1
|
Chen W, Zou R, Mei Y, Li J, Xuan Y, Cui B, Zou J, Wang J, Lin S, Zhang Z, Wang C. Structural insights into drug transport by an aquaglyceroporin. Nat Commun 2024; 15:3985. [PMID: 38734677 PMCID: PMC11088622 DOI: 10.1038/s41467-024-48445-4] [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: 10/29/2023] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Pentamidine and melarsoprol are primary drugs used to treat the lethal human sleeping sickness caused by the parasite Trypanosoma brucei. Cross-resistance to these two drugs has recently been linked to aquaglyceroporin 2 of the trypanosome (TbAQP2). TbAQP2 is the first member of the aquaporin family described as capable of drug transport; however, the underlying mechanism remains unclear. Here, we present cryo-electron microscopy structures of TbAQP2 bound to pentamidine or melarsoprol. Our structural studies, together with the molecular dynamic simulations, reveal the mechanisms shaping substrate specificity and drug permeation. Multiple amino acids in TbAQP2, near the extracellular entrance and inside the pore, create an expanded conducting tunnel, sterically and energetically allowing the permeation of pentamidine and melarsoprol. Our study elucidates the mechanism of drug transport by TbAQP2, providing valuable insights to inform the design of drugs against trypanosomiasis.
Collapse
Affiliation(s)
- Wanbiao Chen
- Center for Human Tissues and Organs Degeneration, Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 581055, China
| | - Rongfeng Zou
- Shenzhen Jingtai Technology Co., Ltd. (XtalPi), Shenzhen, 518000, China
| | - Yi Mei
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Jiawei Li
- Center for Human Tissues and Organs Degeneration, Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 581055, China
- Department of Geriatric Medicine, Shenzhen Longhua District Central Hospital, Shenzhen, 518110, China
| | - Yumi Xuan
- Center for Human Tissues and Organs Degeneration, Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 581055, China
| | - Bing Cui
- Center for Human Tissues and Organs Degeneration, Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 581055, China
- School of Basic Medicine and Clinical Pharmacy, and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Junjie Zou
- Shenzhen Jingtai Technology Co., Ltd. (XtalPi), Shenzhen, 518000, China
| | - Juncheng Wang
- Advanced Medical Research Institute, Shandong University, Jinan, China
| | - Shaoquan Lin
- Centre for Polymers in Medicine, Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen, 581055, China
| | - Zhe Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China.
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China.
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China.
| | - Chongyuan Wang
- Center for Human Tissues and Organs Degeneration, Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 581055, China.
| |
Collapse
|
2
|
Jamabo M, Mahlalela M, Edkins AL, Boshoff A. Tackling Sleeping Sickness: Current and Promising Therapeutics and Treatment Strategies. Int J Mol Sci 2023; 24:12529. [PMID: 37569903 PMCID: PMC10420020 DOI: 10.3390/ijms241512529] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/27/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Human African trypanosomiasis is a neglected tropical disease caused by the extracellular protozoan parasite Trypanosoma brucei, and targeted for eradication by 2030. The COVID-19 pandemic contributed to the lengthening of the proposed time frame for eliminating human African trypanosomiasis as control programs were interrupted. Armed with extensive antigenic variation and the depletion of the B cell population during an infectious cycle, attempts to develop a vaccine have remained unachievable. With the absence of a vaccine, control of the disease has relied heavily on intensive screening measures and the use of drugs. The chemotherapeutics previously available for disease management were plagued by issues such as toxicity, resistance, and difficulty in administration. The approval of the latest and first oral drug, fexinidazole, is a major chemotherapeutic achievement for the treatment of human African trypanosomiasis in the past few decades. Timely and accurate diagnosis is essential for effective treatment, while poor compliance and resistance remain outstanding challenges. Drug discovery is on-going, and herein we review the recent advances in anti-trypanosomal drug discovery, including novel potential drug targets. The numerous challenges associated with disease eradication will also be addressed.
Collapse
Affiliation(s)
- Miebaka Jamabo
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Maduma Mahlalela
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Adrienne L. Edkins
- Department of Biochemistry and Microbiology, Biomedical Biotechnology Research Centre (BioBRU), Rhodes University, Makhanda 6139, South Africa;
| | - Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| |
Collapse
|
3
|
Schmidt JDR, Beitz E. Mutational Widening of Constrictions in a Formate-Nitrite/H + Transporter Enables Aquaporin-Like Water Permeability and Proton Conductance. J Biol Chem 2021; 298:101513. [PMID: 34929166 PMCID: PMC8749060 DOI: 10.1016/j.jbc.2021.101513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 11/30/2022] Open
Abstract
The unrelated protein families of the microbial formate–nitrite transporters (FNTs) and aquaporins (AQP) likely adapted the same protein fold through convergent evolution. FNTs facilitate weak acid anion/H+ cotransport, whereas AQP water channels strictly exclude charged substrates including protons. The FNT channel–like transduction pathway bears two lipophilic constriction sites that sandwich a highly conserved histidine residue. Because of lacking experiments, the function of these constrictions is unclear, and the protonation status of the central histidine during substrate transport remains a matter of debate. Here, we introduced constriction-widening mutations into the prototypical FNT from Escherichia coli, FocA, and assayed formate/H+ transport properties, water/solute permeability, and proton conductance. We found that enlargement of these constrictions concomitantly decreased formate/formic acid transport. In contrast to wildtype FocA, the mutants were unable to make use of a transmembrane proton gradient as a driving force. A construct in which both constrictions were eliminated exhibited water permeability, similar to AQPs, although accompanied by a proton conductance. Our data indicate that the lipophilic constrictions mainly act as barriers to isolate the central histidine from the aqueous bulk preventing protonation via proton wires. These results are supportive of an FNT transport model in which the central histidine is uncharged, and weak acid substrate anion protonation occurs in the vestibule regions of the transporter before passing the constrictions.
Collapse
Affiliation(s)
- Jana D R Schmidt
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany.
| |
Collapse
|
4
|
Quintana JF, Field MC. Evolution, function and roles in drug sensitivity of trypanosome aquaglyceroporins. Parasitology 2021; 148:1137-1142. [PMID: 33602349 PMCID: PMC8311954 DOI: 10.1017/s0031182021000354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/10/2021] [Accepted: 02/15/2021] [Indexed: 12/13/2022]
Abstract
Aquaglyceroporins (AQPs) are membrane proteins that function in osmoregulation and the uptake of low molecular weight solutes, in particular glycerol and urea. The AQP family is highly conserved, with two major subfamilies having arisen very early in prokaryote evolution and retained by eukaryotes. A complex evolutionary history indicates multiple lineage-specific expansions, losses and not uncommonly a complete loss. Consequently, the AQP family is highly evolvable and has been associated with significant events in life on Earth. In the African trypanosomes, a role for the AQP2 paralogue, in sensitivity to two chemotherapeutic agents, pentamidine and melarsoprol, is well established, albeit with the mechanisms for cell entry and resistance unclear until very recently. Here, we discuss AQP evolution, structure and mechanisms by which AQPs impact drug sensitivity, suggesting that AQP2 stability is highly sensitive to mutation while serving as the major uptake pathway for pentamidine.
Collapse
Affiliation(s)
- Juan F. Quintana
- Wellcome Centre for Integrative Parasitology (WCIP), Institute of Biodiversity, Animal Health and Comparative Medicine (IBAHCM), University of Glasgow, GlasgowG61 1QH, UK
| | - Mark C. Field
- School of Life Sciences, University of Dundee, DundeeDD1 5EH, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005Ceske Budejovice, Czech Republic
| |
Collapse
|
5
|
AQPX-cluster aquaporins and aquaglyceroporins are asymmetrically distributed in trypanosomes. Commun Biol 2021; 4:953. [PMID: 34376792 PMCID: PMC8355241 DOI: 10.1038/s42003-021-02472-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Major Intrinsic Proteins (MIPs) are membrane channels that permeate water and other small solutes. Some trypanosomatid MIPs mediate the uptake of antiparasitic compounds, placing them as potential drug targets. However, a thorough study of the diversity of these channels is still missing. Here we place trypanosomatid channels in the sequence-function space of the large MIP superfamily through a sequence similarity network. This analysis exposes that trypanosomatid aquaporins integrate a distant cluster from the currently defined MIP families, here named aquaporin X (AQPX). Our phylogenetic analyses reveal that trypanosomatid MIPs distribute exclusively between aquaglyceroporin (GLP) and AQPX, being the AQPX family expanded in the Metakinetoplastina common ancestor before the origin of the parasitic order Trypanosomatida. Synteny analysis shows how African trypanosomes specifically lost AQPXs, whereas American trypanosomes specifically lost GLPs. AQPXs diverge from already described MIPs on crucial residues. Together, our results expose the diversity of trypanosomatid MIPs and will aid further functional, structural, and physiological research needed to face the potentiality of the AQPXs as gateways for trypanocidal drugs.
