Comparative analysis of gene expression profiles in differentiated subcutaneous adipocytes between Jiaxing Black and Large White pigs.

BACKGROUND

Chinese domestic pig breeds are reputed for pork quality, but their low ratio of lean-to-fat carcass weight decreases production efficiency. A better understanding of the genetic regulation network of subcutaneous fat tissue is necessary for the rational selection of Chinese domestic pig breeds. In the present study, subcutaneous adipocytes were isolated from Jiaxing Black pigs a Chinese indigenous pig breed with redundant subcutaneous fat deposition and Large White pigs a lean-type pig breed with relatively low subcutaneous fat deposition. The expression profiles of mRNAs and lncRNAs were compared by RNA-seq analysis to identify biomarkers correlated with the differences of subcutaneous fat deposition between the two breeds.

RESULTS

A total of 1058 differentially expressed genes and 221 differentially expressed lncRNAs were identified in subcutaneous adipocytes between Jiaxing Black and Large White pigs, which included 275 up-regulated mRNAs, 783 down-regulated mRNAs, 118 up-regulated lncRNAs and 103 down-regulated lncRNAs. Gene Ontology and KEGG pathway enrichment analyses revealed that the differentially expressed genes and differentially expressed lncRNAs were mainly involved in the immune response, cell fate determination, PI3K-Akt signaling pathway and MAPK signaling pathway, which are known to be related to adipogenesis and lipid metabolism. The expression levels of differentially expressed genes and differentially expressed lncRNAs according to the RNA-seq data were verified by quantitative PCR, which showed 81.8% consistency. The differences in MAPK pathway activity between Jiaxing Black and Large White pigs was confirmed by western blot analysis, which revealed elevated p38 phosphorylation in Jiaxing Black pigs.

CONCLUSIONS

This study offers a detailed characterization of mRNAs and lncRNAs in fat- and lean-type pig breeds. The activity of the MAPK signaling pathway was found to be associated with subcutaneous adipogenesis. These results provide new targets for further investigation of the molecular mechanisms regulating subcutaneous fat deposition in pigs.