A Revisit to the Research Updates of Drugs, Vaccines, and Bioinformatics Approaches in Combating COVID-19 Pandemic

Study of Potential Blocking Peptides Targeting the SARS-CoV-2 RBD/hACE2 Interaction

BACKGROUND/OBJECTIVES

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, was declared a public health emergency in early 2020. The infection initiates when the receptor-binding domain (RBD) of the viral spike protein binds to human angiotensin-converting enzyme 2 (ACE2). Despite the success of vaccination efforts, the emergence of new variants highlights the ongoing need for treatments targeting these evolving strains. In silico methods previously identified peptides BP2, BP9, and BP11 as being capable of disrupting the RBD-ACE2 interaction, though their efficacy has not been experimentally validated until now.

METHODS

In this study, these peptides were recombinantly produced in the yeast Komagataella phaffii, and the activity was assessed in vitro using binding assays with multiple RBD variants and the inhibition of the RBD-ACE2 interaction.

RESULTS

The production yield for BP2, BP9, and BP11 was 14.34, 4.01, and 1.35 mg per culture liter, respectively. Noteworthy, the three BPs interacted with the RBD of SARS-CoV-2 variants of concern, with BP2 showing higher recognition. Finally, the BPs showed an RBD/hACE2 interaction blocking capacity with IC50 values between 1.03 and 5.35 nM, with BP2 showing the lowest values among the evaluated peptides.

CONCLUSIONS

These results demonstrate that BP2, specifically, is a promising candidate for the development of novel therapeutic interventions targeting SARS-CoV-2 and other coronaviruses that use hACE2 for cellular entry.

Single-cell RNA-seq public data reveal the gene regulatory network landscape of respiratory epithelial and peripheral immune cells in COVID-19 patients

Introduction

Infection with SARS-CoV-2 leads to coronavirus disease 2019 (COVID-19), which can result in acute respiratory distress syndrome and multiple organ failure. However, its comprehensive influence on pathological immune responses in the respiratory epithelium and peripheral immune cells is not yet fully understood.

Methods

In this study, we analyzed multiple public scRNA-seq datasets of nasopharyngeal swabs and peripheral blood to investigate the gene regulatory networks (GRNs) of healthy individuals and COVID-19 patients with mild/moderate and severe disease, respectively. Cell-cell communication networks among cell types were also inferred. Finally, validations were conducted using bulk RNA-seq and proteome data.

Results

Similar and dissimilar regulons were identified within or between epithelial and immune cells during COVID-19 severity progression. The relative transcription factors (TFs) and their targets were used to construct GRNs among different infection sites and conditions. Between respiratory epithelial and peripheral immune cells, different TFs tended to be used to regulate the activity of a cell between healthy individuals and COVID-19 patients, although they had some TFs in common. For example, XBP1, FOS, STAT1, and STAT2 were activated in both the epithelial and immune cells of virus-infected individuals. In contrast, severe COVID-19 cases exhibited activation of CEBPD in peripheral immune cells, while CEBPB was exclusively activated in respiratory epithelial cells. Moreover, in patients with severe COVID-19, although some inflammatory genes, such as S100A8/A9, were found to be upregulated in both respiratory epithelial and peripheral immune cells, their relative regulators can differ in terms of cell types. The cell-cell communication analysis suggested that epidermal growth factor receptor signaling among epithelia contributes to mild/moderate disease, and chemokine signaling among immune cells contributes to severe disease.

Conclusion

This study identified cell type- and condition-specific regulons in a wide range of cell types from the initial infection site to the peripheral blood, and clarified the diverse mechanisms of maladaptive responses to SARS-CoV-2 infection.

