p38 MAPK inhibition: A promising therapeutic approach for COVID-19

Papaverine Targets STAT Signaling: A Dual-Action Therapy Option Against SARS-CoV-2

Papaverine (PV) has been previously identified as a promising candidate in SARS-CoV-2 repurposing screens. In this study, we further investigated both its antiviral and immunomodulatory properties. PV displayed antiviral efficacy against SARS-CoV-2 and influenza A viruses H1N1 and H5N1 in single infection as well as in co-infection. We demonstrated PV's activity against various SARS-CoV-2 variants and identified its action at the post-entry stage of the viral life cycle. Notably, treatment of air-liquid interface (ALI) cultures of primary bronchial epithelial cells with PV significantly inhibited SARS-CoV-2 levels. Additionally, PV was found to attenuate interferon (IFN) signaling independently of viral infection. Mechanistically, PV decreased the activation of the IFN-stimulated response element following stimulation with all three IFN types by suppressing STAT1 and STAT2 phosphorylation and nuclear translocation. Furthermore, the combination of PV with approved COVID-19 therapeutics molnupiravir and remdesivir demonstrated synergistic effects. Given its immunomodulatory effects and clinical availability, PV shows promising potential as a component for combination therapy against COVID-19.

Thromboembolic Events in the Era of COVID-19: A Detailed Narrative Review

COVID-19, caused by the SARS-CoV-2 virus, is not only characterized by respiratory symptoms but is also associated with a wide range of systemic complications, including significant hematologic abnormalities. This is a comprehensive review of the current literature, using PubMed and Google Scholar, on the pathophysiology and incidence of thromboembolic events in COVID-19 patients and thromboprophylaxis. COVID-19 infection induces a prothrombotic state in patients through the dysregulation of the renin-angiotensin-aldosterone system (RAAS), endothelial dysfunction, elevated von Willebrand factor (vWF), and a dysregulated immune response involving the complement system and neutrophil extracellular traps (NETs). As a result, thromboembolic complications have emerged in COVID-19 cases, occurring more frequently in severe cases and hospitalized patients. These thrombotic events affect both venous and arterial circulation, with increased incidences of deep venous thrombosis (DVT), pulmonary embolism (PE), systemic arterial thrombosis, and myocardial infarction (MI). While DVT and PE are more common, the literature highlights the potential lethal consequences of arterial thromboembolism (ATE). This review also briefly examines the ongoing discussions regarding the use of anticoagulants for the prevention of thrombotic events in COVID-19 patients. While theoretically promising, current studies have yielded varied outcomes: Some suggest potential benefits, whereas others report an increased risk of bleeding events among hospitalized patients. Therefore, further large-scale studies are needed to assess the efficacy and safety of anticoagulants for thromboprophylaxis in COVID-19 patients.

Investigating the Interplay Between the Nrf2/Keap1/HO-1/SIRT-1 Pathway and the p75NTR/PI3K/Akt/MAPK Cascade in Neurological Disorders: Mechanistic Insights and Therapeutic Innovations

Neurological illnesses are debilitating diseases that affect brain function and balance. Due to their complicated aetiologies and progressive nature, neurodegenerative and neuropsychiatric illnesses are difficult to treat. These incurable conditions damage brain functions like mobility, cognition, and emotional regulation, but medication, gene therapy, and physical therapy can manage symptoms. Disruptions in cellular signalling pathways, especially those involving oxidative stress response, memory processing, and neurotransmitter modulation, contribute to these illnesses. This review stresses the interplay between key signalling pathways involved in neurological diseases, such as the Nrf2/Keap1/HO-1/SIRT-1 axis and the p75NTR/PI3K/Akt/MAPK cascade. To protect neurons from oxidative damage and death, the Nrf2 transcription factor promotes antioxidant enzyme production. The Keap1 protein releases Nrf2 during oxidative stress for nuclear translocation and gene activation. The review also discusses how neurotrophin signalling through the p75 neurotrophin receptor (p75NTR) determines cell destiny, whether pro-survival or apoptotic. The article highlights emerging treatment approaches targeting these signalling pathways by mapping these connections. Continued research into these molecular pathways may lead to new neurological disease treatments that restore cellular function and neuronal survival. In addition to enhanced delivery technologies, specific modulators and combination therapies should be developed to fine-tune signalling responses. Understanding these crosstalk dynamics is crucial to strengthening neurological illness treatment options and quality of life.

Binding mechanism of inhibitors to DFG-in and DFG-out P38α deciphered using multiple independent Gaussian accelerated molecular dynamics simulations and deep learning

P38α has been identified as a key target for drug design to treat a wide range of diseases. In this study, multiple independent Gaussian accelerated molecular dynamics (GaMD) simulations, deep learning (DL), and the molecular mechanics generalized Born surface area (MM-GBSA) method were used to investigate the binding mechanism of inhibitors (SB2, SK8, and BMU) to DFG-in and DFG-out P38α and clarify the effect of conformational differences in P38α on inhibitor binding. GaMD trajectory-based DL effectively identified important functional domains, such as the A-loop and N-sheet. Post-processing analysis on GaMD trajectories showed that binding of the three inhibitors profoundly affected the structural flexibility and dynamical behaviour of P38α situated at the DFG-in and DFG-out states. The MM-GBSA calculations not only revealed that differences in the binding ability of inhibitors are affected by DFG-in and DFG-out conformations of P38α, but also confirmed that van der Waals interactions are the primary force driving inhibitor-P38α binding. Residue-based free energy estimation identifies hot spots of inhibitor-P38α binding across DFG-in and DFG-out conformations, providing potential target sites for drug design towards P38α. This work is expected to offer valuable theoretical support for the development of selective inhibitors of P38α family members.

Rethinking Optimal Immunogens to Face SARS-CoV-2 Evolution Through Vaccination

SARS-CoV-2, which originated in China in late 2019, quickly fueled the global COVID-19 pandemic, profoundly impacting health and the economy worldwide. A series of vaccines, mostly based on the full SARS-CoV-2 Spike protein, were rapidly developed, showing excellent humoral and cellular responses and high efficacy against both symptomatic infection and severe disease. However, viral evolution and the waning humoral neutralizing responses strongly challenged vaccine long term effectiveness, mainly against symptomatic infection, making necessary a strategy of repeated and updated booster shots. In this repeated vaccination context, antibody repertoire diversification was evidenced, although immune imprinting after booster doses or reinfection was also demonstrated and identified as a major determinant of immunological responses to repeated antigen exposures. Considering that a small domain of the SARS-CoV-2 Spike protein, the receptor binding domain (RBD), is the major target of neutralizing antibodies and concentrates most viral mutations, the following text aims to provide insights into the ongoing debate over the best strategies for vaccine boosters. We address the relevance of developing new booster vaccines that target the evolving RBD, thus focusing on the relevant antigenic sites of the SARS-CoV-2 new variants. A combination of this strategy with immunofusing and computerized approaches could minimize immune imprinting, therefore optimizing neutralizing immune responses and booster vaccine efficacy.

Linking COVID-19 and cancer: Underlying mechanism

COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), lead to a global health crisis with a spectrum of clinical manifestations. A potentially vulnerable category for SARS-CoV-2 infection was identified in patients with other medical conditions. Intriguingly, parallels exist between COVID-19 and cancer at the pathophysiological level, suggesting a possible connection between them. This review discusses all possible associations between COVID-19 and cancer. Expression of receptors like angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) increases COVID-19 susceptibility. SARS-CoV-2 infection might increase cancer susceptibility and accelerate cancer progression through mechanisms involving cytokine storm, tissue hypoxia, impaired T-cell responses, autophagy, neutrophil activation, and oxidative stress. These mechanisms collectively contribute to immune suppression, hindered apoptosis, and altered cellular signaling in the tumor microenvironment, creating conditions favorable for tumor growth, metastasis, and recurrence. Approved vaccines and their impact on cancer patients along-with new clinical trials are also described.

Targeting Ser78 phosphorylation of Hsp27 achieves potent antiviral effects against enterovirus A71 infection

A positive-sense (+) single-stranded RNA (ssRNA) virus (e.g. enterovirus A71, EV-A71) depends on viral polypeptide translation for initiation of virus replication after entry. We reported that EV-A71 hijacks Hsp27 to induce hnRNP A1 cytosol redistribution to initiate viral protein translation, but the underlying mechanism is still elusive. Here, we show that phosphorylation-deficient Hsp27-3A (Hsp27S15/78/82A) and Hsp27S78A fail to translocate into the nucleus and induce hnRNP A1 cytosol redistribution, while Hsp27S15A and Hsp27S82A display similar effects to the wild type Hsp27. Furthermore, we demonstrate that the viral 2A protease (2Apro) activity is a key factor in regulating Hsp27/hnRNP A1 relocalization. Hsp27S78A dramatically decreases the IRES activity and viral replication, which are partially reduced by Hsp27S82A. However, Hsp27S15A displays the same activity as the wild-type Hsp27. Peptide S78 potently suppresses EV-A71 protein translation and reproduction through blockage of EV-A71-induced Hsp27 phosphorylation and Hsp27/hnRNP A1 relocalization. A point mutation (S78A) on S78 impairs its inhibitory functions on Hsp27/hnRNP A1 relocalization and viral replication. Taken together, we demonstrate the importance of Ser78 phosphorylation of Hsp27 regulated by virus infection in nuclear translocation, hnRNP A1 cytosol relocation, and viral replication, suggesting a new path (such as peptide S78) for target-based antiviral strategy.

