The Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University, Jerusalem, Israel.
Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA.
J Dent Res. 2021 Aug;100(9):897-905. doi: 10.1177/00220345211001848. Epub 2021 Mar 25.
The systematic classification of the cells that compose a tissue or an organ is key to understanding how these cells cooperate and interact as a functional unit. Our capacity to detect features that define cell identity has evolved from morphological and chemical analyses, through the use of predefined genetic markers, to unbiased transcriptomic and epigenetic profiling. The innovative technology of single-cell RNA sequencing (scRNA-seq) enables transcriptional profiling of thousands of individual cells. Since its development, scRNA-seq has been extensively applied to numerous organs and tissues in a wide range of animal models and human samples, thereby providing a plethora of fundamental biological insights into their development, homeostasis, and pathology. In this review, we present the findings of 3 recent studies that employed scRNA-seq to unravel the complexity of cellular composition in mammalian teeth. These findings offer an unprecedented catalogue of cell types in the mouse incisor, which is a convenient model system for studying continuous tooth growth. These studies identified novel cell types in the tooth epithelium and mesenchyme, as well as new markers for known cell types. Computational analyses of the data also uncovered the lineage and dynamics of cell states during ameloblast and odontoblast differentiation during both normal homeostasis and injury repair. The transcriptional differences between the mouse incisor and mouse and human molars uncover species-specific as well as shared features in tooth cell composition. Here, we highlight these findings and discuss important similarities and differences between these studies. We also discuss potential future applications of scRNA-seq in dental research and dentistry. Together, these studies demonstrate how the rapidly evolving technology of scRNA-seq can advance the study of tooth development and function and provide putative targets for regenerative approaches.
细胞构成组织或器官的系统分类是理解这些细胞如何作为一个功能单元合作和相互作用的关键。我们检测定义细胞身份的特征的能力已经从形态和化学分析发展到使用预定义的遗传标记，再到无偏转录组学和表观遗传分析。单细胞 RNA 测序（scRNA-seq）的创新技术能够对数千个单个细胞进行转录组分析。自其发展以来，scRNA-seq 已广泛应用于多种动物模型和人类样本的众多器官和组织中，从而为它们的发育、稳态和病理学提供了大量的基本生物学见解。在这篇综述中，我们介绍了最近的 3 项研究的结果，这些研究利用 scRNA-seq 揭示了哺乳动物牙齿细胞组成的复杂性。这些发现提供了一个前所未有的鼠标切牙细胞类型目录，这是一个研究连续牙齿生长的方便模型系统。这些研究在牙齿上皮和间充质中发现了新的细胞类型，以及已知细胞类型的新标志物。对数据的计算分析还揭示了在正常稳态和损伤修复期间成釉细胞和成牙本质细胞分化过程中细胞状态的谱系和动态。小鼠切牙和小鼠和人磨牙之间的转录差异揭示了牙齿细胞组成的物种特异性和共享特征。在这里，我们强调了这些发现，并讨论了这些研究之间的重要相似性和差异。我们还讨论了 scRNA-seq 在牙科研究和牙科中的潜在未来应用。这些研究共同证明了 scRNA-seq 这一快速发展的技术如何推进牙齿发育和功能的研究，并为再生方法提供潜在的目标。
