Hydrogen Sulfide Preserves Endothelial Nitric Oxide Synthase Function by Inhibiting Proline-Rich Kinase 2: Implications for Cardiomyocyte Survival and Cardioprotection

Abstract

Hydrogen sulfide (HS) 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 endothelial NO synthase (eNOS). We investigated the ability of HS to relieve PYK2-mediated eNOS inhibition and evaluated the importance of the HS/PYK2/eNOS axis on cardiomyocyte injury in vitro and in vivo. Exposure of H9c2 cardiomyocytes to HO or pharmacologic inhibition of HS production increased PYK2 (Y402) and eNOS (Y656) phosphorylation. These effects were blocked by treatment with NaS or by overexpression of cystathionine -lyase (CSE). In addition, PYK2 overexpression reduced eNOS activity in a HS-reversible manner. The viability of cardiomyocytes exposed to ΗΟ was reduced and declined further after the inhibition of HS production. PYK2 downregulation, l-cysteine supplementation, or CSE overexpression alleviated the effects of HO on H9c2 cardiomyocyte survival. Moreover, HS promoted PYK2 sulfhydration and inhibited its activity. In vivo, HS administration reduced reactive oxygen species levels, as well as PYK2 (Y402) and eNOS (Y656) phosphorylation. Pharmacologic blockade of PYK2 or inhibition of PYK2 activation by NaS reduced myocardial infarct size in mice. Coadministration of a PYK2 inhibitor and NaS did not result in additive effects on infarct size. We conclude that HS relieves the inhibitory effect of PYK2 on eNOS, allowing the latter to produce greater amounts of NO, thereby affording cardioprotection. Our results unravel the existence of a novel HS-NO interaction and identify PYK2 as a crucial target for the protective effects of HS under conditions of oxidative stress.

Hydrogen Sulfide Attenuates Renin Angiotensin and Aldosterone Pathological Signaling to Preserve Kidney Function and Improve Exercise Tolerance in Heart Failure

“…Multiple studies have previously reported that H 2 S augments the bioavailability and signaling of NO 18, 31, 32, 33. The current study found that JK-1 treatment initiated at 3 or 10 weeks post TAC resulted in significantly elevated levels of nitrite in circulation, heart, and kidney (Figures 7D to 7F).…”

“…Endothelial dysfunction results in the inactivation of endothelial NOS (eNOS) and attenuated NO bioavailability, over-produced inflammatory cytokines, and increased oxidative stress, which further exacerbate the progression of HF 6, 48, 49. Multiple studies have reported that H 2 S augments endothelial function via reducing oxidative stress, promoting eNOS activity, and other mechanisms 16, 33, 50, 51; However, there is a lack of information regarding the endothelium-protective actions of H 2 S in the setting of HF. In the current study, we observed that the aortic rings of isolated from HF + Control mice exhibited diminished response to acetylcholine, verifying that TAC- induced HF indeed caused severe endothelium dysfunction.…”

Nitroglycerine limits infarct size through S-nitrosation of cyclophilin D: a novel mechanism for an old drug

“…24 Re-activation 24 or preservation of eNOS function 25 during the early reperfusion period serves as a promising therapeutic cardioprotective strategy. 26 Endogenously generated and exogenously applied • NO exerts its beneficial effects either through cGMP/PKG-dependent pathways or by directly targeting the mitochondria. 27,28 The former pathways have been shown to involve, among others, K ATP channels, the sodium-proton exchanger and protein kinase Ce leading to inhibition of mPTP opening, 3,29 while the latter relies on S-nitrosation of complex I to reduce ROS production.…”

An Update on Hydrogen Sulfide and Nitric Oxide Interactions in the Cardiovascular System

“…A novel H 2 S donor, SG-1002, prevented the transition from compensated to decompensated heart failure in part via upregulation of eNOS and increased nitric oxide bioavailability [ 67 ]. Bibli et al reported that H 2 S preserved eNOS activity via inhibiting proline-rich tyrosine kinase 2 (PYK2) in H9c2 cells under oxidative stress [ 162 ]. Sodium nitrite (NaNO 2 ) significantly improves LV function in ischemia-induced chronic heart failure via increasing H 2 S bioavailability, Nrf2 activation, and antioxidant defenses [ 163 ].…”

“… The interactions between H2S and NO in cardioprotection. [ 161 ]: Wu et al; [ 162 ]: Bibli et al; [ 163 ]: Donnarumma et al; [ 164 ]: Karwi et al …”