1
|
Barrett MP. Transforming the chemotherapy of human African trypanosomiasis. Clin Microbiol Rev 2025; 38:e0015323. [PMID: 39772631 PMCID: PMC11905362 DOI: 10.1128/cmr.00153-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2025] Open
Abstract
SUMMARYPrior to 2019, when the orally available drug fexinidazole began its clinical use, the treatment of human African trypanosomiasis (HAT) was complex and unsatisfactory for many reasons. Two sub-species of the Trypanosoma brucei parasite are responsible for HAT, namely the rhodesiense form found in East and Southern Africa and the gambiense form found in Central and West Africa. Diseases caused by both forms manifest in two stages: stage 1 before and stage 2 after central nervous system involvement. Prior to 2019, different drugs were required for each of the two parasite sub-species at each stage. Gambiense disease required pentamidine or nifurtimox-eflornithine combination therapy, while for rhodesiense disease, suramin or melarsoprol was given for stages 1 and 2, respectively. These drugs all suffered complications including protracted administration regimens involving multiple injections with drug-induced adverse effects common. Today, a single drug, fexinidazole, can be given orally in most cases for both diseases at either stage. Another compound, acoziborole, effective in both stages 1 and 2 gambiense disease with a single dosing is anticipated to become available within a few years. Moreover, the recent engagement of multilateral organizations in seeking other compounds that could be used in HAT therapy has also been successful, and a rich vein of new trypanocides has been discovered. Here, the clinical use, modes of action, and resistance risks for drugs used against HAT are discussed.
Collapse
Affiliation(s)
- Michael P. Barrett
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
2
|
Carbajo CG, Han X, Savur B, Upadhyaya A, Taha F, Tinti M, Wheeler RJ, Yates PA, Tiengwe C. A high-throughput protein tagging toolkit that retains endogenous untranslated regions for studying gene regulation in kinetoplastids. Open Biol 2025; 15:240334. [PMID: 39999874 PMCID: PMC11858757 DOI: 10.1098/rsob.240334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2024] [Revised: 01/02/2025] [Accepted: 01/29/2025] [Indexed: 02/27/2025] Open
Abstract
Kinetoplastid parasites cause diseases that threaten human and animal health. To survive transitions between vertebrate hosts and insect vectors, these parasites rely on precise regulation of gene expression to adapt to environmental changes. Since gene regulation in kinetoplastids is primarily post-transcriptional, developing efficient genetic tools for modifying genes at their endogenous loci while preserving regulatory mRNA elements is crucial for studying their complex biology. We present a CRISPR/Cas9-based tagging system that preserves untranslated regulatory elements and uses a viral 2A peptide from Thosea asigna to generate two separate proteins from a single transcript: a drug-selectable marker and a tagged protein of interest. This dual-function design maintains native control elements, allowing discrimination between regulation of transcript abundance, translational efficiency, and post-translational events. We validate the system by tagging six Trypanosoma brucei proteins and demonstrate (i) high-efficiency positive selection and separation of drug-selectable marker and target protein, (ii) preservation of regulatory responses to environmental cues like heat shock and iron availability, and (iii) maintenance of stage-specific regulation during developmental transitions. This versatile toolkit is applicable to all kinetoplastids amenable to CRISPR/Cas9 editing, providing a powerful reverse genetic tool for studying post-transcriptional regulation and protein function in organisms where post-transcriptional control is dominant.
