Redox imbalance in COVID-19 pathophysiology

Bioinformatics and systems-biology approach to identify common pathogenic mechanisms for COVID-19 and systemic lupus erythematosus

BACKGROUND

The Coronavirus disease 2019 (COVID-19) pandemic has brought a heavy burden to the world, interestingly, it shares many clinical symptoms with systemic lupus erythematosus (SLE). It is unclear whether there is a similar pathological process between COVID-9 and SLE. In addition, we don't know how to treat SLE patients with COVID-19. In this study, we analyse the potential similar pathogenesis between SLE and COVID-19 and explore their possible drug regimens using bioinformatics and systems biology approaches.

METHODS

The common differentially expressed genes (DEGs) were extracted from the COVID-19 datasets and the SLE datasets for functional enrichment, pathway analysis and candidate drug analysis.

RESULT

Based on the two transcriptome datasets between COVID-19 and SLE, 325 common DEGs were selected. Hub genes were identified by protein-protein interaction (PPI) analysis. few found a variety of similar functional changes between COVID-19 and SLE, which may be related to the pathogenesis of COVID-19. Besides, we explored the related regulatory networks. Then, through drug target matching, we found many candidate drugs for patients with COVID-19 only or COVID-19 combined with SLE.

CONCLUSION

COVID-19 and SLE patients share many common hub genes, related pathways and regulatory networks. Based on these common targets, we found many potential drugs that could be used in treating patient with COVID-19 or COVID-19 combined with SLE.

Systemic oxidative stress associates with the development of post-COVID-19 syndrome in non-hospitalized individuals

BACKGROUND

Post-COVID-19 syndrome (PCS) remains a major health issue worldwide, while its pathophysiology is still poorly understood. Systemic oxidative stress (OS) may be involved in PCS, which is reflected by lower circulating free thiols (R-SH, sulfhydryl groups), as they are receptive to rapid oxidation by reactive species. This study aimed to investigate the longitudinal dynamics of serum R-SH after SARS-CoV-2 infection and its association with the development of PCS in individuals with mild COVID-19.

METHODS

Baseline serum R-SH concentrations were measured and compared between 135 non-hospitalized COVID-19 subjects and 82 healthy controls (HC). In COVID-19 subjects, serum R-SH concentrations were longitudinally measured during the acute disease phase (up to 3 weeks) and at 3, 6, and 12 months of follow-up, and their associations with relevant clinical parameters were investigated, including the development of PCS.

RESULTS

Baseline albumin-adjusted serum R-SH were significantly reduced in non-hospitalized COVID-19 subjects as compared to HC (p = 0.041), reflecting systemic OS. In mild COVID-19 subjects, trajectories of albumin-adjusted serum R-SH levels over a course of 12 months were longitudinally associated with the future presence of PCS 18 months after initial infection (b = -9.48, p = 0.023).

CONCLUSION

Non-hospitalized individuals with COVID-19 show evidence of systemic oxidative stress, which is longitudinally associated with the development of PCS. Our results provide a rationale for future studies to further investigate the value of R-SH as a monitoring biomarker and a potential therapeutic target in the development of PCS.

An electron paramagnetic resonance time-course study of oxidative stress in the plasma of electronic cigarette exposed rats

The long-term consequences of electronic cigarette (Ecig) use in humans are not yet known, but it is known that Ecig aerosols contain many toxic compounds of concern. We have recently shown that Ecig exposure impairs middle cerebral artery (MCA) endothelial function and that it takes 3 days for MCA reactivity to return to normal. However, the sources contributing to impairment of the endothelium were not investigated. We hypothesized that the increased levels of oxidative stress markers in the blood are correlated with impaired MCA reactivity. We used electron paramagnetic resonance (EPR) spectroscopy to examine plasma from 4-month-old male Sprague-Dawley rats that were exposed to either air (n = 5) or 1 h Ecig exposure, after which blood samples were collected at varying times after exposure (i.e., 1-4, 24, 48 and 72 h postexposure, n = 4 or 5 in each time group). The EPR analyses were performed using the redox-sensitive hydroxylamine spin probe 1-hydroxy-3-carboxymethyl-2,2,5,5-tetramethyl-pyrrolidine (CMH) to measure the level of reactive oxidant species in the plasma samples. We found that EPR signal intensity from the CM• radical was significantly increased in plasma at 1-4, 24 and 48 h (P < 0.05, respectively) and returned to control (air) levels by 72 h. When evaluating the EPR results with MCA reactivity, we found a significant negative correlation (Pearson's P = 0.0027). These data indicate that impaired cerebrovascular reactivity resulting from vaping is associated with the oxidative stress level (measured by EPR from plasma) and indicate that a single 1 h vaping session can negatively influence vascular health for up to 3 days after vaping. HIGHLIGHTS: What is the central question of this study? Does the time course of oxidative stress triggered by electronic cigarette exposure follow the cerebral vascular dysfunction? What is the main finding and its importance? Electron paramagnetic resonance analysis shows that the oxidative stress induced after a single 1 h exposure to electronic cigarette aerosol takes ≤72 h to return to normal, which mirrors the time course for vascular dysfunction in the middle cerebral artery that we have reported previously.

