Transcriptomic differential lncRNA expression is involved in neuropathic pain in rat dorsal root ganglion after spared sciatic nerve injury

Dorsal root ganglia (DRG) neurons regenerate spontaneously after traumatic or surgical injury. Long noncoding RNAs (lncRNAs) are involved in various biological regulation processes. Conditions of lncRNAs in DRG neuron injury deserve to be further investigated. Transcriptomic analysis was performed by high-throughput Illumina HiSeq2500 sequencing to profile the differential genes in L4–L6 DRGs following rat sciatic nerve tying. A total of 1,228 genes were up-regulated and 1,415 down-regulated. By comparing to rat lncRNA database, 86 known and 26 novel lncRNA genes were found to be differential. The 86 known lncRNA genes modulated 866 target genes subject to gene ontology (GO) and KEGG enrichment analysis. The genes involved in the neurotransmitter status of neurons were downregulated and those involved in a neuronal regeneration were upregulated. Known lncRNA gene rno-Cntnap2 was downregulated. There were 13 credible GO terms for the rno-Cntnap2 gene, which had a putative function in cell component of voltage-gated potassium channel complex on the cell surface for neurites. In 26 novel lncRNA genes, 4 were related to 21 mRNA genes. A novel lncRNA gene AC111653.1 improved rno-Hypm synthesizing huntingtin during sciatic nerve regeneration. Real time qPCR results attested the down-regulation of rno-Cntnap lncRNA gene and the upregulation of AC111653.1 lncRNA gene. A total of 26 novel lncRNAs were found. Known lncRNA gene rno-Cntnap2 and novel lncRNA AC111653.1 were involved in neuropathic pain of DRGs after spared sciatic nerve injury. They contributed to peripheral nerve regeneration via the putative mechanisms.

背根神经节（Dorsal root ganglia, DRG）神经元在创伤或手术损伤后可自发再生。长链非编码RNA（Long noncoding RNAs, lncRNAs）参与多种生物调控过程，而DRG神经元损伤状态下的lncRNAs表达特征仍有待进一步探究。本研究通过高通量Illumina HiSeq2500测序开展转录组分析，对大鼠坐骨神经结扎后L4~L6节段DRG中的差异表达基因进行表达谱构建。结果共筛选得到1228个上调基因与1415个下调基因。通过比对大鼠lncRNA数据库，鉴定出86个已知差异lncRNA基因与26个新型差异lncRNA基因。针对86个已知差异lncRNA基因所调控的866个靶基因，本研究开展了基因本体（Gene ontology, GO）富集分析与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）富集分析。分析结果显示，与神经元神经递质状态相关的基因呈下调趋势，而参与神经元再生过程的基因则呈上调趋势。已知差异lncRNA基因rno-Cntnap2呈现下调表达，该基因共涉及13个可信GO条目，其推测功能与神经元突起细胞膜表面的电压门控钾通道复合物的细胞组分相关。在26个新型差异lncRNA基因中，有4个基因与21个mRNA基因存在调控关联。新型lncRNA基因AC111653.1可调控大鼠亨廷顿蛋白编码基因rno-Hypm的表达，参与坐骨神经再生过程。实时定量qPCR（Real time qPCR）实验验证了rno-Cntnap2 lncRNA基因的下调表达与AC111653.1 lncRNA基因的上调表达。本研究共鉴定得到26个新型lncRNA，其中已知lncRNA基因rno-Cntnap2与新型lncRNA AC111653.1均参与保留性坐骨神经损伤（spared sciatic nerve injury）后DRG相关的神经病理性疼痛过程，并通过潜在调控机制参与外周神经再生。