1
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Wang W, Ye J, Xu L, Mo DG, Chen C, Li T, Yao HC. The effects of IGF-1 and IGFBP-2 treatments on the atherosclerosis in the aorta and the coronary arteries of the high cholesterol diet-fed rabbits. Int Immunopharmacol 2024; 127:111409. [PMID: 38118312 DOI: 10.1016/j.intimp.2023.111409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/13/2023] [Accepted: 12/15/2023] [Indexed: 12/22/2023]
Abstract
Several studies have demonstrated suppression of aortic atherosclerosis by insulin like growth factor-1 (IGF-1) in hypercholesterolemic rabbits. Though a recent study has reported that IGF-1 exerts anti-atherogenic effects in coronary arteries, the mechanisms of IGF-1 in coronary arteries need to be further verified. Studies about insulin like growth factor binding protein-2 (IGFBP-2) in atherosclerosis are rarely. The objective of this study is to examine the effects of IGF-1 and IGFBP-2 on the atherosclerosis development in the aorta and coronary arteries of the high-cholesterol diet (HCD)-fed rabbits. New Zealand white rabbits were fed either normal chow (n = 5) or a diet containing 1.0 % cholesterol (n = 18) for 12 weeks. Cholesterol-fed rabbits were given IGF-1 or IGFBP-2 or saline intravenously (each n = 6) for 10 weeks. The results revealed that IGF-1 decreased total cholesterol (TC) and low-density lipoprotein (LDL) levels (p < 0.05), whereas IGFBP-2 did not. IGF-1 significantly attenuated atherosclerotic lesions and reduced accumulated macrophages within the coronary artery plaques, whereas IGFBP-2 deteriorated these changes. Moreover, IGF-1 reduced serum platelet-activating factor acetylhydrolase levels, C reactive protein (CRP), and inhibited the protein expression levels of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). IGFBP-2 elevated serum 8-hydroxy-2'-deoxyguanosine levels, CRP, and promoted the protein expression levels of TNF-α and IL-6. In conclusion, IGF-1 can substantially suppress plaque formation in coronary arteries with a marked inhibition of macrophage accumulation likely via its anti-inflammatory properties, whereas IGFBP-2 plays an opposite effect on atherosclerosis. The present study highlighted a theoretical basis for pharmacological treatment of atherosclerosis.
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Affiliation(s)
- Wei Wang
- Department of Cardiology, Liaocheng People's Hospital Affiliated to Shandong First Medical University, Liaocheng, Shandong 252000, China
| | - Jing Ye
- Department of Pathology, Liaocheng People's Hospital, Liaocheng, Shandong 252000, China
| | - Li Xu
- Stem Cell and Regenerative Medicine Laboratory, Liaocheng People's Hospital, Liaocheng 252000, PR China
| | - De-Gang Mo
- Department of Cardiology, Liaocheng People's Hospital Affiliated to Shandong First Medical University, Liaocheng, Shandong 252000, China
| | - Chen Chen
- Department of Urology, Liaocheng People's Hospital, Liaocheng 252000, PR China
| | - Tai Li
- Department of Nursing, Liaocheng Vocational & Technical College, Liaocheng 252000, China
| | - Heng-Chen Yao
- Department of Cardiology, Liaocheng People's Hospital Affiliated to Shandong First Medical University, Liaocheng, Shandong 252000, China; Department of Cardiology, Liaocheng People's Hospital, Shandong University, Jinan, Shandong 250012, China.
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2
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Yang J, Lee R, Henning SM, Xing E, Huang J, Yang S, Garcia MC, Surampudi V, Heber D, Li Z. Concentrated Grape Powder Consumption Modulates Cholesterol Metabolism and Homeostasis in Healthy Subjects. Mol Nutr Food Res 2023; 67:e2300224. [PMID: 37672802 DOI: 10.1002/mnfr.202300224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
SCOPE Four weeks' of concentrated grape powder (GP) consumption reduces circulating cholesterol in healthy free-living subjects consuming a low-fiber/low-polyphenol diet. Here, the study aims to investigate the underlying mechanisms for cholesterol reduction by evaluating biomarkers of cholesterol de novo biosynthesis, intestinal absorption, miRNA involved in transcriptional regulation of cholesterol metabolism, as well as cholesterol oxidation. METHODS AND RESULTS Fasting plasma samples collected from 19 healthy free-living subjects at baseline and week 4 of GP consumption are used in this study. Gas chromatography-mass (GC-MS) analysis of plasma samples shows that lathosterol, a precursor of cholesterol synthesis, is significantly decreased after GP consumption indicating reduced cholesterol de novo biosynthesis. Markers of intestinal absorption, campesterol, and β-sitosterol are not changed. Realtime PCR shows that plasma exosomal miRNA-1 is increased after GP consumption. GC-MS also shows that GP consumption reduces the plasma cholesterol oxidation product 27-hydroxycholesterol (27-HC). CONCLUSIONS This study enhances the understanding of the mechanisms of the cholesterol lowering effects of GP, and provides new insights into the potential health benefits of grape consumption.
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Affiliation(s)
- Jieping Yang
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Rupo Lee
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Susanne M Henning
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Emily Xing
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Jianjun Huang
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Scarlet Yang
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Michael C Garcia
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Vijaya Surampudi
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - David Heber
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
| | - Zhaoping Li
- Center for Human Nutrition, David Geffen School of Medicine at UCLA, Los Angeles, CA, 1083390095, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, 90073, USA
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3
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Kumbale CM, Zhang Q, Voit EO. Hepatic cholesterol biosynthesis and dioxin-induced dysregulation: A multiscale computational approach. Food Chem Toxicol 2023; 181:114086. [PMID: 37820785 PMCID: PMC10841405 DOI: 10.1016/j.fct.2023.114086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 09/18/2023] [Accepted: 10/03/2023] [Indexed: 10/13/2023]
Abstract
Humans are constantly exposed to lipophilic persistent organic pollutants (POPs) that accumulate in fatty foods. Among the numerous POPs, dioxins, in particular 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), can impact several organ systems. While the hazard is clearly recognized, it is still difficult to develop a comprehensive understanding of the overall health impacts of dioxins. As chemical toxicity testing is steadily adopting new approach methodologies (NAMs), it becomes imperative to develop computational models that can bridge the data gaps between in vitro testing and in vivo outcomes. As an effort to address this challenge, we propose a multiscale computational approach using a "template-and-anchor" (T&A) structure. A template is a high-level umbrella model that permits the integration of information from various, detailed anchor models. In the present study, we use this T&A approach to describe the effect of TCDD on cholesterol dynamics. Specifically, we represent hepatic cholesterol biosynthesis as an anchor model that is perturbed by TCDD, leading to steatosis, along with alterations of plasma cholesterol. In the future, incorporating pertinent information from all anchor models into the template model will allow the characterization of the global effects of dioxin, which can subsequently be translated into overall - and ultimately personalized - human health risk assessment.
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Affiliation(s)
- Carla M Kumbale
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
| | - Eberhard O Voit
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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4
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Lankin VZ, Konovalova GG, Domogatsky SP, Tikhaze AK, Klots IN, Ezhov MV. Clearance and Utilization of Dicarbonyl-Modified LDL in Monkeys and Humans. Int J Mol Sci 2023; 24:10471. [PMID: 37445648 DOI: 10.3390/ijms241310471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 07/15/2023] Open
Abstract
The kinetics of elimination of various dicarbonyl-modified low-density lipoproteins from the bloodstream of Macaca mulatta monkeys were investigated. The low-density lipoproteins (LDL) in the monkey blood plasma were isolated by density gradient ultracentrifugation and labeled in vitro with the fluorescent dye FITC; thereupon, they were modified with different natural low molecular-weight dicarbonyls: malondialdehyde (MDA), glyoxal, or methylglyoxal. The control native FITC-labeled LDL and dicarbonyl-modified FITC-labeled LDL were injected into the monkey's ulnar vein; thereafter, blood samples were taken at fixed time intervals during 24 h. The plasma level of FITC-labeled LDL was determined with spectrofluorimetry. The study established that glyoxal- and monkeysglyoxal-labeled LDL circulated in monkey virtually at the same time as native (non-modified) LDL. In contrast, MDA-modified LDL disappeared from the blood extremely rapidly. Administration of the PCSK9 inhibitor involocumab (which increases LDL utilization) to patients with coronary heart disease (CHD) was found to significantly reduce levels of MDA-modified LDL.
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Affiliation(s)
- Vadim Z Lankin
- Department for Free Radical Biochemistry, E.I. Chazov' National Medical Research Center of Cardiology, Russian Ministry of Health, Moscow 121552, Russia
| | - Galina G Konovalova
- Department for Free Radical Biochemistry, E.I. Chazov' National Medical Research Center of Cardiology, Russian Ministry of Health, Moscow 121552, Russia
| | - Sergey P Domogatsky
- Department for Free Radical Biochemistry, E.I. Chazov' National Medical Research Center of Cardiology, Russian Ministry of Health, Moscow 121552, Russia
| | - Alla K Tikhaze
- Department for Free Radical Biochemistry, E.I. Chazov' National Medical Research Center of Cardiology, Russian Ministry of Health, Moscow 121552, Russia
| | - Igor N Klots
- Research Institute of Medical Primatology, National Research Center "Kurchatov' Institute", Sochi 354376, Russia
| | - Marat V Ezhov
- Laboratory of Lipid Disorders, E.I. Chazov' National Medical Research Center of Cardiology, Russian Ministry of Health, Moscow 121552, Russia
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5
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Liu JT, Doueiry C, Jiang YL, Blaszkiewicz J, Lamprecht MP, Heslop JA, Peterson YK, Carten JD, Traktman P, Yuan Y, Khetani SR, Twal WO, Duncan SA. A human iPSC-derived hepatocyte screen identifies compounds that inhibit production of Apolipoprotein B. Commun Biol 2023; 6:452. [PMID: 37095219 PMCID: PMC10125972 DOI: 10.1038/s42003-023-04739-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 03/21/2023] [Indexed: 04/26/2023] Open
Abstract
Familial hypercholesterolemia (FH) patients suffer from excessively high levels of Low Density Lipoprotein Cholesterol (LDL-C), which can cause severe cardiovascular disease. Statins, bile acid sequestrants, PCSK9 inhibitors, and cholesterol absorption inhibitors are all inefficient at treating FH patients with homozygous LDLR gene mutations (hoFH). Drugs approved for hoFH treatment control lipoprotein production by regulating steady-state Apolipoprotein B (apoB) levels. Unfortunately, these drugs have side effects including accumulation of liver triglycerides, hepatic steatosis, and elevated liver enzyme levels. To identify safer compounds, we used an iPSC-derived hepatocyte platform to screen a structurally representative set of 10,000 small molecules from a proprietary library of 130,000 compounds. The screen revealed molecules that could reduce the secretion of apoB from cultured hepatocytes and from humanized livers in mice. These small molecules are highly effective, do not cause abnormal lipid accumulation, and share a chemical structure that is distinct from any known cholesterol lowering drug.
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Affiliation(s)
- Jui-Tung Liu
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Caren Doueiry
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Yu-Lin Jiang
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Josef Blaszkiewicz
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Mary Paige Lamprecht
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - James A Heslop
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Yuri K Peterson
- Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Juliana Debrito Carten
- Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Paula Traktman
- Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Yang Yuan
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Salman R Khetani
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | | | - Stephen A Duncan
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, 29425, USA.
