Pro-inflammatory miR-223 mediates the cross-talk between the IL23 pathway and the intestinal barrier in inflammatory bowel disease

Wang et al. Genome Biology (2016)7:58 DOI 10.1186/s13059-016-0901-8 RESEARCH Open Access Pro-inflammatory miR-223 mediates the cross-talk between the IL23 pathway and the intestinal barrier in inflammatory bowel disease Huiling Wang1, Kang Chao1, Siew Chien Ng2, Alfa Hc Bai2, Qiao Yu1, Jun Yu2, Manying Li1, Yi Cui1, Minhu Chen1*, Ji-Fan Hu3,4* and Shenghong Zhang1* Abstract Background: The IL23/Th17 pathway is essential for the onset of inflammatory bowel disease (IBD), yet the specific mechanism by which this pathway initiates the disease remains unknown. In this study, we identify the mechanisms that mediate cross-talk between the IL23 pathway and the intestinal barrier in IBD. Results: The downstream targets of the IL23 pathway were identified by RNA array profiling and confirmed by immunohistochemical staining. The role of miRNAs that interact with IL23 was explored in mice with TNBS-induced colitis. Claudin-8 (CLDN8), a multigene family protein that constitutes the backbone of tight junctions, was identified as a novel target of IL23 in IBD. CLDN8 was significantly downregulated in IBD patients with inflamed colonic mucosa, and in trinitrobenzene sulphonic acid (TNBS) induced colitis in mice. Therapeutic treatment of colitis in mice using an IL23 antibody restored CLDN8 abundance, in parallel with recovery from colitis. In addition, we identify miR-223 as a novel mediator of the crosstalk between the IL23 signal pathway and CLDN8 in the development of IBD. MiR-223 was upregulated in IBD, and its activity was regulated through the IL23 pathway. Antagomir inhibition of miR-223 reactivated CLDN8 and improved a number of signs associated with TNBS-induced colitis in mice. Conclusions: Our study characterizes a new mechanistic pathway in IBD, in which miR-223 interacts with the IL23 pathway by targeting CLDN8. Strategies designed to disrupt this interaction may provide novel therapeutic agents for the management of IBD. Keywords: Crohn’s disease, Ulcerative colitis, Interleukin 23, miRNA, Pathway Background Inflammatory bowel disease (IBD) comprises two distinct phenotypes: ulcerative colitis (UC) and Crohn’s disease (CD), each of which has unique clinical manifestations while sharing many genetic and mechanistic features [1, 2]. In the past decade, the incidence of IBD in Asia has increased dramatically. Our recent population-based study showed that Guangzhou and Hong Kong are among the * Correspondence: ; ; 1 Division of Gastroenterology, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan Road 2, Guangzhou 510080, P.R. China 3 Stem Cell and Cancer Center, First Hospital, Jilin University, Changchun, P.R. China Full list of author information is available at the end of the article top three cities in Asia with the highest incidence of IBD at 3.44 and 3.06 per 100,000, respectively [3]. Although the exact pathophysiology of IBD is not fully understood, the etiology of this disease is known to be multifactorially driven by a number of genetic and environmental factors, including loss of regulation of the host’s innate immune response and defects in mucosal barrier function [4]. The intestinal epithelial barrier is crucial for maintaining the intestinal homoeostasis because of its location between the luminal bacteria and the host’s innate immune system. This epithelial barrier represents the first exposure to various external environmental factors, which can trigger the onset of various diseases, including © 2016 Wang et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Wang et al. Genome Biology (2016)7:58 IBD [5]. Tight junctions (TJs) are the main components of the intestinal epithelial barrier, and they function primarily in controlling cellular polarity and adhesion [6]. The components of the tight junction include Occludin, Tricellulin [7], the junctional adhesion molecule (JAM) proteins [8], and the large Claudin family. The Claudins, consisting of 24–27 members in mammalian genomes, are the major determinant of electrolyte permeability through the paracellular pathway, and are regarded as the backbone of the intestinal barrier [9]. Claudins have been reported to be dysregulated in IBD patients. Recent studies have found that the IL23/Th17 axis is involved in the regulation of IBD [10, 11]. Inhibition of the pathway by anti-IL23P19 monoclonal antibody attenuated Trinitrobenzene sulfonic acid (TNBS)-induced Crohn’s disease in rats [12]. Although both the dysfunction of intestinal barrier properties and the IL23/Th17 pathway are key contributors to the onset of IBD, it is still not clear whether there exists a link between these two factors in mediating the chronic inflammation of IBD. MiRNAs are small non-coding RNAs that regulate gene expression by base pairing with target mRNAs at the 3’-untranslated region, leading to mRNA cleavage and translational repression [13, 14]. It has been suggested that miRNAs regulate tens or hundreds of targets [15], and a number of biological processes are regulated by miRNAs, including cell proliferation, cell death, stress resistance, and differentiation of intestinal epithelial cells [16, 17]. It has also been reported that the expression of miRNAs is abnormal in IBD patients, suggesting that the altered expression of miRNAs may be involved in pathogenesis of IBD [18, 19]. However, the role of miRNAs in the IL23 pathway has not been explored. Previous studies found that cytokines, including TNFα, might induce or inhibit the expression of miRNAs [20, 21]. Therefore, we hypothesized that the IL23 pathway might interact with miRNAs to cause dysfunction of the intestinal epithelial barrier. In this study, we sought to identify the downstream targets of the IL23 pathway in the development of IBD, including those miRNAs that mediate the cross-talk between the IL23/Th17 axis and the intestinal epithelial barrier. Results The role of the IL23 pathway in TNBS-induced colitis The IL23/Th17 pathway is critical to the onset of IBD. To delineate the mechanisms underlying the role of IL23 in IBD, we established a colitis model in BALB/c mice using TNBS, and treated these mice with antiIL23P19 mAb. The animals with colitis that were treated with anti-IL23P19 (TNBS + P19) experienced a significant recovery in body weight compared to the isotype control group (TNBS + ISO) (Fig. 1a). In addition, the Page 2 of 15 anti-IL23P19 treatment improved many cardinal signs of colitis in (...truncated)