Repositioning Ivermectin for Covid-19 treatment: Molecular mechanisms of action against SARS-CoV-2 replication

Viral diseases and the environment relationship

Viral diseases have been present throughout human history, with early examples including influenza (1500 B.C.), smallpox (1000 B.C.), and measles (200 B.C.). The term "virus" was first used in the late 1800s to describe microorganisms smaller than bacteria, and significant milestones include the discovery of the polio virus and the development of its vaccine in the mid-1900s, and the identification of HIV/AIDS in the latter part of the 20th century. The 21st century has seen the emergence of new viral diseases such as West Nile Virus, Zika, SARS, MERS, and COVID-19. Human activities, including crowding, travel, poor sanitation, and environmental changes like deforestation and climate change, significantly influence the spread of these diseases. Conversely, viral diseases can impact the environment by polluting water resources, contributing to deforestation, and reducing biodiversity. These environmental impacts are exacerbated by disruptions in global supply chains and increased demands for resources. This review highlights the intricate relationship between viral diseases and environmental factors, emphasizing how human activities and viral disease progression influence each other. The findings underscore the need for integrated approaches to address the environmental determinants of viral diseases and mitigate their impacts on both health and ecosystems.

Design, Synthesis and Biological Exploration of Novel N-(9-Ethyl-9H-Carbazol-3-yl)Acetamide-Linked Benzofuran-1,2,4-Triazoles as Anti-SARS-CoV-2 Agents: Combined Wet/Dry Approach Targeting Main Protease (Mpro), Spike Glycoprotein and RdRp

A novel series of substituted benzofuran-tethered triazolylcarbazoles was synthesized in good to high yields (65-89%) via S-alkylation of benzofuran-based triazoles with 2-bromo-N-(9-ethyl-9H-carbazol-3-yl)acetamide. The inhibitory potency of the synthesized compounds against SARS-CoV-2 was evaluated by enacting molecular docking against its three pivotal proteins, namely, Mpro (main protease; PDB ID: 6LU7), the spike glycoprotein (PDB ID: 6WPT), and RdRp (RNA-dependent RNA polymerase; PDB ID: 6M71). The docking results indicated strong binding affinities between SARS-CoV-2 proteins and the synthesized compounds, which were thereby expected to obstruct the function of SARS proteins. Among the synthesized derivatives, the compounds 9e, 9h, 9i, and 9j exposited the best binding scores of -8.77, -8.76, -8.87, and -8.85 Kcal/mol against Mpro, respectively, -6.69, -6.54, -6.44, and -6.56 Kcal/mol against the spike glycoprotein, respectively, and -7.61, -8.10, -8.01, and -7.54 Kcal/mol against RdRp, respectively. Furthermore, the binding scores of 9b (-8.83 Kcal/mol) and 9c (-8.92 Kcal/mol) against 6LU7 are worth mentioning. Regarding the spike glycoprotein, 9b, 9d, and 9f expressed high binding energies of -6.43, -6.38, and -6.41 Kcal/mol, accordingly. Correspondingly, the binding affinity of 9g (-7.62 Kcal/mol) against RdRp is also noteworthy. Furthermore, the potent compounds were also subjected to ADMET analysis to evaluate their pharmacokinetic properties, suggesting that the compounds 9e, 9h, 9i, and 9j exhibited comparable values. These potent compounds may be selected as inhibitory agents and provide a pertinent context for further investigations.

OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN PRESUMED VETERINARY ANTHELMINTIC DRUG-INDUCED RETINAL TOXICITY: A Glimpse into Underlying Mechanism

PURPOSE

To report optical coherence tomography findings of presumed veterinary anthelmintic drugs (VADs)-induced retinal toxicity that may aid in understanding potential pathogenic mechanisms.

METHODS

This is a retrospective observational case series analysis of patients with vision abnormalities following the accidental or intentional consumption of veterinary anthelmintic drugs. All cases underwent a thorough ophthalmological examination. Moreover, medical records, as well as the initial and follow-up optical coherence tomography images, were thoroughly scrutinized.

RESULTS

Four patients were identified (3 men; mean [range] age, 36.5 [22-52] years). Each patient overdosed on one or two of the following VADs: closantel, triclabendazole, praziquantel, pyrantel pamoate, and niclofolan. The most characteristic optical coherence tomography finding was diffuse, granular, hyperreflective lesions throughout the outer retina, which were initially identified in the ellipsoid zone in two cases. At follow-up, optical coherence tomography exhibited regression of hyperreflective lesions and extensive loss of the outer retinal elements in two patients. In addition, the subfoveal outer retinal layers may be partially preserved.

CONCLUSION

Some veterinary anthelmintic drugs could be detrimental to the human retina if overdosed, resulting in visual disturbances. Optical coherence tomography revealed the mitochondria-enriched ellipsoid zone where outer retinal damage first appeared on, implying that these medications may harm the retina by inhibiting mitochondrial energy metabolism, as they do to eliminate parasites.