- Grùthan Biosciences LLC, Hollywood, SC, 29449, USA.
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6
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Coates HW, Capell-Hattam IM, Olzomer EM, Du X, Farrell R, Yang H, Byrne FL, Brown AJ. Hypoxia truncates and constitutively activates the key cholesterol synthesis enzyme squalene monooxygenase. eLife 2023; 12:82843. [PMID: 36655986 PMCID: PMC9851614 DOI: 10.7554/elife.82843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 12/13/2022] [Indexed: 01/20/2023] Open
Abstract
Cholesterol synthesis is both energy- and oxygen-intensive, yet relatively little is known of the regulatory effects of hypoxia on pathway enzymes. We previously showed that the rate-limiting and first oxygen-dependent enzyme of the committed cholesterol synthesis pathway, squalene monooxygenase (SM), can undergo partial proteasomal degradation that renders it constitutively active. Here, we show hypoxia is a physiological trigger for this truncation, which occurs through a two-part mechanism: (1) increased targeting of SM to the proteasome via stabilization of the E3 ubiquitin ligase MARCHF6 and (2) accumulation of the SM substrate, squalene, which impedes the complete degradation of SM and liberates its truncated form. This preserves SM activity and downstream pathway flux during hypoxia. These results uncover a feedforward mechanism that allows SM to accommodate fluctuating substrate levels and may contribute to its widely reported oncogenic properties.
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Affiliation(s)
- Hudson W Coates
- School of Biotechnology and Biomolecular Sciences, UNSW SydneySydneyAustralia
| | | | - Ellen M Olzomer
- School of Biotechnology and Biomolecular Sciences, UNSW SydneySydneyAustralia
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, UNSW SydneySydneyAustralia
| | - Rhonda Farrell
- Prince of Wales Private HospitalRandwickAustralia
- Chris O’Brien LifehouseCamperdownAustralia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, UNSW SydneySydneyAustralia
| | - Frances L Byrne
- School of Biotechnology and Biomolecular Sciences, UNSW SydneySydneyAustralia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW SydneySydneyAustralia
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7
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Stellaard F. From Dietary Cholesterol to Blood Cholesterol, Physiological Lipid Fluxes, and Cholesterol Homeostasis. Nutrients 2022; 14:nu14081643. [PMID: 35458205 PMCID: PMC9025004 DOI: 10.3390/nu14081643] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/04/2022] [Accepted: 04/12/2022] [Indexed: 02/06/2023] Open
Abstract
Dietary cholesterol (C) is a major contributor to the endogenous C pool, and it affects the serum concentration of total C, particularly the low-density lipoprotein cholesterol (LDL-C). A high serum concentration of LDL-C is associated with an increased risk for atherosclerosis and cardiovascular diseases. This concentration is dependent on hepatic C metabolism creating a balance between C input (absorption and synthesis) and C elimination (conversion to bile acids and fecal excretion). The daily C absorption rate is determined by dietary C intake, biliary C secretion, direct trans-intestinal C excretion (TICE), and the fractional C absorption rate. Hepatic C metabolism coordinates C fluxes entering the liver via chylomicron remnants (CMR), LDL, high-density lipoproteins (HDL), hepatic C synthesis, and those leaving the liver via very low-density lipoproteins (VLDL), biliary secretion, and bile acid synthesis. The knowns and the unknowns of this C homeostasis are discussed.
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Affiliation(s)
- Frans Stellaard
- Department of Nutrition and Movement Sciences, NUTRIM (School of Nutrition and Translational Research in Metabolism), Maastricht University Medical Center, P.O. Box 5800 Maastricht, The Netherlands;
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
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8
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Tucker TJ, Embrey MW, Alleyne C, Amin RP, Bass A, Bhatt B, Bianchi E, Branca D, Bueters T, Buist N, Ha SN, Hafey M, He H, Higgins J, Johns DG, Kerekes AD, Koeplinger KA, Kuethe JT, Li N, Murphy B, Orth P, Salowe S, Shahripour A, Tracy R, Wang W, Wu C, Xiong Y, Zokian HJ, Wood HB, Walji A. A Series of Novel, Highly Potent, and Orally Bioavailable Next-Generation Tricyclic Peptide PCSK9 Inhibitors. J Med Chem 2021; 64:16770-16800. [PMID: 34704436 DOI: 10.1021/acs.jmedchem.1c01599] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Proprotein convertase subtilisin-like/kexin type 9 (PCSK9) is a key regulator of plasma LDL-cholesterol (LDL-C) and a clinically validated target for the treatment of hypercholesterolemia and coronary artery disease. Starting from second-generation lead structures such as 2, we were able to refine these structures to obtain extremely potent bi- and tricyclic PCSK9 inhibitor peptides. Optimized molecules such as 44 demonstrated sufficient oral bioavailability to maintain therapeutic levels in rats and cynomolgus monkeys after dosing with an enabled formulation. We demonstrated target engagement and LDL lowering in cynomolgus monkeys essentially identical to those observed with the clinically approved, parenterally dosed antibodies. These molecules represent the first report of highly potent and orally bioavailable macrocyclic peptide PCSK9 inhibitors with overall profiles favorable for potential development as once-daily oral lipid-lowering agents. In this manuscript, we detail the design criteria and multiparameter optimization of this novel series of PCSK9 inhibitors.
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Affiliation(s)
- Thomas J Tucker
- Department of Medicinal Chemistry, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Mark W Embrey
- Department of Medicinal Chemistry, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Candice Alleyne
- Department of Discovery Pharmaceutical Sciences, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Rupesh P Amin
- Department of Safety Assessment and Laboratory Animal Resources, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Alan Bass
- Department of Safety Assessment and Laboratory Animal Resources, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Bhavana Bhatt
- Department of Safety Assessment and Laboratory Animal Resources, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Elisabetta Bianchi
- Peptides and Small Molecule Research and Development Department, IRBM S.p.A., Via Pontina km 30600, 00071 Pomezia (RM), Italy
| | - Danila Branca
- Peptides and Small Molecule Research and Development Department, IRBM S.p.A., Via Pontina km 30600, 00071 Pomezia (RM), Italy
| | - Tjerk Bueters
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Nicole Buist
- Department of Discovery Pharmaceutical Sciences, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Sookhee N Ha
- Department of Modeling and Informatics, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Mike Hafey
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Huaibing He
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - John Higgins
- Department of Discovery Pharmaceutical Sciences, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Douglas G Johns
- Department of Discovery Biology, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Angela D Kerekes
- Department of Medicinal Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Kenneth A Koeplinger
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Jeffrey T Kuethe
- Department of Process Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Nianyu Li
- Department of Safety Assessment and Laboratory Animal Resources, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - BethAnn Murphy
- Department of Discovery Biology, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Peter Orth
- Department of Structural Sciences, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Scott Salowe
- Department of Discovery Biology, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Aurash Shahripour
- Department of Medicinal Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Rodger Tracy
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Weixun Wang
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Chengwei Wu
- Department of Medicinal Chemistry, Merck & Co., Inc., 770 Sumneytown Pike, P.O. Box 4, West Point, Pennsylvania 19486 United States
| | - Yusheng Xiong
- Department of Medicinal Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Hratch J Zokian
- Department of Discovery Biology, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Harold B Wood
- Department of Medicinal Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
| | - Abbas Walji
- Department of Medicinal Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033 United States
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9
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Wang HH, Liu M, Portincasa P, Wang DQH. Recent Advances in the Critical Role of the Sterol Efflux Transporters ABCG5/G8 in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:105-136. [PMID: 32705597 PMCID: PMC8118135 DOI: 10.1007/978-981-15-6082-8_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cardiovascular disease is characterized by lipid accumulation, inflammatory response, cell death, and fibrosis in the arterial wall and is the leading cause of morbidity and mortality worldwide. Cholesterol gallstone disease is caused by complex genetic and environmental factors and is one of the most prevalent and costly digestive diseases in the USA and Europe. Although sitosterolemia is a rare inherited lipid storage disease, its genetic studies led to identification of the sterol efflux transporters ABCG5/G8 that are located on chromosome 2p21 in humans and chromosome 17 in mice. Human and animal studies have clearly demonstrated that ABCG5/G8 play a critical role in regulating hepatic secretion and intestinal absorption of cholesterol and plant sterols. Sitosterolemia is caused by a mutation in either the ABCG5 or the ABCG8 gene alone, but not in both simultaneously. Polymorphisms in the ABCG5/G8 genes are associated with abnormal plasma cholesterol metabolism and may play a key role in the genetic determination of plasma cholesterol concentrations. Moreover, ABCG5/G8 is a new gallstone gene, LITH9. Gallstone-associated variants in ABCG5/G8 are involved in the pathogenesis of cholesterol gallstones in European, Asian, and South American populations. In this chapter, we summarize the latest advances in the critical role of the sterol efflux transporters ABCG5/G8 in regulating hepatic secretion of biliary cholesterol, intestinal absorption of cholesterol and plant sterols, the classical reverse cholesterol transport, and the newly established transintestinal cholesterol excretion, as well as in the pathogenesis and pathophysiology of ABCG5/G8-related metabolic diseases such as sitosterolemia, cardiovascular disease, and cholesterol gallstone disease.
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Affiliation(s)
- Helen H Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Piero Portincasa
- Department of Biomedical Sciences and Human Oncology, Clinica Medica "A. Murri", University of Bari Medical School, Bari, Italy
| | - David Q-H Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY, USA.
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10
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Wu S, Liu Y, Zhu L, Han D, Bello Bodinga M, Yang X. Hepatic metabolomic profiling changes along with postnatal liver maturation in breeder roosters. Biol Open 2018; 7:7/1/bio028944. [PMID: 29358164 PMCID: PMC5829496 DOI: 10.1242/bio.028944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To understand the hepatic metabolic changes during postnatal liver maturation process in breeder roosters, we investigated the hepatic metabolites composition of 1-day-old, 42-day-old, and 35-week-old breeder roosters using gas chromatography-mass spectrometer (GC-MS). Comprehensive multivariate data analyses were applied to identify the distinguishing metabolites of liver. 84 different kinds of distinguishing metabolites were identified between the livers of 1-day-old and 42-day-old breeder roosters, and 58 different kinds of distinguishing metabolites were identified between the livers from 42-day-old and 35-week-old breeder roosters. Further pathway annotations revealed that the hepatic metabolism was extensively remodeled during the postnatal liver maturation process. The antioxidant capacity of the liver and metabolism of carbohydrates, proteins, amino acids, fats, cholesterols, nucleic acids, and vitamins were all significantly changed at different growing periods after birth. Specifically, we found that the hepatic amino acid metabolic function was continuously enhanced from 1-day-old to 35-week-old roosters. However, the glucose and lipid metabolic functions were weakened from 1-day-old to 42-day-old roosters and then elevated from 42-day-old to 35-week-old roosters. In conclusion, the present study revealed that the metabolomic changes are related to the adaption of liver functions in breeder roosters. Summary: This study revealed that hepatic metabolomic changes are related to functional adaption in breeder roosters, which contribute to a better understanding of the hepatic metabolites composition differences during different periods.
