Somatic mtDNA mutations in brain aging: a single-cell approach

描述（由申请人提供）：这是对母授权R 01 AG 019787的竞争性修订请求，以响应通知编号（NOT-OD-09-058）：NIH宣布恢复法案资金可用于竞争性修订。母申请的目标是研究与年龄相关的退行性过程的机制，特别是测试线粒体DNA（mtDNA）突变参与衰老过程，特别是大脑衰老的假设。母公司的提案特别关注线粒体DNA缺失，即从线粒体基因组中去除大的DNA片段导致的突变。这些突变涉及许多遗传性退行性线粒体疾病，并被假设在大脑，肌肉和其他组织的衰老中发挥作用。导致mtDNA缺失的过程受到了深入的研究，但仍然是一个有争议的问题。父母补助金的一个局限性是缺乏对mtDNA突变来源的研究。由母基金资助的工作允许建立几个所谓的mtDNA缺失突变谱，即缺失片段沿线粒体基因组沿着的位置分布。这项工作暗示，不同类型的样本之间的mtDNA缺失突变谱不同，这意味着不同类型的样本中的缺失可能是由不同的机制产生的。这一修订将追求两个具体目标。首先，将开发有效研究突变谱所需的技术，并用于确认突变谱之间差异的初步发现。第二，老年脑组织的突变谱与一组样本的谱进行比较，这些样本携带mtDNA代谢、线粒体动力学或受到氧化应激的特定缺陷，将用于测试关于人类衰老和疾病中mtDNA缺失来源的各种假设。 公共卫生相关性：特别是大脑的老化和老化给社会带来了越来越大的负担，然而，导致大脑恶化变化的分子机制却知之甚少。这一修订旨在确定线粒体DNA缺失的来源，这些缺失越来越多地与衰老过程有关。

DESCRIPTION (provided by applicant): This is a request competitive revision of the parent grant R01 AG019787 in response to Notice Number (NOT-OD-09-058): NIH Announces the Availability of Recovery Act Funds for Competitive Revision. The goal of the parent application is to study mechanisms responsible for age-related degenerative processes and in particular, to test the hypothesis that mutations in mitochondrial DNA (mtDNA) are involved in the aging process, especially in brain aging. The parent proposal is particularly focused on mtDNA deletions, i.e. mutations resulting from removal of large DNA segments from the mitochondrial genome. These mutations are involved in a number of inherited degenerative mitochondrial diseases and have been hypothesized to play a role in the aging of brain, muscle and potentially other tissues. The processes that result in the generation of deletions in mtDNA are subject to intense research, but remain a matter of debate. A limitation of the parent grant is the lack of studies of the sources of mtDNA mutations. Work encompassed by the parent grant permitted to build several so-called mutational profiles of mtDNA deletions, i.e. the distributions of the positions of the deleted segments along the mitochondrial genome. This work hinted that mutational profiles of mtDNA deletions differ between different types of samples, which imply that deletions in different types of samples may be generated by different mechanisms. This revision will pursue two specific aims. First, the technology necessary for efficient studies of mutational profiles will be developed and used to confirm the preliminary finding of the differences among mutational profiles. Second, comparison of mutational profiles of aged brain tissue with profiles of a panel of samples that carry specific defects in mtDNA metabolism, mitochondrial dynamics or are subjected to oxidative stress will be used to test various hypotheses regarding the sources of mtDNA deletions in human aging and disease. PUBLIC HEALTH RELEVANCE: Aging and aging of the brain in particular imposes increasing burden on the society, however, molecular mechanisms leading to deteriorative changes in the brain are poorly understood. This revision seeks to determine the sources of deletions in mitochondrial DNA that are increasingly implicated in the aging process.