1
|
Woodland JG, Horatscheck A, Soares de Melo C, Dziwornu GA, Taylor D. Another decade of antimalarial drug discovery: New targets, tools and molecules. PROGRESS IN MEDICINAL CHEMISTRY 2024; 63:161-234. [PMID: 39370241 DOI: 10.1016/bs.pmch.2024.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/08/2024]
Abstract
Malaria remains a devastating but preventable infectious disease that disproportionately affects the African continent. Emerging resistance to current frontline therapies means that not only are new treatments urgently required, but also novel validated antimalarial targets to circumvent cross-resistance. Fortunately, tremendous efforts have been made by the global drug discovery community over the past decade. In this chapter, we will highlight some of the antimalarial drug discovery and development programmes currently underway across the globe, charting progress in the identification of new targets and the development of new classes of drugs to prosecute them. These efforts have been complemented by the development of valuable tools to accelerate target validation such as the NOD scid gamma (NSG) humanized mouse efficacy model and progress in predictive modelling and open-source software. Among the medicinal chemistry programmes that have been conducted over the past decade are those targeting Plasmodium falciparum ATPase4 (ATP4) and acetyl-CoA synthetase (AcAS) as well as proteins disrupting parasite protein translation such as the aminoacyl-tRNA synthetases (aaRSs) and eukaryotic elongation factor 2 (eEF2). The benefits and challenges of targeting Plasmodium kinases will be examined, with a focus on Plasmodium cyclic GMP-dependent protein kinase (PKG), cyclin-dependent-like protein kinase 3 (CLK3) and phosphatidylinositol 4-kinase (PI4K). The chapter concludes with a survey of incipient drug discovery centres in Africa and acknowledges the value of recent international meetings in galvanizing and uniting the antimalarial drug discovery community.
Collapse
Affiliation(s)
- John G Woodland
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - André Horatscheck
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch, South Africa
| | - Candice Soares de Melo
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch, South Africa
| | - Godwin A Dziwornu
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch, South Africa
| | - Dale Taylor
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch, South Africa.
| |
Collapse
|
2
|
Gupta A, Gonzalez-Chavez Z, Desai SA. Plasmodium falciparum CLAG Paralogs All Traffic to the Host Membrane but Knockouts Have Distinct Phenotypes. Microorganisms 2024; 12:1172. [PMID: 38930554 PMCID: PMC11205492 DOI: 10.3390/microorganisms12061172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
Malaria parasites increase their host erythrocyte's permeability to obtain essential nutrients from plasma and facilitate intracellular growth. In the human Plasmodium falciparum pathogen, this increase is mediated by the plasmodial surface anion channel (PSAC) and has been linked to CLAG3, a protein integral to the host erythrocyte membrane and encoded by a member of the conserved clag multigene family. Whether paralogs encoded by other clag genes also insert at the host membrane is unknown; their contributions to PSAC formation and other roles served are also unexplored. Here, we generated transfectant lines carrying epitope-tagged versions of each CLAG. Each paralog is colocalized with CLAG3, with concordant trafficking via merozoite rhoptries to the host erythrocyte membrane of newly invaded erythrocytes. Each also exists within infected cells in at least two forms: an alkaline-extractable soluble form and a form integral to the host membrane. Like CLAG3, CLAG2 has a variant region cleaved by extracellular proteases, but CLAG8 and CLAG9 are protease resistant. Paralog knockout lines, generated through CRISPR/Cas9 transfection, exhibited uncompromised growth in PGIM, a modified medium with higher physiological nutrient levels; this finding is in marked contrast to a recently reported CLAG3 knockout parasite. CLAG2 and CLAG8 knockout lines exhibited compensatory increases in the transcription of the remaining clags and associated rhoph genes, yielding increased PSAC-mediated uptake for specific solutes. We also report on the distinct transport properties of these knockout lines. Similar membrane topologies at the host membrane are consistent with each CLAG paralog contributing to PSAC, but other roles require further examination.
Collapse
Affiliation(s)
| | | | - Sanjay A. Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MA 20852, USA
| |
Collapse
|
3
|
Keroack CD, Elsworth B, Tennessen JA, Paul AS, Hua R, Ramirez-Ramirez L, Ye S, Moreira CK, Meyers MJ, Zarringhalam K, Duraisingh MT. Comparative chemical genomics in Babesia species identifies the alkaline phosphatase PhoD as a determinant of antiparasitic resistance. Proc Natl Acad Sci U S A 2024; 121:e2312987121. [PMID: 38377214 PMCID: PMC10907312 DOI: 10.1073/pnas.2312987121] [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: 08/07/2023] [Accepted: 01/09/2024] [Indexed: 02/22/2024] Open
Abstract
Babesiosis is an emerging zoonosis and widely distributed veterinary infection caused by 100+ species of Babesia parasites. The diversity of Babesia parasites and the lack of specific drugs necessitate the discovery of broadly effective antibabesials. Here, we describe a comparative chemogenomics (CCG) pipeline for the identification of conserved targets. CCG relies on parallel in vitro evolution of resistance in independent populations of Babesia spp. (B. bovis and B. divergens). We identified a potent antibabesial, MMV019266, from the Malaria Box, and selected for resistance in two species of Babesia. After sequencing of multiple independently derived lines in the two species, we identified mutations in a membrane-bound metallodependent phosphatase (phoD). In both species, the mutations were found in the phoD-like phosphatase domain. Using reverse genetics, we validated that mutations in bdphoD confer resistance to MMV019266 in B. divergens. We have also demonstrated that BdPhoD localizes to the endomembrane system and partially with the apicoplast. Finally, conditional knockdown and constitutive overexpression of BdPhoD alter the sensitivity to MMV019266 in the parasite. Overexpression of BdPhoD results in increased sensitivity to the compound, while knockdown increases resistance, suggesting BdPhoD is a pro-susceptibility factor. Together, we have generated a robust pipeline for identification of resistance loci and identified BdPhoD as a resistance mechanism in Babesia species.
Collapse
Affiliation(s)
- Caroline D. Keroack
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Brendan Elsworth
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Jacob A. Tennessen
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Aditya S. Paul
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Renee Hua
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Luz Ramirez-Ramirez
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Sida Ye
- Department of Mathematics, University of Massachusetts, Boston, MA02125
- Center for Personalized Cancer Therapy, University of Massachusetts, Boston, MA02125
| | - Cristina K. Moreira
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| | - Marvin J. Meyers
- Department of Chemistry, Saint Louis University, St. Louis, MO63103
| | - Kourosh Zarringhalam
- Department of Mathematics, University of Massachusetts, Boston, MA02125
- Center for Personalized Cancer Therapy, University of Massachusetts, Boston, MA02125
| | - Manoj T. Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA02115
| |
Collapse
|
4
|
Narsimulu B, Jakkula P, Qureshi R, Nasim F, Qureshi IA. Inhibition and structural insights of leishmanial glutamyl-tRNA synthetase for designing potent therapeutics. Int J Biol Macromol 2024; 254:127756. [PMID: 37907177 DOI: 10.1016/j.ijbiomac.2023.127756] [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] [Received: 07/12/2023] [Revised: 10/08/2023] [Accepted: 10/27/2023] [Indexed: 11/02/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRSs), essential components of the protein synthesizing machinery, have been often chosen for devising therapeutics against parasitic diseases. Due to their relevance in drug development, the current study was designed to explore functional and structural aspects of Leishmania donovani glutamyl-tRNA synthetase (LdGluRS). Hence, LdGluRS was cloned into an expression vector and purified to homogeneity using chromatographic techniques. Purified protein showed maximum enzymatic activity at physiological pH, with more binding capacity towards its cofactor (Adenosine triphosphate, 0.06 ± 0.01 mM) than the cognate substrate (L-glutamate, 9.5 ± 0.5 mM). Remarkably, salicylate inhibited LdGluRS competitively with respect to L-glutamate and exhibited druglikeness with negligible effect on human macrophages. The protein possessed more α-helices (43 %) than β-sheets (12 %), whereas reductions in thermal stability and cofactor-binding affinity, along with variation in mode of inhibition after mutation signified the role of histidine (H60) as a catalytic residue. LdGluRS could also generate a pro-inflammatory milieu in human macrophages by upregulating cytokines. The docking study demonstrated the placement of salicylate into LdGluRS substrate-binding site, and the complex was found to be stable during molecular dynamics (MD) simulation. Altogether, our study highlights the understanding of molecular inhibition and structural features of glutamyl-tRNA synthetase from kinetoplastid parasites.
Collapse
Affiliation(s)
- Bandigi Narsimulu
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Hyderabad 500046, India
| | - Pranay Jakkula
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Hyderabad 500046, India
| | - Rahila Qureshi
- Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500039, India
| | - Fouzia Nasim
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Hyderabad 500046, India
| | - Insaf Ahmed Qureshi
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Hyderabad 500046, India.
| |
Collapse
|
5
|
Bhowal P, Roy B, Ganguli S, Igloi GL, Banerjee R. Elucidating the structure-function attributes of a trypanosomal arginyl-tRNA synthetase. Mol Biochem Parasitol 2023; 256:111597. [PMID: 37852416 DOI: 10.1016/j.molbiopara.2023.111597] [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] [Received: 08/06/2023] [Revised: 09/20/2023] [Accepted: 10/10/2023] [Indexed: 10/20/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are fundamental components of the protein translation machinery. In light of their pivotal role in protein synthesis and structural divergence among species, they have always been considered potential targets for the development of antimicrobial compounds. Arginyl-tRNA synthetase from Trypanosoma cruzi (TcArgRS), the parasite responsible for causing Chagas Disease, contains a 100-amino acid insertion that was found to be completely absent in the human counterpart of similar length, as ascertained from multiple sequence alignment results. Thus, we were prompted to perform a preliminary characterization of TcArgRS using biophysical, biochemical, and bioinformatics tools. We expressed the protein in E. coli and validated its in-vitro enzymatic activity. Additionally, analysis of DTNB kinetics, Circular dichroism (CD) spectra, and ligand-binding studies using intrinsic tryptophan fluorescence measurements aided us to understand some structural features in the absence of available crystal structures. Our study indicates that TcArgRS can discriminate between L-arginine and its analogues. Among the many tested substrates, only L-canavanine and L-thioarginine, a synthetic arginine analogue exhibited notable activation. The binding of various substrates was also determined using in silico methods. This study may provide a viable foundation for studying small compounds that can be targeted against TcArgRS.
Collapse
Affiliation(s)
- Pratyasha Bhowal
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700 019, India
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Sayak Ganguli
- Post Graduate Department of Biotechnology, St. Xavier's College (Autonomous), 30, Park Street, Mullick Bazar, Kolkata 700 016, India.
| | - Gabor L Igloi
- Institute of Biology III, University of Freiburg, Schänzlestr 1, D-79104 Freiburg, Germany
| | - Rajat Banerjee
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700 019, India.
| |
Collapse
|
6
|
Viegas J. Profile of Daniel E. Goldberg. Proc Natl Acad Sci U S A 2023; 120:e2314435120. [PMID: 37722042 PMCID: PMC10523458 DOI: 10.1073/pnas.2314435120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023] Open
|
7
|
Xie SC, Griffin MDW, Winzeler EA, Ribas de Pouplana L, Tilley L. Targeting Aminoacyl tRNA Synthetases for Antimalarial Drug Development. Annu Rev Microbiol 2023; 77:111-129. [PMID: 37018842 DOI: 10.1146/annurev-micro-032421-121210] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Infections caused by malaria parasites place an enormous burden on the world's poorest communities. Breakthrough drugs with novel mechanisms of action are urgently needed. As an organism that undergoes rapid growth and division, the malaria parasite Plasmodium falciparum is highly reliant on protein synthesis, which in turn requires aminoacyl-tRNA synthetases (aaRSs) to charge tRNAs with their corresponding amino acid. Protein translation is required at all stages of the parasite life cycle; thus, aaRS inhibitors have the potential for whole-of-life-cycle antimalarial activity. This review focuses on efforts to identify potent plasmodium-specific aaRS inhibitors using phenotypic screening, target validation, and structure-guided drug design. Recent work reveals that aaRSs are susceptible targets for a class of AMP-mimicking nucleoside sulfamates that target the enzymes via a novel reaction hijacking mechanism. This finding opens up the possibility of generating bespoke inhibitors of different aaRSs, providing new drug leads.
Collapse
Affiliation(s)
- Stanley C Xie
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia; , ,
| | - Michael D W Griffin
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia; , ,
| | - Elizabeth A Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California, USA;
| | - Lluis Ribas de Pouplana
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain;
- Catalan Institution for Research and Advanced Studies, Barcelona, Catalonia, Spain
| | - Leann Tilley
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia; , ,
| |
Collapse
|
8
|
Kelsen A, Kent RS, Snyder AK, Wehri E, Bishop SJ, Stadler RV, Powell C, Martorelli di Genova B, Rompikuntal PK, Boulanger MJ, Warshaw DM, Westwood NJ, Schaletzky J, Ward GE. MyosinA is a druggable target in the widespread protozoan parasite Toxoplasma gondii. PLoS Biol 2023; 21:e3002110. [PMID: 37155705 PMCID: PMC10185354 DOI: 10.1371/journal.pbio.3002110] [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: 02/15/2023] [Revised: 05/15/2023] [Accepted: 04/05/2023] [Indexed: 05/10/2023] Open
Abstract
Toxoplasma gondii is a widespread apicomplexan parasite that can cause severe disease in its human hosts. The ability of T. gondii and other apicomplexan parasites to invade into, egress from, and move between cells of the hosts they infect is critical to parasite virulence and disease progression. An unusual and highly conserved parasite myosin motor (TgMyoA) plays a central role in T. gondii motility. The goal of this work was to determine whether the parasite's motility and lytic cycle can be disrupted through pharmacological inhibition of TgMyoA, as an approach to altering disease progression in vivo. To this end, we first sought to identify inhibitors of TgMyoA by screening a collection of 50,000 structurally diverse small molecules for inhibitors of the recombinant motor's actin-activated ATPase activity. The top hit to emerge from the screen, KNX-002, inhibited TgMyoA with little to no effect on any of the vertebrate myosins tested. KNX-002 was also active against parasites, inhibiting parasite motility and growth in culture in a dose-dependent manner. We used chemical mutagenesis, selection in KNX-002, and targeted sequencing to identify a mutation in TgMyoA (T130A) that renders the recombinant motor less sensitive to compound. Compared to wild-type parasites, parasites expressing the T130A mutation showed reduced sensitivity to KNX-002 in motility and growth assays, confirming TgMyoA as a biologically relevant target of KNX-002. Finally, we present evidence that KNX-002 can slow disease progression in mice infected with wild-type parasites, but not parasites expressing the resistance-conferring TgMyoA T130A mutation. Taken together, these data demonstrate the specificity of KNX-002 for TgMyoA, both in vitro and in vivo, and validate TgMyoA as a druggable target in infections with T. gondii. Since TgMyoA is essential for virulence, conserved in apicomplexan parasites, and distinctly different from the myosins found in humans, pharmacological inhibition of MyoA offers a promising new approach to treating the devastating diseases caused by T. gondii and other apicomplexan parasites.
Collapse
Affiliation(s)
- Anne Kelsen
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Robyn S. Kent
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Anne K. Snyder
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Eddie Wehri
- Center for Emerging and Neglected Diseases, University of California Berkeley, California, United States of America
| | - Stephen J. Bishop
- School of Chemistry and Biomedical Sciences Research Complex, University of St. Andrews and EaStCHEM, St Andrews, Fife, Scotland, United Kingdom
| | - Rachel V. Stadler
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Cameron Powell
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Bruno Martorelli di Genova
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Pramod K. Rompikuntal
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Martin J. Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - David M. Warshaw
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Nicholas J. Westwood
- School of Chemistry and Biomedical Sciences Research Complex, University of St. Andrews and EaStCHEM, St Andrews, Fife, Scotland, United Kingdom
| | - Julia Schaletzky
- Center for Emerging and Neglected Diseases, University of California Berkeley, California, United States of America
| | - Gary E. Ward
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| |
Collapse
|
9
|
Imlay LS, Lawong AK, Gahalawat S, Kumar A, Xing C, Mittal N, Wittlin S, Churchyard A, Niederstrasser H, Crespo-Fernandez B, Posner BA, Gamo FJ, Baum J, Winzeler EA, LALEU B, Ready JM, Phillips MA. Fast-Killing Tyrosine Amide (( S)-SW228703) with Blood- and Liver-Stage Antimalarial Activity Associated with the Cyclic Amine Resistance Locus ( PfCARL). ACS Infect Dis 2023; 9:527-539. [PMID: 36763526 PMCID: PMC10053980 DOI: 10.1021/acsinfecdis.2c00527] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Current malaria treatments are threatened by drug resistance, and new drugs are urgently needed. In a phenotypic screen for new antimalarials, we identified (S)-SW228703 ((S)-SW703), a tyrosine amide with asexual blood and liver stage activity and a fast-killing profile. Resistance to (S)-SW703 is associated with mutations in the Plasmodium falciparum cyclic amine resistance locus (PfCARL) and P. falciparum acetyl CoA transporter (PfACT), similarly to several other compounds that share features such as fast activity and liver-stage activity. Compounds with these resistance mechanisms are thought to act in the ER, though their targets are unknown. The tyramine of (S)-SW703 is shared with some reported PfCARL-associated compounds; however, we observed that strict S-stereochemistry was required for the activity of (S)-SW703, suggesting differences in the mechanism of action or binding mode. (S)-SW703 provides a new chemical series with broad activity for multiple life-cycle stages and a fast-killing mechanism of action, available for lead optimization to generate new treatments for malaria.
Collapse
Affiliation(s)
- Leah S. Imlay
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Aloysus K. Lawong
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Suraksha Gahalawat
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Ashwani Kumar
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Chao Xing
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Nimisha Mittal
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland
- University of Basel, 4002, Basel, Switzerland
| | - Alisje Churchyard
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Hanspeter Niederstrasser
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - Bruce A. Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - Jake Baum
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
- School of Biomedical Sciences, University of New South Wales, Kensington, NSW, Australia
| | - Elizabeth A. Winzeler
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA
| | - Benoît LALEU
- Medicines for Malaria Venture, 1215 Geneva 15, Switzerland
| | - Joseph M. Ready
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Margaret A. Phillips
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| |
Collapse
|
10
|
Istvan ES, Guerra F, Abraham M, Huang KS, Rocamora F, Zhao H, Xu L, Pasaje C, Kumpornsin K, Luth MR, Cui H, Yang T, Diaz SP, Gomez-Lorenzo MG, Qahash T, Mittal N, Ottilie S, Niles J, Lee MCS, Llinas M, Kato N, Okombo J, Fidock DA, Schimmel P, Gamo FJ, Goldberg DE, Winzeler EA. Cytoplasmic isoleucyl tRNA synthetase as an attractive multistage antimalarial drug target. Sci Transl Med 2023; 15:eadc9249. [PMID: 36888694 PMCID: PMC10286833 DOI: 10.1126/scitranslmed.adc9249] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 02/17/2023] [Indexed: 03/10/2023]
Abstract
Development of antimalarial compounds into clinical candidates remains costly and arduous without detailed knowledge of the target. As resistance increases and treatment options at various stages of disease are limited, it is critical to identify multistage drug targets that are readily interrogated in biochemical assays. Whole-genome sequencing of 18 parasite clones evolved using thienopyrimidine compounds with submicromolar, rapid-killing, pan-life cycle antiparasitic activity showed that all had acquired mutations in the P. falciparum cytoplasmic isoleucyl tRNA synthetase (cIRS). Engineering two of the mutations into drug-naïve parasites recapitulated the resistance phenotype, and parasites with conditional knockdowns of cIRS became hypersensitive to two thienopyrimidines. Purified recombinant P. vivax cIRS inhibition, cross-resistance, and biochemical assays indicated a noncompetitive, allosteric binding site that is distinct from that of known cIRS inhibitors mupirocin and reveromycin A. Our data show that Plasmodium cIRS is an important chemically and genetically validated target for next-generation medicines for malaria.
Collapse
Affiliation(s)
- Eva S. Istvan
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Francisco Guerra
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Matthew Abraham
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | - Frances Rocamora
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | - Lan Xu
- The Global Health Drug Discovery Institute, Tsinghua University 30 Shuangqing Rd, Haidian District, Beijing, China
| | - Charisse Pasaje
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Madeline R. Luth
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Haissi Cui
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tuo Yang
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Sara Palomo Diaz
- Global Health Medicines, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Spain
| | | | - Tarrick Qahash
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
| | - Nimisha Mittal
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Sabine Ottilie
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Jacquin Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Marcus C. S. Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
| | - Manuel Llinas
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Nobutaka Kato
- The Global Health Drug Discovery Institute, Tsinghua University 30 Shuangqing Rd, Haidian District, Beijing, China
| | - John Okombo
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York 10032, USA
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York 10032, USA
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York 10032, USA
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Elizabeth A. Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| |
Collapse
|
11
|
Branched chain amino acids catabolism as a source of new drug targets in pathogenic protists. Exp Parasitol 2023; 249:108499. [PMID: 36898495 DOI: 10.1016/j.exppara.2023.108499] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/02/2023] [Accepted: 03/05/2023] [Indexed: 03/11/2023]
Abstract
Leucine, isoleucine, and valine, collectively termed Branched Chain Amino Acids (BCAA), are hydrophobic amino acids (AAs) and are essential for most eukaryotes since in these organisms they cannot be biosynthesized and must be supplied by the diet. These AAs are structurally relevant for muscle cells and, of course, important for the protein synthesis process. The metabolism of BCAA and its participation in different biological processes in mammals have been relatively well described. However, for other organisms as pathogenic parasites, the literature is really scarce. Here we review the BCAA catabolism, compile evidence on their relevance for pathogenic eukaryotes with special emphasis on kinetoplastids and highlight unique aspects of this underrated pathway.
Collapse
|
12
|
Sharma VK, Chhibber-Goel J, Yogavel M, Sharma A. Structural characterization of glutamyl-tRNA synthetase (GluRS) from Plasmodium falciparum. Mol Biochem Parasitol 2023; 253:111530. [PMID: 36370911 DOI: 10.1016/j.molbiopara.2022.111530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 11/05/2022] [Accepted: 11/08/2022] [Indexed: 11/11/2022]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes in protein translation machinery that provide the charged tRNAs needed for protein synthesis. Over the past decades, aaRSs have been studied as anti-parasitic, anti-bacterial, and anti-fungal drug targets. This study focused on the cytoplasmic glutamyl-tRNA synthetase (GluRS) from Plasmodium falciparum, which belongs to class Ib in aaRSs. GluRS unlike most other aaRSs requires tRNA to activate its cognate amino acid substrate L-Glutamate (L-Glu), and fails to form an intermediate adenylate complex in the absence of tRNA. The crystal structures of the Apo, ATP, and ADP-bound forms of Plasmodium falciparum glutamyl-tRNA synthetase (PfGluRS) were solved at 2.1 Å, 2.2 Å, and 2.8 Å respectively. The structural comparison of the Apo- and ATP-bound holo-forms of PfGluRS showed considerable conformational changes in the loop regions around the ATP-binding pocket of the enzyme. Biophysical characterization of the PfGluRS showed binding of the enzyme substrates L-Gluand ATP.. The sequence and structural conservation were evident across GluRS compared to other species. The structural dissection of the PfGluRS gives insight into the critical residues involved in the binding of ATP substrate, which can be harvested to develop new antimalarial drugs.
Collapse
Affiliation(s)
- Vivek Kumar Sharma
- Molecular Medicine - Structural Parasitology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Jyoti Chhibber-Goel
- Molecular Medicine - Structural Parasitology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Manickam Yogavel
- Molecular Medicine - Structural Parasitology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Amit Sharma
- Molecular Medicine - Structural Parasitology, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.
| |
Collapse
|
13
|
Gill J, Sharma A. Exploration of aminoacyl-tRNA synthetases from eukaryotic parasites for drug development. J Biol Chem 2022; 299:102860. [PMID: 36596362 PMCID: PMC9978631 DOI: 10.1016/j.jbc.2022.102860] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 01/01/2023] Open
Abstract
Parasitic diseases result in considerable human morbidity and mortality. The continuous emergence and spread of new drug-resistant parasite strains is an obstacle to controlling and eliminating many parasitic diseases. Aminoacyl-tRNA synthetases (aaRSs) are ubiquitous enzymes essential for protein synthesis. The design and development of diverse small molecule, drug-like inhibitors against parasite-encoded and expressed aaRSs have validated this enzyme family as druggable. In this work, we have compiled the progress to date towards establishing the druggability of aaRSs in terms of their biochemical characterization, validation as targets, inhibitor development, and structural interpretation from parasites responsible for malaria (Plasmodium), lymphatic filariasis (Brugia,Wuchereria bancrofti), giardiasis (Giardia), toxoplasmosis (Toxoplasma gondii), leishmaniasis (Leishmania), cryptosporidiosis (Cryptosporidium), and trypanosomiasis (Trypanosoma). This work thus provides a robust framework for the systematic dissection of aaRSs from these pathogens and will facilitate the cross-usage of potential inhibitors to jump-start anti-parasite drug development.
Collapse
Affiliation(s)
- Jasmita Gill
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Amit Sharma
- ICMR-National Institute of Malaria Research, New Delhi, India; Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
| |
Collapse
|
14
|
Robbins CE, Patel B, Sawyer DL, Wilkinson B, Kennedy BK, McCormick MA. Cytosolic and mitochondrial tRNA synthetase inhibitors increase lifespan in a GCN4/atf-4-dependent manner. iScience 2022; 25:105410. [DOI: 10.1016/j.isci.2022.105410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 09/12/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
|
15
|
Lysyl-tRNA synthetase, a target for urgently needed M. tuberculosis drugs. Nat Commun 2022; 13:5992. [PMID: 36220877 PMCID: PMC9552147 DOI: 10.1038/s41467-022-33736-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 09/30/2022] [Indexed: 11/08/2022] Open
Abstract
Tuberculosis is a major global cause of both mortality and financial burden mainly in low and middle-income countries. Given the significant and ongoing rise of drug-resistant strains of Mycobacterium tuberculosis within the clinical setting, there is an urgent need for the development of new, safe and effective treatments. Here the development of a drug-like series based on a fused dihydropyrrolidino-pyrimidine scaffold is described. The series has been developed against M. tuberculosis lysyl-tRNA synthetase (LysRS) and cellular studies support this mechanism of action. DDD02049209, the lead compound, is efficacious in mouse models of acute and chronic tuberculosis and has suitable physicochemical, pharmacokinetic properties and an in vitro safety profile that supports further development. Importantly, preliminary analysis using clinical resistant strains shows no pre-existing clinical resistance towards this scaffold.
Collapse
|
16
|
Kushwaha V, Capalash N. Aminoacyl-tRNA synthetase (AARS) as an attractive drug target in neglected tropical trypanosomatid diseases-Leishmaniasis, Human African Trypanosomiasis and Chagas disease. Mol Biochem Parasitol 2022; 251:111510. [PMID: 35988745 DOI: 10.1016/j.molbiopara.2022.111510] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/09/2022] [Accepted: 08/16/2022] [Indexed: 10/15/2022]
Abstract
TriTryp diseases (Leishmaniasis, Human African Trypanosomiasis (HAT), and Chagas disease) are devastating parasitic neglected tropical diseases (NTDs) that affect billions of people in developing countries, cause high mortality in humans, and impose a large socio-economic burden. The current treatment options against tritryp diseases are suboptimal and challenging due to the emergence of resistance against available tritryp drugs. Hence, designing and developing effective anti-tritryp drugs with novel targets are required. Aminoacyl-tRNA synthetases (AARSs) involved in specific aminoacylation of transfer RNAs (tRNAs), interrupt protein synthesis through inhibitors, and retard the parasite growth. AaRSs have long been studied as therapeutic targets in bacteria, and three aaRS inhibitors, mupirocin (against IleRS), tavaborole AN2690 (against LeuRS), and halofuginone (against ProRS), are already in clinical practice. The structural differences between tritryp and human aaRSs and the presence of unique sequences (N-terminal domain/C-terminal domain/catalytic domain) make them potential target for developing selective inhibitors. Drugs based on a single aaRS target developed by high-throughput screening (HTS) are less effective due to the emergence of resistance. However, designing multi-targeted drugs may be a better strategy for resistance development. In this perspective, we discuss the characteristics of tritryp aaRSs, sequence conservation in their orthologs and their peculiarities, recent advancements towards the single-target and multi-target aaRS inhibitors developed through rational design.
Collapse
Affiliation(s)
- Vikas Kushwaha
- Department of Biotechnology, Panjab University, Sector-25, South Campus, Chandigarh 160025, India.
| | - Neena Capalash
- Department of Biotechnology, Panjab University, Sector-25, South Campus, Chandigarh 160025, India.
| |
Collapse
|
17
|
Nair S, Li X, Arya GA, McDew-White M, Ferrari M, Anderson T. Nutrient Limitation Magnifies Fitness Costs of Antimalarial Drug Resistance Mutations. Antimicrob Agents Chemother 2022; 66:e0152921. [PMID: 35465723 PMCID: PMC9112896 DOI: 10.1128/aac.01529-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 02/22/2022] [Indexed: 12/15/2022] Open
Abstract
Drug resistance mutations tend to disrupt key physiological processes and frequently carry fitness costs, which are a central determinant of the rate of spread of these mutations in natural populations. Head-to-head competition assays provide a standard approach to measuring fitness for malaria parasites. These assays typically use a standardized culture medium containing RPMI 1640, which has a 1.4- to 5.5-fold higher concentration of amino acids than human blood. In this rich medium, we predict that fitness costs will be underestimated because resource competition is weak. We tested this prediction using an artemisinin-sensitive parasite edited to contain kelch-C580Y or R561H mutations conferring resistance to artemisinin or synonymous control mutations. We examined the impact of these single amino acid mutations on fitness, using replicated head-to-head competition experiments conducted in media containing (i) normal RPMI, (ii) modified RPMI with reduced amino acid concentration, (iii) RPMI containing only isoleucine, or (iv) 3-fold diluted RPMI. We found a significant 1.3- to 1.4-fold increase in fitness costs measured in modified and isoleucine-only media relative to normal media, while fitness costs were 2.5-fold higher in diluted media. We conclude that fitness costs are strongly affected by media composition and will be significantly underestimated in normal RPMI. Several components differed between media, including pABA and sodium bicarbonate concentrations, so we cannot directly determine which is responsible. Elevated fitness costs in nature will limit spread of artemisinin (ART) resistance but will also promote evolution of compensatory mutations that restore fitness and can be exploited to maximize selection in laboratory experiments.
Collapse
Affiliation(s)
- Shalini Nair
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Xue Li
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Grace A. Arya
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Marina McDew-White
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Marco Ferrari
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Tim Anderson
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| |
Collapse
|
18
|
Hajialiani F, Shahbazzadeh D, Maleki F, Elmi T, Tabatabaie F, Zamani Z. The Metabolomic Profiles of Sera of Mice Infected with Plasmodium berghei and Treated by Effective Fraction of Naja naja oxiana Using 1H Nuclear Magnetic Resonance Spectroscopy. Acta Parasitol 2021; 66:1517-1527. [PMID: 34357584 DOI: 10.1007/s11686-021-00456-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 07/08/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND The use of venom fractions from the Iranian cobra could be useful adjunct treatments of malaria with chloroquine. A metabolomic investigation with 1HNMR spectroscopy was conducted on an effective fraction tested earlier using Plasmodium berghei as an experimental murine model. PURPOSE We sought to ascertain both safety and anti-parasitic effects of experimental therapies. METHODS After purification of the venom fractions, 25 mice were infected, then treated for 4 days with 0.2 ml of 5 mg/kg, 2.5 mg/kg and 1 mg/kg of the effective fraction, chloroquine, and a drug vehicle. An ED50 was obtained using Giemsa staining and real-time PCR analysis. The toxicity tests inspecting both liver and kidney tissues were performed. RESULTS A clear inhibitory effect on parasitaemia was observed (with 75% inhibition with 5 mg/kg and 50% reduction when 2.5 mg/kg dosage used). ED50 obtained 2.5 mg/kg. The metabolomics were identified as differentiation of aminoacyl-t-RNA biosynthesis, valine, leucine, isoleucine biosynthesis and degradation pathways were observed. CONCLUSION Upon therapeutic effects of cobra venom fraction, further optimization of dose-dependent response of pharmacokinetics would be worthwhile for further exploration in adjunct experimental venom therapies.
Collapse
|
19
|
Okeke CJ, Musyoka TM, Sheik Amamuddy O, Barozi V, Tastan Bishop Ö. Allosteric pockets and dynamic residue network hubs of falcipain 2 in mutations including those linked to artemisinin resistance. Comput Struct Biotechnol J 2021; 19:5647-5666. [PMID: 34745456 PMCID: PMC8545671 DOI: 10.1016/j.csbj.2021.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 09/30/2021] [Accepted: 10/03/2021] [Indexed: 10/29/2022] Open
Abstract
Continually emerging resistant strains of malarial parasites to current drugs present challenges. Understanding the underlying resistance mechanisms, especially those linked to allostery is, thus, highly crucial for drug design. This forms the main concern of the paper through a case study of falcipain 2 (FP-2) and its mutations, some of which are linked to artemisinin (ART) drug resistance. Here, we applied a variety of in silico approaches and tools that we developed recently, together with existing computational tools. This included novel essential dynamics and dynamic residue network (DRN) analysis algorithms. We identified six pockets demonstrating dynamic differences in the presence of some mutations. We observed striking allosteric effects in two mutant proteins. In the presence of M245I, a cryptic pocket was detected via a unique mechanism in which Pocket 2 fused with Pocket 6. In the presence of the A353T mutation, which is located at Pocket 2, the pocket became the most rigid among all protein systems analyzed. Pocket 6 was also highly stable in all cases, except in the presence of M245I mutation. The effect of ART linked mutations was more subtle, and the changes were at residue level. Importantly, we identified an allosteric communication path formed by four unique averaged BC hubs going from the mutated residue to the catalytic site and passing through the interface of three identified pockets. Collectively, we established and demonstrated that we have robust tools and a pipeline that can be applicable to the analysis of mutations.
