title: ABCA5 regulates amyloid-β peptide production and is associated with Alzheimer's disease neuropathology.
abstract: Brain cholesterol homeostasis is regulated by a group of proteins called ATP-binding cassette subfamily A (ABCA) transporters. Certain ABCA transporters regulate amyloid-β protein precursor (AβPP) processing to generate amyloid-β peptides (Aβ) and are associated with an increased risk for late-onset Alzheimer's disease (AD). ABCA5 is a little-known member of the ABCA subfamily with no known function. In this study we undertook a comprehensive analysis of ABCA5 expression in the human and mouse brains. We explored the potential role of ABCA5 in AβPP processing associated with AD pathology. ABCA5 was differentially expressed in multiple regions of both human and mouse brains. It was strongly expressed in neurons with only weak expression in microglia, astrocytes, and oligodendrocytes. ABCA5 was able to stimulate cholesterol efflux in neurons. ABCA5 expression was specifically elevated in the hippocampus of AD brains. Using two in vitro cell systems we demonstrated that ABCA5 reduces Aβ production, both Aβ40 and Aβ42, without altering AβPP mRNA and protein levels, indicating that the decrease in the Aβ levels was due to changes in AβPP processing and not AβPP expression. This report represents the first extensive expression and functional study of ABCA5 in the human brain and our data suggest a plausible function of ABCA5 in the brain as a cholesterol transporter associated with Aβ generation, information that may offer a potential new target for controlling Aβ levels in the brain.
authors.affiliation: Neuroscience Research Australia, Sydney, NSW, Australia School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
authors.forename: YuHong
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Neuroscience Research Australia, Sydney, NSW, Australia.
authors.forename: Jen-Hsiang T
authors.initials: JH
authors.lastname: Hsiao
authors.affiliation: Neuroscience Research Australia, Sydney, NSW, Australia School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
authors.forename: George
authors.initials: G
authors.lastname: Paxinos
authors.affiliation: Neuroscience Research Australia, Sydney, NSW, Australia School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Glenda M
authors.initials: GM
authors.lastname: Halliday
authors.affiliation: Neuroscience Research Australia, Sydney, NSW, Australia School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Woojin Scott
authors.initials: WS
authors.lastname: Kim
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D016466:CHO Cells; D002784:Cholesterol / Q000378:metabolism; D003412:Cricetulus; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D009457:Neuroglia / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology
chemical_list: C471294:ABCA5 protein, human; C501079:ABCA5 protein, mouse; D018528:ATP-Binding Cassette Transporters; D016229:Amyloid beta-Peptides; D002784:Cholesterol
keywords: ABC transporter; Alzheimer's disease; amyloid-β peptide; amyloid-β protein precursor; neurodegeneration; neuron