Species and response dependent differences in the effects of MAPK inhibitors on P2X7 receptor function
Species and response dependent differences in the effects of MAPK inhibitors on P2X7 receptor function
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DOI：
10.1038/sj.bjp.0706938
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发表时间：
2006-12-01
影响因子：
7.3
通讯作者：
Humphrey, P. P. A.
中科院分区：
文献类型：
--
作者：
Michel, A. D.;Thompson, K. M.;Humphrey, P. P. A.
背景资料：最近的研究表明，有丝分裂原活化蛋白激酶（MAPK）参与了天然组织中P2 X（7）受体激活后细胞通透性的变化。在本研究中，我们进一步研究了MAPK抑制剂对重组和天然P2 X7受体的作用。实验方法：使用一系列实验方法，在表达重组P2 X7受体的HEK 293细胞和表达天然人P2 X7受体的THP-1细胞中检测了MAPK抑制剂SB-203580、SB-202190和SB-242235。在人重组P2 X7受体上，SB-203580和SB-202190是2 '-和3'-O-（4-苯甲酰基苯甲酰基）-ATP（BzATP）刺激的乙锭蓄积的弱非竞争性抑制剂（pIC 50 = 4.8-6.4），但SB-242235（0.1-10 μ M）无作用。SB-203580和SB-202190对大鼠或小鼠重组P2 X7受体没有影响，嵌合P2 X7受体的研究表明SB-203580仅在含有人P2 X7受体N-末端255 aa的嵌合体中有效。SB-203580并不总是影响BzATP介导的细胞钙水平的增加，在电生理学研究中，它轻微降低了对30 μ M BzATP的反应，但增强了对100 μ M BzATP的反应。在THP 1细胞中，SB-203580适度抑制BzATP刺激的乙锭积累（pIC（50）5.7 - < 5），但SB-202190无影响。最后，SB-203580并没有阻止BzATP刺激的白细胞介素-1b释放THP-1 cells.Conclusions：这项研究证实，高浓度的SB-203580和SB-202190可以阻止人P2 X7受体介导的细胞乙锭积累的增加，但这是不相关的MAPK抑制。总体而言，这些数据对MAPK在介导P2 X7受体介导的细胞通透性变化中的一般作用产生了怀疑。
Background: Recent studies have implicated the mitogen activated protein kinase (MAPK) in cellular permeability changes following P2X(7) receptor activation in native tissues. In this study we have further studied the effect of MAPK inhibitors on recombinant and native P2X7 receptors.Experimental Approach: The MAPK inhibitors SB-203580, SB-202190 and SB-242235 were examined in HEK293 cells expressing recombinant P2X7 receptors and in THP-1 cells expressing native human P2X7 receptors using a range of experimental approaches.Key results: At human recombinant P2X7 receptors, SB-203580 and SB-202190 were weak, non-competitive inhibitors (pIC50 = 4.8-6.4) of ethidium accumulation stimulated by 2'- & 3'-O-(4benzoylbenzoyl)-ATP (BzATP) but SB-242235 (0.1-10 mu M) had no effect. SB-203580 and SB-202190 had no effect on rat or mouse recombinant P2X7 receptors and studies with chimeric P2X7 receptors suggested that SB-203580 was only effective in chimeras containing the N-terminal 255aa of the human P2X7 receptor. SB-203580 did not consistently affect BzATP-mediated increases in cell calcium levels and, in electrophysiological studies, it slightly decreased responses to 30 mu M BzATP but potentiated responses to 100 mu M BzATP. In THP1 cells, SB-203580 modestly inhibited BzATP-stimulated ethidium accumulation (pIC(50) 5.7 - < 5) but SB-202190 had no effect. Finally, SB-203580 did not block BzATP-stimulated interleukin-1b release in THP-1 cells.Conclusions: This study confirms that high concentrations of SB-203580 and SB-202190 can block human P2X7 receptor-mediated increases in cellular ethidium accumulation but suggest this is not related to MAPK inhibition. Overall, the data cast doubt on a general role of MAPK in mediating P2X7 receptor mediated changes in cellular permeability.