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JACC. Heart Failure Jul 2023
Topics: Humans; Heart Failure; Peroxidase; Stroke Volume; Ventricular Function, Left; Inflammation
PubMed: 37178083
DOI: 10.1016/j.jchf.2023.04.009 -
Free Radical Biology & Medicine Sep 2023Myeloperoxidase (MPO) is released by neutrophils in inflamed tissues. MPO oxidizes chloride, bromide, and thiocyanate to produce hypochlorous acid (HOCl), hypobromous...
Myeloperoxidase (MPO) is released by neutrophils in inflamed tissues. MPO oxidizes chloride, bromide, and thiocyanate to produce hypochlorous acid (HOCl), hypobromous acid (HOBr), and hypothiocyanous acid (HOSCN), respectively. These oxidants are toxic to pathogens, but may also react with host cells to elicit biological activity and potential toxicity. In cystic fibrosis (CF) and related diseases, increased neutrophil inflammation leads to increased airway MPO and airway epithelial cell (AEC) exposure to its oxidants. In this study, we investigated how equal dose-rate exposures of MPO-derived oxidants differentially impact the metabolome of human AECs (BEAS-2B cells). We utilized enzymatic oxidant production with rate-limiting glucose oxidase (GOX) coupled to MPO, and chloride, bromide (Br), or thiocyanate (SCN) as substrates. AECs exposed to GOX/MPO/SCN (favoring HOSCN) were viable after 24 h, while exposure to GOX/MPO (favoring HOCl) or GOX/MPO/Br (favoring HOBr) developed cytotoxicity after 6 h. Cell glutathione and peroxiredoxin-3 oxidation were insufficient to explain these differences. However, untargeted metabolomics revealed GOX/MPO and GOX/MPO/Br diverged significantly from GOX/MPO/SCN for dozens of metabolites. We noted methionine sulfoxide and dehydromethionine were significantly increased in GOX/MPO- or GOX/MPO/Br-treated cells, and analyzed them as potential biomarkers of lung damage in bronchoalveolar lavage fluid from 5-year-olds with CF (n = 27). Both metabolites were associated with increasing bronchiectasis, neutrophils, and MPO activity. This suggests MPO production of HOCl and/or HOBr may contribute to inflammatory lung damage in early CF. In summary, our in vitro model enabled unbiased identification of exposure-specific metabolite products which may serve as biomarkers of lung damage in vivo. Continued research with this exposure model may yield additional oxidant-specific biomarkers and reveal explicit mechanisms of oxidant byproduct formation and cellular redox signaling.
Topics: Humans; Child, Preschool; Thiocyanates; Peroxidase; Cystic Fibrosis; Bromides; Chlorides; Oxidants; Antioxidants; Hypochlorous Acid; Epithelial Cells; Metabolomics
PubMed: 37356776
DOI: 10.1016/j.freeradbiomed.2023.06.021 -
Journal of Visualized Experiments : JoVE Jan 2024Leukocytospermia can lead to decreased spermatozoa motility, increased spermatozoa morphological abnormalities, elevated spermatozoa DNA fragmentation index, impairment...
Leukocytospermia can lead to decreased spermatozoa motility, increased spermatozoa morphological abnormalities, elevated spermatozoa DNA fragmentation index, impairment of the spermatozoa acrosome function, and even affected embryonic development. It is a common andrological disease in clinical practice and one of the important causes of male infertility. When determining whether male reproductive tract inflammation exists, andrologists often choose to examine round cells or seminal plasma elastase in the semen as a clinical diagnostic basis. However, the examination of round cells is easily influenced by sloughed spermatogenic cells and reproductive tract epithelial cells, which do not contribute to reducing the indiscriminate and unnecessary use of antibiotics. At the same time, the detection process of elastase is relatively complicated, time-consuming, and slow in reporting results, which is not beneficial for early diagnosis and treatment of diseases such as male genital tract infections (MGTIs). We have innovatively applied the examination of peroxidase-positive leukocytes in semen assisted by a computer-assisted semen analysis (CASA) system as a diagnostic criterion for leukocytospermia, successfully solving these problems. This examination only requires the addition of the operating fluid consisting of four reagents into the specimen, and the total reaction time at room temperature can be controlled within 20-30 min. With the subsequent smear and microscopic examination, the concentration of peroxidase-positive leukocytes in semen can be obtained within a total of 60 min, which can be used to diagnose whether the inflammation of the male reproductive tract existed.
Topics: Pregnancy; Female; Male; Humans; Semen; Peroxidase; Spermatozoa; Leukocytes; Pancreatic Elastase; Inflammation
PubMed: 38314916
DOI: 10.3791/66211 -
Nucleic Acids Research Feb 2024Many bacteria form biofilms to protect themselves from predators or stressful environmental conditions. In the biofilm, bacteria are embedded in a protective...
Many bacteria form biofilms to protect themselves from predators or stressful environmental conditions. In the biofilm, bacteria are embedded in a protective extracellular matrix composed of polysaccharides, proteins and extracellular DNA (eDNA). eDNA most often is released from lysed bacteria or host mammalian cells, and it is the only matrix component most biofilms appear to have in common. However, little is known about the form DNA takes in the extracellular space, and how different non-canonical DNA structures such as Z-DNA or G-quadruplexes might contribute to its function in the biofilm. The aim of this study was to determine if non-canonical DNA structures form in eDNA-rich staphylococcal biofilms, and if these structures protect the biofilm from degradation by nucleases. We grew Staphylococcus epidermidis biofilms in laboratory media supplemented with hemin and NaCl to stabilize secondary DNA structures and visualized their location by immunolabelling and fluorescence microscopy. We furthermore visualized the macroscopic biofilm structure by optical coherence tomography. We developed assays to quantify degradation of Z-DNA and G-quadruplex DNA oligos by different nucleases, and subsequently investigated how these enzymes affected eDNA in the biofilms. Z-DNA and G-quadruplex DNA were abundant in the biofilm matrix, and were often present in a web-like structures. In vitro, the structures did not form in the absence of NaCl or mechanical shaking during biofilm growth, or in bacterial strains deficient in eDNA or exopolysaccharide production. We thus infer that eDNA and polysaccharides interact, leading to non-canonical DNA structures under mechanical stress when stabilized by salt. We also confirmed that G-quadruplex DNA and Z-DNA was present in biofilms from infected implants in a murine implant-associated osteomyelitis model. Mammalian DNase I lacked activity against Z-DNA and G-quadruplex DNA, while Micrococcal nuclease could degrade G-quadruplex DNA and S1 Aspergillus nuclease could degrade Z-DNA. Micrococcal nuclease, which originates from Staphylococcus aureus, may thus be key for dispersal of biofilm in staphylococci. In addition to its structural role, we show for the first time that the eDNA in biofilms forms a DNAzyme with peroxidase-like activity in the presence of hemin. While peroxidases are part of host defenses against pathogens, we now show that biofilms can possess intrinsic peroxidase activity in the extracellular matrix.
Topics: Animals; Mice; DNA, Z-Form; DNA, Catalytic; Deoxyribonuclease I; G-Quadruplexes; Micrococcal Nuclease; Sodium Chloride; Hemin; DNA, Bacterial; Biofilms; Staphylococcus; DNA; Polysaccharides; Peroxidase; Mammals
PubMed: 38296834
DOI: 10.1093/nar/gkae034 -
Chemistry & Biodiversity Aug 2023This work describes a unique and environmentally friendly approach for creating three-dimensional (3D) organic-inorganic flower shaped hybrid nanostructures called...
This work describes a unique and environmentally friendly approach for creating three-dimensional (3D) organic-inorganic flower shaped hybrid nanostructures called "nanoflower (NF)" by using Umbilicaria decussate (U. decussate) extract and copper ions (Cu ). U. decussate species were collected from certain place in Antarctic and Turkey and extraction of each species were completed in methanol and water. The U. decussate extracts were used as organic components and Cu acted as inorganic components for formation of U. decussate extracts based hybrid NFs. We rationally used these NFs as novel nanobiocatalyst and antimicrobial agents. These NFs exhibited peroxidase mimic, dye degradation and antimicrobial properties. The NFs were characterized with various techniques. For instance, the morphologies of the NFs were monitored by scanning electron microscope (SEM), presence of elements in the NFs were presented using Energy Dispersive X-Ray Analysis (EDX). Fourier-transform infrared spectroscopy (FT-IR) was used to elucidate corresponding bending and stretching of bonds in the NFs. The NFs acted as effective Fenton agents in the presence of hydrogen peroxide, and we demonstrated their peroxidase-like activity against guaiacol, dye degradation property towards malachite green and antimicrobial activity for Aeromonas hydrophila, Aeromonas sobria, Escherichia coli, Salmonella enterica and Staphylococcus aureus.
Topics: Peroxidase; Spectroscopy, Fourier Transform Infrared; Copper; Antarctic Regions; Turkey; Anti-Infective Agents; Plant Extracts
PubMed: 37172105
DOI: 10.1002/cbdv.202300090 -
Analytical Chemistry Jul 2023Nanozymes are functional nanomaterials with enzyme-like activities, which have good stability and specific nanoscale properties. Among them, peroxidase-like (POD-like)...
