1
|
Liu H, Xu Y, Sun Y, Wu H, Hou J. Tissue-specific toxic effects of nano-copper on zebrafish. ENVIRONMENTAL RESEARCH 2024; 242:117717. [PMID: 37993046 DOI: 10.1016/j.envres.2023.117717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 09/23/2023] [Accepted: 11/15/2023] [Indexed: 11/24/2023]
Abstract
Understanding the behavior and potential toxicity of copper nanoparticles (nano-Cu) in the aquatic environment is a primary way to assess their environmental risks. In this study, RNA-seq was performed on three different tissues (gills, intestines, and muscles) of zebrafish exposed to nano-Cu, to explore the potential toxic mechanism of nano-Cu on zebrafish. The results indicated that the toxic mechanism of nano-Cu on zebrafish was tissue-specific. Nano-Cu enables the CB1 receptor of the presynaptic membrane of gill cells to affect short-term synaptic plasticity or long-term synaptic changes (ECB-LTD) through DSI and DSE, causing dysfunction of intercellular signal transmission. Imbalance of de novo synthesis of UMP in intestinal cells and its transformation to UDP, UTP, uridine, and uracil, resulted in many functions involved in the pyrimidine metabolic pathway being blocked. Meanwhile, the toxicity of nano-Cu caused abnormal expression of RAD51 gene in muscle cells, which affects the repair of damaged DNA through Fanconi anemia and homologous recombination pathway, thus causing cell cycle disorder. These results provide insights for us to better understand the differences in toxicity of nano-Cu on zebrafish tissues and are helpful for a comprehensive assessment of nano-Cu's effects on aquatic organisms.
Collapse
Affiliation(s)
- Haiqiang Liu
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China; College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China; Key Laboratory of Mass Spectrometry Imaging and Metabolomics (State Ethnic Affairs Commission), Centre for Imaging & Systems Biology, Minzu University of China, Beijing, 100081, China
| | - Yanli Xu
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China
| | - Yuqiong Sun
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China
| | - Haodi Wu
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China
| | - Jing Hou
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China.
| |
Collapse
|
2
|
Das A, Liu T, Li H, Husain S. The RNA-binding protein RBP42 regulates cellular energy metabolism in mammalian-infective Trypanosoma brucei. mSphere 2023; 8:e0027323. [PMID: 37581443 PMCID: PMC10654194 DOI: 10.1128/msphere.00273-23] [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: 05/16/2023] [Accepted: 06/05/2023] [Indexed: 08/16/2023] Open
Abstract
RNA-binding proteins (RBPs) are key players in coordinated post-transcriptional regulation of functionally related genes, defined as RNA regulons. RNA regulons play particularly critical roles in parasitic trypanosomes, which exhibit unregulated co-transcription of long unrelated gene arrays. In this report, we present a systematic analysis of an essential RBP, RBP42, in the mammalian-infective bloodstream form of African trypanosome and show that RBP42 is a key regulator of parasite's central carbon and energy metabolism. Using individual-nucleotide resolution UV cross-linking and immunoprecipitation to identify genome-wide RBP42-RNA interactions, we show that RBP42 preferentially binds within the coding region of mRNAs encoding core metabolic enzymes. Global quantitative transcriptomic and proteomic analyses reveal that loss of RBP42 reduces the abundance of target mRNA-encoded proteins, but not target mRNA, suggesting a positive translational regulatory role of RBP42. Significant changes in central carbon metabolic intermediates, following loss of RBP42, further support its critical role in cellular energy metabolism. Trypanosoma brucei infection, transmitted through the bite of blood-feeding tsetse flies, causes deadly diseases in humans and livestock. This disease, if left untreated, is almost always fatal. Existing therapies are toxic and difficult to administer. During T. brucei's lifecycle in two different host environments, the parasite progresses through distinctive life stages with major morphological and metabolic changes, requiring precise alteration of parasite gene expression program. In the absence of regulated transcription, post-transcriptional processes mediated by RNA-binding proteins play critical roles in T. brucei gene regulation. In this study, we show that the RNA-binding protein RBP42 plays crucial roles in cellular energy metabolic regulation of this important human pathogen. Metabolic dysregulation observed in RBP42 knockdown cells offers a breadth of potential interest to researchers studying parasite biology and can also impact research in general eukaryotic biology.
Collapse
Affiliation(s)
- Anish Das
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers-New Jersey Medical School, Newark, New Jersey, USA
| | - Tong Liu
- Center for Advanced Proteomics Research, Rutgers-New Jersey Medical School, Newark, New Jersey, USA
| | - Hong Li
- Center for Advanced Proteomics Research, Rutgers-New Jersey Medical School, Newark, New Jersey, USA
| | - Seema Husain
- Genomics Center, Rutgers-New Jersey Medical School, Newark, New Jersey, USA
| |
Collapse
|
3
|
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
|
4
|
da Silva W, Ribeiro IC, Agripino JDM, da Silva VHF, de Souza LÂ, Oliveira TA, Bressan GC, Vasconcellos RDS, Dumas C, Pelletier J, Sévigny J, Papadopoulou B, Fietto JLR. Leishmania infantum NTPDase1 and NTPDase2 play an important role in infection and nitric oxide production in macrophages. Acta Trop 2022; 237:106732. [DOI: 10.1016/j.actatropica.2022.106732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/16/2022]
|
5
|
Campagnaro GD. Purine Transporters as Efficient Carriers for Anti-kinetoplastid Molecules: 3'-Deoxytubercidin versus Trypanosomes. ACS Infect Dis 2022; 8:1727-1730. [PMID: 35925865 DOI: 10.1021/acsinfecdis.2c00356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
After a growing interest in the function of purine transporters in protozoa during the 1990s and early 2000s, the area experienced a lull phase. Recently, however, the potential of tubercidin derivatives, particularly 3'-deoxytubercidin, to cure Trypanosoma brucei infection seems to have started a new wave of interest in the subject, with a large number of newly designed compounds and extensive in vitro testing against T. brucei, Trypanosoma cruzi, and Leishmania spp. Understanding the biochemical properties of purine transporters and using them as drug carriers seem to be emerging once again as a valuable tactic in the fight against neglected diseases.
Collapse
Affiliation(s)
- Gustavo Daniel Campagnaro
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, 14049-900 São Paulo, Brazil
| |
Collapse
|
6
|
Mesa JM, Comini MA, Dibello E, Gamenara D. Organocatalytic synthesis and anti‐trypanosomal activity evaluation of L‐pentofuranose‐mimetic iminosugars. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Juan Manuel Mesa
- Universidad de la Republica Uruguay Organic chemistry department Gral. Flores 2124 11800 Montevideo URUGUAY
| | - Marcelo Alberto Comini
- Institut Pasteur Montevideo Group Redox Biology of Trypanosomes Mataojo 2020 11400 Montevideo URUGUAY
| | - Estefania Dibello
- Universidad de la República Uruguay Departamento de Química Orgánica Gral. Flores 21 24 11800 Montevideo URUGUAY
| | - Daniela Gamenara
- Universidad de la Republica Facultad de Quimica Organic Chemistry Department Gral. Flores 2124 11800 Montevideo URUGUAY
| |
Collapse
|
7
|
Venturelli A, Tagliazucchi L, Lima C, Venuti F, Malpezzi G, Magoulas GE, Santarem N, Calogeropoulou T, Cordeiro-da-Silva A, Costi MP. Current Treatments to Control African Trypanosomiasis and One Health Perspective. Microorganisms 2022; 10:microorganisms10071298. [PMID: 35889018 PMCID: PMC9321528 DOI: 10.3390/microorganisms10071298] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/10/2022] [Accepted: 06/20/2022] [Indexed: 02/01/2023] Open
Abstract
Human African Trypanosomiasis (HAT, sleeping sickness) and Animal African Trypanosomiasis (AAT) are neglected tropical diseases generally caused by the same etiological agent, Trypanosoma brucei. Despite important advances in the reduction or disappearance of HAT cases, AAT represents a risky reservoir of the infections. There is a strong need to control AAT, as is claimed by the European Commission in a recent document on the reservation of antimicrobials for human use. Control of AAT is considered part of the One Health approach established by the FAO program against African Trypanosomiasis. Under the umbrella of the One Health concepts, in this work, by analyzing the pharmacological properties of the therapeutic options against Trypanosoma brucei spp., we underline the need for clearer and more defined guidelines in the employment of drugs designed for HAT and AAT. Essential requirements are addressed to meet the challenge of drug use and drug resistance development. This approach shall avoid inter-species cross-resistance phenomena and retain drugs therapeutic activity.
Collapse
Affiliation(s)
- Alberto Venturelli
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (A.V.); (L.T.); (F.V.); (G.M.)
| | - Lorenzo Tagliazucchi
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (A.V.); (L.T.); (F.V.); (G.M.)
- Doctorate School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Clara Lima
- Host-Parasite Interactions Group, Institute of Research and Innovation in Health, University of Porto, 4099-002 Porto, Portugal; (C.L.); (N.S.); (A.C.-d.-S.)
- Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4099-002 Porto, Portugal
| | - Federica Venuti
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (A.V.); (L.T.); (F.V.); (G.M.)
| | - Giulia Malpezzi
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (A.V.); (L.T.); (F.V.); (G.M.)
| | - George E. Magoulas
- Institute of Chemical Biology, National Hellenic Research Foundation, 11635 Athens, Greece; (G.E.M.); (T.C.)
| | - Nuno Santarem
- Host-Parasite Interactions Group, Institute of Research and Innovation in Health, University of Porto, 4099-002 Porto, Portugal; (C.L.); (N.S.); (A.C.-d.-S.)
- Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4099-002 Porto, Portugal
| | - Theodora Calogeropoulou
- Institute of Chemical Biology, National Hellenic Research Foundation, 11635 Athens, Greece; (G.E.M.); (T.C.)
| | - Anabela Cordeiro-da-Silva
- Host-Parasite Interactions Group, Institute of Research and Innovation in Health, University of Porto, 4099-002 Porto, Portugal; (C.L.); (N.S.); (A.C.-d.-S.)
- Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4099-002 Porto, Portugal
| | - Maria Paola Costi
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; (A.V.); (L.T.); (F.V.); (G.M.)
- Correspondence:
| |
Collapse
|
8
|
Inosine triphosphate pyrophosphatase from Trypanosoma brucei cleanses cytosolic pools from deaminated nucleotides. Sci Rep 2022; 12:6408. [PMID: 35436992 PMCID: PMC9016069 DOI: 10.1038/s41598-022-10149-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/04/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractInosine triphosphate pyrophosphatases (ITPases) are ubiquitous house-cleaning enzymes that specifically recognize deaminated purine nucleotides and catalyze their hydrolytic cleavage. In this work, we have characterized the Trypanosoma brucei ITPase ortholog (TbITPA). Recombinant TbITPA efficiently hydrolyzes (deoxy)ITP and XTP nucleotides into their respective monophosphate form. Immunolocalization analysis performed in bloodstream forms suggests that the primary role of TbITPA is the exclusion of deaminated purines from the cytosolic nucleoside triphosphate pools. Even though ITPA-knockout bloodstream parasites are viable, they are more sensitive to inhibition of IMP dehydrogenase with mycophenolic acid, likely due to an expansion of IMP, the ITP precursor. On the other hand, TbITPA can also hydrolyze the activated form of the antiviral ribavirin although in this case, the absence of ITPase activity in the cell confers protection against this nucleoside analog. This unexpected phenotype is dependant on purine availability and can be explained by the fact that ribavirin monophosphate, the reaction product generated by TbITPA, is a potent inhibitor of trypanosomal IMP dehydrogenase and GMP reductase. In summary, the present study constitutes the first report on a protozoan inosine triphosphate pyrophosphatase involved in the removal of harmful deaminated nucleotides from the cytosolic pool.
Collapse
|
9
|
Dello Iacono L, Di Pisa F, Mangani S. Crystal structure of the ternary complex of Leishmania major pteridine reductase 1 with the cofactor NADP +/NADPH and the substrate folic acid. Acta Crystallogr F Struct Biol Commun 2022; 78:170-176. [PMID: 35400669 PMCID: PMC8996148 DOI: 10.1107/s2053230x22002795] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/14/2022] [Indexed: 11/10/2022] Open
Abstract
Pteridine reductase 1 (PTR1) is a key enzyme of the folate pathway in protozoan parasites of the genera Leishmania and Trypanosoma and is a valuable drug target for tropical diseases. This enzyme is able to catalyze the NADPH-dependent reduction of both conjugated (folate) and unconjugated (biopterin) pterins to their tetrahydro forms, starting from oxidized- or dihydro-state substrates. The currently available X-ray structures of Leishmania major PTR1 (LmPTR1) show the enzyme in its unbound, unconjugated substrate-bound (with biopterin derivatives) and inhibitor-bound forms. However, no structure has yet been determined of LmPTR1 bound to a conjugated substrate. Here, the high-resolution crystal structure of LmPTR1 in complex with folic acid is presented and the intermolecular forces that drive the binding of the substrate in the catalytic pocket are described. By expanding the collection of LmPTR1 structures in complex with process intermediates, additional insights into the active-site rearrangements that occur during the catalytic process are provided. In contrast to previous structures with biopterin derivatives, a small but significant difference in the orientation of Asp181 and Tyr194 of the catalytic triad is found. This feature is shared by PTR1 from T. brucei (TbPTR1) in complex with the same substrate molecule and may be informative in deciphering the importance of such residues at the beginning of the catalytic process.
Collapse
Affiliation(s)
- Lucia Dello Iacono
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Flavio Di Pisa
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Stefano Mangani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| |
Collapse
|
10
|
Degano M. Structure, Oligomerization and Activity Modulation in N-Ribohydrolases. Int J Mol Sci 2022; 23:ijms23052576. [PMID: 35269719 PMCID: PMC8910321 DOI: 10.3390/ijms23052576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 12/15/2022] Open
Abstract
Enzymes catalyzing the hydrolysis of the N-glycosidic bond in nucleosides and other ribosides (N-ribohydrolases, NHs) with diverse substrate specificities are found in all kingdoms of life. While the overall NH fold is highly conserved, limited substitutions and insertions can account for differences in substrate selection, catalytic efficiency, and distinct structural features. The NH structural module is also employed in monomeric proteins devoid of enzymatic activity with different physiological roles. The homo-oligomeric quaternary structure of active NHs parallels the different catalytic strategies used by each isozyme, while providing a buttressing effect to maintain the active site geometry and allow the conformational changes required for catalysis. The unique features of the NH catalytic strategy and structure make these proteins attractive targets for diverse therapeutic goals in different diseases.
Collapse
Affiliation(s)
- Massimo Degano
- Biocrystallography Unit, Division of Immunology, Transplantation, and Infectious Diseases, IRCCS Scientific Institute San Raffaele, via Olgettina 60, 20132 Milano, Italy;
- Università Vita-Salute San Raffaele, via Olgettina 58, 20132 Milano, Italy
| |
Collapse
|
11
|
Miranda MR, Sayé M, Reigada C, Galceran F, Rengifo M, Maciel BJ, Digirolamo FA, Pereira CA. Revisiting trypanosomatid nucleoside diphosphate kinases. Mem Inst Oswaldo Cruz 2022; 116:e210339. [PMID: 35170678 PMCID: PMC8833001 DOI: 10.1590/0074-02760210339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/26/2021] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND An increasing amount of research has led to the positioning of nucleoside diphosphate kinases (NDPK/NDK) as key metabolic enzymes among all organisms. They contribute to the maintenance the intracellular di- and tri- phosphate nucleoside homeostasis, but they also are involved in widely diverse processes such as gene regulation, apoptosis, signal transduction and many other regulatory roles. OBJETIVE Examine in depth the NDPKs of trypanosomatid parasites responsible for devastating human diseases (e.g., Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp.) which deserve special attention. METHODS The earliest and latest advances in the topic were explored, focusing on trypanosomatid NDPK features, multifunctionality and suitability as molecular drug targets. FINDINGS Trypanosomatid NDPKs appear to play functions different from their host counterparts. Evidences indicate that they would perform key roles in the parasite metabolism such as nucleotide homeostasis, drug resistance, DNA damage responses and gene regulation, as well as host-parasite interactions, infection, virulence and immune evasion, placing them as attractive pharmacological targets. MAIN CONCLUSIONS NDPKs are very interesting multifunctional enzymes. In the present review, the potential of trypanosomatid NDPKs was highlighted, raising awareness of their value not only with respect to parasite biology but also as molecular targets.
Collapse
Affiliation(s)
- Mariana R Miranda
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina,+ Corresponding author: /
| | - Melisa Sayé
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Chantal Reigada
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Facundo Galceran
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Marcos Rengifo
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Belen J Maciel
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Fabio A Digirolamo
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Claudio A Pereira
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A Lanari, Buenos Aires, Argentina,Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas, Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| |
Collapse
|
12
|
Glockzin K, Meek TD, Katzfuss A. Characterization of adenine phosphoribosyltransferase (APRT) activity in Trypanosoma brucei brucei: Only one of the two isoforms is kinetically active. PLoS Negl Trop Dis 2022; 16:e0009926. [PMID: 35104286 PMCID: PMC8836349 DOI: 10.1371/journal.pntd.0009926] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 02/11/2022] [Accepted: 01/22/2022] [Indexed: 11/17/2022] Open
Abstract
Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a Neglected Tropical Disease endemic to 36 African countries, with approximately 70 million people currently at risk for infection. Current therapeutics are suboptimal due to toxicity, adverse side effects, and emerging resistance. Thus, both effective and affordable treatments are urgently needed. The causative agent of HAT is the protozoan Trypanosoma brucei ssp. Annotation of its genome confirms previous observations that T. brucei is a purine auxotroph. Incapable of de novo purine synthesis, these protozoan parasites rely on purine phosphoribosyltransferases to salvage purines from their hosts for the synthesis of purine monophosphates. Complete and accurate genome annotations in combination with the identification and characterization of the catalytic activity of purine salvage enzymes enables the development of target-specific therapies in addition to providing a deeper understanding of purine metabolism in T. brucei. In trypanosomes, purine phosphoribosyltransferases represent promising drug targets due to their essential and central role in purine salvage. Enzymes involved in adenine and adenosine salvage, such as adenine phosphoribosyltransferases (APRTs, EC 2.4.2.7), are of particular interest for their potential role in the activation of adenine and adenosine-based pro-drugs. Analysis of the T. brucei genome shows two putative aprt genes: APRT1 (Tb927.7.1780) and APRT2 (Tb927.7.1790). Here we report studies of the catalytic activity of each putative APRT, revealing that of the two T. brucei putative APRTs, only APRT1 is kinetically active, thereby signifying a genomic misannotation of Tb927.7.1790 (putative APRT2). Reliable genome annotation is necessary to establish potential drug targets and identify enzymes involved in adenine and adenosine-based pro-drug activation.
Collapse
Affiliation(s)
- Kayla Glockzin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Thomas D. Meek
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
- * E-mail: (TDM); (AK)
| | - Ardala Katzfuss
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
- * E-mail: (TDM); (AK)
| |
Collapse
|
13
|
Freitas-Mesquita AL, Meyer-Fernandes JR. Stage-Specific Class I Nucleases of Leishmania Play Important Roles in Parasite Infection and Survival. Front Cell Infect Microbiol 2021; 11:769933. [PMID: 34722348 PMCID: PMC8554303 DOI: 10.3389/fcimb.2021.769933] [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: 09/02/2021] [Accepted: 09/29/2021] [Indexed: 01/16/2023] Open
Abstract
Protozoans of the genus Leishmania are the causative agents of an important neglected tropical disease referred to as leishmaniasis. During their lifecycle, the parasites can colonize the alimentary tract of the sand fly vector and the parasitophorous vacuole of the mammalian host, differentiating into distinct stages. Motile promastigotes are found in the sand fly vector and are transmitted to the mammalian host during the insect blood meal. Once in the vertebrate host, the parasites differentiate into amastigotes and multiply inside macrophages. To successfully establish infection in mammalian hosts, Leishmania parasites exhibit various strategies to impair the microbicidal power of the host immune system. In this context, stage-specific class I nucleases play different and important roles related to parasite growth, survival and development. Promastigotes express 3’-nucleotidase/nuclease (3’-NT/NU), an ectoenzyme that can promote parasite escape from neutrophil extracellular traps (NET)-mediated death through extracellular DNA hydrolysis and increase Leishmania-macrophage interactions due to extracellular adenosine generation. Amastigotes express secreted nuclease activity during the course of human infection that may be involved in the purine salvage pathway and can mobilize extracellular nucleic acids available far from the parasite. Another nuclease expressed in amastigotes (P4/LmC1N) is located in the endoplasmic reticulum of the parasite and may be involved in mRNA stability and DNA repair. Homologs of this class I nuclease can induce protection against infection by eliciting a T helper 1-like immune response. These immunogenic properties render these nucleases good targets for the development of vaccines against leishmaniasis, mainly because amastigotes are the form responsible for the development and progression of the disease. The present review aims to present and discuss the roles played by different class I nucleases during the Leishmania lifecycle, especially regarding the establishment of mammalian host infection.
Collapse
Affiliation(s)
- Anita Leocadio Freitas-Mesquita
- Instituto de Bioquímica Médica Leopoldo De Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo De Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
| |
Collapse
|
14
|
Mwangi KW, Macharia RW, Bargul JL. Gene co-expression network analysis of Trypanosoma brucei in tsetse fly vector. Parasit Vectors 2021; 14:74. [PMID: 33482903 PMCID: PMC7821691 DOI: 10.1186/s13071-021-04597-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/13/2021] [Indexed: 01/14/2023] Open
Abstract
Background Trypanosoma brucei species are motile protozoan parasites that are cyclically transmitted by tsetse fly (genus Glossina) causing human sleeping sickness and nagana in livestock in sub-Saharan Africa. African trypanosomes display digenetic life cycle stages in the tsetse fly vector and in their mammalian host. Experimental work on insect-stage trypanosomes is challenging because of the difficulty in setting up successful in vitro cultures. Therefore, there is limited knowledge on the trypanosome biology during its development in the tsetse fly. Consequently, this limits the development of new strategies for blocking parasite transmission in the tsetse fly. Methods In this study, RNA-Seq data of insect-stage trypanosomes were used to construct a T. brucei gene co-expression network using the weighted gene co-expression analysis (WGCNA) method. The study identified significant enriched modules for genes that play key roles during the parasite’s development in tsetse fly. Furthermore, potential 3′ untranslated region (UTR) regulatory elements for genes that clustered in the same module were identified using the Finding Informative Regulatory Elements (FIRE) tool. Results A fraction of gene modules (12 out of 27 modules) in the constructed network were found to be enriched in functional roles associated with the cell division, protein biosynthesis, mitochondrion, and cell surface. Additionally, 12 hub genes encoding proteins such as RNA-binding protein 6 (RBP6), arginine kinase 1 (AK1), brucei alanine-rich protein (BARP), among others, were identified for the 12 significantly enriched gene modules. In addition, the potential regulatory elements located in the 3′ untranslated regions of genes within the same module were predicted. Conclusions The constructed gene co-expression network provides a useful resource for network-based data mining to identify candidate genes for functional studies. This will enhance understanding of the molecular mechanisms that underlie important biological processes during parasite’s development in tsetse fly. Ultimately, these findings will be key in the identification of potential molecular targets for disease control.![]()
Collapse
Affiliation(s)
- Kennedy W Mwangi
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya. .,Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000-00200, Nairobi, Kenya.
| | | | - Joel L Bargul
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.,Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000-00200, Nairobi, Kenya
| |
Collapse
|
15
|
Synthesis and evaluation of a collection of purine-like C-nucleosides as antikinetoplastid agents. Eur J Med Chem 2020; 212:113101. [PMID: 33385837 DOI: 10.1016/j.ejmech.2020.113101] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 12/17/2022]
Abstract
The kinetoplastid parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. are the causative agents of neglected tropical diseases with a serious burden in several parts of the world. These parasites are incapable of synthesizing purines de novo, and therefore rely on ingenious purine salvage pathways to acquire and process purines from their host. Purine nucleoside analogs that may interfere with these pathways therefore constitute a privileged source of new antikinetoplastid agents. In this study, we synthetized a collection of C-nucleosides employing five different heterocyclic nucleobase surrogates. C-nucleosides are chemically and enzymatically stable and allow for extensive structural modification. Inspired by earlier 7-deazaadenosine nucleosides and known antileishmanial C-nucleosides, we introduced different modifications tailored towards antikinetoplastid activity. Both adenosine and inosine analogs were synthesized with the aim of discovering new antikinetoplastid hits and expanding knowledge of structure-activity relationships. Several promising hits with potent activity against Trypanosoma brucei, Trypanosoma cruzi and Leishmania infantum were discovered, and the nature of the nucleobase surrogate was found to have a profound influence on the selectivity profile of the compounds.
Collapse
|
16
|
Production of a polyclonal antibody against inosine-uridine preferring nucleoside hydrolase of Acanthamoeba castellanii and its access to diagnosis of Acanthamoeba keratitis. PLoS One 2020; 15:e0239867. [PMID: 32997695 PMCID: PMC7526901 DOI: 10.1371/journal.pone.0239867] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/14/2020] [Indexed: 11/21/2022] Open
Abstract
Acanthamoeba keratitis (AK) is a rare disease but its prevalence throughout the globe continues to grow, primarily due to increased contact lens usage. Since early-stage symptoms associated with AK closely resemble those from other corneal infections, accurate diagnosis is difficult and this often results in delayed treatment and exacerbation of the disease, which can lead to permanent visual impairment. Accordingly, developing a rapid Acanthamoeba–specific diagnostic method is highly desired. In the present study, a rapid and differential method for AK diagnosis was developed using the secretory proteins derived from the pathogenic Acanthamoeba. Among the vast quantities of proteins secreted by the pathogenic Acanthamoeba, an open reading frame of the inosine-uridine preferring nucleoside hydrolase (IPNH) gene was obtained. After expressing and purifying the IPNH protein using the pGEX 4T-3 vector system, mice were immunized with the purified proteins for polyclonal antibody generation. Western blot was performed using protein lysates of the human corneal cell, non-pathogenic amoeba, pathogenic amoeba, and clinical amoeba isolate along with lysates from other causes of keratitis such as Staphylococcus aureus, Pseudomonas aeruginosa, and Fusarium solani to confirm Acanthamoeba-specificity. Western blot using the polyclonal IPNH antibody revealed that IPNH was Acanthamoeba-specific since these proteins were only observed in lysates of Acanthamoeba origin or its culture media. Our findings indicate that the IPNH antibody of Acanthamoeba may serve as a potential agent for rapid and differential AK diagnosis.
Collapse
|
17
|
Allosteric regulation accompanied by oligomeric state changes of Trypanosoma brucei GMP reductase through cystathionine-β-synthase domain. Nat Commun 2020; 11:1837. [PMID: 32296055 PMCID: PMC7160140 DOI: 10.1038/s41467-020-15611-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 03/19/2020] [Indexed: 11/09/2022] Open
Abstract
Guanosine 5'-monophosphate reductase (GMPR) is involved in the purine salvage pathway and is conserved throughout evolution. Nonetheless, the GMPR of Trypanosoma brucei (TbGMPR) includes a unique structure known as the cystathionine-β-synthase (CBS) domain, though the role of this domain is not fully understood. Here, we show that guanine and adenine nucleotides exert positive and negative effects, respectively, on TbGMPR activity by binding allosterically to the CBS domain. The present structural analyses revealed that TbGMPR forms an octamer that shows a transition between relaxed and twisted conformations in the absence and presence of guanine nucleotides, respectively, whereas the TbGMPR octamer dissociates into two tetramers when ATP is available instead of guanine nucleotides. These findings demonstrate that the CBS domain plays a key role in the allosteric regulation of TbGMPR by facilitating the transition of its oligomeric state depending on ligand nucleotide availability.
Collapse
|
18
|
Acyclic nucleoside phosphonates as possible chemotherapeutics against Trypanosoma brucei. Drug Discov Today 2020; 25:1043-1053. [PMID: 32135205 DOI: 10.1016/j.drudis.2020.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/24/2020] [Accepted: 02/20/2020] [Indexed: 11/20/2022]
Abstract
Human African trypanosomiasis is a life-threatening illness caused by Trypanosoma brucei. Owing to the toxic side effects of the available therapeutics, new medications for this disease are needed. One potential drug target is the 6-oxopurine phosphoribosyltransferases (PRTs), the activity of which is crucial to produce purine nucleotide monophosphates required for DNA and RNA synthesis. Inhibitors of the 6-oxopurine PRTs that show promising results as drug leads are the acyclic nucleoside phosphonates (ANPs). ANPs are very flexible in their structure, enabling important conformational changes to facilitate the binding of this class of compounds in the active site of the 6-oxopurine PRTs.
Collapse
|
19
|
Valente M, Vidal AE, González-Pacanowska D. Targeting Kinetoplastid and Apicomplexan Thymidylate Biosynthesis as an Antiprotozoal Strategy. Curr Med Chem 2019; 26:4262-4279. [PMID: 30259810 DOI: 10.2174/0929867325666180926154329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 03/23/2018] [Accepted: 09/14/2018] [Indexed: 02/04/2023]
Abstract
Kinetoplastid and apicomplexan parasites comprise a group of protozoans responsible for human diseases, with a serious impact on human health and the socioeconomic growth of developing countries. Chemotherapy is the main option to control these pathogenic organisms and nucleotide metabolism is considered a promising area for the provision of antimicrobial therapeutic targets. Impairment of thymidylate (dTMP) biosynthesis severely diminishes the viability of parasitic protozoa and the absence of enzymatic activities specifically involved in the formation of dTMP (e.g. dUTPase, thymidylate synthase, dihydrofolate reductase or thymidine kinase) results in decreased deoxythymidine triphosphate (dTTP) levels and the so-called thymineless death. In this process, the ratio of deoxyuridine triphosphate (dUTP) versus dTTP in the cellular nucleotide pool has a crucial role. A high dUTP/dTTP ratio leads to uracil misincorporation into DNA, the activation of DNA repair pathways, DNA fragmentation and eventually cell death. The essential character of dTMP synthesis has stimulated interest in the identification and development of drugs that specifically block the biochemical steps involved in thymine nucleotide formation. Here, we review the available literature in relation to drug discovery studies targeting thymidylate biosynthesis in kinetoplastid (genera Trypanosoma and Leishmania) and apicomplexan (Plasmodium spp and Toxoplasma gondii) protozoans. The most relevant findings concerning novel inhibitory molecules with antiparasitic activity against these human pathogens are presented herein.
Collapse
Affiliation(s)
- María Valente
- Instituto de Parasitologia y Biomedicina "Lopez-Neyra", Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Antonio E Vidal
- Instituto de Parasitologia y Biomedicina "Lopez-Neyra", Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitologia y Biomedicina "Lopez-Neyra", Consejo Superior de Investigaciones Científicas, Granada, Spain
| |
Collapse
|
20
|
Auletta S, Caravan W, Persaud JK, Thuilot SF, Brown DG, Parkin DW, Stockman BJ. Discovery of Ligand-Efficient Scaffolds for the Design of Novel Trichomonas vaginalis Uridine Nucleoside Ribohydrolase Inhibitors Using Fragment Screening. ACS OMEGA 2019; 4:16226-16232. [PMID: 31592163 PMCID: PMC6777076 DOI: 10.1021/acsomega.9b02472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
Trichomoniasis is caused by the parasitic protozoan Trichomonas vaginalis. The increasing prevalence of strains resistant to the current 5-nitroimidazole treatments creates the need for novel therapies. T. vaginalis cannot synthesize purine and pyrimidine rings and requires salvage pathway enzymes to obtain them from host nucleosides. The uridine nucleoside ribohydrolase was screened using an 19F NMR-based activity assay against a 2000-compound fragment diversity library. Several series of inhibitors were identified including scaffolds based on acetamides, cyclic ureas or ureas, pyridines, and pyrrolidines. A number of potent singleton compounds were identified, as well. Eighteen compounds with IC50 values of 20 μM or lower were identified, including some with ligand efficiency values of 0.5 or greater. Detergent and jump-dilution counter screens validated all scaffold classes as target-specific, reversible inhibitors. Identified scaffolds differ substantially from 5-nitroimidazoles. Medicinal chemistry using the structure-activity relationship emerging from the fragment hits is being pursued to discover nanomolar inhibitors.
Collapse
Affiliation(s)
- Shannon Auletta
- Department
of Chemistry, Adelphi University, 1 South Avenue, Garden City, New York 11530, Unites States
| | - Wagma Caravan
- Department
of Chemistry, Adelphi University, 1 South Avenue, Garden City, New York 11530, Unites States
| | - Julia K. Persaud
- Department
of Chemistry, Adelphi University, 1 South Avenue, Garden City, New York 11530, Unites States
| | - Samantha F. Thuilot
- Department
of Chemistry, Adelphi University, 1 South Avenue, Garden City, New York 11530, Unites States
| | - Dean G. Brown
- Hit
Discovery, Discovery Sciences, IMED Biotech
Unit, AstraZeneca, 35
Gatehouse Drive, Waltham, Massachusetts 02451, United States
| | - David W. Parkin
- Department
of Chemistry, Adelphi University, 1 South Avenue, Garden City, New York 11530, Unites States
| | - Brian J. Stockman
- Department
of Chemistry, Adelphi University, 1 South Avenue, Garden City, New York 11530, Unites States
| |
Collapse
|
21
|
Wang W, Cui J, Zhao Y, Ye C, Zhou S, Guo X, Zhang C, Li J, Wu D. A label-free approach to detect cell viability/cytotoxicity based on intracellular xanthine/guanine by electrochemical method. J Pharmacol Toxicol Methods 2019; 100:106625. [PMID: 31445082 DOI: 10.1016/j.vascn.2019.106625] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/04/2019] [Accepted: 08/14/2019] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Cell viability and cytotoxicity is one of the most important toxicology indicators. In this study, an electrochemical method for detecting cell viability and cytotoxicity was discussed with the intracellular small molecule metabolite purines as indexes. METHODS The electrochemical behaviors of Balb/c 3T3, CHO, PC-12 and V79 cell suspensions were studies by cyclic voltammetry, and cell viability and cytotoxicity of four cell lines were compared by electrochemical, cell counting, 3-(4,5-dimethyl-2-Thiazyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) and trypan blue exclusion methods. RESULTS Four cell lines all showed an oxidation peak derived from mixture of xanthine and guanine at about 0.7 V. Using intracellular xanthine and guanine as index, the electrochemical method could not only describe the cell growth curves of four cell lines, but also reflect the changes of cell viability at various phases of the cell growth prior to the counting method. Compared with MTT, cell counting and trypan blue staining methods, the electrochemical method could detect the cytotoxicity of carcinogen earlier and more sensitively. DISCUSSION The electrochemical method could track the change of intracellular xanthine and guanine contents, and used it as index to detect cell viability and cytotoxicity at the molecular level without markers, showing greater advantages over the method with apparent cell proliferation as the endpoint.
Collapse
Affiliation(s)
- Wenqiang Wang
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China
| | - Jiwen Cui
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China
| | - Yanli Zhao
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China
| | - Cai Ye
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China
| | - Shi Zhou
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China
| | - Xiaoling Guo
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China
| | - Chunbin Zhang
- Department of Biology, The Basic Medical College, Jiamusi University, Heilongjiang 154007, China.
| | - Jinlian Li
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China.
| | - Dongmei Wu
- College of Pharmacy, Jiamusi University, Heilongjiang 154007, China.
| |
Collapse
|
22
|
Murphy SC, Duke ER, Shipman KJ, Jensen RL, Fong Y, Ferguson S, Janes HE, Gillespie K, Seilie AM, Hanron AE, Rinn L, Fishbaugher M, VonGoedert T, Fritzen E, Kappe SH, Chang M, Sousa JC, Marcsisin SR, Chalon S, Duparc S, Kerr N, Möhrle JJ, Andenmatten N, Rueckle T, Kublin JG. A Randomized Trial Evaluating the Prophylactic Activity of DSM265 Against Preerythrocytic Plasmodium falciparum Infection During Controlled Human Malarial Infection by Mosquito Bites and Direct Venous Inoculation. J Infect Dis 2019; 217:693-702. [PMID: 29216395 DOI: 10.1093/infdis/jix613] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/29/2017] [Indexed: 11/13/2022] Open
Abstract
Background DSM265 is a selective inhibitor of Plasmodium dihydroorotate dehydrogenase that fully protected against controlled human malarial infection (CHMI) by direct venous inoculation of Plasmodium falciparum sporozoites when administered 1 day before challenge and provided partial protection when administered 7 days before challenge. Methods A double-blinded, randomized, placebo-controlled trial was performed to assess safety, tolerability, pharmacokinetics, and efficacy of 1 oral dose of 400 mg of DSM265 before CHMI. Three cohorts were studied, with DSM265 administered 3 or 7 days before direct venous inoculation of sporozoites or 7 days before 5 bites from infected mosquitoes. Results DSM265-related adverse events consisted of mild-to-moderate headache and gastrointestinal symptoms. DSM265 concentrations were consistent with pharmacokinetic models (mean area under the curve extrapolated to infinity, 1707 µg*h/mL). Placebo-treated participants became positive by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and were treated 7-10 days after CHMI. Among DSM265-treated subjects, 2 of 6 in each cohort were sterilely protected. DSM265-treated recipients had longer times to development of parasitemia than placebo-treated participants (P < .004). Conclusions This was the first CHMI study of a novel antimalarial compound to compare direct venous inoculation of sporozoites and mosquito bites. Times to qRT-PCR positivity and treatment were comparable for both routes. DSM265 given 3 or 7 days before CHMI was safe and well tolerated but sterilely protected only one third of participants.
Collapse
Affiliation(s)
- Sean C Murphy
- Department of Laboratory Medicine, University of Washington, Seattle, Washington.,Department of Microbiology, University of Washington, Seattle, Washington.,Center for Emerging and Re-emerging Infectious Diseases, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Elizabeth R Duke
- Department of Medicine, University of Washington, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Kelly J Shipman
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Ryan L Jensen
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Youyi Fong
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Sue Ferguson
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Holly E Janes
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Kevin Gillespie
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Annette M Seilie
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Amelia E Hanron
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Laurie Rinn
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Matthew Fishbaugher
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Tracie VonGoedert
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Emma Fritzen
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Stefan H Kappe
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Ming Chang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Jason C Sousa
- Walter Reed Army Institute of Research, Silver Spring, Maryland
| | | | | | | | - Nicola Kerr
- Medicines for Malaria Venture, Geneva, Switzerland
| | | | | | | | - James G Kublin
- Department of Global Health, University of Washington, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| |
Collapse
|
23
|
Freitas-Mesquita AL, Dick CF, Dos-Santos ALA, Nascimento MTC, Rochael NC, Saraiva EM, Meyer-Fernandes JR. Cloning, expression and purification of 3'-nucleotidase/nuclease, an enzyme responsible for the Leishmania escape from neutrophil extracellular traps. Mol Biochem Parasitol 2019; 229:6-14. [PMID: 30772424 DOI: 10.1016/j.molbiopara.2019.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 02/05/2019] [Accepted: 02/11/2019] [Indexed: 01/04/2023]
Abstract
Leishmaniasis is one of the most significant of the neglected tropical diseases, with 350 million people in 98 countries worldwide living at risk of developing one of the many forms of the disease. During the transmission of the parasite from its vector to the vertebrate host, neutrophils are rapidly recruited to the site of the sandfly bite. Using different strategies, neutrophils can often kill a large number of parasites. However, some parasites can resist neutrophil-killing mechanisms and survive until macrophage arrival at the infection site. One of the strategies for neutrophil-mediated killing is the production of neutrophil extracellular traps (NETs). Because of its ecto-localized nuclease activity, the enzyme 3'-nucleotidase/nuclease (3'NT/NU), present in different Leishmania species, was recently identified as part of a possible parasite escape mechanism from NET-mediated death. Previous studies showed that 3'NT/NU also plays an important role in the establishment of Leishmania infection by generating extracellular adenosine that favors the parasite and macrophage interaction. This study aims to deepen the knowledge about 3'NT/NU, mainly with respect to its nuclease activity that is little studied in the current literature. For this, we cloned, expressed and purified the recombinant La3'NT/NU and have confirmed its contribution to the parasite escape from NET-mediated killing.
Collapse
Affiliation(s)
- Anita Leocadio Freitas-Mesquita
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Claudia F Dick
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - André L A Dos-Santos
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Michelle T C Nascimento
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Natalia C Rochael
- Instituto de Microbiologia Prof. Paulo de Góes (IMPPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Elvira M Saraiva
- Instituto de Microbiologia Prof. Paulo de Góes (IMPPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil.
| |
Collapse
|
24
|
Campagnaro GD, de Freitas Nascimento J, Girard RB, Silber AM, de Koning HP. Cloning and characterisation of the Equilibrative Nucleoside Transporter family of Trypanosoma cruzi: ultra-high affinity and selectivity to survive in the intracellular niche. Biochim Biophys Acta Gen Subj 2018; 1862:2750-2763. [DOI: 10.1016/j.bbagen.2018.08.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/22/2018] [Accepted: 08/23/2018] [Indexed: 12/27/2022]
|
25
|
Lenz SAP, Wetmore SD. Structural explanation for the tunable substrate specificity of an E. coli nucleoside hydrolase: insights from molecular dynamics simulations. J Comput Aided Mol Des 2018; 32:1375-1388. [PMID: 30478756 DOI: 10.1007/s10822-018-0178-y] [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: 07/20/2018] [Accepted: 11/21/2018] [Indexed: 11/25/2022]
Abstract
Parasitic protozoa rely on nucleoside hydrolases that play key roles in the purine salvage pathway by catalyzing the hydrolytic cleavage of the N-glycosidic bond that connects nucleobases to ribose sugars. Cytidine-uridine nucleoside hydrolase (CU-NH) is generally specific toward pyrimidine nucleosides; however, previous work has shown that replacing two active site residues with Tyr, specifically the Thr223Tyr and Gln227Tyr mutations, allows CU-NH to process inosine. The current study uses molecular dynamics (MD) simulations to gain atomic-level insight into the activity of wild-type and mutant E. coli CU-NH toward inosine. By examining systems that differ in the identity and protonation states of active site catalytic residues, key enzyme-substrate interactions that dictate the substrate specificity of CU-NH are identified. Regardless of the wild-type or mutant CU-NH considered, our calculations suggest that inosine binding is facilitated by interactions of the ribose moiety with active site residues and Ca2+, and π-interactions between two His residues (His82 and His239) and the nucleobase. However, the lack of observed activity toward inosine for wild-type CU-NH is explained by no residue being correctly aligned to stabilize the departing nucleobase. In contrast, a hydrogen-bonding network between hypoxanthine and a newly identified general acid (Asp15) is present when the two Tyr mutations are engineered into the active site. Investigation of the single CU-NH mutants reveals that this hydrogen-bonding network is only maintained when both Tyr mutations are present due to a π-interaction between the residues. These results rationalize previous experiments that show the single Tyr mutants are unable to efficiently hydrolyze inosine and explain how the Tyr residues work synergistically in the double mutant to stabilize the nucleobase leaving group during hydrolysis. Overall, our simulations provide a structural explanation for the substrate specificity of nucleoside hydrolases, which may be used to rationally develop new treatments for kinetoplastid diseases.
