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Chen, Y.

Publications and source records attributed to Chen, Y..

At least 289 records · Page 16Linked to original sources

Rapid Podocyte ablation Causes Acute Renal Tubule Cell Necrosis and Interstitial Fibrosis

It remains unclear whether podocyte loss directly causes acute renal tubular cell (RTC) damage and interstitial fibrosis, thereby leading to renal failure. Here, we applied intermedilysin (ILY)-mediated human CD59 (hCD59) cell ablation to generate an acute, specific podocyte-ablation mouse model. Cre-induced hCD59 transgenics (ihCD59) were crossed with Nphs2Cre to generate ihCD59+/-/Nphs2Cre+/- mice. The specific and rapid podocyte-ablation mediated by ILY injection directly caused RTC necrosis, leading to renal failure and even death within 2-3 days in a dose-dependent manner. Treating mice that received an ILY lethal dose with peritoneal dialysis or administering a non-lethal dose, we extended their survival beyond six weeks and found that mice developed interstitial fibrosis and glomerulosclerosis with persistent proteinuria and tubule damage. Podocyte-ablation caused massive disruption of glomerular function at week 1, and then partial recovery by week 2. Genes and pathways of TLRs and apoptosis, and mitochondrial functions were respectively upregulated and downregulated in both ablated-podocyte mouse and biopsied-glomerulonephritis patient kidney samples. Together, this rapid podocyte-ablation causes acute RTC necrosis that progresses to interstitial fibrosis in this mouse model, which is applicable for dissecting mechanisms underlying podocyte injury-mediated tubular damage and glomerular repair, with the potential to reveal novel therapeutic targets for kidney diseases.

pathology↗

Gq-pathway activation in hippocampal CA1 astrocytes rescues ischemia-induced memory deficits and synaptic plasticity

More than 30% of stroke survivors develop post-stroke cognitive impairment (PSCI), for which current neuron-centric therapies not only lack cellular specificity but also carry risks of adverse effects such as epilepsy. Here, we explore the therapeutic potential of astrocytes by chemogenetically activating Gq signaling in hippocampal astrocytes, which rescues memory deficits and synaptic plasticity impairments in a mouse model of ischemic stroke. Gq activation restores dendritic complexity, spine density, and long-term potentiation in hippocampal CA1 neurons. Fiber photometry further reveals that astrocytic Ca{superscript 2} signals precede neuronal activity by 600 ms during novel environment exploration, indicating that astrocytes prime memory encoding. In contrast, Gi pathway activation induces pathological neuronal hyperactivity without cognitive improvement. These findings establish that astrocytes regulate post-stroke recovery through pathway-specific calcium signaling and uncover a previously unknown temporal hierarchy in astrocyte-neuron communication during memory processing, offering a new glia-targeted strategy to overcome the limitations of current neuromodulation approaches for PSCI.

neuroscience↗

Defining influenza-specific B cells in vaccine responders, non-responders and influenza breakthrough infections

Although seasonal influenza vaccination programs are effective at a population level, our data from inactivated influenza vaccine (IIV) cohorts in years 2015-2022 reveal that 50-60% of individuals do not seroconvert following immunization. The underlying mechanisms of vaccine non-responsiveness are far from understood. In this study, we sought to define key determinants of optimal B cell immune responses elicited by seasonal influenza vaccination, and to explore why some individuals fail to elicit humoral immunity following immunization. Immune responses associated with seroconversion and vaccine failure from individuals immunized with IIVs were compared at cellular and molecular levels using single-cell transcriptomics. We analyzed HA-specific B cell immunity across vaccine-responders, breakthrough infections and patients hospitalized with acute influenza. Droplet-based single-cell RNA sequencing and VDJ-sequencing of influenza-specific B cells from stored PBMCs was performed using 10x Genomics. Our results show that atypical B cells are the major subset of B cell responses in vaccine non-responders on day 28 post-vaccination. Conversely, individuals who seroconvert had diverse B cell phenotypes. The use of recombinant influenza-specific HA probes allowed us to dissect expression patterns on influenza HA-specific B cells. We found that HA-specific B cells of vaccine non-responders for A/H1N1 and A/H3N2 components displayed elevated atypical-like markers (CD11c, FcRL-5) at baseline, compared to responders. Analysis of differentially expressed genes (DEGs) between responders and non-responders identified differential expression of HLA-DR, CD74, CD83, and CXCR3 genes. We subsequently demonstrated reduced frequencies of HLA-DR-, CD74- and CD83-expressing B cells in patients hospitalized with influenza, compared to healthy participants. Hospitalized influenza patients also had significantly higher proportions of atypical CD21-CD27- B cells. Overall, our data demonstrate an association between elevated frequencies of atypical-like B cells with both lack of seroconversion following immunization and severe influenza infection. These findings broaden our understanding of humoral immunity in influenza vaccination and infection, providing novel insights for vaccination strategies and design.

