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Zhang Y, Zeng M, Zhang X, Yu Q, Wang L, Zeng W, Wang Y, Suo Y, Jiang X. Tiaogan daozhuo formula attenuates atherosclerosis via activating AMPK -PPARγ-LXRα pathway. J Ethnopharmacol 2024; 324:117814. [PMID: 38286155 DOI: 10.1016/j.jep.2024.117814] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 01/19/2024] [Accepted: 01/20/2024] [Indexed: 01/31/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Tiaogan Daozhuo Formula (TGDZF) is a common formulation against atherosclerosis, however, there is limited understanding of its therapeutic mechanism. AIM OF THIS STUDY To examine the effectiveness of TGDZF in the treatment of atherosclerosis and to explore its mechanisms. MATERIALS AND METHODS In ApoE-/- mice, atherosclerosis was induced by a high-fat diet for 12 weeks and treated with TGDZF at different doses. The efficacy of TGDZF in alleviating atherosclerosis was evaluated by small animal ultrasound and histological methods. Lipid levels were measured by biochemical methods. The capacity of cholesterol efflux was tested with a cholesterol efflux assay in peritoneal macrophage, and the expression of AMPKα1, PPARγ, LXRα, and ABCA1 was examined at mRNA and protein levels. Meanwhile, RAW264.7-derived macrophages were induced into foam cells by ox-LDL, and different doses of TGDZF-conducting serum were administered. Similarly, we examined differences in intracellular lipid accumulation, cholesterol efflux rate, and AMPKα1, PPARγ, LXRα, and ABCA1 levels following drug intervention. Finally, changes in the downstream molecules were evaluated following the inhibition of AMPK by compound C or PPARγ silencing by small interfering RNA. RESULTS TGDZF administration reduced aortic plaque area and lipid accumulation in aortic plaque and hepatocytes, and improved the serum lipid profiles of ApoE-/- mice. Further study revealed that its efficacy was accompanied by an increase in cholesterol efflux rate and the expression of PPARγ, LXRα, and ABCA1 mRNA and protein, as well as the promotion of AMPKα1 phosphorylation. Moreover, similar results were caused by the intervention of TGDZF-containing serum in vitro experiments. Inhibition of AMPK and PPARγ partially blocked the regulatory effect of TGDZF, respectively. CONCLUSIONS TGDZF alleviated atherosclerosis and promoted cholesterol efflux from macrophages by activating the AMPK-PPARγ-LXRα-ABCA1 pathway.
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Affiliation(s)
- Yue Zhang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
| | - Miao Zeng
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
| | - Xiaolu Zhang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
| | - Qun Yu
- School of Preclinical Medicine, Zunyi Medical University, Guizhou, China.
| | - Luming Wang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
| | - Wenyun Zeng
- Traditional Chinese Medicine Department, Ganzhou People's Hospital, Ganzhou, China.
| | - Yijing Wang
- School of Nursing, Tianjin University of Chinese Medicine, Tianjin, China.
| | - Yanrong Suo
- Traditional Chinese Medicine Department, Ganzhou People's Hospital, Ganzhou, China.
| | - Xijuan Jiang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
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Santa-María C, López-Enríquez S, Montserrat-de la Paz S, Geniz I, Reyes-Quiroz ME, Moreno M, Palomares F, Sobrino F, Alba G. Update on Anti-Inflammatory Molecular Mechanisms Induced by Oleic Acid. Nutrients 2023; 15:nu15010224. [PMID: 36615882 PMCID: PMC9824542 DOI: 10.3390/nu15010224] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023] Open
Abstract
In 2010, the Mediterranean diet was recognized by UNESCO as an Intangible Cultural Heritage of Humanity. Olive oil is the most characteristic food of this diet due to its high nutraceutical value. The positive effects of olive oil have often been attributed to its minor components; however, its oleic acid (OA) content (70-80%) is responsible for its many health properties. OA is an effective biomolecule, although the mechanism by which OA mediates beneficial physiological effects is not fully understood. OA influences cell membrane fluidity, receptors, intracellular signaling pathways, and gene expression. OA may directly regulate both the synthesis and activities of antioxidant enzymes. The anti-inflammatory effect may be related to the inhibition of proinflammatory cytokines and the activation of anti-inflammatory ones. The best-characterized mechanism highlights OA as a natural activator of sirtuin 1 (SIRT1). Oleoylethanolamide (OEA), derived from OA, is an endogenous ligand of the peroxisome proliferator-activated receptor alpha (PPARα) nuclear receptor. OEA regulates dietary fat intake and energy homeostasis and has therefore been suggested to be a potential therapeutic agent for the treatment of obesity. OEA has anti-inflammatory and antioxidant effects. The beneficial effects of olive oil may be related to the actions of OEA. New evidence suggests that oleic acid may influence epigenetic mechanisms, opening a new avenue in the exploration of therapies based on these mechanisms. OA can exert beneficial anti-inflammatory effects by regulating microRNA expression. In this review, we examine the cellular reactions and intracellular processes triggered by OA in T cells, macrophages, and neutrophils in order to better understand the immune modulation exerted by OA.
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Affiliation(s)
- Consuelo Santa-María
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Seville, 41012 Seville, Spain
- Correspondence: (C.S.-M.); (S.L.-E.)
| | - Soledad López-Enríquez
- Departamento de Bioquímica Médica, Biología Molecular e Inmunología, Facultad de Medicina, Universidad de Seville, 41009 Seville, Spain
- Correspondence: (C.S.-M.); (S.L.-E.)
| | - Sergio Montserrat-de la Paz
- Departamento de Bioquímica Médica, Biología Molecular e Inmunología, Facultad de Medicina, Universidad de Seville, 41009 Seville, Spain
| | - Isabel Geniz
- Distrito Sanitario Seville Norte y Aljarafe, Servicio Andaluz de Salud, 41008 Seville, Spain
| | - María Edith Reyes-Quiroz
- Departamento de Bioquímica Médica, Biología Molecular e Inmunología, Facultad de Medicina, Universidad de Seville, 41009 Seville, Spain
| | - Manuela Moreno
- Departamento de Farmacia y Nutrición, Hospital Costa del Sol, 29603 Málaga, Spain
| | - Francisca Palomares
- Departamento de Bioquímica Médica, Biología Molecular e Inmunología, Facultad de Medicina, Universidad de Seville, 41009 Seville, Spain
| | - Francisco Sobrino
- Departamento de Bioquímica Médica, Biología Molecular e Inmunología, Facultad de Medicina, Universidad de Seville, 41009 Seville, Spain
| | - Gonzalo Alba
- Departamento de Bioquímica Médica, Biología Molecular e Inmunología, Facultad de Medicina, Universidad de Seville, 41009 Seville, Spain
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3
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Moldavski O, Zushin PJH, Berdan CA, Van Eijkeren RJ, Jiang X, Qian M, Ory DS, Covey DF, Nomura DK, Stahl A, Weiss EJ, Zoncu R. 4β-Hydroxycholesterol is a prolipogenic factor that promotes SREBP1c expression and activity through the liver X receptor. J Lipid Res 2021; 62:100051. [PMID: 33631213 PMCID: PMC8042401 DOI: 10.1016/j.jlr.2021.100051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/06/2021] [Accepted: 02/12/2021] [Indexed: 12/16/2022] Open
Abstract
Oxysterols are oxidized derivatives of cholesterol that play regulatory roles in lipid biosynthesis and homeostasis. How oxysterol signaling coordinates different lipid classes such as sterols and triglycerides remains incompletely understood. Here, we show that 4β-hydroxycholesterol (HC) (4β-HC), a liver and serum abundant oxysterol of poorly defined functions, is a potent and selective inducer of the master lipogenic transcription factor, SREBP1c, but not the related steroidogenic transcription factor SREBP2. By correlating tracing of lipid synthesis with lipogenic gene expression profiling, we found that 4β-HC acts as a putative agonist for the liver X receptor (LXR), a sterol sensor and transcriptional regulator previously linked to SREBP1c activation. Unique among the oxysterol agonists of the LXR, 4β-HC induced expression of the lipogenic program downstream of SREBP1c and triggered de novo lipogenesis both in primary hepatocytes and in the mouse liver. In addition, 4β-HC acted in parallel to insulin-PI3K–dependent signaling to stimulate triglyceride synthesis and lipid-droplet accumulation. Thus, 4β-HC is an endogenous regulator of de novo lipogenesis through the LXR-SREBP1c axis.
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Affiliation(s)
- Ofer Moldavski
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA; The Paul F. Glenn Center for Aging Research, University of California, Berkeley, Berkeley, CA, USA; Cardiovascular Research Institute, UCSF, San Francisco, CA, USA
| | - Peter-James H Zushin
- Department of Nutritional Sciences and Toxicology, University of California at Berkeley, Berkeley, CA, USA
| | - Charles A Berdan
- Department of Nutritional Sciences and Toxicology, University of California at Berkeley, Berkeley, CA, USA
| | - Robert J Van Eijkeren
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA; The Paul F. Glenn Center for Aging Research, University of California, Berkeley, Berkeley, CA, USA
| | - Xuntian Jiang
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St Louis, MO, USA
| | - Mingxing Qian
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO, USA
| | - Daniel S Ory
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St Louis, MO, USA
| | - Douglas F Covey
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO, USA
| | - Daniel K Nomura
- Department of Nutritional Sciences and Toxicology, University of California at Berkeley, Berkeley, CA, USA
| | - Andreas Stahl
- Department of Nutritional Sciences and Toxicology, University of California at Berkeley, Berkeley, CA, USA
| | - Ethan J Weiss
- Cardiovascular Research Institute, UCSF, San Francisco, CA, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA; The Paul F. Glenn Center for Aging Research, University of California, Berkeley, Berkeley, CA, USA.
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Zhao L, Lei W, Deng C, Wu Z, Sun M, Jin Z, Song Y, Yang Z, Jiang S, Shen M, Yang Y. The roles of liver X receptor α in inflammation and inflammation-associated diseases. J Cell Physiol 2020; 236:4807-4828. [PMID: 33305467 DOI: 10.1002/jcp.30204] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [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: 06/20/2020] [Revised: 10/19/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022]
Abstract
Liver X receptor α (LXRα; also known as NR1H3), an isoform of LXRs, is a member of the nuclear receptor family of transcription factors and plays essential roles in the transcriptional control of cholesterol homeostasis. Previous in-depth phenotypic analyses of mouse models with deficient LXRα have also demonstrated various physiological functions of this receptor within inflammatory responses. LXRα activation exerts a combination of metabolic and anti-inflammatory actions resulting in the modulation and the amelioration of inflammatory disorders. The tight "repercussions" between LXRα and inflammation, as well as cholesterol homeostasis, have suggested that LXRα could be pharmacologically targeted in pathologies such as atherosclerosis, acute lung injury, and Alzheimer's disease. This review gives an overview of the recent advances in understanding the roles of LXRα in inflammation and inflammation-associated diseases, which will help in the design of future experimental researches on the potential of LXRα and advance the investigation of LXRα as pharmacological inflammatory targets.
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Affiliation(s)
- Lin Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education Life of Sciences, Northwest University, Xi'an, China.,Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Wangrui Lei
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education Life of Sciences, Northwest University, Xi'an, China
| | - Chao Deng
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Zhen Wu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education Life of Sciences, Northwest University, Xi'an, China
| | - Meng Sun
- Department of Cardiology, The First Hospital of Shanxi Medical University, Taiyuan, China
| | - Zhenxiao Jin
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Yanbin Song
- Department of Cardiology, Affiliated Hospital, Yan'an University, China
| | - Zhi Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education Life of Sciences, Northwest University, Xi'an, China
| | - Shuai Jiang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education Life of Sciences, Northwest University, Xi'an, China
| | - Mingzhi Shen
- Hainan Hospital of PLA General Hospital, The Second School of Clinical Medicine, Southern Medical University, Sanya, Hainan, China.,Hainan Branch of National Clinical Reasearch Center of Geriatrics Disease, Sanya, Hainan, China
| | - Yang Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education Life of Sciences, Northwest University, Xi'an, China
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5
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Hashimoto S, Takanari H, Compe E, Egly JM. Dysregulation of LXR responsive genes contribute to ichthyosis in trichothiodystrophy. J Dermatol Sci 2020; 97:201-207. [PMID: 32037099 DOI: 10.1016/j.jdermsci.2020.01.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 10/15/2019] [Revised: 12/29/2019] [Accepted: 01/21/2020] [Indexed: 02/01/2023]
Abstract
BACKGROUND Trichothiodystrophy (TTD) is a rare autosomal recessive disorder characterised by brittle hairs and various systemic symptoms, including photosensitivity and ichthyosis. While photosensitivity could result from DNA repair defects, other TTD clinical features might be due to deficiencies in certain molecular processes. OBJECTIVES The aim of this study was to understand the pathophysiological mechanism of ichthyosis in TTD, focused on the transcriptional dysregulation. METHODS TTD mouse skin tissue and keratinocytes were pathologically and physiologically examined to identify the alteration of lipid homeostasis in TTD with ichtyosis. Gene expression of certain lipid transporter was assessed in fibroblasts derived from TTD patients and TTD mouse keratinocytes. RESULTS Histopathology and electron microscopy revealed abnormal lipid composition in TTD mice skin. In addition to abnormal cholesterol dynamics, TTD mouse keratinocytes exhibit impaired expression of Liver X receptor (LXR) responsive genes, including Abca12, a key regulator of Harlequin ichthyosis, and Abcg1 that is involved in the cholesterol transport process in the epidermis. Strikingly, dysregulation of LXR responsive genes has been only observed in cells isolated from TTD patients who developed ichthyosis. CONCLUSIONS Our results suggest that the altered expression of the LXR-responsive genes contribute to the pathophysiology of ichthyosis in TTD. These findings provide a new drug discovery target for TTD.
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Affiliation(s)
- Satoru Hashimoto
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université de Strasbourg, Strasbourg, France; Clinical Research Center for Diabetes, Tokushima University Hospital, Tokushima, Japan; Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
| | - Hiroki Takanari
- Clinical Research Center for Diabetes, Tokushima University Hospital, Tokushima, Japan; Department of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics, Tokushima, Japan
| | - Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université de Strasbourg, Strasbourg, France
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université de Strasbourg, Strasbourg, France.
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Abstract
Cholesterol is essential for maintaining membrane fluidity in eukaryotes. Additionally, the synthetic cascade of cholesterol results in precursor molecules important for cellular function such as lipid raft formation and protein prenylation. As such, cholesterol homeostasis is tightly regulated. Interestingly, it is now known that some cholesterol precursors and many metabolites serve as active signaling molecules, binding to different classes of receptors including the nuclear receptors. Furthermore, many cholesterol metabolites or their nuclear receptors have been implicated in the regulation of the immune system in normal physiology and disease. Therefore, in this focused review, cholesterol homeostasis and nuclear receptors involved in this regulation will be discussed, with particular emphasis on how these cascades influence the immune system.
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Affiliation(s)
- Sayyed Hamed Shahoei
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana Champaign, Urbana, IL, United States
| | - Erik R Nelson
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana Champaign, Urbana, IL, United States; Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, United States; University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, IL, United States; Carl R. Woese Institute for Genomic Biology, Anticancer Discovery from Pets to People Theme, University of Illinois at Urbana Champaign, Urbana, IL, United States.
