GENETOXIC RESPONSE TO OXIDATIVE DAMAGE

对氧化损伤的遗传毒性反应

• 批准号: 3789874
• 负责人: N J HOLBROOK
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3789874
• 关键词: adult respiratory distress syndrome; age difference; cytotoxicity; fibroblasts; gene induction /repression; hyperoxia; injury /disease stressor; laboratory rat; oxidative stress; tissue /cell culture; transcription factor; xanthine oxidase

Oxidative stress, resulting from the exposure of cells to "reactive oxygen species" (ROS) is a major cause of both acute and chronic cell injury and is postulated to play an important role in aging. Major causes of oxidative stress in the cell include ionizing radiation, detoxification of foreign chemicals, inflammation, and normal metabolism. Intracellular targets of ROS include proteins, lipids and DNA. Although in bacteria many genes involving three distinct regulons have been shown to be induced by oxidative damage, little is known about the molecular response to oxidative stress in higher eukaryotes. Studies here have focused on characterization of the acute genetic response to oxidant damage in mammalian cells and tissues with hopes of identifying genes which play an important role in the cellular response to oxidative stress. Three different in vitro model systems of oxidative stress have been employed including 1) hyperoxia (95% oxygen) treatment of cultured lung fibroblasts, 2) xanthine-xanthine oxidase treatment of rat proximal tubular epithelial cells, and 3) the effects of the nephrotoxic cysteine conjugate, S-(1,2-dichlorovinyl)-L-cysteine (DCVD) on porcine renal epithelial cells. gadd153, a CCAAT/enhancer-binding (C/EBP)-related gene and putative transcriptional regulator, was shown to be induced by each of the treatments, suggesting that it represents a generalized response to oxidant injury. In additional studies with the in vitro cultured fibroblasts as well as in vivo studies examining lung tissue from rats exposed to 100% oxygen we have shown that two other C/EBP-related genes, C/EBPbeta and C/EBP, are also induced in response to hyperoxia. We have begun studies to compare the sensitivity of aged versus young rats to the damaging effects of hyperoxia. We have observed that old rats (24 months of age) are less susceptible to hyperoxia-induced lung injury than are young (6 months of age) rats. Mortality resulting from respiratory distress in young rats placed in 100% oxygen occurred at an average exposure of 66 hours compared to 88 hours exposure in old rats. We are currently examining whether this age-related difference in survival is correlated with any age-related difference in the genetic response to hyperoxia.

由于细胞暴露在“活性氧”下而产生的氧化应激 物种“(ROS)是急性和慢性细胞损伤的主要原因， 被认为在衰老过程中起着重要作用。主要原因是 细胞内的氧化应激包括电离辐射、解毒 外来化学物质、炎症和正常新陈代谢。细胞内 ROS的靶标包括蛋白质、脂质和DNA。尽管在细菌中 许多涉及三个不同的调节子的基因已经被证明是被诱导的 通过氧化损伤，对分子反应知之甚少 高等真核生物中的氧化应激。这里的研究主要集中在 氧化损伤的急性遗传反应的特征 哺乳动物细胞和组织，希望识别起作用的基因 在细胞对氧化应激的反应中发挥重要作用。 三种不同的体外氧化应激模型系统已经被 采用的方法包括：1)高氧(95%氧气)处理培养肺 成纤维细胞，2)黄嘌呤-黄嘌呤氧化酶对大鼠近端成纤维细胞的作用 肾小管上皮细胞；3)肾毒性半胱氨酸的作用 S-(1，2-二氯乙烯)-L-半胱氨酸结合物对猪肾脏的作用 上皮细胞。CCAAT/增强子结合(C/EBP)相关基因Gadd153 和可能的转录调节因子，被证明是由每一种 这些治疗，表明它代表了对 氧化损伤。在体外培养的其他研究中 成纤维细胞和体内研究检测大鼠肺组织 暴露在100%氧气中，我们已经证明了另外两个与C/EBP相关的基因， C/EBPβ和C/EBP也是对高氧的反应。 我们已经开始研究比较老年和年轻大鼠的敏感度。 高氧血症的破坏性影响。我们观察到老年老鼠(24只) 3个月龄)对高氧性肺损伤的易感性比 是年轻的(6个月大的)大鼠。呼吸系统引起的死亡率 放置在100%氧气中的幼鼠平均发生窘迫 老年大鼠暴露时间为66小时，而暴露时间为88小时。我们是 目前正在研究这种与年龄相关的存活率差异是否 与年龄相关的遗传反应中的任何差异相关 高氧症。