A method of increasing insulin content in a pancreatic beta cell is disclosed. The method comprising expressing in the pancreatic beta cell an exogenous polynucleotide encoding at least one microRNA or a precursor thereof, wherein the microRNA is selected from the group consisting of miR-15, miR-16, miR-24, miR-26, miR-27, miR-29, miR-30, miR-129, miR-141, miR-148, miR-182, miR-200, miR-376 and Let-7, thereby increasing the insulin content in the pancreatic beta cell.