cGMP-dependent protein kinase contributes to hydrogen sulfide-stimulated vasorelaxation

PLoS One. 2012;7(12):e53319. doi: 10.1371/journal.pone.0053319. Epub 2012 Dec 28.

Abstract

A growing body of evidence suggests that hydrogen sulfide (H₂S) is a signaling molecule in mammalian cells. In the cardiovascular system, H₂S enhances vasodilation and angiogenesis. H₂S-induced vasodilation is hypothesized to occur through ATP-sensitive potassium channels (K(ATP)); however, we recently demonstrated that it also increases cGMP levels in tissues. Herein, we studied the involvement of cGMP-dependent protein kinase-I in H₂S-induced vasorelaxation. The effect of H₂S on vessel tone was studied in phenylephrine-contracted aortic rings with or without endothelium. cGMP levels were determined in cultured cells or isolated vessel by enzyme immunoassay. Pretreatment of aortic rings with sildenafil attenuated NaHS-induced relaxation, confirming previous findings that H₂S is a phosphodiesterase inhibitor. In addition, vascular tissue levels of cGMP in cystathionine gamma lyase knockouts were lower than those in wild-type control mice. Treatment of aortic rings with NaHS, a fast releasing H₂S donor, enhanced phosphorylation of vasodilator-stimulated phosphoprotein in a time-dependent manner, suggesting that cGMP-dependent protein kinase (PKG) is activated after exposure to H₂S. Incubation of aortic rings with a PKG-I inhibitor (DT-2) attenuated NaHS-stimulated relaxation. Interestingly, vasodilatory responses to a slowly releasing H₂S donor (GYY 4137) were unaffected by DT-2, suggesting that this donor dilates mouse aorta through PKG-independent pathways. Dilatory responses to NaHS and L-cysteine (a substrate for H₂S production) were reduced in vessels of PKG-I knockout mice (PKG-I⁻/⁻). Moreover, glibenclamide inhibited NaHS-induced vasorelaxation in vessels from wild-type animals, but not PKG-I⁻/⁻, suggesting that there is a cross-talk between K(ATP) and PKG. Our results confirm the role of cGMP in the vascular responses to NaHS and demonstrate that genetic deletion of PKG-I attenuates NaHS and L-cysteine-stimulated vasodilation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aorta / drug effects
  • Aorta / physiology
  • Cells, Cultured
  • Cyclic GMP-Dependent Protein Kinases / antagonists & inhibitors
  • Cyclic GMP-Dependent Protein Kinases / genetics
  • Cyclic GMP-Dependent Protein Kinases / metabolism
  • Cyclic GMP-Dependent Protein Kinases / physiology*
  • Cyclic Nucleotide Phosphodiesterases, Type 5 / metabolism
  • Cyclic Nucleotide Phosphodiesterases, Type 5 / physiology
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiology
  • Female
  • Hydrogen Sulfide / pharmacology*
  • Male
  • Mice
  • Mice, Knockout
  • Phosphodiesterase 5 Inhibitors / pharmacology
  • Rats
  • Rats, Wistar
  • Vasodilation / drug effects*
  • Vasodilation / genetics

Substances

  • Phosphodiesterase 5 Inhibitors
  • Cyclic GMP-Dependent Protein Kinases
  • Cyclic Nucleotide Phosphodiesterases, Type 5
  • Hydrogen Sulfide

Grant support

This work has been funded by Fondazione per la Ricerca Scientifica Termale FoRST (Rome, Italy (to GC) and co-financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: Thalis; Investing in knowledge society through the European Social Fund and Aristeia 2011 (1436) to AP, by EU FP7 REGPOT CT-2011-285950 – “SEE-DRUG” and by the COST Action BM1005 (ENOG: European network on gasotransmitters). This work has also been partially supported by a Discovery grant from the Natural Sciences and Engineering Research Council of Canada and the Heart and Stroke Foundation Canada. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.