Cell-autonomous transformation of Lgr5-positive intestinal stem cells into gastric stem cells upon loss of transcription factor Cdx2. Mus musculus

Stomach and intestinal adult epithelia harbor stem cells that are responsible for their continuous regeneration. Stomach and intestinal stem cells differ in their differentiation program and in the gene repertoire that they express. We show that single adult Lgr5-positive stem cells, isolated from 3D cultured small intestinal organoids, require Cdx2 to maintain their intestinal identity and are converted cell-autonomously into stomach-pyloric stem cells in the absence of this transcription factor. Overall design: In order to obtain Cdx2null intestinal stem cells carrying the Lgr5-EGFP marker, 5-6 days old small intestinal organoids generated from Cdx2-/fl/Lgr5-EGFP-Ires-CreERT2 mice were incubated with 1 µM of 4-hydroxytamoxifen in intestinal culture medium for 16h to activate the Cre recombinase. Controls were 4-hydroxytamoxifen-untreated small intestinal (Control SI) and stomach (Control Sto) organoids issued from mice with the same genotype. The organoids were dissociated and sorted for EGFPhi. Cdx2null, Control SI and Control Sto clonal organoids were generated and expanded from Lgr5-EGFPhi single cells in stomach specific culture medium (ENRWfg) and RNA was isolated for RNA-Seq analysis. Cdx2+ Stomach (Sto) organoids were generated by infection of the wild type stomach organoids with lentiviral stock expressing Cdx2. They were cultured in stomach medium (ENRWfg) and RNA was isolated for RNA-Seq analysis