Abstract
Some nonsteroidal anti-inflammatory drugs has been shown to allosterically modulate the activity of γ-secretase, the enzymatic complex responsible for the formation of β-amyloid (Aβ). 1-(3′,4′-Dichloro-2-fluoro[1,1′-biphenyl]-4-yl)-cyclopropanecarboxylic acid (CHF5074) is a new γ-secretase modulator, devoid of anticyclooxygenase (COX) and Notch-interfering activities in vitro. We evaluated the effects of chronic CHF5074 treatment on brain Aβ pathology in Tg2576 transgenic mice. Twenty-eight animals of 9.5 to 10.5 months of age received CHF5074-medicated diet (375 ppm) or standard diet for 17 weeks. Compared with controls, CHF5074 treatment significantly reduced the area occupied by plaques and the number of plaques in cortex (–52.2 ± 5.6%, p = 0.0003 and –48.9 ± 6.6%, p = 0.0004, respectively) and hippocampus (–76.7 ± 6.4%, p = 0.004 and –66.2 ± 10.3%, p = 0.037, respectively). Biochemical analysis confirmed the histopathological measures, with CHF5074-treated animals showing reduced total brain Aβ40 (–49.2 ± 9.2%, p = 0.017) and Aβ42 (–43.5 ± 9.7%, p = 0.027) levels. In a human neuroglioma cell line expressing Swedish mutated form of amyloid precursor protein (H4swe), CHF5074 reduced Aβ42 and Aβ40 secretion, with an IC50 of 3.6 and 18.4 μM, respectively, values consistent with those measured in the brain of the CHF5074-treated Tg2576 mice (6.4 ± 0.4 μM). At 5 μM, no effects were observed on Notch intracellular cleavage in human embryonic kidney 293swe cells. CHF5074 was well tolerated by Tg2576 mice. No abnormal findings were observed upon histopathological examination of the gastrointestinal tract, indicating the absence of COX-related toxicity. Semiquantitative histochemical evaluation of goblet cells in the ileum of vehicle- and CHF5074-treated animals yielded similar results, suggesting no effects on Notch pathway. CHF5074 is therefore a promising therapeutic agent for Alzheimer's disease.
Footnotes
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The work was sponsored by Chiesi Farmaceutici, Parma, Italy. A part of this study was presented at the 8th International Conference on Alzheimer's and Parkinson's Diseases; 2007 March 14–18; Salzburg, Austria.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.107.129007.
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ABBREVIATIONS: AD, Alzheimer's disease; Aβ, β-amyloid peptide; APP, amyloid precursor protein; NSAID, nonsteroidal anti-inflammatory drug; COX, cyclooxygenase; CHF5074, 1-(3′,4′-dichloro-2-fluoro[1,1′-biphenyl]-4-yl)-cyclopropanecarboxylic acid; APPswe, Swedish mutated form of APP; H4swe, human neuroglioma cell line expressing APPswe; HEK293swe, human embryonic kidney 293 cells expressing APPswe; FA, formic acid; ELISA, enzyme-linked immunosorbent assay; GFAP, glial fibrillar acidic protein; MRK-560, N-[cis-4-[(4-chlorophenyl)sulfonyl]-4-(2,5-difluorophenyl)cyclohexyl]-1,1,1-trifluoromethane sulfonamide.
- Received July 20, 2007.
- Accepted September 24, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
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