1
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Lacerda-Abreu MA, Meyer-Fernandes JR. Elevated extracellular inorganic phosphate inhibits ecto-phosphatase activity in breast cancer cells: Regulation by hydrogen peroxide. Cell Biol Int 2024; 48:162-173. [PMID: 37818706 DOI: 10.1002/cbin.12095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 09/18/2023] [Accepted: 09/30/2023] [Indexed: 10/12/2023]
Abstract
For cells to obtain inorganic phosphate, ectoenzymes in the plasma membrane, which contain a catalytic site facing the extracellular environment, hydrolyze phosphorylated molecules. In this study, we show that increased Pi levels in the extracellular environment promote a decrease in ecto-phosphatase activity, which is associated with Pi-induced oxidative stress. High levels of Pi inhibit ecto-phosphatase because Pi generates H2 O2 . Ecto-phosphatase activity is inhibited by H2 O2 , and this inhibition is selective for phospho-tyrosine hydrolysis. Additionally, it is shown that the mechanism of inhibition of ecto-phosphatase activity involves lipid peroxidation. In addition, the inhibition of ecto-phosphatase activity by H2 O2 is irreversible. These findings have new implications for understanding ecto-phosphatase regulation in the tumor microenvironment. H2 O2 stimulated by high Pi inhibits ecto-phosphatase activity to prevent excessive accumulation of extracellular Pi, functioning as a regulatory mechanism of Pi variations in the tumor microenvironment.
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Affiliation(s)
- Marco A Lacerda-Abreu
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - José R Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
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2
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Dick CF, Alcantara CL, Carvalho-Kelly LF, Lacerda-Abreu MA, Cunha-E-Silva NL, Meyer-Fernandes JR, Vieyra A. Iron Uptake Controls Trypanosoma cruzi Metabolic Shift and Cell Proliferation. Antioxidants (Basel) 2023; 12:antiox12050984. [PMID: 37237850 DOI: 10.3390/antiox12050984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/18/2023] [Accepted: 04/20/2023] [Indexed: 05/28/2023] Open
Abstract
(1) Background: Ionic transport in Trypanosoma cruzi is the object of intense studies. T. cruzi expresses a Fe-reductase (TcFR) and a Fe transporter (TcIT). We investigated the effect of Fe depletion and Fe supplementation on different structures and functions of T. cruzi epimastigotes in culture. (2) Methods: We investigated growth and metacyclogenesis, variations of intracellular Fe, endocytosis of transferrin, hemoglobin, and albumin by cell cytometry, structural changes of organelles by transmission electron microscopy, O2 consumption by oximetry, mitochondrial membrane potential measuring JC-1 fluorescence at different wavelengths, intracellular ATP by bioluminescence, succinate-cytochrome c oxidoreductase following reduction of ferricytochrome c, production of H2O2 following oxidation of the Amplex® red probe, superoxide dismutase (SOD) activity following the reduction of nitroblue tetrazolium, expression of SOD, elements of the protein kinase A (PKA) signaling, TcFR and TcIT by quantitative PCR, PKA activity by luminescence, glyceraldehyde-3-phosphate dehydrogenase abundance and activity by Western blotting and NAD+ reduction, and glucokinase activity recording NADP+ reduction. (3) Results: Fe depletion increased oxidative stress, inhibited mitochondrial function and ATP formation, increased lipid accumulation in the reservosomes, and inhibited differentiation toward trypomastigotes, with the simultaneous metabolic shift from respiration to glycolysis. (4) Conclusion: The processes modulated for ionic Fe provide energy for the T. cruzi life cycle and the propagation of Chagas disease.
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Affiliation(s)
- Claudia F Dick
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro/CENABIO, Rio de Janeiro 21941-902, RJ, Brazil
| | - Carolina L Alcantara
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro/CENABIO, Rio de Janeiro 21941-902, RJ, Brazil
| | - Luiz F Carvalho-Kelly
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
| | - Marco Antonio Lacerda-Abreu
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
| | - Narcisa L Cunha-E-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro/CENABIO, Rio de Janeiro 21941-902, RJ, Brazil
| | - José R Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
| | - Adalberto Vieyra
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro/CENABIO, Rio de Janeiro 21941-902, RJ, Brazil
- Programa de Pós-Graduação em Biomedicina Translacional /BIOTRANS, Universidade do Grande Rio, Duque de Caxias 25071-202, RJ, Brazil
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3
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Saraiva FMS, Cosentino-Gomes D, Inacio JDF, Almeida-Amaral EE, Louzada-Neto O, Rossini A, Nogueira NP, Meyer-Fernandes JR, Paes MC. Hypoxia Effects on Trypanosoma cruzi Epimastigotes Proliferation, Differentiation, and Energy Metabolism. Pathogens 2022; 11:pathogens11080897. [PMID: 36015018 PMCID: PMC9416468 DOI: 10.3390/pathogens11080897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/21/2022] [Accepted: 07/24/2022] [Indexed: 11/18/2022] Open
Abstract
Trypanosoma cruzi, the causative agent of Chagas disease, faces changes in redox status and nutritional availability during its life cycle. However, the influence of oxygen fluctuation upon the biology of T. cruzi is unclear. The present work investigated the response of T. cruzi epimastigotes to hypoxia. The parasites showed an adaptation to the hypoxic condition, presenting an increase in proliferation and a reduction in metacyclogenesis. Additionally, parasites cultured in hypoxia produced more reactive oxygen species (ROS) compared to parasites cultured in normoxia. The analyses of the mitochondrial physiology demonstrated that hypoxic condition induced a decrease in both oxidative phosphorylation and mitochondrial membrane potential (ΔΨm) in epimastigotes. In spite of that, ATP levels of parasites cultivated in hypoxia increased. The hypoxic condition also increased the expression of the hexokinase and NADH fumarate reductase genes and reduced NAD(P)H, suggesting that this increase in ATP levels of hypoxia-challenged parasites was a consequence of increased glycolysis and fermentation pathways. Taken together, our results suggest that decreased oxygen levels trigger a shift in the bioenergetic metabolism of T. cruzi epimastigotes, favoring ROS production and fermentation to sustain ATP production, allowing the parasite to survive and proliferate in the insect vector.
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Affiliation(s)
- Francis M. S. Saraiva
- Trypanosomatids and Vectors Interaction Laboratory, Department of Biochemistry, Roberto Alcantara Gomes Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro 20550-013, Brazil
| | - Daniela Cosentino-Gomes
- Institute of Medical Biochemistry Leopoldo De Meis, Center for Health Sciences, Federal University of Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Job D. F. Inacio
- Tripanosomatide Biochemistry Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Manguinhos, Rio de Janeiro 21040-900, Brazil
| | - Elmo E. Almeida-Amaral
- Tripanosomatide Biochemistry Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Manguinhos, Rio de Janeiro 21040-900, Brazil
| | - Orlando Louzada-Neto
- Laboratory of Toxicology and Molecular Biology, Department of Biochemistry, IBRAG- UERJ, Rio de Janeiro 20511-010, Brazil
| | - Ana Rossini
- Laboratory of Toxicology and Molecular Biology, Department of Biochemistry, IBRAG- UERJ, Rio de Janeiro 20511-010, Brazil
| | - Natália P. Nogueira
- Trypanosomatids and Vectors Interaction Laboratory, Department of Biochemistry, Roberto Alcantara Gomes Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro 20550-013, Brazil
- National Institute of Science and Technology—Molecular Entomology (INCT-EM), Brasília 70000-000, Brazil
| | - José R. Meyer-Fernandes
- Institute of Medical Biochemistry Leopoldo De Meis, Center for Health Sciences, Federal University of Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Marcia C. Paes
- Trypanosomatids and Vectors Interaction Laboratory, Department of Biochemistry, Roberto Alcantara Gomes Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro 20550-013, Brazil
- National Institute of Science and Technology—Molecular Entomology (INCT-EM), Brasília 70000-000, Brazil
- Correspondence:
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4
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Dick CF, Rocco-Machado N, Dos-Santos ALA, Carvalho-Kelly LF, Alcantara CL, Cunha-E-Silva NL, Meyer-Fernandes JR, Vieyra A. An Iron Transporter Is Involved in Iron Homeostasis, Energy Metabolism, Oxidative Stress, and Metacyclogenesis in Trypanosoma cruzi. Front Cell Infect Microbiol 2022; 11:789401. [PMID: 35083166 PMCID: PMC8785980 DOI: 10.3389/fcimb.2021.789401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/06/2021] [Indexed: 11/29/2022] Open
Abstract
The parasite Trypanosoma cruzi causes Chagas’ disease; both heme and ionic Fe are required for its optimal growth, differentiation, and invasion. Fe is an essential cofactor in many metabolic pathways. Fe is also harmful due to catalyzing the formation of reactive O2 species; for this reason, all living systems develop mechanisms to control the uptake, metabolism, and storage of Fe. However, there is limited information available on Fe uptake by T. cruzi. Here, we identified a putative 39-kDa Fe transporter in T. cruzi genome, TcIT, homologous to the Fe transporter in Leishmania amazonensis and Arabidopsis thaliana. Epimastigotes grown in Fe-depleted medium have increased TcIT transcription compared with controls grown in regular medium. Intracellular Fe concentration in cells maintained in Fe-depleted medium is lower than in controls, and there is a lower O2 consumption. Epimastigotes overexpressing TcIT, which was encountered in the parasite plasma membrane, have high intracellular Fe content, high O2 consumption—especially in phosphorylating conditions, high intracellular ATP, very high H2O2 production, and stimulated transition to trypomastigotes. The investigation of the mechanisms of Fe transport at the cellular and molecular levels will assist in elucidating Fe metabolism in T. cruzi and the involvement of its transport in the differentiation from epimastigotes to trypomastigotes, virulence, and maintenance/progression of the infection.
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Affiliation(s)
- Claudia F Dick
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathália Rocco-Machado
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - André L A Dos-Santos
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiz F Carvalho-Kelly
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carolina L Alcantara
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Narcisa L Cunha-E-Silva
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - José R Meyer-Fernandes
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adalberto Vieyra
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Graduate Program in Translational Biomedicine/BIOTRANS, Unigranrio University, Duque de Caxias, Brazil
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5
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Lacerda-Abreu MA, Russo-Abrahão T, Leite Tenório Aguiar R, Monteiro RDQ, Rumjanek FD, Meyer-Fernandes JR. Ectophosphatase activity in the triple-negative breast cancer cell line MDA-MB-231. Cell Biol Int 2020; 45:411-421. [PMID: 33140880 DOI: 10.1002/cbin.11497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 10/06/2020] [Accepted: 10/31/2020] [Indexed: 02/06/2023]
Abstract
Breast cancer is one of the most common cancers in the female population worldwide, and its development is thought to be associated with genetic mutations that lead to uncontrolled and accelerated growth of breast cells. This abnormal behavior requires extra energy, and indeed, tumor cells display a rewired energy metabolism compared to normal breast cells. Inorganic phosphate (Pi) is a glycolytic substrate of glyceraldehyde-3-phosphate dehydrogenase and has an important role in cancer cell proliferation. For cells to obtain Pi, ectoenzymes in the plasma membrane with their catalytic site facing the extracellular environment can hydrolyze phosphorylated molecules, and this is an initial and possibly limiting step for the uptake of Pi by carriers that behave as adjuvants in the process of energy harvesting and thus partially contributes to tumor energy requirements. In this study, the activity of an ectophosphatase in MDA-MB-231 cells was biochemically characterized, and the results showed that the activity of this enzyme was higher in the acidic pH range and that the enzyme had a Km = 4.5 ± 0.5 mM para-nitrophenylphosphate and a Vmax = 2280 ± 158 nM × h-1 × mg protein-1 . In addition, classical acid phosphatase inhibitors, including sodium orthovanadate, decreased enzymatic activity. Sodium orthovanadate was able to inhibit ectophosphatase activity while also inhibiting cell proliferation, adhesion, and migration, which are important processes in tumor progression, especially in metastatic breast cancer MDA-MB-231 cells that have higher ectophosphatase activity than MCF-7 and MCF-10 breast cells.
