Figure 3.

miR-15b-5p regulates oxidative metabolism in cardiac cells. (A) Increase in JO₂ upon cytochrome c addition following digitonin permeabilization in differentiated H9c2 cells transfected with a miR-15b-5p mimic compared to cells transfected with a negative control mimic. Four iterations of this experiment were performed. Negative control n = 4, miR-15b-5p mimic n = 4. (B) mtDNA:nDNA ratio calculated by relative Nd5:Rplp0 amplification in differentiated H9c2 cells transfected with a miR-15b-5p mimic compared to cells transfected with a negative control mimic. Three iterations of this experiment were performed. Negative control n = 11, miR-15b-5p mimic n = 11. (C) Estimated relative fatty acid oxidation in H9c2 cells transfected with a miR-15b-5p mimic compared to cells transfected with a negative control mimic. Three iterations of this experiment were performed. Negative control n = 7, miR-15b-5p mimic n = 9. One outlier removed from NC group (ROUT Q = 1 %). (D) Relative MTT staining in differentiated H9c2 cells cultured at standard (O₂ = 20 %) and hypoxic conditions (O₂ = 1 %) conditions transfected with a miR-15b-5p antisense compared to cells transfected with a negative control oligo. Negative control n = 6, miR-15b-5p mimic n = 6. (E) Estimated relative fatty acid oxidation in H9c2 cells transfected with a miR-15b-5p mimic compared to cells transfected with a negative control mimic. Three iterations of this experiment were performed. Negative control n = 9, miR-15b-5p mimic n = 9. (F) Relative MTT staining in differentiated H9c2 cells cultured at normoxic (O₂ = 20 %) and hypoxic conditions (O₂ = 1 %) conditions transfected with a miR-15b-5p antisense compared to cells transfected with a negative control oligo. Negative control n = 6, miR-15b-5p antisense n = 6. Figures B, C and E: statistical significance calculated by linear mixed-effects models with iteration as random effect. Figures D and F: statistical significance calculated by unpaired two-tailed Student t-test.