PhD Student Jeju National University Jeju, Republic of Korea
Abstract: Cholera, caused by Vibrio cholerae, leads to severe diarrhea due to cholera toxin (CT), which disrupts intestinal barrier function. While CT’s mechanisms are primarily associated with ion secretion, an effective late-stage therapy is urgently needed. The impact of CT on intestinal stem cells (ISCs) and their niche remains poorly understood. In this study, we use adult stem cells-derived intestinal organoids to investigate how CT affects not only ISC niche but also BMI1+ cells, a subset of quiescent intestinal stem cells, over 72 hours. Our results show a significant initial increase in BMI1 expression, followed by a substantial decline, suggesting a potential rescue effect ultimately followed by stem cell exhaustion. Additionally, lysozyme production remains consistently reduced, indicating impaired local antimicrobial response. CT exposure alters ISC markers (such as LGR5 and SOX9) at gene and protein levels, reduces stem cell proliferation, and disrupts tight junctions, leading to compromised intestinal barrier integrity. We also observe a mislocalization and mismatch of tight junction proteins, including claudin-2, β-catenin and zonulin-1, resulting in organoid shrinkage and opening. Based on these findings, we propose a dual-mechanism therapy combining calcium channel inhibitors and zonulin-1 modulators, dissolved in the organoid medium. This combination aims to prevent the cystic phenotype, reduce ion release, and restore tight junction integrity, addressing the cascade of barrier dysfunction. The dual-action therapy could provide a promising alternative to restore intestinal barrier function and enhance cholera treatment in resource-limited settings.
