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Huang YA, Chen JC, Wu CC, Hsu CW, Ko AMS, Chen LC, Kuo ML. Reducing Lung ATP Levels and Alleviating Asthmatic Airway Inflammation through Adeno-Associated Viral Vector-Mediated CD39 Expression. Biomedicines 2021; 9:biomedicines9060656. [PMID: 34201190 PMCID: PMC8228057 DOI: 10.3390/biomedicines9060656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/03/2021] [Accepted: 06/03/2021] [Indexed: 12/04/2022] Open
Abstract
Asthma is a chronic respiratory inflammatory disease. Patients usually suffer long-term symptoms and high medical expenses. Extracellular ATP (eATP) has been identified as a danger signal in innate immunity and serves as a potent inflammatory mediator for asthma. Hydrolyzing eATP in lungs might be a potential approach to alleviate asthmatic inflammation. Recombinant adeno-associated virus (rAAV) vectors that contain tissue-specific cap protein have been demonstrated to efficiently transfer exogenous genes into the lung tissues. To test anti-inflammation efficacy of rAAV-mediated CD39 gene transfer, rAAV-CD39 was generated and applied to OVA-mediated asthmatic mice. BALB/c mice were sensitized intraperitoneally and challenged intratracheally with OVA and treated with rAAV-CD39. At the end of procedure, some inflammatory features were examined. rAAV-CD39 treatment downregulated the levels of pulmonary eATP by the rescued expression of CD39. Several asthmatic features, such as airway hyperresponsiveness, eosinophilia, mucin deposition, and IL-5/IL-13 production in the lungs were decreased in the rAAV-CD39-treated mice. Reduced IL-5/IL-13 production and increased frequency of CD4+FoxP3+ regulatory T cells were detected in draining lymph nodes of rAAV-CD39 treated mice. This evidence suggested that rAAV-mediated CD39 gene transfer attenuated the asthmatic airway inflammation locally. The results suggest that rAAV-CD39 might have therapeutic potential for asthma.
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Affiliation(s)
- Yung-An Huang
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan;
- Department of Medicine, University of California, San Diego, CA 92093, USA
| | - Jeng-Chang Chen
- Department of Surgery, Chang Gung Memorial Hospital-Linkou, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan;
| | - Chih-Ching Wu
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan;
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Chia-Wei Hsu
- Department of Otolaryngology—Head and Neck Surgery, Chang Gung Memorial Hospital-Linkou, Taoyuan 33302, Taiwan;
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11574, Taiwan
| | - Albert Min-Shan Ko
- Department of Cardiovascular Diseases, Chang Gung Memorial Hospital-Linkou, Taoyuan 33302, Taiwan;
| | - Li-Chen Chen
- Department of Pediatrics, Division of Allergy, Asthma, and Rheumatology, Chang Gung Memorial Hospital-Linkou, Taoyuan 33302, Taiwan;
- Department of Pediatrics, New Taipei Municipal TuCheng Hospital, New Taipei City 23664, Taiwan
| | - Ming-Ling Kuo
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan;
- Department of Cardiovascular Diseases, Chang Gung Memorial Hospital-Linkou, Taoyuan 33302, Taiwan;
- Department of Pediatrics, New Taipei Municipal TuCheng Hospital, New Taipei City 23664, Taiwan
- Correspondence: ; Tel.: +886-3-2118800 (ext. 3319)
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Woods PS, Doolittle LM, Hickman-Davis JM, Davis IC. ATP catabolism by tissue nonspecific alkaline phosphatase contributes to development of ARDS in influenza-infected mice. Am J Physiol Lung Cell Mol Physiol 2017; 314:L83-L92. [PMID: 28982733 DOI: 10.1152/ajplung.00149.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Influenza A viruses are highly contagious respiratory pathogens that are responsible for significant morbidity and mortality worldwide on an annual basis. We have shown previously that influenza infection of mice leads to increased ATP and adenosine accumulation in the airway lumen. Moreover, we demonstrated that A1-adenosine receptor activation contributes significantly to influenza-induced acute respiratory distress syndrome (ARDS). However, we found that development of ARDS in influenza-infected mice does not require catabolism of ATP to adenosine by ecto-5'-nucleotidase (CD73). Hence, we hypothesized that increased adenosine generation in response to infection is mediated by tissue nonspecific alkaline phosphatase (TNAP), which is a low-affinity, high-capacity enzyme that catabolizes nucleotides in a nonspecific manner. In the current study, we found that whole lung and BALF TNAP expression and alkaline phosphatase enzymatic activity increased as early as 2 days postinfection (dpi) of C57BL/6 mice with 10,000 pfu/mouse of influenza A/WSN/33 (H1N1). Treatment at 2 and 4 dpi with a highly specific quinolinyl-benzenesulfonamide TNAP inhibitor (TNAPi) significantly reduced whole lung alkaline phosphatase activity at 6 dpi but did not alter TNAP gene or protein expression. TNAPi treatment attenuated hypoxemia, lung dysfunction, histopathology, and pulmonary edema at 6 dpi without impacting viral replication or BALF adenosine. Treatment also improved epithelial barrier function and attenuated cellular and humoral immune responses to influenza infection. These data indicate that TNAP inhibition can attenuate influenza-induced ARDS by reducing inflammation and fluid accumulation within the lung. They also further emphasize the importance of adenosine generation for development of ARDS in influenza-infected mice.
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Affiliation(s)
- Parker S Woods
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio
| | - Lauren M Doolittle
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio
| | - Judy M Hickman-Davis
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio
| | - Ian C Davis
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio
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Margaroli C, Tirouvanziam R. Neutrophil plasticity enables the development of pathological microenvironments: implications for cystic fibrosis airway disease. Mol Cell Pediatr 2016; 3:38. [PMID: 27868161 PMCID: PMC5136534 DOI: 10.1186/s40348-016-0066-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 11/04/2016] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION The pathological course of several chronic inflammatory diseases, including cystic fibrosis, chronic obstructive pulmonary disease, and rheumatoid arthritis, features an aberrant innate immune response dominated by neutrophils. In cystic fibrosis, neutrophil burden and activity of neutrophil elastase in the extracellular fluid have been identified as strong predictors of lung disease severity. REVIEW Although neutrophils are generally considered to be rigid, pre-programmed effector leukocytes, recent studies suggest extensive plasticity in how neutrophil functions unfold upon recruitment to peripheral tissues, and how they choose their ultimate fate. Indeed, upon migration to cystic fibrosis airways, neutrophils display dysregulated lifespan, metabolic activation, and altered effector and regulatory functions, consistent with profound adaptation and phenotypic reprogramming. Licensed by signals present in cystic fibrosis airway microenvironment to survive and develop these novel functions, neutrophils orchestrate, in partnership with the epithelium and with the resident microbiota, the evolution of a pathological microenvironment. This microenvironment is defined by altered proteolytic, redox, and metabolic balance and the presence of stable luminal structures in which neutrophils and microbes coexist. CONCLUSIONS The elucidation of molecular mechanisms driving neutrophil plasticity in vivo will open new treatment opportunities designed to modulate, rather than block, the crucial adaptive functions fulfilled by neutrophils. This review aims to outline emerging mechanisms of neutrophil plasticity and their participation in the building of pathological microenvironments in the context of cystic fibrosis and other diseases with similar features.
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Affiliation(s)
- Camilla Margaroli
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Center for CF and Airways Disease Research, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
- Emory + Children's Center, 2015 Uppergate Dr NE, Rm 344, Atlanta, GA, 30322-1014, USA
| | - Rabindra Tirouvanziam
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Center for CF and Airways Disease Research, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA.
- Emory + Children's Center, 2015 Uppergate Dr NE, Rm 344, Atlanta, GA, 30322-1014, USA.
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Bromberg PA. Mechanisms of the acute effects of inhaled ozone in humans. Biochim Biophys Acta Gen Subj 2016; 1860:2771-81. [PMID: 27451958 DOI: 10.1016/j.bbagen.2016.07.015] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/13/2016] [Accepted: 07/18/2016] [Indexed: 12/31/2022]
Abstract
Ambient air ozone (O3) is generated photochemically from oxides of nitrogen and volatile hydrocarbons. Inhaled O3 causes remarkably reversible acute lung function changes and inflammation. Approximately 80% of inhaled O3 is deposited on the airways. O3 reacts rapidly with CC double bonds in hydrophobic airway and alveolar surfactant-associated phospholipids and cholesterol. Resultant primary ozonides further react to generate bioactive hydrophilic products that also initiate lipid peroxidation leading to eicosanoids and isoprostanes of varying electrophilicity. Airway surface liquid ascorbate and urate also scavenge O3. Thus, inhaled O3 may not interact directly with epithelial cells. Acute O3-induced lung function changes are dominated by involuntary inhibition of inspiration (rather than bronchoconstriction), mediated by stimulation of intraepithelial nociceptive vagal C-fibers via activation of transient receptor potential (TRP) A1 cation channels by electrophile (e.g., 4-oxo-nonenal) adduction of TRPA1 thiolates enhanced by PGE2-stimulated sensitization. Acute O3-induced neutrophilic airways inflammation develops more slowly than the lung function changes. Surface macrophages and epithelial cells are involved in the activation of epithelial NFkB and generation of proinflammatory mediators such as IL-6, IL-8, TNFa, IL-1b, ICAM-1, E-selectin and PGE2. O3-induced partial depolymerization of hyaluronic acid and the release of peroxiredoxin-1 activate macrophage TLR4 while oxidative epithelial cell release of EGFR ligands such as TGFa or EGFR transactivation by activated Src may also be involved. The ability of lipid ozonation to generate potent electrophiles also provides pathways for Nrf2 activation and inhibition of canonical NFkB activation. This article is part of a Special Issue entitled Air Pollution, edited by Wenjun Ding, Andrew J. Ghio and Weidong Wu.
