Cellular skin substitutes such as epidermal constructs have been developed for various applications, including wound healing and skin regeneration. These cellular models are mostly derived from primary cells such as keratinocytes and fibroblasts in a two-dimensional (2D) state, and further development of three-dimensional (3D) cultured organoids is needed to provide insight into the epidermal phenotype and physiology. Here, we report the development of epidermal organoids (EpiOs) generated from induced pluripotent stem cells (iPSCs) as a novel epidermal construct and its application as a source of secreted biomolecules recovered by extracellular vesicles (EVs) that can be utilized for cell-free therapy of regenerative medicine. Differentiated iPSC-derived epidermal organoids (iEpiOs) are easily cultured and expanded through multiple organoid passages, while retaining molecular and functional features similar to epidermis. These mature iEpiOs contain epidermal stem cell populations and retain the ability to further differentiate into other skin compartment lineages, such as hair follicle stem cells. By closely recapitulating the epidermal structure, iEpiOs are expected to provide a more relevant microenvironment to influence cellular processes and therapeutic response. Indeed, iEpiOs can generate high-performance EVs containing high levels of the angiogenic growth factor VEGF and miRNAs predicted to regulate cellular processes such as proliferation, migration, differentiation, and angiogenesis. These EVs contribute to target cell proliferation, migration, and angiogenesis, providing a promising therapeutic tool for wound healing. Overall, the newly developed iEpiOs strategy as an organoid-based approach provides a powerful model for studying basic and translational skin research and may also lead to future therapeutic applications using iEpiOs-secreted EVs.

中文翻译：

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开发多能干细胞衍生的表皮类器官，在皮肤再生中产生有效的细胞外囊泡

表皮结构等细胞皮肤替代品已被开发用于各种应用，包括伤口愈合和皮肤再生。这些细胞模型大多源自二维（2D）状态的角质形成细胞和成纤维细胞等原代细胞，需要进一步开发三维（3D）培养类器官以深入了解表皮表型和生理学。在这里，我们报告了诱导多能干细胞（iPSC）产生的表皮类器官（EpiOs）作为一种新型表皮构建体的发展，及其作为细胞外囊泡（EV）回收的分泌生物分子来源的应用，可用于无细胞培养再生医学疗法。分化的 iPSC 衍生的表皮类器官 (iEpiOs) 可以通过多个类器官通道轻松培养和扩增，同时保留与表皮相似的分子和功能特征。这些成熟的 iEpiO 含有表皮干细胞群，并保留进一步分化为其他皮肤区系谱系的能力，例如毛囊干细胞。通过密切再现表皮结构，iEpiO 有望提供更相关的微环境来影响细胞过程和治疗反应。事实上，iEpiO 可以产生高性能 EV，其中含有高水平的血管生成生长因子 VEGF 和 miRNA，预计可调节增殖、迁移、分化和血管生成等细胞过程。这些 EV 有助于靶细胞增殖、迁移和血管生成，为伤口愈合提供了一种有前景的治疗工具。总体而言，新开发的 iEpiOs 策略作为一种基于类器官的方法，为研究基础和转化皮肤研究提供了强大的模型，并且还可能导致使用 iEpiOs 分泌的 EV 的未来治疗应用。