Activation of endothelial TRPV4 channels mediates flow-induced dilation in human coronary arterioles: role of Ca2+ entry and mitochondrial ROS signaling

作者：Aaron H. Bubolz, Suelhem A. Mendoza, Xiaodong Zheng, Natalya S. Zinkevich, Rongshan Li, David D. Gutterman, David X. Zhang · 发表于：American Journal of Physiology-Heart and Circulatory Physiology · 年份：2011 · DOI：10.1152/ajpheart.00717.2011 · 被引用次数：144 · 研究领域：Ion Channels and Receptors、Cardiovascular, Neuropeptides, and Oxidative Stress Research、Nitric Oxide and Endothelin Effects

In human coronary arterioles (HCAs) from patients with coronary artery disease, flow-induced dilation is mediated by a unique mechanism involving the release of H(2)O(2) from the mitochondria of endothelial cells (ECs). How flow activates ECs to elicit the mitochondrial release of H(2)O(2) remains unclear. Here, we examined the role of the transient receptor potential vanilloid type 4 (TRPV4) channel, a mechanosensitive Ca(2+)-permeable cation channel, in mediating ROS formation and flow-induced dilation in HCAs. Using RT-PCR, Western blot analysis, and immunohistochemical analysis, we detected the mRNA and protein expression of TRPV4 channels in ECs of HCAs and cultured human coronary artery ECs (HCAECs). In HCAECs, 4α-phorbol-12,13-didecanoate (4α-PDD), a selective TRPV4 agonist, markedly increased (via Ca(2+) influx) intracellular Ca(2+) concentration. In isolated HCAs, activation of TRPV4 channels by 4α-PDD resulted in a potent concentration-dependent dilation, and the dilation was inhibited by removal of the endothelium and by catalase, a H(2)O(2)-metabolizing enzyme. Fluorescence ROS assays showed that 4α-PDD increased the production of mitochondrial superoxide in HCAECs. 4α-PDD also enhanced the production of H(2)O(2) and superoxide in HCAs. Finally, we found that flow-induced dilation of HCAs was markedly inhibited by different TRPV4 antagonists and TRPV4-specific small interfering RNA. In conclusion, the endothelial TRPV4 channel is critically involved in flow-mediat...