A multi-omics study to investigate tacrolimus nephrotoxicity mechanisms

Abstract

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 μM 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.