NYMC Faculty Publications

Roles for Cytosolic NADPH Redox in Regulating Pulmonary Artery Relaxation by Thiol Oxidation-Elicited Subunit Dimerization of Protein Kinase G1α

Author Type(s)

Faculty

DOI

10.1152/ajpheart.01010.2011

Journal Title

American Journal of Physiology. Heart and Circulatory Physiology

First Page

330

Last Page

343

Document Type

Article

Publication Date

8-1-2013

Department

Physiology

Keywords

Animals, Cattle, Cell Adhesion Molecules, Cell Hypoxia, Cyclic GMP-Dependent Protein Kinase Type I, Cytosol, Enzyme Activation, Enzyme Inhibitors, Glucosephosphate Dehydrogenase, Guanylate Cyclase, Microfilament Proteins, NADPH Oxidases, Organoids, Oxidation-Reduction, Peroxiredoxins, Phosphoproteins, Phosphorylation, Protein Multimerization, Protein Subunits, Pulmonary Artery, RNA Interference, Receptors, Cytoplasmic and Nuclear, Signal Transduction, Soluble Guanylyl Cyclase, Sulfhydryl Compounds, Thioredoxin Reductase 1, Thioredoxins, Tissue Culture Techniques, Transfection, Vasodilation, Vasodilator Agents, Vasodilator-Stimulated Phosphoprotein

Disciplines

Medicine and Health Sciences

Abstract

The activity of glucose-6-phosphate dehydrogenase (G6PD) appears to control a vascular smooth muscle relaxing mechanism regulated through cytosolic NADPH oxidation. Since our recent studies suggest that thiol oxidation-elicited dimerization of the 1α form of protein kinase G (PKG1α) contributes to the relaxation of isolated endothelium-removed bovine pulmonary arteries (BPA) to peroxide and responses to hypoxia, we investigated whether cytosolic NADPH oxidation promoted relaxation by PKG1α dimerization. Relaxation of BPA to G6PD inhibitors 6-aminonicotinamide (6-AN) and epiandrosterone (studied under hypoxia to minimize basal levels of NADPH oxidation and PKG1α dimerization) was associated with increased PKG1α dimerization and PKG-mediated vasodilator-stimulated phosphoprotein (VASP) phosphorylation. Depletion of PKG1α by small inhibitory RNA (siRNA) inhibited relaxation of BPA to 6-AN and attenuated the increase in VASP phosphorylation. Relaxation to 6-AN did not appear to be altered by depletion of soluble guanylate cyclase (sGC). Depletion of G6PD, thioredoxin-1 (Trx-1), and Trx reductase-1 (TrxR-1) in BPA with siRNA increased PKG1α dimerization and VASP phosphorylation and inhibited force generation under aerobic and hypoxic conditions. Depletion of TrxR-1 with siRNA inhibited the effects of 6-AN and enhanced similar responses to peroxide. Peroxiredoxin-1 depletion by siRNA inhibited PKG dimerization to peroxide, but it did not alter PKG dimerization under hypoxia or the stimulation of dimerization by 6-AN. Thus regulation of cytosolic NADPH redox by G6PD appears to control PKG1α dimerization in BPA through its influence on Trx-1 redox regulation by the NADPH dependence of TrxR-1. NADPH regulation of PKG dimerization may contribute to vascular responses to hypoxia that are associated with changes in NADPH redox.

Link to Full Text

Share

COinS