Humanized Mouse Models of Severe Combined Immunodeficiency

严重联合免疫缺陷的人源化小鼠模型

• 批准号: 7707949
• 负责人: SUNG-YUN PAI
• 金额: $ 21.25万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-08 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7707949
• 关键词: Acquired Immunodeficiency Syndrome; Affect; Animal Model; Animals; Apoptosis; Blood; Bone Marrow; Bone Marrow Examination; Bone Marrow Transplantation; CD34 gene; CD7 gene; Cell Differentiation process; Childhood; Congenital Disorders; Defect; Development; Engraftment; Failure; Frequencies; Generations; Genes; Goals; Hematopoietic Stem Cell Transplantation; Hematopoietic stem cells; Hereditary Disease; Human; Immune; Immune response; Immune system; Immunodeficient Mouse; Interleukin 2 Receptor; Interleukin 2 Receptor Gamma; Intervention; Lead; Mature Thymocyte; Modeling; Molecular; Morbidity - disease rate; Mus; Mutation; Natural Killer Cells; Nature; Pathogenesis; Pathway interactions; Patients; Phenotype; Research; STAT5A gene; Sampling; Severe Combined Immunodeficiency; Signal Pathway; Signaling Molecule; Staging; System; T-Cell Development; T-Lymphocyte; Testing; Thymus Gland; Tissues; Toxic effect; Tumor stage; X-Linked Severe Combined Immunodeficiency; acquired immunodeficiency; base; cancer therapy; fetal; gene therapy; human disease; in vivo; knock-down; migration; mortality; mouse model; novel; progenitor; public health relevance; reconstitution; small hairpin RNA; therapy development; thymocyte

DESCRIPTION (provided by applicant): Severe combined immunodeficiency (SCID) is a heterogeneous group of fatal congenital disorders characterized by the absence of T lymphocytes. T cells develop from bone marrow derived T progenitors that migrate to the thymus and differentiate before export to the blood. The most common form, X-linked SCID, is caused by lack of common gamma chain (?c) expression. Because mouse models for X-linked SCID are lacking, we still know surprisingly little about why lack of ?c impairs T cell development. The goal of this project is to determine the stage(s) at which T cell development in the absence of ?c is aberrant, at the level of T progenitor generation, thymus seeding and/or intrathymic development. We hypothesize that T development will be affected at the T progenitor stage and more severely affected at an early stage of intrathymic development. We further hypothesize that failure of differentiation, rather than defects in proliferation/survival, causes an absolute block in development and that this failure can be rescued by reconstituting the specific components of the ?c signaling pathway. In Aim 1, we will examine the normal expression of ?c in human T cell progenitors and investigate whether T progenitors are present in the bone marrow of patients with X-linked SCID. In Aim 2 and Aim 3, we will create humanized mice bearing ?c deficient immune systems, using a new strain of NOD-scid immunodeficient mice that can support human T cell differentiation in vivo (NOD/scid Il2rgnull). In Aim 2 we will reconstitute NOD/scid Il2rgnull mice with normal human bone marrow in which ?c has been knocked down by lentiviral expression of short hairpin RNA. Using these "?c knockdown mice," we will analyze bone marrow and thymus, and characterize the precise nature of the T cell differentiation block. In Aim 3 we will reconstitute NOD/scid Il2rgnull mice with bone marrow from patients with X-linked SCID. We will then use this "humanized X-SCID" mouse model to test whether activation of the STAT5 pathway or Akt pathway can restore T cell development in the absence of ?c. Humanized mice will give us the ability to propagate normal and aberrant human immune systems in a tractable animal system and bridge the gap that currently exists between mouse models and human disease. We believe this model will also ultimately lead to discovery of novel genes critical for human immune development and novel therapies for SCID. PUBLIC HEALTH RELEVANCE: T cells are an essential component of the immune system. Congenital absence of T cells (severe combined immunodeficiency or SCID) or acquired immunodeficiency (such as in AIDS, following bone marrow transplantation or after cancer treatment) all cause significant morbidity and mortality. By studying why T cells fail to develop in the most common form of SCID, we hope to develop therapies that enhance T cell development and thus in turn enhance T cell dependent immune responses.

描述(由申请人提供)：严重联合免疫缺陷(SCID)是一组以T淋巴细胞缺失为特征的不同类型的致命性先天性疾病。T细胞来自骨髓来源的T祖细胞，它们迁移到胸腺并分化，然后输出到血液中。最常见的形式是X连锁SCID，是由于缺乏共同的伽马链(？C)表达引起的。由于缺乏X连锁SCID的小鼠模型，我们仍然对缺乏？C损害T细胞发育的原因知之甚少。本项目的目标是从T祖细胞的产生、胸腺播种和/或胸腺内发育的水平确定在缺乏βC的情况下T细胞发育异常的阶段(S)。我们假设T细胞发育将在T祖细胞阶段受到影响，在胸腺内发育的早期阶段受到更严重的影响。我们进一步假设，分化的失败，而不是增殖/存活的缺陷，导致了发育的绝对障碍，这种失败可以通过重组？C信号通路的特定成分来挽救。在目标1中，我们将检测人类T细胞祖细胞的正常表达，并调查X连锁SCID患者的骨髓中是否存在T祖细胞。在目标2和目标3中，我们将使用一种新的能在体内支持人类T细胞分化的NOD-SCID免疫缺陷小鼠品系(NOD/SCID Il2rgnull)，创建具有？C缺陷免疫系统的人源化小鼠。在目标2中，我们将用正常的人骨髓重建NOD/SCID Il2rgnull小鼠，其中？C已被慢病毒表达的短发夹状RNA击倒。利用这些“？C基因敲除小鼠”，我们将分析骨髓和胸腺，并确定T细胞分化障碍的确切性质。在目标3中，我们将用X连锁SCID患者的骨髓重建NOD/SCID小鼠。然后，我们将使用这种“人源化X-SCID”小鼠模型来测试在没有C的情况下，激活STAT5通路或Akt通路是否可以恢复T细胞的发育。人源化小鼠将使我们能够在一个易驯服的动物系统中繁殖正常和异常的人类免疫系统，并弥合目前存在的小鼠模型和人类疾病之间的差距。我们相信，这一模型最终还将导致发现对人类免疫发育至关重要的新基因，以及治疗SCID的新疗法。公共卫生相关性：T细胞是免疫系统的重要组成部分。先天性T细胞缺乏(严重联合免疫缺陷或SCID)或获得性免疫缺陷(如艾滋病、骨髓移植或癌症治疗后)都会导致显著的发病率和死亡率。通过研究为什么T细胞不能在最常见的SCID中发育，我们希望开发出促进T细胞发育的治疗方法，从而增强T细胞依赖的免疫反应。