Prostaglandins and non-steroidal anti-inflammatory drugs in Covid-19

In response to different viral infections, including SARS-CoV-2 infection, pro-inflammatory, anti-inflammatory cytokines, and bioactive lipids are released from infected and immune cells. One of the most critical bioactive lipids is prostaglandins (PGs) which favor perseverance of inflammation leading to chronic inflammation as PGs act as cytokine amplifiers. PGs trigger the release of pro-inflammatory cytokines, activate Th cells, recruit immune cells, and increase the expression of pro-inflammatory genes. Therefore, PGs may induce acute and chronic inflammations in various inflammatory disorders and viral infections like SARS-CoV-2. PGs are mainly inhibited by non-steroidal anti-inflammatory drugs (NSAIDs) by blocking cyclooxygenase enzymes (COXs), which involve PG synthesis. NSAIDs reduce inflammation by selective or non-selective blocking activity of COX2 or COX1/2, respectively. In the Covid-19 era, there is a tremendous controversy regarding the use of NSAIDs in the management of SARS-CoV-2 infection. As well, the possible role of PGs in the pathogenesis of SARS-CoV-2 infection is not well-defined. Thus, the objective of the present study is to review the potential role of PGs and NSAIDs in Covid-19 in a narrative review regarding the preponderance of assorted views.

Three modes of viral adaption by the heart

Viruses elicit long-term adaptive responses in the tissues they infect. Understanding viral adaptions in humans is difficult in organs such as the heart, where primary infected material is not routinely collected. In search of asymptomatic infections with accompanying host adaptions, we mined for cardio-pathogenic viruses in the unaligned reads of nearly 1000 human hearts profiled by RNA sequencing. Among virus-positive cases (~20%), we identified three robust adaptions in the host transcriptome related to inflammatory nuclear factor κB (NF-κB) signaling and posttranscriptional regulation by the p38-MK2 pathway. The adaptions are not determined by the infecting virus, and they recur in infections of human or animal hearts and cultured cardiomyocytes. Adaptions switch states when NF-κB or p38-MK2 is perturbed in cells engineered for chronic infection by the cardio-pathogenic virus, coxsackievirus B3. Stratifying viral responses into reversible adaptions adds a targetable systems-level simplification for infections of the heart and perhaps other organs.

Spatiotemporal control of kinases and the biomolecular tools to trace activity

The delicate balance of cell physiology is implicitly tied to the expression and activation of proteins. Post-translational modifications offer a tool to dynamically switch protein activity on and off to orchestrate a wide range of protein-protein interactions to tune signal transduction during cellular homeostasis and pathological responses. There is a growing acknowledgment that subcellular locations of kinases define the spatial network of potential scaffolds, adaptors, and substrates. These highly ordered and localized biomolecular microdomains confer a spatially distinct bias in the outcomes of kinase activity. Furthermore, they may hold essential clues to the underlying mechanisms that promote disease. Developing tools to dissect the spatiotemporal activation of kinases is critical to reveal these mechanisms and promote the development of spatially targeted kinase inhibitors. Here, we discuss the spatial regulation of kinases, the tools used to detect their activity, and their potential impact on human health.

Role for IRAK-4 and p38 in Neutrophil Signaling in Response to Bacterial Lipoproteins from Staphylococcus aureus

Neutrophils, polymorphonuclear leukocytes (PMN), express numerous pattern recognition receptors, including TLRs, capable of recognizing a wide variety of pathogens. Receptor engagement initiates a cascade of PMN responses with some occurring in seconds, and some requiring de novo protein synthesis over the course of many hours. Although numerous species of bacteria and bacterial products have been shown to activate PMN via TLRs, the signaling intermediates required for distinct PMN responses have not been well-defined in human PMN. Given the potential for host tissue damage by overexuberant PMN activity, a better understanding of neutrophil signaling is needed to generate effective therapies. We hypothesized that PMN responses to a lipoprotein-containing cell membrane preparation from methicillin-resistant S. aureus (MRSA-CMP) would activate signaling via IRAK4 and p38, with potentially distinct pathways for early vs. late responses. Using human PMN we investigated MRSA-CMP-elicited reactive oxygen species (ROS) production, elastase activity, NET formation, IL-8 production, and the role of IRAK4 and p38 activation. MRSA-CMP elicited ROS in a concentration and lipoprotein-dependent manner. MRSA-CMP elicited phosphorylation of p38 MAPK, and MRSA-CMP-elicited ROS production was partially dependent on p38 MAPK and IRAK4 activation. Inhibition of IRAK4 resulted in a reduction of p38 phosphorylation. MRSA-CMP-elicited elastase activity and NET formation was partially dependent on p38 MAPK activation, but independent of IRAK4 activation. MRSA-CMP-elicited IL-8 production required both p38 and IRAK4 activation. In conclusion, MRSA-CMP elicits PMN responses via distinct signaling pathways. There is potential to target components of the neutrophil inflammatory response without compromising critical pathogen-specific immune functions.

A deep learning drug screening framework for integrating local-global characteristics: A novel attempt for limited data

At the beginning of the "Disease X" outbreak, drug discovery and development are often challenged by insufficient and unbalanced data. To address this problem and maximize the information value of limited data, we propose a drug screening model, LGCNN, based on convolutional neural network (CNN), which enables rapid drug screening by integrating features of drug molecular structures and drug-target interactions at both local and global (LG) levels. Experimental results show that LGCNN exhibits better performance compared to other state-of-the-art classification methods under limited data. In addition, LGCNN was applied to anti-SARS-CoV-2 drug screening to realize therapeutic drug mining against COVID-19. LGCNN transcends the limitations of traditional models for predicting interactions between single drug targets and shows new advantages in predicting multi-target drug-target interactions. Notably, the cross-coronavirus generalizability of the model is also implied by the analysis of targets, drugs, and mechanisms in the prediction results. In conclusion, LGCNN provides new ideas and methods for rapid drug screening in emergency situations where data are scarce.

Taming the storm: potential anti-inflammatory compounds targeting SARS-CoV-2 MPro

In severe COVID-19 cases, an exacerbated inflammatory response triggers a cytokine storm that can worsen the prognosis. Compounds with both antiviral and anti-inflammatory activities show promise as candidates for COVID-19 therapy, as they potentially act against the SARS-CoV-2 infection regardless of the disease stage. One of the most attractive drug targets among coronaviruses is the main protease (MPro). This enzyme is crucial for cleaving polyproteins into non-structural proteins required for viral replication. The aim of this review was to identify SARS-CoV-2 MPro inhibitors with both antiviral and anti-inflammatory properties. The interactions of the compounds within the SARS-CoV-2 MPro binding site were analyzed through molecular docking when data from crystallographic structures were unavailable. 18 compounds were selected and classified into five different superclasses. Five of them exhibit high potency against MPro: GC-376, baicalein, naringenin, heparin, and carmofur, with IC50 values below 0.2 μM. The MPro inhibitors selected have the potential to alleviate lung edema and decrease cytokine release. These molecules mainly target three critical inflammatory pathways: NF-κB, JAK/STAT, and MAPK, all previously associated with COVID-19 pathogenesis. The structures of the compounds occupy the S1/S2 substrate binding subsite of the MPro. They interact with residues from the catalytic dyad (His41 and Cys145) and/or with the oxyanion hole (Gly143, Ser144, and Cys145), which are pivotal for substrate recognition. The MPro SARS-CoV-2 inhibitors with potential anti-inflammatory activities present here could be optimized for maximum efficacy and safety and be explored as potential treatment of both mild and severe COVID-19.

Immunobiology of COVID-19: Mechanistic and therapeutic insights from animal models

The distribution of the immune system throughout the body complicates in vitro assessments of coronavirus disease 2019 (COVID-19) immunobiology, often resulting in a lack of reproducibility when extrapolated to the whole organism. Consequently, developing animal models is imperative for a comprehensive understanding of the pathology and immunology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This review summarizes current progress related to COVID-19 animal models, including non-human primates (NHPs), mice, and hamsters, with a focus on their roles in exploring the mechanisms of immunopathology, immune protection, and long-term effects of SARS-CoV-2 infection, as well as their application in immunoprevention and immunotherapy of SARS-CoV-2 infection. Differences among these animal models and their specific applications are also highlighted, as no single model can fully encapsulate all aspects of COVID-19. To effectively address the challenges posed by COVID-19, it is essential to select appropriate animal models that can accurately replicate both fatal and non-fatal infections with varying courses and severities. Optimizing animal model libraries and associated research tools is key to resolving the global COVID-19 pandemic, serving as a robust resource for future emerging infectious diseases.

