Characterization of V642I-AbetaPP-induced cytotoxicity in primary neurons.
Amyloid precursor protein (AbetaPP), a precursor of amyloid beta (Abeta) peptide, is one of the molecules involved in the pathogenesis of Alzheimer's disease (AD). Specific mutations in AbetaPP have been found in patients inheriting familial AD (FAD). These mutant AbetaPP proteins cause cell death in neuronal cell lines in vitro, but the molecular mechanism of cytotoxicity has not yet been clarified completely. We analyzed the cytotoxic mechanisms of the London-type AbetaPP mutant, V642I-AbetaPP, in primary cortical neurons utilizing an adenovirus-mediated gene transfer system. Expression of V642I-AbetaPP protein induced degeneration of the primary neurons. This cytotoxicity was blocked by pertussis toxin, a specific inhibitor for heterotrimeric G proteins, Go/i, and was suppressed by an inhibitor of caspase-3/7 and an antioxidant, glutathione ethyl ester. A specific inhibitor for NADPH oxidase, apocynin, but not a xanthine oxidase inhibitor or a nitric oxide inhibitor, blocked V642I-AbetaPP-induced cytotoxicity. Among mitogen-activated protein kinase (MAPK) family proteins, c-Jun N-terminal kinase (JNK) and p38MAPK, but not extracellular regulated kinase (ERK), were involved in this cytotoxic pathway. The V642I-AbetaPP-induced cytotoxicity was not suppressed by two secretase inhibitors, suggesting that Abeta does not play a major role in this cytotoxicity. Two neuroprotective factors, insulin-like growth factor I (IGF-I) and Humanin, protected these primary neurons from V642I-AbetaPP-induced cytotoxicity. Furthermore, interleukin-6 and -11 also attenuated this cytotoxicity. This study demonstrated that the signaling pathway activated by mutated AbetaPP in the primary neurons is the same as that by the other artificial insults such as antibody binding to AbetaPP and the artificial dimerization of cytoplasmic domain of AbetaPP. The potential of neurotrophic factors and cytokines in AD therapy is also indicated.
Niikura
Takako
T
Department of Pharmacology, KEIO University School of Medicine, Tokyo, Japan. niikurat@sc.itc.keio.ac.jp
Yamada
Marina
M
Chiba
Tomohiro
T
Aiso
Sadakazu
S
Matsuoka
Masaaki
M
Nishimoto
Ikuo
I
D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000633:toxicity*; D000818:Animals; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005333:Fetus; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000037:antagonists & inhibitors / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D017370:Interleukin-11 / Q000378:metabolism / Q000494:pharmacology; D015850:Interleukin-6 / Q000378:metabolism / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D008813:Mice, Inbred ICR; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D018696:Neuroprotective Agents / Q000378:metabolism / Q000494:pharmacology; D009498:Neurotoxins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D011506:Proteins / Q000378:metabolism / Q000494:pharmacology; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases
D016564:Amyloid beta-Protein Precursor; D061945:Caspase Inhibitors; D004791:Enzyme Inhibitors; D017370:Interleukin-11; D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D018696:Neuroprotective Agents; D009498:Neurotoxins; D011506:Proteins; C427211:humanin; D007334:Insulin-Like Growth Factor I; D019255:NADPH Oxidases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go