Copper depletion down-regulates expression of the Alzheimer's disease amyloid-beta precursor protein gene.
Alzheimer's disease is characterized by the accumulation of amyloid-beta peptide, which is cleaved from the amyloid-beta precursor protein (APP). Reduction in levels of the potentially toxic amyloid-beta has emerged as one of the most important therapeutic goals in Alzheimer's disease. Key targets for this goal are factors that affect the regulation of the APP gene. Recent in vivo and in vitro studies have illustrated the importance of copper in Alzheimer's disease neuropathogenesis and suggested a role for APP and amyloid-beta in copper homeostasis. We hypothesized that metals and in particular copper might alter APP gene expression. To test the hypothesis, we utilized human fibroblasts overexpressing the Menkes protein (MNK), a major mammalian copper efflux protein. MNK deletion fibroblasts have high intracellular copper, whereas MNK overexpressing fibroblasts have severely depleted intracellular copper. We demonstrate that copper depletion significantly reduced APP protein levels and down-regulated APP gene expression. Furthermore, APP promoter deletion constructs identified the copper-regulatory region between -490 and +104 of the APP gene promoter in both basal MNK overexpressing cells and in copper-chelated MNK deletion cells. Overall these data support the hypothesis that copper can regulate APP expression and further support a role for APP to function in copper homeostasis. Copper-regulated APP expression may also provide a potential therapeutic target in Alzheimer's disease.
Department of Genetics, The University of Melbourne, Parkville, Victoria 3010, Australia.
Shayne A
SA
Bellingham
Debomoy K
DK
Lahiri
Bryan
B
Maloney
Sharon
S
La Fontaine
Gerd
G
Multhaup
James
J
Camakaris
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000096:biosynthesis* / Q000235:genetics*; D000818:Animals; D015152:Blotting, Northern; D027682:Cation Transport Proteins / Q000378:metabolism; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D019295:Computational Biology; D003300:Copper / Q000378:metabolism*; D000073840:Copper-Transporting ATPases; D015536:Down-Regulation; D005347:Fibroblasts / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D017353:Gene Deletion; D005822:Genetic Vectors; D006801:Humans; D007501:Iron / Q000378:metabolism; D008253:Macaca mulatta; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D015032:Zinc / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
D016229:Amyloid beta-Peptides; D027682:Cation Transport Proteins; D010455:Peptides; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D003300:Copper; D007501:Iron; D015500:Chloramphenicol O-Acetyltransferase; D001616:beta-Galactosidase; D000251:Adenosine Triphosphatases; C081184:ATP7A protein, human; D000073840:Copper-Transporting ATPases; D015032:Zinc