University of São Paulo, Ribeirão Preto Medical School, Ribeirao Preto, Sao Paulo, Brazil.
Arthritis Rheumatol. 2015 Jul;67(7):1751-9. doi: 10.1002/art.39117.
Infiltration of neutrophils into the joints plays an important role in bone erosion and articular destruction in rheumatoid arthritis (RA). Neutrophil trafficking during inflammation is a process that involves activation of chemotactic receptors. Recent findings suggest that changes in chemotactic receptor patterns could occur in neutrophils under certain inflammatory conditions. The aim of this study was to evaluate the gain of responsiveness of neutrophils to CCL2 in RA patients and to assess the role of CCL2 in driving neutrophil infiltration into the joints.
Neutrophils were purified from the peripheral blood of patients with RA or from mice with antigen-induced arthritis (AIA). Expression of CCR2 was evaluated using polymerase chain reaction, flow cytometry, and immunofluorescence analyses. In vitro chemotaxis to CCL2 was assayed to evaluate the functional significance of de novo CCR2 expression. The murine AIA model was used to evaluate the in vivo role of CCR2 in neutrophil infiltration into the joints.
High CCR2 expression and responsiveness to CCL2 were observed in neutrophils from the blood of patients with early RA and in neutrophils from the blood and bone marrow of mice with AIA. Genetic deficiency or pharmacologic inhibition of CCR2 protected against the infiltration of neutrophils into the joints. This protection was not associated with an impairment of the neutrophil chemotactic ability or CXC chemokine production in the joints. Moreover, adoptive transfer of wild-type mouse neutrophils to CCR2-deficient mice restored neutrophil infiltration and the articular mechanical hyperalgesia associated with joint inflammation.
These findings suggest that CCR2 is directly involved in the detrimental infiltration of neutrophils into the joints in patients with RA, showing a new inflammatory role of CCR2 during RA flares or active disease.
中性粒细胞浸润关节在类风湿关节炎（RA）中骨侵蚀和关节破坏中起重要作用。炎症期间的中性粒细胞迁移是一个涉及趋化受体激活的过程。最近的研究结果表明，在某些炎症条件下，中性粒细胞中趋化受体模式的变化可能会发生。本研究旨在评估 RA 患者中性粒细胞对 CCL2 反应性的获得，并评估 CCL2 在驱动中性粒细胞浸润关节中的作用。
从 RA 患者或抗原诱导性关节炎（AIA）小鼠的外周血中纯化中性粒细胞。使用聚合酶链反应、流式细胞术和免疫荧光分析评估 CCR2 的表达。体外趋化分析评估新表达的 CCR2 的功能意义。使用鼠 AIA 模型评估 CCR2 在中性粒细胞浸润关节中的体内作用。
在早期 RA 患者血液中的中性粒细胞和 AIA 小鼠血液和骨髓中的中性粒细胞中观察到高 CCR2 表达和对 CCL2 的反应性。CCR2 的遗传缺陷或药理学抑制可防止中性粒细胞浸润关节。这种保护与关节中中性粒细胞趋化能力或 CXCL 趋化因子产生的损害无关。此外，将野生型小鼠中性粒细胞过继转移至 CCR2 缺陷型小鼠可恢复与关节炎症相关的中性粒细胞浸润和关节机械性痛觉过敏。
这些发现表明，CCR2 直接参与 RA 患者关节中中性粒细胞的有害浸润，在 RA 发作或活动期显示了 CCR2 的新的炎症作用。
