UCH-L1调节cAMP-PKA-CREB通路介导骨癌痛的脊髓机制研究

The regulation of pain-related factors by ubiquitin-proteasome system is becoming the new hot spot in the research of pain mechanism. Previous studies have confirmed that, expression of UCH-L1 were selectively increased within the ipsilateral dorsal horn of neuropathic rats, but the specific mechanism is still unclear. Whether UCH-L1 is involved in the regulation of cancer pain has not yet been reported. Preliminary experiments proved that the expression level of UCH-L1, monomeric ubiquitin and PKA increased in the spinal cord of bone cancer pain rats, which can be attenuated by intrathecal injection of UCH-L1-siRNA , the siRNA also can decrease the hyperalgia in bone cancer pain rats. We will use a variety of experimental methods, including behavioral tests, biochemistry, electrophysiology, neurobiology and molecular biology, to investigate the regulatory and mechanisms of UCH-L1 to the cAMP-PKA-CREB signaling pathway in the spinal cord and dorsal root ganglion, and its role in rat tibial bone cancer pain model. The completion of this study will expound the pathogenesis of bone cancer pain from a new angle, and will provide the theory basis and the new ideas for drug development in the treatment of cancer pain.

泛素-蛋白酶体系统（ubiquitin-proteasome system，UPS）对疼痛相关因子的调控机制是当前研究的新热点。已有的研究证实：在神经病理性疼痛大鼠脊髓，泛素C末端水解酶-L1（ubiquitin C-terminal hydrolases-L1，UCH-L1）上调，但其具体机制尚不清楚，且UCH-L1是否参与调节癌性疼痛未见报道。预实验证实：胫骨癌痛大鼠脊髓UCH-L1、单体泛素、PKA表达上调；鞘内注射UCH-L1-siRNA可以下调UCH-L1、单体泛素和PKA的表达，减轻痛觉过敏。我们拟采用行为学、生物化学、电生理、神经生物学和分子生物学等方法，进一步研究脊髓和背根神经节UCH-L1对cAMP-PKA-CREB通路的调控和机制，及其在大鼠胫骨癌痛发病中的作用。该研究有助于阐明骨癌痛的发病机制，为治疗骨癌痛药物的开发提供理论依据和新的思路。

肿瘤细胞转移导致的骨痛是医学领域的挑战性研究课题，疼痛相关信号通路的调控是其中的热点。泛素-蛋白酶体系统（ubiquitin-proteasome system，UPS）对疼痛相关因子的调控机制是当前研究的新热点。在胫骨癌痛大鼠脊髓中，随着痛觉过敏的发生，我们首次在脊髓应用免疫荧光双标技术定位UCHL1/ubiquitin---neuron、GFAP、Iba-1双标情况，证实其存在不同的亚细胞分布。进一步的，我们发现在骨癌痛发病中，脊髓UCH-L1、单体泛素、PKA、CREB、胶质细胞激活出现同步改变。脊髓水平抑制UCH-L1可以通过抑制泛素、PKA、CREB和胶质细胞激活，减轻痛觉过敏。最近的研究提示：自噬系统和蛋白酶体系统之间可以相互联系。我们研究发现：SNL大鼠脊髓 LC3-II、p62 表达增高。Rap上调自噬能减轻疼痛，而3-MA抑制自噬加重痛敏，其机制与脊髓背角小胶质细胞自噬、LC3-II/LC3-I和IL-1β的影响有关。在脊髓定为标记UCHL1/ ubiquitin、mTOR、P62。随着痛敏的发生，脊髓UCH-L1、单体泛素、mTOR、P62上调。脊髓上水平抑制UCH-L1可以减少UCHL1活性、单体泛素、mTOR、P62，进而发挥较强的镇痛作用。