title: cGMP-dependent protein kinase contributes to hydrogen sulfide-stimulated vasorelaxation.
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.
authors.affiliation: Department of Experimental Pharmacology, Faculty of Pharmacy, University of Naples-Federico II, Naples, Italy.
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: Bucci
authors.forename: Andreas
authors.initials: A
authors.lastname: Papapetropoulos
authors.forename: Valentina
authors.initials: V
authors.lastname: Vellecco
authors.forename: Zongmin
authors.initials: Z
authors.lastname: Zhou
authors.forename: Altaany
authors.initials: A
authors.lastname: Zaid
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Giannogonas
authors.forename: Anna
authors.initials: A
authors.lastname: Cantalupo
authors.forename: Sandeep
authors.initials: S
authors.lastname: Dhayade
authors.forename: Katia P
authors.initials: KP
authors.lastname: Karalis
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Robert
authors.initials: R
authors.lastname: Feil
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cirino
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000378:metabolism / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005260:Female; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D058986:Phosphodiesterase 5 Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects* / Q000235:genetics
chemical_list: D058986:Phosphodiesterase 5 Inhibitors; D017869:Cyclic GMP-Dependent Protein Kinases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D006862:Hydrogen Sulfide