scholarly journals Nedd4–2 does not regulate wt-CFTR in human airway epithelial cells

2012 ◽  
Vol 303 (8) ◽  
pp. L720-L727 ◽  
Author(s):  
Katja Koeppen ◽  
Chris Chapline ◽  
J. Denry Sato ◽  
Bruce A. Stanton

The cystic fibrosis transmembrane conductance regulator (CFTR), a Cl− channel in airway epithelial cells, plays an important role in maintaining the volume of the airway surface liquid and therefore mucociliary clearance of respiratory pathogens. A recent study has shown that the E3 ubiquitin ligase Neural precursor cells expressed developmentally downregulated (Nedd4–2) ubiquitinates ΔF508-CFTR in pancreatic epithelial cells and that siRNA-mediated silencing of Nedd4–2 increases plasma membrane ΔF508-CFTR. Because the role of Nedd4–2 in regulating wild-type (wt)-CFTR in airway epithelial cells is unknown, studies were conducted to test the hypothesis that Nedd4–2 also ubiquitinates wt-CFTR and regulates its plasma membrane abundance. We found that Nedd4–2 did not affect wt-CFTR Cl− currents in Xenopus oocytes. Likewise, overexpression of Nedd4–2 in human airway epithelial cells did not alter the amount of ubiquitinated wt-CFTR. siRNA knockdown of Nedd4–2 in human airway epithelial cells had no effect on ubiquitination or apical plasma membrane abundance of wt-CFTR. Thus Nedd4–2 does not ubiquitinate and thereby regulate wt-CFTR in human airway epithelial cells.

2006 ◽  
Vol 290 (3) ◽  
pp. C862-C872 ◽  
Author(s):  
Agnieszka Swiatecka-Urban ◽  
Sophie Moreau-Marquis ◽  
Daniel P. MacEachran ◽  
John P. Connolly ◽  
Caitlin R. Stanton ◽  
...  

The most common mutation in the CFTR gene in individuals with cystic fibrosis (CF), ΔF508, leads to the absence of CFTR Cl−channels in the apical plasma membrane, which in turn results in impairment of mucociliary clearance, the first line of defense against inhaled bacteria. Pseudomonas aeruginosa is particularly successful at colonizing and chronically infecting the lungs and is responsible for the majority of morbidity and mortality in patients with CF. Rescue of ΔF508-CFTR by reduced temperature or chemical means reveals that the protein is at least partially functional as a Cl−channel. Thus current research efforts have focused on identification of drugs that restore the presence of CFTR in the apical membrane to alleviate the symptoms of CF. Because little is known about the effects of P. aeruginosa on CFTR in the apical membrane, whether P. aeruginosa will affect the efficacy of new drugs designed to restore the plasma membrane expression of CFTR is unknown. Accordingly, the objective of the present study was to determine whether P. aeruginosa affects CFTR-mediated Cl−secretion in polarized human airway epithelial cells. We report herein that a cell-free filtrate of P. aeruginosa reduced CFTR-mediated transepithelial Cl−secretion by inhibiting the endocytic recycling of CFTR and thus the number of WT-CFTR and ΔF508-CFTR Cl−channels in the apical membrane in polarized human airway epithelial cells. These data suggest that chronic infection with P. aeruginosa may interfere with therapeutic strategies aimed at increasing the apical membrane expression of ΔF508-CFTR.


2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Jennifer Bomberger ◽  
Denry Sato ◽  
Bonita Coutermarsh ◽  
Roxanna Barnaby ◽  
M Christin Chapline ◽  
...  

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Jennifer Bomberger ◽  
J. Denry Sato ◽  
Christine Chapline ◽  
Bonita Coutermarsh ◽  
Roxanna Barnaby ◽  
...  

PLoS ONE ◽  
2014 ◽  
Vol 9 (2) ◽  
pp. e89599 ◽  
Author(s):  
Jennifer M. Bomberger ◽  
Bonita A. Coutermarsh ◽  
Roxanna L. Barnaby ◽  
J. Denry Sato ◽  
M. Christine Chapline ◽  
...  