14-3-3 Family of Proteins: Biological Implications, Molecular Interactions, and Potential Intervention in Cancer, Virus and Neurodegeneration Disorders

The 14-3-3 family of proteins are highly conserved acidic eukaryotic proteins (25-32 kDa) abundantly present in the body. Through numerous binding partners, the 14-3-3 is responsible for many essential cellular pathways, such as cell cycle regulation and gene transcription control. Hence, its dysregulation has been linked to the onset of critical illnesses such as cancers, neurodegenerative diseases and viral infections. Interestingly, explorative studies have revealed an inverse correlation of 14-3-3 protein in cancer and neurodegenerative diseases, and the direct manipulation of 14-3-3 by virus to enhance infection capacity has dramatically extended its significance. Of these, COVID-19 has been linked to the 14-3-3 proteins by the interference of the SARS-CoV-2 nucleocapsid (N) protein during virion assembly. Given its predisposition towards multiple essential host signalling pathways, it is vital to understand the holistic interactions between the 14-3-3 protein to unravel its potential therapeutic unit in the future. As such, the general structure and properties of the 14-3-3 family of proteins, as well as their known biological functions and implications in cancer, neurodegeneration, and viruses, were covered in this review. Furthermore, the potential therapeutic target of 14-3-3 proteins in the associated diseases was discussed.

Ivermectin ameliorates acute myocarditis via the inhibition of importin-mediated nuclear translocation of NF-κB/p65

BACKGROUND

Myocarditis is an important clinical issue which lacks specific treatment by now. Ivermectin (IVM) is an inhibitor of importin α/β-mediated nuclear translocation. This study aimed to explore the therapeutic effects of IVM on acute myocarditis.

METHODS

Mouse models of coxsackie B3 virus (CVB3) infection-induced myocarditis and experimental autoimmune myocarditis (EAM) were established to evaluate the effects of IVM. Cardiac functions were evaluated by echocardiography and Millar catheter. Cardiac inflammatory infiltration was assessed by histological staining. Cytometric bead array and quantitative real-time PCR were used to detect the levels of pro-inflammatory cytokines. The macrophages and their M1/M2 polarization were analyzed via flow cytometry. Protein expression and binding were detected by co-immunoprecipitation, Western blotting and histological staining. The underlying mechanism was verified in vitro using CVB3-infected RAW264.7 macrophages. Cyclic polypeptide (cTN50) was synthesized to selectively inhibit the nuclear translocation of NF-κB/p65, and CVB3-infected RAW264.7 cells were treated with cTN50.

RESULTS

Increased expression of importin β was observed in both models. IVM treatment improved cardiac functions and reduced the cardiac inflammation associated with CVB3-myocarditis and EAM. Furthermore, the pro-inflammatory cytokine (IL-1β/IL-6/TNF-α) levels were downregulated via the inhibition of the nuclear translocation of NF-κB/p65 in macrophages. IVM and cTN50 treatment also inhibited the nuclear translocation of NF-κB/p65 and downregulated the expression of pro-inflammatory cytokines in RAW264.7 macrophages.

CONCLUSIONS

Ivermectin inhibits the nuclear translocation of NF-κB/p65 and the expression of major pro-inflammatory cytokines in myocarditis. The therapeutic effects of IVM on viral and non-viral myocarditis models suggest its potential application in the treatment of acute myocarditis.

Why Certain Repurposed Drugs Are Unlikely to Be Effective Antivirals to Treat SARS-CoV-2 Infections

Most repurposed drugs have proved ineffective for treating COVID-19. We evaluated median effective and toxic concentrations (EC50, CC50) of 49 drugs, mostly from previous clinical trials, in Vero cells. Ratios of reported unbound peak plasma concentrations, (Cmax)/EC50, were used to predict the potential in vivo efficacy. The 20 drugs with the highest ratios were retested in human Calu-3 and Caco-2 cells, and their CC50 was determined in an expanded panel of cell lines. Many of the 20 drugs with the highest ratios were inactive in human Calu-3 and Caco-2 cells. Antivirals effective in controlled clinical trials had unbound Cmax/EC50 ≥ 6.8 in Calu-3 or Caco-2 cells. EC50 of nucleoside analogs were cell dependent. This approach and earlier availability of more relevant cultures could have reduced the number of unwarranted clinical trials.

Ivermectin for treatment of COVID-19: A systematic review and meta-analysis

The effect of ivermectin (IVM) in treating coronavirus disease 2019 (COVID-19) is still controversial, yet the drug has been widely used in the world. The aim of this review was to systematically evaluate the clinical outcomes of IVM in patients with COVID-19. From inception to June 22, 2023, the PubMed, EMBASE, Web of Science (WOS), and scopus databases were searched for relevant observational studies on the risk of RA in migraineurs. We searched PubMed/Medline, EMBASE, the Cochrane Library, Web of Science, medRxiv, and bioRxiv to collect all relevant publications from inception to June 22, 2023. Primary outcomes were all-cause mortality rate, mechanical ventilation (MV) requirement, PCR negative conversion, and adverse events (AEs). Revman 5.4 was used to assess the risk of bias (RoB) and quality of evidence. Thirty-three RCTs (n = 10,489) were included. No significant difference in all-cause mortality rates or PCR negative conversion between IVM and controls. There were significant differences in MV requirement (RR 0.67, 95% CI 0.47-0.96) and AEs (RR 0.87, 95% CI 0.80-0.95) between the two groups. Ivermectin could reduce the risk of MV requirement and AEs in patients with COVID-19, without increasing other risks. In the absence of a better alternative, clinicians could use it with caution.

