Perfluorooctane sulfonates drives colitis via a gut microbiota-bile acid-endoplasmic reticulum stress axis in mice: Mechanistic validation and targeted interventions.

Perfluorooctane sulfonate (PFOS), a widespread environmental pollutant, is implicated in systemic toxicity, yet its role in colitis remains unclear. This study aimed to investigate whether PFOS exacerbates colitis via the gut microbiota-bile acid-endoplasmic reticulum stress (ERS) axis and to explore potential interventions. Following 15-week oral PFOS exposure (0.1 or 0.3 mg/kg/d), mice developed dose-dependent colitis, featuring weight loss, colon shortening, barrier dysfunction, and elevated inflammation. High-dose PFOS disturbed bile acid homeostasis, depleting conjugated species like tauroursodeoxycholic acid (TUDCA) while accumulating deconjugated bile acids such as deoxycholic acid (DCA), thereby activating ERS pathways (PERK/eIF2α, IRE1/XBP1, ATF6). Gut microbiota analysis revealed reduced diversity, a lower Firmicutes/Bacteroidetes ratio, increased bacteria with bile salt hydrolase (BSH) activity (e.g., Lachnospira), and decreased potential bacteria (e.g., Akkermansia). Interventions with TUDCA, a BSH inhibitor, or fecal microbiota transplantation from healthy donors alleviated colitis, restored conjugated bile acids, and suppressed ERS. These findings demonstrate that PFOS triggers colitis via BSH-mediated bile acid deconjugation and ERS activation, highlighting the therapeutic potential of targeting this axis.