IL-2RG基因突变导致的X-SCID是致死性的、发病率最高的联合免疫缺陷病，表现为T淋巴细胞严重缺乏。目前虽然从遗传角度对其发病机制有一定认识，但仍缺乏从发育细胞生物学及分子网络的角度去探讨该疾病发生的深层次机制。申请人拟建立X-SCID患儿来源的诱导多能干细胞疾病模型，造血分化后与OP9-DL1共培养建立疾病模型iPS细胞的体外T细胞发育动力学模式，从而明确疾病发生的发育细胞生物学机制。在此基础上，运用生物信息学的分析方法比较不同T细胞分化阶段突变和野生型样本转录组数据，找出参与X-SCID的各种基因或信号通路，在分子网络水平进一步理解IL-2RG突变引起SCID的发病机理，为药物筛查提供潜在靶点。最后，利用基因组编辑技术在 iPS细胞中修复IL-2RG突变，定向分化为造血干细胞，将其注入免疫缺陷小鼠体内进行人免疫细胞重建，为iPS细胞应用于人SCID细胞移植治疗提供参考。

X-linked severe combined immunodeficiency (X-SCID) caused by mutations of the gene for IL2RG has the highest rate of combined immunodeficiency diseases. X-SCID is fatal, and patients are characterized by the absence of or markedly diminished T cells. So far, there are no reports understanding X-SCID mechanisms on developmental cell biology and molecular network levels. In this project, we will reprogram somatic cells from X-SCID patients into induced pluripotent stem cells (iPS cells) to set up X-SCID model. By co-culturing with OP9-DL1 for T cell differentiation, we can figure out the T cell developmental kinetics of X-SCID iPS cells in vitro to identify the disease mechanism on developmental cell biology level. Based on understanding mechanism on developmental cell biology level, we will collect X-SCID and wild type samples from different stages of T cell differentiation for microarray analysis. Then we will compare and analyze transcripts between mutation and wild type samples by bioinformatics methodology to find genes and signaling pathways involved in X-SCID pathogenesis. This study can deep our understanding about X-SCID mechanism on molecular network level and provide potential targets for drug screening. Finally, we will correct IL2RG mutation in X-SCID iPS cells using genome editing technique, and differentiate the corrected iPS cells into hematopoietic stem cells to be transferred into SCID mice for human immune reconstitution. The methods and experience obtained in this study will provide references for human SCID treatment using iPS cells.