A Humanized Mouse Model of Astrocytic Pathology in Schizophrenia

描述（由申请人提供）：人类进化伴随着星形胶质细胞表型和功能的多样化，这有助于人脑功能和疾病的物种特异性方面。因此，人类星形胶质细胞的复杂性的发展已经在人类特有的精神疾病-特别是精神分裂症-的进化中出现。然而，尽管星形胶质细胞病理学可能有助于精神分裂症的思维障碍，但星形胶质细胞病理学在其发病机制中的作用一直难以研究，部分原因是缺乏人类胶质细胞病理生理学的动物模型。我们建议克服这一限制，使用我们开发的人类神经胶质嵌合小鼠大脑的新模型，与我们新开发的方案配对，用于从患者来源的人类诱导多能细胞（hiPSC）有效和可靠地生成星形胶质细胞。我们将使用从精神分裂症患者产生的hiPSC衍生的胶质祖细胞（GPC）移植到小鼠体内，评估精神分裂症患者衍生的星形胶质细胞对疾病发病机制的具体贡献。在这些人神经胶质嵌合小鼠脑中，绝大多数常驻神经胶质被人GPC衍生的星形胶质细胞及其祖细胞取代，从而允许在活的成年小鼠中评估人神经胶质生理学、基因表达和对神经功能的影响。通过将这种嵌合方法与我们已经开发的用于从hiPSC产生和纯化GPC和星形胶质细胞的方案配对，并使用从青少年发作的精神分裂症患者产生的hiPSC系，我们将产生其常驻神经胶质细胞主要来源于精神分裂症患者的小鼠。在目标1中，我们将评估这些精神分裂症相关星形胶质细胞对嵌合小鼠皮质内胶质细胞合胞体传递的相对影响。在目标2中，我们接下来将评估嵌合小鼠的突触可塑性，以及精神分裂症衍生的神经胶质嵌合对其行为表型和对药理学应激的反应的影响。在目标3中，我们将从它们已经整合到其中的脑中分选移植的星形胶质细胞，以便评估精神分裂症iPSC衍生的星形胶质细胞相对于正常hiPSC衍生的胶质细胞的基因表达模式。通过这种多模式的方法，我们希望确定疾病特异性的影响，基因表达模式，和旁分泌毒性的精神分裂症hiPSC衍生的星形胶质细胞相对于正常hiPSC衍生的神经胶质细胞。这些不同的调查线应该为我们提供了很大的洞察人类星形胶质细胞在精神分裂症的发病机制中的物种和细胞类型特异性的作用。同时，通过提供新的人类神经胶质嵌合模型系统、精神分裂症患者源性星形胶质细胞形式的新细胞试剂以及涵盖精神分裂症hiPSC源性星形胶质细胞的新基因表达数据库，该项目应使我们能够为该领域提供广泛且令人兴奋的新工具、能力和数据库。总之，这些应该大大加速我们对精神分裂症发病机制中人类神经胶质功能障碍的理解。

DESCRIPTION (provided by applicant): Human evolution has been accompanied by a diversification of astrocytic phenotype and function, that has contributed to species-specific aspects of both human brain function and disease. As such, the development of human astrocytic complexity has paralleled the appearance in evolution of psychiatric disorders unique to humans - the schizophrenias in particular. Yet despite this correlative suggestion that astrocytic pathology might contribute to the disordered thought of schizophrenia, the role of astroglial pathology in its pathogenesis has been difficult to study, in part because of the lack o animal models of human glial pathophysiology. We propose to overcome this limitation, using a new model of human glial-chimeric mouse brains that we have developed, paired with our newly-developed protocols for efficiently and reliably generating astrocytes from patient-derived human induced pluripotential cells (hiPSCs). Using mice neonatally engrafted with glial progenitor cells (GPCs) derived from hiPSCs generated from schizophrenic patients, we will assess the specific contributions of schizophrenic patient-derived astrocytes to disease pathogenesis. In these human glial chimeric mouse brains, the vast majority of resident glia are replaced by human GPC-derived astrocytes and their progenitors, allowing human glial physiology, gene expression, and effects on neural function to be assessed in live adult mice. By pairing this chimerization approach with protocols that we have developed for both generating and purifying GPCs and astrocytes from hiPSCs, and using hiPSC lines produced from patients with juvenile-onset schizophrenia, we will produce mice whose resident glia are largely derived from patients with schizophrenia. In Aim 1, we will assess the relative effects of these schizophrenia-associated astrocytes upon glial syncytial transmission within the cortices of the chimeric mice. In Aim 2, we will next assess the synaptic plasticity of the chimeric mice, as well as the effects of schizophrenia-derived glial chimerization upon their behavioral phenotype and responses to pharmacological stressors. In Aim 3, we will sort engrafted astroglia from the brains into which they have integrated, so as to assess the gene expression patterns of schizophrenic iPSC-derived astrocytes, relative to those of normal hiPSC-derived glia. By means of this multimodal approach, we hope to define the disease-specific effects, gene expression patterns, and paracrine toxicities of schizophrenic hiPSC-derived astrocytes relative to normal hiPSC-derived glia. These diverse lines of investigation should provide us great insight into the species- and cell type-specific roles of human astrocytes in the pathogenesis of schizophrenia. At the same time, by providing a new human glial chimeric model system, new cellular reagents in the form of schizophrenic patient-derived astrocytes, and new gene expression databases covering schizophrenic hiPSC-derived astrocytes, this project should allow us to make available to the field a broad and exciting new set of tools, capabilities and databases. Together, these should greatly accelerate our understanding of human glial dysfunction in the pathogenesis of schizophrenia.