Daphnetin Alleviates Sepsis-Associated Acute Kidney Injury by Promoting Autophagy and Suppressing Non-canonical NF-κB Signaling.

BACKGROUND: Sepsis-Associated Acute Kidney Injury (SA-AKI) is a lifethreatening complication with high mortality and limited treatment options. Daphnetin (DAP), a coumarin derivative with anti-inflammatory activity, has shown promise in several inflammatory disorders, but its role in SA-AKI remains unclear. METHODS: We induced SA-AKI in mice using the Cecal Ligation and Puncture (CLP) model and established an in vitro injury model by stimulating HK-2 cells with Lipopolysaccharide (LPS). The effects of DAP were evaluated in both models. RNA sequencing was performed to identify the mechanisms underlying DAP-mediated protective effects, and the results were further validated by immunoblotting and related assays. RESULTS: DAP treatment markedly reduced renal injury, lowered serum creatinine and blood urea nitrogen levels, preserved renal histological architecture, and attenuated tubular cell apoptosis. It also reduced the production of pro-inflammatory cytokines and enhanced autophagic activity. Transcriptomic analysis together with biochemical validation implicated non-canonical nuclear factor kappa-B (NF-κB) signaling as a potential mediator of the anti-inflammatory effects of DAP. In addition, DAP reduced pro-inflammatory M1 macrophage infiltration in the kidney. DISCUSSION: These findings expand current understanding of the mechanisms underlying DAP-mediated renoprotection by demonstrating enhanced autophagic activity in experimental SA-AKI. The observation that pharmacological inhibition of NF-κB-inducing kinase (NIK) also enhances autophagic activity suggests that suppression of non-canonical NF-κB signaling contributes to autophagy regulation. Together with its anti-inflammatory effects, these findings support a multifaceted mechanism underlying the renoprotective actions of DAP. CONCLUSION: DAP attenuates inflammation and kidney injury in SA-AKI, accompanied by inhibition of non-canonical NF-κB signaling and enhanced autophagic activity. These findings suggest that DAP may represent a promising therapeutic candidate for SAAKI.