Biology subjects

Chen, S.

Publications and source records attributed to Chen, S..

At least 451 records · Page 25Linked to original sources

bioRxiv2023

Integrated-omics profiling unveils the disparities of host defense to ECM scaffolds during wound healing in aged individuals.

Extracellular matrix (ECM) scaffold membranes have exhibited promising potential to better the outcomes of wound healing by creating a regenerative microenvironment around. However, when compared to the application in younger individuals, the performance of the same scaffold membrane in promoting re-epithelialization and collagen deposition was observed dissatisfying in aged mice. To comprehensively elucidate the mechanisms underlying this age-related disparity, we conducted an integrated analysis, combing single-cell RNA sequencing (scRNA-Seq) with spatial transcriptomics, to explore the complex cellular niches surrounding the ECM scaffolds. Through intergroup comparative analysis and cell-cell communication, we identified and characterized the senescent SPP1+ macrophages may impede the activation of the type L immune response, thus inhibiting the repair ability of epidermal cells and fibroblasts around the ECM scaffolds. These findings contribute to a deeper understanding of biomaterial applications in varied physiological contexts, thereby paving the way for the development of precision-based biomaterials tailored specifically for aged individuals in future therapeutic strategies.

immunology↗

bioRxiv2023

The tumour suppressor Fat1 is dispensable for normal murine haematopoiesis

Loss and overexpression of FAT1 occurs among different cancers with these divergent states equated with tumor suppressor and oncogene activity, respectively. Regarding the latter, FAT1 is highly expressed in a high proportion of human acute leukemias relative to normal blood cells, with evidence pointing to an oncogenic role. We hypothesized that this occurrence represents legacy expression of FAT1 in undefined hematopoietic precursor subsets that is sustained following transformation, predicating a role for FAT1 during normal hematopoiesis. We explored this concept by using the Vavi-Cre strain to construct conditional knockout (cKO) mice where Fat1 expression was deleted at the hemopoietic stem cell stage. Extensive analysis of precursor and mature blood populations using multi-panel flow cytometry revealed no ostensible differences between Fat1 cKO mice and normal littermates. Further functional comparisons involving colony forming unit and competitive bone marrow transplantation assays support the conclusion that Fat1 is dispensable for normal murine haematopoiesis.

cancer biology↗

bioRxiv2023

scPharm: identifying pharmacological subpopulations of single cells for precision medicine in cancers

Intratumour heterogeneity is a major challenge that limits the effectiveness of anticancer therapies, thus compromising treatment outcomes. Single-cell RNA sequencing (scRNA-seq) technology offers a means to capture gene expression profiles at a single-cell resolution, while drug perturbation experiments yield valuable pharmacological data at the bulk cell level. Here, we introduce "scPharm", a computational framework to integrate large-scale pharmacogenomics profiles with scRNA-seq data, for identifying pharmacological subpopulations within a tumour and prioritizing tailored drugs. scPharm assesses the distribution of the identity genes of single cell (Cell-ID) within drug response-determined gene list, which is accomplished using the normalized enrichment score (NES) obtained from Gene Set Enrichment Analysis (GSEA) as the statistic. One key strength of scPharm is rooted in the robust positive correlation between NES statistics and drug response values at single-cell resolution. scPharm successfully identifies sensitive subpopulations in ER-positive and HER2-positive human breast cancer tissues, discovers dynamic changes in resistant subpopulation of human PC9 cells treated with Erlotinib, and expands its prediction capabilities to a mouse model. By a thoroughly comparative evaluation with other single-cell prediction tools, scPharm presents the superior predictive performance and computational efficiency. Furthermore, scPharm offers a unique feature by predicting combination strategies, gauging compensation effects or booster effects between two drugs through the Set covering method, as well as evaluating drug toxicity on healthy cells within the tumour microenvironment. Together, scPharm provides a novel approach to uncover therapeutic heterogeneity within tumours at single-cell resolution and facilitates precision medicine in cancers.

bioinformatics↗

bioRxiv2023

High-resolution ultrastructure and morphology of marine ammonia-oxidizing archaea Nitrosopumilus maritimus SCM1 revealed by Cryo-ET and STEM-EDS

