One Step Closer to Remyelination after Perinatal Brain Damage: Wharton’s Jelly Mesenchymal Stem Cell-Derived Exosomes Drive Neural Progenitors towards Oligodendroglial Cell Fate

INTRODUCTION: The loss of oligodendrocyte progenitor cells leading to overall hypomyelination of the brain is a major hallmark in perinatal brain damage. Experimental transplantations of mesenchymal stem cells (MSC) in animal models of perinatal brain damage strongly indicate that the regenerative effects rely on released factors such as MSC-derived exosomes. METHODS: Thus, the aim of this study is to investigate the capacity of exosomes from human Wharton’s jelly-derived MSC (WJ-MSC) to determine neural progenitor cells (NPC) towards oligodendroglial cell fate. WJ-MSC-derived exosomes were isolated from culture supernatants by serial high-speed and ultracentrifugations. Exosome microRNA (miRNA) content was assessed by real-time PCR. After 72 h of co-culture with WJ-MSC-derived EV, NPC were evaluated for the expression of markers involved in oligodendroglial specification and differentiation by real-time PCR. RESULTS: miRNA that are involved in oligodendroglial cell fate specification and differentiation (miR-338, miR-9, miR-19b, miR-138) were present in WJ-MSC-derived exosomes. The expression of miR-338-3p, known to trigger oligodendrocyte specification, was significantly increased in NPC after co-culture with exosomes. In addition, the gene expression of the transcription factor neurogenic differentiation factor 1 (Neurod1), which blocks oligodendrogenic specification and is repressed by miR-338, was significantly reduced in NPC after co-culture with exosomes. Furthermore, the gene expression of the transcription factor Hairy and enhancer of split (HES1) induced by the Notch signaling pathway, which is activated during oligodendroglial specification, was significantly elevated in NPC after incubation with exosomes. CONCLUSION: In conclusion, isolated WJ-MSC-derived exosomes expressed miRNA having key roles in oligodendrogenesis. Exosomes induced NPC towards oligodendroglial cell fate, ascribing a promising role in neuroregeneration to WJ-MSC-derived exosomes. Financial support by Gottfried and Julia Bangerter-Rhyner Foundatio