Abstract:

Objective   To investigate the role of mRNA stabilizing factor Human-Antigen R(HuR) in angiotensinⅡ(AngII)-stimulated cyclinD1 over-expression in cultured human mesangial cells. Methods   Human mesangial cells cultured in vitro were divided into 0A group,3A group, 6A group, 9A group and 24A group according to the time gradient of angiotensin II management(0h,3h,6h,9h,and 24h). Cell cycle was detected by flow cytometry and subcellular localization of  HuR protein was determined by immunochemistry. Total cyclinD1 protein ,cytoplasmic and total HuR protein expression were detected by Western blot and total cyclinD1  mRNA level was determined by RT-PCR. Using RNA interference technology to down regulate HuR protein level, we surveyed protective effect of angiotensinⅡ on total cyclinD1 protein expression. Results   Compared with 0A group, there was a marked increase in mesangial cells proliferation in 24A group(P<0.05). HuR protein shifted from nucleus to cytoplasm, especially in 3A group. There was no significant variation of total HuR protein expression but an increase in cytoplasmic HuR protein especially in 3A group(P<0.05). An increase in total cyclinD1 protein expression was observed in 24A group(P<0.05), but no change in RNA level. Compared with transfection before, there was a marked decrease in cytoplasmic HuR protein expression in 3A group(P<0.05) and total cyclinD1 protein expression in 24A group(P<0.05), but no change in cyclinD1 RNA level. Conclusion   ①AngⅡ induces proliferation of human mesangial cells.②HuR protein shifts from nucleus to cytoplasm induced by AngⅡ.③HuR protein is involved in the expression of cyclinD1 protein with AngⅡ stimulation.

Key words:  Human mesangial cells； Angiotensin Ⅱ; HuR protein; CyclinD1 protein; RNA interference technology