Wang Jie, Bian Yanjie, Wang Zhuoran, Li Dan, Wang Chunmei, Li Qingzhang, Gao Xuejun
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang, China.
PLoS One. 2014 Jul 2;9(7):e101358. doi: 10.1371/journal.pone.0101358. eCollection 2014.
MicroRNAs (miRNAs) are a class of small non-coding, endogenous regulatory RNAs that function by controlling gene expression at the post-transcriptional level. Using small RNA sequencing and qRT-PCR techniques, we found that the expression of miR-152 was significantly increased during lactation in the mammary glands of dairy cows producing high quality milk compared with that in cows producing low quality milk. Furthermore, DNA methyltransferase 1 (DNMT1), which is a target of miR-152, was inversely correlated with the expression levels of miR-152 in the mammary glands of dairy cows. Dairy cow mammary epithelial cells (DCMECs) were used as in vitro cell models to study the function of miR-152. The forced expression of miR-152 in DCMECs resulted in a marked reduction of DNMT1 at both mRNA and protein levels. This in turn led to a decrease in global DNA methylation and increased the expression of two lactation-related genes, serine/threonine protein kinase Akt (Akt) and peroxisome proliferator-activated receptor gamma (Pparγ). In contrast, inhibition of miR-152 showed the opposite results. By using an electronic Coulter counter (CASY-TT) and flow cytometer, we discovered that miR-152 enhanced the viability and multiplication capacity of DCMECs. In conclusion, miR-152 plays an important role in the development and lactation processes in the mammary glands of dairy cows. Our data provide insights into dairy cow mammary gland development and lactation.
微小RNA（miRNA）是一类小的非编码内源性调节RNA，其通过在转录后水平控制基因表达发挥作用。利用小RNA测序和qRT-PCR技术，我们发现与产低质量牛奶的奶牛相比，产高质量牛奶的奶牛乳腺中miR-152的表达在泌乳期间显著增加。此外，作为miR-152靶标的DNA甲基转移酶1（DNMT1）与奶牛乳腺中miR-152的表达水平呈负相关。奶牛乳腺上皮细胞（DCMECs）被用作体外细胞模型来研究miR-152的功能。在DCMECs中强制表达miR-152导致DNMT1在mRNA和蛋白质水平均显著降低。这进而导致整体DNA甲基化减少，并增加了两个与泌乳相关的基因丝氨酸/苏氨酸蛋白激酶Akt（Akt）和过氧化物酶体增殖物激活受体γ（Pparγ）的表达。相反，抑制miR-152则产生相反的结果。通过使用电子库尔特计数器（CASY-TT）和流式细胞仪，我们发现miR-152增强了DCMECs的活力和增殖能力。总之，miR-152在奶牛乳腺的发育和泌乳过程中发挥重要作用。我们的数据为奶牛乳腺发育和泌乳提供了见解。
