Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
Department of Periodontology, School of Dentistry, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan.
J Periodontol. 2024 Aug;95(8):764-777. doi: 10.1002/JPER.23-0561. Epub 2024 Mar 25.
This study aimed to investigate the contribution of myeloid differentiation primary-response gene 88 (MyD88) on the differentiation of T helper type 17 (Th17) and regulatory T (Treg) cells and the emerging subgingival microbiota dysbiosis in Porphyromonas gingivalis-induced experimental periodontitis.
Alveolar bone loss, infiltrated inflammatory cells, immunostained cells for tartrate-resistant acid phosphatase (TRAP), the receptor activator of nuclear factor-kB ligand (RANKL), and osteoprotegerin (OPG) were quantified by microcomputerized tomography and histological staining between age- and sex-matched homozygous littermates (wild-type [WT, Myd88] and Myd88 on C57BL/6 background). The frequencies of Th17 and Treg cells in cervical lymph nodes (CLNs) and spleen were determined by flow cytometry. Cytokine expression in gingival tissues, CLNs, and spleens were studied by quantitative polymerase chain reaction (qPCR). Analysis of the composition of the subgingival microbiome and functional annotation of prokaryotic taxa (FAPROTAX) analysis were performed.
P. gingivalis-infected Myd88 mice showed alleviated bone loss, TRAP osteoclasts, and RANKL/OPG ratio compared to WT mice. A significantly higher percentage of Foxp3CD4 T cells in infected Myd88 CLNs and a higher frequency of RORγtCD4 T cells in infected WT mice was noted. Increased IL-10 and IL-17a expressions in gingival tissue at D14-D28 then declined in WT mice, whereas an opposite pattern was observed in Myd88 mice. The Myd88 mice exhibited characteristic increases in gram-positive species and species having probiotic properties, while gram-negative, anaerobic species were noted in WT mice. FAPROTAX analysis revealed increased aerobic chemoheterotrophy in Myd88 mice, whereas anaerobic chemoheterotrophy was noted in WT mice after P. gingivalis infection.
MyD88 plays an important role in inflammation-induced bone loss by modulating the dynamic equilibrium between Th17/Treg cells and dysbiosis in P. gingivalis-induced experimental periodontitis.
本研究旨在探讨髓样分化初级反应基因 88（MyD88）在辅助性 T 细胞 17（Th17）和调节性 T（Treg）细胞分化以及牙龈卟啉单胞菌诱导的实验性牙周炎中新兴的龈下微生物群落失调中的作用。
通过微计算机断层扫描和组织学染色，在年龄和性别匹配的纯合子同窝仔鼠（野生型[WT，Myd88]和 C57BL/6 背景下的 Myd88）之间量化牙槽骨丧失、浸润的炎性细胞、抗酒石酸酸性磷酸酶（TRAP）免疫染色细胞、核因子-kB 配体受体激活剂（RANKL）和骨保护素（OPG）。通过流式细胞术测定颈淋巴结（CLN）和脾中 Th17 和 Treg 细胞的频率。通过定量聚合酶链反应（qPCR）研究牙龈组织、CLN 和脾中的细胞因子表达。进行龈下微生物组的组成分析和原核分类群的功能注释（FAPROTAX）分析。
与 WT 小鼠相比，牙龈卟啉单胞菌感染的 Myd88 小鼠显示出减轻的骨损失、TRAP 破骨细胞和 RANKL/OPG 比值。在感染的 Myd88 CLN 中，Foxp3CD4 T 细胞的百分比显著增加，而在感染的 WT 小鼠中，RORγtCD4 T 细胞的频率更高。WT 小鼠在第 14-28 天牙龈组织中 IL-10 和 IL-17a 的表达增加，然后下降，而 Myd88 小鼠则呈现相反的模式。Myd88 小鼠表现出革兰氏阳性物种和具有益生菌特性的物种的特征性增加，而 WT 小鼠则出现革兰氏阴性、厌氧物种。FAPROTAX 分析显示，Myd88 小鼠在牙龈卟啉单胞菌感染后表现出需氧化能异养作用增加，而 WT 小鼠则表现出厌氧化能异养作用增加。
MyD88 通过调节 Th17/Treg 细胞之间的动态平衡和牙龈卟啉单胞菌诱导的实验性牙周炎中的菌群失调，在炎症诱导的骨丢失中发挥重要作用。
