Phosphoglycerate kinase 1 protects against ischemic damage in the gerbil hippocampus

Phosphoglycerate kinase 1 (PGK1) is a metabolic enzyme that converts 1,3-diphosphoglycerate to 3phosphoglycerate. In the current study, we synthesized a PEP-1-PGK1 fusion protein that can cross the bloodbrain barrier and cell membrane, and the effects of PEP-1-PGK1 against oxidative stress were investigated HT22 cells and ischemic gerbil brain. The PEP-1-PGK1 protein and its control protein (Con-PGK1) were treated and permeability was evaluated HT22 cells. The PEP-1-PGK1 was introduced into HT22 cells depending on its concentration and incubation time and was gradually degraded over 36 h after treatment. PEP-1-PGK1, but not Con-PGK1, significantly ameliorated H2O2-induced cell damage and reactive oxygen species formation in HT22 cells. Additionally, PEP-1-PGK1, but not Con-PGK1, mitigated ischemia-induced hyperlocomotion 1 d after ischemia and 4 d after ischemia of neuronic cell death. PEP-1-PGK1 treatment significantly alleviated the raised lactate and succinate dehydrogenase activities in the early (15 min to 6 h) and late (4 and 7 d) stages of ischemia, respectively. In addition, PEP-1-PGK1 treatment ameliorated the decrease in ATP and pH levels in the late stage (2-7 d) of ischemia. Nuclear factor erythroid-2-related factor 2 (Nrf2) levels accelerated the ischemiainduced increase in the hippocampus 1 d after ischemia after PEP-1-PGK1 treatment. Neuroprotective and ameliorative effects were prominent at a low concentration (0.1 mg/kg), but not at a high concentration (1 mg/kg), of PEP-1-PGK1. Collectively, low concentrations of PEP-1-PGK1 prevented neuronal stress by increasing energy production.