Biological Activity:
WS3 is a highly potent and selective small molecule that promotes pancreatic β cell and RPE cells expansion, identified by a high-throughput, cell-based screening. It can induce proliferation of mouse R7T1 β cells with an EC₅₀ ~0.074 µM, and expansion of primary rat and human β cells in dissociated and intact islet format with similar EC_50. WS3 can also reversibly proliferate primary RPE cells isolated from fetal and ***** human donors. Following withdrawal of WS3, RPE cells differentiate into a functional monolayer, as exhibited by their expression of mature RPE genes and phagocytosis of photoreceptor outer segments. Furthermore, chemically expanded RPE cells preserve vision when transplanted into dystrophic Royal College of Surgeons (RCS) rats, a well-established model of retinal degeneration.