The role of endonuclease G in nuclear apoptosis of atrophying skeletal muscle

核酸内切酶G在萎缩骨骼肌核凋亡中的作用

• 批准号: 8049608
• 负责人: Esther E Dupont-Versteegden
• 金额: $ 15.96万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8049608
• 关键词: Ablation; Acquired Immunodeficiency Syndrome; Age; Animals; Apoptosis; Apoptotic; Atrophic; Attenuated; Biological Assay; Biological Models; Caspase; Cell Membrane Permeability; Cell Nucleus; Cessation of life; Chelating Agents; Chronic Disease; Congestive Heart Failure; DNA Fragmentation; Data; Deferoxamine; Development; Disease; Disuse Atrophy; Elderly; Enzymes; Event; Exhibits; Exploratory/Developmental Grant for Diagnostic Cancer Imaging; GTP-Binding Proteins; Gastrocnemius Muscle; Goals; In Vitro; Intervention; Iron; Knockout Mice; Knowledge; Lasers; Lead; Limb structure; Location; Malignant Neoplasms; Measures; Mechanics; Mediating; Mitochondria; Mitochondrial Proteins; Modeling; Molecular; Mus; Muscle; Muscle Fibers; Muscle Proteins; Muscular Atrophy; NIH Program Announcements; Nuclear; Nuclear Envelope; Oxidative Stress; Pathway interactions; Permeability; Process; Protein Biosynthesis; Public Health; Regulation; Research; Research Project Grants; Research Proposals; Role; Skeletal Muscle; Soleus Muscle; Stimulus; Structure; Study models; Suspension substance; Suspensions; System; Testing; Therapeutic; Therapeutic Intervention; Time; Tissues; United States National Institutes of Health; Wild Type Mouse; Withdrawal; Work; age related; base; combat; endonuclease; endonuclease G; in vitro Model; innovation; insight; interstitial cell; muscle form; novel; novel therapeutic intervention; outcome forecast; oxidative damage; prevent; protein degradation; public health relevance; research study; response; sarcopenia

DESCRIPTION (provided by applicant): Skeletal muscle atrophy is an important determinant in the loss of independence in elderly and is associated with poor prognosis in chronic disease states. Identifying mechanisms of atrophy will enable us to develop therapeutic strategies to prevent or treat the loss of muscle mass. We have shown previously that myofiber nuclear apoptosis occurs in muscles undergoing disuse-induced or age-associated muscle atrophy and that the caspase-independent mitochondrial enzyme endonuclease G (EndoG) is translocated to nuclei during atrophy, possibly inducing DNA fragmentation in a subset of nuclei. Therefore, we hypothesize that nuclear apoptosis which occurs in atrophying skeletal muscle is mediated by EndoG. In Specific Aim 1 we will determine whether EndoG is required for the apoptotic response in skeletal muscle during disuse atrophy using EndoG knockout (KO) mice. Mice will be hind limb suspended (HS) and nuclear loss, apoptosis and atrophy will be assayed. In addition, we hypothesize that increased permeability of the nuclear membrane due to elevated oxidative stress with atrophy is necessary for EndoG to enter the nucleus. Wild type (WT) mice will be treated with an iron-chelator and translocation of EndoG, oxidative damage, nuclear endonuclease activity and nuclear apoptosis will be measured. In Specific Aim 2 we will study the consequences of nuclear changes on skeletal muscle atrophy. First, permeability changes of nuclei of WT mice after (HS) will be studied in vitro and correlated to oxidative stress to determine whether this is directly responsible for the entry of molecules into the nucleus. Additionally, we will test directly whether the loss of nuclei induces atrophy by eliminating muscle nuclei by laser ablation and assaying for muscle atrophy and protein loss. Lastly, we propose to develop an in vitro model of disuse atrophy by mechanical stimulus withdrawal and compare this to an in vitro atrophy model of oxidative stress. The role of EndoG in nuclear apoptosis in these models will be tested. In summary, the proposed experiments will enable us to determine the role of EndoG-mediated nuclear apoptosis in skeletal muscle atrophy. These results may be not only be used to develop strategies to combat muscle atrophy, but may also yield novel insight into mechanisms of apoptosis in other tissues. Relevance to public health: Muscle atrophy is associated diseases such as cancer, AIDS, and congestive heart failure, and has been suggested as a main contributor to the loss of independence in elderly. We showed that apoptosis is an important event in the process of muscle atrophy. Identifying underlying mechanisms may lead to therapeutic interventions, not just in decreasing atrophy, but in preventing it. Additionally, identifying pathways and molecules underlying the process of nuclear apoptosis in muscle will increase our knowledge about apoptosis in other tissues as well, likely leading to interventions and treatments in fields such as cancer. PUBLIC HEALTH RELEVANCE: Skeletal muscle atrophy is associated diseases such as cancer, AIDS, and congestive heart failure, and has been suggested as a main contributor to the loss of independence in elderly. We have shown that nuclear apoptosis is an important event in the process of muscle atrophy. Identifying underlying mechanisms may lead to new therapeutic interventions, not just in decreasing atrophy, but particularly in preventing it. Additionally, identifying pathways and molecules underlying the process of nuclear apoptosis in muscle will increase our knowledge about apoptosis in other tissues as well, possibly leading to new interventions and treatments in fields such as cancer.

