The role of HMGB1 in COVID-19-induced cytokine storm and its potential therapeutic targets: A review.

Hyperinflammation characterized by elevated proinflammatory cytokines known as 'cytokine storms' is the major cause of high severity and mortality seen in COVID-19 patients. The pathology behind the cytokine storms is currently unknown. Increased HMGB1 levels in serum/plasma of COVID-19 patients were reported by many studies, which positively correlated with the level of proinflammatory cytokines. Dead cells following SARS-CoV-2 infection might release a large amount of HMGB1 and RNA of SARS-CoV-2 into extracellular space. HMGB1 is a well-known inflammatory mediator. Additionally, extracellular HMGB1 might interact with SARS-CoV-2 RNA because of its high capability to bind with a wide variety of molecules including nucleic acids and could trigger massive proinflammatory immune responses. This review aimed to critically explore the many possible pathways by which HMGB1-SARS-CoV-2 RNA complexes mediate proinflammatory responses in COVID-19. The contribution of these pathways to impair host immune responses against SARS-CoV-2 infection leading to a cytokine storm was also evaluated. Moreover, since blocking the HMGB1-SARS-CoV-2 RNA interaction might have therapeutic value, some of the HMGB1 antagonists have been reviewed. The HMGB1- SARS-CoV-2 RNA complexes might trigger endocytosis via RAGE which is linked to lysosomal rupture, PRRs activation, and pyroptotic death. High levels of the proinflammatory cytokines produced might suppress many immune cells leading to uncontrolled viral infection and cell damage with more HMGB1 released. Altogether these mechanisms might initiate a proinflammatory cycle leading to a cytokine storm. HMGB1 antagonists could be considered to give benefit in alleviating cytokine storms and serve as a potential candidate for COVID-19 therapy.

Huashibaidu formula attenuates sepsis-induced acute lung injury via suppressing cytokine storm: Implications for treatment of COVID-19.

BACKGROUND: Acute lung injury (ALI) is a common complication of sepsis with poor effective interventions. Huashibaidu formula (HSBD) showed good therapeutic effects in treating coronavirus disease 2019 (COVID-19) patients. PURPOSE: This study was designed to investigate the therapeutic potential and precise mechanism of HSBD against sepsis-induced ALI based on network pharmacology and animal experiments. MATERIALS AND METHODS: Network pharmacology was used to predict the possible mechanism of HSBD against sepsis. Next, a sepsis-induced ALI rat model via intraperitoneal lipopolysaccharide (LPS) was constructed to evaluate the level of inflammatory cytokines and the degree of lung injury. The expression of inflammation-related signaling pathways, including TLR4/NF-κB and PI3K/Akt was determined by western blot. RESULTS: Network pharmacology analysis indicated that HSBD might have a therapeutic effect on sepsis mainly by affecting inflammatory and immune responses. Animal experiments demonstrated that HSBD protected the lung tissue from LPS-induced injury, and inhibited the levels of inflammatory cytokines such as interleukin (IL)-1ß, granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon (IFN)-γ and tumor necrosis factor (TNF)-α in the serum and IL-1ß, IL-5, IL-6, IL-18, GM-CSF, IFN-γ and TNF-α in the lung tissue. Western blot results revealed that HSBD downregulated the expression of TLR4/NF-κB and upregulated the expression of PI3K/Akt. CONCLUSION: The therapeutic mechanism of HSBD against sepsis-induced ALI mainly involved suppressing cytokine storms and relieving inflammatory symptoms by regulating the expression of TLR4/NF-κB and PI3K/Akt. Our study provides a scientific basis for the mechanistic investigation and clinical application of HSBD in the treatment of sepsis and COVID-19.

Interplay of LncRNAs NEAT1 and TUG1 in Incidence of Cytokine Storm in Appraisal of COVID-19 Infection.

Background: In 2019, the coronavirus pandemic emerged, resulting in the highest mortality and morbidity rate globally. It has a prevailing transmission rate and continues to be a global burden. There is a paucity of data regarding the role of long non-coding RNAs (lncRNAs) in COVID-19. Therefore, the current study aimed to investigate lncRNAs, particularly NEAT1 and TUG1, and their association with IL-6, CCL2, and TNF-α in COVID-19 patients with moderate and severe disease. Methods: The study was conducted on 80 COVID-19 patients (35 with severe and 45 with moderate infection) and 40 control subjects. Complete blood count (CBC), D-dimer assay, serum ferritin, and CRP were assayed. qRT-PCR was used to measure RNAs and lncRNAs. Results: NEAT1 and TUG1 expression levels were higher in COVID-19 patients compared with controls (P<0.001). Furthermore, CCL2, IL-6, and TNF-α expressions were higher in COVID-19 patients compared to controls (P<0.001). CCL2 and IL-6 expression levels were significantly higher in patients with severe compared to those with moderate COVID-19 infection (P<0.001). IL-6 had the highest accuracy in distinguishing COVID-19 patients (AUC=1, P<0.001 at a cutoff of 0.359), followed by TUG1 (AUC=0.999, P<0.001 at a cutoff of 2.28). NEAT1 and TUG1 had significant correlations with the measured cytokines, and based on the multivariate regression analysis, NEAT1 is the independent predictor for survival in COVID-19 patients (P=0.02). Conclusion: In COVID-19 patients, significant overexpression of NEAT1 and TUG1 was observed, consistent with cytokine storm. TUG1 could be an efficient diagnostic biomarker, whereas NEAT1 was an independent predictor for overall survival.

Highlights of clinical and laboratory parameters among severe COVID-19 patients treated with tocilizumab: a retrospective observational study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) can cause cytokine release syndrome (CRS), which leads to high mortality rates. Tocilizumab suppresses CRS by blocking the signal transduction of interleukin-6 (IL-6). OBJECTIVE: To evaluate the clinical and laboratory parameters associated with mortality among patients receiving tocilizumab treatment. DESIGN AND SETTING: Retrospective observational study conducted in the chest disease departments of two different training and research hospitals in the center of Ankara, Turkey. METHODS: Patients who were hospitalized and treated with tocilizumab in September 2020 were retrospectively analyzed. Their laboratory parameters and clinical characteristics were obtained from the hospital information system database. Comparative analyses were performed between the patients who died and the ones who survived. RESULTS: A total of 58 patients who received tocilizumab treatment were included in this study, among whom 35 (60.3%) died. There was no difference between the mortality and survival groups in terms of white blood cell (WBC), neutrophil, lymphocyte, ferritin or C-reactive protein (CRP) levels detected on admission. WBC, lymphocyte, neutrophil and CRP levels measured on the third and fifth days after tocilizumab administration were found to be significantly lower in the survival group (P < 0.05). In multiple logistic regression analysis, age and oxygen saturation were determined to be independent risk factors for mortality. CONCLUSION: Persistently high WBC, CRP and neutrophil levels and low lymphocyte levels could be considered to be valuable indicators of mortality among COVID-19 patients treated with tocilizumab. Age and low oxygen saturation are independent risk factors for mortality among patients receiving tocilizumab treatment.

Human cardiac organoids to model COVID-19 cytokine storm induced cardiac injuries.

Acute cardiac injuries occur in 20%-25% of hospitalized COVID-19 patients. Herein, we demonstrate that human cardiac organoids (hCOs) are a viable platform to model the cardiac injuries caused by COVID-19 hyperinflammation. As IL-1ß is an upstream cytokine and a core COVID-19 signature cytokine, it was used to stimulate hCOs to induce the release of a milieu of proinflammatory cytokines that mirror the profile of COVID-19 cytokine storm. The IL-1ß treated hCOs recapitulated transcriptomic, structural, and functional signatures of COVID-19 hearts. The comparison of IL-1ß treated hCOs with cardiac tissue from COVID-19 autopsies illustrated the critical roles of hyper-inflammation in COVID-19 cardiac insults and indicated the cardioprotective effects of endothelium. The IL-1ß treated hCOs thus provide a defined and robust model to assess the efficacy and potential side effects of immunomodulatory drugs, as well as the reversibility of COVID-19 cardiac injuries at baseline and simulated exercise conditions.

Comment on Kopanska et al. Disorders of the Cholinergic System in COVID-19 Era-A Review of the Latest Research. Int. J. Mol. Sci. 2022, 23, 672.

