Cargo-defined engineered vesicles enable targeted miRNA delivery for cardiac repair after myocardial infarction.

Myocardial infarction (MI) remains a leading cause of morbidity and mortality worldwide, and current therapeutic strategies offer limited efficacy in promoting long-term cardiac repair. miRNAs have emerged as promising therapeutic agents owing to their capacity to modulate gene networks involved in cardiomyocyte apoptosis, mitochondrial dysfunction, and extracellular matrix (ECM) remodeling. Herein, we identified miR-30d as a potential therapeutic target, exhibiting dynamic expression changes in plasma extracellular vesicles (EVs) from MI patients before and after percutaneous coronary intervention (PCI). To facilitate targeted delivery, we developed an engineered milk-derived EV-like vehicle (mELV) system in which endogenous RNAs were depleted via sonication to reduce off-target effects and improve cargo uniformity. These mELVs were further loaded with miR-30d and subsequently functionalized with an ischemic myocardium targeting peptide (IMTP). Intravenous administration of miR30d-mELVsIMTP in murine MI model conferred both acute cardioprotection and sustained improvements in cardiac function, accompanied by reduced pathological remodeling. Mechanistically, miR-30d directly targets Thbs2, leading to suppression of downstream MMP2 expression, attenuation of mitochondrial reactive oxygen species production, and inhibition of ECM degradation. Collectively, these findings underscore the therapeutic potential of miR-30d and establish programmable RNA-depleted, IMTP-conjugated mELVs as a safe, targeted, and effective platform for miRNA delivery in post-MI gene therapy.