Zhou Linxi, Fan Mingyue, Xia Lunguo, Chen Yuntian, Han Xiaozhe, Fang Bing
Department of Orthodontics, College of Stomatology, Shanghai Jiao Tong University School of Medicine Affiliated Ninth People's Hospital, Shanghai, China.
National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China.
J Transl Int Med. 2025 Jul 24;13(4):338-348. doi: 10.1515/jtim-2025-0038. eCollection 2025 Aug.
Periodontitis is a chronic multifactorial inflammatory disease caused by the excessive host immune response to bacterial infection, leading to periodontal tissue destruction. Owing to their plasticity, macrophages are key players in this process, and B10 cells, with their immunosuppressive efects, are vital for periodontal immunity. We propose that, in periodontitis, B10 cells transmit immunosuppressive signals programmed cell death ligand-1 (PD-L1) /programmed cell death protein 1 (PD-1) signalling, stimulating macrophage diferentiation, alleviating inflammation, restoring homeostasis, and reducing alveolar bone resorption. The aim of this study was to investigate the efect of B10 cells on the polarization of macrophages in the context of periodontitis and the related molecular mechanism.
B10 cells were cocultured with RAW264.7 cells in the presence or absence of a Transwell insert. The M2 macrophage proportion and PD-1 expression in macrophages were assessed by flow cytometry and quantitative polymerase chain reaction (qPCR). PD-L1 knockout (KO) B10 cells and wild-type B10 cells were subsequently cocultured with macrophages separately. For experiments, we injected phosphate-buffered saline (PBS), B10 cells, or PD-L1 KO B10 cells into periodontitis model mice. We evaluated outcomes microcomputed tomography, histological analysis, and tartrate-resistant acid phosphatase (TRAP) staining and measured the messenger ribonucleic acid (mRNA) expression levels of tumor necrosis factor-α (TNF-α), receptor activator of nuclear factor kappa-B ligand (RANKL), interferon-γ (IFN-γ), interleukin 10 (IL-10), and osteoprotegerin (OPG) in gingival tissue surrounding the maxillary second molar qPCR.
Compared with the indirect coculture, the direct coculture of macrophages with B10 cells led to a greater proportion of M2 macrophages and increased PD-1 expression levels in macrophages. Coculturing macrophages with PD-L1 KO B10 cells confirmed that B10 cells induced the M2 polarization of macrophages and upregulated PD-L1 expression in macrophages PD-L1/PD-1 signalling. Compared with the groups injected with PBS or PD-L1 KO B10 cells, the B10 cell group exhibited significant decreases in local inflammatory factor levels, alveolar bone resorption, and the number of bone-resorbed cells within the alveolar bone area .
B10 cells can regulate macrophage polarization the PD-L1/PD-1 signalling pathway, thereby suppressing the inflammatory response and reducing alveolar bone resorption during periodontitis. This novel concept can guide future treatment strategies for periodontitis.
牙周炎是一种由宿主对细菌感染的过度免疫反应引起的慢性多因素炎症性疾病，会导致牙周组织破坏。巨噬细胞因其可塑性而在这一过程中发挥关键作用，而具有免疫抑制作用的B10细胞对牙周免疫至关重要。我们提出，在牙周炎中，B10细胞通过程序性细胞死亡配体-1（PD-L1）/程序性细胞死亡蛋白1（PD-1）信号传导传递免疫抑制信号，刺激巨噬细胞分化，减轻炎症，恢复内环境稳态，并减少牙槽骨吸收。本研究的目的是探讨在牙周炎背景下B10细胞对巨噬细胞极化的影响及其相关分子机制。
将B10细胞与RAW264.7细胞在有或无Transwell小室的情况下共培养。通过流式细胞术和定量聚合酶链反应（qPCR）评估巨噬细胞中M2巨噬细胞比例和PD-1表达。随后将PD-L1基因敲除（KO）的B10细胞和野生型B10细胞分别与巨噬细胞共培养。在实验中，我们将磷酸盐缓冲盐水（PBS）、B10细胞或PD-L1 KO B10细胞注射到牙周炎模型小鼠体内。我们通过微型计算机断层扫描、组织学分析和抗酒石酸酸性磷酸酶（TRAP）染色评估结果，并通过qPCR测量上颌第二磨牙周围牙龈组织中肿瘤坏死因子-α（TNF-α）、核因子κB受体活化因子配体（RANKL）、干扰素-γ（IFN-γ）、白细胞介素10（IL-10）和骨保护素（OPG）的信使核糖核酸（mRNA）表达水平。
与间接共培养相比，巨噬细胞与B10细胞直接共培养导致M2巨噬细胞比例更高，且巨噬细胞中PD-1表达水平增加。将巨噬细胞与PD-L1 KO B10细胞共培养证实，B10细胞通过PD-L1/PD-1信号传导诱导巨噬细胞向M2极化并上调巨噬细胞中PD-L1表达。与注射PBS或PD-L1 KO B10细胞的组相比，B10细胞组的局部炎症因子水平、牙槽骨吸收以及牙槽骨区域内骨吸收细胞数量均显著降低。
B10细胞可通过PD-L1/PD-1信号通路调节巨噬细胞极化，从而在牙周炎期间抑制炎症反应并减少牙槽骨吸收。这一新概念可为未来牙周炎的治疗策略提供指导。
