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Huang Z, Zhou RR. Mechanism for FXR to regulate bile acid and glycolipid metabolism to improve NAFLD. Shijie Huaren Xiaohua Zazhi 2023; 31:797-807. [DOI: 10.11569/wcjd.v31.i19.797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/16/2023] [Accepted: 09/21/2023] [Indexed: 10/08/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease, with liver metabolic disorders as major pathological changes, manifested as abnormal lipid accumulation, liver cell oxidative stress, etc., but its etiology is still unclear. The farnesol X receptor (FXR) is a major bile acid receptor in the "gut-liver axis", via which FXR regulates metabolism and affects the pathophysiological status of various substances through different pathways, thus contributing to the occurrence and development of NAFLD. Therefore, FXR has become a potential therapeutic target for NAFLD. This article reviews the relationship between FXR regulation of bile acid, glucose, and lipid metabolism through the "gut-liver axis" and the occurrence and development of NAFLD, to provide new insights and clues for further research about FXR-based pharmaceutical treatments.
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Affiliation(s)
- Zhi Huang
- Department of Infectious Diseases, Xiangya Hospital, Central South University, Changsha 410000, Hunan Province, China
| | - Rong-Rong Zhou
- Department of Infectious Diseases, Xiangya Hospital, Central South University, Changsha 410000, Hunan Province, China
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2
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Yu H. HDL and Scavenger Receptor Class B Type I (SRBI). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1377:79-93. [DOI: 10.1007/978-981-19-1592-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Wang D, Huang J, Gui T, Yang Y, Feng T, Tzvetkov NT, Xu T, Gai Z, Zhou Y, Zhang J, Atanasov AG. SR-BI as a target of natural products and its significance in cancer. Semin Cancer Biol 2020; 80:18-38. [PMID: 31935456 DOI: 10.1016/j.semcancer.2019.12.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/25/2019] [Accepted: 12/30/2019] [Indexed: 02/07/2023]
Abstract
Scavenger receptor class B type I (SR-BI) protein is an integral membrane glycoprotein. SR-BI is emerging as a multifunctional protein, which regulates autophagy, efferocytosis, cell survival and inflammation. It is well known that SR-BI plays a critical role in lipoprotein metabolism by mediating cholesteryl esters selective uptake and the bi-directional flux of free cholesterol. Recently, SR-BI has also been identified as a potential marker for cancer diagnosis, prognosis, or even a treatment target. Natural products are a promising source for the discovery of new drug leads. Multiple natural products were identified to regulate SR-BI protein expression. There are still a number of challenges in modulating SR-BI expression in cancer and in using natural products for modulation of such protein expression. In this review, our purpose is to discuss the relationship between SR-BI protein and cancer, and the molecular mechanisms regulating SR-BI expression, as well as to provide an overview of natural products that regulate SR-BI expression.
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Affiliation(s)
- Dongdong Wang
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Fei Shan Jie 32, 550003, Guiyang, China
| | - Jiansheng Huang
- Department of Medicine, Vanderbilt University Medical Center, 318 Preston Research Building, 2200 Pierce Avenue, Nashville, Tennessee, 37232, USA
| | - Ting Gui
- Key Laboratory of Traditional Chinese Medicine for Classical Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Yaxin Yang
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Fei Shan Jie 32, 550003, Guiyang, China
| | - Tingting Feng
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine, Huaxi university town, 550025, Guiyang, China
| | - Nikolay T Tzvetkov
- Department of Biochemical Pharmacology and Drug Design, Institute of Molecular Biology "Roumen Tsanev", Bulgarian Academy of Sciences, 21 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
| | - Tao Xu
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Fei Shan Jie 32, 550003, Guiyang, China
| | - Zhibo Gai
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Ying Zhou
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine, Huaxi university town, 550025, Guiyang, China.
| | - Jingjie Zhang
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Fei Shan Jie 32, 550003, Guiyang, China.
| | - Atanas G Atanasov
- Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, 05-552, Jastrzębiec, Poland; Department of Pharmacognosy, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria; Institute of Neurobiology, Bulgarian Academy of Sciences, 23 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria; Ludwig Boltzmann Institute for Digital Health and Patient Safety, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria.
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4
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Wang D, Yang Y, Lei Y, Tzvetkov NT, Liu X, Yeung AWK, Xu S, Atanasov AG. Targeting Foam Cell Formation in Atherosclerosis: Therapeutic Potential of Natural Products. Pharmacol Rev 2019; 71:596-670. [PMID: 31554644 DOI: 10.1124/pr.118.017178] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Foam cell formation and further accumulation in the subendothelial space of the vascular wall is a hallmark of atherosclerotic lesions. Targeting foam cell formation in the atherosclerotic lesions can be a promising approach to treat and prevent atherosclerosis. The formation of foam cells is determined by the balanced effects of three major interrelated biologic processes, including lipid uptake, cholesterol esterification, and cholesterol efflux. Natural products are a promising source for new lead structures. Multiple natural products and pharmaceutical agents can inhibit foam cell formation and thus exhibit antiatherosclerotic capacity by suppressing lipid uptake, cholesterol esterification, and/or promoting cholesterol ester hydrolysis and cholesterol efflux. This review summarizes recent findings on these three biologic processes and natural products with demonstrated potential to target such processes. Discussed also are potential future directions for studying the mechanisms of foam cell formation and the development of foam cell-targeted therapeutic strategies.
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Affiliation(s)
- Dongdong Wang
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Yang Yang
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Yingnan Lei
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Nikolay T Tzvetkov
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Xingde Liu
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Andy Wai Kan Yeung
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Suowen Xu
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
| | - Atanas G Atanasov
- The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, China (D.W., X.L.); Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzębiec, Poland (D.W., Y.Y., Y.L., A.G.A.); Department of Pharmacognosy, University of Vienna, Vienna, Austria (A.G.A.); Institute of Clinical Chemistry, University Hospital Zurich, Schlieren, Switzerland (D.W.); Institute of Molecular Biology "Roumen Tsanev," Department of Biochemical Pharmacology and Drug Design, Bulgarian Academy of Sciences, Sofia, Bulgaria (N.T.T.); Pharmaceutical Institute, University of Bonn, Bonn, Germany (N.T.T.); Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York (S.X.); Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (A.W.K.Y.); and Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria (A.G.A.)
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Baldwin WS. Phase 0 of the Xenobiotic Response: Nuclear Receptors and Other Transcription Factors as a First Step in Protection from Xenobiotics. NUCLEAR RECEPTOR RESEARCH 2019; 6:101447. [PMID: 31815118 PMCID: PMC6897393 DOI: 10.32527/2019/101447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This mini-review examines the crucial importance of transcription factors as a first line of defense in the detoxication of xenobiotics. Key transcription factors that recognize xenobiotics or xenobiotic-induced stress such as reactive oxygen species (ROS), include AhR, PXR, CAR, MTF, Nrf2, NF-κB, and AP-1. These transcription factors constitute a significant portion of the pathways induced by toxicants as they regulate phase I-III detoxication enzymes and transporters as well as other protective proteins such as heat shock proteins, chaperones, and anti-oxidants. Because they are often the first line of defense and induce phase I-III metabolism, could these transcription factors be considered the phase 0 of xenobiotic response?
