Redox-Modulating Agents in the Treatment of Viral Infections

Unveiling the intersection: ferroptosis in influenza virus infection

The influenza virus (IFV) imposes a considerable health and economic burden globally, requiring a comprehensive understanding of its pathogenic mechanisms. Ferroptosis, an iron-dependent lipid peroxidation cell death pathway, holds unique implications for the antioxidant defense system, with possible contributions to inflammation. This exploration focuses on the dynamic interplay between ferroptosis and the host defense against viruses, emphasizing the influence of IFV infections on the activation of the ferroptosis pathway. IFV causes different types of cell death, including apoptosis, necrosis, and ferroptosis. IFV-induced ferroptotic cell death is mediated by alterations in iron homeostasis, intensifying the accumulation of reactive oxygen species and promoting lipid peroxidation. A comprehensive investigation into the mechanism of ferroptosis in viral infections, specifically IFV, has great potential to identify therapeutic strategies. This understanding may pave the way for the development of drugs using ferroptosis inhibitors, presenting an effective approach to suppress viral infections.

The Role of the Nrf2 Pathway in Airway Tissue Damage Due to Viral Respiratory Infections

Respiratory viruses constitute a significant cause of illness and death worldwide. Respiratory virus-associated injuries include oxidative stress, ferroptosis, inflammation, pyroptosis, apoptosis, fibrosis, autoimmunity, and vascular injury. Several studies have demonstrated the involvement of the nuclear factor erythroid 2-related factor 2 (Nrf2) in the pathophysiology of viral infection and associated complications. It has thus emerged as a pivotal player in cellular defense mechanisms against such damage. Here, we discuss the impact of Nrf2 activation on airway injuries induced by respiratory viruses, including viruses, coronaviruses, rhinoviruses, and respiratory syncytial viruses. The inhibition or deregulation of Nrf2 pathway activation induces airway tissue damage in the presence of viral respiratory infections. In contrast, Nrf2 pathway activation demonstrates protection against tissue and organ injuries. Clinical trials involving Nrf2 agonists are needed to define the effect of Nrf2 therapeutics on airway tissues and organs damaged by viral respiratory infections.

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.

NRF2-mediated regulation of lipid pathways in viral infection

The first line of defense against viral infection of the host cell is the cellular lipid membrane, which is also a crucial first site of contact for viruses. Lipids may sometimes be used as viral receptors by viruses. For effective infection, viruses significantly depend on lipid rafts during the majority of the viral life cycle. It has been discovered that different viruses employ different lipid raft modification methods for attachment, internalization, membrane fusion, genome replication, assembly, and release. To preserve cellular homeostasis, cells have potent antioxidant, detoxifying, and cytoprotective capabilities. Nuclear factor erythroid 2-related factor 2 (NRF2), widely expressed in many tissues and cell types, is one crucial component controlling electrophilic and oxidative stress (OS). NRF2 has recently been given novel tasks, including controlling inflammation and antiviral interferon (IFN) responses. The activation of NRF2 has two effects: it may both promote and prevent the development of viral diseases. NRF2 may also alter the host's metabolism and innate immunity during viral infection. However, its primary function in viral infections is to regulate reactive oxygen species (ROS). In several research, the impact of NRF2 on lipid metabolism has been examined. NRF2 is also involved in the control of lipids during viral infection. We evaluated NRF2's function in controlling viral and lipid infections in this research. We also looked at how lipids function in viral infections. Finally, we investigated the role of NRF2 in lipid modulation during viral infections.

In Silico Prediction of Functional SNPs Interrupting Antioxidant Defense Genes in Relation to COVID-19 Progression

The excessive production of reactive oxygen species and weakening of antioxidant defense system play a pivotal role in the pathogenesis of different diseases. Extensive differences observed among individuals in terms of affliction with cancer, cardiovascular disorders, diabetes, bacterial, and viral infections, as well as response to treatments can be partly due to their genomic variations. In this work, we attempted to predict the effect of SNPs of the key genes of antioxidant defense system on their structure, function, and expression in relation to COVID-19 pathogenesis using in silico tools. In addition, the effect of SNPs on the target site binding efficiency of SNPs was investigated as a factor with potential to change drug response or susceptibility to COVID-19. According to the predicted results, only six missense SNPs with minor allele frequency (MAF) ≥ 0.1 in the coding region of genes GPX7, GPX8, TXNRD2, GLRX5, and GLRX were able to strongly affect their structure and function. Our results predicted that 39 SNPs with MAF ≥ 0.1 led to the generation or destruction of miRNA-binding sites on target antioxidant genes from GPX, PRDX, GLRX, TXN, and SOD families. The results obtained from comparing the expression profiles of mild vs. severe COVID-19 patients using GEO2R demonstrated a significant change in the expression of approximately 250 miRNAs. The binding efficiency of 21 of these miRNAs was changed due to the elimination or generation of target sites in these genes. Altogether, this study reveals the fundamental role of the SNPs of antioxidant defense genes in COVID-19 progression and susceptibility of individuals to this virus. In addition, different responses of COVID-19 patients to antioxidant defense system enhancement drugs may be due to presence of these SNPs in different individuals.

Plant extracts modulate cellular stress to inhibit replication of mouse Coronavirus MHV-A59

The Covid-19 infection outbreak led to a global epidemic, and although several vaccines have been developed, the appearance of mutations has allowed the virus to evade the immune response. Added to this is the existing risk of the appearance of new emerging viruses. Therefore, it is necessary to explore novel antiviral therapies. Here, we investigate the potential in vitro of plant extracts to modulate cellular stress and inhibit murine hepatitis virus (MHV)-A59 replication. L929 cells were treated with P2Et (Caesalpinia spinosa) and Anamu SC (Petiveria alliacea) plant extracts during infection and virus production, ROS (reactive oxygen species), UPR (unfolded protein response), and autophagy were assessed. P2Et inhibited virus replication and attenuated both ROS production and UPR activation induced during infection. In contrast, the sustained presence of Anamu SC during viral adsorption and replication was required to inhibit viral infection, tending to induce pro-oxidant effects, and increasing UPR gene expression. Notably, the loss of the PERK protein resulted in a slight decrease in virus yield, suggesting a potential involvement of this UPR pathway during replication. Intriguingly, both extracts either maintained or increased the calreticulin surface exposure induced during infection. In conclusion, our findings highlight the development of antiviral natural plant extracts that differentially modulate cellular stress.

Peppermint and menthol: a review on their biochemistry, pharmacological activities, clinical applications, and safety considerations

In this manuscript, we conducted a comprehensive review of the diverse effects of peppermint on human health and explored the potential underlying mechanisms. Peppermint contains three main groups of phytochemical constituents, including essential oils (mainly menthol), flavonoids (such as hesperidin, eriodictyol, naringenin, quercetin, myricetin, and kaempferol), and nonflavonoid phenolcarboxylic acids. Peppermint exhibits antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, anti-cancer, anti-aging, and analgesic properties and may be effective in treating various disorders, including gastrointestinal disorders (e.g., irritable bowel syndrome, dyspepsia, constipation, functional gastrointestinal disorders, nausea/vomiting, and gallbladder stones). In addition, peppermint has therapeutic benefits for psychological and cognitive health, dental health, urinary retention, skin and wound healing, as well as anti-depressant and anti-anxiety effects, and it may improve memory. However, peppermint has paradoxical effects on sleep quality and alertness, as it has been shown to improve sleep quality in patients with fatigue and anxiety, while also increasing alertness under conditions of monotonous work and relaxation. We also discuss its protective effects against toxic agents at recommended doses, as well as its safety and potential toxicity. Overall, this review provides the latest findings and insights into the properties and clinical effects of peppermint/menthol and highlights its potential as a natural therapeutic agent for various health conditions.

