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Assoni L, Couto AJM, Vieira B, Milani B, Lima AS, Converso TR, Darrieux M. Animal models of Klebsiella pneumoniae mucosal infections. Front Microbiol 2024; 15:1367422. [PMID: 38559342 PMCID: PMC10978692 DOI: 10.3389/fmicb.2024.1367422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Klebsiella pneumoniae is among the most relevant pathogens worldwide, causing high morbidity and mortality, which is worsened by the increasing rates of antibiotic resistance. It is a constituent of the host microbiota of different mucosa, that can invade and cause infections in many different sites. The development of new treatments and prophylaxis against this pathogen rely on animal models to identify potential targets and evaluate the efficacy and possible side effects of therapeutic agents or vaccines. However, the validity of data generated is highly dependable on choosing models that can adequately reproduce the hallmarks of human diseases. The present review summarizes the current knowledge on animal models used to investigate K. pneumoniae infections, with a focus on mucosal sites. The advantages and limitations of each model are discussed and compared; the applications, extrapolations to human subjects and future modifications that can improve the current techniques are also presented. While mice are the most widely used species in K. pneumoniae animal studies, they present limitations such as the natural resistance to the pathogen and difficulties in reproducing the main steps of human mucosal infections. Other models, such as Drosophila melanogaster (fruit fly), Caenorhabditis elegans, Galleria mellonella and Danio rerio (zebrafish), contribute to understanding specific aspects of the infection process, such as bacterial lethality and colonization and innate immune system response, however, they but do not present the immunological complexity of mammals. In conclusion, the choice of the animal model of K. pneumoniae infection will depend mainly on the questions being addressed by the study, while a better understanding of the interplay between bacterial virulence factors and animal host responses will provide a deeper comprehension of the disease process and aid in the development of effective preventive/therapeutic strategies.
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Affiliation(s)
| | | | | | | | | | | | - Michelle Darrieux
- Laboratório de Microbiologia Molecular e Clínica, Universidade São Francisco, Bragança Paulista, Brazil
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2
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Strickland LN, Faraoni EY, Ruan W, Yuan X, Eltzschig HK, Bailey-Lundberg JM. The resurgence of the Adora2b receptor as an immunotherapeutic target in pancreatic cancer. Front Immunol 2023; 14:1163585. [PMID: 37187740 PMCID: PMC10175829 DOI: 10.3389/fimmu.2023.1163585] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 04/19/2023] [Indexed: 05/17/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense desmoplastic stroma that impedes drug delivery, reduces parenchymal blood flow, and suppresses the anti-tumor immune response. The extracellular matrix and abundance of stromal cells result in severe hypoxia within the tumor microenvironment (TME), and emerging publications evaluating PDAC tumorigenesis have shown the adenosine signaling pathway promotes an immunosuppressive TME and contributes to the overall low survival rate. Hypoxia increases many elements of the adenosine signaling pathway, resulting in higher adenosine levels in the TME, further contributing to immune suppression. Extracellular adenosine signals through 4 adenosine receptors (Adora1, Adora2a, Adora2b, Adora3). Of the 4 receptors, Adora2b has the lowest affinity for adenosine and thus, has important consequences when stimulated by adenosine binding in the hypoxic TME. We and others have shown that Adora2b is present in normal pancreas tissue, and in injured or diseased pancreatic tissue, Adora2b levels are significantly elevated. The Adora2b receptor is present on many immune cells, including macrophages, dendritic cells, natural killer cells, natural killer T cells, γδ T cells, B cells, T cells, CD4+ T cells, and CD8+ T cells. In these immune cell types, adenosine signaling through Adora2b can reduce the adaptive anti-tumor response, augmenting immune suppression, or may contribute to transformation and changes in fibrosis, perineural invasion, or the vasculature by binding the Adora2b receptor on neoplastic epithelial cells, cancer-associated fibroblasts, blood vessels, lymphatic vessels, and nerves. In this review, we discuss the mechanistic consequences of Adora2b activation on cell types in the tumor microenvironment. As the cell-autonomous role of adenosine signaling through Adora2b has not been comprehensively studied in pancreatic cancer cells, we will also discuss published data from other malignancies to infer emerging therapeutic considerations for targeting the Adora2b adenosine receptor to reduce the proliferative, invasive, and metastatic potential of PDAC cells.
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Affiliation(s)
| | | | | | | | | | - Jennifer M. Bailey-Lundberg
- Department of Anesthesiology, Critical Care, and Pain Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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3
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Mitochondrial ROS production by neutrophils is required for host antimicrobial function against Streptococcus pneumoniae and is controlled by A2B adenosine receptor signaling. PLoS Pathog 2022; 18:e1010700. [DOI: 10.1371/journal.ppat.1010700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 11/28/2022] [Accepted: 11/07/2022] [Indexed: 11/15/2022] Open
Abstract
Polymorphonuclear cells (PMNs) control Streptococcus pneumoniae (pneumococcus) infection through various antimicrobial activities. We previously found that reactive oxygen species (ROS) were required for optimal antibacterial function, however, the NADPH oxidase is known to be dispensable for the ability of PMNs to kill pneumococci. In this study, we explored the role of ROS produced by the mitochondria in PMN antimicrobial defense against pneumococci. We found that the mitochondria are an important source of overall intracellular ROS produced by murine PMNs in response to infection. We investigated the host and bacterial factors involved and found that mitochondrial ROS (MitROS) are produced independent of bacterial capsule or pneumolysin but presence of live bacteria that are in direct contact with PMNs enhanced the response. We further found that MyD88-/- PMNs produced less MitROS in response to pneumococcal infection suggesting that released bacterial products acting as TLR ligands are sufficient for inducing MitROS production in PMNs. To test the role of MitROS in PMN function, we used an opsonophagocytic killing assay and found that MitROS were required for the ability of PMNs to kill pneumococci. We then investigated the role of MitROS in host resistance and found that MitROS are produced by PMNs in response to pneumococcal infection. Importantly, treatment of mice with a MitROS scavenger prior to systemic challenge resulted in reduced survival of infected hosts. In exploring host pathways that control MitROS, we focused on extracellular adenosine, which is known to control PMN anti-pneumococcal activity, and found that signaling through the A2B adenosine receptor inhibits MitROS production by PMNs. A2BR-/- mice produced more MitROS and were significantly more resistant to infection. Finally, we verified the clinical relevance of our findings using human PMNs. In summary, we identified a novel pathway that controls MitROS production by PMNs, shaping host resistance against S. pneumoniae.
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High PANX1 Expression Leads to Neutrophil Recruitment and the Formation of a High Adenosine Immunosuppressive Tumor Microenvironment in Basal-like Breast Cancer. Cancers (Basel) 2022; 14:cancers14143369. [PMID: 35884429 PMCID: PMC9323990 DOI: 10.3390/cancers14143369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 07/03/2022] [Accepted: 07/05/2022] [Indexed: 12/07/2022] Open
Abstract
Background: A high adenosine level is an important characteristic of the tumor microenvironment (TME) in breast cancer. Pannexin 1 (PANX1) can release intracellular ATP to the extracellular space and elevate extracellular ATP (exATP) levels under physiological conditions. Methods: We performed public database bioinformatics analysis, surgical specimen histological validation, RNA sequencing, and exATP/extracellular adenosine (exADO) assays to reveal the role of PANX1 in regulating the immune microenvironment of basal-like breast cancer. Results: Our results revealed that PANX1 acted as a poor prognostic factor for breast cancer and had high expression in basal-like breast cancer. PANX1 expression was positively correlated with exATP and exADO levels in basal-like breast cancer TME. PANX1 expression was also positively correlated with tumor-associated neutrophil (TAN) infiltration in breast cancer TME and TANs highly expressed ENTPD1 (CD39)/NT5E (CD73). Conclusions: This study suggests that high PANX1 expression is associated with high TAN infiltration and adenosine production to induce local immunosuppression in basal-like breast cancer TME.
