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Wu Y, Zhang J, Wang W, Wu D, Kang Y, Fu L. MARK4 aggravates cardiac dysfunction in mice with STZ-induced diabetic cardiomyopathy by regulating ACSL4-mediated myocardial lipid metabolism. Sci Rep 2024; 14:12978. [PMID: 38839927 PMCID: PMC11153581 DOI: 10.1038/s41598-024-64006-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 06/04/2024] [Indexed: 06/07/2024] Open
Abstract
Diabetic cardiomyopathy is a specific type of cardiomyopathy. In DCM, glucose uptake and utilization are impaired due to insulin deficiency or resistance, and the heart relies more heavily on fatty acid oxidation for energy, resulting in myocardial lipid toxicity-related injury. MARK4 is a member of the AMPK-related kinase family, and improves ischaemic heart failure through microtubule detyrosination. However, the role of MARK4 in cardiac regulation of metabolism is unclear. In this study, after successful establishment of a diabetic cardiomyopathy model induced by streptozotocin and a high-fat diet, MARK4 expression was found to be significantly increased in STZ-induced DCM mice. After AAV9-shMARK4 was administered through the tail vein, decreased expression of MARK4 alleviated diabetic myocardial damage, reduced oxidative stress and apoptosis, and facilitated cardiomyocyte mitochondrial fusion, and promoted myocardial lipid oxidation metabolism. In addition, through the RNA-seq analysis of differentially expressed genes, we found that MARK4 deficiency promoted lipid decomposition and oxidative metabolism by downregulating the expression of ACSL4, thus reducing myocardial lipid accumulation in the STZ-induced DCM model.
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Affiliation(s)
- Yi Wu
- Laboratory of Cardiovascular Internal Medicine Department, The First Affiliated Hospital of Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, 150001, Heilongjiang, China
| | - Jingqi Zhang
- Laboratory of Cardiovascular Internal Medicine Department, The First Affiliated Hospital of Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, 150001, Heilongjiang, China
| | - Weiyi Wang
- Laboratory of Cardiovascular Internal Medicine Department, The First Affiliated Hospital of Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, 150001, Heilongjiang, China
| | - Dongdong Wu
- The First Affiliated Hospital of Jinzhou Medical University, 157 Renmin Street, Guta District, Jinzhou, 121000, China
| | - Yang Kang
- Laboratory of Cardiovascular Internal Medicine Department, The First Affiliated Hospital of Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, 150001, Heilongjiang, China
| | - Lu Fu
- Laboratory of Cardiovascular Internal Medicine Department, The First Affiliated Hospital of Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, 150001, Heilongjiang, China.
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2
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Fauste E, Panadero MI, Pérez-Armas M, Donis C, López-Laiz P, Sevillano J, Sánchez-Alonso MG, Ramos-Álvarez MP, Otero P, Bocos C. Maternal fructose intake aggravates the harmful effects of a Western diet in rat male descendants impacting their cholesterol metabolism. Food Funct 2024; 15:6147-6163. [PMID: 38767501 DOI: 10.1039/d4fo01466a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Scope: fructose consumption from added sugars correlates with the epidemic rise in MetS and CVD. Maternal fructose intake has been described to program metabolic diseases in progeny. However, consumption of fructose-containing beverages is allowed during gestation. Cholesterol is also a well-known risk factor for CVD. Therefore, it is essential to study Western diets which combine fructose and cholesterol and how maternal fructose can influence the response of progeny to these diets. Methods and results: a high-cholesterol (2%) diet combined with liquid fructose (10%), as a model of an unhealthy Western diet, was administered to descendants from control and fructose-fed mothers. Gene (mRNA and protein) expression and plasma, fecal and tissue parameters of cholesterol metabolism were measured. Interestingly, progeny from fructose-fed dams consumed less liquid fructose and cholesterol-rich chow than males from control mothers. Moreover, descendants of fructose-fed mothers fed a Western diet showed an increased cholesterol elimination through bile and feces than males from control mothers. Despite these mitigating circumstances to develop a proatherogenic profile, the same degree of hypercholesterolemia and severity of steatosis were observed in all descendants fed a Western diet, independently of maternal intake. An increased intestinal absorption of cholesterol, synthesis, esterification, and assembly into lipoprotein found in males from fructose-fed dams consuming a Western diet could be the cause. Moreover, an augmented GLP2 signalling seen in these animals would explain this enhanced lipid absorption. Conclusions: maternal fructose intake, through a fetal programming, makes a Western diet considerably more harmful in their descendants than in the offspring from control mothers.
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Affiliation(s)
- E Fauste
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - M I Panadero
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - M Pérez-Armas
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - C Donis
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - P López-Laiz
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - J Sevillano
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - M G Sánchez-Alonso
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - M P Ramos-Álvarez
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - P Otero
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
| | - C Bocos
- Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Montepríncipe, Boadilla del Monte, Madrid, Spain.
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3
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Cai Y, Yang Q, Yu Y, Yang F, Bai R, Fan X. Efficacy and underlying mechanisms of berberine against lipid metabolic diseases: a review. Front Pharmacol 2023; 14:1283784. [PMID: 38034996 PMCID: PMC10684937 DOI: 10.3389/fphar.2023.1283784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 11/03/2023] [Indexed: 12/02/2023] Open
Abstract
Lipid-lowering therapy is an important tool for the treatment of lipid metabolic diseases, which are increasing in prevalence. However, the failure of conventional lipid-lowering drugs to achieve the desired efficacy in some patients, and the side-effects of these drug regimens, highlight the urgent need for novel lipid-lowering drugs. The liver and intestine are important in the production and removal of endogenous and exogenous lipids, respectively, and have an important impact on circulating lipid levels. Elevated circulating lipids predisposes an individual to lipid deposition in the vascular wall, affecting vascular function. Berberine (BBR) modulates liver lipid production and clearance by regulating cellular targets such as cluster of differentiation 36 (CD36), acetyl-CoA carboxylase (ACC), microsomal triglyceride transfer protein (MTTP), scavenger receptor class B type 1 (SR-BI), low-density lipoprotein receptor (LDLR), and ATP-binding cassette transporter A1 (ABCA1). It influences intestinal lipid synthesis and metabolism by modulating gut microbiota composition and metabolism. Finally, BBR maintains vascular function by targeting proteins such as endothelial nitric oxide synthase (eNOS) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). This paper elucidates and summarizes the pharmacological mechanisms of berberine in lipid metabolic diseases from a multi-organ (liver, intestine, and vascular system) and multi-target perspective.
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Affiliation(s)
- Yajie Cai
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Qiaoning Yang
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- NMPA Key Laboratory for Clinical Research and Evaluation of Traditional Chinese Medicine, Beijing, China
| | - Yanqiao Yu
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Department of Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Furong Yang
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Ruina Bai
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- National Clinical Research Center for Chinese Medicine Cardiology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaodi Fan
- Institute of Basic Medical Sciences, Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, China
- Key Laboratory of Pharmacology of Chinese Materia Medica, Beijing, China
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Xu H, Xin Y, Wang J, Liu Z, Cao Y, Li W, Zhou Y, Wang Y, Liu P. The TICE Pathway: Mechanisms and Potential Clinical Applications. Curr Atheroscler Rep 2023; 25:653-662. [PMID: 37736845 DOI: 10.1007/s11883-023-01147-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2023] [Indexed: 09/23/2023]
Abstract
PURPOSE OF REVIEW Transintestinal cholesterol excretion (TICE) is a non-biliary pathway that excretes excess cholesterol from the body through feces. This article focuses on the research progress of the TICE pathway in the last few years, including the discovery process of the TICE pathway, its molecular mechanism, and potential clinical applications. RECENT FINDINGS Cholesterol homeostasis is vital for cardiovascular diseases, stroke, and neurodegenerative diseases. Beyond the cholesterol excretion via hepatobiliary pathway, TICE contributes significantly to reverse cholesterol transport ex vivo and in vivo. Nuclear receptors are ligand-activated transcription factors that regulate cholesterol metabolism. The farnesoid X receptor (FXR) and liver X receptor (LXR) activated, respectively, by oxysterols and bile acids promote intestinal cholesterol secretion through ABCG5/G8. Nutrient regulators and intestinal flora also modulate cholesterol secretion through the TICE pathway. TICE allows direct elimination of plasma cholesterol, which may provide an attractive therapeutic targets. TICE pathway may provide a potential target to stimulate cholesterol elimination and reduce the risk of cardiovascular diseases.
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Affiliation(s)
- Huimin Xu
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Yiyang Xin
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Jiaxin Wang
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Zixin Liu
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Yutong Cao
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China
| | - Weiguo Li
- People's Hospital of Hebi, Henan University, Henan, China
| | - Yun Zhou
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Basic Medical Sciences, Henan University, Henan, China.
| | - Yandong Wang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China.
| | - Peng Liu
- People's Hospital of Hebi, Henan University, Henan, China.
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5
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Cao D, Khan Z, Li X, Saito S, Bernstein EA, Victor AR, Ahmed F, Hoshi AO, Veiras LC, Shibata T, Che M, Cai L, Yamashita M, Temel RE, Giani JF, Luthringer DJ, Divakaruni AS, Okwan-Duodu D, Bernstein KE. Macrophage angiotensin-converting enzyme reduces atherosclerosis by increasing peroxisome proliferator-activated receptor α and fundamentally changing lipid metabolism. Cardiovasc Res 2023; 119:1825-1841. [PMID: 37225143 PMCID: PMC10681664 DOI: 10.1093/cvr/cvad082] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/21/2023] [Accepted: 04/05/2023] [Indexed: 05/26/2023] Open
Abstract
AIMS The metabolic failure of macrophages to adequately process lipid is central to the aetiology of atherosclerosis. Here, we examine the role of macrophage angiotensin-converting enzyme (ACE) in a mouse model of PCSK9-induced atherosclerosis. METHODS AND RESULTS Atherosclerosis in mice was induced with AAV-PCSK9 and a high-fat diet. Animals with increased macrophage ACE (ACE 10/10 mice) have a marked reduction in atherosclerosis vs. WT mice. Macrophages from both the aorta and peritoneum of ACE 10/10 express increased PPARα and have a profoundly altered phenotype to process lipids characterized by higher levels of the surface scavenger receptor CD36, increased uptake of lipid, increased capacity to transport long chain fatty acids into mitochondria, higher oxidative metabolism and lipid β-oxidation as determined using 13C isotope tracing, increased cell ATP, increased capacity for efferocytosis, increased concentrations of the lipid transporters ABCA1 and ABCG1, and increased cholesterol efflux. These effects are mostly independent of angiotensin II. Human THP-1 cells, when modified to express more ACE, increase expression of PPARα, increase cell ATP and acetyl-CoA, and increase cell efferocytosis. CONCLUSION Increased macrophage ACE expression enhances macrophage lipid metabolism, cholesterol efflux, efferocytosis, and it reduces atherosclerosis. This has implications for the treatment of cardiovascular disease with angiotensin II receptor antagonists vs. ACE inhibitors.
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Affiliation(s)
- DuoYao Cao
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Zakir Khan
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Xiaomo Li
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Suguru Saito
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Ellen A Bernstein
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Aaron R Victor
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Faizan Ahmed
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Aoi O Hoshi
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Luciana C Veiras
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Tomohiro Shibata
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Mingtian Che
- Biobank and Pathology Shared Resource, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Lei Cai
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | - Michifumi Yamashita
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | - Ryan E Temel
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | - Jorge F Giani
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Daniel J Luthringer
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Derick Okwan-Duodu
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Kenneth E Bernstein
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
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6
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Truong JK, Li J, Li Q, Pachura K, Rao A, Gumber S, Fuchs CD, Feranchak AP, Karpen SJ, Trauner M, Dawson PA. Active enterohepatic cycling is not required for the choleretic actions of 24-norUrsodeoxycholic acid in mice. JCI Insight 2023; 8:e149360. [PMID: 36787187 PMCID: PMC10070106 DOI: 10.1172/jci.insight.149360] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 02/07/2023] [Indexed: 02/15/2023] Open
Abstract
The pronounced choleretic properties of 24-norUrsodeoxycholic acid (norUDCA) to induce bicarbonate-rich bile secretion have been attributed to its ability to undergo cholehepatic shunting. The goal of this study was to identify the mechanisms underlying the choleretic actions of norUDCA and the role of the bile acid transporters. Here, we show that the apical sodium-dependent bile acid transporter (ASBT), organic solute transporter-α (OSTα), and organic anion transporting polypeptide 1a/1b (OATP1a/1b) transporters are dispensable for the norUDCA stimulation of bile flow and biliary bicarbonate secretion. Chloride channels in biliary epithelial cells provide the driving force for biliary secretion. In mouse large cholangiocytes, norUDCA potently stimulated chloride currents that were blocked by siRNA silencing and pharmacological inhibition of calcium-activated chloride channel transmembrane member 16A (TMEM16A) but unaffected by ASBT inhibition. In agreement, blocking intestinal bile acid reabsorption by coadministration of an ASBT inhibitor or bile acid sequestrant did not impact norUDCA stimulation of bile flow in WT mice. The results indicate that these major bile acid transporters are not directly involved in the absorption, cholehepatic shunting, or choleretic actions of norUDCA. Additionally, the findings support further investigation of the therapeutic synergy between norUDCA and ASBT inhibitors or bile acid sequestrants for cholestatic liver disease.
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Affiliation(s)
- Jennifer K. Truong
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Jianing Li
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Qin Li
- Department of Pediatrics, University of Pittsburgh Medical Center Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kimberly Pachura
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Anuradha Rao
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Sanjeev Gumber
- Division of Pathology and Laboratory Medicine, Yerkes National Research Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Claudia Daniela Fuchs
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Andrew P. Feranchak
- Department of Pediatrics, University of Pittsburgh Medical Center Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Saul J. Karpen
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Paul A. Dawson
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
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7
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Semova I, Levenson AE, Krawczyk J, Bullock K, Gearing ME, Ling AV, Williams KA, Miao J, Adamson SS, Shin DJ, Chahar S, Graham MJ, Crooke RM, Hagey LR, Vicent D, de Ferranti SD, Kidambi S, Clish CB, Biddinger SB. Insulin Prevents Hypercholesterolemia by Suppressing 12a-Hydroxylated Bile Acid Production. Circulation 2022; 145:969-982. [PMID: 35193378 PMCID: PMC9365453 DOI: 10.1161/circulationaha.120.045373] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: The risk of cardiovascular disease in type 1 diabetes remains extremely high, despite marked advances in blood glucose control and even the widespread use of cholesterol synthesis inhibitors. Thus, a deeper understanding of insulin regulation of cholesterol metabolism, and its disruption in type 1 diabetes, could reveal better treatment strategies. Methods: To define the mechanisms by which insulin controls plasma cholesterol levels, we knocked down the insulin receptor, FoxO1, and the key bile acid synthesis enzyme, CYP8B1. We measured bile acid composition, cholesterol absorption, and plasma cholesterol. In parallel, we measured markers of cholesterol absorption and synthesis in humans with type 1 diabetes treated with ezetimibe and statins in a double-blind crossover study. Results: Mice with hepatic deletion of the insulin receptor showed marked increases in 12α-hydroxylated bile acids (12HBAs), cholesterol absorption, and plasma cholesterol. This phenotype was entirely reversed by hepatic deletion of FoxO1. FoxO1 is inhibited by insulin, and required for the production of 12HBAs, which promote intestinal cholesterol absorption and suppress hepatic cholesterol synthesis. Knockdown of Cyp8b1 normalized 12HBA levels and completely prevented hypercholesterolemia in mice with hepatic deletion of the insulin receptor (n=5-30) as well as mouse models of type 1 diabetes (n=5-22). In parallel, the cholesterol absorption inhibitor, ezetimibe, normalized cholesterol absorption and LDL-cholesterol in patients with type 1 diabetes as well as, or better than, the cholesterol synthesis inhibitor, simvastatin (n=20). Conclusions: Insulin, by inhibiting FoxO1 in the liver, reduces 12HBAs, cholesterol absorption, and plasma cholesterol levels. Thus, type 1 diabetes leads to a unique set of derangements in cholesterol metabolism, with increased absorption rather than synthesis. These derangements are reversed by ezetimibe, but not statins, which are currently the first line of lipid-lowering treatment in type 1 diabetes. Taken together, these data suggest that a personalized approach to lipid lowering in type 1 diabetes may be more effective and highlight the need for further studies specifically in this group of patients.
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Affiliation(s)
- Ivana Semova
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Amy E Levenson
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Joanna Krawczyk
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | - Mary E Gearing
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Alisha V Ling
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Kathryn A Williams
- Biostatistics and Research Design Center, ICCTR, Boston Children's Hospital, Boston, MA
| | - Ji Miao
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Stuart S Adamson
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Dong-Ju Shin
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Satyapal Chahar
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | | | - Lee R Hagey
- Department of Medicine, University of California, San Diego, CA
| | - David Vicent
- Instituto de Investigación Sanitaria del Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
| | - Sarah D de Ferranti
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Srividya Kidambi
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI
| | | | - Sudha B Biddinger
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA
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8
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Gora AH, Rehman S, Kiron V, Dias J, Fernandes JMO, Olsvik PA, Siriyappagouder P, Vatsos I, Schmid-Staiger U, Frick K, Cardoso M. Management of Hypercholesterolemia Through Dietary ß-glucans–Insights From a Zebrafish Model. Front Nutr 2022; 8:797452. [PMID: 35096942 PMCID: PMC8790573 DOI: 10.3389/fnut.2021.797452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/09/2021] [Indexed: 11/20/2022] Open
Abstract
Consumption of lipid-rich foods can increase the blood cholesterol content. β-glucans have hypocholesterolemic effect. However, subtle changes in their molecular branching can influence bioactivity. Therefore, a comparative investigation of the cholesterol-lowering potential of two β-glucans with different branching patterns and a cholesterol-lowering drug, namely simvastatin was undertaken employing the zebrafish (Danio rerio) model of diet-induced hypercholesterolemia. Fish were allocated to 5 dietary treatments; a control group, a high cholesterol group, two β-glucan groups, and a simvastatin group. We investigated plasma total cholesterol, LDL and HDL cholesterol levels, histological changes in the tissues, and explored intestinal transcriptomic changes induced by the experimental diets. Dietary cholesterol likely caused the suppression of endogenous cholesterol biosynthesis, induced dysfunction of endoplasmic reticulum and mitochondria, and altered the histomorphology of the intestine. The two β-glucans and simvastatin significantly abated the rise in plasma cholesterol levels and restored the expression of specific genes to alleviate the endoplasmic reticulum-related effects induced by the dietary cholesterol. Furthermore, the distinct patterns of transcriptomic changes in the intestine elicited by the oat and microalga β-glucans impacted processes such as fatty acid metabolism, protein catabolic processes, and nuclear division. Oat and microalgal β-glucans also altered the pattern of lipid deposition in the liver. Our study provides insights into the effectiveness of different β-glucans to alleviate dysfunctions in lipid metabolism caused by dietary cholesterol.
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Affiliation(s)
| | - Saima Rehman
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Viswanath Kiron
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
- *Correspondence: Viswanath Kiron
| | | | | | - Pål Asgeir Olsvik
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | | | - Ioannis Vatsos
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Ulrike Schmid-Staiger
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Innovation Field Algae Biotechnology-Development, Stuttgart, Germany
| | - Konstantin Frick
- Institute of Interfacial Process Engineering and Plasma Technology, University of Stuttgart, Stuttgart, Germany
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9
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Yu XC, Fu Y, Bi YH, Zhang WW, Li J, Ji T, Chao Y, Meng QH, Chen Q, Ma MH, Zhang YH, Shan J, Bian HM. Alisol B 23-acetate activates ABCG5/G8 in the jejunum via the LXRα/ACAT2 pathway to relieve atherosclerosis in ovariectomized ApoE -/- mice. Aging (Albany NY) 2020; 12:25744-25766. [PMID: 33234731 PMCID: PMC7803561 DOI: 10.18632/aging.104185] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 10/06/2020] [Indexed: 12/20/2022]
Abstract
Phytosterols have been shown to improve blood lipid levels and treat atherosclerosis. This research investigated the effects of phytosterol Alisol B 23-acetate (AB23A) on jejunum lipid metabolism and atherosclerosis. The results show that intragastric administration of AB23A can significantly reduce atherosclerotic plaque area and lipid accumulation in the jejunum of ovariectomized ApoE-/- mice fed a high-fat diet and can also improve the lipid mass spectra of the plasma and jejunum. In vitro studies have shown that AB23A can increase cholesterol outflow in Caco-2 cells exposed to high fat concentrations and increase the expression of ATP-binding cassette transfer proteins G5/G8 (ABCG5/G8), the liver X receptor α (LXRα). Furthermore, inhibition of LXRα can significantly eliminate the active effect of AB23A on decreasing intracellular lipid accumulation. We also confirmed that AB23A has a negative effect on Acyl-CoA cholesterol acyltransferase 2 (ACAT2) in Caco-2 cells cultured in the high concentrations of fat, and we found that AB23A further reduces ACAT2 expression in cells treated with the ACAT2 inhibitor pyripyropene or transfected with ACAT2 siRNA. In conclusion, we confirmed that AB23A can reduce the absorption of dietary lipids in the jejunum by affecting the LXRα-ACAT2-ABCG5/G8 pathway and ultimately exert an anti-atherosclerotic effect.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily G, Member 5/drug effects
- ATP Binding Cassette Transporter, Subfamily G, Member 5/metabolism
- ATP Binding Cassette Transporter, Subfamily G, Member 8/drug effects
- ATP Binding Cassette Transporter, Subfamily G, Member 8/metabolism
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Aorta/pathology
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Caco-2 Cells
- Cholestenones/pharmacology
- Cholesterol/metabolism
- Cholesterol Esters/metabolism
- Diet, High-Fat
- Female
- Glycerophospholipids/metabolism
- Humans
- Jejunum/drug effects
- Jejunum/metabolism
- Jejunum/pathology
- Lipid Droplets/drug effects
- Lipid Droplets/metabolism
- Lipid Droplets/pathology
- Lipid Metabolism/drug effects
- Lipoproteins/drug effects
- Lipoproteins/metabolism
- Liver X Receptors/drug effects
- Liver X Receptors/metabolism
- Mice
- Mice, Knockout, ApoE
- Ovariectomy
- Plaque, Atherosclerotic/metabolism
- Plaque, Atherosclerotic/pathology
- Sterol O-Acyltransferase/drug effects
- Sterol O-Acyltransferase/metabolism
- Triglycerides/metabolism
- Sterol O-Acyltransferase 2
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Affiliation(s)
- Xi-Chao Yu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yu Fu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yun-Hui Bi
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Wei-Wei Zhang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jun Li
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Tingting Ji
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Ying Chao
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Qing-Hai Meng
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Qi Chen
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Meng-Hua Ma
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yu-Han Zhang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jinjun Shan
- Institute of Pediatrics, Jiangsu Key Laboratory of Pediatric Respiratory Disease, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Medical Metabolomics Center, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Hui-Min Bian
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- National Standard Laboratory of Pharmacology of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Key Laboratory of Therapeutic Material of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
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10
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Morgan AE, Mc Auley MT. Cholesterol Homeostasis: An In Silico Investigation into How Aging Disrupts Its Key Hepatic Regulatory Mechanisms. BIOLOGY 2020; 9:E314. [PMID: 33007859 PMCID: PMC7599957 DOI: 10.3390/biology9100314] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/21/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022]
Abstract
The dysregulation of intracellular cholesterol homeostasis is associated with several age-related diseases, most notably cardiovascular disease (CVD). Research in this area has benefitted from using computational modelling to study the inherent complexity associated with the regulation of this system. In addition to facilitating hypothesis exploration, the utility of modelling lies in its ability to represent an array of rate limiting enzymatic reactions, together with multiple feedback loops, which collectively define the dynamics of cholesterol homeostasis. However, to date no model has specifically investigated the effects aging has on this system. This work addresses this shortcoming by explicitly focusing on the impact of aging on hepatic intracellular cholesterol homeostasis. The model was used to investigate the experimental findings that reactive oxygen species induce the total activation of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR). Moreover, the model explored the impact of an age-related decrease in hepatic acetyl-CoA acetyltransferase 2 (ACAT2). The model suggested that an increase in the activity of HMGCR does not have as significant an impact on cholesterol homeostasis as a decrease in hepatic ACAT2 activity. According to the model, a decrease in the activity of hepatic ACAT2 raises free cholesterol (FC) and decreases low-density lipoprotein cholesterol (LDL-C) levels. Increased acetyl CoA synthesis resulted in a reduction in the number of hepatic low-density lipoprotein receptors, and increased LDL-C, FC, and cholesterol esters. The rise in LDL-C was restricted by elevated hepatic FC accumulation. Taken together these findings have important implications for healthspan. This is because emerging clinical data suggest hepatic FC accumulation is relevant to the pathogenesis of non-alcoholic fatty liver disease (NAFLD), which is associated with an increased risk of CVD. These pathophysiological changes could, in part, help to explain the phenomenon of increased mortality associated with low levels of LDL-C which have been observed in certain studies involving the oldest old (≥85 years).
