Developmental Neuroscience 23:4-5:2001,
327-337.
Song-Kyu Park, David Solomon, Timothy
Vartanian
Department of Neurology, Beth Israel
Deaconess Medical Center, Program in Neuroscience, Harvard Medical School,
Boston, Mass., USA
Abstract
The molecular signals required for
initiating myelination and maintenance of the myelin internode are not
known.
Several growth factor families have
been implicated in promoting oligodendrocyte survival or differentiation
and may have consequences on formation of myelin.
We developed a reliable assay for
detecting ensheathment of neurites by oligodendrocytes in spinal cord explants.
This system was used to assay the
effect of selected growth factors on myelin internode formation.
We examined the influence on myelination
of the polypeptide growth factors neuregulin (NRG), platelet-derived growth
factor (PDGF), leukemia inhibitory factor (LIF), and the thyroid hormone
T3.
We found that NRG, PDGF, and T3 treatments
enhanced myelination while LIF treatment inhibited it.
We furthermore found that the most
potent combination of factors to enhance myelination was NRG and T3.
Our results demonstrate that the
role of growth factors on CNS myelination can be reliably studied in a
controlled in vitro environment and that the impact of individual or combinations
of growth factors on myelination cannot be predicted by their known effects
on oligodendrocyte survival, proliferation, or differentiation.
Copyright © 2001 S. Karger AG,
Basel