scholarly journals Tomatidine Inhibits Replication of Staphylococcus aureus Small-Colony Variants in Cystic Fibrosis Airway Epithelial Cells

2011 ◽  
Vol 55 (5) ◽  
pp. 1937-1945 ◽  
Author(s):  
Gabriel Mitchell ◽  
Mariza Gattuso ◽  
Gilles Grondin ◽  
Éric Marsault ◽  
Kamal Bouarab ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Electron Transport ◽  
Epithelial Cells ◽  
Airway Epithelial Cells ◽  
Plant Secondary Metabolite ◽  
Airway Epithelial ◽  
Small Colony Variants ◽  
Content Type ◽  
Small Colony

ABSTRACTSmall-colony variants (SCVs) often are associated with chronicStaphylococcus aureusinfections, such as those encountered by cystic fibrosis (CF) patients. We report here that tomatidine, the aglycon form of the plant secondary metabolite tomatine, has a potent growth inhibitory activity against SCVs (MIC of 0.12 μg/ml), whereas the growth of normalS. aureusstrains was not significantly altered by tomatidine (MIC, >16 μg/ml). The specific action of tomatidine was bacteriostatic for SCVs and was clearly associated with their dysfunctional electron transport system, as the presence of the electron transport inhibitor 4-hydroxy-2-heptylquinoline-N-oxide (HQNO) caused normalS. aureusstrains to become susceptible to tomatidine. Inversely, the complementation of SCVs' respiratory deficiency conferred resistance to tomatidine. Tomatidine provoked a general reduction of macromolecular biosynthesis but more specifically affected the incorporation of radiolabeled leucine in proteins of HQNO-treatedS. aureusat a concentration corresponding to the MIC against SCVs. Furthermore, tomatidine inhibited the intracellular replication of a clinical SCV in polarized CF-like epithelial cells. Our results suggest that tomatidine eventually will find some use in combination therapy with other traditional antibiotics to eliminate persistent forms ofS. aureus.

scholarly journals Infection of Polarized Airway Epithelial Cells by Normal and Small-Colony Variant Strains of Staphylococcus aureus Is Increased in Cells with Abnormal Cystic Fibrosis Transmembrane Conductance Regulator Function and Is Influenced by NF-κB

2011 ◽  
Vol 79 (9) ◽  
pp. 3541-3551 ◽  
Author(s):  
Gabriel Mitchell ◽  
Gilles Grondin ◽  
Ginette Bilodeau ◽  
André M. Cantin ◽  
François Malouin
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Airway Epithelial Cells ◽  
Transmembrane Conductance Regulator ◽  
Airway Epithelial ◽  
Transmembrane Conductance ◽  
Infection Level ◽  
Content Type ◽  
Small Colony ◽  
Cystic Fibrosis Transmembrane

ABSTRACTThe infection of nonphagocytic host cells byStaphylococcus aureusand more particularly by small-colony variants (SCVs) may contribute to the persistence of this pathogen in the lungs of cystic fibrosis (CF) patients. The development of chronic infections is also thought to be facilitated by the proinflammatory status of CF airways induced by an activation of NF-κB. The aim of this study was to compare the infection of non-CF and CF-like airway epithelial cells byS. aureusstrains (normal and SCVs) and to determine the impact of the interaction between cystic fibrosis transmembrane conductance regulator (CFTR) and NF-κB on the infection level of these cells byS. aureus. We developed anS. aureusinfection model using polarized airway epithelial cells grown at the air-liquid interface and expressing short hairpin RNAs directed against CFTR to mimic the CF condition. A pair of genetically related CF coisolates with the normal and SCV phenotypes was characterized and used. Infection of both cell lines (non-CF and CF-like) was more productive with the SCV strain than with its normal counterpart. However, both normal and SCV strains infected more CF-like than non-CF cells. Accordingly, inhibition of CFTR function by CFTRinh-172 increased theS. aureusinfection level. Experimental activation of NF-κB also increased the level of infection of polarized pulmonary epithelial cells byS. aureus, an event that could be associated with that observed when CFTR function is inhibited or impaired. This study supports the hypothesis that the proinflammatory status of CF tissues facilitates the infection of pulmonary epithelial cells byS. aureus.

scholarly journals Dispersal of Epithelium-Associated Pseudomonas aeruginosa Biofilms

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Anna C. Zemke ◽  
Emily J. D’Amico ◽  
Emily C. Snell ◽  
Angela M. Torres ◽  
Naomi Kasturiarachi ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Epithelial Cells ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Content Type ◽  
Growth Environment ◽  
Human Airway ◽  
Biofilm Dispersal ◽  
Key Features

