New light for old enigmas in epithelial transport?

The maintenance of a layer of fluid at the surface of the air-ways and the gas exchange region of the lung is an essential activity of the respiratory epithelium, ensuring efficient gas exchange and mucociliary clearance-driven bacterial removal, among other functions. Regulation of the height of this airway or alveolar surface liquid layer is dependent on opposing secretory and absorptive fluid transportprocessesthat,inturn,aredrivenbyiontransport.Secretion into the alveolar surface liquid layer requires blood-to-lumen Cl − flow mediated by cystic fibrosis transmembrane conductance regulator (CFTR) channels, whose functional significance is highlighted by the fact that their impairment is associated to cystic fibrosis. Absorptive fluxes affecting the alveolar surface liquid layer are dependent on Na + movement mediated by the apical membrane epithelial Na + channel (ENaC) and basolaterally located Na + –K + pump. The relevance of the ENaC in the respiratory system can be gauged from the consequence of human mutations enhancing its activity or overexpression in trans-genic mice, both of which lead to cystic fibrosis-like pathology. The ENaC and its relationship with Na + –K + pump are therefore important in the physiology of the respiratory epithelium and in potentially life-threatening pathological states. Our knowledge of ENaC physiology and the cell biology determining its expression and localization are of great interest. Two remarkable observations are presented in a paper from Luis Galietta ' s laboratory in this issue of Experimental Physiology (Musante et al., 2019). First, immunolocalization

• Publication year

  2019

• Venue

  Experimental Physiology

• Publication date

  2019-04-08

• Fields of study

  Biology, Medicine, Chemistry, Environmental Science

• Identifiers
  DOI 10.1113/EP087739PMID 30924215
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

• Peripheral localization of the epithelial sodium channel in the apical membrane of bronchial epithelial cells

  2019influential reference
• Directional Fluid Transport across Organ-Blood Barriers: Physiology and Cell Biology.

  2017cited by this paper
• Fluid transport across leaky epithelia: central role of the tight junction and supporting role of aquaporins.

  2010influential reference
• Sodium-coupled sugar transport: effects on intracellular sodium activities and sodium-pump activity.

  1984cited by this paper
• Standing-Gradient Osmotic Flow

  1967cited by this paper

• No citing papers are available for this paper.