TMOD-30. DISRUPTION OF NORMAL RADIAL GLIA DEVELOPMENT IN AN NF2-ALTERED NEUROEPITHELIAL STEM CELL MODEL

Abstract NF2-related schwannomatosis is a tumor predisposition syndrome caused by mutations in the NF2 gene and associated with spinal ependymomas (SP-EPN). SP-EPNs are suspected to originate from aberrations in the radial glia (RG) cell lineage. These tumors are only effectively treated through high-risk surgical resection, emphasizing the critical need for identification of targets for medical therapy. Yet, the role of NF2-dependent disruption in RG cell development is poorly understood. We hypothesize that this mutation may be halting normal RG cell differentiation, resulting in a RG-like stem cell that is driving SP-EPN formation. An NF2-knockout was generated in neuroepithelial stem (NES) cells using CRISPR/Cas9. Knockouts were validated using Western blot and Sanger sequencing. In vitro differentiation was induced with removal of growth factors. NF2-knockout phenotypes were assessed with real-time polymerase chain reaction and compared with wildtype NES cells. Preliminary data has shown that NF2-knockout cells express similar levels of early pan-neural and neural stem cell genes compared to wildtype after CRISPR editing. The NF2-knockout cells retain this stem cell-like gene expression following attempted differentiation, whereas wildtype cells take on a primarily neural phenotype. The knockout cells also form what appears to be pre-neoplastic spheres when allowed to differentiate. NF2-knockout NES cells fail to differentiate normally compared to wildtype NES cells. They retain early RG-like markers, including SOX2, BLBP, and GFAP. Furthermore, formation of spheres when growth factors were removed hints at NF2 loss being relevant to formation of pre-neoplastic growths. Future work will include investigating downstream effects of NF2 loss in this model.