Influence of lipopolysaccharide-binding protein on pulmonary inflammation in gram-negative pneumonia.
Influence of lipopolysaccharide-binding protein on pulmonary inflammation in gram-negative pneumonia.
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DOI：
10.1097/shk.0000000000000349
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发表时间：
2015-06
期刊：
影响因子：
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通讯作者：
Hemmila MR
中科院分区：
文献类型：
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作者：
Taddonio MA;Dolgachev V;Bosmann M;Ward PA;Su G;Wang SC;Hemmila MR
脂多糖结合蛋白（LBP）作为急性期反应的一部分上调。LBP在增强革兰氏阴性菌的识别、清除和杀灭方面具有已知的多功能作用。在克雷伯氏菌肺炎模型中，我们先前证明，与野生型（Wt）小鼠相比，LBP-/-小鼠的死亡率增加（98 vs. 59%）。我们假设LBP是从肺中清除细菌所必需的，它的缺乏导致对肺炎的肺部炎症反应的改变。12 - 16周龄雌性C57 Bl/6 Wt小鼠和年龄匹配的LBP-/-小鼠通过腹膜内注射给予1×103菌落形成单位（CFU）的肺炎克雷伯氏菌。在接种后6、12、24或36小时对动物实施安乐死。获得肺组织和支气管肺泡灌洗样本。分析肺匀浆样品以确定每个全肺的定量细菌负荷、促炎细胞因子浓度、髓过氧化物酶活性和肺白细胞群体的评估。还在从Wt、Toll样受体4（TLR 4）-/-和LBP-/-小鼠分离的腹膜巨噬细胞的脂多糖刺激后测定炎症介质的体外产生。与野生型对照相比，LBP-/-小鼠在24和36小时时肺中的细菌水平显著升高。与Wt小鼠相比，LBP-/-小鼠中促炎细胞因子IL-1β、IL-6、KC和MIP-2的平均肺水平更高，并且保持升高的时间更长。在LBP-/-小鼠中，髓过氧化物酶活性（中性粒细胞含量的指标）在36小时时显著增加。LPS体外刺激腹腔巨噬细胞后，LBP-/-和TLR 4-/-小鼠IL-1β、IL-6、IL-10、KC和MIP-1α的产生受到抑制。功能性LBP基因的缺失导致革兰氏阴性菌从肺系统的清除减少。未能通过LBP/TLR 4轴识别和清除革兰氏阴性细菌导致初始延迟的炎症反应。LBP-/-小鼠的这种延迟随后是肺内促炎介质和中性粒细胞隔离的过度扩增和延长升高。
Lipopolysaccharide binding protein (LBP) is upregulated as part of the acute phase response. LBP has a known multifunctional role in potentiating the recognition, clearance, and killing of Gram-negative bacteria. In a Klebsiella pneumonia model we previously demonstrated that LBP-/- mice experience increased mortality when compared to wild-type (Wt) mice (98 vs. 59%). We hypothesize that LBP is essential to bacterial clearance from the lung and its absence leads to alteration of the pulmonary inflammatory response to pneumonia. 12 -16 week old female C57Bl/6 Wt mice and age matched LBP-/- mice were administered 1×103 colony forming units (CFU) of Klebsiella pneumoniae by intratracheal injection. Animals were euthanized at 6, 12, 24, or 36 hours post inoculation. Lung tissue and bronchoalveolar lavage samples were obtained. Lung homogenate samples were assayed to determine quantitative bacteria load per whole lung, proinflammatory cytokine concentrations, myeloperoxidase activity, and assessment of pulmonary leukocyte populations. In vitro production of inflammation mediators were also assayed following lipopolysaccharide stimulation of peritoneal macrophages isolated from Wt, Toll-like receptor 4 (TLR4)-/-, and LBP-/- mice. LBP-/- mice demonstrated significantly elevated levels of bacteria in the lung at 24 and 36 hours when compared to wild-type controls. The average lung levels of proinflammatory cytokines IL-1β, IL-6, KC, and MIP-2 were greater in the LBP-/- mice and remained elevated longer when compared to the Wt mice. Myeloperoxidase activity, an indicator of neutrophil content, was significantly increased at time 36 hours in the LBP-/- mice. Following in vitro stimulation of peritoneal macrophages with LPS, production of IL-1β, IL-6, IL-10, KC, and MIP-1α were suppressed in LBP-/- and TLR4-/- mice compared to Wt. Absence of a functional LBP gene results in diminished clearance of Gram-negative bacteria from the pulmonary system. Failure to recognize and clear Gram-negative bacteria via the LBP/TLR4 axis results in an initial delayed inflammatory response. This delay in LBP-/- mice is followed by excessive amplification and prolonged elevation of proinflammatory mediators and neutrophil sequestration within the lungs.