TNF, IFN-gamma, and endotoxin increase expression of DMT1 in bronchial epithelial cells.
Regulation of the metal transport protein divalent metal transporter-1 (DMT1) may contribute to the uptake and detoxification of iron by cells resident in the respiratory tract. Inflammation has been associated with an increased availability of this metal resulting in an oxidative stress. Because proinflammatory cytokines and LPS have been demonstrated to affect an elevated expression of DMT1 in a macrophage cell line, we tested the hypothesis that tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and LPS increase DMT1 expression in airway epithelial cells. We used RT-PCR to detect mRNA for both -IRE DMT1 and +IRE DMT1 in BEAS-2B cells. Treatment with TNF-alpha, IFN-gamma, or LPS increased both forms. Western blot analysis also demonstrated an increase in the expression of both isoforms of DMT1 after these treatments. Twenty-four hours after exposure of an animal model to TNF-alpha, IFN-gamma, or LPS, a significant increase in pulmonary expression of -IRE DMT1 was seen by immunohistochemistry; the level of +IRE DMT1 was too low in the lung to be visualized using this methodology. Finally, iron transport into BEAS-2B cells was increased after inclusion of TNF-alpha, IFN-gamma, or LPS in the media. We conclude that proinflammatory cytokines and LPS increase mRNA and protein expression of DMT1 in airway cells in vitro and in vivo. Furthermore, both -IRE and +IRE isoforms are elevated after exposures. Increased expression of this protein appears to be included in a coordinated response of the cell and tissue where the function might be to diminish availability of metal.
Wang
Xinchao
X
Center for Environmental Medicine and Lung Biology, University of North Carolina, Chapel Hill, USA.
Garrick
Michael D
MD
Yang
Funmei
F
Dailey
Lisa A
LA
Piantadosi
Claude A
CA
Ghio
Andrew J
AJ
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000096:biosynthesis*; D002461:Cell Line, Transformed; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007501:Iron / Q000378:metabolism; D033862:Iron-Binding Proteins / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D020033:Protein Isoforms / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D000099236:Solute Carrier Family 11, Member 2
D027682:Cation Transport Proteins; D007371:Interferon-gamma; D007501:Iron; D033862:Iron-Binding Proteins; D008070:Lipopolysaccharides; D020033:Protein Isoforms; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000099236:Solute Carrier Family 11, Member 2; C482199:lipopolysaccharide, E coli O55-B5