Fig. 3

PSCs express RA pathway proteins. RA biosynthesis protein Raldh1 (red) is not expressed by Col1a1+ PSCs at P0 (green, open-arrows in A) but is expressed by some cells in the meninges (carets in A) and some neurons in the brain (arrows in A). At P21, Raldh1 (red, B) is expressed by Col1a1+ PSCs (green, B) surrounding blood vessels (arrows in B). In the stroke lesion, Raldh1 (red, C) is expressed in CoupTF2+ PSCs (green, arrows in C) and IB4+ macrophages (magenta, carets in C). Raldh2 (red, D, E) is expressed by Col1a1+ meningeal cells (green; carets in D, E), is only very weakly expressed by Col1a1+ PSCs surrounding IB4+ vessels at P0 (open-arrows, D), but Raldh2 signal is strong in Col1a1+ PSCs at P21 (arrows in E). Following stroke, Raldh2 (red, F) is expressed by CoupTF2+ PSCs (green, arrows in F). Some CoupTF2+ PSCs in the lesion do not express Raldh1 or Raldh2 (open-arrows in C, F). CRABP1 (red, G) is not expressed by Col1a1+ (green, G) meninges or PSCs at P0 (carets and open-arrows, respectively in G) though is expressed by Col1a1+ PSCs (green, H) surrounding IB4+ vessels at P21 (arrows in H). PDGFrα+ PSCs (red, I) in the stroke lesion express CRABP1 (green, arrows in I) though there are other CRABP1-expressing cells in the lesion (caret in I). CRABP2 (green, J, K) is expressed by PDGFrα meninges (red, carets in J, K) but not by PDGFrα+ PSCs (red open-arrows in J, K) at P0 or P21. CRABP2 (green, L) is expressed by some PDGFrα+ PSCs (red, arrows in L) in the stroke lesion. Open-arrows in L indicate PDGFrα+/CRABP2-negative cells. IB4 labels blood vessels and microglia/macrophages in A, C, D, G, H, J and L; DAPI (blue) marks nuclei in B, C, E, F, I, and K. Scale bars 100 μm