title: Regulatory effects of tumor necrosis factor-alpha and interleukin-6 on HAMP expression in iron loaded rat hepatocytes.
abstract: OBJECTIVE
  To study the effect of iron and proinflammatory cytokines on the expression of HAMP and other iron regulatory genes in primary rat hepatocytes.
  
  
  METHODS
  Primary hepatocytes from rats fed a control or iron-enriched diet were plated on extracellular matrix and incubated with inflammatory stimuli in the presence or absence of serum. Cells were also incubated with desferrioxamine or ferric ammonium citrate. mRNA levels were determined by Real-Time PCR.
  
  
  RESULTS
  Hepatocytes from control rats increased their HAMP expression during culturing, whereas the opposite was seen in hepatocytes from carbonyl-iron loaded animals. In the presence of serum, tumor necrosis factor-alpha, lipopolysaccharide and interleukin-6 increased HAMP expression in hepatocytes from both control and iron-loaded rats. Under serum-free conditions only tumor necrosis factor-alpha increased HAMP mRNA levels. Desferrioxamine and ferric ammonium citrate decreased HAMP gene expression. Tumor necrosis factor-alpha significantly increased mRNA levels of TfR2 and decreased those of DMT1 and IREG1.
  
  
  CONCLUSIONS
  HAMP expression differs in cultured as compared with freshly isolated hepatocytes, and decreases in iron-loaded hepatocytes in serum free-media, suggesting that additional serum factors influence HAMP expression. Tumor necrosis factor-alpha regulates the mRNA levels of HAMP, IREG1, DMT1 and TfR2 in cultured hepatocytes from both iron-loaded and control animals.
authors.affiliation: Department of Gastroenterology and Hepatology, Karolinska Institutet, Karolinska University Hospital Solna, 171 76 Stockholm, Sweden.
authors.forename: Vijole
authors.initials: V
authors.lastname: Dzikaite
authors.forename: Petra
authors.initials: P
authors.lastname: Holmström
authors.forename: Per
authors.initials: P
authors.lastname: Stål
authors.forename: Kristina
authors.initials: K
authors.lastname: Eckes
authors.forename: Karin
authors.initials: K
authors.lastname: Hagen
authors.forename: Gösta
authors.initials: G
authors.lastname: Eggertsen
authors.forename: Mats
authors.initials: M
authors.lastname: Gåfvels
authors.forename: Ojar
authors.initials: O
authors.lastname: Melefors
authors.forename: Rolf
authors.initials: R
authors.lastname: Hultcrantz
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D004195:Disease Models, Animal; D015870:Gene Expression / Q000187:drug effects*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D064451:Hepcidins; D066298:In Vitro Techniques; D015850:Interleukin-6 / Q000494:pharmacology*; D019190:Iron Overload / Q000378:metabolism* / Q000473:pathology; D008297:Male; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D023181:Antimicrobial Cationic Peptides; C578703:Hamp protein, rat; D064451:Hepcidins; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha