Omicron N501Y mutation among SARS-CoV-2 lineages: Insilico analysis of potent binding to tyrosine kinase and hypothetical repurposed medicine

New variants of COVID-19 (XBB.1.5 and XBB.1.16, the "Arcturus"): A review of highly questioned concerns, a brief comparison between different peaks in the COVID-19 pandemic, with a focused systematic review on expert recommendations for prevention, vaccination, and treatment measures in the general population and at-risk groups

INTRODUCTION

The COVID-19 pandemic has taken many forms and continues to evolve, now around the Omicron wave, raising concerns over the globe. With COVID-19 being declared no longer a "public health emergency of international concern (PHEIC)," the COVID pandemic is still far from over, as new Omicron subvariants of interest and concern have risen since January of 2023. Mainly with the XBB.1.5 and XBB.1.16 subvariants, the pandemic is still very much "alive" and "breathing."

METHODS

This review consists of five highly concerning questions about the current state of the COVID Omicron peak. We searched four main online databases to answer the first four questions. For the last one, we performed a systematic review of the literature, with keywords "Omicron," "Guidelines," and "Recommendations."

RESULTS

A total of 31 articles were included. The main symptoms of the current Omicron wave include a characteristically high fever, coughing, conjunctivitis (with itching eyes), sore throat, runny nose, congestion, fatigue, body ache, and headache. The median incubation period of the symptoms is shorter than the previous peaks. Vaccination against COVID can still be considered effective for the new subvariants.

CONCLUSION

Guidelines recommend continuation of personal protective measures, third and fourth dose boosters, along with administration of bivalent messenger RNA vaccine boosters. The consensus antiviral treatment is combination therapy using Nirmatrelvir and Ritonavir, and the consensus for pre-exposure prophylaxis is Tixagevimab and Cilgavimab combination. We hope the present paper raises awareness for the continuing presence of COVID and ways to lower the risks, especially for at-risk groups.

The BCL-2 inhibitor APG-2575 resets tumor-associated macrophages toward the M1 phenotype, promoting a favorable response to anti-PD-1 therapy via NLRP3 activation

The main challenges in the use of immune checkpoint inhibitors (ICIs) are ascribed to the immunosuppressive tumor microenvironment and the lack of sufficient infiltration of activated CD8+ T cells. Transforming the tumor microenvironment (TME) from "cold" to "hot" and thus more likely to potentiate the effects of ICIs is a promising strategy for cancer treatment. We found that the selective BCL-2 inhibitor APG-2575 can enhance the antitumor efficacy of anti-PD-1 therapy in syngeneic and humanized CD34+ mouse models. Using single-cell RNA sequencing, we found that APG-2575 polarized M2-like immunosuppressive macrophages toward the M1-like immunostimulatory phenotype with increased CCL5 and CXCL10 secretion, restoring T-cell function and promoting a favorable immunotherapy response. Mechanistically, we demonstrated that APG-2575 directly binds to NF-κB p65 to activate NLRP3 signaling, thereby mediating macrophage repolarization and the activation of proinflammatory caspases and subsequently increasing CCL5 and CXCL10 chemokine production. As a result, APG-2575-induced macrophage repolarization could remodel the tumor immune microenvironment, thus improving tumor immunosuppression and further enhancing antitumor T-cell immunity. Multiplex immunohistochemistry confirmed that patients with better immunotherapeutic efficacy had higher CD86, p-NF-κB p65 and NLRP3 levels, accompanied by lower CD206 expression on macrophages. Collectively, these data provide evidence that further study on APG-2575 in combination with immunotherapy for tumor treatment is required.

Computational analysis of target genes in monkeypox virus infection and potential therapeutic precursors

BACKGROUND

Monkeypox is an orthopoxvirus that is responsible for zoonotic infections in humans. The virus has recently spread rapidly and the WHO has listed it as an international public health emergency of concern.

