Scipion-Chem: An Open Platform for Virtual Drug Screening.

Virtual drug screening (VDS) tackles the problem of drug discovery by computationally reducing the number of potential pharmacological molecules that need to be tested experimentally to find a new drug. To do so, several approaches have been developed through the years, typically focusing on either the physicochemical characteristics of the receptor structure (structure-based virtual screening) or those of the potential ligands (ligand-based virtual screening). Scipion is a workflow engine well suited for structural studies of biological macromolecules. Here, we present Scipion-chem, a new branch oriented to VDS. A total of 11 plugins have already been integrated from the most common programs used in the field. They can be used through the Scipion graphical user interface to execute and analyze typical VDS tasks. In addition, we have developed several consensus protocols that combine results from the different integrated programs to generate more robust predictions. Backstage, Scipion also facilitates the interoperability of those different software packages while tracking all of the intermediate files, parameters, and user decisions. In summary, in this article, we present Scipion-chem. This accessible, interoperable, and traceable platform provides the user with all of the tools to carry out a successful VDS workflow. Scipion-chem is openly available at https://github.com/scipion-chem.

Benzodioxane-Benzamides as FtsZ Inhibitors: Effects of Linker's Functionalization on Gram-Positive Antimicrobial Activity.

FtsZ is an essential bacterial protein abundantly studied as a novel and promising target for antimicrobials. FtsZ is highly conserved among bacteria and mycobacteria, and it is crucial for the correct outcome of the cell division process, as it is responsible for the division of the parent bacterial cell into two daughter cells. In recent years, the benzodioxane-benzamide class has emerged as very promising and capable of targeting both Gram-positive and Gram-negative FtsZs. In this study, we explored the effect of including a substituent on the ethylenic linker between the two main moieties on the antimicrobial activity and pharmacokinetic properties. This substitution, in turn, led to the generation of a second stereogenic center, with both erythro and threo isomers isolated, characterized, and evaluated. With this work, we discovered how the hydroxy group slightly affects the antimicrobial activity, while being an important anchor for the exploitation and development of prodrugs, probes, and further derivatives.

N'-Phenylacetohydrazide Derivatives as Potent Ebola Virus Entry Inhibitors with an Improved Pharmacokinetic Profile.

Ebola virus (EBOV) is a single-strand RNA virus belonging to the Filoviridae family, which has been associated to most Ebola virus disease outbreaks to date, including the West African and the North Kivu epidemics between 2013 and 2022. This unprecedented health emergency prompted the search for effective medical countermeasures. Following up on the carbazole hit identified in our previous studies, we synthetized a new series of compounds, which demonstrated to prevent EBOV infection in cells by acting as virus entry inhibitors. The in vitro inhibitory activity was evaluated through the screening against surrogate models based on viral pseudotypes and further confirmed using replicative EBOV. Docking and molecular dynamics simulations joined to saturation transfer difference-nuclear magnetic resonance (STD-NMR) and mutagenesis experiments to elucidate the biological target of the most potent compounds. Finally, in vitro metabolic stability and in vivo pharmacokinetic studies were performed to confirm their therapeutic potential.

Design of New Dispersants Using Machine Learning and Visual Analytics.

Artificial intelligence (AI) is an emerging technology that is revolutionizing the discovery of new materials. One key application of AI is virtual screening of chemical libraries, which enables the accelerated discovery of materials with desired properties. In this study, we developed computational models to predict the dispersancy efficiency of oil and lubricant additives, a critical property in their design that can be estimated through a quantity named blotter spot. We propose a comprehensive approach that combines machine learning techniques with visual analytics strategies in an interactive tool that supports domain experts' decision-making. We evaluated the proposed models quantitatively and illustrated their benefits through a case study. Specifically, we analyzed a series of virtual polyisobutylene succinimide (PIBSI) molecules derived from a known reference substrate. Our best-performing probabilistic model was Bayesian Additive Regression Trees (BART), which achieved a mean absolute error of 5.50±0.34 and a root mean square error of 7.56±0.47, as estimated through 5-fold cross-validation. To facilitate future research, we have made the dataset, including the potential dispersants used for modeling, publicly available. Our approach can help accelerate the discovery of new oil and lubricant additives, and our interactive tool can aid domain experts in making informed decisions based on blotter spot and other key properties.

