Figure 2.

Axon growth-promoting properties of glial restricted precursors (GRP) in vitro.

Differences in the phenotypic and the functional properties of GRP using in vitro co-culture experiments with dorsal root ganglion (DRG) neurons. (A) Comparison of early and late passage GRP. Both early and late passage GRP were characterized by high expression of A2B5 and low expression of glial fibrillary acid protein (GFAP) typical of an immature state. Early and late passage GRP promoted comparable axon growth relative to control cultures consisting of DRG neurons alone. (B) GRP treated with inflammatory factors and their ability to support axon growth. GRP were exposed to various concentrations of Lipopolysaccharide (LPS)/Interferon gamma (IFNγ) for 24 hours and tested in co-culture experiments. GRP treated with low concentrations of LPS/IFNγ retained their axon growth supportive properties. In contrast, GRP treated with high concentrations of LPS/IFNγ showed a transient GFAP expression that was followed by a loss of A2B5 expression, and displayed an attenuation of their axon growth supporting properties.