ABSTRACT Pseudomonas aeruginosa grows in highly antibiotic-tolerant biofilms during chronic airway infections. Dispersal of bacteria from biofilms may restore antibiotic susceptibility or improve host clearance. We describe models to study biofilm dispersal in the nutritionally complex environment of the human airway. P. aeruginosa was cocultured in the apical surface of airway epithelial cells (AECs) in a perfusion chamber. Dispersal, triggered by sodium nitrite, a nitric oxide (NO) donor, was tracked by live cell microscopy. Next, a static model was developed in which biofilms were grown on polarized AECs without flow. We observed that NO-triggered biofilm dispersal was an energy-dependent process. From the existing literature, NO-mediated biofilm dispersal is regulated by DipA, NbdA, RbdA, and MucR. Interestingly, altered signaling pathways appear to be used in this model, as deletion of these genes failed to block NO-induced biofilm dispersal. Similar results were observed using biofilms grown in an abiotic model on glass with iron-supplemented cell culture medium. In cystic fibrosis, airway mucus contributes to the growth environment, and a wide range of bacterial phenotypes are observed; therefore, we tested biofilm dispersal in a panel of late cystic fibrosis clinical isolates cocultured in the mucus overlying primary human AECs. Finally, we examined dispersal in combination with the clinically used antibiotics ciprofloxacin, aztreonam and tobramycin. In summary, we have validated models to study biofilm dispersal in environments that recapitulate key features of the airway and identified combinations of currently used antibiotics that may enhance the therapeutic effect of biofilm dispersal. IMPORTANCE During chronic lung infections, Pseudomonas aeruginosa grows in highly antibiotic-tolerant communities called biofilms that are difficult for the host to clear. We have developed models for studying P. aeruginosa biofilm dispersal in environments that replicate key features of the airway. We found that mechanisms of biofilm dispersal in these models may employ alternative or additional signaling mechanisms, highlighting the importance of the growth environment in dispersal events. We have adapted the models to accommodate apical fluid flow, bacterial clinical isolates, antibiotics, and primary human airway epithelial cells, all of which are relevant to understanding bacterial behaviors in the context of human disease. We also examined dispersal agents in combination with commonly used antipseudomonal antibiotics and saw improved clearance when nitrite was combined with the antibiotic aztreonam.

scholarly journals Staphylococcus aureusBiofilm Growth on Cystic Fibrosis Airway Epithelial Cells Is Enhanced during Respiratory Syncytial Virus Coinfection

mSphere ◽  
2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Megan R. Kiedrowski ◽  
Jordan R. Gaston ◽  
Brian R. Kocak ◽  
Stefanie L. Coburn ◽  
Stella Lee ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Respiratory Syncytial Virus ◽  
Biofilm Formation ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Biofilm Growth ◽  
Content Type ◽  
Syncytial Virus ◽  
Polymicrobial Infections

ABSTRACTStaphylococcus aureusis a major cause of chronic respiratory infection in patients with cystic fibrosis (CF). We recently showed thatPseudomonas aeruginosaexhibits enhanced biofilm formation during respiratory syncytial virus (RSV) coinfection on human CF airway epithelial cells (AECs). The impact of respiratory viruses on other bacterial pathogens during polymicrobial infections in CF remains largely unknown. To investigate ifS. aureusbiofilm growth in the CF airways is impacted by virus coinfection, we evaluatedS. aureusgrowth on CF AECs. Initial studies showed an increase inS. aureusgrowth over 24 h, and microscopy revealed biofilm-like clusters of bacteria on CF AECs. Biofilm growth was enhanced when CF AECs were coinfected with RSV, and this observation was confirmed withS. aureusCF clinical isolates. Apical conditioned medium from RSV-infected cells promotedS. aureusbiofilms in the absence of the host epithelium, suggesting that a secreted factor produced during virus infection benefitsS. aureusbiofilms. Exogenous iron addition did not significantly alter biofilm formation, suggesting that it is not likely the secreted factor. We further characterizedS. aureus-RSV coinfection in our model using dual host-pathogen RNA sequencing, allowing us to observe specific contributions ofS. aureusand RSV to the host response during coinfection. Using the dual host-pathogen RNA sequencing approach, we observed increased availability of nutrients from the host and upregulation ofS. aureusgenes involved in growth, protein translation and export, and amino acid metabolism during RSV coinfection.IMPORTANCEThe airways of individuals with cystic fibrosis (CF) are commonly chronically infected, andStaphylococcus aureusis the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity ofS. aureuslung infections in CF. We investigated the relationship betweenS. aureusand the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhancesS. aureusbiofilm growth. However, iron, which was previously found to be a significant factor influencingPseudomonas aeruginosabiofilms during virus coinfection, plays a minor role inS. aureuscoinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections.

Differential expression of ORCC and CFTR induced by low temperature in CF airway epithelial cells

1995 ◽  
Vol 268 (1) ◽  
pp. C243-C251 ◽  
Author(s):  
M. E. Egan ◽  
E. M. Schwiebert ◽  
W. B. Guggino
Keyword(s):  
Cystic Fibrosis ◽  
Epithelial Cells ◽  
Incubation Temperature ◽  
Cell Types ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Channel Activity ◽  
Patch Clamp Recording ◽  
Cl Channel ◽  
Channel Expression

When nonepithelial cell types expressing the delta F508-cystic fibrosis transmembrane conductance regulator (CFTR) mutation are grown at reduced temperatures, the mutant protein can be properly processed. The effect of low temperatures on Cl- channel activity in airway epithelial cells that endogenously express the delta F508-CFTR mutation has not been investigated. Therefore, we examined the effect of incubation temperature on both CFTR and outwardly rectifying Cl- channel (ORCC) activity in normal, in cystic fibrosis (CF)-affected, and in wild-type CFTR-complemented CF airway epithelia with use of a combination of inside-out and whole cell patch-clamp recording, 36Cl- efflux assays, and immunocytochemistry. We report that incubation of CF-affected airway epithelial cells at 25-27 degrees C is associated with the appearance of a protein kinase A-stimulated CFTR-like Cl- conductance. In addition to the appearance of CFTR Cl- channel activity, there is, however, a decrease in the number of active ORCC when cells are grown at 25-27 degrees C, suggesting that the decrease in incubation temperature may be associated with multiple alterations in ion channel expression and/or regulation in airway epithelial cells.

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