Biology subjects

Chen, R.

Publications and source records attributed to Chen, R..

At least 37 records · Page 2Linked to original sources

bioRxiv2026

Extended Amygdala CRF Projections to Striatal Striosomes Potentiate Dopamine Suppression During Fentanyl Withdrawal

Opioid withdrawal is a powerful negative affective state that promotes continued drug use and relapse, and is often associated with hypodopaminergic states. Although corticotropin-releasing factor (CRF) signaling in the extended amygdala has been strongly implicated in stress and negative affect, how withdrawal-recruited CRF systems suppress dopamine release remains poorly understood. Here, we identify an extended amygdala-striosome-dopamine pathway engaged during fentanyl withdrawal. Naloxone-precipitated fentanyl withdrawal selectively recruited CRF neurons in the central amygdala and bed nucleus of the stria terminalis. These CRF neurons provided monosynaptic input to dorsostriatal medium spiny neurons (MSNs). Because striosomal MSNs are positioned to regulate dopamine release, we next found that CRF enhanced glutamatergic synaptic transmission onto striosomal MSNs, with CRF receptor 1 (CRFR1) signaling required for the postsynaptic strengthening of excitatory transmission. In vivo dopamine photometry further revealed that naloxone-precipitated withdrawal amplified striosome-mediated suppression of dopamine release, and this amplification was prevented by CRFR1 antagonism. Together, these findings reveal a mechanism by which withdrawal-recruited CRF signaling potentiates striosomal control of dopamine release. This extended amygdala-striosome-dopamine pathway may contribute to the hypodopaminergic negative affective state that drives opioid withdrawal and relapse vulnerability. HighlightsO_LIFentanyl withdrawal selectively recruits CeA and BNST CRF neurons C_LIO_LICeA and BNST CRF neurons provide monosynaptic input to striatal MSNs C_LIO_LICRF potentiates glutamatergic transmission onto striosomal MSNs via CRFR1 C_LIO_LICRFR1 signaling amplifies striosome-mediated dopamine suppression during withdrawal C_LI

neuroscience↗

bioRxiv2026

An Integrated muti-omics cell atlas of the human trabecular meshwork and ciliary body

The trabecular meshwork (TM) and ciliary body (CB) regulate aqueous humor dynamics and intraocular pressure (IOP), and TM/Schlemms canal (SC) dysfunction underlies glaucoma. Here, we present a spatially resolved multi-omics atlas of human TM and CB, integrating snRNA-seq, scRNA-seq, and snATAC-seq from over one million cells and nuclei across 112 donors with Xenium spatial transcriptomics. We identified 9 major cell classes and 21 cell types, revealing heterogeneity, including undercharacterized fibroblast and epithelial subpopulations. Spatial mapping supported TM fibroblast zonation and CB epithelial organization. Regulatory analyses identified cell type-specific programs, including OTX/PAX networks in CB epithelium and SMAD3/TGF-{beta} signaling in fibroblasts. Integration with glaucoma loci showed enrichment of non-coding variants in regulatory elements associated with POAG and PACG. Age- and ancestry-associated remodeling revealed divergent fibroblast aging with increased PIEZO1, suggesting impaired outflow and elevated IOP. Together, this high-resolution atlas links cellular, regulatory, and genetic variation to anterior segment function and glaucoma susceptibility.

genomics↗

bioRxiv2026

Systemic interindividual epigenetic variants link periconceptional environment to human fetal development

At rare human genomic regions, DNA methylation states are established in the early embryo and maintained during cellular differentiation, yielding systemic (i.e. not tissue-specific) interindividual epigenetic variation. Previous screens for such correlated regions of systemic interindividual variation (CoRSIVs) were limited to White Americans. Here, we describe the first human CoRSIV screen including self-identified Black and White Americans. We integrate deep whole-genome bisulfite sequencing data for three tissues from each of ten Black and ten White donors in the NIH Genotype-Tissue Expression program. This approach identifies twice as many CoRSIVs among Black than White Americans. Establishment of CoRSIV methylation is sensitive to periconceptional environmental exposures including assisted reproduction, seasonal variation, and famine. CoRSIV-associated genes are enriched for GWAS variants linked to cancer and neurodevelopment. Although only 15% of Black CoRSIVs overlap with those among White individuals, both sets are associated with the same subfamilies of transposable elements. Within multiple cell lines, ranked enrichments of transcription factor binding to Black and White CoRSIVs are exquisitely coordinated and related to genome organization, indicating that CoRSIV methylation states established in the early embryo play an important role in guiding subsequent cellular differentiation.

