Gene expression profiling of ipsilateral dorsal root ganglia of bone cancer pain in a rat model

Objectives: This study aimed to identify a set of differentially expressed genes (DEGs) in dorsal root ganglions (DRGs) between bone cancer pain (BCP) and sham BCP rats using RNA-sequencing (RNA-Seq). Methods: We established a rat BCP model by implanting MRMT-1 cells into the bone marrow cavity of left tibia. RNA-Seq was used to screen related genes. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and protein-protein interaction (PPI) network analysis were conducted to investigate the bioinformatics functions of DEGs and possible potential pathological mechanisms of BCP. Results: RNA-Seq of ipsilateral DRGs from model rats identified a total of 152 DEGs compared to sBCP rats. The expression changes of four randomly selected DEGs were verified by qPCR. Four significant signaling pathways have been found for BCP including MAPK signaling pathway, calcium signaling pathway, apelin signaling pathway and oxytocin signaling pathway. Cxcl13 in DRGs was identified as a key player in the BCP model by comparing with published datasets in classic pain models. A core set of genes contributed to BCP mechanism were sorted out by PPI network analysis. Conclusions: These altered mRNAs and signaling pathways might be potential therapeutic targets for BCP treatment, which can guide future research on the molecular mechanism of BCP.研究目的：本研究旨在通过RNA测序（RNA-sequencing, RNA-Seq），鉴定骨癌痛（bone cancer pain, BCP）模型大鼠与假手术骨癌痛（sham BCP）大鼠背根神经节（dorsal root ganglions, DRGs）中的差异表达基因（differentially expressed genes, DEGs）集合。 方法：本研究通过向大鼠左侧胫骨骨髓腔植入MRMT-1细胞，构建大鼠骨癌痛模型。采用RNA-seq技术筛选相关差异表达基因，并通过基因本体论（Gene Ontology, GO）、京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）富集分析以及蛋白质-蛋白质相互作用（protein-protein interaction, PPI）网络分析，探究差异表达基因的生物信息学功能及骨癌痛潜在的病理机制。 结果：与假手术组（sBCP）大鼠相比，模型组大鼠同侧背根神经节的RNA-seq分析共鉴定出152个差异表达基因。随机选取4个差异表达基因，通过qPCR（实时定量聚合酶链反应）验证了其表达变化。本研究共筛选出与骨癌痛相关的4条显著信号通路，分别为丝裂原活化蛋白激酶（mitogen-activated protein kinase, MAPK）信号通路、钙信号通路、apelin信号通路以及催产素信号通路。通过与经典疼痛模型的已发表数据集进行比对，鉴定出背根神经节中的Cxcl13为骨癌痛模型中的关键调控因子。经PPI网络分析，筛选出一组参与骨癌痛发生机制的核心基因集。 结论：这些差异表达的mRNA及信号通路或可作为骨癌痛治疗的潜在靶点，可为未来骨癌痛分子机制的相关研究提供指导。