The interplay of membrane cholesterol and substrate on vascular smooth muscle biomechanics.pdf

Cholesterol is implicated not only in the formation of foam cells within atherosclerotic plaques but also in regulating cell migration during atherogenesis. As atherosclerosis progresses, arterial walls stiffen, impacting the microenvironment of vascular smooth muscle cells (VSMCs). The study aims to investigate how membrane cholesterol and substrate stiffness coordinate to regulate VSMC biomechanics, potentially influencing VSMC migration and atherosclerotic plaque development. Using methyl-β-cyclodextrin, researchers manipulated membrane cholesterol levels in VSMCs cultured on collagen-coated polyacrylamide gels with varying stiffness. Atomic force microscopy (AFM) assessed VSMC stiffness and integrin-fibronectin (FN) adhesion, while confocal microscopy visualized actin filament alignment. The contractile force of rat aortas was measured ex vivo using a multi-wire myograph system. Results showed that cholesterol depletion and substrate softening decreased VSMC stiffness, FN adhesion, and induced cytoskeletal disorganization. Conversely, cholesterol enrichment increased stiffness, FN adhesion, and cytoskeletal organization compared to depleted cells, enhancing aortic contractile force. Membrane cholesterol and substrate stiffness synergistically affected VSMC elastic modulus by regulating actin cytoskeleton organization. Overall, cholesterol and substrate stiffness play crucial roles in VSMC biomechanics, influencing cell adhesion, cytoskeletal organization, and contractile function, which are relevant factors in atherosclerotic plaque formation and vascular disease progression.