Hepcidin targets ferroportin for degradation in hepatocytes

Hepcidin, a circulating regulatory hormone peptide produced by hepatocytes, functions as the master regulator of cellular iron export by controlling the amount of ferroportin, an iron exporter present on the basolateral surface of intestinal enterocytes and macrophages. Hepcidin binding to ferroportin induces its internalization and degradation, resulting in cellular iron retention and decreased iron export. Whether hepatocytes express ferroportin that could be targeted by hepcidin has remained a subject of debate. Here, we describe a hepatocyte culture system expressing high levels of ferroportin, and demonstrate that both endogenously secreted and synthetic hepcidin are fully active in down-regulating membrane-associated ferroportin. In agreement with this result, ferroportin is stabilized in liver hepatocytes of hepcidin-deficient mice and accumulates in periportal areas, supporting the centrolobular iron deposition observed in these mice. In conclusion, we show that hepcidin can trigger ferroportin degradation in hepatocytes, which must be taken into account when considering hepcidin therapeutics.