Reductive Stress Induces Proteotoxic Cardiac Disease

还原性压力诱发蛋白毒性心脏病

• 批准号: 8886857
• 负责人: Rajasekaran Namakkal Soorappan
• 金额: $ 36.5万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-29 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8886857
• 关键词: Age-Months; Amyloid; Animal Model; Antioxidants; Apoptotic; Area; Biochemistry; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cardiovascular Diseases; Cells; Cessation of life; Chemicals; Chemistry; Chronic; Clinical; Cytoskeletal Proteins; Endoplasmic Reticulum; Environment; Enzymes; Equilibrium; Erythroid; Free Radicals; Functional disorder; Gene Targeting; Genes; Genetic; Glutathione; Goals; Health; Heart; Heart Diseases; Heart Hypertrophy; Heart failure; Heat shock proteins; Homeostasis; Human; Hypertrophy; Image; In Vitro; Knock-out; Knowledge; Laboratories; Lead; Mediating; Metabolic; Modeling; Molecular; Molecular Chaperones; Mus; Mutation; Myocardial; NADP; NQO1 gene; Nuclear; Outcome Study; Oxidation-Reduction; Oxidative Stress; Pathogenesis; Pathway interactions; Patients; Physicians; Physiology; Process; Proteins; Quality Control; Research; Response Elements; Scientist; Signal Transduction; Stress; System; Testing; Therapeutic; Therapeutic Intervention; Transcript; Transgenic Organisms; Ubiquitin; Ubiquitination; base; catalase; constriction; endoplasmic reticulum stress; experience; gene therapy; improved; in vivo; knock-down; mitochondrial dysfunction; mouse model; multicatalytic endopeptidase complex; next generation; prevent; protein aggregation; protein folding; protein function; research study; response; stress protein

DESCRIPTION (provided by applicant): The significance and pathogenic consequences of proteotoxicity and proteinopathy in failing hearts have received recent clinical notice. Accumulation of defective proteins and their aggregation impair proteostasis and lead to pathological consequences in cardiomyocytes. A homeostatic balance (proteostasis) between synthesis and degradation of defective proteins is crucial for the dynamically active cardiomyocytes. Mounting evidence indicates that a majority of protein aggregation cardiomyopathies (PAC) caused by mutations in cytoskeletal proteins or chaperones involve pre-amyloid aggregates, oxidative stress, mitochondrial dysfunction and apoptotic death of cardiomyocytes. We now demonstrate that constitutive activation of nuclear erythroid-2 like factor-2 (Nrf2) signaling is a potential mechanism for Reductive Stress (RS) and PAC in these pathogenic processes. Our findings pinpoint RS as the metabolic insult responsible for pathogenesis in human cardiac disease. Our long-term goal is to investigate the molecular mechanisms for RS mediated proteotoxic cardiac disease and explore relevant therapeutic interventions. We hypothesize that abnormal increases in intracellular reducing power contributes to RS, which will cause proteotoxic cardiac remodeling and dysfunction through impaired protein quality control mechanisms. Accordingly, we propose the following aims: (1) To determine whether chronic reductive stress (CRS) is sufficient to cause cardiac hypertrophy and pathological remodeling, (2) To determine whether CRS impairs endoplasmic reticulum (ER) and ubiquitin- proteasome function to promote proteotoxicity and protein aggregation and (3) To determine whether preventing RS or preserving ER function rescues the CaNrf2-TG mice from proteotoxic cardiac remodeling and dysfunction. To study these aims, we have established mouse models for RS by constitutively activating Nrf2 (CaNrf2) in the heart [CaNrf2-TG or Keap1-/-:aMHC-Cre-TG (cardiomyocyte-specific constitutive activation of Nrf2 signaling)]. First, we will determine the effects of RS on cardiac function, structural remodeling and stress- induced cardiac hypertrophy in mice with trans-aortic constriction. Next, we will study the effect of RS on redox potential of ER and investigate the mechanisms associated with ER stress and unfolded protein response pathways in the CaNrf2-TG or Keap1-/-:aMHC-CreTG mice with proteotoxic cardiac disease. Then, we will use pharmacological approaches to prevent RS or ER stress to rescue the proteotoxic cardiac disease. Alternatively, we will use genetic approaches to knock down Nrf2 to prevent RS and resultant proteotoxicity. A team of scientists and physicians with relevant experience in cardiac physiology, cardiac imaging, free-radical chemistry, biochemistry, molecular biology and gene therapy will be involved in this project. The proposal also includes a strong plan for educating the next generation (undergraduates and postgraduates) with cutting-edge research. The overall outcome of this study will yield new knowledge on RS and proteotoxic effects in the heart, which will likely enhance therapeutic applications in human patients in the next 5-6 years.

描述（由申请人提供）：最近临床注意到了衰竭心脏中蛋白毒性和蛋白病的意义和致病后果。缺陷蛋白的积累及其聚集损害了心肌细胞中的蛋白质稳态并导致病理后果。有缺陷的蛋白质的合成和降解之间的稳态平衡（蛋白质稳态）对于动态活跃的心肌细胞至关重要。越来越多的证据表明，大多数蛋白聚集性心肌病（PAC）引起的细胞骨架蛋白或分子伴侣的突变涉及前淀粉样蛋白聚集，氧化应激，线粒体功能障碍和心肌细胞的凋亡死亡。我们现在证明，核红细胞样因子-2（Nrf 2）信号的组成性激活是这些致病过程中还原应激（RS）和PAC的潜在机制。我们的研究结果指出RS是人类心脏病发病机制的代谢损伤。我们的长期目标是研究RS介导的蛋白毒性心脏病的分子机制，并探索相关的治疗干预措施。我们推测，细胞内还原力的异常增加有助于RS，这将通过受损的蛋白质质量控制机制引起蛋白毒性心脏重塑和功能障碍。因此，我们提出以下目标：（1）确定慢性还原性应激（CRS）是否足以引起心脏肥大和病理性重塑，（2）确定CRS是否损害内质网（ER）和泛素-蛋白酶体功能以促进蛋白质毒性和蛋白质聚集，以及（3）确定预防RS或保留ER功能是否挽救CaNrf 2-TG小鼠蛋白毒性心脏重塑和功能障碍。为了研究这些目的，我们通过组成性激活心脏中的Nrf 2（CaNrf 2）建立了RS小鼠模型[CaNrf 2-TG或Keap 1-/-：aMHC-Cre-TG（心肌细胞特异性组成性激活Nrf 2信号传导）]。首先，我们将确定RS对经主动脉缩窄小鼠的心脏功能、结构重塑和应激诱导的心脏肥大的影响。接下来，我们将研究RS对ER氧化还原电位的影响，并研究与ER应激和未折叠蛋白反应途径相关的机制，在CaNrf 2-TG或Keap 1-/-：aMHC-CreTG蛋白毒性心脏病小鼠中。然后，我们将使用药理学方法来防止RS或ER应激，以挽救蛋白毒性心脏病。或者，我们将使用遗传方法敲低Nrf 2，以防止RS和由此产生的蛋白毒性。一组在心脏生理学、心脏成像、自由基化学、生物化学、分子生物学和基因治疗方面具有相关经验的科学家和医生将参与这一项目。该提案还包括一个强有力的计划，以尖端研究教育下一代（本科生和研究生）。这项研究的总体结果将产生关于RS和心脏中蛋白毒性作用的新知识，这可能会在未来5-6年内增强人类患者的治疗应用。