Signal transduction in smooth muscle -: Selected contribution:: Tryptase-induced PAR-2-mediated Ca2+ signaling in human airway smooth muscle cells
Signal transduction in smooth muscle -: Selected contribution:: Tryptase-induced PAR-2-mediated Ca2+ signaling in human airway smooth muscle cells
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DOI：
10.1152/jappl.2001.91.2.995
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发表时间：
2001-08-01
影响因子：
3.3
通讯作者：
Marthan, R
中科院分区：
文献类型：
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作者：
Berger, P;Tunon-de-Lara, JM;Marthan, R
胰蛋白酶是肥大细胞的主要产物，被认为在气道炎症和高反应性中起重要作用。胰蛋白酶对气道反应性（支气管保护和/或气道收缩）产生不同的，有时是相反的作用。本研究旨在探讨人肺胰蛋白酶和合成活化肽（AP） SLIGKV-NH2活化蛋白酶活化受体(PAR)-2对人气道平滑肌（HASM）细胞Ca2+信号传导的影响。免疫细胞化学显示PAR-2在HASM细胞中表达。Tryptase （7.5-30 mU/ml）诱导细胞质Ca2+浓度（[Ca2+](i)）的浓度依赖的短暂相对上升，达到207 +/- 32 nM (n = 10)，通过indo - 1荧光光谱测定。蛋白酶抑制剂lepeptin或benzamidine （100 muM）可消除胰蛋白酶诱导的[Ca2+](i)升高。AP （1-100 mM）对PAR-2的激活也诱导了[Ca2+]浓度依赖性的短暂升高(i)，而反向肽则没有产生影响。在胰蛋白酶或AP的反复刺激下，[Ca2+](i)反应发生了同源脱敏。U-73122，一种特异性磷脂酶C （PLC）拮抗剂，xestospongin，一种肌醇三磷酸（IP3）受体拮抗剂，或thapsigargin，一种肌浆Ca2+- atp酶抑制剂，消除了胰蛋白酶诱导的[Ca2+](i)反应，而Ca2+去除，在额外的EGTA存在下，没有影响。Calphostin C，一种蛋白激酶C抑制剂，增加PAR-2 [Ca2+](i)反应。我们的研究结果表明，胰蛋白酶激活了[Ca2+](i)反应，这种反应在HASM细胞中以PAR-2介导的形式出现。信号转导通过PLC激活从而通过IP3途径暗示细胞内Ca2+储存。本研究提供的证据表明，胰蛋白酶作为气道炎症和高反应性的重要介质，在气道平滑肌部位也是一种有效的直接激动剂。
Tryptase, the major mast cell product, is considered to play an important role in airway inflammation and hyperresponsiveness. Tryptase produces different, sometimes opposite, effects on airway responsiveness (broncho-protection and/or airway contraction). This study was designed to examine the effect of human lung tryptase and activation of protease-activated receptor (PAR)-2 by synthetic activated peptide (AP) SLIGKV-NH2 on Ca2+ signaling in human airway smooth muscle (HASM) cells. Immunocytochemistry revealed that PAR-2 was expressed by HASM cells. Tryptase (7.5-30 mU/ml) induced a concentration-dependent transient relative rise in cytoplasmic Ca2+ concentration ([Ca2+](i)) that reached 207 +/- 32 nM (n = 10) measured by indo 1 spectrofluorometry. The protease inhibitors leupeptin or benzamidine (100 muM) abolished tryptase-induced [Ca2+](i) increase. Activation of PAR-2 by AP (1-100 mM) also induced a concentration-dependent transient rise in [Ca2+](i), whereas the reverse peptide produced no effect. There was a homologous desensitization of the [Ca2+](i) response on repeated stimulation with tryptase or AP. U-73122, a specific phospholipase C (PLC) antagonist, xestospongin, an inositol trisphosphate (IP3)-receptor antagonist, or thapsigargin, a sarcoplamic Ca2+-ATPase inhibitor, abolished tryptase-induced [Ca2+](i) response, whereas Ca2+ removal, in the additional presence of EGTA, had no effect. Calphostin C, a protein kinase C inhibitor, increased PAR-2 [Ca2+](i) response. Our results indicate that tryptase activates a [Ca2+](i) response, which appears as PAR-2 mediated in HASM cells. Signal transduction implicates the intracellular Ca2+ store via PLC activation and thus via the IP3 pathway. This study provides evidence that tryptase, which is increasingly recognized as an important mediator in airway inflammation and hyperresponsiveness, is also a potent direct agonist at the site of airway smooth muscle.