High-Throughput Microfluidic Platform for Culture of 3D-Kidney Tissue Models

Drug toxicity remains a major issue in drug discovery and stresses the need for better predictive models. Here, we describe the development of a perfused renal proximal tubule cell (RPTC) model in Mimetas’ OrganoPlates® to predict kidney toxicity. The OrganoPlate® is a microfluidic platform, which enables high-throughput culture of boundary tissues in miniaturized organ models. In OrganoPlates®, ECM gels can be freely patterned in microchambers through the use of PhaseGuide technology. PhaseGuides define channels within microchambers that can be used for ECM deposition or medium perfusion. The microfluidic channel dimensions not only allow solid tissue and barrier formation, but also perfused tubular epithelial vessel structures can be grown. The goal of developing a perfused RPTC model is to reconstruct viable and leak-tight boundaries for performing cytotoxicity, as well as transport and efficacy studies. Human RPTC (SA7K clone, Sigma) were grown against an ECM in a 3channel OrganoPlate®, yielding access to both the apical and basal side. Confocal imaging revealed that the cells formed a tubular structure. Staining showed tight junction formations (ZO-1), cilia pointing into the lumen (acetylated tubulin) and correct polarization with microvilli on the apical side of the tubule (ezrin). Tightness of the boundary over several days was shown by diffusion of a dextran dye added to the lumen of the tubule. Addition of toxic compounds resulted in disruption of the barrier which could be monitored in time. The time point of loss of integrity corresponds with the concentration and the toxic effect of the compound. Furthermore, fluorescent transport assays showed functional transport activity of in- and efflux transporters. The 3D proximal tubules cultured in the OrganoPlate® are suitable for high-throughput toxicity screening, trans-epithelial transport studies, and complex co-culture models to recreate an in vivo-like microenvironment.