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)，一种慢性炎症性疾病，估计影响300万美国人。病因病机 CD对每个患者都是独特的，涉及到遗传因素、免疫系统和免疫系统之间复杂的相互作用 系统、肠道微生物区系等环境因素。IBD的小鼠模型在 为其复杂的发病机制提供关键的机制洞察力，并表明新的潜力 治疗靶点。然而，将我们在理解方面的进展转化为 IBD发病机制转化为新的治疗方法，在临床上被证明是成功的。一个主要的障碍是老鼠和 尽管人类有相似之处，但他们在肠道生理上有根本的不同，而且至关重要的是， 它们的免疫系统的功能。第二个问题是绝大多数IBD的小鼠模型 概述UC的自然历史，但不是CD的独特病理。不足为奇的是， CD患者临床试验失败的显著例子最初是由小鼠结肠炎模型指导的 在临床前水平。临床前试验的一个诱人的途径是人性化的小鼠建模，其中 将人造血干细胞(HSCs)植入免疫缺陷小鼠和人类免疫缺陷小鼠体内 系统在鼠标主机上开发。人性化的小鼠模型可以研究人类的功能 体内的免疫细胞不直接涉及人类患者。尽管最近在人性化方面取得了进展 在小鼠免疫系统方面，人源化IBD模型的发展滞后，并已 仅限于在转移人类CD4+T细胞时化学诱导的结肠炎。翻译动物 一直缺乏能够真实再现人类CD病理的模型。在这个项目中，我们的目标是开发 CD的第一个人性化小鼠模型。为此，我们将集成两个最先进的鼠标 模型：一种遗传的小鼠模型，其病理和机制特征与 人类CD和支持最全面的人性化的MISTRG6人性化模型 到目前为止，免疫系统不仅包括T、B和NK细胞，而且还包括髓系细胞 对CD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)生成 这些小鼠通过CRISPR/Cas9工程并优化其免疫系统的人源化2) 确定人源化克罗恩病的发病动力学并对其表型进行深入研究 在组织病理和肠道免疫反应的水平上。这个人性化的系统将是一个 CD研究界重要而独特的临床前/翻译工具。它将揭示路径 被人类免疫细胞用来驱动CD的发病机制，并使未来的研究能够评估 针对人类靶点的候选疗法的有效性以及旨在揭示 与镉相关的人类基因变异对人类免疫系统功能的特殊影响。

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.