基于全长转录组分析探讨熊果酸抗癫痫和神经保护的机制

Antiepileptic and neuroprotective mechanism of ursolic acid based on fulllength transcriptome analysis

基于转录组分析探讨熊果酸(ursolic acid,UA)抗癫痫和改善癫痫诱导的GABAergic神经元损伤的可能机制。选取对照组(NC组)、癫痫组(SE组)及癫痫UA给药组(UA组)大鼠的海马组织进行全长转录组测序;测序数据利用GO(gene ontology,GO)、KEGG(kyoto encyclopedia of genes and genomes,KEGG)及PPI(protein-protein interaction networks,PPI)对差异基因(differential genes,DEGs)进行分析;利用RT-qPCR验证海马组织中关键差异基因的表达量;最后在原代神经元上构建体外癫痫模型,采用RT-qPCR对差异基因的表达量进行验证,并利用免疫荧光、Western blot进一步检测神经元上GABAA受体γ2亚基(GABRG2)的表达量。两两样本表达量相关性热图及DEGs聚类分析结果显示:SE组距离NC组最远,UA治疗后,总体向正常组偏移。SE组与UA组对比,共筛选出220个差异基因,其中143个基因上调,77个基因下调。GO富集分析显示:在一级分类中涉及生物过程、细胞成分和分子功能3个过程。KEGG通路富集分析表明,DEGs涉及cAMP信号通路、钙信号通路等36条生物学通路。PPI分析表明DEGs与GABA及炎症关系密切。RT-qPCR结果表明UA处理增加了海马组织中GABA受体相关基因(Gng4)、GABA合成相关基因(Camk2a、Vgf和Npy)、炎症相关基因(Timp1和Spp1)的表达量,降低了GABA合成相关基因(Nptx2)、cAMP相关通路基因(Gnas)的表达量;并进一步证实UA处理增加了神经元上Gng4、Camk2a的表达量,降低了Gnas的表达量。免疫荧光与Western blot结果显示,与SE组相比,UA给药后原代神经元上GABRG2的表达量增加。本研究丰富了UA抗癫痫的转录组数据,也为深入研究UA抗癫痫和神经保护奠定理论基础。

This study explores the potential antiepileptic mechanism of ursolic acid(UA)and its improvement of GABAergic interneuron damage induced by epilepsy based on transcriptome analysis.Hippocampal tissues from rats in the control group(NC group),epilepsy group(SE group),and epilepsy UA treatment group(UA group)were subjected to full-length transcriptome sequencing.The obtained sequencing data were analyzed,using gene ontology(GO),the Kyoto Encyclopedia of Genes and Genomes(KEGG),and protein-protein interaction(PPI)to perform the analysis of differential genes(DEGs).The expression levels of key differential genes were verified using RT-qPCR in hippocampal tissue.Finally,an epilepsy in vitro model was constructed on primary neurons,RT-qPCR was used to verify the expression levels of key differential genes,and the expression level of GABAA receptorγ2 subunit(GABRG2)on neurons was further examined using immunofluorescence and Western blot.The heatmap of pairwise sample expression correlation and the clustering analysis of differentially expressed genes showed that the SE group was farthest from the NC group,and that after UA treatment,the overall trend shifted towards the normal group.Compared with the SE group,a total of 220 differential genes were screened in the UA group,including 143 upregulated genes and 77 downregulated genes.GO enrichment analysis showed that it involved three processes in the primary classification:biological processes,cellular components,and molecular functions.KEGG pathway enrichment analysis showed that DEGs were involved in 36 biological pathways,including cAMP signaling pathway and calcium signaling pathway.PPI analysis showed that DEGs were closely related to GABA and inflammation.RT-qPCR results showed that UA treatment increased the expression levels of GABA receptor-related gene(Gng4),GABA synthesis-related gene(Camk2a,Vgf,and Npy)and inflammation-related gene(Timp1 and Spp1)in hippocampal tissue,and decreased the expression levels of GABA synthesis-related gene(Nptx2)and cAMP-related pathway gene(Gnas).It further confirmed that UA treatment increased the expression levels of Gng4 and Camk2a on neurons and decreased the expression level of Gnas.Immunofluorescence and Western blot results showed that,compared with the SE group,the expression level of GABRG2 on primary neurons increased after UA treatment.This study enriched the transcriptome data of UA's antiepileptic effect and laid a theoretical foundation for further research on UA's antiepileptic and neuroprotective effects.