Inactivation of glycogen synthase kinase-3β and up-regulation of LINGO-1 are involved in LINGO-1 antagonist regulated survival of cerebellar granular neurons
Inactivation of glycogen synthase kinase-3β and up-regulation of LINGO-1 are involved in LINGO-1 antagonist regulated survival of cerebellar granular neurons
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DOI：
10.1007/s10571-007-9258-6
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发表时间：
2008-08-01
影响因子：
4
通讯作者：
Ju, Gong
中科院分区：
文献类型：
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作者：
Zhao, Xiang-Hui;Jin, Wei-Lin;Ju, Gong
LINGO-1在中枢神经系统轴突再生和少突胶质细胞成熟的中枢调控中有重要作用。我们最近证明了LINGO-1拮抗剂（LINGO-1- fc）预处理可以抑制低钾诱导的小脑颗粒神经元（CGNs）凋亡。在本研究中，我们通过Western blot和原位GST下拉实验检测了LINGO-1-Fc的神经保护机制。CGN培养物在含有LINGO-1-Fc或对照蛋白（浓度为10 μ g/ml）的培养基中预孵育2 h，然后切换到有相应蛋白存在的低钾培养基中。在指定的时间间隔收获培养物进行连续分析。与对照组相比，LINGO-1-Fc预处理抑制了GSK-3 β的激活/去磷酸化，并激活了几个凋亡相关的信号因子GSK-3 β、ERK1/2和Rho GTPases。此外，低钾刺激能提高CGN培养物内源性LINGO-1的表达水平，而LINGO-1拮抗剂处理能抑制其表达水平。虽然p75（NTR）和Nogo-A蛋白水平在凋亡过程中以不同的模式下调，但LINGO-1-Fc的应用对它们都没有影响。综上所述，这些结果提示LINGO-1拮抗剂调节神经元存活的新机制涉及LINGO-1蛋白合成和GSK-3通路失活。
LINGO-1 has been critically implicated in the central regulation of CNS axon regeneration and oligodendrocyte maturation. We have recently demonstrated that pretreatment with LINGO-1 antagonist (LINGO-1-Fc) inhibited low potassium-induced cerebellar granular neurons (CGNs) apoptosis. In the present study, we examined the neuroprotective mechanism of LINGO-1-Fc by Western blot and in situ GST pull-down assay. CGN cultures were preincubated in medium with LINGO-1-Fc or control protein at the concentration of 10 mu g/ml for 2 h and then switched to low potassium medium in the presence of corresponding proteins. Cultures were harvested at indicated time intervals for successive analysis. Several apoptosis-associated signaling factors, GSK-3 beta, ERK1/2, and Rho GTPases, were observed to be activated in response to potassium deprivation and the activation/dephosphorylation of GSK-3 beta was suppressed by LINGO-1-Fc pretreatment compared with control group. Besides, the endogenous LINGO-1 expression level of CGN cultures was augmented by low potassium stimuli and restrained by LINGO-1 antagonist treatment. Although the protein level of p75(NTR) and Nogo-A were down-regulated in different patterns during apoptosis, neither of them was affected by LINGO-1-Fc application. Taken together, these results suggest a new mechanism of LINGO-1 antagonist regulated neuronal survival involving protein synthesis of LINGO-1 and inactivation of GSK-3 pathway.