immunology↗

The enhanced multi-tissue atlas of regulatory effects in cattle

Cattle are integral to global food security, yet the molecular architecture of their complex traits remains poorly understood. Here, we present the Cattle Genotype-Tissue Expression (CattleGTEx) Phase 1 resource (https://cattlegtex.farmgtex.org/), a substantial expansion of the pilot study. By leveraging 12,422 RNA-seq profiles across 43 tissues and 82 breeds, we characterized 433,972 primary and 161,428 non-primary regulatory effects spanning seven molecular phenotypes. This high-resolution atlas resolves 75% of GWAS signals for 44 complex traits, significantly addressing the "missing regulation" in livestock. We propose a genetic regulatory model demonstrating how variants across multiple biological layers interact with specific biological contexts to shape phenotypic variation. Furthermore, CattleGTEx elucidates mechanisms underlying adaptive evolution between Bos taurus and Bos indicus, as well as artificial selection in dairy and beef breeds. Finally, by mapping evolutionary constraints on these regulatory effects, we demonstrate the translational value of this resource for prioritizing causal variants in human complex diseases. Together, Phase 1 of CattleGTEx provides a transformative framework for functional genomics, precision breeding, and comparative genetics.

genetics↗

Neutrophils are critical for placental and fetal infection with the human pathogen Listeria monocytogenes

Fetal listeriosis, caused by Listeria monocytogenes (Lm), represents a severe infectious disease. During pregnancy, the unique intrauterine environment permits Lm to breach the maternal-fetal barrier by infiltrating the placental trophoblast layer and ultimately leading to significant fetal morbidity and mortality. However, the exact pathways remain incompletely understood. In this study, we sought to elucidate the molecular mechanisms underlying the early stages of placental and fetal Lm infection. Our results reveal that neutrophils serve as a survival niche for Lm within the vasculature, facilitating placental and fetal infection in the mouse in vivo. This finding was further substantiated by in vitro studies using TLR2-stimulated trophoblast cells and Lm-infected neutrophils. Additionally, tissue-clearing analysis of Lm-infected placentas demonstrated neutrophil colocalization with Lm is rare within placental tissue. Collectively, our findings identify maternal neutrophils as an essential viability niche for Lm enabling their entry into trophoblast cells, thereby promoting placental and fetal infection. One Sentence SummaryMaternal circulating neutrophils act as survival niche for Listeria monocytogenes and facilitate placental/fetal infection with Listeria during pregnancy.

immunology↗

The impact of low-frequency genetic variants on serum protein levels

The mapping of protein quantitative trait loci (pQTLs) can provide molecular links between genotype and phenotype. Most such studies focus on common variants, but the effects of low-frequency (LF) variants remain underexplored. Focusing on cis-pQTLs, we integrated serum measurements of 7,596 proteins with genomic data, including LF variants (minor allele frequency [MAF] 0.1-1%), in 5,291 Icelanders to identify independent cis-pQTLs for 2,166 SOMAmers. Incorporating LF variants increased the number of detected genetic signals per protein, demonstrating widespread allelic heterogeneity in cis-acting regulation of serum proteins. LF pQTLs were enriched for coding variants in the respective protein-encoding gene, but also among distal secondary signals, revealing additional regulatory layers not captured by common variants alone. Proteins affected by common variant cis-pQTLs were more often secreted and exhibited tissue-specific expression, whereas proteins exclusively affected by LF variants were primarily from more constrained and biologically essential pathways. Expanding both protein coverage and the allele-frequency spectrum reveals a more complex and heterogeneous cis-regulatory architecture of circulating proteins.