Molecular Biology↗

bioRxiv2026

Somatic variant detection in normal tissues from single-cell sequencing data

A crucial advantage of single-cell sequencing (SCS) is its ability to identify somatic variants in individual cells, enabling phylogenetic analysis of cellular populations within bulk tissues. While identifying somatic variants in tumor tissues via SCS has become a common practice, doing so in normal tissues remains challenging due to the rarity of somatic variants in normal cells. To evaluate the feasibility of somatic variant calling from widely available single-nucleus RNA-seq (snRNA-seq) and single-nucleus ATAC-seq (snATAC-seq) data, we profiled a Cell-line mix of six HapMap samples prepared by the SMaHT consortium using 10x Genomics 5 snRNA-seq (12k cells with 36k mean reads per cell) and snATAC-seq (11k cells with 14k median high-quality fragments per cell) for variant calling. PacBio long-read whole genome sequencing (WGS) data (109x) generated from individual cell lines were used as ground truth. Two computational tools, Monopogen and SComatic, were used for somatic variant calling from the SCS data. Monopogen achieved single nucleotide variant (SNV) detection accuracies of 93.30% in the snRNA-seq and 99.64% in the snATAC-seq data, both of which outperformed SComatic (74.35% and 94.29%, respectively). Monopogen also consistently detected somatic SNVs at cellular fractions as low as 0.5% (2.54% in snRNA and 0.81% in snATAC) in individual samples. Notably, snATAC-seq exhibited higher genomic coverage breadth and larger number of variants detected than snRNA-seq. While the SCS data have lower overall genome coverage than that of the bulk WGS, the single-cell level variant resolution allows Monopogen to assign variants to their cells of origin with over 80% accuracy in both RNA and ATAC modalities, thereby facilitating studies of clonal evolution and cell-type-specific mutagenesis. Other benchmarking methods were also evaluated (DeepVariant, Cellsnp-lite and Mutect2) for comparison. In conclusion, our study demonstrated the feasibility of performing reliable single-cell somatic mutation calling in a cell-line mixture and discussed the strengths and limitations of current computational methods when applied to normal tissues.

bioinformatics↗

bioRxiv2026

Mechano-Initiated PIEZO1-VEGFR2 Interaction Governs CD34+ Cell Differentiation and Repair in Arteriovenous Fistula

