Endothelial cytoskeletal elements are critical for flow-mediated dilation in human coronary arterioles
Mitochondrial H2O2 contributes to flow-mediated dilation (FMD) in human coronary arterioles (HCA). We examined the hypothesis that the endothelial cytoskeleton plays a critical role in transducing endothelial wall shear stress into a stimulus for releasing mitochondrial ROS. Phallacidin together with ?-, ?-tubulin antibodies and Mito-Tracker Red showed the proximity of F-actin, microtubules and mitochondria in endothelial cells. Cytochalasin D (CytoD) and nocodazole (Noc) disrupted endothelial F-actin and microtubules in HCA, respectively, concurrent with a reduction in the generation of cytosolic O2 ? and H2O2 (hydroethidine and dichlorodihydrofluorescein fluorescence) and mitochondrial superoxide (mitoSox) during flow (control: 3.51.6, Cyto D: 0.510.2, Noc: 0.810.6). FMD, but not the dilation to bradykinin or papaverine, was reduced by Cyto D (2610% vs. 563%) or Noc (2611% vs. 587%). These results suggest that cytoskeletal elements are a critical component of the signaling mechanism linking endothelial shear stress and mitochondrial release of ROS in the human coronary microcirculation.
cytoskeleton shear stress coronary microcirculation oxidative stress