Migrating the adult brain: Vascular and ECM mediated?

Abstract

New cells are continuously added to the rodent olfactory bulb (OB) throughout development and in adult. These cells migrate tangentially from the sub‐ventricular zone along the rostral migratory stream to the OB where they migrate radial from the centre to periphery of the OB. In adult, this tangential migration takes place in ‘chains’ of cells contained within glial tubes, in contrast, radial migratory cells lack these defined glial tubes and chains, migrating instead as individual cells. Although different modalities of radial migration have been described in other brain regions, the mechanisms governing radial migration in the OB are still largely unknown. Here we identify a modality of migration in which neuronal precursors migrate along blood vessels toward their destination. Our results show that many radially migrating cells associate with the vasculature in the granule cell layer of the OB and in vivo time lapse imaging demonstrates that they use blood vessels as scaffold for their migration through an interaction with the extracellular matrix and perivascular astrocytes end feet. Indeed, matrix remodeling appears important for normal migration in this pathway.