Biology subjects

Xie, N.

Publications and source records attributed to Xie, N..

13 recordsLinked to original sources

bioRxiv2026

Matrix stiffness shapes immunometabolic states and response to PD-1 blockade in gastric cancer

The extracellular matrix of solid tumors exhibits spatially heterogeneous stiffness, yet how matrix stiffness shapes antitumor immunity in gastric cancer (GC) remains unclear. Here, we integrated anti-PD-1 clinical cohorts, GC specimens, single-cell and spatial transcriptomic analyses, a syngeneic mouse model, and tunable-stiffness hydrogels to clarify the immunological consequences of matrix stiffness. High matrix stiffness was associated with collagen accumulation and immune exclusion, while higher stiffness-associated transcriptional scores were related to poorer response to PD-1 blockade. Matrix softening markedly reshaped the immune microenvironment and enhanced the efficacy of PD-1 blockade. Mechanistically, stiff matrices promoted F-actin remodeling and YAP nuclear enrichment, driving LDHA-dependent glycolytic reprogramming in GC cells that further impaired the effector function of CD8 T cells. Intriguingly, matrix softening was accompanied by enhanced IFN-{gamma}-responsive PD-L1 expression in GC cells, consistent with adaptive immune resistance that may contribute to the limited antitumor effects of matrix softening alone. These findings suggest that matrix remodeling alleviates spatial and metabolic constraints on antitumor immunity, providing a preclinical rationale for combining matrix softening with PD-1 blockade in GC.

cancer biology↗

bioRxiv2026

Persistent Post-Inflammatory Matrix Stiffening Defines a Premalignant Mechanical Niche in Ulcerative Colitis-Associated Neoplasia

Patients with long-standing ulcerative colitis (UC) remain at risk for colorectal neoplasia even after overt inflammatory activity improves, suggesting that repaired mucosa may retain residual tissue-level abnormalities. Whether extracellular matrix remodeling leaves a persistent mechanical cue that contributes to early neoplastic remodeling is unknown. Here we identify post-inflammatory matrix stiffening as a premalignant mechanical niche in UC-associated neoplasia. In human colonic biopsies, collagen remodeling and atomic-force-microscopy-based mucosal stiffness increased from non-UC controls to UC and UC-associated dysplasia. A stiffness-associated transcriptional program was also enriched in histologically non-dysplastic mucosa from patients with UC-associated neoplasia. In mouse models, colonic stiffness increased along the colitis-to-tumorigenesis axis and remained elevated during apparent recovery, when epithelial permeability, junctional protein loss, crypt proliferation and nuclear {beta}-catenin accumulation persisted despite reduced disease activity. Stiffness-controlled intestinal epithelial cultures showed that stiff substrates were sufficient to disrupt ZO-1 organization and enhance {beta}-catenin redistribution, particularly under TNF- stimulation. Pharmacological matrix normalization with {beta}-aminopropionitrile partially restored barrier organization and attenuated early epithelial remodeling in vivo. Single-cell profiling identified a stiffness-associated MMP7-positive/YAP-active epithelial state that was enriched in collagen-rich regions and reduced after matrix softening. Inhibition of YAP or MMP7 attenuated stiffness-associated junctional disruption and {beta}-catenin redistribution. These findings suggest that inflammatory recovery and mechanical recovery can be uncoupled, and that persistent mucosal stiffening provides a tissue-level mechanism by which chronically injured UC mucosa may remain biologically vulnerable to premalignant epithelial remodeling.