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7
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Ramón-Vázquez A, de la Rosa JV, Tabraue C, Lopez F, Díaz-Chico BN, Bosca L, Tontonoz P, Alemany S, Castrillo A. Common and Differential Transcriptional Actions of Nuclear Receptors Liver X Receptors α and β in Macrophages. Mol Cell Biol 2019; 39:e00376-18. [PMID: 30602495 PMCID: PMC6379585 DOI: 10.1128/mcb.00376-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/29/2018] [Accepted: 12/07/2018] [Indexed: 02/07/2023] Open
Abstract
The liver X receptors α and β (LXRα and LXRβ) are oxysterol-activated transcription factors that coordinately regulate gene expression that is important for cholesterol and fatty acid metabolism. In addition to their roles in lipid metabolism, LXRs participate in the transcriptional regulation of macrophage activation and are considered potent regulators of inflammation. LXRs are highly similar, and despite notable exceptions, most of their reported functions are substantially overlapping. However, their individual genomic distribution and transcriptional capacities have not been characterized. Here, we report a macrophage cellular model expressing equivalent levels of tagged LXRs. Analysis of data from chromatin immunoprecipitation coupled with deep sequencing revealed that LXRα and LXRβ occupy both overlapping and exclusive genomic regulatory sites of target genes and also control the transcription of a receptor-exclusive set of genes. Analysis of genomic H3K27 acetylation and mRNA transcriptional changes in response to synthetic agonist or antagonist treatments revealed a putative mode of pharmacologically independent regulation of transcription. Integration of microarray and sequencing data enabled the description of three possible mechanisms of LXR transcriptional activation. Together, these results contribute to our understanding of the common and differential genomic actions of LXRs and their impact on biological processes in macrophages.
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Affiliation(s)
- Ana Ramón-Vázquez
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, Madrid, Spain
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Juan Vladimir de la Rosa
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, Madrid, Spain
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Carlos Tabraue
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Felix Lopez
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Bonifacio Nicolas Díaz-Chico
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Lisardo Bosca
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, Madrid, Spain
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Susana Alemany
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, Madrid, Spain
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Antonio Castrillo
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, Madrid, Spain
- Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Grupo de Investigación Medio Ambiente y Salud, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
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8
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Wang W, Zhang ZZ, Wu Y, Wang RQ, Chen JW, Chen J, Zhang Y, Chen YJ, Geng M, Xu ZD, Dai M, Li JH, Pan LL. (-)-Epigallocatechin-3-Gallate Ameliorates Atherosclerosis and Modulates Hepatic Lipid Metabolic Gene Expression in Apolipoprotein E Knockout Mice: Involvement of TTC39B. Front Pharmacol 2018; 9:195. [PMID: 29593532 PMCID: PMC5854642 DOI: 10.3389/fphar.2018.00195] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/21/2018] [Indexed: 12/22/2022] Open
Abstract
Background: Aberrant chronic inflammation and excess accumulation of lipids play a pivotal role in the occurrence and progression of atherosclerosis. (–)-Epigallocatechin-3-gallate (EGCG), the major catechins in green tea, displayed anti-atherosclerotic properties in vivo and in vitro. However, the effects and underlying mechanism of EGCG on atherosclerosis remain unclear. Methods: Male apolipoprotein E-knockout (ApoE-/-) mice (7 weeks old) fed with high-fat diet (HFD) were treated with normal saline or EGCG (40 mg/kg/d, i.g.) for 18 weeks. Atherosclerotic plaque and liver lipid accumulation were measured by Oil Red staining. Plasma lipids and cytokines were detected using commercial kits. The expression of protein and mRNA was analyzed by western blot and quantitative real-time reverse transcription-polymerase chain reaction, respectively. Results: EGCG administration markedly attenuated atherosclerotic plaque formation in HFD-fed ApoE-/- mice, which were accompanied by increased plasma interleukin-10 (IL-10) level and decreased plasma IL-6 and tumor necrosis factor-α (TNF-α) levels. In addition, EGCG modulated high-fat-induced dyslipidemia, evidencing by decreased total cholesterol (TC) and low-density lipoprotein levels and increased high-density lipoprotein level. Meanwhile, EGCG treatment alleviated high-fat-mediated liver lipid accumulation and decreased liver TC and triglyceride. Mechanistically, EGCG significantly modulated high-fat-induced hepatic tetratricopeptide repeat domain protein 39B (TTC39B) expression and its related genes (Lxrβ, Abcg5, Abcg8, Abca1, Srebf1, Scd1, Scd2, Fas, Elovl5, Mylip) expression in liver from ApoE-/- mice. Notably, EGCG remarkably induced hepatic liver X receptor α (LXRα) and LXRβ expression and inhibited both precursor and mature sterol regulatory element binding transcription factor-1 (SREBP-1) expression. Conclusion: Taken together, our data for the first time suggested that TTC39B was involved in EGCG-mediated anti-atherosclerotic effects through modulation of LXR/SREBP-1 pathway.
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Affiliation(s)
- Wei Wang
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Zheng-Zhu Zhang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, China
| | - Yan Wu
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Ru-Qing Wang
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Jin-Wu Chen
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Jing Chen
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Yan Zhang
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Ya-Jun Chen
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Ming Geng
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Zhong-Dong Xu
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Min Dai
- Anhui Key Laboratory for Research and Development of Traditional Chinese Medicine, Key Laboratory of Xin'an Medicine, Ministry of Education, School of Pharmacy, Anhui University of Chinese Medicine, Hefei, China
| | - Jin-Hua Li
- School of Life Sciences, Hefei Normal University, Hefei, China
| | - Li-Long Pan
- School of Medicine, Jiangnan University, Wuxi, China
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9
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Zhang L, Rajbhandari P, Priest C, Sandhu J, Wu X, Temel R, Castrillo A, de Aguiar Vallim TQ, Sallam T, Tontonoz P. Inhibition of cholesterol biosynthesis through RNF145-dependent ubiquitination of SCAP. eLife 2017; 6:e28766. [PMID: 29068315 PMCID: PMC5656429 DOI: 10.7554/elife.28766] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 10/05/2017] [Indexed: 12/25/2022] Open
Abstract
Cholesterol homeostasis is maintained through concerted action of the SREBPs and LXRs. Here, we report that RNF145, a previously uncharacterized ER membrane ubiquitin ligase, participates in crosstalk between these critical signaling pathways. RNF145 expression is induced in response to LXR activation and high-cholesterol diet feeding. Transduction of RNF145 into mouse liver inhibits the expression of genes involved in cholesterol biosynthesis and reduces plasma cholesterol levels. Conversely, acute suppression of RNF145 via shRNA-mediated knockdown, or chronic inactivation of RNF145 by genetic deletion, potentiates the expression of cholesterol biosynthetic genes and increases cholesterol levels both in liver and plasma. Mechanistic studies show that RNF145 triggers ubiquitination of SCAP on lysine residues within a cytoplasmic loop essential for COPII binding, potentially inhibiting its transport to Golgi and subsequent processing of SREBP-2. These findings define an additional mechanism linking hepatic sterol levels to the reciprocal actions of the SREBP-2 and LXR pathways.