genomics↗

Functional impact of PCSK9 variants on LDL uptake in a knockout hepatic model

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a central regulator of low-density lipoprotein (LDL) cholesterol metabolism, yet the functional consequences of many clinically observed PCSK9 variants remain unknown. To establish a rigorous system for quantitative variant assessment, we generated a PCSK9 knockout (KO) HepG2 cell line through CRISPR/Cas9-mediated deletion of exons 2-8, effectively removing both the prodomain and catalytic regions required for PCSK9 function. This null background enabled systematic functional mapping of wild-type (WT) PCSK9 and multiple clinically relevant variants representing well-characterized, recurrent, and previously understudied alleles. Functional assays revealed pronounced heterogeneity among variant activities. The classical gain-of-function (GOF) variants D374Y and R496W exhibited robust suppression of LDL uptake, whereas A443T--an infrequently reported and previously uncharacterized variant--demonstrated a loss-of-function (LOF)-like phenotype with significantly enhanced LDL uptake. Additional poorly characterized variants, including V4I, R104C/V114A, and R496W/N425S, displayed minimal functional profiles, providing novel mechanistic insights. Surface LDL receptor (LDLR) levels generally correlated with LDL uptake but revealed unique patterns for specific variants. This KO-based rescue system provides a high-resolution framework for mechanistic classification of both established and poorly characterized PCSK9 variants, bridging the gap between genetic discovery and functional interpretation while supporting precision lipid-lowering strategies.

biochemistry↗

AetherCell: A generative engine for virtual cell perturbation and in vivo drug discovery

Virtual cell modeling is currently hindered by a "data-utility paradox": biological information is fragmented between context-rich clinical RNA-seq and perturbation-dense experimental assays, leading to poor predictive generalization in human contexts. Here, we introduce AetherCell, a generative foundation model that unifies these disparate domains into a shared, platform-aligned transcriptomic manifold. By implementing a specificity-driven learning framework, AetherCell successfully recovers low-frequency, mechanism-specific signals often obscured by systematic noise. Across extensive benchmarks, AetherCell demonstrates robust generalization, accurately predicting responses to unseen compounds and genetic perturbations. We show that the model effectively translates signals from simple cell lines to complex 3D organoids, achieving high-fidelity, whole-transcriptome prediction. Building on this foundational manifold, we demonstrate precise drug response prediction across biological scales--including patient-derived organoids and clinical cohorts. We also implement a phenotype-knowledge mixture-of-experts strategy for precision drug repurposing. This approach is validated by the in vivo discovery of teriflunomide for dry eye disease and dabigatran for ulcerative colitis. Together, AetherCell establishes a scalable, human-centric virtual cell framework for translational biology and accelerated drug discovery.

bioinformatics↗

DCS Tools: A high-performance, resource-efficient and scalable computing suite for population-scale genomic analysis and data compression

The advent of population-scale genomics has created significant bottlenecks in computational infrastructure and storage. Traditional BWA-GATK Best Practices require massive resources, while most existing acceleration solutions depend on specialized hardware like GPUs or FPGAs, increasing costs and limiting deployment. To address this, we developed DCS Tools, a high-performance suite optimized for standard CPU architectures. DCS Tools processes a 30X WGS sample from raw FASTQ to variant calls in just 1.79 hours on a 32-thread instance--a 16-fold speedup over traditional pipelines without additional hardware. The suite integrates DPGT for million-scale joint calling and introduces SeqArc and VarArc, which reduce storage footprints by up to 80% (FASTQ) and 66% (VCF) compared to GZIP. DCS Tools offers a cost-effective, hardware-agnostic solution for petabyte-scale genomic analysis.

bioinformatics↗

In vivo-compatible spatial multi-omics via hydrogen peroxide-independent APEX2 labeling