A synthetic thiol molecule releasing N-acetyl-l-cysteine and cysteamine drives early up-regulation of immunoproteasome subunits in the lymph nodes of mice infected with LP-BM5 leukemia retrovirus

Thiol molecules have been recently re-considered as drug candidates in viral infections because of their ability to induce redox changes which interfere with virus life cycle and modulate the host immune response. Little is known about the molecular mechanisms of their immunomodulatory properties. Here we show that I-152, a thiol molecule metabolized to release N-acetyl-l-cysteine and cysteamine and acting as a pro-glutathione agent, causes early up-regulation of immunoproteasome subunits in the lymph nodes of murine leukemia virus infected mice. This evidence suggests that the immunoproteasome may be modulated by thiol-based compounds with important implications in understanding redox-controlled immunoregulation.

Virus-mimicking nanosystems: from design to biomedical applications

Nanomedicine, as an interdisciplinary discipline involving the development and application of nanoscale materials and technologies, is rapidly developing under the impetus of bionanotechnology and has attracted a great deal of attention from researchers. Especially, with the global outbreak of COVID-19, the in-depth investigation of the infection mechanism of the viruses has made the study of virus-mimicking nanosystems (VMNs) a popular research topic. In this review, we initiate with a brief historical perspective on the emergence and development of VMNs for providing a comprehensive view of the field. Next, we present emerging design principles and functionalization strategies for fabricating VMNs in light of viral infection mechanisms. Then, we describe recent advances in VMNs in biology, with a major emphasis on representative examples. Finally, we summarize the opportunities and challenges that exist in this field, hoping to provide new insights and inspiration to develop VMNs for disease diagnosis and treatment and to attract the interest of more researchers from different fields.

Impact of Dietary Quality on Genital Oncogenic Human Papillomavirus Infection in Women

BACKGROUND

Most cervical cancers are directly linked to oncogenic or high-risk human papillomavirus (HR-HPV) infection. This study evaluates associations between diet quality and genital HPV infection in women.

METHODS

This study included 10 543 women from the 2003-2016 National Health and Nutrition Examination Survey. The outcome was the genital HPV infection status (HPV-negative, low-risk [LR] HPV, and HR-HPV). Dietary quality was evaluated using the Healthy Eating Index (HEI), in which a higher score indicates a better diet quality.

RESULTS

Women who did not consume total fruits (15.8%), whole fruits (27.5%), or green vegetables and beans (43%) had a significantly higher risk of HR-HPV infection than women who complied with the Dietary Guidelines for Americans (HR-HPV odds ratio = 1.76, 1.63, and 1.48 for a HEI score of 0 vs 5, respectively) after adjusting confounding factors. Similar results of these food components on LR-HPV infection were found. In addition, intake of whole grains and dairy was inversely associated with LR-HPV infection.

CONCLUSIONS

This study showed that women who did not eat fruits, dark-green vegetables, and beans had a higher risk of genital HR-HPV infection. Intake of these food components is suggested for women to prevent HPV carcinogenesis.

ECHOPvir: A Mixture of Echinacea and Hop Extracts Endowed with Cytoprotective, Immunomodulatory and Antiviral Properties

Respiratory viral infections continue to pose significant challenges, particularly for more susceptible and immunocompromised individuals. Nutraceutical strategies have been proposed as promising strategies to mitigate their impact and improve public health. In the present study, we developed a mixture of two hydroalcoholic extracts from the aerial parts of Echinacea purpurea (L.) Moench (ECP) and the cones of Humulus lupulus L. (HOP) that can be harnessed in the prevention and treatment of viral respiratory diseases. The ECP/HOP mixture (named ECHOPvir) was characterized for the antioxidant and cytoprotective properties in airway cells. Moreover, the immunomodulating properties of the mixture in murine macrophages against antioxidant and inflammatory stimuli and its antiviral efficacy against the PR8/H1N1 influenza virus were assayed. The modulation of the Nrf2 was also investigated as a mechanistic hypothesis. The ECP/HOP mixture showed a promising multitarget bioactivity profile, with combined cytoprotective, antioxidant, immunomodulating and antiviral activities, likely due to the peculiar phytocomplexes of both ECP and HOP, and often potentiated the effect of the single extracts. The Nrf2 activation seemed to trigger these cytoprotective properties and suggest a possible usefulness in counteracting the damage caused by different stressors, including viral infection. Further studies may strengthen the interest in this product and underpin its future nutraceutical applications.

Oxidative stress and ROS-mediated cellular events in RSV infection: potential protective roles of antioxidants

Respiratory syncytial virus (RSV), a member of the Pneumoviridae family, can cause severe acute lower respiratory tract infection in infants, young children, immunocompromised individuals and elderly people. RSV is associated with an augmented innate immune response, enhanced secretion of inflammatory cytokines, and necrosis of infected cells. Oxidative stress, which is mainly characterized as an imbalance in the production of reactive oxygen species (ROS) and antioxidant responses, interacts with all the pathophysiologic processes above and is receiving increasing attention in RSV infection. A gradual accumulation of evidence indicates that ROS overproduction plays an important role in the pathogenesis of severe RSV infection and serves as a major factor in pulmonary inflammation and tissue damage. Thus, antioxidants seem to be an effective treatment for severe RSV infection. This article mainly reviews the information on oxidative stress and ROS-mediated cellular events during RSV infection for the first time.

Benzoindolizidine Alkaloids Tylophorine and Lycorine and Their Analogues with Antiviral, Anti-Inflammatory, and Anticancer Properties: Promises and Challenges

Ongoing viral research, essential for public health due to evolving viruses, gains significance owing to emerging viral infections such as the SARS-CoV-2 pandemic. Marine and plant alkaloids show promise as novel potential pharmacological strategies. In this narrative review, we elucidated the potential of tylophorine and lycorine, two naturally occurring plant-derived alkaloids with a shared benzoindolizidine scaffold, as antiviral agents to be potentially harnessed against respiratory viral infections. Possible structure-activity relationships have also been highlighted. The substances and their derivatives were found to be endowed with powerful and broad-spectrum antiviral properties; moreover, they were able to counteract inflammation, which often underpins the complications of viral diseases. At last, their anticancer properties hold promise not only for advancing cancer research but also for mitigating the oncogenic effects of viruses. This evidence suggests that tylophorine and lycorine could effectively counteract the pathogenesis of respiratory viral disease and its harmful effects. Although common issues about the pharmacologic development of natural substances remain to be addressed, the collected evidence highlights a possible interest in tylophorine and lycorine as antiviral and/or adjuvant strategies and encourages future more in-depth pre-clinical and clinical investigations to overcome their drawbacks and harness their power for therapeutic purposes.

Protective effect of Salvia plebeia R. Br ethanol extract on UVB-induced skin photoaging in vitro and in vivo

BACKGROUND

UV exposure is one of the primary factors responsible for photoaging, causing the increase in matrix metalloproteinases (MMPs) and the reduction in collagen. Salvia plebeia R. Br (SP), as an herbaceous plant, contains abundant flavonoids and possesses excellent anti-inflammatory and antioxidant activities. This study aimed to investigate the photoprotective effects of SP on UVB-induced photodamage in immortalized human keratinocytes (HaCaTs) and Kunming mice, as well as its main active components such as homoplantaginin (HP).

METHODS

CCK-8 was applied to detect the cell viability in UVB-irradiated or non-irradiated HaCaTs. Commercial kits were used to evaluate the levels of ROS, MDA, SA-β-Gal, MMP-1, and IL-6. The expression of MAPK and TGF-β/Smad pathways was detected by western blot. HE and Masson's trichrome staining were performed to examine the epidermis thickness and collagen degradation of Kunming mice.

