Epithelial to Mesenchymal Transition and Fibrosis in Inflammatory Bowel Disease

炎症性肠病中的上皮间质转化和纤维化

• 批准号: 8111479
• 负责人: Sarah Nicole Flier
• 金额: $ 15.05万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8111479
• 关键词: Address; Anti-Inflammatory Agents; Anti-Tumor Necrosis Factor Therapy; Anti-inflammatory; Apoptosis; Attenuated; Biochemical; Cell Lineage; Cell Separation; Cells; Characteristics; Chronic; Chronic Disease; Colitis; Complement; Complication; Confocal Microscopy; Crohn' s disease; Data; Deposition; Epithelial; Epithelial Cells; Extracellular Matrix; Fibroblasts; Fibrosis; Fistula; Genetic; Heart; Human; In Vitro; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Intervention; Intestinal Fibrosis; Intestines; Kidney; LacZ Genes; Lamina Propria; Lead; Liver; Mediating; Mesenchymal; Methods; Modeling; Molecular; Mouse Protein; Mus; Obstruction; Operative Surgical Procedures; Organ; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Population Heterogeneity; Process; Property; Proteins; Receptor Signaling; Recombinants; Recruitment Activity; Recurrent disease; Reporter; Role; Rosa; Shapes; Signal Pathway; Signal Transduction; Signaling Molecule; Site; Smooth Muscle Actin Staining Method; Source; Stem cells; Sulfonic Acids; Therapeutic Effect; Therapeutic Intervention; Time; Tissues; Transforming Growth Factors; Transgenic Mice; Transgenic Organisms; Treatment Efficacy; Trinitrobenzenes; Ulcerative Colitis; Wound Healing; base; bone morphogenetic protein 7; bone morphogenic protein; clinically significant; design; epithelial to mesenchymal transition; fibrogenesis; in vivo; insight; intestinal epithelium; large bowel Crohn' s disease; mouse model; novel; prevent; receptor; research study; transcription factor; villin

DESCRIPTION (provided by applicant): Intestinal fibrosis in the form of fistula and fibrostenotic strictures is a major complication of inflammatory bowel disease, particularly Crohn's disease (CD). Over 1/3 of patients with CD require surgery to relieve obstruction associated with fibrotic strictures and many require repeat interventions because of recurrent disease. Although some medications are available to target the robust inflammatory processes characteristic of CD, little is known about the mechanism of intestinal fibrosis and there are no specific therapies for this common and exceedingly morbid complication. Intestinal fibrosis is thought to follow a common pathway of fibrogenesis, as seen in other organs, in which activated fibroblasts are recruited to sites of inflammation for the purpose of wound healing. Although this fibrosis likely originates as a protective mechanism, persistent inflammation may lead to dysregulated wound healing and, in turn, excessive deposition of the extracellular matrix and fibrosis. A better understanding of the mechanism of intestinal fibrosis will likely have a dramatic impact on the treatment of CD and its complications. Although fibroblasts are considered a heterogeneous population, those that express fibroblast-specific protein 1 (FSP1) or 1-smooth muscle actin (1SMA) have been most extensively studied in the context of fibrosis. One important source of activated fibroblasts in chronic diseases of organs including the kidney, liver and heart is a process termed Epithelial to Mesenchymal Transition (EMT). EMT defines a pathway in which epithelial cells lose their phenotypic and functional characteristics, while acquiring mesenchymal features such as a spindle shape and invasive capacity. EMT is mediated by transforming growth factor-2 (TGF2) and treatment with bone morphogenic protein-7 (BMP-7) inhibits inflammation, apoptosis and EMT by counteracting the pro-fibrotic actions of TGF2. The role of EMT in intestinal fibrosis has yet to be investigated. In Aim 1 we propose to use transgenic mice in which intestinal epithelial cells are lineage tagged to characterize activated fibroblasts originating from EMT in the setting of TNBS-induced Crohn's colitis. In Aim 2 we will first evaluate whether EMT occurs by a TGF2-induced Smad-dependent pathway in vitro and then address the role of TGF2 receptor signaling in vivo by inducing TNBS Crohn's colitis in mice that lack a functional TGF2RII in intestinal epithelial cells. We will also evaluate the role of Smad- mediated TGF2-signaling in TNBS Crohn's colitis by experimenting in mice that lack Smad4 in intestinal epithelial cells. In Aim 3 we will address the effect of BMP-7 treatment on EMT in vitro and intestinal fibrosis in TNBS Crohn's colitis. We will utilize the transgenics lacking Smad4 in intestinal epithelial cells to determine whether BMP-7 treatment exerts its actions purely through Smad-dependent inhibition of pro-fibrotic TGF2 signals or via alternate pathways. Finally, we will assess the synergistic properties of BMP-7 and anti-TNF1 therapy on intestinal fibrosis in TNBS Crohn's colitis. Collectively, our studies will offer new mechanistic insights into the emergence of intestinal fibrosis as well as novel targets for therapeutic interventions. PUBLIC HEALTH RELEVANCE: Intestinal fibrosis is a major and clinically significant complication of idiopathic inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC). While fibrosis is more commonly associated with CD, it is also sometimes seen in chronic UC. The mechanisms by which intestinal fibrosis occurs in the setting of IBD are incompletely understood and, in the absence of a defined mechanism, it is difficult to explore specific therapies to halt or reverse this process. Here, we propose to examine the underlying mechanism of fibrosis in the context of IBD by evaluating the contribution of Epithelial to Mesenchymal Transition (EMT) to intestinal fibrosis associated with a mouse model of CD. Using transgenic mouse models with specific molecular disruption of pathways involved in fibroblast proliferation/activation and EMT, we will attempt to understand the genetic and biochemical underpinnings of this process in intestinal fibrosis. We will also explore the potential therapeutic efficacy of Bone Morphogenic Protein-7 (BMP-7) as a means to boost this antifibrotic pathway.

描述（由申请人提供）：瘘管和纤维狭窄形式的肠纤维化是炎症性肠病，特别是克罗恩病（CD）的主要并发症。超过1/3的CD患者需要手术来缓解与纤维化狭窄相关的梗阻，许多患者因为疾病复发而需要重复干预。尽管一些药物可用于靶向CD的强烈炎症过程特征，但对肠纤维化的机制知之甚少，并且对于这种常见且极其病态的并发症没有特异性治疗。肠纤维化被认为遵循纤维发生的共同途径，如在其他器官中所见，其中活化的成纤维细胞被募集到炎症部位以用于伤口愈合。虽然这种纤维化可能起源于保护机制，但持续性炎症可能导致伤口愈合失调，进而导致细胞外基质过度沉积和纤维化。更好地了解肠纤维化的机制将可能对CD及其并发症的治疗产生巨大影响。虽然成纤维细胞被认为是一个异质群体，那些表达成纤维细胞特异性蛋白1（FSP 1）或1-平滑肌肌动蛋白（1 SMA）已被最广泛的研究在纤维化的背景下。肾脏、肝脏和心脏等器官慢性疾病中活化成纤维细胞的一个重要来源是一个称为上皮细胞向间充质转化（EMT）的过程。EMT定义了一种途径，其中上皮细胞失去其表型和功能特征，同时获得间充质特征，如纺锤形和侵入能力。EMT由转化生长因子-2（TGF 2）介导，并且用骨形态发生蛋白-7（BMP-7）治疗通过抵消TGF 2的促纤维化作用来抑制炎症、细胞凋亡和EMT。EMT在肠纤维化中的作用还有待研究。在目标1中，我们建议使用转基因小鼠，其中肠上皮细胞谱系标记，以表征激活的成纤维细胞来源于EMT在TNBS诱导的克罗恩氏结肠炎的设置。在目标2中，我们将首先评估EMT是否通过TGF 2诱导的Smad依赖性途径在体外发生，然后通过在肠上皮细胞中缺乏功能性TGF 2 RII的小鼠中诱导TNBS克罗恩氏结肠炎来解决TGF 2受体信号传导在体内的作用。我们还将通过在肠上皮细胞中缺乏Smad 4的小鼠中进行实验来评估Smad介导的TGF 2信号传导在TNBS克罗恩氏结肠炎中的作用。在目标3中，我们将阐述BMP-7治疗对TNBS克罗恩氏结肠炎中体外EMT和肠纤维化的影响。我们将利用肠上皮细胞中缺乏Smad 4的转基因来确定BMP-7治疗是否纯粹通过Smad依赖性抑制促纤维化TGF 2信号或通过替代途径发挥其作用。最后，我们将评估BMP-7和抗TNF-1治疗对TNBS克罗恩氏结肠炎肠纤维化的协同作用。总的来说，我们的研究将为肠道纤维化的出现提供新的机制见解，并为治疗干预提供新的靶点。 公共卫生相关性：肠纤维化是特发性炎症性肠病（IBD）的主要和临床上显著的并发症，IBD包括克罗恩病（CD）和溃疡性结肠炎（UC）。虽然纤维化更常见于CD，但有时也见于慢性UC。人们对IBD背景下肠道纤维化发生的机制还不完全了解，在缺乏明确机制的情况下，很难探索阻止或逆转这一过程的特定疗法。在这里，我们建议通过评估上皮间质转化（EMT）与CD小鼠模型相关的肠纤维化的贡献来研究IBD背景下纤维化的潜在机制。使用转基因小鼠模型与特定的分子干扰的途径参与成纤维细胞增殖/活化和EMT，我们将试图了解这一过程中肠纤维化的遗传和生化基础。我们还将探索骨形态发生蛋白-7（BMP-7）作为促进这种抗纤维化途径的一种手段的潜在治疗效果。