Myelin is repaired by constitutive differentiation of oligodendrocyte progenitors

Oligodendrocytes form myelin sheaths around axons to enable rapid signaling within neural circuits. The generation of new oligodendrocytes through differentiation of oligodendrocyte precursor cells (OPCs) promotes myelin plasticity and repair in the adult brain. Here, we performed genetic interrogation and in vivo analysis of OPCs in order to determine their differentiation dynamics. Our results show that OPCs attempt to differentiate throughout the adult CNS with spatial and temporal regularity. The differentiation rate was not influenced by myelin demand or oligodendrocyte loss, and declined with age and in response to acute inflammation. The results suggest that OPC differentiation is governed primarily by constitutive processes and might be negatively influenced by aging and inflammation.