Cytokine Storm in COVID-19: Insight into Pathological Mechanisms and Therapeutic Benefits of Chinese Herbal Medicines

Cytokine storm (CS) is the main driver of SARS-CoV-2-induced acute respiratory distress syndrome (ARDS) in severe coronavirus disease-19 (COVID-19). The pathological mechanisms of CS are quite complex and involve multiple critical molecular targets that turn self-limited and mild COVID-19 into a severe and life-threatening concern. At present, vaccines are strongly recommended as safe and effective treatments for preventing serious illness or death from COVID-19. However, effective treatment options are still lacking for people who are at the most risk or hospitalized with severe disease. Chinese herbal medicines have been shown to improve the clinical outcomes of mild to severe COVID-19 as an adjunct therapy, particular preventing the development of mild to severe ARDS. This review illustrates in detail the pathogenesis of CS-involved ARDS and its associated key molecular targets, cytokines and signalling pathways. The therapeutic targets were identified particularly in relation to the turning points of the development of COVID-19, from mild symptoms to severe ARDS. Preclinical and clinical studies were reviewed for the effects of Chinese herbal medicines together with conventional therapies in reducing ARDS symptoms and addressing critical therapeutic targets associated with CS. Multiple herbal formulations, herbal extracts and single bioactive phytochemicals with or without conventional therapies demonstrated strong anti-CS effects through multiple mechanisms. However, evidence from larger, well-designed clinical trials is lacking and their detailed mechanisms of action are yet to be well elucidated. More research is warranted to further evaluate the therapeutic value of Chinese herbal medicine for CS in COVID-19-induced ARDS.

Spatial immune landscapes of SARS-CoV-2 gastrointestinal infection: macrophages contribute to local tissue inflammation and gastrointestinal symptoms

Background

In some patients, persistent gastrointestinal symptoms like abdominal pain, nausea, and diarrhea occur as part of long COVID-19 syndrome following acute respiratory symptoms caused by SARS-CoV-2. However, the characteristics of immune cells in the gastrointestinal tract of COVID-19 patients and their association with these symptoms remain unclear.

Methodology

Data were collected from 95 COVID-19 patients. Among this cohort, 11 patients who exhibited gastrointestinal symptoms and underwent gastroscopy were selected. Using imaging mass cytometry, the gastrointestinal tissues of these patients were thoroughly analyzed to identify immune cell subgroups and investigate their spatial distribution.

Results

Significant acute inflammatory responses were found in the gastrointestinal tissues, particularly in the duodenum, of COVID-19 patients. These alterations included an increase in the levels of CD68+ macrophages and CD3+CD4+ T-cells, which was more pronounced in tissues with nucleocapsid protein (NP). The amount of CD68+ macrophages positively correlates with the number of CD3+CD4+ T-cells (R = 0.783, p < 0.001), additionally, spatial neighborhood analysis uncovered decreased interactions between CD68+ macrophages and multiple immune cells were noted in NP-positive tissues. Furthermore, weighted gene coexpression network analysis was employed to extract gene signatures related to clinical features and immune responses from the RNA-seq data derived from gastrointestinal tissues from COVID-19 patients, and we validated that the MEgreen module shown positive correlation with clinical parameter (i.e., Total bilirubin, ALT, AST) and macrophages (R = 0.84, p = 0.001), but negatively correlated with CD4+ T cells (R = -0.62, p = 0.004). By contrast, the MEblue module was inversely associated with macrophages and positively related with CD4+ T cells. Gene function enrichment analyses revealed that the MEgreen module is closely associated with biological processes such as immune response activation, signal transduction, and chemotaxis regulation, indicating its role in the gastrointestinal inflammatory response.

Conclusion

The findings of this study highlight the role of specific immune cell groups in the gastrointestinal inflammatory response in COVID-19 patients. Gene coexpression network analysis further emphasized the importance of the gene modules in gastrointestinal immune responses, providing potential molecular targets for the treatment of COVID-19-related gastrointestinal symptoms.

A mini-review of the anti-SARS-CoV-2 potency of Amaryllidaceae alkaloids

BACKGROUND

Nature has perennially served as an infinite reservoir of diverse chemicals with numerous applications benefiting humankind. In recent years, due to the emerging COVID-19 pandemic, there has been a surge in studies on repurposing natural products as anti-SARS-CoV-2 agents, including plant-derived substances. Among all types of natural products, alkaloids remain one of the most important groups with various known medicinal values. The current investigation focuses on Amaryllidaceae alkaloids (AAs) since AAs have drawn significant scientific attention as anti-SARS-CoV-2 agents over the past few years.

PURPOSE AND STUDY DESIGN

This study serves as a mini-review, summarizing recent advances in studying the anti-SARS-CoV-2 potency of AAs, covering two aspects: structure-activity relationship and mechanism of action (MOA).

METHODS

The study covers the period from 2019 to 2023. The information in this review were retrieved from common databases including Web of Science, ScienceDirect, PubMed and Google scholar. Reported anti-SARS-CoV-2 potency, cytotoxicity and possible biological targets of AAs were summarized and classified into different skeletal subclasses. Then, the structure-activity relationship (SAR) was explored, pinpointing the key pharmacophore-related structural moieties. To study the mechanism of action of anti-SARS-CoV-2 AAs, possible biological targets were discussed.

RESULTS

In total, fourteen research articles about anti-SARS-CoV-2 was selected. From the SAR point of view, four skeletal subclasses of AAs (lycorine-, galanthamine-, crinine- and homolycorine-types) appear to be promising for further investigation as anti-SARS-CoV-2 agents despite experimental inconsistencies in determining in vitro half maximal inhibitory effective concentration (EC50). Narciclasine, haemanthamine- and montanine-type skeletons were cytotoxic and devoid of anti-SARS-CoV-2 activity. The lycorine-type scaffold was the most structurally diverse in this study and preliminary structure-activity relationships revealed the crucial role of ring C and substituents on rings A, C and D in its anti-SARS-CoV-2 activity. It also appears that two enantiomeric skeletons (haemanthamine- and crinine-types) displayed opposite activity/toxicity profiles regarding anti-SARS-CoV-2 activity. Pharmacophore-related moieties of the haemanthamine/crinine-type skeletons were the substituents on rings B, C and the dioxymethylene moiety. All galanthamine-type alkaloids in this study were devoid of cytotoxicity and it appears that varying substituents on rings C and D could enhance the anti-SARS-CoV-2 potency. Regarding MOAs, initial experimental results suggested Mpro and RdRp as possible viral targets. Dual functionality between anti-inflammatory activity on host cells and anti-SARS-CoV-2 activity on the SARS-CoV-2 virus of isoquinoline alkaloids, including AAs, were suggested as the possible MOAs to alleviate severe complications in COVID-19 patients. This dual functionality was proposed to be related to the p38 MAPK signaling pathway.

CONCLUSION

Overall, Amaryllidaceae alkaloids appear to be promising for further investigation as anti-SARS-CoV-2 agents. The skeletal subclasses holding the premise for further investigation are lycorine-, crinine-, galanthamine- and homolycorine-types.

CNS-Active p38α MAPK Inhibitors for the Management of Neuroinflammatory Diseases: Medicinal Chemical Properties and Therapeutic Capabilities

During the last two decades, many p38α mitogen-activated protein kinase (p38α MAPK) inhibitors have been developed and tested in preclinical/clinical studies for the treatment of various disorders, especially problems with the origin of inflammation. Previous studies strongly suggest the involvement of the p38α MAPK pathway in the pathogenesis of neurodegenerative disorders. Despite the significant progress made in this field, so far no studies have focused on p38α MAPK inhibitors that have the capability to be used for the treatment of neurodegenerative disorders. In the present review, we evaluated a wide range of well-known p38α MAPK inhibitors (more than 140 small molecules) by measuring key physicochemical parameters to identify those capable of successfully crossing the blood-brain barrier (BBB). As a result, we identify about 50 naturally occurring and synthetic p38α MAPK inhibitors with high potential to cross the BBB, which can be further explored in the future for the treatment of neurodegenerative disorders. In addition, a detailed analysis of the previously released X-ray crystal structure of the inhibitors in the active site of the p38α MAPK enzyme revealed that some residues such as Met109 play a critical role in the occurrence of effective interactions by constructing strong H-bonds. This study can encourage scientists to focus more on the design, production, and biological evaluation of new central nervous system (CNS)-active p38α MAPK inhibitors in the future.

Potential convergence of olfactory dysfunction in Parkinson's disease and COVID-19: The role of neuroinflammation

Parkinson's disease (PD) is a prevalent neurodegenerative disorder that affects 7-10 million individuals worldwide. A common early symptom of PD is olfactory dysfunction (OD), and more than 90% of PD patients suffer from OD. Recent studies have highlighted a high incidence of OD in patients with SARS-CoV-2 infection. This review investigates the potential convergence of OD in PD and COVID-19, particularly focusing on the mechanisms by which neuroinflammation contributes to OD and neurological events. Starting from our fundamental understanding of the olfactory bulb, we summarize the clinical features of OD and pathological features of the olfactory bulb from clinical cases and autopsy reports in PD patients. We then examine SARS-CoV-2-induced olfactory bulb neuropathology and OD and emphasize the SARS-CoV-2-induced neuroinflammatory cascades potentially leading to PD manifestations. By activating microglia and astrocytes, as well as facilitating the aggregation of α-synuclein, SARS-CoV-2 could contribute to the onset or exacerbation of PD. We also discuss the possible contributions of NF-κB, the NLRP3 inflammasome, and the JAK/STAT, p38 MAPK, TLR4, IL-6/JAK2/STAT3 and cGAS-STING signaling pathways. Although olfactory dysfunction in patients with COVID-19 may be reversible, it is challenging to restore OD in patients with PD. With the emergence of new SARS-CoV-2 variants and the recurrence of infections, we call for continued attention to the intersection between PD and SARS-CoV-2 infection, especially from the perspective of OD.

