Lv Xiaoguang, Fan Zheyu, Cao Fangqi, Liu Wenbin, Huang Zhiwei, Shi Ping
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Shanghai Key Laboratory of Crime Scene Evidence, Shanghai Research Institute of Criminal Science and Technology, Zhongshan North No 1 Road, Shanghai, 200083, China.
Chem Biol Interact. 2023 Jan 5;369:110268. doi: 10.1016/j.cbi.2022.110268. Epub 2022 Nov 15.
Clioquinol (CQ) is considered as a promising drug of neurodegenerative diseases. However, the underlying mechanism is unclear. Our previous study has proved that CQ induces S-phase cell cycle arrest through the elevation of intracellular calcium concentration ([Ca2+]i) with high levels of SERCA2. Furthermore, it could induce autophagy in an intracellular calcium independent manner in human neurotypic SH-SY5Y cells. In this study, the involvement of calreticulin (CRT) in autophagy induced by CQ was investigated. Our results illustrated the endoplasmic reticulum (ER) stress induced by CQ and DTT led to the cell death in different manners. DTT, an ER stress positive control, induced UPR accompanied with up-regulation of CRT and apoptosis, while CQ inhibited UPR accompanied with down-regulation of CRT，resulting in autophagy. Then, overexpression of CRT was shown to cause UPR and decrease [Ca2+]i, leading to cell apoptosis and inhibition of S-phase arrest induced by CQ. While the UPR was alleviated and autophagy was further enhanced in CRT deficient cells by using targeted siRNA. Meanwhile, down-regulation of CRT resulted in [Ca2+]i overload and induction of S-phase arrest. Finally, we found that the effect of CQ on the HT22 cells was similar to that on the SH-SY5Y cells. Our data showed for the first time that CQ decreased expression of CRT, leading to autophagy, an increase of [Ca2+]i, and cell S-phase arrest in the neurotypic cells. The present study describes the cellular signal pathways regulating autophagy by CQ and highlights the potential therapeutic application of CQ in neurodegenerative disorders.
氯碘羟喹（CQ）被认为是一种有前景的神经退行性疾病治疗药物。然而，其潜在机制尚不清楚。我们之前的研究证明，CQ通过升高细胞内钙浓度（[Ca2+]i）并伴有高水平的肌浆网钙ATP酶2（SERCA2）诱导S期细胞周期停滞。此外，它可以在人神经型SH-SY5Y细胞中以细胞内钙非依赖的方式诱导自噬。在本研究中，我们调查了钙网蛋白（CRT）在CQ诱导的自噬中的作用。我们的结果表明，CQ和二硫苏糖醇（DTT）诱导的内质网（ER）应激以不同方式导致细胞死亡。DTT作为ER应激阳性对照，诱导未折叠蛋白反应（UPR）并伴有CRT上调和细胞凋亡，而CQ抑制UPR并伴有CRT下调，从而导致自噬。然后，CRT的过表达导致UPR并降低[Ca2+]i，导致细胞凋亡并抑制CQ诱导的S期停滞。而通过使用靶向小干扰RNA（siRNA），在CRT缺陷细胞中UPR得到缓解且自噬进一步增强。同时，CRT的下调导致[Ca2+]i过载并诱导S期停滞。最后，我们发现CQ对HT22细胞的作用与对SH-SY5Y细胞的作用相似。我们的数据首次表明，CQ降低CRT的表达，导致神经型细胞发生自噬、[Ca2+]i增加和细胞S期停滞。本研究描述了CQ调节自噬的细胞信号通路，并突出了CQ在神经退行性疾病中的潜在治疗应用。
