ABSTRACT
AIM: This study evaluated the influence of polymorphisms and cholesterol-lowering treatments on SCARB1 mRNA expression in peripheral blood mononuclear cells and in HepG2 and Caco-2 cells. METHODS: Blood samples were drawn from normolipidemic (NL, n = 166) and hypercholesterolemic (HC, n = 123) individuals to extract DNA and total RNA and to analyze the lipid profile. After a 4-week washout period, 98 HC individuals were treated with atorvastatin (10 mg/day/4 weeks) whereas 25 were treated with ezetimibe (10 mg/day/4 weeks), followed by simvastatin (10 mg/day/8 weeks) and simvastatin plus ezetimibe (10 mg each/day/4 weeks). HepG2 and Caco-2 cells were treated with atorvastatin, simvastatin and ezetimibe at various concentrations for 12 and 24 h and collected for RNA extraction. SCARB1 mRNA expression was measured by TaqMan® assay and SCARB1 c.4G> A, c.726 + 54C> T and c.1080C> T polymorphisms were detected by PCR-RFLP. RESULTS: High LDL cholesterol (> 160 mg/dL) values were associated with low baseline SCARB1 mRNA expression in PBMC. Allele T carriers for SCARB1 c.726+54C> T had lower basal SCARB1 transcription in PBMC (p < 0.05). Simvastatin, atorvastatin and ezetimibe treatments did not modify the SCARB1 mRNA level in PBMC from HC patients. Similarly, these cholesterol-lowering drugs did not modulate the SCARB1 expression in HepG2 and Caco-2 cells in spite of the concentration and time of exposure (p > 0.05). CONCLUSION: LDL cholesterol levels and SCARB1 c.726 + 54C> T are associated with low mRNA expression in mononuclear cells. Cholesterol-lowering drugs do not modulate SCARB1 expression in PBMC from HC subjects or in HepG2 and Caco-2 cells.
Subject(s)
Polymorphism, Genetic , Scavenger Receptors, Class B/genetics , Adult , Aged , Anticholesteremic Agents/administration & dosage , Atorvastatin , Azetidines/administration & dosage , Caco-2 Cells , DNA/metabolism , Ezetimibe , Female , Hep G2 Cells , Heptanoic Acids/administration & dosage , Humans , Hypercholesterolemia/blood , Leukocytes, Mononuclear/cytology , Lipids/chemistry , Male , Middle Aged , Pyrroles/administration & dosage , RNA, Messenger/metabolism , Simvastatin/administration & dosageABSTRACT
AIMS: The ATP-binding cassette transporters, ABCA1 and ABCG1, are LXR-target genes that play an important role in reverse cholesterol transport. We examined the effects of inhibitors of the cholesterol absorption (ezetimibe) and synthesis (statins) on expression of these transporters in HepG2 cells and peripheral blood mononuclear cells (PBMCs) of individuals with primary (and nonfamilial) hypercholesterolemia (HC). MATERIALS & METHODS: A total of 48 HC individuals were treated with atorvastatin (10 mg/day/4 weeks) and 23 were treated with ezetimibe (10 mg/day/4 weeks), followed by simvastatin (10 mg/day/8 weeks) and simvastatin plus ezetimibe (10 mg of each/day/4 weeks). Gene expression was examined in statin- or ezetimibe-treated and control HepG2 cells as well as PBMCs using real-time PCR. RESULTS: In PBMCs, statins and ezetimibe downregulated ABCA1 and ABCG1 mRNA expression but did not modulate NR1H2 (LXR-ß) and NR1H3 (LXR-α) levels. Positive correlations of ABCA1 with ABCG1 and of NR1H2 with NR1H3 expressions were found in all phases of the treatments. In HepG2 cells, ABCA1 mRNA levels remained unaltered while ABCG1 expression was increased by statin (1.0-10.0 µM) or ezetimibe (5.0 µM) treatments. Atorvastatin upregulated NR1H2 and NR1H3 only at 10.0 µM, meanwhile ezetimibe (1.0-5.0 µM) downregulated NR1H2 but did not change NR1H3 expression. CONCLUSION: Our findings reveal that lipid-lowering drugs downregulate ABCA1 and ABCG1 mRNA expression in PBMCs of HC individuals and exhibit differential effects on HepG2 cells. Moreover, they indicate that the ABCA1 and ABCG1 transcript levels were not correlated directly to LXR mRNA expression in both cell models treated with lipid-lowering drugs.
