title: The lipoprotein/lipid profile is modulated by a gene-diet interaction effect between polymorphisms in the liver X receptor-alpha and dietary cholesterol intake in French-Canadians.
abstract: Genetic and nutritional factors interact together and modulate the plasma lipid profile. We identified variations in the gene encoding the liver X receptor alpha (LXRalpha) and investigated their effects on the plasma lipoprotein/lipid profile. We also examined whether the association between cholesterol intake and plasma lipid profile was modulated by LXRalpha variants. The LXRalpha gene was sequenced in thirty-five French-Canadian men with high plasma total cholesterol (>5.0 mmol/l) and LDL-cholesterol (>3.5 mmol/l) concentrations. dietary cholesterol was obtained from a food-frequency questionnaire. The LXRalpha c.-115G>A, c.-840C>A and c.-1830T>C genotypes were determined by direct sequencing in 732 subjects. Molecular screening of the LXRalpha gene revealed sixteen variants. Genotypes c.-115G>A, c.-840C>A and c.-1830T>C (rare allele frequency of 14.3%, 14.2% and 11.0%, respectively) were analysed further. Plasma total cholesterol concentrations were higher in carriers of the -115A, -840A and -1830C allele, compared with the -115G/G, -840C/C and -1830T/T homozygotes (P< or =0.05). In a model including the c.-115G>A polymorphism, cholesterol intake, the interaction term c.-115G>A x cholesterol intake (mg/d) and covariates, LXRalpha-115G>A explained 1.8% and 2.1% of the variance in total cholesterol and LDL-cholesterol concentrations (P=0.02 and P=0.01), whereas the interaction term explained 2.9% (P=0.002) and 2.8% (P=0.005), respectively. When subjects were divided into four groups according to the median of cholesterol (290.8 mg) and -115G>A genotypes, high cholesterol intake was associated with higher cholesterol levels in -115A carriers. Similar results were observed for c.-840C>A and c.-1830T>C. These results suggest that cholesterol intake interacts with LXRalpha variants to modulate the plasma lipid profile.
authors.affiliation: Lipid Research Center, CHUQ-CHUL, Ste-foy, Québec, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Robitaille
authors.forename: Alain
authors.initials: A
authors.lastname: Houde
authors.forename: Simone
authors.initials: S
authors.lastname: Lemieux
authors.forename: Daniel
authors.initials: D
authors.lastname: Gaudet
authors.forename: Louis
authors.initials: L
authors.lastname: Pérusse
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Vohl
mesh_terms: D000328:Adult; D000367:Age Factors; D000483:Alleles; D001499:Bayes Theorem; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D008078:Cholesterol, LDL / Q000097:blood; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D002149:Energy Intake; D005260:Female; D005602:France / Q000208:ethnology; D005787:Gene Frequency; D006579:Heterozygote; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D008055:Lipids / Q000097:blood*; D008074:Lipoproteins / Q000097:blood*; D008099:Liver / Q000378:metabolism; D000071518:Liver X Receptors; D008297:Male; D008875:Middle Aged; D057093:Orphan Nuclear Receptors; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D011792:Quebec; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D012737:Sex Factors; D044465:White People
chemical_list: D002791:Cholesterol, Dietary; D008078:Cholesterol, LDL; D004268:DNA-Binding Proteins; D008055:Lipids; D008074:Lipoproteins; D000071518:Liver X Receptors; C000605213:NR1H3 protein, human; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear