Astrocytes in myelination and remyelination

•Astrocytes contribute to myelination via gap junctions with oligodendrocytes, transfer of lipids and secretion of factors.•Astrocytes regulate remyelination by secretion of factors, cholesterol efflux, and recruitment of peripheral immune cells.•Astrocyte-microglia cross-talk occurs in development and following injury throughout the lifespan to regulate white matter health. Astrocytes are known to play critical roles in central nervous system development, homeostasis, and response to injury. In addition to well-defined functions in synaptic signalling and blood-brain barrier control, astrocytes are now emerging as important contributors to white matter health. Here, we review the roles of astrocytes in myelin formation and regeneration (remyelination), focusing on both direct interactions with oligodendrocyte lineage cells, and indirect influences via crosstalk with central nervous system resident macrophages, microglia.