1 Institute of Diabetes and Regeneration Research, Helmholtz Diabetes Center, Helmholtz Zentrum München, Munich, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, Munich, Germany; German Center for Diabetes Research (DZD), Munich, Germany.
2 Institute of Diabetes and Regeneration Research, Helmholtz Diabetes Center, Helmholtz Zentrum München, Munich, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, Munich, Germany; German Center for Diabetes Research (DZD), Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany. Electronic address: heiko.lickert@helmholtz-muenchen.de.