RESEARCH DESIGN AND METHODS

Here, we used network analysis and gene enrichment protocols and analyzed datasets of MPXV infection that induced host cell gene expression list and subsequently mapped them against two herbal target gene lists which highlighted considerable coherence in pharmacological attributes with COVID-19. Molecular docking and simulation were performed for the screened compounds.

RESULTS

Our results identified β-carotene and kaempferol possessing tremendous ability against the MPXV PLD protein. Both compounds were subjected to each of 100 ns molecular dynamics simulation and were found native to the PLD pocket. MM-PB (GB) SA analyses indicated -25.4, -40.1 kcal/mol and -17.2, -26.4kcal/mol of ΔGbind to the active pocket of PLD. Our data suggest the adaptive nature of the MPXV PLD active pocket toward hydrophobic inhibitors.

CONCLUSION

These results will be of high importance for the viral researchers to be tested in wet lab settings in designing potential inhibitors.

Harringtonine: A more effective antagonist for Omicron variant

Fusion with host cell membrane is the main mechanism of infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we propose that a new strategy to screen small-molecule antagonists blocking SARS-CoV-2 membrane fusion. Using cell membrane chromatography (CMC), we found that harringtonine (HT) simultaneously targeted SARS-CoV-2 S protein and host cell surface TMPRSS2 expressed by the host cell, and subsequently confirmed that HT can inhibit membrane fusion. HT effectively blocked SARS-CoV-2 original strain entry with the IC50 of 0.217 μM, while the IC50 in delta variant decreased to 0.101 μM, the IC50 in Omicron BA.1 variant was 0.042 μM. Due to high transmissibility and immune escape, Omicron subvariant BA.5 has become the dominant strain of the SARS-CoV-2 virus and led to escalating COVID-19 cases, however, against BA.5, HT showed a surprising effectiveness. The IC50 in Omicron BA.5 was even lower than 0.0019 μM. The above results revealed the effect of HT on Omicron is very significant. In summary, we characterize HT as a small-molecule antagonist by direct targeting on the Spike protein and TMPRSS2.

Metal Ion-Peptide-Intermediated Ligand Transfer for Serum Detection of the Omicron Variant of SARS-Cov-2 in Echinococcosis Patients

A method is developed to electrochemically induce target-specific covalent capturing of the spike protein of SARS-Cov-2, forming a covalent peptide-protein complex fit for working with such complicated clinical samples. Specifically, peptide-coordinated copper ions can be electrochemically controlled to induce cross-linkage between certain amino acids on the peptide probe and the target protein. Therefore, target specificity can be tuned electrochemically, realizing highly specific targeting of the omicron S protein or broader specificity toward all variants of the virus. Using this method, with electrochemically catalyzed generation of signal-enhancing molecules, the sensitivity and covalent detection allow their application in both serum and fecal samples. These results may point to their possible use in screening new variants of the virus in the near future.

The spread of the omicron variant: Identification of knowledge gaps, virus diffusion modelling, and future research needs

The World Health Organization (WHO) recognised variant B.1.1.529 of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) as a variant of concern, termed "Omicron", on November 26, 2021. Its diffusion was attributed to its several mutations, which allow promoting its ability to diffuse worldwide and its capability in immune evasion. As a consequence, some additional serious threats to public health posed the risk to undermine the global efforts made in the last two years to control the pandemic. In the past, several works were devoted to discussing a possible contribution of air pollution to the SARS-CoV-2 spread. However, to the best of the authors' knowledge, there are still no works dealing with the Omicron variant diffusion mechanisms. This work represents a snapshot of what we know right now, in the frame of an analysis of the Omicron variant spread. The paper proposes the use of a single indicator, commercial trade data, to model the virus spread. It is proposed as a surrogate of the interactions occurring between humans (the virus transmission mechanism due to human-to-human contacts) and could be considered for other diseases. It allows also to explain the unexpected increase in infection cases in China, detected at beginning of 2023. The air quality data are also analyzed to evaluate for the first time the role of air particulate matter (PM) as a carrier of the Omicron variant diffusion. Due to emerging concerns associated with other viruses (such as smallpox-like virus diffusion in Europe and America), the proposed approach seems to be promising to model the virus spreading.