Subject(s)
Anticholesteremic Agents/pharmacology , Cholesterol/metabolism , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Leukocytes, Mononuclear/metabolism , Lipid Metabolism/drug effects , ATP-Binding Cassette Transporters/genetics , ATP-Binding Cassette Transporters/metabolism , Absorption/drug effects , Atorvastatin , Azetidines/pharmacology , Biological Transport/genetics , Dose-Response Relationship, Drug , Down-Regulation/drug effects , Drug Therapy, Combination , Ezetimibe , Female , Gene Expression/drug effects , Hep G2 Cells , Heptanoic Acids/pharmacology , Humans , Hypercholesterolemia/genetics , Leukocytes, Mononuclear/drug effects , Male , Middle Aged , Orphan Nuclear Receptors/metabolism , Pyrroles/pharmacology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Simvastatin/pharmacology , Up-Regulation/drug effectsABSTRACT
OBJECTIVE: The relationship between variants of the leptin gene (LEP) and obesity and metabolic biomarkers was investigated in Brazilian individuals. SUBJECTS AND METHODS: One-hundred-ten obese (BMI > 30 kg/m(2)) and 100 non-obese individuals (145 women and 65 men, aged 49 +/- 14 years) were randomly selected. Plasma leptin, glycemia, serum lipid measurements and LEP -2548G>A and 3'HVR polymorphisms were analyzed. RESULTS: The LEP -2548GG genotype was associated with a 2.2% and 2.0% increase in BMI (p = 0.009) and plasma leptin (p = 0.031), respectively. 3'HVR I/II (classes I/I+I/II) genotypes contributed with 1.8% of BMI values (p = 0.046). LEP I/G combined genotypes (I/IGG, I/IGA and I/IIGG) were associated with obesity, and increased BMI, waist circumference, leptin and triglycerides (p < 0.05). These relationships were found in women (p < 0.05) but not in men. LEP I/G combined genotypes were not associated with hypertension, hyperglycemia, dyslipidemia and coronary artery disease. CONCLUSIONS: LEP I/G combined genotypes are associated with obesity-related metabolic biomarkers and phenotype in a gender-dependent manner.
Subject(s)
Genetic Variation/genetics , Leptin/genetics , Obesity/genetics , Biomarkers/blood , Body Mass Index , Brazil , Epidemiologic Methods , Female , Humans , Leptin/blood , Male , Middle Aged , Obesity/bloodABSTRACT
OBJECTIVE: The relationship between variants of the leptin gene (LEP) and obesity and metabolic biomarkers was investigated in Brazilian individuals. SUBJECTS AND METHODS: One-hundred-ten obese (BMI > 30 kg/m²) and 100 non-obese individuals (145 women and 65 men, aged 49 ± 14 years) were randomly selected. Plasma leptin, glycemia, serum lipid measurements and LEP -2548G>A and 3'HVR polymorphisms were analyzed. RESULTS: The LEP -2548GG genotype was associated with a 2.2 percent and 2.0 percent increase in BMI (p = 0.009) and plasma leptin (p = 0.031), respectively. 3'HVR I/II (classes I/I+I/II) genotypes contributed with 1.8 percent of BMI values (p = 0.046). LEP I/G combined genotypes (I/IGG, I/IGA and I/IIGG) were associated with obesity, and increased BMI, waist circumference, leptin and triglycerides (p < 0.05). These relationships were found in women (p < 0.05) but not in men. LEP I/G combined genotypes were not associated with hypertension, hyperglycemia, dyslipidemia and coronary artery disease. CONCLUSIONS: LEP I/G combined genotypes are associated with obesity-related metabolic biomarkers and phenotype in a gender-dependent manner.
