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Korenfeld N, Gorbonos T, Romero Florian MC, Rotaro D, Goldberg D, Radushkevitz-Frishman T, Charni-Natan M, Bar-Shimon M, Cummins CL, Goldstein I. LXR-dependent enhancer activation regulates the temporal organization of the liver's response to refeeding leading to lipogenic gene overshoot. PLoS Biol 2024; 22:e3002735. [PMID: 39241209 PMCID: PMC11379474 DOI: 10.1371/journal.pbio.3002735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 07/04/2024] [Indexed: 09/08/2024] Open
Abstract
Transitions between the fed and fasted state are common in mammals. The liver orchestrates adaptive responses to feeding/fasting by transcriptionally regulating metabolic pathways of energy usage and storage. Transcriptional and enhancer dynamics following cessation of fasting (refeeding) have not been explored. We examined the transcriptional and chromatin events occurring upon refeeding in mice, including kinetic behavior and molecular drivers. We found that the refeeding response is temporally organized with the early response focused on ramping up protein translation while the later stages of refeeding drive a bifurcated lipid synthesis program. While both the cholesterol biosynthesis and lipogenesis pathways were inhibited during fasting, most cholesterol biosynthesis genes returned to their basal levels upon refeeding while most lipogenesis genes markedly overshoot above pre-fasting levels. Gene knockout, enhancer dynamics, and ChIP-seq analyses revealed that lipogenic gene overshoot is dictated by LXRα. These findings from unbiased analyses unravel the mechanism behind the long-known phenomenon of refeeding fat overshoot.
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Affiliation(s)
- Noga Korenfeld
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tali Gorbonos
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Maria C Romero Florian
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Dan Rotaro
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Dana Goldberg
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Talia Radushkevitz-Frishman
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Meital Charni-Natan
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Meirav Bar-Shimon
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Carolyn L Cummins
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Ido Goldstein
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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Deng H, Rao X, Zhang S, Chen L, Zong Y, Zhou R, Meng R, Dong X, Wu G, Li Q. Protein kinase CK2: An emerging regulator of cellular metabolism. Biofactors 2024; 50:624-633. [PMID: 38158592 DOI: 10.1002/biof.2032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/02/2023] [Indexed: 01/03/2024]
Abstract
The protein kinase casein kinase 2 (CK2) exerts its influence on the metabolism of three major cellular substances by phosphorylating essential protein molecules involved in various cellular metabolic pathways. These substances include hormones, especially insulin, rate-limiting enzymes, transcription factors of key genes, and cytokines. This regulatory role of CK2 is closely tied to important cellular processes such as cell proliferation and apoptosis. Additionally, tumor cells undergo metabolic reprogramming characterized by aerobic glycolysis, accelerated lipid β-oxidation, and abnormally active glutamine metabolism. In this context, CK2, which is overexpressed in various tumors, also plays a pivotal role. Hence, this review aims to summarize the regulatory mechanisms of CK2 in diverse metabolic pathways and tumor development, providing novel insights for the diagnosis, treatment, and prognosis of metabolism-related diseases and cancers.
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Affiliation(s)
- Huilin Deng
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinrui Rao
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sijia Zhang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Leichong Chen
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Zong
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Zhou
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Meng
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaorong Dong
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gang Wu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qianwen Li
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Savla SR, Prabhavalkar KS, Bhatt LK. Liver X Receptor: a potential target in the treatment of atherosclerosis. Expert Opin Ther Targets 2022; 26:645-658. [PMID: 36003057 DOI: 10.1080/14728222.2022.2117610] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Liver X receptors (LXRs) are master regulators of atherogenesis. Their anti-atherogenic potential has been attributed to their role in the inhibition of macrophage-mediated inflammation and promotion of reverse cholesterol transport. Owing to the significance of their anti-atherogenic potential, it is essential to develop and test new generation LXR agonists, both synthetic and natural, to identify potential LXR-targeted therapeutics for the future. AREAS COVERED This review describes the role of LXRs in atherosclerotic development, provides a summary of LXR agonists and future directions for atherosclerosis research. We searched PubMed, Scopus and Google Scholar for relevant reports, from last 10 years, using atherosclerosis, liver X receptor, and LXR agonist as keywords. EXPERT OPINION LXRα has gained widespread recognition as a regulator of cholesterol homeostasis and expression of inflammatory genes. Further research using models of cell type-specific knockout and specific agonist-targeted LXR isoforms is warranted. Enthusiasm for therapeutic value of LXR agonists has been tempered due to LXRα-mediated induction of hepatic lipogenesis. LXRα agonism and LXRβ targeting, gut-specific inverse LXR agonists, investigations combining LXR agonists with other lipogenesis mitigating agents, like IDOL antagonists and synthetic HDL, and targeting ABCA1, M2 macrophages and LXRα phosphorylation, remain as promising possibilities.
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Affiliation(s)
- Shreya R Savla
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai 400056, India
| | - Kedar S Prabhavalkar
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai 400056, India
| | - Lokesh K Bhatt
- Department of Pharmacology, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai 400056, India
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Thorne JL, Cioccoloni G. Nuclear Receptors and Lipid Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:83-105. [DOI: 10.1007/978-3-031-11836-4_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Kong M, Dong W, Zhu Y, Fan Z, Miao X, Guo Y, Li C, Duan Y, Lu Y, Li Z, Xu Y. Redox-sensitive activation of CCL7 by BRG1 in hepatocytes during liver injury. Redox Biol 2021; 46:102079. [PMID: 34454163 PMCID: PMC8406035 DOI: 10.1016/j.redox.2021.102079] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 07/04/2021] [Accepted: 07/20/2021] [Indexed: 12/14/2022] Open
Abstract
Liver injuries induced by various stimuli share in common an acute inflammatory response, in which circulating macrophages home to the liver parenchyma to participate in the regulation of repair, regeneration, and fibrosis. In the present study we investigated the role of hepatocyte-derived C-C motif ligand 7 (CCL7) in macrophage migration during liver injury focusing on its transcriptional regulation. We report that CCL7 expression was up-regulated in the liver by lipopolysaccharide (LPS) injection (acute liver injury) or methionine-and-choline-deficient (MCD) diet feeding (chronic liver injury) paralleling increased macrophage infiltration. CCL7 expression was also inducible in hepatocytes, but not in hepatic stellate cells or in Kupffer cells, by LPS treatment or exposure to palmitate in vitro. Hepatocyte-specific deletion of Brahma-related gene 1 (BRG1), a chromatin remodeling protein, resulted in a concomitant loss of CCL7 induction and macrophage infiltration in the murine livers. Of interest, BRG1-induced CCL7 transcription and macrophage migration was completely blocked by the antioxidant N-acetylcystine. Further analyses revealed that BRG1 interacted with activator protein 1 (AP-1) to regulate CCL7 transcription in hepatocytes in a redox-sensitive manner mediated in part by casein kinase 2 (CK2)-catalyzed phosphorylation of BRG1. Importantly, a positive correlation between BRG1/CCL7 expression and macrophage infiltration was identified in human liver biopsy specimens. In conclusion, our data unveil a novel role for BRG1 as a redox-sensitive activator of CCL7 transcription.