Collapse
Affiliation(s)
| | - Xiaoyang Han
- Department of Life Sciences, Imperial College London, London, UK
| | - Bhairavi Savur
- Department of Life Sciences, Imperial College London, London, UK
| | - Arushi Upadhyaya
- Department of Life Sciences, Imperial College London, London, UK
| | - Fatima Taha
- Department of Life Sciences, Imperial College London, London, UK
| | - Michele Tinti
- Wellcome Trust Centre for Anti-Infectives Research, University of Dundee, Dundee, UK
| | - Richard J. Wheeler
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, UK
| | - Phillip A. Yates
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, USA
| | - Calvin Tiengwe
- Department of Life Sciences, Imperial College London, London, UK
| |
Collapse
|
3
|
Carbajo CG, Han X, Savur B, Upadhyaya A, Taha F, Tinti M, Wheeler RJ, Yates PA, Tiengwe C. A high-throughput protein tagging toolkit that retains endogenous UTRs for studying gene regulation in Kinetoplastids. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.11.02.621556. [PMID: 39554005 PMCID: PMC11566017 DOI: 10.1101/2024.11.02.621556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2024]
Abstract
Kinetoplastid parasites cause diseases that threaten human and animal health. To survive transitions between vertebrate hosts and insect vectors, these parasites rely on precise regulation of gene expression to adapt to environmental changes. Since gene regulation in Kinetoplastids is primarily post-transcriptional, developing efficient genetic tools for modifying genes at their endogenous loci while preserving regulatory mRNA elements is crucial for studying their complex biology. We present a CRISPR/Cas9-based tagging system that preserves untranslated regulatory elements and uses a viral 2A peptide from Thosea asigna to generate two separate proteins from a single transcript: a drug-selectable marker and a tagged protein of interest. This dual-function design maintains native control elements, allowing discrimination between regulation of transcript abundance, translational efficiency, and post-translational events. We validate the system by tagging six Trypanosoma brucei proteins and demonstrate: (i) high-efficiency positive selection and separation of drug-selectable marker and target protein, (ii) preservation of regulatory responses to environmental cues like heat shock and iron availability, and (iii) maintenance of stage-specific regulation during developmental transitions. This versatile toolkit is applicable to all kinetoplastids amenable to CRISPR/Cas9 editing, providing a powerful reverse genetic tool for studying post-transcriptional regulation and protein function in organisms where post-transcriptional control is dominant.
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Sánchez-Salvador A, González-de la Fuente S, Aguado B, Yates PA, Requena JM. Refinement of Leishmania donovani Genome Annotations in the Light of Ribosome-Protected mRNAs Fragments (Ribo-Seq Data). Genes (Basel) 2023; 14:1637. [PMID: 37628688 PMCID: PMC10454037 DOI: 10.3390/genes14081637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Advances in next-generation sequencing methodologies have facilitated the assembly of an ever-increasing number of genomes. Gene annotations are typically conducted via specialized software, but the most accurate results require additional manual curation that incorporates insights derived from functional and bioinformatic analyses (e.g., transcriptomics, proteomics, and phylogenetics). In this study, we improved the annotation of the Leishmania donovani (strain HU3) genome using publicly available data from the deep sequencing of ribosome-protected mRNA fragments (Ribo-Seq). As a result of this analysis, we uncovered 70 previously non-annotated protein-coding genes and improved the annotation of around 600 genes. Additionally, we present evidence for small upstream open reading frames (uORFs) in a significant number of transcripts, indicating their potential role in the translational regulation of gene expression. The bioinformatics pipelines developed for these analyses can be used to improve the genome annotations of other organisms for which Ribo-Seq data are available. The improvements provided by these studies will bring us closer to the ultimate goal of a complete and accurately annotated L. donovani genome and will enhance future transcriptomics, proteomics, and genetics studies.
Collapse
Affiliation(s)
- Alejandro Sánchez-Salvador
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Departamento de Biología Molecular, Instituto Universitario de Biología Molecular (IUBM), Universidad Autónoma de Madrid, 28049 Madrid, Spain;
| | - Sandra González-de la Fuente
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Genomic and NGS Facility (GENGS), 28049 Madrid, Spain; (S.G.-d.l.F.); (B.A.)
| | - Begoña Aguado
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Genomic and NGS Facility (GENGS), 28049 Madrid, Spain; (S.G.-d.l.F.); (B.A.)
