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Johnsen N, Christensen MG, Hamilton AD, Praetorius H. HlyA cause platelet activation and neutrophil/ monocyte interaction during urosepsis. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Nedeljkovic N. Complex regulation of ecto-5'-nucleotidase/CD73 and A 2AR-mediated adenosine signaling at neurovascular unit: A link between acute and chronic neuroinflammation. Pharmacol Res 2019; 144:99-115. [PMID: 30954629 DOI: 10.1016/j.phrs.2019.04.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/01/2019] [Accepted: 04/03/2019] [Indexed: 12/20/2022]
Abstract
The review summarizes available data regarding the complex regulation of CD73 at the neurovascular unit (NVU) during neuroinflammation. Based on available data we propose the biphasic pattern of CD73 regulation at NVU, with an early attenuation and a postponed up-regulation of CD73 activity. Transient attenuation of CD73 activity on leukocyte/vascular endothelium and leukocyte/astrocyte surface, required for the initiation of a neuroinflammatory response, may be effectuated either by catalytic inhibition of CD73 and/or by shedding of the CD73 molecule from the cell surface, while postponed induction of CD73 is effectuated by transcriptional up-regulation of Nt5e and posttranslational modifications. Neuroinflammatory conditions are also associated with significant enhancement and gain-of-function of A2AR-mediated adenosine signaling. However, in contrast to the temporary prevalence of A2AR over A1R signaling during an acute inflammatory response, prolonged induction of A2AR and resulting perpetual CD73/A2AR coupling may be a contributing factors in the transition between acute and chronic neuroinflammation. Thus, pharmacological targeting of the CD73/A2AR axis may attenuate inflammatory response and ameliorate neurological deficits in chronic neuroinflammatory conditions.
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Affiliation(s)
- Nadezda Nedeljkovic
- Department of General Physiology and Biophysics, Faculty of Biology University of Belgrade, Studentski trg 3, Belgrade 11001, Serbia.
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Martins JD, Silva A, Ferreira I, Gonçalo M, Custódio JBA, Lopes MC, Domingues MRM, Neves BM, Cruz MT. Adenosine diphosphate involvement in THP-1 maturation triggered by the contact allergen 1-fluoro-2,4-dinitrobenzene. Toxicol Res (Camb) 2016; 5:1512-1521. [PMID: 30090452 PMCID: PMC6060794 DOI: 10.1039/c6tx00240d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/03/2016] [Indexed: 12/20/2022] Open
Abstract
Dendritic cells' (DC) activation is considered a key event in the adverse outcome pathway for skin sensitization elicited by covalent binding of chemicals to proteins. The mechanisms underlying DC activation by contact sensitizers are not completely understood. However, several "danger signals" are pointed as relevant effectors. Among these extra-cellular early danger signals, purines may be crucial for the development of xenoinflammation and several reports indicate their involvement in contact allergic reactions. In the present work we used the DC-surrogate monocytic cell line THP-1, cultured alone or co-cultured with the human keratinocyte cell line HaCaT, to explore the contribution of extracellular adenine nucleotides to THP-1 maturation triggered by the extreme contact sensitizer, 1-fluoro-2,4-dinitrobenzene (DNFB). We found that THP-1 maturation induced by DNFB is impaired after purinergic signaling inhibition, and that the transcription of the purinergic metabotropic receptors P2Y2 and P2Y11 is modulated by the sensitizer. We also detected that THP-1 cells only partially hydrolyse extracellular adenosine triphosphate, leading to accumulation of the mono-phosphate derivative, AMP. We detected different and non-overlapping activation patterns of mitogen activated protein kinases by DNFB and extracellular nucleotides. Overall, our results indicate that THP-1 maturation induced by DNFB is strongly modulated by extracellular adenine nucleotides through metabotropic purinergic receptors. This knowledge unveils a molecular toxicity pathway evoked by sensitizers and involved in THP-1 maturation, a DC-surrogate cell line thoroughly used in in vitro tests for the identification of skin allergens.
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Affiliation(s)
- J D Martins
- Faculty of Pharmacy University of Coimbra , 3000-548 Coimbra , Portugal . ; ; ; Tel: +351 239 480 209
- CNC - Center for Neuroscience and Cell Biology , University of Coimbra , 3004-517 Coimbra , Portugal
| | - A Silva
- CNC - Center for Neuroscience and Cell Biology , University of Coimbra , 3004-517 Coimbra , Portugal
| | - I Ferreira
- CNC - Center for Neuroscience and Cell Biology , University of Coimbra , 3004-517 Coimbra , Portugal
| | - M Gonçalo
- Department of Dermatology , University Hospital and Faculty of Medicine , University of Coimbra , 3000-075 Coimbra , Portugal
| | - J B A Custódio
- Faculty of Pharmacy University of Coimbra , 3000-548 Coimbra , Portugal . ; ; ; Tel: +351 239 480 209
- CNC - Center for Neuroscience and Cell Biology , University of Coimbra , 3004-517 Coimbra , Portugal
| | - M C Lopes
- Faculty of Pharmacy University of Coimbra , 3000-548 Coimbra , Portugal . ; ; ; Tel: +351 239 480 209
- CNC - Center for Neuroscience and Cell Biology , University of Coimbra , 3004-517 Coimbra , Portugal
| | - M R M Domingues
- Department of Chemistry , Mass Spectrometry Center , QOPNA , University of Aveiro , Campus Universitário de Santiago , 3810-193 Aveiro , Portugal
| | - B M Neves
- Faculty of Pharmacy University of Coimbra , 3000-548 Coimbra , Portugal . ; ; ; Tel: +351 239 480 209
- CNC - Center for Neuroscience and Cell Biology , University of Coimbra , 3004-517 Coimbra , Portugal
- Department of Chemistry , Mass Spectrometry Center , QOPNA , University of Aveiro , Campus Universitário de Santiago , 3810-193 Aveiro , Portugal
| | - M T Cruz
- Faculty of Pharmacy University of Coimbra , 3000-548 Coimbra , Portugal . ; ; ; Tel: +351 239 480 209
- CNC - Center for Neuroscience and Cell Biology , University of Coimbra , 3004-517 Coimbra , Portugal
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Inhibition of P2X Receptors Protects Human Monocytes against Damage by Leukotoxin from Aggregatibacter actinomycetemcomitans and α-Hemolysin from Escherichia coli. Infect Immun 2016; 84:3114-3130. [PMID: 27528275 DOI: 10.1128/iai.00674-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 01/14/2023] Open
Abstract
α-Hemolysin (HlyA) from Escherichia coli and leukotoxin A (LtxA) from Aggregatibacter actinomycetemcomitans are important virulence factors in ascending urinary tract infections and aggressive periodontitis, respectively. The extracellular signaling molecule ATP is released immediately after insertion of the toxins into plasma membranes and, via P2X receptors, is essential for the erythrocyte damage inflicted by these toxins. Moreover, ATP signaling is required for the ensuing recognition and phagocytosis of damaged erythrocytes by the monocytic cell line THP-1. Here, we investigate how these toxins affect THP-1 monocyte function. We demonstrate that both toxins trigger early ATP release and a following increase in the intracellular Ca2+ concentration ([Ca2+]i) in THP-1 monocytes. The HlyA- and LtxA-induced [Ca2+]i response is diminished by the P2 receptor antagonist in a pattern that fits the functional P2 receptor expression in these cells. Both toxins are capable of lysing THP-1 cells, with LtxA being more aggressive. Either desensitization or blockage of P2X1, P2X4, or P2X7 receptors markedly reduces toxin-induced cytolysis. This pattern is paralleled in freshly isolated human monocytes from healthy volunteers. Interestingly, only a minor fraction of the toxin-damaged THP-1 monocytes eventually lyse. P2X7 receptor inhibition generally prevents cell damage, except from a distinct cell shrinkage that prevails in response to the toxins. Moreover, we find that preexposure to HlyA preserves the capacity of THP-1 monocytes to phagocytose damaged erythrocytes and may induce readiness to discriminate between damaged and healthy erythrocytes. These findings suggest a new pharmacological target for protecting monocytes during exposure to pore-forming cytolysins during infection or injury.
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Ribeiro-Filho AC, Buri MV, Barros CC, Dreyfuss JL, Nader HB, Justo GZ, Craveiro RB, Pesquero JB, Miranda A, Ferreira AT, Paredes-Gamero EJ. Functional and molecular evidence for heteromeric association of P2Y1 receptor with P2Y2 and P2Y4 receptors in mouse granulocytes. BMC Pharmacol Toxicol 2016; 17:29. [PMID: 27384918 PMCID: PMC4936188 DOI: 10.1186/s40360-016-0072-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 06/24/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND All hematopoietic cells express P2 receptors, however pharmacological characteristics such as expression and affinity in granulocytes are unknown. METHODS Pharmacological characteristics of P2 receptors were evaluated by Ca(2+) measurements using Fura-2 fluorophore. P2 receptors expression were analyzed by flow cytometry and RT-PCR. P2 interaction were shown by coimmunoprecipitation, western blotting and FRET. RESULTS Granulocytes were responsive to P2Y agonists, whereas P2X agonists were ineffective. Ca(2+) increase, elicited by ADP and UTP was dependent on intracellular stocks and sensitive to G-coupled receptor inhibition. Moreover, MRS2179, a specific antagonist of the P2Y1 receptor, abolished ADP response. Interestingly, ADP and UTP exhibited full heterologous desensitization, suggesting that these agonists interact with the same receptor. The heteromeric association between P2Y1 receptor and the P2Y2 and P2Y4 receptors was shown by immunoprecipitation and FRET analysis. CONCLUSION Clear evidence of heteromeric association of P2Y receptors was found during the evaluation of P2 receptors present in mice granulocytes, which could impact in the classical pharmacology of P2Y receptors in granulocytes.
