TRAF1 improves cisplatin-induced acute kidney injury via inhibition of inflammation and metabolic disorders

Cisplatin-induced acute kidney injury (AKI) is a severe clinical complication with no satisfactory therapies in the clinic. Tumor necrosis factor receptor (TNFR)-associated factor 1 (TRAF1) plays a vital role in both inflammation and metabolism. However, the TRAF1 effect in cisplatin induced AKI needs to be evaluated. We observed the role of TRAF1 in eight-week-old male mice and mouse proximal tubular cells both treated with cisplatin by examining the indicators associated with kidney injury, apoptosis, inflammation, and metabolism. TRAF1 expression was decreased in cisplatin-treated mice and mouse proximal tubular cells (mPTCs), suggesting a potential role of TRAF1 in cisplatin-associated kidney injury. TRAF1 overexpression significantly alleviated cisplatin-triggered AKI and renal tubular injury, as demonstrated by reduced serum creatinine (Scr) and urea nitrogen (BUN) levels, as well as the ameliorated histological damage and inhibited upregulation of NGAL and KIM-1. Moreover, the NF-κB activation and inflammatory cytokine production enhanced by cisplatin were significantly blunted by TRAF1. Meanwhile, the increased number of apoptotic cells and enhanced expression of BAX and cleaved Caspase-3 were markedly decreased by TRAF1 overexpression both in vivo and vitro. Additionally, a significant correction of the metabolic disturbance, including perturbations in energy generation and lipid and amino acid metabolism, was observed in the cisplatin-treated mice kidneys. TRAF1 overexpression obviously attenuated cisplatin-induced nephrotoxicity, possibly by correcting the impaired metabolism, inhibiting inflammation, and blocking apoptosis in renal tubular cells. These observations emphasize the novel mechanisms associated to metabolism and inflammation of TRAF1 in cisplatin-induced kidney injury.