Effects of Grape Seed-derived Polyphenols on Amyloid β-Protein Self-assembly and Cytotoxicity*,♦
- Kenjiro Ono‡§,1,
- Margaret M. Condron‡,
- Lap Ho¶∥,
- Jun Wang¶,
- Wei Zhao¶,
- Giulio M. Pasinetti¶∥,2 and
- David B. Teplow‡,3
- ‡Department of Neurology, David Geffen School of Medicine, and Molecular Biology Institute and Brain Research Institute, University of California, Los Angeles, California 90095, the §Department of Neurology and Neurobiology and Aging, Kanazawa University Graduate School of Medical Science, Kanazawa 920-8640, Japan, the ¶Department of Psychiatry and Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, and the ∥Bronx Veterans Administration Medical Center, Bronx, New York 10468
- ↵2 To whom correspondence may be addressed: Mount Sinai School of Medicine, 1468 Madison Ave., Rm. 14-94C, NY, NY 10029-6574. E-mail: giulio.pasinetti{at}mssm.edu. 3 To whom correspondence may be addressed: Dept. of Neurology, 635 Charles E. Young Dr. South (Rm. 445), Los Angeles, CA 90095-7334; E-mail: dteplow{at}ucla.edu.
Abstract
Epidemiological evidence suggests that moderate consumption of red wine reduces the incidence of Alzheimer disease (AD). To study the protective effects of red wine, experiments recently were executed in the Tg2576 mouse model of AD. These studies showed that a commercially available grape seed polyphenolic extract, MegaNatural-AZ (MN), significantly attenuated AD-type cognitive deterioration and reduced cerebral amyloid deposition (Wang, J., Ho, L., Zhao, W., Ono, K., Rosensweig, C., Chen, L., Humala, N., Teplow, D. B., and Pasinetti, G. M. (2008) J. Neurosci. 28, 6388–6392). To elucidate the mechanistic bases for these observations, here we used CD spectroscopy, photo-induced cross-linking of unmodified proteins, thioflavin T fluorescence, size exclusion chromatography, and electron microscopy to examine the effects of MN on the assembly of the two predominant disease-related amyloid β-protein alloforms, Aβ40 and Aβ42. We also examined the effects of MN on Aβ-induced cytotoxicity by assaying 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide metabolism and lactate dehydrogenase activity in Aβ-treated, differentiated pheochromocytoma (PC12) cells. Initial studies revealed that MN blocked Aβ fibril formation. Subsequent evaluation of the assembly stage specificity of the effect showed that MN was able to inhibit protofibril formation, pre-protofibrillar oligomerization, and initial coil → α-helix/β-sheet secondary structure transitions. Importantly, MN had protective effects in assays of cytotoxicity in which MN was mixed with Aβ prior to peptide assembly or following assembly and just prior to peptide addition to cells. These data suggest that MN is worthy of consideration as a therapeutic agent for AD.
Footnotes
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↵* This work was supported, in whole or in part, by National Institutes of Health Grant PO1 AT004511 through the NCCAM (to L. H., G. M. P., and D. B. T.) and Grant AG027818 (to (D. B. T.). This work also was supported by the Department of Veterans Affairs Merit Review grant and a grant from the James J. Peters Veterans Affairs Medical Center Geriatric Research Education Clinical Center Program, and Polyphenolics (to G. M. P.); grants from the Japan Human Science Foundation and the Mochida Memorial Foundation for Medical and Pharmaceutical Research (to K. O.); and grants from the Alzheimer's Association, and the Jim Easton Consortium for Alzheimer's Drug Discovery and Biomarkers at UCLA (to D. B. T.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵♦ This article was selected as a Paper of the Week.
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The on-line version of this article (available at http://www.jbc.org) contains a supplemental figure.
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↵1 Supported by a Pergolide Fellowship from Eli Lilly Japan.
- Received August 8, 2008.
- Revision received September 17, 2008.
- The American Society for Biochemistry and Molecular Biology, Inc.