Collapse
|
6
|
Wargnies M, Plazolles N, Schenk R, Villafraz O, Dupuy JW, Biran M, Bachmaier S, Baudouin H, Clayton C, Boshart M, Bringaud F. Metabolic selection of a homologous recombination-mediated gene loss protects Trypanosoma brucei from ROS production by glycosomal fumarate reductase. J Biol Chem 2021; 296:100548. [PMID: 33741344 PMCID: PMC8065229 DOI: 10.1016/j.jbc.2021.100548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/08/2021] [Accepted: 03/15/2021] [Indexed: 11/23/2022] Open
Abstract
The genome of trypanosomatids rearranges by using repeated sequences as platforms for amplification or deletion of genomic segments. These stochastic recombination events have a direct impact on gene dosage and foster the selection of adaptive traits in response to environmental pressure. We provide here such an example by showing that the phosphoenolpyruvate carboxykinase (PEPCK) gene knockout (Δpepck) leads to the selection of a deletion event between two tandemly arranged fumarate reductase (FRDg and FRDm2) genes to produce a chimeric FRDg-m2 gene in the Δpepck∗ cell line. FRDg is expressed in peroxisome-related organelles, named glycosomes, expression of FRDm2 has not been detected to date, and FRDg-m2 is nonfunctional and cytosolic. Re-expression of FRDg significantly impaired growth of the Δpepck∗ cells, but FRD enzyme activity was not required for this negative effect. Instead, glycosomal localization as well as the covalent flavinylation motif of FRD is required to confer growth retardation and intracellular accumulation of reactive oxygen species (ROS). The data suggest that FRDg, similar to Escherichia coli FRD, can generate ROS in a flavin-dependent process by transfer of electrons from NADH to molecular oxygen instead of fumarate when the latter is unavailable, as in the Δpepck background. Hence, growth retardation is interpreted as a consequence of increased production of ROS, and rearrangement of the FRD locus liberates Δpepck∗ cells from this obstacle. Interestingly, intracellular production of ROS has been shown to be required to complete the parasitic cycle in the insect vector, suggesting that FRDg may play a role in this process.
Collapse
Affiliation(s)
- Marion Wargnies
- Univ. Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234, Bordeaux, France; Univ. Bordeaux, CNRS, Centre de Résonance Magnétique des Systèmes Biologiques (CRMSB), UMR 5536, Bordeaux, France
| | - Nicolas Plazolles
- Univ. Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234, Bordeaux, France
| | - Robin Schenk
- Fakultät für Biologie, Genetik, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Oriana Villafraz
- Univ. Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234, Bordeaux, France
| | | | - Marc Biran
- Univ. Bordeaux, CNRS, Centre de Résonance Magnétique des Systèmes Biologiques (CRMSB), UMR 5536, Bordeaux, France
| | - Sabine Bachmaier
- Fakultät für Biologie, Genetik, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Hélène Baudouin
- Univ. Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234, Bordeaux, France; Univ. Bordeaux, CNRS, Centre de Résonance Magnétique des Systèmes Biologiques (CRMSB), UMR 5536, Bordeaux, France
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZBMH), Universität Heidelberg, Heidelberg, Germany
| | - Michael Boshart
- Fakultät für Biologie, Genetik, Ludwig-Maximilians-Universität München, Martinsried, Germany.
| | - Frédéric Bringaud
- Univ. Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234, Bordeaux, France; Univ. Bordeaux, CNRS, Centre de Résonance Magnétique des Systèmes Biologiques (CRMSB), UMR 5536, Bordeaux, France.
| |
Collapse
|
7
|
Azad AK, Raihan T, Ahmed J, Hakim A, Emon TH, Chowdhury PA. Human Aquaporins: Functional Diversity and Potential Roles in Infectious and Non-infectious Diseases. Front Genet 2021; 12:654865. [PMID: 33796134 PMCID: PMC8007926 DOI: 10.3389/fgene.2021.654865] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 02/22/2021] [Indexed: 12/11/2022] Open
Abstract
Aquaporins (AQPs) are integral membrane proteins and found in all living organisms from bacteria to human. AQPs mainly involved in the transmembrane diffusion of water as well as various small solutes in a bidirectional manner are widely distributed in various human tissues. Human contains 13 AQPs (AQP0-AQP12) which are divided into three sub-classes namely orthodox aquaporin (AQP0, 1, 2, 4, 5, 6, and 8), aquaglyceroporin (AQP3, 7, 9, and 10) and super or unorthodox aquaporin (AQP11 and 12) based on their pore selectivity. Human AQPs are functionally diverse, which are involved in wide variety of non-infectious diseases including cancer, renal dysfunction, neurological disorder, epilepsy, skin disease, metabolic syndrome, and even cardiac diseases. However, the association of AQPs with infectious diseases has not been fully evaluated. Several studies have unveiled that AQPs can be regulated by microbial and parasitic infections that suggest their involvement in microbial pathogenesis, inflammation-associated responses and AQP-mediated cell water homeostasis. This review mainly aims to shed light on the involvement of AQPs in infectious and non-infectious diseases and potential AQPs-target modulators. Furthermore, AQP structures, tissue-specific distributions and their physiological relevance, functional diversity and regulations have been discussed. Altogether, this review would be useful for further investigation of AQPs as a potential therapeutic target for treatment of infectious as well as non-infectious diseases.
Collapse
Affiliation(s)
- Abul Kalam Azad
- Department of Genetic Engineering and Biotechnology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Topu Raihan
- Department of Genetic Engineering and Biotechnology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Jahed Ahmed
- Department of Genetic Engineering and Biotechnology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, Bangladesh
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Al Hakim
- Department of Genetic Engineering and Biotechnology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Tanvir Hossain Emon
- Department of Genetic Engineering and Biotechnology, School of Life Sciences, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | | |
Collapse
|
8
|
Schmidt JDR, Walloch P, Höger B, Beitz E. Aquaporins with lactate/lactic acid permeability at physiological pH conditions. Biochimie 2021; 188:7-11. [PMID: 33577940 DOI: 10.1016/j.biochi.2021.01.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 10/22/2022]
Abstract
The spectrum of putative and experimentally shown permeants of cellular water and solute channels of the ubiquitous aquaporin family is still increasing. Virtually all AQP substrates, e.g. water, glycerol, urea, hydrogen peroxide, or carbon dioxide, are permanently neutral small molecule compounds. Several reports, however, describe aquaporins that exhibit lactate permeability. Lactate in aqueous solution undergoes a pH-dependent protonation equilibrium with neutral lactic acid, which likely represents the actual substrate form passing the aquaporin channel. Certain aquaporins, however, appear to be better geared for lactate/lactic acid permeability even at low proton availability. Here, we discuss the structural properties of such aquaporins and compare them to the microbial protein family of the formate-nitrite (lactate) transporters that assume the aquaporin fold despite unrelated protein sequences.
