Altered expression of epithelial junctional proteins in atopic asthma: possible role in inflammation

• Published in: Canadian journal of physiology and pharmacology Vol. 86; no. 3; pp. 105 - 112
• Main Authors: de Boer, W.I, Sharma, H.S, Baelemans, S.M.I, Hoogsteden, H.C, Lambrecht, B.N, Braunstahl, G.J
• Format: Journal Article
• Language: English
• Published: Ottawa, ON National Research Council of Canada 01.03.2008; NRC Research Press; Canadian Science Publishing NRC Research Press
• Subjects: adhesion molecules; adhésion molécules; alpha Catenin - biosynthesis; Asthma; Asthma - metabolism; Asthma - pathology; asthme; beta Catenin - biosynthesis; Biological and medical sciences; biopsie; biopsy; Bronchi - chemistry; Bronchi - pathology; Cadherins - biosynthesis; catenins; caténines; Cell Adhesion Molecules - biosynthesis; Cell junctions; Eosinophils - chemistry; Eosinophils - pathology; Epithelial Attachment - chemistry; Epithelial Attachment - pathology; Epithelial Cells - chemistry; Epithelial Cells - pathology; epithelium; Fundamental and applied biological sciences. Psychology; Gene expression; Genetic aspects; Humans; Immunohistochemistry; Inflammation - metabolism; Inflammation - pathology; Inflammatory diseases; Intercellular Junctions - chemistry; Intercellular Junctions - pathology; Junctional complexes (Epithelium); MEDICIN; MEDICINE; Membrane Proteins - biosynthesis; Mucous Membrane - chemistry; Mucous Membrane - pathology; Phosphoproteins - biosynthesis; Physiological aspects; Proteins; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Zonula Occludens-1 Protein; épithélium; Netherlands; Allergy; Immunopathology; Lung disease; Respiratory disease; Inflammation; Epithelium; Gene expression; Adhesion; Asthma; Atopy; Vertebrata; Mammalia; Bronchus disease; Obstructive pulmonary disease; Catenin
• DOI: 10.1139/Y08-004
• ISSN: 0008-4212; 1205-7541

Epithelial cells form a tight barrier against environmental stimuli via tight junctions (TJs) and adherence junctions (AJs). Defects in TJ and AJ proteins may cause changes in epithelial morphology and integrity and potentially lead to faster trafficking of inflammatory cells through the epithelium. Bronchial epithelial fragility has been reported in asthmatic patients, but little is known about the expression of TJ and AJ proteins in asthma. We studied epithelial expression of zonula occludens-1 (ZO-1) and AJ proteins E-cadherin, α-catenin, and β-catenin in bronchial biopsies from nonatopic nonasthmatic (healthy) subjects (n = 14), and stable atopic asthmatic subjects (n = 22) at baseline conditions. Immunostaining for these proteins was semi-quantified for separate cellular compartments. E-cadherin, α-catenin and β-catenin were present in the cellular membrane and less in the cytoplasm. Only β-catenin was present in the nucleus in agreement with its potential function as transcription factor. ZO-1 was present in the apicolateral membrane of superficial cells. α-Catenin expression was significantly lower in subjects with asthma than without and correlated inversely with numbers of eosinophils within the epithelium. ZO-1 and E-cadherin expression were significantly lower in asthmatic than in nonasthmatic subjects. Expression of β-catenin was not different. Our results suggest that the lower epithelial α-catenin, E-cadherin and (or) ZO-1 expression in patients with atopic asthma contributes to a defective airway epithelial barrier and a higher influx of eosinophils in the epithelium.