Gene Pathways Analysis of the Effects of Suspension Culture on Primary Human Renal Proximal Tubular Cells

Drug-induced acute kidney injury causes massive morbidity and mortality at exorbitant cost, yet there is currently no effective method for preclinical in vitro testing for nephrotoxicity. Proximal tubule cells are a key target for nephrotoxins, but heretofore, it has been a challenge to maintain their differentiation in vitro. One promising approach is to culture them in suspension, under physiological levels of shear, so as to induce and maintain structural and functional differentiation. Advances in materials, additive manufacturing, and injection molding have reduced the complexity and cost of suspension cultures hardware by orders of magnitude, making it a viable alternative for high throughput screening. This study defines the global transcriptome responses of human renal proximal tubular cells to suspension culture. GSEA/Cytoscape/ClueGO analysis showed near perfect concurrence with GPS-SIGORA analysis in the areas of mineral absorption and ribosome assembly, and defined the nucleic acid and protein mechanisms underlying the transcriptome response to suspension culture. Proximal tubular cells in suspension culture showed increased growth and viability assayed as reducing potential compared to cells cultured under static conditions. Suspension culture of human renal proximal tubular cells now allows investigations in basic cell biology, toxicology, drug screening, and tissue engineering, free of artificial matrices, feeder layers, fetal gene expression, or the need for complex engineering technologies.