Regulation of genes involved intestinal cholesterol metabolism by polyphenol‐rich black currant extract in Caco‐2 cells

Abstract

We investigated the effect of blackcurrant extract (BCE) containing 25% polyphenols on the regulation of genes involved in intestinal cholesterol metabolism with a specific focus on transintestinal cholesterol efflux (TICE). As TICE provides a non‐biliary route for cholesterol excretion, TICE activation can lower plasma cholesterol levels. Caco‐2 cells, a human intestinal cell line, were incubated with BCE (50 or 100 μg/mL) for 24 h for gene expression analysis. BCE significantly decreased the expression of genes for cholesterol synthesis (3‐hydroxy‐3‐methylglutaryl coenzyme A reductase and sterol regulatory element binding protein 2), for apical cholesterol uptake (Niemann‐Pick C1 Like 1), and for basolateral cholesterol efflux (ATP binding cassette transporter (ABC) A1). Decreases in the protein levels of these genes were confirmed by Western blot analysis. In contrast, BCE significantly increased mRNA and protein levels of ABCG5/G8, which facilitate apical cholesterol efflux to the intestinal lumen. Furthermore, BCE markedly increased protein levels of LDL receptor. Our data suggest that BCE may activate TICE pathway by increasing LDL uptake into enterocytes and by facilitating the efflux of LDL‐derived cholesterol to the luminal side via increased ABCG5/G8 expression in the intestine.Grant Funding Source: College of Agriculture and Natural Resources at UCONN and National Research Foundation of Korea