AMPK, metabolism and ALS

 描述(申请人提供)：所有神经退行性疾病(NDG)都表现为线粒体功能障碍，这可以通过降低细胞内AMP/ATP比率或通过产生活性氧来激活AMP激活的蛋白激酶(AMPK)。活性AMPK通过抑制分解代谢和刺激合成代谢过程重新连接细胞新陈代谢。虽然直觉上激活的AMPK应该对神经元是健康的，但在几个NDG模型中，AMPK的激活被证明对神经元是有害的。本研究旨在探讨肌萎缩侧索硬化症(ALS)细胞模型中神经元AMPK活性受损的机制。表达突变的SOD或TDP43的神经元(用来模拟ALS)由于AMPK的激活而增强了糖酵解。在特定目的#1的实验验证了这样的假设：通过转移糖酵解底物远离己糖胺生物合成和戊糖磷酸途径-维持健康的氧化还原状态和抑制未折叠的蛋白质反应的关键途径-激活的AMPK对神经元有害。为了将这些观察转化为ALS患者的潜在治疗方法，我们需要能够特定地操纵神经元的糖酵解--因为抑制神经胶质细胞的糖酵解可能会产生不良影响。在特定的目标#2中，我们将使用转基因小鼠分别从神经元和神经胶质细胞中分离出核糖体，并询问相关的糖酵解酶的细胞类型特异性变体的mRNA。对于ALS患者中可能对新陈代谢靶向干预有反应的一组患者来说，在有毒蛋白质环境下重新连接新陈代谢可能是有报道的。在特定的目标#3中，我们将确定ALS患者和对照组重新编程为神经元的成纤维细胞中代谢重新连接的流行率。了解NDG对代谢应激的神经元特异性适应有可能为治疗干预发现新的靶点。

 DESCRIPTION (provided by applicant): All neurodegenerative diseases (NDG) display mitochondrial dysfunction and this can lead to activation of AMP activated protein kinase (AMPK) either through a reduced cellular AMP/ATP ratio or via the production of reactive oxygen species. Active AMPK re-wires cellular metabolism by inhibiting catabolic and stimulating anabolic processes. While intuitively activated AMPK ought to be healthful for neurons, in several NDG models AMPK activation has been shown to be noxious to neurons. This proposal aims to identify the mechanism by which activated AMPK in neurons is injurious in cellular models of Amyotrophic Lateral Sclerosis (ALS). Neurons expressing mutant SOD or TDP43 (to model ALS) have enhanced glycolysis as a function of AMPK activation. Experiments in Specific Aim #1 test the hypothesis that by diverting glycolytic substrates away from the hexosamine biosynthetic and the pentose phosphate pathways - key pathways for maintaining healthy redox state and suppressing the unfolded protein response - activated AMPK is noxious to neurons. To translate these observations into a potential therapy for ALS patients we need to be able to manipulate glycolysis in neurons specifically - since inhibition of glycolysis in glial cells could have adverse effects. In Specific Aim #2, we will use genetically modified mice to isolate ribosomes from neurons and glial cells separately and interrogate the associated mRNA for cell type specific variants of glycolytic enzymes. Rewiring metabolism in the setting of toxic proteins may be reporter for a subgroup of ALS patients that could respond to metabolism-targeted intervention. In Specific Aim #3, we will determine the prevalence of metabolic re-wiring in fibroblasts re-programmed into neurons from ALS patients and controls. Understanding the neuron-specific adaptation to metabolic stress in NDG has the potential to uncover new targets for therapeutic intervention.