Gut microbiota dysbiosis affects intestinal sensitivity through epithelium-to-neuron signaling: novel insights from colon organoid-based model to improve visceral pain therapy

Chronic gastrointestinal pain is a hallmark of most intestinal pathologies, yet effective treatments remain elusive given the complexity of the underlying mechanisms. Aiming to investigate the intestinal epithelium contribution to visceral pain modulation in dysbiosis context, we first demonstrated that intracolonic instillation of microbe-free faecal supernatants from mice with post-inflammatory dysbiosis induced by dextran sodium sulfate (FS DSS ) provokes visceral hypersensitivity in recipient mice. Epithelium involvement in the response to FS DSS was thoroughly analyzed through a novel in vitro approach comprising murine epithelial colon organoids and primary dorsal root ganglia (DRG) neurons. FS DSS treatment induced growth and metabolic impairment in colon organoids, which reveals a dysbiosis-driven epithelial dysfunction. Notably, the combination of FS DSS and conditioned medium from FS DSS -treated colon organoids increased DRG neuron excitability, implicating a synergism between microbial and epithelial products in visceral sensitivity regulation. By investigating the underlying signaling, metabolomic analysis revealed reduced levels of short chain fatty acids in FS DSS whereas transcriptomic analysis of FS DSS - treated colon organoids showed the dysregulated expression of several signaling factors. These findings provide novel insights into the role of gut epithelium in the modulation of sensory neuron excitability under dysbiosis conditions, emphasizing that targeting epithelial-neuronal signaling might represent a promising therapeutic strategy for visceral pain management.