Collapse
Affiliation(s)
- Stefan A P Lenz
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, AB, T1K 3M4, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, AB, T1K 3M4, Canada.
| |
Collapse
|
26
|
Patel B, Patel D, Parmar K, Chauhan R, Singh DD, Pappachan A. L . donovani XPRT: Molecular characterization and evaluation of inhibitors. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:426-441. [DOI: 10.1016/j.bbapap.2017.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 11/30/2017] [Accepted: 12/08/2017] [Indexed: 10/18/2022]
|
27
|
Doleželová E, Terán D, Gahura O, Kotrbová Z, Procházková M, Keough D, Špaček P, Hocková D, Guddat L, Zíková A. Evaluation of the Trypanosoma brucei 6-oxopurine salvage pathway as a potential target for drug discovery. PLoS Negl Trop Dis 2018; 12:e0006301. [PMID: 29481567 PMCID: PMC5843355 DOI: 10.1371/journal.pntd.0006301] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 03/08/2018] [Accepted: 02/05/2018] [Indexed: 01/19/2023] Open
Abstract
Due to toxicity and compliance issues and the emergence of resistance to current medications new drugs for the treatment of Human African Trypanosomiasis are needed. A potential approach to developing novel anti-trypanosomal drugs is by inhibition of the 6-oxopurine salvage pathways which synthesise the nucleoside monophosphates required for DNA/RNA production. This is in view of the fact that trypanosomes lack the machinery for de novo synthesis of the purine ring. To provide validation for this approach as a drug target, we have RNAi silenced the three 6-oxopurine phosphoribosyltransferase (PRTase) isoforms in the infectious stage of Trypanosoma brucei demonstrating that the combined activity of these enzymes is critical for the parasites’ viability. Furthermore, we have determined crystal structures of two of these isoforms in complex with several acyclic nucleoside phosphonates (ANPs), a class of compound previously shown to inhibit 6-oxopurine PRTases from several species including Plasmodium falciparum. The most potent of these compounds have Ki values as low as 60 nM, and IC50 values in cell based assays as low as 4 μM. This data provides a solid platform for further investigations into the use of this pathway as a target for anti-trypanosomal drug discovery. Human African Trypanosomiasis (HAT) is a life-threatening infectious disease caused by the protozoan parasite, Trypanosoma brucei. Current treatments suffer from low efficacy, toxicity issues and complex medication regimens. Moreover, an alarming number of these parasites are demonstrating resistance to current drugs. For these reasons, there is a renewed effort to develop new classes of modern therapeutics based upon the unique T. brucei cellular processes. One potential new drug target is 6-oxopurine phosphoribosyltransferase (PRTase), an enzyme central to the purine salvage pathway and whose activity is critical for the production of the nucleotides (GMP and IMP) required for DNA/RNA synthesis within this protozoan parasite. We demonstrated that T. brucei encodes two isoforms of hypoxanthine-guanine PRTases (HGPRT) and one hypoxanthine-guanine-xanthine PRTase (HGXPRT). The concurrent activity of these enzymes is required for the normal cell growth in vitro. Moreover, acyclic nucleoside phosphonates represent a promising class of potent and selective compounds as they inhibit the enzymes with Ki values in nanomolar range and exert cytotoxic effects on T. brucei cells grown in vitro with EC50 values in the single digit micromolar range. Our results provide a new foundation for further investigations of these compounds in vivo and suggest that 6-oxopurine salvage pathway represents a possible target for future drug discovery efforts directed at eliminating HAT.
Collapse
Affiliation(s)
- Eva Doleželová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská, České Budějovice, Czech Republic
| | - David Terán
- The School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská, České Budějovice, Czech Republic
| | - Zuzana Kotrbová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Michaela Procházková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Dianne Keough
- The School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Petr Špaček
- The Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. Prague, Czech Republic
| | - Dana Hocková
- The Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. Prague, Czech Republic
| | - Luke Guddat
- The School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- * E-mail: (AZ); (LWG)
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
- * E-mail: (AZ); (LWG)
| |
Collapse
|
28
|
Wielgus-Kutrowska B, Grycuk T, Bzowska A. Part-of-the-sites binding and reactivity in the homooligomeric enzymes - facts and artifacts. Arch Biochem Biophys 2018; 642:31-45. [PMID: 29408402 DOI: 10.1016/j.abb.2018.01.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 01/13/2018] [Accepted: 01/17/2018] [Indexed: 01/18/2023]
Abstract
For a number of enzymes composed of several subunits with the same amino acid sequence, it was documented, or suggested, that binding of a ligand, or catalysis, is carried out by a single subunit. This phenomenon may be the result of a pre-existent asymmetry of subunits or a limiting case of the negative cooperativity, and is sometimes called "half-of-the-sites binding (or reactivity)" for dimers and could be called "part-of-the-sites binding (or reactivity)" for higher oligomers. In this article, we discuss molecular mechanisms that may result in "part-of-the-sites binding (and reactivity)", offer possible explanations why it may have a beneficial role in enzyme function, and point to experimental problems in documenting this behaviour. We describe some cases, for which such a mechanism was first reported and later disproved. We also give several examples of enzymes, for which this mechanism seems to be well documented, and profitable. A majority of enzymes identified in this study as half-of-the-sites binding (or reactive) use it in the flip-flop version, in which "half-of-the-sites" refers to a particular moment in time. In general, the various variants of the mechanism seems to be employed often by oligomeric enzymes for allosteric regulation to enhance the efficiency of enzymatic reactions in many key metabolic pathways.
Collapse
Affiliation(s)
- Beata Wielgus-Kutrowska
- Division of Biophysics, Institute of Experimental Physics, Department of Physics, University of Warsaw, Pasteura 5, Warsaw, 02-093, Poland.
| | - Tomasz Grycuk
- Division of Biophysics, Institute of Experimental Physics, Department of Physics, University of Warsaw, Pasteura 5, Warsaw, 02-093, Poland
| | - Agnieszka Bzowska
- Division of Biophysics, Institute of Experimental Physics, Department of Physics, University of Warsaw, Pasteura 5, Warsaw, 02-093, Poland.
| |
Collapse
|
29
|
Pourshab M, Asghari S, Mohseni M. Synthesis and Antibacterial Evaluation of Novel Spiro[indole-pyrimidine]ones. J Heterocycl Chem 2017. [DOI: 10.1002/jhet.3021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Maryam Pourshab
- Department of Organic Chemistry, Faculty of Chemistry; University of Mazandaran; Babolsar 47416-95447 Iran
| | - Sakineh Asghari
- Department of Organic Chemistry, Faculty of Chemistry; University of Mazandaran; Babolsar 47416-95447 Iran
- Nano and Biotechnology Research Group; University of Mazandaran; Babolsar 47416-95447 Iran
| | - Mojtaba Mohseni
- Nano and Biotechnology Research Group; University of Mazandaran; Babolsar 47416-95447 Iran
- Department of Microbiology, Faculty of Science; University of Mazandaran; Babolsar 47416-95447 Iran
| |
Collapse
|
30
|
El Kouni MH. Pyrimidine metabolism in schistosomes: A comparison with other parasites and the search for potential chemotherapeutic targets. Comp Biochem Physiol B Biochem Mol Biol 2017; 213:55-80. [PMID: 28735972 PMCID: PMC5593796 DOI: 10.1016/j.cbpb.2017.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/29/2017] [Accepted: 07/03/2017] [Indexed: 12/18/2022]
Abstract
Schistosomes are responsible for the parasitic disease schistosomiasis, an acute and chronic parasitic ailment that affects >240 million people in 70 countries worldwide. It is the second most devastating parasitic disease after malaria. At least 200,000 deaths per year are associated with the disease. In the absence of the availability of vaccines, chemotherapy is the main stay for combating schistosomiasis. The antischistosomal arsenal is currently limited to a single drug, Praziquantel, which is quite effective with a single-day treatment and virtually no host-toxicity. Recently, however, the question of reduced activity of Praziquantel has been raised. Therefore, the search for alternative antischistosomal drugs merits the study of new approaches of chemotherapy. The rational design of a drug is usually based on biochemical and physiological differences between pathogens and host. Pyrimidine metabolism is an excellent target for such studies. Schistosomes, unlike most of the host tissues, require a very active pyrimidine metabolism for the synthesis of DNA and RNA. This is essential for the production of the enormous numbers of eggs deposited daily by the parasite to which the granulomas response precipitates the pathogenesis of schistosomiasis. Furthermore, there are sufficient differences between corresponding enzymes of pyrimidine metabolism from the host and the parasite that can be exploited to design specific inhibitors or "subversive substrates" for the parasitic enzymes. Specificities of pyrimidine transport also diverge significantly between parasites and their mammalian host. This review deals with studies on pyrimidine metabolism in schistosomes and highlights the unique characteristic of this metabolism that could constitute excellent potential targets for the design of safe and effective antischistosomal drugs. In addition, pyrimidine metabolism in schistosomes is compared with that in other parasites where studies on pyrimidine metabolism have been more elaborate, in the hope of providing leads on how to identify likely chemotherapeutic targets which have not been looked at in schistosomes.
