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Back PI, Yu M, Modaresahmadi S, Hajimirzaei S, Zhang Q, Islam MR, Schwendeman AA, La-Beck NM. Immune Implications of Cholesterol-Containing Lipid Nanoparticles. ACS NANO 2024. [PMID: 39388645 DOI: 10.1021/acsnano.4c06369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
The majority of clinically approved nanoparticle-mediated therapeutics are lipid nanoparticles (LNPs), and most of these LNPs are liposomes containing cholesterol. LNP formulations significantly alter the drug pharmacokinetics (PK) due to the propensity of nanoparticles for uptake by macrophages. In addition to readily engulfing LNPs, the high expression of cholesterol hydroxylases and reactive oxygen species (ROS) in macrophages suggests that they will readily produce oxysterols from LNP-associated cholesterol. Oxysterols are a heterogeneous group of cholesterol oxidation products that have potent immune modulatory effects. Oxysterols are implicated in the pathogenesis of atherosclerosis and certain malignancies; they have also been found in commercial liposome preparations. Yet, the in vivo metabolic fate of LNP-associated cholesterol remains unclear. We review herein the mechanisms of cellular uptake, trafficking, metabolism, and immune modulation of endogenous nanometer-sized cholesterol particles (i.e., lipoproteins) that are also relevant for cholesterol-containing nanoparticles. We believe that it would be imperative to better understand the in vivo metabolic fate of LNP-associated cholesterol and the immune implications for LNP-therapeutics. We highlight critical knowledge gaps that we believe need to be addressed in order to develop safer and more efficacious lipid nanoparticle delivery systems.
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Affiliation(s)
- Patricia Ines Back
- Department of Immunotherapeutics and Biotechnology, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas 79601, United States
| | - Minzhi Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Ann Arbor, Michigan 48109, United States
| | - Shadan Modaresahmadi
- Department of Immunotherapeutics and Biotechnology, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas 79601, United States
| | - Sahelosadat Hajimirzaei
- Department of Immunotherapeutics and Biotechnology, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas 79601, United States
| | - Qisheng Zhang
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Md Rakibul Islam
- Department of Immunotherapeutics and Biotechnology, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas 79601, United States
| | - Anna A Schwendeman
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Ann Arbor, Michigan 48109, United States
- Biointerfaces Institute, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Ann Arbor, Michigan 48109, United States
| | - Ninh M La-Beck
- Department of Immunotherapeutics and Biotechnology, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas 79601, United States
- Department of Pharmacy Practice, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas 79601, United States
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Bydlowski SP, Levy D. Association of ABCG5 and ABCG8 Transporters with Sitosterolemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:31-42. [PMID: 38036873 DOI: 10.1007/978-3-031-43883-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Sitosterolemia is a rare genetic lipid disorder, mainly characterized by the accumulation of dietary xenosterols in plasma and tissues. It is caused by inactivating mutations in either ABCG5 or ABCG8 subunits, a subfamily-G ATP-binding cassette (ABCG) transporters. ABCG5/G8 encodes a pair of ABC half transporters that form a heterodimer (G5G8). This heterodimeric ATP-binding cassette (ABC) sterol transporter, ABCG5/G8, is responsible for the hepatobiliary and transintestinal secretion of cholesterol and dietary plant sterols to the surface of hepatocytes and enterocytes, promoting the secretion of cholesterol and xenosterols into the bile and the intestinal lumen. In this way, ABCG5/G8 function in the reverse cholesterol transport pathway and mediate the efflux of cholesterol and xenosterols to high-density lipoprotein and bile salt micelles, respectively. Here, we review the biological characteristics and function of ABCG5/G8, and how the mutations of ABCG5/G8 can cause sitosterolemia, a loss-of-function disorder characterized by plant sterol accumulation and premature atherosclerosis, among other features.
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Affiliation(s)
- Sergio Paulo Bydlowski
- Lipids, Oxidation and Cell Biology Team, Laboratory of Immunology (LIM19), Heart Institute (InCor), Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, Brazil.
- National Institute of Science and Technology in Regenerative Medicine (INCT-Regenera) CNPq, Rio de Janeiro, Brazil.
| | - Debora Levy
- Lipids, Oxidation and Cell Biology Team, Laboratory of Immunology (LIM19), Heart Institute (InCor), Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, Brazil
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Rezaei F, Farhat D, Gursu G, Samnani S, Lee JY. Snapshots of ABCG1 and ABCG5/G8: A Sterol's Journey to Cross the Cellular Membranes. Int J Mol Sci 2022; 24:ijms24010484. [PMID: 36613930 PMCID: PMC9820320 DOI: 10.3390/ijms24010484] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/29/2022] Open
Abstract
The subfamily-G ATP-binding cassette (ABCG) transporters play important roles in regulating cholesterol homeostasis. Recent progress in the structural data of ABCG1 and ABCG5/G8 disclose putative sterol binding sites that suggest the possible cholesterol translocation pathway. ABCG1 and ABCG5/G8 share high similarity in the overall molecular architecture, and both transporters appear to use several unique structural motifs to facilitate cholesterol transport along this pathway, including the phenylalanine highway and the hydrophobic valve. Interestingly, ABCG5/G8 is known to transport cholesterol and phytosterols, whereas ABCG1 seems to exclusively transport cholesterol. Ligand docking analysis indeed suggests a difference in recruiting sterol molecules to the known sterol-binding sites. Here, we further discuss how the different and shared structural features are relevant to their physiological functions, and finally provide our perspective on future studies in ABCG cholesterol transporters.
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Affiliation(s)
- Fatemeh Rezaei
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Danny Farhat
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Gonca Gursu
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Biochemistry Program, Faculty of Science, University of Ottawa, Ottawa, ON K1H 6N5, Canada
| | - Sabrina Samnani
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Biochemistry Program, Faculty of Science, University of Ottawa, Ottawa, ON K1H 6N5, Canada
| | - Jyh-Yeuan Lee
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Correspondence:
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Paalvast Y, Zhou E, Rozendaal YJW, Wang Y, Gerding A, van Dijk TH, de Boer JF, Rensen PCN, van Dijk KW, Kuivenhoven JA, Bakker BM, van Riel NAW, Groen AK. A Systems Analysis of Phenotype Heterogeneity in APOE*3Leiden.CETP Mice Induced by Long-Term High-Fat High-Cholesterol Diet Feeding. Nutrients 2022; 14:nu14224936. [PMID: 36432620 PMCID: PMC9698005 DOI: 10.3390/nu14224936] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 11/23/2022] Open
Abstract
Within the human population, considerable variability exists between individuals in their susceptibility to develop obesity and dyslipidemia. In humans, this is thought to be caused by both genetic and environmental variation. APOE*3-Leiden.CETP mice, as part of an inbred mouse model in which mice develop the metabolic syndrome upon being fed a high-fat high-cholesterol diet, show large inter-individual variation in the parameters of the metabolic syndrome, despite a lack of genetic and environmental variation. In the present study, we set out to resolve what mechanisms could underlie this variation. We used measurements of glucose and lipid metabolism from a six-month longitudinal study on the development of the metabolic syndrome. Mice were classified as mice with either high plasma triglyceride (responders) or low plasma triglyceride (non-responders) at the baseline. Subsequently, we fitted the data to a dynamic computational model of whole-body glucose and lipid metabolism (MINGLeD) by making use of a hybrid modelling method called Adaptations in Parameter Trajectories (ADAPT). ADAPT integrates longitudinal data, and predicts how the parameters of the model must change through time in order to comply with the data and model constraints. To explain the phenotypic variation in plasma triglycerides, the ADAPT analysis suggested a decreased cholesterol absorption, higher energy expenditure and increased fecal fatty acid excretion in non-responders. While decreased cholesterol absorption and higher energy expenditure could not be confirmed, the experimental validation demonstrated that the non-responders were indeed characterized by increased fecal fatty acid excretion. Furthermore, the amount of fatty acids excreted strongly correlated with bile acid excretion, in particular deoxycholate. Since bile acids play an important role in the solubilization of lipids in the intestine, these results suggest that variation in bile acid homeostasis may in part drive the phenotypic variation in the APOE*3-Leiden.CETP mice.
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Affiliation(s)
- Yared Paalvast
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Enchen Zhou
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Yvonne J. W. Rozendaal
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Yanan Wang
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Albert Gerding
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Theo H. van Dijk
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Jan Freark de Boer
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Patrick C. N. Rensen
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Ko Willems van Dijk
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
- Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Jan A. Kuivenhoven
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Barbara M. Bakker
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Natal A. W. van Riel
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Laboratory of Experimental Vascular Medicine, University of Amsterdam, Amsterdam UMC, Meibergdreef, 1105 AZ Amsterdam, The Netherlands
| | - Albert K. Groen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
- Laboratory of Experimental Vascular Medicine, University of Amsterdam, Amsterdam UMC, Meibergdreef, 1105 AZ Amsterdam, The Netherlands
- Correspondence:
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Duan Y, Gong K, Xu S, Zhang F, Meng X, Han J. Regulation of cholesterol homeostasis in health and diseases: from mechanisms to targeted therapeutics. Signal Transduct Target Ther 2022; 7:265. [PMID: 35918332 PMCID: PMC9344793 DOI: 10.1038/s41392-022-01125-5] [Citation(s) in RCA: 104] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 07/04/2022] [Accepted: 07/12/2022] [Indexed: 12/13/2022] Open
Abstract
Disturbed cholesterol homeostasis plays critical roles in the development of multiple diseases, such as cardiovascular diseases (CVD), neurodegenerative diseases and cancers, particularly the CVD in which the accumulation of lipids (mainly the cholesteryl esters) within macrophage/foam cells underneath the endothelial layer drives the formation of atherosclerotic lesions eventually. More and more studies have shown that lowering cholesterol level, especially low-density lipoprotein cholesterol level, protects cardiovascular system and prevents cardiovascular events effectively. Maintaining cholesterol homeostasis is determined by cholesterol biosynthesis, uptake, efflux, transport, storage, utilization, and/or excretion. All the processes should be precisely controlled by the multiple regulatory pathways. Based on the regulation of cholesterol homeostasis, many interventions have been developed to lower cholesterol by inhibiting cholesterol biosynthesis and uptake or enhancing cholesterol utilization and excretion. Herein, we summarize the historical review and research events, the current understandings of the molecular pathways playing key roles in regulating cholesterol homeostasis, and the cholesterol-lowering interventions in clinics or in preclinical studies as well as new cholesterol-lowering targets and their clinical advances. More importantly, we review and discuss the benefits of those interventions for the treatment of multiple diseases including atherosclerotic cardiovascular diseases, obesity, diabetes, nonalcoholic fatty liver disease, cancer, neurodegenerative diseases, osteoporosis and virus infection.
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Affiliation(s)
- Yajun Duan
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.,Key Laboratory of Metabolism and Regulation for Major Diseases of Anhui Higher Education Institutes, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Ke Gong
- Key Laboratory of Metabolism and Regulation for Major Diseases of Anhui Higher Education Institutes, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Suowen Xu
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Feng Zhang
- Key Laboratory of Metabolism and Regulation for Major Diseases of Anhui Higher Education Institutes, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Xianshe Meng
- Key Laboratory of Metabolism and Regulation for Major Diseases of Anhui Higher Education Institutes, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Jihong Han
- Key Laboratory of Metabolism and Regulation for Major Diseases of Anhui Higher Education Institutes, College of Food and Biological Engineering, Hefei University of Technology, Hefei, China. .,College of Life Sciences, Key Laboratory of Bioactive Materials of Ministry of Education, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
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6
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HDL as Bidirectional Lipid Vectors: Time for New Paradigms. Biomedicines 2022; 10:biomedicines10051180. [PMID: 35625916 PMCID: PMC9138557 DOI: 10.3390/biomedicines10051180] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/10/2022] [Accepted: 05/13/2022] [Indexed: 02/06/2023] Open
Abstract
The anti-atherogenic properties of high-density lipoproteins (HDL) have been explained mainly by reverse cholesterol transport (RCT) from peripheral tissues to the liver. The RCT seems to agree with most of the negative epidemiological correlations between HDL cholesterol levels and coronary artery disease. However, therapies designed to increase HDL cholesterol failed to reduce cardiovascular risk, despite their capacity to improve cholesterol efflux, the first stage of RCT. Therefore, the cardioprotective role of HDL may not be explained by RCT, and it is time for new paradigms about the physiological function of these lipoproteins. It should be considered that the main HDL apolipoprotein, apo AI, has been highly conserved throughout evolution. Consequently, these lipoproteins play an essential physiological role beyond their capacity to protect against atherosclerosis. We propose HDL as bidirectional lipid vectors carrying lipids from and to tissues according to their local context. Lipid influx mediated by HDL appears to be particularly important for tissue repair right on site where the damage occurs, including arteries during the first stages of atherosclerosis. In contrast, the HDL-lipid efflux is relevant for secretory cells where the fusion of intracellular vesicles drastically enlarges the cytoplasmic membrane with the potential consequence of impairment of cell function. In such circumstances, HDL could deliver some functional lipids and pick up not only cholesterol but an integral part of the membrane in excess, restoring the viability of the secretory cells. This hypothesis is congruent with the beneficial effects of HDL against atherosclerosis as well as with their capacity to induce insulin secretion and merits experimental exploration.
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Abstract
PURPOSE OF REVIEW The transintestinal cholesterol efflux (TICE) pathway is the second described route for plasma cholesterol fecal elimination. This article summarizes recent TICE research progresses, involving TICE inducers, molecular determinants of this pathway, and its role in lipoprotein metabolism. RECENT FINDINGS TICE is an active pathway in mice, rats, and humans. Kinetic measurements showed that under basal conditions, the relative contribution of TICE in fecal elimination of plasma cholesterol is quantitatively less important than the hepatobiliary pathway. However, the amplitude of TICE can be induced by numerous nutritional factors and pharmacological drugs. More importantly, by contrast with the stimulation of biliary cholesterol excretion that is associated with an increased risk of gallstone formation, TICE appears as a safer therapeutical target. Finally, several independent studies have demonstrated that TICE is actively contributing to the anti-atherogenic reverse cholesterol pathway reinforcing the interest to better understand its mode of action. The discovery of TICE and the understanding of its mode of action open new therapeutical perspectives for patients at high risk of cardiovascular diseases.
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Reardon AJF, Rowan-Carroll A, Ferguson SS, Leingartner K, Gagne R, Kuo B, Williams A, Lorusso L, Bourdon-Lacombe JA, Carrier R, Moffat I, Yauk CL, Atlas E. Potency Ranking of Per- and Polyfluoroalkyl Substances Using High-Throughput Transcriptomic Analysis of Human Liver Spheroids. Toxicol Sci 2021; 184:154-169. [PMID: 34453843 DOI: 10.1101/2020.10.15.341362] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
Per- and polyfluoroalkyl substances (PFAS) are some of the most prominent organic contaminants in human blood. Although the toxicological implications of human exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are well established, data on lesser-understood PFAS are limited. New approach methodologies (NAMs) that apply bioinformatic tools to high-throughput data are being increasingly considered to inform risk assessment for data-poor chemicals. The aim of this study was to compare the potencies (ie, benchmark concentrations: BMCs) of PFAS in primary human liver microtissues (3D spheroids) using high-throughput transcriptional profiling. Gene expression changes were measured using TempO-seq, a templated, multiplexed RNA-sequencing platform. Spheroids were exposed for 1 or 10 days to increasing concentrations of 23 PFAS in 3 subgroups: carboxylates (PFCAs), sulfonates (PFSAs), and fluorotelomers and sulfonamides. PFCAs and PFSAs exhibited trends toward increased transcriptional potency with carbon chain-length. Specifically, longer-chain compounds (7-10 carbons) were more likely to induce changes in gene expression and have lower transcriptional BMCs. The combined high-throughput transcriptomic and bioinformatic analyses support the capability of NAMs to efficiently assess the effects of PFAS in liver microtissues. The data enable potency ranking of PFAS for human liver cell spheroid cytotoxicity and transcriptional changes, and assessment of in vitro transcriptomic points of departure. These data improve our understanding of the possible health effects of PFAS and will be used to inform read-across for human health risk assessment.
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Affiliation(s)
- Anthony J F Reardon
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Stephen S Ferguson
- Biomolecular Screening Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Karen Leingartner
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Remi Gagne
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Byron Kuo
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Luigi Lorusso
- Chemicals and Environmental Health Management Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Julie A Bourdon-Lacombe
- Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Richard Carrier
- Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Ivy Moffat
- Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
- Department of Biochemistry, University of Ottawa, Ottawa, Ontario, Canada
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Rowan-Carroll A, Reardon A, Leingartner K, Gagné R, Williams A, Meier MJ, Kuo B, Bourdon-Lacombe J, Moffat I, Carrier R, Nong A, Lorusso L, Ferguson SS, Atlas E, Yauk C. High-Throughput Transcriptomic Analysis of Human Primary Hepatocyte Spheroids Exposed to Per- and Polyfluoroalkyl Substances as a Platform for Relative Potency Characterization. Toxicol Sci 2021; 181:199-214. [PMID: 33772556 DOI: 10.1093/toxsci/kfab039] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Per- and poly-fluoroalkyl substances (PFAS) are widely found in the environment because of their extensive use and persistence. Although several PFAS are well studied, most lack toxicity data to inform human health hazard and risk assessment. This study focused on 4 model PFAS: perfluorooctanoic acid (PFOA; 8 carbon), perfluorobutane sulfonate (PFBS; 4 carbon), perfluorooctane sulfonate (PFOS; 8 carbon), and perfluorodecane sulfonate (PFDS; 10 carbon). Human primary liver cell spheroids (pooled from 10 donors) were exposed to 10 concentrations of each PFAS and analyzed at 4 time points. The approach aimed to: (1) identify gene expression changes mediated by the PFAS, (2) identify similarities in biological responses, (3) compare PFAS potency through benchmark concentration analysis, and (4) derive bioactivity exposure ratios (ratio of the concentration at which biological responses occur, relative to daily human exposure). All PFAS induced transcriptional changes in cholesterol biosynthesis and lipid metabolism pathways, and predicted PPARα activation. PFOS exhibited the most transcriptional activity and had a highly similar gene expression profile to PFDS. PFBS induced the least transcriptional changes and the highest benchmark concentration (ie, was the least potent). The data indicate that these PFAS may have common molecular targets and toxicities, but that PFOS and PFDS are the most similar. The transcriptomic bioactivity exposure ratios derived here for PFOA and PFOS were comparable to those derived using rodent apical endpoints in risk assessments. These data provide a baseline level of toxicity for comparison with other known PFAS using this testing strategy.
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Affiliation(s)
- Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Anthony Reardon
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Karen Leingartner
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Remi Gagné
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Matthew J Meier
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Byron Kuo
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Julie Bourdon-Lacombe
- Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Ivy Moffat
- Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Richard Carrier
- Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Andy Nong
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Luigi Lorusso
- Chemicals and Environmental Health Management Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Stephen S Ferguson
- U.S. National Institute of Environmental Health Sciences (NIEHS), Ottawa, Ontario K1N 6N5, Canada
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada
| | - Carole Yauk
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, Ontario K1N 6N5, Canada.,Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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10
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van Loon NM, van Wouw SA, Ottenhoff R, Nelson JK, Kingma J, Scheij S, Moeton M, Zelcer N. Regulation of intestinal LDLR by the LXR-IDOL axis. Atherosclerosis 2020; 315:1-9. [DOI: 10.1016/j.atherosclerosis.2020.10.898] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/08/2020] [Accepted: 10/30/2020] [Indexed: 12/29/2022]
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11
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Srivastava RAK, Cefalu AB, Srivastava NS, Averna M. NPC1L1 and ABCG5/8 induction explain synergistic fecal cholesterol excretion in ob/ob mice co-treated with PPAR-α and LXR agonists. Mol Cell Biochem 2020; 473:247-262. [DOI: 10.1007/s11010-020-03826-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 07/04/2020] [Indexed: 12/15/2022]
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Castaño D, Rattanasopa C, Monteiro-Cardoso VF, Corlianò M, Liu Y, Zhong S, Rusu M, Liehn EA, Singaraja RR. Lipid efflux mechanisms, relation to disease and potential therapeutic aspects. Adv Drug Deliv Rev 2020; 159:54-93. [PMID: 32423566 DOI: 10.1016/j.addr.2020.04.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 02/06/2023]
Abstract
Lipids are hydrophobic and amphiphilic molecules involved in diverse functions such as membrane structure, energy metabolism, immunity, and signaling. However, altered intra-cellular lipid levels or composition can lead to metabolic and inflammatory dysfunction, as well as lipotoxicity. Thus, intra-cellular lipid homeostasis is tightly regulated by multiple mechanisms. Since most peripheral cells do not catabolize cholesterol, efflux (extra-cellular transport) of cholesterol is vital for lipid homeostasis. Defective efflux contributes to atherosclerotic plaque development, impaired β-cell insulin secretion, and neuropathology. Of these, defective lipid efflux in macrophages in the arterial walls leading to foam cell and atherosclerotic plaque formation has been the most well studied, likely because a leading global cause of death is cardiovascular disease. Circulating high density lipoprotein particles play critical roles as acceptors of effluxed cellular lipids, suggesting their importance in disease etiology. We review here mechanisms and pathways that modulate lipid efflux, the role of lipid efflux in disease etiology, and therapeutic options aimed at modulating this critical process.
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13
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Cedó L, Farràs M, Lee-Rueckert M, Escolà-Gil JC. Molecular Insights into the Mechanisms Underlying the Cholesterol- Lowering Effects of Phytosterols. Curr Med Chem 2019; 26:6704-6723. [DOI: 10.2174/0929867326666190822154701] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 01/18/2019] [Accepted: 02/22/2019] [Indexed: 12/11/2022]
Abstract
Dietary phytosterols, which comprise plant sterols and stanols, reduce plasma Low-Density Lipoprotein-Cholesterol (LDL-C) levels when given 2 g/day. Since this dose has not been reported to cause health-related side effects in long-term human studies, food products containing these plant compounds are used as potential therapeutic dietary options to reduce LDL-C and cardiovascular disease risk. Several mechanisms have been proposed to explain the cholesterol-lowering action of phytosterols. They may compete with dietary and biliary cholesterol for micellar solubilization in the intestinal lumen, impairing intestinal cholesterol absorption. Recent evidence indicates that phytosterols may also regulate other pathways. Impaired intestinal cholesterol absorption is usually associated with reduced cholesterol transport to the liver, which may reduce the incorporation of cholesterol into Very-Low- Density Lipoprotein (VLDL) particles, thereby lowering the rate of VLDL assembly and secretion. Impaired liver VLDL production may reduce the rate of LDL production. On the other hand, significant evidence supports a role for plant sterols in the Transintestinal Cholesterol Excretion (TICE) pathway, although the exact mechanisms by which they promote the flow of cholesterol from the blood to enterocytes and the intestinal lumen remains unknown. Dietary phytosterols may also alter the conversion of bile acids into secondary bile acids, and may lower the bile acid hydrophobic/hydrophilic ratio, thereby reducing intestinal cholesterol absorption. This article reviews the progress to date in research on the molecular mechanisms underlying the cholesterol-lowering effects of phytosterols.
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Affiliation(s)
- Lídia Cedó
- Institut d'Investigacions Biomediques (IIB) Sant Pau, Barcelona, Spain
| | - Marta Farràs
- Integrative Systems Medicine and Digestive Disease Division, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
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Li J, Pijut SS, Wang Y, Ji A, Kaur R, Temel RE, van der Westhuyzen DR, Graf GA. Simultaneous Determination of Biliary and Intestinal Cholesterol Secretion Reveals That CETP (Cholesteryl Ester Transfer Protein) Alters Elimination Route in Mice. Arterioscler Thromb Vasc Biol 2019; 39:1986-1995. [PMID: 31462090 PMCID: PMC6761010 DOI: 10.1161/atvbaha.119.312952] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 08/13/2019] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Determine the impact of CETP (cholesteryl ester transfer protein) on the route of cholesterol elimination in mice. Approach and Results: We adapted our protocol for biliary cholesterol secretion with published methods for measuring transintestinal cholesterol elimination. Bile was diverted and biliary lipid secretion maintained by infusion of bile acid. The proximal small bowel was perfused with bile acid micelles. In high-fat, high-cholesterol-fed mice, the presence of a CETP transgene increased biliary cholesterol secretion at the expense of transintestinal cholesterol elimination. The increase in biliary cholesterol secretion was not associated with increases in hepatic SR-BI (scavenger receptor BI) or ABCG5 (ATP-binding cassette G5) ABCG8. The decline in intestinal cholesterol secretion was associated with an increase in intestinal Niemann-Pick disease, type C1, gene-like 1 mRNA. Finally, we followed the delivery of HDL (high-density lipoprotein) or LDL (low-density lipoprotein) cholesteryl esters (CE) from plasma to bile and intestinal perfusates. HDL-CE favored the biliary pathway. Following high-fat feeding, the presence of CETP directed HDL-CE away from the bile and towards the intestine. The presence of CETP increased LDL-CE delivery to bile, whereas the appearance of LDL-CE in intestinal perfusate was near the lower limit of detection. CONCLUSIONS Biliary and intestinal cholesterol secretion can be simultaneously measured in mice and used as a model to examine factors that alter cholesterol elimination. Plasma factors, such as CETP, alter the route of cholesterol elimination from the body. Intestinal and biliary cholesterol secretion rates are independent of transhepatic or transintestinal delivery of HDL-CE, whereas LDL-CE was eliminated almost exclusively in the hepatobiliary pathway.
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Affiliation(s)
- Jianing Li
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY
| | - Sonja S Pijut
- Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY
| | - Yuhuan Wang
- Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY
| | - Ailing Ji
- Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY
| | - Rupinder Kaur
- Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY
| | - Ryan E Temel
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY
- Department of Physiology, University of Kentucky, Lexington, KY
| | - Deneys R van der Westhuyzen
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
- Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY
| | - Gregory A Graf
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY
- Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY
- Barnstable Brown Center for Diabetes and Obesity, University of Kentucky, Lexington, KY
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15
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Grefhorst A, Verkade HJ, Groen AK. The TICE Pathway: Mechanisms and Lipid-Lowering Therapies. Methodist Debakey Cardiovasc J 2019; 15:70-76. [PMID: 31049152 DOI: 10.14797/mdcj-15-1-70] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Besides the well-known hepatobiliary pathway of cholesterol excretion into the feces, transintestinal cholesterol excretion (TICE) is a second major pathway through which cholesterol is disposed from the body. In the process of TICE, cholesterol is taken up from lipoprotein particles at the basolateral side of the enterocyte and translocates towards the apical side of the enterocyte. At the apical side, the ATP-binding cassette transporters G5 and G8 form a heterodimer that transports cholesterol into the intestinal lumen. A substantial amount of the secreted cholesterol is likely reabsorbed by the cholesterol influx transporter Niemann-Pick C1-Like 1 (NPC1L1) since recent data indicate that inhibition of NPC1L1 increases the efficacy of TICE for disposal of cholesterol via the feces. The pathways and proteins involved in intracellular cholesterol trafficking in the enterocyte have not yet been identified. Therefore, in addition to discussing known mediators of TICE, this review will also examine potential candidates involved in cholesterol translocation in the enterocyte. Both the cholesterol reuptake and efflux pathways can be influenced by pharmaceutical means; thus, the TICE pathway is a very attractive target to increase cholesterol excretion from the body and prevent or mitigate atherosclerotic cardiovascular disease.
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Affiliation(s)
- Aldo Grefhorst
- AMSTERDAM UNIVERSITY MEDICAL CENTERS, AMSTERDAM, THE NETHERLANDS
| | - Henkjan J Verkade
- UNIVERSITY MEDICAL CENTER GRONINGEN, UNIVERSITY OF GRONINGEN, GRONINGEN, THE NETHERLANDS
| | - Albert K Groen
- AMSTERDAM UNIVERSITY MEDICAL CENTERS, AMSTERDAM, THE NETHERLANDS.,UNIVERSITY MEDICAL CENTER GRONINGEN, UNIVERSITY OF GRONINGEN, GRONINGEN, THE NETHERLANDS
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16
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Yu XH, Zhang DW, Zheng XL, Tang CK. Cholesterol transport system: An integrated cholesterol transport model involved in atherosclerosis. Prog Lipid Res 2018; 73:65-91. [PMID: 30528667 DOI: 10.1016/j.plipres.2018.12.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/30/2018] [Accepted: 12/01/2018] [Indexed: 02/07/2023]
Abstract
Atherosclerosis, the pathological basis of most cardiovascular disease (CVD), is closely associated with cholesterol accumulation in the arterial intima. Excessive cholesterol is removed by the reverse cholesterol transport (RCT) pathway, representing a major antiatherogenic mechanism. In addition to the RCT, other pathways are required for maintaining the whole-body cholesterol homeostasis. Thus, we propose a working model of integrated cholesterol transport, termed the cholesterol transport system (CTS), to describe body cholesterol metabolism. The novel model not only involves the classical view of RCT but also contains other steps, such as cholesterol absorption in the small intestine, low-density lipoprotein uptake by the liver, and transintestinal cholesterol excretion. Extensive studies have shown that dysfunctional CTS is one of the major causes for hypercholesterolemia and atherosclerosis. Currently, several drugs are available to improve the CTS efficiently. There are also several therapeutic approaches that have entered into clinical trials and shown considerable promise for decreasing the risk of CVD. In recent years, a variety of novel findings reveal the molecular mechanisms for the CTS and its role in the development of atherosclerosis, thereby providing novel insights into the understanding of whole-body cholesterol transport and metabolism. In this review, we summarize the latest advances in this area with an emphasis on the therapeutic potential of targeting the CTS in CVD patients.
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Affiliation(s)
- Xiao-Hua Yu
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical Research Experiment Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China
| | - Da-Wei Zhang
- Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada
| | - Xi-Long Zheng
- Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Health Sciences Center, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
| | - Chao-Ke Tang
- Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, Medical Research Experiment Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China.