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Urso A, Prince A. Anti-Inflammatory Metabolites in the Pathogenesis of Bacterial Infection. Front Cell Infect Microbiol 2022; 12:925746. [PMID: 35782110 PMCID: PMC9240774 DOI: 10.3389/fcimb.2022.925746] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/23/2022] [Indexed: 01/13/2023] Open
Abstract
Host and pathogen metabolism have a major impact on the outcome of infection. The microenvironment consisting of immune and stromal cells drives bacterial proliferation and adaptation, while also shaping the activity of the immune system. The abundant metabolites itaconate and adenosine are classified as anti-inflammatory, as they help to contain the local damage associated with inflammation, oxidants and proteases. A growing literature details the many roles of these immunometabolites in the pathogenesis of infection and their diverse functions in specific tissues. Some bacteria, notably P. aeruginosa, actively metabolize these compounds, others, such as S. aureus respond by altering their own metabolic programs selecting for optimal fitness. For most of the model systems studied to date, these immunometabolites promote a milieu of tolerance, limiting local immune clearance mechanisms, along with promoting bacterial adaptation. The generation of metabolites such as adenosine and itaconate can be host protective. In the setting of acute inflammation, these compounds also represent potential therapeutic targets to prevent infection.
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Affiliation(s)
| | - Alice Prince
- *Correspondence: Alice Prince, ; Andreacarola Urso,
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6
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Michels K, Solomon AL, Scindia Y, Sordo Vieira L, Goddard Y, Whitten S, Vaulont S, Burdick MD, Atkinson C, Laubenbacher R, Mehrad B. Aspergillus Utilizes Extracellular Heme as an Iron Source During Invasive Pneumonia, Driving Infection Severity. J Infect Dis 2022; 225:1811-1821. [PMID: 35267014 PMCID: PMC9113461 DOI: 10.1093/infdis/jiac079] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Depriving microbes of iron is critical to host defense. Hemeproteins, the largest source of iron within vertebrates, are abundant in infected tissues in aspergillosis due to hemorrhage, but Aspergillus species have been thought to lack heme import mechanisms. We hypothesized that heme provides iron to Aspergillus during invasive pneumonia, thereby worsening the outcomes of the infection. METHODS We assessed the effect of heme on fungal phenotype in various in vitro conditions and in a neutropenic mouse model of invasive pulmonary aspergillosis. RESULTS In mice with neutropenic invasive aspergillosis, we found a progressive and compartmentalized increase in lung heme iron. Fungal cells cultured under low iron conditions took up heme, resulting in increased fungal iron content, resolution of iron starvation, increased conidiation, and enhanced resistance to oxidative stress. Intrapulmonary administration of heme to mice with neutropenic invasive aspergillosis resulted in markedly increased lung fungal burden, lung injury, and mortality, whereas administration of heme analogs or heme with killed Aspergillus did not. Finally, infection caused by fungal germlings cultured in the presence of heme resulted in a more severe infection. CONCLUSIONS Invasive aspergillosis induces local hemolysis in infected tissues, thereby supplying heme iron to the fungus, leading to lethal infection.
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Affiliation(s)
- Kathryn Michels
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Angelica L Solomon
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Yogesh Scindia
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Luis Sordo Vieira
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Yana Goddard
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Spencer Whitten
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Sophie Vaulont
- Université de Paris, INSERM U1016, Institut Cochin, Paris, France
| | - Marie D Burdick
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Carl Atkinson
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Reinhard Laubenbacher
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Borna Mehrad
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
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7
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Ribeiro HA, Vieira LS, Scindia Y, Adhikari B, Wheeler M, Knapp A, Schroeder W, Mehrad B, Laubenbacher R. Multi-scale mechanistic modelling of the host defence in invasive aspergillosis reveals leucocyte activation and iron acquisition as drivers of infection outcome. J R Soc Interface 2022; 19:20210806. [PMID: 35414216 PMCID: PMC9006013 DOI: 10.1098/rsif.2021.0806] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aspergillus species are ubiquitous environmental moulds, with spores inhaled daily by most humans. Immunocompromised hosts can develop an invasive infection resulting in high mortality. There is, therefore, a pressing need for host-centric therapeutics for this infection. To address it, we created a multi-scale computational model of the infection, focused on its interaction with the innate immune system and iron, a critical nutrient for the pathogen. The model, parameterized using published data, was found to recapitulate a wide range of biological features and was experimentally validated in vivo. Conidial swelling was identified as critical in fungal strains with high growth, whereas the siderophore secretion rate seems to be an essential prerequisite for the establishment of the infection in low-growth strains. In immunocompetent hosts, high growth, high swelling probability and impaired leucocyte activation lead to a high conidial germination rate. Similarly, in neutropenic hosts, high fungal growth was achieved through synergy between high growth rate, high swelling probability, slow leucocyte activation and high siderophore secretion. In summary, the model reveals a small set of parameters related to fungal growth, iron acquisition and leucocyte activation as critical determinants of the fate of the infection.
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Affiliation(s)
- Henrique Al Ribeiro
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
| | - Luis Sordo Vieira
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA.,Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - Yogesh Scindia
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA.,Department of Pathology, University of Florida, Gainesville, FL, USA
| | - Bandita Adhikari
- Center for Quantitative Medicine, School of Medicine, University of Connecticut, Farmington, CT, USA
| | - Matthew Wheeler
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
| | - Adam Knapp
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
| | | | - Borna Mehrad
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
| | - Reinhard Laubenbacher
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
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8
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Pacini ESA, Satori NA, Jackson EK, Godinho RO. Extracellular cAMP-Adenosine Pathway Signaling: A Potential Therapeutic Target in Chronic Inflammatory Airway Diseases. Front Immunol 2022; 13:866097. [PMID: 35479074 PMCID: PMC9038211 DOI: 10.3389/fimmu.2022.866097] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/21/2022] [Indexed: 12/25/2022] Open
Abstract
Adenosine is a purine nucleoside that, via activation of distinct G protein-coupled receptors, modulates inflammation and immune responses. Under pathological conditions and in response to inflammatory stimuli, extracellular ATP is released from damaged cells and is metabolized to extracellular adenosine. However, studies over the past 30 years provide strong evidence for another source of extracellular adenosine, namely the “cAMP-adenosine pathway.” The cAMP-adenosine pathway is a biochemical mechanism mediated by ATP-binding cassette transporters that facilitate cAMP efflux and by specific ectoenzymes that convert cAMP to AMP (ecto-PDEs) and AMP to adenosine (ecto-nucleotidases such as CD73). Importantly, the cAMP-adenosine pathway is operative in many cell types, including those of the airways. In airways, β2-adrenoceptor agonists, which are used as bronchodilators for treatment of asthma and chronic respiratory diseases, stimulate cAMP efflux and thus trigger the extracellular cAMP-adenosine pathway leading to increased concentrations of extracellular adenosine in airways. In the airways, extracellular adenosine exerts pro-inflammatory effects and induces bronchoconstriction in patients with asthma and chronic obstructive pulmonary diseases. These considerations lead to the hypothesis that the cAMP-adenosine pathway attenuates the efficacy of β2-adrenoceptor agonists. Indeed, our recent findings support this view. In this mini-review, we will highlight the potential role of the extracellular cAMP-adenosine pathway in chronic respiratory inflammatory disorders, and we will explore how extracellular cAMP could interfere with the regulatory effects of intracellular cAMP on airway smooth muscle and innate immune cell function. Finally, we will discuss therapeutic possibilities targeting the extracellular cAMP-adenosine pathway for treatment of these respiratory diseases.
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Affiliation(s)
- Enio Setsuo Arakaki Pacini
- Division of Cellular Pharmacology, Department of Pharmacology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Naiara Ayako Satori
- Division of Cellular Pharmacology, Department of Pharmacology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Edwin Kerry Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Rosely Oliveira Godinho
- Division of Cellular Pharmacology, Department of Pharmacology, Universidade Federal de São Paulo, São Paulo, Brazil
- *Correspondence: Rosely Oliveira Godinho,
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9
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Eberhardt N, Bergero G, Mazzocco Mariotta YL, Aoki MP. Purinergic modulation of the immune response to infections. Purinergic Signal 2022; 18:93-113. [PMID: 34997903 PMCID: PMC8742569 DOI: 10.1007/s11302-021-09838-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/17/2021] [Indexed: 02/07/2023] Open
Abstract
Infectious diseases are caused by the invasion of pathogenic microorganisms such as fungi, bacteria, viruses, and parasites. After infection, disease progression relies on the complex interplay between the host immune response and the microorganism evasion strategies. The host's survival depends on its ability to mount an efficient protective anti-microbial response to accomplish pathogen clearance while simultaneously preventing tissue injury by keeping under control the excessive inflammatory process. The purinergic system has the dual function of regulating the immune response and triggering effector antimicrobial mechanisms. This review provides an overview of the current knowledge of the modulation of innate and adaptive immunity driven by the purinergic system during parasitic, bacterial and viral infections.
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Affiliation(s)
- Natalia Eberhardt
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET) - Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Present Address: Department of Medicine, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, USA
| | - Gastón Bergero
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET) - Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Yanina L. Mazzocco Mariotta
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET) - Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M. Pilar Aoki
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET) - Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Haya de La Torre and Medina Allende, Ciudad Universitaria, CP 5000 Córdoba, Argentina
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10
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Cagnina RE, Michels KR, Bettina AM, Burdick MD, Scindia Y, Zhang Z, Braciale TJ, Mehrad B. Neutrophil-Derived Tumor Necrosis Factor Drives Fungal Acute Lung Injury in Chronic Granulomatous Disease. J Infect Dis 2021; 224:1225-1235. [PMID: 33822981 PMCID: PMC8682762 DOI: 10.1093/infdis/jiab188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 04/02/2021] [Indexed: 12/11/2022] Open
Abstract
Chronic granulomatous disease (CGD) results from deficiency of nicotinamide adenine dinucleotide phosphate(NADPH) oxidase and impaired reactive oxygen species (ROS) generation. This leads to impaired killing of Aspergillus and, independently, a pathologic hyperinflammatory response to the organism. We hypothesized that neutrophil-derived ROS inhibit the inflammatory response to Aspergillus and that acute lung injury in CGD is due to failure of this regulation. Mice with gp91phox deficiency, the most common CGD mutation, had more severe lung injury, increased neutrophilinfiltration, and increased lung tumor necrosis factor (TNF) after Aspergillus challenge compared with wild-types. Neutrophils were surprisingly the predominant source of TNF in gp91phox-deficient lungs. TNF neutralization inhibited neutrophil recruitment in gp91phox-deficient mice and protected from lung injury. We propose that, in normal hosts, Aspergillus stimulates TNF-dependent neutrophil recruitment to the lungs and neutrophil-derived ROS limit inflammation. In CGD, in contrast, recruited neutrophils are the dominant source of TNF, promoting further neutrophil recruitment in a pathologic positive-feedback cycle, resulting in progressive lung injury.
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Affiliation(s)
- R Elaine Cagnina
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Kathryn R Michels
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Alexandra M Bettina
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Marie D Burdick
- Division of Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville,Virginia, USA
| | - Yogesh Scindia
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
| | - Zhimin Zhang
- Division of Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville,Virginia, USA
| | - Thomas J Braciale
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, USA
| | - Borna Mehrad
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, USA
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11
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Sundaresh B, Xu S, Noonan B, Mansour MK, Leong JM, van Opijnen T. Host-informed therapies for the treatment of pneumococcal pneumonia. Trends Mol Med 2021; 27:971-989. [PMID: 34376327 DOI: 10.1016/j.molmed.2021.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/06/2021] [Accepted: 07/12/2021] [Indexed: 12/11/2022]
Abstract
Over the past two decades, traditional antimicrobial strategies have lost efficacy due to a rapid rise in antibiotic resistance and limited success in developing new antibiotics. Rather than relying on therapeutics solely targeting the bacterial pathogen, therapies are emerging that simultaneously focus on host responses. Here, we describe the most promising 'host-informed therapies' (HITs) in two categories: those that aid patients with fully functional immune systems, and those that aid patients with perturbed immune processes. Using Streptococcus pneumoniae, the leading cause of bacterial pneumonia, as a case study, we show HITs as an attractive option for supplementing infection management. However, to broaden their applicability and design new strategies, targeted research and clinical trials will be essential.
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Affiliation(s)
| | - Shuying Xu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA; Graduate Program in Immunology, Tufts Graduate School of Biomedical Sciences, Boston, MA, USA
| | - Brian Noonan
- Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Tufts Medical Center, Boston, MA, USA
| | - Michael K Mansour
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA; Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Tufts Medical Center, Boston, MA, USA.
| | - Tim van Opijnen
- Department of Biology, Boston College, Chestnut Hill, MA, USA; Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Tufts Medical Center, Boston, MA, USA.
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12
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Older but Not Wiser: the Age-Driven Changes in Neutrophil Responses during Pulmonary Infections. Infect Immun 2021; 89:IAI.00653-20. [PMID: 33495271 DOI: 10.1128/iai.00653-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Elderly individuals are at increased risk of life-threatening pulmonary infections. Neutrophils are a key determinant of the disease course of pathogen-induced pneumonia. Optimal host defense balances initial robust pulmonary neutrophil responses to control pathogen numbers, ultimately followed by the resolution of inflammation to prevent pulmonary damage. Recent evidence suggests that phenotypic and functional heterogeneity in neutrophils impacts host resistance to pulmonary pathogens. Apart from their apparent role in innate immunity, neutrophils also orchestrate subsequent adaptive immune responses during infection. Thus, the outcome of pulmonary infections can be shaped by neutrophils. This review summarizes the age-driven impairment of neutrophil responses and the contribution of these cells to the susceptibility of the elderly to pneumonia. We describe how aging is accompanied by changes in neutrophil recruitment, resolution, and function. We discuss how systemic and local changes alter the neutrophil phenotype in aged hosts. We highlight the gap in knowledge of whether these changes in neutrophils also contribute to the decline in adaptive immunity seen with age. We further detail the factors that drive dysregulated neutrophil responses in the elderly and the pathways that may be targeted to rebalance neutrophil activity and boost host resistance to pulmonary infections.
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13
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Adenosine and ATPγS protect against bacterial pneumonia-induced acute lung injury. Sci Rep 2020; 10:18078. [PMID: 33093565 PMCID: PMC7581771 DOI: 10.1038/s41598-020-75224-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/08/2020] [Indexed: 12/20/2022] Open
Abstract
Lipopolysaccharide (LPS), a component of the outer membrane of gram-negative bacteria, disrupts the alveolar-capillary barrier, triggering pulmonary vascular leak thus inducing acute lung injury (ALI). Extracellular purines, adenosine and ATP, protected against ALI induced by purified LPS. In this study, we investigated whether these purines can impact vascular injury in more clinically-relevant E.coli (non-sterile LPS) murine ALI model. Mice were inoculated with live E. coli intratracheally (i.t.) with or without adenosine or a non-hydrolyzable ATP analog, adenosine 5'-(γ-thio)-triphosphate (ATPγS) added intravenously (i.v.). After 24 h of E. coli treatment, we found that injections of either adenosine or ATPγS 15 min prior or adenosine 3 h after E.coli insult significantly attenuated the E.coli-mediated increase in inflammatory responses. Furthermore, adenosine prevented weight loss, tachycardia, and compromised lung function in E. coli-exposed mice. Accordingly, treatment with adenosine or ATPγS increased oxygen saturation and reduced histopathological signs of lung injury in mice exposed to E. coli. Lastly, lung-targeting gene delivery of adenosine or ATPγS downstream effector, myosin phosphatase, significantly attenuated the E. coli-induced compromise of lung function. Collectively, our study has demonstrated that adenosine or ATPγS mitigates E. coli-induced ALI in mice and may be useful as an adjuvant therapy in future pre-clinical studies.
