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Studies on the functional expression of epithelial sodium channel delta subunit (δ‐ENaC) in human respiratory epithelial cells in vitro
Author(s) -
Schwagerus Elena,
Illek Beate,
Fischer Horst,
Ehrhardt Carsten
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.696.1
Subject(s) - epithelial sodium channel , capsazepine , microbiology and biotechnology , a549 cell , western blot , ussing chamber , chemistry , ion channel , cell culture , cell , biology , in vitro , sodium , biochemistry , receptor , transient receptor potential channel , gene , genetics , organic chemistry , trpv1
While epithelial sodium channel α‐, β‐ and γ‐subunits are crucial for the ion and fluid balance in the lung, the role of the δ‐subunit remains unclear. Here, we studied δ‐ENaC expression and its contribution to ion transport function in human respiratory epithelial cells. Expression of the δ‐ENaC was investigated in human respiratory epithelial cell lines (A549, H441 and Calu‐3) as well as in alveolar epithelial cells in primary culture (hAEpC) on both gene and protein levels. In Ussing chamber studies, the effects of reported δ‐ENaC modulators (i.e., Evans blue, capsazepine and icilin) were studied in H441 and Calu‐3 cell monolayers. All investigated cell types showed presence of both δ‐ENaC mRNA and protein, as revealed by PCR, Western blot and immunofluorescence microscopy. All pharmacological modulators resulted in blockade of Na + current in H441 cell monolayers. Interestingly, in Calu‐3 cell monolayers only capsazepine showed an inhibitory effect, whereas Evans blue and icilin increased ISC, which were mostly Cl − dependent currents. These data suggest a physiological role for δ‐ENaC in human respiratory epithelium. However, further studies need to determine δ‐ENaC regulation and the specificity of the observed pharmacological effects. ES is funded by an IRCSET postgraduate scholarship.