Drug Repositioning

Atomistic de-novo inhibitor generation guided drug repurposing for SARS-CoV-2 spike protein with free energy validation by well-tempered metadynamics

Wed, 2021-05-05 06:00

Chem Asian J. 2021 May 5. doi: 10.1002/asia.202100268. Online ahead of print.

ABSTRACT

Computational drug design is increasingly becoming important with the new and unforeseen diseases like COVID-19. In this study, we present a new computational de novo drug design and repurposing method and applied it to find plausible drug candidates for the receptor binding domain (RBD) of SARS-CoV-2 (COVID-19). Our study comprises three steps: atom-by-atom generation of new molecules around a receptor, structural similarity mapping to existing approved and investigational drugs, and validation of their binding strengths to the viral spike proteins based on rigorous all-atom, explicit-water well-tempered metadynamics free energy calculations. By choosing the receptor binding domain of the viral spike protein, we showed that some of our new molecules and some of the repurposable drugs have stronger binding to RBD than hACE2. To validate our approach, we also calculated the free energy of hACE2 and RBD, and found it to be in an excellent agreement with experiments. These pool of drugs will allow strategic repurposing against COVID-19 for a particular prevailing conditions.

PMID:33949124 | DOI:10.1002/asia.202100268

Categories: Literature Watch

Direct acting anti-hepatitis C combinations as potential COVID-19 protease inhibitors

Wed, 2021-05-05 06:00

Virusdisease. 2021 Apr 29:1-7. doi: 10.1007/s13337-021-00691-6. Online ahead of print.

ABSTRACT

The coronavirus pandemic could be the most threatening outbreak in the twenty-first century. According to the latest records of world health organization, more than 130 millions have been infected by COVID-19, with more than 2.9 million reported deaths. Yet, there is no magic cure for treatment of COVID-19. The concept of drug repurposing has been introduced as a fast, life-saving approach for drug discovery. Drug repurposing infers investigating already approved drugs for new indications, using the available information about pathophysiology of diseases and pharmacodynamics of drugs. In a recent work, more than 3000 FDA approved drugs were tested using virtual screening as potential antiviral agents for COVID-19. In this work, the top ranked five hits from the previous docking results together with drugs of similar chemical feature and/or mechanistic destinations were further tested using AutoDock Vina. The results showed that anti-HCV combinations could be potential therapeutic regimens for COVID-19 infections.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13337-021-00691-6.

PMID:33948452 | PMC:PMC8083918 | DOI:10.1007/s13337-021-00691-6

Categories: Literature Watch

GPCR_LigandClassify.py; a rigorous machine learning classifier for GPCR targeting compounds

Wed, 2021-05-05 06:00

Sci Rep. 2021 May 4;11(1):9510. doi: 10.1038/s41598-021-88939-5.

ABSTRACT

The current study describes the construction of various ligand-based machine learning models to be used for drug-repurposing against the family of G-Protein Coupled Receptors (GPCRs). In building these models, we collected > 500,000 data points, encompassing experimentally measured molecular association data of > 160,000 unique ligands against > 250 GPCRs. These data points were retrieved from the GPCR-Ligand Association (GLASS) database. We have used diverse molecular featurization methods to describe the input molecules. Multiple supervised ML algorithms were developed, tested and compared for their accuracy, F scores, as well as for their Matthews' correlation coefficient scores (MCC). Our data suggest that combined with molecular fingerprinting, ensemble decision trees and gradient boosted trees ML algorithms are on the accuracy border of the rather sophisticated deep neural nets (DNNs)-based algorithms. On a test dataset, these models displayed an excellent performance, reaching a ~ 90% classification accuracy. Additionally, we showcase a few examples where our models were able to identify interesting connections between known drugs from the Drug-Bank database and members of the GPCR family of receptors. Our findings are in excellent agreement with previously reported experimental observations in the literature. We hope the models presented in this paper synergize with the currently ongoing interest of applying machine learning modeling in the field of drug repurposing and computational drug discovery in general.

