Au-Yeung KKW, Woo CWH, Sung FL, Yip JCW, Siow YL, O K. Hyperhomocysteinemia activates nuclear factor-kappaB in endothelial cells via oxidative stress.
Circ Res 2003;
94:28-36. [PMID:
14630727 DOI:
10.1161/01.res.0000108264.67601.2c]
[Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases. Our previous studies demonstrated an important interaction between nuclear factor-kappaB (NF-kappaB) activation and homocysteine (Hcy)-induced chemokine expression in vascular smooth muscle cells and macrophages. The objective of the present study was to investigate the in vivo effect of hyperhomocysteinemia on NF-kappaB activation and the underlying mechanism of Hcy-induced NF-kappaB activation in endothelial cells. Hyperhomocysteinemia was induced in Sprague-Dawley rats after 4 weeks of a high-methionine diet. The activated form of NF-kappaB and increased level of superoxide anions were detected in the endothelium of aortas isolated from hyperhomocysteinemic rats. The underlying mechanism of Hcy-induced NF-kappaB activation was investigated in human umbilical cord vein endothelial cells and in human aortic endothelial cells. Incubation of cells with Hcy (100 micromol/L) activated IkappaB kinases (IKKalpha and IKKbeta), leading to phosphorylation and subsequent degradation of IkappaBalpha. As a consequence, NF-kappaB nuclear translocation, enhanced NF-kappaB/DNA binding activity, and increased transcriptional activity occurred. Additional analysis revealed a marked elevation of superoxide anion levels in Hcy-treated cells. Treatment of cells with a superoxide anion scavenger (polyethylene glycol-superoxide dismutase) or IkappaB kinase inhibitor (prostaglandin A(1)) could prevent Hcy-induced activation of IKK kinases and NF-kappaB in endothelial cells. In conclusion, these results suggest that Hcy-induced superoxide anion production may play a potential role for NF-kappaB activation in the early stages of atherosclerosis in the vascular wall via activation of IkappaB kinases.
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