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Xu C, Liu Y, Gong Y, Duan X, Tang X, Zhang M, Pang D, Yu L, Wei H, Ouyang H. Overexpression of NPC1L1 in the livers of transgenic Bama miniature pigs accelerates lipid peroxidation. Genes Genomics 2015. [DOI: 10.1007/s13258-014-0235-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Ziada A, Schwarz UI, DeGorter MK, Tirona RG, Ban MR, Kim RB, Hegele RA. Incremental Lowering of Low-Density Lipoprotein Cholesterol With Ezetimibe 20 mg vs 10 mg Daily in Patients Receiving Concomitant Statin Therapy. Can J Cardiol 2013; 29:1395-9. [DOI: 10.1016/j.cjca.2013.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/08/2013] [Accepted: 08/08/2013] [Indexed: 10/26/2022] Open
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Naples M, Baker C, Lino M, Iqbal J, Hussain MM, Adeli K. Ezetimibe ameliorates intestinal chylomicron overproduction and improves glucose tolerance in a diet-induced hamster model of insulin resistance. Am J Physiol Gastrointest Liver Physiol 2012; 302:G1043-52. [PMID: 22345552 PMCID: PMC4380478 DOI: 10.1152/ajpgi.00250.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ezetimibe is a cholesterol uptake inhibitor that targets the Niemann-Pick C1-like 1 cholesterol transporter. Ezetimibe treatment has been shown to cause significant decreases in plasma cholesterol levels in patients with hypercholesterolemia and familial hypercholesterolemia. A recent study in humans has shown that ezetimibe can decrease the release of atherogenic postprandial intestinal lipoproteins. In the present study, we evaluated the mechanisms by which ezetimibe treatment can lower postprandial apoB48-containing chylomicron particles, using a hyperlipidemic and insulin-resistant hamster model fed a diet rich in fructose and fat (the FF diet) and fructose, fat, and cholesterol (the FFC diet). Male Syrian Golden hamsters were fed either chow or the FF or FFC diet ± ezetimibe for 2 wk. After 2 wk, chylomicron production was assessed following intravenous triton infusion. Tissues were then collected and analyzed for protein and mRNA content. FFC-fed hamsters treated with ezetimibe showed improved glucose tolerance, decreased fasting insulin levels, and markedly reduced circulating levels of TG and cholesterol in both the LDL and VLDL fractions. Examination of triglyceride (TG)-rich lipoprotein (TRL) fractions showed that ezetimibe treatment reduced postprandial cholesterol content in TRL lipoproteins as well as reducing apoB48 content. Although ezetimibe did not decrease TRL-TG levels in FFC hamsters, ezetimibe treatment in FF hamsters resulted in decreases in TRL-TG. Jejunal apoB48 protein expression was lower in ezetimibe-treated hamsters. Reductions in jejunal protein levels of scavenger receptor type B-1 (SRB-1) and fatty acid transport protein 4 were also observed. In addition, ezetimibe-treated hamsters showed significantly lower jejunal mRNA expression of a number of genes involved in lipid synthesis and transport, including srebp-1c, sr-b1, ppar-γ, and abcg1. These data suggest that treatment with ezetimibe not only inhibits cholesterol uptake, but may also alter intestinal function to promote improved handling of dietary lipids and reduced chylomicron production. These, in turn, promote decreases in fasting and postprandial lipid levels and improvements in glucose homeostasis.
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Affiliation(s)
- Mark Naples
- 1Molecular Structure and Function, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada;
| | - Chris Baker
- 1Molecular Structure and Function, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada;
| | - Marsel Lino
- 1Molecular Structure and Function, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada;
| | | | | | - Khosrow Adeli
- 1Molecular Structure and Function, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada;
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Kumar P, Malhotra P, Ma K, Singla A, Hedroug O, Saksena S, Dudeja PK, Gill RK, Alrefai WA. SREBP2 mediates the modulation of intestinal NPC1L1 expression by curcumin. Am J Physiol Gastrointest Liver Physiol 2011; 301:G148-55. [PMID: 21527728 PMCID: PMC3129937 DOI: 10.1152/ajpgi.00119.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Curcumin, the major phenolic compound in the spice turmeric, exhibits numerous biological effects, including lowering plasma cholesterol and preventing diet-induced hypercholesterolemia. The mechanisms underlying the hypocholesterolemic effect of curcumin are not fully understood. In this regard, intestinal Niemann-Pick C1-like 1 (NPC1L1) cholesterol transporter, the molecular target of intestinal cholesterol absorption inhibitor ezetimibe, plays an essential role in the maintenance of cholesterol homeostasis. The current studies were designed to investigate the effect of curcumin on NPC1L1 function, expression, and promoter activity in intestinal Caco-2 monolayers. NPC1L1 function was evaluated by the measurement of ezetimibe-sensitive [(3)H]cholesterol esterification. Relative abundance of NPC1L1 mRNA and protein was evaluated by real-time PCR and Western blotting, respectively. Luciferase assays were used to measure NPC1L1 promoter activity. Our results showed that curcumin significantly inhibited ezetimibe-sensitive cholesterol esterification in a dose-dependent manner with a maximum decrease (by 52% compared with control) occurring at 50 μM concentration. Curcumin treatment of Caco-2 monolayers also significantly decreased NPC1L1 mRNA and protein expression. Similarly, the promoter activity of the NPC1L1 gene was inhibited significantly (55%) by 50 μM curcumin. The decrease in NPC1L1 promoter activity by curcumin was associated with a reduction in the expression and the DNA-binding activity of the sterol response element-binding protein 2 (SREBP2) transcription factor. Furthermore, the overexpression of active SREBP2 protected NPC1L1 from the inhibitory effect of curcumin. Our studies demonstrate that curcumin directly modulates intestinal NPC1L1 expression via transcriptional regulation and the involvement of SREBP2 transcription factor.