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Affiliation(s)
- Marco A Lacerda-Abreu
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil
| | - Thais Russo-Abrahão
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil
| | - Raíssa Leite Tenório Aguiar
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil
| | - Robson de Queiroz Monteiro
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil
| | - Franklin D Rumjanek
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil
| | - José R Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, State of Rio de Janeiro, Brazil
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6
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Fernandes ACS, Soares DC, Neves RFC, Koeller CM, Heise N, Adade CM, Frases S, Meyer-Fernandes JR, Saraiva EM, Souto-Padrón T. Endocytosis and Exocytosis in Leishmania amazonensis Are Modulated by Bromoenol Lactone. Front Cell Infect Microbiol 2020; 10:39. [PMID: 32117812 PMCID: PMC7020749 DOI: 10.3389/fcimb.2020.00039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/21/2020] [Indexed: 12/15/2022] Open
Abstract
In the protozoan pathogen Leishmania, endocytosis, and exocytosis occur mainly in the small area of the flagellar pocket membrane, which makes this parasite an interesting model of strikingly polarized internalization and secretion. Moreover, little is known about vesicle recognition and fusion mechanisms, which are essential for both endo/exocytosis in this parasite. In other cell types, vesicle fusion events require the activity of phospholipase A2 (PLA2), including Ca2+-independent iPLA2 and soluble, Ca2+-dependent sPLA2. Here, we studied the role of bromoenol lactone (BEL) inhibition of endo/exocytosis in promastigotes of Leishmania amazonensis. PLA2 activities were assayed in intact parasites, in whole conditioned media, and in soluble and extracellular vesicles (EVs) conditioned media fractions. BEL did not affect the viability of promastigotes, but reduced the differentiation into metacyclic forms. Intact parasites and EVs had BEL-sensitive iPLA2 activity. BEL treatment reduced total EVs secretion, as evidenced by reduced total protein concentration, as well as its size distribution and vesicles in the flagellar pocket of treated parasites as observed by TEM. Membrane proteins, such as acid phosphatases and GP63, became concentrated in the cytoplasm, mainly in multivesicular tubules of the endocytic pathway. BEL also prevented the endocytosis of BSA, transferrin and ConA, with the accumulation of these markers in the flagellar pocket. These results suggested that the activity inhibited by BEL, which is one of the irreversible inhibitors of iPLA2, is required for both endocytosis and exocytosis in promastigotes of L. amazonensis.
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Affiliation(s)
- Anne C S Fernandes
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Deivid C Soares
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Roberta F C Neves
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carolina M Koeller
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Norton Heise
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Camila M Adade
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - José R Meyer-Fernandes
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil.,Centro de Ciências da Saúde, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elvira M Saraiva
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thaïs Souto-Padrón
- Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
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7
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Rocco-Machado N, Cosentino-Gomes D, Nascimento MT, Paes-Vieira L, Khan YA, Mittra B, Andrews NW, Meyer-Fernandes JR. Leishmania amazonensis ferric iron reductase (LFR1) is a bifunctional enzyme: Unveiling a NADPH oxidase activity. Free Radic Biol Med 2019; 143:341-353. [PMID: 31446054 DOI: 10.1016/j.freeradbiomed.2019.08.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 08/21/2019] [Indexed: 01/26/2023]
Abstract
Leishmania amazonensis is one of leishmaniasis' causative agents, a disease that has no cure and leads to the appearance of cutaneous lesions. Recently, our group showed that heme activates a Na+/K+ ATPase in these parasites through a signaling cascade involving hydrogen peroxide (H2O2) generation. Heme has a pro-oxidant activity and signaling capacity, but the mechanism by which this molecule increases H2O2 levels in L. amazonensis has not been elucidated. Here we investigated the source of H2O2 stimulated by heme, ruling out the participation of mitochondria and raising the possibility of a role for a NADPH oxidase (Nox) activity. Despite the absence of a classical Nox sequence in trypanosomatid genomes, L. amazonensis expresses a surface ferric iron reductase (LFR1). Interestingly, Nox enzymes are thought to have evolved from ferric iron reductases because they share same core domain and are very similar in structure. The main difference is that Nox catalyses electron flow from NADPH to oxygen, generating reactive oxygen species (ROS), while ferric iron reductase promotes electron flow to ferric iron, generating ferrous iron. Using L. amazonensis overexpressing or knockout for LFR1 and heterologous expression of LFR1 in mammalian embryonic kidney (HEK 293) cells, we show that this enzyme is bifunctional, being able to generate both ferrous iron and H2O2. It was previously described that protozoans knockout for LFR1 have their differentiation to virulent forms (amastigote and metacyclic promastigote) impaired. In this work, we observed that LFR1 overexpression stimulates protozoan differentiation to amastigote forms, reinforcing the importance of this enzyme in L. amazonensis life cycle regulation. Thus, we not only identified a new source of ROS production in Leishmania, but also described, for the first time, an enzyme with both ferric iron reductase and Nox activities.
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Affiliation(s)
- N Rocco-Machado
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro (UFRJ), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil; Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil
| | - D Cosentino-Gomes
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro (UFRJ), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil; Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil; Institute of Chemistry, Department of Biochemistry, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - M T Nascimento
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro (UFRJ), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil; Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil
| | - L Paes-Vieira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro (UFRJ), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil; Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil
| | - Y A Khan
- Department of Cell Biology and Molecular Genetics, University of Maryland, 20742, College Park, MD, United States
| | - B Mittra
- Department of Cell Biology and Molecular Genetics, University of Maryland, 20742, College Park, MD, United States
| | - N W Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, 20742, College Park, MD, United States
| | - J R Meyer-Fernandes
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro (UFRJ), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil; Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil.
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8
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Vilar-Pereira G, Carneiro VC, Mata-Santos H, Vicentino ARR, Ramos IP, Giarola NLL, Feijó DF, Meyer-Fernandes JR, Paula-Neto HA, Medei E, Bozza MT, Lannes-Vieira J, Paiva CN. Resveratrol Reverses Functional Chagas Heart Disease in Mice. PLoS Pathog 2016; 12:e1005947. [PMID: 27788262 PMCID: PMC5082855 DOI: 10.1371/journal.ppat.1005947] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/22/2016] [Indexed: 12/13/2022] Open
Abstract
Chronic chagasic cardiomyopathy (CCC) develops years after acute infection by Trypanosoma cruzi and does not improve after trypanocidal therapy, despite reduction of parasite burden. During disease, the heart undergoes oxidative stress, a potential causative factor for arrhythmias and contractile dysfunction. Here we tested whether antioxidants/ cardioprotective drugs could improve cardiac function in established Chagas heart disease. We chose a model that resembles B1-B2 stage of human CCC, treated mice with resveratrol and performed electrocardiography and echocardiography studies. Resveratrol reduced the prolonged PR and QTc intervals, increased heart rates and reversed sinus arrhythmia, atrial and atrioventricular conduction disorders; restored a normal left ventricular ejection fraction, improved stroke volume and cardiac output. Resveratrol activated the AMPK-pathway and reduced both ROS production and heart parasite burden, without interfering with vascularization or myocarditis intensity. Resveratrol was even capable of improving heart function of infected mice when treatment was started late after infection, while trypanocidal drug benznidazole failed. We attempted to mimic resveratrol's actions using metformin (AMPK-activator) or tempol (SOD-mimetic). Metformin and tempol mimicked the beneficial effects of resveratrol on heart function and decreased lipid peroxidation, but did not alter parasite burden. These results indicate that AMPK activation and ROS neutralization are key strategies to induce tolerance to Chagas heart disease. Despite all tissue damage observed in established Chagas heart disease, we found that a physiological dysfunction can still be reversed by treatment with resveratrol, metformin and tempol, resulting in improved heart function and representing a starting point to develop innovative therapies in CCC.
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Affiliation(s)
- Glaucia Vilar-Pereira
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Biologia das Interações, Rio de Janeiro, RJ, Brazil
| | - Vitor C. Carneiro
- Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Biologia Molecular e Tecnologia, Rio de Janeiro, RJ, Brazil
| | - Hilton Mata-Santos
- UFRJ, Instituto de Microbiologia Paulo de Góes, Departamento de Imunologial, Rio de Janeiro, RJ, Brazil
- UFRJ, Faculdade de Farmácia, Departamento de Análises Clínicas e Toxicológicas, Rio de Janeiro, RJ, Brazil
| | - Amanda R. R. Vicentino
- Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Biologia Molecular e Tecnologia, Rio de Janeiro, RJ, Brazil
| | - Isalira P. Ramos
- UFRJ, Hospital Universitário Clementino Fraga Filho, Departamento de Radiologia, Rio de Janeiro, RJ, Brazil
- UFRJ, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brazil
- UFRJ, Centro Nacional de Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Naira L. L. Giarola
- UFRJ, Instituto de Bioquímica Médica Leopoldo de Meis, Rio de Janeiro, RJ, Brazil
| | - Daniel F. Feijó
- UFRJ, Instituto de Microbiologia Paulo de Góes, Departamento de Imunologial, Rio de Janeiro, RJ, Brazil
| | - José R. Meyer-Fernandes
- UFRJ, Instituto de Bioquímica Médica Leopoldo de Meis, Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia da Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Heitor A. Paula-Neto
- UFRJ, Faculdade de Farmácia, Departamento de Fármacos, Rio de Janeiro, RJ, Brazil
| | - Emiliano Medei
- UFRJ, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brazil
- UFRJ, Centro Nacional de Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Marcelo T. Bozza
- UFRJ, Instituto de Microbiologia Paulo de Góes, Departamento de Imunologial, Rio de Janeiro, RJ, Brazil
| | - Joseli Lannes-Vieira
- Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Biologia das Interações, Rio de Janeiro, RJ, Brazil
| | - Claudia N. Paiva
- UFRJ, Instituto de Microbiologia Paulo de Góes, Departamento de Imunologial, Rio de Janeiro, RJ, Brazil
- * E-mail: ,
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9
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Oliveira SDS, Oliveira NF, Meyer-Fernandes JR, Savio LEB, Ornelas FGI, Ferreira ZS, Coutinho-Silva R, Silva CLM. Increased expression of NTPDases 2 and 3 in mesenteric endothelial cells during schistosomiasis favors leukocyte adhesion through P2Y1 receptors. Vascul Pharmacol 2016; 82:66-72. [PMID: 26924460 DOI: 10.1016/j.vph.2016.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 12/22/2015] [Accepted: 02/22/2016] [Indexed: 12/20/2022]
Abstract
Schistosomiasis is caused by an intravascular parasite and linked to phenotypic changes in endothelial cells that favor inflammation. Endothelial cells express P2Y1 receptors (P2Y1R), and their activation by ADP favors leukocyte adhesion to the endothelial monolayer. We aimed to evaluate the influence of schistosomiasis upon endothelial purinergic signaling-mediated leukocyte adhesion. Mesenteric endothelial cells and mononuclear cells from control and Schistosoma mansoni-infected mice were used in co-culture. P2Y1R levels were similar in both groups. Basal leukocyte adhesion was higher in the infected than in the control group; leukocyte adhesion increased after treatment with the P2Y1R agonist 2-MeSATP in both groups, though it only marginally increased in the infected group. Pre-incubation with the selective P2Y1R antagonist MRS2179 (0.3μM) prevented the agonist effect. However, in the infected group it also reduced the basal leukocyte adhesion, suggesting endothelial cell pre-activation. The endothelial expressions of NTPDases 2 and 3 were significantly increased in the infected group, increasing extracellular ATP hydrolysis and ADP formation by endothelial cells. Therefore, mesenteric endothelial cells are primed by schistosomiasis to a pro-inflammatory phenotype characterized by an increased expression of NTPDases 2 and 3, favoring ADP accumulation and mononuclear cell adhesion, possibly contributing to mesenteric inflammation and schistosomiasis morbidity.