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Affiliation(s)
- Li Zhang
- Department of Pathology and Laboratory MedicineHoward Hughes Medical Institute, University of California, Los AngelesLos AngelesUnited States
| | - Prashant Rajbhandari
- Department of Pathology and Laboratory MedicineHoward Hughes Medical Institute, University of California, Los AngelesLos AngelesUnited States
| | - Christina Priest
- Department of Pathology and Laboratory MedicineHoward Hughes Medical Institute, University of California, Los AngelesLos AngelesUnited States
| | - Jaspreet Sandhu
- Department of Pathology and Laboratory MedicineHoward Hughes Medical Institute, University of California, Los AngelesLos AngelesUnited States
| | - Xiaohui Wu
- Department of Medicine, Division of CardiologyUniversity of California, Los AngelesLos AngelesUnited States
| | - Ryan Temel
- Saha Cardiovascular Research CenterUniversity of KentuckyLexingtonUnited States
- Department of Pharmacology and Nutritional SciencesUniversity of KentuckyLexingtonUnited States
| | - Antonio Castrillo
- Instituto de Investigaciones Biomédicas Alberto SolsCSIC-Universidad Autónoma de Madrid, Unidad de Biomedicina-Universidad de Las Palmas de Gran Canaria (Unidad asociada al CSIC)Las Palmas de Gran CanariaSpain
- Instituto Universitario de Investigaciones Biomédicas y SanitariasUniversidad de Las Palmas de Gran CanariaLas Palmas de Gran CanariaSpain
| | - Thomas Q de Aguiar Vallim
- Department of Medicine, Division of CardiologyUniversity of California, Los AngelesLos AngelesUnited States
| | - Tamer Sallam
- Department of Medicine, Division of CardiologyUniversity of California, Los AngelesLos AngelesUnited States
| | - Peter Tontonoz
- Department of Pathology and Laboratory MedicineHoward Hughes Medical Institute, University of California, Los AngelesLos AngelesUnited States
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10
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Ito A, Hong C, Oka K, Salazar JV, Diehl C, Witztum JL, Diaz M, Castrillo A, Bensinger SJ, Chan L, Tontonoz P. Cholesterol Accumulation in CD11c + Immune Cells Is a Causal and Targetable Factor in Autoimmune Disease. Immunity 2016; 45:1311-26. [PMID: 28002731 DOI: 10.1016/j.immuni.2016.11.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 07/25/2016] [Accepted: 10/20/2016] [Indexed: 02/06/2023]
Abstract
Liver X receptors (LXRs) are regulators of cholesterol metabolism that also modulate immune responses. Inactivation of LXR α and β in mice leads to autoimmunity; however, how the regulation of cholesterol metabolism contributes to autoimmunity is unclear. Here we found that cholesterol loading of CD11c+ cells triggered the development of autoimmunity, whereas preventing excess lipid accumulation by promoting cholesterol efflux was therapeutic. LXRβ-deficient mice crossed to the hyperlipidemic ApoE-deficient background or challenged with a high-cholesterol diet developed autoantibodies. Cholesterol accumulation in lymphoid organs promoted T cell priming and stimulated the production of the B cell growth factors Baff and April. Conversely, B cell expansion and the development of autoantibodies in ApoE/LXR-β-deficient mice was reversed by ApoA-I expression. These findings implicate cholesterol imbalance as a contributor to immune dysfunction and suggest that stimulating HDL-dependent reverse cholesterol transport could be beneficial in the setting of autoimmune disease.
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11
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Abstract
The Liver X Receptors (LXRs) are oxysterol-activated transcription factors that upregulate a suite of genes that together promote coordinated mobilization of excess cholesterol from cells and from the body. The LXRs, like other nuclear receptors, are anti-inflammatory, inhibiting signal-dependent induction of pro-inflammatory genes by nuclear factor-κB, activating protein-1, and other transcription factors. Synthetic LXR agonists have been shown to ameliorate atherosclerosis and a wide range of inflammatory disorders in preclinical animal models. Although this has suggested potential for application to human disease, systemic LXR activation is complicated by hepatic steatosis and hypertriglyceridemia, consequences of lipogenic gene induction in the liver by LXRα. The past several years have seen the development of multiple advanced LXR therapeutics aiming to avoid hepatic lipogenesis, including LXRβ-selective agonists, tissue-selective agonists, and transrepression-selective agonists. Although several synthetic LXR agonists have made it to phase I clinical trials, none have progressed due to unforeseen adverse reactions or undisclosed reasons. Nonetheless, several sophisticated pharmacologic strategies, including structure-guided drug design, cell-specific drug targeting, as well as non-systemic drug routes have been initiated and remain to be comprehensively explored. In addition, recent studies have identified potential utility for targeting the LXRs during therapy with other agents, such as glucocorticoids and rexinoids. Despite the pitfalls encountered to date in translation of LXR agonists to human disease, it appears likely that this accelerating field will ultimately yield effective and safe applications for LXR targeting in humans.
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Affiliation(s)
- Michael B Fessler
- National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, P.O. Box 12233, MD D2-01, Research Triangle Park, NC 27709, United States.
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12
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Cheng TJ, Lin SW, Chen CW, Guo HR, Wang YJ. Arsenic trioxide suppresses liver X receptor β and enhances cholesteryl ester transfer protein expression without affecting the liver X receptor α in HepG2 cells. Chem Biol Interact 2016; 258:288-96. [PMID: 27622732 DOI: 10.1016/j.cbi.2016.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 03/29/2016] [Revised: 08/21/2016] [Accepted: 09/09/2016] [Indexed: 12/12/2022]
Abstract
Chronic arsenic exposure is associated with cerebrovascular disease and the formation of atherosclerotic lesions. Our previous study demonstrated that arsenic trioxide (ATO) exposure was associated with atherosclerotic lesion formation through alterations in lipid metabolism in the reverse cholesterol transport process. In mouse livers, the expression of the liver X receptor β (LXR-β) and the cholesteryl ester transfer protein (CETP) was suppressed without any changes to the lipid profile. The aim of this study was to elucidate whether ATO contributes to atherosclerotic lesions by suppressing LXR-β and CETP levels in hepatocytes. HepG2 cells, human hepatocytes, were exposed to different ATO concentrations in vitro. Cell viability was determined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay. The liver X receptor α (LXR-α), LXR-β, sterol regulatory element-binding protein-1c (SREBP-1c) and CETP protein levels were measured by Western blotting, and their mRNA levels were measured by real-time PCR. Cholesterol efflux was analyzed by flow cytometry. The results showed ATO inhibited LXR-β mRNA and protein levels with a subsequent decrease in SREBP-1c protein levels and reduced cholesterol efflux from HepG2 cells into the extracellular space without influencing LXR-α mRNA and protein levels. CETP protein levels of HepG2 cells were significantly elevated under arsenic exposure. Transfection of LXR-β shRNA did not change CETP protein levels, implying that there is no cross-talk between LXR-β and CETP. In conclusion, arsenic not only inhibits LXR-β and SREBP-1c mRNA and protein levels but also independently increases CETP protein levels in HepG2 cells.
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Affiliation(s)
- Tain-Junn Cheng
- Department of Neurology and Occupational Medicine, Chi Mei Medical Center, 901 Zhonghua Road, Yongkang Dist., Tainan 710, Taiwan; Department of Occupational Safety and Health/Institute of Industrial Safety and Disaster Prevention, College of Sustainable Environment, Chia Nan University of Pharmacy and Science, 60 Sec. 1, Erren Road, Rende Dist., Tainan 71710, Taiwan
| | - Shu-Wen Lin
- Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan
| | - Chih-Wei Chen
- Department of Occupational Safety and Health/Institute of Industrial Safety and Disaster Prevention, College of Sustainable Environment, Chia Nan University of Pharmacy and Science, 60 Sec. 1, Erren Road, Rende Dist., Tainan 71710, Taiwan; Division of Neurosurgery, Department of Surgery, Chi Mei Medical Center, 901 Zhonghua Road, Yongkang Dist., Tainan 710, Taiwan
| | - How-Ran Guo
- Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan; Department of Occupational and Environmental Medicine, National Cheng Kung University Hospital, 138 Sheng-Li Road, Tainan 704, Taiwan.
| | - Ying-Jang Wang
- Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan; Department of Biomedical and Informatics, Asia University, 500 Lioufeng Road, Wufeng, Taichung, 41354, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, 500 Lioufeng Road, Wufeng, Taichung, 41354, Taiwan.
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13
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Sallam T, Jones MC, Gilliland T, Zhang L, Wu X, Eskin A, Sandhu J, Casero D, Vallim TQ, Hong C, Katz M, Lee R, Whitelegge J, Tontonoz P. Feedback modulation of cholesterol metabolism by the lipid-responsive non-coding RNA LeXis. Nature 2016; 534:124-8. [PMID: 27251289 DOI: 10.1038/nature17674] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 03/18/2016] [Indexed: 01/21/2023]
Abstract
Liver X receptors (LXRs) are transcriptional regulators of cellular and systemic cholesterol homeostasis. Under conditions of excess cholesterol, LXR activation induces the expression of several genes involved in cholesterol efflux, facilitates cholesterol esterification by promoting fatty acid synthesis, and inhibits cholesterol uptake by the low-density lipoprotein receptor. The fact that sterol content is maintained in a narrow range in most cell types and in the organism as a whole suggests that extensive crosstalk between regulatory pathways must exist. However, the molecular mechanisms that integrate LXRs with other lipid metabolic pathways are incompletely understood. Here we show that ligand activation of LXRs in mouse liver not only promotes cholesterol efflux, but also simultaneously inhibits cholesterol biosynthesis. We further identify the long non-coding RNA LeXis as a mediator of this effect. Hepatic LeXis expression is robustly induced in response to a Western diet (high in fat and cholesterol) or to pharmacological LXR activation. Raising or lowering LeXis levels in the liver affects the expression of genes involved in cholesterol biosynthesis and alters the cholesterol levels in the liver and plasma. LeXis interacts with and affects the DNA interactions of RALY, a heterogeneous ribonucleoprotein that acts as a transcriptional cofactor for cholesterol biosynthetic genes in the mouse liver. These findings outline a regulatory role for a non-coding RNA in lipid metabolism and advance our understanding of the mechanisms that coordinate sterol homeostasis.
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Tian XY, Ganeshan K, Hong C, Nguyen KD, Qiu Y, Kim J, Tangirala RK, Tontonoz P, Chawla A, Chawla A. Thermoneutral Housing Accelerates Metabolic Inflammation to Potentiate Atherosclerosis but Not Insulin Resistance. Cell Metab 2016; 23:165-78. [PMID: 26549485 PMCID: PMC4715491 DOI: 10.1016/j.cmet.2015.10.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 09/19/2015] [Accepted: 10/09/2015] [Indexed: 12/27/2022]
Abstract
Chronic, low-grade inflammation triggered by excess intake of dietary lipids has been proposed to contribute to the pathogenesis of metabolic disorders, such as obesity, insulin resistance, type 2 diabetes, and atherosclerosis. Although considerable evidence supports a causal association between inflammation and metabolic diseases, most tests of this link have been performed in cold-stressed mice that are housed below their thermoneutral zone. We report here that thermoneutral housing of mice has a profound effect on the development of metabolic inflammation, insulin resistance, and atherosclerosis. Mice housed at thermoneutrality develop metabolic inflammation in adipose tissue and in the vasculature at an accelerated rate. Unexpectedly, this increased inflammatory response contributes to the progression of atherosclerosis but not insulin resistance. These findings not only suggest that metabolic inflammation can be uncoupled from obesity-associated insulin resistance, but also point to how thermal stress might limit our ability to faithfully model human diseases in mice.
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Affiliation(s)
- Xiao Yu Tian
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94143, USA
| | - Kirthana Ganeshan
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94143, USA
| | - Cynthia Hong
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Khoa D Nguyen
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94143, USA
| | - Yifu Qiu
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94143, USA
| | - Jason Kim
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Rajendra K Tangirala
- Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | | | - Ajay Chawla
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94143, USA; Departments of Physiology and Medicine, University of California San Francisco, San Francisco, CA 94143, USA.
| | - Ajay Chawla
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA 94143, USA; Departments of Physiology and Medicine, University of California San Francisco, San Francisco, CA 94143, USA.
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15
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Korytowski W, Wawak K, Pabisz P, Schmitt JC, Chadwick AC, Sahoo D, Girotti AW. Impairment of Macrophage Cholesterol Efflux by Cholesterol Hydroperoxide Trafficking: Implications for Atherogenesis Under Oxidative Stress. Arterioscler Thromb Vasc Biol 2015; 35:2104-13. [PMID: 26315403 DOI: 10.1161/atvbaha.115.306210] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/05/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Oxidative stress associated with cardiovascular disease can produce various oxidized lipids, including cholesterol oxides, such as 7-hydroperoxide (7-OOH), 7-hydroxide (7-OH), and 7-ketone (7=O). Unlike 7=O and 7-OH, 7-OOH is redox active, giving rise to the others via potentially toxic-free radical reactions. We tested the novel hypothesis that under oxidative stress conditions, steroidogenic acute regulatory (StAR) family proteins not only deliver cholesterol to/into mitochondria of vascular macrophages, but also 7-OOH, which induces peroxidative damage that impairs early stage reverse cholesterol transport. APPROACH AND RESULTS Stimulation of human monocyte-derived THP-1 macrophages with dibutyryl-cAMP resulted in substantial upregulation of StarD1 and ATP-binding cassette (ABC) transporter, ABCA1. Small interfering RNA-induced StarD1 knockdown before stimulation had no effect on StarD4, but reduced ABCA1 upregulation, linking the latter to StarD1 functionality. Mitochondria in stimulated StarD1-knockdown cells internalized 7-OOH slower than nonstimulated controls and underwent less 7-OOH-induced lipid peroxidation and membrane depolarization, as probed with C11-BODIPY (4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-inda-cene-3-undecanoic acid) and JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-benzimidazolylcarbocyanine iodide), respectively. Major functional consequences of 7-OOH exposure were (1) loss of mitochondrial CYP27A1 activity, (2) reduced 27-hydroxycholesterol (27-OH) output, and (3) downregulation of cholesterol-exporting ABCA1 and ABCG1. Consistently, 7-OOH-challenged macrophages exported less cholesterol to apoA-I or high-density lipoprotein than did nonchallenged controls. StarD1-mediated 7-OOH transport was also found to be highly cytotoxic, whereas 7=O and 7-OH were minimally toxic. CONCLUSIONS This study describes a previously unrecognized mechanism by which macrophage cholesterol efflux can be incapacitated under oxidative stress-linked disorders, such as chronic obesity and hypertension. Our findings provide new insights into the role of macrophage redox damage/dysfunction in atherogenesis.
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Affiliation(s)
- Witold Korytowski
- From the Department of Biochemistry (A.W.G., W.K., D.S., A.C.C., J.C.S.) and Department of Medicine (D.S.), Medical College of Wisconsin, Milwaukee; and Department of Biophysics, Jagiellonian University, Krakow, Poland (W.K., K.W., P.P.).
| | - Katarzyna Wawak
- From the Department of Biochemistry (A.W.G., W.K., D.S., A.C.C., J.C.S.) and Department of Medicine (D.S.), Medical College of Wisconsin, Milwaukee; and Department of Biophysics, Jagiellonian University, Krakow, Poland (W.K., K.W., P.P.)
| | - Pawel Pabisz
- From the Department of Biochemistry (A.W.G., W.K., D.S., A.C.C., J.C.S.) and Department of Medicine (D.S.), Medical College of Wisconsin, Milwaukee; and Department of Biophysics, Jagiellonian University, Krakow, Poland (W.K., K.W., P.P.)
| | - Jared C Schmitt
- From the Department of Biochemistry (A.W.G., W.K., D.S., A.C.C., J.C.S.) and Department of Medicine (D.S.), Medical College of Wisconsin, Milwaukee; and Department of Biophysics, Jagiellonian University, Krakow, Poland (W.K., K.W., P.P.)
| | - Alexandra C Chadwick
- From the Department of Biochemistry (A.W.G., W.K., D.S., A.C.C., J.C.S.) and Department of Medicine (D.S.), Medical College of Wisconsin, Milwaukee; and Department of Biophysics, Jagiellonian University, Krakow, Poland (W.K., K.W., P.P.)
| | - Daisy Sahoo
- From the Department of Biochemistry (A.W.G., W.K., D.S., A.C.C., J.C.S.) and Department of Medicine (D.S.), Medical College of Wisconsin, Milwaukee; and Department of Biophysics, Jagiellonian University, Krakow, Poland (W.K., K.W., P.P.)
| | - Albert W Girotti
- From the Department of Biochemistry (A.W.G., W.K., D.S., A.C.C., J.C.S.) and Department of Medicine (D.S.), Medical College of Wisconsin, Milwaukee; and Department of Biophysics, Jagiellonian University, Krakow, Poland (W.K., K.W., P.P.).
