Table3_MiRNA-Seq reveals key MicroRNAs involved in fat metabolism of sheep liver.XLSX

There is a genetic difference between Hu sheep (short/fat-tailed sheep) and Tibetan sheep (short/thin-tailed sheep) in tail type, because of fat metabolism. Previous studies have mainly focused directly on sheep tail fat, which is not the main organ of fat metabolism. The function of miRNAs in sheep liver fat metabolism has not been thoroughly elucidated. In this study, miRNA-Seq was used to identify miRNAs in the liver tissue of three Hu sheep (short/fat-tailed sheep) and three Tibetan sheep (short/thin-tailed sheep) to characterize the differences in fat metabolism of sheep. In our study, Hu sheep was in a control group, we identified 11 differentially expressed miRNAs (DE miRNAs), including six up-regulated miRNAs and five down-regulated miRNAs. Miranda and RNAhybrid were used to predict the target genes of DE miRNAs, obtaining 3,404 target genes. A total of 115 and 67 GO terms as well as 54 and 5 KEGG pathways were significantly (padj < 0.05) enriched for predicted 3,109 target genes of up-regulated and 295 target genes of down-regulated miRNAs, respectively. oar-miR-432 was one of the most up-regulated miRNAs between Hu sheep and Tibetan sheep. And SIRT1 is one of the potential target genes of oar-miR-432. Furthermore, functional validation using the dual-luciferase reporter assay indicated that the up-regulated miRNA; oar-miR-432 potentially targeted sirtuin 1 (SIRT1) expression. Then, the oar-miR-432 mimic transfected into preadipocytes resulted in inhibited expression of SIRT1. This is the first time reported that the expression of SIRT1 gene was regulated by oar-miR-432 in fat metabolism of sheep liver. These results could provide a meaningful theoretical basis for studying the fat metabolism of sheep.

本研究揭示了胡羊（短尾/肥胖型羊）与藏绵羊（短尾/细尾型羊）在尾型上的遗传差异，此差异源于脂肪代谢的差异。以往研究主要直接聚焦于羊尾脂肪，然而羊尾并非脂肪代谢的主要器官。羊肝中miRNA在脂肪代谢中的功能尚未得到充分阐明。在本研究中，我们利用miRNA-Seq技术对三只胡羊（短尾/肥胖型羊）和三只藏绵羊（短尾/细尾型羊）的肝组织进行测序，以表征羊脂肪代谢的差异。在本研究设定中，胡羊作为对照组，我们鉴定出11个差异表达miRNA（DE miRNA），包括6个上调miRNA和5个下调miRNA。通过Miranda和RNAhybrid软件预测DE miRNA的目标基因，共获得3,404个目标基因。对于上调miRNA预测的3,109个目标基因和下调miRNA预测的295个目标基因，分别有115和67个GO术语以及54和5个KEGG通路在统计学上显著富集（padj < 0.05）。在胡羊与藏绵羊之间，oar-miR-432是上调miRNA中最显著的一个。SIRT1是oar-miR-432的潜在靶基因之一。此外，利用双荧光素酶报告基因检测法进行的机能验证表明，上调miRNA oar-miR-432可能靶向沉默信息调节因子1（SIRT1）的表达。随后，将oar-miR-432模拟物转染至前脂肪细胞中，导致SIRT1表达受抑制。这是首次报道SIRT1基因的表达在羊肝脂肪代谢中受到oar-miR-432的调控。这些研究结果可为研究羊的脂肪代谢提供有意义的理论依据。