MicroRNA (miRNA) has been proved to play a key role in lipid metabolism. In our previous study, miR-125b was validated to be differentially expressed in preadipocytes and adipocytes, which was also proved to involve in lipid metabolism. To explore the comprehensive targets of miR-125b in adipocytes, isobaric tag for relative and absolute quantitation (iTRAQ) analysis was performed to obtain differentially expressed proteins in adipocytes comparing negative control (NC) and miR-125b mimic, combining with digital gene expression (DGE) profiling of mRNA incorporated into RNA-induced silencing complex (RISC) pulled down by biotinylated miR-125b mimic and targets prediction of miR-125b by three algorithms, acyl-CoA dehydrogenase short chain (ACADS) and mitochondrial trans-2-enoyl-CoA reductase (MECR) were screened out as miR-125b direct targets. Luciferase reporter assay further validated that miR-125b mimic significantly inhibited the luciferase activity by targeting wild type (WT) 3′-UTR compared with NC. qPCR analysis of ACADS and MECR mRNA from adipose tissues of miR-125b knockout (KO) mice further confirmed the inhibition of miR-125b on ACADS and MECR expressions. Here we report miR-125b play a vital role in maintaining homeostasis of fatty acid metabolism by targeting key enzyme ACADS and MECR in the process of fatty acid elongation and degradation.

MicroRNA（miRNA）已被证明在脂质代谢中起关键作用。在我们之前的研究中，证实miR-125b在前脂肪细胞和脂肪细胞中差异表达，这也被证明参与脂质代谢。为了探索miR-125b在脂肪细胞中的综合靶标，进行了相对和绝对定量（iTRAQ）分析的同量异位标记，以比较阴性对照（NC）和miR-125b模拟物并结合数字基因表达来获得脂肪细胞中差异表达的蛋白质（ DGE）分析被生物素化的miR-125b模拟物下拉的RNA诱导沉默复合物（RISC）中掺入的mRNA，并通过酰基辅酶A脱氢酶短链（ACADS）和线粒体反式2-烯酰基三种算法靶向miR-125b的预测筛选出CoA还原酶（MECR）作为miR-125b直接靶标。荧光素酶报告基因测定进一步证实，与NC相比，miR-125b模拟物通过靶向野生型（WT）3'-UTR显着抑制了荧光素酶活性。来自miR-125b敲除（KO）小鼠脂肪组织的ACADS和MECR mRNA的qPCR分析进一步证实了miR-125b对ACADS和MECR表达的抑制作用。在这里，我们报告miR-125b通过在脂肪酸延长和降解过程中靶向关键酶ACADS和MECR，在维持脂肪酸代谢的稳态中起着至关重要的作用。