Liu Jiayi, Tian Haoyang, Ju Jinhong, Nie Fujiao, Yin Qiuyue, Zhao Jingjing, Wang Suli, Guo Hongmei, Yang Pishan
Department of Periodontology, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, Jinan, Shandong, China.
J Periodontal Res. 2024 Dec 12. doi: 10.1111/jre.13372.
To investigate whether trained immunity occurs in gingival fibroblasts (GFs) and its relationship to the persistence of inflammation in periodontitis.
Periodontally healthy and inflammatory gingival fibroblasts (HGFs and IGFs) were cultured through continuous adherence subculture of tissue blocks. Trained immunity in HGFs was evaluated via a classic in vitro model, with relevant markers assessed via enzyme-linked immunosorbent assay, lactate content assay, glycolytic rate assay, and chromatin immunoprecipitation. A histone methyltransferase blocker and a PI3K inhibitor were added to investigate the mechanisms underlying trained immunity. The relationship between trained immunity and periodontitis was further examined via immunofluorescence staining and chromatin immunoprecipitation on IGFs.
Compared with untrained cells, GFs trained with Porphyromonas gingivalis-lipopolysaccharide (P. gingivalis-LPS) exhibited a significant increase in IL-6 and TNF-α secretion, enhanced glycolytic metabolism, and enriched mono-methylation of lysine 4 on histone H3 (H3K4me1) at the enhancer regions of TNF-α and IL-6. The addition of a histone methyltransferase blocker and a PI3K inhibitor greatly reduced trained immunity. Additionally, the response of IGFs to P. gingivalis-LPS stimulation and their epigenetic modifications were similar to those observed in trained HGFs.
This study novelly discovered that both P. gingivalis-LPS-stimulated HGFs and IGFs in periodontitis acquired trained immunity. Following P. gingivalis-LPS stimulation, HGFs underwent metabolic and epigenetic changes via the PI3K/AKT pathway, with these epigenetic changes also observed in IGFs. This finding suggests that trained immunity in GFs may be a key mechanism underlying the recurrence and persistence of periodontitis.
研究牙龈成纤维细胞（GFs）中是否存在训练免疫及其与牙周炎炎症持续存在的关系。
通过组织块连续贴壁传代培养牙周健康和炎症牙龈成纤维细胞（HGFs和IGFs）。通过经典体外模型评估HGFs中的训练免疫，通过酶联免疫吸附测定、乳酸含量测定、糖酵解速率测定和染色质免疫沉淀评估相关标志物。添加组蛋白甲基转移酶阻滞剂和PI3K抑制剂以研究训练免疫的潜在机制。通过对IGFs进行免疫荧光染色和染色质免疫沉淀进一步研究训练免疫与牙周炎的关系。
与未训练的细胞相比，用牙龈卟啉单胞菌脂多糖（P. gingivalis-LPS）训练的GFs表现出IL-6和TNF-α分泌显著增加、糖酵解代谢增强以及TNF-α和IL-6增强子区域组蛋白H3赖氨酸4单甲基化（H3K4me1）富集。添加组蛋白甲基转移酶阻滞剂和PI3K抑制剂大大降低了训练免疫。此外，IGFs对P. gingivalis-LPS刺激的反应及其表观遗传修饰与训练的HGFs中观察到的相似。
本研究首次发现牙周炎中P. gingivalis-LPS刺激的HGFs和IGFs均获得了训练免疫。在P. gingivalis-LPS刺激后，HGFs通过PI3K/AKT途径发生代谢和表观遗传变化，IGFs中也观察到这些表观遗传变化。这一发现表明GFs中的训练免疫可能是牙周炎复发和持续存在的关键机制。
