南方医科大学学报

南方医科大学学报 ›› 2017, Vol. 37 ›› Issue (12): 1620-.

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蛋白精氨酸甲基化酶在小鼠外周神经损伤后背根神经节中的转录表达

徐华丽，徐世元，磨凯   

  • 出版日期:2017-12-20 发布日期:2017-12-20

Transcription of protein arginine N-methyltransferase genes in mouse dorsal root ganglia following peripheral nerve injury

  • Online:2017-12-20 Published:2017-12-20

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摘要： 目的探讨蛋白精氨酸甲基化酶（PRMT）在外周神经损伤背根神经节（DRG）转录表达与疼痛行为关系。方法构建 C57BL6小鼠双侧L4脊神经结扎（SNL）外周神经损伤神经病理性疼痛模型，假手术Sham组作对照，收集SNL或Sham术后第7 天DRG组织，行RNA-Seq测序全面分析PRMT家族9个基因在转录表达规律和组织分布情况，筛选出差异表达基因；建立小鼠 单侧L4 SNL模型（Sham组作对照），测量各组在SNL术前（0 d）、术后3、7和14 d不同时点机械缩爪反应频率（PWF）和热缩爪反 应潜伏期（PWL），收集两组上述不同时点患侧和对侧DRG行RT-qPCR验证差异基因表达情况；建立坐骨神经结扎慢性缩窄损 伤（CCI）模型，假手术组Sham作对照，疼痛行为检测方法和时间点同SNL模型，RT-qPCR进一步验证CCI术后上述时点差异基 因表达情况。结果（1）RNA-Seq测序结果表明，9个PRMT基因均表达与DRG内，其基础表达量最多的是Prmt2和Prmt3，最少 的是Prmt6。与Sham组比较，SNL神经损伤上调DRG Carm1转录表达（增加1.7倍），抑制Prmt5、Prmt8和Prmt9这3个基因转 录，其中Prmt8抑制最明显（下降16.3倍）。（2）RT-qPCR验证表明，与Sham组较，SNL外周神经损伤增加术后3、7和14 d PWF， 降低PWL，上调DRG Carm1转录表达，而仅抑制Prmt8转录表达，Prmt1、Prmt5和Prmt9无明显改变。（3）同样的，CCI坐骨神经 损伤亦增加CCI术后3、7和14 d PWF，降低PWL，上调DRG Carm1，抑制Prmt8在上述时点的表达。结论外周神经损伤致机 械痛觉高敏和热痛觉过敏的同时，上调DRG Carm1转录表达，抑制Prmt8基因转录。

Abstract: Objective To investigate the changes in the transcription of protein arginine methylation enzyme family genes in the dorsal root ganglia (DRG) following peripheral nerve injury in mice. Methods C57BL6 mouse models of neuropathic pain induced by peripheral nerve injury were established by bilateral L4 spinal nerve ligation (SNL). At 7 days after SNL or sham operation, the DRG tissue was collected for transcriptional analysis of 9 protein arginine methylation enzyme genes (Prmt1-3, Carm1, and Prmt5-9) using RNA-Seq to identify the differentially expressed genes in the injured DRGs. We also established mouse models of lateral L4 SNL and models of chronic constriction injury (CCI) of the sciatic nerve and tested the paw withdrawal frequency (PWF) in response to mechanical stimulation and paw withdrawal latency (PWL) in response to thermal stimulation on 0, 3, 7 and 14 days after SNL or CCI; the expressions of the differentially expressed genes in the injured DRGs were verified in the two models using RT-qPCR. Results Among the 9 protein arginine methylation enzyme family genes that were tissue-specifically expressed in the DRG, Prmt2 and Prmt3 showed the highest and Prmt6 showed the lowest basal expression. Compared with the sham-operated mice group, the mice receiving SNL exhibited upregulated Carm1 gene transcription (by 1.7 folds) but downregulated Prmt5, Prmt8 and Prmt9 transcription in the injured DRG (Prmt8 gene showed the most significant down-regulation by 16.3 folds). In mouse models of SNL and CCI, Carm1 gene expression increased progressively with time while Prmt8 transcription was obviously lowered on days 3, 7 and 14 after the injury; the transcription levels of Prmt1, Prmt5 and Prmt9 presented with no significant changes following the injuries. Both SNL and CCI induced mechanical allodynia and thermal hypersensitivities in the mice shown by increased PWF and decreased PWL on days 3, 7 and 14 after the injuries. Conclusion Periphery nerve injury induces Carm1 upregulation and Prmt8 downregulation in the injured DRG in mice, which sheds light on new targets for treatment of neuropathic pain.