Bioluminescent Imaging Reveals Diet-Dependent Coupling of Microbial Hydrogen Sulfide Production and Host Fatty Acid Uptake In Vivo

High Resolution Image Download MS PowerPoint Slide Hydrogen sulfide (H 2 S) is a gaseous mediator whose effects depend on concentration and location, with most gut H 2 S shaped by microbial metabolism and diet. How specific dietary components modulate microbial H 2 S in vivo remains unclear due to a lack of longitudinal, noninvasive tools. We established a dual bioluminescent imaging platform to monitor microbial H 2 S production alongside host fatty acid uptake in vivo . A panel of probes was synthesized and screened to select an H 2 S-selective probe optimized for in vitro and in vivo use. Using this platform, elevated H 2 S was observed only when a cysteine-rich diet was combined with fermentable inulin, not with nonfermentable cellulose. This increase coincided with shifts in the microbial community, altered gut morphology, and enhanced host fatty acid uptake. The dual imaging approach provides a versatile framework to dissect diet-dependent microbial metabolism and host responses and can be applied to metabolites not accessible by conventional end point analyses.