Activin A promotes human embryonic stemcells to directly differentiate into retinal pigment epithelium cells

Retinal pigment epithelium (RPE) is a kind of monolayer cells situated between neural retina and choroid, and plays an important role in maintaining the functions of retina and photoreceptor. Its functions mainly include absorbing stray light, providing nutrients for neural retina and phagocytizing outer section of photoreceptor. Photoreceptor damage caused by dysfunctions, degeneration and loss of RPE is the main reason that leads to age-related macular degeneration (AMD) and retinitis pigmentosa (RP).