Beta defensin-2 is reduced in central but not in distal airways of smoker COPD patients

• Published in: PloS one Vol. 7; no. 3; p. e33601
• Main Authors: Pace, Elisabetta, Ferraro, Maria, Minervini, Marta Ida, Vitulo, Patrizio, Pipitone, Loredana, Chiappara, Giuseppina, Siena, Liboria, Montalbano, Angela Marina, Johnson, Malcolm, Gjomarkaj, Mark
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16-03-2012; Public Library of Science (PLoS)
• Subjects: Activation; Aged; Asthma; Bacteria; Bacterial infections; Base Sequence; beta-Defensins - genetics; beta-Defensins - metabolism; Biology; Bronchi - metabolism; Bronchi - pathology; Case-Control Studies; Cell Line; Chemokines; Chronic obstructive lung disease; Chronic obstructive pulmonary disease; Cigarette smoke; Cigarettes; Colonization; Councils; Cytokines; Dendritic cells; Down-Regulation; Epithelial cells; Epithelial Cells - metabolism; Epithelial Cells - pathology; Female; Gene expression; Genes; Humans; Immunity; Immunohistochemistry; Immunology; Innate immunity; Interleukin 1; Lung diseases; Male; Medicine; Middle Aged; Multivariate analysis; NF-κB protein; Obstructive lung disease; Patients; Pulmonary Disease, Chronic Obstructive - etiology; Pulmonary Disease, Chronic Obstructive - genetics; Pulmonary Disease, Chronic Obstructive - metabolism; Pulmonary Disease, Chronic Obstructive - pathology; R&D; Real-Time Polymerase Chain Reaction; Receptors; Research & development; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; Smoke; Smokers; Smoking; Smoking - adverse effects; Smoking - genetics; Smoking - metabolism; Surgery; TLR4 protein; Toll-Like Receptor 4 - metabolism; Toll-like receptors; Italy
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0033601

Altered pulmonary defenses in chronic obstructive pulmonary disease (COPD) may promote distal airways bacterial colonization. The expression/activation of Toll Like receptors (TLR) and beta 2 defensin (HBD2) release by epithelial cells crucially affect pulmonary defence mechanisms.
The epithelial expression of TLR4 and of HBD2 was assessed in surgical specimens from current smokers COPD (s-COPD; n = 17), ex-smokers COPD (ex-s-COPD; n = 8), smokers without COPD (S; n = 12), and from non-smoker non-COPD subjects (C; n = 13).
In distal airways, s-COPD highly expressed TLR4 and HBD2. In central airways, S and s-COPD showed increased TLR4 expression. Lower HBD2 expression was observed in central airways of s-COPD when compared to S and to ex-s-COPD. s-COPD had a reduced HBD2 gene expression as demonstrated by real-time PCR on micro-dissected bronchial epithelial cells. Furthermore, HBD2 expression positively correlated with FEV1/FVC ratio and inversely correlated with the cigarette smoke exposure. In a bronchial epithelial cell line (16 HBE) IL-1β significantly induced the HBD2 mRNA expression and cigarette smoke extracts significantly counteracted this IL-1 mediated effect reducing both the activation of NFkB pathway and the interaction between NFkB and HBD2 promoter.
This study provides new insights on the possible mechanisms involved in the alteration of innate immunity mechanisms in COPD.