Biology subjects

Zheng, J.

Publications and source records attributed to Zheng, J..

At least 109 records · Page 6Linked to original sources

bioRxiv2025

An invariant schema emerges within a neural network during hierarchical learning of visual boundaries

Neural circuits must balance plasticity and stability to enable continual learning without catastrophic forgetting, a pervasive feature of artificial neural networks trained using end-to-end learning (e.g. backpropagation). Here, we apply an alternative, hierarchical learning algorithm to the cognitive task of boundary detection in video clips. In contrast to backpropagation, hierarchical training converges to a network executing a fixed schema and generates firing statistics consistent with single-neuron recordings from human subjects performing the same task. The hierarchically trained networks schema circuit remains invariant following training on sparse data, with additional data serving to refine the upstream representation.

neuroscience↗

bioRxiv2025

DNA repair functions are essential for bacterial stress defense but render antibiotic tolerant sub-populations susceptible to ciprofloxacin and gentamicin upon prolonged treatment

The unresponsiveness of bacterial tolerant subpopulations to antibiotics has been attributed to physiological dormancy triggered by environmental stresses. In this work, we showed that protein and DNA synthesis activities in tolerant subpopulations that formed during nutrient starvation remained at a high level and only dropped gradually during the course of six days-starvation. Interestingly, upon decline of these activities, the tolerant subpopulations became susceptible to antibiotics that target protein and DNA synthesis, which was found to be required to support DNA repair functions essential for prolonged survival of the tolerant subpopulation. The increasing susceptibility of the bacterial tolerant subpopulation to antibiotics was also due to diminishing energy production, antioxidant defense and efflux functions, which resulted in weakening defense and further inhibition of synthesis and functions of DNA repair and other defense proteins. These findings confirm that bacterial tolerant subpopulations remain physiological active, and open new opportunities for combating bacterial tolerance with existing antibiotics.

microbiology↗

bioRxiv2025

Differential endopeptidase requirements during adaptation to changing growth conditions in Vibrio cholerae

The bacterial cell wall is a covalently linked meshwork of peptidoglycan (PG) that establishes cell shape and prevents osmotic lysis. This structure must be flexible enough to accommodate transenvelope protein complexes, but strong enough to withstand high intracellular pressure. In order to elongate and divide, cells must remodel the cell wall through the concerted action of PG synthesis and degradation. Endopeptidases, a class of PG degrading enzymes, facilitate cell growth by hydrolyzing PG crosslinks. Vibrio cholerae encodes several functionally redundant endopeptidases, two of which are nearly identical: ShyA and ShyC. To investigate differential roles of these enzymes, we assessed growth and morphology of ShyA and ShyC mutants. We found that ShyA, but not ShyC, is required for normal adaptation to low osmolarity medium. Cells lacking ShyA exhibited longer lag phase and aberrant morphology during adaptation, and reduced survival in the presence of a beta-lactam antibiotic. Lastly, our experiments revealed that cells lacking ShyAs LysM domain exhibited more severe defects than cells lacking ShyA altogether, implicating the LysM domain in proper regulation of ShyA activity.

microbiology↗

bioRxiv2025

RAS-PI3K Pathway in CAFs Shapes Physicochemical Properties of Tumor ECM and restrains Tumor progression

Cancer-associated fibroblasts display extensive functional plasticity, yet the signaling mechanisms that stabilize distinct CAF states remain poorly understood. Here, we identify stromal RAS-PI3K signaling as a key regulator of myofibroblastic CAF identity and matrix competence in lung cancer. Genetic disruption of the RAS-PI3K interaction in fibroblasts preserved upstream responsiveness to activating cues but impaired cytoskeletal remodeling, contractile execution and acquisition of a matrix-remodeling CAF program. As a result, RAS-PI3K-deficient CAFs generated extracellular matrices with defective collagen and fibronectin organization, reduced stiffness, altered microstructural properties and broad compositional remodeling of the matrisome, including changes in ECM glycoproteins and glycosylation-associated enzymes. These altered matrices failed to efficiently provide directional, adhesive and proliferative cues to tumor cells, attenuated EMT-associated programs and increased sensitivity to cisplatin plus pemetrexed. In vivo, fibroblast-specific RAS-PI3K disruption reduced tumor burden, decreased tumor cell proliferation, prolonged survival and improved chemotherapy response. Loss of RAS-PI3K signaling did not simply suppress CAF activation, but redirected CAFs toward a STAT3/NF-{kappa}B-linked immunomodulatory state associated with IL6, CXCL12 and PDGFR induction. Functionally, this altered stromal state promoted iNOS-associated macrophage features and was accompanied in vivo by reduced macrophage accumulation and increased CD8 T cell infiltration. These findings establish RAS-PI3K signaling as a stromal state-control mechanism that couples myofibroblastic matrix competence to tumor-supportive microenvironmental function while restraining alternative immunomodulatory CAF programs.

cancer biology↗

bioRxiv2025

Unveiling the Evolution of Antimicrobial Peptides in Gut Microbes via Foundation Model-Powered Framework

Antimicrobial resistance poses a growing threat to public health, emphasizing the urgent need for novel therapeutic strategies. Antimicrobial peptides (AMPs), short peptide sequences with diverse mechanisms of action, offer a promising alternative due to their broad-spectrum activity against pathogens. Recent advances in protein language models (PLMs) have revolutionized protein structure prediction and functional annotation, highlighting their potential for AMP discovery and therapeutic development. In this context, we present AMP-SEMiner (Antimicrobial Peptide Structural Evolution Miner), an AI-driven framework designed to identify AMPs from metagenome-assembled genomes (MAGs). By integrating PLMs, structural clustering and evolutionary analysis into the framework, AMP-SEMiner can identify AMPs encoded by small open reading frames (smORFs) and encrypted peptides (EPs), significantly expanding the discovery space. Using this approach, we identified 1,670,600 AMP candidates from diverse habitats. Experimental validation of 29 candidates revealed antimicrobial activity in 18, with 13 surpassing antibiotics in effectiveness. Further analysis of AMPs from human gut microbiomes demonstrated both conserved and adaptive evolutionary strategies, ensuring their functional efficacy in the dynamic gut environment. These findings position AMP-SEMiner as a powerful tool for the discovery and characterization of novel AMPs, with significant potential to drive the development of new antimicrobial therapies.

microbiology↗

bioRxiv2025

Genomic feature of filled regions of telomere-to-telomere genomes in five model species

T2T genome is a telomere-to-telomere high-quality genome with exceptional accuracy, continuity and integrity. It significantly filled some gaps of chromosome. However, the genomic features unique to the filled regions assembled in the T2T genome across species remain unclear. Here, we collected and compared T2T genomes with their older version from human (Homo sapiens), animal (Mus musculus), and plants (Arabidopsis thaliana, Musa acuminata, and Fragaria vesca). We explored the newly filled regions generated by the T2T genome in comparison to the old one, and focused on: (1) the comparison of their locations, (2) the distribution of genomic features, and (3) gene annotation and gene function for filled regions. Research indicated that the filled regions of the T2T genome ordinarily appear in the centromere and telomere regions, contain a great number of repetitive sequences. The T2T genome revealed the identification of a certain number of newly annotated genes, alongside significant variations in common annotated genes. Interestingly, the genomic features of filled regions exhibit distinct patterns between plants and human/animal. T2T genomes feature analysis serves as a crucial resource for studying pattern characteristics across diverse species and advancing the in-depth development of genomics.

genomics↗

bioRxiv2024

Sensory expectations shape neural population dynamics in motor circuits

The neural basis of movement preparation has been extensively studied during self-initiated actions where motor cortical activity during preparation shows a lawful relationship to the parameters of the subsequent action1,2. However, movements are regularly triggered and constantly corrected based on sensory inputs caused by disturbances to the body or environment. Since such disturbances are often predictable and since preparing for disturbances would make movements better, we hypothesized that expectations about sensory inputs also influence preparatory activity in motor circuits. Here we show that when humans and monkeys are probabilistically cued about the direction of a future mechanical perturbation, they incorporate sensory expectations into their movement preparation and improve their corrective responses. Using high-density neural recordings, we establish that sensory expectations are widespread across the brain, including the motor cortical areas involved in preparing self-initiated actions. The geometry of these preparatory signals in the neural population state is simple, scaling directly with the probability of each perturbation direction. After perturbation onset, a condition-independent perturbation signal shifts the neural state leading to rapid responses that initially reflect sensory expectations. Based on neural networks coupled to a biomechanical model of the arm3, we show that this neural geometry emerges through training, but only when the incoming sensory information indicating perturbation direction coincides with - or is preceded by - a condition-independent signal indicating that a perturbation has occurred. Thus, motor circuit dynamics are shaped by future sensory inputs, providing clear empirical support for the idea that movement is governed by the sophisticated manipulation of sensory feedback4.

neuroscience↗

bioRxiv2024

Synergistic activation of the human phosphate exporter XPR1 by KIDINS220 and inositol pyrophosphate

Inorganic phosphate (Pi) is fundamental to life, and its intracellular concentration must be tightly regulated to prevent toxicity. XPR1, the only known phosphate exporter, plays a crucial role in maintaining this delicate balance. However, the mechanisms underlying the function and regulation of XPR1 remain elusive until now. Here we present cryo-electron microscopy structures of the human XPR1-KIDINS220 complex in both substrate-free closed states and substrate-bound outward-open states, as well as the structure of an XPR1 mutant alone in a substrate-bound inward-facing state. In the presence of inositol hexaphosphate (InsP6) and phosphate, the XPR1-KIDINS220 complex adopts an outward-open conformation. InsP6 binds both the SPX domain and the peripheral juxtamembrane regions of XPR1, indicative of an active phosphate-export state. Conversely, in the absence of either phosphate or InsP6, the complex assumes a closed state, where the extracellular half of transmembrane 9 occupies the outward cavity, and a C-terminal plug-in loop blocks the intracellular cavity. Notably, XPR1 without KIDINS220 adopts a closed state despite the presence of phosphate and InsP6. The functional mutagenesis experiments further demonstrate that InsP6, whose concentrations fluctuate in response to Pi availability, functions synergistically with KIDINS220 to regulate the phosphate export activity of XPR1. These findings not only elucidate the intricate mechanisms of cellular phosphate regulation but also hold promise for the development of targeted therapies for ovarian cancer, where XPR1 plays a significant role.

biophysics↗

bioRxiv2024

Base-modified nucleotides mediate immune signaling in bacteria

Signaling from pathogen sensing to effector activation is a fundamental principle of cellular immunity. While cyclic (oligo)nucleotides have emerged as key signaling molecules, the existence of other messengers remains largely unexplored. Here, we reveal a bacterial anti-phage system that mediates immune signaling through nucleobase modification. Immunity is triggered by phage nucleotide kinases, which, combined with the system-encoded adenosine deaminase, produce deoxyinosine 5-triphosphate (dITP) as immune messengers. The dITP signal activates downstream effector to mediate cellular NAD+ depletion, resulting in population-level defense through the death of infected cells. To counteract immune signaling, phages deploy specialized enzymes that deplete cellular dAMP, the precursor of dITP messengers. Our findings uncover a nucleobase modification-based anti-phage signaling pathway, establishing noncanonical nucleotides as a new type of immune messengers in bacteria.

microbiology↗

bioRxiv2024

Assessment of DNA methylation from a single genomic region of ELOV2 is sufficient to predict chronological age

Estimation of chronological age is particularly informative in forensic contexts. Assessment of DNA methylation status allows for the prediction of age, though the accuracy and ease of manipulation may vary across different models. In this study, we started with a carefully designed discovery cohort recruiting more elderly subjects than other age categories, to diminish the effect of epigenetic drifting. We analyzed DNA methylation from a single genomic region of ELOV2, which was sufficient to construct an age-prediction model comprising 15 CpG sites. This model is further validated by an independent cohort as well as a multi-center test using trace dried bloodstains. The nature of our analytical pipeline, when combined the assessment of a single genomic locus with high-throughput sequencing, can easily be scaled up with low cost. Taken together, we propose a new age-prediction model featuring accuracy, ease of manipulation, high-throughput, and low cost. This model can be readily applied in both classic and newly emergent forensic contexts that require age estimation.

genetics↗

bioRxiv2024

Inbreeding and demography interact to impact population recovery from bottlenecks

Biodiversity loss driven by climate change and human activities poses a critical global challenge. Population restoration and reintroduction programs are essential for mitigating this threat, yet their outcomes are often unpredictable due to poorly understood success factors. The conservation program of the crested ibis (Nipponia nippon) marks a successful example where the population rose from seven survivors to over 9,000 in the past four decades. To learn whether this successful restoration was due to chance or largely repeatable, we developed an individual-based model that simulates the restoration process by incorporating life-history parameters from empirical data. Our simulation results closely mirror empirical findings, including the time taken to reach the current population size and population-level inbreeding coefficients. We further analyzed the model to compare the effectiveness of two reintroduction strategies and analyzed how inbreeding depression interacts with demography to influence the chance of recovery from bottlenecks. The reintroduction simulations reveal that the firework approach (one-source translocations) outperforms the stepping-stone (serial translocations) approach in restoration effectiveness. Our simulations over broad demographic parameters demonstrate that the net effect of inbreeding varies with species-specific demography, and highlight the importance of considering this interaction when interpreting conservation outcomes and designing future reintroduction programs.

ecology↗

bioRxiv2024

Protein Language Model Identifies Disordered, Conserved Motifs Driving Phase Separation

Intrinsically disordered regions (IDRs) play a critical role in phase separation and are essential for the formation of membraneless organelles (MLOs). Mutations within IDRs can disrupt their multivalent interaction networks, altering phase behavior and contributing to various diseases. Therefore, examining the evolutionary constraints of IDRs provides valuable insights into the relationship between protein sequences and phase separation. In this study, we utilized the ESM2 protein language model to map the residue-level mutational tolerance landscapes landscape of IDRs. Our findings reveal that IDRs, particularly those actively participating in phase separation, contain conserved amino acids. This conservation is evident through mutational constraints predicted by ESM2 and supported by direct analyses of multiple sequence alignments. These conserved, disordered amino acids include residues traditionally identified as "stickers" as well as "spacers" and frequently form continuous sequence motifs. The strong conservation, combined with their potential role in phase separation, suggests that these motifs may act as functional units under evolutionary selection to support stable MLO formation. Our findings underscore the insights into phase separations molecular grammar made possible through evolutionary analysis enabled by protein language models.

biophysics↗

bioRxiv2024

VaxLLM: Leveraging Fine-tuned Large Language Model for automated annotation of Brucella Vaccines

