Augmented internalisation of ferroportin to late endosomes impairs iron uptake by enterocyte-like IEC-6 cells

Phillip Oates, Carla Thomas

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Absorption of iron occurs by duodenal enterocytes, involving uptake by the divalent metal transporter-1 (DMT1) and release by ferroportin. Ferroportin responds to the hepatocyte-produced 25-amino-acid-peptide hepcidin-25 by undergoing internalisation to late endosomes that impair iron release. Ferroportin is also expressed on the apical membrane of polarised Caco-2 cells, rat intestinal cells and in IEC-6 cells (an intestinal epithelial cell line). A blocking antibody to ferroportin also impairs the uptake, but not the release, of iron. In this study IEC-6 cells were used to study the mechanism of impairment or recovery from impairment produced by the blocking antibody and the fate of DMT1 and ferroportin. Uptake of 1 mu M Fe(II) was studied by adding the antibody from time 0 and after adding or removing the antibody once a steady state had been reached. Surface binding, maximum iron transport rate V-max and transporter affinity (K-m) were measured after impairment of iron uptake. Ferroportin and DMT1 distribution were assessed by immunofluorescence microscopy. Antibody-mediated impairment, or recovery from impairment, of Fe(II) uptake occurred within minutes. Impairment was lost when the antibody was combined with the immunizing peptide. DMT1 and ferroportin undergo internalisation to late endosomes and, in the presence of the antibody, augmented internalisation of DMT1 and ferroportin caused swelling of late endosomes. Surface binding of Fe(II) and iron transport V-max were reduced by 50%, indicating that the antibody removed membrane-bound DMT1. The ferroportin antibody induced rapid turnover of membrane ferroportin and DMT1 and its internalisation to late endosomes, resulting in impaired Fe(II) uptake.
Original languageEnglish
Pages (from-to)317-325
JournalPfluegers Archiv: European journal of physiology
Volume450
Issue number5
DOIs
Publication statusPublished - 2005

Fingerprint

Enterocytes
Endosomes
Iron
Antibodies
Blocking Antibodies
Membranes
metal transporting protein 1
Hepcidins
Recovery
Peptides
Caco-2 Cells
solute carrier family 11- (proton-coupled divalent metal ion transporters), member 2
Fluorescence Microscopy
Swelling
Rats
Hepatocytes
Microscopic examination
Epithelial Cells
Amino Acids
Cell Line

Cite this

@article{c2844f772abf4158a5e88788407e5880,
title = "Augmented internalisation of ferroportin to late endosomes impairs iron uptake by enterocyte-like IEC-6 cells",
abstract = "Absorption of iron occurs by duodenal enterocytes, involving uptake by the divalent metal transporter-1 (DMT1) and release by ferroportin. Ferroportin responds to the hepatocyte-produced 25-amino-acid-peptide hepcidin-25 by undergoing internalisation to late endosomes that impair iron release. Ferroportin is also expressed on the apical membrane of polarised Caco-2 cells, rat intestinal cells and in IEC-6 cells (an intestinal epithelial cell line). A blocking antibody to ferroportin also impairs the uptake, but not the release, of iron. In this study IEC-6 cells were used to study the mechanism of impairment or recovery from impairment produced by the blocking antibody and the fate of DMT1 and ferroportin. Uptake of 1 mu M Fe(II) was studied by adding the antibody from time 0 and after adding or removing the antibody once a steady state had been reached. Surface binding, maximum iron transport rate V-max and transporter affinity (K-m) were measured after impairment of iron uptake. Ferroportin and DMT1 distribution were assessed by immunofluorescence microscopy. Antibody-mediated impairment, or recovery from impairment, of Fe(II) uptake occurred within minutes. Impairment was lost when the antibody was combined with the immunizing peptide. DMT1 and ferroportin undergo internalisation to late endosomes and, in the presence of the antibody, augmented internalisation of DMT1 and ferroportin caused swelling of late endosomes. Surface binding of Fe(II) and iron transport V-max were reduced by 50{\%}, indicating that the antibody removed membrane-bound DMT1. The ferroportin antibody induced rapid turnover of membrane ferroportin and DMT1 and its internalisation to late endosomes, resulting in impaired Fe(II) uptake.",
author = "Phillip Oates and Carla Thomas",
year = "2005",
doi = "10.1007/s00424-005-1421-7",
language = "English",
volume = "450",
pages = "317--325",
journal = "Pflugers Archiv-European Journal of Physiology",
issn = "0031-6768",
publisher = "Springer-Verlag London Ltd.",
number = "5",

