-domain, but not the C-domain, of TseP is sufficient to restore T6SS secretion in T6SS-defective mutants, underscoring its critical structural role. Using pull-down and secretion assays, we showed that these two domains interact directly with a carrier protein VgrG2 and can be secreted separately. Homologs in Aeromonas hydrophila and Pseudomonas syringae exhibited analogous dual functions. Additionally, N- and C-domains display distinctive GC contents, suggesting an evolutionary fusion event. By altering the surface charge through structural-guided design, we engineered the TsePC4+ effector that successfully lyses otherwise resistant Bacillus subtilis cells, enabling the T6SS to inhibit B. subtilis in a contact-independent manner. This research uncovers TseP as a new family of bifunctional chimeric effectors targeting PG, offering a potential strategy to harness these proteins in the fight against antimicrobial resistance. Significance StatementAntimicrobial resistance urgently demands global interventions, and the bacteria cell wall remains a promising target. Our research introduces a novel family of bifunctional, cell-wall-damaging T6SS effectors. More importantly, we demonstrate an effective strategy to enable an otherwise ineffective enzyme to target both Gram-negative and Gram-positive bacteria. Our findings highlight a promising path forward using cell-wall-damaging effectors, a largely untapped resource, in the fight against antimicrobial resistance.

microbiology↗