Angiotensin Ⅱ promotes the expression of glomerular IQGAP1 and apoptosis of glomerular cells / 中华肾脏病杂志

ABSTRACT

Objective To evaluate the effects of Ang Ⅱ on the expression of IQ domain GTPase-activating protein1 (IQGAP1) and apoptosis of glomerular cells,and to explore the role of IQGAP1 in Ang Ⅱ-induced apoptosis of glomerular cells.Methods Thirty-six male Wistar rats were randomly assigned to receive either saline or Ang Ⅱ by osmotic mini-pump,or be used as normal control.The systolic blood pressure and proteinuria were measured at day 7,14,21,28.After the animals were sacrificed at day 14,28 respectively,the kidneys were collected.Renal pathological change,glomerular cell apoptosis were observed.The expression of glomerular IQGAP1 was assessed by immunohistochemistry,immunofluorescence and Western blotting.The activation of caspase-3 and phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2) were determined by Western blotting.Results Ang Ⅱ-infused rats developed significant hypertension and marked proteinuria.Mild glomerular mesangial cell proliferation and mesangial matrix increase were also observed in Ang Ⅱ-infused rats.The number of apoptotic glomerular cells in Ang Ⅱ-infused rats was significantly more than that in normal control (P ＜ 0.05).The expression of IQGAP1 in glomeruli distributed linearly along the capillary loops.Ang Ⅱ infusion up-regulated the expression of glomerular IQGAP1,which had an significantly positive correlation with activation of caspase-3(r =0.689,P ＜ 0.05) and phosphorylation of ERK1/2 (r =0.658,P ＜ 0.05).Conclusion The enhanced expression of IQGAP1 may be involved in Ang Ⅱ-induced glomerular cells apoptosis via activation of ERK1/2 signaling pathway.