We read the recent review article by Marta Kopanska et al. [...].

Mutational Analysis of Interleukin-11 and its Consequences on Cancer and COVID-19 Related Cytokine Storm -An Extensive Molecular Dynamics Study.

BACKGROUND: Interleukin-11 is a pleiotropic cytokine that is known to play an important role in the progression of various forms of cancer by modulating the survival and proliferation of tumour cells. IL11 also demonstrates a structural homology to IL6, the predominant cytokine involved in COVID-19. This makes IL11 a potential therapeutic target in both diseases. OBJECTIVE: This study aimed to evaluate the impact of the two-point mutations, R135E and R190E, on the stability of IL11 and their effect on the binding affinity of IL11 with its receptor IL11Rα. It is a molecular level analysis based on the existing experimental validation. METHODS: Computer-aided drug designing techniques, such as molecular modelling, molecular docking, and molecular dynamics simulations, were employed to determine the consequential effects of the two-point mutations. RESULTS: Our analysis revealed that the two mutations led to a decrease in the overall stability of IL11. This was evident by the increased atomic fluctuations in the mutated regions as well as the corresponding elevation in the deviations seen through RMSD and Rg values. It was also accompanied by a loss in the secondary structural organisation in the mutated proteins. Moreover, mutation R135E led to an increase in the binding affinity of IL11 with IL11Rα and the formation of a more stable complex in comparison to the wild-type protein with its receptor. CONCLUSION: Mutation R190E led to the formation of a less stable complex than the wild-type, which suggests a decrease in the binding affinity between IL11 and IL11Rα.

Coping With Stress: The Mitokine GDF-15 as a Biomarker of COVID-19 Severity.

Growth differentiation factor 15 (GDF-15) is a transforming growth factor (TGF)-ß superfamily cytokine that plays a central role in metabolism regulation. Produced in response to mitochondrial stress, tissue damage or hypoxia, this cytokine has emerged as one of the strongest predictors of disease severity during inflammatory conditions, cancers and infections. Reports suggest that GDF-15 plays a tissue protective role via sympathetic and metabolic adaptation in the context of mitochondrial damage, although the exact mechanisms involved remain uncertain. In this review, we discuss the emergence of GDF-15 as a distinctive marker of viral infection severity, especially in the context of COVID-19. We will critically review the role of GDF-15 as an inflammation-induced mediator of disease tolerance, through metabolic and immune reprogramming. Finally, we discuss potential mechanisms of GDF-15 elevation during COVID-19 cytokine storm and its limitations. Altogether, this cytokine seems to be involved in disease tolerance to viral infections including SARS-CoV-2, paving the way for novel therapeutic interventions.

The mechanism underlying extrapulmonary complications of the coronavirus disease 2019 and its therapeutic implication.

The coronavirus disease 2019 (COVID-19) is a highly transmissible disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that poses a major threat to global public health. Although COVID-19 primarily affects the respiratory system, causing severe pneumonia and acute respiratory distress syndrome in severe cases, it can also result in multiple extrapulmonary complications. The pathogenesis of extrapulmonary damage in patients with COVID-19 is probably multifactorial, involving both the direct effects of SARS-CoV-2 and the indirect mechanisms associated with the host inflammatory response. Recognition of features and pathogenesis of extrapulmonary complications has clinical implications for identifying disease progression and designing therapeutic strategies. This review provides an overview of the extrapulmonary complications of COVID-19 from immunological and pathophysiologic perspectives and focuses on the pathogenesis and potential therapeutic targets for the management of COVID-19.

AKR1B10, One of the Triggers of Cytokine Storm in SARS-CoV2 Severe Acute Respiratory Syndrome.

