Ion transport regulated by protease-activated receptor 2 in human airway Calu-3 epithelia
Ion transport regulated by protease-activated receptor 2 in human airway Calu-3 epithelia
复制标题
DOI：
10.1038/sj.bjp.0706330
复制
发表时间：
2005-10-01
影响因子：
7.3
通讯作者：
Kume, H
中科院分区：
文献类型：
--
作者：
Sato, S;Ito, Y;Kume, H
我们利用极化的人气道Calu-3细胞，研究了蛋白酶激活受体2 （PAR2）介导阴离子分泌的机制及其在离子转运调节中的作用。胰蛋白酶和PAR2激活肽（PAR2AP）对PAR2的刺激，特别是从基底侧来看，由于胞浆内Ca2+的动员，引起短暂的Cl-分泌PI-PLC拮抗剂（U73122, ET-18-OCH3）和肌醇1,4,5-三磷酸（xestonin C, Xest C）对par2ap介导的Cl-分泌无影响，而PC-PLC抑制剂D609和PKC激活剂phorbol 12-肉鸡酸酯13醋酸酯（PMA， PKC激活剂）对其有减弱作用即使在暴露10分钟后去除PAR2AP 30分钟后，细胞对PAR2刺激的反应仍然很差，但PKC抑制剂GF109203X （GFX）上调了这种降低的反应性PAR2AP预处理不影响阴离子分泌剂（如异丙肾上腺素、福斯克林、thapsigargin、1-乙基-2-苯并唑啉酮和腺苷）的应答，但atp诱导的应答显著降低。制霉菌素渗透研究表明，PAR2AP的存在阻止了atp诱导的基底侧膜K+电导率的增加，而不影响根尖膜Cl-电导率对D609和PMA敏感的atp诱导的Ca2+动员被PAR2AP预处理抑制，这种抑制被GFX.7的存在减弱。总的来说，PAR2的刺激通过pc - plc介导的途径产生Cl-分泌的短暂反应，随后不仅PAR2本身的自身脱敏，而且pc - plc偶联的嘌呤受体的交叉脱敏。这两种类型的脱敏似乎都有pkc介导的PC-PLC的下调。
1 We examined the mechanisms underlying anion secretion mediated by protease-activated receptor2 (PAR2) and its role in the regulation of ion transport, using polarized human airway Calu-3 cells. 2 PAR2 stimulation by trypsin and a PAR2-activating peptide (PAR2AP), especially from the basolateral aspect, caused transient Cl- secretion due to cytosolic Ca2+ mobilization.3 Antagonists of PI-PLC (U73122, ET-18-OCH3) and inositol 1,4,5-triphosphate (xestospongin C (Xest C)) were without effect on thePAR2AP- mediated Cl- secretion, whereas it was attenuated by D609 ( a PC-PLC inhibitor) and phorbol 12-myristate 13 acetate (PMA, a PKC activator).4 Even 30 min after removal of PAR2AP after a 10-min-exposure, cells were still poorly responsive to PAR2 stimulation, but the reduced responsiveness was upregulated by a PKC inhibitor, GF109203X (GFX).5 Pretreatment with PAR2AP did not affect responses to anion secretagogues, such as isoproterenol, forskolin, thapsigargin, 1-ethyl-2-benzimdazolinone, and adenosine, but ATP-induced responses were significantly reduced. Nystatin permeabilization studies revealed that the presence of PAR2AP prevented ATP-induced increments in basolateral membrane K+ conductance without affecting apical membrane Cl- conductance.6 ATP-elicited Ca2+ mobilization, which was sensitive to D609 and PMA, was inhibited by the pretreatment with PAR2AP, and this inhibition was blunted by the presence of GFX.7 Collectively, stimulation of PAR2 generates a brief response of Cl- secretion through PC-PLC-mediated pathway, followed by not only auto-desensitization of PAR2 itself but also cross-desensitization of a PC-PLC-coupled purinoceptor. The two types of desensitization seem likely to have PKC-mediated downregulation of PC-PLC in common.