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de Souza-Maciel E, Carvalho-Kelly LF, Freitas-Mesquita AL, Meyer-Fernandes JR. The ecto-3'-nucleotidase activity of Acanthamoeba castellanii trophozoites increases their adhesion to host cells through the generation of extracellular adenosine. Eur J Protistol 2024; 94:126086. [PMID: 38688045 DOI: 10.1016/j.ejop.2024.126086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/24/2024] [Accepted: 04/24/2024] [Indexed: 05/02/2024]
Abstract
Acanthamoeba castellanii, a free-living amoeba, can be pathogenic to humans causing a corneal infection named Acanthamoeba keratitis (AK). The mannose-binding protein (MBP) is well established as the major factor related to Acanthamoeba pathogenesis. However, additional factors that participate in the adhesion process and protect trophozoites from cytolytic effects caused by host immune responses remain unknown. Ectonucleotidases, including 3'-nucleotidase/nuclease (3'-NT/NU), a bifunctional enzyme that was recently reported in A. castellanii, are frequently related to the establishment of parasitic infections. We verified that trophozoites can hydrolyze 3'-AMP, and this activity is similar to that observed in other protists. The addition of 3'-AMP increases the adhesion of trophozoites to LLC-MK2 epithelial cells, and this stimulation is completely reversed by DTT, an inhibitor of ecto-3'-nucleotidase activity. Lesions in corneal cells caused by AK infection may elevate the extracellular level of 3'-AMP. We believe that ecto-3'-nucleotidase activity can modulate the host immune response, thus facilitating the establishment of parasitic infection. This activity results from the generation of extracellular adenosine, which can bind to purinergic receptors present in host immune cells. Positive feedback may occur in this cascade of events once the ecto-3'-nucleotidase activity of trophozoites is increased by the adhesion of trophozoites to LLC-MK2 cells.
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Carvalho-Kelly LF, Freitas-Mesquita AL, Nascimento MTC, Dick CF, de Souza-Maciel E, Rochael NC, Saraiva EM, Meyer-Fernandes JR. Acanthamoeba castellanii trophozoites escape killing by neutrophil extracellular traps using their 3'-nucleotidase/nuclease activity. Eur J Protistol 2023; 91:126032. [PMID: 37948889 DOI: 10.1016/j.ejop.2023.126032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023]
Abstract
Acanthamoeba castellanii is a free-living amoeba that acts as an opportunistic pathogen for humans and is the pathogenic agent of Acanthamoeba keratitis (AK). A. castellanii may present as proliferative and infective trophozoites or as resistant cysts during their life cycle. The immune response against AK is still poorly explored; however, it is well established that macrophages and neutrophils play essential roles in controlling corneal infection during the disease outcome. The release of NETs is one of the innate immune strategies to prevent parasite infection, especially when neutrophils interact with microorganisms that are too large to be phagocytosed, which is the case for amoeba species. The present work demonstrated that A. castellanii trophozoites can trigger NET formation upon in vitro interaction with neutrophils. Using DNase as a control, we observed increased parasite survival after coinciding with neutrophils, which may be correlated with NET degradation. Indeed, A. castellanii trophozoites degrade the NET DNA scaffold. Molecular analysis confirmed the occurrence of a 3'-nucleotidase/nuclease (3'-NT/NU) in the A. castellanii genome. We also demonstrated that trophozoites exhibit significantly higher 3'-NT/NU activity than cysts, which cannot trigger NET release. Considering that previous studies indicated the pathological role of 3'-NT-/NU in parasite infection, we suggest that this enzyme may act as the mechanism of escape of A. castellanii trophozoites from NETs.
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Affiliation(s)
| | | | - Michelle T C Nascimento
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), UFRJ, Rio de Janeiro, RJ, Brazil; Instituto de Microbiologia Paulo de Góes (IMPG), UFRJ, Rio de Janeiro, RJ, Brazil
| | - Claudia F Dick
- Instituto de Biofísica Carlos Chagas Filho (IBCCF), UFRJ, Rio de Janeiro, RJ, Brazil
| | | | - Natalia C Rochael
- Instituto de Microbiologia Paulo de Góes (IMPG), UFRJ, Rio de Janeiro, RJ, Brazil
| | - Elvira M Saraiva
- Instituto de Microbiologia Paulo de Góes (IMPG), UFRJ, Rio de Janeiro, RJ, Brazil
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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.
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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
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Li J, Zhang X, Fan WY, Yao MC, Sheng GP. Dissolved organic matter dominating the photodegradation of free DNA bases in aquatic environments. WATER RESEARCH 2020; 179:115885. [PMID: 32402864 DOI: 10.1016/j.watres.2020.115885] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/13/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
Free DNA bases are widely present in the environments, and can be utilized by bacteria for their nucleic acids synthesis or as nutrition sources. In sunlit natural waters, these free bases probably undergo photodegradation which would change the bioavailable bases contents. Though the photodegradation of DNA has been investigated, the photodegradation behaviors of free bases may be quite different from those of DNA-confined bases in consideration of their different chemical environments. Herein, the photodegradation of four free bases (guanine, adenine, thymine and cytosine) was investigated. Results show that direct photodegradation of free bases in phosphate buffer caused by UV was slow. However, the photodegradation of these free bases were greatly enhanced in dissolved organic matter (DOM) solution. In the presence of 10-50 mg/L DOM, the photodegradation rates of free bases were increased by 1.85-14.6 times compared to the controls without DOM. DOM could result in indirect photodegradation by producing hydroxyl radical (•OH) and singlet oxygen (1O2) under irradiation, and this indirect photodegradation enhanced and dominated the free bases photodegradation. The •OH was involved in all four bases photodegradation, while the 1O2 only participated in guanine photodegradation. In phosphate buffer, the fastest photodegradation bases were pyrimidine, however, guanine became the fastest photodegradation base in DOM solution due to the selective oxidation of guanine by 1O2. In summary, DOM may be a determinant for free bases photodegradation in natural waters and thereby deeply influence free bases fates in aquatic environments.
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Affiliation(s)
- Jing Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science and Technology of China, Hefei, 230026, China
| | - Xin Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science and Technology of China, Hefei, 230026, China.
| | - Wen-Yuan Fan
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science and Technology of China, Hefei, 230026, China
| | - Mu-Cen Yao
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Guo-Ping Sheng
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science and Technology of China, Hefei, 230026, China.
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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.
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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.
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Transcutaneous immunization using SLA or rLACK skews the immune response towards a Th1 profile but fails to protect BALB/c mice against a Leishmania major challenge. Vaccine 2019; 37:516-523. [DOI: 10.1016/j.vaccine.2018.11.052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/12/2018] [Accepted: 11/17/2018] [Indexed: 11/21/2022]
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Jardim A, Hardie DB, Boitz J, Borchers CH. Proteomic Profiling of Leishmania donovani Promastigote Subcellular Organelles. J Proteome Res 2018; 17:1194-1215. [PMID: 29332401 DOI: 10.1021/acs.jproteome.7b00817] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To facilitate a greater understanding of the biological processes in the medically important Leishmania donovani parasite, a combination of differential and density-gradient ultracentrifugation techniques were used to achieve a comprehensive subcellular fractionation of the promastigote stage. An in-depth label-free proteomic LC-MS/MS analysis of the density gradients resulted in the identification of ∼50% of the Leishmania proteome (3883 proteins detected), which included ∼645 integral membrane proteins and 1737 uncharacterized proteins. Clustering and subcellular localization of proteins was based on a subset of training Leishmania proteins with known subcellular localizations that had been determined using biochemical, confocal microscopy, or immunoelectron microscopy approaches. This subcellular map will be a valuable resource that will help dissect the cell biology and metabolic processes associated with specific organelles of Leishmania and related kinetoplastids.
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Affiliation(s)
- Armando Jardim
- Institute of Parasitology, Macdonald Campus, McGill University , 21111 Lakeshore Road, Saine-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Darryl B Hardie
- University of Victoria -Genome British Columbia Proteomics Centre , #3101-4464 Markham Street, Vancouver Island Technology Park, Victoria, British Columbia V8Z7X8, Canada
| | - Jan Boitz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University , Portland, Oregon 97239, United States
| | - Christoph H Borchers
- University of Victoria -Genome British Columbia Proteomics Centre , #3101-4464 Markham Street, Vancouver Island Technology Park, Victoria, British Columbia V8Z7X8, Canada.,Department of Biochemistry and Biophysics, University of North Carolina , 120 Mason Farm Road, Campus Box 7260 Third Floor, Genetic Medicine Building, Chapel Hill, North Carolina 27599, United States.,Department of Biochemistry and Microbiology, University of Victoria , Petch Building, Room 270d, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada.,Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University , 3755 Côte Ste-Catherine Road, Montreal, Quebec H3T 1E2, Canada.,Proteomics Centre, Segal Cancer Centre, Lady Davis Institute, Jewish General Hospital, McGill University , 3755 Côte Ste-Catherine Road, Montreal, Quebec H3T 1E2, Canada
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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.
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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.
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Magnesium-Dependent Ecto-ATP Diphosphohydrolase Activity in Leishmania donovani. Curr Microbiol 2016; 73:811-819. [PMID: 27589852 DOI: 10.1007/s00284-016-1130-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
Abstract
In this work, we have described the expression of ecto-ATPDase on the external surface of Leishmania donovani. This enzyme has the ability to hydrolyze extracellular ATP. There is a low level of ATP hydrolysis in the absence of divalent cation 2.5 ± 0.51 nM Pi 107 cells/h which shows the divalent cation-dependent activity of this enzyme in the intact parasite. However, MgCl2 stimulated the ATP hydrolysis to a greater extent compared with CaCl2 and ZnCl2. This activity was also observed when replaced by MnCl2. The Mg-dependent ecto-ATPase activity was 46.58 ± 6.248 nM Pi 107 cells/h. The apparent K m for ATP was 5.76 mM. Since Leishmania also possesses acid phosphatase activity and to discard the possibility that the observed ATP hydrolysis was due to acid phosphatase, the effect of pH was examined. In the pH range 6.0-9.0, in which the cells were viable, the phosphatase activity decreased while ATPase activity increased. To show that the observed ATP hydrolysis was not due to phosphatase or nucleotidase activity, certain inhibitors for these enzymes were tested. Vandate and NaF inhibited the phosphatase activity; Ammonium molybdate inhibited 5'-nucleotidase activity, but these inhibitors did not inhibit the observed ATP hydrolysis. However, when ADP was used as a substrate, there was no inhibition of ATP hydrolysis showing the possibility of ATP diphosphohydrolase activity. To confirm that this Mg-dependent ATPase activity is an ecto-ATPase activity, we used an impermeable inhibitor, 4,4'-diisothiocyanostilbene 2,-2'-disulfonic acid, as well as suramin, an antagonist of P2-purinoceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg2+-dependent ATPase activity in a dose-dependent manner. The presence of L. donovani E-NTPDase activity was demonstrated using antibodies against NTPDase by Western blotting and flow cytometry. The presence of Mg2+-dependent ATP diphosphohydrolase activity on the surface of L. donovani modulates the nucleotide concentration and protects the parasite from the lytic effects of the nucleotides mainly ATP. Ecto-ATPDase from L. donovani may be further characterized as a good antigen and as a target for immunodiagnosis and drug development, respectively.
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Freitas-Mesquita AL, Meyer-Fernandes JR. Ecto-nucleotidases and Ecto-phosphatases from Leishmania and Trypanosoma parasites. Subcell Biochem 2014; 74:217-252. [PMID: 24264248 DOI: 10.1007/978-94-007-7305-9_10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Ecto-enzymes can be defined as membrane-bound proteins that have their active site facing the extracellular millieu. In trypanosomatids, the physiological roles of these enzymes remain to be completed elucidated; however, many important events have already been related to them, such as the survival of parasites during their complex life cycle and the successful establishment of host infection. This chapter focuses on two remarkable classes of ecto-enzymes: ecto-nucleotidases and ecto-phosphatases, summarizing their occurrence and possible physiological roles in Leishmania and Trypanosoma genera. Ecto-nucleotidases are characterized by their ability to hydrolyze extracellular nucleotides, playing an important role in purinergic signaling. By the action of these ecto-enzymes, parasites are capable of modulating the host immune system, which leads to a successful parasite infection. Furthermore, ecto-nucleotidases are also involved in the purine salvage pathway, acting in the generation of nucleosides that are able to cross plasma membrane via specialized transporters. Another important ecto-enzyme present in a vast number of pathogenic organisms is the ecto-phosphatase. These enzymes are able to hydrolyze extracellular phosphorylated substrates, releasing free inorganic phosphate that can be internalized by the cell, crossing the plasma membrane through a Pi-transporter. Ecto-phosphatases are also involved in the invasion and survival of parasite in the host cells. Several alternative functions have been suggested for these enzymes in parasites, such as participation in their proliferation, differentiation, nutrition and protection. In this context, the present chapter provides an overview of recent discoveries related to the occurrence of ecto-nucleotidase and ecto-phosphatase activities in Leishmania and Trypanosoma parasites.
