Nuclear factor-kappa B mediates induction of vascular cell adhesion molecule-1 in glomerular mesangial cells

Cultured glomerular mesangial cells (GMCs) can be activated at the transcriptional level by a variety of physiologically relevant factors including cytokines, endotoxin and glycosylated end products. The mechanism with which the signal is transduced from the membrane to the nucleus of these cells is largely unclear. In vascular endothelial cells, the signal transduction pathway involves activation of the pleuripotent transcription factor, NF-kappa B, and leads to increased expression of a variety of genes including vascular cell adhesion molecule-1 (VCAM-1). Here, we demonstrate that TNF-alpha and IL-1 beta transiently induced VCAM-1 mRNA expression in a time dependent manner. TNF-alpha also induced the specific interaction of proteins from GMC nuclei with an oligonucleotide bearing the NF-kappa B binding sites in the VCAM-1 promoter. Electrophoretic mobility shift and supershift analysis indicated that the p65 subunit of NF-kappa B is a component of this induced complex. Finally, reporter activity driven by a VCAM-1 promoter-chloramphenicol acetyltransferase reporter construct increased 8-10 fold following TNF-alpha incubation, or p65 cotransfection. Thus, the p65 subunit of NF-kappa B is activated in GMCs exposed to cytokine and can mediate induction of gene expression.