Iron modulates the differentiation of a distinct population of glial precursor cells into oligodendrocytes

Iron deficiency in children is associated with a number of neural defects i ncluding hypomyelination. It has been hypothesized by others that this hypo myelination is due to a failure in myelin production. Other possibilities i nclude failure in the generation of oligodendrocytes from their precursor c ells or an interruption in oligodendrocyte maturation. These hypotheses are based on the observations that there is a peak in brain iron uptake in viv o that coincides with the period of greatest myelination and that a shortag e of iron leads to myelination deficiency. We now demonstrate that iron ava ilability modulates the generation of oligodendrocytes from tripotential-gl ial restricted precursor (GRP) cells isolated front the embryonic day 13.5 rat spinal cord. In contrast, we found no effects of iron on oligodendrocyt e maturation or survival in vitro, nor did we find that increasing iron ava ilability above basal levels increases oligodendrocyte generation from bipo tential oligodendrocyte-type-2 astrocyte/oligodendrocyte precursor cells (O -2A/OPCs). Our results raise the possibility that iron may affect oligodend rocyte development at stages during early embryogenesis rather than during later development. (C) 2001 Academic Press.