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肾脏病与透析肾移植杂志

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蛋白磷酸酶PHLPP2通过线粒体凋亡途径加重顺铂诱导的小鼠急性肾损伤

  

  • 出版日期:2020-10-28 发布日期:2020-10-30

Protein phosphatase PHLPP 2 promotes cisplatin induced acute kidney injury in mice through mitochondrial apoptosi

  • Online:2020-10-28 Published:2020-10-30

摘要: 目的:研究Pleckstrin同原序列富亮氨酸重复片段蛋白磷酸酶(PHLPP2)在急性肾损伤(AKI)发生发展中的作用及机制;方法:将20只野生型C57BL/6(WT)小鼠与20只敲除PHLPP2(PHLPP2-/-)表达的转基因小鼠按是否使用顺铂(CDDP)处理进行分组,即WT对照组、WT CDDP处理组、PHLPP2-/-对照组和PHLPP2-/- CDDP处理组(每组10只)。3d后处死小鼠,RTPCR及Western Blot检测各组小鼠中PHLPP2 mRNA及蛋白水平;免疫组织化学染色检测肾组织PHLPP2表达及定位;HE与TUNEL染色检测肾组织损害和细胞的凋亡情况;分离并鉴定小鼠肾小管上皮细胞(RTECs),透射电子显微镜观察RTECs中线粒体结构;JC1法检测RTECs中线粒体膜电位变化;Western Blot检测RTECs中促凋亡蛋白Bax、Caspase3,及凋亡抑制蛋白Bcl2和Akt的Thr308与Ser473位点磷酸化水平。结果:CDDP成功诱导AKI模型,肾脏组织中PHLPP2表达显著增加;与WT CDDP组相比,PHLPP2-/-CDDP组小鼠的血尿素氮、血清肌酐明显降低,肾组织结构损害较轻,凋亡细胞减少,线粒体结构损伤减轻,线粒体膜电位下降减少;敲除PHLPP2基因表达可显著促进Bcl2蛋白表达,而抑制Bax、Caspase3蛋白表达,且PHLPP2基因通过对Akt的Thr308与Ser473位点去磷酸化而调节上述蛋白表达。结论:敲除PHLPP2表达能够通过减轻线粒体膜电位的下降,保护线粒体的正常结构及功能,从而通过线粒体途径的凋亡改善AKI损伤。

关键词: Pleckstrin同原序列富亮氨酸重复片段蛋白磷酸酶2, 急性肾损伤, 线粒体, 凋亡

Abstract: Objective:To study the role and mechanism of protein phosphatase PHLPP2 in  development of acute kidney injury (AKI); Methodology:Wild type C57BL/6 (WT) and knockout PHLPP2(PHLPP2-/-) mice were divided into WT control group,WT cisplatin (CDDP) treatment group,PHLPP2-/- control group and PHLPP2-/- CDDP treatment group (10 mice in each group) to establish AKI model.Three days later,the mice were killed.The mRNA and protein levels of PHLPP2 were detected by RTPCR and Western Blot; HE and TUNEL staining were used to detect renal tissue damage and cell apoptosis,renal tubular epithelial cells (RTECS) were isolated and identified; JC1 method was used to detect the changes of mitochondrial membrane potential; The protein levels of Bax,Caspase3,and Bcl2 and the phosphorylation levels of Thr308 and Ser473 in AKt Kinase were detected by Western Blot assay.Results:In AKI model induced by CDDP,expression of PHLPP2 in kidney tissue was significantly increased; compared with WT CDDP group,renal tissue structure damage and apoptosis were alleviated.Mitochondrial structure damage was reduced,and mitochondrial membrane potential was decreased; Knockout of PHLPP2 gene could significantly promote expression of Bcl2 protein,but inhibit expression of Bax and caspase3.PHLPP2 gene regulated expression of these proteins through dephosphorylation of thr308 and ser473 of Akt.Conclusion:Knockout of PHLPP2 can protect normal structure and function of mitochondria by alleviating the decline of mitochondrial membrane potential,thus improving AKI injury through mitochondrial apoptosis.