OBJECTIVES Critical hindlimb ischemia is a severe consequence of peripheral artery disease. Surgical treatment does not prevent skeletal muscle impairment or improve long-term patient outcomes. The present study investigates the protective/regenerative potential and the mechanism of action of adipose stem cell-derived extracellular vesicles (ASC-EVs) in a mouse model of hindlimb ischemia. Approach and Results: We demonstrated that ASC-EVs exert a protective effect on muscle damage by acting both on tissue microvessels and muscle cells. The genes involved in muscle regeneration were up-regulated in the ischemic muscles of ASC-EV-treated animals. MyoD expression has also been confirmed in satellite cells. This was followed by a reduction in muscle function impairment in vivo. ASC-EVs drive myoblast proliferation and differentiation in the in vitro ischemia/reoxygenation model. Moreover, ASC-EVs have shown an anti-apoptotic effect both in vitro and in vivo. Transcriptomic analyses have revealed that ASC-EVs carry a variety of pro-angiogenic mRNAs, while proteomic analyses have demonstrated an enrichment of NRG1 (neuregulin 1). A NRG1 blocking antibody used in vivo demonstrated that NRG1 is relevant to ASC-EV-induced muscle protection, vascular growth, and recruitment of inflammatory cells. Finally, bioinformatic analyses on 18 molecules that were commonly detected in ASC-EVs, including mRNAs and proteins, confirmed the enrichment of pathways involved in vascular growth and muscle regeneration/protection. CONCLUSIONS This study demonstrates that ASC-EVs display pro-angiogenic and skeletal muscle protective properties that are associated with their NRG1/mRNA cargo. We, therefore, propose that ASC-EVs are a useful tool for therapeutic angiogenesis and muscle protection.

中文翻译：

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来自脂肪干细胞的细胞外囊泡可在后肢缺血小鼠模型中预防肌肉损伤和炎症：Neuregulin-1的作用。

目的严重的后肢缺血是外周动脉疾病的严重后果。手术治疗不能预防骨骼肌损伤或改善长期患者的预后。本研究探讨了脂肪干细胞衍生的细胞外囊泡（ASC-EVs）在后肢缺血小鼠模型中的保护/再生潜力和作用机理。方法和结果：我们证明了ASC-EVs通过对组织微血管和肌肉细胞的作用而对肌肉损伤起到保护作用。在ASC-EV治疗的动物的缺血性肌肉中，参与肌肉再生的基因上调。还已经在卫星细胞中证实了MyoD表达。随后是体内肌肉功能损伤的减轻。ASC-EV在体外缺血/复氧模型中驱动成肌细胞增殖和分化。此外，ASC-EV在体外和体内均显示出抗凋亡作用。转录组分析显示ASC-EV携带多种促血管生成的mRNA，而蛋白质组分析已证明NRG1（神经调节蛋白1）富集。体内使用的NRG1阻断抗体证明NRG1与ASC-EV诱导的肌肉保护，血管生长和炎症细胞募集有关。最后，对ASC-EV中常见的18种分子（包括mRNA和蛋白质）进行的生物信息学分析证实了参与血管生长和肌肉再生/保护的途径的丰富性。结论这项研究表明ASC-EVs具有与其NRG1 / mRNA货物相关的促血管生成和骨骼肌保护特性。因此，我们提出ASC-EVs是用于治疗性血管生成和肌肉保护的有用工具。