title: Fatty Acid Binding Proteins Expressed at the Human Blood-Brain Barrier Bind Drugs in an Isoform-Specific Manner.
abstract: OBJECTIVE
  To examine the expression of fatty acid binding proteins (FABPs) at the human blood-brain barrier (BBB) and to assess their ability to bind lipophilic drugs.
  
  
  METHODS
  mRNA and protein expression of FABP subtypes in immortalized human brain endothelial (hCMEC/D3) cells were examined by RT-qPCR and Western blot, respectively. FABPs that were found in hCMEC/D3 cells (hFABPs) were recombinantly expressed and purified from Escherichia coli C41(DE3) cells. Drug binding to these hFABPs was assessed using a fluorescence assay, which measured the ability of a panel of lipophilic drugs to displace the fluorescent probe compound 1-anilinonaphthalene-8-sulfonic acid (ANS).
  
  
  RESULTS
  hFABP3, 4 and 5 were expressed in hCMEC/D3 cells at the mRNA and protein level. The competitive ANS displacement assay demonstrated that, in general, glitazones preferentially bound to hFABP5 (Ki: 1.0-28 μM) and fibrates and fenamates preferentially bound to hFABP4 (Ki: 0.100-17 μM). In general, lipophilic drugs appeared to show weaker affinities for hFABP3 relative to hFABP4 and hFABP5. No clear correlation was observed between the molecular structure or physicochemical properties of the drugs and their ability to displace ANS from hFABP3, 4 and 5.
  
  
  CONCLUSIONS
  hFABP3, 4 and 5 are expressed at the human BBB and bind differentially to a diverse range of lipophilic drugs. The unique expression and binding patterns of hFABPs at the BBB may therefore influence drug disposition into the brain.
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences,, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Gordon S
authors.initials: GS
authors.lastname: Lee
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences,, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Katharina
authors.initials: K
authors.lastname: Kappler
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences,, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Christopher J H
authors.initials: CJ
authors.lastname: Porter
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Scanlon
authors.affiliation: Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences,, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia. joseph.nicolazzo@monash.edu.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Nicolazzo
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D001812:Blood-Brain Barrier / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D042783:Endothelial Cells / Q000378:metabolism; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism*; D054361:Fenamates / Q000378:metabolism; D058607:Fibric Acids / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology*; D020033:Protein Isoforms / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D045162:Thiazolidinediones / Q000378:metabolism
chemical_list: D000817:Anilino Naphthalenesulfonates; D050556:Fatty Acid-Binding Proteins; D054361:Fenamates; D058607:Fibric Acids; D005456:Fluorescent Dyes; D004364:Pharmaceutical Preparations; D020033:Protein Isoforms; D012333:RNA, Messenger; D045162:Thiazolidinediones; C027132:1-anilino-8-naphthalenesulfonate
keywords: blood–brain barrier; drug binding; expression profiles; fatty acid binding proteins; fluorescence displacement