Nanozymes are functional nanomaterials with enzyme-like activities, which have good stability and specific nanoscale properties. Among them, peroxidase-like (POD-like) nanozymes with two substrates are the biggest chunk and have been widely applied in biomedical and environmental fields. Maximum velocity () is an essential kinetic parameter, accurate measurements of which can help in activity comparisons, mechanism studies, and nanozyme improvements. At present, the standardized assay determines the catalytic kinetics of POD-like nanozymes by a single fitting based on the Michaelis-Menten equation. However, the true cannot be confirmed by this method due to the test condition that the concentration of a fixed substrate is finite. Here, a double fitting method to determine the intrinsic of POD-like nanozymes is presented, which breaks through the limited concentration of the fixed substrate by an additional Michaelis-Menten fitting. Furthermore, a comparison of the among five typical POD-like nanozymes validates the accuracy and feasibility of our method. This work provides a credible method to determine the true of POD-like nanozymes, helping in activity comparisons and facilitating studies on the mechanism and development of POD-like nanozymes.
Topics: Peroxidase; Peroxidases; Nanostructures; Catalysis; Kinetics; Coloring Agents
PubMed: 37341651
DOI: 10.1021/acs.analchem.3c01830 -
Metabolic Brain Disease Dec 2023Stroke is a leading cause of disability and death worldwide. Ivermectin is a broad-spectrum anti-parasitic agent with potential anti-bacterial, anti-viral, and...
Stroke is a leading cause of disability and death worldwide. Ivermectin is a broad-spectrum anti-parasitic agent with potential anti-bacterial, anti-viral, and anti-cancer effects. However, the effects of ivermectin on the brain are poorly described. This study examined the effects of ivermectin on cerebral ischemia-reperfusion (IR) in rats. A rat model of transient global IR was induced by bilateral carotid artery occlusion for 20 min. Rats received ivermectin (2 mg/kg/day, ip) one hour after inducing cerebral IR for three consecutive days at 24-h intervals. Next, we examined the effects of ivermectin on brain infarction, histopathology, malondialdehyde levels, myeloperoxidase activity, spatial learning and memory, and phospho-AMPK protein levels. The results showed that ivermectin reduced brain infarct size (P < 0.001) and histopathological changes such as cerebral leukocyte accumulation and edema (P < 0.05) compared to untreated rats with IR. Treatment with ivermectin also decreased myeloperoxidase activity (P < 0.01) and malondialdehyde levels (P < 0.05) while increasing AMPK activity (P < 0.001), memory, and learning compared to the untreated IR group. Overall, we show for the first time that ivermectin conferred neuroprotective effects in a rat model of cerebral IR. Our results indicate that three days of treatment with ivermectin reduced brain infarct size, lipid peroxidation, and myeloperoxidase activity and improved memory and learning in rats with cerebral IR. These effects likely occurred via AMPK-dependent mechanisms.
Topics: Rats; Animals; Ischemic Attack, Transient; Neuroprotective Agents; Peroxidase; Ivermectin; AMP-Activated Protein Kinases; Rats, Wistar; Oxidative Stress; Reperfusion Injury; Brain Ischemia; Cerebral Infarction; Antioxidants; Reperfusion; Malondialdehyde
PubMed: 37755672
DOI: 10.1007/s11011-023-01290-8 -
Redox Biology Aug 2023As plants are sessile organisms, they are inevitably exposed to a variety of environmental stimuli that trigger rapid changes in the generation and disposal of reactive... (Review)
Review
As plants are sessile organisms, they are inevitably exposed to a variety of environmental stimuli that trigger rapid changes in the generation and disposal of reactive oxygen species such as hydrogen peroxide (HO). A major HO scavenging system in plant cells is the ascorbate-glutathione cycle, in which ascorbate peroxidase (APX) catalyzes the conversion of HO into water employing ascorbate as specific electron donor. In higher plants, distinct APX isoforms can occur in multiple subcellular compartments, including chloroplasts, mitochondria, and peroxisomes and the cytosol, to modulate organellar and cellular levels of HO. It is well established that APX plays crucial roles in protecting plant cells against diverse environmental stresses, as well as in plant growth and development. Apart from ascorbate, recently, APXs have been found to have a broader substrate specificity and possess chaperone activity, hence participating various biological processes. In this review, we describe the antioxidant properties of APXs and highlight their novel roles beyond 'ascorbate peroxidases'.
Topics: Antioxidants; Ascorbate Peroxidases; Hydrogen Peroxide; Plants; Ascorbic Acid; Peroxidases
PubMed: 37352686
DOI: 10.1016/j.redox.2023.102789 -
American Journal of Respiratory Cell... Feb 2024Oxidative stress, inflammation, and endoplasmic reticulum (ER) stress sequentially occur in bronchopulmonary dysplasia (BPD), and all result in DNA damage. When DNA...
