Activation of phosphoinositide‐3 kinase/Akt pathway by FeSO4 in rat cerebral cortex synaptic endings
Activation of phosphoinositide‐3 kinase/Akt pathway by FeSO4 in rat cerebral cortex synaptic endings
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DOI：
10.1002/jnr.21406
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发表时间：
2007-10
影响因子：
4.2
通讯作者：
R. Uranga;M. V. Mateos;N. Giusto;G. Salvador
中科院分区：
文献类型：
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作者：
R. Uranga;M. V. Mateos;N. Giusto;G. Salvador
本工作的目的是研究在氧化应激条件下，磷脂酰肌醇-3-激酶(PI3K)/Akt通路在突触终末中的作用。从大鼠大脑皮层提纯的突触体经50μM的FeSO4染毒不同时间。与对照条件相比，在FeSO4存在下孵育5min后，3‐(4，5‐Dimethylthiazol‐2‐yl)‐2，5‐diphenyltetrazolium溴化物还原和乳酸脱氢漏出受到显著影响。在[γ-32P]-ATP孵育的整个突触体中，Fe2+作用5min后，磷脂酰肌醇(PPI)的标记增加。这种作用可被特异性的PI3K抑制剂LY294002所阻止。用Fe2+预先孵育5min的突触体内获得的抗P85免疫沉淀物(IP)，其PI3K活性比对照条件下恢复的活性高两倍。此外，Akt的激活与PI3K的激活在时间上是一致的。LY294002不能阻止Fe2+引起的乳酸脱氢酶漏出和四甲基偶氮唑蓝还原的减少。我们的结果表明，游离铁刺激PI3K/Akt通路的早期激活，但这种激活不足以保护突触末端免受氧化损伤。©2007 Wiley-Liss Inc.
The aim of this work was to study the involvement of the phosphoinositide‐3‐kinase (PI3K)/Akt pathway in synaptic endings incubated under oxidative stress conditions. Synaptosomes purified from rat cerebral cortex were exposed to FeSO4 (50 μM) for different periods of time. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) reduction and lactate dehydrogenate (LDH) leakage were significantly affected after 5 min of incubation in the presence of FeSO4, with respect to control conditions. In whole synaptosomes incubated in the presence of [γ‐32P]ATP, phosphoinositide (PPI) labeling was increased after 5 min of Fe2+ exposure. This effect was prevented by the specific PI3K inhibitor LY294002. Anti‐p85 immunoprecipitates (IPs) obtained from synaptosomes preincubated with Fe2+ (5 min) showed a PI3K activity two‐fold higher than the activity recovered under control conditions. Additionally, Akt activation was temporally coincident with PI3K activation. LY294002 was not able to prevent the LDH leakage and diminution of MTT reduction induced by Fe2+. Our results demonstrate that free iron provokes the early activation of PI3K/Akt pathway, but this activation is not sufficient for protecting synaptic endings from oxidative damage. © 2007 Wiley‐Liss, Inc.