Collapse
Affiliation(s)
| | | | - Olivier Sheik Amamuddy
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140, South Africa
| | - Victor Barozi
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140, South Africa
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda 6140, South Africa
| |
Collapse
|
20
|
Chhibber-Goel J, Yogavel M, Sharma A. Structural analyses of the malaria parasite aminoacyl-tRNA synthetases provide new avenues for antimalarial drug discovery. Protein Sci 2021; 30:1793-1803. [PMID: 34184352 DOI: 10.1002/pro.4148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/12/2021] [Accepted: 06/22/2021] [Indexed: 11/10/2022]
Abstract
Malaria is a parasitic illness caused by the genus Plasmodium from the apicomplexan phylum. Five plasmodial species of P. falciparum (Pf), P. knowlesi, P. malariae, P. ovale, and P. vivax (Pv) are responsible for causing malaria in humans. According to the World Malaria Report 2020, there were 229 million cases and ~ 0.04 million deaths of which 67% were in children below 5 years of age. While more than 3 billion people are at risk of malaria infection globally, antimalarial drugs are their only option for treatment. Antimalarial drug resistance keeps arising periodically and thus threatens the main line of malaria treatment, emphasizing the need to find new alternatives. The availability of whole genomes of P. falciparum and P. vivax has allowed targeting their unexplored plasmodial enzymes for inhibitor development with a focus on multistage targets that are crucial for parasite viability in both the blood and liver stages. Over the past decades, aminoacyl-tRNA synthetases (aaRSs) have been explored as anti-bacterial and anti-fungal drug targets, and more recently (since 2009) aaRSs are also the focus of antimalarial drug targeting. Here, we dissect the structure-based knowledge of the most advanced three aaRSs-lysyl- (KRS), prolyl- (PRS), and phenylalanyl- (FRS) synthetases in terms of development of antimalarial drugs. These examples showcase the promising potential of this family of enzymes to provide druggable targets that stall protein synthesis upon inhibition and thereby kill malaria parasites selectively.
Collapse
Affiliation(s)
- Jyoti Chhibber-Goel
- Structural Parasitology Group, Molecular Medicine, International Center for Genetic Engineering and Biotechnology, New Delhi, India
| | - Manickam Yogavel
- Structural Parasitology Group, Molecular Medicine, International Center for Genetic Engineering and Biotechnology, New Delhi, India
| | - Amit Sharma
- Structural Parasitology Group, Molecular Medicine, International Center for Genetic Engineering and Biotechnology, New Delhi, India.,ICMR-National Institute of Malaria Research, New Delhi, India
| |
Collapse
|
21
|
Yang T, Ottilie S, Istvan ES, Godinez-Macias KP, Lukens AK, Baragaña B, Campo B, Walpole C, Niles JC, Chibale K, Dechering KJ, Llinás M, Lee MCS, Kato N, Wyllie S, McNamara CW, Gamo FJ, Burrows J, Fidock DA, Goldberg DE, Gilbert IH, Wirth DF, Winzeler EA. MalDA, Accelerating Malaria Drug Discovery. Trends Parasitol 2021; 37:493-507. [PMID: 33648890 PMCID: PMC8261838 DOI: 10.1016/j.pt.2021.01.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 12/24/2022]
Abstract
The Malaria Drug Accelerator (MalDA) is a consortium of 15 leading scientific laboratories. The aim of MalDA is to improve and accelerate the early antimalarial drug discovery process by identifying new, essential, druggable targets. In addition, it seeks to produce early lead inhibitors that may be advanced into drug candidates suitable for preclinical development and subsequent clinical testing in humans. By sharing resources, including expertise, knowledge, materials, and reagents, the consortium strives to eliminate the structural barriers often encountered in the drug discovery process. Here we discuss the mission of the consortium and its scientific achievements, including the identification of new chemically and biologically validated targets, as well as future scientific directions.
Collapse
Affiliation(s)
- Tuo Yang
- Department of Pediatrics, School of Medicine, University of California, San Diego (UCSD), La Jolla, CA 92093, USA
| | - Sabine Ottilie
- Department of Pediatrics, School of Medicine, University of California, San Diego (UCSD), La Jolla, CA 92093, USA
| | - Eva S Istvan
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO 63130, USA; Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63130, USA
| | - Karla P Godinez-Macias
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego (UCSD), La Jolla, CA 92093, USA
| | - Amanda K Lukens
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Beatriz Baragaña
- Wellcome Center for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee DD1 5EH, UK
| | - Brice Campo
- Medicines for Malaria Venture, 1215 Geneva 15, Switzerland
| | - Chris Walpole
- Structural Genomics Consortium, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology (MIT), Building 56-341, 77 Massachusetts Avenue, Cambridge MA 02139-4307, USA
| | - Kelly Chibale
- Drug Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | | | - Manuel Llinás
- Department of Biochemistry and Molecular Biology and Department of Chemistry, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA 16082, USA
| | - Marcus C S Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Nobutaka Kato
- Global Health Drug Discovery Institute, Zhongguancun Dongsheng International Science Park, 1 North Yongtaizhuang Road, Beijing 100192, China
| | - Susan Wyllie
- Wellcome Center for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee DD1 5EH, UK
| | - Case W McNamara
- Calibr, a division of The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Francisco Javier Gamo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Jeremy Burrows
- Medicines for Malaria Venture, 1215 Geneva 15, Switzerland
| | - David A Fidock
- Department of Microbiology and Immunology and Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Daniel E Goldberg
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO 63130, USA; Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63130, USA
| | - Ian H Gilbert
- Wellcome Center for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee DD1 5EH, UK
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Elizabeth A Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego (UCSD), La Jolla, CA 92093, USA.
| |
Collapse
|
22
|
Pereira PHS, Garcia CRS. Melatonin action in Plasmodium infection: Searching for molecules that modulate the asexual cycle as a strategy to impair the parasite cycle. J Pineal Res 2021; 70:e12700. [PMID: 33025644 PMCID: PMC7757246 DOI: 10.1111/jpi.12700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 02/06/2023]
Abstract
Half of the world's population lives in countries at risk of malaria infection, which results in approximately 450,000 deaths annually. Malaria parasites infect erythrocytes in a coordinated manner, with cycle durations in multiples of 24 hours, which reflects a behavior consistent with the host's circadian cycle. Interference in cycle coordination can help the immune system to naturally fight infection. Consequently, there is a search for new drugs that interfere with the cycle duration for combined treatment with conventional antimalarials. Melatonin appears to be a key host hormone responsible for regulating circadian behavior in the parasite cycle. In addition to host factors, there are still unknown factors intrinsic to the parasite that control the cycle duration. In this review, we present a series of reports of indole compounds and melatonin derivatives with antimalarial activity that were tested on several species of Plasmodium to evaluate the cytotoxicity to parasites and human cells, in addition to the ability to interfere with the development of the erythrocytic cycle. Most of the reported compounds had an IC50 value in the low micromolar range, without any toxicity to human cells. Triptosil, an indole derivative of melatonin, was able to inhibit the effect of melatonin in vitro without causing changes to the parasitemia. The wide variety of tested compounds indicates that it is possible to develop a compound capable of safely eliminating parasites from the host and interfering with the life cycle, which is promising for the development of new combined therapies against malaria.
Collapse
Affiliation(s)
- Pedro H. S. Pereira
- Department of Clinical and Toxicological AnalysesSchool of Pharmaceutical SciencesUniversity of São PauloSão PauloBrazil
| | - Celia R. S. Garcia
- Department of Clinical and Toxicological AnalysesSchool of Pharmaceutical SciencesUniversity of São PauloSão PauloBrazil
| |
Collapse
|
23
|
The Key Glycolytic Enzyme Phosphofructokinase Is Involved in Resistance to Antiplasmodial Glycosides. mBio 2020; 11:mBio.02842-20. [PMID: 33293381 PMCID: PMC7733947 DOI: 10.1128/mbio.02842-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Malaria, caused by Plasmodium parasites, continues to be a devastating global health issue, causing 405,000 deaths and 228 million cases in 2018. Understanding key metabolic processes in malaria parasites is critical to the development of new drugs to combat this major infectious disease. The Plasmodium glycolytic pathway is essential to the malaria parasite, providing energy for growth and replication and supplying important biomolecules for other essential Plasmodium anabolic pathways. Despite this overreliance on glycolysis, no current drugs target glycolysis, and there is a paucity of information on critical glycolysis targets. Our work addresses this unmet need, providing new mechanistic insights into this key pathway. Plasmodium parasites rely heavily on glycolysis for ATP production and for precursors for essential anabolic pathways, such as the methylerythritol phosphate (MEP) pathway. Here, we show that mutations in the Plasmodium falciparum glycolytic enzyme, phosphofructokinase (PfPFK9), are associated with in vitro resistance to a primary sulfonamide glycoside (PS-3). Flux through the upper glycolysis pathway was significantly reduced in PS-3-resistant parasites, which was associated with reduced ATP levels but increased flux into the pentose phosphate pathway. PS-3 may directly or indirectly target enzymes in these pathways, as PS-3-treated parasites had elevated levels of glycolytic and tricarboxylic acid (TCA) cycle intermediates. PS-3 resistance also led to reduced MEP pathway intermediates, and PS-3-resistant parasites were hypersensitive to the MEP pathway inhibitor, fosmidomycin. Overall, this study suggests that PS-3 disrupts core pathways in central carbon metabolism, which is compensated for by mutations in PfPFK9, highlighting a novel metabolic drug resistance mechanism in P. falciparum.
Collapse
|
24
|
Abstract
Aminoacyl-tRNA synthetases (AARSs) have been considered very attractive drug-targets for decades. This interest probably emerged with the identification of differences in AARSs between prokaryotic and eukaryotic species, which provided a rationale for the development of antimicrobials targeting bacterial AARSs with minimal effect on the homologous human AARSs. Today we know that AARSs are not only attractive, but also valid drug targets as they are housekeeping proteins that: (i) play a fundamental role in protein translation by charging the corresponding amino acid to its cognate tRNA and preventing mistranslation mistakes [1], a critical process during fast growing conditions of microbes; and (ii) present significant differences between microbes and humans that can be used for drug development [2]. Together with the vast amount of available data on both pathogenic and mammalian AARSs, it is expected that, in the future, the numerous reported inhibitors of AARSs will provide the basis to develop new therapeutics for the treatment of human diseases. In this chapter, a detailed summary on the state-of-the-art in drug discovery and drug development for each aminoacyl-tRNA synthetase will be presented.
Collapse
Affiliation(s)
- Maria Lukarska
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Drug Targets in Human Diseases, INSERM U1209, CNRS UMR 5309, University Grenoble Alpes, Grenoble, France
| | - Andrés Palencia
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Drug Targets in Human Diseases, INSERM U1209, CNRS UMR 5309, University Grenoble Alpes, Grenoble, France.
| |
Collapse
|
25
|
Dziekan JM, Wirjanata G, Dai L, Go KD, Yu H, Lim YT, Chen L, Wang LC, Puspita B, Prabhu N, Sobota RM, Nordlund P, Bozdech Z. Cellular thermal shift assay for the identification of drug-target interactions in the Plasmodium falciparum proteome. Nat Protoc 2020; 15:1881-1921. [PMID: 32341577 DOI: 10.1038/s41596-020-0310-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/13/2020] [Indexed: 02/06/2023]
Abstract
Despite decades of research, little is known about the cellular targets and the mode of action of the vast majority of antimalarial drugs. We recently demonstrated that the cellular thermal shift assay (CETSA) protocol in its two variants: the melt curve and the isothermal dose-response, represents a comprehensive strategy for the identification of antimalarial drug targets. CETSA enables proteome-wide target screening for unmodified antimalarial compounds with undetermined mechanisms of action, providing quantitative evidence about direct drug-protein interactions. The experimental workflow involves treatment of P. falciparum-infected erythrocytes with a compound of interest, heat exposure to denature proteins, soluble protein isolation, enzymatic digestion, peptide labeling with tandem mass tags, offline fractionation, and liquid chromatography-tandem mass spectrometry analysis. Methodological optimizations necessary for the analysis of this intracellular parasite are discussed, including enrichment of parasitized cells and hemoglobin depletion strategies to overcome high hemoglobin abundance in the host red blood cells. We outline an effective data processing workflow using the mineCETSA R package, which enables prioritization of drug-target candidates for follow-up studies. The entire protocol can be completed within 2 weeks.
Collapse
Affiliation(s)
- Jerzy Michal Dziekan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Grennady Wirjanata
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Lingyun Dai
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,The Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen People's Hospital, Shenzhen, China
| | - Ka Diam Go
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Han Yu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yan Ting Lim
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Liyan Chen
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Loo Chien Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Brenda Puspita
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Nayana Prabhu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Radoslaw M Sobota
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore. .,Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
| | - Pär Nordlund
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore. .,Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore. .,Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| |
Collapse
|
26
|
Gu C, Mao X, Chen D, Yu B, Yang Q. Isoleucine Plays an Important Role for Maintaining Immune Function. Curr Protein Pept Sci 2019; 20:644-651. [PMID: 30843485 DOI: 10.2174/1389203720666190305163135] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 12/30/2018] [Accepted: 01/10/2019] [Indexed: 12/16/2022]
Abstract
Branched chain amino acids are the essential nutrients for humans and many animals. As functional amino acids, they play important roles in physiological functions, including immune functions. Isoleucine, as one of the branched chain amino acids, is also critical in physiological functions of the whole body, such as growth, immunity, protein metabolism, fatty acid metabolism and glucose transportation. Isoleucine can improve the immune system, including immune organs, cells and reactive substances. Recent studies have also shown that isoleucine may induce the expression of host defense peptides (i.e., β-defensins) that can regulate host innate and adaptive immunity. In addition, isoleucine administration can restore the effect of some pathogens on the health of humans and animals via increasing the expression of β-defensins. Therefore, the present review will emphatically discuss the effect of isoleucine on immunity while summarizing the relationship between branched chain amino acids and immune functions.
Collapse
Affiliation(s)
- Changsong Gu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease- Resistance Nutrition, Chinese Ministry of Education, Chengdu, China
| | - Xiangbing Mao
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease- Resistance Nutrition, Chinese Ministry of Education, Chengdu, China
| | - Daiwen Chen
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease- Resistance Nutrition, Chinese Ministry of Education, Chengdu, China
| | - Bing Yu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease- Resistance Nutrition, Chinese Ministry of Education, Chengdu, China
| | - Qing Yang
- Department of Animal Science, Oklahoma State University, Stillwater, Oklahoma, KS, United States
| |
Collapse
|
27
|
Musyoka T, Bishop ÖT. South African Abietane Diterpenoids and Their Analogs as Potential Antimalarials: Novel Insights from Hybrid Computational Approaches. Molecules 2019; 24:E4036. [PMID: 31703388 PMCID: PMC6891524 DOI: 10.3390/molecules24224036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/28/2019] [Accepted: 10/31/2019] [Indexed: 12/31/2022] Open
Abstract
The hemoglobin degradation process in Plasmodium parasites is vital for nutrient acquisition required for their growth and proliferation. In P. falciparum, falcipains (FP-2 and FP-3) are the major hemoglobinases, and remain attractive antimalarial drug targets. Other Plasmodium species also possess highly homologous proteins to FP-2 and FP-3. Although several inhibitors have been designed against these proteins, none has been commercialized due to associated toxicity on human cathepsins (Cat-K, Cat-L and Cat-S). Despite the two enzyme groups sharing a common structural fold and catalytic mechanism, distinct active site variations have been identified, and can be exploited for drug development. Here, we utilize in silico approaches to screen 628 compounds from the South African natural sources to identify potential hits that can selectively inhibit the plasmodial proteases. Using docking studies, seven abietane diterpenoids, binding strongly to the plasmodial proteases, and three additional analogs from PubChem were identified. Important residues involved in ligand stabilization were identified for all potential hits through binding pose analysis and their energetic contribution determined by binding free energy calculations. The identified compounds present important scaffolds that could be further developed as plasmodial protease inhibitors. Previous laboratory assays showed the effect of the seven diterpenoids as antimalarials. Here, for the first time, we demonstrate that their possible mechanism of action could be by interacting with falcipains and their plasmodial homologs. Dynamic residue network (DRN) analysis on the plasmodial proteases identified functionally important residues, including a region with high betweenness centrality, which had previously been proposed as a potential allosteric site in FP-2.
Collapse
Affiliation(s)
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa;
| |
Collapse
|
28
|
Martin RE. The transportome of the malaria parasite. Biol Rev Camb Philos Soc 2019; 95:305-332. [PMID: 31701663 DOI: 10.1111/brv.12565] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 12/15/2022]
Abstract
Membrane transport proteins, also known as transporters, control the movement of ions, nutrients, metabolites, and waste products across the membranes of a cell and are central to its biology. Proteins of this type also serve as drug targets and are key players in the phenomenon of drug resistance. The malaria parasite has a relatively reduced transportome, with only approximately 2.5% of its genes encoding transporters. Even so, assigning functions and physiological roles to these proteins, and ascertaining their contributions to drug action and drug resistance, has been very challenging. This review presents a detailed critique and synthesis of the disruption phenotypes, protein subcellular localisations, protein functions (observed or predicted), and links to antimalarial drug resistance for each of the parasite's transporter genes. The breadth and depth of the gene disruption data are particularly impressive, with at least one phenotype determined in the parasite's asexual blood stage for each transporter gene, and multiple phenotypes available for 76% of the genes. Analysis of the curated data set revealed there to be relatively little redundancy in the Plasmodium transportome; almost two-thirds of the parasite's transporter genes are essential or required for normal growth in the asexual blood stage of the parasite, and this proportion increased to 78% when the disruption phenotypes available for the other parasite life stages were included in the analysis. These observations, together with the finding that 22% of the transportome is implicated in the parasite's resistance to existing antimalarials and/or drugs within the development pipeline, indicate that transporters are likely to serve, or are already serving, as drug targets. Integration of the different biological and bioinformatic data sets also enabled the selection of candidates for transport processes known to be essential for parasite survival, but for which the underlying proteins have thus far remained undiscovered. These include potential transporters of pantothenate, isoleucine, or isopentenyl diphosphate, as well as putative anion-selective channels that may serve as the pore component of the parasite's 'new permeation pathways'. Other novel insights into the parasite's biology included the identification of transporters for the potential development of antimalarial treatments, transmission-blocking drugs, prophylactics, and genetically attenuated vaccines. The syntheses presented herein set a foundation for elucidating the functions and physiological roles of key members of the Plasmodium transportome and, ultimately, to explore and realise their potential as therapeutic targets.
Collapse
Affiliation(s)
- Rowena E Martin
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| |
Collapse
|
29
|
Targeting the apicoplast in malaria. Biochem Soc Trans 2019; 47:973-983. [PMID: 31383817 DOI: 10.1042/bst20170563] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 05/22/2019] [Accepted: 06/10/2019] [Indexed: 12/25/2022]
Abstract
Malaria continues to be one of the leading causes of human mortality in the world, and the therapies available are insufficient for eradication. Severe malaria is caused by the apicomplexan parasite Plasmodium falciparum Apicomplexan parasites, including the Plasmodium spp., are descendants of photosynthetic algae, and therefore they possess an essential plastid organelle, named the apicoplast. Since humans and animals have no plastids, the apicoplast is an attractive target for drug development. Indeed, after its discovery, the apicoplast was found to host the target pathways of some known antimalarial drugs, which motivated efforts for further research into its biological functions and biogenesis. Initially, many apicoplast inhibitions were found to result in 'delayed death', whereby parasite killing is seen only at the end of one invasion-egress cycle. This slow action is not in line with the current standard for antimalarials, which seeded scepticism about the potential of compounds targeting apicoplast functions as good candidates for drug development. Intriguingly, recent evidence of apicoplast inhibitors causing rapid killing could put this organelle back in the spotlight. We provide an overview of drugs known to inhibit apicoplast pathways, alongside recent findings in apicoplast biology that may provide new avenues for drug development.
Collapse
|
30
|
Zirin J, Ni X, Sack LM, Yang-Zhou D, Hu Y, Brathwaite R, Bulyk ML, Elledge SJ, Perrimon N. Interspecies analysis of MYC targets identifies tRNA synthetases as mediators of growth and survival in MYC-overexpressing cells. Proc Natl Acad Sci U S A 2019; 116:14614-14619. [PMID: 31262815 PMCID: PMC6642371 DOI: 10.1073/pnas.1821863116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Aberrant MYC oncogene activation is one of the most prevalent characteristics of cancer. By overlapping datasets of Drosophila genes that are insulin-responsive and also regulate nucleolus size, we enriched for Myc target genes required for cellular biosynthesis. Among these, we identified the aminoacyl tRNA synthetases (aaRSs) as essential mediators of Myc growth control in Drosophila and found that their pharmacologic inhibition is sufficient to kill MYC-overexpressing human cells, indicating that aaRS inhibitors might be used to selectively target MYC-driven cancers. We suggest a general principle in which oncogenic increases in cellular biosynthesis sensitize cells to disruption of protein homeostasis.