Multitarget drugs as potential therapeutic agents for alzheimer's disease. A new family of 5-substituted indazole derivatives as cholinergic and BACE1 inhibitors.

Multitarget drugs are a promising therapeutic approach against Alzheimer's disease. In this work, a new family of 5-substituted indazole derivatives with a multitarget profile including cholinesterase and BACE1 inhibition is described. Thus, the synthesis and evaluation of a new class of 5-substituted indazoles has been performed. Pharmacological evaluation includes in vitro inhibitory assays on AChE/BuChE and BACE1 enzymes. Also, the corresponding competition studies on BuChE were carried out. Additionally, antioxidant properties have been calculated from ORAC assays. Furthermore, studies of anti-inflammatory properties on Raw 264.7 cells and neuroprotective effects in human neuroblastoma SH-SY5Y cells have been performed. The results of pharmacological tests have shown that some of these 5-substituted indazole derivatives 1-4 and 6 behave as AChE/BuChE and BACE1 inhibitors, simultaneously. In addition, some indazole derivatives showed anti-inflammatory (3, 6) and neuroprotective (1-4 and 6) effects against Aß-induced cell death in human neuroblastoma SH-SY5Y cells with antioxidant properties.

Multitask Deep Neural Networks for Ames Mutagenicity Prediction.

The Ames mutagenicity test constitutes the most frequently used assay to estimate the mutagenic potential of drug candidates. While this test employs experimental results using various strains of Salmonella typhimurium, the vast majority of the published in silico models for predicting mutagenicity do not take into account the test results of the individual experiments conducted for each strain. Instead, such QSAR models are generally trained employing overall labels (i.e., mutagenic and nonmutagenic). Recently, neural-based models combined with multitask learning strategies have yielded interesting results in different domains, given their capabilities to model multitarget functions. In this scenario, we propose a novel neural-based QSAR model to predict mutagenicity that leverages experimental results from different strains involved in the Ames test by means of a multitask learning approach. To the best of our knowledge, the modeling strategy hereby proposed has not been applied to model Ames mutagenicity previously. The results yielded by our model surpass those obtained by single-task modeling strategies, such as models that predict the overall Ames label or ensemble models built from individual strains. For reproducibility and accessibility purposes, all source code and datasets used in our experiments are publicly available.

In Silico Analysis of Potential Drug Targets for Protozoan Infections.

BACKGROUND: Currently, protozoan infectious diseases affect billions of people every year. Their pharmacological treatments offer few alternatives and are restrictive due to undesirable side effects and parasite drug resistance. OBJECTIVE: In this work, three ontology-based approaches were used to identify shared potential drug targets in five species of protozoa. METHODS: In this study, proteomes of five species of protozoa: Entamoeba histolytica (E. histolytica), Giardia lamblia (G. lamblia), Trichomonas vaginalis (T. vaginalis), Trypanosoma cruzi (T. cruzi), and Leishmania mexicana (L. mexicana), were compared through orthology inference using three different tools to identify potential drug targets. RESULTS: Comparing the proteomes of E. histolytica, G. lamblia, T. vaginalis, T. cruzi, and L. mexicana, twelve targets for developing new drugs with antiprotozoal activity were identified. CONCLUSION: New drug targets were identified by orthology-based analysis; therefore, they could be considered for the development of new broad-spectrum antiprotozoal drugs. Particularly, triosephosphate isomerase emerges as a common target in trypanosomatids and amitochondriate parasites.

Naphthoquinone as a New Chemical Scaffold for Leishmanicidal Inhibitors of Leishmania GSK-3.

More than 1 billion people live in areas endemic for leishmaniasis, which is a relevant threat for public health worldwide. Due to the inadequate treatments, there is an urgent need to develop novel alternative drugs and to validate new targets to fight this disease. One appealing approach is the selective inhibition of protein kinases (PKs), enzymes involved in a wide range of processes along the life cycle of Leishmania. Several PKs, including glycogen synthase kinase 3 (GSK-3), have been validated as essential for this parasite by genetic or pharmacological methods. Recently, novel chemical scaffolds have been uncovered as Leishmania GSK-3 inhibitors with antiparasitic activity. In order to find new inhibitors of this enzyme, a virtual screening of our in-house chemical library was carried out on the structure of the Leishmania GSK-3. The virtual hits identified were experimentally assayed both for leishmanicidal activity and for in vitro inhibition of the enzyme. The best hits have a quinone scaffold. Their optimization through a medicinal chemistry approach led to a set of new compounds, provided a frame to establish biochemical and antiparasitic structure-activity relationships, and delivered molecules with an improved selectivity index. Altogether, this study paves the way for a systemic search of this class of inhibitors for further development as potential leishmanicidal drugs.

