Abstract

Drug-induced kidney injury (DIKI) is a major clinical problem and causes drug attrition in the pharmaceutical industry. To better predict DIKI, kidney in vitro cultures with enhanced physiological relevance are developed. To mimic the proximal tubule, the main site of adverse drug reactions in the kidney, human-derived renal proximal tubule epithelial cells (HRPTEC) were injected in one of the channels of dual channel Nortis® chips and perfused for 7 days. Tubes of HRPTEC demonstrated expression of tight junction protein 1 (ZO-1), lotus lectin and primary cilia, with localization at the apical membrane, indicating an intact proximal tubule brush border. Gene expression of cisplatin efflux transporters MATE1 (SLC47A1) and MATE2-k (SLC47A2), and Megalin endocytosis receptor (LRP2) increased 19.9{plus minus}5.0, 23.2{plus minus}8.4 and 106{plus minus}33-fold, respectively, in chip cultures compared to 2D cultures. Moreover, organic cation transporter 2 (OCT2, SLC22A2) was localized exclusively on the basolateral membrane. When infused from the basolateral compartment, cisplatin (25 µM, 72 h) induced toxicity, evident as reduced cell number and reduced barrier integrity compared to vehicle-treated chip cultures. Co-exposure with the OCT2 inhibitor cimetidine (1 mM) abolished cisplatin toxicity. In contrast, infusion of cisplatin from the apical compartment did not induce toxicity, in line with polarized localization of cisplatin uptake transport proteins, including OCT2. In conclusion, we developed a dual channel human kidney proximal tubule-on-a-chip with a polarized epithelium, restricting cisplatin sensitivity to the basolateral membrane, suggesting improved physiological relevance over single compartment models. Its implementation in drug discovery holds promise to improve future in vitro DIKI studies.

Significance Statement Human-derived kidney proximal tubule cells retained characteristics of epithelial polarization in vitro when cultured in the kidney-on-a-chip, and the dual channel construction allowed for drug exposure using the physiologically-relevant compartment. Therefore, cell polarization-dependent cisplatin toxicity could be replicated for the first time in a kidney proximal tubule-on-a-chip. The use of this physiological relevant model in drug discovery has potential to aid identification of safe novel drugs and contribute to reducing attrition rates due to drug-induced kidney injury.