Antioxidant regulation of intestinal homeostasis and disease

项目摘要 该提案详细说明了一项5年培训计划，以帮助Sarah Short博士的持续发展。成 独立GI研究员这项研究计划将集中在阐明谷胱甘肽过氧化物酶的作用1 （GPx 1），一种在炎症性肠病（IBD）中广泛表达的硒酶和有效的抗氧化剂 和结肠炎相关的发育不良（CAD）。使用Gpx 1-/-小鼠的令人信服的初步数据表明，与Gpx 1-/-小鼠不同， 许多抗氧化剂的损失加剧了小鼠结肠炎，GPx 1的损失赋予了对葡聚糖的惊人保护， 硫酸钠（DSS）诱导结肠炎。GPx 1缺陷也增加了3D类器官的存活率和干性 并改变组织培养细胞中的代谢，这可另外促进再生和伤口愈合。 GPx 1表达也改变免疫细胞功能，因为Gpx 1-/-骨髓来源的巨噬细胞具有 对“M2”刺激的反应增强，迁移能力下降。总之，这些结果表明GPx 1 通过上皮细胞和免疫细胞功能的改变增强炎性损伤。 基于这些发现，该提议的假设是GPx 1在炎症性肠中是有害的 干细胞功能、氧化还原稳态和免疫反应的改变导致疾病。此外，抑制GPx 1 活性可能是一种有效的治疗策略。这一假设将在两个特定的目标进行测试，以确定 GPx 1如何促进肠上皮细胞稳态、氧化应激、结肠炎和结肠炎相关 发育不良第一个目标将研究上皮功能，利用肖特博士10多年的经验， 上皮细胞生物学和屏障功能。第二个目标将补充上皮为基础的研究， 确定GPx 1缺失如何改变免疫细胞的募集、分化和功能，并确定这些变化是如何发生的。 改变改变肠损伤反应。除了作为逻辑上的“下一步”实验， GPx 1功能，这些实验提供了完美的框架，以进一步博士短的发展方面 粘膜免疫学，这有助于肠道疾病，并将包括新的培训，在流式细胞术， 趋化因子分析、骨髓移植和T细胞转移结肠炎模型。肖特博士的职业生涯 通过与主要导师克里斯托弗威廉姆斯博士定期讨论，将进一步加强发展， 她的指导委员会由基思威尔逊博士、杰里米戈特尔和肖恩戴维斯组成。所有研究和 培训将在范德比尔特和该机构的医学系和胃肠病学系进行 非常支持肖特博士的学术生涯，并全力支持她的申请。 肖特博士的最终目标是成为一名独立的学术研究人员，专注于 调节IBD和结肠炎相关癌症的发展和严重程度， 这些患者的选择。有趣的是，本申请中提出的两个具体目标都将GPx 1评估为 使用硫普罗宁的治疗靶点，这是FDA批准的，耐受性良好。这些培训， 经验将确保肖特博士准备在IBD指导一个全面的独立研究计划。

Project Summary This proposal details a 5-year training plan to aid the continued develop of Dr. Sarah Short, Ph.D. into an independent GI researcher. This research plan will focus on elucidating the role of glutathione peroxidase 1 (GPx1), a ubiquitously expressed selenoenzyme and potent antioxidant, in inflammatory bowel disease (IBD) and colitis-associated dysplasia (CAD). Compelling preliminary data using Gpx1-/- mice indicates that unlike many antioxidants whose loss exacerbates murine colitis, loss of GPx1 confers striking protection from dextran- sodium sulfate (DSS)-induced colitis. GPx1 deficiency also increases survival and stemness in 3D organoids and alters metabolism in tissue culture cells, which may additionally promote regeneration and wound healing. GPx1 expression also modifies immune cell function, as Gpx1-/- bone marrow-derived macrophages have heightened response to “M2” stimuli and decreased migratory ability. Together, these results suggest that GPx1 augments inflammatory injury through alterations in both epithelial and immune cell function. Based on these finding, the hypothesis of this proposal is that GPx1 is detrimental in inflammatory bowel disease by altering stem cell function, redox homeostasis, and immune responses. Further, inhibiting GPx1 activity may be an effective therapeutic strategy. This hypothesis will be tested in two specific aims to determine how GPx1 contributes to intestinal epithelial cell homeostasis, oxidative stress, colitis, and colitis-associated dysplasia. The first aim will investigate epithelial function, capitalizing on Dr. Short’s over 10 years of experience in epithelial cell biology and barrier function. The second aim will complement epithelial-based studies by determining how GPx1 loss alters immune cell recruitment, differentiation, and function, and identify how these changes modify intestinal injury responses. In addition to being the logical “next step” experiments in defining GPx1 function, these experiments provide the perfect framework to further Dr. Short’s development in aspects of mucosal immunology which contribute to intestinal diseases, and will include new training in flow cytometry, chemokine analysis, bone marrow transplantation, and the T-cell transfer colitis model. Dr. Short’s career development will be further enhanced by regular discussions with primary mentor, Dr. Christopher Williams, and her mentoring committee consisting of Drs. Keith Wilson, Jeremy Goettel, and Sean Davies. All studies and training will take place at Vanderbilt, and the institution, Department of Medicine, and Gastroenterology Division are highly supportive of Dr. Short’s academic career and fully support her application. Dr. Short’s ultimate goal is to become an independent academic researcher focusing on mechanisms which regulate development and severity of IBD and colitis-associated cancer that can lead to improved therapeutic options for these patients. Interestingly, both specific aims proposed in this application will evaluate GPx1 as a therapeutic target using tiopronin, which is FDA-approved and well-tolerated. Together, these training experiences will ensure Dr. Short is poised to direct a well-rounded independent research program in IBD.