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Affiliation(s)
- Ming Kong
- Key Laboratory of Targeted Invention of Cardiovascular Disease and Collaborative Innovation Center for Cardiovascular Translational Medicine, Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Wenhui Dong
- Key Laboratory of Targeted Invention of Cardiovascular Disease and Collaborative Innovation Center for Cardiovascular Translational Medicine, Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Yuwen Zhu
- Key Laboratory of Targeted Invention of Cardiovascular Disease and Collaborative Innovation Center for Cardiovascular Translational Medicine, Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Zhiwen Fan
- Department of Pathology, Affiliated Nanjing Drum Tower Hospital of Nanjing University School of Medicine, Nanjing, China
| | - Xiulian Miao
- College of Life Sciences and Institute of Biomedical Research, Liaocheng University, China
| | - Yan Guo
- College of Life Sciences and Institute of Biomedical Research, Liaocheng University, China
| | - Chengping Li
- College of Life Sciences and Institute of Biomedical Research, Liaocheng University, China
| | - Yunfei Duan
- Department of Hepatobiliary and Pancreatic Surgery, The First People's Hospital of Changzhou, The Third Hospital Affiliated to Soochow University, Changzhou, China
| | - Yunjie Lu
- Department of Hepatobiliary and Pancreatic Surgery, The First People's Hospital of Changzhou, The Third Hospital Affiliated to Soochow University, Changzhou, China.
| | - Zilong Li
- State Key Laboratory of Natural Medicines, Department of Pharmacology, China Pharmaceutical University, Nanjing, China.
| | - Yong Xu
- Key Laboratory of Targeted Invention of Cardiovascular Disease and Collaborative Innovation Center for Cardiovascular Translational Medicine, Department of Pathophysiology, Nanjing Medical University, Nanjing, China; College of Life Sciences and Institute of Biomedical Research, Liaocheng University, China.
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6
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Nuclear Receptors and Clock Components in Cardiovascular Diseases. Int J Mol Sci 2021; 22:ijms22189721. [PMID: 34575881 PMCID: PMC8468608 DOI: 10.3390/ijms22189721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/04/2021] [Accepted: 09/06/2021] [Indexed: 12/21/2022] Open
Abstract
Cardiovascular diseases (CVD) are still the first cause of death worldwide. Their main origin is the development of atherosclerotic plaque, which consists in the accumulation of lipids and inflammatory leucocytes within the vascular wall of large vessels. Beyond dyslipidemia, diabetes, obesity, hypertension and smoking, the alteration of circadian rhythms, in shift workers for instance, has recently been recognized as an additional risk factor. Accordingly, targeting a pro-atherogenic pathway at the right time window, namely chronotherapy, has proven its efficiency in reducing plaque progression without affecting healthy tissues in mice, thus providing the rationale of such an approach to treat CVD and to reduce drug side effects. Nuclear receptors are transcriptional factors involved in the control of many physiological processes. Among them, Rev-erbs and RORs control metabolic homeostasis, inflammatory processes and the biological clock. In this review, we discuss the opportunity to dampen atherosclerosis progression by targeting such ligand-activated core clock components in a (chrono-)therapeutic approach in order to treat CVD.
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Voisin M, Shrestha E, Rollet C, Nikain CA, Josefs T, Mahé M, Barrett TJ, Chang HR, Ruoff R, Schneider JA, Garabedian ML, Zoumadakis C, Yun C, Badwan B, Brown EJ, Mar AC, Schneider RJ, Goldberg IJ, Pineda-Torra I, Fisher EA, Garabedian MJ. Inhibiting LXRα phosphorylation in hematopoietic cells reduces inflammation and attenuates atherosclerosis and obesity in mice. Commun Biol 2021; 4:420. [PMID: 33772096 PMCID: PMC7997930 DOI: 10.1038/s42003-021-01925-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 02/26/2021] [Indexed: 12/25/2022] Open
Abstract
Atherosclerosis and obesity share pathological features including inflammation mediated by innate and adaptive immune cells. LXRα plays a central role in the transcription of inflammatory and metabolic genes. LXRα is modulated by phosphorylation at serine 196 (LXRα pS196), however, the consequences of LXRα pS196 in hematopoietic cell precursors in atherosclerosis and obesity have not been investigated. To assess the importance of LXRα phosphorylation, bone marrow from LXRα WT and S196A mice was transplanted into Ldlr-/- mice, which were fed a western diet prior to evaluation of atherosclerosis and obesity. Plaques from S196A mice showed reduced inflammatory monocyte recruitment, lipid accumulation, and macrophage proliferation. Expression profiling of CD68+ and T cells from S196A mouse plaques revealed downregulation of pro-inflammatory genes and in the case of CD68+ upregulation of mitochondrial genes characteristic of anti-inflammatory macrophages. Furthermore, S196A mice had lower body weight and less visceral adipose tissue; this was associated with transcriptional reprograming of the adipose tissue macrophages and T cells, and resolution of inflammation resulting in less fat accumulation within adipocytes. Thus, reducing LXRα pS196 in hematopoietic cells attenuates atherosclerosis and obesity by reprogramming the transcriptional activity of LXRα in macrophages and T cells to promote an anti-inflammatory phenotype.
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Affiliation(s)
- Maud Voisin
- Department of Microbiology, NYU School of Medicine, New York, NY, USA
| | - Elina Shrestha
- Department of Microbiology, NYU School of Medicine, New York, NY, USA
| | - Claire Rollet
- Department of Microbiology, NYU School of Medicine, New York, NY, USA
| | - Cyrus A Nikain
- Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, Department of Medicine, NYU School of Medicine, New York, NY, USA
| | - Tatjana Josefs
- Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, Department of Medicine, NYU School of Medicine, New York, NY, USA
| | - Mélanie Mahé
- Department of Microbiology, NYU School of Medicine, New York, NY, USA
| | - Tessa J Barrett
- Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, Department of Medicine, NYU School of Medicine, New York, NY, USA
| | - Hye Rim Chang
- Division of Endocrinology, Department of Medicine, NYU School of Medicine, New York, NY, USA
| | - Rachel Ruoff
- Department of Microbiology, NYU School of Medicine, New York, NY, USA
| | | | - Michela L Garabedian
- Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, Department of Medicine, NYU School of Medicine, New York, NY, USA
| | | | - Chi Yun
- Ordaos, Inc, New York, NY, USA
| | | | - Emily J Brown
- Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, Department of Medicine, NYU School of Medicine, New York, NY, USA
| | - Adam C Mar
- Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, USA
- Neuroscience Institute, New York University Medical Center, New York, NY, USA
| | | | - Ira J Goldberg
- Division of Endocrinology, Department of Medicine, NYU School of Medicine, New York, NY, USA
| | - Inés Pineda-Torra
- Centre for Cardiometabolic and Vascular Science, University College of London, London, UK
| | - Edward A Fisher
- Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, Department of Medicine, NYU School of Medicine, New York, NY, USA.
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Russo-Savage L, Schulman IG. Liver X receptors and liver physiology. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166121. [PMID: 33713792 DOI: 10.1016/j.bbadis.2021.166121] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 12/29/2022]
Abstract
The liver x receptors LXRα (NR1H3) and LXRβ (NR1H2) are members of the nuclear hormone receptor superfamily of ligand dependent transcription factors that regulate transcription in response to the direct binding of cholesterol derivatives. Studies using genetic knockouts and synthetic ligands have defined the LXRs as important modulators of lipid homeostasis throughout the body. This review focuses on the control of cholesterol and fatty acid metabolism by LXRs in the liver and how modifying LXR activity can influence the pathology of liver diseases.
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Affiliation(s)
- Lillian Russo-Savage
- Department of Pharmacology, University of Virginia, School of Medicine, United States of America
| | - Ira G Schulman
- Department of Pharmacology, University of Virginia, School of Medicine, United States of America.
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Duez H, Pourcet B. Nuclear Receptors in the Control of the NLRP3 Inflammasome Pathway. Front Endocrinol (Lausanne) 2021; 12:630536. [PMID: 33716981 PMCID: PMC7947301 DOI: 10.3389/fendo.2021.630536] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/04/2021] [Indexed: 12/13/2022] Open
Abstract
The innate immune system is the first line of defense specialized in the clearing of invaders whether foreign elements like microbes or self-elements that accumulate abnormally including cellular debris. Inflammasomes are master regulators of the innate immune system, especially in macrophages, and are key sensors involved in maintaining cellular health in response to cytolytic pathogens or stress signals. Inflammasomes are cytoplasmic complexes typically composed of a sensor molecule such as NOD-Like Receptors (NLRs), an adaptor protein including ASC and an effector protein such as caspase 1. Upon stimulation, inflammasome complex components associate to promote the cleavage of the pro-caspase 1 into active caspase-1 and the subsequent activation of pro-inflammatory cytokines including IL-18 and IL-1β. Deficiency or overactivation of such important sensors leads to critical diseases including Alzheimer diseases, chronic inflammatory diseases, cancers, acute liver diseases, and cardiometabolic diseases. Inflammasomes are tightly controlled by a two-step activation regulatory process consisting in a priming step, which activates the transcription of inflammasome components, and an activation step which leads to the inflammasome complex formation and the subsequent cleavage of pro-IL1 cytokines. Apart from the NF-κB pathway, nuclear receptors have recently been proposed as additional regulators of this pathway. This review will discuss the role of nuclear receptors in the control of the NLRP3 inflammasome and the putative beneficial effect of new modulators of inflammasomes in the treatment of inflammatory diseases including colitis, fulminant hepatitis, cardiac ischemia-reperfusion and brain diseases.
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10
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Hesperetin inhibits foam cell formation and promotes cholesterol efflux in THP-1-derived macrophages by activating LXRα signal in an AMPK-dependent manner. J Physiol Biochem 2021; 77:405-417. [PMID: 34212313 PMCID: PMC8367930 DOI: 10.1007/s13105-020-00783-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 12/26/2020] [Indexed: 12/12/2022]
Abstract
Cholesterol efflux from macrophages is the first step of reverse cholesterol transport (RCT), whose increase inhibits cholesterol accumulation and foam cell formation to suppress atherogenesis. Hesperetin has been reported to exert several protective effects on cardiovascular diseases, while little is known about the role of hesperetin and its underlying mechanism in macrophage foam cell formation. In this study, we sought to investigate the potential effects of hesperetin on foam cell formation and cholesterol efflux by using human macrophages, focusing on liver X receptor alpha (LXRα) and AMPK. We found that hesperetin treatment reduced foam cell formation, intracellular cholesterol levels and the cholesterol esterification rate, and increased cholesterol efflux in THP-1 macrophages. Hesperetin increased the levels of LXRα protein and its targets, including ABCA1, ABCG1, SR-BI, and phosphorylated-AMPK. Meanwhile, the hesperetin-induced increase in LXRα expression was further increased by the AMPK agonist and inhibited by an AMPK inhibitor. Meanwhile, hesperetin increased the levels of LXRα mRNA and its target genes, all of which were decreased in cells transfected with the AMPKα1/α2 small interfering RNA (siRNA). Furthermore, the hesperetin-induced inhibition of foam cell formation and promotion of cholesterol efflux were decreased by transfection of AMPKα1/α2 siRNA. In conclusions, We are the first to report that hesperetin activate AMPK in THP-1-derived macrophages. This activation upregulats LXRα and its targets, including ABCA1, ABCG1 and SR-BI, which significantly inhibits foam cell formation and promotes cholesterol efflux. Our results highlight the therapeutic potential of hesperetin to possibly reduce foam cell formation. This new mechanism might contribute the anti-atherogenic effects of hesperetin.