Collapse
Affiliation(s)
- Jonathan Zirin
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Xiaochun Ni
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Laura M Sack
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | | | - Yanhui Hu
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | | | - Martha L Bulyk
- Department of Genetics, Harvard Medical School, Boston, MA 02115
- Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115
| | - Stephen J Elledge
- Department of Genetics, Harvard Medical School, Boston, MA 02115
- Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, MA 02115;
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115
| |
Collapse
|
31
|
Musyoka TM, Njuguna JN, Tastan Bishop Ö. Comparing sequence and structure of falcipains and human homologs at prodomain and catalytic active site for malarial peptide based inhibitor design. Malar J 2019; 18:159. [PMID: 31053072 PMCID: PMC6500056 DOI: 10.1186/s12936-019-2790-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 04/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Falcipains are major cysteine proteases of Plasmodium falciparum involved in haemoglobin degradation and remain attractive anti-malarial drug targets. Several inhibitors against these proteases have been identified, yet none of them has been approved for malaria treatment. Other Plasmodium species also possess highly homologous proteins to falcipains. For selective therapeutic targeting, identification of sequence and structure differences with homologous human cathepsins is necessary. The substrate processing activity of these proteins is tightly controlled via a prodomain segment occluding the active site which is chopped under low pH conditions exposing the catalytic site. Current work characterizes these proteases to identify residues mediating the prodomain regulatory function for the design of peptide based anti-malarial inhibitors. METHODS Sequence and structure variations between prodomain regions of plasmodial proteins and human cathepsins were determined using in silico approaches. Additionally, evolutionary clustering of these proteins was evaluated using phylogenetic analysis. High quality partial zymogen protein structures were modelled using homology modelling and residue interaction analysis performed between the prodomain segment and mature domain to identify key interacting residues between these two domains. The resulting information was used to determine short peptide sequences which could mimic the inherent regulatory function of the prodomain regions. Through flexible docking, the binding affinity of proposed peptides on the proteins studied was evaluated. RESULTS Sequence, evolutionary and motif analyses showed important differences between plasmodial and human proteins. Residue interaction analysis identified important residues crucial for maintaining prodomain integrity across the different proteins as well as the pro-segment responsible for inhibitory mechanism. Binding affinity of suggested peptides was highly dependent on their residue composition and length. CONCLUSIONS Despite the conserved structural and catalytic mechanism between human cathepsins and plasmodial proteases, current work revealed significant differences between the two protein groups which may provide valuable information for selective anti-malarial inhibitor development. Part of this study aimed to design peptide inhibitors based on endogenous inhibitory portions of protease prodomains as a novel aspect. Even though peptide inhibitors may not be practical solutions to malaria at this stage, the approach followed and results offer a promising means to find new malarial inhibitors.
Collapse
Affiliation(s)
- Thommas Mutemi Musyoka
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa
| | - Joyce Njoki Njuguna
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa.
| |
Collapse
|
32
|
Francklyn CS, Mullen P. Progress and challenges in aminoacyl-tRNA synthetase-based therapeutics. J Biol Chem 2019; 294:5365-5385. [PMID: 30670594 DOI: 10.1074/jbc.rev118.002956] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are universal enzymes that catalyze the attachment of amino acids to the 3' ends of their cognate tRNAs. The resulting aminoacylated tRNAs are escorted to the ribosome where they enter protein synthesis. By specifically matching amino acids to defined anticodon sequences in tRNAs, ARSs are essential to the physical interpretation of the genetic code. In addition to their canonical role in protein synthesis, ARSs are also involved in RNA splicing, transcriptional regulation, translation, and other aspects of cellular homeostasis. Likewise, aminoacylated tRNAs serve as amino acid donors for biosynthetic processes distinct from protein synthesis, including lipid modification and antibiotic biosynthesis. Thanks to the wealth of details on ARS structures and functions and the growing appreciation of their additional roles regulating cellular homeostasis, opportunities for the development of clinically useful ARS inhibitors are emerging to manage microbial and parasite infections. Exploitation of these opportunities has been stimulated by the discovery of new inhibitor frameworks, the use of semi-synthetic approaches combining chemistry and genome engineering, and more powerful techniques for identifying leads from the screening of large chemical libraries. Here, we review the inhibition of ARSs by small molecules, including the various families of natural products, as well as inhibitors developed by either rational design or high-throughput screening as antibiotics and anti-parasitic therapeutics.
Collapse
Affiliation(s)
- Christopher S Francklyn
- From the Department of Biochemistry, College of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Patrick Mullen
- From the Department of Biochemistry, College of Medicine, University of Vermont, Burlington, Vermont 05405
| |
Collapse
|
33
|
Luth MR, Gupta P, Ottilie S, Winzeler EA. Using in Vitro Evolution and Whole Genome Analysis To Discover Next Generation Targets for Antimalarial Drug Discovery. ACS Infect Dis 2018; 4:301-314. [PMID: 29451780 PMCID: PMC5848146 DOI: 10.1021/acsinfecdis.7b00276] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
![]()
Although
many new anti-infectives have been discovered and developed solely
using phenotypic cellular screening and assay optimization, most researchers
recognize that structure-guided drug design is more practical and
less costly. In addition, a greater chemical space can be interrogated
with structure-guided drug design. The practicality of structure-guided
drug design has launched a search for the targets of compounds discovered
in phenotypic screens. One method that has been used extensively in
malaria parasites for target discovery and chemical validation is in vitro evolution and whole genome analysis (IVIEWGA).
Here, small molecules from phenotypic screens with demonstrated antiparasitic
activity are used in genome-based target discovery methods. In this
Review, we discuss the newest, most promising druggable targets discovered
or further validated by evolution-based methods, as well as some exceptions.
Collapse
Affiliation(s)
- Madeline R. Luth
- Division of Host Pathogen Systems and Therapeutics, Department of Pediatrics, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Purva Gupta
- Division of Host Pathogen Systems and Therapeutics, Department of Pediatrics, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Sabine Ottilie
- Division of Host Pathogen Systems and Therapeutics, Department of Pediatrics, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Elizabeth A. Winzeler
- Division of Host Pathogen Systems and Therapeutics, Department of Pediatrics, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Skaggs School of Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| |
Collapse
|
34
|
Manickam Y, Chaturvedi R, Babbar P, Malhotra N, Jain V, Sharma A. Drug targeting of one or more aminoacyl-tRNA synthetase in the malaria parasite Plasmodium falciparum. Drug Discov Today 2018; 23:1233-1240. [PMID: 29408369 DOI: 10.1016/j.drudis.2018.01.050] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/02/2018] [Accepted: 01/29/2018] [Indexed: 11/28/2022]
Abstract
Malaria remains a major infectious disease and, despite incidence reduction, it threatens resurgence in drug-resistant forms. Antimalarial drugs remain the mainstay of therapeutic options and hence there is a constant need to identify and validate new druggable targets. Plasmodium falciparum aminoacyl-tRNA synthetases (Pf-aaRSs) drive protein translation and are potent targets for development of next-generation antimalarials. Here, we detail advances made in structural-biology-based investigations in Pf-aaRSs and discuss their distribution of druggable pockets. This review establishes a platform for systematic experimental dissection of malarial parasite aaRSs as a new focus for sustained drug development efforts against malaria.
Collapse
Affiliation(s)
- Yogavel Manickam
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Rini Chaturvedi
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Palak Babbar
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Nipun Malhotra
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Vitul Jain
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India; Present address: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, The Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India.
| |
Collapse
|
35
|
Cowell AN, Istvan ES, Lukens AK, Gomez-Lorenzo MG, Vanaerschot M, Sakata-Kato T, Flannery EL, Magistrado P, Owen E, Abraham M, LaMonte G, Painter HJ, Williams RM, Franco V, Linares M, Arriaga I, Bopp S, Corey VC, Gnädig NF, Coburn-Flynn O, Reimer C, Gupta P, Murithi JM, Moura PA, Fuchs O, Sasaki E, Kim SW, Teng CH, Wang LT, Akidil A, Adjalley S, Willis PA, Siegel D, Tanaseichuk O, Zhong Y, Zhou Y, Llinás M, Ottilie S, Gamo FJ, Lee MCS, Goldberg DE, Fidock DA, Wirth DF, Winzeler EA. Mapping the malaria parasite druggable genome by using in vitro evolution and chemogenomics. Science 2018; 359:191-199. [PMID: 29326268 PMCID: PMC5925756 DOI: 10.1126/science.aan4472] [Citation(s) in RCA: 170] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 11/02/2017] [Indexed: 12/21/2022]
Abstract
Chemogenetic characterization through in vitro evolution combined with whole-genome analysis can identify antimalarial drug targets and drug-resistance genes. We performed a genome analysis of 262 Plasmodium falciparum parasites resistant to 37 diverse compounds. We found 159 gene amplifications and 148 nonsynonymous changes in 83 genes associated with drug-resistance acquisition, where gene amplifications contributed to one-third of resistance acquisition events. Beyond confirming previously identified multidrug-resistance mechanisms, we discovered hitherto unrecognized drug target-inhibitor pairs, including thymidylate synthase and a benzoquinazolinone, farnesyltransferase and a pyrimidinedione, and a dipeptidylpeptidase and an arylurea. This exploration of the P. falciparum resistome and druggable genome will likely guide drug discovery and structural biology efforts, while also advancing our understanding of resistance mechanisms available to the malaria parasite.
Collapse
Affiliation(s)
- Annie N Cowell
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Eva S Istvan
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Amanda K Lukens
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
- Infectious Disease Program, The Broad Institute, 415 Main Street, Cambridge, MA 02142, USA
| | - Maria G Gomez-Lorenzo
- Tres Cantos Medicines Development Campus, Malaria Discovery Performance Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Manu Vanaerschot
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Tomoyo Sakata-Kato
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Erika L Flannery
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Pamela Magistrado
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Edward Owen
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Matthew Abraham
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Gregory LaMonte
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Heather J Painter
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Roy M Williams
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Virginia Franco
- Tres Cantos Medicines Development Campus, Malaria Discovery Performance Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Maria Linares
- Tres Cantos Medicines Development Campus, Malaria Discovery Performance Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Ignacio Arriaga
- Tres Cantos Medicines Development Campus, Malaria Discovery Performance Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Selina Bopp
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Victoria C Corey
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Nina F Gnädig
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Olivia Coburn-Flynn
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Christin Reimer
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Purva Gupta
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - James M Murithi
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Pedro A Moura
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Olivia Fuchs
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Erika Sasaki
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Sang W Kim
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Christine H Teng
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Lawrence T Wang
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Aslı Akidil
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Sophie Adjalley
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Paul A Willis
- Medicines for Malaria Venture, Post Office Box 1826, 20 Route de Pre-Bois, 1215 Geneva 15, Switzerland
| | - Dionicio Siegel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UCSD, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Olga Tanaseichuk
- Genomics Institute of the Novartis Research Foundation, 10675 John J Hopkins Drive, San Diego, CA 92121, USA
| | - Yang Zhong
- Genomics Institute of the Novartis Research Foundation, 10675 John J Hopkins Drive, San Diego, CA 92121, USA
| | - Yingyao Zhou
- Genomics Institute of the Novartis Research Foundation, 10675 John J Hopkins Drive, San Diego, CA 92121, USA
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Sabine Ottilie
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Francisco-Javier Gamo
- Tres Cantos Medicines Development Campus, Malaria Discovery Performance Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Marcus C S Lee
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Daniel E Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
- Division of Infectious Diseases, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Dyann F Wirth
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
- Infectious Disease Program, The Broad Institute, 415 Main Street, Cambridge, MA 02142, USA
| | - Elizabeth A Winzeler
- School of Medicine, University of California San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA.
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UCSD, 9500 Gilman Drive, La Jolla, CA 92093, USA
| |
Collapse
|
36
|
Validation of Putative Apicoplast-Targeting Drugs Using a Chemical Supplementation Assay in Cultured Human Malaria Parasites. Antimicrob Agents Chemother 2017; 62:AAC.01161-17. [PMID: 29109165 DOI: 10.1128/aac.01161-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/18/2017] [Indexed: 11/20/2022] Open
Abstract
Malaria parasites contain a relict plastid, the apicoplast, which is considered an excellent drug target due to its bacterial-like ancestry. Numerous parasiticidals have been proposed to target the apicoplast, but few have had their actual targets substantiated. Isopentenyl pyrophosphate (IPP) production is the sole required function of the apicoplast in the blood stage of the parasite life cycle, and IPP supplementation rescues parasites from apicoplast-perturbing drugs. Hence, any drug that kills parasites when IPP is supplied in culture must have a nonapicoplast target. Here, we use IPP supplementation to discriminate whether 23 purported apicoplast-targeting drugs are on- or off-target. We demonstrate that a prokaryotic DNA replication inhibitor (ciprofloxacin), several prokaryotic translation inhibitors (chloramphenicol, doxycycline, tetracycline, clindamycin, azithromycin, erythromycin, and clarithromycin), a tRNA synthase inhibitor (mupirocin), and two IPP synthesis pathway inhibitors (fosmidomycin and FR900098) have apicoplast targets. Intriguingly, fosmidomycin and FR900098 leave the apicoplast intact, whereas the others eventually result in apicoplast loss. Actinonin, an inhibitor of bacterial posttranslational modification, does not produce a typical delayed-death response but is rescued with IPP, thereby confirming its apicoplast target. Parasites treated with putative apicoplast fatty acid pathway inhibitors could not be rescued, demonstrating that these drugs have their primary targets outside the apicoplast, which agrees with the dispensability of the apicoplast fatty acid synthesis pathways in the blood stage of malaria parasites. IPP supplementation provides a simple test of whether a compound has a target in the apicoplast and can be used to screen novel compounds for mode of action.
Collapse
|
37
|
Targeting Prolyl-tRNA Synthetase to Accelerate Drug Discovery against Malaria, Leishmaniasis, Toxoplasmosis, Cryptosporidiosis, and Coccidiosis. Structure 2017; 25:1495-1505.e6. [PMID: 28867614 DOI: 10.1016/j.str.2017.07.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 06/02/2017] [Accepted: 07/26/2017] [Indexed: 11/24/2022]
Abstract
Developing anti-parasitic lead compounds that act on key vulnerabilities are necessary for new anti-infectives. Malaria, leishmaniasis, toxoplasmosis, cryptosporidiosis and coccidiosis together kill >500,000 humans annually. Their causative parasites Plasmodium, Leishmania, Toxoplasma, Cryptosporidium and Eimeria display high conservation in many housekeeping genes, suggesting that these parasites can be attacked by targeting invariant essential proteins. Here, we describe selective and potent inhibition of prolyl-tRNA synthetases (PRSs) from the above parasites using a series of quinazolinone-scaffold compounds. Our PRS-drug co-crystal structures reveal remarkable active site plasticity that accommodates diversely substituted compounds, an enzymatic feature that can be leveraged for refining drug-like properties of quinazolinones on a per parasite basis. A compound we termed In-5 exhibited a unique double conformation, enhanced drug-like properties, and cleared malaria in mice. It thus represents a new lead for optimization. Collectively, our data offer insights into the structure-guided optimization of quinazolinone-based compounds for drug development against multiple human eukaryotic pathogens.
Collapse
|
38
|
Awasthi V, Chattopadhyay D, Das J. Potential Hemoglobin A/F role in clinical Malaria. Bioinformation 2017; 13:269-273. [PMID: 28959096 PMCID: PMC5609292 DOI: 10.6026/97320630013269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 08/18/2017] [Accepted: 08/19/2017] [Indexed: 11/24/2022] Open
Abstract
The Malarial parasite resides in the host RBC during its erythrocytic cycle. Plasmodium meets its entire nutritional requirement from RBC. It scavenges the hemoglobin of RBCs to meet its amino acid requirement. The host hemoglobin is made of different chains and it is dependent on age. Hemoglobin F (HbF), which has two-alpha and two gamma chain persists in children upto six years, and hemoglobin A (HbA) made of two alpha and two beta chains dominates. Therefore, it is of interest to compare the compositional features of HbA with HbF. Isoleucine is present in hemoglobin of children (gamma chain of HbF) while it is absent in adult hemoglobin (HbA). The presence of Isoleucine (I) makes HbF ideally suitable for the growth of parasite, as it does not have to depend upon the exogenous supply of the isoleucine, which might be responsible for making children more vulnerable to malaria as compared to adults.
Collapse
Affiliation(s)
- Vikky Awasthi
- Immunology Division, ICMR-National Institute of Malaria Research, Dwarka, New Delhi; Present Address: Regional Medical Research Centre, Belagavi, Nehru Nagar, National Highway No.4, Belagavi-590010, Karnataka, India
| | | | - Jyoti Das
- Immunology Division, ICMR-National Institute of Malaria Research, Dwarka, New Delhi; Present Address: Regional Medical Research Centre, Belagavi, Nehru Nagar, National Highway No.4, Belagavi-590010, Karnataka, India
| |
Collapse
|
39
|
Abstract
Malaria is caused in humans by five species of single-celled eukaryotic Plasmodium parasites (mainly Plasmodium falciparum and Plasmodium vivax) that are transmitted by the bite of Anopheles spp. mosquitoes. Malaria remains one of the most serious infectious diseases; it threatens nearly half of the world's population and led to hundreds of thousands of deaths in 2015, predominantly among children in Africa. Malaria is managed through a combination of vector control approaches (such as insecticide spraying and the use of insecticide-treated bed nets) and drugs for both treatment and prevention. The widespread use of artemisinin-based combination therapies has contributed to substantial declines in the number of malaria-related deaths; however, the emergence of drug resistance threatens to reverse this progress. Advances in our understanding of the underlying molecular basis of pathogenesis have fuelled the development of new diagnostics, drugs and insecticides. Several new combination therapies are in clinical development that have efficacy against drug-resistant parasites and the potential to be used in single-dose regimens to improve compliance. This ambitious programme to eliminate malaria also includes new approaches that could yield malaria vaccines or novel vector control strategies. However, despite these achievements, a well-coordinated global effort on multiple fronts is needed if malaria elimination is to be achieved.
Collapse
Affiliation(s)
- Margaret A Phillips
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, USA
| | | | | | | | - Wesley C Van Voorhis
- University of Washington, Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases, Seattle, Washington, USA
| | | |
Collapse
|
40
|
Sengupta A, Ghosh S, Das BK, Panda A, Tripathy R, Pied S, Ravindran B, Pathak S, Sharma S, Sonawat HM. Host metabolic responses to Plasmodium falciparum infections evaluated by 1H NMR metabolomics. MOLECULAR BIOSYSTEMS 2017; 12:3324-3332. [PMID: 27546486 DOI: 10.1039/c6mb00362a] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The human malarial parasite Plasmodium falciparum causes the most severe forms of malarial infections, which include cerebral malaria and various organ dysfunctions amongst adults in India. So far no dependable clinical descriptor is available that can distinguish cerebral malaria from other symptomatically similar diseases such as sepsis and encephalitis. This study aims at evaluating the differential metabolic features of plasma samples from P. falciparum patients with varying severities, and patients suffering from symptomatically similar diseases. 1H Nuclear Magnetic Resonance (NMR) based metabolic profiling of the plasma of the infected individuals and the control population was performed. The differences in the plasma profiles were evaluated through multivariate statistical analyses. The results suggest malaria-specific elevation of plasma lipoproteins. Such an increase was absent in control populations. In addition, cerebral malaria patients exhibited a decrease in plasma glycoproteins; such a reduction was not observed in malarial patients without cerebral symptoms. The data presented here indicates that the metabolism and/or transport of the plasma lipids is specifically perturbed by malarial infections. The differential perturbation of the plasma glycoprotein levels in cerebral malaria patients may have important implications in the diagnosis of cerebral malaria.
Collapse
Affiliation(s)
- Arjun Sengupta
- University of Pennsylvania, Systems Pharmacology and Translational Therapeutics, Philadelphia, Pennsylvania, USA
| | - Soumita Ghosh
- Tata Institute of Fundamental Research, Department of Chemical Sciences, Homi Bhabha Road, Mumbai, Maharashtra, India.
| | - Bidyut K Das
- SCB Medical College, Department of Medicine, Cuttack, Odhisa, India
| | - Abhinash Panda
- SCB Medical College, Department of Medicine, Cuttack, Odhisa, India
| | - Rina Tripathy
- SCB Medical College, Department of Biochemistry, Cuttack, Odisha, India
| | - Sylviane Pied
- Centre for Infection and Immunity of Lille, Centre for Infection and Immunity of Lille, Lille, Cedex, France
| | - B Ravindran
- Institute of Life Sciences, Bhubaneswar, Odisha 751023, India
| | - Sulabha Pathak
- TIFR, Department of Biological Sciences, Mumbai, Maharashtra, India
| | - Shobhona Sharma
- Tata Institute of Fundamental Research, Department of Chemical Sciences, Homi Bhabha Road, Mumbai, Maharashtra, India.
| | - Haripalsingh M Sonawat
- Tata Institute of Fundamental Research, Department of Chemical Sciences, Homi Bhabha Road, Mumbai, Maharashtra, India.
| |
Collapse
|
41
|
Ramakrishnan G, Chandra N, Srinivasan N. Exploring anti-malarial potential of FDA approved drugs: an in silico approach. Malar J 2017; 16:290. [PMID: 28720135 PMCID: PMC5516367 DOI: 10.1186/s12936-017-1937-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 07/13/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The critically important issue on emergence of drug-resistant malarial parasites is compounded by cross resistance, where resistance to one drug confers resistance to other chemically similar drugs or those that share mode of action. This aspect requires discovery of new anti-malarial compounds or formulation of new combination therapy. The current study attempts to contribute towards accelerating anti-malarial drug development efforts, by exploring the potential of existing FDA-approved drugs to target proteins of Plasmodium falciparum. METHODS Using comparative sequence and structure analyses, FDA-approved drugs, originally developed against other pathogens, were identified as potential repurpose-able candidates against P. falciparum. The rationale behind the undertaken approach is the likeliness of small molecules to bind to homologous targets. Such a study of evolutionary relationships between established targets and P. falciparum proteins aided in identification of approved drug candidates that can be explored for their anti-malarial potential. RESULTS Seventy-one FDA-approved drugs were identified that could be repurposed against P. falciparum. A total of 89 potential targets were recognized, of which about 70 are known to participate in parasite housekeeping machinery, protein biosynthesis, metabolic pathways and cell growth and differentiation, which can be prioritized for chemotherapeutic interventions. An additional aspect of prioritization of predicted repurpose-able drugs has been explored on the basis of ability of the drugs to permeate cell membranes, i.e., lipophilicity, since the parasite resides within a parasitophorous vacuole, within the erythrocyte, during the blood stages of infection. Based on this consideration, 46 of 71 FDA-approved drugs have been identified as feasible repurpose-able candidates against P. falciparum, and form a first-line for laboratory investigations. At least five of the drugs identified in the current analysis correspond to existing antibacterial agents already under use as repurposed anti-malarial agents. CONCLUSIONS The drug-target associations predicted, primarily by taking advantage of evolutionary information, provide a valuable resource of attractive and feasible candidate drugs that can be readily taken through further stages of anti-malarial drug development pipeline.
