The Inactivation of Arx in Pancreatic alpha-Cells Triggers Their Neogenesis and Conversion into Functional beta-Like Cells

Recently, it was demonstrated that pancreatic new-born glucagon-producing cells can regenerate and convert into insulinproducing beta-like cells through the ectopic expression of a single gene, Pax4. Here, combining conditional loss-of-function and lineage tracing approaches, we show that the selective inhibition of the Arx gene in alpha-cells is sufficient to promote the conversion of adult alpha-cells into beta-like cells at any age. Interestingly, this conversion induces the continuous mobilization of duct-lining precursor cells to adopt an endocrine cell fate, the glucagon(+) cells thereby generated being subsequently converted into beta-like cells upon Arx inhibition. Of interest, through the generation and analysis of Arx and Pax4 conditional double-mutants, we provide evidence that Pax4 is dispensable for these regeneration processes, indicating that Arx represents the main trigger of alpha-cell-mediated beta-like cell neogenesis. Importantly, the loss of Arx in alpha-cells is sufficient to regenerate a functional beta-cell mass and thereby reverse diabetes following toxin-induced beta-cell depletion. Our data therefore suggest that strategies aiming at inhibiting the expression of Arx, or its molecular targets/co-factors, may pave new avenues for the treatment of diabetes.