Effects of silence information regulator 7 on proliferation and apoptosis of mouse renal podocytes under high glucose environment

Abstract

Objective: To investigate the effects and its mechanisms of silence information regulator 7(SIRT7)on mouse renal podocytes proliferation and apoptosis under high glucose environment. Methods: Mouse renal podocytes cultured with high glucose and treated with different methods were divided into the following groups:control group(Control),high glucose group(HG),high glucose+transfecting with SIRT7 overexpression vetor(pcDNA3.1-SIRT7) group(SIRT7 OE+HG),high glucose+transfecting with the negative control vetor(pcDNA3.1)group(SIRT7 OE-NC+HG),high glucose+transfecting with small interfering RNA-SIRT7 (siRNA-SIRT7) group (siRNA-SIRT7+HG), high glucose+ transfecting with siRNA-SIRT7 control group (siRNA-SIRT7-NC+ HG). Viability of proliferation was examined by CCK-8 method.Rate of apoptosis was detected by flow cytometry. The level of SIRT7 mRNA expression was measured by qRT-PCR. Western blot was performed to detect the protein expression of Nephrin and key factors of Wnt/β-catenin signaling pathway. Results: The CCK-8 result showed that,compared with control group, the proliferative activity of mouse renal podocytes in HG group was decreased (P＜0.05). After transfected with SIRT7 overexpression vetor or small interfering RNA-SIRT7,compared to HG group,the cell proliferation activity was further decreased in siRNA-SIRT7 group(P＜0.05),but it was enhanced in SIRT7 OE+HG group (P＜0.05). The results of flow cytometry showed that compared with the control group, the apoptosis rate of cells in the HG group was increased (P＜0.05). Compared with the HG group, the apoptosis rate of cells in the siRNA SIRT7+HG group was increased significantly(P＜0.05), while that in the SIRT7 OE+HG group was decreased (P＜0.05). Compared with control group,the expressions of Nephrin, Wnt5a and β-catenin were inhibited in HG group (P＜0.05). compared to HG group,siRNA-SIRT7 could down-regulate the expression levels of Nephrin, Wnt5a and β-catenin in siRNA-SIRT7 group (P＜0.05), SIRT7 overexpression could up-regulate the expression levels of Nephrin, Wnt5a and β-catenin in SIRT7 OE+HG group (P＜0.05). Conclusion: The findings suggest that high glucose environment is an important factor to inhibit the proliferation and induce apoptosis of mouse renal podocytes.Overexpression of SIRT7 can reverse the effects by activating Wnt/β-catenin signaling pathway and up-regulating β-catenin expression.