GADD45α is a direct target of TFEB and contributes to tacrolimus-induced chronic nephrotoxicity.

Tacrolimus-induced chronic nephrotoxicity (TICN) hinders long-term use of tacrolimus, but its mechanism remains unclear. Tacrolimus exerts its pharmacological effect by inhibiting calcineurin and its substrate nuclear factor of activated T cells. Whether the inhibition of other calcineurin substrates is related to TICN remains to be explored. Transcription factor EB (TFEB), a substrate of calcineurin, plays a crucial role in homeostasis. Herein, we found that tacrolimus inhibited TFEB nuclear translocation and activity in mouse kidneys and HK-2 cells. Then, TFEB gain and loss of function rescued and exacerbated, respectively, the effect of tacrolimus in HK-2 cells. Furthermore, TFEB activation by both phosphorylation site mutation and agonist rescued TICN in mice. To elucidate the mechanism of TFEB, we analyzed ChIP-Seq data. We identified growth arrest and DNA damage-inducible 45α (GADD45α) as a transcriptional target of TFEB via ChIP and dual-luciferase reporter assays. Then we revealed that GADD45α overexpression rescued DNA damage and kidney injury caused by tacrolimus or TFEB knockdown in vitro and vice versa. The protective effect of GADD45α against TICN and DNA damage was further demonstrated by overexpressing it in mice. In conclusion, the persistent inhibition of the TFEB/GADD45α pathway by tacrolimus contributes to TICN. This study identifies a specific target for intervention in TICN.