Molecular Remedy of Mitochondrial Defects

描述（由申请人提供）：本资助的总体目标是寻求由线粒体氧化磷酸化系统缺陷引起的疾病的分子治疗方法。复合体I是组成氧化磷酸化系统的五个酶复合体中的第一个。它具有最复杂的结构，有45个不同的亚基（其中7个亚基是线粒体编码的（指定为ND1-6和4L）），一个FMN和8个铁硫簇作为辅因子。复合体I缺陷与许多人类线粒体疾病有关。Leber's遗传性视神经病变（LHON）是公认的多发病的复合体I疾病。一种新的动物模型已经被开发，涉及到鱼藤酮生物珠输注到大鼠脑上丘。在动物中观察到典型的LHON症状，最明显的是视力严重受损。同时，RGC轴突有明显的脱髓鞘和Ranvier结的紊乱。然而，视力丧失并不伴随着LHON的特征，如视网膜神经节细胞（RGC）层变薄和RGC死亡，这只发生在后期。此外，将酵母替代NADH脱氢酶基因（NDI1）注入大鼠大脑后，大鼠的视力恢复到正常水平，并伴有Ranvier淋巴结的重组和RGC轴突的髓鞘再生。这些发现构成了这个研究项目的基础。在此资助期内，将重点进行LHON研究，具体目标如下：(i)采用大鼠模型，将突变的人或大鼠ND4基因注入视网膜或鱼藤酮生物珠滴入上丘，探讨LHON的机制。（ii）阐明NDI1基因表达是否可以修复两种LHON模型的视力丧失，确定修复窗口期。（iii）构建携带突变的人或小鼠ND4基因的转基因小鼠品系，进一步研究LHON的触发因素等。

DESCRIPTION (provided by applicant): The overall goal of this grant is to seek molecular therapies for diseases resulting from defects of the mitochondrial oxidative phosphorylation system. Complex I is the first of five enzyme complexes that comprise the oxidative phosphorylation system. It has the most intricate structure with 45 different subunits (of these, 7 subunits are mitochondrially encoded (designated ND1-6 and 4L)), one FMN and eight iron- sulfur clusters as cofactors. Complex I defects are involved in many human mitochondrial diseases. Leber's hereditary optic neuropathy (LHON) is recognized as the frequently occurring complex I disease. A new animal model has been developed that involves infusion of rotenone-biobeads into the superior colliculus of the rat brain. Symptoms typical of LHON were observed in the animals, most notably, severely impaired vision. At the same time, there was clearly disorganization of the node of Ranvier as well as demyelination of the RGC axons. However, loss of vision was not accompanied by the hallmarks of LHON such as thinner retinal ganglion cell (RGC) layer and death of RGC which only occurred at a later stage. Furthermore, delivery of the yeast alternative NADH dehydrogenase gene (NDI1) into the rat brain restored the vision to normal level with concomitant reorganization of the node of Ranvier and remyelination of the RGC axons. These findings form the basis of this research project. During this grant term, focus will be made on LHON research with the following specific aims. (i) To investigate mechanism of LHON by using the rat models by administration of mutated human or rat ND4 gene to the retina or rotenone biobeads infusion in the superior colliculus. (ii) To clarify whether the NDI1 gene expression can repair vision loss of the two LHON models and to determine repair window. (iii) To construct transgenic mouse strains carrying the mutated human or mouse ND4 gene for further investigation of LHON such as triggering factors.