The Axonal Glycolytic Pathway Contributes to Sensory Axon Extension and Growth Cone Dynamics
The Axonal Glycolytic Pathway Contributes to Sensory Axon Extension and Growth Cone Dynamics
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DOI：
10.1523/jneurosci.0321-21.2021
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发表时间：
2021-08-04
影响因子：
5.3
通讯作者：
Gallo, Gianluca
中科院分区：
文献类型：
--
作者：
Ketschek, Andrea;Sainath, Rajiv;Gallo, Gianluca
了解轴突延伸和维持的生物能量学对神经发育和疾病状态具有广泛的意义。糖酵解是一个由10种酶组成的途径，分为准备阶段和支付阶段，后者产生ATP。利用胚胎鸡感觉神经元，我们报道在轴突和生长锥中发现糖酵解酶。在NGF存在的情况下，糖酵解的药理抑制会在几分钟内损害轴突的延伸和生长锥动力学，而不影响轴突的维持。微流控室实验表明，抑制糖酵解对轴突延伸的影响是局部的，沿远端轴突延伸，可以通过促进线粒体呼吸来逆转。GAPDH的敲低简化了生长锥的形态，并通过shrna抗性GAPDH的表达得以挽救。使用KillerRed与GAPDH融合，然后在远端轴突局部发色团辅助光灭活KillerRed-GAPDH，可以阻止生长锥动力学。考虑到丝聚合需要ATP，抑制糖酵解导致轴突肌动蛋白丝水平的矛盾增加。对肌动蛋白丝的影响是由于GAPDH之前的酶，这是收获期的第一个酶。在缺乏NGF的情况下，沿远端轴突的糖酵解抑制导致轴突变性，而不依赖于细胞死亡。这些数据表明，糖酵解途径在远端轴突起作用，并有助于在NGF存在时轴突延伸速率和生长锥动力学，并且在缺乏NGF的情况下，轴突糖酵解途径是维持轴突的必要条件。
Understanding the bioenergetics of axon extension and maintenance has wide ranging implications for neurodevelopment and disease states. Glycolysis is a pathway consisting of 10 enzymes and separated into preparatory and payoff phases, the latter producing ATP. Using embryonic chicken sensory neurons, we report that glycolytic enzymes are found through the axon and the growth cone. Pharmacological inhibition of glycolysis in the presence of NGF impairs axon extension and growth cone dynamics within minutes without affecting axon maintenance. Experiments using microfluidic chambers show that the effect of inhibiting glycolysis on axon extension is local along distal axons and can be reversed by promoting mitochondrial respiration. Knockdown of GAPDH simplifies growth cone morphology and is rescued by shRNA-resistant GAPDH expression. Rescue of GAPDH using KillerRed fused to GAPDH followed by localized chromophore-assisted light inactivation of KillerRed-GAPDH in distal axons halts growth cone dynamics. Considering filament polymerization requires ATP, inhibition of glycolysis results in a paradoxical increase in axonal actin filament levels. The effect on actin filaments is because of enzymes before GAPDH, the first enzyme in the payoff phase. In the absence of NGF, inhibition of glycolysis along distal axons results in axon degeneration independent of cell death. These data indicate that the glycolytic pathway is operative in distal axons and contributes to the rate of axon extension and growth cone dynamics in the presence of NGF and that, in the absence of NGF, the axonal glycolytic pathway is required for axon maintenance.