A deep learning framework for predicting molecular property based on multi-type features fusion

Extracting expressive molecular features is essential for molecular property prediction. Sequence-based representation is a common representation of molecules, which ignores the structure information of molecules. While molecular graph representation has a weak ability in expressing the 3D structure. In this article, we try to make use of the advantages of different type representations simultaneously for molecular property prediction. Thus, we propose a fusion model named DLF-MFF, which integrates the multi-type molecular features. Specifically, we first extract four different types of features from molecular fingerprints, 2D molecular graph, 3D molecular graph and molecular image. Then, in order to learn molecular features individually, we use four essential deep learning frameworks, which correspond to four distinct molecular representations. The final molecular representation is created by integrating the four feature vectors and feeding them into prediction layer to predict molecular property. We compare DLF-MFF with 7 state-of-the-art methods on 6 benchmark datasets consisting of multiple molecular properties, the experimental results show that DLF-MFF achieves state-of-the-art performance on 6 benchmark datasets. Moreover, DLF-MFF is applied to identify potential anti-SARS-CoV-2 inhibitor from 2500 drugs. We predict probability of each drug being inferred as a 3CL protease inhibitor and also calculate the binding affinity scores between each drug and 3CL protease. The results show that DLF-MFF product better performance in the identification of anti-SARS-CoV-2 inhibitor. This work is expected to offer novel research perspectives for accurate prediction of molecular properties and provide valuable insights into drug repurposing for COVID-19.

Therapeutic Management with Repurposing Approaches: A Mystery During COVID-19 Outbreak

The ubiquitous pandemic that emerged due to COVID-19 affected the whole planet. People all over the globe became vulnerable to the unpredictable emergence of coronavirus. The sudden emergence of respiratory disease in coronavirus infected several patients. This affected human life drastically, from mild symptoms to severe illness, leading to mortality. COVID-19 is an exceptionally communicable disease caused by SARS-CoV-2. According to a genomic study, the viral spike RBD interactions with the host ACE2 protein from several coronavirus strains and the interaction between RBD and ACE2 highlighted the potential change in affinity from the virus causing the COVID-19 outbreak to a progenitor type of SARS-CoV-2. SARS-CoV-2, which could be the principal reservoir, is phylogenetically related to the SARS-like bat virus. Other research works reported that intermediary hosts for the transmission of viruses to humans could include cats, bats, snakes, pigs, ferrets, orangutans, and monkeys. Even with the arrival of vaccines and individuals getting vaccinated and treated with FDAapproved repurposed drugs like Remdesivir, the first and foremost steps aimed towards the possible control and minimization of community transmission of the virus include social distancing, self-realization, and self-health care. In this review paper, we discussed and summarized various approaches and methodologies adopted and proposed by researchers all over the globe to help with the management of this zoonotic outbreak by following repurposed approaches.

Promising clinical outcomes of nano-curcumin treatment as an adjunct therapy in hospitalized COVID-19 patients: A randomized, double-blinded, placebo-controlled trial

Different immunomodulation strategies have been used to manage COVID-19 due to the complex immune-inflammatory processes involved in the pathogenesis of this infection. Curcumin with its powerful anti-inflammatory and antiviral properties could serve as a possible COVID-19 therapy. In this study, a randomized, double-blinded, placebo-controlled trial was performed to investigate the effectiveness and safety of nano-curcumin oral soft gels as a complementary therapy in moderate-severe COVID-19 patients. Hydroxychloroquine (HCQ) plus sofosbuvir was routinely administered to all 42 COVID-19 patients, who were randomly assigned to receive 140 mg of nano-curcumin or placebo for 14 days. CT scans of the chest were taken, and blood tests were run for all patients at time points of 0, 7, and 14 days. Our results indicated that C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels significantly decreased from baseline in the nano-curcumin-treated group on day 7. Furthermore, blood levels of D-dimer, CRP, serum ferritin, ESR, and inflammatory cytokines including IL-6, IL-8, and IL-10 decreased more significantly in the nano-curcumin-treated group after 14 days. Additionally, the nano-curcumin group showed significant improvements in chest CT scores, oxygen saturation levels, and hospitalization duration. Based on our data, oral administration of nano-curcumin may be regarded as a promising adjunct treatment for COVID-19 patients due to its ability to speed up chest clearance and recovery.

Drug repositioning in the COVID-19 pandemic: fundamentals, synthetic routes, and overview of clinical studies

INTRODUCTION

Drug repositioning is a strategy to identify a new therapeutic indication for molecules that have been approved for other conditions, aiming to speed up the traditional drug development process and reduce its costs. The high prevalence and incidence of coronavirus disease 2019 (COVID-19) underline the importance of searching for a safe and effective treatment for the disease, and drug repositioning is the most rational strategy to achieve this goal in a short period of time. Another advantage of repositioning is the fact that these compounds already have established synthetic routes, which facilitates their production at the industrial level. However, the hope for treatment cannot allow the indiscriminate use of medicines without a scientific basis.

