Differential effects of ethanol antagonism and neuroprotection in peptide fragment NAPVSIPQ prevention of ethanol-induced developmental toxicity
- Michael F. Wilkemeyer*,†,‡,§,
- Shao-yu Chen§,¶,∥,
- Carrie E. Menkari*,†,‡,
- Douglas E. Brenneman**,
- Kathleen K. Sulik¶,∥, and
- Michael E. Charness*,†,‡,††
- *Neurology Service, Veterans Affairs Boston Healthcare System, West Roxbury, MA 02132; †Department of Neurology, Harvard Medical School, Boston, MA 02115; ‡Department of Neurology, Brigham and Women's Hospital, Boston, MA 02115; ¶Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC 27599; ∥Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC 27599; and **Section on Developmental and Molecular Pharmacology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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Edited by Solomon H. Snyder, The Johns Hopkins University School of Medicine, Baltimore, MD (received for review March 21, 2003)
Abstract
NAPVSIPQ (NAP), an active fragment of the glial-derived activity-dependent neuroprotective protein, is protective at femtomolar concentrations against a wide array of neural insults and prevents ethanol-induced fetal wastage and growth retardation in mice. NAP also antagonizes ethanol inhibition of L1-mediated cell adhesion (ethanol antagonism). We performed an Ala scanning substitution of NAP to determine the role of ethanol antagonism and neuroprotection in NAP prevention of ethanol embryotoxicity. The Ser-Ile-Pro region of NAP was crucial for both ethanol antagonism and protection of cortical neurons from tetrodotoxin toxicity (neuroprotection). Ala replacement of either Ser-5 or Pro-7 (P7A-NAP) abolished NAP neuroprotection but minimally changed the efficacy of NAP ethanol antagonism. In contrast, Ala replacement of Ile-6 (I6A-NAP) caused a decrease in potency (>2 logarithmic orders) with only a small reduction (<10%) in the efficacy of NAP neuroprotection but markedly reduced the efficacy (50%) and the potency (5 logarithmic orders) of NAP ethanol antagonism. Ethanol significantly reduced the number of paired somites in mouse whole-embryo culture; this effect was prevented significantly by 100 pM NAP or by 100 pM P7A-NAP, but not by 100 pM I6A-NAP. The structure–activity relation for NAP prevention of ethanol embryotoxicity was similar to that for NAP ethanol antagonism and different from that for NAP neuroprotection. These findings support the hypothesis that NAP antagonism of ethanol inhibition of L1 adhesion plays a central role in NAP prevention of ethanol embryotoxicity and highlight the potential importance of ethanol effects on L1 in the pathophysiology of fetal alcohol syndrome.
Footnotes
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↵ †† To whom correspondence should be addressed at: Department of Neurology (127), Harvard Medical School, Veterans Affairs Boston Healthcare System, 1400 VFW Parkway, West Roxbury, MA 02132. E-mail: mcharness{at}hms.harvard.edu.
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↵ § M.F.W. and S.-y.C. contributed equally to this work.
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This paper was submitted directly (Track II) to the PNAS office.
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Abbreviations: FAS, fetal alcohol syndrome; TTX, tetrodotoxin; NAP, peptide fragment NAPVSIPQ; SAL, peptide fragment SALLRSIPA.
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See commentary on page 8043.
- Copyright © 2003, The National Academy of Sciences
