Drug transporter expression and function in primary cultures of human renal epithelial cells

Abstract

Primary epithelial cell cultures are an important model for studying drug transporters in vitro. They can be used as a replacement for animal models and possibly are more suitable due to variation in transporter expression between animal and human tissue. The aim of this study was to validate the use of primary epithelial cell cultures as a model for studying drug transporter expression and function in human kidney.Primary epithelial cells were isolated from human kidney tissue samples and cultured for 7 to 10 days. qPCR was used to determine mRNA expression of key transporters in the primary cells. Cells were grown on permeable filter supports to create polarised monolayers and transport of a range of radio‐labelled compounds was tested across the cell monolayers. Dye retention assays were used to determine the presence of functional efflux transporters.Expression of mRNA for a range of prototypic transporters including OCT‐2, MDR1 and MRP was confirmed. Basolateral to apical transport of various compounds including metformin and indomethacin was shown suggesting possible elimination via the kidney. Hoechst 33342 retention assay showed expression of functional MDR1. CMFDA dye retention assay showed presence of MK571 sensitive transporters, likely to be MRPs. These findings show that primary cell cultures are a good model for studying drug transporter expression and function in human kidney.