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Grahl MVC, Andrade BDS, Perin APA, Neves GA, Duarte LDS, Uberti AF, Hohl KS, Follmer C, Carlini CR. Could the Urease of the Gut Bacterium Proteus mirabilis Play a Role in the Altered Gut-Brain Talk Associated with Parkinson's Disease? Microorganisms 2023; 11:2042. [PMID: 37630602 PMCID: PMC10459573 DOI: 10.3390/microorganisms11082042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/01/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
Intestinal dysbiosis seems to play a role in neurodegenerative pathologies. Parkinson's disease (PD) patients have an altered gut microbiota. Moreover, mice treated orally with the gut microbe Proteus mirabilis developed Parkinson's-like symptoms. Here, the possible involvement of P. mirabilis urease (PMU) and its B subunit (PmUreβ) in the pathogenesis of PD was assessed. Purified proteins were given to mice intraperitoneally (20 μg/animal/day) for one week. Behavioral tests were conducted, and brain homogenates of the treated animals were subjected to immunoassays. After treatment with PMU, the levels of TNF-α and IL-1β were measured in Caco2 cells and cellular permeability was assayed in Hek 293. The proteins were incubated in vitro with α-synuclein and examined via transmission electron microscopy. Our results showed that PMU treatment induced depressive-like behavior in mice. No motor deficits were observed. The brain homogenates had an increased content of caspase-9, while the levels of α-synuclein and tyrosine hydroxylase decreased. PMU increased the pro-inflammatory cytokines and altered the cellular permeability in cultured cells. The urease, but not the PmUreβ, altered the morphology of α-synuclein aggregates in vitro, forming fragmented aggregates. We concluded that PMU promotes pro-inflammatory effects in cultured cells. In vivo, PMU induces neuroinflammation and a depressive-like phenotype compatible with the first stages of PD development.
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Affiliation(s)
- Matheus V. C. Grahl
- Graduate Program in Medicine and Health Sciences and Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre 90610-000, RS, Brazil; (M.V.C.G.); (A.F.U.)
- School of Health Sciences, University Center Ritter dos Reis, Porto Alegre 90840-440, RS, Brazil
| | - Brenda da Silva Andrade
- Laboratory of Molecular Pharmacology, Institute of Biomedical Sciences, Health Sciences Center, Federal University of Rio de Janeiro, Rio de Janeiro 21944-590, RJ, Brazil; (B.d.S.A.); (G.A.N.); (L.d.S.D.)
| | - Ana Paula A. Perin
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Federal University of Rio Grande do Sul, Porto Alegre 91501-970, RS, Brazil;
| | - Gilda A. Neves
- Laboratory of Molecular Pharmacology, Institute of Biomedical Sciences, Health Sciences Center, Federal University of Rio de Janeiro, Rio de Janeiro 21944-590, RJ, Brazil; (B.d.S.A.); (G.A.N.); (L.d.S.D.)
| | - Laura de Souza Duarte
- Laboratory of Molecular Pharmacology, Institute of Biomedical Sciences, Health Sciences Center, Federal University of Rio de Janeiro, Rio de Janeiro 21944-590, RJ, Brazil; (B.d.S.A.); (G.A.N.); (L.d.S.D.)
| | - Augusto Frantz Uberti
- Graduate Program in Medicine and Health Sciences and Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre 90610-000, RS, Brazil; (M.V.C.G.); (A.F.U.)
| | - Kelvin Siqueira Hohl
- Graduate Program in Biological Sciences—Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil;
| | - Cristian Follmer
- Laboratory of Biological Chemistry of Neurodegenerative Disorders, Institute of Chemistry, Department of Physical-Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, RJ, Brazil;
| | - Celia Regina Carlini
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil
- National Institute of Science and Technology in Brain Diseases, Excitotoxity and Neuroprotection (INCT-EN), Porto Alegre 90035-003, RS, Brazil
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Grahl MVC, Uberti AF, Broll V, Bacaicoa-Caruso P, Meirelles EF, Carlini CR. Proteus mirabilis Urease: Unsuspected Non-Enzymatic Properties Relevant to Pathogenicity. Int J Mol Sci 2021; 22:ijms22137205. [PMID: 34281258 PMCID: PMC8268090 DOI: 10.3390/ijms22137205] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 12/22/2022] Open
Abstract
Infection by Proteus mirabilis causes urinary stones and catheter incrustation due to ammonia formed by urease (PMU), one of its virulence factors. Non-enzymatic properties, such as pro-inflammatory and neurotoxic activities, were previously reported for distinct ureases, including that of the gastric pathogen Helicobacter pylori. Here, PMU was assayed on isolated cells to evaluate its non-enzymatic properties. Purified PMU (nanomolar range) was tested in human (platelets, HEK293 and SH-SY5Y) cells, and in murine microglia (BV-2). PMU promoted platelet aggregation. It did not affect cellular viability and no ammonia was detected in the cultures’ supernatants. PMU-treated HEK293 cells acquired a pro-inflammatory phenotype, producing reactive oxygen species (ROS) and cytokines IL-1β and TNF-α. SH-SY5Y cells stimulated with PMU showed high levels of intracellular Ca2+ and ROS production, but unlike BV-2 cells, SH-SY5Y did not synthesize TNF-α and IL-1β. Texas Red-labeled PMU was found in the cytoplasm and in the nucleus of all cell types. Bioinformatic analysis revealed two bipartite nuclear localization sequences in PMU. We have shown that PMU, besides urinary stone formation, can potentially contribute in other ways to pathogenesis. Our data suggest that PMU triggers pro-inflammatory effects and may affect cells beyond the renal system, indicating a possible role in extra-urinary diseases.
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Affiliation(s)
- Matheus V. C. Grahl
- Laboratory of Neurotoxins, Brain Institute of Rio Grande do Sul (BRAINS) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, RS, Brazil; (M.V.C.G.); (A.F.U.)
| | - Augusto F. Uberti
- Laboratory of Neurotoxins, Brain Institute of Rio Grande do Sul (BRAINS) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, RS, Brazil; (M.V.C.G.); (A.F.U.)
| | - Valquiria Broll
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, RS, Brazil;
| | - Paula Bacaicoa-Caruso
- Laboratory of Neurotoxins, Brain Institute of Rio Grande do Sul (BRAINS) and Graduate Program in Cellular and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, RS, Brazil;
| | - Evelin F. Meirelles
- Laboratory of Neurotoxins, Brain Institute of Rio Grande do Sul (BRAINS), Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, RS, Brazil;
| | - Celia R. Carlini
- Laboratory of Neurotoxins, Brain Institute of Rio Grande do Sul (BRAINS) and School of Medicine, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre CEP 90610-000, RS, Brazil
- Correspondence: ; Tel.: +55-51-33205986
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3
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Zhu A, Zhang T, Wang Q. The phytochemistry, pharmacokinetics, pharmacology and toxicity of Euphorbia semen. JOURNAL OF ETHNOPHARMACOLOGY 2018; 227:41-55. [PMID: 30144497 DOI: 10.1016/j.jep.2018.08.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/07/2018] [Accepted: 08/19/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Euphorbia semen, the dried and ripe seed of Euphorbia lathyris Linnaeus, is widely cultivated for traditional medicine use. This semen is used to expel water, help with phlegm retention, promote blood circulation, remove blood stasis, cure tinea and scabies, and treat amenorrhea, snakebites, terminal schistosomiasis, anuria and constipation. AIM OF THE REVIEW This review provides updated, comprehensive and categorized information on the local and traditional uses, phytochemistry, pharmacokinetics, pharmacological activities and toxicity of Euphorbia semen. Future research to deepen the recognition and utilization of Euphorbia semen is proposed. MATERIALS AND METHODS This article conducted a literature review on information about Euphorbia semen in multiple Internet databases, including PubMed, Web of Science, Wiley, Science Direct, Elsevier, ACS publications, SciFinder, Google Scholar and China National Knowledge Internet, until March of 2018. In this manuscript, a number of books, PhD and MSc dissertations, and Chinese Pharmacopeia were also used as references. RESULTS Approximately 240 chemical constituents have been isolated and identified from Euphorbia semen, namely, diterpenoids, coumarins, flavonoids, fatty acids, amino acids, and steroids. Pharmacokinetic study focused on investigating absorption, distribution, metabolism and excretion (ADME). The chemical constituents have extensive pharmacological effects, such as diuresis and anti-hyperuricaemia, anti-inflammation, antiviral, anticancer, antioxidant, antipigmentation, anti-platelet aggregation and anti-allergic activities, as well as hepatoprotection and neuroprotection. The toxicity of Euphorbia semen, including acute toxicity, target organ irritation and cocareinogenic effects, have been reported, and the detoxification methods are reviewed. CONCLUSION Euphorbia semen has extensive pharmacological activity and excellent clinical value, along with intense intestinal irritation. Although plenty of chemical constituents have been isolated and identified, the exact pharmacological and toxicological mechanisms still need to be explored.
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Affiliation(s)
- An Zhu
- Department of Toxicology, School of Public Health, Peking University, No. 38 Xueyuan Road, Haidian District, Beijing 100191, China.
| | - Tao Zhang
- Department of Toxicology, School of Public Health, Peking University, No. 38 Xueyuan Road, Haidian District, Beijing 100191, China.
| | - Qi Wang
- Department of Toxicology, School of Public Health, Peking University, No. 38 Xueyuan Road, Haidian District, Beijing 100191, China; Key Laboratory of State Administration of Traditional Chinese Medicine for Compatibility Toxicology, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China.
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Kappaun K, Piovesan AR, Carlini CR, Ligabue-Braun R. Ureases: Historical aspects, catalytic, and non-catalytic properties - A review. J Adv Res 2018; 13:3-17. [PMID: 30094078 PMCID: PMC6077230 DOI: 10.1016/j.jare.2018.05.010] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 12/11/2022] Open
Abstract
Urease (urea amidohydrolase, EC 3.5.1.5) is a nickel-containing enzyme produced by plants, fungi, and bacteria that catalyzes the hydrolysis of urea into ammonia and carbamate. Urease is of historical importance in Biochemistry as it was the first enzyme ever to be crystallized (1926). Finding nickel in urease's active site (1975) was the first indication of a biological role for this metal. In this review, historical and structural features, kinetics aspects, activation of the metallocenter and inhibitors of the urea hydrolyzing activity of ureases are discussed. The review also deals with the non-enzymatic biological properties, whose discovery 40 years ago started a new chapter in the study of ureases. Well recognized as virulence factors due to the production of ammonia and alkalinization in diseases by urease-positive microorganisms, ureases have pro-inflammatory, endocytosis-inducing and neurotoxic activities that do not require ureolysis. Particularly relevant in plants, ureases exert insecticidal and fungitoxic effects. Data on the jack bean urease and on jaburetox, a recombinant urease-derived peptide, have indicated that interactions with cell membrane lipids may be the basis of the non-enzymatic biological properties of ureases. Altogether, with this review we wanted to invite the readers to take a second look at ureases, very versatile proteins that happen also to catalyze the breakdown of urea into ammonia and carbamate.
