P057 IL-17 regulates expression of chemotactic chemokines in human colonic subepithelial myofibroblasts

Abstract

Abstract Background Crohn’s disease (CD) and ulcerative colitis (UC), the two main entities of inflammatory bowel disease (IBD), are characterised by chronic and relapsing/remitting inflammation of the gastrointestinal tract, and occasionally ultimately result in debilitating intestinal fibrosis. Apart from their key role in fibrosis, there is evidence that subepithelial myofibroblasts (SEMFs) participate in the IBD inflammatory cascade, as they express various pro-inflammatory cytokine receptors. We examined the effect of pro-inflammatory IL-17—the hallmark cytokine of T-lymphocytes differentiated to Th17—on the expression of lymphocyte-chemotactic chemokines in SEMFs. Methods SEMFs were isolated from endoscopically obtained colonic biopsies from healthy controls, set to culture and stimulated with 100 ng/ml IL-17 for 6 h. Total RNA was extracted and mRNA expression of CCL5, CXCL1 and CXCL11 was assessed with reverse transcription quantitative (RT-q) PCR. Changes in cytokine mRNA are provided as medians (IQR). Results Untreated SEMFs had a basal expression of chemokines of the CCL and CXCL family groups. So far, our study has shown that the IL-17 stimulation leads to a statistically significant upregulation of CCL and CXCL chemokines in SEMFs (p < 0.001). In detail, CCL5 was upregulated 5.7-fold (4.9–7.5), CXCL1 72.9-fold (63.1–90.7) and CXCL11 25.4-fold (17.3–37.3). Conclusion IL-17 induced the expression of chemotactic factors in SEMFs. Our results further support a potential role of SEMFs in the shaping of intestinal mucosal immunity by serving as immunological intermediates that respond to cytokines of adaptive immunity and amplify the recruitment of immune cells via chemokine production.