RESULTS

Our results found that SP and HP notably decreased UVB-induced ROS, MDA, and SA-β-Gal production, and inhibited MMP-1 and IL-6 secretion by inhibiting the MAPK signaling pathway. In addition, SP and HP significantly promoted type I procollagen synthesis by activation of TGF-β/Smad pathway. Consistently, the in vivo experiments also indicated that SP and HP had a photoprotective effect, which significantly reversed UVB-induced epidermis thickness and collagen degradation.

CONCLUSION

This study demonstrated that SP effectively could protect skin from UVB-induced photoaging, while HP acted as the active substance in SP. All these findings provided a new strategy for skin photoaging treatment.

Toxicity of the spike protein of COVID-19 is a redox shift phenomenon: A novel therapeutic approach

We previously demonstrated that most diseases display a form of anabolism due to mitochondrial impairment: in cancer, a daughter cell is formed; in Alzheimer's disease, amyloid plaques; in inflammation cytokines and lymphokines. The infection by Covid-19 follows a similar pattern. Long-term effects include redox shift and cellular anabolism as a result of the Warburg effect and mitochondrial dysfunction. This unrelenting anabolism leads to the cytokine storm, chronic fatigue, chronic inflammation or neurodegenerative diseases. Drugs such as Lipoic acid and Methylene Blue have been shown to enhance the mitochondrial activity, relieve the Warburg effect and increase catabolism. Similarly, coMeBining Methylene Blue, Chlorine dioxide and Lipoic acid may help reduce long-term Covid-19 effects by stimulating the catabolism.

Dietary and Serum Antioxidants Associated with Prostate-Specific Antigen for Middle-Aged and Older Men

High prostate-specific antigen (PSA) levels can indicate potential prostate problems and are a warning sign of prostate cancer. The impact of antioxidants on the PSA of generally healthy men is understudied. This study aims to evaluate 14 dietary and endogenous antioxidants associated with PSA levels for United States (US) men. We assessed 7398 men using the 2003-2010 US population-based National Health and Nutrition Examination Survey (NHANES). The PSA levels were categorized into three groups: Normal, borderline, and elevated levels. We performed analyses for middle-aged and older groups aged 40-64.9 and ≥65, respectively. The weighted multinomial regressions were performed to evaluate antioxidants associated with the PSA status. For results, 0.3% and 3.4% of middle-aged and older men, respectively, had elevated PSA (>10 ng/mL). Men with a higher serum albumin level had a lower risk of an elevated PSA, adjusting for age. The magnitude of albumin's impact on PSA is larger in middle-aged men than in older men (OR of elevated PSA = 0.82 and 0.90, respectively, interaction p = 0.002). Other antioxidants are not associated with PSA. Our findings support men with low serum albumin tend to have an elevated PSA level, so related interventions can be considered to decrease PSA for maintaining prostate health.

Free Radical and Viral Infection: A Review from the Perspective of Ferroptosis

Free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), play critical roles in various physiological activities such as cell differentiation, apoptosis, and vascular tension when existing in cells at low levels. However, excessive amounts of free radicals are harmful, causing DNA damage, lipid peroxidation, protein degeneration, and abnormal cell death. Certain viral infections induce cells to produce excessive free radicals, which in multiple ways help the virus to replicate, mature, and exit. Iron is a necessary element for many intracellular enzymes, involved in both cellular activities and viral replication. Ferroptosis, a programmed cell death mode distinct from apoptosis, necrosis, and pyroptosis, is characterized by lipid peroxide accumulation and damage to the antioxidant system, affecting many cellular processes. Viral infection commonly manifests as decreased glutathione (GSH) content and down-regulated glutathione peroxidase 4 (GPX4) activity, similar to ferroptosis. Recent studies have suggested a possible relationship among free radicals, viral infections and ferroptosis. This review aims to elucidate the molecular mechanism linking free radicals and ferroptosis during viral infections and provide a new theoretical basis for studying viral pathogenesis and control.

Dietary Olive Leaf Extract Differentially Modulates Antioxidant Defense of Normal and Aeromonas hydrophila-Infected Common Carp (Cyprinus carpio) via Keap1/Nrf2 Pathway Signaling: A Phytochemical and Biological Link

Olive leaves are an immense source of antioxidant and antimicrobial bioactive constituents. This study investigated the effects of dietary incorporation of olive leaf extract (OLE) on the growth performance, hematobiochemical parameters, immune response, antioxidant defense, histopathological changes, and some growth- and immune-related genes in the common carp (Cyprinus carpio). A total of 180 fish were allocated into four groups with triplicate each. The control group received the basal diet without OLE, while the other three groups were fed a basal diet with the OLE at 0.1, 0.2, and 0.3%, respectively. The feeding study lasted for 8 weeks, then fish were challenged with Aeromonas hydrophila. The results revealed that the group supplied with the 0.1% OLE significantly exhibited a higher final body weight (FBW), weight gain (WG%), and specific growth rate (SGR) with a decreased feed conversion ratio (FCR) compared to the other groups (p < 0.05). An increase in immune response was also observed in the fish from this group, with higher lysosome activity, immunoglobulin (IgM), and respiratory burst than nonsupplemented fish, both before and after the A. hydrophila challenge (p < 0.05). Similarly, the supplementation of the 0.1% OLE also promoted the C. carpio's digestive capacity pre- and post-challenge, presenting the highest activity of protease and alkaline phosphatase (p < 0.05). In addition, this dose of the OLE enhanced fish antioxidant capacity through an increase in the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and decreased hepatic lipid peroxidation end products (malondialdehyde-MDA), when compared to the control group, both pre- and post-infection (p < 0.05). Concomitantly with the superior immune response and antioxidant capacity, the fish fed the 0.1% OLE revealed the highest survival rate after the challenge with A. hydrophila (p < 0.05). A significant remarkable upregulation of the hepatic sod, nrf2, and protein kinase C transcription levels was detected as a vital approach for the prevention of both oxidative stress and inflammation compared to the infected unsupplied control group (p < 0.05). Interestingly, HPLC and UPLC-ESI-MS/MS analyses recognized that oleuropein is the main constituent (20.4%) with other 45 compounds in addition to tentative identification of two new compounds, namely oleuroside-10-carboxylic acid (I) and demethyl oleuroside-10-carboxylic acid (II). These constituents may be responsible for the OLE exerted potential effects. To conclude, the OLE at a dose range of 0.66-0.83 g/kg w/w can be included in the C. carpio diet to improve the growth, antioxidant capacity, and immune response under normal health conditions along with regulating the infection-associated pro-inflammatory gene expressions, thus enhancing resistance against A. hydrophila.

Nontoxic Levels of Se-Containing Compounds Increase Survival by Blocking Oxidative and Inflammatory Stresses via Signal Pathways Whereas High Levels of Se Induce Apoptosis

Selenium is a main group element and an essential trace element in human health. It was discovered in selenocysteine (SeC) by Stadtman in 1974. SeC is an encoded natural amino acid hailed as the 21st naturally occurring amino acid (U) present in several enzymes and which exquisitely participates in redox biology. As it turns out, selenium bears a U-shaped toxicity curve wherein too little of the nutrient present in biology leads to disorders; concentrations that are too great, on the other hand, pose toxicity to biological systems. In light of many excellent previous reviews and the corpus of literature, we wanted to offer this current review, in which we present aspects of the clinical and biological literature and justify why we should further investigate Se-containing species in biological and medicinal contexts, especially small molecule-containing species in biomedical research and clinical medicine. Of central interest is how selenium participates in biological signaling pathways. Several clinical medical cases are recounted; these reports are mainly pertinent to human cancer and changes in pathology and cases in which the patients are often terminal. Selenium was an option chosen in light of earlier chemotherapeutic treatment courses which lost their effectiveness. We describe apoptosis, and also ferroptosis, and senescence clearly in the context of selenium. Other contemporary issues in research also compelled us to form this review: issues with CoV-2 SARS infection which abound in the literature, and we described findings with human patients in this context. Laboratory scientific studies and clinical studies dealing with two main divisions of selenium, organic (e.g., methyl selenol) or inorganic selenium (e.g., sodium selenite), are discussed. The future seems bright with the research and clinical possibilities of selenium as a trace element, whose recent experimental clinical treatments have so far involved dosing simply and inexpensively over a set of days, amounts, and time intervals.