Genomic surveillance of SARS-CoV-2 strains circulating in Iran during six waves of the pandemic

Background

SARS-CoV-2 genomic surveillance is necessary for the detection, monitoring, and evaluation of virus variants, which can have increased transmissibility, disease severity, or other adverse effects. We sequenced 330 SARS-CoV-2 genomes during the sixth wave of the COVID pandemic in Iran and compared them with five previous waves, for identifying SARS-CoV-2 variants, the genomic behavior of the virus, and understanding its characteristics.

Methods

After viral RNA extraction from clinical samples collected during the COVID-19 pandemic, next generation sequencing was performed using the Nextseq and Nanopore platforms. The sequencing data were analyzed and compared with reference sequences.

Results

In Iran during the first wave, V and L clades were detected. The second wave was recognized by G, GH, and GR clades. Circulating clades during the third wave were GH and GR. In the fourth wave, GRY (alpha variant), GK (delta variant), and one GH clade (beta variant) were detected. All viruses in the fifth wave were in GK clade (delta variant). In the sixth wave, Omicron variant (GRA clade) was circulating.

Conclusions

Genome sequencing, a key strategy in genomic surveillance systems, helps to detect and monitor the prevalence of SARS-CoV-2 variants, monitor the viral evolution of SARS-CoV-2, identify new variants for disease prevention, control, and treatment, and also provide information for and conduct public health measures in this area. With this system, Iran could be ready for surveillance of other respiratory virus diseases besides influenza and SARS-CoV-2.

Androgen receptor, a possible anti-infective therapy target and a potent immune respondent in SARS-CoV-2 spike binding: a computational approach

BACKGROUND

Although androgen in gender disparity of COVID-19 has been implied, no direct link has been provided.

RESEARCH DESIGN AND METHODS

Here, we applied AlphaFold multimer, network and single cells database analyses to highlight specificity of Androgen receptor (AR) against spike receptor binding protein (RBD) of SARS-CoV-2.

RESULTS

LXXL motifs in spike RBD are essential for AR binding. RBD LXXA mutation complex with the AR depicting slightly reduced binding energy, as LXXLL motif usually mediates nuclear receptor binding to coregulators. Moreover, AR preferred to bind a LYRL motif in specificity and interaction interface, and showed reduced affinity against Omicron compared to other variants (alpha, beta, gamma, and delta). Importantly, RBD LYRL motif is a conserved antigenic epitope (9 residues) for T-cell response. Network analysis of AR-related genes against COVID-19 database showed T-cell signaling regulation, and CD8+ T-cell spatial location in AR+ single cells, which is consistent with the AR binding motif LYRL in epitope function.

CONCLUSIONS

We provided the potent mechanisms of AR binding to RBD linking to immune response and vaccination shift. AR could be an anti-infective therapy target for anti-Omicron new lineages.

SARSMutOnto: An Ontology for SARS-CoV-2 Lineages and Mutations

Mutations allow viruses to continuously evolve by changing their genetic code to adapt to the hosts they infect. It is an adaptive and evolutionary mechanism that helps viruses acquire characteristics favoring their survival and propagation. The COVID-19 pandemic declared by the WHO in March 2020 is caused by the SARS-CoV-2 virus. The non-stop adaptive mutations of this virus and the emergence of several variants over time with characteristics favoring their spread constitute one of the biggest obstacles that researchers face in controlling this pandemic. Understanding the mutation mechanism allows for the adoption of anticipatory measures and the proposal of strategies to control its propagation. In this study, we focus on the mutations of this virus, and we propose the SARSMutOnto ontology to model SARS-CoV-2 mutations reported by Pango researchers. A detailed description is given for each mutation. The genes where the mutations occur and the genomic structure of this virus are also included. The sub-lineages and the recombinant sub-lineages resulting from these mutations are additionally represented while maintaining their hierarchy. We developed a Python-based tool to automatically generate this ontology from various published Pango source files. At the end of this paper, we provide some examples of SPARQL queries that can be used to exploit this ontology. SARSMutOnto might become a 'wet bench' machine learning tool for predicting likely future mutations based on previous mutations.

