γ-amino butyric acid type B receptors stimulate neutrophil chemotaxis during ischemia-reperfusion
γ-amino butyric acid type B receptors stimulate neutrophil chemotaxis during ischemia-reperfusion
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DOI：
10.4049/jimmunol.174.11.7242
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发表时间：
2005-06-01
影响因子：
4.4
通讯作者：
Klein, JB
中科院分区：
文献类型：
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作者：
Rane, MJ;Gozal, D;Klein, JB
丝氨酸/苏氨酸激酶Akt，或蛋白激酶B，已被证明调节许多中性粒细胞的功能。我们试图鉴定中性粒细胞中的Akt结合蛋白，以进一步了解Akt调节各种中性粒细胞功能的机制。蛋白质组学和免疫沉淀研究证实，γ-氨基丁酸(GABA)B型受体2(GABA(B)R2)是人中性粒细胞中一种Akt结合蛋白。经Akt免疫沉淀和抗GABA(B)R2免疫印迹的中性粒细胞裂解物显示Akt与完整的GABA(B)R结合，与抗GABA(B)R2抗体相互免疫沉淀得到类似的结果。此外，共聚焦显微镜显示GABA(B)R2与Akt共定位。GABA(B)R激动剂巴氯芬以依赖PI3K的方式激活Akt并刺激中性粒细胞定向迁移，而GABA(B)R拮抗剂CGP52432则阻断这一作用。巴氯芬以PI3K依赖的方式刺激中性粒细胞趋化和微管蛋白重组。此外，一种GABA(B)受体激动剂未能刺激中性粒细胞超氧化物歧化。我们不知道GABA(B)R与Akt在任何细胞类型中的关联。目前的研究首次表明，人中性粒细胞中存在大脑特异性受体GABA(B)R2，并且它在功能上与Akt有关。脑室注射巴氯芬预处理的大鼠中风模型显示，中性粒细胞向缺血损伤的迁移增加。因此，GABA(B)R在中性粒细胞中功能性表达，并通过Akt依赖的途径作为趋化受体发挥作用。GABA(B)受体在炎症反应和中性粒细胞依赖的脑缺血再灌注损伤(如卒中)中可能发挥重要作用。
Serine/threonine kinase Akt, or protein kinase B, has been shown to regulate a number of neutrophil functions. We sought to identify Akt binding proteins in neutrophils to provide further insights into understanding the mechanism by which Akt regulates various neutrophil functions. Proteomic and immunoprecipitation studies identified gamma-amino butyric acid (GABA) type B receptor 2 (GABA(B)R2) as an Akt binding protein in human neutrophils. Neutrophil lysates subjected to Akt immunoprecipitation followed by immunoblotting with anti-GABA(B)R2 demonstrated Akt association with the intact GABA(B)R. Similar results were obtained when reciprocal immunoprecipitations were performed with anti-GABA(B)R2 Ab. Additionally, GABA(B)R2 and Akt colocalization was demonstrated by confocal microscopy. A GABA(B)R agonist, baclofen, activated Akt and stimulated neutrophil-directed migration in a PI3K-dependent manner, whereas CGP52432, a GABA(B)R antagonist blocked such effects. Baclofen, stimulated neutrophil chemotaxis and tubulin reorganization in a PI3K-dependent manner. Additionally, a GABA(B)R agonist failed to stimulate neutrophil superoxide burst. We are unaware of the association of GABA(B)R with Akt in any cell type. The present study shows for the first time that a brain-specific receptor, GABA(B)R2 is present in human neutrophils and that it is functionally associated with Akt. Intraventricular baclofen pretreatment in rats subjected to a stroke model showed increased migration of neutrophils to the ischemic lesion. Thus, the GABA(B)R is functionally expressed in,neutrophils, and acts as a chemoattractant receptor via an Akt-dependent pathway. The GABA(B)R potentially plays a significant role in the inflammatory response and neutrophil-dependent ischemia-reperfusion injury such as stroke.