Curcumin/TGF-β1 siRNA loaded solid lipid nanoparticles alleviate cerebral injury after intracerebral hemorrhage by transnasal brain targeting

Intracerebral hemorrhage (ICH) is a prevalent cerebrovascular disorder. The inflammation induced by cerebral hemorrhage plays a crucial role in the secondary injury of ICH and often accompanied by a poor prognosis, leading to disease exacerbation. However, blood-brain barrier (BBB) limiting the penetration of therapeutic drugs to the brain. In this paper, our primary objective is to develop an innovative, non-invasive, safe, and targeted formulation. This novel approach aims to synergistically harness the combined therapeutic effects of drugs to intervene in inflammation via a non-injectable route, thereby significantly mitigating the secondary damage precipitated by inflammation following ICH. Thus, a novel "anti-inflammatory" cationic solid lipid nanoparticles (SLN) with targeting ability were constructed, which can enhance the stability of curcumin(CUR) and siRNA. We successfully developed SLN loaded with TGF-β1 siRNA and CUR (siRNA/CUR@SLN) that adhere to the requirements of drug delivery system by transnasal brain targeting. Through the characterization of nanoparticle properties, cytotoxicity assessment, in vitro pharmacological evaluation, and brain-targeting evaluation after nasal administration, siRNA/CUR@SLN exhibited a nearly spherical structure with a particle size of 125.0±1.93 nm, low cytotoxicity, high drug loading capacity, good sustained release function and good stability. In vitro anti-inflammatory results showcasing its remarkable anti-inflammatory activity. Moreover, in vivo pharmacological studies revealed that siRNA/CUR@SLN can be successfully delivered to brain tissue. Furthermore, it also elicited an effective anti-inflammatory response, alleviating brain inflammation. These results indicated that favorable brain-targeting ability and anti-inflammatory effects of siRNA/CUR@SLN in ICH model mice. In conclusion, our designed siRNA/CUR@SLN showed good brain targeting and anti-inflammatory effect ability after nasal administration, which lays the foundation for the treatment of inflammation caused by ICH and offers a novel approach for brain-targeted drug delivery and brings new hope.

Three Modes of Viral Adaption by the Heart

Viruses elicit long-term adaptive responses in the tissues they infect. Understanding viral adaptions in humans is difficult in organs such as the heart, where primary infected material is not routinely collected. In search of asymptomatic infections with accompanying host adaptions, we mined for cardio-pathogenic viruses in the unaligned reads of nearly one thousand human hearts profiled by RNA sequencing. Among virus-positive cases (~20%), we identified three robust adaptions in the host transcriptome related to inflammatory NFκB signaling and post-transcriptional regulation by the p38-MK2 pathway. The adaptions are not determined by the infecting virus, and they recur in infections of human or animal hearts and cultured cardiomyocytes. Adaptions switch states when NFκB or p38-MK2 are perturbed in cells engineered for chronic infection by the cardio-pathogenic virus, coxsackievirus B3. Stratifying viral responses into reversible adaptions adds a targetable systems-level simplification for infections of the heart and perhaps other organs.

Ginseng and ginsenosides on cardiovascular and pulmonary diseases; Pharmacological potentials for the coronavirus (COVID-19)

Since its outbreak in late 2019, the Coronavirus disease 2019 (COVID-19) pandemic has profoundly caused global morbidity and deaths. The COVID-19 pandemic caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has major complications in cardiovascular and pulmonary system. The increased rate of mortality is due to delayed detection of certain biomarkers that are crucial in the development of disease. Furthermore, certain proteins and enzymes in cellular signaling pathways play an important role in replication of SARS-CoV-2. Most cases are mild to moderate symptoms, however severe cases of COVID-19 leads to death. Detecting the level of biomarkers such as C-reactive protein, cardiac troponin, creatine kinase, creatine kinase-MB, procalcitonin and Matrix metalloproteinases helps in early detection of the severity of disease. Similarly, through downregulating Renin-angiotensin system, interleukin, Mitogen-activated protein kinases and Phosphoinositide 3-kinases pathways, COVID-19 can be effectively controlled and mortality could be prevented. Ginseng and ginsenosides possess therapeutic potential in cardiac and pulmonary complications, there are several studies performed in which they have suppressed these biomarkers and downregulated the pathways, thereby inhibiting the further spread of disease. Supplementation with ginseng or ginsenoside could act on multiple pathways to reduce the level of biomarkers significantly and alleviate cardiac and pulmonary damage. Therefore, this review summarizes the potential of ginseng extract and ginsenosides in controlling the cardiovascular and pulmonary diseases by COVID-19.

Evaluating NSAIDs in SARS-CoV-2: Immunomodulatory mechanisms and future therapeutic strategies

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely recognized for their analgesic and anti-inflammatory properties. Amidst the SARS-CoV-2 pandemic, the role of NSAIDs in modulating viral and bacterial infections has become a critical area of research, sparking debates and necessitating a thorough review. This review examines the multifaceted interactions between NSAIDs, immune responses, and infections. Focusing on the immunomodulatory mechanisms of NSAIDs in SARS-CoV-2 and their implications for other viral and bacterial infections, we aim to provide clarity and direction for future therapeutic strategies. NSAIDs demonstrate a dual role in infectious diseases. They reduce inflammation by decreasing neutrophil recruitment and cytokine release, yet potentially compromise antiviral defense mechanisms. They also modulate cytokine storms in SARS-CoV-2 and exhibit the potential to enhance anti-tumor immunity by inhibiting tumor-induced COX-2/PGE2 signaling. Specific NSAIDs have shown efficacy in inhibiting viral replication. The review highlights NSAIDs' synergy with other medications, like COX inhibitors and immunotherapy agents, in augmenting therapeutic effects. Notably, the World Health Organization's analysis found no substantial link between NSAIDs and the worsening of viral respiratory infections. The findings underscore NSAIDs' complex role in infection management. Understanding these interactions is crucial for optimizing therapeutic approaches in current and future pandemics. However, their dual nature warrants cautious application, particularly in vulnerable populations. NSAIDs present a paradoxical impact on immune responses in viral and bacterial infections. While offering potential benefits, their usage in infectious diseases, especially SARS-CoV-2, demands a nuanced understanding to balance therapeutic advantages against possible adverse effects.

SARS-CoV-2 spike protein-ACE2 interaction increases carbohydrate sulfotransferases and reduces N-acetylgalactosamine-4-sulfatase by p38 MAPK

Immunostaining in lungs of patients who died with COVID-19 infection showed increased intensity and distribution of chondroitin sulfate and decline in N-acetylgalactostamine-4-sulfatase (Arylsulfatase B; ARSB). To explain these findings, human small airway epithelial cells were exposed to the SARS-CoV-2 spike protein receptor binding domain (SPRBD) and transcriptional mechanisms were investigated. Phospho-p38 MAPK and phospho-SMAD3 increased following exposure to the SPRBD, and their inhibition suppressed the promoter activation of the carbohydrate sulfotransferases CHST15 and CHST11, which contributed to chondroitin sulfate biosynthesis. Decline in ARSB was mediated by phospho-38 MAPK-induced N-terminal Rb phosphorylation and an associated increase in Rb-E2F1 binding and decline in E2F1 binding to the ARSB promoter. The increases in chondroitin sulfotransferases were inhibited when treated with phospho-p38-MAPK inhibitors, SMAD3 (SIS3) inhibitors, as well as antihistamine desloratadine and antibiotic monensin. In the mouse model of carrageenan-induced systemic inflammation, increases in phospho-p38 MAPK and expression of CHST15 and CHST11 and declines in DNA-E2F binding and ARSB expression occurred in the lung, similar to the observed effects in this SPRBD model of COVID-19 infection. Since accumulation of chondroitin sulfates is associated with fibrotic lung conditions and diffuse alveolar damage, increased attention to p38-MAPK inhibition may be beneficial in ameliorating Covid-19 infections.

Elevated Arterial Blood Pressure as a Delayed Complication Following COVID-19-A Narrative Review

Arterial hypertension is one of the most common and significant cardiovascular risk factors. There are many well-known and identified risk factors for its development. In recent times, there has been growing concern about the potential impact of COVID-19 on the cardiovascular system and its relation to arterial hypertension. Various theories have been developed that suggest a connection between COVID-19 and elevated blood pressure. However, the precise link between SARS-CoV-2 infection and the long-term risk of developing hypertension remains insufficiently explored. Therefore, the primary objective of our study was to investigate the influence of COVID-19 infection on blood pressure elevation and the subsequent risk of developing arterial hypertension over an extended period. To accomplish this, we conducted a thorough search review of relevant papers in the PubMed and SCOPUS databases up to 3 September 2023. Our analysis encompassed a total of 30 eligible articles. Out of the 30 papers we reviewed, 19 of them provided substantial evidence showing a heightened risk of developing arterial hypertension following COVID-19 infection. Eight of the studies showed that blood pressure values increased after the infection, while three of the qualified studies did not report any notable impact of COVID-19 on blood pressure levels. The precise mechanism behind the development of hypertension after COVID-19 remains unclear, but it is suggested that endothelial injury and dysfunction of the renin-angiotensin-aldosterone system may be contributory. Additionally, changes in blood pressure following COVID-19 infection could be linked to lifestyle alterations that often occur alongside the illness. Our findings emphasize the pressing requirement for thorough research into the relationship between COVID-19 and hypertension. These insights are essential for the development of effective prevention and management approaches for individuals who have experienced COVID-19 infection.

