title: P-glycoprotein (ABCB1) activity decreases raltegravir disposition in primary CD4+P-gphigh cells and correlates with HIV-1 viral load.
abstract: To evaluate the role of P-glycoprotein (P-gp) and multidrug-resistant-protein 1 (MRP1) on raltegravir intracellular drug disposition in CD4+ T cells, investigate the effect of HIV-1 infection on P-gp expression and correlate HIV-1 viraemia with P-gp activity in primary CD4+ T cell subsets.
  
  
  
  The cellular accumulation ratio of [(3)H]raltegravir was quantified in CD4+ T cell lines overexpressing either P-gp (CEM-P-gp) or MRP1 (CEM-MRP1) and in primary CD3+CD4+ T cells with high (P-gp(high)) and low P-gp activity (P-gp(low)); inhibition of efflux transporters was confirmed by the intracellular retention of calcein-AM. The correlation of P-gp activity with HIV-1 viraemia was assessed in naive and memory T cell subsets from 21 HIV-1-infected treatment-naive subjects.
  
  
  
  [(3)H]Raltegravir cellular accumulation ratio decreased in CEM-P-gp cells (P < 0.0001). XR9051 (a P-gp inhibitor) and HIV-1 PIs reversed this phenomenon. Primary CD4+P-gp(high) cells accumulated less raltegravir (38.4% ± 9.6%) than P-gp(low) cells, whereas XR9051 also reversed this effect. In vitro HIV-1 infection of PBMCs and stimulation of CD4+ T cells increased P-gp mRNA and P-gp activity, respectively, while primary CD4+P-gp(high) T cells sustained a higher HIV-1 replication than P-gp(low) cells. A significant correlation between HIV-1 viraemia and P-gp activity was found in different CD4+ T cell subsets, particularly memory CD4+ T cells (r = 0.792, P < 0.0001).
  
  
  
  Raltegravir is a substrate of P-gp in CD4+ T cells. Primary CD4+P-gp(high) T cells eliminate intracellular raltegravir more readily than P-gp(low) cells and HIV-1 viraemia correlates with P-gp overall activity. Specific CD4+P-gp(high) T cell subsets could facilitate the persistence of viral replication in vivo and ultimately promote the appearance of drug resistance.
authors.affiliation: AIDS Research Institute IrsiCaixa, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Gerard
authors.initials: G
authors.lastname: Minuesa
authors.affiliation: Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine (IBUB), University of Barcelona, 08028 Barcelona, Spain Oncology Program, National Biomedical Research Institute on Liver and Gastrointestinal Diseases (CIBER EHD), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Arimany-Nardi
authors.affiliation: AIDS Research Institute IrsiCaixa, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Itziar
authors.initials: I
authors.lastname: Erkizia
authors.affiliation: AIDS Research Institute IrsiCaixa, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Samandhy
authors.initials: S
authors.lastname: Cedeño
authors.affiliation: Fundació Lluita contra la Sida, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Moltó
authors.affiliation: AIDS Research Institute IrsiCaixa, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain Fundació Lluita contra la Sida, Hospital Universitari Germans Trias i Pujol, Badalona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
authors.forename: Bonaventura
authors.initials: B
authors.lastname: Clotet
authors.affiliation: Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine (IBUB), University of Barcelona, 08028 Barcelona, Spain Oncology Program, National Biomedical Research Institute on Liver and Gastrointestinal Diseases (CIBER EHD), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Marçal
authors.initials: M
authors.lastname: Pastor-Anglada
authors.affiliation: AIDS Research Institute IrsiCaixa, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain Universitat de Vic, Universitat Central de Catalunya (UVic-UCC), Vic, Spain jmpicado@irsicaixa.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Martinez-Picado
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics / Q000378:metabolism; D019380:Anti-HIV Agents / Q000378:metabolism*; D001597:Benzylidene Compounds / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000821:virology; D002460:Cell Line; D002478:Cells, Cultured; D005452:Fluoresceins / Q000378:metabolism; D015658:HIV Infections / Q000821:virology; D015497:HIV-1 / Q000187:drug effects / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D007156:Immunologic Memory; D000068898:Raltegravir Potassium / Q000378:metabolism*; D019438:Ritonavir; D044005:Tetrahydroisoquinolines / Q000494:pharmacology; D019562:Viral Load / Q000187:drug effects*; D014766:Viremia / Q000188:drug therapy; D014779:Virus Replication / Q000187:drug effects
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D019380:Anti-HIV Agents; D001597:Benzylidene Compounds; D005452:Fluoresceins; D044005:Tetrahydroisoquinolines; C118656:XR 9051; C085925:calcein AM; D000068898:Raltegravir Potassium; D019438:Ritonavir