Reprogramming M1-to-M2 Phenotype to Alleviate Inflammation: Using Liposomal Curcumin as a Tool to Redefine Macrophage Functionality

The versatile nature of macrophages and their ability to switch between various activation states plays a pivotal role in both promoting and inhibiting inflammatory processes. In pathological inflammatory conditions, classically activated M1 macrophages are often associated with initiating and maintaining inflammation, while alternatively activated M2 macrophages are linked to the resolution of chronic inflammation. Achieving a favorable equilibrium between M1 and M2 macrophages is crucial for mitigating inflammatory environments in pathological conditions. Polyphenols are known to have strong inherent antioxidative capabilities, and curcumin has been found to reduce macrophage inflammatory reactions. However, its therapeutic efficacy is compromised due to its poor bioavailability. The present study aims to harness the properties of curcumin by loading it in nanoliposomes and enhancing the M1-to-M2 macrophage polarization. A stable liposome formulation was achieved at 122.1 ± 0.08 nm, and a sustained kinetic release of curcumin was observed within 24 h. The nanoliposomes were further characterized using TEM, FTIR, and XRD, and the morphological changes in macrophage cells, RAW264.7, were observed in SEM, indicating a distinct M2-type phenotype after the treatment with liposomal curcumin. ROS may partially control macrophage polarization and be observed to decrease after treatment with liposomal curcumin. The nanoliposomes were able to successfully internalize in the macrophage cells, and an enhanced expression of ARG-1 and CD206 with a decrease in iNOS, CD80, and CD86 levels suggested the polarization of LPS-activated macrophages toward the M2 phenotype. Also, liposomal curcumin treatment dose-dependently inhibited TNF-α, IL-2, IFN-γ, and IL-17A at secretory levels and simultaneously increased the levels of cytokines like IL-4, IL-6, and IL-10.

Progress in the Treatment of High Altitude Cerebral Edema: Targeting REDOX Homeostasis

With the increasing of altitude activities from low-altitude people, the study of high altitude cerebral edema (HACE) has been revived. HACE is a severe acute mountain sickness associated with exposure to hypobaric hypoxia at high altitude, often characterized by disturbance of consciousness and ataxia. As for the pathogenesis of HACE, previous studies suggested that it might be related to the disorder of cerebral blood flow, the destruction of blood-brain barrier and the injury of brain parenchyma cells caused by inflammatory factors. In recent years, studies have confirmed that the imbalance of REDOX homeostasis is also involved in the pathogenesis of HACE, which mainly leads to abnormal activation of microglia and destruction of tight junction of vascular endothelial cells through the excessive production of mitochondrial-related reactive oxygen species. Therefore, this review summarizes the role of REDOX homeostasis and the potential of the treatment of REDOX homeostasis in HACE, which is of great significance to expand the understanding of the pathogenesis of HACE. Moreover, it will also be helpful to further study the possible therapy of HACE related to the key link of REDOX homeostasis.

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.

Inhibition of H1N1 Influenza Virus-induced Apoptosis by Ebselen Through ROS-mediated ATM/ATR Signaling Pathways

Influenza A viruses can cause global outbreaks and seasonal pandemics. However, the use of conventional anti-influenza drugs leads to an increase in drug-resistant mutations in influenza viruses worldwide. Therefore, numerous studies have focused on developing effective anti-influenza drugs. It is feasible to treat influenza by targeting influenza-mediated oxidative damage. Ebselen is a synthetic organoselenium compound which provides glutathione peroxidase-like activity. It has been shown to play a role in anti-influenza therapy, but the mechanism remains to be further explored. This experiment verified the anti-influenza effect of ebselen. CCK-8 and PCR showed that ebselen had a significant inhibitory effect on virus replication compared with the virus group. In addition, the mechanistic investigations revealed that ebselen could inhibit influenza-mediated apoptosis, mitochondrial damage, accumulation of reactive oxygen species, and DNA breakage. At the same time, ebselen significantly inhibited the phosphorylation of ATM and ATR and promoted the activation of PARP and Caspase-3. Ebselen, on the other hand, reduced the inflammatory response caused by influenza. These results suggest that ebselen is a promising inhibitor for H1N1.

S100 proteins in cardiovascular diseases

Cardiovascular diseases have become a serious threat to human health and life worldwide and have the highest fatality rate. Therefore, the prevention and treatment of cardiovascular diseases have become a focus for public health experts. The expression of S100 proteins is cell- and tissue-specific; they are implicated in cardiovascular, neurodegenerative, and inflammatory diseases and cancer. This review article discusses the progress in the research on the role of S100 protein family members in cardiovascular diseases. Understanding the mechanisms by which these proteins exert their biological function may provide novel concepts for preventing, treating, and predicting cardiovascular diseases.

Anti-COVID-19 Potential of Ellagic Acid and Polyphenols of Punica granatum L

Pomegranate (Punica granatum L.) is a rich source of polyphenols, including ellagitannins and ellagic acid. The plant is used in traditional medicine, and its purified components can provide anti-inflammatory and antioxidant activity and support of host defenses during viral infection and recovery from disease. Current data show that pomegranate polyphenol extract and its ellagitannin components and metabolites exert their beneficial effects by controlling immune cell infiltration, regulating the cytokine secretion and reactive oxygen and nitrogen species production, and by modulating the activity of the NFκB pathway. In vitro, pomegranate extracts and ellagitannins interact with and inhibit the infectivity of a range of viruses, including SARS-CoV-2. In silico docking studies show that ellagitannins bind to several SARS-CoV-2 and human proteins, including a number of proteases. This warrants further exploration of polyphenol-viral and polyphenol-host interactions in in vitro and in vivo studies. Pomegranate extracts, ellagitannins and ellagic acid are promising agents to target the SARS-CoV-2 virus and to restrict the host inflammatory response to viral infections, as well as to supplement the depleted host antioxidant levels during the stage of recovery from COVID-19.

Immunomodulatory Role of Microelements in COVID-19 Outcome: a Relationship with Nutritional Status

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). SARS-CoV-2 infection can activate innate and adaptive immune responses and result in massive inflammatory responses in the disease. A comprehensive understanding of the participation of micronutrients in the immune response to COVID-19 will allow the creation of prevention and supplementation scenarios in malnutrition states. Microelement deficiency can be decisive in the progression of diseases and their optimal levels can act as protective factors, helping to maintain homeostasis. Vitamin A, B, D, selenium, zinc, and copper, through their complementary and synergistic effects, allow the components of innate and adaptive immunity to counteract infections like those occurring in the respiratory tract.Thus, alterations in nutritional status are related to metabolic diseases, systemic inflammation, and deterioration of the immune system that alter the response against viral infections, such as COVID-19. The aim of this review is to describe the micronutrients that play an important role as immunomodulators and its relationship between malnutrition and the development of respiratory infections with an emphasis on severe and critical COVID-19. We conclude that although an unbalanced diet is not the only risk factor that predisposes to COVID-19, a correct and balanced diet, which provides the optimal amount of micronutrients and favors an adequate nutritional status, could confer beneficial effects for prevention and improvement of clinical results. The potential usefulness of micronutrient supplementation in special cases is highlighted.