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Affiliation(s)
- Karine Kappaun
- Brain Institute (InsCer), Pontifícia Universidade Católica do Rio Grande do Sul, Avenida Ipiranga 6690, Prédio 63, Porto Alegre, RS CEP 90610-000, Brazil
- Graduate Program in Medicine and Health Sciences, School of Medicine, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil
| | - Angela Regina Piovesan
- Brain Institute (InsCer), Pontifícia Universidade Católica do Rio Grande do Sul, Avenida Ipiranga 6690, Prédio 63, Porto Alegre, RS CEP 90610-000, Brazil
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Celia Regina Carlini
- Brain Institute (InsCer), Pontifícia Universidade Católica do Rio Grande do Sul, Avenida Ipiranga 6690, Prédio 63, Porto Alegre, RS CEP 90610-000, Brazil
- Graduate Program in Medicine and Health Sciences, School of Medicine, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil
| | - Rodrigo Ligabue-Braun
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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5
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Scopel-Guerra A, Olivera-Severo D, Staniscuaski F, Uberti AF, Callai-Silva N, Jaeger N, Porto BN, Carlini CR. The Impact of Helicobacter pylori Urease upon Platelets and Consequent Contributions to Inflammation. Front Microbiol 2017; 8:2447. [PMID: 29312166 PMCID: PMC5733092 DOI: 10.3389/fmicb.2017.02447] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/24/2017] [Indexed: 12/22/2022] Open
Abstract
Gastric infection by Helicobacter pylori is considered a risk factor for gastric and duodenal cancer, and extragastric diseases. Previous data have shown that, in a non-enzymatic way, H. pylori urease (HPU) activates neutrophils to produce ROS and also induces platelet aggregation, requiring ADP secretion modulated by the 12-lipoxygenase pathway, a signaling cascade also triggered by the physiological agonist collagen. Here we investigated further the effects on platelets of recombinant versions of the holoenzyme HPU, and of its two subunits (HpUreA and HpUreB). Although HpUreA had no aggregating activity on platelets, it partially inhibited collagen-induced aggregation. HpUreB induced platelet aggregation in the nanomolar range, and also interfered dose-dependently on both collagen- and ADP-induced platelet aggregation. HPU-induced platelet aggregation was inhibited by antibodies against glycoprotein VI (GPVI), the main collagen receptor in platelets. Flow cytometry analysis revealed exposure of P-selectin in HPU-activated platelets. Anti-glycoprotein IIbIIIa (GPIIbIIIa) antibodies increased the binding of FITC-labeled HPU to activated platelets, whereas anti-GPVI did not. Evaluation of post-transcriptional events in HPU-activated platelets revealed modifications in the pre-mRNA processing of pro-inflammatory proteins, with increased levels of mRNAs encoding IL-1β and CD14. We concluded that HPU activates platelets probably through its HpUreB subunit. Activation of platelets by HPU turns these cells into a pro-inflammatory phenotype. Altogether, our data suggest that H. pylori urease, besides allowing bacterial survival within the gastric mucosa, may have an important, and so far overlooked, role in gastric inflammation mediated by urease-activated neutrophils and platelets.
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Affiliation(s)
- Adriele Scopel-Guerra
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Deiber Olivera-Severo
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Department of Biology, Universidade Regional Integrada do Alto Uruguai e das Missões, São Luiz Gonzaga, Brazil
| | - Fernanda Staniscuaski
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Department of Molecular Biology and Biotechnology, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Augusto F Uberti
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Institute of Biology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Natália Callai-Silva
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Natália Jaeger
- Institute of Biomedical Research, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Bárbara N Porto
- Institute of Biomedical Research, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Celia R Carlini
- Brain Institute (BRAINS-InsCer), Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
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Fruttero LL, Moyetta NR, Uberti AF, Grahl MVC, Lopes FC, Broll V, Feder D, Carlini CR. Humoral and cellular immune responses induced by the urease-derived peptide Jaburetox in the model organism Rhodnius prolixus. Parasit Vectors 2016; 9:412. [PMID: 27455853 PMCID: PMC4960889 DOI: 10.1186/s13071-016-1710-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/18/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although the entomotoxicity of plant ureases has been reported almost 20 years ago, their insecticidal mechanism of action is still not well understood. Jaburetox is a recombinant peptide derived from one of the isoforms of Canavalia ensiformis (Jack Bean) urease that presents biotechnological interest since it is toxic to insects of different orders. Previous studies of our group using the Chagas disease vector and model insect Rhodnius prolixus showed that the treatment with Jack Bean Urease (JBU) led to hemocyte aggregation and hemolymph darkening, among other effects. In this work, we employed cell biology and biochemical approaches to investigate whether Jaburetox would induce not only cellular but also humoral immune responses in this species. RESULTS The findings indicated that nanomolar doses of Jaburetox triggered cation-dependent, in vitro aggregation of hemocytes of fifth-instar nymphs and adults. The use of specific eicosanoid synthesis inhibitors revealed that the cellular immune response required cyclooxygenase products since indomethacin prevented the Jaburetox-dependent aggregation whereas baicalein and esculetin (inhibitors of the lipoxygenases pathway) did not. Cultured hemocytes incubated with Jaburetox for 24 h showed cytoskeleton disorganization, chromatin condensation and were positive for activated caspase 3, an apoptosis marker, although their phagocytic activity remained unchanged. Finally, in vivo treatments by injection of Jaburetox induced both a cellular response, as observed by hemocyte aggregation, and a humoral response, as seen by the increase of spontaneous phenoloxidase activity, a key enzyme involved in melanization and defense. On the other hand, the humoral response elicited by Jaburetox injections did not lead to an increment of antibacterial or lysozyme activities. Jaburetox injections also impaired the clearance of the pathogenic bacteria Staphylococcus aureus from the hemolymph leading to increased mortality, indicating a possible immunosuppression induced by treatment with the peptide. CONCLUSIONS In our experimental conditions and as part of its toxic action, Jaburetox activates some responses of the immune system of R. prolixus both in vivo and in vitro, although this induction does not protect the insects against posterior bacterial infections. Taken together, these findings contribute to the general knowledge of insect immunity and shed light on Jaburetox's mechanism of action.
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Affiliation(s)
- Leonardo L Fruttero
- Brain Institute (INSCER) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil. .,Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. .,Instituto do Cérebro (InsCer) - Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6690, prédio 63, CEP 90610-000, Porto Alegre, RS, Brazil.
| | - Natalia R Moyetta
- Brain Institute (INSCER) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Augusto F Uberti
- Brain Institute (INSCER) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Matheus V Coste Grahl
- Brain Institute (INSCER) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fernanda C Lopes
- Brain Institute (INSCER) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Valquiria Broll
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Denise Feder
- Department of General Biology l, Insect Biology Laboratory, Universidade Federal Fluminense, Niteroi, RJ, Brazil
| | - Celia R Carlini
- Brain Institute (INSCER) and Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Department of Biophysics, Biosciences Institute (IB), Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Carlini CR, Ligabue-Braun R. Ureases as multifunctional toxic proteins: A review. Toxicon 2015; 110:90-109. [PMID: 26690979 DOI: 10.1016/j.toxicon.2015.11.020] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 11/09/2015] [Accepted: 11/26/2015] [Indexed: 12/21/2022]
Abstract
Ureases are metalloenzymes that hydrolyze urea into ammonia and carbon dioxide. They were the first enzymes to be crystallized and, with them, the notion that enzymes are proteins became accepted. Novel toxic properties of ureases that are independent of their enzyme activity have been discovered in the last three decades. Since our first description of the neurotoxic properties of canatoxin, an isoform of the jack bean urease, which appeared in Toxicon in 1981, about one hundred articles have been published on "new" properties of plant and microbial ureases. Here we review the present knowledge on the non-enzymatic properties of ureases. Plant ureases and microbial ureases are fungitoxic to filamentous fungi and yeasts by a mechanism involving fungal membrane permeabilization. Plant and at least some bacterial ureases have potent insecticidal effects. This entomotoxicity relies partly on an internal peptide released upon proteolysis of ingested urease by insect digestive enzymes. The intact protein and its derived peptide(s) are neurotoxic to insects and affect a number of other physiological functions, such as diuresis, muscle contraction and immunity. In mammal models some ureases are acutely neurotoxic upon injection, at least partially by enzyme-independent effects. For a long time bacterial ureases have been recognized as important virulence factors of diseases by urease-producing microorganisms. Ureases activate exocytosis in different mammalian cells recruiting eicosanoids and Ca(2+)-dependent pathways, even when their ureolytic activity is blocked by an irreversible inhibitor. Ureases are chemotactic factors recognized by neutrophils (and some bacteria), activating them and also platelets into a pro-inflammatory "status". Secretion-induction by ureases may play a role in fungal and bacterial diseases in humans and other animals. The now recognized "moonlighting" properties of these proteins have renewed interest in ureases for their biotechnological potential to improve plant defense against pests and as potential targets to ameliorate diseases due to pathogenic urease-producing microorganisms.
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Affiliation(s)
- Celia R Carlini
- Brain Institute (Instituto do Cérebro-INSCER), Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Center of Biotechnology, Universidade Federal do Rio Grande do Sul Porto Alegre, RS, Brazil.
| | - Rodrigo Ligabue-Braun
- Center of Biotechnology, Universidade Federal do Rio Grande do Sul Porto Alegre, RS, Brazil
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Medeiros-Silva M, Franck WL, Borba MP, Pizzato SB, Strodtman KN, Emerich DW, Stacey G, Polacco JC, Carlini CR. Soybean ureases, but not that of Bradyrhizobium japonicum, are involved in the process of soybean root nodulation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:3517-24. [PMID: 24716625 DOI: 10.1021/jf5000612] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ureases are abundant in plants, bacteria, and in the soil, but their role in signaling between soybean and soil microorganisms has not been investigated. The bacterium Bradyrhizobium japonicum forms nitrogen-fixing nodules on soybean roots. Here, we evaluated the role(s) of ureases in the process of soybean nodulation. Chemotaxis assays demonstrated that soybean and jack bean ureases were more chemotactic toward bacterial cells than the corresponding plant lectins. The eu1-a,eu4 soybean, deficient in urease isoforms, formed fewer but larger nodules than the wild-type, regardless of the bacterial urease phenotype. Leghemoglobin production in wild-type plants was higher and peaked earlier than in urease-deficient plants. Inhibition of urease activity in wild-type plants did not result in the alterations seen in mutated plants. We conclude that soybean urease(s) play(s) a role in the soybean-B. japonicum symbiosis, which is independent of its ureolytic activity. Bacterial urease does not play a role in nodulation.
