Objective To explore the functional impact of A-to-I editing in the seed region of miR-411 during post-myocardial infarction (MI) fibrosis and elucidate its therapeutic potential.
Methods Integrating GEO database with myocardial RNA-seq data from MI mouse models, we identified dynamic A-to-I RNA editing in small noncoding RNAs across MI progression (1 day to 8 weeks post-MI). Four miRNAs exhibited differential editing rates between MI and controls, with miR-411 showing progressive editing enhancement at seed region position 4 (P＜0.01). This editing event was validated in both murine MI models and human heart failure specimens.
Results The A-to-I editing ratio change of the 4th nucleotide in the seed region of miR-411 mainly occurs in cardiac fibroblasts rather than cardiomyocytes, and the editing at this site depends on ADAR2 rather than ADAR1. Edited miR-411 (ED-miR-411) diverged from wild-type miR-411 (WT-miR-411) in suppressing collagen-related pathways (extracellular matrix ECM-receptor interaction, collagen-containing ECM, ECM organization; P＜0.01) in cardiac fibroblasts. Mechanistically, dual-luciferase assays confirmed ED-miR-411 directly targeted the 3′UTR and suppressed expression of type Ⅱ transforming growth factor (TGF)-beta receptor (TGFBR2) and CD44, which were key drivers of TGF-β-mediated fibroblast activation. ED-miR-411 overexpression blunted TGF-β-induced collagen synthesis and myofibroblast proliferation (P＜0.05). In vivo, intramyocardial delivery of ED-miR-411 mimics at 1 week post-MI reduced fibrosis by 40% and improved ejection fraction by 15% (P＜0.01 vs controls), whereas WT-miR-411 showed no therapeutic effect.
Conclusions A-to-I editing of miR-411 emerges as an endogenous anti-fibrotic mechanism by repressing TGFBR2 and CD44, thereby disrupting TGF-β signaling and ECM dysregulation. Our findings highlight ED-miR-411 as a novel RNA-based therapeutic candidate to mitigate post-infarction cardiac remodeling.
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