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Affiliation(s)
- William S Baldwin
- Clemson University, Biological Sciences/Environmental Toxicology, 132 Long Hall, Clemson, SC 29634
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6
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Wu ZY, Li H, Li JR, Lv XQ, Jiang JD, Peng ZG. Farnesoid X receptor agonist GW4064 indirectly inhibits HCV entry into cells via down-regulating scavenger receptor class B type I. Eur J Pharmacol 2019; 853:111-120. [PMID: 30902657 DOI: 10.1016/j.ejphar.2019.03.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 03/08/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023]
Abstract
Farnesoid X receptor (FXR) agonists play important regulatory roles in bile acid, lipid and glucose metabolism in vitro and in vivo. Thus, FXR agonists exhibit potential therapeutic effects on metabolism-related diseases that are associated with extrahepatic manifestations induced by hepatitis C virus (HCV) infection. This study investigated the effect and mechanism of FXR agonist GW4064 against HCV in vitro to explore the potential application of FXR agonists. Results showed that GW4064 and other FXR agonists have potent antiviral activity against HCV in Huh7.5 cells. GW4064 down-regulated the expression of scavenger receptor class B type I protein via FXR and thereby indirectly inhibited HCV entry into cells, leading to interruption of HCV life cycle. GW4064 also exhibited synergistic anti-HCV effect with known direct-acting antiviral agents (DAAs) used in the clinic and remained sensitive to DAA-resistant HCV mutations. Therefore, FXR agonists are also a kind of antiviral agent, and might be helpful in treatment of HCV-induced hepatic and extrahepatic manifestations.
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Affiliation(s)
- Zhou-Yi Wu
- Laboratory of Antiviral Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Hu Li
- Laboratory of Antiviral Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jian-Rui Li
- Laboratory of Antiviral Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China; Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Xiao-Qin Lv
- Laboratory of Antiviral Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jian-Dong Jiang
- Laboratory of Antiviral Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China; Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China; State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Zong-Gen Peng
- Laboratory of Antiviral Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China; Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China; Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
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7
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van Niekerk G, Davis T, de Villiers W, Engelbrecht AM. The role of bile acids in nutritional support. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2018; 22:231. [PMID: 30268137 PMCID: PMC6164178 DOI: 10.1186/s13054-018-2160-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022]
Abstract
Nutritional support continues to receive much attention as a possible intervention to prevent loss of lean tissue mass, promote recovery and re-establish proper immune function in critical care patients. Yet there remains much controversy regarding the clinical efficacy of such interventions. In addition to the direct effect of nutrition in terms of micro- and macronutrient content, nutritional formulations may exert an effect via the physiological response to feeding. Here, we highlight the key role of postprandial reabsorbed bile acids in attenuating both the inflammatory response and autophagy. These observations suggest that not all patients would benefit from aggressive nutritional support.
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Affiliation(s)
- Gustav van Niekerk
- Stellenbosch University, Stellenbosch Central, Stellenbosch, 7599, South Africa.
| | - Tanja Davis
- Stellenbosch University, Stellenbosch Central, Stellenbosch, 7599, South Africa
| | - Willem de Villiers
- Stellenbosch University, Stellenbosch Central, Stellenbosch, 7599, South Africa
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Ren K, Jiang T, Zhao GJ. Quercetin induces the selective uptake of HDL-cholesterol via promoting SR-BI expression and the activation of the PPARγ/LXRα pathway. Food Funct 2018; 9:624-635. [PMID: 29292466 DOI: 10.1039/c7fo01107e] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Reverse cholesterol transport (RCT) is the process to deliver cholesterol to the liver for further excretion and involves scavenger receptor class B type I (SR-BI)-mediated selective lipid uptake (SLU) from high-density lipoprotein cholesterol (HDL-C). The up-regulation of hepatic SR-BI expression accelerates HDL-C clearance in circulation and impedes the development of atherosclerosis (AS). In the present study, we explored the modulation of hepatic SR-BI expression and SR-BI-mediated SLU by quercetin, a natural flavonoid compound in the diet with a favorable role in cardiovascular disorders. We found that quercetin significantly increased the expression level of SR-BI in HepG2 cells in a concentration- and time-dependent manner. Besides, quercetin had stimulatory effects on the binding of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil)-labeled HDL to hepatocytes and 125I/3H-CE-HDL association. Treatment with small interfering RNA (siRNA) or SR-BI specific inhibitor, BLT-1, inhibited quercetin-induced Dil-HDL binding and selective HDL-C uptake. Treatment with quercetin increased both proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) levels. Additionally, the quercetin-induced expression of SR-BI, Dil-HDL binding and the selective uptake of HDL-C were significantly attenuated by treatment with PPARγ siRNA, LXRα siRNA, and their antagonists, respectively. In C57BL/6 mice, quercetin administration potently increased SR-BI, PPARγ and LXRα levels and lipid accumulation in the liver. Altogether, our results suggest that quercetin-induced up-regulation of SR-BI and subsequent lipid uptake in hepatocytes might contribute to its beneficial effects on cholesterol homeostasis and atherogenesis.
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Affiliation(s)
- Kun Ren
- Department of Histology and Embryology, Guilin Medical University, Guilin, Guangxi 541004, China.
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Miyahara Y, Bessho K, Kondou H, Hasegawa Y, Yasuda K, Ida S, Ihara Y, Mizuta K, Miyoshi Y, Ozono K. Negative feedback loop of cholesterol regulation is impaired in the livers of patients with Alagille syndrome. Clin Chim Acta 2015; 440:49-54. [PMID: 25444747 DOI: 10.1016/j.cca.2014.10.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 10/06/2014] [Accepted: 10/24/2014] [Indexed: 10/24/2022]
Abstract
AIM To characterize cholesterol regulation in the liver of patients with Alagille syndrome (AGS). METHODS Serum total cholesterol (TC) and total bile acid (TBA) levels were measured in 23 AGS patients. The expressions of genes involved in cholesterol regulation, including low-density lipoprotein receptor (LDLR), scavenger receptor class B type I (SR-BI), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), cholesterol 7α-hydroxylase (CYP7A1), ATP-binding cassette transporter (ABC) A1, and ABCG1/5/8, were measured in liver tissues from five of these patients. Expression of regulators for these genes, including farnesoid X receptor/small heterodimer partner (SHP), liver X receptor α (LXRα) and mature Sterol regulatory element-binding protein 2 (SREBP2) was measured. The expression of mature SREBP2 protein was also examined. RESULTS Serum TC and TBA levels were correlated in the AGS patients. Liver cholesterol was also increased compared with controls, and correlated with bile acid contents. LDLR, SR-BI, HMGCR, and ABCGs mRNA expression were upregulated, while CYP7A1 mRNA expression was downregulated in AGS livers. SHP and LXRα mRNA expression was also increased, but maturation of SREBP2 was not suppressed in the patients. CONCLUSIONS The major upregulators of liver cholesterol might be increased in AGS patients, indicating an impaired negative feedback mechanism and accelerated liver cholesterol accumulation.
