基于转录组测序对圆口铜鱼脂肪肝表型的分析

Analysis of fatty liver phenotype in juvenile largemouth bronze gudgeon (Coreius guichenoti) based on transcriptome sequencing

为研究圆口铜鱼(Coreius guichenoti)幼鱼脂肪肝的形成原因,本试验对无明显异常肝脏和脂肪肝进行比较转录组分析。转录组共获得50665条Unigene,大小主要分布在300~1000 bp,占比达到65.42%。与Nr、GO、KEGG、Pfam、COG和Swiss-Prot数据库进行功能注释,筛选得到有2438个差异表达基因,其中上调1195个,下调1243个。KEGG代谢通路分析发现,脂代谢相关的PPAR信号通路、甘油酯代谢、脂肪酸生物合成和类固醇生物合成通路与脂肪肝的形成密切相关。对脂代谢相关的差异基因进行分析,发现脂合成相关基因GPAT3、LPIN1、PLPP1、FASN、ACC1和ACPM显著上调,而脂解相关基因PNPLA2、MGLL、LPL、DGKB和ACSL显著下调;并且脂肪肝组ACC和FASN酶活水平显著上升,而脂解相关酶活HSL和CPT1显著下调。因此,肝脏脂合成的增加、脂解的降低导致肝脏脂肪蓄积和脂代谢的紊乱可能是圆口铜鱼幼鱼脂肪肝形成的主要原因,该结果在一定程度上解释了圆口铜鱼幼鱼脂肪肝形成的原因,也为后续研究其代谢调控及肝脏疾病预防等方面提供理论基础。

In order to investigate the cause of fatty liver in juvenile largemouth bronze gudgeon(Coreius guichenoti),RNA-Seq technology was conducted on the phenotypes of no abnormality liver and fatty liver.A total of 50665 Unigene was obtained by transcriptome splicing and assembly.The length of Unigene was mainly 300~1000 bp,accounting for 65.42%of the total Unigene.In comparison with Nr,GO,KEGG,Pfam,COG and Swiss-Prot databases,2438 differentially expressed genes were identified,of which 1195 were upregulated and 1243 were downregulated.KEGG metabolic pathway analysis revealed that fatty liver formation was closely linked to lipid metabolism,in particular the PPAR signaling pathway,glycerolipid metabolism,fatty acid biosynthesis,and steroid biosynthesis pathways.Further analysis of differentially expressed genes revealed that lipid synthesis genes,such as GPAT3,LPIN1,PLPP1,FASN,ACC1 and ACPM were significantly upregulated,while lipolysis related genes,such as PNPLA2,MGLL,LPL,DGKB and ACSL were significantly downregulated.Meanwhile,enzyme activities of ACC and FASN in the fatty liver group were significantly increased,while HSL and CPT1 were significantly decreased.Therefore,fatty liver accumulation was mainly caused by increased lipid synthesis and decreased lipolysis,resulting in fatty liver.To a certain extent,the results provided a theoretical basis for future study on metabolic regulation and liver disease in juvenile largemouth bronze gudgeon.