miR-519e and miR-4784 promote cardiomyocyte proliferation and survival without increasing fibrosis or impairing angiogenesis, suggesting therapeutic potential for heart repair.
In a multicellular in vitro model, miR-519 and miR-4784 demonstrated synergistic regenerative capacities without detrimental cell-specific effects, suggesting potential therapeutic utility for cardiac repair after myocardial infarction.
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Abstract Background Endogenous heart regeneration after myocardial infarction (MI) relies on coordinated interaction of cardiomyocyte (CM) cell-cycle re-entry, neoangiogenesis and activation of fibroblasts, with microRNAs (miR) emerging as critical modulators of cardiac repair processes. Whereas multiple miRs have been discovered for induction of CM proliferation, cell-specific roles to uncover synergistic pathways for multicellular cardiac repair have been rarely explored. Purpose Derived from a functional high-throughput screening investigating 2019 miR-mimics for proliferation in human induced pluripotent stem cell-derived CMs (hiPSC-CM), we tested 11 candidate miR-mimics on a multicellular level. Methods Individual miRs were overexpressed in hiPSC-CMs, human aortic endothelial cells (HAEC) and cardiac fibroblasts (cFB) using a lipid-based transfection. MiR-scramble (miR-scr) served as control. Functional assays were performed to investigate proliferation, cytokinesis and apoptosis in hiPSC-CM, tube formation in HAECs and fibroblast-to-myofibroblast transition after TGF-β stimulation in cFBs. Results We tested pro-proliferative activity of miR-mimic-transfected hiPSC-CM using EdU-incorporation and validated 10 out of 11 tested miR-mimics, including 7 miR-mimics that increased Aurora B-kinase staining in hiPSC-CM (p0.05 for all as compared to miR-scr). 3 of the tested miR-mimics enhanced angiogenic potential, as assessed in tube formation assays (p0.05 for total meshes and tube length as compared to miR-scr). Intriguingly, miR-3150b induced cytokinesis in hiPSC-CM, but blunted angiogenic capacity in HAECs after miR-overexpression. MiRs with the highest cardiomyogenic and angiogenic capacity, namely miR-519e, miR-4461 and miR-4784 were further explored for potential detrimental biological effects. Herein, individual miR-519 transfection did not alter Doxorubicin-induced hiPSC-CMs apoptosis, yet with preserved cell survival after miR-4784 and miR-4461-mimic transfection (p0.01 for cell viability (%) as compared to miR-scr). In addition, whereas the 3 miRs did not alter cFB-proliferation, miR-4461 activated cFBs (p0.01 for α-SMA+ cFB after TGF-β stimulation as compared to miR-scr), suggesting CM proliferation at the expense of increased fibrosis for miR-4461 and decreased neoangiogenesis for miR-3150b. Conclusion Using a functional multicellular approach of selected miRs with regenerative capacity in hiPSC-CMs, we show miR-dependent synergistic but also potential cell-specific detrimental biological functions that interfere with the regenerative potential. This study underscores the diverse action of miRs in different cell types involved in cardiac repair processes. In conclusion, our multicellular approach suggests that miR-519 and miR-4784 induce cardiac repair processes relevant for cardiac regeneration in vitro and therefore may be used as a therapeutic strategy for repair processes after MI or in ischemia-driven cardiomyopathy.
Gong et al. (Sat,) reported a other. miR-519e and miR-4784 promote cardiomyocyte proliferation and survival without increasing fibrosis or impairing angiogenesis, suggesting therapeutic potential for heart repair.