Neuroprotective effects of oestrogen against oxidative toxicity through activation of G-protein-coupled receptor 30 receptor

1. 17-beta-oestradiol (E2) plays a critical role in neuroprotection through both genomic and non-genomic mechanisms. The aim of the present study was to investigate the role of G-protein-coupled receptor 30 (GPR30), a new kind of oestrogen receptor, in the neuroprotection against oxidative insult. 2. The neuroprotection evoked by GPR30 stimulation was examined in cultured cortical neurons. Hoechst 33258/propidium iodide double staining, flow cytometric analysis and western blotting were applied to assess neuronal apoptosis induced by H2O2. 3. We found that the GPR30 agonist, G1, and E2 attenuated apoptosis induced by H2O2 exposure. Furthermore, G1 (1 nmol/L) or E2 (1 nmol/L) significantly increased the levels of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), Bcl-2 and pro-caspase-3. Pretreatment with ICI182780, a highly selective nuclear oestrogen receptor antagonist that is used to block the classical ER alpha and ER beta receptors, did not totally block the neuroprotective effects of E2 (1 nmol/L) and had no effect on the neuroprotective effects of G1 (1 nmol/L). 4. Our data suggest that GPR30 is involved in the neuroprotection against oxidative insult. The neuroprotection evoked by GPR30 stimulation was associated with the signalling through the ERK1/2 kinase pathway. In addition, the anti-apoptotic activity of GPR30 was dependent on the expression of Bcl-2 and pro-caspase-3. GPR30 might be a potential therapeutic target for neuroprotection and oxidative stress.