Flaviviridae Viruses and Oxidative Stress: Implications for Viral Pathogenesis

Neurological manifestations of Flaviviridae, Togaviridae, and Peribunyaviridae as vector-borne viruses

Vector-borne viruses pose a significant health problem worldwide, as they are transmitted to humans through the bite of infected arthropods such as mosquitoes and ticks. In recent years, emerging and re-emerging vector-borne diseases have gained attention as they can cause a wide spectrum of neurological manifestations. The neurological manifestations of vector-borne viruses encompass a board spectrum of clinical manifestations, ranging from mild and self-limiting symptoms to severe and life-threatening conditions. Common neurological complications include viral encephalitis, acute flaccid paralysis, aseptic meningitis, and various neuromuscular disorders. The specific viruses responsible for these neurological sequelae vary by geographic region and include Orthoflavivirus nilense, Zika virus, dengue virus, chikungunya virus, Japanese encephalitis virus, and tick-borne encephalitis virus. This review focuses on the pathogenesis of these neurologic complications and highlights the mechanisms by which vector-borne viruses invade the central nervous system and trigger neuroinflammatory responses. Diagnostic challenges and strategies for early detection of neurological manifestations are discussed, emphasising the importance of clinical suspicion and advanced laboratory testing.

Newcastle disease virus regulates its replication by instigating oxidative stress-driven Sirtuin 7 production

Reactive oxygen species (ROS) accumulation inside the cells instigates oxidative stress, activating stress-responsive genes. The viral strategies for promoting stressful conditions and utilizing the induced host proteins to enhance their replication remain elusive. The present work investigates the impact of oxidative stress responses on Newcastle disease virus (NDV) pathogenesis. Here, we show that the progression of NDV infection varies with intracellular ROS levels. Additionally, the results demonstrate that NDV infection modulates the expression of oxidative stress-responsive genes, majorly sirtuin 7 (SIRT7), a NAD+-dependent deacetylase. The modulation of SIRT7 protein, both through overexpression and knockdown, significantly impacts the replication dynamics of NDV in DF-1 cells. The activation of SIRT7 is found to be associated with the positive regulation of cellular protein deacetylation. Lastly, the results suggested that NDV-driven SIRT7 alters NAD+ metabolism in vitro and in ovo. We concluded that the elevated expression of NDV-mediated SIRT7 protein with enhanced activity metabolizes the NAD+ to deacetylase the host proteins, thus contributing to high virus replication.

Virus-induced brain pathology and the neuroinflammation-inflammation continuum: the neurochemists view

Fascinatingly, an abundance of recent studies has subscribed to the importance of cytotoxic immune mechanisms that appear to increase the risk/trigger for many progressive neurodegenerative disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis, and multiple sclerosis. Events associated with the neuroinflammatory cascades, such as ageing, immunologic dysfunction, and eventually disruption of the blood-brain barrier and the "cytokine storm", appear to be orchestrated mainly through the activation of microglial cells and communication with the neurons. The inflammatory processes prompt cellular protein dyshomeostasis. Parkinson's and Alzheimer's disease share a common feature marked by characteristic pathological hallmarks of abnormal neuronal protein accumulation. These Lewy bodies contain misfolded α-synuclein aggregates in PD or in the case of AD, they are Aβ deposits and tau-containing neurofibrillary tangles. Subsequently, these abnormal protein aggregates further elicit neurotoxic processes and events which contribute to the onset of neurodegeneration and to its progression including aggravation of neuroinflammation. However, there is a caveat for exclusively linking neuroinflammation with neurodegeneration, since it's highly unlikely that immune dysregulation is the only factor that contributes to the manifestation of many of these neurodegenerative disorders. It is unquestionably a complex interaction with other factors such as genetics, age, and environment. This endorses the "multiple hit hypothesis". Consequently, if the host has a genetic susceptibility coupled to an age-related weakened immune system, this makes them more susceptible to the virus/bacteria-related infection. This may trigger the onset of chronic cytotoxic neuroinflammatory processes leading to protein dyshomeostasis and accumulation, and finally, these events lead to neuronal destruction. Here, we differentiate "neuroinflammation" and "inflammation" with regard to the involvement of the blood-brain barrier, which seems to be intact in the case of neuroinflammation but defect in the case of inflammation. There is a neuroinflammation-inflammation continuum with regard to virus-induced brain affection. Therefore, we propose a staging of this process, which might be further developed by adding blood- and CSF parameters, their stage-dependent composition and stage-dependent severeness grade. If so, this might be suitable to optimise therapeutic strategies to fight brain neuroinflammation in its beginning and avoid inflammation at all.

Novel antioxidant protein target therapy to counter the prevalence and severity of SARS-CoV-2

Background

This review analyzed the magnitude of the COVID-19 pandemic globally and in India and the measures to counter its effect using natural and innate immune booster molecules. The study focuses on two phases: the first focuses on the magnitude, and the second on the effect of antioxidants (natural compounds) on SARS-CoV-2.

Methods

The magnitude of the prevalence, mortality, and comorbidities was acquired from the World Health Organization (WHO) report, media, a report from the Ministry of Health and Family Welfare (MoHFW), newspapers, and the National Centre of Disease Control (NCDC). Research articles from PubMed as well as other sites/journals and databases were accessed to gather literature on the effect of antioxidants.

Results

In the elderly and any chronic diseases, the declined level of antioxidant molecules enhanced the reactive oxygen species, which in turn deprived the immune system.

Conclusion

Innate antioxidant proteins like sirtuin and sestrin play a vital role in enhancing immunity. Herbal products and holistic approaches can also be alternative solutions for everyday life to boost the immune system by improving the redox balance in COVID-19 attack. This review analyzed the counteractive effect of alternative therapy to boost the immune system against the magnitude of the COVID-19 pandemic.

Zika virus infection induces expression of NRF2 and antioxidant systems in trophoblast cells

The nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor that plays a critical role in the xenobiotic and stress responses. During viral infection, NRF2 can modulate the host metabolism and innate immunity; however, the most common activity of NRF2 in viral diseases is controlling reactive oxygen species (ROS). The Zika virus (ZIKV) is involved in a vertical infection in pregnancy, with reported fetal health consequences. However, the possibility that ZIKV regulates NRF2 expression in placental trophoblasts has not been investigated. In this report, we evaluated the upregulation of NRF2 and antioxidant enzymes in a trophoblast-like cell. These findings could help us understand the antioxidant mechanism underlying the ZIKV infection in the placenta during pregnancy.

Virus infection participates in the occurrence and development of human diseases through monoamine oxidase

Monoamine oxidase (MAO) is a membrane-bound mitochondrial enzyme that maintains the steady state of neurotransmitters and other biogenic amines in biological systems through catalytic oxidation and deamination. MAO dysfunction is closely related to human neurological and psychiatric diseases and cancers. However, little is known about the relationship between MAO and viral infections in humans. This review summarises current research on how viral infections participate in the occurrence and development of human diseases through MAO. The viruses discussed in this review include hepatitis C virus, dengue virus, severe acute respiratory syndrome coronavirus 2, human immunodeficiency virus, Japanese encephalitis virus, Epstein-Barr virus, and human papillomavirus. This review also describes the effects of MAO inhibitors such as phenelzine, clorgyline, selegiline, M-30, and isatin on viral infectious diseases. This information will not only help us to better understand the role of MAO in the pathogenesis of viruses but will also provide new insights into the treatment and diagnosis of these viral diseases.

