Regulation of extracellular superoxide dismutase in human pulmonary arterial hype

细胞外超氧化物歧化酶在人肺动脉高压中的调节

• 批准号: 8210797
• 负责人: Eva S. Nozik
• 金额: $ 7.65万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-23 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8210797
• 关键词: Address; Adult; Affect; Animal Model; Antioxidants; Attenuated; Azacitidine; Biology; Blood Vessels; Bronchi; Cell Proliferation; Cells; Child; CpG Islands; Cytosine; DNA Methylation; Data; Development; Diagnosis; Disease; Disease Progression; Enzymes; Epigenetic Process; Event; Fibrosis; Foundations; Freezing; Gene Delivery; Gene Expression; Gene Proteins; Genes; Genetic Transcription; Genomics; Goals; Guanosine; Human; Human Development; Hypermethylation; Hypertension; Inflammation; Injury; Lead; Life; Lung; Lung Transplantation; Lung diseases; Measures; Mediating; Messenger RNA; Methylation; Modification; Molecular; National Heart, Lung, and Blood Institute; Normal Cell; Nucleotides; Organ Transplantation; Pathogenesis; Pathway interactions; Patients; Process; Promoter Regions; Protein Isoforms; Proteins; Pulmonary Circulation; Pulmonary Hypertension; Pulmonary artery structure; Reactive Oxygen Species; Regulation; Research; Research Personnel; Research Proposals; Role; Sampling; Serum; Smooth Muscle Myocytes; Superoxide Dismutase; Superoxides; Testing; Therapeutic; Time; Tissue Banking; Tissue Banks; Tissues; Transgenic Mice; Vascular Diseases; Vascular remodeling; Work; abstracting; attenuation; base; bisulfite; cancer cell; demethylation; disorder control; enzyme activity; extracellular; human disease; improved; inhibitor/antagonist; neoplastic cell; novel; novel therapeutics; promoter; protein expression; pulmonary arterial hypertension; tool

DESCRIPTION (provided by applicant): Idiopathic pulmonary arterial hypertension (IPAH) is a life-threatening disease of the pulmonary circulation affecting children and adults. Accumulating evidence indicates that one key factor that contributes to the pathogenesis of vascular diseases, including PAH, is an increase in reactive oxygen species, such as superoxide (O2-), that exceed antioxidant capabilities. One critically important antioxidant in the vessel wall is extracellular superoxide dismutase (EC-SOD), the sole enzymatic defense against extracellular O2-. EC-SOD is the most highly expressed SOD isoform in the vasculature under normal conditions, and EC-SOD expression is decreased in animal models of lung or vascular injury and several human diseases, including one study showing a decrease in EC-SOD protein in the bronchus of 8 patients with IPAH. Augmenting EC- SOD activity in transgenic mice or through adenoviral gene delivery attenuates pulmonary vascular remodeling and pulmonary hypertension. The regulation of EC-SOD in IPAH has not been investigated. It is now recognized that gene expression can be regulated by epigenetic modifications including cytosine methylation within the promoter region, specifically cytosines adjacent to guanosine nucleotides (CpG islands). New data identify CpG islands within the EC-SOD promoter that can be methylated, and indicate that hypermethylation of the EC-SOD promoter inhibits EC-SOD transcription in human cancer cells, contributing to enhanced tumor cell proliferation. Based on these data, we hypothesize that DNA methylation of the EC-SOD promoter mediates silencing of this protective gene and contributes to the pathogenesis of idiopathic pulmonary arterial hypertension. Aim 1 will utilize lung and pulmonary artery tissue and serum procured at the time of organ transplantation in patients with IPAH, disease-specific controls with PAH due to other causes, or patients without PAH to determine whether EC-SOD gene and protein as well as enzyme activity are decreased in IPAH and test the impact of EC-SOD expression on pulmonary artery smooth muscle cell proliferation. Specific Aim 2 will then use bisulfite genomic sequencing to test whether the EC-SOD promoter in pulmonary artery tissue and pulmonary artery smooth muscle cells from humans with IPAH is hypermethylated, and if reversal of methylation restores EC-SOD expression and normal cell proliferation. The tissue and cell samples used in this study will have been procured and processed through the efforts of the investigators of the Pulmonary Hypertension Breakthrough Initiative. Our findings will serve as strong preliminary data for the subsequent submission of a comprehensive RO1 application investigating the regulation of EC-SOD in IPAH. The long term goals are to establish new pathways important in the regulation of this pivotal antioxidant enzyme in the vessel wall, identify the role of extracellular superoxide in proliferation, inflammation and fibrosis contributing to pulmonary vascular remodeling, and provide a rationale for novel therapeutic tools to improve treatment of this lethal disease affecting children and adults. PUBLIC HEALTH RELEVANCE: This research proposal examines whether DNA methylation, increasingly recognized as a key epigenetic mechanism to regulate gene expression, regulates the transcription of a critically important antioxidant enzyme, extracellular superoxide dismutase, in the pulmonary artery of patients with idiopathic or familial pulmonary artery hypertension. This work will provide a strong foundation to understand the mechanisms responsible for loss of this essential antioxidant in human pulmonary arterial hypertension and provide a rationale for novel therapeutic strategies to improve treatment of this lethal disease affecting children and adults. (End of Abstract)

