Cu,Zn-SOD, MMP-9, and Asbestosis

Cu、Zn-SOD、MMP-9 和石棉沉着病

• 批准号: 8243005
• 负责人: A BRENT CARTER
• 金额: --
• 依托单位: IOWA CITY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8243005
• 关键词: Alveolar Macrophages; Asbestos; Asbestosis; Attenuated; Biological; Cells; Cicatrix; Collagen; Copper; Data; Deposition; Development; Enzymes; Exposure to; Extracellular Matrix; Extracellular Signal Regulated Kinases; Family; Fiber; Fibroblasts; Fibrosis; Gelatinase B; Gene Expression; Generations; Genes; Genetic Transcription; Goals; Hydrogen Peroxide; Inflammatory; Inhibition of Matrix Metalloproteinases Pathway; Link; Liquid substance; Lung; Lung diseases; Matrix Metalloproteinases; Mediating; Metalloproteinase Gene; Mitochondria; Mitogen-Activated Protein Kinases; Molecular; Molecular Chaperones; Mus; Pathogenesis; Patients; Peroxides; Phenotype; Play; Production; Pulmonary Fibrosis; Reactive Oxygen Species; Regulation; Role; Signal Pathway; Signaling Molecule; Small Interfering RNA; Source; Time; Transcriptional Regulation; copper zinc superoxide dismutase; environmental agent; enzyme activity; extracellular; in vivo Model; macrophage; neglect; novel; promoter

DESCRIPTION (provided by applicant): Asbestosis is an important cause of pulmonary fibrosis. Aberrant extracellular matrix deposition is a hallmark of asbestos-induced pulmonary fibrosis and is characterized by an imbalance between matrix deposition and degradation. Asbestos fibers remain in the lung for extended periods of time, which leads to the release of reactive oxygen species (ROS), including H2O2, from alveolar macrophages. The release of H2O2 by alveolar macrophages plays an integral role in the pathogenesis of aberrant matrix deposition in asbestosis. Our preliminary data show that H2O2 is primarily generated in the mitochondria in macrophages and that the source of H2O2 is predominantly derived from the peroxide-generating enzyme, Cu,Zn-SOD, which is localized in the mitochondrial intermembrane space (IMS) after asbestos exposure. An emerging target for signaling molecules, such as H2O2, are the family of matrix metalloproteinases (MMPs) which regulate the fibrotic phenotype. In this regard, our preliminary data also demonstrate that alveolar macrophages obtained from patients with asbestosis have increased Cu,Zn-SOD activity, generate 10-fold more H2O2, and express 20-fold less MMP-9 compared to normal subjects. Moreover, this decrease in expression was associated with decreased MMP-9 activity in BAL fluid and increased collagen secretion by fibroblasts exposed to BAL fluid. There is limited data, however, on the molecular regulation of MMP gene transcription and MMP activity by peroxide-inducing enzymes, such as Cu,Zn-SOD, in pulmonary fibrosis. Our preliminary data also demonstrate that over expression of Cu,Zn-SOD significantly inhibits MMP-9 promoter activity and MMP-9 activity, and knockdown of Cu,Zn-SOD by siRNA enhances MMP-9 activity and reduces collagen secretion by fibroblasts. The signaling pathway linking H2O2 to MMP-9 gene expression involves MAP kinases. In addition to other MAP kinases, the ERK MAP kinase has been shown to regulate MMP-9 gene expression. Our data demonstrates that Cu,Zn-SOD-/- mice have high levels of activated ERK compared to WT mice. These novel preliminary data suggest that Cu,Zn-SOD and H2O2, via control of ERK, act as inhibitory inputs to the transcriptional regulation of the MMP-9 gene, which correlates with MMP-9 activity, and induces the development of pulmonary fibrosis. We postulate that mitochondrial Cu,Zn-SOD induces pulmonary fibrosis by modulating collagen deposition by a mechanism involving H2O2, ERK, and MMP-9. We will evaluate this hypothesis with three Specific Aims. Aim 1 will determine the mechanism by which Cu,Zn-SOD translocates and is activated in the IMS and increases the steady-state levels of H2O2. We will also determine the role of copper chaperone for Cu,Zn-SOD (CCS) in regulating translocation and activation. Aim 2 will determine the role of Cu,Zn-SOD in regulating MMP-9 gene expression and MMP-9 activity and the mechanism by which Cu,Zn-SOD inhibits ERK. Aim 3 will provide biological relevance utilizing an in vivo model of asbestosis to understand the interaction between alveolar macrophages and fibroblast collagen deposition. Although these studies are related to asbestosis, they will provide important clues in understanding inflammatory and fibrotic lung diseases and may provide potential targets to attenuate the development of pulmonary fibrosis. \

描述（由申请人提供）： 石棉沉着症是肺纤维化的重要原因。异常的细胞外基质沉积是石棉引起的肺纤维化的标志，其特征是基质沉积和降解之间的不平衡。石棉纤维在肺部停留较长时间，导致肺泡巨噬细胞释放活性氧 (ROS)，包括 H2O2。肺泡巨噬细胞释放的 H2O2 在石棉肺异常基质沉积的发病机制中起着不可或缺的作用。我们的初步数据表明，H2O2 主要在巨噬细胞的线粒体中产生，并且 H2O2 的来源主要来自过氧化物生成酶 Cu,Zn-SOD，该酶在石棉暴露后位于线粒体膜间隙 (IMS) 中。 H2O2 等信号分子的一个新兴靶标是调节纤维化表型的基质金属蛋白酶 (MMP) 家族。在这方面，我们的初步数据还表明，与正常受试者相比，从石棉沉滞症患者获得的肺泡巨噬细胞的 Cu,Zn-SOD 活性增加，产生的 H2O2 多 10 倍，MMP-9 的表达量少 20 倍。此外，这种表达的减少与 BAL 液中 MMP-9 活性的降低以及暴露于 BAL 液的成纤维细胞胶原蛋白分泌的增加有关。然而，关于肺纤维化中过氧化物诱导酶（例如 Cu,Zn-SOD）对 MMP 基因转录和 MMP 活性的分子调节的数据有限。我们的初步数据还表明，Cu,Zn-SOD 的过表达显着抑制 MMP-9 启动子活性和 MMP-9 活性，并且通过 siRNA 敲低 Cu,Zn-SOD 可增强 MMP-9 活性并减少成纤维细胞的胶原分泌。连接 H2O2 与 MMP-9 基因表达的信号通路涉及 MAP 激酶。除了其他 MAP 激酶外，ERK MAP 激酶已被证明可以调节 MMP-9 基因表达。我们的数据表明，与 WT 小鼠相比，Cu,Zn-SOD-/- 小鼠具有高水平的活化 ERK。这些新的初步数据表明，Cu、Zn-SOD 和 H2O2 通过控制 ERK，作为 MMP-9 基因转录调节的抑制性输入，与 MMP-9 活性相关，并诱导肺纤维化的发展。我们假设线粒体 Cu,Zn-SOD 通过涉及 H2O2、ERK 和 MMP-9 的机制调节胶原蛋白沉积，从而诱导肺纤维化。我们将通过三个具体目标来评估这一假设。目标 1 将确定 Cu,Zn-SOD 在 IMS 中易位和激活以及增加 H2O2 稳态水平的机制。我们还将确定 Cu,Zn-SOD (CCS) 的铜伴侣在调节易位和激活中的作用。目标2将确定Cu,Zn-SOD在调节MMP-9基因表达和MMP-9活性中的作用以及Cu,Zn-SOD抑制ERK的机制。目标 3 将利用体内石棉沉着模型提供生物学相关性，以了解肺泡巨噬细胞和成纤维细胞胶原沉积之间的相互作用。尽管这些研究与石棉沉着有关，但它们将为理解炎症和纤维化肺部疾病提供重要线索，并可能提供减轻肺纤维化发展的潜在靶点。 \