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Paletta-Silva R, Vieira-Bernardo R, Cosentino-Gomes D, Meyer-Fernandes JR. Leishmania amazonensis: Inhibition of 3′-nucleotidase activity by Cu2+ ions. Exp Parasitol 2012; 131:63-8. [DOI: 10.1016/j.exppara.2012.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 02/28/2012] [Accepted: 03/01/2012] [Indexed: 11/17/2022]
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Paletta-Silva R, Meyer-Fernandes JR. Adenosine and immune imbalance in visceral leishmaniasis: the possible role of ectonucleotidases. J Trop Med 2011; 2012:650874. [PMID: 22007242 PMCID: PMC3189589 DOI: 10.1155/2012/650874] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 07/31/2011] [Accepted: 08/10/2011] [Indexed: 12/20/2022] Open
Abstract
Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is responsible for most Leishmania-associated deaths. VL represents a serious public health problem that affects many countries. The immune response in leishmaniasis is very complex and is poorly understood. The Th1 versus Th2 paradigm does not appear to be so clear in visceral leishmaniasis, suggesting that other immunosuppressive or immune-evasion mechanisms contribute to the pathogenesis of VL. It has been demonstrated that generation of adenosine, a potent endogenous immunosuppressant, by extracellular enzymes capable to hydrolyze adenosine tri-nucleotide (ATP) at the site of infection, can lead to immune impairment and contribute to leishmaniasis progression. In this regard, this paper discusses the unique features in VL immunopathogenesis, including a possible role for ectonucleotidases in leishmaniasis.
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Affiliation(s)
- Rafael Paletta-Silva
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem (INCTBEB), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem (INCTBEB), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ), Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
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Leishmania amazonensis: characterization of an ecto-3'-nucleotidase activity and its possible role in virulence. Exp Parasitol 2011; 129:277-83. [PMID: 21827749 DOI: 10.1016/j.exppara.2011.07.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 07/07/2011] [Accepted: 07/14/2011] [Indexed: 11/22/2022]
Abstract
Ecto-3'-nucleotidase/nuclease (3'NT/NU) is a membrane-bound enzyme that plays a key role in the nutrition of Leishmania sp. protozoan parasites. This enzyme generates nucleosides via hydrolyzes of 3'mononucleotides and nucleic acids, which enter the cell by specific transporters. In this work, we identify and characterize Leishmania amazonensis ecto-3'-nucleotidase activity (La3'-nucleotidase), report ammonium tetrathiomolybdate (TTM) as a novel La3'-nucleotidase inhibitor and approach the possible involvement of ecto-3'-nucleotidase in cellular adhesion. La3'-nucleotidase presented characteristics similar to those reported for the class I single-strand nuclease family; a molecular weight of approximately 40 kDa and optimum activity in an alkaline pH range were observed. Although it is conserved among the genus, La3'-nucleotidase displays different kinetic properties; it can be inhibited by vanadate, molybdate and Cu(2+) ions. Interestingly, ecto-3'-nucleotidase activity is 60-fold higher than that of ecto-5'-nucleotidase in L. amazonensis. Additionally, ecto-3'-nucleotidase activity is two-fold higher in virulent L. amazonensis cells than in avirulent ones. Notably, macrophage-parasite attachment/invasion was increased by 400% in the presence of adenosine 3'-monophosphate (3'AMP); however, this effect was reverted by TTM treatment. We believe that La3'-nucleotidase may play a significant role in the generation of adenosine, which may contribute to mammalian host immune response impairment and establishment of infection.
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Vieira DP, Paletta-Silva R, Saraiva EM, Lopes AH, Meyer-Fernandes JR. Leishmania chagasi: An ecto-3′-nucleotidase activity modulated by inorganic phosphate and its possible involvement in parasite–macrophage interaction. Exp Parasitol 2011; 127:702-7. [DOI: 10.1016/j.exppara.2010.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 09/03/2010] [Accepted: 11/10/2010] [Indexed: 01/22/2023]
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