Institute for Tissue Transplantation and Immunology, Jinan University, Guangzhou, China.
PLoS One. 2012;7(5):e34830. doi: 10.1371/journal.pone.0034830. Epub 2012 May 31.
Abnormal inflammations are central therapeutic targets in numerous infectious and autoimmune diseases. Dendritic cells (DCs) are involved in these inflammations, serving as both antigen presenters and proinflammatory cytokine providers. As an immuno-suppressor applied to the therapies of multiple sclerosis and allograft transplantation, fingolimod (FTY720) was shown to affect DC migration and its crosstalk with T cells. We posit FTY720 can induce an anergy-polarized phenotype switch on DCs in vitro, especially upon endotoxic activation. A lipopolysaccharide (LPS)-induced mouse bone marrow-derived dendritic cell (BMDC) activation model was employed to test FTY720-induced phenotypic changes on immature and mature DCs. Specifically, methods for morphology, nanostructure, cytokine production, phagocytosis, endocytosis and specific antigen presentation studies were used. FTY720 induced significant alterations of surface markers, as well as decline of shape indices, cell volume, surface roughness in LPS-activated mature BMDCs. These phenotypic, morphological and topographical changes were accompanied by FTY720-mediated down-regulation of proinflammatory cytokines, including IL-6, TNF-α, IL-12 and MCP-1. Together with suppressed nitric oxide (NO) production and CCR7 transcription in FTY720-treated BMDCs with or without LPS activation, an inhibitory mechanism of NO and cytokine reciprocal activation was suggested. This implication was supported by the impaired phagocytotic, endocytotic and specific antigen presentation abilities observed in the FTY720-treated BMDCs. In conclusion, we demonstrated FTY720 can induce anergy-polarization in both immature and LPS-activated mature BMDCs. A possible mechanism is FTY720-mediated reciprocal suppression on the intrinsic activation pathway and cytokine production with endpoint exhibitions on phagocytosis, endocytosis, antigen presentation as well as cellular morphology and topography.
异常炎症是许多感染性和自身免疫性疾病的重要治疗靶点。树突状细胞（DCs）参与这些炎症反应，既是抗原呈递细胞，也是促炎细胞因子的提供者。作为一种应用于多发性硬化症和同种异体移植治疗的免疫抑制剂，芬戈莫德（FTY720）已被证明可影响 DC 的迁移及其与 T 细胞的相互作用。我们假设 FTY720 可在体外诱导 DC 产生无能表型，特别是在脂多糖（LPS）激活后。采用 LPS 诱导的小鼠骨髓来源树突状细胞（BMDC）激活模型来检测 FTY720 对未成熟和成熟 DC 表型变化的影响。具体方法包括形态学、纳米结构、细胞因子产生、吞噬作用、内吞作用和特定抗原呈递研究。FTY720 诱导 LPS 激活的成熟 BMDC 表面标志物显著改变，形态指数、细胞体积和表面粗糙度下降。这些表型、形态和形貌变化伴随着 FTY720 介导的促炎细胞因子（包括 IL-6、TNF-α、IL-12 和 MCP-1）的下调。与 LPS 激活或不激活的 FTY720 处理的 BMDC 中抑制型一氧化氮（NO）产生和 CCR7 转录一起，提示存在 NO 和细胞因子相互激活的抑制机制。这一推论得到了 FTY720 处理的 BMDC 中观察到的吞噬作用、内吞作用和特定抗原呈递能力受损的支持。总之，我们证明 FTY720 可诱导未成熟和 LPS 激活的成熟 BMDC 产生无能表型。一种可能的机制是 FTY720 介导的固有激活途径和细胞因子产生的相互抑制，终点表现为吞噬作用、内吞作用、抗原呈递以及细胞形态和形貌。
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