Tissue kallikrein protects neurons from hypoxia/reoxygenation-induced cell injury through Homer1b/c
Tissue kallikrein protects neurons from hypoxia/reoxygenation-induced cell injury through Homer1b/c
复制标题
组织激肽释放酶通过 Homer1b/c 保护神经元免受缺氧/复氧诱导的细胞损伤
DOI：
10.1016/j.cellsig.2012.04.021
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发表时间：
2012-11-01
影响因子：
4.8
通讯作者：
Dong, Qiang
中科院分区：
文献类型：
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作者：
Su, Jingjing;Tang, Yuping;Dong, Qiang
以往的研究表明，人组织激肽释放酶(TM)基因传递通过激活缓激肽B2受体(B2R)对小鼠脑缺血再灌注(I/R)损伤具有保护作用。我们还报道，外源性TM可以通过细胞外信号调节激酶1/2(ERK1/2)途径抑制谷氨酸或酸中毒诱导的神经毒性。为了进一步探讨TM的神经保护机制，在本研究中，我们进行了免疫沉淀分析，并利用MALDI-TOF MS分析鉴定了支架蛋白Hmer 1b/c。在这里，我们验证了TK通过激活Hmer 1b/c来减轻缺氧和葡萄糖剥夺/复氧(OGD/R)引起的细胞损伤的假设。我们发现TK以浓度和时间依赖的方式增加Hmer 1b/c的表达。此外，在OGD/R条件下，通过共聚焦显微镜分析，TK促进了Hmer 1b/c向质膜的移位。我们还观察到Hmer 1b/c的过表达通过提高细胞存活率、减少LDH释放、caspase-3活性和细胞凋亡而对OGD/R诱导的细胞损伤具有神经保护作用。而小干扰RNA对Hmer 1b/c的抑制作用则相反，表明Hmer 1b/c对OGD/R诱导的神经元损伤具有保护作用。更有趣的是，TM在Hmer 1b/c过表达后发挥了更显著的神经保护作用，而在Hmer 1b/c被敲除后则发挥了减弱的作用。此外。TM通过激活Hmer 1b/c增加ERK1/2和Akt-GSK3β的磷酸化。ERK1/2或PI3K拮抗剂可消除Hmer 1b/c的有利作用。因此，我们提出了通过激活Hmer 1b/c-ERK1/2和Hmer 1b/c-PI3K-Akt信号通路参与TM抗缺氧作用的新的信号机制。(C)2012 Elsevier Inc.保留所有权利。
Previous studies have demonstrated that human tissue kallikrein (TM) gene delivery protects against mouse cerebral ischemia/reperfusion (I/R) injury through bradykinin B2 receptor (B2R) activation. We have also reported that exogenous TM administration can suppress glutamate- or acidosis-induced neurotoxicity through the extracellular signal-regulated kinase1/2 (ERK1/2) pathway. To further explore the neuroprotection mechanisms of TM, in the present study we performed immunoprecipitation analysis and identified a scaffolding protein Homer1b/c using MALDI-TOF MS analysis. Here, we tested the hypothesis that TK reduces cell injury induced by oxygen and glucose deprivation/reoxygenation (OGD/R) through activating Homer1b/c. We found that TK increased the expression of Homer1b/c in a concentration- and time-dependent manner. Moreover, TK facilitated the translocation of Homer1b/c to the plasma membrane under OGD/R condition by confocal microscope assays. We also observed that overexpression of Homer1b/c showed the neuroprotection against OGD/R-induced cell injury by enhancing cell survival, reducing LDH release, caspase-3 activity and cell apoptosis. However, the knockdown of Homer1b/c by small interfering RNA showed the opposite effects, indicating that Homer1b/c had protective effects against OGD/R-induced neuronal injury. More interestingly, TM exerted its much more significantly neuroprotective effects after Homer1b/c overexpression, whereas it exerted its reduced effects after Homer1b/c knockdown. In addition. TM pretreatment increased the phosphorylation of the ERK1/2 and Akt-GSK3 beta, through Homer1b/c activation. The beneficial effects of Homer1b/c were abolished by the ERK1/2 or PI3K antagonist. Therefore, we propose novel signaling mechanisms involved in the anti-hypoxic function of TM through activation of Homer1b/c-ERK1/2 and Homer1b/c-PI3K-Akt signaling pathways. (C) 2012 Elsevier Inc. All rights reserved.