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ABCG1 is involved in vitamin E efflux

Olivier, Maryline, Bott, Romain, Frisdal, Eric, Nowicki, Marion, Plengpanich, Wanee, Desmarchelier, Charles, Roi, Stéphanie, Quinn, Carmel M., Gelissen, Ingrid, Jessup, Wendy, Van Eck, Miranda, Guérin, Maryse, Le Goff, Wilfried, Reboul, Emmanuelle
BBA - Molecular and Cell Biology of Lipids 2014 v.1841 pp. 1741-1751
cholesterol, gamma-tocopherol, hepatocytes, humans, lipoproteins, liver, macrophages, mice, physiological transport, rats, tissues, transporters
Vitamin E membrane transport has been shown to involve the cholesterol transporters SR-BI, ABCA1 and NPC1L1. Our aim was to investigate the possible participation of another cholesterol transporter in cellular vitamin E efflux: ABCG1. In Abcg1-deficient mice, vitamin E concentration was reduced in plasma lipoproteins whereas most tissues displayed a higher vitamin E content compared to wild-type mice. α- and γ-tocopherol efflux was increased in CHO cells overexpressing human ABCG1 compared to control cells. Conversely, α- and γ-tocopherol efflux was decreased in ABCG1-knockdown human cells (Hep3B hepatocytes and THP-1 macrophages). Interestingly, α- and γ-tocopherol significantly downregulated ABCG1 and ABCA1 expression levels in Hep3B and THP-1, an effect confirmed in vivo in rats given vitamin E for 5days. This was likely due to reduced LXR activation by oxysterols, as Hep3B cells and rat liver treated with vitamin E displayed a significantly reduced content in oxysterols compared to their respective controls. Overall, the present study reveals for the first time that ABCG1 is involved in cellular vitamin E efflux.