Effect Of Glioma On The Migration Of Differentiating NSCs

The discovery of neural stem/progenitor cells (NSCs) and their capacity to regenerate neural cells in the adult central nervous system (CNS) have altered old dogmas in neurobiology and raised hopes for novel treatment of CNS diseases. Previous work has showed that NSCs have notable migratory abilities within the CNS under physiological and pathological conditions. Transplanted NSCs have the capacity for precise migration to even widespread and distant areas of pathology in experimental models of CNS disease. In vitro as well as in vivo studies demonstrate the migration tendency of NSCs towards glioblastoma, a malignant glioma that is currently incurable because of its highly invasive nature, and thus highlight the potential use of NSCs as delivery vehicles for therapeutic genes. However, the mechanisms and factors that regulate migration are not well understood. Here, we focus on the effect of glioma conditioned medium and injury-induced factors on the migration of differenting NSCs.In the present study, we purified NSCs from the subventricular zone (SVZ) of newborn rat brain and cultured in Neural Basal Meidium plus B27. These NSCs were characterized by morphology, antigen expression (nestin, GFAP and Tuj1) and differentiation potential. Results showed that these primary NSCs can maintain undifferentiated state and can differentiate into neurons, oligodendrocytes and astrocytes.Next, we set up a model of NSCs differentiation in vitro in H-DMEM supplement with 1% fetal calf serum (FCS). NSCs were treated with glioma conditioned medium or stromal cell-derived factor (SDF-1α). The migration capability of NSCs at different differentiation states were analyzed by time-lapse video analysis. Results showed that glioma conditioned medium didn't influenced the migration distance of NSCs while the persistence and the migration speed were significantly increased, upon differentiation for 0~48 h. In particular, differentiating NSCs treated with glioma conditioned medium displayed a more pronounced increase in the migration persistence compared with undifferentiated NSCs and untreated NSCs. SDF-1α, one of the essential constituents in glioma conditioned medium and an already known chemoattractant for NSCs, was also used to study the responsiveness of differentiating NSCs. Our results indicated that treatment with SDF-1αat 5 ng/ml didn't influence the persistence, the migration distance and speed during the differentiation period (0~48 h). Higher concentrations (20 ng/ml and 80 ng/ml), by contrast, led to a significant increase in the migration distance and persistence of NSCs in the early phase of differentiation (0-24 h), and a signifcant increase in the migration and efficiency persistence after 24 h.Finally, using a Boyden Chemtaxis Chamber and a neural stem cells line, C17.2, we further analyzed the migratory behavior of NSCs at different states of differentiation in response to SDF-1α. Consistent with our previous data, Boyden Chamber analysis showed that cells of 24-h differentiation displayed the strongest tropism toward SDF-1αcompared with undifferentiated C17.2 cells. After 24 h of differentiation, the migratory responsiveness decreased over time. On the 7th day, less C17.2 cells migrated to SDF-1αthan did normal cells that were at an undifferentiated state.In view of the above experimental results we believe that there are inseparable relationship between the differentiation state and the migration of NSCs. The different responsiveness of NSCs to glioma conditioned medium and to SDF-1αmight attribute to the orchestration of a variety of factors present in the glioma conditioned medium, which, besides SDF-1α, includes stem cell factor (SCF-1), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and other as yet unknown growth factors. Together, our study has not only successfully set up the culture platform and differentiation model of NSCs, but also found a key point in the course of glioma and injury-induced factors induced migration of differenting NSCs. This discovery contributes to better understanding of the migration and differentiation mechanisms of NSCs, and thus would be helpful in NSCs transplantation therapy for CNS diseases.