Increased duodenal expression of mi R-146a and-155 in pediatric Crohn's disease

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.

Involvement of heat shock proteins in gluten-sensitive enteropathy

Gluten-sensitive enteropathy,also known as coeliac disease(CD),is an autoimmune disorder occurring in genetically susceptible individuals that damages the small intestine and interferes with the absorption of other nutrients.As it is triggered by dietary gluten and related prolamins present in wheat,rye and barley,the accepted treatment for CD is a strict gluten-free diet.However,a complete exclusion of gluten-containing cereals from the diet is often difficult,and new therapeutic strategies are urgently needed.A class of proteins that have already emerged as drug targets for other autoimmune diseases are the heat shock proteins(HSPs),which are highly conserved stress-induced chaperones that protect cells against harmful extracellular factors.HSPs are expressed in several tissues,including the gastrointestinal tract,and their levels are significantly increased under stress circumstances.HSPs exert immunomodulatory effects,and also play a crucial role in the maintenance of epithelial cell structure and function,as they are responsible for adequate protein folding,influence the degradation of proteins and cell repair processes after damage,and modulate cell signalling,cell proliferation and apoptosis.The present review discusses the involvement of HSPs in the pathophysiology of CD.Furthermore,HSPs may represent a useful therapeutic target for the treatment of CD due to the cytoprotective,immunomodulatory,and anti-apoptotic effects in the intestinal mucosal barrier.