Dataset Information

Neutrophil extracellular traps are present in the airways of ENaC-overexpressing mice with cystic fibrosis-like lung disease.

ABSTRACT:

Background

Neutrophils are key components of the exacerbated inflammation and tissue damage in cystic fibrosis (CF) airways. Neutrophil extracellular traps (NETs) trap and kill extracellular pathogens. While NETs are abundant in the airways of CF patients and have been hypothesized to contribute to lung damage in CF, the in vivo role of NETs remains controversial, partially due to lack of appropriate animal models. The goal of this study was to detect NETs and to further characterize neutrophil-mediated inflammation in the airways of mice overexpressing the epithelial sodium channel (?ENaC-Tg mice on C57BL/6 background) in their lung with CF-like airway disease, in the absence of any apparent bacterial infections.

Methods

Histology scoring of lung tissues, flow cytometry, multiplex ELISA, immunohistochemistry and immunofluorescence were used to characterize NETs and the airway environment in uninfected, ?ENaC-Tg mice at 6 and 8?weeks of age, the most chronic time points so far studied in this model.

Results

Excessive neutrophilic infiltration characterized the lungs of uninfected, ?ENaC-Tg mice at 6 and 8?weeks of age. The bronchoalveolar lavage fluid (BALF) of ?ENaC-Tg mice contains increased levels of CF-associated cytokines and chemokines: KC, MIP-1?/?, MCP-1, G-CSF, IL-5, and IL-6. The BALF of ?ENaC-Tg mice contain MPO-DNA complexes, indicative of the presence of NETs. Immunofluorescence and flow cytometry of BALF neutrophils and lung tissues demonstrated increased histone citrullination, a NET-specific marker, in ?ENaC-Tg mice.

Conclusions

NETs are detected in the airways of ?ENaC-Tg mice, in the absence of bacterial infections. These data demonstrate the usefulness of the ?ENaC-Tg mouse to serve as a model for studying the role of NETs in chronic CF airway inflammation.

SUBMITTER: Tucker SL

PROVIDER: S-EPMC7819174 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Neutrophil extracellular traps are present in the airways of ENaC-overexpressing mice with cystic fibrosis-like lung disease.

Tucker Samantha L SL Sarr Demba D Rada Balázs B

BMC immunology 20210121 1

<h4>Background</h4>Neutrophils are key components of the exacerbated inflammation and tissue damage in cystic fibrosis (CF) airways. Neutrophil extracellular traps (NETs) trap and kill extracellular pathogens. While NETs are abundant in the airways of CF patients and have been hypothesized to contribute to lung damage in CF, the in vivo role of NETs remains controversial, partially due to lack of appropriate animal models. The goal of this study was to detect NETs and to further characterize neu ...[more]

PMID: 33478382

Similar Datasets

Project description:Cystic Fibrosis (CF) is a devastating genetic disease characterised primarily by unrelenting lung inflammation and infection resulting in premature death and significant morbidity. Neutrophil Extracellular Traps (NETs) are possibly key to inflammation in the disease. This review aims to draw together existing research investigating NETs in the context of a dysfunctional innate immune system in CF.NETs have a limited anti-microbial role in CF and studies have shown they are present in higher numbers in CF airways and their protein constituents correlate with lung function decline. Innate immune system cells express CFTR and myeloid-specific CFTR KO mice have greater neutrophil recruitment and higher pro-inflammatory cytokine production to both sterile and bacterial inflammatory challenges. CFTR KO neutrophils have impaired anti-microbial capacity and intrinsic abnormalities in the pH of their cytoplasm, abnormal protein trafficking, increased neutrophil elastase and myeloperoxidase function, and decreased hypochlorite concentrations in their phagolysosomes. Furthermore, neutrophils from CF patients have less intrinsic apoptosis and may be therefore more likely to make NETs. CFTR KO macrophages have high intraphagolysosomal pH and increased toll-like receptor 4 on their cell surface membranes, which inhibit their anti-microbial capacity and render them hyper-responsive to inflammatory stimuli, respectively. Pharmacological treatments for CF target these intrinsic abnormalities of immune dysfunction. Emerging evidence suggests that the absence of CFTR from neutrophils affects NETosis and the interaction of NETs with macrophages.Current evidence suggests that NETs contribute to inflammation and lung destruction rather than working effectively in their anti-microbial capacity. Further studies focussing on the pro-inflammatory nature of NET constituents are required to identify the exact mechanistic role of NETs in CF and potential therapeutic interventions.

Project description:Neutrophils, the first line of the host's defense, use a variety of antimicrobial mechanisms to fight invading pathogens. One of the most crucial is the production of neutrophil extracellular traps (NETs) in the process called NETosis. The unique structure of NETs effectively inhibits the spread of pathogens and ensures their exposure to a high concentration of NET-embedded antimicrobial compounds. NETosis strategy is often used by the host to defend against fungal infection caused by Candida albicans. In immunocompromised patients, this microorganism is responsible for developing systemic fungal infections (candidiasis). This is correlated with the use of a vast array of virulence factors, leading to the acquisition of specific resistance to host defense factors and available drug therapies. One of the most important features favoring the development of drug resistance is a C. albicans ability to form biofilms that protect fungal cells mainly through the production of an extracellular matrix (ECM). Among the main ECM-building macromolecules extracellular nucleic acids have been identified and their role is probably associated with the stbilization of the biofilm structure. The complex interactions of immune cells with the thick ECM layer, comprising the first line of contact between these cells and the biofilm structure, are still poorly understood. Therefore, the current studies aimed to assess the release of extracellular nucleic acids by C. albicans strains at different stages of biofilm formation, and to determine the role of these molecules in triggering the NETosis. We showed for the first time that fungal nucleic acids, purified directly from mature C. albicans biofilm structure or obtained from the whole fungal cells, have the potential to induce NET release in vitro. In this study, we considered the involvement of TLR8 and TLR9 in NETosis activation. We showed that DNA and RNA molecules initiated the production of reactive oxygen species (ROS) by activation of the NADPH oxidase complex, essential for ROS-dependent NETosis. Furthermore, analysis of the cell migration showed that the nucleic acids located in the extracellular space surrounding the biofilm may be also effective chemotactic factors, driving the dynamic migration of human neutrophils to the site of ongoing fungal infection.

Dataset Information

Neutrophil extracellular traps are present in the airways of ENaC-overexpressing mice with cystic fibrosis-like lung disease.

Background

Methods

Results

Conclusions

Publications

Neutrophil extracellular traps are present in the airways of ENaC-overexpressing mice with cystic fibrosis-like lung disease.

Similar Datasets

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