Olfactory mucosa-derived mesenchymal stem cells differentiate towards a Schwann cell-like phenotype for peripheral nerve regeneration

Peripheral nerve injury remains a poorly addressed malady. Synthetic solutions have failed to gain traction in the clinic for their poor outcomes, especially with larger gaps or tissue loss. A key shortcoming of these off-the-shelf options is the lack of supportive Schwann Cells (SCs). Due to harmful donor site morbidity as a requirement for autologous SC harvesting, alternatives are required. Mesenchymal stem cells (MSCs) are a promising source of stem cells for treating peripheral nerve injuries. Here, we present, to our knowledge, the first investigation of scaffold-free, defined-media differentiation of olfactory mucosa-derived MSC (OM-MSC) towards a Schwann cell (SC)-like phenotype. OM-MSCs are a promising source of SCs, as isolation can be accomplished with a minimally invasive procedure compared to autologous nerve harvest and isolation. OM-MSC differentiation was accomplished with SC conditioned media (SCCM) or a defined growth factor supplemented media (GF). The differentiation process and resulting populations were characterized by immunocytochemistry, RT-qPCR, and RNA seq. Functionality of differentiated populations was assessed in an in vitro co-culture model to evaluate interaction with sensory neurons (dorsal root ganglia) juxtaposed to native SCs. Compared to undifferentiated MSCs, differentiation protocols resulted in significant changes in morphology, gene expression, and functionality using SCCM and GF, representing key characteristics of SCs. Specifically, differentiated populations exhibit elongated, spindle-like morphologies, a high degree of eccentricity, increased S100β, CD44, and NGF expression, and colocalization of myelin basic proteins with neurites in the co-culture model. In conclusion, this work highlights the potential of OM-MSCs to be expanded and differentiated to SCs to improve synthetic scaffolds or for use in decellularized allografts for nerve repair.