Preserving Inhibitory Cortical Networks Following TBI: Attenuating Excitation Using Inhibitors of Glycolysis

项目总结 创伤性脑损伤是导致儿童和老年人死亡和残疾的主要原因。认知 运动功能障碍，以及创伤后癫痫(PTE)，通常发生在脑外伤后。有有限的 脑外伤的治疗选择，没有一种被证明在改善神经预后方面有效 横跨不同的脑外伤患者群体。因此，开发基于机械学的新的治疗工具 基本原理对于寻找治疗方法以改善脑外伤后患者的预后至关重要。最近，我们报道了， 脑损伤受控皮质撞击(CCI)模型导致小白蛋白阳性抑制显著丧失 大脑皮层的中间神经元。小白蛋白阳性的中间神经元提供大量的皮质抑制， 抑制神经元活动。当脑外伤后小白蛋白阳性中间神经元丢失时，未加控制 谷氨酸能活动随着兴奋性突触输入的增加和抑制性突触输入的减少而增加。 基于这些发现，我们着手开发脑外伤后保护中间神经元的方法。基于 已发表的数据显示脑外伤后脑内糖酵解活动增强的区域，以及已知的联系 在糖酵解和神经元活动之间，我们开始确定脑外伤后抑制糖酵解是否会 减轻小白蛋白中间神经元的丢失。我们假设脑外伤会导致糖酵解依赖 兴奋性神经元活性增加。这将导致抑制性中间神经元和它们的 随后的兴奋性毒性细胞死亡。我们建议中断糖酵解以减弱兴奋性神经元的活动。 跟随着TBI。使用己糖激酶(糖酵解的限速酶)的抑制剂2-脱氧葡萄糖(2DG)， 我们已经开始检验这一假设。我们的初步数据表明，2DG可以显著减弱皮质 颅脑损伤后2~4周脑片的超兴奋性及2DG体内治疗的研究 减轻网络过度兴奋和小白蛋白阳性细胞丢失。我们的初步数据也 提示2DG可减弱兴奋性神经元兴奋性，但不能抑制神经元兴奋性。在此，我们建议进一步 这些研究表明，2DG减少了小白蛋白阳性中间神经元细胞的死亡，并减少了 损伤后大脑皮质突触通讯的变化。我们还建议检验这一假设 抑制糖酵解可以减弱兴奋性，但不能抑制细胞的兴奋性。此外，我们的目标是 确定兴奋性神经元中糖酵解及相关蛋白的表达是否存在差异。 单细胞定量聚合酶链式反应抑制中间神经元。该提案的这一方面既有高风险，也有高回报。 我们的研究将确定2DG是否能够保护脑损伤后的中间神经元，将开始建立2DG 作用机制，并可能展示一种新的形式的细胞类型特定的代谢偶联 和电活动。基于这些研究，我们将能够更好地操纵神经元的兴奋性 针对特定细胞类型的代谢干扰，并设计治疗策略，以减少脑损伤相关的病理改变。

Project summary Traumatic brain injuries (TBI) are the leading cause of death and disability in children and the aged. Cognitive and motor dysfunction, as well as post-traumatic epilepsy (PTE), often occurs following TBI. There are limited therapeutic options for TBI, none of which have proven to be efficacious in improving neurological outcomes across diverse groups of TBI patients. Therefore, developing new therapeutic tools based on mechanistic rationale are critical to finding treatments to improve patient outcome following TBI. Recently, we reported that the controlled cortical impact (CCI) model of TBI resulted in a significant loss of parvalbumin-positive inhibitory interneurons in the cortex. Parvalbumin-positive interneurons provide a bulk of cortical inhibition which constrains neuronal activity. When parvalbumin-positive interneurons were lost following TBI, uncontrolled glutamatergic activity was seen along with increased excitatory and decreased inhibitory synaptic inputs. Based on these findings, we set out to develop approaches to preserve interneurons following TBI. Based on published data showing areas of increased glycolytic activity in the brain following TBI, and known linkages between glycolysis and neuronal activity, we set out to determine if inhibiting glycolysis following TBI would attenuate loss of parvalbumin interneurons. We hypothesized that TBI leads to glycolysis-dependent increases in excitatory neuron activity. This would lead to hyper-activation of inhibitory interneurons and their subsequent excitotoxic cell death. We propose to interrupt glycolysis to attenuate excitatory neuronal activity following TBI. Using 2-deoxyglucose (2DG), an inhibitor of hexokinase (the rate-limiting enzyme of glycolysis), we have begun to test this hypothesis. Our preliminary data suggests that 2DG can acutely attenuate cortical hyperexcitability in brain slices 2-4 weeks following TBI and that in vivo treatment with 2DG following TBI attenuates both network hyperexcitability and parvalbumin-positive cell loss. Our preliminary data also suggests that 2DG attenuates excitatory, but not inhibitory, neuron excitability. Here we propose to further these studies by demonstrating that 2DG reduces parvalbumin-positive interneuron cell death and reduces changes in synaptic communication in the cortex following injury. We also propose to test the hypothesis that inhibition of glycolysis attenuates excitatory, but not inhibitory, cell excitability. Furthermore, we aim to determine whether there is differential expression of glycolytic and related proteins in excitatory neurons vs. inhibitory interneurons via single-cell qPCR. This aspect of the proposal is both high-risk and high-reward. Our studies will determine if 2DG is able to preserve interneurons following TBI, will begin to establish 2DG's mechanism of action, and will potentially demonstrate a novel form of cell type-specific coupling of metabolic and electrical activity. Based on these studies, we will be better able to manipulate neuronal excitability with cell type-specific metabolic disruption and to design therapeutic strategies to reduce TBI-associated pathology.