title: Rescuing iron-overloaded macrophages by conservative relocation of the accumulated metal.
abstract: OBJECTIVE
  Systemic iron deficiency concomitant with macrophage iron retention is characteristic of iron-refractory anaemias associated with chronic disease. The systemic misdistribution of iron, which is further exacerbated by parenteral iron supplementation, is mainly attributable to iron retention exerted on resident macrophages by hepcidin-mediated down-regulation of the iron exporter ferroportin. We aimed at developing an experimental macrophage-based cell model that recapitulates pathophysiological features of iron misdistribution found in chronic disorders and use it as a screening platform for identifying agents with the potential for relocating the accumulated metal and restoring affected functions.
  
  
  METHODS
  A raw macrophage subline was selected as cell model of iron retention based on their capacity to take up polymeric iron or aged erythrocytes excessively, resulting in a demonstrable increase of cell labile iron pools and oxidative damage that are aggravated by hepcidin.
  
  
  RESULTS
  This model provided a three-stage high throughput screening platform for identifying agents with the combined ability to: (i) scavenge cell iron and thereby rescue macrophage cells damaged by iron-overload; (ii) bypass the ferroportin blockade by conveying the scavenged iron to other iron-starved cells in co-culture via transferrin but (iii) without promoting utilization of the scavenged iron by intracellular pathogens. As test agents we used chelators in clinical practice and found the oral chelator deferiprone fulfilled essentially all of the three criteria.
  
  
  CONCLUSIONS
  We provide a proof of principle for conservative iron relocation as complementary therapeutic approach for correcting the misdistribution of iron associated with chronic disease and exacerbated by parenteral iron supplementation.
authors.affiliation: Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond Safra Campus at Givat Ram, Jerusalem, Israel.
authors.forename: Yang-Sung
authors.initials: YS
authors.lastname: Sohn
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Mitterstiller
authors.forename: William
authors.initials: W
authors.lastname: Breuer
authors.forename: Guenter
authors.initials: G
authors.lastname: Weiss
authors.forename: Z Ioav
authors.initials: ZI
authors.lastname: Cabantchik
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000188:drug therapy / Q000378:metabolism; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D027682:Cation Transport Proteins / Q000378:metabolism; D002478:Cells, Cultured; D018920:Coculture Techniques; D000077543:Deferiprone; D004705:Endocytosis / Q000502:physiology; D004912:Erythrocytes / Q000378:metabolism; D064451:Hepcidins; D006801:Humans; D007501:Iron / Q000097:blood / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000494:pharmacology; D019190:Iron Overload / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism*; D020014:K562 Cells; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D018384:Oxidative Stress / Q000502:physiology; D011728:Pyridones / Q000494:pharmacology; D014168:Transferrin / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000098742:Ferroportin
chemical_list: D023181:Antimicrobial Cationic Peptides; D027682:Cation Transport Proteins; C578702:HAMP protein, human; C579599:Hamp protein, mouse; D064451:Hepcidins; D007502:Iron Chelating Agents; D011728:Pyridones; D014168:Transferrin; D000098742:Ferroportin; D000077543:Deferiprone; D007501:Iron