描述(申请人提供)：特发性肺动脉高压(IPAH)是一种危及生命的肺循环疾病，影响儿童和成人。越来越多的证据表明，包括PAH在内的血管疾病发病机制中的一个关键因素是超氧化物(O2-)等活性氧物种的增加，这些氧物种超过了抗氧化能力。血管壁中一种至关重要的抗氧化剂是细胞外超氧化物歧化酶(EC-SOD)，它是唯一一种防御细胞外O2-的酶。EC-SOD是正常情况下血管系统中表达最高的SOD亚型，在肺或血管损伤的动物模型和几种人类疾病中EC-SOD的表达降低，其中一项研究显示8例IPAH患者的支气管EC-SOD蛋白表达降低。在转基因小鼠中增强EC-SOD活性或通过腺病毒基因传递可以减轻肺血管重构和肺动脉高压。EC-SOD在IPAH中的调节作用尚未见报道。现在人们认识到，基因表达可以通过表观遗传修饰来调节，包括启动子区域内的胞嘧啶甲基化，特别是鸟苷核苷酸(CpG岛)附近的胞嘧啶。新的数据确定了EC-SOD启动子中可以甲基化的CpG岛，并表明EC-SOD启动子的超甲基化抑制了EC-SOD在人类癌细胞中的转录，有助于促进肿瘤细胞的增殖。基于这些数据，我们推测EC-SOD启动子的DNA甲基化介导了这一保护基因的沉默，并在特发性肺动脉高压的发病机制中发挥了作用。目的1利用肺高压患者、其他原因引起的肺高压患者和无肺高压患者在器官移植时获取的肺和肺动脉组织和血清，检测EC-SOD基因、蛋白和酶活性是否在IPAH中降低，并检测EC-SOD表达对肺动脉平滑肌细胞增殖的影响。然后，SPICAL AIM 2将使用亚硫酸氢盐基因组测序来测试患有IPAH的人的肺动脉组织和肺动脉平滑肌细胞中的EC-SOD启动子是否高甲基化，以及甲基化逆转是否恢复EC-SOD的表达和正常细胞增殖。这项研究中使用的组织和细胞样本将通过肺高压突破倡议的研究人员的努力获得和处理。我们的发现将为随后提交一份全面的RO1申请提供强有力的初步数据，该申请调查Ipah中EC-SOD的调节。长期目标是建立在调节血管壁这种关键抗氧化酶方面重要的新途径，确定细胞外超氧化物在促进肺血管重塑的增殖、炎症和纤维化中的作用，并为改进这种影响儿童和成人的致命疾病的治疗提供理论基础。 与公共健康相关：这项研究计划检查DNA甲基化是否调节特发性或家族性肺动脉高压患者的肺动脉中一种至关重要的抗氧化酶--细胞外超氧化物歧化酶的转录。DNA甲基化日益被认为是调节基因表达的关键表观遗传学机制。这项工作将为了解人类肺动脉高压中这种基本抗氧化剂丢失的机制提供坚实的基础，并为改进这种影响儿童和成人的致命疾病的治疗提供新的治疗策略的理论基础。(摘要结束)