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Affiliation(s)
- Philip A Bromberg
- Center for Environmental Medicine, Asthma and Lung Biology, and Division of Pulmonary and Critical Care Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
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Lazar Z, Müllner N, Lucattelli M, Ayata CK, Cicko S, Yegutkin GG, De Cunto G, Müller T, Meyer A, Hossfeld M, Sorichter S, Horvath I, Virchow CJ, Robson SC, Lungarella G, Idzko M. NTPDase1/CD39 and aberrant purinergic signalling in the pathogenesis of COPD. Eur Respir J 2016; 47:254-63. [PMID: 26541524 DOI: 10.1183/13993003.02144-2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 08/05/2015] [Indexed: 01/06/2023]
Abstract
Purinergic receptor activation via extracellular ATP is involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Nucleoside triphosphate diphosphohydrolase-1/CD39 hydrolyses extracellular ATP and modulates P2 receptor signalling.We aimed to investigate the expression and function of CD39 in the pathogenesis of cigarette smoke-induced lung inflammation in patients and preclinical mouse models. CD39 expression and soluble ATPase activity were quantified in sputum and bronchoalveolar lavage fluid (BALF) cells in nonsmokers, smokers and COPD patients or mice with cigarette smoke-induced lung inflammation. In mice, pulmonary ATP and cytokine concentrations, inflammation and emphysema were analysed in the presence or absence of CD39.Following acute cigarette smoke exposure CD39 was upregulated in BALF cells in smokers with further increases in COPD patients. Acute cigarette smoke exposure induced CD39 upregulation in murine lungs and BALF cells, and ATP degradation was accelerated in airway fluids. CD39 inhibition and deficiency led to augmented lung inflammation; treatment with ATPase during cigarette smoke exposure prevented emphysema.Pulmonary CD39 expression and activity are increased in COPD. CD39 deficiency leads to enhanced emphysema in mice, while external administration of a functional CD39 analogue partially rescues the phenotype. The compensatory upregulation of pulmonary CD39 might serve as a protective mechanism in cigarette smoke-induced lung damage.
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Affiliation(s)
- Zsofia Lazar
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany Dept of Pulmonology, Semmelweis University, Budapest, Hungary These authors contributed equally
| | - Nina Müllner
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany These authors contributed equally
| | - Monica Lucattelli
- Dept of Life Sciences, University of Siena, Siena, Italy These authors contributed equally
| | - Cemil Korcan Ayata
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany These authors contributed equally
| | - Sanja Cicko
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany
| | | | | | - Tobias Müller
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany
| | - Anja Meyer
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany
| | - Madelon Hossfeld
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany
| | - Stephan Sorichter
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany
| | - Ildiko Horvath
- Dept of Pulmonology, Semmelweis University, Budapest, Hungary
| | | | - Simon C Robson
- Division of Gastroenterology, Dept of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Marco Idzko
- Dept of Pulmonology, University Hospital Freiburg, Freiburg, Germany
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Aeffner F, Woods PS, Davis IC. Ecto-5'-nucleotidase CD73 modulates the innate immune response to influenza infection but is not required for development of influenza-induced acute lung injury. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1313-22. [PMID: 26432867 PMCID: PMC4669338 DOI: 10.1152/ajplung.00130.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/27/2015] [Indexed: 11/22/2022] Open
Abstract
