Meley Daniel, Héraud Audrey, Gouilleux-Gruart Valerie, Ivanes Fabrice, Velge-Roussel Florence
EA 4245 Cellules Dendritiques, Immuno-modulation et Greffes, Université François-Rabelais de Tours, UFR de Médecine, Tours, France.
CNRS UMR 7292; Université François-Rabelais de Tours, UFR de Médecine, Tours, France.
Front Immunol. 2017 Aug 16;8:926. doi: 10.3389/fimmu.2017.00926. eCollection 2017.
Tocilizumab, a humanized anti-IL-6 receptor α (IL-6Rα) is widely used in the treatment of a panel of pathologies such as adult and juvenile rheumatoid arthritis (RA) and the systemic form of juvenile idiopathic arthritis in children. Its indications are expected to be largely extended to other inflammatory diseases in close future. Dendritic cells (DCs) appear to be deeply involved in the immunopathology of these diseases, yet the effects of tocilizumab on these cells were poorly studied. In this study, we explored the effect of tocilizumab on the regulation of IL-6R subunits [gp130, soluble form of IL-6Rα (sIL-6Rα), and mIL-6Rα] in human monocyte-derived DCs. Human DCs were derived from CD14 monocytes purified with beads with IL-4 and granulocyte macrophage colony-stimulating factor. cultures of DCs were performed in the presence of tocilizumab. Using lipopolysaccharide (LPS) maturation of DCs, we demonstrated that tocilizumab did not inhibit IL-6 secretion, enhanced mIL-6Rα expression, and largely increased sIL-6Rα secretion. MAPK modulated STAT3 phosphorylation and surface expression of IL-6Rα in LPS-DCs. Tocilizumab had no impact on STAT3 phosphorylation in LPS-DCs while both LPS and IL-6 increased its activation. Tocilizumab modulated the regulation of IL-6R subunits leading to an inflammatory status of DCs and a massive secretion of IL-6Rα. Our results demonstrate that DCs acquire a pro-inflammatory profile following tocilizumab treatment, becoming a major source of IL-6 -signaling activation that might explain the poor clinical benefit in some RA patients.
托珠单抗是一种人源化抗白细胞介素-6受体α（IL-6Rα）抗体，广泛用于治疗一系列病症，如成人和青少年类风湿性关节炎（RA）以及儿童系统性幼年特发性关节炎。预计在不久的将来其适应症将大幅扩展至其他炎症性疾病。树突状细胞（DCs）似乎深度参与了这些疾病的免疫病理学过程，然而托珠单抗对这些细胞的影响却鲜有研究。在本研究中，我们探讨了托珠单抗对人单核细胞来源的DCs中IL-6R亚基[gp130、可溶性IL-6Rα（sIL-6Rα）和mIL-6Rα]调节的影响。人DCs由用抗IL-4和粒细胞巨噬细胞集落刺激因子的磁珠纯化的CD14单核细胞衍生而来。DCs的培养在托珠单抗存在的情况下进行。利用脂多糖（LPS）使DCs成熟，我们证明托珠单抗不抑制IL-6分泌，增强mIL-6Rα表达，并大幅增加sIL-6Rα分泌。丝裂原活化蛋白激酶（MAPK）调节LPS刺激的DCs中信号转导和转录激活因子3（STAT3）的磷酸化以及IL-6Rα的表面表达。托珠单抗对LPS刺激的DCs中STAT3的磷酸化没有影响，而LPS和IL-6均增加其激活。托珠单抗调节IL-6R亚基的调节，导致DCs出现炎症状态并大量分泌IL-6Rα。我们的结果表明，托珠单抗治疗后DCs获得促炎表型，成为IL-6信号激活的主要来源，这可能解释了一些RA患者临床获益不佳的原因。
