Analysis of expression of vitamin E-binding proteins in H2O2induced SK-N-SH neuronal cells supplemented with α-tocopherol and tocotrienol-rich fraction

• Published in: PLoS ONE
• Main Author: Chiroma A.A.; Khaza'ai H.; Hamid R.A.; Chang S.K.; Zakaria Z.A.; Zainal Z.
• Format: Article
• Language: English
• Published: Public Library of Science 2020
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096818639&doi=10.1371%2fjournal.pone.0241112&partnerID=40&md5=fcb34a58d683c7501a6f7e56adb4ae93

Natural α-tocopherol (α-TCP), but not tocotrienol, is preferentially retained in the human body. α-Tocopherol transfer protein (α-TTP) is responsible for binding α-TCP for cellular uptake and has high affinity and specificity for α-TCP but not α-tocotrienol. The purpose of this study was to examine the modification of α-TTP together with other related vitamin Ebinding genes (i.e., TTPA, SEC14L2, and PI-TPNA) in regulating vitamin E uptake in neuronal cells at rest and under oxidative stress. Oxidative stress was induced with H2O2 for an hour which was followed by supplementation with different ratios of α-TCP and tocotrienolrich fraction (TRF) for four hours. The cellular levels of vitamin E were quantified to determine bioavailability at cellular levels. The expression levels of TTPA, SEC14L2, and PITPNA genes in 0% α-TCP were found to be positively correlated with the levels of vitamin E in resting neuronal cells. In addition, the regulation of all the above-mentioned genes affect the distribution of vitamin E in the neuronal cells. It was observed that, increased levels of α- TCP secretion occur under oxidative stress. Thus, our results showed that in conclusion vitamin E-binding proteins may be modified in the absence of α-TCP to produce tocotrienols (TCT), as a source of vitamin E. The current study suggests that the expression levels of vitamin E transport proteins may influence the cellular concentrations of vitamin E levels in the neuronal cells. © 2020 Chiroma et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.