| | - Phillip A. Yates
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA
| | - Jose M. Requena
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Departamento de Biología Molecular, Instituto Universitario de Biología Molecular (IUBM), Universidad Autónoma de Madrid, 28049 Madrid, Spain;
- Centro de Investigación Biomédica en Red (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| |
Collapse
|
6
|
Mukherjee A, Hossain Z, Erben E, Ma S, Choi JY, Kim HS. Identification of a small-molecule inhibitor that selectively blocks DNA-binding by Trypanosoma brucei replication protein A1. Nat Commun 2023; 14:4390. [PMID: 37474515 PMCID: PMC10359466 DOI: 10.1038/s41467-023-39839-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 06/30/2023] [Indexed: 07/22/2023] Open
Abstract
Replication Protein A (RPA) is a broadly conserved complex comprised of the RPA1, 2 and 3 subunits. RPA protects the exposed single-stranded DNA (ssDNA) during DNA replication and repair. Using structural modeling, we discover an inhibitor, JC-229, that targets RPA1 in Trypanosoma brucei, the causative parasite of African trypanosomiasis. The inhibitor is highly toxic to T. brucei cells, while mildly toxic to human cells. JC-229 treatment mimics the effects of TbRPA1 depletion, including DNA replication inhibition and DNA damage accumulation. In-vitro ssDNA-binding assays demonstrate that JC-229 inhibits the activity of TbRPA1, but not the human ortholog. Indeed, despite the high sequence identity with T. cruzi and Leishmania RPA1, JC-229 only impacts the ssDNA-binding activity of TbRPA1. Site-directed mutagenesis confirms that the DNA-Binding Domain A (DBD-A) in TbRPA1 contains a JC-229 binding pocket. Residue Serine 105 determines specific binding and inhibition of TbRPA1 but not T. cruzi and Leishmania RPA1. Our data suggest a path toward developing and testing highly specific inhibitors for the treatment of African trypanosomiasis.
Collapse
Affiliation(s)
- Aditi Mukherjee
- Public Health Research Institute, Rutgers Biomedical Health Sciences, Newark, NJ, 07103, USA
| | - Zakir Hossain
- Department of Chemistry and Biochemistry, Queens College, New York, NY, 11367, USA
| | - Esteban Erben
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Provincia de Buenos Aires, Argentina
- Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Provincia de Buenos Aires, Argentina
| | - Shuai Ma
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - Jun Yong Choi
- Department of Chemistry and Biochemistry, Queens College, New York, NY, 11367, USA.
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
| | - Hee-Sook Kim
- Public Health Research Institute, Rutgers Biomedical Health Sciences, Newark, NJ, 07103, USA.
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers Biomedical Health Sciences, Newark, NJ, 07103, USA.
| |
Collapse
|
7
|
Kasozi KI, MacLeod ET, Welburn SC. Systematic Review and Meta-Analysis on Human African Trypanocide Resistance. Pathogens 2022; 11:pathogens11101100. [PMID: 36297157 PMCID: PMC9612373 DOI: 10.3390/pathogens11101100] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/14/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
Background Human African trypanocide resistance (HATr) is a challenge for the eradication of Human African Trypansomiaisis (HAT) following the widespread emergence of increased monotherapy drug treatment failures against Trypanosoma brucei gambiense and T. b. rhodesiense that are associated with changes in pathogen receptors. Methods: Electronic searches of 12 databases and 3 Google search websites for human African trypanocide resistance were performed using a keyword search criterion applied to both laboratory and clinical studies. Fifty-one publications were identified and included in this study using the PRISMA checklist. Data were analyzed using RevMan and random effect sizes were computed for the statistics at the 95% confidence interval. Results: Pentamidine/melarsoprol/nifurtimox cross-resistance is associated with loss of the T. brucei adenosine transporter 1/purine 2 gene (TbAT1/P2), aquaglyceroporins (TbAQP) 2 and 3, followed by the high affinity pentamidine melarsoprol transporter (HAPT) 1. In addition, the loss of the amino acid transporter (AAT) 6 is associated with eflornithine resistance. Nifurtimox/eflornithine combination therapy resistance is associated with AAT6 and nitroreductase loss, and high resistance and parasite regrowth is responsible for treatment relapse. In clinical studies, the TbAT1 proportion of total random effects was 68% (95% CI: 38.0−91.6); I2 = 96.99% (95% CI: 94.6−98.3). Treatment failure rates were highest with melarsoprol followed by eflornithine at 41.49% (95% CI: 24.94−59.09) and 6.56% (3.06−11.25) respectively. HATr-resistant phenotypes used in most laboratory experiments demonstrated significantly higher pentamidine resistance than other trypanocides. Conclusion: The emergence of drug resistance across the spectrum of trypanocidal agents that are used to treat HAT is a major threat to the global WHO target to eliminate HAT by 2030. T. brucei strains were largely resistant to diamidines and the use of high trypanocide concentrations in clinical studies have proved fatal in humans. Studies to develop novel chemotherapeutical agents and identify alternative protein targets could help to reduce the emergence and spread of HATr.