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Affiliation(s)
- Mônica Medeiros-Silva
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology and #Department of Biophysics and Center of Biotechnology, Universidade Federal do Rio Grande do Sul , Porto Alegre, Rio Grande do Sul CEP 91501-970, Brazil
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9
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Piovesan AR, Martinelli AHS, Ligabue-Braun R, Schwartz JL, Carlini CR. Canavalia ensiformis urease, Jaburetox and derived peptides form ion channels in planar lipid bilayers. Arch Biochem Biophys 2014; 547:6-17. [PMID: 24583269 DOI: 10.1016/j.abb.2014.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 01/22/2023]
Abstract
Ureases catalyze the hydrolysis of urea into NH3 and CO2. They are synthesized by plants, fungi and bacteria but not by animals. Ureases display biological activities unrelated to their enzymatic activity, i.e., platelet and neutrophil activation, fungus inhibition and insecticidal effect. Urease from Canavalia ensiformis (jack bean) is toxic to several hemipteran and coleopteran insects. Jaburetox is an insecticidal fragment derived from jack bean urease. Among other effects, Jaburetox has been shown to interact with lipid vesicles. In this work, the ion channel activity of C. ensiformis urease, Jaburetox and three deletion mutants of Jaburetox (one lacking the N-terminal region, one lacking the C-terminal region and one missing the central β-hairpin) were tested on planar lipid bilayers. All proteins formed well resolved, highly cation-selective channels exhibiting two conducting states whose conductance ranges were 7-18pS and 32-79pS, respectively. Urease and the N-terminal mutant of Jaburetox were more active at negative potentials, while the channels of the other peptides did not display voltage-dependence. This is the first direct demonstration of the capacity of C. ensiformis urease and Jaburetox to permeabilize membranes through an ion channel-based mechanism, which may be a crucial step of their diverse biological activities, including host defense.
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Affiliation(s)
- Angela R Piovesan
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil
| | - Anne H S Martinelli
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil; Department of Biophysics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil
| | - Rodrigo Ligabue-Braun
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil
| | - Jean-Louis Schwartz
- Groupe d'étude des protéines membranaires (GÉPROM, FQR-S) and Department of Physiology, Faculty of Medicine, Université de Montréal, Montreal, Quebec H3C 3J7, Canada; Centre SÈVE (FQR-NT), Université de Sherbrooke, Sherbrooke, Quebec J1K 2R, Canada.
| | - Celia R Carlini
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil; Department of Biophysics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil.
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10
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Defferrari MS, da Silva R, Orchard I, Carlini CR. Jack bean (Canavalia ensiformis) urease induces eicosanoid-modulated hemocyte aggregation in the Chagas' disease vector Rhodnius prolixus. Toxicon 2014; 82:18-25. [PMID: 24561121 DOI: 10.1016/j.toxicon.2014.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 01/29/2014] [Accepted: 02/04/2014] [Indexed: 12/25/2022]
Abstract
Ureases are multifunctional proteins that display biological activities independently of their enzymatic function, such as induction of exocytosis and insecticidal effects. Rhodnius prolixus, a major vector of Chagas' disease, is a model for studies on the entomotoxicity of jack bean urease (JBU). We have previously shown that JBU induces the production of eicosanoids in isolated tissues of R. prolixus. In insects, the immune response comprises cellular and humoral reactions, and is centrally modulated by eicosanoids. Cyclooxygenase products signal immunity in insects, mainly cellular reactions, such as hemocyte aggregation. In searching for a link between JBU's toxic effects and immune reactions in insects, we have studied the effects of this toxin on R. prolixus hemocytes. JBU triggers aggregation of hemocytes after injection into the hemocoel and when applied to isolated cells. On in vitro assays, the eicosanoid synthesis inhibitors dexamethasone (phospholipase A2 indirect inhibitor) and indomethacin (cyclooxygenase inhibitor) counteracted JBU's effect, indicating that eicosanoids, more specifically cyclooxygenase products, are likely to mediate the aggregation response. Contrarily, the inhibitors esculetin and baicalein were inactive, suggesting that lipoxygenase products are not involved in JBU's effect. Extracellular calcium was also necessary for JBU's effect, in agreement to other cell models responsive to ureases. A progressive darkening of the medium of JBU-treated hemocytes was observed, suggestive of a humoral response. JBU was immunolocalized in the cultured cells upon treatment along with cytoskeleton damage. The highest concentration of JBU tested on cultured cells also led to nuclei aggregation of adherent hemocytes. This is the first time urease has been shown to affect insect hemocytes, contributing to our understanding of the entomotoxic mechanisms of action of this protein.
