Small RNA sequencing reveals microRNAs related to neuropathic pain in rats

The present study aimed to identify microRNAs (miRNAs) that are involved in neuropathic pain and predict their corresponding roles in the pathogenesis and development process of neuropathic pain. The rat model of neuropathic pain caused by spared nerve injury (SNI) was established in Sprague-Dawley male rats, followed by small RNA sequencing of the L3–L6 dorsal root ganglion. Real-time PCR was performed to validate the differently expressed miRNAs. Functional verification was performed by intrathecally injecting the animals with miRNA agomir. A total of 72 differentially expressed miRNAs were identified in the SNI rats, including 33 upregulated and 39 downregulated miRNAs. The results of qPCR further verified the expression levels of rno-miR-6215 (P=0.015), rno-miR-1224 (P=0.030), rno-miR-1249 (P=0.038), and rno-miR-488-3p (P=0.048), which were all significantly downregulated in the SNI rats compared to the control ones. The majority of differentially expressed miRNAs were associated with phosphorylation, intracellular signal transduction, and cell death. Target prediction, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses suggested that these differentially expressed miRNAs targeted genes that are related to axon guidance, focal adhesion, and Ras and Wnt signaling pathways. Moreover, miR-1224 agomir significantly alleviated SNI-induced neuropathic pain. The current findings provide new insights into the role of miRNAs in the pathogenesis of neuropathic pain.

本研究旨在筛选参与神经病理性疼痛的微小RNA（miRNAs），并预测其在神经病理性疼痛发生及发展过程中的相关作用。本研究采用雄性Sprague-Dawley（SD）大鼠构建保留神经损伤（spared nerve injury, SNI）所致神经病理性疼痛模型，对L3~L6段背根神经节进行小分子RNA测序。通过实时荧光定量PCR（Real-time PCR）验证差异表达miRNAs，并通过鞘内注射miRNA激动剂（agomir）开展功能验证实验。本研究在SNI模型大鼠中共鉴定出72个差异表达miRNAs，其中33个表达上调、39个表达下调。实时定量PCR（qPCR）结果进一步验证了rno-miR-6215（P=0.015）、rno-miR-1224（P=0.030）、rno-miR-1249（P=0.038）及rno-miR-488-3p（P=0.048）的表达水平，与对照组相比，上述miRNAs在SNI模型大鼠中均显著下调。大部分差异表达miRNAs与磷酸化修饰、细胞内信号转导及细胞死亡过程密切相关。靶基因预测、基因本体（GO）及京都基因与基因组百科全书（KEGG）通路富集分析结果显示，这些差异表达miRNAs的靶基因与轴突导向、黏着斑及Ras、Wnt信号通路相关。此外，miR-1224激动剂可显著缓解SNI诱导的神经病理性疼痛。本研究结果为阐明miRNAs在神经病理性疼痛发病机制中的作用提供了新的视角。