Coronavirus pathogenesis

Murine β-coronavirus spike protein: A major determinant of neuropathogenic properties

Coronaviruses have emerged as a significant challenge to human health. While earlier outbreaks of coronaviruses such as SARS-CoV and MERS-CoV posed serious threats, the recent SARS-CoV-2 pandemic has heightened interest in coronavirus research due to its pulmonary pathology, in addition to its neurological manifestations. In addition, the patients who have recovered from SARS-CoV-2 infection show long-term symptoms such as anosmia, brain fog and long COVID. A major hurdle in studying these viruses is the limited availability of specialized research facilities, emphasizing the need for prototype virus-based models to investigate the pathophysiology. The mouse hepatitis virus (MHV), a member of the β-coronavirus family, serves as an excellent model to unravel the mechanisms underlying virus-induced pathogenesis. This review highlights two decades of research efforts aimed at understanding the pathophysiological mechanism of coronavirus-induced diseases, focusing on the development of targeted recombinant strains to identify the minimal essential motif of the spike protein responsible for fusogenicity and neuropathogenicity. By synthesizing findings from these studies, the review identifies the most promising therapeutic targets against coronaviruses, paving the way for the development of pan-coronavirus antivirals.

Gut microbiota contributes to protection against porcine deltacoronavirus infection in piglets by modulating intestinal barrier and microbiome

BACKGROUND

Gut microbiota plays a critical role in counteracting enteric viral infection. Our previous study demonstrated that infection of porcine deltacoronavirus (PDCoV) disturbs gut microbiota and causes intestinal damage and inflammation in piglets. However, the influence of gut microbiota on PDCoV infection remains unclear.

RESULTS

Firstly, the relationship between gut microbiota and disease severity of PDCoV infection was evaluated using 8-day-old and 90-day-old pigs. The composition of gut microbiota was significantly altered in 8-day-old piglets after PDCoV infection, leading to severe diarrhea and intestinal damage. In contrast, PDCoV infection barely affected the 90-day-old pigs. Moreover, the diversity (richness and evenness) of microbiota in 90-day-old pigs was much higher compared to the 8-day-old piglets, suggesting the gut microbiota is possibly associated with the severity of PDCoV infection. Subsequently, transplanting the fecal microbiota from the 90-day-old pigs to the 3-day-old piglets alleviated clinical signs of PDCoV infection, modulated the diversity and composition of gut microbiota, and maintained the physical and chemical barrier of intestines. Additionally, metabolomic analysis revealed that the fecal microbiota transplantation (FMT) treatment upregulated the swine intestinal arginine biosynthesis, FMT significantly inhibited the inflammatory response in piglet intestine by modulating the TLR4/MyD88/NF-κB signaling pathway.

CONCLUSIONS

PDCoV infection altered the structure and composition of the gut microbiota in neonatal pigs. FMT treatment mitigated the clinical signs of PDCoV infection in the piglets by modulating the gut microbiota composition and intestinal barrier, downregulating the inflammatory response. The preventive effect of FMT provides novel targets for the development of therapeutics against enteropathogenic coronaviruses. Video Abstract.

Human coronaviruses: activation and antagonism of innate immune responses

SUMMARYHuman coronaviruses cause a range of respiratory diseases, from the common cold (HCoV-229E, HCoV-NL63, HCoV-OC43, and SARS-CoV-2) to lethal pneumonia (SARS-CoV, SARS-CoV-2, and MERS-CoV). Coronavirus interactions with host innate immune antiviral responses are an important determinant of disease outcome. This review compares the host's innate response to different human coronaviruses. Host antiviral defenses discussed in this review include frontline defenses against respiratory viruses in the nasal epithelium, early sensing of viral infection by innate immune effectors, double-stranded RNA and stress-induced antiviral pathways, and viral antagonism of innate immune responses conferred by conserved coronavirus nonstructural proteins and genus-specific accessory proteins. The common cold coronaviruses HCoV-229E and -NL63 induce robust interferon signaling and related innate immune pathways, SARS-CoV and SARS-CoV-2 induce intermediate levels of activation, and MERS-CoV shuts down these pathways almost completely.

A critical review on phytochemicals as antiviral medications for SARS-CoV-2 virus infection

A pandemic of acute respiratory infection, which was specified as coronavirus disease 2019, was instigated by a different strain of the virulent coronavirus SARS-CoV-2 that first appeared in late 2019. Since viral infections spread fast and there is presently no effective treatment, the use of plants with a long history of use in treating these infections has been explored regularly. The pandemic of coronavirus disease 2019 (COVID-19) has brought to light the dearth of medications with approval to treat acute viral illnesses. Because of this, the illness had a high fatality rate. The mortality rate was initially quite high and varied according to the patient's geographic location. For instance, among Chinese patients, the rate was 3·6%, whereas 1·5% of COVID-19-related deaths were documented outside of China. As of 2020, India has a 1.4% case fatality rate (CFR) of COVID-19 mortality, compared to 2.8% in Brazil and 1.8% in the USA. Many studies are being conducted to create pharmaceutical compounds specifically targeting important SARS-CoV-2 proteins. Several drug discovery initiatives are being undertaken to find powerful inhibitors by combining biochemical assay and computer-aided drug design techniques. Although plant-derived compounds have not had much success in the dominion of antivirals, plants are, however, believed to be a limitless supply of medications for a variety of diseases and clinical conditions. The scientific foundation required for developing novel natural source medications is provided by the chemical characterization and analysis of plant components. Most viral infections treated by ethnobotanical applications and historical literature on ayurveda, and traditional medicine are generally attributed to phytochemicals, which are compounds derived from medicinal plants. In this review, we have described the application of vascular plant-derived chemicals, such as tannins, polyphenols, alkaloids, and flavonoids, as antivirals, especially for managing COVID-19. This article discusses novel bioactive compounds and their molecular structures that target the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as prospective candidates for anti-coronavirus disease drugs. Moreover, to confirm the effectiveness of the phytochemicals that have demonstrated antiviral activity, clinical trials would need to be conducted in addition to the preclinical research that has already been done. To ensure spectacular findings, more applications of the compound would need to be studied to fully understand the effects of those phytochemicals whose clinical usefulness has already been established.

The effect of cysteine oxidation on conformational changes of SARS-CoV-2 spike protein using atomistic simulations

The SARS-CoV-2 Spike (S) protein plays a central role in viral entry into host cells, making it a key target for therapeutic interventions. Oxidative stress, often triggered during viral infections, can cause oxidation of cysteine in this protein. Here we investigate the impact of cysteine oxidation, specifically the formation of cysteic acid, on the conformational dynamics of the SARS-CoV-2 S protein using atomistic simulations. In particular, we examine how cysteine oxidation influences the transitions of the S protein's receptor-binding domain (RBD) between "down" (inaccessible) and "up" (accessible) states, which are critical for host cell receptor engagement. Using solvent-accessible surface area (SASA) analysis, we identify key cysteine residues susceptible to oxidation. The results of targeted molecular dynamics (TMD) and umbrella sampling (US) simulations reveal that oxidation reduces the energy barrier for RBD transitions by approximately 30 kJ mol-1, facilitating conformational changes and potentially enhancing viral infectivity. Furthermore, we analyze the interactions between oxidized cysteine residues and glycans, as well as alterations in hydrogen bonds and salt bridges. Our results show that oxidation disrupts normal RBD dynamics, influencing the energy landscape of conformational transitions. Our work provides novel insights into the role of cysteine oxidation in modulating the structural dynamics of the SARS-CoV-2 S protein, highlighting potential targets for antiviral strategies aimed at reducing oxidative stress or modifying post-translational changes. These findings contribute to a deeper understanding of viral infectivity and pathogenesis under oxidative conditions.

IFN-γ signaling is required for the efficient replication of murine hepatitis virus (MHV) strain JHM in the brains of infected mice

Neurotropic viruses are a major public health concern as they can cause encephalitis and other severe brain diseases. Many of these viruses, including flaviviruses, herpesviruses, rhabdoviruses and alphaviruses enter the brain through the olfactory neuroepithelium (ONE) in the olfactory bulbs (OB). Due to the low percentage of encephalitis that occurs following these infections, it's thought that the OBs have specialized innate immune responses to eliminate viruses. Murine hepatitis virus strain JHM (JHMV) is a model coronavirus that causes severe encephalitis in mice and can access the brain through olfactory sensory neurons. We've shown that a JHMV Mac1-mutant virus, N1347A, has decreased replication and disease in the brains of mice. Here we further show that this virus replicates poorly in the OB. However, it is unknown which innate immune factors restrict N1347A replication in the OB. RNA seq analysis of infected olfactory bulbs showed that IFNγ was upregulated in the OB while IFN-β was barely detectable at 5 days post-infection. To determine if IFN-γ restricts JHMV N1347A replication, we utilized IFN-γ and IFN-γ receptor (IFN-γR) knockout (KO) mice. Surprisingly we found that JHMV WT and N1347A replicated very poorly in the OB and whole brains of both IFN-γ and IFN-γR KO mice following intranasal infection, though survival and weight loss were unaltered. Furthermore, we determined that microglia were the primary cells producing IFN-γ during the early stages of this infection. We conclude that IFN-γ is required for the efficient replication of JHMV in the brains of infected mice.