OBJETIVO: A relação entre as variantes do gene da leptina (LEP) e obesidade e biomarcadores metabólicos foi investigada em indivíduos brasileiros. SUJEITOS E MÉTOODS: Cento e dez indivíduos obesos (IMC > 30 kg/m²) e 100 não obesos (145 mulheres e 65 homens, idade 49 ± 14 anos) foram selecionados aleatoriamente. Leptina plasmática, glicemia, lípides séricos e polimorfismos LEP -2548G>A e 3'HVR foram analisados. RESULTADOS: O genótipo -2548GG foi associado com aumento de 2,2 por cento e 2,0 por cento no IMC (p = 0,009) e leptina plasmática (p = 0,031), respectivamente, enquanto os genótipos 3´HVR I/II (classes I/I+I/II) contribuíram com 1,8 por cento dos valores de IMC (p = 0,046). Os genótipos combinados LEP I/G (I/IGG, I/IGA e I/IIGG) foram associados com obesidade e IMC aumentado, circunferência abdominal, leptina e triglicérides aumentados (p < 0,05). Essas relações foram encontradas em mulheres (p < 0,05), mas não em homens. Os genótipos LEP I/G combinados não foram associados com hipertensão, hiperglicemia, dislipidemia e doença arterial coronariana. CONCLUSÕES: Genótipos combinados LEP I/G são associados com biomarcadores metabólicos e fenótipo de obesidade de forma gênero-dependente.
Subject(s)
Female , Humans , Male , Middle Aged , Genetic Variation/genetics , Leptin/genetics , Obesity/genetics , Body Mass Index , Brazil , Biomarkers/blood , Epidemiologic Methods , Leptin/blood , Obesity/bloodABSTRACT
This study investigated the effects of atorvastatin on ABCB1 and ABCC1 mRNA expression on peripheral blood mononuclear cells (PBMC) and their relationship with gene polymorphisms and lowering-cholesterol response. One hundred and thirty-six individuals with hypercholesterolemia were selected and treated with atorvastatin (10 mg/day/4 weeks). Blood samples were collected for serum lipids and apolipoproteins measurements and DNA and RNA extraction. ABCB1 (C3435T and G2677T/A) and ABCC1 (G2012T) gene polymorphisms were identified by polymerase chain reaction-restriction (PCR)-RFLP and mRNA expression was measured in peripheral blood mononuclear cells by singleplex real-time PCR. ABCB1 polymorphisms were associated with risk for coronary artery disease (CAD) (p<0.05). After atorvastatin treatment, both ABCB1 and ABCC1 genes showed 50% reduction of the mRNA expression (p<0.05). Reduction of ABCB1 expression was associated with ABCB1 G2677T/A polymorphism (p=0.039). Basal ABCB1 mRNA in the lower quartile (<0.024) was associated with lower reduction rate of serum low-density lipoprotein (LDL) cholesterol (33.4+/-12.4%) and apolipoprotein B (apoB) (17.0+/-31.3%) when compared with the higher quartile (>0.085: LDL-c=40.3+/-14.3%; apoB=32.5+/-10.7%; p<0.05). ABCB1 substrates or inhibitors did not affect the baseline expression, while ABCB1 inhibitors reversed the effects of atorvastatin on both ABCB1 and ABCC1 transporters. In conclusion, ABCB1 and ABCC1 mRNA levels in PBMC are modulated by atorvastatin and ABCB1 G2677T/A polymorphism and ABCB1 baseline expression is related to differences in serum LDL cholesterol and apoB in response to atorvastatin.
Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Gene Expression Regulation/genetics , Heptanoic Acids/pharmacology , Leukocytes, Mononuclear/metabolism , Multidrug Resistance-Associated Proteins/biosynthesis , Multidrug Resistance-Associated Proteins/genetics , Polymorphism, Genetic/genetics , Pyrroles/pharmacology , ATP Binding Cassette Transporter, Subfamily B , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Aged , Anticholesteremic Agents/pharmacology , Atorvastatin , Female , Gene Expression Regulation/drug effects , Humans , Leukocytes, Mononuclear/drug effects , Male , Middle Aged , Multidrug Resistance-Associated Proteins/metabolism , Polymorphism, Genetic/drug effectsABSTRACT
This study investigated the effects of atorvastatin on ABCB1 and ABCC1 mRNA expression on peripheral blood mononuclear cells (PBMC) and their relationship with gene polymorphismsand lowering-cholesterol response. One hundred and thirty-six individuals withhypercholesterolemia were selected and treated with atorvastatin (10 mg/day/4 weeks). Blood samples were collected for serum lipids and apolipoproteins measurements and DNA and RNA extraction. ABCB1 (C3435T and G2677T/A) and ABCC1 (G2012T) gene polymorphisms were identified by polymerase chain reaction-restriction (PCR)-RFLP and mRNA expression was measured in peripheral blood mononuclear cells by singleplex real-time PCR. ABCB1 polymorphisms were associated with risk for coronary artery disease (CAD) ( p 0.085: LDL-c = 40.3 14.3%; apoB = 32.5 10.7%; p < 0.05). ABCB1 substrates or inhibitors did not affect the baseline expression, while ABCB1 inhibitors reversedthe effects of atorvastatin on both ABCB1 and ABCC1 transporters. In conclusion, ABCB1 and ABCC1 mRNA levels in PBMC are modulated by atorvastatin and ABCB1 G2677T/A polymorphism and ABCB1 baseline expression is related to differences in serum LDL cholesterol and apoB in response to atorvastatin.
