SUCNR1 and inflammatory bowel disease: SUCNR1 (GPR91), a succinate-specific G-protein-coupled receptor expressed on macrophages, dendritic cells, intestinal epithelial cells, kidneys, liver, and adipose tissue, engages succinate to launch pro-inflammatory cascades involving NF-κB and MAPK signaling (8), thereby serving as a metabolic checkpoint linking succinate accumulation to IBD pathogenesis (9, 10).