title: Chronic treatment with the gamma-secretase inhibitor LY-411,575 inhibits beta-amyloid peptide production and alters lymphopoiesis and intestinal cell differentiation.
abstract: Inhibition of gamma-secretase, one of the enzymes responsible for the cleavage of the amyloid precursor protein (APP) to produce the pathogenic beta-amyloid (Abeta) peptides, is an attractive approach to the treatment of Alzheimer disease. In addition to APP, however, several other gamma-secretase substrates have been identified (e.g. Notch), and altered processing of these substrates by gamma-secretase inhibitors could lead to unintended biological consequences. To study the in vivo consequences of gamma-secretase inhibition, the gamma-secretase inhibitor LY-411,575 was administered to C57BL/6 and TgCRND8 APP transgenic mice for 15 days. Although most tissues were unaffected, doses of LY-411,575 that inhibited Abeta production had marked effects on lymphocyte development and on the intestine. LY-411,575 decreased overall thymic cellularity and impaired intrathymic differentiation at the CD4(-)CD8(-)CD44(+)CD25(+) precursor stage. No effects on peripheral T cell populations were noted following LY-411,575 treatment, but evidence for the altered maturation of peripheral B cells was observed. In the intestine, LY-411,575 treatment increased goblet cell number and drastically altered tissue morphology. These effects of LY-411,575 were not seen in mice that were administered LY-D, a diastereoisomer of LY-411,575, which is a very weak gamma-secretase inhibitor. These studies show that inhibition of gamma-secretase has the expected benefit of reducing Abeta in a murine model of Alzheimer disease but has potentially undesirable biological effects as well, most likely because of the inhibition of Notch processing.
authors.affiliation: Department of Central Nervous System Research, Schering-Plough Research Institute, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
authors.forename: Gwendolyn T
authors.initials: GT
authors.lastname: Wong
authors.forename: Denise
authors.initials: D
authors.lastname: Manfra
authors.forename: Frederique M
authors.initials: FM
authors.lastname: Poulet
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Hubert
authors.initials: H
authors.lastname: Josien
authors.forename: Thomas
authors.initials: T
authors.lastname: Bara
authors.forename: Laura
authors.initials: L
authors.lastname: Engstrom
authors.forename: Maria
authors.initials: M
authors.lastname: Pinzon-Ortiz
authors.forename: Jay S
authors.initials: JS
authors.lastname: Fine
authors.forename: Hu-Jung J
authors.initials: HJ
authors.lastname: Lee
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Guy A
authors.initials: GA
authors.lastname: Higgins
authors.forename: Eric M
authors.initials: EM
authors.lastname: Parker
mesh_terms: D000284:Administration, Oral; D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D001921:Brain / Q000187:drug effects; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002469:Cell Separation; D010450:Endopeptidases / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D051880:Receptors, Notch; D013601:T-Lymphocytes / Q000166:cytology; D013950:Thymus Gland / Q000473:pathology; D013997:Time Factors
chemical_list: D016229:Amyloid beta-Peptides; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D010455:Peptides; D051880:Receptors, Notch; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse