MiR-423-5p inhibition alleviates cardiomyocyte apoptosis and mitochondrial dysfunction caused by hypoxia/reoxygenation through activation of the wnt/β-catenin signaling pathway via targeting MYBL2.

MicroRNA (miR) plays an integral role in cardiovascular diseases. M-iR-423-5p is aberrantly expressed in patients with myocardial infarction and heart failure. The aim of the present study was to study the roles and mechanisms of miR-423-5p in hypoxia/reoxygenation (H/R) mediated cardiomyocytes injury. H9C2 cells were transfected with negative control, miR-423-5p mimic, and inhibitor for 48 hr, followed by exposed to H/R condition. Cell apoptosis rate, caspase 3/7 activities, Bax and cleaved-caspase 3 (c-caspase 3) protein levels were assayed by flow cytometry, Caspase-Glo 3/7 Assay kit, western blot analysis, respectively. Furthermore, the mitochondrial membrane potential, adenosine triphosphate (ATP) content, reactive oxygen species (ROS) production, and Drp1 expression were also investigated. Furthermore, the dual-luciferase reporter assay was used to evaluate the relationship between miR-423-5p and Myb-related protein B (MYBL2). The roles of miR-423-5p in wnt/β-catenin were assessed by western blot analysis. The results revealed that H/R triggered miR-423-5p expression. Overexpression of miR-423-5p promoted cardiomyocyte apoptosis, enhanced the activities of caspase 3/7, upregulated the expression of Bax and c-caspase 3. miR-423-5p upregulation caused the loss of mitochondrial membrane potential and the reduction of ATP content, the augment of ROS production and Drp1 expression. However, the opposite trends were observed upon suppression of miR-423-5p. In addition, miR-423-5p could target the 3' untranslated region of MYBL2. miR-423-5p depletion led to the activation of the wnt/β-catenin signaling pathway via targeting MYBL2. Knockdown of MYBL2 was obviously reversed the roles of miR-423-5p in apoptosis and mitochondrial dysfunction. Taken together, miR-423-5p suppression reduced H/R-induced cardiomyocytes injury through activation of the wnt/β-catenin signaling pathway via targeting MYBL2 in cardiomyocytes.

Zhu X ，Lu X 《-》

MiR-26a-5p Targets WNT5A to Protect Cardiomyocytes from Injury Due to Hypoxia/Reoxygenation Through the Wnt/β-catenin Signaling Pathway.

Yan G ，Wang J ，Fang Z ，Yan S ，Zhang Y ... -  《-》

Inhibition of miR-148b ameliorates myocardial ischemia/reperfusion injury via regulation of Wnt/β-catenin signaling pathway.

Our work aims to elucidate the effect how microRNA-148b (miR-148b) participated in myocardial ischemia/reperfusion (I/R) injury via regulation of Wnt/β-catenin signaling pathway. The in vivo myocardial I/R models of SD rats and in vitro hypoxia/reoxygenation (H/R) models of H9C2 cells were established. The heart function and infarction area of rats and lactic dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA), and superoxide dismutase (SOD) levels were evaluated. Myocardial cell viability was measured using positron emission tomography combined with computer tomography and (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and the apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated nick-end labeling method and flow cytometry; quantitative reverse-transcription polymerase chain reaction and western blot were used to detect the related molecules expressions. The myocardial infarction area of rats was significantly increased with reductions in LVSP, + dp/dtmax, - dp/dtmax, LVFS%, LVEF% and standardized uptake value and elevation in left ventricular developed pressure after ischemia/reperfusion (I/R), and the LDH, CK, and MDA levels were enhanced with the decreased SOD. The apoptotic rates were higher in I/R rats and H/R H9C2 cells with upregulated miR-148b and cleaved caspase-3, but decreased Bcl-2/Bax ratio; and meanwhile, the Wnt/β-catenin pathway was inhibited. Additionally, the H/R-induced H9C2 cells also exhibited decreased cell viability. MiR-148b overexpression further aggravated I/R injury of rats, whereas inhibition of miR-148b reduced I/R and H/R injury through activation of Wnt/β-catenin pathway. In addition, Wnt-1 small interfering RNA exposure abolished the effect of miR-148b inhibitor on H/R injury of H9C2 cells. Inhibition of miR-148b improved the antioxidative ability and myocardial cell survival to suppress its apoptosis by activating Wnt/β-catenin signaling pathway, thus ameliorating the myocardial I/R injury.

Yang M ，Kong DY ，Chen JC 《-》

MiR-7a-5p Attenuates Hypoxia/Reoxygenation-Induced Cardiomyocyte Apoptosis by Targeting VDAC1.

MicroRNA-7a-5p (miR-7a-5p) is closely related to apoptosis and plays an important role in ischemia/reperfusion (I/R) injury. Whether miR-7a-5p is involved in hypoxia/reoxygenation (H/R)-induced cardiomyocyte apoptosis is unknown. Therefore, this study aims to evaluate the role of miR-7a-5p in cardiomyocyte H9C2 cells in response to H/R stimulation. The results of RT-qPCR demonstrated that the expression level of miR-7a-5p was significantly down-regulated in H/R-treated H9C2 cells. MTT assay revealed that the cell viability was notably decreased in H/R group. Flow cytometric analysis found that the ratio of apoptotic cells was increased markedly following H/R. Enforced miR-7a-5p expression increased cell viability and decreased the apoptotic rate. Western blot analysis revealed that the expressions of pro-apoptotic proteins cleaved caspase-3 and Bax were down-regulated, while the expression of anti-apoptotic protein Bcl-2 was up-regulated in H/R-treated H9C2 cells transfected with miR-7a-5p mimic. On the contrary, miR-7a-5p downexpressing promoted apoptosis in H/R-treated H9C2 cells. Furthermore, the bioinformatics prediction manifested voltage-dependent anion channel 1 (VDAC1) was a potential target for miR-7a-5p, and dual-luciferase reporter assay confirmed that miR-7a-5p targeted VDAC1 3' untranslated regions, which leads to the repressed expressions of VDAC1 mRNA and protein. Knockdown of VDAC1 potentiated the protective effects of miR-7a-5p against H/R-induced cell injury. In conclusion, our results demonstrated that miR-7a-5p is involved in H/R-induced cardiomyocyte apoptosis through targeting VDAC1. MiR-7a-5p/VDAC1 axis might be utilized as hopeful biomarkers to reveal the potential mechanism of myocardial I/R injury.

Lu H ，Zhang J ，Xuan F 《-》

miR-181c-5p Exacerbates Hypoxia/Reoxygenation-Induced Cardiomyocyte Apoptosis via Targeting PTPN4.

Ge L ，Cai Y ，Ying F ，Liu H ，Zhang D ，He Y ，Pang L ，Yan D ，Xu A ，Ma H ，Xia Z ... -  《-》