Biology subjects

Xun, J.

Publications and source records attributed to Xun, J..

5 recordsLinked to original sources

bioRxiv2026

SOLAR Mediates Lysosomal Membrane Repair and Redox Defense

Lysosomal damage is increasingly recognized as a hallmark of aging. Understanding lysosomal quality control may open new therapeutic strategies to enhance lysosomal resilience. Here, we identify SOLAR (SQSTM1/p62 Oligomer-mediated Lysosomal Antioxidant Defense And Membrane Repair), a lysosomal quality control pathway that links CASM (conjugation of ATG8 to single membranes) to p62-driven membrane repair and redox signaling. In this pathway, CASM, but not macroautophagy, recruited p62 to damaged lysosomes. Efficient lysosomal recruitment of p62 required its ATG8-binding and self-oligomerizing domains, enabling p62 assemblies to promote membrane repair. p62 mutations associated with neurodegeneration interfered with p62 recruitment and compromised lysosomal repair. Besides membrane repair, the SOLAR pathway also activated the p62-KEAP1-NRF2 redox signaling axis, driving transcriptional upregulation of antioxidative genes and cholesterol biosynthesis. By integrating membrane repair and redox defense, SOLAR establishes a coordinated lysosomal quality control pathway with implications for aging and degenerative disease.

cell biology↗

bioRxiv2025

An Immuno-Linguistic Transformer for Multi-Scale Modeling of T-Cell Spatiotemporal Dynamics

Understanding the spatiotemporal dynamics of T-cell clones is a critical challenge in immunology and immunotherapy, with direct implications for cancer treatment and vaccine design. While Large Language Models (LLMs) have demonstrated immense power in decoding complex sequential data, their application to the "language of immunity" remains nascent. Existing computational models often struggle to capture the hierarchical, multi-scale nature of immune responses and fail to model biologically plausible system perturbations. To bridge this gap, we propose the Immuno-Linguistic Spatiotemporal Transformer (ILST), a self-supervised framework inspired by LLM architectures. Our framework introduces two key innovations: a Biologically-Informed Perturbation (BIP) module that simulates systemic events (e.g., infection or therapy) by respecting the functional importance of key T-cell clones, and a Hierarchical Tissue-Scale Fusion (HTF) module that uses attention to dynamically weigh and combine representations from cellular, tissue, and systemic levels. We validate our model on several public graph datasets, which serve as effective proxies for complex biological networks with varying degrees of heterogeneity. ILST achieves consistently strong results in predicting node states. Notably, it significantly enhances performance on heterogeneous (disassortative) graphs, demonstrating its potential for robustly modeling T-cell dynamics in complex microenvironments like tumors.

bioinformatics↗

bioRxiv2025

FDA-approved drug repurposing in zebrafish identifies thyroid hormone and other compounds as potential antithrombotics

Venous thromboembolism (VTE) is a highly prevalent medical condition with limited therapeutic options and an incomplete understanding of its acquired and inherited subtypes. The zebrafish is a model with the benefits of external development, fecundity, optical transparency, and hemostasis that demonstrates conservation with mammals. We utilized zebrafish as a phenotypic screening tool to identify novel therapeutic options for preventing VTE. A library of FDA-approved compounds was screened for suppression of acquired (elevated estrogen) and spontaneous (protein C deficiency) thrombosis. We found that thyroid hormone, receptor tyrosine kinase (RTK) inhibitors, and proton-pump inhibitors (PPIs) effectively modulated levels of thrombosis, particularly in the estrogen-induced model. These also showed a more favorable hemostatic profile than standard therapies, suggesting alternative mechanisms. Genome editing of thyroid hormone receptor proved that thyroid hormone action is on target. A retrospective electronic health record (EHR) analysis found that thyroid-hormone prescriptions in hormonal contraceptive users correlated with a higher VTE risk, potentially limiting direct repurposing but highlighting thyroid signaling as a pathway involved in estrogen-induced thrombosis. Together, these data identify several drug classes that can be tailored to specific subtypes of VTE and help elucidate distinct pathways driving thrombosis.

pharmacology and toxicology↗

bioRxiv2023

A conserved ion channel function of STING mediates non-canonical autophagy and cell death

The cGAS/STING pathway triggers inflammation in response to diverse cellular stresses such as infection, cellular damage, senescence, normal aging, and age-related disease. Besides inflammation, STING also triggers non-canonical autophagy and cell death, the former of which requires the proton pump V-ATPase- mediated LC3 lipidation to single membrane STING vesicles. V-ATPase is known to sense organelle de- acidification in other contexts and recruits the ATG16L1 complex for direct conjugation of LC3/ATG8 to single membranes (CASM). However, it is unclear how STING activates V-ATPase for non-canonical autophagy. Here we report that upon STING activation, the transmembrane domain (TMD) of STING significantly reorganizes and forms an electron-sparse pore in the center. Cellular imaging and in vitro ion flux assays revealed that STING is critical for proton efflux and pH neutralization of Golgi-derived STING vesicles. A chemical ligand of STING, C53, which binds to and blocks the channel of STING strongly inhibited STING-mediated proton flux in vitro and vesicular de-acidification in cells. C53 also abolished STING-dependent LC3 lipidation and cell death. Thus, the ion channel function of STING activates non-canonical autophagy and cell death through vesicle de-acidification.

biochemistry↗

bioRxiv2022

ASGR1 is a candidate receptor for SARS-CoV-2 that promotes infection of liver cells

Backgroud & AimsCurrently, the COVID-19 pandemic, caused by SARS-CoV-2 infection, represents a serious public health problem worldwide. Although it has been shown that ACE2 serves as the main receptor for SARS-CoV-2 entry into host cells, studies have shown that ACE2 is expressed at extremely low levels in various tissues, especially in some organs where virus particles have been found, such as the heart and liver. Therefore, these organs potentially express additional SARS-CoV-2 receptors that have not yet been discovered. Methods & ResultsHere, by a genome-wide CRISPR-Cas9 activation library screening, we found that ASGR1 promoted SARS-CoV-2 infection of 293T cells. In Huh-7 and HepG2 cell lines, simultaneous knock out of ACE2 and ASGR1 prevented SARS-CoV-2 pseudovirus infection. In the immortalized THLE-2 hepatocyte cell line and primary liver parenchymal cells, both of which hardly express ACE2, SARS-CoV-2 could successfully establish an infection. After treatment with ASGR1 antibody, the infection rate significantly reduced. This suggests that SARS-CoV-2 infects liver cells mainly through an ASGR1-dependent mechanism. Finally, we also found that the soluble ASGR1 could not only prevent the SARS-CoV-2 pseudovirus, which binds to the ASGR1 receptors, from infecting host liver cells, but also had a protective effect on those expressing ACE2, indicating that administration of soluble ASGR1 protein may represent a new treatment approach. ConclusionsColletively, these findings indicate that ASGR1 is a candidate receptor for SARS-CoV-2 that promotes infection of liver cells. Lay SummaryWe show that ASGR1 is a candidate receptor for SARS-CoV-2 to infect liver cells.

microbiology↗