Abstract Background Atrial fibrillation (AF) can develop cardiac inflammation, which contributes to atrial remodeling and ultimately leads to severe atrial fibrosis. Apoptotic Mesenchymal stem cell-derived nanovesicles (ANV) are well known for anti-inflammatory and cardioprotective effects. Experimental and clinical data indicate that patients with AF exhibit elevated expression of Adipocyte Enhancer-Binding Protein 1 (AEBP1), which is closely associated with cardiac remodeling, suggesting that targeting this gene may play a direct role in fibrosis resolution. However, the combination of ANV and AEBP1-targeting strategies has not yet been explored. Purpose In this study, we developed an enhanced treatment of AF by loading small interfering RNA targeting AEBP1 (siAEBP1) into engineered ANV, which serve as a delivery vehicle with improved targeting ability to cardiomyocytes and simultaneously knock down AEBP1 expression. Methods First, ANV was modified by conjugating anti-CD63 to capture ANV and anti-MLC3 to target cardiomyocytes in AF, thereby generating AMNV. Next, siAEBP1 was encapsulated within AMNV through electroporation, generating AMNV-siAEBP1. To evaluate its therapeutic effect in vitro, atrial cardiomyocytes differentiated from Induced pluripotent stem cells (iPSC-atrial CMs) were treated with angiotensin II (Ang II) to model AF. For in vivo experiments, an Ang II pump was implanted in mice to mimic AF. After treatment with AMNV-siAEBP1, therapeutic effects were assessed using IVIS imaging, histological staining, qRT-PCR, and western blot. Results qRT-PCR and western blot results revealed that AEBP1 expression was elevated in AF patients compared with controls (p = 0.0019), followed by the upregulation of fibrosis markers (Collagen I, β-catenin, c-MYC, and COL1A2; p 0.05). This was also verified in Ang II-treated iPSC-atrial CMs (p = 0.0343). Notably, we confirmed that AEBP1 is involved in the AF-related fibrosis pathway. Silencing AEBP1 expression significantly downregulated its levels (p 0.001), reduced fibrosis-related gene expression (COL1A2, Collagen I), and alleviated oxidative stress (p 0.01), showing improvements in cardiac fibrosis. In vivo, AMNV treatment alone reduced pro-inflammatory markers (IL-1β, TNFα; p 0.01) and enhanced targeting efficiency to the AF heart (p 0.01). Treatment with AMNV-siAEBP1 further improved ejection fraction and reduced fibrosis-related markers (α-SMA; p = 0.0071, COL1A2, Collagen I, and COL3A1; p 0.0001) along with the downregulation of pro-inflammatory markers (IL-1β, TNFα; p 0.001), enhancing therapeutic effects compared to AMNV treatment alone. Histological analysis revealed reduced fibrosis and partial recovery of cardiac inflammation, demonstrating its potential as a cardioprotective therapy. Conclusion(s) In conclusion, engineered apoptotic MSC-derived nanovesicles encapsulating siAEBP1 could serve as an effective therapeutic approach for enhanced treatment in AF.Graphical abstract
Yoo et al. (Sat,) studied this question.