Generation and characterization of a humanized mouse model of Crohn's disease

克罗恩病人源化小鼠模型的建立和鉴定 克罗恩病（CD）和溃疡性结肠炎（UC）是炎症性肠病的两种主要形式 (IBD)这是一种慢性炎症性疾病，影响着大约300万美国人。发病机理 CD的发病率对每个患者来说都是不同的，涉及遗传因素、免疫系统和免疫系统之间的复杂相互作用。 系统，肠道微生物群和其他环境因素。IBD的小鼠模型在以下方面是非常宝贵的： 为复杂的发病机制提供了重要的机制见解，并指出了新的潜力 治疗目标然而，要把我们对人类的理解的进步转化为 IBD发病机制的新疗法，证明在临床上成功。一个主要的障碍是老鼠和 人类尽管有相似之处，但在肠道生理学方面有根本的差异，关键的是， 免疫系统的功能。第二个问题是绝大多数IBD小鼠模型 概括了UC的自然史，但没有CD的独特病理学。毫不奇怪， 在CD患者中失败的临床试验的显著例子最初是由结肠炎小鼠模型指导的 在临床前水平。临床前试验的一个诱人途径是人源化小鼠建模， 将人造血干细胞（HSC）移植到免疫缺陷小鼠中， 系统在鼠标主机上开发。人源化小鼠模型允许研究人类的功能。 免疫细胞，而不直接涉及人类患者。尽管最近在人类化方面取得了进展， 由于小鼠免疫系统的缺陷，IBD的人源化模型的开发滞后， 仅限于转移人CD 4 + T细胞后化学诱导结肠炎。翻译动物 一直缺乏忠实地概括人类CD病理学的模型。在这个项目中，我们的目标是开发 第一个CD的人源化小鼠模型。为此，我们将整合两个国家的最先进的鼠标 模型：一种遗传小鼠模型，特别类似于 人CD和MISTRG 6人源化模型，MISTRG 6人源化模型支持最全面的人源化， 迄今为止实现的免疫系统，不仅包括T、B和NK细胞，而且还包括骨髓细胞群 在CD中至关重要，如巨噬细胞和中性粒细胞。该试点项目的主要目标是：1）产生 通过CRISPR/Cas9工程改造这些小鼠并优化其免疫系统的人源化，以及2） 确定人源化克罗恩病发病机制的动力学并彻底表征其表型 在组织病理学和肠道免疫反应水平方面。这个人性化的系统将是一个 这是CD研究界重要且独特的临床前/转化工具。它将揭示 利用人类免疫细胞来驱动CD发病机制，也使未来的研究能够评估 候选疗法对人类靶点的有效性以及旨在揭示 与CD相关的人类遗传变异体对人类免疫系统功能的特异性影响。

Generation and characterization of a humanized mouse model of Crohn’s disease Crohn’s-disease (CD) and ulcerative colitis (UC) are the two major forms of inflammatory bowel disease (IBD), a chronic inflammatory disorder that affects an estimated 3 million Americans. The etiopathogenesis of CD is distinctive for each patient and involves a complex interaction between genetic factors, the immune system, the gut microbiota and other environmental factors. Mouse models of IBD have been invaluable in providing critical mechanistic insights into its complex etiopathogenesis and in indicating new potential therapeutic targets. However, it has been particularly difficult to translate advances in our understanding of IBD pathogenesis into novel therapies that prove successful in the clinic. A major obstacle is that mice and humans, despite their similarities, have fundamental differences in their intestinal physiology and, crucially, in the function of their immune system. A second problem is that the vast majority of mouse models of IBD recapitulate aspects of the natural history of UC but not the unique pathology of CD. Not surprisingly, notable examples of clinical trials that failed in CD patients were originally guided by mouse models of colitis at the preclinical level. One inviting avenue for pre-clinical testing is humanized mouse modeling, where human hematopoietic stem cells (HSCs) are engrafted into immunodeficient mice and a human immune system develops in the mouse host. Humanized mouse models allow to study the function of human immune cells in vivo without directly involving human patients. Despite recent progress in the humanization of the immune system in mice, the development of humanized models of IBD is lagging behind and has been limited to the chemical induction of colitis upon transfer of human CD4+ T-cells. Translational animal models that faithfully recapitulate human CD pathology have been lacking. In this project we aim to develop the first humanized mouse model of CD. For this purpose we will integrate two state-of-the-art mouse models: a genetic mouse model that specifically resembles the pathological and mechanistic features of human CD and the MISTRG6 humanized model which supports the most comprehensive humanization of the immune system achieved to date, including not only T, B and NK cells, but also myeloid populations crucial in CD such as macrophages and neutrophils. Major goals of this pilot project are to 1) generate these mice by CRISPR/Cas9 engineering and optimize the humanization of their immune system and 2) determine the kinetics of humanized Crohn’s pathogenesis and thoroughly characterize its phenotypic aspects at the level of tissue pathology and intestinal immune responses. This humanized system will be an important and unique preclinical/translational tool for the CD research community. It will reveal pathways employed by human immune cells to drive CD pathogenesis and also enable future studies assessing the effectiveness of candidate therapeutics against human targets as well as studies aiming to uncover the specific effect of human genetic variants associated with CD on the function of a human immune system.