Genetics Analysis of Neuronal Hypoxic Stress Resistance

神经元耐缺氧应激的遗传学分析

• 批准号: 8629773
• 负责人: Christopher G Rongo
• 金额: $ 35.61万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-15 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8629773
• 关键词: Acute; Affect; Animals; Behavior; Behavioral; Binding; Biological; Brain; Brain Injuries; Caenorhabditis elegans; Calcium; Cells; Cellular biology; Cessation of life; Chimeric Proteins; Defect; Depressed mood; Endosomes; Face; Generations; Genes; Genus Mentha; Glutamate Receptor; Glutamates; Hippocampus (Brain); Homeostasis; Hydroxylation; Hypoxia; Hypoxia Inducible Factor; Injury; Interneurons; Ischemic Stroke; Life; Lobular Neoplasia; Locomotion; Mammals; Measurable; Mediating; Mediator of activation protein; Membrane; Membrane Protein Traffic; Mitochondria; Modeling; Molecular Genetics; Morbidity - disease rate; Movement; Mutation; Necrosis; Nematoda; Nerve Degeneration; Neurons; Orthologous Gene; Oxygen; Pathway interactions; Phosphorylation; Phosphorylation Site; Phosphotransferases; Physiological; Prevention; Procollagen-Proline Dioxygenase; Production; Proline; Protein Binding; Proteins; Proteomics; Reactive Oxygen Species; Receptor Activation; Recycling; Regulation; Resistance; Signal Transduction; Site; Stress; Stroke; Structure; Surface; Synapses; Synaptic Membranes; System; Tertiary Protein Structure; Testing; Thinking; Trauma; Traumatic Brain Injury; base; clinical application; disability; excitotoxicity; forward genetics; genetic analysis; hypoxia inducible factor 1; in vivo; killings; loss of function mutation; mitochondrial dysfunction; neurotransmitter release; new therapeutic target; novel; postsynaptic; prevent; receptor; research study; response; sensor; trafficking

DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) and ischemic stroke are leading causes of morbidity and disability, excitotoxically killing neurons via hypoxia. The underlying mechanism is thought to be a combination of glutamate receptor overactivation, deregulated calcium homeostasis, and mitochondrial dysfunction. Specifically, the hypoxia resulting from trauma or stroke results in membrane depolarization and hence the release of the neurotransmitter glutamate from affected neurons. High levels of acute glutamate overactivate receptors on neighboring neurons, thereby resulting in calcium influx and excitotoxicity. Mitochondrial dynamics become altered, influencing the production of ATP, as well as the release of calcium and Reactive Oxygen Species (ROS) from neuronal mitochondria. Agents that directly interfere with glutamate receptor activation have had limited clinical applicability because of their dramatic effect on receptor physiological function. Thus, it is important to identify new therapeutic targets in order to mitigate excitotoxicity after TBI or stroke. The discovery that regulated trafficking of glutamate receptors can modify synaptic efficacy has changed the thinking about mechanisms by which receptors contribute to excitotoxicity after neuronal trauma. Many species, including mammals, have mechanisms by which they protect themselves from glutamate-mediated excitotoxicity, although these mechanisms are poorly understood. Indeed, the movement of glutamate receptors into and out of synaptic membranes after post-trauma hypoxia in some cultured neuronal systems can modulate excitotoxicity. Do changes in glutamate receptor trafficking contribute to neuronal death in the intact animal, or are they part of a neuroprotective response to hypoxia? What factors regulate glutamate receptor trafficking in response to hypoxia? How else does hypoxia alter the cell biology of neurons? This proposal takes genetic, molecular, cell biological, and electrophysiological approaches in C. elegans to understand how hypoxia impacts neuron function. In Aim 1, it examines how hypoxia and components of the known hypoxia response pathway alter the membrane trafficking of receptors. In Aim 2, it characterizes how EGL-9, a prolyl hydroxylase that senses oxygen levels and responds to hypoxia, regulates LIN-10, a PTB/PDZ- domain protein (orthologous to the Mints) known to regulate glutamate receptor trafficking. In Aim 3, it examines how hypoxia and EGL-9 regulate mitochondrial dynamics through their regulation of DRP-1, a mediator of mitochondrial fission. In Aim 4, it examines the effects of this novel pathway on neuron survival in several neurodegenerative models. The proposed experiments advance the field in several ways. First, they identify a novel hypoxia response pathway. Second, they demonstrate how neurons use this novel pathway to protect themselves from hypoxia. Third, they show that regulated receptor trafficking and regulated mitochondrial dynamics are the underlying mechanism. Finally, they provide potential new therapeutic targets for minimizing brain damage following TBI and ischemic stroke.

描述(申请人提供)：创伤性脑损伤(TBI)和缺血性中风是致残率和致残率的主要原因，通过低氧兴奋毒性杀死神经元。其潜在的机制被认为是谷氨酸受体过度激活、钙稳态失调和线粒体功能障碍的组合。具体地说，创伤或中风引起的缺氧导致膜去极化，从而从受影响的神经元释放神经递质谷氨酸。高水平的急性谷氨酸过度激活邻近神经元上的受体，从而导致钙内流和兴奋性毒性。线粒体动力学发生改变，影响三磷酸腺苷的产生，以及神经元线粒体释放钙和活性氧(ROS)。直接干扰谷氨酸受体激活的药物因其对受体生理功能的显著影响而限制了其临床应用。因此，确定新的治疗靶点以减轻脑外伤或卒中后的兴奋性毒性是很重要的。谷氨酸受体的受控运输可以改变突触效能的发现，改变了人们对受体参与神经元创伤后兴奋性毒性机制的看法。许多物种，包括哺乳动物，都有保护自己免受谷氨酸介导的兴奋性毒性的机制，尽管这些机制鲜为人知。事实上，在一些培养的神经元系统中，谷氨酸受体在创伤后缺氧后进入和离开突触膜可以调节兴奋性毒性。谷氨酸受体转运的变化是导致完整动物神经元死亡的原因，还是 它们是对缺氧的神经保护反应的一部分吗？哪些因素调节谷氨酸受体在低氧时的转运？低氧还会如何改变神经元的细胞生物学？这一建议采用遗传学、分子、细胞生物学和电生理的方法来了解缺氧是如何影响神经元功能的。在目标1中，它研究了低氧和已知的低氧反应途径的组成部分如何改变受体的膜运输。在目标2中，它描述了EGL-9是如何调节LIN-10的，EGL-9是一种感知氧气水平并对低氧做出反应的Pro-羟基酶，LIN-10是一种PTB/PDZ结构域蛋白(与薄荷同源)，已知的是调节谷氨酸受体的运输。在目标3中，它研究了低氧和EGL-9如何通过调节线粒体分裂的媒介DRP-1来调节线粒体的动力学。在目标4中，它研究了这一新途径对几种神经退行性变模型中神经元存活的影响。拟议的实验在几个方面推动了这一领域的发展。首先，他们确定了一种新的低氧反应途径。其次，他们展示了神经元如何使用这种新的途径来保护自己免受缺氧的影响。第三，他们表明，受调控的受体运输和受调控的线粒体动力学是潜在的机制。最后，它们为减少脑外伤和缺血性中风后的脑损伤提供了潜在的新的治疗靶点。