Impact of megsin gene transfection on the expression of extracellular signal-regulated protein kinase under high concentration of glucose / 中华肾脏病杂志

ABSTRACT

objective To observe the effects of megsin gene transfection on glomerular mesangial cells(GMCs)and the expression of platelet-derived growth factor-BB(PDGF-BB),phosphorylated extracellular signal-regulated protein kinase(pERK1/2),transforming growth factor β1 (TGF-β1)and type Ⅳ collagen under high concentration of glucose,and to investigate the impact of megsin gene transfection on the extracellular signal-regulated protein kinase (ERK)siginal pathway. Methods Cultured mesangial cells were divided into seven groupslow glucose group (group A,5.5 mmol/L),high glucose group(group B,30 mmol/L),high glucose plus empty vector group (group C), high glucose plus megsin expression plasmid group (group D), high glucose plus megsin expression plasmids plus U0126 group (group E), high glucose plus megsin siRNA expression plasmids group (group F) and low glucose plus mannitol (24.5 mmol/L,group G). The expressions of megsin, PDGF-BB, pERK1/2, TGF-β1, as well as type Ⅳ collagen in GMCs of each group were detected by Western blotting, after being cultured for 12, 24 and 48 hours respectively. The concentration of type Ⅳ collagen in cell supernatant was measured by radioimmunochemistry. Results Compared with group A, the expression of megsin was increased in GMCs under high glucose medium, with an increase of PDGF-BB, pERK1/2, TGF-β1 in GMCs and type Ⅳ collagen in the supernatants (P＜0.05, respectively). The expression of above indices was in time-dependant manner. The over expression of megsin in exposure to high up-regulated the expression of PDGF-BB, pERK1/2, TGF-β1 and type Ⅳ collagen(P＜0.05, respectively). Compared with group D, the application of U0126 (pERK1/2 inhibitor) had no significant effect on the expression of megsin and PDGF-BB(P＞0.05, respectively). However, the expression of pERK 1/2,TGF-β1 and type Ⅳ collagen were obviously decreased (P＜0.05, respectively). Dowa-regulated expression of megsin by siRNA transfection decreased the expression of PDGF-BB, pERK1/2, TGFβ1 and type Ⅳ collagen(all P＜0.05). Conclusions The expression of megsin and PDGF-BB in GMCs with transfected megsin gene in high glucose medium is increased, possibly in a way of activating ERK signal pathway to some extent that boosts both the expression of TGF-β1 and the production of type Ⅳ collagen. The transfection of megsin siRNA inhibits the expression of obove indices, which probably contributes to the development of diabetic nephropathy.