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Lin W, Chen H, Chen X, Guo C. The Roles of Neutrophil-Derived Myeloperoxidase (MPO) in Diseases: The New Progress. Antioxidants (Basel) 2024; 13:132. [PMID: 38275657 PMCID: PMC10812636 DOI: 10.3390/antiox13010132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/06/2024] [Accepted: 01/12/2024] [Indexed: 01/27/2024] Open
Abstract
Myeloperoxidase (MPO) is a heme-containing peroxidase, mainly expressed in neutrophils and, to a lesser extent, in monocytes. MPO is known to have a broad bactericidal ability via catalyzing the reaction of Cl- with H2O2 to produce a strong oxidant, hypochlorous acid (HOCl). However, the overproduction of MPO-derived oxidants has drawn attention to its detrimental role, especially in diseases characterized by acute or chronic inflammation. Broadly speaking, MPO and its derived oxidants are involved in the pathological processes of diseases mainly through the oxidation of biomolecules, which promotes inflammation and oxidative stress. Meanwhile, some researchers found that MPO deficiency or using MPO inhibitors could attenuate inflammation and tissue injuries. Taken together, MPO might be a promising target for both prognostic and therapeutic interventions. Therefore, understanding the role of MPO in the progress of various diseases is of great value. This review provides a comprehensive analysis of the diverse roles of MPO in the progression of several diseases, including cardiovascular diseases (CVDs), neurodegenerative diseases, cancers, renal diseases, and lung diseases (including COVID-19). This information serves as a valuable reference for subsequent mechanistic research and drug development.
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Affiliation(s)
- Wei Lin
- Clinical Pharmacology Research Center, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China;
| | - Huili Chen
- Center of System Pharmacology and Pharmacometrics, College of Pharmacy, University of Florida, Gainesville, FL 32611, USA;
| | - Xijing Chen
- Clinical Pharmacology Research Center, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China;
| | - Chaorui Guo
- Clinical Pharmacology Research Center, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China;
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2
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Khramova YV, Katrukha VA, Chebanenko VV, Kostyuk AI, Gorbunov NP, Panasenko OM, Sokolov AV, Bilan DS. Reactive Halogen Species: Role in Living Systems and Current Research Approaches. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:S90-S111. [PMID: 38621746 DOI: 10.1134/s0006297924140062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/21/2023] [Accepted: 10/04/2023] [Indexed: 04/17/2024]
Abstract
Reactive halogen species (RHS) are highly reactive compounds that are normally required for regulation of immune response, inflammatory reactions, enzyme function, etc. At the same time, hyperproduction of highly reactive compounds leads to the development of various socially significant diseases - asthma, pulmonary hypertension, oncological and neurodegenerative diseases, retinopathy, and many others. The main sources of (pseudo)hypohalous acids are enzymes from the family of heme peroxidases - myeloperoxidase, lactoperoxidase, eosinophil peroxidase, and thyroid peroxidase. Main targets of these compounds are proteins and peptides, primarily methionine and cysteine residues. Due to the short lifetime, detection of RHS can be difficult. The most common approach is detection of myeloperoxidase, which is thought to reflect the amount of RHS produced, but these methods are indirect, and the results are often contradictory. The most promising approaches seem to be those that provide direct registration of highly reactive compounds themselves or products of their interaction with components of living cells, such as fluorescent dyes. However, even such methods have a number of limitations and can often be applied mainly for in vitro studies with cell culture. Detection of reactive halogen species in living organisms in real time is a particularly acute issue. The present review is devoted to RHS, their characteristics, chemical properties, peculiarities of interaction with components of living cells, and methods of their detection in living systems. Special attention is paid to the genetically encoded tools, which have been introduced recently and allow avoiding a number of difficulties when working with living systems.
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Affiliation(s)
- Yuliya V Khramova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Veronika A Katrukha
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Victoria V Chebanenko
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Alexander I Kostyuk
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, 117997, Russia
| | | | - Oleg M Panasenko
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
| | - Alexey V Sokolov
- Institute of Experimental Medicine, Saint-Petersburg, 197022, Russia.
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
| | - Dmitry S Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, 117997, Russia
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Kettle AJ, Ashby LV, Winterbourn CC, Dickerhof N. Superoxide: The enigmatic chemical chameleon in neutrophil biology. Immunol Rev 2023; 314:181-196. [PMID: 36609987 DOI: 10.1111/imr.13183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The burst of superoxide produced when neutrophils phagocytose bacteria is the defining biochemical feature of these abundant immune cells. But 50 years since this discovery, the vital role superoxide plays in host defense has yet to be defined. Superoxide is neither bactericidal nor is it just a source of hydrogen peroxide. This simple free radical does, however, have remarkable chemical dexterity. Depending on its environment and reaction partners, superoxide can act as an oxidant, a reductant, a nucleophile, or an enzyme substrate. We outline the evidence that inside phagosomes where neutrophils trap, kill, and digest bacteria, superoxide will react preferentially with the enzyme myeloperoxidase, not the bacterium. By acting as a cofactor, superoxide will sustain hypochlorous acid production by myeloperoxidase. As a substrate, superoxide may give rise to other forms of reactive oxygen. We contend that these interactions hold the key to understanding the precise role superoxide plays in neutrophil biology. State-of-the-art techniques in mass spectrometry, oxidant-specific fluorescent probes, and microscopy focused on individual phagosomes are needed to identify bactericidal mechanisms driven by superoxide. This work will undoubtably lead to fascinating discoveries in host defense and give a richer understanding of superoxide's varied biology.
