title: Restoring blood-brain barrier P-glycoprotein reduces brain amyloid-beta in a mouse model of Alzheimer's disease.
abstract: Reduced clearance of amyloid-beta (Abeta) from brain partly underlies increased Abeta brain accumulation in Alzheimer's disease (AD). The mechanistic basis for this pathology is unknown, but recent evidence suggests a neurovascular component in AD etiology. We show here that the ATP-driven pump, P-glycoprotein, specifically mediates efflux transport of Abeta from mouse brain capillaries into the vascular space, thus identifying a critical component of the Abeta brain efflux mechanism. We demonstrate in a transgenic mouse model of AD [human amyloid precursor protein (hAPP)-overexpressing mice; Tg2576 strain] that brain capillary P-glycoprotein expression and transport activity are substantially reduced compared with wild-type control mice, suggesting a mechanism by which Abeta accumulates in the brain in AD. It is noteworthy that dosing 12-week-old, asymptomatic hAPP mice over 7 days with pregnenolone-16alpha-carbonitrile to activate the nuclear receptor pregnane X receptor restores P-glycoprotein expression and transport activity in brain capillaries and significantly reduces brain Abeta levels compared with untreated control mice. Thus, targeting intracellular signals that up-regulate blood-brain barrier P-glycoprotein in the early stages of AD has the potential to increase Abeta clearance from the brain and reduce Abeta brain accumulation. This mechanism suggests a new therapeutic strategy in AD.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Minnesota Medical School, Duluth, MN 55812, USA.
authors.forename: Anika M S
authors.initials: AM
authors.lastname: Hartz
authors.forename: David S
authors.initials: DS
authors.lastname: Miller
authors.forename: Björn
authors.initials: B
authors.lastname: Bauer
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000199:Actins / Q000378:metabolism; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D001812:Blood-Brain Barrier; D002196:Capillaries / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D010446:Peptide Fragments / Q000378:metabolism; D058255:Protease Nexins; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000199:Actins; D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D010446:Peptide Fragments; D058255:Protease Nexins; D011956:Receptors, Cell Surface; C075222:amyloid beta-protein (1-42)