Specific increase in MDR1 mediated drug-efflux in human brain endothelial cells following co-exposure to HIV-1 and saquinavir

• Published in: PloS one Vol. 8; no. 10; p. e75374
• Main Authors: Roy, Upal, Bulot, Christine, Honer zu Bentrup, Kerstin, Mondal, Debasis
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 03-10-2013; Public Library of Science (PLoS)
• Subjects: Acquired immune deficiency syndrome; AIDS; Anti-HIV Agents - metabolism; Anti-HIV Agents - pharmacology; Antiretroviral drugs; Antiviral agents; ATP Binding Cassette Transporter, Subfamily B, Member 1 - antagonists & inhibitors; ATP Binding Cassette Transporter, Subfamily B, Member 1 - deficiency; ATP Binding Cassette Transporter, Subfamily B, Member 1 - genetics; ATP Binding Cassette Transporter, Subfamily B, Member 1 - metabolism; Biological Transport; Blood-brain barrier; Blood-Brain Barrier - cytology; Blood-Brain Barrier - drug effects; Blood-Brain Barrier - metabolism; Blood-Brain Barrier - virology; Brain; Calcein; Central nervous system; Cytokines; Drug delivery; Drug delivery systems; Drug therapy; Drugs; Efflux; Endothelial cells; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Endothelial Cells - virology; Endothelium; Experiments; Exposure; Gene expression; Gene Expression Regulation - drug effects; Gene Silencing; Glycoproteins; Health aspects; Health sciences; Highly active antiretroviral therapy; HIV; HIV-1 - drug effects; HIV-1 - physiology; Human immunodeficiency virus; Humans; Immunology; Infections; Inflammation; Kinases; Low level; Material requirements planning; MDR1 protein; Microvasculature; MRP1 protein; Multidrug Resistance-Associated Proteins - metabolism; P-Glycoprotein; Permeability; Pharmacology; Protease inhibitors; Proteases; Proteinase inhibitors; Proteins; Reservoirs; RNA, Small Interfering - genetics; Saquinavir; Saquinavir - metabolism; Saquinavir - pharmacology; siRNA; Substrates; Viruses; Louisiana; Florida; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0075374

Persistence of HIV-1 reservoirs within the Central Nervous System (CNS) remains a significant challenge to the efficacy of potent anti-HIV-1 drugs. The primary human Brain Microvascular Endothelial Cells (HBMVEC) constitutes the Blood Brain Barrier (BBB) which interferes with anti-HIV drug delivery into the CNS. The ATP binding cassette (ABC) transporters expressed on HBMVEC can efflux HIV-1 protease inhibitors (HPI), enabling the persistence of HIV-1 in CNS. Constitutive low level expression of several ABC-transporters, such as MDR1 (a.k.a. P-gp) and MRPs are documented in HBMVEC. Although it is recognized that inflammatory cytokines and exposure to xenobiotic drug substrates (e.g HPI) can augment the expression of these transporters, it is not known whether concomitant exposure to virus and anti-retroviral drugs can increase drug-efflux functions in HBMVEC. Our in vitro studies showed that exposure of HBMVEC to HIV-1 significantly up-regulates both MDR1 gene expression and protein levels; however, no significant increases in either MRP-1 or MRP-2 were observed. Furthermore, calcein-AM dye-efflux assays using HBMVEC showed that, compared to virus exposure alone, the MDR1 mediated drug-efflux function was significantly induced following concomitant exposure to both HIV-1 and saquinavir (SQV). This increase in MDR1 mediated drug-efflux was further substantiated via increased intracellular retention of radiolabeled [(3)H-] SQV. The crucial role of MDR1 in (3)H-SQV efflux from HBMVEC was further confirmed by using both a MDR1 specific blocker (PSC-833) and MDR1 specific siRNAs. Therefore, MDR1 specific drug-efflux function increases in HBMVEC following co-exposure to HIV-1 and SQV which can reduce the penetration of HPIs into the infected brain reservoirs of HIV-1. A targeted suppression of MDR1 in the BBB may thus provide a novel strategy to suppress residual viral replication in the CNS, by augmenting the therapeutic efficacy of HAART drugs.