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11
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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] [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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12
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Larson SR, Bortell N, Illies A, Crisler WJ, Matsuda JL, Lenz LL. Myeloid Cell CK2 Regulates Inflammation and Resistance to Bacterial Infection. Front Immunol 2020; 11:590266. [PMID: 33363536 PMCID: PMC7752951 DOI: 10.3389/fimmu.2020.590266] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/05/2020] [Indexed: 12/27/2022] Open
Abstract
Kinase activity plays an essential role in the regulation of immune cell defenses against pathogens. The protein kinase CK2 (formerly casein kinase II) is an evolutionarily conserved kinase with hundreds of identified substrates. CK2 is ubiquitously expressed in somatic and immune cells, but the roles of CK2 in regulation of immune cell function remain largely elusive. This reflects the essential role of CK2 in organismal development and limited prior work with conditional CK2 mutant murine models. Here, we generated mice with a conditional (floxed) allele of Csnk2a, which encodes the catalytic CK2α subunit of CK2. When crossed to Lyz2-cre mice, excision of Csnk2a sequence impaired CK2α expression in myeloid cells but failed to detectably alter myeloid cell development. By contrast, deficiency for CK2α increased inflammatory myeloid cell recruitment, activation, and resistance following systemic Listeria monocytogenes (Lm) infection. Results from mixed chimera experiments indicated that CK2α deficiency in only a subset of myeloid cells was not sufficient to reduce bacterial burdens. Nor did cell-intrinsic deficiency for CK2α suffice to alter accumulation or activation of monocytes and neutrophils in infected tissues. These data suggest that CK2α expression by Lyz2-expressing cells promotes inflammatory and anti-bacterial responses through effects in trans. Our results highlight previously undescribed suppressive effects of CK2 activity on inflammatory myeloid cell responses and illustrate that cell-extrinsic effects of CK2 can shape inflammatory and protective innate immune responses.
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Affiliation(s)
- Sandy R. Larson
- Immunology and Microbiology Department, University of Colorado School of Medicine, Aurora, CO, United States
| | - Nikki Bortell
- Immunology and Microbiology Department, University of Colorado School of Medicine, Aurora, CO, United States
| | - Alysha Illies
- Immunology and Microbiology Department, University of Colorado School of Medicine, Aurora, CO, United States
| | - William J. Crisler
- Immunology and Microbiology Department, University of Colorado School of Medicine, Aurora, CO, United States
| | - Jennifer L. Matsuda
- Department of Biomedical Research, National Jewish Health, Denver, CO, United States
| | - Laurel L. Lenz
- Immunology and Microbiology Department, University of Colorado School of Medicine, Aurora, CO, United States
- Department of Biomedical Research, National Jewish Health, Denver, CO, United States
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13
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Guerra B, Issinger OG. Role of Protein Kinase CK2 in Aberrant Lipid Metabolism in Cancer. Pharmaceuticals (Basel) 2020; 13:ph13100292. [PMID: 33027921 PMCID: PMC7601870 DOI: 10.3390/ph13100292] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 10/01/2020] [Accepted: 10/02/2020] [Indexed: 12/20/2022] Open
Abstract
Uncontrolled proliferation is a feature defining cancer and it is linked to the ability of cancer cells to effectively adapt their metabolic needs in response to a harsh tumor environment. Metabolic reprogramming is considered a hallmark of cancer and includes increased glucose uptake and processing, and increased glutamine utilization, but also the deregulation of lipid and cholesterol-associated signal transduction, as highlighted in recent years. In the first part of the review, we will (i) provide an overview of the major types of lipids found in eukaryotic cells and their importance as mediators of intracellular signaling pathways (ii) analyze the main metabolic changes occurring in cancer development and the role of oncogenic signaling in supporting aberrant lipid metabolism and (iii) discuss combination strategies as powerful new approaches to cancer treatment. The second part of the review will address the emerging role of CK2, a conserved serine/threonine protein kinase, in lipid homeostasis with an emphasis regarding its function in lipogenesis and adipogenesis. Evidence will be provided that CK2 regulates these processes at multiple levels. This suggests that its pharmacological inhibition combined with dietary restrictions and/or inhibitors of metabolic targets could represent an effective way to undermine the dependency of cancer cells on lipids to interfere with tumor progression.
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14
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Voisin M, Gage MC, Becares N, Shrestha E, Fisher EA, Pineda-Torra I, Garabedian MJ. LXRα Phosphorylation in Cardiometabolic Disease: Insight From Mouse Models. Endocrinology 2020; 161:bqaa089. [PMID: 32496563 PMCID: PMC7324054 DOI: 10.1210/endocr/bqaa089] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/29/2020] [Indexed: 01/12/2023]
Abstract
Posttranslational modifications, such as phosphorylation, are a powerful means by which the activity and function of nuclear receptors such as LXRα can be altered. However, despite the established importance of nuclear receptors in maintaining metabolic homeostasis, our understanding of how phosphorylation affects metabolic diseases is limited. The physiological consequences of LXRα phosphorylation have, until recently, been studied only in vitro or nonspecifically in animal models by pharmacologically or genetically altering the enzymes enhancing or inhibiting these modifications. Here we review recent reports on the physiological consequences of modifying LXRα phosphorylation at serine 196 (S196) in cardiometabolic disease, including nonalcoholic fatty liver disease, atherosclerosis, and obesity. A unifying theme from these studies is that LXRα S196 phosphorylation rewires the LXR-modulated transcriptome, which in turn alters physiological response to environmental signals, and that this is largely distinct from the LXR-ligand-dependent action.
