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Lacerda-Abreu MA, Dick CF, Meyer-Fernandes JR. The Role of Inorganic Phosphate Transporters in Highly Proliferative Cells: From Protozoan Parasites to Cancer Cells. MEMBRANES 2022; 13:42. [PMID: 36676849 PMCID: PMC9860751 DOI: 10.3390/membranes13010042] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/01/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023]
Abstract
In addition to their standard inorganic phosphate (Pi) nutritional function, Pi transporters have additional roles in several cells, including Pi sensing (the so-called transceptor) and a crucial role in Pi metabolism, where they control several phenotypes, such as virulence in pathogens and tumour aggressiveness in cancer cells. Thus, intracellular Pi concentration should be tightly regulated by the fine control of intake and storage in organelles. Pi transporters are classified into two groups: the Pi transporter (PiT) family, also known as the Pi:Na+ symporter family; and the Pi:H+ symporter (PHS) family. Highly proliferative cells, such as protozoan parasites and cancer cells, rely on aerobic glycolysis to support the rapid generation of biomass, which is equated with the well-known Warburg effect in cancer cells. In protozoan parasite cells, Pi transporters are strongly associated with cell proliferation, possibly through their action as intracellular Pi suppliers for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. Similarly, the growth rate hypothesis (GRH) proposes that the high Pi demands of tumours when achieving accelerated proliferation are mainly due to increased allocation to P-rich nucleic acids. The purpose of this review was to highlight recent advances in understanding the role of Pi transporters in unicellular eukaryotes and tumorigenic cells, correlating these roles with metabolism in these cells.
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Affiliation(s)
- Marco Antonio Lacerda-Abreu
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Claudia Fernanda Dick
- National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - José Roberto Meyer-Fernandes
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
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Carvalho-Kelly LF, Dick CF, Rocco-Machado N, Gomes-Vieira AL, Paes-Vieira L, Meyer-Fernandes JR. Anaerobic ATP synthesis pathways and inorganic phosphate transport and their possible roles in encystment in Acanthamoeba castellanii. Cell Biol Int 2022; 46:1288-1298. [PMID: 35673988 DOI: 10.1002/cbin.11830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 12/12/2022]
Abstract
Acanthamoeba castellanii is the etiological agent of amoebic keratitis and is present in the environment in trophozoite or cyst forms. Both forms can infect the vertebrate host and colonize different tissues. The high resistance of cysts to standard drugs used in clinics contributes to the lack of effective treatments. Therefore, in this context, studies have emerged to understand cyst physiology and metabolism. Phosphate transporters are proteins responsible for the uptake of extracellular inorganic phosphate and transport to the cytosol. This work aims to verify the relationship between Pi transport and energetic metabolism in cysts of A. castellanii. The phosphate uptake ratio was higher in cysts compared with trophozoites. Recently, three sequences related to phosphate transporters have been identified in the A. castellanii genome (AcPHS1, AcPHS2, and AcPHS3); the messenger RNA expression levels of which differ depending on the amoeba life form. Pi uptake in cysts displayed peak activity at alkaline pH, whereas Pi transport in trophozoites was not affected in the same pH ranges. Cysts harbor a low-affinity Pi transport system (K0,5 and Vmax values of 1.76 ± 0.26 mM and 104.6 ± 6.3 nmol Pi × h-1 × 106 cells) compared to the trophozoite phosphate transport system. Pi transport seems important for anaerobic adenosine triphosphate synthesis in cysts, which initially occurs through the glycolytic pathway and subsequently through the pyruvate ferredoxin oxidoreductase pathway. Altogether, these results suggest that contrary to that previously postulated, cysts are active metabolic forms, and, as noted in trophozoites, phosphate uptake is important for energetic metabolism.
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Affiliation(s)
| | - Claudia Fernanda Dick
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Nathalia Rocco-Machado
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - André Luiz Gomes-Vieira
- Departamento de Bioquímica, Instituto de Química, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Lisvane Paes-Vieira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
- Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
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Carvalho-de-Araújo AD, Carvalho-Kelly LF, Dick CF, Meyer-Fernandes JR. Inorganic phosphate transporter in Giardia duodenalis and its possible role in ATP synthesis. Mol Biochem Parasitol 2022; 251:111504. [PMID: 35843419 DOI: 10.1016/j.molbiopara.2022.111504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/14/2022] [Accepted: 07/13/2022] [Indexed: 10/17/2022]
Abstract
Giardia duodenalis is a flagellated protozoan that inhabits vertebrate host intestines, causing the disease known as giardiasis. Similar to other parasites, G. duodenalis must take advantage of environmental resources to survive, such as inorganic phosphate (Pi) availability. Pi is an anionic molecule and an essential nutrient for all organisms because it participates in the biosynthesis of biomolecules, energy storage, and cellular structure formation. The first step in Pi metabolism is its uptake through specific transporters on the plasma membrane. We identified a symporter H+:Pi-type ORF sequence in the G. duodenalis genome (GenBank ID: GL50803_5164), named GdPho84, which is homologous to Saccharomyces cerevisiae PHO84. In trophozoites, Pi transport was linear for up to 15 min, and the cell density was 3 × 107 cells/ml. Physiological variations in pH (6.4-8.0) did not influence Pi uptake. This Pi transporter had a high affinity, with K0.5 = 67.7 ± 7.1 µM Pi. SCH28080 (inhibitor of H+, K+-ATPase), bafilomycin A1 (inhibitor of vacuolar H+-ATPase), and FCCP (H+ ionophore) were able to inhibit Pi transport, indicating that an H+ gradient in the cell powered uphill Pi movement. PAA, an H+-dependent Pi transport inhibitor, reduced cell proliferation, Pi transport activity, and GdPHO48 mRNA levels. Pi starvation stimulated membrane potential-sensitive Pi uptake coupled to H+ fluxes, increased GdPho84 expression, and reduced intracellular ATP levels. These events indicate that these cells had an increased capacity to internalize Pi as a compensatory mechanism compared to cells maintained in control medium conditions. Internalized Pi can be used in glycolytic metabolism once iodoacetamide (GAPDH inhibitor) inhibits Pi influx. Together, these results reinforce the hypothesis that Pi is a crucial nutrient for G. duodenalis energy metabolism.
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Affiliation(s)
| | - Luiz Fernando Carvalho-Kelly
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil
| | - Claudia F Dick
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
| | - José Roberto Meyer-Fernandes
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
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Gomes MT, Paes-Vieira L, Gomes-Vieira AL, Cosentino-Gomes D, da Silva APP, Giarola NLL, Da Silva D, Sola-Penna M, Galina A, Meyer-Fernandes JR. 3-Bromopyruvate: A new strategy for inhibition of glycolytic enzymes in Leishmania amazonensis. Exp Parasitol 2021; 229:108154. [PMID: 34481863 DOI: 10.1016/j.exppara.2021.108154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 05/14/2021] [Accepted: 08/28/2021] [Indexed: 11/29/2022]
Abstract
The compound 3-bromopyruvate (3-BrPA) is well-known and studies from several researchers have demonstrated its involvement in tumorigenesis. It is an analogue of pyruvic acid that inhibits ATP synthesis by inhibiting enzymes from the glycolytic pathway and oxidative phosphorylation. In this work, we investigated the effect of 3-BrPA on energy metabolism of L. amazonensis. In order to verify the effect of 3-BrPA on L. amazonensis glycolysis, we measured the activity level of three glycolytic enzymes located at different points of the pathway: (i) glucose kinases, step 1, (ii) glyceraldehyde 3-phosphate dehydrogenase (GAPDH), step 6, and (iii) enolase, step 9. 3-BrPA, in a dose-dependent manner, significantly reduced the activity levels of all the enzymes. In addition, 3-BrPA treatment led to a reduction in the levels of phosphofruto-1-kinase (PFK) protein, suggesting that the mode of action of 3-BrPA involves the downregulation of some glycolytic enzymes. Measurement of ATP levels in promastigotes of L. amazonensis showed a significant reduction in ATP generation. The O2 consumption was also significantly inhibited in promastigotes, confirming the energy depletion effect of 3-BrPA. When 3-BrPA was added to the cells at the beginning of growth cycle, it significantly inhibited L. amazonensis proliferation in a dose-dependent manner. Furthermore, the ability to infect macrophages was reduced by approximately 50% when promastigotes were treated with 3-BrPA. Taken together, these studies corroborate with previous reports which suggest 3-BrPA as a potential drug against pathogenic microorganisms that are reliant on glucose catabolism for ATP supply.
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Affiliation(s)
- Marta Teixeira Gomes
- Division of Pulmonary, Critical Care, Sleep and Occupational Medicine, Department of Medicine, Indiana University, Indianapolis, IN, USA; Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Lisvane Paes-Vieira
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - André Luiz Gomes-Vieira
- Instituto de Química, Departamento de Bioquímica, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - Daniela Cosentino-Gomes
- Instituto de Química, Departamento de Bioquímica, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - Ana Paula Pereira da Silva
- Instituto de Química, Departamento de Bioquímica, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - Naira Ligia Lima Giarola
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Daniel Da Silva
- Laboratório de Enzimologia e Controle do Metabolismo, Departamento de Biotecnologia Farmacêutica, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Mauro Sola-Penna
- Laboratório de Enzimologia e Controle do Metabolismo, Departamento de Biotecnologia Farmacêutica, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Antonio Galina
- Laboratorio de Bioenergética e Fisiologia Mitocondrial, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Medica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, RJ, Brazil
| | - José Roberto Meyer-Fernandes
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, 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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Asady B, Dick CF, Ehrenman K, Sahu T, Romano JD, Coppens I. A single Na+-Pi cotransporter in Toxoplasma plays key roles in phosphate import and control of parasite osmoregulation. PLoS Pathog 2021; 16:e1009067. [PMID: 33383579 PMCID: PMC7817038 DOI: 10.1371/journal.ppat.1009067] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 01/20/2021] [Accepted: 10/14/2020] [Indexed: 11/22/2022] Open
Abstract
Inorganic ions such as phosphate, are essential nutrients required for a broad spectrum of cellular functions and regulation. During infection, pathogens must obtain inorganic phosphate (Pi) from the host. Despite the essentiality of phosphate for all forms of life, how the intracellular parasite Toxoplasma gondii acquires Pi from the host cell is still unknown. In this study, we demonstrated that Toxoplasma actively internalizes exogenous Pi by exploiting a gradient of Na+ ions to drive Pi uptake across the plasma membrane. The Na+-dependent phosphate transport mechanism is electrogenic and functionally coupled to a cipargarmin sensitive Na+-H+-ATPase. Toxoplasma expresses one transmembrane Pi transporter harboring PHO4 binding domains that typify the PiT Family. This transporter named TgPiT, localizes to the plasma membrane, the inward buds of the endosomal organelles termed VAC, and many cytoplasmic vesicles. Upon Pi limitation in the medium, TgPiT is more abundant at the plasma membrane. We genetically ablated the PiT gene, and ΔTgPiT parasites are impaired in importing Pi and synthesizing polyphosphates. Interestingly, ΔTgPiT parasites accumulate 4-times more acidocalcisomes, storage organelles for phosphate molecules, as compared to parental parasites. In addition, these mutants have a reduced cell volume, enlarged VAC organelles, defects in calcium storage and a slightly alkaline pH. Overall, these mutants exhibit severe growth defects and have reduced acute virulence in mice. In survival mode, ΔTgPiT parasites upregulate several genes, including those encoding enzymes that cleave or transfer phosphate groups from phosphometabolites, transporters and ions exchangers localized to VAC or acidocalcisomes. Taken together, these findings point to a critical role of TgPiT for Pi supply for Toxoplasma and also for protection against osmotic stresses. Inorganic phosphate (Pi) is indispensable for the biosynthesis of key cellular components, and is involved in many metabolic and signaling pathways. Transport across the plasma membrane is the first step in the utilization of Pi. The import mechanism of Pi by the intracellular parasite Toxoplasma is unknown. We characterized a transmembrane, high-affinity Na+-Pi cotransporter, named TgPiT, expressed by the parasite at the plasma membrane