Preservation of nitric oxide-induced relaxation of porcine coronary artery: roles of the dimers of soluble guanylyl cyclase, phosphodiesterase type 5, and cGMP-dependent protein kinase

Abstract

Soluble guanylyl cyclase (sGC), phosphodiesterase type 5 (PDE5), and guanosine 3',5'-cyclic monophosphate (cGMP)-dependent protein kinase (PKG) are all dimeric. The present study was to determine the role of their dimeric status in nitric oxide-induced vasodilatation. In isolated porcine coronary arteries, after 20 h incubation with serum-free medium, serum-containing medium, or phosphate-buffered saline solution, the protein levels of the dimers of sGC, PDE5, and PKG were diminished while the monomer levels remained unchanged, associated with reduced cGMP elevation in response to DETA NONOate and decreased PDE5 activity; the activity of PKG was not significantly altered. DETA NONOate caused a greater relaxation in arteries incubated for 20 vs. 2 h. The relaxant response was largely abolished by 1H-[1, 2, 4]oxadiazolo[4,3-a]quinoxalin-1-one, an sGC inhibitor. Zaprinast, a PDE5 inhibitor, had no effect on relaxation caused by DETA NONOate of arteries incubated for 20 h but augmented the response incubated for 2 h. A greater relaxation to 8-bromo-guanosine 3'5'-cyclic monophosphate occurred in arteries incubated for 20 than for 2 h. The protein level of the dimers but not monomers of PDE5 was reduced by dithiothreitol and unaffected by hydrogen peroxide, accompanied with decreased PDE5 activity and reduced response to DETA NONOate. These results demonstrate that the dimeric but not monomeric status of sGC and PDE5 of coronary arteries are closely related to their activities. The preserved vasodilator response after 20 h incubation may result in part from a synchronous reduction of the dimer levels of sGC and PDE5 as well as an augmented response to cGMP.

Sulfhydration-associated phosphodiesterase 5A dimerization mediates vasorelaxant effect of hydrogen sulfide

“…Recently, Gao, et al found an interesting mechanism for the regulation of sGC and PDE 5A activity, namely sulfhydryl-dependent dimerization formation. Heterodimers are formed by disulfide bonds of sGC protein α and β subunits, which activates sGC and its downstream pathway, causing the relaxation of blood vessels [ 28 ]. We found that NaHS at concentrations of 3, 50 and 300 μmol/L enhanced the sulfhydration of sGC β1, further proving that NaHS could inhibit sGC β1 activity.…”

“…In this mechanism, heterodimers are formed by disulfide bonds of sGC protein α and β subunits, activating sGC and its downstream pathway, and thus resulting in vasodilatory effects. Similar to sGC, the other key regulatory molecules in sGC/PDE/cGMP/PKG pathway, such as PDE are also constituted of two subunits, regulating its activity by the disulfide bond-dependent heterodimer formation [ 28 ]. Previous studies showed that H 2 S could regulate protein function via modifying the thiol group of protein (-SSH) [ 29 , 30 ].…”

The vasodilatory effect of sulfur dioxide via SGC/cGMP/PKG pathway in association with sulfhydryl-dependent dimerization

“…Consequently, variations in sGC, PKG, and PDE protein contents were a focus of this study. There are two or three subunits in the protein structures of sGC, PKG, and PDE, and research has shown that the combined state of protein subunits, namely, the dimeric form, reflects the level of protein activity (25,42,47). In this study, we found that SO 2 could significantly increase cGMP concentration in the vascular tissue.…”

Tetrandrine prevents monocrotaline-induced pulmonary arterial hypertension in rats through regulation of the protein expression of inducible nitric oxide synthase and cyclic guanosine monophosphate-dependent protein kinase type 1

“…PKG has feedback regulation of sGC, can stimulate phosphodiesterase 5, can increase the hydrolysis of cGMP, and finally can reduce the concentration of cGMP. 26 PKG has two subtypes, PKG-1 and PKG-2, and they are distributed in different tissue. PKG-1 is mainly located in the cytoplasmic matrix and highly expressed in SMCs including vascular SMCs, platelets, fiber cells, and some white blood cells; little is expressed in vascular endothelial cells.…”