Pharmacophore Identification and Structure-Activity Relationship Analysis of a Series of Substituted Azaindoles as Inhibitors of .

Human African trypanosomiasis is among the World Health Organization's designated neglected tropical diseases. Repurposing strategies are often employed in academic drug discovery programs due to financial limitations, and in this instance, we used human kinase inhibitor chemotypes to identify substituted 4-aminoazaindoles, exemplified by . Structure-activity and structure-property relationship analysis, informed by cheminformatics, identified as a potent inhibitor of growth.

Repurposing the Open Global Health Library for the discovery of novel Mpro destabilizers with scope as broad-spectrum antivirals.

The SARS coronavirus 2 (SARS-CoV-2) epidemic remains globally active. The emergence of new variants of interest and variants of concern (VoCs), which are potentially more vaccine-resistant and less sensitive to existing treatments, is evident due to their high prevalence. The prospective spread of such variants and other coronaviruses with epidemic potential demands preparedness that can be met by developing fast-track workflows to find new candidates that target viral proteins with a clear and phenotype.

Collective and Diverted Total Synthesis of the Strasseriolides: A Family of Macrolides Endowed with Potent Antiplasmodial and Antitrypanosomal Activity.

The strasseriolide macrolides show promising in vitro and in vivo activities against P. falciparum and T. cruzi, the parasites causing malaria and Chagas disease, respectively.

Establishment of a screening platform based on human coronavirus OC43 for the identification of microbial natural products with antiviral activity.

The COVID-19 pandemic has revealed the lack of effective treatments against betacoronaviruses and the urgent need for new broad-spectrum antivirals. Natural products are a valuable source of bioactive compounds with pharmaceutical potential that may lead to the discovery of new antiviral agents. Specifically, compared to conventional synthetic molecules, microbial natural extracts possess a unique and vast chemical diversity and are amenable to large-scale production.

Corrigendum: Identification of novel anti-amoebic pharmacophores from kinase inhibitor chemotypes.

[This corrects the article DOI: 10.3389/fmicb.2023.

Strasseriolides display in vitro and in vivo activity against trypanosomal parasites and cause morphological and size defects in Trypanosoma cruzi.

Neglected diseases caused by kinetoplastid parasites are a health burden in tropical and subtropical countries. The need to create safe and effective medicines to improve treatment remains a priority. Microbial natural products are a source of chemical diversity that provides a valuable approach for identifying new drug candidates.

A nuclear orthologue of the dNTP triphosphohydrolase SAMHD1 controls dNTP homeostasis and genomic stability in .

Maintenance of dNTPs pools in is dependent on both biosynthetic and degradation pathways that together ensure correct cellular homeostasis throughout the cell cycle which is essential for the preservation of genomic stability. Both the salvage and pathways participate in the provision of pyrimidine dNTPs while purine dNTPs are made available solely through salvage. In order to identify enzymes involved in degradation here we have characterized the role of a trypanosomal SAMHD1 orthologue denominated TbHD82.

Identification of novel anti-amoebic pharmacophores from kinase inhibitor chemotypes.

species, , and are opportunistic pathogens that cause a range of brain, skin, eye, and disseminated diseases in humans and animals. These pathogenic free-living amoebae (pFLA) are commonly misdiagnosed and have sub-optimal treatment regimens which contribute to the extremely high mortality rates (>90%) when they infect the central nervous system. To address the unmet medical need for effective therapeutics, we screened kinase inhibitor chemotypes against three pFLA using phenotypic drug assays involving CellTiter-Glo 2.

Antiparasitic Meroterpenoids Isolated from CF-080171.

is a fungal genus from which a wide range of diverse biologically active compounds have been isolated. A CF-080171 extract was identified to exhibit potent activity against 3D7 and Tulahuen whole parasites in a high-throughput screening (HTS) campaign of microbial extracts from the Fundación MEDINA's collection. Bioassay-guided isolation of the active metabolites from this extract afforded eight new meroterpenoids of varying potencies, namely, memnobotrins C-E (-), a glycosylated isobenzofuranone (), a tricyclic isobenzofuranone (), a tetracyclic benzopyrane (), a tetracyclic isobenzofuranone (), and a pentacyclic isobenzofuranone ().

Inosine triphosphate pyrophosphatase from Trypanosoma brucei cleanses cytosolic pools from deaminated nucleotides.

Inosine triphosphate pyrophosphatases (ITPases) are ubiquitous house-cleaning enzymes that specifically recognize deaminated purine nucleotides and catalyze their hydrolytic cleavage. In this work, we have characterized the Trypanosoma brucei ITPase ortholog (TbITPA). Recombinant TbITPA efficiently hydrolyzes (deoxy)ITP and XTP nucleotides into their respective monophosphate form.