RESULTS

The main small molecules in clinical trials being studied to be potentially repositioned to treat COVID-19 are chloroquine, hydroxychloroquine, ivermectin, favipiravir, colchicine, remdesivir, dexamethasone, nitazoxanide, azithromycin, camostat, methylprednisolone, and baricitinib. In the context of clinical tests, in general, they were carried out under the supervision of large consortiums with a methodology based on and recognized in the scientific community, factors that ensure the reliability of the data collected. From the synthetic perspective, compounds with less structural complexity have more simplified synthetic routes. Stereochemical complexity still represents the major challenge in the preparation of dexamethasone, ivermectin, and azithromycin, for instance.

CONCLUSION

Remdesivir and baricitinib were approved for the treatment of hospitalized patients with severe COVID-19. Dexamethasone and methylprednisolone should be used with caution. Hydroxychloroquine, chloroquine, ivermectin, and azithromycin are ineffective for the treatment of the disease, and the other compounds presented uncertain results. Preclinical and clinical studies should not be analyzed alone, and their methodology's accuracy should also be considered. Regulatory agencies are responsible for analyzing the efficacy and safety of a treatment and must be respected as the competent authorities for this decision, avoiding the indiscriminate use of medicines.

De Novo Design of Anti-COVID Drugs Using Machine Learning-Based Equivariant Diffusion Model Targeting the Spike Protein

The drug discovery and research for an anti-COVID-19 drug has been ongoing despite repurposed drugs in the market. Over time, these drugs were discontinued due to side effects. The search for effective drugs is still under process. The role of Machine Learning (ML) is critical in the search for novel drug compounds. In the current work, using the equivariant diffusion model, we built novel compounds targeting the spike protein of SARS-CoV-2. Using the ML models, 196 de novo compounds were generated which had no hits on any major chemical databases. These novel compounds fulfilled all the criteria of ADMET properties to be lead-like and drug-like compounds. Of the 196 compounds, 15 were docked with high confidence in the target. These compounds were further subjected to molecular docking, the best compound having an IUPAC name of (4aS,4bR,8aS,8bS)-4a,8a-dimethylbiphenylene-1,4,5,8(4aH,4bH,8aH,8bH)-tetraone and a binding score of -6.930 kcal/mol. The principal compound is labeled as CoECG-M1. Density Function Theory (DFT) and Quantum optimization was carried out along with the study of ADMET properties. This suggests that the compound has potential drug-like properties. The docked complex was further subjected to MD simulations, GBSA, and metadynamics simulations to gain insights into the stability of binding. The model can be in the future modified to improve the positive docking rate.

Evolution of SARS-CoV-2 Variants: Implications on Immune Escape, Vaccination, Therapeutic and Diagnostic Strategies

The COVID-19 pandemic caused by SARS-CoV-2 is associated with a lower fatality rate than its SARS and MERS counterparts. However, the rapid evolution of SARS-CoV-2 has given rise to multiple variants with varying pathogenicity and transmissibility, such as the Delta and Omicron variants. Individuals with advanced age or underlying comorbidities, including hypertension, diabetes and cardiovascular diseases, are at a higher risk of increased disease severity. Hence, this has resulted in an urgent need for the development of better therapeutic and preventive approaches. This review describes the origin and evolution of human coronaviruses, particularly SARS-CoV-2 and its variants as well as sub-variants. Risk factors that contribute to disease severity and the implications of co-infections are also considered. In addition, various antiviral strategies against COVID-19, including novel and repurposed antiviral drugs targeting viral and host proteins, as well as immunotherapeutic strategies, are discussed. We critically evaluate strategies of current and emerging vaccines against SARS-CoV-2 and their efficacy, including immune evasion by new variants and sub-variants. The impact of SARS-CoV-2 evolution on COVID-19 diagnostic testing is also examined. Collectively, global research and public health authorities, along with all sectors of society, need to better prepare against upcoming variants and future coronavirus outbreaks.

A perspective study of the possible impact of obeticholic acid against SARS-CoV-2 infection

The causative agent of CoV disease 2019 is a new coronavirus CoV type 2, affecting the respiratory tract with severe manifestations (SARS-CoV-2). Covid-19 is mainly symptomless, with slight indications in about 85% of the affected cases. Many efforts were done to face this pandemic by testing different drugs and agents to make treatment protocols in different countries. However, the use of these proposed drugs is associated with the development of adverse events. Remarkably, the successive development of SARS-CoV-2 variants which could affect persons even they were vaccinated, prerequisite wide search to find efficient and safe agents to face SARS-CoV-2 infection. Obeticholic acid (OCA), which has anti-inflammatory effects, may efficiently treat Covid-19. Thus, the goal of this perspective study is to focus on the possible medicinal effectiveness in managing Covid-19. OCA is a powerful farnesoid X receptor (FXR) agonist possessing marked antiviral and anti-inflammatory effects. FXR is dysregulated in Covid-19 resulting in hyper-inflammation with concurrent occurrence of hypercytokinemia. Interestingly, OCA inhibits the reaction between this virus and angiotensin-converting enzyme type 2 (ACE2) receptors. FXR agonists control the expression of ACE2 and the inflammatory signaling pathways in this respiratory syndrome, which weakens the effects of Covid-19 disease and accompanied complications. Taken together, FXR agonists like OCA may reveal both direct and indirect impacts in the modulation of immune reaction in SARS-CoV-2 conditions. It is highly recommended to perform many investigations regarding different phases of the discovery of new drugs.

