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Differentiated human intestinal Caco-2 cells are frequently used in toxicology and pharmacology as in vitro models for studies on intestinal barrier functions. Since several discrepancies exist among the different lines and clones of Caco-2 cells, comparison of the results obtained and optimisation of models for use for regulatory purposes are particularly difficult, especially with respect to culture conditions and morphological and biochemical parameters. An inter-laboratory study has been performed on the parental cell line and on three clonal Caco-2 cell lines, with the aim of standardising the culture conditions and identifying the best cell line with respect to parameters relevant to barrier integrity, namely, transepithelial electrical resistance (TEER) and mannitol passage, and of epithelial differentiation (alkaline phosphatase activity). Comparison of the cell lines maintained in traditional serum-supplemented culture medium or in defined medium, containing insulin, transferrin, selenium and lipids, showed that parameter performance was better and more reproducible with the traditional medium. The maintenance of the cell lines for 15 days in culture was found to be sufficient for the development of barrier properties, but not for full epithelial differentiation. Caco-2/TC7 cells performed better than the other three cell lines, both in terms of reproducibility and performance, exhibiting low TEER and mannitol passage, and high alkaline phosphatase activity.

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Béaslas O, Torreilles F, Casellas P, Simon D, Fabre G, Lacasa M, Delers F, Chambaz J, Rousset M, Carrière V. Transcriptome response of enterocytes to dietary lipids: impact on cell architecture, signaling, and metabolism genes. Am J Physiol Gastrointest Liver Physiol 295: G942-G952, 2008. First published August 28, 2008 doi:10.1152/ajpgi.90237.2008.-Intestine contributes to lipid homeostasis through the absorption of dietary lipids, which reach the apical pole of enterocytes as micelles. The present study aimed to identify the specific impact of these dietary lipid-containing micelles on gene expression in enterocytes. We analyzed, by microarray, the modulation of gene expression in Caco-2/TC7 cells in response to different lipid supply conditions that reproduced either the permanent presence of albumin-bound lipids at the basal pole of enterocytes or the physiological delivery, at the apical pole, of lipid micelles, which differ in their composition during the interprandial (IPM) or the postprandial (PPM) state. These different conditions led to distinct gene expression profiles. We observed that, contrary to lipids supplied at the basal pole, apical lipid micelles modulated a large number of genes. Moreover, compared with the apical supply of IPM, PPM specifically impacted 46 genes from three major cell function categories: signal transduction, lipid metabolism, and cell adhesion/architecture. Results from this first large-scale analysis underline the importance of the mode and polarity of lipid delivery on enterocyte gene expression. They demonstrate specific and coordinated transcriptional effects of dietary lipid-containing micelles that could impact the structure and polarization of enterocytes and their functions in nutrient transfer.nutrients; alimentary lipids; mRNA; intestine THE EXPANSION OF METABOLIC diseases (obesity, metabolic syndrome, and diabetes), and the subsequent atherosclerosis and cardiovascular diseases, are linked to the important changes in dietary habits that have occurred during the last decades, among which is an increase in fat intake (45). Although this impairment of energy homeostasis has been largely analyzed, little attention has been paid to the role that the intestine could play in this process. This organ is the first to face nutrients and may therefore contribute actively to these pathologies through the control of absorption, metabolism, and delivery of dietary lipids.Enterocytes represent the major cell population of the intestinal epithelium. As absorptive cells (31), they ensure the delivery of dietary lipids through a highly polarized process, from absorption at the apical pole of enterocytes to secretion at their basolateral pole toward lymph then general circulation (for review, see Ref. 33). Dietary lipids, mostly triglycerides (TG), are supplied to enterocytes as complex micelles resulting from their hydrolysis by pancreatic enzymes, into fatty acids (FA) and monoglycerides (MG), and their solubilization by biliary salts and lipids in the intestinal lumen. After ab...