Evolutionary conservation of vertebrate blood-brain barrier chemoprotective mechanisms in Drosophila.
Pharmacologic remedy of many brain diseases is difficult because of the powerful drug exclusion properties of the blood-brain barrier (BBB). Chemical isolation of the vertebrate brain is achieved through the highly integrated, anatomically compact and functionally overlapping chemical isolation processes of the BBB. These include functions that need to be coordinated between tight diffusion junctions and unidirectionally acting xenobiotic transporters. Understanding of many of these processes has been hampered, because they are not well mimicked by ex vivo models of the BBB and have been experimentally difficult and expensive to disentangle in intact rodent models. Here we show that the Drosophila melanogaster (Dm) humoral/CNS barrier conserves the xenobiotic exclusion properties found in the vertebrate vascular endothelium. We characterize a fly ATP binding cassette (ABC) transporter, Mdr65, that functions similarly to mammalian xenobiotic BBB transporters and show that varying its levels solely in the Dm BBB changes the inherent sensitivity of the barrier to cytotoxic pharmaceuticals. Furthermore, we demonstrate orthologous function between Mdr65 and vertebrate ABC transporters by rescuing chemical protection of the Dm brain with human MDR1/Pgp. These data indicate that the ancient origins of CNS chemoprotection extend to both conserved molecular means and functionally analogous anatomic spaces that together promote CNS selective drug partition. Thus, Dm presents an experimentally tractable system for analyzing physiological properties of the BBB in an intact organism.
Mayer
Fahima
F
Department of Anesthesia and Perioperative Care, San Francisco General Hospital, and Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94143, USA.
Mayer
Nasima
N
Chinn
Leslie
L
Pinsonneault
Robert L
RL
Kroetz
Deanna
D
Bainton
Roland J
RJ
D018435:ATP Binding Cassette Transporter, Subfamily B / Q000378:metabolism; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism*; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D016503:Drug Delivery Systems; D019143:Evolution, Molecular; D006801:Humans; D018696:Neuroprotective Agents / Q000378:metabolism*
C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D029721:Drosophila Proteins; D018696:Neuroprotective Agents; C069936:mdr65 protein, Drosophila