PMID:33947911 | DOI:10.1038/s41598-021-88939-5

Categories: Literature Watch

Exploring new uses for existing drugs: innovative mechanisms to fund independent clinical research

Wed, 2021-05-05 06:00

Trials. 2021 May 4;22(1):322. doi: 10.1186/s13063-021-05273-x.

ABSTRACT

BACKGROUND: Finding new therapeutic uses for existing medicines could lead to safe, affordable and timely new treatment options for patients with high medical needs. However, due to a lack of economic incentives, pharmaceutical developers are rarely interested to invest in research with approved medicines, especially when they are out of basic patent or regulatory protection. Consequently, potential new uses for these medicines are mainly studied in independent clinical trials initiated and led by researchers from academia, research institutes, or collaborative groups. Yet, additional financial support is needed to conduct expensive phase III clinical trials to confirm the results from exploratory research.

METHODS: In this study, scientific and grey literature was searched to identify and evaluate new mechanisms for funding clinical trials with repurposed medicines. Semi-structured interviews were conducted with 16 European stakeholders with expertise in clinical research, funding mechanisms and/or drug repurposing between November 2018 and February 2019 to consider the future perspectives of applying new funding mechanisms.

RESULTS: Traditional grant funding awarded by government and philanthropic organisations or companies is well known and widely implemented in all research fields. In contrast, only little research has focused on the application potential of newer mechanisms to fund independent clinical research, such as social impact bonds, crowdfunding or public-private partnerships. Interviewees stated that there is a substantial need for additional financial support in health research, especially in areas where there is limited commercial interest. However, the implementation of new funding mechanisms is facing several practical and financial challenges, such as a lack of expertise and guidelines, high transaction costs and difficulties to measure health outcomes. Furthermore, interviewees highlighted the need for increased collaboration and centralisation at a European and international level to make clinical research more efficient and reduce the need for additional funding.

CONCLUSIONS: New funding mechanisms to support clinical research may become more important in the future but the unresolved issues identified in the current study warrant further exploration.

PMID:33947441 | DOI:10.1186/s13063-021-05273-x

Categories: Literature Watch

Identification of New Potential Inhibitors of Quorum Sensing through a Specialized Multi-Level Computational Approach

Wed, 2021-05-05 06:00

Molecules. 2021 Apr 29;26(9):2600. doi: 10.3390/molecules26092600.

ABSTRACT

Biofilms are aggregates of microorganisms anchored to a surface and embedded in a self-produced matrix of extracellular polymeric substances and have been associated with 80% of all bacterial infections in humans. Because bacteria in biofilms are less amenable to antibiotic treatment, biofilms have been associated with developing antibiotic resistance, a problem that urges developing new therapeutic options and approaches. Interfering with quorum-sensing (QS), an important process of cell-to-cell communication by bacteria in biofilms is a promising strategy to inhibit biofilm formation and development. Here we describe and apply an in silico computational protocol for identifying novel potential inhibitors of quorum-sensing, using CviR-the quorum-sensing receptor from Chromobacterium violaceum-as a model target. This in silico approach combines protein-ligand docking (with 7 different docking programs/scoring functions), receptor-based virtual screening, molecular dynamic simulations, and free energy calculations. Particular emphasis was dedicated to optimizing the discrimination ability between active/inactive molecules in virtual screening tests using a target-specific training set. Overall, the optimized protocol was used to evaluate 66,461 molecules, including those on the ZINC/FDA-Approved database and to the Mu.Ta.Lig Virtual Chemotheca. Multiple promising compounds were identified, yielding good prospects for future experimental validation and for drug repurposing towards QS inhibition.

PMID:33946907 | DOI:10.3390/molecules26092600

Categories: Literature Watch

Antiviral Properties of the NSAID Drug Naproxen Targeting the Nucleoprotein of SARS-CoV-2 Coronavirus

Wed, 2021-05-05 06:00

Molecules. 2021 Apr 29;26(9):2593. doi: 10.3390/molecules26092593.

