TY - JOUR T1 - Hydrogen sulfide preserves eNOS function by inhibiting PYK2: implications for cardiomyocyte survival and cardioprotection JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.117.109645 SP - mol.117.109645 AU - Sofia-Iris Bibli AU - Csaba Szabo AU - Athanasia Chatzianastasiou AU - Bert Luck AU - Sven Zukunft AU - Ingrid Fleming AU - Andreas Papapetropoulos Y1 - 2017/01/01 UR - http://molpharm.aspetjournals.org/content/early/2017/10/13/mol.117.109645.abstract N2 - Hydrogen sulfide (H2S) exhibits beneficial effects in the cardiovascular system, many of which depend on nitric oxide (NO). Proline-rich tyrosine kinase 2 (PYK2), a redox-sensitive tyrosine kinase, directly phosphorylates and inhibits eNOS. Herein, we investigated the ability of H2S to relieve PYK2-mediated eNOS inhibition and evaluated the importance of the H2S/PYK2/eNOS axis on cardiomyocyte injury in vitro and in vivo. Exposure of H9c2 cardiomyocytes to H2O2 or pharmacological inhibition of H2S production increased PYK2 (Y402) and eNOS (Y656) phosphorylation. These effects were blocked by treatment with Na2S or by overexpression of cystathionine γ-lyase (CSE). In addition, PYK2 overexpression reduced eNOS activity in a H2S-reversible manner. The viability of cardiomyocytes exposed to H2O2 was reduced and declined further following inhibition of H2S production. PYK2 downregulation, L-cysteine supplementation or CSE overexpression alleviated the effects of H2O2 on H9c2 survival. Moreover, H2S promoted PYK2 sulfhydration and inhibited its activity. In vivo, H2S administration reduced reactive oxygen species levels, as well as PYK2 (Y402) and eNOS (Y656) phosphorylation. Pharmacological blockade of PYK2 or inhibition of PYK2 activation by Na2S reduced myocardial infarct size in mice. Co-administration of a PYK2 inhibitor and Na2S did not result in additive effects on infarct size. We conclude that H2S relieves the inhibitory effect of PYK2 on eNOS, allowing the latter to produce greater amounts of NO affording cardioprotection. Our results unravel the existence of a novel H2S-NO interaction and identify PYK2 as a crucial target for the protective effects of H2S under conditions of oxidative stress. ER -