Increased Lung Catalase Activity Confers Protection Against Experimental RSV Infection

The effect of hypochlorous acid inhalation on the activity of antioxidant system enzymes in rats of different ages

Hypochlorous acid HOCl is an effective disinfectant with a broad spectrum and high rate of microbicidal action. Its use for air treatment can be an effective tool for the prevention and therapy of infectious diseases. In this work, the in vivo study was conducted on 110 Wistar Han rats (12 and 72 weeks old) on the effect of a single inhalation of air containing gaseous HOCl on the activity of antioxidant system enzymes. For this, a special installation was designed to uniformly maintain the concentration of HOCl in the air and regulate it over a wide range. Inhalation exposure was carried out for 4 h at total chlorine concentrations in the air of approximately 2.0 mg/m3 and 5.0 mg/m3, after which the animals were observed for 14 days. The effect of inhalation on the antioxidant system activity varied significantly in animals of different ages. Catalase activity in young rats increased approximately 2-fold on days 1-2 after inhalation, regardless of the HOCl concentration, while in old animals a sharp dose-dependent decrease was initially observed. The glutathione peroxidase activity in animals of both ages increased upon inhalation of air with 5.0 mg/m3 HOCl, and in old animals this was more pronounced; when the HOCl concentration decreased to 2.0 mg/m3, this indicator increased slightly in old rats and remained virtually unchanged in young ones. The glutathione reductase activity when exposed to 2.0 mg/m3 HOCl did not change for both age groups, and with increasing HOCl concentration it increased by 1.5-2.0 times in all animals.

Genetic Variations in the Antioxidant Genes and their Role in Modulating Susceptibility Towards Chronic Obstructive Pulmonary Disease in the North Indian population

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a persistent inflammatory lung condition characterized by an obstruction in removing oxygen from the lungs. Oxidant and antioxidant imbalance have long been hallmarks of COPD development, where the amount of antioxidants produced is less than that of oxidants. Here, polymorphism in the antioxidant enzymes like Catalase, Superoxide dismutase and Glutathione peroxidase plays an essential role in regulating the levels of oxidants.

METHODS

1000 subjects, including 500 COPD cases and 500 controls, have been recruited and genotyped to assess the correlation between COPD and the particular SNPS of antioxidant genes. Logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs) to assess the association between SNPs and COPD risk. The relationship between spirometry value and COPD for all SNPs has been analysed using Kruskal Wallis's. Haplotype analysis has also been performed. The effect of SNP interactions on COPD risk was assessed through the Multifactor Dimensionality Reduction (MDR) approach, a nonparametric test for overcoming some of the limitations of the logistic regression for detecting and characterizing SNP interactions.

RESULTS

Our findings indicated a strong association between COPD and the variations in the CAT rs7943316 (OR=0.61, Pc=0.0001), SOD2 rs4880 (OR=2.07, Pc=0.0006), and GPx rs1050450 (OR=0.60, Pc=0.0018). Furthermore, SOD2 rs4880 was associated with forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) of COPD patients. Our study found that the triple combination of SOD1 (rs2234694), SOD1 (rs36232792) and SOD2 (rs4880) was found to be elevating the risk of COPD (OR=2.83, Pc=0.006). SOD2 rs4880 and GPx rs1050450 are also linked to cough and mucus production. The Haplotype study reveals a substantial relationship between CAT (rs7943316 and rs1001179) and SOD (rs2234694 and rs4880), which increases the risk of COPD. The three-locus model (CAT rs794331, CAT rs1101179, and GPx rs1050450) was the most effective for COPD risk assessment based on the MDR findings, which were statistically significant (p<0.0001).

CONCLUSION

This study shows that rs7943316, rs4880, and rs1050450 are associated with the risk of COPD in the north Indian population and have the potential to enhance our knowledge of COPD at the molecular level, which in turn might pave the way for earlier detection, treatment, and preventive efforts.