Inflammation Related to Association of Low Uric Acid and Progression to Severe Disease in Patients Hospitalized for Non-Severe Coronavirus Disease 2019

Uric acid has antioxidant properties. To examine whether a low uric acid level is associated with severe coronavirus disease 2019 (COVID-19) progression via inflammation, alveolar damage, and/or coagulation abnormality, a retrospective observational study of 488 patients with non-severe COVID-19 and serum uric acid level ≤7 mg/dL at admission was conducted. Serum C-reactive protein (CRP), serum Krebs von den Lungen 6 (KL-6), and plasma D-dimer levels were also measured as markers of inflammation, alveolar damage, and coagulation abnormality, respectively. Median values for uric acid, CRP, KL-6, and D-dimer at admission were 4.4 mg/dL, 3.33 mg/dL, 252.0 U/mL, and 0.8 µg/mL, respectively. Among the total cohort, 95 (19.5%) progressed to severe COVID-19 with a median (interquartile range) time of 7 (4–14) days. Multivariable Cox proportional hazards regression analysis showed that low uric acid level was associated with a higher rate of severe COVID-19 progression. However, uric acid level was inversely associated with CRP level, and the association between the level of uric acid and severe COVID-19 progression was significantly different with and without CRP level inclusion. In contrast, no such association was found for KL-6 or D-dimer level. Low uric acid may contribute to severe COVID-19 progression via increased inflammation in subjects without hyperuricemia.

Influenza virus replication is affected by glutaredoxin1-mediated protein deglutathionylation

Several redox modifications have been described during viral infection, including influenza virus infection, but little is known about glutathionylation and this respiratory virus. Glutathionylation is a reversible, post-translational modification, in which protein cysteine forms transient disulfides with glutathione (GSH), catalyzed by cellular oxidoreductases and in particular by glutaredoxin (Grx). We show here that (i) influenza virus infection induces protein glutathionylation, including that of viral proteins such as hemagglutinin (HA); (ii) Grx1-mediated deglutathionylation is important for the viral life cycle, as its inhibition, either with an inhibitor of its enzymatic activity or by siRNA, decreases viral replication. Overall these data contribute to the characterization of the complex picture of redox regulation of the influenza virus replication cycle and could help to identify new targets to control respiratory viral infection.

Development of spray-dried N-acetylcysteine dry powder for inhalation

N-acetylcysteine (NAC) has both antioxidant and immunomodulatory activities and has been used as adjuvant therapy in several viral infections. Recently, NAC attracted attention for its possible role in reducing the affinity of the spike protein receptor binding domain to angiotensin-converting enzyme (ACE2) receptors. Since only NAC solutions are available for inhalation, the purpose of the work was to develop a NAC dry powder for inhalation using mannitol or leucine as excipient. The powder was successfully produced using co-spray-drying with leucine. ATR-FTIR analyses evidenced spectral variations ascribed to the formation of specific interactions between NAC and leucine. This effect on the NAC environment was not evident for NAC-mannitol powders, but mannitol was in a different polymorphic form compared to the supplied material. Both the feedstock concentration and the leucine content have an impact on the powder aerodynamic features. In particular, to maximize the respirable fraction, it is preferable to produce the powder starting from a 0.5 % w/v feedstock solution using 33 to 50 % w/w leucine content. The NAC-leucine powder was stable for ten months maintaining NAC content of 50 % (w/w) and about 200 μg of NAC was able to deposit on a transwell insert, useful for future in vitro studies.

Oxidative profile, inflammatory responses and δ-aminolevulinate dehydratase enzyme activity in influenza B virus infection

The aim of the current study was to determine the activity of the delta-aminolevulinate dehydratase (δ-ALA-D) enzyme, oxidative stress biomarkers and the expression of cytokines in those infected with influenza B virus (IBV). To evaluate the activity of the δ-ALA-D enzyme, lipid peroxidation was estimated as levels of thiobarbituric acid reactive substances, protein and non-protein thiol groups, ferric-reducing antioxidant power (FRAP), vitamin C concentration and cytokine levels in IBV-infected individuals (n  = 50) and a control group (n = 30). δ-ALA-D activity was significantly lower in IBV-infected individuals compared with controls, as well as levels of thiols, vitamin C and FRAP. Lipid peroxidation and cytokine levels of IL-6, IL-10, IL-17A and IFN-y were statistically higher in the IBV group. In conclusion, we found evidence of the generation of oxidants, the depletion of the antioxidant system, decrease in the activity of the δ-ALA-D enzyme and an increase in the synthesis of cytokines, thus contributing to a better understanding of oxidative and inflammatory pathways during IBV infection.

Transcription factor Nrf2 as a potential therapeutic target for COVID-19

The coronavirus disease 2019 (COVID-19) is caused by a novel severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2). Critically ill patients with SARS-COV-2 infection frequently exhibit signs of high oxidative stress and systemic inflammation, which accounts for most of the mortality. Antiviral strategies to inhibit the pathogenic consequences of COVID-19 are urgently required. The nuclear factor erythroid 2-related transcription factor (Nrf2) is a transcription factor that is involved in antioxidant and anti-inflammatory defense in several tissues and cells. This review tries to present an overview of the role of Nrf2 in the treatment of COVID-19.

Multicomponent Synthesis of Diaminopurine and Guanine PNA's Analogues Active against Influenza A Virus from Prebiotic Compounds

Peptide nucleic acids (PNAs) play a key role in prebiotic chemistry as a chimera between RNA and proteins. We developed an alternative synthesis of bioactive PNA's diaminopurine and guanine analogues from prebiotic compounds, such as aminomalononitrile (AMN), urea, and guanidine, using a two-step multicomponent microwave-assisted and solvent-free approach in the presence of selected amino acids. The novel derivatives showed selective inhibitory activity against influenza virus A/Puerto Rico/8/34 H1N1 encompassing the range of nanomolar activity. Derivatives decorated with the tyrosine residue showed the highest inhibitory activity against the virus.

Recent Developments in the Understanding of Immunity, Pathogenesis and Management of COVID-19

Coronaviruses represent a diverse family of enveloped positive-sense single stranded RNA viruses. COVID-19, caused by Severe Acute Respiratory Syndrome Coronavirus-2, is a highly contagious respiratory disease transmissible mainly via close contact and respiratory droplets which can result in severe, life-threatening respiratory pathologies. It is understood that glutathione, a naturally occurring antioxidant known for its role in immune response and cellular detoxification, is the target of various proinflammatory cytokines and transcription factors resulting in the infection, replication, and production of reactive oxygen species. This leads to more severe symptoms of COVID-19 and increased susceptibility to other illnesses such as tuberculosis. The emergence of vaccines against COVID-19, usage of monoclonal antibodies as treatments for infection, and implementation of pharmaceutical drugs have been effective methods for preventing and treating symptoms. However, with the mutating nature of the virus, other treatment modalities have been in research. With its role in antiviral defense and immune response, glutathione has been heavily explored in regard to COVID-19. Glutathione has demonstrated protective effects on inflammation and downregulation of reactive oxygen species, thereby resulting in less severe symptoms of COVID-19 infection and warranting the discussion of glutathione as a treatment mechanism.