The Early Secretory Pathway Is Crucial for Multiple Aspects of the Hepatitis C Virus Life Cycle

Although most of the early events of the hepatitis C virus (HCV) life cycle are well characterized, our understanding of HCV egress is still unclear. Some reports implicate the conventional endoplasmic reticulum (ER)-Golgi route, while some propose noncanonical secretory routes. Initially, the envelopment of HCV nucleocapsid occurs by budding into the ER lumen. Subsequently, the HCV particle exit from the ER is assumed to be mediated by coat protein complex II (COPII) vesicles. COPII vesicle biogenesis also involves the recruitment of cargo to the site of vesicle biogenesis via interaction with COPII inner coat proteins. We investigated the modulation and the specific role of the individual components of the early secretory pathway in HCV egress. We observed that HCV inhibits cellular protein secretion and triggers the reorganization of the ER exit sites and ER-Golgi intermediate compartments (ERGIC). Gene-specific knockdown of the components of this pathway such as SEC16A, TFG, ERGIC-53, and COPII coat proteins demonstrated the functional significance of these components and the distinct role played by these proteins in various aspects of the HCV life cycle. SEC16A is essential for multiple steps in the HCV life cycle, whereas TFG is specifically involved in HCV egress and ERGIC-53 is crucial for HCV entry. Overall, our study establishes that the components of the early secretory pathway are essential for HCV propagation and emphasize the importance of the ER-Golgi secretory route in this process. Surprisingly, these components are also required for the early stages of the HCV life cycle due to their role in overall intracellular trafficking and homeostasis of the cellular endomembrane system. IMPORTANCE The virus life cycle involves entry into the host, replication of the genome, assembly of infectious progeny, and their subsequent release. Different aspects of the HCV life cycle, including entry, genome replication, and assembly, are well characterized; however, our understanding of the HCV release is still not clear and subject to debate due to varied findings. Here, we attempted to address this controversy and enhance our understanding of HCV egress by evaluating the role of the different components of the early secretory pathway in the HCV life cycle. To our surprise, we found that the components of the early secretory pathway are not only essential for HCV release but also contribute to many other earlier events of the HCV life cycle. This study emphasizes the importance of the early secretory pathway for the establishment of productive HCV infection in hepatocytes.

CMPK2 restricts Zika virus replication by inhibiting viral translation

Flaviviruses continue to emerge as global health threats. There are currently no Food and Drug Administration (FDA) approved antiviral treatments for flaviviral infections. Therefore, there is a pressing need to identify host and viral factors that can be targeted for effective therapeutic intervention. Type I interferon (IFN-I) production in response to microbial products is one of the host's first line of defense against invading pathogens. Cytidine/uridine monophosphate kinase 2 (CMPK2) is a type I interferon-stimulated gene (ISG) that exerts antiviral effects. However, the molecular mechanism by which CMPK2 inhibits viral replication is unclear. Here, we report that CMPK2 expression restricts Zika virus (ZIKV) replication by specifically inhibiting viral translation and that IFN-I- induced CMPK2 contributes significantly to the overall antiviral response against ZIKV. We demonstrate that expression of CMPK2 results in a significant decrease in the replication of other pathogenic flaviviruses including dengue virus (DENV-2), Kunjin virus (KUNV) and yellow fever virus (YFV). Importantly, we determine that the N-terminal domain (NTD) of CMPK2, which lacks kinase activity, is sufficient to restrict viral translation. Thus, its kinase function is not required for CMPK2's antiviral activity. Furthermore, we identify seven conserved cysteine residues within the NTD as critical for CMPK2 antiviral activity. Thus, these residues may form an unknown functional site in the NTD of CMPK2 contributing to its antiviral function. Finally, we show that mitochondrial localization of CMPK2 is required for its antiviral effects. Given its broad antiviral activity against flaviviruses, CMPK2 is a promising potential pan-flavivirus inhibitor.

Glutamine-Driven Metabolic Adaptation to COVID-19 Infection

Background

COVID-19 is known to be transmitted by direct contact, droplets or feces/orally. There are many factors which determines the clinical progression of the disease. Aminoacid disturbance in viral disease is shown in many studies. İn this study we aimed to evaluate the change of aminoacid metabolism especially the aspartate, glutamine and glycine levels which have been associated with an immune defence effect in viral disease.

Methods

Blood samples from 35 volunteer patients with COVID-19, concretized diagnosis was made by oropharyngeal from nazofaringeal swab specimens and reverse transcriptase-polymerase chain reaction, and 35 control group were analyzed. The amino acid levels were measured with liquid chromatography-mass spectrometry technology. Two groups were compared by Kolmogorov-Smirnov analysis, Kruskal-Wallis and the Mann-Whitney U. The square test was used to evaluate the tests obtained by counting, and the error level was taken as 0.05.

Results

The average age of the patient and control group were 48.5 ± 14.9 and 48.8 ± 14.6 years respectively. The decrease in aspartate (p = 5.5 × 10^-9) and glutamine levels (p = 9.0 × 10^-17) were significiantly in COVID group, whereas Glycine (p = 0.243) increase was not significiant.

Conclusions

Metabolic pathways, are affected in rapidly dividing cells in viral diseases which are important for immun defence. We determined that aspartate, glutamine and glycine levels in Covid 19 patients were affected by the warburg effect, malate aspartate shuttle, glutaminolysis and pentose phosphate pathway. Enteral or parenteral administration of these plasma amino acid levels will correct the duration and pathophysiology of the patients' stay in hospital and intensive care.

Antioxidant, Anti-inflammatory, and Immunomodulatory Roles of Nonvitamin Antioxidants in Anti-SARS-CoV-2 Therapy

Viral pathologies encompass activation of pro-oxidative pathways and inflammatory burst. Alleviating overproduction of reactive oxygen species and cytokine storm in COVID-19 is essential to counteract the immunogenic damage in endothelium and alveolar membranes. Antioxidants alleviate oxidative stress, cytokine storm, hyperinflammation, and diminish the risk of organ failure. Direct antiviral roles imply: impact on viral spike protein, interference with the ACE2 receptor, inhibition of dipeptidyl peptidase 4, transmembrane protease serine 2 or furin, and impact on of helicase, papain-like protease, 3-chyomotrypsin like protease, and RNA-dependent RNA polymerase. Prooxidative environment favors conformational changes in the receptor binding domain, promoting the affinity of the spike protein for the host receptor. Viral pathologies imply a vicious cycle, oxidative stress promoting inflammatory responses, and vice versa. The same was noticed with respect to the relationship antioxidant impairment-viral replication. Timing, dosage, pro-oxidative activities, mutual influences, and interference with other antioxidants should be carefully regarded. Deficiency is linked to illness severity.

Enterovirus A71 utilizes host cell lipid β-oxidation to promote its replication

Enterovirus A71 (EV-A71) is a major pathogen that causes severe and fatal cases of hand-foot-and-mouth disease (HFMD), which is an infectious disease that endangers children’s health. However, the pathogenic mechanisms underlying these severe clinical and pathological features remain incompletely understood. Metabolism and stress are known to play critical roles in multiple stages of the replication of viruses. Lipid metabolism and ER stress is an important characterization post viral infection. EV-A71 infection alters the perturbations of intracellular lipid homeostasis and induces ER stress. The characterizations induced by viral infections are essential for optimal virus replication and may be potential antiviral targets. In this study, we found that the addition of the chemical drug of ER stress, PKR IN, an inhibitor, or Tunicamycin, an activator, could significantly reduce viral replication with the decrease of lipid. The replication of viruses was reduced by Chemical reagent TOFA, an inhibitor of acetyl-CoA carboxylase (ACC) or C75, an inhibitor of fatty acid synthase (FASN), while enhanced by oleic acid (OA), which is a kind of exogenous supplement of triacylglycerol. The pharmacochemical reagent of carnitine palmitoyltransferase 1 (CPT1) called Etomoxir could knock down CPT1 to induce EV-A71 replication to decrease. This suggests that lipid, rather than ER stress, is the main factor affecting EV-A71 replication. In conclusion, this study revealed that it is the β-oxidation of lipid that plays a core role, not ER stress, which is only a concomitant change without restrictive effect, on virus replication.

Development and Characterization of a Genetically Stable Infectious Clone for a Genotype I Isolate of Dengue Virus Serotype 1

Dengue virus (DENV) is primarily transmitted by the bite of an infected mosquito of Aedes aegypti and Aedes albopictus, and symptoms caused may range from mild dengue fever to severe dengue hemorrhagic fever and dengue shock syndrome. Reverse genetic system represents a valuable tool for the study of DENV virology, infection, pathogenesis, etc. Here, we generated and characterized an eukaryotic-activated full-length infectious cDNA clone for a DENV serotype 1 (DENV-1) isolate, D19044, collected in 2019. Initially, nearly the full genome was determined by sequencing overlapping RT-PCR products, and was classified to be genotype I DENV-1. D19044 wild-type cDNA clone (D19044_WT) was assembled by four subgenomic fragments, in a specific order, into a low-copy vector downstream the CMV promoter. D19044_WT released the infectious virus at a low level (1.26 × 10³ focus forming units per milliliter [FFU/mL]) following plasmid transfection of BHK-21 cells. Further adaptation by consecutive virus passages up to passage 37, and seven amino acid substitutions (7M) were identified from passage-recovered viruses. The addition of 7M (D19044_7M) greatly improved viral titer (7.5 × 10⁴ FFU/mL) in transfected BHK-21 culture, and virus infections in 293T, Huh7.5.1, and C6/36 cells were also efficient. D19044_7M plasmid was genetically stable in transformant bacteria after five transformation-purification cycles, which did not change the capacity of producing infectious virus. Moreover, the D19044_7M virus was inhibited by mycophenolic acid in a dose-dependent manner. In conclusion, we have developed a DNA-launched full-length infectious clone for a genotype I isolate of DENV-1, with genetic stability in transformant bacteria, thus providing a useful tool for the study of DENV-1.

