New Insights on Fat-Soluble Vitamin Efflux by the Intestine
Date: July 16 2020
Presenter(s): Emmanuelle Reboul, PhD
Summary:
Efficient intestinal absorption of dietary fat-soluble vitamins is required in most people to ensure an adequate status. However, fat-soluble vitamin absorption process is more complex than previously thought and our understanding of the molecular mechanisms responsible for their uptake and efflux at the brush-border level has substantially progressed over the past decade. We recently investigated the involvement of ATP-binding cassette B1 (ABCB1, P-glycoprotein) in fat-soluble vitamin intestinal efflux. Interestingly, vitamin D, E and K apical effluxes were decreased by chemical inhibition of ABCB1 in Caco-2 cells and increased by ABCB1 overexpression in Griptites or MDCKII cells. The involvement of ABCB1 in vitamin transport was further confirmed in Abcb1-/- mice. We also highlighted that a trans-intestinal efflux of vitamin D could occur and that it was partly mediated by ABCB1. ABCB1 thus appear as a key protein in fat-soluble vitamin transport as it is involved in neo-absorbed vitamin efflux by the enterocytes, and that it may also contribute to their transintestinal excretion and impact on their status. Identifying other proteins involved in intestinal uptake and transport of fat-soluble vitamins across the intestinal cells, as well as understanding their molecular functioning, is of major importance. Indeed, some of these proteins are already targets for the development of drugs able to reduce cholesterol or lipid absorption and these drugs may also interfere with fat-soluble vitamin uptake. A better understanding of the molecular mechanisms involved in fat-soluble vitamin absorption is a priority to better optimize their bioavailability.
About the presenter:
REBOUL Emmanuelle, PhD
Head of the research axis “Bioavailability of Micronutrients” in the “Human Micronutrition” team of the “Cardiovascular and Nutrition Center of Marseille, France
Biography
Dr. Emmanuelle Reboul received an Engineer diploma in Nutrition and Food Sciences from Agrosup Dijon, France in 2002. During her master degree and PhD thesis in the INSERM* laboratory “Human Nutrition and Lipids” in Marseille, France, she studied carotenoid, vitamin A and E intestinal absorption. She then joined the working group of Dr. R.S. Molday in 2006 at the University of British Columbia in Vancouver, Canada to work on ATP transporter molecular functioning.
Back to Marseille, France since the end of 2008 in the “Nutrition, Obesity and Risk of Thrombosis” laboratory as a permanent INRA** Researcher, she currently focuses on fat-soluble micronutrient intestinal absorption and membrane transport. Her group was the first one in the Word to discover a fat-soluble micronutrient membrane transporter at the intestinal level and still has a leading position on this topic.
She has received several awards for her work including the PhD award of the French Lipidomic Group (2007), the Price of the French Academia of Medicine (2007), the Pepsico International Travel Price (2009), and the Research Prices of the French Nutrition Society (2010 and 2015).