Maternal use of electronic cigarettes and impact on offspring: a double-hit model

Endothelial dysfunction is a predictor for cardiovascular disease. Preclinical data suggest longstanding cardiovascular and cerebrovascular dysfunction occurs in offspring with perinatal electronic cigarette (Ecig) exposure. Furthermore, direct use of Ecigs increases reactive oxygen species and impairs cerebrovascular function, but the combined effect of direct use in offspring with a history of perinatal exposure (i.e. double-hit condition) is not known. We tested the hypothesis that offspring with double-hit Ecig exposure will lead to greater cerebrovascular and neurocognitive dysfunction compared with in utero exposure only. Male and female offspring were obtained from time-mated Sprague Dawley female rats exposed to air (n = 5 dams) or Ecig exposed (n = 5 dams) and studied at either 3 or 6 mo after birth. Ecig exposure for double-hit offspring began at 1-mo before the timepoints and lasted 4 wk (5 days/wk with 90-min exposure/day). We found double-hit offspring (Ecig:Ecig = exposure dam:offspring) sustained further blunted middle cerebral artery (MCA) reactivity, increased severity of neuronal damage, and increased interactions of astrocytes and endothelial cells compared with offspring with maternal (Ecig:Air) or direct (Air:Ecig) exposure only. Circulating extracellular vesicles (EVs) were increased, whereas sirtuin 1 (SIRT1) was decreased, in all Ecig-exposed groups compared with controls (Air:Air), with Ecig:Ecig group showing the greatest respective change for each. Electron paramagnetic resonance (EPR) spectroscopy revealed oxidative stress was the highest in the plasma of Ecig:Ecig group (P < 0.05) than the other groups. These data show that a double-hit exposure in adolescent or adult offspring results in a greater decline in cerebrovascular function, biomarkers of neuronal dysfunction, and increased circulation of EVs compared with a single-hit exposure.NEW & NOTEWORTHY These data add to the growing body of literature demonstrating that electronic cigarette (Ecig) use during pregnancy (even without nicotine) is not safe, and primes offspring to have worse cardiovascular health outcomes in early and adult life. A key finding from this work is that a second insult from direct vaping in offspring with prior in utero exposure induces greater vascular dysfunction, increased oxidative stress, and shows evidence of neuronal dysfunction compared with either direct- or maternal-only exposure.

Clinical characteristics of a COVID-19 cohort treated at UCLA Ronald Reagan Medical Center during the breaking phase of the pandemic: A retrospective study

