Pectolinarigenin mitigates 5-FU-induced intestinal mucositis via suppressing ferroptosis through activating PPARgamma/GPX4 signaling.

BACKGROUND: 5-Fluorouracil (5-FU), one of the mostly commonly used chemotherapeutic agents, frequently induces intestinal mucositis, severely impacting patient quality of life and limiting treatment efficacy. Pectolinarigenin (PEC), a bioactive compound isolated from Chinese medicinal herb Dajitan, exhibits anti-inflammatory, antioxidative, and anticancer properties. However, its protective effect on 5-FU-induced mucositis and the underlying molecular mechanisms remains unclear. PURPOSES: To investigate the therapeutic effects and underlying mechanisms of PEC in 5-FU-induced intestinal mucositis. METHODS: Mouse models of ileal and colonic injury were used to study 5-FU-induced mucositis. Histological and biochemical assays assessed mucositis severity. A panel of 71 antioxidants was screened for their ability to inhibit 5-FU-induced cells death. Transcriptome sequencing, molecular docking, molecular dynamics simulations, and Western blotting explored PEC's mechanism of action, with a focus on its role in activating the PPARgamma signaling pathway. Meanwhile, 5-aminosalicylic acid (5-ASA, the first-line therapeutic agent for treating ulcerative colitis) and pioglitazone (a known PPARgamma agonist) were used as positive controls. RESULTS: 5-FU induced ferroptosis and intestinal inflammation both in vivo and in vitro, characterized by increased iron and ROS accumulation, reduced GSH levels, and elevated lipid peroxidation biomarkers. Histological analysis showed severe intestinal mucosal damage. Among all tested phytochemicals, PEC demonstrated the best ameliorative effects on 5-FU-induced mucositis, showing impressive therapeutic efficacy in both cellular and animal models. PEC significantly mitigated 5-FU induced mucositis via reducing iron accumulation, lowering ROS and MDA levels, restoring GSH, and normalizing ferroptosis-related markers. Transcriptomic analysis combined cellular assays revealed that the PPARgamma signaling plays a critical role in the protective effects of PEC against 5-FU-induced intestinal cellular injury. Further investigations showed that PEC could activate the PPARgamma/GPX4 signaling pathway both in vitro and in vivo, which in turn, restored tight junction integrity and suppressed intestinal ferroptosis, ultimately providing protective effects against 5-FU-induced intestinal injury. CONCLUSIONS: This study uncovers a previously unrecognized ferroptosis-related mechanism underlying 5-FU-induced intestinal mucositis, while PEC significantly mitigates 5-FU-induced intestinal mucositis by activating the PPARgamma/GPX4 axis. Our findings suggest that activating the PPARgamma/GPX4 signaling pathway using phytochemicals represents a promising therapeutic strategy for mitigating chemotherapy-induced intestinal mucositis.