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: 8261681
• 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/8261681
• 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; public health relevance; 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阻塞，并且许多患者由于疾病复发而需要重复干预。尽管一些药物可用于治疗克罗恩病的强烈炎症过程特征，但人们对肠纤维化的机制知之甚少，并且没有针对这种常见且极其病态的并发症的具体疗法。肠道纤维化被认为遵循纤维形成的共同途径，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达到伤口愈合的目的。尽管这种纤维化可能起源于一种保护机制，但持续的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。更好地了解肠道纤维化的机制可能会对克罗恩病及其并发症的治疗产生巨大影响。尽管成纤维细胞被认为是异质群体，但表达成纤维细胞特异性蛋白 1 (FSP1) 或 1-平滑肌肌动蛋白 (1SMA) 的成纤维细胞在纤维化背景下得到了最广泛的研究。包括肾脏、肝脏和心脏在内的慢性器官疾病中活化的成纤维细胞的一个重要来源是称为上皮间质转化（EMT）的过程。 EMT 定义了一条途径，在该途径中上皮细胞失去其表型和功能特征，同时获得间质特征，如纺锤体形状和侵袭能力。 EMT 由转化生长因子 2 (TGF2) 介导，骨形态发生蛋白 7 (BMP-7) 治疗可通过抵消 TGF2 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仍有待研究。在目标 1 中，我们建议使用转基因小鼠，其中肠上皮细胞被谱系标记，以表征 TNBS 诱导的克罗恩结肠炎中源自 EMT 的活化成纤维细胞。在目标 2 中，我们将首先在体外评估 EMT 是否通过 TGF2 诱导的 Smad 依赖性途径发生，然后通过在肠上皮细胞中缺乏功能性 TGF2RII 的小鼠中诱导 TNBS 克罗恩氏结肠炎来研究体内 TGF2 受体信号传导的作用。我们还将通过在肠上皮细胞中缺乏 Smad4 的小鼠中进行实验来评估 Smad 介导的 TGF2 信号在 TNBS 克罗恩结肠炎中的作用。在目标 3 中，我们将探讨 BMP-7 治疗对体外 EMT 和 TNBS 克罗恩结肠炎肠纤维化的影响。我们将利用肠上皮细胞中缺乏 Smad4 的转基因来确定 BMP-7 治疗是否纯粹通过 Smad 依赖性促纤维化 TGF2 信号抑制或通过替代途径发挥其作用。最后，我们将评估 BMP-7 和抗 TNF1 疗法对 TNBS 克罗恩结肠炎肠纤维化的协同作用。总的来说，我们的研究将为肠纤维化的出现提供新的机制见解，并为治疗干预提供新的目标。 公众健康相关性：肠道纤维化是特发性炎症性肠病 (IBD) 的主要且具有临床意义的并发症，其中包括克罗恩病 (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。 IBD 中肠道纤维化发生的机制尚不完全清楚，并且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具体疗法。在这里，我们建议通过评估上皮间质转化（EMT）对与 CD 小鼠模型相关的肠道纤维化的贡献来检查 IBD 背景下纤维化的潜在机制。使用对成纤维细胞增殖/激活和 EMT 相关途径进行特定分子破坏的转基因小鼠模型，我们将尝试了解肠道纤维化这一过程的遗传和生化基础。我们还将探索骨形态发生蛋白 7 (BMP-7) 的潜在治疗功效，作为增强这一抗纤维化途径的手段。