BackgroundEndothelial cell (EC) injury induced by disturbed flow drives neointimal hyperplasia in arteriovenous fistulas (AVFs), where CD34+ cell-mediated repair may be involved. PIEZO1 and VEGFR2 are important mechanosensors with critical role in maintaining endothelial function. However, whether PIEZO1 interacts with VEGFR2 during CD34+ cell differentiation to orchestrate the vascular repair remains unknown. MethodsAVF model was established in several mouse strains. Single cell RNA sequencing was performed for human and mouse samples. Cd34-CreERT2; R26-tdTomato; Piezo1flox/flox mice were used to investigate the effect of Piezo1 deletion on endothelial repair in AVFs. CD34-high human umbilical vein ECs (CD34high HUVECs) was sorted and exposed to different flow patterns to determine the role of shear stress in CD34high cell differentiation. Co-immunoprecipitation, proximal ligation assay and complementary approaches were performed to delineate mechanotransduction initiated by PIEZO1-VEGFR2 interaction. ResultsSingle cell RNA sequencing and immunostaining showed abundant CD34high cells in the vessel wall of AVFs in humans and animal models. Exposure of CD34high HUVECs to different flow patterns showed that laminar shear stress downregulated CD34 while upregulating VE-cadherin and claudin-5 expression. In contrast, oscillatory flow produced the opposite effects, indicating impaired endothelial maturation. PIEZO1 knockdown in CD34high HUVECs attenuated shear stress-induced endothelial marker expression. In Cd34 conditional Piezo1 knockout mouse model of AVF, we observed decreased number of CD34-derived cells, more compact cellular arrangement, and attenuated neointimal hyperplasia. Mechanistically, we found PIEZO1 interacts with VEGFR2, thereby mediating the distinct effects of laminar and oscillatory shear stress on AKT-FoxO1 axis, which critically regulates endothelial marker expression. Furthermore, pharmacological activation of AKT signaling in AVF mouse model enhanced CD34+ cell-mediated endothelial repair and attenuated neointimal hyperplasia. ConclusionPIEZO1-VEGFR2 complex-mediated mechanotransduction plays a key role in regulating CD34+ cell-derived endothelial repair in AVFs via AKT-FoxO1 axis. AKT activation enhances endothelial maturation, thereby attenuating neointimal hyperplasia in AVFs. Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIIn arteriovenous fistulas (AVFs), abnormal shear stress induces endothelial cell injury, and the resulting neointimal hyperplasia is a major cause of anastomotic stenosis. C_LIO_LICD34 cells actively participate in vascular endothelial repair. C_LIO_LIPIEZO1 is a mechanoreceptor mediating endothelial sensing of hemodynamic shear stress, contributing to the maintenance of atheroprotective endothelial phenotype under laminar shear stress, whereas its activation induces pro-inflammatory effects under disturbed shear stress. C_LI What New Information Does This Article Contribute?O_LICD34 cells participate in repairing endothelial injury induced by abnormal shear stress in AVFs. PIEZO1 knockout in CD34+ cells improve endothelial repair and attenuates neointimal hyperplasia in AVF. C_LIO_LILaminar shear stress induces CD34 downregulation and upregulates VE-cadherin and claudin-5 expression in CD34-high human umbilical vein endothelial cells, whereas oscillatory shear stress upregulates CD34 expression and suppresses VE-cadherin and claudin-5 expression. C_LIO_LIMechano-stimuli lead to PIEZO1-VEGFR2 complex formation regulating CD34 cell-mediated endothelial repair through the downstream AKT-FoxO1 axis. C_LI Abnormal hemodynamic shear stress-induced endothelial injury initiates neointimal hyperplasia in AVFs. The present study identifies PIEZO1 as a key mechanosensor that regulates CD34+ cell-derived endothelial repair in response to distinct blood flow patterns. PIEZO1 promotes CD34+ cell differentiation into mature ECs for endothelial repair under laminar shear stress, whereas it disrupts the differentiation of CD34+ cells into mature endothelium under oscillatory shear stress. Mechanistically, a novel shear stress-sensing complex comprising PIEZO1 and VEGFR2 was identified in regulating flow-induced differentiation of CD34+ cells into mature ECs via the AKT-FoxO1 signaling axis, thereby controlling the expression of endothelial maturation markers VE-Cadherin and Claudin-5. These findings define a novel PIEZO1-VEGFR2 mechanotransduction axis in CD34+ cell-mediated endothelial repair and support AKT pathway activation as a potential therapeutic strategy against neointimal hyperplasia in AVFs.

cell biology↗

bioRxiv2026

Metal Coordination Dynamics Governs Selective Epoxidation in Hyoscyamine 6β-Hydroxylase: Integrated Experimental and Computational Insights