Collapse
Affiliation(s)
- Gayatri Ramakrishnan
- Indian Institute of Science Mathematics Initiative, Indian Institute of Science, Bangalore, 560012, India.,Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India.,Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Nagasuma Chandra
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | | |
Collapse
|
42
|
Jain V, Sharma A, Singh G, Yogavel M, Sharma A. Structure-Based Targeting of Orthologous Pathogen Proteins Accelerates Antiparasitic Drug Discovery. ACS Infect Dis 2017; 3:281-292. [PMID: 28195698 DOI: 10.1021/acsinfecdis.6b00181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Parasitic diseases caused by eukaryotic pathogens impose significant health and economic burden worldwide. The level of research funding available for many parasitic diseases is insufficient in relation to their adverse social and economic impact. In this article, we discuss that extant 3D structural data on protein-inhibitor complexes can be harnessed to accelerate drug discovery against many related pathogens. Assessment of sequence conservation within drug/inhibitor-binding residues in enzyme-inhibitor complexes can be leveraged to predict and validate both new lead compounds and their molecular targets in multiple parasitic diseases. Hence, structure-based targeting of orthologous pathogen proteins accelerates the discovery of new antiparasitic drugs. This approach offers significant benefits for jumpstarting the discovery of new lead compounds and their molecular targets in diverse human, livestock, and plant pathogens.
Collapse
Affiliation(s)
- Vitul Jain
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Road, New Delhi 110067, India
| | - Arvind Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Road, New Delhi 110067, India
| | - Gajinder Singh
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Road, New Delhi 110067, India
| | - Manickam Yogavel
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Road, New Delhi 110067, India
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Road, New Delhi 110067, India
| |
Collapse
|
43
|
Habib S, Vaishya S, Gupta K. Translation in Organelles of Apicomplexan Parasites. Trends Parasitol 2016; 32:939-952. [DOI: 10.1016/j.pt.2016.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/19/2016] [Accepted: 07/25/2016] [Indexed: 01/27/2023]
|
44
|
Targeting Protein Translation in Organelles of the Apicomplexa. Trends Parasitol 2016; 32:953-965. [DOI: 10.1016/j.pt.2016.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 12/15/2022]
|
45
|
Edwards RL, Odom John AR. Muddled mechanisms: recent progress towards antimalarial target identification. F1000Res 2016; 5:2514. [PMID: 27803804 PMCID: PMC5070598 DOI: 10.12688/f1000research.9477.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/06/2016] [Indexed: 01/06/2023] Open
Abstract
In the past decade, malaria rates have plummeted as a result of aggressive infection control measures and the adoption of artemisinin-based combination therapies (ACTs). However, a potential crisis looms ahead. Treatment failures to standard antimalarial regimens have been reported in Southeast Asia, and devastating consequences are expected if resistance spreads to the African continent. To prevent a potential public health emergency, the antimalarial arsenal must contain therapeutics with novel mechanisms of action (MOA). An impressive number of high-throughput screening (HTS) campaigns have since been launched, identifying thousands of compounds with activity against one of the causative agents of malaria,
Plasmodium falciparum. Now begins the difficult task of target identification, for which studies are often tedious, labor intensive, and difficult to interpret. In this review, we highlight approaches that have been instrumental in tackling the challenges of target assignment and elucidation of the MOA for hit compounds. Studies that apply these innovative techniques to antimalarial target identification are described, as well as the impact of the data in the field.
Collapse
Affiliation(s)
- Rachel L Edwards
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Audrey R Odom John
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
46
|
Wang X, Wedge DE, Cutler SJ. Chemical and Biological Study of Cladosporin, an Antimicrobial Inhibitor: A Review. Nat Prod Commun 2016. [DOI: 10.1177/1934578x1601101039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Natural antifungal agents are generally broad-spectrum compounds with low mammalian and environmental toxicity. Cladosporin is a naturally occurring fungal metabolite mainly isolated from the endophytic fungus Cladosporium cladosporioides. This review article summarizes the chemistry and biological properties of cladosporin covering references published from 1971–2016, including the source, phytochemical characterization, biosynthesis, total synthesis, structure and activity (SAR), and biological activity of cladosporin. Cladosporin exhibited potent antibacterial, antifungal, insecticidal, and anti-inflammatory activities, as well as plant growth regulatory effects. More importantly, cladosporin was identified as having potent, nanomolar, antiparasitic activity against both Plasmodium falciparum blood and liver stages via specific inhibition of protein synthesis. This provides a new approach for the design of isocoumarin-based compounds for the treatment of malaria. Herbicidal activity and antifungal activity against Cryptococcus neoformans (IC50value of 17.7 μg/mL) of cladosporin are also described here in the review for the first time. Cladosporin selectively inhibited the growth of a monocot (agostis) and showed no activity against a dicot (lettuce), which indicates its great potential as a selective herbicide for monocots in agriculture use. The above data suggest that cladosporin has great potential utility as a lead compound in the development of agrochemicals against certain plant pathogens and pharmaceuticals against drug-resistant bacteria and parasites.
Collapse
Affiliation(s)
- Xiaoning Wang
- Chemical Synthesis & Drug Discovery Facility and Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - David E Wedge
- Agricultural Research Service, Natural Products Utilization Research Unit, U.S. Department of Agriculture, University of Mississippi, University, MS 38677, USA
| | - Stephen J Cutler
- Department of BioMolecular Sciences and National Center for Natural Products Research, University of Mississippi, University, MS 38677, USA
| |
Collapse
|
47
|
Cryptosporidium and Toxoplasma Parasites Are Inhibited by a Benzoxaborole Targeting Leucyl-tRNA Synthetase. Antimicrob Agents Chemother 2016; 60:5817-27. [PMID: 27431220 PMCID: PMC5038320 DOI: 10.1128/aac.00873-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/07/2016] [Indexed: 11/20/2022] Open
Abstract
The apicomplexan parasites Cryptosporidium and Toxoplasma are serious threats to human health. Cryptosporidiosis is a severe diarrheal disease in malnourished children and immunocompromised individuals, with the only FDA-approved drug treatment currently being nitazoxanide. The existing therapies for toxoplasmosis, an important pathology in immunocompromised individuals and pregnant women, also have serious limitations. With the aim of developing alternative therapeutic options to address these health problems, we tested a number of benzoxaboroles, boron-containing compounds shown to be active against various infectious agents, for inhibition of the growth of Cryptosporidium parasites in mammalian cells. A 3-aminomethyl benzoxaborole, AN6426, with activity in the micromolar range and with activity comparable to that of nitazoxanide, was identified and further characterized using biophysical measurements of affinity and crystal structures of complexes with the editing domain of Cryptosporidium leucyl-tRNA synthetase (LeuRS). The same compound was shown to be active against Toxoplasma parasites, with the activity being enhanced in the presence of norvaline, an amino acid that can be mischarged by LeuRS. Our observations are consistent with AN6426 inhibiting protein synthesis in both Cryptosporidium and Toxoplasma by forming a covalent adduct with tRNA(Leu) in the LeuRS editing active site and suggest that further exploitation of the benzoxaborole scaffold is a valid strategy to develop novel, much needed antiparasitic agents.
Collapse
|
48
|
Diversity-oriented synthesis yields novel multistage antimalarial inhibitors. Nature 2016; 538:344-349. [PMID: 27602946 DOI: 10.1038/nature19804] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 08/31/2016] [Indexed: 02/08/2023]
Abstract
Antimalarial drugs have thus far been chiefly derived from two sources-natural products and synthetic drug-like compounds. Here we investigate whether antimalarial agents with novel mechanisms of action could be discovered using a diverse collection of synthetic compounds that have three-dimensional features reminiscent of natural products and are underrepresented in typical screening collections. We report the identification of such compounds with both previously reported and undescribed mechanisms of action, including a series of bicyclic azetidines that inhibit a new antimalarial target, phenylalanyl-tRNA synthetase. These molecules are curative in mice at a single, low dose and show activity against all parasite life stages in multiple in vivo efficacy models. Our findings identify bicyclic azetidines with the potential to both cure and prevent transmission of the disease as well as protect at-risk populations with a single oral dose, highlighting the strength of diversity-oriented synthesis in revealing promising therapeutic targets.
Collapse
|
49
|
Antimalarial Benzoxaboroles Target Plasmodium falciparum Leucyl-tRNA Synthetase. Antimicrob Agents Chemother 2016; 60:4886-95. [PMID: 27270277 DOI: 10.1128/aac.00820-16] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/26/2016] [Indexed: 01/18/2023] Open
Abstract
There is a need for new antimalarials, ideally with novel mechanisms of action. Benzoxaboroles have been shown to be active against bacteria, fungi, and trypanosomes. Therefore, we investigated the antimalarial activity and mechanism of action of 3-aminomethyl benzoxaboroles against Plasmodium falciparum Two 3-aminomethyl compounds, AN6426 and AN8432, demonstrated good potency against cultured multidrug-resistant (W2 strain) P. falciparum (50% inhibitory concentration [IC50] of 310 nM and 490 nM, respectively) and efficacy against murine Plasmodium berghei infection when administered orally once daily for 4 days (90% effective dose [ED90], 7.4 and 16.2 mg/kg of body weight, respectively). To characterize mechanisms of action, we selected parasites with decreased drug sensitivity by culturing with stepwise increases in concentration of AN6426. Resistant clones were characterized by whole-genome sequencing. Three generations of resistant parasites had polymorphisms in the predicted editing domain of the gene encoding a P. falciparum leucyl-tRNA synthetase (LeuRS; PF3D7_0622800) and in another gene (PF3D7_1218100), which encodes a protein of unknown function. Solution of the structure of the P. falciparum LeuRS editing domain suggested key roles for mutated residues in LeuRS editing. Short incubations with AN6426 and AN8432, unlike artemisinin, caused dose-dependent inhibition of [(14)C]leucine incorporation by cultured wild-type, but not resistant, parasites. The growth of resistant, but not wild-type, parasites was impaired in the presence of the unnatural amino acid norvaline, consistent with a loss of LeuRS editing activity in resistant parasites. In summary, the benzoxaboroles AN6426 and AN8432 offer effective antimalarial activity and act, at least in part, against a novel target, the editing domain of P. falciparum LeuRS.
Collapse
|
50
|
Pasaje CFA, Cheung V, Kennedy K, Lim EE, Baell JB, Griffin MDW, Ralph SA. Selective inhibition of apicoplast tryptophanyl-tRNA synthetase causes delayed death in Plasmodium falciparum. Sci Rep 2016; 6:27531. [PMID: 27277538 PMCID: PMC4899734 DOI: 10.1038/srep27531] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/19/2016] [Indexed: 11/11/2022] Open
Abstract
The malaria parasite Plasmodium falciparum relies on efficient protein translation. An essential component of translation is the tryptophanyl-tRNA synthetase (TrpRS) that charges tRNAtrp. Here we characterise two isoforms of TrpRS in Plasmodium; one eukaryotic type localises to the cytosol and a bacterial type localises to the remnant plastid (apicoplast). We show that the apicoplast TrpRS aminoacylates bacterial tRNAtrp while the cytosolic TrpRS charges eukaryotic tRNAtrp. An inhibitor of bacterial TrpRSs, indolmycin, specifically inhibits aminoacylation by the apicoplast TrpRS in vitro, and inhibits ex vivo Plasmodium parasite growth, killing parasites with a delayed death effect characteristic of apicoplast inhibitors. Indolmycin treatment ablates apicoplast inheritance and is rescuable by addition of the apicoplast metabolite isopentenyl pyrophosphate (IPP). These data establish that inhibition of an apicoplast housekeeping enzyme leads to loss of the apicoplast and this is sufficient for delayed death. Apicoplast TrpRS is essential for protein translation and is a promising, specific antimalarial target.
Collapse
Affiliation(s)
- Charisse Flerida A Pasaje
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Vanessa Cheung
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Kit Kennedy
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Erin E Lim
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Jonathan B Baell
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, 3052 Victoria, Australia
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| |
Collapse
|