for Pi uptake. Interestingly, TgPiT is also localized to inward buds of the endosomal VAC organelles and some cytoplasmic vesicles. Loss of TgPiT results in a severe reduction in Pi internalization and polyphosphate levels, but stimulation of the biogenesis of phosphate-enriched acidocalcisomes. ΔTgPiT parasites have a shrunken cell body, enlarged VAC organelles, poor release of stored calcium and a mildly alkaline pH, suggesting a role for TgPiT in the maintenance of overall ionic homeostasis. ΔTgPiT parasites are poorly infectious in vitro and in mice. The mutant appears to partially cope with the absence of TgPiT by up-regulating genes coding for ion transporters and enzymes catalyzing phosphate group transfer. Our data highlight a scenario in which the role of TgPiT in Pi and Na+ transport is functionally coupled with osmoregulation activities central to sustain Toxoplasma survival.
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Affiliation(s)
- Beejan Asady
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Claudia F. Dick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Karen Ehrenman
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Tejram Sahu
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Julia D. Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
- * E-mail:
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Carvalho-Kelly LF, Pralon CF, Rocco-Machado N, Nascimento MT, Carvalho-de-Araújo AD, Meyer-Fernandes JR. Acanthamoeba castellanii phosphate transporter (AcPHS) is important to maintain inorganic phosphate influx and is related to trophozoite metabolic processes. J Bioenerg Biomembr 2020; 52:93-102. [PMID: 31965457 DOI: 10.1007/s10863-020-09822-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/03/2020] [Indexed: 10/25/2022]
Abstract
Acanthamoeba castellanii is a free-living amoeba and the etiological agent of granulomatous amoebic encephalitis and amoebic keratitis. A. castellanii can be present as trophozoites or cysts. The trophozoite is the vegetative form of the cell and has great infective capacity compared to the cysts, which are the dormant form that protect the cell from environmental changes. Phosphate transporters are a group of proteins that are able to internalize inorganic phosphate from the extracellular to intracellular medium. Plasma membrane phosphate transporters are responsible for maintaining phosphate homeostasis, and in some organisms, regulating cellular growth. The aim of this work was to biochemically characterize the plasma membrane phosphate transporter in A. castellanii and its role in cellular growth and metabolism. To measure inorganic phosphate (Pi) uptake, trophozoites were grown in liquid PYG medium at 28 °C for 2 days. The phosphate uptake was measured by the rapid filtration of intact cells incubated with 0.5 μCi of 32Pi for 1 h. The Pi transport was linear as a function of time and exhibited Michaelis-Menten kinetics with a Km = 88.78 ± 6.86 μM Pi and Vmax = 547.5 ± 16.9 Pi × h-1 × 10-6 cells. A. castellanii presented linear phosphate uptake up to 1 h with a cell density ranging from 1 × 105 to 2 × 106 amoeba × ml-1. The Pi uptake was higher in the acidic pH range than in the alkaline range. The oxygen consumption of living trophozoites increased according to Pi addition to the extracellular medium. When the cells were treated with FCCP, no effect from Pi on the oxygen flow was observed. The addition of increasing Pi concentrations not only increased oxygen consumption but also increased the intracellular ATP pool. These phenomena were abolished when the cells were treated with FCCP or exposed to hypoxia. Together, these results reinforce the hypothesis that Pi is a key nutrient for Acanthamoeba castellanii metabolism.
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Affiliation(s)
- Luiz Fernando Carvalho-Kelly
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | - Clara Ferreira Pralon
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | - Nathalia Rocco-Machado
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | | | - Ayra Diandra Carvalho-de-Araújo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil. .,Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil.
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