Comparing predictive drug nephrotoxicity biomarkers in kidney 3-D primary organoid culture and immortalized cell lines

The cellular microenvironment is recognized to play a key role in stabilizing cell differentiation states and phenotypes in culture. This study addresses the hypothesis that preservation of in vivo-like tissue architecture in vitro produces a cell culture more capable of responding to environmental stimuli with clinically relevant toxicity biomarkers. This was achieved using kidney proximal tubules in three-dimensional organoid hydrogel culture, with comparisons to conventional monolayer kidney cell cultures on plastic. Kidney proximal tubule cultures and two immortalized kidney cell line monolayer cultures exposed to known nephrotoxic drugs were evaluated for inflammatory cytokines, nephrotoxicity-associated genes, Kim-1 protein, cytochrome enzymes, and characteristic cellular enzyme shedding. Significant similarities are shown for these traditional biomarkers of kidney toxicity between in vivo and 3-D organoid endpoints of drug toxicity, and significantly, a consistent lack of clinically relevant endpoints produced by traditional 2-D kidney cell cultures. These findings impact both in vitro bioreactor-based kidney functional and regenerative medicine models, as well as high-throughput cell-based drug screening validations.