Fig. 6.

Effect of RPE cells on neurite orientation in photoreceptors. Phase (A–C) and fluorescence (D,E) photomicrographs of neuronalenriched cultures (A) or cocultures (B–E) of ARPE-19 cells seeded on top of neuronal cultures, showing RPE lamellipodia edges (dashed lines) and the orientation of outgrowing axons (thin arrows). Photo-receptors (open arrows) were identified by their morphology or with the Rho4D2 monoclonal antibody (white thin arrows in D). In neuronal-enriched cultures, neurites grew randomly oriented (A), but in cocultures, neurite growth adopted a radial distribution pointing away from (B,D,E) or parallel to RPE cells (C). Rho4D2 staining of cocultures (D) and phalloidin staining (E) observed under confocal microscopy confirmed that most photoreceptors ended on top of RPE cells with their axons pointing away from these cells. Scale bars = 10 µm.