title: Development of a high-throughput screen targeting caspase-8-mediated cleavage of the amyloid precursor protein.
abstract: Caspases, effectors of apoptosis, are key mediators of neuronal death in several neurodegenerative diseases. Caspase-8 and caspase-6 have been implicated in the pathogenesis of amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, and Alzheimer's disease (AD). ß-Amyloid precursor protein (APP) is cleaved at Asp664 in its intracellular domain by caspase-8. We and other laboratories recently showed that obliteration of the caspase cleavage site on APP alleviates functional AD-like deficits in a mouse model. Therefore, caspase cleavage of APP constitutes a potential novel target for therapeutic intervention. To identify chemical inhibitors of caspase-8 cleavage, we screened a subset of the chemical library at the Harvard NeuroDiscovery Center's Laboratory for Drug Discovery in Neurodegeneration. We show that caspase-8, but not caspase-1, -3, or -9, cleaves a biotinylated peptide derived from APP at Asp664, and we report the development of a sensitive high-throughput assay for caspase-8 cleavage of APP and the use of that assay for the identification of specific small molecule "hit" compounds that potently inhibit Asp664 cleavage of APP. Furthermore, we demonstrate that one of these compounds (LDN-0021835) inhibits the cleavage of APP at Asp664 in cell-based assays.
authors.affiliation: Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Hart
authors.forename: Marcie
authors.initials: M
authors.lastname: Glicksman
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Mohit K
authors.initials: MK
authors.lastname: Sharma
authors.forename: Greg
authors.initials: G
authors.lastname: Cuny
authors.forename: Veronica
authors.initials: V
authors.lastname: Galvan
mesh_terms: D000595:Amino Acid Sequence; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D015153:Blotting, Western; D053181:Caspase 8 / Q000378:metabolism*; D057166:High-Throughput Screening Assays; D006801:Humans; D008969:Molecular Sequence Data; D059748:Proteolysis
chemical_list: D016564:Amyloid beta-Protein Precursor; D053181:Caspase 8