Linking mitochondrial variation and lifespan amongst five species of Rodentia

 描述（由申请人提供）：即使在密切相关的物种之间，寿命也有很大差异，如灵长类动物和啮齿类动物。尽管存在这些寿命差异，但最近的研究主要集中在特定的衰老病理学上，主要是 在鼠系统中。虽然老鼠已经为衰老生物学提供了很多见解，但尚不清楚这种短命物种是否缺乏可能在相关长寿物种中进化出来的抗衰老防御能力。许多与年龄相关的疾病都与线粒体功能障碍有关，线粒体功能障碍可以通过能量产生减少、细胞成分结构损伤甚至细胞死亡来衡量。翻译后修饰（PTMs）协调了许多与细胞代谢相关的途径，并被认为是生物衰老的关键调节因子。超乙酰化是一种这样的修饰，其涉及影响能量代谢的许多线粒体损伤。最近，我们观察到由于sirtuin 3（SIRT 3）敲除和通过热量限制提高SIRT 3表达（这两个因素都影响蛋白质乙酰化状态）而导致的与氧化磷酸化相关的途径中的蛋白质/酶的显著超乙酰化。此外，热量限制和SIRT 3表达显著增加了小鼠肌肉中通过电子传递系统（ETS）复合物I和II的电子通量，表明乙酰化状态在线粒体呼吸中起着关键作用。在比较物种之间的差异时，将小鼠与长寿裸鼹鼠进行比较的初步工作揭示了ETS范围内的差异，例如裸鼹鼠大脑和心脏中的漏呼吸和复合IV活动较低，表明线粒体代谢存在固有差异。在这里，我们的目标是建立是否hyperacetylation与线粒体功能障碍和小鼠之间的寿命差异，大鼠，13线地松鼠，灰松鼠和裸鼹鼠。我们将使用高分辨率呼吸测定法测量所有五个物种的肌肉和肝脏中通过ETS的流量，并通过测量孤立的复杂活动来证实这些测量。接下来，我们将量化这些样本中肽乙酰化的化学计量，以确定它们是否与线粒体功能和寿命相关。本文提出的研究将阐明乙酰化在调节衰老中的进化作用，并建立潜在的靶点，以及验证现有的治疗干预靶点。R 03小赠款机制非常适合所提出的工作，因为它很好地与我们正在进行的小鼠模型衰老研究相结合，并利用我们最近开发的方法来确定大型蛋白质组中乙酰化的位点特异性化学计量。

 DESCRIPTION (provided by applicant): Lifespan varies dramatically among even closely related species, as exemplified within groups such as primates and rodents. Despite these disparities in lifespan, recent studies have focused on intra-specific aging pathologies, primarily within the murine system. While mice have provided much insight into aging biology, it is unclear if such a short-lived species lack defenses against senescence that may have evolved in related long- lived species. Many age-related diseases have been linked to mitochondrial dysfunction that are measured by decreased energy generation, structural damage to cellular components, and even cell death. Post translational modifications (PTMs) orchestrate many of the pathways associated with cellular metabolism, and are thought to be a key regulator in biological senescence. Hyperacetylation is one such modification that has been implicated in numerous mitochondrial impairments affecting energy metabolism. Recently, we observed significant hyperacetylation of proteins/enzymes in pathways associated with oxidative phosphorylation due to sirtuin 3 (SIRT3) knockout and elevated SIRT3 expression via caloric restriction - both factors that influence protein acetyl status. Furthermore, caloric restriction ad SIRT3 expression significantly increased electron flux through both complex I and II of the electron transport system (ETS) in muscle of mice, suggesting acetylation status plays a critical role in mitochondrial respiration. When comparing differences between species, preliminary work comparing mice to the long-lived naked mole rat revealed ETS-wide differences, such as lower leak respiration and complex IV activities in the brain and heart of naked mole rats, indicating inherent differences in mitochondrial metabolism. Here, we aim to establish whether hyperacetylation is associated with mitochondrial dysfunction and differences in lifespan between mice, rats, thirteen-lined ground squirrels, grey squirrels and naked mole rats. We will measure flux through the ETS in the muscle and liver of all five species using high-resolution respirometry and substantiate these measurements by measuring isolated complex activities. Next, we will quantify the stoichiometry of peptide acetylation from these samples to determine if they are correlated with both mitochondrial function and lifespan. The research proposed here will elucidate the evolutionary role of acetylation in regulating aging, and establish potential targets as well as validate existing targets for therapeutic interventions. The R03 small-grant mechanism is an excellent fit for the proposed work, as it nicely piggybacks with our ongoing aging studies in the murine model and takes advantage of our recently developed methods to determine site-specific stoichiometry of acetylation in a large proteome.