P002 Epithelial to mesenchymal transition is a hallmark of fibrostenosing Crohn's disease and is associated with down regulation of the miR-200 family. (16th January 2018)

• Record Type: Journal Article
• Authors: Mehta, S J; Lewis, A; Nijhuis, A; Jeffery, R; Feakins, R; Silver, A; Lindsay, J O
• Is Part Of: Journal of Crohn's and colitis. Volume 12:Number 1(2018:Jan.)Supplement 1
• Page Start: S091
• Page End: S092
• Publication Date: 2018-01-16
• Subjects: Inflammatory bowel diseases -- Periodicals; 616.344005
• DOI: 10.1093/ecco-jcc/jjx180.129
• Languages: English
• ISSNs: 1873-9946

Abstract

Abstract: Background: Intestinal mesenchymal cells are responsible for extracellular matrix deposition leading to fibrosis in Crohn's disease (CD). Epithelial to mesenchymal transition (EMT) contributes to renal fibrosis 1 but the role in intestinal fibrosis remains obscure. The miR-200 family of microRNA (miRNA) gene regulators has been shown to control EMT 2 . In this study we document The presence of EMT in CD, correlate this with the degree of fibrosis and measure miR-200 expression in intestinal tissue compartments. Methods: Immunohistochemical (IHC) staining patterns of epithelial (cytokeratin-18) and mesenchymal (vimentin) cell markers on paired intestinal strictured (SCD) and non-strictured (NSCD) FFPE ileal resection specimens from CD patients were analysed using standardised thresholds in ImageJ. The severity and extent of fibrosis and inflammation in each sample were graded "blind" by a pathologist. Tissue compartments from FFPE SCD and NSCD sections were isolated by laser capture microdissection. RT-qPCR was performed using total RNA and miRNA extracted from whole tissue and tissue compartments. Results: Extra-epithelial cell cytokeratin-18 staining was significantly greater in SCD compared with NSCD samples (0.19% v 0.06%; p = 0.04; n = 9). The vimentin positive epithelial cell area was significantly greater in SCD compared with NSCD samples (3.13% v 1.35%; p = 0.03; n = 9). Total fibrosis scores were higher in SCD samples ( p = 0.02); total ulcer scores were not significantly different ( p = 0.54). A positive correlation was observed between extra-epithelial cytokeratin-18 staining and subserosal fibrosis ( R 2 =0.66; p = 0.0004). Four members of the miR-200 family were significantly downregulated in fresh whole SCD samples (miR-141, p = 0.002; -200a, p = 0.002; -200c, p = 0.001; -429; p = 0.004). The reduced miRNA expression was localised to the epithelium of SCD samples ( p = 0.001-0.015) with only miR-200b downregulated in the submucosa ( p = 0.043); no smooth muscle miRNA expression change was found. The miR-200 target ZEB1 was upregulated in SCD compared with NSCD samples (fold change 9.8; p = 0.035; n = 9). A positive correlation was seen between epithelial miR-141 expression and subserosal fibrosis scores in all samples ( R 2 =0.75; p = 0.02; n = 6). Conclusions: IHC staining in SCD tissue was consistent with populations of epithelial cells migrating into deeper layers and gaining mesenchymal characteristics, suggestive of EMT. The correlation with fibrosis scores suggests EMT is a functionally relevant mechanism driving fibrosis in CD and occurs independently of inflammation. The miR-200 family are implicated as regulators of this process given the epithelial-specific dysregulation and tissue upregulation of downstream effectors. Functional studies to prove this relationship are warranted. References: 1. Sun YB. The origin of renal fibroblasts/myofibroblasts and the signals that trigger fibrosis. Differentiation, 2016;92:102–107. 2. Chen Y. MiR-200b inhibits TGF-β1-induced epithelial-mesenchymal transition and promotes growth of intestinal epithelial cells. Cell Death Dis, 2013;4:541.