Role of caveolin in hemodynamic force-mediated endothelial changes

Background. Caveolin has been shown to play an important role in signal transduction and nitric oxide synthase production. The purpose of this study was to investigate whether caveolin was tyrosine phosphorylated or activated by shear stress or cyclic strain in bovine aortic endothelial cells (BAECs). Matherials and methods. BAECs were subjected to an average of 10% strain at a rate of 60 cycles/min or a laminar shear stress of 10 dyn/cm(2) for up to 4 h. Immunoblotting with anticaveolin antibody was performed to assess activation of caveolin, Coimmunoprecipitation of anticaveolin antibody with anti-tyrosine phosphorylation antibody was performed to detect the tyrosine phosphorylation of caveolin. Results. Neither cyclic strain nor shear stress at physiologic levels altered the level of caveolin protein. Tyrosine phosphorylation of caveolin could not be observed at any time under either cyclic strain or shear stress condition. Conclusion. Although hemodynamic forces alter nitric oxide synthase production and activate signal transduction, caveolin levels or activity is not altered in endothelial cells exposed to shear stress or cyclic strain, (C) 2000 Academic Press.