Effect of Lactobacillus plantarum MB452 on the gene expression of the intestinal epithelial cell line Caco-2

The hypothesis of this research was that probiotic bacteria that increase intestinal barrier function achieve this, partly, by increasing the expression of the genes involved in tight junction signalling in healthy intestinal epithelial cells. L. plantarum MB452 isolated from the probiotic product VSL#3 was chosen as the test bacterium because it has a robust, repeatable, positive effect tight junction integrity, as measured by the trans-epithelial electrical resistance (TEER) in vitro. Gene expression was compared in Caco-2 cells untreated or treated with L. plantarum MB452 for 10 hours. An equal amount of Caco-2 cell RNA from three wells of the same treatment was pooled together to yield enough RNA for the gene expression analysis; two control pools and two pools treated with L. plantarum MB452. Caco-2 cell RNA was hybridised to human oligonucleotide arrays (Agilent). Data was analysed using linear models (Limma package in Bioconductor) and differently expressed genes were examined using pathway analysis tools (Gene Ontology categories, KEGG pathways using EASE and Ingenuity Pathway Analysis).