Yao Weiwei, Luo Jun, Tian Huibin, Niu Huimin, An Xuetong, Wang Xinpei, Zang Saige
Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang 712100, China.
Foods. 2022 Apr 29;11(9):1291. doi: 10.3390/foods11091291.
Malonyl/acetyltransferase (MAT) is a crucial functional domain of fatty acid synthase (FASN), which plays a vital role in the de novo synthesis of fatty acids in vivo. Milk fatty acids are secreted by mammary epithelial cells. Mammary epithelial cells are the units of mammary gland development and function, and it is a common model for the study of mammary gland tissue development and lactation. This study aimed to investigate the effects of MAT deletion on the synthesis of triacylglycerol and medium-chain fatty acids. The MAT domain was knocked out by CRISPR/Cas9 in the goat mammary epithelial cells (GMECs), and in MAT knockout GMECs, the mRNA level of FASN was decreased by approximately 91.19% and the protein level decreased by 51.83%. The results showed that MAT deletion downregulated the contents of triacylglycerol and medium-chain fatty acids (p < 0.05) and increased the content of acetyl-Coenzyme A (acetyl-CoA) (p < 0.001). Explicit deletion of MAT resulted in significant drop of FASN, which resulted in downregulation of LPL, GPAM, DGAT2, PLIN2, XDH, ATGL, LXRα, and PPARγ genes in GMECs (p < 0.05). Meanwhile, mRNA expression levels of ACC, FASN, DGAT2, SREBP1, and LXRα decreased following treatment with acetyl-CoA (p < 0.05). Our data reveals that FASN plays critical roles in the synthesis of medium-chain fatty acids and triacylglycerol in GMECs.
丙二酰/乙酰转移酶（MAT）是脂肪酸合酶（FASN）的一个关键功能结构域，在体内脂肪酸的从头合成中起着至关重要的作用。乳脂肪酸由乳腺上皮细胞分泌。乳腺上皮细胞是乳腺发育和功能的基本单位，是研究乳腺组织发育和泌乳的常用模型。本研究旨在探讨MAT缺失对甘油三酯和中链脂肪酸合成的影响。通过CRISPR/Cas9在山羊乳腺上皮细胞（GMECs）中敲除MAT结构域，在MAT敲除的GMECs中，FASN的mRNA水平下降了约91.19%，蛋白质水平下降了51.83%。结果表明，MAT缺失下调了甘油三酯和中链脂肪酸的含量（p<0.05），并增加了乙酰辅酶A（乙酰-CoA）的含量（p<0.001）。MAT的明确缺失导致FASN显著下降，进而导致GMECs中LPL、GPAM、DGAT2、PLIN2、XDH、ATGL、LXRα和PPARγ基因下调（p<0.05）。同时，用乙酰-CoA处理后，ACC、FASN、DGAT2、SREBP1和LXRα的mRNA表达水平下降（p<0.05）。我们的数据表明，FASN在GMECs中链脂肪酸和甘油三酯的合成中起关键作用。
