Abstract
Carotid atherosclerosis (CAS) is a major contributor to ischemic stroke, with vascular calcification driving disease progression. However, the molecular mechanisms driving vascular calcification in CAS remain unelucidated. Previous studies have confirmed that bone morphogenetic proteins (BMPs) play essential roles in calcification; however, the regulatory mechanisms of BMP6 signaling in vascular calcification remain unclear. This study aims to investigate the role of BMP6 in vascular calcification in CAS and the underlying mechanisms. A subset of endothelial cells (ECs) with high BMP6 expression, which interacted with specific vascular smooth muscle cells (VSMCs) via the BMP signaling pathway, is identified using single-cell RNA sequencing of human CAS plaques. In vitro experiments demonstrate BMP6-induced osteogenic differentiation of VSMCs. Moreover, BMP6 activates the small mother against decapentaplegic (SMAD) signaling pathway by binding to the BMP6 receptor complex. Experimental results from endothelium-specific BMP6 knockout (BMP6(ECKO)ApoE(-/-)) and overexpression mice confirm that BMP6 exacerbates vascular calcification, whereas its knockdown reduces calcific lesions. Additionally, disturbed flow conditions upregulate BMP6 expression by suppressing Krüppel-like factor 4 and linking hemodynamic forces to BMP6-mediated calcification. These findings suggest that BMP6 is a key regulator of vascular calcification in CAS, driven by EC-VSMC interactions and hemodynamic stress.