Nitrososphaerota, formerly known as Thaumarchaeota, constitute a diverse and widespread group of ammonia-oxidizing archaea (AOA) inhabiting ubiquitously in marine and terrestrial environments, playing a pivotal role in global nitrogen cycling. Despite their significance in Earths ecosystems, the cellular organization of AOA remains largely unexplored, leading to a significant question unanswered of how the machinery of these organisms underpins metabolic functions. In this study, we combined chromatic-aberration-corrected cryo-electron tomography (cryo-ET), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDS) to unveil the cellular organization and elemental composition of Nitrosopumilus maritimus SCM1, a representative member of marine Nitrososphaerota. Our tomograms show the native ultrastructural morphology of SCM1 and one to several dense storage granules in the cytoplasm. STEM-EDS analysis identifies two types of storage granules in which one type is possibly composed of polyphosphate, while the other type is polyhydroxyalkanoate. Collectively, these findings provide visual evidence for the resilience of AOA in the vast oligotrophic marine environment.

microbiology↗

bioRxiv2023

Structure-Aware Dual-Target Drug Design through Collaborative Learning of Pharmacophore Combination and Molecular Simulation

Dual-target drug design has gained significant attention in the treatment of complex diseases, such as cancers and autoimmune disorders. A widely employed design strategy is combining pharmacophores to incorporate the knowledge of structure-activity relationships of both targets. Unfortunately, it often struggles with long and expensive trial and error, because protein pockets of two targets impose complex structural constraints on the pharmacophore combination. In this study, we propose AIxFuse, a structure-aware dual-target drug design method that learns pharmacophore fusion patterns to satisfy the dual-target structural constraints simulated by molecular docking. We utilize two self-play reinforcement learning (RL) agents to learn pharmacophore selection and fusion by comprehensive feedback including dual-target molecular docking scores. Collaboratively, the molecular docking scores are learned by active learning (AL). Through collaborative RL and AL, AIxFuse learns to generate molecules with multiple desired properties. AIxFuse is shown to outperform state-of-the-art methods in generating dual-target drugs against glycogen synthase kinase-3 beta (GSK3{beta}) and c-Jun N-terminal kinase 3 (JNK3). When applied to another task against retinoic acid receptor-related orphan receptor{gamma} -t (ROR{gamma}t) and dihydroorotate dehydrogenase (DHODH), AIxFuse exhibits consistent performance while compared methods suffer performance drops, leading to a 5 times outperformance in success rate. Docking studies demonstrate that AIxFuse can generate molecules concurrently satisfying the binding mode required by both targets. Further free energy perturbation calculation indicates that the generated candidates have promising binding free energies against both targets. Significance StatementComplex diseases like cancers and autoimmune disorders are mostly caused by multiple genes. Designing dual-target drugs against two target proteins simultaneously can achieve synergistic effects and alleviate drug resistance. In this study, we present AIxFuse, which to our knowledge is the first structure-aware dual-target drug design method that learns pharmacophore fusion patterns to satisfy the dual-target structural constraints simulated by molecular docking. AIxFuse exhibits superior performance to previous state-of-the-art methods on comprehensive benchmarks. By generating diverse drug candidates with promising dualtarget binding free energies and other desired properties, AIxFuse holds promising prospects for accelerating the development of novel dual-target drugs for long-term therapeutic of complex diseases.

pharmacology and toxicology↗

bioRxiv2023

INHBA/Activin A promotes tumor growth and induces resistance to anti-PD-L1 therapy by suppressing IFN-γ signaling

Inhibin beta A (INHBA) and its homodimer activin A have pleiotropic effects on modulation of immune responses and tumor progression, respectively, but it remains uncertain whether tumors may release activin A to regulate anti-tumor immunity. As evidenced by our RNA-Seq and in vitro results, the interferon-{gamma} (IFN-{gamma}) signaling pathway was significantly down-regulated by tumor intrinsic activin A. Tumor INHBA deficiency led to lower expression of PD-L1 induced by IFN-{gamma}, resulting in poor responsiveness to anti-PD-L1 therapy. On the other hand, decreased secretion of IFN-{gamma}-stimulated chemokines, including C-X-C motif chemokine 9 (CXCL9) and 10 (CXCL10), impaired the infiltration of effector T cells into the tumor microenvironment. Furthermore, the activin A-specific antibody garetosmab improved anti-tumor immunity and its combination with the anti-PD-L1 antibody atezolizumab showed a superior therapeutic effect to monotherapy. Our findings reveal that INHBA/activin A is involved in anti-tumor immunity by inhibiting the IFN-{gamma} signaling pathway and considered to be a potential target to overcome anti-PD-L1 resistance in clinical cancer treatment.

