miR-140-5p aggravates hypoxia-induced cell injury via regulating MLK3 in H9c2 cells

• Published in: Biomedicine & pharmacotherapy Vol. 103; pp. 1652 - 1657
• Main Authors: Xing, Bing, Li, Qiao-Ju, Li, Hu, Chen, Sha-Sha, Cui, Zhi-Yuan, Ma, Jie, Zhang, Zai-Wei
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.07.2018
• Subjects: Animals; Cell Hypoxia - genetics; Cell Line; Down-Regulation - genetics; Gene Expression Regulation; Hypoxia; MAP Kinase Kinase Kinases - genetics; MAP Kinase Kinase Kinases - metabolism; MAP Kinase Signaling System; MicroRNAs - genetics; MicroRNAs - metabolism; miR-140-5p; Mitogen-Activated Protein Kinase Kinase Kinase 11; MLK3; Myocardial infarction (MI); Myocytes, Cardiac - enzymology; Myocytes, Cardiac - metabolism; Myocytes, Cardiac - pathology; p38 Mitogen-Activated Protein Kinases - metabolism; p38MAPK and JNK pathways; Rats; Transfection; Up-Regulation - genetics; p38MAPK and JNK pathways; Hypoxia; miR-140-5p; MLK3; Myocardial infarction (MI)
• ISSN: 0753-3322; 1950-6007
• DOI: 10.1016/j.biopha.2018.04.062

[Display omitted] •miR-140-5p enhances cell injury in hypoxia-injured H9c2 cells.•miR-140-5p activates the p38MAPK and JNK pathways.•MLK3 is positively regulated by miR-140-5p expression.•MLK3 overexpression blocks the protective effect of miR-140-5p inhibition. Myocardial infarction (MI) is an important cause of cardiovascular disease. microRNAs (miRNAs) have been indicated as pivotal regulators in the physiological and pathological processes of heart diseases. The purpose of this study was to investigate the role of miR-140-5p in hypoxia-induced cell injury in H9c2 cells and its underlying mechanism. H9c2 cells were subjected to hypoxia, before which the expression levels of miR-140-5p and MLK3 were overexpressed or knocked down through transient transfection. The efficiency of transfection was verified by qRT-PCR and Western blotting. Cell viability, apoptotic cell rate, and the expression changes of apoptosis-related proteins were determined by trypan blue exclusion, flow cytometry, and Western blotting, respectively. Furthermore, Western blotting was performed to assess the expression levels of core factors related with p38MAPK and JNK signaling pathways. As a result, hypoxia significantly reduced cell viability and increased cell apoptosis in H9c2 cells. miR-140-5p inhibition attenuated cell injury induced by hypoxia in H9c2 cells, while miR-140-5p overexpression expedited the cell injury, as evidenced by the decreased cell viability and enhanced cell apoptosis. Moreover, miR-140-5p promoted the activation of p38MAPK and JNK pathways. miR-140-5p positively modulated the expression of MLK3. ML3 overexpression reversed the regulatory effects of miR-140-5p inhibition on hypoxia-injured H9c2 cells. In conclusion, this study demonstrated that miR-140-5p aggravated hypoxia-induced cell injury partially through up-regulation of MLK3.