Abstract
Antimicrobial proteins and peptides (AMPs) are a central component of the antibacterial activity of airway epithelial cells. It has been proposed that a decrease in antibacterial lung defense contributes to an increased susceptibility to microbial infection in smokers and patients with chronic obstructive pulmonary disease (COPD). However, whether reduced AMP expression in the epithelium contributes to this lower defense is largely unknown. We investigated the bacterial killing activity and expression of AMPs by air-liquid interface-cultured primary bronchial epithelial cells from COPD patients and non-COPD (ex-)smokers that were stimulated with nontypeable Haemophilus influenzae (NTHi). In addition, the effect of cigarette smoke on AMP expression and the activation of signaling pathways was determined. COPD cell cultures displayed reduced antibacterial activity, whereas smoke exposure suppressed the NTHi-induced expression of AMPs and further increased IL-8 expression in COPD and non-COPD cultures. Moreover, smoke exposure impaired NTHi-induced activation of NF-κB, but not MAP-kinase signaling. Our findings demonstrate that the antibacterial activity of cultured airway epithelial cells induced by acute bacterial exposure was reduced in COPD and suppressed by cigarette smoke, whereas inflammatory responses persisted. These findings help to explain the imbalance between protective antibacterial and destructive inflammatory innate immune responses in COPD.
Original language | English |
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Pages (from-to) | 359-374 |
Number of pages | 16 |
Journal | Journal of Innate Immunity |
Volume | 9 |
Issue number | 4 |
Early online date | 8 Feb 2017 |
DOIs | |
Publication status | Published - 1 Jul 2017 |
Externally published | Yes |
Keywords
- Journal Article
- Host defense
- Antimicrobial peptides
- Chronic obstructive pulmonary disease
- Epithelium
- Cigarette smoke
- Signal Transduction
- Immunomodulation
- Humans
- Cells, Cultured
- Haemophilus Infections/immunology
- Haemophilus influenzae/immunology
- Immunity
- Cigarette Smoking/adverse effects
- Pulmonary Disease, Chronic Obstructive/immunology
- Interleukin-8/metabolism
- Respiratory Mucosa/immunology
- Antimicrobial Cationic Peptides/genetics
- Bacteriolysis
- NF-kappa B/metabolism