CNS DEFECT IN A MURINE ZELLWEGER SYNDROME MODEL

描述(摘自申请者摘要)：齐薇格综合征是一种 导致神经元异常的人类过氧化物体生物发生障碍 中枢神经系统的迁移和严重的神经功能障碍。校长 研究人员开发了一种针对这种疾病的小鼠模型 PEX2过氧化物体基因的缺失，并证明存在 新生小鼠的过氧化物体缺陷和大脑皮层异常。 在出生后存活的PEX2缺陷小鼠也会发展成严重的 小脑异常。在近亲交配的品系中，PEX2小鼠似乎会发育 广泛的神经元性脂肪沉积症，集中在下部 橄榄核。这些小鼠提供了一个重要的动物模型来理解 过氧化体功能在中枢神经系统发育中的作用。首席调查员 提出了一系列整合的细胞和分子研究，开始 回答以下问题。1.过氧化物酶的作用是什么？ 神经元增殖、迁移、存活和分化方面的缺陷 在小鼠中枢神经系统发育过程中？神经前体细胞将在体内被标记 有丝分裂标志物或逆转录病毒感染及其增殖率， 随后的迁移和最终的分化检查。调查员将 用视频直接显示体外迁移神经元的动力学 用培养的脑片进行显微镜观察。中发生的架构变化 突变的大脑将用细胞类型特定的标记进行检查，这些标记具有 确定的发展模式，以确定的开始和演变的 过氧核糖体病过程。超微结构研究将进一步定义 细胞类型特异性过氧化物体病理在不同阶段的观察 发展。过氧化体缺乏症对神经元存活和功能的影响 将检查迁移后的分化情况。2.细胞的作用是什么 自主功能与表观遗传因素在导致发育中的作用 缺陷？将使用两个主要战略来解决这个问题，并 包括：a.体内移植正常或过氧化物酶体缺陷神经元 祖细胞进入正常或突变的发育皮质。这些研究将 评估在过氧化物酶体脑中观察到的细胞缺陷 缺陷神经元是神经元固有的，而不是继发性的 其他脑细胞和/或环境变化；B.肝脏/肠道特异性 PEX2转基因表达纠正肝脏过氧化物体异常和 评估循环中的有毒因素和/或营养不良的作用 肝功能障碍与脑固有代谢在导致中枢神经系统中的作用 缺陷。

DESCRIPTION (Verbatim from the Applicant's Abstract): Zellweger syndrome is a human peroxisomal biogenesis disorder that results in abnormal neuronal migrations in the CNS and severe neurologic dysfunction. The principal investigator has developed a murine model for this disorder by targeted deletion of the PEX2 peroxisomal gene and has demonstrated the presence of peroxisomal defects and a cerebral cortical abnormality in newborn mice. PEX2-deficient mice that survive in the postnatal period also develop severe cerebellar abnormalities. In an inbred strain, PEX2 mice appear to develop extensive neuronal lipidosis, with a prominent concentration in the inferior olivary nucleus. These mice provide an important animal model to understand the role of peroxisomal function during CNS development. The principal investigator proposes an integrated series of cellular and molecular studies to begin to answer the following questions. 1. What is the effect of the peroxisomal deficiency on neuronal proliferation, migration, survival, and differentiation during murine CNS development? Neuronal precursor cells will be labeled in vivo with mitotic markers or retroviral infection and their proliferative rate, subsequent migration and final differentiation examined. The investigator will directly visualize the dynamics of migrating neurons in vitro by video microscopy using cultured brain slices. The architectural changes that occur in the mutant brains will be examined with cell type specific markers having established developmental patterns to define the onset and the evolution of the peroxisomal disease process. Ultrastructural studies will define further the cell type specific peroxisomal pathology observed at various stages of development. The effect of peroxisomal deficiency on neuronal survival and postmigratory differentiation will be examined. 2. What is the role of cell autonomous function versus epigenetic factors in causing the developmental defects? Two major strategies will be used to approach this question and include: a. in vivo transplantation of normal or peroxisome-deficient neuronal progenitors into normal or mutant developing cortex. These studies will evaluate whether the cellular defects observed in the brain of peroxisome deficient neurons are intrinsic to the neurons versus secondary to defects in other brain cells and/or environmental alterations; and b. liver/gut specific PEX2 transgene expression to correct hepatic peroxisomal abnormalities and evaluate the role of circulating toxic factors and/or malnutritions that result from hepatic dysfunction versus intrinsic brain metabolism in causing the CNS defects.