bioRxiv Science⌕ Search

Biology subjects

Wang, Y.-Y.

Publications and source records attributed to Wang, Y.-Y..

13 recordsLinked to original sources

Stromal control of sympathetic rewiring in metastatic lymph nodes

Metastatic lymph nodes (LNs) are dynamically remodeled tissues, but this process has been understood mainly in immune and stromal terms. We show that tumor-driven LN remodeling also involves adaptive neural rewiring. In a mouse model of nodal metastasis, sympathetic fibers, but not sensory fibers, progressively expanded during LN remodeling and tracked with metastatic progression. Fibroblastic reticular cells (FRCs) adopted a neuro-supportive program characterized by increased hepatocyte growth factor (HGF) production, while local stromal HGF acted through MET on sympathetic neurons to stimulate neurite outgrowth. Increased substrate stiffness enhanced FRC activation and HGF production, suggesting that mechanical remodeling may reinforce the neuro-supportive stromal state. Inhibition of HGF signaling or ablation of sympathetic innervation reduced LN enlargement and nodal tumor burden. These findings identify neural plasticity as a functional component of the metastatic LN niche and reveal a stromal/mechanical/neural framework that supports metastatic LN progression.

cancer biology↗

Phosphorylation-dependent regulation of Hsp70 chaperones stimulates client recruitment

Molecular chaperones of the Hsp70 family play essential roles in maintaining proteostasis, particularly under conditions of cellular stress. Posttranslational modifications of Hsp70, collectively termed the chaperone code, are emerging as critical regulators of chaperone function, yet their mechanistic contributions remain incompletely understood. Here, we investigate the functional significance of a conserved phosphorylation site in Hsp70, corresponding to serine 326 in yeast Ssa1 and serine 329 in human HSPA8. We demonstrate that DNA double-strand break stress increases cellular reliance on Hsp70 activity in yeast, highlighting a role for chaperones in the DNA damage response. Loss of Ssa1 serine 326 phosphorylation impairs multiple Hsp70-dependent functions, including prion sequestration and glucocorticoid receptor maturation, indicating that this modification is required for optimal chaperone activity. Extending these findings to human cells, we show that the homologous HSPA8 serine 329 residue is necessary for efficient clearance of polyglutamine aggregates. Mechanistically, a phospho-deficient HSPA8-S329A mutant exhibits reduced client-binding capacity. Together, our findings identify a conserved phosphorylation event that enhances Hsp70 function by promoting client engagement, providing new insight into how the chaperone code regulates proteostasis across species.

molecular biology↗

Male-Biased Cyp17a2 Governs Antiviral Sexual Dimorphism in Fish via STING Stabilization and Viral Protein Degradation

Differences in immunity between males and females in living organisms are generally thought to be due to sex hormones and sex chromosomes, and it is often assumed that males have a weaker immune response. Here we report that in fish, males exhibit stronger antiviral immune responses, the male-biased gene cyp17a2 as a critical mediator of this enhanced response. First, we observed that male zebrafish exhibit enhanced antiviral resistance compared to females, and notably, zebrafish lack sex chromosomes. Through transcriptomic screening, we found that cyp17a2 was specifically highly expressed in male fish. Cyp17a2 knockout males were equivalent to wild-type males in terms of sex organs and androgen secretion, but the ability to upregulate IFN as well as antiviral resistance was greatly reduced. Then, Cyp17a2 is identified as a positive IFN regulator which located at endoplasmic reticulum, and specifically interacts with and enhances STING mediated antiviral responses. Mechanistically, Cyp17a2 stabiles STING expression by recruiting the E3 ubiquitin ligase bloodthirsty-related gene family member 32 (btr32), which facilitates K33-linked polyubiquitination. The capacity of IFN induction of Cyp17a2 was abolished when STING is knockdown. Meanwhile, Cyp17a2 also attenuates viral infection directly to strengthen the antiviral capacity as an antiviral protein, Cyp17a2 degrades the spring viremia of carp virus (SVCV) P protein by utilizing USP8 to reduce its K33-linked polyubiquitination. These findings reveal a sex-based regulatory mechanism in teleost antiviral immunity, broadening our understanding of sexual dimorphism in immune responses beyond the conventional roles of sex chromosomes and hormones.

