Biology subjects

An, S. S.

Publications and source records attributed to An, S. S..

4 recordsLinked to original sources

bioRxiv2026

A regulatory TRIF/IL-1R1 axis controls T-dependent IgA production in the intestines

Mucosal IgA is critical for controlling the microbiota and preventing pathogenic infection of the epithelium. The innate signals that regulate the generation of IgA remain poorly defined. Here, we identified TRIF and IL-1R1 as immune checkpoints for intestinal IgA production. In the absence of infection, Trif-/- and Il1r1-/- mice exhibited markedly elevated stool IgA and IgA-bound commensals. We show that IL-1R1 restricts IgA class-switching in a B cell-intrinsic manner, while TRIF acts extrinsically of B cells and shapes the Peyers patch microenvironment. Loss of either Trif or Il1r1 enhanced retinoic acid metabolism and allowed premature Ccnd3 upregulation in naive B cells, favoring both IgA class-switching and differentiation into germinal center B cells. During oral vaccination, the absence or blockade of the TRIF/IL-1R1 pathway increased antigen-specific IgA production without affecting seric antigen-specific IgG levels. These findings unveil novel and local signaling targets to promote robust antigen-specific mucosal immunity.

immunology↗

bioRxiv2026

Wasf1 deletion attenuates tau hyperphosphorylation, microglial state transition, and cognitive deficits in P301S tau mice

We previously reported that WAVE1, a major activator of Arp2/3 complex-mediated actin polymerization, is downregulated in postmortem brains of Alzheimers disease (AD) and that WAVE1 regulates amyloid precursor protein trafficking and amyloid-{beta} production. However, its role in tau pathology remains unknown. Here, we demonstrate that WAVE1 activity is suppressed in P301S tau mice through elevated inhibitory phosphorylation. Strikingly, WAVE1 gene (Wasf1) knockout in P301S tau mice significantly reduces tau hyperphosphorylation and improves cognition, suggesting a compensatory role for WAVE1 suppression in tau pathogenesis. Single-nucleus RNA sequencing reveals that Wasf1 deletion in P301S tau mice reverses microglial state transitions, with minimal impact on other brain cell types. Wasf1 mRNA is highly translated in microglia in non-Tg mice, while its expression is downregulated in P301S tau mice. Wasf1 knockdown in BV2 microglia cells enhances the degradation of engulfed tau fibrils, indicating WAVE1 as an endogenous regulator of microglial function. Additionally, CellChat analysis indicates that Wasf1 deletion alters microglial autocrine signaling and their interactions with other cell types in P301S tau mice. These findings, taken together, suggest that Wasf1 deletion restores homeostatic microglial function, mitigates tau pathology, and alleviates cognitive deficits, highlighting WAVE1 as a potential therapeutic target for tauopathy-related dementias.

neuroscience↗

bioRxiv2022

Cells in the Polyaneuploid Cancer Cell (PACC) state have increased metastatic potential

Although metastasis is the leading cause of cancer deaths, it is quite rare at the cellular level. Only a rare subset of cancer cells ([~]1 in 1.5 billion) can complete the entire metastatic cascade: invasion, intravasation, survival in the circulation, extravasation, and colonization (i.e. are metastasis competent). We propose that cells engaging a Polyaneuploid Cancer Cell (PACC) phenotype are metastasis competent. PACCs are enlarged, non-dividing cells with increased genomic content that form in response to stress. Single-cell tracking using time-lapse microscopy reveals that PACCs are more motile than nonPACCs. Additionally, PACCs exhibit increased capacity for environment-sensing and directional migration in chemotactic environments, predicting successful invasion. Magnetic Twisting Cytometry and Atomic Force Microscopy reveal that cells in the PACC state display hyper-elastic properties like increased peripheral deformability and maintained peri-nuclear cortical integrity that predict successful intravasation and extravasation. Furthermore, four orthogonal methods reveal that PACCs have increased expression of Vimentin, a known hyper-elastic biomolecule. Lastly, anoikis-resistance assays and detection of PACCs in the blood of a patient with metastatic castrate-resistant prostate cancer using a selection- free circulating tumor cell detection platform reveal that PACCs are capable of surviving in the circulation. Taken together with the knowledge that PACCs are capable of eventual depolyploidization and progeny formation (as a potential route to colonization), these data support PACCs as candidate metastasis-competent cells worthy of further analysis.

cancer biology↗

bioRxiv2020

PGC1/PPAR Drive Cardiomyocyte Maturation through Regulation of Yap1 and SF3B2

Cardiomyocytes undergo significant levels of structural and functional changes after birth--fundamental processes essential for the heart to produce the volume and contractility to pump blood to the growing body. However, due to the challenges in isolating single postnatal/adult myocytes, how individual newborn cardiomyocytes acquire multiple aspects of mature phenotypes remains poorly understood. Here we implemented large-particle sorting and analyzed single myocytes from neonatal to adult hearts. Early myocytes exhibited a wide-ranging transcriptomic and size heterogeneity, maintained until adulthood with a continuous transcriptomic shift. Gene regulatory network analysis followed by mosaic gene deletion revealed that peroxisome proliferator-activated receptor coactivator-1 signaling--activated in vivo but inactive in pluripotent stem cell-derived cardiomyocytes--mediates the shift. The signaling regulated key aspects of cardiomyocyte maturation simultaneously through previously unrecognized regulators, including Yap1 and SF3B2. Our study provides a single-cell roadmap of heterogeneous transitions coupled to cellular features and unveils a multifaceted regulator controlling cardiomyocyte maturation. Significance StatementHow the individual single myocytes achieve full maturity remains a black box, largely due to the challenges with the isolation of single mature myocytes. Understanding this process is particularly important as the immaturity and early developmental arrest of pluripotent stem cell-derived myocytes has emerged a major concern in the field. Here we present the first study of high-quality single-cell transcriptomic analysis of cardiac muscle cells from neonatal to adult hearts. We identify a central transcription factor and its novel targets that control key aspects of myocyte maturation, including cellular hypertrophy, contractility, and mitochondrial activity.

developmental biology↗