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: 8676588
• 负责人: Robert F Foronjy
• 金额: $ 43.62万
• 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/8676588
• 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; 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(申请人提供)：到目前为止，还没有有效的治疗方法可以抵消暴露在肺部的香烟烟雾的有害影响。事实上，在过去的30年里，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，需要制定更有效的治疗潜在疾病机制的战略。我们最近发表了超氧化物歧化酶-1(SOD1)，一种肺部抗氧化剂，可以防止香烟烟雾引起的炎症和小鼠肺气肿的形成。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)的转基因表达降低了小鼠肺内JNK的激活和AP-1信号转导。重要的是，这些事件与抗氧化剂介导的蛋白磷酸酶2A(PP2A)活性的增加有关。这一点很重要，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去磷酸化和失活；因此，PP2A是肺中肿瘤坏死因子信号的主要调节因子。PP2A是一种由结构亚基(A)、调节亚基(B)和催化亚基(C)不同亚基组成的杂三聚体酶。C亚基的翻译后修饰和可变B亚基的动态交换调节PP2A底物的特异性、活性和细胞内分布。酪氨酸307的酪氨酸磷酸化和酶催化(C)亚单位的二硫键交联会降低PP2A的活性，这些过程都受到活性氧物种(4，5)的影响。SOD1和GPX1显著增加了这些小鼠肺中蛋白磷酸酶2A(PP2A)的活性，但不改变PP2A的表达或蛋白水平。基于这些发现，我们假设氧化还原平衡可以通过改变肺中PP2A的活性来改变肿瘤坏死因子信号和吸烟所致的肺损伤。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。细胞内蛋白质的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响应环境和营养压力。该细胞包含一个紧密协调的激酶和磷酸酶网络，将蛋白质从磷酸化状态切换到去磷酸化状态，以应对各种生理挑战。虽然大量的研究已经阐明了蛋白激酶在这一过程中发挥的作用，但对蛋白磷酸酶的影响知之甚少。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%，占细胞总磷酸酶活性的很大一部分。然而，它对COPD等炎症性肺部疾病的作用还没有得到很好的研究。这项建议将通过明确PP2A如何调节在烟雾诱导的肺损伤发展中起关键作用的肿瘤坏死因子信号通路来促进公众健康。这个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体影响PP2A活性？2)修改PP2A活性是否改变了肿瘤坏死因子信号并影响肺部对香烟烟雾暴露的损伤反应的发展？3)PP2A是否改变了肺气肿患者肺内的肿瘤坏死因子信号？希望从这些研究中获得的见解将为治疗这种疾病提供一种更有针对性的方法。重要的是，我们的发现将对肿瘤坏死因子信号和炎症发挥核心作用的其他疾病具有重要意义。