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17
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Srivastava N, Cefalu AB, Averna M, Srivastava RAK. Lack of Correlation of Plasma HDL With Fecal Cholesterol and Plasma Cholesterol Efflux Capacity Suggests Importance of HDL Functionality in Attenuation of Atherosclerosis. Front Physiol 2018; 9:1222. [PMID: 30271349 PMCID: PMC6142045 DOI: 10.3389/fphys.2018.01222] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/14/2018] [Indexed: 11/13/2022] Open
Abstract
A number of clinical findings suggested HDL-raising as a plausible approach to treat residual risk of CVD. However, lack of CVD risk reduction by elevated HDL cholesterol (HDL-C) through cholesterol ester transfer protein (CETP) inhibition and enhanced risk reduction in apolipoprotein A-I Milano (apoAI-M) individuals with low HDL-C shifted the focus from HDL-C level to HDL function. In the present study, we investigated correlations between HDL-C, HDL function, fecal cholesterol excretion, and ex vivo plasma cholesterol efflux capacity (CEC) in animal models using two HDL modulators, LXR and PPAR-α agonists. In C57Bl mice, LXR agonist, T1317, raised HDL-C by 30%, while PPAR-α agonist, fenofibrate, reduced HDL-C by 30%, but fecal cholesterol showed twofold increase in both cases. CEC showed a 30–40% increase. Combination of LXR and PPAR-α agonists showed no changes in HDL-C, but, interestingly, fecal cholesterol increased by 4.5-fold, and CEC by 40%, suggesting existence of additional pathway for fecal cholesterol excretion. Regression analysis showed a lack of correlation between HDL-C and fecal cholesterol and CEC, while fecal cholesterol showed significant correlation with CEC, a measure of HDL function. ABCA1 and G1, the two important players in RCT showed greater induction with LXR agonist than PPAR-α agonist. HDL-C increased by 40 and 80% in LXR and PPAR-α treated apoA-I transgenic mice, respectively, with 80% increase in fecal cholesterol. A fivefold increase in fecal cholesterol with no correlation with either plasma HDL-C or CEC following co-treatment with LXR and PPAR-α agonists suggested existence of an HDL-independent pathway for body cholesterol elimination. In hyperlipidemic diabetic ob/ob mice also combination of LXR and PPAR-α agonists showed marked increases in fecal cholesterol content (10–20-fold), while HDL-C rise was only 40%, further suggesting HDL-independent elimination of body cholesterol in mice treated with combination of LXR and PPAR-α agonists. Atherosclerosis attenuation by LXR and PPAR-α agonists in LDLr-deficient mice was associated with increased fecal cholesterol, but not HDL-C. However, fecal cholesterol counts showed inverse correlation with aortic cholesteryl ester content. These data suggest: (a) lack of correlation between HDL-C and fecal or aortic cholesterol content; (b) HDL function (CEC) correlated with fecal cholesterol content; (c) association of reduced aortic lipids in LDLr−/− mice with increased fecal cholesterol, but not with HDL-C, and (d) existence of an HDL-independent pathway for fecal cholesterol excretion following co-treatment with LXR and PPAR-α agonists.
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Affiliation(s)
- Neelam Srivastava
- Department of Internal Medicine, University of Palermo, Palermo, Italy
| | - Angelo B Cefalu
- Department of Internal Medicine, University of Palermo, Palermo, Italy
| | - Maurizio Averna
- Department of Internal Medicine, University of Palermo, Palermo, Italy
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18
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Zanoni P, Velagapudi S, Yalcinkaya M, Rohrer L, von Eckardstein A. Endocytosis of lipoproteins. Atherosclerosis 2018; 275:273-295. [PMID: 29980055 DOI: 10.1016/j.atherosclerosis.2018.06.881] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/04/2018] [Accepted: 06/22/2018] [Indexed: 02/06/2023]
Abstract
During their metabolism, all lipoproteins undergo endocytosis, either to be degraded intracellularly, for example in hepatocytes or macrophages, or to be re-secreted, for example in the course of transcytosis by endothelial cells. Moreover, there are several examples of internalized lipoproteins sequestered intracellularly, possibly to exert intracellular functions, for example the cytolysis of trypanosoma. Endocytosis and the subsequent intracellular itinerary of lipoproteins hence are key areas for understanding the regulation of plasma lipid levels as well as the biological functions of lipoproteins. Indeed, the identification of the low-density lipoprotein (LDL)-receptor and the unraveling of its transcriptional regulation led to the elucidation of familial hypercholesterolemia as well as to the development of statins, the most successful therapeutics for lowering of cholesterol levels and risk of atherosclerotic cardiovascular diseases. Novel limiting factors of intracellular trafficking of LDL and the LDL receptor continue to be discovered and to provide drug targets such as PCSK9. Surprisingly, the receptors mediating endocytosis of high-density lipoproteins or lipoprotein(a) are still a matter of controversy or even new discovery. Finally, the receptors and mechanisms, which mediate the uptake of lipoproteins into non-degrading intracellular itineraries for re-secretion (transcytosis, retroendocytosis), storage, or execution of intracellular functions, are largely unknown.
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Affiliation(s)
- Paolo Zanoni
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Srividya Velagapudi
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Mustafa Yalcinkaya
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Lucia Rohrer
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Arnold von Eckardstein
- Institute for Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland; Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
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19
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Afonso MS, Machado RM, Lavrador MS, Quintao ECR, Moore KJ, Lottenberg AM. Molecular Pathways Underlying Cholesterol Homeostasis. Nutrients 2018; 10:E760. [PMID: 29899250 PMCID: PMC6024674 DOI: 10.3390/nu10060760] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 06/10/2018] [Accepted: 06/11/2018] [Indexed: 01/14/2023] Open
Abstract
Cholesterol is an essential molecule that exerts pleiotropic actions. Although its presence is vital to the cell, its excess can be harmful and, therefore, sustaining cholesterol homeostasis is crucial to maintaining proper cellular functioning. It is well documented that high plasma cholesterol concentration increases the risk of atherosclerotic heart disease. In the last decades, several studies have investigated the association of plasma cholesterol concentrations and the risk of cardiovascular diseases as well as the signaling pathways involved in cholesterol homeostasis. Here, we present an overview of several mechanisms involved in intestinal cholesterol absorption, the regulation of cholesterol synthesis and uptake. We also discuss the importance of reverse cholesterol transport and transintestinal cholesterol transport to maintain cholesterol homeostasis and prevent atherosclerosis development. Additionally, we discuss the influence of dietary cholesterol on plasma cholesterol concentration and the new recommendations for cholesterol intake in a context of a healthy dietary pattern.
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Affiliation(s)
- Milessa Silva Afonso
- Marc and Ruti Bell Vascular Biology and Disease Program, Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA.
| | - Roberta Marcondes Machado
- Laboratorio de Lipides (LIM 10), Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP 05403-000, Brazil.
| | - Maria Silvia Lavrador
- Laboratorio de Lipides (LIM 10), Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP 05403-000, Brazil.
| | - Eder Carlos Rocha Quintao
- Laboratorio de Lipides (LIM 10), Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP 05403-000, Brazil.
| | - Kathryn J Moore
- Marc and Ruti Bell Vascular Biology and Disease Program, Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA.
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
| | - Ana Maria Lottenberg
- Laboratorio de Lipides (LIM 10), Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP 05403-000, Brazil.
- Faculdade Israelita de Ciências da Saúde, Albert Einstein, São Paulo, SP 05403-000, Brazil.
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20
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Abstract
PURPOSE OF REVIEW To discuss recent insights into the measurement and cellular basis of transintestinal cholesterol excretion (TICE) in humans and to explore TICE as a therapeutic target for increasing reverse cholesterol transport. RECENT FINDINGS TICE is the net effect of cholesterol excretion by the enterocyte into the intestinal lumen and is the balance between input and output fluxes through the enterocytes. These fluxes are: cholesterol excretion into the intestinal lumen mainly via ATP-binding cassette (ABC) G5/8, cholesterol absorption from the intestine by Niemann-Pick C1 like protein 1, the uptake of plasma lipoproteins by enterocytes at the basolateral membrane, and the excretion of cholesterol in chylomicrons into the lymph. Multiple studies have shown that TICE contributes to fecal neutral sterol (FNS) excretion in humans. TICE can be targeted with plant sterols, liver X receptor agonists, bile acids, ezetimibe, and proprotein convertase subtilisin/kexin type 9 inhibitors. SUMMARY TICE contributes significantly to FNS excretion in humans, independently of the biliary pathway. Knowledge about its underlying cellular mechanisms surges through in-vivo and in-vitro studies in mice and humans. TICE might be an interesting therapeutic target for increasing cholesterol disposal with the feces. Albeit multiple therapeutic options are available, studies showing clinical benefit are still needed.
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Affiliation(s)
| | | | - Albert K Groen
- Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam
- Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands
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21
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Talbot CP, Plat J, Ritsch A, Mensink RP. Determinants of cholesterol efflux capacity in humans. Prog Lipid Res 2018; 69:21-32. [PMID: 29269048 DOI: 10.1016/j.plipres.2017.12.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/09/2017] [Accepted: 12/11/2017] [Indexed: 12/26/2022]
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22
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Kim B, Bae M, Park YK, Ma H, Yuan T, Seeram NP, Lee JY. Blackcurrant anthocyanins stimulated cholesterol transport via post-transcriptional induction of LDL receptor in Caco-2 cells. Eur J Nutr 2017; 57:405-415. [PMID: 28718016 DOI: 10.1007/s00394-017-1506-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 07/07/2017] [Indexed: 12/13/2022]
Abstract
PURPOSES We previously showed that polyphenol-rich blackcurrant extract (BCE) showed a hypocholesterolemic effect in mice fed a high fat diet. As direct cholesterol removal from the body via the intestine has been recently appreciated, we investigated the effect of BCE on the modulation of genes involved in intestinal cholesterol transport using Caco-2 cells as an in vitro model. METHODS Caco-2 cells were treated with BCE to determine its effects on mRNA and protein expression of genes important for intestinal cholesterol transport, low-density lipoprotein (LDL) uptake, cellular cholesterol content, and cholesterol transport from basolateral to apical membrane of Caco-2 cell monolayers. Cells were also treated with anthocyanin-rich or -poor fraction of BCE to determine the role of anthocyanin on BCE effects. RESULTS BCE significantly increased protein levels of LDL receptor (LDLR) without altering its mRNA, which consequently increased LDL uptake into Caco-2 cells. This post-transcriptional induction of LDLR by BCE was markedly attenuated in the presence of rapamycin, an inhibitor of mechanistic target of rapamycin complex 1 (mTORC1). In addition, BCE altered genes involved in cholesterol transport in the enterocytes, including apical and basolateral cholesterol transporters, in such a way that could enhance cholesterol flux from the basolateral to apical side of the enterocytes. Indeed, BCE significantly increased the flux of LDL-derived cholesterol from the basolateral to the apical chamber of Caco-2 monolayer. LDLR protein levels were markedly increased by anthocyanin-rich fraction, but not by anthocyanin-free fraction. CONCLUSION mTORC1-dependent post-transcriptional induction of LDLR by BCE anthocyanins drove the transport of LDL-derived cholesterol to the apical side of the enterocytes. This may represent a potential mechanism for the hypocholesterolemic effect of BCE.
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Affiliation(s)
- Bohkyung Kim
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT, 06269-4017, USA
| | - Minkyung Bae
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT, 06269-4017, USA
| | - Young-Ki Park
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT, 06269-4017, USA
| | - Hang Ma
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, 02881, USA
| | - Tao Yuan
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, 02881, USA
| | - Navindra P Seeram
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, 02881, USA
| | - Ji-Young Lee
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT, 06269-4017, USA.