To this date, COVID-19 remains an unresolved pandemic, and the impairment of redox homeostasis dictates the severity of clinical outcomes. Here we examined initial UCLA cohort of 440 COVID-19 patients hospitalized between March 1st and April 1st, 2020, representing the first wave of the pandemic. The mean age was 58.88 ± 21.12, among which males were significantly more than females (55.5 % vs. 44.5 %), most distinctively in age group of 50-69. The age groups of 50-69 (33.6 %) and ≥70 (34.8 %) dominated. The racial composition was in general agreement with Census data with slight under-representation of Hispanics and Asians, and over-representation of Caucasians. Smoking was a significant factor (28.8 % vs. 11.0 % in LA population), likewise for obesity (BMI ≥30) (37.4 % vs. 27.7 % in LA population). Patients suffering from obesity or BMI<18.5 checked into ICU at a significantly higher rate. A 74.5 % of the patients had comorbidities including diabetes, chronic kidney disease, chronic pulmonary disease, congestive heart failure and peripheral vascular disease. The levels of d-dimer were drastically upregulated (1159.5 ng/mL), indicating hypercoagulative state. Upregulated LDH (328 IU/L) indicated significant tissue damages. A distorted redox hemeostasis is a common trait associated with these risk factors and clinical markers. A quarter of the patients received antivirals, among which Remdesivir most prescribed (23.6 %). Majority received antithrombotics (75 %), and antibiotics. Upon admission, 67 patients were intubated or received CPR; 177 patients eventually received intensive care (40.2 %). While 290 were discharged alive, 10 remained hospitalized, 73 were transferred, and 36 died with 3 palliatively discharged. In summary, our data fully characterized a Californian cohort of COVID-19 at the breaking phase of the pandemic, indicating that population demographics, biophysical characters, comorbidities and molecular pathological parameters have significant impacts on the evolvement of a pandemic. These provide critical insights into effective management of COVID-19, and future break from another pathogen.

Nitrite Attenuates the In Vitro Inflammatory Response of Immune Cells to the SARS-CoV-2 S Protein without Interfering in the Antioxidant Enzyme Activation

SARS-CoV-2 induces a hyperinflammatory reaction due to the excessive release of cytokines during the immune response. The bacterial endotoxin lipopolysaccharide (LPS) contributes to the low-grade inflammation associated with the metabolic syndrome, enhancing the hyperinflammatory reaction induced by the SARS-CoV-2 infection. The intake of sodium nitrate, a precursor of nitrite and nitric oxide, influences the antioxidant and pro-inflammatory gene expression profile after immune stimulation with LPS in peripheral blood mononuclear cells from metabolic syndrome patients. We aimed to assess the inflammatory and antioxidant responses of immune cells from metabolic syndrome patients to exposure to the SARS-CoV-2 spike protein (S protein) together with LPS and the effect of nitrite in these responses. Whole blood samples obtained from six metabolic syndrome patients were cultured for 16 h at 37 °C with four different media: control medium, control medium plus LPS (100 ng/mL), control medium plus LPS (100 ng/mL) plus S protein (10 ng/mL), and control medium plus LPS (100 ng/mL) plus S protein (10 ng/mL) plus nitrite (5 µM). Immune stimulation with the LPS/S protein enhanced nitrate biosynthesis from nitrite oxidation and probably from additional organic precursors. In vitro incubations with the LPS/S protein enhanced the expression and/or release of pro-inflammatory TNFα, IL-6, IL-1β, and TLR4, as well as the expression of the anti-inflammatory IL-1ra and IL-10 and antioxidant enzymes. Nitrite attenuated the pro- and anti-inflammatory response induced by the S protein without interfering with the activation of TLR4 and antioxidant enzyme expression, raising the possibility that nitrite could have potential as a coadjutant in the treatment of COVID-19.

A pilot study of mitochondrial response to an in vivo prosthetic joint Staphylococcus aureus infection model

Prosthetic joint infections (PJI) are associated with orthopaedic morbidity and mortality. Mitochondria, the "cell's powerhouses," are thought to play crucial roles in infection response and in increased risk of sepsis mortality. No current research discusses PJI's effect on mitochondrial function and a lack of understanding of immune-infection interactions potentially hinders patient care. The purpose of this pilot study was to evaluate the impact of simulated PJI on local tissue mitochondrial function. Using an established prosthetic implant-associated in vivo model, tissues were harvested from the surgical limb of a methicillin-sensitive Staphylococcus aureus implant-associated infection group (n = 6) and compared to a noninfected group (n = 6) at postoperative day (POD) 21. Using mitochondrial coupling assays, oxygen consumption rate and extracellular acidification rate were assessed in each group. Electron flow through mitochondrial complexes reflected group activity. Electron Paramagnetic Resonance (EPR) spectrometry measured the oxidizing potential of serum samples from infected versus noninfected groups. On POD21, colony-forming units per gram of tissue showed 5 × 109 in the infected group and 101 in the noninfected group (p < 0.0001). Maximal respiration and oxygen consumption due to adenosine triphosphate synthesis were significantly lower in isolated mitochondria from infected limbs (p = 0.04). Both groups had similar complex I, III, IV, and V activity (p > 0.1). Infected group EPR signal intensity reflecting reactive oxygen species levels was 1.31 ± 0.30 compared to 1.16 ± 0.28 (p = 0.73) in the noninfected group. This study highlights PJI's role in mammalian cell mitochondrial dysfunction and oxidative tissue damage, which can help develop interventions to combat PJI.

