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 中的剪接突变可导致 I 型牙本质发育不良 (DD-I)，这是一种以无根牙为特征的遗传性常染色体显性遗传疾病，其病因具有遗传异质性。在我们的研究中，牙囊细胞 (DFC) 从 DD-I 患者中分离和培养，并与年龄匹配的健康对照者进行比较。在之前的一项研究中，该 DD-I 患者被证实在VPS4B 中存在功能丧失剪接突变（IVS7 + 46C > G）。这项研究的结果表明，分离的 DFC 为波形蛋白阳性和 CK14 阴性，表明分离的细胞来自间充质。包含 VPS4B 的DFC从第 3 天到第 8 天，突变的增殖率显着高于对照 DFC，表明VPS4B参与细胞增殖。然后用成骨培养基补充细胞以研究VPS4B突变如何影响成骨分化。与对照 DFC 相比，DD-1 患者的 DFC 中通过茜素红和碱性磷酸酶染色检测到的成骨诱导降低。此外，我们还发现DD-1患者的VPS4B突变下调了成骨细胞相关基因的表达，如ALP、BSP、OCN、RUNX2，以及它们编码的蛋白质。这些结果证实，DD-I 相关的VPS4B突变会降低 DFC 在矿化过程中的分化能力，也可能会损害生理根的形成和骨重塑。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意义。