Trpm2 enhances physiological bioenergetics and protects against pathological oxidative cardiac injury: Role of Pyk2 phosphorylation

Barbara A. Miller, Ju Fang Wang, Jianliang Song, Xue Qian Zhang, Iwona Hirschler-Laszkiewicz, Santhanam Shanmughapriya, Dhanendra Tomar, Sudasan Rajan, Arthur M. Feldman, Muniswamy Madesh, Shey Shing Sheu, Joseph Y. Cheung

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The mechanisms by which Trpm2 channels enhance mitochondrial bioenergetics and protect against oxidative stress-induced cardiac injury remain unclear. Here, the role of proline-rich tyrosine kinase 2 (Pyk2) in Trpm2 signaling is explored. Activation of Trpm2 in adult myocytes with H2O2 resulted in 10- to 21-fold increases in Pyk2 phosphorylation in wild-type (WT) myocytes which was significantly lower (~40%) in Trpm2 knockout (KO) myocytes. Pyk2 phosphorylation was inhibited (~54%) by the Trpm2 blocker clotrimazole. Buffering Trpm2-mediated Ca2+ increase with 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) resulted in significantly reduced pPyk2 in WT but not in KO myocytes, indicating Ca2+ influx through activated Trpm2 channels phosphorylated Pyk2. Part of phosphorylated Pyk2 translocated from cytosol to mitochondria which has been previously shown to augment mitochondrial Ca2+ uptake and enhance adenosine triphosphate generation. Although Trpm2-mediated Ca2+ influx phosphorylated Ca2+-calmodulin kinase II (CaMKII), the CaMKII inhibitor KN93 did not significantly affect Pyk2 phosphorylation in H2O2-treated WT myocytes. After ischemia/reperfusion (I/R), Pyk2 phosphorylation and its downstream prosurvival signaling molecules (pERK1/2 and pAkt) were significantly lower in KO-I/R when compared with WT-I/R hearts. After hypoxia/reoxygenation, mitochondrial membrane potential was lower and superoxide level was higher in KO myocytes, and were restored to WT values by the mitochondria-targeted superoxide scavenger MitoTempo. Our results suggested that Ca2+ influx via tonically activated Trpm2 phosphorylated Pyk2, part of which translocated to mitochondria, resulting in better mitochondrial bioenergetics to maintain cardiac health. After I/R, Pyk2 activated prosurvival signaling molecules and prevented excessive increases in reactive oxygen species, thereby affording protection from I/R injury.

Original languageEnglish (US)
Pages (from-to)15048-15060
Number of pages13
JournalJournal of Cellular Physiology
Volume234
Issue number9
DOIs
StatePublished - Sep 2019

All Science Journal Classification (ASJC) codes

  • Physiology
  • Clinical Biochemistry
  • Cell Biology

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