SLC9A3 and colitis: In recent studies with gnotobiotic RAG1−/− or IL10−/− mice with fecal microbiota transfer from WT or NHE3-deficient mice, we demonstrated a causative relationship between NHE3-induced dysbiosis and colitis, with accelerated onset, and more severe inflammatory responses in mice colonized with microbiota from NHE3−/− mice21.