Effect of endoplasmic reticulum stress preconditioning on cytotoxicity of clinically relevant nephrotoxins in renal cell lines

The cytoprotection of LLC-PK1 cells afforded by endoplasmic reticulum (ER) stress preconditioning suggests that the ER plays an important role during drug-induced renal toxicity. However, in vitro studies have been largely limited to LLC-PK1 cells and model toxins. Therefore, we tested the hypothesis that cytoprotection following ER stress preconditioning is a common property of renal cell lines (LLC-PK1 (pig), NRK-52E (rat), HEK293 (human), MDCK (dog)) and extends to clinically relevant nephrotoxins. ER stress inducers (tunicamycin, thapsigargin and oxidized dithiothreitol (DTTox)) resulted in a dose-dependent increase in GRP78 and GRP94 stress protein expression, but the magnitude of induction was cell line- and inducer-dependent. Toxicity of the model toxins iodoacetamide and tert-butylhydroperoxide was modified by preconditioning. DTTox was effective in decreasing the toxicity in all cell lines, but protection was variable with tunicamycin and thapsigargin. Toxicity of clinically relevant drugs (cisplatin, gentamicin, glyoxylate, cyclosporine A, p-aminophenol) was significantly decreased in cells preconditioned by tunicamycin or DTTox. These results demonstrate that ER stress preconditioning offers cytoprotection against clinically relevant nephrotoxins in renal cell lines from multiple species, although there were qualitative and quantitative differences between the cell lines. These results support the hypothesis that ER is involved in drug-induced renal toxicity.