ADAPTIVE RESISTANCE TO NITRIC OXIDE

对一氧化氮的适应性抵抗

• 批准号: 6173925
• 负责人: Bruce F. Demple
• 金额: $ 27.53万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-17 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6173925
• 关键词: biological signal transduction; cell type; cytotoxicity; enzyme mechanism; fibroblasts; gene targeting; genetic regulation; genetic transcription; genetically modified animals; heme oxygenase; laboratory mouse; messenger RNA; mitogen activated protein kinase; neoplasm /cancer genetics; nitric oxide

Nitric oxide (NO) is produced in mammalian cells by several NO synthases, including an inducible form with high output during inflammation. Since NO may contribute to carcinogenesis and age- related neurodegeneration, we wish to understand how mammalian cells counteract NO toxicity. We have identified a group of 12 proteins induced in normal human fibroblasts by exposure to subtoxic levels of NO, including the antioxidant enzyme heme oxygenase 1 (HO-1). We have shown that the induction of HO-1 mRNA occurs via NO-dependent changes in its stability. We will explore the mechanism of this regulation and try to define the signal transduction pathway for post-transcriptional control of HO-1. Other genes (e.g., MAP kinase phosphatase MKP-1/CL100) are controlled transcriptionally, and we will test specific transcription regulators for their roles in this expression. We have identified an adaptive resistance to NO in the rodent motor neurons: cells exposed to low-level NO that induces HO-1 become resistant to much higher (usually cytotoxic) levels of NO. We will characterize this response in various cell types by identifying NO-inducible genes and determining their roles in protection against NO-mediated toxicity. HO-1 knockout mice will allow us to define the defensive role of HO-1 in fibroblasts, neurons, and other tissues. This project involves parallel efforts to follow biochemical markers of nitric oxide damage (e.g., nitrotyrosine), to use genetics to establish the role of HO-1 in inducible resistance to NO, to elucidate regulatory and signal transduction pathways, and to identify and clone novel defense genes for NO resistance.

一氧化氮（NO）在哺乳动物细胞中通过几种无合酶产生，包括在炎症过程中具有高输出的诱导形式。 由于NO可能有助于癌变和与年龄相关的神经变性，因此我们希望了解哺乳动物细胞如何抵消NO毒性。 我们已经通过暴露于NO的无氧水平，包括抗氧化剂酶血红素氧酶1（HO-1），确定了在正常人成纤维细胞中诱导的12种蛋白质。 我们已经表明，HO-1 mRNA的诱导是通过其稳定性无依赖性变化而发生的。 我们将探讨该调节的机制，并尝试定义HO-1转录后控制的信号转导途径。 其他基因（例如，MAP激酶磷酸酶MKP-1/CL100）受到转录的控制，我们将测试特定的转录调节剂在该表达中的作用。 我们已经确定了啮齿动物运动神经元中对NO的自适应性：暴露于低水平NO的细胞会诱导HO-1对NO的更高（通常是细胞毒性）水平的抗性。 我们将通过鉴定不可诱导的基因并确定其在防止无介导的毒性中的保护中来表征各种细胞类型的反应。 HO-1敲除小鼠将使我们能够定义HO-1在成纤维细胞，神经元和其他组织中的防御作用。 该项目涉及遵循一氧化氮损伤的生化标志物（例如硝基酪氨酸）的生化标志物，以使用遗传学来确定HO-1在诱导性耐药性中的作用，以阐明调控性和信号传递途径，并识别和识别和克隆新颖的防御基因，以确定耐药性。