Wang Zhixia, Fu Haixin, Zhang Na
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, Heilongjiang, China.
In Vitro Cell Dev Biol Anim. 2025 Jan;61(1):24-35. doi: 10.1007/s11626-024-00974-4. Epub 2024 Sep 24.
Acetate can promote milk fat synthesis in dairy cow mammary epithelial cells (BMECs). In this study, gene function analysis was used to explore the role of Ras family secretion-related GTP binding protein 1B (SAR1B) in milk fat synthesis of BMECs and its role and molecular mechanism in acetate-promoted milk fat synthesis. We found that the synthesis of lipid droplets and triglycerides was inhibited, and the expression levels of key genes and proteins in milk fat synthesis such as FASN and ACC were decreased in SAR1B knockout, which was reversed by overexpression of SAR1B. Addition of sodium acetate in BMECs can promote the expression of SAR1B, and SAR1B plays an important role in the synthesis of milk fat promoted by sodium acetate. We further investigated the underlying mechanism of SAR1B upregulation by sodium acetate, and found that sodium acetate could affect SAR1B expression through the positive regulation of SAR1B gene promoter activity by C/EBPβ and PPARγ. In conclusion, the results suggest that SAR1B can promote milk fat synthesis in BMECs, while C/EBPβ and PPARγ play important roles in sodium acetate to promote the expression of SAR1B.
乙酸盐可促进奶牛乳腺上皮细胞（BMECs）中的乳脂肪合成。在本研究中，采用基因功能分析来探究Ras家族分泌相关GTP结合蛋白1B（SAR1B）在BMECs乳脂肪合成中的作用及其在乙酸盐促进乳脂肪合成中的作用和分子机制。我们发现，在敲除SAR1B后，脂滴和甘油三酯的合成受到抑制，乳脂肪合成中的关键基因和蛋白如FASN和ACC的表达水平降低，而SAR1B的过表达可逆转这种情况。在BMECs中添加乙酸钠可促进SAR1B的表达，且SAR1B在乙酸钠促进的乳脂肪合成中起重要作用。我们进一步研究了乙酸钠上调SAR1B的潜在机制，发现乙酸钠可通过C/EBPβ和PPARγ对SAR1B基因启动子活性的正向调节来影响SAR1B的表达。总之，结果表明SAR1B可促进BMECs中的乳脂肪合成，而C/EBPβ和PPARγ在乙酸钠促进SAR1B表达中起重要作用。
