Mucoid Pseudomonas aeruginosa, TNF-alpha, and IL-1beta, but not IL-6, induce human beta-defensin-2 in respiratory epithelia.
Cultured lung epithelial cells release antibacterial activity upon contact with Pseudomonas aeruginosa (PA), which is impaired in cystic fibrosis (CF). In order to identify the factors responsible for killing PA by a biochemical approach, we purified antimicrobial activity from supernatants of the A549 lung epithelial cell line, previously stimulated with PA bacteria, by subsequent high performance liquid chromatography. NH(2)-terminal sequencing of a major bactericidal compound revealed it to be identical with human beta-defensin-2 (hBD-2). A mucoid phenotype of PA, but not two nonmucoid PA strains, high concentrations (> 10 microg/ml) of PA lipopolysaccharide, tumor necrosis factor alpha, and interleukin (IL)-1beta, but not IL-6, dose-dependently induced hBD-2 messenger RNA in cultured normal bronchial, tracheal, as well as normal and CF-derived nasal epithelial cells. Genomic analysis of hBD-2 revealed a promoter region containing several putative transcription factor binding sites, including nuclear factor (NF) kappaB, activator protein (AP)-1, AP-2, and NF-IL-6, known to be involved in the regulation of inflammatory responses. Thus, hBD-2 represents a major inducible antimicrobial factor released by airway epithelial cells either on contact with mucoid PA or by endogenously produced primary cytokines. Therefore, it might be important in lung infections caused by mucoid PA, including those seen in patients with CF.
Harder
J
J
Department of Dermatology and Otolaryngology, University of Kiel, Kiel, Germany.
Meyer-Hoffert
U
U
Teran
L M
LM
Schwichtenberg
L
L
Bartels
J
J
Maune
S
S
Schröder
J M
JM
D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D003550:Cystic Fibrosis / Q000276:immunology / Q000382:microbiology; D023082:Defensins; D004847:Epithelial Cells / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D007375:Interleukin-1 / Q000276:immunology*; D015850:Interleukin-6 / Q000276:immunology; D008168:Lung / Q000166:cytology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D011506:Proteins / Q000235:genetics* / Q000276:immunology / Q000494:pharmacology; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000276:immunology*; D011550:Pseudomonas aeruginosa; D012333:RNA, Messenger / Q000032:analysis; D020545:Respiratory Mucosa / Q000166:cytology / Q000276:immunology* / Q000382:microbiology; D012492:Salts; D014157:Transcription Factors / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
D023082:Defensins; D007375:Interleukin-1; D015850:Interleukin-6; D011506:Proteins; D012333:RNA, Messenger; D012492:Salts; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha