Figure 4.

The effect of Shh signaling on proliferation and differentiation of Olig2⁺ cells in vitro. (A) In mixed cell cultures at midgestation, Olig2⁺ cells (red) were co-labeled with Ki67 (cell proliferation marker), MAP2 (neuronal marker), vimentin (RGC marker), PDGFRα(early OPC marker) and O4 (late OPC marker) in green. Nuclear staining with bisbenzimide (BB) in blue. Scale bar: 20 μm. (B) Proliferation of Olig2⁺ cells, estimated by double-labeling with Ki67, increased after Shh treatment, but did not change after either cyclopamine or combined cyclopamine and Shh treatments. (C) The composition of Olig2⁺ cell population in 17 gw cortical mixed cell cultures changed with manipulation of Shh signaling. Graph shows the percentage of Olig2⁺ neurons (Olig2⁺/MAP2⁺), RGCs (Olig2⁺/Vimentin⁺) or early (Olig2⁺/PDGFRα⁺) and late (Olig2⁺/O4⁺) OPCs out of the total number of Olig2⁺ cells; note the selective increase of Olig2/PDGFRα⁺ cells and the proportional decrease of Olig2/vimentin⁺ cells after Shh treatment. Data are presented as mean ± s.e.m. ^*p < 0.05, ^**p < 0.01 vs. control.