Can Biomarkers of Oxidative Stress in Serum Predict Disease Severity in West Nile Virus Infection? A Pilot Study

West Nile virus (WNV) can cause asymptomatic infection in humans, result in self-limiting febrile illness, or lead to severe West Nile Neuroinvasive disease (WNND). We conducted a pilot study to compare selected biomarkers of oxidative stress in sera of viremic West Nile virus patients and asymptomatic infected blood donors to investigate their potential as predictors of disease severity. We found that total oxidant status was elevated in WNND and in uncomplicated WNV infections (median 9.05 (IQR 8.37 to 9.74) and 7.14 (7.03 to 7.25) µmol H2O2 equiv./L, respectively) compared to asymptomatic infections (0.11 (0.07 to 0.19) µmol H2O2 equiv./L) (p = 0.048). MDA levels showed a similar trend to TOS, but differences were not significant at α = 0.05. Total antioxidant status did not differ significantly between different disease severity groups. Oxidative stress appears to be associated with more severe disease in WNV-infected patients. Our preliminary findings warrant prospective studies to investigate the correlation of oxidative stress with clinical outcomes and severity of WNV infection.

Redox Imbalance and Its Metabolic Consequences in Tick-Borne Diseases

One of the growing global health problems are vector-borne diseases, including tick-borne diseases. The most common tick-borne diseases include Lyme disease, tick-borne encephalitis, human granulocytic anaplasmosis, and babesiosis. Taking into account the metabolic effects in the patient’s body, tick-borne diseases are a significant problem from an epidemiological and clinical point of view. Inflammation and oxidative stress are key elements in the pathogenesis of infectious diseases, including tick-borne diseases. In consequence, this leads to oxidative modifications of the structure and function of phospholipids and proteins and results in qualitative and quantitative changes at the level of lipid mediators arising in both reactive oxygen species (ROS) and ROS enzyme–dependent reactions. These types of metabolic modifications affect the functioning of the cells and the host organism. Therefore, links between the severity of the disease state and redox imbalance and the level of phospholipid metabolites are being searched, hoping to find unambiguous diagnostic biomarkers. Assessment of molecular effects of oxidative stress may also enable the monitoring of the disease process and treatment efficacy.

Recombinant Muscovy Duck Parvovirus Led to Ileac Damage in Muscovy Ducklings

Waterfowl parvovirus (WPFs) has multiple effects on the intestinal tract, but the effects of recombinant Muscovy duck parvovirus (rMDPV) have not been elucidated. In this study, 48 one-day-old Muscovy ducklings were divided into an infected group and a control group. Plasma and ileal samples were collected from both groups at 2, 4, 6, and 8 days post-infection (dpi), both six ducklings at a time. Next, we analyzed the genomic sequence of the rMDPV strain. Results showed that the ileal villus structure was destroyed seriously at 4, 6, 8 dpi, and the expression of ZO-1, Occludin, and Claudin-1 decreased at 4, 6 dpi; 4, 6, 8 dpi; and 2, 6 dpi, respectively. Intestinal cytokines IFN-α, IL-1β and IL-6 increased at 6 dpi; 8 dpi; and 6, 8 dpi, respectively, whereas IL-2 decreased at 6, 8 dpi. The diversity of ileal flora increased significantly at 4 dpi and decreased at 8 dpi. The bacteria Ochrobactrum and Enterococcus increased and decreased at 4, 8 dpi; 2, 4 dpi, respectively. Plasma MDA increased at 2 dpi, SOD, CAT, and T-AOC decreased at 2, 4, 8 dpi; 4, 8 dpi; and 4, 6, 8 dpi, respectively. These results suggest that rMDPV infection led to early intestinal barrier dysfunction, inflammation, ileac microbiota disruption, and oxidative stress.

Dual-Role Ubiquitination Regulation Shuttling the Entire Life Cycle of the Flaviviridae

Ubiquitination is a reversible protein post-translational modification that regulates various pivotal physiological and pathological processes in all eukaryotes. Recently, the antiviral immune response is enhanced by the regulation of ubiquitination. Intriguingly, Flaviviridae viruses can ingeniously hijack the ubiquitination system to help them survive, which has become a hot topic among worldwide researchers. The Flaviviridae family members, such as HCV and CSFV, can cause serious diseases of humans and animals around the world. The multiple roles of ubiquitination involved in the life cycle of Flaviviridae family would open new sight for future development of antiviral tactic. Here, we discuss recent advances with regard to functional roles of ubiquitination and some ubiquitin-like modifications in the life cycle of Flaviviridae infection, shedding new light on the antiviral mechanism research and therapeutic drug development.

Five nanometer size highly positive silver nanoparticles are bactericidal targeting cell wall and adherent fimbriae expression

To tackle growing antibiotic resistance (AR) and hospital-acquired infections (HAIs), novel antimicrobials are warranted that are effective against HAIs and safer for human use. We hypothesize that small 5 nm size positively charged nanoparticles could specifically target bacterial cell wall and adherent fimbriae expression, serving as the next generation antibacterial agent. Herein we show highly positively charged, 5 nm amino-functionalized silver nanoparticles (NH₂–AgNPs) were bactericidal; highly negatively charged, 45 nm citrate-functionalized AgNPs (Citrate–AgNPs) were nontoxic; and Ag⁺ ions were bacteriostatic forming honeycomb-like potentially resistant phenotype, at 10 µg Ag/mL in E. coli. Further, adherent fimbriae were expressed with Citrate–AgNPs (0.5–10 µg/mL), whereas NH₂–AgNPs (0.5–10 µg/mL) or Ag⁺ ions (only at 10 µg/mL) inhibited fimbriae expression. Our results also showed no lipid peroxidation in human lung epithelial and dermal fibroblast cells upon NH₂–AgNPs treatments, suggesting NH₂–AgNPs as a biocompatible antibacterial candidate. Potent bactericidal effects demonstrated by biocompatible NH₂–AgNPs and the lack of toxicity of Citrate–AgNPs lend credence to the hypothesis that small size, positively charged AgNPs may serve as a next-generation antibacterial agent, potentially addressing the rising HAIs and patient health and safety.

Emerging therapies for glioblastoma: current state and future directions

Glioblastoma (GBM) is the most common high-grade primary malignant brain tumor with an extremely poor prognosis. Given the poor survival with currently approved treatments for GBM, new therapeutic strategies are urgently needed. Advances in decades of investment in basic science of glioblastoma are rapidly translated into innovative clinical trials, utilizing improved genetic and epigenetic profiling of glioblastoma as well as the brain microenvironment and immune system interactions. Following these encouraging findings, immunotherapy including immune checkpoint blockade, chimeric antigen receptor T (CAR T) cell therapy, oncolytic virotherapy, and vaccine therapy have offered new hope for improving GBM outcomes; ongoing studies are using combinatorial therapies with the aim of minimizing adverse side-effects and augmenting antitumor immune responses. In addition, techniques to overcome the blood-brain barrier (BBB) for targeted delivery are being tested in clinical trials in patients with recurrent GBM. Here, we set forth the rationales for these promising therapies in treating GBM, review the potential novel agents, the current status of preclinical and clinical trials, and discuss the challenges and future perspectives in glioblastoma immuno-oncology.

Evaluation of dyslipidemia in preeclamptic pregnant women and determination of the predictive value of the hemato-lipid profile: A prospective, cross-sectional, case-control study

Objective:

In this study, we examined the serum hematologic and lipid parameters of pregnant women with preeclampsia and an age- and gestational-age matched normotensive control group. We also compared the ratios of hemato-lipid parameters defined as systemic inflammatory markers and determined the predictive value of these values in preeclampsia.

Materials and Methods:

All patients diagnosed with late-onset preeclampsia or severe preeclampsia between 34 and 40 weeks of gestation at Inonu University Faculty of Medicine between March 2019 and October 2020 were included.

