Title :
Caveola ATP synthase mediates ATP release in vascular endothelial cells exposed to shear stress
Author :
Yamamoto, Kimiko ; Obi, Syotaro ; Shimizu, Nobutaka ; Kumagaya, Shinichiro ; Ando, Joji
Author_Institution :
Univ. of Tokyo, Tokyo
Abstract :
Endothelial cells (ECs) release ATP in response to shear stress, a mechanical force generated by blood flow, and the ATP released modulates EC functions through activation of purinoceptors. The molecular mechanism of the shear-stress-induced ATP release, however, has not been fully understood. In this study, we have demonstrated that cell-surface ATP synthase is involved in shear stress-induced ATP release. Immunofluorescence staining of human pulmonary artery ECs (HPAECs) showed that cell-surface ATP synthase is distributed in lipid rafts and co-localized with caveolin-1. When exposed to shear stress, HPAECs released ATP in a dose-dependent manner, and the ATP release was markedly suppressed by a membrane-impermeable ATP synthase inhibitor, angiostatin, and by an anti-ATP synthase antibody. Depletion of plasma membrane cholesterol with methyl-beta cyclo-dextrin (MbetaCD) disrupted lipid rafts and abolished co-localization of ATP synthase with caveolin-1, which resulted in a marked reduction in shear-stress-induced ATP release. Down-regulation of caveolin-1 expression by transfection of caveolin-1 siRNA also markedly suppressed ATP-releasing responses to shear stress. These results suggest that the localization and targeting of ATP synthase to caveolae/lipid rafts, is critical for shear stress-induced ATP release by HPAECs.
Keywords :
biomembrane transport; enzymes; fluorescence; haemodynamics; lipid bilayers; molecular biophysics; ATP release; angiostatin; anti-ATP synthase antibody; blood flow; caveola ATP synthase; caveolin-1; human pulmonary artery endothelial cells; immunofluorescence staining; lipid rafts; membrane-impermeable ATP synthase inhibitor; methyl-beta cyclodextrin; plasma membrane cholesterol; purinoceptors; shear stress; vascular endothelial cells; Arteries; Biomembranes; Blood flow; Cells (biology); Humans; Immune system; Inhibitors; Lipidomics; Plasmas; Stress;
Conference_Titel :
Micro-NanoMechatronics and Human Science, 2007. MHS '07. International Symposium on
Conference_Location :
Nagoya
Print_ISBN :
978-1-4244-1858-9
Electronic_ISBN :
978-1-4244-1858-9
DOI :
10.1109/MHS.2007.4420887