Spotlight: Enteroendocrine cells regulate intestinal barrier permeability

Introduction

The intestinal epithelium forms a selective barrier that facilitates nutrient absorption while blocking harmful substances and pathogens. Disruption of this barrier contributes to gastrointestinal diseases such as IBD and infections. While the roles of immune cells and epithelial tight junctions in barrier regulation are well understood, the contribution of enteroendocrine cells (ECCs), known for hormone secretion and nutrient sensing, remains unclear. This study explores whether ECCs directly regulate intestinal barrier function using ECC-deficient models and human organoids.

Main Points

• The authors generated organoids from wild-type and NEUROG3-null human pluripotent stem cells, which lack the transcription factor required for ECC differentiation.
• Organoid-derived monolayers were cultured on Transwell filters to assess the impact of ECC absence on barrier integrity, using high-Wnt media (promoting stemness) and low-Wnt media (promoting differentiation).
• Trans-epithelial electrical resistance (TEER) measurements were significantly lower in ECC-deficient monolayers compared to controls especially in differentiated cultures, where increased permeability to Luciferase Yellow (LY) was observed, indicating compromised barrier function.
• The addition of ECC derived hormone peptide tyrosine-tyrosine (PYY) improved both TEER and reduced the permeability to LY. Similar results were observed with the Somatostatin analogue, Octreotide.
• ECC-deficient monolayer exhibited reduced expression of tight junction proteins, such as ZO-1 and Occludin.
• Adding ECC-derived hormones protected ECC-deficient monolayers from the effects of TNFα treatment, a pro-inflammatory cytokine known to disrupt barrier integrity.
• These protective effects were independent of tight junction protein levels.

Conclusion

In conclusion, enteroendocrine cells are essential for maintaining barrier integrity through paracrine signals, particularly PYY. ECCs disfunction may contribute to barrier-related diseases, highlighting their potential as therapeutic targets.

EPISTEM SERVICES

Organoids

Epistem offers intestinal organoid and organoid-derived monolayer models that replicate human intestinal tissue for studying biology, disease, and drug responses. Organoids can be assessed in 3D or as 2D monolayers for direct epithelial access. These models support a variety of readouts:

• Cellular assays: viability, proliferation, and morphology
• Imaging techniques: immunofluorescence (IF), immunohistochemistry (IHC)
• Gene expression profiling: qPCR, and Next-Generation Sequencing (NGS)
• Protein and cytokine analysis: ELISA, Multiplex Cytokine profiling
• Cellular phenotyping: Flow Cytometry
• Spatial transcriptomics: in situ hybridization (RNAscope)

Developed by a team with decades of experience in in vivo GI research, our models are designed to reflect in vivo biology and enhance translational relevance. This combined in vitro and in vivo expertise supports therapeutic development in gastroenterology, oncology, inflammation, and infection.