1 Department of Anesthesiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
Mol Pain. 2019 Jan-Dec;15:1744806918824250. doi: 10.1177/1744806918824250.
Bone cancer pain is one of the most severe and intractable complications in patients suffering from primary or metastatic bone cancer and profoundly compromises the quality of life. Emerging evidence indicates that the dorsal root ganglion play an integral role in the modulation of pain hypersensitivity. However, the underlying molecular mechanisms during dorsal root ganglion-mediated bone cancer pain remain elusive. In this study, RNA-sequencing was used to detect the differentially expressed genes in dorsal root ganglion neurons of a rat bone cancer pain model established by intratibial inoculation of Walker 256 breast cancer cells. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis showed that the differentially expressed genes (fold change > 1.5; false discovery rate < 0.05) were enriched in the bone morphogenetic protein (BMP) signaling pathway, transforming growth factor-β signaling pathway, and positive regulation of cartilage development. Importantly, serum deprivation-response protein ( Sdpr), hephaestin ( Heph), transthyretin ( Ttr), insulin receptor substrate 1 ( Irs1), connective tissue growth factor ( Ctgf ), and Bmp2 genes were associated with bone pain and degeneration. Of note, Bmp2, a pleiotropic and secreted molecule mediating pain and inflammation, was one of the most significantly upregulated genes in dorsal root ganglion neurons in this bone cancer pain model. Consistent with these data, upregulation of Bmp2 in the bone cancer pain model was validated by immunohistochemistry, real-time quantitative polymerase chain reaction, and western blotting. Importantly, intrathecal administration of siRNA significantly reduced Bmp2 transcription and ameliorated bone cancer pain in rat as shown by paw withdrawal mechanical threshold and spontaneous and movement-evoked pain-like behaviors. In conclusion, we have characterized the comprehensive gene expression profile of dorsal root ganglion from a bone cancer pain rat model by RNA-sequencing and identified Bmp2 as a potential therapeutic target for bone cancer pain treatment.
骨癌疼痛是原发性或转移性骨癌患者最严重和最顽固的并发症之一，严重降低了患者的生活质量。新出现的证据表明，背根神经节在疼痛敏化的调节中起着不可或缺的作用。然而，背根神经节介导的骨癌疼痛背后的潜在分子机制仍不清楚。在这项研究中，我们通过向大鼠胫骨内接种 Walker 256 乳腺癌细胞建立骨癌疼痛模型，使用 RNA 测序检测背根神经节神经元中的差异表达基因。基因本体论和京都基因与基因组百科全书分析表明，差异表达基因（倍数变化>1.5；错误发现率<0.05）富集在骨形态发生蛋白（BMP）信号通路、转化生长因子-β信号通路和软骨发育的正调控中。重要的是，血清剥夺反应蛋白（Sdpr）、赫菲斯塔因（Heph）、转甲状腺素蛋白（Ttr）、胰岛素受体底物 1（Irs1）、结缔组织生长因子（Ctgf）和 Bmp2 基因与骨痛和骨退化有关。值得注意的是，Bmp2 是一种多效性和分泌性分子，介导疼痛和炎症，是这种骨癌疼痛模型中背根神经节神经元中上调最显著的基因之一。与这些数据一致，免疫组织化学、实时定量聚合酶链反应和蛋白质印迹验证了骨癌疼痛模型中 Bmp2 的上调。重要的是，鞘内给予 siRNA 可显著降低 Bmp2 的转录，并改善大鼠的骨癌疼痛，表现为足底撤回机械阈值和自发性及运动诱发的疼痛样行为改善。总之，我们通过 RNA 测序对骨癌疼痛大鼠模型的背根神经节进行了全面的基因表达谱分析，并确定 Bmp2 是骨癌疼痛治疗的潜在治疗靶点。
