Abstract
Missense mutations in the ferroportin gene (SLC11A3) result in haemochromatosis type 4 [HFE4, Online Mendelian Inheritance in Man (OMIM) reference 606069] or ferroportin disease, an autosomal dominant disorder characterized by predominantly reticuloendothelial iron accumulation. To verify whether HFE4 is caused by defective iron recycling because of loss of functionality of ferroportin, we down-regulated SLC11A gene expression in human macrophages by using small interfering RNAs (siRNAs). Transfection experiments with ferroportin siRNAs resulted in a marked reduction (about two-thirds on average) in ferroportin mRNA levels as detected by quantitative real time polymerase chain reaction. When macrophages were grown in medium supplemented with iron, cells transfected with siRNAs displayed three- to eightfold increases in staining intensities following Perls reaction. These macrophages also showed significant increases in H-ferritin content. The observation that ferroportin mRNA down-regulation to levels compatible with haplo-insufficiency causes increased iron retention and H-ferritin synthesis in cultured macrophages has important implications. First, this indicates that ferroportin levels must be finely regulated in order to maintain cellular iron homeostasis, and that both copies of SLC11A3 must function efficiently to prevent iron accumulation. Second, this observation supports the hypothesis that reticuloendothelial iron overload in patients with ferroportin disease is caused by loss-of-function mutations in the SLC11A3 gene that mainly impair macrophage iron recycling.
| Original language | English |
|---|---|
| Pages (from-to) | 598-603 |
| Number of pages | 6 |
| Journal | British Journal of Haematology |
| Volume | 127 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Dec 2004 |
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Keywords
- Ferroportin
- Haemochromatosis
- Iron
- Macrophage
- Reticuloendothelial cell
ASJC Scopus subject areas
- Hematology
Cite this
Ferroportin gene silencing induces iron retention and enhances ferritin synthesis in human macrophages. / Gallí, Anna; Bergamaschi, Gaetano; Recalde, Helios; Biasiotto, Giorgio; Santambrogio, Paolo; Boggi, Sabrina; Levi, Sonia; Arosio, Paolo; Cazzola, Mario.
In: British Journal of Haematology, Vol. 127, No. 5, 12.2004, p. 598-603.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Ferroportin gene silencing induces iron retention and enhances ferritin synthesis in human macrophages
AU - Gallí, Anna
AU - Bergamaschi, Gaetano
AU - Recalde, Helios
AU - Biasiotto, Giorgio
AU - Santambrogio, Paolo
AU - Boggi, Sabrina
AU - Levi, Sonia
AU - Arosio, Paolo
AU - Cazzola, Mario
PY - 2004/12
Y1 - 2004/12
N2 - Missense mutations in the ferroportin gene (SLC11A3) result in haemochromatosis type 4 [HFE4, Online Mendelian Inheritance in Man (OMIM) reference 606069] or ferroportin disease, an autosomal dominant disorder characterized by predominantly reticuloendothelial iron accumulation. To verify whether HFE4 is caused by defective iron recycling because of loss of functionality of ferroportin, we down-regulated SLC11A gene expression in human macrophages by using small interfering RNAs (siRNAs). Transfection experiments with ferroportin siRNAs resulted in a marked reduction (about two-thirds on average) in ferroportin mRNA levels as detected by quantitative real time polymerase chain reaction. When macrophages were grown in medium supplemented with iron, cells transfected with siRNAs displayed three- to eightfold increases in staining intensities following Perls reaction. These macrophages also showed significant increases in H-ferritin content. The observation that ferroportin mRNA down-regulation to levels compatible with haplo-insufficiency causes increased iron retention and H-ferritin synthesis in cultured macrophages has important implications. First, this indicates that ferroportin levels must be finely regulated in order to maintain cellular iron homeostasis, and that both copies of SLC11A3 must function efficiently to prevent iron accumulation. Second, this observation supports the hypothesis that reticuloendothelial iron overload in patients with ferroportin disease is caused by loss-of-function mutations in the SLC11A3 gene that mainly impair macrophage iron recycling.
AB - Missense mutations in the ferroportin gene (SLC11A3) result in haemochromatosis type 4 [HFE4, Online Mendelian Inheritance in Man (OMIM) reference 606069] or ferroportin disease, an autosomal dominant disorder characterized by predominantly reticuloendothelial iron accumulation. To verify whether HFE4 is caused by defective iron recycling because of loss of functionality of ferroportin, we down-regulated SLC11A gene expression in human macrophages by using small interfering RNAs (siRNAs). Transfection experiments with ferroportin siRNAs resulted in a marked reduction (about two-thirds on average) in ferroportin mRNA levels as detected by quantitative real time polymerase chain reaction. When macrophages were grown in medium supplemented with iron, cells transfected with siRNAs displayed three- to eightfold increases in staining intensities following Perls reaction. These macrophages also showed significant increases in H-ferritin content. The observation that ferroportin mRNA down-regulation to levels compatible with haplo-insufficiency causes increased iron retention and H-ferritin synthesis in cultured macrophages has important implications. First, this indicates that ferroportin levels must be finely regulated in order to maintain cellular iron homeostasis, and that both copies of SLC11A3 must function efficiently to prevent iron accumulation. Second, this observation supports the hypothesis that reticuloendothelial iron overload in patients with ferroportin disease is caused by loss-of-function mutations in the SLC11A3 gene that mainly impair macrophage iron recycling.
KW - Ferroportin
KW - Haemochromatosis
KW - Iron
KW - Macrophage
KW - Reticuloendothelial cell
UR - http://www.scopus.com/inward/record.url?scp=10344246056&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=10344246056&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2141.2004.05238.x
DO - 10.1111/j.1365-2141.2004.05238.x
M3 - Article
C2 - 15566364
AN - SCOPUS:10344246056
VL - 127
SP - 598
EP - 603
JO - British Journal of Haematology
JF - British Journal of Haematology
SN - 0007-1048
IS - 5
ER -