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Affiliation(s)
- Suellen Darc Santos Oliveira
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Nathália F Oliveira
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - José R Meyer-Fernandes
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Luiz Eduardo Baggio Savio
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Flavia G I Ornelas
- Institute of Bioscience, University of São Paulo, 05508-090 São Paulo, SP, Brazil
| | - Zulma S Ferreira
- Institute of Bioscience, University of São Paulo, 05508-090 São Paulo, SP, Brazil
| | - Robson Coutinho-Silva
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Claudia Lucia Martins Silva
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
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10
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Alves-Bezerra M, Cosentino-Gomes D, Vieira LP, Rocco-Machado N, Gondim KC, Meyer-Fernandes JR. Identification of uncoupling protein 4 from the blood-sucking insect Rhodnius prolixus and its possible role on protection against oxidative stress. Insect Biochem Mol Biol 2014; 50:24-33. [PMID: 24746771 DOI: 10.1016/j.ibmb.2014.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/14/2014] [Accepted: 03/24/2014] [Indexed: 06/03/2023]
Abstract
Uncoupling proteins (UCPs) play a critical role in the control of the mitochondrial membrane potential (ΔΨm) due to their ability to dissipate the proton gradient, which results in the uncoupling of mitochondrial respiration from ATP production. Most reactive oxygen species generation in mitochondria occurs in complex III, due to an increase of semiquinone (Q(-)) half-life. When active, UCPs can account as a potential antioxidant system by decreasing ΔΨm and increasing mitochondrial respiration, thus reducing Q(-) life time. The hematophagous insect Rhodnius prolixus, a vector of Chagas disease, is exposed to a huge increase in oxidative stress after a blood meal because of the hydrolysis of hemoglobin and the release of the cytotoxic heme molecule. Although some protective mechanisms were already described for this insect and other hematophagous arthropods, the putative role of UCP proteins as antioxidants in this context has not been explored. In this report, two genes encoding UCP proteins (RpUcp4 and RpUcp5) were identified in the R. prolixus genome. RpUcp4 is the predominant transcript in most analyzed organs, and both mRNA and protein expression are upregulated (13- and 3-fold increase, respectively) in enterocytes the first day after the blood feeding. The increase in UCP4 expression is coincident with the decrease in hydrogen peroxide (H2O2) generation by midgut cells. Furthermore, in mitochondria isolated from enterocytes, the modulation of UCP activity by palmitic acid and GDP resulted in altered ΔΨm, as well as modulation of H2O2 generation rates. These results indicate that R. prolixus UCP4 may function in an antioxidation mechanism to protect the midgut cells against oxidative damage caused by blood digestion.
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Affiliation(s)
- Michele Alves-Bezerra
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Daniela Cosentino-Gomes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lisvane P Vieira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathália Rocco-Machado
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Katia C Gondim
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Brazil
| | - José R 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 de Biologia Estrutural e Bioimagem, Brazil.
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11
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Figliuolo VR, Chaves SP, Santoro GF, Coutinho CMLM, Meyer-Fernandes JR, Rossi-Bergmann B, Coutinho-Silva R. Periodate-oxidized ATP modulates macrophage functions during infection with Leishmania amazonensis. Cytometry A 2014; 85:588-600. [PMID: 24804957 DOI: 10.1002/cyto.a.22449] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 11/30/2013] [Accepted: 01/27/2014] [Indexed: 12/11/2022]
Abstract
Previously, we showed that treating macrophages with ATP impairs the intracellular growth of Leishmania amazonensis, and that the P2X7 purinergic receptor is overexpressed during leishmaniasis. In the present study, we directly evaluated the effect of periodate-oxidized ATP (oATP) on parasite control in Leishmania-infected macrophages. We found that oATP impaired the attachment/entrance of L. amazonensis promastigotes to C57BL/6 mouse macrophages in a P2X7 receptor-independent manner, as macrophages from P2X7(-/-) mice were similarly affected. Although oATP directly inhibited the growth of axenic promastigotes in culture, promoted rapid ultrastructural alterations, and impaired Leishmania internalization by macrophages, it did not affect intracellular parasite multiplication. Upon infection, phagosomal acidification was diminished in oATP-treated macrophages, accompanied by reduced endosomal proteolysis. Likewise, MHC class II molecules expression and ectoATPase activity was decreased by oATP added to macrophages at the time of parasite infection. These inhibitory effects were not due to a cytotoxic effect, as no additional release of lactate dehydrogenase was detected in culture supernatants. Moreover, the capacity of macrophages to produce nitric oxide and reactive oxygen species was not affected by the presence of oATP during infection. We conclude that oATP directly affects extracellular parasite integrity and macrophage functioning.
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Affiliation(s)
- V R Figliuolo
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho-IBCCF, Universidade Federal do Rio de Janeiro, RJ, Brazil; Instituto Nacional para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica, Conselho Nacional de Desenvolvimento Científico e Tecnológico/MCT, Brasil
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12
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Dick CF, Dos-Santos ALA, Meyer-Fernandes JR. Inorganic phosphate uptake in unicellular eukaryotes. Biochim Biophys Acta Gen Subj 2014; 1840:2123-7. [PMID: 24674820 DOI: 10.1016/j.bbagen.2014.03.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 02/27/2014] [Accepted: 03/17/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND Inorganic phosphate (Pi) is an essential nutrient for all organisms. The route of Pi utilization begins with Pi transport across the plasma membrane. SCOPE OF REVIEW Here, we analyzed the gene sequences and compared the biochemical profiles, including kinetic and modulator parameters, of Pi transporters in unicellular eukaryotes. The objective of this review is to evaluate the recent findings regarding Pi uptake mechanisms in microorganisms, such as the fungi Neurospora crassa and Saccharomyces cerevisiae and the parasite protozoans Trypanosoma cruzi, Trypanosoma rangeli, Leishmania infantum and Plasmodium falciparum. MAJOR CONCLUSION Pi uptake is the key step of Pi homeostasis and in the subsequent signaling event in eukaryotic microorganisms. GENERAL SIGNIFICANCE Biochemical and structural studies are important for clarifying mechanisms of Pi homeostasis, as well as Pi sensor and downstream pathways, and raise possibilities for future studies in this field.
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Affiliation(s)
- Claudia F Dick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.
| | - André L A Dos-Santos
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - José R Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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13
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Dick CF, Dos-Santos ALA, Majerowicz D, Paes LS, Giarola NL, Gondim KC, Vieyra A, Meyer-Fernandes JR. Inorganic phosphate uptake in Trypanosoma cruzi is coupled to K(+) cycling and to active Na(+) extrusion. Biochim Biophys Acta Gen Subj 2013; 1830:4265-73. [PMID: 23643965 DOI: 10.1016/j.bbagen.2013.04.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 03/30/2013] [Accepted: 04/26/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Orthophosphate (Pi) is a central compound in the metabolism of all organisms, including parasites. There are no reports regarding the mechanisms of Pi acquisition by Trypanosoma cruzi. METHODS (32)Pi influx was measured in T. cruzi epimastigotes. The expression of Pi transporter genes and the coupling of the uptake to Na(+), H(+) and K(+) fluxes were also investigated. The transport capacities of different evolutive forms were compared. RESULTS Epimastigotes grew significantly more slowly in 2mM than in 50mM Pi. Influx of Pi into parasites grown under low Pi conditions took place in the absence and presence of Na(+). We found that the parasites express TcPho84, a H(+):Pi-symporter, and TcPho89, a Na(+):Pi-symporter. Both Pi influx mechanisms showed Michaelis-Menten kinetics, with a one-order of magnitude higher affinity for the Na(+)-dependent system. Collapsing the membrane potential with carbonylcyanide-p-trifluoromethoxyphenylhydrazone strongly impaired the influx of Pi. Valinomycin (K(+) ionophore) or SCH28028 (inhibitor of (H(+)+K(+))ATPase) significantly inhibited Pi uptake, indicating that an inwardly-directed H(+) gradient energizes uphill Pi entry and that K(+) recycling plays a key role in Pi influx. Furosemide, an inhibitor of the ouabain-insensitive Na(+)-ATPase, decreased only the Na(+)-dependent Pi uptake, indicating that this Na(+) pump generates the Na(+) gradient utilized by the symporter. Trypomastigote forms take up Pi inefficiently. CONCLUSIONS Pi starvation stimulates membrane potential-sensitive Pi uptake through different pathways coupled to Na(+) or H(+)/K(+) fluxes. GENERAL SIGNIFICANCE This study unravels the mechanisms of Pi acquisition by T. cruzi, a key process in epimastigote development and differentiation to trypomastigote forms.
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Affiliation(s)
- C F Dick
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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14
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Catta-Preta CMC, Nascimento MTC, Garcia MCF, Saraiva EM, Motta MCM, Meyer-Fernandes JR. The presence of a symbiotic bacterium in Strigomonas culicis is related to differential ecto-phosphatase activity and influences the mosquito-protozoa interaction. Int J Parasitol 2013; 43:571-7. [PMID: 23562935 DOI: 10.1016/j.ijpara.2013.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 02/18/2013] [Accepted: 02/19/2013] [Indexed: 12/22/2022]
Abstract
Strigomonas culicis is a monoxenous trypanosomatid that co-evolves with a symbiotic bacterium in a mutualistic relationship that is characterized by intense metabolic exchanges between both partners. S. culicis infects and colonizes the Aedes aegypti mosquito midgut, reaches its hemocoel and then invades the salivary glands. An artificial aposymbiotic strain is unable to colonize insects, reinforcing the idea that the bacterium influences the protozoan surface composition and cell interaction. Here, we report the characterization of the hydrolytic activity of ecto-phosphatases evaluated in symbiont-bearing and aposymbiotic strains of S. culicis by incubating the protozoa with p-nitrophenyl phosphate (pNPP) at different pH levels, in the presence of phosphatase inhibitors, and with several divalent metals. The symbiont-bearing and aposymbiotic cells differ in their ecto-phosphatase enzymes, based on their activities and specificities. Furthermore, the ability of the protozoan to bind to the mosquito midgut and salivary glands was impaired by ecto-phosphatase inhibition. Taken together, our data suggest that the symbiont influences the host protozoan ecto-phosphatase activity and indicate a possible role of this enzyme during mosquito tissue colonization by S. culicis.
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Affiliation(s)
- C M C Catta-Preta
- Instituto de Biofísica Carlos Chagas Filho, 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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15
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Majerowicz D, Cezimbra MP, Alves-Bezerra M, Entringer PF, Atella GC, Sola-Penna M, Meyer-Fernandes JR, Gondim KC. Rhodnius prolixus lipophorin: lipid composition and effect of high temperature on physiological role. Arch Insect Biochem Physiol 2013; 82:129-140. [PMID: 23361613 DOI: 10.1002/arch.21080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Lipophorin is a major lipoprotein that transports lipids in insects. In Rhodnius prolixus, it transports lipids from midgut and fat body to the oocytes. Analysis by thin-layer chromatography and densitometry identified the major lipid classes present in the lipoprotein as diacylglycerol, hydrocarbons, cholesterol, and phospholipids (PLs), mainly phosphatidylethanolamine and phosphatidylcholine. The effect of preincubation at elevated temperatures on lipophorin capacity to deliver or receive lipids was studied. Transfer of PLs to the ovaries was only inhibited after preincubation of lipophorin at temperatures higher than 55 °C. When it was pretreated at 75 °C, maximal inhibition of phospholipid transfer was observed after 3-min heating and no difference was observed after longer times, up to 60 min. The same activity was also obtained when lipophorin was heated for 20 min at 75 °C at protein concentrations from 0.2 to 10 mg/ml. After preincubation at 55 °C, the same rate of lipophorin loading with PLs at the fat body was still present, and 30% of the activity was observed at 75 °C. The effect of temperature on lipophorin was also analyzed by turbidity and intrinsic fluorescence determinations. Turbidity of a lipophorin solution started to increase after preincubations at temperatures higher than 65 °C. Emission fluorescence spectra were obtained for lipophorin, and the spectral area decreased after preincubations at 85 °C or above. These data indicated no difference in the spectral center of mass at any tested temperature. Altogether, these results demonstrate that lipophorin from R. prolixus is very resistant to high temperatures.
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Affiliation(s)
- David Majerowicz
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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16
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Russo-Abrahão T, Alves-Bezerra M, Majerowicz D, Freitas-Mesquita AL, Dick CF, Gondim KC, Meyer-Fernandes JR. Transport of inorganic phosphate in Leishmania infantum and compensatory regulation at low inorganic phosphate concentration. Biochim Biophys Acta 2013; 1830:2683-2689. [PMID: 23671929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
BACKGROUND Proliferation of Leishmania infantum depends on exogenous inorganic phosphate (P(i)) but little is known about energy metabolism and transport of P(i) across the plasma membrane in Leishmania sp. METHODS We investigated the kinetics of 32P(i) transport, the influence of H+ and K+ ionophores and inhibitors, and expression of the genes for the Na+:P(i) and H+:P(i) cotransporters. RESULTS The proton ionophore FCCP, bafilomycin A1 (vacuolar ATPase inhibitor), nigericin (K+ ionophore) and SCH28080 (an inhibitor of H+, K(+)-ATPase) all inhibited the transport of P(i). This transport showed Michaelis-Menten kinetics with K0.5 and V(max) values of 0.016 +/- 0.002 mM and 564.9 +/- 18.06 pmol x h(-1) x 10(-7) cells, respectively. These values classify the P(i) transporter of L. infantum among the high-affinity transporters, a group that includes Pho84 of Saccharomyces cerevisiae. Two sequences were identified in the L. infantum genome that code for phosphate transporters. However, transcription of the PHO84 transporter was 10-fold higher than the PHO89 transporter in this parasite. Accordingly, P(i) transport and LiPho84 gene expression were modulated by environmental P(i) variations. CONCLUSIONS These findings confirm the presence of a P(i) transporter in L. infantum, similar to PHO84 in S. cerevisiae, that contributes to the acquisition of inorganic phosphate and could be involved in growth and survival of the promastigote forms of L. infantum. GENERAL SIGNIFICANCE This work provides the first description of a PHO84-like P(i) transporter in a Trypanosomatide parasite of the genus Leishmania, responsible for many infections worldwide.
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Affiliation(s)
- T Russo-Abrahão
- Instituto de Microbiologia Professor Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Fernandes AC, Soares DC, Saraiva EM, Meyer-Fernandes JR, Souto-Padrón T. Different secreted phosphatase activities inLeishmania amazonensis. FEMS Microbiol Lett 2013; 340:117-28. [DOI: 10.1111/1574-6968.12080] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/03/2013] [Accepted: 01/07/2013] [Indexed: 12/21/2022] Open
Affiliation(s)
- Anne C.S. Fernandes
- Instituto de Microbiologia Paulo de Góes; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Rio de Janeiro; Brasil
| | - Deivid C. Soares
- Instituto de Microbiologia Paulo de Góes; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Rio de Janeiro; Brasil
| | - Elvira M. Saraiva
- Instituto de Microbiologia Paulo de Góes; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Rio de Janeiro; Brasil
| | - José R. Meyer-Fernandes
- Instituto de Bioquímica Médica; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Rio de Janeiro; Brasil
| | - Thaïs Souto-Padrón
- Instituto de Microbiologia Paulo de Góes; Centro de Ciências da Saúde; Universidade Federal do Rio de Janeiro; Rio de Janeiro; Brasil
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18
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Santos R, Alves-Bezerra M, Rosas-Oliveira R, Majerowicz D, Meyer-Fernandes JR, Gondim KC. Gene identification and enzymatic properties of a membrane-bound trehalase from the ovary of Rhodnius prolixus. Arch Insect Biochem Physiol 2012; 81:199-213. [PMID: 22851503 DOI: 10.1002/arch.21043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Trehalose represents the main hemolymph sugar in most insects and its metabolic availability is regulated by trehalase. In this study, trehalase activity associated with the reproductive system was investigated in the insect Rhodnius prolixus, a hematophagous hemipteran vector of Chagas' disease. A single-copy gene that encodes a membrane-bound trehalase (RpTre-2) was identified in the genome of R. prolixus. RpTre-2 deduced amino acid sequence is closely related to other insect membrane-bound trehalases. The expression of this gene was detected in all analyzed organs, including ovary, where total trehalase enzymatic activity was determined, and was highest at day 7 after blood meal. Ovary membranes showed a major trehalase specific activity, which confirmed the presence of a membrane-bound trehalase in this insect. This trehalase activity seemed not to be regulated at transcriptional level, as the expression of RpTre-2 gene in the ovary did not change over the days after feeding. Similarly, ovarian follicles at different developmental stages did not show any variation in the transcription level of this gene. The RpTre-2 kinetic parameters were also investigated. Activity was highest at pH 5.5 and followed Michaelis-Menten kinetics, with an apparent K(m) = 1.42 ± 0.36 mM and Vmax = 167.90 ± 12.91 nmol/mg protein/h. These data reveal the presence of a membrane-bound trehalase in R. prolixus that is active in ovary and probably takes part in the insect carbohydrate metabolism associated with the reproductive process.
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Affiliation(s)
- Rachel Santos
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Russo-Abrahão T, Alves-Bezerra M, Majerowicz D, Freitas-Mesquita AL, Dick CF, Gondim KC, Meyer-Fernandes JR. Transport of inorganic phosphate in Leishmania infantum and compensatory regulation at low inorganic phosphate concentration. Biochim Biophys Acta Gen Subj 2012. [PMID: 23201200 DOI: 10.1016/j.bbagen.2012.11.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Proliferation of Leishmania infantum depends on exogenous inorganic phosphate (Pi) but little is known about energy metabolism and transport of Pi across the plasma membrane in Leishmania sp. METHODS We investigated the kinetics of 32Pi transport, the influence of H+ and K+ ionophores and inhibitors, and expression of the genes for the Na+:Pi and H+:Pi cotransporters. RESULTS The proton ionophore FCCP, bafilomycin A1 (vacuolar ATPase inhibitor), nigericin (K+ ionophore) and SCH28080 (an inhibitor of H+, K+-ATPase) all inhibited the transport of Pi. This transport showed Michaelis-Menten kinetics with K0.5 and Vmax values of 0.016±0.002mM and 564.9±18.06pmol×h-1×10-7cells, respectively. These values classify the Pi transporter of L. infantum among the high-affinity transporters, a group that includes Pho84 of Saccharomyces cerevisiae. Two sequences were identified in the L. infantum genome that code for phosphate transporters. However, transcription of the PHO84 transporter was 10-fold higher than the PHO89 transporter in this parasite. Accordingly, Pi transport and LiPho84 gene expression were modulated by environmental Pi variations. CONCLUSIONS These findings confirm the presence of a Pi transporter in L. infantum, similar to PHO84 in S. cerevisiae, that contributes to the acquisition of inorganic phosphate and could be involved in growth and survival of the promastigote forms of L. infantum. GENERAL SIGNIFICANCE This work provides the first description of a PHO84-like Pi transporter in a Trypanosomatide parasite of the genus Leishmania, responsible for many infections worldwide.
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Affiliation(s)
- T Russo-Abrahão
- Instituto de Microbiologia Professor Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - M Alves-Bezerra
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - D Majerowicz
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - A L Freitas-Mesquita
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - C F Dick
- Instituto de Microbiologia Professor Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - K C Gondim
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - J R Meyer-Fernandes
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Medica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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20
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Ribeiro MC, Costa-Alves MS, Wengert M, Meyer-Fernandes JR, Zancan P, Caruso-Neves C, Pinheiro AAS. Characterization of ecto-ATPase activity in the surface of LLC-PK1 cells and its modulation by ischemic conditions. Biochim Biophys Acta Gen Subj 2012; 1820:2030-6. [PMID: 23000490 DOI: 10.1016/j.bbagen.2012.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 09/04/2012] [Accepted: 09/14/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND The concentration of extracellular nucleotides is regulated by enzymes that have their catalytic site facing the extracellular space, the so-called ecto-enzymes. METHODS We used LLC-PK1 cells, a well-characterized porcine renal proximal tubule cell line, to biochemically characterize ecto-ATPase activity in the luminal surface. The [γ-(32)P]Pi released after reaction was measured in aliquots of the supernatant by liquid scintillation. RESULTS This activity was linear with time up to 20min of reaction and stimulated by divalent metals. The ecto-ATPase activity measured in the presence of 5mM MgCl(2) was (1) optimum at pH 8, (2) insensitive to different inhibitors of intracellular ATPases, (3) inhibited by 1mM suramin, an inhibitor of ecto-ATPases, (4) sensitive to high concentrations of sodium azide (NaN(3)) and (5) also able to hydrolyze ADP in the extracellular medium. The ATP:ADP hydrolysis ratio calculated was 4:1. The ecto-ADPase activity was also inhibited by suramin and NaN(3). The dose-response of ATP revealed a hyperbolic profile with maximal velocity of 25.2±1.2nmol Pixmg(-1)xmin(-1) and K(0.5) of 0.07±0.01mM. When cells were submitted to ischemia, the E-NTPDase activity was reduced with time, achieving 71% inhibition at 60min of ischemia. CONCLUSION Our results suggest that the ecto-ATPase activity of LLC-PK1 cells has the characteristics of a type 3 E-NTPDase which is inhibited by ischemia. GENERAL SIGNIFICANCE This could represent an important pathophysiologic mechanism that explains the increase in ATP concentration in the extracellular milieu in the proximal tubule during ischemia.
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Affiliation(s)
- M C Ribeiro
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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21
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Kneipp LF, Magalhães AS, Abi-Chacra ÉA, Souza LOP, Alviano CS, Santos ALS, Meyer-Fernandes JR. Surface phosphatase inRhinocladiella aquaspersa: biochemical properties and its involvement with adhesion. Med Mycol 2012; 50:570-8. [DOI: 10.3109/13693786.2011.653835] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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22
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Dos-Santos AL, Dick CF, Alves-Bezerra M, Silveira TS, Paes LS, Gondim KC, Meyer-Fernandes JR. Interaction between Trypanosoma rangeli and the Rhodnius prolixus salivary gland depends on the phosphotyrosine ecto-phosphatase activity of the parasite. Int J Parasitol 2012; 42:819-27. [DOI: 10.1016/j.ijpara.2012.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/30/2012] [Accepted: 05/31/2012] [Indexed: 12/21/2022]
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23
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Figueiredo AB, Serafim TD, Marques-da-Silva EA, Meyer-Fernandes JR, Afonso LCC. Leishmania amazonensis impairs DC function by inhibiting CD40 expression via A2B adenosine receptor activation. Eur J Immunol 2012; 42:1203-15. [PMID: 22311598 DOI: 10.1002/eji.201141926] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dendritic cells (DCs) play an essential role in the modulation of immune responses and several studies have evaluated the interactions between Leishmania parasites and DCs. While extracellular ATP exhibits proinflammatory properties, adenosine is an important anti-inflammatory mediator. Here we investigated the effects of Leishmania infection on DC responses and the participation of purinergic signalling in this process. Bone marrow-derived dendritic cells (BMDCs) from C57BL/6J mice infected with Leishmania amazonensis, Leishmania braziliensis or Leishmania major metacyclic promastigotes showed decreased major histocompatibility complex (MHC) class II and CD86 expression and increased ectonucleotidase expression as compared with uninfected cells. In addition, L. amazonensis-infected DCs, which had lower CD40 expression, exhibited a decreased ability to induce T-cell proliferation. The presence of MRS1754, a highly selective A(2B) adenosine receptor antagonist at the time of infection increased MHC class II, CD86 and CD40 expression in L. amazonensis-infected DCs and restored the ability of the infected DCs to induce T-cell proliferation. Similar results were obtained through the inhibition of extracellular ATP hydrolysis using suramin. In conclusion, we propose that A(2B) receptor activation may be used by L. amazonensis to inhibit DC function and evade the immune response.