Identification of Niemann-Pick C1 protein as a potential novel SARS-CoV-2 intracellular target.

Niemann-Pick type C1 (NPC1) receptor is an endosomal membrane protein that regulates intracellular cholesterol traffic. This protein has been shown to play an important role for several viruses. It has been reported that SARS-CoV-2 enters the cell through plasma membrane fusion and/or endosomal entry upon availability of proteases. However, the whole process is not fully understood yet and additional viral/host factors might be required for viral fusion and subsequent viral replication. Here, we report a novel interaction between the SARS-CoV-2 nucleoprotein (N) and the cholesterol transporter NPC1. Furthermore, we have found that some compounds reported to interact with NPC1, carbazole SC816 and sulfides SC198 and SC073, were able to reduce SARS-CoV-2 viral infection with a good selectivity index in human cell infection models. These findings suggest the importance of NPC1 for SARS-CoV-2 viral infection and a new possible potential therapeutic target to fight against COVID-19.

AI in drug development: a multidisciplinary perspective.

The introduction of a new drug to the commercial market follows a complex and long process that typically spans over several years and entails large monetary costs due to a high attrition rate. Because of this, there is an urgent need to improve this process using innovative technologies such as artificial intelligence (AI). Different AI tools are being applied to support all four steps of the drug development process (basic research for drug discovery; pre-clinical phase; clinical phase; and postmarketing). Some of the main tasks where AI has proven useful include identifying molecular targets, searching for hit and lead compounds, synthesising drug-like compounds and predicting ADME-Tox. This review, on the one hand, brings in a mathematical vision of some of the key AI methods used in drug development closer to medicinal chemists and, on the other hand, brings the drug development process and the use of different models closer to mathematicians. Emphasis is placed on two aspects not mentioned in similar surveys, namely, Bayesian approaches and their applications to molecular modelling and the eventual final use of the methods to actually support decisions. Promoting a perfect synergy.

Virtual Screening of FDA-Approved Drugs against Triose Phosphate Isomerase from Entamoeba histolytica and Giardia lamblia Identifies Inhibitors of Their Trophozoite Growth Phase.

Infectious diseases caused by intestinal protozoan, such as Entamoeba histolytica (E. histolytica) and Giardia lamblia (G. lamblia) are a worldwide public health issue. They affect more than 70 million people every year. They colonize intestines causing primarily diarrhea; nevertheless, these infections can lead to more serious complications. The treatment of choice, metronidazole, is in doubt due to adverse effects and resistance. Therefore, there is a need for new compounds against these parasites. In this work, a structure-based virtual screening of FDA-approved drugs was performed to identify compounds with antiprotozoal activity. The glycolytic enzyme triosephosphate isomerase, present in both E. histolytica and G. lamblia, was used as the drug target. The compounds with the best average docking score on both structures were selected for the in vitro evaluation. Three compounds, chlorhexidine, tolcapone, and imatinib, were capable of inhibit growth on G. lamblia trophozoites (0.05-4.935 µg/mL), while folic acid showed activity against E. histolytica (0.186 µg/mL) and G. lamblia (5.342 µg/mL).

Potential pharmacological strategies targeting the Niemann-Pick C1 receptor and Ebola virus glycoprotein interaction.

Niemann-Pick C1 (NPC1) receptor is an intracellular protein located in late endosomes and lysosomes whose main function is to regulate intracellular cholesterol trafficking. Besides being postulated as necessary for the infection of highly pathogenic viruses in which the integrity of cholesterol transport is required, this protein also allows the entry of the Ebola virus (EBOV) into the host cells acting as an intracellular receptor. EBOV glycoprotein (EBOV-GP) interaction with NPC1 at the endosomal membrane triggers the release of the viral material into the host cell, starting the infective cycle. Disruption of the NPC1/EBOV-GP interaction could represent an attractive strategy for the development of drugs aimed at inhibiting viral entry and thus infection. Some of the today available EBOV inhibitors were proposed to interrupt this interaction, but molecular and structural details about their mode of action are still preliminary thus more efforts are needed to properly address these points. Here, we provide a critical discussion of the potential of NPC1 and its interaction with EBOV-GP as a therapeutic target for viral infections.