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Affiliation(s)
- Anthony J Kettle
- Department of Pathology & Biomedical Science, Mātai Hāora: Centre for Redox Biology & Medicine, University of Otago Christchurch, Christchurch, New Zealand
| | - Louisa V Ashby
- Department of Pathology & Biomedical Science, Mātai Hāora: Centre for Redox Biology & Medicine, University of Otago Christchurch, Christchurch, New Zealand
| | - Christine C Winterbourn
- Department of Pathology & Biomedical Science, Mātai Hāora: Centre for Redox Biology & Medicine, University of Otago Christchurch, Christchurch, New Zealand
| | - Nina Dickerhof
- Department of Pathology & Biomedical Science, Mātai Hāora: Centre for Redox Biology & Medicine, University of Otago Christchurch, Christchurch, New Zealand
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4
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Parsa SM. Mega-scale desalination Efficacy (Reverse Osmosis, Electrodialysis, Membrane Distillation, MED, MSF) during COVID-19: Evidence from salinity, pretreatment methods, temperature of operation. JOURNAL OF HAZARDOUS MATERIALS ADVANCES 2022:100217. [PMID: 37521749 PMCID: PMC9744688 DOI: 10.1016/j.hazadv.2022.100217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The unprecedented situation of the COVID-19 pandemic heavily polluted water bodies whereas the presence of SARS-CoV-2, even in treated wastewater in every corner of the world is reported. The main aim of the present study is to show the effectiveness and feasibility of some well-known desalination technologies which are reverse osmosis (RO), Electrodialysis (ED), Membrane Distillation (MD), multi effect distillation (MED), and multi stage flashing (MSF) during the COVID-19 pandemic. Systems’ effectiveness against the novel coronavirus based on three parameters of nasopharynx/nasal saline-irrigation, temperature of operation and pretreatment methods are evaluated. First, based on previous clinical studies, it showed that using saline solution (hypertonic saline >0.9% concentration) for gargling/irrigating of nasal/nasopharynx/throat results in reducing and replication of the viral in patients, subsequently the feed water of desalination plants which has concentration higher than 3.5% (35000ppm) is preventive against the SARS-CoV-2 virus. Second, the temperature operation of thermally-driven desalination; MSF and MED (70-120°C) and MD (55-85°C) is high enough to inhibit the contamination of plant structure and viral survival in feed water. The third factor is utilizing various pretreatment process such as chlorination, filtration, thermal/precipitation softening, ultrafiltration (mostly for RO, but also for MD, MED and MSF), which are powerful treatment methods against biologically-contaminated feed water particularly the SARS-CoV-2. Eventually, it can be concluded that large-scale desalination plants during COVID-19 and similar situation are completely reliable for providing safe drinking water.
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Edwards TS, Dickerhof N, Magon NJ, Paton LN, Sly PD, Kettle AJ. Formation of Calprotectin-Derived Peptides in the Airways of Children with Cystic Fibrosis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:979-990. [PMID: 35046105 DOI: 10.4049/jimmunol.2001017] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
Calprotectin is released by activated neutrophils along with myeloperoxidase (MPO) and proteases. It plays numerous roles in inflammation and infection, and is used as an inflammatory biomarker. However, calprotectin is readily oxidized by MPO-derived hypohalous acids to form covalent dimers of its S100A8 and S100A9 subunits. The dimers are susceptible to degradation by proteases. We show that detection of human calprotectin by ELISA declines markedly because of its oxidation by hypochlorous acid and subsequent degradation. Also, proteolysis liberates specific peptides from oxidized calprotectin that is present at inflammatory sites. We identified six calprotectin-derived peptides by mass spectrometry and detected them in the bronchoalveolar lavage fluid of children with cystic fibrosis (CF). We assessed the peptides as biomarkers of neutrophilic inflammation and infection. The content of the calprotectin peptide ILVI was related to calprotectin (r = 0.72, p = 0.01, n = 10). Four of the peptides were correlated with the concentration of MPO (r > 0.7, p ≤ 0.01, n = 21), while three were higher (p < 0.05) in neutrophil elastase-positive (n = 14) than -negative samples (n = 7). Also, five of the peptides were higher (p < 0.05) in the bronchoalveolar lavage fluid from children with CF with infections (n = 21) than from non-CF children without infections (n = 6). The specific peptides liberated from calprotectin will signal uncontrolled activity of proteases and MPO during inflammation. They may prove useful in tracking inflammation in respiratory diseases dominated by neutrophils, including coronavirus disease 2019.