Results:

A total of 253 pregnant women were included in the study period. When the study groups were compared in terms of hematological and blood lipid profile; while serum lymphocyte, triglyceride, and total cholesterol levels were significantly higher in the preeclampsia group than in the control group (p<0.001, p<0.001, p=0.013, respectively); high-density lipoprotein (HDL)-cholesterol levels were found to be significantly lower (p=0.017). The cut-off value for the monocyte/HDL ratio in predicting severe preeclampsia was 16.65 with 59.0% sensitivity and 85.4% specificity [the area under the receiver operating characteristic 0.756, 95% confidence interval (CI) 0.681-0.821, p<0.001]. Multivariate analysis showed that the monocyte/HDL ratio was independently associated with both preeclampsia and severe preeclampsia [odds ratio (OR): 1.094; 95% CI 1.009-1.185 and OR: 1.731; 95% CI 1.218-2.459, respectively].

Conclusion:

This study demonstrated that serum triglyceride and total cholesterol levels were significantly higher and serum HDL-cholesterol levels were significantly lower in pregnant women with late-onset preeclampsia compared to normotensive pregnant women. Additionally, this study revealed that the measurement of monocyte/HDL ratio in the pregnant population could be a useful clinical tool for predicting preeclampsia.

Metabolic Response to Tick-Borne Encephalitis Virus Infection and Bacterial Co-Infections

Ticks are vectors of various pathogens, including tick-borne encephalitis virus and bacteria such as B. burgdorferi and A. phagocytophilum, causing infections/co-infections, which are still a diagnostic and therapeutic problem. Therefore, the aim of this study was to compare the effects of TBEV infection/bacterial co-infection on metabolic changes in the blood of patients before and after treatment. It was found that those infections promote plasma ROS enhanced generation and antioxidant defence reduction, especially in relation to glutathione and thioredoxin systems, despite the increased effectiveness of Nrf2 transcription factor in granulocytes. Observed oxidative stress promotes the oxidative modifications of phospholipids containing polyunsaturated fatty acids (LA, AA, EPA) with increased lipid peroxidation (estimated as 8-isoPGF2α, 4-HNE). It is accompanied by protein modifications measured as 4-HNE-protein adducts, carbonyl groups, dityrosine increase, and tryptophan level decrease, which promote structural and functional modification of the following transcription factors: Nrf2 and NFkB inhibitors. The lower level of 8-iso-PGF2α in co-infections indicates an impairment of the body’s ability to intensify inflammation and fight co-infections, while an increased level of Trx after therapy may contribute to the intensification of the inflammatory process. The obtained results indicate the potential possibility of using the assessed metabolic parameters to introduce targeted pharmacotherapy in cases of TBEV infections/bacterial co-infections.

COVID-19, Oxidative Stress, and Neuroinflammation in the Depression Route

COVID-19 is associated with oxidative stress, peripheral hyper inflammation, and neuroinflammation, especially in individuals with a more severe form of the disease. Some studies provide evidence on the onset or exacerbation of major depressive disorder (MDD), among other psychiatric disorders due to COVID-19. Oxidative stress and neuroinflammation are associated conditions, especially in the more severe form of MDD and in refractoriness to available therapeutic strategies. Inflammatory cytokines in the COVID-19 hyper inflammation process can activate the hypothalamic–pituitary–adrenal (HPA) axis and the indoleamine-2,3-dioxygenase (IDO) enzyme. IDO activation can reduce tryptophan and increase toxic metabolites of the kynurenine pathway, which increases glial activation, neuroinflammation, toxicity, and neuronal death. This review surveyed a number of studies and analyzed the mechanisms of oxidative stress, inflammation, and neuroinflammation involved in COVID-19 and depression. Finally, the importance of more protocols that can help elucidate the interaction between these mechanisms underlying COVID-19 and MDD and the possible therapeutic strategies involved in the interaction of these mechanisms are highlighted.

Dengue Virus Replication Is Associated with Catecholamine Biosynthesis and Metabolism in Hepatocytes

Previously, the association between the catecholamine biosynthetic enzyme L-Dopa decarboxylase (DDC) and Dengue virus (DV) replication was demonstrated in liver cells and was found to be mediated at least by the interaction between DDC and phosphoinositide 3-kinase (PI3K). Here, we show that biogenic amines production and uptake impede DV replication in hepatocytes and monocytes, while the virus reduces catecholamine biosynthesis, metabolism, and transport. To examine how catecholamine biosynthesis/metabolism influences DV, first, we verified the role of DDC by altering DDC expression. DDC silencing enhanced virus replication, but not translation, attenuated the negative effect of DDC substrates on the virus and reduced the infection related cell death. Then, the role of the downstream steps of the catecholamine biosynthesis/metabolism was analyzed by chemical inhibition of the respective enzymes, application of their substrates and/or their products; moreover, reserpine, the inhibitor of the vesicular monoamine transporter 2 (VMAT2), was used to examine the role of uptake/storage of catecholamines on DV. Apart from the role of each enzyme/transporter, these studies revealed that the dopamine uptake, and not the dopamine-signaling, is responsible for the negative effect on DV. Accordingly, all treatments expected to enhance the accumulation of catecholamines in the cell cytosol suppressed DV replication. This was verified by the use of chemical inducers of catecholamine biosynthesis. Last, the cellular redox alterations due to catecholamine oxidation were not related with the inhibition of DV replication. In turn, DV apart from its negative impact on DDC, inhibits tyrosine hydroxylase, dopamine beta-hydroxylase, monoamine oxidase, and VMAT2 expression.

Antiviral Effect of Selenomethionine on Porcine Deltacoronavirus in Pig Kidney Epithelial Cells

Porcine deltacoronavirus (PDCoV) is an emerging porcine intestinal coronavirus in recent years, which mainly causes different degrees of vomiting and diarrhea in piglets and has caused great harm to the swine husbandry worldwide since its report. Selenium is an essential trace element for organisms and has been demonstrated to have antiviral effects. In this study, pig kidney epithelial (LLC-PK) cells were used to study the antiviral activity of selenomethionine (Se-Met) (2, 4, 8, and 16 μM) against PDCoV by detecting the replication of the virus, the expression of the mitochondrial antiviral signal protein (MAVS) protein, and the phosphorylation of interferon regulatory factor-3 (IRF-3), IFN-α, and IFN-β, and the changes in glutathione content, glutathione peroxidase, superoxide dismutase activity, and hydrogen peroxide content in the cells. The results showed that Se-Met at higher than physiological concentrations (16 μM) could significantly inhibit the replication of PDCoV in LLC-PK cells and enhance the expression of MAVS protein and the phosphorylation of IRF-3. In addition, Se-Met also improved the intracellular production of IFNα/β and antioxidant capacity with increasing doses. These data suggest that the availability of selenium through selenomethionine supports the antiviral response in porcine kidney cells, and the specific mechanism is attributed to the improved cellular antioxidant capacity and activation of the MAVS pathway by Se-Met.

Preclinical efficacy and safety of novel SNAT against SARS-CoV-2 using a hamster model

To address the unprecedented global public health crisis due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we designed and developed a novel antiviral nano-drug, called SNAT (Smart Nano-Enabled Antiviral Therapeutic), comprised of taxoid (Tx)-decorated amino (NH₂)-functionalized near-atomic size positively charged silver nanoparticles (Tx-[NH₂-AgNPs]) that are stable for over 3 years. Using a hamster model, we tested the preclinical efficacy of inhaled SNAT on the body weight, virus titer, and histopathology of lungs in SARS-CoV-2-infected hamsters, including biocompatibility in human lung epithelium and dermal fibroblasts using lactase dehydrogenase (LDH) and malondialdehyde (MDA) assays. Our results showed SNAT could effectively reverse the body weight loss, reduce the virus load in oral swabs, and improve lung health in hamsters. Furthermore, LDH assay showed SNAT is noncytotoxic, and MDA assay demonstrated SNAT to be an antioxidant, potentially quenching lipid peroxidation, in both the human cells. Overall, these promising pilot preclinical findings suggest SNAT as a novel, safer antiviral drug lead against SARS-CoV-2 infection and may find applications as a platform technology against other respiratory viruses of epidemic and pandemic potential.