COVID-19 drugs: potential interaction with ATP-binding cassette transporters P-glycoprotein and breast cancer resistance protein

Background

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2, has resulted in acute respiratory distress, fatal systemic manifestations (extrapulmonary as well as pulmonary), and premature mortality among many patients. Therapy for COVID-19 has focused on the treatment of symptoms and of acute inflammation (cytokine storm) and the prevention of viral infection. Although the mechanism of COVID-19 is not fully understood, potential clinical targets have been identified for pharmacological, immunological, and vaccinal approaches.

Area covered

Pharmacological approaches including drug repositioning have been a priority for initial COVID-19 therapy due to the time-consuming nature of the vaccine development process. COVID-19 drugs have been shown to manage the antiviral infection cycle (cell entry and replication of proteins and genomic RNA) and anti-inflammation. In this review, we evaluated the interaction of current COVID-19 drugs with two ATP-binding cassette transporters [P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP)] and potential drug-drug interactions (DDIs) among COVID-19 drugs, especially those associated with P-gp and BCRP efflux transporters.

Expert opinion

Overall, understanding the pharmacodynamic/pharmacokinetic DDIs of COVID-19 drugs can be useful for pharmacological therapy in COVID-19 patients.

In Vitro Screening and MD Simulations of Thiourea Derivatives against SARS-CoV-2 in Association with Multidrug Resistance ABCB1 Transporter

Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) is considered a global public health concern since it causes high morbidity and mortality. Recently, it has been reported that repurposed anti-COVID-19 drugs might interact with multidrug resistance ABC transporter, particularly ABCB1. In the current study, a series of thiourea derivatives were screened as potential inhibitors against SARS-CoV-2 by targeting the attachment of receptor binding domain (RBD) of spike protein with ACE2 and their interaction with human ABCB1 has also been explored. The results indicated strong impairment of RBD-ACE2 attachment by BB IV-46 with a percentage inhibition of 95.73 ± 1.79% relative to the positive control, while BB V-19 was proven inactive with a percentage inhibition of 50.90 ± 0.84%. The same compound (BB IV-46) interacted with ABCB1 and potentially inhibited cell proliferation of P-gp overexpressing cell line with an IC₅₀ value of 4.651 ± 0.06 μM. BB V-19, which was inactive against SARS-CoV-2, was inactive against ABCB1 with a higher IC₅₀ value of 35.72 ± 0.09 μM. Furthermore, molecular dynamics simulations followed by binding free-energy analysis explored the binding interaction of BB IV-46 and BB V-19 to RBD region of spike protein of SARS-CoV-2. The results confirmed that compound BB IV-46 interacted strongly with RBD with a significant binding energy (-127.0 kJ/mol), while BB V-19 interacted weakly (-29.30 kJ/mol). The key interacting residues of the RBD involved in binding included Leu441, Lys444, and Tyr449. This study highlights the importance of BB IV-46 against SARS-CoV-2; however, further pharmacokinetic and pharmacodynamics studies are needed to be done.

Current Treatments for COVID-19: Application of Supercritical Fluids in the Manufacturing of Oral and Pulmonary Formulations

Even though more than two years have passed since the emergence of COVID-19, the research for novel or repositioned medicines from a natural source or chemically synthesized is still an unmet clinical need. In this review, the application of supercritical fluids to the development of novel or repurposed medicines for COVID-19 and their secondary bacterial complications will be discussed. We envision three main applications of the supercritical fluids in this field: (i) drug micronization, (ii) supercritical fluid extraction of bioactives and (iii) sterilization. The supercritical fluids micronization techniques can help to improve the aqueous solubility and oral bioavailability of drugs, and consequently, the need for lower doses to elicit the same pharmacological effects can result in the reduction in the dose administered and adverse effects. In addition, micronization between 1 and 5 µm can aid in the manufacturing of pulmonary formulations to target the drug directly to the lung. Supercritical fluids also have enormous potential in the extraction of natural bioactive compounds, which have shown remarkable efficacy against COVID-19. Finally, the successful application of supercritical fluids in the inactivation of viruses opens up an opportunity for their application in drug sterilization and in the healthcare field.