immunology↗

Fish CDK2 recruits Dtx4 to degrade TBK1 through ubiquitination in the antiviral response

Although the classical biological protein cell cycle protein kinase CDK2 has been extensively studied in higher vertebrates, its function in lower vertebrates beyond the regulation of mitosis remains unknown. In this study, we report a distinct mechanism whereby IFN expression is negatively regulated in fish by CDK2. After infection with the spring viremia of carp virus (SVCV), fish CDK2 expression significantly increased in tissues and cells. Moreover, antiviral resistance was improved in cdk2-/- homozygotes, and the antiviral cytokine interferon (IFN) expression was significantly higher. At the cellular level, CDK2 overexpression reduced IFN expression, while cdk2 knockdown increased the ability of cells to produce IFN. Subsequently, it was discovered that fish CDK2 binds and degrades TBK1, resulting in reduced IFN. CDK2 increases the K48-linked ubiquitination of TBK1, causing its degradation, while E3 ubiquitin ligase Dtx4 was found to be involved in this process following the significant enhancement of TBK1 K48-linked ubiquitination. Protein mass spectrometry and immunoblot analysis confirmed that the K567 site on TBK1 is essential for CDK2 to engage with Dtx4 and degrade TBK1; thus, after mutating the K567 site, K48-linked ubiquitination of TBK1 was not enhanced by Dtx4, and TBK1 was not degraded by CDK2. Our data demonstrate that fish CDK2 recruits the E3 ubiquitin ligase Dtx4 to target the K567 site of TBK1 and promote its degradation. These results suggest that CDK2 in lower vertebrates is implicated in a specialized role for antiviral innate immunity.

immunology↗

Mechanism of glucocorticoid receptor activation regulated expression of thrombospondin-1

Objective: Thrombospondin-1 (TSP-1) plays an important role in platelet activation and aggregation and aggravates thrombosis. Chronic stress can cause a variety of diseases, including coagulation disorders, increased thrombosis, atherosclerosis, and a series of cardiovascular and cerebrovascular diseases. However, it is still unknown how chronic stress regulates the expression of TSP-1 after glucocorticoid receptor activation. Approach and Results: rats chronic unpredictable mild stress model was applied and the changes of TSP-1 and microRNAs in plasma were examined. Effects of glucocorticoid receptor activation on human umbilical vein endothelial cells and platelets were observed. Glucocorticoid receptor (GR) activation upregulated the expression of TSP-1 and downregulated the expression of microRNA-1-3p accompanied with increase of phosphorylation of p38 mitogen-activated protein kinase (MAPK) and argonaute-2 (AGO-2). Blockade of p38 MAPK phosphorylation resulted in decrease of phosphorylation level of AGO-2, increase of microRNA-1-3p expression, and decrease of TSP-1 expression. Transfection of AGO-2 Y393F point mutant plasmid, increased microRNA-1-3p expression and decreased TSP-1 expression, transfection of microRNA-1-3p mimic also decreased TSP-1 expression, while transfection of microRNA-1-3p inhibitor increased TSP-1 expression. Finally, GR activation led to an increase in the phosphorylation level of p38 MAPK in platelets and an increase in the level of TSP-1 in the supernatant. Conclusions: our study demonstrates that GR activation in HUVEC stimulates the phosphorylation of p38 MAPK, which in turn promotes the phosphorylation of AGO-2 and inhibits the maturation of microRNA-1-3p, leading to elevated expression of TSP-1, GR activation in platelets leads to the release of TSP-1. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=147 SRC="FIGDIR/small/536820v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@86e8ecorg.highwire.dtl.DTLVardef@126094eorg.highwire.dtl.DTLVardef@2d13c3org.highwire.dtl.DTLVardef@16c79c3_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO HSS: Hydrocortisone sodium succinate C_FIG

pathology↗

A single-cell atlas of the human brain in Alzheimer's disease and its implications for personalized drug repositioning

