Wang Luxu, Liu Ting, Zhang Weidong, Liu Hongrui, Qi Yuping, Li Minqi
School of Stomatology, Jinzhou Medical University, Jinzhou, China.
Department of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Jinan, China.
J Periodontol. 2025 Apr 21. doi: 10.1002/JPER.24-0497.
One strategy to delay bone loss in periodontitis involves maintaining the osteogenic differentiation function of periodontal ligament stem cells (PDLSCs). The core circadian gene BMAL1 influences the fate of mesenchymal stem cells and is essential for regulating pyroptosis, apoptosis, and necroptosis. PANoptosis, a novel form of programmed cell death, simultaneously activates all 3 pathways. This study focuses on the role of BMAL1, the process of PANoptosis, and the osteogenic impairment of PDLSCs.
A mouse periodontitis model was established to evaluate the expression of BMAL1 and osteogenic factors. We stimulated PDLSCs with lipopolysaccharide (LPS) and used a Western blot to detect PANoptosis-related factors. Osteogenic factors in PDLSCs were assessed using real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, alkaline phosphatase, and alizarin red staining. The expression of ERK pathway proteins was examined by immunofluorescence and Western blot to investigate how BMAL1 regulates PANoptosis under inflammatory conditions.
Treatment with LPS leads to the downregulation of BMAL1 expression, which subsequently induces RIPK1-PANoptosome-mediated PANoptosis in PDLSCs, impairing their osteogenic differentiation function. Inhibition of the RIPK1-PANoptosome with Nec-1S improved the expression of osteogenic differentiation-related genes and proteins. Overexpression of BMAL1 using the synthetic ligand SR1078 alleviated these detrimental effects. Inhibition of the ERK pathway with U0126 reduced the expression of its downstream target AP-1, effectively reversing the impact of BMAL1 on PANoptosis.
The downregulation of BMAL1 triggers PANoptosis in PDLSCs, leading to impaired osteogenic function under inflammatory conditions. This study provides new insights into the pathogenesis of periodontitis and suggests novel targets for its prevention and treatment.
Periodontitis is a chronic inflammatory condition of the oral cavity marked by the destruction of periodontal attachment and resorption of alveolar bone. One strategy to delay alveolar bone loss in periodontitis involves maintaining the osteogenic differentiation function of periodontal ligament stem cells (PDLSCs). The circadian rhythm influences the fate of mesenchymal stem cells, with the core circadian gene BMAL1 playing a crucial role in regulating pyroptosis, apoptosis, and necroptosis. PANoptosis is a novel form of programmed cell death, encompassing pyroptosis, apoptosis, and necroptosis, which may play a role in regulating the osteogenic activity of PDLSCs. Our study aims to detect the role of PANoptosis of PDLSCs in periodontitis and elucidate the underlying relationship between BMAL1 and PANoptosis. We found that treatment with lipopolysaccharide leads to the downregulation of BMAL1 expression, which subsequently induces RIPK1-PANoptosome-mediated PANoptosis in PDLSCs, impairing their osteogenic differentiation function. Notably, inhibition of the RIPK1-PANoptosome improved the expression of osteogenic differentiation-related genes and proteins. Mechanistic exploration revealed that BMAL1 downregulation induces PANoptosis in PDLSCs through the ERK/AP-1 signaling pathway. This study highlights the potential therapeutic targets for mitigating bone loss in periodontitis.
延缓牙周炎骨质流失的一种策略是维持牙周膜干细胞（PDLSCs）的成骨分化功能。核心昼夜节律基因BMAL1影响间充质干细胞的命运，并且对于调节细胞焦亡、凋亡和坏死性凋亡至关重要。PAN凋亡是一种新型程序性细胞死亡形式，可同时激活所有这三种途径。本研究聚焦于BMAL1的作用、PAN凋亡过程以及PDLSCs的成骨损伤。
建立小鼠牙周炎模型以评估BMAL1和成骨因子的表达。我们用脂多糖（LPS）刺激PDLSCs，并使用蛋白质免疫印迹法检测PAN凋亡相关因子。通过实时定量聚合酶链反应（RT-qPCR）、蛋白质免疫印迹法、碱性磷酸酶和茜素红染色评估PDLSCs中的成骨因子。通过免疫荧光和蛋白质免疫印迹法检测ERK通路蛋白的表达，以研究BMAL1在炎症条件下如何调节PAN凋亡。
LPS处理导致BMAL1表达下调，随后诱导PDLSCs中RIPK1-PAN凋亡小体介导的PAN凋亡，损害其成骨分化功能。用Nec-1S抑制RIPK1-PAN凋亡小体可改善成骨分化相关基因和蛋白质的表达。使用合成配体SR1078过表达BMAL1可减轻这些有害影响。用U0126抑制ERK通路可降低其下游靶点AP-1的表达，有效逆转BMAL1对PAN凋亡的影响。
BMAL1的下调触发PDLSCs中的PAN凋亡，导致炎症条件下成骨功能受损。本研究为牙周炎的发病机制提供了新见解，并提出了其预防和治疗的新靶点。
牙周炎是一种口腔慢性炎症性疾病，其特征是牙周附着破坏和牙槽骨吸收。延缓牙周炎牙槽骨流失的一种策略是维持牙周膜干细胞（PDLSCs）的成骨分化功能。昼夜节律影响间充质干细胞的命运，核心昼夜节律基因BMAL1在调节细胞焦亡、凋亡和坏死性凋亡中起关键作用。PAN凋亡是一种新型程序性细胞死亡形式，包括细胞焦亡、凋亡和坏死性凋亡，可能在调节PDLSCs的成骨活性中发挥作用。我们的研究旨在检测PDLSCs的PAN凋亡在牙周炎中的作用，并阐明BMAL1与PAN凋亡之间的潜在关系。我们发现脂多糖处理导致BMAL1表达下调，随后诱导PDLSCs中RIPK1-PAN凋亡小体介导的PAN凋亡，损害其成骨分化功能。值得注意的是，抑制RIPK1-PAN凋亡小体可改善成骨分化相关基因和蛋白质的表达。机制探索表明，BMAL1下调通过ERK/AP-1信号通路诱导PDLSCs中的PAN凋亡。本研究突出了减轻牙周炎骨质流失的潜在治疗靶点。
