Inherited Disorders of Lymphocyte Development

描述(由申请人提供)：对人类严重联合免疫缺陷(SCID)的分子基础的研究开启了一个改进诊断和治疗这些罕见但严重的遗传性疾病的新时代，也为免疫学和淋巴细胞发育领域做出了贡献。虽然人类SCID的许多致病基因现已为人所知，但对“漏洞型”或“部分”SCID，也称为联合免疫缺陷(CID)的了解较少；SCID和未知基因的CID病例都提供了进一步发现的机会。此外，小鼠提供了解剖淋巴发育途径的能力，我们发现了一种新形式的小鼠SCID，缺乏一种预测的转录因子Zbtb1。缺乏Zbtb1的小鼠没有T细胞，但B系的发育只受到轻微的损害。这种T-B+SCID模型很重要，因为它的表型类似于在公共g链(GC)受体、IL-7受体a链(IL7Ra)和Janus kinase3(JAK3)中存在细胞因子信号通路缺陷的人类，而缺乏这些蛋白的小鼠与人类不同，它们拥有T细胞，但缺乏B细胞(T-B+)。我们将结合人类、患者和小鼠模型的资源，解决淋巴细胞发育和功能缺陷的发病机制。来自SCID/CID患者的样本将被评估已知的SCID基因的缺陷，而剩下的没有基因分配的病例将研究新的候选基因的缺陷。同时，我们将确定Zbtb1基因缺陷小鼠特定的发育和功能淋巴表型，以揭示Zbtb1在小鼠T和NK细胞发育以及B细胞分化和功能中的正常作用。比较Zbtb1小鼠、细胞因子信号转导缺陷患者和正常人类造血干细胞(HSC)中ZBTB1基因表达被RNAi抑制的情况，将为淋巴发育提供新的见解。因此，这项建议的目标是：(I)收集SCID和没有已知基因缺陷的CID患者的样本；(Ii)探索Zbtb1-小鼠B细胞损伤的SCID发病机制；(Iii)采用平行的体外和体内策略比较野生型与Zbtb1基因敲除小鼠以及正常与ZBTB1基因敲除小鼠的HSC的淋巴发育潜力；以及(Iv)寻找Zbtb1相互作用的伙伴和基因靶点，这些合作伙伴和基因靶点将与Zbtb1本身一起被评估是否有可能导致人类SCID的突变。 与公共卫生相关：从造血干细胞发育淋巴细胞尚不完全清楚，但对于治疗患有严重联合免疫缺陷(SCID)的人类、其他免疫和血液疾病以及癌症至关重要。我们研究患有SCID的人和小鼠，以找出他们潜在的基因缺陷，并了解淋巴细胞成熟所必需的途径。我们发现，尽管存在B淋巴细胞，但缺乏Zbtb1(一种以前未被研究的锌指蛋白)的小鼠不能形成T淋巴细胞。Zbtb1与抑制其靶基因表达的转录因子有关。我们将研究Zbtb1及其靶点如何在发育中的小鼠和人类淋巴样细胞中发挥作用，并确定Zbtb1或其作用基因的缺陷是否会导致人类免疫紊乱。

DESCRIPTION (provided by applicant): Studies of the molecular basis of human severe combined immunodeficiency (SCID) have ushered in a new era of improved diagnosis and treatment of these rare, but serious genetic disorders and also contributed to the fields of immunology and lymphocyte development. While many disease genes for human SCID are now known, less is known about "leaky" or "partial" SCID, also called combined immunodeficiency (CID); both SCID and CID cases of unknown genotype provide opportunities for further discovery. In addition, the mouse offers the power to dissect lymphoid developmental pathways, and we have discovered a new form of mouse SCID, deficiency of a predicted transcription factor Zbtb1. Mice lacking Zbtb1 have no T cells, but B lineage development is only mildly impaired. This T-B+ SCID model is important because its phenotype resembles that of humans with cytokine signaling pathway defects in the common g chain (gc) receptor, the IL-7 receptor a chain (IL7Ra), and Janus kinase 3 (Jak3), whereas the mouse knockouts lacking these proteins differ from humans in having T cells, but lacking B cells (T-B+). We will combine resources from human patients and mouse models to address the pathogenesis of lymphocyte developmental and functional defects. Samples from patients with SCID/CID will be assessed for defects in known SCID genes, and the cases remaining without a genotype assignment will be studied for defects in new gene candidates. Meanwhile, we will define the specific developmental and functional lymphoid phenotype of Zbtb1 deficient mice to uncover the normal role of Zbtb1 in mouse T and NK cell development and B cell differentiation and function. Comparisons between the Zbtb1- mouse, humans with cytokine signaling defects, and normal human hematopoietic stem cells (HSC) in which ZBTB1 gene expression is knocked down by RNAi will provide new insight into lymphoid development. Thus the goals of this proposal are to (i) assemble samples from SCID and CID patients without known gene defects; (ii) explore SCID pathogenesis of B cell impairment in Zbtb1- mice; (iii) use parallel in vitro and in vivo strategies to compare lymphoid developmental potential of HSC from wild type vs. Zbtb1 knockout mice and normal vs. ZBTB1 knockdown cord blood stem cells; and (iv) find Zbtb1 interacting partners and gene targets, which (along with ZBTB1 itself) will be assessed for mutations that may cause human SCID. PUBLIC HEALTH RELEVANCE: The development of lymphocytes from blood-forming stem cells is incompletely understood, but critically important for treating humans with severe combined immunodeficiency (SCID), other immune and blood diseases, and cancers. We study humans and mice with SCID to find their underlying gene defects and to learn about pathways essential for lymphocyte maturation. We discovered that mice lacking Zbtb1 (a previously unstudied zinc finger protein) cannot form T lymphocytes, though B lymphocytes are present. Zbtb1 is related to transcription factors that repress expression of their target genes. We will investigate how Zbtb1 and its targets function in developing mouse and human lymphoid cells and determine whether defects in Zbtb1 or the genes it acts upon cause human disorders of immunity.