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Affiliation(s)
| | - Mark Tomás Mc Auley
- Faculty of Science and Engineering, University of Chester, Thornton Science Park, Chester CH2 4NU, UK;
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11
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Naudin CR, Maner-Smith K, Owens JA, Wynn GM, Robinson BS, Matthews JD, Reedy AR, Luo L, Wolfarth AA, Darby TM, Ortlund EA, Jones RM. Lactococcus lactis Subspecies cremoris Elicits Protection Against Metabolic Changes Induced by a Western-Style Diet. Gastroenterology 2020; 159:639-651.e5. [PMID: 32169430 DOI: 10.1053/j.gastro.2020.03.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 02/28/2020] [Accepted: 03/03/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS A Western-style diet, which is high in fat and sugar, can cause significant dyslipidemia and nonalcoholic fatty liver disease; the diet has an especially strong effect in women, regardless of total calorie intake. Dietary supplementation with beneficial microbes might reduce the detrimental effects of a Western-style diet. We assessed the effects of Lactococcus lactis subspecies (subsp) cremoris on weight gain, liver fat, serum cholesterol, and insulin resistance in female mice on a high-fat, high-carbohydrate diet. METHODS Female C57BL/6 mice were fed either a high-fat, high-carbohydrate (Western-style) diet that contained 40% fat (mostly milk fat) and 43% carbohydrate (mostly sucrose) or a calorie-matched-per-gram control diet. The diets of mice were supplemented with 1 × 109 colony-forming units of L lactis subsp cremoris ATCC 19257 or Lactobacillus rhamnosus GG ATCC 53103 (control bacteria) 3 times per week for 16 weeks. Body weights were measured, and fecal, blood, and liver tissues were collected and analyzed. Livers were analyzed for fat accumulation and inflammation, and blood samples were analyzed for cholesterol and glucose levels. Mice were housed within Comprehensive Lab Animal Monitoring System cages, and respiratory exchange ratio and activity were measured. Hepatic lipid profiles of L lactis subsp cremoris-supplemented mice were characterized by lipidomics mass spectrometry analysis. RESULTS Mice fed L lactis subsp cremoris while on the Western-style diet gained less weight, developed less hepatic steatosis and inflammation, and had a lower mean serum level of cholesterol and body mass index than mice fed the control bacteria. Mice fed the L lactis subsp cremoris had increased glucose tolerance while on the Western-style diet compared to mice fed control bacteria and had alterations in hepatic lipids, including oxylipins. CONCLUSIONS Dietary supplementation with L lactis subsp cremoris in female mice on a high-fat, high-carbohydrate (Western-style) diet caused them to gain less weight, develop less liver fat and inflammation, reduce serum cholesterol levels, and increase glucose tolerance compared with mice on the same diet fed control bacteria. L lactis subsp cremoris is safe for oral ingestion and might be developed for persons with metabolic and liver disorders caused by a Western-style diet.
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Affiliation(s)
- Crystal R Naudin
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Kristal Maner-Smith
- Emory Integrated Metabolomics and Lipidomics Core, Emory University, Atlanta, Georgia
| | - Joshua A Owens
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Grace M Wynn
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Brian S Robinson
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia
| | - Jason D Matthews
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia
| | - April R Reedy
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia
| | - Liping Luo
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Alexandra A Wolfarth
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia
| | - Trevor M Darby
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Eric A Ortlund
- Department of Biochemistry, Emory University, Atlanta, Georgia, United States of America
| | - Rheinallt M Jones
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Emory University, Atlanta, Georgia.
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12
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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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13
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Pramfalk C, Jakobsson T, Verzijl CRC, Minniti ME, Obensa C, Ripamonti F, Olin M, Pedrelli M, Eriksson M, Parini P. Generation of new hepatocyte-like in vitro models better resembling human lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158659. [PMID: 32058035 DOI: 10.1016/j.bbalip.2020.158659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/03/2020] [Accepted: 02/07/2020] [Indexed: 11/21/2022]
Abstract
In contrast to human hepatocytes in vivo, which solely express acyl-coenzyme A:cholesterol acyltransferase (ACAT) 2, both ACAT1 and ACAT2 (encoded by SOAT1 and SOAT2) are expressed in primary human hepatocytes and in human hepatoma cell lines. Here, we aimed to create hepatocyte-like cells expressing the ACAT2, but not the ACAT1, protein to generate a model that - at least in this regard - resembles the human condition in vivo and to assess the effects on lipid metabolism. Using the Clustered Regularly Interspaced Short Palindromic Repeats technology, we knocked out SOAT1 in HepG2 and Huh7.5 cells. The wild type and SOAT2-only-cells were cultured with fetal bovine or human serum and the effects on lipoprotein and lipid metabolism were studied. In SOAT2-only-HepG2 cells, increased levels of cholesterol, triglycerides, apolipoprotein B and lipoprotein(a) in the cell media were detected; this was likely dependent of the increased expression of key genes involved in lipid metabolism (e.g. MTP, APOB, HMGCR, LDLR, ACACA, and DGAT2). Opposite effects were observed in SOAT2-only-Huh7.5 cells. Our study shows that the expression of SOAT1 in hepatocyte-like cells contributes to the distorted phenotype observed in HepG2 and Huh7.5 cells. As not only parameters of lipoprotein and lipid metabolism but also some markers of differentiation/maturation increase in the SOAT2-only-HepG2 cells cultured with HS, this cellular model represent an improved model for studies of lipid metabolism.
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Affiliation(s)
- Camilla Pramfalk
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden; Patient Area Nephrology and Endocrinology, Inflammation and Infection Theme, Karolinska University Hospital, Stockholm, Sweden
| | - Tomas Jakobsson
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Cristy R C Verzijl
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Mirko E Minniti
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Clara Obensa
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Federico Ripamonti
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Maria Olin
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Matteo Pedrelli
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Mats Eriksson
- Patient Area Nephrology and Endocrinology, Inflammation and Infection Theme, Karolinska University Hospital, Stockholm, Sweden; Metabolism Unit, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Paolo Parini
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden; Patient Area Nephrology and Endocrinology, Inflammation and Infection Theme, Karolinska University Hospital, Stockholm, Sweden; Metabolism Unit, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.
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14
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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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15
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Mechanisms and regulation of cholesterol homeostasis. Nat Rev Mol Cell Biol 2019; 21:225-245. [DOI: 10.1038/s41580-019-0190-7] [Citation(s) in RCA: 450] [Impact Index Per Article: 90.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2019] [Indexed: 12/14/2022]
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16
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miR-146a Deficiency Accelerates Hepatic Inflammation Without Influencing Diet-induced Obesity in Mice. Sci Rep 2019; 9:12626. [PMID: 31477775 PMCID: PMC6718417 DOI: 10.1038/s41598-019-49090-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 08/20/2019] [Indexed: 02/06/2023] Open
Abstract
miR-146a, an anti-inflammatory microRNA, is shown to be a negative regulator of adipocyte inflammation. However, the functional contribution of miR-146a in the development of obesity is not defined. In order to determine whether miR-146a influences diet-induced obesity, mice that were either wild type (WT) or miR-146a deficient (KO) were fed with high (60% kcal) fat diet (HFD) for 16 weeks. Deficiency of miR-146a did not influence obesity measured as HFD-induced body weight and fat mass gain, or metabolism of glucose and insulin tolerance. In addition, adipocyte apoptosis, adipose tissue collagen and macrophage accumulation as detected by TUNEL, Picro Sirius and F4/80 immunostaining, respectively, were comparable between the two groups of mice. Although, miR-146a deficiency had no influence on HFD-induced hepatic lipid accumulation, interestingly, it significantly increased obesity-induced inflammatory responses in liver tissue. The present study demonstrates that miR-146a deficiency had no influence on the development of HFD-induced obesity and adipose tissue remodeling, whereas it significantly increased hepatic inflammation in obese mice. This result suggests that miR-146a regulates hepatic inflammation during development of obesity.
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17
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Kim S, Graham MJ, Lee RG, Yang L, Kim S, Subramanian V, Layne JD, Cai L, Temel RE, Shih D, Lusis AJ, Berliner JA, Lee S. Heparin-binding EGF-like growth factor (HB-EGF) antisense oligonucleotide protected against hyperlipidemia-associated atherosclerosis. Nutr Metab Cardiovasc Dis 2019; 29:306-315. [PMID: 30738642 PMCID: PMC6452438 DOI: 10.1016/j.numecd.2018.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 11/24/2018] [Accepted: 12/27/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND AIMS Heparin-binding EGF-like growth factor (HB-EGF) is a representative EGF family member that interacts with EGFR under diverse stress environment. Previously, we reported that the HB-EGF-targeting using antisense oligonucleotide (ASO) effectively suppressed an aortic aneurysm in the vessel wall and circulatory lipid levels. In this study, we further examined the effects of the HB-EGF ASO administration on the development of hyperlipidemia-associated atherosclerosis using an atherogenic mouse model. METHODS AND RESULTS The male and female LDLR deficient mice under Western diet containing 21% fat and 0.2% cholesterol content were cotreated with control and HB-EGF ASOs for 12 weeks. We observed that the HB-EGF ASO administration effectively downregulated circulatory VLDL- and LDL-associated lipid levels in circulation; concordantly, the HB-EGF targeting effectively suppressed the development of atherosclerosis in the aorta. An EGFR blocker BIBX1382 administration suppressed the hepatic TG secretion rate, suggesting a positive role of the HB-EGF signaling for the hepatic VLDL production. We newly observed that there was a significant improvement of the insulin sensitivity by the HB-EGF ASO administration in a mouse model under the Western diet as demonstrated by the improvement of the glucose and insulin tolerances. CONCLUSION The HB-EGF ASO administration effectively downregulated circulatory lipid levels by suppressing hepatic VLDL production rate, which leads to effective protection against atherosclerosis in the vascular wall.