BackgroundVaccines play a vital role in enhancing immune defense and preventing the hosts against a wide range of diseases. However, research relating to vaccine annotation remains a labor-intensive task due to the ever-increasing volume of scientific literature. This study explores the application of Large Language Models (LLMs) to automate the classification and annotation of scientific literature on vaccines as exemplified on Brucella vaccines. ResultsWe developed an automatic pipeline to automatically perform the classification and annotation of Brucella vaccine-related articles, using abstract and title. The pipeline includes VaxLLM (Vaccine Large Language Model), which is a fine-tuned Llama 3 model. VaxLLM systematically classifies articles by identifying the presence of vaccine formulations and extracts the key information about vaccines, including vaccine antigen, vaccine formulation, vaccine platform, host species used as animal models, and experiments used to investigate the vaccine. The model demonstrated high performance in classification (Precision: 0.90, Recall: 1.0, F1-Score: 0.95) and annotation accuracy (97.9%), significantly outperforming a corresponding non-fine-tuned Llama 3 model. The outputs from VaxLLM are presented in a structured format to facilitate the integration into databases such as the VIOLIN vaccine knowledgebase. To further enhance the accuracy and depth of the Brucella vaccine data annotations, the pipeline also incorporates PubTator, enabling cross comparison with VaxLLM annotations and supporting downstream analyses like gene enrichment. ConclusionVaxLLM rapidly and accurately extracted detailed itemized vaccine information from publications, significantly outperforming traditional annotation methods in both speed and precision. VaxLLM also shows great potential in automating knowledge extraction in the domain of vaccine research. AvailabilityAll data is available at https://github.com/xingxianli/VaxLLM, and the model was also uploaded to HuggingFace (https://huggingface.co/Xingxian123/VaxLLM).

bioinformatics↗

bioRxiv2024

Interlaboratory comparison of standardised metabolomics and lipidomics analyses in human and rodent blood using the MxP(R) Quant 500 kit

Metabolomics and lipidomics are pivotal in understanding phenotypic variations beyond genomics. However, quantification and comparability of mass spectrometry (MS)-derived data are challenging. Standardised assays can enhance data comparability, enabling applications in multi-center epidemiological and clinical studies. Here we evaluated the performance and reproducibility of the MxP(R) Quant 500 kit across 14 laboratories. The kit allows quantification of 634 different metabolites from 26 compound classes using triple quadrupole MS. Each laboratory analysed twelve samples, including human plasma and serum, lipaemic plasma, NIST SRM 1950, and mouse and rat plasma, in triplicates. 505 out of the 634 metabolites were measurable above the limit of detection in all laboratories, while eight metabolites were undetectable in our study. Out of the 505 metabolites, 412 were observed in both human and rodent samples. Overall, the kit exhibited high reproducibility with a median coefficient of variation (CV) of 14.3 %. CVs in NIST SRM 1950 reference plasma were below 25 % and 10 % for 494 and 138 metabolites, respectively. To facilitate further inspection of reproducibility for any compound, we provide detailed results from the in-depth evaluation of reproducibility across concentration ranges using Deming regression. Interlaboratory reproducibility was similar across sample types, with some species-, matrix-, and phenotype-specific differences due to variations in concentration ranges. Comparisons with previous studies on the performance of MS-based kits (including the AbsoluteIDQ p180 and the Lipidyzer) revealed good concordance of reproducibility results and measured absolute concentrations in NIST SRM 1950 for most metabolites, making the MxP(R) Quant 500 kit a relevant tool to apply metabolomics and lipidomics in multi-center studies.

biochemistry↗

bioRxiv2024

Neuronal Detection Triggers Systemic Digestive Shutdown in Response to Adverse Food Sources

The ability to sense and adapt to adverse food conditions is essential for survival across species, but the detailed mechanisms of neuron-digestive crosstalk in food sensing and adaptation remain poorly understood. This study identifies a novel mechanism by which animals detect unfavorable food sources through neurons and initiate a systemic response to shut down digestion, thus safeguarding against potential harm. Specifically, we demonstrate that NSY-1, expressed in AWC neurons, detects Staphylococcus saprophyticus (SS) as an unfavorable food source, prompting the animal to avoid and halt digestion of SS. Upon detection, the animals activate the AWCOFF neural circuit, leading to a systemic digestive shutdown, which is mediated by NSY-1-dependent STR-130. Additionally, NSY-1 mutation triggers the production of insulin peptides, including INS-23, which interact with the DAF-2 receptor to modulate SS digestion and affects the expression of intestinal BCF-1. These findings uncover a crucial survival strategy through neuron-digestive crosstalk, where the NSY-1 pathway in AWC neurons orchestrates food evaluation and initiates digestive shutdown to adapt effectively to harmful food sources.

