受体相互作用蛋白1(RIP1)对BCG诱导小鼠巨噬细胞凋亡的调控作用

Regulation of Receptor-interacting Protein 1 on Apoptosis of Macrophage Induced by Bacillus Calmette-Guerin

旨在通过构建受体相互作用蛋白1(RIP1)腺病毒干扰载体,研究其对BCG诱导的RAW264.7细胞凋亡相关指标的影响,以探讨其在BCG诱导RAW264.7凋亡过程中的调控作用。笔者构建RIP1腺病毒干扰载体,并转染感染BCG的小鼠RAW264.7细胞系,利用流式细胞仪检测各处理细胞凋亡率、细胞线粒体膜电位、细胞活性氧水平及细胞周期等指标,并用Western blot检测凋亡相关蛋白的表达水平。结果显示:BCG感染显著上调了RIP1的蛋白表达水平并提高了小鼠巨噬细胞RAW264.7的凋亡率,当RIP1被干扰后,BCG感染后的RAW264.7细胞凋亡率和活性氧水平显著降低,而促凋亡蛋白Bax表达量显著下调,线粒体膜电位和抑凋亡蛋白表达量上调。同时,BCG感染后细胞周期滞留于G_1期。BCG感染可有效上调RIP1表达量并诱导RAW264.7细胞凋亡。RIP1通过下调BCG感染后RAW264.7细胞的线粒体膜电位,上调活性氧含量并提高凋亡相关蛋白Bax/Bcl-2比值,使细胞周期阻滞于G_1期从而参与诱导细胞凋亡。

The purpose of this study was to explore the effect of RIP1 on apoptosis of RAW264.7 cell by assessment the apoptosis related indicators of RAW264.7 cell treated with RIP1 RNAi vector or/and BCG infection. The RIP1 adenovirus RNAi vector was constructed and transfected into BCG-infected RAW264.7 cell line. Flow cytometry was used to detect the apoptotic rate, mitochondrial membrane potential, cell reactive oxygen species and cell cycle of RAW264.7 cell. The expression of RIP1 and apoptosis associated proteins were examined by Western blot. The results showed that BCG-infection can significantly induce RAW264.7 cells apoptosis, which was accompanied with up-regulation of PIP1 protein. In addition, a RIP1 adenovirus RNAi vector showed an ability to reduce the BCG-induced macrophage apoptosis along with an increased mitochondrial membrane potential and reduced reactive oxygen species (ROS). It also down-regulated Bax expression and up-regulated Bcl-2 expression of RAW264.7 cell infected with BCG. Intriguingly, cell cycle of RAW264.7 cell was arrested in G 1 phase. In conclusion, RIP1 involves in BCG-induced apoptosis by down-regulating mitochondrial membrane potential, increasing the production of ROS and the ratio of apoptosis-related proteins (Bax/Bcl-2) and arresting the cell cycle in G 1 phase in BCG-infectied RAW264.7.