Tong Zhongchun, Wu Jie, Gong Qimei, Yuan Yifang, Wang Shengchao, Jiang Wenkai
Hospital of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China; Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China.
State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry & Endodontics, School of Stomatology, Fourth Military Medical University, No.145 Western Changle Road, Xi'an, Shaanxi 710032, China.
J Adv Res. 2024 Dec 12. doi: 10.1016/j.jare.2024.12.018.
Aging influences the regenerative and reparative functions of dental pulp, and an in-depth and complete understanding of aged dental pulp is highly important.
This study aimed to explore the heterogeneity of young and aged dental pulp tissue via single-cell RNA sequencing (scRNA-seq), search novel markers of aged dental pulp, and further explore their mechanism.
ScRNA-seq was employed to analyze the heterogeneity of young and aged dental pulp tissue, and immunohistochemical staining was used to detect new marker Insulin-like Growth Factor Binding Protein 7 (IGFBP7) in aged dental pulp. Differentially expressed genes (DEGs) between young and aged dental pulp tissue related with senescence-associated secretory phenotype (SASP) were validated in aging model of HO-induced dental pulp fibroblast (DPF). The effect of IGFBP7 on cellular senescence were validated by SA-β-Gal, γ-H2AX, and F-actin cytoskeletal staining. RNA-seq was used to analyze the mechanism of IGFBP7 alleviating senescence of HO-induced DPFs.
A total of 32,012 cells were sequenced from 8 dental pulp samples and categorized into 8 main clusters, including fibroblasts (FB), endothelial cells, monocytes, T cells, B cells, mesenchymal stem cells, Schwann cells, and nonmyelinating ScCs. The ratio of fibroblasts was the highest, and FB1 was the largest subcluster of fibroblasts in the young group. In aged dental pulp, the ratio of fibroblasts was relatively low, and fibroblasts had more cellular communication with other cell types in fibroblast growth factor (FGF) and insulin-like growth factor (IGF) signal pathways. IGFBP7 was significantly upregulated in the aged group. Recombinant IGFBP7 reduced the senescence of HO-induced DPFs.
These findings offer insights into the mechanisms of dental pulp aging and enhance our understanding of dental pulp at the single-cell level. Further comprehensive studies are required to clarify the exact mechanisms through which IGFBP7 influences dental pulp aging.
衰老会影响牙髓的再生和修复功能，因此深入全面地了解老年牙髓非常重要。
本研究旨在通过单细胞RNA测序（scRNA-seq）探索年轻和老年牙髓组织的异质性，寻找老年牙髓的新型标志物，并进一步探究其机制。
采用scRNA-seq分析年轻和老年牙髓组织的异质性，并用免疫组织化学染色检测老年牙髓中的新型标志物胰岛素样生长因子结合蛋白7（IGFBP7）。在过氧化氢诱导的牙髓成纤维细胞（DPF）衰老模型中验证年轻和老年牙髓组织中与衰老相关分泌表型（SASP）相关的差异表达基因（DEG）。通过SA-β-Gal、γ-H2AX和F-肌动蛋白细胞骨架染色验证IGFBP7对细胞衰老的影响。使用RNA-seq分析IGFBP7减轻过氧化氢诱导的DPF衰老的机制。
从8个牙髓样本中总共测序了32012个细胞，并分为8个主要簇，包括成纤维细胞（FB）、内皮细胞、单核细胞、T细胞、B细胞、间充质干细胞、雪旺细胞和无髓鞘雪旺细胞。成纤维细胞的比例最高，FB1是年轻组中最大的成纤维细胞亚簇。在老年牙髓中，成纤维细胞的比例相对较低，并且成纤维细胞在成纤维细胞生长因子（FGF）和胰岛素样生长因子（IGF）信号通路中与其他细胞类型有更多的细胞通讯。IGFBP7在老年组中显著上调。重组IGFBP7降低了过氧化氢诱导的DPF的衰老。
这些发现为牙髓衰老的机制提供了见解，并增强了我们在单细胞水平上对牙髓的理解。需要进一步的综合研究来阐明IGFBP7影响牙髓衰老的确切机制。
