Objective The interleukin (IL)23 pathway contributes to IBD pathogenesis and is being actively studied as a therapeutic target in patients with IBD. Unexpected outcomes in these therapeutic trials have highlighted the importance of understanding the cell types and mechanisms through which IL23 regulates immune outcomes. How IL23 regulates macrophage outcomes and the consequences of the IL23R R381Q IBD-protective variant on macrophages are not well defined; macrophages are key players in IBD pathogenesis and inflammation. Design We analysed protein and RNA expression, signalling and localisation in human monocyte-derived macrophages (MDMs) through western blot, ELISA, real-time PCR, flow cytometry, immunoprecipitation and microscopy. Results IL23R was critical for optimal levels of pattern-recognition receptor (PRR)-induced signalling and cytokines in human MDMs. In contrast to the coreceptor IL12Rβ1, IL23 induced dynamic IL23R cell surface regulation and this required clathrin and dynamin-mediated endocytosis and endocytic recycling-dependent pathways; these pathways were essential for IL23R-mediated outcomes. The IBD-protective IL23R R381Q variant showed distinct outcomes. Relative to IL23R R381, HeLa cells expressing IL23R Q381 showed decreased IL23R recycling and reduced assembly of IL23R Q381 with Janus kinase/signal transducer and activator of transcription pathway members. In MDMs from IL23R Q381 carriers, IL23R accumulated in late endosomes and lysosomes on IL23 treatment and cells demonstrated decreased IL23R- and PRR-induced signalling and cytokines relative to IL23R R381 MDMs. Conclusion Macrophage-mediated inflammatory pathways are key contributors to IBD pathogenesis, and we identify an autocrine/paracrine IL23 requirement in PRR-initiated human macrophage outcomes and in human intestinal myeloid cells, establish that IL23R undergoes ligand-induced recycling, define mechanisms regulating IL23R-induced signalling and determine how the IBD-protective IL23R R381Q variant modulates these processes.

中文翻译：

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IL23 诱导 IL23R 再循环并放大人类巨噬细胞中先天受体诱导的信号和细胞因子，IBD 保护性 IL23R R381Q 变体调节这些结果

目的 白细胞介素 (IL)23 通路有助于 IBD 的发病机制，并且作为 IBD 患者的治疗靶点正在被积极研究。这些治疗试验中的意外结果凸显了了解 IL23 调节免疫结果的细胞类型和机制的重要性。IL23 如何调节巨噬细胞结果以及 IL23R R381Q IBD 保护性变异对巨噬细胞的影响尚未明确；巨噬细胞是 IBD 发病机制和炎症的关键参与者。设计 我们通过蛋白质印迹、ELISA、实时 PCR、流式细胞术、免疫沉淀和显微镜分析了人类单核细胞衍生的巨噬细胞 (MDM) 中的蛋白质和 RNA 表达、信号传导和定位。结果 IL23R 对于人类 MDM 中模式识别受体 (PRR) 诱导的信号传导和细胞因子的最佳水平至关重要。与辅助受体 IL12Rβ1 相比，IL23 诱导动态 IL23R 细胞表面调节，这需要网格蛋白和动力蛋白介导的内吞作用和内吞循环依赖途径；这些途径对于 IL23R 介导的结果至关重要。IBD 保护性 IL23R R381Q 变体显示出不同的结果。相对于 IL23R R381，表达 IL23R Q381 的 HeLa 细胞显示出减少的 IL23R 再循环和减少 IL23R Q381 与 Janus 激酶/信号转导器和转录通路成员激活剂的组装。在来自 IL23R Q381 载体的 MDM 中，IL23R 在 IL23 处理后在晚期内体和溶酶体中积累，细胞显示出相对于 IL23R R381 MDM 而言，IL23R 和 PRR 诱导的信号传导和细胞因子减少。结论 巨噬细胞介导的炎症通路是 IBD 发病机制的关键因素，我们确定了 PRR 启动的人类巨噬细胞结果和人类肠道骨髓细胞中自分泌/旁分泌 IL23 的需求，确定 IL23R 经历配体诱导的再循环，确定调节 IL23R-的机制诱导信号并确定 IBD 保护性 IL23R R381Q 变体如何调节这些过程。