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Lin CM, Alrbiaan A, Odackal J, Zhang Z, Scindia Y, Sung SSJ, Burdick MD, Mehrad B. Circulating fibrocytes traffic to the lung in murine acute lung injury and predict outcomes in human acute respiratory distress syndrome: a pilot study. Mol Med 2020; 26:52. [PMID: 32460694 PMCID: PMC7251319 DOI: 10.1186/s10020-020-00176-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 04/27/2020] [Indexed: 02/06/2023] Open
Abstract
Background Fibrosis is an integral component of the pathogenesis of acute lung injury and is associated with poor outcomes in patients with acute respiratory distress syndrome (ARDS). Fibrocytes are bone marrow-derived cells that traffic to injured tissues and contribute to fibrosis; hence their concentration in the peripheral blood has the potential to serve as a biomarker of lung fibrogenesis. We therefore sought to test the hypothesis that the concentration and phenotype of circulating fibrocytes in patients with ARDS predicts clinical outcomes. Methods For the animal studies, C57Bl/6 mice were infected with experimental Klebsiella pneumoniae in a model of acute lung injury; one-way ANOVA was used to compare multiple groups and two-way ANOVA was used to compare two groups over time. For the human study, 42 subjects with ARDS and 12 subjects with pneumonia (without ARDS) were compared to healthy controls. Chi-squared or Fisher’s exact test were used to compare binary outcomes. Survival data was expressed using a Kaplan-Meier curve and compared by log-rank test. Univariable and multivariable logistic regression were used to predict death. Results In mice with acute lung injury caused by Klebsiella pneumonia, there was a time-dependent increase in lung soluble collagen that correlated with sequential expansion of fibrocytes in the bone marrow, blood, and then lung compartments. Correspondingly, when compared via cross-sectional analysis, the initial concentration of blood fibrocytes was elevated in human subjects with ARDS or pneumonia as compared to healthy controls. In addition, fibrocytes from subjects with ARDS displayed an activated phenotype and on serial measurements, exhibited intermittent episodes of markedly elevated concentration over a median of 1 week. A peak concentration of circulating fibrocytes above a threshold of > 4.8 × 106 cells/mL cells correlated with mortality that was independent of age, ratio of arterial oxygen concentration to the fraction of inspired oxygen, and vasopressor requirement. Conclusions Circulating fibrocytes increase in a murine model of acute lung injury and elevation in the number of these cells above a certain threshold is correlated with mortality in human ARDS. Therefore, these cells may provide a useful and easily measured biomarker to predict outcomes in these patients.
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Affiliation(s)
- Christine M Lin
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, 1600 SW Archer Road, Box 100225, Gainesville, FL, 32610-0225, USA
| | - Abdullah Alrbiaan
- Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - John Odackal
- Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Zhimin Zhang
- Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Yogesh Scindia
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, 1600 SW Archer Road, Box 100225, Gainesville, FL, 32610-0225, USA
| | - Sun-Sang J Sung
- Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Marie D Burdick
- Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Borna Mehrad
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, 1600 SW Archer Road, Box 100225, Gainesville, FL, 32610-0225, USA.
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15
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Shi Y, Liu T, Nieman DC, Cui Y, Li F, Yang L, Shi H, Chen P. Aerobic Exercise Attenuates Acute Lung Injury Through NET Inhibition. Front Immunol 2020; 11:409. [PMID: 32265910 PMCID: PMC7096358 DOI: 10.3389/fimmu.2020.00409] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 02/21/2020] [Indexed: 12/12/2022] Open
Abstract
Introduction: Aerobic exercise improves lung inflammation in acute lung injury (ALI), but its mechanism remains unknown. Neutrophil extracellular traps (NETs) play an important role in LPS-induced ALI, and a positive correlation exists between NET formation and proinflammatory macrophage polarization. This study investigated whether aerobic exercise reduces the pro-inflammatory polarization of alveolar macrophages (AMs) by inhibiting the excessive release of NETs and then alleviating the inflammatory response of ALI. Methods: C57BL/6 male mice were randomly divided into four groups: sedentary group (CON), sedentary and extra-pulmonary LPS injection group (LPS), 5-weeks aerobic training intervention and LPS injection group (EXE+LPS), and DNase I plus LPS injection group (DNase+LPS). Twenty-four hours after drug injection, bronchoalveolar lavage fluid (BALF), AM, and lung tissues were obtained to detect inflammatory responses, NET formation, macrophage polarization, and protein activation. In the in vitro study, a murine AM cell line, designated MH-S, was stimulated with LPS, purified NETs, and NETs plus DNase I. Results: EXE+LPS and DNase+LPS mice exhibited reduced neutrophil infiltration, decreased NET release, and lower pro-inflammatory polarization of AM compared with LPS mice. Subsequently, Western blot showed inhibition of the phosphorylation of MAPK and NF-κB proteins of AMs in EXE+LPS and DNase+LPS mice compared with LPS mice. Lastly, stimulation of MH-S cells by NETs revealed a trend for pro-inflammatory cell polarization, with NF-κB protein activation at 8 h and ERK1/2 activation at 1, 2, and 8 h. Conclusions: Aerobic exercise alleviated ALI through NET-induced AM pro-inflammatory polarization involving ERK1/2 and NF-κB signaling.
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Affiliation(s)
- Yue Shi
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Tingting Liu
- Department of Rheumatology and Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - David C Nieman
- North Carolina Research Campus, Appalachian State University, Kannapolis, NC, United States
| | - Yanqiu Cui
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Fei Li
- School of Physical Education and Sport Training, Shanghai University of Sport, Shanghai, China
| | - Luyu Yang
- Department of General Surgery, Cancer Metastasis Institute, Huashan Hospital, Fudan University, Shanghai, China
| | - Hui Shi
- Department of Rheumatology and Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peijie Chen
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
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16
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Serov DA, Astashev ME, Tikhonova IV, Safronova VG. The Influence of Exogenous ATP on Functional Responses of Murine Bone Marrow Granulocytes. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2020. [DOI: 10.1134/s1990747819060096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Siwapornchai N, Lee JN, Tchalla EYI, Bhalla M, Yeoh JH, Roggensack SE, Leong JM, Bou Ghanem EN. Extracellular adenosine enhances the ability of PMNs to kill Streptococcus pneumoniae by inhibiting IL-10 production. J Leukoc Biol 2020; 108:867-882. [PMID: 32017200 DOI: 10.1002/jlb.4ma0120-115rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 01/14/2020] [Accepted: 01/17/2020] [Indexed: 12/18/2022] Open
Abstract
Polymorphonuclear leukocytes (PMNs) are crucial for initial control of Streptococcus pneumoniae (pneumococcus) lung infection; however, as the infection progresses their persistence in the lungs becomes detrimental. Here we explored why the antimicrobial efficacy of PMNs declines over the course of infection. We found that the progressive inability of PMNs to control infection correlated with phenotypic differences characterized by a decrease in CD73 expression, an enzyme required for production of extracellular adenosine (EAD). EAD production by CD73 was crucial for the ability of both murine and human PMNs to kill S. pneumoniae. In exploring the mechanisms by which CD73 controlled PMN function, we found that CD73 mediated its antimicrobial activity by inhibiting IL-10 production. PMNs from wild-type mice did not increase IL-10 production in response to S. pneumoniae; however, CD73-/- PMNs up-regulated IL-10 production upon pneumococcal infection in vitro and during lung challenge. IL-10 inhibited the ability of WT PMNs to kill pneumococci. Conversely, blocking IL-10 boosted the bactericidal activity of CD73-/- PMNs as well as host resistance of CD73-/- mice to pneumococcal pneumonia. CD73/IL-10 did not affect apoptosis, bacterial uptake, and intracellular killing or production of antimicrobial neutrophil elastase and myeloperoxidase. Rather, inhibition of IL-10 production by CD73 was important for optimal reactive oxygen species (ROS) production by PMNs. ROS contributed to PMN antimicrobial function as their removal or detoxification impaired the ability of PMNs to efficiently kill S. pneumoniae. This study demonstrates that CD73 controls PMN antimicrobial phenotype during S. pneumoniae infection.
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Affiliation(s)
- Nalat Siwapornchai
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - James N Lee
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Essi Y I Tchalla
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Manmeet Bhalla
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Jun Hui Yeoh
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Sara E Roggensack
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Elsa N Bou Ghanem
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
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18
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Bhalla M, Hui Yeoh J, Lamneck C, Herring SE, Tchalla EYI, Heinzinger LR, Leong JM, Bou Ghanem EN. A1 adenosine receptor signaling reduces Streptococcus pneumoniae adherence to pulmonary epithelial cells by targeting expression of platelet-activating factor receptor. Cell Microbiol 2019; 22:e13141. [PMID: 31709673 DOI: 10.1111/cmi.13141] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/24/2019] [Accepted: 11/01/2019] [Indexed: 12/11/2022]
Abstract
Extracellular adenosine production is crucial for host resistance against Streptococcus pneumoniae (pneumococcus) and is thought to affect antibacterial immune responses by neutrophils. However, whether extracellular adenosine alters direct host-pathogen interaction remains unexplored. An important determinant for lung infection by S. pneumoniae is its ability to adhere to the pulmonary epithelium. Here we explored whether extracellular adenosine can directly impact bacterial adherence to lung epithelial cells. We found that signaling via A1 adenosine receptor significantly reduced the ability of pneumococci to bind human pulmonary epithelial cells. A1 receptor signaling blocked bacterial binding by reducing the expression of platelet-activating factor receptor, a host protein used by S. pneumoniae to adhere to host cells. In vivo, A1 was required for control of pneumococcal pneumonia as inhibiting it resulted in increased host susceptibility. As S. pneumoniae remain a leading cause of community-acquired pneumonia in the elderly, we explored the role of A1 in the age-driven susceptibility to infection. We found no difference in A1 pulmonary expression in young versus old mice. Strikingly, triggering A1 signaling boosted host resistance of old mice to S. pneumoniae pulmonary infection. This study demonstrates a novel mechanism by which extracellular adenosine modulates resistance to lung infection by targeting bacterial-host interactions.
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Affiliation(s)
- Manmeet Bhalla
- Department of Microbiology and Immunology, State University of New York at Buffalo School of Medicine, Buffalo, New York
| | - Jun Hui Yeoh
- Department of Microbiology and Immunology, State University of New York at Buffalo School of Medicine, Buffalo, New York
| | - Claire Lamneck
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Sydney E Herring
- Department of Microbiology and Immunology, State University of New York at Buffalo School of Medicine, Buffalo, New York
| | - Essi Y I Tchalla
- Department of Microbiology and Immunology, State University of New York at Buffalo School of Medicine, Buffalo, New York
| | - Lauren R Heinzinger
- Department of Microbiology and Immunology, State University of New York at Buffalo School of Medicine, Buffalo, New York
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Elsa N Bou Ghanem
- Department of Microbiology and Immunology, State University of New York at Buffalo School of Medicine, Buffalo, New York
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19
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Abstract
Elsa N. Bou Ghanem works in the field of innate immune senescence, inflammation, and host defense. In this mSphere of Influence article, she reflects on how "Adenosine A2B receptor deficiency promotes host defenses against Gram-negative bacterial pneumonia" by Barletta et al. (K. E. Barletta, R. E. Cagnina, M. D. Burdick, J. Linden, and B. Mehrad, Am J Respir Crit Care Med 186:1044-1050, 2012, https://doi.org/10.1164/rccm.201204-0622OC) impacted her own work examining the role of the extracellular adenosine pathway in neutrophil responses and host defense against pneumococcal pneumonia.
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Affiliation(s)
- Elsa N Bou Ghanem
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
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20
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Wang X, Chen D. Purinergic Regulation of Neutrophil Function. Front Immunol 2018; 9:399. [PMID: 29545806 PMCID: PMC5837999 DOI: 10.3389/fimmu.2018.00399] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/13/2018] [Indexed: 12/28/2022] Open
Abstract
Purinergic signaling, which utilizes nucleotides (particularly ATP) and adenosine as transmitter molecules, plays an essential role in immune system. In the extracellular compartment, ATP predominantly functions as a pro-inflammatory molecule through activation of P2 receptors, whereas adenosine mostly functions as an anti-inflammatory molecule through activation of P1 receptors. Neutrophils are the most abundant immune cells in circulation and have emerged as an important component in orchestrating a complex series of events during inflammation. However, because of the destructive nature of neutrophil-derived inflammatory agents, neutrophil activation is fine-tuned, and purinergic signaling is intimately involved in this process. Indeed, shifting the balance between P2 and P1 signaling is critical for neutrophils to appropriately exert their immunologic activity. Here, we review the role of purinergic signaling in regulating neutrophil function, and discuss the potential of targeting purinergic signaling for the treatment of neutrophil-associated infectious and inflammatory diseases.
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Affiliation(s)
- Xu Wang
- Institute of Oncology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Deyu Chen
- Institute of Oncology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
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21
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Lee JS, Yilmaz Ö. Unfolding Role of a Danger Molecule Adenosine Signaling in Modulation of Microbial Infection and Host Cell Response. Int J Mol Sci 2018; 19:E199. [PMID: 29315226 PMCID: PMC5796148 DOI: 10.3390/ijms19010199] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/10/2017] [Accepted: 01/04/2018] [Indexed: 02/06/2023] Open
Abstract
Ectonucleotidases CD39 and CD73, specific nucleotide metabolizing enzymes located on the surface of the host, can convert a pro-inflammatory environment driven by a danger molecule extracellular-ATP to an adenosine-mediated anti-inflammatory milieu. Accordingly, CD39/CD73 signaling have has strongly implicated in modulating the intensity, duration, and composition of purinergic danger signals delivered to host. Recent studies have eluted potential roles for CD39 and CD73 in selective triggering of a variety of host immune cells and molecules in the presence of pathogenic microorganisms or microbial virulence molecules. Growing evidence also suggests that CD39 and CD73 present complimentary, but likely differential, actions against pathogens to shape the course and severity of microbial infection as well as the associated immune response. Similarly, adenosine receptors A2A and A2B have been proposed to be major immunomodulators of adenosine signaling during chronic inflammatory conditions induced by opportunistic pathogens, such as oral colonizer Porphyromonas gingivalis. Therefore, we here review the recent studies that demonstrate how complex network of molecules in the extracellular adenosine signaling machinery and their interactions can reshape immune responses and may also be targeted by opportunistic pathogens to establish successful colonization in human mucosal tissues and modulate the host immune response.
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Affiliation(s)
- Jaden S Lee
- Department of Oral Health Sciences, College of Dental Medicine, Medical University of South Carolina, 29425 Charleston, SC 29425, USA.
| | - Özlem Yilmaz
- Department of Oral Health Sciences, College of Dental Medicine, Medical University of South Carolina, 29425 Charleston, SC 29425, USA.
- Department of Microbiology and Immunology, Medical University of South Carolina, 29425 Charleston, SC 29425, USA.
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22
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Michels KR, Zhang Z, Bettina AM, Cagnina RE, Stefanova D, Burdick MD, Vaulont S, Nemeth E, Ganz T, Mehrad B. Hepcidin-mediated iron sequestration protects against bacterial dissemination during pneumonia. JCI Insight 2017; 2:e92002. [PMID: 28352667 DOI: 10.1172/jci.insight.92002] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Gram-negative pneumonia is a dangerous illness, and bacterial dissemination to the bloodstream during the infection is strongly associated with death. Antibiotic resistance among the causative pathogens has resulted in diminishing treatment options against this infection. Hepcidin is the master regulator of extracellular iron availability in vertebrates, but its role in the context of host defense is undefined. We hypothesized that hepcidin-mediated depletion of extracellular iron during Gram-negative pneumonia protects the host by limiting dissemination of bacteria to the bloodstream. During experimental pneumonia, hepcidin was induced in the liver in an IL-6-dependent manner and mediated a rapid decline in plasma iron. In contrast, hepcidin-deficient mice developed a paradoxical increase in plasma iron during infection associated with profound susceptibility to bacteremia. Incubation of bacteria with iron-supplemented plasma enhanced bacterial growth in vitro, and systemic administration of iron to WT mice similarly promoted increased susceptibility to bloodstream infection. Finally, treatment with a hepcidin analogue restored hypoferremia in hepcidin-deficient hosts, mediated bacterial control, and improved outcomes. These data show hepcidin induction during pneumonia to be essential to preventing bacterial dissemination by limiting extracellular iron availability. Hepcidin agonists may represent an effective therapy for Gram-negative infections in patients with impaired hepcidin production or signaling.
