Zeng Zhiwen, Wang Haitao, Shang Fu, Zhou Lihua, Little Peter J, Quirion Remi, Zheng Wenhua
Faculty of Health Science, University of Macau, Room 4021, Building E12, Avenida de Universidade Taipa, Macau, People's Republic of China.
Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Collaborative Innovation Center for Neurogenetics and Channelopathies, Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, People's Republic of China.
Psychopharmacology (Berl). 2016 Mar;233(5):785-94. doi: 10.1007/s00213-015-4168-7. Epub 2015 Dec 2.
Lithium is currently used in the treatment of mental illness. We have previously reported that lithium stimulated the protein kinase B/Forkhead box O1 (Akt/FoxO1) pathway in rats. However, little information is available regarding its neuroprotective role of this pathway and underlying mechanisms.
PC12 cells treated with serum deprivation were used as a toxicity model to study the protective effect of lithium and its underlying mechanisms.
Cell viability was determined by methyl thiazolyl tetrazolium assay and Hoechst staining. FoxO1 subcellular location and its overexpression were used to study the underlying mechanisms. Various pathway inhibitors were used to investigate the possible pathways, while the phosphorylation of Akt and FoxO1 was analyzed by Western blot.
Lithium pretreatment dose-dependently reduced PC12 cell apoptosis induced by serum starvation. The protective effect of lithium was abolished by LY294002, a PI3K-specific inhibitor, and Akt inhibitor Akt inhibitor VIII, whereas mitogen-activated protein kinase kinase (MEK kinase) inhibitor U0126 had no effect. Lithium induced the phosphorylation of Akt and FoxO1 in a time- and concentration-dependent manner. Lithium-induced phosphorylation of Akt and FoxO1 is mediated by the PI3K/Akt pathway. Serum deprivation caused nuclear translocation of FoxO1 while application of lithium reversed the effect of serum deprivation. Moreover, overexpression of FoxO1 enhanced cell apoptosis induced by serum withdrawal. Finally, lithium was found to reduce the exogenous and endogenous FoxO1 protein levels in PC12 cells in a concentration-dependent fashion.
The protective effect of lithium against serum starvation cell death is mediated by the PI3K/Akt/FoxO1 pathway.
锂目前用于治疗精神疾病。我们之前报道过锂能刺激大鼠体内的蛋白激酶B/叉头框蛋白O1（Akt/FoxO1）信号通路。然而，关于该通路的神经保护作用及其潜在机制的信息却很少。
将血清剥夺处理的PC12细胞用作毒性模型，以研究锂的保护作用及其潜在机制。
通过噻唑蓝比色法和Hoechst染色测定细胞活力。利用FoxO1亚细胞定位及其过表达来研究潜在机制。使用各种信号通路抑制剂来探究可能的信号通路，同时通过蛋白质免疫印迹法分析Akt和FoxO1的磷酸化情况。
锂预处理能剂量依赖性地减少血清饥饿诱导的PC12细胞凋亡。PI3K特异性抑制剂LY294002和Akt抑制剂Akt inhibitor VIII可消除锂的保护作用，而丝裂原活化蛋白激酶激酶（MEK激酶）抑制剂U0126则无此作用。锂能以时间和浓度依赖性方式诱导Akt和FoxO1的磷酸化。锂诱导的Akt和FoxO1磷酸化是由PI3K/Akt信号通路介导的。血清剥夺导致FoxO1核转位，而锂的应用可逆转血清剥夺的作用。此外，FoxO1的过表达增强了血清撤除诱导的细胞凋亡。最后，发现锂能以浓度依赖性方式降低PC12细胞中外源性和内源性FoxO1蛋白水平。
锂对血清饥饿诱导的细胞死亡的保护作用是由PI3K/Akt/FoxO1信号通路介导的。
