美国约翰霍普金斯大学Bergles, Dwight E.团队的最新研究探明了轴突的柔性鞘层使复杂中枢神经系统网络的髓鞘形成成为可能。该项研究成果发表在2026年4月1日出版的《自然》上。

在这里，研究团队发现斑马鱼和小鼠的轴突鞘鞘形成过程沿轴突以不同的速率进行。这使得单个少突胶质过程在成鞘前延伸过轴突分支点和Ranvier节点，从而形成由薄细胞质过程连接的髓鞘链。在大脑皮层中，这些“旁神经桥”扩展了单个少突胶质细胞沿小白蛋白中间神经元高度分支的轴突产生的髓鞘区域。尽管灵活的鞘层减少了对少突胶质细胞的需求，但髓磷脂链的末端鞘在衰老的大脑中更频繁地退化，这表明它们更容易受到细胞和环境压力的影响，并不成比例地导致髓磷脂损失。

研究人员表示，髓鞘由中枢神经系统（CNS）的少突胶质细胞形成，对神经回路功能和神经健康至关重要。这些绝缘鞘的分布在大脑区域、神经元亚型和单个轴突之间有很大的差异，但控制这种模式的机制尚不清楚。尽管先前的研究表明，每个少突胶质细胞过程产生一个单一的髓鞘，但这种轴突嵌套模式严重限制了复杂回路中沿高度分支的轴突的髓鞘形成。

附：英文原文

Title: Flexible ensheathment of axons enables myelination of complex CNS networks

Author: Call, Cody L., Neely, Sarah A., Early, Jason J., James, Owen G., Zoupi, Lida, Williams, Anna C., Xu, Yu Kang T., Chandran, Siddharthan, Lyons, David A., Monk, Kelly R., Bergles, Dwight E.

Issue&Volume: 2026-04-01

Abstract: Myelin sheaths made by oligodendrocytes in the central nervous system (CNS) are critical to circuit function and neural health. The distribution of these insulating sheaths varies substantially between brain regions1, neuron subtypes2 and individual axons3,4,5, but the mechanisms that control this patterning are poorly understood. Although previous studies suggested that each oligodendrocyte process generates a single myelin sheath, this mode of axon ensheathment severely constrains myelination along highly branched axons within complex circuits6. Here we find that axon ensheathment by individual myelinating processes in zebrafish and mouse proceeds at different rates along axons. This enables a single oligodendrocyte process to extend past axon branch points and nodes of Ranvier before ensheathment, resulting in the formation of chains of myelin sheaths connected by thin cytoplasmic processes. In the cerebral cortex, these ‘paranodal bridges’ expand the myelin territory produced by individual oligodendrocytes along the highly branched axons of parvalbumin interneurons. Although flexible ensheathment reduces the need for oligodendrocytes, terminal sheaths in myelin chains degenerated more frequently in the aged brain, suggesting that they are more vulnerable to cellular and environmental stress and disproportionally contribute to myelin loss.

DOI: 10.1038/s41586-026-10312-1

Source: https://www.nature.com/articles/s41586-026-10312-1