Journal of Neuroscience, Vol 12, 2751-2764, Copyright © 1992 by Society for Neuroscience
Astrocyte precursors in neonatal rat spinal cord cultures
J Fok-Seang and RH Miller
Department of Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
Cultures of newborn rat spinal cord contain multiple types of astrocytes.
By using a combination of cultures enriched for glial precursors and clonal
analysis, we have identified a particular astrocyte precursor that gives
rise to morphologically distinct classes of astrocytes. This astrocyte
precursor labels with the monoclonal antibody A2B5, is highly migratory,
proliferates in response to serum and platelet-derived growth factor, and
differentiates into process- bearing astrocytes, many of which subsequently
assume a "pancake"- shaped morphology. A2B5+ astrocyte precursors share
antigenic and migratory characteristics with previously described O2A
progenitor cells but differ in their response to regulatory factors,
including serum and coculture with type 1 astrocytes. More importantly,
these astrocyte precursors do not give rise to oligodendrocytes. In their
proliferative response to serum and their capacity to differentiate into
astrocytes, these glial precursors resemble type 1 astrocyte precursors
from optic nerve. However, unlike type 1 astrocyte precursors, these cells
are A2B5+, highly migratory, and do not give rise to fibroblast-like
astrocytes. Neonatal rat spinal cord cultures contain approximately twice
the number of the A2B5+ astrocyte precursors than O2A progenitor cells. By
contrast, the majority of A2B5+ cells in postnatal day 7 optic nerve
cultures are O2A progenitors. The presence of large numbers of A2B5+
astrocyte precursors in rat spinal cord cultures may reflect the more
complex cytoarchitecture of the spinal cord compared to the optic nerve.