SARS-CoV-2 Omicron and its current known unknowns: A narrative review

The emergence of the SARS-CoV-2 Omicron variant (B.1.1.529) has created great global distress. This variant of concern shows multiple sublineages, importantly B.1.1.529.1 (BA.1), BA.1 + R346K (BA.1.1), and B.1.1.529.2 (BA.2), each with unique properties. However, little is known about this new variant, specifically its sub-variants. A narrative review was conducted to summarise the latest findings on transmissibility, clinical manifestations, diagnosis, and efficacy of current vaccines and treatments. Omicron has shown two times higher transmission rates than Delta and above ten times more infectious than other variants over a similar period. With more than 30 mutations in the spike protein's receptor-binding domain, there is reduced detection by conventional RT-PCR and rapid antigen tests. Moreover, the two-dose vaccine effectiveness against Delta and Omicron variants was found to be approximately 21%, suggesting an urgent need for a booster dose to prevent the possibility of breakthrough infections. However, the current vaccines remain highly efficacious against severe disease, hospitalisation, and mortality. Japanese preliminary lab data elucidated that the Omicron sublineage BA.2 shows a higher illness severity than BA.1. To date, the clinical management of Omicron remains unchanged, except for monoclonal antibodies. Thus far, only Bebtelovimab could sufficiently treat all three sub-variants of Omicron. Further studies are warranted to understand the complexity of Omicron and its sub-variants. Such research is necessary to improve the management and prevention of Omicron infection.

Recent advances on human mpox

Mpox has been a concern of public health and travel caution. Using databases of WHO, CDC, google scholar, and PubMed, we searched recent literatures and reviewed the history, genomic mutation/evolution, host cell response pathways, regulation policy, vaccine and therapy development. Recent studies showed that current mpox has many genomic mutations related to regulation by APOBEC3. Current mpox has also been suggested to be associated with sexual transmission. Vaccination should be applied and anti-mpox drug should be urgently developed. More investigations are needed to ensure outbreak prevention.

Omicron variant: Current insights and future directions

The global COVID-19 outbreak has returned with the identification of the SARS-CoV-2 Omicron variant (B.1.1.529) after appearing to be persistently spreading for the more than past two years. In comparison to prior SARS-CoV-2 variants, this new variant revealed a significant amount of mutation. This novel variety may have a greater rate of transmissibility which might impede the effectiveness of current diagnostic equipment as well as vaccination efficacy and also impede immunotherapies (Antibody / monoclonal antibody based). WHO designated B.1.1.529 as a variant of concern on November 26, 2021, identified as Omicron. The Omicron variant transmission method and severity, on the other hand, are well defined. The global spread of Omicron, which has now seized many nations, has resulted in numerous speculations regarding its origin and degree of infectivity. The following sections will go over its potential for transmission, omicron structure, and impact on COVID-19 vaccines, how it is different from delta variant and diagnostics.

In-silico structural inhibition of ACE-2 binding site of SARS-CoV-2 and SARS-CoV-2 Omicron spike protein by lectin antiviral dyad system to treat COVID-19

