Effects of Quorum Sensing Systems on Regulatory T Cells in Catheter-Related Pseudomonas aeruginosa Biofilm Infection Rat Models.

Lei Feng,Qingqing Xiang,Qi Lu,Qing Ai,Yunhui Zhang,Zhengli Wang

doi:10.1155/2016/4012912

Lei Feng, Qingqing Xiang + Show 4 more

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https://doi.org/10.1155/2016/4012912

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Abstract

Background. Quorum sensing (QS) systems play an important role in modulating biofilm formation. Recent studies have found that the QS molecules had complex effects on the host immune systems. In addition, regulatory T cells (Tregs), known as important negative regulators in the immune system, have been found upregulated in multiple chronic infections. Therefore, the QS systems were hypothesized to be involved in modulating Tregs in biofilm-associated infections. Object. To explore the effects of QS systems on Tregs in catheter-related Pseudomonas aeruginosa biofilm infection rat models. Method. Catheter-related Pseudomonas aeruginosa biofilm infection rat models were established; the bacterial clearance rates, total cell counts in bronchoalveolar lavage (BAL) fluid, pathological changes of lungs, and the levels of Foxp3, TGF-β1, and IL-10 in PAO1 strain group were examined and compared with the QS-mutant ΔlasRΔrhlR and ΔlasIΔrhlI groups. Results. In PAO1 group, the bacterial clearance rates were lower, total cell counts were higher, pathological changes were severer, and the levels of Foxp3, TGF-β1, and IL-10 were significantly higher compared with QS-mutant groups (p < 0.05). No significant difference was observed between the two QS-mutant groups (p > 0.05). Conclusion. QS systems can trigger host immune system, accompanied with the upregulation of Tregs.

Highlights

Cystic fibrosis (CF) is a congenital, recessively inherited disorder, associated with decreased lung function, aggravated pulmonary symptoms, and prolonged duration [1]
Two QSmutant ΔlasRΔrhlR and ΔlasIΔrhlI groups were significantly lower compared with PAO1 strain (p < 0.05), indicating that the bacteria were significantly eradicated when Quorum sensing (QS) systems were absent
The relationship between Tregs and P. aeruginosa QS systems was investigated in the context of bacterial clearance rates, pathological changes, total cell counts in bronchoalveolar lavage (BAL) fluid, and Treg-related cytokines

Summary

Introduction

Cystic fibrosis (CF) is a congenital, recessively inherited disorder, associated with decreased lung function, aggravated pulmonary symptoms, and prolonged duration [1]. The airways of patients with CF are chronically colonized with diverse bacterial, fungal, and viral taxa. Among these microorganisms, Pseudomonas aeruginosa (P. aeruginosa) are the most commonly isolated organisms [2]. The QS systems were hypothesized to be involved in modulating Tregs in biofilm-associated infections. To explore the effects of QS systems on Tregs in catheter-related Pseudomonas aeruginosa biofilm infection rat models. Catheter-related Pseudomonas aeruginosa biofilm infection rat models were established; the bacterial clearance rates, total cell counts in bronchoalveolar lavage (BAL) fluid, pathological changes of lungs, and the levels of Foxp, TGF-β1, and IL-10 in PAO1 strain group were examined and compared with the QS-mutant ΔlasRΔrhlR and ΔlasIΔrhlI groups. QS systems can trigger host immune system, accompanied with the upregulation of Tregs

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Conclusion