Host-Directed FDA-Approved Drugs with Antiviral Activity against SARS-CoV-2 Identified by Hierarchical In Silico/In Vitro Screening Methods.

The unprecedent situation generated by the COVID-19 global emergency has prompted us to actively work to fight against this pandemic by searching for repurposable agents among FDA approved drugs to shed light into immediate opportunities for the treatment of COVID-19 patients. In the attempt to proceed toward a proper rationalization of the search for new antivirals among approved drugs, we carried out a hierarchical in silico/in vitro protocol which successfully combines virtual and biological screening to speed up the identification of host-directed therapies against COVID-19 in an effective way. To this end a multi-target virtual screening approach focused on host-based targets related to viral entry, followed by the experimental evaluation of the antiviral activity of selected compounds, has been carried out. As a result, five different potentially repurposable drugs interfering with viral entry-cepharantine, clofazimine, metergoline, imatinib and efloxate-have been identified.

Identification of potential inhibitors of protein-protein interaction useful to fight against Ebola and other highly pathogenic viruses.

Despite the efforts to develop new treatments against Ebola virus (EBOV) there is currently no antiviral drug licensed to treat patients with Ebola virus disease (EVD). Therefore, there is still an urgent need to find new drugs to fight against EBOV. In order to do this, a virtual screening was done on the druggable interaction between the EBOV glycoprotein (GP) and the host receptor NPC1 with a subsequent selection of compounds for further validation. This screening led to the identification of new small organic molecules with potent inhibitory action against EBOV infection using lentiviral EBOV-GP-pseudotype viruses. Moreover, some of these compounds have shown their ability to interfere with the intracellular cholesterol transport receptor NPC1 using an ELISA-based assay. These preliminary results pave the way to hit to lead optimization programs that lead to successful candidates.

Discovery of Amoebicidal Compounds by Combining Computational and Experimental Approaches.

Pathogenic and opportunistic free-living amoebae such as Acanthamoeba spp. can cause keratitis (Acanthamoeba keratitis [AK]), which may ultimately lead to permanent visual impairment or blindness. Acanthamoeba can also cause rare but usually fatal granulomatous amoebic encephalitis (GAE). Current therapeutic options for AK require a lengthy treatment with nonspecific drugs that are often associated with adverse effects. Recent developments in the field led us to target cAMP pathways, specifically phosphodiesterase. Guided by computational tools, we targeted the Acanthamoeba phosphodiesterase RegA. Computational studies led to the construction and validation of a homology model followed by a virtual screening protocol guided by induced-fit docking and chemical scaffold analysis using our medicinal and biological chemistry (MBC) chemical library. Subsequently, 18 virtual screening hits were prioritized for further testing in vitro against Acanthamoeba castellanii, identifying amoebicidal hits containing piperidine and urea imidazole cores. Promising activities were confirmed in the resistant cyst form of the amoeba and in additional clinical Acanthamoeba strains, increasing their therapeutic potential. Mechanism-of-action studies revealed that these compounds produce apoptosis through reactive oxygen species (ROS)-mediated mitochondrial damage. These chemical families show promise for further optimization to produce effective antiacanthamoebal drugs.

COVID-19 Vaccine Race: Analysis of Age-Dependent Immune Responses against SARS-CoV-2 Indicates that more than Just One Strategy May Be Needed.

In December 2019, a novel respiratory coronavirus named SARS-CoV-2 appeared in China, causing the disease termed COVID-19 that has caused millions of infections worldwide. In this article, we have analyzed existing evidence on the immune response against SARS coronaviruses in order to understand the possible outcome of a vaccine for COVID-19. From our analysis, it becomes clear that there is a big difference in the immune response against SARS in children, young adults and the elderly, both at the innate and adaptive levels. Taking this information into account, we have studied the strategies that are being used for the development of COVID-19 vaccines. We discussed the perspectives for obtention and worldwide distribution of reliable vaccines using this perspective. The conclusion is that different vaccines may be protective for different age segments within the population, depending on the strategy used for their design. Therefore, it will become necessary for several vaccines to reach the finish line, not only to ensure availability, but also to guarantee an adequate immune response at the individual level.

