Gene networking in colistin-induced nephrotoxicity reveals an adverse outcome pathway triggered by proteotoxic stress

Colistin has been widely used for the treatment of infections of multidrug-resistant Gram-negative bacteria, despite the fact that it induces serious kidney injury as a side effect. To investigate the mechanism underlying its nephrotoxicity, colistin methanesulfonate sodium (CMS; 25 or 50 mg/kg) was administered via intraperitoneal injection to Sprague-Dawley rats daily over 7 days. Serum biochemistry and histopathology indicated that nephrotoxicity occurred in the rats administered with CMS. Whole-genome microarrays indicated 894 differentially expressed genes in the group treated with CMS (analysis of variance, false discovery rate <0.05, fold-change ≥1.3). Gene pathway and networking analyses revealed that genes associated with proteotoxic stress, including ribosome synthesis, protein translation, and protein folding, were significantly associated with the nephrotoxicity induced by CMS. It was found that colistin inhibited the expression of the target genes heat shock factor 1 and nuclear factor erythroid-2-related factor-2, which are associated with proteostasis, and that nephrotoxicity of CMS may be initiated by proteotoxic stress due to heat shock response inhibition, leading to oxidative stress, endoplasmic reticulum stress, cell cycle arrest and apoptosis, eventually leading to cell death. A putative adverse outcome pathway was constructed based on the integrated gene networking data, which may clarify the mode of action of colistin-induced nephrotoxicity.