Knockout of butyrophilin subfamily 1 member A1(BTN1A1) alters lipid droplet formation and phospholipid composition in bovine mammary epithelial cells  

作　　者：Liqiang Han Menglu Zhang Zhiyang Xing Danielle N.Coleman Yusheng Liang Juan J.Loor Guoyu Yang 

机构地区：[1]College of Animal Science and Veterinary Medicine,Henan Agricultural University,Zhengzhou 450002,PR China [2]Department of Animal Sciences and Division of Nutritional Sciences,University of Illinois,Urbana,Illinois 61801,USA.

出　　处：《Journal of Animal Science and Biotechnology》2020年第4期975-985,共11页畜牧与生物技术杂志（英文版）

基　　金：supported by the National Natural Science Foundation of China (U1904116);Special Funds for Modern Agricultural Industry Technology System (CARS-37);National Key Research and Development Program of China (Beijing, China;2016YFD0500503)。

摘　　要：Background: Milk lipids originate from cytoplasmic lipid droplets(LD) that are synthesized and secreted from mammary epithelial cells by a unique membrane-envelopment process. Butyrophilin 1 A1(BTN1 A1) is one of the membrane proteins that surrounds LD, but its role in bovine mammary lipid droplet synthesis and secretion is not well known.Methods: The objective was to knockout BTN1 A1 in bovine mammary epithelial cells(BMEC) via the CRISPR/Cas9 system and evaluate LD formation, abundance of lipogenic enzymes, and content of cell membrane phospholipid(PL) species. Average LD diameter was determined via Oil Red O staining, and profiling of cell membrane phospholipid species via liquid chromatography-tandem mass spectrometry(LC-MS/MS).Results: Lentivirus-mediated infection of the Cas9/sg RNA expression vector into BMEC resulted in production of a homozygous clone BTN1 A1^((-/-)). The LD size and content decreased following BTN1 A1 gene knockout. The m RNA abundance of fatty acid synthase(FASN) and peroxisome proliferator-activated receptor-gamma(PPARG) was downregulated in the BTN1 A1^((-/-))clone. Subcellular analyses indicated that BTN1 A1 and LD were co-localized in the cytoplasm. BTN1 A1 gene knockout increased the percentage of phosphatidylethanolamine(PE) and decreased phosphatidylcholine(PC), which resulted in a lower PC/PE ratio.Conclusions: Results suggest that BTN1 A1 plays an important role in regulating LD synthesis via a mechanism involving membrane phospholipid composition.

关 键 词：Lipid droplet Mammary epithelial cell Milk fat globule PHOSPHOLIPID 

分 类 号：S823[农业科学—畜牧学]