Duodenal cytochrome b: a novel ferrireductase in airway epithelial cells.

Journal Article (Journal Article)

Catalytically active iron in the lung causes oxidative stress and promotes microbial growth that can be limited by intracellular sequestration of iron within ferritin. Because cellular iron uptake requires membrane ferrireductase activity that in the gut can be provided by duodenal cytochrome b (Dcytb), we sought Dcytb in the lung to test the hypothesis that it contributes to epithelial iron regulation by reducing Fe(3+) for cellular iron transport. Dcytb expression was found in respiratory epithelium in vitro and in vivo and was responsive to iron concentration. Iron transport was measured in human bronchial epithelial (HBE) cells using inductively coupled plasma atomic emission spectroscopy and was demonstrated to be partially inhibited in the presence of Dcytb-blocking antibody, suggesting that Dcytb reduces Fe(3+) for cellular iron transport. A definite source of reducing equivalents for Dcytb was sought but not identified. We found no evidence that ascorbate was involved but did demonstrate that O(2)(-). production decreased when Dcytb function was blocked. The presence of Dcytb in airway epithelial cells and its regulation by iron therefore may contribute to pulmonary cytoprotection.

Full Text

Duke Authors

Cited Authors

  • Turi, JL; Wang, X; McKie, AT; Nozik-Grayck, E; Mamo, LB; Crissman, K; Piantadosi, CA; Ghio, AJ

Published Date

  • August 2006

Published In

Volume / Issue

  • 291 / 2

Start / End Page

  • L272 - L280

PubMed ID

  • 16510471

International Standard Serial Number (ISSN)

  • 1040-0605

Digital Object Identifier (DOI)

  • 10.1152/ajplung.00342.2005


  • eng

Conference Location

  • United States