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16
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Mansuy-Aubert V, Gautron L, Lee S, Bookout AL, Kusminski C, Sun K, Zhang Y, Scherer PE, Mangelsdorf DJ, Elmquist JK. Loss of the liver X receptor LXRα/β in peripheral sensory neurons modifies energy expenditure. eLife 2015; 4. [PMID: 26076474 PMCID: PMC4467361 DOI: 10.7554/elife.06667] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 05/14/2015] [Indexed: 11/13/2022] Open
Abstract
Peripheral neural sensory mechanisms play a crucial role in metabolic regulation but less is known about the mechanisms underlying vagal sensing itself. Recently, we identified an enrichment of liver X receptor alpha and beta (LXRα/β) in the nodose ganglia of the vagus nerve. In this study, we show mice lacking LXRα/β in peripheral sensory neurons have increased energy expenditure and weight loss when fed a Western diet (WD). Our findings suggest that the ability to metabolize and sense cholesterol and/or fatty acids in peripheral neurons is an important requirement for physiological adaptations to WDs. DOI:http://dx.doi.org/10.7554/eLife.06667.001 The vagus nerves run from the brainstem to the heart and the digestive system and help to control several processes including digestion and heart rate. Because of their role in regulating food intake, these nerves are attractive targets for scientists hoping to develop treatments for obesity. There are two types of fat tissue found in mammals: white fat, which is used as an energy store and makes up most of the extra fat seen in obese individuals; and brown fat, which can generate body heat. The vagus nerves monitor fat and cholesterol levels in the body via receptor proteins that respond to messages sent from the fat tissues and the liver. Previous research unexpectedly found that mice genetically engineered to lack these receptor proteins—called LXRα and LXRβ—do not become obese even when fed a high-fat, high-cholesterol diet that would make normal mice gain excessive weight. Mansuy-Aubert et al. have now investigated in more detail why mice without these receptor proteins are resistant to obesity. When fed a high-fat, high-cholesterol diet, mice that lacked the LXRα and LXRβ receptors in sensory neurons had higher cholesterol levels in their nerve cells than normal mice on the same diet. Mice lacking these receptors also burned more energy and gained less weight than normal mice. Next, Mansuy-Aubert et al. examined fat tissue from both types of mice. This revealed that the heat-generating brown fat was more active in mice lacking the LXRα and LXRβ receptors. Some of the white fat in these mice had also become more like brown fat, allowing the mice to burn more energy and so gain less weight. In many Western countries, many people also eat a diet that is high in fat and cholesterol. This raises the possibility that drugs that block the LXRα and LXRβ receptors in sensory neurons in humans could help to treat or prevent obesity, although further work will be needed to investigate this. DOI:http://dx.doi.org/10.7554/eLife.06667.002
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Affiliation(s)
- Virginie Mansuy-Aubert
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Laurent Gautron
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Syann Lee
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Angie L Bookout
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Christine Kusminski
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Kai Sun
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Yuan Zhang
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - David J Mangelsdorf
- Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joel K Elmquist
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
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Abstract
INTRODUCTION Although there has been great progress achieved by the use of intensive statin therapy, the burden of atherosclerotic cardiovascular disease (CVD) remains high. This has initiated the search for novel high-density lipoprotein (HDL)-based therapeutics. Recent years have witnessed a shift from traditional raising HDL-C levels to enhancing HDL functionality, in which the process of reverse cholesterol transport (RCT) has acquired much attention. AREAS COVERED In this review, the authors describe the key factors involved in RCT process for potential drug targets to reduce the CVD risk. Furthermore, the review provides a summary of the effective screening methods that have been developed to target RCT and their applications. This review also introduces some new strategies currently being clinically developed, which have the potential to improve HDL function in the RCT process. EXPERT OPINION It is rational that the functionality of HDL is more important than the plasma HDL-C level in the evaluation of pharmacological treatment in atherosclerosis. HDL-based strategies designed to promote macrophage RCT are a major area of current drug discovery and development for atherosclerotic diseases. A better understanding of the functionality of HDL and its relationship with atherosclerosis will expand our knowledge of the role of HDL in lipid metabolism, holding promise for a future successful HDL-based therapy.
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Affiliation(s)
- Yu Du
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College , No.1 Tiantan Xili, Beijing 100050 , China
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18
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Li H, Yang L, Yang H, Sun S, Liu H, Wu Q, Chen J, Zhuang T. Rice protein regulates HDL metabolism-related gene expression and enzyme activity in adult rats. FOOD BIOSCI 2014; 8:1-7. [DOI: 10.1016/j.fbio.2014.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Calkin AC, Lee SD, Kim J, Van Stijn CMW, Wu XH, Lusis AJ, Hong C, Tangirala RI, Tontonoz P. Transgenic expression of dominant-active IDOL in liver causes diet-induced hypercholesterolemia and atherosclerosis in mice. Circ Res 2014; 115:442-9. [PMID: 24935961 DOI: 10.1161/circresaha.115.304440] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [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] [Indexed: 01/21/2023]
Abstract
RATIONALE The E3 ubiquitin ligase inducible degrader of the low-density lipoprotein receptor (IDOL) triggers lysosomal degradation of the low-density lipoprotein receptor. The tissue-specific effects of the IDOL pathway on plasma cholesterol and atherosclerosis have not been examined. OBJECTIVE Given that the liver is the primary determinant of plasma cholesterol levels, we sought to examine the consequence of effect of chronic liver-specific expression of a dominant-active form of IDOL in mice. METHODS AND RESULTS We expressed a degradation-resistant, dominant-active form of IDOL (super IDOL [sIDOL]) in C57Bl/6J mice from the liver-specific albumin promoter (L-sIDOL transgenics). L-sIDOL mice were fed a Western diet for 20 or 30 weeks and then analyzed for plasma lipid levels and atherosclerotic lesion formation. L-sIDOL mice showed dramatic reductions in hepatic low-density lipoprotein receptor protein and increased plasma low-density lipoprotein cholesterol levels on both chow and Western diets. Moreover, L-sIDOL mice developed marked atherosclerotic lesions when fed a Western diet. Lesion formation in L-sIDOL mice was more robust than in apolipoprotein E*3 Leiden mice and did not require the addition of cholate to the diet. Western diet-fed L-sIDOL mice had elevated expression of liver X receptor target genes and proinflammatory genes in their aortas. CONCLUSIONS Liver-specific expression of dominant-active IDOL is associated with hypercholesterolemia and a marked elevation in atherosclerotic lesions. Our results show that increased activity of the IDOL pathway in the liver can override other low-density lipoprotein receptor regulatory pathways leading to cardiovascular disease. L-sIDOL mice are a robust, dominantly inherited, diet-inducible model for the study of atherosclerosis.
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Affiliation(s)
- Anna C Calkin
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Stephen D Lee
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Jason Kim
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Caroline M W Van Stijn
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Xiao-Hui Wu
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Aldons J Lusis
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Cynthia Hong
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Rajendra I Tangirala
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.)
| | - Peter Tontonoz
- From the Departments of Pathology and Laboratory Medicine (A.C.C., S.D.L., X.-H.W., C.H., P.T.), Department of Medicine, Division of Endocrinology (J.K., C.M.W.V.S., R.I.T.), Department of Medicine, Division of Cardiology (X.-H.W., A.J.L.), and Departments of Human Genetics and Microbiology Immunology and Molecular Genetics (A.J.L.), David Geffen School of Medicine, University of California, Los Angeles; Howard Hughes Medical Institute, Los Angeles, CA (A.C.C., S.D.L., C.H., P.T.); and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (A.C.C.).
