STAT3-mediated astrocyte differentiation from mouse fetal neuroepithelial cells by mouse oncostatin M.

The interleukin (IL)-6 family of cytokines share gp130 as a signal-transducing receptor component. We here show that oncostatin M (OSM), a member of this family, and its receptor components were expressed in embryonic mouse brain and that OSM induced astrocytes in cultured fetal mouse neuroepithelial cells. OSM induced promoter activation of the gene for an astrocyte marker, glial fibrillary acidic protein. The activation was completely blocked by expression of a dominant negative form of STAT3, a transcription factor activated downstream of gp130, or by introduction of a mutation in the STAT3 binding motif in the promoter. Taken together with its expression, we suggest that OSM contributes to the induction of astrocyte differentiation in a fetal developing brain via STAT3 activation.