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Affiliation(s)
| | - Zhimin Zhang
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | | | - R Elaine Cagnina
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Debora Stefanova
- Departments of Molecular, Cellular, and Integrative Physiology, University of California, Los Angeles, California, USA
| | - Marie D Burdick
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Sophie Vaulont
- INSERM U1016, Cochin Institute, Descartes University, Paris, France
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Borna Mehrad
- Departments of Microbiology, Immunology, and Cancer Biology.,Division of Pulmonary & Critical Care Medicine, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA.,Beirne B. Carter Center for Immunology, University of Virginia, Charlottesville, Virginia, USA
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Cortjens B, van Woensel JBM, Bem RA. Neutrophil Extracellular Traps in Respiratory Disease: guided anti-microbial traps or toxic webs? Paediatr Respir Rev 2017; 21:54-61. [PMID: 27424227 DOI: 10.1016/j.prrv.2016.03.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 03/15/2016] [Indexed: 02/07/2023]
Abstract
Neutrophil recruitment to the airways and lungs is a major hallmark of many respiratory diseases. One of the more recently discovered unique innate immune effector mechanisms of neutrophils is the formation of neutrophil extracellular traps (NETs), consisting of an extracellular network of DNA fibers studded with nuclear and granule proteins. Although in the respiratory system NETs contribute to capture and inactivation of bacteria, fungi and viruses, there is a delicate 'balance' between aid and damage to the host. Accumulating evidence now suggests that NETs can have direct cytotoxic effects to lung epithelial and endothelial cells and can contribute to airway obstruction. As such, NETs may play an important role in the pathogenesis of respiratory diseases. The purpose of this review is to give an up-to-date overview of the current status of NETs in respiratory diseases. We examine both experimental and clinical data concerning the role of NETs in host defence as well as immunopathology, with special attention paid to the literature relevant for the paediatric pulmonology community. Finally, we discuss future treatment strategies that may target the formation of NETs in the airways and lungs.
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Affiliation(s)
- B Cortjens
- Paediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital AMC, Amsterdam.
| | - J B M van Woensel
- Paediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital AMC, Amsterdam
| | - R A Bem
- Paediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital AMC, Amsterdam
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Abstract
Klebsiella pneumoniae causes a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically, K. pneumoniae has caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore, K. pneumoniae strains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat. The emergence of hypervirulent and antibiotic-resistant strains has driven a number of recent studies. Work has described the worldwide spread of one drug-resistant strain and a host defense axis, interleukin-17 (IL-17), that is important for controlling infection. Four factors, capsule, lipopolysaccharide, fimbriae, and siderophores, have been well studied and are important for virulence in at least one infection model. Several other factors have been less well characterized but are also important in at least one infection model. However, there is a significant amount of heterogeneity in K. pneumoniae strains, and not every factor plays the same critical role in all virulent Klebsiella strains. Recent studies have identified additional K. pneumoniae virulence factors and led to more insights about factors important for the growth of this pathogen at a variety of tissue sites. Many of these genes encode proteins that function in metabolism and the regulation of transcription. However, much work is left to be done in characterizing these newly discovered factors, understanding how infections differ between healthy and immunocompromised patients, and identifying attractive bacterial or host targets for treating these infections.
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25
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Bettina A, Zhang Z, Michels K, Cagnina RE, Vincent IS, Burdick MD, Kadl A, Mehrad B. M-CSF Mediates Host Defense during Bacterial Pneumonia by Promoting the Survival of Lung and Liver Mononuclear Phagocytes. THE JOURNAL OF IMMUNOLOGY 2016; 196:5047-55. [PMID: 27183631 DOI: 10.4049/jimmunol.1600306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/04/2016] [Indexed: 11/19/2022]
Abstract
Gram-negative bacterial pneumonia is a common and dangerous infection with diminishing treatment options due to increasing antibiotic resistance among causal pathogens. The mononuclear phagocyte system is a heterogeneous group of leukocytes composed of tissue-resident macrophages, dendritic cells, and monocyte-derived cells that are critical in defense against pneumonia, but mechanisms that regulate their maintenance and function during infection are poorly defined. M-CSF has myriad effects on mononuclear phagocytes but its role in pneumonia is unknown. We therefore tested the hypothesis that M-CSF is required for mononuclear phagocyte-mediated host defenses during bacterial pneumonia in a murine model of infection. Genetic deletion or immunoneutralization of M-CSF resulted in reduced survival, increased bacterial burden, and greater lung injury. M-CSF was necessary for the expansion of lung mononuclear phagocytes during infection but did not affect the number of bone marrow or blood monocytes, proliferation of precursors, or recruitment of leukocytes to the lungs. In contrast, M-CSF was essential to survival and antimicrobial functions of both lung and liver mononuclear phagocytes during pneumonia, and its absence resulted in bacterial dissemination to the liver and hepatic necrosis. We conclude that M-CSF is critical to host defenses against bacterial pneumonia by mediating survival and antimicrobial functions of mononuclear phagocytes in the lungs and liver.
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Affiliation(s)
- Alexandra Bettina
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - Zhimin Zhang
- Division of Pulmonary and Critical Care, Department of Medicine, University of Virginia, Charlottesville, VA 22908
| | - Kathryn Michels
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - R Elaine Cagnina
- Division of Pulmonary and Critical Care, Department of Medicine, University of Virginia, Charlottesville, VA 22908
| | - Isaah S Vincent
- Division of Nephrology, Department of Medicine, University of Virginia, Charlottesville, VA 22908
| | - Marie D Burdick
- Division of Pulmonary and Critical Care, Department of Medicine, University of Virginia, Charlottesville, VA 22908
| | - Alexandra Kadl
- Division of Pulmonary and Critical Care, Department of Medicine, University of Virginia, Charlottesville, VA 22908; Department of Pharmacology, University of Virginia, Charlottesville, VA 22908; and
| | - Borna Mehrad
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908; Division of Pulmonary and Critical Care, Department of Medicine, University of Virginia, Charlottesville, VA 22908; Beirne B. Carter Center for Immunology, University of Virginia, Charlottesville, VA 22908
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26
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Parker D, Ahn D, Cohen T, Prince A. Innate Immune Signaling Activated by MDR Bacteria in the Airway. Physiol Rev 2016; 96:19-53. [PMID: 26582515 DOI: 10.1152/physrev.00009.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Health care-associated bacterial pneumonias due to multiple-drug resistant (MDR) pathogens are an important public health problem and are major causes of morbidity and mortality worldwide. In addition to antimicrobial resistance, these organisms have adapted to the milieu of the human airway and have acquired resistance to the innate immune clearance mechanisms that normally prevent pneumonia. Given the limited efficacy of antibiotics, bacterial clearance from the airway requires an effective immune response. Understanding how specific airway pathogens initiate and regulate innate immune signaling, and whether this response is excessive, leading to host-induced pathology may guide future immunomodulatory therapy. We will focus on three of the most important causes of health care-associated pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, and review the mechanisms through which an inappropriate or damaging innate immune response is stimulated, as well as describe how airway pathogens cause persistent infection by evading immune activation.
