Cationic lipids (lipofectamine) and disturbance of cellular cholesterol and sphingomyelin distribution modulates gamma-secretase activity within amyloid precursor protein in vitro.
To study beta-amyloid protein generation we expressed different amyloid precursor protein (APP) isoforms in the human neuroblastoma cell line SY5Y (for details see (1)). Treatment with lipofectamine, an cationic lipid for eucaryotic cell transfection, inhibits gamma-secretase activity and stimulates the physiological APP cleavage by alpha-secretase activity. Beside the MDL inhibitor (2), this is the second agent that shows modulation of gamma-secretase activity in vitro. Further, we show that disturbance of cellular cholesterol and sphingomyelin distribution in transfected SY5Y cells results in an overproduction of beta-amyloid protein. This provides experimental evidence that membrane instability influenced the proteolytic activity of gamma-secretase within the APP molecule.
Urmoneit
B
B
University of Düsseldorf, Department of Neurology, Germany. britta@atax.neu.uni-duesseldorf.de
Turner
J
J
Dyrks
T
T
D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000096:biosynthesis*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D016282:Aspartic Acid Endopeptidases; D001665:Binding Sites; D002411:Cation Exchange Resins / Q000494:pharmacology*; D002451:Cell Compartmentation / Q000187:drug effects; D002784:Cholesterol / Q000378:metabolism; D010450:Endopeptidases / Q000187:drug effects*; D006801:Humans; D008055:Lipids / Q000494:pharmacology*; D008954:Models, Biological; D009417:Nerve Tissue / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011994:Recombinant Proteins / Q000378:metabolism; D013109:Sphingomyelins / Q000378:metabolism; D014407:Tumor Cells, Cultured
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D002411:Cation Exchange Resins; D008055:Lipids; C086724:Lipofectamine; D009842:Oligopeptides; D011480:Protease Inhibitors; D011994:Recombinant Proteins; D013109:Sphingomyelins; D002784:Cholesterol; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human