Peroxide generation by p47 phox -Src activation of Nox2 has a key role in protein kinase C-induced arterial smooth muscle contraction

• Published in: American journal of physiology. Heart and circulatory physiology 2009-04, Vol.296 (4), p.H1048-H1057
• Main Authors: Gupte, Sachin A., Kaminski, Pawel M., George, Shimran, Kouznestova, Lioubov, Olson, Susan C., Mathew, Rajamma, Hintze, Thomas H., Wolin, Michael S.
• Format: Article
• Language: English
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00491.2008

Protein kinase C (PKC) stimulation of NAD(P)H oxidases (Nox) is an important component of multiple vascular disease processes; however, the relationship between oxidase activation and the regulation of vascular smooth muscle contraction by PKC remains poorly understood. Therefore, we examined the signaling cascade of PKC-elicited Nox activation and the role of superoxide and hydrogen peroxide in mediating PKC-induced vascular contraction. Endothelium-denuded bovine coronary arteries showed a PKC-dependent basal production of lucigenin (5 μM)-detected Nox oxidase-derived superoxide, which was stimulated fourfold by PKC activation with 10 μM phorbol 12,13-dibutyrate (PDBu). PDBu appeared to increase superoxide generation by Nox2 through both p47 phox and peroxide-dependent Src activation mechanisms based on the actions of inhibitors, properties of Src phosphorylation, and the loss of responses in aorta from mice deficient in Nox2 and p47 phox . The actions of inhibitors of contractile regulating mechanisms, scavengers of superoxide and peroxide, and responses in knockout mouse aortas suggest that a major component of the contraction elicited by PDBu appeared to be mediated through peroxide derived from Nox2 activation stimulating force generation through Rho kinase and calmodulin kinase-II mechanisms. Superoxide generated by PDBu also attenuated relaxation to nitroglycerin. Peroxide-derived from Nox2 activation by PKC appeared to be a major contributor to the thromboxane A 2 receptor agonist U46619 (100 nM)-elicited contraction of coronary arteries. Thus a p47 phox and Src kinase activation of peroxide production by Nox2 appears to be an important contributor to vascular contractile mechanisms mediated through activation of PKC.