Figure 5. Neuronal markers are expressed in retinal pigment epithelium cells in culture but are lost after culture on a porcine lens capsule membrane (PLC). The expression of neurofilament heavy and medium polypeptides (NF-H and NF-M respectively) varied in dimethyl sulfoxide (DMSO)-treated cells. A: The first two panels show the variation of NF-H expression within the same dish of DMSO-treated ARPE-19 cells, which is increased across the whole dish after fenretinide (FR) treatment. Similarly, the expression of NF-M varies within cells of the same field and is increased by fenretinide. B: Passage 2 primary human RPE cells and an additional human RPE cell line (h1RPE7) express the neuronal markers NF-H and synaptophysin (SYP). C: Culturing ARPE-19 on a PLC decreases the expression of neuronal markers in control cells and prevents the fenretinide-induced increase of neuronal markers. Protein staining is indicated by the color of the text (red or green). All scale bars equal 50 μm.