Preclinical evaluation of strasseriolides A-D, potent antiplasmodial macrolides isolated from Strasseria geniculata CF-247,251.

Background: Malaria is a global health problem for which novel therapeutic compounds are needed. To this end, a recently published novel family of antiplasmodial macrolides, strasseriolides A-D, was herein subjected to in vivo efficacy studies and preclinical evaluation in order to identify the most promising candidate(s) for further development.

Methods: Preclinical evaluation of strasseriolides A-D was performed by MTT-based cytotoxicity assay in THLE-2 (CRL-2706) liver cells, cardiotoxicity screening using the FluxOR™ potassium assay in hERG expressed HEK cells, LC-MS-based analysis of drug-drug interaction involving CYP3A4, CYP2D6 and CYP2C9 isoforms inhibition and metabolic stability assays in human liver microsomes.

New Compounds with Bioisosteric Replacement of Classic Choline Kinase Inhibitors Show Potent Antiplasmodial Activity.

In the fight against Malaria, new strategies need to be developed to avoid resistance of the parasite to pharmaceutics and other prevention barriers. Recently, a Host Directed Therapy approach based on the suppression of the starting materials uptake from the host by the parasite has provided excellent results. In this article, we propose the synthesis of bioisosteric compounds that are capable of inhibiting Choline Kinase and therefore to reduce choline uptake, which is essential for the development of the parasite.

Lead Optimization of 3,5-Disubstituted-7-Azaindoles for the Treatment of Human African Trypanosomiasis.

Neglected tropical diseases such as human African trypanosomiasis (HAT) are prevalent primarily in tropical climates and among populations living in poverty. Historically, the lack of economic incentive to develop new treatments for these diseases has meant that existing therapeutics have serious shortcomings in terms of safety, efficacy, and administration, and better therapeutics are needed. We now report a series of 3,5-disubstituted-7-azaindoles identified as growth inhibitors of , the parasite that causes HAT, through a high-throughput screen.

Structure-property studies of an imidazoquinoline chemotype with antitrypanosomal activity.

Human African trypanosomiasis is a neglected tropical disease (NTD) that is fatal if left untreated. Although approximately 13 million people live in moderate- to high-risk areas for infection, current treatments are plagued by problems with safety, efficacy, and emerging resistance. In an effort to fill the drug development pipeline for HAT, we have expanded previous work exploring the chemotype represented by the compound , with a particular focus on improvement of absorption, distribution, metabolism and elimination (ADME) properties.

A Mitochondrial Orthologue of the dNTP Triphosphohydrolase SAMHD1 Is Essential and Controls Pyrimidine Homeostasis in .

The maintenance of deoxyribonucleotide triphosphate (dNTP) homeostasis through synthesis and degradation is critical for accurate genomic and mitochondrial DNA replication fidelity. makes use of both the salvage and pathways for the provision of pyrimidine dNTPs. In this respect, the sterile α motif and histidine-aspartate domain-containing protein 1 (SAMHD1) appears to be the most relevant dNTPase controlling dNTP/deoxynucleoside homeostasis in mammalian cells.

Strasseriolides A-D, A Family of Antiplasmodial Macrolides Isolated from the Fungus CF-247251.

A novel family of four potent antimalarial macrolides, strasseriolides A-D (-), has been isolated from cultures of CF-247251, a fungal strain obtained from plant tissues. The structures of these compounds, including their absolute configurations, were elucidated by HRMS, NMR spectroscopy, and X-ray single-crystal diffraction. The four compounds gave respective IC values of 9.

Cytotoxycity and antiplasmodial activity of phenolic derivatives from Albizia zygia (DC.) J.F. Macbr. (Mimosaceae).

Background: The proliferation and resistance of microorganisms area serious threat against humankind and the search for new therapeutics is needed. The present report describes the antiplasmodial and anticancer activities of samples isolated from the methanol extract of Albizia zygia (Mimosaseae).

Material: The plant extract was prepared by maceration in methanol.

Quantitation of deoxynucleoside triphosphates by click reactions.

The levels of the four deoxynucleoside triphosphates (dNTPs) are under strict control in the cell, as improper or imbalanced dNTP pools may lead to growth defects and oncogenesis. Upon treatment of cancer cells with therapeutic agents, changes in the canonical dNTPs levels may provide critical information for evaluating drug response and mode of action. The radioisotope-labeling enzymatic assay has been commonly used for quantitation of cellular dNTP levels.