Collapse
Affiliation(s)
- Jana D R Schmidt
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Philipp Walloch
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Bastian Höger
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany.
| |
Collapse
|
9
|
The Ionophores CCCP and Gramicidin but Not Nigericin Inhibit Trypanosoma brucei Aquaglyceroporins at Neutral pH. Cells 2020; 9:cells9102335. [PMID: 33096791 PMCID: PMC7589649 DOI: 10.3390/cells9102335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/16/2022] Open
Abstract
Human African trypanosomiasis (HAT) is caused by Trypanosoma brucei parasites. The T. brucei aquaglyceroporin isoform 2, TbAQP2, has been linked to the uptake of pentamidine. Negative membrane potentials and transmembrane pH gradients were suggested to promote transport of the dicationic antitrypanosomal drug. Application of ionophores to trypanosomes further hinted at direct inhibition of TbAQP2 by carbonyl cyanide m-chlorophenyl hydrazone (CCCP). Here, we tested for direct effects of three classical ionophores (CCCP, nigericin, gramicidin) on the functionality of TbAQP2 and the related TbAQP3 at conditions that are independent from the membrane potential or a proton gradient. We expressed TbAQP2 and TbAQP3 in yeast, and determined permeability of uncharged glycerol at neutral pH using stopped-flow light scattering. The mobile proton carrier CCCP directly inhibited TbAQP2 glycerol permeability at an IC50 of 2 µM, and TbAQP3 to a much lesser extent (IC50 around 1 mM) likely due to different selectivity filter layouts. Nigericin, another mobile carrier, left both isoforms unaffected. The membrane-integral pore-forming gramicidin evenly inhibited TbAQP2 and TbAQP2 in the double-digit micromolar range. Our data exemplify the need for suitable controls to detect unwanted ionophore side effects even when used at concentrations that are typically recommended to disturb the transmembrane ion distribution.
Collapse
|
10
|
Alghamdi AH, Munday JC, Campagnaro GD, Gurvic D, Svensson F, Okpara CE, Kumar A, Quintana J, Martin Abril ME, Milić P, Watson L, Paape D, Settimo L, Dimitriou A, Wielinska J, Smart G, Anderson LF, Woodley CM, Kelly SPY, Ibrahim HM, Hulpia F, Al-Salabi MI, Eze AA, Sprenger T, Teka IA, Gudin S, Weyand S, Field M, Dardonville C, Tidwell RR, Carrington M, O'Neill P, Boykin DW, Zachariae U, De Koning HP. Positively selected modifications in the pore of TbAQP2 allow pentamidine to enter Trypanosoma brucei. eLife 2020; 9:56416. [PMID: 32762841 PMCID: PMC7473772 DOI: 10.7554/elife.56416] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 08/06/2020] [Indexed: 11/25/2022] Open
Abstract
Mutations in the Trypanosoma brucei aquaporin AQP2 are associated with resistance to pentamidine and melarsoprol. We show that TbAQP2 but not TbAQP3 was positively selected for increased pore size from a common ancestor aquaporin. We demonstrate that TbAQP2’s unique architecture permits pentamidine permeation through its central pore and show how specific mutations in highly conserved motifs affect drug permeation. Introduction of key TbAQP2 amino acids into TbAQP3 renders the latter permeable to pentamidine. Molecular dynamics demonstrates that permeation by dicationic pentamidine is energetically favourable in TbAQP2, driven by the membrane potential, although aquaporins are normally strictly impermeable for ionic species. We also identify the structural determinants that make pentamidine a permeant although most other diamidine drugs are excluded. Our results have wide-ranging implications for optimising antitrypanosomal drugs and averting cross-resistance. Moreover, these new insights in aquaporin permeation may allow the pharmacological exploitation of other members of this ubiquitous gene family. African sleeping sickness is a potentially deadly illness caused by the parasite Trypanosoma brucei. The disease is treatable, but many of the current treatments are old and are becoming increasingly ineffective. For instance, resistance is growing against pentamidine, a drug used in the early stages in the disease, as well as against melarsoprol, which is deployed when the infection has progressed to the brain. Usually, cases resistant to pentamidine are also resistant to melarsoprol, but it is still unclear why, as the drugs are chemically unrelated. Studies have shown that changes in a water channel called aquaglyceroporin 2 (TbAQP2) contribute to drug resistance in African sleeping sickness; this suggests that it plays a role in allowing drugs to kill the parasite. This molecular ‘drain pipe’ extends through the surface of T. brucei, and should allow only water and a molecule called glycerol in and out of the cell. In particular, the channel should be too narrow to allow pentamidine or melarsoprol to pass through. One possibility is that, in T. brucei, the TbAQP2 channel is abnormally wide compared to other members of its family. Alternatively, pentamidine and melarsoprol may only bind to TbAQP2, and then ‘hitch a ride’ when the protein is taken into the parasite as part of the natural cycle of surface protein replacement. Alghamdi et al. aimed to tease out these hypotheses. Computer models of the structure of the protein were paired with engineered changes in the key areas of the channel to show that, in T. brucei, TbAQP2 provides a much broader gateway into the cell than observed for similar proteins. In addition, genetic analysis showed that this version of TbAQP2 has been actively selected for during the evolution process of T. brucei. This suggests that the parasite somehow benefits from this wider aquaglyceroporin variant. This is a new resistance mechanism, and it is possible that aquaglyceroporins are also larger than expected in other infectious microbes. The work by Alghamdi et al. therefore provides insight into how other germs may become resistant to drugs.
Collapse
Affiliation(s)
- Ali H Alghamdi
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | | | - Dominik Gurvic
- Computational Biology Centre for Translational and Interdisciplinary Research, University of Dundee, Dundee, United Kingdom
| | - Fredrik Svensson
- IOTA Pharmaceuticals Ltd, St Johns Innovation Centre, Cambridge, United Kingdom
| | - Chinyere E Okpara
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Arvind Kumar
- Chemistry Department, Georgia State University, Atlanta, United States
| | - Juan Quintana
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Patrik Milić
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Laura Watson
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Daniel Paape
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Luca Settimo
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Anna Dimitriou
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Joanna Wielinska
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Graeme Smart
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Laura F Anderson
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | | | - Siu Pui Ying Kelly
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Hasan Ms Ibrahim
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Fabian Hulpia
- Laboratory for Medicinal Chemistry, University of Ghent, Ghent, Belgium
| | - Mohammed I Al-Salabi
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Anthonius A Eze
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Teresa Sprenger
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ibrahim A Teka
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simon Gudin
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simone Weyand
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mark Field
- School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | | | - Richard R Tidwell
- Department of Pathology and Lab Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Paul O'Neill
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - David W Boykin
- Chemistry Department, Georgia State University, Atlanta, United States
| | - Ulrich Zachariae
- Computational Biology Centre for Translational and Interdisciplinary Research, University of Dundee, Dundee, United Kingdom
| | - Harry P De Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
11
|
Quintana JF, Bueren-Calabuig J, Zuccotto F, de Koning HP, Horn D, Field MC. Instability of aquaglyceroporin (AQP) 2 contributes to drug resistance in Trypanosoma brucei. PLoS Negl Trop Dis 2020; 14:e0008458. [PMID: 32644992 PMCID: PMC7413563 DOI: 10.1371/journal.pntd.0008458] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 08/07/2020] [Accepted: 06/05/2020] [Indexed: 12/26/2022] Open
Abstract
Defining mode of action is vital for both developing new drugs and predicting potential resistance mechanisms. Sensitivity of African trypanosomes to pentamidine and melarsoprol is predominantly mediated by aquaglyceroporin 2 (TbAQP2), a channel associated with water/glycerol transport. TbAQP2 is expressed at the flagellar pocket membrane and chimerisation with TbAQP3 renders parasites resistant to both drugs. Two models for how TbAQP2 mediates pentamidine sensitivity have emerged; that TbAQP2 mediates pentamidine translocation across the plasma membrane or via binding to TbAQP2, with subsequent endocytosis and presumably transport across the endosomal/lysosomal membrane, but as trafficking and regulation of TbAQPs is uncharacterised this remains unresolved. We demonstrate that TbAQP2 is organised as a high order complex, is ubiquitylated and is transported to the lysosome. Unexpectedly, mutation of potential ubiquitin conjugation sites, i.e. cytoplasmic-oriented lysine residues, reduced folding and tetramerization efficiency and triggered ER retention. Moreover, TbAQP2/TbAQP3 chimerisation, as observed in pentamidine-resistant parasites, also leads to impaired oligomerisation, mislocalisation and increased turnover. These data suggest that TbAQP2 stability is highly sensitive to mutation and that instability contributes towards the emergence of drug resistance.
Collapse
Affiliation(s)
- Juan F. Quintana
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Juan Bueren-Calabuig
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Fabio Zuccotto
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Harry P. de Koning
- Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - David Horn
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Mark C. Field
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| |
Collapse
|
12
|
Álvarez-Bardón M, Pérez-Pertejo Y, Ordóñez C, Sepúlveda-Crespo D, Carballeira NM, Tekwani BL, Murugesan S, Martinez-Valladares M, García-Estrada C, Reguera RM, Balaña-Fouce R. Screening Marine Natural Products for New Drug Leads against Trypanosomatids and Malaria. Mar Drugs 2020; 18:E187. [PMID: 32244488 PMCID: PMC7230869 DOI: 10.3390/md18040187] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023] Open
Abstract
Neglected Tropical Diseases (NTD) represent a serious threat to humans, especially for those living in poor or developing countries. Almost one-sixth of the world population is at risk of suffering from these diseases and many thousands die because of NTDs, to which we should add the sanitary, labor and social issues that hinder the economic development of these countries. Protozoan-borne diseases are responsible for more than one million deaths every year. Visceral leishmaniasis, Chagas disease or sleeping sickness are among the most lethal NTDs. Despite not being considered an NTD by the World Health Organization (WHO), malaria must be added to this sinister group. Malaria, caused by the apicomplexan parasite Plasmodium falciparum, is responsible for thousands of deaths each year. The treatment of this disease has been losing effectiveness year after year. Many of the medicines currently in use are obsolete due to their gradual loss of efficacy, their intrinsic toxicity and the emergence of drug resistance or a lack of adherence to treatment. Therefore, there is an urgent and global need for new drugs. Despite this, the scant interest shown by most of the stakeholders involved in the pharmaceutical industry makes our present therapeutic arsenal scarce, and until recently, the search for new drugs has not been seriously addressed. The sources of new drugs for these and other pathologies include natural products, synthetic molecules or repurposing drugs. The most frequent sources of natural products are microorganisms, e.g., bacteria, fungi, yeasts, algae and plants, which are able to synthesize many drugs that are currently in use (e.g. antimicrobials, antitumor, immunosuppressants, etc.). The marine environment is another well-established source of bioactive natural products, with recent applications against parasites, bacteria and other pathogens which affect humans and animals. Drug discovery techniques have rapidly advanced since the beginning of the millennium. The combination of novel techniques that include the genetic modification of pathogens, bioimaging and robotics has given rise to the standardization of High-Performance Screening platforms in the discovery of drugs. These advancements have accelerated the discovery of new chemical entities with antiparasitic effects. This review presents critical updates regarding the use of High-Throughput Screening (HTS) in the discovery of drugs for NTDs transmitted by protozoa, including malaria, and its application in the discovery of new drugs of marine origin.
Collapse
Affiliation(s)
- María Álvarez-Bardón
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Yolanda Pérez-Pertejo
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - César Ordóñez
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Daniel Sepúlveda-Crespo
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Nestor M. Carballeira
- Department of Chemistry, University of Puerto Rico, Río Piedras 00925-2537, San Juan, Puerto Rico;
| | - Babu L. Tekwani
- Department of Infectious Diseases, Division of Drug Discovery, Southern Research, Birmingham, AL 35205, USA;
| | - Sankaranarayanan Murugesan
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Vidya Vihar, Pilani 333031, India;
| | - Maria Martinez-Valladares
- Department of Animal Health, Instituto de Ganadería de Montaña (CSIC-Universidad de León), Grulleros, 24346 León, Spain;
| | - Carlos García-Estrada
- INBIOTEC (Instituto de Biotecnología de León), Avda. Real 1-Parque Científico de León, 24006 León, Spain;
| | - Rosa M. Reguera
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Rafael Balaña-Fouce
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| |
Collapse
|
13
|
|
14
|
P De Koning H. The Drugs of Sleeping Sickness: Their Mechanisms of Action and Resistance, and a Brief History. Trop Med Infect Dis 2020; 5:E14. [PMID: 31963784 PMCID: PMC7157662 DOI: 10.3390/tropicalmed5010014] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 12/17/2022] Open
Abstract
With the incidence of sleeping sickness in decline and genuine progress being made towards the WHO goal of eliminating sleeping sickness as a major public health concern, this is a good moment to evaluate the drugs that 'got the job done': their development, their limitations and the resistance that the parasites developed against them. This retrospective looks back on the remarkable story of chemotherapy against trypanosomiasis, a story that goes back to the very origins and conception of chemotherapy in the first years of the 20 century and is still not finished today.
Collapse
Affiliation(s)
- Harry P De Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK
| |
Collapse
|
15
|
Akazue PI, Ebiloma GU, Ajibola O, Isaac C, Onyekwelu K, Ezeh CO, Eze AA. Sustainable Elimination (Zero Cases) of Sleeping Sickness: How Far Are We from Achieving This Goal? Pathogens 2019; 8:E135. [PMID: 31470522 PMCID: PMC6789789 DOI: 10.3390/pathogens8030135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 01/02/2023] Open
Abstract
The recent massive reduction in the numbers of fresh Human African Trypanosomiasis (HAT) infection has presented an opportunity for the global elimination of this disease. To prevent a possible resurgence, as was the case after the reduced transmission of the 1960s, surveillance needs to be sustained and the necessary tools for detection and treatment of cases need to be made available at the points of care. In this review, we examine the available resources and make recommendations for improvement to ensure the sustenance of the already achieved gains to keep the trend moving towards elimination.
Collapse
Affiliation(s)
- Pearl Ihuoma Akazue
- Department of Biochemistry, Faculty of Life Sciences, University of Benin, Benin City 300283, Nigeria
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Olumide Ajibola
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul PO Box 273, The Gambia
| | - Clement Isaac
- Department of Zoology, Faculty of Life Sciences, Ambrose Alli University, Ekpoma 310101, Nigeria
| | - Kenechukwu Onyekwelu
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria
| | - Charles O Ezeh
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria
| | - Anthonius Anayochukwu Eze
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria.
| |
Collapse
|
16
|
Chemogenomic Profiling of Antileishmanial Efficacy and Resistance in the Related Kinetoplastid Parasite Trypanosoma brucei. Antimicrob Agents Chemother 2019; 63:AAC.00795-19. [PMID: 31160283 PMCID: PMC6658743 DOI: 10.1128/aac.00795-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 05/23/2019] [Indexed: 01/01/2023] Open
Abstract
The arsenal of drugs used to treat leishmaniasis, caused by Leishmania spp., is limited and beset by toxicity and emergent resistance. Furthermore, our understanding of drug mode of action and potential routes to resistance is limited. Forward genetic approaches have revolutionized our understanding of drug mode of action in the related kinetoplastid parasite Trypanosoma brucei. The arsenal of drugs used to treat leishmaniasis, caused by Leishmania spp., is limited and beset by toxicity and emergent resistance. Furthermore, our understanding of drug mode of action and potential routes to resistance is limited. Forward genetic approaches have revolutionized our understanding of drug mode of action in the related kinetoplastid parasite Trypanosoma brucei. Therefore, we screened our genome-scale T. brucei RNA interference (RNAi) library against the current antileishmanial drugs sodium stibogluconate (antimonial), paromomycin, miltefosine, and amphotericin B. Identification of T. brucei orthologues of the known Leishmania antimonial and miltefosine plasma membrane transporters effectively validated our approach, while a cohort of 42 novel drug efficacy determinants provides new insights and serves as a resource. Follow-up analyses revealed the antimonial selectivity of the aquaglyceroporin TbAQP3. A lysosomal major facilitator superfamily transporter contributes to paromomycin-aminoglycoside efficacy. The vesicle-associated membrane protein TbVAMP7B and a flippase contribute to amphotericin B and miltefosine action and are potential cross-resistance determinants. Finally, multiple phospholipid-transporting flippases, including the T. brucei orthologue of the Leishmania miltefosine transporter, a putative β-subunit/CDC50 cofactor, and additional membrane-associated hits, affect amphotericin B efficacy, providing new insights into mechanisms of drug uptake and action. The findings from this orthology-based chemogenomic profiling approach substantially advance our understanding of antileishmanial drug action and potential resistance mechanisms and should facilitate the development of improved therapies as well as surveillance for drug-resistant parasites.
