Pradeep K Karla
Howard University, USA
Title: MDR efflux transporters - New drug targets for HIV drug delivery
Biography
Biography: Pradeep K Karla
Abstract
Statement of the Problem: HIV is now considered a global pandemic affecting millions of people. Sexual transmission is the major mode of HIV infection in healthy humans. None of the vaginal microbicides and/or oral therapies has yet resulted in a complete protection from sexual transmission of HIV. Attachment of HIV to the human CD4+ T-cells, incorporation of viral enzymes and genetic material constitute the first steps of HIV sexual transmission. The purpose of the study is to screen the primary human CD4+ T-cells and transfected vaginal epithelial cells (VK2) for the presence of prominent ABCC class of drug efflux transporters: Multi Drug Resistance Associated Proteins (MRPs), Pglycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). Methodology & Theoretical Orientation: Molecular screening was performed by RT-PCR gene expression followed by sequencing analysis. Functional screening was performed by 3H-Tenofovir uptake in the presence of specific MRP inhibitor (MK571), P-gp inhibitor (Pgp-4008) and BCRP inhibitor (Fumitrimorgin-C). Intracellular radio labeled drug concentrations were analyzed by liquid scintillation counter. Findings: Single specific PCR gene products corresponding to GAPDH, MRPs1-7, MRP9, BCRP and P-gp were observed in primary human T cells. Single distinct bands for MRPs 1-9, BCRP and Pgp were observed in VK2 cells. Relative % drug uptake of tenofovir in primary human T cells in the presence of 50 μM MK571 was 173.9±5.8%), 100 μM MK571 (205.7±10.6%), 50μM Pgp4008 (215.4±9.2%) and 50 μM Fumitrimorgin (192.1±18.38%) compared to control (100±6.65%). Conclusion & Significance: The results, for the first time demonstrated the molecular and functional expression of multiple ABCC drug efflux transporters in primary human T cells and VK2 cells. Further, functional uptake studies revealed that the prominent drug efflux pumps (MRPs, Pgp and BCRP) are functionally active in unactivated human T-cells leading to decreased intracellular tenofovir concentrations.