Circadian clock at the interface of mucosal immunity, gut microbiota and epithelial barrier in inflammatory bowel disease

Figure 3 Bidirectional crosstalk between the circadian clock and gut microbiota, including microbial diurnal oscillations and metabolite signaling. The bidirectional clock-microbiota framework is strongly supported by preclinical and mechanistic studies, whereas human interventional evidence remains limited. Future trials incorporating circadian endpoints are needed to validate clinical translation. IBD: Inflammatory bowel disease; SCFA: Short-chain fatty acid; IAA: Indole-3-acetic acid; BMAL1: Brain and muscle ARNT-like 1; PER2: Period 2; AHR: Aryl hydrocarbon receptor.