Metronidazole, acyclovir and tetrahydrobiopterin may be promising to treat COVID-19 patients, through interaction with interleukin-12.

COVID-19 patients have shown overexpressed serum levels of several pro-inflammatory cytokines, leading to a high mortality rate due to numerous complications. Also, previous studies demonstrated that the metronidazole (MTZ) administration reduced pro-inflammatory cytokines and improved the treatment outcomes for inflammatory disorders. However, the effect and mechanism of action of MTZ on cytokines have not been studied yet. Thus, the current study aimed to identify anti-cytokine therapeutics for the treatment of COVID-19 patients with cytokine storm. The interaction of MTZ with key cytokines was investigated using molecular docking studies. MTZ-analogues, and its structurally similar FDA-approved drugs were also virtually screened against interleukin-12 (IL-12). Moreover, their mechanism of inhibition regarding IL-12 binding to IL-12 receptor was investigated by measuring the change in volume and area. IL-12-metronidazole complex is found to be more stable than all other cytokines under study. Our study also revealed that the active sites of IL-12 are inhibited from binding to its target, IL-12 receptor, by modifying the position of the methyl and hydroxyl functional groups in MTZ. Three MTZ analogues, metronidazole phosphate, metronidazole benzoate, 1-[1-(2-Hydroxyethyl)-5-nitroimidazol-2-yl]-N-methylmethanimine-oxide, and two FDA-approved drugs acyclovir (ACV), and tetrahydrobiopterin (THB) were also found to prevent binding of IL-12 to IL-12 receptor similar to MTZ by changing the surface and volume of IL-12 upon IL-12-drug/ligand complex formation. According to the RMSD results, after 100 ns MD simulations of human IL-12-MTZ/ACV/THB drug complexes, it was also observed that each complex was swinging within a few Å compared to their corresponding docking poses, indicating that the docking poses were reliable. The current study demonstrates that three FDA-approved drugs, namely, metronidazole, acyclovir and tetrahydrobiopterin, are potential repurposable treatment options for overexpressed serum cytokines found in COVID-19 patients. Similar approach is also useful to develop therapeutics against other human disorders.

Comparative analysis of SARS-CoV-2 envelope viroporin mutations from COVID-19 deceased and surviving patients revealed implications on its ion-channel activities and correlation with patient mortality.

One major obstacle in designing a successful therapeutic regimen to combat COVID-19 pandemic is the frequent occurrence of mutations in the SARS-CoV-2 resulting in patient to patient variations. Out of the four structural proteins of SARS-CoV-2 namely, spike, envelope, nucleocapsid and membrane, envelope protein governs the virus pathogenicity and induction of acute-respiratory-distress-syndrome which is the major cause of death in COVID-19 patients. These effects are facilitated by the viroporin (ion-channel) like activities of the envelope protein. Our current work reports metagenomic analysis of envelope protein at the amino acid sequence level through mining all the available SARS-CoV-2 genomes from the GISAID and coronapp servers. We found majority of mutations in envelope protein were localized at or near PDZ binding motif. Our analysis also demonstrates that the acquired mutations might have important implications on its structure and ion-channel activity. A statistical correlation between specific mutations (e.g. F4F, R69I, P71L, L73F) with patient mortalities were also observed, based on the patient data available for 18,691 SARS-CoV-2-genomes in the GISAID database till 30 April 2021. Albeit, whether these mutations exist as the cause or the effect of co-infections and/or co-morbid disorders within COVID-19 patients is still unclear. Moreover, most of the current vaccine and therapeutic interventions are revolving around spike protein. However, emphasizing on envelope protein's (1) conserved epitopes, (2) pathogenicity attenuating mutations, and (3) mutations present in the deceased patients, as reported in our present study, new directions to the ongoing efforts of therapeutic developments against COVID-19 can be achieved by targeting envelope viroporin.

Suramin, penciclovir, and anidulafungin exhibit potential in the treatment of COVID-19 via binding to nsp12 of SARS-CoV-2.

COVID-19, for which no confirmed therapeutic agents are available, has claimed over 48,14,000 lives globally. A feasible and quicker method to resolve this problem may be 'drug repositioning'. We investigated selected FDA and WHO-EML approved drugs based on their previously promising potential as antivirals, antibacterials or antifungals. These drugs were docked onto the nsp12 protein, which reigns the RNA-dependent RNA polymerase activity of SARS-CoV-2, a key therapeutic target for coronaviruses. Docked complexes were reevaluated using MM-GBSA analysis and the top three inhibitor-protein complexes were subjected to 100 ns long molecular dynamics simulation followed by another round of MM-GBSA analysis. The RMSF plots, binding energies and the mode of physicochemical interaction of the active site of the protein with the drugs were evaluated. Suramin, Penciclovir, and Anidulafungin were found to bind to nsp12 with similar binding energies as that of Remdesivir, which has been used as a therapy for COVID-19. In addition, recent experimental evidences indicate that these drugs exhibit antiviral efficacy against SARS-CoV-2. Such evidence, along with the significant and varied physical interactions of these drugs with the key viral enzyme outlined in this investigation, indicates that they might have a prospective therapeutic potential in the treatment of COVID-19 as monotherapy or combination therapy with Remdesivir.

