Single-cell genomics reveals a novel cell state during smooth muscle cell phenotypic switching and potential therapeutic targets for atherosclerosis in mouse and human [human]
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ABSTRACT: Single-cell genomics reveals a novel cell state during smooth muscle cell phenotypic switching and potential therapeutic targets for atherosclerosis in mouse and human [human]
Project description:Smooth muscle cells (SMC) play significant roles in atherosclerosis via phenotypic switching, a pathological process in which SMC dedifferentiation, migration and transdifferentiation into other cell types. Yet, how SMC contribute to pathophysiology of atherosclerosis remains elusive. To reveal the trajectories of SMC transdifferentiation during atherosclerosis and to identify molecular targets for disease therapy, we combined SMC fate mapping and single-cell RNA sequencing of both mouse and human atherosclerotic plaques.
Project description:Smooth muscle cells (SMC) play significant roles in atherosclerosis via phenotypic switching, a pathological process in which SMC dedifferentiation, migration and transdifferentiation into other cell types. Yet, how SMC contribute to pathophysiology of atherosclerosis remains elusive. To reveal the trajectories of SMC transdifferentiation during atherosclerosis and to identify molecular targets for disease therapy, we combined SMC fate mapping and single-cell RNA sequencing of both mouse and human atherosclerotic plaques.
Project description:Objective: Hematopoietic ChemR23 deficiency was shown to reduce atherosclerotic lesions by increasing M2 macrophages, but conflicting results in systemically deficient mice suggest a cell-specific function of ChemR23. Therefore, we aimed to study the role of ChemR23 particularly on vascular smooth muscle cells (VSMCs) in atherosclerosis. Methods and Results: Mice with a non-hematopoietic cell ChemR23 deficiency due to bone marrow transplantation of Apolipoprotein E deficient bone marrow into irradiated ChemR23e/e Apoe-/- double deficient recipient mice (Apoe-/- ►ChemR23e/e Apoe-/-) were fed a Western Diet for 6- or 12-weeks. Subsequent analysis revealed an increased lesion size and enhanced VSMC proliferation and VSMC foam cells in Apoe-/- ►ChemR23e/e Apoe-/- mice. Bulk RNA sequencing of adventitia-stripped aortas of Apoe-/- ►ChemR23e/e Apoe-/- mice exposed an increase in gene expression of synthetic VSMC markers such as Lgals3 and Cd68, while contractile genes were downregulated. Likewise, single-cell transcriptome data from advanced human atherosclerotic plaques uncovered the highest ChemR23 expression in contractile VSMCs while its expression in synthetic VSMCs was markedly reduced. In vitro, treatment of human aortic smooth muscle cells (HASMCs) with α-NETA, a small molecule inhibitor of ChemR23, increased synthetic gene expression but downregulated expression of TGFB, ABCA1, ABCG1 and SRB1. Further, α-NETA-treated HASMCs downregulated TGFB secretion, increased cholesterol uptake but decreased cholesterol efflux, and showed enhanced cell proliferation. Agonizing ChemR23 with its bona fide ligand chemerin 9 (C9) had no effect on synthetic gene expression but mitigated the effects of α-NETA on gene expression, cholesterol uptake, efflux, and cell proliferation. In vivo, both α-NETA and C9 treatment of Apoe-/- mice over 4 weeks WD revealed therapeutic potential. C9 reduced general inflammatory burden while α-NETA promoted an atheroprotective M2 macrophage phenotype. Conclusions: These findings reveal a critical role of ChemR23 in regulating VSMC phenotype switching thereby affecting atherosclerosis and suggest ChemR23 as a therapeutic target to either modulate inflammation (C9) or macrophage polarization (α-NETA) in atherosclerotic disease.
Project description:Single-cell genomics reveals a novel cell state during smooth muscle cell phenotypic switching and potential therapeutic targets for atherosclerosis in mouse and human
Project description:Single-cell genomics reveals a novel cell state during smooth muscle cell phenotypic switching and potential therapeutic targets for atherosclerosis in mouse and human [mouse]
Project description:Vascular smooth muscle cells (VSMCs) within atherosclerotic lesions undergo a phenotypic switching in a KLF4-dependent manner. Glycolysis plays important roles in transdifferentiation of somatic cells, however, it is unclear whether and how KLF4 mediates the link between glycolytic switch and VSMCs phenotypic transitions. Here, we show that KLF4 upregulation accompanies VSMCs phenotypic switching in atherosclerotic lesions. KLF4 enhances the metabolic switch to glycolysis through increasing PFKFB3 expression. Inhibiting glycolysis suppresses KLF4-induced VSMCs phenotypic switching, demonstrating that glycolytic shift is required for VSMCs phenotypic switching. Mechanistically, KLF4 upregulates expression of circCTDP1 and eEF1A2, both of which cooperatively promote PFKFB3 expression. TMAO induces glycolytic shift and VSMCs phenotypic switching by upregulating KLF4. Our study indicates that KLF4 mediates the link between glycolytic switch and VSMCs phenotypic transitions, suggesting that a previously unrecognized KLF4-eEF1A2/circCTDP1-PFKFB3 axis plays crucial roles in VSMCs phenotypic switching.