COVID Variants, Villain and Victory: A Bioinformatics Perspective

The SARS-CoV-2 virus, a novel member of the Coronaviridae family, is responsible for the viral infection known as Coronavirus Disease 2019 (COVID-19). In response to the urgent and critical need for rapid detection, diagnosis, analysis, interpretation, and treatment of COVID-19, a wide variety of bioinformatics tools have been developed. Given the virulence of SARS-CoV-2, it is crucial to explore the pathophysiology of the virus. We intend to examine how bioinformatics, in conjunction with next-generation sequencing techniques, can be leveraged to improve current diagnostic tools and streamline vaccine development for emerging SARS-CoV-2 variants. We also emphasize how bioinformatics, in general, can contribute to critical areas of biomedicine, including clinical diagnostics, SARS-CoV-2 genomic surveillance and its evolution, identification of potential drug targets, and development of therapeutic strategies. Currently, state-of-the-art bioinformatics tools have helped overcome technical obstacles with respect to genomic surveillance and have assisted in rapid detection, diagnosis, and delivering precise treatment to individuals on time.

Honeysuckle (Lonicera japonica) and Huangqi (Astragalus membranaceus) Suppress SARS-CoV-2 Entry and COVID-19 Related Cytokine Storm in Vitro

COVID-19 is threatening human health worldwide but no effective treatment currently exists for this disease. Current therapeutic strategies focus on the inhibition of viral replication or using anti-inflammatory/immunomodulatory compounds to improve host immunity, but not both. Traditional Chinese medicine (TCM) compounds could be promising candidates due to their safety and minimal toxicity. In this study, we have developed a novel in silico bioinformatics workflow that integrates multiple databases to predict the use of honeysuckle (Lonicera japonica) and Huangqi (Astragalus membranaceus) as potential anti-SARS-CoV-2 agents. Using extracts from honeysuckle and Huangqi, these two herbs upregulated a group of microRNAs including let-7a, miR-148b, and miR-146a, which are critical to reduce the pathogenesis of SARS-CoV-2. Moreover, these herbs suppressed pro-inflammatory cytokines including IL-6 or TNF-α, which were both identified in the cytokine storm of acute respiratory distress syndrome, a major cause of COVID-19 death. Furthermore, both herbs partially inhibited the fusion of SARS-CoV-2 spike protein-transfected BHK-21 cells with the human lung cancer cell line Calu-3 that was expressing ACE2 receptors. These herbs inhibited SARS-CoV-2 M^pro activity, thereby alleviating viral entry as well as replication. In conclusion, our findings demonstrate that honeysuckle and Huangqi have the potential to be used as an inhibitor of SARS-CoV-2 virus entry that warrants further in vivo analysis and functional assessment of miRNAs to confirm their clinical importance. This fast-screening platform can also be applied to other drug discovery studies for other infectious diseases.

Potential phytochemical inhibitors of SARS-CoV-2 helicase Nsp13: a molecular docking and dynamic simulation study

The SARS-CoV-2 helicase Nsp13 is a promising target for developing anti-COVID drugs. In the present study, we have identified potential natural product inhibitors of SARS-CoV-2 Nsp13 targeting the ATP-binding site using molecular docking and molecular dynamics (MD) simulations. MD simulation of the prepared crystal structure of SARS-CoV-2 Nsp13 was performed to generate an ensemble of structures of helicase Nsp13 capturing the conformational diversity of the ATP-binding site. A natural product library of more than 14,000 phytochemicals from Indian medicinal plants was used to perform virtual screening against the ensemble of Nsp13 structures. Subsequently, a two-stage filter, first based on protein-ligand docking binding energy value and second based on protein residues in the ligand-binding site and non-covalent interactions between the protein residues and the ligand in the best-docked pose, was used to identify 368 phytochemicals as potential inhibitors of SARS-CoV-2 helicase Nsp13. MD simulations of the top inhibitors complexed with protein were performed to confirm stable binding, and to compute MM-PBSA based binding energy. From among the 368 potential phytochemical inhibitors, the top identified potential inhibitors of SARS-CoV-2 helicase Nsp13 namely, Picrasidine M, (+)-Epiexcelsin, Isorhoeadine, Euphorbetin and Picrasidine N, can be taken up initially for experimental studies.