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Affiliation(s)
- S Kim
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - M J Graham
- Cardiovascular Antisense Drug Discovery Group, Ionis Pharmaceuticals, Carlsbad, CA, 92010, USA
| | - R G Lee
- Cardiovascular Antisense Drug Discovery Group, Ionis Pharmaceuticals, Carlsbad, CA, 92010, USA
| | - L Yang
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - S Kim
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - V Subramanian
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - J D Layne
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - L Cai
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - R E Temel
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY, 40536, USA
| | - D Shih
- Department of Medicine-Cardiology, University of California-Los Angeles (UCLA) School of Medicine, Los Angeles, CA, 90095, USA
| | - A J Lusis
- Department of Medicine-Cardiology, University of California-Los Angeles (UCLA) School of Medicine, Los Angeles, CA, 90095, USA; Department of Human Genetics, University of California-Los Angeles (UCLA) School of Medicine, Los Angeles, CA, 90095, USA; Department of Microbiology, Immunology & Molecular Genetics, University of California-Los Angeles (UCLA), Los Angeles, CA, 90095, USA
| | - J A Berliner
- Department of Pathology and Laboratory Medicine, University of California-Los Angeles (UCLA), Los Angeles, CA, 90095, USA
| | - S Lee
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA; Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, 40536, USA.
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18
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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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19
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Brandt EJ, Benes LB, Lee L, Dayspring TD, Sorrentino M, Davidson M. The Effect of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibition on Sterol Absorption Markers in a Cohort of Real-World Patients. J Cardiovasc Pharmacol Ther 2018; 24:54-61. [DOI: 10.1177/1074248418780733] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Background: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is expressed in multiple tissues, including the small intestine. The effect of PCSK9 inhibition on cholesterol absorption is not known. Objectives: Measure serum cholesterol absorption markers before and after initiation of PCSK9 inhibitors. Methods: Single-center retrospective cohort of patients administered evolocumab and alirocumab between July 2015 and January 2017. Paired t tests were used to compare mean serum cholesterol marker concentrations, and ratios to total cholesterol, before and after PCSK9 inhibitor initiation. Analyses were repeated for those taking and not taking statins and taking or not taking ezetimibe at both initiation and follow-up, for each PCSK9 inhibitor, and based on follow-up time (<60, 60-120, and >120 days). Results: There were 62 possible participants, 34 were excluded for lack of data or unknown PCSK9 inhibitor initiation date. Average follow-up was 92.5 days. Mean campesterol (before 3.14 μg/mL, 95% CI: 2.79-4.38 μg/mL; after 2.09 μg/mL, 95% CI: 1.87-2.31 μg/mL; P < .0001), sitosterol (before 2.46 μg/mL, 95% CI: 2.23-2.70 μg/mL; after 1.62 μg/mL, 95% CI: 1.48-1.75 μg/mL; P < .0001), and cholestanol (before 3.25 μg/mL, 95% CI: 3.04-3.47 μg/mL; after 2.08 μg/mL, 95% CI: 1.96-2.21 μg/mL; P < .0001) all significantly decreased at follow-up. There was no significant change in absorption marker to total cholesterol ratios. Findings were not influenced by statin or ezetimibe use or nonuse, which PCSK9 inhibitor was prescribed, or time to follow-up. Conclusion: Proprotein convertase subtilisin/kexin type 9 inhibition was associated with decreased cholesterol absorption markers.
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Affiliation(s)
- Eric J. Brandt
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Lane B. Benes
- Division of Cardiology, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Linda Lee
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | | | - Matthew Sorrentino
- Division of Cardiology, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Michael Davidson
- Division of Cardiology, Department of Medicine, University of Chicago, Chicago, IL, USA
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20
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Wang Y, Tang W, Yang P, Shin H, Li Q. Hepatic NPC1L1 promotes hyperlipidemia in LDL receptor deficient mice. Biochem Biophys Res Commun 2018; 499:626-633. [DOI: 10.1016/j.bbrc.2018.03.200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
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21
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Long-term Western diet fed apolipoprotein E-deficient rats exhibit only modest early atherosclerotic characteristics. Sci Rep 2018; 8:5416. [PMID: 29615808 PMCID: PMC5882891 DOI: 10.1038/s41598-018-23835-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 03/22/2018] [Indexed: 12/16/2022] Open
Abstract
In the apolipoprotein E–deficient mouse, the gut microbiota has an impact on the development of atherosclerosis, but whether such correlations are also present in rats requires investigation. Therefore, we studied female SD-Apoetm1sage (Apoe−/−) rats fed either a Western diet or a low-fat control diet with or without gluten, which is known to promote gut microbiota changes, until 20 weeks of age. We hypothesized that the manifestation of atherosclerosis would be more severe in Apoe−/− rats fed the Western high-fat diet, as compared with rats fed the low-fat diet, and that atherosclerosis would be accelerated by gluten. Both Western diet-feeding and gluten resulted in significant changes in gut microbiota, but the microbiota impact of gluten was transient. Compared with Apoe−/− rats fed a low-fat diet, Western diet-fed Apoe−/− rats were heavier and became glucose intolerant with increased levels of oxidative stress. They developed early fatty streak lesions in their aortic sinus, while there was no evidence of atherosclerosis in the thoracic aorta. No conclusions could be made on the impact of gluten on atherosclerosis. Although Western diet-fed Apoe−/− rats exhibited a more human-like LDL dominated blood lipid profile, signs of obesity, type 2 diabetes and cardiovascular disease were modest.
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22
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Kim S, Yang L, Kim S, Lee RG, Graham MJ, Berliner JA, Lusis AJ, Cai L, Temel RE, Rateri DL, Lee S. Targeting hepatic heparin-binding EGF-like growth factor (HB-EGF) induces anti-hyperlipidemia leading to reduction of angiotensin II-induced aneurysm development. PLoS One 2017; 12:e0182566. [PMID: 28792970 PMCID: PMC5549937 DOI: 10.1371/journal.pone.0182566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/20/2017] [Indexed: 01/02/2023] Open
Abstract
Objective The upregulated expression of heparin binding EGF-like growth factor (HB-EGF) in the vessel and circulation is associated with risk of cardiovascular disease. In this study, we tested the effects of HB-EGF targeting using HB-EGF-specific antisense oligonucleotide (ASO) on the development of aortic aneurysm in a mouse aneurysm model. Approach and results Low-density lipoprotein receptor (LDLR) deficient mice (male, 16 weeks of age) were injected with control and HB-EGF ASOs for 10 weeks. To induce aneurysm, the mice were fed a high fat diet (22% fat, 0.2% cholesterol; w/w) at 5 week point of ASO administration and infused with angiotensin II (AngII, 1,000ng/kg/min) for the last 4 weeks of ASO administration. We confirmed that the HB-EGF ASO administration significantly downregulated HB-EGF expression in multiple tissues including the liver. Importantly, the HB-EGF ASO administration significantly suppressed development of aortic aneurysms including thoracic and abdominal types. Interestingly, the HB-EGF ASO administration induced a remarkable anti-hyperlipidemic effect by suppressing very low density lipoprotein (VLDL) level in the blood. Mechanistically, the HB-EGF targeting suppressed hepatic VLDL secretion rate without changing heparin-releasable plasma triglyceride (TG) hydrolytic activity or fecal neutral cholesterol excretion rate. Conclusion This result suggested that the HB-EGF targeting induced protection against aneurysm development through anti-hyperlipidemic effects. Suppression of hepatic VLDL production process appears to be a key mechanism for the anti-hyperlipidemic effects by the HB-EGF targeting.
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Affiliation(s)
- Seonwook Kim
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Lihua Yang
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Seongu Kim
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Richard G. Lee
- Cardiovascular Antisense Drug Discovery Group at the Ionis Pharmaceuticals, Inc., Carlsbad, California, United States of America
| | - Mark J. Graham
- Cardiovascular Antisense Drug Discovery Group at the Ionis Pharmaceuticals, Inc., Carlsbad, California, United States of America
| | - Judith A. Berliner
- Department of Medicine-Cardiology, University of California-Los Angeles School of Medicine, Los Angeles, California, United States of America
| | - Aldons J. Lusis
- Department of Medicine-Cardiology, University of California-Los Angeles School of Medicine, Los Angeles, California, United States of America
| | - Lei Cai
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Ryan E. Temel
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- Department of Pharmacology & Nutritional Sciences at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Debra L. Rateri
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Sangderk Lee
- Saha Cardiovascular Research Center at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- Department of Pharmacology & Nutritional Sciences at the University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- * E-mail:
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23
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Ferguson D, Zhang J, Davis MA, Helsley RN, Vedin LL, Lee RG, Crooke RM, Graham MJ, Allende DS, Parini P, Brown JM. The lipid droplet-associated protein perilipin 3 facilitates hepatitis C virus-driven hepatic steatosis. J Lipid Res 2016; 58:420-432. [PMID: 27941027 DOI: 10.1194/jlr.m073734] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Indexed: 12/18/2022] Open
Abstract
Hepatitis C virus (HCV) is an enveloped RNA virus responsible for 170 million cases of viral hepatitis worldwide. Over 50% of chronically infected HCV patients develop hepatic steatosis, and steatosis can be induced by expression of HCV core protein (core) alone. Additionally, core must associate with cytoplasmic lipid droplets (LDs) for steatosis development and viral particle assembly. Due to the importance of the LD as a key component of hepatic lipid storage and as a platform for HCV particle assembly, it seems this dynamic subcellular organelle is a gatekeeper in the pathogenesis of viral hepatitis. Here, we hypothesized that core requires the host LD scaffold protein, perilipin (PLIN)3, to induce hepatic steatosis. To test our hypothesis in vivo, we have studied core-induced hepatic steatosis in the absence or presence of antisense oligonucleotide-mediated knockdown of PLIN3. PLIN3 knockdown blunted HCV core-induced steatosis in transgenic mice fed either chow or a moderate fat diet. Collectively, our studies demonstrate that the LD scaffold protein, PLIN3, is essential for HCV core-induced hepatic steatosis and provide new insights into the pathogenesis of HCV.
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Affiliation(s)
- Daniel Ferguson
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH.,Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Jun Zhang
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Matthew A Davis
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Robert N Helsley
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Lise-Lotte Vedin
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Richard G Lee
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Rosanne M Crooke
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Mark J Graham
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | | | - Paolo Parini
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
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24
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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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25
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Wang B, Rong X, Duerr MA, Hermanson DJ, Hedde PN, Wong JS, Vallim TQDA, Cravatt BF, Gratton E, Ford DA, Tontonoz P. Intestinal Phospholipid Remodeling Is Required for Dietary-Lipid Uptake and Survival on a High-Fat Diet. Cell Metab 2016; 23:492-504. [PMID: 26833026 PMCID: PMC4785086 DOI: 10.1016/j.cmet.2016.01.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/02/2015] [Accepted: 12/30/2015] [Indexed: 01/31/2023]
Abstract
Phospholipids are important determinants of membrane biophysical properties, but the impact of membrane acyl chain composition on dietary-lipid absorption is unknown. Here we demonstrate that the LXR-responsive phospholipid-remodeling enzyme Lpcat3 modulates intestinal fatty acid and cholesterol absorption and is required for survival on a high-fat diet. Mice lacking Lpcat3 in the intestine thrive on carbohydrate-based chow but lose body weight rapidly and become moribund on a triglyceride-rich diet. Lpcat3-dependent incorporation of polyunsaturated fatty acids into phospholipids is required for the efficient transport of dietary lipids into enterocytes. Furthermore, loss of Lpcat3 amplifies the production of gut hormones, including GLP-1 and oleoylethanolamide, in response to high-fat feeding, contributing to the paradoxical cessation of food intake in the setting of starvation. These results reveal that membrane phospholipid composition is a gating factor in passive lipid absorption and implicate LXR-Lpcat3 signaling in a gut-brain feedback loop that couples absorption to food intake.
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Affiliation(s)
- Bo Wang
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xin Rong
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mark A Duerr
- Department of Biochemistry and Molecular Biology, Center for Cardiovascular Research, Saint Louis University, St. Louis, MO 63104, USA
| | - Daniel J Hermanson
- Department of Chemical Physiology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Per Niklas Hedde
- Laboratory of Fluorescence Dynamics, Biomedical Engineering Department, University of California, Irvine, Irvine, CA 92697, USA; Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
| | - Jinny S Wong
- Electron Microscopy Core, Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA
| | - Thomas Q de Aguiar Vallim
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Benjamin F Cravatt
- Department of Chemical Physiology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Enrico Gratton
- Laboratory of Fluorescence Dynamics, Biomedical Engineering Department, University of California, Irvine, Irvine, CA 92697, USA; Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
| | - David A Ford
- Department of Biochemistry and Molecular Biology, Center for Cardiovascular Research, Saint Louis University, St. Louis, MO 63104, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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26
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Warrier M, Zhang J, Bura K, Kelley K, Wilson MD, Rudel LL, Brown JM. Sterol O-Acyltransferase 2-Driven Cholesterol Esterification Opposes Liver X Receptor-Stimulated Fecal Neutral Sterol Loss. Lipids 2016; 51:151-7. [PMID: 26729489 PMCID: PMC5221701 DOI: 10.1007/s11745-015-4116-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 12/18/2015] [Indexed: 11/28/2022]
Abstract
Statin drugs have proven a successful and relatively safe therapy for the treatment of atherosclerotic cardiovascular disease (CVD). However, even with the substantial low-density lipoprotein (LDL) cholesterol lowering achieved with statin treatment, CVD remains the top cause of death in developed countries. Selective inhibitors of the cholesterol esterifying enzyme sterol-O acyltransferase 2 (SOAT2) hold great promise as effective CVD therapeutics. In mouse models, previous work has demonstrated that either antisense oligonucleotide (ASO) or small molecule inhibitors of SOAT2 can effectively reduce CVD progression, and even promote regression of established CVD. Although it is well known that SOAT2-driven cholesterol esterification can alter both the packaging and retention of atherogenic apoB-containing lipoproteins, here we set out to determine whether SOAT2-driven cholesterol esterification can also impact basal and liver X receptor (LXR)-stimulated fecal neutral sterol loss. These studies demonstrate that SOAT2 is a negative regulator of LXR-stimulated fecal neutral sterol loss in mice.
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Affiliation(s)
- Manya Warrier
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH, 44195, USA
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Jun Zhang
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Kanwardeep Bura
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Kathryn Kelley
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Martha D Wilson
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Lawrence L Rudel
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH, 44195, USA.
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
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27
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Modulating the Gut Microbiota Improves Glucose Tolerance, Lipoprotein Profile and Atherosclerotic Plaque Development in ApoE-Deficient Mice. PLoS One 2016; 11:e0146439. [PMID: 26799618 PMCID: PMC4723129 DOI: 10.1371/journal.pone.0146439] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/17/2015] [Indexed: 12/15/2022] Open
Abstract
The importance of the gut microbiota (GM) in disease development has recently received increased attention, and numerous approaches have been made to better understand this important interplay. For example, metabolites derived from the GM have been shown to promote atherosclerosis, the underlying cause of cardiovascular disease (CVD), and to increase CVD risk factors. Popular interest in the role of the intestine in a variety of disease states has now resulted in a significant proportion of individuals without coeliac disease switching to gluten-free diets. The effect of gluten-free diets on atherosclerosis and cardiovascular risk factors is largely unknown. We therefore investigated the effect of a gluten-free high-fat cholesterol-rich diet, as compared to the same diet in which the gluten peptide gliadin had been added back, on atherosclerosis and several cardiovascular risk factors in apolipoprotein E-deficient (Apoe-/-) mice. The gluten-free diet transiently altered GM composition in these mice, as compared to the gliadin-supplemented diet, but did not alter body weights, glucose tolerance, insulin levels, plasma lipids, or atherosclerosis. In parallel, other Apoe-/- mice fed the same diets were treated with ampicillin, a broad-spectrum antibiotic known to affect GM composition. Ampicillin-treatment had a marked and sustained effect on GM composition, as expected. Furthermore, although ampicillin-treated mice were slightly heavier than controls, ampicillin-treatment transiently improved glucose tolerance both in the absence or presence of gliadin, reduced plasma LDL and VLDL cholesterol levels, and reduced aortic atherosclerotic lesion area. These results demonstrate that a gluten-free diet does not seem to have beneficial effects on atherosclerosis or several CVD risk factors in this mouse model, but that sustained alteration of GM composition with a broad-spectrum antibiotic has beneficial effects on CVD risk factors and atherosclerosis. These findings support the concept that altering the microbiota might provide novel treatment strategies for CVD.
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28
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Fu L, Bruckbauer A, Li F, Cao Q, Cui X, Wu R, Shi H, Zemel MB, Xue B. Interaction between metformin and leucine in reducing hyperlipidemia and hepatic lipid accumulation in diet-induced obese mice. Metabolism 2015; 64:1426-34. [PMID: 26303871 DOI: 10.1016/j.metabol.2015.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 06/18/2015] [Accepted: 07/13/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND Leucine stimulates Sirt1 and AMPK signaling in vitro and in vivo. Since metformin converges on the same pathway, we have tested the ability of leucine to amplify the effects of metformin on AMPK-mediated hepatic lipid metabolism in diet-induced-obese insulin-resistant mice. METHODS Mice were fed high leucine (24 g/kg diet) with or without sub-therapeutic levels of metformin (0.05-0.50 g/kg diet) or therapeutic levels of metformin (1.5 g/kg diet; ~300 mg/kg body weight). RESULTS High-fat diet produced a 10-fold increase in inguinal fat pad weight and 25% increase in liver weight, histologically confirmed as steatosis. The leucine-metformin combinations reduced fat pad mass, normalized liver weight, liver and plasma lipids and inflammatory markers (interleukin 6, interleukin 1 beta, tumor necrosis factor alpha, monocyte chemotactic protein-1, C-reactive protein) comparable to the effects of therapeutic metformin. Moreover, the highest sub-therapeutic levels of metformin with leucine exerted significantly greater effects than therapeutic levels of metformin and fully reversed hepatic steatosis. These effects were mediated by upregulation of hepatic AMPK and associated changes in lipogenic gene expression (fatty acid synthase, stearoyl CoA desaturase, acetyl CoA carboxylase) in the liver. CONCLUSION A low-dose leucine-metformin combination exerts comparable effects on adiposity to therapeutic doses of metformin and fully reverses hepatic steatosis in diet-induced-obese mice.
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Affiliation(s)
- Lizhi Fu
- Center for Obesity Reversal, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA
| | - Antje Bruckbauer
- NuSirt Biopharma Inc., 3835 Cleghorn Ave, Nashville, TN 37215, USA
| | - Fenfen Li
- Center for Obesity Reversal, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA
| | - Qiang Cao
- Center for Obesity Reversal, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA
| | - Xin Cui
- Center for Obesity Reversal, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA
| | - Rui Wu
- Center for Obesity Reversal, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA
| | - Hang Shi
- Center for Obesity Reversal, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA
| | - Michael B Zemel
- NuSirt Biopharma Inc., 3835 Cleghorn Ave, Nashville, TN 37215, USA
| | - Bingzhong Xue
- Center for Obesity Reversal, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA.
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29
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Cao Q, Wang X, Jia L, Mondal AK, Diallo A, Hawkins GA, Das SK, Parks JS, Yu L, Shi H, Shi H, Xue B. Inhibiting DNA Methylation by 5-Aza-2'-deoxycytidine ameliorates atherosclerosis through suppressing macrophage inflammation. Endocrinology 2014; 155:4925-38. [PMID: 25251587 PMCID: PMC4239421 DOI: 10.1210/en.2014-1595] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Inflammation marks all stages of atherogenesis. DNA hypermethylation in the whole genome or specific genes is associated with inflammation and cardiovascular diseases. Therefore, we aimed to study whether inhibiting DNA methylation by DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) ameliorates atherosclerosis in low-density lipoprotein receptor knockout (Ldlr(-/-)) mice. Ldlr(-/-) mice were fed an atherogenic diet and adminisered saline or 5-aza-dC (0.25 mg/kg) for up to 30 weeks. 5-aza-dC treatment markedly decreased atherosclerosis development in Ldlr(-/-) mice without changes in body weight, plasma lipid profile, macrophage cholesterol levels and plaque lipid content. Instead, this effect was associated with decreased macrophage inflammation. Macrophages with 5-aza-dC treatment had downregulated expression of genes involved in inflammation (TNF-α, IL-6, IL-1β, and inducible nitric oxidase) and chemotaxis (CD62/L-selectin, chemokine [C-C motif] ligand 2/MCP-1 [CCL2/MCP-1], CCL5, CCL9, and CCL2 receptor CCR2). This resulted in attenuated macrophage migration and adhesion to endothelial cells and reduced macrophage infiltration into atherosclerotic plaques. 5-aza-dC also suppressed macrophage endoplasmic reticulum stress, a key upstream signal that activates macrophage inflammation and apoptotic pathways. Finally, 5-aza-dC demethylated liver X receptor α (LXRα) and peroxisome proliferator-activated receptor γ1 (PPARγ1) promoters, which are both enriched with CpG sites. This led to overexpression of LXRα and PPARγ, which may be responsible for 5-aza-dC's anti-inflammatory and atheroprotective effect. Our findings provide strong evidence that DNA methylation may play a significant role in cardiovascular diseases and serve as a therapeutic target for prevention and treatment of atherosclerosis.
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Affiliation(s)
- Qiang Cao
- Department of Biology and Center for Obesity Reversal (Q.C., H.S., B.X.), Georgia State University, Atlanta, Georgia; Departments of Internal Medicine (Q.C., X.W., A.K.M., A.D., G.A.H., S.K.D., H.S., B.X.) and Pathology (J.S.P.), Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Internal Medicine (L.J.), University of Texas, Southwestern Medical Center, Dallas, Texas; Department of Animal and Avian Sciences (L.Y.), University of Maryland, College Park, Maryland; and Department of Biochemistry and Molecular Biology (H.S.), Georgia Regents University, Augusta, Georgia
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Zhang J, Sawyer JK, Marshall SM, Kelley KL, Davis MA, Wilson MD, Brown JM, Rudel LL. Cholesterol esters (CE) derived from hepatic sterol O-acyltransferase 2 (SOAT2) are associated with more atherosclerosis than CE from intestinal SOAT2. Circ Res 2014; 115:826-33. [PMID: 25239141 PMCID: PMC4209196 DOI: 10.1161/circresaha.115.304378] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Cholesterol esters (CE), especially cholesterol oleate, generated by hepatic and intestinal sterol O-acyltransferase 2 (SOAT2) play a critical role in cholesterol homeostasis. However, it is unknown whether the contribution of intestine-derived CE from SOAT2 would have similar effects in promoting atherosclerosis progression as for liver-derived CE. OBJECTIVE To test whether, in low-density lipoprotein receptor null (LDLr(-/-)) mice, the conditional knockout of intestinal SOAT2 (SOAT2(SI-/SI-)) or hepatic SOAT2 (SOAT2(L-/L-)) would equally limit atherosclerosis development compared with the global deletion of SOAT2 (SOAT2(-/-)). METHODS AND RESULTS SOAT2 conditional knockout mice were bred with LDLr(-/-) mice creating LDLr(-/-) mice with each of the specific SOAT2 gene deletions. All mice then were fed an atherogenic diet for 16 weeks. SOAT2(SI-/SI-)LDLr(-/-) and SOAT2(-/-)LDLr(-/-) mice had significantly lower levels of intestinal cholesterol absorption, more fecal sterol excretion, and lower biliary cholesterol levels. Analysis of plasma LDL showed that all mice with SOAT2 gene deletions had LDL CE with reduced percentages of cholesterol palmitate and cholesterol oleate. Each of the LDLr(-/-) mice with SOAT2 gene deletions had lower accumulations of total cholesterol and CE in the liver compared with control mice. Finally, aortic atherosclerosis development was significantly lower in all mice with global or tissue-restricted SOAT2 gene deletions. Nevertheless, SOAT2(-/-)LDLr(-/-) and SOAT2(L-/L-)LDLr(-/-) mice had less aortic CE accumulation and smaller aortic lesions than SOAT2(SI-/SI-)LDLr(-/-) mice. CONCLUSIONS SOAT2-derived CE from both the intestine and liver significantly contribute to the development of atherosclerosis, although the CE from the hepatic enzyme appeared to promote more atherosclerosis development.
