The present study explored the effects of endophilin A1 (SH3GL2) against oxidative damage brought about by H2O2 in HT22 cells and ischemic damage induced upon transient forebrain
ischemia in gerbils. Tat-SH3GL2 and its control
protein (Control-SH3GL2) were synthesized to deliver it to the cells by penetrating the cell membrane and blood-brain barrier. Tat-SH3GL2, but not Control-SH3GL2, could be delivered into HT22 cells in a concentration- and time-dependent manner and the hippocampus 8 h
after treatment in gerbils. Tat-SH3GL2 was stably present in HT22 cells and degraded with time, by 36 h post treatment. Pre-incubation with Tat-SH3GL2, but not Control-SH3GL2, significantly ameliorated H2O2-induced cell death, DNA fragmentation, and
reactive oxygen species formation. SH3GL2 immunoreactivity was decreased in the gerbil hippocampal CA1 region with time after
ischemia, but it was maintained in the other regions after
ischemia. Tat-SH3GL2 treatment in gerbils appreciably improved
ischemia-induced hyperactivity 1 day after
ischemia and the percentage of NeuN-immunoreactive surviving cells increased 4 days after
ischemia. In addition, Tat-SH3GL2 treatment in gerbils alleviated the increase in lipid peroxidation as assessed by the levels of
malondialdehyde and 8-iso-prostaglandin F2α and in pro-inflammatory
cytokines such as
tumor necrosis factor-α, interleukin-1β, and
interleukin-6; while the reduction of
protein levels in markers for synaptic plasticity, such as postsynaptic density 95,
synaptophysin, and synaptosome associated
protein 25 after transient forebrain
ischemia was also observed. These results suggest that Tat-SH3GL2 protects neurons from oxidative and ischemic damage by reducing lipid peroxidation and
inflammation and improving synaptic plasticity after
ischemia.