Iron(II)- and 2-oxoglutarate-dependent (Fe(II)/2OG) enzymes catalyze a wide range of C-H bond activation and functionalization reactions and play essential roles in biosynthesis and metabolic regulation. Despite extensive mechanistic studies, the principles governing selectivity between canonical hydroxylation and alternative transformations remain incompletely understood. Here, we investigate the catalytic mechanism of hyoscyamine 6{beta}-hydroxylase (H6H), a Fe(II)/2OG-dependent oxygenase that sequentially catalyzes the 6{beta}-hydroxylation of hyoscyamine followed by 6,7-exo-epoxidation of 6{beta}-hydroxyhyoscyamine to generate scopolamine. Combined molecular dynamics and QM/MM calculations reveal that an inline Fe(IV)-oxo intermediate initiates hydrogen atom abstraction from the substrate C7 position. The resulting Fe(III)-OH species subsequently deprotonates the substrate hydroxyl group in a process coupled to substrate coordination to the iron center and an in-line-to-off-line rearrangement of the Fe(III)-OH moiety. This coordination dynamics machinery is further supported by the observed chlorination reactivity on the same substrate. Importantly, this coordination switch favors epoxide formation over hydroxyl rebound, thereby directing the reaction toward selective epoxidation. Further computational analysis of the L290F variant demonstrates that steric constraints imposed by L290 are essential for suppressing hydroxylation, revealing a bidirectional regulatory mechanism governing epoxidation/hydroxylation selectivity. Whereas iron coordination dynamics promote epoxidation reactivity, precise substrate positioning and protein-derived steric effects suppress the competing hydroxylation pathway. These findings are consistent with available experimental observations and establish metal coordination dynamics as a key determinant of selective C-H functionalization in Fe(II)/2OG enzymes.

biochemistry↗

bioRxiv2026

WTAP-mediated epitranscriptomic program in alveolar macrophages confers prolonged protection against postinfluenza bacterial pneumonia

Secondary bacterial infections remain an intractable problem of seasonal influenza, primarily due to the depletion and defunctionalization of alveolar macrophages (AMs). Here, we described that N6-methyladenosine (m6A), the most prevalent RNA modification in eukaryotes, critically orchestrates trained immunity (TRIM) establishment in AMs. Influenza A virus (IAV)-trained AMs maintained low Wilms tumor 1-associated protein (WTAP) expression and reduced global m6A deposition for over two months. Mechanistically, this IAV-induced m6A decrease promotes TRIM by enhancing the RNA stability of phagocytic and metabolic genes, thereby boosting antibacterial function. Mimicking this m6A reduction pharmacologically or genetically recapitulates the IAV-trained TRIM phenotype, which improves phagocytosis and protects mice from secondary infection. Clinically, elevated WTAP in AMs correlates with impaired phagocytosis and disease severity in COVID-19 and COPD. These findings for the first time unveil how respiratory virus infection shapes AM TRIM via epitranscriptomic reprogramming, and offer prospective strategies for the prevention and treatment of post-viral bacterial complications.

immunology↗

bioRxiv2026

Decoding Immune Reconstitution Failure in People Living with HIV through Single-cell Genomics

Immune non-responders (INRs), a subset of people living with HIV (PLWH), fail to achieve full immune reconstitution and remain at increased risk of morbidity, mortality, and non-AIDS-related illnesses. As the mechanisms underlying this impaired immune recovery remain poorly understood, we performed single-cell multi-omics profiling on peripheral blood mononuclear cells from 43 INRs, 47 immune responders and 53 healthy donors. Our dataset comprises 2,744,009 transcriptomes and 1,226,658 chromatin-accessibility profiles across 58 identified immune cell types. INRs exhibited markedly elevated inflammatory signaling, increased apoptotic activity, and dysregulation of immune-activating ligand-receptor interactions. Additionally, we identified 2,996 interaction cis-eGenes and 5,938 cis-caPeaks, and validated key cell type-specific cis-xQTL effects associated with immune reconstitution failure. Furthermore, we identified 3,551 sc-eQTLs and 872 cell-state interaction eQTLs (ieQTLs) in CD4+ T cells. A genotype-specific upregulation of OAS3 in INRs, likely regulated by STAT1, was identified based on these results. We developed scPRISM (single cell Predictive Reconstitution Immune Status Model), a multi-modal framework that integrates scRNA-seq and scATAC-seq data to perform the dual tasks of differentiating disease states and predicting gene expression from chromatin accessibility, thereby deciphering the cell type-specific cis-regulatory basis of the disease. Our study delineates the transcriptional and epigenomic landscape of immune dysregulation in INRs and provides new genetic insights into HIV-associated immune reconstitution failure. These findings offer a foundation for developing biomarkers and precision therapies to restore immune function in PLWH.

genetics↗

bioRxiv2026

Growth-dependent tRNA Reprogramming and Codon Bias Link Translation to Metabolic State in Enterococcus faecalis

