Open AccessHigh glucose-induced IKK-Hsp-90 interaction contributes to endothelial dysfunction
Author(s) -
Sumathy Mohan,
Ryszard Konopiński,
Bo Yan,
Victoria E. Centonze,
Mohan Natarajan
Publication year - 2009
Publication title -
american journal of physiology. cell physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.432
H-Index - 181
eISSN - 1522-1563
pISSN - 0363-6143
DOI - 10.1152/ajpcell.00575.2007
Subject(s) - enos , nitric oxide , endothelial dysfunction , kinase , nitric oxide synthase , chemistry , iκb kinase , nitric oxide synthase type iii , pharmacology , biology , microbiology and biotechnology , biochemistry , endocrinology , nf κb , apoptosis
A decline in the bioavailability of nitric oxide (NO) that causes endothelial dysfunction is a hallmark of diabetes. The availability of NO to the vasculature is regulated by endothelial nitric oxide synthase (eNOS) activity and the involvement of heat shock protein-90 (Hsp-90) in the regulation of eNOS activity has been demonstrated. Hsp-90 has been shown to interact with upstream kinases [inhibitor kappaB kinases (IKK)alpha, beta, and gamma] in nonvascular cells. In this study, we have investigated the interaction of Hsp-90-IKKbeta in endothelial cells under conditions of high glucose (HG) as a possible mechanism that diminishes Hsp-90-eNOS interaction, which could contribute to reduced bioavailability of NO. We report for the first time that IKKbeta interacts with Hsp-90, and this interaction is augmented by HG in vascular endothelial cells. HG also augments transcriptional (3.5 +/- 0.65-fold) and translational (1.97 +/- 0.17-fold) expression as well as the catalytic activity of IKKbeta (2.45 +/- 0.4-fold). Both IKKbeta and eNOS could be coimmunoprecipitated with Hsp-90. Inhibition of Hsp-90 with geldanamycin (2 microM) or Radicicol (20 microM) mitigated (0.45 +/- 0.04-fold and 0.93 +/- 0.16-fold, respectively) HG induced-IKKbeta activity (2.5 +/- 0.42-fold). Blocking of IKKbeta expression by IKK inhibitor II (15 microM wedelolactone) or small interferring RNA (siRNA) improved Hsp-90-eNOS interaction and NO production under conditions of HG. These results illuminate a possible mechanism for the declining eNOS activity reported under conditions of HG.