Glucose down-regulation of cGMP-dependent protein kinase I expression in vascular smooth muscle cells involves NAD(P)H oxidase-derived reactive oxygen species

Shu Liu, Xueying Ma, Mingcui Gong, Lihua Shi, Thomas Lincoln, Shuxia Wang

Research output: Contribution to journalArticlepeer-review

75 Scopus citations

Abstract

Reduced levels of cGMP-dependent protein kinase I (PKG-I) in vasculature have been shown to contribute to diabetic vascular dysfunctions. However, the underlying mechanisms remain unknown. In this report, using primary rat aortic smooth muscle cells (VSMC), we investigated the mechanisms of glucose-mediated regulation of PKG-I expression. Our data showed that high glucose (30 mM glucose) exposure significantly reduced PKG-I production (protein and mRNA levels) as well as PKG-I activity in cultured VSMC. Glucose-mediated decreases in PKG-I levels were inhibited by a superoxide scavenger (tempol) or NAD(P)H oxidase inhibitors (diphenylene iodonium or apocynin). High glucose exposure time-dependently increased superoxide production in VSMC, which was abolished by tempol or apocynin treatment, but not by other inhibitors of superoxide-producing enzymes (L-NAME, rotenone, or oxypurinol). Total protein levels and phosphorylated levels of p47phox (an NADPH oxidase subunit) were increased in VSMC after high glucose exposure. Transfection of cells with siRNA-p47phox abolished glucose-induced superoxide production and restored PKG-I protein levels in VSMC. Treatment of cells with PKC inhibitor prevented glucose-induced p47phox expression/phosphorylation and superoxide production and restored the PKG-I levels. Decreased PKG-I protein levels were also found in femoral arteries from diabetic mice, which were associated with the decreased DEA-NONOate-induced vasorelaxation. Taken together, the present results suggest that glucose-mediated down-regulation of PKG-I expression in VSMC occurs through PKC-dependent activation of NAD(P)H oxidase-derived superoxide production, contributing to diabetes-associated vessel dysfunctions.

Original languageEnglish
Pages (from-to)852-863
Number of pages12
JournalFree Radical Biology and Medicine
Volume42
Issue number6
DOIs
StatePublished - Mar 15 2007

Bibliographical note

Funding Information:
This work was supported by American Heart Association SDG Grant 0435132N (to S.W.), NIH HL 67284 (to M.G.), and NIH HL 53426 (to T.L.).

Keywords

  • Free radicals
  • Glucose
  • NAD(P)H oxidase
  • Oxidative stress
  • PKG-I

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)

Fingerprint

Dive into the research topics of 'Glucose down-regulation of cGMP-dependent protein kinase I expression in vascular smooth muscle cells involves NAD(P)H oxidase-derived reactive oxygen species'. Together they form a unique fingerprint.

Cite this