Differential Regulatory Roles of MicroRNAs\nin Porcine Intramuscular and Subcutaneous Adipocytes

The\ndeposition of\nintramuscular (IM)\nand subcutaneous (SC) fat is an important trait influencing pork quality.\nUnderstanding the genetic differences between these two types of adipose\ntissues is consequently of great importance for pig breeding. Here,\nwe established primary cultures of IM and SC adipocytes from Jiaxing\nblack pigs. The microRNA (miRNA) expression profiles of the two types\nof adipocytes were obtained by RNA-seq. A total of 741 miRNAs were\nidentified in IM and SC adipocytes, including 155 significant differentially\nexpressed (SDE) miRNAs. According to gene ontology and Kyoto Encyclopedia\nof Genes analysis, the target genes of the SDE miRNAs were enriched\nin categories and pathways related to transcriptional regulation,\nfatty acid biosynthesis, as well as the MAPK and PI3K/Akt pathways.\nNotably, miR-206 expression was 36-fold higher in IM adipocytes than\nin SC adipocytes. The overexpression of miR-206 in IM and SC adipocytes\ndecreased cell proliferation and triglyceride accumulation. Luciferase\nactivity assays and quantitative polymerase chain reaction confirmed\nthat miR-206 regulates adipocyte proliferation by targeting STARD7\nand inhibits adipogenesis by repressing Krüppel-like factor\n4 (KLF4) expression. Accordingly, the effect of miR-206 mimics was\nattenuated by the overexpression of KLF4 in adipocytes. Taken together,\nwe identified the expression profiles of miRNAs in adipocytes, which\nrevealed that miR-206 acts as a suppressor of adipogenesis.