Neurogenesis: Career Development Plan in the Genetic and Modeling of Microcephaly

描述(申请人提供)：人类遗传学、动物模型和最近将诱导多能干细胞(IPSCs)添加到人类神经发育疾病建模工具箱中的组合，有可能极大地扩展我们对人类疾病机制的理解。到目前为止，理解人类神经发育障碍的一个主要挑战是缺乏受影响的组织。IPSC能够从患者的IPSC中分化出完整的神经组织，从神经前体细胞(NP)到成熟的皮质神经元，为理解疾病的独特人类特征开辟了一条令人兴奋的新途径。在这项应用中，我建议定制这项新技术来模拟常染色体隐性遗传性原发性小头症(MCPH)背后的神经发生缺陷。MCPH是一种神经发育障碍，其特征是宫内头部生长严重减退，并伴有非进行性智力低下。MCPH是大脑皮层发育不良和大脑结构正常的广泛性萎缩的结果，这种表型被认为是发育早期NP增殖缺陷的结果。MCPH非常适合这种新的建模方法，因为NPs在IPSC分化方案的早期就进行了分化，并且增殖可以在神经花环的背景下进行评估。为了将IPSCs体外建模数据与体内脑发育相关联，我建议使用患者IPSCs、转基因小鼠IPSCs和动物模型的组合。为了测试IPSC建模传达独特机制信息的敏感性，我建议对MCPH的两个遗传原因进行建模，这两个遗传原因应该以不同的方式或不同的严重程度干扰同一组细胞。为了更全面地了解MCPH在神经发生中的作用，根据上面描述的技术，我建议同时对Nucleopin 107(NUP107)和异常纺锤体样小头畸形(ASPM)进行建模。我最近发现了核孔蛋白107(NUP107)，这是一个以前与人类疾病无关的基因，是MCPH的致病基因。为了进行这项拟议的研究，我从Nup107患者和对照成纤维细胞以及嵌合体小鼠中产生了条件NUP107基因陷阱等位基因(NUP107GT)的IPSCs。我还发现了一种新的ASPM突变，这是MCPH中最常见的突变基因，IPSC模型将作为独立调查者进行研究。从MCPH的这种建模方法中可以获得的机械理解水平将为导致新的治疗方法和对正常人脑如何发育的洞察奠定基础。 公共卫生相关性：原发性小头畸形是一种神经发育障碍，可能是由于神经发生改变，导致大脑生长严重减慢。我已经确定了一个新的致病基因NUP107，并提议研究诱导多能干细胞和基因敲除小鼠来模拟这种人类疾病。

DESCRIPTION (provided by applicant): The combination of human genetics, animal models and the recent addition of induced pluripotent stem cells (iPSCs) to the human neurodevelopmental disease modeling toolbox has the potential to greatly expand our understanding of human disease mechanisms. To date, a major challenge to understanding human neurodevelopmental disorders has been the lack of affected tissue. The capacity of iPSCs to differentiate the full complement of neural tissue, from neural progenitors (NP) to mature cortical neurons, from patient iPSC opens an exciting new avenue to understanding unique human features of disease. In this application, I propose to tailor this new technology to model defects in neurogenesis which underlie autosomal recessive primary microcephaly (MCPH). MCPH is a neurodevelopmental disorder characterized by a great reduction of head growth in utero and is accompanied by nonprogressive mental retardation. MCPH is the result of cerebral cortex hypoplasia and generalized diminution of an otherwise architecturally normal brain, a phenotype that is thought to result from defective NP proliferation early in development. MCPH is well suited for this new modeling approach as NPs differentiate early in iPSC differentiation protocols and proliferation can be evaluated within the context of neural rosettes. To correlate iPSCs in vitro modeling data to in vivo brain development, I propose to utilize a combination of patient iPSCs, transgenic mouse iPSCs and animal models. To test the sensitivity of iPSC modeling to convey unique mechanistic information, I propose to model two genetic causes for MCPH that should perturb the same set of cells in different ways or with varying severity. To gain a more comprehensive understanding of the role of in neurogenesis in the molecular pathology of MCPH according to the techniques described above I am proposing to model both Nucleoporin 107 (NUP107) and abnormal spindle-like microcephaly associated (ASPM). I recently identified Nucleoporin 107 (NUP107), a gene not previously linked to human disease, as a causative gene for MCPH. To pursue the proposed research, I have generated iPSCs from Nup107 patient and control fibroblasts and chimeric mice for a conditional NUP107 gene trap allele (NUP107GT). I have also identified a novel ASPM mutation, the gene most commonly mutated in MCPH, for which iPSC modeling will be pursued as an independent investigator. The level of mechanistic understanding that can be gained from this modeling approach for MCPH will lay the foundation that can lead to new therapies and insights into how the normal human brain develops. PUBLIC HEALTH RELEVANCE: Primary microcephaly is a neurodevelopmental disorder presumably due to altered neurogenesis and causing a great reduction in brain growth. I have identified a new causative gene, NUP107, and propose to study induced-pluripotent stem cells and knockout mice to model this human disease.