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目的探讨致病性大肠杆菌(Enteropathogenic Escherichia coli,EPEC)外膜蛋白Intimin及其受体Tir在EPEC致HeLa细胞线粒体功能障碍中的作用。方法将EPEC外膜蛋白Intimin及其受体Tir删除株、相应质粒互补株或染色体互补株感染HeLa细胞,用线粒体膜电位(Mitochondria membrane potential,MMP)检测试剂JC-1染色细胞线粒体,通过多功能酶标仪检测MMP水平,Western blot检测Intimin的表达及Tir的转位。结果与野生型菌株相比,Eae删除株和Tir删除株感染细胞的MMP功能显著减弱(P<0.05),Eae删除株功能能被质粒表达相应蛋白所互补,Tir删除株不能被质粒表达Tir互补,但可被染色质表达野生型Tir或TirY474S互补,而染色质TirS434A突变株不能引起明显的MMP下降。结论 Intimin和Tir是参与线粒体功能障碍的重要分子;TirS434在线粒体功能障碍中起重要作用。
Objective To investigate the role of intimin and its receptor Tir on the mitochondrial dysfunction of HeLa cells induced by EPEC in Enteropathogenic Escherichia coli (EPEC). Methods HeLa cells were infected with Intimin and its receptor Tir deletion strain, corresponding plasmid complement or chromosome complement of EPEC. Mitochondria of JC-1 staining cells were detected by Mitochondria membrane potential (MMP) MMP was detected by microplate reader, the expression of Intimin and the translocation of Tir were detected by Western blot. Results Compared with the wild-type strain, the Eae deletion and Tir deletion significantly decreased the MMP (P <0.05). The function of Eae deletion was complemented by the corresponding protein expression plasmid. Tir deletion could not be expressed by Tir , But could be complemented by chromatin expression in wild-type Tir or TirY474S, whereas chromatin TirS434A mutant did not cause significant MMP decline. Conclusion Intimin and Tir are involved in mitochondrial dysfunction; TirS434 plays an important role in mitochondrial dysfunction.