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Affiliation(s)
- Shengru Wu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P. R. of China
| | - Yanli Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P. R. of China
| | - Liqin Zhu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P. R. of China
| | - Di Han
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P. R. of China
| | - Musa Bello Bodinga
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P. R. of China
| | - Xiaojun Yang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, P. R. of China
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11
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Wang HH, Garruti G, Liu M, Portincasa P, Wang DQH. Cholesterol and Lipoprotein Metabolism and Atherosclerosis: Recent Advances In reverse Cholesterol Transport. Ann Hepatol 2017; 16:s27-s42. [PMID: 29080338 DOI: 10.5604/01.3001.0010.5495] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 09/18/2017] [Indexed: 02/04/2023]
Abstract
Atherosclerosis is characterized by lipid accumulation, inflammatory response, cell death and fibrosis in the arterial wall, and is major pathological basis for ischemic coronary heart disease (CHD), which is the leading cause of morbidity and mortality in the USA and Europe. Intervention studies with statins have shown to reduce LDL cholesterol levels and subsequently the risk of developing CHD. However, not all the aggressive statin therapy could decrease the risk of developing CHD. Many clinical and epidemiological studies have clearly demonstrated that the HDL cholesterol is inversely associated with risk of CHD and is a critical and independent component of predicting its risk. Elucidations of HDL metabolism give rise to therapeutic targets with potential to raising plasma HDL cholesterol levels, thereby reducing the risk of developing CHD. The concept of reverse cholesterol transport is based on the hypothesis that HDL displays an cardioprotective function, which is a process involved in the removal of excess cholesterol that is accumulated in the peripheral tissues (e.g., macrophages in the aortae) by HDL, transporting it to the liver for excretion into the feces via the bile. In this review, we summarize the latest advances in the role of the lymphatic route in reverse cholesterol transport, as well as the biliary and the non-biliary pathways for removal of cholesterol from the body. These studies will greatly increase the likelihood of discovering new lipid-lowering drugs, which are more effective in the prevention and therapeutic intervention of CHD that is the major cause of human death and disability worldwide.
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Affiliation(s)
- Helen H Wang
- Department of Medicine, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Gabriella Garruti
- Department of Emergency and Organ Transplants, Unit of Endocrinology, University of Bari Medical School, Bari, Italy
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA
| | - Piero Portincasa
- Department of Biomedical Sciences and Human Oncology, Clinica Medica "A. Murri", University of Bari "Aldo Moro" Medical School, Bari, Italy
| | - David Q-H Wang
- Department of Medicine, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
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12
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Shao D, Han J, Hou X, Fry J, Behring JB, Seta F, Long MT, Roy HK, Cohen RA, Matsui R, Bachschmid MM. Glutaredoxin-1 Deficiency Causes Fatty Liver and Dyslipidemia by Inhibiting Sirtuin-1. Antioxid Redox Signal 2017; 27:313-327. [PMID: 27958883 PMCID: PMC5563925 DOI: 10.1089/ars.2016.6716] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS Nonalcoholic fatty liver (NAFL) is a common liver disease associated with metabolic syndrome, obesity, and diabetes that is rising in prevalence worldwide. Various molecular perturbations of key regulators and enzymes in hepatic lipid metabolism cause NAFL. However, redox regulation through glutathione (GSH) adducts in NAFL remains largely elusive. Glutaredoxin-1 (Glrx) is a small thioltransferase that removes protein GSH adducts without having direct antioxidant properties. The liver contains abundant Glrx but its metabolic function is unknown. RESULTS Here we report that normal diet-fed Glrx-deficient mice (Glrx-/-) spontaneously develop obesity, hyperlipidemia, and hepatic steatosis by 8 months of age. Adenoviral Glrx repletion in the liver of Glrx-/- mice corrected lipid metabolism. Glrx-/- mice exhibited decreased sirtuin-1 (SirT1) activity that leads to hyperacetylation and activation of SREBP-1 and upregulation of key hepatic enzymes involved in lipid synthesis. We found that GSH adducts inhibited SirT1 activity in Glrx-/- mice. Hepatic expression of nonoxidizable cysteine mutant SirT1 corrected hepatic lipids in Glrx-/- mice. Wild-type mice fed high-fat diet develop metabolic syndrome, diabetes, and NAFL within several months. Glrx deficiency accelerated high-fat-induced NAFL and progression to steatohepatitis, manifested by hepatic damage and inflammation. INNOVATION These data suggest an essential role of hepatic Glrx in regulating SirT1, which controls protein glutathione adducts in the pathogenesis of hepatic steatosis. CONCLUSION We provide a novel redox-dependent mechanism for regulation of hepatic lipid metabolism, and propose that upregulation of hepatic Glrx may be a beneficial strategy for NAFL. Antioxid. Redox Signal. 27, 313-327.
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Affiliation(s)
- Di Shao
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Jingyan Han
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Xiuyun Hou
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Jessica Fry
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Jessica B Behring
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Francesca Seta
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Michelle T Long
- 3 Division of Gastroenterology, Boston Medical Center , Boston, Massachusetts
| | - Hemant K Roy
- 3 Division of Gastroenterology, Boston Medical Center , Boston, Massachusetts
| | - Richard A Cohen
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts.,2 Cardiovascular Proteomics Center, Boston University School of Medicine , Boston, Massachusetts
| | - Reiko Matsui
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts
| | - Markus M Bachschmid
- 1 Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts.,2 Cardiovascular Proteomics Center, Boston University School of Medicine , Boston, Massachusetts
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13
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Identifying low density lipoprotein cholesterol associated variants in the Annexin A2 (ANXA2) gene. Atherosclerosis 2017; 261:60-68. [PMID: 28456096 PMCID: PMC5446264 DOI: 10.1016/j.atherosclerosis.2017.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/24/2017] [Accepted: 04/12/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND AIMS Annexin-A2 (AnxA2) is an endogenous inhibitor of proprotein convertase subtilisin/kexin type-9 (PCSK9). The repeat-one (R1) domain of AnxA2 binds to PCSK9, blocking its ability to promote degradation of low-density lipoprotein cholesterol-receptors (LDL-R) and thereby regulate low-density lipoprotein cholesterol (LDL-C) levels. Here we identify variants in ANXA2 influencing LDL-C levels and we determine the molecular mechanisms of their effects. RESULTS The ANXA2 single nucleotide polymorphism (SNP) genotype-phenotype association was examined using the Second-Northwick-Park Heart Study (NPHSII) (n∼2700) and the UCL-LSHTM-Edinburgh-Bristol (UCLEB) consortium (n∼14,600). The ANXA2-R1 domain coding-SNP rs17845226 (V98L) associated with LDL-C, homozygotes for the minor allele having ≈18.8% higher levels of LDL-C (p = 0.004), and higher risk of coronary heart disease (CHD) (p = 0.04). The SNP is in modest linkage disequilibrium (r2 > 0.5) with two intergenic SNPs, rs17191344 and rs11633032. Both SNPs showed allele-specific protein binding, and the minor alleles caused significant reduction in reporter gene expression (≈18%, p < 0.001). In the expression quantitative trait loci (eQTL) study, minor allele homozygotes have significantly lower levels of ANXA2-mRNA expression (p = 1.36 × 10-05). CONCLUSIONS Both rs11633032 and rs17191344 SNPs are functional variants, where the minor alleles create repressor-binding protein sites for transcription factors that contribute to reduced ANXA2 gene expression. Lower AnxA2 levels could increase plasma levels of PCSK9 and thus increase LDL-C levels and risk of CHD. This supports, for the first time in humans, previous observations in mouse models that changes in the levels of AnxA2 directly influence plasma LDL-C levels, and thus implicate this protein as a potential therapeutic target for LDL-C lowering.
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14
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The Interpretation of Cholesterol Balance Derived Synthesis Data and Surrogate Noncholesterol Plasma Markers for Cholesterol Synthesis under Lipid Lowering Therapies. CHOLESTEROL 2017; 2017:5046294. [PMID: 28321334 PMCID: PMC5340945 DOI: 10.1155/2017/5046294] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/21/2016] [Accepted: 01/26/2017] [Indexed: 12/12/2022]
Abstract
The cholesterol balance procedure allows the calculation of cholesterol synthesis based on the assumption that loss of endogenous cholesterol via fecal excretion and bile acid synthesis is compensated by de novo synthesis. Under ezetimibe therapy hepatic cholesterol is diminished which can be compensated by hepatic de novo synthesis and hepatic extraction of plasma cholesterol. The plasma lathosterol concentration corrected for total cholesterol concentration (R_Lath) as a marker of de novo cholesterol synthesis is increased during ezetimibe treatment but unchanged under treatment with ezetimibe and simvastatin. Cholesterol balance derived synthesis data increase during both therapies. We hypothesize the following. (1) The cholesterol balance data must be applied to the hepatobiliary cholesterol pool. (2) The calculated cholesterol synthesis value is the sum of hepatic de novo synthesis and the net plasma-liver cholesterol exchange rate. (3) The reduced rate of biliary cholesterol absorption is the major trigger for the regulation of hepatic cholesterol metabolism under ezetimibe treatment. Supportive experimental and literature data are presented that describe changes of cholesterol fluxes under ezetimibe, statin, and combined treatments in omnivores and vegans, link plasma R_Lath to liver function, and define hepatic de novo synthesis as target for regulation of synthesis. An ezetimibe dependent direct hepatic drug effect cannot be excluded.
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15
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16
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Gibbs JP, Doshi S, Kuchimanchi M, Grover A, Emery MG, Dodds MG, Gibbs MA, Somaratne R, Wasserman SM, Blom D. Impact of Target-Mediated Elimination on the Dose and Regimen of Evolocumab, a Human Monoclonal Antibody Against Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9). J Clin Pharmacol 2016; 57:616-626. [PMID: 27861991 PMCID: PMC5412926 DOI: 10.1002/jcph.840] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/11/2016] [Indexed: 01/14/2023]
Abstract
Understanding the pharmacokinetic (PK) and pharmacodynamic (PD) relationship of a therapeutic monoclonal antibody against proprotein convertase subtilisin/kexin type 9 (PCSK9) exhibiting target-mediated drug disposition (TMDD) is critical for selecting optimal dosing regimens. We describe the PK/PD relationship of evolocumab using a mathematical model that captures evolocumab binding and removal of unbound PCSK9 as well as reduction in circulating low-density lipoprotein cholesterol (LDL-C). Data were pooled from 2 clinical studies: a single-dose escalation study in healthy subjects (7-420 mg SC; n = 44) and a multiple-dose escalation study in statin-treated hypercholesterolemic patients (14 mg weekly to 420 mg monthly [QM] SC; n = 57). A TMDD model described the time course of unbound evolocumab concentrations and removal of unbound PCSK9. The estimated linear clearance and volume of evolocumab were 0.256 L/day and 2.66 L, respectively, consistent with other monoclonal antibodies. The time course of LDL-C reduction was described by an indirect response model with the elimination rate of LDL-C being modulated by unbound PCSK9. The concentration of unbound PCSK9 associated with half-maximal inhibition (IC50 ) of LDL-C elimination was 1.46 nM. Based on simulations, 140 mg every 2 weeks (Q2W) and 420 mg QM were predicted to achieve a similar time-averaged effect of 69% reduction in LDL-C in patients on statin therapy, suggesting that an approximate 3-fold dose increase is required for a 2-fold extension in the dosing interval. Evolocumab dosing regimens of 140 mg Q2W or 420 mg QM were predicted to result in comparable reductions in LDL-C over a monthly period, consistent with results from recently completed phase 3 studies.
