title: Expression of PPARγ and paraoxonase 2 correlated with Pseudomonas aeruginosa infection in cystic fibrosis.
abstract: The Pseudomonas aeruginosa quorum sensing signal molecule N-3-oxododecanoyl-l-homoserine lactone (3OC(12)HSL) can inhibit function of the mammalian anti-inflammatory transcription factor peroxisome proliferator activated receptor (PPAR)γ, and can be degraded by human paraoxonase (PON)2. Because 3OC(12)HSL is detected in lungs of cystic fibrosis (CF) patients infected with P. aeruginosa, we investigated the relationship between P. aeruginosa infection and gene expression of PPARγ and PON2 in bronchoalveolar lavage fluid (BALF) of children with CF. Total RNA was extracted from cell pellets of BALF from 43 children aged 6 months-5 years and analyzed by reverse transcription-quantitative real time PCR for gene expression of PPARγ, PON2, and P. aeruginosa lasI, the 3OC(12)HSL synthase. Patients with culture-confirmed P. aeruginosa infection had significantly lower gene expression of PPARγ and PON2 than patients without P. aeruginosa infection. All samples that were culture-positive for P. aeruginosa were also positive for lasI expression. There was no significant difference in PPARγ or PON2 expression between patients without culture-detectable infection and those with non-Pseudomonal bacterial infection, so reduced expression was specifically associated with P. aeruginosa infection. Expression of both PPARγ and PON2 was inversely correlated with neutrophil counts in BALF, but showed no correlation with other variables evaluated. Thus, lower PPARγ and PON2 gene expression in the BALF of children with CF is associated specifically with P. aeruginosa infection and neutrophilia. We cannot differentiate whether this is a cause or the effect of P. aeruginosa infection, but propose that the level of expression of these genes may be a marker for susceptibility to early acquisition of P. aeruginosa in children with CF.
authors.affiliation: Menzies Research Institute, Hobart, Tasmania, Australia.
authors.forename: Phoebe E
authors.initials: PE
authors.lastname: Griffin
authors.forename: Louise F
authors.initials: LF
authors.lastname: Roddam
authors.forename: Yvonne C
authors.initials: YC
authors.lastname: Belessis
authors.forename: Roxanne
authors.initials: R
authors.lastname: Strachan
authors.forename: Sean
authors.initials: S
authors.lastname: Beggs
authors.forename: Adam
authors.initials: A
authors.lastname: Jaffe
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Cooley
mesh_terms: D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications* / Q000378:metabolism; D017931:DNA Primers; D005260:Female; D015870:Gene Expression; D006801:Humans; D007223:Infant; D008297:Male; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D011552:Pseudomonas Infections / Q000150:complications* / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D047495:PPAR gamma; D043303:Aryldialkylphosphatase; C468411:PON2 protein, human