Background: Epithelial barrier dysfunction and increased permeability may contribute to antigen sensitization and disease progression in asthma. Claudin-18.1 is the only known lung-specific tight junction protein, but its contribution to airway barrier function or asthma is unclear.
Objectives: We sought to test the hypotheses that claudin-18 is a determinant of airway epithelial barrier function that is downregulated by IL-13 and that claudin-18 deficiency results in increased aeroantigen sensitization and airway hyperresponsiveness.
Methods: Claudin-18.1 mRNA levels were measured in airway epithelial brushings from healthy controls and patients with asthma. In patients with asthma, claudin-18 levels were compared with a three-gene-mean marker of T2 inflammation. Airway epithelial permeability changes due to claudin-18 deficiency were measured in 16HBE cells and claudin-18 null mice. The effect of IL-13 on claudin expression was determined in primary human airway epithelial cells and in mice. Airway hyperresponsiveness and serum IgE levels were compared in claudin-18 null and wild-type mice following aspergillus sensitization.
Results: Epithelial brushings from patients with asthma (n = 67) had significantly lower claudin-18 mRNA levels than did those from healthy controls (n = 42). Claudin-18 levels were lowest among T2-high patients with asthma. Loss of claudin-18 was sufficient to impair epithelial barrier function in 16HBE cells and in mouse airways. IL-13 decreased claudin-18 expression in primary human cells and in mice. Claudin-18 null mice had significantly higher serum IgE levels and increased airway responsiveness following intranasal aspergillus sensitization.
Conclusions: These data support the hypothesis that claudin-18 is an essential contributor to the airway epithelial barrier to aeroantigens. Furthermore, T2 inflammation suppresses claudin-18 expression, potentially promoting sensitization and airway hyperresponsiveness.
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http://dx.doi.org/10.1016/j.jaci.2016.02.035 | DOI Listing |
Expert Rev Respir Med
January 2025
School of Medicine and Public Health, University of Wisconsin Madison, Madison, WI, USA.
Introduction: In genetically predisposed individuals, exposure to aeroallergens and infections from RNA viruses shape epithelial barrier function, leading to Allergic Asthma (AA). Here, activated pattern recognition receptors (PRRs) in lower airway sentinel cells signal epithelial injury-repair pathways leading to cell-state changes [epithelial mesenchymal plasticity (EMP)], barrier disruption and sensitization.
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mBio
December 2024
Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA.
Unlabelled: Respiratory epithelial cells can survive direct infection by influenza viruses, and the long-term consequences of that infection have been characterized in a subset of proximal airway cell types. The impact on the cells that survive viral infection in the distal lung epithelia, however, is much less well-characterized. Utilizing a Cre-expressing influenza B virus (IBV) and a lox-stop-lox tdTomato reporter mouse model, we identified that alveolar type 2 (AT2) pneumocytes, a progenitor cell type in the distal lung, can survive viral infection.
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February 2025
Specialist Allergy and Clinical Immunology, Rhinology Section, Royal National ENT and Eastman Dental Hospitals, University College London Hospitals NHS Foundation Trust, London, UK.
Purpose Of Review: To evaluate the role of neuroimmune signalling pathways in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP).
Recent Findings: The sinonasal mucosa is densely infiltrated by immune cells and neuronal structures that share an intimate spatial relationship within tissue compartments. Together, such neuroimmune units play a critical role in airway defence and homeostatic function.
Int J Biol Sci
January 2025
Division of Science Education, Kangwon National University, 24341, Republic of Korea.
Intricate crosstalk among various lung cell types is crucial for orchestrating diverse physiological processes. Traditional two-dimensional and recent three-dimensional (3D) assay platforms fail to precisely replicate these complex communications. Many lung models do not effectively reflect the multicellular complexity of lung tissue.
View Article and Find Full Text PDFTissue Cell
December 2024
State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, School of Life Sciences, School of Public Health, Xiamen University, Xiamen, China; National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Collaborative Innovation Center of Biologic Products, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, China. Electronic address:
Chronic obstructive pulmonary disease (COPD) poses global health challenges owing to limited treatment options and high rates of morbidity and mortality. Airway organoids have recently become a valuable resource for the investigation of respiratory diseases. However, limited access to clinical tissue samples hinders the use of airway organoids to study COPD.
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