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: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 various cell phenotypes in response to pathologic stimuli1-3. In atherosclerosis, these phenotypically modulated SMCs regulate plaque composition and influence the risk of major adverse cardiovascular events4,5. We found that PRDM16, a transcription factor that is genetically associated with cardiovascular disease, is highly expressed in arterial SMCs and downregulated during SMC fate switching in human and mouse atherosclerosis. Loss of Prdm16 in SMCs of mice activates a synthetic modulation program under homeostatic conditions. Single cell analyses show that loss of Prdm16 drives a synthetic program in all SMC populations. Upon exposure to atherogenic stimuli, SMC-selective Prdm16 deficient mice develop SMC-rich, fibroproliferative plaques that contain few foam cells. Acute loss of Prdm16 results in the formation of collagen-rich lesions with thick fibrous caps. Reciprocally, increasing PRDM16 expression in SMCs blocks synthetic processes, including migration, proliferation, and fibrosis. Mechanistically, PRDM16 binds to chromatin and decreases activating histone marks at synthetic genes. Altogether, these results define PRDM16 as a critical determinant of SMC identity and atherosclerotic lesion composition.
Project description:Abdominal aortic aneurysm (AAA) is usually asymptomatic until life-threatening complications occur, predominantly involving aortic rupture. Currently, no drug-based treatments are available, primarily due to limited understanding of AAA pathogenesis. The transcriptional regulator PR domain–containing protein 16 (PRDM16) is highly expressed in the aorta, but its functions in the aorta are largely unknown. By RNA-seq analysis, we found that vascular smooth muscle cell–specific (VSMC-specific) Prdm16-knockout (Prdm16SMKO) mice already showed extensive changes in the expression of genes associated with extracellular matrix (ECM) remodeling and inflammation in the abdominal aorta under normal housing conditions without any pathological stimuli. Human AAA lesions displayed lower PRDM16 expression. Periadventitial elastase application to the suprarenal region of the abdominal aorta aggravated AAA formation in Prdm16SMKO mice. During AAA development, VSMCs undergo apoptosis because of both intrinsic and environmental changes, including inflammation and ECM remodeling. Prdm16 deficiency promoted inflammation and apoptosis in VSMCs. A disintegrin and metalloproteinase 12 (ADAM12) is a gelatinase that can degrade various ECMs. We found that ADAM12 is a target of transcriptional repression by PRDM16. Adam12 knockdown reversed VSMC apoptosis induced by Prdm16 deficiency. Our study demonstrated that PRDM16 deficiency in VSMCs promoted ADAM12 expression and aggravates AAA formation, which may provide potential targets for AAA treatment.
Project description:This SuperSeries is composed of the following subset Series:; GSE13835: Smooth muscle cells in atherosclerosis-prone and resistant regions of the aorta of C57Bl/6 mice at age of 4 months; GSE13836: Smooth muscle cells in atherosclerosis-prone and resistant regions of the aorta of apoE-/- mice at age of 4 months Experiment Overall Design: Refer to individual Series
Project description:Human genetic studies have repeatedly associated ADAMTS7 with atherosclerotic cardiovascular disease. Subsequent investigations in mice demonstrated that ADAMTS7 is proatherogenic and induced in response to vascular injury and that the proatherogenicity of ADAMTS7, a secreted protein, is due to its catalytic activity. However, the cell-specific mechanisms governing ADAMTS7 proatherogenicity remain unclear. To determine which vascular cell types express ADAMTS7, we interrogated single-cell RNA sequencing of human carotid atherosclerosis and found ADAMTS7 expression in smooth muscle cells (SMCs), endothelial cells (ECs), and fibroblasts. We subsequently created SMC- and EC-specific Adamts7 conditional knockout and transgenic mice. Conditional knockout of Adamts7 in either cell type is insufficient to reduce atherosclerosis, whereas transgenic induction in either cell type increases atherosclerosis. In SMC transgenic mice, this increase coincides with an expansion of lipid-laden SMC foam cells and decreased fibrous cap formation. RNA-sequencing in SMCs revealed an upregulation of lipid uptake genes typically assigned to macrophages. Subsequent experiments demonstrated that ADAMTS7 increases SMC oxLDL uptake through increased CD36 levels. Furthermore, Cd36 expression is increased due to increased levels of PU.1, a transcription factor typically associated with myeloid fate determination. In summary, Adamts7 expression in either SMCs or ECs promotes SMC foam cell formation and atherosclerosis. In SMCs, ADAMTS7 promotes oxLDL uptake via increased PU.1 and Cd36 expression, thereby increasing SMC foam cell formation and atherosclerosis.
Project description:Smooth muscle cells (SMC) play significant roles in atherosclerosis via phenotypic switching, a pathological process in which SMC transdifferentiation into macrophage-like SMCs. Furthermore, during transdifferentiation, the SMCs' expression of PADI4 upregulating and SMC generated extracellular trap, a web-like structure, which plays key role in the development of atherosclerosis plaque. To reveal the function of SMC's generating ETs during atherosclerosis and to identify molecular targets for disease therapy, we combined SMC fate mapping and single-cell RNA sequencing of mouse atherosclerotic plaques.