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Affiliation(s)
- Pradeep Kumar
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Pooja Malhotra
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Ke Ma
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Amika Singla
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Omar Hedroug
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Seema Saksena
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Pradeep K. Dudeja
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Ravinder K. Gill
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Waddah A. Alrefai
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
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Kammerer CM, Rainwater DL, Gouin N, Jasti M, Douglas KC, Dressen AS, Ganta P, Vandeberg JL, Samollow PB. Localization of genes for V+LDL plasma cholesterol levels on two diets in the opossum Monodelphis domestica. J Lipid Res 2010; 51:2929-39. [PMID: 20650928 DOI: 10.1194/jlr.m005686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasma cholesterol levels among individuals vary considerably in response to diet. However, the genes that influence this response are largely unknown. Non-HDL (V+LDL) cholesterol levels vary dramatically among gray, short-tailed opossums fed an atherogenic diet, and we previously reported that two quantitative trait loci (QTLs) influenced V+LDL cholesterol on two diets. We used hypothesis-free, genome-wide linkage analyses on data from 325 pedigreed opossums and located one QTL for V+LDL cholesterol on the basal diet on opossum chromosome 1q [logarithm of the odds (LOD) = 3.11, genomic P = 0.019] and another QTL for V+LDL on the atherogenic diet (i.e., high levels of cholesterol and fat) on chromosome 8 (LOD = 9.88, genomic P = 5 x 10(-9)). We then employed a novel strategy involving combined analyses of genomic resources, expression analysis, sequencing, and genotyping to identify candidate genes for the chromosome 8 QTL. A polymorphism in ABCB4 was strongly associated (P = 9 x 10(-14)) with the plasma V+LDL cholesterol concentrations on the high-cholesterol, high-fat diet. The results of this study indicate that genetic variation in ABCB4, or closely linked genes, is responsible for the dramatic differences among opossums in their V+LDL cholesterol response to an atherogenic diet.
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Affiliation(s)
- Candace M Kammerer
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
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Mangat R, Warnakula S, Wang Y, Russell J, Uwiera R, Vine D, Proctor S. Model of intestinal chylomicron over-production and Ezetimibe treatment: Impact on the retention of cholesterol in arterial vessels. ATHEROSCLEROSIS SUPP 2010; 11:17-24. [DOI: 10.1016/j.atherosclerosissup.2010.04.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 04/12/2010] [Accepted: 04/18/2010] [Indexed: 01/28/2023]
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Chan J, Mahaney MC, Kushwaha RS, VandeBerg JF, VandeBerg JL. ABCB4 mediates diet-induced hypercholesterolemia in laboratory opossums. J Lipid Res 2010; 51:2922-8. [PMID: 20488799 DOI: 10.1194/jlr.m005553] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
High-responding opossums are susceptible to developing hypercholesterolemia on a high-cholesterol diet, but low-responding opossums are resistant. The observation of low biliary cholesterol and low biliary phospholipids in high responders suggested that the ABCB4 gene affects response to dietary cholesterol. Two missense mutations (Arg29Gly and Ile235Leu) were found in the ABCB4 gene of high responders. High responders (ATHH strain) were bred with low responders (ATHE or ATHL strain) to produce F1 and F2 progeny in two different genetic crosses (KUSH6 and JCX) to determine the effect of ABCB4 allelic variants on plasma cholesterol concentrations after a dietary challenge. Pedigree-based genetic association analyses consistently implicated a variant in ABCB4 or a closely linked locus as a major, but not the sole, genetic contributor to variation in the plasma cholesterol response to dietary cholesterol. High responders, but not low responders, developed liver injury as indicated by elevated plasma biomarkers of liver function, probably reflecting damage to the canalicular membrane by bile salts because of impaired phospholipid secretion. Our results implicate ABCB4 as a major determinant of diet-induced hypercholesterolemia in high-responding opossums and suggest that other genes interact with ABCB4 to regulate lipemic response to dietary cholesterol.
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Affiliation(s)
- Jeannie Chan
- Southwest National Primate Research Center, Southwest Foundation for Biomedical Research , San Antonio, TX, USA
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Differential expression of intestinal genes in opossums with high and low responses to dietary cholesterol. J Nutr Metab 2009; 2010. [PMID: 20721351 PMCID: PMC2915800 DOI: 10.1155/2010/415075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Accepted: 09/04/2009] [Indexed: 11/18/2022] Open
Abstract
High and low
responding opossums (Monodelphis
domestica) differ in their plasma very
low density lipoprotein and low density
lipoprotein (VLDL+LDL) cholesterol
concentrations when they consume a high
cholesterol diet, which is due in part to
absorption of a higher percentage of dietary
cholesterol in high responders. We compared the
expression of a set of genes that influence
cholesterol absorption in high and low
responders fed a basal or a high cholesterol and
low fat (HCLF) diet. Up-regulation of the
ABCG5, ABCG8,
and IBABP genes by the HCLF
diet in high and low responders may reduce
cholesterol absorption to maintain cholesterol
homeostasis. Differences in expression of the
phospholipase genes (PLA2 and
PLB) and phospholipase activity
were associated with differences in cholesterol
absorption when opossums were fed
cholesterol-enriched diets. Higher
PLA2 and PLB
mRNA levels and higher phospholipase activity
may increase cholesterol absorption in high
responders by enhancing the release of
cholesterol from bile salt micelles for uptake
by intestinal cells.
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