ABSTRACT

There is an urgent need for specific antiviral treatments directed against SARS-CoV-2 to prevent the most severe forms of COVID-19. By drug repurposing, affordable therapeutics could be supplied worldwide in the present pandemic context. Targeting the nucleoprotein N of the SARS-CoV-2 coronavirus could be a strategy to impede viral replication and possibly other essential functions associated with viral N. The antiviral properties of naproxen, a non-steroidal anti-inflammatory drug (NSAID) that was previously demonstrated to be active against Influenza A virus, were evaluated against SARS-CoV-2. Intrinsic fluorescence spectroscopy, fluorescence anisotropy, and dynamic light scattering assays demonstrated naproxen binding to the nucleoprotein of SARS-Cov-2 as predicted by molecular modeling. Naproxen impeded recombinant N oligomerization and inhibited viral replication in infected cells. In VeroE6 cells and reconstituted human primary respiratory epithelium models of SARS-CoV-2 infection, naproxen specifically inhibited viral replication and protected the bronchial epithelia against SARS-CoV-2-induced damage. No inhibition of viral replication was observed with paracetamol or the COX-2 inhibitor celecoxib. Thus, among the NSAID tested, only naproxen combined antiviral and anti-inflammatory properties. Naproxen addition to the standard of care could be beneficial in a clinical setting, as tested in an ongoing clinical study.

PMID:33946802 | DOI:10.3390/molecules26092593

Categories: Literature Watch

Drug Repurposing Patent Applications January-March 2021

Tue, 2021-05-04 06:00

Assay Drug Dev Technol. 2021 May 4. doi: 10.1089/adt.2021.051. Online ahead of print.

NO ABSTRACT

PMID:33945331 | DOI:10.1089/adt.2021.051

Categories: Literature Watch

A drug-repositioning screen using splicing-sensitive fluorescent reporters identifies novel modulators of VEGF-A splicing with anti-angiogenic properties

Tue, 2021-05-04 06:00

Oncogenesis. 2021 May 3;10(5):36. doi: 10.1038/s41389-021-00323-0.

ABSTRACT

Alternative splicing of the vascular endothelial growth factor A (VEGF-A) terminal exon generates two protein families with differing functions. Pro-angiogenic VEGF-Axxxa isoforms are produced via selection of the proximal 3' splice site of the terminal exon. Use of an alternative distal splice site generates the anti-angiogenic VEGF-Axxxb proteins. A bichromatic splicing-sensitive reporter was designed to mimic VEGF-A alternative splicing and was used as a molecular tool to further investigate this alternative splicing event. Part of VEGF-A's terminal exon and preceding intron were inserted into a minigene construct followed by the coding sequences for two fluorescent proteins. A different fluorescent protein is expressed depending on which 3' splice site of the exon is used during splicing (dsRED denotes VEGF-Axxxa and EGFP denotes VEGF-Axxxb). The fluorescent output can be used to follow splicing decisions in vitro and in vivo. Following successful reporter validation in different cell lines and altering splicing using known modulators, a screen was performed using the LOPAC library of small molecules. Alterations to reporter splicing were measured using a fluorescent plate reader to detect dsRED and EGFP expression. Compounds of interest were further validated using flow cytometry and assessed for effects on endogenous VEGF-A alternative splicing at the mRNA and protein level. Ex vivo and in vitro angiogenesis assays were used to demonstrate the anti-angiogenic effect of the compounds. Furthermore, anti-angiogenic activity was investigated in a Matrigel in vivo model. To conclude, we have identified a set of compounds that have anti-angiogenic activity through modulation of VEGF-A terminal exon splicing.

PMID:33941763 | DOI:10.1038/s41389-021-00323-0

Categories: Literature Watch

Artificial intelligence-based computational framework for drug-target prioritization and inference of novel repositionable drugs for Alzheimer's disease

Tue, 2021-05-04 06:00

Alzheimers Res Ther. 2021 May 3;13(1):92. doi: 10.1186/s13195-021-00826-3.

ABSTRACT

BACKGROUND: Identifying novel therapeutic targets is crucial for the successful development of drugs. However, the cost to experimentally identify therapeutic targets is huge and only approximately 400 genes are targets for FDA-approved drugs. As a result, it is inevitable to develop powerful computational tools that can identify potential novel therapeutic targets. Fortunately, the human protein-protein interaction network (PIN) could be a useful resource to achieve this objective.

METHODS: In this study, we developed a deep learning-based computational framework that extracts low-dimensional representations of high-dimensional PIN data. Our computational framework uses latent features and state-of-the-art machine learning techniques to infer potential drug target genes.

RESULTS: We applied our computational framework to prioritize novel putative target genes for Alzheimer's disease and successfully identified key genes that may serve as novel therapeutic targets (e.g., DLG4, EGFR, RAC1, SYK, PTK2B, SOCS1). Furthermore, based on these putative targets, we could infer repositionable candidate-compounds for the disease (e.g., tamoxifen, bosutinib, and dasatinib).

CONCLUSIONS: Our deep learning-based computational framework could be a powerful tool to efficiently prioritize new therapeutic targets and enhance the drug repositioning strategy.

PMID:33941241 | DOI:10.1186/s13195-021-00826-3

Categories: Literature Watch

The Coronavirus Network Explorer: mining a large-scale knowledge graph for effects of SARS-CoV-2 on host cell function

Tue, 2021-05-04 06:00

BMC Bioinformatics. 2021 May 3;22(1):229. doi: 10.1186/s12859-021-04148-x.

ABSTRACT

BACKGROUND: Leveraging previously identified viral interactions with human host proteins, we apply a machine learning-based approach to connect SARS-CoV-2 viral proteins to relevant host biological functions, diseases, and pathways in a large-scale knowledge graph derived from the biomedical literature. Our goal is to explore how SARS-CoV-2 could interfere with various host cell functions, and to identify drug targets amongst the host genes that could potentially be modulated against COVID-19 by repurposing existing drugs. The machine learning model employed here involves gene embeddings that leverage causal gene expression signatures curated from literature. In contrast to other network-based approaches for drug repurposing, our approach explicitly takes the direction of effects into account, distinguishing between activation and inhibition.

RESULTS: We have constructed 70 networks connecting SARS-CoV-2 viral proteins to various biological functions, diseases, and pathways reflecting viral biology, clinical observations, and co-morbidities in the context of COVID-19. Results are presented in the form of interactive network visualizations through a web interface, the Coronavirus Network Explorer (CNE), that allows exploration of underlying experimental evidence. We find that existing drugs targeting genes in those networks are strongly enriched in the set of drugs that are already in clinical trials against COVID-19.

CONCLUSIONS: The approach presented here can identify biologically plausible hypotheses for COVID-19 pathogenesis, explicitly connected to the immunological, virological and pathological observations seen in SARS-CoV-2 infected patients. The discovery of repurposable drugs is driven by prior knowledge of relevant functional endpoints that reflect known viral biology or clinical observations, therefore suggesting potential mechanisms of action. We believe that the CNE offers relevant insights that go beyond more conventional network approaches, and can be a valuable tool for drug repurposing. The CNE is available at https://digitalinsights.qiagen.com/coronavirus-network-explorer .

PMID:33941085 | DOI:10.1186/s12859-021-04148-x

Categories: Literature Watch

<em>In silico</em> identification and validation of triarylchromones as potential inhibitor against main protease of severe acute respiratory syndrome coronavirus 2

Mon, 2021-05-03 06:00

J Biomol Struct Dyn. 2021 May 3:1-16. doi: 10.1080/07391102.2021.1918255. Online ahead of print.

ABSTRACT

The ongoing pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused COVID-19 has emerged as a severe threat to the life of human kind. The identification and designing of appropriate and reliable drug molecule for the treatment of COVID-19 patients is the pressing need of the present time. Among different drug targets, the main protease of SARS-CoV-2 is being considered as most effective target. In addition to the drug repurposing, different compounds of natural as well as synthetic origins are being investigated for their efficacy against different drug targets of SARS-CoV-2 virus. In that context, the chromone based natural flavonols have also exhibited significant antiviral properties against different targets of SARS-CoV-2. The in silico studies presented here discloses the efficacy of triarylchromones (TAC) as potential inhibitor against main protease of SARS-CoV-2. The molecular docking and ADMET study performed using 14 arylchromones which could easily be accessed through simple synthetic protocols, revealed best binding affinities in case of TAC-3 (-11.2 kcal/mol), TAC-4 (-10.5 kcal/mol), TAC-6 (-11.2 kcal/mol), TAC-7 (-10.0 kcal/mol). Additional validation studies including molecular dynamics simulation and binding energy calculation using MMGBSA for protein ligand complex for 100 ns revealed the best binding interaction of TAC-3, TAC-4, TAC-6, TAC-7 against main protease of SARS-CoV-2. Moreover, the in vitro and preclinical validation of identified compounds will help us to understand the molecular mechanisms of regulation of TACs against SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

PMID:33939590 | DOI:10.1080/07391102.2021.1918255

Categories: Literature Watch

Resources and computational strategies to advance small molecule SARS-CoV-2 discovery: lessons from the pandemic and preparing for future health crises

Mon, 2021-05-03 06:00

Comput Struct Biotechnol J. 2021 Apr 26. doi: 10.1016/j.csbj.2021.04.059. Online ahead of print.

ABSTRACT

There is an urgent need to identify new therapies that prevent SARS-CoV-2 infection and improve the outcome of COVID-19 patients. This pandemic has thus spurred intensive research in most scientific areas and in a short period of time, several vaccines have been developed. But, while the race to find vaccines for COVID-19 has dominated the headlines, other types of therapeutic agents are being developed. In this mini-review, we report several databases and online tools that could assist the discovery of anti-SARS-CoV-2 small chemical compounds and peptides. We then give examples of studies that combined in silico and in vitro screening, either for drug repositioning purposes or to search for novel bioactive compounds. Finally, we question the overall lack of discussion and plan observed in academic research in many countries during this crisis and suggest that there is room for improvement.

PMID:33936562 | PMC:PMC8074526 | DOI:10.1016/j.csbj.2021.04.059

Categories: Literature Watch

In vitro susceptibility of human <em>Blastocystis</em> subtypes to simeprevir

Mon, 2021-05-03 06:00

Saudi J Biol Sci. 2021 Apr;28(4):2491-2501. doi: 10.1016/j.sjbs.2021.01.050. Epub 2021 Feb 2.

ABSTRACT

INTRODUCTION AND AIM: Blastocystis is a common enteric parasite, having a worldwide distribution. Many antimicrobial agents are effective against it, yet side effects and drug resistance have been reported. Thus, ongoing trials are being conducted for exploring anti-Blastocystis alternatives. Proteases are attractive anti-protozoal drug targets, having documented roles in Blastocystis. Serine proteases are present in both hepatitis C virus and Blastocystis. Since drug repositioning is quite trendy, the in vitro efficacy of simeprevir (SMV), an anti-hepatitis serine protease inhibitor, against Blastocystis was investigated in the current study.

METHODS: Stool samples were collected from patients, Alexandria, Egypt. Concentrated stools were screened using direct smears, trichrome, and modified Ziehl-Neelsen stains to exclude parasitic co-infections. Positive stool isolates were cultivated, molecularly subtyped for assessing the efficacy of three SMV doses (100,150, and 200 μg/ml) along 72 hours (h), on the most common subtype, through monitoring parasite growth, viability, re-culture, and also via ultrastructure verification. The most efficient dose and duration were later tested on other subtypes.

RESULTS: Results revealed that Blastocystis was detected in 54.17% of examined samples. Molecularly, ST3 predominated (62%), followed by ST1 (8.6%) and ST2 (3.4%). Ascending concentrations of SMV progressively inhibited growth, viability, and re-culture of treated Blastocystis, with a non-statistically significant difference when compared to the therapeutic control metronidazole (MTZ). The most efficient dose and duration against ST3 was 150 µg/ml for 72 h. This dose inhibited the growth of ST3, ST1, and ST2 with percentages of 95.19%, 94.83%, and 94.74%, successively and viability with percentages of 98.30%, 98.09%, and 97.96%, successively. This dose abolished Blastocystis upon re-culturing. Ultra-structurally, SMV induced rupture of Blastocystis cell membrane leading to necrotic death, versus the reported apoptotic death caused by MTZ. In conclusion, 150 µg/ml SMV for 72 h proved its efficacy against ST1, ST2, and ST3 Blastocystis, thus sparing the need for pre-treatment molecular subtyping in developing countries.

PMID:33935570 | PMC:PMC8071969 | DOI:10.1016/j.sjbs.2021.01.050

Categories: Literature Watch

In silico screening of potent bioactive compounds from honeybee products against COVID-19 target enzymes

Sun, 2021-05-02 06:00

Environ Sci Pollut Res Int. 2021 May 2. doi: 10.1007/s11356-021-14195-9. Online ahead of print.

ABSTRACT

After the early advent of the Coronavirus Disease 2019 (COVID-19) pandemic, myriads of FDA-approved drugs have been massively repurposed for COVID-19 treatment based on molecular docking against selected protein targets that play fundamental roles in the replication cycle of the novel coronavirus. Honeybee products are well known of their nutritional values and medicinal effects. Bee products contain bioactive compounds in the form of a collection of phenolic acids, flavonoids, and terpenes of natural origin that display wide spectrum antiviral effects. We revealed by molecular docking the profound binding affinity of 14 selected phenolics and terpenes present in honey and propolis (bees glue) against the main protease (Mpro) and RNA-dependent RNA polymerase (RdRp) enzymes of the novel SARS-CoV-2 virus (the causative agent of COVID-19) using AutoDock Vina software. Of these compounds, p-coumaric acid, ellagic acid, kaempferol, and quercetin have the strongest interaction with the SARS-CoV-2 target enzymes, and it may be considered an effective COVID-19 inhibitor.

PMID:33934306 | DOI:10.1007/s11356-021-14195-9

Categories: Literature Watch

A SARS-CoV-2 (COVID-19) biological network to find targets for drug repurposing

Sat, 2021-05-01 06:00

Sci Rep. 2021 Apr 30;11(1):9378. doi: 10.1038/s41598-021-88427-w.

ABSTRACT

The Coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus needs a fast recognition of effective drugs to save lives. In the COVID-19 situation, finding targets for drug repurposing can be an effective way to present new fast treatments. We have designed a two-step solution to address this approach. In the first step, we identify essential proteins from virus targets or their associated modules in human cells as possible drug target candidates. For this purpose, we apply two different algorithms to detect some candidate sets of proteins with a minimum size that drive a significant disruption in the COVID-19 related biological networks. We evaluate the resulted candidate proteins sets with three groups of drugs namely Covid-Drug, Clinical-Drug, and All-Drug. The obtained candidate proteins sets approve 16 drugs out of 18 in the Covid-Drug, 273 drugs out of 328 in the Clinical-Drug, and a large number of drugs in the All-Drug. In the second step, we study COVID-19 associated proteins sets and recognize proteins that are essential to disease pathology. This analysis is performed using DAVID to show and compare essential proteins that are contributed between the COVID-19 comorbidities. Our results for shared proteins show significant enrichment for cardiovascular-related, hypertension, diabetes type 2, kidney-related and lung-related diseases.

