The role of dynamic mechanical environments in vesicle trafficking

Extracellular vesicles (EVs) mediate interactions between cells and with the extracellular matrix. The aim of this study is to elucidate how vesicle trafficking is affected by changes in the mechanical environment of the cell. Caveolin-1 (cav-1), a structural protein located in caveolae invaginations of the cell membrane, is required for the formation of a specific subset of EVs that participate in pathological remodeling in coronary artery disease. Caveolae are known to participate in mechanotransduction, and given that vascular smooth muscle cells (SMCs) reside within dynamic vascular tissues, studies into the mechanical-dependent regulation of cav-1 positive EV formation could provide new insight into the role of mechanics in arterial remodeling. We inhibited known mechanotransductive proteins to assess changes in the formation and release of cav-1 positive EVs from SMCs exposed to cyclic stretch or no stretch for 72 hours. The greatest amount of cav-1 internalization and cav-1 positive EV release occurred under the cyclic stretch condition when compared to the no stretch condition. We then treated SMCs with ROCK inhibitor (ROCKi) or Src inhibitor (Srci) and evaluated cytoskeletal rearrangement and cav-1 levels after 72 hours. SMCs treated with ROCKi showed increased cav-1 positive EV release under both cyclic stretch and no stretch conditions. On the other hand, Srci treatment caused the SMCs to exhibit decreased levels of cav-1 positive EV release when compared to ROCK inhibition and control