线粒体核糖体蛋白S22对细胞凋亡的影响

Effects of mitochondrial ribosomal protein S22 on apoptosis

目的探讨RNA干扰线粒体核糖体蛋白S22(MRPS22)表达对线粒体损伤和细胞凋亡的影响。方法将靶向MRPS22的特异性shRNA片段转入体外培养的L02细胞,48 h后采用Western blotting方法确认shRNA的干扰效果;电镜及JC-1染色法观察线粒体结构损伤和膜电位的变化;Annexin V/PI染色法观察RNA干扰MRPS22基因表达对细胞凋亡的影响。结果 shMRPS22转入细胞后能够有效抑制L02细胞MRPS22基因的表达;电镜观察显示,RNA干扰组L02细胞线粒体肿胀,呈空泡样变,嵴减少或消失;JC-1染色显示,RNA干扰组L02细胞较对照组绿色荧光颗粒明显增加,提示线粒体膜电位下降;Annexin V/PI染色法观察细胞凋亡结果表明,抑制MRPS22基因表达可以诱导正常细胞凋亡。结论 MRPS22是影响线粒体功能的关键蛋白质,该蛋白在细胞凋亡的发生过程中也起到了非常重要的作用,提示MRPS22可作为mtDNA异常相关疾病临床诊断和治疗的新靶点。

[Objective] To evaluate the effects of RNA interference of Mitochondrial Ribosomal Protein S22 （MRPS22） on mitochondrial injury and apoptosis. [Methods] Cultured L02 ceils were infected with MRPS22 targeting shRNA, and the gene silencing effects were verified with Western blotting after 48 h. The mitochondrial injury and the membrane potential change were assessed using election microscope and JC-1 staining. Cell apoptosis was evaluated using flow cytometry after Annexin V/PI staining. [Results] This study showed that shMRPS22 effectively interfered the expression of MRPS22 gene. Electron microscopy of the MRPS22 gene silenced L02 cells revealed the swelling of mitochondria and vacuolar degeneration. It was also found that the crista of mitochondria reduced even disappeared. JC-1 staining showed the increased green fluorescence particle in the RNA interference L02 cells, which suggested the decline of mitochondrial membrane potential. More cell apoptosis was observed in the RNA interference L02 cells by flow cytometry after Annexin V/PI staining, suggesting that silence of MRPS22 gene may induce ceil apoptosis. [Conclusion] MRPS22 is one of the key proteins that maintain the mitochondrial functions, and it might play a very important role in cell apoptosis. MRPS22 could be a new target for the diagnosis and treatment of mt DNA defect associated diseases.