Modulation of epithelial sodium channel (ENaC) expression in mouse lung infected with <it>Pseudomonas aeruginosa</it>

• Main Authors: Radzioch Danuta, Guilbault Claudine, Gosselin Diane, Dagenais André, Berthiaume Yves
• Format: Article
• Language: English
• Published: BMC 2005-01-01
• Series: Respiratory Research
• Online Access: http://respiratory-research.com/content/6/1/2

<p>Abstract</p> <p>Background</p> <p>The intratracheal instillation of <it>Pseudomonas aeruginosa </it>entrapped in agar beads in the mouse lung leads to chronic lung infection in susceptible mouse strains. As the infection generates a strong inflammatory response with some lung edema, we tested if it could modulate the expression of genes involved in lung liquid clearance, such as the α, β and γ subunits of the epithelial sodium channel (ENaC) and the catalytic subunit of Na⁺-K⁺-ATPase.</p> <p>Methods</p> <p><it>Pseudomonas aeruginosa </it>entrapped in agar beads were instilled in the lung of resistant (BalB/c) and susceptible (DBA/2, C57BL/6 and A/J) mouse strains. The mRNA expression of ENaC and Na⁺-K⁺-ATPase subunits was tested in the lung by Northern blot following a 3 hours to 14 days infection.</p> <p>Results</p> <p>The infection of the different mouse strains evoked regulation of α and β ENaC mRNA. Following Pseudomonas instillation, the expression of αENaC mRNA decreased to a median of 43% on days 3 and 7 after infection and was still decreased to a median of 45% 14 days after infection (p < 0.05). The relative expression of βENaC mRNA was transiently increased to a median of 241%, 24 h post-infection before decreasing to a median of 43% and 54% of control on days 3 and 7 post-infection (p < 0.05). No significant modulation of γENaC mRNA was detected although the general pattern of expression of the subunit was similar to α and β subunits. No modulation of α₁Na⁺-K⁺-ATPase mRNA, the catalytic subunit of the sodium pump, was recorded. The distinctive expression profiles of the three subunits were not different, between the susceptible and resistant mouse strains.</p> <p>Conclusions</p> <p>These results show that <it>Pseudomonas </it>infection, by modulating ENaC subunit expression, could influence edema formation and clearance in infected lungs.</p>