Inhibition of miR-217 Protects Against Myocardial Ischemia-Reperfusion Injury Through Inactivating NF-κB and MAPK Pathways

Purpose Recent studies have demonstrated that miRNAs play a vital role in regulating myocardial ischemia/reperfusion injury (MIRI). MiR-217 has been proven to be implicated in cardiac diseases such as chronic heart failure and cardiac myxoma. However, the role of miR-217 in MIRI is not clear. Methods A mouse MIRI model was established and the myocardial infarct size was evaluated by TTC staining. The expression level of miR-217 in I/R group was determined by real-time polymerase chain reaction. Subsequently, MIRI mice and H9C2 cells were administrated with miR-217 inhibitor in vivo and in vitro, respectively. The levels of TNF-alpha and IL-6 were measured by commercially available ELISA kits. Blood and cell samples were collected for the measurement of lactate dehydrogenase (LDH) level and caspase-3 activity. Cell viability was assessed with the CCK-8 assay. We then explored the detailed molecular mechanisms by TargetScan 7.1 database and further studies were performed to prove the prediction by dual-luciferase reporter assay. Results Larger stainless infarct areas were observed in the MIRI group, accompanied by inceased serum LDH activity, indicating the mouse MIRI model was successfully established. MiR-217 was up-regulated in MIRI mice and hypoxia/reoxygenation-treated H9C2 cells. MiR-217 knockdown alleviated the MIRI in MIRI mouse model, and also attenuated the myocardial hypoxia/reoxygenation injury in H9C2 cells. Moreover, dual specificity protein phosphatase 14 (DUSP14) was proved to be a target of miR-217. Besides, further study indicated that inhibition of miR-217 protected against MIRI through inactivating NF-kappa B and MAPK pathways via targeting DUSP14. Conclusions MiR-217 inhibition protected against MIRI through inactivating NF-kappa B and MAPK pathways by targeting DUSP14. This study may provide valuable diagnostic and factors and therapeutic agents for MIRI.