Receptor for advanced glycation end-products regulates lung fluid balance via protein kinase C-gp91phox signaling to epithelial sodium channels

Charles A. Downs, Lisa H. Kreiner, Nicholle M. Johnson, Lou Ann Brown, My N. Helms

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


The receptor for advanced glycation end-products (RAGE), a multiligand member of the Ig family, may play a crucial role in the regulation of lung fluid balance. We quantified soluble RAGE (sRAGE), a decoy isoform, and advanced glycation end-products (AGEs) from the bronchoalveolar lavage fluid of smokers and nonsmokers, and tested the hypothesis that AGEs regulate lung fluid balance through protein kinase C (PKC)-gp91phox signaling to the epithelial sodium channel (ENaC). Human bronchoalveolar lavage samples fromsmokers showed increasedAGEs (9.02 ± 3.03 μg versus 2.48 ± 0.53 μg), lower sRAGE (1,205 ± 292 pg/ml versus 1,9106263 pg/ml), and lower volume(s) of epithelial lining fluid (97 ± 14 ml versus 133 ± 17 ml). sRAGE levels did not predict ELF volumes in nonsmokers; however, in smokers, higher volumes of ELF were predicted with higher levels of sRAGE. Single-channel patch clamp analysis of rat alveolar epithelial type 1 cells showed that AGEs increased ENaC activity measured as the product of the number of channels (N) and the open probability (Po) (NPo) from 0.19 ± 0.08 to 0.83 ± 0.22 (P = 0.017) and the subsequent addition of 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-N-oxyl decreased ENaC NPo to 0.15 ± 0.07 (P = 0.01). In type 2 cells, human AGEs increased ENaC NPo from 0.12 ± 0.05 to 0.53 ± 0.16 (P = 0.025) and the addition of 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-N -oxyl decreased ENaC NPo to 0.10 ± 0.03 ( P = 0.013). Using molecular and biochemical techniques, we observed that inhibition of RAGE and PKC activity attenuated AGE-induced activation of ENaC. AGEs induced phosphorylation of p47phox and increased gp91phox dependent reactive oxygen species production, a response that was abrogated with RAGE or PKC inhibition. Finally, tracheal instillation of AGEs promoted clearance of lung fluid, whereas concomitant inhibition of RAGE, PKC, and gp91phox abrogated the response.

Original languageEnglish (US)
Pages (from-to)75-87
Number of pages13
JournalAmerican journal of respiratory cell and molecular biology
Issue number1
StatePublished - Jan 1 2015
Externally publishedYes


  • Acute respiratory distress syndrome
  • Alveolar microenvironment
  • Chronic obstructive pulmonary disease
  • Lung injury
  • Pulmonary edema

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology


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