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Affiliation(s)
- Teagan S Edwards
- Department of Paediatrics, University of Otago Christchurch, Christchurch, New Zealand;
| | - Nina Dickerhof
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand; and
| | - Nicholas J Magon
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand; and
| | - Louise N Paton
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand; and
| | - Peter D Sly
- Child Health Research Centre, University of Queensland, Brisbane, Australia
| | - Anthony J Kettle
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand; and
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Ramos DR, Fernández MI, Furtmüller PG, Obinger C, García MV, Santaballa JA, Canle M. Effect of ionizing radiation on human myeloperoxidase: Reaction with hydrated electrons. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 226:112369. [PMID: 34864529 DOI: 10.1016/j.jphotobiol.2021.112369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/31/2021] [Accepted: 11/24/2021] [Indexed: 06/13/2023]
Abstract
Myeloperoxidase (MPO) is a myeloid-lineage restricted enzyme largely expressed in the azurophilic granules of neutrophils. It catalyses the formation of reactive oxygen species, mainly hypochlorous acid, contributing to anti-pathogenic defense. Disorders in the production or regulation of MPO may lead to a variety of health conditions, mainly of inflammatory origin, including autoimmune inflammation. We have studied the effect of ionizing radiation on the activity of MPO, as measured by the capacity retained by the enzyme to produce hypochlorous acid as reactive oxygen species after exposure to successive doses of solvated electrons, the strongest possible one-e- reducing agent in water. Chlorination activity was still present after a very high irradiation dose, indicating that radiation damage does not take place at the active site, hindered in the core of MPO structure. Decay kinetics show a dependence on the wavelength, supporting that the process must occur at peripheral functional groups situated on external and readily accessible locations of the enzyme. These results are relevant to understand the mechanism of resistance of our innate anti-pathogenic defense system and also to get insight into potential strategies to regulate MPO levels as a therapeutic target in autoimmune diseases.
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Affiliation(s)
- Daniel R Ramos
- Universidade da Coruña, Chemical Reactivity & Photoreactivity Group (REACT!), Department of Chemistry, CICA & Faculty of Sciences, A Zapateira s/n, E-15071 A Coruña, Spain.
| | - M Isabel Fernández
- Universidade da Coruña, Chemical Reactivity & Photoreactivity Group (REACT!), Department of Chemistry, CICA & Faculty of Sciences, A Zapateira s/n, E-15071 A Coruña, Spain
| | - Paul G Furtmüller
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - M Victoria García
- Universidade da Coruña, Chemical Reactivity & Photoreactivity Group (REACT!), Department of Chemistry, CICA & Faculty of Sciences, A Zapateira s/n, E-15071 A Coruña, Spain
| | - J Arturo Santaballa
- Universidade da Coruña, Chemical Reactivity & Photoreactivity Group (REACT!), Department of Chemistry, CICA & Faculty of Sciences, A Zapateira s/n, E-15071 A Coruña, Spain
| | - Moisés Canle
- Universidade da Coruña, Chemical Reactivity & Photoreactivity Group (REACT!), Department of Chemistry, CICA & Faculty of Sciences, A Zapateira s/n, E-15071 A Coruña, Spain.
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7
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Nilsson R, Liu NA. Nuclear DNA damages generated by reactive oxygen molecules (ROS) under oxidative stress and their relevance to human cancers, including ionizing radiation-induced neoplasia part I: Physical, chemical and molecular biology aspects. RADIATION MEDICINE AND PROTECTION 2020. [DOI: 10.1016/j.radmp.2020.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Hoskin TS, Crowther JM, Cheung J, Epton MJ, Sly PD, Elder PA, Dobson RCJ, Kettle AJ, Dickerhof N. Oxidative cross-linking of calprotectin occurs in vivo, altering its structure and susceptibility to proteolysis. Redox Biol 2019; 24:101202. [PMID: 31015146 PMCID: PMC6477633 DOI: 10.1016/j.redox.2019.101202] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 01/27/2023] Open
Abstract
Calprotectin, the major neutrophil protein, is a critical alarmin that modulates inflammation and plays a role in host immunity by strongly binding trace metals essential for bacterial growth. It has two cysteine residues favourably positioned to act as a redox switch. Whether their oxidation occurs in vivo and affects the function of calprotectin has received little attention. Here we show that in saliva from healthy adults, and in lavage fluid from the lungs of patients with respiratory diseases, a substantial proportion of calprotectin was cross-linked via disulfide bonds between the cysteine residues on its S100A8 and S100A9 subunits. Stimulated human neutrophils released calprotectin and subsequently cross-linked it by myeloperoxidase-dependent production of hypochlorous acid. The myeloperoxidase-derived oxidants hypochlorous acid, taurine chloramine, hypobromous acid, and hypothiocyanous acid, all at 10 μM, cross-linked calprotectin (5 μM) via reversible disulfide bonds. Hypochlorous acid generated A9-A9 and A8-A9 cross links. Hydrogen peroxide (10 μM) did not cross-link the protein. Purified neutrophil calprotectin existed as a non-covalent heterodimer of A8/A9 which was converted to a heterotetramer - (A8/A9)2 - with excess calcium ions. Low level oxidation of calprotectin with hypochlorous acid produced substantial proportions of high order oligomers, whether oxidation occurred before or after addition of calcium ions. At high levels of oxidation the heterodimer could not form tetramers with calcium ions, but prior addition of calcium ions afforded some protection for the heterotetramer. Oxidation and formation of the A8-A9 disulfide cross link enhanced calprotectin's susceptibility to proteolysis by neutrophil proteases. We propose that reversible disulfide cross-linking of calprotectin occurs during inflammation and affects its structure and function. Its increased susceptibility to proteolysis will ultimately result in a loss of function.
