Iron up-modulates the expression of transferrin receptors during monocyte-macrophage maturation

摘要: Abstract We have investigated the effect of iron on expression transferrin receptors (TrfRs) and ferritin chains in cultures human peripheral blood monocytes maturing to macrophages. Monocyte-macrophage maturation is associated with a gradual rise Trf-binding capacity absence cell proliferation. At all culture times, treatment ferric ammonium citrate induces dose-dependent level as compared nontreated cells. Scatchard analysis revealed that this phenomenon due an increase receptor number rather than alteration ligand-receptor affinity. Biosynthesis experiments indicated TrfRs synthesis, which sustained elevation TrfR RNA level. The up-regulation synthesis specific other macrophage membrane proteins not affected by addition. Conversely, addition chelator induced slight decrease synthesis. heavy light at protein levels was markedly more elevated cultured macrophages fresh monocytes, thus suggesting modulation genes transcriptional or post-transcriptional levels. Addition salts monocyte-macrophage sharply stimulated but only slightly enhanced RNA, indicating translational These results suggests monocytes-macrophages, up-regulates expression, sharp contrast negative feedback reported variety types. observations may shed mechanism(s) storage tissue under normal conditions possibly pathogenesis diseases characterized abnormal storage.