Exploring Therapeutic Potential of Catalase: Strategies in Disease Prevention and Management

The antioxidant defense mechanisms play a critical role in mitigating the deleterious effects of reactive oxygen species (ROS). Catalase stands out as a paramount enzymatic antioxidant. It efficiently catalyzes the decomposition of hydrogen peroxide (H2O2) into water and oxygen, a potentially harmful byproduct of cellular metabolism. This reaction detoxifies H2O2 and prevents oxidative damage. Catalase has been extensively studied as a therapeutic antioxidant. Its applications range from direct supplementation in conditions characterized by oxidative stress to gene therapy approaches to enhance endogenous catalase activity. The enzyme's stability, bioavailability, and the specificity of its delivery to target tissues are significant hurdles. Furthermore, studies employing conventional catalase formulations often face issues related to enzyme purity, activity, and longevity in the biological milieu. Addressing these challenges necessitates rigorous scientific inquiry and well-designed clinical trials. Such trials must be underpinned by sound experimental designs, incorporating advanced catalase formulations or novel delivery systems that can overcome existing limitations. Enhancing catalase's stability, specificity, and longevity in vivo could unlock its full therapeutic potential. It is necessary to understand the role of catalase in disease-specific contexts, paving the way for precision antioxidant therapy that could significantly impact the treatment of diseases associated with oxidative stress.

Lactoferrin/pectin nanocomplex encapsulating ciprofloxacin and naringin as a lung targeting antibacterial nanoplatform with oxidative stress alleviating effect

Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium with adaptive metabolic abilities. It can cause hospital-acquired infections with significant mortality rates, particularly in people with already existing medical conditions. Its ability to develop resistance to common antibiotics makes managing this type of infections very challenging. Furthermore, oxidative stress is a common consequence of bacterial infection and antibiotic therapy, due to formation of reactive oxygen species (ROS) during their mode of action. In this study we aimed to alleviate oxidative stress and enhance the antibacterial efficacy of ciprofloxacin (CPR) antibiotic by its co-encapsulation with naringin (NAR) within a polyelectrolyte complex (PEX). The PEX comprised of polycationic lactoferrin (LF) and polyanionic pectin (PEC). CPR/NAR-loaded PEX exhibited spherical shape with particle size of 237 ± 3.5 nm, negatively charged zeta potential (-23 ± 2.2 mV) and EE% of 61.2 ± 4.9 for CPR and 76.2 ± 3.4 % for NAR. The LF/PEC complex showed prolonged sequential release profile of CPR to limit bacterial expansion, followed by slow liberation of NAR, which mitigates excess ROS produced by CPR's mechanism of action without affecting its efficacy. Interestingly, this PEX demonstrated good hemocompatibility with no significant in vivo toxicity regarding hepatic and renal functions. In addition, infected mice administrated this nanoplatform intravenously exhibited significant CFU reduction in the lungs and kidneys, along with reduced immunoreactivity against myeloperoxidase. Moreover, this PEX was found to reduce the lungs´ oxidative stress via increasing both glutathione (GSH) and catalase (CAT) levels while lowering malondialdehyde (MDA). In conclusion, CPR/NAR-loaded PEX can offer a promising targeted lung delivery strategy while enhancing the therapeutic outcomes of CPR with reduced oxidative stress.

Modeling Human Respiratory Syncytial Virus (RSV) Infection: Recent Contributions and Future Directions Using the Calf Model of Bovine RSV Disease

The human orthopneumovirus (human respiratory syncytial virus [RSV]) is a leading cause of respiratory disease in children worldwide and a significant cause of infant mortality in low- and middle-income countries. The natural immune response to the virus has a preponderant role in disease progression, with a rapid neutrophil infiltration and dysbalanced T cell response in the lungs associated with severe disease in infants. The development of preventive interventions against human RSV has been difficult partly due to the need to use animal models that only partially recapitulate the immune response as well as the disease progression seen in human infants. In this brief review, we discuss the contributions of the calf model of RSV infection to understanding immunity to RSV and in developing vaccine and drug candidates, focusing on recent research areas. We propose that the bovine model of RSV infection is a valuable alternative for assessing the translational potential of interventions aimed at the human population.

Mitochondria of lung venular capillaries mediate lung-liver cross talk in pneumonia

