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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Rezaei F, Farhat D, Gursu G, Samnani S, Lee JY. Snapshots of ABCG1 and ABCG5/G8: A Sterol's Journey to Cross the Cellular Membranes. Int J Mol Sci 2022; 24:ijms24010484. [PMID: 36613930 PMCID: PMC9820320 DOI: 10.3390/ijms24010484] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/29/2022] Open
Abstract
The subfamily-G ATP-binding cassette (ABCG) transporters play important roles in regulating cholesterol homeostasis. Recent progress in the structural data of ABCG1 and ABCG5/G8 disclose putative sterol binding sites that suggest the possible cholesterol translocation pathway. ABCG1 and ABCG5/G8 share high similarity in the overall molecular architecture, and both transporters appear to use several unique structural motifs to facilitate cholesterol transport along this pathway, including the phenylalanine highway and the hydrophobic valve. Interestingly, ABCG5/G8 is known to transport cholesterol and phytosterols, whereas ABCG1 seems to exclusively transport cholesterol. Ligand docking analysis indeed suggests a difference in recruiting sterol molecules to the known sterol-binding sites. Here, we further discuss how the different and shared structural features are relevant to their physiological functions, and finally provide our perspective on future studies in ABCG cholesterol transporters.
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Affiliation(s)
- Fatemeh Rezaei
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Danny Farhat
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Gonca Gursu
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Biochemistry Program, Faculty of Science, University of Ottawa, Ottawa, ON K1H 6N5, Canada
| | - Sabrina Samnani
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Biochemistry Program, Faculty of Science, University of Ottawa, Ottawa, ON K1H 6N5, Canada
| | - Jyh-Yeuan Lee
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Correspondence:
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Tanaka Y, Kamisako T. Regulation of the expression of cholesterol transporters by lipid-lowering drugs ezetimibe and pemafibrate in rat liver and intestine. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166215. [PMID: 34265370 DOI: 10.1016/j.bbadis.2021.166215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 12/15/2022]
Abstract
Ezetimibe and pemafibrate are lipid-lowering drugs and promote reverse cholesterol transport. However, it is unknown whether cholesterol is mainly excreted by hepatobiliary excretion or by non-biliary transintestinal cholesterol efflux (TICE). We evaluated the effects of ezetimibe and pemafibrate on hepatic and intestinal cholesterol transporter regulation in Sham-operated rats, and examined the effects of these drugs on TICE in bile duct-ligated rats. Seven-week-old male Sprague-Dawley rats were treated as follows for two weeks: 1) Sham, Sham operation; 2) BDL, bile duct ligation; 3) E-Sham, Sham + ezetimibe; 4) E-BDL, BDL + ezetimibe; 5) P-Sham, Sham + pemafibrate; and 6) P-BDL, BDL + pemafibrate. Blood, liver, jejunum, and feces were collected 72 h post-surgery. Hepatic cholesterol levels were decreased in P-Sham and E-Sham, and were lower in E-BDL and P-BDL than in BDL. Fecal cholesterol levels increased in E-Sham and P-Sham compared with Sham, and were higher in E-BDL and P-BDL than in BDL. In liver, Abcg5 mRNA showed induction in E-Sham, Abcg5 and Abca1 mRNA were induced in P-Sham, Abcg5 mRNA was reduced in E-BDL, and Abca1 mRNA was increased in P-BDL. In jejunum, Abcg5 mRNA was induced in E-Sham. Abcg8 mRNA was induced in E-Sham and P-Sham. NPC1L1 mRNA showed reduced expression in P-Sham and P-BDL. SR-B1 mRNA was reduced in P-Sham, and the expression decreased in P-BDL. LDL receptor mRNA was induced in BDL and P-BDL. Ezetimibe and pemafibrate may promote TICE by increasing Abcg5/g8, while pemafibrate may inhibit intestinal cholesterol absorption by decreasing SR-B1 and NPC1L1.
