Adaptive Physiology of mtDNA Longevity Mutations

描述（由申请人提供）：对欧亚大陆百岁老人的几项调查显示，特定的线粒体DNA （mtDNA）谱系与神经退行性疾病的减少和寿命的延长有关。这些相同的欧亚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，这使得这些谱系的创始人能够适应越来越冷的气候，因为他们从非洲迁移到欧亚大陆，然后进入西伯利亚和北美。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，因为它们部分地使线粒体氧化磷酸化（OXPHOS）失偶。这增加了热量的产生，但它对衰老有保护作用，因为它保持了电子传递链的氧化，从而减少了线粒体活性氧（ROS）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的mtDNA是否在他们从北极向南迁移到热带南美的过程中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评估骨骼肌线粒体OXPHOS酶水平与mtDNA单倍群的关系，并将生化缺陷与肌肉能量学的改变联系起来。然后将不同的mtDNA单倍群转移到相同的？o淋巴母细胞样细胞核背景，并测试由此产生的杂交体在线粒体酶、OXPHOS偶联、ROS产生、线粒体和细胞氧化损伤、线粒体通透性过渡孔（mtPTP）的超激活以及MITOCHIP基因表达谱的变化方面的差异。我们将确定体细胞mtDNA控制区（CR）和重排突变在不同气候适应突变的受试者细胞和组织中积累的程度。最后，我们将对适应极端气候的小鼠的mtdna进行测序。如果它们也有适应性mtDNA突变，那么使用雌性胚胎干细胞系将变异mtDNA谱系引入小鼠生殖系。这些小鼠的后代将被用来测试它们对冷热的敏感性、线粒体的生物化学和生理学、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.