Enterococcus faecalis is a Gram-positive commensal bacterium of the human gut microbiome and an opportunistic pathogen responsible for many hospital-acquired infections. Despite the clinical importance of E. faecalis, how gene and protein expression are coordinated with growth remains poorly defined. Here, we profiled transcript, protein, and tRNA pool dynamics across distinct phases of E. faecalis growth. Differences in protein abundance and corresponding mRNA levels suggested growth phase-dependent posttranscriptional regulation. Growth-associated genes exhibited biased synonymous codon usage, with ribosomal and glycolytic proteins enriched in low-abundance codons read by queuosine-modifiable tRNAs. Analysis of tRNA modification and tRNA isoacceptor abundance revealed growth phase-dependent changes, particularly in anticodon stem loop modifications that influence synonymous codon translation. Changes in queuosine levels preceded shifts in ribosomal proteins, suggesting a contribution to codon-biased translation. Collectively, these findings reveal growth phase-associated remodeling of the E. faecalis tRNA pool and support a model in which queuosine-dependent translational reprogramming shapes protein expression during bacterial growth. IMPORTANCEEnterococcus faecalis is a common cause of hospital-acquired infections. Despite its clinical importance, a comprehensive understanding of the organisms physiology and adaptation to environmental changes remains incomplete. Here, we characterized protein, transcript, and tRNA dynamics across bacterial growth phases, uncovering a role for post-transcriptional regulation marked by tRNA reprogramming and biased synonymous codon usage. These findings enhance our understanding of E. faecalis growth and support a model of translational reprogramming therein.

microbiology↗

bioRxiv2026

The discovery of missing taxane C13α-O-deacetylases re-delineates the biosynthetic pathway of paclitaxel

The prevalence of naturally occurring C13-acetoxy taxanes, together with the presence of a native C13-acetyltransferase in yew trees, suggests that the natural biosynthetic pathway for paclitaxel may involve a cryptic C13-O-deacetylation step. However, whether a putative taxane C13-O-deacetylase (T13dA) acts in the pathway of paclitaxel biosynthesis remains elusive. Herein, we functionally characterized two novel taxane C13-O-deacetylases (T13dA1 and T13dA2) from Taxus x media cell cultures, providing experimental evidence for the molecular and biochemical plausibility of C13-O-deacetylation in paclitaxel biosynthesis in Taxus species. Furthermore, T7dA1, a novel taxane C7{beta}-O-deacetylase with higher activity than the reported T7dA was discovered and characterized here. Notably, we reconstituted a new 19-gene pathway enabled by the integration of a C13-O-acetylation-deacetylation module for the de novo biosynthesis of baccatin III in Nicotiana benthamiana leaves, reaching a yield of 71{square} g{square} g-1 DW, much higher than that obtained from the 17{square} gene pathway lacking this module. These findings not only demonstrate the functional importance of the C13-O-acetylation-deacetylation module as a branch within the paclitaxel biosynthetic network, but also expand the multi-branched taxane metabolic network in Taxus and provide novel enzymatic tools and engineering strategies to facilitate heterologous pathway reconstitution and efficient paclitaxel production.

biochemistry↗

bioRxiv2026

Global Acetylome Profiling Reveals Extensive Lysine Acetylation in Acinetobacter baumannii Bacteriophage Proteins

