title: Presenilin-dependent gamma-secretase activity modulates neurite outgrowth.
abstract: Demonstration that cleavage of both APP and Notch are dependent on the product of the early onset Alzheimer's disease gene, presenilin-1 (PS1), has raised the possibility that Notch function may be altered in AD. This finding also suggests that Notch may be affected by APPgamma-secretase inhibitors under development for the treatment of Alzheimer's disease, as these target PS1. Data that address these questions have been lacking, due to inability to specifically modulate PS1 activity in a system directly relevant to the adult human brain. Using novel highly specific inhibitors of PS1/gamma-secretase, we demonstrate that modulation of PS1 activity in human CNS neurons not only affects Abeta generation, but also has unanticipated effects on Notch and its activity. We demonstrate that intracellular trafficking of Notch in human CNS neurons is altered by inhibition of PS1 and is accompanied by dramatic changes in neurite morphology, consistent with inhibition of Notch activity. These data, together with immunohistochemical evidence of elevation of Notch pathway expression in AD brain, suggest that Notch dysregulation may contribute to the neuritic dystrophy characteristically seen in Alzheimer's disease brain. In addition, they raise the possibility that inhibition of gamma-secretase/PS1 may have clinically beneficial effects on the neuritic pathology of AD, in addition to its expected effect to reduce amyloid burden.
authors.affiliation: Department of Neuroscience, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Figueroa
authors.forename: Jill A
authors.initials: JA
authors.lastname: Morris
authors.forename: Lei
authors.initials: L
authors.lastname: Ma
authors.forename: Geeta
authors.initials: G
authors.lastname: Kandpal
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Chen
authors.forename: Yue-Ming
authors.initials: YM
authors.lastname: Li
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Austin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology; D053829:Amyloid Precursor Protein Secretases; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000032:analysis; D002219:Carbamates / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D000072261:Dishevelled Proteins; D010450:Endopeptidases / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3; D006056:Golgi Apparatus / Q000378:metabolism; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008253:Macaca mulatta; D008565:Membrane Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000473:pathology / Q000502:physiology*; D009447:Neuroblastoma; D010750:Phosphoproteins / Q000032:analysis; D053764:Presenilin-1; D011480:Protease Inhibitors / Q000494:pharmacology; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002219:Carbamates; D004151:Dipeptides; D000072261:Dishevelled Proteins; C410009:L 685458; D008565:Membrane Proteins; C497761:NOTCH1 protein, human; C508853:PSEN1 protein, human; D010750:Phosphoproteins; D053764:Presenilin-1; D011480:Protease Inhibitors; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D014157:Transcription Factors; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human