Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9410517 | Molecular Brain Research | 2005 | 10 Pages |
Abstract
Current understanding of IGF-I-mediated neuroprotection implies the activation of phosphatidylinositol-3-kinase (PI-3K), which leads to the activation of Akt/Protein Kinase B. In non-neuronal cells, Akt phosphorylates and activates the transcription factor CREB, implicated in the transcription of the anti-apoptotic bcl-2 gene. This paper further analyses the anti-apoptotic IGF-I action in neurons. We show that IGF-I protects cortical neurons against ceramide-induced apoptosis. Ceramide decreases Akt phosphorylation during apoptotic process whereas a simultaneous treatment with IGF-I increases Akt phosphorylation. Analysis of the signal transduction pathways revealed that IGF-I induces CREB phosphorylation via PI-3K and ERK, whereas simultaneous ceramide and IGF-I treatment decreases CREB phosphorylation. Although an overexpression of Bcl-2 protects cortical neurons against ceramide-induced apoptosis, our data indicate that the Bcl-2 protein level is not modulated during IGF-I, ceramide and/or LY294002 treatment. In consequence, we demonstrated that IGF protects neurons against ceramide-induced apoptosis and that IGF-I protection involves the PI-3K/Akt and ERK pathways; this protection may be independent of CREB and Bcl-2.
Keywords
ERKPI-3KPDK2PKCζFCSpKaIGF-Icytosine arabinosidePP2ACaMKIVCAPPJnkPC12CREBPKBBSAMTTAra-Cbovine serum albuminSDS-PAGESodium dodecyl sulfate polyacrylamide gel electrophoresisDevelopment and regenerationhorse serumfetal calf serumextracellular signal regulated kinasesInsulin-like growth factor-IPrimary culturephosphatidylinositol-3-kinaseCortexNeuronal deathSignal transductioncAMP-response element binding proteinmitogen activated protein kinaseMAP kinase
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Cellular and Molecular Neuroscience
Authors
Sandrine Willaime-Morawek, Nicolas Arbez, Jean Mariani, Bernard Brugg,