Cancer Biology↗

bioRxiv2025

Unveiling the Biochemical Mechanisms of Aging and the Implications of Oxidative Stress on Cellular Senescence through Multi-Omics Analysis of Fibroblasts

This research investigates the complex biochemical mechanisms underlying aging by analyzing primary human fibroblasts using a longitudinal multi-omics dataset. This dataset includes cytology, DNA methylation and epigenetic clocks, bioenergetics, mitochondrial DNA sequencing, RNA sequencing, and cytokine profiling. Key findings indicate that mitochondrial efficiency declines with age, while glycolysis becomes more prevalent to compensate for energy demands. Epigenetic clocks, such as Hannum and PhenoAge, showed strong correlations with biological age ({rho} > 0.650, p < 1e-6), validating the experimental setup and confirming that the cultured fibroblasts were aging appropriately. Fibroblasts with SURF1 mutations exhibited accelerated aging, marked by bioenergetic deficits, increased cell volume, and reduced proliferative capacity, underscoring the pivotal role of mitochondrial dysfunction in cellular senescence. Novel insights were gained from analyzing cytokines like IL18 and PCSK9, some of which were linked to age-related diseases such as Alzheimers and cardiovascular disorders. Experimental treatments revealed distinct effects on cellular aging. Dexamethasone reduced inflammation but also increased DNA methylation, induced metabolic inefficiencies, and shortened cellular lifespan. Oligomycin heightened oxidative stress and RNA degradation, emphasizing how such treatments contribute to cellular stress and metabolic imbalance while shedding light on aging mechanisms. By uncovering connections between mitochondrial dysfunction, epigenetic biomarkers, and immune dysregulation, this study identifies potential therapeutic targets for age-related diseases. Future research could validate the most promising biomarkers across diverse cell types and experimental treatments to build a more comprehensive understanding of aging.

genomics↗

bioRxiv2024

LEGEND: Identifying Co-expressed Genes in Multimodal Transcriptomic Sequencing Data

Identifying co-expressed genes across tissue domains and cell types is essential for revealing co-functional genes involved in biological or pathological processes. While both single-cell RNA-sequencing (scRNA-seq) and spatially-resolved transcriptomic (SRT) data offer insights into gene co-expression patterns, current methods typically utilize either data type alone, potentially diluting the co-functionality signals within co-expressed gene groups. To bridge this gap, we introduce LEGEND, a novel computational method that integrates scRNA-seq and SRT data for identifying groups of co-expressed genes at both cell type and tissue domain levels. LEGEND employs an innovative hierarchical clustering algorithm designed to maximize intra-cluster redundancy and inter-cluster complementarity, effectively capturing more nuanced patterns of gene co-expression and spatial coherence. Enrichment and cofunction analyses further showcase the biological relevance of these gene clusters, and their utilities in exploring context-specific novel gene functions. Notably, LEGEND can reveal shifts in gene-gene interactions under different conditions, furnishing insights for disease-associated gene crosstalk. Moreover, LEGEND can be utilized to enhance the annotation accuracy of both spatial spots in SRT and single-cells in scRNA-seq, and pioneers in identifying genes with designated spatial expression patterns. LEGEND is available at https://github.com/ToryDeng/LEGEND.

genomics↗

bioRxiv2024

Clinical characteristics, drug-resistance genes and virulence analysis of carbapenem-resistant Klebsiella pneumoniae

OBJECTIVEThe aim was to investigate the clinical infection characteristics, risk factors and convergence of carbapenem-resistant and hypervirulent Klebsiella pneumoniae(hv-CRKP) in our hospital, in order to provide scientific basis for the rational use of antibiotics in the clinic. METHODSCRKP strains were isolated from clinical specimens of 44 patients in central intensive care unit (CICU), neurosurgery intensive care unit (NICU) and emergency intensive care unit (EICU) of our hospital in 41 months. The clinical manifestations of the patients were analyzed, and the hypermucoviscous phenotype was defined by string test. The drug resistance gene, virulence gene and capsular specific serotype of the isolated strains were detected by polymerase chain reaction (PCR) technology, and the gene of CRKP producing KPC enzyme was sequence. RESULTSThe incidence of sepsis in 44 patients with CRKP infection was 25.0%, and the overall treatment failure rate was 38.6%. All the 44 strains of CRKP produced KPC enzyme, and all of them were blaKPC-2 (100%);14 strains (31.8%) were positive in string test; 23 strains (52.3%) were found to have virulence related genes, including 10 strains (22.7%) of rmpA, 16 strains (36.4%) of iucA and 19 strains (43.2%) of peg-344. 5 strains (11.4%) were capsule-specific serotypes and 13 strains (29.5%) were identified as hv-CRKP. CONCLUSIONThe mechanism of CRKP resistance in our hospital is blaKPC-2, the detection rates of virulence gene, string test positive and hypervirulent capsular specific serotype are all relatively high in CRKP, there are not a few Klebsiella pneumoniae with carbapenem-resistant and hypervirulent.

microbiology↗

bioRxiv2024

Rac1 and Nectin3 are essential for PCP-directed axon guidance in the peripheral auditory system

Our sense of hearing is critically dependent on the spiral ganglion neurons (SGNs) that connect the sound receptors in the organ of Corti (OC) to the cochlear nuclei of the hindbrain. Type I SGNs innervate inner hair cells (IHCs) to transmit sound signals, while type II SGNs (SGNIIs) innervate outer hair cells (OHCs) to detect moderate-to-intense sound. During development, SGNII afferents make a characteristic 90-degree turn toward the base of the cochlea and innervate multiple OHCs. It has been shown that the Planar Cell Polarity (PCP) pathway acts non-autonomously to mediate environmental cues in the cochlear epithelium for SGNII afferent turning towards the base. However, the underlying mechanisms are unknown. Here, we present evidence that PCP signaling regulates multiple downstream effectors to influence cell adhesion and the cytoskeleton in cochlear supporting cells (SCs), which serve as intermediate targets of SGNII afferents. We show that the core PCP gene Vangl2 regulates the localization of the small GTPase Rac1 and the cell adhesion molecule Nectin3 at SC-SC junctions through which SGNII afferents travel. Through in vivo genetic analysis, we also show that loss of Rac1 or Nectin3 partially phenocopied SGNII peripheral afferent turning defects in Vangl2 mutants, and that Rac1 plays a non-autonomous role in this process in part by regulating PCP protein localization at the SC-SC junctions. Additionally, epistasis analysis indicates that Nectin3 and Rac1 likely act in the same genetic pathway to control SGNII afferent turning. Together, these experiments identify Nectin3 and Rac1 as novel regulators of PCP-directed SGNII axon guidance in the cochlea. Significance statementPlanar Cell Polarity (PCP) signaling plays a non-autonomous role in the guidance of type II spiral ganglion neuron (SGNII) afferent projections that innervate cochlear hair cells. However, little is known about the underlying mechanisms. Here, we identify the small GTPase Rac1 and the cell adhesion molecule Nectin3 as two downstream effectors of PCP signaling in SGNII afferent guidance. We show that PCP signaling regulates Rac1 and Nectin3 localization in cochlear supporting cells that serve as intermediate targets for SGNII afferents and that Rac1 and Nectin3 likely act in the same genetic pathway to non-autonomously regulate SGNII afferent guidance. These findings significantly advance our understanding of auditory circuit assembly and shed light on PCP-directed axon guidance mechanisms.

developmental biology↗

bioRxiv2024

Soil viruses reduce greenhouse gas emissions and promote microbial necromass accrual

Viral-induced microbial mortality has been proposed as a major contributor in shaping microbial community structure and function, soil carbon (C) accrual and mobilization of plant available nutrients. Yet, how soil viruses influence soil organic C (SOC) turnover and sequestration remains unknown. Here, we performed microcosm experiments with two distinct soils from grassland (GL) and agricultural (AG) sites and interrogated the roles of soil viruses in driving microbial community succession, SOC transformation and sequestration. The results show that soil viruses affected microbial C use efficiency and reduced respiration in microbial communities obtained from both GL and AG soils. Soil viruses affected microbial successional trajectories (via predation of dominant populations) and functional gene profiles triggering a significant decrease in CO2 and N2O emissions. The impact of soil viruses on microbial community composition in GL microcosms was much less pronounced compared with that in AG microcosms, suggesting contrasting virus-host interaction patterns under different environmental settings. Viral infection significantly enhanced microbial necromass accumulation thereby increasing SOC and total nitrogen (TN) content. The results implicate viral-mediated microbial mortality as a key factor influencing the distribution of C between mineralization and soil C storage pathways. We proposed "viral loop" to explain the crucial function of soil viruses in SOC turnover and sequestration.

