mTOR pathway inhibition prevents neuroinflammation and neuronal death in a mouse model of cerebral palsy
mTOR pathway inhibition prevents neuroinflammation and neuronal death in a mouse model of cerebral palsy
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DOI：
10.1016/j.nbd.2015.10.001
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发表时间：
2016-01-01
影响因子：
6.1
通讯作者：
Crino, Peter B.
中科院分区：
文献类型：
--
作者：
Srivastava, Isha N.;Shperdheja, Jona;Crino, Peter B.
背景和目的：哺乳动物雷帕霉素靶蛋白（mTOR）通路信号传导控制细胞对缺氧和炎症的反应，包括诱导自噬和细胞存活。脑性瘫痪（CP）是一种与缺氧和炎性脑损伤相关的神经发育障碍，然而，尚未研究mTOR调节在CP中的作用。我们假设，mTOR通路抑制将减少炎症和预防神经元死亡的小鼠模型CP。方法：小鼠幼崽（P6）进行缺氧缺血和脂多糖诱导的炎症（HIL），CP模型引起海马，脑室周围白色物质，和新皮质内的神经元损伤。HIL后立即使用雷帕霉素（一种mTOR抑制剂; 5 mg/kg）或PF-4708671（一种下游p70 S6激酶抑制剂，S6 K，75 mg/kg）实现mTOR途径抑制，然后持续3天。检测mTOR效应子p70 S6激酶和核糖体S6蛋白的磷酸化激活以及缺氧诱导因子1（HIF-1 α）的表达。使用Fluoro-Jade C（FJC）定义神经元细胞死亡，并使用Beclin-1和LC 3 II表达测量自噬。结果：HIL后24和48 h，神经元死亡、HIF-1 α表达增强和大量Iba-1标记的活化小胶质细胞明显。基础mTOR信号传导，如磷酸化-S6和-S6 K水平所证明，HIL未改变。雷帕霉素或PF-4，708，671治疗显著降低mTOR信号传导、神经元死亡、HIF-1 α表达和小胶质细胞活化，与Beclin-1和LC 3 II（自噬诱导的标志物）表达增强一致。HIL后持续的mTOR信号提示自噬诱导失败，这可能导致CP中的神经元死亡。这些结果表明，mTOR信号转导可能是一种新的治疗靶点，以减少CP中的神经元细胞死亡。(C)2015 Elsevier Inc. All rights reserved.
Background and purpose: Mammalian target of rapamycin (mTOR) pathway signaling governs cellular responses to hypoxia and inflammation including induction of autophagy and cell survival. Cerebral palsy (CP) is a neurodevelopmental disorder linked to hypoxic and inflammatory brain injury however, a role for mTOR modulation in CP has not been investigated. We hypothesized that mTOR pathway inhibition would diminish inflammation and prevent neuronal death in a mouse model of CP.Methods: Mouse pups (P6) were subjected to hypoxia-ischemia and lipopolysaccharide-induced inflammation (HIL), a model of CP causing neuronal injury within the hippocampus, periventricular white matter, and neocortex. mTOR pathway inhibition was achieved with rapamycin (an mTOR inhibitor; 5 mg/kg) or PF-4708671 (an inhibitor of the downstream p70S6kinase, S6K, 75 mg/kg) immediately following HIL, and then for 3 subsequent days. Phospho-activation of the mTOR effectors p70S6kinase and ribosomal S6 protein and expression of hypoxia inducible factor 1 (HIF-1 alpha) were assayed. Neuronal cell death was defined with Fluoro-Jade C (FJC) and autophagy was measured using Beclin-1 and LC3II expression. Iba-1 labeled, activated microglia were quantified.Results: Neuronal death, enhanced HIF-1 alpha expression, and numerous Iba-1 labeled, activated microglia were evident at 24 and 48 h following HIL Basal mTOR signaling, as evidenced by phosphorylated-S6 and -S6K levels, was unchanged by HIL. Rapamycin or PF-4,708,671 treatment significantly reduced mTOR signaling, neuronal death, HIF-1 alpha expression, and microglial activation, coincident with enhanced expression of Beclin-1 and LC3II, markers of autophagy induction.Conclusions: mTOR pathway inhibition prevented neuronal death and diminished neuroinflammation in this model of CP. Persistent mTOR signaling following HIL suggests a failure of autophagy induction, which may contribute to neuronal death in CP. These results suggest that mTOR signaling may be a novel therapeutic target to reduce neuronal cell death in CP. (C) 2015 Elsevier Inc. All rights reserved.