Collapse
Affiliation(s)
- Mahmoud H El Kouni
- Department of Pharmacology and Toxicology, Center for AIDS Research, Comprehensive Cancer Center, General Clinical Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| |
Collapse
|
31
|
Wangsanut T, Ghosh AK, Metzger PG, Fonzi WA, Rolfes RJ. Grf10 and Bas1 Regulate Transcription of Adenylate and One-Carbon Biosynthesis Genes and Affect Virulence in the Human Fungal Pathogen Candida albicans. mSphere 2017; 2:e00161-17. [PMID: 28776040 PMCID: PMC5541157 DOI: 10.1128/msphere.00161-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/11/2017] [Indexed: 11/21/2022] Open
Abstract
Candida albicans is an opportunistic human fungal pathogen that causes superficial fungal infections and lethal systemic infections. To colonize and establish infections, C. albicans coordinates the expression of virulence and metabolic genes. Previous work showed that the homeodomain transcription factor Grf10 is required for formation of hyphae, a virulence factor. Here we report global gene expression analysis of a grf10Δ strain using a DNA microarray and identify genes for de novo adenylate biosynthesis (ADE genes), one-carbon metabolism, and a nucleoside permease (NUP). Upregulation of these genes in response to adenine limitation required both Grf10 and the myb protein Bas1, as shown by quantitative real-time PCR (qRT-PCR). Phenotypic analysis showed that both mutants exhibited growth defects when grown in the absence of adenine, and the doubling time was slower for the bas1Δ mutant. Bas1 is required for basal expression of these genes, whereas NUP expression is more dependent upon Grf10. Disruption of BAS1 led to only modest defects in hypha formation and weak attenuation of virulence in a systemic mouse model of infection, as opposed to the previously reported strong effects found in the grf10Δ mutant. Our data are consistent with a model in which Grf10 coordinates metabolic effects on nucleotide metabolism by interaction with Bas1 and indicate that AMP biosynthesis and its regulation are important for C. albicans growth and virulence. IMPORTANCECandida albicans is a commensal and a common constituent of the human microbiota; however, it can become pathogenic and cause infections in both immunocompetent and immunocompromised people. C. albicans exhibits remarkable metabolic versatility as it can colonize multiple body sites as a commensal or pathogen. Understanding how C. albicans adapts metabolically to each ecological niche is essential for developing novel therapeutic approaches. Purine metabolism has been targeted pharmaceutically in several diseases; however, the regulation of this pathway has not been fully elucidated in C. albicans. Here, we report how C. albicans controls the AMP de novo biosynthesis pathway in response to purine availability. We show that the lack of the transcription factors Grf10 and Bas1 leads to purine metabolic dysfunction, and this dysfunction affects the ability of C. albicans to establish infections.
Collapse
Affiliation(s)
| | - Anup K. Ghosh
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Peter G. Metzger
- Department of Biology, Georgetown University, Washington, DC, USA
| | - William A. Fonzi
- Department of Microbiology and Immunology, Georgetown University, Washington, DC, USA
| | - Ronda J. Rolfes
- Department of Biology, Georgetown University, Washington, DC, USA
| |
Collapse
|
32
|
Freitas-Mesquita AL, Meyer-Fernandes JR. 3'nucleotidase/nuclease in protozoan parasites: Molecular and biochemical properties and physiological roles. Exp Parasitol 2017; 179:1-6. [PMID: 28587841 DOI: 10.1016/j.exppara.2017.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/16/2017] [Accepted: 06/02/2017] [Indexed: 12/28/2022]
Abstract
3'-nucleotidase/nuclease (3'NT/NU) is a bi-functional enzyme that is able to hydrolyze 3'-monophosphorylated nucleotides and nucleic acids. This review summarizes the major molecular and biochemical properties of this enzyme in different trypanosomatid species. Sequence analysis of the gene encoding 3'NT/NU in Leishmania and Crithidia species showed that the protein possesses five highly conserved regions that are characteristic of members of the class I nuclease family. 3'NT/NU presents a molecular weight of approximately 40 kDa, which is conserved among the studied species. Throughout the review, we discuss inhibitors and substrate specificity, relating them to the putative structure of the enzyme. Finally, we present the major biological roles performed by 3'NT/NU. The involvement of 3'NT/NU in the purine salvage pathway was confirmed by the increase of activity and expression of the enzyme when the parasites were submitted to purine starvation. The generation of extracellular adenosine is also important to the modulation of the host immune response. Interaction assays involving Leishmania parasites and macrophages indicated that 3'-nucleotidase activity increases the association index between them. Recently, it was shown that 3'NT/NU plays a role in parasite escape from neutrophil extracellular traps, one of the first mechanisms of the host immune system for preventing infection.
Collapse
Affiliation(s)
- Anita Leocadio Freitas-Mesquita
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-590, Brazil.
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-590, Brazil.
| |
Collapse
|
33
|
Karami M, Jalali C, Mirzaie S. Combined virtual screening, MMPBSA, molecular docking and dynamics studies against deadly anthrax: An in silico effort to inhibit Bacillus anthracis nucleoside hydrolase. J Theor Biol 2017; 420:180-189. [DOI: 10.1016/j.jtbi.2017.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 03/03/2017] [Accepted: 03/10/2017] [Indexed: 10/20/2022]
|
34
|
Sarwono AEY, Suganuma K, Mitsuhashi S, Okada T, Musinguzi SP, Shigetomi K, Inoue N, Ubukata M. Identification and characterization of guanosine 5'-monophosphate reductase of Trypanosoma congolense as a drug target. Parasitol Int 2017; 66:537-544. [PMID: 28366788 DOI: 10.1016/j.parint.2017.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/17/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Abstract
Trypanosoma congolense is one of the most prevalent pathogens which causes trypanosomosis in African animals, resulting in a significant economic loss. In its life cycle, T. congolense is incapable of synthesizing purine nucleotides via a de novo pathway, and thus relies on a salvage pathway to survive. In this study, we identified a gene from T. congolense, TcIL3000_5_1940, as a guanosine 5'-monophosphate reductase (GMPR), an enzyme that modulates the concentration of intracellular guanosine in the pathogen. The recombinant protein was expressed in Escherichia coli, and the gene product was enzymatically confirmed as a unique GMPR, designated as rTcGMPR. This enzyme was constitutively expressed in glycosomes at all of the parasite's developmental stages similar to other purine nucleotide metabolic enzymes. Mycophenolic acid (MPA) was found to inhibit rTcGMPR activity. Hence, it is a potential lead compound for the design of trypanocidal agents, specifically GMPR inhibitor.
Collapse
Affiliation(s)
- Albertus Eka Yudistira Sarwono
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| | - Keisuke Suganuma
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan; Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Shinya Mitsuhashi
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| | - Tadashi Okada
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan; Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Simon Peter Musinguzi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Kengo Shigetomi
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| | - Noboru Inoue
- Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Makoto Ubukata
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
| |
Collapse
|
35
|
Singh RK, Steyaert J, Versées W. Structural and biochemical characterization of the nucleoside hydrolase from C. elegans reveals the role of two active site cysteine residues in catalysis. Protein Sci 2017; 26:985-996. [PMID: 28218438 DOI: 10.1002/pro.3141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/10/2017] [Accepted: 02/10/2017] [Indexed: 12/28/2022]
Abstract
Nucleoside hydrolases (NHs) catalyze the hydrolysis of the N-glycoside bond in ribonucleosides and are found in all three domains of life. Although in parasitic protozoa a role in purine salvage has been well established, their precise function in bacteria and higher eukaryotes is still largely unknown. NHs have been classified into three homology groups based on the conservation of active site residues. While many structures are available of representatives of group I and II, structural information for group III NHs is lacking. Here, we report the first crystal structure of a purine-specific nucleoside hydrolase belonging to homology group III from the nematode Caenorhabditis elegans (CeNH) to 1.65Å resolution. In contrast to dimeric purine-specific NHs from group II, CeNH is a homotetramer. A cysteine residue that characterizes group III NHs (Cys253) structurally aligns with the catalytic histidine and tryptophan residues of group I and group II enzymes, respectively. Moreover, a second cysteine (Cys42) points into the active site of CeNH. Substrate docking shows that both cysteine residues are appropriately positioned to interact with the purine ring. Site-directed mutagenesis and kinetic analysis proposes a catalytic role for both cysteines residues, with Cys253 playing the most prominent role in leaving group activation.
Collapse
Affiliation(s)
- Ranjan Kumar Singh
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium.,VIB-VUB Center for Structural Biology, Pleinlaan 2, Brussels, 1050, Belgium
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium.,VIB-VUB Center for Structural Biology, Pleinlaan 2, Brussels, 1050, Belgium
| | - Wim Versées
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium.,VIB-VUB Center for Structural Biology, Pleinlaan 2, Brussels, 1050, Belgium
| |
Collapse
|
36
|
The biosynthetic pathway of 2-azahypoxanthine in fairy-ring forming fungus. Sci Rep 2016; 6:39087. [PMID: 27991529 PMCID: PMC5171910 DOI: 10.1038/srep39087] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 11/17/2016] [Indexed: 01/01/2023] Open
Abstract
“Fairy rings” resulting from fungus-stimulated plant growth occur all over the world. In 2010, 2-azahypoxanthine (AHX) from a fungus Lepista sordida was identified as the “fairy” that stimulates plant growth. Furthermore, 2-aza-8-oxohypoxanthine (AOH) was isolated as a common metabolite of AHX in plants, and the endogenous existence of AHX and AOH in plants was proved. The structure of AHX allowed us to hypothesize that AHX was derived from 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). Thus, we performed a feeding experiment that supplied AICAR to L. sordida. Consumption of AICAR and accumulation of AHX were observed after feeding. The mycelia extract had enzymatic activity of adenine/5-aminoimidazole-4-carboxamide phosphoribosyltransferase (APRT). APRT gene of L. sordida revealed its structural characteristics in homology modeling and showed transcriptional enhancement after feeding. These results support that AHX was synthesized from AICAR and AHX biosynthesis was transcriptionally controlled by AICAR, indicating the presence of novel purine metabolic pathway in L. sordida.
Collapse
|
37
|
Leija C, Rijo-Ferreira F, Kinch LN, Grishin NV, Nischan N, Kohler JJ, Hu Z, Phillips MA. Pyrimidine Salvage Enzymes Are Essential for De Novo Biosynthesis of Deoxypyrimidine Nucleotides in Trypanosoma brucei. PLoS Pathog 2016; 12:e1006010. [PMID: 27820863 PMCID: PMC5098729 DOI: 10.1371/journal.ppat.1006010] [Citation(s) in RCA: 21] [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: 08/23/2016] [Accepted: 10/18/2016] [Indexed: 01/17/2023] Open
Abstract
The human pathogenic parasite Trypanosoma brucei possess both de novo and salvage routes for the biosynthesis of pyrimidine nucleotides. Consequently, they do not require salvageable pyrimidines for growth. Thymidine kinase (TK) catalyzes the formation of dTMP and dUMP and is one of several salvage enzymes that appear redundant to the de novo pathway. Surprisingly, we show through analysis of TK conditional null and RNAi cells that TK is essential for growth and for infectivity in a mouse model, and that a catalytically active enzyme is required for its function. Unlike humans, T. brucei and all other kinetoplastids lack dCMP deaminase (DCTD), which provides an alternative route to dUMP formation. Ectopic expression of human DCTD resulted in full rescue of the RNAi growth phenotype and allowed for selection of viable TK null cells. Metabolite profiling by LC-MS/MS revealed a buildup of deoxypyrimidine nucleosides in TK depleted cells. Knockout of cytidine deaminase (CDA), which converts deoxycytidine to deoxyuridine led to thymidine/deoxyuridine auxotrophy. These unexpected results suggested that T. brucei encodes an unidentified 5'-nucleotidase that converts deoxypyrimidine nucleotides to their corresponding nucleosides, leading to their dead-end buildup in TK depleted cells at the expense of dTTP pools. Bioinformatics analysis identified several potential candidate genes that could encode 5'-nucleotidase activity including an HD-domain protein that we show catalyzes dephosphorylation of deoxyribonucleotide 5'-monophosphates. We conclude that TK is essential for synthesis of thymine nucleotides regardless of whether the nucleoside precursors originate from the de novo pathway or through salvage. Reliance on TK in the absence of DCTD may be a shared vulnerability among trypanosomatids and may provide a unique opportunity to selectively target a diverse group of pathogenic single-celled eukaryotes with a single drug.