Alzheimers disease (AD) is a neurodegenerative disease with complex pathophysiology, and AD-dysregulated pathways are inconsistent across different brain regions and patients. Although single-cell RNA sequencing (scRNA-seq) has been performed in different regions of postmortem AD brains, the common and distinct molecular features among different regions remains largely unclear. This hinders the discovery of repurposable and personalized drugs for AD. We combined four scRNA-seq datasets and systematically investigated the common and distinct cellular responses, cell subpopulations, and transcription factors involved in AD. Moreover, we explored the transcriptional heterogeneity of different AD subtypes at the single-cell level. Finally, we conducted individual-based drug repurposing analysis to explore repurposable and personalized drugs. Six major brain cell types were detected after scRNA-seq batch-effect removal and noise cells filtering. Integration with genome-wide association studies (GWAS) summary statistics demonstrated that AD-susceptible genes were mainly enriched with differentially expressed genes (DEGs) in glial cells rather than neuronal cells. While most of DEGs were regulated in opposite directions among different cell types, cell-cell communication analysis revealed several common cellular interaction events involved in neurogenesis, as well as increased cell-cell adhesion. Our comprehensive drug repositioning analysis identified new candidates for AD treatment, including trichostatin, which was predicted to be broadly applicable to different identified AD subtypes, and vorinostat, which was specific for one subtype of AD. In summary, we delineated a cell-specific atlas of the AD transcriptome. Our work illustrated strong cellular heterogeneity in AD for defining AD subtypes. The cell-specific features are important for understanding AD etiology, progression, and drug discovery.

bioinformatics↗

Molecular and structural mechanisms of ZZ domain-mediated cargo recognition by autophagy receptor Nbr1

In selective autophagy, cargo selectivity is determined by autophagy receptors. However, it remains scarcely understood how autophagy receptors recognize specific protein cargos. In the fission yeast Schizosaccharomyces pombe, a selective autophagy pathway termed Nbr1-mediated vacuolar targeting (NVT) employs Nbr1, an autophagy receptor conserved across eukaryotes including humans, to target cytosolic hydrolases into the vacuole. Here, we identify two new NVT cargos, the mannosidase Ams1 and the aminopeptidase Ape4, that bind competitively to the first ZZ domain of Nbr1 (Nbr1-ZZ1). High-resolution cryo-EM analyses reveal how a single ZZ domain recognizes two distinct protein cargos. Nbr1-ZZ1 not only recognizes the N-termini of cargos via a conserved acidic pocket, similar to other characterized ZZ domains, but also engages additional parts of cargos in a cargo-specific manner. Our findings unveil a single-domain bispecific mechanism of autophagy cargo recognition, elucidate its underlying structural basis, and expand the understanding of ZZ domain-mediated protein-protein interactions.

cell biology↗

Histone lysine crotonylation regulates cell-fate determination of neural stem/progenitor cells by activating bivalent promoters

Histone lysine crotonylation (Kcr), an evolutionarily conserved and widely expressed non-acetyl short-chain lysine acylation, plays important roles in transcriptional regulation and disease development. However, its genome-wide distribution, correlation with gene expression, and dynamic changes during developmental processes are largely unknown. In this study, we find that histone Kcr is mainly distributed in active promoters, has a ge-nome-wide positive correlation with transcriptional activity, and regulates transcription of genes participating in metabolism and proliferation. Moreover, elevated histone Kcr activates bivalent promoters to stimulate gene expression in neural stem/progenitor cells (NSPCs), through increasing chromatin openness and recruitment of RNA polymerase II (Pol II). Functionally, these activated genes remodel transcriptome and promote neuronal differentiation. Author summaryOverall, histone Kcr marks active promoters with high gene expression and modifies the local chromatin environment to allow gene activation, which influences neuronal cell fate. It may represent a unique active histone mark involved in neural developmental regulation.

