Modeling ICF syndrome in mice: Role of Zbtb24 in DNA methylation and antibody production

小鼠 ICF 综合征建模：Zbtb24 在 DNA 甲基化和抗体产生中的作用

基本信息

批准号：
9755338
负责人：
Taiping Chen
金额：
$ 40万
依托单位：
UNIVERSITY OF TX MD ANDERSON CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-26 至 2021-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9755338
关键词：
Aberrant DNA Methylation Affect Antibodies Antibody Formation Autoimmunity B-Cell Development B-Lymphocytes Biological Process Cause of Death Cell Culture Techniques Cell Survival Cell physiology Characteristics Chromatin Chromatin Structure Clinical Common Variable Immunodeficiency DNA DNA Methylation DNA Methylation Regulation DNA Modification Methylases DNA-Binding Proteins DNMT3B gene Data Defect Deficiency Diseases Development Disease Down-Regulation Embryo Epigenetic Process Etiology Face Future Gene Expression Gene Proteins Genes Genetic Transcription Genomic Segment HELLS gene Health Hematopoietic Immune System Diseases Immunity Immunoglobulin-Secreting Cells Immunologic Deficiency Syndromes Impairment In Vitro Individual Infection Knockout Mice Knowledge Laboratories Lead Light Link Lymphocyte Mental Retardation Mission Modeling Molecular Mus Mutant Strains Mice Mutation Outcome Pathogenesis Pathway interactions Patients Phenotype Point Mutation Population Preclinical Testing Public Health Recurrence Regulation Reporting Research Role Signal Transduction T-Lymphocyte United States National Institutes of Health Work Zinc Fingers cell type chromatin remodeling early childhood embryonic stem cell gene function genome-wide helicase hypogammaglobulinemia immunodeficiency-centromeric instability-facial anomalies syndrome improved in vivo in vivo Model innovation mouse model mutant novel therapeutics plasma cell differentiation programs therapeutic evaluation tool transcription factor translational impact

项目摘要

The Immunodeficiency, Centromeric instability, and Facial anomalies (ICF) syndrome is a rare autosomal recessive disorder, with the vast majority of cases carrying mutations in either the DNA methyltransferase gene DNMT3B (ICF1) or the zinc finger protein gene ZBTB24 (ICF2). A hallmark of ICF syndrome is loss of DNA methylation in specific genomic regions, which is believed to be the primary defect underlying other phenotypic abnormalities, including antibody deficiency (hypogammaglobulinemia), facial dysmorphism, and mental retardation. Patients with ICF syndrome usually die of recurrent infections in early childhood. Although ICF syndrome was first reported nearly four decades ago, little progress has been made in understanding the pathogenesis of the disease, largely because of the lack of appropriate in vitro and in vivo models. Modeling ICF syndrome using Dnmt3b mutant mice has been a challenge, because complete inactivation of Dnmt3b leads to embryonic lethality and mice carrying ICF-like point mutations fail to recapitulate antibody deficiency. Preliminary data from the applicant's laboratory revealed that Zbtb24 depletion in mouse embryonic stem cells (ESCs) results in substantial Dnmt3b downregulation and DNA methylation alterations characteristic of ICF syndrome and that conditional Zbtb24 deletion in the hematopoietic lineage leads to severe hypogammaglobulinemia in mice, apparently due to defects in plasma cell differentiation or survival. The objective of this application is to determine the role of Zbtb24 in the regulation of DNA methylation and antibody production. The central hypothesis is that Zbtb24, via regulating Dnmt3b expression, controls DNA methylation, gene expression, and chromatin structure in lymphocyte populations that are important for antibody production. The applicant proposes to use Zbtb24-deficient ESCs to elucidate the molecular mechanism by which Zbtb24 regulates Dnmt3b expression and determine the impacts of Zbtb24 deficiency on DNA methylation, gene expression, and chromatin structure (aim 1). The applicant also proposes to use the Zbtb24-mutant ICF mouse model to determine the cellular defects involved in antibody deficiency and elucidate the links between aberrant DNA methylation and the defects in gene expression, chromatin structure and molecular signaling that contribute to antibody deficiency (aim 2). The project is significant, because results from the proposed work will not only fundamentally advance mechanistic understanding of ICF syndrome, but could also shed light on the etiology and defects underlying other antibody deficiency diseases, including common variable immunodeficiency (CVID). These results will also have general implications in understanding the role of epigenetic mechanisms in immunity and immunological disorders. The project has potential translational impact as well, because results from the proposed work could lead to identification of novel therapeutic strategies for ICF syndrome and other immunodeficiency diseases, and the innovative ICF mouse model could be valuable for preclinical testing of therapeutics in the future.

免疫缺陷、着丝粒不稳定和面部异常 (ICF) 综合征是一种罕见的常染色体综合征隐性遗传病，绝大多数病例携带 DNA 甲基转移酶基因突变 DNMT3B (ICF1) 或锌指蛋白基因 ZBTB24 (ICF2)。 ICF 综合征的一个标志是 DNA 丢失特定基因组区域的甲基化被认为是其他表型的主要缺陷异常，包括抗体缺乏（低丙种球蛋白血症）、面部畸形和精神障碍迟缓。 ICF 综合征患者通常在儿童早期死于反复感染。虽然ICF 综合征在近四十年前首次被报道，但在理解该综合征方面进展甚微该病的发病机制，很大程度上是因为缺乏合适的体外和体内模型。造型使用 Dnmt3b 突变小鼠进行 ICF 综合征一直是一个挑战，因为 Dnmt3b 完全失活导致胚胎致死，并且携带 ICF 样点突变的小鼠无法重现抗体缺陷。申请人实验室的初步数据显示，小鼠胚胎干细胞中 Zbtb24 缺失 (ESC) 导致 Dnmt3b 大幅下调和 ICF 特征的 DNA 甲基化改变综合征，并且造血谱系中的条件性 Zbtb24 缺失会导致严重的小鼠低丙种球蛋白血症，显然是由于浆细胞分化或存活缺陷所致。这本申请的目的是确定 Zbtb24 在 DNA 甲基化调节中的作用和抗体的产生。中心假设是 Zbtb24 通过调节 Dnmt3b 表达来控制 DNA 淋巴细胞群中的甲基化、基因表达和染色质结构对于抗体的产生。申请人建议使用Zbtb24缺陷的ESC来阐明分子 Zbtb24 调节 Dnmt3b 表达的机制并确定 Zbtb24 缺陷对 DNA 甲基化、基因表达和染色质结构（目标 1）。申请人还建议使用 Zbtb24 突变 ICF 小鼠模型，用于确定与抗体缺陷相关的细胞缺陷和阐明异常 DNA 甲基化与基因表达、染色质结构缺陷之间的联系以及导致抗体缺陷的分子信号传导（目标 2）。该项目意义重大，因为拟议工作的结果不仅将从根本上促进对 ICF 的机制理解综合征，但也可以揭示其他抗体缺乏疾病的病因和缺陷，包括常见变异型免疫缺陷病 (CVID)。这些结果也将具有普遍意义了解表观遗传机制在免疫和免疫疾病中的作用。该项目有还有潜在的转化影响，因为拟议工作的结果可能导致确定 ICF综合征和其他免疫缺陷疾病的新治疗策略，以及创新的ICF 小鼠模型对于未来治疗的临床前测试可能很有价值。