title: Inhibitors of cathepsin B improve memory and reduce beta-amyloid in transgenic Alzheimer disease mice expressing the wild-type, but not the Swedish mutant, beta-secretase site of the amyloid precursor protein.
abstract: Elucidation of Abeta-lowering agents that inhibit processing of the wild-type (WT) beta-secretase amyloid precursor protein (APP) site, present in most Alzheimer disease (AD) patients, is a logical approach for improving memory deficit in AD. The cysteine protease inhibitors CA074Me and E64d were selected by inhibition of beta-secretase activity in regulated secretory vesicles that produce beta-amyloid (Abeta). The regulated secretory vesicle activity, represented by cathepsin B, selectively cleaves the WT beta-secretase site but not the rare Swedish mutant beta-secretase site. In vivo treatment of London APP mice, expressing the WT beta-secretase site, with these inhibitors resulted in substantial improvement in memory deficit assessed by the Morris water maze test. After inhibitor treatment, the improved memory function was accompanied by reduced amyloid plaque load, decreased Abeta40 and Abeta42, and reduced C-terminal beta-secretase fragment derived from APP by beta-secretase. However, the inhibitors had no effects on any of these parameters in mice expressing the Swedish mutant beta-secretase site of APP. The notable efficacy of these inhibitors to improve memory and reduce Abeta in an AD animal model expressing the WT beta-secretase APP site present in the majority of AD patients provides support for CA074Me and E64d inhibitors as potential AD therapeutic agents.
authors.affiliation: Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Neurosciences, University of California, San Diego, La Jolla, California 92093, USA. vhook@ucsd.edu
authors.forename: Vivian Y H
authors.initials: VY
authors.lastname: Hook
authors.forename: Mark
authors.initials: M
authors.lastname: Kindy
authors.forename: Gregory
authors.initials: G
authors.lastname: Hook
mesh_terms: D000544:Alzheimer Disease / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002401:Cathepsin B / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D004151:Dipeptides / Q000494:pharmacology* / Q000627:therapeutic use; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D015870:Gene Expression; D006801:Humans; D007930:Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects; D051379:Mice; D008822:Mice, Transgenic
chemical_list: D016564:Amyloid beta-Protein Precursor; C400541:CA 074 methyl ester; D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D053829:Amyloid Precursor Protein Secretases; D002401:Cathepsin B; D007930:Leucine; C108192:aloxistatin