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Affiliation(s)
- Jun Zhang
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.)
| | - Janet K Sawyer
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.)
| | - Stephanie M Marshall
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.)
| | - Kathryn L Kelley
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.)
| | - Matthew A Davis
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.)
| | - Martha D Wilson
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.)
| | - J Mark Brown
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.)
| | - Lawrence L Rudel
- From the Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (J.Z., J.K.S., S.M.M., K.L.K., M.A.D., M.D.W., L.L.R.); and Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, OH (S.M.M., J.M.B.).
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Pramfalk C, Eriksson M, Parini P. Role of TG-interacting factor (Tgif) in lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:9-12. [PMID: 25088698 DOI: 10.1016/j.bbalip.2014.07.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/17/2014] [Accepted: 07/24/2014] [Indexed: 11/18/2022]
Abstract
TG interacting factors (Tgifs) 1 and 2 are members of the TALE (three-amino-acid loop extension) superfamily of homeodomain proteins. These two proteins bind to the same DNA sequence and share a conserved C-terminal repression domain. Mutations in TGIF1 have been linked to holoprosencephaly, which is a human genetic disease that affects craniofacial development. As these proteins can interact with the ligand binding domain of retinoid X receptor α, a common heterodimeric partner of several nuclear receptors [e.g., liver X receptors (LXRs) and peroxisome proliferator-activated receptors (PPARs)], Tgif1 and Tgif2 might repress other transcriptional pathways activated by lipids. In line with this, Tgif1 interacts with LXRα and Tgif1 null mice have increased expression of the two Lxrα target genes apolipoproteins (Apo) c2 and a4. Also, we have recently identified Tgif1 to function as a transcriptional repressor of the cholesterol esterifying enzyme acyl-coenzyme A:cholesterol acyltransferase 2 (gene name SOAT2). As no studies yet have shown involvement of Tgif2 in the lipid metabolism, this review will focus on the role of Tgif1 in lipid and cholesterol metabolism. This article is part of a Special Issue entitled: Linking transcription to physiology in lipodomics.
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Affiliation(s)
- Camilla Pramfalk
- Division of Clinical Chemistry, Department of Laboratory Medicine, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Sweden; Molecular Nutrition Unit, Department of Biosciences and Nutrition, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Sweden
| | - Mats Eriksson
- Molecular Nutrition Unit, Department of Biosciences and Nutrition, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Sweden; Metabolism Unit, Department of Endocrinology, Metabolism and Diabetes, and Department of Medicine, Karolinska Institutet at Karolinska University Hospital, Huddinge, S-141 86 Stockholm, Sweden
| | - Paolo Parini
- Division of Clinical Chemistry, Department of Laboratory Medicine, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Sweden; Molecular Nutrition Unit, Department of Biosciences and Nutrition, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Sweden.
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Iqbal J, Boutjdir M, Rudel LL, Hussain MM. Intestine-specific MTP and global ACAT2 deficiency lowers acute cholesterol absorption with chylomicrons and HDLs. J Lipid Res 2014; 55:2261-75. [PMID: 25030663 DOI: 10.1194/jlr.m047951] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intestinal cholesterol absorption involves the chylomicron and HDL pathways and is dependent on microsomal triglyceride transfer protein (MTP) and ABCA1, respectively. Chylomicrons transport free and esterified cholesterol, whereas HDLs transport free cholesterol. ACAT2 esterifies cholesterol for secretion with chylomicrons. We hypothesized that free cholesterol accumulated during ACAT2 deficiency may be secreted with HDLs when chylomicron assembly is blocked. To test this, we studied cholesterol absorption in mice deficient in intestinal MTP, global ACAT2, and both intestinal MTP and global ACAT2. Intestinal MTP ablation significantly increased intestinal triglyceride and cholesterol levels and reduced their transport with chylomicrons. In contrast, global ACAT2 deficiency had no effect on triglyceride absorption but significantly reduced cholesterol absorption with chylomicrons and increased cellular free cholesterol. Their combined deficiency reduced cholesterol secretion with both chylomicrons and HDLs. Thus, contrary to our hypothesis, free cholesterol accumulated in the absence of MTP and ACAT2 is unavailable for secretion with HDLs. Global ACAT2 deficiency causes mild hypertriglyceridemia and reduces hepatosteatosis in mice fed high cholesterol diets by increasing hepatic lipoprotein production by unknown mechanisms. We show that this phenotype is preserved in the absence of intestinal MTP in global ACAT2-deficient mice fed a Western diet. Further, we observed increases in hepatic MTP activity in these mice. Thus, ACAT2 deficiency might increase MTP expression to avoid hepatosteatosis in cholesterol-fed animals. Therefore, ACAT2 inhibition might avert hepatosteatosis associated with high cholesterol diets by increasing hepatic MTP expression and lipoprotein production.
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Affiliation(s)
- Jahangir Iqbal
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203 Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY 11209
| | - Mohamed Boutjdir
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203 Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY 11209
| | - Lawrence L Rudel
- Departments of Pathology and Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC 27104
| | - M Mahmood Hussain
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203 Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY 11209
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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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Abstract
PURPOSE OF REVIEW To summarize the evidence for the presence of two lipid absorption pathways and their regulation. RECENT FINDINGS Lipid absorption involves hydrolysis of dietary fat in the lumen of the intestine, followed by the uptake of hydrolyzed products by enterocytes. Lipids are resynthesized in the endoplasmic reticulum and are either secreted with chylomicrons and HDLs or stored as cytoplasmic lipid droplets. Lipids in the droplets are hydrolyzed and are secreted at a later time. Secretion of lipids by the chylomicron and HDL pathways are dependent on microsomal triglyceride transfer protein (MTP) and ATP-binding cassette family A protein 1, respectively, and are regulated independently. Gene-ablation studies showed that MTP function and chylomicron assembly is essential for the absorption of triglycerides. Ablation of MTP abolishes triglyceride absorption and results in massive triglyceride accumulation in enterocytes. Although the majority of phospholipid, cholesterol, and vitamin E are absorbed through the chylomicron pathway, a significant amount of these lipids are also absorbed via the HDL pathway. Chylomicron assembly and secretion is increased by the enhanced availability of fatty acids, whereas the HDL pathway is upregulated by liver X receptor agonists. SUMMARY Triglycerides are exclusively transported with chylomicrons and this process is critically dependent on MTP. In addition to chylomicrons, absorption of phospholipids, free cholesterol, retinol, and vitamin E also involves HDLs. These two pathways are complementary and are regulated independently. They may be targeted to lower lipid absorption in order to control hyperlipidemia, obesity, metabolic syndrome, steatosis, insulin resistance, atherosclerosis, and other disorders.
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Affiliation(s)
- M Mahmood Hussain
- aDepartment of Cell Biology bDepartment of Pediatrics, SUNY Downstate Medical Center cVA New York Harbor Healthcare System, Brooklyn, New York, USA
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35
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Pedrelli M, Davoodpour P, Degirolamo C, Gomaraschi M, Graham M, Ossoli A, Larsson L, Calabresi L, Gustafsson JÅ, Steffensen KR, Eriksson M, Parini P. Hepatic ACAT2 knock down increases ABCA1 and modifies HDL metabolism in mice. PLoS One 2014; 9:e93552. [PMID: 24695360 PMCID: PMC3973598 DOI: 10.1371/journal.pone.0093552] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 03/06/2014] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES ACAT2 is the exclusive cholesterol-esterifying enzyme in hepatocytes and enterocytes. Hepatic ABCA1 transfers unesterified cholesterol (UC) to apoAI, thus generating HDL. By changing the hepatic UC pool available for ABCA1, ACAT2 may affect HDL metabolism. The aim of this study was to reveal whether hepatic ACAT2 influences HDL metabolism. DESIGN WT and LXRα/β double knockout (DOKO) mice were fed a western-type diet for 8 weeks. Animals were i.p. injected with an antisense oligonucleotide targeted to hepatic ACAT2 (ASO6), or with an ASO control. Injections started 4 weeks after, or concomitantly with, the beginning of the diet. RESULTS ASO6 reduced liver cholesteryl esters, while not inducing UC accumulation. ASO6 increased hepatic ABCA1 protein independently of the diet conditions. ASO6 affected HDL lipids (increased UC) only in DOKO, while it increased apoE-containing HDL in both genotypes. In WT mice ASO6 led to the appearance of large HDL enriched in apoAI and apoE. CONCLUSIONS The use of ASO6 revealed a new pathway by which the liver may contribute to HDL metabolism in mice. ACAT2 seems to be a hepatic player affecting the cholesterol fluxes fated to VLDL or to HDL, the latter via up-regulation of ABCA1.
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Affiliation(s)
- Matteo Pedrelli
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Molecular Nutrition Unit, Department of Bioscience and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Padideh Davoodpour
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Chiara Degirolamo
- Division of Lipid Science, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Monica Gomaraschi
- Department of Pharmacological Sciences, University of Milan, Milan, Italy
| | - Mark Graham
- Cardiovascular Group, Department of Antisense Drug Discovery, Isis Pharmaceuticals, Inc., Carlsbad, California, United States of America
| | - Alice Ossoli
- Department of Pharmacological Sciences, University of Milan, Milan, Italy
| | - Lilian Larsson
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Laura Calabresi
- Department of Pharmacological Sciences, University of Milan, Milan, Italy
| | - Jan-Åke Gustafsson
- Molecular Nutrition Unit, Department of Bioscience and Nutrition, Karolinska Institutet, Stockholm, Sweden
- Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, Texas, United States of America
| | - Knut R. Steffensen
- Molecular Nutrition Unit, Department of Bioscience and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Mats Eriksson
- Molecular Nutrition Unit, Department of Bioscience and Nutrition, Karolinska Institutet, Stockholm, Sweden
- Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Paolo Parini
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Molecular Nutrition Unit, Department of Bioscience and Nutrition, Karolinska Institutet, Stockholm, Sweden
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Pramfalk C, Melhuish TA, Wotton D, Jiang ZY, Eriksson M, Parini P. TG-interacting factor 1 acts as a transcriptional repressor of sterol O-acyltransferase 2. J Lipid Res 2014; 55:709-17. [PMID: 24478032 PMCID: PMC3966704 DOI: 10.1194/jlr.m045922] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/26/2014] [Indexed: 11/20/2022] Open
Abstract
Acat2 [gene name: sterol O-acyltransferase 2 (SOAT2)] esterifies cholesterol in enterocytes and hepatocytes. This study aims to identify repressor elements in the human SOAT2 promoter and evaluate their in vivo relevance. We identified TG-interacting factor 1 (Tgif1) to function as an important repressor of SOAT2. Tgif1 could also block the induction of the SOAT2 promoter activity by hepatocyte nuclear factor 1α and 4α. Women have ∼ 30% higher hepatic TGIF1 mRNA compared with men. Depletion of Tgif1 in mice increased the hepatic Soat2 expression and resulted in higher hepatic lipid accumulation and plasma cholesterol levels. Tgif1 is a new player in human cholesterol metabolism.
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Affiliation(s)
- Camilla Pramfalk
- Division of Clinical Chemistry, Department of Laboratory Medicine, and Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
- Molecular Nutrition Unit, Department of Biosciences and Nutrition, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Tiffany A. Melhuish
- Department of Biochemistry and Molecular Genetics and Center for Cell Signaling, University of Virginia, Charlottesville, VA
| | - David Wotton
- Department of Biochemistry and Molecular Genetics and Center for Cell Signaling, University of Virginia, Charlottesville, VA
| | - Zhao-Yan Jiang
- Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; and
| | - Mats Eriksson
- Molecular Nutrition Unit, Department of Biosciences and Nutrition, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
- Metabolism Unit, Department of Endocrinology, Metabolism and Diabetes, and Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Paolo Parini
- Division of Clinical Chemistry, Department of Laboratory Medicine, and Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
- Molecular Nutrition Unit, Department of Biosciences and Nutrition, Centre for Nutrition and Toxicology, NOVUM, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
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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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Hansel MC, Gramignoli R, Blake W, Davila J, Skvorak K, Dorko K, Tahan V, Lee BR, Tafaleng E, Guzman-Lepe J, Soto-Gutierrez A, Fox IJ, Strom SC. Increased reprogramming of human fetal hepatocytes compared with adult hepatocytes in feeder-free conditions. Cell Transplant 2014; 23:27-38. [PMID: 23394081 PMCID: PMC3773298 DOI: 10.3727/096368912x662453] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Hepatocyte transplantation has been used to treat liver disease. The availability of cells for these procedures is quite limited. Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) may be a useful source of hepatocytes for basic research and transplantation if efficient and effective differentiation protocols were developed and problems with tumorigenicity could be overcome. Recent evidence suggests that the cell of origin may affect hiPSC differentiation. Thus, hiPSCs generated from hepatocytes may differentiate back to hepatocytes more efficiently than hiPSCs from other cell types. We examined the efficiency of reprogramming adult and fetal human hepatocytes. The present studies report the generation of 40 hiPSC lines from primary human hepatocytes under feeder-free conditions. Of these, 37 hiPSC lines were generated from fetal hepatocytes, 2 hiPSC lines from normal hepatocytes, and 1 hiPSC line from hepatocytes of a patient with Crigler-Najjar syndrome, type 1. All lines were confirmed reprogrammed and expressed markers of pluripotency by gene expression, flow cytometry, immunocytochemistry, and teratoma formation. Fetal hepatocytes were reprogrammed at a frequency over 50-fold higher than adult hepatocytes. Adult hepatocytes were only reprogrammed with six factors, while fetal hepatocytes could be reprogrammed with three (OCT4, SOX2, NANOG) or four factors (OCT4, SOX2, NANOG, LIN28 or OCT4, SOX2, KLF4, C-MYC). The increased reprogramming efficiency of fetal cells was not due to increased transduction efficiency or vector toxicity. These studies confirm that hiPSCs can be generated from adult and fetal hepatocytes including those with genetic diseases. Fetal hepatocytes reprogram much more efficiently than adult hepatocytes, although both could serve as useful sources of hiPSC-derived hepatocytes for basic research or transplantation.
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Affiliation(s)
- Marc C. Hansel
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, USA
| | - Roberto Gramignoli
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - William Blake
- Genetically Modified Models Center of Emphasis, Pfizer, Groton, Connecticut, USA
| | - Julio Davila
- Genetically Modified Models Center of Emphasis, Pfizer, Groton, Connecticut, USA
| | - Kristen Skvorak
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Kenneth Dorko
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Veysel Tahan
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Brian R. Lee
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Edgar Tafaleng
- Genetically Modified Models Center of Emphasis, Pfizer, Groton, Connecticut, USA
| | - Jorge Guzman-Lepe
- Center for Innovative Regenerative Therapies, Department of Surgery, Transplantation Section, Children’s Hospital of Pittsburgh
| | - Alejandro Soto-Gutierrez
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Center for Innovative Regenerative Therapies, Department of Surgery, Transplantation Section, Children’s Hospital of Pittsburgh
| | - Ira J. Fox
- McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, USA
- Center for Innovative Regenerative Therapies, Department of Surgery, Transplantation Section, Children’s Hospital of Pittsburgh
| | - Stephen C. Strom
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, USA
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Iqbal J, Parks JS, Hussain MM. Lipid absorption defects in intestine-specific microsomal triglyceride transfer protein and ATP-binding cassette transporter A1-deficient mice. J Biol Chem 2013; 288:30432-30444. [PMID: 24019513 DOI: 10.1074/jbc.m113.501247] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We have previously described apolipoprotein B (apoB)-dependent and -independent cholesterol absorption pathways and the role of microsomal triglyceride transfer protein (MTP) and ATP-binding cassette transporter A1 (ABCA1) in these pathways. To assess the contribution of these pathways to cholesterol absorption and to determine whether there are other pathways, we generated mice that lack MTP and ABCA1, individually and in combination, in the intestine. Intestinal deletions of Mttp and Abca1 decreased plasma cholesterol concentrations by 45 and 24%, respectively, whereas their combined deletion reduced it by 59%. Acute cholesterol absorption was reduced by 28% in the absence of ABCA1, and it was reduced by 92-95% when MTP was deleted in the intestine alone or together with ABCA1. MTP deficiency significantly reduced triglyceride absorption, although ABCA1 deficiency had no effect. ABCA1 deficiency did not affect cellular lipids, but Mttp deficiency significantly increased intestinal levels of triglycerides and free fatty acids. Accumulation of intestinal free fatty acids, but not triglycerides, in Mttp-deficient intestines was prevented when mice were also deficient in intestinal ABCA1. Combined deficiency of these genes increased intestinal fatty acid oxidation as a consequence of increased expression of peroxisome proliferator-activated receptor-γ (PPARγ) and carnitine palmitoyltransferase 1α (CPT1α). These studies show that intestinal MTP and ABCA1 are critical for lipid absorption and are the main determinants of plasma and intestinal lipid levels. Reducing their activities might lower plasma lipid concentrations.
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Affiliation(s)
- Jahangir Iqbal
- From the Departments of Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, New York 11203 and
| | - John S Parks
- the Department of Pathology, Section on Lipid Sciences and Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 25157
| | - M Mahmood Hussain
- From the Departments of Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, New York 11203 and.
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Bi X, Zhu X, Duong M, Boudyguina EY, Wilson MD, Gebre AK, Parks JS. Liver ABCA1 deletion in LDLrKO mice does not impair macrophage reverse cholesterol transport or exacerbate atherogenesis. Arterioscler Thromb Vasc Biol 2013; 33:2288-96. [PMID: 23814116 DOI: 10.1161/atvbaha.112.301110] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Hepatic ATP binding cassette transporter A1 (ABCA1) expression is critical for maintaining plasma high-density lipoprotein (HDL) concentrations, but its role in macrophage reverse cholesterol transport and atherosclerosis is not fully understood. We investigated atherosclerosis development and reverse cholesterol transport in hepatocyte-specific ABCA1 knockout (HSKO) mice in the low-density lipoprotein (LDL) receptor KO (LDLrKO) C57BL/6 background. APPROACH AND RESULTS Male and female LDLrKO and HSKO/LDLrKO mice were switched from chow at 8 weeks of age to an atherogenic diet (10% palm oil, 0.2% cholesterol) for 16 weeks. Chow-fed HSKO/LDLrKO mice had HDL concentrations 10% to 20% of LDLrKO mice, but similar very low-density lipoprotein and LDL concentrations. Surprisingly, HSKO/LDLrKO mice fed the atherogenic diet had significantly lower (40% to 60%) very low-density lipoprotein, LDL, and HDL concentrations (50%) compared with LDLrKO mice. Aortic surface lesion area and cholesterol content were similar for both genotypes of mice, but aortic root intimal area was significantly lower (20% to 40%) in HSKO/LDLrKO mice. Although macrophage (3)H-cholesterol efflux to apoB lipoprotein-depleted plasma was 24% lower for atherogenic diet-fed HSKO/LDLrKO versus LDLrKO mice, variation in percentage efflux among individual mice was <2-fold compared with a 10-fold variation in plasma HDL concentrations, suggesting that HDL levels, per se, were not the primary determinant of plasma efflux capacity. In vivo reverse cholesterol transport, resident peritoneal macrophage sterol content, biliary lipid composition, and fecal cholesterol mass were similar between both genotypes of mice. CONCLUSIONS The markedly reduced plasma HDL pool in HSKO/LDLrKO mice is sufficient to maintain macrophage reverse cholesterol transport, which, along with reduced plasma very low-density lipoprotein and LDL concentrations, prevented the expected increase in atherosclerosis.
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Affiliation(s)
- Xin Bi
- From the Section on Lipid Sciences, Department of Pathology (X.B., X.Z., M.D., E.Y.B., M.D.W., A.K.G., J.S.P.), and Department of Biochemistry (J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
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41
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Melchior JT, Sawyer JK, Kelley KL, Shah R, Wilson MD, Hantgan RR, Rudel LL. LDL particle core enrichment in cholesteryl oleate increases proteoglycan binding and promotes atherosclerosis. J Lipid Res 2013; 54:2495-503. [PMID: 23804810 DOI: 10.1194/jlr.m039644] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several studies in humans and animals suggest that LDL particle core enrichment in cholesteryl oleate (CO) is associated with increased atherosclerosis. Diet enrichment with MUFAs enhances LDL CO content. Steroyl O-acyltransferase 2 (SOAT2) is the enzyme that catalyzes the synthesis of much of the CO found in LDL, and gene deletion of SOAT2 minimizes CO in LDL and protects against atherosclerosis. The purpose of this study was to test the hypothesis that the increased atherosclerosis associated with LDL core enrichment in CO results from an increased affinity of the LDL particle for arterial proteoglycans. ApoB-100-only Ldlr(-/-) mice with and without Soat2 gene deletions were fed diets enriched in either cis-MUFA or n-3 PUFA, and LDL particles were isolated. LDL:proteogylcan binding was measured using surface plasmon resonance. Particles with higher CO content consistently bound with higher affinity to human biglycan and the amount of binding was shown to be proportional to the extent of atherosclerosis of the LDL donor mice. The data strongly support the thesis that atherosclerosis was induced through enhanced proteoglycan binding of LDL resulting from LDL core CO enrichment.
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Affiliation(s)
- John T Melchior
- Department of Pathology, Section of Lipid Sciences, Wake Forest University School of Medicine, Winston Salem, NC, USA
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42
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Yang L, Han G, Liu QH, Wu Q, He HJ, Cheng CZ, Duan YJ. Rice protein exerts a hypocholesterolemic effect through regulating cholesterol metabolism-related gene expression and enzyme activity in adult rats fed a cholesterol-enriched diet. Int J Food Sci Nutr 2013; 64:836-42. [PMID: 23763670 DOI: 10.3109/09637486.2013.804038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The major aim of this study is to elucidate the hypocholesterolemic mechanism exerted by rice protein (RP) in adult rats under cholesterol-enriched dietary condition. Compared with casein, the cholesterol levels in plasma and the liver were significantly reduced by RP, accompanying significant inhibition of cholesterol absorption. RP increased the activity and mRNA level of cholesterol 7α-hydroxylase, whereas acyl-CoA:cholesterol acyltransferase activity and gene expression were significantly depressed with consumption of RP. Neither the activity nor gene expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase of RP differed from that of casein. The gene expression of the peroxisome proliferator-activated receptor α and liver X receptor α were significantly activated by consumption of RP. RP did not modify the mRNA level of sterol regulatory element-binding protein-2 with respect to casein. These results suggest RP can induce a cholesterol-lowering effect through modifying cholesterol metabolism-related gene expression and enzyme activity in adult rats.
