Differentiation of neural stem cells influences their chemotactic responses to vascular endothelial growth factor

Although much effort has been devoted to the delineation of factors involved in the migration of neural stem/progenitor cells (NSCs), the relationship between the chemotactic response and the differentiation status of these cells remains elusive. In the present study, we found that NSCs in varying differentiation states possess different chemotactic responses to vascular endothelial growth factor (VEGF): first, the number of chemotaxing NSCs and the optimal concentrations of VEGF that induced the peak migration vary greatly; second, time-lapse video analysis shows that NSCs at certain differentiation states migrate more efficiently toward VEGF, although the migration speed remains unchanged irrespective of cell states; third, the phosphorylation status of Akt, ERK1/2, SAPK/JNK, and p38MAPK is closely related to the differentiation levels of NSCs subjected to VEGF; and, finally, although inhibition of ERK1/2 signaling significantly attenuates VEGF-stimulated transfilter migration of both undifferentiated and differentiating NSCs, NSCs show normal chemotactic response after treatment with inhibitors of SAPK/JNK or p38MAPK. Meanwhile, interference with PI3K/Akt signaling prevents only NSCs of 12 hr differentiation, but not NSCs of 1 day or 3 days differentiation, from migrating in response to VEGF. Moreover, blocking of PI3K/Akt or MAPK signaling impairs the migration efficiency and/or speed, the extent of which depends on the cell differentiation status. Collectively, these results demonstrate that differentiation of NSCs influences their chemotactic responses to VEGF: NSCs in varying differentiation states have different migratory capacities, thereby shedding light on optimization of the therapeutic potential of NSCs to be employed for neural regeneration after injury.