LPS-mediated endothelial activation in pulmonary endothelial cells: role of Nox2-dependent IKK-β phosphorylation
LPS-mediated endothelial activation in pulmonary endothelial cells: role of Nox2-dependent IKK-β phosphorylation
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DOI：
10.1152/ajplung.00261.2012
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发表时间：
2013-03-01
影响因子：
4.9
通讯作者：
Sampath, Venkatesh
中科院分区：
文献类型：
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作者：
Menden, Heather;Tate, Everett;Sampath, Venkatesh
Menden H，Tate E，Hogg N，Sampath V.肺内皮细胞中LPS介导的内皮活化：Nox 2依赖性IKK-β磷酸化的作用。Am J Physiol Lung Cell Mol Physiol 304：L445-L455，2013.首次发表于2013年1月18日; doi：10.1152/ajplung.00261.2012.-脂多糖（LPS）介导的内皮细胞活化有助于支气管肺发育不良（BPD）早产儿的肺部炎症和肺泡重塑。人肺微血管内皮细胞（HPMEC）中LPS介导的氧化应激和促炎信号转导的机制尚不清楚。我们假设NADPH氧化酶（Nox）通过调节Toll样受体（TLR）通路蛋白的磷酸化来介导LPS诱导的HPMEC内皮活化。LPS诱导的细胞间粘附分子1（ICAM-1）的表达与2-OH-E+（超氧化物形成的标志物）水平增加有关，并被夹竹桃苷和Nox抑制剂VAS 2870减弱。LPS触发p67 phox的膜转位，表明Nox 2的激活。沉默Nox 2而非Nox 4可抑制LPS诱导的HPMEC中ICAM-1的表达。免疫沉淀研究表明，Nox 2沉默抑制LPS诱导的IKK-β丝氨酸磷酸化抑制剂。我们检测了HPMEC中Nox 2依赖性、LPS介导的IKK-β磷酸化是否受蛋白磷酸酶2A（PP 2A）或TGF-β相关激酶-1（TAK 1）的调节。LPS增加HPMEC中PP 2A活性，抑制PP 2A不改变LPS介导的ICAM-1表达，但减弱IKK-β磷酸化。TAK 1抑制降低LPS诱导的HPMEC中ICAM-1表达，Nox 2沉默减弱LPS介导的TAK 1磷酸化（Thr 184/187）。我们证明，Nox 2调节LPS介导的肺内皮细胞的内皮细胞活化，通过调节TLR信号级联的关键激酶的磷酸化。我们的数据支持一种新的机制，通过这种机制，Nox依赖性信号调节肺内皮细胞的促炎信号。抑制血管Nox可能潜在地限制BPD感染引起的肺损伤和肺泡重塑。
Menden H, Tate E, Hogg N, Sampath V. LPS-mediated endothelial activation in pulmonary endothelial cells: role of Nox2-dependent IKK-beta phosphorylation. Am J Physiol Lung Cell Mol Physiol 304: L445-L455, 2013. First published January 18, 2013; doi:10.1152/ajplung.00261.2012.-Lipopolysaccharide (LPS)-mediated endothelial activation contributes to lung inflammation and alveolar remodeling seen in premature infants with bronchopulmonary dysplasia (BPD). The mechanisms underlying LPS-mediated oxidative stress and proinflammatory signaling in human pulmonary microvascular endothelial cells (HPMEC) remain unclear. We hypothesized that NADPH oxidase (Nox) mediates LPS-induced endothelial activation in HPMEC by regulating phosphorylation of Toll-like receptor (TLR) pathway proteins. LPS-induced expression of intercellular adhesion molecule 1 (ICAM-1) was associated with increased 2-OH-E+ (marker for superoxide formation) levels and was attenuated by apocynin and the Nox inhibitor, VAS2870. LPS triggered membrane translocation of p67phox, suggesting activation of Nox2. Silencing Nox2, but not Nox4, suppressed LPS-induced ICAM-1 expression in HPMEC. Immunoprecipitation studies showed that inhibitor of kappa-B kinase-beta (IKK-beta) serine phosphorylation induced by LPS was inhibited by Nox2 silencing. We examined whether Nox2-dependent, LPS-mediated IKK-beta phosphorylation was regulated by protein phosphatase 2A (PP2A) or TGF-beta associated kinase-1 (TAK1) in HPMEC. LPS increased PP2A activity in HPMEC, and inhibition of PP2A did not alter LPS-mediated ICAM-1 expression but attenuated IKK-beta phosphorylation. TAK1 inhibition decreased LPS-induced ICAM-1 expression in HPMEC, and Nox2 silencing attenuated LPS-mediated TAK1 phosphorylation (Thr184/187). We demonstrate that Nox2 regulates LPS-mediated endothelial activation in pulmonary endothelial cells by modulating phosphorylation of key kinases in the TLR signaling cascade. Our data support a novel mechanism by which Nox-dependent signaling regulates proinflammatory signaling in pulmonary endothelial cells. Inhibition of vascular Nox may potentially limit lung injury and alveolar remodeling caused by infections in BPD.