BACKGROUND & AIMS: The bile acid pool influences intestinal cholesterol absorption because this process is strictly dependent on micellar solubilization, which is disrupted by plant sterols (PS). Plasma lipid variation relates to promoter variant -204A > C (rs3808607) of the CYP7A1 gene encoding for 7α-hydroxylase, an enzyme for bile acid synthesis. We hypothesized that this polymorphism would be associated with variability in lipid responses to PS. METHODS: We investigated 67 subjects (31 AA and 36 AC + CC) with lipid responses to PS documented in two studies. To assess the functionality of the -204A > C variant, electrophoretic mobility gel shift assays were performed and luciferase reporter plasmids containing the promoter were transfected into HepG2 cells. RESULTS: Compared to AA-subjects, C-carriers showed significantly higher adjusted mean reductions in total cholesterol (0.14 versus 0.43 mmol/L, P = 0.042) and increases in lathosterol-to-cholesterol ratios (0.10 versus 0.75, P = 0.013). The C-construct caused a 78% promoter activity increase and gel-shift assays showed lower affinity for nuclear transcription factors, while in silico experiments predicted a binding site for inhibitory nuclear factors RXR-CAR. CONCLUSIONS: Results suggest that promoter -204A > C variant is associated with enhanced CYP7A1 activity. Increased intestinal bile acids and ensuing more efficient cholesterol absorption might explain why C-allele carriers show enhanced cholesterol lowering and increased feedback cholesterol synthesis to PS intervention.
RCT Entities:
BACKGROUND & AIMS: The bile acid pool influences intestinal cholesterol absorption because this process is strictly dependent on micellar solubilization, which is disrupted by plant sterols (PS). Plasma lipid variation relates to promoter variant -204A > C (rs3808607) of the CYP7A1 gene encoding for 7α-hydroxylase, an enzyme for bile acid synthesis. We hypothesized that this polymorphism would be associated with variability in lipid responses to PS. METHODS: We investigated 67 subjects (31 AA and 36 AC + CC) with lipid responses to PS documented in two studies. To assess the functionality of the -204A > C variant, electrophoretic mobility gel shift assays were performed and luciferase reporter plasmids containing the promoter were transfected into HepG2 cells. RESULTS: Compared to AA-subjects, C-carriers showed significantly higher adjusted mean reductions in total cholesterol (0.14 versus 0.43 mmol/L, P = 0.042) and increases in lathosterol-to-cholesterol ratios (0.10 versus 0.75, P = 0.013). The C-construct caused a 78% promoter activity increase and gel-shift assays showed lower affinity for nuclear transcription factors, while in silico experiments predicted a binding site for inhibitory nuclear factors RXR-CAR. CONCLUSIONS: Results suggest that promoter -204A > C variant is associated with enhanced CYP7A1 activity. Increased intestinal bile acids and ensuing more efficient cholesterol absorption might explain why C-allele carriers show enhanced cholesterol lowering and increased feedback cholesterol synthesis to PS intervention.
Authors: Peter J H Jones; Maryam Shamloo; Dylan S MacKay; Todd C Rideout; Semone B Myrie; Jogchum Plat; Jean-Baptiste Roullet; David J Baer; Kara L Calkins; Harry R Davis; P Barton Duell; Henry Ginsberg; Helena Gylling; David Jenkins; Dieter Lütjohann; Mohammad Moghadasian; Robert A Moreau; David Mymin; Richard E Ostlund; Rouyanne T Ras; Javier Ochoa Reparaz; Elke A Trautwein; Stephen Turley; Tim Vanmierlo; Oliver Weingärtner Journal: Nutr Rev Date: 2018-10-01 Impact factor: 7.110
Authors: Barbara Walther; Aaron M Lett; Alessandra Bordoni; Lidia Tomás-Cobos; Juan Antonio Nieto; Didier Dupont; Francesca Danesi; Danit R Shahar; Ana Echaniz; Roberta Re; Aida Sainz Fernandez; Amélie Deglaire; Doreen Gille; Alexandra Schmid; Guy Vergères Journal: Mol Nutr Food Res Date: 2019-10-01 Impact factor: 5.914