Phosphorylation of TRPC6 Channels at Thr69 Is Required for Anti-hypertrophic Effects of Phosphodiesterase 5 Inhibition*
| Autor: | Ryuji Inoue, Naoyuki Kitajima, Michio Nakaya, Kenta Watanabe, Tomomi Ide, Yoji Sato, Hitoshi Kurose, Motohiro Nishida |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Male
medicine.medical_specialty Phosphodiesterase Inhibitors Mutation Missense Cardiomegaly Biology Biochemistry Piperazines Sildenafil Citrate TRPC6 Cell Line Potassium Chloride Diglycerides Mice Regulator of G protein signaling Internal medicine medicine Cyclic GMP-Dependent Protein Kinases TRPC6 Cation Channel Animals Humans Myocytes Cardiac Calcium Signaling Sulfones Molecular Biology Protein kinase C RGS2 Protein Kinase C Calcium signaling Diacylglycerol kinase TRPC Cation Channels Cyclic Nucleotide Phosphodiesterases Type 5 Cell Biology Phosphodiesterase 5 Inhibitors Cell biology Rats Enzyme Activation Endocrinology Amino Acid Substitution Purines Gene Knockdown Techniques GTP-Binding Protein alpha Subunits Gq-G11 Calcium Signal transduction cGMP-dependent protein kinase Signal Transduction |
| Popis: | Activation of Ca(2+) signaling induced by receptor stimulation and mechanical stress plays a critical role in the development of cardiac hypertrophy. A canonical transient receptor potential protein subfamily member, TRPC6, which is activated by diacylglycerol and mechanical stretch, works as an upstream regulator of the Ca(2+) signaling pathway. Although activation of protein kinase G (PKG) inhibits TRPC6 channel activity and cardiac hypertrophy, respectively, it is unclear whether PKG suppresses cardiac hypertrophy through inhibition of TRPC6. Here, we show that inhibition of cGMP-selective PDE5 (phosphodiesterase 5) suppresses endothelin-1-, diacylglycerol analog-, and mechanical stretch-induced hypertrophy through inhibition of Ca(2+) influx in rat neonatal cardiomyocytes. Inhibition of PDE5 suppressed the increase in frequency of Ca(2+) spikes induced by agonists or mechanical stretch. However, PDE5 inhibition did not suppress the hypertrophic responses induced by high KCl or the activation of protein kinase C, suggesting that PDE5 inhibition suppresses Ca(2+) influx itself or molecule(s) upstream of Ca(2+) influx. PKG activated by PDE5 inhibition phosphorylated TRPC6 proteins at Thr(69) and prevented TRPC6-mediated Ca(2+) influx. Substitution of Ala for Thr(69) in TRPC6 abolished the anti-hypertrophic effects of PDE5 inhibition. In addition, chronic PDE5 inhibition by oral sildenafil treatment actually induced TRPC6 phosphorylation in mouse hearts. Knockdown of RGS2 (regulator of G protein signaling 2) and RGS4, both of which are activated by PKG to reduce G alpha(q)-mediated signaling, did not affect the suppression of receptor-activated Ca(2+) influx by PDE5 inhibition. These results suggest that phosphorylation and functional suppression of TRPC6 underlie prevention of pathological hypertrophy by PDE5 inhibition. |
| Databáze: | OpenAIRE |
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