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Affiliation(s)
- Maud Voisin
- Department of Microbiology, New York University School of Medicine, New York, New York, US
| | - Matthew C Gage
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Natalia Becares
- Centre of Clinical Pharmacology, Division of Medicine, University College of London, London, UK
| | - Elina Shrestha
- Department of Microbiology, New York University School of Medicine, New York, New York, US
| | - Edward A Fisher
- Department of Microbiology, New York University School of Medicine, New York, New York, US
- Department of Medicine, New York University School of Medicine, New York, New York, US
| | - Ines Pineda-Torra
- Centre of Cardiometabolic and Vascular Science, Division of Medicine, University College of London, London, UK
| | - Michael J Garabedian
- Department of Microbiology, New York University School of Medicine, New York, New York, US
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15
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Becares N, Gage MC, Voisin M, Shrestha E, Martin-Gutierrez L, Liang N, Louie R, Pourcet B, Pello OM, Luong TV, Goñi S, Pichardo-Almarza C, Røberg-Larsen H, Diaz-Zuccarini V, Steffensen KR, O'Brien A, Garabedian MJ, Rombouts K, Treuter E, Pineda-Torra I. Impaired LXRα Phosphorylation Attenuates Progression of Fatty Liver Disease. Cell Rep 2020; 26:984-995.e6. [PMID: 30673619 PMCID: PMC6344342 DOI: 10.1016/j.celrep.2018.12.094] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 11/01/2018] [Accepted: 12/20/2018] [Indexed: 01/21/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a very common indication for liver transplantation. How fat-rich diets promote progression from fatty liver to more damaging inflammatory and fibrotic stages is poorly understood. Here, we show that disrupting phosphorylation at Ser196 (S196A) in the liver X receptor alpha (LXRα, NR1H3) retards NAFLD progression in mice on a high-fat-high-cholesterol diet. Mechanistically, this is explained by key histone acetylation (H3K27) and transcriptional changes in pro-fibrotic and pro-inflammatory genes. Furthermore, S196A-LXRα expression reveals the regulation of novel diet-specific LXRα-responsive genes, including the induction of Ces1f, implicated in the breakdown of hepatic lipids. This involves induced H3K27 acetylation and altered LXR and TBLR1 cofactor occupancy at the Ces1f gene in S196A fatty livers. Overall, impaired Ser196-LXRα phosphorylation acts as a novel nutritional molecular sensor that profoundly alters the hepatic H3K27 acetylome and transcriptome during NAFLD progression placing LXRα phosphorylation as an alternative anti-inflammatory or anti-fibrotic therapeutic target. LXRαS196A induces liver steatosis and prevents cholesterol accumulation LXRαS196A reduces progression to hepatic inflammation and fibrosis LXRαS196A modulates hepatic chromatin acetylation LXRαS196A reveals unique dual LXRα phosphorylation and diet-responsive genes
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Affiliation(s)
- Natalia Becares
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK
| | - Matthew C Gage
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK
| | - Maud Voisin
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Elina Shrestha
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Lucia Martin-Gutierrez
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK
| | - Ning Liang
- Karolinska Institute, Centre for Innovative Medicine (CIMED), Department of Biosciences and Nutrition, 14183 Huddinge, Sweden
| | - Rikah Louie
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK
| | - Benoit Pourcet
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK
| | - Oscar M Pello
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK
| | - Tu Vinh Luong
- Department of Cellular Pathology, Royal Free London NHS Foundation Trust, London NW3 2QG, UK
| | - Saioa Goñi
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | | | | | | | - Knut R Steffensen
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, 14186 Huddinge, Sweden
| | - Alastair O'Brien
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK
| | - Michael J Garabedian
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Krista Rombouts
- Institute for Liver & Digestive Health, University College London, Royal Free, London NW3 2PF, UK
| | - Eckardt Treuter
- Karolinska Institute, Centre for Innovative Medicine (CIMED), Department of Biosciences and Nutrition, 14183 Huddinge, Sweden
| | - Inés Pineda-Torra
- Centre of Cardiometabolic Medicine, Division of Medicine, University College of London, London WC1 E6JF, UK.
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16
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Czimmerer Z, Halasz L, Nagy L. Unorthodox Transcriptional Mechanisms of Lipid-Sensing Nuclear Receptors in Macrophages: Are We Opening a New Chapter? Front Endocrinol (Lausanne) 2020; 11:609099. [PMID: 33362723 PMCID: PMC7758493 DOI: 10.3389/fendo.2020.609099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/11/2020] [Indexed: 12/25/2022] Open
Abstract
Work over the past 30 years has shown that lipid-activated nuclear receptors form a bridge between metabolism and immunity integrating metabolic and inflammatory signaling in innate immune cells. Ligand-induced direct transcriptional activation and protein-protein interaction-based transrepression were identified as the most common mechanisms of liganded-nuclear receptor-mediated transcriptional regulation. However, the integration of different next-generation sequencing-based methodologies including chromatin immunoprecipitation followed by sequencing and global run-on sequencing allowed to investigate the DNA binding and ligand responsiveness of nuclear receptors at the whole-genome level. Surprisingly, these studies have raised the notion that a major portion of lipid-sensing nuclear receptor cistromes are not necessarily responsive to ligand activation. Although the biological role of the ligand insensitive portion of nuclear receptor cistromes is largely unknown, recent findings indicate that they may play roles in the organization of chromatin structure, in the regulation of transcriptional memory, and the epigenomic modification of responsiveness to other microenvironmental signals in macrophages. In this review, we will provide an overview and discuss recent advances of our understanding of lipid-activated nuclear receptor-mediated non-classical or unorthodox actions in macrophages.
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Affiliation(s)
- Zsolt Czimmerer
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Laszlo Halasz
- Departments of Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, St. Petersburg, FL, United States
| | - Laszlo Nagy
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Departments of Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, St. Petersburg, FL, United States
- *Correspondence: Laszlo Nagy,
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17
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Disrupting LXRα phosphorylation promotes FoxM1 expression and modulates atherosclerosis by inducing macrophage proliferation. Proc Natl Acad Sci U S A 2018; 115:E6556-E6565. [PMID: 29950315 DOI: 10.1073/pnas.1721245115] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Macrophages are key immune cells for the initiation and development of atherosclerotic lesions. However, the macrophage regulatory nodes that determine how lesions progress in response to dietary challenges are not fully understood. Liver X receptors (LXRs) are sterol-regulated transcription factors that play a central role in atherosclerosis by integrating cholesterol homeostasis and immunity. LXR pharmacological activation elicits a robust antiatherosclerotic transcriptional program in macrophages that can be affected by LXRα S196 phosphorylation in vitro. To investigate the impact of these transcriptional changes in atherosclerosis development, we have generated mice carrying a Ser-to-Ala mutation in myeloid cells in the LDL receptor (LDLR)-deficient atherosclerotic background (M-S196ALdlr-KO). M-S196ALdlr-KO mice fed a high-fat diet exhibit increased atherosclerotic plaque burden and lesions with smaller necrotic cores and thinner fibrous caps. These diet-induced phenotypic changes are consistent with a reprogramed macrophage transcriptome promoted by LXRα-S196A during atherosclerosis development. Remarkably, expression of several proliferation-promoting factors, including the protooncogene FoxM1 and its targets, is induced by LXRα-S196A. This is consistent with increased proliferation of plaque-resident cells in M-S196ALdlr-KO mice. Moreover, disrupted LXRα phosphorylation increases expression of phagocytic molecules, resulting in increased apoptotic cell removal by macrophages, explaining the reduced necrotic cores. Finally, the macrophage transcriptome promoted by LXRα-S196A under dietary perturbation is markedly distinct from that revealed by LXR ligand activation, highlighting the singularity of this posttranslational modification. Overall, our findings demonstrate that LXRα phosphorylation at S196 is an important determinant of atherosclerotic plaque development through selective changes in gene transcription that affect multiple pathways.
