An electrogenic amino acid transporter in the apical membrane of cultured human bronchial epithelial cells

Luis J V Galietta, Luciana Musante, Leila Romio, Ubaldo Caruso, Annarita Fantasia, Andrea Gazzolo, Luca Romano, Oliviero Sacco, Giovanni A. Rossi, Luigi Varesio, Olga Zegarra-Moran

Research output: Contribution to journalArticlepeer-review

Abstract

We performed using chamber experiments on cultured human bronchial epithelial cells to look for the presence of electrogenic dibasic amino acid transport. Apical but not basolateral L-arginine (10-1,000 μM) increased the short-circuit current. Maximal effect and EC50 were ~3.5 μA/cm2 and 80 μM, respectively, in cells from normal subjects and cystic fibrosis patients. The involvement of nitric oxide was ruled out because a nitric oxide synthase inhibitor (N(G)-nitro-L-arginine methyl ester) did not decrease the arginine-dependent current. Apical L-lysine, L-alanine, and L- proline, but not aspartic acid, were also effective in increasing the short- circuit current, with EC50 values ranging from 26 to 971 μM. Experiments performed with radiolabeled arginine demonstrated the presence of an Na+- dependent concentrative transporter on the apical membrane of bronchial cells. This transporter could be important in vivo to maintain a low amino acid concentration in the fluid covering the airway surface.

Original languageEnglish
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume275
Issue number5 19-5
Publication statusPublished - 1998

Keywords

  • Airway epithelium
  • Arginine transport
  • Cystic fibrosis
  • Nitric oxide
  • Pulmonary surfactant

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Cell Biology
  • Physiology
  • Physiology (medical)

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