Lysyl oxidase mediated fibrosis in eosinophilic esophagitis

 描述(由申请者提供)：K08申请中建议的培训概述了指导研究和职业发展活动的综合计划，以及这位儿科胃肠病专家作为内科科学家追求独立研究职业生涯的具体战略。这个奖项将允许她在她的导师Rustgi博士和Nakagawa博士的指导下改进现有的技能并获得额外的技能。她将继续在职业发展、生物伦理学、拨款撰写和实验室管理方面的正式课程和研讨会。嗜酸性食管炎(EoE)是一种以食道嗜酸粒细胞浸润为特征的过敏性疾病。食道纤维化是EoE最严重的并发症，可导致吞咽困难、食物块嵌塞和食道狭窄。纤维化的定义是胶原过度沉积，导致组织僵硬。然而，胶原蛋白的质量，即胶原蛋白的交联度，可能与胶原蛋白的量一样重要。通过赖氨酰氧化酶(LOX)酶交联胶原蛋白可以增强组织内的硬度。组织硬度的增加可能支持增加纤维化的正反馈循环，因为已知成纤维细胞与僵硬的基质接触时会转分化为激活的肌成纤维细胞。初步数据表明，食道上皮细胞和食道成纤维细胞之间的相互作用，特别是通过细胞因子TNFa，增强了LOX的表达。此外，活动性EoE患者活检标本中LOX表达上调。基于这些发现，总体假设是LOX是EoE纤维化的关键调节因子，其功能特性部分通过特定的上皮-成纤维细胞相互作用来调节。使用已建立的器官类型培养模型系统，研究人员将确定上皮源性LOX如何增强肌成纤维细胞的活性和增加组织硬度(目标1)。她将利用遗传和化学抑制来确定TNFa诱导LOX表达的机制。她将进一步深入研究TNFa的信号通路，并确定最终导致LOX表达的信号机制(目标2)。最后，我们将在体内观察LOX在慢性EoE小鼠模型中的作用。通过化学抑制，她将确定LOX抑制对成纤维细胞激活和功能的影响(目标3)。她预计，这些研究的结果将确定LOX在EoE纤维化中的作用，并将提供 为未来在EOE管理和治疗中的翻译应用研究奠定基础。这些研究将阐明脂氧合酶在EoE中的新机制，并有可能对理解纤维化做出重大贡献。

 DESCRIPTION (provided by applicant): The proposed training in the K08 application outlines an integrated plan of mentored research and career development activities as well as a specific strategy for this pediatric gastroenterologist to pursue an independent research career as a physician scientist. This award will allow her to refine existing and gain additional skills with te guidance of her mentors Drs. Rustgi and Nakagawa. She will pursue formal coursework as well as seminars in career development, bioethics, grant writing, and laboratory management. Eosinophilic esophagitis (EoE) is an allergic disease characterized by esophageal infiltration of eosinophils. Esophageal fibrosis is the most serious complication of EoE, leading to dysphagia, food bolus impaction, and esophageal stricture. Fibrosis is defined as excess deposition of collagen leading to tissue stiffness. However, the quality of the collagen, meaning the extent of collagen cross-linking, may be just as important as the amount of collagen. Collagen cross-linking by the enzyme lysyl oxidase (LOX) enhances stiffness within the tissue. Increased tissue stiffness may support a positive feedback loop that increases fibrosis, since fibroblasts are known to transdifferentiate into activated myofibroblasts upon contact with a stiff matrix. Preliminary data suggest that cross-talk between esophageal epithelial cells and esophageal fibroblasts, specifically through the cytokine TNFa, enhances expression of LOX. In addition, LOX expression is upregulated in patients with active EoE in biopsy samples. Based on these findings, the overall hypothesis is that LOX is a critical modulator of fibrosis in EoE and that it functional properties are mediated in part through specific epithelial-fibroblast interactions. Using an established organotypic culture model system, the investigator will define how epithelial derived LOX enhances myofibroblast activation and increases tissue stiffness (Aim 1). She will determine the mechanism in which TNFa induces LOX expression utilizing genetic and chemical inhibition. She will further delve into the signaling pathway of TNFa and determine the mechanism of signaling that ultimately results in LOX expression (Aim 2). Lastly, we will look in vivo at the role of LOX in a chronic mouse model of EoE. Through chemical inhibition, she will determine the effect of LOX inhibition on fibroblast activation and function (Aim 3). She anticipates that results from these studies will define LOX's role in EoE fibrosis and will provide the foundation for future studies with translational applications in the management and therapy of EoE. These studies will elucidate novel mechanisms of LOX in EoE and have the potential to contribute significantly to understanding of fibrosis.