Project description:Vascular smooth muscle cells (SMCs) normally exist in a contractile state but can undergo fate switching to produce a variety of cell phenotypes in response to pathologic stimuli. In atherosclerosis, these phenotypically modulated SMCs play a critical role in determining plaque composition and the risk of major adverse cardiovascular events. We found that PRDM16, a transcription factor that has been genetically implicated in cardiovascular disease, is highly expressed in arterial SMCs, and downregulated during SMC fate switching in human and mouse atherosclerosis. Deletion of Prdm16 in SMCs of mice activates the synthetic modulation program in arteries under homeostatic conditions. Upon exposure to atherogenic conditions, these mice form strikingly dense, SMC-rich, fibroproliferative plaques that contain few foam cells. Acute deletion of Prdm16 in SMCs triggers a similar fibrotic response, resulting in the formation of collagen-rich lesions with thick fibrous caps – a hallmark of enhanced lesion stability. Reciprocally, ectopic expression of PRDM16 in cultured cells is sufficient to block SMC synthetic processes, including migration, proliferation, and fibrosis. Mechanistically, PRDM16 binds to chromatin and decreases activating histone marks at synthetic genes. Altogether, our results define PRDM16 as a specific gatekeeper of the synthetic SMC switch and reveal that PRDM16 levels in SMCs predetermine atherogenic lesion composition.
Project description:Vascular smooth muscle cells (SMCs) normally exist in a contractile state but can undergo fate switching to produce a variety of cell phenotypes in response to pathologic stimuli. In atherosclerosis, these phenotypically modulated SMCs play a critical role in determining plaque composition and the risk of major adverse cardiovascular events. We found that PRDM16, a transcription factor that has been genetically implicated in cardiovascular disease, is highly expressed in arterial SMCs, and downregulated during SMC fate switching in human and mouse atherosclerosis. Deletion of Prdm16 in SMCs of mice activates the synthetic modulation program in arteries under homeostatic conditions. Upon exposure to atherogenic conditions, these mice form strikingly dense, SMC-rich, fibroproliferative plaques that contain few foam cells. Acute deletion of Prdm16 in SMCs triggers a similar fibrotic response, resulting in the formation of collagen-rich lesions with thick fibrous caps – a hallmark of enhanced lesion stability. Reciprocally, ectopic expression of PRDM16 in cultured cells is sufficient to block SMC synthetic processes, including migration, proliferation, and fibrosis. Mechanistically, PRDM16 binds to chromatin and decreases activating histone marks at synthetic genes. Altogether, our results define PRDM16 as a specific gatekeeper of the synthetic SMC switch and reveal that PRDM16 levels in SMCs predetermine atherogenic lesion composition.
Project description:To evaluate the roles of glutaminase 1 (GLS1) in vascular smooth muscle cells (VSMCs) phenotypic switching and aortic dissection (AD). Integrative transcriptomic analyses were performed to identify the candidate genes involved in VSMC phenotypic switching in AD. The expression of GLS1 in VSMCs was assessed by qRT-PCR, Western blot and immunofluorescence. RNA-sequencing analysis was performed to recapitulate possible changes in the transcriptome profile of GLS1 in VSMCs. We identified GLS1 as a potential regulator in AD. GLS1 expression was significantly downregulated in VSMCs from both human AD aortic tissues and mouse models. Mechanistically, down-regulation of GLS1 impaired glutamate metabolism, leading to reduced levels of glutathione and α-ketoglutarate, thereby promoting mitochondrial dysfunction and accumulation of reactive oxygen species, which activated the PI3K/AKT pathway and ultimately triggered VSMC phenotypic switching. These findings revealed a critical role of GLS1-mediated glutamate metabolism in VSMC phenotypic switching and suggest a promising therapeutic target for AD.