Elsner J, Mack M, Brühl H, Dulkys Y, Kimmig D, Simmons G, Clapham P R, Schlöndorff D, Kapp A, Wells T N, Proudfoot A E
Department of Dermatology and Allergology, Hannover Medical University, 30449 Hannover, Germany.
J Biol Chem. 2000 Mar 17;275(11):7787-94. doi: 10.1074/jbc.275.11.7787.
RANTES (regulated on activation normal T cell expressed) has been found at elevated levels in biological fluids from patients with a wide range of allergic and autoimmune diseases and is able to attract several subtypes of leukocytes including eosinophils and monocytes into inflamed tissue. Amino-terminal modifications of RANTES produce receptor antagonists which are candidates for blocking this cellular recruitment. Met-RANTES has been shown to modulate inflammation in vivo, while AOP-RANTES is a potent inhibitor of R5 human immunodeficiency virus type 1 (HIV-1) strains and has been shown to down-modulate CCR5 and prevent recycling of the receptor. We have studied the effect of AOP-RANTES in eosinophil activation and have found that it is able to efficiently elicit eosinophil effector functions through CCR3, as measured by the release of reactive oxygen species and calcium mobilization, whereas Met-RANTES is inactive in these assays. AOP-RANTES is found to inhibit CCR3-mediated HIV-1 infection with moderate potency, in contrast to its potent inhibition of CCR5-mediated HIV-1 infection. Furthermore, we have investigated the abilities of these modified proteins to down-modulate CCR1 and CCR3 from the surface of monocytes and eosinophils. We show here that AOP-RANTES is much less effective than RANTES in down-modulation of CCR1. Surprisingly, recycling of CCR1 was minimal after incubation with RANTES while there was complete recycling with AOP-RANTES. In the case of CCR3, no significant difference was found between RANTES and AOP-RANTES in down-modulation and recycling. It therefore appears that trafficking of RANTES receptors follows different patterns, which opens up potential new targets for therapeutic intervention.
调节激活正常T细胞表达的趋化因子（RANTES）在患有多种过敏性和自身免疫性疾病患者的生物体液中水平升高，并且能够吸引包括嗜酸性粒细胞和单核细胞在内的几种白细胞亚型进入炎症组织。RANTES的氨基末端修饰产生受体拮抗剂，这些拮抗剂是阻断这种细胞募集的候选物。已证明甲硫氨酸-RANTES（Met-RANTES）在体内调节炎症，而丙氨酸-缬氨酸-丙氨酸-脯氨酸-精氨酸-RANTES（AOP-RANTES）是R5型人类免疫缺陷病毒1型（HIV-1）毒株的有效抑制剂，并已证明其可下调趋化因子受体5（CCR5）并阻止该受体的再循环。我们研究了AOP-RANTES对嗜酸性粒细胞激活的影响，发现它能够通过CCR3有效地引发嗜酸性粒细胞效应功能，这通过活性氧释放和钙动员来衡量，而Met-RANTES在这些试验中无活性。与它对CCR5介导的HIV-1感染的有效抑制相反，发现AOP-RANTES以中等效力抑制CCR3介导的HIV-1感染。此外，我们研究了这些修饰蛋白从单核细胞和嗜酸性粒细胞表面下调CCR1和CCR3的能力。我们在此表明，AOP-RANTES在下调CCR1方面比RANTES效果差得多。令人惊讶的是，与RANTES孵育后CCR1的再循环极少，而与AOP-RANTES孵育后则完全再循环。在CCR3的情况下，RANTES和AOP-RANTES在下调和再循环方面没有发现显著差异。因此，似乎RANTES受体的运输遵循不同的模式，这为治疗干预开辟了潜在的新靶点。
