Control of ion transport in mammalian airways by protease activated receptors type 2 (PAR-2).
FASEB J
; 19(8): 969-70, 2005 Jun.
Article
em En
| MEDLINE
| ID: mdl-15809358
ABSTRACT
Protease-activated receptors (PARs) are widely distributed in human airways. They couple to G- proteins and are activated after proteolytic cleavage of the N terminus of the receptor. Evidence is growing that PAR subtype 2 plays a pivotal role in inflammatory airway diseases, such as allergic asthma or bronchitis. However, nothing is known about the effects of PAR-2 on electrolyte transport in the native airways. PAR-2 is expressed in airway epithelial cells, where they are activated by mast cell tryptase, neutrophil proteinase 3, or trypsin. Recent studies produced conflicting results about the functional consequence of PAR-2 stimulation. Here we report that stimulation of PAR-2 receptors in mouse and human airways leads to a change in electrolyte transport and a shift from absorption to secretion. Although PAR-2 appears to be expressed on both sides of the epithelium, only basolateral stimulation results in inhibition of amiloride sensitive Na+ conductance and stimulation of both luminal Cl- channels and basolateral K+ channels. The present data indicate that these changes occur through activation of phospholipase C and increase in intracellular Ca2+, which activates basolateral SK4 K+ channels and luminal Ca2+-dependent Cl- channels. In addition, the present data suggest a PAR-2 mediated release of prostaglandin E2, which may contribute to the secretory response. In conclusion, these results provide further evidence for a role of PAR-2 in inflammatory airway disease stimulation of these receptors may cause accumulation of airway surface liquid, which, however, may help to flush noxious stimuli away from the affected airways.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sistema Respiratório
/
Transporte de Íons
/
Receptor PAR-2
Idioma:
En
Revista:
FASEB J
Assunto da revista:
BIOLOGIA
/
FISIOLOGIA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Alemanha