Department of Orthodontics, Faculty of Medicine, Justus Liebig University Giessen, D-35392 Giessen, Germany.
Department of Periodontology, Faculty of Medicine, Justus Liebig University Giessen, D-35392 Giessen, Germany.
Int J Mol Sci. 2022 Jun 23;23(13):6977. doi: 10.3390/ijms23136977.
Patients with periodontitis undergoing orthodontic therapy may suffer from undesired dental root resorption. The purpose of this in vitro study was to investigate the molecular mechanisms resulting in PD-L1 expression of cementoblasts in response to infection with () peptidoglycan (PGN) and compressive force (CF), and its interaction with hypoxia-inducible factor (HIF)-1α molecule: The cementoblast (OCCM-30) cells were kinetically infected with various concentrations of PGN in the presence and absence of CF. Western blotting and RT-qPCR were performed to examine the protein expression of PD-L1 and HIF-1α as well as their gene expression. Immunofluorescence was applied to visualize the localization of these proteins within cells. An HIF-1α inhibitor was added for further investigation of necroptosis by flow cytometry analysis. Releases of soluble GAS-6 were measured by ELISA. PGN dose dependently stimulated PD-L1 upregulation in cementoblasts at protein and mRNA levels. CF combined with PGN had synergistic effects on the induction of PD-L1. Blockade of HIF-1α inhibited the PGN-inducible PD-L1 protein expression under compression, indicating an HIF-1α dependent regulation of PD-L1 induction. Concomitantly, an HIF-1α inhibitor decreased the GAS-6 release in the presence of CF and PGN co-stimulation. The data suggest that PGN of participates in PD-L1 up-regulation in cementoblasts. Additionally, the influence of compressive force on PGN-induced PD-L1 expression occurs in HIF-1α dependently. In this regard, HIF-1α may play roles in the immune response of cementoblasts via immune-inhibitory PD-L1. Our results underline the importance of molecular mechanisms involved in bacteria-induced periodontics and root resorption.
牙周炎患者在接受正畸治疗时可能会遭受非预期的牙根吸收。本体外研究旨在探讨导致成牙骨质细胞中 PD-L1 表达的分子机制，这些细胞受到感染（）肽聚糖（PGN）和压缩力（CF）的影响，以及其与缺氧诱导因子（HIF）-1α分子的相互作用：成牙骨质细胞（OCCM-30）细胞在存在和不存在 CF 的情况下，以不同浓度的动力学感染。Western blot 和 RT-qPCR 用于检测 PD-L1 和 HIF-1α的蛋白表达及其基因表达。免疫荧光用于可视化这些蛋白在细胞内的定位。加入 HIF-1α抑制剂，通过流式细胞术分析进一步研究坏死性凋亡。通过 ELISA 测量可溶性 GAS-6 的释放。PGN 剂量依赖性地刺激成牙骨质细胞中 PD-L1 在蛋白和 mRNA 水平上的上调。CF 与 PGN 联合对 PD-L1 的诱导具有协同作用。HIF-1α阻断抑制了在压缩下 PGN 诱导的 PD-L1 蛋白表达，表明 HIF-1α依赖性调节 PD-L1 诱导。同时，在 CF 和 PGN 共刺激存在的情况下，HIF-1α抑制剂降低了 GAS-6 的释放。数据表明，参与了成牙骨质细胞中 PD-L1 的上调。此外，CF 对 PGN 诱导的 PD-L1 表达的影响发生在 HIF-1α依赖性。在这方面，HIF-1α可能通过免疫抑制性 PD-L1 在成牙骨质细胞的免疫反应中发挥作用。我们的结果强调了涉及细菌诱导的牙周病和牙根吸收的分子机制的重要性。
