Silica induces nuclear factor-κB activation through TAK1 and NIK in Rat2 cell line

Abstract Silica has been known to be a factor in acute cell injury and chronic pulmonary fibrosis. In Rat2 fibroblasts, silica induced the activation of nuclear factor-kappa B (NF-κB), which plays a crucial role in regulating the expression of many genes involved in the subsequent inflammatory response. In addition, we observed that transforming growth factor-β activated kinase 1 (TAK1) and NF-κB-inducing kinase (NIK) were involved in silica-mediated NF-κB activation in Rat2 cells. The dominant negative mutant forms of TAK1 and NIK inhibited the silica-induced NF-κB activation in Rat2 cells. Furthermore, we demonstrated that endogenous TAK1 is phosphorylated in silica-stimulated Rat2 cells. These results indicate that TAK1 functions as a critical mediator in the silica-induced signaling pathway.