Suppression of STAT3 signaling promotes cellular reprogramming into insulin-producing cells induced by defined transcription factors

BACKGROUND: STAT3 has been demonstrated to play a role in maintaining cellular identities in the pancreas, whereas an activating STAT3 mutation has been linked to impaired β-cell function. METHODS: The role of STAT3 in β-cell neogenesis, induced by the exogenous expression of Pdx1, Neurog3, and Mafa, was analyzed in vitro and in vivo. FINDINGS: The expression of phosphorylated STAT3 (pSTAT3) was induced in both Pdx1-expressing and Mafa-expressing cells, but most of the induced β cells were negative for pSTAT3. The suppression of STAT3 signaling, together with exogenously expressed Pdx1, Neurog3, and Mafa, significantly increased the number of reprogrammed β cells in vitro and in vivo, enhanced the formation of islet-like clusters in mice, and ameliorated hyperglycemia in diabetic mice. INTERPRETATION: These findings suggest that STAT3 inhibition promotes cellular reprogramming into β-like cells, orchestrated by defined transcription factors, which may lead to the establishment of cell therapies for curing diabetes. FUND: JSPS, MEXT, Takeda Science Foundation, Suzuken Memorial Foundation, Astellas Foundation for Research on Metabolic Disorders, Novo Nordisk, Eli Lilly, MSD, Life Scan, Novartis, and Takeda.