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.

[The neurology of COVID-19]. / La neurología de COVID-19.

The clinical manifestations of COVID-19 are reminiscent of those of acute respiratory distress syndrome induced by cytokine release syndrome and secondary hemophagocytic lymphohistiocytosis that is observed in patients with other coronaviruses such as SARS-CoV and MERS-CoV. Neurologists face the challenge of assessing patients with pre-existing neurological diseases who have contracted SARS-CoV-2, patients with COVID-19 who present neurological emergencies, and patients who are carriers of the virus and have developed secondary neurological complications, either during the course of the disease or after it. Some authors and recent literature reports suggest that the presence of neurological manifestations in patients who are carriers of SARS-CoV-2 may be associated with a greater severity of the disease.

Las manifestaciones clínicas de COVID-19 recuerdan las del síndrome de insuficiencia respiratoria aguda inducido por el síndrome de liberación de citocinas y la linfohistiocitosis hemofagocitica observada en pacientes con otros coronavirus como SARS-CoV y MERS-CoV. Los neurólogos tienen el reto de evaluar pacientes con enfermedades neurológicas preexistentes que contraen SARS-CoV-2, pacientes con COVID-19 que presentan emergencias neurológicas y pacientes portadores del virus que desarrollan complicaciones neurológicas secundarias, durante el curso de la enfermedad o posterior a la misma. Algunos autores y reportes en la literatura recientes sugieren que las manifestaciones neurológicas en pacientes portadores de SARS-CoV-2 pueden asociarse con mayor gravedad de la enfermedad.

Inflammatory neuropsychiatric disorders and COVID-19 neuroinflammation.

Neuropsychiatric sequalae to coronavirus disease 2019 (COVID-19) infection are beginning to emerge, like previous Spanish influenza and severe acute respiratory syndrome episodes. Streptococcal infection in paediatric patients causing obsessive compulsive disorder (PANDAS) is another recent example of an infection-based psychiatric disorder. Inflammation associated with neuropsychiatric disorders has been previously reported but there is no standard clinical management approach established. Part of the reason is that it is unclear what factors determine the specific neuronal vulnerability and the efficacy of anti-inflammatory treatment in neuroinflammation. The emerging COVID-19 data suggested that in the acute stage, widespread neuronal damage appears to be the result of abnormal and overactive immune responses and cytokine storm is associated with poor prognosis. It is still too early to know if there are long-term-specific neuronal or brain regional damages associated with COVID-19, resulting in distinct neuropsychiatric disorders. In several major psychiatric disorders where neuroinflammation is present, patients with abnormal inflammatory markers may also experience less than favourable response or treatment resistance when standard treatment is used alone. Evidence regarding the benefits of co-administered anti-inflammatory agents such as COX-2 inhibitor is encouraging in selected patients though may not benefit others. Disease-modifying therapies are increasingly being applied to neuropsychiatric diseases characterised by abnormal or hyperreactive immune responses. Adjunct anti-inflammatory treatment may benefit selected patients and is definitely an important component of clinical management in the presence of neuroinflammation.

Down Syndrome and COVID-19: A Perfect Storm?

People with Down syndrome show signs of chronic immune dysregulation, including a higher prevalence of autoimmune disorders, increased rates of hospitalization during respiratory viral infections, and higher mortality rates from pneumonia and sepsis. At the molecular and cellular levels, they show markers of chronic autoinflammation, including interferon hyperactivity, elevated levels of many inflammatory cytokines and chemokines, and changes in diverse immune cell types reminiscent of inflammatory conditions observed in the general population. However, the impact of this immune dysregulation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and CoV disease of 2019 (COVID-19) remains unknown. This Perspective outlines why individuals with Down syndrome should be considered an at-risk population for severe COVID-19. Specifically, the immune dysregulation caused by trisomy 21 may result in an exacerbated cytokine release syndrome relative to that observed in the euploid population, thus justifying additional monitoring and specialized care for this vulnerable population.

