title: Amyloid precursor protein promotes endoplasmic reticulum stress-induced cell death via C/EBP homologous protein-mediated pathway.
abstract: The accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) is known to activate the ER, which is termed ER stress. Here, we demonstrated that amyloid precursor protein (APP) is a novel mediator of ER stress-induced apoptosis through the C/EBP homologous protein (CHOP) pathway. Expression of APP mRNA was elevated by tunicamycin- or dithiothreitol-induced ER stress. The levels of C83 and APP intracellular domain (AICD) fragments, which are cleaved from APP, were significantly increased under ER stress, although the protein level of full-length APP was decreased. Cellular viability was reduced in APP-over-expressing cells, which was attenuated by treatment with a gamma-secretase inhibitor, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT). Cellular viability was also reduced in AICD-FLAG-over-expressing cells. The mRNA and protein levels of CHOP, an ER stress-responsive gene, were remarkably increased by APP over-expression, which was attenuated by treatment with DAPT. CHOP mRNA induction was also found in AICD-FLAG-over-expressing cells. Cell death and CHOP up-regulation by ER stress were attenuated by APP knockdown. Data obtained with a luciferase assay and chromatin immunoprecipitation assay indicated that AICD associates with the promoter region of the CHOP gene. In conclusion, ER stress-induced APP undergoes alpha- and gamma-secretase cleavage and subsequently induces CHOP-mediated cell death.
authors.affiliation: Department of Neuroscience for Drug Discovery, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Takahashi
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Niidome
authors.forename: Akinori
authors.initials: A
authors.lastname: Akaike
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kihara
authors.forename: Hachiro
authors.initials: H
authors.lastname: Sugimoto
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line / Q000648:ultrastructure; D047369:Chromatin Immunoprecipitation / Q000379:methods; D004151:Dipeptides / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009447:Neuroblastoma; D011466:Prostanoic Acids / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013312:Stress, Physiological / Q000187:drug effects*; D013997:Time Factors; D051742:Transcription Factor CHOP / Q000378:metabolism*; D014162:Transfection; D014415:Tunicamycin / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; C497249:DDIT3 protein, human; D004151:Dipeptides; D004791:Enzyme Inhibitors; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; D011466:Prostanoic Acids; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014415:Tunicamycin; D051742:Transcription Factor CHOP; D014443:Tyrosine; D007770:L-Lactate Dehydrogenase; D004229:Dithiothreitol; C035288:rosaprostol