New cannabinoid receptor antagonists as pharmacological tool.

Synthesis and pharmacological evaluation of a new series of cannabinoid receptor antagonists of indazole ether derivatives have been performed. Pharmacological evaluation includes radioligand binding assays with [3H]-CP55940 for CB1 and CB2 receptors and functional activity for cannabinoid receptors on isolated tissue. In addition, functional activity of the two synthetic cannabinoids antagonists 18 (PGN36) and 17 (PGN38) were carried out in the osteoblastic cell line MC3T3-E1 that is able to express CB2R upon osteogenic conditions. Both antagonists abolished the increase in collagen type I gene expression by the well-known inducer of bone activity, the HU308 agonist. The results of pharmacological tests have revealed that four of these derivatives behave as CB2R cannabinoid antagonists. In particular, the compounds 17 (PGN38) and 18 (PGN36) highlight as promising candidates as pharmacological tools.

Glycogen synthase kinase 3 (GSK-3) inhibitors: a patent update (2016-2019).

INTRODUCTION: Glycogen synthase kinase 3 (GSK-3) is a constitutively active, ubiquitous expressed ser/thr kinase that is involved in a large number of signaling pathways. GSK-3 is a key target of a remarkably large number of cellular processes and diseases such as diabetes type II, cancer, immune disorder, neurodegenerative pathologies among others diseases and surely in regenerative medicine. During the last decades the scientific community has been working to understand the role of GSK-3 with the aim in mind of design efficient and selectivity GSK-3 inhibitors (GSK3i). However so far clinical and preclinical GSK3i have been both sub-optimal regarding potency, poor GSK-3 selectivity over other CNS targets and closely related kinases, low CNS exposure, and chronic toxicity. Research into GSK inhibitors relay primarily on identification of the new use of the know GSK3i and the development of them in order to improve selectivity and toxicity. AREAS COVERED: This review covers patent literature on GSK3i and their application published between 2016 and 2019. EXPERT OPINION: Thanks to the past, present, and future research, in the next few years we will see progress in the treatment of some diseases with GSK3i, for instance in regenerative medicine immunotherapy applications among others.

COVID-19: Drug Targets and Potential Treatments.

Currently, humans are immersed in a pandemic caused by the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which threatens public health worldwide. To date, no drug or vaccine has been approved to treat the severe disease caused by this coronavirus, COVID-19. In this paper, we will focus on the main virus-based and host-based targets that can guide efforts in medicinal chemistry to discover new drugs for this devastating disease. In principle, all CoV enzymes and proteins involved in viral replication and the control of host cellular machineries are potentially druggable targets in the search for therapeutic options for SARS-CoV-2. This Perspective provides an overview of the main targets from a structural point of view, together with reported therapeutic compounds with activity against SARS-CoV-2 and/or other CoVs. Also, the role of innate immune response to coronavirus infection and the related therapeutic options will be presented.

Computational Drug Repositioning for Chagas Disease Using Protein-Ligand Interaction Profiling.

Chagas disease, caused by Trypanosoma cruzi (T. cruzi), affects nearly eight million people worldwide. There are currently only limited treatment options, which cause several side effects and have drug resistance. Thus, there is a great need for a novel, improved Chagas treatment. Bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) has emerged as a promising pharmacological target. Moreover, some human dihydrofolate reductase (HsDHFR) inhibitors such as trimetrexate also inhibit T. cruzi DHFR-TS (TcDHFR-TS). These compounds serve as a starting point and a reference in a screening campaign to search for new TcDHFR-TS inhibitors. In this paper, a novel virtual screening approach was developed that combines classical docking with protein-ligand interaction profiling to identify drug repositioning opportunities against T. cruzi infection. In this approach, some food and drug administration (FDA)-approved drugs that were predicted to bind with high affinity to TcDHFR-TS and whose predicted molecular interactions are conserved among known inhibitors were selected. Overall, ten putative TcDHFR-TS inhibitors were identified. These exhibited a similar interaction profile and a higher computed binding affinity, compared to trimetrexate. Nilotinib, glipizide, glyburide and gliquidone were tested on T. cruzi epimastigotes and showed growth inhibitory activity in the micromolar range. Therefore, these compounds could lead to the development of new treatment options for Chagas disease.