Treatment for Dysmyelination in PMD and SPG2

PMD 和 SPG2 髓鞘脱失的治疗

基本信息

批准号：
8492191
负责人：
Pamela E Knapp
金额：
$ 18.12万
依托单位：
VIRGINIA COMMONWEALTH UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-01 至 2015-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8492191
关键词：
3&apos Splice Site Animal Model Anti-Inflammatory Agents Behavioral Binding Biochemical Biological Blood - brain barrier anatomy Blood Vessels Brain Breathing CNS degeneration Cells Central Nervous System Diseases Cerebellum Cessation of life Code Cognitive deficits Coupled Coupling Data Defect Development Disease Disease model Dominant-Negative Mutation Dose Dystonia Engineered Gene Epitopes Exons Face Family Gene Deletion Gene Duplication Gene Proteins Gene Silencing Genes Human Impairment In Vitro Individual Injection of therapeutic agent Introns Jimpy Mice Label Life Link Longevity MIP gene Membrane Methods Missense Mutation Modeling Morphology Motor Mus Muscle hypotonia Mutation Myelin Myelin Proteins Neuraxis Neurologic Neurologic Symptoms Nucleic Acid Binding Oligodendroglia Outcome Outcome Measure Palliative Care Pathologic Nystagmus Patients Pelizaeus-Merzbacher Disease Penetration Peptides Peripheral Pilot Projects Point Mutation Poly A Principal Investigator Production Proteins Proteolipids Quality of life RNA Splicing Rabies virus Sensory Severities Severity of illness Small Interfering RNA Solid Spastic Paraplegia Spinal Cord Symptoms Syndrome Tail Testing Therapeutic Time Transgenic Mice Treatment Efficacy Variant Veins Venous Work base behavior test clinically relevant combinatorial design developmental disease dysmyelination early experience efficacy testing feeding gain of function mutation grasp high risk in vitro testing in vivo indexing leukodystrophy meetings mutant neuropathology neurotropic novel novel strategies novel therapeutics programs rabies virus glycoprotein G research study treatment effect treatment strategy

项目摘要

DESCRIPTION (provided by applicant): The proposed studies test the efficacy of an in vivo, therapeutic, silencing strategy for dysmyelinating leukodystrophies that result from production of abnormal proteolipid protein (PLP). Our approach resolves the practical problem of blood brain barrier access, which has been a major obstacle to silencing therapies for CNS diseases. The PLP1 gene codes for both PLP, the major intrinsic CNS myelin protein, as well as the less abundant DM20 protein. The gene is almost 100% conserved across mammalian species, and PLP1 mutations in humans result in a spectrum of relatively rare, X-linked disorders ranging in severity from extreme forms of Pelizaeus-Merzbacher Disease (PMD), a developmental disorder in which the CNS can be essentially devoid of myelin, to milder forms of an allelic condition, Spastic Paraplegia 2 (SPG2). In 60% of cases, PMD is due to gene duplications that result in overproduction of PLP/DM20. The most severe forms of PMD are associated with missense mutations in introns or exons of the PLP1 gene. Interestingly, complete gene deletion results in a milder neurologic impairment. The biological basis of PMD/SPG2 dysmyelination is still not completely understood. PMD patients experience early nystagmus, dystonia, and fail to meet developmental motor milestones. In severe cases, this progresses to hypotonia, difficulty with breathing and feeding, and death. There is no palliative therapy or cure. We reversed certain PLP-related cell defects in culture studies using gene silencing. Based on that work, we pioneered an in vivo PLP-silencing strategy using normal mice. A poly-arginated form of a rabies virus glycoprotein recognition epitope peptide was used to bind and deliver PLP-siRNA to the CNS after peripheral vascular injection. This non-infectious and non-pathogenic strategy enables abundant CNS entry and delivery to specific cells, accompanied by dramatic reductions in normal PLP in both brain and spinal cord. Proposed studies use bona fide murine models of two major mutations causing human PMD to test the efficacy of siRNA on clinically relevant outcomes. Aim 1 studies optimize siRNA treatment parameters in transgenic mice that over-express normal PLP, assessing effects on longevity, and using behavioral (rotarod, grip strength) and histological/biochemical outcome measures. In Aim 2, similar studies are conducted using siRNAs appropriate for jimpy mice, which have a naturally occurring point mutation that codes for a mutant PLP. These proof of concept studies are comprehensive in that they test a similar strategy in well-characterized models of two major forms of PMD. Based on proof of efficacy, we intend to conduct studies that develop PLP-siRNA therapeutics for patients with PMD/SPG2. Further, the strategy of silencing developed here should be applicable to other diseases involving dominant, negative mutations.

描述（由申请人提供）：拟议的研究测试了由异常蛋白质蛋白质（PLP）产生的体内，治疗性，沉默，沉默，沉默策略的功效。我们的方法解决了血脑屏障进入的实际问题，这一直是沉默中枢神经系统疾病疗法的主要障碍。 PLP1基因代码均为PLP，即主要的内在CNS髓磷脂蛋白以及较少丰富的DM20蛋白。 The gene is almost 100% conserved across mammalian species, and PLP1 mutations in humans result in a spectrum of relatively rare, X-linked disorders ranging in severity from extreme forms of Pelizaeus-Merzbacher Disease (PMD), a developmental disorder in which the CNS can be essentially devoid of myelin, to milder forms of an allelic condition, Spastic Paraplegia 2 (SPG2).在60％的情况下，PMD是由于基因复制导致PLP/DM20的过量生产。 PMD的最严重形式与PLP1基因内含子或外显子中的错义突变有关。有趣的是，完整的基因缺失会导致神经系统障碍。 PMD/SPG2炎性差的生物学基础仍然尚不完全了解。 PMD患者经历了早期的眼球震颤，肌张力障碍，并且无法达到发展性运动里程碑。在严重的情况下，这会发展为低位症，呼吸和进食的困难以及死亡。没有姑息治疗或治愈。我们使用基因沉默逆转了培养研究中某些与PLP相关的细胞缺陷。基于这项工作，我们使用正常小鼠开创了一种体内PLP分解策略。狂犬病病毒糖蛋白识别表位肽的多裂纹形式用于在周围血管注射后与CNS结合并输送PLP-SIRNA。这种非感染和非致病策略可以使大量的中枢神经系统进入并传递到特定细胞，并伴随着大脑和脊髓的正常PLP的急剧减少。拟议的研究使用两个主要突变的善意鼠模型，导致人PMD测试siRNA对临床相关结果的功效。 AIM 1研究优化了过表达正常PLP的转基因小鼠中的siRNA处理参数，评估对寿命的影响，并使用行为（rotarod，抓地力）和组织学/生化结果指标。在AIM 2中，使用适用于吉普小鼠的siRNA进行类似的研究，后者具有自然存在的点突变，该突变代码为突变体PLP。这些概念研究证明是全面的，因为它们在两种主要形式的PMD模型中测试了类似的策略。根据功效证明，我们打算进行研究，以开发PMD/SPG2患者的PLP-SIRNA疗法。此外，这里制定的沉默策略应适用于其他涉及主导，负突变的疾病。