Extracellular oxidation by taurine chloramine activates ERK via the epidermal growth factor receptor
Extracellular oxidation by taurine chloramine activates ERK via the epidermal growth factor receptor
复制标题
DOI：
10.1074/jbc.m402070200
复制
发表时间：
2004-07-30
影响因子：
4.8
通讯作者：
Winterbourn, CC
中科院分区：
文献类型：
--
作者：
Midwinter, RG;Peskin, AV;Winterbourn, CC
牛磺酸以高浓度存在于中性粒细胞中，当细胞受到刺激时，牛磺酸可以与次氯酸(HOCl)反应生成牛磺酸氯胺(Tau-Cl)。这种化合物保留了氧化活性，可以影响中性粒细胞本身或周围的组织细胞。我们研究了Tau-Cl对人脐静脉内皮细胞(HUVEC)MAPK信号转导的影响。Tau-Cl没有引起细胞内谷胱甘肽的损失，也没有引起硫醇敏感酶甘油醛-3-磷酸脱氢酶的失活，表明它没有进入细胞。Tau-Cl(20-100微米)刺激HUVEC后，ERK在10min内迅速激活。这种激活被U0126抑制MEK而被取消，表明这不是因为ERK的直接氧化。未检测到p38的激活。这些结果表明，Tau-Cl与细胞膜靶标反应，导致细胞内ERK激活。在相同的浓度范围和时间范围内，Tau-Cl可刺激A431细胞和HUVEC的表皮生长因子(EGF)受体酪氨酸磷酸化。EGF受体抑制剂PD158780显著减弱Tau-Cl诱导的EGF受体和ERK的磷酸化。这表明EGF受体参与了ERK的上游激活。Src酪氨酸激酶抑制剂4-氨基-5-(4-氯苯基)-7-(叔丁基)吡唑醇[3，4-d]嘧啶对Tau-Cl诱导的EGF受体或ERK激活无影响。我们认为Tau-Cl作用于细胞表面的氧化敏感靶点，即EGF受体本身或另一个可以与EGF受体相互作用的靶点，从而激活ERK。
Taurine is present in high concentrations in neutrophils, and when the cells are stimulated taurine can react with hypochlorous acid (HOCl) to form taurine-chloramine (Tau-Cl). This compound retains oxidant activity and can affect the neutrophil itself or surrounding tissue cells. We have investigated the effects of Tau-Cl on MAPK signaling in human umbilical vein endothelial cells ( HUVEC). Tau-Cl caused no loss in intracellular glutathione or inactivation of the thiol-sensitive enzyme glyceral-dehyde-3-phosphate dehydrogenase, indicating that it had not entered the cells. However, stimulation of HUVEC with Tau-Cl (20-100 muM) induced the rapid activation of ERK within 10 min. This activation was abolished by inhibition of MEK by U0126, indicating that it was not because of direct oxidation of ERK. No activation of p38 was detected. These results suggest that Tau-Cl reacts with a cell membrane target that results in intracellular ERK activation. Tau-Cl over the same concentration range and time scale stimulated epidermal growth factor (EGF) receptor tyrosine phosphorylation in A431 cells and HUVEC. The EGF receptor inhibitor PD158780 significantly attenuated Tau-Cl-induced phosphorylation of both the EGF receptor and ERK. This implicates the EGF receptor in the upstream activation of ERK. The Src tyrosine kinase inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolol[3,4-d]pyrimidine had no effect on Tau-Cl-induced EGF receptor or ERK activation. We propose that Tau-Cl acts on an oxidant-sensitive target on the cell surface, this being either the EGF receptor itself or another target that can interact with the EGF receptor, with consequential activation of ERK.