Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, Birmingham, Alabama, USA.
Microbiol Spectr. 2022 Feb 23;10(1):e0052221. doi: 10.1128/spectrum.00522-21. Epub 2022 Jan 12.
Heme-containing peroxidases are widely distributed in the animal and plant kingdoms and play an important role in host defense by generating potent oxidants. Myeloperoxidase (MPO), the prototype of heme-containing peroxidases, exists in neutrophils and monocytes. MPO has a broad spectrum of microbial killing. The difficulty of producing MPO at a large scale hinders its study and utilization. This study aimed to overexpress recombinant human MPO and characterize its microbicidal activities and . A human HEK293 cell line stably expressing recombinant MPO (rMPO) was established as a component of this study. rMPO was overexpressed and purified for studies on its biochemical and enzymatic properties, as well as its microbicidal activities. In this study, rMPO was secreted into culture medium as a monomer. rMPO revealed enzymatic activity similar to that of native MPO. rMPO, like native MPO, was capable of killing a broad spectrum of microorganisms, including Gram-negative and -positive bacteria and fungi, at low nM levels. Interestingly, rMPO could kill antibiotic-resistant bacteria, making it very useful for treatment of nosocomial infections and mixed infections. The administration of rMPO significantly reduced the morbidity and mortality of murine lung infections induced by Pseudomonas aeruginosa or methicillin-resistant Staphylococcus aureus. In animal safety tests, the administration of 100 nM rMPO via tail vein did not result in any sign of toxic effects. Taken together, the data suggest that rMPO purified from a stably expressing human cell line is a new class of antimicrobial agents with the ability to kill a broad spectrum of pathogens, including bacteria and fungi with or without drug resistance. Over the past 2 decades, more than 20 new infectious diseases have emerged. Unfortunately, novel antimicrobial therapeutics are discovered at much lower rates. Infections caused by resistant microorganisms often fail to respond to conventional treatment, resulting in prolonged illness, greater risk of death, and high health care costs. Currently, this is best seen with the lack of a cure for coronavirus disease 2019 (COVID-19). To combat such untreatable microorganisms, there is an urgent need to discover new classes of antimicrobial agents. Myeloperoxidase (MPO) plays an important role in host defense. The difficulty of producing MPO on a large scale hinders its study and utilization. We have produced recombinant MPO at a large scale and have characterized its antimicrobial activities. Most importantly, recombinant MPO significantly reduced the morbidity and mortality of murine pneumonia induced by Pseudomonas aeruginosa or methicillin-resistant Staphylococcus aureus. Our data suggest that recombinant MPO from human cells is a new class of antimicrobials with a broad spectrum of activity.
含血红素过氧化物酶广泛存在于动植物界，通过产生有效的氧化剂在宿主防御中发挥重要作用。髓过氧化物酶 (MPO) 是血红素过氧化物酶的原型，存在于中性粒细胞和单核细胞中。MPO 具有广谱的微生物杀灭作用。大规模生产 MPO 的困难阻碍了其研究和利用。本研究旨在过表达重组人 MPO 并表征其杀菌活性。
作为本研究的一部分，建立了稳定表达重组 MPO(rMPO)的人 HEK293 细胞系。rMPO 被大量表达和纯化，用于研究其生化和酶特性以及杀菌活性。在本研究中，rMPO 作为单体分泌到培养基中。rMPO 显示出与天然 MPO 相似的酶活性。rMPO 与天然 MPO 一样，能够以低 nM 水平杀死广谱微生物，包括革兰氏阴性和阳性细菌以及真菌。有趣的是，rMPO 可以杀死抗生素耐药菌，使其非常适合治疗医院获得性感染和混合感染。rMPO 的给药显著降低了铜绿假单胞菌或耐甲氧西林金黄色葡萄球菌诱导的小鼠肺部感染的发病率和死亡率。在动物安全性测试中，尾静脉注射 100 nM rMPO 不会导致任何毒性迹象。
综上所述，从稳定表达的人细胞系中纯化的 rMPO 是一类新的抗菌剂，具有杀死广谱病原体的能力，包括有或没有耐药性的细菌和真菌。
在过去的 20 年中，出现了 20 多种新的传染病。不幸的是，新型抗菌治疗药物的发现速度要慢得多。由耐药微生物引起的感染通常对常规治疗无反应，导致病程延长、死亡风险增加和医疗保健费用增加。目前，这在缺乏 2019 年冠状病毒病 (COVID-19) 治疗方法方面表现得最为明显。为了对抗这些无法治疗的微生物，迫切需要发现新的抗菌剂类别。髓过氧化物酶 (MPO) 在宿主防御中起重要作用。大规模生产 MPO 的困难阻碍了其研究和利用。我们已经大规模生产了重组 MPO，并对其抗菌活性进行了表征。最重要的是，重组 MPO 显著降低了铜绿假单胞菌或耐甲氧西林金黄色葡萄球菌诱导的小鼠肺炎的发病率和死亡率。我们的数据表明，来自人细胞的重组 MPO 是一类具有广谱活性的新型抗菌剂。