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Affiliation(s)
- Antonio Carlos Ribeiro-Filho
- Centro Interdisciplinar de Investigação Bioquı́mica, Universidade de Mogi das Cruzes, Av. Dr Cândido Xavier de Almeida Souza, 200, Mogi das Cruzes, São Paulo, Brazil
| | - Marcus Vinicius Buri
- Departamento de Bioquímica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 9° andar - Prédio de Pesquisa II, R. Três de Maio 100, São Paulo, São Paulo, Brazil
| | - Carlos Castilho Barros
- Departamento de Nutrição, Universidade Federal de Pelotas, R. Gomes Carneiro, n°1, 96010-610, Pelotas, Rio Grande do Sul, Brazil
| | - Juliana Luporini Dreyfuss
- Departamento de Bioquímica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 9° andar - Prédio de Pesquisa II, R. Três de Maio 100, São Paulo, São Paulo, Brazil
| | - Helena Bonciani Nader
- Departamento de Bioquímica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 9° andar - Prédio de Pesquisa II, R. Três de Maio 100, São Paulo, São Paulo, Brazil
| | - Giselle Zenker Justo
- Departamento de Bioquímica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 9° andar - Prédio de Pesquisa II, R. Três de Maio 100, São Paulo, São Paulo, Brazil
| | - Rogério Bastos Craveiro
- Departamento de Biofísica, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, São Paulo, Brazil
| | - João Bosco Pesquero
- Departamento de Biofísica, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, São Paulo, Brazil
| | - Antonio Miranda
- Departamento de Biofísica, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, São Paulo, Brazil
| | - Alice Teixeira Ferreira
- Departamento de Biofísica, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, São Paulo, Brazil
| | - Edgar Julian Paredes-Gamero
- Centro Interdisciplinar de Investigação Bioquı́mica, Universidade de Mogi das Cruzes, Av. Dr Cândido Xavier de Almeida Souza, 200, Mogi das Cruzes, São Paulo, Brazil. .,Departamento de Bioquímica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 669 - 9° andar - Prédio de Pesquisa II, R. Três de Maio 100, São Paulo, São Paulo, Brazil.
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Katsnelson MA, Rucker LG, Russo HM, Dubyak GR. K+ efflux agonists induce NLRP3 inflammasome activation independently of Ca2+ signaling. THE JOURNAL OF IMMUNOLOGY 2015; 194:3937-52. [PMID: 25762778 DOI: 10.4049/jimmunol.1402658] [Citation(s) in RCA: 216] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 02/07/2015] [Indexed: 12/22/2022]
Abstract
Perturbation of intracellular ion homeostasis is a major cellular stress signal for activation of NLRP3 inflammasome signaling that results in caspase-1-mediated production of IL-1β and pyroptosis. However, the relative contributions of decreased cytosolic K(+) concentration versus increased cytosolic Ca(2+) concentration ([Ca(2+)]) remain disputed and incompletely defined. We investigated roles for elevated cytosolic [Ca(2+)] in NLRP3 activation and downstream inflammasome signaling responses in primary murine dendritic cells and macrophages in response to two canonical NLRP3 agonists (ATP and nigericin) that facilitate primary K(+) efflux by mechanistically distinct pathways or the lysosome-destabilizing agonist Leu-Leu-O-methyl ester. The study provides three major findings relevant to this unresolved area of NLRP3 regulation. First, increased cytosolic [Ca(2+)] was neither a necessary nor sufficient signal for the NLRP3 inflammasome cascade during activation by endogenous ATP-gated P2X7 receptor channels, the exogenous bacterial ionophore nigericin, or the lysosomotropic agent Leu-Leu-O-methyl ester. Second, agonists for three Ca(2+)-mobilizing G protein-coupled receptors (formyl peptide receptor, P2Y2 purinergic receptor, and calcium-sensing receptor) expressed in murine dendritic cells were ineffective as activators of rapidly induced NLRP3 signaling when directly compared with the K(+) efflux agonists. Third, the intracellular Ca(2+) buffer, BAPTA, and the channel blocker, 2-aminoethoxydiphenyl borate, widely used reagents for disruption of Ca(2+)-dependent signaling pathways, strongly suppressed nigericin-induced NLRP3 inflammasome signaling via mechanisms dissociated from their canonical or expected effects on Ca(2+) homeostasis. The results indicate that the ability of K(+) efflux agonists to activate NLRP3 inflammasome signaling can be dissociated from changes in cytosolic [Ca(2+)] as a necessary or sufficient signal.
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Affiliation(s)
| | - L Graham Rucker
- The Ohio State University College of Medicine, Columbus, OH 43210; and
| | - Hana M Russo
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106
| | - George R Dubyak
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
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Abousamra NK, Salah El-Din M, Hamza Elzahaf E, Esmael ME. Ectonucleoside triphosphate diphosphohydrolase-1 (E-NTPDase1/CD39) as a new prognostic marker in chronic lymphocytic leukemia. Leuk Lymphoma 2014; 56:113-9. [PMID: 24684231 DOI: 10.3109/10428194.2014.907893] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Numerous prognostic markers were introduced to screen for patients with B-cell chronic lymphocytic leukemia (B-CLL) likely to have a progressive course, bearing the potential to facilitate risk-adapted treatment strategies. Extracellular adenosine triphosphate (ATP) functions as a "natural adjuvant" that boosts immune response in the tumor microenvironment. Ectonucleoside triphosphate diphosphohydrolase-1 (CD39/ENTPD1) is the ectonucleotidase that catalyzes the hydrolysis of ATP. The present study was conducted to analyze CD39 expression in T cells and B-CLL cells to evaluate its impact on the clinical course of patients with B-CLL and correlate its levels with well-established risk factors. T-cell CD39 expression was significantly increased in patients' peripheral blood compared to healthy controls. The higher levels were associated with advanced stages of disease and negatively interacted with time to first treatment. Overall, our data indicate that T-cell CD39 expression may identify subsets of patients with B-CLL with an unfavorable clinical outcome. Moreover, it can be incorporated into prognostic schema to improve the prediction of CLL disease progression.
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Affiliation(s)
- Nashwa Khairat Abousamra
- Department of Clinical Pathology, Hematology Unit, Faculty of Medicine, Mansoura University , Egypt
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Changes in purine levels associated with cellular brain injury in gerbils experimentally infected with Neospora caninum. Res Vet Sci 2014; 96:507-11. [PMID: 24702899 DOI: 10.1016/j.rvsc.2014.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 02/10/2014] [Accepted: 03/01/2014] [Indexed: 01/04/2023]
Abstract
The present study was carried out in order to assess the possible alterations in purine levels of brain, associated neuronal lesions in gerbils experimentally infected with Neospora caninum. For that, gerbils (Meriones unguiculatus) were inoculated with Nc-1 strain of N. caninum, composing two different experiments: Experiment I (EI) and experiment II (EII), where purine levels were measured along with the histopathologic study, on days 7 (EI), 15 and 30 (EII), post-infection (PI). As a result, it was possible to observe that the purine levels (ATP, ADP, AMP, adenosine, inosine and xanthine) in brain in EI are significantly reduced (p < 0.05), while in EII we faced a different pattern, since in the majority the purine levels were significantly increased (p < 0.05) on days 15 (ATP, AMP, adenosine, hypoxanthine and xanthine) and 30 PI (ATP, ADP, AMP, adenosine, and uric acid). Results of brain histopathology did not show histological lesion in animals of EI; however, in gerbils of EII it was possible to verify that the alterations (lesions) were more pronounced in gerbils evaluated on day 30 PI when compared to day 15 PI. Therefore, it was possible to conclude that the purine levels in brain were altered in both experiments, concomitant with the histopathological injuries observed in EII.
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Vergani A, Tezza S, Fotino C, Visner G, Pileggi A, Chandraker A, Fiorina P. The purinergic system in allotransplantation. Am J Transplant 2014; 14:507-14. [PMID: 24433446 DOI: 10.1111/ajt.12567] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/31/2013] [Accepted: 10/31/2013] [Indexed: 01/25/2023]
Abstract
The purine nucleotide adenosine triphosphate (ATP) is a universal source of energy for any intracellular reaction. Under specific physiological or pathological conditions, ATP can be released into extracellular spaces, where it binds and activates the purinergic receptors system (i.e. P2X, P2Y and P1 receptors). Extracellular ATP (eATP) binds to P2X or P2Y receptors in immune cells, where it mediates proliferation, chemotaxis, cytokine release, antigen presentation and cytotoxicity. eATP is then hydrolyzed by ectonucleotidases into adenosine diphosphate (ADP), which activates P2Y receptors. Ectonucleotidases also hydrolyze ADP to adenosine monophosphate and adenosine, which binds P1 receptors. In contrast to P2X and P2Y receptors, P1 receptors exert mainly an inhibitory effect on the immune response. In transplantation, a prominent role has been demonstrated for the eATP/P2X7R axis; the targeting of this pathway in fact is associated with long-term graft function and reduced graft versus host disease severity in murine models. Novel P2X receptor inhibitors are available for clinical use and are under assessment as immunomodulatory agents. In this review, we will focus on the relevance of the purinergic system and on the potential benefits of targeting this system in allograft rejection and tolerance.
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Affiliation(s)
- A Vergani
- Nephrology Division, Boston Children's Hospital, Harvard Medical School, Boston, MA; Department of Medicine, San Raffaele Scientific Institute, Milan, Italy
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Manque PA, Woehlbier U, Lara AM, Tenjo F, Alves JM, Buck GA. Identification and characterization of a novel calcium-activated apyrase from Cryptosporidium parasites and its potential role in pathogenesis. PLoS One 2012; 7:e31030. [PMID: 22363541 PMCID: PMC3280346 DOI: 10.1371/journal.pone.0031030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/30/2011] [Indexed: 01/20/2023] Open
Abstract
Herein, we report the biochemical and functional characterization of a novel Ca2+-activated nucleoside diphosphatase (apyrase), CApy, of the intracellular gut pathogen Cryptosporidium. The purified recombinant CApy protein displayed activity, substrate specificity and calcium dependency strikingly similar to the previously described human apyrase, SCAN-1 (soluble calcium-activated nucleotidase 1). CApy was found to be expressed in both Cryptosporidium parvum oocysts and sporozoites, and displayed a polar localization in the latter, suggesting a possible co-localization with the apical complex of the parasite. In vitro binding experiments revealed that CApy interacts with the host cell in a dose-dependent fashion, implying the presence of an interacting partner on the surface of the host cell. Antibodies directed against CApy block Cryptosporidium parvum sporozoite invasion of HCT-8 cells, suggesting that CApy may play an active role during the early stages of parasite invasion. Sequence analyses revealed that the capy gene shares a high degree of homology with apyrases identified in other organisms, including parasites, insects and humans. Phylogenetic analysis argues that the capy gene is most likely an ancestral feature that has been lost from most apicomplexan genomes except Cryptosporidium, Neospora and Toxoplasma.
