| Background:Glomerular sclerosis is characterized by mesangial cell proliferation and progressive extracellular matrix (ECM) accumulation. There is increasing evidence suggesting that CCN3 may act as an endogenous negative regulator of the ECM and fibrosis. However, the exact mechanistic role of CCN3 in the accumulation of ECM is still unknown. The aim of present study was to investigate whether CCN3 mediates TGF-β1-induced formation of the extracellular matrix in human mesangial cells (HMCs).Methods:After pretreatment for 1 hour (h) with different doses of exogenous CCN3 (5 ng/ml, 50 ng/ml, or 500 ng/ml), HMCs were incubated in RPMI-1640 containing TGF-β1 (2 ng/ml) for 24 h. The expression of fibronectin (FN), type I collagen (COLI), matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 were detected by RT-PCR and Western blot. To gain further insight into the effects of CCN3 on the formation of the ECM, we transfected HMCs with pcDNA3.1 (+)-CCN3 and then exposed the cells to TGF-β1 (2 ng/ml). The expression of FN and COLI was detected by RT-PCR, Western blot and immunofluorescence microscopy. The expression of MMP-2, MMP-9 and TIMP-1 was detected by RT-PCR and Western blot.Results:It was shown that TGF-β1 significantly decreased the expression of CCN3 in a dose-and time-dependent manner (P<0.05) when analyzed by Western blot. Either exogenous CCN3 or endogenous CCN3 overexpression inhibited TGF-β1-induced increases in FN and COLI (P<0.05) expression. The expression of MMP-2 and MMP-9, as detected by RT-PCR and Western blot, was significantly increased compared with the TGF-β1 alone group (P< 0.05). Furthermore, we observed that the expression of TIMP-1 was markedly inhibited by CCN3 compared with its expression in the TGF-β1 alone group (P<0.05).Conclusion:CCN3 reduced the production of ECM and promoted TGF-β1-induced degradation of the ECM. CCN3 represents a potentially novel therapeutic tool to alleviate glomerulosclerosis. |
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