Regulation of Mucosal Lymphocytes

项目摘要/摘要 CEACAM1是一种单传的I型跨膜蛋白，是癌胚胎的原始成员 抗原(CEA)家族的免疫球蛋白分子，表达在顶端和基底外侧表面 肠上皮细胞(IEC)和多种免疫细胞类型。然而，其对肠道的作用 上皮细胞(IECs)是未知的。目前的研究提案解决了尚未回答的问题： CEACAM1是否起作用将微生物或宿主信号从根尖和/或基底外侧表面转化为 IECS生产抗菌肽(AMP)IEC感知微生物存在的能力 而将抗菌肽(AMP)输送到管腔是粘膜防御的主要机制。我们的 长期目标是确定CEACAM1介导的AMP刺激是否保护共生 以及病原微生物入侵IEC和对结肠炎的易感性，这是需要的矢量方向 刺激(心尖和/或基底外侧)，它是否特异性地依赖于CEACAM1亚型 (S)胞质尾部和IF高亲和力的CEACAM1配体可以刺激这些保护性的 活动。本研究的目的是阐明CEACAM1是如何刺激AMP产生的，以及 这些信息可以共同用于治疗目的。我们的中心假设是CEACAM1 作为一种新型的微生物传感器，对产生AMPs的特定微生物或宿主配体做出反应 这对屏障保护很重要。这一理论基础来自于最近的研究，即 小鼠IEC体内的CEACAM1可通过IECS降低AMP的表达并增加其易感性 对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验证：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亚型是否负责传递激活- ING信号，以诱导AMP；以及；3)定义一种治疗策略，以增强人CEACAM1配体， 通过同质性的相互作用来诱导这些保护性反应。在目标1中，我们将确定先天和/或后天- IEC中CEACAM1缺乏继发的肠炎症的可能起源以及这是否 包括腔内创始种群细菌移位的增加。目标2将决定是否 CEACAM1-S亚型可以刺激内皮细胞产生AMP，以响应药物和微生物信号 以及在根尖和基底外侧结扎CEACAM1是否会产生这种刺激。 面孔。在目标3中，我们试图产生具有增强刺激IEC产生的能力的人CEACAM1变体- AMP在体外和体内的作用，从而提供对实验性结肠炎的保护作用。总的来说，这项提议是 意义重大，因为它将CEACAM1定义为微生物传感器，识别新的微生物来源作为配体 CEACAM1和创造具有治疗潜力的高亲和力配体，这些都具有重要的意义 用于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.