Adaptive Physiology of mtDNA Longevity Mutations

描述(申请人提供)：几项对欧亚大陆百岁老人的调查显示，特定的线粒体DNA(MtDNA)谱系与减少神经退行性疾病和延长寿命有关。这些相同的欧亚大陆mtDNA谱系(单倍群)显示出惊人的区域定位，我们最近发现，这是mtDNA错义突变的结果，这些谱系的创始人在从非洲迁徙到欧亚大陆，然后迁徙到西伯利亚和北美时，能够适应日益寒冷的气候。我们假设错义突变对神经退行性疾病和衰老具有保护作用，因为它们部分解偶联线粒体氧化磷酸化(OXPHOS)。这增加了产热，但它对衰老具有保护作用，因为它保持电子传输链的氧化，从而减少线粒体活性氧(ROS)物种的产生和氧化损伤。为了验证这一假设，我们建议确定美洲原住民线粒体DNA在从北极向南迁移到热带南美洲时是否获得了新的适应性突变。我们还将通过磁共振和近红外光谱分析，将骨骼肌线粒体OXPHOS酶水平与mtDNA单倍群相关联，并将生化缺陷与肌肉能量学变化相关联。然后将不同的mtDNA单倍群转移到相同的淋巴母细胞核背景中，并检测得到的胞质在线粒体酶、OXPHOS偶联、ROS产生、线粒体和细胞氧化损伤、线粒体通透性转换孔(MtPTP)的过度激活以及MITOCHIP基因表达谱的变化方面的差异。我们将确定具有不同气候适应突变的受试者细胞和组织中积累的体细胞线粒体DNA控制区(CR)和重排突变的程度。最后，我们将对适应极端气候的小鼠的线粒体DNA进行测序。如果他们也有适应性的mtDNA突变，那么使用雌性ES细胞系将变异的mtDNA谱系引入小鼠生殖系。这些小鼠将被培育出后代，测试它们对热和冷的敏感性、线粒体的生化和生理学、运动生理学和寿命。

DESCRIPTION (provided by applicant): Several surveys of centenarians from Eurasia have revealed that specific mitochondrial DNA (mtDNA) lineages are associated with reduced neurodegenerative disease and increased longevity. These same Eurasia mtDNA lineages (haplogroups) show striking regional localization which we have recently discovered is the result of mtDNA missense mutations that permitted the founders of these lineages to adapt to the increasingly colder climates as they migrated out of Africa into Eurasia and then into Siberia and North America. We hypothesize that missense mutations are protective of neurodegenerative diseases and aging because they partially uncouple mitochondrial oxidative phosporylation (OXPHOS). This increased heat production, but it is protective of aging because it keeps the electron transport chain oxidized thus reducing mitochondrial reactive oxygen (ROS) species production and oxidative damage. To test this hypothesis, we propose to determine if Native American mtDNA acquired new adaptive mutations as they migrated southward from the arctic to tropical South America. We will also correlate skeletal muscle mitochondrial OXPHOS enzyme levels with mtDNA haplogroups and correlate the biochemical defects with alterations in muscle energetics as assessed by magnetic resonance and Near Infra-red spectroscopy. Then transfer the various mtDNA haplogroups into the same ?o lymphoblastoid cell nuclear background and test the resulting cybrids for differences in mitochondrial enzymes, OXPHOS coupling, ROS production, mitochondrial and cellular oxidative damage, hyper-activation of the mitochondrial permeability transition pore (mtPTP) and changes in MITOCHIP gene expression profile. We will determine the extent of somatic mtDNA control region (CR) and rearrangement mutations that accumulate in the cells and tissues of subjects with different climatic adaptive mutations. Finally, we will sequence the mtDNAs of mice that have adapted to climatic extremes. If they also harbor adaptive mtDNA mutations, then use female ES cell line to introduce the variant mtDNA lineages into the mouse germ line. These mice will be bred the progeny tested for their sensitivity to heat and cold, the biochemistry and physiology of their mitochondria, their exercise physiology, and their longevity.