cell biology↗

INSCT: Integrating millions of single cells using batch-aware triplet neural networks

Efficient integration of heterogeneous and increasingly large single cell RNA sequencing (scRNA-seq) data poses a major challenge for analysis and in particular, comprehensive atlasing efforts. Here, we developed a novel deep learning algorithm to overcome batch effects using batch-aware triplet neural networks, called INSCT ("Insight"). Using simulated and real data, we demonstrate that INSCT generates an embedding space which accurately integrates cells across experiments, platforms and species. Our benchmark comparisons with current state-of-the-art scRNA-seq integration methods revealed that INSCT outperforms competing methods in scalability while achieving comparable accuracies. Moreover, using INSCT in semi-supervised mode enables users to classify unlabeled cells by projecting them into a reference collection of annotated cells. To demonstrate scalability, we applied INSCT to integrate more than 2.6 million transcriptomes from four independent studies of mouse brains in less than 1.5 hours using less than 25 gigabytes of memory. This feature empowers researchers to perform atlasing scale data integration in a typical desktop computer environment. INSCT is freely available at https://github.com/lkmklsmn/insct. HighlightsO_LIINSCT accurately integrates multiple scRNA-seq datasets C_LIO_LIINSCT accurately predicts cell types for an independent scRNA-seq dataset C_LIO_LIEfficient deep learning framework enables integration of millions of cells on a personal computer C_LI

bioinformatics↗

ICOS enhances follicular T helper responses and deteriorates the pathogenic process of liver in mice infected with Schistosoma japonicum

BackgroundHumoral immune responses play an important role in mediating liver granulomatous inflammation and fibrosis in schistosomiasis. Follicular helper T (Tfh) cells have a central role in mediating humoral immune responses. Generation of Tfh cells depends on inducible T cell costimulator (ICOS) signaling, but the underlying molecular mechanisms are incompletely understood in pathogenesis of schistosomiasis. Methodology/Principal FindingsWe used a strain of ICOS-transgenic (Tg) mice to test the degrees of liver granulomatous inflammation and fibrosis, the frequency of splenic Tfh cells and soluble egg antigen-specific cytokine responses longitudinally in mice following Schistosoma japonicum (S. japonicum) infection. In comparison with that in wide-type (WT) mice, significantly severer liver granulomatous inflammation and fibrosis and higher mortality were observed in ICOS-Tg mice. Significantly higher frequency of splenic Tfh cells was accompanied by significantly higher levels of Bcl-6 and CXCR5 expression in the livers of ICOS-Tg mice. Furthermore, significantly higher levels of SEA-specific IL-4, IL-6, IL-10, IL-13, IL-17A, IL-21 and TGF-{beta}1 responses, but lower levels of IFN-{gamma} responses were detected in ICOS-Tg mice, which were abrogated by treatment with ICOS blockers in vitro. In addition, significantly higher levels of serum anti-SEA IgG were detected in ICOS-Tg mice. Conclusions/SignificanceThe ICOS-related signaling may promote the pathogenesis of murine schistosomiasis by polarizing Tfh cells, which may be immune check points for the prevention and intervention of schistosomiasis. Author summaryGranulomatous inflammation and fibrosis in the liver are the major pathogenic characteristics of schistosomiasis. ICOS is crucial for the development of Tfh cells, which are the key modulators of B cell activation and humoral immunity. However, the underlying molecular mechanisms are incompletely understood in pathogenesis of schistosomiasis. Here, our results showed that the ICOS over-expression would significantly induce severer liver inflammation and fibrosis, higher frequency of splenic Tfh, higher levels of anti-SEA IgG as well as imbalanced SEA-specific cytokine responses in ICOS-Tg mice. The findings suggested that ICOS signaling may promote the pathogenesis of murine schistosoma-related liver inflammation and fibrosis by polarizing Tfh cells. Potentially, ICOS signaling and Tfh cells may be immune check points for the prevention and intervention of schistosomiasis.