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Affiliation(s)
- Yuji Tanaka
- Department of Clinical Laboratory Medicine, Kindai University Faculty of Medicine, Osakasayama, Osaka 589-8511, Japan.
| | - Toshinori Kamisako
- Department of Clinical Laboratory Medicine, Kindai University Faculty of Medicine, Osakasayama, Osaka 589-8511, Japan
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Lifsey HC, Kaur R, Thompson BH, Bennett L, Temel RE, Graf GA. Stigmasterol stimulates transintestinal cholesterol excretion independent of liver X receptor activation in the small intestine. J Nutr Biochem 2019; 76:108263. [PMID: 31759199 DOI: 10.1016/j.jnutbio.2019.108263] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 10/14/2019] [Accepted: 10/29/2019] [Indexed: 02/09/2023]
Abstract
Despite advances in healthcare, cardiovascular disease (CVD) remains the leading cause of death in the United States. Elevated levels of plasma cholesterol are highly predictive of CVD and stroke and are the principal driver of atherosclerosis. Unfortunately, current cholesterol lowering agents, such as statins, are not known to reverse atherosclerotic disease once it has been established. In preclinical models, agonists of nuclear receptor, LXR, have been shown to reduce and reverse atherosclerosis. Phytosterols are bioactive non-cholesterol sterols that act as LXR agonists and regulate cholesterol metabolism and transport. We hypothesized that stigmasterol would act as an LXR agonist and alter intestinal cholesterol secretion to promote cholesterol elimination. Mice were fed a control diet, or a diet supplemented with stigmasterol (0.3% w/w) or T0901317 (0.015% w/w), a known LXR agonist. In this experiment we analyzed the sterol content of bile, intestinal perfusate, plasma, and feces. Additionally, the liver and small intestine were analyzed for relative levels of transcripts known to be regulated by LXR. We observed that T0901317 robustly promoted cholesterol elimination and acted as a strong LXR agonist. Stigmasterol promoted transintestinal cholesterol secretion through an LXR-independent pathway.
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Affiliation(s)
| | - Rupinder Kaur
- Department of Pharmaceutical Sciences, College of Pharmacy
| | | | - Lisa Bennett
- Department of Pharmaceutical Sciences, College of Pharmacy
| | - Ryan E Temel
- Department of Physiology, College of Medicine, University of Kentucky; Saha Cardiovascular Research Center
| | - Gregory A Graf
- Department of Pharmaceutical Sciences, College of Pharmacy; Saha Cardiovascular Research Center; Barnstable Brown Diabetes and Obesity Center.
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Abstract
Besides the well-known hepatobiliary pathway of cholesterol excretion into the feces, transintestinal cholesterol excretion (TICE) is a second major pathway through which cholesterol is disposed from the body. In the process of TICE, cholesterol is taken up from lipoprotein particles at the basolateral side of the enterocyte and translocates towards the apical side of the enterocyte. At the apical side, the ATP-binding cassette transporters G5 and G8 form a heterodimer that transports cholesterol into the intestinal lumen. A substantial amount of the secreted cholesterol is likely reabsorbed by the cholesterol influx transporter Niemann-Pick C1-Like 1 (NPC1L1) since recent data indicate that inhibition of NPC1L1 increases the efficacy of TICE for disposal of cholesterol via the feces. The pathways and proteins involved in intracellular cholesterol trafficking in the enterocyte have not yet been identified. Therefore, in addition to discussing known mediators of TICE, this review will also examine potential candidates involved in cholesterol translocation in the enterocyte. Both the cholesterol reuptake and efflux pathways can be influenced by pharmaceutical means; thus, the TICE pathway is a very attractive target to increase cholesterol excretion from the body and prevent or mitigate atherosclerotic cardiovascular disease.
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Affiliation(s)
- Aldo Grefhorst
- AMSTERDAM UNIVERSITY MEDICAL CENTERS, AMSTERDAM, THE NETHERLANDS
| | - Henkjan J Verkade
- UNIVERSITY MEDICAL CENTER GRONINGEN, UNIVERSITY OF GRONINGEN, GRONINGEN, THE NETHERLANDS
| | - Albert K Groen
- AMSTERDAM UNIVERSITY MEDICAL CENTERS, AMSTERDAM, THE NETHERLANDS.,UNIVERSITY MEDICAL CENTER GRONINGEN, UNIVERSITY OF GRONINGEN, GRONINGEN, THE NETHERLANDS
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de Boer JF, Schonewille M, Boesjes M, Wolters H, Bloks VW, Bos T, van Dijk TH, Jurdzinski A, Boverhof R, Wolters JC, Kuivenhoven JA, van Deursen JM, Oude Elferink RPJ, Moschetta A, Kremoser C, Verkade HJ, Kuipers F, Groen AK. Intestinal Farnesoid X Receptor Controls Transintestinal Cholesterol Excretion in Mice. Gastroenterology 2017; 152:1126-1138.e6. [PMID: 28065787 DOI: 10.1053/j.gastro.2016.12.037] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 12/03/2016] [Accepted: 12/23/2016] [Indexed: 01/17/2023]
Abstract
BACKGROUND & AIMS The role of the intestine in the maintenance of cholesterol homeostasis increasingly is recognized. Fecal excretion of cholesterol is the last step in the atheroprotective reverse cholesterol transport pathway, to which biliary and transintestinal cholesterol excretion (TICE) contribute. The mechanisms controlling the flux of cholesterol through the TICE pathway, however, are poorly understood. We aimed to identify mechanisms that regulate and stimulate TICE. METHODS We performed studies with C57Bl/6J mice, as well as with mice with intestine-specific knockout of the farnesoid X receptor (FXR), mice that express an FXR transgene specifically in the intestine, and ABCG8-knockout mice. Mice were fed a control diet or a diet supplemented with the FXR agonist PX20606, with or without the cholesterol absorption inhibitor ezetimibe. Some mice with intestine-specific knockout of FXR were given daily injections of fibroblast growth factor (FGF)19. To determine fractional cholesterol absorption, mice were given intravenous injections of cholesterol D5 and oral cholesterol D7. Mice were given 13C-acetate in drinking water for measurement of cholesterol synthesis. Bile cannulations were performed and biliary cholesterol secretion rates were assessed. In a separate set of experiments, bile ducts of male Wistar rats were exteriorized, allowing replacement of endogenous bile by a model bile. RESULTS In mice, we found TICE to be regulated by intestinal FXR via induction of its target gene Fgf15 (FGF19 in rats and human beings). Stimulation of this pathway caused mice to excrete up to 60% of their total cholesterol content each day. PX20606 and FGF19 each increased the ratio of muricholate:cholate in bile, inducing a more hydrophilic bile salt pool. The altered bile salt pool stimulated robust secretion of cholesterol into the intestinal lumen via the sterol-exporting heterodimer adenosine triphosphate binding cassette subfamily G member 5/8 (ABCG5/G8). Of note, the increase in TICE induced by PX20606 was independent of changes in cholesterol absorption. CONCLUSIONS Hydrophilicity of the bile salt pool, controlled by FXR and FGF15/19, is an important determinant of cholesterol removal via TICE. Strategies that alter bile salt pool composition might be developed for the prevention of cardiovascular disease. Transcript profiling: http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?token=irsrayeohfcntqx&acc=GSE74101.
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Affiliation(s)
- Jan Freark de Boer
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Marleen Schonewille
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Marije Boesjes
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Henk Wolters
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Vincent W Bloks
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Trijnie Bos
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Theo H van Dijk
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Angelika Jurdzinski
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Renze Boverhof
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Justina C Wolters
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan A Kuivenhoven
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan M van Deursen
- Department of Pediatric and Adolescent Medicine, Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Ronald P J Oude Elferink
- Tytgat Institute for Liver and Intestinal Research, Department of Hepatology and Gastroenterology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Antonio Moschetta
- Department of Interdisciplinary Medicine, University of Bari, IRCCS Istituto Tumori "Giovanni Paolo II," Bari, Italy
| | | | - Henkjan J Verkade
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Folkert Kuipers
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Albert K Groen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Stöger JL, Boshuizen MCS, Brufau G, Gijbels MJJ, Wolfs IMJ, van der Velden S, Pöttgens CCH, Vergouwe MN, Wijnands E, Beckers L, Goossens P, Kerksiek A, Havinga R, Müller W, Lütjohann D, Groen AK, de Winther MPJ. Deleting myeloid IL-10 receptor signalling attenuates atherosclerosis in LDLR-/- mice by altering intestinal cholesterol fluxes. Thromb Haemost 2016; 116:565-77. [PMID: 27358035 DOI: 10.1160/th16-01-0043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 05/25/2016] [Indexed: 12/27/2022]