Collapse
|
17
|
Anti-Trypanosomal and Antimalarial Properties of Tetralone Derivatives and Structurally Related Benzocycloalkanones. ACTA ACUST UNITED AC 2019; 55:medicina55050206. [PMID: 31137665 PMCID: PMC6572618 DOI: 10.3390/medicina55050206] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 02/22/2019] [Accepted: 05/20/2019] [Indexed: 01/24/2023]
Abstract
Background and objectives: Sleeping sickness and malaria alike are insect-borne protozoan diseases that share overlapping endemic areas in sub-Saharan Africa. The causative agent for malaria has developed resistance against all currently deployed anti-malarial agents. In the case of sleeping sickness, the currently deployed therapeutic options are limited in efficacy and activity spectra, and there are very few drug candidates in the development pipeline. Thus, there is a need to search for new drug molecules with a novel mode of actions. Materials and Methods: In the current study, an in vitro screening of a library of tetralone derivatives and related benzocycloalkanones was effected against T. b. brucei and P. falciparum. Results: Several hits with low micromolar activity (0.4–8 µM) against T. b. brucei were identified. Conclusions: The identified hits have a low molecular weight (<280 Da), a low total polar surface area (<50 Ų), and a defined structure activity relationship, which all make them potential starting points for further hit optimization studies.
Collapse
|
18
|
Pawar H, Puri M, Fischer Weinberger R, Madhubala R, Zilberstein D. The arginine sensing and transport binding sites are distinct in the human pathogen Leishmania. PLoS Negl Trop Dis 2019; 13:e0007304. [PMID: 31017889 PMCID: PMC6502434 DOI: 10.1371/journal.pntd.0007304] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 05/06/2019] [Accepted: 03/14/2019] [Indexed: 01/08/2023] Open
Abstract
The intracellular protozoan parasite Leishmania donovani causes human visceral leishmaniasis. Intracellular L. donovani that proliferate inside macrophage phagolysosomes compete with the host for arginine, creating a situation that endangers parasite survival. Parasites have a sensor that upon arginine deficiency activates an Arginine Deprivation Response (ADR). L. donovani transport arginine via a high-affinity transporter (LdAAP3) that is rapidly up-regulated by ADR in intracellular amastigotes. To date, the sensor and its ligand have not been identified. Here, we show that the conserved amidino group at the distal cap of the arginine side chain is the ligand that activates ADR, in both promastigotes and intracellular amastigotes, and that arginine sensing and transport binding sites are distinct in L. donovani. Finally, upon addition of arginine and analogues to deprived cells, the amidino ligand activates rapid degradation of LdAAP3. This study provides the first identification of an intra-molecular ligand of a sensor that acts during infection. Leishmania donovani, the causative agent of visceral leishmaniasis, leads a digenetic life cycle as a flagellated promastigote in the vector sandfly and aflagellated amastigote within phagolysosomes of infected macrophages. Arginine is an essential amino acid for Leishmania which possesses a high specificity arginine transporter (LdAAP3), a protein that imports the amino acid into parasite cells. Arginine is primarily utilized in de novo protein synthesis and for biosynthesis of trypanothione via the polyamine pathway. It was previously reported by our group that L. donovani senses lack of arginine in the surrounding micro environment and activates a unique arginine deprivation response (ADR) pathway, thus upregulating the expression of LdAAP3 as well as other transporters. In the present study, we identified the region on the arginine molecule which is the ligand that activates ADR. We show that the conserved amidino group at the distal cap of the arginine side chain is the ligand that activates/suppresses ADR. Using arginine analogues that contain this group we observed that arginine sensing and transport are distinct in L. donovani, both in axenic promastigotes and intracellular amastigotes. Additionally, the arginine sensor responds to both arginine starvation and sufficiency.
Collapse
Affiliation(s)
- Harsh Pawar
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Madhu Puri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Rentala Madhubala
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Dan Zilberstein
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
- * E-mail:
| |
Collapse
|
19
|
Landfear SM. Protean permeases: Diverse roles for membrane transport proteins in kinetoplastid protozoa. Mol Biochem Parasitol 2018; 227:39-46. [PMID: 30590069 DOI: 10.1016/j.molbiopara.2018.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/13/2018] [Accepted: 12/19/2018] [Indexed: 11/26/2022]
Abstract
Kinetoplastid parasites such as Trypanosoma brucei, Trypanosoma cruzi, and Leishmania species rely upon their insect and vertebrate hosts to provide a plethora of nutrients throughout their life cycles. Nutrients and ions critical for parasite survival are taken up across the parasite plasma membrane by transporters and channels, polytopic membrane proteins that provide substrate-specific pores across the hydrophobic barrier. However, transporters and channels serve a wide range of biological functions beyond uptake of nutrients. This article highlights the diversity of activities that these integral membrane proteins serve and underscores the emerging complexity of their functions.
Collapse
Affiliation(s)
- Scott M Landfear
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR, 97239, USA.
| |
Collapse
|
20
|
Helmstetter F, Arnold P, Höger B, Petersen LM, Beitz E. Formate-nitrite transporters carrying nonprotonatable amide amino acids instead of a central histidine maintain pH-dependent transport. J Biol Chem 2018; 294:623-631. [PMID: 30455351 DOI: 10.1074/jbc.ra118.006340] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/09/2018] [Indexed: 01/25/2023] Open
Abstract
Microbial formate-nitrite transporter-type proteins (FNT) exhibit dual transport functionality. At neutral pH, electrogenic anion currents are detectable, whereas upon acidification transport of the neutral, protonated monoacid predominates. Physiologically, FNT-mediated proton co-transport is vital when monocarboxylic acid products of the energy metabolism, such as l-lactate, are released from the cell. Accordingly, Plasmodium falciparum malaria parasites can be killed by small-molecule inhibitors of PfFNT. Two opposing hypotheses on the site of substrate protonation are plausible. The proton relay mechanism postulates proton transfer from a highly conserved histidine centrally positioned in the transport path. The dielectric slide mechanism assumes decreasing acidity of substrates entering the lipophilic vestibules and protonation via the bulk water. Here, we defined the transport mechanism of the FNT from the amoebiasis parasite Entamoeba histolytica, EhFNT, and also show that BtFdhC from Bacillus thuringiensis is a functional formate transporter. Both FNTs carry a nonprotonatable amide amino acid, asparagine or glutamine, respectively, at the central histidine position. Despite having a nonprotonatable residue, EhFNT displayed the same substrate selectivity for larger monocarboxylates including l-lactate, a low substrate affinity as is typical for FNTs, and, strikingly, proton motive force-dependent transport as observed for PfFNT harboring a central histidine. These results argue against a proton relay mechanism, indicating that substrate protonation must occur outside of the central histidine region, most likely in the vestibules. Furthermore, EhFNT is the sole annotated FNT in the Entamoeba genome suggesting that it could be a putative new drug target with similar utility as that of the malarial PfFNT.
Collapse
Affiliation(s)
| | - Philipp Arnold
- the Anatomical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Bastian Höger
- From the Department of Pharmaceutical and Medicinal Chemistry, and
| | | | - Eric Beitz
- From the Department of Pharmaceutical and Medicinal Chemistry, and
| |
Collapse
|
21
|
Uzcátegui NL, Figarella K, Segnini A, Marsiccobetre S, Lang F, Beitz E, Rodríguez-Acosta A, Bertl A. Trypanosoma brucei aquaglyceroporins mediate the transport of metabolic end-products: Methylglyoxal, D-lactate, L-lactate and acetate. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2252-2261. [DOI: 10.1016/j.bbamem.2018.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/26/2018] [Accepted: 09/10/2018] [Indexed: 10/28/2022]
|
22
|
Thomas JA, Baker N, Hutchinson S, Dominicus C, Trenaman A, Glover L, Alsford S, Horn D. Insights into antitrypanosomal drug mode-of-action from cytology-based profiling. PLoS Negl Trop Dis 2018; 12:e0006980. [PMID: 30475806 PMCID: PMC6283605 DOI: 10.1371/journal.pntd.0006980] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 12/06/2018] [Accepted: 11/07/2018] [Indexed: 12/31/2022] Open
Abstract
Chemotherapy continues to have a major impact on reducing the burden of disease caused by trypanosomatids. Unfortunately though, the mode-of-action (MoA) of antitrypanosomal drugs typically remains unclear or only partially characterised. This is the case for four of five current drugs used to treat Human African Trypanosomiasis (HAT); eflornithine is a specific inhibitor of ornithine decarboxylase. Here, we used a panel of T. brucei cellular assays to probe the MoA of the current HAT drugs. The assays included DNA-staining followed by microscopy and quantitative image analysis, or flow cytometry; terminal dUTP nick end labelling to monitor mitochondrial (kinetoplast) DNA replication; antibody-based detection of sites of nuclear DNA damage; and fluorescent dye-staining of mitochondria or lysosomes. We found that melarsoprol inhibited mitosis; nifurtimox reduced mitochondrial protein abundance; pentamidine triggered progressive loss of kinetoplast DNA and disruption of mitochondrial membrane potential; and suramin inhibited cytokinesis. Thus, current antitrypanosomal drugs perturb distinct and specific cellular compartments, structures or cell cycle phases. Further exploiting the findings, we show that putative mitogen-activated protein-kinases contribute to the melarsoprol-induced mitotic defect, reminiscent of the mitotic arrest associated signalling cascade triggered by arsenicals in mammalian cells, used to treat leukaemia. Thus, cytology-based profiling can rapidly yield novel insight into antitrypanosomal drug MoA.