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Affiliation(s)
- John P Gibbs
- Amgen Inc, Thousand Oaks, CA, USA.,Current affiliation: AbbVie, North Chicago, IL, USA
| | | | | | - Anita Grover
- Amgen Inc, Thousand Oaks, CA, USA.,Current affiliation: BioMarin Pharmaceuticals, Novato, CA, USA
| | | | - Michael G Dodds
- Amgen Inc, Thousand Oaks, CA, USA.,Current affiliation: Quantitative Solutions, a Certara Company, Seattle, WA, USA
| | - Megan A Gibbs
- Amgen Inc, Thousand Oaks, CA, USA.,Current affiliation: BioMarin Pharmaceuticals, Novato, CA, USA
| | | | | | - Dirk Blom
- Division of Lipidology, Department of Medicine, University of Cape Town, Cape Town, South Africa
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17
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Different Susceptibilities between Apoe- and Ldlr-Deficient Mice to Inflammation-Associated Colorectal Carcinogenesis. Int J Mol Sci 2016; 17:ijms17111806. [PMID: 27801847 PMCID: PMC5133807 DOI: 10.3390/ijms17111806] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/21/2016] [Accepted: 10/19/2016] [Indexed: 12/17/2022] Open
Abstract
Hypercholesterolemia resulting in atherosclerosis is associated with an increased risk of ischemic heart disease and colorectal cancer (CRC). However, the roles of apoliprotein (Apo) E (Apoe) and low-density lipoprotein (Ldl) receptor (Ldlr) in colorectal carcinogenesis have not yet been investigated. In this study, we examined the susceptibility of Apoe-deficient and Ldlr-deficient mice, which are genetic animal models of atherosclerosis to azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colorectal carcinogenesis. In Experiment 1, male Apoe-deficient (n = 20) and wild type (WT) mice (C57BL/6J, n = 21) were treated with a single intraperitoneal (i.p.) injection of AOM (10 mg/kg body weight) and then given 1.5% DSS in drinking water for seven days. They were maintained up to week 20 and sacrificed for the histopathological examination of colorectal tumors. The mRNA expression of cyclooxygenase (Cox)-2, inducible nitric oxide synthase (Nos2), tumor necrosis factor (Tnf)-α interleukin (Il)-1β, and Il-6 was assayed in the colorectal mucosa. In Experiment 2, male Ldlr-deficient (n = 14) and WT mice (C57BL/6J, n = 10) were given a single i.p. injection of AOM (10 mg/kg body weight) and then given 2% DSS in drinking water for seven days. They were sacrificed at week 20 to evaluate their colorectum histopathologically. In Experiment 1, the multiplicity of CRCs was significantly higher in the Apoe-deficient mice (2.75 ± 1.48) than in the WT mice (0.62 ± 0.67). The serum lipoprotein levels in the Apoe-deficient mice were also significantly higher than in the WT mice. In Experiment 2, the incidence (29%) and multiplicity (0.50 ± 0.94) of CRCs in the Ldlr mice were significantly lower than in the WT mice (80% incidence and 3.10 ± 2.38 multiplicity). The mRNA expression of two inducible enzymes and certain pro-inflammatory cytokines in the colorectum of each genotype was greater than in the respective WT mice. The values in the Apoe-deficient mice were much greater than in the Ldlr mice. These findings suggest that Apoe-deficient mice showed increased susceptibility to inflammation-associated colorectal carcinogenesis due to their high reactivity to inflammatory stimuli.
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18
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Kirchgessner TG, Sleph P, Ostrowski J, Lupisella J, Ryan CS, Liu X, Fernando G, Grimm D, Shipkova P, Zhang R, Garcia R, Zhu J, He A, Malone H, Martin R, Behnia K, Wang Z, Barrett YC, Garmise RJ, Yuan L, Zhang J, Gandhi MD, Wastall P, Li T, Du S, Salvador L, Mohan R, Cantor GH, Kick E, Lee J, Frost RJA. Beneficial and Adverse Effects of an LXR Agonist on Human Lipid and Lipoprotein Metabolism and Circulating Neutrophils. Cell Metab 2016; 24:223-33. [PMID: 27508871 DOI: 10.1016/j.cmet.2016.07.016] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/21/2016] [Accepted: 07/21/2016] [Indexed: 01/20/2023]
Abstract
The development of LXR agonists for the treatment of coronary artery disease has been challenged by undesirable properties in animal models. Here we show the effects of an LXR agonist on lipid and lipoprotein metabolism and neutrophils in human subjects. BMS-852927, a novel LXRβ-selective compound, had favorable profiles in animal models with a wide therapeutic index in cynomolgus monkeys and mice. In healthy subjects and hypercholesterolemic patients, reverse cholesterol transport pathways were induced similarly to that in animal models. However, increased plasma and hepatic TG, plasma LDL-C, apoB, apoE, and CETP and decreased circulating neutrophils were also evident. Furthermore, similar increases in LDL-C were observed in normocholesterolemic subjects and statin-treated patients. The primate model markedly underestimated human lipogenic responses and did not predict human neutrophil effects. These studies demonstrate both beneficial and adverse LXR agonist clinical responses and emphasize the importance of further translational research in this area.
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Affiliation(s)
| | - Paul Sleph
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Jacek Ostrowski
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - John Lupisella
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Carol S Ryan
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Xiaoqin Liu
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Gayani Fernando
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Denise Grimm
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Petia Shipkova
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Rongan Zhang
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Ricardo Garcia
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Jun Zhu
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Aiqing He
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Harold Malone
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | | | - Kamelia Behnia
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Zhaoqing Wang
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Yu Chen Barrett
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Robert J Garmise
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Long Yuan
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Jane Zhang
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Mohit D Gandhi
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Philip Wastall
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Tong Li
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Shuyan Du
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Lisa Salvador
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Raju Mohan
- Exelixis, Inc., South San Francisco, CA 94080, USA
| | - Glenn H Cantor
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Ellen Kick
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - John Lee
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Robert J A Frost
- Research and Development, Bristol-Myers Squibb, Princeton, NJ 08543, USA
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Karami A, Goh YM, Jahromi MF, Lazorchak JM, Abdullah M, Courtenay SC. Diploid and triploid African catfish (Clarias gariepinus) differ in biomarker responses to the pesticide chlorpyrifos. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 557-558:204-211. [PMID: 26994807 DOI: 10.1016/j.scitotenv.2016.03.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/28/2016] [Accepted: 03/05/2016] [Indexed: 06/05/2023]
Abstract
The impacts of environmental stressors on polyploid organisms are largely unknown. This study investigated changes in morphometric, molecular, and biochemical parameters in full-sibling diploid and triploid African catfish (Clarias gariepinus) in response to chlorpyrifos (CPF) exposures. Juvenile fish were exposed to three concentrations of CPF (mean measured μg/L (SD): 9.71 (2.27), 15.7 (3.69), 31.21 (5.04)) under a static-renewal condition for 21days. Diploid control groups had higher hepatosomatic index (HSI), plasma testosterone (T), and brain GnRH and cyp19a2 expression levels than triploids. In CPF-exposed groups, changes in HSI, total weight and length were different between the diploid and triploid fish. In contrast, condition factor did not alter in any of the treatments, while visceral-somatic index (VSI) changed only in diploids. In diploid fish, exposure to CPF did not change brain 11β-hsd2, ftz-f1, foxl2, GnRH or cyp19a2 mRNA levels, while reduced tph2 transcript levels compared to the control group. In contrast, 11β-hsd2 and foxl2 expression levels were changed in triploids following CPF exposures. In diploids, plasma T levels showed a linear dose-response reduction across CPF treatments correlating with liver weight and plasma total cholesterol concentrations. In contrast, no changes in plasma cholesterol and T concentrations were observed in triploids. Plasma cortisol and 17-β estradiol (E2) showed no response to CPF exposure in either ploidy. Results of this first comparison of biomarker responses to pesticide exposure in diploid and polyploid animals showed substantial differences between diploid and triploid C. gariepinus.
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Affiliation(s)
- Ali Karami
- Laboratory of Aquatic Toxicology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Selangor, Malaysia.
| | - Yong-Meng Goh
- Department of Veterinary Preclinical Sciences, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Selangor, Malaysia
| | - Mohammad Faseleh Jahromi
- Laboratory of Animal Production, Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 Selangor, Malaysia
| | - James M Lazorchak
- Office of Research and Development, National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH, United States
| | - Maha Abdullah
- Laboratory of Immunology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Selangor, Malaysia
| | - Simon C Courtenay
- School of Environment, Resources and Sustainability, Canadian Water Network, Canadian Rivers Institute, University of Waterloo, Canada
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20
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Khanal P, Johnsen L, Axel AMD, Hansen PW, Kongsted AH, Lyckegaard NB, Nielsen MO. Long-Term Impacts of Foetal Malnutrition Followed by Early Postnatal Obesity on Fat Distribution Pattern and Metabolic Adaptability in Adult Sheep. PLoS One 2016; 11:e0156700. [PMID: 27257993 PMCID: PMC4892656 DOI: 10.1371/journal.pone.0156700] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 05/18/2016] [Indexed: 11/27/2022] Open
Abstract
We aimed to investigate whether over- versus undernutrition in late foetal life combined with obesity development in early postnatal life have differential implications for fat distribution and metabolic adaptability in adulthood. Twin-pregnant ewes were fed NORM (100% of daily energy and protein requirements), LOW (50% of NORM) or HIGH (150%/110% of energy/protein requirements) diets during the last trimester. Postnatally, twin-lambs received obesogenic (HCHF) or moderate (CONV) diets until 6 months of age, and a moderate (obesity correcting) diet thereafter. At 2½ years of age (adulthood), plasma metabolite profiles during fasting, glucose, insulin and propionate (in fed and fasted states) tolerance tests were examined. Organ weights were determined at autopsy. Early obesity development was associated with lack of expansion of perirenal, but not other adipose tissues from adolescence to adulthood, resulting in 10% unit increased proportion of mesenteric of intra-abdominal fat. Prenatal undernutrition had a similar but much less pronounced effect. Across tolerance tests, LOW-HCHF sheep had highest plasma levels of cholesterol, urea-nitrogen, creatinine, and lactate. Sex specific differences were observed, particularly with respect to fat deposition, but direction of responses to early nutrition impacts were similar. However, prenatal undernutrition induced greater metabolic alterations in adult females than males. Foetal undernutrition, but not overnutrition, predisposed for adult hypercholesterolaemia, hyperureaemia, hypercreatinaemia and hyperlactataemia, which became manifested only in combination with early obesity development. Perirenal expandability may play a special role in this context. Differential nutrition recommendations may be advisable for individuals with low versus high birth weights.
