Abstract
Objective: Clostridioides difficile infection (CDI) has been primarily associated with the toxin B (TcdB), which can activate the intestinal immune system and lead to pathological damage. Even though the biological functions of intestine epithelial cell-derived extracellular vesicles (I-Evs) have been well documented, the role of I-Evs in the process of CDI is still unknown. Methods: I-Evs were isolated from mouse intestine tissues by ultracentrifugation protocol, identified by electron microscopy, nanoparticle tracking, sucrose density gradient centrifugation, and western blotting. Intestinal pathological damage was measured after intraperitoneal injection of TcdB into mice. Results: We isolated I-Evs ranging from 100–200 nm in mean diameter, with a density of 1.09-1.17 g/mL. These I-Evs expressed the extracellular vesicle-associated specific surface markers, CD63 and TSG101. In vitro, 50 µg I-Evs decreased the expression of IL-6, TNF-a, IL-1β, and IL-22 induced by 0.8 ng/mL C. difficile TcdB, and increased expression of TGF-b1. In vivo, I-Evs also promoted regulatory T cell induction, which improved the survival rate of mice up to 80% relative to C. difficile TcdB mice, dependent on the TGF-b1 signalling pathway. Conclusion: As an emerging immunotherapy, I-Evs can reduce the intraperitoneal infection induced by C. difficile TcdB and improve survival in mice.