Subject(s)
Gene Expression , Pharmacogenetics , Polymorphism, GeneticABSTRACT
A homeostase do colesterol é mediada por proteínas envolvidas na absorçao (NPC1L1), regulação (SREBP1, SREBP2, SCAP), síntese (HMGCR) e remoção plasmática (LDLR). Os fármacos inibidores da síntese (vastatinas) e absorção (ezetimiba) do colesterol são potentes agentes hipocolesterolemiantes. Alteracões em vários genes têm sido associadas a diferenças na resposta a diversos agentes terapêuticos. Com a finalidade de estudar os efeitos de hipolipemiantes e polimorfismos sobre a expressão dos genes HMGCR, LDLR, SREBF1a, SREBF2, SCAP e NPC1L1, foram selecionados 25 indivíduos com hipercolesterolemia familial (HF), 72 com hipercolesterolemia não familial (HNF) e 125 indivíduos normolipidêmicos e sem doença cardiovascular (NL). Os indivíduos HF foram tratados com sinvastatina (40 mg/dia/4 sem) combinada ou não com ezetimiba (10 mg/dia/4sem) e os HNF foram tratados com atorvastatina (10 mg/dia/4sem). Amostras de sangue foram obtidas antes e após o tratamento para a extração de DNA e RNA e analise do perfil lipídico sérico. A expressão de mRNA dos genes SREBF1a, SREBF2, SCAP, HMGCR, LDLR e NPC1L1 em células mononucleares do sangue periférico (CMSP) foi determinada por RT-PCR em tempo real empregando-se o gene da GAPD como controle endógeno...
Subject(s)
Humans , Male , Adult , Cholesterol/analysis , Cholesterol/genetics , Cholesterol/metabolism , Gene Expression , Pharmacogenetics/methods , Hypercholesterolemia/metabolism , Hypercholesterolemia/drug therapy , Homeostasis/genetics , Blood Specimen Collection , Electrophoresis , Polymorphism, Genetic/genetics , Polymerase Chain Reaction/methodsABSTRACT
BACKGROUND: The transcription factors SREBP1 and SCAP are involved in intracellular cholesterol homeostasis. Polymorphisms of these genes have been associated with variations on serum lipid levels and response to statins that are potent cholesterol-lowering drugs. We evaluated the effects of atorvastatin on SREBF1a and SCAP mRNA expression in peripheral blood mononuclear cells (PBMC) and a possible association with gene polymorphisms and lowering-cholesterol response. METHODS: Fifty-nine hypercholesterolemic patients were treated with atorvastatin (10 mg/day for 4 weeks). Serum lipid profile and mRNA expression in PBMC were assessed before and after the treatment. Gene expression was quantified by real-time PCR using GAPD as endogenous reference and mRNA expression in HepG2 cells as calibrator. SREBF1 -36delG and SCAP A2386G polymorphisms were detected by PCR-RFLP. RESULTS: Our results showed that transcription of SREBF1a and SCAP was coordinately regulated by atorvastatin (r=0.595, p<0.001), and that reduction in SCAP transcription was associated with the 2386AA genotype (p=0.019). Individuals who responded to atorvastatin with a downregulation of SCAP had also a lower triglyceride compared to those who responded to atorvastatin with an upregulation of SCAP. CONCLUSION: Atorvastatin has differential effects on SREBF1a and SCAP mRNA expression in PBMC that are associated with baseline transcription levels, triglycerides response to atorvastatin and SCAP A2386G polymorphism.
