MDR1-P-Glycoprotein (ABCB1) Mediates Transport of Alzheimer's amyloid-beta peptides--implications for the mechanisms of Abeta clearance at the blood-brain barrier.
Amyloid-beta (Abeta) is the major component of the insoluble amyloid plaques that accumulate intracerebrally in patients with Alzheimer's disease (AD). It has been suggested that MDR1-P-glycoprotein (ABCB1, P-gp) plays a substantial role in the elimination of Abeta from the brain. In the present study, MDR1-transfected LLC cells growing in a polarized cell layer were used to characterize the interaction of Abeta1-40/1-42 with P-gp. In this system, P-gp-mediated transport can be followed by the efflux of the fluorescent dye rhodamine-123, or of Abeta itself from the cells into the apical extracellular space. Abeta significantly decreased the apical efflux of rhodamine-123, and the transcellular transport of Abeta1-40 and Abeta1-42 into the apical chamber could be demonstrated using both ELISA and fluorescence (FITC)-labeled peptides. This transport was inhibited by a P-gp modulator. Furthermore, ATP-dependent, P-gp-mediated transport of the fluorescence-labeled peptides could be demonstrated in isolated, inside-out membrane vesicles. Our data support the concept that P-gp is important for the clearance of Abeta from brain, and thus may represent a target protein for the prevention and/or treatment of neurodegenerative disorders such as AD.
Kuhnke
Diana
D
Department of Pharmacology, Research Center of Pharmacology and Experimental Therapeutics, Ernst-Moritz-Arndt-University, Greifswald, Germany.
Jedlitschky
Gabriele
G
Grube
Markus
M
Krohn
Markus
M
Jucker
Mathias
M
Mosyagin
Igor
I
Cascorbi
Ingolf
I
Walker
Lary C
LC
Kroemer
Heyo K
HK
Warzok
Rolf W
RW
Vogelgesang
Silke
S
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism*; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002451:Cell Compartmentation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D018374:LLC-PK1 Cells; D008657:Metabolic Clearance Rate / Q000502:physiology; D010446:Peptide Fragments / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D020112:Rhodamine 123 / Q000378:metabolism; D013552:Swine; D014162:Transfection; D022161:Transport Vesicles / Q000378:metabolism
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D010455:Peptides; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); D020112:Rhodamine 123