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-α 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-κB and MAPK pathways via targeting DUSP14.

Conclusions

MiR-217 inhibition protected against MIRI through inactivating NF-κB and MAPK pathways by targeting DUSP14. This study may provide valuable diagnostic and factors and therapeutic agents for MIRI.

中文翻译：

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通过抑制NF-κB和MAPK途径，抑制miR-217可防止心肌缺血再灌注损伤。

目的

最近的研究表明，miRNA在调节心肌缺血/再灌注损伤（MIRI）中起着至关重要的作用。已证明，MiR-217与心脏病有关，例如慢性心力衰竭和心脏粘液瘤。但是，miR-217在MIRI中的作用尚不清楚。

方法

建立小鼠MIRI模型，并通过TTC染色评价心肌梗塞大小。I / R组中miR-217的表达水平通过实时聚合酶链反应确定。随后，分别在体内和体外向MIRI小鼠和H9C2细胞施用miR-217抑制剂。TNF-α和IL-6的水平通过市售ELISA试剂盒测量。收集血液和细胞样品以测量乳酸脱氢酶（LDH）水平和caspase-3活性。用CCK-8测定法评估细胞活力。然后，我们通过TargetScan 7.1数据库探索了详细的分子机制，并进行了进一步的研究以通过双荧光素酶报告基因测定法证明该预测。

结果

在MIRI组中观察到更大的不锈钢梗死区域，并伴有血清LDH活性增加，表明成功建立了小鼠MIRI模型。在MIRI小鼠和缺氧/复氧治疗的H9C2细胞中，MiR-217上调。MiR-217敲低减轻了MIRI小鼠模型中的MIRI，也减轻了H9C2细胞的心肌缺氧/复氧损伤。此外，双重特异性蛋白磷酸酶14（DUSP14）被证明是miR-217的目标。此外，进一步的研究表明对miR-217的抑制作用是通过靶向DUSP14使NF-κB和MAPK通路失活而实现的，从而可以抵抗MIRI 。

结论

通过靶向DUSP14，可通过失活NF-κB和MAPK途径来抑制MIR-217抑制MIRI。这项研究可能为MIRI提供有价值的诊断和因素以及治疗药物。