Combined modulation of the mesangial machinery for monocyte recruitment by inhibition of NF-kappaB.

The activation of nuclear factor-kappaB (NF-kappaB) is required for the induction of many of the adhesion molecules and chemokines involved in the inflammatory leukocyte recruitment to the kidney. Here we studied the effects of NF-kappaB inhibition on the machinery crucial for monocyte infiltration of the glomerulus during inflammation. In mesangial cells (MC), the protease inhibitors MG-132 and N-alpha-tosyl-L-lysine chloromethyl ketone or adenoviral overexpression of IkappaB-alpha prevented the complete IkappaB-alpha degradation following tumor necrosis factor-alpha (TNF-alpha) stimulation. This resulted in a marked inhibition of TNF-alpha-induced expression of mRNA and protein for the immunoglobulin molecules intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 and the chemokines growth-related oncogene-alpha, monocyte chemoattractant protein-1, interleukin-8, or fractalkine in MC. Finally, the inhibition of IkappaB-alpha degradation or IkappaB-alpha overexpression suppressed the chemokine-induced transendothelial monocyte chemotaxis toward MC and the chemokine-triggered firm adhesion of monocytic cells to MC. The inhibition of NF-kappaB by pharmacological intervention or gene transfer may present a multimodal approach to control the machinery propagating inflammatory recruitment of monocytes during glomerular disease.