In human astrocytes neurotropic flaviviruses increase autophagy, yet their replication is autophagy-independent

Astrocytes, an abundant type of glial cells, are the key cells providing homeostasis in the central nervous system. Due to their susceptibility to infection, combined with high resilience to virus-induced cell death, astrocytes are now considered one of the principal types of cells, responsible for virus retention and dissemination within the brain. Autophagy plays an important role in elimination of intracellular components and in maintaining cellular homeostasis and is also intertwined with the life cycle of viruses. The physiological significance of autophagy in astrocytes, in connection with the life cycle and transmission of viruses, remains poorly investigated. In the present study, we investigated flavivirus-induced modulation of autophagy in human astrocytes by monitoring a tandem fluorescent-tagged LC3 probe (mRFP-EGFP-LC3) with confocal and super-resolution fluorescence microscopy. Astrocytes were infected with tick-borne encephalitis virus (TBEV) or West Nile virus (WNV), both pathogenic flaviviruses, and with mosquito-only flavivirus (MOF), which is considered non-pathogenic. The results revealed that human astrocytes are susceptible to infection with TBEV, WNV and to a much lower extent also to MOF. Infection and replication rates of TBEV and WNV are paralleled by increased rate of autophagy, whereas autophagosome maturation and the size of autophagic compartments are not affected. Modulation of autophagy by rapamycin and wortmannin does not influence TBEV and WNV replication rate, whereas bafilomycin A1 attenuates their replication and infectivity. In human astrocytes infected with MOF, the low infectivity and the lack of efficient replication of this flavivirus are mirrored by the absence of an autophagic response.

Nicotinamide Adenine Dinucleotide-Dependent Flavin Oxidoreductase of Mycoplasma hyopneumoniae Functions as a Potential Novel Virulence Factor and Not Only as a Metabolic Enzyme

Mycoplasma hyopneumoniae (Mhp) is the main pathogen that causes enzootic pneumonia, a disease that has a significant impact on the pig industry worldwide. The pathogenesis of enzootic pneumonia, especially possible virulence factors of Mhp, has still not been fully elucidated. The transcriptomic and proteomic analyses of different Mhp strains reported in the literature have revealed differences in virulence, and differences in RNA transcription levels between high- and low-virulence strains initially indicated that nicotinamide adenine dinucleotide (NADH)-dependent flavin oxidoreductase (NFOR) was related to Mhp pathogenicity. Prokaryotic expression and purification of the NFOR protein from Mhp were performed, a rabbit-derived polyclonal antibody against NFOR was prepared, and multiple sequence alignment and evolutionary analyses of Mhp NFOR were performed. For the first time, it was found that the NFOR protein was conserved among all Mhp strains, and NFOR was localized to the cell surface and could adhere to immortalized porcine bronchial epithelial cells (hTERT-PBECs). Adhesion to hTERT-PBECs could be specifically inhibited by an anti-NFOR polyclonal antibody, and the rates of adhesion to both high- and low-virulence strains, 168 and 168L, significantly decreased by more than 40%. Moreover, Mhp NFOR not only recognized and interacted with host fibronectin and plasminogen but also induced cellular oxidative stress and apoptosis in hTERT-PBECs. The release of lactate dehydrogenase by hTERT-PBECs incubated with Mhp NFOR was significantly positively correlated with the virulence of Mhp. Overall, in addition to being a metabolic enzyme related to oxidative stress, NFOR may also function as a potential novel virulence factor of Mhp, thus contributing to the pathogenesis of Mhp; these findings provide new ideas and theoretical support for studying the pathogenic mechanisms of other mycoplasmas.

Multisystem Inflammatory Syndrome in Children (MIS-C) Following SARS-CoV-2 Infection: Role of Oxidative Stress

With the appearance of the SARS-CoV-2 virus in December 2019, all countries in the world have implemented different strategies to prevent its spread and to intensively search for effective treatments. Initially, severe cases of the disease were considered in adult patients; however, cases of older school-age children and adolescents who presented fever, hypotension, severe abdominal pain and cardiac dysfunction, positive for SARS-CoV-2 infection, have been reported, with increased pro-inflammatory cytokines and tissue damage, condition denominated multisystemic inflammatory syndrome (MIS-C); The emerging data from patients with MIS-C have suggested unique characteristics in the immunological response and also clinical similarities with other inflammatory syndromes, which can support as a reference in the search for molecular mechanisms involved in MIS-C. We here in propose that oxidative stress (OE) may play a very important role in the pathophysiology of MIS-C, such as occurs in Kawasaki disease (KD), severe COVID-19 in adults and other processes with characteristics of vascular damage similar to MIS- C, for which we review the available information that can be correlated with possible redox mechanisms.

HCV Activates Somatic L1 Retrotransposition-A Potential Hepatocarcinogenesis Pathway

Hepatitis C virus (HCV) is a common cause of hepatocellular carcinoma (HCC). The activation and mutagenic consequences of L1 retrotransposons in virus-associated-HCC have been documented. However, the direct influence of HCV upon L1 elements is unclear, and is the focus of the present study. L1 transcript expression was evaluated in a publicly available liver tissue RNA-seq dataset from patients with chronic HCV hepatitis (CHC), as well as healthy controls. L1 transcript expression was significantly higher in CHC than in controls. L1orf1p (a L1 encoded protein) expression was observed in six out of 11 CHC livers by immunohistochemistry. To evaluate the influence of HCV on retrotransposition efficiency, in vitro engineered-L1 retrotransposition assays were employed in Huh7 cells in the presence and absence of an HCV replicon. An increased retrotransposition rate was observed in the presence of replicating HCV RNA, and persisted in cells after viral clearance due to sofosbuvir (PSI7977) treatment. Increased retrotransposition could be due to dysregulation of the DNA-damage repair response, including homologous recombination, due to HCV infection. Altogether these data suggest that L1 expression can be activated before oncogenic transformation in CHC patients, with HCV-upregulated retrotransposition potentially contributing to HCC genomic instability and a risk of transformation that persists post-viral clearance.

Oxidative stress specifically inhibits replication of dengue virus

Reactive oxygen species (ROS) are chemically active species which are involved in maintaining cellular and signalling processes at physiological concentrations. Therefore, cellular components that regulate redox balance are likely to play a crucial role in viral life-cycle either as promoters of viral replication or with antiviral functions. Zinc is an essential micronutrient associated with anti-oxidative systems and helps in maintaining a balanced cellular redox state. Here, we show that zinc chelation leads to induction of reactive oxygen species (ROS) in epithelial cells and addition of zinc restores ROS levels to basal state. Addition of ROS (H₂O₂) inhibited dengue virus (DENV) infection in a dose-dependent manner indicating that oxidative stress has adverse effects on DENV infection. ROS affects early stages of DENV replication as observed by quantitation of positive and negative strand viral RNA. We observed that addition of ROS specifically affected viral titres of positive strand RNA viruses. We further demonstrate that ROS specifically altered SEC31A expression at the ER suggesting a role for SEC31A-mediated pathways in the life-cycle of positive strand RNA viruses and provides an opportunity to identify drug targets regulating oxidative stress responses for antiviral development.

Porcine circovirus 2 manipulates PERK-ERO1α axis of endoplasmic reticulum in favor of its replication by derepressing viral DNA from HMGB1 sequestration within nuclei

Porcine circovirus type 2 (PCV2) causes several disease syndromes in grower pigs. PCV2 infection triggers endoplasmic reticulum (ER) stress, autophagy and oxidative stress, all of which support PCV2 replication. We have recently reported that nuclear HMGB1 is an anti-PCV2 factor by binding to viral genomic DNA. However, how PCV2 manipulates host cell responses to favor its replication has not been explored. Here, we demonstrate that PCV2 infection increased expression of ERO1α, generation of ROS and nucleocytoplasmic migration of HMGB1 via PERK activation in PK-15 cells. Inhibition of PERK or ERO1α repressed ROS production in PCV2-infected cells and increased HMGB1 retention within nuclei. These findings indicate that PCV2-induced activation of the PERK-ERO1α axis would lead to enhanced generation of ROS sufficient to decrease HMGB1 retention in the nuclei, thus derepressing viral DNA from HMGB1 sequestration. The viral Rep and Cap proteins were able to induce PERK-ERO1α-mediated ROS accumulation. Cysteine residues 107 and 305 of Rep or 108 of Cap played important roles in PCV2-induced PERK activation and distribution of HMGB1. Of the mutant viruses, only the mutant PCV2 with substitution of all three cysteine residues failed to activate PERK with reduced ROS generation and decreased nucleocytoplasmic migration of HMGB1. Collectively, this study offers novel insight into the mechanism of enhanced viral replication in which PCV2 manipulates ER to perturb its redox homeostasis via the PERK-ERO1α axis and the ER-sourced ROS from oxidative folding is sufficient to reduce HMGB1 retention in the nuclei, hence the release of HMGB1-bound viral DNA for replication. IMPORTANCE Considering the fact that clinical PCVAD mostly results from activation of latent PCV2 infection by confounding factors such as co-infection or environmental stresses, we propose that such confounding factors might impose oxidative stress to the animals where PCV2 in infected cells might utilize the elevated ROS to promote HMGB1 migration out of nuclei in favor of its replication. An animal infection model with a particular stressor could be approached with or without antioxidant treatment to examine the relationship among the stressor, ROS level, HMGB1 distribution in target tissues, virus replication and severity of PCVAD. This will help decide the use of antioxidants in the feeding regime on pig farms that suffer from PCVAD. Further investigation could examine if similar strategies are employed by DNA viruses, such as PCV3 and BFDV and if there is cross-talk among ER stress, autophagy/mitophagy and mitochondria-sourced ROS in favor of PCV2 replication.

