Myelinogenic Plasticity of Oligodendrocyte Precursor Cells following Spinal Cord Contusion Injury

Spontaneous remyelination occurs after spinal cord injury (SCI), but the extent of myelin repair and identity of the cells responsible remain incompletely understood and contentious. We assessed the cellular origin of new myelin by fate mapping platelet-derived growth factor receptor alpha (PDGFR alpha), Olig2+, and P0+ cells following contusion SCI in mice. Oligodendrocyte precursor cells (OPCs; PDGFR alpha+) produced oligodendrocytes responsible for de novo ensheathment of similar to 30% of myelinated spinal axons at injury epicenter 3 months after SCI, demonstrating that these resident cells are a major contributor to oligodendrocyte regeneration. OPCs also produced the majority of myelinating Schwann cells in the injured spinal cord; invasion of peripheral myelinating (P0+) Schwann cells made only a limited contribution. These findings reveal that PDGFR alpha+ cells perform diverse roles in CNS repair, as multi-potential progenitors that generate both classes of myelinating cells. This endogenous repair might be exploited as a therapeutic target for CNS trauma and disease.