Hepcidin overexpression in astrocytes alters brain iron metabolism and protects against amyloid-β induced brain damage in mice

Progressive iron accumulation in the brain and iron-induced oxidative stress are considered to be one of the initial causes of Alzheimer's disease (AD), and modulation of brain iron level shows promise for its treatment. Hepcidin expressed by astrocytes has been speculated to regulate iron transport across the blood-brain barrier (BBB) and control the whole brain iron load. Whether increasing the expression of astrocyte hepcidin can reduce brain iron level and relieve AD symptoms has yet to be studied. Here, we overexpressed hepcidin in astrocytes of the mouse brain and challenged the mice with amyloid-beta(25-35) (A beta(25-35)) by intracerebroventricular injection. Our results revealed that hepcidin overexpression in astrocytes significantly ameliorated A beta(25-35)-induced cell damage in both the cerebral cortex and hippocampus. This protective role was also attested by behavioral tests of the mice. Our data further demonstrated that astrocyte-overexpressed hepcidin could decrease brain iron level, possibly by acting on ferroportin 1 (FPN1) on the brain microvascular endothelial cells (BMVECs), which in turn reduced A beta(25-35)-induced oxidative stress and apoptosis, and ultimately protected cells from damage. This study provided in vivo evidences of the important role of astrocyte hepcidin in the regulation of brain iron metabolism and protection against A beta-induced cortical and hippocampal damages and implied its potential in the treatment of oxidative stress-related brain disorders.