Objective: To investigate the effects of blocking VEGF expression on the retinal pigment epithelium (RPE) in vitro.
Methods: RPE was transfected with plasmid encoding anti-sense of VEGF by lipofectin. RPE clones with stable expression of anti-sense of VEGF were screened by neomycin (G418). The changes of RPE and the level of VEGF secreted by RPE were observed by immunofluorescence immunohistochemical staining, Elisa and inverted-microscope.
Results: Transdifferentiation of cultured adult human retinal pigment epithelium cells to neurons was induced by blocking VEGF expression. The transdifferentiation was a direct phenotypic change from RPE cell to neurons without cell differentiation. The transdifferentiated neurons showed up-regulated expression of VEGF receptor 2 (Flk-1) and expressed several markers of retinal ganglion cell, including Thy1.1 and neurofilament.
Conclusion: Blocking of VEGF expression and up-regulation of Flk-1 can induce transdifferetiation of adult human retinal pigment epithelium cells into ganglion cells.