Mesenchymal stromal cells (MSCs) are multipotent, progenitor cells that reside in tissues across the human body, including the periodontal ligament (PDL) and gingiva. They are a promising therapeutic tool for various degenerative and inflammatory diseases. However, different heterogeneity levels caused by tissue-to-tissue and donor-to-donor variability, and even intercellular differences within a given MSCs population, restrict their therapeutic potential. There are considerable efforts to decipher these heterogeneity levels using different “omics” approaches, including single-cell transcriptomics. Previous studies applied this approach to compare MSCs isolated from various tissues of different individuals, but distinguishing between donor-to-donor and tissue-to-tissue variability is still challenging. In this study, MSCs were isolated from the PDL and gingiva of 5 periodontally healthy individuals and cultured in vitro. A total of 3,844 transcriptomes were generated using single-cell mRNA sequencing. Clustering across the 2 different tissues per donor identified PDL- and gingiva-specific and tissue-spanning MSCs subpopulations with unique upregulated gene sets. Gene/pathway enrichment and protein-protein interaction (PPI) network analysis revealed differences restricted to several cellular processes between tissue-specific subpopulations, indicating a limited tissue-of-origin variability in MSCs. Gene expression, pathway enrichment, and PPI network analysis across all donors’ PDL- or gingiva-specific subpopulations showed significant but limited donor-to-donor differences. In conclusion, this study demonstrates tissue- and donor-specific variabilities in the transcriptome level of PDL- and gingiva-derived MSCs, which seem restricted to specific cellular processes. Identifying tissue-specific and tissue-spanning subpopulations highlights the intercellular differences in dental tissue–derived MSCs. It could be reasonable to control MSCs at a single-cell level to ensure their properties before transplantation.

中文翻译：

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单细胞 RNA-seq 揭示的牙齿组织来源的 MSC 的异质性


间充质基质细胞 （MSC） 是多能祖细胞，存在于人体组织中，包括牙周韧带 （PDL） 和牙龈。它们是治疗各种退行性和炎症性疾病的有前途的工具。然而，由组织间和供体间供体间的变异性引起的不同异质性水平，甚至给定 MSCs 群体内的细胞间差异，都限制了它们的治疗潜力。使用不同的“组学”方法（包括单细胞转录组学）来破译这些异质性水平付出了相当大的努力。以前的研究应用这种方法来比较从不同个体的各种组织中分离的 MSC，但区分供体间和组织间的变异性仍然具有挑战性。在这项研究中，从 5 名牙周健康个体的 PDL 和牙龈中分离出 MSCs，并在体外培养。使用单细胞 mRNA 测序共产生 3,844 个转录组。每个供体在 2 个不同组织中聚类确定了具有独特上调基因集的 PDL 和牙龈特异性和跨组织 MSCs 亚群。基因/通路富集和蛋白质-蛋白质相互作用 （PPI） 网络分析揭示了组织特异性亚群之间仅限于多个细胞过程的差异，表明 MSC 的组织来源变异性有限。所有供体的 PDL 或牙龈特异性亚群的基因表达、通路富集和 PPI 网络分析显示供体间差异显著但有限。总之，本研究证明了 PDL 和牙龈衍生的 MSC 转录组水平的组织特异性和供体特异性差异，这似乎仅限于特定的细胞过程。 鉴定组织特异性和跨组织亚群突出了牙组织来源的 MSC 的细胞间差异。在单细胞水平上控制 MSC 以确保其移植前的特性可能是合理的。