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: 8558405
• 负责人: Nika N Danial
• 金额: $ 35.31万
• 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/8558405
• 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）：通过燃料底物转换对神经元活性进行代谢控制。燃料代谢不仅对脑中神经元和星形胶质细胞的细胞生死决定很重要，而且作为神经元活动的关键调节器也很重要。代谢如何改变大脑活动的一个显著例子是BAD缺失或改变的小鼠表现出对癫痫发作的强烈抵抗力，BAD是一种BCL-2家族蛋白，其对葡萄糖和酮体消耗产生相互作用，而不依赖于其调节细胞凋亡的能力。我们发现BAD代谢功能的改变可导致神经元和星形胶质细胞中葡萄糖的线粒体氧化减少和酮体氧化增强。与生酮饮食处理的动物相似，具有这些代谢变化的BAD突变小鼠对化学促惊厥剂诱导的行为和电图癫痫发作表现出惊人的抵抗力。遗传和电生理学研究还表明，BAD中的这些相同突变增加了ATP敏感性钾（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抗性的必要中间体。我们提出的研究解决了关于BAD改变代谢和神经元兴奋性的机制的两个关键问题。第一个问题是在燃料利用的代谢途径水平上：当BAD被修饰时，葡萄糖和酮体的代谢发生变化的确切步骤是什么？靶向代谢组学和13 C示踪将与BAD的遗传操作结合使用，以具体了解葡萄糖和酮体如何通过不同的代谢途径进行路由，以及这种路由如何受到BAD的影响，在培养的神经元和星形胶质细胞以及脑切片中。第二，BAD突变神经元中KATP通道激活的可能原因和后果是什么？我们将采用荧光生物传感器来评估培养或切片中单个神经元和星形胶质细胞中关键代谢信号- ATP，ROS/谷胱甘肽氧化还原和NADH氧化还原的水平，以了解KATP通道激活的原因。补充电生理学研究将解决如何在BAD突变体脑切片中改变齿状颗粒神经元的兴奋性和信号传导。这些问题的答案应该给出一个完整的图片的途径连接BAD和燃料代谢与改变神经元兴奋性。了解这一途径应该产生有价值的线索，将这种有效的抗惊厥代谢作用转化为改善许多难治性癫痫患者的治疗方法。