基于JMJD6的表观遗传调控网络在神经病理性疼痛中的作用研究

Neuropathic pain is refractory and protracted. How to effectively treat this disease has become a challenge in the present medical field. We found that histone modification has influence on the prognosis of neuropathic pain via regulating the plastic expressions of the downstreen genes. JMJD6 is a newly found histone demethylase, and it also inhibits the transcriptional activities of HIF-1α on many pain genes, so we speculate that JMJD6 may regulate the processes of neuropathic pain through these epigenetic mechanism. In the preliminary experiment, we found that the expression of JMJD6 on the spinal cord decreased in neuropathic pain rats. And there was obviously pain relief on neuropathic pain rats after intrathecal injection with JMJD6 over-expression vector. In order to further verify the therapeutic effect and detailed mechanism of JMJD6 on neuropathic pain, we plan to investigate the dynamic spatiotemporal expression of JMJD6 on spinal cord and dorsal root ganglion, observe it’s influence on pain behavior and electrophysiological characteristics, explore the functional relations of JMJD6 with histone demethylation and HIF-1α, and its effect on the expressions of downstream genes in vivo and in vitro. The objective of this project is to clarify the role of JMJD6’s epigenetic network on neuropathic pain, and provide the foundation for the discovery of new neuropathic pain therapeutic target.

神经病理性疼痛迁延难愈，目前尚缺乏有效治疗手段。我们前期研究发现组蛋白修饰通过调控下游疼痛基因的可塑性表达影响神经病理性疼痛的转归。JMJD6是近年来发现的组蛋白去甲基化酶，也具有抑制转录因子HIF-1α转录活性的功能，推测它可能通过上述表观遗传机制调控神经病理性疼痛的进程。通过预实验我们发现神经病理性疼痛大鼠脊髓JMJD6的表达水平明显降低，鞘内注射JMJD6过表达载体恢复其表达后，大鼠的疼痛行为显著缓解，初步证实了以上推测。为进一步明确JMJD6对神经病理性疼痛的作用及潜在机制，本项目拟研究JMJD6在脊髓和背根神经节的动态时空表达变化，观察其对疼痛行为和神经电生理的影响，经体内体外实验探索JMJD6与组蛋白去甲基化修饰和HIF-1α的作用关系，以及对相应下游疼痛基因表达的影响，最终阐明JMJD6的表观遗传调控网络在神经病理性疼痛中的作用机制，为发现新的神经病理性疼痛治疗靶点奠定基础。

神经病理性疼痛发病率高，难治愈。但由于对神经病理性疼痛发病机制认识不清，至今仍缺乏特异有效的治疗手段。组蛋白修饰可以通过调控下游疼痛基因的可塑性表达从而影响神经病理性疼痛的转归。本项目中，我们研究了组蛋白去甲基化转移酶JMJD6在神经病理性疼痛中的作用。我们首次发现了JMJD6在CCI导致的神经病理性疼痛大鼠脊髓中表达下降，JMJD6在脊髓背角浅层表达尤为密集，且主要表达在神经元内。鞘内注射JMJD6过表达慢病毒载体，CCI大鼠在给药后第7天机械痛和热痛有明显的缓解。外周神经损伤时，JMJD6进入胞核发挥作用的水平下降，其胞核内组蛋白去甲基化水平降低，导致其可能通过HIF-1α，NF-κB等通路调节下游疼痛因子的转录水平变化。因此我们探索了JMJD6与组蛋白H4R3去甲基化水平的关系，研究发现CCI术后第7天，第14天去甲基化水平降低，鞘内给予JMJD6慢病毒载体后， CCI大鼠脊髓H4R3位点去甲基化水平升高，提示JMJD6很可能是通过去甲基化酶活性影响组蛋白各位点的甲基化水平。最后我们阐明了JMJD6通过HIF-1α， NF-κB等通路表观调控神经病理性疼痛的发展和维持。上述研究为发现新的神经病理性疼痛治疗靶点奠定基础。