# Injured cardiac targeting magnetic nanovesicles for mRNA treatment of myocardial infarction

## TL;DR

This study develops magnetic nanovesicles to deliver anti-inflammatory mRNA to damaged heart tissue, improving recovery after heart attacks.

## Contribution

A dual-active magnetic nanocarrier system for targeted mRNA delivery to injured cardiac tissue is engineered.

## Key findings

- m10@T-MNVs showed a 4.5-fold increase in accumulation in injured cardiomyocytes under a magnetic field.
- In mice, m10@T-MNVs reduced tissue injury, fibrosis, and pathological remodeling after myocardial infarction.
- The treatment enhanced IL-10 mRNA expression and promoted anti-inflammatory macrophage polarization.

## Abstract

Rationale: Inflammation and myocardial remodeling are major contributors to the progression of cardiac diseases. mRNA-based therapeutics have emerged as a promising modality for cardiovascular intervention; however, their clinical translation remains constrained by challenges in achieving efficient and spatially precise delivery to diseased cardiac tissue, particularly following myocardial injury. To address this unmet need, a dual-active magnetic nanocarrier was engineered for targeted mRNA delivery to damaged cardiovascular tissue.

Methods: The interleukin-10 anti-inflammatory cytokine mRNA (IL-10 mRNA) was encapsulated in lipid nanoparticles, which were fused with nanovesicles derived from mesenchymal stem cells (NVs) and functionalized with cardiac-targeting peptides (T peptides) to form IL-10 mRNA-loaded T-NVs (m10@T-NVs). Magnetic nanoparticles (MNPs) were conjugated with azide-modified antibodies against CD63 and myosin light chain 3 (MLC3), which are overexpressed in damaged myocardial tissue via click chemistry, to enable targeted delivery to injured cardiac tissue. Subsequently, the m10@T-NVs were combined with functionalized MNPs via CD63 interactions to form m10@T-MNVs.

Results:
m10@T-MNVs were developed and characterized, confirming the functionalization of NVs and MNPs. Under guided of an external magnetic field, m10@T-MNVs exhibited a 4.5-fold increase in accumulation in H2O2-induced injured cardiomyocytes and damaged cardiac regions, achieving significantly higher delivery efficiency. In a mouse model of myocardial infarction (MI), administration of m10@T-MNVs enhanced intramyocardial IL-10 mRNA expression and cytokine production. This led to the polarization of macrophages toward an M2 anti-inflammatory phenotype, mitigation of tissue injury, reduced apoptosis, attenuation of fibrosis, and suppression of pathological myocardial remodeling.

Conclusions: Dual-active targeting of injured cardiac tissue using magnetic nanocarriers constitutes a promising therapeutic strategy for cardiovascular diseases by addressing key challenges associated with tissue-selective mRNA delivery in the injured myocardium.