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Affiliation(s)
- Patricio A. Manque
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Ute Woehlbier
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Ana M. Lara
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Fernando Tenjo
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - João M. Alves
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Gregory A. Buck
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Jantaratnotai N, McGeer PL, McLarnon JG. Mechanisms of Mg2+ inhibition of BzATP-dependent Ca2+ responses in THP-1 monocytes. Brain Res 2012; 1442:1-8. [PMID: 22297175 DOI: 10.1016/j.brainres.2012.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 12/14/2011] [Accepted: 01/04/2012] [Indexed: 12/31/2022]
Abstract
We have recently reported effects of Mg2+ to confer neuroprotection against toxicity of purinergic stimulated microglia and THP-1 monocytes. To examine mechanisms underlying neuroprotection, we have studied Mg2+ modulation of transient changes in intracellular Ca2+ ([Ca2+]i) in THP-1 cells induced by P2X7R agonist 2',3'-[benzoyl-4-benzoyl]-ATP (BzATP). Application of BzATP caused a rapid transient increase in [Ca2+]i followed by a prolonged component. The time course of the secondary slower phase was significantly reduced with Ca2+-free extracellular solution, with treatment of THP-1 cells by the P2X7R antagonist, oxATP or with exposure of cells to the store-operated channel (SOC) inhibitor, SKF96365. These results suggest that Ca2+ influx, mediated by both the P2X7R or by SOC, contribute to the slow component of [Ca2+]i. Treatment of THP-1 cells with 10 mMMg2+ was highly effective in reducing the time course of BzATP-induced Ca2+ decay; unlike the other modulatory protocols, Mg2+ markedly inhibited the amplitudes of slow and rapid components. In addition, acute application of Mg2+ during BzATP-induced responses elicited in the presence of either oxATP or SKF96365 to block respective P2X7R and SOC contributions, rapidly attenuated [Ca2+]i to baseline levels. Priming of cells with the inflammatory stimulus LPS/IFN-γ markedly enhanced the slower, but not rapid, phase of BzATP-induced [Ca2+]i with application of 10 mMMg2+ inhibiting both components of response. A model is proposed to account for BzATP stimulation of both ionotropic P2XR and metabotropic P2YR which provides a mechanistic basis for elevated Mg2+ anti-inflammatory and neuroprotective actions in inflamed brain.
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Affiliation(s)
- Nattinee Jantaratnotai
- Department of Anesthesiology, Pharmacology and Therapeutics, 2176 Health Sciences Mall, University of British Columbia, Vancouver, BC, Canada
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Fontana M, Rezer J, Coradini K, Leal D, Beck R. Improved efficacy in the treatment of contact dermatitis in rats by a dermatological nanomedicine containing clobetasol propionate. Eur J Pharm Biopharm 2011; 79:241-9. [DOI: 10.1016/j.ejpb.2011.05.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 05/02/2011] [Accepted: 05/04/2011] [Indexed: 11/24/2022]
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Hopfe M, Dahlmanns T, Henrich B. In Mycoplasma hominis the OppA-mediated cytoadhesion depends on its ATPase activity. BMC Microbiol 2011; 11:185. [PMID: 21854595 PMCID: PMC3179953 DOI: 10.1186/1471-2180-11-185] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 08/19/2011] [Indexed: 12/20/2022] Open
Abstract
Background In Mycoplasma hominis, a facultative human pathogen of the human genital tract, OppA, the substrate-binding domain of the oligopeptide permease, is a multifunctional protein involved in nutrition uptake, cytoadhesion and hydrolysis of extracellular ATP. Results To map the function-related protein regions the ATPase activity and adhesive behavior of OppA mutants were analyzed. Mutations of the Walker BA motifs resulted in an inhibition of up to 8% of the OppA ATPase activity, whereas deletion of the N-terminal CS1 or the CS2 region, structural motifs that are conserved in bacterial OppA proteins, reduced ATPase activity to 60% and deletion of CS3, the third conserved region adjacent to the Walker B motif led to a reduction to 42% ATPase activity. Interestingly, adhesion of the OppA mutants to immobilized HeLa cells demonstrated that two distal regions are mainly involved in adherence of OppA: the CS1 region, deletion of which led to 35% of the cytoadhesion, and the Walker BA with the adjacent upstream region CS3, deletion of which led to 25% of the cytoadhesion. The influence of the ATPase activity on the adherence of M. hominis to HeLa cells was confirmed by the use of ATPase inhibitors which reduced mycoplasmal cytoadhesion to 50%. Conclusions These findings suggest that the OppA-mediated cytoadherence of Mycoplasma hominis depends on both, the topology of the neighbouring CS1 and ATPase domain regions and the functionality of the ecto-ATPase activity in addition.
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Affiliation(s)
- Miriam Hopfe
- Institute of Medical Microbiology and Hospital Hygiene, Heinrich-Heine-University Duesseldorf, Moorenstrasse 5, 40225 Duesseldorf, Germany
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Marques-da-Silva C, Chaves MM, Chaves SP, Figliuolo VR, Meyer-Fernandes JR, Corte-Real S, Lameu C, Ulrich H, Ojcius DM, Rossi-Bergmann B, Coutinho-Silva R. Infection with Leishmania amazonensis upregulates purinergic receptor expression and induces host-cell susceptibility to UTP-mediated apoptosis. Cell Microbiol 2011; 13:1410-28. [PMID: 21740498 DOI: 10.1111/j.1462-5822.2011.01630.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nucleotides are released into the extracellular milieu from infected cells and cells at inflammatory sites. The extracellular nucleotides bind to specific purinergic (P2) receptors and thereby induce a variety of cellular responses including anti-parasitic effects. Here we investigated whether extracellular nucleotides affect leishmanial infection in macrophages, and found that UTP reduces strongly the parasite load in peritoneal macrophages. Ultrastructural analysis of infected cells revealed that UTP induced morphological damage in the intracellular parasites. Uridine nucleotides also induced dose-dependent apoptosis of macrophages and production of ROI and RNI only in infected macrophages. The intracellular calcium measurements of infected cells showed that the response to UTP, but not UDP, increased the sensitivity and amplitude of cytosolic Ca(2+) changes. Infection of macrophages with Leishmania upregulated the expression of P2Y(2) and P2Y(4) receptor mRNA. The data suggest indirectly that Leishmania amazonensis infection induces modulation and heteromerization of P2Y receptors on macrophages. Thus UTP modulates the host response against L. amazonensis infection. UTP and UTP homologues should therefore be considered as novel components of therapeutic strategies against cutaneous leishmaniasis.
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Affiliation(s)
- Camila Marques-da-Silva
- Laboratory of Immunophysiology, Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro RJ, 21941-902, Brazil
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15
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Grazia Perrone M, Scilimati A. β(3)-Adrenoceptor agonists and (antagonists as) inverse agonists history, perspective, constitutive activity, and stereospecific binding. Methods Enzymol 2011; 484:197-230. [PMID: 21036234 DOI: 10.1016/b978-0-12-381298-8.00011-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
β(3)-Adrenergic receptor (β(3)-AR) is expressed in several tissues and is considered a drug target for the treatment of several pathologies such as obesity, type 2 diabetes, cachexia, metabolic syndrome, heart failure, anxiety and depressive disorders, preterm labor, overactive bladder, control colon motility, and of coadjuvants in colon cancer therapy. It is a seven-transmembrane domain (7TD) G-protein coupled receptor and is usually coupled to a Gs-protein (Gi-protein in very few cases), and its stimulation increases the production of cAMP. A lot of β(3)-AR agonists have been uncovered and extensively characterized. Conversely, very little is known about β(3)-AR inverse agonists that would suppress the agonist-independent activity (constitutive activity) of the receptor by stabilizing it in its inactive state. This chapter attempts to outline (a) the importance of the β(3)-AR as a therapeutic target through the disquisition of its role in human health (physiology) and disease (pathology); (b) the description of β(3)-AR structure [amino acid sequence and 7TD organization]; (c) the medicinal chemistry of β(3)-AR: 7TD amino acid-ligand specific interactions, β-adrenoreceptor subtype selectivity, stereospecific interactions and biological activity relationships, inverse agonism and blockage of β(3)-adrenoceptor constitutive activity; and (d) β(3)-AR inverse agonists. The detailed procedure to prepare and assess the biological activity/selectivity of the more potent and selective β(3)-AR inverse agonists (SP-1e and SP-1g) up to now known is also described.
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Cutler AJ, Limbani V, Girdlestone J, Navarrete CV. Umbilical cord-derived mesenchymal stromal cells modulate monocyte function to suppress T cell proliferation. THE JOURNAL OF IMMUNOLOGY 2010; 185:6617-23. [PMID: 20980628 DOI: 10.4049/jimmunol.1002239] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mesenchymal stromal cells (MSCs) may be derived from a variety of tissues, with human umbilical cord (UC) providing an abundant and noninvasive source. Human UC-MSCs share similar in vitro immunosuppressive properties as MSCs obtained from bone marrow and cord blood. However, the mechanisms and cellular interactions used by MSCs to control immune responses remain to be fully elucidated. In this paper, we report that suppression of mitogen-induced T cell proliferation by human UC-, bone marrow-, and cord blood-MSCs required monocytes. Removal of monocytes but not B cells from human adult PBMCs (PBMNCs) reduced the immunosuppressive effects of MSCs on T cell proliferation. There was rapid modulation of a number of cell surface molecules on monocytes when PBMCs or alloantigen-activated PBMNCs were cultured with UC-MSCs. Indomethacin treatment significantly inhibited the ability of UC-MSCs to suppress T cell proliferation, indicating an important role for PGE(2). Monocytes purified from UC-MSC coculture had significantly reduced accessory cell and allostimulatory function when tested in subsequent T cell proliferation assays, an effect mediated in part by UC-MSC PGE(2) production and enhanced by PBMNC alloactivation. Therefore, we identify monocytes as an essential intermediary through which UC-MSCs mediate their suppressive effects on T cell proliferation.
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Affiliation(s)
- Antony J Cutler
- Histocompatibility and Immunogenetics Research Group, National Health Service Blood and Transplant, London, United Kingdom
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Gadeock S, Tran JNSN, Georgiou JG, Jalilian I, Taylor RM, Wiley JS, Sluyter R. TGF-β1 prevents up-regulation of the P2X7 receptor by IFN-γ and LPS in leukemic THP-1 monocytes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:2058-66. [PMID: 20670615 DOI: 10.1016/j.bbamem.2010.07.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 07/20/2010] [Accepted: 07/21/2010] [Indexed: 11/15/2022]
Abstract
The P2X7 receptor is an extracellular ATP-gated cation channel critical in inflammation and immunity, and can be up-regulated by IFN-γ and LPS. This study aimed to examine the effect of TGF-β1 on the up-regulation of P2X7 function and expression in leukemic THP-1 monocytes differentiated with IFN-γ and LPS. Cell-surface molecules including P2X7 were examined by immunofluorescence staining. Total P2X7 protein and mRNA was assessed by immunoblotting and RT-PCR respectively. P2X7 function was evaluated by ATP-induced cation dye uptake measurements. Cell-surface P2X7 was present on THP-1 cells differentiated for 3days with IFN-γ and LPS but not on undifferentiated THP-1 cells. ATP induced ethidium(+) uptake into differentiated but not undifferentiated THP-1 cells, and the P2X7 antagonist, KN-62, impaired ATP-induced ethidium(+) uptake. Co-incubation of cells with TGF-β1 plus IFN-γ and LPS prevented the up-regulation of P2X7 expression and ATP-induced ethidium(+) uptake in a concentration-dependent fashion with a maximum effect at 5ng/ml and with an IC(50) of ~0.4ng/ml. Moreover, ATP-induced YO-PRO-1(2+) uptake and IL-1β release were abrogated in cells co-incubated with TGF-β1. TGF-β1 also abrogated the amount of total P2X7 protein and mRNA induced by IFN-γ and LPS. Finally, TGF-β1 prevented the up-regulation of cell-surface CD86, but not CD14 and MHC class II, by IFN-γ and LPS. These results indicate that TGF-β1 prevents the up-regulation of P2X7 function and expression by IFN-γ and LPS in THP-1 monocytes. This suggests that TGF-β1 may limit P2X7-mediated processes in inflammation and immunity.
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Affiliation(s)
- Safina Gadeock
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
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18
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Enzymes that hydrolyze adenine nucleotides in lymphocytes and platelets of immunosuppressed rats. Biomed Pharmacother 2010; 64:437-40. [PMID: 20359849 DOI: 10.1016/j.biopha.2010.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 01/25/2010] [Indexed: 11/21/2022] Open
Abstract
NTPDase (EC 3.6.1.5) is an enzyme that hydrolyzes extracellular nucleoside tri-and/ or diphosphates to form ATP, which can serve as a substrate for ecto-5'- nucleotidase (EC 3.1.3.5), releasing adenosine, an inhibitor of platelet aggregation and an immunosuppressant agent. In this study, the activity of enzymes that hydrolyze adenine nucleotides was investigated in lymphocytes and platelets of immunosuppressed rats. NTPDase and ecto-5'-nucleotidase activities were determined by colorimetric assay with quantification of the inorganic phosphate released. A significant increase in NTPDase activity was observed in lymphocytes (about 30% in ATP hydrolysis and 80% in ADP hydrolysis, at p<0.05 and p<0.01, respectively). In platelets, there was a significant increase in 5'-nucleotidase activity in immunosuppressed rats (p<0.01) when compared with controls. These results suggest that the hydrolysis of adenine nucleotides is modified in the immunosuppressed state, possibly to compensate for alterations that occur and to avoid the adverse effects of therapy.
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Hopfe M, Henrich B. OppA, the ecto-ATPase of Mycoplasma hominis induces ATP release and cell death in HeLa cells. BMC Microbiol 2008; 8:55. [PMID: 18394151 PMCID: PMC2323007 DOI: 10.1186/1471-2180-8-55] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Accepted: 04/04/2008] [Indexed: 12/21/2022] Open
Abstract
Background In the facultative human pathogen Mycoplasma hominis, which belongs to the cell wall-less Mollicutes, the surface-localised substrate-binding domain OppA of the oligopeptide permease was characterised as the main ecto-ATPase. Results With the idea that extra-cellular ATP could only be provided by the infected host cells we analysed the ATP release of HeLa cells after incubation with different preparations of Mycoplasma hominis: intact bacterial cells, the membrane fraction with or without OppA, recombinant OppA as well as an ATPase-deficient OppA mutant. Release of ATP into the supernatant of the HeLa cells was primarily determined in all samples lacking ecto-ATPase activity of OppA. In the presence of the ATPase inhibitor DIDS the amount of ATP in the OppA-containing samples increased. This increase was maximal after incubation with fractions containing OppA protein indicating that OppA is involved in ATP release and subsequent hydrolysis. Real-time PCR analyses revealed that the proliferation of HeLa cells is reduced after infection with M. hominis and flow cytometry experiments established that OppA induces greater apoptosis than necrosis of HeLa cells whereas the preservation of ecto-ATPase activity of OppA induces apoptosis. Conclusion The OppA induced ATP-release and -hydrolysis induced cell death of M. hominis infected HeLa cells was predominantly due to apoptosis rather than necrosis. Future work will elucidate whether the induction of apoptosis is indispensable for survival of these non-invasive pathogen.
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Affiliation(s)
- Miriam Hopfe
- Institute of Medical Microbiology and Center for Biological Medical Research, Heinrich-Heine-University, Moorenstrasse 5, 40225 Duesseldorf, Germany.
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Peres-Sampaio CE, de Almeida-Amaral EE, Giarola NLL, Meyer-Fernandes JR. Leishmania amazonensis: effects of heat shock on ecto-ATPase activity. Exp Parasitol 2008; 119:135-43. [PMID: 18295760 DOI: 10.1016/j.exppara.2008.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 11/30/2007] [Accepted: 01/11/2008] [Indexed: 10/22/2022]
Abstract
In this work we demonstrated that promastigotes of Leishmania amazonensis exhibit an Mg-dependent ecto-ATPase activity, which is stimulated by heat shock. The Mg-dependent ATPase activity of cells grown at 22 and 28 degrees C was 41.0+/-5.2 nmol Pi/h x 10(7)cells and 184.2+/-21.0 nmol Pi/h x 10(7)cells, respectively. When both promastigotes were pre-incubated at 37 degrees C for 2h, the ATPase activity of cells grown at 22 degrees C was increased to 136.4+/-10.6 nmol Pi/h x 10(7) whereas that the ATPase activity of cells grown at 28 degrees C was not modified by the heat shock (189.8+/-10.3 nmol Pi/h x 10(7)cells). It was observed that Km of the enzyme from cells grown at 22 degrees C (Km=980.2+/-88.6 microM) was the same to the enzyme from cells grown at 28 degrees C (Km=901.4+/-91.9 microM). In addition, DIDS (4,4'-diisothiocyanatostilbene 2,2'-disulfonic acid) and suramin, two inhibitors of ecto-ATPases, also inhibited similarly the ATPase activities from promastigotes grown at 22 and 28 degrees C. We also observed that cells grown at 22 degrees C exhibit the same ecto-phosphatase and ecto 3'- and 5'-nucleotidase activities than cells grown at 28 degrees C. Interestingly, cycloheximide, an inhibitor of protein synthesis, suppressed the heat-shock effect on ecto-ATPase activity of cells grown at 22 degrees C were exposed at 37 degrees C for 2h. A comparison between the stimulation of the Mg-dependent ecto-ATPase activity of virulent and avirulent promastigotes by the heat shock showed that avirulent promastigotes had a higher stimulation than virulent promastigotes after heat stress.
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Affiliation(s)
- Carlos Eduardo Peres-Sampaio
- Faculdade de Enfermagem-FENF, Centro Biomédico, Universidade do Estado do Rio de Janeiro-UERJ, Av. 28 de setembro 87, Vila Isabel, 20551-030, Rio de Janeiro, RJ, Brazil
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Pulte ED, Broekman MJ, Olson KE, Drosopoulos JHF, Kizer JR, Islam N, Marcus AJ. CD39/NTPDase-1 activity and expression in normal leukocytes. Thromb Res 2007; 121:309-17. [PMID: 17555802 PMCID: PMC2255570 DOI: 10.1016/j.thromres.2007.04.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 04/17/2007] [Accepted: 04/24/2007] [Indexed: 10/23/2022]
Abstract
INTRODUCTION CD39/NTPDase-1 is a cell surface enzyme expressed on leukocytes and endothelial cells that metabolizes ATP to ADP and AMP. CD39 is expressed on numerous different types of normal leukocytes, but details of its expression have not been determined previously. METHODS We examined CD39 expression and activity in leukocytes isolated from healthy volunteers. Expression of CD39 on leukocytes was measured by FACS and activity of CD39 in lymphocytes and neutrophils was determined by an enzymatic radio-TLC assay. RESULTS We established that CD39 is expressed on neutrophils, lymphocytes, and monocytes. The enzyme is found on >90% of monocytes, neutrophils, and B-lymphocytes, and 6% of T-lymphocytes and natural killer cells. Per cell density of expression varied, with the highest expression on monocytes and B-lymphocytes. ATPase and ADPase activities were highest on B-lymphocytes, lower on neutrophils, lowest on T-lymphocytes. The ratio of ADPase:ATPase activity was 1.8 for neutrophils and B-lymphocytes and 1.4 for T-lymphocytes. Hypertensive volunteers had lower levels of CD39 on their T-lymphocytes and NK cells. No correlation between age, gender, ethnic background, or cholesterol level and CD39 expression was observed. CONCLUSIONS We conclude that CD39 activity and expression are present to varying degrees on all leukocytes types examined. Differences between leukocyte types should be considered when examining CD39 in disease states.
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Affiliation(s)
- E Dianne Pulte
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010
- Medicine-Hematology/Oncology, Weill Medical College of Cornell University, New York, NY 10021
| | - M Johan Broekman
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010
- Medicine-Hematology/Oncology, Weill Medical College of Cornell University, New York, NY 10021
| | - Kim E Olson
- Medicine-Hematology/Oncology, Weill Medical College of Cornell University, New York, NY 10021
| | - Joan H F Drosopoulos
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010
- Medicine-Hematology/Oncology, Weill Medical College of Cornell University, New York, NY 10021
| | - Jorge R Kizer
- Medicine and Public Health, Weill Medical College of Cornell University, New York, NY 10021
| | - Naziba Islam
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010
- Medicine-Hematology/Oncology, Weill Medical College of Cornell University, New York, NY 10021
| | - Aaron J Marcus
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010
- Medicine-Hematology/Oncology, Weill Medical College of Cornell University, New York, NY 10021
- Pathology and Laboratory Medicine, Weill Medical College of Cornell University, New York, NY 10021
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Barat C, Martin G, Beaudoin AR, Sévigny J, Tremblay MJ. The nucleoside triphosphate diphosphohydrolase-1/CD39 is incorporated into human immunodeficiency type 1 particles, where it remains biologically active. J Mol Biol 2007; 371:269-82. [PMID: 17560607 PMCID: PMC5239664 DOI: 10.1016/j.jmb.2007.05.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 04/30/2007] [Accepted: 05/03/2007] [Indexed: 12/29/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) carries a variety of host proteins in addition to virus-encoded structural proteins, both in its envelope and inside the viral particle. Previous studies have reported that the HIV-1 life-cycle is affected by such virus-associated host cell surface proteins. The nucleoside triphosphate diphosphohydrolase-1 (NTPDase1), also known as CD39, is a plasma membrane-bound ectoenzyme that hydrolyzes extracellular ATP and ADP to AMP. It has been shown that CD39 inhibits platelet function, and is thus a critical thromboregulatory molecule. We demonstrate here that host-derived CD39 is acquired by both laboratory-adapted and clinical variants of HIV-1 produced in cellular reservoirs of the virus. Moreover, purified CD39-bearing virions, but not isogenic viruses lacking CD39, display strong ATPase and ADPase activities. It is of particular interest that virions bearing this cellular enzyme can inhibit ADP-induced platelet aggregation, an effect blocked by an NTPDase inhibitor. On the basis of published and the present data on the functionality of human cellular proteins embedded within HIV-1, it can be proposed that these proteins might contribute to some of the immunologic deficiencies seen in infected individuals.
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Affiliation(s)
- Corinne Barat
- Research Center in Infectious Diseases, CHUL Research Center, and Faculty of Medicine Laval University, Quebec Canada G1V 4G2
| | - Geneviève Martin
- Research Center in Infectious Diseases, CHUL Research Center, and Faculty of Medicine Laval University, Quebec Canada G1V 4G2
| | - Adrien R. Beaudoin
- Centre de Recherche en Rhumatologie et Immunologie CHUL Research Center and Faculty of Medicine Laval University, Quebec Canada G1V 4G2
| | - Jean Sévigny
- Research Center in Infectious Diseases, CHUL Research Center, and Faculty of Medicine Laval University, Quebec Canada G1V 4G2
| | - Michel J. Tremblay
- Research Center in Infectious Diseases, CHUL Research Center, and Faculty of Medicine Laval University, Quebec Canada G1V 4G2
- Corresponding author:
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Pulte D, Olson KE, Broekman MJ, Islam N, Ballard HS, Furman RR, Olson AE, Marcus AJ. CD39 activity correlates with stage and inhibits platelet reactivity in chronic lymphocytic leukemia. J Transl Med 2007; 5:23. [PMID: 17480228 PMCID: PMC1885243 DOI: 10.1186/1479-5876-5-23] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 05/04/2007] [Indexed: 01/10/2023] Open
Abstract
Background Chronic lymphocytic leukemia (CLL) is characterized by accumulation of mature appearing lymphocytes and is rarely complicated by thrombosis. One possible explanation for the paucity of thrombotic events in these patients may be the presence of the ecto-nucleotidase CD39/NTDPase-1 on the surface of the malignant cells in CLL. CD39 is the major promoter of platelet inhibition in vivo via its metabolism of ADP to AMP. We hypothesize that if CD39 is observed on CLL cells, then patients with CLL may be relatively protected against platelet aggregation and recruitment and that CD39 may have other effects on CLL, including modulation of the disease, via its metabolism of ATP. Methods Normal and malignant lymphocytes were isolated from whole blood from patients with CLL and healthy volunteers. Enzyme activity was measured via radio-TLC assay and expression via FACS. Semi-quantititative RT-PCR for CD39 splice variants and platelet function tests were performed on several samples. Results Functional assays demonstrated that ADPase and ATPase activities were much higher in CLL cells than in total lymphocytes from the normal population on a per cell basis (p-value < 0.00001). CD39 activity was elevated in stage 0–2 CLL compared to stage 3–4 (p < 0.01). FACS of lymphocytes demonstrated CD39 expression on > 90% of normal and malignant B-lymphocytes and ~8% of normal T-lymphocytes. RT-PCR showed increased full length CD39 and splice variant 1.5, but decreased variant 1.3 in CLL cells. Platelet function tests showed inhibition of platelet activation and recruitment to ADP by CLL cells. Conclusion CD39 is expressed and active on CLL cells. Enzyme activity is higher in earlier stages of CLL and decreased enzyme activity may be associated with worsening disease. These results suggest that CD39 may play a role in the pathogenesis of malignancy and protect CLL patients from thrombotic events.
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MESH Headings
- Adenosine Diphosphate/pharmacology
- Adult
- Aged
- Aged, 80 and over
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Apyrase/genetics
- Apyrase/metabolism
- B-Lymphocytes/metabolism
- B-Lymphocytes/pathology
- Chromatography, Thin Layer
- Female
- Flow Cytometry
- Gene Expression Regulation, Leukemic/drug effects
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/physiopathology
- Lymphocyte Subsets/metabolism
- Male
- Middle Aged
- Platelet Activation/drug effects
- Platelet Activation/physiology
- Platelet Aggregation/drug effects
- Reverse Transcriptase Polymerase Chain Reaction
- T-Lymphocytes/metabolism
- T-Lymphocytes/pathology
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Affiliation(s)
- Dianne Pulte
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
- Medicine-Hematology/Oncology, Weill Medical College Cornell University, New York, NY 10021, USA
| | - Kim E Olson
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
- Medicine-Hematology/Oncology, Weill Medical College Cornell University, New York, NY 10021, USA
| | - M Johan Broekman
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
- Medicine-Hematology/Oncology, Weill Medical College Cornell University, New York, NY 10021, USA
| | - Naziba Islam
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
- Medicine-Hematology/Oncology, Weill Medical College Cornell University, New York, NY 10021, USA
| | - Harold S Ballard
- Medical Service, VA NY Harbor Healtcare System, New York, NY 10010, USA
| | - Richard R Furman
- Medicine-Hematology/Oncology, Weill Medical College Cornell University, New York, NY 10021, USA
| | - Ashley E Olson
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
| | - Aaron J Marcus
- Research Service, Veterans Affairs New York Harbor Healthcare System, New York, NY 10010, USA
- Medicine-Hematology/Oncology, Weill Medical College Cornell University, New York, NY 10021, USA
- Medical Service, VA NY Harbor Healtcare System, New York, NY 10010, USA
- Pathology and Laboratory Medicine, Weill Medical College of Cornell University, New York, NY 10021, USA
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Kim JV, Dustin ML. Innate response to focal necrotic injury inside the blood-brain barrier. THE JOURNAL OF IMMUNOLOGY 2007; 177:5269-77. [PMID: 17015712 DOI: 10.4049/jimmunol.177.8.5269] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have studied the initial innate immune response to focal necrotic injury on different sides of the mouse blood-brain barrier by two-photon intravital microscopy. Transgenic mice in which the promoter of the myeloid isoform of lysozyme drives GFP were used to track granulocytes and monocytes. Necrotic injury in the meninges, but not the brain parenchyma, recruited GFP+ cells within minutes that fully surrounded the necrotic site within a day. Recently, it has been suggested that microglial cells and astrocytes cooperate to mount a distinct response to laser injury behind the blood-brain barrier. We followed the microglial response in heterozygous knockin mice in which GFP replaces CX3CR1 coding sequence. Prior to injury, microglial cell bodies were immobile over days, but moved to the laser injury site within 1 day. We followed astrocytes, which have been proposed to cooperate with microglial cells in response to focal injury, using transgenic mice in which glial fibrillary acidic protein promoter drives GFP expression. Before injury fine astrocyte processes permeate the parenchyma. Astrocytes polarized toward the injury in an ATP, connexin hemichannels, and intracellular Ca2+ -dependent process. The astrocytes network established a cytoplasmic Ca2+ gradient that preceded the microglial response. This is consistent with astrocyte-microglial collaboration to mount this innate response that excludes blood leukocytes.
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Affiliation(s)
- Jiyun V Kim
- Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine, Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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Lee DH, Park KS, Kong ID, Kim JW, Han BG. Expression of P2 receptors in human B cells and Epstein-Barr virus-transformed lymphoblastoid cell lines. BMC Immunol 2006; 7:22. [PMID: 16970829 PMCID: PMC1609185 DOI: 10.1186/1471-2172-7-22] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2006] [Accepted: 09/14/2006] [Indexed: 01/01/2023] Open
Abstract
Background Epstein-Barr virus (EBV) infection immortalizes primary B cells in vitro and generates lymphoblastoid cell lines (LCLs), which are used for several purposes in immunological and genetic studies. Purinergic receptors, consisting of P2X and P2Y, are activated by extracellular nucleotides in most tissues and exert various physiological effects. In B cells, especially EBV-induced LCLs, their expression and function have not been well studied. We investigated the expression of P2 receptors on primary human B cells and LCLs using the quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method for revealing the gene expression profile of the P2 receptor subtypes and their changes during transformation. Results The mRNA transcripts of most P2 receptors were detected in primary B cells; the expression of P2X3 and P2X7 receptors was the lowest of all the P2 receptors. By contrast, LCLs expressed several dominant P2 receptors – P2X4, P2X5, and P2Y11 – in amounts similar to those seen in B cells infected with EBV for 2 weeks. The amount of most P2 subtypes in LCLs or EBV-infected B cells was lower than in normal B cells. However, the amount of P2X7 receptor expressed in LCLs was higher. Protein expression was studied using Western blotting to confirm the mRNA findings for P2X1, P2X4, P2X7, P2Y1, and P2Y11 receptors. ATP increased the intracellular free Ca2+ concentration ([Ca2+]i) by enhancing the Ca2+ influx in both B cells and LCLs in a dose-dependent manner. Conclusion These findings describe P2 receptor expression profiles and the effects of purinergic stimuli on B cells and suggest some plasticity in the expression of the P2 receptor phenotype. This may help explain the nature and effect of P2 receptors on B cells and their role in altering the characteristics of LCLs.
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Affiliation(s)
- Dong Hyeon Lee
- Biobank for Health Sciences, Center for Genome Sciences, National Institute of Health, Korea Center for Disease Control and Prevention, Seoul, South Korea
| | - Kyu Sang Park
- Department of Physiology, Institute of Basic Medical Science, Yonsei University, Wonju College of Medicine, Wonju, South Korea
| | - In Deok Kong
- Department of Physiology, Institute of Basic Medical Science, Yonsei University, Wonju College of Medicine, Wonju, South Korea
| | - Jun Woo Kim
- Biobank for Health Sciences, Center for Genome Sciences, National Institute of Health, Korea Center for Disease Control and Prevention, Seoul, South Korea
| | - Bok Ghee Han
- Biobank for Health Sciences, Center for Genome Sciences, National Institute of Health, Korea Center for Disease Control and Prevention, Seoul, South Korea
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Bours MJL, Swennen ELR, Di Virgilio F, Cronstein BN, Dagnelie PC. Adenosine 5'-triphosphate and adenosine as endogenous signaling molecules in immunity and inflammation. Pharmacol Ther 2006; 112:358-404. [PMID: 16784779 DOI: 10.1016/j.pharmthera.2005.04.013] [Citation(s) in RCA: 782] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 04/20/2005] [Indexed: 02/07/2023]
Abstract
Human health is under constant threat of a wide variety of dangers, both self and nonself. The immune system is occupied with protecting the host against such dangers in order to preserve human health. For that purpose, the immune system is equipped with a diverse array of both cellular and non-cellular effectors that are in continuous communication with each other. The naturally occurring nucleotide adenosine 5'-triphosphate (ATP) and its metabolite adenosine (Ado) probably constitute an intrinsic part of this extensive immunological network through purinergic signaling by their cognate receptors, which are widely expressed throughout the body. This review provides a thorough overview of the effects of ATP and Ado on major immune cell types. The overwhelming evidence indicates that ATP and Ado are important endogenous signaling molecules in immunity and inflammation. Although the role of ATP and Ado during the course of inflammatory and immune responses in vivo appears to be extremely complex, we propose that their immunological role is both interdependent and multifaceted, meaning that the nature of their effects may shift from immunostimulatory to immunoregulatory or vice versa depending on extracellular concentrations as well as on expression patterns of purinergic receptors and ecto-enzymes. Purinergic signaling thus contributes to the fine-tuning of inflammatory and immune responses in such a way that the danger to the host is eliminated efficiently with minimal damage to healthy tissues.
