miRNAs play an important role in the processes of cell differentiation, biological development, and physiology. Here we investigated the molecular mechanisms regulating milk secretion and quality in dairy cows via transcriptome analyses of mammary gland tissues from dairy cows during the high-protein/high-fat, low-protein/low-fat or dry periods. To characterize the important roles of miRNAs and mRNAs in milk quality and to elucidate their regulatory networks in relation to milk secretion and quality, an integrated analysis was performed. A total of 25 core miRNAs were found to be differentially expressed (DE) during lactation compared to non-lactation, and these miRNAs were involved in epithelial cell terminal differentiation and mammary gland development. In addition, comprehensive analysis of mRNA and miRNA expression between high-protein/high-fat group and low-protein/low-fat groups indicated that, 38 miRNAs and 944 mRNAs were differentially expressed between them. Furthermore, 38 DE miRNAs putatively negatively regulated 253 DE mRNAs. The putative genes (253 DE mRNAs) were enriched in lipid biosynthetic process and amino acid transmembrane transporter activity. Moreover, putative DE genes were significantly enriched in fatty acid (FA) metabolism, biosynthesis of amino acids, synthesis and degradation of ketone bodies and biosynthesis of unsaturated FAs. Our results suggest that DE miRNAs might play roles as regulators of milk quality and milk secretion during mammary gland differentiation.

中文翻译：

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比较转录组分析以研究miRNA在牛奶蛋白/脂肪质量中的潜在作用。

miRNA在细胞分化，生物学发展和生理学过程中起着重要作用。在这里，我们通过对高蛋白/高脂，低蛋白/低脂或干燥期奶牛乳腺组织进行转录组分析，研究了调节奶牛乳汁分泌和质量的分子机制。为了表征miRNA和mRNA在牛奶质量中的重要作用并阐明其与牛奶分泌和质量相关的调节网络，进行了综合分析。与非哺乳期相比，共有25个核心miRNA在哺乳期被差异表达（DE），并且这些miRNA参与上皮细胞末端分化和乳腺发育。此外，综合分析高蛋白/高脂组和低蛋白/低脂组之间的mRNA和miRNA表达，发现它们之间有38个miRNA和944个mRNA差异表达。此外，38个DE miRNA可能负调控253个DE mRNA。假定的基因（253 DE mRNAs）丰富了脂质的生物合成过程和氨基酸跨膜转运蛋白的活性。而且，推定的DE基因在脂肪酸（FA）代谢，氨基酸的生物合成，酮体的合成和降解以及不饱和FA的生物合成中显着富集。我们的结果表明，DE miRNA可能在乳腺分化过程中充当牛奶质量和牛奶分泌的调节剂。它们之间38个miRNA和944个mRNA差异表达。此外，38个DE miRNA可能负调控253个DE mRNA。假定的基因（253 DE mRNAs）丰富了脂质的生物合成过程和氨基酸跨膜转运蛋白的活性。而且，推定的DE基因在脂肪酸（FA）代谢，氨基酸的生物合成，酮体的合成和降解以及不饱和FA的生物合成中显着富集。我们的结果表明，DE miRNA可能在乳腺分化过程中充当牛奶质量和牛奶分泌的调节剂。它们之间38个miRNA和944个mRNA差异表达。此外，38个DE miRNA可能负调控253个DE mRNA。假定的基因（253 DE mRNAs）丰富了脂质的生物合成过程和氨基酸跨膜转运蛋白的活性。而且，推定的DE基因在脂肪酸（FA）代谢，氨基酸的生物合成，酮体的合成和降解以及不饱和FA的生物合成中显着富集。我们的结果表明，DE miRNA可能在乳腺分化过程中充当牛奶质量和牛奶分泌的调节剂。推定的DE基因在脂肪酸（FA）代谢，氨基酸的生物合成，酮体的合成和降解以及不饱和FA的生物合成中显着丰富。我们的结果表明，DE miRNA可能在乳腺分化过程中充当牛奶质量和牛奶分泌的调节剂。推定的DE基因在脂肪酸（FA）代谢，氨基酸的生物合成，酮体的合成和降解以及不饱和FA的生物合成中显着丰富。我们的结果表明，DE miRNA可能在乳腺分化过程中充当牛奶质量和牛奶分泌的调节剂。