A cell-permeable, diarylurea analog that can reversibly induce cell proliferation of primary retinal pigment epithelial (RPE) cells from rodents and from fetal and adult human donors (~25nM). Its action suggested to be mediated through Erb3 binding protein 1 (Ebp1). Non-proliferating RPE cells at passage 6 appear to respond well to WS3 treatment, whereas actively proliferating cells in passage 1 to 4 do not exhibit any increase in proliferation. These cells can differentiate into functional monolayer following WS3 withdrawal. However, WS3-expanded adult human RPE cells differentiate less effectively when compared to stem cell-derived RPE cells. The expanded RPE cells are shown to preserve vision when transplanted into rodent models of retinal degeneration. Also shown to induce proliferation of mouse R7T1 beta cells (EC50 = 74nM). Not reported to induce any genetic changes or tumorigenic events.
