Cancer and Inflammation Program, Frederick National Laboratory for Cancer Research, Center for Cancer Research, National Cancer Institute, Frederick, MD, United States.
Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research sponsored by the National Cancer Institute, National Institutes of Health, Bethesda, MD, United States.
Front Immunol. 2018 Dec 18;9:2982. doi: 10.3389/fimmu.2018.02982. eCollection 2018.
High mobility group nucleosome-binding protein 1 (HMGN1 or N1) is a Th1-polarizing alarmin, but alone is insufficient to induce antitumor immunity. We previously showed that combination of N1 and R848, a synthetic TLR7/8 agonist, synergistically activates dendritic cells (DCs) and induces therapeutic antitumor immunity, however, it remained unclear how N1 and R848 synergistically activate DCs. Here, we show that co-stimulation with N1 and R848 of human monocyte-derived DCs (MoDCs) markedly upregulated DC's surface expression of CD80, CD83, CD86, and HLA-DR, as well as synergistic production of pro-inflammatory cytokines including IL-12p70, IL-1β, and TNF-α. This combination also synergistically activated NF-κB and multiple MAPKs that are involved in DC maturation. Moreover, N1 and R848 synergistically increased nuclear translocation of interferon (IFN) regulatory transcription factors (e.g., IRF3 and IRF7) and promoted the expression of type 1 IFNs such as IFN-α2, IFN-α4, and IFN-β1. Similar signaling pathways were also induced in mouse bone marrow-derived DCs (BMDCs). RNA-seq analysis in human MoDCs revealed that N1 plus R848 synergistically upregulated the expression of genes predominantly involved in DC maturation pathway, particularly genes critical for the polarization of Th1 immune responses (e.g., , and , etc.). Overall, our findings show that (1) N1 synergizes with R848 in activating human and mouse DCs and (2) the synergistic effect based on various intracellular signaling events culminated in the activation of multiple transcriptional factors. These findings have important implications for future clinical trials since N1 and R848 synergistically promoted optimal Th1 lineage immune responses resulting in tumor rejection in mice.
高迁移率族蛋白 N1（HMGN1 或 N1）是一种 Th1 极化警报素，但单独使用不足以诱导抗肿瘤免疫。我们之前的研究表明，N1 与 R848（一种合成的 TLR7/8 激动剂）联合使用可协同激活树突状细胞（DC）并诱导治疗性抗肿瘤免疫，但 N1 和 R848 如何协同激活 DC 仍不清楚。在这里，我们表明，N1 和 R848 共同刺激人单核细胞衍生的树突状细胞（MoDC）可显著上调 DC 表面 CD80、CD83、CD86 和 HLA-DR 的表达，以及协同产生包括 IL-12p70、IL-1β 和 TNF-α 在内的促炎细胞因子。这种组合还协同激活了参与 DC 成熟的 NF-κB 和多种 MAPK。此外，N1 和 R848 协同增加了干扰素（IFN）调节转录因子（如 IRF3 和 IRF7）的核转位，并促进了 I 型 IFN 如 IFN-α2、IFN-α4 和 IFN-β1 的表达。在小鼠骨髓来源的树突状细胞（BMDC）中也诱导了类似的信号通路。人 MoDC 的 RNA-seq 分析显示，N1 加 R848 协同上调了主要参与 DC 成熟途径的基因表达，特别是对 Th1 免疫反应极化至关重要的基因（例如， 和 等）。总的来说，我们的研究结果表明：（1）N1 与人源和鼠源 DC 中的 R848 协同激活；（2）基于各种细胞内信号事件的协同作用最终导致多个转录因子的激活。这些发现对于未来的临床试验具有重要意义，因为 N1 和 R848 协同促进了最佳的 Th1 谱系免疫反应，导致小鼠肿瘤排斥。
