The Recently Identified P2Y-Like Receptor GPR17 Is a Sensor of Brain Damage and a New Target for Brain Repair
Figure 3
GPR17 expression in the mouse germinative zones.
Micrographs depicting GPR17 staining in coronal sections of the intact anterior forebrain. (A) In the walls of the lateral ventricles (LV), GPR17 (red fluorescence) is highly expressed in ependymal cells, which are in direct contact with ventricle cavities and also express the S100β protein (green fluorescence). Cells co-expressing both GPR17 and S100β in this cell layer are indicated in yellow. (B, C) Specific GPR17 staining (red fluorescence) is also found in the subependymal layer of LV. (B): several of these cells show a morphology that is reminiscent of the GPR17+ oligodendrocyte precursors found in brain parenchyma (see also Figure 2 and panel D). These GPR17+ cells do not co-stain for the astrocytic marker GFAP (green fluorescence in B), that is also specifically expressed by multipotent adult stem cells. (C) As expected, in the subependymal layer of lateral ventricles, several double-cortin (DCX)+ neuronal precursors are evident (red fluorescence); however, these cells do not co-express GPR17 (here shown in green fluorescence). (D) An additional image of GPR17+ ramified precursors (red fluorescence) in LV subependymal layer (arrows) and in c. striatum (CST) of brain parenchyma (Hoechst 33258 staining of cell nuclei is also shown in blue). GPR17+ cells in the subependymal layer were often found to protrude their processes in the ventricular cavity. (E) Double fluorescence image showing expression of GPR17 (red fluorescence) in ramified cells in the hippocampus (DG: dentate gyrus). Also in this brain area, GPR17 immunoreactivity does not co-localize with GFAP (green fluorescence). Scale bars: A–C 50 µm; D 10 µm; E 100 µm.