BACKGROUND Buffalo milk is considered as a highly nutritious food owing to its higher contents of fatty acids (FA) and rich nutrient profile. Higher fat contents of buffalo milk make it suitable for processing to develop various healthy and nutritious products. Moreover, buffalo milk contains more unsaturated FAs (UFA) such as oleic and linolenic acid, which are important from the human health point of view owing to their desirable physiological effects. However, inadequate information is available about the chemical composition and mechanism of FA synthesis in buffalo milk. In this study, we hypothesized that expression of SCD1 gene could alter the biosynthesis of FA in epithelial cells of mammary gland and subsequently affect the FA contents in buffalo milk. We investigated the transcriptional and biological role of Stearoyl-CoA Desaturase 1 (SCD1) in the buffalo mammary epithelial cells (BMECs) during FA and triacylglycerol (TAG) synthesis. RESULTS Results revealed that unsaturated fatty acid contents were much higher in concentration in buffalo milk as compared to Holstein cow. Significant increase in the expression level of FAS, ACACA, SREBP1, PPARG, GPAT, and AGPAT genes was observed in response to altered expression of SCD1 in buffalo milk. Moreover, change in SCD1 gene in BMECs also mediated the expression of genes related to FA biosynthesis subsequently leading to alter the FA composition. Overexpression of SCD1 significantly increased the expression of genes associated with FA and TAG synthesis leading to enhance FA and unsaturated FA contents in BMECs. However, down-regulation of SCD1 exhibited opposite consequences. CONCLUSION Our study provides mechanistic insights on transcriptional regulation of SCD1 to alter FA and TAG synthesis through directly or indirectly mediating biosynthesis and metabolic pathways in BMECs. We provide preliminary findings regarding engineering of FA contents in buffalo milk through SCD1 signaling.

中文翻译：

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水牛乳中脂肪酸的生物合成和硬脂酰辅酶A去饱和酶1（SCD1）的转录调控。

背景技术水牛乳由于其脂肪酸（FA）含量较高和营养成分丰富而被认为是高营养食品。水牛乳中较高的脂肪含量使其适合加工开发各种健康和营养的产品。此外，水牛乳含有更多的不饱和脂肪酸（UFA），例如油酸和亚麻酸，由于其理想的生理作用，它们从人类健康的角度来看很重要。但是，关于水牛乳中FA的化学组成和合成机理的信息不足。在这项研究中，我们假设SCD1基因的表达可能会改变乳腺上皮细胞中FA的生物合成，进而影响水牛乳中FA的含量。我们调查了FA和三酰基甘油（TAG）合成过程中水牛乳腺上皮细胞（BMECs）中的硬脂酰辅酶A去饱和酶1（SCD1）的转录和生物学作用。结果结果表明，与荷斯坦奶牛相比，水牛牛奶中的不饱和脂肪酸含量要高得多。观察到水牛乳中SCD1表达的改变，FAS，ACACA，SREBP1，PPARG，GPAT和AGPAT基因的表达水平显着增加。而且，BMEC中SCD1基因的改变也介导了与FA生物合成有关的基因的表达，随后导致FA组成的改变。SCD1的过表达显着增加了与FA和TAG合成相关的基因的表达，从而增强了BMEC中的FA和不饱和FA含量。然而，SCD1的下调表现出相反的结果。结论我们的研究为SCD1的转录调控通过直接或间接介导BMECs的生物合成和代谢途径改变FA和TAG合成提供了机械学见解。我们通过SCD1信号传导提供有关水牛乳中FA含量工程化的初步发现。