title: The endogenous cannabinoid anandamide increases human airway epithelial cell permeability through an arachidonic acid metabolite.
abstract: Injury to the bronchial epithelium in respiratory diseases such as asthma and COPD results in the loss of barrier function and an elevated sensitivity to environmental insults. An increased release of the endogenous cannabinoid, anandamide in response to inhalation of allergen in asthmatic patients has been reported. The aim of this study was, therefore, to determine the effects of endocannabinoids on bronchial epithelial cell permeability and to investigate the mechanisms involved. Calu-3 human bronchial epithelial cells were cultured at air-liquid interface to allow development of tight junctions. Changes in Transepithelial Electrical Resistance (TEER), a reflection of epithelial permeability, were measured at various time points post-treatment, and expression of the tight junction proteins, occludin and ZO-1, were determined using Western immunoblotting. Anandamide produced a significant reduction in TEER, which was unaffected by cannabinoid receptor antagonists, but attenuated by URB597, an inhibitor of fatty acid amide hydrolase, and by a combination of cyclooxygenase (COX) and lipoxygenase (LOX) blockade. The anandamide metabolite, arachidonic acid, showed similar TEER decrease that was also prevented in the presence of COX and LOX inhibitor. Expression of occludin and ZO-1 were also reduced by anandamide. These findings indicate a pro-inflammatory-like effect of anandamide on bronchial epithelial permeability, mediated by cyclooxygenase and lipoxygenase metabolites, and suggest that inhibition of anandamide degradation might provide a novel approach to treat airway inflammation.
authors.affiliation: School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom. Electronic address: mbxvcsh@nottingham.ac.uk.
authors.forename: V C M
authors.initials: VC
authors.lastname: Shang
authors.affiliation: School of Graduate Entry Medicine and Health, Royal Derby Hospital, University of Nottingham, DE22 3DT, United Kingdom.
authors.forename: S E
authors.initials: SE
authors.lastname: O'Sullivan
authors.affiliation: School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
authors.forename: D A
authors.initials: DA
authors.lastname: Kendall
authors.affiliation: School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
authors.forename: R E
authors.initials: RE
authors.lastname: Roberts
mesh_terms: D001095:Arachidonic Acids / Q000378:metabolism*; D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D002460:Cell Line; D063388:Endocannabinoids / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D062793:Occludin / Q000378:metabolism; D010539:Permeability; D053284:Polyunsaturated Alkamides / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000378:metabolism*; D015398:Signal Transduction; D019108:Tight Junctions / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D001095:Arachidonic Acids; D063388:Endocannabinoids; D062793:Occludin; D053284:Polyunsaturated Alkamides; C569042:TJP1 protein, human; D014409:Tumor Necrosis Factor-alpha; D062826:Zonula Occludens-1 Protein; C078814:anandamide
keywords: Anandamide; Bronchial epithelium; Chronic airway inflammation; Endocannabinoid; Permeability; Tight junction