Functional Evaluation and Nephrotoxicity Assessment of Human Renal Proximal Tubule Cells on a Chip.

An in vitro human renal proximal tubule model that represents the proper transporter expression and pronounced epithelial polarization is necessary for the accurate prediction of nephrotoxicity. Here, we constructed a high-throughput human renal proximal tubule model based on an integrated biomimetic array chip (iBAC). Primary human renal proximal tubule epithelial cells (hRPTECs) cultured on this microfluidic platform were able to form a tighter barrier, better transporter function and more sensitive nephrotoxicity prediction than those on the static Transwell. Compared with the human immortalized HK2 model, the hRPTECs model on the chip gained improved apical-basolateral polarization, barrier function and transporter expression. Polymyxin B could induce nephrotoxicity not only from the apical of the hRPTECs, but also from the basolateral side on the iBAC. However, other chemotherapeutic agents, such as doxorubicin and sunitinib, only induced nephrotoxicity from the apical surface of the hRPTECs on the iBAC. In summary, our renal proximal tubule model on the chip exhibits improved epithelial polarization and membrane transporter activity, and can be implemented as an effective nephrotoxicity-screening toolkit.