Individual neuronal subtypes control initial myelin sheath growth and stabilization

Neural Development

Erin N. Eggum¹  James R. Gronseth¹  Madeline R. Martell¹  Samantha T. Maas¹  Silas Bergen¹  Amanda J. Kaiser¹  Allie G. Trudel¹  Heather N. Nelson¹  Anthony J. Treichel¹  Jacob H. Hines¹ 

[1] Biology Department, Winona State University, Winona, MN, USA;

关键词: Glia;    Oligodendrocyte;    Myelination;    Myelin sheath;   

DOI  :  10.1186/s13064-020-00149-3

来源: Springer

【 摘 要 】

BackgroundIn the developing central nervous system, pre-myelinating oligodendrocytes sample candidate nerve axons by extending and retracting process extensions. Some contacts stabilize, leading to the initiation of axon wrapping, nascent myelin sheath formation, concentric wrapping and sheath elongation, and sheath stabilization or pruning by oligodendrocytes. Although axonal signals influence the overall process of myelination, the precise oligodendrocyte behaviors that require signaling from axons are not completely understood. In this study, we investigated whether oligodendrocyte behaviors during the early events of myelination are mediated by an oligodendrocyte-intrinsic myelination program or are over-ridden by axonal factors.MethodsTo address this, we utilized in vivo time-lapse imaging in embryonic and larval zebrafish spinal cord during the initial hours and days of axon wrapping and myelination. Transgenic reporter lines marked individual axon subtypes or oligodendrocyte membranes.ResultsIn the larval zebrafish spinal cord, individual axon subtypes supported distinct nascent sheath growth rates and stabilization frequencies. Oligodendrocytes ensheathed individual axon subtypes at different rates during a two-day period after initial axon wrapping. When descending reticulospinal axons were ablated, local spinal axons supported a constant ensheathment rate despite the increased ratio of oligodendrocytes to target axons.ConclusionWe conclude that properties of individual axon subtypes instruct oligodendrocyte behaviors during initial stages of myelination by differentially controlling nascent sheath growth and stabilization.

【 授权许可】

CC BY