The effect of oxidized cholesterol on barrier functions and IL-10 mRNA expression in human intestinal epithelium co-cultured with dendritic cells in the transwell system

The intestinal epithelium is exposed to oxygenated cholesterol products present in foodstuffs. In vitro studies demonstrate the effect of oxysterols on cytokine release by intestinal cells cultured alone. However, physiologically, the response of the intestinal epithelium to external agents occurs in the presence of dendritic cells (DCs). The aim of the study was to analyze the effect of 7-ketocholesterol on the barrier functions and IL-10 mRNA expression of Caco-2 cells in the presence of DCs, and secondly, on IL-10 mRNA expression in DCs. Caco-2 cells were co-cultured with monocyte-derived dendritic cells and induced with 7-ketocholesterol in a transwell system. DCs did not affect the transepithelial electrical resistance (TER) of the Caco-2 cell monolayer, but increased IL-10 mRNA expression in Caco-2 cells. 7-ketocholesterol decreased the TER of Caco-2 cells co-cultured with DCs and diminished IL-10 mRNA expression in Caco-2 cells induced by the presence of DCs. IL-10 mRNA expression fell in DCs co-cultured with Caco-2 cells after treatment with 7-ketocholesterol. Oxidized cholesterols present in gut mucosa may contribute to the decrease of epithelial barrier functions and the inappropriate development of an inflammatory response to food compounds.