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Zahedifard F, Bansal M, Sharma N, Kumar S, Shen S, Singh P, Rathi B, Zoltner M. Phenotypic screening reveals a highly selective phthalimide-based compound with antileishmanial activity. PLoS Negl Trop Dis 2024; 18:e0012050. [PMID: 38527083 PMCID: PMC10994559 DOI: 10.1371/journal.pntd.0012050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 04/04/2024] [Accepted: 03/05/2024] [Indexed: 03/27/2024] Open
Abstract
Pharmacophores such as hydroxyethylamine (HEA) and phthalimide (PHT) have been identified as potential synthons for the development of compounds against various parasitic infections. In order to further advance our progress, we conducted an experiment utilising a collection of PHT and HEA derivatives through phenotypic screening against a diverse set of protist parasites. This approach led to the identification of a number of compounds that exhibited significant effects on the survival of Entamoeba histolytica, Trypanosoma brucei, and multiple life-cycle stages of Leishmania spp. The Leishmania hits were pursued due to the pressing necessity to expand our repertoire of reliable, cost-effective, and efficient medications for the treatment of leishmaniases. Antileishmanials must possess the essential capability to efficiently penetrate the host cells and their compartments in the disease context, to effectively eliminate the intracellular parasite. Hence, we performed a study to assess the effectiveness of eradicating L. infantum intracellular amastigotes in a model of macrophage infection. Among eleven L. infantum growth inhibitors with low-micromolar potency, PHT-39, which carries a trifluoromethyl substitution, demonstrated the highest efficacy in the intramacrophage assay, with an EC50 of 1.2 +/- 3.2 μM. Cytotoxicity testing of PHT-39 in HepG2 cells indicated a promising selectivity of over 90-fold. A chemogenomic profiling approach was conducted using an orthology-based method to elucidate the mode of action of PHT-39. This genome-wide RNA interference library of T. brucei identified sensitivity determinants for PHT-39, which included a P-type ATPase that is crucial for the uptake of miltefosine and amphotericin, strongly indicating a shared route for cellular entry. Notwithstanding the favourable properties and demonstrated efficacy in the Plasmodium berghei infection model, PHT-39 was unable to eradicate L. major infection in a murine infection model of cutaneous leishmaniasis. Currently, PHT-39 is undergoing derivatization to optimize its pharmacological characteristics.
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Affiliation(s)
- Farnaz Zahedifard
- Drug Discovery and Evaluation Unit, Department of Parasitology, Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
| | - Meenakshi Bansal
- H. G. Khorana Centre for Chemical Biology, Department of Chemistry, Hansraj College, University of Delhi, Delhi, India
- Department of Chemistry, Deenbandhu Chhotu Ram, University of Science & Technology, Murthal, Sonepat Haryana, India
| | - Neha Sharma
- H. G. Khorana Centre for Chemical Biology, Department of Chemistry, Hansraj College, University of Delhi, Delhi, India
| | - Sumit Kumar
- Department of Chemistry, Deenbandhu Chhotu Ram, University of Science & Technology, Murthal, Sonepat Haryana, India
| | - Siqi Shen
- Drug Discovery and Evaluation Unit, Department of Parasitology, Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
| | - Priyamvada Singh
- Department of Chemistry, Miranda House, University of Delhi, Delhi, India
- Delhi School of Public Health, Institution of Eminence, University of Delhi, Delhi, India
| | - Brijesh Rathi
- H. G. Khorana Centre for Chemical Biology, Department of Chemistry, Hansraj College, University of Delhi, Delhi, India
- Delhi School of Public Health, Institution of Eminence, University of Delhi, Delhi, India
| | - Martin Zoltner
- Drug Discovery and Evaluation Unit, Department of Parasitology, Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
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Zoltner M, Leung KF, Alsford S, Horn D, Field MC. Modulation of the Surface Proteome through Multiple Ubiquitylation Pathways in African Trypanosomes. PLoS Pathog 2015; 11:e1005236. [PMID: 26492041 PMCID: PMC4619645 DOI: 10.1371/journal.ppat.1005236] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 09/28/2015] [Indexed: 12/29/2022] Open
Abstract
Recently we identified multiple suramin-sensitivity genes with a genome wide screen in Trypanosoma brucei that includes the invariant surface glycoprotein ISG75, the adaptin-1 (AP-1) complex and two deubiquitylating enzymes (DUBs) orthologous to ScUbp15/HsHAUSP1 and pVHL-interacting DUB1 (type I), designated TbUsp7 and TbVdu1, respectively. Here we have examined the roles of these genes in trafficking of ISG75, which appears key to suramin uptake. We found that, while AP-1 does not influence ISG75 abundance, knockdown of TbUsp7 or TbVdu1 leads to reduced ISG75 abundance. Silencing TbVdu1 also reduced ISG65 abundance. TbVdu1 is a component of an evolutionarily conserved ubiquitylation switch and responsible for rapid receptor modulation, suggesting similar regulation of ISGs in T. brucei. Unexpectedly, TbUsp7 knockdown also blocked endocytosis. To integrate these observations we analysed the impact of TbUsp7 and TbVdu1 knockdown on the global proteome using SILAC. For TbVdu1, ISG65 and ISG75 are the only significantly modulated proteins, but for TbUsp7 a cohort of integral membrane proteins, including the acid phosphatase MBAP1, that is required for endocytosis, and additional ISG-related proteins are down-regulated. Furthermore, we find increased expression of the ESAG6/7 transferrin receptor and ESAG5, likely resulting from decreased endocytic activity. Therefore, multiple ubiquitylation pathways, with a complex interplay with trafficking pathways, control surface proteome expression in trypanosomes. The mechanisms by which pathogens interact with their environment are of major importance, both for fulfilling the basic needs of the parasite and understanding immune evasion. For African trypanosomes, the surface is dominated by the variant surface glycoprotein (VSG), but recent data has demonstrated an important role for ubiquitylation in mediating turnover of invariant surface glycoproteins (ISGs) and maintaining ISG copy number independent of VSG. Further, ISG expression is required for suramin-sensitivity. Here we describe mechanisms mediating ISG turnover, uncovered using a screen for genes involved in sensitivity to suramin. These involve multiple aspects of the ubiquitylation machinery, and connect ISG turnover with additional surface proteins. Our data provide a first insight into the complexity of regulation of the ISG family, identifying further aspects to the control of a drug-sensitivity pathway in trypanosomes, and offering insights into metabolism of the parasite surface proteome.
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Affiliation(s)
- Martin Zoltner
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, United Kingdom
| | - Ka Fai Leung
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Sam Alsford
- London School of Hygiene and Tropical Medicine, Keppel Street, London, United Kingdom
| | - David Horn
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, United Kingdom
| | - Mark C. Field
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, United Kingdom
- * E-mail:
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