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Affiliation(s)
- Teagan S Hoskin
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand.
| | - Jennifer M Crowther
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Jeanette Cheung
- Canterbury Respiratory Research Group, Respiratory Services, Christchurch Hospital, Canterbury District Health Board, New Zealand
| | - Michael J Epton
- Canterbury Respiratory Research Group, Respiratory Services, Christchurch Hospital, Canterbury District Health Board, New Zealand
| | - Peter D Sly
- Child Health Research Centre, University of Queensland, Brisbane, Australia
| | - Peter A Elder
- Endocrinology and Steroid Laboratory, Canterbury Health Laboratories, New Zealand
| | - Renwick C J Dobson
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand; Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anthony J Kettle
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand
| | - Nina Dickerhof
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand
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9
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Turner R, Brennan SO, Ashby LV, Dickerhof N, Hamzah MR, Pearson JF, Stamp LK, Kettle AJ. Conjugation of urate-derived electrophiles to proteins during normal metabolism and inflammation. J Biol Chem 2018; 293:19886-19898. [PMID: 30385504 DOI: 10.1074/jbc.ra118.005237] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/31/2018] [Indexed: 12/19/2022] Open
Abstract
Urate is often viewed as an antioxidant. Here, we present an alternative perspective by showing that, when oxidized, urate propagates oxidative stress. Oxidation converts urate to the urate radical and the electrophilic products dehydrourate, 5-hydroxyisourate, and urate hydroperoxide, which eventually break down to allantoin. We investigated whether urate-derived electrophiles are intercepted by nucleophilic amino acid residues to form stable adducts on proteins. When urate was oxidized in the presence of various peptides and proteins, two adducts derived from urate (M r 167 Da) were detected and had mass additions of 140 and 166 Da, occurring mainly on lysine residues and N-terminal amines. The adduct with a 140-Da mass addition was detected more frequently and was stable. Dehydrourate (M r 166 Da) also formed transient adducts with cysteine residues. Urate-derived adducts were detected on human serum albumin in plasma of healthy donors. Basal adduct levels increased when neutrophils were added to plasma and stimulated, and relied on the NADPH oxidase, myeloperoxidase, hydrogen peroxide, and superoxide. Adducts of oxidized urate on serum albumin were elevated in plasma and synovial fluid from individuals with gout and rheumatoid arthritis. We propose that rather than acting as an antioxidant, urate's conversion to electrophiles contributes to oxidative stress. The addition of urate-derived electrophiles to nucleophilic amino acid residues, a process we call oxidative uratylation, will leave a footprint on proteins that could alter their function when critical sites are modified.
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Affiliation(s)
- Rufus Turner
- From the Centre for Free Radical Research.,the Department of Pathology and Biomedical Science
| | | | - Louisa V Ashby
- From the Centre for Free Radical Research.,the Department of Pathology and Biomedical Science
| | - Nina Dickerhof
- From the Centre for Free Radical Research.,the Department of Pathology and Biomedical Science
| | - Melanie R Hamzah
- From the Centre for Free Radical Research.,the Department of Pathology and Biomedical Science
| | | | - Lisa K Stamp
- the Department of Medicine, University of Otago Christchurch, P.O. Box 4345, Christchurch 8011, New Zealand
| | - Anthony J Kettle
- From the Centre for Free Radical Research, .,the Department of Pathology and Biomedical Science
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10
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Albrett AM, Ashby LV, Dickerhof N, Kettle AJ, Winterbourn CC. Heterogeneity of hypochlorous acid production in individual neutrophil phagosomes revealed by a rhodamine-based probe. J Biol Chem 2018; 293:15715-15724. [PMID: 30135208 DOI: 10.1074/jbc.ra118.004789] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/12/2018] [Indexed: 01/21/2023] Open
Abstract
The rhodamine-based probe R19-S has been shown to react with hypochlorous acid (HOCl) to yield fluorescent R19, but not with some other oxidants including hydrogen peroxide. Here, we further examined the specificity of R19-S and used it for real-time monitoring of HOCl production in neutrophil phagosomes. We show that it also reacts rapidly with hypobromous acid, bromamines, and hypoiodous acid, indicating that R19-S responds to these reactive halogen species as well as HOCl. Hypothiocyanous acid and taurine chloramine were unreactive, however, and ammonia chloramine and dichloramine reacted only very slowly. MS analyses revealed additional products from the reaction of HOCl with R19-S, including a chlorinated species as a minor product. Of note, phagocytosis of opsonized zymosan or Staphylococcus aureus by neutrophils was accompanied by an increase in R19 fluorescence. This increase depended on NADPH oxidase and myeloperoxidase activities, and detection of chlorinated R19-S confirmed its specificity for HOCl. Using live-cell imaging to track individual phagosomes in single neutrophils, we observed considerable heterogeneity among the phagosomes in the time from ingestion of a zymosan particle to when fluorescence was first detected, ranging from 1 to >30 min. However, once initiated, the subsequent fluorescence increase was uniform, reaching a similar maximum in ∼10 min. Our results confirm the utility of R19-S for detecting HOCl in real-time and provide definitive evidence that isolated neutrophils produce HOCl in phagosomes. The intriguing variability in the onset of HOCl production among phagosomes identified here could influence the way they kill ingested bacteria.