PMID:33931664 | DOI:10.1038/s41598-021-88427-w

Categories: Literature Watch

Repurposing of FDA-approved drugs as inhibitors of sterol C-24 methyltransferase of Leishmania donovani to fight against leishmaniasis

Fri, 2021-04-30 06:00

Drug Dev Res. 2021 Apr 30. doi: 10.1002/ddr.21820. Online ahead of print.

ABSTRACT

Leishmaniasis is a vector-borne disease caused by around 20 species of Leishmania. The main clinical forms of leishmaniasis are cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). VL is caused by Leishmania infantum in Central and South America, Mediterranean Basin, Middle East, and by L. donovani in Asia and Africa. Sterol C-24 methyltransferase (LdSMT) of L. donovani is a transferase enzyme of the sterol biosynthesis pathway. This pathway is one of the major targets for drug developments in Leishmania. Due to insufficient evidence about the exact function of SMT inside the cell and the uniqueness of the SMT enzyme in the Leishmania parasites made it a significant target for an effective drug development approach. We performed virtual screening of the Food and Drug Administration (FDA)-approved drug library against LdSMT and found simeprevir, an antiviral drug on top in the binding score. It showed a significant binding affinity with LdSMT. The binding was supported by hydrogen bonds and several other interactions. Simeprevir inhibited L. donovani growth of promastigotes with 50% inhibitory concentration (IC50 ) of 51.49 ± 5.87 μM. Further studies showed that simeprevir induced ROS generation in 44.7% of parasites at 125-μM concentration. Here, we for the first time reported simeprevir as an antileishmanial lead molecule using a drug repurposing approach.

PMID:33929761 | DOI:10.1002/ddr.21820

Categories: Literature Watch

In a search for potential drug candidates for combating COVID-19: computational study revealed salvianolic acid B as a potential therapeutic targeting 3CLpro and spike proteins

Fri, 2021-04-30 06:00

J Biomol Struct Dyn. 2021 Apr 30:1-28. doi: 10.1080/07391102.2021.1918256. Online ahead of print.

ABSTRACT

The global prevalence of COVID-19 disease and the overwhelming increase in death toll urge scientists to discover new effective drugs. Although the drug discovery process is a challenging and time-consuming, fortunately, the plant kingdom was found to have many active therapeutics possessing broad-spectrum antiviral activity including those candidates active against severe acute respiratory syndrome coronaviruses (SARS-CoV). Herein, nine traditional Chinese medicinal plant constituents from different origins (Glycyrrhizin 1, Lycorine 2, Puerarin 3, Daidzein 4, Daidzin 5, Salvianolic acid B 6, Dihydrotanshinone I 7, Tanshinone I 8, Tanshinone IIa 9) previously reported to exhibit antiviral activity against SARS-CoV were virtually screened in silico (molecular docking) as potential inhibitors of SARS-CoV-2 target proteins. The tested medicinal plant compounds were in silico screened for their activity against two key SARS-CoV-2 target proteins; 3CLpro, and Spike binding-domain proteins. Among the tested medicinal plant compounds, Salvianolic acid B 6 (Sal-B) showed promising binding affinities against the two specified SARS-CoV-2 target proteins compared to the reference standards used. Hence molecular dynamics simulations followed by calculating the free-binding energy were carried out for Sal-B providing information on its affinity, stability, and thermodynamic behavior within the two SARS-CoV-2 target proteins as well as key ligand-protein binding aspects. Besides, the quantum mechanical calculations showed that Sal-B can adopt different conformations due to the existence of various rotatable bonds. Therefore, the enhanced antiviral activity of Sal-B among other studied compounds can be also attributed to the structural flexibility of Sal-B. Our study gives an explanation of the structure activity relationship required for targeting SARS-CoV-2 3CLpro and Spike proteins and also facilitates the future design and synthesis of new potential drugs exhibiting better affinity and specificity. Besides, an ADME study was carried out on screened compounds and reference controls revealing their pharmacokinetics properties.Communicated by Ramaswamy H. Sarma.

PMID:33928870 | DOI:10.1080/07391102.2021.1918256

Categories: Literature Watch

Repurposing Immunomodulatory Drugs to Combat Tuberculosis

Fri, 2021-04-30 06:00

Front Immunol. 2021 Apr 13;12:645485. doi: 10.3389/fimmu.2021.645485. eCollection 2021.

ABSTRACT

Tuberculosis (TB) is an infectious disease caused by an obligate intracellular pathogen, Mycobacterium tuberculosis (M.tb) and is responsible for the maximum number of deaths due to a single infectious agent. Current therapy for TB, Directly Observed Treatment Short-course (DOTS) comprises multiple antibiotics administered in combination for 6 months, which eliminates the bacteria and prevents the emergence of drug-resistance in patients if followed as prescribed. However, due to various limitations viz., severe toxicity, low efficacy and long duration; patients struggle to comply with the prescribed therapy, which leads to the development of drug resistance (DR). The emergence of resistance to various front-line anti-TB drugs urgently require the introduction of new TB drugs, to cure DR patients and to shorten the treatment course for both drug-susceptible and resistant populations of bacteria. However, the development of a novel drug regimen involving 2-3 new and effective drugs will require approximately 20-30 years and huge expenditure, as seen during the discovery of bedaquiline and delamanid. These limitations make the field of drug-repurposing indispensable and repurposing of pre-existing drugs licensed for other diseases has tremendous scope in anti-DR-TB therapy. These repurposed drugs target multiple pathways, thus reducing the risk of development of drug resistance. In this review, we have discussed some of the repurposed drugs that have shown very promising results against TB. The list includes sulfonamides, sulfanilamide, sulfadiazine, clofazimine, linezolid, amoxicillin/clavulanic acid, carbapenems, metformin, verapamil, fluoroquinolones, statins and NSAIDs and their mechanism of action with special emphasis on their immunomodulatory effects on the host to attain both host-directed and pathogen-targeted therapy. We have also focused on the studies involving the synergistic effect of these drugs with existing TB drugs in order to translate their potential as adjunct therapies against TB.

PMID:33927718 | PMC:PMC8076598 | DOI:10.3389/fimmu.2021.645485

Categories: Literature Watch

Efficacy of Weight Reduction on Pediatric Nonalcoholic Fatty Liver Disease: Opportunities to Improve Treatment Outcomes Through Pharmacotherapy

Fri, 2021-04-30 06:00

Front Endocrinol (Lausanne). 2021 Apr 13;12:663351. doi: 10.3389/fendo.2021.663351. eCollection 2021.

ABSTRACT

Obesity is the single greatest risk factor for nonalcoholic fatty liver disease (NAFLD). Without intervention, most pediatric patients with NAFLD continue to gain excessive weight, making early, effective weight loss intervention key for disease treatment and prevention of NAFLD progression. Unfortunately, outside of a closely monitored research setting, which is not representative of the real world, lifestyle modification success for weight loss in children is low. Bariatric surgery, though effective, is invasive and can worsen NAFLD postoperatively. Thus, there is an evolving and underutilized role for pharmacotherapy in children, both for weight reduction and NAFLD management. In this perspective article, we provide an overview of the efficacy of weight reduction on pediatric NAFLD treatment, discuss the pros and cons of currently approved pharmacotherapy options, as well as drugs commonly used off-label for weight reduction in children and adolescents. We also highlight gaps in, and opportunities for, streamlining obesity trials to include NAFLD assessment as a valuable, secondary, therapeutic outcome measure, which may aid drug repurposing. Finally, we describe the already available, and emerging, minimally-invasive biomarkers of NAFLD that could offer a safe and convenient alternative to liver biopsy in pediatric obesity and NAFLD trials.

PMID:33927697 | PMC:PMC8076784 | DOI:10.3389/fendo.2021.663351

Categories: Literature Watch

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