Transcriptional profiling of intestinal epithelial cells in response to Enterococcus gallinarum MRx0518

In this study we describe the immunostimulatory properties of Enterococcus gallinarum MRx0518, a candidate live biotherapeutic agent with anti-tumorigenic properties. Here we demonstrate that strain MRx0518 elicits a strong pro-inflammatory response in intestinal epithelial cells. Treatments with metabolically active cells, inactivated cells or culture supernatants were found to induce distinct host responses. Microarray analysis was used to investigate and compare changes in the gene expression of intestinal epithelial cells in response to live MRx0518, heat-killed MRx0518 and MRx0518 culture supernatant. Confluent monolayers of HT29-MTX cells (ten days post seeding) were incubated with treatments of live MRx0518 and heat-killed MRx0518 at a multiplicity of infection (MOI) of 100 bacterial cells to 1 human cell, and an equivalent dilution of MRx0518 cell-free culture supernatant for 3 h at 37 °C in anaerobic conditions. Untreated cells and cells treated with bacterial culture medium (YCFA) were used as assay controls. Following incubation, RNA was isolated and hybridised to Affymetrix Human Transcriptome Array 2.0 GeneChips (GEO Accession Number GPL17586). Three independent biological replicates of each condition were carried out.