Interleukin-1 and glomerular mesangial cells.

Our previous in vitro study demonstrated that interleukin-1 (IL-1) stimulates gene expression and production of leukocyte chemotactic factors, colony-stimulating factors and interleukin-6 in human mesangial cells in culture. Here we investigated whether IL-1 regulates its own gene expression in human mesangial cells. Northern blot experiments showed that IL-1 induced IL-1 mRNA expression in a dose-dependent manner. The action of IL-1 on mesangial cells was mediated through the IL-1 receptor type I, which is constitutively expressed by mesangial cells. Recombinant IL-1 receptor antagonist blocked the IL-1 mRNA as well as interleukin-6 and interleukin-8 gene expression induced by IL-1. These data support the crucial role played by IL-1 in regulating mesangial cell cytokine genes within the glomerulus during immunological or inflammatory processes.