Preventing the cytokine storm observed in COVID-19 is a crucial goal for reducing the occurrence of severe acute respiratory failure and improving outcomes. Here, we identify Aldo-Keto Reductase 1B10 (AKR1B10) as a key enzyme involved in the expression of pro-inflammatory cytokines. The analysis of transcriptomic data from lung samples of patients who died from COVID-19 demonstrates an increased expression of the gene encoding AKR1B10. Measurements of the AKR1B10 protein in sera from hospitalised COVID-19 patients suggests a significant link between AKR1B10 levels and the severity of the disease. In macrophages and lung cells, the over-expression of AKR1B10 induces the expression of the pro-inflammatory cytokines Interleukin-6 (IL-6), Interleukin-1ß (IL-1ß) and Tumor Necrosis Factor a (TNFα), supporting the biological plausibility of an AKR1B10 involvement in the COVID-19-related cytokine storm. When macrophages were stressed by lipopolysaccharides (LPS) exposure and treated by Zopolrestat, an AKR1B10 inhibitor, the LPS-induced production of IL-6, IL-1ß, and TNFα is significantly reduced, reinforcing the hypothesis that the pro-inflammatory expression of cytokines is AKR1B10-dependant. Finally, we also show that AKR1B10 can be secreted and transferred via extracellular vesicles between different cell types, suggesting that this protein may also contribute to the multi-organ systemic impact of COVID-19. These experiments highlight a relationship between AKR1B10 production and severe forms of COVID-19. Our data indicate that AKR1B10 participates in the activation of cytokines production and suggest that modulation of AKR1B10 activity might be an actionable pharmacological target in COVID-19 management.

Cytokine Storm and Failed Resolution in COVID-19: Taking a Cue from Multiple Sclerosis.

INTRODUCTION: Excessive inflammatory responses and failed resolution are major common causes of tissue injury and organ dysfunction in a variety of diseases, including multiple sclerosis (MS), diabetes, and most recently, COVID-19, despite the distinct pathoetiology of the diseases. The promotion of the natural process of inflammatory resolution has been long recognized to improve functional recovery and disease outcomes effectively. To mitigate the excessive inflammation in MS, scientific investigations identified a group of derivatives of omega fatty acids, known as specialized pro-resolving lipid mediators (SPM) that have been significantly effective in treating preclinical disease models of MS. METHODS: This chapter is based on our observations from MS. It is being increasingly deliberated that the ongoing COVID-19 infection induces severe cytokine storm that ultimately triggers rampant inflammation. The impact of infection and associated mortality is much higher in patients with co-morbid diseases. Also, reports suggest a better outcome in diabetic patients with reasonable glycemic control, which certainly hints towards a hidden role of anti-hyperglycemic drugs such as metformin in alleviating disease pathology through its anti-inflammatory feature. Notably, SPM and metformin share common therapeutic features in exerting a broad-spectrum anti-inflammatory activity in human patients with a superior safety profile. RESULTS: When there is an immediate need to encounter the fast-rampant infection of COVID-19 and control the viral-infection associated morbid inflammatory cytokine storm causing severe organ damage, SPM and metformin should be seriously considered as a potential adjunctive treatment. CONCLUSION: Given the fact that current treatment for COVID-19 is only supportive, global research is aimed at developing safe and effective therapeutic options that can result in a better clinical course in patients with comorbid conditions. Accordingly, taking a cue from our experiences in controlling robust inflammatory response in MS and diabetes by simultaneously inhibiting inflammatory process and stimulating its resolution, combinatorial therapy of metformin and SPM in COVID-19 holds significant promise in treating this global health crisis.

Is COVID-19-associated cytokine storm distinct from non-COVID-19 secondary hemophagocytic lymphohistiocytosis?

Cytokine storm is an umbrella term that describes an inflammatory syndrome characterized by elevated levels of circulating cytokines and hyperactivation of innate and/or adaptive immune cells. One type of cytokine storm is hemophagocytic lymphohistiocytosis (HLH), which can be either primary or secondary. Severe COVID-19-associated pneumonia and acute respiratory distress syndrome (ARDS) can also lead to cytokine storm/cytokine release syndrome (CS/CRS) and, more rarely, meet criteria for the diagnosis of secondary HLH. Here, we review the immunobiology of primary and secondary HLH and examine whether COVID-19-associated CS/CRS can be discriminated from non-COVID-19 secondary HLH. Finally, we review differences in immunobiology between these different entities, which may inform both clinical diagnosis and treatment of patients.

