Mitochondrial ATP Synthase Dysfunction and Synaptic Stress in Alzheimer's Disease

项目主任/首席调查员(末位、第一位、中位)：杜恒 项目总结： 越来越多的证据表明，线粒体功能障碍在慢性阻塞性肺疾病的发病机制中起核心作用。 阿尔茨海默病(AD)。突触线粒体产生三磷酸腺苷和钙的能力受损 在富含β的环境中，保留被认为是早期突触损伤的基础。然而，详细的 这种Aβ增强的突触线粒体缺陷的分子机制仍然不清楚。具体的 这项拟议研究背后的假设是，线粒体F1Fo ATP合成酶功能障碍是由寡霉素引起的 敏感性相关蛋白(OSCP)异常是突触线粒体缺陷的潜在原因，导致 与AD相关情况下的突触故障有关。这一假设牢固地建立在以下观察结果之上：第一， 线粒体F1Fo-ATP合酶在ATP的生成中起着至关重要的作用，而解偶联的F1Fo-ATP合酶 构成线粒体通透性转换孔(MPTP)的分子基础，其开口 降低线粒体缓冲钙的能力。它的功能障碍与大脑老化和阿尔茨海默病有关；但 机制还不清楚；第二，在初步研究中，我们发现线粒体F1Fo 在过度表达的AD动物模型中，ATP合酶功能障碍是突出的突触线粒体缺陷 APP/Aβ(5xFAD小鼠)；第三，我们对AD脑和突触线粒体中该酶的进一步研究 5xFAD小鼠表现出OSCP亚基的选择性丢失以及OSCP与Aβ的相互作用。 此外，这种OSCP改变破坏了线粒体F1Fo ATP合成酶的完整性和功能。 最后，OSCP表达的恢复减轻了β诱导的神经元线粒体和突触 功能障碍。在拟议的研究中，我们将采用多种工具，包括我们新产生的神经元特异性 OSCP高表达5xFAD小鼠--抑制OSCP/Aβ相互作用的诱饵多肽及遗传性OSCP 下调并应用生物化学、细胞和分子生物学的多学科方法， 电生理学和活细胞成像。我们的目标是建立OSCP像差和OSCP之间的联系 突触线粒体F1Fo-ATP合酶在AD相关状态下的去调节及其对脑缺血的影响 突触线粒体功能障碍与突触损伤/认知障碍的发展 (特异性AIM2)对5xFAD小鼠。此外，我们还将探讨β介导的线粒体的机制 OSCP缺乏症(特异性AIM 3)。这一积极的发现将为线粒体和 阿尔茨海默病的突触缺陷和治疗阿尔茨海默病的新治疗策略的开发 在OSCP的保护下。此外，这些结果还可以推广到我们对线粒体的理解 有淀粉样β蛋白(Aβ)沉积的其他神经退行性疾病的功能障碍和突触衰竭， ATP缺乏和/或MPT激活。 OMB编号0925-0001/0002(08/12版批准至2015年8月31日)页面续格式页面

Program Director/Principal Investigator (Last, First, Middle): Du, Heng Project summary: Increasing evidence has suggested that mitochondrial dysfunction plays a central role in the pathogenesis of Alzheimer's disease (AD) . Compromised synaptic mitochondrial capabilities in ATP production and calcium retention have been proposed to be underlying the early synaptic injury in Aβ-rich milieus. However, the detailed molecular mechanisms of such Aβ-potentiated synaptic mitochondrial deficits still remain elusive. The specific hypothesis behind this proposed study is that mitochondrial F1Fo ATP synthase dysfunction via oligomycin sensitivity conferring protein (OSCP) aberrations is a potential cause of synaptic mitochondrial defects, leading to synaptic failure in AD-relevant conditions. This hypothesis is firmly built on the following observations: First, Mitochondrial F1Fo ATP synthase plays a vital role in ATP generation ; and uncoupled F1Fo ATP synthase constitutes the molecular basis of mitochondrial permeability transition pore (mPTP) , the opening of which lowers mitochondrial ability to buffer calcium .Its dysfunction has been implicated in aging brain and AD; but the mechanisms are not well understood; Second, in preliminary studies we have found that mitochondrial F1Fo ATP synthase dysfunction is a prominent synaptic mitochondrial defect in an AD animal model overexpressing APP/Aβ (5xFAD mice); Third, our further studies on this enzyme in AD brains and synaptic mitochondria from 5xFAD mice have shown the selective loss of its OSCP subunit and the interaction of OSCP with Aβ. Furthermore, such OSCP alterations disrupt the integrity and function of mitochondrial F1Fo ATP synthase. Lastly, the restoration of OSCP expression mitigates Aβ-induced neuronal mitochondrial and synaptic dysfunction. In the proposed studies, we will adopt multiple tools including our newly generated neuron-specific OSCP overexpressing 5xFAD mice, a decoy peptide to inhibit OSCP/Aβ interaction as well as genetic OSCP down-regulation and apply multidisciplinary approaches of biochemistry, cell and molecular biology, electrophysiology and live cell imaging. We aim to firmly establish the link between OSCP aberrations and synaptic mitochondrial F1Fo ATP synthase deregulation in AD-relevant condition and determine its impact on the development of synaptic mitochondrial dysfunction (Specific aim1) and synaptic injury/cognitive impairments (specific aim2) in 5xFAD mice. Furthermore, we will address the mechanisms of Aβ-mediated mitochondrial OSCP deficiency (specific aim3). The positive findings will provide a novel mechanism of mitochondrial and synaptic defects in AD and shed light on the development of novel therapeutic strategies for the treatment of AD by the protection of OSCP. In addition, the results can be extended to further our understanding of mitochondrial dysfunction and synaptic failure in other neurodegenerative diseases which have Amyloid beta (Aβ) deposition, ATP deficiency, and/or mPT activation. OMB No. 0925-0001/0002 (Rev. 08/12 Approved Through 8/31/2015) Page Continuation Format Page