Suppressor of cytokine signaling-1 inhibits high glucose-induced expression of monocyte chemoattractant protein-1 in glomerular mesangial cells / 中华肾脏病杂志

ABSTRACT

Objective To investigate the effect of suppressor of cytokine signaling-1 (SOCS-1)on expression of monocyte chemoattractant protein-1 (MCP-1)in human glomerular mesangial cells (HMCs) under high concentration of glucose. Methods Stable transfections of HMC with pCR3.1 vector and pCR3. 1-SOCS-1 were performed with hpofectamine 2000, and cells were selected with geneticin. Cells were stimulated with low glucose (LG, 5.5 mmol/L), high glucose (HG, 30 mmol/L), LG plus mannitol (24.5 mmol/L) and AG490 (10 μmol/L). The protein expression levels of SOCS-1, signal transducer and activators of transcription 1,3 (STAT1, STAT3),p-STAT1 and p-STAT3 were observed by Western blotting. The protein synthesis of MCP-1, FN and type Ⅳ collagen in the supernatants of the HMCs were detected by ELISA and radioimmunoassay. The expression level of SOCS-1 and MCP-1 mRNA was measured by BT-PCR.Results HG induced the expression of SOCS-1 protein and mRNA in HMCs in time-dependant manner, peaked at 4 h, and gradually decreased to baseline at 24 h. Compared with low glucose control group, the phosphorylation levels of STAT1 and STAT3 and the expression of MCP-1 mRNA [(0.39±0.05) vs (0.16±0.02)]were significantly increased in HMCs under high glucose medium (P ＜0.01 ). Exposure of HMCs to high glucose conditions showed high concentration of MCP-1 [(459±67) ng/L vs (241±19) ng/L], fibronectin [(5.84±0.61) mg/L vs (3.41±0.31) mg/L]and type Ⅳ collagen [(16.45±2.30) μg/L vs (9.56±1.52) μg/L]in the supernatants (all P＜0.01).Overexpression of SOCS-1 inhibited the phosphorylation levels of STAT1 and STAT3 and the expression of MCP-1 mRNA [(0.34±0.04) vs (0.42±0.05)]in HMCs under high glucose condition (all P＜0.05). Compared with vector control group, the concentration of MCP-1 [(387±47) ng/L vs (463±56) ng/L], fibronectin [(4.61±0.57) mg/L vs (5.76±0.74) mg/L]and type Ⅳ collagen [(13.4±2.32) μg/L vs (17.1±2.57) μg/L]was decreased in supernatants of HMCs with SOCS-1 overexpression (all P＜0.05). Compared with HG group, the expression of MCP-1 mRNA (0.31±0.04) and the concentration of MCP-1 [(361±53) ng/L], FN [(5.46±0.71) mg/L]and type Ⅳ collagen [(15.2±1.97) μg/L]in supernatants were decreased in HMCs treated with AG490.Conclusion Overexpression of SOCS-1 inhibits overproduction of MCP-1 and ECM proteins in HMCs under high glucose conditions, which may be partly by regulating the phosphoryhtion of STAT1 and STAT3.