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Affiliation(s)
- Colin M. Tice
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Paul B. Noto
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Kristi Yi Fan
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Linghang Zhuang
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Deepak S. Lala
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Suresh B. Singh
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
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Sallam T, Ito A, Rong X, Kim J, van Stijn C, Chamberlain BT, Jung ME, Chao LC, Jones M, Gilliland T, Wu X, Su GL, Tangirala RK, Tontonoz P, Hong C. The macrophage LBP gene is an LXR target that promotes macrophage survival and atherosclerosis. J Lipid Res 2014; 55:1120-30. [PMID: 24671012 DOI: 10.1194/jlr.m047548] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [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: 01/29/2014] [Indexed: 01/25/2023] Open
Abstract
The liver X receptors (LXRs) are members of the nuclear receptor superfamily that regulate sterol metabolism and inflammation. We sought to identify previously unknown genes regulated by LXRs in macrophages and to determine their contribution to atherogenesis. Here we characterize a novel LXR target gene, the lipopolysaccharide binding protein (LBP) gene. Surprisingly, the ability of LXRs to control LBP expression is cell-type specific, occurring in macrophages but not liver. Treatment of macrophages with oxysterols or loading with modified LDL induces LBP in an LXR-dependent manner, suggesting a potential role for LBP in the cellular response to cholesterol overload. To investigate this further, we performed bone marrow transplant studies. After 18 weeks of Western diet feeding, atherosclerotic lesion burden was assessed revealing markedly smaller lesions in the LBP(-/-) recipients. Furthermore, loss of bone marrow LBP expression increased apoptosis in atherosclerotic lesions as determined by terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Supporting in vitro studies with isolated macrophages showed that LBP expression does not affect cholesterol efflux but promotes the survival of macrophages in the setting of cholesterol loading. The LBP gene is a macrophage-specific LXR target that promotes foam cell survival and atherogenesis.
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Affiliation(s)
- Tamer Sallam
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA
| | - Ayaka Ito
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA
| | - Xin Rong
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA
| | - Jason Kim
- Department of Medicine, Division of Endocrinology, University of California, Los Angeles, Los Angeles, CA
| | - Caroline van Stijn
- Department of Medicine, Division of Endocrinology, University of California, Los Angeles, Los Angeles, CA
| | - Brian T Chamberlain
- Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA
| | - Michael E Jung
- Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA
| | - Lily C Chao
- Saban Research Institute, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA
| | - Marius Jones
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA
| | - Thomas Gilliland
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA
| | - XiaoHui Wu
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Grace L Su
- Medical Service, Department of Veterans Affairs Medical Center, Ann Arbor, MI Department of Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Rajendra K Tangirala
- Department of Medicine, Division of Endocrinology, University of California, Los Angeles, Los Angeles, CA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA
| | - Cynthia Hong
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA
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Abstract
The nuclear receptor superfamily includes many receptors, identified based on their similarity to steroid hormone receptors but without a known ligand. The study of how these receptors are diversely regulated to interact with genomic regions to control a plethora of biological processes has provided critical insight into development, physiology, and the molecular pathology of disease. Here we provide a compendium of these so-called orphan receptors and focus on what has been learned about their modes of action, physiological functions, and therapeutic promise.
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Affiliation(s)
- Shannon E Mullican
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Abstract
Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans.
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Rőszer T, Menéndez-Gutiérrez MP, Cedenilla M, Ricote M. Retinoid X receptors in macrophage biology. Trends Endocrinol Metab 2013; 24:460-8. [PMID: 23701753 DOI: 10.1016/j.tem.2013.04.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/19/2013] [Accepted: 04/23/2013] [Indexed: 01/07/2023]
Abstract
Retinoid X receptors (RXRs) form a distinct and unique subclass within the nuclear receptor (NR) superfamily of ligand-dependent transcription factors. RXRs regulate a plethora of genetic programs, including cell differentiation, the immune response, and lipid and glucose metabolism. Recent advances reveal that RXRs are important regulators of macrophages, key players in inflammatory and metabolic disorders. This review outlines the versatility of RXR action in the control of macrophage gene transcription through its heterodimerization with other NRs or through RXR homodimerization. We also highlight the potential of RXR-controlled transcriptional programs as targets for the treatment of pathologies associated with altered macrophage function, such as atherosclerosis, insulin resistance, autoimmunity, and neurodegeneration.
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Affiliation(s)
- Tamás Rőszer
- Cardiovascular Development and Repair Department, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain
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Abstract
INTRODUCTION The development of small molecule agonists of the liver X receptors (LXRs) has been an area of interest for over a decade, given the critical role of those receptors in cholesterol metabolism, glucose homeostasis, inflammation, innate immunity and lipogenesis. Many potential indications have been characterized over time including atherosclerosis, diabetes, inflammation, Alzheimer's disease and cancer. However, concerns about the lipogenic effects of full LXRα/β agonists have required extensive efforts aimed at identifying LXRβ agonist with limited activity on the LXRα receptor to increase the safety margins. AREAS COVERED This review includes a summary of the LXR agonists that have reached the clinic and summarizes the patent applications for LXR modulators from September 2009 to December 2012 with emphasis on chemical matters, biological data associated with selected analogs and therapeutic indications. EXPERT OPINION As LXR agonists have the potential to be useful for many indications, the scientific community, despite setbacks due to on-target side effects, has maintained interest and devised strategies to overcome safety hurdles. While a clinical proof of concept still remains elusive, the recent advancement of compounds into the clinic highlights that acceptable safety margins in preclinical species have been achieved.
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Affiliation(s)
- Jon Loren
- Genomics Institute of the Novartis Research Foundation , 10675 John Jay Hopkins Drive, San Diego, CA 92121 , USA +001 858 332 4736 ;
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27
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Ishibashi M, Filomenko R, Rébé C, Chevriaux A, Varin A, Derangère V, Bessède G, Gambert P, Lagrost L, Masson D. Knock-down of the oxysterol receptor LXRα impairs cholesterol efflux in human primary macrophages: Lack of compensation by LXRβ activation. Biochem Pharmacol 2013; 86:122-9. [DOI: 10.1016/j.bcp.2012.12.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 11/24/2022]
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Ignatova ID, Angdisen J, Moran E, Schulman IG. Differential regulation of gene expression by LXRs in response to macrophage cholesterol loading. Mol Endocrinol 2013; 27:1036-47. [PMID: 23686114 DOI: 10.1210/me.2013-1051] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ability of cells to precisely control gene expression in response to intracellular and extracellular signals plays an important role in both normal physiology and in pathological settings. For instance, the accumulation of excess cholesterol by macrophages initiates a genetic response mediated by the liver X receptors (LXRs)-α (NR1H3) and LXRβ (NR1H2), which facilitates the transport of cholesterol out of cells to high-density lipoprotein particles. Studies using synthetic LXR agonists have also demonstrated that macrophage LXR activation simultaneously induces a second network of genes that promotes fatty acid and triglyceride synthesis that may support the detoxification of excess free cholesterol by storage in the ester form. We now show that treatment of human THP-1 macrophages with endogenous or synthetic LXR ligands stimulates both transcriptional and posttranscriptional pathways that result in the selective recruitment of the LXRα subtype to LXR-regulated promoters. Interestingly, when human or mouse macrophages are loaded with cholesterol under conditions that mimic the development of atherogenic macrophage foam cells, a selective LXR response is generated that induces genes mediating cholesterol transport but does not coordinately regulate genes involved in fatty acid synthesis. The gene-selective response to cholesterol loading occurs, even in the presence of LXRα binding to the promoter of the gene encoding the sterol regulatory element-binding protein-1c, the master transcriptional regulator of fatty acid synthesis. The ability of promoter bound LXRα to recruit RNA polymerase to the sterol regulatory element-binding protein-1c promoter, however, appears to be ligand selective.