Duck Tembusu virus infection activates the MKK3/6-p38 MAPK signaling pathway to promote virus replication

Duck Tembusu virus (DTMUV) infection poses a serious threat to ducks, chickens, and geese, causing a range of detrimental effects, including reduced egg production, growth retardation, and even death. These consequences lead to substantial economic losses for the Chinese poultry industry. Although it is established that various viral infections can trigger activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway, the precise role and mechanisms underlying p38 MAPK activation in DTMUV infection remain poorly understood. To address this knowledge gap, we conducted a study to investigate whether the replication of DTMUV necessitates the activation of p38 MAPK. We found that DTMUV infection stimulates activation of the MKK3/6-p38 MAPK pathway, and the activation of p38 MAPK increases with viral titer. Subsequently, the use of the small molecule inhibitor SB203580 significantly reduced DTMUV replication by inhibiting p38 MAPK activity. Furthermore, downregulation of p38 MAPK protein expression by siRNA also inhibited DTMUV replication, whereas transient transfection of p38 MAPK protein promoted DTMUV replication. Interestingly, we found that the DTMUV capsid protein activates p38 MAPK, and there is interaction between DTMUV capsid and p38 MAPK. Finally, we found that DTMUV infection induces elevated mRNA expression of IFN-α, IFN-β, IFN-γ, IL-1β, IL-6, and IL-12, which is associated with p38 MAPK activity. These results indicated that virus hijacking of p38 activation is a crucial event for DTMUV replication, and that pharmacological blockade of p38 activation represents a potential anti-DTMUV strategy.

Suppressed transcript diversity and immune response in COVID-19 ICU patients: a longitudinal study

Understanding the dynamic changes in gene expression during Acute Respiratory Distress Syndrome (ARDS) progression in post-acute infection patients is crucial for unraveling the underlying mechanisms. Study investigates the longitudinal changes in gene/transcript expression patterns in hospital-admitted severe COVID-19 patients with ARDS post-acute SARS-CoV-2 infection. Blood samples were collected at three time points and patients were stratified into severe and mild ARDS, based on their oxygenation saturation (SpO2/FiO2) kinetics over 7 d. Decline in transcript diversity was observed over time, particularly in patients with higher severity, indicating dysregulated transcriptional landscape. Comparing gene/transcript-level analyses highlighted a rather limited overlap. With disease progression, a transition towards an inflammatory state was evident. Strong association was found between antibody response and disease severity, characterized by decreased antibody response and activated B cell population in severe cases. Bayesian network analysis identified various factors associated with disease progression and severity, viz. humoral response, TLR signaling, inflammatory response, interferon response, and effector T cell abundance. The findings highlight dynamic gene/transcript expression changes during ARDS progression, impact on tissue oxygenation and elucidate disease pathogenesis.

Immune and metabolic perturbations in COVID-19-associated pulmonary mucormycosis: A transcriptome analysis of innate immune cells

BACKGROUND AND OBJECTIVES

The mechanisms underlying COVID-19-associated pulmonary mucormycosis (CAPM) remain unclear. We use a transcriptomic analysis of the innate immune cells to investigate the host immune and metabolic response pathways in patients with CAPM.

PATIENTS AND METHODS

We enrolled subjects with CAPM (n = 5), pulmonary mucormycosis (PM) without COVID-19 (n = 5), COVID-19 (without mucormycosis, n = 5), healthy controls (n = 5) without comorbid illness and negative for SARS-CoV-2. Peripheral blood samples from cases were collected before initiating antifungal therapy, and neutrophils and monocytes were isolated. RNA sequencing was performed using Illumina HiSeqX from monocytes and neutrophils. Raw reads were aligned with HISAT-2 pipeline and DESeq2 was used for differential gene expression. Gene ontology (GO) and metabolic pathway analysis were performed using Shiny GO application and R packages (ggplot2, Pathview).

RESULTS

The derangement of core immune and metabolic responses in CAPM patients was noted. Pattern recognition receptors, dectin-2, MCL, FcRγ receptors and CLEC-2, were upregulated, but signalling pathways such as JAK-STAT, IL-17 and CARD-9 were downregulated; mTOR and MAP-kinase signalling were elevated in monocytes from CAPM patients. The complement receptors, NETosis, and pro-inflammatory responses, such as S100A8/A9, lipocalin and MMP9, were elevated. The major metabolic pathways of glucose metabolism-glycolysis/gluconeogenesis, pentose phosphate pathway, HIF signalling and iron metabolism-ferroptosis were also upregulated in CAPM.

CONCLUSIONS

We identified significant alterations in the metabolic pathways possibly leading to cellular iron overload and a hyperglycaemic state. Immune responses revealed altered recognition, signalling, effector functions and a pro-inflammatory state in monocytes and neutrophils from CAPM patients.

Perspectives on Post-COVID-19 Pulmonary Fibrosis Treatment

Pulmonary fibrosis, a critical outcome of chronic inflammatory diseases, has gained prominence in the context of post-coronavirus (post-COVID-19) complications. This review delves into the multifaceted landscape of post-COVID-19 pulmonary fibrosis, elucidating the intricate molecular mechanisms underlying its pathogenesis and highlighting promising therapeutic avenues. Examining the aftermath of severe acute respiratory syndrome-2 (SARS-CoV-2) infection, the review reveals key signaling pathways implicated in the fibrotic cascade. Drawing parallels with previous coronavirus outbreaks enhances our understanding of the distinctive features of post-COVID-19 fibrosis. Antifibrotic drugs, like pirfenidone and nintedanib, take center stage; their mechanisms of action and potential applications in post-COVID-19 cases are thoroughly explored. Beyond the established treatments, this review investigates emerging therapeutic modalities, including anti-interleukin agents, immunosuppressants, and experimental compounds, like buloxybutide, saracatinib, sirolimus, and resveratrol. Emphasizing the critical importance of early intervention, this review highlights the dynamic nature of post-COVID-19 pulmonary fibrosis research. In conclusion, the synthesis of current knowledge offers a foundation for advancing our approaches to the prevention and treatment of these consequential sequelae of COVID-19.

Circulating miRNA profiles in COVID-19 patients and meta-analysis: implications for disease progression and prognosis

We compared circulating miRNA profiles of hospitalized COVID-positive patients (n = 104), 27 with acute respiratory distress syndrome (ARDS) and age- and sex-matched healthy controls (n = 18) to identify miRNA signatures associated with COVID and COVID-induced ARDS. Meta-analysis incorporating data from published studies and our data was performed to identify a set of differentially expressed miRNAs in (1) COVID-positive patients versus healthy controls as well as (2) severe (ARDS+) COVID vs moderate COVID. Gene ontology enrichment analysis of the genes these miRNAs interact with identified terms associated with immune response, such as interferon and interleukin signaling, as well as viral genome activities associated with COVID disease and severity. Additionally, we observed downregulation of a cluster of miRNAs located on chromosome 14 (14q32) among all COVID patients. To predict COVID disease and severity, we developed machine learning models that achieved AUC scores between 0.81-0.93 for predicting disease, and between 0.71-0.81 for predicting severity, even across diverse studies with different sample types (plasma versus serum), collection methods, and library preparations. Our findings provide network and top miRNA feature insights into COVID disease progression and contribute to the development of tools for disease prognosis and management.

Drug repurposing for the treatment of COVID-19: Targeting nafamostat to the lungs by a liposomal delivery system

Despite tremendous global efforts since the beginning of the COVID-19 pandemic, still only a limited number of prophylactic and therapeutic options are available. Although vaccination is the most effective measure in preventing morbidity and mortality, there is a need for safe and effective post-infection treatment medication. In this study, we explored a pipeline of 21 potential candidates, examined in the Calu-3 cell line for their antiviral efficacy, for drug repurposing. Ralimetinib and nafamostat, clinically used drugs, have emerged as attractive candidates. Due to the inherent limitations of the selected drugs, we formulated targeted liposomes suitable for both systemic and intranasal administration. Non-targeted and targeted nafamostat liposomes (LipNaf) decorated with an Apolipoprotein B peptide (ApoB-P) as a specific lung-targeting ligand were successfully developed. The developed liposomal formulations of nafamostat were found to possess favorable physicochemical properties including nano size (119-147 nm), long-term stability of the normally rapidly degrading compound in aqueous solution, negligible leakage from the liposomes upon storage, and a neutral surface charge with low polydispersity index (PDI). Both nafamostat and ralimetinib liposomes showed good cellular uptake and lack of cytotoxicity, and non-targeted LipNaf demonstrated enhanced accumulation in the lungs following intranasal (IN) administration in non-infected mice. LipNaf retained its anti-SARS-CoV 2 activity in Calu 3 cells with only a modest decrease, exhibiting complete inhibition at concentrations >100 nM. IN, but not intraperitoneal (IP) treatment with targeted LipNaf resulted in a trend to reduced viral load in the lungs of K18-hACE2 mice compared to targeted empty Lip. Nevertheless, upon removal of outlier data, a statistically significant 1.9-fold reduction in viral load was achieved. This observation further highlights the importance of a targeted delivery into the respiratory tract. In summary, we were able to demonstrate a proof-of-concept of drug repurposing by liposomal formulations with anti-SARS-CoV-2 activity. The biodistribution and bioactivity studies with LipNaf suggest an IN or inhalation route of administration for optimal therapeutic efficacy.