Biosynthetic studies through feeding experiments in Eclipta prostrata (L.) L. hairy roots

Eclipta prostrata (L.) L. is a medicinal plant of the Asteraceae family, and several extracts and isolated compounds of E. prostrata (L.) L. showed a wide range of biological activities such as antimicrobial, anticancer, hepatoprotective, neuroprotective, hair growth promoting activities, and more recently against covid-19. Eclipta prostrata (L.) L. hairy roots produce wedelolactone (WL), demethylwedelolactone (DWL) and 3,5-di-O-caffeoylquinic acid (3,5-diCQA), and there is no data in literature regarding biosynthetic pathways are involved. To verify the biosynthetic route, feeding experiments were carried out using sodium [2-¹³C]acetate, [3-¹³C]dl-phenylalanine, and ¹³C-labeled compounds (WL, DWL and 3,5-diCQA) were detected by ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry (HPLC-QTOF-MS). Analysis showed that the metabolic pathways operative of coumestans (WL and DWL) are derived from acetate and shikimate pathways, while that the phenylpropanoid (3,5-diCQA) biosynthesis is exclusively from shikimate pathway.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11240-022-02342-0.

Jasmonates promote enhanced production of bioactive caffeoylquinic acid derivative in Eclipta prostrata (L.) L. hairy roots

Eclipta prostrata (L.) L. is widely used in traditional medicine for treatment of hepatitis, poisoning from snake bites and viral infections. Pharmacological studies confirmed its antioxidant, anti-inflammatory and anticancer activities. The efficacy of E. prostrata (L.) L. extracts has been correlated to phenylpropanoids such as flavonoids, coumestans and caffeoylquinic acid derivatives. In this work, the production of wedelolactone, demethylwedelolactone and 3,5-di-O-caffeoylquinic acid (3,5-diCQA) in hairy root cultures of E. prostrata (L.) L. C19 clone was increased after addition of eliciting agents jasmonic acid (JA) or methyl jasmonate (MeJA) at multiple concentrations. Cultures elicited with 100 μM of JA saw a 5.2 fold increase in wedelolactone (from 0.72 to 3.72 mg/g d.w.), a 1.6 fold increase in demethylwedelolactone (from 5.54 to 9.04 mg/g d.w.) and a 2.47 fold increase in 3,5-diCQA (from 18.08 to 44.71 mg/g d.w.). Obtained data validate the potential of E. prostrata (L.) L. hairy root cultures as a production system of wedelolactone, demethylwedelolactone and especially 3,5-diCQA, which has recently been reported to possess activity against coronavirus disease (Covid-19) by in silico computational studies.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11240-021-02201-4.

Natural Bioactive Molecules: An Alternative Approach to the Treatment and Control of COVID-19

Several coronaviruses (CoVs) have been associated with serious health hazards in recent decades, resulting in the deaths of thousands around the globe. The recent coronavirus pandemic has emphasized the importance of discovering novel and effective antiviral medicines as quickly as possible to prevent more loss of human lives. Positive-sense RNA viruses with group spikes protruding from their surfaces and an abnormally large RNA genome enclose CoVs. CoVs have already been related to a range of respiratory infectious diseases possibly fatal to humans, such as MERS, SARS, and the current COVID-19 outbreak. As a result, effective prevention, treatment, and medications against human coronavirus (HCoV) is urgently needed. In recent years, many natural substances have been discovered with a variety of biological significance, including antiviral properties. Throughout this work, we reviewed a wide range of natural substances that interrupt the life cycles for MERS and SARS, as well as their potential application in the treatment of COVID-19.

A metabolic modeling approach reveals promising therapeutic targets and antiviral drugs to combat COVID-19

In this study we have developed a method based on Flux Balance Analysis to identify human metabolic enzymes which can be targeted for therapeutic intervention against COVID-19. A literature search was carried out in order to identify suitable inhibitors of these enzymes, which were confirmed by docking calculations. In total, 10 targets and 12 bioactive molecules have been predicted. Among the most promising molecules we identified Triacsin C, which inhibits ACSL3, and which has been shown to be very effective against different viruses, including positive-sense single-stranded RNA viruses. Similarly, we also identified the drug Celgosivir, which has been successfully tested in cells infected with different types of viruses such as Dengue, Zika, Hepatitis C and Influenza. Finally, other drugs targeting enzymes of lipid metabolism, carbohydrate metabolism or protein palmitoylation (such as Propylthiouracil, 2-Bromopalmitate, Lipofermata, Tunicamycin, Benzyl Isothiocyanate, Tipifarnib and Lonafarnib) are also proposed.