OXYSTEROL BIOMARKERS FOR NIEMANN-PICK C DISEASE

描述(申请人提供)：Niemann-Pick C1型(NPC1)病是一种罕见的进行性神经退行性疾病，其特征是胆固醇和其他脂质在内脏和中枢神经系统积聚。开发NPC1疾病治疗方法的一个障碍是缺乏在临床试验中评估治疗效果的容易量化的结果衡量标准。通过广泛的代谢组学努力，我们在NPC1受试者中发现了胆固醇氧化产物(“氧化甾醇”)生物标志物，它们反映了氧化应激和未酯化胆固醇储存的独特交集--这是NPC1疾病的生化标志。这项建议测试了一个高度创新的假说，即氧合固醇生物标记物与其他胆固醇稳态标记物一起，可以作为结果指标来评估疾病修饰疗法(例如，2-羟丙基-�-环糊精、HP-�-CD)对中枢神经系统胆固醇代谢的影响，并监测疾病进展。24(S)-HC(几乎仅在中枢大神经元中合成)和脑脊液胆固醇酯(CE)为指导给药和监测药物反应提供了潜在的定量、非侵入性指标。同样，我们先前发现在NPC1受试者脑脊液中升高的Cholestane-3�，5�，6�-Triol(“三醇”)将告知HP-�-CD对神经元内胆固醇储存的影响。这一假设将在脑室内注射HP-�-CD的NPC1动物模型(AIM 1)以及在自然病史研究和美国国立卫生研究院临床中心脑室Hp-�-CD的1期试验(AIM 2)中登记的NPC1人类受试者中进行验证。该提案还将探讨利用Triol分析的特殊受试者工作特征(ROC)开发新筛查的可能性，以更早地识别NPC1患者，从而干预症状前患者(目标3)。拟议的新生儿NPC1疾病筛查是创新的，将是第一次针对非酶溶酶体疾病的筛查，也是第一次针对先天的类固醇代谢错误的筛查。虽然该项目的目标是开发适合在全州或地区一级实施的NPC1疾病的新生儿筛查原型，但为提取和检测氧化甾醇而开发的串联质谱学方法可以很容易地扩展到在其他类固醇紊乱症(例如Smith-Lemli-Opitz综合征)中积累的代谢物，从而允许在单一筛查的背景下对几种遗传性疾病进行多路筛查。这项提案中的研究具有非常重要的意义，因为我们解决了NPC1疾病尚未得到满足的关键治疗和诊断需求。

DESCRIPTION (provided by applicant): Niemann-Pick type C1 (NPC1) disease is a rare, progressive neurodegenerative disorder characterized by accumulation of cholesterol and other lipids in the viscera and central nervous system. A barrier to the development of treatments for NPC1 disease is the lack of readily quantifiable outcome measures to evaluate efficacy of therapy in clinical trials. Through broad-based metabolomic efforts, we have discovered in NPC1 subjects cholesterol oxidation product ("oxysterol") biomarkers that reflect the unique intersection of oxidative stress and unesterified cholesterol storage - the biochemical hallmark of NPC1 disease. This proposal tests the highly innovative hypothesis that oxysterol biomarkers, together with other cholesterol homeostatic markers, can serve as outcome measures to assess the effect of disease-modifying therapies (e.g., 2-hydroxypropyl-�-cyclodextrin, HP-�-CD) on cholesterol metabolism in the CNS and to monitor disease progression. 24(S)-HC, which is synthesized almost exclusively in large neurons in the CNS, and CSF cholesteryl esters (CE) offer potential quantitative, non-invasive metrics to guide dosing and to monitor drug response. Likewise, cholestane-3�, 5�, 6�-triol ("triol"), which we have previously shown to be elevated in the CSF of NPC1 subjects, will inform with respect to the effect of HP-�-CD on intraneuronal cholesterol storage. This hypothesis will be tested in NPC1 animal models administered intracerebroventricular (ICV) HP-�-CD (Aim 1), and in NPC1 human subjects enrolled in a natural history study and in a Phase 1 trial for ICV HP-�-CD at the NIH Clinical Center (Aim 2). The proposal will also explore the possibility that the exceptional receiver operating characteristics (ROC) of the triol assay can be harnessed to develop a newborn screen to identify NPC1 patients earlier and thus intervene in pre-symptomatic patients (Aim 3). The proposed newborn screen for NPC1 disease is innovative and would be the first for a non-enzymatic lysosomal disorder, as well as the first for an inborn error of sterol metabolism. While the goal of this project is to develop a prototype newborn screen for NPC1 disease suitable for implementation at the statewide or regional level, the tandem mass spectrometry methods developed for extraction and detection of the oxysterols could be readily extended to metabolites that accumulate in other sterol disorders (e.g., Smith-Lemli-Opitz Syndrome), thereby permitting multiplexed screening for several inherited disorders within the context of a single screen. The studies in this proposal are highly significant because we address the critical unmet therapeutic and diagnostic needs of NPC1 disease.