Controlling Epithelial Polarity: A Human Enteroid Model for Host-Pathogen Interactions

Summary

Human enteroids—epithelial spheroids derived from primary gastrointestinal tissue—are a promising model to study pathogen-epithelial interactions. However, accessing the apical enteroid surface is challenging because it is enclosed within the spheroid. We developed a technique to reverse enteroid polarity such that the apical surface everts to face the media. Apical-out enteroids maintain proper polarity and barrier function, differentiate into the major intestinal epithelial cell (IEC) types, and exhibit polarized absorption of nutrients. We used this model to study host-pathogen interactions and identified distinct polarity-specific patterns of infection by invasive enteropathogens. Salmonella enterica serovar Typhimurium targets IEC apical surfaces for invasion via cytoskeletal rearrangements, and Listeria monocytogenes, which binds to basolateral receptors, invade apical surfaces at sites of cell extrusion. Despite different modes of entry, both pathogens exit the epithelium within apically extruding enteroid cells. This model will enable further examination of IECs in health and disease.

Graphical Abstract

Highlights

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  Enteroid polarity reversal by ECM protein removal enables apical epithelial access

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  Basal-out enteroids evert to apical-out polarity in a β1 integrin-dependent manner

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  Apical-out enteroids differentiate to the major intestinal epithelial cell types

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  An effective model to probe barrier integrity, nutrient uptake, and infection

Abstract

Co et al. describe a method to reverse human enteroid polarity, thus enabling access to the apical epithelium. Upon removing ECM scaffold proteins, basal-out enteroids evert to apical-out polarity in a β1 integrin-dependent manner. Demonstrated applications for this model include evaluating barrier integrity, monitoring nutrient uptake, and examining bacterial infection.