Collapse
Affiliation(s)
- Christopher Leija
- Department of Pharmacology University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Filipa Rijo-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Lisa N. Kinch
- Department of Biophysics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Nick V. Grishin
- Department of Biophysics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Nicole Nischan
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Jennifer J. Kohler
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Zeping Hu
- Children’s Medical Center Research Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Margaret A. Phillips
- Department of Pharmacology University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| |
Collapse
|
38
|
Crystal structures and inhibition of Trypanosoma brucei hypoxanthine-guanine phosphoribosyltransferase. Sci Rep 2016; 6:35894. [PMID: 27786284 PMCID: PMC5081515 DOI: 10.1038/srep35894] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 10/06/2016] [Indexed: 01/29/2023] Open
Abstract
Human African Trypanosomiasis (HAT) is a life-threatening infectious disease caused by the protozoan parasite, Trypanosoma brucei (Tbr). Due to the debilitating side effects of the current therapeutics and the emergence of resistance to these drugs, new medications for this disease need to be developed. One potential new drug target is 6-oxopurine phosphoribosyltransferase (PRT), an enzyme central to the purine salvage pathway and whose activity is critical for the production of the nucleotides (GMP and IMP) required for DNA/RNA synthesis within this protozoan parasite. Here, the first crystal structures of this enzyme have been determined, these in complex with GMP and IMP and with three acyclic nucleoside phosphonate (ANP) inhibitors. The Ki values for GMP and IMP are 30.5 μM and 77 μM, respectively. Two of the ANPs have Ki values considerably lower than for the nucleotides, 2.3 μM (with guanine as base) and 15.8 μM (with hypoxanthine as base). The crystal structures show that when two of the ANPs bind, they induce an unusual conformation change to the loop where the reaction product, pyrophosphate, is expected to bind. This and other structural differences between the Tbr and human enzymes suggest selective inhibitors for the Tbr enzyme can be designed.
Collapse
|
39
|
Aoki JI, Coelho AC, Muxel SM, Zampieri RA, Sanchez EMR, Nerland AH, Floeter-Winter LM, Cotrim PC. Characterization of a Novel Endoplasmic Reticulum Protein Involved in Tubercidin Resistance in Leishmania major. PLoS Negl Trop Dis 2016; 10:e0004972. [PMID: 27606425 PMCID: PMC5015992 DOI: 10.1371/journal.pntd.0004972] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/11/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Tubercidin (TUB) is a toxic adenosine analog with potential antiparasitic activity against Leishmania, with mechanism of action and resistance that are not completely understood. For understanding the mechanisms of action and identifying the potential metabolic pathways affected by this drug, we employed in this study an overexpression/selection approach using TUB for the identification of potential targets, as well as, drug resistance genes in L. major. Although, TUB is toxic to the mammalian host, these findings can provide evidences for a rational drug design based on purine pathway against leishmaniasis. METHODOLOGY/PRINCIPAL FINDINGS After transfection of a cosmid genomic library into L. major Friedlin (LmjF) parasites and application of the overexpression/selection method, we identified two cosmids (cosTUB1 and cosTU2) containing two different loci capable of conferring significant levels of TUB resistance. In the cosTUB1 contained a gene encoding NUPM1-like protein, which has been previously described as associated with TUB resistance in L. amazonensis. In the cosTUB2 we identified and characterized a gene encoding a 63 kDa protein that we denoted as tubercidin-resistance protein (TRP). Functional analysis revealed that the transfectants were less susceptible to TUB than LmjF parasites or those transfected with the control vector. In addition, the trp mRNA and protein levels in cosTUB2 transfectants were higher than LmjF. TRP immunolocalization revealed that it was co-localized to the endoplasmic reticulum (ER), a cellular compartment with many functions. In silico predictions indicated that TRP contains only a hypothetical transmembrane domain. Thus, it is likely that TRP is a lumen protein involved in multidrug efflux transport that may be involved in the purine metabolic pathway. CONCLUSIONS/SIGNIFICANCE This study demonstrated for the first time that TRP is associated with TUB resistance in Leishmania. The next challenge is to determine how TRP mediates TUB resistance and whether purine metabolism is affected by this protein in the parasite. Finally, these findings may be helpful for the development of alternative anti-leishmanial drugs that target purine pathway.
Collapse
Affiliation(s)
- Juliana Ide Aoki
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Adriano Cappellazzo Coelho
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - Sandra Marcia Muxel
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Ricardo Andrade Zampieri
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | | | | | | | - Paulo Cesar Cotrim
- Instituto de Medicina Tropical, Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| |
Collapse
|
40
|
Freitas-Mesquita AL, Gomes MT, Vieira DP, Paes-Vieira L, Nascimento MTC, Lopes AHCS, Meyer-Fernandes JR. Inhibitory effects promoted by 5'-nucleotides on the ecto-3'-nucleotidase activity of Leishmania amazonensis. Exp Parasitol 2016; 169:111-8. [PMID: 27531705 DOI: 10.1016/j.exppara.2016.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 07/06/2016] [Accepted: 08/09/2016] [Indexed: 12/25/2022]
Abstract
The protozoan parasite Leishmania amazonensis is the etiological agent of cutaneous leishmaniasis. During its life cycle, the flagellated metacyclic promastigote forms are transmitted to vertebrate hosts by sandfly bites, and they develop into amastigotes inside macrophages, where they multiply. L. amazonensis possesses a bifunctional enzyme, called 3'-nucleotidase/nuclease (3'NT/NU), which is able to hydrolyze extracellular 3'-monophosphorylated nucleosides and nucleic acids. 3'NT/NU plays an important role in the generation of extracellular adenosine and has been described as a key enzyme in the acquisition of purines by trypanosomatids. Furthermore, it has been observed that 3'NT/NU also plays a valuable role in the establishment of parasitic infection. In this context, this study aimed to investigate the modulation of the 3'-nucleotidase (3'NT) activity of L. amazonensis by several nucleotides. It was observed that 3'NT activity is inhibited by micromolar concentrations of guanosine and guanine nucleotides. The inhibition promoted by 5'-GMP on the 3'NT activity of L. amazonensis is reversible and uncompetitive because the addition of the inhibitor decreased the kinetic parameters Km and Vmax. Finally, we found that the addition of 5'-GMP is able to reverse the stimulation promoted by 3'-AMP in a macrophage-parasite interaction assay. The determination of compounds that can inhibit the 3'NT activity of Leishmania is very important because this enzyme does not occur in mammals, making it a potential therapeutic target.
Collapse
Affiliation(s)
- Anita Leocadio Freitas-Mesquita
- Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil
| | - Marta T Gomes
- Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil
| | - Danielle P Vieira
- Instituto de Microbiologia Prof. Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Lisvane Paes-Vieira
- Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil
| | - Michelle T C Nascimento
- Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil
| | - Angela H C S Lopes
- Instituto de Microbiologia Prof. Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil.
| |
Collapse
|
41
|
Séguin O, Descoteaux A. Leishmania, the phagosome, and host responses: The journey of a parasite. Cell Immunol 2016; 309:1-6. [PMID: 27531526 DOI: 10.1016/j.cellimm.2016.08.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/25/2016] [Accepted: 08/07/2016] [Indexed: 10/21/2022]
Abstract
Leishmania is the eukaryotic parasite responsible for leishmaniases, a spectrum of diseases that puts at risk roughly 350millions of people in 98 countries according to the Drugs for Neglected Diseases initiative (DNDi). This parasite has a complex life cycle composed of two distinct stages, the promastigote form found in the female sand-fly vector and the amastigote form that replicates in the mammalian host (Teixeira et al., 2013) [1]. To survive, the parasite interacts with its host immune system at multiple levels. In this review, we discuss the nature of those interactions, how they affect the host immune system, and how they affect parasite survival from the very beginning of the life cycle in the vector to its dissemination within the mammalian host.
Collapse
Affiliation(s)
- Olivier Séguin
- INRS-Institut Armand-Frappier and the Center for Host-Parasite Interactions, Laval, Canada
| | - Albert Descoteaux
- INRS-Institut Armand-Frappier and the Center for Host-Parasite Interactions, Laval, Canada.
| |
Collapse
|
42
|
Mycophenolic Acid and Its Derivatives as Potential Chemotherapeutic Agents Targeting Inosine Monophosphate Dehydrogenase in Trypanosoma congolense. Antimicrob Agents Chemother 2016; 60:4391-3. [PMID: 27139487 DOI: 10.1128/aac.02816-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/27/2016] [Indexed: 01/23/2023] Open
Abstract
This study aimed to evaluate the trypanocidal activity of mycophenolic acid (MPA) and its derivatives for Trypanosoma congolense The proliferation of T. congolense was completely inhibited by adding <1 μM MPA and its derivatives. In addition, the IMP dehydrogenase in T. congolense was molecularly characterized as the target of these compounds. The results suggest that MPA and its derivatives have the potential to be new candidates as novel trypanocidal drugs.
Collapse
|
43
|
Trypanosoma evansi contains two auxiliary enzymes of glycolytic metabolism: Phosphoenolpyruvate carboxykinase and pyruvate phosphate dikinase. Exp Parasitol 2016; 165:7-15. [PMID: 26968775 DOI: 10.1016/j.exppara.2016.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 02/11/2016] [Accepted: 03/03/2016] [Indexed: 11/22/2022]
Abstract
Trypanosoma evansi is a monomorphic protist that can infect horses and other animal species of economic importance for man. Like the bloodstream form of the closely related species Trypanosoma brucei, T. evansi depends exclusively on glycolysis for its free-energy generation. In T. evansi as in other kinetoplastid organisms, the enzymes of the major part of the glycolytic pathway are present within organelles called glycosomes, which are authentic but specialized peroxisomes. Since T. evansi does not undergo stage-dependent differentiations, it occurs only as bloodstream forms, it has been assumed that the metabolic pattern of this parasite is identical to that of the bloodstream form of T. brucei. However, we report here the presence of two additional enzymes, phosphoenolpyruvate carboxykinase and PPi-dependent pyruvate phosphate dikinase in T. evansi glycosomes. Their colocalization with glycolytic enzymes within the glycosomes of this parasite has not been reported before. Both enzymes can make use of PEP for contributing to the production of ATP within the organelles. The activity of these enzymes in T. evansi glycosomes drastically changes the model assumed for the oxidation of glucose by this parasite.
Collapse
|
44
|
Hojjat H, Jardim A. The Leishmania donovani peroxin 14 binding domain accommodates a high degeneracy in the pentapeptide motifs present on peroxin 5. Biochim Biophys Acta Gen Subj 2015; 1850:2203-12. [DOI: 10.1016/j.bbagen.2015.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 06/22/2015] [Accepted: 07/21/2015] [Indexed: 12/12/2022]
|
45
|
Dalla Rosa L, Da Silva AS, Oliveira CB, Gressler LT, Arnold CB, Baldissera MD, Sagrillo M, Sangoi M, Moresco R, Mendes RE, Weiss PE, Miletti LC, Monteiro SG. Dose finding of 3′deoxyadenosine and deoxycoformycin for the treatment of Trypanosoma evansi infection: An effective and nontoxic dose. Microb Pathog 2015; 85:21-8. [DOI: 10.1016/j.micpath.2015.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 05/15/2015] [Accepted: 05/24/2015] [Indexed: 10/23/2022]
|
46
|
Li Q, Leija C, Rijo-Ferreira F, Chen J, Cestari I, Stuart K, Tu BP, Phillips MA. GMP synthase is essential for viability and infectivity of Trypanosoma brucei despite a redundant purine salvage pathway. Mol Microbiol 2015; 97:1006-20. [PMID: 26043892 DOI: 10.1111/mmi.13083] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2015] [Indexed: 12/28/2022]
Abstract
The causative agent of human African trypanosomiasis, Trypanosoma brucei, lacks de novo purine biosynthesis and depends on purine salvage from the host. The purine salvage pathway is redundant and contains two routes to guanosine-5'-monophosphate (GMP) formation: conversion from xanthosine-5'-monophosphate (XMP) by GMP synthase (GMPS) or direct salvage of guanine by hypoxanthine-guanine phosphoribosyltransferase (HGPRT). We show recombinant T. brucei GMPS efficiently catalyzes GMP formation. Genetic knockout of GMPS in bloodstream parasites led to depletion of guanine nucleotide pools and was lethal. Growth of gmps null cells was only rescued by supraphysiological guanine concentrations (100 μM) or by expression of an extrachromosomal copy of GMPS. Hypoxanthine was a competitive inhibitor of guanine rescue, consistent with a common uptake/metabolic conversion mechanism. In mice, gmps null parasites were unable to establish an infection demonstrating that GMPS is essential for virulence and that plasma guanine is insufficient to support parasite purine requirements. These data validate GMPS as a potential therapeutic target for treatment of human African trypanosomiasis. The ability to strategically inhibit key metabolic enzymes in the purine pathway unexpectedly bypasses its functional redundancy by exploiting both the nature of pathway flux and the limited nutrient environment of the parasite's extracellular niche.
Collapse
Affiliation(s)
- Qiong Li
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Christopher Leija
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Filipa Rijo-Ferreira
- Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA.,Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Jun Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Igor Cestari
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109-5219, USA
| | - Kenneth Stuart
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109-5219, USA
| | - Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Margaret A Phillips
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| |
Collapse
|
47
|
Structural and Kinetic Characterization of Thymidine Kinase from Leishmania major. PLoS Negl Trop Dis 2015; 9:e0003781. [PMID: 25978379 PMCID: PMC4433323 DOI: 10.1371/journal.pntd.0003781] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/23/2015] [Indexed: 01/17/2023] Open
Abstract
Leishmania spp. is a protozoan parasite and the causative agent of leishmaniasis. Thymidine kinase (TK) catalyses the transfer of the γ-phosphate of ATP to 2’-deoxythymidine (dThd) forming thymidine monophosphate (dTMP). L. major Type II TK (LmTK) has been previously shown to be important for infectivity of the parasite and therefore has potential as a drug target for anti-leishmanial therapy. In this study, we determined the enzymatic properties and the 3D structures of holo forms of the enzyme. LmTK efficiently phosphorylates dThd and dUrd and has high structural homology to TKs from other species. However, it significantly differs in its kinetic properties from Trypanosoma brucei TK since purines are not substrates of the enzyme and dNTPs such as dUTP inhibit LmTK. The enzyme had Km and kcat values for dThd of 1.1 μM and 2.62 s-1 and exhibits cooperative binding for ATP. Additionally, we show that the anti-retroviral prodrug zidovudine (3-azido-3-deoxythymidine, AZT) and 5’-modified dUrd can be readily phosphorylated by LmTK. The production of recombinant enzyme at a level suitable for structural studies was achieved by the construction of C-terminal truncated versions of the enzyme and the use of a baculoviral expression system. The structures of the catalytic core of LmTK in complex with dThd, the negative feedback regulator dTTP and the bi-substrate analogue AP5dT, were determined to 2.74, 3.00 and 2.40 Å, respectively, and provide the structural basis for exclusion of purines and dNTP inhibition. The results will aid the process of rational drug design with LmTK as a potential target for anti-leishmanial drugs. The DNA within the genome of an organism encodes all the information, firstly for reproduction and secondly for translation into proteins—the workhorses of a biological cell. Proteins carry out a host of essential biological activities within the cell. A full understanding of a protein now requires determination of a wide range of its properties in solution in the cell and in vitro in solution, but in addition, its 3D structure usually determined by X-ray crystallography. Leishmania species are a family of protozoan parasites of humans and the causative agent of leishmaniasis, a major health concern in the developing world. Selective inhibition of key enzymes in these parasites is a key route for combating these diseases. We have focused our work on thymidine kinase, an important enzyme from Leishmania major, and a potential target for the development of new drugs. We have carried out kinetic studies of the enzyme’s activity in solution and determined its 3D crystal structure, enabling rational drug design.
Collapse
|
48
|
Pitaluga AN, Moreira MEC, Traub-Csekö YM. A putative role for inosine 5' monophosphate dehydrogenase (IMPDH) in Leishmania amazonensis programmed cell death. Exp Parasitol 2014; 149:32-8. [PMID: 25499513 DOI: 10.1016/j.exppara.2014.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 11/25/2014] [Accepted: 12/04/2014] [Indexed: 11/18/2022]
Abstract
Leishmania amazonensis undergoes apoptosis-like programmed cell death (PCD) under heat shock conditions. We identified a potential role for inosine 5' monophosphate dehydrogenase (IMPDH) in L. amazonensis PCD. Trypanosomatids do not have a "de novo" purine synthesis pathway, relying on the salvage pathway for survival. IMPDH, a key enzyme in the purine nucleotide pathway, is related to cell growth and apoptosis. Since guanine nucleotide depletion triggers cell cycle arrest and apoptosis in several organisms we analyzed the correlation between IMPDH and apoptosis-like death in L. amazonensis. The L. amazonensis IMPDH inhibition effect on PCD was evaluated through gene expression analysis, mitochondrial depolarization and detection of Annexin-V labeled parasites. We demonstrated a down-regulation of impdh expression under heat shock treatment, which mimics the natural mammalian host infection. Also, IMPDH inhibitors ribavirin and mycophenolic acid (MPA) prevented cell growth and generated an apoptosis-like phenotype in sub-populations of L. amazonensis promastigotes. Our results are in accordance with previous results showing that a subpopulation of parasites undergoes apoptosis-like cell death in the nutrient poor environment of the vector gut. Here, we suggest the involvement of purine metabolism in previously observed apoptosis-like cell death during Leishmania infection.
Collapse
Affiliation(s)
- A N Pitaluga
- Laboratório de Biologia Molecular de Parasitas e Vetores, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil.
| | - M E C Moreira
- Divisão de Medicina Experimental, Instituto Nacional de Câncer, Rio de Janeiro, Brazil
| | - Y M Traub-Csekö
- Laboratório de Biologia Molecular de Parasitas e Vetores, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil
| |
Collapse
|
49
|
3'-nucleotidase/nuclease activity allows Leishmania parasites to escape killing by neutrophil extracellular traps. Infect Immun 2014; 82:1732-40. [PMID: 24516114 DOI: 10.1128/iai.01232-13] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Leishmaniasis is a widespread neglected tropical disease caused by parasites of the Leishmania genus. These parasites express the enzyme 3'-nucleotidase/nuclease (3'NT/NU), which has been described to be involved in parasite nutrition and infection. Bacteria that express nucleases escape the toxic effects of neutrophil extracellular traps (NETs). Hence, we investigated the role of 3'NT/NU in Leishmania survival of NET-mediated killing. Promastigotes of Leishmania infantum were cultured in high-phosphate (HP) or low-phosphate (LP) medium to modulate nuclease activity. We compared the survival of the two different groups of Leishmania during interaction with human neutrophils, assessing the role of neutrophil extracellular traps. As previously reported, we detected higher nuclease activity in parasites cultured in LP medium. Both LP and HP promastigotes were capable of inducing the release of neutrophil extracellular traps from human neutrophils in a dose- and time-dependent manner. LP parasites had 2.4 times more survival than HP promastigotes. NET disruption was prevented by the treatment of the parasites with ammonium tetrathiomolybdate (TTM), a 3'NT/NU inhibitor. Inhibition of 3'NT/NU by 3'-AMP, 5'-GMP, or TTM decreased promastigote survival upon interaction with neutrophils. Our results show that Leishmania infantum induces NET release and that promastigotes can escape NET-mediated killing by 3'-nucleotidase/nuclease activity, thus ascribing a new function to this enzyme.
Collapse
|
50
|
Valdés R, Elferich J, Shinde U, Landfear SM. Identification of the intracellular gate for a member of the equilibrative nucleoside transporter (ENT) family. J Biol Chem 2014; 289:8799-809. [PMID: 24497645 DOI: 10.1074/jbc.m113.546960] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Equilibrative nucleoside transporters of the SLC29 family play important roles in many physiological and pharmacological processes, including import of drugs for treatment of cancer, AIDS, cardiovascular, and parasitic diseases. However, no crystal structure is available for any member of this family. In previous studies we generated a computational model of the Leishmania donovani nucleoside transporter 1.1 (LdNT1.1) that captured this permease in the outward-closed conformation, and we identified the extracellular gate. In the present study we have modeled the inward-closed conformation of LdNT1.1 using the crystal structure of the Escherichia coli fucose transporter FucP and have identified four transmembrane helices whose ends close to form a predicted intracellular gate. We have tested this prediction by site-directed mutagenesis of relevant helix residues and by cross-linking of introduced cysteine pairs. The results are consistent with the predictions of the computational model and suggest that a similarly constituted gate operates in other members of the equilibrative nucleoside transporter family.
Collapse
Affiliation(s)
- Raquel Valdés
- From the Departments of Molecular Microbiology and Immunology and
| | | | | | | |
Collapse
|