Local hepcidin increased intracellular iron overload via the degradation of ferroportin in the kidney

Hepcidin is a key regulator of iron homeostasis. Some studies showed that exogenous hepcidin decreased the expression of divalent metal transporter (DMT1) rather than ferroportin(FPN1) to regulate renal iron metabolism. This study explored the effects of hepcidin synthesized by the kidney and its mechanism of iron regulation. In the in vivo experiments, mice were divided into a unilateral ureter obstruction (UUO) model group and a sham operation group, and mice in the UUO model group were sacrificed on days 1, 3, 5 and 7. The expression of renal hepcidin, FPN1, DMT1 and the retention of renal iron were studied. In the in vitro experiments, we overexpressed hepcidin in HK-2 cells. Then we tested the expression of renal hepcidin, FPN1, DMT1 and observed the production of intracellular ferrous ions. Renal hepcidin expression was consistently higher in the UUO group than in the sham group from the first day. The expression of FPN1 gradually decreased, and the expression of DMT1 gradually increased in the UUO model. Intracellular ferrous ions significantly increased on the first day of the UUO model. In hepcidin overexpressed HK-2 cells, the expression of FPN1 was decreased, while the expression of DMT1 has no significant change. In addition, production of intracellular ferrous ions increased. Conclusion: local hepcidin can regulate iron metabolism in the kidney by adjusting the expression of FPN1. •First, build up kidney cell-specific (HK-2 cell) hepcidin-overexpressed model.•Second, local hepcidin regulates iron metabolism in the kidney by adjusting the expression of FPN1, whereas exogenous hepcidin reduces the expression of DMT1.•Third, co-fluorescence staining of hepcidin and ferrous ions showed renal iron accumulation closely related to local hepcidin.