Neutrophils exposed to bacterial lipopolysaccharide upregulate NADPH oxidase assembly
Neutrophils exposed to bacterial lipopolysaccharide upregulate NADPH oxidase assembly
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DOI：
10.1172/jci949
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发表时间：
1998-01-15
影响因子：
15.9
通讯作者：
Nauseef, WM
中科院分区：
文献类型：
--
作者：
DeLeo, FR;Renee, J;Nauseef, WM
细菌内毒素是中性粒细胞的多功能激动剂。尽管脂多糖不能直接激活依赖NADPH的氧化酶，但它能使中性粒细胞对其他刺激更敏感，这一现象被称为“启动”。由于内毒素依赖的启动机制还不完全清楚，我们研究了它对NADPH氧化酶组装和激活的影响。脂多糖预处理使超氧化物(O-2(-))的生成增加近10倍，以响应N-甲酰甲硫基亮氨酰苯丙氨酸(FMLP)。在破碎的细胞O-2(-)生成系统中，内毒素处理的细胞富含质膜的部分活性增加，而特定的富含颗粒的部分活性降低。氧化还原光谱分析和流式细胞仪分析表明，脂多糖增加了黄色素b的质膜结合(558)。脂多糖处理的中性粒细胞质膜囊泡的免疫印迹显示p47-Phox易位，但不显示p67-Phox或rac2的易位。然而，经LPS和fMLP连续处理的PMN显示，质膜相关的p47-Phox、p67-Phox和rac2的表达增加了3-6倍(与任一种单独处理相比)，并且移位平行增加了完整PMN的O-2(-)生成。与PMA处理的细胞相比，LPS和/或fMLP处理的细胞质膜富集组分含有更少的P47-Phox的酸性物种。综上所述，这些研究表明，NADPH氧化酶组分的重新分布可能是内毒素引发呼吸爆发的基础。
Bacterial LPS is a pluripotent agonist for PMNs. Although it does not activate the NADPH-dependent oxidase directly, LPS renders PMNs more responsive to other stimuli, a phenomenon known as "priming." Since the mechanism of LPS-dependent priming is incompletely understood, we investigated its effects on assembly and activation of the NADPH oxidase. LPS pretreatment increased superoxide (O-2(-)) generation nearly 10-fold in response to N-formyl methionyl leucyl phenylalanine (fMLP). In a broken-cell O-2(-)-generating system, activity was increased in plasma membrane-rich fractions and concomitantly decreased in specific granule-rich fractions from LPS-treated cells. Oxidation-reduction spectroscopy and flow cytometry indicated LPS increased plasma membrane association of flavocytochrome b(558). Immunoblots of plasma membrane vesicles from LPS-treated PMNs demonstrated translocation of p47-phox but not of p67-phox or Rac2. However, PMNs treated sequentially with LPS and fMLP showed a three-to sixfold increase (compared with either agent alone) in plasma membrane-associated p47-phox, p67-phox, and Rac2, and translocation paralleled augmented O-2(-) generation by intact PMNs. LPS treatment caused limited phosphorylation of p47-phox, and plasma membrane-enriched fractions from LPS- and/or fMLP-treated cells contained fewer acidic species of p47-phox than did those from cells treated with PMA. Taken together, these studies suggest that redistribution of NADPH oxidase components may underlie LPS priming of the respiratory burst.