P009 The innate cytokines IL-1α and TNF-α induce the expression of Oncostatin M and its type II receptor in human colonic subepithelial myofibroblasts

Abstract

Abstract Background Oncostatin M (OSM), a cytokine of the IL-6 family, has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Specifically, OSM and its receptor, OSMR, are elevated in inflamed colonic regions of IBD patients; in addition, high OSM expression at baseline has been associated with failure to respond to anti-TNF. OSMR expression localised in stromal cells of the intestinal lamina propria. Our aim was to investigate the expression of OSM and its receptors subunits, OSMR, LIFR and gp-130 in primary subepithelial myofibroblasts (SEMFs) and test whether this expression is regulated by the innate cytokines, IL-1α and TNF-α. Methods Primary SEMFs were isolated from endoscopically-obtained colonic biopsies from healthy controls, set to culture and stimulated with 5ng/ml IL-1α and/or 50ng/ml TNF-α for 6 h. Total RNA was extracted and the mRNA transcripts for OSM, OSMR, LIFR and gp-130 were measured by reverse transcription-quantitative (RT-q) PCR. Results Unstimulated SEMFs had a basal expression of both OSM and its receptors subunits. IL-1α or TNF-α stimulations did not alter LIFR expression, but they induced a statistically significant upregulation of OSM, OSMR and gp-130. Specifically, the expression of OSM in SEMFs was significantly upregulated after stimulation with IL-1α alone or in combination with TNF-α (IL-1α: 11.48-fold increase, 8.29–26.05; IL-1α+TNF-α: 13.42-fold, 11.32–17.16; p < 0.0001). Regarding the OSMR and gp-130 subunits [which form the type II receptor of OSM], OSMR mRNA was induced by TNF-α alone or in combination with IL-1α (TNF-α: 1.75-fold, 1.27–2.02, p < 0.01; IL-1α+TNF-α: 2.06-fold, 1.83–2.34, p < 0.0001), whereas gp-130 mRNA expression was increased under all stimulatory conditions (IL-1α: 1.94-fold, 1.46–2.07; TNF-α: 1.81-fold, 1.46–2.25; IL-1α+TNF-α: 1.59-fold, 1.31–2.51; p < 0.01 for all comparisons). Conclusion Our results show that OSM and OSMR are expressed on primary human SEMFs and that they are upregulated under stimulation with innate pro-inflammatory cytokines. These data further support a potential role of this system of inflammatory mediators in the pathogenesis of intestinal inflammation.