Regulative Effect of microRNA let-7c on Myotrophin Gene Expression in Rat’s H9c2 Cardiac Myocytes / 中国循环杂志

ABSTRACT

Objective: To explore weather microRNA let-7c (miR-let-7c) could regulate myotrophin gene expression in rat’s H9c2 cardiac myocytes with possible mechanisms. Methods: Recombinant plasmid carrying 3′ untranslated region (3′-UTR) of myotrophin and miRNA precursor of let-7c was co-transfected into Hela cells to construct the luciferase reporter system in order to measure luciferase activity. Rat’s H9c2 cardiac myocytes were cultured. The let-7c gene expression was detected by Taqman probe-based real-time PCR after let-7c miRNA precursor or let-7c miRNA inhibitor transfection respectively; protein expressions of myotrophin and nuclear factor-κB (NF-κB) were examined by Western blot analysis. Results: Luciferase activity examination indicated that compared with recombinant luciferase gene expression carrier (pMIR-MTPN)+miR precursor negative control group, pMIR-MTPN+miR-let-7c miRNA precursor group showed reduced luciferase activity (59.30±9.90) % vs (98.10±15.10) %. Western blot analysis presented that compared with miR negative control group, miR-let-7c precursor group had decreased protein expressions of myotrophin (0.28±0.05) vs (0.90±0.09) and NF-κB (0.25±0.06) vs (0.75±0.07); in contrast, compared with Negative inhibitor group, miR-let-7c inhibitor group had increased protein expressions of myotrophin (1.14±0.09) vs (0.44±0.09) and NF-κB (1.09±0.05) vs (0.71±0.06), allP Conclusion: miR-let-7c could inhibit myotrophin expression via acting on its 3′-UTR domain and may also inlfuence NF-κB signaling pathway in rat’s H9c2 cardiac myocytes.