Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 14, 2016; 22(26): 6027-6035
Published online Jul 14, 2016. doi: 10.3748/wjg.v22.i26.6027
Increased duodenal expression of miR-146a and -155 in pediatric Crohn’s disease
Dániel Szűcs, Nóra Judit Béres, Réka Rokonay, Kriszta Boros, Katalin Borka, Zoltán Kiss, András Arató, Attila J Szabó, Ádám Vannay, Erna Sziksz, Csaba Bereczki, Gábor Veres
Dániel Szűcs, Csaba Bereczki, Department of Pediatrics and Pediatric Health Care Center, University of Szeged, H-6725 Szeged, Hungary
Nóra Judit Béres, Zoltán Kiss, Réka Rokonay, Kriszta Boros, András Arató, Attila J Szabó, Gábor Veres, 1st Department of Pediatrics, Semmelweis University, H-1083 Budapest, Hungary
Katalin Borka, 2nd Department of Pathology, Semmelweis University, H-1091 Budapest, Hungary
Erna Sziksz, Attila J Szabó, Ádám Vannay, 1st Department of Pediatrics, Semmelweis University and MTA-SE Pediatrics and Nephrology Research Group, H-1083 Budapest, Hungary
Author contributions: Szűcs D was the gastroenterologist providing the mucosal biopsies for the study conducted by Bereczki C, Szűcs D, Béres NJ and Veres G designed the research; Arató A and Szabó AJ coordinated the research; Béres NJ, Kiss Z, Rokonay R and Boros K performed the research; Borka K performed the pathological evaluations of the biopsies; Szűcs D and Béres NJ analyzed the data; Szűcs D, Béres NJ, Sziksz E and Vannay A wrote the paper.
Supported by Hungarian Scientific Research Fund (OTKA), No. K105530, No. K108688, No. K116928, No. PD105361 and No. LP008/2016.
Institutional review board statement: The study was reviewed and approved by the Medical Research Council Scientific and Research Committee Institutional Review Board. This work was approved by TUKEB No. 10408/2012.
Conflict-of-interest statement: None of the authors have any conflict of interest or financial disclosures.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Dániel Szűcs, MD, Department of Pediatrics and Pediatric Health Care Center, University of Szeged, Hungary, Korányi fasor 14-15., H-6725 Szeged, Hungary.
Telephone: +36-62-545330 Fax: +36-62-545329
Received: March 25, 2016
Peer-review started: March 26, 2016
First decision: May 12, 2016
Revised: June 2, 2016
Accepted: June 15, 2016
Article in press: June 15, 2016
Published online: July 14, 2016

AIM: To evaluate the role of microRNA (miR)-146a, -155 and -122 in the duodenal mucosa of pediatric patients with Crohn’s disease (CD) and the effect of transforming growth factor-β (TGF-β) on these miRs in duodenal epithelial and fibroblast cells.

METHODS: Formalin-fixed, paraffin-embedded biopsies derived from the macroscopically inflamed (CD inflamed: n = 10) and intact (CD intact: n = 10) duodenal mucosa of pediatric CD patients and control children (C: n = 10) were examined. Expression of miR-146a, -155 and -122 was determined by real-time polymerase-chain reaction (PCR). The expression of the above miRs was investigated in recombinant human TGF-β (1 nmol/L, 24 h) or vehicle treated small intestinal epithelial cells (CCL-241) and primary duodenal fibroblast cells derived from healthy children as well.

RESULTS: Expression of miR-146a was significantly higher in the inflamed duodenal mucosa compared to the intact duodenal mucosa of children with CD (CD inflamed: 3.21 ± 0.50 vs CD intact: 0.62 ± 0.26, P≤ 0.01) and to the control group (CD inflamed: 3.21 ± 0.50 vs C: 1.00 ± 0.33, P≤ 0.05). The expression of miR-155 was significantly increased in the inflamed region of the duodenum compared to the control group (CD inflamed: 4.87 ± 1.02 vs Control: 1.00 ± 0.40, P≤ 0.001). The expression of miR-122 was unchanged in the inflamed or intact mucosa of CD patients compared to controls. TGF-β treatment significantly decreased the expression of miR-155 in small intestinal epithelial cells (TGF-β: 0.7 ± 0.083 vs Control: 1 ± 0.09, P≤ 0.05) and also the expression of miR-146a (TGF-β: 0.67 ± 0.04 vs Control: 1 ± 0.15, P≤ 0.01) and miR-155 (TGF-β: 0.72 ± 0.09 vs Control: 1 ± 0.06, P≤ 0.05) in primary duodenal fibroblasts compared to corresponding vehicle treated controls. TGF-β treatment did not influence the expression of miR-122.

CONCLUSION: The elevated expression of miR-146a and -155 in the inflamed duodenal mucosa of CD patients suggests the role of these miRs in the pathomechanism of inflammatory bowel disease. Anti-inflammatory TGF-β plays an important role in the regulation of the expression of these miRs.

Keywords: Inflammatory bowel disease, Crohn’s disease, Pediatric, MicroRNAs, Transforming growth factor-β

Core tip: Recent evidence suggests that besides the genetic basis, epigenetic factors including microRNAs (miRs) also act as potent inflammatory modulators during the pathogenesis of inflammatory bowel disease. MiR expression in the upper-gastrointestinal tract of pediatric patients with Crohn’s disease (CD) has not yet been analyzed. Moreover, the relation of transforming growth factor-β, playing a prominent role in the pathomechanism of CD, to miRs in this setting is also unknown. The description of precise miR patterns specific for the different segments of the gastrointestinal tract may contribute to the introduction of novel diagnostic markers and to the identification of potential therapeutic targets.