Effects of immunoproteasome inhibition on acute respiratory infection with murine hepatitis virus strain 1

The immunoproteasome (IP) is a predominantly inducible component of the ubiquitin proteasome system that plays key roles in multiple aspects of immune function, inflammation, and protein homeostasis. We used murine hepatitis virus strain 1 (MHV-1), a mouse coronavirus, to define the role of IP activity during acute coronavirus respiratory infection. Expression of the β5i subunit of the IP and cytokines that induce IP activity, including IFN-γ, TNF-α, and IFN-β, increased in lungs and livers of CH3/HeJ mice following intranasal infection with MHV-1. IP inhibition using ONX-0914 did not affect MHV-1 replication in bone marrow-derived dendritic cells in vitro. IP inhibition in vivo exacerbated virus-induced weight loss and mortality but had no effect on virus replication in lungs or livers. IP inhibition had minimal effect on virus-induced pulmonary inflammation but led to substantially increased liver pathology, including greater upregulation of pro-inflammatory cytokines and histological evidence of inflammation and necrosis. Those findings were associated with evidence of increased endoplasmic reticulum stress although not with accumulation of ubiquitinated protein. Our results indicate that the IP is a protective host factor during acute MHV-1 infection.

IMPORTANCE

Inflammatory responses triggered by acute infection by respiratory viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) drive morbidity and mortality. Infection of mice with murine hepatitis virus strain 1 (MHV-1), a mouse coronavirus, is a useful model to study the pathogenesis of coronavirus respiratory infections. The immunoproteasome is an inducible component of the ubiquitin proteasome system that is poised to contribute to multiple aspects of immune function, inflammation, and protein homeostasis during an infection. We used the MHV-1 model to define the role of the immunoproteasome in coronavirus pathogenesis. We found that immunoproteasome subunit expression increases in the lungs and the liver during acute MHV-1 respiratory infection. Inhibition of immunoproteasome activity did not affect MHV-1 replication but increased MHV-1-induced weight loss, mortality, and inflammation in lungs and livers. Thus, our findings indicate that the immunoproteasome is a critical protective host factor during coronavirus respiratory infection.

Diverse bioactive secondary metabolites from Aspergillus terreus: antimicrobial, anticancer, and anti-SARS-CoV-2 activity studies

Owing to its high interest as prolific source of diverse bioactive compounds referred in our previous research work, we have scaled-up the fermentation of the marine Aspergillus terreus LGO13 on a liquid culture medium to isolate and identify the very minor/further promising bioactive secondary metabolites and to study their antibacterial, cytotoxic, and antiviral properties. Twenty-three known bioactive metabolites, including the recently discovered microbial natural product N-benzoyl-tryptophan (1), were obtained herein. Their structures were determined using HR-ESI-MS 1D/2D NMR spectroscopy and data from the literature. The biological properties of the microbial extract and the resulting compounds were examined using a set of microorganisms, cervix carcinoma KB-3-1, nonsmall cell lung cancer (NSCLC) A549, and coronavirus (SARS-CoV-2), respectively. Molecular docking (MD) simulations were used to investigate the potential targets of the separated metabolites as anti-SARS-CoV-2 drugs. According to the current study, a viral protein that may be the target of anticovid drugs is a papain-like protease (PLpro), and chaetominine (2) appears to be a viable choice against this protein. We evaluated the antiviral efficacy of chaetominine (2), fumitremorgin C (6), and azaspirofuran A (9) against SARS-CoV-2 based on MD data. Chaetominine (2) and azaspirofuran A (9) displayed intermediate selectivity indices (SI = 6.6 and 3.2, respectively), while fumitremorgin C (6) displayed a high selectivity index (SI = 19.77). These findings show that fumitremorgin C has promising antiviral action against SARS-CoV-2.

Navigating the COVID-19 Therapeutic Landscape: Unveiling Novel Perspectives on FDA-Approved Medications, Vaccination Targets, and Emerging Novel Strategies

Amidst the ongoing global challenge of the SARS-CoV-2 pandemic, the quest for effective antiviral medications remains paramount. This comprehensive review delves into the dynamic landscape of FDA-approved medications repurposed for COVID-19, categorized as antiviral and non-antiviral agents. Our focus extends beyond conventional narratives, encompassing vaccination targets, repurposing efficacy, clinical studies, innovative treatment modalities, and future outlooks. Unveiling the genomic intricacies of SARS-CoV-2 variants, including the WHO-designated Omicron variant, we explore diverse antiviral categories such as fusion inhibitors, protease inhibitors, transcription inhibitors, neuraminidase inhibitors, nucleoside reverse transcriptase, and non-antiviral interventions like importin α/β1-mediated nuclear import inhibitors, neutralizing antibodies, and convalescent plasma. Notably, Molnupiravir emerges as a pivotal player, now licensed in the UK. This review offers a fresh perspective on the historical evolution of COVID-19 therapeutics, from repurposing endeavors to the latest developments in oral anti-SARS-CoV-2 treatments, ushering in a new era of hope in the battle against the pandemic.

Reduction of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant infection by blocking the epidermal growth factor receptor (EGFR) pathway

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants presents challenges in global efforts to transition from the pandemic to an endemic stage. The spike protein of the SARS-CoV-2 virus, which is pivotal for cell entry, exhibits significant mutations in its variants, potentially affecting infectivity and therapeutic efficacy. Recent findings indicate upregulation of the epidermal growth factor receptor (EGFR) pathway, a key target in cancer therapy, by the spike protein of SARS-CoV-2. This study aimed to investigate the activity of the EGFR pathway against SARS-CoV-2 variants and to assess the inhibitory effects of EGFR inhibitors using SARS-CoV variant pseudoviral particles to guide future therapeutic strategies. Omicron variant SARS-CoV pseudoviral particles exhibited heightened infectivity in human angiotensin-converting enzyme 2 (hACE2)-expressing HEK293 and A549 lung cancer cells accompanied by increased EGFR pathway activation in infected cells. Using the EGFR tyrosine kinase inhibitor, osimertinib, we observed a reduction in viral infection rates in hACE2-HEK293 and A549 cells infected with the SARS-CoV-2 variant pseudoviral particles. We conducted further experiments to confirm that the reduction in infection efficacy with osimertinib treatment was not associated to a decrease in cell viability. Furthermore, this inhibitory effect of osimertinib in cell lines was corroborated in a spheroid cell culture model derived from hACE2-A549 cells. These findings suggest the potential application of EGFR-targeted antiviral therapy against highly infectious SARS-CoV-2 variants.IMPORTANCEThe emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is concerning as vaccines designed for one variant need not essentially protect against other novel variants. Therefore, there is an urgent need to identify therapies that can act against multiple novel variants that have heightened virulence compared with the wild type. It has been reported that the spike protein of the SARS-CoV-2 virus elicits an increased expression of the epidermal growth factor receptor (EGFR) pathway. We used this information and examined whether treatment with an EGFR inhibitor, osimertinib, which is already approved for clinical use in cancer therapy, can reduce the infection caused by SARS-CoV-2, wild type, and Omicron and Delta variants, in two cell lines and one spheroid model. The results showed that osimertinib treatment successfully reduced infection efficacy, particularly in variants, and that this effect was not related to a reduction in cell viability, making this a promising strategy for treating SARS-CoV-2 infections.

A multiantigenic Orf virus-based vaccine efficiently protects hamsters and nonhuman primates against SARS-CoV-2

Among the common strategies to design next-generation COVID-19 vaccines is broadening the antigenic repertoire thereby aiming to increase efficacy against emerging variants of concern (VoC). This study describes a new Orf virus-based vector (ORFV) platform to design a multiantigenic vaccine targeting SARS-CoV-2 spike and nucleocapsid antigens. Vaccine candidates were engineered, either expressing spike protein (ORFV-S) alone or co-expressing nucleocapsid protein (ORFV-S/N). Mono- and multiantigenic vaccines elicited comparable levels of spike-specific antibodies and virus neutralization in mice. Results from a SARS-CoV-2 challenge model in hamsters suggest cross-protective properties of the multiantigenic vaccine against VoC, indicating improved viral clearance with ORFV-S/N, as compared to equal doses of ORFV-S. In a nonhuman primate challenge model, vaccination with the ORFV-S/N vaccine resulted in long-term protection against SARS-CoV-2 infection. These results demonstrate the potential of the ORFV platform for prophylactic vaccination and represent a preclinical development program supporting first-in-man studies with the multiantigenic ORFV vaccine.