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Affiliation(s)
- Amelia M Albrett
- From the Department of Pathology and Biomedical Science, Centre for Free Radical Research, University of Otago Christchurch, Christchurch 8140, New Zealand
| | - Louisa V Ashby
- From the Department of Pathology and Biomedical Science, Centre for Free Radical Research, University of Otago Christchurch, Christchurch 8140, New Zealand
| | - Nina Dickerhof
- From the Department of Pathology and Biomedical Science, Centre for Free Radical Research, University of Otago Christchurch, Christchurch 8140, New Zealand
| | - Anthony J Kettle
- From the Department of Pathology and Biomedical Science, Centre for Free Radical Research, University of Otago Christchurch, Christchurch 8140, New Zealand
| | - Christine C Winterbourn
- From the Department of Pathology and Biomedical Science, Centre for Free Radical Research, University of Otago Christchurch, Christchurch 8140, New Zealand
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11
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Garai D, Ríos-González BB, Furtmüller PG, Fukuto JM, Xian M, López-Garriga J, Obinger C, Nagy P. Mechanisms of myeloperoxidase catalyzed oxidation of H 2S by H 2O 2 or O 2 to produce potent protein Cys-polysulfide-inducing species. Free Radic Biol Med 2017; 113:551-563. [PMID: 29097214 DOI: 10.1016/j.freeradbiomed.2017.10.384] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/12/2017] [Accepted: 10/26/2017] [Indexed: 01/08/2023]
Abstract
The interaction of heme proteins with hydrogen sulfide is gaining attention as an important element in sulfide-mediated protection against oxidative stress and in regulation of redox signaling. In our previous study we reported the efficient reversible inhibition of myeloperoxidase (MPO) activity by sulfide and the kinetics of the reactions of sulfide with ferric MPO, Compound I and Compound II. Here we provide several lines of evidence that a central intermediate species in the turnover of MPO by sulfide is the Compound III state. Compound III is formed in the reactions of sulfide with ferric or ferrous MPO in the presence of oxygen or via the reductions of Compound I or Compound II by sulfide. The regeneration of active ferric MPO from Compound III is slow - representing the rate-limiting step during turnover - but facilitated by ascorbate or superoxide dismutase. These catalytic cycles produce inorganic sulfane sulfur species, which were shown to promote protein Cys persulfidation. Based on compiling experimental data we propose that in contrast to hemoglobin, myoglobin, catalase or lactoperoxidase the formation of a sulfheme derivative in the oxidative interactions of sulfide with MPO is not a major pathway. Using the Met243Val mutant we demonstrated that the sulfonium ion linkage of the Met243 sulfur to the heme pyrrole ring A, which is a unique feature of MPO, is pivotal in the catalytic oxidation of sulfide via Compound III. The proposed novel MPO-catalyzed sulfide oxidation model does not require the initial presence of hydrogen peroxide, only oxygen to provide a slow flux of sulfane sulfur species generation, which could be important in sulfide-mediated endogenous signaling. Furthermore, peroxide-induced formation of sulfane sulfur species by MPO may have a role in protection of regulatory or functional Cys residues during (for example neutrophil induced) inflammatory oxidative stress.
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Affiliation(s)
- Dorottya Garai
- Department of Molecular Immunology and Toxicology, National Institute of Oncology, Ráth György utca 7-9, Budapest 1122, Hungary
| | - Bessie B Ríos-González
- Department of Chemistry, University of Puerto Rico, Mayagüez Campus, P.O. Box 9019, Mayagüez, PR 00681-9019, United States
| | - Paul G Furtmüller
- Division of Biochemistry, Department of Chemistry, Vienna Institute of BioTechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Jon M Fukuto
- Department of Chemistry, Sonoma State University, Rohnert Park, CA 94928, United States
| | - Ming Xian
- Department of Chemistry, Washington State University, Pullman, WA 99164, United States
| | - Juan López-Garriga
- Department of Chemistry, University of Puerto Rico, Mayagüez Campus, P.O. Box 9019, Mayagüez, PR 00681-9019, United States
| | - Christian Obinger
- Division of Biochemistry, Department of Chemistry, Vienna Institute of BioTechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Péter Nagy
- Department of Molecular Immunology and Toxicology, National Institute of Oncology, Ráth György utca 7-9, Budapest 1122, Hungary.
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12
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Kinkead LC, Allen LAH. Multifaceted effects of Francisella tularensis on human neutrophil function and lifespan. Immunol Rev 2016; 273:266-81. [PMID: 27558340 PMCID: PMC5000853 DOI: 10.1111/imr.12445] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Francisella tularensis in an intracellular bacterial pathogen that causes a potentially lethal disease called tularemia. Studies performed nearly 100 years ago revealed that neutrophil accumulation in infected tissues correlates directly with the extent of necrotic damage during F. tularensis infection. However, the dynamics and details of bacteria-neutrophil interactions have only recently been studied in detail. Herein, we review current understanding regarding the mechanisms that recruit neutrophils to F. tularensis-infected lungs, opsonization and phagocytosis, evasion and inhibition of neutrophil defense mechanisms, as well as the ability of F. tularensis to prolong neutrophil lifespan. In addition, we discuss distinctive features of the bacterium, including its ability to act at a distance to alter overall neutrophil responsiveness to exogenous stimuli, and the evidence which suggests that macrophages and neutrophils play distinct roles in tularemia pathogenesis, such that macrophages are major vehicles for intracellular growth and dissemination, whereas neutrophils drive tissue destruction by dysregulation of the inflammatory response.
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Affiliation(s)
- Lauren C. Kinkead
- Inflammation Program, University of Iowa Iowa City, IA 52242
- Department of Microbiology, University of Iowa Iowa City, IA 52242
| | - Lee-Ann H. Allen
- Inflammation Program, University of Iowa Iowa City, IA 52242
- Department of Microbiology, University of Iowa Iowa City, IA 52242
- Department of Internal Medicine, University of Iowa Iowa City, IA 52242
- VA Medical Center, Iowa City, IA 52242
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13
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Ruggeri RB, Buckbinder L, Bagley SW, Carpino PA, Conn EL, Dowling MS, Fernando DP, Jiao W, Kung DW, Orr STM, Qi Y, Rocke BN, Smith A, Warmus JS, Zhang Y, Bowles D, Widlicka DW, Eng H, Ryder T, Sharma R, Wolford A, Okerberg C, Walters K, Maurer TS, Zhang Y, Bonin PD, Spath SN, Xing G, Hepworth D, Ahn K, Kalgutkar AS. Discovery of 2-(6-(5-Chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamide (PF-06282999): A Highly Selective Mechanism-Based Myeloperoxidase Inhibitor for the Treatment of Cardiovascular Diseases. J Med Chem 2015; 58:8513-28. [DOI: 10.1021/acs.jmedchem.5b00963] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Roger B. Ruggeri
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Leonard Buckbinder
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Scott W. Bagley
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Philip A. Carpino
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Edward L. Conn
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Matthew S. Dowling
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Dilinie P. Fernando
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Wenhua Jiao
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Daniel W. Kung
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Suvi T. M. Orr
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Yingmei Qi
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Benjamin N. Rocke
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Aaron Smith
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Joseph S. Warmus
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Yan Zhang
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Daniel Bowles
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Daniel W. Widlicka
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Heather Eng
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Tim Ryder
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Raman Sharma
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Angela Wolford
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Carlin Okerberg
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Karen Walters
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Tristan S. Maurer
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Yanwei Zhang
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Paul D. Bonin
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Samantha N. Spath
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Gang Xing
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - David Hepworth
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Kay Ahn
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
| | - Amit S. Kalgutkar
- Worldwide Research
and Development, Pfizer,
Inc., Groton, Connecticut 06340, United States
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14
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Abstract
Hydrogen sulfide is now a well-appreciated master regulator in a diverse array of physiological processes. However, as a consequence of the rapid growth of the area, sulfide biology suffers from an increasing number of controversial observations and interpretations. A better understanding of the underlying molecular pathways of sulfide's actions is key to reconcile controversial issues, which calls for rigorous chemical/biochemical investigations. Protein sulfhydration and coordination/redox chemical interactions of sulfide with heme proteins are the two most extensively studied pathways in sulfide biochemistry. These pathways are important mediators of protein functions, generate bioactive sulfide metabolites, contribute to sulfide storage/trafficking and carry antioxidant functions. In addition, inorganic polysulfides, which are oxidative sulfide metabolites, are increasingly recognized as important players in sulfide biology. This chapter provides an overview of our mechanistic perspective on the reactions that govern (i) sulfide's bioavailability (including the delicate enzyme machineries that orchestrate sulfide production and consumption and the roles of the large sulfide-storing pools as biological buffers), (ii) biological significance and mechanisms of persulfide formation (including the reduction of disulfides, condensation with sulfenic acids, oxidation of thiols with polysulfides and radical-mediated pathways), (iii) coordination and redox chemical interactions of sulfide with heme proteins (including cytochrome c oxidase, hemoglobins, myoglobins and peroxidases), and (iv) the chemistry of polysulfides.
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Affiliation(s)
- Péter Nagy
- Department of Molecular Immunology and Toxicology, National Institute of Oncology, Budapest, Hungary.