immunology↗

bioRxiv2023

Rapid, concerted switching of the neural code in inferotemporal cortex

A fundamental paradigm in neuroscience is the concept of neural coding through tuning functions1. According to this idea, neurons encode stimuli through fixed mappings of stimulus features to firing rates. Here, we report that the tuning of visual neurons can rapidly and coherently change across a population to attend to a whole and its parts. We set out to investigate a longstanding debate concerning whether inferotemporal (IT) cortex uses a specialized code for representing specific types of objects or whether it uses a general code that applies to any object. We found that face cells in macaque IT cortex initially adopted a general code optimized for face detection. But following a rapid, concerted population event lasting < 20 ms, the neural code transformed into a face-specific one with two striking properties: (i) response gradients to principal detection-related dimensions reversed direction, and (ii) new tuning developed to multiple higher feature space dimensions supporting fine face discrimination. These dynamics were face specific and did not occur in response to objects. Overall, these results show that, for faces, face cells shift from detection to discrimination by switching from an object-general code to a face-specific code. More broadly, our results suggest a novel mechanism for neural representation: concerted, stimulus-dependent switching of the neural code used by a cortical area.

neuroscience↗

bioRxiv2023

Chromosome-level scaffolding of haplotype-resolved assemblies using Hi-C data without reference genomes

Scaffolding is crucial for constructing most chromosome-level genomes. The high-throughput chromatin conformation capture (Hi-C) technology has become the primary scaffolding strategy due to its convenience and cost-effectiveness. As sequencing technologies and assembly algorithms advance, constructing haplotype-resolved genomes is increasingly preferred because haplotypes can provide additional genetic information on allelic and non-allelic variations. ALLHiC is a widely used allele-aware scaffolding tool designed for this purpose. However, its dependence on chromosome-level reference genomes and a higher chromosome misassignment rate still impede the unraveling of haplotype-resolved genomes. In this paper, we present HapHiC, a reference-independent allele-aware scaffolding tool with superior performance on chromosome assignment as well as contig ordering and orientation. Additionally, we provide new insights into the challenges in allele-aware scaffolding by conducting comprehensive analyses on various adverse factors. Finally, with the help of HapHiC, we constructed the haplotype-resolved allotriploid genome for Miscanthus x giganteus, an important lignocellulosic bioenergy crop. HapHiC is available at https://github.com/zengxiaofei/HapHiC.

bioinformatics↗

bioRxiv2023

Paternal genomic resources from the YanHuang cohort suggested a Weakly-Differentiated Multi-source Admixture model for the formation of Hans founding ancestral lineages

The large-scale human genome revolution and rapidly advanced statistical innovation have updated our understanding of the fine-scale and complex genetic structure, the entire landscape of genetic diversity and the evolutionary trajectories of spatiotemporally different ancients and ethnolinguistically diverse modern populations. Recent ancient DNA research provided a detailed and complex admixture picture of ancient Europeans but limited insights into East Asians as the few available genomes. Y-chromosome variations in the male-specific regions, served as molecular archaeological tool, have unique evolutionary features that can be utilized to reconstruct the origin and subsequent interaction of ancient East Asian paternal lineages. We launched the YanHuang cohort using our designed highest-resolution capture sequencing panel to explore the detailed evolutionary trajectory of the Han Chinese, one of the largest ethnic groups in the world. We reported one of the largest uniparental genomic resources and observed multiple founding paternal lineages dominant in ancient western Eurasian, Siberian and East Asian participating in the formation of the gene pool of the Han Chinese. We identified fine-scale paternal genetic structure correlated with different patterns of ancient population interaction and geographical mountain barriers (Qinling-Huaihe line and Nanling Mountains), suggesting isolation-enhanced and admixture-introduced genetic differentiation enhanced the complexity of the Han Chinese genomic diversity. We observed a strong direct correlation between the frequency of multiple founding lineages of the Han Chinese and the proportion of subsistence-related ancestry sources related to western pastoralists, Holocene Mongolian Plateau people and ancient East Asians, reflecting the ancient migration events contributed to our identified patterns of Chinese paternal genomic diversity. We finally provided one novel and the most plausible admixture-by-admixture model, the Weakly-Differentiated Multi-Source Admixture model, as the major genetic mechanism to illuminate our observed pattern of complex interactions of multiple ancestral sources and landscape of the Han Chinese paternal genetic diversity. Generally, we presented one large-scale uniparental genomic resource from the YanHuang cohort, portrayed one novel admixture formation model and presented the entire genomic landscape with multiple ancestral sources related to ancient herders, hunter-gatherers and farmers who participated in the ancestral formation of the Han Chinese.

