Located at the interface of the dentin–pulp complex, the odontoblasts are specialized cells responsible for dentin synthesis and nociceptive signal detection in response to external stimuli. Recent studies have shown that the mechanosensitive ion channel PIEZO1 is involved in bone formation and remodeling through the influx of calcium ions, and it is abundantly expressed in odontoblasts. However, the specific role of PIEZO1 in reactionary dentinogenesis and the underlying mechanisms remain elusive. In this study, we found intense PIEZO1 expression in the plasma membrane and cytoplasm of odontoblasts in healthy human third molars, mouse mandibular molars, and human odontoblast-like cells (hOBLCs). In hOBLCs, PIEZO1 positively regulated DSPP, DMP1, and COL1A1 expression through the Ca2+/PI3K-Akt/SEMA3A signaling pathway. In addition, exogenous SEMA3A supplementation effectively reversed reduced mineralization capacity in PIEZO1-knockdown hOBLCs. In vivo, Piezo1 expression peaked at day 7 and returned to baseline at day 21 in a wild-type mice dentin injury model, with Sema3a presenting a similar expression pattern. To investigate the specific role of PIEZO1 in odontoblast-mediated reactionary dentinogenesis, mice with a conditional knockout of Piezo1 in odontoblasts were generated, and no significant differences in teeth phenotypes were observed between the control and conditional knockout ( cKO) mice. Nevertheless, cKO mice exhibited reduced reactionary dentin formation and decreased Sema3a and Dsp positive staining after dentin injury, indicating impaired dental pulp repair by odontoblasts. In summary, these findings suggest that PIEZO1 enhances the mineralization capacity of hOBLCs in vitro via the Ca2+/PI3K-Akt/SEMA3A signaling pathway and contributes to reactionary dentinogenesis in vivo.

中文翻译：

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PIEZO1 通过 SEMA3A 促进成牙本质细胞介导的反应性牙本质发生


成牙本质细胞位于牙本质-牙髓复合体的界面，是负责牙本质合成和响应外部刺激的伤害性信号检测的特殊细胞。最近的研究表明，机械敏感离子通道PIEZO1通过钙离子的流入参与骨形成和重塑，并且在成牙本质细胞中大量表达。然而，PIEZO1 在反动牙本质发生中的具体作用及其潜在机制仍不清楚。在这项研究中，我们发现健康人第三磨牙、小鼠下颌磨牙和人成牙本质细胞样细胞（hOBLC）的质膜和成牙本质细胞细胞质中强烈表达PIEZO1。在 hOBLC 中，PIEZO1 通过 Ca2+/PI3K-Akt/SEMA3A 信号通路正向调节 DSPP、DMP1 和 COL1A1 的表达。此外，外源性SEMA3A补充剂有效逆转了PIEZO1敲低hOBLC矿化能力的降低。在体内，在野生型小鼠牙本质损伤模型中，Piezo1 表达在第 7 天达到峰值，并在第 21 天恢复到基线，Sema3a 呈现出类似的表达模式。为了研究PIEZO1在成牙本质细胞介导的反应性牙本质发生中的具体作用，产生了在成牙本质细胞中条件性敲除Piezo1的小鼠，并且在对照和条件敲除（cKO）小鼠之间没有观察到牙齿表型的显着差异。然而，cKO小鼠在牙本质损伤后表现出反应性牙本质形成减少以及Sema3a和Dsp阳性染色减少，表明成牙本质细胞的牙髓修复受损。 总之，这些研究结果表明，PIEZO1 通过 Ca2+/PI3K-Akt/SEMA3A 信号通路增强 hOBLC 的体外矿化能力，并有助于体内反应性牙本质形成。