The proteome of cytosolic lipid droplets isolated from differentiated Caco-2/TC7 enterocytes reveals cell-specific characteristics

• DOI: 10.1042/bc20110024
• Publication Date: 2011-07-28T08:46:12Z
• Authors: Julien Bouchoux; Frauke Beilstein; Thomas Pauquai; I. Chiara Guerrera; Danielle Chateau; Nathalie Ly; Malik Alqub; Christophe Klein; Jean Chambaz; Monique Rousset; Jean-Marc Lacorte; Etienne Morel; Sylvie Demignot
• Keywords: Proteome; Enterocyte; Lipid droplet; Caco-2

Intestinal absorption of alimentary lipids is a complex process ensured by enterocytes and leading to TRL [TAG (triacylglycerol)-rich lipoprotein] assembly secretion. The accumulation circulating intestine-derived associated with atherosclerosis, stressing the importance control postprandial hypertriglyceridaemia. During period, TAGs are also transiently stored as CLDs (cytosolic lipid droplets) in enterocytes. As first step for determining whether could play role enterocyte secretion, we analysed protein endowment isolated sucrose-gradient centrifugation from differentiated Caco-2/TC7 enterocytes, only human model able secrete culture store when supplied lipids. Cells were after 24 h incubation micelles thus state CLD-associated TAG mobilization.Among 105 proteins identified CLD fraction LC-MS/MS (liquid chromatography coupled tandem MS), 27 directly involved metabolism pathways potentially relevant enterocyte-specific functions. transient feature was consistent presence necessary fatty acid activation (acyl-CoA synthetases) hydrolysis. In time LPCAT2 (lysophosphatidylcholine acyltransferase 2), PC (phosphatidylcholine) synthesis, 3BHS1 (3-β-hydroxysteroid dehydrogenase 1), steroid metabolism, confirmed their partial localization immunofluorescence. may provide an economical source PC, membrane synthesis lipoprotein assembly, lysoPC present intestinal lumen. We such ApoA-IV (apolipoprotein A-IV), which specifically expressed has been proposed many functions vivo, including formation lipoproteins size. association confocal immunoelectron microscopy validated vivo jejunum mice fed high-fat diet.We report CLDs. Our results suggest that mobilization participate secretion cell-specific manner.