The reactions and role of NG2 glia in spinal cord injury

• The reactions of OPCs to spinal cord injury are reviewed.
• Inflammation after injury can affect OPC biology and OPC reactivity may affect the inflammatory response.
• OPC accumulation after spinal cord injury is detrimental to axon repair and regeneration.
• Opportunities for future research are discussed.

Oligodendrocyte precursor cells (OPCs) react rapidly to brain and spinal cord injuries. This reaction is characterized by the retraction of cell processes, cell body swelling and increased expression of the NG2 chondroitin sulfate proteoglycan. Reactive OPCs rapidly divide and accumulate surrounding the injury site where they become major cellular components of the glial scar. The glial reaction to injury is an attempt to restore normal homeostasis and re-establish the glia limitans but the exact role of reactive OPCs in these processes is not well understood. Traumatic injury results in extensive oligodendrocyte cell death and the proliferating OPCs generate the large number of precursor cells necessary for remyelination. Reactive OPCs, however, also are a source of axon-growth inhibitory proteoglycans and may interact with invading inflammatory cells in complex ways. Here, I discuss these and other properties of OPCs after spinal cord injury. Understanding the regulation of these disparate properties may lead to new therapeutic approaches to devastating injuries of the spinal cord.This article is part of a Special Issue entitled SI:NG2-glia(Invited only).