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Activation of endothelial TRPV4 channels mediates flow-induced dilation in human coronary arterioles: role of Ca2+ entry and mitochondrial ROS signaling. Am J Physiol Heart Circ Physiol 2012 Feb 01;302(3):H634-42

Date

12/06/2011

Pubmed ID

22140047

Pubmed Central ID

PMC3353785

DOI

10.1152/ajpheart.00717.2011

Scopus ID

2-s2.0-84863016934   77 Citations

Abstract

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-mediated dilation of HCAs. TRPV4-mediated Ca(2+) entry may be an important signaling event leading to the flow-induced release of mitochondrial ROS in HCAs. Elucidation of this novel TRPV4-ROS pathway may improve our understanding of the pathogenesis of coronary artery disease and/or other cardiovascular disorders.

Author List

Bubolz AH, Mendoza SA, Zheng X, Zinkevich NS, Li R, Gutterman DD, Zhang DX

Authors

David D. Gutterman MD Sr Associate Director, Professor in the Medicine department at Medical College of Wisconsin
David X. Zhang MD, PhD Associate Professor in the Medicine department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Aged
Arterioles
Atrial Appendage
Calcium
Calcium Signaling
Cells, Cultured
Coronary Circulation
Endothelial Cells
Female
Humans
Male
Middle Aged
Mitochondria
Oxidative Stress
Phenanthridines
RNA, Small Interfering
Reactive Oxygen Species
TRPV Cation Channels
Vasodilation
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a