Metabolic control of neuronal activity by fuel substrate switching

通过燃料底物转换对神经元活动的代谢控制

• 批准号: 8697160
• 负责人: Nika N Danial
• 金额: $ 35.12万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-15 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8697160
• 关键词: Acetyl Coenzyme A; Address; Affect; Amino Acids; Animals; Anticonvulsants; Apoptosis; Astrocytes; BCL2 gene; Behavior; Behavioral; Biosensor; Brain; Carbon; Cessation of life; Chemicals; Citrates; Citric Acid Cycle; Consumption; Cultured Cells; Cytoplasmic Granules; Employee Strikes; Epilepsy; Exhibits; Fatty Acids; Fingerprint; Generations; Genetic; Glucose; Glutamates; Glutathione; Glycolysis; Goals; Image; Individual; Intractable Epilepsy; Ketone Bodies; Lead; Learning; Life; Link; Measurement; Metabolic; Metabolic Control; Metabolic Pathway; Metabolism; Mitochondria; Modification; Molecular; Monitor; Mus; Mutant Strains Mice; Mutation; NADH; Neurons; Neurophysiology - biologic function; Neurotransmitters; Output; Oxidation-Reduction; Pathway interactions; Pentosephosphate Pathway; Pharmaceutical Preparations; Population; Potassium; Probability; Protein Family; Proteins; Pyruvate; Reducing diet; Research; Resistance; Seizures; Signal Transduction; Slice; Synapses; Testing; Translating; Work; cofactor; effective therapy; gamma-Aminobutyric Acid; genetic manipulation; glucose metabolism; glucose uptake; improved; ketogenesis; ketogenic diet; metabolomics; mutant; neuronal excitability; oxidation; public health relevance

DESCRIPTION (provided by applicant): Metabolic control of neuronal activity by fuel substrate switching. Fuel metabolism is important not only for cellular life-and-death decisions of neurons and astrocytes in the brain, but also as a key regulator of neuronal activity. A remarkable example of how metabolism can alter brain activity is the strong resistance to epileptic seizures exhibited by mice with deletion or alteration of BAD, a BCL-2 family protein that imparts reciprocal effects on glucose and ketone body consumption independent of its ability to regulate apoptosis. We have found that alterations in BAD's metabolic function can lead to reduced mitochondrial oxidation of glucose and enhanced oxidation of ketone bodies, in both neurons and astrocytes. Similar to animals treated with ketogenic diet, BAD mutant mice with these metabolic changes show a striking resistance to behavioral and electrographic seizures induced by chemical proconvulsants. Genetic and electrophysiologic studies also show that these same mutations in BAD increase the open probability of the ATP-sensitive potassium (KATP) channels and that activation of these channels is a necessary intermediate in this metabolically induced seizure resistance. Our proposed studies address two key questions about the mechanism by which BAD alters metabolism and neuronal excitability. The first question is at the level of the metabolic pathways for fuel utilization: What are the precise steps at which the metabolism of glucose and ketone bodies is changed when BAD is modified? Targeted metabolomics and 13C tracing will be used in conjunction with genetic manipulation of BAD to learn specifically how glucose and ketone bodies are routed through different metabolic pathways, and how this routing is affected by BAD, in cultured neurons and astrocytes as well as in brain slices. Second, what are the possible causes and consequences of KATP channel activation in BAD mutant neurons? We will employ fluorescent biosensors to assess the levels of key metabolic signals - ATP, ROS/glutathione redox, and NADH redox - in individual neurons and astrocytes in culture or slices, to learn the causes of KATP channel activation. Complementary electrophysiological studies will address how excitability and signaling in dentate granule neurons are altered in BAD mutant brain slices. The answer to these questions should give an integrated picture of the pathway connecting BAD and fuel metabolism with altered neuronal excitability. Understanding this pathway should yield valuable clues for translating this potent anticonvulsant effect of metabolism into improved therapies for the many individuals with intractable epilepsy.

描述（由申请人提供）：通过燃料基板切换对神经元活动的代谢控制。燃料代谢不仅对于大脑神经元和星形胶质细胞的细胞生命和死亡决定很重要，而且对于神经元活性的关键调节剂也很重要。代谢如何改变脑活动的一个了不起的例子是对癫痫发作表现出的强烈抗药性，因为它具有缺失或变化不良的癫痫发作，这是一种Bcl-2家族蛋白，该蛋白会对葡萄糖和酮体消耗产生相互影响，独立于其调节细胞凋亡的能力。我们发现，BAD的代谢功能的改变会导致葡萄糖的线粒体氧化和神经元和星形胶质细胞中酮体的氧化增强。与用生酮饮食治疗的动物类似，这些代谢变化的不良突变小鼠表明，化学螺旋桨诱导的行为和电学癫痫发作具有惊人的抵抗力。遗传学和电生理研究还表明，不良中的这些相同的突变增加了ATP敏感钾（KATP）通道的开放概率，并且这些通道的激活是这种代谢诱导的癫痫发作耐药性中必要的中间体。我们提出的研究解决了有关不良新陈代谢和神经元兴奋性的机制的两个关键问题。第一个问题是燃料利用的代谢途径的水平：在修改不良时，葡萄糖和酮体代谢的确切步骤是什么？靶向代谢组学和13C追踪将与对坏的遗传操纵一起使用，以专门学习如何通过不同的代谢途径路由葡萄糖和酮体，以及该路由如何受到培养的神经元和星形胶质细胞以及大脑切片的影响。第二，不良突变神经元中KATP通道激活的可能原因和后果是什么？我们将利用荧光生物传感器评估在培养或切片中单个神经元和星形胶质细胞中的关键代谢信号 - ATP，ROS/谷胱甘肽氧化还原和NADH氧化还原的水平，以学习KATP通道激活的原因。互补的电生理研究将解决牙齿颗粒神经元中牙齿颗粒神经元中的兴奋性和信号传导的改变。这些问题的答案应为连接不良和燃料代谢的途径与神经元兴奋性改变的途径进行整合。了解这一途径应产生有价值的线索，以将这种有效的抗惊厥作用转化为对许多顽固性癫痫的人的改进疗法。