Failure of the lung's endothelial barrier underlies lung injury, which causes the high mortality acute respiratory distress syndrome (ARDS). Multiple organ failure predisposes to the mortality, but mechanisms are poorly understood. Here, we show that mitochondrial uncoupling protein 2 (UCP2), a component of the mitochondrial inner membrane, plays a role in the barrier failure. Subsequent lung-liver cross talk mediated by neutrophil activation causes liver congestion. We intranasally instilled lipopolysaccharide (LPS). Then, we viewed the lung endothelium by real-time confocal imaging of the isolated, blood-perfused mouse lung. LPS caused alveolar-capillary transfer of reactive oxygen species and mitochondrial depolarization in lung venular capillaries. The mitochondrial depolarization was inhibited by transfection of alveolar Catalase and vascular knockdown of UCP2. LPS instillation caused lung injury as indicated by increases in bronchoalveolar lavage (BAL) protein content and extravascular lung water. LPS or Pseudomonas aeruginosa instillation also caused liver congestion, quantified by liver hemoglobin and plasma aspartate aminotransferase (AST) increases. Genetic inhibition of vascular UCP2 prevented both lung injury and liver congestion. Antibody-mediated neutrophil depletion blocked the liver responses, but not lung injury. Knockdown of lung vascular UCP2 mitigated P. aeruginosa-induced mortality. Together, these data suggest a mechanism in which bacterial pneumonia induces oxidative signaling to lung venular capillaries, known sites of inflammatory signaling in the lung microvasculature, depolarizing venular mitochondria. Successive activation of neutrophils induces liver congestion. We conclude that oxidant-induced UCP2 expression in lung venular capillaries causes a mechanistic sequence leading to liver congestion and mortality. Lung vascular UCP2 may present a therapeutic target in ARDS.NEW & NOTEWORTHY We report that mitochondrial injury in lung venular capillaries underlies barrier failure in pneumonia, and venular capillary uncoupling protein 2 (UCP2) causes neutrophil-mediated liver congestion. Using in situ imaging, we found that epithelial-endothelial transfer of H2O2 activates UCP2, depolarizing mitochondria in venular capillaries. The conceptual advance from our findings is that mitochondrial depolarization in lung capillaries mediates liver cross talk through circulating neutrophils. Pharmacologic blockade of UCP2 could be a therapeutic strategy for lung injury.

Epigenetic control of type III interferon expression by 8-oxoguanine and its reader 8-oxoguanine DNA glycosylase1

Interferons (IFNs) are secreted cytokines with the ability to activate expression of IFN stimulated genes that increase resistance of cells to virus infections. Activated transcription factors in conjunction with chromatin remodelers induce epigenetic changes that reprogram IFN responses. Unexpectedly, 8-oxoguanine DNA glycosylase1 (Ogg1) knockout mice show enhanced stimuli-driven IFN expression that confers increased resistance to viral and bacterial infections and allergen challenges. Here, we tested the hypothesis that the DNA repair protein OGG1 recognizes 8-oxoguanine (8-oxoGua) in promoters modulating IFN expression. We found that functional inhibition, genetic ablation, and inactivation by post-translational modification of OGG1 significantly augment IFN-λ expression in epithelial cells infected by human respiratory syncytial virus (RSV). Mechanistically, OGG1 bound to 8-oxoGua in proximity to interferon response elements, which inhibits the IRF3/IRF7 and NF-κB/RelA DNA occupancy, while promoting the suppressor NF-κB1/p50-p50 homodimer binding to the IFN-λ2/3 promoter. In a mouse model of bronchiolitis induced by RSV infection, functional ablation of OGG1 by a small molecule inhibitor (TH5487) enhances IFN-λ production, decreases immunopathology, neutrophilia, and confers antiviral protection. These findings suggest that the ROS-generated epigenetic mark 8-oxoGua via its reader OGG1 serves as a homeostatic thresholding factor in IFN-λ expression. Pharmaceutical targeting of OGG1 activity may have clinical utility in modulating antiviral response.

SARS-CoV-2 Inhibits NRF2-Mediated Antioxidant Responses in Airway Epithelial Cells and in the Lung of a Murine Model of Infection

Several viruses have been shown to modulate the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), the master regulator of redox homeostasis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the COVID-19 pandemic, also seems to disrupt the balance between oxidants and antioxidants, which likely contributes to lung damage. Using in vitro and in vivo models of infection, we investigated how SARS-CoV-2 modulates the transcription factor NRF2 and its dependent genes, as well as the role of NRF2 during SARS-CoV-2 infection. We found that SARS-CoV-2 infection downregulates NRF2 protein levels and NRF2-dependent gene expression in human airway epithelial cells and in lungs of BALB/c mice. Reductions in cellular levels of NRF2 seem to be independent of proteasomal degradation and the interferon/promyelocytic leukemia (IFN/PML) pathway. Furthermore, lack of the Nrf2 gene in SARS-CoV-2-infected mice exacerbates clinical disease, increases lung inflammation, and is associated with a trend toward increased lung viral titers, indicating that NRF2 has a protective role during this viral infection. In summary, our results suggest that SARS-CoV-2 infection alters the cellular redox balance by downregulating NRF2 and its dependent genes, which exacerbates lung inflammation and disease, therefore, suggesting that the activation of NRF2 could be explored as therapeutic approach during SARS-CoV-2 infection. IMPORTANCE The antioxidant defense system plays a major function in protecting the organism against oxidative damage caused by free radicals. COVID-19 patients often present with biochemical characteristics of uncontrolled pro-oxidative responses in the respiratory tract. We show herein that SARS-CoV-2 variants, including Omicron, are potent inhibitors of cellular and lung nuclear factor erythroid 2-related factor 2 (NRF2), the master transcription factor that controls the expression of antioxidant and cytoprotective enzymes. Moreover, we show that mice lacking the Nrf2 gene show increased clinical signs of disease and lung pathology when infected with a mouse-adapted strain of SARS-CoV-2. Overall, this study provides a mechanistic explanation for the observed unbalanced pro-oxidative response in SARS-CoV-2 infections and suggests that therapeutic strategies for COVID-19 may consider the use of pharmacologic agents that are known to boost the expression levels of cellular NRF2.

Micro-CT Features of Lung Consolidation, Collagen Deposition and Inflammation in Experimental RSV Infection Are Aggravated in the Absence of Nrf2

Severe respiratory syncytial virus (RSV) infections in early life have been linked to the development of chronic airway disease. RSV triggers the production of reactive oxygen species (ROS), which contributes to inflammation and enhanced clinical disease. NF-E2-related factor 2 (Nrf2) is an important redox-responsive protein that helps to protect cells and whole organisms from oxidative stress and injury. The role of Nrf2 in the context of viral-mediated chronic lung injury is not known. Herein, we show that RSV experimental infection of adult Nrf2-deficient BALB/c mice (Nrf2-/-; Nrf2 KO) is characterized by enhanced disease, increased inflammatory cell recruitment to the bronchoalveolar compartment and a more robust upregulation of innate and inflammatory genes and proteins, compared to wild-type Nrf2+/+ competent mice (WT). These events that occur at very early time points lead to increased peak RSV replication in Nrf2 KO compared to WT mice (day 5). To evaluate longitudinal changes in the lung architecture, mice were scanned weekly via high-resolution micro-computed tomography (micro-CT) imaging up to 28 days after initial viral inoculation. Based on micro-CT qualitative 2D imaging and quantitative reconstructed histogram-based analysis of lung volume and density, we found that RSV-infected Nrf2 KO mice developed significantly greater and prolonged fibrosis compared to WT mice. The results of this study underscore the critical role of Nrf2-mediated protection from oxidative injury, not only in the acute pathogenesis of RSV infection but also in the long-term consequences of chronic airway injury.

Bioactive fraction from Plumeria obtusa L. attenuates LPS-induced acute lung injury in mice and inflammation in RAW 264.7 macrophages: LC/QToF-MS and molecular docking

In this study, the anti-inflammatory effects of the methanolic extract (TE) of Plumeria obtusa L. (aerial parts) and its fractions were evaluated in vitro, and active fraction was evaluated in vivo. Among tested extracts, dichloromethane fraction (DCM-F) exhibited the strongest inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) in RAW 264.7 macrophages. The effect of DCM-F on LPS-induced acute lung injury (ALI) in mice was studied. The animals were divided into five groups (n = 7) randomly; Gp I: negative control, GP II: positive control (LPS group), GP III: standard (dexamethasone, 2 mg/kg b.wt), GP IV and V: DCM-F (100 mg/kg), and DEM-F (200 mg/kg), respectively. DCM-F at a dose of 200 mg/kg suppressed the ability of LPS to increase the levels of nitric oxide synthase (iNOS), NO, tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6), as measured by ELISA. In addition, the expression of cyclooxygenase-2 (COX-2) was reduced (determined by immunohistochemistry) and the level of malondialdehyde (MDA) was decreased while that of catalase was restored to the normal values. Furthermore, the histopathological scores of inflammation induced by LPS were reduced. Twenty-two compounds were tentatively identified in DCM-F using LC/ESI-QToF with iridoids, phenolic derivatives and flavonoids as major constituents. Identified compounds were subjected to two different molecular docking processes against iNOS and prostaglandin E synthase-1 target receptors. Notably, protoplumericin A and 13-O-coumaroyl plumeride were the most promising members compared to the co-crystallized inhibitor in each case. These findings suggested that DCM-F attenuates the LPS-induced ALI in experimental animals through its anti-inflammatory and antioxidant potential.