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Affiliation(s)
- M S Defferrari
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
| | - R da Silva
- Department of Biology, McMaster University, Hamilton, ON, Canada.
| | - I Orchard
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.
| | - C R Carlini
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto do Cérebro - InsCer, Pontificia Universidade Católica do Rio Grande do Sul, and Department of Biophysics, Biosciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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11
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A phospholipase A2 gene is linked to Jack bean urease toxicity in the Chagas' disease vector Rhodnius prolixus. Biochim Biophys Acta Gen Subj 2014; 1840:396-405. [DOI: 10.1016/j.bbagen.2013.09.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 07/26/2013] [Accepted: 09/11/2013] [Indexed: 01/10/2023]
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12
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McMahon GS, Jones CI, Hayes PD, Naylor AR, Goodall AH. Transient heparin-induced platelet activation linked to generation of platelet 12-lipoxygenase. Findings from a randomised controlled trial. Thromb Haemost 2013; 109:1099-107. [PMID: 23494053 DOI: 10.1160/th12-11-0793] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 01/31/2013] [Indexed: 11/05/2022]
Abstract
Previously we demonstrated that heparin administration during carotid endarterectomy (CEA) caused a marked, but transient increase in platelet aggregation to arachidonic acid (AA) and adenosine diphosphate (ADP), despite effective platelet cyclo-oxygenase-1 (COX-1) inhibition with aspirin. Here we investigated the metabolism of AA via platelet 12-lipoxygenase (12-LOX) as a possible mediator of the observed transient aspirin resistance, and compared the effects of unfractionated (UFH) and low-molecular-weight (LMWH) heparin. A total of 43 aspirinated patients undergoing CEA were randomised in the trial to 5,000 IU UFH (n=22) or 2,500 IU LMWH (dalteparin, n=21). Platelet aggregation to AA (4x10⁻³) and ADP (3x10⁻⁶) was determined, and the products of the COX-1 and 12-LOX pathways; thromboxane B₂ (TXB₂) and 12-hydroxyeicosatretraenoic acid (12-HETE) were measured in plasma, and in material released from aggregating platelets.Aggregation to AA increased significantly (~10-fold) following heparinisation (p<0.0001), irrespective of heparin type (p=0.33). Significant, but smaller (~2-fold) increases in aggregation to ADP were also seen, which were significantly lower in the platelets of patients randomised to LMWH (p<0.0001). Plasma levels of TxB2 did not rise following heparinisation (p=0.93), but 12-HETE increased significantly in the patients' plasma, and released from platelets stimulated in vitro withADP, with both heparin types (p<0.0001). The magnitude of aggregation to ADP correlated with 12-HETE generation (p=0.03). Heparin administration during CEA generates AA that is metabolised to 12-HETE via the 12-LOX pathway, possibly explaining the phenomenon of transient heparin-induced platelet activation. LMWH has less effect on aggregation and 12-HETE generation than UFH when the platelets are stimulated with ADP.
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Affiliation(s)
- Greg S McMahon
- Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield Hospital, Leicester, LE3 9QP, UK
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13
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Uberti AF, Olivera-Severo D, Wassermann GE, Scopel-Guerra A, Moraes JA, Barcellos-de-Souza P, Barja-Fidalgo C, Carlini CR. Pro-inflammatory properties and neutrophil activation by Helicobacter pylori urease. Toxicon 2013; 69:240-9. [PMID: 23466444 DOI: 10.1016/j.toxicon.2013.02.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 12/25/2012] [Accepted: 02/05/2013] [Indexed: 01/25/2023]
Abstract
The gastric pathogen Helicobacter pylori produces large amounts of urease, whose enzyme activity enables the bacterium to survive in the stomach. We have previously shown that ureases display enzyme-independent effects in mammalian models, most through lipoxygenases-mediated pathways. Here, we evaluated potential pro-inflammatory properties of H. pylori urease (HPU). Mouse paw edema and activation of human neutrophils were tested using a purified, cell-free, recombinant HPU. rHPU induced paw edema with intense neutrophil infiltration. In vitro 100 nM rHPU was chemotactic to human neutrophils, inducing production of reactive oxygen species. rHPU-activated neutrophils showed increased lifespan, with inhibition of apoptosis accompanied by alterations of Bcl-XL and Bad contents. These effects of rHPU persisted in the absence of enzyme activity. rHPU-induced paw edema, neutrophil chemotaxis and apoptosis inhibition reverted in the presence of the lipoxygenase inhibitors esculetin or AA861. Neutrophils exposed to rHPU showed increased content of lipoxygenase(s) and no alteration of cyclooxygenase(s). Altogether, our data indicate that HPU, besides allowing the bacterial survival in the stomach, could play an important role in the pathogenesis of the gastrointestinal inflammatory disease caused by H. pylori.
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Affiliation(s)
- Augusto F Uberti
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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14
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Plant ureases and related peptides: understanding their entomotoxic properties. Toxins (Basel) 2012; 4:55-67. [PMID: 22474566 PMCID: PMC3317107 DOI: 10.3390/toxins4020055] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/05/2012] [Accepted: 01/11/2012] [Indexed: 01/08/2023] Open
Abstract
Recently, ureases were included in the arsenal of plant defense proteins, alongside many other proteins with biotechnological potential such as insecticides. Isoforms of Canavalia ensiformis urease (canatoxin—CNTX and jack bean urease—JBURE-I) are toxic to insects of different orders. This toxicity is due in part to the release of a 10 kDa peptide from the native protein, by cathepsin-like enzymes present in the insect digestive tract. The entomotoxic peptide, Jaburetox-2Ec, exhibits potent insecticidal activity against several insects, including many resistant to the native ureases. JBURE-I and Jaburetox-2Ec cause major alterations of post-feeding physiological processes in insects, which contribute to, or can be the cause of, their entomotoxic effect. An overview of the current knowledge on plant urease processing and mechanisms of action in insects is presented in this review.
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15
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Follmer C. Ureases as a target for the treatment of gastric and urinary infections. J Clin Pathol 2010; 63:424-30. [PMID: 20418234 DOI: 10.1136/jcp.2009.072595] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Urease is known to be a major contributor to pathologies induced by Helicobacter pylori and Proteus species. In H pylori, urease allows the bacteria to survive in an acidic gastric environment during colonisation, playing an important role in the pathogenesis of gastric and peptic ulcers. Ureolytic activity also results in the production of ammonia in close proximity to the gastric epithelium, causing cell damage and inflammation. In the case of Proteus species (notably Proteus mirabilis) infection, stones are formed due to the presence of ammonia and carbon dioxide released by urease action. In addition, the ammonia released is able to damage the glycosaminoglycan layer, which protects the urothelial surface against bacterial infection. In this context, the administration of urease inhibitors may be an effective therapy for urease-dependent pathogenic bacteria. This is a review of the role of ureases in H pylori and Proteus species infections, focussing on the biochemical and clinical aspects of the most promising and/or potent urease inhibitors for the treatment of gastric and urinary tract infections.
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Affiliation(s)
- C Follmer
- Department of Physical Chemistry, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
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16
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Stanisçuaski F, Te Brugge V, Carlini CR, Orchard I. Jack bean urease alters serotonin-induced effects on Rhodnius prolixus anterior midgut. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1078-1086. [PMID: 20223243 DOI: 10.1016/j.jinsphys.2010.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 03/01/2010] [Accepted: 03/01/2010] [Indexed: 05/28/2023]
Abstract
Urease isoforms from jack bean seeds are toxic to insects, and this entomotoxic effect is mostly due to the release of a peptide by insect digestive enzymes. We previously demonstrated that jack bean urease (JBU) has antidiuretic effects on Rhodnius prolixus Malpighian tubules, decreasing the serotonin-stimulated secretion of fluid. Now, we evaluate the toxicity of the intact JBU and its effect on R. prolixus anterior midgut, to further elucidate the mechanism of action of JBU in insects. JBU decreases the serotonin-induced fluid transport by the anterior midgut in vitro when injected into the lumen. A decrease in the levels of cAMP is observed in tissues treated with JBU (in the presence of serotonin). JBU also causes a dose-dependent increase in the frequency of serotonin-induced contractions in the anterior midgut, but does not alter the frequency of spontaneous contractions. The cyclooxygenase inhibitor indomethacin and the prostaglandin antagonist AH6809 block JBU's potentiation of serotonin-induced contractions, indicating that prostaglandins might act as second messengers for JBU action. Prostaglandin E(2) (PGE(2)) increases the frequency of serotonin-induced contractions, again supporting the role of prostaglandins as second messengers for JBU action. JBU and PGE(2) increase cGMP levels in the anterior midgut, indicating that this molecule might also be part of the JBU pathway.
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Affiliation(s)
- F Stanisçuaski
- Department of Biophysics, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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17
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Crystal structure of the first plant urease from jack bean: 83 years of journey from its first crystal to molecular structure. J Mol Biol 2010; 400:274-83. [PMID: 20471401 DOI: 10.1016/j.jmb.2010.05.009] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 05/03/2010] [Accepted: 05/06/2010] [Indexed: 11/23/2022]
Abstract
Urease, a nickel-dependent metalloenzyme, is synthesized by plants, some bacteria, and fungi. It catalyzes the hydrolysis of urea into ammonia and carbon dioxide. Although the amino acid sequences of plant and bacterial ureases are closely related, some biological activities differ significantly. Plant ureases but not bacterial ureases possess insecticidal properties independent of its ureolytic activity. To date, the structural information is available only for bacterial ureases although the jack bean urease (Canavalia ensiformis; JBU), the best-studied plant urease, was the first enzyme to be crystallized in 1926. To better understand the biological properties of plant ureases including the mechanism of insecticidal activity, we initiated the structural studies on some of them. Here, we report the crystal structure of JBU, the first plant urease structure, at 2.05 A resolution. The active-site architecture of JBU is similar to that of bacterial ureases containing a bi-nickel center. JBU has a bound phosphate and covalently modified residue (Cys592) by beta-mercaptoethanol at its active site, and the concomitant binding of multiple inhibitors (phosphate and beta-mercaptoethanol) is not observed so far in bacterial ureases. By correlating the structural information of JBU with the available biophysical and biochemical data on insecticidal properties of plant ureases, we hypothesize that the amphipathic beta-hairpin located in the entomotoxic peptide region of plant ureases might form a membrane insertion beta-barrel as found in beta-pore-forming toxins.
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18
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Wassermann GE, Olivera-Severo D, Uberti AF, Carlini CR. Helicobacter pylori urease activates blood platelets through a lipoxygenase-mediated pathway. J Cell Mol Med 2009; 14:2025-34. [PMID: 19754669 PMCID: PMC3823284 DOI: 10.1111/j.1582-4934.2009.00901.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The bacterium Helicobacter pylori causes peptic ulcers and gastric cancer in human beings by mechanisms yet not fully understood. H. pylori produces urease which neutralizes the acidic medium permitting its survival in the stomach. We have previously shown that ureases from jackbean, soybean or Bacillus pasteurii induce blood platelet aggregation independently of their enzyme activity by a pathway requiring platelet secretion, activation of calcium channels and lipoxygenase-derived eicosanoids. We investigated whether H. pylori urease displays platelet-activating properties and defined biochemical pathways involved in this phenomenon. For that the effects of purified recombinant H. pylori urease (HPU) added to rabbit platelets were assessed turbidimetrically. ATP secretion and production of lipoxygenase metabolites by activated platelets were measured. Fluorescein-labelled HPU bound to platelets but not to erythrocytes. HPU induced aggregation of rabbit platelets (ED(50) 0.28 microM) accompanied by ATP secretion. No correlation was found between platelet activation and ureolytic activity of HPU. Platelet aggregation was blocked by esculetin (12-lipoxygenase inhibitor) and enhanced approximately 3-fold by indomethacin (cyclooxygenase inhibitor). A metabolite of 12-lipoxygenase was produced by platelets exposed to HPU. Platelet responses to HPU did not involve platelet-activating factor, but required activation of verapamil-inhibitable calcium channels. Our data show that purified H. pylori urease activates blood platelets at submicromolar concentrations. This property seems to be common to ureases regardless of their source (plant or bacteria) or quaternary structure (single, di- or tri-chain proteins). These properties of HPU could play an important role in pathogenesis of gastrointestinal and associated cardiovascular diseases caused by H. pylori.
