SKN-1 Regulation and Oxidative Stress Resistance in C. elegans

描述（由申请人提供）：氧化应激引起的细胞损伤是多种疾病病理的核心。哺乳动物细胞通过保守的转录反应来抵抗氧化应激，其中Nrf蛋白诱导II期解毒酶基因的表达。关于这种氧化应激防御是如何被控制的，以及如何在治疗上加以利用，还有很多有待研究。在线虫秀丽隐杆线虫中，我们已经证明这种氧化应激反应是由与Nrf蛋白相关的SKN-1转录因子调控的。在胚胎中，母体提供的SKN-1启动了喂养/消化系统的发育。我们发现，在胚胎后期，SKN-1在肠和ASI化学感觉神经元中表达，并且是抵抗氧化应激和正常寿命所必需的。我们还获得了令人兴奋的新发现，即在肠道中SKN-1的定位受到p38、GSK-3和胰岛素样信号的调节，显然是通过SKN-1的直接磷酸化。我们的研究结果表明，SKN-1整合了多种应激和代谢输入，并为研究这种应激反应提供了有价值的全生物模型。在新的项目中，我们将研究这些信号如何调节SKN-1及其功能，并利用秀丽隐杆线虫的优势来确定控制这种应激反应的其他机制。在Aim 1中，我们将确定SKN-1在不同组织中的表达如何促进其功能，我们将测试SKN-1在肠道中如何调节的模型，包括一种SKN-1形式对线粒体应激作出反应的令人兴奋的假设。在Aim 2中，我们将研究胰岛素样信号如何调节SKN-1，以及SKN-1如何影响胰岛素样信号的生物学效应。在Aim 3中，我们将使用微阵列来鉴定额外的SKN-1靶基因和功能，并使用RNA干扰筛选来鉴定调节SKN-1的新机制。这项工作将极大地扩展我们对这种氧化应激反应是如何调节的，以及协调这种反应的蛋白质的生物学功能的理解。摘要：氧化应激（细胞自由基水平过高）在许多疾病中都很重要，包括糖尿病、动脉粥样硬化和癌症。一种对抗氧化应激的新方法是利用先天的细胞机制来防御它。在这个项目中，我们将使用一个简单的线虫模型来识别和研究控制这种应激防御的机制，并研究这种应激防御如何促进包括胰岛素反应在内的重要生物过程。

DESCRIPTION (provided by applicant): Cellular damage caused by oxidative stress is central to the pathology of a wide variety of diseases. Mammalian cells defend against oxidative stress through a conserved transcriptional response in which the Nrf proteins induce expression of Phase II detoxification enzyme genes. Much remains to be learned about how this oxidative stress defense is controlled, and might be harnessed therapeutically. In the nematode C. elegans, we have shown that this oxidative stress response is orchestrated by the SKN-1 transcription factor, which is related to Nrf proteins. In the embryo, maternally provided SKN-1 initiates development of the feeding/digestive system. We have found that during postembryonic stages SKN-1 is expressed in the intestine and ASI chemosensory neurons, and is required for resistance to oxidative stress and for normal longevity. We have also obtained the novel and exciting observation that in the intestine SKN-1 localization is regulated by p38, GSK-3, and insulin-like signaling, apparently through direct SKN-1 phosphorylation. Our findings indicate that SKN-1 integrates multiple stress and metabolic inputs, and provide a valuable whole-organism model for studying this stress response. In the new project, we will investigate how these signals regulate SKN-1 and its functions, and employ advantages of C. elegans to identify additional mechanisms that control this stress response. In Aim 1, we will determine how expression of SKN-1 in different tissues contributes to its functions, and we will test models for how SKN-1 is regulated in the intestine, including the exciting hypothesis that one SKN-1 form responds to mitochondrial stress. In Aim 2 we will study how insulin-like signaling regulates SKN-1, and how SKN-1 influences biological effects of insulin-like signaling. In Aim 3, we will use microarrays to identify additional SKN-1 target genes and functions, and RNA interference screening to identify novel mechanisms that regulate SKN-1. This work will greatly expand our understanding of how this oxidative stress response is regulated, and of the biological functions of the protein that orchestrates this response. Lay Summary: Oxidative stress (excessive levels of cellular free radicals) is important in many diseases, including diabetes, atherosclerosis, and cancer. A new means of combating oxidative stress would be to harness innate cellular mechanisms that can defend against it. In this project, we will use a simple nematode model to identify and study mechanisms that control this stress defense, and to investigate how this stress defense contributes to important biological processes that include responses to insulin.