Role and Regulation of SIRT3 in White Matter

SIRT3 在白质中的作用和调节

• 批准号: 8691154
• 负责人: Tatyana I. Gudz
• 金额: $ 32.7万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8691154
• 关键词: Accounting; Address; Apoptosis; Apoptotic; Biochemical; Bioenergetics; Brain; Brain Hypoxia-Ischemia; Brain Injuries; Brain Ischemia; Cause of Death; Cell Death Signaling Process; Cells; Ceramides; Cerebral Ischemia; Cessation of life; Chronic; Data; Deacetylation; Detection; Event; Failure; Feedback; Generations; Glutamates; Goals; In Vitro; Infarction; Intrinsic factor; Knockout Mice; Knowledge; Lasers; Lead; Life; Link; Lipids; Longevity; Mass Spectrum Analysis; Mediating; Metabolic Pathway; Metabolism; Methodology; Microscope; Mitochondria; Modeling; Molecular; Monitor; Myelin; Neuroglia; Neurons; Oligodendroglia; Outcome; Pathway interactions; Perinatal Hypoxia; Pharmaceutical Preparations; Play; Preventive; Protein Family; Regulation; Reperfusion Therapy; Reporting; Research; Role; Scanning; Scheme; Signal Pathway; Sirtuins; Sphingolipids; Stroke; Testing; Therapeutic; Toxic effect; Transgenic Mice; Traumatic Brain Injury; base; cell injury; design; dihydroceramide desaturase; disability; effective therapy; improved; in vivo; inhibitor/antagonist; mitochondrial dysfunction; multi-photon; nervous system disorder; novel; prevent; programs; public health relevance; response; sphingosine 1-phosphate; sphingosine kinase; white matter; white matter damage

DESCRIPTION (provided by applicant): White matter damage is an essential feature of stroke, traumatic brain injury and perinatal hypoxia/ischemia. Oligodendrocytes (OLs) are the myelin-forming glial cells of the brain, thus OL damage has profound consequences for the function of white matter. Our long-term goal is to reveal, in-depth, the mechanisms of OL damage for the design of novel and more effective therapeutic strategies. The focus of this project is on a novel mechanism of mitochondrial dysfunction leading to apoptotic OL death after brain ischemia/reperfusion (IR). A hallmark of OL metabolism is the generation of large quantities of sphingolipids which are key lipid components of myelin. In addition to their structural function, bioactive sphingolipids play fundamental roles in the regulation of proliferation and apoptosis. Ceramide, a pro-apoptotic sphingolipid, is tightly regulated in cells and its participation in cell death signaling pathways is controlled by a rapid conversion of ceramide into less deleterious sphingolipids, including sphingosine-1-phosphate, a pro-survival sphingolipid. Sirtuins, a family of protein deacetylases, are important regulators of metabolism and longevity. Sirtuin 3 (SIRT3) coordinates the adaptive responses of several metabolic pathways in mitochondria. Our preliminary data indicate that SIRT3 is involved in the reciprocal regulation of bioactive sphingolipid metabolites that ultimately results in OL apoptosis. Our goals are to define how SIRT3 participates in the apoptotic program of OLs after cerebral IR and to unravel how SIRT3 could be manipulated for preventive and therapeutic purposes. Our central hypothesis is that cerebral IR triggers SIRT3- mediated, ceramide-dependent OL apoptosis and that sphingosine-1-phosphate is a key regulator of SIRT3 activity in OLs. Our Specific Aims are: (1) Identify the mechanisms of SIRT3-mediated OL apoptosis; (2) Determine the mechanisms regulating SIRT3 activity in OLs. We will use a multi-disciplinary and integrative approach, combining in vitro and in vivo studies in transgenic and knockout mouse stroke models with modern pharmacological, biochemical and bioenergetics methodologies. To monitor mitochondrial function in live OLs, a laser scanning confocal/multi-photon microscope equipped with femtosecond laser and META spectral detection will be used. Accurate quantification of multiple natural sphingolipid species will be achieved by a state-of-the-art mass spectrometry-based methodology. At the conclusion of this research program, we should establish a mechanistic link between SIRT3, the key regulator of mitochondrial metabolic pathways, and mitochondrial dysfunction leading to OL apoptosis. These studies will reveal novel determinants of cell demise in stroke which are highly likely to serve as new targets for the rational design of more effective therapies. The proposed studies will generate a coherent and unified view of SIRT3's role in the mitochondrial pathobiology of OLs and this knowledge will benefit the research in stroke, traumatic brain injury, perinatal hypoxia/ischemia and chronic neurological disorders characterized by OL loss.

描述(申请人提供)：脑白质损伤是中风、创伤性脑损伤和围产期缺氧/缺血的基本特征。少突胶质细胞是脑内形成髓鞘的神经胶质细胞，因此少突胶质细胞的损伤对脑白质的功能有深远的影响。我们的长期目标是深入揭示OL损伤的机制，为设计新的、更有效的治疗策略提供依据。本项目的重点是研究脑缺血/再灌流后线粒体功能障碍导致OL凋亡死亡的新机制。OL代谢的一个标志是产生大量的鞘磷脂，这是髓鞘的关键脂肪成分。除了它们的结构功能外，生物活性鞘脂在调节细胞增殖和凋亡方面也发挥着重要的作用。神经酰胺是一种促凋亡的鞘脂，在细胞内受到严格的调控，其参与细胞死亡信号通路的过程是由神经酰胺迅速转化为危害较小的鞘脂来控制的，其中包括有利于生存的鞘磷脂-1-磷酸。Sirtuins是蛋白质脱乙酰酶家族，是新陈代谢和长寿的重要调节因子。Sirtuin3(SIRT3)在线粒体中协调多种代谢途径的适应性反应。我们的初步数据表明，SIRT3参与了生物活性鞘脂代谢产物的相互调节，最终导致OL凋亡。我们的目标 确定SIRT3如何参与脑缺血后OL的凋亡程序，并揭示SIRT3如何被操纵以达到预防和治疗的目的。我们的中心假设是大脑IR触发SIRT3介导的神经酰胺依赖的OL细胞凋亡，1-磷酸鞘氨醇是OLS中SIRT3活性的关键调节因子。我们的具体目标是：(1)确定SIRT3介导的OL凋亡的机制；(2)确定OLS中SIRT3活性的调节机制。我们将使用多学科的综合方法，将转基因和敲除小鼠中风模型的体外和体内研究与现代药理学、生化和生物能量学方法相结合。为了监测活体白斑的线粒体功能，将使用配备飞秒激光和偏光谱探测的激光扫描共聚焦/多光子显微镜。多种天然鞘脂物种的准确定量将通过最先进的基于质谱学的方法实现。在本研究项目结束时，我们应该在线粒体代谢途径的关键调节因子SIRT3与导致OL细胞凋亡的线粒体功能障碍之间建立机制联系。这些研究将揭示卒中细胞死亡的新决定因素，这些因素极有可能成为合理设计中风的新靶点 更有效的治疗方法。这些研究将对SIRT3‘S在OL线粒体病理生物学中的作用产生一个连贯和统一的观点，这一认识将有助于卒中、创伤性脑损伤、围产期缺氧/缺血和以OL丢失为特征的慢性神经疾病的研究。