A3 adenosine receptor activation triggers phosphorylation of protein kinase B and protects rat basophilic leukemia 2H3 mast cells from apoptosis
A3 adenosine receptor activation triggers phosphorylation of protein kinase B and protects rat basophilic leukemia 2H3 mast cells from apoptosis
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DOI：
10.1124/mol.59.1.76
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发表时间：
2001-01-01
影响因子：
3.6
通讯作者：
Linden, J
中科院分区：
文献类型：
--
作者：
Gao, ZH;Li, BS;Linden, J
腺苷在发炎或缺血组织中积累到高水平，并激活肥大细胞上的A（3）腺苷受体（AR），引发脱粒。在这里，我们表明，刺激大鼠嗜碱性白血病（RBL）-2H3肥大样细胞与A（3）AR激动剂N-6-（3-碘）苄基-5 '-N-甲基甲酰氨基腺苷（IB-MECA; 10 nM）或肌苷（10 μ M）刺激蛋白激酶B（Akt）的磷酸化。IB-MECA（1 μ M）还导致由RBL-2 H3细胞暴露于UV光引起的细胞凋亡减少>50%。Akt磷酸化不受100 nM N-6-环戊基腺苷（A（1）-选择性）或CGS 21680（A（2A）-选择性）刺激，并且在用渥曼青霉素或百日咳毒素预处理的细胞中不存在。在放射性配体结合试验中测定了AR拮抗剂BW-1433和8-磺苯基茶碱（8-SPT）对所有四种大鼠AR亚型的K-I值：BW-1433（A（1），5.8 ± 1.0 nM; A（2A），240 ± 37; A（2B），30 ± 10; A（3），12，300 ± 3，700）; 8-SPT（A（1），3.2 ± 1.2 μ M; A（2A），57 ± 4; A（2B），2.2 ± 0.8; A（3），>100）。BW-1433和A（3）选择性拮抗剂MRS 1523（5 μ M），而不是8-SPT（100 μ M），阻断IB-MECA诱导的细胞凋亡保护，证实A（3）AR是抗细胞凋亡反应的介导物。这些数据表明，腺苷和肌苷激活Gi偶联的A（3）AR，通过涉及Gi的β-γ亚基、磷脂酰肌醇3-激酶β和Akt的途径保护肥大细胞免于凋亡。我们推测，肥大细胞或其他表达A（3）AR的细胞（例如，嗜酸性粒细胞）可以促进它们在发炎组织中的存活和积累。
Adenosine accumulates to high levels in inflamed or ischemic tissues and activates A(3) adenosine receptors (ARs) on mast cells to trigger degranulation. Here we show that stimulation of rat basophilic leukemia (RBL)-2H3 mast-like cells with the A(3) AR agonists N-6-(3-iodo) benzyl-5'-N-methylcarboxamidodoadenosine (IB-MECA; 10 nM) or inosine (10 muM) stimulates phosphorylation of protein kinase B (Akt). IB-MECA (1 muM) also causes a >50% reduction in apoptosis caused by exposure of RBL-2H3 cells to UV light. Akt phosphorylation is not stimulated by 100 nM N-6-cyclopentyladenosine (A(1)-selective) or CGS21680 (A(2A)-selective) and is absent in cells pretreated with wortmannin or pertussis toxin. The K-I values of the AR antagonists BW-1433 and 8-sulfophenyltheophylline (8-SPT) were determined in radioligand binding assays for all four subtypes of rat ARs: BW-1433 (A(1), 5.8 +/- 1.0 nM; A(2A), 240 +/- 37; A(2B),30 +/- 10; A(3), 12,300 +/- 3,700); 8-SPT (A(1), 3.2 +/- 1.2 muM; A(2A),57 +/- 4; A(2B), 2.2 +/- 0.8; A(3), >100). BW-1433 and the A(3)-slective antagonist MRS1523 (5 muM), but not 8-SPT (100 muM), block IB-MECA-induced protection from apoptosis, confirming the A(3) AR as the mediator of the antiapoptotic response. The data suggest that adenosine and inosine activate Gi-coupled A(3) ARs to protect mast cells from apoptosis by a pathway involving the beta gamma subunits of Gi, phosphatidylinositol 3-kinase beta, and Akt. We speculate that activation of A(3) ARs on mast cells or other cells that express A(3) ARs (e.g., eosinophils) may facilitate their survival and accumulation in inflamed tissues.