Advanced glycation end product-induced activation of NF-kappaB is suppressed by alpha-lipoic acid in cultured endothelial cells.
Diabetes
; 46(9): 1481-90, 1997 Sep.
Article
em En
| MEDLINE
| ID: mdl-9287050
ABSTRACT
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 oxidative stress led to the activation of the transcription factor NF-kappaB and thus promoted the upregulation of various NF-kappaB-controlled genes, including endothelial tissue factor. Supplementation of the cellular antioxidative defense with the natural occurring antioxidant alpha-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-kappaB activation was also reduced in a time- and dose-dependent manner as long as alpha-lipoic acid was added at least 30 min before AGE albumin stimulation. Inhibition was not due to physical interactions with protein DNA binding, since alpha-lipoic acid, directly included into the binding reaction, did not prevent binding activity of recombinant NF-kappaB. Western blots further demonstrated that alpha-lipoic acid inhibited the release and translocation of NF-kappaB from the cytoplasm into the nucleus. As a consequence, alpha-lipoic acid reduced AGE albumin-induced NF-kappaB 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 alpha-lipoic acid reduces AGE albumin-induced endothelial dysfunction in vitro.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tromboplastina
/
Endotélio Vascular
/
NF-kappa B
/
Ácido Tióctico
/
Produtos Finais de Glicação Avançada
/
Antioxidantes
Limite:
Humans
Idioma:
En
Ano de publicação:
1997
Tipo de documento:
Article