Referenced in: none

Automatically associated channels: TRP , TRPC , TRPC3 , TRPC6 , TRPC7

Title: Cilostazol suppresses angiotensin II-induced vasoconstriction via protein kinase A-mediated phosphorylation of the transient receptor potential canonical 6 channel.

Authors: Kinue Nishioka, Motohiro Nishida, Marina Ariyoshi, Zhong Jian, Shota Saiki, Mayumi Hirano, Michio Nakaya, Yoji Sato, Satomi Kita, Takahiro Iwamoto, Katsuya Hirano, Ryuji Inoue, Hitoshi Kurose

Journal, date & volume: Arterioscler. Thromb. Vasc. Biol., 2011 Oct , 31, 2278-86

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/21799177

Abstract
The goal of this study was to determine whether inhibition of transient receptor potential canonical (TRPC) channels underlies attenuation of angiotensin II (Ang II)-induced vasoconstriction by phosphodiesterase (PDE) 3 inhibition.Pretreatment of rat thoracic aorta with cilostazol, a selective PDE3 inhibitor, suppressed vasoconstriction induced by Ang II but not that induced by KCl. The Ang II-induced contraction was largely dependent on Ca(2+) influx via receptor-operated cation channels. Cilostazol specifically suppressed diacylglycerol-activated TRPC channels (TRPC3/TRPC6/TRPC7) through protein kinase A (PKA)-dependent phosphorylation of TRPC channels in HEK293 cells. In contrast, we found that phosphorylation of TRPC6 at Thr69 was essential for the suppression of Ang II-induced Ca(2+) influx by PDE3 inhibition in rat aortic smooth muscle cells (RAoSMCs). Cilostazol specifically induced phosphorylation of endogenous TRPC6 at Thr69. The endogenous TRPC6, but not TRPC3, formed a ternary complex with PDE3 and PKA in RAoSMCs, suggesting the specificity of TRPC6 phosphorylation by PDE3 inhibition. Furthermore, inhibition of PDE3 suppressed the Ang II-induced contraction of reconstituted ring with RAoSMCs, which were abolished by the expression of a phosphorylation-deficient mutant of TRPC6.PKA-mediated phosphorylation of TRPC6 at Thr69 is essential for the vasorelaxant effects of PDE3 inhibition against the vasoconstrictive actions of Ang II.