2012 ◽  
Vol 303 (6) ◽  
pp. L509-L518 ◽  
Author(s):  
Thomas H. Hampton ◽  
Alicia E. Ballok ◽  
Jennifer M. Bomberger ◽  
Melanie R. Rutkowski ◽  
Roxanna Barnaby ◽  
...  

In the clinical setting, mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene enhance the inflammatory response in the lung to Pseudomonas aeruginosa ( P. aeruginosa ) infection. However, studies on human airway epithelial cells in vitro have produced conflicting results regarding the effect of mutations in CFTR on the inflammatory response to P. aeruginosa, and there are no comprehensive studies evaluating the effect of P. aeruginosa on the inflammatory response in airway epithelial cells with the ΔF508/ΔF508 genotype and their matched CF cell line rescued with wild-type (wt)-CFTR. CFBE41o- cells (ΔF508/ΔF508) and CFBE41o- cells complemented with wt-CFTR (CFBE-wt-CFTR) have been used extensively as an experimental model to study CF. Thus the goal of this study was to examine the effect of P. aeruginosa on gene expression and cytokine/chemokine production in this pair of cells. P. aeruginosa elicited a more robust increase in cytokine and chemokine expression (e.g., IL-8, CXCL1, CXCL2 and TNF-α) in CFBE-wt-CFTR cells compared with CFBE-ΔF508-CFTR cells. These results demonstrate that CFBE41o- cells complemented with wt-CFTR mount a more robust inflammatory response to P. aeruginosa than CFBE41o-ΔF508/ΔF508-CFTR cells. Taken together with other published studies, our data demonstrate that there is no compelling evidence to support the view that mutations in CFTR induce a hyperinflammatory response in human airway epithelial cells in vivo . Although the lungs of patients with CF have abundant levels of proinflammatory cytokines and chemokines, because the lung is populated by immune cells and epithelial cells there is no way to know, a priori, whether airway epithelial cells in the CF lung in vivo are hyperinflammatory in response to P. aeruginosa compared with non-CF lung epithelial cells. Thus studies on human airway epithelial cell lines and primary cells in vitro that propose to examine the effect of mutations in CFTR on the inflammatory response to P. aeruginosa have uncertain clinical significance with regard to CF.


2008 ◽  
Vol 295 (1) ◽  
pp. L25-L37 ◽  
Author(s):  
Sophie Moreau-Marquis ◽  
Jennifer M. Bomberger ◽  
Gregory G. Anderson ◽  
Agnieszka Swiatecka-Urban ◽  
Siying Ye ◽  
...  

Enhanced antibiotic resistance of Pseudomonas aeruginosa in the cystic fibrosis (CF) lung is thought to be due to the formation of biofilms. However, there is no information on the antibiotic resistance of P. aeruginosa biofilms grown on human airway epithelial cells or on the effects of airway cells on biofilm formation by P. aeruginosa. Thus we developed a coculture model and report that airway cells increase the resistance of P. aeruginosa to tobramycin (Tb) by >25-fold compared with P. aeruginosa grown on abiotic surfaces. Therefore, the concentration of Tb required to kill P. aeruginosa biofilms on airway cells is 10-fold higher than the concentration achievable in the lungs of CF patients. In addition, CF airway cells expressing ΔF508-CFTR significantly enhanced P. aeruginosa biofilm formation, and ΔF508 rescue with wild-type CFTR reduced biofilm formation. Iron (Fe) content of the airway in CF is elevated, and Fe is known to enhance P. aeruginosa growth. Thus we investigated whether enhanced biofilm formation on ΔF508-CFTR cells was due to increased Fe release by airway cells. We found that airway cells expressing ΔF508-CFTR released more Fe than cells rescued with WT-CFTR. Moreover, Fe chelation reduced biofilm formation on airway cells, whereas Fe supplementation enhanced biofilm formation on airway cells expressing WT-CFTR. These data demonstrate that human airway epithelial cells promote the formation of P. aeruginosa biofilms with a dramatically increased antibiotic resistance. The ΔF508-CFTR mutation enhances biofilm formation, in part, by increasing Fe release into the apical medium.


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