Immunoreactivities for hepcidin, ferroportin, and hephaestin in astrocytes and choroid plexus epithelium of human brains

Iron plays essential roles in the central nervous system. However, how the iron level is regulated in brain cells including glia and neurons remains to be fully clarified. In this study, the localizations of hepcidin, ferroportin, and hephaestin, which are known to be involved in iron efflux, were immunohistochemically examined in autopsied human brains. Immunoreactivities for hepcidin and ferroportin were observed in granular structures within the cytoplasm of reactive astrocytes and epithelial cells of the choroid plexus. Granular structures showing immunoreactivities for hepcidin and ferroportin were also stained with antibodies for early endosome antigen 1 (EEA1). In addition, immunoreactivity for hephaestin was observed in the cytoplasm of epithelial cells of the choroid plexus as well as reactive astrocytes. Immunoreactivity for hephaestin in the cytoplasm of reactive astrocytes was occasionally colocalized with immunoreactivity for EEA1, while that of hephaestin was frequently observed in the cytoplasm showing no immunoreactivity for EEA1. These findings suggest that immunoreactivities for hepcidin and ferroportin are localized in close proximity to granular structures showing immunoreactivity for EEA1 in the cytoplasm of human brain astrocytes. They also suggest that immunoreactivity of hephaestin is localized in the cytoplasm of the choroid plexus epithelium as well as reactive astrocytes of human brains.