Microarray analysis reveals induction of lipoprotein genes in mucoid Pseudomonas aeruginosa: implications for inflammation in cystic fibrosis.
The main cause of the high morbidity and mortality of cystic fibrosis (CF) is the progressive lung inflammation associated with Pseudomonas aeruginosa colonization. During the course of chronic CF infections, P. aeruginosa undergoes a conversion to a mucoid phenotype. The emergence of mucoid P. aeruginosa in CF is associated with increased inflammation, respiratory decline, and a poor prognosis. Here we show, by the use of microarray analysis, that upon P. aeruginosa conversion to mucoidy, there is a massive and preferential induction of genes encoding bacterial lipoproteins. Bacterial lipoproteins are potent agonists of Toll-like receptor 2 (TLR2) signaling. The expression of TLR2 in human respiratory epithelial cells was ascertained by Western blot analysis. Human respiratory epithelial cells responded in a TLR2-dependent manner to bacterial lipopeptides derived from Pseudomonas lipoproteins induced in mucoid strains. The TLR2 proinflammatory response was further augmented in CF cells. Thus, the excessive inflammation in CF is the result of a global induction in mucoid P. aeruginosa of lipoproteins that act as proinflammatory toxins (here termed lipotoxins) superimposed on the hyperexcitability of CF cells. Blocking the signaling cascade responding to bacterial lipotoxins may provide therapeutic benefits for CF patients.
Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, 915 Camino de Salud NE, Albuquerque, NM 87131, USA.
Aaron M
AM
Firoved
Wojciech
W
Ornatowski
Vojo
V
Deretic
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001980:Bronchi / Q000166:cytology; D002460:Cell Line; D002478:Cells, Cultured; D003550:Cystic Fibrosis / Q000382:microbiology / Q000503:physiopathology*; D004847:Epithelial Cells / Q000382:microbiology; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007249:Inflammation / Q000382:microbiology / Q000503:physiopathology*; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011552:Pseudomonas Infections / Q000382:microbiology / Q000503:physiopathology; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors; D014774:Virulence
D001426:Bacterial Proteins; D008074:Lipoproteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors