Department of Stomatology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China.
Int J Oral Sci. 2020 Jul 31;12(1):22. doi: 10.1038/s41368-020-00088-z.
A splicing mutation in VPS4B can cause dentin dysplasia type I (DD-I), a hereditary autosomal-dominant disorder characterized by rootless teeth, the etiology of which is genetically heterogeneous. In our study, dental follicle cells (DFCs) were isolated and cultured from a patient with DD-I and compared with those from an age-matched, healthy control. In a previous study, this DD-I patient was confirmed to have a loss-of-function splicing mutation in VPS4B (IVS7 + 46C > G). The results from this study showed that the isolated DFCs were vimentin-positive and CK14-negative, indicating that the isolated cells were derived from the mesenchyme. DFCs harboring the VPS4B mutation had a significantly higher proliferation rate from day 3 to day 8 than control DFCs, indicating that VPS4B is involved in cell proliferation. The cells were then replenished with osteogenic medium to investigate how the VPS4B mutation affected osteogenic differentiation. Induction of osteogenesis, detected by alizarin red and alkaline phosphatase staining in vitro, was decreased in the DFCs from the DD-I patient compared to the control DFCs. Furthermore, we also found that the VPS4B mutation in the DD-I patient downregulated the expression of osteoblast-related genes, such as ALP, BSP, OCN, RUNX2, and their encoded proteins. These outcomes confirmed that the DD-I-associated VPS4B mutation could decrease the capacity of DFCs to differentiate during the mineralization process and may also impair physiological root formation and bone remodeling. This might provide valuable insights and implications for exploring the pathological mechanisms underlying DD-I root development.
VPS4B 的剪接突变可导致牙本质发育不全 I 型 (DD-I)，这是一种遗传性常染色体显性疾病，其特征为无根牙，其病因具有遗传异质性。在我们的研究中，从患有 DD-I 的患者中分离并培养牙囊细胞 (DFC)，并将其与年龄匹配的健康对照进行比较。在之前的研究中，已证实该 DD-I 患者 VPS4B 存在无功能剪接突变 (IVS7 + 46C > G)。本研究结果表明，分离的 DFC 呈波形蛋白阳性且 CK14 阴性，表明分离的细胞来源于间充质。携带 VPS4B 突变的 DFC 从第 3 天到第 8 天的增殖率明显高于对照 DFC，表明 VPS4B 参与细胞增殖。然后用成骨培养基补充这些细胞，以研究 VPS4B 突变如何影响成骨分化。体外通过茜素红和碱性磷酸酶染色检测到成骨诱导，与对照 DFC 相比，DD-I 患者的 DFC 中减少。此外，我们还发现 DD-I 患者的 VPS4B 突变下调了成骨相关基因的表达，如 ALP、BSP、OCN、RUNX2 及其编码蛋白。这些结果证实，DD-I 相关的 VPS4B 突变可降低 DFC 在矿化过程中的分化能力，并且可能还会损害生理根形成和骨重塑。这可能为探索 DD-I 根发育的病理机制提供有价值的见解和启示。