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18
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Saenz J, Santa-María C, Reyes-Quiroz ME, Geniz I, Jiménez J, Sobrino F, Alba G. Grapefruit Flavonoid Naringenin Regulates the Expression of LXRα in THP-1 Macrophages by Modulating AMP-Activated Protein Kinase. Mol Pharm 2018; 15:1735-1745. [PMID: 29140707 DOI: 10.1021/acs.molpharmaceut.7b00797] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The present work investigates the modulation of grapefruit flavonoid naringenin over liver X receptor alpha (LXRα) and its target genes in THP-1 macrophages, focusing on AMP-activated protein kinase (AMPK) implication. Naringenin induced LXRα at mRNA and protein levels besides influencing the expression of LXRα target genes ABCA1, ABCG1 (ATP-binding cassette A1 and G1), and SREBP1c (sterol response element binding protein 1c) in THP-1 macrophages. The increased LXRα mRNA and protein expression was reverted when AMPK was inhibited by its chemical inhibitor, compound C or by transfection with AMPK α1 and α2 siRNA. Naringenin treatments were also able to promote reverse cholesterol transport in THP-1 cells, which is in line with the increase in the ABCA1 and ABCG1 expression found. Treatments with this flavonoid also inhibited cell migration in THP-1 cells. In conclusion, LXRα and its target genes are up-regulated by naringenin in an AMPK dependent manner in human macrophages. The enhancement in the expression of genes involved in cholesterol efflux may reveal a new mechanism by which this polyphenol can prevent atherosclerosis and foam cell progression.
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Affiliation(s)
- Javier Saenz
- Departamento de Bioquímica Médica y Biología Molecular , Universidad de Sevilla , 41004 Sevilla , Spain
| | - Consuelo Santa-María
- Departamento de Bioquímica y Biología Molecular , Universidad de Sevilla , 41004 Sevilla , Spain
| | - María Edith Reyes-Quiroz
- Departamento de Bioquímica Médica y Biología Molecular , Universidad de Sevilla , 41004 Sevilla , Spain
| | - Isabel Geniz
- Hospital Nuestra Señora de Valme , Servicio Andaluz de Salud , 41001 Sevilla , Spain
| | - Juan Jiménez
- Departamento de Bioquímica Médica y Biología Molecular , Universidad de Sevilla , 41004 Sevilla , Spain
| | - Francisco Sobrino
- Departamento de Bioquímica Médica y Biología Molecular , Universidad de Sevilla , 41004 Sevilla , Spain
| | - Gonzalo Alba
- Departamento de Bioquímica Médica y Biología Molecular , Universidad de Sevilla , 41004 Sevilla , Spain
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19
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Sáenz J, Alba G, Reyes-Quiroz ME, Geniz I, Jiménez J, Sobrino F, Santa-María C. Curcumin enhances LXRα in an AMP-activated protein kinase-dependent manner in human macrophages. J Nutr Biochem 2018; 54:48-56. [DOI: 10.1016/j.jnutbio.2017.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/11/2017] [Accepted: 11/11/2017] [Indexed: 12/19/2022]
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20
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Hiebl V, Ladurner A, Latkolik S, Dirsch VM. Natural products as modulators of the nuclear receptors and metabolic sensors LXR, FXR and RXR. Biotechnol Adv 2018; 36:1657-1698. [PMID: 29548878 DOI: 10.1016/j.biotechadv.2018.03.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/02/2018] [Accepted: 03/08/2018] [Indexed: 01/25/2023]
Abstract
Nuclear receptors (NRs) represent attractive targets for the treatment of metabolic syndrome-related diseases. In addition, natural products are an interesting pool of potential ligands since they have been refined under evolutionary pressure to interact with proteins or other biological targets. This review aims to briefly summarize current basic knowledge regarding the liver X (LXR) and farnesoid X receptors (FXR) that form permissive heterodimers with retinoid X receptors (RXR). Natural product-based ligands for these receptors are summarized and the potential of LXR, FXR and RXR as targets in precision medicine is discussed.
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Affiliation(s)
- Verena Hiebl
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
| | - Angela Ladurner
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria.
| | - Simone Latkolik
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
| | - Verena M Dirsch
- University of Vienna, Department of Pharmacognosy, Althanstrasse 14, 1090 Vienna, Austria
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21
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Becares N, Gage MC, Pineda-Torra I. Posttranslational Modifications of Lipid-Activated Nuclear Receptors: Focus on Metabolism. Endocrinology 2017; 158:213-225. [PMID: 27925773 PMCID: PMC5413085 DOI: 10.1210/en.2016-1577] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/02/2016] [Indexed: 12/18/2022]
Abstract
Posttranslational modifications (PTMs) occur to nearly all proteins, are catalyzed by specific enzymes, and are subjected to tight regulation. They have been shown to be a powerful means by which the function of proteins can be modified, resulting in diverse effects. Technological advances such as the increased sensitivity of mass spectrometry-based techniques and availability of mutant animal models have enhanced our understanding of the complexities of their regulation and the effect they have on protein function. However, the role that PTMs have in a pathological context still remains unknown for the most part. PTMs enable the modulation of nuclear receptor function in a rapid and reversible manner in response to varied stimuli, thereby dramatically altering their activity in some cases. This review focuses on acetylation, phosphorylation, SUMOylation, and O-GlcNAcylation, which are the 4 most studied PTMs affecting lipid-regulated nuclear receptor biology, as well as on the implications of such modifications on metabolic pathways under homeostatic and pathological situations. Moreover, we review recent studies on the modulation of PTMs as therapeutic targets for metabolic diseases.
