Control of Anoxia-Reoxygenation Responses by the O2-sensing Enzyme EGL-9 Pathway

缺氧（缺氧）后再给氧会对多种疾病造成严重的有害影响。 医学状况，包括缺血性再灌注损伤和心肌梗死。动物如何感知 缺氧-复氧和防止组织损伤是根本的和未回答的问题。转录 缺氧诱导因子（HIF）是一种重要的细胞保护因子，可以对抗缺氧-复氧（A/R）诱导的细胞凋亡。 injui^. C. elegans基因egl-9，其编码HIF-1 α的02-敏感脯氨酰羟化酶。 1，已经导致鉴定了维持O2稳态的进化上保守的途径 在从线虫到人类的生物体中。EGL-9的哺乳动物HIF羟化酶同源物的抑制 对心肌缺血和再灌注损伤有明显的保护作用。使用自动行为跟踪 在改变O2浓度的条件下，我发现了一种叫做O2-ON的运动行为， O2-ON反应可以模拟哺乳动物组织反应的关键方面 缺血再灌注损伤。EGL-9对于O2-ON应答是必需的，并且介导缺氧的作用。 预调节对02- 0 N响应的抑制。通过一系列的基因筛查，我发现 CYSL-1作为EGL-9和细胞色素P450酶CYSL-13 A12的新调节剂， 类花生酸信号传导分子下游的EGL-9来控制02-ON反应。我还表演了 RNA-seq和分离的C. elegans突变体，定义了EGL的其他新的调节因子和靶点， 9/HIF-1通路。该项目的总体目标是鉴定和表征新的保守的 调节剂的生物反应A/R，这是由EGL-9途径调节，并确定 潜在的分子和细胞机制。在这个项目的K99阶段，我建立了 行为和细胞C. elegans模型的缺血-再灌注损伤，并表征了TNF-13 A12作为 PUFA-环氧合酶在控制O2-ON反应中的作用。在本项目的ROO阶段，我将进一步 确定A/R引起02-ON响应的关键机制，并确定新的调节剂， EGL-9通路的靶点，介导对A/R诱导的细胞损伤和行为的保护 答：A/R。在我的心血管研究所的新独立实验室里， 在加州大学旧金山分校的生理学在ROO阶段，优秀的科学环境将使我能够实现 研究目标，也促进我的智力互动和潜在的合作与生物学家和 临床医生寻求确定的基因和机制如何导致代谢和缺血性疾病的新疗法， 人类疾病K99/R 00提供的培训和支持将帮助我过渡到一个完全 独立和成功的PI。

Anoxia (lack of oxygen) followed by reoxygenation causes severe detrimental effects in a wide variety of medical conditions, including ischemic reperfusion injury and myocardial infarction. How animals sense anoxia-reoxygenation and prevent tissue injury are fundamental and unanswered issues. The transcription factor hypoxia inducible factor (HIF) is a key cell protector against anoxia-reoxygenation (A/R)-induced injui^. The discovery of the C. elegans gene egl-9, which encodes an 02-sensing prolyl hydroxylase of HIF- 1, has led to the identification of an evolutionarily conserved pathway central for maintaining 02 homeostasis in organisms from nematodes to humans. Inhibition of mammalian HIF hydroxylase homologs of EGL-9 strongly protects from myocardial ischemia and reperfusion injury. Using automated behavioral tracking under conditions of changing 02 concentrations, I discovered a locomotory behavior called the 02-ON response and have shown that the 02-ON response can model key aspects of mammalian tissue response to ischemia-reperfusion injury. EGL-9 is essential for the 02-ON response and mediates the effect of hypoxic preconditioning on the suppression of the 02-ON response. From a series of genetic screens, I discovered CYSL-1 as a new regulator of EGL-9 and a Cytochrome P450 enzyme CYP-13A12 that generates eicosanoid signaling molecules downstream of EGL-9 to control the 02-ON response. I also performed RNA-seq and isolated C. elegans mutants that define additional novel regulators and targets of the EGL- 9/HIF-1 pathway. The overall goal of this project is to identify and characterize the novel conserved regulators of biological responses to A/R, which is modulated by the EGL-9 pathway, and determine the underlying molecular and cellular mechanisms. In the K99 phase of this project, I have established behavioral and cellular C. elegans models for ischemia-reperfusion injury and characterized CYP-13A12 as a PUFA-epoxygenase in controlling the 02-ON response. In the ROO phase of this project, I will further determine the key mechanisms by which A/R causes the 02-ON response and identify novel regulators and targets of the EGL-9 pathway, which mediates protection from A/R-induced cellular injury and behavioral response to A/R. In my new independent lab in the Cardiovascular Research Institute and Department of Physiology at UCSF in the ROO phase, the outstanding scientific environment will enable me to achieve the research goals and also foster my intellectual interaction and potential collaboration with both biologists and clinicians to seek how identified genes and mechanisms lead to new therapeutics in metabolic and ischemic human disorders. The training and support provided by K99/R00 will facilitate my transition into a fully independent and successful PI.