Retinal degeneration (RD), a group of diseases leading to irreversible vision loss, is characterised by retinal pigment epithelium (RPE) or retinal neuron damage and loss. With fewer risks of immune rejection and tumorigenesis, stem cell-secreted extracellular vesicles (EVs) offer a new cell-free therapeutic paradigm for RD, which remains to be investigated. Human retinal organoid-derived retinal progenitor cells (hERO-RPCs) are an easily accessible and advanced cell source for RD treatment. However, hERO-RPCs-derived EVs require further characterisation. Here, we compared the characteristics of EVs from hERO-RPCs (hRPC-EVs) with those of human embryonic stem cell (hESC)-derived EVs (hESC-EVs) as controls. Based on in-depth proteomic analysis, we revealed remarkable differences between hRPC-EVs and hESC-EVs. A comparison between EVs and their respective cells of origin demonstrated that the protein loading of hRPC-EVs was more selective than that of hESC-EVs. In particular, hESC-EVs were enriched with proteins related to angiogenesis and cell cycle, whereas hRPC-EVs were enriched with proteins associated with immune modulation and retinal development. More importantly, compared with that of hESC-EVs, hRPC-EVs exhibited a lower correlation with cell proliferation and a unique capacity to regulate lipid metabolism. It was further confirmed that hRPC-EVs potentially eliminated lipid deposits, inhibited lipotoxicity and oxidative stress, and enhanced phagocytosis and survival of oleic acid-treated ARPE-19 cells. Mechanistically, hRPC-EVs are integrated into the mitochondrial network of oleic acid-treated ARPE-19 cells, and increased the level of mitochondrial fatty acid β-oxidation-related proteins. Thus, organoid-derived hRPC-EVs represent a promising source of cell-free therapy for RD, especially for blinding diseases related to abnormal lipid metabolism in RPE cells.

中文翻译：

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来自类器官来源的人视网膜祖细胞的细胞外囊泡通过调节脂肪酸代谢来预防脂质超负荷诱导的视网膜色素上皮损伤

视网膜变性（RD）是一组导致不可逆视力丧失的疾病，其特征是视网膜色素上皮（RPE）或视网膜神经元损伤和丧失。由于免疫排斥和肿瘤发生的风险较小，干细胞分泌的细胞外囊泡（EV）为 RD 提供了一种新的无细胞治疗范例，这一范例仍有待研究。人视网膜类器官来源的视网膜祖细胞 (hERO-RPC) 是一种易于获取且先进的 RD 治疗细胞来源。然而，hERO-RPC 衍生的 EV 需要进一步表征。在这里，我们将来自 hERO-RPC (hRPC-EV) 的 EV 的特征与作为对照的人胚胎干细胞 (hESC) 衍生的 EV (hESC-EV) 的特征进行了比较。基于深入的蛋白质组学分析，我们揭示了 hRPC-EV 和 hESC-EV 之间的显着差异。EV 与其各自的来源细胞之间的比较表明，hRPC-EV 的蛋白质负载比 hESC-EV 的蛋白质负载更具选择性。特别是，hESC-EV 富含与血管生成和细胞周期相关的蛋白质，而 hRPC-EV 富含与免疫调节和视网膜发育相关的蛋白质。更重要的是，与hESC-EVs相比，hRPC-EVs与细胞增殖的相关性较低，并且具有独特的脂质代谢调节能力。进一步证实，hRPC-EVs 可能消除脂质沉积，抑制脂毒性和氧化应激，并增强油酸处理的 ARPE-19 细胞的吞噬作用和存活率。从机制上讲，hRPC-EV 整合到油酸处理的 ARPE-19 细胞的线粒体网络中，并增加了线粒体脂肪酸 β-氧化相关蛋白的水平。因此，类器官衍生的 hRPC-EV 代表了 RD 无细胞疗法的一个有前途的来源，特别是与 RPE 细胞脂质代谢异常相关的致盲疾病。