Molecular characterization of TRPA1 channel activation by cysteine-reactive inflammatory mediators
Molecular characterization of TRPA1 channel activation by cysteine-reactive inflammatory mediators
复制标题
DOI：
10.4161/chan.2.4.6745
复制
发表时间：
2008-07-01
期刊：
影响因子：
3.3
通讯作者：
Mori, Yasuo
中科院分区：
文献类型：
--
作者：
Takahashi, Nobuaki;Mizuno, Yusuke;Mori, Yasuo
TRPA 1是瞬时受体电位（TRP）阳离子通道家族的成员，主要表达于背根神经节（DRG）和三叉神经节的伤害感受神经元。环境刺激物如芥子油、大蒜素和丙烯醛激活TRPA 1可引起急性疼痛。然而，直接激活TRPA 1的内源性配体在炎症中仍然难以捉摸。在这里，我们发现多种炎症介质（15-脱氧-Delta（12，14）-前列腺素J（2）（15 d-PGJ（2）），一氧化氮（NO），过氧化氢（H2 O2）和质子（H+））激活HEK细胞中异源表达的人TRPA 1。这些炎症介质诱导小鼠DRG神经元亚群中的强Ca 2+内流。TRP通道阻断剂钌红几乎完全抑制15 d-PGJ_2和NO引起的神经元反应，但部分抑制H_2O_2和H ~+引起的反应。TRPA 1定点半胱氨酸突变体的功能表征结合使用生物素化15 d-PGJ 2的标记实验证明，细胞质N-末端半胱氨酸（Cys 421和Cys 621）的修饰是15 d-PGJ激活TRPA 1的原因（2）。在TRPA 1对其他半胱氨酸反应性炎症介质（如NO和H2 O2）的反应中，相应半胱氨酸突变的损伤程度与TRPA 1对15 d-PGJ的反应不同（2）。有趣的是，Cys 421突变也严重损害了TRPA 1对H+的反应。我们的研究结果表明，TRPA 1通道的目标是由一系列的炎症介质，以引起神经系统中的炎性疼痛。
TRPA1 is a member of the transient receptor potential (TRP) cation channel family, and is predominantly expressed in nociceptive neurons of dorsal root ganglia (DRG) and trigeminal ganglia. Activation of TRPA1 by environmental irritants such as mustard oil, allicin and acrolein causes acute pain. However, the endogenous ligands that directly activate TRPA1 remain elusive in inflammation. Here, we show that a variety of inflammatory mediators (15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), nitric oxide (NO), hydrogen peroxide (H2O2), and proton (H+)) activate human TRPA1 heterologously expressed in HEK cells. These inflammatory mediators induced robust Ca2+ influx in a subset of mouse DRG neurons. The TRP channel blocker ruthenium red almost completely inhibited neuronal responses by 15d-PGJ2 and NO, but partially suppressed responses to H2O2 and H+. Functional characterization of site-directed cysteine mutants of TRPA1 in combination with labeling experiments using biotinylated 15d-PGJ2 demonstrated that modifications of cytoplasmic N-terminal cysteines (Cys421 and Cys621) were responsible for the activation of TRPA1 by 15d-PGJ(2). In TRPA1 responses to other cysteine-reactive inflammatory mediators, such as NO and H2O2, the extent of impairment by respective cysteine mutations differed front those in TRPA1 responses to 15d-PGJ(2). Interestingly, the Cys421 mutation critically impaired the TRPA1 response to H+ as well. Our findings suggest that TRPA1 channels are targeted by an array of inflammatory mediators to elicit inflammatory pain in the nervous system.