Mouse Model for Zellwege Syndrome

描述（改编自申请人摘要）：最近的研究表明， 胆固醇对大脑的正常发育至关重要， 神经系统主要依赖于胆固醇的从头生物合成。我们有 表明过氧化物酶体是胆固醇生物合成所必需的，这是由于 法呢基二磷酸（FPP）的整个生物合成途径 只存在于过氧化物酶体中。因此，过氧化物酶体 在中枢神经系统的这一过程中必须发挥关键的功能作用。但没有 关于过氧化物酶体类异戊二烯/胆固醇生物合成的信息是可用的 正常脑中的通路或异戊二烯代谢的区室化 在CNS。Zellweger综合征的动物模型（即，过氧化物酶体PEX 2 敲除小鼠）的方法。这些老鼠提供了重要的 模型，以研究CNS中过氧化物酶体功能在发病机制中的作用 这些疾病中观察到的神经异常。本提案中 我们提出了过氧化物酶体在 类异戊二烯/胆固醇在CNS和PEX 2敲除小鼠中的生物合成， CNS中的类异戊二烯/胆固醇生物合成显著改变。 为了检验这一假设，提出了以下具体目标： 1)确定过氧化物酶体在类异戊二烯/胆固醇生物合成中的作用 在正常新生小鼠脑中。新生儿类异戊二烯生物合成途径 小鼠脑将通过亚细胞分级分离、活性和 梯度组分的免疫印迹分析和免疫组织化学， 原位杂交技术。我们还将确定 过氧化物酶体分布和ER对甾醇/非甾醇的贡献 生物合成在发育过程中发生变化。 2)检测脂质成分和胆固醇/多萜醇代谢缺陷 在PEX 2缺陷小鼠中。我们将确定如何调节胆固醇 酶和途径中的限速步骤可以通过 胆固醇合成的分解，由于缺乏 过氧化物酶体 这些研究旨在确定是否有依据表明 在Zellweger小鼠中观察到的一些神经缺陷中存在胆固醇。 因此，比较PEX 2缺陷型小鼠中的类异戊二烯/胆固醇代谢， 而正常动物可以洞察到的机制（S）为 在敲除小鼠中观察到的神经学表型。

DESCRIPTION(adapted from applicant's abstract): Recent studies have indicated that cholesterol is essential for normal brain development and that the central nervous system depends mainly on de novo cholesterol biosynthesis. We have shown that peroxisomes are essential for cholesterol biosynthesis, due to the fact that the entire pathway for the biosynthesis of farnesyl diphosphate (FPP) from mevalonate is exclusively found in peroxisomes. Therefore, peroxisomes must play a critical functional role in this process in the CNS. However, no information is available on the peroxisomal isoprenoid/cholesterol biosynthesis pathway in normal brain or on the compartmentalization of isoprene metabolism in the CNS. An animal model for Zellweger syndrome (i.e., a peroxisomal PEX2 knockout mouse) has been recently developed. These mice provide an important model to study the role of peroxisomal function in the CNS in the pathogenesis of the neurological abnormalities observed in these diseases. In this proposal we address the hypothesis that peroxisomes have a central role in isoprenoid/cholesterol biosynthesis in the CNS and that in PEX2 knockout mice, the isoprenoid/cholesterol biosynthesis in the CNS is significantly altered. To test this hypothesis the following specific aims are proposed: 1) To determine the role of peroxisomes in isoprenoid/cholesterol biosynthesis in normal neonatal mouse brain. The isoprenoid biosynthetic pathway in neonatal mouse brain will be analyzed by subcellular fractionation, activity and immunoblot analysis of the gradient fractions, and immunohistochemistry and in situ hybridization techniques. We will also determine if the relative distribution of peroxisomal and ER contribution to sterol/non-sterol biosynthesis changes during development. 2) To test for defects in lipid composition and cholesterol/dolichol metabolism in PEX2 deficient mice. We will determine how the regulation of cholesterol enzymes and the rate limiting steps in the pathway may be altered by the decompartmentalization of cholesterol synthesis due to the absence of peroxisomes. The studies are designed to ascertain whether there is a basis to implicate cholesterol in some of the neurologic defects observed in the Zellweger mouse. Thus a comparison of isoprenoid/cholesterol metabolism in the PEX2 deficient and normal animals can render insight into the mechanism(s) for the neurological phenotype seen in the knockout mice.