Gut microbiome and metabolomic profiles reveal the antiatherosclerotic effect of indole-3-carbinol in high-choline-fed ApoE-/- mice

The metabolites produced from choline contribute to atherosclerosis (AS) pathogenesis, and the gut microbiota is redundantly essential for this process. Indole-3-carbinol (I3C), found in Cruciferous vegetables such as broccoli, cabbage, cauliflower and brussels sprouts, helps prevent hyperlipidemia, maintain the gut microbiota balance, and decrease the production of trimethylamine-N-oxide (TMAO) from choline in the diet. The objective of this research was to investigate the impact of I3C on choline-induced AS and to further elucidate the underlying mechanism involved. AS models of high-choline-induced ApoE−/− mice and TMAO-promoted foamy macrophages were established to observe the effect of I3C on the formation of atherosclerotic plaques and foam cells and changes in AS-related indicators (including blood biochemical indicators, TMA, TMAO, SRA, and SRB1), and integrated analyses of the microbiome and metabolome were used to reveal the mechanism of action of I3C. We found that I3C inhibited high-choline-induced atheroma formation (50-100 mg/kg/d, in vivo) and slightly improved the lipid profile (15 mg/kg/d, in vivo). Moreover, I3C suppressed lipid influx at a concentration of 40 µmol/L in vitro, enhanced the diversity of the gut microbiota and the abundance of the phylum Verrucomicrobia, and consequently modified the gut microbial metabolites at a dosage of 50 mg/kg/day in the mice. Associative analyses based on microbiome and metabolomics revealed that 1-methyladenosine was a key modulator of the protective effect of I3C against AS in high-choline-induced ApoE−/−mice. These findings demonstrate for the first time that I3C ameliorates AS progression through remodeling of the gut microbiome and metabolomics, which paves the way for the possible therapeutic use of this vegetable-derived natural compound and may reduce the clinical severity of AS-related cardiovascular diseases.