Gomisin D alleviates podocyte injury in diabetic kidney disease by inhibiting oxidative stress via activation of the GSK3β (Ser9)/Nrf2/ARE signaling pathway

Objective: To explore whether gomisin D, a lignan derived from Schisandra chinensis, protects against podocyte injury in diabetic kidney disease and to elucidate its underlying mechanisms. Methods: Network pharmacology was employed to analyze the potential interactions between gomisin D and podocyte injury- related targets in diabetic nephropathy. A high glucose-induced injury model of mouse podocyte MPC5 cells was established, and the effect of gomisin D on podocyte injury was subsequently evaluated by measurement of reactive oxygen species levels and biochemical markers and Western blotting. Molecular docking and further molecular biology assays were conducted to explore the interaction between gomisin D and the target protein. Results: Gomisin D inhibited high glucose-induced oxidative stress, improved cell viability, and preserved the expression of podocin and synaptopodin. Network pharmacology identified glycogen synthase kinase-3β (GSK3β) as a key target. Molecular docking predicted a potential interaction between gomisin D and GSK3β, which was further validated by drug affinity responsive target stability and cellular thermal shift assay, confirming direct binding in live cells. Mechanistically, gomisin D enhanced the phosphorylation of GSK3β at Ser9, promoted the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2), and upregulated levels of downstream antioxidant proteins heme oxygenase-1 and NAD(P) H quinone oxidoreductase 1. Furthermore, forced expression of the constitutively active GSK3β mutant S9A decreased GSK3β (Ser9) phosphorylation and reversed gomisin D-induced upregulation of these antioxidant markers. Conclusions: Gomisin D mitigates high glucose-induced podocyte injury in vitro by inhibiting oxidative stress via activation of the GSK3β(Ser9)/Nrf2/ARE signaling pathway.