MiR-19b downregulates intestinal SOCS3 to reduce intestinal inflammation in Crohn's disease.

Xiuqin Cheng,Jun Zhou,Xiaofei Zhang,Cheng Wang,Ke Zen,Yingdi Zhang,Jiewen Su,Hongjie Zhang,Hongwei Liang,Xi Chen,Chen-Yu Zhang,Ruihua Shi,Weimei Zhou

doi:10.1038/srep10397

Abstract

Although aberrant microRNA (miRNA) expression has frequently been observed in inflammatory bowel disease (IBD), its biological functions and targets remain largely unknown. Present study found that miR-19b was significantly downregulated in active Crohn’s disease (CD). Using bioinformatics analysis, suppressor of cytokine signalling 3 (SOCS3), a physiological regulator of innate and adaptive immunity that controls several immuno-inflammatory diseases, was predicted to be a potential target of miR-19b. An inverse correlation between miR-19b and SOCS3 protein levels, but not mRNA, was identified in active-CD intestinal tissue samples. By overexpressing or knocking down miR-19b in Caco2 cells and HT29 cells, it was experimentally validated that miR-19b is a direct regulator of SOCS3. Using a luciferase reporter assay, it was confirmed that miR-19b directly recognizes the 3’-untranslated region (3’-UTR) of SOCS3. Furthermore, overexpression of miR-19b decreased SOCS3 expression, leading to increased production of macrophage-inflammatory protein-3α (MIP-3α) in Caco2 cells. In contrast, knockdown of miR-19b increased SOCS3 and decreased MIP-3α. Finally, intracolonically delivered miR-19b decreased the severity of colitis induced with 2,4,6-trinitrobenzene sulphonic acid (TNBS). Taken together, our findings suggest that miR-19b suppresses the inflammatory response by inhibiting SOCS3 to modulate chemokine production in intestinal epithelial cells (IECs) and thereby prevents the pathogenesis of CD.

Highlights

Inflammatory bowel disease (IBD) is characterized by chronic recurring gastrointestinal inflammation, primarily classified into two major phenotypes: Crohn’s disease (CD) and ulcerative colitis (UC)
IHC analysis revealed that suppressor of cytokine signalling 3 (SOCS3) protein was highly expressed in the intestinal mucosa of active CD patients compared to normal controls, especially in the epithelial layer (Fig. 1a)
Based on Western blot analysis, SOCS3 protein was intensely expressed in the inflamed jejunum, ileum and colon mucosa of CD patients, whereas this expression was barely detectable in normal colon mucosa; there was no difference in SOCS3 expression between the jejunum, ileum and colon in CD patients (Fig. 1b)

Summary

Introduction

Inflammatory bowel disease (IBD) is characterized by chronic recurring gastrointestinal inflammation, primarily classified into two major phenotypes: Crohn’s disease (CD) and ulcerative colitis (UC). Various cytokines are involved in innate and adaptive immune regulation, and dysregulation of cytokine signalling contributes to heightened inflammation and diseases such as autoimmune disease[3]. SOCS proteins are key physiological regulators of innate and adaptive immunity and control immuno-inflammatory disease development[5,6]. Because SOCS3 regulates multiple cytokine signalling pathways, it may be a useful therapeutic target for autoimmune disease[9,10]. It is important to understand what molecules regulate SOCS3 expression to identify potential therapeutic targets for anti-inflammatory therapies. Differential expression of miRNAs and their roles in epithelial disruption during IBD remain unclear. We hypothesized that intestinal epithelia disruption is linked to abnormal SOCS3 expression and that miRNAs regulate this abnormal expression during intestinal inflammation

Methods

Results

Conclusion