GABA is an inducer of ?-to-?-like cell conversion in vivo. This conversion induces ? cell replacement mechanisms through the mobilization of duct-lining precursor cells that adopt an ? cell identity prior to being converted into ?-like cells, solely upon sustained GABA exposure. Importantly, these neo-generated ?-like cells are functional and can repeatedly reverse chemically induced diabetes in vivo. Similarly, the treatment of transplanted human islets with GABA results in a loss of ? cells and a concomitant increase in ?-like cell counts, suggestive of ?-to-?-like cell conversion processes also in humans. (Cell. 2017 Jan 12;168(1-2):73-85.e11)