Selectivity and Physicochemical Optimization of Repurposed Pyrazolo[1,5-]pyridazines for the Treatment of Human African Trypanosomiasis.

From a high-throughput screen of 42 444 known human kinases inhibitors, a pyrazolo[1,5-]pyridazine scaffold was identified to begin optimization for the treatment of human African trypanosomiasis. Previously reported data for analogous compounds against human kinases GSK-3β, CDK-2, and CDK-4 were leveraged to try to improve the selectivity of the series, resulting in which showed selectivity for over these three human enzymes. In parallel, properties known to influence the absorption, distribution, metabolism, and excretion (ADME) profile of the series were optimized resulting in being progressed into an efficacy study in mice.

Validation of Plasmodium falciparum dUTPase as the target of 5'-tritylated deoxyuridine analogues with anti-malarial activity.

Background: Malaria remains as a major global problem, being one of the infectious diseases that engender highest mortality across the world. Due to the appearance of resistance and the lack of an effective vaccine, the search of novel anti-malarials is required. Deoxyuridine 5'-triphosphate nucleotido-hydrolase (dUTPase) is responsible for the hydrolysis of dUTP to dUMP within the parasite and has been proposed as an essential step in pyrimidine metabolism by providing dUMP for thymidylate biosynthesis.

Overview of the role of kinetoplastid surface carbohydrates in infection and host cell invasion: prospects for therapeutic intervention.

Kinetoplastid parasites are responsible for serious diseases in humans and livestock such as Chagas disease and sleeping sickness (caused by Trypanosoma cruzi and Trypanosoma brucei, respectively), and the different forms of cutaneous, mucocutaneous and visceral leishmaniasis (produced by Leishmania spp). The limited number of antiparasitic drugs available together with the emergence of resistance underscores the need for new therapeutic agents with novel mechanisms of action. The use of agents binding to surface glycans has been recently suggested as a new approach to antitrypanosomal design and a series of peptidic and non-peptidic carbohydrate-binding agents have been identified as antiparasitics showing efficacy in animal models of sleeping sickness.

Contribution of Cytidine Deaminase to Thymidylate Biosynthesis in Trypanosoma brucei: Intracellular Localization and Properties of the Enzyme.

Cytidine deaminase (CDA) is a pyrimidine salvage enzyme that catalyzes cytidine and deoxycytidine hydrolytic deamination to yield uridine and deoxyuridine. Here we report the biochemical characterization of CDA as an enzyme within the tetrameric class of the CDA family that efficiently deaminates cytidine, deoxycytidine, and the nucleoside analogue 5-methyl-2'-deoxycytidine. In line with previous studies, we show that RNA interference (RNAi)-mediated CDA depletion impairs proliferation when grown in pyrimidine-deficient medium, while supplementation with thymidine or deoxyuridine restores growth, further underscoring the role of this enzyme in providing deoxyuridine for dUMP formation via thymidine kinase, the substrate required for thymidylate biosynthesis.

DCTPP1 prevents a mutator phenotype through the modulation of dCTP, dTTP and dUTP pools.

To maintain dNTP pool homeostasis and preserve genetic integrity of nuclear and mitochondrial genomes, the synthesis and degradation of DNA precursors must be precisely regulated. Human all-alpha dCTP pyrophosphatase 1 (DCTPP1) is a dNTP pyrophosphatase with high affinity for dCTP and 5'-modified dCTP derivatives, but its contribution to overall nucleotide metabolism is controversial. Here, we identify a central role for DCTPP1 in the homeostasis of dCTP, dTTP and dUTP.

Evaluation of a class of isatinoids identified from a high-throughput screen of human kinase inhibitors as anti-Sleeping Sickness agents.

New treatments are needed for neglected tropical diseases (NTDs) such as Human African trypanosomiasis (HAT), Chagas disease, and schistosomiasis. Through a whole organism high-throughput screening campaign, we previously identified 797 human kinase inhibitors that grouped into 59 structural clusters and showed activity against T. brucei, the causative agent of HAT.

Base excision repair plays an important role in the protection against nitric oxide- and in vivo-induced DNA damage in Trypanosoma brucei.

Uracil-DNA glycosylase (UNG) initiates the base excision repair pathway by excising uracil from DNA. We have previously shown that Trypanosoma brucei cells defective in UNG exhibit reduced infectivity thus demonstrating the relevance of this glycosylase for survival within the mammalian host. In the early steps of the immune response, nitric oxide (NO) is released by phagocytes, which in combination with oxygen radicals produce reactive nitrogen species (RNS).