In Silico Identification of Potential Inhibitors of SARS-CoV-2 Main Protease (Mpro)

The ongoing Coronavirus Disease 19 (COVID-19) pandemic has had a profound impact on the global healthcare system. As the SARS-CoV-2 virus, responsible for this pandemic, continues to spread and develop mutations in its genetic material, new variants of interest (VOIs) and variants of concern (VOCs) are emerging. These outbreaks lead to a decrease in the efficacy of existing treatments such as vaccines or drugs, highlighting the urgency of new therapies for COVID-19. Therefore, in this study, we aimed to identify potential SARS-CoV-2 antivirals using a virtual screening protocol and molecular dynamics simulations. These techniques allowed us to predict the binding affinity of a database of compounds with the virus Mpro protein. This in silico approach enabled us to identify twenty-two chemical structures from a public database (QSAR Toolbox Ver 4.5 ) and ten promising molecules from our in-house database. The latter molecules possess advantageous qualities, such as two-step synthesis, cost-effectiveness, and long-lasting physical and chemical stability. Consequently, these molecules can be considered as promising alternatives to combat emerging SARS-CoV-2 variants.

Unraveling the structural and functional dimensions of SARS-CoV2 proteins in the context of COVID-19 pathogenesis and therapeutics

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) has emerged as the causative agent behind the global pandemic of Coronavirus Disease 2019 (COVID-19). As the scientific community strives to comprehend the intricate workings of this virus, a fundamental aspect lies in deciphering the myriad proteins it expresses. This knowledge is pivotal in unraveling the complexities of the viral machinery and devising targeted therapeutic interventions. The proteomic landscape of SARS-CoV2 encompasses structural, non-structural, and open-reading frame proteins, each playing crucial roles in viral replication, host interactions, and the pathogenesis of COVID-19. This comprehensive review aims to provide an updated and detailed examination of the structural and functional attributes of SARS-CoV2 proteins. By exploring the intricate molecular architecture, we have highlighted the significance of these proteins in viral biology. Insights into their roles and interplay contribute to a deeper understanding of the virus's mechanisms, thereby paving the way for the development of effective therapeutic strategies. As the global scientific community strives to combat the ongoing pandemic, this synthesis of knowledge on SARS-CoV2 proteins serves as a valuable resource, fostering informed approaches toward mitigating the impact of COVID-19 and advancing the frontier of antiviral research.

Identification of novel allosteric sites of SARS-CoV-2 papain-like protease (PLpro) for the development of COVID-19 antivirals

Coronaviruses such as SARS-CoV-2 encode a conserved papain-like protease (PLpro) that is crucial for viral replication and immune evasion, making it a prime target for antiviral drug development. In this study, three surface pockets on SARS-CoV-2 PLpro that may function as sites for allosteric inhibition were computationally identified. To evaluate the effects of these pockets on proteolytic activity, 52 residues were separately mutated to alanine. In Pocket 1, located between the Ubl and thumb domains, the introduction of alanine at T10, D12, T54, Y72, or Y83 reduced PLpro activity to <12% of that of WT. In Pocket 2, situated at the interface of the thumb, fingers, and palm domains, Q237A, S239A, H275A, and S278A inactivated PLpro. Finally, introducing alanine at five residues in Pocket 3, between the fingers and palm domains, inactivated PLpro: S212, Y213, Y251, K254, and Y305. Pocket 1 has a higher druggability score than Pockets 2 and 3. MD simulations showed that interactions within and between domains play critical roles in PLpro activity and thermal stability. The essential residues in Pockets 1 and 2 participate in a combination of intra- and inter-domain interactions. By contrast, the essential residues in Pocket three predominantly participate in inter-domain interactions. The most promising targets for therapeutic development are Pockets one and 3, which have the highest druggability score and the largest number of essential residues, respectively. Non-competitive inhibitors targeting these pockets may be antiviral agents against COVID-19 and related coronaviruses.

SARS-CoV-2 envelope protein alters calcium signaling via SERCA interactions

The clinical management of severe COVID-19 cases is not yet well resolved. Therefore, it is important to identify and characterize cell signaling pathways involved in virus pathogenesis that can be targeted therapeutically. Envelope (E) protein is a structural protein of the virus, which is known to be highly expressed in the infected host cell and is a key virulence factor; however, its role is poorly characterized. The E protein is a single-pass transmembrane protein that can assemble into a pentamer forming a viroporin, perturbing Ca2+ homeostasis. Because it is structurally similar to regulins such as, for example, phospholamban, that regulate the sarco/endoplasmic reticulum calcium ATPases (SERCA), we investigated whether the SARS-CoV-2 E protein affects the SERCA system as an exoregulin. Using FRET experiments we demonstrate that E protein can form oligomers with regulins, and thus can alter the monomer/multimer regulin ratio and consequently influence their interactions with SERCAs. We also confirm that a direct interaction between E protein and SERCA2b results in a decrease in SERCA-mediated ER Ca2+ reload. Structural modeling of the complexes indicates an overlapping interaction site for E protein and endogenous regulins. Our results reveal novel links in the host-virus interaction network that play an important role in viral pathogenesis and may provide a new therapeutic target for managing severe inflammatory responses induced by SARS-CoV-2.

Antiviral Activity of Graphene Oxide-Silver Nanocomposites Against Murine Betacoronavirus

Background

The high infectivity of coronaviruses has led to increased interest in developing new strategies to prevent virus spread. Silver nanoparticles (AgNPs) and graphene oxide (GO) have attracted much attention in the antiviral field. We investigated the potential antiviral activity of GO and AgNPs combined in the nanocomposite GO-Ag against murine betacoronavirus MHV using an in vitro model.

Methods

GO, AgNPs, and GO-Ag characterization (size distribution, zeta potential, TEM visualization, FT-IR, and EDX analysis) and XTT assay were performed. The antiviral activity of GO-Ag nanocomposites was evaluated by RT-qPCR and TCID50 assays. The results were compared with free AgNPs and pure GO. Cell growth and morphology of MHV-infected hepatocytes treated with GO-Ag composites were analyzed by JuLI™Br. Immunofluorescence was used to visualize the cell receptor used by MHV. Ultrastructural SEM analysis was performed to examine cell morphology after MHV infection and GO-Ag composite treatment.

Results

A significant reduction in virus titer was observed for all nanocomposites tested, ranging from 3.2 to 7.3 log10 TCID50. The highest titer reduction was obtained for GO 5 µg/mL - Ag 25 µg/mL in the post-treatment method. These results were confirmed by RT-qPCR analysis. The results indicate that GO-Ag nanocomposites exhibited better antiviral activity compared to AgNPs and GO. Moreover, the attachment of AgNPs to the GO flake platform reduced their cytotoxicity. In addition, the GO-Ag composite modulates the distribution of the Ceacam1 cell receptor and can modulate cell morphology.

Conclusion

Graphene oxide sheets act as a stabilizing agent, inhibiting the accumulation of AgNPs and reducing their cellular toxicity. The GO-Ag composite can physically bind and inhibit murine betacoronavirus from entering cells. Furthermore, the constant presence of GO-Ag can inhibit MHV replication and significantly limit its extracellular release. In conclusion, GO-Ag shows promise as an antiviral coating on solid surfaces to minimize virus transmission and spread.

Biochemical characterization of naturally occurring mutations in SARS-CoV-2 RNA-dependent RNA polymerase

Since the emergence of SARS-CoV-2, mutations in all subunits of the RNA-dependent RNA polymerase (RdRp) of the virus have been repeatedly reported. Although RdRp represents a primary target for antiviral drugs, experimental studies exploring the phenotypic effect of these mutations have been limited. This study focuses on the phenotypic effects of substitutions in the three RdRp subunits: nsp7, nsp8, and nsp12, selected based on their occurrence rate and potential impact. We employed nano-differential scanning fluorimetry and microscale thermophoresis to examine the impact of these mutations on protein stability and RdRp complex assembly. We observed diverse impacts; notably, a single mutation in nsp8 significantly increased its stability as evidenced by a 13°C increase in melting temperature, whereas certain mutations in nsp7 and nsp8 reduced their binding affinity to nsp12 during RdRp complex formation. Using a fluorometric enzymatic assay, we assessed the overall effect on RNA polymerase activity. We found that most of the examined mutations altered the polymerase activity, often as a direct result of changes in stability or affinity to the other components of the RdRp complex. Intriguingly, a combination of nsp8 A21V and nsp12 P323L mutations resulted in a 50% increase in polymerase activity. To our knowledge, this is the first biochemical study to demonstrate the impact of amino acid mutations across all components constituting the RdRp complex in emerging SARS-CoV-2 subvariants.

The Role of Coronavirus Spike Protein in Inducing Optic Neuritis in Mice: Parallels to the SARS-CoV-2 Virus

BACKGROUND

Optic neuritis (ON), one of the clinical manifestations of the human neurological disease multiple sclerosis (MS), was also reported in patients with COVID-19 infection, highlighting one potential neurological manifestation of SARS-CoV-2. However, the mechanism of ON in these patients is poorly understood.

EVIDENCE ACQUISITION

Insight may be gained by studying the neurotropic mouse hepatitis virus (MHV-A59), a β-coronavirus that belongs to the same family as SARS-CoV-2.

