Regulation of ferritin expression by alcohol in a human hepatoblastoma cell line and in rat hepatocyte cultures

Serum ferritin increases in chronic alcoholism, without clear explanation. We have previously shown that alcohol increases ferritin levels in a human hepatoblastoma cell line (HepG2). The aims of the present work were: 1) To extend our results in normal rat hepatocyte cultures, and 2) To determine the mechanism by which alcohol enhances ferritin levels. In HepG2 cells, high alcohol concentrations (300 mM) during long exposure (4 days) increased the synthesis of H and L ferritin subunits, in association with increased levels of ferritin mRNAs. In rat hepatocyte cultures, the synthesis of L ferritin increased after 24 h of exposure to lower alcohol concentrations (10 mM); alcohol had no effect on ferritin mRNAs levels. In both cell types, the alcohol effect was not related to an increase in iron intracellular incorporation. In HepG2 cells, desferrioxamine (Df), a potent iron chelator, abolished ferritin synthesis in the presence or absence of alcohol, and abolished the alcohol induction of ferritin mRNAs. In rat hepatocytes, Df decreased ferritin synthesis to a similar level in the presence or absence of alcohol. Alcohol increased ferritin synthesis differently in HepG2 cells and in normal rat hepatocyte cultures. In the latter case, the alcohol effect was observed at low concentration. Despite a striking inhibiting effect of Df on ferritin synthesis, in both cellular models a mechanism accounting for increased ferritin synthesis independently of iron is suggested. Globally, these data strongly suggest that hyperferritinemia in chronic alcoholism could be related to the induction of ferritin by alcohol.