Role of Nuclear Factor Erythroid 2 (Nrf2) in the Recovery of Long COVID-19 Using Natural Antioxidants: A Systematic Review

Coronavirus disease 2019 (COVID-19) is an infectious disease with approximately 517 million confirmed cases, with the average number of cases revealing that patients recover immediately without hospitalization. However, several other cases found that patients still experience various symptoms after 3–12 weeks, which is known as a long COVID syndrome. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can activate nuclear factor kappa beta (NF-κβ) and unbind the nuclear factor erythroid 2-related factor 2 (Nrf2) with Kelch-like ECH-associated protein 1 (Keap1), causing inhibition of Nrf2, which has an important role in antioxidant response and redox homeostasis. Disrupting the Keap1–Nrf2 pathway enhances Nrf2 activity, and has been identified as a vital approach for the prevention of oxidative stress and inflammation. Hence, natural antioxidants from various sources have been identified as a promising strategy to prevent oxidative stress, which plays a role in reducing the long COVID-19 symptoms. Oxygen-rich natural antioxidant compounds provide an effective Nrf2 activation effect that interact with the conserved amino acid residues in the Keap1-binding pocket, such as Ser602, Ser363, Ser508, and Ser555. In this review, the benefits of various natural antioxidant compounds that can modulate the Nrf2 signaling pathway, which is critical in reducing and curing long COVID-19, are highlighted and discussed.

Neomycin inhibits Megalocytivirus infection in fish by antagonizing the increase of intracellular reduced glutathione

Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the Megalocytivirus genus that infects a number of marine and freshwater fishes, causing huge economic losses in aquaculture. The ISKNV infection leads to increase of reducing power in cells. As the antibiotic neomycin can promote the production of reactive oxygen species (ROS) in animal cells, in the current study, the potential therapeutic effect of neomycin on ISKNV infection was explored. We showed that neomycin could decrease the reducing power in cultured MFF-1 cells and inhibit ISKNV infection by antagonizing the shift of the cellular redox balance toward reduction. In vivo experiments further demonstrated that neomycin treatment significantly suppresses ISKNV infection in mandarin fish. Expression of the major capsid protein (MCP) and the proportion of infected cells in tissues were down-regulated after neomycin treatment. Furthermore, neomycin showed complex effects on expression of a set of antiviral related genes of the host. Taking together, the current study suggested that the viral-induced redox imbalance in the infected cells could be used as a target for suppressing ISKNV infection. Neomycin can be potentially utilized for therapeutic treatment of Megalocytivirus diseases by antagonizing intracellular redox changes.

Hydrogen Sulfide Donor GYY4137 Rescues NRF2 Activation in Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) can cause severe respiratory illness in infants, immunocompromised, and older adults. Despite its burden, no vaccine or specific treatment is available. RSV infection is associated with increased reactive oxygen species (ROS) production, degradation of the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), and decreased antioxidant enzymes (AOEs), leading to oxidative damage and lung injury. Hydrogen sulfide (H2S) is an endogenous gaseous molecule that plays a physiological role in numerous cellular processes and a protective role in multiple pathological conditions, displaying vasoactive, cytoprotective, anti-inflammatory, and antioxidant activities. H2S can promote NRF2 activation through the sulfhydration of Kelch-like ECH-associated protein 1, the cytoplasmic repressor of NRF2. Here we investigated whether increasing cellular H2S levels could rescue NRF2 and NRF2-dependent gene expression in RSV-infected primary airway epithelial cells. We found that treatment with the H2S donor GYY4137 significantly increased NRF2 levels and AOEs gene expression by decreasing KEAP1 levels, and by modulating pathways involved in RSV-induced NRF2 degradation, such as NRF2 ubiquitination, and promyelocytic leukemia (PML) protein levels. These results suggest that the administration of exogenous H2S can positively impact the altered redox balance associated with RSV infection, which represents an important determinant of RSV-induced lung disease.

How Aging and Oxidative Stress Influence the Cytopathic and Inflammatory Effects of SARS-CoV-2 Infection: The Role of Cellular Glutathione and Cysteine Metabolism

SARS-CoV-2 infection can cause a severe respiratory distress syndrome with inflammatory and thrombotic complications, the severity of which increases with patients’ age and presence of comorbidity. The reasons for an age-dependent increase in the risk of severe COVID-19 could be many. These include defects in the homeostatic processes that control the cellular redox and its pivotal role in sustaining the immuno-inflammatory response to the host and the protection against oxidative stress and tissue degeneration. Pathogens may take advantage of such age-dependent abnormalities. Alterations of the thiol redox balance in the lung tissue and lining fluids may influence the risk of infection, and the host capability to respond to pathogens and to avoid severe complications. SARS-CoV-2, likewise other viruses, such as HIV, influenza, and HSV, benefits in its replication cycle of pro-oxidant conditions that the same viral infection seems to induce in the host cell with mechanisms that remain poorly understood. We recently demonstrated that the pro-oxidant effects of SARS-CoV-2 infection are associated with changes in the cellular metabolism and transmembrane fluxes of Cys and GSH. These appear to be the consequence of an increased use of Cys in viral protein synthesis and to ER stress pathway activation that interfere with transcription factors, as Nrf2 and NFkB, important to coordinate the metabolism of GSH with other aspects of the stress response and with the pro-inflammatory effects of this virus in the host cell. This narrative review article describes these cellular and molecular aspects of SARS-CoV-2 infection, and the role that antivirals and cytoprotective agents such as N-acetyl cysteine may have to limit the cytopathic effects of this virus and to recover tissue homeostasis after infection.

COVID-19 and Parkinson's Disease: Possible Links in Pathology and Therapeutics

The outbreak of SARs-CoV-2 with emerging new variants is leading to global health crisis and has brought a major concern for patients with comorbidities. Parkinson's disease (PD) is a motor neurodegenerative disease involving various metabolic and psychological ailments along with the common occurrence of hyposmia as observed in COVID-19 patients. In addition, the observed surplus inflammatory responses in both diseases are also alarming. Alongside, angiotensin-converting enzyme 2 (ACE2) receptor, essentially required by SARS-CoV-2 to enter the cell and dopamine decarboxylase (DDC), required for dopamine synthesis is known to co-regulate in the non-neuronal cells. Taken together, these conditions suggested the probable reciprocal pathological relation between COVID-19 and PD and also suggested that during comorbidities, the disease diagnosis and therapeutics are critical and may engender severe health complications. In this review, we discuss various events and mechanisms which may have implications for the exacerbation of PD conditions and must be taken into account during the treatment of patients.

Poxviruses package viral redox proteins in lateral bodies and modulate the host oxidative response

All poxviruses contain a set of proteinaceous structures termed lateral bodies (LB) that deliver viral effector proteins into the host cytosol during virus entry. To date, the spatial proteotype of LBs remains unknown. Using the prototypic poxvirus, vaccinia virus (VACV), we employed a quantitative comparative mass spectrometry strategy to determine the poxvirus LB proteome. We identified a large population of candidate cellular proteins, the majority being mitochondrial, and 15 candidate viral LB proteins. Strikingly, one-third of these are VACV redox proteins whose LB residency could be confirmed using super-resolution microscopy. We show that VACV infection exerts an anti-oxidative effect on host cells and that artificial induction of oxidative stress impacts early and late gene expression as well as virion production. Using targeted repression and/or deletion viruses we found that deletion of individual LB-redox proteins was insufficient for host redox modulation suggesting there may be functional redundancy. In addition to defining the spatial proteotype of VACV LBs, these findings implicate poxvirus redox proteins as potential modulators of host oxidative anti-viral responses and provide a solid starting point for future investigations into the role of LB resident proteins in host immunomodulation.

Swine influenza virus triggers ferroptosis in A549 cells to enhance virus replication

Background

Recently, Influenza A virus (IAV) has been shown to activate several programmed cell death pathways that play essential roles in host defense. Indeed, cell death caused by viral infection may be mediated by a mixed pattern of cell death instead of a certain single mode. Ferroptosis is a novel form of regulated cell death (RCD) that is mainly mediated by iron-dependent lipid peroxidation. Based on the proteomic data, we wondered whether IAV causes ferroptosis in host cells.

