Regulation of Mucosal Lymphocytes

项目总结/摘要 CEACAM1是一种单通道I型跨膜蛋白，是癌胚抗原的原始成员。 免疫球蛋白分子的CEA家族，其表达于免疫球蛋白的顶面和基底面。 肠上皮细胞（IEC）和广泛的免疫细胞类型。然而，其对肠道的功能 上皮细胞（IEC）是未知的。目前的研究建议解决了未回答的问题， CEACAM1是否用于将微生物或宿主信号从顶面和/或基底面转化为细胞外基质， 通过IEC产生抗菌肽（AMP）。IEC感知微生物存在的能力 并将抗菌肽（AMP）递送到管腔中代表了粘膜防御的主要机制。我们 长期的目标是确定CEACAM1介导的AMP刺激是否能保护细胞免于凋亡， 和病原微生物入侵IEC和结肠炎的易感性，为此所需的矢量方向 刺激（顶侧和/或基底侧），无论其是否特异性依赖于CEACAM1亚型， (S)如果CEACAM1的高亲和力配体可以被开发以刺激这些保护性的细胞质尾区， 活动本研究的目的是阐明CEACAM1如何刺激AMP的产生，以及是否 这些信息一起可以被用于治疗目的。我们的中心假设是CEACAM1 作为一种新型的微生物传感器，其响应于产生AMP的特定微生物或宿主配体 这对屏障保护很重要。这一基本原理来自最近的研究，即一个特定的缺陷， 小鼠IEC中的CEACAM1在体内导致IEC的AMP表达降低，与增加的易感性偶联 结肠炎和病原微生物的入侵。我们的中心假设将通过三个具体目标进行测试：1） 确定IEC相关CEACAM1是否调节AMP的产生和宿主对结肠炎的易感性 和肠道病原体; 2）确定特定的CEACAM1亚型是否负责递送活化的CEACAM1， 产生信号以诱导AMP，和; 3）定义增强人CEACAM1配体的治疗策略， 产生了这些保护性反应。在目标1中，我们将确定先天和/或适应性， 肠炎症的起源是由IEC中CEACAM1缺乏引起的， 涉及管腔中细菌移位的增加。目标2将决定是否 CEACAM1-S亚型可刺激IEC响应药理学和微生物信号产生AMP 以及这种刺激是否可以响应于CEACAM1在顶侧和基底侧表面上的连接而发生。 脸上在目标3中，我们寻求产生具有增强的刺激IEC产物的能力的人CEACAM1变体。 AMP在体外和体内的作用，并因此提供对实验性结肠炎的保护。总的来说，这一建议是 重要的是，它将CEACAM1定义为微生物传感器，识别新的微生物来源作为配体， CEACAM1和创建具有治疗潜力的高亲和力配体，共同具有重要意义 炎症性肠病和粘膜防御机制。

PROJECT SUMMARY/ABSTRACT CEACAM1 is a single-pass type I transmembrane protein and the primordial member of the carcinoembryonic antigen (CEA) family of immunoglobulin molecules that is expressed on the apical and basolateral surfaces of intestinal epithelial cells (IEC) and on a wide range of immune cell types. However, its functions on intestinal epithelial cells (IECs) are unknown. The current research proposal addresses the unanswered question of whether CEACAM1 acts to convert microbial or host signals from the apical and/or basolateral surface into the production of antimicrobial peptides (AMP) by IECs. The ability of the IEC to sense the presence of microbes and deliver antimicrobial peptides (AMP) into the lumen represents a major mechanism of mucosal defense. Our long-term goals are to determine whether CEACAM1-mediated stimulation of AMPs protects from commensal and pathogenic microbe invasion of the IEC and susceptibility to colitis, the vectoral direction required for this stimulation (apical and/or basolateral), whether it is specifically dependent upon CEACAM1 isoforms with a short (S) cytoplasmic tail and if high-affinity ligands for CEACAM1 can be developed to stimulate these protective activities. The objective of this research is to elucidate how CEACAM1 stimulates AMP production and whether this information together can be co-opted for therapeutic purposes. Our central hypothesis is that CEACAM1 functions as a novel microbial sensor that responds to specific microbes or host ligands with production of AMPs that are important to barrier protection. This rationale is derived from recent studies that a specific deficiency of CEACAM1 in mouse IEC in vivo leads to decreased AMP expression by IECs coupled to increased susceptibility to colitis and invasion by pathogenic microbes. Our central hypothesis will be tested with three specific aims: 1) Determine whether IEC-associated CEACAM1 regulates the production of AMP and host susceptibility to colitis and enteropathogens; 2) Determine whether specific CEACAM1 isoforms are responsible for delivering activat- ing signals to induce AMPs, and; 3) Define a therapeutic strategy to enhance human CEACAM1 ligands that interact homophilically to induce these protective responses. In Aim 1, we will determine the innate and/or adap- tive origins of the intestinal inflammation that ensues from CEACAM1-deficiency in the IEC and whether this involves increased bacterial translocation of founding populations in the lumen. Aim 2 will determine whether CEACAM1-S isoforms can stimulate IECs to produce AMPs in response to pharmacologic and microbial signals and whether such stimulation can occur in response to ligation of CEACAM1 on the apical and basolateral sur- faces. In Aim 3, we seek to generate human CEACAM1 variants with enhanced ability to stimulate IEC produc- tion of AMP in vitro and in vivo and as such provide protection from experimental colitis. Overall, this proposal is significant because it will define CEACAM1 as a microbial sensor, identify novel microbial sources as ligands for CEACAM1 and create high-affinity ligands with therapeutic potential that together have important implications for inflammatory bowel disease and mucosal defense mechanisms.