IGF-1 Alleviates NMDA-Induced Excitotoxicity in Cultured Hippocampal Neurons Against Autophagy via the NR2B/PI3K-AKT-mTOR Pathway
IGF-1 Alleviates NMDA-Induced Excitotoxicity in Cultured Hippocampal Neurons Against Autophagy via the NR2B/PI3K-AKT-mTOR Pathway
复制标题
IGF-1 通过 NR2B/PI3K-AKT-mTOR 途径减轻培养海马神经元中 NMDA 诱导的兴奋性毒性，以抵抗自噬。
DOI：
10.1002/jcp.24607
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发表时间：
2014-11-01
影响因子：
5.6
通讯作者：
Yin, Yanling
中科院分区：
文献类型：
--
作者：
Wang, Yansong;Wang, Wei;Yin, Yanling
胰岛素样生长因子-1（IGF-1）是一种脑特异性多功能蛋白，参与神经元极性和轴突导向。成熟的IGF-1触发三种酶，丝裂原活化蛋白激酶（MAPK）、磷脂酰肌醇3-激酶（PI 3 K）和磷酸肌醇磷脂酶C-γ（PLC-γ），它们是其主要的下游调节剂。PI 3 K-AKT信号通路位于哺乳动物雷帕霉素靶蛋白（mTOR）的上游，在自噬的诱导中起着重要作用。然而，IGF-1对兴奋性毒性的神经保护作用是否是通过PI 3 K/AKT/mTOR通路的自噬介导的仍有待阐明。通过微管相关蛋白轻链3（LC 3）转化确定NMDA处理后自噬的诱导，并通过监测培养的海马神经元中caspase 3的切割来评估这种自噬的结果。采用MTT法和LDH法检测细胞活力，PI染色检测细胞自噬命运和IGF-1的保护作用。此外，IGF-1被发现减少自噬诱导的NMDA使用透射电子显微镜和MDC染色。IGF-1对自噬的保护作用伴随着磷酸化AKT（p-AKT）和磷酸化mTOR（p-mTOR）的上调，该作用可被PI 3 K抑制剂阻断。同时，IGF-1可阻断NR 2B的激活导致p-AKT和p-mTOR的下调。总之，这些数据表明，NMDA诱导培养的海马神经元中的自噬，随后是凋亡，并且IGF-1可以通过抑制NR 2B受体和激活PI 3 K-AKT-mTOR通路来阻断这种作用。(C)2014年威利期刊公司
Insulin-like growth factor-1 (IGF-1) is a brain-specific multifunctional protein involved in neuronal polarity and axonal guidance. Mature IGF-1 triggers three enzymes, mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and phosphoinositide phospholipase C-gamma (PLC-gamma), which are its predominant downstream regulators. The PI3K-AKT signaling pathway is upstream of the mammalian target of rapamycin(mTOR), which is of great importance in the induction of autophagy. However, whether the neuroprotective effect of IGF-1 against excitotoxicity is mediated by autophagy through the PI3K/AKT/mTOR pathway remains to be elucidated. The induction of autophagy following NMDA treatment was determined by microtubule-associated protein light chain 3 (LC3) conversion and the result of this autophagy was assessed by monitoring the cleavage of caspase 3 in cultured hippocampal neurons. Cell viability was determined using MTT and LDH assay, and PI-staining was used to estimate the fate of autophagy and the protective effect of IGF-1. In addition, IGF-1 was found to decrease autophagy induced by NMDA using transmission electron microscopy and MDC staining. The protective effect of IGF-1 against autophagy was accompanied with up-regulation of phospho-AKT (p-AKT) and phospho-mTOR (p-mTOR), which was blocked by the inhibitor of PI3K. At the same time, the activation of NR2B resulting in the down-regulation of p-AKT and p-mTOR was blocked by IGF-1. Together, these data suggest that NMDA induces the autophagy, followed by apoptosis in cultured hippocampal neurons, and that IGF-1 can block this effect via inhibition of NR2B receptors and activation of the PI3K-AKT-mTOR pathway. (C) 2014 Wiley Periodicals, Inc.