IQGAP1 Mediates Angiotensin II-Induced Apoptosis of Podocytes via the ERK1/2 MAPK Signaling Pathway
IQGAP1 Mediates Angiotensin II-Induced Apoptosis of Podocytes via the ERK1/2 MAPK Signaling Pathway
复制标题
IQGAP1 通过 ERK1/2 MAPK 信号通路介导血管紧张素 II 诱导的足细胞凋亡
DOI：
10.1159/000355970
复制
发表时间：
2013-01-01
影响因子：
4.2
通讯作者：
Ding, Guohua
中科院分区：
文献类型：
--
作者：
Liu, Yipeng;Liang, Wei;Ding, Guohua
背景/目的：血管紧张素II（AngII）促进足细胞凋亡的机制尚未确定。IQ结构域GTPase-activating protein 1（IQGAP 1）是有丝分裂原活化蛋白激酶（MAPK）信号通路的支架蛋白，在细胞凋亡中发挥重要作用。本研究评估IQGAP 1在AngII诱导的足细胞凋亡中的作用。研究方法：我们将36只雄性Wistar大鼠随机分为生理盐水灌注组、AngII灌注组或正常对照组，并通过末端脱氧核苷酸转移酶介导的dUTP-生物素缺口末端标记（TUNEL）分析和透射电镜分析来测量足细胞凋亡。此外，我们将分化的小鼠足细胞暴露于AngII，然后通过流式细胞术和Hoechst-33258染色评估凋亡。采用Western blotting、real-time PCR和免疫荧光法检测IQGAP 1在体内外的表达。进一步引入IQGAP 1 siRNA和MAPK通路抑制剂，研究IQGAP 1和MAPK信号通路在该过程中的作用。免疫共沉淀法检测ERK 1/2与IQGAP 1的相互作用。结果：AngII在体内外均能促进足细胞凋亡。IQGAP 1在体内呈沿着肾小球毛细血管袢的线状分布，在体外培养的足细胞中，IQGAP 1主要分布于细胞膜和细胞质中。AngII刺激IQGAP 1表达并增加P38、JNK和ERK 1/2的磷酸化。用siRNA敲低IQGAP 1可阻止AngII诱导的足细胞凋亡，并减少AngII诱导的ERK 1/2磷酸化，但对P38、JNK磷酸化无影响。这伴随着ERK 1/2和IQGAP 1之间的相互作用减少。结论：IQGAP 1通过与ERK 1/2信号蛋白相互作用参与AngII诱导足细胞凋亡。
Background/Aims: The mechanism underlying angiotensin II (AngII)-promoted podocyte apoptosis has not been established. IQ domain GTPase-activating protein 1 (IQGAP1) is a scaffolding protein of the mitogen-activated protein kinases (MAPK) signaling pathway, and plays a significant role in apoptosis. The present study evaluates the role of IQGAP1 in AngII-induced podocyte apoptosis. Methods: We randomly assigned 36 male Wistar rats to a normal saline-infused group, an AngII-infused group, or a normal control group, and measured podocyte apoptosis by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay and transmission electron microscopic analysis. In addition, we exposed differentiated mouse podocytes to AngII and then assessed apoptosis by flow cytometry and Hoechst-33258 staining. Expression of IQGAP1 was measured by Western blotting, real-time PCR and immunofluorescence assay in vivo and in vitro. IQGAP1 siRNA and MAPK pathway inhibitors were further introduced to investigate the role of IQGAP1 and MAPK signaling in the process. Coimmunoprecipitation was used to evaluate the interaction between ERK1/2 and IQGAP1. Results: AngII promoted podocyte apoptosis in vivo and in vitro. IQGAP1 had a linear distribution along the capillary loops of glomeruli in vivo, and was in the cellular membrane and cytoplasm of cultured podocytes. AngII stimulated IQGAP1 expression and increased phosphorylation of P38, JNK, and ERK1/2. Knockdown of IQGAP1 with siRNA prevented AngII-induced apoptosis of podocytes and reduced AngII-induced phosphorylation of ERK1/2, but not that of P38, JNK. This was accompanied by a reduced interaction between ERK1/2 and IQGAP1. Conclusion: IQGAP1 contributes to AngII-induced apoptosis of podocytes by interacting with the ERK1/2 signaling protein.