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Affiliation(s)
- Amanda B Figueiredo
- Laboratório de Imunoparasitologia, Departamento de Ciências Biológicas, ICEB/NUPEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
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24
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Majerowicz D, Alves-Bezerra M, Logullo R, Fonseca-de-Souza AL, Meyer-Fernandes JR, Braz GRC, Gondim KC. Looking for reference genes for real-time quantitative PCR experiments in Rhodnius prolixus (Hemiptera: Reduviidae). Insect Mol Biol 2011; 20:713-722. [PMID: 21929722 DOI: 10.1111/j.1365-2583.2011.01101.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Quantitative real-time PCR (qPCR) has become one of the most used techniques to measure gene expression. However, normalization of gene expression data against reference genes is essential, although these are usually used without any kind of validation. The expression of seven genes was compared in organs of Rhodnius prolixus under diverse conditions, using published software to test gene expression stability. Rp18S and elongation factor 1 (RpEF -1) were the most reliable genes for normalization in qPCR when gene expression in different organs was compared. Moreover, both genes were found to be the best references when transcript levels were compared in the posterior midgut of insects infected with Trypanosoma cruzi. Rp18S was also the best reference gene in the fat bodies of unfed and fed insects. By contrast, RpEF-1 was found to be the best reference gene for comparison between posterior midguts, and RpMIP or RpActin should be used to compare gene expression in the ovaries. Although Rp18S is indicated here as the best reference in most cases, reports from the literature show that it is difficult to find an optimum reference gene. Nevertheless, validation of candidate genes to be taken as references is important when new experimental conditions are tested to avoid incorrect data interpretation.
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Affiliation(s)
- D Majerowicz
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Ilha do Fundão, Rio de Janeiro, RJ, Brazil.
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25
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Souza VLD, Veras PST, Welby-Borges M, Silva TMC, Leite BR, Ferraro RB, Meyer-Fernandes JR, Barral A, Costa JML, de Freitas LAR. Immune and inflammatory responses to Leishmania amazonensis isolated from different clinical forms of human leishmaniasis in CBA mice. Mem Inst Oswaldo Cruz 2011; 106:23-31. [PMID: 21340351 DOI: 10.1590/s0074-02762011000100004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 11/04/2010] [Indexed: 11/22/2022] Open
Abstract
Leishmania amazonensis causes different diseases depending on the host and parasitic virulence factors. In this study, CBA mice were infected with L. amazonensis isolates from patients with localized (Ba125), diffuse cutaneous (Ba276) or visceral leishmaniasis (Ba109). Mice infected with Ba125 and Ba276 progressed rapidly and lesions displayed an infiltrate rich in parasitized macrophages and were necrotic and ulcerated. Ba109 induced smaller lesions and a mixed inflammatory infiltrate without necrosis or ulceration. Ba109 induced an insidious disease with lower parasite load in CBA mice, similar to human disease. Levels of IFN-γ, IL-4 and IL-10 did not differ among the groups. Because all groups were unable to control the infection, expression of IL-4 associated with low production of IFN-γ in the early phase of infection may account for susceptibility, but others factors may contribute to the differences observed in inflammatory responses and infection progression. Evaluation of some parasitic virulence factors revealed that Ba276 exhibits higher ecto-ADPase and 5'-nucleotidase activities compared to the Ba109 and Ba125 strains. Both Ba276 and Ba125 had higher arginase activity in comparison to Ba109. Finally, these data suggest that the differences in enzyme activities among parasites can account for differences in host inflammatory responses and infection progression.
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Affiliation(s)
- Valderes L de Souza
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, BA, Brasil
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26
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Portela MB, Kneipp LF, Ribeiro de Souza IP, Holandino C, Alviano CS, Meyer-Fernandes JR, De Araújo Soares RM. Ectophosphatase activity in Candida albicans influences fungal adhesion: study between HIV-positive and HIV-negative isolates. Oral Dis 2010; 16:431-7. [DOI: 10.1111/j.1601-0825.2009.01644.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mariano AC, Santos R, Gonzalez MS, Feder D, Machado EA, Pascarelli B, Gondim KC, Meyer-Fernandes JR. Synthesis and mobilization of glycogen and trehalose in adult male Rhodnius prolixus. Arch Insect Biochem Physiol 2009; 72:1-15. [PMID: 19514081 DOI: 10.1002/arch.20319] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The vector of Chagas' disease, Rhodnius prolixus, feeds exclusively on blood. The blood meals are slowly digested, and these insects wait some weeks before the next meal. During the life of an insect, energy-requiring processes such as moulting, adult gonadal and reproductive growth, vitellogenesis, muscular activity, and fasting, lead to increased metabolism. Carbohydrates are a major source of energy and their mobilization is important. We determined the amounts of glycogen, trehalose, and glucose present in the fat body and/or hemolymph of adult males of R. prolixus and recorded the processes of accumulation and mobilization of these carbohydrates. We also tested our hypothesis that these processes are under endocrine control. The amount of glycogen in the fat body progressively increased until the fourth day after feeding (from 9.3+/-2.2 to 77. 3+/-7.5 microg/fat body), then declined to values around 36.3+/-4.9 microg/fat body on the fifteenth day after the blood meal. Glycogen synthesis was eliminated in decapitated insects and head-transplanted insects synthesized glycogen. The amount of trehalose in the fat body increased until the sixth day after feeding (from 16. 6+/-1.7 to 40. 6+/-5.3 nmol/fat body), decreased abruptly, and stabilized between days 7 and 15 at values ranging around 15-19 nmol/fat body. Decapitated insects did not synthesize trehalose after feeding, and this effect was reversed in head-transplanted insects. The concentration of trehalose in the hemolymph increased after the blood meal until the third day (from 0.07+/-0.01 to 0.75+/-0.05 mM) and at the fourth day it decreased until the ninth day (0.21+/-0.01 mM), when it increased again until the fourteenth day (0.79+/-0.06 mM) after the blood meal, and then declined again. In decapitated insects, trehalose concentrations did not increase soon after the blood meal and at the third day it was very low, but on the fourteenth day it was close to the control values. The concentration of glucose in the hemolymph of untreated insects remained low and constant (0.18+/-0.01 mM) during the 15 days after feeding, but in decapitated insects it progressively increased until the fifteenth day (2.00+/-0.10 mM). We recorded the highest trehalase activity in midgut, which was maximal at the eighth day after feeding (2,830+/-320 nmol of glucose/organ/h). We infer that in Rhodnius prolixus, the metabolism of glycogen, glucose, and trehalose are controlled by factors from the brain, according to physiological demands at different days after the blood meal.
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Affiliation(s)
- Ana C Mariano
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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28
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Amazonas JN, Cosentino-Gomes D, Werneck-Lacerda A, de Sá Pinheiro AA, Lanfredi-Rangel A, Souza WD, Meyer-Fernandes JR. Giardia lamblia: Characterization of ecto-phosphatase activities. Exp Parasitol 2009; 121:15-21. [DOI: 10.1016/j.exppara.2008.09.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 09/16/2008] [Accepted: 09/18/2008] [Indexed: 11/29/2022]
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Santos R, Mariano AC, Rosas-Oliveira R, Pascarelli B, Machado EA, Meyer-Fernandes JR, Gondim KC. Carbohydrate accumulation and utilization by oocytes of Rhodnius prolixus. Arch Insect Biochem Physiol 2008; 67:55-62. [PMID: 18064701 DOI: 10.1002/arch.20217] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The processes of accumulation and mobilization of carbohydrate stores in eggs of Rhodnius prolixus were analyzed. During oogenesis, the total amounts of glycogen, glucose, and trehalose increased with an accumulation of proteins, especially when oocytes grew from 1.0 to 1.5 mm in length. At 2.0 mm length, when oocytes were ready for oviposition, nutrient reserves did not increase appreciably and trehalose content decreased. Mating did not affect the final content of carbohydrates or proteins in oocytes of mated and virgin females. A trehalase activity was detected in follicles containing vitellogenic oocytes, 1.0 and 1.5 mm length, in both mated and virgin females. This activity was extremely low in chorionated, 2.0-mm oocytes. After oviposition, glycogen content decreased in fertilized eggs, but not in unfertilized ones, and some was present in newly hatched nymphs. Glucose content remained constant in unfertilized eggs, but increased in fertilized ones, while total protein amount was constant in both groups after egg laying.
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Affiliation(s)
- Rachel Santos
- Instituto de Bioquímica Médica, Universidade Federal do Rio Janeiro, Rio de Janeiro, Brazil
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30
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Kiffer-Moreira T, Pinheiro AAS, Pinto MR, Esteves FF, Souto-Padrón T, Barreto-Bergter E, Meyer-Fernandes JR. Mycelial forms of Pseudallescheria boydii present ectophosphatase activities. Arch Microbiol 2007; 188:159-66. [PMID: 17429613 DOI: 10.1007/s00203-007-0232-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Revised: 02/28/2007] [Accepted: 03/05/2007] [Indexed: 10/23/2022]
Abstract
Phosphatase activities were characterized in intact mycelial forms of Pseudallescheria boydii, which are able to hydrolyze the artificial substrate p-nitrophenylphosphate (p-NPP) to p-nitrophenol (p-NP) at a rate of 41.41+/-2.33 nmol p-NP per h per mg dry weight, linearly with increasing time and with increasing cell density. MgCl2, MnCl2 and ZnCl2 were able to increase the (p-NPP) hydrolysis while CdCl2 and CuCl2 inhibited it. The (p-NPP) hydrolysis was enhanced by increasing pH values (2.5-8.5) over an approximately 5-fold range. High sensitivity to specific inhibitors of alkaline and acid phosphatases suggests the presence of both acid and alkaline phosphatase activities on P. boydii mycelia surface. Cytochemical localization of the acid and alkaline phosphatase showed electron-dense cerium phosphate deposits on the cell wall, as visualized by electron microscopy. The product of p-NPP hydrolysis, inorganic phosphate (Pi), and different inhibitors for phosphatase activities inhibited p-NPP hydrolysis in a dose-dependent manner, but only the inhibition promoted by sodium orthovanadate and ammonium molybdate is irreversible. Intact mycelial forms of P. boydii are also able to hydrolyze phosphoaminoacids with different specificity.
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Affiliation(s)
- Tina Kiffer-Moreira
- Instututo de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, bloco H, Cidade Universitária, Rio de Janeiro, RJ, 21941-590, Brazil
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31
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Dutra PML, Couto LC, Lopes AHCS, Meyer-Fernandes JR. Characterization of ecto-phosphatase activities of Trypanosoma cruzi: a comparative study between Colombiana and Y strains. Acta Trop 2006; 100:88-95. [PMID: 17055992 DOI: 10.1016/j.actatropica.2006.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2005] [Revised: 04/18/2006] [Accepted: 05/19/2006] [Indexed: 12/22/2022]
Abstract
The etiological agent of Chagas disease, Trypanosoma cruzi, is consisted of two phylogenetic lineages. Using live epimastigotes, in this study we have characterized ecto-phosphatase activities of two strains of T. cruzi, one (Y strain) is a member of group T. cruzi I and the other (Colombiana) is a member of group T. cruzi II. About one-third of the total ecto-phosphatase activity from the Y strain was Mg(2+)-dependent, but no such activity was observed with Colombiana. The level of Mg(2+)-independent activity was dramatically different in the two strains, with Colombiana showing more than 15-fold higher activity. Experiments using classical inhibitors of acid phosphatases, as well as inhibitors of phosphotyrosine phosphatase, showed a decrease in these phosphatase activities, with different patterns of inhibition. The Mg(2+)-independent activities of the Colombiana and Y strains decreased inversely with pH, varying from 6.5 to 8.0. On the other hand, the Mg(2+)-dependent activity of the Y strain increased concomitantly with the increase in pH in the same range.
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Affiliation(s)
- P M L Dutra
- Disciplina de Parasitologia, DPL, FCM, UERJ, Rua Prof. Manoel de Abreu 444, Vila Isabel, Rio de Janeiro, RJ 20550-170, Brazil
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32
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Pinheiro CM, Martins-Duarte ES, Ferraro RB, Fonseca de Souza AL, Gomes MT, Lopes AHCS, Vannier-Santos MA, Santos ALS, Meyer-Fernandes JR. Leishmania amazonensis: Biological and biochemical characterization of ecto-nucleoside triphosphate diphosphohydrolase activities. Exp Parasitol 2006; 114:16-25. [PMID: 16603157 DOI: 10.1016/j.exppara.2006.02.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 02/02/2006] [Accepted: 02/06/2006] [Indexed: 10/24/2022]
Abstract
The presence of Leishmania amazonensis ecto-nucleoside triphosphate triphosphohydrolase activities was demonstrated using antibodies against different NTPDase members by Western blotting, flow cytometry, and immunoelectron microscopy analysis. Living promastigote cells sequentially hydrolyzed the ATP molecule generating ADP, AMP, and adenosine, indicating that this surface enzyme may play a role in the salvage of purines from the extracellular medium. The L. amazonensis ecto-NTPDase activities were insensitive to Triton X-100, but they were enhanced by divalent cations, such as Mg(2+). In addition, the ecto-NTPDase activities decreased with time for 96 h when promastigotes were grown in vitro. On the other hand, these activities increased considerably when measured in living amastigote forms. Furthermore, the treatment with adenosine, a mediator of several relevant biological phenomena, induced a decrease in the reactivity with anti-CD39 antibody, raised against mammalian E-NTPDase, probably because of down regulation in the L. amazonensis ecto-NTPDase expression. Also, adenosine and anti-NTPDase antibodies induced a significant diminishing in the interaction between promastigotes of L. amazonensis and mouse peritoneal macrophages.
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Affiliation(s)
- Carla M Pinheiro
- Instituto de Bioquímica Médica (IBqM), Universidade Federal do Rio de Janeiro (UFRJ), Centro de Ciências da Saúde (CCS), Bloco H, Cidade Universitária, Ilha do Fundão, 21541-590 Rio de Janeiro, Brazil
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33
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Gomes SAO, Fonseca de Souza AL, Silva BA, Kiffer-Moreira T, Santos-Mallet JR, Santos ALS, Meyer-Fernandes JR. Trypanosoma rangeli: Differential expression of cell surface polypeptides and ecto-phosphatase activity in short and long epimastigote forms. Exp Parasitol 2006; 112:253-62. [PMID: 16442100 DOI: 10.1016/j.exppara.2005.11.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 11/18/2005] [Accepted: 11/21/2005] [Indexed: 11/30/2022]
Abstract
Trypanosoma rangeli is a parasite of a numerous wild and domestic animals, presenting wide geographical distribution and high immunological cross-reactivity with Trypanosoma cruzi, which may lead to misdiagnosis. T. rangeli has a complex life cycle, involving distinct morphological and functional forms in the vector. Here, we characterized the cell surface polypeptides and the phosphatase activities in short and long epimastigotes forms of T. rangeli, using intact living parasites. The surface protein profile revealed by the incubation of parasites with biotin showed a preferential expression of the 97, 70, 50, 45, 25-22, and 15 kDa biotinylated polypeptides in the long forms, in contrast to the 55 and 28 kDa biotinylated polypeptides synthesized by the short epimastigotes. Additionally, flow cytometry analysis showed that the short forms had relatively lower biotin surface binding than long ones. The involvement of phosphatases with the trypanosomatid differentiation has been proposed. In this sense, T. rangeli living parasites were able to hydrolyze the artificial substrate p-nitrophenylphosphate at a rate of 25.57+/-2.03 and 10.09+/-0.93 nmol p-NPP x h(-1) x 10(7) cells for the short and long epimastigotes, respectively. These phosphatase activities were linear with time for at least 60 min and the optimum pH lies in the acid range. Classical inhibitors of acid phosphatases, such as ammonium molybdate, sodium fluoride, and zinc chloride, showed a significant decrease in these phosphatase activities, with different patterns of inhibition. Additionally, these phosphatase activities presented different kinetic parameters (Km and Vmax) and distinct sensitivities to divalent cations. Both epimastigotes were unable to release phosphatase to the extracellular environment. Cytochemical analysis demonstrated the localization of these enzymes on the parasite surfaces (cell body and flagellum) and in intracellular vacuoles, resembling acidocalcisomes.
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Affiliation(s)
- Suzete A O Gomes
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica (IBqM), Bloco H, Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Av. Brigadeiro Trompowsky s/n, Ilha do Fundão, Rio de Janeiro, RJ 21941-590, Brazil
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Entringer PF, Gondim KC, Meyer-Fernandes JR. Ecto-nucleotidase activities in the fat body of Rhodnius prolixus. Arch Insect Biochem Physiol 2006; 61:1-9. [PMID: 16380977 DOI: 10.1002/arch.20087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In this study, we describe the ability of intact fat body of an insect, Rhodnius prolixus, to hydrolyze extracellular ATP. In these fat bodies, the ATP hydrolysis was low in the absence of any divalent metal, and was stimulated by MgCl(2). Both activities (in the absence or presence of MgCl(2)) were linear with time for at least 30 min. In order to confirm the observed nucleotidase activities as ecto-nucleotidases, we used an impermeant inhibitor, DIDS (4, 4'-diisothiocyanostylbene 2'-2'-disulfonic acid). This reagent inhibited both nucleotidase activities and its inhibitory effect was suppressed by ATP. Both ecto-nucleotidase activities were insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin, ouabain, vanadate, molybdate, sodium fluoride, levamizole, tartrate, p-NPP, sodium phosphate, and suramin. Concanavalin A, activator of some ecto-ATPases, was able to stimulate the Mg(2+)-independent nucleotidase activity, but not the Mg(2+)-dependent one. The Mg(2+)-independent nucleotidase activity was enhanced with increases in the pH in the range between 6.4-8.0, but the Mg(2+)-dependent nucleotidase activity was not affected. Besides MgCl(2) , the ecto-ATPase activity was also stimulated by CaCl(2),() MnCl(2), and SrCl(2), but not by ZnCl(2). ATP, ADP, and AMP were the best substrates for the Mg(2+)-dependent ecto-nucleotidase activity, and CTP, GTP, and UTP produced very low reaction rates. However, the Mg(2+)-independent nucleotidase activity recognized all these nucleotides producing similar reaction rates, but GTP was a less efficient substrate. The possible role of the two ecto-nucleotidase activities present on the cell surface of fat body of Rhodnius prolixus, which are distinguished by their substrate specificity and their response to Mg(2+), is discussed.
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Affiliation(s)
- Petter F Entringer
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, sala H2-013, Ilha do Fundão, 21941-590 Rio de Janeiro, Brazil
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35
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Kneipp LF, Rodrigues ML, Holandino C, Esteves FF, Souto-Padrón T, Alviano CS, Travassos LR, Meyer-Fernandes JR. Ectophosphatase activity in conidial forms of Fonsecaea pedrosoi is modulated by exogenous phosphate and influences fungal adhesion to mammalian cells. Microbiology (Reading) 2005; 150:3355-62. [PMID: 15470114 DOI: 10.1099/mic.0.27405-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A cell-wall-associated phosphatase in hyphae of Fonsecaea pedrosoi, a fungal pathogen causing chromoblastomycosis, was previously characterized by the authors. In the present work, the expression of an acidic ectophosphatase activity in F. pedrosoi conidial forms was investigated. The surface phosphatase activity in F. pedrosoi is associated with the cell wall, as demonstrated by transmission electron microscopy. This enzyme activity was strongly inhibited by exogenous inorganic phosphate (P(i)). Accordingly, removal of P(i) from the culture medium of F. pedrosoi resulted in a marked (130-fold) increase of ectophosphatase activity. With the artificial phosphatase substrate p-nitrophenyl phosphate, a Km value of 0.63+/-0.04 mM was estimated for the phosphatase activity of fungal cells strongly expressing the enzyme activity. This enzyme activity was not modulated by cations. Conidia with greater ectophosphatase activity showed greater adherence to mammalian cells than did fungi cultivated in the presence of P(i) (low phosphatase activity). Surface phosphatase activity was apparently involved in the adhesion to host cells, since the enhanced attachment of F. pedrosoi to host cells was reversed by pre-treatment of conidia with phosphatase inhibitor. Since conidial forms are the putative infectious propagules in chromoblastomycosis, the expression and activity of acidic surface phosphatases in these cells may contribute to the early mechanisms required for disease establishment.
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Affiliation(s)
- Lucimar F Kneipp
- Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil
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36
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de Melo LDB, Nepomuceno-Silva JL, Sant'Anna C, Eisele N, Ferraro RB, Meyer-Fernandes JR, de Souza W, Cunha-e-Silva NL, Lopes UG. TcRho1 of Trypanosoma cruzi: role in metacyclogenesis and cellular localization. Biochem Biophys Res Commun 2004; 323:1009-16. [PMID: 15381100 DOI: 10.1016/j.bbrc.2004.08.197] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Indexed: 11/23/2022]
Abstract
Here we have investigated the function of TcRho1, a Rho family orthologue from the parasite Trypanosoma cruzi. We have selected parasites overexpressing wild-type TcRho1 and a truncated form of TcRho1 (TcRho1-DeltaCaaX) which is unable to undergo farnesylation and supposed to interfere with recruitment of Rho effectors to membranes. TcRho1 protein was localized at the anterior region of wild-type and TcRho1 overexpressing epimastigotes, suggesting association with the Golgi apparatus. Accordingly, parasites overexpressing TcRho1-DeltaCaaX presented cytoplasmic fluorescence. To address the function of TcRho1 during differentiation, from epimastigotes to trypomastigotes, we submitted parasites overexpressing the above-cited lineages to metacyclogenesis assays. Parasites overexpressing TcRho1-DeltaCaaX generated a discrete number of metacyclic trypomastigotes when compared with other lineages. Strikingly, TcRho1-DeltaCaaX cells died synchronously during the process of metacyclogenesis.
