Selective modulation of amyloid-beta peptide degradation by flurbiprofen, fenofibrate, and related compounds regulates Abeta levels.
Gamma-secretase modulators (GSMs) include selected non-steroidal anti-inflammatory drugs such as flurbiprofen that selectively lowers the neurotoxic amyloid-beta peptide Abeta(1-42). GSMs are attractive targets for Alzheimer's disease, in contrast to 'inverse GSMs,' such as fenofibrate, which selectively increase the level of Abeta(1-42). A methodology for screening of Abeta modulating drugs was developed utilizing an Abeta-producing neuroblastoma cell line stably transfected with mutant human amyloid precursor protein, immunoprecipitation of Abeta peptides, and mass spectroscopic quantitation of Abeta(1-37)/Abeta(1-38)/Abeta(1-40)/Abeta(1-42) using an Abeta internal standard. The unexpected conclusion of this work was that in this system, drug effects are independent of gamma-secretase. The methodology recapitulated reported results for modulation of Abeta by GSMs. However, control experiments in which exogenous Abeta(1-40)/Abeta(1-42) was added (i) to drug-treated wild-type cells or (ii) to conditioned media from these wild-type cells, gave comparable patterns of Abeta modulation. These results, suggesting that drugs modulate the ability of cell-derived factors to degrade Abeta, was interrogated by adding protease inhibitors and performing molecular weight cut-off fractionation. The results confirmed that modulation of Abeta(1-40)/Abeta(1-42) was mediated by selective proteolysis. Treatment of N2a cells with flurbiprofen or fenofibric acid selectively enhanced Abeta(1-42) clearance by extracellular proteolysis; treatment with HCT-1026 or fenofibrate (esters of flurbiprofen and fenobric acid) inhibited clearance of Abeta(1-40) and Abeta(1-42).
Abdul-Hay
Samer O
SO
Department of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, USA.
Edirisinghe
Praneeth
P
Thatcher
Gregory R J
GR
D016229:Amyloid beta-Peptides / Q000187:drug effects* / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics; D000818:Animals; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D011345:Fenofibrate / Q000494:pharmacology*; D005480:Flurbiprofen / Q000031:analogs & derivatives / Q000494:pharmacology*; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D009447:Neuroblastoma / Q000473:pathology; D010446:Peptide Fragments / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D014162:Transfection / Q000379:methods
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; C095631:nitroflurbiprofen; D005480:Flurbiprofen; D011345:Fenofibrate