Crotoxin Modulates Epithelial–Immune Crosstalk to Restrain Intestinal Inflammation

Introduction: Intestinal epithelial barrier integrity is essential for maintaining host–microbiota homeostasis by limiting microbial translocation and orchestrating mucosal immune responses. Its disruption is increasingly recognized as a key driver of inflammatory bowel diseases, promoting immune activation and tissue damage. Crotoxin (CTX), the major component of Crotalus durissus terrificus venom, exhibits immunomodulatory properties, yet its effects on epithelial–immune interactions and intestinal inflammation remain unknown. Objectives: Investigate the effects of CTX during the early phase of acute intestinal inflammation, focusing on epithelial–immune responses, disease progression, and gut microbiota. Methods and Results: In in vitro experiments, Caco-2 cells were stimulated with IFN-γ in the presence or absence of CTX for 18 h. CTX attenuated IFN-γ-induced epithelial dysfunction by preserving epithelial barrier integrity and the expression of the tight junction protein ZO-1, while reducing ICAM-1 expression and IL-8 secretion. Supernatants from IFN-γ-stimulated Caco-2 cells induced neutrophil and monocyte migration in a transwell assay, whereas this response was reduced using supernatants from CTX-treated cultures. In vivo experiments, acute colitis was induced in mice by intrarectal TNBS instillation, followed 12 h later by intraperitoneal CTX administration. CTX reduced body weight loss, clinical scores, and recruitment of neutrophils, monocytes, and macrophages to the lamina propria. CTX also partially reversed TNBS-induced gut dysbiosis. Notably, FPR blockade with Boc2 abolished CTX-mediated protection. Conclusion: CTX attenuates early inflammatory events in acute colitis by preserving epithelial barrier integrity, limiting leukocyte recruitment, and partially restoring gut microbiota homeostasis. These effects involve FPR signaling, supporting a role for FPRs in CTX-mediated regulation of epithelial–immune interactions during intestinal inflammation.