DEF6 regulates renal ischemia reperfusion injury through suppressing the WWP2 mediated ubiquitination of PARP1

Background: Renal ischemia-reperfusion injury (RIRI) stands as an unavoidable complication arising from kidney surgery, profoundly intertwined with its prognosis. The role of differentially expressed in FDCP 6 homolog (DEF6) in RIRI remains elusive, despite its confirmation as a potential therapeutic target for diverse diseases. Here, we investigated the mechanism by which DEF6 regulated RIRI. Methods: RNA sequencing data and IP-MS were used to identify the expression and potential targets of DEF6 through bioinformatics analysis. To elucidate the impact of DEF6 on RIRI, both an in vivo model of RIRI in mice and an in vitro model of kidney cell hypoxia/reoxygenation were established. Biochemical and histological analyses were used to investigate the influence of DEF6 on kidney damage mediated by RIRI. Results: We confirmed that DEF6 was upregulated during RIRI and had a close correlation with RIRI-related inflammation and apoptosis. Moreover, inhibition of DEF6 could mitigate RIRI-induced kidney damage, inflammation, and apoptosis. Through our comprehensive mechanistic investigation, we revealed that DEF6 interacts with poly ADP-ribose polymerase 1 (PARP1) and suppresses the ubiquitination of PARP1. Inhibition of DEF6 resulted in reduced cleaveage of PARP1, leading to a marked suppression of PARP1-mediated apoptosis activation. The aggravation effect on inflammation and apoptosis achieved through DEF6 was nullified by the inhibition of NF-κB and Bax/Bcl2 signaling activation through PARP1 deletion. Conclusions: The findings from our study indicate that DEF6 suppressed the WWP2 mediated ubiquitination of PARP1 and modulates the activation of NF-κB and Bax/Bcl2 pathway, thus involved in RIRI-induced inflammation and apoptosis. These results suggest that DEF6 holds promise as a potential therapeutic target for mitigating RIRI.