ETEC heat-labile toxin promotes β-catenin stabilization and transcriptional reprogramming to disrupt intestinal...

Enterotoxigenic Escherichia coli (ETEC), defined by their production of heat-labile (LT) and heat-stable (ST) enterotoxins, are a common cause of acute diarrheal illness in children from low- and middle- income countries, and are also linked to long-term sequelae such as malnutrition, and growth impairment. While the mechanisms underlying toxin-mediated acute diarrhea are known, the molecular events involved in ETEC related sequelae remain unclear. Here, we demonstrate that the ETEC heat-labile toxin (LT) profoundly remodels intestinal epithelial composition and function through modulation of WNT/β-catenin signaling. Using human ileal enteroids, we demonstrate that LT stabilizes β-catenin independently of WNT ligands, promotes its nuclear accumulation, and enhances TCF/LEF-driven transcription. Single-cell transcriptomic analyses reveal that LT increases intestinal proliferation by enhancing cell cycle activity across all epithelial lineages, thus disrupting epithelial composition by expanding proliferative progenitor populations at the expense of absorptive enterocytes. Simultaneously, LT impairs epithelial maturation and suppresses transcriptional programs required for nutrient absorption and differentiation. Together, these findings identify LT as a potent driver of intestinal epithelial reprogramming, providing mechanistic insight into how ETEC infection may drive long-term consequences beyond acute diarrhea and may inform strategies to prevent major sequelae, including malnutrition, that affect millions of children worldwide.