Regulatory role for an epithelial repair protein, LINGO2, in colitis

项目总结 炎症性肠病(Ibd)由一系列无法治愈、复发和缓解性疾病驱动。 肠粘膜屏障功能缺陷和异常的促炎反应 微生物区系。IBD患者患结肠炎相关性结肠癌(CAC)的风险增加，但 上皮细胞控制它的特定机制还不完全清楚。同样不清楚的是基因 预测哪些IBD患者可能进展为CAC的因素。这项建议的研究重点是 揭示一种新的上皮修复蛋白，富含亮氨酸的重复序列和含有Ig结构域的异常调节， Nogo受体相互作用蛋白家族2(LINGO2)参与恶性转化。在预赛中 数据显示，上皮细胞中Lingo2缺乏导致EGFR磷酸化上调， 与野生型相比，IL6处理后STAT3激活时间延长，细胞增殖增加 细胞。此外，Lingo2基因缺陷小鼠有严重的葡聚糖硫酸钠(DSS)诱导的结肠炎，即 被EGFR抑制所挽救。我们证明了Lingo2在免疫细胞中表达，并在 造血室有助于结肠炎的易感性。与已发表的观察结果一致 增加的EGFR信号是促肿瘤发生的，我们表明，当暴露在偶氮甲烷(AOM)和 DSS、Lingo2基因缺陷小鼠较对照小鼠更易发生CAC。我 因此，假设Lingo2通过调节EGFR和 STAT3活动。目的是首先机械地剖析Lingo2在上皮细胞中的细胞自主作用。 保护细胞免受CAC的影响，进而了解Lingo2缺乏是否在微环境中 对CAC很重要。我的假设将通过两个相互关联的具体目标来检验，这两个目标将检验 LINGO2和EGFR信号在CAC上皮细胞中的相互作用(Aim 1)，然后评估Lingo2是如何 缺乏影响CAC中STAT3激活细胞因子的产生和髓系细胞的活性(目标2)。 拟议中的实验将使用各种创新方法，包括使用独特的敲击小鼠 模型、三维器官培养模型系统和器官原位移植。拟议的研究是 意义重大，因为它将提供关于一种新的肿瘤抑制分子途径的新信息。 宾夕法尼亚大学提供了完美的研究环境来进行这项调查，因为当地 在粘膜生物学、上皮生物学和免疫学等相互关联的领域具有专业知识。候选人将会 获得小鼠和体外疾病建模的基本技能，并拓宽她的免疫学和上皮细胞 生物知识库。这些技能将极大地促进应聘者的职业发展 NIH资助的独立终身教职教员，长期目标是了解 控制粘膜修复和动态平衡的机制。

PROJECT SUMMARY Inflammatory bowel disease (IBD) constitutes a spectrum of incurable, relapsing and remitting disorders driven by intestinal mucosal barrier function defects and aberrant pro-inflammatory responses directed against microbial flora. IBD patients are at increased risk of developing colitis-associated colorectal cancer (CAC) but the epithelial specific mechanisms that control it are incompletely understood. Also unclear are the genetic factors that predict which IBD patients are likely to progress to CAC. The research focus of this proposal is to uncover how dysregulation of a novel epithelial repair protein, Leucine rich repeat and Ig domain-containing, nogo receptor-interacting protein family 2 (LINGO2) contributes to malignant transformation. In preliminary data, we show that Lingo2 deficiency in epithelial cells results in up-regulation of EGFR phosphorylation, prolonged STAT3 activation in response to IL6 treatment and increased proliferation compared to wildtype cells. Furthermore, Lingo2 deficient mice have severe dextran sodium sulfate (DSS) induced colitis that is rescued by EGFR inhibition. We demonstrate that Lingo2 is expressed in immune cells and its loss in the hematopoietic compartment contributes to susceptibility to colitis. Consistent with the published observations that increased EGFR signaling is pro-tumorigenic, we show that when exposed to azoxymethane (AOM) and DSS, Lingo2 deficient mice are more susceptible to the development of CAC compared to control mice. I therefore hypothesize that Lingo2 protects against the development of CAC through regulation of EGFR and STAT3 activity. The objective is to first mechanistically dissect the cell autonomous role of Lingo2 in epithelial cells in protection from CAC and then to understand whether Lingo2 deficiency in the microenvironment is important for CAC. My hypothesis will be tested through two inter-related Specific Aims that will examine the interplay of LINGO2 and EGFR signaling in epithelial cells in CAC (Aim 1) and then evaluate how Lingo2 deficiency affects the production of STAT3 activating cytokines and activity of myeloid cells in CAC (Aim 2). The experiments proposed will use various innovative approaches including the use of unique knock-in murine models, 3D organoid culture model systems and organoid orthotopic transplantation. The proposed research is significant because it will provide new information about a novel tumor suppressive molecular pathway. University of Pennsylvania provides the perfect research environment to conduct this investigation given local expertise in the inter-related fields of mucosal biology, epithelial biology and immunology. The candidate will gain fundamental skills in murine and in vitro disease modeling and broaden her immunology and epithelial biology knowledge base. These skill sets will greatly enhance the candidate's career development into an independent NIH funded tenure-track faculty member with the long term goal of understanding the mechanisms that control mucosal repair and homeostasis.