Spike glycoprotein of SARS-CoV-2 binds ACE-2 receptors via its receptor-binding-domain (RBD) and mediates virus-to-host cell fusion. Recently emerged omicron variant of SARS-CoV-2 possess around 30 mutations in spike protein where N501Y tremendously increases viral infectivity and transmission. Lectins interact with glycoproteins and mediate innate immunity displaying antiviral, antibacterial and anticarcinogenic properties. In this study, we analysed the potential of lectin, and lectin-antibody (spike-specific) complex to inhibit the ACE-2 binding site of wild and N501Y mutated spike protein by utilizing in-silico molecular docking and simulation approach. Docking of lectin at reported ACE-2 binding spike-RBD residues displayed the ZDock scores of 1907 for wild and 1750 for N501Y mutated spike-RBD. Binding of lectin with antibody to form proposed dyad complex gave ZDock score of 1174 revealing stable binding. Docking of dyad complex with wild and N501Y mutated spike-RBD, at lectin and antibody individually, showed high efficiency binding hence, effective structural inhibition of spike-RBD. MD simulation of 100ns of each complex proved high stability of complexes with RMSD values ranging from 0.2 -1.5nm. Consistent interactions of lead ACE-2 binding spike residues with lectin during simulation disclosed efficient structural inhibition by lectin against formation of spike RBD-ACE-2 complex.Hence, lectins along with their ability to induce innate immunity against spike glycoprotein can structurally inhibit the spike-RBD when given as lectin-antibody dyad system and thus can be developed into a dual effect treatment against COVID-19. Moreover, the high binding specificity of this system with spike-RBD can be exploited for development of diagnostic and drug-delivery systems.

A Systematic Review on the Emergence of Omicron Variant and Recent Advancement in Therapies

With the ongoing COVID-19 pandemic, the emergence of the novel Omicron variant in November 2021 has created chaos around the world. Despite mass vaccination, Omicron has spread rapidly, raising concerns around the globe. The Omicron variant has a vast array of mutations, as compared to another variant of concern, with a total of 50 mutations, 30 of which are present on its spike protein alone. These mutations have led to immune escape and more transmissibility compared to other variants, including the Delta variant. A cluster of mutations (H655Y, N679K, and P681H) present in the Omicron spike protein could aid in transmission. Currently, no virus-specific data are available to predict the efficacy of the anti-viral and mAbs drugs. However, two monoclonal antibody drugs, Sotrovimab and Evusheld, are authorized for emergency use in COVID-19 patients. This virus is not fading away soon. The easiest solution and least expensive measure to fight against this pandemic are to follow the appropriate COVID-19 protocols. There is a need to strengthen the level of research for the development of potential vaccines and anti-viral drugs. It is also important to monitor and expand the genomic surveillance to keep track of the emergence of new variants, thus avoiding the spread of new diseases worldwide. This article highlights the emergence of the new SARS-CoV-2 variant of concern, Omicron (B.1.1.529), and the vast number of mutations in its protein. In addition, recent advancements in drugs approved by FDA to treat COVID patients have been listed and focused in this paper.

Protective antigenic epitopes revealed by immunosignatures after three doses of inactivated SARS-CoV-2 vaccine

Background

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) has infected millions of people around the world. Vaccination is a pillar in the strategy to control transmission of the SARS-CoV-2 spread. Immune responses to vaccination require elucidation.

Methods

The immune responses to vaccination with three doses of inactivated SARS-CoV-2 vaccine were followed in a cohort of 37 healthy adults (18–59 years old). Blood samples were collected at multiple time points and submitted to peptide array, machine learning modeling, and sequence alignment analyses, the results of which were used to generate vaccine-induced antibody-binding region (VIABR) immunosignatures (Registration number: ChiCTR2200058571).

Results

Antibody spectrum signals showed vaccination stimulated antibody production. Sequence alignment analyses revealed that a third vaccine dose generated a new highly represented VIABR near the A570D mutation, and the whole process of inoculation enhanced the VIABR near the N501Y mutation. In addition, the antigen conformational epitopes varied between short- and long-term samples. The amino acids with the highest scores in the short-term samples were distributed primarily in the receptor binding domain (RBD) and N-terminal domain regions of spike (S) protein, while in the long-term samples (12 weeks after the 2^nd dose), some new conformational epitopes (CEs) were localized to crevices within the head of the S protein trimer.