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15
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Khan AA, Rahmani AH, Aldebasi YH, Aly SM. Biochemical and pathological studies on peroxidases -an updated review. Glob J Health Sci 2014; 6:87-98. [PMID: 25168993 PMCID: PMC4825458 DOI: 10.5539/gjhs.v6n5p87] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 04/17/2014] [Indexed: 12/31/2022] Open
Abstract
Peroxidases represent a family of isoenzymes actively involved in oxidizing reactive oxygen species, innate immunity, hormone biosynthesis and pathogenesis of several diseases. Different types of peroxidases have organ, tissues, cellular and sub-cellular level of specificities in their function. Different diseases lead to varied expressions of peroxidases based on several mechanisms proposed. Several researches are going on to understand its deficiency, over-expression and malfunction in relation with different diseases. Some common diseases of mankind like cancer, cardiovascular diseases and diabetes directly or indirectly involve the role of peroxidases. So the status of peroxidase levels may also function as a marker of different diseases. Although many types of diseases in human beings have a strong correlation with tissue specific peroxidases, the clear role of these oxido-reductases is not yet fully understood. Here we are focusing on the role of peroxidases in relations with different diseases occurring due to oxidative stress.
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Affiliation(s)
- Amjad A Khan
- Dept. of Basic Health Sciences, College of Applied Medical Science, Qassim University, Saudi Arabia.
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16
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Ward J, Spath SN, Pabst B, Carpino PA, Ruggeri RB, Xing G, Speers AE, Cravatt BF, Ahn K. Mechanistic characterization of a 2-thioxanthine myeloperoxidase inhibitor and selectivity assessment utilizing click chemistry--activity-based protein profiling. Biochemistry 2013; 52:9187-201. [PMID: 24320749 DOI: 10.1021/bi401354d] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Myeloperoxidase (MPO) is a heme peroxidase that catalyzes the production of hypochlorous acid. Despite a high level of interest in MPO as a therapeutic target, there have been limited reports about MPO inhibitors that are suitable for evaluating MPO in pharmacological studies. 2-Thioxanthine, 3-(2-ethoxypropyl)-2-thioxo-2,3-dihydro-1H-purin-6(9H)-one (A), has recently been reported to inhibit MPO by covalently modifying the heme prosthetic group. Here we report a detailed mechanistic characterization demonstrating that A possesses all the distinguishing features of a mechanism-based inactivator. A is a time-dependent MPO inhibitor and displays saturable inactivation kinetics consistent with a two-step mechanism of inactivation and a potency (k(inact)/K(I) ratio) of 8450 ± 780 M⁻¹ s⁻¹. MPO inactivation by A is dependent on MPO catalysis and is protected by substrate. A reduces MPO compound I to compound II with a second-order rate constant of (0.801 ± 0.056) × 10⁶ M⁻¹ s⁻¹, and its irreversible inactivation of MPO occurs prior to release of the activated inhibitory species. Despite its relatively high selectivity against a broad panel of more than 100 individual targets, including enzymes, receptors, transporters, and ion channels, we demonstrate that A labels multiple other protein targets in the presence of MPO. By synthesizing an alkyne analogue of A and utilizing click chemistry-activity-based protein profiling, we present that the MPO-activated inhibitory species can diffuse away to covalently modify other proteins, as reflected by the relatively high partition ratio of A, which we determined to be 15.6. This study highlights critical methods that can guide the discovery and development of next-generation MPO inhibitors.
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Affiliation(s)
- Jessica Ward
- Cardiovascular and Metabolic Diseases Research Unit and ‡Medicinal Chemistry, Pfizer Worldwide Research and Development , Cambridge, Massachusetts 02139, United States
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17
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Maitra D, Shaeib F, Abdulhamid I, Abdulridha RM, Saed GM, Diamond MP, Pennathur S, Abu-Soud HM. Myeloperoxidase acts as a source of free iron during steady-state catalysis by a feedback inhibitory pathway. Free Radic Biol Med 2013; 63:90-8. [PMID: 23624305 PMCID: PMC3863623 DOI: 10.1016/j.freeradbiomed.2013.04.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 04/01/2013] [Accepted: 04/08/2013] [Indexed: 02/07/2023]
Abstract
Myeloperoxidase (MPO) is a heme-containing enzyme that generates hypochlorous acid (HOCl) from chloride (Cl(-)) and hydrogen peroxide (H₂O₂). It is implicated in the pathology of several chronic inflammatory conditions such as cardiovascular and pulmonary diseases and cancer. Recently we have shown that HOCl can destroy the heme prosthetic group of hemoproteins. Here, we investigated whether the HOCl formed during steady-state catalysis is able to destroy the MPO heme moiety and thereby function as a major source of free iron. UV-visible spectra and H₂O₂-specific electrode measurements recorded during steady-state HOCl synthesis by MPO showed that the degree of MPO heme destruction increased after multiple additions of H₂O₂ (10 µM), precluding the enzyme from functioning at maximum activity (80-90% inhibition). MPO heme destruction occurred only in the presence of Cl(-). Stopped-flow measurements revealed that the HOCl-mediated MPO heme destruction was complex and occurred through transient ferric species whose formation and decay kinetics indicated it participates in heme destruction along with subsequent free iron release. MPO heme depletion was confirmed by the buildup of free iron utilizing the ferrozine assay. Hypochlorous acid, once generated, first equilibrates in the solution as a whole before binding to the heme iron and initiating heme destruction. Eliminating HOCl from the MPO milieu by scavenging HOCl, destabilizing the MPO-Compound I-Cl complex that could be formed during catalysis, and/or inhibiting MPO catalytic activity partially or completely protects MPO from HOCl insults. Collectively, this study elucidates the bidirectional relationship between MPO and HOCl, which highlights the potential role of MPO as a source of free iron.