Extracellular nucleotides and nucleosides are important signaling molecules in the lung. Nucleotide and nucleoside concentrations in alveolar lining fluid are controlled by a complex network of surface ectonucleotidases. Previously, we demonstrated that influenza A/WSN/33 (H1N1) virus resulted in increased levels of the nucleotide ATP and the nucleoside adenosine in bronchoalveolar lavage fluid (BALF) of wild-type (WT) C57BL/6 mice. Influenza-induced acute lung injury (ALI) was highly attenuated in A1-adenosine receptor-knockout mice. Because AMP hydrolysis by the ecto-5'-nucleotidase (CD73) plays a central role in and is rate-limiting for generation of adenosine in the normal lung, we hypothesized that ALI would be attenuated in C57BL/6-congenic CD73-knockout (CD73-KO) mice. Infection-induced hypoxemia, bradycardia, viral replication, and bronchoconstriction were moderately increased in CD73-KO mice relative to WT controls. However, postinfection weight loss, pulmonary edema, and parenchymal dysfunction were not altered. Treatment of WT mice with the CD73 inhibitor 5'-(α,β-methylene) diphosphate (APCP) also had no effect on infection-induced pulmonary edema but modestly attenuated hypoxemia. BALF from CD73-KO and APCP-treated WT mice contained more IL-6 and CXCL-10/IFN-γ-induced protein 10, less CXCL-1/keratinocyte chemoattractant, and fewer neutrophils than BALF from untreated WT controls. BALF from APCP-treated WT mice also contained fewer alveolar macrophages and more transforming growth factor-β than BALF from untreated WT mice. These results indicate that CD73 is not necessary for development of ALI following influenza A virus infection and suggest that tissue-nonspecific alkaline phosphatase may be responsible for increased adenosine generation in the infected lung. However, they do suggest that CD73 has a previously unrecognized immunomodulatory role in influenza.
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Affiliation(s)
- Famke Aeffner
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
| | - Parker S Woods
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
| | - Ian C Davis
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
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Salleron L, Magistrelli G, Mary C, Fischer N, Bairoch A, Lane L. DERA is the human deoxyribose phosphate aldolase and is involved in stress response. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2913-25. [PMID: 25229427 DOI: 10.1016/j.bbamcr.2014.09.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/13/2014] [Accepted: 09/07/2014] [Indexed: 10/24/2022]
Abstract
Deoxyribose-phosphate aldolase (EC 4.1.2.4), which converts 2-deoxy-d-ribose-5-phosphate into glyceraldehyde-3-phosphate and acetaldehyde, belongs to the core metabolism of living organisms. It was previously shown that human cells harbor deoxyribose phosphate aldolase activity but the protein responsible of this activity has never been formally identified. This study provides the first experimental evidence that DERA, which is mainly expressed in lung, liver and colon, is the human deoxyribose phosphate aldolase. Among human cell lines, the highest DERA mRNA level and deoxyribose phosphate aldolase activity were observed in liver-derived Huh-7 cells. DERA was shown to interact with the known stress granule component YBX1 and to be recruited to stress granules after oxidative or mitochondrial stress. In addition, cells in which DERA expression was down-regulated using shRNA formed fewer stress granules and were more prone to apoptosis after clotrimazole stress, suggesting the importance of DERA for stress granule formation. Furthermore, the expression of DERA was shown to permit cells in which mitochondrial ATP production was abolished to make use of extracellular deoxyinosine to maintain ATP levels. This study unraveled a previously undescribed pathway which may allow cells with high deoxyribose-phosphate aldolase activity, such as liver cells, to minimize or delay stress-induced damage by producing energy through deoxynucleoside degradation.
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Affiliation(s)
- Lisa Salleron
- Department of Human Protein Sciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
| | | | - Camille Mary
- Department of Human Protein Sciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | | | - Amos Bairoch
- Department of Human Protein Sciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland; CALIPHO GroupSIB-Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Lydie Lane
- Department of Human Protein Sciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland; CALIPHO GroupSIB-Swiss Institute of Bioinformatics, Geneva, Switzerland.