RESULTS

Mouse hepatitis virus-A59, or its isogenic spike protein recombinant strains, inoculation in mice provides an important experimental model to understand underpinning mechanisms of neuroinflammatory demyelination in association with acute stage optic nerve inflammation and chronic stage optic nerve demyelination concurrent with axonal loss. Spike is a surface protein that mediates viral binding and entry into host cells, as well as cell-cell fusion and viral spread. Studies have implicated spike-mediated mechanisms of virus-induced neuroinflammatory demyelination by comparing naturally occurring demyelinating (DM) and nondemyelinating (NDM) MHV strains.

CONCLUSIONS

Here, we summarize findings in MHV-induced experimental ON and myelitis, using natural DM and NDM strains as well as engineered recombinant strains of MHV to understand the role of spike protein in inducing ON and demyelinating disease pathology. Potential parallels in human coronavirus-mediated ON and demyelination, and insight into potential therapeutic strategies, are discussed.

Hyperforin, the major metabolite of St. John's wort, exhibits pan-coronavirus antiviral activity

Introduction

The COVID-19 pandemic caused by the SARS-CoV-2 virus has underscored the urgent necessity for the development of antiviral compounds that can effectively target coronaviruses. In this study, we present the first evidence of the antiviral efficacy of hyperforin, a major metabolite of St. John's wort, for which safety and bioavailability in humans have already been established.

Methods

Antiviral assays were conducted in cell culture with four human coronaviruses: three of high virulence, SARS-CoV-2, SARS-CoV, and MERS-CoV, and one causing mild symptoms, HCoV-229E. The antiviral activity was also evaluated in human primary airway epithelial cells. To ascertain the viral step inhibited by hyperforin, time-of-addition assays were conducted. Subsequently, a combination assay of hyperforin with remdesivir was performed.

Results

The results demonstrated that hyperforin exhibited notable antiviral activity against the four tested human coronaviruses, with IC50 values spanning from 0.24 to 2.55 µM. Kinetic studies indicated that the observed activity occur at a post-entry step, potentially during replication. The antiviral efficacy of hyperforin was additionally corroborated in human primary airway epithelial cells. The results demonstrated a reduction in both intracellular and extracellular SARS-CoV-2 viral RNA, confirming that hyperforin targeted the replication step. Finally, an additive antiviral effect on SARS-CoV-2 was observed when hyperforin was combined with remdesivir.

Discussion

In conclusion, hyperforin has been identified as a novel pan-coronavirus inhibitor with activity in human primary airway epithelial cells, a preclinical model for coronaviruses. These findings collectively suggest that hyperforin has potential as a candidate antiviral agent against current and future human coronaviruses.

Development of two novel on-site detection visualization methods for murine hepatitis virus based on the multienzyme isothermal rapid amplification

Murine hepatitis virus (MHV) infection is one of the most prevalent types of mice infection in laboratory. MHV could cause death in mice and even interfere with the results in animal experiments. Herein, we developed two isothermal approaches based on the Multienzyme Isothermal Rapid Amplification (MIRA), for rapid detection of MHV in conserved M gene. We designed and screened several pairs of primers and probes and the isothermal fluorescence detector was applied for the exonuclease Ⅲ reverse transcription MIRA (exo-RT-MIRA) assay. To further simplify the workflow, the portable fluorescence visualization instrument, also as a palm-sized handheld system, was used for the naked-eye exo-RT-MIRA assay. The amplification temperature and time were optimized. The assay could be processed well at 42 °C 20 min for the exo-RT-MIRA and the naked-eye exo-RT-MIRA assay. The limit of detection (LoD) of the exo-RT-MIRA assay was 43.4 copies/μL. The LoD of the naked-eye exo-RT-MIRA assay was 68.2 copies/μL. No nonspecific amplifications were observed in the two assays. A total of 107 specimens were examined by qPCR and two assays developed. The experimental results statistical analysis demonstrated that the exo-RT-MIRA assay with the qPCR yielded sufficient agreement with a kappa value of 1.000 (p < 0.0001). The results also exhibited a good agreement (kappa value, 0.961) (p < 0.0001) between the naked-eye exo-RT-MIRA assay and the qPCR assay. In our study, the exo-RT-MIRA assay and the naked-eye exo-RT-MIRA assay presented the possibility of new methods in MHV point-of-testing diagnosis.

Investigation of Transmission and Evolution of PEDV Variants and Co-Infections in Northeast China from 2011 to 2022

Porcine epidemic diarrhea virus (PEDV) is a rapidly evolving virus that causes outbreaks in pig herds worldwide. Mutations in the S protein of PEDV have led to the emergence of new viral variants, which can reduce vaccine immunity against prevalent strains. To understand the infection and variation pattern of PEDV in China, an extensive epidemiological survey was conducted in northeast China from 2015 to 2022. The genetic diversity of enteroviruses co-infected with PEDV and the PEDV S gene was analyzed, common mutation patterns that may have led to changes in PEDV virulence and infectivity in recent years were identified, and structural changes in the surface of the S protein resulting from mutations in the PEDV S gene from 2011 to 2022 were reviewed. Of note, two distinct mutations in the emerging 2022 HEB strain were identified. These findings provide a basis for a better understanding of PEDV co-infection and genetic evolution in northeast China.

Allosteric Regulation and Inhibition of Coronavirus 3CLpro Revealed by HDX-MS

Coronavirus (CoV) infections have caused contagious and fatal respiratory diseases in humans worldwide. CoV 3-chymotrypsin-like proteases (3CLpro or Mpro) play an important role in viral maturation, and maintenance of their dimeric conformation is crucial for viral activity. Therefore, allosterically regulated dimerization of 3CLpro can be employed as a drug development target. Here, we investigated the allosteric regulatory mechanism of 3CLpro dimerization by using hydrogen/deuterium exchange coupled with mass spectrometry (HDX-MS) technology. We found that the FLAG tag directly coupled to the N-finger of 3CLpro significantly increased HDX kinetics at the dimer interface, and 3CLpro transformed from a dimer to a monomer. The 3CLpro mutants of SARS-CoV-2, which are monomeric, also exhibited increased deuterium exchange. Binding of the allosteric inhibitor Gastrodenol to most betacoronavirus 3CLpros led to increased allosteric deuterium exchange, resulting in the monomeric conformation of the CoV 3CLpro upon binding. Molecular dynamics (MD) simulation analysis further indicated the molecular mechanism of action of Gastrodenol on CoV 3CLpro: binding of Gastrodenol to SARS-CoV-2 3CLpro destroyed the hydrogen bond in the dimer interface. These results suggest that Gastrodenol may be a potential broad-spectrum anti-betacoronavirus drug.

GCN2 in Viral Defence and the Subversive Tactics Employed by Viruses

The recent SARS-CoV-2 pandemic and associated COVID19 disease illustrates the important role of viral defence mechanisms in ensuring survival and recovery of the host or patient. Viruses absolutely depend on the host's protein synthesis machinery to replicate, meaning that impeding translation is a powerful way to counteract viruses. One major approach used by cells to obstruct protein synthesis is to phosphorylate the alpha subunit of eukaryotic translation initiation factor 2 (eIF2α). Mammals possess four different eIF2α-kinases: PKR, HRI, PEK/PERK, and GCN2. While PKR is currently considered the principal eIF2α-kinase involved in viral defence, the other eIF2α-kinases have also been found to play significant roles. Unsurprisingly, viruses have developed mechanisms to counteract the actions of eIF2α-kinases, or even to exploit them to their benefit. While some of these virulence factors are specific to one eIF2α-kinase, such as GCN2, others target all eIF2α-kinases. This review critically evaluates the current knowledge of viral mechanisms targeting the eIF2α-kinase GCN2. A detailed and in-depth understanding of the molecular mechanisms by which viruses evade host defence mechanisms will help to inform the development of powerful anti-viral measures.

Efficiency of hospitals in COVID-19 era: a case study of an affected country

BACKGROUND

The COVID-19 pandemic has affected all aspects of human life and society and has damaged the global economy. Health systems and hospitals were not exempted from this situation. The performance of hospitals during the COVID-19 pandemic was affected by policies related to the pandemic and other factors. This study aimed to investigate hospital performance indicators such as admissions and revenue.

METHODS

The medical records of patients with selected orthopedic and general surgical diseases were studied in two government hospitals in the capital city of Urmia in the second quarter of 2019, with the same period in 2020. Data were extracted based on the number of medical records, including length of stay, hospitalization type, sex, age, insurance, number of deaths, and readmissions from the medical records department. Payment amounts were collected from the revenue department and Hospital Information System. Two performance indicators, two result indicators, and two control indicators were used. Mean disease-specific revenue, total revenue, length of stay, and bed occupancy rate were calculated for both periods. Data were analyzed using SPSS (version 16) and the Mann-Whitney statistical test.

