Characterization and Targeting of MiR-24 Network in Colitis

项目摘要 microRNA是小的非编码RNA分子，其与不同的肿瘤的发病机制有关。 人类炎症性疾病。最近的证据表明，操纵microRNA的表达， 在不同病因的炎性疾病中具有治疗潜力。我们和其他人已经确定， microRNA在炎症性肠病（IBD）中失调;然而，它们的作用和功能 在IBD病理生理学中重要性还没有很好地理解。我们的初步证据显示，miR-24 在2组溃疡性结肠炎（UC）的结肠活检组织中， 克罗恩病（CD）患者或其他GI疾病（肠易激综合征、结直肠癌）患者。 此外，相对于正常人，活动性UC患者的结肠活检组织中miR-24表达更高。 UC缓解期患者。尽管已经发现几种microRNA在不同的细胞中被失调， 胃肠道（GI）疾病，我们的结果表明miR-24在UC中特异性失调， 提示在UC发病机制中的重要作用。microRNA领域的一个关键问题是鉴定 它们的直接基因靶点。在这里，我们遵循了一个公正的综合计算和分子分析 并发现miR-24可能通过调节一个由以下基因组成的基因网络参与UC发病机制： 炎症（HFN4A-PPAR γ-NF-κ B）回路，并通过直接靶向HNFA和肠通透性控制 通过直接调节claudin-7，影响ERK和MMP信号通路，因此这些 数据表明，miR-24调节炎症和上皮通透性，这两个方面都是UC的关键方面， 发病机制另一方面，HNF4A和/或claudin-7增强的miR-24的抑制增加了 表达式，表明存在反馈回路网络。这是第一个描述 microRNA作为炎症反应和肠道通透性的变阻器，通过调节 反馈回路网络在这里，我们将研究一个新的假设，即miR-24网络发挥重要作用， 通过调节炎症和肠通透性机制在UC病理生理学中发挥作用。基于 强有力的初步调查结果以下目标将解决这一总体假设。目标1将评估以下方面的作用： miR-24-HNF4A网络控制UC中的炎症反应。目标2将描述 miR-24影响肠上皮通透性的分子机制使用人UC患者组织将 确认目标1和2中的调查结果与统一通信的相关性。目的3将检测miR-16的治疗潜力。 通过施用新的化学稳定的miR-24抑制剂（UCDI-1）， 实验性结肠炎（体内）和来自UC患者的新鲜分离的结肠外植体（离体）。理解 miR-24分子网络不仅将提供关于miR-24在UC病理生理学中的作用的新见解， 但它也可能决定UC中UCDI-1抑制miR-24的治疗潜力。

PROJECT SUMMARY MicroRNAs are small non-coding RNA molecules that have been implicated in the pathogenesis of different human inflammatory diseases. Recent evidence indicates that manipulation of microRNA expression could have therapeutic potential in inflammatory diseases of different etiologies. We and others have identified that microRNAs are deregulated in Inflammatory Bowel Disease (IBD); however their role and functional importance in IBD pathophysiology is not well understood. Our preliminary evidence revealed that miR-24 expression is specifically up-regulated in colonic biopsies from 2 cohorts of ulcerative colitis (UC), but not Crohn's disease (CD) patients or patients with other GI diseases (irritable bowel syndrome, colorectal cancer). Furthermore, miR-24 expression is higher in colonic biopsies from UC patients with active disease relative to UC patients in remission. Although several microRNAs have been found to be deregulated in different gastrointestinal (GI) diseases, our results demonstrate that miR-24 is specifically deregulated in UC, suggesting an important role in UC pathogenesis. A key question in the microRNA field is the identification of their direct gene targets. Here, we have followed an unbiased integrative computational and molecular analysis and found that miR-24 is potentially involved in UC pathogenesis by regulating a gene network consisting of an inflammatory (HFN4A-PPARγ-NF-κB) circuit by targeting directly HNFA, and an intestinal permeability control mechanism, by modulating directly claudin-7, which affects the ERK and MMP signaling pathways. Thus, these data suggest that miR-24 regulates inflammation and epithelial permeability, both key aspects of UC pathogenesis. On the other hand, suppression of HNF4A and/or claudin-7 reinforced miR-24 increased expression, suggesting the presence of a feedback loop network. This is the first evidence describing a microRNA to act as a rheostat of the inflammatory response and intestinal permeability, through regulation of a feedback loop network. Here, we will examine the novel hypothesis that the miR-24 network plays an important role in UC pathophysiology by regulating inflammatory and intestinal permeability mechanisms. Based on strong preliminary findings the following aims will address this overall hypothesis. Aim 1 will evaluate the role of miR-24 – HNF4A network on controlling the inflammatory responses in UC. Aim 2 will characterize the molecular mechanism of miR-24 on intestinal epithelial permeability. Use of human UC patient tissues will confirm the UC relevance of the findings in aims 1 and 2. Aim 3 will examine the therapeutic potential of miR- 24 inhibition, by administering a novel chemically-stable miR-24 inhibitor (UCDI-1), in mouse models of experimental colitis (in vivo) and in freshly isolated colonic explants from UC patients (ex vivo). Understanding the miR-24 molecular network will not only provide novel insights on the role of miR-24 in UC pathophysiology, but it may also determine the therapeutic potential of miR-24 inhibition by UCDI-1 in UC.