title: Neuroprotection of interleukin-6 against NMDA-induced neurotoxicity is mediated by JAK/STAT3, MAPK/ERK, and PI3K/AKT signaling pathways.
abstract: We have previously shown that interleukin-6 (IL-6) has neuroprotective effect against N-methyl-D-aspartate (NMDA)-induced excitotoxicity. The current study aimed to reveal signal transduction pathways involved in the IL-6 neuroprotection. Cerebellar granule neurons (CGNs) from postnatal 8-day infant rats were exposed to IL-6 (120 ng/ml) for 8 days and stimulated with NMDA (100 μM) for 15 or 30 min. Dynamic intracellular Ca(2+) fluorescence intensity, cytosolic Ca(2+)-dependent phospholipase A2 (cPLA2) expression, and apoptosis and necrosis in cultured CGNs were measured by laser scanning confocal microscope, real-time PCR and Western blot, and annexin V-FITC/propidium iodide staining, respectively. NMDA stimulation of neurons evoked an intracellular Ca(2+) overload, an upregulated expression of cPLA2, and an increase in cell death. Chronic IL-6 exposure prevented the NMDA-evoked neuronal Ca(2+) overload, cPLA2 expression upregulation, and apoptosis and necrosis. Anti-gp130 monoclonal antibody (mAb), a blocker of gp130 that is a 130-kDa signal-transducing β-subunit of IL-6 receptor complex, blocked these effects of IL-6 preventing NMDA neurotoxicity. AG490, PD98059, or LY294002, inhibitors specific for the intracellular signals, JAK, MAPK, and PI3K, respectively, partially blocked these IL-6 neuroprotective effects. Phosphorylation levels of STAT3, ERK1/2, and AKT, the downstream proteins for these enzymes of JAK, MAPK, and PI3K, respectively, were elevated by IL-6 pretreatment. The enhanced activation of STAT3, ERK1/2, and AKT by IL-6 was abolished by AG490, PD98059, and LY294002, respectively. Anti-gp130 mAb attenuated the activation of all the three detected signaling molecules. The present findings suggest that IL-6 neuroprotection is jointly mediated by the cellular signal transduction pathways, gp130-JAK-STAT3, gp130-MAPK-ERK, and gp130-PI3K-AKT.
authors.affiliation: Department of Physiology, School of Medicine, Nantong University, Nantong, China.
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Fang
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Jiang
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Han
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Peng
authors.forename: Yi-Hua
authors.initials: YH
authors.lastname: Qiu
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D050822:Cytokine Receptor gp130 / Q000276:immunology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology*; D053612:Janus Kinases / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology; D016202:N-Methylaspartate / Q000633:toxicity*; D009474:Neurons / Q000187:drug effects / Q000201:enzymology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins / Q000633:toxicity*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D054510:Phospholipases A2, Cytosolic / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D020032:Tyrphostins / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000911:Antibodies, Monoclonal; D002867:Chromones; D005419:Flavonoids; D015850:Interleukin-6; D009025:Morpholines; D018696:Neuroprotective Agents; D009498:Neurotoxins; D050796:STAT3 Transcription Factor; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; D050822:Cytokine Receptor gp130; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D016202:N-Methylaspartate; D019869:Phosphatidylinositol 3-Kinases; D053612:Janus Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D054510:Phospholipases A2, Cytosolic; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium