Biology subjects

Krishnan, J. A.

Publications and source records attributed to Krishnan, J. A..

3 recordsLinked to original sources

bioRxiv2025

Endothelial expression of ZBTB16 protects against cardiac aging

Background and aimAging significantly increases the risk of cardiovascular diseases, characterized by progressive cardiac dysfunction. The vascular niche is crucial for maintaining cardiac homeostasis, yet endothelial cell (EC) impairment during aging remains poorly understood. This study investigates epigenetically regulated mechanisms mediating EC-dependent cardiac aging and identifies a critical role of Zinc finger and BTB domain-containing protein 16 (ZBTB16). MethodsChromatin accessibility (snATAC-seq) and transcriptomic (snRNA-seq) analyses were performed on aged hearts to identify age-related regulatory changes. Functional studies using genetic models, assessed cardiac aging phenotypes. In vitro assays examined EC senescence and secretory profiles, while co-culture experiments analyzed the impact of ZBTB16-deficient EC supernatants on fibroblasts, cardiomyocytes, and neurons. Overexpression experiments in vitro and in vivo tested the potential for ZBTB16 to mitigate aging-associated dysfunction. ResultsAged hearts exhibited decreased chromatin accessibility and expression of the transcription factor ZBTB16 in both human and mice. Loss of ZBTB16 in young mice, including Zbtb16 haploinsufficient and endothelial-specific knockout mice, led to premature aging, diastolic dysfunction, and increased secretion of pro-fibrotic and inflammatory factors. Supernatants from ZBTB16-deficient ECs activated fibroblasts, induced cardiomyocyte hypertrophy, and impaired neuronal sprouting. Overexpression of ZBTB16 reversed these effects in senescent ECs and aged mice and reduced diastolic dysfunction. Mechanistic studies identified key downstream targets of ZBTB16, including nuclear receptor-interacting protein 1 (NRIP1). ZBTB16 suppressed NRIP1 expression, limiting fibroblast activation and pro-fibrotic signaling. ConclusionsZBTB16 is a key regulator of endothelial function, maintaining vascular niche homeostasis and mitigating aging-associated cardiac dysfunction. Its loss promotes EC senescence and pro-fibrotic signaling, contributing to diastolic dysfunction. Overexpression of ZBTB16 presents a potential therapeutic strategy for preserving cardiac function during aging. These findings establish a novel role for ZBTB16 in endothelial aging and cardiovascular disease prevention. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/681100v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1a56e2org.highwire.dtl.DTLVardef@13e23fforg.highwire.dtl.DTLVardef@ad681eorg.highwire.dtl.DTLVardef@8eca8b_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2025

Persistent Immune Dysregulation during Post-Acute Sequelae of COVID-19 is Manifested in Antibodies Targeting Envelope and Nucleocapsid Proteins

Post-Acute Sequelae of SARS-CoV-2 infection (PASC) syndrome or "Long COVID" represents a widespread health challenge that necessitates the development of novel diagnostic approaches and targeted therapies that can be readily deployed. Immune dysregulation has been reported as one of the hallmarks of PASC, but the extent of PASC immune dysregulation in patients over time remains unclear. We therefore assessed SARS-CoV-2-specific antibody responses, peripheral immune cell profiles, autoantibody profiles and circulating cytokines for up to 6 months in participants with a SARS-CoV-2 infection who either convalesced or developed PASC. Compared to convalescent, PASC participants with a broad range of PASC phenotypes exhibited persistently elevated IgG titers for SARS-CoV-2 Envelope and Nucleocapsid proteins over the 6 months of study duration. In contrast, the IgG responses to Spike protein were significantly lower in the PASC cohort with predominantly IgG1 and IgG3 class-switched bias. Using CyTOF analysis, we show elevated numbers of circulating T follicular helper cells (cTFH) and mucosa-associated invariant T cells (MAIT), which also correlated with high anti-Envelope IgG titers. Persistent immune activation was accompanied by augmented serum cytokine profiles with LIF, IL-11, Eotaxin-3, and HMGB-1 in PASC participants, who also demonstrated significantly higher rates of autoantibodies. These findings highlight the persistence of immune dysregulation in PASC, underscoring the need to explore targeted therapies addressing viral persistence, dysregulated antibody production, and autoimmunity.

immunology↗

bioRxiv2017

Gene co-expression networks in whole blood implicate multiple interrelated molecular pathways in obese asthma

BackgroundAsthmatic children who develop obesity have poorer outcomes compared to those that do not, including poorer control, more severe symptoms, and greater resistance to standard treatment. Gene expression networks are powerful statistical tools for characterizing the underpinnings of human disease that leverage the putative co-regulatory relationships of genes to infer biological pathways altered in disease states.\n\nObjectiveThe aim of this study was to characterize the biology of childhood asthma complicated by adult obesity.\n\nMethodsWe performed weighted gene co-expression network analysis (WGCNA) of gene expression data in whole blood from 514 adult subjects from the Childhood Asthma Management Program (CAMP). We then performed module preservation and association replication analyses in 418 subjects from two independent asthma cohorts (one pediatric and one adult).\n\nResultsWe identified a multivariate model in which four gene co-expression network modules were associated with incident obesity in CAMP (each P < 0.05). The module memberships were enriched for genes in pathways related to platelets, integrins, extracellular matrix, smooth muscle, NF-{kappa}B signaling, and Hedgehog signaling. The network structures of each of the four obese asthma modules were significantly preserved in both replication cohorts (permutation P = 9.999E-05). The corresponding module gene sets were significantly enriched for differential expression in obese subjects in both replication cohorts (each P < 0.05).\n\nConclusionsOur gene co-expression network profiles thus implicate multiple interrelated pathways in the biology of an important endotype of obese asthma.\n\nKey MessagesO_LIWe hypothesized that individuals with asthma complicated by obesity had distinct blood gene expression signatures.\nC_LIO_LIGene co-expression network analysis implicated several inflammatory biological pathways in one form of obese asthma.\nC_LI\n\nCapsule SummaryThis work addresses a knowledge gap about the molecular relationship between asthma and obesity, suggesting that an endotype of obese asthma, known as asthma complicated by obesity, is underpinned by coherent biological mechanisms.\n\nAbbreviations

genomics↗