Shear Stress Protects against Endothelial Regulation of Vascular Smooth Muscle Cell Migration in a Coculture System

Abstract

Vascular endothelial cells (ECs) are constantly exposed to blood flow-induced shear stress; these forces strongly influence the behaviors of neighboring vascular smooth muscle cells (VSMCs). VSMC migration is a key event in vascular wall remodeling. In this study, the authors assessed the difference between VSMC migration in VSMC/EC coculture under static and shear stress conditions. Utilizing a parallel-plate coculture flow chamber system and Transwell migration assays, they demonstrated that human ECs cocultured with VSMCs under static conditions induced VSMC migration, whereas laminar shear stress (1.5 Pa, 15 dynes/cm2) applied to the EC side for 12 h significantly inhibited this process. The changes in VSMC migration is mainly dependent on the close interactions between ECs and VSMCs. Western blotting showed that there was a consistent correlation between the level of Akt phosphorylation and the efficacy of shear stress-mediated EC regulation of VSMC migration. Wortmannin and Akti significantly inhibited the EC-induced effect on VSMC Akt phosphorylation and migration. These results indicate that shear stress protects against endothelial regulation of VSMC migration, which may be an atheroprotective function on the vessel wall.

PDGF-BB and TGF-β1 on cross-talk between endothelial and smooth muscle cells in vascular remodeling induced by low shear stress

“…After 8 h for attachment, the membrane was placed with the EC side down in the six-well plate, and VSMCs were seeded on the inside of the membrane at a density of 2 × 10 5 cells per cup. NSS and LowSS were subjected to ECs in the flow chamber system (20)(21)(22).…”

“…There are 1.6 million pores/cm 2 on the membrane, and each pore is 0.4 μm in diameter. The porous structure permitted the interaction between ECs and VSMCs and allowed the respective analysis on these two kinds of cells (20)(21)(22).…”

“…PDGF-BB, and TGF-β in cocultured VSMCs (17) and that shear stress modulates VSMC migration, apoptosis, proliferation, and gene expressions in an EC-dependent manner (1,20,21). Shear stress acting on ECs changes the phenotype of the cocultured VSMCs, with the subsequent alterations in the EC release of proinflammatory cytokines, as well as proliferation, apoptosis, and gene expression that induce atherogenesis (22,23).…”

Biomechanical regulation of vascular smooth muscle cell functions: from in vitro to in vivo understanding

“…Under static conditions, ECs induce VSMC migration in a co-culture system, but shear stress inhibits VSMC migration through regulation of ECs at 15 dyn cm 22 [115]. The mechanism involved is that low shear stress increases endothelial PDGF expression [116][117][118] and the upregulated expression of PDGF-DD in ECs mediates VSMC phenotypic modulation [119,120].…”

Live cell imaging of mechanotransduction

“…These mechanical forces can be perceived by cells and thus cause different physiological consequences, including deformation and regulation of cellular polarization (Katsumi et al 2004;Ingber 2006), migration (Wang et al 2006;Hsu et al 2007) and differentiation (Datta et al 2006;Obi et al 2009;Pek et al 2010). It remains unclear, however, how cells perceive the mechanical stimuli and transmit them into cellular biochemical signals.…”