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Affiliation(s)
- Prabhat Khanal
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Lærke Johnsen
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Anne Marie Dixen Axel
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Pernille Willert Hansen
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Anna Hauntoft Kongsted
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Nette Brinch Lyckegaard
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Mette Olaf Nielsen
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
- * E-mail:
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Kim H, Kim DH, Seo KH, Chon JW, Nah SY, Bartley GE, Arvik T, Lipson R, Yokoyama W. Modulation of the intestinal microbiota is associated with lower plasma cholesterol and weight gain in hamsters fed chardonnay grape seed flour. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:1460-1467. [PMID: 25598538 DOI: 10.1021/jf5026373] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The relationship between the intestinal microbiota and the hypocholesterolemic and antiobesity effects of whole grape seed flour from white and red winemaking was evaluated. Male Golden Syrian hamsters were fed a high-fat (HF) control diet or a HF diet supplemented with 10% partially defatted grape seed flours from either Chardonnay (ChrSd) or Cabernet Sauvignon (CabSd) grapes for 3 weeks. The numbers of total bacteria and relative abundances of Bifidobacterium spp., Lactobacillus spp., and Firmicutes in feces were significantly lower, while the relative abundance of Bacteroides fragilis was greater than the control from feeding the ChrSd diet. The ratio of Firmicutes/Bacteroidetes (F/B) was lower in the ChrSd diet. There were significantly positive correlations between Lactobacillus spp., ratio of F/B, and plasma total- and LDL-cholesterol and liver weight. The reduction of Lactobacillus spp. by the ChrSd diet was accompanied by inhibition of Farnesoid X receptor (FXR) signaling in the intestine as expression of intestinal fibrablast growth factor (FGF)15, positively regulated by FXR, was decreased. Expression of CYP7A1, negatively regulated by FGF15, was up-regulated in the liver, which indicates that alteration of the intestinal microbiota may regulate bile acid and lipid metabolism. These findings suggest that beneficial health effects of Chardonnay grape seed flour on HF-induced metabolic disease relate in part to modulation of intestinal microbiota and their metabolic processes.
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Affiliation(s)
- Hyunsook Kim
- Department of Nutrition, UC Davis , Davis, California 95616, United States
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22
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Kirchgessner TG, Martin R, Sleph P, Grimm D, Liu X, Lupisella J, Smalley J, Narayanan R, Xie Y, Ostrowski J, Cantor GH, Mohan R, Kick E. Pharmacological characterization of a novel liver X receptor agonist with partial LXRα activity and a favorable window in nonhuman primates. J Pharmacol Exp Ther 2014; 352:305-14. [PMID: 25467132 DOI: 10.1124/jpet.114.219923] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Liver X Receptors (LXRs) α and β are nuclear hormone receptors that regulate multiple genes involved in reverse cholesterol transport (RCT) and are potential drug targets for atherosclerosis. However, full pan agonists also activate lipogenic genes, resulting in elevated plasma and hepatic lipids. We report the pharmacology of BMS-779788 [2-(2-(1-(2-chlorophenyl)-1-methylethyl)-1-(3'-(methylsulfonyl)-4-biphenylyl)-1H-imidazol-4-yl)-2-propanol], a potent partial LXR agonist with LXRβ selectivity, which has an improved therapeutic window in the cynomolgus monkey compared with a full pan agonist. BMS-779788 induced LXR target genes in blood in vivo with an EC50 = 610 nM, a value similar to its in vitro blood gene induction potency. BMS-779788 was 29- and 12-fold less potent than the full agonist T0901317 in elevating plasma triglyceride and LDL cholesterol, respectively, with similar results for plasma cholesteryl ester transfer protein and apolipoprotein B. However, ABCA1 and ABCG1 mRNA inductions in blood, which are critical for RCT, were comparable. Increased liver triglyceride was observed after 7-day treatment with BMS-779788 at the highest dose tested and was nearly identical to the dose response for plasma triglyceride, consistent with the central role of liver LXR in these lipogenic effects. Dose-dependent increases in biliary cholesterol and decreases in phospholipid and bile acid occurred in BMS-779788-treated animals, similar to LXR agonist effects reported in mouse. In summary, BMS-779788, a partial LXRβ selective agonist, has decreased lipogenic potential compared with a full pan agonist in cynomolgus monkeys, with similar potency in the induction of genes known to stimulate RCT. This provides support in nonhuman primates for improving LXR agonist therapeutic windows by limiting LXRα activity.
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Affiliation(s)
- Todd G Kirchgessner
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Richard Martin
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Paul Sleph
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Denise Grimm
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Xiaoqin Liu
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - John Lupisella
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - James Smalley
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Rangaraj Narayanan
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Yinong Xie
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Jacek Ostrowski
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Glenn H Cantor
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Raju Mohan
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
| | - Ellen Kick
- Bristol-Myers Squibb Research and Development, Bristol-Myers Squibb, Inc., Princeton, New Jersey (T.G.K., P.S., D.G., X.L., J.L., J.S., R.N., J.O., G.H.C., E.K.); and Exelixis, Inc., South San Francisco, California (R.Ma., Y.X., R.Mo.)
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Hidden disease susceptibility and sexual dimorphism in the heterozygous knockout of Cyp51 from cholesterol synthesis. PLoS One 2014; 9:e112787. [PMID: 25393872 PMCID: PMC4231084 DOI: 10.1371/journal.pone.0112787] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/15/2014] [Indexed: 01/16/2023] Open
Abstract
We examined the genotype-phenotype interactions of Cyp51+/- mice carrying one functional allele of lanosterol 14α-demethylase from cholesterol biosynthesis. No distinct developmental or morphological abnormalities were observed by routine visual inspection of Cyp51+/- and Cyp51+/+ mice and fertility was similar. We further collected a large data-set from female and male Cyp51+/- mice and controls fed for 16 weeks with three diets and applied linear regression modeling. We used 3 predictor variables (genotype, sex, diet), and 39 response variables corresponding to the organ characteristics (7), plasma parameters (7), and hepatic gene expression (25). We observed significant differences between Cyp51+/- and wild-type mice in organ characteristics and blood lipid profile. Hepatomegaly was observed in Cyp51+/- males, together with elevated total and low-density lipoprotein cholesterol. Cyp51+/- females fed high-fat, high-cholesterol diet were leaner and had elevated plasma corticosterone compared to controls. We observed elevated hepatocyte apoptosis, mitosis and lipid infiltration in heterozygous knockouts of both sexes. The Cyp51+/- females had a modified lipid storage homeostasis protecting them from weight-gain when fed high-fat high-cholesterol diet. Malfunction of one Cyp51 allele therefore initiates disease pathways towards cholesterol-linked liver pathologies and sex-dependent response to dietary challenge.
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Zanotti I, Dall'Asta M, Mena P, Mele L, Bruni R, Ray S, Del Rio D. Atheroprotective effects of (poly)phenols: a focus on cell cholesterol metabolism. Food Funct 2014; 6:13-31. [PMID: 25367393 DOI: 10.1039/c4fo00670d] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Collated observations from several epidemiological studies have demonstrated that dietary intake of (poly)phenols from nuts, coffee, cocoa, grapes, and berries may protect against the development of atherosclerosis. Whereas this beneficial activity has previously been linked mainly to antioxidant or anti-inflammatory properties, recently emerging data suggest mechanisms by which (poly)phenolic substances can modulate cellular lipid metabolism, thereby mitigating atherosclerotic plaque formation. In this review, both experimental studies and clinical trials investigating the atheroprotective effects of the most relevant dietary (poly)phenols are critically discussed.
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Affiliation(s)
- Ilaria Zanotti
- Department of Pharmacy, University of Parma, Viale delle Scienze 27/A, 43124 Parma, Italy
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25
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Cholesterol in the retina: the best is yet to come. Prog Retin Eye Res 2014; 41:64-89. [PMID: 24704580 DOI: 10.1016/j.preteyeres.2014.03.002] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/13/2014] [Accepted: 03/17/2014] [Indexed: 01/09/2023]
Abstract
Historically understudied, cholesterol in the retina is receiving more attention now because of genetic studies showing that several cholesterol-related genes are risk factors for age-related macular degeneration (AMD) and because of eye pathology studies showing high cholesterol content of drusen, aging Bruch's membrane, and newly found subretinal lesions. The challenge before us is determining how the cholesterol-AMD link is realized. Meeting this challenge will require an excellent understanding these genes' roles in retinal physiology and how chorioretinal cholesterol is maintained. In the first half of this review, we will succinctly summarize physico-chemical properties of cholesterol, its distribution in the human body, general principles of maintenance and metabolism, and differences in cholesterol handling in human and mouse that impact on experimental approaches. This information will provide a backdrop to the second part of the review focusing on unique aspects of chorioretinal cholesterol homeostasis, aging in Bruch's membrane, cholesterol in AMD lesions, a model for lesion biogenesis, a model for macular vulnerability based on vascular biology, and alignment of AMD-related genes and pathobiology using cholesterol and an atherosclerosis-like progression as unifying features. We conclude with recommendations for the most important research steps we can take towards delineating the cholesterol-AMD link.
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Kim H, Bartley GE, Arvik T, Lipson R, Nah SY, Seo K, Yokoyama W. Dietary supplementation of chardonnay grape seed flour reduces plasma cholesterol concentration, hepatic steatosis, and abdominal fat content in high-fat diet-induced obese hamsters. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:1919-1925. [PMID: 24517872 DOI: 10.1021/jf404832s] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The mechanisms for the hypocholesterolemic and antiobesity effects of grape seed flours derived from white and red winemaking processing were investigated using male Golden Syrian hamsters fed high-fat (HF) diets supplemented with 10% partially defatted grape seed flours from Chardonnay (ChrSd), Cabernet Sauvignon (CabSd), or Syrah (SyrSd) pomace as compared to a HF control diet for 3 weeks. Hamsters fed the ChrSd diet had significantly lowered plasma total-, VLDL-, and LDL-cholesterol concentrations compared to the CabSd, SyrSd, and control diets. The improved plasma cholesterol after ChrSd was correlated with the up-regulation of hepatic genes related to cholesterol (CYP51) and bile acid (CYP7A1) synthesis as well as LDL-cholesterol uptake (LDLR). A reduction of hepatic lipid content was associated with altered expression of the genes related to lipid metabolism. However, fecal total lipid content was not changed. Expression of ileal apical sodium bile acid transporter (ASBT) was not affected by ChrSd, indicating unchanged ileal bile acid reabsorption. The antiobesity effect of the ChrSd diet appears to be related to expression of adipogenesis- and inflammation-related genes in adipose tissue. These findings suggest that flavonoid-rich Chardonnay grape seed flour induced cholesterol-lowering, antiobesity, and anti-inflammatory health benefits and attenuation of hepatic steatosis via regulation of gene expression related to cholesterol, bile acid, and lipid metabolism in liver and adipose tissue.
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Affiliation(s)
- Hyunsook Kim
- Department of Nutrition, University of California, Davis, California 95616, United States
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27
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Cross-talk between liver and intestine in control of cholesterol and energy homeostasis. Mol Aspects Med 2014; 37:77-88. [PMID: 24560594 DOI: 10.1016/j.mam.2014.02.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 12/04/2013] [Accepted: 02/10/2014] [Indexed: 12/19/2022]
Abstract
A major hurdle for organisms to dispose of cholesterol is the inability to degrade the sterol nucleus which constitutes the central part of the molecule. Synthesis of the sterol nucleus requires a complex, energy costly, metabolic pathway but also generates a diverse array of intermediates serving crucial roles in cellular energy metabolism and signal transduction. This may be the reason why this complex pathway has survived evolutionary pressure. The only way to get rid of substantial amounts of cholesterol is conversion into bile acid or direct excretion of the sterol in the feces. The lack of versatility in disposal mechanisms causes a lack of flexibility to regulate cholesterol homeostasis which may underlie the considerable human pathology linked to cholesterol removal from the body. Export of cholesterol from the body requires an intricate communication between intestine and the liver. The last decade this inter-organ cross talk has been focus of intense research leading to considerable new insight. This novel information on particular the cross-talk between liver and intestine and role of bile acids as signal transducing molecules forms the focus of this review.
