Quantitative Analysis of Contractile Ability of Vascular Smooth Muscle Cells Using a Micropillar Substrate and a Laser Nanoscissor System

Abstract

Vascular cell senescence and vascular aging are known to be associated with serious vascular diseases, such as arteriosclerosis and aneurysm generation. However, it is unclear how cellular dedifferentiation and senescence affects cellular contractile force which is especially important for vascular smooth muscle cells. Here we investigated the changes in the cellular contractile ability during repeatedly passage-cultivation that promotes cell dedifferentiation and senescence. Porcine aortic vascular smooth muscle cells exposed to several passage-cultivation were seeded on the polydimethylsiloxane-based elastic micropillar array substrates, and their whole cell contractile forces were preciously estimated by the deflection of the pillars. Furthermore, we dissected intracellular actin stress fibers in living cells by laser irradiation to release their pretension, observed the dynamic behavior of the dissected stress fibers, and estimated the internal tension of individual stress fibers. We found that the both of the whole cell contractile forces and the internal tension of individual stress fibers were significantly decreased in cell dedifferentiation and senescence induced by repeatedly passage-cultivation, and the decrease was more sensitive in the individual stress fibers than in the whole cell. These results indicate that cellular contractile forces are deeply involved in cellular dedifferentiation and senescence.