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

Arterioscler Thromb Vasc Biol. 2011 Oct;31(10):2278-86. doi: 10.1161/ATVBAHA.110.221010. Epub 2011 Jul 28.


Objective: 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.

Methods and results: 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.

Conclusions: PKA-mediated phosphorylation of TRPC6 at Thr69 is essential for the vasorelaxant effects of PDE3 inhibition against the vasoconstrictive actions of Ang II.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / metabolism*
  • Animals
  • Aorta, Thoracic / drug effects
  • Aorta, Thoracic / enzymology
  • Calcium Signaling / drug effects
  • Cilostazol
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Diglycerides / metabolism
  • Dose-Response Relationship, Drug
  • HEK293 Cells
  • Humans
  • Male
  • Mice
  • Muscle, Smooth, Vascular / drug effects*
  • Muscle, Smooth, Vascular / enzymology
  • Mutation
  • Myocytes, Smooth Muscle / drug effects*
  • Myocytes, Smooth Muscle / enzymology
  • Phosphodiesterase 3 Inhibitors / pharmacology*
  • Phosphorylation
  • Protein Processing, Post-Translational
  • Rats
  • Rats, Sprague-Dawley
  • TRPC Cation Channels / drug effects*
  • TRPC Cation Channels / genetics
  • TRPC Cation Channels / metabolism
  • TRPC6 Cation Channel
  • Tetrazoles / pharmacology*
  • Transfection
  • Vasoconstriction / drug effects*
  • Vasoconstrictor Agents / pharmacology
  • Vasodilator Agents / pharmacology*
  • rho GTP-Binding Proteins / metabolism


  • Diglycerides
  • Phosphodiesterase 3 Inhibitors
  • TRPC Cation Channels
  • TRPC6 Cation Channel
  • TRPC6 protein, human
  • Tetrazoles
  • Trpc6 protein, mouse
  • Trpc6 protein, rat
  • Vasoconstrictor Agents
  • Vasodilator Agents
  • Angiotensin II
  • Cyclic AMP-Dependent Protein Kinases
  • rho GTP-Binding Proteins
  • Cilostazol