[Regulation of cardiovascular functions by the phosphorylation of TRPC channels].
Calcium ions (Ca²(+)) play an essential role in homeostasis and the activity of cardiovascular cells. Ca²(+) influx across the plasma membrane induced by neurohumoral factors or mechanical stress elicits physiologically relevant timing and spatial patterns of Ca²(+) signaling, which leads to the activation of various cardiovascular functions, such as muscle contraction, gene expression, and hypertrophic growth of myocytes. A canonical transient receptor potential protein subfamily member, TRPC6, which is activated by diacylglycerol and mechanical stretch, works as an upstream regulator of the Ca²(+) signaling pathway required for pathological hypertrophy. We have recently found that the inhibition of cGMP-selective phosphodiesterase 5 (PDE5) suppresses agonist- and mechanical stretch-induced hypertrophy through inhibition of Ca²(+) influx in rat cardiomyocytes. The inhibition of PDE5 suppressed the increase in frequency of Ca²(+) spikes induced by receptor stimulation or mechanical stretch. Activation of protein kinase G by PDE5 inhibition phosphorylated TRPC6 proteins at Thr⁶⁹ and prevented TRPC6-mediated Ca²(+) influx. Substitution of Ala for Thr⁶⁹ in TRPC6 abolished the antihypertrophic effects of PDE5 inhibition. These results suggest that phosphorylation and functional suppression of TRPC6 underlies the prevention of cardiac hypertrophy by PDE5 inhibition. As TRPC6 proteins are also expressed in vascular smooth muscle cells and reportedly participate in vascular remodeling, TRPC6 blockade may be an effective therapeutic strategy for preventing pathologic cardiovascular remodeling.
Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. nishida@phar.kyushi-u.ac.jp
Motohiro
M
Nishida
Shota
S
Saiki
Naoyuki
N
Kitajima
Michio
M
Nakaya
Yoji
Y
Sato
Hitoshi
H
Kurose
D019943:Amino Acid Substitution; D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D006332:Cardiomegaly / Q000209:etiology / Q000517:prevention & control; D002320:Cardiovascular Physiological Phenomena; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000502:physiology; D015195:Drug Design; D051379:Mice; D009131:Muscle, Smooth, Vascular; D058986:Phosphodiesterase 5 Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D051381:Rats; D013314:Stress, Mechanical; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*; D000074287:TRPC6 Cation Channel
D058986:Phosphodiesterase 5 Inhibitors; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C492146:Trpc6 protein, mouse; D017869:Cyclic GMP-Dependent Protein Kinases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5