The Department of Pharmacology, The University of Melbourne, Parkville, Victoria 3010, Australia.
Neuropharmacology. 2010 Nov;59(6):416-24. doi: 10.1016/j.neuropharm.2010.05.014. Epub 2010 Jun 9.
Although sigma 1 (σ(1)) receptors and mitogen-activated protein kinases (MAPKs) are known modulators of neuroprotection, a role for MAPK signaling pathways in σ receptor-mediated neuroprotection has not been investigated in detail.The present study aims to investigate the possible link between σ(1) receptors and MAPKs in neuroprotection. Primary mixed cortical and hippocampal neurons were treated with σ(1) receptor agonists PRE-084 or 4-PPBP in a time- and concentration-dependent manner; and in another set of experiments, cells were pre-incubated with σ(1) receptor antagonist BD1047 or MEK inhibitor PD98059 in a concentration-dependent manner prior to PRE-084 or 4-PPBP treatment. Levels of phosphorylated and total ERK1/2, JNK and p38-MAPK were determined with western blotting and ERK1/2 phosphorylation was confirmed with immunofluorescence. To investigate neuroprotection by σ(1) receptors, cells were pre-treated with PRE-084 or 4-PPBP and glucose-starved for various times: in the presence or absence of pre-incubated BD1047 or PD98059. Cell viability was then measured with MTT assay. Both PRE-084 and 4-PPBP caused phosphorylation of ERK1/2, but not p38-MAPK and JNK. ERK1/2 phosphorylation was inhibited by BD1047 and PD98059 in a concentration-dependent manner. Immunofluorescence confirmed the phosphorylation of ERK1/2 by PRE-084 and 4-PPBP and its inhibition by BD1047 and PD98059. Pre-treating glucose-deprived neurons with 4-PPBP, but not PRE-084; caused neuroprotection which was inhibited by BD1047 and PD98059. 4-PPBP, but not PRE-084; causes ERK1/2 phosphorylation-mediated neuroprotection. This presents a novel mechanism by σ(1) receptors in modulating neuroprotection.
虽然西格玛 1（σ（1））受体和丝裂原活化蛋白激酶（MAPKs）是神经保护的已知调节剂，但 MAPK 信号通路在 σ 受体介导的神经保护中的作用尚未得到详细研究。本研究旨在探讨 σ（1）受体与 MAPKs 在神经保护中的可能联系。原代混合皮质和海马神经元以时间和浓度依赖的方式用 σ（1）受体激动剂 PRE-084 或 4-PPBP 处理；在另一组实验中，细胞用 σ（1）受体拮抗剂 BD1047 或 MEK 抑制剂 PD98059 以浓度依赖的方式预孵育，然后用 PRE-084 或 4-PPBP 处理。用 Western blot 测定磷酸化和总 ERK1/2、JNK 和 p38-MAPK 的水平，并通过免疫荧光证实 ERK1/2 的磷酸化。为了研究 σ（1）受体的神经保护作用，用 PRE-084 或 4-PPBP 预处理细胞，并进行不同时间的葡萄糖饥饿：有无预孵育的 BD1047 或 PD98059。然后用 MTT 测定细胞活力。PRE-084 和 4-PPBP 均导致 ERK1/2 的磷酸化，但不导致 p38-MAPK 和 JNK 的磷酸化。ERK1/2 的磷酸化被 BD1047 和 PD98059 以浓度依赖的方式抑制。免疫荧光证实了 PRE-084 和 4-PPBP 对 ERK1/2 的磷酸化及其被 BD1047 和 PD98059 的抑制作用。用 4-PPBP 预处理葡萄糖剥夺的神经元，但不是 PRE-084；引起神经保护作用，该作用被 BD1047 和 PD98059 抑制。4-PPBP 而非 PRE-084 引起 ERK1/2 磷酸化介导的神经保护作用。这提出了 σ（1）受体调节神经保护的一种新机制。
