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DiPasquale M, Nguyen MHL, Rickeard BW, Cesca N, Tannous C, Castillo SR, Katsaras J, Kelley EG, Heberle FA, Marquardt D. The antioxidant vitamin E as a membrane raft modulator: Tocopherols do not abolish lipid domains. Biochim Biophys Acta Biomembr 2020; 1862:183189. [PMID: 31954106 PMCID: PMC10443432 DOI: 10.1016/j.bbamem.2020.183189] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 01/06/2023]
Abstract
The antioxidant vitamin E is a commonly used vitamin supplement. Although the multi-billion dollar vitamin and nutritional supplement industry encourages the use of vitamin E, there is very little evidence supporting its actual health benefits. Moreover, vitamin E is now marketed as a lipid raft destabilizing anti-cancer agent, in addition to its antioxidant behaviour. Here, we studied the influence of vitamin E and some of its vitamers on membrane raft stability using phase separating unilamellar lipid vesicles in conjunction with small-angle scattering techniques and fluorescence microscopy. We find that lipid phase behaviour remains unperturbed well beyond physiological concentrations of vitamin E (up to a mole fraction of 0.10). Our results are consistent with a proposed line active role of vitamin E at the domain boundary. We discuss the implications of these findings as they pertain to lipid raft modification in native membranes, and propose a new hypothesis for the antioxidant mechanism of vitamin E.
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Affiliation(s)
- Mitchell DiPasquale
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario,Canada
| | - Michael H L Nguyen
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario,Canada
| | - Brett W Rickeard
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario,Canada
| | - Nicole Cesca
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario,Canada
| | - Christopher Tannous
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario,Canada
| | - Stuart R Castillo
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario,Canada
| | - John Katsaras
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
| | - Elizabeth G Kelley
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | | | - Drew Marquardt
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario,Canada; Department of Physics, University of Windsor, Windsor, Ontario, Canada.
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