In vivo magnetic resonance imaging of ferritin-based reporter visualizes native neuroblast migration.

Adult neurogenesis research in mammals presents a challenge as most stem cells and progenitors are located deep in opaque brain tissues. Here, we describe an efficient ferritin-based magnetic resonance imaging (MRI) reporter and its use to label mouse subventricular zone progenitors, enabling in vivo visualization of endogenous neuroblast migration toward the olfactory bulb. We quantify the effect of the ferritin transgene expression on cellular iron transport proteins such as transferrin receptor, divalent metal transporter and STEAP reductase. Based on these data, we elucidate key aspects of the cellular pathways that the reporter utilizes to load iron and form its superparamagnetic core. This MRI reporter gene platform can facilitate the non-invasive study of native or transplanted stem cell migration and associated neurogenic or therapeutic molecular events in live animals.