Revealing the Structural Plasticity of SARS-CoV-2 nsp7 and nsp8 Using Structural Proteomics.

Coronavirus (CoV) nonstructural proteins (nsps) assemble to form the replication-transcription complex (RTC) responsible for viral RNA synthesis. nsp7 and nsp8 are important cofactors of the RTC, as they interact and regulate the activity of RNA-dependent RNA polymerase and other nsps. To date, no structure of the full-length SARS-CoV-2 nsp7:nsp8 complex has been published. The current understanding of this complex is based on structures from truncated constructs, with missing electron densities, or from related CoV species where SARS-CoV-2 nsp7 and nsp8 share upward of 90% sequence identity. Despite available structures solved using crystallography and cryo-EM representing detailed static snapshots of the nsp7:nsp8 complex, it is evident that the complex has a high degree of structural plasticity. However, relatively little is known about the conformational dynamics of the individual proteins and how they complex to interact with other nsps. Here, the solution-based structural proteomic techniques, hydrogen-deuterium exchange mass spectrometry (HDX-MS) and cross-linking mass spectrometry (XL-MS), illuminate the dynamics of SARS-CoV-2 full-length nsp7 and nsp8 proteins and the nsp7:nsp8 protein complex. Results presented from the two techniques are complementary and validate the interaction surfaces identified from the published three-dimensional heterotetrameric crystal structure of the SARS-CoV-2 truncated nsp7:nsp8 complex. Furthermore, mapping of XL-MS data onto higher-order complexes suggests that SARS-CoV-2 nsp7 and nsp8 do not assemble into a hexadecameric structure as implied by the SARS-CoV full-length nsp7:nsp8 crystal structure. Instead, our results suggest that the nsp7:nsp8 heterotetramer can dissociate into a stable dimeric unit that might bind to nsp12 in the RTC without significantly altering nsp7-nsp8 interactions.

A systematic review on the efficacies and therapeutic interventions of homoeopathic medicines in combating viral disorders with implications in the currently undergoinghomoeopathic treatment efforts for SARS-CoV-2 infection (COVID-19)

The prevalence of Severe Acute Respiratory Syndrome-Corona Virus-2 (SARS-CoV-2) has undergone a historic transition from December 2019 to June 2020. Under the current circumstances, SARS-CoV-2 has become a key problem for the public health and economic steadiness of the global fraternity. Based on ample evidences from the global epidemiology of SARS-CoV-2 and MERS-CoV (Middle EastRespiratory Syndrome-Corona virus) scientists and physicians strappingly consider these viruses share structural and functional similarities of selected biologically active enzymes namely, 3CLpro, PLproand RdRp. Ultra-diluted homoeopathic medicine has the legacy to combat infectious as well as viral diseases since last two centuries. Thus, a systematic review on existing antiviral homoeopathic therapies was done in the current study and the need of appropriate clinical validation with proper in vitroas well as in vivostudies prior to make clinical endorsements in treating COVID-19 patients with homoeopathic medicines has been explained. A brief summary of the currently undergoing or recently completed homoeopathic treatments of COVID-19 has also been provided to attract many more similar homoeopathic treatment attempts to combat COVID-19.(AU)

Current Insights into the Novel Coronavirus Disease 2019 (COVID-19) and Its Homoeopathic Management

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new coronavirus strain that has not been ever found in humans before December 2019. Both the coronavirus disease 2019 (COVID-19) case fatality rate and deaths per million population in the top 10 affected countries are increasing a lot due to ever-increasing number of new cases among countries facilitated by increased affinity of SARS-CoV-2 to bind human angiotensin-converting enzyme 2 (ACE2) receptors. While human-to-human transmission of SARS-CoV-2 happens through close contact with an infected individual who spreads respiratory droplets through air or other means, its diagnosis relies mainly on detection of nucleic acid. Repurposing drugs such as dexamethasone, remdesivir, favipiravir and TMPRSS2 (trans membrane protease, serine 2) protease inhibitors have been shown to be effective for the treatment of COVID-19 with albeit requirement of further studies to conclude their complete effectiveness. Personal protective measures should be followed to prevent SARS-CoV-2 infection. Additionally, hundreds of clinical trials of vaccines against SARS-CoV-2 are undergoing, while plasma therapy from the COVID-19 survivors is also being tried to treat the severely affected patients. In addition to these aforementioned modern medicines and therapeutic approaches, homoeopathy also holds promising anti-viral effect as evident from its success against flu and other epidemics, historically. Therefore, present article provides a glimpse of advancements made in the area of homoeopathic ways of treating COVID-19 by summarising the recent homoeopathic clinical, research trials and future scopes of homoeopathy to combat the pandemic. After critical review of most of the ongoing or recently completed homoeopathic treatment efforts against SARS-CoV-2, it was identified that Bryonia alba , Arsenicum album and Gelsemium sempervirens are working best among homoeopathic medicines till now. These studies are also suggesting an increased application of these remedies to treat the current pandemic worldwide;therefore, more such studies are warranted. Those further research will pave the way to understand the mechanism of each of these homoeopathic drugs to cure COVID-19 facilitated by optimising their doses, effects and find the best among these multiple options in homoeopathic medicines for plausible mono- or combination therapies.