ecology↗

bioRxiv2024

Dark respiration modulates photosynthetic carbon yield in cyanobacteria

Cyanobacteria contribute to roughly a quarter of global net carbon fixation. During diel light/dark growth, dark respiration significantly lowers the overall photosynthetic carbon yield in cyanobacteria and other phototrophs. Currently, it is unclear how respiratory pathways participate in allocating carbon resources at night to optimize dark survival and support daytime photosynthesis. Here we show in the cyanobacterium Synechococcus elongatus PCC 7942 that phosphoketolase is orchestrated in an integrative respiratory network in the dark to best allocate carbon resource for amino acid synthesis and prepare for photosynthesis reinitiation upon photoinduction. We further show that the respiratory Entner-Doudoroff (ED) pathway in S. elongatus is incomplete, with its key enzyme 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase serving to modulate daytime photosynthesis through an alternative oxaloacetate decarboxylation activity. This activity allows for the bypassing of the tricarboxylic acid (TCA) cycle when ATP/NADPH consumption for biosynthesis is excessive and imbalanced relative to their production by light reactions, thereby preventing relative NADPH accumulation and ensuring optimal photosynthetic carbon yield. Optimizing these metabolic processes offers new opportunities to enhance photosynthetic carbon yield in cyanobacteria and other photosynthetic organisms under diel light/dark cycles.

biochemistry↗

bioRxiv2024

Targeting resident astrocytes attenuates neuropathic pain after spinal cord injury

Astrocytes derive from different lineages and play a critical role in neuropathic pain after spinal cord injury (SCI). Whether selective eliminating these main origins of astrocytes in lumbar enlargement could attenuate SCI-induced neuropathic pain remains unclear. Through transgenic mice injected with an adeno-associated virus vector and diphtheria toxin, astrocytes in lumbar enlargement were lineage traced, targeted and selectively eliminated. Pain-related behaviors were measured with an electronic von Frey apparatus and a cold/hot plate after SCI. RNA sequencing, bioinformatics analysis, molecular experiment and immunohistochemistry were used to explore the potential mechanisms after astrocyte elimination. Lineage tracing revealed that the resident astrocytes but not ependymal cells were the main origins of astrocytes-induced neuropathic pain. SCI induced mice to obtain significant pain symptoms and astrocyte activation in lumbar enlargement. Selective resident astrocytes elimination in lumbar enlargement could attenuate neuropathic pain and activate microglia. Interestingly, the type I interferons (IFNs) signal was significantly activated after astrocytes elimination, and the most activated Gene Ontology terms and pathways were associated with the type I IFNs signal which was mainly activated in microglia and further verified in vitro and in vivo. Furthermore, different concentrations of interferon and Stimulator of interferon genes (STING) agonist could activate the type I IFNs signal in microglia. These results elucidate that selectively eliminating resident astrocytes attenuated neuropathic pain associated with type I IFNs signal activation in microglia. Targeting type I IFNs signal is proven to be an effective strategy for neuropathic pain treatment after SCI.

neuroscience↗

bioRxiv2023

In vivo PSC differentiation as a platform to identify factors for improving the engraftability of cultured muscle stem cells

Producing an adequate number of muscle stem cells (MuSCs) with robust regenerative potential is essential for the successful cell therapy of muscle-wasting disorders. We have recently developed a method to produce skeletal myogenic cells with exceptional engraftability and expandability through an in vivo pluripotent stem cell (PSC) differentiation approach. We have subsequently mapped engraftment and gene expression and found that leukemia inhibitory factor receptor (Lifr) expression is positively correlated with engraftability. We therefore investigated the effect of LIF, the endogenous ligand of LIFR, on cultured MuSCs and examined their engraftment potential. We found that LIF-treated MuSCs exhibited elevated expression of PAX7, formed larger colonies from single cells, and favored the retention of PAX7+ "reserve cells" upon myogenic differentiation. This suggested that LIF promoted the maintenance of cultured MuSCs at a stem cell stage. Moreover, LIF enhanced the engraftment capability of MuSCs that had been expanded in vitro for 12 days by 5-fold and increased the number of MuSCs that repopulated the stem cell pool post-transplantation. These results thereby demonstrated the effectiveness of our in vivo PSC differentiation platform to identify positive regulators of the engraftability of cultured MuSCs.

