背根神经节NMDA受体介导的Epac1/Piezo2信号通路在骨癌痛中的作用及其机制研究

机械性痛觉过敏是骨癌痛的主要特点之一，临床尚缺乏有效治疗手段。近期研究发现，背根神经节（DRG）神经元中新型机械敏感离子通道Piezo2以Epac1（cAMP直接激活的交换蛋白1）依赖的方式参与机械性痛敏的形成，而细胞内钙离子浓度（[Ca2+]i）是该信号通路活化的关键。有研究提示，作为调节 [Ca2+]i、参与疼痛信号传导的关键受体，NMDA受体受到Epac1的正性调节。课题组预实验发现，骨癌痛小鼠患侧DRG神经元中Epac1和NR2B表达增加。因此，我们推测：Epac1可能通过NMDA受体介导对[Ca2+]i的调节，进而影响Piezo2功能，参与骨癌痛机械性痛敏的形成。本研究拟在离体培养神经元和小鼠骨癌痛模型上应用分子生物学、行为学、RNA干扰、钙离子成像、DRG局部注射等技术手段，探讨NMDA受体介导的Epac1/Piezo2信号通路在骨癌痛机械性痛敏中的作用及其机制。

Mechanical allodynia is one of the main characteristics of bone cancer pain and short of efficient cure measures. Recent studies have found that Piezo2, a novel mechanosensitive ion channel, has a role in the development of mechanical allodynia in Epac1-dependent manner, which depends on intracellular Ca2+ concentration. It has been suggested that NMDA receptor, known as a key receptor in the regulation of intracellular Ca2+ concentration and pain signal tranduction, is positive regulated by Epac1. Our preliminary experiments observed that Epac1 and NR2B proteins in dorsal root ganglion increase during bone cancer pain. Thus, we propose the hypothesis that Epac1 potentiation of NMDA-mediated regulation of intracellular Ca2+ concentration sensitizes Piezo2 leading to mechanical allodynia of bone cancer pain. To test this hypothesis, we will investigate the role of NMDA-mediated Epac1/Piezo2 pathway in the dorsal root ganglion in the development of bone cancer pain by molecular biotechnology, behavior, RNA interference, calcium imaging, direct injection into DRG and other technological means.