Fig. 9

tPA induces chemokinesis on OLs via its EGF-like domain. a Photomicrographs from WT mice tissue sections show representative images of tPA (red), EGFR (green) and Olig2 (blue) immunoreactivities in the ventral ventricular zone of mice spinal cords at E13, E15, E17, P0, P3 and P7. Dotted lines show ependymal canal limits. (Representative images, n = 3 per group). b Photomicrographs from WT mice tissue sections show representative images of EGFR (green) and Olig2 (blue) immunoreactivities in the pMN domain of mice spinal cords at E13. The inlet shows 3D reconstruction from confocal acquisition. (Representative images, n = 3 per group). c Photomicrographs from WT mice tissue sections show representative images of tPA (red), EGFR (green) and Olig2 (blue) immunoreactivities in the contralateral (left column) and ipsilateral (right column) corpus callosum of adult mice, 3, 7, 14 and 21 days after lysolecithin injection. Full lines show lateral ventricle limits and dotted lines show corpus callosum limits. (Representative images, n = 3 per group). d Photomicrographs from adult WT mice tissue sections show representative images of EGFR (green) and Olig2 (blue) immunoreactivities in the lesion 3 days after injection. (Representative images, n = 3 per group). e Rat OPCs were cultured for 24 h. Photomicrographs show representative fields after Olig2 (red) and EGFR (green) immunostaining or the merged images (yellow). (representative images, n = 3 per group). f Rat primary cultures of OPCs were seeded on the upper compartment of Boyden chambers and treated in indicated conditions for 24 h. g Proteins from cultured OPCs treated with tPA (10μg/ml) or corresponding vehicle for indicated times were subjected to western blot for the phosphorylated (P-Erk) or total (Total Erk) forms of Erk. Chemokinesis was estimated by counting cells in the lower compartment in control conditions or in the presence of 0.2 μg/mL FGF2, 10 μg/mL tPA, 10 μg/mL tPA + 5 μM inhibitor of the kinase activity of EGFR (AG1478), 5 μM AG1478, 10 μg/mL tPA complexed with the proteolytic inhibitory peptide GGACK. (mean ± SEM; n = 9, three independent cultures; *p < 0.05, Mann–Whitney U test). cc: corpus callosum; dpi: days post injection; E: embryonic day; LV: lateral ventricle; OPC: oligodendrocyte precursor cell; P: postnatal day. Scale bars: 20 μm