Department of Medical Sciences, Rheumatology, Science for Life Laboratory, Uppsala University, Rudbecklaboratoriet, Dag Hammarskjölds v 20, C11, 751 85, Uppsala, Sweden.
Arthritis Res Ther. 2020 Jun 5;22(1):130. doi: 10.1186/s13075-020-02186-z.
Patients with systemic lupus erythematosus (SLE) have an ongoing interferon (IFN) production due to an activation of plasmacytoid dendritic cells (pDCs), which can be triggered to type I IFN synthesis by RNA containing immune complexes (RNA-IC). Considering emerging data suggesting a role of type III IFN in the SLE disease process, we asked if RNA-IC can induce type III IFN production in pDC and how this production can be regulated.
Peripheral blood mononuclear cells (PBMCs) or immune cell subsets were isolated from healthy blood donors or SLE patients and stimulated with IC containing U1 snRNP and SLE-IgG (RNA-IC). Hydroxychloroquine (HCQ) and an interleukin receptor 1-associated kinase 4 inhibitor (IRAK4i) were added to cell cultures. Cytokine mRNA levels were determined with a microarray and protein levels with immunoassays. Single-cell RNA sequencing of pDCs using ddSEQ technology was performed.
Type III IFN mRNA and protein was induced in RNA-IC-stimulated pDC-NK and pDC-B cell co-cultures. A subset of activated pDCs (3%) expressed both type III and type I IFN mRNA. IFN-λ2, IFN-α2b, interleukin (IL)-3, IL-6, or granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced IFN-λ1/3 production 2-5-fold. HCQ and an IRAK4i blocked the RNA-IC-triggered IFN-λ1/3 production (p < 0.01). IFN-α2b and GM-CSF increased the proportion of SLE patients producing IFN-λ1/3 in response to RNA-IC from 11 to 33%.
Type III IFN production is triggered by RNA-IC in pDCs in a TLR-MyD88-dependent manner, enhanced by NK and B cells as well as several pro-inflammatory cytokines. These results support a contributing role for both type I and type III IFNs in SLE, which needs to be considered when targeting the IFN system in this disease.
由于浆细胞样树突状细胞（pDC）的激活，红斑狼疮（SLE）患者持续产生干扰素（IFN），而 RNA 免疫复合物（RNA-IC）可触发 I 型 IFN 合成。鉴于新出现的数据表明 III 型 IFN 在 SLE 发病机制中起作用，我们想知道 RNA-IC 是否可以诱导 pDC 产生 III 型 IFN，以及这种产生如何受到调节。
从健康献血者或 SLE 患者中分离外周血单核细胞（PBMC）或免疫细胞亚群，并使用含有 U1 snRNP 和 SLE-IgG 的 IC（RNA-IC）进行刺激。向细胞培养物中添加羟氯喹（HCQ）和白细胞介素受体 1 相关激酶 4 抑制剂（IRAK4i）。使用微阵列测定细胞因子 mRNA 水平，并使用免疫测定法测定蛋白水平。使用 ddSEQ 技术对 pDC 进行单细胞 RNA 测序。
在 RNA-IC 刺激的 pDC-NK 和 pDC-B 细胞共培养物中诱导了 III 型 IFN mRNA 和蛋白。激活的 pDC 亚群（3%）表达 III 型和 I 型 IFN mRNA。IFN-λ2、IFN-α2b、白细胞介素（IL）-3、IL-6 或粒细胞-巨噬细胞集落刺激因子（GM-CSF）将 IFN-λ1/3 产生增强 2-5 倍。HCQ 和 IRAK4i 阻断了 RNA-IC 触发的 IFN-λ1/3 产生（p<0.01）。IFN-α2b 和 GM-CSF 将对 RNA-IC 产生 IFN-λ1/3 的 SLE 患者比例从 11%增加到 33%。
RNA-IC 通过 TLR-MyD88 依赖性方式在 pDC 中触发 III 型 IFN 产生，由 NK 和 B 细胞以及几种促炎细胞因子增强。这些结果支持 I 型和 III 型 IFN 在 SLE 中均起作用，在针对该疾病的 IFN 系统时需要考虑这一点。
