Pan Yuhua, Lu Ting, Peng Ling, Zeng Qi, Huang Xiangyu, Yao Xinchen, Wu Buling, Xiong Fu
Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
Department of Pediatric Dentistry, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China.
Stem Cells Int. 2021 Sep 9;2021:7653013. doi: 10.1155/2021/7653013. eCollection 2021.
Mutations of the Ectodysplasin-A (EDA) gene are generally associated with syndrome hypohidrotic ectodermal dysplasia or nonsyndromic tooth agenesis. The influence of EDA mutations on dentinogenesis and odontoblast differentiation has not been reported. The aim of this study was to identify genetic clues for the causes of familial nonsyndromic oligodontia and explore the underlying mechanisms involved, while focusing on the role of human dental pulp stem cells (hDPSCs).
Candidate gene sequences were obtained by PCR amplification and Sanger sequencing. Functional analysis was conducted, and the pathogenesis associated with mutations in hDPSCs was investigated to explore the impact of the identified mutation on the phenotype. Capillary electrophoresis (CE) was used to detect X-chromosome inactivation (XCI) in the blood of female carriers.
In this study, we identified an mutation in a Chinese family: the missense mutation c.1013C>T (Thr338Met). Transfection of hDPSCs with a mutant lentivirus decreased the expression of EDA and dentin sialophosphoprotein (DSPP) compared with transfection of control EDA lentivirus. Mechanistically, mutant EDA inhibited the activation of the NF-B pathway. The CE results showed that symptomatic female carriers had a skewed XCI with a preferential inactivation of the X chromosome that carried the normal allele.
In summary, we demonstrated that mutations result in nonsyndromic tooth agenesis in heterozygous females and that, mechanistically, EDA regulates odontogenesis through the NF-B signalling pathway in hDPSCs. Due to the large heterogeneity of tooth agenesis, this study provided a genetic basis for individuals who exhibit similar clinical phenotypes.
外胚层发育不良蛋白 A（EDA）基因突变通常与综合征性少汗性外胚层发育不良或非综合征性牙齿缺失有关。EDA 突变对牙本质生成和成牙本质细胞分化的影响尚未见报道。本研究旨在确定家族性非综合征性少牙症病因的遗传线索，并探讨其潜在机制，同时关注人牙髓干细胞（hDPSCs）的作用。
通过 PCR 扩增和桑格测序获得候选基因序列。进行功能分析，研究与 hDPSCs 突变相关的发病机制，以探讨所鉴定突变对表型的影响。采用毛细管电泳（CE）检测女性携带者血液中的 X 染色体失活（XCI）。
在本研究中，我们在一个中国家系中鉴定出一个突变：错义突变 c.1013C>T（Thr338Met）。与转染对照 EDA 慢病毒相比，用突变型慢病毒转染 hDPSCs 可降低 EDA 和牙本质涎磷蛋白（DSPP）的表达。机制上，突变型 EDA 抑制 NF-κB 通路的激活。CE 结果显示，有症状的女性携带者存在 XCI 偏斜，携带正常等位基因的 X 染色体优先失活。
总之，我们证明了 EDA 突变导致杂合子女性出现非综合征性牙齿缺失，并且从机制上讲，EDA 通过 hDPSCs 中的 NF-κB 信号通路调节牙发育。由于牙齿缺失的高度异质性，本研究为表现出相似临床表型的个体提供了遗传基础。
