Cellular mechanisms of dietary therapy for epilepsy

饮食治疗癫痫的细胞机制

• 批准号: 8575701
• 负责人: GARY I YELLEN
• 金额: $ 37.06万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-15 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8575701
• 关键词: 5' -AMP-activated protein kinase; ATP sensitive potassium channel complex; Action Potentials; Acute; Affect; Astrocytes; Behavior; Biosensor; Brain; Carbohydrates; Cells; Chemical Stimulation; Chemicals; Cytoplasmic Granules; Data; Diet; Disease; Dose; Educational process of instructing; Electric Stimulation; Electrodes; Electrophysiology (science); Energy Metabolism; Engineering; Epilepsy; Fatty Acids; Fatty acid glycerol esters; Gene Expression; Genetic Models; Glucose; Glutamates; Glutathione; Goals; Grant; Hippocampus (Brain); Image; Individual; Interneurons; Ketone Bodies; Ketones; Learning; Link; Measurement; Measures; Metabolic; Metabolism; Modeling; Monitor; Mus; NADH; NADP; Nerve Degeneration; Neurons; Oxidation-Reduction; Patients; Pharmaceutical Preparations; Pharmacotherapy; Play; Population; Probability; Production; Provider; Pyruvate; Reactive Oxygen Species; Relative (related person); Reporting; Resistance; Role; Seizures; Signal Transduction; Slice; Stimulus; Synapses; System; Therapeutic Effect; Translating; Traumatic Brain Injury; Work; analog; base; brain cell; cell type; cofactor; dentate gyrus; design; direct application; excitatory neuron; extracellular; insight; ketogenic diet; neuronal excitability; public health relevance; receptor; response

DESCRIPTION (provided by applicant): Our goal is to understand the mechanism of metabolically induced resistance to epileptic seizures. Epilepsy is extremely common, affecting on the order of 1% of the population, and about a third of people with epilesy are not well treated by existing medications. Dietary therapies such as the ketogenic diet can be very effective for such pharmacoresistant epilepsy, but the diets are often difficul for patients and providers. However, if we can understand the mechanism of the seizure resistance produced by these diets, it may be possible to find new medications to treat a wide range of currently poorly treated epilepsies. In the previous grant period, we found suppor for the hypothesis that ATP--sensitive potassium channels (KATP channels) are critical for metabolic seizure resistance. We observed that KATP channels in neurons could be activated synergistically by neuronal activity and by ketone bodies (which are an alternative fuel used by the brain on the ketogenic diet). We discovered a mouse genetic model for metabolic seizure resistance that does not require a change in diet and learned that in this model, KATP channels are required for the seizure resistance. We also engineered new fluorescent biosensors to detect intracellular changes of the key metabolic cofactors ATP and NADH, to enable a better understanding of cellular metabolism. Our first aim for this grant renewal is to learn how brain cell metabolism responds o the energy demands of stimulation and how those responses depend on different cellular fuels (such as the ketone bodies that become available to the brain on a ketogenic diet). Our own biosensors and others will be used to monitor the responses, in individual cells, of specific key metabolic signals: ATP, NADH, glutathione redox, and AMP-- activated protein kinase activity. Each of these signals not only reports on metabolism but also has effects on downstream mechanisms that affect neuronal excitability. We will study these responses in cultured hippocampal neurons, for which we have optimal control of extracellular fuels. We will also study acute brain slices, which will allow us to examine distinctive behavior i excitatory neurons, inhibitory interneurons, and nearby astrocytes, in response to either synaptic or electrical stimulation. These studies should provide an unprecedented view of metabolic responses in brain cells, and give fundamental insights into how neurons and astrocytes respond to energy demands. These insights will be valuable not only for understanding the basis of metabolic seizure resistance, but also for how brain cells respond to metabolic challenges in disorders ranging from traumatic brain injury to neurodegeneration. Our second aim is to link metabolic changes to KATP channel activity by learning how KATP channels respond to energy levels in intact neurons. We will record the ope probability of KATP channels simultaneously with biosensor measurements of [ATP] or ATP:ADP ratio, to learn the actual dose--response relation for intact neurons, and the conditions for engaging these channels to produce seizure resistance.

描述（由申请人提供）：我们的目标是了解代谢诱导的抗癫痫发作的机制。 癫痫症非常常见，影响了大约 1% 的人口，并且大约三分之一的癫痫患者无法通过现有药物得到很好的治疗。生酮饮食等饮食疗法对于此类耐药性癫痫非常有效，但这种饮食对于患者和提供者来说通常很困难。然而，如果我们能够了解这些饮食产生的癫痫抵抗机制，就有可能找到新的药物来治疗目前治疗效果不佳的多种癫痫症。 在之前的资助期间，我们发现了对 ATP 敏感钾通道（KATP 通道）对于代谢性癫痫抵抗至关重要的假设的支持。 我们观察到神经元中的 KATP 通道可以通过神经元活动和酮体（酮体是生酮饮食中大脑使用的替代燃料）协同激活。 我们发现了一种无需改变饮食即可抵抗代谢性癫痫发作的小鼠遗传模型，并了解到在该模型中，KATP 通道是抵抗癫痫发作所必需的。我们还设计了新型荧光生物传感器来检测关键代谢辅因子 ATP 和 NADH 的细胞内变化，以便更好地了解细胞代谢。 我们更新这笔赠款的首要目标是了解脑细胞新陈代谢如何对刺激的能量需求做出反应，以及这些反应如何依赖于不同的细胞燃料（例如生酮饮食中大脑可利用的酮体）。我们自己的生物传感器和其他生物传感器将用于监测单个细胞中特定关键代谢信号的反应：ATP、NADH、谷胱甘肽氧化还原和 AMP（激活的蛋白激酶活性）。 这些信号中的每一个不仅报告新陈代谢，还对影响神经元兴奋性的下游机制产生影响。 我们将在培养的海马神经元中研究这些反应，为此我们可以对细胞外燃料进行最佳控制。我们还将研究急性脑切片，这将使我们能够检查兴奋性神经元、抑制性中间神经元和附近星形胶质细胞对突触或电刺激的反应的独特行为。 这些研究应该提供一个前所未有的代谢观点 脑细胞的反应，并提供关于神经元和星形胶质细胞如何进行的基本见解 响应能源需求。 这些见解不仅对于理解很有价值 它是代谢性癫痫抵抗的基础，也是脑细胞如何应对从创伤性脑损伤到神经退行性疾病等疾病的代谢挑战的基础。 我们的第二个目标是通过了解 KATP 通道如何响应完整神经元的能量水平，将代谢变化与 KATP 通道活动联系起来。 我们将记录 KATP 通道的开放概率，同时生物传感器测量 [ATP] 或 ATP:ADP 比率，以了解完整神经元的实际剂量反应关系，以及利用这些通道产生癫痫抵抗的条件。