Clinical variability and Cell autonomy of Krabbe leukodystrophy

克拉伯脑白质营养不良的临床变异性和细胞自主性

基本信息

批准号：
8823865
负责人：
Daesung Shin
金额：
$ 7.95万
依托单位：
STATE UNIVERSITY OF NEW YORK AT BUFFALO
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8823865
关键词：
Address Affect Age-Years Alleles Antibodies Astrocytes Attenuated Behavior Blood Cells Brain Cause of Death Cell Fractionation Cell Nucleus Cell membrane Cells Centrifugation Cessation of life Child Clinical Clinical Research Coculture Techniques Conditioned Culture Media Cytosol DNA Data Demyelinating Diseases Demyelinations Deterioration Diagnosis Disease Disease Management Enzymes Fractionation Gene Expression Genes Genetic Polymorphism Genotype Globoid cell leukodystrophy Goals Golgi Apparatus High Pressure Liquid Chromatography IGF Type 2 Receptor Lysosomes Measures Mediating Methods Microglia Mitochondria Mus Mutation Mutation Analysis Nerve Degeneration Neuroglia Neurologic Neurons Oligodendroglia Organelles Outcome Pathology Pathway interactions Patients Phenotype Process Processed Genes Prognostic Marker Proteins Psychosine Reporting Retinal Ganglion Cells Reverse Transcriptase Polymerase Chain Reaction Secondary to Symptoms Testing Therapeutic Time Toxic effect Transplantation Western Blotting Work axonal degeneration base brain cell cell type combinatorial design diagnosis design effective therapy gene function hematopoietic cell transplantation improved infancy innovation inorganic phosphate killings loss of function mortality mouse model mutant myelin degeneration myelination outcome forecast peroxisome public health relevance research study reuptake trafficking

项目摘要

DESCRIPTION (provided by applicant): The goal of this proposal is two-fold: 1) to understand why the same mutation in the galactosylceraminidase (Galc) gene results in ample clinical variability among Krabbe leukodystrophy patients, and 2) to understand if brain cells other than oligodendrocytes are directly targeted by GALC deficiency. Answers to these two questions are crucially important for accurate diagnosis and for the design of more effective therapies. This disease is due to autosomal recessive mutations in the lysosomal enzyme GALC, which cause severe demyelination and neurodegeneration. More than 85% of Krabbe patients show infantile-onset, progressive neurologic deterioration and death by two years of age, while others have a late onset, less severe disease. This disease is diagnosed by measuring GALC activity and confirmed by mutation analysis and clinical features. However clinical studies have revealed that the pathogenetic mutation that a patient carries in the GALC gene is not always predictive of outcome, and the reasons for such variability are unclear. Therefore, it is difficult to predict the disease course accurately. Unfortunately, the only available therapeutic option is hematopoietic cell transplantation (HCT) before symptoms occur, thus prognostic indicators are of utmost importance for disease management. HCT only partially improves survival and attenuates the disease course in the infantile phenotype, presumably by transfer of GALC from donor cells to myelinating cells of the patients. One unanswered question in Krabbe and other demyelinating disease is whether neurodegeneration is only secondary to demyelination, or if neurons or other brain cells are also direct targets of the disease process. I hypothesize that: 1) In addition to the mutation, cis-polymorphisms also affect the trafficking of GALC to the lysosome which is indispensable for GALC processing and activation, ultimately influencing the phenotype. 2) Any brain cell other than oligodendrocytes can produce toxicity which eventually damages neurons. Two specific aims will test this idea: 1) Identify the effect of the combination of cis-polymorphisms with Galc mutations on GALC trafficking, processing, and activity in the ER, Golgi, and lysosome, 2) Identify the effect of the absence of GALC in each brain cell type on myelination and neurodegeneration. For the first aim, I will test if any of the cis-polymorphisms that have been reported to coexist with certain mutations affects the trafficking of GALC. For the second aim, I will purify each type of brain cell from the twitcher mouse model of Krabbe disease and coculture them in various combinations to elucidate in which cells GALC loss-of-function is important and which cells are the most important target of toxicity in demyelinating neurodegeneration. This approach is innovative because for the first time it considers cell autonomy and the effect of cis- polymorphisms in Krabbe disease. The project will have impact because it will allow us to better understand which factors determine the prognosis of Krabbe patients, and will provide information necessary to design rational and effective therapies.

描述（由申请人提供）：该提案的目标有两个：1）了解为什么半乳糖苷神经酰胺酶（Galc）基因中的相同突变会导致克拉伯脑白质营养不良患者存在大量临床变异，2）了解脑细胞是否除少突胶质细胞外，其他细胞都是 GALC 缺陷的直接目标。这两个问题的答案对于准确诊断和设计更有效的疗法至关重要。这种疾病是由于溶酶体酶 GALC 的常染色体隐性突变引起的，会导致严重的脱髓鞘和神经变性。超过 85% 的 Krabbe 患者表现为婴儿期发病、进行性神经功能恶化，并在两岁时死亡，而其他患者则发病较晚，病情不太严重。该疾病通过测量 GALC 活性进行诊断，并通过突变分析和临床特征进行确认。然而临床研究表明，患者 GALC 基因中携带的致病突变并不总是能预测结果，而且这种变异的原因尚不清楚。因此，很难预测病程准确。不幸的是，唯一可用的治疗选择是在症状出现之前进行造血细胞移植（HCT），因此预后指标对于疾病管理至关重要。 HCT 仅部分提高了婴儿表型的生存率并减轻了病程，推测是通过将 GALC 从供体细胞转移到患者的髓鞘细胞来实现的。克拉伯和其他脱髓鞘疾病中一个尚未解答的问题是，神经变性是否仅继发于脱髓鞘，或者神经元或其他脑细胞是否也是疾病过程的直接目标。我假设：1）除了突变之外，顺式多态性还影响 GALC 向溶酶体的运输，这对于 GALC 加工和激活是必不可少的，最终影响表型。 2）除少突胶质细胞外的任何脑细胞都可以产生毒性，最终损害神经元。两个具体目标将检验这一想法：1) 确定顺式多态性与 Galc 突变的组合对 GALC 在内质网、高尔基体和溶酶体中运输、加工和活性的影响，2) 确定 GALC 缺失的影响每种脑细胞类型对髓鞘形成和神经变性的影响。对于第一个目标，我将测试已报道与某些突变共存的任何顺式多态性是否会影响 GALC 的运输。对于第二个目标，我将从克拉伯病的 twitcher 小鼠模型中纯化每种类型的脑细胞，并将它们以各种组合共培养，以阐明哪些细胞 GALC 功能丧失很重要以及哪些细胞是最重要的毒性目标在脱髓鞘神经变性中。这种方法具有创新性，因为它首次考虑了克拉伯病中细胞自主性和顺式多态性的影响。该项目将产生影响，因为它将使我们更好地了解哪些因素决定克拉布患者的预后，并将提供设计合理有效的疗法所需的信息。