Abstract
Inflammatory responses and cholesterol homeostasis are interconnected in atherogenesis. Interleukin (IL)-10 is an important anti-inflammatory cytokine, known to suppress atherosclerosis development. However, the specific cell types responsible for the atheroprotective effects of IL-10 remain to be defined and knowledge on the actions of IL-10 in cholesterol homeostasis is scarce. Here we investigated the functional involvement of myeloid IL-10-mediated atheroprotection. To do so, bone marrow from IL-10 receptor 1 (IL-10R1) wild-type and myeloid IL-10R1-deficient mice was transplanted to lethally irradiated female LDLR-/- mice. Hereafter, mice were given a high cholesterol diet for 10 weeks after which atherosclerosis development and cholesterol metabolism were investigated. In vitro, myeloid IL-10R1 deficiency resulted in a pro-inflammatory macrophage phenotype. However, in vivo significantly reduced lesion size and severity was observed. This phenotype was associated with lower myeloid cell accumulation and more apoptosis in the lesions. Additionally, a profound reduction in plasma and liver cholesterol was observed upon myeloid IL-10R1 deficiency, which was reflected in plaque lipid content. This decreased hypercholesterolaemia was associated with lowered very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels, likely as a response to decreased intestinal cholesterol absorption. In addition, IL-10R1 deficient mice demonstrated substantially higher faecal sterol loss caused by increased non-biliary cholesterol efflux. The induction of this process was linked to impaired ACAT2-mediated esterification of liver and plasma cholesterol. Overall, myeloid cells do not contribute to IL-10-mediated atheroprotection. In addition, this study demonstrates a novel connection between IL-10-mediated inflammation and cholesterol homeostasis in atherosclerosis. These findings make us reconsider IL-10 as a beneficial influence on atherosclerosis.
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MESH Headings
- Animals
- Apoptosis
- Atherosclerosis/etiology
- Atherosclerosis/metabolism
- Atherosclerosis/prevention & control
- Biological Transport, Active
- Cholesterol/metabolism
- Cholesterol, Dietary/administration & dosage
- Disease Models, Animal
- Female
- Hypercholesterolemia/prevention & control
- Inflammation/etiology
- Inflammation/metabolism
- Inflammation/pathology
- Intestinal Mucosa/metabolism
- Macrophages/metabolism
- Macrophages/pathology
- Mice
- Mice, Knockout
- Myeloid Cells/metabolism
- Myeloid Cells/pathology
- Plaque, Atherosclerotic/etiology
- Plaque, Atherosclerotic/metabolism
- Plaque, Atherosclerotic/pathology
- Receptors, Interleukin-10/deficiency
- Receptors, Interleukin-10/genetics
- Receptors, LDL/deficiency
- Receptors, LDL/genetics
- Signal Transduction
- Sterol O-Acyltransferase/metabolism
- Sterol O-Acyltransferase 2
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Menno P J de Winther
- Prof. M. P. J. de Winther, PhD, Experimental Vascular Biology, Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands, Tel.: +31 20 5666762, E-mail:
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Uto-Kondo H, Ayaori M, Sotherden GM, Nakaya K, Sasaki M, Yogo M, Komatsu T, Takiguchi S, Yakushiji E, Ogura M, Nishida T, Endo Y, Ikewaki K. Ezetimibe enhances macrophage reverse cholesterol transport in hamsters: contribution of hepato-biliary pathway. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1247-55. [PMID: 24989153 DOI: 10.1016/j.bbalip.2014.05.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/13/2014] [Accepted: 05/27/2014] [Indexed: 11/15/2022]
Abstract
Reverse cholesterol transport (RCT) is pivotal in the return of excess cholesterol from peripheral tissues to the liver for excretion in bile and eventually feces. RCT from macrophages is a critical anti-atherogenicity mechanism of HDL. As the cholesterol absorption inhibitor ezetimibe promoted RCT in mice, which lack cholesterol ester transfer protein (CETP), we investigated its effects in hamsters, which have CETP. A high-cholesterol diet (HC) increased cholesterol levels throughout lipoprotein fractions and ezetimibe markedly reduced VLDL/LDL cholesterol levels under both normal chow (NC) and HC. However, ezetimibe did not affect and reduced HDL-cholesterol levels under NC and HC, respectively. Intraperitoneal injection of (3)H-cholesterol pre-labeled macrophages in an in vivo RCT assay increased tracer accumulation in the liver but reduced it in bile under HC, and these changes were completely cancelled by ezetimibe. Under both NC and HC, ezetimibe reduced tracer levels in the liver but increased them in feces, indicating promotion of RCT in vivo. We performed a RCT assay using hamsters subjected to bile duct ligation (BDL) to clarify whether a transintestinal cholesterol efflux (TICE) pathway contributes to ezetimibe's enhancement of RCT. BDL markedly inhibited macrophage-derived (3)H-cholesterol excretion to feces and cancelled ezetimibe's stimulatory effect on RCT, suggesting that biliary cholesterol excretion is a major contributor in RCT promotion by ezetimibe but the contribution of the TICE pathway is minimal. In conclusions, ezetimibe exerts an additive anti-atherogenic property by enhancing RCT in hamsters. Our findings suggest that this property is independent of the TICE pathway.