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23
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High density lipoprotein (HDL) particles from end-stage renal disease patients are defective in promoting reverse cholesterol transport. Sci Rep 2017; 7:41481. [PMID: 28148911 PMCID: PMC5288657 DOI: 10.1038/srep41481] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 12/09/2016] [Indexed: 12/27/2022] Open
Abstract
Atherosclerotic cardiovascular disease (CVD) represents the largest cause of mortality in end-stage renal disease (ESRD). CVD in ESRD is not explained by classical CVD risk factors such as HDL cholesterol mass levels making functional alterations of lipoproteins conceivable. HDL functions in atheroprotection by promoting reverse cholesterol transport (RCT), comprising cholesterol efflux from macrophage foam cells, uptake into hepatocytes and final excretion into the feces. ESRD-HDL (n = 15) were compared to healthy control HDL (n = 15) for their capacity to promote in vitro (i) cholesterol efflux from THP-1 macrophage foam cells and (ii) SR-BI-mediated selective uptake into ldla[SR-BI] cells as well as (iii) in vivo RCT. Compared with HDL from controls, ESRD-HDL displayed a significant reduction in mediating cholesterol efflux (p < 0.001) and SR-BI-mediated selective uptake (p < 0.01), two key steps in RCT. Consistently, also the in vivo capacity of ESRD-HDL to promote RCT when infused into wild-type mice was significantly impaired (p < 0.01). In vitro oxidation of HDL from healthy controls with hypochloric acid was able to fully mimic the impaired biological activities of ESRD-HDL. In conclusion, we demonstrate that HDL from ESRD patients is dysfunctional in key steps as well as overall RCT, likely due to oxidative modification.
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24
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Stöger JL, Boshuizen MCS, Brufau G, Gijbels MJJ, Wolfs IMJ, van der Velden S, Pöttgens CCH, Vergouwe MN, Wijnands E, Beckers L, Goossens P, Kerksiek A, Havinga R, Müller W, Lütjohann D, Groen AK, de Winther MPJ. Deleting myeloid IL-10 receptor signalling attenuates atherosclerosis in LDLR-/- mice by altering intestinal cholesterol fluxes. Thromb Haemost 2016; 116:565-77. [PMID: 27358035 DOI: 10.1160/th16-01-0043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 05/25/2016] [Indexed: 12/27/2022]
Abstract
Inflammatory responses and cholesterol homeostasis are interconnected in atherogenesis. Interleukin (IL)-10 is an important anti-inflammatory cytokine, known to suppress atherosclerosis development. However, the specific cell types responsible for the atheroprotective effects of IL-10 remain to be defined and knowledge on the actions of IL-10 in cholesterol homeostasis is scarce. Here we investigated the functional involvement of myeloid IL-10-mediated atheroprotection. To do so, bone marrow from IL-10 receptor 1 (IL-10R1) wild-type and myeloid IL-10R1-deficient mice was transplanted to lethally irradiated female LDLR-/- mice. Hereafter, mice were given a high cholesterol diet for 10 weeks after which atherosclerosis development and cholesterol metabolism were investigated. In vitro, myeloid IL-10R1 deficiency resulted in a pro-inflammatory macrophage phenotype. However, in vivo significantly reduced lesion size and severity was observed. This phenotype was associated with lower myeloid cell accumulation and more apoptosis in the lesions. Additionally, a profound reduction in plasma and liver cholesterol was observed upon myeloid IL-10R1 deficiency, which was reflected in plaque lipid content. This decreased hypercholesterolaemia was associated with lowered very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels, likely as a response to decreased intestinal cholesterol absorption. In addition, IL-10R1 deficient mice demonstrated substantially higher faecal sterol loss caused by increased non-biliary cholesterol efflux. The induction of this process was linked to impaired ACAT2-mediated esterification of liver and plasma cholesterol. Overall, myeloid cells do not contribute to IL-10-mediated atheroprotection. In addition, this study demonstrates a novel connection between IL-10-mediated inflammation and cholesterol homeostasis in atherosclerosis. These findings make us reconsider IL-10 as a beneficial influence on atherosclerosis.
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MESH Headings
- Animals
- Apoptosis
- Atherosclerosis/etiology
- Atherosclerosis/metabolism
- Atherosclerosis/prevention & control
- Biological Transport, Active
- Cholesterol/metabolism
- Cholesterol, Dietary/administration & dosage
- Disease Models, Animal
- Female
- Hypercholesterolemia/prevention & control
- Inflammation/etiology
- Inflammation/metabolism
- Inflammation/pathology
- Intestinal Mucosa/metabolism
- Macrophages/metabolism
- Macrophages/pathology
- Mice
- Mice, Knockout
- Myeloid Cells/metabolism
- Myeloid Cells/pathology
- Plaque, Atherosclerotic/etiology
- Plaque, Atherosclerotic/metabolism
- Plaque, Atherosclerotic/pathology
- Receptors, Interleukin-10/deficiency
- Receptors, Interleukin-10/genetics
- Receptors, LDL/deficiency
- Receptors, LDL/genetics
- Signal Transduction
- Sterol O-Acyltransferase/metabolism
- Sterol O-Acyltransferase 2
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Menno P J de Winther
- Prof. M. P. J. de Winther, PhD, Experimental Vascular Biology, Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands, Tel.: +31 20 5666762, E-mail:
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25
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Sachdev V, Leopold C, Bauer R, Patankar JV, Iqbal J, Obrowsky S, Boverhof R, Doktorova M, Scheicher B, Goeritzer M, Kolb D, Turnbull AV, Zimmer A, Hoefler G, Hussain MM, Groen AK, Kratky D. Novel role of a triglyceride-synthesizing enzyme: DGAT1 at the crossroad between triglyceride and cholesterol metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1132-1141. [PMID: 27344248 PMCID: PMC4948681 DOI: 10.1016/j.bbalip.2016.06.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/13/2016] [Accepted: 06/22/2016] [Indexed: 12/13/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) is a key enzyme in triacylglycerol (TG) biosynthesis. Here we show that genetic deficiency and pharmacological inhibition of DGAT1 in mice alters cholesterol metabolism. Cholesterol absorption, as assessed by acute cholesterol uptake, was significantly decreased in the small intestine and liver upon DGAT1 deficiency/inhibition. Ablation of DGAT1 in the intestine (I-DGAT1−/−) alone is sufficient to cause these effects. Consequences of I-DGAT1 deficiency phenocopy findings in whole-body DGAT1−/− and DGAT1 inhibitor-treated mice. We show that deficiency/inhibition of DGAT1 affects cholesterol metabolism via reduced chylomicron size and increased trans-intestinal cholesterol excretion. These effects are independent of cholesterol uptake at the apical surface of enterocytes but mediated through altered dietary fatty acid metabolism. Our findings provide insight into a novel role of DGAT1 and identify a pathway by which intestinal DGAT1 deficiency affects whole-body cholesterol homeostasis in mice. Targeting intestinal DGAT1 may represent a novel approach for treating hypercholesterolemia.
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Affiliation(s)
- Vinay Sachdev
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Christina Leopold
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Raimund Bauer
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; Center of Experimental Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jay V Patankar
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Jahangir Iqbal
- Department of Cell Biology, SUNY Downstate Medical Center, 11203 New York, United States
| | - Sascha Obrowsky
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Renze Boverhof
- Departments of Pediatrics, Center for Liver, Digestive, and Metabolic Diseases, University of Groningen, University Medical Center Groningen, 9713 Groningen, The Netherlands
| | - Marcela Doktorova
- Departments of Pediatrics, Center for Liver, Digestive, and Metabolic Diseases, University of Groningen, University Medical Center Groningen, 9713 Groningen, The Netherlands
| | - Bernhard Scheicher
- Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria
| | - Madeleine Goeritzer
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Dagmar Kolb
- Institute of Cell Biology, Histology, and Embryology, Medical University of Graz, 8010 Graz, Austria
| | | | - Andreas Zimmer
- Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria
| | - Gerald Hoefler
- Institute of Pathology, Medical University of Graz, 8010 Graz, Austria
| | - M Mahmood Hussain
- Department of Cell Biology, SUNY Downstate Medical Center, 11203 New York, United States
| | - Albert K Groen
- Departments of Pediatrics, Center for Liver, Digestive, and Metabolic Diseases, University of Groningen, University Medical Center Groningen, 9713 Groningen, The Netherlands
| | - Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria.
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26
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Meriwether D, Sulaiman D, Wagner A, Grijalva V, Kaji I, Williams KJ, Yu L, Fogelman S, Volpe C, Bensinger SJ, Anantharamaiah GM, Shechter I, Fogelman AM, Reddy ST. Transintestinal transport of the anti-inflammatory drug 4F and the modulation of transintestinal cholesterol efflux. J Lipid Res 2016; 57:1175-93. [PMID: 27199144 DOI: 10.1194/jlr.m067025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Indexed: 01/28/2023] Open
Abstract
The site and mechanism of action of the apoA-I mimetic peptide 4F are incompletely understood. Transintestinal cholesterol efflux (TICE) is a process involved in the clearance of excess cholesterol from the body. While TICE is responsible for at least 30% of the clearance of neutral sterols from the circulation into the intestinal lumen, few pharmacological agents have been identified that modulate this pathway. We show first that circulating 4F selectively targets the small intestine (SI) and that it is predominantly transported into the intestinal lumen. This transport of 4F into the SI lumen is transintestinal in nature, and it is modulated by TICE. We also show that circulating 4F increases reverse cholesterol transport from macrophages and cholesterol efflux from lipoproteins via the TICE pathway. We identify the cause of this modulation of TICE either as 4F being a cholesterol acceptor with respect to enterocytes, from which 4F enhances cholesterol efflux, or as 4F being an intestinal chaperone with respect to TICE. Our results assign a novel role for 4F as a modulator of the TICE pathway and suggest that the anti-inflammatory functions of 4F may be a partial consequence of the codependent intestinal transport of both 4F and cholesterol.