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Affiliation(s)
- Luiz Dione B de Melo
- Laboratório de Parasitologia Molecular, Instituto de Biofísica Carlos Chagas Filho, CCS, UFRJ, Rio de Janeiro, Brazil
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Ferraro RB, Sousa JL, Cunha RDC, Meyer-Fernandes JR. Characterization of an ecto-phosphatase activity in malpighian tubules of hematophagous bug Rhodnius prolixus. Arch Insect Biochem Physiol 2004; 57:40-49. [PMID: 15352154 DOI: 10.1002/arch.20013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have characterized a phosphatase activity present on the external surface of intact Malpighian tubules in Rhodnius prolixus. This phosphatase hydrolyses the substrate p-nitrophenyl phosphate at a rate of 3.38 +/- 0.07 nmol Pi x mg(-1) x min(-1). Phosphatase activity decreased with the increase of the pH from 6.4 to 7.6 pH, a range in which tubules cellular integrity was maintained for at least 1 h. Classical inhibitors of acid phosphatase, such as ammonium molybdate, fluoride, vanadate, mpV-PIC, and bpV-PHEN, caused different patters of inhibition. The ecto-phosphatase present an apparent Km of 1.67 +/- 0.34 mM and Vmax of 5.71 +/- 0.37 nmol Pi x mg(-1) x min(-1) for p-NPP. Zinc chloride inhibited 78.2% of ecto-phosphatase activity, with Ki of 0.35 mM. Such inhibition was reversed by incubation with cysteine and GSH, but not DTT, serine, and GSSG, showing that cysteine residues are important for enzymatic activity. Phosphatase activity increased 141% three days after blood meal, and returned to basal levels 2 days later. These results suggest that ecto-phosphatase activity could be involved in a diuretic mechanism, essential in the initial days after a blood meal for the control of Rhodnius homeostasis.
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Affiliation(s)
- Rodrigo B Ferraro
- Departamento de Bioquímica Médica, ICB, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil
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38
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Jesus JB, Vannier-Santos MA, Britto C, Godefroy P, Silva-Filho FC, Pinheiro AAS, Rocha-Azevedo B, Lopes AHCS, Meyer-Fernandes JR. Trichomonas vaginalis virulence against epithelial cells and morphological variability: the comparison between a well-established strain and a fresh isolate. Parasitol Res 2004; 93:369-77. [PMID: 15205943 DOI: 10.1007/s00436-004-1134-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Accepted: 04/16/2004] [Indexed: 10/26/2022]
Abstract
The FMVI strain of Trichomonas vaginalis was freshly isolated from an asymptomatic patient, and its morphological properties and virulence in vitro compared with the well-established JT strain. The morphological variability of the parasites was assessed by differential interference microscopy and both scanning and transmission electron microscopy. The FMV1 strain presented nearly 20% amoeboid cells whereas the JT strain presented high percentages of ellipsoid but no amoeboid cells. The FMV1 morphotype population was unaltered after at least 1 year of subculturing. Electron microscopy revealed that this strain produced numerous pseudopod structures which mediated intimate contact and interdigitation among trophozoites. Dead FMV1 parasites were often phagocytosed by conspecific cells. We also compared the cytolytic capacity of these two populations against epithelial MDCK cells and its contact dependence. The FMV1 strain rapidly adhered to plastic or glass surfaces and to MDCK monolayers. This strain destroyed about 93% of the epithelial cells in 90 min whereas the cytolytic activity of the JT parasites was very much lower (about 41%). Parasite supernatants displayed no cytolytic activity, indicating contact-mediated lysis. The protozoan virulence in vitro did not correlate well with the clinical observations. The implications of these results are discussed.
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Affiliation(s)
- J B Jesus
- Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
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Kneipp LF, Palmeira VF, Pinheiro AAS, Alviano CS, Rozental S, Travassos LR, Meyer-Fernandes JR. Phosphatase activity on the cell wall of Fonsecaea pedrosoi. Med Mycol 2004; 41:469-77. [PMID: 14725320 DOI: 10.1080/10683160310001615399] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The activity of a phosphatase was characterized in intact mycelial forms of Fonsecaea pedrosoi, a pathogenic fungus that causes chromoblastomycosis. At pH 5.5, this fungus hydrolyzed p-nitrophenylphosphate (p-NPP) to p-nitrophenol (p-NP) at a rate of 12.78 +/- 0.53 nmol p-NP per h per mg hyphal dry weight. The values of Vmax and apparent Km for p-NPP hydrolyses were measured as 17.89 +/- 0.92 nmol p-NP per h per mg hyphal dry weight and 1.57 +/- 0.26 mmol/l, respectively. This activity was inhibited at increased pH, a finding compatible with an acid phosphatase. The enzymatic activity was strongly inhibited by classical inhibitors of acid phosphatases such as sodium orthovanadate (Ki = 4.23 micromol/l), sodium molybdate (Ki = 7.53 micromol/l) and sodium fluoride (Ki = 126.78 micromol/l) in a dose-dependent manner. Levamizole (1 mmol/l) and sodium tartrate (10 mmol/l), had no effect on the enzyme activity. Cytochemical localization of the acid phosphatase showed electrondense cerium phosphate deposits on the cell wall, as visualized by transmission electron microscopy. Phosphatase activity in F. pedrosoi seems to be associated with parasitism, as sclerotic cells, which are the fungal forms mainly detected in chromoblastomycosis lesions, showed much higher activities than conidia and mycelia did. A strain of F. pedrosoi recently isolated from a human case of chromoblastomycosis also showed increased enzyme activity, suggesting that the expression of surface phosphatases may be stimulated by interaction with the host.
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Affiliation(s)
- L F Kneipp
- Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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40
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Alviano DS, Kneipp LF, Lopes AH, Travassos LR, Meyer-Fernandes JR, Rodrigues ML, Alviano CS. Differentiation of Fonsecaea pedrosoi mycelial forms into sclerotic cells is induced by platelet-activating factor. Res Microbiol 2003; 154:689-95. [PMID: 14643407 DOI: 10.1016/j.resmic.2003.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Platelet-activating factor (PAF) has been shown to induce the differentiation of several cell types. In this work, we evaluated the effects of PAF on the formation of sclerotic cells of Fonsecaea pedrosoi, the major causative agent of chromoblastomycosis. Cell differentiation was evaluated by light and electron microscopy, which showed that treatment of mycelial forms with PAF results in the generation of sclerotic bodies with typical morphological characteristics. Biochemical features of PAF-induced sclerotic cells were also analyzed and compared with those from sclerotic forms induced by propranolol, a previously described differentiating agent of F. pedrosoi. Chemical analyses of lipid and carbohydrate components from PAF- or propranolol-induced sclerotic bodies revealed that palmitic, stearic, oleic and linoleic acids were the major fatty acid components, while glucose, mannose, galactose and rhamnose were detected as the principal sugar constituents in these cells. Surface carbohydrate components of PAF- and propranolol-induced sclerotic cells were also evaluated, by flow cytometry analysis with twelve different lectins. The profile of reactivity of PAF- or propranolol-induced fungal cells with lectins was also very similar. Hydrolysis of the synthetic substrate p-nitrophenylphosphate by fungal cells demonstrated that the addition of PAF or propranolol to the mycelial cultures similarly promotes a significant increase in ecto-phosphatase activity. These results indicate that the differentiation of F. pedrosoi mycelial cells induced by PAF generates authentic sclerotic forms, as confirmed by the analysis of morphological and biochemical attributes. Since PAF is synthesized in normal conditions by the human host, these observations may have a correlation with the differentiation of F. pedrosoi in vivo.
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Affiliation(s)
- Daniela S Alviano
- Instituto de Microbiologia Professor Paulo de Góes, Departamento de Microbiologia Geral, Universidade Federal do Rio de Janeiro, Cidade, Rio de Janeiro, Brazil.
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Alves-Ferreira M, Dutra PML, Lopes AHCS, Ferreira-Pereira A, Scofano HM, Meyer-Fernandes JR. Magnesium-Dependent Ecto-ATP Diphosphohydrolase Activity in Herpetomonas muscarum muscarum. Curr Microbiol 2003; 47:265-71. [PMID: 14629005 DOI: 10.1007/s00284-002-3975-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the present work we characterized the ecto-ATP diphosphohydrolase activity of the trypanosomatid parasite Herpetomonas muscarum muscarum. This parasite hydrolyzed ATP at a rate of 15.52 nmol Pi/mg protein/min and this activity reached a maximum at pH 7.5. Classical inhibitors of acid phosphatases, such as sodium orthovanadate (NaVO3), sodium fluoride (NaF), and ammonium molybdate presented no effect on this activity. MgCl2, ZnCl2, and MnCl2 stimulated the ATP hydrolysis by H. m. muscarum. The ecto-ATPase activity was insensitive to oligomycin and sodium azide, two inhibitors of mitochondrial Mg-ATPase, bafilomycin A1, a V-ATPase inhibitor, ouabain, a Na(+)+K+-ATPase inhibitor and to levamizole, an inhibitor of alkaline phosphatase. An extracellular impermeant inhibitor 4,4'-diisothiocyanostylbene 2',2'-disulfonic acid (DIDS) and a inhibitor of some ecto-ATPases, suramin, which is also a competitive antagonist of P2-purinergic receptors, promoted a great inhibition on the ATP hydrolysis. This enzyme is able to hydrolysis ATP, ADP, UTP, and UDP, but not GTP, GDP, CTP, or CDP. ADP inhibited the enzymatic activity in a concentration dependent manner, reaching 70% inhibition.
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Affiliation(s)
- M Alves-Ferreira
- Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz, Fundaçao Oswaldo Cruz, Rio de Janeiro, RJ, 21045-900, Brazil
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42
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de Jesus JB, Podlyska TM, Hampshire A, Lopes CS, Vannier-Santos MA, Meyer-Fernandes JR. Characterization of an ecto-phosphatase activity in the human parasite Trichomonas vaginalis. Parasitol Res 2002; 88:991-7. [PMID: 12375165 DOI: 10.1007/s00436-001-0583-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2001] [Accepted: 12/11/2001] [Indexed: 10/27/2022]
Abstract
We have characterized phosphatase activity present on the external surface of Trichomonas vaginalis, using intact living parasites. This enzyme hydrolyzes the substrate p-nitrophenylphosphate (p-NPP) at a rate of 134.3+/-14.8 nmol Pi/h per 10(7) cells. This phosphatase activity decreased by increasing the pH from 6.8 to 8.4, a pH range in which cell viability was maintained for at least 1 h. Experiments using classical inhibitors of acid phosphatases, such as ammonium molybdate and sodium fluoride, as well as inhibitors of phosphotyrosine phosphatase, such as sodium orthovanadate, [monoperoxo(picolinato)oxovanadate(V)] (mpV-PIC) and [potassiumbisperoxo(1,10-phenanthroline)oxovanadate(V)] (bpV-PHEN), showed a decrease in this phosphatase activity, with different patterns of inhibition. Cytochemical analysis showed the localization of this enzyme on the parasite surface (cell body and flagellum) and in intracellular vacuoles. Phosphatase reaction products were also observed in exocytosed membrane-bound material.
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Affiliation(s)
- J B de Jesus
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil
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43
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Santos ALS, Souto-Padrón T, Alviano CS, Lopes AHSC, Soares RMA, Meyer-Fernandes JR. Secreted phosphatase activity induced by dimethyl sulfoxide in Herpetomonas samuelpessoai. Arch Biochem Biophys 2002; 405:191-8. [PMID: 12220532 DOI: 10.1016/s0003-9861(02)00403-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A phosphatase activity of the trypanosomatid parasite Herpetomonas samuelpessoai was characterized using intact living cells. The effects of dimethyl sulfoxide (DMSO) on this activity were investigated. This phosphatase activity (2.53+/-0.01 nmol P(i)/mg protein x min) was linear with cell density and with time for at least 60 min. The optimum pH for the H. samuelpessoai phosphatase lies in the acid range. This phosphatase activity was inhibited by metal chelators and classical phosphatase inhibitors. A robust stimulation of the phosphatase activity was observed when the flagellates were grown in the presence of 4% DMSO, both when intact flagellates and when culture supernatant from those cells were assayed, as observed by biochemical and cytochemical analysis. We also demonstrate that DMSO induced the secretion and/or shedding of this phosphatase to the extracellular medium, with a possible involvement of protein kinase C in this process.
