title: Exposure to dietary lipid leads to rapid production of cytosolic lipid droplets near the brush border membrane.
abstract: BACKGROUND
  Intestinal absorption of dietary lipids involves their hydrolysis in the lumen of proximal intestine as well as uptake, intracellular transport and re-assembly of hydrolyzed lipids in enterocytes, leading to the formation and secretion of the lipoproteins chylomicrons and HDL. In this study, we examined the potential involvement of cytosolic lipid droplets (CLD) whose function in the process of lipid absorption is poorly understood.
  
  
  METHODS
  Intestinal lipid absorption was studied in mouse after gavage. Three populations of CLD were purified by density ultracentrifugations, as well as the brush border membranes, which were analyzed by western-blots. Immunofluorescent localization of membranes transporters or metabolic enzymes, as well as kinetics of CLD production, were also studied in intestine or Caco-2 cells.
  
  
  RESULTS
  We isolated three populations of CLD (ranging from 15 to 1000 nm) which showed differential expression of the major lipid transporters scavenger receptor BI (SR-BI), cluster of differentiation 36 (CD-36), Niemann Pick C-like 1 (NPC1L1), and the ATP-binding cassette transporters ABCG5/G8 but also caveolin 2 and fatty acid binding proteins. The enzyme monoacylglycerol acyltransferase 2 (MGAT2) was identified in the brush border membrane (BBM) in addition to the endoplasmic reticulum, suggesting local synthesis of triglycerides and CLD at both places.
  
  
  CONCLUSIONS
  We show a very fast production of CLD by enterocytes associated with a transfer of apical constituents as lipid transporters. Our findings suggest that following their uptake by enterocytes, lipids can be partially metabolized at the BBM and packaged into CLD for their transportation to the ER.
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.
authors.forename: Zeina
authors.initials: Z
authors.lastname: Soayfane
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.
authors.forename: François
authors.initials: F
authors.lastname: Tercé
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.
authors.forename: Michela
authors.initials: M
authors.lastname: Cantiello
authors.affiliation: Leibniz-Institut für Arterioskleroseforschung, Universität Münster, Münster, Germany.
authors.forename: Horst
authors.initials: H
authors.lastname: Robenek
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.
authors.forename: Michel
authors.initials: M
authors.lastname: Nauze
authors.affiliation: UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Bézirard
authors.affiliation: INSERM UMR 1043 (INSERM/UPS/CNRS/USC Inra), CHU Purpan, Toulouse, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Allart
authors.affiliation: CMEAB, Faculté de Médecine Rangueil, Toulouse, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Payré
authors.affiliation: INSERM/UPS - US006/CREFRE, Service d'Histopathologie, CHU Purpan, Toulouse, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Capilla
authors.affiliation: UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France.
authors.forename: Christel
authors.initials: C
authors.lastname: Cartier
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.
authors.forename: Christine
authors.initials: C
authors.lastname: Peres
authors.affiliation: INSERM/UPS - US006/CREFRE, Service d'Histopathologie, CHU Purpan, Toulouse, France.
authors.forename: Talal
authors.initials: T
authors.lastname: Al Saati
authors.affiliation: UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France.
authors.forename: Vassilia
authors.initials: V
authors.lastname: Théodorou
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Nelson
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI USA.
authors.forename: Chi-Liang Eric
authors.initials: CE
authors.lastname: Yen
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Collet
authors.affiliation: Institut des Maladies Métaboliques et Cardiovasculaires - I2MC, UMR 1048, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, F-31000 France.|UMR 1331 Toxalim, INRA, Université de Toulouse, ENVT, INP-Purpan, 180 chemin de Tournefeuille, BP 93173, 31027 Toulouse, cedex 3, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Coméra
keywords: Diet and dietary lipids; Fatty acid/Metabolism; Fatty acid/Transport; Intestine; Lipid droplets