Migration of oligodendrocyte precursors on astrocytes and meningeal cells.

Oligodendrocytes populate developing white matter and repopulate demyelinated regions of the CNS by migration. Although little is known about their migratory routes, the environment through which these cells migrate, whether during development, disease, or injury, is packed with astrocytes infiltrated with or bounded by meningeal cells. In the present study, the migration of oligodendrocyte precursors from primary cultures and of the precursor cell lines (CG4 and Oli-neu) on astrocytes and meningeal cells was investigated using tissue culture migration assays and time lapse video microscopy. Oligodendrocyte precursors and the cell lines were found to migrate poorly on astrocytes and meningeal cells compared to migration on laminin even though both astrocytes and meningeal cells express cell surface laminin. The migration-inhibitory activity was not detected in conditioned media derived from either astrocytes or meningeal cells, nor was it detected from matrix deposited by these cells. Analyses of the events immediately following cell-cell contacts revealed that oligodendrocyte precursor-astrocyte contacts were typically long-lasting and appeared to be adhesive, whereas precursor-meningeal cell contacts usually resulted in rapid withdrawal of the precursor cell process. No correlation was found, however, between general adhesiveness and the rate of migration. Our results suggest that both astrocytes and meningeal cells retard migration of oligodendrocyte precursors, consistent with the view that they may impede the movement of oligodendrocyte precursors into CNS lesion sites.