Biomimetic nanomaterial-facilitated oxygen generation strategies for enhancing tumour treatment outcomes

Hypoxia, as a typical hallmark of the tumour microenvironment (TME), has been verified to exist in most malignancies and greatly hinders the outcome of tumour treatments, including chemotherapy, photodynamic therapy, radiotherapy, and immunotherapy. Various approaches to alleviate tumour hypoxia have been reported. Among them, biomimetic nanomaterial-facilitated tumour oxygenation strategies, based on the engagement of human endogenous proteins, red blood cells, the cell membrane, and catalase, are the most impressive due to their excellent tumour active-targeting ability and superior tumour-selective capability, which, however, have not yet been systematically reviewed. Herein, we are ready to describe the current progress in biomimetic nanomaterial-facilitated tumour oxygenation strategies and corresponding improvements in tumour treatment outputs. In this review, the underlying mechanism behind the superior effect of these biomimetic nanomaterials, compared with other materials, on alleviating the hypoxic TME is highlighted. Additionally, the ongoing problems and potential solutions are also discussed.

Innate Immune Responses to RSV Infection Facilitated by OGG1, an Enzyme Repairing Oxidatively Modified DNA Base Lesions

The primary cause of morbidity and mortality from infection with respiratory syncytial virus (RSV) is the excessive innate immune response(s) (IIR) in which reactive oxygen species (ROS) play key role(s). However, the mechanisms for these processes are not fully understood. We hypothesized that expressions of IIR genes are controlled by the ROS-generated epigenetic-like mark 7,8-dihydro-8-oxo(d)guanine (8-oxo(d)Gua) and 8-oxoguanine DNA glycosylase1 (OGG1). Here, we report that ROS not only generates intrahelical 8-oxo(d)Gua, but also enzymatically disables OGG1 in RSV-infected human airway epithelial cells and mouse lungs. OGG1 bound to 8-oxo(d)Gua in gene regulatory sequences promotes expression of IIR genes, and consequently exacerbates lung inflammation, histological changes, and body weight loss of experimental animals. Pharmacological inhibition of OGG1 substrate binding decreased expression of RSV-induced chemokine and cytokines and significantly lessened clinical symptoms. Results of mechanistic studies show that OGG1 binding at 8-oxo(d)Gua promoter regions modulated loading of transcription factors via transient cooperative interactions in RSV-infected lungs and airway epithelial cells. Other base specific DNA repair proteins had no effects. Collectively, this study identifies unprecedented roles of ROS-generated DNA base lesion(s) and cognate repair protein as a determinant of RSV-induced exuberant inflammation. Pharmaceutical inhibition of OGG1 interaction with its DNA substrate may represent a novel strategy in prevention/intervention of respiratory viral infections.

In vivo study of dose-dependent antioxidant efficacy of functionalized core-shell yttrium oxide nanoparticles

Abstract

Herein, we assess the dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide. The antioxidant properties of these nanoparticles were investigated in three groups of Sprague–Dawley rats (10 per group) exposed to environmental stress daily for 1 week and one control group. Groups 2 and 3 were intravenously injected twice a week with YNPs at 0.3 and 0.5 mg at 2nd and 5th day of environmental stress exposure respectively. Different samples of blood and serum were collected from all experimental groups at end of the experiment to measure oxidative biomarkers such as total antioxidant capacity (TAC), hydroxyl radical antioxidant capacity (HORAC), oxygen radical antioxidant capacity (ORAC), malondialdehyde (MDA), and oxidants concentration as hydrogen peroxide (H₂O₂). The liver, brain, and spleen tissues were collected for fluorescence imaging and histopathological examination in addition to brain tissue examination by transmission electron microscope (TEM). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to estimate YNPs translocation and concentration in tissues which is consecutively dependent on the dose of administration. Depending on all results, poly EGMP YNPs (poly EGMP yttrium oxide nanoparticles) can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB). Also, the neuroprotective effect of YNPs opening the door to a new therapeutic approach for modulating oxidative stress–related neural disorders.

Highlights

• The dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide was assessed.

• The dose of administration directly affecting the brain, liver, and spleen tissues distribution, retention, and uptake of YNPs and direct correlation between the absorbed amount and higher dose administered.

• YNPs can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB).

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00210-022-02219-1.

