Mechanism of Microbicidal Action of E-101 Solution, a Myeloperoxidase-Mediated Antimicrobial, and its Oxidative Products

ABSTRACTE-101 Solution is a first in class myeloperoxidase-mediated antimicrobial developed for topical application. It is composed of porcine myeloperoxidase (pMPO), glucose oxidase (GO), glucose, sodium chloride, and specific amino acids in an aqueous vehicle. Once activated, the reactive species hydrogen peroxide (H2O2), hypochlorous acid and singlet oxygen are generated. We evaluated the treatment effects of E-101 solution and its oxidative products on ultrastucture changes and microbicidal activity against methicillin-resistantStaphylococcus aureus(MRSA) andEscherichia coli. Time kill and transmission electron microscopy studies were performed using formulations with pMPO or GO omitted. The glutathione membrane protection assay was used to study the neutralization of reactive oxygen species. The potency of E-101 solution was also measured in the presence of serum and whole blood by MIC and MBC determinations. E-101 solution demonstrated rapid bactericidal activity and ultracellular changes in MRSA andE. colicells. When pMPO was omitted, high levels of H2O2generated from GO and glucose demonstrated slow microbicidal activity with minimal cellular damage. When GO was omitted from the formulation no antimicrobial activity or cellular damage was observed. Protection from exposure to E-101 solution reactive oxygen species in the glutathione protection assay was competitive and temporary. E-101 solution maintained its antimicrobial activity in the presence of inhibitory substances such as serum and whole blood. E-101 solution is a potent myeloperoxidase enzyme system with multiple oxidative mechanisms of action. Our findings suggest the primary site that E-101solution exerts microbicidal action is the cell membrane by inactivation of essential cell membrane components.

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Mechanism of Microbicidal Action of E-101 Solution, a Myeloperoxidase-Mediated Antimicrobial, and Its Oxidative Products

Infection and Immunity ◽

10.1128/iai.00261-19 ◽

2019 ◽

Vol 87 (7) ◽

Cited By ~ 1

Author(s):

Gerald A. Denys ◽

Neil C. Devoe ◽

Polyxeni Gudis ◽

Meghan May ◽

Robert C. Allen ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Antimicrobial Activity ◽

Cell Membrane ◽

Whole Blood ◽

Cellular Damage ◽

Oxygen Species ◽

Protection Assay ◽

Content Type ◽

Microbicidal Activity ◽

Oxidative Products

ABSTRACTE-101 solution is a first-in-class myeloperoxidase-mediated antimicrobial developed for topical application. It is composed of porcine myeloperoxidase (pMPO), glucose oxidase (GO), glucose, sodium chloride, and specific amino acids in an aqueous solution. Once activated, the reactive species hydrogen peroxide (H2O2), hypochlorous acid, and singlet oxygen are generated. We evaluated the treatment effects of E-101 solution and its oxidative products on ultrastructure changes and microbicidal activity against methicillin-resistantStaphylococcus aureus(MRSA) andEscherichia coli. Time-kill and transmission electron microscopy studies were also performed using formulations with pMPO or GO omitted. The glutathione membrane protection assay was used to study the neutralization of reactive oxygen species. The potency of E-101 solution was also measured in the presence of serum and whole blood by MIC and minimal bactericidal concentration (MBC) determinations. E-101 solution demonstrated rapid bactericidal activity and ultracellular changes in MRSA andE. colicells. When pMPO was omitted, high levels of H2O2generated from GO and glucose demonstrated slow microbicidal activity with minimal cellular damage. When GO was omitted from the formulation, no antimicrobial activity or cellular damage was observed. Protection from exposure to E-101 solution reactive oxygen species in the glutathione protection assay was competitive and temporary. E-101 solution maintained its antimicrobial activity in the presence of inhibitory substances, such as serum and whole blood. E-101 solution is a potent myeloperoxidase enzyme system with multiple oxidative mechanisms of action. Our findings suggest that the primary site where E-101 solution exerts microbicidal action is the cell membrane, by inactivation of essential cell membrane components.

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Efficacy of α-tocopherol administration in community-acquired pneumonia

Russian Pulmonology ◽

10.18093/0869-0189-2007-0-3-99-102 ◽

2007 ◽

pp. 99-102

Author(s):

F. R. Farkhutdinov

Keyword(s):

Reactive Oxygen Species ◽

Whole Blood ◽

Blood Concentration ◽

Conventional Treatment ◽

Clinical Course ◽

Reactive Oxygen ◽

Redox Status ◽

Community Acquired Pneumonia ◽

Oxygen Species ◽

Laboratory Parameters

We studied effect of α tocopherol on clinical course and production of reactive oxygen species (ROS) in the whole blood in patients with community acquired pneumonia (CAP). The trial involved 70 patients with CAP. Generation of ROS was studied using the luminol dependent chemilumines cence (LDCL) method. Conventional treatment was given to all the patients. Besides this, 35 patients received α tocopherol. LDCL intensity of the blood was enhanced in all the patients. Treatment with α-tocopherol decreased ROS blood concentration and resulted in positive dynamics of clini cal and laboratory parameters. By contrast, patients on the conventional treatment maintained high LDCL intensity and there was slowly resolved course of inflammation in many cases. So, α tocopherol improved redox status in patients with CAP and increased efficiency of the treatment.

