Abstract
Increasing evidence suggests that mesenchymal stem cells(MSCs) have beneficial effects in hypoxic ischemic reperfusion injury, but the underlying mechanisms are unclear. Here, we first examined the effect of OGD reperfusion injury on the vulnerability of human NPs derived from human embryonic stem cells (hESCs) with regard to cell survival and oxidative stress. Cellular deregulation was assessed by measuring glutathione levels, basal calcium and intracellular calcium [Ca2+]i response under KCl stimulation, as well as the key parameters of proliferation, glial progenitor marker expression and migration. Next, the influence of WJ-MSCs in recovering these parameters was evaluated, and the role of Phosphatidyl-inositol-3-Kinase(PI3K) pathway in actuating the protective effect was assessed. OGD reperfusion injury induced significant increases in cell death, ROS generation, oxidative stress susceptibility and decreased glutathione levels in NPs, accompanied by rises in basal [Ca2+]i, KCl-induced [Ca2+]i, expression of K+ leak channel(TASK1), and declines in proliferation, migration potential and glial progenitor population. The introduction of WJ-MSCs(after 2 h of reperfusion) through a non-contact method brought about significant improvement in all these cellular parameters as observed after 24hrs, and the PI3K pathway played an important role in the neuroprotection process. Presence of WJ-MSCs increased the expression of survival signals like phosphorylated Akt/Akt and PI3K in the OGD-reperfused NPs. Our data clearly demonstrate for the first time that soluble factors from WJ-MSCs can not only ameliorate survival, proliferation, migration and glial progenitor expression of OGD-reperfused NPs, but also regulate their intracellular Ca2+ response to KCl stimulation and expression of TASK1 through the PI3K pathway.