Department of Pathogen Biology and Department of Laboratory Medicine, Wuhan No.1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Clin Exp Rheumatol. 2021 Mar-Apr;39 Suppl 129(2):13-20. doi: 10.55563/clinexprheumatol/6y0bjb. Epub 2021 Mar 9.
T cell immunoglobulin and mucin domain 3 (TIM-3) has been reported as an important regulatory molecule on T cells and plays a pivotal role in autoimmune diseases, but the impact on dendritic cells (DCs) is poorly explored. The formation of neutrophil extracellular traps (NETs) is considered as strongly implicated in the pathogenesis of autoimmune diseases, such as in myeloperoxidase-antineutrophil cytoplasmic autoantibody associated vasculitis (MPO-AAV). This study thus aimed to investigate the potential regulation roles of TIM-3 in the regulation of NETs-mediated DC activation in MPO-AAV.
Twenty untreated patients with MPO-AAV and 20 healthy controls were enrolled in this study. The expressions of TIM-3 and toll-like receptor 4 (TLR4) in peripheral blood dendritic cells were analysed by flow cytometry, and the release of NETs by neutrophils was evaluated by immunofluorescence. In animal experiments, we measured the DC activation markers after the stimulation of NETs. Furthermore, we detected the NETs-mediated DC activation after TIM-3 blockade.
Here we found an increased spontaneous NET production in MPOAAV patients. We also revealed a markedly reduced expression of TIM-3 and an increased expression of TLR4 on DCs of active MPO-AAV patients. We found the NETs could induce the activation of DCs and promote Toll-like receptor 4 expression on DC surface. More interestingly, the blockade of TIM-3 could further enhance the NETs-mediated DC cytokine expression.
Our results demonstrated DC surface TIM-3 plays an important role in maintaining the NETs mediated immune homeostasis in MPO-AAV, suggesting an important role in MPOAAV development.
T 细胞免疫球蛋白和粘蛋白结构域 3（TIM-3）已被报道为 T 细胞上的重要调节分子，在自身免疫性疾病中发挥关键作用，但对树突状细胞（DC）的影响尚未得到充分探索。中性粒细胞胞外诱捕网（NETs）的形成被认为与自身免疫性疾病的发病机制密切相关，如髓过氧化物酶-抗中性粒细胞胞质抗体相关性血管炎（MPO-AAV）。因此，本研究旨在探讨 TIM-3 在调节 MPO-AAV 中 NETs 介导的 DC 激活中的潜在调节作用。
本研究纳入了 20 例未经治疗的 MPO-AAV 患者和 20 名健康对照者。通过流式细胞术分析外周血树突状细胞中 TIM-3 和 Toll 样受体 4（TLR4）的表达，通过免疫荧光法评估中性粒细胞释放 NETs 的情况。在动物实验中，我们在 NETs 刺激后测量了 DC 激活标志物。此外，我们还检测了 TIM-3 阻断后 NETs 介导的 DC 激活。
我们发现 MPOAAV 患者中自发性 NETs 产生增加。我们还发现，活性 MPO-AAV 患者的 DC 上 TIM-3 表达明显降低，TLR4 表达增加。我们发现 NETs 可诱导 DC 激活，并促进 DC 表面 Toll 样受体 4 的表达。更有趣的是，TIM-3 阻断可进一步增强 NETs 介导的 DC 细胞因子表达。
我们的研究结果表明，DC 表面 TIM-3 在维持 MPO-AAV 中 NETs 介导的免疫平衡中发挥重要作用，提示其在 MPOAAV 发病机制中具有重要作用。