immunology↗

Discovery of a novel coronavirus associated with the recent pneumonia outbreak in humans and its potential bat origin

Since the SARS outbreak 18 years ago, a large number of severe acute respiratory syndrome related coronaviruses (SARSr-CoV) have been discovered in their natural reservoir host, bats1-4. Previous studies indicated that some of those bat SARSr-CoVs have the potential to infect humans5-7. Here we report the identification and characterization of a novel coronavirus (nCoV-2019) which caused an epidemic of acute respiratory syndrome in humans, in Wuhan, China. The epidemic, started from December 12th, 2019, has caused 198 laboratory confirmed infections with three fatal cases by January 20th, 2020. Full-length genome sequences were obtained from five patients at the early stage of the outbreak. They are almost identical to each other and share 79.5% sequence identify to SARS-CoV. Furthermore, it was found that nCoV-2019 is 96% identical at the whole genome level to a bat coronavirus. The pairwise protein sequence analysis of seven conserved non-structural proteins show that this virus belongs to the species of SARSr-CoV. The nCoV-2019 virus was then isolated from the bronchoalveolar lavage fluid of a critically ill patient, which can be neutralized by sera from several patients. Importantly, we have confirmed that this novel CoV uses the same cell entry receptor, ACE2, as SARS-CoV.

microbiology↗

Direct synthesis of EM-visible gold nanoparticles on genetically encoded tags for single-molecule visualization in cells

Single-molecule visualization in cells with genetically encoded tags for electron microscopy (EM) has been a long-awaited but unimplemented tool for cell biologists. Here, we report an approach for directly synthesizing EM-visible gold nanoparticles (AuNPs) on cysteine-rich tags for single-molecule visualization in cells. We first uncovered an auto-nucleation suppression mechanism that allows specific synthesis of AuNPs on isolated cysteine-rich tags. We next exploited this mechanism to develop an approach for single-molecule detection of proteins in prokaryotic cells and achieved an unprecedented labeling efficiency. We then expanded it to more complicated eukaryotic cells and successfully detected the proteins targeted to various organelles, including the membranes of endoplasmic reticulum (ER) and nuclear envelope, ER lumen, nuclear pores, spindle pole bodies, and mitochondrial matrix. Thus, our implementation of genetically encoded tags for EM should allow cell biologists to address an enormous range of biological questions at single-molecule level in diverse cellular ultrastructural contexts without using antibodies.

biophysics↗

Antibody-mediated immobilization of virions in mucus

Antibodies have been shown to hinder the movement of Herpes Simplex Virus (HSV) virions in cervicovaginal mucus (CVM), as well as other viruses in other mucus secretions. However, it has not been possible to directly observe the mechanisms underlying this phenomenon, so the nature of virion-antibody-mucin interactions remain poorly understood. In this work, we analyzed thousands of virion traces from single particle tracking experiments to explicate how antibodies must cooperate to immobilize virions for relatively long time periods. First, using a clustering analysis, we observed a clear separation between two classes of virion behavior: Freely Diffusing and Immobilized. While the proportion of Freely Diffusing virions decreased with antibody concentration, the magnitude of their diffusivity did not, implying an all-or-nothing dichotomy in the pathwise effect of the antibodies. Proceeding under the assumption that all binding events are reversible, we used a novel switch-point detection method to conclude that there are very few, if any, state-switches on the experimental time scale of twenty seconds. To understand this slow state-switching, we analyzed a recently proposed continuous-time Markov chain model for binding kinetics and virion movement. Model analysis implied that virion immobilization requires cooperation by multiple antibodies that are simultaneously bound to the virion and mucin matrix, and that there is an entanglement phenomenon that accelerates antibody-mucin binding when a virion is immobilized. In addition to developing a widely-applicable framework for analyzing multi-state particle behavior, this work substantially enhances our mechanistic understanding of how antibodies can reinforce a mucus barrier against passive invasive species.

immunology↗