Post-translational modifications (PTMs) are increasingly recognized as potential regulators of bacteriophage-host interactions, yet their functions remain largely undefined. Here, we present the first proteome-wide characterization of lysine acetylation in a bacteriophage, using Acinetobacter baumannii myovirus vB_AbaM_DLP3 as a model to investigate host-imposed modification during infection. An optimized proteomic workflow that eliminates chemical artifacts and improves peptide identification accuracy enabled detection of 86 acetylated proteins, representing nearly one-third of the DLP3 proteome. Comparative analysis of purified virions and infected host cells revealed distinct acetylation profiles, consistent with host-driven, transient modifications that are removed or lost after lysis. Functional annotation showed that acetylation predominantly targets proteins involved in DNA replication, genome packaging, and structural assembly. Structural modeling of the major capsid and replication-associated proteins demonstrated that acetylation neutralizes positive surface charges, potentially weakening DNA binding and intercapsomer interactions critical for replication and capsid cohesion. Together, these findings establish lysine acetylation as a widespread and dynamic feature of phage infection and identify host-imposed acetylation as a potential regulatory mechanism that modulates phage replication, assembly, and infectivity. This work expands the molecular framework of phage-host interactions, providing a foundation for future studies aimed at understanding how bacterial PTMs influence phage function and for engineering phages resistant to host-mediated inhibition. ImportanceBacteriophages are being developed as alternatives to antibiotics, yet little is known about how bacterial hosts chemically modify phage proteins during infection. This study reveals that A. baumannii imposes extensive lysine acetylation on its infecting phage DLP3, affecting proteins involved in DNA replication and structural assembly. By demonstrating that acetylation neutralizes positive surface charges and is largely absent after phage release, this work identifies host-driven acetylation as a previously unrecognized, reversible mechanism that may influence phage infectivity. Understanding how bacteria use post-translational modifications to interfere with phage function provides new insight into phage-host molecular interactions and informs strategies for engineering therapeutic phages resistant to host-imposed inhibition.

microbiology↗

bioRxiv2026

Task-induced topological and geometrical changes in whole-brain dynamics predict cognitive individual differences

Across the last three decades, functional magnetic resonance imaging (fMRI) research - through both resting-state (rsfMRI) and task-based (tfMRI) studies - has greatly advanced our understanding regarding the neural basis of cognition. Yet the mechanistic relationship between rsfMRI and tfMRI is still poorly understood. In particular, it remains unclear how and why the brain activation patterns observed during the resting state are linked to cognitive functioning and individual differences present during task performance. Here, we test a unifying computational account which postulates that task contexts modulate the nonlinear attractor landscape and associated dynamical properties of the brain present under resting conditions, and further that the nature of this modulation is impacted by meaningful cognitive individual differences. To test this account, we develop a joint rsfMRI-tfMRI modeling and analysis framework called Mesoscale Individualized NeuroDynamics with eXogenous inputs (MINDy-X) and apply it to resting and N-back working memory task data from the Human Connectome Project. We first validated that the joint model can simulate and predict both rsfMRI and tfMRI data accurately, consistent with a common underlying dynamical system. Analyses of this joint model revealed that task-related modulation bifurcated the predominantly multistable attractor dynamics present during the resting state towards a predominantly monostable dynamics observed during N-back task states. This topological shift was also accompanied by a geometric reconfiguration, with the task state characterized by an enrichment of dynamical attractor "motifs" clustered around the frontoparietal (FPN) and default mode (DMN) networks. Task-related modulations of this attractor landscape were further subject to clear individual differences, such that individuals who did not exhibit a shift in attractor topology were more error-prone and less cautious in responding, while closer geometric proximity to the FPN and DMN motifs explained additional aspects of task performance. N-back behavior was best characterized by the combination of topological and geometric properties present in both task and rest states, suggesting that they each account for unique aspects of individual variability. The current work supports a novel computational framework for understanding the whole-brain neural activity patterns observed during rsfMRI and tfMRI as reflecting different states within a common non-linear dynamical system. This framework provides a new vocabulary for characterizing cognitive functioning in terms of the unique geometric and topological configuration of the associated attractor landscapes, with the potential for wide application in many domains of basic and clinical neuroscience research.

neuroscience↗

bioRxiv2026

Targeting ALA3 with propiconazole regulates plant growth and enables discovery of promising inhibitor leads

Propiconazole (PCZ) is widely misused growth regulator in leafy Brassica vegetables. Developing green strategies for managing plant architecture has become an urgent agricultural priority. Here, we identified from a membrane-protein-defective yeast library a P4-ATP phospholipid flippase, aminophospholipid ATPase 3 (ALA3), as a target sensitive to PCZ. ALA3 exhibits high binding affinity for PCZ, which inhibits its ATPase activity. Knockdown of ALA3 rendered yeast, Arabidopsis, and Brassica rapa less sensitive to PCZ and conferred a growth-inhibited phenotype. This dwarfing phenotype is mediated through the interaction between ALA3 and CYP51G1 that jointly acts within the brassinosteroid regulatory pathway. Furthermore, we identified lead compounds A01 and A15 as ALA3-targeting agents, and compared to PCZ, they display superior binding affinity and reduced toxicity. Our work establishes ALA3 as a key mediator of PCZ-induced dwarfism and provides dual strategies--creating promising varieties through gene editing and developing targeted green pesticides--to reduce PCZ use. TeaserTargeting ALA3 reduces PCZ use through gene-edited varieties and green pesticides.

