Biology subjects

Chelvanambi, S.

Publications and source records attributed to Chelvanambi, S..

4 recordsLinked to original sources

bioRxiv2026

Multiparametric Extracellular Vesicle Profiling Identifies a Distinct Circulating Signature of Bicuspid Aortic Valve Disease

Background: Calcific aortic valve disease (CAVD) resulting in life-threatening aortic stenosis, heart failure and death, develops earlier and progresses more rapidly in patients with bicuspid aortic valves (BAV) than tricuspid aortic valves (TAV), yet the circulating molecular drivers remain poorly understood. Extracellular vesicles (EVs) capture disease-relevant cellular activation and offer a powerful window into a BAV-specific pathophysiology. Methods: Circulating large extracellular vesicle (LEV) abundance and morphology were characterized by complementary single-vesicle nano-flow cytometry and super-resolution microscopy. Proteomic profiling further delineated LEV molecular cargoes and associated biological pathways between patients with BAV and TAV. Results: We demonstrate that patients with BAVs exhibited fundamentally altered circulating LEV profiles compared to TAVs. Super-resolution imaging revealed BAV-specific organization of platelet- and leukocyte-associated adhesion molecules into discrete EV membrane microdomains. Proteomic profiling identified distinct LEV cargoes between BAV and TAV, including a BAV-specific, previously unrecognized neutrophil-associated signature enriched for proteins involved in neutrophil degranulation and innate immunity. Consistent with this phenotype, BAV displayed alterations in platelet- and neutrophil-associated LEV populations, suggesting enhanced (thrombo-)inflammatory activity. Lastly, distinct associations between LEV populations and clinical parameters in BAV and TAV suggest that LEV profiles reflect morphology-specific aspects of disease severity. Conclusions: Comprehensive single-vesicle analysis and bulk proteomic profiling identified a distinct circulating LEV signature in BAV-associated CAVD, characterized by endothelial activation and reciprocal platelet-neutrophil interactions. These findings reveal previously unrecognized differences in circulating LEVs between BAV and TAV and highlight their potential as biomarkers of valve morphology-specific pathophysiology.

molecular biology↗

bioRxiv2026

Platelet-endothelial crosstalk drives distinct endothelial dysfunction in bicuspid aortic valve disease

Background: Bicuspid aortic valves (BAV) predispose individuals to premature development of aortic stenosis (AS). The abnormal hemodynamic environment of BAV affects both platelets and valvular endothelial cells (VECs), but whether platelet-derived signals contribute to valve morphology-specific endothelial dysfunction remains unknown. Methods: Platelets and VECs were obtained from patients with BAVs or tricuspid aortic valves (TAVs) undergoing valve replacement for AS. Platelets were activated to generate platelet releasate (PR). PR composition and its effects on VECs were investigated using complementary molecular, multi-omic, functional, and computational approaches. Results: BAV and TAV patients exhibited markedly distinct PR profiles, which translated into differential endothelial responses. Strikingly, BAV-derived PR elicited a substantially more pronounced endothelial dysfunction phenotype, characterized by widespread molecular reprogramming and functional alterations. Integrated multi-omics uncovered mitochondrial dysfunction as a central feature of BAV PR-induced endothelial injury, accompanied by activation of pathways spanning endothelial remodeling, migration, and immune-cell recruitment. These molecular signatures translated into mitochondrial depolarization, altered mitochondrial dynamics, enhanced VEC migration, and increased neutrophil adhesion and chemotaxis. Finally, computational ligand-receptor and ligand-target analyses identified candidate signaling axes linking platelet-derived mediators to endothelial reprogramming, highlighting potential therapeutic targets. Conclusions: We provide the first direct evidence that platelet activation contributes to AS initiation through the induction of endothelial dysfunction and that these effects are amplified in BAV. These findings identify platelet-VEC crosstalk as a previously unrecognized mechanism linking abnormal valve hemodynamics to disease onset. Targeting platelet-derived mediators may represent a novel therapeutic strategy for AS, specifically in BAV.

