Figure 4.

miR-146a ameliorates A/R-induced mitochondrial dysfunction in cardiomyocytes

(A) Cardiomyocytes were treated with miR-146a mimics or miR-146a inhibitor for 24 h prior to A/R stimulation for 48 h and then with AngII (10 μM) for another 24 h. Mitochondrial membrane potential was measured using JC-1 staining. Representative images of JC-1-derived fluorescence in cardiomyocytes are shown in the left panel. JC-1 aggregate image displays red fluorescence, JC-1 monomer image displays green fluorescence, and the merged image combines red and green fluorescence images. Quantitative analysis of the green/red fluorescence ratio is provided in the right panel. (B and C) Opening of mitochondrial permeability transition pore in cardiomyocytes treated with miR-146a mimics (B) or miR-146a inhibitor (C) under A/R conditions was detected by calcein-AM staining. (D and E) Cytochrome c protein expression in the cytosol and mitochondria was determined by western blot. Transfection with miR-146a mimics inhibited the release of cytochrome c into the cytosol (D), whereas miR-146a inhibitor promoted the release of cytochrome c (E). Mitochondrial marker protein Tom20 was used as an internal control. ∗∗p < 0.01 versus NC-m control or NC-i control; ^##p < 0.01 versus NC-m A/R or NC-i A/R, n = 6–8.