Collapse
Affiliation(s)
- Keneth Iceland Kasozi
- Infection Medicine, Deanery of Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh EH8 9JZ, UK
- School of Medicine, Kabale University, Kabale P.O. Box 317, Uganda
- Correspondence: (K.I.K.); (S.C.W.)
| | - Ewan Thomas MacLeod
- Infection Medicine, Deanery of Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Susan Christina Welburn
- Infection Medicine, Deanery of Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh EH8 9JZ, UK
- Zhejiang University-University of Edinburgh Joint Institute, Zhejiang University, International Campus, 718 East Haizhou Road, Haining 314400, China
- Correspondence: (K.I.K.); (S.C.W.)
| |
Collapse
|
8
|
Sáez Conde J, Dean S. Structure, function and druggability of the African trypanosome flagellum. J Cell Physiol 2022; 237:2654-2667. [PMID: 35616248 PMCID: PMC9323424 DOI: 10.1002/jcp.30778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022]
Abstract
African trypanosomes are early branching protists that cause human and animal diseases, termed trypanosomiases. They have been under intensive study for more than 100 years and have contributed significantly to our understanding of eukaryotic biology. The combination of conserved and parasite-specific features mean that their flagellum has gained particular attention. Here, we discuss the different structural features of the flagellum and their role in transmission and virulence. We highlight the possibilities of targeting flagellar function to cure trypanosome infections and help in the fight to eliminate trypanosomiases.
Collapse
Affiliation(s)
- Julia Sáez Conde
- Division of Biomedical Sciences, Warwick Medical SchoolUniversity of WarwickCoventryUK
| | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical SchoolUniversity of WarwickCoventryUK
| |
Collapse
|
9
|
Approaches to advance drug discovery for neglected tropical diseases. Drug Discov Today 2022; 27:2278-2287. [DOI: 10.1016/j.drudis.2022.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/21/2022] [Accepted: 04/02/2022] [Indexed: 12/19/2022]
|
10
|
Chkaiban L, Tosi L, Parekkadan B. Assembly of Long-Adapter Single-Strand Oligonucleotide (LASSO) Probes for Massively Parallel Capture of Kilobase Size DNA Targets. Curr Protoc 2021; 1:e278. [PMID: 34807521 PMCID: PMC8669654 DOI: 10.1002/cpz1.278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Genome DNA sequencing has become an affordable means to resolve questions about the genetic background of life. However, the biological functions of many DNA-encoded sequences are still relatively unknown. A highly scalable and cost-effective cloning method to select natural DNA targets from genomic templates is therefore urgently needed to enable rapid understanding of the biological products of genomes. One such method involves LASSO probes, which are long single-stranded DNA oligonucleotides designed with a universal adapter that is used to link two sequences that are complementary to a genomic target of interest. Through a pooled assembly method, LASSOs can be made for multiplex DNA capture. Herein, we describe a robust, efficient method to assemble LASSO probe libraries using a Cre-recombinase-mediated reaction and a protocol for multiplex genome target capture. The starting components are a pre-LASSO probe library comprising short DNA oligo pools designed in silico and an Escherichia coli plasmid (pLASSO) that incorporates the pre-LASSO library. Through internal recombination of pLASSO with its inserts, a mature LASSO library in final configuration can be made with high purity. Assembly of a LASSO probe library takes 4 days, and target capture can be performed in a single day. With an exponentially growing list of new genomes available for investigation, this method can enable the rapid production of ORFeome libraries for high-throughput screening to identify biological functions as a complementary approach to understand genome functional biology. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Assembly of LASSO probes Support Protocol 1: Generation of pLASSO vectors Support Protocol 2: Preparation of pre-LASSOs Basic Protocol 2: Massively parallel capture of large DNAs using LASSO probes.
Collapse
Affiliation(s)
- Lamia Chkaiban
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ
| | - Lorenzo Tosi
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ
| | - Biju Parekkadan
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ
| |
Collapse
|
11
|
Affiliation(s)
- Paula MacGregor
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- * E-mail:
| | | | - R. Ellen R. Nisbet
- School of Bioscience, University of Nottingham, Nottingham, United Kingdom
| |
Collapse
|
12
|
Horn D. Genome-scale RNAi screens in African trypanosomes. Trends Parasitol 2021; 38:160-173. [PMID: 34580035 DOI: 10.1016/j.pt.2021.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 12/11/2022]
Abstract
Genome-scale genetic screens allow researchers to rapidly identify the genes and proteins that impact a particular phenotype of interest. In African trypanosomes, RNA interference (RNAi) knockdown screens have revealed mechanisms underpinning drug resistance, drug transport, prodrug metabolism, quorum sensing, genome replication, and gene expression control. RNAi screening has also been remarkably effective at highlighting promising potential antitrypanosomal drug targets. The first ever RNAi library screen was implemented in African trypanosomes, and genome-scale RNAi screens and other related approaches continue to have a major impact on trypanosomatid research. Here, I review those impacts in terms of both discovery and translation.
Collapse
Affiliation(s)
- David Horn
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
| |
Collapse
|
13
|
Larson S, Carter M, Hovel-Miner G. Effects of trypanocidal drugs on DNA synthesis: new insights into melarsoprol growth inhibition. Parasitology 2021; 148:1143-1150. [PMID: 33593467 PMCID: PMC8292159 DOI: 10.1017/s0031182021000317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 12/14/2022]
Abstract
Trypanothione is the primary thiol redox carrier in Trypanosomatids whose biosynthesis and utilization pathways contain unique enzymes that include suitable drug targets against the human parasites in this family. Overexpression of the rate-limiting enzyme, γ-glutamylcysteine synthetase (GSH1), can increase the intracellular concentration of trypanothione. Melarsoprol directly inhibits trypanothione and has predicted the effects on downstream redox biology, including ROS management and dNTP synthesis that require further investigation. Thus, we hypothesized that melarsoprol treatment would inhibit DNA synthesis, which was tested using BrdU incorporation assays and cell cycle analyses. In addition, we analysed the effects of eflornithine, which interfaces with the trypanothione pathway, fexinidazole, because of the predicted effects on DNA synthesis, and pentamidine as an experimental control. We found that melarsoprol treatment resulted in a cell cycle stall and a complete inhibition of DNA synthesis within 24 h, which were alleviated by GSH1 overexpression. In contrast, the other drugs analysed had more subtle effects on DNA synthesis that were not significantly altered by GSH1 expression. Together these findings implicate DNA synthesis as a therapeutic target that warrants further investigation in the development of antitrypanosomal drugs.
Collapse
Affiliation(s)
- Stephen Larson
- Department of Microbiology, Immunology, & Tropical Medicine, The George Washington University, 2300 Eye Street NW, Ross Hall, Room 522, Washington, DC20037, USA
| | - McKenzie Carter
- Department of Microbiology, Immunology, & Tropical Medicine, The George Washington University, 2300 Eye Street NW, Ross Hall, Room 522, Washington, DC20037, USA
| | - Galadriel Hovel-Miner
- Department of Microbiology, Immunology, & Tropical Medicine, The George Washington University, 2300 Eye Street NW, Ross Hall, Room 522, Washington, DC20037, USA
| |
Collapse
|