More specifically, we discovered that Pdx1 prevents mesenchymal reprogramming of β-cells by maintaining the expression of Ovol2, an epithelial-specific repressor of Zeb2. Together, our findings indicate that miR-7-mediated β-cell dedifferentiation triggers EMT signalling and a process reminiscent of a response to tissue injury predisposing to islet fibrosis in diabetes. The gene discussed is PDX1; the disease is diabetes mellitus.