[Identification and bioinformatics analysis of differentially expressed microRNAs in mice liver tissues with a high fat diet-induced insulin resistance]

To identify the expression levels of miR-1897-3p, miR-690 and miR-7a-5p in mice liver tissues with a high fat diet-induced insulin resistance using a stem-loop reverse transcriptional real-time fluorescence quantitative PCR( RT-q PCR)method, and predict microRNAs( miRNAs)-regulated target genes and their functions to investigate the relationship between insulin resistance and differentially expressed miRNAs.

The total of 30 liver tissue samples were obtained from 15 normal control mice and 15 test mice with a high fat diet-induced insulin resistance. The stemloop reverse transcriptional primers and the primers of real-time PCR were designed to establish a RT-q PCR method, and then the expression levels of miR-1897-3p, miR-690 and miR-7a-5p of 30 liver tissue samples were detected and analyzed. Using bioinformatics methods, the target genes of differentially expressed miRNAs were predicted, and then enriched gene ontology( GO), related signal pathways and target gene protein-target gene protein interactions were analyzed, respectively.

Compared with control group, the expression levels of miR-1897-3p, miR-690 and miR-7a-5p detected by RT-q PCR in the group with a high-fat diet-induced insulin resistance were significantly decreased( P < 0. 05), which exhibited the similar pattern of down regulation to the previous microarray results. Bioinformatics analysis results showed that a total of 16 target genes were regulated by two differentially expressed miRNAs. Among of the 16 target gene protein, 8 proteins had interactions with ≥4 proteins. Rac1, Rhoa, Prkcz, Tgfbr2, Itch and Ube2d3 protein were located in the central node of the network, and they were associated or cross-linking with insulin signaling pathway.

miR-1897-3p, miR-690 and miR-7a-5p in liver tissues may be involved in the physiopathologic process of insulin resistance, which may be affect the normal insulin signaling pathway cascade by regulating the expression of target genes.