molecular biology↗

bioRxiv2025

Nanoparticle-enabled plasma proteomics of a mouse atherosclerosis model

BackgroundDyslipidemia, marked by elevated LDL-cholesterol (LDL-C), is a major risk factor for coronary heart disease. Mouse experimental models, such as Ldlr-/- mice that develop atherosclerosis and metabolic disorders when fed a high-fat diet (HFD), are indispensable for studying disease mechanisms and identifying potential biomarkers. ObjectivesWe aimed to profile the plasma proteins in experimental murine atherosclerosis with the primary goal of detecting low-abundant proteins. MethodsLdlr-/- mice were fed a chow diet or HFD for 3 (n = 27 per group) or 6 months (n = 12 per group). Plasma samples were processed using nanoparticle technology (Proteograph(R) XT Assay; Seer, Inc), and peptides were analyzed using the Orbitrap Astral (Thermo Fisher Scientific) in data-independent acquisition mode. For tissue proteomics, ten aortas were pooled for n = 4 pools per time point and diet, and n = 6 livers per time point and diet. Peptides were analyzed on the Orbitrap Exploris 480 in data-dependent mode. Proteomes were queried against the Tabula Muris mouse single-cell, STRING, and Gene Ontology databases, and queried against a genome-wide association list of 419 risk loci for coronary artery disease. ResultsWe sequenced 5,080 plasma proteins, surpassing previous reports by 10-fold. The prototypical apolipoproteins and complement factors were the most abundant proteins, whereas proteins associated with cytokine/chemokine signaling represented the previously uncharted mouse plasma proteome. We divided the proteome into quartiles (Q1-Q4) to monitor sweeping changes over time. Proteins with a sustained enrichment in HFD (n = 705) were indicative of liver cell subtypes (Tabula Muris). Whereas proteins that moved up from the lower quartiles - Q2 (n = 228), Q3 (115) and Q4 (63) - associated with leukocyte, fibroblasts, and endothelial cell markers, indicating that signatures of inflammation and endothelial activation increase with disease progression. Notably, 86 and 146 proteins were increased at 3 and 6 months, including MMP-12 and COL6A3. Classical apolipoproteins exhibited heterogeneous responses - SAA3 and APOC2 increased, while APOA1, APOE, and LCAT decreased with high-fat feeding, suggesting impaired high-density lipoprotein (HDL) functionality. Proteins shared between plasma and aorta were enriched for extracellular matrix components, while those overlapping with liver reflected metabolic processes. Finally, 120 coronary artery disease (CAD)-associated proteins from human GWAS were detected in Ldlr-/- plasma, of which 4, including lipoprotein lipase, exhibited an increase in abundance with HFD. ConclusionsNanoparticle-dependent proteome enrichment coupled to mass spectrometry may allow to identify novel plasma biomarkers in Ldlr-/- mice and facilitate monitoring of candidate proteins associated with human disease mechanisms in preclinical interventional studies, thereby opening new avenues for understanding disease pathology and uncovering novel molecular contributors.

pathology↗

bioRxiv2023

Single-cell T cell receptor sequencing of paired tissue and blood samples reveals clonal expansion of CD8+ effector T cells in patients with calcific aortic valve disease

Calcific aortic valve disease (CAVD) is a complex cardiovascular pathology, culminating in aortic stenosis, heart failure and premature mortality, with no comprehensive treatment strategy, except valve replacement. While T cells have been identified within the valve, their contribution to pathogenesis remains unclear. To elucidate the heterogenous phenotype of the immune populations present within patients with CAVD, deep phenotypic screens of paired valve and peripheral blood cells were conducted via flow cytometry (n=20) and immunohistochemistry (n=10). Following identification of a significant population of memory T cells; specifically, CD8+ T cells within the valve, single cell RNA sequencing and paired single T cell receptor sequencing was conducted on a further 4 patients on CD45+ CD3+, CD4+ or CD8+ T cells. Through unsupervised clustering, 7 T cell populations were identified within the blood and 10 identified within the valve. Tissue resident memory (TRM) T cells were detected for the first time within the valve, exhibiting a highly cytotoxic, activated, and terminally differentiated phenotype. This pan-pro-inflammatory signal was differentially identified in T cells originating from the valve, and not observed in the blood, indicative of an adaptive, local not-systemic inflammatory signature in CAVD patients. T cell receptor analysis identified hyperexpanded clones within the CD8+ T cell central memory (TCM) population, with TRM cells comprising the majority of large and medium clonal expansion within the entire T cell population. Clonal interaction network analysis demonstrated the greatest proportion of clones originating from CD8+ T cell effector memory (TEM) and CD4+ naive / TCM populations and ending in the CD8+ TRM and CD8+ TCM clusters, suggesting a clonal expansion and predicted trajectory of T cells towards a tissue resident, cytotoxic environment within the valve. CDR3 epitope predictive analysis identified 7 potential epitope targets, of which GALNT4 and CR1L have previously been implicated in a cardiovascular context as mediators of inflammation. Taken together, the data identified T cell sub-populations within the context of CAVD and further predicted possible epitopes responsible for the clonal expansion of the valvular T cells, which may be important for propagating inflammation in CAVD.

immunology↗