The Effects of PP2A on TNF Signaling and Smoke-Induced Lung Injury

PP2A 对 TNF 信号传导和烟雾引起的肺损伤的影响

• 批准号: 8470691
• 负责人: Robert F Foronjy
• 金额: $ 42.16万
• 依托单位: ST. LUKE'S-ROOSEVELT INST FOR HLTH SCIS
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8470691
• 关键词: Accounting; Acetylcysteine; Acrolein; Address; Affect; Age; Aldehydes; Antioxidants; Binding; Biological Assay; Catalytic Domain; Cell Differentiation process; Cell Proliferation; Cells; Chronic Obstructive Airway Disease; Complement; Complex; DNA Binding; Deet; Development; Disease; Disulfides; Endothelial Cells; Enzymes; Epithelial Cells; Equilibrium; Eukaryotic Cell; Event; Exposure to; Gene Expression; Glutathione; Goals; Holoenzymes; Hour; Human; Hydrogen Peroxide; Immunoblotting; Immunoprecipitation; In Vitro; Inflammation; Inflammatory; JUN gene; Knock-out; Knockout Mice; Laboratories; Location; Lung; Lung diseases; MAP Kinase Gene; MAPK14 gene; MAPK8 gene; Measures; Mediating; Membrane; Messenger RNA; Modification; Mus; Nuclear; Nuclear Extract; Nutritional; Oxidation-Reduction; Peroxonitrite; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiological; Plasmids; Play; Post-Translational Protein Processing; Process; Protein Isoforms; Protein Kinase; Protein Serine/Threonine Phosphatase; Protein phosphatase; Proteins; Public Health; Publishing; Pulmonary Emphysema; Reaction; Reactive Oxygen Species; Receptor Signaling; Reduced Glutathione; Research; Role; S-ethyl glutathione; Sampling; Signal Pathway; Signal Transduction; Small Interfering RNA; Smoke; Stress; Structure of parenchyma of lung; Substrate Specificity; System; TNF gene; Testing; Thioredoxin; Tissue Sample; Transcription Factor AP-1; Transgenic Mice; Transgenic Organisms; Tumor Necrosis Factor Receptor; Tyrosine Phosphorylation; Xanthine Oxidase; Xanthines; base; buthionine; carbonyl group; cigarette smoke-induced; cigarette smoking; coping; crosslink; effective therapy; enzyme activity; glutathione peroxidase; improved; in vivo; inhibitor/antagonist; insight; lung injury; mortality; prevent; protein function; public health relevance; research study; response; superoxide dismutase 1; thioredoxin reductase; trend

DESCRIPTION (provided by applicant): To date, there are no effective therapies that can counteract the damaging effects of cigarette smoke exposure in the lung. In fact, the age-adjusted mortality for chronic obstructive pulmonary disease (COPD) has risen 71% over the past thirty years. To improve this trend more effective strategies of treating the underlying disease mechanisms need to be developed. We have recently published that superoxide dismutase-1 (SOD1), a lung antioxidant, prevents cigarette smoke-induced inflammation and emphysema formation in mice. Further studies in our laboratory demonstrate that the transgenic expression of human SOD1 and glutathione peroxidase-1 (GPX1) decreases JNK activation and AP-1 signaling within the lungs of mice. Importantly, these events correlate with the antioxidant-mediated increase in protein phosphatase 2A (PP2A) activity. This is significant since PP2A is the primary serine threonine protein phosphatase present in all eukaryotic cells. It dephosphorylates and inactivates both JNK and IKK; thus, PP2A is a major regulator of TNF signaling in the lung. PP2A is a heterotrimer enzyme composed of distinct isoforms of a structural subunit (A), a regulatory subunit (B) and a catalytic subunit (C). Post-translational modifications of the C subunit and dynamic exchange of variable B subunits regulate PP2A substrate specificity, activity, and intracellular distribution. PP2A activity is decreased by tyrosine phosphorylation of Tyr307 and disulfide cross-linking of the catalytic (C) subunit of the enzyme which are processes that are affected by reactive oxygen species(4, 5). SOD1 and GPX1 markedly increased protein phosphatase 2A (PP2A) activity in the lungs of these mice without altering PP2A expression or protein levels. Based on these findings, we hypothesize that redox balance can alter TNF signaling and smoke-induced lung injury by modifying PP2A activity in the lung. Reversible phosphorylation of proteins is the most important reaction for regulating protein function in eukaryotic cells. The intracellular phosphorylation of proteins enables the cell to respond to environmental and nutritional stresses by regulating gene expression, cellular proliferation and cell differentiation. The cell contains a tightly coordinated network of kinases and phosphatases that switch proteins from the phosphorylated to the dephosphorylated state in order to cope with various physiological challenges. While a significant body of research has elucidated the role that protein kinases exert in this process, much less is known about the effects of protein phosphatases. As noted above, PP2A is the major serine-threonine protein phosphatase in all eukaryotic cells. In fact, it accounts for as much as 1% of total cellular protein and for a large fraction of overall cellular phosphatase activity. However, its effects on inflammatory lung diseases such as COPD have not been well studied. This proposal will advance public health by specifically determining how PP2A regulates the TNF signaling pathway which plays a pivotal role in the development of smoke-induced lung injury. This project will achieve these goals by addressing three fundamental questions: 1) Does redox balance affect PP2A activity by modifying the holoenzyme complex? 2) Does modifying PP2A activity alter TNF signaling and affect the development of injurious responses to cigarette smoke exposure in the lung? 3) Does PP2A alter TNF signaling within the lungs of emphysema subjects? It is hoped that the insights gained from these studies will provide a more targeted approach of treating this disease. Importantly, our findings will have important implications for other diseases where TNF signaling and inflammation play a central role.

