CILIARY NEUROTROPHIC FACTOR ENHANCES THE RATE OF OLIGODENDROCYTE GENERATION

Although ciliary neurotrophic factor (CNTF) is a potent survival facto r for many types of neurons and glial cells in vitro, there is current ly no evidence that it participates in normal development. Here we sho w that CNTF greatly enhances the rate of oligodendrocyte generation. P roliferation of oligodendrocyte precursor cells purified from rodent o ptic nerves and cultured in platelet-derived growth factor-containing medium is significantly increased by CNTF. Similarly, the number of pr oliferating oligodendrocyte precursor cells in developing optic nerves of transgenic mice lacking CNTF is decreased by up to threefold and t he number of oligodendrocytes is transiently decreased; proliferation is restored to normal by the delivery of exogenous CNTF into the devel oping optic nerve. Both oligodendrocyte number and myelination ultimat ely attain wild-type values in CNTF-deficient adult mice, indicating t hat CNTF is not necessary for either oligodendrocyte differentiation o r myelination, although it normally accelerates oligodendrocyte develo pment by enhancing the proliferation of oligodendrocyte precursor cell s.