Peroxiredoxin 3 Deficiency Exacerbates DSS-Induced Acute Colitis via Exosomal miR-1260b-Mediated Barrier Disruption and Proinflammatory Signaling.

Aims: Peroxiredoxin3 (Prdx3) is an intracellular antioxidant enzyme that is specifically localized in mitochondria and protects against oxidative stress by removing mitochondrial reactive oxygen species (ROS). The intestinal epithelium provides a physical and biochemical barrier that segregates host tissues from commensal bacteria to maintain intestinal homeostasis. An imbalance between the cellular antioxidant defense system and oxidative stress has been implicated in the pathogenesis of inflammatory bowel disease (IBD). However, the role of Prdx3 in the intestinal epithelium under intestinal inflammation has not been elucidated. To investigate the potential role of Prdx3 in intestinal inflammation, we used intestinal epithelial cell (IEC)-specific Prdx3-knockout mice. Results: IEC-specific Prdx3-deficient mice showed more severe colitis phenotypes with greater degrees of body weight loss, colon shortening, barrier disruption, mitochondrial damage, and ROS generation in IECs. Furthermore, exosomal miR-1260b was dramatically increased in Prdx3-knockdown colonic epithelial cells. Mechanistically, Prdx3 deficiency promoted intestinal barrier disruption and inflammation via P38-mitogen-activated protein kinase/NFκB signaling. Innovation: This is the first study to report the protective role of Prdx3 in acute colitis using IEC-specific conditional knockout mice. Conclusion: Our study sheds light on the role of exosome-loaded miRNAs, particularly miR-1260b, in IBD. Targeting miR-1260b or modulating exosome-mediated intercellular communication may hold promise as potential therapeutic strategies for managing IBD and restoring intestinal barrier integrity. Antioxid. Redox Signal. 42, 133-149.