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Affiliation(s)
- M J L Bours
- Maastricht University, Department of Epidemiology, Nutrition and Toxicology Research Institute Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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Bernhard MK, Ulrich K. RT-PCR study of purinergic P2 receptors in hematopoietic cell lines. BIOCHEMISTRY (MOSCOW) 2006; 71:607-11. [PMID: 16827651 DOI: 10.1134/s0006297906060034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Seven P2X and fifteen P2Y receptors have been identified to date, partly on the basis of amino acid sequence homologies. The expression of all cloned human purinergic P2 receptors was investigated on the messenger RNA level in promonocytic U937 cells, erythroblastic K562 cells, and undifferentiated, dimethyl sulfoxide-differentiated granulocytic, and phorbol-12-myristate-13-acetate-differentiated monocytic HL60 cells. RT-PCR assays showed expression of several P2X receptors, whereas all P2Y receptors were found in at least some of the analyzed cells lines. Granulocytic and monocytic differentiation of HL60 cells lead to a partly dramatic up- or downregulation of receptor transcripts. The number of different P2 receptors expressed in each cell type showed a significant rise from U937 cells via K562 cells, undifferentiated and granulocytic, to monocytic HL60 cells. The total mRNA amounts being normalized to the glyceraldehyde-3-phosphate dehydrogenase levels demonstrated an even more distinct variability of absolute transcript levels. An increased number of different P2 receptors expressed were associated with an increased total average P2 receptor mRNA amount in each cell. This phenomenon of overexpression suggests self-inductive effects of purinergic signaling indicating its involvement in hematopoiesis and possibly in immunoreactive mediation.
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Affiliation(s)
- M K Bernhard
- Children's Hospital, University of Leipzig, Leipzig, D-04317, Germany.
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28
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Williams M, Raddatz R. Receptors as drug targets. CURRENT PROTOCOLS IN PHARMACOLOGY 2006; Chapter 1:Unit 1.1. [PMID: 22294163 DOI: 10.1002/0471141755.ph0101s32] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Receptors, located on both the cell surface and within the cell, are the molecular targets through which drugs produce their beneficial effects in various disease states. Receptors were initially conceptualized at the beginning of the 20th century by the parallel efforts of Ehrlich and Langley. The concepts of the receptor and receptor theory, based on the Law of Mass Action, have undergone continuous refinement as they have been characterized in terms of their molecular structure, association with ancillary proteins (e.g., G proteins, arrestins, RAMPs), and functional characteristics in normal and diseased tissues. The concepts describing ligand interactions with receptors have also been refined from the simple binary concept of competitive agonists and antagonists to partial agonists, allosteric modulators and inverse agonists. Concepts such as receptor constitutive activity, internalization and dimerization add additional complexity to the role of receptors in tissue function and in precisely characterizing their role in homeostasis and disease.
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Affiliation(s)
- Michael Williams
- Worldwide Discovery Research Cephalon, Inc., West Chester, Pennsylvania, USA
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29
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Entringer PF, Gondim KC, Meyer-Fernandes JR. Ecto-nucleotidase activities in the fat body of Rhodnius prolixus. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2006; 61:1-9. [PMID: 16380977 DOI: 10.1002/arch.20087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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30
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Leal DBR, Streher CA, Neu TN, Bittencourt FP, Leal CAM, da Silva JEP, Morsch VM, Schetinger MRC. Characterization of NTPDase (NTPDase1; ecto-apyrase; ecto-diphosphohydrolase; CD39; EC 3.6.1.5) activity in human lymphocytes. Biochim Biophys Acta Gen Subj 2004; 1721:9-15. [PMID: 15652174 DOI: 10.1016/j.bbagen.2004.09.006] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 09/15/2004] [Accepted: 09/28/2004] [Indexed: 11/28/2022]
Abstract
Human lymphocytes contain NTPDase (NTPDase-1; ecto-apyrase; ecto-diphosphohydrolase; CD39; EC 3.6.1.5), a cation-dependent enzyme that hydrolyzes ATP and ADP and also other di- and triphosphate nucleosides, acting at an optimum pH of 8.0. A significant inhibition of ATP and ADP hydrolysis (P<0.05) was observed in the presence of 20 mM sodium azide. NTPDase inhibitors, 20 mM sodium fluoride, 0.2 mM trifluoperazine and 0.3 mM suramin, significantly decreased ATP and ADP hydrolysis (P<0.05) and ADP hydrolysis was only inhibited by 0.5 mM orthovanadate (P<0.05). ATP and ADP hydrolysis was not inhibited in the presence of 0.01 mM Ap5A (P1,P5-di(adenosine-5')pentaphosphate), 0.1 mM ouabain, 1 mM levamisole, 2 microg/mL oligomycin, 0.1 mM N-ethylmaleimide (NEM), or 5 mM sodium azide. With respect to kinetic behavior, apparent K(m) values of 77.6+/-10.2 and 106.8+/-21.0 microM, and V(max) values of 68.9+/-8.1 and 99.4+/-8.5 (mean+/-S.E., n=3) nmol Pi/min/mg protein were obtained for ATP and ADP, respectively. A Chevilard plot demonstrated that only one enzymatic site is responsible for the hydrolysis of ATP and ADP. The presence of CD39 was determined by flow cytometry, showing a low density of 2.72+/-0.24% (mean+/-S.E.; n=30) in human peripheral lymphocytes. The study of NTPDase activity in human lymphocytes may be important to determine the immune response status against infectious agents related to ATP and ADP hydrolysis.
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Affiliation(s)
- Daniela B R Leal
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcellos, 2600-Anexo, 90035-003. Porto Alegre, RS, Brazil
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31
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Beigi RD, Kertesy SB, Aquilina G, Dubyak GR. Oxidized ATP (oATP) attenuates proinflammatory signaling via P2 receptor-independent mechanisms. Br J Pharmacol 2004; 140:507-19. [PMID: 14522842 PMCID: PMC1574058 DOI: 10.1038/sj.bjp.0705470] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Periodate-oxidized ATP (oATP), which covalently modifies nucleotide-binding proteins, can significantly attenuate proinflammatory signaling. Although the P2X7 nucleotide receptor (P2X7R) is irreversibly antagonized by oATP, it is unclear whether anti-inflammatory actions of oATP are predominantly mediated via its actions on P2X7R. Here, we describe inhibitory effects of oATP on proinflammatory responses in three human cell types that lack expression of P2X7R: human umbilical vein endothelial cells (HUVEC), HEK293 cells, and 1321N1 astrocytes. oATP decreased by 40-70% the secretion of interleukin (IL)-8 stimulated by tumor necrosis factor-alpha (TNF-alpha) in all three cell types, by IL-1beta in HUVEC and 1321N1 cells, and by endotoxin in HUVEC. Attenuation of TNF-alpha-stimulated IL-8 secretion by oATP was similar in wild-type HEK cells or HEK cells stably expressing recombinant P2X7R. oATP also attenuated cytokine-stimulated expression of nuclear factor-kappaB-luciferase reporter genes expressed in HEK or 1321N1 cells, but did not affect the rapid downregulation of IkappaB. oATP had no effect on uridine triphosphate-induced activation of native P2Y2 receptors in HEK cells, but reduced the potency and efficacy of ADP as an agonist of native P2Y1 receptors. However, inhibition of P2Y1 receptors with the specific antagonist MRS2216 did not mimic the effects of oATP on TNF-alpha-stimulated IL-8 secretion. Although 1321N1 astrocytes lack expression of any known P2 receptor subtypes, oATP markedly inhibited ecto-ATPase activity in these cells, resulting in a significant accumulation of extracellular ATP. In summary, oATP can attenuate proinflammatory signaling by mechanisms independent of the expression or activation of known P2 receptor subtypes.
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Affiliation(s)
- Reza D Beigi
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, U.S.A
| | - Sylvia B Kertesy
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, U.S.A
| | - Gretchen Aquilina
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, U.S.A
| | - George R Dubyak
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, U.S.A
- Author for correspondence:
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Hopfe M, Henrich B. OppA, the substrate-binding subunit of the oligopeptide permease, is the major Ecto-ATPase of Mycoplasma hominis. J Bacteriol 2004; 186:1021-928. [PMID: 14761996 PMCID: PMC344229 DOI: 10.1128/jb.186.4.1021-1028.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most ATPases, involved in energy-driven processes, act in the cytoplasm. However, external membrane-bound ATPases have also been described in parasites and eukaryotic cells. In Mycoplasma hominis, a bacterium lacking a cell wall, the surface-exposed substrate-binding protein OppA of an oligopeptide permease (Opp) contains an ATP binding P-loop structure in the C-terminal region. With ATP affinity chromatography and tryptic digestion in the presence or absence of ATP, the functionality of the Mg(2+)-dependent ATP binding site is demonstrated. In addition to ATP, ADP also could bind to OppA. The presence of an ATPase activity on the surface of M. hominis is indicated by the inactivation of ATP hydrolyzing activity of intact mycoplasma cells by the impermeable ATPase inhibitor 4',4'-diisothiocyanostilbene-2',2'-disulfonic acid and influenced by the ATP analog 5'-fluorosulfonyl-benzoyladenosine. Comparing equimolar amounts of OppA in intact mycoplasma cells and in the purified form indicated that more than 80% of the surface-localized ATPase activity is derived from OppA, implying that OppA is the main ATPase on the surface of mycoplasma cells. Together, these data present the first evidence that the cytoadhesive substrate binding protein OppA of the oligopeptide permease also functions as an ecto-ATPase in Mycoplasma hominis.
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Affiliation(s)
- Miriam Hopfe
- Institute of Medical Microbiology and Center for Biological and Medical Research, Heinrich Heine University, 40225 Duesseldorf, Germany.
