Circ11103 Interacts with miR-128/<i>PPARGC1A</i> to Regulate Milk Fat Metabolism in Dairy Cows

The quality of milk is inseparable from its milk components, and fatty acid content is a key factor affecting the quality of milk. In this study, the miRNA and mRNA profiles of the bovine mammary gland tissue during the dry period and the peak lactation period were determined through high-throughput sequencing. In total, 72 miRNA–mRNA regulatory pathways were screened, including miR-128/PPARGC1A regulatory pathways. miR-128 can directly target PPARGC1A and inhibit its expression. In addition, the study also observed that there was a miR-128 binding site in the sequence of the circular RNA circ11103, and circ11103 significantly reduced the expression of miR-128. circ11103 upregulated the triglyceride levels in bovine mammary epithelial cells (BMECs) and increased the contents of unsaturated fatty acids. However, miR-128 decreased triglyceride and cholesterol levels in BMECs. This study aims to analyze the mechanism governing the regulatory effect of circ11103 on milk fat metabolism, which provides new insights into improving milk quality.牛乳品质与其乳成分息息相关，而脂肪酸含量是影响牛乳品质的关键因素。本研究通过高通量测序技术，测定了牛乳腺组织在干奶期与泌乳高峰期的微小RNA（microRNA, miRNA）和信使RNA（messenger RNA, mRNA）表达谱。本研究共筛选得到72条miRNA-mRNA调控通路，其中包含miR-128/PPARGC1A调控通路。miR-128可直接靶向PPARGC1A并抑制其表达。此外，本研究还发现环状RNA（circular RNA, circRNA）circ11103的序列中存在miR-128结合位点，且circ11103可显著降低miR-128的表达水平。circ11103可上调牛乳腺上皮细胞（bovine mammary epithelial cells, BMECs）中的甘油三酯水平，并提升不饱和脂肪酸含量；而miR-128则会降低BMECs内的甘油三酯与胆固醇水平。本研究旨在解析circ11103调控乳脂代谢的分子机制，为改善牛乳品质提供全新的研究视角。