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Affiliation(s)
- David Meriwether
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA Department of Medical and Molecular Pharmacology, University of California Los Angeles, Los Angeles, CA
| | - Dawoud Sulaiman
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA Molecular Toxicology Interdepartmental Degree Program, University of California Los Angeles, Los Angeles, CA
| | - Alan Wagner
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Victor Grijalva
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Izumi Kaji
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Kevin J Williams
- Department of Medical and Molecular Pharmacology, University of California Los Angeles, Los Angeles, CA
| | - Liqing Yu
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD
| | - Spencer Fogelman
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Carmen Volpe
- Division of Laboratory Animal Medicine, University of California Los Angeles, Los Angeles, CA
| | - Steven J Bensinger
- Department of Medical and Molecular Pharmacology, University of California Los Angeles, Los Angeles, CA Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA
| | - G M Anantharamaiah
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Ishaiahu Shechter
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Alan M Fogelman
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Srinivasa T Reddy
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA Department of Medical and Molecular Pharmacology, University of California Los Angeles, Los Angeles, CA Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
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27
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Nakano T, Inoue I, Takenaka Y, Ono H, Katayama S, Awata T, Murakoshi T. Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine. PLoS One 2016; 11:e0152207. [PMID: 27023132 PMCID: PMC4811413 DOI: 10.1371/journal.pone.0152207] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/10/2016] [Indexed: 11/19/2022] Open
Abstract
Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1), an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE) assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM)-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to modulate the flux to dispose of endogenous cholesterol efficiently for therapeutic purposes.
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Affiliation(s)
- Takanari Nakano
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
- * E-mail:
| | - Ikuo Inoue
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Yasuhiro Takenaka
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Hiraku Ono
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Shigehiro Katayama
- Department of Diabetes and Endocrinology, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Takuya Awata
- Department of Diabetes, Endocrinology and Metabolism, International University of Health and Welfare Hospital, Nasushiobara-shi, Tochigi, Japan
| | - Takayuki Murakoshi
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
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28
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Cao P, Pan H, Xiao T, Zhou T, Guo J, Su Z. Advances in the Study of the Antiatherogenic Function and Novel Therapies for HDL. Int J Mol Sci 2015. [PMID: 26225968 PMCID: PMC4581191 DOI: 10.3390/ijms160817245] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The hypothesis that raising high-density lipoprotein cholesterol (HDL-C) levels could improve the risk for cardiovascular disease (CVD) is facing challenges. There is multitudinous clear clinical evidence that the latest failures of HDL-C-raising drugs show no clear association with risks for CVD. At the genetic level, recent research indicates that steady-state HDL-C concentrations may provide limited information regarding the potential antiatherogenic functions of HDL. It is evident that the newer strategies may replace therapeutic approaches to simply raise plasma HDL-C levels. There is an urgent need to identify an efficient biomarker that accurately predicts the increased risk of atherosclerosis (AS) in patients and that may be used for exploring newer therapeutic targets. Studies from recent decades show that the composition, structure and function of circulating HDL are closely associated with high cardiovascular risk. A vast amount of data demonstrates that the most important mechanism through which HDL antagonizes AS involves the reverse cholesterol transport (RCT) process. Clinical trials of drugs that specifically target HDL have so far proven disappointing, so it is necessary to carry out review on the HDL therapeutics.
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Affiliation(s)
- Peiqiu Cao
- Key Research Center of Liver Regulation for Hyperlipemia SATCM/Class III, Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China.
| | - Haitao Pan
- Key Research Center of Liver Regulation for Hyperlipemia SATCM/Class III, Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China.
| | - Tiancun Xiao
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, UK.
- Guangzhou Boxabio Ltd., D-106 Guangzhou International Business Incubator, Guangzhou 510530, China.
| | - Ting Zhou
- Guangzhou Boxabio Ltd., D-106 Guangzhou International Business Incubator, Guangzhou 510530, China.
| | - Jiao Guo
- Key Research Center of Liver Regulation for Hyperlipemia SATCM/Class III, Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China.
| | - Zhengquan Su
- Key Research Center of Liver Regulation for Hyperlipemia SATCM/Class III, Laboratory of Metabolism SATCM, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China.
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29
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Temel RE, Brown JM. A new model of reverse cholesterol transport: enTICEing strategies to stimulate intestinal cholesterol excretion. Trends Pharmacol Sci 2015; 36:440-51. [PMID: 25930707 DOI: 10.1016/j.tips.2015.04.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 03/31/2015] [Accepted: 04/06/2015] [Indexed: 01/02/2023]
Abstract
Cardiovascular disease (CVD) remains the largest cause of mortality in most developed countries. Although recent failed clinical trials and Mendelian randomization studies have called into question the high-density lipoprotein (HDL) hypothesis, it remains well accepted that stimulating the process of reverse cholesterol transport (RCT) can prevent or even regress atherosclerosis. The prevailing model for RCT is that cholesterol from the artery wall must be delivered to the liver where it is secreted into bile before leaving the body through fecal excretion. However, many studies have demonstrated that RCT can proceed through a non-biliary pathway known as transintestinal cholesterol excretion (TICE). The goal of this review is to discuss the current state of knowledge of the TICE pathway, with emphasis on points of therapeutic intervention.
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Affiliation(s)
- Ryan E Temel
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536-0509, USA.
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA.
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30
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Blanchard C, Moreau F, Cariou B, Le May C. [Trans-intestinal cholesterol excretion (TICE): a new route for cholesterol excretion]. Med Sci (Paris) 2014; 30:896-901. [PMID: 25311025 DOI: 10.1051/medsci/20143010017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The small intestine plays a crucial role in dietary and biliary cholesterol absorption, as well as its lymphatic secretion as chylomicrons (lipoprotein exogenous way). Recently, a new metabolic pathway called TICE (trans-intestinal excretion of cholesterol) that plays a central role in cholesterol metabolism has emerged. TICE is an inducible way, complementary to the hepatobiliary pathway, allowing the elimination of the plasma cholesterol directly into the intestine lumen through the enterocytes. This pathway is poorly characterized but several molecular actors of TICE have been recently identified. Although it is a matter of debate, two independent studies suggest that TICE is involved in the anti-atherogenic reverse cholesterol transport pathway. Thus, TICE is an innovative drug target to reduce -cardiovascular diseases.
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Affiliation(s)
- Claire Blanchard
- IRS-UN, institut du thorax, unité Inserm UMR 1087/CNRS UMR 6291, 8, quai Moncousu, 44007 Nantes Cedex 1, France
| | - François Moreau
- IRS-UN, institut du thorax, unité Inserm UMR 1087/CNRS UMR 6291, 8, quai Moncousu, 44007 Nantes Cedex 1, France
| | - Bertrand Cariou
- IRS-UN, institut du thorax, unité Inserm UMR 1087/CNRS UMR 6291, 8, quai Moncousu, 44007 Nantes Cedex 1, France
| | - Cédric Le May
- IRS-UN, institut du thorax, unité Inserm UMR 1087/CNRS UMR 6291, 8, quai Moncousu, 44007 Nantes Cedex 1, France
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31
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Birner-Gruenberger R, Schittmayer M, Holzer M, Marsche G. Understanding high-density lipoprotein function in disease: recent advances in proteomics unravel the complexity of its composition and biology. Prog Lipid Res 2014; 56:36-46. [PMID: 25107698 DOI: 10.1016/j.plipres.2014.07.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/21/2014] [Accepted: 07/24/2014] [Indexed: 10/24/2022]
Abstract
Although the epidemiology of high-density lipoprotein (HDL) cholesterol and cardiovascular risk has been consistent, pharmacologic interventions to increase HDL-cholesterol by delaying HDL catabolism did not translate into reduction in cardiovascular risk. HDL particles are small, protein-rich when compared to other plasma lipoprotein classes. Latest progresses in proteomics technology have dramatically increased our understanding of proteins carried by HDL. In addition to proteins with well-established functions in lipid transport, iron transport proteins, members of the complement pathway, and proteins involved in immune function and acute phase response were repeatedly identified on HDL particles. With the unraveling of the complexity of the HDL proteome, different laboratories have started to monitor its changes in various disease states. In addition, dynamic aspects of HDL subgroups are being discovered. These recent studies clearly illustrate the promise of HDL proteomics for deriving new biomarkers for disease diagnosis and to measure the effectiveness of current and future treatment regimens. This review summarizes recent advances in proteomics and lipidomics helping to understand HDL function in health and disease.
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Affiliation(s)
- Ruth Birner-Gruenberger
- Institute of Pathology, Medical University of Graz, Graz, Austria; Omics Center Graz, BioTechMed, Graz, Austria.
| | - Matthias Schittmayer
- Institute of Pathology, Medical University of Graz, Graz, Austria; Omics Center Graz, BioTechMed, Graz, Austria
| | - Michael Holzer
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Gunther Marsche
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria.
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32
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Ghosh S, Bie J, Wang J, Yuan Q, Ghosh SS. Cholesterol removal from plaques and elimination from the body: change in paradigm to reduce risk for heart disease. ACTA ACUST UNITED AC 2014. [DOI: 10.2217/clp.14.35] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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33
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Degirolamo C, Sabbà C, Moschetta A. Intestinal nuclear receptors in HDL cholesterol metabolism. J Lipid Res 2014; 56:1262-70. [PMID: 25070952 DOI: 10.1194/jlr.r052704] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Indexed: 12/18/2022] Open
Abstract
The intestine plays a pivotal role in cholesterol homeostasis by functioning as an absorptive and secretory organ in the reverse cholesterol transport pathway. Enterocytes control cholesterol absorption, apoAI synthesis, HDL biogenesis, and nonbiliary cholesterol fecal disposal. Thus, intestine-based therapeutic interventions may hold promise in the management of diseases driven by cholesterol overload. Lipid-sensing nuclear receptors (NRs) are highly expressed in the intestinal epithelium and regulate transcriptionally the handling of cholesterol by the enterocytes. Here, we discuss the NR regulation of cholesterol fluxes across the enterocytes with special emphasis on NR exploitation as a bona fide novel HDL-raising strategy.
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Affiliation(s)
- Chiara Degirolamo
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Tumori "Giovanni Paolo II", 70124 Bari, Italy
| | - Carlo Sabbà
- Clinica Medica "Cesare Frugoni", Department of Interdisciplinary Medicine, University of Bari "Aldo Moro", 70124 Bari, Italy
| | - Antonio Moschetta
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Tumori "Giovanni Paolo II", 70124 Bari, Italy Clinica Medica "Cesare Frugoni", Department of Interdisciplinary Medicine, University of Bari "Aldo Moro", 70124 Bari, Italy
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34
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Marshall SM, Gromovsky AD, Kelley KL, Davis MA, Wilson MD, Lee RG, Crooke RM, Graham MJ, Rudel LL, Brown JM, Temel RE. Acute sterol o-acyltransferase 2 (SOAT2) knockdown rapidly mobilizes hepatic cholesterol for fecal excretion. PLoS One 2014; 9:e98953. [PMID: 24901470 PMCID: PMC4047063 DOI: 10.1371/journal.pone.0098953] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 05/09/2014] [Indexed: 02/05/2023] Open
Abstract
The primary risk factor for atherosclerotic cardiovascular disease is LDL cholesterol, which can be reduced by increasing cholesterol excretion from the body. Fecal cholesterol excretion can be driven by a hepatobiliary as well as a non-biliary pathway known as transintestinal cholesterol efflux (TICE). We previously showed that chronic knockdown of the hepatic cholesterol esterifying enzyme sterol O-acyltransferase 2 (SOAT2) increased fecal cholesterol loss via TICE. To elucidate the initial events that stimulate TICE, C57Bl/6 mice were fed a high cholesterol diet to induce hepatic cholesterol accumulation and were then treated for 1 or 2 weeks with an antisense oligonucleotide targeting SOAT2. Within 2 weeks of hepatic SOAT2 knockdown (SOAT2HKD), the concentration of cholesteryl ester in the liver was reduced by 70% without a reciprocal increase in hepatic free cholesterol. The rapid mobilization of hepatic cholesterol stores resulted in a ∼ 2-fold increase in fecal neutral sterol loss but no change in biliary cholesterol concentration. Acute SOAT2HKD increased plasma cholesterol carried primarily in lipoproteins enriched in apoB and apoE. Collectively, our data suggest that acutely reducing SOAT2 causes hepatic cholesterol to be swiftly mobilized and packaged onto nascent lipoproteins that feed cholesterol into the TICE pathway for fecal excretion.
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Affiliation(s)
- Stephanie M. Marshall
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Anthony D. Gromovsky
- Department of Cellular and Molecular Medicine, Cleveland Clinic Foundation – Lerner Research Institute, Cleveland, Ohio, United States of America
| | - Kathryn L. Kelley
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Matthew A. Davis
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Martha D. Wilson
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Richard G. Lee
- Cardiovascular Group, Antisense Drug Discovery, Isis Pharmaceuticals, Carlsbad, California, United States of America
| | - Rosanne M. Crooke
- Cardiovascular Group, Antisense Drug Discovery, Isis Pharmaceuticals, Carlsbad, California, United States of America
| | - Mark J. Graham
- Cardiovascular Group, Antisense Drug Discovery, Isis Pharmaceuticals, Carlsbad, California, United States of America
| | - Lawrence L. Rudel
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - J. Mark Brown
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Department of Cellular and Molecular Medicine, Cleveland Clinic Foundation – Lerner Research Institute, Cleveland, Ohio, United States of America
| | - Ryan E. Temel
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, Kentucky, United States of America
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35
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Mangat R, Proctor SD. Emerging pathways in the regulation of whole body cholesterol flux: therapeutic opportunities to target atherosclerosis? J Lipid Res 2014; 55:796-7. [PMID: 24670991 DOI: 10.1194/jlr.e049502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Rabban Mangat
- Metabolic and Cardiovascular Diseases Laboratory, Molecular and Cell Biology of Lipids Group, Alberta Diabetes and Mazankowski Heart Institutes, University of Alberta, Edmonton, Alberta, Canada
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36
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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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37
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Dikkers A, Annema W, de Boer JF, Iqbal J, Hussain MM, Tietge UJF. Differential impact of hepatic deficiency and total body inhibition of MTP on cholesterol metabolism and RCT in mice. J Lipid Res 2014; 55:816-25. [PMID: 24511105 DOI: 10.1194/jlr.m042986] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Because apoB-containing lipoproteins are pro-atherogenic and their secretion by liver and intestine largely depends on microsomal triglyceride transfer protein (MTP) activity, MTP inhibition strategies are actively pursued. How decreasing the secretion of apoB-containing lipoproteins affects intracellular rerouting of cholesterol is unclear. Therefore, the aim of the present study was to determine the effects of reducing either systemic or liver-specific MTP activity on cholesterol metabolism and reverse cholesterol transport (RCT) using a pharmacological MTP inhibitor or a genetic model, respectively. Plasma total cholesterol and triglyceride levels were decreased in both MTP inhibitor-treated and liver-specific MTP knockout (L-Mttp(-/-)) mice (each P < 0.001). With both inhibition approaches, hepatic cholesterol as well as triglyceride content was consistently increased (each P < 0.001), while biliary cholesterol and bile acid secretion remained unchanged. A small but significant decrease in fecal bile acid excretion was observed in inhibitor-treated mice (P < 0.05), whereas fecal neutral sterol excretion was substantially increased by 75% (P < 0.001), conceivably due to decreased intestinal absorption. In contrast, in L-Mttp(-/-) mice both fecal neutral sterol and bile acid excretion remained unchanged. However, while total RCT increased in inhibitor-treated mice (P < 0.01), it surprisingly decreased in L-Mttp(-/-) mice (P < 0.05). These data demonstrate that: i) pharmacological MTP inhibition increases RCT, an effect that might provide additional clinical benefit of MTP inhibitors; and ii) decreasing hepatic MTP decreases RCT, pointing toward a potential contribution of hepatocyte-derived VLDLs to RCT.
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Affiliation(s)
- Arne Dikkers
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Abstract
PURPOSE OF REVIEW Reverse cholesterol transport (RCT) is considered a significant component of the atheroprotective effects of HDL. Methods for quantifying flux through the RCT pathway have not been available until recently. There is a need to improve our understanding of HDL function, including the role of RCT in general and individual steps of RCT in particular, on atherosclerosis. This review highlights new information about cholesterol flux through the RCT pathway. RECENT FINDINGS Recent clinical studies have demonstrated several important quantitative features of cholesterol fluxes in vivo, providing insight into variability and control of specific components of the RCT pathway. The findings illustrate the independent nature of individual steps in the RCT pathway and their apparently weak relationship to plasma HDL cholesterol levels. Nonclinical studies provide some mechanistic data re-enforcing the importance of apoB particles in RCT and role roles for serum albumin and erythrocytes in free cholesterol flux. These findings suggest that the HDL-centric view of RCT may need revision. SUMMARY The constellation of known lipoproteins and other players involved in this pathway continues to increase. Further research, particularly in humans, is needed in order to understand which parts of the RCT pathway are most relevant to the pathophysiology and treatment of atherosclerosis.
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Affiliation(s)
- Marc Hellerstein
- aKineMed, Inc., Emeryville bDepartment of Nutritional Sciences and Toxicology, University of California, Berkeley cDepartment of Medicine, Division of Endocrinology and Metabolism, University of California, San Francisco, California, USA
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Marshall SM, Kelley KL, Davis MA, Wilson MD, McDaniel AL, Lee RG, Crooke RM, Graham MJ, Rudel LL, Brown JM, Temel RE. Reduction of VLDL secretion decreases cholesterol excretion in niemann-pick C1-like 1 hepatic transgenic mice. PLoS One 2014; 9:e84418. [PMID: 24404162 PMCID: PMC3880293 DOI: 10.1371/journal.pone.0084418] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 11/07/2013] [Indexed: 12/25/2022] Open
Abstract
An effective way to reduce LDL cholesterol, the primary risk factor of atherosclerotic cardiovascular disease, is to increase cholesterol excretion from the body. Our group and others have recently found that cholesterol excretion can be facilitated by both hepatobiliary and transintestinal pathways. However, the lipoprotein that moves cholesterol through the plasma to the small intestine for transintestinal cholesterol efflux (TICE) is unknown. To test the hypothesis that hepatic very low-density lipoproteins (VLDL) support TICE, antisense oligonucleotides (ASO) were used to knockdown hepatic expression of microsomal triglyceride transfer protein (MTP), which is necessary for VLDL assembly. While maintained on a high cholesterol diet, Niemann-Pick C1-like 1 hepatic transgenic (L1Tg) mice, which predominantly excrete cholesterol via TICE, and wild type (WT) littermates were treated with control ASO or MTP ASO. In both WT and L1Tg mice, MTP ASO decreased VLDL triglyceride (TG) and cholesterol secretion. Regardless of treatment, L1Tg mice had reduced biliary cholesterol compared to WT mice. However, only L1Tg mice treated with MTP ASO had reduced fecal cholesterol excretion. Based upon these findings, we conclude that VLDL or a byproduct such as LDL can move cholesterol from the liver to the small intestine for TICE.
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Affiliation(s)
- Stephanie M. Marshall
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Department of Cellular and Molecular Medicine, Cleveland Clinic Foundation – Lerner Research Institute, Cleveland, Ohio, United States of America
| | - Kathryn L. Kelley
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Matthew A. Davis
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Martha D. Wilson
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Allison L. McDaniel
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Richard G. Lee
- Cardiovascular Group, Antisense Drug Discovery, Isis Pharmaceuticals, Carlsbad, California, United States of America
| | - Rosanne M. Crooke
- Cardiovascular Group, Antisense Drug Discovery, Isis Pharmaceuticals, Carlsbad, California, United States of America
| | - Mark J. Graham
- Cardiovascular Group, Antisense Drug Discovery, Isis Pharmaceuticals, Carlsbad, California, United States of America
| | - Lawrence L. Rudel
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - J. Mark Brown
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Department of Cellular and Molecular Medicine, Cleveland Clinic Foundation – Lerner Research Institute, Cleveland, Ohio, United States of America
| | - Ryan E. Temel
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, Kentucky, United States of America
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Dávalos A, Fernández-Hernando C. From evolution to revolution: miRNAs as pharmacological targets for modulating cholesterol efflux and reverse cholesterol transport. Pharmacol Res 2013; 75:60-72. [PMID: 23435093 PMCID: PMC3825518 DOI: 10.1016/j.phrs.2013.02.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 02/11/2013] [Indexed: 02/09/2023]
Abstract
There has been strong evolutionary pressure to ensure that an animal cell maintains levels of cholesterol within tight limits for normal function. Imbalances in cellular cholesterol levels are a major player in the development of different pathologies associated to dietary excess. Although epidemiological studies indicate that elevated levels of high-density lipoprotein (HDL)-cholesterol reduce the risk of cardiovascular disease, recent genetic evidence and pharmacological therapies to raise HDL levels do not support their beneficial effects. Cholesterol efflux as the first and probably the most important step in reverse cholesterol transport is an important biological process relevant to HDL function. Small non-coding RNAs (microRNAs), post-transcriptional control different aspects of cellular cholesterol homeostasis including cholesterol efflux. miRNA families miR-33, miR-758, miR-10b, miR-26 and miR-106b directly modulates cholesterol efflux by targeting the ATP-binding cassette transporter A1 (ABCA1). Pre-clinical studies with anti-miR therapies to inhibit some of these miRNAs have increased cellular cholesterol efflux, reverse cholesterol transport and reduce pathologies associated to dyslipidemia. Although miRNAs as therapy have benefits from existing antisense technology, different obstacles need to be solved before we incorporate such research into clinical care. Here we focus on the clinical potential of miRNAs as therapeutic target to increase cholesterol efflux and reverse cholesterol transport as a new alternative to ameliorate cholesterol-related pathologies.
