Advanced glycation end product-induced activation of NF-κB is suppressed by α-lipoic acid in cultured endothelial cells

• Published in: Diabetes (New York, N.Y.) Vol. 46; no. 9; pp. 1481 - 1490
• Main Authors: BIERHAUS, A, CHEVION, S, WAHL, P, ZIEGLER, R, NAWROTH, P. P, CHEVION, M, HOFMANN, M, QUEHENBERGER, P, ILLMER, T, LUTHER, T, BERENTSHTEIN, E, TRITSCHLER, H, MÜLLER, M
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01-09-1997
• Subjects: Antioxidants; Antioxidants (Nutrients); Associated diseases and complications; Biological and medical sciences; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Endothelium; Medical sciences; Physiological aspects; Endocrinopathy; Lipoic acid; Endothelial cell; Pathogenesis; Diabetes mellitus; Reaction product; Tissue factor; Ox; Antioxidant; Gene expression; In vitro; Glycation; Vascular disease; Vertebrata; Mammalia; Aorta; Complication; Circulatory system; Artiodactyla; Ungulata
• ISSN: 0012-1797; 1939-327X
• DOI: 10.2337/diab.46.9.1481

Depletion of cellular antioxidant defense mechanisms and the generation of oxygen free radicals by advanced glycation end products (AGEs) have been proposed to play a major role in the pathogenesis of diabetic vascular complications. Here we demonstrate that incubation of cultured bovine aortic endothelial cells (BAECs) with AGE albumin (500 nmol/l) resulted in the impairment of reduced glutathione (GSH) and ascorbic acid levels. As a consequence, increased cellular oxida-tive stress led to the activation of the transcription factor NF-KB and thus promoted the upregulation of various NF-KB-controlled genes, including endothelial tissue factor. Supplementation of the cellular antiox-idative defense with the natural occurring antioxidant α-lipoic acid before AGE albumin induction completely prevented the AGE albumin–dependent depletion of reduced glutathione and ascorbic acid. Electrophoretic mobility shift assays (EMSAs) revealed that AGE albumin-mediated NF-KB activation was also reduced in a time- and dose-dependent manner as long as α-lipoic acid was added at least 30 min before AGE albumin stimulation. Inhibition was not due to physical interactions with protein DNA binding, since α-lipoic acid, directly included into the binding reaction, did not prevent binding activity of recombinant NF-KB. Western blots further demonstrated that α-lipoic acid inhibited the release and translocation of NF-KB from the cytoplasm into the nucleus. As a consequence, α-lipoic acid reduced AGE albumin-induced NF-KB mediated transcription and expression of endothelial genes relevant in diabetes, such as tissue factor and endothelin-1. Thus, supplementation of cellular antioxidative defense mechanisms by extracellularly administered α-lipoic acid reduces AGE albumin-induced endothelial dysfunction in vitro.