Rationale: We and others have demonstrated that anthocyanins have antiatherogenic capability. Because intact anthocyanins are absorbed very poorly, the low level of circulating parent anthocyanins may not fully account for their beneficial effect. We found recently that protocatechuic acid (PCA), a metabolite of cyanidin-3 to 0-β-glucoside (Cy-3-G), has a remarkable antiatherogenic effect.
Objective: To investigate whether mouse gut microbiota metabolizes Cy-3-G into PCA and to determine whether and how PCA contributes to the antiatherogenic potency of its precursor, Cy-3-G.
Methods and results: PCA was determined as a gut microbiota metabolite of Cy-3-G in ApoE(-/-) mice, verified by the utilization of antibiotics to eliminate gut microbiota and further microbiota acquisition. PCA but not Cy-3-G at physiologically reachable concentrations promoted cholesterol efflux from macrophages and macrophage ABCA1 and ABCG1 expression. By conducting a miRNA microarray screening, we revealed that expression of miRNA-10b in macrophages can be reduced by PCA. Functional analyses demonstrated that miRNA-10b directly represses ABCA1 and ABCG1 and negatively regulates cholesterol efflux from murine- and human-derived macrophages. Further in vitro and ex vivo analyses verified that PCA accelerates macrophage cholesterol efflux, correlating with the regulation of miRNA-10b-ABCA1/ABCG1 cascade, whereas Cy-3-G consumption promoted macrophage RCT and regressed atherosclerotic lesion in a gut microbiotaendependent manner.
Conclusions: PCA, as the gut microbiota metabolite of Cy-3-G, exerts the antiatherogenic effect partially through this newly defined miRNA-10b-ABCA1/ABCG1-cholesterol efflux signaling cascade. Thus, gut microbiota is a potential novel target for atherosclerosis prevention and treatment.