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性疾病通常是多系统性的，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，很难理解与此类疾病相关的致病过程，更不用说开发治疗方法了。近年来，我们已经成功地使用基因治疗的工具，即病毒介导的核酶转移，来创建具有许多线粒体疾病的共同特征的动物模型-视神经变性。对线粒体呼吸链的复合物I的核编码亚基（NDUFA 1）特异的核酶导致类似于在Leber遗传性视神经病变（最常见的遗传性线粒体疾病）中所见的损伤。我们最近已经证明了类似的病理学使用核酶靶向另一个亚基（ND 4）的相同的酶是在线粒体内产生的。在这项提案中，我们计划开发小鼠模型，捕获另一种称为NARP的线粒体疾病，并迈出基因治疗这些毁灭性疾病的第一步。我们建议：（1）开发可递送至线粒体的核酶以产生线粒体ATP合酶（复合物V）的ATP 6亚基缺陷的小鼠模型;和（2）通过递送替换缺陷的线粒体基因产物的核基因（称为异位表达的程序）来治疗通过核酶敲减ATP 6和ND 4而开发的动物模型。由于已经确定同素异形体表达可以挽救培养细胞中的线粒体缺陷，因此我们的第二个目标独立于第一个目标：重要的是要测试线粒体疾病中通常受影响的动物组织中的异位表达。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特定假设，但我们的最终目标是开发线粒体疾病的治疗方法-无论是遗传还是药物。

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 tools 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.