Myeloperoxidase associated with neutrophil extracellular traps is active and mediates bacterial killing in the presence of hydrogen peroxide
Myeloperoxidase associated with neutrophil extracellular traps is active and mediates bacterial killing in the presence of hydrogen peroxide
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DOI：
10.1189/jlb.0711387
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发表时间：
2012-03-01
影响因子：
5.5
通讯作者：
Winterbourn, Christine C.
中科院分区：
文献类型：
--
作者：
Parker, Heather;Albrett, Amelia M.;Winterbourn, Christine C.
多种炎症刺激诱导NET。这些结构由与主要颗粒蛋白（包括MPO）相关的染色质链网络组成。NET表现出抗微生物活性，这被认为是为了增强更成熟的吞噬体杀伤机制。在慢性炎症或严重脓毒症等情况下，它们也可能对宿主有害。本研究的目的是确定与NET相关的MPO是否具有活性并能够杀死细菌。用PMA刺激中性粒细胞以释放NET。进行过氧化物酶活性测定，结果显示，刺激后2-4 h，伴随NET形成，中性粒细胞释放酶活性MPO。约30%的总细胞MPO被释放，其中大部分结合到NET。结合的酶保留了其活性。在我们的测定条件下，当添加到预先形成的NET中时，金黄色葡萄球菌没有被杀死。然而，在NET存在下向细菌中加入H2 O2导致MPO依赖性杀伤，这在NET原位和NET通过有限的DNA酶消化从中性粒细胞中去除时观察到。我们的研究结果表明，MPO对NET的酶活性可能有助于抗菌活性或组织损伤时，NET从感染或炎症部位的中性粒细胞释放。J. Leukoc. 91：369-376; 2012.
A variety of inflammatory stimuli induces NETs. These structures consist of a network of chromatin strands associated with predominately granule proteins, including MPO. NETs exhibit antimicrobial activity, which is proposed to augment the more-established mechanism of phagosomal killing. They may also be detrimental to the host in situations such as chronic inflammation or severe sepsis. The objective of this study was to establish whether MPO associated with NETs is active and able to kill bacteria. Neutrophils were stimulated with PMA to release NETs. Peroxidase activity measurements were performed and showed that enzymatically active MPO was released from the neutrophils, 2-4 h after stimulation, concomitant with NET formation. Approximately 30% of the total cellular MPO was released, with the majority bound to the NETs. The bound enzyme retained its activity. Staphylococcus aureus were not killed when added to preformed NETs under our assay conditions. However, addition of H2O2 to the bacteria in the presence of NETs resulted in MPO-dependent killing, which was observed with NETs in situ and with NETs when they were removed from the neutrophils by limited DNase digestion. Our results show that the enzymatic activity of MPO on NETs could contribute to antimicrobial activity or tissue injury when NETs are released from neutrophils at sites of infection or inflammation. J. Leukoc. Biol. 91: 369-376; 2012.