Beneficial effects of Enterococcus faecalis in hypercholesterolemic mice on cholesterol transportation and gut microbiota

Hypercholesterolemia plays a critical role in the development of atherosclerosis and cardiovascular diseases. Many works have been reported that gut microbiota could affect hypercholesterolemia through cholesterol metabolism. However, the role of gut microbiota on cholesterol transportation remains unclear. In this study, 8-week-old C57BL/6J mice were fed with high-cholesterol diet to build the hypercholesterolemic mice. Then, the hypercholesterolemic mice got the oral administration of Enterococcus faecalis ATCC19433 at a dose of 109 CFU/mL/day or PBS with high-cholesterol diet for 4 weeks. Serum was collected to detect the concentration of total cholesterol (TC). Meanwhile, pathology, histology, real-time polymerase chain reaction, Western blot, and immunofluorescence were used to evaluate the expression of ABCG5 and ABCG8 in the liver and small intestine. We also analyzed the composition of gut microbiota through high-throughput sequencing method. Oral administration of E. faecalis ATCC19433 significantly decreased the concentration of serum cholesterol in hypercholesterolemic mice. Furthermore, E. faecalis ATCC19433 reduced the concentration of liver cholesterol and improved cholesterol by increasing the expression of ABCG5 and ABCG8. Moreover, oral administration of E. faecalis ATCC19433 modulated the composition of gut microbiota and increased the counts of Lactobacillus, Bifidobacterium, and Akkermansia. Our results showed that E. faecalis ATCC19433 could exert hypocholesterolemic effect on hypercholesterolemic mice by improving transporter ABCG5 and ABCG8. E. faecalis ATCC19433 maybe contribute to the transportation of cholesterol potentially and modulate the composition of gut microbiota.