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Human whole blood cells generate reactive oxygen species when exposed to iron oxide magnetic nanoparticles with different shells

Bulletin of Experimental Biology and Medicine ◽

10.47056/0365-9615-2021-171-1-95-99 ◽

2021 ◽

Vol 171 (1) ◽

pp. 95-99

Author(s):

Ya. G. Toropova ◽

◽

D. S. Motorina ◽

I. А. Zelinskaya ◽

D. V. Korolev ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Iron Oxide ◽

Magnetic Nanoparticles ◽

Whole Blood ◽

Blood Cells ◽

Reactive Oxygen ◽

Oxygen Species ◽

Human Whole Blood ◽

Iron Oxide Magnetic Nanoparticles ◽

Whole Blood Cells

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N-Acetyl cysteine abrogates silver-induced reactive oxygen species in human cells without altering silver-based antimicrobial activity

Toxicology Letters ◽

10.1016/j.toxlet.2020.07.014 ◽

2020 ◽

Vol 332 ◽

pp. 118-129

Author(s):

Kush N. Shah ◽

Parth N. Shah ◽

Andrew R. Mullen ◽

Qingquan Chen ◽

Marie R. Southerland ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Antimicrobial Activity ◽

Reactive Oxygen ◽

Human Cells ◽

Oxygen Species ◽

Acetyl Cysteine

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Cathelicidin Peptides Restrict Bacterial Growth via Membrane Perturbation and Induction of Reactive Oxygen Species

mBio ◽

10.1128/mbio.02021-19 ◽

2019 ◽

Vol 10 (5) ◽

Cited By ~ 5

Author(s):

Dean A. Rowe-Magnus ◽

Adenine Y. Kao ◽

Antonio Cembellin Prieto ◽

Meng Pu ◽

Cheng Kao

Keyword(s):

Reactive Oxygen Species ◽

Antimicrobial Peptides ◽

Single Cell ◽

Reactive Oxygen ◽

Cellular Damage ◽

Primary Effect ◽

Gram Negative Bacteria ◽

Oxygen Species ◽

Gram Positive ◽

Gram Negative

ABSTRACT All metazoans produce antimicrobial peptides (AMPs) that have both broad antimicrobial and immunomodulatory activity. Cathelicidins are AMPs that preferentially kill Gram-negative bacteria in vitro, purportedly by assembling into higher-order structures that perforate the membrane. We utilized high-resolution, single-cell fluorescence microscopy to examine their mechanism of action in real time. Engineered cathelicidins rapidly bound to Gram-negative and Gram-positive cells and penetrated the cytoplasmic membrane. Rapid failure of the peptidoglycan superstructure in regions of active turnover caused leakage of cytoplasmic contents and the formation of membrane-bound blebs. A mutation anticipated to destabilize interactions between cathelicidin subunits had no effect on bactericidal activity, suggesting that cathelicidins have activities beyond perforating the membrane. Nanomolar concentrations of cathelicidins, although not bactericidal, reduced the growth rate of Gram-negative and Gram-positive bacteria. The cells exhibited expression changes in multiple essential processes, including protein synthesis, peptidoglycan biosynthesis, respiration, and the detoxification of reactive oxygen species (ROS). Time-lapse imaging revealed that ROS accumulation preceded bleb formation, and treatments that reduced cellular ROS levels overcame these bactericidal effects. We propose that that the primary effect of cathelicidins is to induce the production of ROS that damage bacterial molecules, leading to slowed growth or cell death. Given their low circulating levels in vivo, AMPs may serve to slow bacterial population expansion so that cellular immunity systems can respond to and battle the infection. IMPORTANCE Antimicrobial peptides (AMPs) are an important part of the mammalian innate immune system in the battle against microbial infection. How AMPs function to control bacteria is not clear, as nearly all activity studies use nonphysiological levels of AMPs. We monitored peptide action in live bacterial cells over short time frames with single-cell resolution and found that the primary effect of cathelicidin peptides is to increase the production of oxidative molecules that cause cellular damage in Gram-positive and Gram-negative bacteria.

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