A Comparison of Oxidative Stress Biomarkers in the Serum of Healthy Polish Dairy Goats with Those Naturally Infected with Small Ruminant Lentivirus in the Course of Lactation

The present study examines the effects of natural infection by small ruminant lentivirus (SRLV) in the two most common goat breeds in Poland, i.e., Polish white improved and polish fawn improved. It focuses on biomarkers of oxidative stress, oxidatively modified proteins and antioxidant defenses, ceruloplasmin level as an acute phase protein, and the activities of antioxidant enzymes in the goat serum. It was conducted on 24 goats divided into two equal groups: one SRLV-seropositive (SRLV-SP) and another SRLV-seronegative (SRLV-SN). Both groups were identical in terms of breed and parity. Despite infection, the SRLV-SP goats demonstrated no symptoms of caprine arthritis-encephalitis. In addition, the SRLV-SP goats did not reveal pronounced dysfunctions in oxidative stress biomarkers in the serum compared to the SRLV-SN animals. However, both groups demonstrated elevated levels of the aldehydic and ketonic derivatives of oxidatively modified proteins during the lactation period. In addition, both groups retained a high total antioxidant capacity in serum despite the decrease of enzyme antioxidant defenses throughout the 200-day lactation period.

The Protective Effect of Aspirin Eugenol Ester on Oxidative Stress to PC12 Cells Stimulated with H2O2 through Regulating PI3K/Akt Signal Pathway

Aspirin eugenol ester (AEE) is a new pharmaceutical compound esterified by aspirin and eugenol, which has anti-inflammatory, antioxidant, and other pharmacological activities. This study is aimed at identifying the protective effect of AEE against H₂O₂-induced apoptosis in rat adrenal pheochromocytoma PC12 cells and the possible mechanisms. The results of cell viability assay showed that AEE could increase the viability of PC12 cells stimulated by H₂O₂, while AEE alone had no significant effect on the viability of PC12 cells. Compared with the control group, the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were significantly decreased, and the content of malondialdehyde (MDA) was significantly increased in the H₂O₂ group. By AEE pretreatment, the level of MDA was reduced and the levels of SOD, CAT, and GSH-Px were increased in H₂O₂-stimulated PC12 cells. In addition, AEE could reduce the apoptosis of PC12 cells induced by H₂O₂ via reducing superoxide anion, intracellular ROS, and mitochondrial ROS (mtROS) and increasing the levels of mitochondrial membrane potential (ΔΨm). Furthermore, the results of western blotting showed that compared with the control group, the expression of p-PI3K, p-Akt, and Bcl-2 was significantly decreased, while the expression of Caspase-3 and Bax was significantly increased in the H₂O₂ group. In the AEE group, AEE pretreatment could upregulate the expression of p-PI3K, p-Akt, and Bcl-2 and downregulate the expression of Caspase-3 and Bax in PC12 cells stimulated with H₂O₂. The silencing of PI3K with shRNA and its inhibitor-LY294002 could abrogate the protective effect of AEE in PC12 cells. Therefore, AEE has a protective effect on H₂O₂-induced PC12 cells by regulating the PI3K/Akt signal pathway to inhibit oxidative stress.

Tandem Mass Tag-Based Quantitative Proteomic Analysis of Chicken Bursa of Fabricius Infected With Reticuloendotheliosis Virus

Reticuloendotheliosis virus (REV) is a type C avian retrovirus that causes immunosuppression, dwarf syndrome, and lymphoma in infected hosts. In this study, we used tandem mass tag (TMT) labeling and liquid chromatography–tandem mass spectrometry (LC-MS/MS) to characterize protein alterations in chicken bursa of Fabricius, before and after REV infection at 7, 14, 21, and 28 days. Our data showed that 1,127, 999, 910, and 1,138 differentially expressed proteins were significantly altered at 7, 14, 21, and 28 days after REV infection, respectively. Morphological analysis showed that REV infection reduced in cortical lymphocytes, bursal follicle atrophy, and nuclear damage. Bioinformatics analysis indicated these proteins were mainly involved with immune responses, energy metabolism, cellular processes, biological regulation, metabolic processes, response to stimuli, and multicellular organismal process. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway cluster analysis showed that post-infection, proteins were enriched in the cell cycle, Wnt signaling, antigen processing and presentation, cytokine receptor interaction, adenosine 3′,5′-cyclic monophosphate signaling pathway, and NF-κB signaling. In addition, we observed that peroxiredoxin 4 (PRDX4), peroxiredoxin 6 (PRDX6), glutathione peroxidase 3 (GPX3), catalase (CAT), and peroxidasin (PXDN) were involved in oxidative stress. Some heat shock protein (HSP) family members such as HSPH1, DNAJA4, HSPA8, and HSPA4L also changed significantly after REV infection. These findings help clarify interactions between REV and the host and provides mechanistic insights on REV-induced host immunosuppression.

ZIKV Disrupts Placental Ultrastructure and Drug Transporter Expression in Mice

Congenital Zika virus (ZIKV) infection can induce fetal brain abnormalities. Here, we investigated whether maternal ZIKV infection affects placental physiology and metabolic transport potential and impacts the fetal outcome, regardless of viral presence in the fetus at term. Low (103 PFU-ZIKVPE243; low ZIKV) and high (5x107 PFU-ZIKVPE243; high ZIKV) virus titers were injected into immunocompetent (ICompetent C57BL/6) and immunocompromised (ICompromised A129) mice at gestational day (GD) 12.5 for tissue collection at GD18.5 (term). High ZIKV elicited fetal death rates of 66% and 100%, whereas low ZIKV induced fetal death rates of 0% and 60% in C57BL/6 and A129 dams, respectively. All surviving fetuses exhibited intrauterine growth restriction (IUGR) and decreased placental efficiency. High-ZIKV infection in C57BL/6 and A129 mice resulted in virus detection in maternal spleens and placenta, but only A129 fetuses presented virus RNA in the brain. Nevertheless, pregnancies in both strains produced fetuses with decreased head sizes (p<0.05). Low-ZIKV-A129 dams had higher IL-6 and CXCL1 levels (p<0.05), and their placentas showed increased CCL-2 and CXCL-1 contents (p<0.05). In contrast, low-ZIKV-C57BL/6 dams had an elevated CCL2 serum level and increased type I and II IFN expression in the placenta. Notably, less abundant microvilli and mitochondrial degeneration were evidenced in the placental labyrinth zone (Lz) of ICompromised and high-ZIKV-ICompetent mice but not in low-ZIKV-C57BL/6 mice. In addition, decreased placental expression of the drug transporters P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) and the lipid transporter Abca1 was detected in all ZIKV-infected groups, but Bcrp and Abca1 were only reduced in ICompromised and high-ZIKV ICompetent mice. Our data indicate that gestational ZIKV infection triggers specific proinflammatory responses and affects placental turnover and transporter expression in a manner dependent on virus concentration and maternal immune status. Placental damage may impair proper fetal-maternal exchange function and fetal growth/survival, likely contributing to congenital Zika syndrome.

(E)-Guggulsterone Inhibits Dengue Virus Replication by Upregulating Antiviral Interferon Responses through the Induction of Heme Oxygenase-1 Expression

Dengue virus (DENV) infection, which causes dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, is a severe global health problem in tropical and subtropical areas. There is no effective vaccine or drug against DENV infection. Thus, the development of anti-DENV agents is imperative. This study aimed to assess the anti-DENV activity of (E)-guggulsterone using a DENV infectious system. A specific inhibitor targeting signal molecules was used to evaluate the molecular mechanisms of action. Western blotting and qRT-PCR were used to determine DENV protein expression and RNA replication, respectively. Finally, an ICR suckling mouse model was used to examine the anti-DENV activity of (E)-guggulsterone in vivo. A dose-dependent inhibitory effect of (E)-guggulsterone on DENV protein synthesis and RNA replication without cytotoxicity was observed. The mechanistic studied revealed that (E)-guggulsterone stimulates Nrf2-mediated heme oxygenase-1 (HO-1) expression, which increases the antiviral interferon responses and downstream antiviral gene expression by blocking DENV NS2B/3B protease activity. Moreover, (E)-guggulsterone protected ICR suckling mice from life-threatening DENV infection. These results suggest that (E)-guggulsterone can be a potential supplement for controlling DENV replication.

