Wuensch T, Thilo F, Krueger K, Scholze A, Ristow M, Tepel M. High glucose-induced oxidative stress increases transient receptor potential channel expression in human monocytes.
Diabetes 2010;
59:844-9. [PMID:
20068131 PMCID:
PMC2844832 DOI:
10.2337/db09-1100]
[Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE
Transient receptor potential (TRP) channel-induced cation influx activates human monocytes, which play an important role in the pathogenesis of atherosclerosis. In the present study, we investigated the effects of high glucose-induced oxidative stress on TRP channel expression in human monocytes.
RESEARCH DESIGN AND METHODS
Human monocytes were exposed to control conditions (5.6 mmol/l d-glucose), high glucose (30 mmol/l d-glucose or l-glucose), 100 micromol/l peroxynitrite, or high glucose in the presence of the superoxide dismutase mimetic tempol (100 micromol/l). TRP mRNA and TRP protein expression was measured using quantitative real-time RT-PCR and quantitative in-cell Western assay, respectively. Calcium influx and intracellular reactive oxygen species were measured using fluorescent dyes.
RESULTS
Administration of high d-glucose significantly increased reactive oxygen species. High d-glucose or peroxynitrite significantly increased the expression of TRP canonical type 1 (TRPC1), TRPC3, TRPC5, TRPC6, TRP melastatin type 6 (TRPM6), and TRPM7 mRNA and TRPC3 and TRPC6 proteins. High d-glucose plus tempol or high l-glucose did not affect TRP expression. Increased oxidative stress by lipopolysaccharide or tumor necrosis factor-alpha increased TRP mRNA expression, whereas the reduction of superoxide radicals using diphenylene iodonium significantly reduced TRP mRNA expression. Increased TRPC3 and TRPC6 protein expression was accompanied by increased 1-oleoyl-2-acetyl-sn-glycerol-induced calcium influx, which was blocked by the TRPC inhibitor 2-aminoethoxydiphenylborane. TRPC6 mRNA was significantly higher in monocytes from 18 patients with type 2 diabetes compared with 28 control subjects (P < 0.05).
CONCLUSIONS
High d-glucose-induced oxidative stress increases TRP expression and calcium influx in human monocytes, pointing to a novel pathway for increased activation of monocytes and hence atherosclerosis in patients with diabetes.
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