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

1. 17-β-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 H(2)O(2) . 3. We found that the GPR30 agonist, G1, and E2 attenuated apoptosis induced by H(2)O(2) 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 ERα and ERβ 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.