physiology↗

bioRxiv2024

Emergence of alternative offspring care patterns from the evolution of parental negotiation strategies

The evolution of parental cooperation is challenging to explain because caring for offspring is costly, and parents face an evolutionary conflict of interests over how much care each should contribute. Evolutionary game theory suggests that this conflict may be resolved through parental negotiation, where the parents make their care level dependent on the care provided by their partner. However, mathematical negotiation models typically predict a low level of parental cooperation. As these models are not dynamically explicit and tend to neglect stochasticity, we here investigate the evolution of parental negotiation strategies by means of individual-based simulations. Our results differ markedly from earlier analytical predictions. Parental negotiation strategies readily evolve, but replicate simulations result in four alternative care patterns: uniparental care, sex-biased care and egalitarian biparental care with constant or oscillatory care levels. Hence, pronounced sex differences in parental care can evolve even in the absence of sexual selection and uncertainty of paternity. Effective parental cooperation is the most frequent outcome, but in contrast to the earlier models, it is not based on parental compensation but on a tit-for-tat negotiation strategy. Actually, compensation destabilises cooperation and leads to less effective outcomes where one parental sex exploits the other one.

evolutionary biology↗

bioRxiv2024

Neuron-astrocyte Coupling in Lateral Habenula Mediates Depressive-like Behaviors

The lateral habenular (LHb) neurons and astrocytes have been strongly implicated in depression etiology but it was not clear how the two dynamically interact during depression onset. Here, using multi-brain-region calcium photometry recording in freely-moving mice, we discover that stress induces a unique, bimodal neuronal response and a most rapid astrocytic response in the LHb. LHb astrocytic calcium requires the 1A-adrenergic receptor, and depends on a recurrent neural network between the LHb and locus coeruleus (LC). Through the gliotransmitter glutamate and ATP/Adenosine, LHb astrocytes mediate the second-wave activation of local LHb neurons as well as release of norepinephrine (NE). Activation or inhibition LHb astrocytic calcium signaling facilitates or prevents stress-induced depressive-like behaviors respectively. These results identify a stress-induced positive feedback loop in the LHb-LC axis, with astrocytes being a critical signaling relay. The identification of this prominent neuron-glia interaction may shed light on stress management and depression prevention.

neuroscience↗

bioRxiv2024

Deficiency of Hv1 Proton Channel Enhances Macrophage Antigen Presentation and Anti-Tumor Responses in Glioma

In the tumor microenvironment of glioblastoma, myeloid cells act as a double-edged sword--they are a major cellular component modulating the immune response while presenting a potential therapeutic target. Our study highlights the voltage-gated proton channel Hv1, predominantly expressed in myeloid cells, as a crucial regulator of their physiological functions. We discovered a strong correlation between increased Hv1 expression and poor prognosis in glioblastoma patients. Depleting Hv1 significantly extended survival in a mouse model of glioma. Employing multiple novel transgenic mouse lines, we demonstrated that Hv1 is upregulated in response to tumor presence, with glioma-associated macrophages as the principal contributors. Specifically, we identified that Hv1 in infiltrating macrophages as the major driver of survival phenotype differences. Through a combination of in vivo two-photon imaging, spectral flow cytometry, and spatial transcriptomic sequencing, we found that Hv1 depletion leads to reduced macrophage infiltration and enhanced antigen presentation, ultimately fostering a stronger adaptive immune response. These findings establish the Hv1 channel as a crucial new immune regulator within the brain tumor milieu, offering a promising target for reprogramming macrophage function to combat glioblastoma.

neuroscience↗