Fig. 5

Selected miRNAs differentially regulate calcium handling, contractile properties, and metabolism markers of hiPSC-CMs TROPO-GFP at D30. A Top left: Schematic presenting parameters used to describe the Ca²⁺ transient, including amplitude (deltaF/F₀) and Ca²⁺ DT₉₀ (time to 90% Ca²⁺ decay, ms). Bottom left: Representative Ca²⁺ transients of control (dashed black line) and miR-124-treadted cells (solid blue line). Top right: Box plot of amplitude and Ca²⁺ DT₉₀ (N = 4–6 independent experiments). Bottom right: Box plot of SERCA2 a/b mean fluorescence intensity (N = 4 independent differentiation experiments). B Top left: Schematic contraction–relaxation curve of beating hiPSC-CMs highlighting contractile parameters evaluated in this study. Bottom left: Representative contraction–relaxation curves of control (dashed black line) and miR-124-treated cells (solid blue line). Box plots of frequency, average contraction–relaxation time (Top right), average contraction speed, and maximum relaxation speed (Bottom right). Dashed lines represent the median of control cells in each graph (N = 4–6 independent differentiation experiments). C Representative confocal micrographs of control and miRNA-treated cells stained for ssTnI and Tom20 by immunofluorescence and D quantitative analysis of Tom20 mean fluorescence intensity (N = 91–142 cells per treatment from one differentiation experiment in two independent transient transfections). E Mitochondrial distribution (Tom20 Fluorescence) groups Ctrl e miR-124-3p-treated cells (N = 4 independent differentiation experiments). F Relative TMRM Intensity and (G) % of cell TUNEL.⁺. Dashed lines represent the median of control cells in each graph. Statistical significance treatment vs control (Ctrl) are represented as * p < 0.05, ** p < 0.001, *** p < 0.001