Hepatic microRNAome reveals potential microRNA-mRNA pairs association with lipid metabolism in pigs

Abstract

Objective: As one of the most important metabolic organs, the liver plays vital roles in modulating the lipid metabolism. This study was to compare miRNA expression profiles of the Large White liver between two different developmental periods and to identify candidate miRNAs for lipid metabolism. Methods: Eight liver samples were collected from White Large of 70day fetus (P70) and of 70day piglets (D70) (with 4 biological repeats at each development period) to construct sRNA libraries. Then the eight prepared sRNA libraries were sequenced using Illumina nextgeneration sequencing technology on HiSeq 2500 platform. Results: As a result, we obtained 346 known and 187 novel miRNAs. Compared with the D70, 55 down and 61 upregulated miRNAs were shown to be significantly differentially expressed (DE). Gene ontology and Kyoto encyclopedia of genes and genomes enrichment analysis indicated that these DE miRNAs were mainly involved in growth, development and diverse metabolic processes. They were predicted to regulate lipid metabolism through adipocytokine signaling pathway, mitogenactivated protein kinase, AMPactivated protein kinase, cyclic adenosine monophosphate, phosphatidylinositol 3 kinase/protein kinase B, and Notch signaling pathway. The four most abundantly expressed miRNAs were miR122, miR26a and miR30a5p (miR122 only in P70), which play important roles in lipid metabolism. Integration analysis (details of mRNAs sequencing data were shown in another unpublished paper) revealed that many target genes of the DE miRNAs (miR181b, miR1455p, miR199a5p, and miR98) might be critical regulators in lipid metabolic process, including acylCoA synthetase long chain family member 4, ATPbinding casette A4, and stearylCoA desaturase. Thus, these miRNAs were the promising candidates for lipid metabolism. Conclusion: Our study provides the main differences in the Large White at miRNA level between two different developmental stages. It supplies a valuable database for the further function and mechanism elucidation of miRNAs in porcine liver development and lipid metabolism.