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Tietge UJF, Groen AK. Role the TICE?: advancing the concept of transintestinal cholesterol excretion. Arterioscler Thromb Vasc Biol 2013; 33:1452-3. [PMID: 23766383 DOI: 10.1161/atvbaha.113.301562] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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The role of the gut in reverse cholesterol transport--focus on the enterocyte. Prog Lipid Res 2013; 52:317-28. [PMID: 23608233 DOI: 10.1016/j.plipres.2013.04.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/01/2013] [Accepted: 04/10/2013] [Indexed: 11/20/2022]
Abstract
In the arterial intima, macrophages become cholesterol-enriched foam cells and atherosclerotic lesions are generated. This atherogenic process can be attenuated, prevented, or even reversed by HDL particles capable of initiating a multistep pathway known as the macrophage-specific reverse cholesterol transport. The macrophage-derived cholesterol released to HDL is taken up by the liver, secreted into the bile, and ultimately excreted in the feces. Importantly, the absorptive epithelial cells lining the lumen of the small intestine, the enterocytes, express several membrane-associated proteins which mediate the influx of luminal cholesterol and its subsequent efflux at their apical and basolateral sides. Moreover, generation of intestinal HDL and systemic effects of the gut microbiota recently revealed a direct link between the gut and the cholesterol cargo of peripheral macrophages. This review summarizes experimental evidence establishing that the reverse cholesterol transport pathway which initiates in macrophages is susceptible to modulation in the small intestine. We also describe four paths which govern cholesterol passage across the enterocyte and define a role for the gut in the regulation of reverse cholesterol transport. Understanding the concerted function of these paths may be useful when designing therapeutic strategies aimed at removing cholesterol from the foam cells which occupy atherosclerotic lesions.
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Bura KS, Lord C, Marshall S, McDaniel A, Thomas G, Warrier M, Zhang J, Davis MA, Sawyer JK, Shah R, Wilson MD, Dikkers A, Tietge UJF, Collet X, Rudel LL, Temel RE, Brown JM. Intestinal SR-BI does not impact cholesterol absorption or transintestinal cholesterol efflux in mice. J Lipid Res 2013; 54:1567-1577. [PMID: 23564696 DOI: 10.1194/jlr.m034454] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Reverse cholesterol transport (RCT) can proceed through the classic hepatobiliary route or through the nonbiliary transintestinal cholesterol efflux (TICE) pathway. Scavenger receptor class B type I (SR-BI) plays a critical role in the classic hepatobiliary route of RCT. However, the role of SR-BI in TICE has not been studied. To examine the role of intestinal SR-BI in TICE, sterol balance was measured in control mice and mice transgenically overexpressing SR-BI in the proximal small intestine (SR-BI(hApoCIII-ApoAIV-Tg)). SR-BI(hApoCIII-ApoAIV-Tg) mice had significantly lower plasma cholesterol levels compared with wild-type controls, yet SR-BI(hApoCIII-ApoAIV-Tg) mice had normal fractional cholesterol absorption and fecal neutral sterol excretion. Both in the absence or presence of ezetimibe, intestinal SR-BI overexpression had no impact on the amount of cholesterol excreted in the feces. To specifically study effects of intestinal SR-BI on TICE we crossed SR-BI(hApoCIII-ApoAIV-Tg) mice into a mouse model that preferentially utilized the TICE pathway for RCT (Niemann-Pick C1-like 1 liver transgenic), and likewise found no alterations in cholesterol absorption or fecal sterol excretion. Finally, mice lacking SR-BI in all tissues also exhibited normal cholesterol absorption and fecal cholesterol disposal. Collectively, these results suggest that SR-BI is not rate limiting for intestinal cholesterol absorption or for fecal neutral sterol loss through the TICE pathway.
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Affiliation(s)
- Kanwardeep S Bura
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Caleb Lord
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Stephanie Marshall
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Allison McDaniel
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Gwyn Thomas
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Manya Warrier
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Jun Zhang
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Matthew A Davis
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Janet K Sawyer
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Ramesh Shah
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Martha D Wilson
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Arne Dikkers
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Uwe J F Tietge
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Xavier Collet
- INSERM U1048, Institute of Metabolic and Cardiovascular Diseases of Rangueil Hospital, BP 84225, Toulouse, France
| | - Lawrence L Rudel
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Ryan E Temel
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC.
| | - J Mark Brown
- Department of Pathology, Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC.
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Le May C, Berger JM, Lespine A, Pillot B, Prieur X, Letessier E, Hussain MM, Collet X, Cariou B, Costet P. Transintestinal cholesterol excretion is an active metabolic process modulated by PCSK9 and statin involving ABCB1. Arterioscler Thromb Vasc Biol 2013; 33:1484-93. [PMID: 23559630 DOI: 10.1161/atvbaha.112.300263] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Transintestinal cholesterol excretion (TICE) is an alternate pathway to hepatobiliary secretion. Our study aimed at identifying molecular mechanisms of TICE. APPROACH AND RESULTS We studied TICE ex vivo in mouse and human intestinal explants, and in vivo after bile diversion and intestinal cannulation in mice. We provide the first evidence that both low-density lipoprotein (LDL) and high-density lipoprotein deliver cholesterol for TICE in human and mouse jejunal explants at the basolateral side. Proprotein convertase subtilisin kexin type 9 (PCSK9)(-/-) mice and intestinal explants show increased LDL-TICE, and acute injection of PCSK9 decreases TICE in vivo, suggesting that PCSK9 is a repressor of TICE. The acute repression was dependent on the LDL receptor (LDLR). Further, TICE was increased when mice were treated with lovastatin. These data point to an important role for LDLR in TICE. However, LDLR(-/-) mice showed increased intestinal LDL uptake, contrary to what is observed in the liver, and tended to have higher TICE. We interpret these data to suggest that there might be at least 2 mechanisms contributing to TICE; 1 involving LDL receptors and other unidentified mechanisms. Acute modulation of LDLR affects TICE, but chronic deficiency is compensated for most likely by the upregulation of the unknown mechanisms. Using mice deficient for apical multidrug active transporter ATP-binding cassette transporter B1 a and b, and its inhibitor, we show that these apical transporters contribute significantly to TICE. CONCLUSIONS TICE is operative in human jejunal explants. It is a metabolically active process that can be acutely regulated, inversely related to cholesterolemia, and pharmacologically activated by statins.
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Affiliation(s)
- Cédric Le May
- INSERM, UMR 1087, CNRS UMR 6291, Nantes F-44000, France
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Leança CC, Nunes VS, Nakandakare ER, de Faria EC, Quintao ECR. Does plasma HDL-C concentration interact with whole-body cholesterol metabolism? Nutr Metab Cardiovasc Dis 2013; 23:279-284. [PMID: 23333727 DOI: 10.1016/j.numecd.2012.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 12/04/2012] [Accepted: 12/06/2012] [Indexed: 01/08/2023]
Abstract
This review examines the interactions between plasma high density lipoprotein (HDL) metabolism and whole-body cholesterol economy. More specifically, this review addresses three questions: 1) does plasma HDL-C concentration correlate with the parameters of whole-body cholesterol metabolism? 2) Do variations in cholesterol metabolism interfere with plasma HDL-C concentrations? 3) Are the markers of cholesterol synthesis and intestinal absorption specifically under the control of plasma HDL? The following answers were provided to each question, respectively: 1) plasma HDL influences whole-body cholesterol synthesis rate but the evidence that HDL modifies the total amount of cholesterol absorbed by the intestine is not clearly supported by present investigations; 2) there are suggestions that changes in whole body cholesterol metabolism rates do not interfere with plasma HDL-C concentrations; 3) markers of cholesterol synthesis and absorption may specifically be controlled by plasma HDL-C concentrations regarding the genetic causes of extremely low HDL-C concentrations, although within the general population plasma HDL-C concentration is likely ascribed to insulin resistance or diabetes mellitus.
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Affiliation(s)
- C C Leança
- Lipids Laboratory (LIM-10), Endocrinology and Metabolism Division of Hospital das Clinicas, Faculty of Medical Sciences, University of Sao Paulo, Av. Dr. Arnaldo 455, Room 3305, 01246-000 São Paulo, SP, Brazil
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Marsche G, Saemann MD, Heinemann A, Holzer M. Inflammation alters HDL composition and function: Implications for HDL-raising therapies. Pharmacol Ther 2013; 137:341-51. [DOI: 10.1016/j.pharmthera.2012.12.001] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Kockx M, Jessup W, Kritharides L. Getting to the 'guts' of the matter: intestinal control of lipid metabolism. Curr Opin Lipidol 2013; 24:105-6. [PMID: 23298966 DOI: 10.1097/mol.0b013e32835c7b5f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wegner CJ, Kim B, Lee J. Trust your gut: galvanizing nutritional interest in intestinal cholesterol metabolism for protection against cardiovascular diseases. Nutrients 2013; 5:208-22. [PMID: 23325147 PMCID: PMC3571644 DOI: 10.3390/nu5010208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/09/2013] [Accepted: 01/11/2013] [Indexed: 02/08/2023] Open
Abstract
Recent studies have demonstrated that the intestine is a key target organ for overall health and longevity. Complementing these studies is the discovery of the trans-intestinal cholesterol efflux pathway and the emerging role of the intestine in reverse cholesterol transport. The surfacing dynamics of the regulation of cholesterol metabolism in the intestine provides an attractive platform for intestine-specific nutritional intervention strategies to lower blood cholesterol levels for protection against cardiovascular diseases. Notably, there is mounting evidence that stimulation of pathways associated with calorie restriction may have a large effect on the regulation of cholesterol removal by the intestine. However, intestinal energy metabolism, specifically the idiosyncrasies surrounding intestinal responses to energy deprivation, is poorly understood. The goal of this paper is to review recent insights into cholesterol regulation by the intestine and to discuss the potential for positive regulation of intestine-driven cholesterol removal through the nutritional induction of pathways associated with calorie restriction.
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Affiliation(s)
- Casey J Wegner
- Department of Nutritional Sciences, University of Connecticut, 216 Advanced Technology Laboratory Building, 1392 Storrs Road, Storrs, CT 06269, USA.
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