Cardiac progenitor cell (CPC)-derived small extracellular vesicles (sEVs) exhibit great potential to stimulate cardiac repair. However, the multifaceted nature of sEV heterogeneity presents a challenge in understanding the distinct mechanisms underlying their regenerative abilities. Here, a dual-step multimodal flowthrough and size-exclusion chromatography method was applied to isolate and separate CPC-derived sEV subpopulations to study the functional differences related to cardiac repair responses. Three distinct sEV subpopulations were identified with unique protein profiles. Functional cell assays for cardiac repair-related processes demonstrated that the middle-sized and smallest-sized sEV subpopulations exhibited the highest pro-angiogenic and anti-fibrotic activities. Proteasome activity was uniquely seen in the smallest-sized subpopulation. The largest-sized subpopulation showed no effect in any of the functional assays. This research uncovers the existence of sEV subpopulations, each characterized by a distinct composition and biological function. Enhancing our understanding of sEV heterogeneity will provide valuable insights into sEV mechanisms of action, ultimately accelerating the translation of sEV therapeutics.

中文翻译：

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大小很重要：小细胞外囊泡亚群在心脏修复反应中的功能差异

心脏祖细胞（CPC）衍生的小细胞外囊泡（sEV）表现出刺激心脏修复的巨大潜力。然而，sEV 异质性的多方面性质对理解其再生能力背后的不同机制提出了挑战。在这里，应用双步多模式流通和尺寸排阻色谱方法来分离和分离 CPC 衍生的 sEV 亚群，以研究与心脏修复反应相关的功能差异。三个不同的 sEV 亚群被鉴定为具有独特的蛋白质谱。心脏修复相关过程的功能细胞测定表明，中等大小和最小大小的 sEV 亚群表现出最高的促血管生成和抗纤维化活性。蛋白酶体活性在最小的亚群中是独特的。最大的亚群在任何功能测定中都没有显示出任何影响。这项研究揭示了 sEV 亚群的存在，每个亚群都有独特的组成和生物学功能。增强我们对 sEV 异质性的理解将为 sEV 作用机制提供有价值的见解，最终加速 sEV 疗法的转化。