Cisplatin binding and inactivation of mitochondrial glutamate oxaloacetate transaminase in cisplatin-induced rat nephrotoxicity.

Cisplatin is a widely used chemotherapeutic agent, but its use is limited by nephrotoxicity associated with mitochondrial dysfunction. Because its mechanisms are poorly understood, we aimed to identify the mitochondrial proteins targeted by cisplatin. We isolated renal mitochondrial proteins from Sprague-Dawley (SD) rats and performed cisplatin-affinity column chromatography. The proteins eluted were detected on SDS-PAGE and subjected to in-gel tryptic digestion and LC-MS/MS analysis. We identified glutamate oxaloacetate transaminase (GOT) and mitochondrial malate dehydrogenase (MDH). Next, we administered cisplatin intraperitoneally to SD rats to induce nephrotoxicity and assayed the activities of the enzymes. The results indicated that cisplatin caused a severe decrease in mitochondrial GOT activity on day 1 after cisplatin administration. Three d later, we also identified a decrease in mitochondrial MDH activity. Our results indicate that cisplatin binds to mitochondrial GOT and inhibits its activity, causing mitochondrial dysfunction and subsequent nephrotoxicity.