The Gateway Hypothesis: A new framework for unraveling diverse leukodystrophies

网关假说：解开多种脑白质营养不良的新框架

• 批准号: 8841025
• 负责人: JOHN E RASH
• 金额: $ 39.07万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8841025
• 关键词: Accounting; Action Potentials; Acute; Adult; Astrocytes; Axon; Binding; Biochemical; Biological Assay; Blood capillaries; Brain; Cell Culture Techniques; Cell membrane; Cells; Central Nervous System Diseases; Connexins; Corpus Callosum; Coupled; Coupling; Cytoplasm; Data; Disease; Electrophysiology (science); Exercise; Failure; Functional disorder; Future; Gap Junctions; Giant Cells; Health; Homeostasis; In Vitro; Intervention; Knockout Mice; Knowledge; Lead; Light; Link; Local Anesthetics; Medical; Microscopic; Modeling; Molecular; Monitor; Mus; Mutate; Mutation; Myelin; Nerve Fibers; Oligodendroglia; Optic Nerve; Pathway interactions; Patients; Pharmaceutical Preparations; Physiological; Potassium; Potassium Channel; Process; Production; Proteins; Ranvier' s Nodes; Rattus; Reducing Agents; Replacement Therapy; Research; Resolution; Resources; Rest; Role; Sclerosis; Site; Slice; Sodium Channel; Spinal; Stem cells; Surface; Swelling; Therapeutic Intervention; Water; Work; aquaporin 4; base; capillary; immunocytochemistry; insight; leukodystrophy; novel; novel therapeutic intervention; particle; protein K; repaired; sciatic nerve; spinal cord white matter; stem cell therapy; voltage; voltage gated channel; water channel; white matter; white matter damage

DESCRIPTION (provided by applicant): Previously, there was no conceptual framework for linking the diverse molecular and cellular disruptions seen in the leukodystrophies into a coherent model for the production of the generalized CNS white matter destruction that is the hallmark of these diseases. This lack of a coherent model was particularly problematic for molecular disruptions in astrocytes, which are far removed from the oligodendrocyte myelin that becomes sclerotic. We recently introduced the "Gateway Hypothesis" to account for the widespread destruction of CNS myelin that characterizes these diseases. We proposed that generalized myelin sclerosis is caused by mutation or immunological disruption of proteins comprising the primary transport pathways for K+ and water within and between cells of the panglial syncytium. We and others had identified proteins of the K+ and water transport pathway that, when mutated or destroyed, disrupt ionic homeostasis, primarily because K+ and water continue to enter the panglial syncytium but are blocked before they can exit. The Gateway Hypothesis suggests that pharmacological agents that reduce K+ entry into the panglial syncytium may provide new therapeutic approach to treating these diseases. Two abundant protein molecules of that pathway - KV1 (the voltage-gated channels of myelinated axons) and Cx29 (a poorly-understood oligodendrocyte connexin that does not form gap junctions) - are proposed to represent the "gateway" for entry of water and K+ into the panglial syncytium. As such, these tightly-associated proteins, as well as voltage-gated sodium channels at nodes of Ranvier, are proposed as potential targets for pharmacologic intervention in many of the leukodystrophies. The rationale is that by reducing axonal Na+ influx and/or K+ efflux and its coupled influx into the surrounding myelin, the osmotic burden that causes myelin swelling and sclerosis can be reduced sufficiently to allow undamaged K+ and water transport pathways to redistribute the pharmacologically-reduced osmotic load, thereby permitting normal cellular repair mechanisms to partially restore myelin function, allowing for longer-term treatments, potentially including glial stem cell replacement therapies. We propose to use: 1) ultrastructural and super-resolution light microscopic immunocytochemistry; 2) molecular pull-down assays; 3) expression of Cx29 and KV1 channels in cell culture, with monitoring by intracellular recording electrophysiology; and 4) recording from oligodendrocytes in acute slices of mouse corpus callosum of normal and exercised wildtype and Cx29 knockout mice. We will thus characterize KV1 channels in axon plasma membranes and Cx29 channels in the adjacent innermost layer of myelin and establish functional interaction of those molecules as the K+ "gateway" into the panglial syncytium. With these new data, the Gateway Hypothesis will provide the framework for identifying which of the leukodystrophies are immediately amenable to pharmacologic intervention and/or stem cell therapies, allowing medical resources to be delivered to the patients who can be most effectively treated.

描述（由申请人提供）：以前，没有概念框架可以将白细胞营养不良中的分子和细胞中断连接到一个连贯的模型，用于生产这些疾病的标志，这是这些疾病的标志。缺乏连贯的模型对于星形胶质细胞的分子破坏尤其有问题，星形胶质细胞与少突胶质细胞髓磷脂的去除相去甚远。我们最近引入了“网关假设”，以说明特征这些疾病的CNS髓磷脂的广泛破坏。我们提出，概括性的髓质硬化症是由蛋白质的突变或免疫学破坏构成了蛋白质的蛋白质，该蛋白质包含了panglial合胞体细胞内和细胞之间的主要运输途径。我们和其他人已经确定了K+和水传输途径的蛋白质，这些蛋白质在突变或破坏时会破坏离子稳态，这主要是因为K+和水继续进入panglial synivium，但在它们退出之前被阻止。门户假设表明，减少K+进入panglial合胞体的药理学剂可能会为治疗这些疾病提供新的治疗方法。该途径的两个丰富的蛋白质分子-KV1（髓鞘轴突的电压门控通道）和CX29（一种不形成间隙连接的少突胶质细胞连接蛋白） - 被提议代表水和k+进入panglial synimcytium的“网关”。因此，这些紧密相关的蛋白质以及兰维尔节点处的电压门控通道被提议作为许多白细胞障碍的药物干预的潜在靶标。基本原理是，通过减少轴突Na+流入和/或K+ EFFLUX及其融合到周围的髓磷脂中的耦合，会导致骨髓肿胀和硬化症的渗透负担充分减少，以使其不受损害的K+和水的运输路径，从而使我的渗透率重新分配了允许的正常运行，使其正常地进行了正常工作，使其正常地进行了正常工作，使其正常地进行了工作，使其正常地进行了兼容的正常工作，允许长期治疗，可能包括神经胶质干细胞替代疗法。我们建议使用：1）超微结构和超分辨率光显微镜免疫细胞化学； 2）分子下拉测定； 3）CX29和KV1通道在细胞培养中的表达，并通过细胞内记录电生理学进行监测； 4）在急性切片的急性切片中记录了正常和锻炼的野生型和CX29敲除小鼠的急性切片。因此，我们将表征在髓磷脂的相邻最内层的轴突质膜和CX29通道中的KV1通道，并将这些分子的功能相互作用作为K+“ Gateway”建立在panglial syncytium中。有了这些新数据，门户假设将提供框架，以识别哪些白细胞营养不良物立即与药物干预和/或干细胞疗法相融合，从而可以将医疗资源交付给可以最有效治疗的患者。