Stress-responsive gene TauT and acute kidney injury

BACKGROUND: Cisplatin is a commonly used chemotherapeutic agent that has a major limitation because of its nephrotoxicity. We have demonstrated that cisplatin down-regulates the expression of the taurine transporter gene (TauT) in renal cells and that forced overexpression of TauT protects against cisplatin-induced apoptosis in renal cells in vitro and in vivo. In the present study, we have investigated how TauT is regulated by p53 and c-Jun and its role during acute kidney injury (AKI). METHODS: Regulation of TauT by p53 and c-Jun was determined by reporter gene assay, DNA binding, Western blot analysis, and immunohistochemistry. RESULTS: TauT was down-regulated by p53 and up-regulated by c-Jun. Two potential binding sites for c-Jun were identified in the promoter region of TauT. Inhibition of c-Jun N-terminal kinase (JNK) enhanced TauT promoter activity. Overexpression of TauT protects against cisplatin-induced kidney injury in a TauT transgenic mouse model. CONCLUSIONS: Our findings suggest that TauT plays a critical role in renal function. Expression of TauT is negatively regulated by p53 and positively regulated by c-Jun, which is mediated by the JNK signaling pathway. The outcome level of TauT may determine the fate of renal cells during stress-induced AKI.