RESULTS

2140 cases were studied in the two disease groups. An increase was observed in the number of hospitalizations and average length of stay during the pandemic. The mean disease-specific revenue in the quarter of 2020 was higher than in 2019. However, total revenue decreased, and the difference in the mean of total revenue was significant for the two years (P = 0.00) in teaching center. The number of readmissions remained unchanged throughout in the pandemic. The number of deaths due to general surgery diseases in 2020 compared to the same period in 2019 was associated with a relative increase.

CONCLUSIONS

The COVID-19 pandemic increased the slope of health care costs. The analysis of the studied variables as performance, result, and control indicators showed that hospitalization rate, bed occupancy rate, and total revenue followed a similar and decreasing pattern in the selected hospitals during the COVID-19 pandemic. Hospitals should adopt appropriate strategies so that, in conditions identical to the COVID-19 pandemic, their performance is accompanied by proper management of resources, efficiency, and minimal reduction in revenue.

Analysis of the expression of the Serpina1 gene in SARS-CoV-2 infection: study of a new biomarker

INTRODUCTION

The SERPINA1 gene encodes the protein Alpha-1 Antitrypsin (AAT1). Possible imbalances between the concentrations of proteases and antiproteases (AAT1) can lead to the development of serious pulmonary and extrapulmonary pathologies. In this work we study the importance of this possible imbalance in patients with COVID-19.

OBJECTIVES

To correlate the severity of the symptoms of SARS-COV-2 infection with the AAT1 concentrations at diagnosis of the disease.

METHODS

An observational, prospective, cross-sectional, non-interventional, analytical study was carried out where 181 cases with COVID-19 admitted to the "Lozano Blesa" University Clinical Hospital of Zaragoza were selected. The concentration of AAT1 was studied in all of them and this was correlated with the clinical aspects and biochemical parameters at hospital admission.

RESULTS

141 cases corresponded to patients with severe COVID and 40 patients with mild COVID. AAT1 levels were positively correlated with the days of hospitalization, severity, C-Reactive Protein, ferritin, admission to Intensive Care, and death, and presented a negative correlation with the number of lymphocytes/mm3. AAT1 concentrations higher than 237.5 mg/dL allowed the patient to be classified as "severe" (S72%; E78%) and 311.5 mg/dL were associated with the risk of admission to Intensive Care or Exitus (S67%; E79%).

CONCLUSIONS

Levels of the SERPINA1 gene expression product, AAT1, correlate with the severity of COVID-19 patients at diagnosis of the disease, being useful as a prognostic biomarker.

SARS-CoV-2 Omicron BA.1 Variant Infection of Human Colon Epithelial Cells

The Omicron variant of SARS-CoV-2, characterized by multiple subvariants including BA.1, XBB.1.5, EG.5, and JN.1, became the predominant strain in early 2022. Studies indicate that Omicron replicates less efficiently in lung tissue compared to the ancestral strain. However, the infectivity of Omicron in the gastrointestinal tract is not fully defined, despite the fact that 70% of COVID-19 patients experience digestive disease symptoms. Here, using primary human colonoids, we found that, regardless of individual variability, Omicron infects colon cells similarly or less effectively than the ancestral strain or the Delta variant. The variant induced limited type III interferon expression and showed no significant impact on epithelial integrity. Further experiments revealed inefficient cell-to-cell spread and spike protein cleavage in the Omicron spike protein, possibly contributing to its lower infectious particle levels. The findings highlight the variant-specific replication differences in human colonoids, providing insights into the enteric tropism of Omicron and its relevance to long COVID symptoms.

Machine Learning to Identify Critical Biomarker Profiles in New SARS-CoV-2 Variants

The global dissemination of SARS-CoV-2 resulted in the emergence of several variants, including Alpha, Alpha + E484K, Beta, and Omicron. Our research integrated the study of eukaryotic translation factors and fundamental components in general protein synthesis with the analysis of SARS-CoV-2 variants and vaccination status. Utilizing statistical methods, we successfully differentiated between variants in infected individuals and, to a lesser extent, between vaccinated and non-vaccinated infected individuals, relying on the expression profiles of translation factors. Additionally, our investigation identified common causal relationships among the translation factors, shedding light on the interplay between SARS-CoV-2 variants and the host's translation machinery.

COVID-19 Associated Cardiovascular Disease-Risks, Prevention and Management: Heart at Risk Due to COVID-19

The SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) virus and the resulting COVID-19 pandemic have had devastating and lasting impact on the global population. Although the main target of the disease is the respiratory tract, clinical outcomes, and research have also shown significant effects of infection on other organ systems. Of interest in this review is the effect of the virus on the cardiovascular system. Complications, including hyperinflammatory syndrome, myocarditis, and cardiac failure, have been documented in the context of COVID-19 infection. These complications ultimately contribute to worse patient outcomes, especially in patients with pre-existing conditions such as hypertension, diabetes, or cardiovascular disease (CVD). Importantly and interestingly, reports have demonstrated that COVID-19 also causes myocardial injury in adults without pre-existing conditions and contributes to systemic complications in pediatric populations, such as the development of multisystem inflammatory syndrome in children (MIS-C). Although there is still a debate over the exact mechanisms by which such complications arise, understanding the potential paths by which the virus can influence the cardiovascular system to create an inflammatory environment may clarify how SARS-CoV-2 interacts with human physiology. In addition to describing the mechanisms of disease propagation and patient presentation, this review discusses the diagnostic findings and treatment strategies and the evolution of management for patients presenting with cardiovascular complications, focusing on disease treatment and prevention.

Serpentoviruses Exhibit Diverse Organization and ORF Composition with Evidence of Recombination

Serpentoviruses are a subfamily of positive sense RNA viruses in the order Nidovirales, family Tobaniviridae, associated with respiratory disease in multiple clades of reptiles. While the broadest viral diversity is reported from captive pythons, other reptiles, including colubrid snakes, turtles, and lizards of captive and free-ranging origin are also known hosts. To better define serpentoviral diversity, eleven novel serpentovirus genomes were sequenced with an Illumina MiSeq and, when necessary, completed with other Sanger sequencing methods. The novel serpentoviral genomes, along with 57 other previously published serpentovirus genomes, were analyzed alongside four outgroup genomes. Genomic analyses included identifying unique genome templates for each serpentovirus clade, as well as analysis of coded protein composition, potential protein function, protein glycosylation sites, differences in phylogenetic history between open-reading frames, and recombination. Serpentoviral genomes contained diverse protein compositions. In addition to the fundamental structural spike, matrix, and nucleoprotein proteins required for virion formation, serpentovirus genomes also included 20 previously uncharacterized proteins. The uncharacterized proteins were homologous to a number of previously characterized proteins, including enzymes, transcription factors, scaffolding, viral resistance, and apoptosis-related proteins. Evidence for recombination was detected in multiple instances in genomes from both captive and free-ranging snakes. These results show serpentovirus as a diverse clade of viruses with genomes that code for a wide diversity of proteins potentially enhanced by recombination events.

Neurons cytoskeletal architecture remodeling during the replication cycle of mouse coronavirus MHV-JHM: a morphological in vitro study

Nowadays, the population is still struggling with a post-COVID19 syndrome known as long COVID, including a broad spectrum of neurological problems. There is an urgent need for a better understanding and exploration of the mechanisms of coronavirus neurotropism. For this purpose, the neurotropic strain of mouse hepatitis virus (MHV-JHM) originating from the beta-coronavirus genus, the same as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been used. The role of the cytoskeleton during virus replication in neurons in vitro was determined to understand the mechanisms of MHV-JHM neuroinfection. We have described for the first time the changes of actin filaments during MHV-JHM infection. We also observed productive replication of MHV-JHM in neurons during 168 h p.i. and syncytial cytopathic effect. We discovered that the MHV-JHM strain modulated neuronal cytoskeleton during infection, which were manifested by: (i) condensation of actin filaments in the cortical layer of the cytoplasm, (ii) formation of microtubule cisternae structures containing viral antigen targeting viral replication site (iii) formation of tunneling nanotubes used by MHV-JHM for intercellular transport. Additionally, we demonstrated that the use of cytoskeletal inhibitors have reduced virus replication in neurons, especially noscapine and nocodazole, the microtubule shortening factors.

A Narrative Overview of Coronavirus Infection: Clinical Signs and Symptoms, Viral Entry and Replication, Treatment Modalities, and Management

The global pandemic known as coronavirus disease (COVID-19) is causing morbidity and mortality on a daily basis. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV- -2) virus has been around since December 2019 and has infected a high number of patients due to its idiopathic pathophysiology and rapid transmission. COVID-19 is now deemed a newly identified "syndrome" condition since it causes a variety of unpleasant symptoms and systemic side effects following the pandemic. Simultaneously, it always becomes potentially hazardous when new variants develop during evolution. Its random viral etiology prevents accurate and suitable therapy. Despite the fact that multiple preclinical and research studies have been conducted to combat this lethal virus, and various therapeutic targets have been identified, the precise course of therapy remains uncertain. However, just a few drugs have shown efficacy in treating this viral infection in its early stages. Currently, several medicines and vaccinations have been licensed following clinical trial research, and many countries are competing to find the most potent and effective immunizations against this highly transmissible illness. For this narrative review, we used PubMed, Google Scholar, and Scopus to obtain epidemiological data, pre-clinical and clinical trial outcomes, and recent therapeutic alternatives for treating COVID-19 viral infection. In this study, we discussed the disease's origin, etiology, transmission, current advances in clinical diagnostic technologies, different new therapeutic targets, pathophysiology, and future therapy options for this devastating virus. Finally, this review delves further into the hype surrounding the SARS-CoV-2 illness, as well as present and potential COVID-19 therapies.