A review on computer-aided chemogenomics and drug repositioning for rational COVID-19 drug discovery

Application of materials capable of energy harvesting to increase the efficiency and environmental adaptability is sometimes reflected in the ability of discovery of some traces in an environment-either experimentally or computationally-to enlarge practical application window. The emergence of computational methods, particularly computer-aided drug discovery (CADD), provides ample opportunities for the rapid discovery and development of unprecedented drugs. The expensive and time-consuming process of traditional drug discovery is no longer feasible, for nowadays the identification of potential drug candidates is much easier for therapeutic targets through elaborate in silico approaches, allowing the prediction of the toxicity of drugs, such as drug repositioning (DR) and chemical genomics (chemogenomics). Coronaviruses (CoVs) are cross-species viruses that are able to spread expeditiously from the into new host species, which in turn cause epidemic diseases. In this sense, this review furnishes an outline of computational strategies and their applications in drug discovery. A special focus is placed on chemogenomics and DR as unique and emerging system-based disciplines on CoV drug and target discovery to model protein networks against a library of compounds. Furthermore, to demonstrate the special advantages of CADD methods in rapidly finding a drug for this deadly virus, numerous examples of the recent achievements grounded on molecular docking, chemogenomics, and DR are reported, analyzed, and interpreted in detail. It is believed that the outcome of this review assists developers of energy harvesting materials and systems for detection of future unexpected kinds of CoVs or other variants.

SARS-CoV-2 Non-Structural Proteins and Their Roles in Host Immune Evasion

Coronavirus disease 2019 (COVID-19) has caused an unprecedented global crisis and continues to threaten public health. The etiological agent of this devastating pandemic outbreak is the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). COVID-19 is characterized by delayed immune responses, followed by exaggerated inflammatory responses. It is well-established that the interferon (IFN) and JAK/STAT signaling pathways constitute the first line of defense against viral and bacterial infections. To achieve viral replication, numerous viruses are able to antagonize or hijack these signaling pathways to attain productive infection, including SARS-CoV-2. Multiple studies document the roles of several non-structural proteins (NSPs) of SARS-CoV-2 that facilitate the establishment of viral replication in host cells via immune escape. In this review, we summarize and highlight the functions and characteristics of SARS-CoV-2 NSPs that confer host immune evasion. The molecular mechanisms mediating immune evasion and the related potential therapeutic strategies for controlling the COVID-19 pandemic are also discussed.

Ivermectin: A Controversial Focal Point during the COVID-19 Pandemic

The SARS-CoV-2 pandemic has confirmed the apocalyptic predictions that virologists have been making for several decades. The challenge the world is facing is that of trying to find a possible treatment, and a viable and expedient option for addressing this challenge is the repurposing of drugs. However, in some cases, although these drugs are approved for use in humans, the mechanisms of action involved are unknown. In this sense, to justify its therapeutic application to a new disease, it is ideal, but not necessary, to know the basic mechanisms of action involved in a drug's biological effects. This review compiled the available information regarding the various effects attributed to Ivermectin. The controversy over its use for the treatment of COVID-19 is demonstrated by this report that considers the proposal unfeasible because the therapeutic doses proposed to achieve this effect cannot be achieved. However, due to the urgent need to find a treatment, an exhaustive and impartial review is necessary in order to integrate the knowledge that exists, to date, of the possible mechanisms through which the treatment may be helpful in defining safe doses and schedules of Ivermectin.

Ivermectin: recent approaches in the design of novel veterinary and human medicines

Ivermectin (IVM) is a drug widely used in veterinary and human medicine for the management of parasitic diseases. Its repositioning potential has been recently considered for the treatment of different diseases, such as cancer and viral infections. However, IVM faces some limitations to its formulations due to its low water solubility and bioavailability, along with reports of drug resistance. In this sense, novel technological approaches have been explored to optimize its formulations and/or to develop innovative medicines. Therefore, this review discusses the strategies proposed in the last decade to improve the safety and efficacy of IVM and to explore its novel therapeutic applications. Among these technologies, the use of micro/nano-drug delivery systems is the most used approach, followed by long-acting formulations. In general, the development of these novel formulations seems to run side by side in veterinary and human health, showing a shared interface between the two areas. Although the technologies proposed indicate a promising future in the development of innovative dosage forms containing IVM, its safety and therapeutic targets must be further evaluated. Overall, these approaches comprise tailoring drug delivery profiles, decreasing the risks of developing drug resistance, and supporting the application of IVM for reaching different therapeutic targets.

COVID-19 and the Immune Response: A Multi-Phasic Approach to the Treatment of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a viral agent that causes Coronavirus disease 2019 (COVID-19), a disease that causes flu-like symptoms that, when exacerbated, can have life-threatening consequences. COVID-19 has been linked to persistent symptoms, sequelae, and medical complications that can last months after the initial infection. This systematic review aims to elucidate the innate and adaptive immune mechanisms involved and identify potential characteristics of COVID-19 pathology that may increase symptom duration. We also describe he three different stages of COVID-19—viral replication, immune hyperactivation, and post-acute sequelae—as well as each phase’s corresponding immune response. Finally, we use this multiphasic approach to describe different treatment approaches for each of the three stages—antivirals, immunosuppressants and monoclonal antibodies, and continued immunosuppressants—to fully curate the treatment to the stage of disease.

Potential therapeutic effects of Ivermectin in COVID-19

COVID-19 is a critical pandemic that affected communities around the world, and there is currently no specific drug treatment for it. The virus enters the human cells via spikes and induces cytokine production and finally arrests the cell cycle. Ivermectin shows therapeutic potential for treating COVID-19 infection based on in vitro studies. Docking studies have shown a strong affinity between Ivermectin and some virulence factors of COVID-19. Notably, clinical evidence has demonstrated that Ivermectin with usual doses is effective by both the prophylactic and therapeutic approaches in all phases of the disease. Ivermectin inhibits both the adhesion and replication of the virus. Local therapy of the lung with Ivermectin or combination therapy may get better results and decrease the dose of the drug.

