[Na+ Transport in the lungs: differential impact of ENaC in the airways and alveoli].
Na+ transport by airway epithelial cells, in conjunction with Cl- secretion is crucial for maintaining an adequate level of airway surface liquid (ASL) for an effective mucociliary clearance by the ciliated airway epithelial cells. It is also an important mechanism for lung liquid absorption at birth and oedema absorption during an acute respiratory distress syndrome (ARDS). The epithelial Na+ channel (ENaC) is the channel mostly involved in this process. The consequences of an imbalance in ENaC activity in the airways and in the distal lung are different. Experimental over expression of ENaC in the airways leads to a decrease in mucociliary clearance and inflammation similar to cystic fibrosis and chronic bronchitis. However, bacterial and viral pathogens, as well as pro-inflammatory cytokines present during lung infection downregulate ENaC expression and activity in airway and alveolar epithelial cells. ENaC downregulation by pathogens or inflammatory products could participate in the modulation of the severity of ARDS. Pharmacological strategies that modulate ENaC expression or activity could be important in the treatment of different lung diseases since it is actively involved in the lung innate defence mechanisms.
Dagenais
André
A
Centre de recherche, Centre hospitalier de l'Université de Montréal-CHUM-Hôtel-Dieu, et département de médecine, Université de Montréal, 3850, rue Saint-Urbain, Montréal, Québec, H2W 1T7 Canada. andre.dagenais.chum@ssss.gouv.qc.ca
Boncoeur
Emilie
E
Berthiaume
Yves
Y
D053503:Epithelial Sodium Channels / Q000378:metabolism / Q000627:therapeutic use; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D008168:Lung / Q000033:anatomy & histology / Q000378:metabolism*; D008171:Lung Diseases / Q000188:drug therapy / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D053503:Epithelial Sodium Channels; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase