Identification and Characterization of CircRNAs of Two Pig Breeds as a New Biomarker in Metabolism-Related Diseases

BACKGROUND/AIMS: CircRNAs, as miRNA sponges, participate in many important biological processes. However, it remains unclear whether circRNAs can regulate lipid metabolism. This paper aims to study the molecular mechanism of fat deposition and provide useful information for the prevention and therapy of lipid metabolism-related diseases. METHODS: CircRNA sequencing was performed to investigate the expression of circRNAs in the subcutaneous adipose tissues of Large White pig and Laiwu pig. The expression of circRNAs was further validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Furthermore, circRNA-microRNAs (miRNA)-mRNA interaction networks were constructed using bioinformatics tools. In addition, GO and KEGG enrichment analyses were performed for the target genes of circRNAs. RESULTS: In the subcutaneous adipose tissue of Laiwu pig, 70 up-regulated circRNAs and 205 down-regulated circRNAs were identified. Two circRNAs (up-regulated circRNA_26852 and down-regulated circRNA_11897), the expressions of which were confirmed by qRT-PCR, were selected for subsequent analysis. CircRNA-miRNA-mRNA interaction networks were constructed for circRNA_26852 and its target genes as well as circRNA_11897 and its target genes. GO and KEGG enrichment analyses reveal that the target genes of circRNA_26852 and circRNA_11897 are enriched in pathways related to adipocyte differentiation and lipid metabolism, as well as in disease-related pathways. CONCLUSIONS: In this study, circRNA sequencing and bioinformatics technique were used to analyze, for the first time, the expression of circRNAs in the subcutaneous adipose tissues of Large White pig and Laiwu pig. It is inferred that circRNAs might regulate adipogenic differentiation and lipid metabolism. The results provide a theoretical basis for further study on fat deposition mechanism and provide potential therapy targets for metabolism-related diseases.