Effect of Maternal Catalase Supplementation on Reproductive Performance, Antioxidant Activity and Mineral Transport in Sows and Piglets

This experiment was conducted to investigate the effects of maternal catalase (CAT) supplementation on reproductive performance, antioxidant enzyme activities, mineral transport, and mRNA expression of related genes in sows and offspring. A total of 40 pregnant sows at 95 days of gestation with similar parity (3−5 parities) and back-fat thickness were assigned randomly and equally into the control (CON) group (fed a basal diet) and CAT group (fed a basal diet supplemented with 660 mg/kg CAT; CAT activity, 280 U/g). The reproductive performance was recorded, and the placenta and blood samples of sows and neonatal piglets, as well as the jejunum and ileum samples from neonatal boars (eight replicates per group), were collected. Results showed that dietary supplementation with CAT significantly decreased the intrauterine growth restriction (IUGR) rate and increased the activity of serum CAT in neonatal piglets and umbilical cords (p < 0.05). In addition, CAT supplementation tended to improve total antioxidant capacity (T-AOC) levels in the maternal serum (p = 0.089) and umbilical cords of piglets (p = 0.051). The serum calcium (Ca), manganese (Mn), and zinc (Zn) of farrowing sows and Mn concentration in the umbilical cord, and serum Ca, magnesium (Mg), copper (Cu), and Mn of neonatal piglets were significantly increased (p < 0.05) in the CAT group. CAT supplementation downregulated mRNA expression of TRPV6 and CTR1 (p < 0.05), Cu/Zn SOD (p = 0.086) in the placenta and tended to increase the mRNA expression of the glutathione peroxidase 1 (GPX1) (p = 0.084), glutathione peroxidase 4 (GPX4) (p = 0.063), and CAT (p = 0.052) genes in the ileum of piglets. These results showed that the maternal CAT supplementation improved fetal growth by decreasing the IUGR rate, and modulated antioxidant activity, as well as mineral elements in the pregnant sows and their piglets.

Promising Indicators in Probiotic-recommendations in COVID-19 and its Accompanying Diseases

Scientific data suggests the possible beneficial role of probiotics in treatments for COVID-19, but the species/strains-specificity and disease-specificity of probiotics need high attention in choosing the appropriate probiotic in diseases, in particularly in the COVID-19. We hope this review will raise awareness of the COVID-19 probiotic recommendations, highlighting the latest scientific information about virus/hydrogen peroxide/probiotics and the importance of finding out of a specific “criterion” for the probiotics’ recommendation in this disease.

CCR5 antagonist treatment inhibits vascular injury by regulating NADPH oxidase 1

BACKGROUND

Chemokine (C- Cmotif) ligand 5 (CCL5) and its receptor C-C motif chemokine receptor 5 (CCR5), have been broadly studied in conjunction with infectious pathogens, however, their involvement in cardiovascular disease is not completely understood. NADPH oxidases (Noxs) are the major source of reactive oxygen species (ROS) in the vasculature. Whether the activation of Noxs is CCL5/CCR5 sensitive and whether such interaction initiates vascular injury is unknown. We investigated whether CCL5/CCR5 leads to vascular damage by activating Noxs.

MATERIAL AND METHODS

We used rat aortic smooth muscle cells (RASMC) to investigate the molecular mechanisms by which CCL5 leads to vascular damage and carotid ligation (CL) to analyze the effects of blocking CCR5 on vascular injury.

RESULTS

CCL5 induced Nox1 expression in concentration and time-dependent manners, with no changes in Nox2 or Nox4. Maraviroc pre-treatment (CCR5 antagonist, 40uM) blunted CCL5-induced Nox1 expression. Furthermore, CCL5 incubation led to ROS production and activation of Erk1/2 and NFkB, followed by increased vascular cell migration, proliferation, and inflammatory markers. Notably, Nox1 inhibition (GKT771, 10uM) blocked CCL5-dependent effects. In vivo, CL induced pathological vascular remodeling and inflammatory genes and increased Nox1 and CCR5 expression. Maraviroc treatment (25 mg/Kg/day) reduced pathological vascular growth and Nox1 expression.

CONCLUSIONS

Our findings suggest that CCL5 activates Nox1 in the vasculature, leading to vascular injury likely via NFkB and Erk1/2. Herein, we place CCR5 antagonists and/or Nox1 inhibitors might be preeminent antiproliferative compounds to reduce the cardiovascular risk associated with medical procedures (e.g. angioplasty) and vascular diseases associated with vascular hyperproliferation.

Endothelial Dysfunction through Oxidatively Generated Epigenetic Mark in Respiratory Viral Infections

The bronchial vascular endothelial network plays important roles in pulmonary pathology during respiratory viral infections, including respiratory syncytial virus (RSV), influenza A(H1N1) and importantly SARS-Cov-2. All of these infections can be severe and even lethal in patients with underlying risk factors.A major obstacle in disease prevention is the lack of appropriate efficacious vaccine(s) due to continuous changes in the encoding capacity of the viral genome, exuberant responsiveness of the host immune system and lack of effective antiviral drugs. Current management of these severe respiratory viral infections is limited to supportive clinical care. The primary cause of morbidity and mortality is respiratory failure, partially due to endothelial pulmonary complications, including edema. The latter is induced by the loss of alveolar epithelium integrity and by pathological changes in the endothelial vascular network that regulates blood flow, blood fluidity, exchange of fluids, electrolytes, various macromolecules and responses to signals triggered by oxygenation, and controls trafficking of leukocyte immune cells. This overview outlines the latest understanding of the implications of pulmonary vascular endothelium involvement in respiratory distress syndrome secondary to viral infections. In addition, the roles of infection-induced cytokines, growth factors, and epigenetic reprogramming in endothelial permeability, as well as emerging treatment options to decrease disease burden, are discussed.