Analysis of the clinical characteristics in 18 patients with novel coronavirus pneumonia: Observational study

The aim of the present study was to analyze the clinical features, treatments, and short-term prognoses of 18 patients with novel coronavirus pneumonia (NCP) in order to provide reference for further clinical prevention and control of the epidemic. From January 29 to February 29, 2020, data from 18 patients with NCP who were positive for the 2019 novel coronavirus nucleic acid test were collected, and their clinical manifestations, laboratory tests, imaging features, and treatment protocols were analyzed retrospectively. From among the 18 patients with NCP, 9 (50%) were imported cases and 9 (50%) had contact histories with confirmed adult patients. Clinical classification was mainly of the normal type (16 cases, 88.9%). Fever and cough were common clinical symptoms, and the main laboratory indices were lymphocytopenia and leukocytopenia. The main imaging findings yielded ground-glass opacity in 12 cases (66.7%) and patchy opacity in 9 cases (50%). All 18 patients were treated with antiviral therapy and targeted treatment in accordance with their symptoms, returned negative nucleic acid tests (9-23 days) after their treatment, and were cured and discharged by March 5, 2020. During the early stages in Deyang, most patients with NCP were input cases; in the later stages, the main route of infection was close contact within the family. Close contact history in epidemiology, nucleic acid detection, and chest imaging were important references for diagnosis. Antiviral therapy resulted in good therapeutic effects. Adopting multi-departmental consultation and remote consultation in combination with traditional Chinese medicine treatment and psychological counseling may result in a good short-term prognosis.

The pleiotropic approach to coronavirus disease-19 pathogenesis: The impact of liver diseases associated host genetic variants

Coronavirus disease-2019 (COVID-19) is a novel multisystemic viral disease caused pandemic. The disease impact involves liver and associated systems. Undoubtedly, host genetic background influences the predisposition and prediction of infection. Variants among human populations might increase susceptibility or protect against severe outcomes. In this manner, rs738409 variant of patatin-like phospholipase domain-containing protein 3 gene appears to be protective in some populations in spite of its aggravating effect on non-alcoholic fatty liver diseases (NAFLDs) and steatohepatitis. DRB1*15:01 allele of human leukocyte antigen is associated with protective effect in European and Japanese populations. DRB1*03:01 contrarily increases the susceptibility of severe COVID-19 infection in European populations. rs1260326 in glucokinase regulatory protein gene, rs112875651 in tribbles homolog 1 gene, rs429358 in apolipoprotein 1, and rs58542926 in transmembrane 6 superfamily 2 alleles are found related with NAFLD and obesity; thus, hypercoagulability and severe COVID-19 outcomes. In chronic or acute liver diseases, comorbid syndromes are the key factors to explain increased severity. There might not be a direct association between the variant and severe COVID-19 infection. As it is concluded, there are genes and variants known and unknown yet to be studied to reveal the association with disease severity.

In silico drug repurposing carvedilol and its metabolites against SARS-CoV-2 infection using molecular docking and molecular dynamic simulation approaches

The pandemic of coronavirus disease 2019 (COVID-19) caused by the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a significant impact on the economy and public health worldwide. Therapeutic options such as drugs and vaccines for this newly emerged disease are eagerly desired due to the high mortality. Using the U.S. Food and Drug Administration (FDA) approved drugs to treat a new disease or entirely different diseases, in terms of drug repurposing, minimizes the time and cost of drug development compared to the de novo design of a new drug. Drug repurposing also has some other advantages such as reducing safety evaluation to accelerate drug application on time. Carvedilol, a non-selective beta-adrenergic blocker originally designed to treat high blood pressure and manage heart disease, has been shown to impact SARS-CoV-2 infection in clinical observation and basic studies. Here, we applied computer-aided approaches to investigate the possibility of repurposing carvedilol to combat SARS-CoV-2 infection. The molecular mechanisms and potential molecular targets of carvedilol were identified by evaluating the interactions of carvedilol with viral proteins. Additionally, the binding affinities of in vivo metabolites of carvedilol with selected targets were evaluated. The docking scores for carvedilol and its metabolites with RdRp were - 10.0 kcal/mol, - 9.8 kcal/mol (1-hydroxyl carvedilol), - 9.7 kcal/mol (3-hydroxyl carvedilol), - 9.8 kcal/mol (4-hydroxyl carvedilol), - 9.7 kcal/mol (5-hydroxyl carvedilol), - 10.0 kcal/mol (8-hydroxyl carvedilol), and - 10.1 kcal/mol (O-desmethyl carvedilol), respectively. Using the molecular dynamics simulation (100 ns) method, we further confirmed the stability of formed complexes of RNA-dependent RNA polymerase (RdRp) and carvedilol or its metabolites. Finally, the drug-target interaction mechanisms that contribute to the complex were investigated. Overall, this study provides the molecular targets and mechanisms of carvedilol and its metabolites as repurposed drugs to fight against SARS-CoV-2 infection.

Role of Metals on SARS-CoV-2 Infection: a Review of Recent Epidemiological Studies

PURPOSE OF REVIEW

Metals and metalloids are known for their nutritional as well as toxic effects in humans. In the context of the SARS-CoV-2 pandemic, understanding the role of metals on COVID-19 infection is becoming important due to their role in infectious diseases. During the past 2 years, a significant number of studies have examined the impact of metals and metalloids on COVID-19 morbidity and mortality. We conducted a systematic review of peer-reviewed manuscripts on the association of metals and metalloids with SARS-CoV-2 infection and COVID-19 severity published since the onset of the pandemic.

RECENT FINDINGS

We searched for epidemiological studies available through the PubMed database published from January 2020 to December 2022. Of 92 studies identified, 20 met our inclusion criteria. These articles investigated the association of zinc (Zn), iron (Fe), selenium (Se), manganese (Mn), cadmium (Cd), arsenic (As), copper (Cu), magnesium (Mg), chromium (Cr), and/or lead (Pb) levels on SARS-CoV-2 infection and/or COVID-19 severity. Of the ten metals and metalloids of interest that reported either positive, negative, or no associations, Zn yielded the highest number of articles (n = 13), followed by epidemiological studies on Se (n = 7) and Fe (n = 5). Elevated serum Zn and Se were associated with reduced COVID-19 severity and mortality. Similarly, higher levels of serum Fe were associated with lower levels of cellular damage and symptoms of SARS-CoV-2 infection and with faster recovery from COVID-19. On the other hand, higher serum and urinary Cu and serum Mg levels were associated with higher COVID-19 severity and mortality. Along with the positive or negative effects, some studies reported no impact of metals on SARS-CoV-2 infection. This systematic review suggests that metals, particularly Zn, Fe, and Se, may help reduce the severity of COVID-19, while Cu and Mg may aggravate it. Our review suggests that future pandemic mitigation strategies may evaluate the role of Zn, Se, and Fe as potential therapeutic interventions.

Novel pseudonucleosides and sulfamoyl-oxazolidinone β-D-glucosamine derivative as anti-COVID-19: design, synthesis, and in silico study

New pseudonucleosides containing cyclic sulfamide moiety and sulfamoyl β-D-glucosamine derivative are described. These pseudonucleosides are synthesized in good yields starting from chlorosulfonyl isocyanate and β-D-glucosamine hydrochloride in five steps; (protection, acetylation, removal of the Boc group, sulfamoylation, and cyclization). Further, novel glycosylated sulfamoyloxazolidin-2-one is prepared in three steps; carbamoylation, sulfamoylation, and intramolecular cyclization. The structures of the synthesized compounds were confirmed by usual spectroscopic and spectrometric methods NMR, IR, MS, and EA. Interesting molecular docking of the prepared pseudonucleosides and (Beclabuvir, Remdesivir) drugs with SARS-CoV-2/Mpro (PDB:5R80) was conducted using the same parameters for a fair comparison. A low binding affinity of the synthesized compounds compared to the Beclabuvir and other analysis showed that pseudonucleosides have the ability to inhibit SARS-CoV-2. After the motivating results of molecular docking study, the complex between the SARS-CoV-2 Mpro and compound 7 was subjected to 100 ns molecular dynamics (MD) simulation using Desmond module of Schrodinger suite, during which the receptor-ligand complex showed substantial stability after 10 ns of MD simulation. Also, we studied the prediction of absorption, distribution, properties of metabolism, excretion, and toxicity (ADMET) of the synthesized compounds.Communicated by Ramaswamy H. Sarma.

