The Effects of Retinoic Acid on the Expression of HNF4α and Cdx-2 Genes in Caco-2 Cells as a Model of Intestinal Barrier

Retinoic acid (RA) is involved in protecting the intestinal barrier, inducing differentiation, growth and proliferation of epithelial cells. There are several hypotheses about the mechanism of induction of apoptosis by RA, but few studies have been performed on the role of HNF4α and Cdx-2 in intestinal cells. The aim of this study was to evaluate the survival and expression of these two genes following administration of RA in Caco-2 cells as a model of intestinal epithelial cells.

In the present study, Caco-2 cells were used and exposed to retinoic acid at concentrations of 10, 20, and 40 μM for 72 hours. After incubation for 24 and 48 hours, these samples were assigned to evaluate the effects of cytotoxicity by measuring mitochondrial enzyme activity using the MTT method. The expression levels of HNF4α and Cdx-2 genes at the mRNA level were examined by real-time PCR technique.

The results showed that 48 hours after adding 20 and 40 μM RA, the number of cells decreased in a concentration-dependent manner. In the first 24 and 48 hours, the dependence on the expression concentration of the HNF4α gene increased, and in contrast, the expression of the Cdx-2 gene decreased during these hours. Based on the results obtained during the 72 hours of the study, the expression levels of the genes decreased compared to those in the control which was due to the reduction of living cells and disruption of cellular homeostasis.

Use of RA in high concentrations can cause disruption of intestinal homeostasis due to an imbalance between the two genes. Therefore, concentration of retinoic acid derivatives should be selected according to the purpose of treatment.