cell biology↗

bioRxiv2023

The Interferon-inducible NAMPT acts as a protein phosphoribosylase to restrict viral infection

As obligate intracellular pathogens, viruses often activate host metabolic enzymes to supply intermediates that support progeny production. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the salvage NAD+ synthesis, is an interferon-inducible protein that inhibits the replication of several RNA and DNA viruses with unknown mechanism. Here we report that NAMPT restricts herpes simplex virus 1 (HSV-1) replication via phosphoribosyl-hydrolase activity toward key viral structural proteins, independent of NAD+ synthesis. Deep mining of enriched phosphopeptides of HSV-1-infected cells identified phosphoribosylated viral structural proteins, particularly glycoproteins and tegument proteins. Indeed, NAMPT de-phosphoribosylates viral proteins in vitro and in cells. Chimeric and recombinant HSV-1 carrying phosphoribosylation-resistant mutations show that phosphoribosylation promotes the incorporation of structural proteins into HSV-1 virions and subsequent virus entry. Moreover, loss of NAMPT renders mice highly susceptible to HSV-1 infection. The work describes a hidden enzyme activity of a metabolic enzyme in viral infection and host defense, offering a system to interrogate roles of phosphoribosylation in metazoans.

molecular biology↗

bioRxiv2022

CRISPR screens reveal genetic determinants of PARP inhibitor sensitivity and resistance in prostate cancer

Prostate cancer (PCa) harboring BRCA1/2 mutations is often exquisitely sensitive to PARP inhibition. However, genomic alterations in other DNA damage response genes have not been consistently predictive of clinical response to PARP inhibitors (PARPis). Here, we perform genome-wide CRISPR-Cas9 knockout screens in BRCA1/2-proficient PCa cell lines and identify novel genes whose loss has a profound impact on PARPi sensitivity and resistance. Specifically, MMS22L deletion, frequently observed (up to 14%) in PCa, renders cells hypersensitive to PARPis by disrupting RAD51 loading required for homologous recombination repair, although this response is TP53-dependent. Unexpectedly, loss of CHEK2 confers resistance rather than sensitivity to PARPis in PCa cells through increased expression of BRCA2, a target of CHEK2-TP53-E2F7-mediated transcriptional repression. Combined PARP and ATR inhibition overcomes PARPi resistance caused by CHEK2 loss. Our findings may inform the use of PARPis beyond BRCA1/2-deficient tumors and support reevaluation of currently used biomarkers for PARPi treatment in PCa.

cancer biology↗

bioRxiv2018

The Biology of Risk-On. Decreasing Inflammatory and Stress Responses on a London Trading Floor

Human physiological arousal is highly sensitive to information and uncertainty. Little is known, however, about how to measure information in natural settings, nor about which physiological systems respond to it. Financial market prices, and their volatility, present a convenient measure of informational load. Here we report on a study into the physiological response of traders in the City of London during a period of extreme, but declining, volatility. We sampled salivary cortisol, the main stress hormone, and the pro-inflammatory cytokines, IL-1{beta}, IL-6, IL-8, and TNF- three times a day for two weeks. We found that average daily cortisol levels tracked closely an index of equity and bond volatility, as did levels of IL-1{beta}. Within-day cortisol and IL-1{beta} levels also tracked one hour lagged volatility. Interestingly, the cascade of endocrine and immunological changes was initiated by IL-1{beta}, the first responder of the stress and inflammatory responses. Our results have implications for finance because chronic stress and the immune response known as sickness behaviour could have powerful effects on risk-taking and market stability.

physiology↗