PDF(Pubmed)
Abstract：
Neutrophil extracellular traps (NETs) are networks of DNA and various microbicidal proteins released to kill invading microorganisms and prevent their dissemination. However, a NETs excess is detrimental to the host and involved in the pathogenesis of various inflammatory and immunothrombotic diseases. Clostridium perfringens is a widely distributed pathogen associated with several animal and human diseases, that produces many exotoxins, including the phospholipase C (CpPLC), the main virulence factor in gas gangrene. During this disease, CpPLC generates the formation of neutrophil/platelet aggregates within the vasculature, favoring an anaerobic environment for C. perfringens growth. This work demonstrates that CpPLC induces NETosis in human neutrophils. Antibodies against CpPLC completely abrogate the NETosis-inducing activity of recombinant CpPLC and C. perfringens secretome. CpPLC induces suicidal NETosis through a mechanism that requires calcium release from inositol trisphosphate receptor (IP3) sensitive stores, activation of protein kinase C (PKC), and the mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) pathways, as well as the production of reactive oxygen species (ROS) by the metabolism of arachidonic acid. Proteomic analysis of the C. perfringens secretome identified 40 proteins, including a DNAse and two 5´-nucleotidases homologous to virulence factors that could be relevant in evading NETs. We suggested that in gas gangrene this pathogen benefits from having access to the metabolic resources of the tissue injured by a dysregulated intravascular NETosis and then escapes and spreads to deeper tissues. Understanding the role of NETs in gas gangrene could help develop novel therapeutic strategies to reduce mortality, improve muscle regeneration, and prevent deleterious patient outcomes.
摘要：
中性粒细胞胞外诱捕器(NETs)是释放的DNA和各种杀微生物蛋白的网络,以杀死入侵的微生物并防止其传播。然而,过量的NETs对宿主是有害的,并且涉及各种炎症和免疫血栓形成疾病的发病机理。产气荚膜梭菌是一种广泛分布的病原体，与几种动物和人类疾病有关。产生许多外毒素，包括磷脂酶C（CpPLC），气体坏疽的主要毒力因子。在这种疾病期间，CpPLC在脉管系统内产生中性粒细胞/血小板聚集体的形成，有利于产气荚膜梭菌生长的厌氧环境。这项工作证明CpPLC在人嗜中性粒细胞中诱导NETosis。针对CpPLC的抗体完全消除了重组CpPLC和产气荚膜梭菌分泌组的NETosis诱导活性。CpPLC通过一种需要从三磷酸肌醇受体（IP3）敏感存储中释放钙的机制诱导自杀性NETosis，蛋白激酶C（PKC）的激活，和丝裂原活化蛋白激酶/细胞外信号调节激酶（MEK/ERK）途径，以及通过花生四烯酸代谢产生活性氧（ROS）。产气荚膜梭菌分泌组的蛋白质组学分析鉴定出40种蛋白质，包括与逃避NETs相关的毒力因子同源的DNA酶和两个5'-核苷酸酶。我们建议，在气体坏疽中，这种病原体受益于获得因血管内NETosis失调而受伤的组织的代谢资源，然后逃逸并扩散到更深的组织。了解NETs在气体坏疽中的作用可以帮助开发新的治疗策略来降低死亡率。改善肌肉再生，并防止有害的患者结果。
