Overexpression of H Ferritin and Up-regulation of Iron Regulatory Protein Genes during Differentiation of 3T3-L1 Pre-adipocytes

The role of iron-dependent oxidative metabolism in protecting the oxidable substrates contained in mature adipocytes is still unclear. Because differentiation increases ferritin formation in several cell types, thereby leading to an accumulation of H-rich isoferritins, we investigated whether differ...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2000-11, Vol.275 (47), p.36708-36712
Main Authors: Festa, Michela, Ricciardelli, Gaetano, Mele, Guido, Pietropaolo, Concetta, Ruffo, Alfredo, Colonna, Alfredo
Format: Article
Language:English
Subjects:
3T3 Cells
Adipocytes - cytology
adipose tissue
Animals
Blotting, Northern
Cell Differentiation - genetics
Cytokines - biosynthesis
dexamethasone
Electrophoresis, Polyacrylamide Gel
Ferritins - biosynthesis
iron regulatory protein
Iron Regulatory Protein 1
Iron-Regulatory Proteins
Iron-Sulfur Proteins - biosynthesis
Iron-Sulfur Proteins - genetics
isobutylmethylxanthine
Mice
RNA, Messenger - metabolism
RNA-Binding Proteins - biosynthesis
RNA-Binding Proteins - genetics
Up-Regulation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The role of iron-dependent oxidative metabolism in protecting the oxidable substrates contained in mature adipocytes is still unclear. Because differentiation increases ferritin formation in several cell types, thereby leading to an accumulation of H-rich isoferritins, we investigated whether differentiation affects iron metabolism in 3T3-L1 pre-adipocytes. To this aim, we evaluated the expression of the genes coding for the H and L ferritin subunits and for cytoplasmic iron regulatory protein (IRP) during the differentiation of 3T3-L1 cells in adipocytes induced by the addition of isobutylmethylxanthine, insulin, and dexamethasone. Differentiation enhanced ferritin formation and caused overexpression of the H subunit, thus altering the H/L subunit ratio. Northern blot analysis showed increased levels of H subunit mRNA. A gel retardation assay of cytoplasmic extract from differentiated cells, using an iron-responsive element as a probe, revealed enhanced an RNA binding capacity of IRP1, which correlated with the increase of IRP1 mRNA. The observed correlation between differentiation and iron metabolism in adipocytes suggests that an accumulation of H-rich isoferritin may limit the toxicity of iron in adipose tissue, thus exerting an antioxidant function.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M004988200