Co-culturing improves the OGD-injured neuron repairing and NSCs differentiation via Notch pathway activation

Neural stem cell (NSC) transplantation for ischemic stroke is expected to repair the neuronal injury and replace the lost neurons through cell-cell cross talk between injured neurons and the transplanted NSCs. Here, we set up an in vitro co-culturing system of oxygen-glucose deprivation (OGD) injured neurons and NSCs to investigate the neuronal repairing effect and effects on NSCs differentiation. We focused on the Notch1 pathway as a possible mediator of these effects. OGD-injured neurons induced increased activation of Notch1 in co-cultured NSCs, through the up-regulations of the DLL1, the Notch1 intracellular domain (NICD) and the down-stream genes Hes1/5. When the NSCs were pre-treated with the Notch pathway inhibitor DAPT, the activation of Notch1 was blocked, lower NSCs differentiation was detected and the neurotrophic effect was also abolished. As shown by the novel co-culturing system, the NSCs co-cultured with OGD injured neurons were induced to differentiate through the Notch1 pathway activation; and these induced NSCs showed greater potential to support both the repair of injured neurons and form new neurons.