The recruitment and activation of PMN-MDSC to the mid-proximal colon of BRAFV600E relative to wild-type mice after colonization with Enterotoxigenic Bacteroides fragilis. Mus musculus

Enterotoxigenic Bacteroides fragilis (ETBF) is known to induce colitis in the distal colon of wild-type (WT) mice. In mice bearing the BRAFV600ELgr5Cre (BL) genotype, ETBF also causes colitis in the colon adjacent to the proximal folds or mid-proximal (MP) region. Unlike the WT mice, ETBF induced a significant increase in CD45+CD11b+Ly6G-Ly6C-F4/80lowI-A/Elow (F4/80lowI-A/Elow) immune cells in the MP colon. We characterized these cells in order to better understand their unique contribution to disease progression in ETBF colonized mice bearing the BRAFV600E mutation.Overall design: RNAseq was performed on cell-sorted CD45+CD11b+Ly6G-Ly6C-F4/80lowI-A/Elow versus CD45+CD11b+Ly6G-Ly6C-F4/80highI-A/Ehigh cells from the midproximal colon region of BL and WT mice 2 weeks after ETBF inoculation. Analysis revealed that the ETBF colonized BL mice were enriched in granulocytic myeloid-derived suppressor cells (MDSC), polymorphonuclear cells (PMN)-MDSC.