Lung disease phenotypes caused by overexpression of combinations of α-, ß-, and γ-subunits of the epithelial sodium channel in mouse airways.
Am J Physiol Lung Cell Mol Physiol
; 314(2): L318-L331, 2018 02 01.
Article
in En
| MEDLINE
| ID: mdl-29074490
ABSTRACT
The epithelial Na+ channel (ENaC) regulates airway surface hydration. In mouse airways, ENaC is composed of three subunits, α, ß, and γ, which are differentially expressed (α > ß > γ). Airway-targeted overexpression of the ß subunit results in Na+ hyperabsorption, causing airway surface dehydration, hyperconcentrated mucus with delayed clearance, lung inflammation, and perinatal mortality. Notably, mice overexpressing the α- or γ-subunit do not exhibit airway Na+ hyperabsorption or lung pathology. To test whether overexpression of multiple ENaC subunits produced Na+ transport and disease severity exceeding that of ßENaC-Tg mice, we generated double (αß, αγ, ßγ) and triple (αßγ) transgenic mice and characterized their lung phenotypes. Double αγENaC-Tg mice were indistinguishable from WT littermates. In contrast, double ßγENaC-Tg mice exhibited airway Na+ absorption greater than that of ßENaC-Tg mice, which was paralleled by worse survival, decreased mucociliary clearance, and more severe lung pathology. Double αßENaC-Tg mice exhibited Na+ transport rates comparable to those of ßENaC-Tg littermates. However, αßENaC-Tg mice had poorer survival and developed severe parenchymal consolidation. In situ hybridization (RNAscope) analysis revealed both alveolar and airway αENaC-Tg overexpression. Triple αßγENaC-Tg mice were born in Mendelian proportions but died within the first day of life, and the small sample size prevented analyses of cause(s) of death. Cumulatively, these results indicate that overexpression of ßENaC is rate limiting for generation of pathological airway surface dehydration. Notably, airway co-overexpression of ß- and γENaC had additive effects on Na+ transport and disease severity, suggesting dose dependency of these two variables.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pneumonia
/
Respiratory Mucosa
/
Epithelial Sodium Channels
/
Lung Diseases
Type of study:
Etiology_studies
Limits:
Animals
Language:
En
Journal:
Am J Physiol Lung Cell Mol Physiol
Journal subject:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Year:
2018
Type:
Article