Evolution of proteomics technologies for understanding respiratory syncytial virus pathogenesis

Introduction: Respiratory syncytial virus (RSV) is a major human pathogen associated with long term morbidity. RSV replication occurs primarily in the epithelium, producing a complex cellular response associated with acute inflammation and long-lived changes in pulmonary function and allergic disease. Proteomics approaches provide important insights into post-transcriptional regulatory processes including alterations in cellular complexes regulating the coordinated innate response and epigenome.Areas covered: Peer-reviewed proteomics studies of host responses to RSV infections and proteomics techniques were analyzed. Methodologies identified include 1)." bottom-up" discovery proteomics, 2). Organellar proteomics by LC-gel fractionation; 3). Dynamic changes in protein interaction networks by LC-MS; and 4). selective reaction monitoring MS. We introduce recent developments in single-cell proteomics, top-down mass spectrometry, and photo-cleavable surfactant chemistries that will have impact on understanding how RSV induces extracellular matrix (ECM) composition and airway remodeling.Expert opinion: RSV replication induces global changes in the cellular proteome, dynamic shifts in nuclear proteins, and remodeling of epigenetic regulatory complexes linked to the innate response. Pathways discovered by proteomics technologies have led to deeper mechanistic understanding of the roles of heat shock proteins, redox response, transcriptional elongation complex remodeling and ECM secretion remodeling in host responses to RSV infections and pathological sequelae.

Nanoenabled Tumor Oxygenation Strategies for Overcoming Hypoxia-Associated Immunosuppression

Cancer immunotherapy, which initiates or strengthens innate immune responses to attack cancer cells, has shown great promise in cancer treatment. However, low immune response impacted by immunosuppressive tumor microenvironment (TME) remains a key challenge, which has been found related to tumor hypoxia. Recently, nanomaterial systems are proving to be excellent platforms for tumor oxygenation, which can reverse hypoxia-associated immunosuppression, strengthen the systemic antitumor immune responses, and thus afford a striking abscopal effect to clear metastatic cancer cells. In this review, we would like to survey recent progress in utilizing nanomaterials for tumor oxygenation through approaches such as in situ O₂ generation, O₂ delivery, tumor vasculature normalization, and mitochondrial-respiration inhibition. Their effects on tumor hypoxia-associated immunosuppression are highlighted. We also discuss the ongoing challenges and how to further improve the clinical prospect of cancer immunotherapy.

Selective Blockade of TNFR1 Improves Clinical Disease and Bronchoconstriction in Experimental RSV Infection

Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis in infants and young children. Although some clinical studies have speculated that tumor necrosis factor (TNF)-α is a major contributor of RSV-mediated airway disease, experimental evidence remains unclear or conflicting. TNF-α initiates inflammation and cell death through two distinct receptors: TNF-receptor (TNFR)1 and TNFR2. Here we delineate the function of TNF-α by short-lasting blockade of either receptor in an experimental BALB/c mouse model of RSV infection. We demonstrate that antibody-mediated blockade of TNFR1, but not TNFR2, results in significantly improved clinical disease and bronchoconstriction as well as significant reductions of several inflammatory cytokines and chemokines, including IL-1α, IL-1β, IL-6, Ccl3, Ccl4, and Ccl5. Additionally, TNFR1 blockade was found to significantly reduce neutrophil number and activation status, consistent with the concomitant reduction of pro-neutrophilic chemokines Cxcl1 and Cxcl2. Similar protective activity was also observed when a single-dose of TNFR1 blockade was administered to mice following RSV inoculation, although this treatment resulted in improved alveolar macrophage survival rather than reduced neutrophil activation. Importantly, short-lasting blockade of TNFR1 did not affect RSV peak replication in the lung. This study suggests a potential therapeutic approach for RSV bronchiolitis based on selective blockade of TNFR1.

