The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA.
Johns Hopkins University, Kavli Neuroscience Discovery Institute, Baltimore, MD, USA.
Nat Commun. 2021 Aug 6;12(1):4767. doi: 10.1038/s41467-021-25035-2.
Axons in the cerebral cortex show a broad range of myelin coverage. Oligodendrocytes establish this pattern by selecting a cohort of axons for myelination; however, the distribution of myelin on distinct neurons and extent of internode replacement after demyelination remain to be defined. Here we show that myelination patterns of seven distinct neuron subtypes in somatosensory cortex are influenced by both axon diameter and neuronal identity. Preference for myelination of parvalbumin interneurons was preserved between cortical areas with varying myelin density, suggesting that regional differences in myelin abundance arises through local control of oligodendrogenesis. By imaging loss and regeneration of myelin sheaths in vivo we show that myelin distribution on individual axons was altered but overall myelin content on distinct neuron subtypes was restored. Our findings suggest that local changes in myelination are tolerated, allowing regenerated oligodendrocytes to restore myelin content on distinct neurons through opportunistic selection of axons.
大脑皮层中的轴突表现出广泛的髓鞘覆盖范围。少突胶质细胞通过选择一组轴突进行髓鞘形成来建立这种模式；然而，髓鞘在不同神经元上的分布以及脱髓鞘后节间段的替换程度仍有待确定。在这里，我们表明感觉皮层中七种不同神经元亚型的髓鞘形成模式受到轴突直径和神经元身份的影响。在髓鞘密度不同的皮质区域之间，钙结合蛋白阳性中间神经元的髓鞘形成偏好得以保留，这表明髓鞘丰度的区域差异是通过少突胶质细胞发生的局部控制产生的。通过在体成像观察到髓鞘鞘的丢失和再生，我们发现单个轴突上的髓鞘分布发生了改变，但不同神经元亚型的总体髓鞘含量得以恢复。我们的研究结果表明，髓鞘的局部变化是可以耐受的，允许再生的少突胶质细胞通过轴突的机会性选择，在不同神经元上恢复髓鞘含量。
