Inserm-Avenir Team, Mediterranean Institute of Neurobiology, Inmed, 13273 Marseille, France.
J Neurosci. 2010 Jan 13;30(2):785-96. doi: 10.1523/JNEUROSCI.5411-09.2010.
Embryonic motoneurons from mutant SOD1 (mSOD1) mouse models of amyotrophic lateral sclerosis (ALS), but not wild-type motoneurons, can be triggered to die by exposure to nitric oxide (NO), leading to activation of a motoneuron-specific signaling pathway downstream of the death receptor Fas/CD95. To identify effectors of mSOD1-dependent cell death, we performed a proteomic analysis. Treatment of cultured mSOD1 motoneurons with NO led to a 2.5-fold increase in levels of collapsin response mediator protein 4a (CRMP4a). In vivo, the percentage of mSOD1 lumbar motoneurons expressing CRMP4 in mSOD1 mice increased progressively from presymptomatic to early-onset stages, reaching a maximum of 25%. Forced adeno-associated virus (AAV)-mediated expression of CRMP4a in wild-type motoneurons in vitro triggered a process of axonal degeneration and cell death affecting 60% of motoneurons, whereas silencing of CRMP4a in mSOD1 motoneurons protected them from NO-induced death. In vivo, AAV-mediated overexpression of CRMP4a but not CRMP2 led to the death of 30% of the lumbar motoneurons and an 18% increase in denervation of neuromuscular junctions in the gastrocnemius muscle. Our data identify CRMP4a as a potential early effector in the neurodegenerative process in ALS.
胚胎运动神经元从肌萎缩侧索硬化症（ALS）的突变 SOD1（mSOD1）小鼠模型，但不是野生型运动神经元，可以通过暴露于一氧化氮（NO）来触发死亡，导致死亡受体 Fas/CD95 下游的运动神经元特异性信号通路的激活。为了鉴定 mSOD1 依赖性细胞死亡的效应物，我们进行了蛋白质组学分析。用 NO 处理培养的 mSOD1 运动神经元会导致 collapsin 反应介质蛋白 4a（CRMP4a）的水平增加 2.5 倍。在体内，mSOD1 小鼠中表达 CRMP4 的 mSOD1 腰椎运动神经元的百分比从无症状前到早发阶段逐渐增加，达到最大值 25%。体外，在野生型运动神经元中强制腺相关病毒（AAV）介导的 CRMP4a 表达触发了影响 60%运动神经元的轴突退化和细胞死亡过程，而在 mSOD1 运动神经元中沉默 CRMP4a 可保护它们免受 NO 诱导的死亡。在体内，AAV 介导的 CRMP4a 过表达而不是 CRMP2 过表达导致 30%的腰椎运动神经元死亡和腓肠肌神经肌肉接头去神经支配增加 18%。我们的数据将 CRMP4a 鉴定为 ALS 神经退行性过程中的潜在早期效应物。
