Investigating the role of system xc- in glutamate, glutathione and synapse homeostasis in vivo

研究系统 xc- 在体内谷氨酸、谷胱甘肽和突触稳态中的作用

• 批准号: 10116499
• 负责人: SANDRA J HEWETT
• 金额: $ 34.91万
• 依托单位: SYRACUSE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10116499
• 关键词: AMPA Receptors; Acetylcysteine; Acute; Address; Affect; Amino Acids; Antioxidants; Astrocytes; Biological Models; Brain; Brain Diseases; Chronic; Complement; Couples; Cysteine; Cystine; Data; Dendritic Spines; Disease; Dose; Electroencephalogram; Epilepsy; Equilibrium; Exhibits; Exons; Glutamate Receptor; Glutamates; Glutathione; Glutathione Disulfide; High Pressure Liquid Chromatography; Hippocampus (Brain); Homeostasis; Immunohistochemistry; Individual; Kainic Acid; Knockout Mice; Knowledge; Light; Maintenance; Measurement; Mediating; Molecular; Morphology; Mus; Mutation; Neuraxis; Neurons; Neurotransmitters; Oxidation-Reduction; Pentylenetetrazole; Pharmacology; Phenotype; Physiological; Process; Pump; Regulation; Role; Signal Transduction; Source; Specificity; Stroke; Sulfhydryl Compounds; Synapses; System; Testing; Time; Traumatic Brain Injury; Vertebral column; Western Blotting; antiporter; brain electrical activity; brain tissue; conditional knockout; design; electrical measurement; experimental study; extracellular; in vivo; interest; nervous system disorder; neuronal excitability; new therapeutic target; receptor; receptor expression; response; scale up; sensor technology; stem; therapeutic target; transmission process

PROJECT SUMMARY In several brain disorders including epilepsy, stroke and traumatic brain injury, an imbalance between the excitatory and inhibitory (E/I) neurotransmitter systems exists. Understanding fully the cellular and molecular processes that underlie normal, physiological transmission is the first step in determining how aberrations of such might be countered to provide such individuals with E/I imbalance symptomatic relief. Recent evidence from our lab demonstrates a role for the cystine/glutamate antiporter System xc- (Sxc-) ─ which exports glutamate and imports cystine, the latter of which is the rate-limiting substrate for the synthesis of the thiol antioxidant glutathione ─ in maintenance of E/I balance. Specifically, we find that sut/sut mice, which harbor a natural mutation in SLC7a11 (SLC7a11sut/sut) and are therefore devoid of Sxc-, are considerably more hyperexcitable than their wild-type littermates upon acute challenge with kainic acid or pentylenetetrazole. Paradoxically, after repeated sub-acute/sub-chronic administration of the same chemoconvulsants, SLC7a11sut/sut mice exhibit signs of hypoexcitability, a response polar opposite to that which occurs in wild-type littermate controls. The idea that these paradoxical findings may result from the same underlying mechanism ─ namely synaptic scaling ─ will be explored in this proposal. State-of-the-art in vivo sensor technology, as well as, cellular, molecular and pharmacological approaches will be used to test the hypothesis that chronic loss of Sxc- leads to a scaling up of glutamate receptors under basal conditions, whereas scaling down occurs under conditions of enhanced neuronal activity ─ both in efforts to stabilize neuronal firing. Whether these finding are mediated by changes in glutamate and/or glutathione will also be explored. Studies to determine the cellular specificity of response, with specific focus on the role of the astrocyte, are also planned. Overall, these studies are designed to increase our mechanistic understanding of the contribution of astrocyte Sxc- to glutamate, glutathione and activity homeostasis in in vivo brain. More broadly, these efforts complement other ongoing efforts to identify targets to treat the E/I imbalance that exists in many neurological disorders.

项目摘要 在几种脑部疾病中，包括癫痫，中风和创伤性脑损伤， 存在兴奋性和抑制性（E/I）神经递质系统。完全了解细胞和分子 基于正常，物理传播的过程是确定畸变的第一步 可能会反对这样的人，以使此类人有E/I不平衡的症状缓解。最近的证据 从我们的实验室中展示了胱氨酸/谷氨酸抗植物系统XC-（SXC-）的作用，该系统导出了谷氨酸 并进口胱氨酸，后者是硫醇抗氧化剂合成的速率限制底物 谷胱甘肽─维持E/I平衡。具体来说，我们发现有天然的SUT/SUT小鼠 SLC7A11（SLC7A11SUT/SUT）中的突变，因此没有SXC-，更为过度过度脱离 在用海藻酸或甲状腺乙酸甲酸甲酸酯急性挑战时，其野生型同窝窝倍植物。矛盾的是，之后 重复的亚急性/亚chronic给药相同的化学弹力，SLC7A11SUT/SUT小鼠暴露了迹象 在野生型窝窝对照中发生的反应性不足，与发生的反应相反。这个想法 这些自相矛盾的发现可能是由相同的基本机制造成的─即突触缩放级 - 将是 在此提案中探索。最先进的体内传感器技术以及细胞，分子和 药理学方法将用于检验以下假设，即慢性损失SXC会导致扩展 谷氨酸受体在基本条件下，而在增强的条件下进行缩小 神经元活性 - 均用于稳定神经元解击。这些发现是否是由变化介导的 还将探索谷氨酸和/或谷胱甘肽。研究以确定反应的细胞特异性，并 还计划了对星形胶质细胞的作用的特定关注。总体而言，这些研究旨在增加我们的 对星形胶质细胞SXC-对谷氨酸，谷胱甘肽和活动稳态的贡献的机械理解 体内大脑。从更广泛的角度来看，这些努力完成了其他持续的努力，以确定对待E/I的目标 在许多神经系统疾病中存在不平衡。