Resistance to the nitric oxide/cyclic guanosine 5′-monophosphate/ protein kinase G pathway in vascular smooth muscle cells from the obese zucker rat, a classical animal model of insulin resistance: Role of oxidative stress

I. Russo, P. Del Mese, G. Doronzo, L. Mattiello, M. Viretto, A. Bosia, G. Anfossi, Mariella Trovati

Research output: Contribution to journalArticlepeer-review

Abstract

Some in vivo and ex vivo studies demonstrated a resistance to the vasodilating effects of nitric oxide (NO) in insulin-resistant states and, in particular, obese Zucker rats (OZR). To evaluate the biochemical basis of this phenomenon, we aimed to identify defects of the NO/cGMP/cGMP-dependent protein kinase (PKG) pathway in cultured vascular smooth muscle cells (VSMCs) from OZR and lean Zucker rats (LZR) by measuring: 1) NO donor ability to increase cGMP in the absence and presence of inhibitors of soluble guanylate cyclase (sGC) and phosphodiesterases (PDEs); 2) NO and cGMP ability to induce, via PKG, vasodilator-stimulated phosphoprotein (VASP) phosphorylation at serine 239 and PDE5 activity; 3) protein expression of sGC, PKG, total VASP, and PDE5; 4) superoxide anion concentrations and ability of antioxidants (superoxide dismutase-catalase and amifostine) to influence the NO/cGMP/PKG pathway activation; and 5) hydrogen peroxide influence on PDE5 activity and VASP phosphorylation. VSMCs from OZR vs. LZR showed: 1) baseline cGMP concentrations higher, at least in part owing to reduced catabolism by PDEs; 2) impairment of NO donor ability to increase cGMP, even in the presence of PDE inhibitors, suggesting a defect in the NO-induced sGC activation; 3) reduction of NO and cGMP ability to activate PKG, indicated by the impaired ability to phosphorylate VASP at serine 239 and to increase PDE5 activity via PKG; 4) similar baseline protein expression of sGC, PKG, total VASP, and PDE5; and 5) higher levels of superoxide anion. Antioxidants partially prevented the defects of the NO/cGMP/PKG pathway observed in VSMCs from OZR, which were reproduced by hydrogen peroxide in VSMCs from LZR, suggesting the pivotal role of oxidative stress.

Original languageEnglish
Pages (from-to)1480-1489
Number of pages10
JournalEndocrinology
Volume149
Issue number4
DOIs
Publication statusPublished - Apr 2008

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Fingerprint Dive into the research topics of 'Resistance to the nitric oxide/cyclic guanosine 5′-monophosphate/ protein kinase G pathway in vascular smooth muscle cells from the obese zucker rat, a classical animal model of insulin resistance: Role of oxidative stress'. Together they form a unique fingerprint.

Cite this