OBJECTIVETo investigate the role and signalling of microRNA(miR)-182 on regulating high glucose-induced cardiomyocyte hypertrophy.

METHODSThe candidates of miR which might potentially be involved on targeting Rac1 were predicted by applying bioinformatics analysis. The expression of all related candidates miRs was verified by real-time reverse transcription-PCR (RT-PCR) in cardiac tissues of db/db mice and db/m mice. Then the relationship between candidates miR and Rac1 was investigated with Pearson relevant analysis. Neonatal mice cardiomyocytes were cultured and divided into 2 groups: normal glucose group and high glucose group. The level of selected miR and Rac1 in two groups was detected by RT-PCR. Neonatal mice cardiomyocytes were then randomly divided into 4 groups: normal glucose group, selected microRNA mimics control group, high glucose group, high glucose plus selected miR mimics control group. The morphology of cardiomyocyte in each group was detected under light microscope. Furthermore, Rac1, β-MHC and α-SMA expressions were detected in cultured cardiomyocyte treated by high glucose for 48 h after transfecting selected miR mimics by RT-PCR and Western blot.

RESULTSA total of 6 miR candidates potentially targeting Rac1 were screened by bioinformatics, which were miR-182, miR-142-3p, miR-140, miR-101a, miR-429 and miR-200b. Among these candidates, miR-182 and miR-142-3p expression was significantly downregulated in cardiac tissues of db/db mice compared with db/m controls (P < 0.05). MiR-182 was negatively correlated with Rac1 by person analysis (r = -0.891 02). Downregulation of miR-182 and upregulation of Rac1, β-MHC, α-SMA were found in high glucose-induced cardiomyocyte. After transfection of miR-182 mimics, hypertrophic changes were significantly reduced and Rac1 as well β-MHC expression was significantly downregulated in cardiomyocyte incubated with high glucose.

CONCLUSIONMiR-182 might be involved in the regulation of high glucose-induced myocardial hypertrophy process via targeting Rac1.