APO D CHOLESTEROL STORAGE AND NEURODEGENERATION

APO D 胆固醇储存和神经变性

• 批准号: 2273537
• 负责人: Shutish C. Patel
• 金额: $ 26.8万
• 依托单位: NEW ENGLAND BIOMEDICAL RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-30 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2273537
• 关键词: Niemann Pick disease; animal genetic material tag; apolipoproteins; blood lipoprotein metabolism; blood lipoprotein transport; cholesterol; disease /disorder model; fibroblast growth factor; inborn lipid storage disorder; laboratory mouse; molecular cloning; molecular pathology; myelination; neural degeneration; oligodendroglia; protein kinase C; tissue /cell culture

DESCRIPTION (Investigator's Abstract): This proposal aims to delineate the molecular and cellular neurobiology of the human neurodegenerative disorder, Niemann-Pick disease type C (NPC). NPC and its animal model, the cholesterol storage disorder (csd) mouse have been mapped to the pericentomeric region of chromosome 18, although the defective gene has not yet been identified. Two additional neurological mouse mutants, the ataxic (ax) and twirler (tw) are closely linked to the csd locus. A salient feature of NPC and csd is the abnormal accumulation of lysosomal cholesterol and other lipids which is associated with an attenuation of the normal homeostatic responses elicited by mammalian cells with lipoprotein uptake (stimulation of cholesterol ester synthesis, suppression of de novo cholesterol synthesis and down-regulation of LDL receptor activity). The investigators have established that processing of the 30 kD cholesterol binding protein, apolipoprotein (apo) D is deficient in cultured csd astrocytes and there is intracellular retention of a novel 46 kD apo D-immunoreactive protein that serves as a biochemical marker of the mutant cells. The investigators propose to determine the identity and role of this novel 46 kD apo D-immunoreactive protein in csd. To further investigate the role of apo D as an intracellular cholesterol transport protein in neural and non-neural cells, the investigators will use state-of-the-art biophysical techniques to investigate apo D-ligand interactions in cell free systems and in single live cells. Since apo D is a member of the lipocalin family of small hydrophobic ligand carrier proteins (examples of which include retinal binding protein, beta-lactoglobulin and odorant binding protein), these studies will provide new information on the structure- function correlates of apo D binding to cholesterol and related ligands as well as provide new insights into the mechanisms of ligand transport by lipocalins in general. The major phenotypic features of NPC and csd mouse reflect neurodegeneration with hypomyelination and a selective loss of cerebellar Purkinje cells. The investigators have established that secretion of the potent mitogen and growth factor, basic fibroblast factor (bFGF) from cultured astrocytes is deficient. This deficiency is associated with a maturational defect of oligodendrocytes in csd brain. Furthermore, expression of protein kinase C (PKC) which has been shown to be crucial for the expression of myelin protein genes during oligodendrocyte development, is restricted in csd brain. The investigators will therefore investigate the role of growth factors especially bFGF, as well as apo D, in oligodendroglial maturation and of PKC in the hypomyelination of csd brain. Finally, upon identification of the human NPC gene, the investigators propose to clone the mouse homolog of human gene in order to establish its relationship to the human mutation and to determine whether tw and ax are caused by a similar genetic defect(s). These studies will provide new insights into the molecular defect of human NPC and its mouse model, csd, as well as lead to a better understanding of the mechanisms of neurodegeneration in these inherited disorders.

描述（研究者的摘要）：该提案旨在划定 人神经退行性的分子和细胞神经生物学 疾病，Niemann-Pick疾病C型（NPC）。 NPC及其动物模型， 胆固醇存储障碍（CSD）小鼠已映射到 染色体第18染色体的周期体区域，尽管有缺陷的基因具有 尚未确定。另外两个神经小鼠突变体， 共济失调（AX）和旋转器（TW）与CSD基因座密切相关。一个 NPC和CSD的显着特征是溶酶体异常积累 胆固醇和其他脂质与衰减有关 哺乳动物细胞引起的正常稳态反应 脂蛋白摄取（刺激胆固醇酯的合成， 抑制从头胆固醇合成和LDL的下调 受体活性）。调查人员已经确定了处理 在30 kD的胆固醇结合蛋白中，载脂蛋白（APO）D为 缺乏培养的CSD星形胶质细胞，细胞内有 保留新型46 kd apo d-免疫反应性蛋白 突变细胞的生化标记。调查人员建议 确定这款46 kD apo d-imunoreactive的身份和作用 CSD中的蛋白质。进一步研究apo d作为一个 神经和非神经中细胞内胆固醇转运蛋白 细胞，研究人员将使用最先进的生物物理 研究无细胞系统中apo d-d-coots相互作用的技术 并在单个活细胞中。由于Apo D是Lipocalin的成员 小型疏水配体载体蛋白的家族（其示例 包括视网膜结合蛋白，β-乳球蛋白和气味结合 蛋白质），这些研究将提供有关结构的新信息 - Apo d结合与胆固醇和相关配体的功能相关 以及对配体运输机制的新见解 一般来说是脂质蛋白。 NPC和CSD的主要表型特征 小鼠反映神经退行性的降低和选择性 小脑Purkinje细胞的丧失。调查人员已经建立了 有效有丝分裂原和生长因子的分泌，基本成纤维细胞 来自培养的星形胶质细胞的因子（BFGF）不足。这种缺陷是 与CSD脑中少突胶质细胞的成熟缺陷有关。 此外，蛋白激酶C（PKC）的表达已显示 对于髓磷脂蛋白基因的表达至关重要 少突胶质细胞的发展受到CSD脑的限制。这 因此，研究人员将研究增长因素的作用 尤其是BFGF，以及Apo d，在寡头成熟和 PKC在CSD脑的降压中。最后，识别 人类NPC基因的研究人员建议克隆小鼠 人类基因的同源物是为了建立其与 人类突变并确定TW和AX是否是由A引起的 相似的遗传缺陷。这些研究将为您提供新的见解 人NPC及其小鼠模型CSD的分子缺陷以及 可以更好地理解神经退行性的机制 在这些遗传疾病中。