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

• 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
• 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

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，丝粒不稳定性和面部异常（ICF）综合征是一种罕见的常染色体 隐性疾病，绝大多数病例在DNA甲基转移酶基因中携带突变 DNMT3B（ICF1）或锌指蛋白基因ZBTB24（ICF2）。 ICF综合征的标志是DNA的丧失 特定基因组区域的甲基化，据信这是其他表型的主要缺陷 异常，包括抗体缺乏症（低毛细血管素血症），面部畸形和心理 迟钝。 ICF综合征患者通常在幼儿时期死于复发性感染。虽然ICF 综合征最初是在将近四十年前报告的 该疾病的发病机制很大程度上是由于缺乏适当的体外和体内模型。造型 使用DNMT3B突变小鼠的ICF综合征是一个挑战，因为DNMT3B的完全失活 导致胚胎致死性，带有ICF样点突变的小鼠无法概括抗体缺乏症。 申请人实验室的初步数据表明，小鼠胚胎干细胞中的ZBTB24耗竭 （ESC）导致大量DNMT3B下调和DNA甲基化改变ICF的特征 综合征和造血谱系中的条件ZBTB24缺失导致严重 小鼠中的低磁性血症，显然是由于浆细胞分化或存活率缺陷。这 该应用的目的是确定ZBTB24在调节DNA甲基化和 抗体产生。中心假设是ZBTB24通过调节DNMT3B表达来控制DNA 淋巴细胞种群中甲基化，基因表达和染色质结构，对 抗体产生。申请人建议使用ZBTB24缺陷ESC阐明分子 ZBTB24调节DNMT3B表达并确定ZBTB24缺乏对ZBTB24的机制 DNA甲基化，基因表达和染色质结构（AIM 1）。申请人还建议使用 ZBTB24突变ICF小鼠模型，以确定抗体缺乏症和 阐明异常DNA甲基化与基因表达缺陷之间的联系，染色质结构 和有助于抗体缺乏的分子信号传导（AIM 2）。该项目很重要，因为 拟议工作的结果不仅将从根本上提高对ICF的机理理解 综合征，但也可以阐明其他抗体缺乏疾病的病因和缺陷， 包括常见的可变免疫缺陷（CVID）。这些结果也将在 了解表观遗传机制在免疫和免疫疾病中的作用。该项目有 潜在的翻译影响，因为拟议工作的结果可能导致识别 ICF综合征和其他免疫缺陷疾病的新型治疗策略以及创新的ICF 将来，小鼠模型对于临床前测试可能是有价值的。