Collapse
Affiliation(s)
- James A. Thomas
- London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Nicola Baker
- The Centre for Immunology and Infection, University of York, Heslington, York, United Kingdom
| | | | | | - Anna Trenaman
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Sam Alsford
- London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - David Horn
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| |
Collapse
|
23
|
Venkatesh D, Zhang N, Zoltner M, del Pino RC, Field MC. Evolution of protein trafficking in kinetoplastid parasites: Complexity and pathogenesis. Traffic 2018; 19:803-812. [DOI: 10.1111/tra.12601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/24/2018] [Accepted: 06/25/2018] [Indexed: 12/31/2022]
Affiliation(s)
| | - Ning Zhang
- School of Life Sciences; University of Dundee; Dundee UK
| | - Martin Zoltner
- School of Life Sciences; University of Dundee; Dundee UK
| | | | - Mark C. Field
- School of Life Sciences; University of Dundee; Dundee UK
| |
Collapse
|
24
|
Melarsoprol Resistance in African Trypanosomiasis. Trends Parasitol 2018; 34:481-492. [DOI: 10.1016/j.pt.2018.04.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 01/06/2023]
|
25
|
Rico E, Jeacock L, Kovářová J, Horn D. Inducible high-efficiency CRISPR-Cas9-targeted gene editing and precision base editing in African trypanosomes. Sci Rep 2018; 8:7960. [PMID: 29785042 PMCID: PMC5962531 DOI: 10.1038/s41598-018-26303-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/09/2018] [Indexed: 12/21/2022] Open
Abstract
The Cas9 endonuclease can be programmed by guide RNA to introduce sequence-specific breaks in genomic DNA. Thus, Cas9-based approaches present a range of novel options for genome manipulation and precision editing. African trypanosomes are parasites that cause lethal human and animal diseases. They also serve as models for studies on eukaryotic biology, including 'divergent' biology. Genome modification, exploiting the native homologous recombination machinery, has been important for studies on trypanosomes but often requires multiple rounds of transfection using selectable markers that integrate at low efficiency. We report a system for delivering tetracycline inducible Cas9 and guide RNA to Trypanosoma brucei. In these cells, targeted DNA cleavage and gene disruption can be achieved at close to 100% efficiency without further selection. Disruption of aquaglyceroporin (AQP2) or amino acid transporter genes confers resistance to the clinical drugs pentamidine or eflornithine, respectively, providing simple and robust assays for editing efficiency. We also use the new system for homology-directed, precision base editing; a single-stranded oligodeoxyribonucleotide repair template was delivered to introduce a single AQP2 - T791G/L264R mutation in this case. The technology we describe now enables a range of novel programmed genome-editing approaches in T. brucei that would benefit from temporal control, high-efficiency and precision.
Collapse
Affiliation(s)
- Eva Rico
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Laura Jeacock
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Julie Kovářová
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - David Horn
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK.
| |
Collapse
|
26
|
Gupta A, Sankararamakrishnan R. dbSWEET: An Integrated Resource for SWEET Superfamily to Understand, Analyze and Predict the Function of Sugar Transporters in Prokaryotes and Eukaryotes. J Mol Biol 2018; 430:2203-2211. [PMID: 29665371 DOI: 10.1016/j.jmb.2018.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 04/04/2018] [Accepted: 04/11/2018] [Indexed: 12/16/2022]
Abstract
SWEET (Sweet Will Eventually be Exported Transporter) proteins have been recently discovered and form one of the three major families of sugar transporters. Homologs of SWEET are found in both prokaryotes and eukaryotes. Bacterial SWEET homologs have three transmembrane segments forming a triple-helical bundle and the functional form is dimers. Eukaryotic SWEETs have seven transmembrane helical segments forming two triple-helical bundles with a linker helix. Members of SWEET homologs have been shown to be involved in several important physiological processes in plants. However, not much is known regarding the biological significance of SWEET homologs in prokaryotes and in mammals. We have collected more than 2000 SWEET homologs from both prokaryotes and eukaryotes. For each homolog, we have modeled three different conformational states representing outward open, inward open and occluded states. We have provided details regarding substrate-interacting residues and residues forming the selectivity filter for each SWEET homolog. Several search and analysis options are available. The users can generate a phylogenetic tree and structure-based sequence alignment for selected set of sequences. With no metazoan SWEETs functionally characterized, the features observed in the selectivity filter residues can be used to predict the potential substrates that are likely to be transported across the metazoan SWEETs. We believe that this database will help the researchers to design mutational experiments and simulation studies that will aid to advance our understanding of the physiological role of SWEET homologs. This database is freely available to the scientific community at http://bioinfo.iitk.ac.in/bioinfo/dbSWEET/Home.
Collapse
Affiliation(s)
- Ankita Gupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | | |
Collapse
|
27
|
Meier A, Erler H, Beitz E. Targeting Channels and Transporters in Protozoan Parasite Infections. Front Chem 2018; 6:88. [PMID: 29637069 PMCID: PMC5881087 DOI: 10.3389/fchem.2018.00088] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 03/12/2018] [Indexed: 12/25/2022] Open
Abstract
Infectious diseases caused by pathogenic protozoa are among the most significant causes of death in humans. Therapeutic options are scarce and massively challenged by the emergence of resistant parasite strains. Many of the current anti-parasite drugs target soluble enzymes, generate unspecific oxidative stress, or act by an unresolved mechanism within the parasite. In recent years, collections of drug-like compounds derived from large-scale phenotypic screenings, such as the malaria or pathogen box, have been made available to researchers free of charge boosting the identification of novel promising targets. Remarkably, several of the compound hits have been found to inhibit membrane proteins at the periphery of the parasites, i.e., channels and transporters for ions and metabolites. In this review, we will focus on the progress made on targeting channels and transporters at different levels and the potential for use against infections with apicomplexan parasites mainly Plasmodium spp. (malaria) and Toxoplasma gondii (toxoplasmosis), with kinetoplastids Trypanosoma brucei (sleeping sickness), Trypanosoma cruzi (Chagas disease), and Leishmania ssp. (leishmaniasis), and the amoeba Entamoeba histolytica (amoebiasis).
Collapse
Affiliation(s)
- Anna Meier
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Holger Erler
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| |
Collapse
|
28
|
Franco J, Scarone L, Comini MA. Drugs and Drug Resistance in African and American Trypanosomiasis. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2018. [DOI: 10.1016/bs.armc.2018.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
29
|
Schmidt RS, Macêdo JP, Steinmann ME, Salgado AG, Bütikofer P, Sigel E, Rentsch D, Mäser P. Transporters of Trypanosoma brucei-phylogeny, physiology, pharmacology. FEBS J 2017; 285:1012-1023. [PMID: 29063677 DOI: 10.1111/febs.14302] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/18/2017] [Accepted: 10/18/2017] [Indexed: 12/12/2022]
Abstract
Trypanosoma brucei comprise the causative agents of sleeping sickness, T. b. gambiense and T. b. rhodesiense, as well as the livestock-pathogenic T. b. brucei. The parasites are transmitted by the tsetse fly and occur exclusively in sub-Saharan Africa. T. brucei are not only lethal pathogens but have also become model organisms for molecular parasitology. We focus here on membrane transport proteins of T. brucei, their contribution to homeostasis and metabolism in the context of a parasitic lifestyle, and their pharmacological role as potential drug targets or routes of drug entry. Transporters and channels in the plasma membrane are attractive drug targets as they are accessible from the outside. Alternatively, they can be exploited to selectively deliver harmful substances into the trypanosome's interior. Both approaches require the targeted transporter to be essential: in the first case to kill the trypanosome, in the second case to prevent drug resistance due to loss of the transporter. By combining functional and phylogenetic analyses, we were mining the T. brucei predicted proteome for transporters of pharmacological significance. Here, we review recent progress in the identification of transporters of lipid precursors, amino acid permeases and ion channels in T. brucei.
