title: A novel model for brain iron uptake: introducing the concept of regulation.
abstract: Neurologic disorders such as Alzheimer's, Parkinson's disease, and Restless Legs Syndrome involve a loss of brain iron homeostasis. Moreover, iron deficiency is the most prevalent nutritional concern worldwide with many associated cognitive and neural ramifications. Therefore, understanding the mechanisms by which iron enters the brain and how those processes are regulated addresses significant global health issues. The existing paradigm assumes that the endothelial cells (ECs) forming the blood-brain barrier (BBB) serve as a simple conduit for transport of transferrin-bound iron. This concept is a significant oversimplification, at minimum failing to account for the iron needs of the ECs. Using an in vivo model of brain iron deficiency, the Belgrade rat, we show the distribution of transferrin receptors in brain microvasculature is altered in luminal, intracellular, and abluminal membranes dependent on brain iron status. We used a cell culture model of the BBB to show the presence of factors that influence iron release in non-human primate cerebrospinal fluid and conditioned media from astrocytes; specifically apo-transferrin and hepcidin were found to increase and decrease iron release, respectively. These data have been integrated into an interactive model where BBB ECs are central in the regulation of cerebral iron metabolism.
authors.affiliation: Department of Neural and Behavioral Sciences, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Simpson
authors.affiliation: Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA.
authors.forename: Padmavathi
authors.initials: P
authors.lastname: Ponnuru
authors.affiliation: Department of Neural and Behavioral Sciences, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA.
authors.forename: Marianne E
authors.initials: ME
authors.lastname: Klinger
authors.affiliation: Department of Neural and Behavioral Sciences, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA.
authors.forename: Roland L
authors.initials: RL
authors.lastname: Myers
authors.affiliation: Department of Neural and Behavioral Sciences, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA.
authors.forename: Kavi
authors.initials: K
authors.lastname: Devraj
authors.affiliation: Harlow Center for Biological Psychology, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Coe
authors.affiliation: Harlow Center for Biological Psychology, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Gabriele R
authors.initials: GR
authors.lastname: Lubach
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Carruthers
authors.affiliation: 1] Department of Neural and Behavioral Sciences, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA [2] Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Connor
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001059:Apoproteins / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism; D001692:Biological Transport; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism; D005260:Female; D064451:Hepcidins / Q000378:metabolism; D006579:Heterozygote; D006720:Homozygote; D007501:Iron / Q000134:cerebrospinal fluid / Q000378:metabolism*; D008253:Macaca mulatta; D008297:Male; D055806:Microvessels / Q000378:metabolism; D008954:Models, Biological; D017207:Rats, Sprague-Dawley; D011990:Receptors, Transferrin / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism
chemical_list: D001059:Apoproteins; D064451:Hepcidins; D011990:Receptors, Transferrin; D014168:Transferrin; C028284:apotransferrin; D007501:Iron