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Affiliation(s)
- German E Wassermann
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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19
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Follmer C. Insights into the role and structure of plant ureases. PHYTOCHEMISTRY 2008; 69:18-28. [PMID: 17706733 DOI: 10.1016/j.phytochem.2007.06.034] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 06/11/2007] [Accepted: 06/28/2007] [Indexed: 05/11/2023]
Abstract
The broad distribution of ureases in leguminous seeds, as well as the accumulation pattern of the protein during seed maturation, are suggestive of an important physiological role for this enzyme. Since the isolation and characterization of jack bean urease by Sumner in 1926, many investigations have been dedicated to the structural and biological features of this enzyme; nevertheless, many questions still remain. It has been reported that ureases from plants (jack bean and soybean seeds) display biological properties unrelated to their ureolytic activity, notably a high insecticidal activity against Coleoptera (beetles) and Hemiptera (bugs), suggesting that ureases might be involved in plant defense. Besides the insecticidal activity, canatoxin, a jack bean urease isoform, causes convulsions and death in mice and rats, induces indirect hemagglutination (hemilectin activity) and promotes exocytosis in several cell types. Not only plant ureases but also some microbial ureases (found in Bacillus pasteurii and Helicobacter pylori) are able to induce activation of platelets in a process mediated by lipoxygenase-derived metabolites. This review summarizes the biological and structural properties of plant ureases, compares them with those displayed by bacterial ureases, and discusses the significance of these findings.
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Affiliation(s)
- Cristian Follmer
- Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio de Janeiro, CT, Bloco A S410, Rio de Janeiro 21941-909, Brazil.
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20
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Kälvegren H, Andersson J, Grenegård M, Bengtsson T. Platelet activation triggered by Chlamydia pneumoniae is antagonized by 12-lipoxygenase inhibitors but not cyclooxygenase inhibitors. Eur J Pharmacol 2007; 566:20-7. [PMID: 17459368 DOI: 10.1016/j.ejphar.2007.03.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 03/02/2007] [Accepted: 03/06/2007] [Indexed: 10/23/2022]
Abstract
Chlamydia pneumoniae is a respiratory pathogen that has been linked to cardiovascular disease. We have recently shown that C. pneumoniae activates platelets, leading to oxidation of low-density lipoproteins. The aim of the present study was to evaluate the inhibitory effects of different pharmacological agents on platelet aggregation and secretion induced by C. pneumoniae. Platelet interaction with C. pneumoniae was studied by analyzing platelet aggregation and ATP-secretion with Lumi-aggregometry. Platelet aggregation and ATP-secretion induced by C. pneumoniae was markedly inhibited by the NO-donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP), an effect that was counteracted by the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Pre-treatment of platelets with the 12-lipoxygenase (12-LOX) inhibitors cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate (CDC) and 5,6,7-trikydroxyflavone (baicalein) completely blocked the activation, whereas the cyclooxygenase (COX) inhibitors 2-acetyloxybenzoic acid (aspirin) and (8E)-8-[hydroxy-(pyridin-2-ylamino)methylidene]-9-methyl-10,10-dioxo-10$l;(6)thia-9-azabicyclo[4.4.0]deca-1,3,5-trien-7-one (piroxicam) had no inhibitory effects. Opposite to C. pneumoniae-induced activation, platelets stimulated by collagen were inhibited by the COX-inhibitors but were unaffected by the 12-LOX-inhibitors. The platelet activating factor (PAF) antagonist Ginkgolide B blocked the C. pneumoniae-induced platelet activation, whereas the responses to collagen were unaffected. Furthermore, the P2Y1 and P2Y12 purinergic receptor antagonists 2'-deoxy-N6-methyladenosine 3',5'-bisphosphate (MRS2179) and N(6)-(2-methyl-thioethyl)-2-(3,3,3-trifluoropropylthio)-beta,gamma-dichloromethylene-ATP (cangrelor) inhibited the aggregation and secretion caused by C. pneumoniae. It is well-known that the efficacy of COX inhibitors in the prevention and treatment of cardiovascular disease varies between different patients, and that patients with low responses to aspirin have a higher risk to encounter cardiovascular events. The findings in this study showing that platelets stimulated by C. pneumoniae are unaffected by COX inhibitors but sensitive to 12-LOX inhibitors, may thus be of importance in future management of atherosclerosis and thrombosis.
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Affiliation(s)
- Hanna Kälvegren
- Division of Pharmacology, Department of Medicine and Care, Cardiovascular Inflammation Research Centre, Faculty of Health Sciences, Linköping University, SE-581 85 Linköping, Sweden.
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