Biology subjects

Markov, A.

Publications and source records attributed to Markov, A..

4 recordsLinked to original sources

bioRxiv2025

Mechanical stretch regulates inflammatory signaling in human smooth muscle cells

Background and aimsVascular smooth muscle cells (SMCs) cultured under standard static conditions adopt a modulated phenotype that resembles the SMC states found in atherosclerotic plaques, but the mechanical determinants of this drift are not well defined. We investigated how mechanical loading shapes SMC phenotype and inflammatory signaling. MethodsHuman aortic SMCs were maintained under static conditions, physiological cyclic stretch (10% elongation), or pathological stretch (15% elongation) and analyzed by bulk and single-cell RNA sequencing. Mechanistic experiments included siRNA-mediated knockdown of IKBKB, p65 immunofluorescence, and regulon inference from single-cell transcriptomes. ResultsStretch regulated cell cycle, contractile, and inflammatory gene programs in an intensity-dependent manner: 10% stretch suppressed basal and TNF-induced inflammatory gene expression, whereas 15% stretch did not. The anti-inflammatory effect of physiological stretch required IKBKB, yet the proportion of cells with nuclear p65 was unchanged, indicating that stretch constrains NF-{kappa}B output downstream of p65 nuclear entry rather than by blocking translocation. Single-cell RNA sequencing resolved nine states for SMCs in culture whose transcriptomes overlapped substantially with the modulated mesenchymal populations of human coronary and carotid plaques, and physiological stretch attenuated pro-inflammatory gene expression across the major clusters. Regulatory network analysis identified inflammatory transcription factors (RELB, CEBPB/D, IRF1/2, STAT2) as less active under physiological stretch, whereas mechano-lineage regulators (MEF2C, TEAD1, SMAD6) were selectively induced, providing candidate mediators of the effect. ConclusionsStatic culture represents a disease-like SMC baseline that physiological stretch attenuates, in part by constraining NF-{kappa}B transcriptional output at a step downstream of p65 nuclear entry. Graphical abstractPhysiological stretch (10%) maintains a low-inflammatory, healthy-like state in human aortic smooth muscle cells, whereas its absence (static culture) or excess (15% stretch) favors an inflammatory, plaque-like state. NF-{kappa}B-p65 enters the nucleus under all conditions; physiological stretch constrains its inflammatory output downstream of nuclear entry. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/685276v2_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@bbcf58org.highwire.dtl.DTLVardef@29ba95org.highwire.dtl.DTLVardef@1989aa4org.highwire.dtl.DTLVardef@1d0c253_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2025

Mouse, pig, and human atherosclerotic lesions have common and distinct mesenchymal cell populations

The proliferation and phenotypic modulation of smooth muscle cells (SMCs) to alternative mesenchymal states is a key process by which atherosclerotic lesions grow. The underlying mechanisms can be studied in mouse and pig atherosclerosis, but it remains unclear to what extent the mesenchymal plaque cell types in these species recapitulate human disease. Here, we integrate published and new single-cell RNA sequencing data of plaque mesenchymal cells from human carotid and coronary arteries, pig aorta and coronary arteries, and mouse brachiocephalic arteries. By applying consensus across multiple integration and gene homology-matching strategies, we identify a conserved core continuum of mesenchymal plaque cells, ranging from SMCs to extracellular matrix-producing fibroblast-like cells, which is stable across species and vascular beds. Notably, several other populations differed between human and experimental lesions. Subpopulations of SMCs marked by DLX5 and RERGL expression were specific to human carotid and coronary plaques, respectively. Mesenchymal cell states with strong pro-angiogenic and inflammation-associated gene signatures were identified in pig, but not human, coronary plaque datasets, with the pro-angiogenic phenotype associated with early stages of necrotic core development. Pericytes were solely present in pig and human plaques, while chondrocyte-like cells were unique to mouse lesions. The presented interspecies maps of mesenchymal cell diversity, and their markers may inform translational research into the role of SMCs and their derived progeny in atherosclerosis.

systems biology↗

bioRxiv2024

Mapping atherogenesis mechanisms in smooth muscle cells by targeting genes linked to coronary artery disease

Recent genome-wide association studies (GWAS) have identified multiple vascular cell-expressed genes linked to coronary artery disease (CAD), suggesting that smooth muscle cells (SMCs) and SMC-derived metaplastic cells are promising targets for novel antiatherosclerosis therapies. However, the disease-promoting pathways of most GWAS-identified genes are unknown, hindering their translation into therapeutic targets. This study integrated public GWAS data for CAD and single-cell RNA sequencing (scRNA-seq) analyses of human atherosclerotic plaques to identify 20 GWAS risk genes with a putative mechanism of action in SMCs or SMC-derived cells. Gene perturbation experiments in SMCs coaxed to plaque-relevant phenotypes revealed that the selected risk genes, despite encoding very different types of proteins, regulated shared sets of genes associated with contractile functions, cell cycle pathways, NF{kappa}B, and type I interferon signaling. By integrating information about GWAS gene effect direction and a deep analysis of cholesterol- and stretch-induced gene modules in SMCs, we find evidence that cholesterol-induced signaling is a pro-atherogenic disease mechanism in SMCs that is upregulated by detrimental and downregulated by protective GWAS genes. Overall, our study identifies a set of candidate disease mechanisms in SMCs that are regulated by multiple GWAS genes across several SMC assays. Furthermore, it provides proof-of-concept for using GWAS gene effect directionality to predict the pathogenic effect of candidate disease mechanisms that can be extended to other GWAS genes and cell types in the future.

cell biology↗

bioRxiv2020

Structural variability, expression profile and pharmacogenetics properties of TMPRSS2 gene as a potential target for COVID-19 therapy

The human serine protease TMPRSS2 gene is involved in the priming of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins being one of the possible targets for COVID-19 therapy. TMPRSS2 gene is possibly co-expressed with SARS-CoV-2 cell receptor genes ACE2 and BSG, but only TMPRSS2 demonstrates tissue-specific expression in alveolar cells according to single cell RNA sequencing data. Our analysis of the structural variability of the TMPRSS2 gene based on genome-wide data of 76 human populations demonstrates that functionally significant missense mutation in exon 6/7 in TMPRSS2 gene, was found in many human populations in relatively high frequency, featuring region-specific distribution patterns. The frequency of the missense mutation encoded by the rs12329760, which previously was found to be associated with prostate cancer, is ranged between 10% and 63% being significantly higher in populations of Asian origin compared to European populations. In addition to SNPs, two copy numbers variants (CNV) were detected in the TMPRSS2 gene. Number of microRNAs have been predicted to regulate TMPRSS2 and BSG expression levels, but none of them is enriched in lung or respiratory tract cells. Several well studied drugs can downregulate the expression of TMPRSS2 in human cells, including Acetaminophen (Paracetamol) and Curcumin. Thus TMPRSS2 interaction with the SARS-CoV-2, its structural variability, gene-gene interactions, and expression regulation profiles, and pharmacogenomics properties characterize this gene as a potential target for COVID-19 therapy.

genomics↗