Original Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jul 21, 2013; 19(27): 4289-4299
Published online Jul 21, 2013. doi: 10.3748/wjg.v19.i27.4289
miR-20b, miR-98, miR-125b-1*, and let-7e* as new potential diagnostic biomarkers in ulcerative colitis
Mehmet Coskun, Jacob Tveiten Bjerrum, Jakob Benedict Seidelin, Jesper Thorvald Troelsen, Jørgen Olsen, Ole Haagen Nielsen
Mehmet Coskun, Jacob Tveiten Bjerrum, Jakob Benedict Seidelin, Ole Haagen Nielsen, Department of Gastroenterology, Medical Section, Herlev Hospital, University of Copenhagen, DK-2730 Herlev, Denmark
Mehmet Coskun, Jacob Tveiten Bjerrum, Jørgen Olsen, Department of Cellular and Molecular Medicine, the Panum Institute, University of Copenhagen, DK-2200 Copenhagen, Denmark
Jakob Benedict Seidelin, Department of Internal Medicine I, University of Copenhagen, Bispebjerg Hospital, DK-2400 Copenhagen NV, Denmark
Jesper Thorvald Troelsen, Department of Science, Systems, and Models, Roskilde University, DK-4000 Roskilde, Denmark
Author contributions: Coskun M and Bjerrum JT performed the experiments and data analysis, wrote the manuscript, and wrote the final revision of the article; Troelsen JT provided with analytical tools, intellectual input and advice; Olsen J provided with reagents and human tissue; Seidelin JB and Nielsen OH contributed to the conceptual design, drafting of the manuscript and revising it critically for important intellectual content; all authors approved the final submitted manuscript.
Supported by Fonden til Lægevidenskabens Fremme (the AP Møller Foundation); the Family Erichsen Memorial Foundation; and the Foundation of Aase and Ejnar Danielsen
Correspondence to: Mehmet Coskun, PhD, Department of Gastroenterology, Medical Section, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, DK-2730 Herlev, Denmark. mehmet.coskun@regionh.dk
Telephone: +45-38-683421 Fax: +45-38-684009
Received: January 11, 2013
Revised: April 15, 2013
Accepted: May 9, 2013
Published online: July 21, 2013
Processing time: 190 Days and 14.2 Hours
Abstract

AIM: To use microarray-based miRNA profiling of colonic mucosal biopsies from patients with ulcerative colitis (UC), Crohn’s disease (CD), and controls in order to identify new potential miRNA biomarkers in inflammatory bowel disease.

METHODS: Colonic mucosal pinch biopsies from the descending part were obtained endoscopically from patients with active UC or CD, quiescent UC or CD, as well as healthy controls. Total RNA was isolated and miRNA expression assessed using the miRNA microarray Geniom Biochip miRNA Homo sapiens (Febit GmbH, Heidelberg, Germany). Data analysis was carried out by principal component analysis and projection to latent structure-discriminant analysis using the SIMCA-P+12 software package (Umetrics, Umea, Sweden). The microarray data were subsequently validated by quantitative real-time polymerase chain reaction (qPCR) performed on colonic tissue samples from active UC patients (n = 20), patients with quiescent UC (n = 19), and healthy controls (n = 20). The qPCR results were analyzed with Mann-Whitney U test. In silico prediction analysis were performed to identify potential miRNA target genes and the predicted miRNA targets were then compared with all UC associated susceptibility genes reported in the literature.

RESULTS: The colonic mucosal miRNA transcriptome differs significantly between UC and controls, UC and CD, as well as between UC patients with mucosal inflammation and those without. However, no clear differences in the transcriptome of patients with CD and controls were found. The miRNAs with the strongest differential power were identified (miR-20b, miR-99a, miR-203, miR-26b, and miR-98) and found to be up-regulated more than a 10-fold in active UC as compared to quiescent UC, CD, and controls. Two miRNAs, miR-125b-1* and let-7e*, were up-regulated more than 5-fold in quiescent UC compared to active UC, CD, and controls. Four of the seven miRNAs (miR-20b, miR-98, miR-125b-1*, and let-7e*) were validated by qPCR and found to be specifically upregulated in patients with UC. Using in silico analysis we found several predicted pro-inflammatory target genes involved in various pathways, such as mitogen-activated protein kinase and cytokine signaling, which are both key signaling pathways in UC.

CONCLUSION: The present study provides the first evidence that miR-20b, miR-98, miR-125b-1*, and let-7e* are deregulated in patients with UC. The level of these miRNAs may serve as new potential biomarkers for this chronic disease.

Keywords: Biomarker; Crohn’s disease; Diagnostics; Inflammatory bowel disease; Microarray; MicroRNA; Ulcerative colitis

Core tip: This study contributes to the current knowledge on the putative role of microRNAs in inflammatory bowel disease pathogenesis, and it provides the first evidence that miR-20b, miR-98, miR-125b-1*, and let-7e* are deregulated in patients with ulcerative colitis. The level of these miRNAs may serve as new potential biomarkers for this chronic disease.