Interaction of the new inhibitor paxlovid (PF-07321332) and ivermectin with the monomer of the main protease SARS-CoV-2: A volumetric study based on molecular dynamics, elastic networks, classical thermodynamics and SPT

The COVID-19 pandemic has accelerated the study of drugs, most notably ivermectin and more recently Paxlovid (PF-07321332) which is in phase III clinical trials with experimental data showing covalent binding to the viral protease Mpro. Theoretical developments of catalytic site-directed docking support thermodynamically feasible non-covalent binding to Mpro. Here we show that Paxlovid binds non-covalently at regions other than the catalytic sites with energies stronger than reported and at the same binding site as the ivermectin B1a homologue, all through theoretical methodologies, including blind docking. We volumetrically characterize the non-covalent interaction of the ivermectin homologues (avermectins B1a and B1b) and Paxlovid with the mMpro monomer, through molecular dynamics and scaled particle theory (SPT). Using the fluctuation-dissipation theorem (FDT), we estimated the electric dipole moment fluctuations at the surface of each of complex involved in this study, with similar trends to that observed in the interaction volume. Using fluctuations of the intrinsic volume and the number of flexible fragments of proteins using anisotropic and Gaussian elastic networks (ANM+GNM) suggests the complexes with ivermectin are more dynamic and flexible than the unbound monomer. In contrast, the binding of Paxlovid to mMpro shows that the mMpro-PF complex is the least structurally dynamic of all the species measured in this investigation. The results support a differential molecular mechanism of the ivermectin and PF homologues in the mMpro monomer. Finally, the results showed that Paxlovid despite beingbound in different sites through covalent or non-covalent forms behaves similarly in terms of its structural flexibility and volumetric behaviour.

Repurposing Molnupiravir for COVID-19: The Mechanisms of Antiviral Activity

Molnupiravir is a β-d-N4-hydroxycytidine-5'-isopropyl ester (NHC) compound that exerts antiviral activity against various RNA viruses such as influenza, SARS, and Ebola viruses. Thus, the repurposing of Molnupiravir has gained significant attention for combatting infection with SARS-CoV-2, the etiological agent of COVID-19. Recently, Molnupiravir was granted authorization for the treatment of mild-to-moderate COVID-19 in adults. Findings from in vitro experiments, in vivo studies and clinical trials reveal that Molnupiravir is effective against SARS-CoV-2 by inducing viral RNA mutagenesis, thereby giving rise to mutated complementary RNA strands that generate non-functional viruses. To date, the data collectively suggest that Molnupiravir possesses promising antiviral activity as well as favorable prophylactic efficacy, attributed to its effective mutagenic property of disrupting viral replication. This review discusses the mechanisms of action of Molnupiravir and highlights its clinical utility by disabling SARS-CoV-2 replication, thereby ameliorating COVID-19 severity. Despite relatively few short-term adverse effects thus far, further detailed clinical studies and long-term pharmacovigilance are needed in view of its mutagenic effects.

Non-Antibiotic Drug Repositioning as an Alternative Antimicrobial Approach

The worldwide scenario of antibiotic resistance and the falling number of funds for the development of novel antibiotics have led research efforts toward the study of specific cost-effective strategies aimed at discovering drugs against microbial infections. Among the potential options, drug repositioning, which has already exhibited satisfactory results in other medical fields, came out as the most promising. It consists of finding new uses for previously approved medicines and, over the years, many “repurposed drugs” displayed some encouraging in vitro and in vivo results beyond their initial application. The principal theoretical justification for reusing already existing drugs is that they have known mechanisms of action and manageable side effects. Reuse of old drugs is now considered an interesting approach to overcome the drawbacks of conventional antibiotics. The purpose of this review is to offer the reader a panoramic view of the updated studies concerning the repositioning process of different classes of non-antibiotic drugs in the antimicrobial field. Several research works reported the ability of some non-steroidal anti-inflammatory drugs (NSAIDs), antidepressants, antipsychotics, and statins to counteract the growth of harmful microorganisms, demonstrating an interesting winning mode to fight infectious diseases caused by antimicrobial resistant bacteria.

Non-effectiveness of Ivermectin on Inpatients and Outpatients With COVID-19; Results of Two Randomized, Double-Blinded, Placebo-Controlled Clinical Trials

Background

Ivermectin which was widely considered as a potential treatment for COVID-19, showed uncertain clinical benefit in many clinical trials. Performing large-scale clinical trials to evaluate the effectiveness of this drug in the midst of the pandemic, while difficult, has been urgently needed.

Methods

We performed two large multicenter randomized, double-blind, placebo-controlled clinical trials evaluating the effectiveness of ivermectin in treating inpatients and outpatients with COVID-19 infection. The intervention group received ivermectin, 0.4mg/kg of body weight per day for 3 days. In the control group, placebo tablets were used for 3 days.