evolutionary biology↗

bioRxiv2023

Amalga: Designable Protein Backbone Generation with Folding and Inverse Folding Guidance

Recent advances in deep learning enable new approaches to protein design through inverse folding and backbone generation. However, backbone generators may produce structures that inverse folding struggles to identify sequences for, indicating designability issues. We propose Amalga, an inference-time technique that enhances designability of backbone generators. Amalga leverages folding and inverse folding models to guide backbone generation towards more designable conformations by incorporating "folded-from-inverse-folded" (FIF) structures. To generate FIF structures, possible sequences are predicted from step-wise predictions in the reverse diffusion and further folded into new backbones. Being intrinsically designable, the FIF structures guide the generated backbones to a more designable distribution. Experiments on both de novo design and motif-scaffolding demonstrate improved designability and diversity with Amalga on RFdiffusion.

bioinformatics↗

bioRxiv2023

Protein thiol alterations drive aberrant phase separation in aging

Cellular homeostasis relies on precise regulation through chemical processes, such as protein posttranslational modifications (PTM) and physical processes, such as biomolecular condensation. Aging disrupts this balance, increasing susceptibility to diseases and death. However, the mechanisms behind age-related pathogenesis remain elusive. In this study, we dissected various cysteine PTMs and their impact on protein-mediated biomolecular condensation in aging brain. Our findings reveal that aging is associated with significant remodeling of cysteine PTMs, which impacts protein ability to participate in liquid-liquid phase separation (LLPS). Specifically, aging leads to an increase in protein sulfenylation and sulfonylation, which promotes LLPS and through conformational change increases the propensity of proteins to aggregate. Protein persulfidation, a protective thiol modification, prevents this by causing condensate dissolution. We demonstrate that age-induced alterations in cysteine PTMs influence the LLPS properties of synapsin-1 and G3BP2, resulting in disruptions in neurotransmitter release and stress granule formation, respectively. Additionally, our study uncovers that GAPDH is susceptible to LLPS and cysteine sulfonylation exacerbates its transition from condensates to aggregates. Mice deficient in cystathionine gamma-lyase, a pro-longevity gene that regulates intracellular persulfide levels, exhibit a shorter lifespan and spontaneous development of neurofibrillary tangles.

biochemistry↗

bioRxiv2023

Integrated multi-omics single cell atlas of the human retina

Single-cell sequencing has revolutionized the scale and resolution of molecular profiling of tissues and organs. Here, we present an integrated multimodal reference atlas of the most accessible portion of the mammalian central nervous system, the retina. We compiled around 2.4 million cells from 55 donors, including 1.4 million unpublished data points, to create a comprehensive human retina cell atlas (HRCA) of transcriptome and chromatin accessibility, unveiling over 110 types. Engaging the retina community, we annotated each cluster, refined the Cell Ontology for the retina, identified distinct marker genes, and characterized cis-regulatory elements and gene regulatory networks (GRNs) for these cell types. Our analysis uncovered intriguing differences in transcriptome, chromatin, and GRNs across cell types. In addition, we modeled changes in gene expression and chromatin openness across gender and age. This integrated atlas also enabled the fine-mapping of GWAS and eQTL variants. Accessible through interactive browsers, this multimodal cross-donor and cross-lab HRCA, can facilitate a better understanding of retinal function and pathology.