Conclusion

Protective antigenic epitopes were revealed by immunosignatures after three doses of inactivated SARS-CoV-2 vaccine inoculation. A third dose results in a new top-10 VIABR near the A570D mutation site of S protein, and the whole process of inoculation enhanced the VIABR near the N501Y mutation, thus potentially providing protection from strains that have gained invasion and immune escape abilities through these mutation.

Peimine inhibits variants of SARS-CoV-2 cell entry via blocking the interaction between viral spike protein and ACE2

Coronavirus disease 2019 (COVID-19) is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several vaccines against SARS-CoV-2 have been approved; however, variants of concern (VOCs) can evade vaccine protection. Therefore, developing small compound drugs that directly block the interaction between the viral spike glycoprotein and ACE2 is urgently needed to provide a complementary or alternative treatment for COVID-19 patients. We developed a viral infection assay to screen a library of approximately 126 small molecules and showed that peimine inhibits VOCs viral infections. In addition, a fluorescence resonance energy transfer (FRET) assay showed that peimine suppresses the interaction of spike and ACE2. Molecular docking analysis revealed that peimine exhibits a higher binding affinity for variant spike proteins and is able to form hydrogen bonds with N501Y in the spike protein. These results suggest that peimine, a compound isolated from Fritillaria, may be a potent inhibitor of SARS-CoV-2 variant infection. PRACTICAL APPLICATIONS: In this study, we identified a naturally derived compound of peimine, a major bioactive alkaloid extracted from Fritillaria, that could inhibit SARS-CoV-2 variants of concern (VOCs) viral infection in 293T/ACE2 and Calu-3 lung cells. In addition, peimine blocks viral entry through interruption of spike and ACE2 interaction. Moreover, molecular docking analysis demonstrates that peimine has a higher binding affinity on N501Y in the spike protein. Furthermore, we found that Fritillaria significantly inhibits SARS-CoV-2 viral infection. These results suggested that peimine and Fritillaria could be a potential functional drug and food for COVID-19 patients.

Methodology-Centered Review of Molecular Modeling, Simulation, and Prediction of SARS-CoV-2

Despite tremendous efforts in the past two years, our understanding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), virus-host interactions, immune response, virulence, transmission, and evolution is still very limited. This limitation calls for further in-depth investigation. Computational studies have become an indispensable component in combating coronavirus disease 2019 (COVID-19) due to their low cost, their efficiency, and the fact that they are free from safety and ethical constraints. Additionally, the mechanism that governs the global evolution and transmission of SARS-CoV-2 cannot be revealed from individual experiments and was discovered by integrating genotyping of massive viral sequences, biophysical modeling of protein-protein interactions, deep mutational data, deep learning, and advanced mathematics. There exists a tsunami of literature on the molecular modeling, simulations, and predictions of SARS-CoV-2 and related developments of drugs, vaccines, antibodies, and diagnostics. To provide readers with a quick update about this literature, we present a comprehensive and systematic methodology-centered review. Aspects such as molecular biophysics, bioinformatics, cheminformatics, machine learning, and mathematics are discussed. This review will be beneficial to researchers who are looking for ways to contribute to SARS-CoV-2 studies and those who are interested in the status of the field.

Omicron variant (B.1.1.529) of SARS-CoV-2: understanding mutations in the genome, S-glycoprotein, and antibody-binding regions

The Omicron variant has been detected in nearly 150 countries. We analyzed the mutational landscape of Omicron throughout the genome, focusing the S-glycoprotein. We also evaluated mutations in the antibody-binding regions and observed some important mutations overlapping those of previous variants including N501Y, D614G, H655Y, N679K, and P681H. Various new receptor-binding domain mutations were detected, including Q493K, G496S, Q498R, S477N, G466S, N440K, and Y505H. New mutations were found in the NTD (Δ143-145, A67V, T95I, L212I, and Δ211) including one new mutation in fusion peptide (D796Y). There are several mutations in the antibody-binding region including K417N, E484A, Q493K, Q498R, N501Y, and Y505H and several near the antibody-binding region (S477N, T478K, G496S, G446S, and N440K). The impact of mutations in regions important for the affinity between spike proteins and neutralizing antibodies was evaluated. Furthermore, we examined the effect of significant antibody-binding mutations (K417N, T478K, E484A, and N501Y) on antibody affinity, stability to ACE2 interaction, and possibility of amino acid substitution. All the four mutations destabilize the antibody-binding affinity. This study reveals future directions for developing neutralizing antibodies against the Omicron variant.

