Abstract
MicroRNA (miRNA) regulates the expression of genes and influences a series of biological processes, including fatty acid metabolism. We screened the expression of miRNA in goat mammary glands during peak-lactation and non-lactating (“dry”) periods, and performed an in vitro study with goat mammary epithelial cells (GMEC) prior to sequencing analysis. Results illustrated that miR-30e-5p and miR-15a were highly expressed. Utilizing a luciferase reporter assay and Western blot, low-density lipoprotein receptor-related protein 6 (LRP6) and Yes associated protein 1 (YAP1) genes were demonstrated to be a target of miR-30e-5p and miR-15a in GMEC. Moreover, we demonstrated that the overexpression of miR-30e-5p and miR-15a in GMEC promoted fat metabolism while their knockdown impaired fat metabolism. These findings extend the discovery of a key role of miR-30e-5p and miR-15a in mediating adipocyte differentiation by suggesting a role in promoting milk fat synthesis. In conclusion, our findings indicate that miR-30e-5p, together with miR-15a, represses expression of LRP6 and promotes fat metabolism in GMEC. The data expanded our knowledge on the function of miRNAs in milk fat metabolism and synthesis in ruminant mammary cells.
Highlights
Goat milk contains high concentrations short-chain fatty acids and unsaturated fatty acids, which can elicit positive effects on human health [1,2,3]
Our results revealed that miR-30e-5p and miR-15a are highly-expressed in the mammary gland of goats, and in goat mammary epithelial cells (GMEC) cultured with prolactin
Some reports have showed that miRNA participates in the regulation of milk fat metabolism [28,29,30]
Summary
Goat milk contains high concentrations short-chain fatty acids and unsaturated fatty acids, which can elicit positive effects on human health [1,2,3]. MicroRNA are members of the non-coding RNA family, and are composed of 21–23 nucleotides [9,10,11] They can negatively regulate target genes via mRNA splicing and inhibiting protein translation [12,13,14,15]. Despite the vast amount of work on miRNA in non-ruminant species [21], there are few studies focused on the function and mechanisms whereby miRNA synergistically regulates the process of milk fat metabolism [22,23,24]. By working in concert with transcription factors, and promoting the expression of certain genes, Yes-associated protein (YAP) and its downstream proteins in the Hippo signaling pathway, play a crucial role in promoting cell growth and inhibiting apoptosis. Our research illustrates that miR-30e-5p and miR-15a play a significant role in the accumulation of milk fat in ruminants
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