Project 2: Mitochondrial ROS in aging-related skeletal muscle aging

项目总结 之前在这项P01下的工作已经证明，用线粒体靶向多肽的单一治疗 SS-31可改善骨骼肌性能、线粒体功能，并减少氧化还原压力。这些 令人惊讶的结果表明，线粒体功能障碍随着年龄的增长是一个更动态的过程 以前认为的，可以通过晚年治疗来逆转，以提高健康寿命。这一新的范式引领了 直接到华盛顿大学正在进行的由Kevin Conley(PL-Core B)领导的临床试验，测试SS- 31用于改善老年人的骨骼肌功能。本次续订中提供的初步数据 此外，SS-31的短期治疗(4-8周)可以改善心脏和骨骼 老年啮齿动物的肌肉功能和视力。来自我们实验室、Core E和其他机构的其他数据表明，SS- 31不是一种传统的抗氧化剂，通过清除活性氧物种发挥作用。相反，有越来越多的 SS-31与线粒体心磷脂相互作用改善线粒体电子传递系统的证据 (ETS)功能和减少线粒体氧化应激。我们提出了一种改进的ETS函数，该函数具有短路特性。 长期治疗减少氧化还原和能量应激，从而改善老年人的功能和应激反应 肌肉。通过长期治疗，这种改进的应激信号可以恢复线粒体结构，从而导致 线粒体和骨骼肌性能的进一步改善。目标1使用正常老化和ETS 靶向毒素，阿霉素，以测试这一假说逆转年龄相关性肌肉功能障碍。我们 评估SS-31治疗1天、1周和8周对线粒体氧化还原和细胞周期的影响 能量应激、调节线粒体质量的应激信号和骨骼肌性能。简而言之- 术语效应我们将集中于关键应激反应和关键应激反应中的硫醇和磷酸蛋白质组的目标分析 功能通路。我们已经发现，减少线粒体氧化应激可以逆转许多年龄- 与硫醇蛋白质组相关的氧化变化，包括参与肌肉收缩、EC偶联、 蛋白质质量控制和线粒体能量学。AIM 2使用SOD1-/-小鼠测试是否有保护作用 SS-31在这种加速性石棺减少模型中线粒体ETS功能和减轻氧化还原应激 在出现肌肉功能障碍时开始治疗，防止肌肉萎缩。AIM 3在 项目和测试在中年开始的SS-31治疗是否在正常衰老和 高脂肪饮食使衰老变得更加复杂。在项目2中测试的许多机制可能与 老化的心脏(项目1)和视觉系统(项目3)。因此，这三个方面的并行工作 我们已经确定SS-31显著逆转了生理衰退的系统，提供了 识别线粒体功能对衰老基础生物学有贡献的独特机会 跨越不同的生理系统。最终的结果将是对这一新的 改善健康寿命的范例，有可能直接移植到老年人身上。

PROJECT SUMMARY Previous work under this P01 has demonstrated that a single treatment with the mitochondrial targeted peptide SS-31 improves skeletal muscle performance, mitochondrial function, and reduces redox stress. These surprising results demonstrate that mitochondrial dysfunction with age is a more dynamic process than previously thought and can be reversed by late-life treatment to improve healthspan. This new paradigm led directly to an ongoing clinical trial at the University of Washington led by Kevin Conley (PL-Core B) testing SS- 31 for improvement in skeletal muscle function in elderly humans. Preliminary data presented in this renewal also demonstrates that relatively short term treatment (4-8 weeks) with SS-31 can improve cardiac and skeletal muscle function and vision in aged rodents. Additional data from our lab, Core E, and others indicates that SS- 31 does not act as a traditional antioxidant by scavenging reactive oxygen species. Instead there is growing evidence that SS-31 interacts with mitochondrial cardiolipin to improve mitochondrial electron transport system (ETS) function and reduce mitochondrial oxidative stress. We propose that improved ETS function with short- term treatment reduces redox and energy stress which improves function and stress response of the aged muscle. With long-term treatment this improved stress signaling restores mitochondrial structure leading to further improvements in mitochondrial and skeletal muscle performance. Aim 1 uses normal aging and an ETS targeted toxin, doxorubicin, to test this hypothesis for the reversal of age-related muscle dysfunction. We assess the effect of 1 day, 1 week, and 8 week SS-31 treatment on the reversal of mitochondrial redox and energy stress, stress signaling regulating mitochondrial quality, and skeletal muscle performance. For short- term effects we will focus on targeted analyses of the thiol and phospho proteomes in key stress response and functional pathways. We have found that reducing mitochondrial oxidative stress reverses many of the age- related oxidative changes to the thiol proteome, including proteins involved in muscle contraction, EC coupling, protein quality control, and mitochondrial energetics. Aim 2 uses SOD1-/- mice to test whether protection of mitochondrial ETS function and reducing redox stress with SS-31 in this model of accelerated sarcopenia can prevent muscle atrophy when treatment is initiated at the onset of muscle dysfunction. Aim 3 is shared across projects and tests whether SS-31 treatment initiated at mid-life preserves healthspan in normal aging and in aging compounded by high fat diet. Many of the mechanisms tested in Project 2 are likely to be relevant to the aging heart (Project 1) and visual system (Project 3) as well. Therefore the parallel work in these three systems, in which we have already identified significant reversal of physiological decline with SS-31, provides the unique opportunity to identify aspects of mitochondrial function that contribute to the basic biology of aging across diverse physiological systems. The end result will be new insights into the mechanistic basis of this new paradigm for improving healthspan with potential for direct translation to elderly humans.