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28
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Chuang JC, Valasek MA, Lopez AM, Posey KS, Repa JJ, Turley SD. Sustained and selective suppression of intestinal cholesterol synthesis by Ro 48-8071, an inhibitor of 2,3-oxidosqualene:lanosterol cyclase, in the BALB/c mouse. Biochem Pharmacol 2014; 88:351-63. [PMID: 24486573 DOI: 10.1016/j.bcp.2014.01.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/17/2014] [Accepted: 01/21/2014] [Indexed: 01/11/2023]
Abstract
The small intestine plays a fundamentally important role in regulating whole body cholesterol balance and plasma lipoprotein composition. This is articulated through the interplay of a constellation of genes that ultimately determines the net amount of chylomicron cholesterol delivered to the liver. Major advances in our insights into regulation of the cholesterol absorption pathway have been made using genetically manipulated mouse models and agents such as ezetimibe. One unresolved question is how a sustained pharmacological inhibition of intestinal cholesterol synthesis in vivo may affect cholesterol handling by the absorptive cells. Here we show that the lanosterol cyclase inhibitor, Ro 48-8071, when fed to BALB/c mice in a chow diet (20 mg/day/kg body weight), leads to a rapid and sustained inhibition (>50%) of cholesterol synthesis in the whole small intestine. Sterol synthesis was also reduced in the large intestine and stomach. In contrast, hepatic cholesterol synthesis, while markedly suppressed initially, rebounded to higher than baseline rates within 7 days. Whole body cholesterol synthesis, fractional cholesterol absorption, and fecal neutral and acidic sterol excretion were not consistently changed with Ro 48-8071 treatment. There were no discernible effects of this agent on intestinal histology as determined by H&E staining and the level of Ki67, an index of proliferation. The mRNA expression for multiple genes involved in intestinal cholesterol regulation including NPC1L1 was mostly unchanged although there was a marked rise in the mRNA level for the PXR target genes CYP3A11 and CES2A.
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Affiliation(s)
- Jen-Chieh Chuang
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Mark A Valasek
- Pathology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Adam M Lopez
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Kenneth S Posey
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Joyce J Repa
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States; Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
| | - Stephen D Turley
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, United States.
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Cortes VA, Busso D, Mardones P, Maiz A, Arteaga A, Nervi F, Rigotti A. Retracted: Advances in the physiological and pathological implications of cholesterol. Biol Rev Camb Philos Soc 2013; 88:825-43. [DOI: 10.1111/brv.12025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 01/22/2013] [Accepted: 01/25/2013] [Indexed: 01/07/2023]
Affiliation(s)
- Victor A. Cortes
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Dolores Busso
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Pablo Mardones
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Alberto Maiz
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Antonio Arteaga
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Flavio Nervi
- Department of Gastroenterology; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Santiago Chile
| | - Attilio Rigotti
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
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30
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Cong R, Jia Y, Li R, Ni Y, Yang X, Sun Q, Parvizi N, Zhao R. Maternal low-protein diet causes epigenetic deregulation of HMGCR and CYP7α1 in the liver of weaning piglets. J Nutr Biochem 2012; 23:1647-54. [DOI: 10.1016/j.jnutbio.2011.11.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/18/2011] [Accepted: 11/22/2011] [Indexed: 12/30/2022]
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Distribution of perfluorooctanesulfonate and perfluorooctanoate into human plasma lipoprotein fractions. Toxicol Lett 2012; 210:360-5. [PMID: 22387339 DOI: 10.1016/j.toxlet.2012.02.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 02/13/2012] [Accepted: 02/15/2012] [Indexed: 01/09/2023]
Abstract
Some cross-sectional epidemiological studies have reported positive associations of serum concentrations of non-high density lipoprotein cholesterol with serum perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA). However, the strength of the reported associations is inconsistent for exposure-response across three orders of magnitude of serum PFOS and/or PFOA concentrations. These positive associations are unexpected based on toxicological/mechanistic studies, suggesting that the associations may have a biological, rather than a causal, basis. This study tested the hypothesis that PFOS and PFOA distribute into serum lipoprotein fractions such that increases in serum lipoproteins would result in corresponding increases in serum concentrations of PFOS and PFOA. Based on observed binding of PFOS and PFOA to isolated β-lipoproteins in physiological saline (96% and 40% bound, respectively) in preliminary experiments using ultrafiltration and LC-MS/MS methods, binding to human donor plasma lipoprotein fractions was investigated by two density gradient methods. The majority of PFOS and PFOA recovered masses were found in lipoprotein-depleted plasma. Plasma density gradient fractionation data suggested that maximally 9% of PFOS distributes to lipoprotein-containing fractions, yet only 1% or less of PFOA is so distributed. These data do not support a strong role for plasma lipoprotein fractions in explaining the inconsistent dose-response associations reported in cross-sectional epidemiological studies.
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Mubiru JN, Garcia-Forey M, Higgins PB, Hemmat P, Cavazos NE, Dick EJ, Owston MA, Bauer CA, Shade RE, Comuzzie AG, Rogers J. A preliminary report on the feeding of cynomolgus monkeys (Macaca fascicularis) with a high-sugar high-fat diet for 33 weeks. J Med Primatol 2011; 40:335-41. [PMID: 21812784 DOI: 10.1111/j.1600-0684.2011.00495.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND The metabolic syndrome is common in populations exposed to a typical Western diet. There is a lack of an animal model that mimics this condition. METHODS We fed 15 cynomolgus monkeys ad libitum a high-sugar high-fat (HSHF) diet for 33 weeks. Body weight, body composition, serum lipids, and insulin were measured at baseline and at 33 weeks. RESULTS The animals tolerated the HSHF diet very well. In the intervention group, total serum cholesterol and low-density lipoprotein cholesterol were 3- and 5-fold higher, respectively, at 33 weeks as compared with their baseline levels. Serum high-density lipoprotein cholesterol and triglycerides were not significantly affected. Dual-energy X-ray absorptiometry (DXA) analysis of the intervention group indicated that the trunk fat mass increased by 187% during this period. CONCLUSIONS Cynomolgus monkeys should be a useful model for investigating the interactions of diet and other factors such as genetics in the development of the metabolic syndrome.
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Affiliation(s)
- James N Mubiru
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA.
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Kim H, Turowski M, Anderson WHK, Young SA, Kim Y, Yokoyama W. Supplementation of hydroxypropyl methylcellulose into yeast leavened all-whole grain barley bread potentiates cholesterol-lowering effect. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:7672-7678. [PMID: 21671634 DOI: 10.1021/jf104821b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We investigated in Syrian Golden hamsters the biological impact and its underlying mechanism of single whole grain breads supplemented with 2-3% hydroxypropyl methylcellulose (HPMC), a semisynthetic viscous soluble dietary fiber (SDF) as a substitute for gluten. Hamsters were fed high-fat diets supplemented with 48-65% (w/w) differently ground, freeze-dried single grain breads including whole grain wheat, barley, barley supplemented with HPMC, debranned oat, and oat supplemented with HPMC which were compared to a diet containing microcrystalline cellulose (control). All single grain breads significantly lowered plasma LDL-cholesterol concentrations compared to the control. Enrichment with HPMC further lowered plasma and hepatic cholesterol concentrations. Despite the reduced molecular weight of naturally occurring soluble (1--->3),(1--->4)-β-d-glucan (β-glucan) caused by the bread-making process, whole grain barley breads downregulated hepatic expression of CYP7A1 and HMG-CoAR genes that are responsible for bile acid and cholesterol synthesis, suggesting a possible role of bioactive compounds such as short-chain fatty acids and phenolic compounds from barley bread. Barley bread enriched with HPMC downregulated expression of ABCG5 gene. Taken together, it appears that distinctive modulation of synthesis and excretion of hepatic cholesterol and bile acid contributes to the cholesterol-lowering properties of whole grain barley breads and breads enriched with HPMC. These data suggests that alternative whole grain breads supplemented with HPMC may provide consumers with a staple food that can assist in cholesterol management.
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Affiliation(s)
- Hyunsook Kim
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA 94710, USA.
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Turley SD, Valasek MA, Repa JJ, Dietschy JM. Multiple mechanisms limit the accumulation of unesterified cholesterol in the small intestine of mice deficient in both ACAT2 and ABCA1. Am J Physiol Gastrointest Liver Physiol 2010; 299:G1012-22. [PMID: 20724527 PMCID: PMC2993165 DOI: 10.1152/ajpgi.00190.2010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 08/16/2010] [Indexed: 01/31/2023]
Abstract
Cholesterol homeostasis in the enterocyte is regulated by the interplay of multiple genes that ultimately determines the net amount of cholesterol reaching the circulation from the small intestine. The effect of deleting these genes, particularly acyl CoA:cholesterol acyl transferase 2 (ACAT2), on cholesterol absorption and fecal sterol excretion is well documented. We also know that the intestinal mRNA level for adenosine triphosphate-binding cassette transporter A1 (ABCA1) increases in Acat2(-/-) mice. However, none of these studies has specifically addressed how ACAT2 deficiency impacts the relative proportions of esterified and unesterified cholesterol (UC) in the enterocyte and whether the concurrent loss of ABCA1 might result in a marked buildup of UC. Therefore, the present studies measured the expression of numerous genes and related metabolic parameters in the intestine and liver of ACAT2-deficient mice fed diets containing either added cholesterol or ezetimibe, a selective sterol absorption inhibitor. Cholesterol feeding raised the concentration of UC in the small intestine, and this was accompanied by a significant reduction in the relative mRNA level for Niemann-Pick C1-like 1 (NPC1L1) and an increase in the mRNA level for both ABCA1 and ABCG5/8. All these changes were reversed by ezetimibe. When mice deficient in both ACAT2 and ABCA1 were fed a high-cholesterol diet, the increase in intestinal UC levels was no greater than it was in mice lacking only ACAT2. This resulted from a combination of compensatory mechanisms including diminished NPC1L1-mediated cholesterol uptake, increased cholesterol efflux via ABCG5/8, and possibly rapid cell turnover.
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Affiliation(s)
- Stephen D Turley
- Dept. of Internal Medicine, Univ. of Texas Southwestern Medical School, 5323 Harry Hines Blvd., Dallas, TX 75390-9151, USA.
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Feeding conditions control the expression of genes involved in sterol metabolism in peripheral blood mononuclear cells of normoweight and diet-induced (cafeteria) obese rats. J Nutr Biochem 2010; 21:1127-33. [DOI: 10.1016/j.jnutbio.2009.10.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 09/24/2009] [Accepted: 10/01/2009] [Indexed: 11/22/2022]
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Bartley GE, Yokoyama W, Young SA, Anderson WHK, Hung SC, Albers DR, Langhorst ML, Kim H. Hypocholesterolemic effects of hydroxypropyl methylcellulose are mediated by altered gene expression in hepatic bile and cholesterol pathways of male hamsters. J Nutr 2010; 140:1255-60. [PMID: 20444951 DOI: 10.3945/jn.109.118349] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Hydroxypropyl methylcellulose (HPMC), a semisynthetic, nonfermentable soluble dietary fiber, is not absorbed by the body, but its presence in the intestinal lumen increases fecal fat, sterol, and bile acid excretions and decreases intestinal cholesterol absorption, all of which may indirectly affect hepatic lipid metabolism. We measured the expression of hepatic genes involved in cholesterol, bile acid, and fatty acid metabolism in hamsters fed diets containing 39% of energy as fat and 5% of weight as HPMC or microcrystalline cellulose (control) for 4 wk. HPMC-fed hamsters gained significantly less body weight than the control group but did not differ in food intake. They had significantly lower plasma triglyceride and total-, VLDL-, HDL-, and LDL-cholesterol concentrations and hepatic total lipid, total and free cholesterol and triglyceride concentrations than controls. Compared with controls, HPMC-fed hamsters had greater levels of mRNA for CYP7A1 (cytochrome P450 7A1; 8-fold of control; P < 0.05), CYP51 (lanosterol 14alpha-demethylase; 5.3-fold of control; P < 0.05), and HMG-CoAR (3-hydroxy-3-methylglutaryl CoA reductase; 1.8-fold of control; P < 0.05). The plasma total cholesterol concentrations from both the control and HPMC groups were inversely correlated with expression of hepatic CYP7A1 (r = -0.54; P < 0.05), CYP51 (r = -0.79; P < 0.005), and HMG-CoAR (r = -0.75; P < 0.005) genes. This suggests that HPMC supplementation affected both cholesterol and bile acid synthesis. Our data confirm that altered hepatic expression of lipid metabolism-related genes, possibly due to modulation of fecal bile acid excretion and intestinal cholesterol absorption, contributes to the lipid-lowering effects of HPMC.
