Effects of and on serotonin transporter expression in intestinal epithelial cells.

Purpose: The highest level of peripheral serotonin in the body can be found in the gastrointestinal (GI) tract as its reservoir. There is complete interaction between human gastrointestinal microbiota and serotonin system. Serotonin in the GI is transferred by serotonin transporters (SERTs), which play a crucial role in the bioavailability of serotonin in the GI. SERT impairment is associated with the pathology of GI disorders. It is known that intestinal microbiota can regulate the SERT function. Therefore, it may be useful to regulate of SERT expression by modulation of microbiota and improvement of intestinal motility and GI sensation. In this study, we aimed to evaluate the effects of two next-generation probiotics, including and , and their supernatants on gene expression in human epithelial colorectal adenocarcinoma cells (Caco-2).

Methods: The Caco-2 cells were treated with multiplicity of infection (MOI) ratio of 100 of and , as well as their supernatants. After 24 h, gene expression was examined by quantitative real-time polymerase chain reaction (qRT-PCR) assay.

Results: up-regulated the SERT mRNA level by 3.01 folds, compared to the control group. , similar to , increased the expression of gene in Caco-2 cells by 3.43 folds ( < 0.001). Moreover, the supernatants of and significantly up-regulated the expression of gene in the cell line by 2.4 and 5.7 folds, respectively, compared to the control group ( < 0.001).

Conclusions: The present results showed that and , as well as their supernatants, increased the expression of gene in Caco-2 cells. Therefore, they might be helpful in the microbiota-modulating treatment of inflammatory bowel diseases.