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Laval J, Touhami J, Herzenberg LA, Conrad C, Taylor N, Battini JL, Sitbon M, Tirouvanziam R. Metabolic adaptation of neutrophils in cystic fibrosis airways involves distinct shifts in nutrient transporter expression. THE JOURNAL OF IMMUNOLOGY 2013; 190:6043-50. [PMID: 23690474 DOI: 10.4049/jimmunol.1201755] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inflammatory conditions can profoundly alter human neutrophils, a leukocyte subset generally viewed as terminally differentiated and catabolic. In cystic fibrosis (CF) patients, neutrophils recruited to CF airways show active exocytosis and sustained phosphorylation of prosurvival, metabolic pathways. Because the CF airway lumen is also characterized by high levels of free glucose and amino acids, we compared surface expression of Glut1 (glucose) and ASCT2 (neutral amino acids) transporters, as well as that of PiT1 and PiT2 (inorganic phosphate transporters), in blood and airway neutrophils, using specific retroviral envelope-derived ligands. Neither nutrient transporter expression nor glucose uptake was altered on blood neutrophils from CF patients compared with healthy controls. Notably, however, airway neutrophils of CF patients had higher levels of PiT1 and Glut1 and increased glucose uptake compared with their blood counterparts. Based on primary granule exocytosis and scatter profiles, CF airway neutrophils could be divided into two subsets, with one of the subsets characterized by more salient increases in Glut1, ASCT2, PiT1, and PiT2 expression. Moreover, in vitro exocytosis assays of blood neutrophils suggest that surface nutrient transporter expression is not directly associated with primary (or secondary) granule exocytosis. Although expression of nutrient transporters on CF blood or airway neutrophils was not altered by genotype, age, gender, or Pseudomonas aeruginosa infection, oral steroid treatment decreased Glut1 and PiT2 levels in blood neutrophils. Thus, neutrophils recruited from blood into the CF airway lumen display augmented cell surface nutrient transporter expression and glucose uptake, consistent with metabolic adaptation.
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Affiliation(s)
- Julie Laval
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
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Chávez J, Vargas MH, Rebollar-Ayala DC, Díaz-Hernández V, Cruz-Valderrama JE, Flores-Soto E, Flores-García M, Jiménez-Vargas NN, Barajas-López C, Montaño LM. Inhibition of extracellular nucleotides hydrolysis intensifies the allergic bronchospasm. A novel protective role of ectonucleotidases. Allergy 2013; 68:462-71. [PMID: 23414231 DOI: 10.1111/all.12113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2012] [Indexed: 01/31/2023]
Abstract
BACKGROUND Nucleotides released to the extracellular space stimulate purinergic receptors, and their effects are modulated by ectonucleotidases. The role of ATP in the allergic bronchospasm has been scantly studied. METHODS We used several techniques (plethysmography, organ baths, confocal microscopy, RT-PCR, ATP measurement) to explore the role of nucleotides and ectonucleotidases in the allergic bronchospasm in guinea pigs. RESULTS While allergenic challenge with a low-dose ovalbumin (OVA) only produced a small bronchospasm (~2-fold the basal lung resistance), previous inhibition of ectonucleotidases by ARL-67156 greatly intensified this response (~11-fold the basal lung resistance, with 44% mortality). Bronchoalveolar lavage fluid obtained during this bronchospasm contained increased ATP concentration. This potentiation was abolished by antagonism of purinergic receptors (suramin+RB2) or TXA2 receptor (SQ29548), or by intratracheal apyrase. In tracheal rings and lung parenchyma strips, OVA caused a concentration-dependent contraction. Suramin+RB2 or levamisole produced a significant rightward displacement of this response, and ARL-67156 did not modify it. Platelets stimulated with OVA released ATP. Confocal images of nonsensitized tracheas showed slight fluorescence for P2Y6 receptors in epithelium and none for P2Y4 . Sensitized animals showed strong fluorescence to both receptors and to alkaline phosphatase in the airway epithelium. This correlated with a large increment in mRNA for P2Y4 and P2Y6 receptors in sensitized animals. CONCLUSIONS Nucleotides greatly potentiate the allergic bronchospasm when ectonucleotidases activity is diminished, and this effect is probably favored by the upregulation of P2Y4 and P2Y6 receptors in airway epithelium during sensitization. These results prompt for further research on these mechanisms in human asthma.
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Affiliation(s)
- J. Chávez
- Departamento de Investigación en Hiperreactividad Bronquial; Instituto Nacional de Enfermedades Respiratorias; México; DF; México
| | - M. H. Vargas
- Departamento de Investigación en Hiperreactividad Bronquial; Instituto Nacional de Enfermedades Respiratorias; México; DF; México
| | - D. C. Rebollar-Ayala
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - V. Díaz-Hernández
- Departamento de Embriología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - J. E. Cruz-Valderrama
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - E. Flores-Soto
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - M. Flores-García
- Departamento de Biología Molecular; Instituto Nacional de Cardiología; México; DF; México
| | - N. N. Jiménez-Vargas
- División de Biología Molecular; Instituto Potosino de Investigación Científica y Tecnológica; San Luis Potosí; S.L.P.; México
| | - C. Barajas-López
- División de Biología Molecular; Instituto Potosino de Investigación Científica y Tecnológica; San Luis Potosí; S.L.P.; México
| | - L. M. Montaño
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
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