Methemoglobin is an endogenous toll-like receptor 4 ligand-relevance to subarachnoid hemorrhage.
Methemoglobin is an endogenous toll-like receptor 4 ligand-relevance to subarachnoid hemorrhage.
复制标题
高铁蛋白是一种内源性Toll样受体4配体与亚蛛网膜下腔出血。
DOI：
10.3390/ijms16035028
复制
发表时间：
2015-03-05
影响因子：
5.6
通讯作者：
Simard JM
中科院分区：
文献类型：
--
作者：
Kwon MS;Woo SK;Kurland DB;Yoon SH;Palmer AF;Banerjee U;Iqbal S;Ivanova S;Gerzanich V;Simard JM
神经炎症是蛛网膜下腔出血（SAH）的公认后果，可能是SAH重要并发症的原因。Toll样受体4（TLR 4）介导的小胶质细胞核因子κB（NFκB）信号转导在SAH后神经元损伤中起关键作用。三种来源于红细胞分解的分子被认为是内源性TLR 4配体：高铁血红蛋白（metHgb）、血红素和氯化血红素。然而，血红素和氯高铁血红素的水溶性差，以及脂多糖（LPS）的污染，已经混淆了我们对这些分子作为内源性TLR 4配体的理解。我们使用5步工艺获得了高度纯化的不含LPS的metHgb，这通过傅里叶变换离子回旋共振质谱和鲎变形细胞裂解物试验得到了证实。使用这种制备，我们表明，metHgb是TLR 4配体在生理相关浓度。metHgb引起小胶质细胞和巨噬细胞系中促炎细胞因子肿瘤坏死因子α（TNFα）的时间和剂量依赖性分泌，针对TLR 4的siRNA、TLR 4特异性抑制剂Rs-LPS和TAK-242以及抗CD 14抗体可抑制分泌。向大鼠蛛网膜下腔注射纯化的无LPS的metHgb诱导小胶质细胞活化和TNFα上调。总之，我们的研究结果支持了SAH后，蛛网膜下腔的metHgb可促进广泛的TLR 4介导的神经炎症的假设。
Neuroinflammation is a well-recognized consequence of subarachnoid hemorrhage (SAH), and may be responsible for important complications of SAH. Signaling by Toll-like receptor 4 (TLR4)-mediated nuclear factor κB (NFκB) in microglia plays a critical role in neuronal damage after SAH. Three molecules derived from erythrocyte breakdown have been postulated to be endogenous TLR4 ligands: methemoglobin (metHgb), heme and hemin. However, poor water solubility of heme and hemin, and lipopolysaccharide (LPS) contamination have confounded our understanding of these molecules as endogenous TLR4 ligands. We used a 5-step process to obtain highly purified LPS-free metHgb, as confirmed by Fourier Transform Ion Cyclotron Resonance mass spectrometry and by the Limulus amebocyte lysate assay. Using this preparation, we show that metHgb is a TLR4 ligand at physiologically relevant concentrations. metHgb caused time- and dose-dependent secretion of the proinflammatory cytokine, tumor necrosis factor α (TNFα), from microglial and macrophage cell lines, with secretion inhibited by siRNA directed against TLR4, by the TLR4-specific inhibitors, Rs-LPS and TAK-242, and by anti-CD14 antibodies. Injection of purified LPS-free metHgb into the rat subarachnoid space induced microglial activation and TNFα upregulation. Together, our findings support the hypothesis that, following SAH, metHgb in the subarachnoid space can promote widespread TLR4-mediated neuroinflammation.
登录
查看更多内容
DOI：
10.1038/jcbfm.2010.137
发表时间：
2010-11
期刊：
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
影响因子：
--
作者：
通讯作者：
--
影响因子：
6.9
作者：
Fujii, Mutsumi;Yan, Junhao;Rolland, William B.;Soejima, Yoshiteru;Caner, Basak;Zhang, John H.
通讯作者：
Zhang, John H.
影响因子：
4.1
作者：
Jerala, Roman
通讯作者：
Jerala, Roman
影响因子：
8.3
作者：
Fassbender, K;Hodapp, B;Hennerici, M
通讯作者：
Hennerici, M
影响因子：
4.8
作者：
Gao, BC;Tsan, MF
通讯作者：
Tsan, MF