Figure 1

miRNAs are involved in H₂O₂-induced necrotic cell death in caridomyocytes. (a and b) H₂O₂ induces apoptosis and necrosis in cardiomyocytes. Cardiomyocytes were treated with 200 μM H₂O₂ (a) or 500 μM H₂O₂ (b) at indicated time. Apoptotic cells were analyzed by flow cytometry analysis of the active caspase-3 using the Vybrant FAM caspase-3 assay. Necrotic cell death was assessed by flow cytometry using a PI exclusion assay. (c) Microarray results depicting the log–log scatter plot of intensity of miRNA expression from control versus H₂O₂ treatment. Cardiomyocytes were untreated (control) or treated with 500 μM H₂O₂. miRNAs were detected by microarray. The red dots and the green dots indicate twofold up- or downregulated genes, respectively. (d) Upregulated miRNAs upon H₂O₂ treatment. Cardiomyocytes were treated with H₂O₂ for 24 h, and the expression of miRNAs was analyzed. (e) qRT-PCR analysis of miR-874. Cardiomyocytes were treated with H₂O₂ at the indicated time, and the expression of miR-874 was analyzed, *P<0.05 versus control. (f and g) Knockdown of miR-874 reduces necrotic responses induced by H₂O₂. Cardiomyocytes were transfected with miR-874 antagomir (anta-874) or antagomir control (anta-NC). Twenty-four hours after transfection, cells were treated with H₂O₂. Necrosis was assessed by EM (F) and PI exclusion (G), *P<0.05 versus H₂O₂ alone