Mannheimia haemolytica and Its Leukotoxin Cause Macrophage Extracellular Trap Formation by Bovine Macrophages
Mannheimia haemolytica and Its Leukotoxin Cause Macrophage Extracellular Trap Formation by Bovine Macrophages
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DOI：
10.1128/iai.06120-11
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发表时间：
2012-05-01
影响因子：
3.1
通讯作者：
Czuprynski, Charles J.
中科院分区：
文献类型：
--
作者：
Aulik, Nicole A.;Hellenbrand, Katrina M.;Czuprynski, Charles J.
人和牛的中性粒细胞释放中性粒细胞胞外陷阱（NET），这是一种能够在胞外捕获和杀死病原体的蛋白质镶嵌的DNA基质。最近，我们报道了牛中性粒细胞释放NET以响应重要的呼吸道病原体溶血性曼海姆菌及其白细胞毒素（LKT）。在这里，我们证明了巨噬细胞胞外陷阱（MET）的形成，由牛单核细胞衍生的巨噬细胞暴露于M。溶血性或其LKT。天然的完全活性LKT和非细胞溶解的pro-LKT（由M.溶血性）刺激MET形成。共聚焦和扫描电子显微镜揭示了一个网络的DNA纤维与共定位的组蛋白在细胞外陷阱释放牛巨噬细胞。MET的形成需要NADPH氧化酶活性，如先前NET形成所示。MET是对LKT的反应，它捕获并杀死了一部分M。溶血细胞牛肺泡巨噬细胞，而不是外周血单核细胞，也形成MET响应M。溶血细胞MET形成不限于牛巨噬细胞。我们还观察到MET形成的小鼠巨噬细胞系RAW 264.7和人THP-1细胞衍生的巨噬细胞，大肠杆菌溶血素的反应。后者是与M.溶血性白细胞毒素这项研究表明，巨噬细胞，像中性粒细胞，可以形成细胞外陷阱，以应对细菌病原体及其外毒素。
Human and bovine neutrophils release neutrophil extracellular traps (NETs), which are protein-studded DNA matrices capable of extracellular trapping and killing of pathogens. Recently, we reported that bovine neutrophils release NETs in response to the important respiratory pathogen Mannheimia haemolytica and its leukotoxin (LKT). Here, we demonstrate macrophage extracellular trap (MET) formation by bovine monocyte-derived macrophages exposed to M. haemolytica or its LKT. Both native fully active LKT and noncytolytic pro-LKT (produced by an lktC mutant of M. haemolytica) stimulated MET formation. Confocal and scanning electron microscopy revealed a network of DNA fibrils with colocalized histones in extracellular traps released from bovine macrophages. Formation of METs required NADPH oxidase activity, as previously demonstrated for NET formation. METs formed in response to LKT trapped and killed a portion of the M. haemolytica cells. Bovine alveolar macrophages, but not peripheral blood monocytes, also formed METs in response to M. haemolytica cells. MET formation was not restricted to bovine macrophages. We also observed MET formation by the mouse macrophage cell line RAW 264.7 and by human THP-1 cell-derived macrophages, in response to Escherichia coli hemolysin. The latter is a member of the repeats-in-toxin (RTX) toxin family related to the M. haemolytica leukotoxin. This study demonstrates that macrophages, like neutrophils, can form extracellular traps in response to bacterial pathogens and their exotoxins.