title: Endothelin-1 reduces p-glycoprotein transport activity in an in vitro model of human adult blood-brain barrier.
abstract: OBJECTIVE
  It is a huge challenge to understand the blood-brain barrier (BBB), which is a key element in neuroinflammation associated with many brain diseases. The BBB also regulates the passage of xenobiotics into the central nervous system (CNS), and therefore influences drug efficacy. This may be due to the presence of ATP binding cassette transporters such as P-glycoprotein (Pgp) on the BBB, which are efflux pumps known to transport many drugs. The peptide endothelin 1 (ET-1) is involved in different kinds of CNS diseases and neuroinflammation, and is known to modulate Pgp transport activity. Although there are data from animal models, data from human models are scarce. We evaluated Pgp expression and transport activity in adult human brain microvascular endothelial cells (HBMECs) when exposing an adult human in vitro BBB model to ET-1.
  
  
  METHODS
  Adult HBMECs were cocultured with human adult glial cells on a Transwells to mimic blood and CNS compartments. These human in vitro BBBs were exposed for 24 h to 100 nM and 10 nM ET-1. Pgp expression was assessed by flow cytometry and its transport activity by measuring radiolabelled digoxin passage.
  
  
  RESULTS
  After exposure to ET-1, flow cytometry showed no shift of fluorescence intensity for a Pgp specific antibody. The passage of digoxin increased with a significant decrease of Q ratio for 10 nM ET-1.
  
  
  CONCLUSIONS
  Our results show that ET-1 has no effect on Pgp expression of adult HBMECs, but does modulate Pgp transport activity.
authors: iBiTec-S (Institut de biologie et technologies de Saclay), SPI (Service de Pharmacologie et Immunoanalyse), LEMM (Laboratoire d'Etudes du Métabolisme des Médicaments), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. alexandra.hembury@cea.fr
authors: Alexandra
authors: A
authors: Hembury
authors: Aloïse
authors: A
authors: Mabondzo
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects / Q000378:metabolism*; D000367:Age Factors; D000918:Antibody Specificity; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D018920:Coculture Techniques; D004077:Digoxin / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D019332:Endothelin-1 / Q000494:pharmacology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D008954:Models, Biological; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D019332:Endothelin-1; D004077:Digoxin