COVID-19: Proposing a Ketone-Based Metabolic Therapy as a Treatment to Blunt the Cytokine Storm

Human SARS-CoV-2 infection is characterized by a high mortality rate due to some patients developing a large innate immune response associated with a cytokine storm and acute respiratory distress syndrome (ARDS). This is characterized at the molecular level by decreased energy metabolism, altered redox state, oxidative damage, and cell death. Therapies that increase levels of (R)-beta-hydroxybutyrate (R-BHB), such as the ketogenic diet or consuming exogenous ketones, should restore altered energy metabolism and redox state. R-BHB activates anti-inflammatory GPR109A signaling and inhibits the NLRP3 inflammasome and histone deacetylases, while a ketogenic diet has been shown to protect mice from influenza virus infection through a protective γδ T cell response and by increasing electron transport chain gene expression to restore energy metabolism. During a virus-induced cytokine storm, metabolic flexibility is compromised due to increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that damage, downregulate, or inactivate many enzymes of central metabolism including the pyruvate dehydrogenase complex (PDC). This leads to an energy and redox crisis that decreases B and T cell proliferation and results in increased cytokine production and cell death. It is hypothesized that a moderately high-fat diet together with exogenous ketone supplementation at the first signs of respiratory distress will increase mitochondrial metabolism by bypassing the block at PDC. R-BHB-mediated restoration of nucleotide coenzyme ratios and redox state should decrease ROS and RNS to blunt the innate immune response and the associated cytokine storm, allowing the proliferation of cells responsible for adaptive immunity. Limitations of the proposed therapy include the following: it is unknown if human immune and lung cell functions are enhanced by ketosis, the risk of ketoacidosis must be assessed prior to initiating treatment, and permissive dietary fat and carbohydrate levels for exogenous ketones to boost immune function are not yet established. The third limitation could be addressed by studies with influenza-infected mice. A clinical study is warranted where COVID-19 patients consume a permissive diet combined with ketone ester to raise blood ketone levels to 1 to 2 mM with measured outcomes of symptom severity, length of infection, and case fatality rate.

Preliminary Trichinella spiralis Infection Ameliorates Subsequent RSV Infection-Induced Inflammatory Response

Respiratory syncytial virus (RSV) infection affects the lives of neonates throughout the globe, causing a high rate of mortality upon hospital admission. Yet, therapeutic options to deal with this pulmonary pathogen are currently limited. Helminth therapy has been well received for its immunomodulatory role in hosts, which are crucial for mitigating a multitude of diseases. Therefore, in this study, we used the helminth Trichinella spiralis and assessed its capabilities for modulating RSV infection as well as the inflammatory response induced by it in mice. Our results revealed that RSV-specific antibody responses were enhanced by pre-existing T. spiralis infection, which also limited pulmonary viral replication. Diminished lung inflammation, indicated by reduced pro-inflammatory cytokines and inflammatory cell influx was confirmed, as well as through histopathological assessment. We observed that inflammation-associated nuclear factor kappa-light-chain enhancement of activated B cells (NF-κB) and its phosphorylated forms were down-regulated, whereas antioxidant-associated nuclear factor erythroid 2-related factor 2 (Nrf2) protein expression was upregulated in mice co-infected with T. spiralis and RSV. Upregulated Nrf2 expression contributed to increased antioxidant enzyme expression, particularly NQO1 which relieved the host of oxidative stress-induced pulmonary inflammation caused by RSV infection. These findings indicate that T. spiralis can mitigate RSV-induced inflammation by upregulating the expression of antioxidant enzymes.

Early-Life Respiratory Syncytial Virus Infection, Trained Immunity and Subsequent Pulmonary Diseases

Respiratory syncytial virus (RSV) is often the first clinically relevant pathogen encountered in life, with nearly all children infected by two years of age. Many studies have also linked early-life severe respiratory viral infection with more pathogenic immune responses later in life that lead to pulmonary diseases like childhood asthma. This phenomenon is thought to occur through long-term immune system alterations following early-life respiratory viral infection and may include local responses such as unresolved inflammation and/or direct structural or developmental modifications within the lung. Furthermore, systemic responses that could impact the bone marrow progenitors may be a significant cause of long-term alterations, through inflammatory mediators and shifts in metabolic profiles. Among these alterations may be changes in transcriptional and epigenetic programs that drive persistent modifications throughout life, leaving the immune system poised toward pathogenic responses upon secondary insult. This review will focus on early-life severe RSV infection and long-term alterations. Understanding these mechanisms will not only lead to better treatment options to limit initial RSV infection severity but also protect against the development of childhood asthma linked to severe respiratory viral infections.