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In vivo imaging of the lung inflammatory response to Pseudomonas aeruginosa and its modulation by azithromycin.

Stellari F, Bergamini G, Sandri A, Donofrio G, Sorio C, Ruscitti F, Villetti G, Assael BM, Melotti P, Lleo MM - J Transl Med (2015)

Bottom Line: In vivo imaging indicated that VR1 strain, releasing in its culture supernatant metalloproteases and other virulence factors, induced lung inflammation while the VR2 strain presented with a severely reduced pro-inflammatory activity.The animal model was also used to test the anti-inflammatory activity of azithromycin (AZM), an antibiotic with demonstrated inhibitory effect on the synthesis of bacterial exoproducts.The data presented indicate that the model is suitable to functionally monitor in real time the lung inflammatory response facilitating the identification of bacterial factors with pro-inflammatory activity and the evaluation of the anti-inflammatory activity of old and new molecules for therapeutic use.

View Article: PubMed Central - PubMed

Affiliation: Pharmacology and Toxicology Department Corporate Pre-Clinical R&D, Chiesi Farmaceutici S.p.A. Parma, Largo Belloli, 11/A, 43122, Parma, Italy. fb.stellari@chiesi.com.

ABSTRACT

Background: Chronic inflammation of the airways is a central component in lung diseases and is frequently associated with bacterial infections. Monitoring the pro-inflammatory capability of bacterial virulence factors in vivo is challenging and usually requires invasive methods.

Methods: Lung inflammation was induced using the culture supernatants from two Pseudomonas aeruginosa clinical strains, VR1 and VR2, isolated from patients affected by cystic fibrosis and showing different phenotypes in terms of motility, colony characteristics and biofilm production as well as pyoverdine and pyocyanine release. More interesting, the strains differ also for the presence in supernatants of metalloproteases, a family of virulence factors with known pro-inflammatory activity. We have evaluated the benefit of using a mouse model, transiently expressing the luciferase reporter gene under the control of an heterologous IL-8 bovine promoter, to detect and monitoring lung inflammation.

Results: In vivo imaging indicated that VR1 strain, releasing in its culture supernatant metalloproteases and other virulence factors, induced lung inflammation while the VR2 strain presented with a severely reduced pro-inflammatory activity. The bioluminescence signal was detectable from 4 to 48 h after supernatant instillation. The animal model was also used to test the anti-inflammatory activity of azithromycin (AZM), an antibiotic with demonstrated inhibitory effect on the synthesis of bacterial exoproducts. The inflammation signal in mice was in fact significantly reduced when bacteria grew in the presence of a sub-lethal dose of AZM causing inhibition of the synthesis of metalloproteases and other bacterial elements. The in vivo data were further supported by quantification of immune cells and cytokine expression in mouse broncho-alveolar lavage samples.

Conclusions: This experimental animal model is based on the transient transduction of the bovine IL-8 promoter, a gene representing a major player during inflammation, essential for leukocytes recruitment to the inflamed tissue. It appears to be an appropriate molecular read-out for monitoring the activation of inflammatory pathways caused by bacterial virulence factors. The data presented indicate that the model is suitable to functionally monitor in real time the lung inflammatory response facilitating the identification of bacterial factors with pro-inflammatory activity and the evaluation of the anti-inflammatory activity of old and new molecules for therapeutic use.

No MeSH data available.


Related in: MedlinePlus

Phenotypic characteristics and virulence factors of the P. aeruginosa clinical strains.
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Fig1: Phenotypic characteristics and virulence factors of the P. aeruginosa clinical strains.

Mentions: Two P. aeruginosa strains, VR1 and VR2, were isolated from sputum samples of CF patients followed at the Cystic Fibrosis Center in Verona, Italy and were characterized for their differential expression of known virulence factors (data summarized in Fig. 1). Written informed consent was obtained from the subjects enrolled in the study and approved by the Institutional Review Board of Azienda Ospedaliera Universitaria Integrata (AOUI) Verona as project 1612.Fig. 1


In vivo imaging of the lung inflammatory response to Pseudomonas aeruginosa and its modulation by azithromycin.

