|
|
||||||||
and IL-1
on iron metabolism by A549
cells and influence on cytotoxicity
Department of Medicine, Kansas City Veterans Affairs Medical Center, Kansas City, Missouri 64128; Division of Pulmonary and Critical Care Medicine and Division of Hematology, Department of Medicine, and Division of Plastic Surgery, Department of Surgery, University of Kansas School of Medicine, Kansas City, Kansas 66160
Extracellular iron, which is predominantly bound
by transferrin, is present in low concentrations within alveolar
structures, and concentrations are increased in various pulmonary
disorders. Iron accumulation by cells can promote oxidative injury.
However, the synthesis of ferritin stimulated by metal exposure for
intracellular iron storage is normally protective. The cytokines tumor
necrosis factor (TNF)-
and interleukin (IL)-1
may alter iron
metabolism by alveolar cells. In this study, we assessed the effects of
TNF-
and IL-1
on iron metabolism with a cell line with properties of type 2 alveolar epithelial cells (A549) exposed to
non-transferrin-bound (NTBI;
FeSO4) or transferrin-bound
(TBI) iron. In addition, we assessed the cytotoxicity of these
exposures by measuring the cell accumulation of malondialdehyde (MDA),
a product of lipid peroxidation, and cell death (MTT assay and lactate
dehydrogenase release). A549 cells treated with NTBI or TBI in
concentrations up to 40 µM accumulated iron and synthesized
predominantly L-type ferritin without accumulation of MDA or cell
death. Treatment of A549 cells with TNF-
(20 ng) or IL-1
(20 ng)
decreased cell transferrin-receptor expression and induced synthesis of
H-type ferritin. TNF-
and IL-1
decreased the uptake of TBI;
however, the uptake of NTBI was increased. Both cytokines enhanced
total ferritin synthesis (H plus L types) in response to iron
treatments due to enhanced synthesis of H-type ferritin. Coexposure to
TNF-
and NTBI, but not to TBI, induced MDA accumulation and greater cytotoxicity (MTT and lactate dehydrogenase release) than TNF-
alone. These findings indicate that TNF-
and IL-1
modulate iron uptake by A549 cells, with differing effects on TBI and NTBI, as well
as on H-ferritin synthesis. Enhanced iron uptake induced by TNF-
and
NTBI was also associated with increased cytotoxicity to A549 cells.
tumor necrosis factor-
; interleukin-1
; iron; ferritin; alveolar epithelium
This article has been cited by other articles:
![]() |
X. Wang, M. D. Garrick, F. Yang, L. A. Dailey, C. A. Piantadosi, and A. J. Ghio TNF, IFN-{gamma}, and endotoxin increase expression of DMT1 in bronchial epithelial cells Am J Physiol Lung Cell Mol Physiol, July 1, 2005; 289(1): L24 - L33. [Abstract] [Full Text] [PDF] |
||||
![]() |
K.-y. Yeh, M. Yeh, and J. Glass Hepcidin regulation of ferroportin 1 expression in the liver and intestine of the rat Am J Physiol Gastrointest Liver Physiol, March 1, 2004; 286(3): G385 - G394. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. M. Torti and S. V. Torti Regulation of ferritin genes and protein Blood, May 15, 2002; 99(10): 3505 - 3516. [Full Text] [PDF] |
||||
![]() |
E. W. Oppenheim, C. Adelman, X. Liu, and P. J. Stover Heavy Chain Ferritin Enhances Serine Hydroxymethyltransferase Expression and de Novo Thymidine Biosynthesis J. Biol. Chem., June 1, 2001; 276(23): 19855 - 19861. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |