A Role for the Low-Affinity A2B Adenosine Receptor in Regulating Superoxide Generation by Murine Neutrophils
A Role for the Low-Affinity A2B Adenosine Receptor in Regulating Superoxide Generation by Murine Neutrophils
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DOI：
10.1124/jpet.111.181792
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发表时间：
2011-09-01
影响因子：
3.5
通讯作者：
Auchampach, John A.
中科院分区：
文献类型：
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作者：
van der Hoeven, Dharini;Wan, Tina C.;Auchampach, John A.
腺苷的形成通过抑制免疫系统的大多数细胞来抑制炎症。在对中性粒细胞的作用中，腺苷抑制超氧化物生成并调节趋化活性。到目前为止，大多数证据表明G(S)蛋白偶联的A(2A)腺苷受体(AR)是主要的AR亚型，负责通过刺激cAMP的产生来介导腺苷对中性粒细胞的作用。鉴于目前已知A(2B)AR在中性粒细胞中表达，并且它是G(S)蛋白偶联受体，我们在这项研究中研究了它是否通过使用2[6-amino-3，5-dicyano-4[4-(cyclopropylmethoxy)苯基]吡啶-2-硫基]乙酰胺(BAY60-6583)抑制中性粒细胞活性，这是一种新的人A(2B)AR激动剂，在初步研究中被证实是一种有效和高选择性的小鼠A AR激动剂。我们发现，用低浓度(10(-9)和10(-8)M)的Bay 60-6583处理小鼠中性粒细胞，可以抑制甲酰化蛋氨酸-亮氨酸-苯丙氨酸(FMLP)刺激的超氧化物的产生，这些细胞是由幼稚的中性粒细胞、肿瘤坏死因子α启动的中性粒细胞或从系统内毒素处理的小鼠分离的中性粒细胞产生的。在用A(2B)AR基因敲除小鼠的中性粒细胞进行的实验中，证实了Bay 60-6583的这种抑制作用涉及A(2B)AR。值得注意的是，海湾60-6583增加了fMLP刺激的更高浓度的超氧化物产生(>；1muM)，这归因于AR非依赖效应。在标准的Boyden小室迁移实验中，Bay 60-6583本身并不刺激中性粒细胞的趋化作用，也不影响对fMLP的趋化作用。这些结果表明，A(2B)AR通过抑制小鼠中性粒细胞的氧化酶活性而发出信号，支持这种低亲和力的腺苷受体与A(2A)AR一起参与调节中性粒细胞的促炎作用的观点。
The formation of adenosine dampens inflammation by inhibiting most cells of the immune system. Among its actions on neutrophils, adenosine suppresses superoxide generation and regulates chemotactic activity. To date, most evidence implicates the G(s) protein-coupled A(2A) adenosine receptor (AR) as the primary AR subtype responsible for mediating the actions of adenosine on neutrophils by stimulating cAMP production. Given that the A(2B)AR is now known to be expressed in neutrophils and that it is a G(s) protein-coupled receptor, we examined in this study whether it signals to suppress neutrophil activities by using 2[6-amino-3,5-dicyano-4[4-(cyclopropylmethoxy) phenyl]pyridin-2-ylsulfanyl]acetamide (BAY 60-6583), a new agonist for the human A(2B)AR that was confirmed in preliminary studies to be a potent and highly selective agonist for the murine A AR. We found that treating mouse neutrophils with low concentrations (10(-9) and 10(-8) M) of BAY 60-6583 inhibited formylated-methionine-leucine-phenylalanine (fMLP)-stimulated superoxide production by either naive neutrophils, tumor necrosis factor-alpha-primed neutrophils, or neutrophils isolated from mice treated systemically with lipopolysaccharide. This inhibitory action of BAY 60-6583 was confirmed to involve the A(2B)AR in experiments using neutrophils obtained from A(2B)AR gene knockout mice. It is noteworthy that BAY 60-6583 increased fMLP-stimulated superoxide production at higher concentrations (>1 mu M), which was attributed to an AR-independent effect. In a standard Boyden chamber migration assay, BAY 60-6583 alone did not stimulate neutrophil chemotaxis or influence chemotaxis in response to fMLP. These results indicate that the A(2B)AR signals to suppress oxidase activity by murine neutrophils, supporting the idea that this low-affinity receptor for adenosine participates along with the A(2A)AR in regulating the proinflammatory actions of neutrophils.