Proximity labeling (PL) technologies like APEX2 have transformed spatial multi-omics in live cells, but their long-standing dependence on hydrogen peroxide (H2O2) disrupts redox signaling and prevents use in live animals. Here we introduce H2O2-independent APEX2 (Hi-APEX), which uses a clickable tetrazine-phenol probe, requiring no enzyme engineering. We show that APEX2 directly catalyzes TP radical formation without H2O2 via a mechanism requiring the probes tetrazine group and a key histidine residue. We benchmarked Hi-APEX-based spatial multi-omics by mapping the mitochondrial matrix and dynamic secretomes. Hi-APEX significantly outperforms traditional APEX in capturing redox-sensitive processes such as stress response and ferroptosis, enabling discovering authentic stress granule components and protein interaction networks for mitochondria-localized GPx4. One mGPx4 interactor TRMT61B--known to regulate mitochondrial m{superscript 1}A modifications--promotes ferroptosis. Crucially, Hi-APEX achieves full in vivo compatibility, enabling direct PL in tumor xenografts and hippocampal neurons, thereby expanding PL-based spatial multi-omics from cellular systems to living organisms.

biochemistry↗

Comprehensive long-read transcriptome analysis uncovers alternative RNA processing feature and isoform diversity in ovarian cancer progression

Post-transcriptional processing has a crucial yet largely unresolved dynamic change and role during the malignant progression of ovarian cancer, especially due to the limited read length of short-read RNA sequencing being insufficient to capture transcript diversity. Here, we performed Iso and RNA sequencing on paired normal, primary tumor, and metastatic samples, generating a comprehensive isoform atlas of over 41,000 full-length transcripts including many unannotated isoforms. Integrative analyses revealed extensive isoform-level remodeling across disease states that often occurred without concordant alterations at the gene level, emphasizing the importance of qualitative transcript regulation. Notably, we identified isoform-level alterations with distinct biological and clinical relevance, including differential expression of the short KRAS isoform, a tumor-specific isoform switch of TMEM201, and an alternative first-exon event in FNDC3B associated with poor survival. Together, these findings provide a high-resolution map of the ovarian cancer transcriptome and illustrate how long-read sequencing exposes multiple layers of post-transcriptional and clinical insight that remain hidden in conventional expression profiling.

bioinformatics↗

Efficient Reprogramming of the Epiblast Enables the Generation of Cloned Mice

Somatic cell nuclear transfer (SCNT) can generate viable mammals despite pervasive epigenetic abnormalities in cloned embryos, yet the mechanism underlying this paradox remains unclear. Here we show, using single-cell transcriptomics, that efficient reprogramming occurs exclusively in the epiblast (EPI), but the not primitive endoderm (PrE) of late mouse SCNT blastocysts. Integrating this with previous findings of trophectoderm (TE) aberration, we propose the EPI as the sole effectively reprogrammed lineage. By innovatively employing a Lego-like multi-lineage embryonic aggregation approach, where the extra-embryonic lineages were replaced with fertilization-derived counterparts, we demonstrated that SCNT-derived EPI inherently possesses full-term developmental potential nearly identical to that of fertilized EPI (20.5% vs. 21.8% birth rate), functionally confirming its effective reprogramming. Our study uncovers a lineage-specific asymmetric reprogramming mode where the EPI specifically achieves effective reprogramming, thereby constituting the deterministic basis for cloned animal generation. This work also provides a versatile strategy for investigating lineage potency and function.

developmental biology↗

The m6A Landscapes on the RNA of Mumps Virus and the Host 3 Modulate the Viral Replication and Antiviral Innate Immunity

