Increased acute inflammation, leukotriene B4-induced chemotaxis, and signaling in mice deficient for G protein-coupled receptor kinase 6
Increased acute inflammation, leukotriene B4-induced chemotaxis, and signaling in mice deficient for G protein-coupled receptor kinase 6
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DOI：
10.4049/jimmunol.171.11.6128
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发表时间：
2003-12-01
影响因子：
4.4
通讯作者：
Heijnen, CJ
中科院分区：
文献类型：
--
作者：
Kavelaars, A;Vroon, A;Heijnen, CJ
中性粒细胞（PMN）的定向迁移是宿主防御入侵生物所必需的，而白三烯B-4（LTB 4）是最有效的PMN化学引诱剂之一。LTB 4通过与G蛋白偶联受体BLT 1结合发挥作用。G蛋白偶联受体被G蛋白偶联受体激酶（GRK）以激动剂依赖性方式磷酸化，导致受体脱敏。最近，已经表明人BLT 1是GRK 6的底物。为了研究GRK 6对PMN中炎症和LTB 4信号传导的生理重要性，我们使用GRK 6缺陷小鼠。在GRK 6（-/-）小鼠中，局部应用花生四烯酸后的急性炎症反应（耳肿胀和PMN流入耳中）显著增加。在体外，GRK 6（-/-）PMN表现出增加的趋化动力学和趋化反应LTB 4。GRK 6（-/-）PMN对LTB 4的反应是细胞内钙离子的长期增加和肌动蛋白聚合的延长，表明在GRK 6缺失的情况下LTB 4受体脱敏受损。然而，预先暴露于LTB 4使得GRK 6（-/-）以及野生型PMN对LTB 4的再刺激都是难治的，这表明GRK 6的存在对于该过程的发生不是必需的。总之，GRK 6缺乏导致BLT 1信号传导延长和中性粒细胞迁移增加。
Directed migration of polymorphonuclear neutrophils (PMN) is required for adequate host defense against invading organisms and leukotriene B-4 (LTB4) is one of the most potent PMN chemoattractants. LTB4 exerts its action via binding to BLT1, a G protein-coupled receptor. G protein-coupled receptors are phosphorylated by G protein-coupled receptor kinases (GRK) in an agonist-dependent manner, resulting in receptor desensitization. Recently, it has been shown that the human BLT1 is a substrate for GRK6. To investigate the physiological importance of GRK6 for inflammation and LTB4 signaling in PMN, we used GRK6-deficient mice. The acute inflammatory response (ear swelling and influx of PMN into the ear) after topical application of arachidonic acid was significantly increased in GRK6(-/-) mice. In vitro, GRK6(-/-) PMN showed increased chemokinetic and chemotactic responses to LTB4. GRK6(-/-) PMN respond to LTB4 with a prolonged increase in intracellular calcium and prolonged actin polymerization, suggesting impaired LTB4 receptor desensitization in the absence of GRK6. However, pre-exposure to LTB4 renders both GRK6(-/-) as well as wild-type PMN refractory to restimulation with LTB4, indicating that the presence of GRK6 is not required for this process to occur. In conclusion, GRK6 deficiency leads to prolonged BLT1 signaling and increased neutrophil migration.