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Affiliation(s)
- Glenn E Bartley
- Processed Foods Research, Western Regional Research Center, USDA, Agricultural Research Service, Albany, CA 94710, USA
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A proprotein convertase subtilisin/kexin type 9 neutralizing antibody reduces serum cholesterol in mice and nonhuman primates. Proc Natl Acad Sci U S A 2009; 106:9820-5. [PMID: 19443683 DOI: 10.1073/pnas.0903849106] [Citation(s) in RCA: 311] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates serum LDL cholesterol (LDL-C) by interacting with the LDL receptor (LDLR) and is an attractive therapeutic target for LDL-C lowering. We have generated a neutralizing anti-PCSK9 antibody, mAb1, that binds to an epitope on PCSK9 adjacent to the region required for LDLR interaction. In vitro, mAb1 inhibits PCSK9 binding to the LDLR and attenuates PCSK9-mediated reduction in LDLR protein levels, thereby increasing LDL uptake. A combination of mAb1 with a statin increases LDLR levels in HepG2 cells more than either treatment alone. In wild-type mice, mAb1 increases hepatic LDLR protein levels approximately 2-fold and lowers total serum cholesterol by up to 36%: this effect is not observed in LDLR(-/-) mice. In cynomolgus monkeys, a single injection of mAb1 reduces serum LDL-C by 80%, and a significant decrease is maintained for 10 days. We conclude that anti-PCSK9 antibodies may be effective therapeutics for treating hypercholesterolemia.
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Xie C, Turley SD, Dietschy JM. ABCA1 plays no role in the centripetal movement of cholesterol from peripheral tissues to the liver and intestine in the mouse. J Lipid Res 2009; 50:1316-29. [PMID: 19286647 DOI: 10.1194/jlr.m900024-jlr200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study uses the mouse to explore the role of ABCA1 in the movement of this cholesterol from the peripheral organs to the endocrine glands for hormone synthesis and liver for excretion. The sterol pool in all peripheral organs was constant and equaled 2,218 and 2,269 mg/kg, respectively, in abca1(+/+) and abca1(-/-) mice. Flux of cholesterol from these tissues equaled the rate of synthesis plus the rate of LDL-cholesterol uptake and was 49.9 mg/day/kg in control animals and 62.0 mg/day/kg in abca1(-/-) mice. In the abca1(+/+) animals, this amount of cholesterol moved from HDL into the liver for excretion. In the abca1(-/-) mice, the cholesterol from the periphery also reached the liver but did not use HDL. Fecal excretion of cholesterol was just as high in abac1(-/-) mice (198 mg/day/kg) as in the abac1(+/+) animals (163 mg/day/kg), although the abac1(-/-) mice excreted relatively more neutral than acidic sterols. This study established that ABCA1 plays essentially no role in the turnover of cholesterol in peripheral organs or in the centripetal movement of this sterol to the endocrine glands, liver, and intestinal tract for excretion.
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Affiliation(s)
- Chonglun Xie
- Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, TX 75390-9151, USA
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Appt SE, Törmälä R, Franke AA, Mikkola TS, Tikkanen MJ, Ylikorkala O, Clarkson TB. Soy-tibolone combination - effect on lipids in postmenopausal monkeys and women. Maturitas 2008; 60:216-22. [PMID: 18687539 DOI: 10.1016/j.maturitas.2008.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 06/18/2008] [Accepted: 06/26/2008] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To determine whether co-administration of soy during tibolone treatment would prevent tibolone-induced dyslipoproteinemia in postmenopausal monkeys and women. METHODS Surgically postmenopausal cynomolgus monkeys (n = 18) were assigned randomly to one of four dietary regimens in a Latin Square crossover design, such that all animals received all diets for 14 weeks with a 4-week washout period: (1) casein/lactalbumin (CL); (2) tibolone (Tib, 1.25 mg/day women's equivalent); (3) soy (138 mg isoflavones/day women's equivalent); (4) Soy + Tib. Postmenopausal women on tibolone treatment were randomized to receive soy powder (52 g of soy protein containing 112 mg isoflavones) or placebo (containing 52 g of milk protein) daily in a crossover trial for 8 weeks with a 4-week washout period. RESULTS Monkeys given Tib alone had approximately 14% increase in plasma LDL + VLDL-C; whereas those given soy combined with tibolone had significant ( approximately 22%) reductions. Tib treated monkeys had reductions in plasma HDL-C of about 48% vs. no reductions in Soy + Tib. In postmenopausal women using tibolone, soy reduced plasma LDL-C concentrations by approximately 10% from baseline without a change in HDL-C. CONCLUSIONS Co-administration of soy during tibolone treatment improved the lipoprotein profile in both monkeys and women; however, the effects were more robust in monkeys.
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Affiliation(s)
- Susan E Appt
- Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA.
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Ness GC, Chambers CM. Feedback and Hormonal Regulation of Hepatic 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase: The Concept of Cholesterol Buffering Capacity. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1525-1373.2000.22359.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
The absorption of cholesterol by the proximal small intestine represents a major pathway for the entry of cholesterol into the body pools. This cholesterol is derived primarily from the bile and the diet. In adult humans, typically several hundred milligrams of cholesterol reach the liver from the intestine daily, with the potential to impact the plasma low density lipoprotein-cholesterol (LDL-C) concentration. There are three main phases involved in cholesterol absorption. The first occurs intraluminally and culminates in micellar solubilization of unesterified cholesterol which facilitates its movement up to the brush border membrane (BBM) of the enterocyte. The second phase involves the transport of cholesterol across the BBM by Niemann-Pick C1 Like-1 (NPC1L1), while the third phase entails a series of steps within the enterocyte involving the esterification of cholesterol and its incorporation, along with other lipids and apolipoprotein B48 (apo B48), into nascent chylomicrons (CM). The discovery of the role of NPC1L1 in intestinal sterol transport occurred directly as a consequence of efforts to identify the molecular target of ezetimibe, a novel, potent, and specific inhibitor of sterol absorption that is now widely used in combination therapy with statins for the management of hypercholesterolemia in the general population. Some aspects of the role of NPC1L1 in cholesterol absorption nevertheless remain controversial and are the subject of ongoing research. For example, one report suggests that NPC1L1 is located not in the plasma membrane but intracellularly where it is thought to be involved in cytosolic trafficking of cholesterol, while another concludes that a protein other than NPC1L1 is responsible for the high affinity binding of cholesterol on intestinal BBM. However, other new studies which show that the in vivo responsiveness of different species to ezetimibe correlates with NPC1L1 binding affinity further support the widely held belief that NPC1L1 does facilitate sterol uptake by the enterocyte and is the target of ezetimibe. Added to this is the unequivocal finding that deletion of the gene for NPC1L1 in mice results in a near complete prevention of cholesterol absorption and an accelerated rate of fecal neutral sterol excretion. In summary, the development of ezetimibe and the identification of NPC1L1 as a key player in sterol absorption have taken research on the molecular control of this pathway to an exciting new level. From this it is hoped that we will now be able to determine more precisely what effect, if any, other classes of lipid lowering agents, particularly the statins, might exert on the amount of intestinal cholesterol reaching the liver.
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Affiliation(s)
- Stephen D Turley
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical School, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
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Torres-Gonzalez M, Shrestha S, Sharman M, Freake HC, Volek JS, Fernandez ML. Carbohydrate restriction alters hepatic cholesterol metabolism in guinea pigs fed a hypercholesterolemic diet. J Nutr 2007; 137:2219-23. [PMID: 17885001 DOI: 10.1093/jn/137.10.2219] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The current study was undertaken to evaluate the effect of carbohydrate restriction on hepatic cholesterol metabolism in guinea pigs fed a hypercholesterolemic diet. Hartley male guinea pigs (n = 10 per group) were fed 1 of 3 diets: a diet with a percent energy distribution of 42:23:35 carbohydrate:protein:fat and 0.04% cholesterol (control), a diet with the same macronutrient distribution but with 0.25% cholesterol (HChol), or a carbohydrate-restricted (CR) diet with a percent energy distribution of 11:30:59 carbohydrate:protein:fat and 0.25% cholesterol for 12 wk. There was more accumulation of hepatic cholesterol and triglycerides as well as lower 3-hydroxy-3-methyl glutaryl-CoA reductase messenger RNA abundance in guinea pigs fed the high-cholesterol diets (HChol and CR) (P < 0.01). Guinea pigs fed the CR diet had lower concentrations of hepatic total cholesterol and cholesteryl ester than those fed the HChol diet (P < 0.05). There was no diet effect on hepatic LDL receptor expression. Hepatic acyl CoA cholesteryl acyltransferase (ACAT) activity was lowest in guinea pigs fed the low-cholesterol diet (9.7 +/- 4.8 pmol.min(-1).mg(-1)), intermediate in those fed the CR diet (37.3 +/- 12.4 pmol.min(-1).mg protein(-1)), and highest in guinea pigs fed the HChol diet (55.9 +/- 11.2 pmol.min(-1).mg(-1)). ACAT activity was significantly correlated with hepatic cholesterol (r = 0.715; P < 0.01) and LDL cholesterol (r = 0.59; P < 0.01) for all dietary groups, suggesting a major role of this enzyme in hepatic cholesterol homeostasis and in lipoprotein concentrations. These results indicate that dietary cholesterol increases hepatic lipid accumulation and affects hepatic cholesterol homeostasis. Carbohydrate restriction in the presence of high cholesterol is associated with lower hepatic ACAT activity and an attenuation of hepatic cholesterol accumulation.
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Liu B, Xie C, Richardson JA, Turley SD, Dietschy JM. Receptor-mediated and bulk-phase endocytosis cause macrophage and cholesterol accumulation in Niemann-Pick C disease. J Lipid Res 2007; 48:1710-23. [PMID: 17476031 DOI: 10.1194/jlr.m700125-jlr200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
These studies explored the roles of receptor-mediated and bulk-phase endocytosis as well as macrophage infiltration in the accumulation of cholesterol in the mouse with Niemann-Pick type C (NPC) disease. Uptake of LDL-cholesterol varied from 514 microg/day in the liver to zero in the central nervous system. In animals lacking LDL receptors, liver uptake remained about the same (411 microg/day), but more cholesterol was taken up in extrahepatic organs. This uptake was unaffected by the reductive methylation of LDL and consistent with bulk-phase endocytosis. All tissues accumulated cholesterol in mice lacking NPC1 function, but this accumulation was decreased in adrenal, unchanged in liver, and increased in organs like spleen and lung when LDL receptor function was also deleted. Over 56 days, the spleen and lung accumulated amounts of cholesterol greater than predicted, and these organs were heavily infiltrated with macrophages. This accumulation of both cholesterol and macrophages was increased by deleting LDL receptor function. These observations indicate that both receptor-mediated and bulk-phase endocytosis of lipoproteins, as well as macrophage infiltration, contribute to the cholesterol accumulation seen in NPC disease. These macrophages may also play a role in parenchymal cell death in this syndrome.
