Role of STAT3 in the pathogenesis of Inflammatory Bowel Disease

描述（由申请人提供）：炎症性肠病（IBD）是结肠和小肠的特发性疾病。IBD的主要类型是克罗恩病（CD）和溃疡性结肠炎（UC）。据估计，美国有140万人患有IBD。IBD会导致严重的腹泻、腹痛，并增加患结直肠癌的风险。重要的是，IBD没有治愈方法。信号转导子和转录激活子（Stat）3已被证明在IBD小鼠模型中起致病作用。活化Stat 3水平的增加与IBD患者的肠道炎症程度直接相关。Stat 3有两种亚型（<$/p92和<$/p83）。仅表达Stat 3的小鼠对细菌LPS挑战具有高度反应性，并且对心脏、肺和肝脏内失血性休克诱导的实质细胞凋亡具有抵抗力，这表明Stat 3 ²减弱了Stat 3 ²介导的炎症和抗凋亡反应。我们以前开发了一种有效的小分子Stat 3抑制剂（C188-9），对Stat 3具有选择性。在初步研究中，我们证明C188-9几乎完全预防葡聚糖硫酸钠（DSS）诱导的小鼠结肠炎。在目前的提议中，我们将使用C188-9和转基因Stat 3小鼠来询问Stat 3有助于IBD发病机制的假设，并建立可以使用Stat 3的选择性药理学靶向治疗IBD的原理证明。我们制定了两个紧密关注的目标来检验这个假设。具体目标1：确定IBD是否可以用C188-9治疗，C188-9是一种选择性靶向Stat 3的小分子Stat 3抑制剂。我们将确定C188-9在2种慢性IBD临床前模型中是否有益-由DSS诱导的IBD（模拟UC）和由2，4，6-三硝基苯磺酸（TNBS）诱导的IBD（模拟CD）。将检查的终点包括死亡率、体重减轻、直肠出血、粪便稠度、结肠长度和结肠扩张程度。 结肠炎症（通过组织病理学评估确定）。我们还将研究C188-9抑制IBD发病机制的机制是否是通过减少免疫细胞产生促炎细胞因子和趋化因子和/或通过增加致病性CD 4 + T细胞的凋亡。具体目标2：确定Stat 3？在IBD发病机制中的作用。我们将使转基因Stat 3缺陷小鼠及其同窝野生型对照小鼠经受DSS和TNBS诱导的结肠炎，并比较疾病表现的严重程度、细胞因子和趋化因子的水平以及T细胞凋亡，如目标1所述。该提案将为以下假设提供支持：Stat 3，特别是Stat 3？，有助于IBD的发病机制，并且用对Stat 3？具有选择性的小分子抑制剂靶向Stat 3是IBD治疗的一种新的有效方法。

DESCRIPTION (provided by applicant): Inflammatory bowel disease (IBD) is an idiopathic disease of the colon and small intestine. The major types of IBD are Crohn's disease (CD) and ulcerative colitis (UC). An estimated 1.4 million persons in the United States suffer from IBD. IBD causes severe diarrhea, abdominal pain and increases the risk of colorectal cancer. Importantly, there is no cure for IBD. Signal transducer and activator of transcription (Stat) 3 ha been shown to play a pathogenic role in mice models of IBD. Increased levels of activated Stat3 directly correlated with the degree of intestinal inflammation in humans with IBD. There are two isoforms of Stat3 (¿/p92 and ¿/p83). Mice expressing only Stat3¿ are hyper-responsive to bacterial LPS challenge and are resistant to hemorrhagic shock-induced apoptosis of parenchymal cells within the heart, lung, and liver suggesting that Stat3¿ attenuates inflammatory and anti-apoptotic responses mediated by Stat3¿. We previously developed a potent, small-molecule Stat3 inhibitor (C188-9) that is selective for Stat3¿ vs. Stat3¿. In preliminary studies, we demonstrated that C188-9 almost completely prevents dextran sodium sulphate (DSS)-induced colitis in mice. In the current proposal, we will use C188-9 and transgenic Stat3¿ mice to interrogate the hypothesis that Stat3¿ contributes to the pathogenesis of IBD and to establish proof-of-principle that IBD can be treated using selective pharmacological targeting of Stat3¿. We have formulated 2 tightly focused aims to examine this hypothesis. Specific aim 1: To determine if IBD can be treated with C188-9, a small-molecule inhibitor of Stat3 that selectively targets Stat3¿. We will determine if C188-9 is of benefit in 2 preclinical models of chronic IBD-IBD induced by DSS, which mimics UC, and IBD induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS), which mimics CD. Endpoints that will be examined include mortality rate, weight loss, rectal bleeding, stool consistency, colon length and extent of colonic inflammation (as determined by histopathological assessment). We will also examine if the mechanism by which C188-9 inhibits the pathogenesis of IBD is through decreasing the production of proinflammatory cytokines and chemokines by immunocytes and/or through increased apoptosis of pathogenic CD4+T-cells. Specific aim 2: To determine the contribution of Stat3¿ to the pathogenesis of IBD. We will subject transgenic Stat3¿ knock-in/Stat¿-deficient mice and their littermate WT controls to DSS- and TNBS-induced colitis and compare the severity of disease manifestations, levels of cytokines and chemokines and T-cell apoptosis as outlined in Aim 1. This proposal will provide support for the hypothesis that Stat3, particularly Stat3¿, contributes to the pathogenesis of IBD and that targeting Stat3 with a small molecule inhibitor that is selective for Stat3¿ is a novel and effective approach to IBD treatment.