N6-methyladenosine (m6A) is the most prevalent internal modification in eukaryotic mRNA and has emerged as a critical regulator of RNA virus infection. However, its role in the mumps virus (MuV), a non-segmented negative-strand (NNS) RNA virus, remains undefined. Here, we comprehensively characterize the m6A epitranscriptome of MuV JL2 strain and its functional impact on viral replication and host innate immunity. Using single-base resolution GLORI-seq, we identified abundant m6A modifications on MuV genomic, antigenomic and messenger RNAs, with uneven distribution and non-canonical motif enrichment. Genetic depletion of METTL3 enhanced viral replication by facilitating RNA synthesis and nucleocapsid encapsidation in Vero-E6 cells. In epithelial A549 and monocytoid THP1-iDC cells, MuV infection triggered robust type I/III interferon and proinflammatory responses by activating multiple pattern recognition receptors in a m6A-dependent manner and induced incomplete iDC maturation characterized by downregulated HLA class II; however, the latter molecule can be partially restored by METTL3-knockdown. The MuV infection reshaped the host m6A landscape with a positive correlation between m6A enrichment and transcripts enhancement of numerous innate immune genes in a cell type-specific manner. Functional analyses revealed that host m6A machinery modulates antiviral signaling, which varies between viral infection and viral RNA-transfection due to the infection-induced host m6A machinery fluctuation. Collectively, our findings demonstrate that m6A serves as a bidirectional regulator during MuV infection, simultaneously constraining viral replication and modulating host immune recognition, thereby highlighting RNA methylation as a pivotal determinant of MuV pathogenesis and a potential target for optimized immunogenicity. ImportanceN6-methyladenosine (m6A) modification has emerged as a key regulator of RNA virus infection, yet its role in mumps virus (MuV) remains undefined. Here we map the single-base resolution m6A landscape of a recombinant MuV and demonstrate that viral m6A restricts genome encapsidation and replication while attenuating innate immune sensing. MuV infection extensively remodels host m6A profiles in epithelial and dendritic cells, preferentially enhancing methylation of innate immune transcripts. Strikingly, m6A-deficient MuV RNA exhibits increased affinity for RIG-I-like and Toll-like receptors, eliciting stronger interferon and proinflammatory responses. Our findings identify m6A as a bidirectional regulator of MuV replication and immunity and suggest an epitranscriptomic strategy to optimize live-attenuated vaccine design.

immunology↗

Volume regulation of cancer cells during osmotic pressure variation

Osmotic pressure is a fundamental physical determinant of cellular homeostasis, and its perturbation is recognized as a critical factor in cancer progression and therapy. However, whether cancer cells and normal cells respond to osmotic pressure changes differently remains unclear. Here, we subjected cancer and normal cells to osmotic shocks and compared their volume and traction force changes. Under hypotonic conditions, cancer cells recovered their volume and forces much more slowly than normal cells, although both cell types responded similarly to hypertonic shock. We found that actin-based cortical tension controlled the recovery speed; whereas myosin-mediated contractility tuned the volume change extent. Substrate stiffness also influenced the recovery process by altering cytoskeletal constraint. A theoretical model integrating adhesion energy, ion and water transport, and surface tension was developed. The results matched the experimental observations. Our work uncovered the distinct mechanobiological behaviors of cancer cells upon hypotonic shock, providing a mechanical framework for understanding cancer mechanisms that may inform the development of cancer therapeutics.

biophysics↗

In vivo-directed evolution identifies AAV-WM04 as a next-generation vector for potent and durable hearing restoration in DFNB9

Efficient and cell-specific gene delivery to cochlear inner hair cells (IHCs) remains a major challenge for inner ear gene therapy. Here, we identify and characterize a novel AAV2-derived capsid, AAV-WM04, that enables highly efficient and selective IHC transduction at low doses. Using an in vivo-directed evolution strategy, we generated a randomized AAV2 capsid library with 9-amino acid insertions and performed iterative selection in the adult mouse cochlea. Next-generation sequencing revealed enrichment of several variants, among which AAV-WM04 exhibited superior packaging efficiency and pronounced IHC tropism. AAV-WM04 achieved near-complete IHC transduction throughout the cochlear axis in adult mice, outperforming clinically relevant vectors with minimal off-target expression and no detectable ototoxicity. Robust and exclusive IHC transduction was further validated in non-human primates following round window membrane delivery, underscoring translational potential. Therapeutically, AAV-WM04 enabled efficient dual-AAV trans-splicing delivery of the large OTOF gene, resulting in uniform full-length otoferlin expression in IHCs. In a humanized Otof Q829X/Q829X mouse model, AAV-WM04 restored auditory function across a broad frequency range at relatively low doses and achieved durable hearing recovery. Collectively, these findings establish AAV-WM04 as a next-generation IHC-targeted vector with high efficiency, safety, and cross-species applicability for precision gene therapy of hereditary hearing loss.

genetics↗

Automatic Generation of Model Sequences for Complex Regions in Assembly Graphs

Recent developments in genome sequencing and assembly technologies have enabled the automated assembly of vertebrate chromosomes from telomere to telomere. However, for some long, highly similar repeats, genome assemblers may lack sufficient information to unambiguously resolve the sequence, leaving tangles in the assembly graph and gaps in the final assembly. In recently published genomes, such gaps are often closed by manual graph curation, a process that is labor-intensive, error-prone, and sometimes infeasible. This can leave important genomic repeats, such as recently duplicated genes, misassembled or excluded from the final assembly. Here we present the Trivial Tangle Traverser (TTT) algorithm that finds optimized resolutions of assembly graph tangles. TTT uses depth of coverage and read-to-graph alignment information in a two-stage process to identify evidence-based traversals that are consistent with the underlying data. First, sequence multiplicities are estimated through mixed-integer linear programming, after which an Eulerian path is found in the derived multigraph and optimized through a gradient-descent-like approach. We evaluate TTT traversals on the HG002 human reference genome and demonstrate its use to characterize a previously unassembled amplified gene array in the zebra finch genome. AvailabilityTTT is available at https://github.com/marbl/TTT

bioinformatics↗

CDK/mTOR-dependent phosphorylation of UBE2H restrains its charging with ubiquitin and regulates CTLH-dependent degradation

The C-terminal to LisH (CTLH) complex is a modular multi-subunit E3 ligase with diverse biological functions, yet how its overall ubiquitylation activity is tuned remains unclear. Here, we identify CDK- and mTOR-dependent phosphorylation of the cognate E2 enzyme UBE2H as a key regulator of CTLH E3 catalytic capacity. Phosphorylation of two N-terminal serine residues (S3/S5) reduces UBE2H charging with ubiquitin, thereby limiting the pool of active E2 available to CTLH. Mitotic CDK activity inactivates UBE2H during mitosis, whereas mTOR restrains UBE2H charging in interphase to couple CTLH-dependent ubiquitylation to nutrient status. Preventing this phosphorylation maintains UBE2H charging, enhances CTLH-mediated substrate degradation, promotes CTLH subunit turnover, and causes proliferation and mitotic defects. Using hyperactive UBE2H, we identify two additional CTLH substrates, the mitotic kinase NEK9 and Angio-associated migratory cell protein (AAMP) and define a DR-like C-degron recognized by the CTLH subunit MKLN1. These findings reveal how regulation of an E2 enzyme by cell cycle and nutrient signaling pathways dynamically shape CTLH activity.

cell biology↗

Enteric sensory neurons for nutrient detection and gut motility

The enteric nervous system (ENS) orchestrates gastrointestinal reflexes and brain-gut communication via molecularly diverse neurons. Among these, intrinsic primary afferent neurons (IPANs) are essential for detecting luminal nutrients and irritants, yet their molecular identities, sensory properties, and functions remain poorly resolved. Here, we establish a segment-resolved single-cell atlas of the murine ENS, including a comprehensive characterization of the gastric ENS. This resource defines a refined taxonomy of enteric neurons and glia and enabled the development of a genetic toolkit for molecularly defined IPANs. Using chemogenetics and calcium imaging, we discovered that myenteric neurons detect a wide range of nutrients, irritants, and cytokines. Nutrient detection depends on a functional connection between chemosensory epithelial cells and enteric neurons mediated by 5-HT--HTR3 axis. Through optogenetic analysis, we demonstrated segment-specific regulation of gut motility by different IPANs. Our work establishes a genetic and physiological framework for enteric-specific sensory mechanisms.

neuroscience↗