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: 8912450
• 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 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8912450
• 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.

描述（由申请人提供）：以瘘管和纤维狭窄性狭窄形式出现的肠道纤维化是炎症性肠病，尤其是克罗恩病（CD）的主要并发症。超过1/3的乳糜泻患者需要手术来缓解与纤维化狭窄相关的梗阻，许多患者由于疾病复发需要重复干预。尽管一些药物可用于针对乳糜泻的强烈炎症过程，但对肠道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特异性治疗方法。肠道纤维化被认为遵循一种常见的纤维形成途径，就像在其他器官中看到的那样，在这种途径中，被激活的成纤维细胞被招募到炎症部位，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。更好地了解肠纤维化的机制可能会对乳糜泻及其并发症的治疗产生重大影响。虽然成纤维细胞被认为是异质群体，但那些表达成纤维细胞特异性蛋白1 （FSP1）或1-平滑肌肌动蛋白（1SMA）的细胞在纤维化的背景下被广泛研究。在包括肾、肝和心脏在内的器官慢性疾病中，活化成纤维细胞的一个重要来源是一个被称为上皮到间充质转化（EMT）的过程。EMT定义了上皮细胞失去其表型和功能特征的途径，同时获得间充质特征，如纺锤形和侵袭能力。EMT是由转化生长因子-2 （TGF2）介导的，骨形态发生蛋白-7 （BMP-7）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尚未被研究。在目的1中，我们建议使用肠上皮细胞谱系标记的转基因小鼠来表征tnbs诱导的克罗恩结肠炎中源自EMT的活化成纤维细胞。在Aim 2中，我们将首先评估EMT是否通过TGF2诱导的smad依赖途径在体外发生，然后通过在肠上皮细胞中缺乏功能性TGF2RII的小鼠中诱导TNBS克罗恩结肠炎来解决TGF2受体信号在体内的作用。我们还将通过在肠上皮细胞缺乏Smad4的小鼠中进行实验，评估Smad介导的tgf2信号在TNBS克罗恩结肠炎中的作用。在Aim 3中，我们将探讨BMP-7治疗对体外EMT和TNBS克罗恩结肠炎肠道纤维化的影响。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依赖性抑制促纤维化TGF2信号或通过其他途径发挥其作用。最后，我们将评估BMP-7和抗tnf1治疗对TNBS克罗恩结肠炎肠道纤维化的协同作用。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。