Progress and Challenges Toward Generation and Maintenance of Long-Lived Memory T Lymphocyte Responses During COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the coronavirus disease 2019 (COVID-19) pandemic is a serious global threat until we identify the effective preventive and therapeutic strategies. SARS-CoV-2 infection is characterized by various immunopathological consequences including lymphocyte activation and dysfunction, lymphopenia, cytokine storm, increased level of neutrophils, and depletion and exhaustion of lymphocytes. Considering the low level of antibody-mediated protection during coronavirus infection, understanding the role of T cell for long-term protection is decisive. Both CD4+ and CD8+ T cell response is imperative for cell-mediated immune response during COVID-19. However, the level of CD8+ T cell response reduced to almost half as compared to CD4+ after 6 months of infection. The long-term protection is mediated via generation of immunological memory response during COVID-19. The presence of memory CD4+ T cells in all the severely infected and recovered individuals shows that the memory response is predominated by CD4+ T cells. Prominently, the antigen-specific CD4+ and CD8+ T cells are specifically observed during day 0 to day 28 in COVID-19-vaccinated individuals. However, level of antigen-specific T memory cells in COVID-19-vaccinated individuals defines the long-term protection against forthcoming outbreaks of SARS-CoV-2.

Are we facing a crashing wave of neuropsychiatric sequelae of COVID-19? Neuropsychiatric symptoms and potential immunologic mechanisms.

The coronavirus disease 19 (COVID-19) pandemic is a significant psychological stressor in addition to its tremendous impact on every facet of individuals' lives and organizations in virtually all social and economic sectors worldwide. Fear of illness and uncertainty about the future precipitate anxiety- and stress-related disorders, and several groups have rightfully called for the creation and dissemination of robust mental health screening and treatment programs for the general public and front-line healthcare workers. However, in addition to pandemic-associated psychological distress, the direct effects of the virus itself (several acute respiratory syndrome coronavirus; SARS-CoV-2), and the subsequent host immunologic response, on the human central nervous system (CNS) and related outcomes are unknown. We discuss currently available evidence of COVID-19 related neuropsychiatric sequelae while drawing parallels to past viral pandemic-related outcomes. Past pandemics have demonstrated that diverse types of neuropsychiatric symptoms, such as encephalopathy, mood changes, psychosis, neuromuscular dysfunction, or demyelinating processes, may accompany acute viral infection, or may follow infection by weeks, months, or longer in recovered patients. The potential mechanisms are also discussed, including viral and immunological underpinnings. Therefore, prospective neuropsychiatric monitoring of individuals exposed to SARS-CoV-2 at various points in the life course, as well as their neuroimmune status, are needed to fully understand the long-term impact of COVID-19, and to establish a framework for integrating psychoneuroimmunology into epidemiologic studies of pandemics.

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.

The therapeutic potential of regulatory T cells in reducing cardiovascular complications in patients with severe COVID-19.

The SARS coronavirus 2 (SARS CoV-2) causes Coronavirus Disease (COVID-19), is an emerging viral infection. SARS CoV-2 infects target cells by attaching to Angiotensin-Converting Enzyme (ACE2). SARS CoV-2 could cause cardiac damage in patients with severe COVID-19, as ACE2 is expressed in cardiac cells, including cardiomyocytes, pericytes, and fibroblasts, and coronavirus could directly infect these cells. Cardiovascular disorders are the most frequent comorbidity found in COVID-19 patients. Immune cells such as monocytes, macrophages, and T cells may produce inflammatory cytokines and chemokines that contribute to COVID-19 pathogenesis if their functions are uncontrolled. This causes a cytokine storm in COVID-19 patients, which has been associated with cardiac damage. Tregs are a subset of immune cells that regulate immune and inflammatory responses. Tregs suppress inflammation and improve cardiovascular function through a variety of mechanisms. This is an exciting research area to explore the cellular, molecular, and immunological mechanisms related to reducing risks of cardiovascular complications in severe COVID-19. This review evaluated whether Tregs can affect COVID-19-related cardiovascular complications, as well as the mechanisms through which Tregs act.

Cytokine storm in COVID-19: from viral infection to immune responses, diagnosis and therapy.

The COVID-19 outbreak is emerging as a significant public health challenge. Excessive production of proinflammatory cytokines, also known as cytokine storm, is a severe clinical syndrome known to develop as a complication of infectious or inflammatory diseases. Clinical evidence suggests that the occurrence of cytokine storm in severe acute respiratory syndrome secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is closely associated with the rapid deterioration and high mortality of severe cases. In this review, we aim to summarize the mechanism of SARS-CoV-2 infection and the subsequent immunological events related to excessive cytokine production and inflammatory responses associated with ACE2-AngII signaling. An overview of the diagnosis and an update on current therapeutic regimens and vaccinations is also provided.

In Silico Studies on Psilocybin Drug Derivatives Against SARS-CoV-2 and Cytokine Storm of Human Interleukin-6 Receptor.

Various metabolites identified with therapeutic mushrooms have been found from different sources and are known to have antibacterial, antiviral, and anticancer properties. Over thousands soil growth-based mushroom metabolites have been discovered, and utilized worldwide to combat malignancy. In this study, psilocybin-mushroom that contains the psychedelic compounds such as psilacetin, psilocin, and psilocybine were screened and found to be inhibitors of SARS-CoV-2 Mprotease. It has been found that psilacetin, psilocin, and psilocybine bind to Mprotease with -6.0, -5.4, and -5.8 kcal/mol, respectively. Additionally, the psilacetin was found to inhibit human interleukin-6 receptors to reduce cytokine storm. The binding of psilacetin to Mprotease of SARS-CoV-2 and human interleukin-6 receptors changes the structural dynamics and Gibbs free energy patterns of proteins. These results suggested that psilocybin-mushroom could be utilized as viable potential chemotherapeutic agents for SARS-CoV-2.

Induction of Innate Immune Response by TLR3 Agonist Protects Mice against SARS-CoV-2 Infection.

SARS-CoV-2, a member of the coronavirus family, is the causative agent of the COVID-19 pandemic. Currently, there is still an urgent need in developing an efficient therapeutic intervention. In this study, we aimed at evaluating the therapeutic effect of a single intranasal treatment of the TLR3/MDA5 synthetic agonist Poly(I:C) against a lethal dose of SARS-CoV-2 in K18-hACE2 transgenic mice. We demonstrate here that early Poly(I:C) treatment acts synergistically with SARS-CoV-2 to induce an intense, immediate and transient upregulation of innate immunity-related genes in lungs. This effect is accompanied by viral load reduction, lung and brain cytokine storms prevention and increased levels of macrophages and NK cells, resulting in 83% mice survival, concomitantly with long-term immunization. Thus, priming the lung innate immunity by Poly(I:C) or alike may provide an immediate, efficient and safe protective measure against SARS-CoV-2 infection.

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.

Levamisole Therapy in COVID-19.

Coronavirus disease 2019 (COVID-19) a global infectious disease caused by severe acute respiratory coronavirus 2 (SARS-CoV-2) affects various organs, primarily the respiratory system, and presented with pulmonary manifestations such as acute lung injury (ALI) and acute respiratory distress syndrome. Levamisole (LVM) is an anthelminthic drug; it has immune-modulating effects through induction of type 1 immune response. Based on these findings several recent studies highlighted that LVM might be effective in preventing and treating SARS-CoV-2 infections. The aim of this report is to illustrate the potential role of LVM in SARS-CoV-2 infection and in the management of COVID-19. Different studies proposed that LVM may inhibit proliferation of SARS-CoV-2 through inhibition of papain-like protease. LVM may prevent ALI and acute kidney injury through activation of glucocorticoid receptors. In general, LVM has strong immune stimulant effects by modulating cellular and humoral immune responses. This effect is beneficial in the early phase of COVID-19 and harmful in the late phase. In the early phase, immune stimulation facilitates SARS-CoV-2 clearance and tissue repair, however, in the late phase, immune stimulation in COVID-19 may increase propagation risk of cytokine storm. In conclusion, LVM therapy in COVID-19 has bidirectional effects, beneficial in the early phase and harmful effects in the late phase of COVID-19. Clinical trial and prospective studies are warranted in this regard to confirm the efficacy and timing administration of LVM in the management of COVID-19.

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.