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Affiliation(s)
- Dane Parker
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Danielle Ahn
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Taylor Cohen
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Alice Prince
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
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Bou Ghanem EN, Clark S, Roggensack SE, McIver SR, Alcaide P, Haydon PG, Leong JM. Extracellular Adenosine Protects against Streptococcus pneumoniae Lung Infection by Regulating Pulmonary Neutrophil Recruitment. PLoS Pathog 2015; 11:e1005126. [PMID: 26313746 PMCID: PMC4552087 DOI: 10.1371/journal.ppat.1005126] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 08/04/2015] [Indexed: 12/15/2022] Open
Abstract
An important determinant of disease following Streptococcus pneumoniae (pneumococcus) lung infection is pulmonary inflammation mediated by polymorphonuclear leukocytes (PMNs). We found that upon intratracheal challenge of mice, recruitment of PMNs into the lungs within the first 3 hours coincided with decreased pulmonary pneumococci, whereas large numbers of pulmonary PMNs beyond 12 hours correlated with a greater bacterial burden. Indeed, mice that survived infection largely resolved inflammation by 72 hours, and PMN depletion at peak infiltration, i.e. 18 hours post-infection, lowered bacterial numbers and enhanced survival. We investigated host signaling pathways that influence both pneumococcus clearance and pulmonary inflammation. Pharmacologic inhibition and/or genetic ablation of enzymes that generate extracellular adenosine (EAD) (e.g. the ectoenzyme CD73) or degrade EAD (e.g. adenosine deaminase) revealed that EAD dramatically increases murine resistance to S. pneumoniae lung infection. Moreover, adenosine diminished PMN movement across endothelial monolayers in vitro, and although inhibition or deficiency of CD73 had no discernible impact on PMN recruitment within the first 6 hours after intratracheal inoculation of mice, these measures enhanced PMN numbers in the pulmonary interstitium after 18 hours of infection, culminating in dramatically elevated numbers of pulmonary PMNs at three days post-infection. When assessed at this time point, CD73-/- mice displayed increased levels of cellular factors that promote leukocyte migration, such as CXCL2 chemokine in the murine lung, as well as CXCR2 and β-2 integrin on the surface of pulmonary PMNs. The enhanced pneumococcal susceptibility of CD73-/- mice was significantly reversed by PMN depletion following infection, suggesting that EAD-mediated resistance is largely mediated by its effects on PMNs. Finally, CD73-inhibition diminished the ability of PMNs to kill pneumococci in vitro, suggesting that EAD alters both the recruitment and bacteriocidal function of PMNs. The EAD-pathway may provide a therapeutic target for regulating potentially harmful inflammatory host responses during Gram-positive bacterial pneumonia. Despite the presence of vaccines and antibiotic therapies, invasive Streptococcus pneumoniae (pneumococcus) infections, such as pneumonia, bacteremia and meningitis, remain a leading cause of mortality and morbidity worldwide. Understanding the host factors that influence the outcome of S. pneumoniae infection will allow us to design better therapies. Here, we elucidate the role of rapidly responding innate immune cells termed neutrophils, or PMNs (polymorphonuclear leukocytes), whose role in S. pneumoniae infection has long been controversial. We found that PMNs are initially required for controlling bacterial numbers, but their extended presence in the lungs leads to significant damage and poor control of infection. The signals that control the movement of PMNs into the infected lungs are not well understood. Here, we identified extracellular adenosine (EAD), a molecule produced by the host in response to cellular damage, as important in limiting PMN movement into the lungs upon pneumococcal challenge. Importantly, EAD-mediated control of PMNs was crucial for fighting lung infection by S. pneumoniae. This study may lead to the potential use of clinically available adenosine-based therapies to combat pneumococcal pneumonia in the future.
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Affiliation(s)
- Elsa N. Bou Ghanem
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Stacie Clark
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Sara E. Roggensack
- Program in Molecular Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
| | - Sally R. McIver
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Pilar Alcaide
- Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Philip G. Haydon
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Extracellular adenosine generation in the regulation of pro-inflammatory responses and pathogen colonization. Biomolecules 2015; 5:775-92. [PMID: 25950510 PMCID: PMC4496696 DOI: 10.3390/biom5020775] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/23/2015] [Accepted: 04/25/2015] [Indexed: 12/17/2022] Open
Abstract
Adenosine, an immunomodulatory biomolecule, is produced by the ecto-enzymes CD39 (nucleoside triphosphate dephosphorylase) and CD73 (ecto-5'-nucleotidase) by dephosphorylation of extracellular ATP. CD73 is expressed by many cell types during injury, infection and during steady-state conditions. Besides host cells, many bacteria also have CD39-CD73-like machinery, which helps the pathogen subvert the host inflammatory response. The major function for adenosine is anti-inflammatory, and most recent research has focused on adenosine's control of inflammatory mechanisms underlying various autoimmune diseases (e.g., colitis, arthritis). Although adenosine generated through CD73 provides a feedback to control tissue damage mediated by a host immune response, it can also contribute to immunosuppression. Thus, inflammation can be a double-edged sword: it may harm the host but eventually helps by killing the invading pathogen. The role of adenosine in dampening inflammation has been an area of active research, but the relevance of the CD39/CD73-axis and adenosine receptor signaling in host defense against infection has received less attention. Here, we review our recent knowledge regarding CD73 expression during murine Salmonellosis and Helicobacter-induced gastric infection and its role in disease pathogenesis and bacterial persistence. We also explored a possible role for the CD73/adenosine pathway in regulating innate host defense function during infection.
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Yang Y, Jiang G, Zhang P, Fan J. Programmed cell death and its role in inflammation. Mil Med Res 2015; 2:12. [PMID: 26045969 PMCID: PMC4455968 DOI: 10.1186/s40779-015-0039-0] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/11/2015] [Indexed: 12/13/2022] Open
Abstract
Cell death plays an important role in the regulation of inflammation and may be the result of inflammation. The maintenance of tissue homeostasis necessitates both the recognition and removal of invading microbial pathogens as well as the clearance of dying cells. In the past few decades, emerging knowledge on cell death and inflammation has enriched our molecular understanding of the signaling pathways that mediate various programs of cell death and multiple types of inflammatory responses. This review provides an overview of the major types of cell death related to inflammation. Modification of cell death pathways is likely to be a logical therapeutic target for inflammatory diseases.
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Affiliation(s)
- Yong Yang
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213 USA ; Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433 China
| | - Gening Jiang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433 China
| | - Peng Zhang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433 China
| | - Jie Fan
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213 USA ; Research and Development, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA 15240 USA
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Spooner R, DeGuzman J, Lee K, Yilmaz Ö. Danger signal adenosine via adenosine 2a receptor stimulates growth of Porphyromonas gingivalis in primary gingival epithelial cells. Mol Oral Microbiol 2014; 29:67-78. [PMID: 24517244 PMCID: PMC3960722 DOI: 10.1111/omi.12045] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2013] [Indexed: 12/20/2022]
Abstract
Extracellular signaling during inflammation and chronic diseases involves molecules referred to as 'Danger Signals' (DS), including the small molecule adenosine. We demonstrate that primary gingival epithelial cells (GEC) express a family of G-protein coupled receptors known as adenosine receptors, including the high-affinity receptors A1 and A2a and low-affinity receptors A2b and A3. Treatment of Porphyromonas gingivalis-infected GEC with the A2a receptor-specific agonist CGS-21680 resulted in elevated intracellular bacterial replication as determined by fluorescence microscopy and antibiotic protection assay. Additionally, A2a receptor antagonism and knockdown via RNA interference significantly reduced metabolically active intracellular P. gingivalis. Furthermore, analysis of anti-inflammatory mediator cyclic AMP (cAMP) following A2a receptor selective agonist CGS-21680 stimulation induced significantly higher levels of cAMP during P. gingivalis infection, indicating that adenosine signaling may attenuate inflammatory processes associated with bacterial infection. This study reveals that the GEC express functional A2a receptor and P. gingivalis may use the A2a receptor coupled DS adenosine signaling as a means to establish successful persistence in the oral mucosa, possibly via downregulation of the pro-inflammatory response.
