Apical location of ferroportin 1 in airway epithelia and its role in iron detoxification in the lung

Funmei Yang, David J. Haile, Xinchao Wang, Lisa A. Dailey, Jacqueline G. Stonehuerner, Andrew J. Ghio

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

Ferroportin 1 (FPN1; aka MTP1, IREG1, and SLC40A1), which was originally identified as a basolateral iron transporter crucial for nutritional iron absorption in the intestine, is expressed in airway epithelia and upregulated when these cells are exposed to iron. Using immunofluorescence labeling and confocal microscopic imaging techniques, we demonstrate that in human and rodent lungs, FPN1 localizes subcellularly to the apical but not basolateral membrane of the airway epithelial cells. The role of airway epithelial cells in iron mobilization in the lung was studied in an in vitro model of the polarized airway epithelium. Normal human bronchial epithelial cells, grown on membrane supports until differentiated, were exposed to iron, and the efficiency and direction of iron transportation were studied. We found that these cells can efficiently take up iron across the apical but not basolateral surface in a concentration-dependent manner. Most of the iron taken up by the cells is then released into the medium within 8 h in the form of less reactive protein-bound complexes including ferritin and transferrin. Interestingly, iron release also occurred across the apical but not basolateral membrane. Our findings indicate that FPN1, depending on its subcellular location, could have distinct functions in iron homeostasis in different cells and tissues. Although it is responsible for exporting nutrient iron from enterocytes to the circulation in the intestine, it could play a role in iron detoxification in airway epithelial cells in the lung.

Original languageEnglish (US)
Pages (from-to)L14-L23
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume289
Issue number1 33-1
DOIs
StatePublished - Jul 2005

Keywords

  • Divalent metal transporter-1
  • Ferritin
  • Iron metabolism
  • Transferrin

ASJC Scopus subject areas

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

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