FGF4 and diabetes mellitus: To further elucidate the role played by AMPK-FOXO1 in mediating the therapeutic effects of FGF4 on DKD, we established a mouse model with podocyte-specific knockout of Ampka1/a2 (Ampk-PKO) and subjected these mice to STZ-induced diabetes, followed by treatment with rFGF4 or vehicle control (Fig. 6a, b and Supplementary Fig. 11a).