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Affiliation(s)
- André L S Santos
- Instituto de Microbiologia Prof. Paulo de Góes, CCS, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, RJ 21941-590, Rio de Janeiro, Brazil
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Abstract
In this work, we describe the ability of living Tritrichomonas foetus to hydrolyze extracellular ATP. The addition of MgCl(2) to the assay medium increased the ecto-ATPase activity in a dose-dependent manner. At 5mM ATP, half maximal stimulation of ATP hydrolysis was obtained with 0.46mM MgCl(2). The ecto-ATPase activity was also stimulated by MnCl(2) and CaCl(2), but not by SrCl(2). The Mg(2+)-dependent ATPase presents two apparent K(m) values for Mg-ATP(2-) (K(m1)=0.03 mM and K(m2)=2.01 mM). ATP was the best substrate for this enzyme, although other nucleotides such as ITP, CTP, UTP also produced high reaction rates. GTP produced a low reaction rate and ADP was not a substrate for this enzyme. The Mg(2+)-dependent ecto-ATPase activity was insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin A(1), ouabain, furosemide, vanadate, molybdate, sodium fluoride and levamizole. The acid phosphatase inhibitors (vanadate and molybdate) inhibited about 60-70% of the Mg(2+)-independent ecto-ATPase activity, suggesting that the ATP hydrolysis measured in the absence of any metal divalent could, at least in part, also be catalyzed by an ecto-phosphatase present in this cell. In order to confirm the observed Mg(2+)-dependent activity as an ecto-ATPase, we used an impermeant inhibitor, 4,4'-diisothiocyanostylbene-2',2'-disulfonic acid (DIDS) as well as suramin, an antagonist of P(2) purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg(2+)-dependent ATPase activity in a dose-dependent manner. This ecto-ATPase was stimulated by more than 90% by 50mM D-galactose. Since previous results showed that D-galactose exposed on the surface of host cells is involved with T. foetus adhesion, the Mg(2+)-dependent ecto-ATPase may be involved with cellular adhesion and possible pathogenicity.
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Affiliation(s)
- José B Jesus
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21541-590, Rio de Janeiro, RJ, Brazil
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45
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Bernardes CF, Fagian MM, Meyer-Fernandes JR, Castilho RF, Vercesi AE. Suramin inhibits respiration and induces membrane permeability transition in isolated rat liver mitochondria. Toxicology 2001; 169:17-23. [PMID: 11696406 DOI: 10.1016/s0300-483x(01)00477-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Suramin, a polysulfonated naphthylamine, caused a dose dependent inhibition of carbonyl cyanide p-(tri-fluoromethoxy)phenylhydrazone-stimulated respiration supported either by succinate or a cocktail of alphaketoglutarate, malate and isocitrate in isolated rat liver mitochondria. The half-maximum effect was obtained at 40 and 140 microM suramin for NADH- or FADH(2)-linked substrates, respectively. The respiration supported by N,N,N'N'-tetramethyl-p-phenylenediamine oxidation was unaffected by suramin (<or=500 microM). The latter respiratory substrate was used in the studies at examining the effects of suramin on the permeability properties of the inner mitochondrial membrane. These experiments provided evidence that suramin causes Ca(2+)-dependent mitochondrial swelling sensitive to the mitochondrial permeability transition (MPT) inhibitors cyclosporin A, ADP and Mg(2+). In addition, suramin decreased the content of reduced mitochondrial membrane protein thiols suggesting that thiol oxidation is the mechanism underlying suramin-induced MPT.
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Affiliation(s)
- C F Bernardes
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP 13083-970, Brazil.
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46
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Dutra PM, Dias FA, Rodrigues CO, Romeiro A, Attias M, De Souza W, Lopes AH, Meyer-Fernandes JR. Platelet-activating factor modulates a secreted phosphatase activity of the trypanosomatid parasite Herpetomonas muscarum muscarum. Curr Microbiol 2001; 43:288-92. [PMID: 11683365 DOI: 10.1007/s002840010303] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In the present work we characterized the secreted phosphatase activity of the trypanosomatid parasite Herpetomonas muscarum muscarum. This housefly parasite hydrolyzed p-nitrophenylphosphate at a rate of 10.26 nmol Pi/mg protein/min. Classical inhibitors of acid phosphatases, such as sodium orthovanadate (NaVO3), sodium fluoride (NaF), and ammonium molybdate promoted a decrease in this phosphatase activity. When the parasites were assayed in the presence of sodium tartrate, an inhibitor of Leishmania spp-secreted acid phosphatases, this activity was drastically diminished. Cytochemical analysis showed the localization of this enzyme on the external surface and in the flagellar pocket of these parasites. Sodium tartrate inhibited this reaction, confirming the biochemical data. Platelet-activating factor (PAF) inhibited the phosphatase activity determined in the supernatant of living H. m. muscarum.
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Affiliation(s)
- P M Dutra
- Instituto de Microbiologia Professor Paulo de Góes, UFRJ, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
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47
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Abstract
In this study we report the effects of sulfated polysaccharides on the ecto-ATPase activity of intact cells of Leishmania tropica. Increasing concentrations of dextran sulfate stimulated progressively the ecto-ATPase activity, but did not modify other ecto-enzymes present on the surface of this parasite, such as 5'nucleotidase, 3'nucleotidase and a membrane-bound acid phosphatase activity. This stimulation was not observed when other sulfated polysaccharides such as chondroitin sulfates and heparin were tested. It depends on size and charge of the dextran sulfated molecule. When the cells were incubated in the presence of dextran sulfate Mr 8,000; 40,000 and 500,000 the stimulation of the ecto-ATPase activity was 11%; 23%; and 63%, respectively, and the stimulation was not observed when desulfated dextran (Mr 40,000) was used. The effects of dextran sulfate also depend on pH of the medium. At pH 7.5, the stimulation was over 60%, whereas at pH 8.5 only 25%. The effects of dextran sulfate 500,000 on the ecto-ATPase activity was totally abolished by spermidine and partially by putrescine, two polyamines synthesized and released by Leishmania.
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Affiliation(s)
- C E Peres-Sampaio
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, RJ, Brazil
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48
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Berrêdo-Pinho M, Peres-Sampaio CE, Chrispim PP, Belmont-Firpo R, Lemos AP, Martiny A, Vannier-Santos MA, Meyer-Fernandes JR. A Mg-dependent ecto-ATPase in Leishmania amazonensis and its possible role in adenosine acquisition and virulence. Arch Biochem Biophys 2001; 391:16-24. [PMID: 11414680 DOI: 10.1006/abbi.2001.2384] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The plasma membrane of cells contains enzymes whose active sites face the external medium rather than the cytoplasm. The activities of these enzymes, referred to as ectoenzymes, can be measured using living cells. In this work we describe the ability of living promastigotes of Leishmania amazonensis to hydrolyze extracellular ATP. In these intact parasites whose viability was assessed before and after the reactions by motility and by trypan blue dye exclusion, there was a low level of ATP hydrolysis in the absence of any divalent metal (5.39 +/- 0.71 nmol P(i)/h x 10(7) cells). The ATP hydrolysis was stimulated by MgCl(2) and the Mg-dependent ecto-ATPase activity was 30.75 +/- 2.64 nmol P(i)/h x 10(7) cells. The Mg-dependent ecto-ATPase activity was linear with cell density and with time for at least 60 min. The addition of MgCl(2) to extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. At 5 mM ATP, half-maximal stimulation of ATP hydrolysis was obtained with 1.21 mM MgCl(2). This stimulatory activity was also observed when MgCl(2) was replaced by MnCl(2), but not by CaCl(2) or SrCl(2). The apparent K(m) for Mg-ATP(2-) was 0.98 mM and free Mg(2+) did not increase the ecto-ATPase activity. In the pH range from 6.8 to 8.4, in which the cells were viable, the acid phosphatase activity decreased, while the Mg(2+)-dependent ATPase activity increased. This ecto-ATPase activity was insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin A(1), ouabain, furosemide, vanadate, molybdate, sodium fluoride, tartrate, and levamizole. To confirm that this Mg-dependent ATPase was an ecto-ATPase, we used an impermeant inhibitor, 4,4'-diisothiocyanostylbene 2',2'-disulfonic acid as well as suramin, an antagonist of P(2) purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg(2+)-dependent ATPase activity in a dose-dependent manner. A comparison between the Mg(2+)-dependent ATPase activity of virulent and avirulent promastigotes showed that avirulent promastigotes were less efficient than the virulent promastigotes in hydrolyzing ATP.
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Affiliation(s)
- M Berrêdo-Pinho
- Departamento de Bioquímica Médica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ihlo do Fundão, 21541-590, Rio de Janeiro, RJ, Brazil
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49
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Dutra PM, Dias FA, Santos MA, Rodrigues CO, Romeiro A, Attias M, De Souza W, Lopes AH, Meyer-Fernandes JR. Secreted phosphatase activities in trypanosomatid parasites of plants modulated by platelet-activating factor. Phytopathology 2001; 91:408-414. [PMID: 18943854 DOI: 10.1094/phyto.2001.91.4.408] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT The secreted phosphatase activities of two trypanosomatid parasites were characterized and compared with supernatants of living cells. The plant parasite Phytomonas françai and the phytophagous hemipteran parasite Herpetomonas sp. hydrolyzed p-nitrophenylphosphate at a rate of 15.54 and 6.51 nmol Pi/mg of protein per min, respectively. Sodium orthovanadate (N(a)VO(3)) and sodium fluoride (NaF) decreased the phosphatase activities. The phosphatase activity of P. françai was drastically diminished (73% inhibition) in the presence of sodium tartrate, whereas the phosphatase activity of Herpetomonas sp. was inhibited by 23%. Cytochemical analysis showed the localization of these enzymes on the external surface and in the flagellar pocket of the two trypanosomatids. Sodium tartrate inhibited this reaction, confirming the biochemical data. Platelet-activating factor modulated the phosphatase activities, inhibiting P. françai activity and stimulating Herpetomonas sp. phosphatase activity.
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50
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Saad-Nehme J, Silva JL, Meyer-Fernandes JR. Osmolytes protect mitochondrial F(0)F(1)-ATPase complex against pressure inactivation. Biochim Biophys Acta 2001; 1546:164-70. [PMID: 11257519 DOI: 10.1016/s0167-4838(01)00137-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We have previously reported that carbohydrates and polyols protect different enzymes against thermal inactivation and deleterious effects promoted by guanidinium chloride and urea. Here, we show that these osmolytes (carbohydrates, polyols and methylamines) protect mitochondrial F(0)F(1)-ATPase against pressure inactivation. Pressure stability of mitochondrial F(0)F(1)-ATPase complex by osmolytes was studied using preparations of membrane-bound submitochondrial particles depleted or containing inhibitor protein (IP). Hydrostatic pressure in the range from 0.5 to 2.0 kbar causes inactivation of submitochondrial particles depleted of IP (AS particles). However, the osmolytes prevent pressure inactivation of the complex in a dose-dependent manner, remaining up to 80% of hydrolytic activity at the highest osmolyte concentration. Submitochondrial particles containing IP (MgATP-SMP) exhibit low ATPase activity and dissociation of IP increases the hydrolytic activity of the enzyme. MgATP-SMP subjected to pressure (2.2 kbar, for 1 h) and then preincubated at 42 degrees C to undergo activation did not have an increase in activity. However, particles pressurized in the presence of 1.5 M of sucrose or 3.0 M of glucose were protected and after preincubation at 42 degrees C, showed an activation very similarly to those kept at 1 bar. In accordance with the preferential hydration theory, we believe that osmolytes reduce to a minimum the surface of the macromolecule to be hydrated and oppose pressure-induced alterations of the native fold that are driven by hydration forces.
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Affiliation(s)
- J Saad-Nehme
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro (UFRJ), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil
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