title: Serum-induced up-regulation of hepcidin expression involves the bone morphogenetic protein signaling pathway.
abstract: Hepcidin is a peptide hormone that is secreted by the liver and that functions as the central regulator of systemic iron metabolism in mammals. Its expression is regulated at the transcriptional level by changes in iron status and iron requirements, and by inflammatory cues. There is considerable interest in understanding the mechanisms that influence hepcidin expression because dysregulation of hepcidin production is associated with a number of disease states and can lead to iron overload or iron-restricted anemia. In order to shed light on the factors that alter hepcidin expression, we carried out experiments with HepG2 and HuH7, human hepatoma cell lines that are widely used for this purpose. We found that the addition of heat-inactivated fetal calf serum to these cells resulted in a significant dose- and time-dependent up-regulation of hepcidin expression. Serum also activated signaling events known to be downstream of bone morphogenetic proteins (BMPs), a group of molecules that have been implicated previously in hepcidin regulation. Inhibition of these signals with dorsomorphin significantly suppressed serum-induced hepcidin up-regulation. Our results indicate that a BMP or BMP-like molecule present in serum may play an important role in regulating hepcidin expression.
authors.affiliation: Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Nanda Kumar N
authors.initials: NK
authors.lastname: Shanmugam
authors.forename: Bobby J
authors.initials: BJ
authors.lastname: Cherayil
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000097:blood*; D002417:Cattle; D056945:Hep G2 Cells; D064451:Hepcidins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D008099:Liver / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D050796:STAT3 Transcription Factor / Q000378:metabolism; D044967:Serum / Q000378:metabolism*; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D019485:Bone Morphogenetic Proteins; C578702:HAMP protein, human; D064451:Hepcidins; D011720:Pyrazoles; D011743:Pyrimidines; D050796:STAT3 Transcription Factor; D051785:Smad Proteins; C516138:dorsomorphin
keywords: BMP; DMSO; Hepatocyte; Hepcidin; Iron metabolism; RIPA; SMAD; STAT3; Serum; bone morphogenetic protein; dimethylsulfoxide; qRT-PCR; quantitative RT-PCR; radioimmunoprecipitation assay; signal transducer and activator of transcription 3; similar to mothers against decapentaplegic