plant biology↗

bioRxiv2026

The BraALA3 Homologs Mediate Propiconazole-Modulated Plant Growth in flowering Chinese cabbage

In agriculture, propiconazole (PCZ) controls excessive growth in flowering Chinese cabbage but poses dietary safety risks due to residue accumulation. Therefore, identifying novel PCZ targets and breeding PCZ-free cultivars is critical for the safe production of flowering Chinese cabbage. Here, we identified three P4-ATPase flippase homologs aminophospholipid ATPase 3 (BraALA3a/b/c) in flowering Chinese cabbage that function as sensitive targets for PCZ. These proteins exhibit high binding affinity for PCZ, which directly inhibits their ATPase activity. Overexpression of the BraALA3 homologs enhanced plant growth and increased sensitivity to PCZ, whereas knockdown led to dwarfism and reduced sensitivity. Based on these findings, we identified editable active sites via protoplast-based screening. Genetic transformation of one such site yielded BraALA3a/braala3aK200T mutant lines, which displayed a dwarf and compact architecture. These findings provide a precise molecular target for developing PCZ-free germplasm in flowering Chinese cabbage through gene editing.

plant biology↗

bioRxiv2026

Site-specific O-glycans influence lacritin structure and multimerization in tears

Lacritin is an abundantly expressed glycoprotein in tear fluid and plays key roles in immune response, tear secretion, and bacterial killing. These biological functions are tightly regulated through several biochemical mechanisms including multimerization, proteolysis, and alternative splicing, especially within its C-terminal domain. Given its critical role at the ocular surface, lacritin is currently under investigation as a diagnostic biomarker and therapeutic candidate for dry eye disease (DED). However, despite over three decades since its initial discovery, the functional significance of the O-glycans that comprise more than 50% of its molecular weight remain largely unknown. To address this gap, we leveraged mass spectrometry (MS)-based glycoproteomics and molecular dynamics (MD) to explore the structural role of site-specific O-glycans on C-terminal lacritin. In doing do, we identified distinct glycosylation profiles between monomeric and multimeric lacritin, particularly at glycosites located near crosslinking residues (Lys101 and Lys104) that modulate multimer formation. Building on our glycoproteomics data, we performed MD simulations on monomer and multimer glycoforms and revealed that O-glycans participate in intra-glycan-protein interactions, thereby affecting the conformational flexibility of lacritin and the spatial arrangement of Lys101 and Lys104. Finally, we quantified the solvent-accessible surface area (SASA) of Lys101 and Lys104, highlighting that proximal O-glycosylation is predicted to affect the propensity of these residues to participate in crosslinking. Taken together, these findings underscore a central role for lacritin O-glycans in affecting structural topology with implications for its downstream biological activity.

biophysics↗

bioRxiv2026

Hyperactive STAT1 Promotes T Follicular Helper Type 1 Cell Differentiation to Trigger Autoimmunity

ABSTRACTSHeterozygous gain-of-function (GOF) mutations in signal transducer and activator of transcription 1 (STAT1) cause an inborn error of immunity characterized by immune dysregulation, recurrent infections and various autoimmune manifestations. However, the precise pathogenic mechanism by which STAT1 GOF contributes to autoimmunity remains elusive. In our cohort, STAT1-GOF patients exhibit biased circulating follicular helper T (cTfh) populations with CXCR3+ Tfh1-like features. Using a Stat1 GOF mouse model that spontaneously developed autoimmunity, we found that overactivated STAT1 promotes Tfh differentiation and disrupted T cell-dependent humoral responses with skewed immunoglobulin class switching towards IgG2. Furthermore, STAT1 GOF directly targets to Tfh and Th1 cell signature genes and thereby drives the development of Tfh1 cells with excessive IFN-{gamma} production, which implicated in autoantibody production and the development of autoimmunity. Notably, IFN-{gamma} neutralization significantly alleviated autoimmune cellular responses and autoantibody levels in mutant mice, highlighting IFN-{gamma} blockade as a promising targeted therapy for the STAT1-GOF patients with autoimmunity. Our findings suggest that proper regulation of STAT1 activity within a reasonable magnitude is crucial for ensuring optimal host-protective humoral immunity. One-sentence summaryOveractivated STAT1 promotes Tfh1 differentiation to drive autoimmunity.

immunology↗

bioRxiv2026

Sustained exposure to CAR-T cell secretome impairs human Hematopoietic Stem Cell function and is reversible by dual TNFα-IFNγ blockade

Prolonged cytopenias are a frequent complication of chimeric antigen receptor (CAR) T-cell therapies and are associated with increased infection risk and non-relapse mortality. Although inflammatory cytokines released during CAR-T cell activation have been implicated in immune effector cell-associated hematotoxicity (ICAHT), their direct effects on human hematopoietic stem and progenitor cells (HSPCs) function remains incompletely understood. Here, we established a reductionist model of CAR-T-associated hematotoxicity using conditioned media (CM) derived from activated CD19 CAR-T cells. Sustained exposure of human HSPCs to CAR-T-derived inflammatory secretome impaired HSPC expansion and reduced long-term repopulating capacity in xenotransplantation assays. In contrast, short-term exposure did not abrogate HSPC function, indicating that brief inflammatory signals can initiate durable reprogramming events, with functional consequences emerging during subsequent proliferative expansion. Mechanistically, CAR-T CM induced IFN{gamma}- and TNF-responsive transcriptional programs in HSPCs and promoted inflammatory myeloid skewing without evidence of apoptosis-dependent stem cell loss. Combined inhibition of IFN{gamma} and TNF restored HSPC expansion, normalized lineage output, reversed inflammatory transcriptional signatures, and rescued in vivo repopulating capacity without impairing CAR-T cytotoxic activity. These findings demonstrate that CAR-T-derived inflammatory signaling can directly impair human HSC function and identify dual TNF/ IFN{gamma} blockade as a potential strategy to mitigate CAR-T-associated hematotoxicity while preserving antitumor efficacy.

cell biology↗

bioRxiv2026

Med12 and Med13 prevent tumorigenic dedifferentiation of intermediate neural progenitors and premature loss of neural stem cells

Med12 and Med13 are components of the kinase module of the mediator complex. Mutations of Med12 and Med13 have been associated with neurodevelopmental disorders and various cancers. However, their functions in neural development are not well understood. Here we show that in the developing Drosophila brain, Med12 and Med13 are required to prevent tumorigenic dedifferentiation of intermediate neural progenitors (INPs) and maintain neural stem cell (NSC) self-renewal. We further demonstrate that Med12 and Med13 prevent INP dedifferentiation by coordinating with a subset of core mediator complex subunits to mediate the activation of genes required for INP fate commitment. In contrast, during the maintenance of NSC self-renewal, Med12 and Med13 antagonize the function of a different subset of core mediator complex subunits. Together, our findings reveal that Med12 and Med13 perform two distinct functions in neural progenitors by coordinating with one subset of core mediator complex subunits while antagonizing another. HighlightsO_LILoss of Med12 and Med13 causes dedifferentiation of intermediate neural progenitors C_LIO_LIMed12 and Med13 mediate the activation of target genes of PntP1 C_LIO_LILoss of Med12 and Med13 leads to premature loss of neural stem cells C_LIO_LIMed12 and Med13 act with one subset of core mediator subunits but oppose another C_LI eTOC blurbZhu and his colleagues show that Med12 and Med13 promote cell fate commitment of intermediate neural progenitor cells and self-renewal of neural stem cells. Med12 and Med13 perform these two distinct functions by coordinating with one subset of core mediator complex subunits while opposing another to regulate the expression of different target genes.

developmental biology↗