New insights on the potential effect of progesterone in Covid-19: Anti-inflammatory and immunosuppressive effects

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a pandemic disease caused by severe acute respiratory syndrome CoV type 2 (SARS-CoV-2). COVID-19 is higher in men than women and sex hormones have immune-modulator effects during different viral infections, including SARS-CoV-2 infection. One of the essential sex hormones is progesterone (P4).

AIMS

This review aimed to reveal the association between P4 and Covid-19.

RESULTS AND DISCUSSION

The possible role of P4 in COVID-19 could be beneficial through the modulation of inflammatory signaling pathways, induction of the release of anti-inflammatory cytokines, and inhibition release of pro-inflammatory cytokines. P4 stimulates skew of naïve T cells from inflammatory Th1 toward anti-inflammatory Th2 with activation release of anti-inflammatory cytokines, and activation of regulatory T cells (Treg) with decreased interferon-gamma production that increased during SARS-CoV-2 infection. In addition, P4 is regarded as a potent antagonist of mineralocorticoid receptor (MR), it could reduce MRs that were activated by stimulated aldosterone from high AngII during SARS-CoV-2. P4 active metabolite allopregnanolone is regarded as a neurosteroid that acts as a positive modulator of γ-aminobutyric acid (GABAA ) so it may reduce neuropsychiatric manifestations and dysautonomia in COVID-19 patients.

CONCLUSION

Taken together, the anti-inflammatory and immunomodulatory properties of P4 may improve central and peripheral complications in COVID-19.

Modulation of various host cellular machinery during COVID-19 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) emerged in December 2019, causing a range of respiratory infections from mild to severe. This resulted in the ongoing global COVID-19 pandemic, which has had a significant impact on public health. The World Health Organization declared COVID-19 as a global pandemic in March 2020. Viruses are intracellular pathogens that rely on the host's machinery to establish a successful infection. They exploit the gene expression machinery of host cells to facilitate their own replication. Gaining a better understanding of gene expression modulation in SARS-CoV2 is crucial for designing and developing effective antiviral strategies. Efforts are currently underway to understand the molecular-level interaction between the host and the pathogen. In this review, we describe how SARS-CoV2 infection modulates gene expression by interfering with cellular processes, including transcription, post-transcription, translation, post-translation, epigenetic modifications as well as processing and degradation pathways. Additionally, we emphasise the therapeutic implications of these findings in the development of new therapies to treat SARS-CoV2 infection.

Dysregulation of intracellular redox homeostasis by the SARS-CoV-2 ORF6 protein

SARS-CoV-2 has evolved several strategies to overcome host cell defenses by inducing cell injury to favour its replication. Many viruses have been reported to modulate the intracellular redox balance, affecting the Nuclear factor erythroid 2-Related Factor 2 (NRF2) signaling pathway. Although antioxidant modulation by SARS-CoV-2 infection has already been described, the viral factors involved in modulating the NRF2 pathway are still elusive. Given the antagonistic activity of ORF6 on several cellular pathways, we investigated the role of the viral protein towards NRF2-mediated antioxidant response. The ectopic expression of the wt-ORF6 protein negatively impacts redox cell homeostasis, leading to an increase in ROS production, along with a decrease in NRF2 protein and its downstream controlled genes. Moreover, when investigating the Δ61 mutant, previously described as an inactive nucleopore proteins binding mutant, we prove that the oxidative stress induced by ORF6 is substantially related to its C-terminal domain, speculating that ORF6 mechanism of action is associated with the inhibition of nuclear mRNA export processes. In addition, activation by phosphorylation of the serine residue at position 40 of NRF2 is increased in the cytoplasm of wt-ORF6-expressing cells, supporting the presence of an altered redox state, although NRF2 nuclear translocation is hindered by the viral protein to fully antagonize the cell response. Furthermore, wt-ORF6 leads to phosphorylation of a stress-activated serine/threonine protein kinase, p38 MAPK, suggesting a role of the viral protein in regulating p38 activation. These findings strengthen the important role of oxidative stress in the pathogenesis of SARS-CoV-2 and identify ORF6 as an important viral accessory protein hypothetically involved in modulating the antioxidant response during viral infection.

Protective effect of β-glucan on Poly(I:C)-induced acute lung injury/inflammation: Therapeutic implications of viral infections in the respiratory system

AIMS

Acute lung inflammation, particularly acute respiratory distress syndrome (ARDS), is caused by a variety of pathogens including bacteria and viruses. β-Glucans have been reported to possess both anti-inflammatory and immunomodulatory properties. The current study evaluated the therapeutic effect of β-glucans on polyinosinic:polycytidylic acid (Poly(I:C)) induced lung inflammation in both hamster and mice models.

MAIN METHODS

Poly(I:C)-induced ALI/inflammation models were developed in hamsters (2.5 mg/kg) and mice (2 mg/kg) by delivering the Poly(I:C) intratracheally, and followed with and without β-glucan administration. After treatment, lung mechanics were assessed and lung tissues were isolated and analyzed for mRNA/protein expression, and histopathological examinations.

KEY FINDINGS

Poly(I:C) administration, caused a significant elevation of inflammatory marker's expression in lung tissues and showed abnormal lung mechanics in mice and hamsters. Interestingly, treatment with β-glucan significantly (p < 0.001) reversed the Poly(I:C)-induced inflammatory events and inflammatory markers expression in both mRNA (IL-6, IL-1β, TNF-α, CCL2 and CCL7) and protein levels (TNF-α, CD68, myeloperoxidase, neutrophil elastase, MUC-5Ac and iNOS). Lung functional assays revealed that β-glucan treatment significantly improved lung mechanics. Histopathological analysis showed that β-glucan treatment significantly attenuated the Poly(I:C) induced inflammatory cell infiltration, injury and goblet cell population in lung tissues. Consistent with these findings, β-glucan treatment markedly reduced the number of neutrophils and macrophages in lung tissues. Our findings further demonstrated that β-glucan could reduce inflammation by suppressing the MAPK pathway.

SIGNIFICANCE

These results suggested that β-glucan may attenuate the pathogenic effects of Poly(I:C)-induced ALI/ARDS via modulating the MAPK pathway, indicating β-glucan as a possible therapeutic agent for the treatment of viral-pulmonary inflammation/injury.

The effects of prolactin on the immune system, its relationship with the severity of COVID-19, and its potential immunomodulatory therapeutic effect

Prolactin (PRL) is an endocrine hormone secreted by the anterior pituitary gland that has a variety of physiological effects, including milk production, immune system regulation, and anti-inflammatory effects. Elevated levels of PRL have been found in several viral infections, including 2019 coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), a viral pathogen that has recently spread worldwide. PRL production is increased in SARS-CoV2 infection. While PRL can trigger the production of proinflammatory cytokines, it also has several anti-inflammatory effects that can reduce hyperinflammation. The exact mechanism of PRL's contribution to the severity of COVID-19 is unknown. The purpose of this review is to discuss the interaction between PRL and SARS-CoV2 infection and its possible association with the severity of COVID-19.

Severe acute respiratory syndrome coronavirus 2 infection leads to Tau pathological signature in neurons

COVID-19 has represented an issue for global health since its outbreak in March 2020. It is now evident that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in a wide range of long-term neurological symptoms and is worryingly associated with the aggravation of Alzheimer's disease. Little is known about the molecular basis of these manifestations. Here, several strain variants were used to infect SH-SY5Y neuroblastoma cells and K18-hACE C57BL/6J mice. The Tau phosphorylation profile and aggregation propensity upon infection were investigated on cellular extracts, subcellular fractions, and brain tissue. The viral proteins spike, nucleocapsid, and membrane were overexpressed in SH-SY5Y cells, and the direct interaction and effect on Tau phosphorylation were checked using immunoblot experiments. Upon infection, Tau is phosphorylated at several pathological epitopes associated with Alzheimer's disease and other tauopathies. Moreover, this event increases Tau's propensity to form insoluble aggregates and alters its subcellular localization. Our data support the hypothesis that SARS-CoV-2 infection in the central nervous system triggers downstream effects altering Tau function, eventually leading to the impairment of neuronal function.

Therapeutic prospects of naturally occurring p38 MAPK inhibitors tanshinone IIA and pinocembrin for the treatment of SARS-CoV-2-induced CNS complications

P38 mitogen-activated protein kinase (p38 MAPK) signaling pathway is closely related to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) replication and hyperinflammatory responses in coronavirus disease 2019 (COVID-19). Therefore, blood-brain barrier-penetrating p38 MAPK inhibitors have good potential for the treatment of central nervous system (CNS) complications of COVID-19. The aim of the present study is the characterization of the therapeutic potential of tanshinone IIA and pinocembrin for the treatment of CNS complications of COVID-19. Studies published in high-quality journals indexed in databases Scopus, Web of Science, PubMed, and so forth were used to review the therapeutic capabilities of selected compounds. In continuation of our previous efforts to identify agents with favorable activity/toxicity profiles for the treatment of COVID-19, tanshinone IIA and pinocembrin were identified with a high ability to penetrate the CNS. Considering the nature of the study, no specific time frame was determined for the selection of studies, but the focus was strongly on studies published after the emergence of COVID-19. By describing the association of COVID-19-induced CNS disorders with p38 MAPK pathway disruption, this study concludes that tanshinone IIA and pinocembrin have great potential for better treatment of these complications. The inclusion of these compounds in the drug regimen of COVID-19 patients requires confirmation of their effectiveness through the conduction of high-quality clinical trials.