Coagulation System Activation for Targeting of COVID-19: Insights into Anticoagulants, Vaccine-Loaded Nanoparticles, and Hypercoagulability in COVID-19 Vaccines.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as COVID-19, is currently developing into a rapidly disseminating and an overwhelming worldwide pandemic. In severe COVID-19 cases, hypercoagulability and inflammation are two crucial complications responsible for poor prognosis and mortality. In addition, coagulation system activation and inflammation overlap and produce life-threatening complications, including coagulopathy and cytokine storm, which are associated with overproduction of cytokines and activation of the immune system; they might be a lead cause of organ damage. However, patients with severe COVID-19 who received anticoagulant therapy had lower mortality, especially with elevated D-dimer or fibrin degradation products (FDP). In this regard, the discovery of natural products with anticoagulant potential may help mitigate the numerous side effects of the available synthetic drugs. This review sheds light on blood coagulation and its impact on the complication associated with COVID-19. Furthermore, the sources of natural anticoagulants, the role of nanoparticle formulation in this outbreak, and the prevalence of thrombosis with thrombocytopenia syndrome (TTS) after COVID-19 vaccines are also reviewed. These combined data provide many research ideas related to the possibility of using these anticoagulant agents as a treatment to relieve acute symptoms of COVID-19 infection.

Janus Kinase Signaling Pathway and Its Role in COVID-19 Inflammatory, Vascular, and Thrombotic Manifestations.

Acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection continues to be a worldwide public health crisis. Among the several severe manifestations of this disease, thrombotic processes drive the catastrophic organ failure and mortality in these patients. In addition to a well-established cytokine storm associated with the disease, perturbations in platelets, endothelial cells, and the coagulation system are key in triggering systemic coagulopathy, involving both the macro- and microvasculatures of different organs. Of the several mechanisms that might contribute to dysregulation of these cells following SARS-CoV-2 infection, the current review focuses on the role of activated Janus kinase (JAK) signaling in augmenting thrombotic processes and organ dysfunction. The review concludes with presenting the current understanding and emerging controversies concerning the potential therapeutic applications of JAK inhibitors for ameliorating the inflammation-thrombosis phenotype in COVID-19 patients.

Effect of anti-interleukin drugs in patients with COVID-19 and signs of cytokine release syndrome (COV-AID): a factorial, randomised, controlled trial.

BACKGROUND: Infections with SARS-CoV-2 continue to cause significant morbidity and mortality. Interleukin (IL)-1 and IL-6 blockade have been proposed as therapeutic strategies in COVID-19, but study outcomes have been conflicting. We sought to study whether blockade of the IL-6 or IL-1 pathway shortened the time to clinical improvement in patients with COVID-19, hypoxic respiratory failure, and signs of systemic cytokine release syndrome. METHODS: We did a prospective, multicentre, open-label, randomised, controlled trial, in hospitalised patients with COVID-19, hypoxia, and signs of a cytokine release syndrome across 16 hospitals in Belgium. Eligible patients had a proven diagnosis of COVID-19 with symptoms between 6 and 16 days, a ratio of the partial pressure of oxygen to the fraction of inspired oxygen (PaO2:FiO2) of less than 350 mm Hg on room air or less than 280 mm Hg on supplemental oxygen, and signs of a cytokine release syndrome in their serum (either a single ferritin measurement of more than 2000 µg/L and immediately requiring high flow oxygen or mechanical ventilation, or a ferritin concentration of more than 1000 µg/L, which had been increasing over the previous 24 h, or lymphopenia below 800/mL with two of the following criteria: an increasing ferritin concentration of more than 700 µg/L, an increasing lactate dehydrogenase concentration of more than 300 international units per L, an increasing C-reactive protein concentration of more than 70 mg/L, or an increasing D-dimers concentration of more than 1000 ng/mL). The COV-AID trial has a 2 × 2 factorial design to evaluate IL-1 blockade versus no IL-1 blockade and IL-6 blockade versus no IL-6 blockade. Patients were randomly assigned by means of permuted block randomisation with varying block size and stratification by centre. In a first randomisation, patients were assigned to receive subcutaneous anakinra once daily (100 mg) for 28 days or until discharge, or to receive no IL-1 blockade (1:2). In a second randomisation step, patients were allocated to receive a single dose of siltuximab (11 mg/kg) intravenously, or a single dose of tocilizumab (8 mg/kg) intravenously, or to receive no IL-6 blockade (1:1:1). The primary outcome was the time to clinical improvement, defined as time from randomisation to an increase of at least two points on a 6-category ordinal scale or to discharge from hospital alive. The primary and supportive efficacy endpoints were assessed in the intention-to-treat population. Safety was assessed in the safety population. This study is registered online with ClinicalTrials.gov (NCT04330638) and EudraCT (2020-001500-41) and is complete. FINDINGS: Between April 4, and Dec 6, 2020, 342 patients were randomly assigned to IL-1 blockade (n=112) or no IL-1 blockade (n=230) and simultaneously randomly assigned to IL-6 blockade (n=227; 114 for tocilizumab and 113 for siltuximab) or no IL-6 blockade (n=115). Most patients were male (265 [77%] of 342), median age was 65 years (IQR 54-73), and median Systematic Organ Failure Assessment (SOFA) score at randomisation was 3 (2-4). All 342 patients were included in the primary intention-to-treat analysis. The estimated median time to clinical improvement was 12 days (95% CI 10-16) in the IL-1 blockade group versus 12 days (10-15) in the no IL-1 blockade group (hazard ratio [HR] 0·94 [95% CI 0·73-1·21]). For the IL-6 blockade group, the estimated median time to clinical improvement was 11 days (95% CI 10-16) versus 12 days (11-16) in the no IL-6 blockade group (HR 1·00 [0·78-1·29]). 55 patients died during the study, but no evidence for differences in mortality between treatment groups was found. The incidence of serious adverse events and serious infections was similar across study groups. INTERPRETATION: Drugs targeting IL-1 or IL-6 did not shorten the time to clinical improvement in this sample of patients with COVID-19, hypoxic respiratory failure, low SOFA score, and low baseline mortality risk. FUNDING: Belgian Health Care Knowledge Center and VIB Grand Challenges program.

Disorders of the Cholinergic System in COVID-19 Era-A Review of the Latest Research.

The appearance of the SARS-CoV-2 virus initiated many studies on the effects of the virus on the human body. So far, its negative influence on the functioning of many morphological and physiological units, including the nervous system, has been demonstrated. Consequently, research has been conducted on the changes that SARS-CoV-2 may cause in the cholinergic system. The aim of this study is to review the latest research from the years 2020/2021 regarding disorders in the cholinergic system caused by the SARS-CoV-2 virus. As a result of the research, it was found that the presence of the COVID-19 virus disrupts the activity of the cholinergic system, for example, causing the development of myasthenia gravis or a change in acetylcholine activity. The SARS-CoV-2 spike protein has a sequence similar to neurotoxins, capable of binding nicotinic acetylcholine receptors (nAChR). This may be proof that SARS-CoV-2 can bind nAChR. Nicotine and caffeine have similar structures to antiviral drugs, capable of binding angiotensin-converting enzyme 2 (ACE 2) epitopes that are recognized by SARS-CoV-2, with the potential to inhibit the formation of the ACE 2/SARS-CoV-2 complex. The blocking is enhanced when nicotine and caffeine are used together with antiviral drugs. This is proof that nAChR agonists can be used along with antiviral drugs in COVID-19 therapy. As a result, it is possible to develop COVID-19 therapies that use these compounds to reduce cytokine production. Another promising therapy is non-invasive stimulation of the vagus nerve, which soothes the body's cytokine storm. Research on the influence of COVID-19 on the cholinergic system is an area that should continue to be developed as there is a need for further research. It can be firmly stated that COVID-19 causes a dysregulation of the cholinergic system, which leads to a need for further research, because there are many promising therapies that will prevent the SARS-CoV-2 virus from binding to the nicotinic receptor. There is a need for further research, both in vitro and in vivo. It should be noted that in the functioning of the cholinergic system and its connection with the activity of the COVID-19 virus, there might be many promising dependencies and solutions.

Neutrophil Extracellular Traps (NETs) and Covid-19: A new frontiers for therapeutic modality.

Coronavirus disease 2019 (Covid-19) is a worldwide infectious disease caused by severe acute respiratory coronavirus 2 (SARS-CoV-2). In severe SARS-CoV-2 infection, there is severe inflammatory reactions due to neutrophil recruitments and infiltration in the different organs with the formation of neutrophil extracellular traps (NETs), which involved various complications of SARS-CoV-2 infection. Therefore, the objective of the present review was to explore the potential role of NETs in the pathogenesis of SARS-CoV-2 infection and to identify the targeting drugs against NETs in Covid-19 patients. Different enzyme types are involved in the formation of NETs, such as neutrophil elastase (NE), which degrades nuclear protein and release histones, peptidyl arginine deiminase type 4 (PADA4), which releases chromosomal DNA and gasdermin D, which creates pores in the NTs cell membrane that facilitating expulsion of NT contents. Despite of the beneficial effects of NETs in controlling of invading pathogens, sustained formations of NETs during respiratory viral infections are associated with collateral tissue injury. Excessive development of NETs in SARS-CoV-2 infection is linked with the development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) due to creation of the NETs-IL-1ß loop. Also, aberrant NTs activation alone or through NETs formation may augment SARS-CoV-2-induced cytokine storm (CS) and macrophage activation syndrome (MAS) in patients with severe Covid-19. Furthermore, NETs formation in SARS-CoV-2 infection is associated with immuno-thrombosis and the development of ALI/ARDS. Therefore, anti-NETs therapy of natural or synthetic sources may mitigate SARS-CoV-2 infection-induced exaggerated immune response, hyperinflammation, immuno-thrombosis, and other complications.

Potential Role of Colchicine in Combating COVID-19 Cytokine Storm and Its Ability to Inhibit Protease Enzyme of SARS-CoV-2 as Conferred by Molecular Docking Analysis.

Despite the advance in the management of Coronavirus disease 2019 (COVID-19), the global pandemic is still ongoing with a massive health crisis. COVID-19 manifestations may range from mild symptoms to severe life threatening ones. The hallmark of the disease severity is related to the overproduction of pro-inflammatory cytokines manifested as a cytokine storm. Based on its anti-inflammatory activity through interfering with several pro and anti-inflammatory pathways, colchicine had been proposed to reduce the cytokine storm and subsequently improve clinical outcomes. Molecular docking analysis of colchicine against RNA-dependent RNA polymerase (RdRp) and protease enzymes of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) revealed that colchicine provided a grid-based molecular docking method, C-DOCKER interaction energy 64.26 and 47.53 (Kcal/mol) with protease and RdRp, respectively. This finding indicated higher binding stability for colchicine-protease complexes than the colchicine-RdRp complex with the involvement of seven hydrogen bonds, six hydrogen acceptors with Asn142, Gly143, Ser144, and Glu166 and one hydrogen-bond donors with Cys145 of the protease enzyme. This is in addition to three hydrophobic interactions with His172, Glu166, and Arg188. A good alignment with the reference compound, Boceprevir, indicated high probability of binding to the protease enzyme of SARS-CoV-2. In conclusion, colchicine can ameliorate the destructive effect of the COVID-19 cytokine storm with a strong evidence of antiviral activity by inhibiting the protease enzyme of SARS-CoV-2.

C-reactive protein as an effector molecule in Covid-19 pathogenesis.

The current pandemic caused by SARS-CoV-2 virus infection is known as Covid-19 (coronavirus disease 2019). This disease can be asymptomatic or can affect multiple organ systems. Damage induced by the virus is related to dysfunctional activity of the immune system, but the activity of molecules such as C-reactive protein (CRP) as a factor capable of inducing an inflammatory status that may be involved in the severe evolution of the disease, has not been extensively evaluated. A systematic review was performed using the NCBI-PubMed database to find articles related to Covid-19 immunity, inflammatory response, and CRP published from December 2019 to December 2020. High levels of CRP were found in patients with severe evolution of Covid-19 in which several organ systems were affected and in patients who died. CRP activates complement, induces the production of pro-inflammatory cytokines and induces apoptosis which, together with the inflammatory status during the disease, can lead to a severe outcome. Several drugs can decrease the level or block the effect of CRP and might be useful in the treatment of Covid-19. From this review it is reasonable to conclude that CRP is a factor that can contribute to severe evolution of Covid-19 and that the use of drugs able to lower CRP levels or block its activity should be evaluated in randomized controlled clinical trials.