Separation and quantification of Azvudine in plasma of patients with COVID-19 using LC-MS/MS

Azvudine (FNC) is a new drug conditionally approved in 2022 for the treatment of coronavirus disease 2019 (COVID-19) in China. However, the exposure level of FNC in COVID-19 patients in clinical practice is still obscure, and there is no liquid chromatography-tandem mass spectrometry (LC-MS/MS) or LC method reported for quantifying the FNC. In this study, a simple, fast, and reliable LC-MS/MS method using L-phenylalanine-D5 (Phe-D5) as the internal standard (IS) was developed for the quantification of FNC in plasma from COVID-19 patients. After simple protein precipitation with methanol, the analyte in the supernatant was separated on Waters Atlantis® T3 (2.1 ×100 mm, 3.0 µm) column with the mobile phase consisting of acetonitrile (ACN) - aqueous solution (containing 0.03% heptafluorobutyric acid and 0.2% formic acid). The mobile phase was delivered at 0.3 mL/min in an isocratic elution program (15:85, V: V). The linear relationship of FNC was good within the calibration range of 2.0 - 2000.0 ng/mL, with the recovery of FNC ranging from 81.37% to 103.31% and the matrix effect was 94.77%- 109.83%. The short-term, long-term, and freeze-thaw stability of the FNC assessed in method was acceptable, and all other items met the requirements of validation of the biological analytical method. Finally, the method was applied to detect the exposure level of FNC in plasma samples from patients diagnosed with COVID-19, and the results, which are within the linear range of the method, showed huge inter-individual variation, supporting the significance of therapeutic drug monitoring of FNC.

A novel recombinant S-based subunit vaccine induces protective immunity against porcine deltacoronavirus challenge in piglets

IMPORTANCE

As an emerging porcine enteropathogenic coronavirus that has the potential to infect humans, porcine deltacoronavirus (PDCoV) is receiving increasing attention. However, no effective commercially available vaccines against this virus are available. In this work, we designed a spike (S) protein and receptor-binding domain (RBD) trimer as a candidate PDCoV subunit vaccine. We demonstrated that S protein induced more robust humoral and cellular immune responses than the RBD trimer in mice. Furthermore, the protective efficacy of the S protein was compared with that of inactivated PDCoV vaccines in piglets and sows. Of note, the immunized piglets and suckling pig showed a high level of NAbs and were associated with reduced virus shedding and mild diarrhea, and the high level of NAbs was maintained for at least 4 months. Importantly, we demonstrated that S protein-based subunit vaccines conferred significant protection against PDCoV infection.

A suitable model to investigate acute neurological consequences of coronavirus infection

OBJECTIVE AND DESIGN

The present study aimed to investigate the neurochemical and behavioral effects of the acute consequences after coronavirus infection through a murine model.

MATERIAL

Wild-type C57BL/6 mice were infected intranasally (i.n) with the murine coronavirus 3 (MHV-3).

METHODS

Mice underwent behavioral tests. Euthanasia was performed on the fifth day after infection (5 dpi), and the brain tissue was subjected to plaque assays for viral titration, ELISA, histopathological, immunohistochemical and synaptosome analysis.

RESULTS

Increased viral titers and mild histological changes, including signs of neuronal degeneration, were observed in the cerebral cortex of infected mice. Importantly, MHV-3 infection induced an increase in cortical levels of glutamate and calcium, which is indicative of excitotoxicity, as well as increased levels of pro-inflammatory cytokines (IL-6, IFN-γ) and reduced levels of neuroprotective mediators (BDNF and CX3CL1) in the mice brain. Finally, behavioral analysis showed impaired motor, anhedonia-like and anxiety-like behaviors in animals infected with MHV-3.

CONCLUSIONS

In conclusion, the data presented emulate many aspects of the acute neurological outcomes seen in patients with COVID-19. Therefore, this model may provide a preclinical platform to study acute neurological sequelae induced by coronavirus infection and test possible therapies.

An Overview of SARS-CoV-2 Etiopathogenesis and Recent Developments in COVID-19 Vaccines

The Coronavirus disease-2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has significantly impacted the health and socioeconomic status of humans worldwide. Pulmonary infection of SARS-CoV-2 results in exorbitant viral replication and associated onset of inflammatory cytokine storm and disease pathology in various internal organs. However, the etiopathogenesis of SARS-CoV-2 infection is not fully understood. Currently, there are no targeted therapies available to cure COVID-19, and most patients are treated empirically with anti-inflammatory and/or anti-viral drugs, based on the disease symptoms. Although several types of vaccines are currently implemented to control COVID-19 and prevent viral dissemination, the emergence of new variants of SARS-CoV-2 that can evade the vaccine-induced protective immunity poses challenges to current vaccination strategies and highlights the necessity to develop better and improved vaccines. In this review, we summarize the etiopathogenesis of SARS-CoV-2 and elaborately discuss various types of vaccines and vaccination strategies, focusing on those vaccines that are currently in use worldwide to combat COVID-19 or in various stages of clinical development to use in humans.

Neuromuscular defects after infection with a beta coronavirus in mice

COVID-19 affects primarily the lung. However, several other systemic alterations, including muscle weakness, fatigue and myalgia have been reported and may contribute to the disease outcome. We hypothesize that changes in the neuromuscular system may contribute to the latter symptoms observed in COVID-19 patients. Here, we showed that C57BL/6J mice inoculated intranasally with the murine betacoronavirus hepatitis coronavirus 3 (MHV-3), a model for studying COVID-19 in BSL-2 conditions that emulates severe COVID-19, developed robust motor alterations in muscle strength and locomotor activity. The latter changes were accompanied by degeneration and loss of motoneurons that were associated with the presence of virus-like particles inside the motoneuron. At the neuromuscular junction level, there were signs of atrophy and fragmentation in synaptic elements of MHV-3-infected mice. Furthermore, there was muscle atrophy and fiber type switch with alteration in myokines levels in muscles of MHV-3-infected mice. Collectively, our results show that acute infection with a betacoronavirus leads to robust motor impairment accompanied by neuromuscular system alteration.

History, origin, transmission, genome structure, replication, epidemiology, pathogenesis, clinical features, diagnosis, and treatment of COVID-19: A review

In December, 2019, pneumonia triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surfaced in Wuhan, China. An acute respiratory illness named coronavirus disease 2019 (COVID-19) is caused by a new coronavirus designated as SARS-CoV-2. COVID-19 has surfaced as a major pandemic in the 21st century as yet. The entire world has been affected by this virus. World Health Organization proclaimed COVID-19 pandemic as a public health emergency of international concern on January 30, 2020. SARS-CoV-2 shares the same genome as coronavirus seen in bats. Therefore, bats might be its natural host of this virus. It primarily disseminates by means of the respiratory passage. Evidence revealed human-to-human transmission. Fever, cough, tiredness, and gastrointestinal illness are the manifestations in COVID-19-infected persons. Senior citizens are more vulnerable to infections which can lead to dangerous consequences. Various treatment strategies including antiviral therapies are accessible for the handling of this disease. In this review, we organized the most recent findings on COVID-19 history, origin, transmission, genome structure, replication, epidemiology, pathogenesis, clinical features, diagnosis, and treatment strategies.

Acute thrombotic occlusion involving three coronary arteries. A unique association with COVID-19 pneumonia

Key Clinical Message

Respiratory viruses, particularly COVID-19, can be associated with severe cases of myocardial infarction (MI). Physicians should have a low threshold for MI in COVID-19 patients who present with persistent chest pain as MI in rapidly deteriorating cases can be missed. Prompt response includes both timely diagnosis and swift treatment.

Abstract

The coronavirus disease 2019 (COVID-19) is associated with coronary artery thrombosis. Many cases of single-vessel and few cases of two-vessel thrombosis were reported. Herein, we report a unique association in a middle-aged man diagnosed with COVID-19 and presented later with acute myocardial infarction causing cardiogenic shock. The patient was found to have three-vessel thrombosis.

Removal of senescent cells reduces the viral load and attenuates pulmonary and systemic inflammation in SARS-CoV-2-infected, aged hamsters

Older age is one of the strongest risk factors for severe COVID-19. In this study, we determined whether age-associated cellular senescence contributes to the severity of experimental COVID-19. Aged golden hamsters accumulate senescent cells in the lungs, and the senolytic drug ABT-263, a BCL-2 inhibitor, depletes these cells at baseline and during SARS-CoV-2 infection. Relative to young hamsters, aged hamsters had a greater viral load during the acute phase of infection and displayed higher levels of sequelae during the post-acute phase. Early treatment with ABT-263 lowered pulmonary viral load in aged (but not young) animals, an effect associated with lower expression of ACE2, the receptor for SARS-CoV-2. ABT-263 treatment also led to lower pulmonary and systemic levels of senescence-associated secretory phenotype factors and to amelioration of early and late lung disease. These data demonstrate the causative role of age-associated pre-existing senescent cells on COVID-19 severity and have clear clinical relevance.