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Affiliation(s)
- Ralee Spooner
- Department of Periodontology, University of Florida, Gainesville, FL 32610, USA
| | - Jefferson DeGuzman
- Department of Periodontology, University of Florida, Gainesville, FL 32610, USA
| | - KyuLim Lee
- Department of Periodontology, University of Florida, Gainesville, FL 32610, USA
| | - Özlem Yilmaz
- Department of Periodontology, University of Florida, Gainesville, FL 32610, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
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Ecto-5'-nucleotidase (CD73) regulates host inflammatory responses and exacerbates murine salmonellosis. Sci Rep 2014; 4:4486. [PMID: 24670982 PMCID: PMC3967249 DOI: 10.1038/srep04486] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 03/10/2014] [Indexed: 01/13/2023] Open
Abstract
Food-borne Salmonella spp., are a major cause of hospitalization and death. Adenosine, an important immune regulator of inflammation, limits tissue damage during infection. CD39 (nucleoside triphosphate dephosphorylase) combined with ecto-5′-nucleotidase (CD73) metabolizes ATP to adenosine. We studied the expressions of CD39 and CD73 in tissues, and T helper cells in mice after Salmonella infection and evaluated the role of CD73 in regulating immune responses and bacterial clearance in wild-type and CD73-deficient (CD73−/−) mice. Both CD39 and CD73 transcript levels declined in the infected wild-type mice. Compared to wild-type mice, tissues from infected CD73−/− mice had significantly higher expression of pro-inflammatory cytokines and reduced anti-inflammatory responses. CD73−/− mice were more resistant to infection and had a greater inflammatory responses and a significantly lower bacterial load in the liver compared to wild-type mice. Thus, CD73 expression attenuates inflammation during murine Salmonellosis and impairs immunity, leading to increased bacterial colonization and prolonged infection.
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Abstract
Klebsiella pneumoniae liver abscess (KPLA) is prevalent in East Asia. Liver abscess can develop after translocation of K. pneumoniae from a patient's bowel into the liver via the portal circulation. TREM-1 (triggering receptor expressed on myeloid cells 1) amplifies inflammatory signaling during infection, but its role in KPLA is poorly understood. We used an animal study to characterize the role of TREM-1 in KPLA. We compared survival rates, bacterial burdens in tissues, inflammatory cytokine levels, and histology findings between wild-type and Trem-1 knockout (KO) mice after oral inoculation of capsular type K1 K. pneumoniae. Translocation of K. pneumoniae to mesenteric lymph nodes and liver was examined, and intestinal permeability, antimicrobial peptide expression, and the clearance of K. pneumoniae in the small intestine were determined. In the absence of TREM-1, KPLA model mice showed increased K. pneumoniae dissemination, enhanced liver and systemic inflammation, and reduced survival. Impaired bacterial clearance in the small intestine causes enhanced K. pneumoniae translocation, which renders Trem-1 KO mice more susceptible to K. pneumoniae oral infection. In conclusion, TREM-1-mediated bacterial clearance in the small intestine is an important immune response against K. pneumoniae. TREM-1 deficiency enhances K. pneumoniae translocation in the small intestine and increases mortality rates in mice with KPLA.
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Chen L, Zhang Z, Barletta KE, Burdick MD, Mehrad B. Heterogeneity of lung mononuclear phagocytes during pneumonia: contribution of chemokine receptors. Am J Physiol Lung Cell Mol Physiol 2013; 305:L702-11. [PMID: 24056971 DOI: 10.1152/ajplung.00194.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Bacterial pneumonia is a common and dangerous illness. Mononuclear phagocytes, which comprise monocyte, resident and recruited macrophage, and dendritic cell subsets, are critical to antimicrobial defenses, but the dynamics of their recruitment to the lungs in pneumonia is not established. We hypothesized that chemokine-mediated traffic of mononuclear phagocytes is important in defense against bacterial pneumonia. In a mouse model of Klebsiella pneumonia, circulating Ly6C(hi) and, to a lesser extent, Ly6C(lo) monocytes expanded in parallel with accumulation of inflammatory macrophages and CD11b(hi) dendritic cells and plasmacytoid dendritic cells in the lungs, whereas numbers of alveolar macrophages remained constant. CCR2 was expressed by Ly6C(hi) monocytes, recruited macrophages, and airway dendritic cells; CCR6 was prominently expressed by airway dendritic cells; and CX3CR1 was ubiquitously expressed by blood monocytes and lung CD11b(hi) dendritic cells during infection. CCR2-deficient, but not CCL2-, CX3CR1-, or CCR6-deficient animals exhibited worse outcomes of infection. The absence of CCR2 had no detectable effect on neutrophils but resulted in reduction of all subsets of lung mononuclear phagocytes in the lungs, including alveolar macrophages and airway and plasmacytoid dendritic cells. In addition, absence of CCR2 skewed the phenotype of lung mononuclear phagocytes, abrogating the appearance of M1 macrophages and TNF-producing dendritic cells in the lungs. Taken together, these data define the dynamics of mononuclear phagocytes during pneumonia.
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Affiliation(s)
- Jordi Rello
- Critical Care Department, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institute of Research, CIBERES, Universitat Autonoma de Barcelona, Barcelona, Spain
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35
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Branzk N, Papayannopoulos V. Molecular mechanisms regulating NETosis in infection and disease. Semin Immunopathol 2013; 35:513-30. [PMID: 23732507 PMCID: PMC3685711 DOI: 10.1007/s00281-013-0384-6] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 05/17/2013] [Indexed: 12/17/2022]
Abstract
Neutrophils are the foot soldiers of the immune system. They home in to the site of infection and kill pathogens by phagocytosis, degranulation, and the release of web-like structures called neutrophil extracellular traps (NETs) that trap and kill a variety of microbes. NETs have been shown to play a multitude of additional roles in immunity but have also been implicated in inflammatory and autoimmune disease. Here, we discuss the role of NETs in these various contexts with a particular emphasis on the molecular mechanisms that regulate NET release and clearance. We highlight the comprehensive concepts and explore the important open questions in the field.
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Affiliation(s)
- Nora Branzk
- Division of Molecular Immunology, Medical Research Council National Institute for Medical Research, Mill Hill, London, UK
| | - Venizelos Papayannopoulos
- Division of Molecular Immunology, Medical Research Council National Institute for Medical Research, Mill Hill, London, UK
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36
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Cheng OZ, Palaniyar N. NET balancing: a problem in inflammatory lung diseases. Front Immunol 2013; 4:1. [PMID: 23355837 PMCID: PMC3553399 DOI: 10.3389/fimmu.2013.00001] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/01/2013] [Indexed: 12/12/2022] Open
Abstract
Neutrophil extracellular traps (NETs) are beneficial antimicrobial defense structures that can help fight against invading pathogens in the host. However, recent studies reveal that NETs exert adverse effects in a number of diseases including those of the lung. Many inflammatory lung diseases are characterized with a massive influx of neutrophils into the airways. Neutrophils contribute to the pathology of these diseases. To date, NETs have been identified in the lungs of cystic fibrosis (CF), acute lung injury (ALI), allergic asthma, and lungs infected with bacteria, virus, or fungi. These microbes and several host factors can stimulate NET formation, or NETosis. Different forms of NETosis have been identified and are dependent on varying types of stimuli. All of these pathways however appear to result in the formation of NETs that contain DNA, modified extracellular histones, proteases, and cytotoxic enzymes. Some of the NET components are immunogenic and damaging to host tissue. Innate immune collectins, such as pulmonary surfactant protein D (SP-D), bind NETs, and enhance the clearance of dying cells and DNA by alveolar macrophages. In many inflammatory lung diseases, bronchoalveolar SP-D levels are altered and its deficiency results in the accumulation of DNA in the lungs. Some of the other therapeutic molecules under consideration for treating NET-related diseases include DNases, antiproteases, myeloperoxidase (MPO) inhibitors, peptidylarginine deiminase-4 inhibitors, and anti-histone antibodies. NETs could provide important biological advantage for the host to fight against certain microbial infections. However, too much of a good thing can be a bad thing. Maintaining the right balance of NET formation and reducing the amount of NETs that accumulate in tissues are essential for harnessing the power of NETs with minimal damage to the hosts.
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Affiliation(s)
- Olivia Z Cheng
- Program in Physiology and Experimental Medicine, Lung Innate Immunity Research Laboratory, SickKids Research Institute Toronto, ON, Canada ; Department of Laboratory Medicine and Pathobiology, University of Toronto Toronto, ON, Canada
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37
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Quinton LJ. Evaluating the NET influence of inflammation on pneumonia biology. Am J Respir Crit Care Med 2013; 186:943-4. [PMID: 23155213 DOI: 10.1164/rccm.201209-1702ed] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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