A multi-omics study to investigate tacrolimus nephrotoxicity mechanisms

Tacrolimus, prescribed to a majority of transplanted patients is associated with nephrotoxicity, the mechanism of which remains unclear. This study aims to evaluate the impact of tacrolimus on proximal tubular cells using a multi-omics approach. LLC-PK1 cells were exposed to 5 {micro}M of tacrolimus for 24h. Intracellular proteins and metabolites, and extracellular metabolites were extracted and analysed by LC-MS/MS. The transcriptional expression of PCK-1, FBP1 and FBP2 was measured using RT-qPCR. In our cell model, tacrolimus impacted different metabolic pathways including urea cycle (e.g., citrulline, ornithine) (p < 0.0001), amino acid metabolism (e.g., valine, isoleucine, aspartic acid) (p < 0.0001) and pyrimidine metabolism (p<0.01). In addition, it induces oxidative stress (p < 0.01) shown by a decrease in total cell glutathione quantity and impacts cell energy through an increase in Krebs cycle intermediates (e.g., citrate, aconitate, fumarate) (p < 0.01) and a down-regulation of PCK-1 (p < 0.05) and FPB1 (p < 0.01), key enzymes in gluconeogenesis. Apart from glucose synthesis, gluconeogenesis is an important process in kidney mediated acid-base balance control. The observed variations found using this multi-omics approach clearly establish a dysregulation of energy production in epithelial cells of the renal tubule, and potentially of their functions, that can be implicated in tacrolimus chronic nephrotoxicity. Significance statementTacrolimus is associated with nephrotoxicity for which the mechanism remains unclear. This study shows, using multi-omics approach, that tacrolimus induces oxidative stress, and dysregulated urea cycle, amino acid metabolism, pyrimidine metabolism, krebs cycle and glucose metabolism which may impact proximal tubular cells function and can be implicated in tacrolimus chronic nephrotoxicity.