The L2/HNK-1 carbohydrate is preferentially expressed by previously motor axon-associated Schwann cells in reinnervated peripheral nerves
The L2/HNK-1 carbohydrate is preferentially expressed by previously motor axon-associated Schwann cells in reinnervated peripheral nerves
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DOI：
10.1523/jneurosci.14-11-07180.1994
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发表时间：
1994-11
期刊：
影响因子：
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通讯作者：
Rudolf Martini;M. Schachner;T. Brushart
中科院分区：
文献类型：
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作者：
Rudolf Martini;M. Schachner;T. Brushart
碳水化合物表位L2/HNK-1（下文称为L2）在成年小鼠中通过腹根和肌肉神经的髓鞘化雪旺细胞表达，但很少通过背根或皮肤神经的髓鞘化雪旺细胞表达。由于底物包被的L2糖脂促进培养的运动神经元而不是感觉神经元的生长，因此L2可能通过在体内再生运动轴突来影响肌肉神经的优先再支配。在本研究中，我们分析了再生轴突对L2表达的影响，通过将运动或感觉轴突定向到8周龄小鼠股神经的肌肉和皮肤分支，重新支配雪旺细胞。我们观察到，从皮肤分支再生轴突不会导致免疫细胞化学检测到的L2表达在肌肉或皮肤神经分支。从肌分支再生的轴突导致皮肤分支的少数雪旺细胞弱表达L2，但引起肌分支的许多雪旺细胞强表达L2。因此，以前与运动轴突相关的髓鞘化雪旺细胞与以前与感觉轴突相关的髓鞘化雪旺细胞在与运动轴突接触时表达L2的能力不同。在神经再支配的关键阶段L2表达的这种上调可以提供再生到适当的肌肉通路中的运动轴突，其具有优于再生到不适当的感觉通路中的那些运动轴突的优势。
The carbohydrate epitope L2/HNK-1 (hereafter designated L2) is expressed in the adult mouse by myelinating Schwann cells of ventral roots and muscle nerves, but rarely by those of dorsal roots or cutaneous nerves. Since substrate-coated L2 glycolipids promote outgrowth of cultured motor but not sensory neurons, L2 may thus influence the preferential reinnervation of muscle nerves by regenerating motor axons in vivo. In the present study, we have analyzed the influence of regenerating axons on L2 expression by reinnervated Schwann cells by directing motor or sensory axons into the muscle and cutaneous branches of femoral nerves of 8-week-old mice. We observed that regenerating axons from cutaneous branches did not lead to immunocytochemically detectable L2 expression in muscle or cutaneous nerve branches. Axons regenerating from muscle branches led to a weak L2 expression by few Schwann cells of the cutaneous branch, but provoked a strong L2 expression by many Schwann cells of the muscle branch. Myelinating Schwann cells previously associated with motor axons thus differed from previously sensory axon-associated myelinating Schwann cells in their ability to express L2 when contacted by motor axons. This upregulation of L2 expression during critical stages of reinnervation may provide motor axons regenerating into the appropriate, muscle pathways with an advantage over those regenerating into the inappropriate, sensory pathways.