College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, P. R. China.
College of Agriculture and Animal Husbandry, Qinghai University, No.251 Ningda Road, Xining, Qinghai 810016, P. R. China.
J Agric Food Chem. 2020 Aug 12;68(32):8589-8601. doi: 10.1021/acs.jafc.0c03917. Epub 2020 Jul 31.
Fatty acid composition plays a key role in regulating flavor and quality of milk. Therefore, in order to improve milk quality, it is particularly important to investigate regulatory mechanisms of milk fatty acid metabolism. Circular RNAs (circRNAs) regulate expression genes associated with several biological processes including fatty acid metabolism. In this study, high-throughput sequencing was used to detect differentially expressed genes in bovine mammary tissue at early lactation and peak lactation. Circ09863 profiles were influenced by the lactation stage. Functional studies in bovine mammary epithelial cells (BMECs) revealed that circ09863 promotes triglyceride (TAG) synthesis together with increased content of unsaturated fatty acids (C16:1 and C18:1). These results suggested that circ09863 is partly responsible for modulating fatty acid metabolism. Additionally, software prediction identified a miR-27a-3p binding site in the circ09863 sequence. Overexpression of miR-27a-3p in BMECs led to decreased TAG synthesis. However, overexpression of circ09863 (pcDNA-circ09863) in BMECs significantly reduced expression of miR-27a-3p and enhanced gene expression of fatty acid synthase (), a target of miR-27a-3p. Overall, data suggest that circ09863 relieves the inhibitory effect of miR-27a-3p on expression by binding miR-27a-3p and subsequently regulating TAG synthesis and fatty acid composition. Together, these mechanisms provide new research avenues and theoretical bases to improve milk quality.
脂肪酸组成在调节牛奶风味和质量方面起着关键作用。因此，为了提高牛奶质量，研究调节乳脂代谢的调控机制尤为重要。环状 RNA（circRNA）调控与脂肪酸代谢等多种生物学过程相关的基因表达。在本研究中，采用高通量测序技术检测了早期泌乳和泌乳高峰期牛乳腺组织中的差异表达基因。circ09863 的表达谱受泌乳阶段的影响。在牛乳腺上皮细胞（BMECs）中的功能研究表明，circ09863 与不饱和脂肪酸（C16:1 和 C18:1）含量增加共同促进甘油三酯（TAG）合成。这些结果表明，circ09863 部分负责调节脂肪酸代谢。此外，软件预测发现 circ09863 序列中存在 miR-27a-3p 的结合位点。在 BMECs 中转染 miR-27a-3p 过表达会导致 TAG 合成减少。然而，在 BMECs 中转染 circ09863（pcDNA-circ09863）会显著降低 miR-27a-3p 的表达并增强脂肪酸合成酶（）的基因表达，而 miR-27a-3p 是其靶基因。总体而言，数据表明 circ09863 通过结合 miR-27a-3p 缓解了 miR-27a-3p 对表达的抑制作用，从而调节 TAG 合成和脂肪酸组成。这些机制为提高牛奶质量提供了新的研究途径和理论基础。