There is nothing exempt from the peril of mutation - The Omicron spike

The 2019 corona virus disease (COVID-19) has caused a global chaos, where a novel Omicron variant has challenged the healthcare system, followed by which it has been referred to as a variant of concern (VOC) by the World Health Organization (WHO), owing to its alarming transmission and infectivity rate. The large number of mutations in the receptor binding domain (RBD) of the spike protein is responsible for strengthening of the spike-angiotensin-converting enzyme 2 (ACE2) interaction, thereby explaining the elevated threat. This is supplemented by enhanced resistance of the variant towards pre-existing antibodies approved for the COVID-19 therapy. The manuscript brings into light failure of existing therapies to provide the desired effect, however simultaneously discussing the novel possibilities on the verge of establishing suitable treatment portfolio. The authors entail the risks associated with omicron resistance against antibodies and vaccine ineffectiveness on one side, and novel approaches and targets - kinase inhibitors, viral protease inhibitors, phytoconstituents, entry pathways - on the other. The manuscript aims to provide a holistic picture about the Omicron variant, by providing comprehensive discussions related to multiple aspects of the mutated spike variant, which might aid the global researchers and healthcare experts in finding an optimised solution to this pandemic.

In Silico Screening of Bioactive Compounds of Representative Seaweeds to Inhibit SARS-CoV-2 ACE2-Bound Omicron B.1.1.529 Spike Protein Trimer

Omicron is an emerging SARS-CoV-2 variant, evolved from the Indian delta variant B.1.617.2, which is currently infecting worldwide. The spike glycoprotein, an important molecule in the pathogenesis and transmissions of SARS-CoV-2 variants, especially omicron B.1.1.529, shows 37 mutations distributed over the trimeric protein domains. Notably, fifteen of these mutations reside in the receptor-binding domain of the spike glycoprotein, which may alter transmissibility and infectivity. Additionally, the omicron spike evades neutralization more efficiently than the delta spike. Most of the therapeutic antibodies are ineffective against the omicron variant, and double immunization with BioNTech-Pfizer (BNT162b2) might not adequately protect against severe disease induced by omicron B.1.1.529. So far, no efficient antiviral drugs are available against omicron. The present study identified the promising inhibitors from seaweed’s bioactive compounds to inhibit the omicron variant B.1.1.529. We have also compared the seaweed’s compounds with the standard drugs ceftriaxone and cefuroxime, which were suggested as beneficial antiviral drugs in COVID-19 treatment. Our molecular docking analysis revealed that caffeic acid hexoside (−6.4 kcal/mol; RMSD = 2.382 Å) and phloretin (−6.3 kcal/mol; RMSD = 0.061 Å) from Sargassum wightii (S. wightii) showed the inhibitory effect against the crucial residues ASN417, SER496, TYR501, and HIS505, which are supported for the inviolable omicron and angiotensin-converting enzyme II (ACE2) receptor interaction. Cholestan-3-ol, 2-methylene-, (3beta, 5 alpha) (CMBA) (−6.0 kcal/mol; RMSD = 3.074 Å) from Corallina officinalis (C. officinalis) manifested the strong inhibitory effect against the omicron RBD mutated residues LEU452 and ALA484, was magnificently observed as the essential residues in Indian delta variant B.1.617.2 previously. The standard drugs (ceftriaxone and cefuroxime) showed no or less inhibitory effect against RBD of omicron B.1.1.529. The present study also emphasized the pharmacological properties of the considered chemical compounds. The results could be used to develop potent seaweed-based antiviral drugs and/or dietary supplements to treat omicron B.1.1529-infected patients.