molecular biology↗

bioRxiv2023

Dynamic Regulation of Innate Lymphoid Cell Development During Ontogeny

Innate lymphoid cells (ILCs) are crucial for maintaining tissue homeostasis. The dynamic composition of ILC subsets during ontogeny has been observed for over a decade, yet the underlying mechanisms remain incompletely understood. Here, we combined differentiation assay and scRNA-seq analysis to compare the fetal and adult ILC development, and assessed their contribution to the dynamic change of ILC subsets. We revealed the preference for LTi cell differentiation in fetal hematopoietic progenitors, contrasted with a non-LTi differentiation bias in adult stages. Our analyses elucidated that the two stages shared a conserved differentiation trajectory and regulatory programs but used different controlling logic. Through computational prediction and dose-response experiments, we proposed a model where a transition from fetal ROR{gamma}t-dominant states to adult Notch-GATA3-dominant states orchestrates these changes. This study suggests that ILC development can be modulated to accommodate the varying demands for specific ILC subsets within the body at different developmental stages. HighlightO_LIThe ratio of LTi cells to non-LTi ILCs decreases from fetal to adult stage C_LIO_LIModified fate determination of ILC progenitors contributes to this decrease of LTi cell ratio during ontogeny C_LIO_LIA conserved trajectory exists from early LPs to Innate Lymphoid Cell Precursors (ILCPs) during both fetal and adult ILC development C_LIO_LIEnhanced activity of Notch-GATA3 signaling in ILC precursors accounts for the transition of their differentiation from LTi cells in the fetal to non-LTi ILCs in adults. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/565141v2_ufig1.gif" ALT="Figure 1"> View larger version (85K): org.highwire.dtl.DTLVardef@11a031eorg.highwire.dtl.DTLVardef@c2d652org.highwire.dtl.DTLVardef@184cdfeorg.highwire.dtl.DTLVardef@1efe7ae_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

Alteration in Gut Microbiome and Intestinal Barrier Function caused by Efavirenz versus Dolutegravir Treatments in Mice

Dolutegravir (DTG) is replacing efavirenz (EFV) as first-line antiretroviral therapy because of its better tolerance. However, DTG cause similar, but milder, gastrointestinal and neurological side effects as EFV does. We speculated that impaired gut barrier function contributes to their side effects. For this purpose, the mice were intragastrically administered EFV, DTG, or vehicle for 60 consecutive days. The plasma levels of FITC-dextran were determined to evaluate gut barrier integrity. Colonic contents were collected for 16S rRNA sequencing. Adipose, liver, ileum, and colon tissues were collected for pathological examination, and intestinal zona occludens-1 (ZO-1) immunofluorescence staining and goblet cell staining were performed. We found that EFV significantly retarded body weight gain, decreased glucose uptake, and caused lipodystrophy and hepatocyte necrosis. EFV also decreased species richness of gut microbiota, increased Verrucomicrobia and Proteobacteria, and decreased Patescibacteria and Cyanobacteria. Moreover, it caused crypt damage, goblet cell loss, reduced ZO-1 expression, impaired gut barrier function, and suppressed expressions of Pdha1 and Ndufv1. Interestingly, DTG impaired barrier function similar to EFV, but the impairment was milder. DTC also inhibited MPC1, MPC2, and Pdha1 expression. Our results suggest a link between abnormal energy metabolism, impaired gut barrier integrity and side effects of EFV and DTG.

immunology↗

bioRxiv2023

Differential chromatin accessibility and transcriptional dynamics define breast cancer subtypes and their lineages

Breast cancer is a heterogeneous disease, and treatment is guided by biomarker profiles representing distinct molecular subtypes. Breast cancer arises from the breast ductal epithelium, and experimental data suggests breast cancer subtypes have different cells of origin within that lineage. The precise cells of origin for each subtype and the transcriptional networks that characterize these tumor-normal lineages are not established. In this work, we applied bulk, single-cell (sc), and single-nucleus (sn) multi-omic techniques as well as spatial transcriptomics and multiplex imaging on 61 samples from 37 breast cancer patients to show characteristic links in gene expression and chromatin accessibility between breast cancer subtypes and their putative cells of origin. We applied the PAM50 subtyping algorithm in tandem with bulk RNA-seq and snRNA-seq to reliably subtype even low-purity tumor samples and confirm promoter accessibility using snATAC. Trajectory analysis of chromatin accessibility and differentially accessible motifs clearly connected progenitor populations with breast cancer subtypes supporting the cell of origin for basal-like and luminal A and B tumors. Regulatory network analysis of transcription factors underscored the importance of BHLHE40 in luminal breast cancer and luminal mature cells, and KLF5 in basal-like tumors and luminal progenitor cells. Furthermore, we identify key genes defining the basal-like (PRKCA, SOX6, RGS6, KCNQ3) and luminal A/B (FAM155A, LRP1B) lineages, with expression in both precursor and cancer cells and further upregulation in tumors. Exhausted CTLA4-expressing CD8+ T cells were enriched in basal-like breast cancer, suggesting altered means of immune dysfunction among breast cancer subtypes. We used spatial transcriptomics and multiplex imaging to provide spatial detail for key markers of benign and malignant cell types and immune cell colocation. These findings demonstrate analysis of paired transcription and chromatin accessibility at the single cell level is a powerful tool for investigating breast cancer lineage development and highlight transcriptional networks that define basal and luminal breast cancer lineages.

cancer biology↗

bioRxiv2023

Pathological claustrum activity drives aberrant cognitive network processing in human chronic pain

Aberrant cognitive network activity and cognitive deficits are established features of chronic pain. However, the nature of cognitive network alterations associated with chronic pain and their underlying mechanisms require elucidation. Here, we report that the claustrum, a subcortical nucleus implicated in cognitive network modulation, is activated by acute painful stimulation and pain-predictive cues in healthy participants. Moreover, we discover pathological activity of the claustrum and a lateral aspect of the right dorsolateral prefrontal cortex (latDLPFC) in migraine patients. Dynamic causal modeling suggests a directional influence of the claustrum on activity in this latDLPFC region, and diffusion weighted imaging (DWI) verifies their structural connectivity. These findings advance understanding of claustrum function during acute pain and provide evidence of a possible circuit mechanism driving cognitive impairments in chronic pain.

neuroscience↗

bioRxiv2023

APOE4 poses opposite effects of plasma LDL on white matter integrity in older adults

INTRODUCTIONAPOE4 is a strong genetic risk factor of Alzheimers disease and is associated with changes in metabolism. However, the interactive relationship between APOE4 and plasma metabolites on the brain remains largely unknown. MEHODSIn the UK Biobank, we investigated the moderation effects of APOE4 on the relationship between 249 plasma metabolites derived from nuclear magnetic resonance spectroscopy on whole-brain white matter integrity, measured by fractional anisotropy using diffusion magnetic resonance imaging. RESULTSThe increase in the concentration of metabolites, mainly LDL and VLDL, is associated with a decrease in white matter integrity (b= -0.12, CI= [-0.14, -0.10]) among older APOE4 carriers, whereas an increase (b= 0.05, CI= [0.04, 0.07]) among non-carriers, implying a significant moderation effect of APOE4 (b= -0.18, CI= [-0.20,-0.15]). DISCUSSIONThe results suggest that lipid metabolism functions differently in APOE4 carriers compared to non-carriers, which may inform the development of targeted interventions for APOE4 carriers to mitigate cognitive decline.

neuroscience↗

bioRxiv2023

A peptide-centric local stability assay to unveil protein targets of diverse ligands

While tremendous progress has been made in chemical proteomics for identifying protein-ligand interactions, it remains challenging for proteome-wide identification of ligand-binding regions without modifying the ligands. Here, we discovered that "disruptive trypsinization" amplifies the readout of ligand-induced protein local stability shifts, and explored this notion in developing "peptide-centric local stability assay" (PELSA), a modification-free approach which achieves unprecedented sensitivity in proteome-wide target identification and binding-region determination. We demonstrate the versatility of PELSA by investigating the interactions across various biological contexts including drug-target interactions, metabolism, epitope mapping, metal proteomics, and post-translational modification recognition. A PELSA study of the oncometabolite R2HG revealed functional insights about its targets and pathogenic processes in both cancer and immune cells. Thus, beyond offering users unprecedented sensitivity for characterizing diverse target-ligand interactions, PELSA supports informative screening and hypothesis generation studies throughout life science.

biochemistry↗