IFNγ-stimulated dendritic cell extracellular vesicles can be nasally administered to the brain and enter oligodendrocytes

Extracellular vesicles secreted from IFN gamma-stimulated rat dendritic cells (referred to here as IFN gamma-DC-EVs) contain miRNAs which promote myelination (including but not limited to miR-219), and preferentially enter oligodendrocytes in brain slice cultures. IFN gamma-DC-EVs also increase myelination when nasally administered to naive rats. While we can infer that these extracellular vesicles enter the CNS from functional studies, here we demonstrate biodistribution throughout the brain after nasal delivery by way of imaging studies. After nasal administration, Xenolight DiR-labelled IFN gamma-DC-EVs were detected 30 minutes later throughout the brain and the cervical spinal cord. We next examined cellular uptake of IFN gamma-DC-EVs by transfecting IFN gamma-DC-EVs with mCherry mRNA prior to nasal administration. mCherry-positive cells were found along the rostrocaudal axis of the brain to the brainstem. These cells morphologically resembled oligodendrocytes, and indeed cell-specific co-staining for neurons, astrocytes, microglia and oligodendrocytes showed that mcherry positive cells were predominantly oligodendrocytes. This is in keeping with our prior in vitro results showing that IFN gamma-DC-EVs are preferentially taken up by oligodendrocytes, and to a lesser extent, microglia. To confirm that IFN gamma-DC-EVs delivered cargo to oligodendrocytes, we quantified protein levels of miR-219 mRNA targets expressed in oligodendrocyte lineage cells, and found significantly reduced expression. Finally, we compared intranasal versus intravenous delivery of Xenolight DiR-labelled IFN gamma-DC-EVs. Though labelled IFN gamma-DC-EVs entered the CNS via both routes, we found that nasal delivery more specifically targeted the CNS with less accumulation in the liver. Taken together, these data show that intranasal administration is an effective route for delivery of IFN gamma-DC-EVs to the CNS, and provides additional support for their development as an EV-based neurotherapeutic that, for the first time, targets oligodendrocytes.

Automated summary

IFN gamma-DC-EVs, secreted from dendritic cells and containing miRNAs promoting myelination, show enhanced uptake by oligodendrocytes when delivered nasally in rats. Imaging studies revealed widespread distribution throughout the brain and cervical spinal cord post-nasal administration. The preferential targeting of the CNS and reduced accumulation in the liver indicate that intranasal delivery is an effective route for EV-based neurotherapeutics targeting oligodendrocytes.