Smad3 regulates smooth muscle cell fate and mediates adverse remodeling and calcification of the atherosclerotic plaque

Abstract

Atherosclerotic plaques consist mostly of smooth muscle cells (SMC), and genes that in uence SMC biology can modulate coronary artery disease (CAD) risk. Allelic variation at 15q22.33 has been identi ed by genome-wide association studies to modify the risk of CAD, and is associated with expression of SMAD3 in SMC, but the mechanism by which this gene modi es CAD risk remains poorly understood. SMC-speci c deletion of Smad3 in a murine atherosclerosis model resulted in greater plaque burden, more positive remodeling, and increased vascular calci cation. Single-cell transcriptomic analyses revealed that loss of Smad3 altered SMC transition cell state toward two fates: a novel SMC phenotype that governs both vascular remodeling and recruitment of in ammatory cells, as well as a chondromyocyte fate. The remodeling population was marked by uniquely high Mmp3 and Cxcl12 expression, and its appearance correlated with higher risk plaque features such as increased positive remodeling and macrophage content. Further, investigation of transcriptional mechanisms by which Smad3 alters SMC cell fate revealed novel roles for Hox and Sox transcription factors whose direct interaction with Smad3 regulate an extensive transcriptional program balancing remodeling and vascular extracellular matrix with signi cant implications for atherosclerotic and Mendelian aortic aneurysmal diseases. Together, these data suggest that Smad3 expression in SMC inhibits the emergence of speci c SMC phenotypic transition cells that mediate adverse plaque features, including positive remodeling, monocyte recruitment, and vascular calci cation.

Integrative single-cell meta-analysis reveals disease-relevant vascular cell states and markers in human atherosclerosis

“…3, Supplementary Table 6 ), which we termed “foam-like” SMCs. These cells also expressed ECM-remodeling genes such as TIMP1 and pro-inflammatory genes CCL19, CCL2, IGFBP3 , consistent with a potential role in leukocyte recruitment 71 .…”

“…Previous studies suggest that SMAD3 antagonizes atheroprotective TCF21 modulation activity, constraining SMCs from migrating to the lesion and fibrous cap 98 . Moreover, recent SMC-specific Smad3 KO mice resulted in increased proportions of FCs at the expense of fibromyocytes 71 . Interestingly we observed increased SMAD3 motif accessibility in ECM-rich SMCs (fibromyocytes and FCs) compared to contractile SMCs using our combined human scRNA-seq based regulons and snATAC data.…”

“…Though it has been shown that both fibromyocytes and FCs originate from SMCs [18][19][20]97 , these two ECM-rich phenotypes are postulated to play opposing roles in plaque stability 9 and their exact lineage relationship is not well understood. Murine studies have previously suggested fibromyocytes are progenitors of FCs 71 . Using pseudotime analysis we revealed a branchpoint where transitional SMCs could adopt either fibromyocyte or FC fates.…”

Vascular smooth muscle cells in intimal hyperplasia, an update

“…The SMAD protein family, particularly nuclear factors Smad2 and Smad3, mediate canonical TGF-β signaling. Interestingly, the canonical TGFβ signaling via the suppressor of mothers against decapentaplegic (SMAD) transcription factors SMAD2 and SMAD3 promotes the expression of differentiation marker SM22α, SMMHC and ACTA2, via enhanced binding of SRF to CArG elements within the promoters of these genes ( Low et al, 2019 ; Cheng et al, 2022 ). TGFβ also stimulates the RhoA/ROCK signaling pathway and MRTFs release ( O'Connor et al, 2016 ).…”

Targeting the Crosstalk of Immune Response and Vascular Smooth Muscle Cells Phenotype Switch for Arteriovenous Fistula Maturation

“…VSMCs play a critical role in these events and a switch in VSMC phenotype may affect these molecular processes to either enhance the favorable mechanism or impede the process [ 8 , 11 , 16 , 17 ]. There are reports in the literature on the role of VSMCs plasticity and phenotype switch in regulating plaque progression, atherosclerosis progression, vessel wall inflammation, adverse remodeling, and arterial calcification and targeting VSMCs plasticity and phenotype switch [ 16 , 19 , 29 , 30 , 31 , 32 ]. However, the role of VSMCs in vascular remodeling in AVF maturation has not been reported.…”