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Affiliation(s)
- Yuki Miyahara
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita City, Osaka, Japan
| | - Kazuhiko Bessho
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita City, Osaka, Japan
| | - Hiroki Kondou
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita City, Osaka, Japan.
| | - Yasuhiro Hasegawa
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita City, Osaka, Japan
| | - Kie Yasuda
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita City, Osaka, Japan
| | - Shinobu Ida
- Department of Pediatric Gastroenterology, Nutrition and Endocrinology, Osaka Medical Center and Research Institute for Maternal and Child Health, 840 Murodou, Izumi City, Osaka, Japan
| | - Yoshiyuki Ihara
- Department of Transplant Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke City, Tochigi, Japan
| | - Koichi Mizuta
- Department of Transplant Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke City, Tochigi, Japan
| | - Yoko Miyoshi
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita City, Osaka, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita City, Osaka, Japan
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10
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Kardassis D, Gafencu A, Zannis VI, Davalos A. Regulation of HDL genes: transcriptional, posttranscriptional, and posttranslational. Handb Exp Pharmacol 2015; 224:113-179. [PMID: 25522987 DOI: 10.1007/978-3-319-09665-0_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
HDL regulation is exerted at multiple levels including regulation at the level of transcription initiation by transcription factors and signal transduction cascades; regulation at the posttranscriptional level by microRNAs and other noncoding RNAs which bind to the coding or noncoding regions of HDL genes regulating mRNA stability and translation; as well as regulation at the posttranslational level by protein modifications, intracellular trafficking, and degradation. The above mechanisms have drastic effects on several HDL-mediated processes including HDL biogenesis, remodeling, cholesterol efflux and uptake, as well as atheroprotective functions on the cells of the arterial wall. The emphasis is on mechanisms that operate in physiologically relevant tissues such as the liver (which accounts for 80% of the total HDL-C levels in the plasma), the macrophages, the adrenals, and the endothelium. Transcription factors that have a significant impact on HDL regulation such as hormone nuclear receptors and hepatocyte nuclear factors are extensively discussed both in terms of gene promoter recognition and regulation but also in terms of their impact on plasma HDL levels as was revealed by knockout studies. Understanding the different modes of regulation of this complex lipoprotein may provide useful insights for the development of novel HDL-raising therapies that could be used to fight against atherosclerosis which is the underlying cause of coronary heart disease.
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Affiliation(s)
- Dimitris Kardassis
- Department of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology of Hellas, Heraklion, Crete, 71110, Greece,
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11
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Xu JY, Li ZP, Zhang L, Ji G. Recent insights into farnesoid X receptor in non-alcoholic fatty liver disease. World J Gastroenterol 2014; 20:13493-13500. [PMID: 25309079 PMCID: PMC4188900 DOI: 10.3748/wjg.v20.i37.13493] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 05/22/2014] [Accepted: 06/26/2014] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome and is one of the most prevalent liver disorders worldwide. NAFLD can gradually progress to liver inflammation, fibrosis, cirrhosis and even hepatocellular carcinoma. However, the pathogenesis of NAFLD is complex, and no efficient pharmaceutic treatments have yet been established for NAFLD. Accumulating data have shown that the farnesoid X receptor (FXR) plays important roles not only in bile acid metabolism, but also in lipid and carbohydrate homeostasis, inflammatory responses, among others. In this review, we aim to highlight the role of FXR in the pathogenesis and treatment of NAFLD.
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Bile acids reduce endocytosis of high-density lipoprotein (HDL) in HepG2 cells. PLoS One 2014; 9:e102026. [PMID: 25010412 PMCID: PMC4092120 DOI: 10.1371/journal.pone.0102026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 06/13/2014] [Indexed: 02/06/2023] Open
Abstract
High-density lipoprotein (HDL) transports lipids to hepatic cells and the majority of HDL-associated cholesterol is destined for biliary excretion. Cholesterol is excreted into the bile directly or after conversion to bile acids, which are also present in the plasma as they are effectively reabsorbed through the enterohepatic cycle. Here, we provide evidence that bile acids affect HDL endocytosis. Using fluorescent and radiolabeled HDL, we show that HDL endocytosis was reduced in the presence of high concentrations of taurocholate, a natural non-cell-permeable bile acid, in human hepatic HepG2 and HuH7 cells. In contrast, selective cholesteryl-ester (CE) uptake was increased. Taurocholate exerted these effects extracellularly and independently of HDL modification, cell membrane perturbation or blocking of endocytic trafficking. Instead, this reduction of endocytosis and increase in selective uptake was dependent on SR-BI. In addition, cell-permeable bile acids reduced HDL endocytosis by farnesoid X receptor (FXR) activation: chenodeoxycholate and the non-steroidal FXR agonist GW4064 reduced HDL endocytosis, whereas selective CE uptake was unaltered. Reduced HDL endocytosis by FXR activation was independent of SR-BI and was likely mediated by impaired expression of the scavenger receptor cluster of differentiation 36 (CD36). Taken together we have shown that bile acids reduce HDL endocytosis by transcriptional and non-transcriptional mechanisms. Further, we suggest that HDL endocytosis and selective lipid uptake are not necessarily tightly linked to each other.
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Amano Y, Shimada M, Miura S, Adachi R, Tozawa R. Effects of a farnesoid X receptor antagonist on hepatic lipid metabolism in primates. Eur J Pharmacol 2013; 723:108-15. [PMID: 24361308 DOI: 10.1016/j.ejphar.2013.10.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 10/02/2013] [Accepted: 10/20/2013] [Indexed: 01/22/2023]
Abstract
We aimed to elucidate the mechanism underlying the anti-dyslipidemic effect of compound-T3, a farnesoid X receptor antagonist, by investigating its effects on hepatic lipid metabolism in non-human primates. We administered lipid-lowering drugs for 7 days to cynomolgus monkeys receiving a high-fat diet, and subsequently measured the levels of lipid parameters in plasma, feces, and hepatic tissue fluids. Compound-T3 (0.3 and 3mg/kg p.o.) significantly decreased the plasma levels of non-high-density lipoprotein (non-HDL) cholesterol and apolipoprotein B in a dose-dependent manner. It also decreased the mRNA levels of hepatic small heterodimer partner-1, induced the mRNA expression of hepatic cholesterol 7α-hydroxylase, reduced hepatic cholesterol and triglyceride levels, increased fecal bile acid excretion, and upregulated the expression of hepatic low-density lipoprotein (LDL) receptor. Furthermore, compound-T3 significantly increased plasma HDL cholesterol and apolipoprotein A-I levels. The mRNA expression levels of hepatic apolipoprotein A-I tended to increase after compound-T3 treatment. Compound-T3 also induced accumulation of hepatic bile acids and decreased the mRNA expression levels of the hepatic bile acid export pump. The effects of cholestyramine (300mg/kg p.o.) on the plasma and hepatic lipid parameters were similar to those of compound-T3, and it increased fecal bile acid levels without causing accumulation of hepatic bile acids. These findings suggest that LDL receptor-mediated hepatic LDL incorporation due to cholesterol catabolism catalyzed by cholesterol 7α-hydroxylase decreases plasma non-HDL cholesterol levels. Upregulation of hepatic apolipoprotein A-I mRNA expression may partially contribute to the increase in HDL cholesterol levels mediated by compound-T3.
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Affiliation(s)
- Yuichiro Amano
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1 Muraokahigashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan.
| | - Mitsuyuki Shimada
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1 Muraokahigashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Shotaro Miura
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1 Muraokahigashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Ryutaro Adachi
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1 Muraokahigashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Ryuichi Tozawa
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1 Muraokahigashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
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Gabbi C, Warner M, Gustafsson JÅ. Action mechanisms of Liver X Receptors. Biochem Biophys Res Commun 2013; 446:647-50. [PMID: 24300092 DOI: 10.1016/j.bbrc.2013.11.077] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 11/19/2013] [Indexed: 12/18/2022]
Abstract
The two Liver X Receptors, LXRα and LXRβ, are nuclear receptors belonging to the superfamily of ligand-activated transcription factors. They share more than 78% homology in amino acid sequence, a common profile of oxysterol ligands and the same heterodimerization partner, Retinoid X Receptor. LXRs play crucial roles in several metabolic pathways: lipid metabolism, in particular in preventing cellular cholesterol accumulation; glucose homeostasis; inflammation; central nervous system functions and water transport. As with all nuclear receptors, the transcriptional activity of LXR is the result of an orchestration of numerous cellular factors including ligand bioavailability, presence of corepressors and coactivators and cellular context i.e., what other pathways are activated in the cell at the time the receptor recognizes its ligand. In this mini-review we summarize the factors regulating the transcriptional activity and the mechanisms of action of these two receptors.
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Affiliation(s)
- Chiara Gabbi
- Center for Nuclear Receptors and Cell Signaling, University of Houston, 3056 Cullen Blv, 77204 Houston, Texas, USA
| | - Margaret Warner
- Center for Nuclear Receptors and Cell Signaling, University of Houston, 3056 Cullen Blv, 77204 Houston, Texas, USA
| | - Jan-Åke Gustafsson
- Center for Nuclear Receptors and Cell Signaling, University of Houston, 3056 Cullen Blv, 77204 Houston, Texas, USA; Department of Biosciences and Nutrition, Karolinska Institutet, Novum S-141 86, Sweden.
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Atkin SD, Owen BM, Bookout AL, Cravo RM, Lee C, Elias CF, Elmquist JK, Kliewer SA, Mangelsdorf DJ. Nuclear receptor LRH-1 induces the reproductive neuropeptide kisspeptin in the hypothalamus. Mol Endocrinol 2013; 27:598-605. [PMID: 23504956 PMCID: PMC3607696 DOI: 10.1210/me.2012-1371] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 01/31/2013] [Indexed: 02/07/2023] Open
Abstract
The differential expression and secretion of the neuropeptide kisspeptin from neurons in the arcuate (Arc) and anteroventral periventricular (AVPV) nuclei of the hypothalamus coordinate the temporal release of pituitary gonadotropins that control the female reproductive cycle. However, the molecular basis for this differential regulation is incompletely understood. Here, we report that liver receptor homolog-1 (LRH-1), a member of the nuclear receptor superfamily, is expressed in kisspeptin neurons in the Arc but not in the AVPV in female mice. LRH-1 binds directly to the kisspeptin (Kiss1) promoter and stimulates Kiss1 transcription. Deletion of LRH-1 from kisspeptin neurons in mice decreased Kiss1 expression in the Arc, leading to reduced plasma FSH levels, dysregulated follicle maturation, and prolongation of the estrous cycle. Conversely, overexpression of LRH-1 in kisspeptin neurons increased Arc Kiss1 expression and plasma FSH concentrations. These studies provide a molecular basis for the differential regulation of basal kisspeptin expression in Arc and AVPV neurons and reveal a prominent role for LRH-1 in hypothalamus in regulating the female reproductive axis.
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Affiliation(s)
- Stan D Atkin
- Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Room ND9.124, Dallas, Texas 75390-9041, USA
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Synthetic FXR agonist GW4064 prevents diet-induced hepatic steatosis and insulin resistance. Pharm Res 2013; 30:1447-57. [PMID: 23371517 DOI: 10.1007/s11095-013-0986-7] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 01/14/2013] [Indexed: 02/08/2023]
Abstract
PURPOSE To examine the effect of farnesoid X receptor (FXR) activation by its synthetic agonist, 3-[2-[2-Chloro-4-[[3-(2,6-dichlorophenyl)-5-(1-methylethyl)-4-isoxazolyl]methoxy]phenyl]ethenyl]benzoic acid (GW4064) on diet-induced obesity and hepatic steatosis. METHODS Fifteen week-old C57BL/6 mice fed with high-fat diet (HFD) or high-fat, high-cholesterol diet were treated by twice weekly injection of GW4064 (50 mg/kg) intraperitoneally or DMSO (carrier solution) for 6 weeks. Body weight, body composition and food intake were monitored weekly. Serum glucose and insulin levels and lipid content in the liver were measured at the end of study. Additionally, genes involved in lipogenesis, gluconeogenesis and inflammation were analyzed by real time PCR. CD36 protein level was detected by western blot. RESULTS Activation of FXR by GW4064 suppressed weight gain in C57BL/6 mice fed with either HFD or high-fat and high-cholesterol diet. GW4064 treatment of mice significantly repressed diet-induced hepatic steatosis as evidenced by lower triglyceride and free fatty acid level in the liver. Analysis of genes involved in lipid metabolism showed GW4064 markedly reduced lipid transporter Cd36 gene expression without affecting expression of genes that are directly involved in lipogenesis. GW4064 treatment attenuated hepatic inflammation while having no effect on white adipose tissue. In addition, activation of FXR by GW4064 avoided diet-induced hyperinsulinemia and hyperglycemia through decreasing the transcript levels of phosphoenolpyruvate carboxykinase (Pepck) and glucose-6-phosphatase (G6pase), two key enzymes in gluconeogenesis. CONCLUSIONS The results verify the important function of FXR in diet-induced obesity and suggest that FXR agonists are promising therapeutic agents for obesity-associated metabolic disorders.
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Direct effect of chenodeoxycholic acid on differentiation of mouse embryonic stem cells cultured under feeder-free culture conditions. BIOMED RESEARCH INTERNATIONAL 2012; 2013:375076. [PMID: 23509715 PMCID: PMC3591134 DOI: 10.1155/2013/375076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/18/2012] [Accepted: 10/21/2012] [Indexed: 01/11/2023]
Abstract
Chenodeoxycholic acid (CDCA), a farnesoid X receptor (FXR) ligand, is a member of the nuclear receptor family and is probably involved in regulating the cellular activities of embryonic stem (ES) cells. Recently, although it was reported that the FXR ligand can mediate differentiation, apoptosis, and/or growth arrest in several cell types, it is still not well known how CDCA mediates effects in ES cells. Therefore, we investigated the direct effect of CDCA on mES cells. Feeder-free mES cells were treated in a dose-dependent manner with CDCA (50, 100, and 200 μM) for 72 h, and then a 100 μM CDCA treatment was performed for an additional 72 h. We analyzed the morphology, cell growth, cell characteristics, immunocytochemistry, and RT-PCR. In CDCA-treated cells, we observed the disappearance of pluripotent stem cell markers including alkaline phosphatase, Oct4, and Nanog and a time- and dose-dependent increase in expression of nestin, PAX6, and α-smooth muscle actin, but not α-fetoprotein. The 100 μM CDCA-treated cells in their second passage continued this differentiation pattern similar to those in the controls. In conclusion, these results suggest that CDCA can guide mES cells by an FXR-independent pathway to differentiate into ectoderm and/or mesoderm, but not endoderm.