Impact of Zinc, Glutathione, and Polyphenols as Antioxidants in the Immune Response against SARS-CoV-2

SARS-CoV-2, the coronavirus triggering the disease COVID-19, has a catastrophic health and socioeconomic impact at a global scale. Three key factors contribute to the pathogenesis of COVID-19: excessive inflammation, immune system depression/inhibition, and a set of proinflammatory cytokines. Common to these factors, a central function of oxidative stress has been highlighted. A diversity of clinical trials focused predominantly on antioxidants are being implemented as potential therapies for COVID-19. In this study, we look at the role of zinc, glutathione, and polyphenols, as key antioxidants of possible medicinal or nutritional significance, and examine their role in the antiviral immune response induced by SARS-Cov-2. An unresolved question is why some people experience chronic COVID and others do not. Understanding the relationship between SARS-CoV-2 and the immune system, as well as the role of defective immune responses to disease development, would be essential to recognize the pathogenesis of COVID-19, the risk factors that affect the harmful consequences of the disease, and the rational design of successful therapies and vaccinations. We expect that our research will provide a novel perspective that contributes to the design of clinical or nutritional targets for the prevention of this pandemic.

The Role of Bcl-xL Protein in Viral Infections

Bcl-xL represents a family of proteins responsible for the regulation of the intrinsic apoptosis pathway. Due to its anti-apoptotic activity, Bcl-xL co-determines the viability of various virally infected cells. Their survival may determine the effectiveness of viral replication and spread, dynamics of systemic infection, and viral pathogenesis. In this paper, we have reviewed the role of Bcl-xL in the context of host infection by eight different RNA and DNA viruses: hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), influenza A virus (IAV), Epstein-Barr virus (EBV), human T-lymphotropic virus type-1 (HTLV-1), Maraba virus (MRBV), Schmallenberg virus (SBV) and coronavirus (CoV). We have described an influence of viral infection on the intracellular level of Bcl-xL and discussed the impact of Bcl-xL-dependent cell survival control on infection-accompanying pathogenic events such as tissue damage or oncogenesis. We have also presented anti-viral treatment strategies based on the pharmacological regulation of Bcl-xL expression or activity.

Host cell glutamine metabolism as a potential antiviral target

A virus minimally contains a nucleic acid genome packaged by a protein coat. The genome and capsid together are known as the nucleocapsid, which has an envelope containing a lipid bilayer (mainly phospholipids) originating from host cell membranes. The viral envelope has transmembrane proteins that are usually glycoproteins. The proteins in the envelope bind to host cell receptors, promoting membrane fusion and viral entry into the cell. Virus-infected host cells exhibit marked increases in glutamine utilization and metabolism. Glutamine metabolism generates ATP and precursors for the synthesis of macromolecules to assemble progeny viruses. Some compounds derived from glutamine are used in the synthesis of purines and pyrimidines. These latter compounds are precursors for the synthesis of nucleotides. Inhibitors of glutamine transport and metabolism are potential candidate antiviral drugs. Glutamine is also an essential nutrient for the functions of leukocytes (lymphocyte, macrophage, and neutrophil), including those in virus-infected patients. The increased glutamine requirement for immune cell functions occurs concomitantly with the high glutamine utilization by host cells in virus-infected patients. The development of antiviral drugs that target glutamine metabolism must then be specifically directed at virus-infected host cells to avoid negative effects on immune functions. Therefore, the aim of this review was to describe the landscape of cellular glutamine metabolism to search for potential candidates to inhibit glutamine transport or glutamine metabolism.

In Vitro Evaluation of Anti-Rift Valley Fever Virus, Antioxidant and Anti-Inflammatory Activity of South African Medicinal Plant Extracts

Rift valley fever virus (RVFV) is a mosquito-borne virus endemic to sub-Saharan African countries, and the first sporadic outbreaks outside Africa were reported in the Asia-Pacific region. There are no approved therapeutic agents available for RVFV; however, finding an effective antiviral agent against RVFV is important. This study aimed to evaluate the antiviral, antioxidant and anti-inflammatory activity of medicinal plant extracts. Twenty medicinal plants were screened for their anti-RVFV activity using the cytopathic effect (CPE) reduction method. The cytotoxicity assessment of the extracts was done before antiviral screening using the MTT assay. Antioxidant and reactive oxygen/nitrogen species' (ROS/RNS) inhibitory activity by the extracts was investigated using non-cell-based and cell-based assays. Out of twenty plant extracts tested, eight showed significant potency against RVFV indicated by a decrease in tissue culture infectious dose (TCID50) < 105. The cytotoxicity of extracts showed inhibitory concentrations values (IC50) > 200 µg/mL for most of the extracts. The antioxidant activity and anti-inflammatory results revealed that extracts scavenged free radicals exhibiting an IC50 range of 4.12-20.41 µg/mL and suppressed the production of pro-inflammatory mediators by 60-80% in Vero cells. This study demonstrated the ability of the extracts to lower RVFV viral load and their potency to reduce free radicals.

Relevance of oxidative stress in inhibition of eIF2 alpha phosphorylation and stress granules formation during Usutu virus infection

Usutu virus (USUV) is an African mosquito-borne flavivirus closely related to West Nile, Japanese encephalitis, Zika, and dengue viruses. USUV emerged in 1996 in Europe, where quickly spread across the continent causing a considerable number of bird deaths and varied neurological disorders in humans, including encephalitis, meningoencephalitis, or facial paralysis, thus warning about USUV as a potential health threat. USUV replication takes place on the endoplasmic reticulum (ER) of infected cells, inducing ER stress and resulting in the activation of stress-related cellular pathways collectively known as the integrated stress response (ISR). The alpha subunit of the eukaryotic initiation factor eIF2 (eIF2α), the core factor in this pathway, is phosphorylated by stress activated kinases: protein kinase R (PKR), PKR-like endoplasmic reticulum kinase (PERK), heme-regulated inhibitor kinase (HRI), and general control non-repressed 2 kinase (GCN2). Its phosphorylation results, among others, in the downstream inhibition of translation with accumulation of discrete foci in the cytoplasm termed stress granules (SGs). Our results indicated that USUV infection evades cellular stress response impairing eIF2α phosphorylation and SGs assembly induced by treatment with the HRI activator ArsNa. This protective effect was related with oxidative stress responses in USUV-infected cells. Overall, these results provide new insights into the complex connections between the stress response and flavivirus infection in order to maintain an adequate cellular environment for viral replication.

Usutu virus (USUV) infection impairs eIF2α phosphorylation and SGs assembly, in an oxidative stress related manner, as a mechanism to evade cellular stress response. Our results provide new insights into the complex connections between the stress response and USUV infection to maintain a better cellular environment for viral replication.

COVID-19-The Potential Beneficial Therapeutic Effects of Spironolactone during SARS-CoV-2 Infection

In March 2020, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 was declared a global pandemic by the World Health Organization (WHO). The clinical course of the disease is unpredictable but may lead to severe acute respiratory infection (SARI) and pneumonia leading to acute respiratory distress syndrome (ARDS). It has been shown that pulmonary fibrosis may be one of the major long-term complications of COVID-19. In animal models, the use of spironolactone was proven to be an important drug in the prevention of pulmonary fibrosis. Through its dual action as a mineralocorticoid receptor (MR) antagonist and an androgenic inhibitor, spironolactone can provide significant benefits concerning COVID-19 infection. The primary effect of spironolactone in reducing pulmonary edema may also be beneficial in COVID-19 ARDS. Spironolactone is a well-known, widely used and safe anti-hypertensive and antiandrogenic medication. It has potassium-sparing diuretic action by antagonizing mineralocorticoid receptors (MRs). Spironolactone and potassium canrenoate, exerting combined pleiotropic action, may provide a therapeutic benefit to patients with COVID-19 pneumonia through antiandrogen, MR blocking, antifibrotic and anti-hyperinflammatory action. It has been proposed that spironolactone may prevent acute lung injury in COVID-19 infection due to its pleiotropic effects with favorable renin–angiotensin–aldosterone system (RAAS) and ACE2 expression, reduction in transmembrane serine protease 2 (TMPRSS2) activity and antiandrogenic action, and therefore it may prove to act as additional protection for patients at highest risk of severe pneumonia. Future prospective clinical trials are warranted to evaluate its therapeutic potential.

