title: The multidrug-resistance P-glycoprotein (Pgp, MDR1) is an early marker of blood-brain barrier development in the microvessels of the developing human brain.
abstract: The multidrug-resistance P-glycoprotein (Pgp) was initially identified as an energy-dependent proton pump, which transports a variety of non-related compounds out of chemotherapy-resistant cancer cells. Molecular biological investigations using knockout mice for the mouse homologue of the human Pgp showed that these mice partially lack a functioning blood-brain barrier, indicating that Pgp has an important role in the blood-brain barrier as its normal function. The presence of Pgp expression in formalin-fixed and wax-processed tissue sections can be assessed using the monoclonal antibody, JSB-1. Since no data on the developmental expression of Pgp are available, we stained a developmental series of human brain sections with JSB-1. Our results indicate that Pgp expression in endothelia of brain microvessels occurs regularly in embryos of about 30-mm crown-rump length (CRL). Strong reactivity is seen in blood vessels of fetuses from 123-mm CRL. There is also reactivity in pial blood vessels but not in choroid plexus blood vessels known to be without a blood-brain barrier. Pgp expression is therefore an early marker of the blood-brain barrier in the developing human brain.
authors.affiliation: University of Southampton, United Kingdom. us@soton.ac.uk
authors.forename: U
authors.initials: U
authors.lastname: Schumacher
authors.forename: K
authors.initials: K
authors.lastname: Mollgård
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis / Q000235:genetics*; D000911:Antibodies, Monoclonal; D015415:Biomarkers; D001812:Blood-Brain Barrier / Q000502:physiology*; D001921:Brain / Q000098:blood supply / Q000196:embryology / Q000378:metabolism*; D019450:Genes, MDR; D006801:Humans; D007150:Immunohistochemistry; D008833:Microcirculation / Q000502:physiology; D016612:Paraffin Embedding
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000911:Antibodies, Monoclonal; D015415:Biomarkers