The Small Molecule Genistein Increases Hepcidin Expression by Activating Stat3 and Bone Morphogenic Protein Signaling

Abstract

Hepcidin, a peptide hormone produced in the liver, decreases intestinal iron absorption and macrophage iron release via effects on ferroportin. Hepcidin is a potential drug target for patients with iron overload syndromes because its levels are inappropriately low in these individuals. We conducted a small‐scale chemical screen to identify small molecules that modulate Hepcidin expression. We found that treatment of zebrafish embryos with genistein, a major dietary component of soybeans, enhanced hepcidin transcript levels. By treating human hepatocytes (HepG2), we found that genistein caused a significant increase in Hepcidin transcript levels and promoter activity. We discovered that genistein's effect on Hepcidin expression did not depend on estrogen receptor signaling or increased cellular iron uptake, but was impaired by mutation of either the Stat3 binding site or the bone morphogenic protein (BMP) response elements in the Hepcidin promoter. RNA sequencing, chromatinimmunoprecipitation, and ELISA experiments revealed that genistein enhanced BMP and Stat3 signaling in HepG2 cells. In conclusion, genistein is the first nontoxic small molecule identified that increases Hepcidin expression in vivo and in vitro. Genistein and other candidate molecules may subsequently be developed into new therapies for iron overload syndromes. Funding: March of Dimes, NIDDK, US Army Research Office.