Antagonistic effects of beta-site amyloid precursor protein-cleaving enzymes 1 and 2 on beta-amyloid peptide production in cells.
The deposition of extracellular beta-amyloid peptide (A beta) in the brain is a pathologic feature of Alzheimer's disease. The beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), an integral membrane aspartyl protease responsible for cleavage of amyloid precursor protein (APP) at the beta-site, promotes A beta production. A second integral membrane aspartyl protease related to BACE1, referred to as beta-site amyloid precursor protein cleaving enzyme 2 (BACE2) has also been demonstrated to cleave APP at the beta-cleavage site in transfected cells. The role of endogenous BACE2 in A beta production remains unresolved. We investigated the role of endogenous BACE2 in A beta production in cells by selective inactivation of its transcripts using RNA interference. We are able to reduce steady state levels for mRNA for each enzyme by >85%, and protein amounts by 88-94% in cells. Selective inactivation of BACE1 by RNA interference results in decreased beta-cleaved secreted APP and A beta peptide secretion from cells, as expected. Selective inactivation of BACE2 by RNAi results in increased beta-cleaved secreted APP and A beta peptide secretion from cells. Simultaneous targeting of both enzymes by RNA interference does not have any net effect on A beta released from cells. Our observations of changes in APP metabolism and A beta are consistent with a role of BACE2 in suppressing A beta production in cells that co-express both enzymes.
Basi
Guriqbal
G
Elan Pharmaceuticals, South San Francisco, California 94080,USA. guriq.basi@elan.cim
Frigon
Normand
N
Barbour
Robin
R
Doan
Tam
T
Gordon
Grace
G
McConlogue
Lisa
L
Sinha
Sukanto
S
Zeller
Michelle
M
D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D010450:Endopeptidases; D006801:Humans; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016229:Amyloid beta-Peptides; D017931:DNA Primers; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509284:BACE2 protein, human; C509280:BACE1 protein, human