Are Measles-Mumps-Rubella (MMR) Antibodies Friends or Foes for Covid-19 Disease?

Many factors have been implicated in the pathogenesis and severity of COVID-19 pandemic. A wide variation in the susceptibility for SARS-CoV-2 infection among different population, gender and age has been observed. Multiple studies investigated the relationship between the antibody's titre of previously vaccinated individuals and the susceptibility of coronavirus infection, to find a rapid effective therapy for this pandemic. This study focused on the association between measles-mumps-rubella (MMR) antibodies titre and the severity of COVID-19 infection. We aimed to investigate the correlation between the antibody's titre of MMR and the SARS-CoV-2 infection susceptibility and disease severity, in a cohort of COVID-19 Egyptian patients, compared to a control group. MMR antibody titre was measured using enzyme Linked Immune Sorbent Assay; (ELISA) for 136 COVID-19 patients and 44 healthy individuals, as control group. There were high levels of measles and mumps antibodies titer in the deteriorating cases, which could not protect from SARS-CoV-2 infection. However, the rubella antibodies might protect from SARS-CoV-2 infection, but once the infection occurs, it may aggravate the risk of case deterioration. MMR antibodies could be used as a guideline for COVID-19 symptom-severity and, in turn, may be considered as an economic prognostic marker used for early protection from multiple autoimmune organ failure.

Impact on Spine Surgery during the First Two Years of COVID-19 Pandemic: A Nationwide Study in South Korea

Since December 2019, the novel coronavirus (COVID-19) has infected people worldwide. Owing to its rapid spread, elective surgeries, including spine surgery, have been re-scheduled. We analyzed nationwide data to investigate changes in the volume of spine surgery during the first two years of the pandemic. Nationwide data from January 2016 to December 2021 were obtained. We compared the total number of patients who underwent spine surgery and related medical expenses before and during the COVID-19 pandemic. In February and September, the number of patients was significantly smaller compared to January and August, respectively. Despite the pandemic, the proportion of patients undergoing spine surgery for degenerative diseases in 2021 was the highest. In contrast, the proportions of patients undergoing spine surgery for tumors showed a continuous decrease from 2019 to 2021. Although the number of spine surgeries performed at tertiary hospitals was lowest in 2020, it was not significantly smaller than that in 2019.The number of patients who underwent spine surgery in March 2020, during the first outbreak, decreased compared to the previous month, which differed from the trend observed in the pre-COVID-19 period. However, as the pandemic continues, the impact of COVID-19 on spine surgery has become less evident.

The 21st century disaster: The COVID-19 epidemiology, risk factors and control

The 21st century will be indelible in the world as ruin of the outbreak of COVID-19 was arose in Wuhan, China has now spread all over the world, up to August 2020. This study was based on the factors affecting the epidemiology of this virus in human societies of global concern. We studied the articles published in journals on various aspects of nCoVID19. The Wikipedia and WHO situation reports have also been searched out for related information. Outcomes were followed up until 2020. The COVID-19 is a virus with pandemic potential which may continue to cause regular infection in human. The pandemic outbreak of COVID-19 threatened public health across the globe in form of system as reflected in the shape of emergency. Approximately 21 million humans are infected and 759,400 have lost their lives till 2020 in all over the world. We have described epidemiological features, reservoirs, transmission, incubation period, rate of fatality, management including recent clinical chemotherapeutic approach and preventive measurements and masses which are at risk of COVID19. This virus causes viral pneumonia when it attacks on respiratory system and multiple failure which can leads to life threatening complications. It is believed to be zoonotic importance although it is not clear from which animal and how it is transmitted. Zoonotic transmission of COVID-19 has not yet known by science. The current study will help to establish a baseline for early effective control of this rapidly spreading severe viral illness. The available data on COVID-19 indicates that older males with comorbidities would have been more infected, which can result in severe respiratory complications. Implementation of preventive measurements, investigation of proper chemotherapeutics and detection of cross species transmission agents must be ensured.

Antiviral Peptides Delivered by Chitosan-Based Nanoparticles to Neutralize SARS-CoV-2 and HCoV-OC43

The COVID-19 pandemic has made it clear that there is a crucial need for the design and development of antiviral agents that can efficiently reduce the fatality rate caused by infectious diseases. The fact that coronavirus mainly enters through the nasal epithelial cells and spreads through the nasal passage makes the nasal delivery of antiviral agents a promising strategy not only to reduce viral infection but also its transmission. Peptides are emerging as powerful candidates for antiviral treatments, showing not only a strong antiviral activity, but also improved safety, efficacy, and higher specificity against viral pathogens. Based on our previous experience on the use of chitosan-based nanoparticles to deliver peptides intra-nasally the current study aimed to explore the delivery of two-novel antiviral peptides making use of nanoparticles consisting of HA/CS and DS/CS. The antiviral peptides were chemically synthesized, and the optimal conditions for encapsulating them were selected through a combination of physical entrapment and chemical conjugation using HA/CS and DS/CS nanocomplexes. Finally, we evaluated the in vitro neutralization capacity against SARS-CoV-2 and HCoV-OC43 for potential use as prophylaxis or therapy.

In Vitro Characterization and Antiviral Susceptibility of Ophidian Serpentoviruses

Ophidian serpentoviruses, positive-sense RNA viruses in the order Nidovirales, are important infectious agents of both captive and free-ranging reptiles. Although the clinical significance of these viruses can be variable, some serpentoviruses are pathogenic and potentially fatal in captive snakes. While serpentoviral diversity and disease potential are well documented, little is known about the fundamental properties of these viruses, including their potential host ranges, kinetics of growth, environmental stability, and susceptibility to common disinfectants and viricides. To address this, three serpentoviruses were isolated in culture from three unique PCR-positive python species: Ball python (Python regius), green tree python (Morelia viridis), and Stimson's python (Antaresia stimsoni). A median tissue culture infectious dose (TCID50) was established to characterize viral stability, growth, and susceptibility. All isolates showed an environmental stability of 10-12 days at room temperature (20 °C). While all three viruses produced variable peak titers on three different cell lines when incubated at 32 °C, none of the viruses detectably replicated at 35 °C. All viruses demonstrated a wide susceptibility to sanitizers, with 10% bleach, 2% chlorhexidine, and 70% ethanol inactivating the virus in one minute and 7% peroxide and a quaternary ammonium solution within three minutes. Of seven tested antiviral agents, remdesivir, ribavirin, and NITD-008, showed potent antiviral activity against the three viruses. Finally, the three isolates successfully infected 32 unique tissue culture cell lines representing different diverse reptile taxa and select mammals and birds as detected by epifluorescent immunostaining. This study represents the first characterization of in vitro properties of growth, stability, host range, and inactivation for a serpentovirus. The reported results provide the basis for procedures to mitigate the spread of serpentoviruses in captive snake colonies as well as identify potential non-pharmacologic and pharmacologic treatment options for ophidian serpentoviral infections.

Structural and non-structural proteins in SARS-CoV-2: potential aspects to COVID-19 treatment or prevention of progression of related diseases

Coronavirus disease 2019 (COVID-19) is caused by a new member of the Coronaviridae family known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are structural and non-structural proteins (NSPs) in the genome of this virus. S, M, H, and E proteins are structural proteins, and NSPs include accessory and replicase proteins. The structural and NSP components of SARS-CoV-2 play an important role in its infectivity, and some of them may be important in the pathogenesis of chronic diseases, including cancer, coagulation disorders, neurodegenerative disorders, and cardiovascular diseases. The SARS-CoV-2 proteins interact with targets such as angiotensin-converting enzyme 2 (ACE2) receptor. In addition, SARS-CoV-2 can stimulate pathological intracellular signaling pathways by triggering transcription factor hypoxia-inducible factor-1 (HIF-1), neuropilin-1 (NRP-1), CD147, and Eph receptors, which play important roles in the progression of neurodegenerative diseases like Alzheimer's disease, epilepsy, and multiple sclerosis, and multiple cancers such as glioblastoma, lung malignancies, and leukemias. Several compounds such as polyphenols, doxazosin, baricitinib, and ruxolitinib could inhibit these interactions. It has been demonstrated that the SARS-CoV-2 spike protein has a stronger affinity for human ACE2 than the spike protein of SARS-CoV, leading the current study to hypothesize that the newly produced variant Omicron receptor-binding domain (RBD) binds to human ACE2 more strongly than the primary strain. SARS and Middle East respiratory syndrome (MERS) viruses against structural and NSPs have become resistant to previous vaccines. Therefore, the review of recent studies and the performance of current vaccines and their effects on COVID-19 and related diseases has become a vital need to deal with the current conditions. This review examines the potential role of these SARS-CoV-2 proteins in the initiation of chronic diseases, and it is anticipated that these proteins could serve as components of an effective vaccine or treatment for COVID-19 and related diseases. Video Abstract.