[Effect of transforming growth factor beta1/Smad signaling pathway on the expression and enzymatic activity of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 in cultured rat mesangial cells].

OBJECTIVE: To explore the effect of transforming growth factor (TGF) beta1/Smad signaling pathway on the expression and enzymatic activity of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) in cultured rat mesangial cells (MsC). METHODS: Lipofectin method was used to transfect Smad 2, Smad 3 and Smad 7 vectors into MsC; and immunofluorescence, RT-PCR and Western blot analysis were used to detect their transfection efficiency. The expression and enzymatic activity of MMP-2 and TIMP-2 were determined by Western blot, zymography or reverse zymography assay. RESULTS: MsC transfected with Smad 2 gene showed slightly increased expression and enzymatic activity of both MMP-2 and TIMP-2, which was more obvious upon stimulation by TGF-beta1. MsC transfected with Smad 3 gene showed a slight upregulation of TIMP-2 expression and its enzymatic activity, which was enhanced after TGF-beta1 stimulation. There was however no change in MMP-2 expression and its enzymatic activity. On the other hand, MsC transfected with Smad 7 gene showed a decrease in MMP-2 and TIMP-2 expression and enzymatic activity, which was especially obvious after stimulation by TGF-beta1. CONCLUSIONS: TGF-beta1/Smad signaling pathway may play an important role in the pathogenesis of glomerulosclerosis, probably via MMP-2 and TIMP-2 expression and the associated enzymatic activity.