The Initial Myelination in the Central Nervous System

Myelination contributes not only to the rapid nerve conduction but also to axonal insulation and protection. In the central nervous system (CNS), the initial myelination features a multistep process where oligodendrocyte precursor cells undergo proliferation and migration before differentiating into mature oligodendrocytes. Mature oligodendrocytes then extend processes and wrap around axons to form the multilayered myelin sheath. These steps are tightly regulated by various cellular and molecular mechanisms, such as transcription factors (Olig family, Sox family), growth factors (PDGF, BDNF, FGF-2, IGF), chemokines/cytokines (TGF-beta, IL-1 beta, TNF alpha, IL-6, IFN-gamma), hormones (T3), axonal signals (PSA-NCAM, L1-CAM, LINGO-1, neural activity), and intracellular signaling pathways (Wnt/beta-catenin, PI3 K/AKT/mTOR, ERK/MAPK). However, the fundamental mechanisms for initial myelination are yet to be fully elucidated. Identifying pivotal mechanisms for myelination onset, development, and repair will become the focus of future studies. This review focuses on the current understanding of how CNS myelination is initiated and also the regulatory mechanisms underlying the process.

Automated summary

Myelination is important for rapid nerve conduction, axonal insulation, and protection. The process involves the proliferation, migration, and differentiation of oligodendrocyte precursor cells, followed by the extension of mature oligodendrocytes and the formation of the myelin sheath around axons. Various cellular and molecular mechanisms regulate these steps, including transcription factors, growth factors, chemokines/cytokines, hormones, axonal signals, and intracellular signaling pathways. However, the precise mechanisms for initial myelination are still not fully understood. Future studies will focus on identifying the key mechanisms for myelination onset, development, and repair.