Single-cell RNA sequencing analysis of the temporomandibular joint condyle in 3 and 4-month-old human embryos

Qianqi Zhu; Miaoying Tan; Chengniu Wang; Yufei Chen; Chenfei Wang; Junqi Zhang; Yijun Gu; Yuqi Guo; Jianpeng Han; Lei Li; Rongrong Jiang; Xudong Fan; Huimin Xie; Liang Wang; Zhifeng Gu; Dong Liu; Jianwu Shi; Xingmei Feng

doi:10.1186/s13578-023-01069-5

Single-cell RNA sequencing analysis of the temporomandibular joint condyle in 3 and 4-month-old human embryos

Cell Biosci. 2023 Jul 19;13(1):130. doi: 10.1186/s13578-023-01069-5.

Authors

Qianqi Zhu^#¹, Miaoying Tan^#¹, Chengniu Wang^#², Yufei Chen², Chenfei Wang¹, Junqi Zhang¹, Yijun Gu¹, Yuqi Guo¹, Jianpeng Han¹, Lei Li¹, Rongrong Jiang¹, Xudong Fan¹, Huimin Xie¹, Liang Wang¹, Zhifeng Gu³, Dong Liu⁴, Jianwu Shi⁵, Xingmei Feng⁶

Affiliations

¹ Department of Stomatology, Affiliated Hospital of Nantong University, Medical School of, Nantong University, Nantong, 226001, China.
² Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China.
³ Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Medical School of, Nantong University, Nantong, 226001, China. guzf@ntu.edu.cn.
⁴ School of Life Science, Nantong Laboratory of Development and Diseases Second Affiliated Hospital Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226019, China. liudongtom@gmail.com.
⁵ Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China. jwshi@ntu.edu.cn.
⁶ Department of Stomatology, Affiliated Hospital of Nantong University, Medical School of, Nantong University, Nantong, 226001, China. xingmeifeng@ntu.edu.cn.

^# Contributed equally.

Abstract

Background: The temporomandibular joint (TMJ) is a complex joint consisting of the condyle, the temporal articular surface, and the articular disc. Functions such as mastication, swallowing and articulation are accomplished by the movements of the TMJ. To date, the TMJ has been studied more extensively, but the types of TMJ cells, their differentiation, and their interrelationship during growth and development are still unclear and the study of the TMJ is limited. The aim of this study was to establish a molecular cellular atlas of the human embryonic temporomandibular joint condyle (TMJC) by single-cell RNA sequencing, which will contribute to understanding and solving clinical problems.

Results: Human embryos at 3 and 4 months of age are an important stage of TMJC development. We performed a comprehensive transcriptome analysis of TMJC tissue from human embryos at 3 and 4 months of age using single-cell RNA sequencing. A total of 16,624 cells were captured and the gene expression profiles of 15 cell clusters in human embryonic TMJC were determined, including 14 known cell types and one previously unknown cell type, "transition state cells (TSCs)". Immunofluorescence assays confirmed that TSCs are not the same cell cluster as mesenchymal stem cells (MSCs). Pseudotime trajectory and RNA velocity analysis revealed that MSCs transformed into TSCs, which further differentiated into osteoblasts, hypertrophic chondrocytes and tenocytes. In addition, chondrocytes (CYTL1^high + THBS1^high) from secondary cartilage were detected only in 4-month-old human embryonic TMJC.

Conclusions: Our study provides an atlas of differentiation stages of human embryonic TMJC tissue cells, which will contribute to an in-depth understanding of the pathophysiology of the TMJC tissue repair process and ultimately help to solve clinical problems.

Keywords: Cellular transcriptomics; Gene expression; Human embryonic cells; TMJC.

Abstract

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