Objective:To utilize single-cell RNA sequencing (scRNA-seq) to untangle the temporal expression profiles of molecules associated with congenital tooth agenesis and dental hard tissue formation during mouse molar development, and to construct a comprehensive cell atlas spanning the entire developmental period from E13.5 to P7.5, thereby providing new insights into the molecular mechanisms underlying abnormal tooth development.Methods:scRNA-seq data of murine mandibular molar tooth germs at five developmental stages (E13.5, E14.5, E16.5, P3.5, P7.5) were obtained from the GEO database (accession: GSE189381). The Seurat pipeline was employed for quality control, data normalization, dimensionality reduction, and Harmony-based batch effect correction. Cellular subpopulations were identified through uniform manifold approximation and projection dimensionality reduction, while developmental trajectories were reconstructed using Monocle for pseudotime analysis.Results:scRNA-seq analysis profiling identified 27 distinct cellular clusters, which were annotated into twelve major cell types including epithelial cells, mesenchymal cells, and endothelial cells. Msx1 exhibited a bimodal expression pattern. Pax9 reached its peak at E14.5 and then gradually decreased. Eda had a low expression level with a diffuse distribution. In contrast, Amelx and Enam were barely expressed during the embryonic stage and were activated at P3.5. Dspp was ectopically highly expressed in epithelial cells from P3.5 to P7.5, while Dmp1 was specifically upregulated in mesenchymal cells at P7.5.Conclusions:The temporal expression patterns of key regulatory genes for tooth agenesis (Msx1, Pax9, Eda), ameloblast differentiation (Amelx, Enam), and odontoblast development (Dspp, Dmp1) during mouse molar development. These findings provide a theoretical foundation and potential therapeutic targets for deciphering the molecular mechanisms underlying tooth agenesis and other developmental dental anomalies, paving the way for targeted clinical interventions.

Objective:To utilize single-cell RNA sequencing (scRNA-seq) to untangle the temporal expression profiles of molecules associated with congenital tooth agenesis and dental hard tissue formation during mouse molar development, and to construct a comprehensive cell atlas spanning the entire developmental period from E13.5 to P7.5, thereby providing new insights into the molecular mechanisms underlying abnormal tooth development.Methods:scRNA-seq data of murine mandibular molar tooth germs at five developmental stages (E13.5, E14.5, E16.5, P3.5, P7.5) were obtained from the GEO database (accession: GSE189381). The Seurat pipeline was employed for quality control, data normalization, dimensionality reduction, and Harmony-based batch effect correction. Cellular subpopulations were identified through uniform manifold approximation and projection dimensionality reduction, while developmental trajectories were reconstructed using Monocle for pseudotime analysis.Results:scRNA-seq analysis profiling identified 27 distinct cellular clusters, which were annotated into twelve major cell types including epithelial cells, mesenchymal cells, and endothelial cells. Msx1 exhibited a bimodal expression pattern. Pax9 reached its peak at E14.5 and then gradually decreased. Eda had a low expression level with a diffuse distribution. In contrast, Amelx and Enam were barely expressed during the embryonic stage and were activated at P3.5. Dspp was ectopically highly expressed in epithelial cells from P3.5 to P7.5, while Dmp1 was specifically upregulated in mesenchymal cells at P7.5.Conclusions:The temporal expression patterns of key regulatory genes for tooth agenesis (Msx1, Pax9, Eda), ameloblast differentiation (Amelx, Enam), and odontoblast development (Dspp, Dmp1) during mouse molar development. These findings provide a theoretical foundation and potential therapeutic targets for deciphering the molecular mechanisms underlying tooth agenesis and other developmental dental anomalies, paving the way for targeted clinical interventions.

Objective: To detect and analyze the differential expression profile of long non-coding RNA (lncRNA) in aggressive periodontitis (AgP) and healthy gingival tissues, in order to explore the role of lncRNA in AgP. Methods: After the informed consents were obtained, gingival tissues from AgP patients (n=40) and healthy volunteers (n=40) were collected in Department of Periodontology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine (from Mar. 2012 to Aug. 2012) and Department of Periodontology, Hospital of Stomatology, Tianjin Medical University (from Oct. 2016 to Apr. 2017). The differential expression of lncRNA of tissues from AgP patients (n=20) and healthy volunteers (n=20) were examined via microarray assay. Bioinformatics was applied to analyze the expression data of lncRNA and correlative mRNA. Two lncRNAs (lncRNA-TNFRSF13C and lncRNA-API5) were chosen to verify the microarray results by using real time quantitative polymerase chain reaction (PCR) in the other gingival tissues. Results: Compared with the result of healthy gingival tissues, totally 8 632 lncRNAs were differentially expressed in tissues from AgP patients. From these data, 1 986 lncRNAs were significantly upregulated while 6 646 lncRNAs were downregulated, amongst which 48 lncRNAs were upregulated (>10 times) (P<0.05), 14 lncRNAs were downregulated (>10 times) (P<0.05). Furthermore, totally 5 519 correlative mRNAs were differentially expressed, amongst which 1 676 mRNAs were upregulated (≥2 times, P<0.05) and 3 843 mRNAs were downregulated≤0.5 (P<0.05). The selected lncRNA-TNFRSF13C and lncRNA-API5 were up-regulated in AgP (P<0.05), which confirmed the results of microarray. From bioinformatics, differential expression lncRNAs were in association with many signal pathways including toll-like receptor signaling pathway, cell cycle and apoptosis pathway, and tumor necrosis factor receptor superfamily pathway. Conclusions LncRNA may be involved in the pathogenesis of AgP through various pathways, which need to be further explored.