PEDF

Pigment epithelium-derived factor (PEDF) also known as serpin F1 (SERPINF1), is a multifunctional secreted protein that has anti-angiogenic, anti-tumorigenic, and neurotrophic functions. Found in vertebrates, this 50 kDa protein is being researched as a therapeutic candidate for treatment of such conditions as choroidal neovascularization, heart disease, and cancer. In humans, pigment epithelium-derived factor is encoded by the SERPINF1 gene.

Discovery

Pigment epithelium-derived factor (PEDF) was originally discovered by Joyce Tombran-Tink and Lincoln Johnson in the late 1980s. This group was studying human retinal cell development by identifying secreted factors produced by the retinal pigmented epithelium (RPE), a layer of cells that supports the retina. Upon noticing RPE produced a factor that promoted the differentiation of primitive retinal cells into cells of a neuronal phenotype, they set out to determine the identity of the factor. They isolated proteins unique to RPE cells and tested the individual proteins for neurotrophic function, meaning promoting a neuronal phenotype. A neurotrophic protein around 50 kilodaltons (kDa) was identified and temporarily named RPE-54 before being officially termed pigment epithelium-derived factor.