}

TY - JOUR

T1 - Augmented internalisation of ferroportin to late endosomes impairs iron uptake by enterocyte-like IEC-6 cells

AU - Oates, Phillip

AU - Thomas, Carla

PY - 2005

Y1 - 2005

N2 - Absorption of iron occurs by duodenal enterocytes, involving uptake by the divalent metal transporter-1 (DMT1) and release by ferroportin. Ferroportin responds to the hepatocyte-produced 25-amino-acid-peptide hepcidin-25 by undergoing internalisation to late endosomes that impair iron release. Ferroportin is also expressed on the apical membrane of polarised Caco-2 cells, rat intestinal cells and in IEC-6 cells (an intestinal epithelial cell line). A blocking antibody to ferroportin also impairs the uptake, but not the release, of iron. In this study IEC-6 cells were used to study the mechanism of impairment or recovery from impairment produced by the blocking antibody and the fate of DMT1 and ferroportin. Uptake of 1 mu M Fe(II) was studied by adding the antibody from time 0 and after adding or removing the antibody once a steady state had been reached. Surface binding, maximum iron transport rate V-max and transporter affinity (K-m) were measured after impairment of iron uptake. Ferroportin and DMT1 distribution were assessed by immunofluorescence microscopy. Antibody-mediated impairment, or recovery from impairment, of Fe(II) uptake occurred within minutes. Impairment was lost when the antibody was combined with the immunizing peptide. DMT1 and ferroportin undergo internalisation to late endosomes and, in the presence of the antibody, augmented internalisation of DMT1 and ferroportin caused swelling of late endosomes. Surface binding of Fe(II) and iron transport V-max were reduced by 50%, indicating that the antibody removed membrane-bound DMT1. The ferroportin antibody induced rapid turnover of membrane ferroportin and DMT1 and its internalisation to late endosomes, resulting in impaired Fe(II) uptake.

AB - Absorption of iron occurs by duodenal enterocytes, involving uptake by the divalent metal transporter-1 (DMT1) and release by ferroportin. Ferroportin responds to the hepatocyte-produced 25-amino-acid-peptide hepcidin-25 by undergoing internalisation to late endosomes that impair iron release. Ferroportin is also expressed on the apical membrane of polarised Caco-2 cells, rat intestinal cells and in IEC-6 cells (an intestinal epithelial cell line). A blocking antibody to ferroportin also impairs the uptake, but not the release, of iron. In this study IEC-6 cells were used to study the mechanism of impairment or recovery from impairment produced by the blocking antibody and the fate of DMT1 and ferroportin. Uptake of 1 mu M Fe(II) was studied by adding the antibody from time 0 and after adding or removing the antibody once a steady state had been reached. Surface binding, maximum iron transport rate V-max and transporter affinity (K-m) were measured after impairment of iron uptake. Ferroportin and DMT1 distribution were assessed by immunofluorescence microscopy. Antibody-mediated impairment, or recovery from impairment, of Fe(II) uptake occurred within minutes. Impairment was lost when the antibody was combined with the immunizing peptide. DMT1 and ferroportin undergo internalisation to late endosomes and, in the presence of the antibody, augmented internalisation of DMT1 and ferroportin caused swelling of late endosomes. Surface binding of Fe(II) and iron transport V-max were reduced by 50%, indicating that the antibody removed membrane-bound DMT1. The ferroportin antibody induced rapid turnover of membrane ferroportin and DMT1 and its internalisation to late endosomes, resulting in impaired Fe(II) uptake.

U2 - 10.1007/s00424-005-1421-7

DO - 10.1007/s00424-005-1421-7

M3 - Article

VL - 450

SP - 317

EP - 325

JO - Pflugers Archiv-European Journal of Physiology

JF - Pflugers Archiv-European Journal of Physiology

SN - 0031-6768

IS - 5

ER -