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33
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Abstract
In the past forty years, a wealth of information has accumulated that points to the presence of adenosine and adenine nucleotides in the anterior segment of the eye and a number of hypotheses have been introduced to describe the possible role of these agents in the regulation of aqueous humor flow. However, in the absence of a generally accepted model for the cellular and molecular mechanisms of aqueous humor formation by the ciliary body epithelium, efforts to identify the signal transduction pathway(s) responsible for regulation of the ion and water transport have not been successful. This article briefly reviews the evidence for (i). the presence in aqueous humor of adenine nucleotides, cyclic adenosine monophosphate and adenosine, their metabolic product, (ii). the possible role of these agents in the regulation of aqueous humor dynamics, and (iii). the expression of ecto-nucleotidases, receptors, and second messengers that may mediate such regulation. Finally, a model for the regulation of aqueous humor formation by adenosine and ATP is proposed.
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Affiliation(s)
- Nasser A Farahbakhsh
- Department of Physiological Science, University of California, Los Angeles, California, 90095-1527, USA.
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Burnstock G, Knight GE. Cellular Distribution and Functions of P2 Receptor Subtypes in Different Systems. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 240:31-304. [PMID: 15548415 DOI: 10.1016/s0074-7696(04)40002-3] [Citation(s) in RCA: 584] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review is aimed at providing readers with a comprehensive reference article about the distribution and function of P2 receptors in all the organs, tissues, and cells in the body. Each section provides an account of the early history of purinergic signaling in the organ?cell up to 1994, then summarizes subsequent evidence for the presence of P2X and P2Y receptor subtype mRNA and proteins as well as functional data, all fully referenced. A section is included describing the plasticity of expression of P2 receptors during development and aging as well as in various pathophysiological conditions. Finally, there is some discussion of possible future developments in the purinergic signaling field.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Institute, Royal Free and University College Medical School, London NW3 2PF, United Kingdom
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35
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Meshki J, Tuluc F, Bredetean O, Ding Z, Kunapuli SP. Molecular mechanism of nucleotide-induced primary granule release in human neutrophils: role for the P2Y2 receptor. Am J Physiol Cell Physiol 2003; 286:C264-71. [PMID: 14613890 DOI: 10.1152/ajpcell.00287.2003] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nucleotides are released during vascular injury from activated platelets and broken cells, which could stimulate human neutrophils. In this study, we characterized the P2Y receptors and investigated the functional effects of extracellular nucleotides on human neutrophils. Pharmacological characterization using selective agonists and pertussis toxin revealed that human neutrophils express only functional P2Y2 receptors. However, P2Y2 receptor agonists ATP or uridine triphosphate (UTP) caused intracellular Ca2+ increases in isolated human neutrophils with an EC50 of 1 microM but failed to cause release of primary granules from human neutrophils. ATP and UTP were equally potent in causing elastase release from human neutrophils in the presence of exogenous soluble fibrinogen, whereas ADP and UDP were without effect. We investigated whether nucleotides depend on generated arachidonic acid metabolites to cause degranulation. However, phenidone and MK-886, inhibitors of the 5-lipoxygenase pathway, failed to block nucleotide-induced intracellular calcium mobilization and elastase release. ATP and UTP caused activation of p38 MAPK and ERK1/2 in human neutrophils. In addition, the inhibitors of the MAPK pathway, SB-203580 and U-0126, inhibited nucleotide-induced elastase release. We conclude that fibrinogen is required for nucleotide-induced primary granule release from human neutrophils through the P2Y2 receptor without a role for arachidonic acid metabolites. Both ERK1/2 and p38 MAPK play an important role in nucleotide-induced primary granule release from human neutrophils.
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Affiliation(s)
- John Meshki
- Department of Physiology, Temple University Medical School, 3420 N. Broad St., Philadelphia, PA, 19140, USA
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36
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Sak K, Boeynaems JM, Everaus H. Involvement of P2Y receptors in the differentiation of haematopoietic cells. J Leukoc Biol 2003; 73:442-7. [PMID: 12660218 DOI: 10.1189/jlb.1102561] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The effects of extracellular nucleotides are mediated by multiple P2X ionotropic receptors and G protein-coupled P2Y receptors. These receptors are ubiquitous, but few physiological roles have been firmly identified. In this review article, we present a survey of the functional expression of P2Y receptors in the different haematopoietic lineages by analyzing the selectivity of these cells for the various adenine and uracil nucleotides as well as the second messenger signaling pathways involved. The pharmacological profiles of metabotropic nucleotide receptors are different among myeloid, megakaryoid, erythroid, and lymphoid cells and change during differentiation. A role of P2Y receptors in the differentiation and maturation of blood cells has been proposed: In particular the P2Y(11)receptor seems to be involved in the granulocytic differentiation of promyelocytes and in the maturation of monocyte-derived dendritic cells. It is suggested that the role of P2Y receptors in the maturation of blood cells may be more important than believed so far.
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Affiliation(s)
- Katrin Sak
- Hematology-Oncology Clinic, University of Tartu, Estonia.
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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 ecto-enzymes, can be measured using living cells. Cell membrane ecto-ATPases are integral membrane glycoproteins that are millimolar divalent cation-dependent, low specificity enzymes that hydrolyze all nucleoside triphosphates. Their physiological role is still unknown. However, several hypotheses have been suggested such as; (i). protection from cytolytic effects of extracellular ATP, (ii). regulation of ectokinase substrate concentration, (iii). termination of purinergic signaling, (iv). involvement in signal transduction, and (v). involvement in cellular adhesion. In this review, the biochemical properties and possible functions of the ecto-ATPases of different protozoa are summarized.
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Affiliation(s)
- José Roberto Meyer-Fernandes
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, CCS, Bloco H-20 andar-sala 13, Cidade Universitária, Ilha do Fundão, 21541-590, RJ, Rio de Janeiro, Brazil.
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Canaday DH, Beigi R, Silver RF, Harding CV, Boom WH, Dubyak GR. ATP and control of intracellular growth of mycobacteria by T cells. Infect Immun 2002; 70:6456-9. [PMID: 12379727 PMCID: PMC130300 DOI: 10.1128/iai.70.11.6456-6459.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extracellular ATP at millimolar concentrations inhibits growth of mycobacteria in human macrophages. Whether T cells can produce sufficient ATP is unknown. CD4(+) and CD8(+) T cells did not release sufficient ATP through either degranulation or lysis of bystander cells to restrict growth of Mycobacterium bovis BCG in monocytes.
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Affiliation(s)
- David H Canaday
- Department of Medicine, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio 44109, USA.
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Yegutkin GG, Henttinen T, Samburski SS, Spychala J, Jalkanen S. The evidence for two opposite, ATP-generating and ATP-consuming, extracellular pathways on endothelial and lymphoid cells. Biochem J 2002; 367:121-8. [PMID: 12099890 PMCID: PMC1222875 DOI: 10.1042/bj20020439] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2002] [Accepted: 07/05/2002] [Indexed: 11/17/2022]
Abstract
Extracellular purines are important signalling molecules in the vasculature that are regulated by a network of cell surface ectoenzymes. By using human endothelial cells and normal and leukaemic lymphocytes as enzyme sources, we identified the following purine-converting ectoenzymes: (1) ecto-nucleotidases, NTP diphosphohydrolase/CD39 (EC 3.6.1.5) and ecto-5'-nucleotidase/CD73 (EC 3.1.3.5); (2) ecto-nucleotide kinases, adenylate kinase (EC 2.7.4.3) and nucleoside diphosphate kinase (EC 2.7.4.6); (3) ecto-adenosine deaminase (EC 3.5.4.4). Evidence for this was obtained by using enzyme assays with (3)H-labelled nucleotides and adenosine as substrates, direct evaluation of gamma-phosphate transfer from [gamma-(32)P]ATP to AMP/NDP, and bioluminescent measurement of extracellular ATP synthesis. In addition, incorporation of radioactivity into an approx. 20 kDa surface protein was observed following incubation of Namalwa B cells with [gamma-(32)P]ATP. Thus two opposite, ATP-generating and ATP-consuming, pathways coexist on the cell surface, where basal ATP release, re-synthesis of high-energy phosphoryls, and selective ecto-protein phosphorylation are counteracted by stepwise nucleotide breakdown with subsequent adenosine inactivation. The comparative measurements of enzymic activities indicated the predominance of the nucleotide-inactivating pathway via ecto-nucleotidase reactions on the endothelial cells. The lymphocytes are characterized by counteracting ATP-regenerating/adenosine-eliminating phenotypes, thus allowing them to avoid the lymphotoxic effects of adenosine and maintain surrounding ATP at a steady-state level. These results are in agreement with divergent effects of ATP and adenosine on endothelial function and haemostasis, and provide a novel regulatory mechanism of local agonist availability for nucleotide- or nucleoside-selective receptors within the vasculature.
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Affiliation(s)
- Gennady G Yegutkin
- MediCity Research Laboratory, Turku University and National Public Health Institute, Tykistökatu 6A, FIN-20520 Turku, Finland.
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40
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Mattana A, Cappai V, Alberti L, Serra C, Fiori PL, Cappuccinelli P. ADP and other metabolites released from Acanthamoeba castellanii lead to human monocytic cell death through apoptosis and stimulate the secretion of proinflammatory cytokines. Infect Immun 2002; 70:4424-32. [PMID: 12117953 PMCID: PMC128125 DOI: 10.1128/iai.70.8.4424-4432.2002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monocytes/macrophages are thought to be involved in Acanthamoeba infections. The aim of this work was to study whether soluble metabolites (ADP and other compounds) released by Acanthamoeba castellanii trophozoites could induce morphological and biochemical changes in human monocytic cells in vitro. We demonstrate here that ADP constitutively released in the medium by A. castellanii, interacting with specific P2y(2) purinoceptors expressed on the monocytic cell membrane, caused a biphasic rise in [Ca(2+)](i), morphological changes characteristics of cells undergoing apoptosis, caspase-3 activation, and secretion of tumor necrosis factor alpha (TNF-alpha). The same results were found in monocytes exposed to purified ADP. Cell damage and TNF-alpha release induced by amoebic ADP were blocked by the P2y(2) inhibitor suramin. Other metabolites contained in amoebic cell-free supernatants, with molecular masses of, respectively, >30 kDa and between 30 and 10 kDa, also caused morphological modifications and activation of intracellular caspase-3, characteristics of programmed cell death. Nevertheless, mechanisms by which these molecules trigger cell damage appeared to differ from that of ADP. In addition, other amoebic thermolable metabolites with molecular masses of <10 kDa caused the secretion of interleukin-1beta. These findings suggest that pathogenic free-living A. castellanii by release of ADP and other metabolites lead to human monocytic cell death through apoptosis and stimulate the secretion of proinflammatory cytokines.
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Affiliation(s)
- A Mattana
- Department of Pharmaceutical Sciences, University of Sassari, Italy.
