title: Iron Regulates Apolipoprotein E Expression and Secretion in Neurons and Astrocytes.
abstract: BACKGROUND
  There is strong evidence that iron homeostasis is impaired in the aging and Alzheimer's disease (AD) brain and that this contributes to neurodegeneration. Apolipoprotein E (APOE) has been identified as the strongest genetic risk factor for AD. However, the interaction between the two has yet to be fully explored.
  
  
  OBJECTIVE
  This study aimed to investigate the relationship between exogenous iron levels and ApoE in neurons and astrocytes.
  
  
  METHODS
  Our study used primary cultured cortical neurons and astrocytes to investigate the changes in ApoE caused by iron. Western blot and RT-PCR were used to measure ApoE.
  
  
  RESULTS
  We observed that iron upregulated intracellular ApoE levels in both neurons and astrocytes at the post-transcriptional and transcriptional level, respectively. However, there was less full-length ApoE secreted by neurons and astrocytes after iron treatment. We speculate that this might impair brain lipid metabolism and amyloid-β clearance. In terms of ApoE receptors, we observed that neuronal LRP-1 levels were increased by the addition of exogenous iron, which could contribute to AβPP endocytosis in neurons. However, there were no significant changes in neuronal LDLR, astrocyte LDLR, or astrocyte LRP-1.
  
  
  CONCLUSIONS
  Our study reveals that iron may contribute to the pathogenesis of AD by affecting ApoE and its receptors and supports the notion that iron chelation should be investigated as a therapeutic strategy for AD.
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.|The Department of Tissue Engineering, School of Fundamental Science, China Medical University, Shenyang North New Area, Shenyang, Liaoning Province, P.R. China.
authors.forename: He
authors.initials: H
authors.lastname: Xu
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Perreau
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
authors.forename: Krista A
authors.initials: KA
authors.lastname: Dent
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
authors.forename: Ashley I
authors.initials: AI
authors.lastname: Bush
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
authors.forename: David I
authors.initials: DI
authors.lastname: Finkelstein
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Adlard
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D001057:Apolipoproteins E / Q000378:metabolism*; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D005293:Ferritins / Q000378:metabolism; D007150:Immunohistochemistry; D007501:Iron / Q000378:metabolism*; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D011973:Receptors, LDL / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D015032:Zinc / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D001057:Apolipoproteins E; D026503:Low Density Lipoprotein Receptor-Related Protein-1; C486645:Lrp1 protein, mouse; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D011973:Receptors, LDL; D025521:Tumor Suppressor Proteins; D003300:Copper; D005293:Ferritins; D007501:Iron; D015032:Zinc
keywords: Apolipoprotein E; iron; lipoprotein receptor-related protein; low-density lipoprotein receptor