Recent data supporting any benefit of stem cell therapy for ischemic heart disease has suggested paracrine-based mechanisms via extracellular vesicles (EVs) including exosomes. We have previously engineered cardiac-derived progenitor cell (CDC) to express a peptide inhibitor, βARKct, of G protein-coupled receptor kinase 2, leading to improvements in cell proliferation, survival and metabolism. In this study we tested whether βARKct-CDC EVs would be efficacious when applied to stressed myocytes in vitro and in vivo. When isolated EVs from βARKct-CDC and control GFP-CDC were added to cardiomyocytes in culture, they both protected against hypoxia-induced apoptosis. We tested whether these EVs could protect the mouse heart in vivo following exposure either to myocardial infarction (MI) or acute catecholamine toxicity. Both types of EVs significantly protected against ischemic injury and improved cardiac function after MI compared to mice treated with EVs from mouse embryonic fibroblasts, however βARKct EVs treated mice did display some unique beneficial properties including significantly altered pro- and anti-inflammatory cytokines. Importantly, in a catecholamine toxicity model of heart failure (HF), myocardial injections of βARKct-containing EVs were superior at preventing HF compared to control EVs and this catecholamine toxicity protection was recapitulated in vitro. Therefore, introduction of the βARKct into cellular EVs can have improved reparative properties in the heart especially against catecholamine damage, which is significant since sympathetic nervous system activity is increased in HF.

中文翻译：

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βARKct 工程细胞外囊泡的表征和模型特异性心脏保护

支持干细胞治疗对缺血性心脏病的任何益处的最新数据表明，通过包括外泌体在内的细胞外囊泡 (EV) 进行基于旁分泌的机制。我们之前设计了心脏源性祖细胞 (CDC) 以表达 G 蛋白偶联受体激酶 2 的肽抑制剂 βARKct，从而改善细胞增殖、存活和代谢。在这项研究中，我们测试了 βARKct-CDC EVs 在体外和体内应用于应激肌细胞时是否有效。当从 βARKct-CDC 和对照 GFP-CDC 分离的 EV 被添加到培养的心肌细胞中时，它们都可以防止缺氧诱导的细胞凋亡。我们测试了这些 EV 是否可以在暴露于心肌梗塞 (MI) 或急性儿茶酚胺毒性后在体内保护小鼠心脏。与用来自小鼠胚胎成纤维细胞的 EVs 治疗的小鼠相比，这两种类型的 EVs 显着保护免受缺血性损伤并改善心肌功能，但是 βARKct EVs 治疗的小鼠确实表现出一些独特的有益特性，包括显着改变的促炎和抗炎细胞因子。重要的是，在心力衰竭 (HF) 的儿茶酚胺毒性模型中，与对照 EV 相比，心肌注射含 βARKct 的 EV 在预防 HF 方面具有优势，并且这种儿茶酚胺毒性保护在体外得到了概括。因此，将 βARKct 引入细胞 EV 可以改善心脏的修复特性，尤其是对抗儿茶酚胺损伤，这很重要，因为交感神经系统活动在 HF 中增加。