Oligodendrocyte progenitor cell

Oligodendrocyte progenitor cells (OPCs), also known as oligodendrocyte precursor cells, NG2-glia, O2A cells, or polydendrocytes, are a subtype of glia in the central nervous system named for their essential role as precursors to oligodendrocytes and myelin. They are typically identified in the human by co-expression of PDGFRA and CSPG4.

OPCs play a critical role in developmental and adult myelinogenesis. They give rise to oligodendrocytes, which then wrap around axons and provide electrical insulation by forming a myelin sheath. This enables faster action potential propagation and high fidelity transmission without a need for an increase in axonal diameter. The loss or lack of OPCs, and consequent lack of differentiated oligodendrocytes, is associated with a loss of myelination and subsequent impairment of neurological functions. In addition, OPCs express receptors for various neurotransmitters and undergo membrane depolarization when they receive synaptic inputs from neurons.

Structure

OPCs are glial cells that are typically identified by co-expression of NG2 (a chondroitin sulfate proteoglycan encoded by CSPG4 in humans) and platelet-derived growth factor receptor alpha (encoded by PDGFRA). They are smaller than neurons, of comparable size to other glia, and can either have a bipolar or complex multipolar morphology with processes reaching up to ~50 μm. OPCs comprise approximately 3–4% of cells in grey matter and 8–9% in white matter, making them the fourth largest group of glia after astrocytes, microglia and oligodendrocytes.