Generation of a mouse model of episodic ataxia type 2 (EA2)

2 型发作性共济失调 (EA2) 小鼠模型的生成

• 批准号: 7313608
• 负责人: ELLEN J. HESS
• 金额: $ 17.94万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-04 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7313608
• 关键词: Address; Animal Model; Ataxia; Behavioral; Biological Models; Caffeine; Calcium Channel; Chemicals; Chromosome Mapping; Class; Complex; Development; Disease; Dominant-Negative Mutation; Dyskinetic syndrome; Emotional Stress; Epilepsy; Ethanol; Etiology; Exercise; Functional disorder; Generations; Genes; Genetic Predisposition to Disease; Human; In Vitro; Individual; Ion Channel; Ions; Migraine; Modeling; Mus; Mutant Strains Mice; Mutation; Neurobiology; Neurologic; Neurologic Dysfunctions; Neurons; Outcome; P-Q type voltage-dependent calcium channel; Paralysed; Pathogenesis; Pharmacotherapy; Phenotype; Physiological; Positioning Attribute; Process; Property; Risk; Symptoms; System; Testing; Work; base; behavior test; experience; human disease; in vivo; insight; mouse model; mutant; nervous system disorder; psychologic; research study; stressor; tool; voltage

DESCRIPTION (provided by applicant): Episodic neurological disorders are characterized by attacks of debilitating symptoms interspersed with periods of relatively normal function. Although the symptoms can be diverse, including migraine headache, epilepsy, paralysis, ataxia, and dyskinesia, there are marked similarities in both the genetic etiology and the factors capable of triggering attacks in episodic disorders. Many episodic disorders are associated with ion channel mutations. Further, regardless of the class of ion channelopathy or the expressed symptoms, the precipitants of attacks are most commonly psychological, physical or chemical stressors, suggesting the existence of a common mechanism for the initiation of the attacks. There is little understanding of the mechanisms by which these triggers precipitate neurological dysfunction in individuals who are otherwise normal between attacks. Our approach to this problem is to use a rare monogenic disorder as a model system. because understanding pathogenesis in a monogenic episodic disorder will likely provide insight into genetically complex episodic disorders such as migraine headache and idiopathic epilepsy. We have identified episodic ataxia type 2 (EA2), as a leading candidate for modeling this class of disorders in mice. EA2 is caused by mutations in the CACNA1A gene, which encodes the pore-forming a12.1 subunit of Cav2.1 (P/Q-type) voltage-gated calcium channels. This disorder is particularly amenable for modeling because there is already a wealth of basic information on which to build, including an enormous body of work describing normal and mutant Cav2.1 channel properties in vitro. Individuals with episodic ataxia type 2 experience paroxysmal attacks of migraine, ataxia, and other neurological signs that are triggered by emotional stress, exercise, caffeine or ethanol. Although the mutations in CACNA1A were first identified in 1996, the pathogenic mechanisms are still unknown. Functional expression studies of EA2 mutations in heterologous systems demonstrate reduced Cav2.1 currents, as expected. However, there is evidence for both haploinsufficiency and dominant negative effects of the mutant channel, demonstrating that even this most basic of questions requires expression of the mutants in a native in vivo system. Work in both cultured neurons and mouse mutants also demonstrates that an appreciation of the biophysical properties of the mutant channel in vitro is not likely to provide a comprehensive understanding of the phenotype because compensatory processes in neurons in vivo may also contribute. These results demonstrate the need for a behaviorally intact animal model to fully appreciate disease processes. Therefore, we will develop and characterize a knockin mouse bearing an EA2 mutation. The specific aims of this proposal are 1) To develop and characterize a knockin mouse model of EA2. 2) To behaviorally characterize the EA2 knockin mice. The development of a mouse model will place us in an excellent position to examine pathophysiology and provide insight into human disease. Episodic neurological disorders are characterized by attacks of debilitating symptoms, including migraine headache, epilepsy, paralysis, ataxia, and dyskinesia, interspersed with periods of relatively normal function. There is little understanding of the pathophysiological mechanisms that triggers neurological dysfunction. Therefore, we will develop and characterize a knockin mouse bearing a human mutation for episodic ataxia, a rare monogenic disorder that may provide insight into genetically complex episodic disorders such as migraine headache and idiopathic epilepsy.

描述（由申请人提供）：情节神经系统疾病的特征是散布在功能相对正常的时期的使人衰弱的症状发作。尽管这些症状可能会多种多样，包括偏头痛，癫痫，瘫痪，共济失调和运动障碍，但遗传病因和能够触发发作性疾病攻击的因素都有明显的相似性。许多发作性疾病与离子通道突变有关。此外，不管离子通道病或表达的症状的类别如何，攻击的降水物最常见的是心理，物理或化学压力源，这表明存在启动攻击的共同机制。对这些触发因素在攻击之间正常的个体中导致神经功能障碍的机制几乎没有理解。我们解决这个问题的方法是将罕见的单基因疾病用作模型系统。因为了解单基因发作疾病中的发病机理可能会洞悉遗传复杂的发作性疾病，例如偏头痛和特发性癫痫。我们已经确定了偶发性共济失调2型（EA2），是对小鼠中这种疾病进行建模的领先候选者。 EA2是由CACNA1A基因突变引起的，该突变编码Cav2.1（P/Q-Type）电压门控钙通道的孔形成A12.1亚基。这种疾病尤其适合建模，因为已经有大量的基本信息可以建立，其中包括描述正常和突变体CAV2.1通道特​​性的大量工作。 2型性共济失调的个体经历了偏头痛，共济失调的阵发性发作，以及其他由情绪压力，运动，咖啡因或乙醇引发的神经系统迹象。尽管Cacna1a中的突变首次在1996年鉴定出来，但病原机制仍然未知。 EA2突变在异源系统中的功能表达研究表明，如预期的那样，CAV2.1电流降低。但是，有证据表明突变通道的单倍弥补和主要的负面影响，表明即使是最基本的问题也需要在体内天然体内表达突变体。在培养的神经元和小鼠突变体中的工作还表明，体外对突变体通道的生物物理特性的欣赏不太可能提供对表型的全面理解，因为体内神经元的补偿过程也可能有助于。这些结果表明，需要行为完整的动物模型以充分欣赏疾病过程。因此，我们将发展并表征具有EA2突变的敲击小鼠。该提案的具体目的是1）开发和表征EA2的敲蛋白小鼠模型。 2）在行为上表征EA2敲击蛋白小鼠。小鼠模型的发展将使我们处于检查病理生理学并提供对人类疾病的洞察力的绝佳位置。情节性神经系统疾病的特征是衰弱的症状发作，包括偏头痛，癫痫，瘫痪，共济失调和运动障碍，并散布在功能相对正常的时期。对触发神经功能障碍的病理生理机制几乎没有理解。因此，我们将开发并表征具有人类突变性共济失调的敲击小鼠，这是一种罕见的单基因疾病，可以洞悉遗传复杂的发作性疾病，例如偏头痛和特发性癫痫。