Collapse
Affiliation(s)
- Remo S Schmidt
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Juan P Macêdo
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Michael E Steinmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | | | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | - Erwin Sigel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| |
Collapse
|
30
|
Stijlemans B, De Baetselier P, Caljon G, Van Den Abbeele J, Van Ginderachter JA, Magez S. Nanobodies As Tools to Understand, Diagnose, and Treat African Trypanosomiasis. Front Immunol 2017; 8:724. [PMID: 28713367 PMCID: PMC5492476 DOI: 10.3389/fimmu.2017.00724] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 06/08/2017] [Indexed: 02/04/2023] Open
Abstract
African trypanosomes are strictly extracellular protozoan parasites that cause diseases in humans and livestock and significantly affect the economic development of sub-Saharan Africa. Due to an elaborate and efficient (vector)–parasite–host interplay, required to complete their life cycle/transmission, trypanosomes have evolved efficient immune escape mechanisms that manipulate the entire host immune response. So far, not a single field applicable vaccine exists, and chemotherapy is the only strategy available to treat the disease. Current therapies, however, exhibit high drug toxicity and an increased drug resistance is being reported. In addition, diagnosis is often hampered due to the inadequacy of current diagnostic procedures. In the context of tackling the shortcomings of current treatment and diagnostic approaches, nanobodies (Nbs, derived from the heavy chain-only antibodies of camels and llamas) might represent unmet advantages compared to conventional tools. Indeed, the combination of their small size, high stability, high affinity, and specificity for their target and tailorability represents a unique advantage, which is reflected by their broad use in basic and clinical research to date. In this article, we will review and discuss (i) diagnostic and therapeutic applications of Nbs that are being evaluated in the context of African trypanosomiasis, (ii) summarize new strategies that are being developed to optimize their potency for advancing their use, and (iii) document on unexpected properties of Nbs, such as inherent trypanolytic activities, that besides opening new therapeutic avenues, might offer new insight in hidden biological activities of conventional antibodies.
Collapse
Affiliation(s)
- Benoit Stijlemans
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Lab, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Patrick De Baetselier
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Lab, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Guy Caljon
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp (UA), Antwerp, Belgium
| | - Jan Van Den Abbeele
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium
| | - Jo A Van Ginderachter
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Myeloid Cell Immunology Lab, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
| |
Collapse
|
31
|
Jeacock L, Baker N, Wiedemar N, Mäser P, Horn D. Aquaglyceroporin-null trypanosomes display glycerol transport defects and respiratory-inhibitor sensitivity. PLoS Pathog 2017; 13:e1006307. [PMID: 28358927 PMCID: PMC5388498 DOI: 10.1371/journal.ppat.1006307] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 04/11/2017] [Accepted: 03/22/2017] [Indexed: 11/19/2022] Open
Abstract
Aquaglyceroporins (AQPs) transport water and glycerol and play important roles in drug-uptake in pathogenic trypanosomatids. For example, AQP2 in the human-infectious African trypanosome, Trypanosoma brucei gambiense, is responsible for melarsoprol and pentamidine-uptake, and melarsoprol treatment-failure has been found to be due to AQP2-defects in these parasites. To further probe the roles of these transporters, we assembled a T. b. brucei strain lacking all three AQP-genes. Triple-null aqp1-2-3 T. b. brucei displayed only a very moderate growth defect in vitro, established infections in mice and recovered effectively from hypotonic-shock. The aqp1-2-3 trypanosomes did, however, display glycerol uptake and efflux defects. They failed to accumulate glycerol or to utilise glycerol as a carbon-source and displayed increased sensitivity to salicylhydroxamic acid (SHAM), octyl gallate or propyl gallate; these inhibitors of trypanosome alternative oxidase (TAO) can increase intracellular glycerol to toxic levels. Notably, disruption of AQP2 alone generated cells with glycerol transport defects. Consistent with these findings, AQP2-defective, melarsoprol-resistant clinical isolates were sensitive to the TAO inhibitors, SHAM, propyl gallate and ascofuranone, relative to melarsoprol-sensitive reference strains. We conclude that African trypanosome AQPs are dispensable for viability and osmoregulation but they make important contributions to drug-uptake, glycerol-transport and respiratory-inhibitor sensitivity. We also discuss how the AQP-dependent inverse sensitivity to melarsoprol and respiratory inhibitors described here might be exploited.
Collapse
Affiliation(s)
- Laura Jeacock
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Nicola Baker
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Natalie Wiedemar
- Parasite Chemotherapy Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Pascal Mäser
- Parasite Chemotherapy Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - David Horn
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| |
Collapse
|
32
|
Wiechert M, Beitz E. Mechanism of formate-nitrite transporters by dielectric shift of substrate acidity. EMBO J 2017; 36:949-958. [PMID: 28250043 DOI: 10.15252/embj.201695776] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 11/09/2022] Open
Abstract
Bacterial formate-nitrite transporters (FNTs) regulate the metabolic flow of small, weak mono-acids. Recently, the eukaryotic PfFNT was identified as the malaria parasite's lactate transporter and novel drug target. Despite crystal data, central mechanisms of FNT gating and transport remained unclear. Here, we show elucidation of the FNT transport mechanism by single-step substrate protonation involving an invariant lysine in the periplasmic vestibule. Opposing earlier gating hypotheses and electrophysiology reports, quantification of total uptake by radiolabeled substrate indicates a permanently open conformation of the bacterial formate transporter, FocA, irrespective of the pH Site-directed mutagenesis, heavy water effects, mathematical modeling, and simulations of solvation imply a general, proton motive force-driven FNT transport mechanism: Electrostatic attraction of the acid anion into a hydrophobic vestibule decreases substrate acidity and facilitates protonation by the bulk solvent. We define substrate neutralization by proton transfer for transport via a hydrophobic transport path as a general theme of the Amt/Mep/Rh ammonium and formate-nitrite transporters.
Collapse
Affiliation(s)
- Marie Wiechert
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| |
Collapse
|
33
|
Field MC, Horn D, Fairlamb AH, Ferguson MAJ, Gray DW, Read KD, De Rycker M, Torrie LS, Wyatt PG, Wyllie S, Gilbert IH. Anti-trypanosomatid drug discovery: an ongoing challenge and a continuing need. Nat Rev Microbiol 2017; 15:217-231. [PMID: 28239154 PMCID: PMC5582623 DOI: 10.1038/nrmicro.2016.193] [Citation(s) in RCA: 263] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The WHO recognizes human African trypanosomiasis, Chagas disease and the leishmaniases as neglected tropical diseases. These diseases are caused by parasitic trypanosomatids and range in severity from mild and self-curing to near invariably fatal. Public health advances have substantially decreased the effect of these diseases in recent decades but alone will not eliminate them. In this Review, we discuss why new drugs against trypanosomatids are required, approaches that are under investigation to develop new drugs and why the drug discovery pipeline remains essentially unfilled. In addition, we consider the important challenges to drug discovery strategies and the new technologies that can address them. The combination of new drugs, new technologies and public health initiatives is essential for the management, and hopefully eventual elimination, of trypanosomatid diseases from the human population.
