Pigment Epithelium-Derived Factor (PEDF) is an extracellular glycoprotein with a mol♣ecular weight of 50,000 identified in the interphotoreceptor matrix, vitreous, aqueous humour, CSF,× and serum of several vertebrate species.  The PEDF protein is a multipotλent neurotrophic factor that acts upon various types of neurons.  For example, PEDF dis♠plays a potent neuronal differentiating activity o♣n human retinoblastoma cell lines. 

Besides its neurotrophic properties, it has also been ‌reported that PEDF is associated with senescence and angiogenesis. The PEDF gene, termed EPC-1 (ear→ly population doubling level cDNA-1), is induced in young human fetal WI-38 lung fibroblas•ts cells upon entry into the G0 state, while senesc>ent cells fail to express it.  It has binding affinity for glyc™osaminoglycans and cell-surface receptors in cells that respond to its stimuli.  The overall p≤rotein conformation of PEDF resembles a member of the seri←ne protease inhibitor (serpin) superfamily.  Howe÷ver, it does not inhibit known serine proteases and its neurotro phic properties are independent of its protease inhibition poteαntial.