Abstract Arterial stiffening is influenced by the organization of focal adhesions in vascular smooth muscle cells (VSMCs). We investigated the contribution of α v integrins to both arterial wall stiffness (Young’s modulus measured by echography) and VSMC stiffness (assessed by atomic force microscopy). Mice with VSMC-specific deletion of α v integrins (α v SMKO ) were compared with controls at baseline and following angiotensin II infusion. Unstimulated cultured α v -deficient (α v -KD) VSMCs exhibited higher stiffness than controls, with a further increase after angiotensin II. To interpret AFM measurements performed at shallow indentation depths, we developed a computational model of VSMC nanoindentation. Simulations showed that higher apparent Young’s moduli at shallow indentation fall within the experimental range of α v -KD cells. These cells also displayed enhanced actin polymerization, further amplified by angiotensin II through the formation of cortical F-actin. In vivo, arterial pressure and wall elastic modulus were similar between α v SMKO and control mice at baseline and after angiotensin II, despite α v SMKO mice exhibiting lower elastin and higher collagen content under angiotensin II. Together, these findings indicate that the comparable increase in arterial stiffness observed in α v SMKO mice under angiotensin II is driven primarily by elevated VSMC stiffness resulting from cortical actin redistribution, which outweighs extracellular matrix changes.
Bascetin et al. (Sat,) studied this question.