Eotaxin in Colitis and Colitis-Associated Carcinogenesis

描述(由申请人提供)： 炎症性肠病(IBD)由溃疡性结肠炎(UC)和克罗恩病组成，在100多万美国人中受到影响，会导致显著的发病率，并可发展为结肠癌。虽然已经确定了多种易感因素，但IBD的原因或触发因素仍不清楚。目前IBD的治疗方案是从一系列免疫抑制剂中选择的，这些药物可能会因多种副作用和费用而变得复杂。在寻找新的治疗方案，包括体外研究、小鼠模型研究和前瞻性收集的成人UC患者队列中，我们的人类血清图谱数据表明，Eoaxin-1可能是UC疾病活动的生物标记物。嗜酸性粒细胞趋化因子-1(CCL11)是嗜酸性粒细胞的趋化因子。在定义了40名对照组和137名UC患者的细胞因子和趋化因子谱后，与对照组相比，UC患者中有13种组织细胞因子和趋化因子显著升高，但在42个分析物中，只有3种在血清中升高：嗜酸性粒细胞趋化因子-1、G-CSF和GM-CSF。其中，嗜酸性粒细胞趋化蛋白-1是在所有疾病严重程度的血清和组织中唯一升高的分析物。嗜酸性粒细胞趋化因子-1的增加在儿童UC组织中已被显示，并与嗜酸性炎症有关，但以前还没有在大规模的成人UC队列中进行研究。由于这一观察的新颖性，研究嗜酸性粒细胞趋化蛋白-1在小鼠结肠炎和结肠炎相关癌变模型中的作用是这一建议的重点。随着血清和组织中嗜酸性粒细胞-1的升高，UC患者结肠组织中的嗜酸性粒细胞显著增加，并且嗜酸性粒细胞计数与组织中的嗜酸性粒细胞水平呈正相关。我的合作者已经证明，在葡聚糖硫酸钠(DSS)诱导的结肠炎中，嗜酸性粒细胞趋化蛋白-1被上调，现在我们首次证明了嗜酸性粒细胞趋化蛋白-1在以下方面上调： 它们包括：1)轮状柠檬酸杆菌诱导的结肠炎组织；2)T细胞转移诱导的结肠炎组织；3)偶氮甲烷(AOM)-DSS结肠炎相关癌变模型中诱发的肿瘤；4)轮状柠檬酸杆菌激活的巨噬细胞或结肠上皮细胞。然而，在幽门螺杆菌诱导的小鼠胃炎组织中，嗜酸性粒细胞趋化因子-1并没有增加，这表明这不是一个非 炎症的特定成分。假设：嗜酸性粒细胞趋化因子-1通过作用于巨噬细胞和上皮细胞，是结肠炎和结肠炎相关癌变的关键介质。本项目的具体目的是：1.确定嗜酸性粒细胞趋化因子-1在实验性结肠炎中的调控作用。我们将利用涉及免疫激活的轮状芽胞杆菌感染结肠炎模型和涉及免疫激活和上皮损伤的结肠炎T细胞转移模型。我们将在轮状幼虫模型中比较野生型(WT)和嗜酸性粒细胞趋化蛋白1-/-小鼠，以及在T细胞转移模型中过继转移和不过继转移CD4+CD45RBhi效应T细胞的情况下，比较嗜酸性粒细胞趋化因子1+/+Rag2-/-和嗜酸性粒细胞趋化因子1-/-Rag2-/-小鼠。在每种结肠炎模型中，将评估以下各项：临床参数、结肠和系统的天然免疫反应，重点是巨噬细胞的表型和功能，以及上皮功能。2.探讨嗜酸性粒细胞趋化因子-1在慢性结肠炎及结肠炎相关癌变过程中的作用。我们的初步数据首次显示，在AOM-DSS模型中，结肠炎相关肿瘤增加了eoaxin-1的水平。我们将利用WT和嗜酸性粒细胞趋化蛋白1-/-小鼠的AOM-DSS模型来确定是否通过修改eoaxin-1基因缺失引起的炎症反应可以降低CAC的风险。在慢性结肠炎(接受多周期DSS治疗的小鼠)和结肠炎相关肿瘤形成(接受AOM治疗的小鼠，然后进行多周期DSS治疗)中，将评估以下临床参数：包括肿瘤大小和多发性在内的临床参数、以巨噬细胞表型和功能为重点的结肠和全身固有免疫反应，以及包括肿瘤和邻近非肿瘤组织中的上皮功能。这些研究将为嗜酸性粒细胞趋化蛋白-1在IBD和相关癌症发生中的作用提供新的机制见解。

DESCRIPTION (provided by applicant): With more than one million Americans affected, inflammatory bowel disease (IBD), consisting of ulcerative colitis (UC) and Crohn's disease, causes significant morbidity and can progress to colon cancer. While multiple predisposing factors have been identified, the cause or trigger for IBD remains unknown. Current treatment regimens for IBD are selected from an assortment of immunosuppressive agents, which can be complicated by multiple side effects and expense. In the search for new therapeutic options, including studies in vitro, in mouse models, and in a prospectively collected cohort of adult patients with UC, our human serum profiling data indicate that eotaxin-1 may be a biomarker of disease activity in UC. Eotaxin-1 (CCL11) is a chemoattractant for eosinophils. When the cytokine and chemokine profiles in this cohort of 40 controls and 137 UC patients were defined, there were 13 tissue cytokines and chemokines that were significantly elevated in the UC versus control patients, but out of a panel of 42 analytes, there were only 3 that were elevated in the serum: eotaxin-1, G-CSF, and GM-CSF. Of these, eotaxin-1 was the only analyte increased in both serum and tissue at all levels of disease severity. Increased eotaxin-1 has been shown in pediatric UC tissues, and has been linked to eosinophilic inflammation, but has not been previously investigated in a large, prospective adult UC cohort. Due to the novelty of this observation, studies of the role of eotaxin-1 in mouse models of colitis and colitis-associated carcinogenesis are the focus of this proposal. Along with the increased serum and tissue eotaxin-1, there is a significant increase in colonic tissue eosinophils in UC patients versus controls, and eosinophil counts correlated with tissue eotaxin-1 levels. Eotaxin-1 has been shown to be increased in dextran sulfate sodium (DSS) induced colitis by my collaborator, and we now show for the first time that eotaxin-1 is upregulated in: 1) Citrobacter rodentium-induced colitis tissues; 2) T cell transfer-induced colitis tissues; 3) tumor induced in the azoxymethane (AOM)-DSS model of colitis-associated carcinogenesis; and 4) macrophages or colonic epithelial cells activated with C. rodentium. However, eotaxin-1 is not increased in mouse Helicobacter pylori-induced gastritis tissues, indicating that this is not a non specific component of inflammation. Hypothesis: Eotaxin-1 is a key mediator of colitis and colitis-associated carcinogenesis via effects on macrophages and epithelial cells. The Specific Aims for this project are: 1. To determine the role of eotaxin-1 in the modulation of experimental colitis. We will utilize the C. rodentium infection model of colitis that involves immune activatio and the T cell transfer model of colitis that involves immune activation and epithelial damage. We will compare wild-type (WT) and eotaxin1-/- mice in the C. rodentium model, as well as eotaxin1+/+Rag2-/- and eotaxin1-/-Rag2-/- mice, with and without adoptive transfer of CD4+CD45RBhi effector T cells in the T cell transfer model. In each model of colitis the following will be assessed: clinical parameters, the colonic and systemic innate immune response focusing on macrophage phenotype and function, as well as epithelial function. 2. To determine the role of eotaxin-1 in the modulation of chronic colitis and colitis-associated carcinogenesis (CAC). Our preliminary data shows for the first time that colitis-associated tumors in the AOM-DSS model have increased eotaxin-1 levels. We will utilize the AOM-DSS model in WT and eotaxin1-/- mice to establish whether modification of the inflammatory response caused by deletion of eotaxin-1 can decrease the risk for CAC. In both chronic colitis (mice treated with multiple cycles of DSS) and colitis-associated tumorigenesis (mice treated with AOM followed by multiple cycles of DSS) the following will be assessed: clinical parameters including tumor size and multiplicity, colonic and systemic innate immune responses focusing on macrophage phenotype and function, as well as epithelial function, including in tumor and adjacent non-tumor tissues. These studies will provide new mechanistic insights into the role of eotaxin-1 in IBD and associated carcinogenesis.