描述（由申请人提供）：骨骼肌萎缩是老年人失去独立性的重要决定因素，并且与慢性疾病状态的预后不良有关。识别萎缩的机制将使我们能够制定治疗策略，以防止或治疗肌肉质量的损失。我们先前已经表明，肌纤维核凋亡发生在经历了残留诱导的或与年龄相关的肌肉萎缩的肌肉中，并且与caspase无关的线粒体酶内核酸内核酸内核酸内核酸内核酸内核酸酶G（内原）被转移到萎缩过程中的核，可能诱导Neuclei subset of Neuclei的DNA片段。因此，我们假设在萎缩骨骼肌中发生的核细胞凋亡是由内托介导的。在特定的目标1中，我们将确定使用内og敲除（KO）小鼠在废弃萎缩期间骨骼肌中凋亡反应是否需要内传。将分析小鼠的后肢悬浮（HS），核损失，凋亡和萎缩将被测定。此外，我们假设由于氧化应激与萎缩升高引起的核膜的渗透性增加是进入核的必要条件。将测量野生型（WT）小鼠的野生型小鼠，并将测量氧化损伤，氧化损伤，核核酸内切酶活性和核凋亡的易位治疗。在特定目标2中，我们将研究核变化对骨骼肌萎缩的后果。首先，将在体外研究（HS）后WT小鼠核的渗透性变化，并与氧化应激相关，以确定这是否直接负责分子进入细胞核。此外，我们将直接测试核的丧失是否通过激光消融和分析肌肉萎缩和蛋白质丧失来消除肌肉核是否诱导萎缩。最后，我们建议通过机械刺激戒断开发一种体外的废除萎缩模型，并将其与氧化应激的体外萎缩模型进行比较。在这些模型中，内og在核凋亡中的作用将进行测试。总而言之，提出的实验将使我们能够确定内生介导的核凋亡在骨骼肌萎缩中的作用。这些结果不仅可以用于制定抗击肌肉萎缩的策略，而且还可能对其他组织中凋亡的机制产生新的见解。与公共卫生有关：肌肉萎缩是相关的疾病，例如癌症，艾滋病和充血性心力衰竭，并被认为是老年人失去独立性的主要贡献者。我们表明凋亡是肌肉萎缩过程中的重要事件。识别潜在的机制可能会导致治疗性干预措施，而不仅仅是减少萎缩，而且可以预防萎缩。另外，识别肌肉核凋亡过程的途径和分子将增加我们对其他组织中凋亡的了解，这可能会导致癌症等领域的干预和治疗。 公共卫生相关性：骨骼肌萎缩是相关的疾病，例如癌症，艾滋病和充血性心力衰竭，并被建议作为老年人失去独立性的主要贡献者。我们已经表明，核凋亡是肌肉萎缩过程中的重要事件。识别潜在的机制可能会导致新的治疗干预措施，而不仅仅是减少萎缩，尤其是在预防萎缩方面。此外，识别肌肉核凋亡过程的途径和分子将增加我们对其他组织中凋亡的了解，这可能会导致癌症等领域的新干预和治疗。