Introduction: Spinal cord injury currently has no clinical treatment. One promising therapy is the transplantation of oligodendrocyte progenitor cells (OPCs) which can potentially remyelinate axons. Our hypothesis is that OPCs can be generated from mouse fibroblasts using an induced pluripotent stem (iPS) cell intermediary.
Methods: Fibroblasts were cultured from mice expressing transmembrane eGFP. IPS cells were generated using the Yamanaka method. These cells were subsequently cultured into neural stem cells and then expanded as OPCs, according to modified protocols established for generating OPCs from embryonic stem cells. Immunofluorescent staining for Olig2 and other OPC markers was utilized to confirm their identity, and presence of those markers was corroborated by RT-PCR. Subsequently, the OPCs were transplanted into brains of a demyelinated mouse model to demonstrate functionality. The mice were sacrificed 6 weeks after injection, brain sections were stained for MBP, NF200, and then examined under fluorescence microscopy.
Results: Immunofluorescent staining for Olig2 demonstrated successful generation of OPCs from eGFP mouse fibroblasts. RT-PCR confirmed expression of Olig2. Up to 90% of generated cells expressed OPC markers. Survival of transplanted cells in demyelinated mouse brain was seen, as was production of myelin.
Conclusions: Generation of OPCs from mouse fibroblasts can be successfully accomplished using an iPS cell intermediary. Future studies will examine their effects after transplantation into a spinal cord injury model.
Patient Care: The next step of our project will apply the OPCs generated to spinal cord injury models in rodents. That will potentially confirm the benefit of this method, and thus open the door to clinical trials utilizing OPCs. Protocols for derivation of OPCs from human iPS cells already exist. Apart from the Yamanaka method, which utilizes retroviral vectors to generate iPS cells, new approaches are on the horizon that have the potential for safer application in humans (non-integrating vectors). This could potentially grow into a viable treatment option for spinal cord injury.
Learning Objectives: Following this presentation the audience should be able to recognize the potential for oligodendrocyte progenitor transplantation in spinal cord injury, and the possibility of generating those cells from induced pluripotent stem cells.