Inactivation of glycogen synthase kinase-3beta and up-regulation of LINGO-1 are involved in LINGO-1 antagonist regulated survival of cerebellar granular neurons.
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 mug/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-3beta, ERK1/2, and Rho GTPases, were observed to be activated in response to potassium deprivation and the activation/dephosphorylation of GSK-3beta 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.
Zhao
Xiang-Hui
XH
Institute of Neurosciences, Shanghai JiaoTong University, 800 Dongchuan Road, Shanghai, P.R. China.
Jin
Wei-Lin
WL
Wu
Jiang
J
Mi
Sha
S
Ju
Gong
G
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D007074:Immunoglobulin G / Q000235:genetics; D008565:Membrane Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000187:drug effects / Q000378:metabolism; D009185:Myelin Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D000070798:Nogo Proteins; D010766:Phosphorylation / Q000187:drug effects; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020800:Receptor, Nerve Growth Factor / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*; D020741:rho GTP-Binding Proteins / Q000187:drug effects / Q000378:metabolism
D007074:Immunoglobulin G; C525164:LINGO1 protein, rat; D008565:Membrane Proteins; D009185:Myelin Proteins; D009419:Nerve Tissue Proteins; D000070798:Nogo Proteins; D020800:Receptor, Nerve Growth Factor; D011993:Recombinant Fusion Proteins; C000603197:Rtn4 protein, rat; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D048052:Mitogen-Activated Protein Kinase 3; D038362:Glycogen Synthase Kinase 3; D020741:rho GTP-Binding Proteins; D011188:Potassium