Targeting mitochondrial gene expression in the retina

描述（由申请人提供）：与线粒体DNA突变相关的母系遗传疾病通常是多系统的，通常影响中枢神经系统、心脏、骨骼肌和内分泌腺。由于缺乏概括线粒体疾病特征的动物模型，很难理解与这些疾病相关的致病过程，更不用说开发治疗方法了。近年来，我们已经成功地利用基因治疗的基础，即病毒介导的核酶转移，建立了具有许多线粒体疾病共同特征的动物模型-视神经变性。线粒体呼吸链复合体I核编码亚基（NDUFA1）特异性的核酶导致的损伤与最常见的遗传性线粒体疾病Leber遗传性视神经病变类似。我们最近已经证明了类似的病理，使用针对线粒体内产生的同一酶的另一个亚基（ND4）的核酶。在这项提案中，我们计划开发捕获另一种称为NARP的线粒体疾病的小鼠模型，并向这些毁灭性疾病的基因治疗迈出第一步。我们建议：(1)开发可以传递到线粒体的核酶，以创建线粒体ATP合酶（复合物V）的ATP6亚基缺陷的小鼠模型；(2)通过传递替代缺陷线粒体基因产物的核基因（称为异位表达）来治疗由核酶敲低ATP6和ND4形成的动物模型。由于已经确定同种异体表达可以挽救培养细胞中的线粒体缺陷，我们的第二个目标独立于第一个目标：在线粒体疾病中通常受到影响的动物组织中测试同种异体表达是很重要的。虽然我们正在测试关于线粒体损伤如何导致视网膜病变和视神经病变的具体假设，但我们的最终目标是开发线粒体疾病的治疗方法——无论是基因还是药物。

DESCRIPTION (provided by applicant): Maternally inherited diseases associated with mutations in mitochondrial DNA are generally multisystemic, typically affecting the central nervous system, heart, skeletal muscles and endocrine glands. It has been difficult to understand the pathogenic processes associated with such disorders, much less to develop treatments, because of the lack of animal models that recapitulate the characteristics of mitochondrial disease. In recent years, we have succeeded in using the toots of gene therapy, namely the viral-mediated transfer of ribozymes, to create animal models with a common feature of many mitochondrial diseases - optic nerve degeneration. Ribozymes specific for a nucleus-encoded subunit (NDUFA1) of Complex I of the mitochondrial respiratory chain lead to damage similar to that seen in Leber Hereditary Optic Neuropathy, the most common inherited mitochondrial disease. We have recently demonstrated similar pathology using a ribozyme targeted to another subunit (ND4) of the same enzyme that is produced within mitochondria. In this proposal, we plan to develop mouse models that capture another mitochondrial disorder called NARP and to take the first steps toward gene therapy of these devastating diseases. We propose: (1) To develop ribozymes that can be delivered to mitochondria to create mouse models with deficits in the ATP6 subunit of the mitochondrial ATP synthase (Complex V); and (2) To treat the animal models developed by ribozyme knockdown of ATP6 and ND4 by delivering nuclear genes that replace the deficient mitochondrial gene product, a procedure termed allotopic expression. Since it has already been established that allotropic expression can rescue mitochondrial defects in cultured cells, our second aim stands independently of the first: It is important to test allotopic expression in animal tissues that are typically affected in mitochondrial disease. While we are testing specific hypotheses concerning how mitochondrial damage causes retinopathy and optic neuropathy, our ultimate aim is developing treatments - either genetic or pharmacological - for mitochondrial disease.