Identification of shared biological features in four different lung cell lines infected with SARS-CoV-2 virus through RNA-seq analysis

The COVID-19 pandemic caused by SARS-CoV-2 has resulted in millions of confirmed cases and deaths worldwide. Understanding the biological mechanisms of SARS-CoV-2 infection is crucial for the development of effective therapies. This study conducts differential expression (DE) analysis, pathway analysis, and differential network (DN) analysis on RNA-seq data of four lung cell lines, NHBE, A549, A549.ACE2, and Calu3, to identify their common and unique biological features in response to SARS-CoV-2 infection. DE analysis shows that cell line A549.ACE2 has the highest number of DE genes, while cell line NHBE has the lowest. Among the DE genes identified for the four cell lines, 12 genes are overlapped, associated with various health conditions. The most significant signaling pathways varied among the four cell lines. Only one pathway, "cytokine-cytokine receptor interaction", is found to be significant among all four cell lines and is related to inflammation and immune response. The DN analysis reveals considerable variation in the differential connectivity of the most significant pathway shared among the four lung cell lines. These findings help to elucidate the mechanisms of SARS-CoV-2 infection and potential therapeutic targets.

SARS-CoV-2 infection perturbs enhancer mediated transcriptional regulation of key pathways

Despite extensive studies on the effects of SARS-CoV-2 infection, there is still a lack of understanding of the downstream epigenetic and regulatory alterations in infected cells. In this study, we investigated changes in enhancer acetylation in epithelial lung cells infected with SARS-CoV-2 and their influence on transcriptional regulation and pathway activity. To achieve this, we integrated and reanalyzed data of enhancer acetylation, ex-vivo infection and single cell RNA-seq data from human patients. Our findings revealed coordinated changes in enhancers and transcriptional networks. We found that infected cells lose the WT1 transcription factor and demonstrate disruption of WT1-bound enhancers and of their associated target genes. Downstream targets of WT1 are involved in the regulation of the Wnt signaling and the mitogen-activated protein kinase cascade, which indeed exhibit increased activation levels. These findings may provide a potential explanation for the development of pulmonary fibrosis, a lethal complication of COVID-19. Moreover, we revealed over-acetylated enhancers associated with upregulated genes involved in cell adhesion, which could contribute to cell-cell infection of SARS-CoV-2. Furthermore, we demonstrated that enhancers may play a role in the activation of pro-inflammatory cytokines and contribute to excessive inflammation in the lungs, a typical complication of COVID-19. Overall, our analysis provided novel insights into the cell-autonomous dysregulation of enhancer regulation caused by SARS-CoV-2 infection, a step on the path to a deeper molecular understanding of the disease.

Role of the Renin-Angiotensin System in Long COVID's Cardiovascular Injuries

The renin-angiotensin system (RAS) is one of the biggest challenges of cardiovascular medicine. The significance of the RAS in the chronic progression of SARS-CoV-2 infection and its consequences is one of the topics that are currently being mostly discussed. SARS-CoV-2 undermines the balance between beneficial and harmful RAS pathways. The level of soluble ACE2 and membrane-bound ACE2 are both upregulated by the endocytosis of the SARS-CoV-2/ACE2 complex and the tumor necrosis factor (TNF)-α-converting enzyme (ADAM17)-induced cleavage. Through the link between RAS and the processes of proliferation, the processes of fibrous remodelling of the myocardium are initiated from the acute phase of the disease, continuing into the long COVID stage. In the long term, RAS dysfunction may cause an impairment of its beneficial effects leading to thromboembolic processes and a reduction in perfusion of target organs. The main aspects of ACE2-a key pathogenic role in COVID-19 as well as the mechanisms of RAS involvement in COVID cardiovascular injuries are studied. Therapeutic directions that can be currently anticipated in relation to the various pathogenic pathways of progression of cardiovascular damage in patients with longCOVID have also been outlined.

Targeting SARS-CoV-2 Main Protease (MPro) with Kinase Inhibitors: A Promising Approach for Discovering Antiviral and Anti-inflammatory Molecules against SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus infected over 688 million people worldwide, causing public health concern and approximately 6.8 million deaths due to COVID-19. COVID-19, especially severe cases, is characterized by exacerbated lung inflammation with an increase of pro-inflammatory cytokines. In addition to antiviral drugs, there is a need for anti-inflammatory therapies to treat all phases of COVID-19. One of the most attractive drug targets for COVID-19 is the SARS-CoV-2 main protease (MPro), an enzyme responsible for cleaving polyproteins formed after the translation of viral RNA, which is essential for viral replication. MPro inhibitors, therefore, have the potential to stop viral replication and act as antiviral drugs. Considering that several kinase inhibitors are known for their action in inflammatory pathways, this could also be investigated toward a potential anti-inflammatory treatment for COVID-19. Therefore, the use of kinase inhibitors against SARS-CoV-2 MPro may be a promising strategy to find molecules with dual activity─antiviral and anti-inflammatory. Considering this, the potential of six kinase inhibitors against SARS-CoV-2 MPro were evaluated in silico and in vitro, including Baricitinib, Tofacitinib, Ruxolitinib, BIRB-796, Skepinone-L, and Sorafenib. To assess the inhibitory potential of the kinase inhibitors, a continuous fluorescent-based enzyme activity assay was optimized with SARS-CoV-2 MPro and MCA-AVLQSGFR-K(Dnp)-K-NH2 (substrate). BIRB-796 and Baricitinib were identified as inhibitors of SARS-CoV-2 MPro, presenting IC₅₀ values of 7.99 and 25.31 μM, respectively. As they are also known for their anti-inflammatory action, both are prototype compounds with the potential to present antiviral and anti-inflammatory activity against SARS-CoV-2 infection.

Study of kaempferol in the treatment of COVID-19 combined with Chikungunya co-infection by network pharmacology and molecular docking technology

Chikungunya (CHIK) patients may be vulnerable to coronavirus disease (COVID-19). However, presently there are no anti-COVID-19/CHIK therapeutic alternatives available. The purpose of this research was to determine the pharmacological mechanism through which kaempferol functions in the treatment of COVID-19-associated CHIK co-infection. We have used a series of network pharmacology and computational analysis-based techniques to decipher and define the binding capacity, biological functions, pharmacological targets, and treatment processes in COVID-19-mediated CHIK co-infection. We identified key therapeutic targets for COVID-19/CHIK, including TP53, MAPK1, MAPK3, MAPK8, TNF, IL6 and NFKB1. Gene ontology, molecular and upstream pathway analysis of kaempferol against COVID-19 and CHIK showed that DEGs were confined mainly to the cytokine-mediated signalling pathway, MAP kinase activity, negative regulation of the apoptotic process, lipid and atherosclerosis, TNF signalling pathway, hepatitis B, toll-like receptor signaling, IL-17 and IL-18 signaling pathways. The study of the gene regulatory network revealed several significant TFs including KLF16, GATA2, YY1 and FOXC1 and miRNAs such as let-7b-5p, mir-16-5p, mir-34a-5p, and mir-155-5p that target differential-expressed genes (DEG). According to the molecular coupling results, kaempferol exhibited a high affinity for 5 receptor proteins (TP53, MAPK1, MAPK3, MAPK8, and TNF) compared to control inhibitors. In combination, our results identified significant targets and pharmacological mechanisms of kaempferol in the treatment of COVID-19/CHIK and recommended that core targets be used as potential biomarkers against COVID-19/CHIK viruses. Before conducting clinical studies for the intervention of COVID-19 and CHIK, kaempferol might be evaluated in wet lab tests at the molecular level.

Repurposing clinically available drugs and therapies for pathogenic targets to combat SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic has affected a large portion of the global population, both physically and mentally. Current evidence suggests that the rapidly evolving coronavirus subvariants risk rendering vaccines and antibodies ineffective due to their potential to evade existing immunity, with enhanced transmission activity and higher reinfection rates that could lead to new outbreaks across the globe. The goal of viral management is to disrupt the viral life cycle as well as to relieve severe symptoms such as lung damage, cytokine storm, and organ failure. In the fight against viruses, the combination of viral genome sequencing, elucidation of the structure of viral proteins, and identifying proteins that are highly conserved across multiple coronaviruses has revealed many potential molecular targets. In addition, the time- and cost-effective repurposing of preexisting antiviral drugs or approved/clinical drugs for these targets offers considerable clinical advantages for COVID-19 patients. This review provides a comprehensive overview of various identified pathogenic targets and pathways as well as corresponding repurposed approved/clinical drugs and their potential against COVID-19. These findings provide new insight into the discovery of novel therapeutic strategies that could be applied to the control of disease symptoms emanating from evolving SARS-CoV-2 variants.

