Løvschall H, Tummers M, Thesleff I, Füchtbauer E-M, Poulsen K
Department of Dental Pathology, Operative Dentistry and Endodontics, Royal Dental College, Faculty of Health Sciences, University of Aarhus, Denmark.
Eur J Oral Sci. 2005 Aug;113(4):312-7. doi: 10.1111/j.1600-0722.2005.00221.x.
Notch signaling is an evolutionarily conserved pathway that controls the developmental choices made by individual cells. Cells communicate via Notch receptors and their ligands, which direct decisions on the fate of stem cells according to the states of their neighbors. In this study we explored Notch signaling after the pulp capping of adult first upper rat molars. The wound was capped with calcium hydroxide. In situ hybridization revealed an increased expression of Notch signaling genes on day 1, which showed a tendency to decrease on day 3. Notch1 increased in the subodontoblast zone and close to the lesion limited to a few cells. Notch2 increased in pulp stroma surrounded by coronal odontoblasts. Notch1 and, especially, Notch3 expression increased, corresponding to perivascular cell groups. A low increase of ligand expression was observed near the injury with Delta1 expression along the dentin wall and Jagged1 in the stroma. Expression of the downstream target, Hes1, was observed along the lesion and adjacent dentin walls. Hes5 expression was not observed. The results indicate that Notch signaling is activated in response to injury and associated with the differentiation of pulp cells into perivascular cells and odontoblasts. The findings are consistent with the concept that the Notch pathway controls stem cell fate during pulp regeneration.
Notch信号通路是一条在进化上保守的通路，它控制着单个细胞所做出的发育选择。细胞通过Notch受体及其配体进行通讯，这些受体和配体根据其相邻细胞的状态来指导干细胞命运的决定。在本研究中，我们探究了成年大鼠上颌第一磨牙盖髓术后的Notch信号通路。伤口用氢氧化钙覆盖。原位杂交显示，Notch信号基因在第1天表达增加，在第3天呈下降趋势。Notch1在成牙本质细胞下层区域以及局限于少数细胞的靠近损伤处增加。Notch2在冠部成牙本质细胞包围的牙髓基质中增加。Notch1，尤其是Notch3的表达增加，与血管周围细胞群相对应。在损伤附近观察到配体表达有少量增加，Delta1沿着牙本质壁表达而Jagged1在基质中表达。在损伤处及相邻的牙本质壁观察到下游靶点Hes1的表达。未观察到Hes5的表达。结果表明，Notch信号通路在损伤反应中被激活，并与牙髓细胞向血管周围细胞和成牙本质细胞的分化相关。这些发现与Notch通路在牙髓再生过程中控制干细胞命运的概念一致。