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Affiliation(s)
- Irena D Ignatova
- Department of Pharmacology, University of Virginia, 1300 Jefferson Park Avenue, PO Box 800735, Charlottesville, Virginia 22908, USA.
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Kazeminasab F, Marandi M, Ghaedi K, Esfarjani F, Moshtaghian J. Endurance training enhances LXRα gene expression in Wistar male rats. Eur J Appl Physiol 2013; 113:2285-90. [PMID: 23674092 DOI: 10.1007/s00421-013-2658-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 05/03/2013] [Indexed: 10/26/2022]
Abstract
Liver X receptor α (LXRα) is a member of the ligand-activated transcription factor of nuclear hormonal receptor superfamily, whose activation leads to modulation in the expression of genes involved in cholesterol homeostasis including ATP-binding cassette transporter A1 (ABCA1), which plays a crucial role in plasma high-density lipoprotein cholesterol (HDL-C) remodeling. The purpose of this study was to investigate whether endurance training enhanced the expression level of liver LXRα gene. Twelve adult male Wistar rats (200-220 g) were divided into control and training groups. Training group received exercise on a motor-driven treadmill at 28 m/min (0 % grade) for 60 min/day, 5 days/week for 8 weeks. Twenty-four hours after the last exercise session, the rats were killed and blood was taken from the right ventricle of each rat. Plasma was collected for HDL-C, low-density lipoprotein cholesterol (LDL-C), TC and TG measurements. Furthermore, a portion of the liver of each rat was excised and washed in ice-cold saline and frozen in liquid nitrogen for assessment of LXRα and ABCA1 mRNA levels. Data indicated significant increase in both LXRα and ABCA1 mRNA levels in trained rats, compared to control rats. Plasma HDL-C concentration was significantly higher (P < 0.001) in trained rats at the end of treadmill exercise. However, there was a significant decrease in LDL-C (P < 0.003), TG, TC concentration, TC/HDL-C and LDL/HDL-C ratios in trained rats compared with those in the control group (P < 0.001). In conclusion, we found that endurance training induced significant elevation in LXRα gene expression, which correlated with enhanced levels of ABCA1 mRNA and plasma HDL-C concentration.
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Affiliation(s)
- Fatemeh Kazeminasab
- Department of Exercise Physiology, Faculty of Sport Sciences, University of Isfahan, Isfahan, Iran
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Chao LC, Soto E, Hong C, Ito A, Pei L, Chawla A, Conneely OM, Tangirala RK, Evans RM, Tontonoz P. Bone marrow NR4A expression is not a dominant factor in the development of atherosclerosis or macrophage polarization in mice. J Lipid Res 2013; 54:806-815. [PMID: 23288947 PMCID: PMC3617954 DOI: 10.1194/jlr.m034157] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The formation of the atherosclerotic lesion is a complex process influenced by an
array of inflammatory and lipid metabolism pathways. We previously demonstrated
that NR4A nuclear receptors are highly induced in macrophages in response to
inflammatory stimuli and modulate the expression of genes linked to inflammation
in vitro. Here we used mouse genetic models to assess the impact of NR4A
expression on atherosclerosis development and macrophage polarization.
Transplantation of wild-type, Nur77−/−, or
Nor1−/− null hematopoetic precursors into LDL
receptor (LDLR)−/− recipient mice led to comparable
development of atherosclerotic lesions after high-cholesterol diet. We also
observed comparable induction of genes linked to M1 and M2 responses in
wild-type and Nur77-null macrophages in response to lipopolysaccharides and
interleukin (IL)-4, respectively. In contrast, activation of the nuclear
receptor liver X receptor (LXR) strongly suppressed M1 responses, and ablation
of signal transductor and activator of transcription 6 (STAT6) strongly
suppressed M2 responses. Recent studies have suggested that alterations in
levels of Ly6Clo monocytes may be a contributor to inflammation and
atherosclerosis. In our study, loss of Nur77, but not Nor1, was associated with
decreased abundance of Ly6Clo monocytes, but this change was not
correlated with atherosclerotic lesion development. Collectively, our results
suggest that alterations in the Ly6Clo monocyte population and bone
marrow NR4A expression do not play dominant roles in macrophage polarization or
the development of atherosclerosis in mice.
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Affiliation(s)
- Lily C Chao
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Erin Soto
- Gene Expression Laboratory, Salk Institute for Biological Studies, San Diego, CA
| | - Cynthia Hong
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Ayaka Ito
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Liming Pei
- Gene Expression Laboratory, Salk Institute for Biological Studies, San Diego, CA
| | - Ajay Chawla
- Cardiovascular Research Institute, Departments of Physiology and Medicine, University of California at San Francisco, San Francisco, CA
| | - Orla M Conneely
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX
| | - Rajendra K Tangirala
- Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Studies, San Diego, CA; Howard Hughes Medical Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA; Howard Hughes Medical Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA
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Engelbertsen D, To F, Dunér P, Kotova O, Söderberg I, Alm R, Gomez MF, Nilsson J, Bengtsson E. Increased inflammation in atherosclerotic lesions of diabetic Akita-LDLr⁻/⁻ mice compared to nondiabetic LDLr⁻/⁻ mice. Exp Diabetes Res 2012; 2012:176162. [PMID: 23243415 DOI: 10.1155/2012/176162] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 10/09/2012] [Accepted: 10/12/2012] [Indexed: 12/19/2022]
Abstract
Background. Diabetes is associated with increased cardiovascular disease, but the underlying cellular and molecular mechanisms are poorly understood. One proposed mechanism is that diabetes aggravates atherosclerosis by enhancing plaque inflammation. The Akita mouse has recently been adopted as a relevant model for microvascular complications of diabetes. Here we investigate the development of atherosclerosis and inflammation in vessels of Akita mice on LDLr−/− background. Methods and Results. Akita-LDLr−/− and LDLr−/− mice were fed high-fat diet from 6 to 24 weeks of age. Blood glucose levels were higher in both male and female Akita-LDLr−/− mice (137% and 70%, resp.). Male Akita-LDLr−/− mice had markedly increased plasma cholesterol and triglyceride levels, a three-fold increase in atherosclerosis, and enhanced accumulation of macrophages and T-cells in plaques. In contrast, female Akita-LDLr−/− mice demonstrated a modest 29% increase in plasma cholesterol and no significant increase in triglycerides, atherosclerosis, or inflammatory cells in lesions. Male Akita-LDLr−/− mice had increased levels of plasma IL-1β compared to nondiabetic mice, whereas no such difference was seen between female diabetic and nondiabetic mice. Conclusion. Akita-LDLr−/− mice display considerable gender differences in the development of diabetic atherosclerosis. In addition, the increased atherosclerosis in male Akita-LDLr−/− mice is associated with an increase in inflammatory cells in lesions.
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Abstract
PURPOSE OF REVIEW Several studies have recently shown that haemoglobin drives a novel macrophage subset that is protected from foam cell formation. RECENT FINDINGS In a previously overlooked area, two centres have independently shown that heme and haemoglobin drive an atheroprotective macrophage subset. We compare and contrast the approaches and findings of the laboratories and discuss some of the underlying biology and implications, concentrating on the aspects of lipidological relevance. SUMMARY Treatments based on direct heme-mimetics or other agonists of this pathway have enormous potential for linked antioxidant protection via heme oxygenase 1 and reduced foam cell formation via liver X receptor, a potent combination for treating atherosclerosis.
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