SENP2 participates in DBP-induced oxidative stress injury via mediating Nrf2 de-SUMOylation

Exposure to Di-n-butyl phthalate (DBP) is associated with congenital and acquired defects in the male reproductive system, and DBP-induced oxidative stress plays a critical role in this process. The activation of the Nrf2 antioxidant pathway plays a protective role and its ubiquitin-dependent degradation is well-established. However, the role of Nrf2 SUMOylation remains unclear. This study investigated whether the de-SUMOylating enzyme SENP2 regulates the Nrf2 pathway and mediates DBP-induced damage in Leydig cells. In both DBP-exposed rat testes and TM3 cells, SENP2 expression was significantly downregulated. Molecular assays, including Ni²⁺-NTA pull-down and co-immunoprecipitation (co-IP), confirmed that Nrf2 is modified by SUMO2/3 at lysine 533 and that SENP2 mediates its de-SUMOylation. Gain- and loss-of-function assays in TM3 cells showed that SENP2 knockdown activated the Nrf2 pathway, facilitated Nrf2 nuclear translocation, upregulated downstream antioxidant proteins, lowered intracellular ROS levels, and partially rescued DBP-impaired testosterone secretion. Conversely, SENP2 overexpression suppressed Nrf2 activity and nuclear translocation, and exacerbated oxidative damage and secretory dysfunction. These findings indicate that SENP2 participates in DBP-induced Leydig cell oxidative injury by modulating the de-SUMOylation of Nrf2. This study provides novel insights into the post-translational regulation of Nrf2 in environmental toxicant-induced reproductive injury, identifying the SENP2/Nrf2 axis as a potential target for intervention.