Mechanisms regulating neural progenitor expansion in the developing brain

调节大脑发育中神经祖细胞扩张的机制

• 批准号: 9557551
• 负责人: Jianfu Chen
• 金额: $ 36.09万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9557551
• 关键词: Ablation; Alleles; Binding; Biogenesis; Biological Assay; Body Size; Brain; Cell Cycle; Cell Cycle Progression; Cell Death; Cells; Centrioles; Chromosomes; Cilia; Data; Defect; Disease; Embryo; Exhibits; Fibroblasts; Funding; GTP-Binding Protein alpha Subunits, Gs; Genetic; Genetic study; Goals; Grant; Human; Human Genetics; Individual; Intellectual functioning disability; Lead; Length; Link; Microcephaly; Mitosis; Mitotic; Modeling; Mus; Mutant Strains Mice; Mutation; Nonsense Mutation; Online Mendelian Inheritance In Man; Organ; Patients; Phenocopy; Play; Population; Positioning Attribute; Proteins; Regulation; Role; Specificity; Staining method; Stains; Testing; alpha Tubulin; brain size; cilium biogenesis; congenital brain disorder; improved; insight; kinetosome; knock-down; mouse model; mutant; nerve stem cell; neuroregulation; novel

Project Summary Recent human genetic studies identified a link between a class of centrosomal proteins and microcephaly, which is characterized by a selective reduction of brain size in comparison to other organs. The goal of this proposal is to establish a novel mechanism of microcephaly by understanding how dysregulation of mitotic progression and cell cycle re-entry leads to neural progenitor cell (NPC) reduction in microcephaly. This contrasts with the dominant model in the field that disruption of symmetric/asymmetric division of NPCs causes microcephaly. We will test this mechanism by focusing on WDR62 (MCPH2; OMIM 604317), which is the second most common genetic cause of human microcephaly and encodes a WD-40 repeat protein. We created a hypomorphic mouse model of Wdr62 deficiency and found that mutant mice exhibited reduced brain sizes due to a decrease in NPCs. Wdr62 deficient NPCs exhibit mitotic progression delay and an increase in cell death. Wdr62 deficient mouse embryonic fibroblasts (MEFs) showed reduced spindle stability and spindle assembly checkpoint (SAC) activation. Wdr62 physically and genetically interacts with Aurora A, an established spindle assembly factor. In addition, Wdr62 localizes to the basal bodies of primary cilia and regulates cilia disassembly and cell cycle re-entry of MEFs. Depletion of Cep170, another Wdr62 interacting protein, also results in cilia disassembly, suggesting that Wdr62 may function together with Cep170 to regulate cilia biogenesis and cell cycle progression. These preliminary data lead to a novel hypothesis that Wdr62 regulates neural progenitor expansion in the developing brain by influencing mitotic progression and cell cycle re-entry, which are disrupted by disease mutations in a specific manner. To test this hypothesis, three specific aims will be pursued: 1) Test the hypothesis that Wdr62 regulates mitotic progression of neural progenitor cells (NPCs) by influencing spindle integrity; 2) Test the hypothesis that Wdr62 regulates cilia disassembly and cell cycle re-entry by functioning together with Cep170; 3) Test the hypothesis that individual disease alleles of WDR62 compromise its specific functions (mitosis or cilia disassembly) due to loss of regulation of specific Wdr62 interacting proteins. Together, these studies will improve our understanding of mitosis and cell cycle re-entry regulation of NPCs in the developing brain and provide novel insights into mechanisms underlying human microcephaly diseases.

项目摘要 最近的人类遗传研究确定了一类中心蛋白与小头畸形之间的联系，这是 与其他器官相比，具有选择性减小脑大小的特征。该提议的目的是 通过了解有丝分裂进展的失调和 细胞周期的重新进入导致小头畸形的神经祖细胞（NPC）降低。这与 NPC的对称/不对称分裂破坏的领域中的主要模型会导致小头畸形。 我们将通过关注WDR62（MCPH2; OMIM 604317）来测试此机制，这是第二个 人类小头畸形的常见遗传原因并编码WD-40重复蛋白。 我们创建了WDR62缺乏症的肌型小鼠模型，发现突变小鼠表现出 由于NPC的减少，大脑尺寸减小。 WDR62缺乏NPC表现出有丝分裂进展延迟和 细胞死亡的增加。 WDR62缺乏小鼠胚胎成纤维细胞（MEF）显示纺锤稳定性降低 和主轴组件检查点（SAC）激活。 WDR62在物理和遗传上与Aurora A相互作用， 已建立的主轴装配因子。此外，WDR62本地化于原发性纤毛的基体和 调节MEF的纤毛分解和细胞周期重新进入。 CEP170的耗竭，另一个WDR62相互作用 蛋白质也导致纤毛拆卸，表明WDR62可能与CEP170一起起作用以调节 纤毛生物发生和细胞周期进程。这些初步数据导致了一个新的假设，即WDR62 通过影响有丝分裂进展和细胞周期来调节发育中大脑中神经祖细胞的扩展 重新进入，以特定方式被疾病突变破坏。 为了检验这一假设，将追求三个具体目标：1）检验WDR62调节的假设 通过影响纺锤体完整性，神经祖细胞（NPC）的有丝分裂进展； 2）检验假设 WDR62通过与CEP170一起运行来调节纤毛脱隔离和细胞周期重新进入； 3）测试 假设WDR62的个体疾病等位基因会损害其特定功能（有丝分裂或纤毛 拆卸）由于特定WDR62相互作用蛋白的调节丢失。这些研究将在一起 提高我们对发育中大脑中NPC的有丝分裂和细胞周期的理解，并 对人类小头疾病的基础机制提供新的见解。