N-acetyl cysteine blocks mesangial VCAM-1 and NF-kappa B expression in vivo

Inducible vascular cell adhesion molecule-1 (VCAM-1) in glomerular mesangial cells (GMC) exposed to lipopolysaccharide (LPS) in vitro involves the activation of nuclear factor-kappa B (NF-kappa B) and its interaction with the proximal VCAM-1 promoter. We used a murine model to assess the effect of the antioxidant, N-acetyl cysteine on GMC activation in vivo. Single intraperitoneal administration of N-acetyl cysteine completely suppressed LPS-induced VCAM-1 expression on the GMC surface. When an oligonucleotide spanning the NF-kappa B binding region of the VCAM-1 promoter was incubated with extracts from the renal cortex of LPS-treated animals, a single nucleoprotein complex formed. This complex was composed of p50 and p65, but not p52, c-Rel, or RelB, and its formation was dramatically inhibited by pretreatment with N-acetyl cysteine, D,L-Buthionine-[S,R]-sulfoximide, a compound that depletes glutathione, augmented VCAM-1 expression inducible with a suboptimal amount of LPS to levels comparable with using 50 micrograms of LPS alone, D,L-Buthionine-[S,R]-sulfoximide also potentiated the p50-p65 binding activity induced with a suboptimal amount of LPS. These data provide a redox-sensitive, transcriptional link between NF-kappa B and VCAM-1 in GMC in vivo and implicate oxidative stress as an important regulatory signal in the pathogenesis of glomerular mesangial cell disorders.