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Affiliation(s)
- Natalia Becares
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, London, United Kingdom
| | - Matthew C Gage
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, London, United Kingdom
| | - Inés Pineda-Torra
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, London, United Kingdom
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22
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Chistiakov DA, Myasoedova VA, Revin VV, Orekhov AN, Bobryshev YV. The phenomenon of atherosclerosis reversal and regression: Lessons from animal models. Exp Mol Pathol 2017; 102:138-145. [PMID: 28108216 DOI: 10.1016/j.yexmp.2017.01.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/19/2016] [Accepted: 01/14/2017] [Indexed: 12/18/2022]
Abstract
Studies in non-rodent and murine models showed that atherosclerosis can be reversed. Atherosclerosis progression induced by high-fat or cholesterol-rich diet can be reduced and reversed to plaque regression after switching to a normal diet or through administration of lipid-lowering agents. The similar process should exist in humans after implementation of lipid-lowering therapy and as a result of targeting of small rupture-prone plaques that are major contributors for acute atherosclerotic complications. Lowering of low density lipoprotein (LDL) cholesterol and the activation of reverse cholesterol transport lead to a decline in foam cell content, to the depletion of plaque lipid reservoirs, a decrease in lesional macrophage numbers through the activation of macrophage emigration and, probably, apoptosis, dampening plaque inflammation, and the induction of anti-inflammatory macrophages involved in clearance of the necrotic core and plaque healing. By contrast, plaque regression is characterized by opposite events, leading to the retention of atherogenic LDL and oxidized LDL particles in the plaque, an increased flux of monocytes, the immobilization of macrophages in the intimal vascular tissues, and the propagation of intraplaque inflammation. Transfer of various apolipoprotein (apo) genes to spontaneously hypercholesterolemic mice deficient for either apoE or LDL receptor and, especially, the implementation of the transplantation murine model allowed studying molecular mechanisms of atherosclerotic regression, associated with the depletion of atherogenic lipids in the plaque, egress of macrophages and phenotypic switch of macrophages from the proinflammatory M1 to the anti-inflammatory M2.
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Affiliation(s)
- Dimitry A Chistiakov
- Department of Medical Nanobiotechnology, Pirogov Russian State Medical University, Moscow, Russia; Department of Molecular Genetic Diagnostics and Cell Biology, Institute of Pediatrics, Research Center for Children's Health, Moscow, Russia
| | - Veronika A Myasoedova
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, Russia; Institute for Atherosclerosis Research, Skolkovo Innovative Center, Moscow, Russia
| | - Victor V Revin
- N.P. Ogaryov Mordovian State University, Republic of Mordovia, Saransk 430005, Russia
| | - Alexander N Orekhov
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, Russia; Institute for Atherosclerosis Research, Skolkovo Innovative Center, Moscow, Russia; Department of Biophysics, Moscow State University, Moscow, Russia
| | - Yuri V Bobryshev
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, Russia; Institute for Atherosclerosis Research, Skolkovo Innovative Center, Moscow, Russia; School of Medical Sciences, University of New South Wales, NSW, Sydney, Australia; School of Medicine, University of Western Sydney, Campbelltown, NSW, Australia.
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23
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Ontsouka CE, Huang X, Aliyev E, Albrecht C. In vitro characterization and endocrine regulation of cholesterol and phospholipid transport in the mammary gland. Mol Cell Endocrinol 2017; 439:35-45. [PMID: 27760380 DOI: 10.1016/j.mce.2016.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/25/2016] [Accepted: 10/15/2016] [Indexed: 10/20/2022]
Abstract
Cell-based studies previously showed that the ATP-binding cassette transporter A1 (ABCA1) transfers cholesterol across mammary epithelial cells (MEC). Data for phospholipid transport are lacking, and it is unclear from which cellular source the transported cholesterol stems, whether this transport activates signaling pathways, and how lactogenic hormones regulate it. To clarify these aspects, lipid transport and expressional analyses were performed in bovine primary (bMEC) and/or immortalized (MAC-T) MEC cultures. Lipid efflux and ABCA1, ABCG1 and liver X receptorα mRNA levels were higher in MAC-T than bMEC. In MAC-T, the transported cholesterol originated mainly from the plasma membrane. ABCA1 dependent cholesterol efflux was higher than phosphatidylcholine efflux, was suppressed by probucol (ABCA1 inhibitor), AG490 (janus kinase-2 inhibitor), PD98059 (mitogen activated protein kinase kinase inhibitor) and pretreatment with β-cyclodextrin (lowering membrane cholesterol). Insulin was the only hormone significantly increasing cholesterol efflux. In conclusion, this study gives novel mechanistic and regulatory insights into the transport of cholesterol and phospholipids in MEC.
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Affiliation(s)
- Corneille Edgar Ontsouka
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland; Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
| | - Xiao Huang
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland; Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland
| | - Eldar Aliyev
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland; Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland.
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24
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Kemmerer M, Wittig I, Richter F, Brüne B, Namgaladze D. AMPK activates LXRα and ABCA1 expression in human macrophages. Int J Biochem Cell Biol 2016; 78:1-9. [DOI: 10.1016/j.biocel.2016.06.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/10/2016] [Accepted: 06/21/2016] [Indexed: 11/16/2022]
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25
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Lee JH, Kim H, Park SJ, Woo JH, Joe EH, Jou I. Small heterodimer partner SHP mediates liver X receptor (LXR)–dependent suppression of inflammatory signaling by promoting LXR SUMOylation specifically in astrocytes. Sci Signal 2016; 9:ra78. [DOI: 10.1126/scisignal.aaf4850] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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26
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Hamilton JP, Koganti L, Muchenditsi A, Pendyala VS, Huso D, Hankin J, Murphy RC, Huster D, Merle U, Mangels C, Yang N, Potter JJ, Mezey E, Lutsenko S. Activation of liver X receptor/retinoid X receptor pathway ameliorates liver disease in Atp7B(-/-) (Wilson disease) mice. Hepatology 2016; 63:1828-41. [PMID: 26679751 PMCID: PMC4874878 DOI: 10.1002/hep.28406] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/30/2015] [Accepted: 12/15/2015] [Indexed: 01/07/2023]
Abstract
UNLABELLED Wilson disease (WD) is a hepatoneurological disorder caused by mutations in the copper-transporter, ATP7B. Copper accumulation in the liver is a hallmark of WD. Current therapy is based on copper chelation, which decreases the manifestations of liver disease, but often worsens neurological symptoms. We demonstrate that in Atp7b(-/-) mice, an animal model of WD, liver function can be significantly improved without copper chelation. Analysis of transcriptional and metabolic changes in samples from WD patients and Atp7b(-/-) mice identified dysregulation of nuclear receptors (NRs), especially the liver X receptor (LXR)/retinoid X receptor heterodimer, as an important event in WD pathogenesis. Treating Atp7b(-/-) mice with the LXR agonist, T0901317, ameliorated disease manifestations despite significant copper overload. Genetic markers of liver fibrosis and inflammatory cytokines were significantly decreased, lipid profiles normalized, and liver function and histology were improved. CONCLUSIONS The results demonstrate the major role of an altered NR function in the pathogenesis of WD and suggest that modulation of NR activity should be explored as a supplementary approach to improving liver function in WD. (Hepatology 2016;63:1828-1841).