Method

In this study, a quantitative proteomics approach based on an iTRAQ combined with LC–MS/MS was used to profile proteins expressed in A549 cells infected with H1N1 swine influenza virus (SIV). Meanwhile, we measured the intracellular iron content, reactive oxygen species (ROS) release and lipid peroxidation in response to SIV infection. Finally, a drug experiment was conducted to investigate the effects of ferroptosis on modulating SIV survival.

Results

The bioinformatics analysis revealed several proteins closely relevant to iron homeostasis and transport, and the ferroptosis signaling pathway are highly enriched in response to SIV infection. In our experiment, aberrant expression of iron-binding proteins disrupted labile iron uptake and storage after SIV infection. Meanwhile, SIV infection inhibited system the Xc⁻/GPX4 axis resulting in GSH depletion and the accumulation of lipid peroxidation products. Notably, cell death caused by SIV as a result of iron-dependent lipid peroxidation can be partially rescued by ferroptosis inhibitor. Additionally, blockade of the ferroptotic pathway by ferrostatin-1 (Fer-1) treatment decreased viral titers and inflammatory response.

Conclusions

This study revealed a new mode of cell death induced by IAV infection, and our findings might improve the understanding of the underlying mechanism involved in the interaction of virus and host cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-022-01825-y.

Antioxidant Genetic Profile Modifies Probability of Developing Neurological Sequelae in Long-COVID

Understanding the sequelae of COVID-19 is of utmost importance. Neuroinflammation and disturbed redox homeostasis are suggested as prevailing underlying mechanisms in neurological sequelae propagation in long-COVID. We aimed to investigate whether variations in antioxidant genetic profile might be associated with neurological sequelae in long-COVID. Neurological examination and antioxidant genetic profile (SOD2, GPXs and GSTs) determination, as well as, genotype analysis of Nrf2 and ACE2, were conducted on 167 COVID-19 patients. Polymorphisms were determined by the appropriate PCR methods. Only polymorphisms in GSTP1AB and GSTO1 were independently associated with long-COVID manifestations. Indeed, individuals carrying GSTP1 Val or GSTO1 Asp allele exhibited lower odds of long-COVID myalgia development, both independently and in combination. Furthermore, the combined presence of GSTP1 Ile and GSTO1 Ala alleles exhibited cumulative risk regarding long-COVID myalgia in carriers of the combined GPX1 LeuLeu/GPX3 CC genotype. Moreover, individuals carrying combined GSTM1-null/GPX1LeuLeu genotype were more prone to developing long-COVID “brain fog”, while this probability further enlarged if the Nrf2 A allele was also present. The fact that certain genetic variants of antioxidant enzymes, independently or in combination, affect the probability of long-COVID manifestations, further emphasizes the involvement of genetic susceptibility when SARS-CoV-2 infection is initiated in the host cells, and also months after.

Modulating the Antioxidant Response for Better Oxidative Stress-Inducing Therapies: How to Take Advantage of Two Sides of the Same Medal?

Oxidative stress-inducing therapies are characterized as a specific treatment that involves the production of reactive oxygen and nitrogen species (RONS) by external or internal sources. To protect cells against oxidative stress, cells have evolved a strong antioxidant defense system to either prevent RONS formation or scavenge them. The maintenance of the redox balance ensures signal transduction, development, cell proliferation, regulation of the mechanisms of cell death, among others. Oxidative stress can beneficially be used to treat several diseases such as neurodegenerative disorders, heart disease, cancer, and other diseases by regulating the antioxidant system. Understanding the mechanisms of various endogenous antioxidant systems can increase the therapeutic efficacy of oxidative stress-based therapies, leading to clinical success in medical treatment. This review deals with the recent novel findings of various cellular endogenous antioxidant responses behind oxidative stress, highlighting their implication in various human diseases, such as ulcers, skin pathologies, oncology, and viral infections such as SARS-CoV-2.

Inflammation and oxidative stress, the links between obesity and COVID-19: a narrative review

COVID-19, an acute respiratory disease caused by SARS-CoV-2, has rapidly become a pandemic. On the other hand, obesity is also reaching dramatic dimensions and it is a risk factor for morbidity and premature mortality. Obesity has been linked to a high risk of serious-associated complications to COVID-19, due to the increased risk of concomitant chronic diseases, which highlights the health public relevance of the topic. Obese subjects have a pro-inflammatory environment, which can further exacerbate COVID-19-induced inflammation and oxidative stress, explaining the increased risk of serious complications in these patients. Another factor that favors infection in obese patients is the high expression of ACE2 receptors in the adipose tissue. The negative impact of COVID-19 in obesity is also associated with a decrease in respiratory function, the concurrence of multiple comorbidities, a low-degree chronic inflammatory state, immunocompromised situation, and therefore a higher rate of hospitalization, mechanical ventilation, in-hospital complications such as pneumonia, and death. In this review, the link between obesity and COVID-19 was analyzed, exploring the potential common mechanisms in both diseases, with special attention to oxidative stress and inflammation, due to the crucial role of both pathways in the development of the disease.

Prospective two‐arm study of testicular function in patients with COVID‐19

Background

The COVID‐19 pandemic has led the international community to conduct extensive research into potential negative effects of the disease on multiple organs and systems in the human body. One of the most discussed areas is potential of the virus to compromise the testicular function. However, the lack of prospective studies on this topic makes it impossible to draw reliable conclusions on whether the disease affects the male reproductive system and, if so, to what extent.

Objectives

The current trial is aimed at investigating the effect of SARS‐CoV‐2 on the testicular function, hormone levels and determining the extent of impact on spermatogenesis and damage to testicular tissue.

Materials and methods

This prospective study included healthy controls and cases of patients suffering from viral pneumonia based on chest computed tomography (CT) and a positive SARS‐CoV‐2 throat swab exhibited moderate symptoms (World Health Organization (WHO) classification). Epidemiological, clinical, laboratory and ultrasound data were collected. A semen analysis was performed in cases during their hospital stay and 3 months after the discharge home. We also assessed the testicles obtained during autopsies of patients who died of COVID‐19 (n = 20).

Results

A total of 88 participants were included (44 controls and 44 cases). Blood testosterone levels were significantly decreased in 27.3% of the cases (12/44). The mean level (7.3±2.7 nmol/L) was lower than that in the healthy controls (13.5±5.2 nmol/L, p < 0.001). An increase in luteinizing hormone (LH) and follicle‐stimulating hormone (FSH) was also detected compared to the healthy controls (p = 0.04 and p = 0.002). The semen analysis revealed decreased motility in COVID‐19 patients (p = 0.001), and a higher number of immobile sperm (during COVID‐19: 58.8% and at 3 months 47.4%, p = 0.005). All parameters returned to normal at 3 months after discharge. Direct mixed agglutination reaction (MAR) test at 3 months showed an increase of Ig A (p = 0.03). In the majority of autopsies (18/20), structural disorders of the testicular tissue, with signs of damage to germ cells were observed.

Discussion and conclusion

COVID‐19 and its management strategies significantly affect male hormone levels and sperm quality at the onset of the disease. Postmortem examination of testicular tissue confirmed inflammation and viral infiltration of the testicles. However, in patients with moderate to severe disease, the studied parameters of the testicular function returned to normal values within 3 months.

Influenza Virus Down-Modulates G6PD Expression and Activity to Induce Oxidative Stress and Promote Its Replication

Influenza virus infection induces oxidative stress in host cells by decreasing the intracellular content of glutathione (GSH) and increasing reactive oxygen species (ROS) level. Glucose-6-phosphate dehydrogenase (G6PD) is responsible for the production of reducing equivalents of nicotinamide adenine dinucleotide phosphate (NADPH) that is used to regenerate the reduced form of GSH, thus restoring redox homeostasis. Cells deficient in G6PD display elevated levels of ROS and an increased susceptibility to viral infection, although the consequences of G6PD modulation during viral infection remain to be elucidated. In this study, we demonstrated that influenza virus infection decreases G6PD expression and activity, resulting in an increase in oxidative stress and virus replication. Moreover, the down regulation of G6PD correlated with a decrease in the expression of nuclear factor erythroid 2-related factor 2 (NRF2), a key transcription factor that regulates the expression of the antioxidant response gene network. Also down-regulated in influenza virus infected cells was sirtuin 2 (SIRT2), a NADPH-dependent deacetylase involved in the regulation of G6PD activity. Acetylation of G6PD increased during influenza virus infection in a manner that was strictly dependent on SIRT2 expression. Furthermore, the use of a pharmacological activator of SIRT2 rescued GSH production and NRF2 expression, leading to decreased influenza virus replication. Overall, these data identify a novel strategy used by influenza virus to induce oxidative stress and to favor its replication in host cells. These observations furthermore suggest that manipulation of metabolic and oxidative stress pathways could define new therapeutic strategies to interfere with influenza virus infection.

"LONG COVID"-A hypothesis for understanding the biological basis and pharmacological treatment strategy

Infection of humans with SARS‐CoV‐2 virus causes a disease known colloquially as “COVID‐19” with symptoms ranging from asymptomatic to severe pneumonia. Initial pathology is due to the virus binding to the ACE‐2 protein on endothelial cells lining blood vessels and entering these cells in order to replicate. Viral replication causes oxidative stress due to elevated levels of reactive oxygen species. Many (~60%) of the infected people appear to have eliminated the virus from their body after 28 days and resume normal activity. However, a significant proportion (~40%) experience a variety of symptoms (loss of smell and/or taste, fatigue, cough, aching pain, “brain fog,” insomnia, shortness of breath, and tachycardia) after 12 weeks and are diagnosed with a syndrome named “LONG COVID.” Longitudinal clinical studies in a group of subjects who were infected with SARS‐CoV‐2 have been compared to a non‐infected matched group of subjects. A cohort of infected subjects can be identified by a battery of cytokine markers to have persistent, low level grade of inflammation and often self‐report two or more troubling symptoms. There is no drug that will relieve their symptoms effectively. It is hypothesized that drugs that activate the intracellular transcription factor, nuclear factor erythroid‐derived 2‐like 2 (NRF2) may increase the expression of enzymes to synthesize the intracellular antioxidant, glutathione that will quench free radicals causing oxidative stress. The hormone melatonin has been identified as an activator of NRF2 and a relatively safe chemical for most people to ingest chronically. Thus, it is an option for consideration of re‐purposing studies in “LONG COVID” subjects experiencing insomnia, depression, fatigue, and “brain fog” but not tachycardia. Appropriately designed clinical trials are required to evaluate melatonin.

Association Between Plasma Redox State/Mitochondria Function and a Flu-Like Syndrome/COVID-19 in the Elderly Admitted to a Long-Term Care Unit

Background/Aims: It is widely known that the imbalance between reactive oxygen species (ROS)/antioxidants and mitochondrial function could play a pivotal role in aging and in the physiopathology of viral infections. Here, we correlated the plasma oxidants/antioxidants levels of the elderly admitted to a long-term care (LTC) unit with clinical data in relation to flu-like disease/COVID-19. Moreover, in vitro we examined the effects of plasma on cell viability, ROS release and mitochondrial function. Materials and Methods: In 60 patients admitted to LTC unit for at least 1 year at moderate or high care load, demographic and clinical variables were taken. Blood samples were collected for the evaluations of oxidants/antioxidants, as thiobarbituric acid reactive substances, 8-hydroxy-2-deoxyguanosine, 8-isoprostanes, superoxide dismutase activity, glutathione, and vitamin D. In vitro, human umbilical vascular endothelial cells (HUVEC) were used to examine the effects of plasma on viability, ROS release and mitochondrial membrane potential. Results: The results obtained showed that the redox state of the elderly was quite balanced; mitochondrial membrane potential of HUVEC was reduced by about 20%, only. Also, the correlation analysis evidenced the association between mitochondrial function and the patients' outcomes. Interestingly, lower levels of mitochondrial membrane potential were found in the elderly who had symptoms suggestive of COVID-19 or with a confirmed diagnosis of COVID-19. Conclusion: The results of this study highlight the importance of mitochondrial function in the tendency to get a flu-like syndrome like COVID-19 in the elderly admitted to LTC unit. This information could have clinical implications for the management of old population.

Multitalented Synthetic Antimicrobial Peptides and Their Antibacterial, Antifungal and Antiviral Mechanisms

Despite the great strides in healthcare during the last century, some challenges still remained unanswered. The development of multi-drug resistant bacteria, the alarming growth of fungal infections, the emerging/re-emerging of viral diseases are yet a worldwide threat. Since the discovery of natural antimicrobial peptides able to broadly hit several pathogens, peptide-based therapeutics have been under the lenses of the researchers. This review aims to focus on synthetic peptides and elucidate their multifaceted mechanisms of action as antiviral, antibacterial and antifungal agents. Antimicrobial peptides generally affect highly preserved structures, e.g., the phospholipid membrane via pore formation or other constitutive targets like peptidoglycans in Gram-negative and Gram-positive bacteria, and glucan in the fungal cell wall. Additionally, some peptides are particularly active on biofilm destabilizing the microbial communities. They can also act intracellularly, e.g., on protein biosynthesis or DNA replication. Their intracellular properties are extended upon viral infection since peptides can influence several steps along the virus life cycle starting from viral receptor-cell interaction to the budding. Besides their mode of action, improvements in manufacturing to increase their half-life and performances are also taken into consideration together with advantages and impairments in the clinical usage. Thus far, the progress of new synthetic peptide-based approaches is making them a promising tool to counteract emerging infections.

Retrospective Study of Outcomes and Hospitalization Rates of Patients in Italy with a Confirmed Diagnosis of Early COVID-19 and Treated at Home Within 3 Days or After 3 Days of Symptom Onset with Prescribed and Non-Prescribed Treatments Between November 2020 and August 2021

BACKGROUND This retrospective study aimed to investigate outcomes and hospitalization rates in patients with a confirmed diagnosis of early COVID-19 treated at home with prescribed and non-prescribed treatments. MATERIAL AND METHODS The medical records of a cohort of 158 Italian patients with early COVID-19 treated at home were analyzed. Treatments consisted of indomethacin, low-dose aspirin, omeprazole, and a flavonoid-based food supplement, plus azithromycin, low-molecular-weight heparin, and betamethasone as needed. The association of treatment timeliness and of clinical variables with the duration of symptoms and with the risk of hospitalization was evaluated by logistic regression. RESULTS Patients were divided into 2 groups: group 1 (n=85) was treated at the earliest possible time (<72 h from onset of symptoms), and group 2 (n=73) was treated >72 h after the onset of symptoms. Clinical severity at the beginning of treatment was similar in the 2 groups. In group 1, symptom duration was shorter than in group 2 (median 6.0 days vs 13.0 days, P<0.001) and no hospitalizations occurred, compared with 19.18% hospitalizations in group 2. One patient in group 1 developed chest X-ray alterations and 2 patients experienced an increase in D-dimer levels, compared with 30 and 22 patients, respectively, in group 2. The main factor determining the duration of symptoms and the risk of hospitalization was the delay in starting therapy (P<0.001). CONCLUSIONS This real-world study of patients in the community showed that early diagnosis and early supportive patient management reduced the severity of COVID-19 and reduced the rate of hospitalization.