title: Induction of P-glycoprotein by antiretroviral drugs in human brain microvessel endothelial cells.
abstract: The membrane-associated drug transporter P-glycoprotein (P-gp) plays an essential role in drug efflux from the brain. Induction of this protein at the blood-brain barrier (BBB) could further affect the ability of a drug to enter the brain. At present, P-gp induction mediated by antiretroviral drugs at the BBB has not been fully investigated. Since P-gp expression is regulated by ligand-activated nuclear receptors, i.e., human pregnane X receptor (hPXR) and human constitutive androstane receptor (hCAR), these receptors could represent potential pathways involved in P-gp induction by antiretroviral drugs. The aims of this study were (i) to determine whether antiretroviral drugs currently used in HIV pharmacotherapy are ligands for hPXR or hCAR and (ii) to examine P-gp function and expression in human brain microvessel endothelial cells treated with antiretroviral drugs identified as ligands of hPXR and/or hCAR. Luciferase reporter gene assays were performed to examine the activation of hPXR and hCAR by antiretroviral drugs. The hCMEC/D3 cell line, which is known to display several morphological and biochemical properties of the BBB in humans, was used to examine P-gp induction following 72 h of exposure to these agents. Amprenavir, atazanavir, darunavir, efavirenz, ritonavir, and lopinavir were found to activate hPXR, whereas abacavir, efavirenz, and nevirapine were found to activate hCAR. P-gp expression and function were significantly induced in hCMEC/D3 cells treated with these drugs at clinical concentrations in plasma. Together, our data suggest that P-gp induction could occur at the BBB during chronic treatment with antiretroviral drugs identified as ligands of hPXR and/or hCAR.
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Gary N Y
authors.initials: GN
authors.lastname: Chan
authors.forename: Rucha
authors.initials: R
authors.lastname: Patel
authors.forename: Carolyn L
authors.initials: CL
authors.lastname: Cummins
authors.forename: Reina
authors.initials: R
authors.lastname: Bendayan
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D000998:Antiviral Agents / Q000494:pharmacology*; D001921:Brain / Q000098:blood supply / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D000090702:Constitutive Androstane Receptor; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D055806:Microvessels / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D000077297:Pregnane X Receptor; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000998:Antiviral Agents; D000090702:Constitutive Androstane Receptor; D000077297:Pregnane X Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D008156:Luciferases