Synthesis, In Silico Studies, and In Vitro Anti-Inflammatory Activity of Novel Imidazole Derivatives Targeting p38 MAP Kinase

A series of eight novel N-substituted [4-(trifluoro methyl)-1H-imidazole-1-yl] amide derivatives (AA1-AA8) were synthesized, characterized, and evaluated for their in vitro p38 MAP kinase anti-inflammatory inhibitory activity. The synthesized compounds were obtained by coupling [4-(trifluoromethyl)-1H-imidazole-1-yl] acetic acid with 2-amino-N-(Substituted)-3-phenylpropanamide derivatives utilizing 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b] pyridinium 3-oxide hexafluorophosphate as a coupling agent. Various spectroscopic methods established and confirmed their structures, specifically, ¹H NMR, ¹³C NMR, Fourier transform infrared (FTIR), and mass spectrometry. In order to emphasize the binding site of the p38 MAP kinase protein and newly synthesized compounds, molecular docking studies were carried out. In the series, compound AA6 had the highest docking score of 7.83 kcal/mol. The ADME studies were performed using web software. Studies revealed that all the synthesized compounds were orally active and showed good gastrointestinal absorption within the acceptable range. Lipinski's "rule of five" was used to determine drug-likeness. The synthesized compounds were screened for their anti-inflammatory activity by performing an albumin denaturation assay in which five compounds (AA2, AA3, AA4, AA5, and AA6) were found to exhibit substantial activity. Hence, these were further selected and proceeded for the evaluation of p38 MAP kinase inhibitory activity. The compound AA6 possesses considerable p38 kinase inhibitory anti-inflammatory activity with an IC₅₀ value of 403.57 ± 6.35 nM compared to the prototype drug adezmapimod (SB203580) with an IC₅₀ value of 222.44 ± 5.98 nM. Some further structural modifications in compound AA6 could contribute to the development of new p38 MAP kinase inhibitors with an improved IC₅₀ value.

Discovery of Chalcone-Based Hybrid Structures as High Affinity and Site-Specific Inhibitors against SARS-CoV-2: A Comprehensive Structural Analysis Based on Various Host-Based and Viral Targets

Previous studies indicated that natural-based chalcones have significant inhibitory effects on the coronavirus enzymes 3CLpro and PLpro as well as modulation of some host-based antiviral targets (HBATs). In this study, a comprehensive computational and structural study was performed to investigate the affinity of our compound library consisting of 757 chalcone-based structures (CHA-1 to CHA-757) for inhibiting the 3CLpro and PLpro enzymes and against twelve selected host-based targets. Our results indicated that CHA-12 (VUF 4819) is the most potent and multi-target inhibitor in our chemical library over all viral and host-based targets. Correspondingly, CHA-384 and its congeners containing ureide moieties were found to be potent and selective 3CLpro inhibitors, and benzotriazole moiety in CHA-37 was found to be a main fragment for inhibiting the 3CLpro and PLpro. Surprisingly, our results indicate that the ureide and sulfonamide moieties are integral fragments for the optimum 3CLpro inhibition while occupying the S1 and S3 subsites, which is fully consistent with recent reports on the site-specific 3CLpro inhibitors. Finding the multi-target inhibitor CHA-12, previously reported as an LTD4 antagonist for the treatment of inflammatory pulmonary diseases, prompted us to suggest it as a concomitant agent for relieving respiratory symptoms and suppressing COVID-19 infection.

Synthesis and Preclinical Positron Emission Tomography Imaging of the p38 MAPK Inhibitor [11C]Talmapimod: Effects of Drug Efflux and Sex Differences

Stress-activated kinases are targets of interest in neurodegenerative disease due to their involvement in inflammatory signaling and synaptic dysfunction. The p38α kinase has shown clinical and preclinical promise as a druggable target in several neurodegenerative conditions. We report the radiosynthesis and evaluation of the first positron emission tomography (PET) radiotracer for imaging MAPK p38α/β through radiolabeling of the inhibitor talmapimod (SCIO-469) with carbon-11. [¹¹C]Talmapimod was reliably synthesized by carbon-11 methylation with non-decay corrected radiochemical yields of 3.1 ± 0.7%, molar activities of 38.9 ± 13 GBq/μmol, and >95% radiochemical purity (n = 20). Preclinical PET imaging in rodents revealed a low baseline brain uptake and retention with standardized uptake values (SUV) of ∼0.2 over 90 min; however, pretreatment with the P-glycoprotein (P-gp) drug efflux transporter inhibitor elacridar enabled [¹¹C]talmapimod to pass the blood-brain barrier (>1.0 SUV) with distinct sex differences in washout kinetics. Blocking studies with a structurally dissimilar p38α/β inhibitor, neflamapimod (VX-745), and displacement imaging studies with talmapimod were attempted in elacridar-pretreated rodents, but neither compound displaced radiotracer uptake in the brain of either sex. Ex vivo radiometabolite analysis revealed substantial differences in the composition of radioactive species present in blood plasma but not in brain homogenates at 40 min post radiotracer injection. Digital autoradiography in fresh-frozen rodent brain tissue confirmed that the radiotracer signal was largely non-displaceable in vitro, where self-blocking and blocking with neflamapimod marginally decreased the total signal by 12.9 ± 8.8% and 2.66 ± 2.1% in C57bl/6 healthy controls and 29.3 ± 2.7% and 26.7 ± 12% in Tg2576 rodent brains, respectively. An MDCK-MDR1 assay suggests that talmapimod is likely to suffer from drug efflux in humans as well as rodents. Future efforts should focus on radiolabeling p38 inhibitors from other structural classes to avoid P-gp efflux and non-displaceable binding.

In silico identification of potential miRNAs -mRNA inflammatory networks implicated in the pathogenesis of COVID-19

COVID-19 has been found to affect the expression profile of several mRNAs and miRNAs, leading to dysregulation of a number of signaling pathways, particularly those related to inflammatory responses. In the current study, a systematic biology procedure was used for the analysis of high-throughput expression data from blood specimens of COVID-19 and healthy individuals. Differentially expressed miRNAs in blood specimens of COVID-19 vs. healthy specimens were then identified to construct and analyze miRNA-mRNA networks and predict key miRNAs and genes in inflammatory pathways. Our results showed that 171 miRNAs were expressed as outliers in box plot and located in the critical areas according to our statistical analysis. Among them, 8 miRNAs, namely miR-1275, miR-4429, miR-4489, miR-6721-5p, miR-5010-5p, miR-7110-5p, miR-6804-5p and miR-6881-3p were found to affect expression of key genes in NF-KB, JAK/STAT and MAPK signaling pathways implicated in COVID-19 pathogenesis. In addition, our results predicted that 25 genes involved in above-mentioned inflammatory pathways were targeted not only by these 8 miRNAs but also by other obtained miRNAs (163 miRNAs). The results of the current in silico study represent candidate targets for further studies in COVID-19.

A review of cytokine-based pathophysiology of Long COVID symptoms

The Long COVID/Post Acute Sequelae of COVID-19 (PASC) group includes patients with initial mild-to-moderate symptoms during the acute phase of the illness, in whom recovery is prolonged, or new symptoms are developed over months. Here, we propose a description of the pathophysiology of the Long COVID presentation based on inflammatory cytokine cascades and the p38 MAP kinase signaling pathways that regulate cytokine production. In this model, the SARS-CoV-2 viral infection is hypothesized to trigger a dysregulated peripheral immune system activation with subsequent cytokine release. Chronic low-grade inflammation leads to dysregulated brain microglia with an exaggerated release of central cytokines, producing neuroinflammation. Immunothrombosis linked to chronic inflammation with microclot formation leads to decreased tissue perfusion and ischemia. Intermittent fatigue, Post Exertional Malaise (PEM), CNS symptoms with "brain fog," arthralgias, paresthesias, dysautonomia, and GI and ophthalmic problems can consequently arise as result of the elevated peripheral and central cytokines. There are abundant similarities between symptoms in Long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). DNA polymorphisms and viral-induced epigenetic changes to cytokine gene expression may lead to chronic inflammation in Long COVID patients, predisposing some to develop autoimmunity, which may be the gateway to ME/CFS.

Pathogenic mechanisms of post-acute sequelae of SARS-CoV-2 infection (PASC)

COVID-19, with persistent and new onset of symptoms such as fatigue, post-exertional malaise, and cognitive dysfunction that last for months and impact everyday functioning, is referred to as Long COVID under the general category of post-acute sequelae of SARS-CoV-2 infection (PASC). PASC is highly heterogenous and may be associated with multisystem tissue damage/dysfunction including acute encephalitis, cardiopulmonary syndromes, fibrosis, hepatobiliary damages, gastrointestinal dysregulation, myocardial infarction, neuromuscular syndromes, neuropsychiatric disorders, pulmonary damage, renal failure, stroke, and vascular endothelial dysregulation. A better understanding of the pathophysiologic mechanisms underlying PASC is essential to guide prevention and treatment. This review addresses potential mechanisms and hypotheses that connect SARS-CoV-2 infection to long-term health consequences. Comparisons between PASC and other virus-initiated chronic syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome and postural orthostatic tachycardia syndrome will be addressed. Aligning symptoms with other chronic syndromes and identifying potentially regulated common underlining pathways may be necessary for understanding the true nature of PASC. The discussed contributors to PASC symptoms include sequelae from acute SARS-CoV-2 injury to one or more organs, persistent reservoirs of the replicating virus or its remnants in several tissues, re-activation of latent pathogens such as Epstein-Barr and herpes viruses in COVID-19 immune-dysregulated tissue environment, SARS-CoV-2 interactions with host microbiome/virome communities, clotting/coagulation dysregulation, dysfunctional brainstem/vagus nerve signaling, dysautonomia or autonomic dysfunction, ongoing activity of primed immune cells, and autoimmunity due to molecular mimicry between pathogen and host proteins. The individualized nature of PASC symptoms suggests that different therapeutic approaches may be required to best manage specific patients.