USP35-mediated NRF2 deubiquitination attenuates experimental cryptorchidism-induced testicular damage and H2O2-induced apoptosis and oxidative stress in spermatogonia.

Cryptorchidism, characterized by the failure of one or both testes to descend into the scrotum, is the most prevalent urogenital malformation in male infants and an important risk element of male infertility and testicular cancer. The purpose of this study was to investigate the molecular mechanisms underlying cryptorchidism-induced testicular damage, with a focus on the role of USP35. Here we established a unilateral experimental cryptorchidism model of Sprague-Dawley rats by resetting the left testis to the abdominal cavity and suturing the inguinal canal, thus preventing its natural descent. The findings indicated that apoptosis and oxidative stress (OS) levels were increased in the undescended testis (UDT) compared to the descended testis (DT) group. Subsequent mRNA sequencing of DT and UDT tissues revealed that ubiquitin specific peptidase 35 (USP35) expression was downregulated in the UDT, implying that USP35 may be an important factor in the pathogenesis of cryptorchidism. To further investigate, an oxidative damage model was constructed using H2O2-treated GC-1 spermatogonia. USP35 expression was reduced in H2O2-exposed cells, while overexpression of USP35 attenuated H2O2-induced oxidative damage by inhibiting apoptosis and OS. Mechanistically, USP35 interacted with nuclear factor erythroid 2-related factor 2 (NRF2) and stabilized its protein expression via deubiquitination. Impairment of NRF2 function abolished the protective effect of USP35 against oxidative damage in H2O2-treated GC-1 spermatogonia. Overall, these results highlight the significance of the USP35-NRF2 axis in protecting spermatogonia from oxidative injury, suggesting that USP35 may be a potential therapeutic target against cryptorchidism-induced early germ cell damage.