Organoids as models to study probiotics

For decades, scientists have exploited cancer cell lines as models to study host-pathogen interactions and intestinal functions in vitro. Such monotypic cell models have led to important discoveries but have notable limitations. Immortalized cell lines display biological variations such as aneuploidy, chromosome rearrangements or mutations leading to poorly reproducible results, even for the same cell line.
Organoids are gaining considerable interest as alternative models of the intestine due to their close resemblance to structural, cellular and functional complexity found in vivo. However, the three-dimensional geometry of stem-cell derived intestinal organoids limits easy access to the apical epithelium for investigating the influence of probiotics, bioactive and toxic compounds on barrier function and permeability. Here we present a new robust method for generating confluent intestinal cell monolayers from single-cell suspensions of enzymatically-dissociated organoids. Confluent polarised monolayers containing tight-junctions were formed in three days and could be used in experiments for up to two weeks. Multilineage differentiation of the ileal stem cells was demonstrated by immunohistochemistry, and RT-qPCR of cell-specific transcripts. Furthermore, we showed that adult stem-cell derived ileal organoids maintain location-specific transcriptional programs during long-term in vitro culture.