Collapse
Affiliation(s)
- Mark C Field
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - David Horn
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Alan H Fairlamb
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Michael A J Ferguson
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - David W Gray
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Kevin D Read
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Manu De Rycker
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Leah S Torrie
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Paul G Wyatt
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Susan Wyllie
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| | - Ian H Gilbert
- Wellcome Centre for Anti-Infectives Research, University of Dundee, Dundee DD1 5EH, UK
| |
Collapse
|
34
|
Marsiccobetre S, Rodríguez-Acosta A, Lang F, Figarella K, Uzcátegui NL. Aquaglyceroporins Are the Entry Pathway of Boric Acid in Trypanosoma brucei. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:679-685. [PMID: 28087364 DOI: 10.1016/j.bbamem.2017.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 01/03/2017] [Accepted: 01/07/2017] [Indexed: 11/17/2022]
Abstract
The boron element possesses a range of different effects on living beings. It is essential to beneficial at low concentrations, but toxic at excessive concentrations. Recently, some boron-based compounds have been identified as promising molecules against Trypanosoma brucei, the causative agent of sleeping sickness. However, until now, the boron metabolism and its access route into the parasite remained elusive. The present study addressed the permeability of T. brucei aquaglyceroporins (TbAQPs) for boric acid, the main natural boron species. To this end, the three TbAQPs were expressed in Saccharomyces cerevisiae and Xenopus laevis oocytes. Our findings in both expression systems showed that all three TbAQPs are permeable for boric acid. Especially TbAQP2 is highly permeable for this compound, displaying one of the highest conductances reported for a solute in these channels. Additionally, T. brucei aquaglyceroporin activities were sensitive to pH. Taken together, these results establish that TbAQPs are channels for boric acid and are highly efficient entry pathways for boron into the parasite. Our findings stress the importance of studying the physiological functions of boron and their derivatives in T. brucei, as well as the pharmacological implications of their uptake by trypanosome aquaglyceroporins.
Collapse
Affiliation(s)
- Sabrina Marsiccobetre
- Laboratory of Immunochemistry and Ultrastructure, Institute of Anatomy, Central University of Venezuela, Caracas, Venezuela
| | - Alexis Rodríguez-Acosta
- Laboratory of Immunochemistry and Ultrastructure, Institute of Anatomy, Central University of Venezuela, Caracas, Venezuela
| | - Florian Lang
- Department of Physiology I, University of Tubingen, Tubingen, Germany
| | - Katherine Figarella
- Laboratory of Immunochemistry and Ultrastructure, Institute of Anatomy, Central University of Venezuela, Caracas, Venezuela.
| | - Néstor L Uzcátegui
- Laboratory of Immunochemistry and Ultrastructure, Institute of Anatomy, Central University of Venezuela, Caracas, Venezuela; Department of Physiology I, University of Tubingen, Tubingen, Germany.
| |
Collapse
|
35
|
Antileishmanial Mechanism of Diamidines Involves Targeting Kinetoplasts. Antimicrob Agents Chemother 2016; 60:6828-6836. [PMID: 27600039 DOI: 10.1128/aac.01129-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/28/2016] [Indexed: 02/08/2023] Open
Abstract
Leishmaniasis is a disease caused by pathogenic Leishmania parasites; current treatments are toxic and expensive, and drug resistance has emerged. While pentamidine, a diamidine-type compound, is one of the treatments, its antileishmanial mechanism of action has not been investigated in depth. Here we tested several diamidines, including pentamidine and its analog DB75, against Leishmania donovani and elucidated their antileishmanial mechanisms. We identified three promising new antileishmanial diamidine compounds with 50% effective concentrations (EC50s) of 3.2, 3.4, and 4.5 μM, while pentamidine and DB75 exhibited EC50s of 1.46 and 20 μM, respectively. The most potent antileishmanial inhibitor, compound 1, showed strong DNA binding properties, with a shift in the melting temperature (ΔTm) of 24.2°C, whereas pentamidine had a ΔTm value of 2.1°C, and DB75 had a ΔTm value of 7.7°C. Additionally, DB75 localized in L. donovani kinetoplast DNA (kDNA) and mitochondria but not in nuclear DNA (nDNA). For 2 new diamidines, strong localization signals were observed in kDNA at 1 μM, and at higher concentrations, the signals also appeared in nuclei. All tested diamidines showed selective and dose-dependent inhibition of kDNA, but not nDNA, replication, likely by inhibiting L. donovani topoisomerase IB. Overall, these results suggest that diamidine antileishmanial compounds exert activity by accumulating toward and blocking replication of parasite kDNA.
Collapse
|
36
|
Abstract
Pathogenic animal trypanosomes affecting livestock have represented a major constraint to agricultural development in Africa for centuries, and their negative economic impact is increasing in South America and Asia. Chemotherapy and chemoprophylaxis represent the main means of control. However, research into new trypanocides has remained inadequate for decades, leading to a situation where the few compounds available are losing efficacy due to the emergence of drug-resistant parasites. In this review, we provide a comprehensive overview of the current options available for the treatment and prophylaxis of the animal trypanosomiases, with a special focus on the problem of resistance. The key issues surrounding the main economically important animal trypanosome species and the diseases they cause are also presented. As new investment becomes available to develop improved tools to control the animal trypanosomiases, we stress that efforts should be directed towards a better understanding of the biology of the relevant parasite species and strains, to identify new drug targets and interrogate resistance mechanisms.
Collapse
|
37
|
Zoltner M, Horn D, de Koning HP, Field MC. Exploiting the Achilles' heel of membrane trafficking in trypanosomes. Curr Opin Microbiol 2016; 34:97-103. [PMID: 27614711 PMCID: PMC5176092 DOI: 10.1016/j.mib.2016.08.005] [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: 05/27/2016] [Revised: 08/16/2016] [Accepted: 08/24/2016] [Indexed: 11/25/2022]
Abstract
Pathogenic protozoa are evolutionarily highly divergent from their metazoan hosts, reflected in many aspects of their biology. One particularly important parasite taxon is the trypanosomatids. Multiple transmission modes, distinct life cycles and exploitation of many host species attests to great prowess as parasites, and adaptability for efficient, chronic infection. Genome sequencing has begun uncovering how trypanosomatids are well suited to parasitism, and recent genetic screening and cell biology are revealing new aspects of how to control these organisms and prevent disease. Importantly, several lines of evidence suggest that membrane transport processes are central for the sensitivity towards several frontline drugs.
Collapse
Affiliation(s)
- Martin Zoltner
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - David Horn
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, Scotland, UK
| | - Mark C Field
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.
| |
Collapse
|
38
|
Abstract
Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies.
Collapse
Affiliation(s)
- Alan H. Fairlamb
- Dundee Drug Discovery Unit, Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Neil A. R. Gow
- Aberdeen Fungal Group, Wellcome Trust Strategic Award in Medical Mycology and Fungal Immunology, School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Keith R. Matthews
- Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Andrew P. Waters
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical and Veterinary Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| |
Collapse
|
39
|
Foscolos AS, Papanastasiou I, Foscolos GB, Tsotinis A, Kellici TF, Mavromoustakos T, Taylor MC, Kelly JM. New hydrazones of 5-nitro-2-furaldehyde with adamantanealkanohydrazides: synthesis and in vitro trypanocidal activity. MEDCHEMCOMM 2016. [DOI: 10.1039/c6md00035e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A range of hydrazones of 5-nitro-2-furaldehyde with adamantane alkanohydrazides was synthesized and their trypanocidal activity was evaluated.
Collapse
Affiliation(s)
- Angeliki-Sofia Foscolos
- School of Health Sciences
- Faculty of Pharmacy
- Department of Pharmaceutical Chemistry
- National and Kapodistrian University of Athens
- 15784 Athens
| | - Ioannis Papanastasiou
- School of Health Sciences
- Faculty of Pharmacy
- Department of Pharmaceutical Chemistry
- National and Kapodistrian University of Athens
- 15784 Athens
| | - George B. Foscolos
- School of Health Sciences
- Faculty of Pharmacy
- Department of Pharmaceutical Chemistry
- National and Kapodistrian University of Athens
- 15784 Athens
| | - Andrew Tsotinis
- School of Health Sciences
- Faculty of Pharmacy
- Department of Pharmaceutical Chemistry
- National and Kapodistrian University of Athens
- 15784 Athens
| | - Tahsin F. Kellici
- Faculty of Chemistry
- Department of Organic Chemistry
- University of Athens
- 15771 Athens
- Greece
| | - Thomas Mavromoustakos
- Faculty of Chemistry
- Department of Organic Chemistry
- University of Athens
- 15771 Athens
- Greece
| | - Martin C. Taylor
- Department of Pathogen Molecular Biology
- London School of Hygiene and Tropical Medicine
- London WC1 E7HT
- UK
| | - John M. Kelly
- Department of Pathogen Molecular Biology
- London School of Hygiene and Tropical Medicine
- London WC1 E7HT
- UK
| |
Collapse
|