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Abstract
Farnesoid x receptor (FXR) is a ligand-dependent nuclear transcription factor, belonging to the nuclear receptor superfamily. It is activated by bile acids (BAs) and is expressed in the liver, intestine, kidney, and adrenal gland. Upon activation by endogenous ligand (BAs), FXR can regulate triglyceride (TG) metabolism by modulating the activity of related enzymes, lipoprotein and receptors, and maintaining the balance between the contents of TG in the liver and circulation. This review aims to elucidate the regulation of triglyceride metabolism by FXR.
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Li G, Thomas AM, Williams JA, Kong B, Liu J, Inaba Y, Xie W, Guo GL. Farnesoid X receptor induces murine scavenger receptor Class B type I via intron binding. PLoS One 2012; 7:e35895. [PMID: 22540009 PMCID: PMC3335076 DOI: 10.1371/journal.pone.0035895] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 03/23/2012] [Indexed: 12/22/2022] Open
Abstract
Farnesoid X receptor (FXR) is a nuclear receptor and a key regulator of liver cholesterol and triglyceride homeostasis. Scavenger receptor class B type I (SR-BI) is critical for reverse cholesterol transport (RCT) by transporting high-density lipoprotein (HDL) into liver. FXR induces SR-BI, however, the underlying molecular mechanism of this induction is not known. The current study confirmed induction of SR-BI mRNA by activated FXR in mouse livers, a human hepatoma cell line, and primary human hepatocytes. Genome-wide FXR binding analysis in mouse livers identified 4 putative FXR response elements in the form of inverse repeat separated by one nucleotide (IR1) at the first intron and 1 IR1 at the downstream of the mouse Sr-bi gene. ChIP-qPCR analysis revealed FXR binding to only the intronic IR1s, but not the downstream one. Luciferase assays and site-directed mutagenesis further showed that 3 out of 4 IR1s were able to activate gene transcription. A 16-week high-fat diet (HFD) feeding in mice increased hepatic Sr-bi gene expression in a FXR-dependent manner. In addition, FXR bound to the 3 bona fide IR1s in vivo, which was increased following HFD feeding. Serum total and HDL cholesterol levels were increased in FXR knockout mice fed the HFD, compared to wild-type mice. In conclusion, the Sr-bi/SR-BI gene is confirmed as a FXR target gene in both mice and humans, and at least in mice, induction of Sr-bi by FXR is via binding to intronic IR1s. This study suggests that FXR may serve as a promising molecular target for increasing reverse cholesterol transport.
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MESH Headings
- Animals
- Base Sequence
- Cells, Cultured
- Cholesterol/metabolism
- Diet, High-Fat
- Female
- Hep G2 Cells
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Humans
- Introns
- Isoxazoles/pharmacology
- Lipoproteins, HDL/metabolism
- Liver/drug effects
- Liver/metabolism
- Mice
- Mice, Inbred C57BL
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/deficiency
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Scavenger Receptors, Class B/genetics
- Scavenger Receptors, Class B/metabolism
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Affiliation(s)
- Guodong Li
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Department of Abdominal Surgery, Cancer Treatment Center, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China
| | - Ann M. Thomas
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Jessica A. Williams
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Bo Kong
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Jie Liu
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Yuka Inaba
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Wen Xie
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Grace L. Guo
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- * E-mail:
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Lipoprotein distribution and serum concentrations of 7α-hydroxy-4-cholesten-3-one and bile acids: effects of monogenic disturbances in high-density lipoprotein metabolism. Clin Sci (Lond) 2012; 122:385-96. [PMID: 22010943 DOI: 10.1042/cs20110482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BA (bile acid) formation is considered an important final step in RCT (reverse cholesterol transport). HDL (high-density lipoprotein) has been reported to transport BAs. We therefore investigated the effects of monogenic disturbances in human HDL metabolism on serum concentrations and lipoprotein distributions of the major 15 BA species and their precursor C4 (7α-hydroxy-4-cholesten-3-one). In normolipidaemic plasma, approximately 84%, 11% and 5% of BAs were recovered in the LPDS (lipoprotein-depleted serum), HDL and the combined LDL (low-density lipoprotein)/VLDL (very-low-density lipoproteins) fraction respectively. Conjugated BAs were slightly over-represented in HDL. For C4, the respective percentages were 23%, 21% and 56% (41% in LDL and 15% in VLDL) respectively. Compared with unaffected family members, neither HDL-C (HDL-cholesterol)-decreasing mutations in the genes APOA1 [encoding ApoA-I (apolipoprotein A-I], ABCA1 (ATP-binding cassette transporter A1) or LCAT (lecithin:cholesterol acyltransferase) nor HDL-C-increasing mutations in the genes CETP (cholesteryl ester transfer protein) or LIPC (hepatic lipase) were associated with significantly different serum concentrations of BA and C4. Plasma concentrations of conjugated and secondary BAs differed between heterozygous carriers of SCARB1 (scavenger receptor class B1) mutations and unaffected individuals (P<0.05), but this difference was not significant after correction for multiple testing. Moreover, no differences in the lipoprotein distribution of BAs in the LPDS and HDL fractions from SCARB1 heterozygotes were observed. In conclusion, despite significant recoveries of BAs and C4 in HDL and despite the metabolic relationships between RCT and BA formation, monogenic disorders of HDL metabolism do not lead to altered serum concentrations of BAs and C4.
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Mechanisms regulating hepatic SR-BI expression and their impact on HDL metabolism. Atherosclerosis 2011; 217:299-307. [DOI: 10.1016/j.atherosclerosis.2011.05.036] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 05/11/2011] [Accepted: 05/26/2011] [Indexed: 11/22/2022]
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Davidson MH. Therapies targeting exogenous cholesterol uptake: new insights and controversies. Curr Atheroscler Rep 2011; 13:95-100. [PMID: 21188557 DOI: 10.1007/s11883-010-0151-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Exogenous cholesterol uptake involves a complex process in the intestines for the absorption of cholesterol and bile acids. This process is regulated by intestinal nuclear transcription factors such as LXR that affect sterol transporters NPC1L1, ABCG5/G8, and ABCG1, and enzymes such as ACAT-2. Plant sterol/stanols, ezetimibe, and bile acid sequestrants have a variety of effects on these various transporters, and new insights into their mechanism(s) of action have provided a plethora of exciting targets for metabolic diseases, dyslipidemia, and atherosclerosis.
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Affiliation(s)
- Michael H Davidson
- Clinical Professor, Director of Preventive Cardiology, The University of Chicago Pritzker School of Medicine, 515 North State Street, Suite 2700, Chicago, IL 60654, USA.