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Affiliation(s)
- Harumi Uto-Kondo
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Makoto Ayaori
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
| | - Grace Megumi Sotherden
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Kazuhiro Nakaya
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Makoto Sasaki
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Makiko Yogo
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Tomohiro Komatsu
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Shunichi Takiguchi
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Emi Yakushiji
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Masatsune Ogura
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Takafumi Nishida
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Yasuhiro Endo
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
| | - Katsunori Ikewaki
- Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan
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Groen AK, Bloks VW, Verkade H, Kuipers F. Cross-talk between liver and intestine in control of cholesterol and energy homeostasis. Mol Aspects Med. 2014;37:77-88. [PMID: 24560594 DOI: 10.1016/j.mam.2014.02.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 12/04/2013] [Accepted: 02/10/2014] [Indexed: 12/19/2022]
Abstract
A major hurdle for organisms to dispose of cholesterol is the inability to degrade the sterol nucleus which constitutes the central part of the molecule. Synthesis of the sterol nucleus requires a complex, energy costly, metabolic pathway but also generates a diverse array of intermediates serving crucial roles in cellular energy metabolism and signal transduction. This may be the reason why this complex pathway has survived evolutionary pressure. The only way to get rid of substantial amounts of cholesterol is conversion into bile acid or direct excretion of the sterol in the feces. The lack of versatility in disposal mechanisms causes a lack of flexibility to regulate cholesterol homeostasis which may underlie the considerable human pathology linked to cholesterol removal from the body. Export of cholesterol from the body requires an intricate communication between intestine and the liver. The last decade this inter-organ cross talk has been focus of intense research leading to considerable new insight. This novel information on particular the cross-talk between liver and intestine and role of bile acids as signal transducing molecules forms the focus of this review.
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10
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Maïga SF, Kalopissis AD, Chabert M. Apolipoprotein A-II is a key regulatory factor of HDL metabolism as appears from studies with transgenic animals and clinical outcomes. Biochimie 2014; 96:56-66. [PMID: 24012775 DOI: 10.1016/j.biochi.2013.08.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/28/2013] [Indexed: 01/26/2023]
Abstract
The structure and metabolism of HDL are linked to their major apolipoproteins (apo) A-I and A-II. HDL metabolism is very dynamic and depends on the constant remodeling by lipases, lipid transfer proteins and receptors. HDL exert several cardioprotective effects, through their antioxidant and antiinflammatory capacities and through the stimulation of reverse cholesterol transport from extrahepatic tissues to the liver for excretion into bile. HDL also serve as plasma reservoir for C and E apolipoproteins, as transport vehicles for a great variety of proteins, and may have more physiological functions than previously recognized. In this review we will develop several aspects of HDL metabolism with emphasis on the structure/function of apo A-I and apo A-II. An important contribution to our understanding of the respective roles of apo A-I and apo A-II comes from studies using transgenic animal models that highlighted the stabilizatory role of apo A-II on HDL through inhibition of their remodeling by lipases. Clinical studies coupled with proteomic analyses revealed the presence of dysfunctional HDL in patients with cardiovascular disease. Beyond HDL cholesterol, a new notion is the functionality of HDL particles. In spite of abundant literature on HDL metabolic properties, a major question remains unanswered: which HDL particle(s) confer(s) protection against cardiovascular risk?
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