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Affiliation(s)
- Lin Yang
- Department of Food Science, School of Food Science and Engineering, Harbin Institute of Technology , Harbin , China
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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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44
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Rong JX, Blachford C, Feig JE, Bander I, Mayne J, Kusunoki J, Miller C, Davis M, Wilson M, Dehn S, Thorp E, Tabas I, Taubman MB, Rudel LL, Fisher EA. ACAT inhibition reduces the progression of preexisting, advanced atherosclerotic mouse lesions without plaque or systemic toxicity. Arterioscler Thromb Vasc Biol 2012; 33:4-12. [PMID: 23139293 DOI: 10.1161/atvbaha.112.252056] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Acyl-CoA:cholesterol acyltransferase (ACAT) converts cholesterol to cholesteryl esters in plaque foam cells. Complete deficiency of macrophage ACAT has been shown to increase atherosclerosis in hypercholesterolemic mice because of cytotoxicity from free cholesterol accumulation, whereas we previously showed that partial ACAT inhibition by Fujirebio compound F1394 decreased early atherosclerosis development. In this report, we tested F1394 effects on preestablished, advanced lesions of apolipoprotein-E-deficient mice. METHODS AND RESULTS Apolipoprotein-E-deficient mice on Western diet for 14 weeks developed advanced plaques, and were either euthanized (Baseline), or continued on Western diet with or without F1394 and euthanized after 14 more weeks. F1394 was not associated with systemic toxicity. Compared with the baseline group, lesion size progressed in both groups; however, F1394 significantly retarded plaque progression and reduced plaque macrophage, free and esterified cholesterol, and tissue factor contents compared with the untreated group. Apoptosis of plaque cells was not increased, consistent with the decrease in lesional free cholesterol. There was no increase in plaque necrosis and unimpaired efferocytosis (phagocytic clearance of apoptotic cells). The effects of F1394 were independent of changes in plasma cholesterol levels. CONCLUSIONS Partial ACAT inhibition by F1394 lowered plaque cholesterol content and had other antiatherogenic effects in advanced lesions in apolipoprotein-E-deficient mice without overt systemic or plaque toxicity, suggesting the continued potential of ACAT inhibition for the clinical treatment of atherosclerosis, in spite of recent trial data.
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Affiliation(s)
- James X Rong
- Marc and Ruti Bell Vascular Biology and Disease Research Program of the Leon H. Charney Division of Cardiology and the Department of Medicine (Cardiology), New York University School of Medicine, Smilow 7, 522 First Ave, New York, NY 10029, USA
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45
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Xie 谢畅 C, Zhou 周章森 ZS, Li 李钠 N, Bian 卞艳 Y, Wang 王永建 YJ, Wang 王丽娟 LJ, Li 李伯良 BL, Song 宋保亮 BL. Ezetimibe blocks the internalization of NPC1L1 and cholesterol in mouse small intestine. J Lipid Res 2012; 53:2092-2101. [PMID: 22811412 PMCID: PMC3435542 DOI: 10.1194/jlr.m027359] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 07/05/2012] [Indexed: 11/20/2022] Open
Abstract
The multiple transmembrane protein Niemann-Pick C1 like1 (NPC1L1) is essential for intestinal cholesterol absorption. Ezetimibe binds to NPC1L1 and is a clinically used cholesterol absorption inhibitor. Recent studies in cultured cells have shown that NPC1L1 mediates cholesterol uptake through vesicular endocytosis that can be blocked by ezetimibe. However, how NPC1L1 and ezetimibe work in the small intestine is unknown. In this study, we found that NPC1L1 distributed in enterocytes of villi and transit-amplifying cells of crypts. Acyl-CoA cholesterol acyltransferase 2 (ACAT2), another important protein for cholesterol absorption by providing cholesteryl esters to chylomicrons, was mainly presented in the apical cytoplasm of enterocytes. NPC1L1 and ACAT2 were highly expressed in jejunum and ileum. ACAT1 presented in the Paneth cells of crypts and mesenchymal cells of villi. In the absence of cholesterol, NPC1L1 was localized on the brush border of enterocytes. Dietary cholesterol induced the internalization of NPC1L1 to the subapical layer beneath the brush border and became partially colocalized with the endosome marker Rab11. Ezetimibe blocked the internalization of NPC1L1 and cholesterol and caused their retention in the plasma membrane. This study demonstrates that NPC1L1 mediates cholesterol entering enterocytes through vesicular endocytosis and that ezetimibe blocks this step in vivo.
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Affiliation(s)
- Chang Xie 谢畅
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhang-Sen Zhou 周章森
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Na Li 李钠
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yan Bian 卞艳
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yong-Jian Wang 王永建
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Li-Juan Wang 王丽娟
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bo-Liang Li 李伯良
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Bao-Liang Song 宋保亮
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
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46
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Nguyen TM, Sawyer JK, Kelley KL, Davis MA, Kent CR, Rudel LL. ACAT2 and ABCG5/G8 are both required for efficient cholesterol absorption in mice: evidence from thoracic lymph duct cannulation. J Lipid Res 2012; 53:1598-609. [PMID: 22669916 PMCID: PMC3540850 DOI: 10.1194/jlr.m026823] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 05/24/2012] [Indexed: 11/20/2022] Open
Abstract
The metabolic fate of newly absorbed cholesterol and phytosterol is orchestrated through adenosine triphosphate-binding cassette transporter G5 and G8 heterodimer (G5G8), and acyl CoA:cholesterol acyltransferase 2 (ACAT2). We hypothesized that intestinal G5G8 limits sterol absorption by reducing substrate availability for ACAT2 esterification and have attempted to define the roles of these two factors using gene deletion studies in mice. Male ACAT2(-/-), G5G8(-/-), ACAT2(-/-)G5G8(-/-) (DKO), and wild-type (WT) control mice were fed a diet with 20% of energy as palm oil and 0.2% (w/w) cholesterol. Sterol absorption efficiency was directly measured by monitoring the appearance of [(3)H]sitosterol and [(14)C]cholesterol tracers in lymph after thoracic lymph duct cannulation. The average percentage (± SEM) absorption of [(14)C]cholesterol after 8 h of lymph collection was 40.55 ± 0.76%, 19.41 ± 1.52%, 32.13 ± 1.60%, and 21.27 ± 1.35% for WT, ACAT2(-/-), G5G8(-/-), and DKO mice, respectively. [(3)H]sitosterol absorption was <2% in WT and ACAT2(-/-) mice, whereas it was up to 6.8% in G5G8(-/-) and DKO mice. G5G8(-/-) mice also produced chylomicrons with ∼70% less cholesterol ester mass than WT mice. In contrast to expectations, the data demonstrated that the absence of G5G8 led to decreased intestinal cholesterol esterification and reduced cholesterol transport efficiency. Intestinal G5G8 appeared to limit the absorption of phytosterols; ACAT2 more efficiently esterified cholesterol than phytosterols. The data indicate that handling of sterols by the intestine involves both G5G8 and ACAT2 but that an additional factor (possibly Niemann-Pick C1-like 1) may be key in determining absorption efficiency.
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Affiliation(s)
- Tam M. Nguyen
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Janet K. Sawyer
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Kathryn L. Kelley
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Matthew A. Davis
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Carol R. Kent
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Lawrence L. Rudel
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157
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47
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Abstract
Intestinal lipid transport plays a central role in fat homeostasis. Here we review the pathways regulating intestinal absorption and delivery of dietary and biliary lipid substrates, principally long-chain fatty acid, cholesterol, and other sterols. We discuss the regulation and functions of CD36 in fatty acid absorption, NPC1L1 in cholesterol absorption, as well as other lipid transporters including FATP4 and SRB1. We discuss the pathways of intestinal sterol efflux via ABCG5/G8 and ABCA1 as well as the role of the small intestine in high-density lipoprotein (HDL) biogenesis and reverse cholesterol transport. We review the pathways and genetic regulation of chylomicron assembly, the role of dominant restriction points such as microsomal triglyceride transfer protein and apolipoprotein B, and the role of CD36, l-FABP, and other proteins in formation of the prechylomicron complex. We will summarize current concepts of regulated lipoprotein secretion (including HDL and chylomicron pathways) and include lessons learned from families with genetic mutations in dominant pathways (i.e., abetalipoproteinemia, chylomicron retention disease, and familial hypobetalipoproteinemia). Finally, we will provide an integrative view of intestinal lipid homeostasis through recent findings on the role of lipid flux and fatty acid signaling via diverse receptor pathways in regulating absorption and production of satiety factors.
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Affiliation(s)
- Nada A Abumrad
- Center for Human Nutrition and Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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48
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Zhang J, Kelley KL, Marshall SM, Davis MA, Wilson MD, Sawyer JK, Farese RV, Brown JM, Rudel LL. Tissue-specific knockouts of ACAT2 reveal that intestinal depletion is sufficient to prevent diet-induced cholesterol accumulation in the liver and blood. J Lipid Res 2012; 53:1144-52. [PMID: 22460046 PMCID: PMC3351821 DOI: 10.1194/jlr.m024356] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/20/2012] [Indexed: 11/20/2022] Open
Abstract
Acyl-CoA:cholesterol acyltransferase 2 (ACAT2) generates cholesterol esters (CE) for packaging into newly synthesized lipoproteins and thus is a major determinant of blood cholesterol levels. ACAT2 is expressed exclusively in the small intestine and liver, but the relative contributions of ACAT2 expression in these tissues to systemic cholesterol metabolism is unknown. We investigated whether CE derived from the intestine or liver would differentially affect hepatic and plasma cholesterol homeostasis. We generated liver-specific (ACAT2(L-/L-)) and intestine-specific (ACAT2(SI-/SI-)) ACAT2 knockout mice and studied dietary cholesterol-induced hepatic lipid accumulation and hypercholesterolemia. ACAT2(SI-/SI-) mice, in contrast to ACAT2(L-/L-) mice, had blunted cholesterol absorption. However, specific deletion of ACAT2 in the intestine generated essentially a phenocopy of the conditional knockout of ACAT2 in the liver, with reduced levels of plasma very low-density lipoprotein and hepatic CE, yet hepatic-free cholesterol does not build up after high cholesterol intake. ACAT2(L-/L-) and ACAT2(SI-/SI-) mice were equally protected from diet-induced hepatic CE accumulation and hypercholesterolemia. These results suggest that inhibition of intestinal or hepatic ACAT2 improves atherogenic hyperlipidemia and limits hepatic CE accumulation in mice and that depletion of intestinal ACAT2 is sufficient for most of the beneficial effects on cholesterol metabolism. Inhibitors of ACAT2 targeting either tissue likely would be beneficial for atheroprotection.
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Affiliation(s)
- Jun Zhang
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Kathryn L. Kelley
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Stephanie M. Marshall
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Matthew A. Davis
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Martha D. Wilson
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Janet K. Sawyer
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Robert V. Farese
- Departments of Medicine, Biochemistry & Biophysics, Gladstone Institute of Cardiovascular Disease, University of California, San Francisco, CA 94158
| | - J. Mark Brown
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - Lawrence L. Rudel
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157
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50
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Rong S, Cao Q, Liu M, Seo J, Jia L, Boudyguina E, Gebre AK, Colvin PL, Smith TL, Murphy RC, Mishra N, Parks JS. Macrophage 12/15 lipoxygenase expression increases plasma and hepatic lipid levels and exacerbates atherosclerosis. J Lipid Res 2012; 53:686-95. [PMID: 22279185 DOI: 10.1194/jlr.m022723] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
12/15 lipoxygenase (12/15LO) oxidizes polyunsaturated fatty acids (PUFAs) to form bioactive lipid mediators. The role of 12/15LO in atherosclerosis development remains controversial. We evaluated atherosclerosis development and lipid metabolism in 12/15LO-LDL receptor (LDLr) double knockout (DK) vs. LDLr knockout (SK) mice fed a PUFA-enriched diet to enhance production of 12/15LO products. Compared with SK controls, DK mice fed a PUFA-enriched diet had decreased plasma and liver lipid levels, hepatic lipogenic gene expression, VLDL secretion, and aortic atherosclerosis and increased VLDL turnover. Bone marrow transplantation and Kupffer cell ablation studies suggested both circulating leukocytes and Kupffer cells contributed to the lipid phenotype in 12/15LO-deficient mice. Conditioned medium from in vitro incubation of DK vs. SK macrophages reduced triglyceride secretion in McArdle 7777 hepatoma cells. Our results suggest that, in the context of dietary PUFA enrichment, macrophage 12/15LO expression adversely affects plasma and hepatic lipid metabolism, resulting in exacerbated atherosclerosis.
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Affiliation(s)
- Shunxing Rong
- Department of Pathology/Section on Lipid Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
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