Exosome-mediated targeted delivery of NOX4 siRNA ameliorates angiotensin II-induced atrial fibrillation in mice

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Research Foundation of Korea BACKGROUND: Exosomes have gained attention as nanocarrier; however, the poor targeting ability after systemic administration restrict exosomes' clinical application. The targeting ability of exosomes can be improved by surface modifications. Recently, the popular method is the cell engineering technique, but cell engineering processes are complex, high-cost, time-consuming, and labor-intensive. To resolve this problem, several previous reports demonstrated exosomes are directly modified by chemical reactions (e.g., biochemical conjugation or hydrophobic insertion). However, few studies have modified exosomes with targeting ligands for atrial fibrillation. PURPOSE: This study aimed to develop exosomes endowed with heart-targeting properties using a fast and easy chemical modification method to serve as a promising therapeutic tool for atrial fibrillation. METHODS: We firstly generated heart-targeted delivery system (CTP-Exo) by engineering the surface of exosomes with cardiac targeting peptide (CTP) using bio-orthogonal copper-free click chemistry. Next, we loaded NOX4 siRNA into CTP-Exo, and NOX4 siRNA-mediated cardioprotective effects were examined in angiotensin II (Ang II)-treated human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) and mice. RESULTS: CTP-Exo had typical exosome properties, such as ~ 150 nm rounded or cup-shaped morphology, and the presence of marker proteins. Compared with unmodified-Exo, CTP-Exo specifically accumulated in the heart (P < 0.05). In addition, NOX4 siRNA-loaded CTP-Exo (siNOX4/CTP-Exo) exerted strong cardioprotective effects with excellent heart-targeting ability. In Ang II-treated iPSC-CMs, siNOX4/CTP-Exo exhibited the reduced the peak-to-peak interval variability, beating frequency, and Ca2+ transient amplitude. After intravenous injection of siNOX4/CTP-Exo in Ang II-treated mice, there was a significant improvement in cardiac function (P < 0.05) with reduced fibrosis and arrhythmia inducibility. CONCLUSION: Taken together, our results suggest that CTP-Exo function as efficient vehicles for heart-targeted delivery of siRNA, which in turn may potentially be used for the treatment of atrial fibrillation.