Monocytes and macrophages are major cellular components of the innate immunity that play essential roles in tissue homeostasis. The contribution of different subsets of monocytes/macrophages to periodontal health and disease has not been fully elucidated. Type 2 diabetes mellitus (T2DM) is a risk factor for periodontitis. We hypothesized that the monocyte/macrophage signaling is perturbed in periodontitis-affected sites versus periodontally healthy sites and that this perturbation plays a critical role in the pathogenesis of periodontitis. Pairs of gingival tissue samples (each from a periodontally healthy and a periodontitis-affected site of the same patient) were harvested from 27 periodontitis patients, with and without T2DM. Each sample was processed to form a single-cell suspension, and a flow-cytometry panel was designed and validated to study monocyte and macrophage phenotypes. In separate experiments, the transcriptional changes associated with a pro-inflammatory phenotype were also examined in monocyte/macrophage subsets obtained from peripheral blood of patients with T2DM versus diabetes-free controls. A significantly higher proportion of intermediate (CD14⁺CD16⁺) monocytes was observed in periodontitis-affected tissues compared to healthy tissues. These monocytes overexpressed HLA-DR and PDL1 molecules, suggesting their activated inflammatory status. PDL1 increase was specific to intermediate monocytes. The ratio of M1/M2 macrophages was also significantly higher in periodontally affected sites, signifying an imbalance between inflammatory and repair mechanisms. We found a significantly higher expression of PDL1 in overall monocytes and M1 macrophages in periodontitis-affected sites compared to controls. Importantly, we identified a subpopulation of M1 macrophages present in periodontally affected tissues which expressed high levels of CD47, a glycoprotein of the immunoglobulin family that plays a critical role in self-recognition and impairment of phagocytosis. Analysis of the transcriptional landscape of monocytes/macrophages in gingival tissue of T2DM patients with periodontitis revealed a significant disruption in homeostasis toward a proinflammatory phenotype, elevation of pro-inflammatory transcription factors STAT1 and IRF1, and repression of anti-inflammatory JMJD3 in circulating monocytes. Taken together, our results demonstrate disruption of myeloid-derived cell homeostasis in periodontitis, with or without T2DM, and highlight a potentially significant role of these cell types in its pathogenesis. The impact of macrophage and monocyte signaling pathways on the pathobiology of periodontitis should be further evaluated.

单核细胞和巨噬细胞是先天免疫的主要细胞成分，在组织稳态中起重要作用。单核细胞/巨噬细胞的不同亚群对牙周健康和疾病的贡献尚未完全阐明。2型糖尿病（T2DM）是牙周炎的危险因素。我们假设单核细胞/巨噬细胞信号在受牙周炎影响的部位与牙周健康部位受到干扰，并且这种干扰在牙周炎的发病机制中起关键作用。从 27 名患有和未患有 T2DM 的牙周炎患者身上采集了一对牙龈组织样本（每个样本来自同一患者的牙周健康部位和牙周炎受累部位）。每个样品都经过处理形成单细胞悬液，并且设计并验证了流式细胞仪面板来研究单核细胞和巨噬细胞表型。在单独的实验中，还检查了从 T2DM 患者与无糖尿病对照组的外周血中获得的单核细胞/巨噬细胞亚群中与促炎表型相关的转录变化。中间体（CD14⁺ CD16 ⁺) 与健康组织相比，在受牙周炎影响的组织中观察到单核细胞。这些单核细胞过表达 HLA-DR 和 PDL1 分子，表明它们处于激活的炎症状态。PDL1 增加是特定于中间单核细胞。M1/M2巨噬细胞的比例在牙周受累部位也显着升高，表明炎症和修复机制之间存在不平衡。与对照组相比，我们发现牙周炎影响部位的整体单核细胞和 M1 巨噬细胞中 PDL1 的表达显着更高。重要的是，我们确定了存在于牙周受累组织中的 M1 巨噬细胞亚群，其表达高水平的 CD47，这是一种免疫球蛋白家族的糖蛋白，在自我识别和吞噬功能受损中起关键作用。对患有牙周炎的 2 型糖尿病患者牙龈组织中单核细胞/巨噬细胞转录情况的分析显示，促炎表型的稳态显着破坏，促炎转录因子 STAT1 和 IRF1 升高，循环单核细胞中的抗炎 JMJD3 受到抑制。总之，我们的研究结果表明，无论有无 T2DM，牙周炎中髓源性细胞稳态的破坏，并强调了这些细胞类型在其发病机制中的潜在重要作用。应进一步评估巨噬细胞和单核细胞信号通路对牙周炎病理生物学的影响。促炎转录因子 STAT1 和 IRF1 的升高，以及循环单核细胞中抗炎 JMJD3 的抑制。总之，我们的研究结果表明，无论有无 T2DM，牙周炎中髓源性细胞稳态的破坏，并强调了这些细胞类型在其发病机制中的潜在重要作用。应进一步评估巨噬细胞和单核细胞信号通路对牙周炎病理生物学的影响。促炎转录因子 STAT1 和 IRF1 的升高，以及循环单核细胞中抗炎 JMJD3 的抑制。总之，我们的研究结果表明，无论有无 T2DM，牙周炎中髓源性细胞稳态的破坏，并强调了这些细胞类型在其发病机制中的潜在重要作用。应进一步评估巨噬细胞和单核细胞信号通路对牙周炎病理生物学的影响。