Evaluating In Vitro Neonatal Hypoxic-Ischemic Injury Using Neural Progenitors Derived from Human Embryonic Stem Cells

In hypoxic-ischemic encephalopathy, the neural progenitors (NPs) of the developing brain fail to replenish the oligodendrocyte progenitor cells lost during hypoxic-ischemic injury (HII). In this study, we aim to examine the influence of HII on the vulnerability of human NPs derived from human embryonic stem cells with regard to cell survival and oxidative stress, followed by assessment of cellular deregulation through measuring glutathione levels, basal calcium, glutamate release, and intracellular calcium ([Ca²⁺]_i) response under KCl and ATP stimulation. NPs were further evaluated for their fundamental potential of self-renewal and proliferation, neural and glial progenitor pool, and migration. Oxygen-glucose deprivation (OGD) of 90 min was sublethal for NPs, yet significantly increased reactive oxygen species generation and oxidative stress susceptibility, and decreased glutathione levels, along with a rise in glutamate release, basal [Ca²⁺]_i, and KCl and ATP-induced [Ca²⁺]_i. Distinct increase in gene expression for K⁺ leak channel (Twik-related acid-sensitive K⁺ channel 1 [TASK-1]) and purinergic receptor P2X7, and decrease of voltage-gated K_v channels K, K, and K were observed. TASK-1 increase was detected by FACS too. OGD-insulted NPs showed reduced migration potential and decline in glial progenitor population. This study thus demonstrates for the first time that brief exposure of OGD does not reduce the NP population, its proliferation, and self-renewal, but can induce significant alteration in oxidative stress susceptibility, glutamate release, [Ca²⁺]_i response to physiological stimulus, migration, and glial progenitor pool. We thus infer that treatment strategies need to target repair of NPs of the developing brain that is affected during intrapartum asphyxia, leading to varying neurologic complications such as seizure, mental retardation, and/or cerebral palsy.