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Chao F, Gong W, Zheng Y, Li Y, Huang G, Gao M, Li J, Kuruba R, Gao X, Li S, He F. Upregulation of scavenger receptor class B type I expression by activation of FXR in hepatocyte. Atherosclerosis 2010; 213:443-8. [DOI: 10.1016/j.atherosclerosis.2010.09.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 09/15/2010] [Accepted: 09/15/2010] [Indexed: 12/20/2022]
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Lecker JL, Matthan NR, Billheimer JT, Rader DJ, Lichtenstein AH. Impact of dietary fat type within the context of altered cholesterol homeostasis on cholesterol and lipoprotein metabolism in the F1B hamster. Metabolism 2010; 59:1491-501. [PMID: 20197195 PMCID: PMC2891578 DOI: 10.1016/j.metabol.2010.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Revised: 12/21/2009] [Accepted: 01/19/2010] [Indexed: 01/25/2023]
Abstract
Cholesterol status and dietary fat alter several metabolic pathways reflected in lipoprotein profiles. To assess plasma lipoprotein response and mechanisms by which cholesterol and dietary fat type regulate expression of genes involved in lipoprotein metabolism, we developed an experimental model system using F1B hamsters fed diets (12 weeks) enriched in 10% (wt/wt) coconut, olive, or safflower oil with either high cholesterol (0.1%; cholesterol supplemented) or low cholesterol coupled with cholesterol-lowering drugs 10 days before killing (0.01% cholesterol, 0.15% lovastatin, 2% cholestyramine; cholesterol depleted). Irrespective of dietary fat, cholesterol depletion, relative to supplementation, resulted in lower plasma non-high-density lipoprotein (non-HDL) and HDL cholesterol, and triglyceride concentrations (all Ps < .05). In the liver, these differences were associated with higher sterol regulatory element binding protein-2, low-density lipoprotein receptor, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and 7α-hydroxylase messenger RNA (mRNA) levels; higher scavenger receptor B1 and apolipoprotein A-I mRNA and protein levels; lower apolipoprotein E protein levels; and in intestine, modestly lower sterol transporters adenosine triphosphate-binding cassette (ABC) A1, ABCG5, and ABCG8 mRNA levels. Irrespective of cholesterol status, coconut oil, relative to olive and safflower oils, resulted in higher non-HDL cholesterol and triglyceride concentrations (both Ps < .05) and modestly higher sterol regulatory element binding protein-2 mRNA levels. These data suggest that, in F1B hamsters, differences in plasma lipoprotein profiles in response to cholesterol depletion are associated with changes in the expression of genes involved in cholesterol metabolism, whereas the effect of dietary fat type on gene expression was modest, which limits the usefulness of the experimental animal model.
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Affiliation(s)
- Jaime L. Lecker
- Cardiovascular Nutrition Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston MA
| | - Nirupa R. Matthan
- Cardiovascular Nutrition Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston MA
| | - Jeffrey T. Billheimer
- Cardiovascular Institute, University of Pennsylvania School of Medicine, Philadelphia PA
| | - Daniel J. Rader
- Cardiovascular Institute, University of Pennsylvania School of Medicine, Philadelphia PA
| | - Alice H. Lichtenstein
- Corresponding author. Alice H. Lichtenstein, DSc., JM USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111. Tel. 617-556-3127.
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Hypocholesterolemic effects of Lactobacillus plantarum KCTC3928 by increased bile acid excretion in C57BL/6 mice. Nutrition 2010; 26:321-30. [DOI: 10.1016/j.nut.2009.04.011] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 04/17/2009] [Accepted: 04/17/2009] [Indexed: 12/19/2022]
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26
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Han KC, Kim JH, Kim KH, Kim EE, Seo JH, Yang EG. Identification of farnesoid X receptor modulators by a fluorescence polarization-based interaction assay. Anal Biochem 2010; 398:185-90. [DOI: 10.1016/j.ab.2009.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 11/05/2009] [Accepted: 11/07/2009] [Indexed: 10/20/2022]
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27
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Krämer S, Testa B. The Biochemistry of Drug Metabolism - An Introduction. Chem Biodivers 2009; 6:1477-660, table of contents. [DOI: 10.1002/cbdv.200900233] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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28
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Lefebvre P, Cariou B, Lien F, Kuipers F, Staels B. Role of bile acids and bile acid receptors in metabolic regulation. Physiol Rev 2009; 89:147-91. [PMID: 19126757 DOI: 10.1152/physrev.00010.2008] [Citation(s) in RCA: 1137] [Impact Index Per Article: 75.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The incidence of the metabolic syndrome has taken epidemic proportions in the past decades, contributing to an increased risk of cardiovascular disease and diabetes. The metabolic syndrome can be defined as a cluster of cardiovascular disease risk factors including visceral obesity, insulin resistance, dyslipidemia, increased blood pressure, and hypercoagulability. The farnesoid X receptor (FXR) belongs to the superfamily of ligand-activated nuclear receptor transcription factors. FXR is activated by bile acids, and FXR-deficient (FXR(-/-)) mice display elevated serum levels of triglycerides and high-density lipoprotein cholesterol, demonstrating a critical role of FXR in lipid metabolism. In an opposite manner, activation of FXR by bile acids (BAs) or nonsteroidal synthetic FXR agonists lowers plasma triglycerides by a mechanism that may involve the repression of hepatic SREBP-1c expression and/or the modulation of glucose-induced lipogenic genes. A cross-talk between BA and glucose metabolism was recently identified, implicating both FXR-dependent and FXR-independent pathways. The first indication for a potential role of FXR in diabetes came from the observation that hepatic FXR expression is reduced in animal models of diabetes. While FXR(-/-) mice display both impaired glucose tolerance and decreased insulin sensitivity, activation of FXR improves hyperglycemia and dyslipidemia in vivo in diabetic mice. Finally, a recent report also indicates that BA may regulate energy expenditure in a FXR-independent manner in mice, via activation of the G protein-coupled receptor TGR5. Taken together, these findings suggest that modulation of FXR activity and BA metabolism may open new attractive pharmacological approaches for the treatment of the metabolic syndrome and type 2 diabetes.
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Affiliation(s)
- Philippe Lefebvre
- Institut National de la Sante et de la Recherche Medicale, Lille, France
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Chanda D, Park JH, Choi HS. Molecular basis of endocrine regulation by orphan nuclear receptor Small Heterodimer Partner. Endocr J 2008; 55:253-68. [PMID: 17984569 DOI: 10.1507/endocrj.k07e-103] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Nuclear receptors (NRs) are a unique superfamily of transcription factors (TFs) which are involved in and play a crucial role in almost all aspects of mammalian physiology. Small Heterodimer Partner (SHP; NR0B2), an exceptional member of this superfamily of NRs, have been identified as a key regulatory factor of the transcription of a variety of genes involved in diverse metabolic pathways, and are thereby an important factor in a variety of physiological functions. Since its discovery a decade ago, considerable progress has been made in the elucidation of the underlying mechanism by which SHP regulates various metabolic processes, and the results of previous studies support its importance in the maintenance of metabolic homeostasis. In this review, we have evaluated the current state of understanding of the molecular mechanisms and the resultant physiological interpretations governed by SHP.
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Affiliation(s)
- Dipanjan Chanda
- Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
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Park WI, Park MJ, An JK, Choi YH, Kim HY, Cheong J, Yang US. Bile acid regulates c-Jun expression through the orphan nuclear receptor SHP induction in gastric cells. Biochem Biophys Res Commun 2008; 369:437-43. [DOI: 10.1016/j.bbrc.2008.02.065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 02/09/2008] [Indexed: 10/22/2022]
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Nagasaka H, Miida T, Hirano KI, Ota A, Murayama K, Yorifuji T, Kobayashi K, Takatani T, Tsukahara H, Hui SP, Takayanagi M, Chiba H. Fluctuation of lipoprotein metabolism linked with bile acid-activated liver nuclear receptors in Alagille syndrome. Atherosclerosis 2008; 198:434-40. [PMID: 18430427 DOI: 10.1016/j.atherosclerosis.2008.02.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Revised: 02/04/2008] [Accepted: 02/16/2008] [Indexed: 12/14/2022]
Abstract
Alagille syndrome (AGS) is a rare hereditary disorder exhibiting fluctuating cholestasis and dyslipidemia. Farnesoid X receptor (FXR) and liver X receptor (LXR) are hepatic nuclear receptors that regulate bile acid and lipoprotein metabolism. To investigate whether cholestasis is related to dyslipidemia and hepatic nuclear receptor expression in AGS patients, we determined the blood levels of total bile acid (TBA) and lipoprotein parameters, and examined hepatic nuclear receptor expression in three AGS children and their three incomplete AGS parents repeatedly over several years. In the AGS children, TBA level showed significant positive correlations with low-density lipoprotein-cholesterol, apolipoprotein E (apoE)-rich high-density lipoprotein-cholesterol (HDL-C), apoA-I, apoE, and cholesteryl ester transfer protein (CETP) concentrations, but negative correlation with apoE-poor HDL-C concentration. Western blot analysis of liver biopsy specimens revealed that FXR and LXR expression increased in parallel with TBA level. CETP- and ATP-binding cassette transporter A1 expression also increased with TBA level, while scavenger receptor class B type-I expression showed the opposite response. However, apoA-I expression was similar to the control level at any TBA level. In the incomplete AGS parents, TBA and lipoprotein parameters showed little fluctuation. In summary, cholestasis is closely related to dyslipidemia and hepatic nuclear receptor expression in AGS patients.
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Affiliation(s)
- Hironori Nagasaka
- Division of Metabolism, Chiba Children's Hospital, Chiba 266-0007, Japan
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Song X, Kaimal R, Yan B, Deng R. Liver receptor homolog 1 transcriptionally regulates human bile salt export pump expression. J Lipid Res 2008; 49:973-84. [PMID: 18270374 DOI: 10.1194/jlr.m700417-jlr200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The metabolic conversion of cholesterol into bile acids in liver is initiated by the rate-limiting cholesterol 7 alpha-hydroxylase (CYP7A1), whereas the bile salt export pump (BSEP) is responsible for the canalicular secretion of bile acids. Liver receptor homolog 1 (LRH-1) is a key transcriptional factor required for the hepatic expression of CYP7A1. We hypothesized that LRH-1 was also involved in the transcriptional regulation of BSEP. In support of our hypothesis, we found that overexpression of LRH-1 induced, whereas knockdown of LRH-1 decreased, BSEP expression. Consistent with its role in transcriptional regulation, LRH-1 dose-dependently transactivated the BSEP promoter. In addition, such transactivation by LRH-1 was required for maximal induction of BSEP expression through the bile acid/farnesoid X receptor (FXR) activation pathway. Bioinformatic and mutational analysis led to the identification of a functional liver receptor homolog 1-responsive element (LRHRE) in the BSEP promoter. Specific binding of LRH-1 to the LRHRE and recruitment of LRH-1 to the BSEP promoter were demonstrated by electrophoretic mobility shift assay and chromatin immunoprecipitation assay, respectively. In conclusion, LRH-1 transcriptionally activated the BSEP promoter and functioned as a modulator in bile acid/FXR-mediated BSEP regulation. These results suggest that LRH-1 plays a supporting role to FXR in maintaining hepatic bile acid levels by coordinately regulating CYP7A1 and BSEP for bile acid synthesis and elimination, respectively.
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Affiliation(s)
- Xiulong Song
- Department of Biomedical and Pharmaceutical Sciences, Center for Pharmacogenomics and Molecular Therapy, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
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Venteclef N, Haroniti A, Tousaint JJ, Talianidis I, Delerive P. Regulation of anti-atherogenic apolipoprotein M gene expression by the orphan nuclear receptor LRH-1. J Biol Chem 2007; 283:3694-701. [PMID: 17977826 DOI: 10.1074/jbc.m706382200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The orphan nuclear receptor liver receptor homolog-1 (LRH-1, NR5A2) has been reported to play a crucial role in early development, in the control of the hepatic inflammatory response, in intestinal cell crypt renewal as well as in bile acid biosynthesis and reverse cholesterol transport (RCT). Here, we report the identification of apolipoprotein M (APOM) as a novel target gene for LRH-1. Using gene-silencing experiments, adenovirus-mediated overexpression, transient transfection, and chromatin immunoprecipitation (ChIP) assays, it is shown that LRH-1 directly regulates human and mouse APOM transcription by binding to an LRH-1 response element located in the proximal APOM promoter region. In addition, we demonstrate that bile acids suppress APOM expression in a SHP-dependent manner in vitro and in vivo by inhibiting LRH-1 transcriptional activity on the APOM promoter as demonstrated by in vivo ChIP assay. Taken together, our results demonstrate that LRH-1 is a novel regulator of APOM transcription and further extend the role of this orphan nuclear receptor in lipoprotein metabolism and cholesterol homeostasis.
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Affiliation(s)
- Nicolas Venteclef
- Cardiovascular and Urogenital Center of Excellence for Drug Discovery, GlaxoSmithKline, 25 Avenue du Quebec, 91951 Les Ulis, France
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Sporstøl M, Mousavi SA, Eskild W, Roos N, Berg T. ABCA1, ABCG1 and SR-BI: hormonal regulation in primary rat hepatocytes and human cell lines. BMC Mol Biol 2007; 8:5. [PMID: 17241464 PMCID: PMC1790708 DOI: 10.1186/1471-2199-8-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 01/22/2007] [Indexed: 11/18/2022] Open
Abstract
Background Scavenger receptor type B class I (SR-BI), ABC transporter A1 (ABCA1) -and G1 (ABCG1) all play important roles in the reverse cholesterol transport. Reverse cholesterol transport is a mechanism whereby the body can eliminate excess cholesterol. Here, the regulation of SR-BI, ABCA1, and ABCG1 by dexamethasone (a synthetic glucocorticoid) and insulin were studied in order to gain more insight into the role of these two hormones in the cholesterol metabolism. Results By use of real time RT-PCR and Western blotting we examined the expression of our target genes. The results show that SR-BI, ABCA1 and ABCG1 mRNA expression increased in response to dexamethasone while insulin treatment reduced the expression in primary rat hepatocytes. The stimulatory effect of dexamethasone was reduced by the addition of the anti-glucocorticoid mifepristone. In HepG2 cells and THP-1 macrophages, however, the effect of dexamethasone was absent or inhibitory with no significant change in the presence of mifepristone. The latter observation may be a result of the low protein expression of glucocorticoid receptor (GR) in these cell lines. Conclusion Our results illustrates that insulin and glucocorticoids, two hormones crucial in the carbohydrate metabolism, also play an important role in the regulation of genes central in reverse cholesterol transport. We found a marked difference in mRNA expression between the primary cells and the two established cell lines when studying the effect of dexamethasone which may result from the varying expression levels of GR.
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Affiliation(s)
- Marita Sporstøl
- Programme for Cell Biology, Department of Molecular Biosciences, University of Oslo, Norway
| | - Seyed Ali Mousavi
- Programme for Cell Biology, Department of Molecular Biosciences, University of Oslo, Norway
| | - Winnie Eskild
- Programme for Cell Biology, Department of Molecular Biosciences, University of Oslo, Norway
| | - Norbert Roos
- Programme for Cell Biology, Department of Molecular Biosciences, University of Oslo, Norway
| | - Trond Berg
- Programme for Cell Biology, Department of Molecular Biosciences, University of Oslo, Norway
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Lee YS, Chanda D, Sim J, Park YY, Choi HS. Structure and function of the atypical orphan nuclear receptor small heterodimer partner. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 261:117-58. [PMID: 17560281 DOI: 10.1016/s0074-7696(07)61003-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The small heterodimer partner (SHP; NROB2) is a member of the nuclear receptor superfamily and is classified as an "orphan" subgroup, as its ligand has not yet been identified. SHP lacks the classical DNA-binding domain found in most nuclear receptors and functions as a transcriptional coregulator by directly interacting with nuclear receptors and other transcription factors. SHP regulates the transcription of a variety of target genes and controls a variety of physiological functions. For the past 10 years, great progress has been made in our understanding of the mechanism of action of SHP and the regulation of SHP gene expression. Many of the results imply that SHP has a variety of roles in the regulation of metabolic homeostasis. In this review, we discuss the current state of understanding of the structure, expression, and function of the orphan nuclear receptor, SHP.
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Affiliation(s)
- Yong-Soo Lee
- Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Korea
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Kleveland EJ, Syvertsen BL, Ruyter B, Vegusdal A, Jørgensen SM, Gjøen T. Characterization of scavenger receptor class B, type I in Atlantic salmon (Salmo salar L.). Lipids 2006; 41:1017-27. [PMID: 17263301 DOI: 10.1007/s11745-006-5052-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The scavenger receptor class B, type I (SR-BI) is an important player in regulation of mammalian lipid homeostasis. We therefore wanted to study this receptor in Atlantic salmon (Salmo salar L.), which requires a diet with particular high lipid content. We have for the first time cloned and characterized SR-BI from a salmonid fish. The predicted 494 amino acid protein contained two transmembrane domains, several putative N-glycosylation sites, and showed 72% sequence identity with the predicted homolog from zebrafish. SR-BI expression was analyzed by reverse transcription Real-Time PCR in several tissues, and a high relative expression in salmon midgut was detected, which may suggest that SR-BI has a role in uptake of lipids from the diet. We also expressed a construct of salmon myc-tagged SR-BI in salmon TO cells and HeLa cells, which gave a protein of approximately 80 kDa on reducing SDS-PAGE using an antibody against the myc-epitope. Immunofluorescence microscopy analyses of the salmon SR-BI protein in transiently transfected HeLa cells revealed staining in the cell periphery and in some intracellular membranes, but not in the nucleus, which indicated that the salmon protein may be a functional membrane protein. We also observed a high degree of co-localization using an anti-peptide SR-BI antiserum. We found that 20 microg mL(-1) insulin up-regulated the SR-BI mRNA levels in primary cultures of salmon hepatocytes relative to untreated cells. Oleic acid, EPA, DHA, or dexamethasone did not affect the relative expression of SR-BI in this liver model system. In conclusion, the salmon SR-BI cDNA encoded a protein with several features common to those of mammalian species. SR-BI gene expression was high in the intestine, which leads us to propose that SR-BI may contribute to the uptake of lipids from the diet.
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Affiliation(s)
- E J Kleveland
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
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Hu T, Chouinard M, Cox AL, Sipes P, Marcelo M, Ficorilli J, Li S, Gao H, Ryan TP, Michael MD, Michael LF. Farnesoid X receptor agonist reduces serum asymmetric dimethylarginine levels through hepatic dimethylarginine dimethylaminohydrolase-1 gene regulation. J Biol Chem 2006; 281:39831-8. [PMID: 17065154 DOI: 10.1074/jbc.m606779200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The farnesoid X receptor (FXR, NR1H4) is a bile acid-responsive nuclear receptor that plays critical roles in the transcriptional regulation genes involved in cholesterol, bile acid, triglyceride, and carbohydrate metabolism. By microarray analysis of hepatic genes from female Zucker diabetic fatty (ZDF) rats treated with the FXR agonist GW4064, we have identified dimethylarginine dimethylaminohydrolase-1 (DDAH1) as an FXR target gene. DDAH1 is a key catabolic enzyme of asymmetric dimethylarginine (ADMA), a major endogenous nitric-oxide synthase inhibitor. Sequence analysis of the DDAH1 gene reveals the presence of an FXR response element (FXRE) located 90 kb downstream of the transcription initiation site and within the first intron. Functional analysis of the putative FXRE demonstrated GW4064 dose-dependent transcriptional activation from the element, and we have demonstrated that the FXRE sequence binds the FXR-RXR heterodimer. In vivo administration of GW4064 to female ZDF rats promoted a dose-dependent and >6-fold increase in hepatic DDAH1 gene expression. The level of serum ADMA was reduced concomitantly. These findings provide a mechanism by which FXR may increase endothelium-derived nitric oxide levels through modulation of serum ADMA levels via direct regulation of hepatic DDAH1 gene expression. Thus, beneficial clinical outcomes of FXR agonist therapy may include prevention of atherosclerosis and improvement of the metabolic syndrome.
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Affiliation(s)
- Tonghuan Hu
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA
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Shibata S, Hayakawa K, Egashira Y, Sanada H. Roles of nuclear receptors in the up-regulation of hepatic cholesterol 7alpha-hydroxylase by cholestyramine in rats. Life Sci 2006; 80:546-53. [PMID: 17107691 DOI: 10.1016/j.lfs.2006.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 09/08/2006] [Accepted: 10/05/2006] [Indexed: 11/16/2022]
Abstract
Nuclear receptors are involved in regulating the expression of cholesterol 7alpha-hydroxylase (CYP7A1), however, their roles in the up-regulation of CYP7A1 by cholestyramine (CSR) are still unclear. In the present study, male Wistar rats were divided into four groups and fed [high sucrose + 10% lard diet] (H), [H + 3% CSR diet] (H + CSR), [H + 0.5% cholesterol + 0.25% sodium cholate diet] (C), or [C + 3% CSR diet] (C + CSR) for 2 weeks. Cholestyramine decreased serum and liver cholesterol levels significantly in rats fed C-based diets, but had no effect on these parameters in rats fed H-based diets. Cholestyramine raised hepatic levels of CYP7A1 mRNA and activity in both groups. The gene expression of hepatic ATP-binding cassettes A1 and G5, regulated by liver X receptor (LXR), were unchanged and down-regulated by cholestyramine, respectively. The mRNA levels of the hepatic ATP-binding cassette B11 and short heterodimer partner (SHP), regulated by farnesoid X receptor (FXR), were not changed by cholestyramine. C-based diets, which contained cholesterol and cholic acid, increased SHP mRNA levels compared to H-based diets. Consequently, in rats fed the C+CSR diet, hepatic FXR was activated by dietary bile acids, but the hepatic CYP7A1 mRNA level was increased 16-fold compared to that in rats fed an H diet. These results suggest that cholestyramine up-regulates the expression of CYP7A1 independently via LXR- or FXR-mediated pathways in rats.
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Affiliation(s)
- Shinya Shibata
- Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan.
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Natalini B, Sardella R, Camaioni E, Natalini S, Pellicciari R. Dominant Factors Affecting the Chromatographic Behaviour of Bile Acids. Chromatographia 2006. [DOI: 10.1365/s10337-006-0013-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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