title: Akt-dependent expression of NAIP-1 protects neurons against amyloid-{beta} toxicity.
abstract: Neurotrophins are a family of growth factors that attenuate several forms of pathological neuronal cell death and may represent a putative therapeutic approach to neurodegenerative diseases. In Alzheimer disease, amyloid-beta (Abeta) is thought to play a central role in the neuronal death occurring in brains of patients. In the present study, we evaluate the ability of neurotrophin-3 (NT-3) to protect neurons against the toxicity induced by aggregated Abeta. We showed that in primary cultures of cortical neurons, NT-3 reduces Abeta-induced apoptosis by limiting caspase-8, caspase-9, and caspase-3 cleavage. This neuroprotective effect of NT-3 was concomitant to an increased level of Akt phosphorylation and was abolished by an inhibitor of the phosphatidylinositol-3 kinase (PI-3K), LY294002. In parallel, NT-3 treatment reduced Abeta induced caspase-3 processing to control levels. In an attempt to link PI-3K/Akt to caspase inhibition, we evaluated the influence of the PI-3K/Akt axis on the expression of a member of the inhibitors of apoptosis proteins (IAPs), the neuronal apoptosis inhibitory protein-1. We demonstrated that NT-3 induces an up-regulation of neuronal apoptosis inhibitory protein-1 expression in neurons that promotes the inhibition of Abeta-induced neuronal apoptosis. Together, these findings demonstrate that NT-3 signaling counters Abeta-dependent neuronal cell death and may represent an innovative therapeutic intervention to limit neuronal death in Alzheimer disease.
authors.affiliation: UMR CNRS 6185, Université de Caen, Bd. H. Becquerel BP5229, 14074 Caen, France and Howard Hughes Medical Institute, Rutgers University, Piscataway, New Jersey 08854, USA.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Lesné
authors.forename: Cecilia
authors.initials: C
authors.lastname: Gabriel
authors.forename: Deirdre A
authors.initials: DA
authors.lastname: Nelson
authors.forename: Eileen
authors.initials: E
authors.lastname: White
authors.forename: Eric T
authors.initials: ET
authors.lastname: Mackenzie
authors.forename: Denis
authors.initials: D
authors.lastname: Vivien
authors.forename: Alain
authors.initials: A
authors.lastname: Buisson
mesh_terms: D016229:Amyloid beta-Peptides / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D003720:Densitometry; D004305:Dose-Response Relationship, Drug; D004587:Electrophoresis, Agar Gel / Q000379:methods; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D051379:Mice; D008856:Microscopy, Fluorescence; D009025:Morpholines / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000378:metabolism / Q000502:physiology*; D051616:Neuronal Apoptosis-Inhibitory Protein; D009474:Neurons / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D016229:Amyloid beta-Peptides; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D002867:Chromones; D004247:DNA; D004791:Enzyme Inhibitors; D009025:Morpholines; D009419:Nerve Tissue Proteins; D051616:Neuronal Apoptosis-Inhibitory Protein; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; C496801:Naip1 protein, mouse; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; C506434:Casp9 protein, mouse