Iron Chelation in Local Infection

Iron is an essential element in multiple biochemical pathways in humans and pathogens. As part of the innate immune response in local infection, iron availability is restricted locally in order to reduce overproduction of reactive oxygen species by the host and to attenuate bacterial growth. This physiological regulation represents the rationale for the therapeutic use of iron chelators to support induced iron deprivation and to treat infections. In this review paper we discuss the importance of iron regulation through examples of local infection and the potential of iron chelation in treating infection.

Oxidative stress, immunological and cellular hypoxia biomarkers in hepatitis C treatment-naïve and cirrhotic patients

INTRODUCTION

Hepatitis C virus (HCV) is the main cause of chronic liver disease, with calamitous complications. Its highest rate is recorded in Egypt. This study investigated whether oxidative stress, immunological chaos and cellular hypoxia are implicated in the pathophysiology of the disease.

MATERIAL AND METHODS

This cross-sectional study aimed to evaluate the changes in blood oxidative stress, cellular hypoxia/angiogenesis and cellular immunological biomarkers in hospital-diagnosed treatment-naïve HCV-infected Upper Egyptian chronic liver disease patients vs. healthy controls (n = 40). The consecutively included patients comprised 120 with normal serum enzymes (HCV-NE) and 130 with high serum enzymes (HCV-HE), along with 120 cirrhotic patients.

RESULTS

Oxidative stress biomarkers - malondialdehyde (MDA), total peroxides and oxidative stress index (OSI) - were significantly lower in controls vs. each of the patient groups. Cirrhotic patients presented the highest levels. However, total antioxidants (TAO) showed non-significant differences among the four groups. The cellular hypoxia/angiogenesis biomarkers - lactate, vascular endothelial cell growth factor (VEGF) and its soluble receptor 1 (sVEGFR1) - vs. controls were massively increased in patient groups. VEGF was lowest while sVEGFR1 was highest among cirrhotic patients. Immunological biomarkers, - granulocyte/monocyte-colony stimulating factor (GM-CSF) and total immunoglobulin G (IgG) - were massively increased in patient groups vs. controls. GM-CSF was lowest in HCV-HE and IgG was highest in cirrhotic patients. sVEGFR1 correlated with the progression towards cirrhosis.

CONCLUSIONS

Oxidative stress is implicated in the progress of HCV infection with marked induction of cellular hypoxia and dysfunctional angiogenesis, and a futile immunological reaction. sVEGFR1 level correlated with progression towards HCV-induced liver fibrosis.

Allicin Attenuated Advanced Oxidation Protein Product-Induced Oxidative Stress and Mitochondrial Apoptosis in Human Nucleus Pulposus Cells

Intervertebral disc degeneration (IDD) is one of the most common chronic degenerative musculoskeletal disorders. Oxidative stress-induced apoptosis of the nucleus pulposus (NP) cells plays a key role during IDD progression. Advanced oxidation protein products (AOPP), novel biomarkers of oxidative stress, have been reported to function in various diseases due to their potential for disrupting the redox balance. The current study is aimed at investigating the function of AOPP in the oxidative stress-induced apoptosis of human NP cells and the alleviative effects of allicin during this process which was known for its antioxidant properties. AOPP were demonstrated to hamper the viability and proliferation of NP cells in a time- and concentration-dependent manner and cause cell apoptosis markedly. High levels of reactive oxygen species (ROS) and lipid peroxidation product malondialdehyde (MDA) were detected in NP cells after AOPP stimulation, which resulted in depolarized mitochondrial transmembrane potential (MTP). Correspondingly, higher levels of AOPP were discovered in the human degenerative intervertebral discs (IVD). It was also found that allicin could protect NP cells against AOPP-mediated oxidative stress and mitochondrial dysfunction via suppressing the p38-MAPK pathway. These results disclosed a significant role of AOPP in the oxidative stress-induced apoptosis of NP cells, which could be involved in the primary pathogenesis of IDD. It was also revealed that allicin could be a promising therapeutic approach against AOPP-mediated oxidative stress during IDD progression.

Changes in oxidation-antioxidation function on the thymus of chickens infected with reticuloendotheliosis virus

Background

Reticuloendotheliosis virus (REV) is a retrovirus that causes severe immunosuppression in poultry. Animals grow slowly under conditions of oxidative stress. In addition, long-term oxidative stress can impair immune function, as well as accelerate aging and death. This study aimed to elucidate the pathogenesis of REV from the perspective of changes in oxidative-antioxidative function following REV infection.

Methods

A total of 80 one-day-old specific pathogen free (SPF) chickens were randomly divided into a control group (Group C) and an REV-infected group (Group I). The chickens in Group I received intraperitoneal injections of REV with 10^4.62/0.1 mL TCID₅₀. Thymus was collected on day 1, 3, 7, 14, 21, 28, 35, and 49 for histopathology and assessed the status of oxidative stress.

Results

In chickens infected with REV, the levels of H₂O₂ and MDA in the thymus increased, the levels of TAC, SOD, CAT, and GPx1 decreased, and there was a reduction in CAT and Gpx1 mRNA expression compared with the control group. The thymus index was also significantly reduced. Morphological analysis showed that REV infection caused an increase in the thymic reticular endothelial cells, inflammatory cell infiltration, mitochondrial swelling, and nuclear damage.

Conclusions

These results indicate that an increase in oxidative stress enhanced lipid peroxidation, markedly decreased antioxidant function, caused thymus atrophy, and immunosuppression in REV-infected chickens.

Impact of Zika Virus Infection on Human Neural Stem Cell MicroRNA Signatures

Zika virus (ZIKV) is a mosquito-borne virus, which can cause brain abnormalities in newborns, including microcephaly. MicroRNAs (miRNAs) are small non-coding RNAs, which post- transcriptionally regulate gene expression. They are involved in various processes including neurological development and host responses to viral infection, but their potential role in ZIKV pathogenesis remains poorly understood. MiRNAs can be incorporated into extracellular vesicles (EVs) and mediate cell-to-cell communication. While it is well known that in viral infections EVs carrying miRNAs can play a crucial role in disease pathogenesis, ZIKV effects on EV-delivered miRNAs and their contribution to ZIKV pathogenesis have not been elucidated. In the present study, we profiled intracellular and EV-derived miRNAs by next generation sequencing and analyzed the host mRNA transcriptome of neural stem cells during infection with ZIKV Uganda and French Polynesia strains. We identified numerous miRNAs, including miR-4792, which were dysregulated at the intracellular level and had altered levels in EVs during ZIKV infection. Integrated analyses of differentially expressed genes and miRNAs showed that ZIKV infection had an impact on processes associated with neurodevelopment and oxidative stress. Our results provide insights into the roles of intracellular and EV-associated host miRNAs in ZIKV pathogenesis.

Natural Antioxidants: A Review of Studies on Human and Animal Coronavirus

The outbreaks of viruses with wide spread and mortality in the world population have motivated the research for new therapeutic approaches. There are several viruses that cause a biochemical imbalance in the infected cell resulting in oxidative stress. These effects may be associated with the development of pathologies and worsening of symptoms. Therefore, this review is aimed at discussing natural compounds with both antioxidant and antiviral activities, specifically against coronavirus infection, in an attempt to contribute to global researches for discovering effective therapeutic agents in the treatment of coronavirus infection and its severe clinical complications. The contribution of the possible action of these compounds on metabolic modulation associated with antiviral properties, in addition to other mechanisms of action, is presented.

Roles of Macrophage Migration Inhibitory Factor in Dengue Pathogenesis: From Pathogenic Factor to Therapeutic Target

Dengue virus (DENV) infection is the most prevalent mosquito-borne viral infection and can lead to severe dengue hemorrhagic fever (DHF) and even life-threatening dengue shock syndrome (DSS). Although the cytokine storm has been revealed as a critical factor in dengue disease, the limited understanding of dengue immunopathogenesis hinders the development of effective treatments. Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine that mediates diverse immune responses, and the serum level of MIF positively correlates with disease severity in patients with dengue. MIF is involved in DENV replication and many pathological changes, such as vascular leakage, during DENV infection. In this paper, the pathogenic roles of MIF and the regulation of MIF secretion during DENV infection are reviewed. Furthermore, whether MIF is a potential therapeutic target against DENV infection is also discussed.