Age Related Change in Mitochondrial Angiotensin System and Mitochondrial Decline

线粒体血管紧张素系统的年龄相关变化和线粒体衰退

• 批准号: 9520509
• 负责人: Peter M. Abadir
• 金额: $ 16.35万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-15 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9520509
• 关键词: AGTR2 gene; Affect; Age; Aging; Anabolism; Angiotensin Receptor; Angiotensins; Animals; Apoptosis; Bioenergetics; Biogenesis; Cardiac; Cardiac Myocytes; Cell Line; Cell membrane; Cells; Confocal Microscopy; Coupled; Development; Disease; Elderly; Electron Microscopy; Energy Metabolism; Equilibrium; Event; Failure; Fluorescent Probes; Foundations; Functional disorder; Future; Generations; Human; Image; Impairment; In Situ; Intervention; Investigation; Knowledge; Link; Longevity; Losartan; Magnetic Resonance Spectroscopy; Maintenance; Measures; Mediating; Mitochondria; Mitochondrial DNA; Modeling; Mus; Myocardium; Nitric Oxide; Nitrogen; Organism; Outcome; Oxidative Stress; Oxygen; Pathway interactions; Peripheral; Placebos; Play; Process; Production; Proteins; Reactive Oxygen Species; Receptor, Angiotensin, Type 1; Reporter; Reporting; Role; Surface; System; TP53 gene; Testing; Tissues; To specify; Translating; Type 2 Angiotensin II Receptor; Western Blotting; age effect; age related; aged; base; design; improved; in vivo; inhibitor/antagonist; instrument; mitochondrial dysfunction; mouse model; public health relevance; receptor; receptor expression; repaired; theories; virtual

DESCRIPTION (provided by applicant): Aging and decline in mitochondrial function are closely linked. Key signs of mitochondrial dysfunction include increased generation of reactive oxygen species, fewer ATP molecules produced per O2 consumed, and increased apoptosis. The reduction in ATP translates to lower energy for cellular maintenance processes including mitobiogenesis and turnover. We recently reported the identification of a functional Mitochondrial Angiotensin System (MAS), and found that aging impacts the ratio of key angiotensin type 1 and type 2 receptors in mitochondria (AT1R and AT2R), that AT1R blocking agents may partially reverse these changes and improve mitochondrial function. Importantly, AT1R-/- mice have an enhanced life span by 25%, in part through an increase in mitochondrial numbers. The effects of aging on the expression of mitochondrial (mt) AT1R and mtAT2R and their contribution to age-related changes in mitochondrial dysfunction have not been previously studied. New preliminary evidence suggests that AT1R blockade in old mice may restore the age- related decline in mitochondrial energy production and improve mitophagy efficiency via alterations in p53- inducible protein (MIEAP) expression. We hypothesize that an age-related increase in mtAT1R/AT2R ratio mediates declines in mitochondrial energy metabolism via increased reactive oxygen species (ROS) production and impaired elimination of damaged mitochondria. In order to test this hypothesis we propose a comprehensive study of mtAT1R and mtAT2R, in control and losartan (AT1R blocker) treated, young and aged (38-month old) C57BL/6, AT1-/- and AT2-/- mice. Will use age related cardiac muscle bioenergetics failure as a model to study the impact of changes in mtAT1R and mtAT2R following proposed specific aims: 1. To identify age-related changes in peripheral angiotensin system (PAS) and MAS and their contribution to altered reactive nitrogen/oxygen species ROS/RNS generation, using Q-PCR, western blot, confocal and electron microscopy. Generation of ROS/RNS will be quantified in isolated cardiomyocytes and mitochondria from all our animal groups using specific fluorescent probes. 2. To specify the contribution of age-related changes in PAS and MAS to bioenergetic dysfunction by magnetic resonance spectroscopy and imaging in the cardiac tissue of living animals at baseline and after four weeks of placebo or losartan treatment. MAS contributions to the changes in bioenergetics will studied in isolated cardiac mitochondria from all animal groups. 3. To investigate the role of the PAS and MAS on mitochondrial biogenesis, repair, and elimination by utilizing a cardiac cell line (H9C2) instrumented with a P53 activity reporter to measure the effects of over-expressing AT1R and/or AT2R on MIEAP, oxidative stress, mtDNA damage and mitophagy. Similar outcomes will also be compared between control and LOS treated, young and aged (38-month old) C57BL/6, AT1-/- and AT2-/- mice.

描述（由申请人提供）：衰老和线粒体功能下降密切相关。线粒体功能障碍的关键症状包括活性氧生成增加、每消耗 O2 产生的 ATP 分子减少以及细胞凋亡增加。 ATP 的减少意味着细胞维持过程（包括有丝分裂和更新）的能量降低。我们最近报道了功能性线粒体血管紧张素系统（MAS）的鉴定，并发现衰老会影响线粒体中关键血管紧张素1型和2型受体（AT1R和AT2R）的比例，AT1R阻断剂可能部分逆转这些变化并改善线粒体功能。重要的是，AT1R-/- 小鼠的寿命延长了 25%，部分原因是线粒体数量增加。衰老对线粒体 (mt) AT1R 和 mtAT2R 表达的影响及其对线粒体功能障碍的年龄相关变化的贡献尚未被研究。新的初步证据表明，老年小鼠 AT1R 阻断可能会恢复与年龄相关的线粒体能量产生下降，并通过改变 p53 诱导蛋白 (MIEAP) 表达来提高线粒体自噬效率。我们假设，与年龄相关的 mtAT1R/AT2R 比率增加通过活性氧 (ROS) 产生增加和受损线粒体消除受损介导线粒体能量代谢下降。为了检验这一假设，我们建议对对照小鼠和氯沙坦（AT1R 阻滞剂）治疗的年轻和老年（38 个月大）C57BL/6、AT1-/- 和 AT2-/- 小鼠中的 mtAT1R 和 mtAT2R 进行全面研究。将使用年龄相关的心肌生物能学衰竭作为模型，研究 mtAT1R 和 mtAT2R 变化的影响，遵循拟议的具体目标： 1. 确定外周血管紧张素系统 (PAS) 和 MAS 的年龄相关变化及其对活性氮改变的贡献/氧物种ROS/RNS生成，使用Q-PCR、蛋白质印迹、共聚焦和电子显微镜。我们将使用特定的荧光探针对所有动物组的分离心肌细胞和线粒体中 ROS/RNS 的生成进行定量。 2. 通过基线时和安慰剂或氯沙坦治疗 4 周后活体动物心脏组织的磁共振波谱和成像，明确 PAS 和 MAS 的年龄相关变化对生物能功能障碍的影响。 MAS 对生物能学变化的贡献将在所有动物组的分离心脏线粒体中进行研究。 3. 为了研究 PAS 和 MAS 在线粒体生物发生、修复和消除中的作用，通过利用配备有 P53 活性报告基因的心肌细胞系 (H9C2) 来测量过度表达 AT1R 和/或 AT2R 对 MIEAP 的影响，氧化应激、线粒体DNA损伤和线粒体自噬。类似的结果也将在对照小鼠和 LOS 治疗小鼠、年轻小鼠和老年小鼠（38 个月大）的 C57BL/6、AT1-/- 和 AT2-/- 小鼠之间进行比较。