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Affiliation(s)
- Dhiman Maitra
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Detroit, MI 48201, USA
| | - Faten Shaeib
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Detroit, MI 48201, USA
| | | | - Rasha M. Abdulridha
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Detroit, MI 48201, USA
| | - Ghassan M. Saed
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Detroit, MI 48201, USA
| | - Michael P. Diamond
- Department of Obstetrics and Gynecology, Georgia Regents University, Augusta, GA 30912, USA
| | - Subramaniam Pennathur
- Division of Nephrology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Husam M. Abu-Soud
- Department of Obstetrics and Gynecology, The C.S. Mott Center for Human Growth and Development, Detroit, MI 48201, USA
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Corresponding author. Fax: 313 577 8554. (H. M. Abu-Soud)
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18
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Winterbourn CC, Kettle AJ. Redox reactions and microbial killing in the neutrophil phagosome. Antioxid Redox Signal 2013; 18:642-60. [PMID: 22881869 DOI: 10.1089/ars.2012.4827] [Citation(s) in RCA: 306] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE When neutrophils kill microorganisms, they ingest them into phagosomes and bombard them with a burst of reactive oxygen species. RECENT ADVANCES This review focuses on what oxidants are produced and how they kill. The neutrophil NADPH oxidase is activated and shuttles electrons from NADPH in the cytoplasm to oxygen in the phagosomal lumen. Superoxide is generated in the narrow space between the ingested organism and the phagosomal membrane and kinetic modeling indicates that it reaches a concentration of around 20 μM. Degranulation leads to a very high protein concentration with up to millimolar myeloperoxidase (MPO). MPO has many substrates, but its main phagosomal reactions should be to dismutate superoxide and, provided adequate chloride, catalyze efficient conversion of hydrogen peroxide to hypochlorous acid (HOCl). Studies with specific probes have shown that HOCl is produced in the phagosome and reacts with ingested bacteria. The amount generated should be high enough to kill. However, much of the HOCl reacts with phagosomal proteins. Generation of chloramines may contribute to killing, but the full consequences of this are not yet clear. CRITICAL ISSUES Isolated neutrophils kill most of the ingested microorganisms rapidly by an MPO-dependent mechanism that is almost certainly due to HOCl. However, individuals with MPO deficiency rarely have problems with infection. A possible explanation is that HOCl provides a frontline response that kills most of the microorganisms, with survivors killed by nonoxidative processes. The latter may deal adequately with low-level infection but with high exposure, more efficient HOCl-dependent killing is required. FUTURE DIRECTIONS Better quantification of HOCl and other oxidants in the phagosome should clarify their roles in antimicrobial action.
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Affiliation(s)
- Christine C Winterbourn
- Centre for Free Radical Research, Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand.
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19
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Klebanoff SJ, Kettle AJ, Rosen H, Winterbourn CC, Nauseef WM. Myeloperoxidase: a front-line defender against phagocytosed microorganisms. J Leukoc Biol 2013; 93:185-98. [PMID: 23066164 PMCID: PMC3545676 DOI: 10.1189/jlb.0712349] [Citation(s) in RCA: 440] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/20/2012] [Accepted: 09/24/2012] [Indexed: 01/01/2023] Open
Abstract
Successful immune defense requires integration of multiple effector systems to match the diverse virulence properties that members of the microbial world might express as they initiate and promote infection. Human neutrophils--the first cellular responders to invading microbes--exert most of their antimicrobial activity in phagosomes, specialized membrane-bound intracellular compartments formed by ingestion of microorganisms. The toxins generated de novo by the phagocyte NADPH oxidase and delivered by fusion of neutrophil granules with nascent phagosomes create conditions that kill and degrade ingested microbes. Antimicrobial activity reflects multiple and complex synergies among the phagosomal contents, and optimal action relies on oxidants generated in the presence of MPO. The absence of life-threatening infectious complications in individuals with MPO deficiency is frequently offered as evidence that the MPO oxidant system is ancillary rather than essential for neutrophil-mediated antimicrobial activity. However, that argument fails to consider observations from humans and KO mice that demonstrate that microbial killing by MPO-deficient cells is less efficient than that of normal neutrophils. We present evidence in support of MPO as a major arm of oxidative killing by neutrophils and propose that the essential contribution of MPO to normal innate host defense is manifest only when exposure to pathogens overwhelms the capacity of other host defense mechanisms.
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Affiliation(s)
| | - Anthony J. Kettle
- Centre for Free Radical Research, Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand; and
| | - Henry Rosen
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Christine C. Winterbourn
- Centre for Free Radical Research, Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand; and
| | - William M. Nauseef
- Iowa Inflammation Program and Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Coralville, Iowa, USA
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20
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Scheeline A, Behrens RL. Potential of levitated drops to serve as microreactors for biophysical measurements. Biophys Chem 2012; 165-166:1-12. [DOI: 10.1016/j.bpc.2012.03.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 03/18/2012] [Accepted: 03/18/2012] [Indexed: 01/15/2023]
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