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41
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Abstract
Snake envenomation employs three well integrated strategies: prey immobilization via hypotension, prey immobilization via paralysis, and prey digestion. Purines (adenosine, guanosine and inosine) evidently play a central role in the envenomation strategies of most advanced snakes. Purines constitute the perfect multifunctional toxins, participating simultaneously in all three envenomation strategies. Because they are endogenous regulatory compounds in all vertebrates, it is impossible for any prey organism to develop resistance to them. Purine generation from endogenous precursors in the prey explains the presence of many hitherto unexplained enzyme activities in snake venoms: 5'-nucleotidase, endonucleases (including ribonuclease), phosphodiesterase, ATPase, ADPase, phosphomonoesterase, and NADase. Phospholipases A(2), cytotoxins, myotoxins, and heparinase also participate in purine liberation, in addition to their better known functions. Adenosine contributes to prey immobilization by activation of neuronal adenosine A(1) receptors, suppressing acetylcholine release from motor neurons and excitatory neurotransmitters from central sites. It also exacerbates venom-induced hypotension by activating A(2) receptors in the vasculature. Adenosine and inosine both activate mast cell A(3) receptors, liberating vasoactive substances and increasing vascular permeability. Guanosine probably contributes to hypotension, by augmenting vascular endothelial cGMP levels via an unknown mechanism. Novel functions are suggested for toxins that act upon blood coagulation factors, including nitric oxide production, using the prey's carboxypeptidases. Leucine aminopeptidase may link venom hemorrhagic metalloproteases and endogenous chymotrypsin-like proteases with venom L-amino acid oxidase (LAO), accelerating the latter. The primary function of LAO is probably to promote prey hypotension by activating soluble guanylate cyclase in the presence of superoxide dismutase. LAO's apoptotic activity, too slow to be relevant to prey capture, is undoubtedly secondary and probably serves principally a digestive function. It is concluded that the principal function of L-type Ca(2+) channel antagonists and muscarinic toxins, in Dendroaspis venoms, and acetylcholinesterase in other elapid venoms, is to promote hypotension. Venom dipeptidyl peptidase IV-like enzymes probably also contribute to hypotension by destroying vasoconstrictive peptides such as Peptide YY, neuropeptide Y and substance P. Purines apparently bind to other toxins which then serve as molecular chaperones to deposit the bound purines at specific subsets of purine receptors. The assignment of pharmacological activities such as transient neurotransmitter suppression, histamine release and antinociception, to a variety of proteinaceous toxins, is probably erroneous. Such effects are probably due instead to purines bound to these toxins, and/or to free venom purines.
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Affiliation(s)
- Steven D Aird
- Laboratório de Toxinas Naturais, Universidade Estadual do Ceará, Avenida Paranjana, 1700, Itaperí, 60740-000, Fortaleza, CE, Brazil.
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Jesus JB, Lopes AHCS, Meyer-Fernandes JR. Characterization of an ecto-ATPase of Tritrichomonas foetus. Vet Parasitol 2002; 103:29-42. [PMID: 11750998 DOI: 10.1016/s0304-4017(01)00576-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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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43
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Moore DJ, Chambers JK, Wahlin JP, Tan KB, Moore GB, Jenkins O, Emson PC, Murdock PR. Expression pattern of human P2Y receptor subtypes: a quantitative reverse transcription-polymerase chain reaction study. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1521:107-19. [PMID: 11690642 DOI: 10.1016/s0167-4781(01)00291-3] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The diverse biological actions of extracellular nucleotides in tissues and cells are mediated by two distinct classes of P2 receptor, P2X and P2Y. The G protein-coupled P2Y receptors comprise at least six mammalian subtypes (P2Y(1,2,4,6,11,12)), all of which have been cloned from human tissues, as well as other species. The P2Y receptor subtypes differ in their pharmacological selectivity for various adenosine and uridine nucleotides, which overlap in some cases. Data concerning the mRNA expression patterns of five P2Y receptors (P2Y(1,2,4,6,11)) in different human tissues and cells are currently quite limited, while P2Y mRNA distribution in the human brain has not previously been studied. In this study, we have addressed this deficiency in receptor expression data by using a quantitative reverse transcription-polymerase chain reaction approach to measure the precise mRNA expression pattern of each P2Y receptor subtype in a number of human peripheral tissues and brain regions, from multiple individuals, as well as numerous human cell lines and primary cells. All five P2Y receptors exhibited widespread yet subtype-selective mRNA expression profiles throughout the human tissues, brain regions and cells used. Our extensive expression data indicate the many potentially important roles of P2Y receptors throughout the human body, and will help in elucidating the physiological function of each receptor subtype in a wide variety of human systems.
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Affiliation(s)
- D J Moore
- Neurobiology Programme, The Babraham Institute, Cambridege, UK.
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44
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Kannan S. Neutrophil degranulation: coactivation of chemokine receptor(s) is required for extracellular nucleotide-induced neutrophil degranulation. Med Hypotheses 2001; 57:306-9. [PMID: 11516221 DOI: 10.1054/mehy.2001.1313] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Extracellular nucleotide-induced stimulation of leukocytes and subsequent adhesion to endothelium plays a critical role in inflammatory diseases. The extracellular nucleotides stimulate a P2Y receptor on human PMN with the pharmacological profile of the P2Y2 receptor. Followed by generation of arachidonic acid, subsequently metabolized by 5 lipoxygenase forming the leukotrienes (LT). Of the several LTs generated, LTB(4)is a potent chemokine and upon its release binds to the PMN in an autocrine manner leading to the PMN degranulation. It is known that LTB(4)causes neutrophil degranulation through its receptor specific binding while the molecular mechanism remains not known at present. However, it is not known whether any LTB(4)receptor exists in cytoplasm in any given cell type and also, the existence of any other signaling cascade for the extracellular nucleotide-induced neutrophil degranulation. Based on the few direct experimental and numerous circumstantial evidence, it is conceivable that the extracellular nucleotides require LT generation, as an essential intermediate for mediating neutrophil degranulation.
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Affiliation(s)
- S Kannan
- Department of Physiology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, USA.
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Robson SC, Enjyoji K, Goepfert C, Imai M, Kaczmarek E, Lin Y, Sévigny J, Warny M. Modulation of extracellular nucleotide-mediated signaling by CD39/nucleoside triphosphate diphosphohydrolase-1. Drug Dev Res 2001. [DOI: 10.1002/ddr.1188] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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46
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Koziolkiewicz M, Gendaszewska E, Maszewska M, Stein CA, Stec WJ. The mononucleotide-dependent, nonantisense mechanism of action of phosphodiester and phosphorothioate oligonucleotides depends upon the activity of an ecto-5'-nucleotidase. Blood 2001; 98:995-1002. [PMID: 11493444 DOI: 10.1182/blood.v98.4.995] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many reports indicate different nonantisense yet sequence-specific effects of antisense phosphorothioate oligonucleotides. Products of enzymatic degradation of the oligonucleotides can also influence cell proliferation. The cytotoxic effects of deoxyribonucleoside-5'-phosphates (dNMPs) and their 5'-phosphorothioate analogs, deoxyribonucleoside-5'-monophosphorothioates (dNMPSs) on 4 human cell types (HeLa, HL-60, K-562, and endothelial cells) were examined, and the effects were correlated with the catabolism of these compounds. The results indicate that differences in cytotoxicity of dNMPs or dNMPSs in these cells depend upon different activity of an ecto-5'-nucleotidase. It has also been found that dNMPSs stimulate proliferation of human umbilical vein endothelial cells and HL-60 cells in a concentration-dependent manner. This stimulation might be caused by the binding of deoxynucleoside-5'-phosphorothioates to as-yet unidentified nucleotide receptor(s) at the cell surface. (Blood. 2001;98:995-1002)
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Affiliation(s)
- M Koziolkiewicz
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Łódz,
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47
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Watters JJ, Sommer JA, Fisette PL, Pfeiffer ZA, Aga M, Prabhu U, Guerra AN, Denlinger LC, Bertics PJ. P2X7 nucleotide receptor: Modulation of LPS-induced macrophage signaling and mediator production. Drug Dev Res 2001. [DOI: 10.1002/ddr.1176] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Warny M, Aboudola S, Robson SC, Sévigny J, Communi D, Soltoff SP, Kelly CP. P2Y(6) nucleotide receptor mediates monocyte interleukin-8 production in response to UDP or lipopolysaccharide. J Biol Chem 2001; 276:26051-6. [PMID: 11349132 DOI: 10.1074/jbc.m102568200] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Extracellular nucleotides are autocrine and paracrine cellular mediators that signal through P2 nucleotide receptors. Monocytic cells express several P2Y receptors but the role of these G protein-coupled receptors in monocytes is not known. Here, we present evidence that P2Y(6) regulates chemokine production and release in monocytes. We find that UDP, a selective P2Y(6) agonist, stimulates interleukin (IL)-8 release in human THP-1 monocytic cells whereas other nucleotides are relatively inactive. P2 receptor antagonists or P2Y(6) antisense oligonucleotides inhibit IL-8 release induced by UDP. Furthermore, UDP specifically activated IL-8 production in astrocytoma 1321N1 cells transfected with human P2Y(6). Since lipopolysaccharide has been suggested to activate P2 receptors via nucleotide release, we tested whether IL-8 production stimulated by lipopolysaccharide might result from P2Y(6) activation. P2 antagonists or apyrase, an enzyme which hydrolyzes nucleotides including UDP, inhibit IL-8 production induced by lipopolysaccharide but not by other stimuli. Furthermore, IL-8 gene expression activated by lipopolysaccharide is enhanced by P2Y(6) overexpression and inhibited by P2Y(6) antisense oligonucleotides. Thus, UDP activates IL-8 production via P2Y(6) in monocytic cells. Furthermore, lipopolysaccharide mediates IL-8 production at least in part by autocrine P2Y(6) activation. These findings indicate a novel role for P2Y(6) in innate immune defenses.
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Affiliation(s)
- M Warny
- Gastroenterology Divison, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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Abstract
Concepts regarding the mechanisms by which drugs activate receptors to produce physiological response have progressed beyond considering the receptor as a simple on-off switch. Current evidence suggests that the idea that agonists produce only varying degrees of receptor activation is obsolete and must be reconciled with data to show that agonist efficacy has texture as well as magnitude. Thus, agonists can block system constitutive response (inverse agonists), behave as positive and inverse agonists on the same receptor (protean agonists), and differ in the stimulus pattern they produce in physiological systems (ligand-selective agonists). The molecular mechanism for this seemingly diverse array of activities is the same, namely, the selective microaffinity of ligands for different conformational states of the receptor. This paper reviews evidence for the existence of the various types of agonism and the potential therapeutic utility of different agonist types.-Kenakin, T. Inverse, protean, and ligand-selective agonism: matters of receptor conformation.
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Affiliation(s)
- T Kenakin
- Department of Receptor Biochemistry, Glaxo SmithKline Research and Development, Research Triangle Park, North Carolina 27709, USA.
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