Therapeutic response to ezetimibe in C57BL/6 mice is mediated by changes in NPC1L1, ABCG5 and ABCG8 expression in the enterocyte

Proteins NPC1L1, ABCG5 and ABCG8 are involved in the intestinal absorption of cholesterol. Ezetimibe inhibits this process by blocking NPC1L1, however, its effect on ABCG5 and ABCG8 is not yet clear. Thus, the objective of this study was to evaluate in C57BL/6 mice with diet-induced hypercholesterolemia treated with ezetimibe, the expression of NPC1L1, ABCG5 and ABCG8 by real time PCR and Western blot, in 3 groups of animals: 1, diet hypercholesterolemic D12336, 2, D12336 diet plus 5 mg/kg/day of ezetimibe, 3, diet control. The serum level of total cholesterol was significantly different between groups (control: 1.85 +/- 0.49 mmol/L; diet D12336: 3.11 +/- 0.73 mmol/L; ezetimibe: 2.11 +/- 0.50 mmol/L, P = 0.001). NPC1L1 gene expression increased 5.4-fold in the group receiving the diet D12336 (P = 0.003). Furthermore, the gene expression of ABCG5 and ABCG8 was not different in the group with hypercholesterolemia (P = 0.239 and P = 0.201, respectively). After treatment with ezetimibe, ABCG5 gene expression was increased 15.6 times (P = 0.038). No significant differences in gene expression of NPC I L I (P = 0.134) and ABCG8 (P = 0.067). Regarding protein expression, the D12336 diet increased the levels of expression of NPC1L1 (P = 0.022) and ABCG5 (P = 0.008), treatment with ezetimibe increased the levels of NPC1L1 (P = 0.048) and reduced levels of ABCG5 (P = 0.036) and ABCG8 (P = 0.016). In conclusion, our results suggest that both hypercholesterolemic diet as treatment with ezetimibe, in an experimental model, affect the expression levels of NPC1L1, ABCG5 and ABCG8, suggesting that ABCG5 and ABCG8 are involved in lipid-lowering response to this drug. However, the mechanism by which this interaction is explained requires further study.