Phillygenin, a Plant-Derived Lignan, Attenuates Renal Inflammation, Fibrosis, and Pyroptosis in a Unilateral Ureteral Obstruction Model

Background/Objectives: Phillygenin (PHI), a natural lignan derived from Forsythia suspensa, has garnered attention for its potential to alleviate chronic diseases, including chronic colitis, pulmonary fibrosis, and diabetes. Chronic kidney disease (CKD) poses a global health challenge, characterized by high morbidity and mortality rates and associated with a spectrum of secondary complications. In this study, we aim to investigate the therapeutic effectiveness of PHI on CKD and also identify molecular signals by using a unilateral ureteral obstruction (UUO) mouse model and in vitro experiments. Methods: C57BL/6 mice were administered PHI at 50 mg/kg/day to assess its therapeutic effectiveness. In vitro, lipopolysaccharide (LPS) and adenosine triphosphate (ATP) were used to induce pyroptosis, also known as pyroptosis, in renal proximal tubular cells (NRK52E). Results: After PHI treatment for 14 consecutive days, the collagen deposition and extracellular matrix (ECM) accumulation, the expression of oxidative stress response proteins (catalase, superoxide dismutase 2, NADPH oxidase 4, and thioredoxin reductase 1), pro-inflammatory markers (TNF-α and Cyclooxygenase-2(COX-2), and infiltration of neutrophils and macrophages were significantly ameliorated in the UUO mice. Interestingly, the pyroptosis-related proteins (NLRP3/Caspase-1/GSDMD/IL-1β) and cell apoptotic death were also conspicuously relieved after treatment with PHI. Furthermore, PHI administration significantly attenuated the ATP/LPS-induced NF-κB/NLRP3/Caspase-1/GSDMD pyroptosis signal pathway in NRK52E cells. Conclusions: These results demonstrate, for the first time, that PHI treatment ameliorates inflammation and the related pyroptosis via inhibitory regulation of the NF-κB/NLRP3/Caspase-1/GSDMD axis, leading to attenuated renal fibrosis and progressive CKD in UUO mice and in vitro. Our findings suggest that PHI could be a nutraceutical candidate for attenuating CKD progression.