Biology subjects

Jensen, L. F.

Publications and source records attributed to Jensen, L. F..

3 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

MyD88-dependent signaling promotes smooth muscle cell phenotypic modulation and fibrous cap formation in murine atherosclerosis

Background and aimsRecruitment of fibrous cap smooth muscle cells (SMCs) is critical for stabilizing atherosclerotic plaques and preventing rupture. This study investigated the SMC-specific role of the myeloid differentiation primary response protein 88 (Myd88) gene, encoding an adaptor protein essential for signaling downstream of several cytokine and pattern-recognition receptors, in this process. MethodsThe effects of MyD88 knockdown were assessed in cultured rat aortic SMCs. SMC-specific knockout of Myd88 was induced in mice using the Cre/lox method, followed by induction of atherosclerosis by proprotein convertase subtilisin/kexin type 9 gene transfer and a high-fat diet for 12 or 20 weeks. Effects on plaque and fibrous cap formation were studied by immunofluorescence and in situ hybridization. ResultsMyd88 knockdown reduced proliferation and migration of cultured SMCs and preserved contractile gene expression under inflammatory stimulation. SMC-specific Myd88 deficiency in hyperlipidemic mice did not significantly alter plaque size in the aortic root but reduced the number of cap SMCs in advanced lesions at 20 weeks and in the most atherosclerosis-susceptible aortic sinus at 12 weeks. Other plaque features, including macrophages, necrotic core size, and collagen content, were not significantly affected. Notably, MyD88 deficiency preserved the contractile phenotype of medial SMCs beneath plaques, suggesting that impaired phenotypic modulation contributed to reduced cap SMC recruitment. ConclusionsMyD88-dependent signaling promotes medial SMC phenotypic modulation and the recruitment of fibrous cap SMCs during atherogenesis. These findings highlight MyD88 as a mediator linking inflammatory signaling to protective fibrous cap formation. HighlightsO_LIKnockdown of MyD88 preserves the contractile phenotype of cultured smooth muscle cells subjected to inflammatory cytokines. C_LIO_LITargeting MyD88 in murine atherosclerosis inhibits fibrous cap formation. C_LIO_LITargeting MyD88 in murine atherosclerosis preserves the contractile phenotype of medial smooth muscle cells beneath the plaque. C_LI

pathology↗

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↗