Effect of the Alzheimer amyloid fragment Abeta(25-35) on Akt/PKB kinase and survival of PC12 cells.
The phosphatidylinositol 3 kinase (PI3K)-Akt/PKB pathway protects neurons from apoptosis caused by diverse stress stimuli. However, its protective role against the amyloid beta peptide (Abeta), a major constituent of Alzheimer's disease plaques, has not been studied. We investigated the effect of the Abeta-derived Abeta(25-35) peptide on apoptosis and on the Akt survival pathway in PC12 cells. Cells submitted to micromolar concentrations of Abeta(25-35) exhibited increased production of reactive oxygen species (ROS) and morphological alterations consistent with apoptosis. Akt1 was activated shortly after incubation with Abeta(25-35) and Abeta(1-40) with a kinetics different to that of nerve-derived growth factor. Akt1 activation was blocked by the PI3K inhibitor wortmannin. We tested the hypothesis that Akt1 might modify the vulnerability of neural cells to apoptosis induced by Abeta(25-35). Overexpression of an active version of Akt1 attenuated the apoptotic effect of Abeta(25-35) as determined by flow cytometry. Moreover, PC12 cells overexpressing a membrane-targeted N-myristylated fusion protein of enhanced green fluorescence protein (EGFP) and mouse Akt1 exhibited lower levels of ROS than control EGFP-transfected cells. The present findings demonstrate that Akt1 is activated in response to Abeta(25-35) in a PI3K-dependent manner and that active Akt1 protects PC12 cells against the pro-apoptotic action of this peptide.
Martín
D
D
Departamento de Bioquímica and Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
Salinas
M
M
López-Valdaliso
R
R
Serrano
E
E
Recuero
M
M
Cuadrado
A
A
D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins; D020287:In Situ Nick-End Labeling; D007202:Indicators and Reagents / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics; D009025:Morpholines / Q000494:pharmacology; D016296:Mutagenesis / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D016716:PC12 Cells; D010446:Peptide Fragments / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014162:Transfection
D016229:Amyloid beta-Peptides; D002867:Chromones; D004791:Enzyme Inhibitors; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D009025:Morpholines; D010446:Peptide Fragments; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; C074636:amyloid beta-protein (25-35); C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C494920:Akt1 protein, rat