Stellari F, Bergamini G, Sandri A, Donofrio G, Sorio C, Ruscitti F, Villetti G, Assael BM, Melotti P, Lleo MM - J Transl Med (2015)

Phenotypic characteristics and virulence factors of the P. aeruginosa clinical strains.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4522964&req=5

Fig1: Phenotypic characteristics and virulence factors of the P. aeruginosa clinical strains.
Mentions: Two P. aeruginosa strains, VR1 and VR2, were isolated from sputum samples of CF patients followed at the Cystic Fibrosis Center in Verona, Italy and were characterized for their differential expression of known virulence factors (data summarized in Fig. 1). Written informed consent was obtained from the subjects enrolled in the study and approved by the Institutional Review Board of Azienda Ospedaliera Universitaria Integrata (AOUI) Verona as project 1612.Fig. 1

Bottom Line: In vivo imaging indicated that VR1 strain, releasing in its culture supernatant metalloproteases and other virulence factors, induced lung inflammation while the VR2 strain presented with a severely reduced pro-inflammatory activity.The animal model was also used to test the anti-inflammatory activity of azithromycin (AZM), an antibiotic with demonstrated inhibitory effect on the synthesis of bacterial exoproducts.The data presented indicate that the model is suitable to functionally monitor in real time the lung inflammatory response facilitating the identification of bacterial factors with pro-inflammatory activity and the evaluation of the anti-inflammatory activity of old and new molecules for therapeutic use.

View Article: PubMed Central - PubMed

Affiliation: Pharmacology and Toxicology Department Corporate Pre-Clinical R&D, Chiesi Farmaceutici S.p.A. Parma, Largo Belloli, 11/A, 43122, Parma, Italy. fb.stellari@chiesi.com.

ABSTRACT

Background: Chronic inflammation of the airways is a central component in lung diseases and is frequently associated with bacterial infections. Monitoring the pro-inflammatory capability of bacterial virulence factors in vivo is challenging and usually requires invasive methods.

Methods: Lung inflammation was induced using the culture supernatants from two Pseudomonas aeruginosa clinical strains, VR1 and VR2, isolated from patients affected by cystic fibrosis and showing different phenotypes in terms of motility, colony characteristics and biofilm production as well as pyoverdine and pyocyanine release. More interesting, the strains differ also for the presence in supernatants of metalloproteases, a family of virulence factors with known pro-inflammatory activity. We have evaluated the benefit of using a mouse model, transiently expressing the luciferase reporter gene under the control of an heterologous IL-8 bovine promoter, to detect and monitoring lung inflammation.

Results: In vivo imaging indicated that VR1 strain, releasing in its culture supernatant metalloproteases and other virulence factors, induced lung inflammation while the VR2 strain presented with a severely reduced pro-inflammatory activity. The bioluminescence signal was detectable from 4 to 48 h after supernatant instillation. The animal model was also used to test the anti-inflammatory activity of azithromycin (AZM), an antibiotic with demonstrated inhibitory effect on the synthesis of bacterial exoproducts. The inflammation signal in mice was in fact significantly reduced when bacteria grew in the presence of a sub-lethal dose of AZM causing inhibition of the synthesis of metalloproteases and other bacterial elements. The in vivo data were further supported by quantification of immune cells and cytokine expression in mouse broncho-alveolar lavage samples.

Conclusions: This experimental animal model is based on the transient transduction of the bovine IL-8 promoter, a gene representing a major player during inflammation, essential for leukocytes recruitment to the inflamed tissue. It appears to be an appropriate molecular read-out for monitoring the activation of inflammatory pathways caused by bacterial virulence factors. The data presented indicate that the model is suitable to functionally monitor in real time the lung inflammatory response facilitating the identification of bacterial factors with pro-inflammatory activity and the evaluation of the anti-inflammatory activity of old and new molecules for therapeutic use.

No MeSH data available.


Related in: MedlinePlus