PT  - JOURNAL ARTICLE
AU  - Kevin R. Robillard
AU  - Md. Tozammel Hoque
AU  - Reina Bendayan
TI  - Expression of ATP-Binding Cassette Membrane Transporters in Rodent and Human Sertoli Cells: Relevance to the Permeability of Antiretroviral Therapy at the Blood-Testis Barrier
AID  - 10.1124/jpet.111.186916
DP  - 2012 Jan 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 96--108
VI  - 340
IP  - 1
4099  - http://jpet.aspetjournals.org/content/340/1/96.short
4100  - http://jpet.aspetjournals.org/content/340/1/96.full
SO  - J Pharmacol Exp Ther2012 Jan 01; 340
AB  - The blood-testis barrier (BTB), composed primarily of Sertoli cells, is responsible for protecting developing germ cells from xenobiotic exposure. ATP-binding cassette (ABC) membrane-associated drug efflux transporters, P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and the multidrug resistance-associated proteins (Mrps), have been shown to restrict antiretroviral drug permeability at blood-tissue barriers such as the blood-brain barrier. However, it remains unclear whether these transporters are functional at the level of Sertoli cells and can regulate anti-HIV drug permeability at the BTB. This study investigated the functional expression of ABC transporters in a mouse Sertoli cell line system (TM4) and in primary cultures of human Sertoli cells (HSECs). Expression of multidrug resistance Mdr1a/1b/MDR1/P-gp, Mrp1/MRP1, and Mrp4/MRP4 is confirmed by quantitative polymerase chain reaction and immunoblotting analysis in TM4 cells and HSECs. Immunofluorescence studies revealed plasma membrane localization of P-gp, Mrp1/MRP1, and Mrp4/MRP4 in both cell systems. However, Bcrp expression and localization was only detected in rodent cells. Accumulation of 1) rhodamine-6G (R-6G), a fluorescent P-gp substrate, 2) [3H]atazanavir, a HIV protease inhibitor and known P-gp substrate, 3) 2′7′-bis-(2-carboxyethyl)-5-(and-6)carboxyfluorescein (BCECF), a fluorescent Mrp substrate, and 4) [3H]mitoxantrone, a BCRP substrate, by TM4 monolayer cells in the presence of established inhibitors demonstrates that these transporters are functional. In addition, several anti-HIV drugs significantly enhance the accumulation of R-6G, [3H]atazanavir, BCECF, and [3H]mitoxantrone by TM4 cells. This study provides the first evidence of ABC transporter expression and activity in Sertoli cells and suggests that these transporters could play an important role in restricting antiretroviral drug permeability at the BTB.