Liang Meng-yao, Hou Xiao-ming, Qu Bo, Zhang Na, Li Nan, Cui Ying-jun, Li Qing-zhang, Gao Xue-jun
Key Laboratory of Agricultural Biological Functional Genes, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin, 150030, Heilongjiang Province, China.
In Vitro Cell Dev Biol Anim. 2014 Oct;50(9):865-73. doi: 10.1007/s11626-014-9780-z. Epub 2014 Jun 20.
Milk fat is the major energy component of milk, and regulation of its production relies on transcription factors sterol regulatory element-binding protein 1 (SREBP1) and peroxisome proliferator-activated receptor gamma (PPARγ). As one of the target genes of SREBP1 and PPARγ, fatty acid-binding protein 3(FABP3) is the main protein allowing for rapid diffusion and selective targeting of long-chain fatty acids toward specific organelles for metabolism. Whether FABP3 plays an important role in milk fat synthesis signaling pathway is largely unknown. In this study, we observed the effects of FABP3 overexpression and gene silencing in dairy cow mammary epithelial cells, as well as the effects of oleic acid, stearic acid, and palmitic acid on the expressions of FABP3 and lipid droplet formation, by using quantitative reverse transcriptase (qRT)-PCR, Western blotting, and fluorescent immunostaining techniques. FABP3 upregulated the expression of SREBP1 and PPARγ to increase lipid droplet accumulation. Oleic acid, stearic acid, and palmitic acid also increased lipid droplet accumulation by affecting expression of FABP3. These findings shed new insights for understanding the mechanism of FABP3 in regulating milk fat synthesis.
乳脂肪是牛奶中的主要能量成分，其合成调控依赖于转录因子固醇调节元件结合蛋白1（SREBP1）和过氧化物酶体增殖物激活受体γ（PPARγ）。作为SREBP1和PPARγ的靶基因之一，脂肪酸结合蛋白3（FABP3）是一种主要蛋白质，可使长链脂肪酸快速扩散并选择性地靶向特定细胞器进行代谢。FABP3是否在乳脂肪合成信号通路中发挥重要作用，目前尚不清楚。在本研究中，我们通过定量逆转录（qRT）-PCR、蛋白质免疫印迹和荧光免疫染色技术，观察了FABP3过表达和基因沉默对奶牛乳腺上皮细胞的影响，以及油酸、硬脂酸和棕榈酸对FABP3表达和脂滴形成的影响。FABP3上调SREBP1和PPARγ的表达，以增加脂滴积累。油酸、硬脂酸和棕榈酸也通过影响FABP3的表达增加脂滴积累。这些发现为理解FABP3调控乳脂肪合成的机制提供了新的见解。