描述（由申请人提供）：迄今为止，还没有有效的疗法可以抵消香烟烟雾暴露对肺部的损害作用。事实上，过去 30 年来，慢性阻塞性肺疾病 (COPD) 的年龄调整死亡率上升了 71%。为了改善这一趋势，需要开发更有效的治疗潜在疾病机制的策略。我们最近发表了超氧化物歧化酶-1 (SOD1)（一种肺部抗氧化剂）可以预防小鼠香烟烟雾引起的炎症和肺气肿形成。我们实验室的进一步研究表明，人 SOD1 和谷胱甘肽过氧化物酶-1 (GPX1) 的转基因表达可降低小鼠肺内的 JNK 激活和 AP-1 信号传导。重要的是，这些事件与抗氧化剂介导的蛋白磷酸酶 2A (PP2A) 活性增加相关。这很重要，因为 PP2A 是所有真核细胞中存在的主要丝氨酸苏氨酸蛋白磷酸酶。它使 JNK 和 IKK 去磷酸化并失活；因此，PP2A 是肺部 TNF 信号传导的主要调节因子。 PP2A 是一种异源三聚体酶，由结构亚基 (A)、调节亚基 (B) 和催化亚基 (C) 的不同亚型组成。 C 亚基的翻译后修饰和可变 B 亚基的动态交换调节 PP2A 底物特异性、活性和细胞内分布。 Tyr307 的酪氨酸磷酸化和酶催化 (C) 亚基的二硫键交联会降低 PP2A 活性，这些过程受活性氧的影响 (4, 5)。 SOD1 和 GPX1 显着增加这些小鼠肺部的蛋白磷酸酶 2A (PP2A) 活性，而不改变 PP2A 表达或蛋白水平。基于这些发现，我们假设氧化还原平衡可以通过改变肺部的 PP2A 活性来改变 TNF 信号传导和烟雾引起的肺损伤。蛋白质的可逆磷酸化是真核细胞中调节蛋白质功能的最重要的反应。蛋白质的细胞内磷酸化使细胞能够通过调节基因表达、细胞增殖和细胞分化来应对环境和营养应激。该细胞包含紧密协调的激酶和磷酸酶网络，可将蛋白质从磷酸化状态转变为去磷酸化状态，以应对各种生理挑战。虽然大量研究已经阐明了蛋白激酶在此过程中发挥的作用，但人们对蛋白磷酸酶的作用知之甚少。如上所述，PP2A 是所有真核细胞中主要的丝氨酸-苏氨酸蛋白磷酸酶。事实上，它占细胞总蛋白的 1% 之多，并且占整个细胞磷酸酶活性的很大一部分。然而，其对慢性阻塞性肺病等炎症性肺部疾病的影响尚未得到充分研究。该提案将通过具体确定 PP2A 如何调节 TNF 信号通路来促进公众健康，TNF 信号通路在烟雾引起的肺损伤的发展中发挥着关键作用。该项目将通过解决三个基本问题来实现这些目标：1）氧化还原平衡是否通过修改全酶复合物影响 PP2A 活性？ 2) 改变 PP2A 活性是否会改变 TNF 信号传导并影响肺部对香烟烟雾暴露的有害反应的发展？ 3) PP2A 是否会改变肺气肿受试者肺内的 TNF 信号传导？希望从这些研究中获得的见解将为治疗这种疾病提供更有针对性的方法。重要的是，我们的发现将对 TNF 信号传导和炎症发挥核心作用的其他疾病产生重要影响。