初级纤毛细胞外氧感受器功能和机制研究

目的: 探索初级纤毛是否为PC12细胞的细胞外氧感受器。方法: 通过小干扰RNA（siRNA）干扰细胞纤毛内转运蛋白88的表达抑制体外培养PC12细胞初级纤毛的发生；免疫荧光染色法观察缺氧诱导因子1α（HIF-1α）、核因子E2相关因子2（Nrf2）核转位和PC12细胞初级纤毛生长情况；实时定量RT-PCR法检测HIF-1α、Nrf2、血管内皮生长因子（VEGF）和超氧化物歧化酶（SOD）基因表达。结果: siRNA干扰组细胞的初级纤毛被抑制。与常氧对照组比较，缺氧对照组和阴性对照组细胞的HIF-1α和Nrf2发生了明显的核转位，细胞内HIF-1α、Nrf2、VEGF基因表达量增加，SOD表达量下降；siRNA干扰组细胞在缺氧状态下HIF-1α和Nrf2未发生核转位，细胞内HIF-1α、Nrf2、VEGF基因表达受到抑制，而SOD表达量升高。结论: PC12细胞的初级纤毛可能具有细胞外氧感受器的作用，可以感知细胞外环境中的缺氧和氧化应激状态，并通过一定途径将缺氧信号传导至细胞内，进而启动细胞抗缺氧机制。
Abstract: Objective: To investigate the function of primary cilium as an oxygen sensor in PC12 cells. Methods: The PC12 cells were transfected with IFT88 siRNA. The nuclear translocation of hypoxia inducible factor-1α (HIF-1α), nuclear factor erythroid-2 related factor 2 (Nrf2), and ciliogenesis were observed by immunofluorescence staining; and the mRNA expressions of HIF-1α, Nrf2, vascular endothelial growth factor (VEGF) and superoxide dismutase (SOD) were detected by real-time RT-PCR. Results: The ciliogenesis was inhibited in PC12 cells transfected with IFT88 siRNA. In hypoxia group and scramble control group, nuclear translocations of HIF-1α and Nrf2 were observed and mRNA expressions of HIF-1α, Nrf2, VEGF were increased, and those of SOD were decreased. While in PC12 cells transfected with IFT88 siRNA, nuclear translocations of HIF-1α and Nrf2 were not observed, and mRNA expressions of HIF-1α, Nrf2, VEGF were inhibited, and mRNA expression of SOD was increased. Conclusion: Primary cilia may act as an oxygen sensor to transfer the information related to hypoxia and oxidative stress into cells, activating intracellular defense mechanism against the hypoxic injuries. Key words: PC12 cells Cilia Receptors, sensory Anoxia/physiopathology Mechanotransduction, cellular RNA, small interfering