Department of Pharmacology, School of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
J Neurosci. 2012 Apr 4;32(14):4887-900. doi: 10.1523/JNEUROSCI.5828-11.2012.
17-β-estradiol (E2) is a steroid hormone involved in neuroprotection against excitotoxicity and other forms of brain injury. Through genomic and nongenomic mechanisms, E2 modulates neuronal excitability and signal transmission by regulating NMDA and non-NMDA receptors. However, the mechanisms and identity of the receptors involved remain unclear, even though studies have suggested that estrogen G-protein-coupled receptor 30 (GPR30) is linked to protection against ischemic injury. In the culture cortical neurons, treatment with E2 and the GPR30 agonist G1 for 45 min attenuated the excitotoxicity induced by NMDA exposure. The acute neuroprotection mediated by GPR30 is dependent on G-protein-coupled signals and ERK1/2 activation, but independent on transcription or translation. Knockdown of GPR30 using short hairpin RNAs (shRNAs) significantly reduced the E2-induced rapid neuroprotection. Patch-clamp recordings revealed that GPR30 activation depressed exogenous NMDA-elicited currents. Short-term GPR30 activation did not affect the expression of either NR2A- or NR2B-containing NMDARs; however, it depressed NR2B subunit phosphorylation at Ser-1303 by inhibiting the dephosphorylation of death-associated protein kinase 1 (DAPK1). DAPK1 knockdown using shRNAs significantly blocked NR2B subunit phosphorylation at Ser-1303 and abolished the GPR30-mediated depression of exogenous NMDA-elicited currents. Lateral ventricle injection of the GPR30 agonist G1 (0.2 μg) provided significant neuroprotection in the ovariectomized female mice subjected to middle cerebral artery occlusion. These findings provide direct evidence that fast neuroprotection by estradiol is partially mediated by GPR30 and the subsequent downregulation of NR2B-containing NMDARs. The modulation of DAPK1 activity by GPR30 may be an important mediator of estradiol-dependent neuroprotection.
17-β-雌二醇（E2）是一种参与神经保护作用的甾体激素，可以对抗兴奋毒性和其他形式的脑损伤。通过基因组和非基因组机制，E2 通过调节 NMDA 和非 NMDA 受体来调节神经元兴奋性和信号转导。然而，涉及的受体的机制和身份仍不清楚，尽管研究表明雌激素 G 蛋白偶联受体 30（GPR30）与对缺血性损伤的保护有关。在培养的皮质神经元中，用 E2 和 GPR30 激动剂 G1 处理 45 分钟可减轻 NMDA 暴露引起的兴奋毒性。GPR30 介导的急性神经保护作用依赖于 G 蛋白偶联信号和 ERK1/2 的激活，但不依赖于转录或翻译。使用短发夹 RNA（shRNA）敲低 GPR30 可显著降低 E2 诱导的快速神经保护作用。膜片钳记录显示，GPR30 激活可抑制外源性 NMDA 诱导的电流。短期 GPR30 激活不会影响含有 NR2A 或 NR2B 的 NMDA 受体的表达；然而，它通过抑制死亡相关蛋白激酶 1（DAPK1）的去磷酸化来抑制 NR2B 亚基磷酸化 Ser-1303。使用 shRNA 敲低 DAPK1 可显著阻断 NR2B 亚基磷酸化 Ser-1303，并消除 GPR30 介导的对外源性 NMDA 诱导电流的抑制作用。侧脑室注射 GPR30 激动剂 G1（0.2μg）可显著保护去卵巢雌性小鼠大脑中动脉闭塞后的神经。这些发现提供了直接证据，表明雌二醇的快速神经保护作用部分由 GPR30 介导，随后是 NR2B 含 NMDA 受体的下调。GPR30 对 DAPK1 活性的调节可能是雌二醇依赖性神经保护的重要介导者。
