Chen Zhi, Luo Jun, Sun Shuang, Cao Duoyao, Shi Huaiping, Loor Juan J
a Shaanxi Key Laboratory of Molecular Biology for Agriculture , College of Animal Science and Technology, Northwest A&F University , Yangling , Shaanxi , P.R. China.
b Mammalian Nutrition Physiology Genomics, Department of Animal Sciences and Division of Nutritional Sciences , University of Illinois , Urbana , IL , USA.
RNA Biol. 2017 Mar 4;14(3):326-338. doi: 10.1080/15476286.2016.1276149. Epub 2017 Jan 17.
MicroRNA (miRNA) are a class of '18-25' nt RNA molecules which regulate gene expression and play an important role in several biologic processes including fatty acid metabolism. Here we used S-Poly (T) and high-throughput sequencing to evaluate the expression of miRNA and mRNA during early-lactation and in the non-lactating ("dry") period in goat mammary gland tissue. Results indicated that miR-148a, miR-17-5p, PPARGC1A and PPARA are highly expressed in the goat mammary gland in early-lactation and non-lactating periods. Utilizing a Luciferase reporter assay and Western Blot, PPARA, an important regulator of fatty acid oxidation, and PGC1a (PPARGC1A), a major regulator of fat metabolism, were demonstrated to be targets of miR-148a and miR-17-5p in goat mammary epithelial cells (GMECs). It was also revealed that miR-148a expression can regulate PPARA, and miR-17-5p represses PPARGC1A in GMECs. Furthermore, the overexpression of miR-148a and miR-17-5p promoted triacylglycerol (TAG) synthesis while the knockdown of miR-148a and miR-17-5p impaired TAG synthesis in GMEC. These findings underscore the importance of miR-148a and miR-17-5p as key components in the regulation of TAG synthesis. In addition, miR-148a cooperates with miR-17-5p to regulate fatty acid metabolism by repressing PPARGC1A and PPARA in GMECs. Further studies on the functional role of miRNAs in lipid metabolism of ruminant mammary cells seem warranted.
微小RNA（miRNA）是一类长度为18 - 25个核苷酸的RNA分子，其可调节基因表达，并在包括脂肪酸代谢在内的多个生物学过程中发挥重要作用。在此，我们运用S - Poly（T）和高通量测序技术，评估了山羊乳腺组织在泌乳早期和非泌乳（“干奶期”）阶段miRNA和mRNA的表达情况。结果表明，miR - 148a、miR - 17 - 5p、PPARGC1A和PPARA在山羊乳腺的泌乳早期和非泌乳期均高表达。通过荧光素酶报告基因检测和蛋白质免疫印迹法，证实脂肪酸氧化的重要调节因子PPARA以及脂肪代谢的主要调节因子PGC1a（PPARGC1A）是山羊乳腺上皮细胞（GMECs）中miR - 148a和miR - 17 - 5p的靶标。研究还发现，在GMECs中miR - 148a的表达可调节PPARA，而miR - 17 - 5p可抑制PPARGC1A。此外，miR - 148a和miR - 17 - 5p的过表达促进了甘油三酯（TAG）的合成，而敲低miR - 148a和miR - 17 - 5p则损害了GMEC中TAG的合成。这些发现强调了miR - 148a和miR - 17 - 5p作为TAG合成调控关键成分的重要性。此外，miR - 148a与miR - 17 - 5p协同作用，通过抑制GMECs中的PPARGC1A和PPARA来调节脂肪酸代谢。对反刍动物乳腺细胞脂质代谢中miRNA功能作用的进一步研究似乎很有必要。
