Genetic Analysis of Neuronal Hypoxic Stress Resistance

描述（由申请人提供）：创伤性脑损伤（TBI）和缺血性中风是发病和残疾的主要原因，通过缺氧和氧化应激、谷氨酸受体过度激活和钙稳态失调的组合，兴奋性毒性地杀死神经元。特别是，创伤或中风引起的缺氧会导致膜去极化，从而从受影响的神经元中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，从而导致钙流入和兴奋性毒性。直接干扰受体激活的药物因其对受体生理功能的显着影响而具有有限的临床应用性。因此，确定新的治疗靶点以减轻 TBI 或中风后的兴奋性毒性非常重要。调节谷氨酸受体的运输可以改变突触功效的发现改变了对受体在神经元创伤后导致兴奋性毒性机制的思考。特别是，在一些培养的神经元系统中，创伤后缺氧后，受体进出突触膜的运动可以调节兴奋性毒性。谷氨酸受体运输的变化是否会导致完整动物的神经元死亡，或者它们是对缺氧的神经保护反应的一部分？哪些因素调节谷氨酸受体运输以应对缺氧？该提案采用秀丽隐杆线虫的遗传方法来了解缺氧如何影响神经元细胞生物学。在目标 1 中，它研究了缺氧和已知的缺氧反应途径如何改变受体的膜运输。在目标 2 中，它描述了 EGL-9（一种感知氧气水平的 PHD 蛋白）如何调节 LIN-10（一种已知可调节谷氨酸受体运输的 PTB/PDZ 结构域蛋白）以应对缺氧。所提出的实验在几个方面推动了该领域的发展。首先，他们确定了一种新的缺氧反应途径。其次，他们展示了一种新的反应途径，神经元可以通过该途径保护自己免受缺氧的影响。第三，他们表明受调节的受体运输是潜在的机制。最后，它们为最大限度地减少 TBI 和缺血性中风后的脑损伤提供了潜在的新治疗靶点。 公共健康相关性：创伤性脑损伤和中风会造成大脑缺氧（低氧），引发神经递质谷氨酸的过度释放。高水平的谷氨酸反过来会通过过度激活神经元的谷氨酸受体而杀死神经元。了解谷氨酸受体如何响应缺氧而受到调节至关重要，以便开发治疗和预防创伤性损伤或中风后脑损伤的新应用。

DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) and ischemic stroke are leading causes of morbidity and disability, excitotoxically killing neurons via a combination of hypoxia and oxidative stress, glutamate receptor overactivation, and deregulated calcium homeostasis. In particular, the hypoxia resulting from trauma or stroke results in membrane depolarization and hence 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. Agents that directly interfere with 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. In particular, the movement of 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? This proposal takes a genetic approach in C. elegans to understand how hypoxia impacts neuron cell biology. In Aim 1, it examines how hypoxia and the known hypoxia response pathway alters the membrane trafficking of receptors. In Aim 2, it characterizes how EGL-9, a PHD protein that senses oxygen levels, regulates LIN-10, a PTB/PDZ-domain protein known to regulate glutamate receptor trafficking, in response to hypoxia. The proposed experiments advance the field in several ways. First, they identify a novel hypoxia response pathway. Second, they demonstrate a new response pathway by which neurons protect themselves from hypoxia. Third, they show that regulated receptor trafficking is the underlying mechanism. Finally, they provide potential new therapeutic targets for minimizing brain damage following TBI and ischemic stroke. PUBLIC HEALTH RELEVANCE: Traumatic brain injury and stroke create conditions of hypoxia (low oxygen) in the brain, triggering the excessive release of the neurotransmitter glutamate. High levels of glutamate in turn kill neurons by over- activating their glutamate receptors. It is critical to understand how glutamate receptors are regulated in response to hypoxia in order to develop novel applications for the treatment and prevention of brain damage resulting after traumatic injury or stroke.