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Affiliation(s)
- Benny Liu
- Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, TX 75390-9151, USA
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45
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Garver WS, Jelinek D, Oyarzo JN, Flynn J, Zuckerman M, Krishnan K, Chung BH, Heidenreich RA. Characterization of liver disease and lipid metabolism in the Niemann-Pick C1 mouse. J Cell Biochem 2007; 101:498-516. [PMID: 17216601 DOI: 10.1002/jcb.21200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Niemann-Pick type C1 (NPC1) disease is an autosomal-recessive cholesterol-storage disorder characterized by liver dysfunction, hepatosplenomegaly, and progressive neurodegeneration. The NPC1 gene is expressed in every tissue of the body, with liver expressing the highest amounts of NPC1 mRNA and protein. A number of studies have now indicated that the NPC1 protein regulates the transport of cholesterol from late endosomes/lysosomes to other cellular compartments involved in maintaining intracellular cholesterol homeostasis. The present study characterizes liver disease and lipid metabolism in NPC1 mice at 35 days of age before the development of weight loss and neurological symptoms. At this age, homozygous affected (NPC1(-/-)) mice were characterized with mild hepatomegaly, an elevation of liver enzymes, and an accumulation of liver cholesterol approximately four times that measured in normal (NPC1(+/+)) mice. In contrast, heterozygous (NPC1(+/-)) mice were without hepatomegaly and an elevation of liver enzymes, but the livers had a significant accumulation of triacylglycerol. With respect to apolipoprotein and lipoprotein metabolism, the results indicated only minor alterations in NPC1(-/-) mouse serum. Finally, compared to NPC1(+/+) mouse livers, the amount and processing of SREBP-1 and -2 proteins were significantly increased in NPC1(-/-) mouse livers, suggesting a relative deficiency of cholesterol at the metabolically active pool of cholesterol located at the endoplasmic reticulum. The results from this study further support the hypothesis that an accumulation of lipoprotein-derived cholesterol within late endosomes/lysosomes, in addition to altered intracellular cholesterol homeostasis, has a key role in the biochemical and cellular pathophysiology associated with NPC1 liver disease.
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Affiliation(s)
- William S Garver
- Department of Pediatrics, The University of Arizona, Tucson, AZ 85724, USA.
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Xie C, Richardson JA, Turley SD, Dietschy JM. Cholesterol substrate pools and steroid hormone levels are normal in the face of mutational inactivation of NPC1 protein. J Lipid Res 2006; 47:953-63. [PMID: 16461760 DOI: 10.1194/jlr.m500534-jlr200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mutational inactivation of NPC1 largely blocks the movement of LDL-derived cholesterol from the lysosome to the metabolically active, cytosolic pool of sterol that is the substrate for steroid hormone production. Such a block might, in theory, lead to deficiencies in circulating levels of testosterone, progesterone, and corticosterone. However, there are at least two other sources for cellular cholesterol, de novo synthesis and scavenger receptor class B type I-mediated uptake of HDL cholesteryl ester (CE). In this study, we measured the rates of net cholesterol acquisition by these three pathways in the adrenal, ovary, and testis. In all three organs, the majority (81-98%) of cholesterol acquisition came from the selective uptake of CE from HDL and de novo synthesis. Furthermore, in the npc1(-/-)mouse, the cytosolic storage pool of CE in a tissue such as the adrenal remained constant (approximately 25 mg/g). As a result of these alternative pathways, the plasma concentrations of testosterone (3.5 vs. 2.5 ng/ml), progesterone (8.5 vs. 6.7 ng/ml), and corticosterone (391 vs. 134 ng/ml) were either the same or elevated in the npc1(-/-)mouse, compared with the control animal. Thus, impairment of cholesterol acquisition through the NPC1-dependent, clathrin-coated pit pathway did not limit the availability of cholesterol substrate for steroid hormone synthesis in the steroidogenic cells.
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Affiliation(s)
- Chonglun Xie
- Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, 75390-8887, USA
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Garver WS, Xie C, Repa JJ, Turley SD, Dietschy JM. Niemann-Pick C1 expression is not regulated by the amount of cholesterol flowing through cells in the mouse. J Lipid Res 2005; 46:1745-54. [PMID: 15930512 DOI: 10.1194/jlr.m500130-jlr200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Niemann-Pick C1 (NPC1) protein functions to regulate the transport of cholesterol from late endosomes/lysosomes to other cellular compartments after lipoprotein uptake through the coated-pit pathway. The present study examines the relative expression of NPC1 mRNA and NPC1 protein in different tissues of the mouse in relation to the uptake of total cholesterol carried in chylomicron remnants (CMr-TC), low density lipoproteins (LDL-TC), cholesteryl ester carried in high density lipoproteins (HDL-CE), and cholesterol synthesis. Results from this study demonstrate that the highest relative expression of NPC1 is in the liver, which is also the tissue with the highest uptake of CMr-TC, LDL-TC, HDL-CE, and cholesterol synthesis. However, there was no similar relation in the remaining tissues. To examine the relative expression of NPC1 in relation to the amount of cholesterol that flowed through the coated-pit pathway, mice were fed a diet supplemented with increasing amounts of cholesterol or cholestyramine. The results from this study demonstrated that there was no relation between the relative expression of NPC1 and the amount of cholesterol that flowed through the coated-pit pathway. We conclude that the relative expression of NPC1 is not regulated by the flow of cholesterol through cells in the mouse and is therefore constitutive.
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Affiliation(s)
- William S Garver
- Department of Pediatrics, Arizona Health Sciences Center, University of Arizona, Tucson, AZ 85724, USA.
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Yao L, Woollett LA. Adult sterol metabolism is not affected by a positive sterol balance in the neonatal Golden Syrian hamster. Am J Physiol Regul Integr Comp Physiol 2004; 288:R561-6. [PMID: 15550619 DOI: 10.1152/ajpregu.00353.2004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dietary components impact metabolism early in life. Some of the diet-induced effects are long lasting and can lead to various adult-based diseases. In the current studies, we examined the short-term effects of dietary cholesterol on neonatal hepatic sterol metabolism and the long-term effects that those early-life diets had on sterol metabolism in adulthood. Neonatal hamsters began consuming solid food as a supplement to milk by 5 days of age; diets contained 0 or 2% added cholesterol (wt/wt). By 10 days of age, plasma and liver cholesterol concentrations were 3.2- and 2.5-fold greater, respectively, in the neonates fed cholesterol. Hepatic sterol synthesis rates were suppressed 65% in cholesterol-fed neonates compared with control neonates. By 20 days of age, plasma and liver cholesterol concentrations were still greater and sterol synthesis rates were now suppressed maximally in neonates fed cholesterol compared with control neonates. The expression level of an apolipoprotein B-containing lipoprotein receptor (low-density lipoprotein receptor-related protein) was greater and the mature form of the sterol regulatory element-binding protein-2 was similar in livers of 20-day-old control neonates compared with control neonates at 10 days of age. To test whether the change in sterol balance in the neonatal period had a lasting effect on hepatic sterol metabolism, all animals were weaned on a low-cholesterol diet. At 70 days of age, hepatic sterol synthesis rates, plasma lipoprotein and liver cholesterol concentrations, and bile acid pool sizes and compositions were measured. Sterol balance in the adults was similar between animals fed either diet early in life, as demonstrated by a lack of difference in any parameter measured. Thus, even though dietary cholesterol suppressed hepatic sterol synthesis rates dramatically in the neonatal hamster, the change has little impact on sterol balance later in life.
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Affiliation(s)
- Lihang Yao
- Dept. of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, 2120 East Galbraith Road, Cincinnati, OH 45237-0507, USA
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Tochtrop GP, DeKoster GT, Cistola DP, Covey DF. Synthesis of [3,4-(13)c(2)]-enriched bile salts as NMR probes of protein-ligand interactions. J Org Chem 2002; 67:6764-71. [PMID: 12227809 DOI: 10.1021/jo0259109] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synthetic methodology that allows for incorporation of isotopic carbon at the C-3 and C-4 positions of bile salts is reported. Three [3,4-(13)C(2)]-enriched bile salts were synthesized from either deoxycholic or lithocholic acid. The steroid 3alpha-OH group was oxidized and the A-ring was converted into the Delta(4)-3-ketone. The C-24 carboxylic acid was next converted into the carbonate group and selectively reduced to the alcohol in the presence of the A-ring enone. Following protection of the 24-OH group, the Delta(4)-3-ketone was converted into the A-ring enol lactone. Condensation of the enol lactone with [1,2-(13)C(2)]-enriched acetyl chloride and subsequent Robinson annulation afforded a [3,4-(13)C(2)]-enriched Delta(4)-3-ketone that was subsequently converted back into a 3alpha-hydroxy-5beta-reduced bile steroid. C-7 hydroxylation, when necessary, was achieved via conversion of the Delta(4)-3-ketone into the corresponding Delta(4,6)-dien-3-one, epoxidation of the Delta(6)-double bond, and hydrogenolysis/hydrogenation of the 5,6-epoxy enone system. The [3,4-(13)C(2)]-enriched bile salts were subsequently complexed to human ileal bile acid binding protein (I-BABP), and (1)H-(13)C HSQC spectra were recorded to show the utility of the compounds for investigating the interactions of bile acids with I-BABP.
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Affiliation(s)
- Gregory P Tochtrop
- Department of Molecular Biology & Pharmacology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8103, St. Louis, Missouri 63110, USA
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50
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Xie C, Woollett LA, Turley SD, Dietschy JM. Fatty acids differentially regulate hepatic cholesteryl ester formation and incorporation into lipoproteins in the liver of the mouse. J Lipid Res 2002; 43:1508-19. [PMID: 12235183 DOI: 10.1194/jlr.m200146-jlr200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
These experiments tested the hypothesis that fatty acids (FAs) that drive cholesterol esterification also enhance sterol secretion and were undertaken using a mouse model where lipoprotein-cholesterol output by the liver could be assessed in vivo. The turnover of sterol in the animals was kept constant ( approximately 160 mg/d per kg) while the liver was enriched with the single FAs 8:0, 14:0, 18:1, or 18:2. Under these conditions, the steady-state concentration of cholesteryl ester in the liver varied 6-fold, from 1.2 to 7.9 mg/g, and the expansion of this pool was directly related to the specific FA enriching the liver (FA 18:1>18:2>8:0> 14:0). Secretion of lipoprotein-cholesterol varied 5-fold and was a linear function of the concentration of cholesteryl ester in the liver. These studies demonstrate that unsaturated FAs drive the esterification reaction and enhance lipoprotein cholesterol secretion by the liver under conditions where cholesterol balance across this organ is constant. Thus, individual FAs interact with cholesterol to profoundly regulate both the output and uptake of sterol by the liver, and these effects are articulated through the esterification reaction.
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Affiliation(s)
- Chonglun Xie
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-8887, USA
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