Oxidative stress, inflammation, and endoplasmic reticulum (ER) stress sequentially occur in bronchopulmonary dysplasia (BPD), and all result in DNA damage. When DNA damage becomes irreparable, tumor suppressors increase, followed by apoptosis or senescence. Although cellular senescence contributes to wound healing, its persistence inhibits growth. Therefore, we hypothesized that cellular senescence contributes to BPD progression. Human autopsy lungs were obtained. Sprague-Dawley rat pups exposed to 95% oxygen between Postnatal Day 1 (P1) and P10 were used as the BPD phenotype. -acetyl-lysyltyrosylcysteine-amide (KYC), tauroursodeoxycholic acid (TUDCA), and Foxo4 dri were administered intraperitoneally to mitigate myeloperoxidase oxidant generation, ER stress, and cellular senescence, respectively. Lungs were examined by histology, transcriptomics, and immunoblotting. Cellular senescence increased in rat and human BPD lungs, as evidenced by increased oxidative DNA damage, tumor suppressors, GL-13 stain, and inflammatory cytokines with decreased cell proliferation and lamin B expression. Cellular senescence-related transcripts in BPD rat lungs were enriched at P10 and P21. Single-cell RNA sequencing showed increased cellular senescence in several cell types, including type 2 alveolar cells. In addition, Foxo4-p53 binding increased in BPD rat lungs. Daily TUDCA or KYC, administered intraperitoneally, effectively decreased cellular senescence, improved alveolar complexity, and partially maintained the numbers of type 2 alveolar cells. Foxo4 dri administered at P4, P6, P8, and P10 led to outcomes similar to TUDCA and KYC. Our data suggest that cellular senescence plays an essential role in BPD after initial inducement by hyperoxia. Reducing myeloperoxidase toxic oxidant production, ER stress, and attenuating cellular senescence are potential therapeutic strategies for halting BPD progression.
Topics: Infant, Newborn; Animals; Rats; Humans; Bronchopulmonary Dysplasia; Hyperoxia; Rats, Sprague-Dawley; Lung; Cellular Senescence; Peroxidase; Oxidants; Animals, Newborn; Disease Models, Animal; Taurochenodeoxycholic Acid
PubMed: 37874230
DOI: 10.1165/rcmb.2023-0038OC -
The Journal of Allergy and Clinical... Dec 2023Preschool children with recurrent wheezing are heterogeneous, with differing responses to respiratory viral infections. Although neutrophils are crucial for host...
BACKGROUND
Preschool children with recurrent wheezing are heterogeneous, with differing responses to respiratory viral infections. Although neutrophils are crucial for host defense, their function has not been studied in this population.
OBJECTIVE
We performed functional immunophenotyping on isolated blood neutrophils from 52 preschool children with recurrent wheezing (aeroallergen sensitization, n = 16; no sensitization, n = 36).
METHODS
Blood neutrophils were purified and cultured overnight with polyinosinic:polycytidylic acid [poly(I:C)] as a viral analog stimulus. Neutrophils underwent next-generation sequencing with Reactome pathway analysis and were analyzed for cytokine secretion, apoptosis, myeloperoxidase, and extracellular DNA release. CD14 monocytes were also exposed to neutrophil culture supernatant and analyzed for markers of M1 and M2 activation.
RESULTS
A total of 495 genes, related largely to the innate immune system and neutrophil degranulation, were differently expressed in children with versus without aeroallergen sensitization. Functional experiments identified more neutrophil degranulation and extracellular trap formation (ie, more myeloperoxidase and extracellular DNA) and less neutrophil proinflammatory cytokine secretion in children with aeroallergen sensitization. Neutrophils also shifted CD14 monocytes to a more anti-inflammatory (ie, M2) phenotype in sensitized children and a more proinflammatory (ie, M1) phenotype in nonsensitized children. Although both groups experienced viral exacerbations, annualized exacerbation rates prompting unscheduled health care were also higher in children without aeroallergen sensitization after enrollment.
CONCLUSIONS
Systemic neutrophil responses to viral infection differ by allergic phenotype and may be less effective in preschool children without allergic inflammation. Further studies of neutrophil function are needed in this population, which often has less favorable therapeutic responses to inhaled corticosteroids and other therapies directed at type 2-high inflammation.
Topics: Humans; Child, Preschool; Neutrophils; Respiratory Sounds; Immunophenotyping; Allergens; Inflammation; Cytokines; DNA; Peroxidase
PubMed: 37604313
DOI: 10.1016/j.jaci.2023.08.010