Results

Data for 609 inpatients and 549 outpatients were analyzed. In hospitalized patients, complete recovery was significantly higher in the ivermectin group (37%) compared to placebo group (28%; RR, 1.32 [95% CI, 1.04–1.66]; p-value = 0.02). On the other hand, the length of hospital stay was significantly longer in the ivermectin group with a mean of 7.98 ± 4.4 days compared to the placebo receiving group with a mean of 7.16 ± 3.2 days (RR, 0.80 [95% CI, 0.15–1.45]; p-value = 0.02). In outpatients, the mean duration of fever was significantly shorter (2.02 ± 0.11 days) in the ivermectin group versus (2.41 ± 0.13 days) placebo group with p value = 0.020. On the day seventh of treatment, fever (p-value = 0.040), cough (p-value = 0.019), and weakness (p-value = 0.002) were significantly higher in the placebo group compared to the ivermectin group. Among all outpatients, 7% in ivermectin group and 5% in placebo group needed to be hospitalized (RR, 1.36 [95% CI, 0.65–2.84]; p-value = 0.41). Also, the result of RT-PCR on day five after treatment was negative for 26% of patients in the ivermectin group versus 32% in the placebo group (RR, 0.81 [95% CI, 0.60–1.09]; p-value = 0.16).

Conclusion

Our data showed, ivermectin, compared with placebo, did not have a significant potential effect on clinical improvement, reduced admission in ICU, need for invasive ventilation, and death in hospitalized patients; likewise, no evidence was found to support the prescription of ivermectin on recovery, reduced hospitalization and increased negative RT-PCR assay for SARS-CoV-2 5 days after treatment in outpatients. Our findings do not support the use of ivermectin to treat mild to severe forms of COVID-19.

Clinical Trial Registration

www.irct.ir IRCT20111224008507N5 and IRCT20111224008507N4.

Antiviral Activity of Repurposing Ivermectin against a Panel of 30 Clinical SARS-CoV-2 Strains Belonging to 14 Variants

Over the past two years, several variants of SARS-CoV-2 have emerged and spread all over the world. However, infectivity, clinical severity, re-infection, virulence, transmissibility, vaccine responses and escape, and epidemiological aspects have differed between SARS-CoV-2 variants. Currently, very few treatments are recommended against SARS-CoV-2. Identification of effective drugs among repurposing FDA-approved drugs is a rapid, efficient and low-cost strategy against SARS-CoV-2. One of those drugs is ivermectin. Ivermectin is an antihelminthic agent that previously showed in vitro effects against a SARS-CoV-2 isolate (Australia/VI01/2020 isolate) with an IC50 of around 2 µM. We evaluated the in vitro activity of ivermectin on Vero E6 cells infected with 30 clinically isolated SARS-CoV-2 strains belonging to 14 different variants, and particularly 17 strains belonging to six variants of concern (VOC) (variants related to Wuhan, alpha, beta, gamma, delta and omicron). The in vitro activity of ivermectin was compared to those of chloroquine and remdesivir. Unlike chloroquine (EC50 from 4.3 ± 2.5 to 29.3 ± 5.2 µM) or remdesivir (EC50 from 0.4 ± 0.3 to 25.2 ± 9.4 µM), ivermectin showed a relatively homogeneous in vitro activity against SARS-CoV-2 regardless of the strains or variants (EC50 from 5.1 ± 0.5 to 6.7 ± 0.4 µM), except for one omicron strain (EC50 = 1.3 ± 0.5 µM). Ivermectin (No. EC50 = 219, mean EC50 = 5.7 ± 1.0 µM) was, overall, more potent in vitro than chloroquine (No. EC50 = 214, mean EC50 = 16.1 ± 9.0 µM) (p = 1.3 × 10-34) and remdesivir (No. EC50 = 201, mean EC50 = 11.9 ± 10.0 µM) (p = 1.6 × 10-13). These results should be interpreted with caution regarding the potential use of ivermectin in SARS-CoV-2-infected patients: it is difficult to translate in vitro study results into actual clinical treatment in patients.

COVID-19 at a Glance: An Up-to-Date Overview on Variants, Drug Design and Therapies

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a member of the Coronavirus family which caused the worldwide pandemic of human respiratory illness coronavirus disease 2019 (COVID-19). Presumably emerging at the end of 2019, it poses a severe threat to public health and safety, with a high incidence of transmission, predominately through aerosols and/or direct contact with infected surfaces. In 2020, the search for vaccines began, leading to the obtaining of, to date, about twenty COVID-19 vaccines approved for use in at least one country. However, COVID-19 continues to spread and new genetic mutations and variants have been discovered, requiring pharmacological treatments. The most common therapies for COVID-19 are represented by antiviral and antimalarial agents, antibiotics, immunomodulators, angiotensin II receptor blockers, bradykinin B2 receptor antagonists and corticosteroids. In addition, nutraceuticals, vitamins D and C, omega-3 fatty acids and probiotics are under study. Finally, drug repositioning, which concerns the investigation of existing drugs for new therapeutic target indications, has been widely proposed in the literature for COVID-19 therapies. Considering the importance of this ongoing global public health emergency, this review aims to offer a synthetic up-to-date overview regarding diagnoses, variants and vaccines for COVID-19, with particular attention paid to the adopted treatments.