Intracerebral expression of transferrin receptors in iron-deficient rats

In iron-deprived animals, transferrin receptors were increasingly expressed in both capillary endothelium and choroid plexus epithelium. Transferrin receptors were also increasingly expressed in neurons. It is very likely that this principal distribution is also seen in other mammals, including man. Prospective physiological studies on iron-homeostasis should account for the ability of neurons to internalize iron-transferrin complexes by receptor-mediated endocytosis. The results are important in the context of current therapies for treatment of brain tumors using conjugation of chemotherapeutics to transferrin or transferrin receptor antibodies, as toxin-conjugated transferrin may have the potential of harming normal neurons expressing the transferrin receptor. Moreover, the fact that neurons hallmark transferrin receptors may open new vistas on the role of an impaired intracerebral iron-homeostasis for formation of neurodegenerative disorders.