A new player in the game: identification of C1ql1 as a novel factor driving OPC differentiation.

Oligodendrocytes (OLGs) are the myelin-producing cells in the central nervous system (CNS). Following injury, these cells are prone to death, leading to demyelination and, eventually, axonal loss and neurodegeneration. Upon injury, the damaged CNS repopulates the lesion with oligodendrocyte precursor cells (OPCs) that consequently mature into OLGs to repair the myelin damage and prevent further axonal loss. In this issue, Altunay et al. identified that complement component 1, q subcomponent-like-1 (C1ql1), a factor known to play a role in neuron-neuron synapses, is also expressed by OPCs and drives their differentiation into OLGs. These data suggest that C1ql1 or other downstream factors could be therapeutic targets in the context of demyelinating disorders in which remyelination fails, such as in multiple sclerosis (MS).