scholarly journals Novel Effects of Azithromycin on Tight Junction Proteins in Human Airway Epithelia

2006 ◽  
Vol 50 (5) ◽  
pp. 1805-1812 ◽  
Author(s):  
Valthor Asgrimsson ◽  
Thorarinn Gudjonsson ◽  
Gudmundur Hrafn Gudmundsson ◽  
Olafur Baldursson
Keyword(s):  
Cystic Fibrosis ◽  
Tight Junction ◽  
Electrical Resistance ◽  
Transepithelial Electrical Resistance ◽  
Tight Junction Proteins ◽  
Airway Epithelia ◽  
Diffuse Panbronchiolitis ◽  
Human Airway ◽  
Junction Proteins ◽  
Human Airway Epithelia

ABSTRACT The macrolide antibiotic azithromycin improves lung function and prognosis among patients with cystic fibrosis or diffuse panbronchiolitis, independently of bacterial eradication. Anti-inflammatory effects have been implicated, but data from in vivo studies are scarce, and the link between abnormal electrolyte content in airway surface liquid and bronchial infections remains uncertain. In the present study, we treated human airway epithelia on filter supports with azithromycin and monitored transepithelial electrical resistance. We found that azithromycin increased transepithelial electrical resistance of airway epithelia in a dose-dependent manner. Immunocytochemistry and Western blotting showed that addition of azithromycin changed the locations of proteins in cell cultures and induced processing of the tight junction proteins claudin-1 and claudin-4, occludin, and junctional adhesion molecule-A. These effects were reversible, and no effect was seen when cells were treated with penicillin or erythromycin. The data indicate that azithromycin increases the transepithelial electrical resistance of human airway epithelia by changing the processing of tight junction proteins. The results are novel and may help explain the beneficial effects of azithromycin in patients with cystic fibrosis, diffuse panbronchiolitis, and community-acquired pneumonia.

scholarly journals 115 Azithromycin affects the processing of tight junction proteins and ENaC in human airway epithelia in vitro

2006 ◽  
Vol 5 ◽  
pp. S26
Author(s):  
V. Asgrimsson ◽  
T. Gudjonsson ◽  
G.H. Gudmundsson ◽  
S. Halldorsson ◽  
O. Baldursson
Keyword(s):  
Tight Junction ◽  
Tight Junction Proteins ◽  
Airway Epithelia ◽  
Human Airway ◽  
Junction Proteins ◽  
Human Airway Epithelia

Basolateral chloride current in human airway epithelia

2007 ◽  
Vol 293 (4) ◽  
pp. L991-L999 ◽  
Author(s):  
Omar A. Itani ◽  
Fred S. Lamb ◽  
James E. Melvin ◽  
Michael J. Welsh
Keyword(s):  
Cystic Fibrosis ◽  
Signaling Pathways ◽  
Basolateral Membrane ◽  
Primary Cultures ◽  
Cell Swelling ◽  
Disulfonic Acid ◽  
Airway Epithelia ◽  
Human Airway ◽  
Well Differentiated ◽  
Human Airway Epithelia

Electrolyte transport by airway epithelia regulates the quantity and composition of liquid covering the airways. Previous data indicate that airway epithelia can absorb NaCl. At the apical membrane, cystic fibrosis transmembrane conductance regulator (CFTR) provides a pathway for Cl− absorption. However, the pathways for basolateral Cl− exit are not well understood. Earlier studies, predominantly in cell lines, have reported that the basolateral membrane contains a Cl− conductance. However, the properties have varied substantially in different epithelia. To better understand the basolateral Cl− conductance in airway epithelia, we studied primary cultures of well-differentiated human airway epithelia. The basolateral membrane contained a Cl− current that was inhibited by 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS). The current-voltage relationship was nearly linear, and the halide selectivity was Cl− > Br− >> I−. Several signaling pathways increased the current, including elevation of cellular levels of cAMP, activation of protein kinase C (PKC), and reduction of pH. In contrast, increasing cell Ca2+ and inducing cell swelling had no effect. The basolateral Cl− current was present in both cystic fibrosis (CF) and non-CF airway epithelia. Likewise, airway epithelia from wild-type mice and mice with disrupted genes for ClC-2 or ClC-3 all showed similar Cl− currents. These data suggest that the basolateral membrane of airway epithelia possesses a Cl− conductance that is not due to CFTR, ClC-2, or ClC-3. Its regulation by cAMP and PKC signaling pathways suggests that coordinated regulation of Cl− conductance in both apical and basolateral membranes may be important in controlling transepithelial Cl− movement.

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