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) 在哺乳动物细胞中由多种 NO 合酶产生，包括炎症期间高输出的诱导形式。 由于一氧化氮可能导致癌症发生和与年龄相关的神经变性，我们希望了解哺乳动物细胞如何抵抗一氧化氮的毒性。 我们已经鉴定出一组 12 种蛋白质，这些蛋白质是在正常人成纤维细胞中暴露于亚毒性水平的 NO 中诱导产生的，其中包括抗氧化酶血红素加氧酶 1 (HO-1)。 我们已经证明 HO-1 mRNA 的诱导是通过 NO 依赖性稳定性变化而发生的。 我们将探索这种调节机制，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）受转录控制，我们将测试特定转录调节因子在此表达中的作用。 我们已经在啮齿动物运动神经元中发现了对 NO 的适应性抵抗：暴露于低水平 NO 的细胞会诱导 HO-1，从而对更高水平（通常是细胞毒性）的 NO 产生抵抗。 我们将通过鉴定 NO 诱导基因并确定它们在防止 NO 介导的毒性中的作用来表征各种细胞类型中的这种反应。 HO-1 敲除小鼠将使我们能够确定 HO-1 在成纤维细胞、神经元和其他组织中的防御作用。 该项目同时致力于追踪一氧化氮损伤的生化标记（例如硝基酪氨酸），利用遗传学确定 HO-1 在诱导性 NO 抗性中的作用，阐明调控和信号转导途径，以及识别和克隆新的 NO 抗性防御基因。