Superoxide dismutase alterations in COVID-19: implications for disease severity and mortality prediction in the context of omicron variant infection

Background

In the few reports to date, the changes in superoxide dismutase (SOD), a key factor in cellular protection against superoxide, in COVID-19 have been very inconsistent and contradictory. There is also a lack of data on COVID-19 induced by Omicron variant. Further investigation is warranted to figure out SOD alterations in COVID-19, particularly within the context of ongoing Omicron variant infection, which may provide clues to its role within COVID-19 pathogenesis and open up new avenues for COVID-19 treatment.

Methods

SOD activity in 109 COVID-19 patients (including 46 severe cases and 63 mild to moderate cases) and 30 matched healthy controls were quantified. Demographic data, blood cell counts, biochemical indicators, coagulation indicators, and inflammatory markers were also recorded.

Results

SOD, an important key node, experienced a significant decrease in COVID-19, with the severe patients exhibiting lower activity compared to the mild to moderate patients and control healthy. Notably, severe patients who deceased had the lowest SOD activity. Correlation analysis revealed significant correlations between SOD and inflammatory markers, organ injury markers, coagulation dysfunction indicators, nutritional markers, and lymphocytes counts. The ROC curve also showed good performance for the differentiation of severe cases and the prediction of death.

Conclusion

SOD activity was significantly decreased in COVID-19 infected with Omicron variant and significantly correlated with systemic changes, and could be used as a biomarker to assess disease severity and predict mortality in COVID-19 clinical pathway management. Additionally, this finding will contribute to exploring new potential direction for the treatment of severe COVID-19 patients.

Immune landscape and redox imbalance during neurological disorders in COVID-19

The outbreak of Coronavirus Disease 2019 (COVID-19) has prompted the scientific community to explore potential treatments or vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the illness. While SARS-CoV-2 is mostly considered a respiratory pathogen, several neurological complications have been reported, raising questions about how it may enter the Central Nervous System (CNS). Receptors such as ACE2, CD147, TMPRSS2, and NRP1 have been identified in brain cells and may be involved in facilitating SARS-CoV-2 entry into the CNS. Moreover, proteins like P2X7 and Panx-1 may contribute to the pathogenesis of COVID-19. Additionally, the role of the immune system in the gravity of COVID-19 has been investigated with respect to both innate and adaptive immune responses caused by SARS-CoV-2 infection, which can lead to a cytokine storm, tissue damage, and neurological manifestations. A redox imbalance has also been linked to the pathogenesis of COVID-19, potentially causing mitochondrial dysfunction, and generating proinflammatory cytokines. This review summarizes different mechanisms of reactive oxygen species and neuro-inflammation that may contribute to the development of severe COVID-19, and recent progress in the study of immunological events and redox imbalance in neurological complications of COVID-19, and the role of bioinformatics in the study of neurological implications of COVID-19.

A Comparison of Etiology, Pathogenesis, Vaccinal and Antiviral Drug Development between Influenza and COVID-19

Influenza virus and coronavirus, two kinds of pathogens that exist widely in nature, are common emerging pathogens that cause respiratory tract infections in humans. In December 2019, a novel coronavirus SARS-CoV-2 emerged, causing a severe respiratory infection named COVID-19 in humans, and raising a global pandemic which has persisted in the world for almost three years. Influenza virus, a seasonally circulating respiratory pathogen, has caused four global pandemics in humans since 1918 by the emergence of novel variants. Studies have shown that there are certain similarities in transmission mode and pathogenesis between influenza and COVID-19, and vaccination and antiviral drugs are considered to have positive roles as well as several limitations in the prevention and control of both diseases. Comparative understandings would be helpful to the prevention and control of these diseases. Here, we review the study progress in the etiology, pathogenesis, vaccine and antiviral drug development for the two diseases.

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.