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Affiliation(s)
- JP Hamilton
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - L Koganti
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - A Muchenditsi
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - VS Pendyala
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - D Huso
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - J Hankin
- University of Colorado, Denver, CO
| | | | - D Huster
- Deakoness Hospital, Leipzig, Germany
| | - U Merle
- University of Heidelberg, Germany
| | - C Mangels
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - N Yang
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - JJ Potter
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - E Mezey
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S. Lutsenko
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD,Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
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27
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Pourcet B, Gage MC, León TE, Waddington KE, Pello OM, Steffensen KR, Castrillo A, Valledor AF, Pineda-Torra I. The nuclear receptor LXR modulates interleukin-18 levels in macrophages through multiple mechanisms. Sci Rep 2016; 6:25481. [PMID: 27149934 PMCID: PMC4858669 DOI: 10.1038/srep25481] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 04/19/2016] [Indexed: 12/30/2022] Open
Abstract
IL-18 is a member of the IL-1 family involved in innate immunity and inflammation. Deregulated levels of IL-18 are involved in the pathogenesis of multiple disorders including inflammatory and metabolic diseases, yet relatively little is known regarding its regulation. Liver X receptors or LXRs are key modulators of macrophage cholesterol homeostasis and immune responses. Here we show that LXR ligands negatively regulate LPS-induced mRNA and protein expression of IL-18 in bone marrow-derived macrophages. Consistent with this being an LXR-mediated process, inhibition is abolished in the presence of a specific LXR antagonist and in LXR-deficient macrophages. Additionally, IL-18 processing of its precursor inactive form to its bioactive state is inhibited by LXR through negative regulation of both pro-caspase 1 expression and activation. Finally, LXR ligands further modulate IL-18 levels by inducing the expression of IL-18BP, a potent endogenous inhibitor of IL-18. This regulation occurs via the transcription factor IRF8, thus identifying IL-18BP as a novel LXR and IRF8 target gene. In conclusion, LXR activation inhibits IL-18 production through regulation of its transcription and maturation into an active pro-inflammatory cytokine. This novel regulation of IL-18 by LXR could be applied to modulate the severity of IL-18 driven metabolic and inflammatory disorders.
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Affiliation(s)
- Benoit Pourcet
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, 5 University Street, London, WC1 E6JF, United Kingdom
| | - Matthew C Gage
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, 5 University Street, London, WC1 E6JF, United Kingdom
| | - Theresa E León
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, 5 University Street, London, WC1 E6JF, United Kingdom
| | - Kirsty E Waddington
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, 5 University Street, London, WC1 E6JF, United Kingdom
| | - Oscar M Pello
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, 5 University Street, London, WC1 E6JF, United Kingdom
| | - Knut R Steffensen
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institut, Huddinge, Sweden
| | - Antonio Castrillo
- Instituto de Investigaciones Biomedicas "Alberto Sols" Consejo Superior de Investigaciones Científicas (CSIC) de Madrid, Unidad de Biomedicina (Unidad Asociada al CSIC), Instituto Universitario de Investigaciones Biomedicas y Sanitarias (IUIBS) de la Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain
| | - Annabel F Valledor
- School of Biology, University of Barcelona, Diagonal 643, Planta 3, 08028 Barcelona, Spain
| | - Inés Pineda-Torra
- Centre for Clinical Pharmacology, Division of Medicine, University College of London, 5 University Street, London, WC1 E6JF, United Kingdom
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28
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Shrestha E, Hussein MA, Savas JN, Ouimet M, Barrett TJ, Leone S, Yates JR, Moore KJ, Fisher EA, Garabedian MJ. Poly(ADP-ribose) Polymerase 1 Represses Liver X Receptor-mediated ABCA1 Expression and Cholesterol Efflux in Macrophages. J Biol Chem 2016; 291:11172-84. [PMID: 27026705 DOI: 10.1074/jbc.m116.726729] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Indexed: 11/06/2022] Open
Abstract
Liver X receptors (LXR) are oxysterol-activated nuclear receptors that play a central role in reverse cholesterol transport through up-regulation of ATP-binding cassette transporters (ABCA1 and ABCG1) that mediate cellular cholesterol efflux. Mouse models of atherosclerosis exhibit reduced atherosclerosis and enhanced regression of established plaques upon LXR activation. However, the coregulatory factors that affect LXR-dependent gene activation in macrophages remain to be elucidated. To identify novel regulators of LXR that modulate its activity, we used affinity purification and mass spectrometry to analyze nuclear LXRα complexes and identified poly(ADP-ribose) polymerase-1 (PARP-1) as an LXR-associated factor. In fact, PARP-1 interacted with both LXRα and LXRβ. Both depletion of PARP-1 and inhibition of PARP-1 activity augmented LXR ligand-induced ABCA1 expression in the RAW 264.7 macrophage line and primary bone marrow-derived macrophages but did not affect LXR-dependent expression of other target genes, ABCG1 and SREBP-1c. Chromatin immunoprecipitation experiments confirmed PARP-1 recruitment at the LXR response element in the promoter of the ABCA1 gene. Further, we demonstrated that LXR is poly(ADP-ribosyl)ated by PARP-1, a potential mechanism by which PARP-1 influences LXR function. Importantly, the PARP inhibitor 3-aminobenzamide enhanced macrophage ABCA1-mediated cholesterol efflux to the lipid-poor apolipoprotein AI. These findings shed light on the important role of PARP-1 on LXR-regulated lipid homeostasis. Understanding the interplay between PARP-1 and LXR may provide insights into developing novel therapeutics for treating atherosclerosis.
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Affiliation(s)
- Elina Shrestha
- From the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Maryem A Hussein
- From the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Jeffery N Savas
- the Department of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611
| | - Mireille Ouimet
- the Department of Medicine, Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, New York University School of Medicine, New York, New York 10016, and
| | - Tessa J Barrett
- the Department of Medicine, Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, New York University School of Medicine, New York, New York 10016, and
| | - Sarah Leone
- From the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - John R Yates
- the Department of Chemical Physiology, Scripps Research Institute, La Jolla, California 92037
| | - Kathryn J Moore
- the Department of Medicine, Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, New York University School of Medicine, New York, New York 10016, and
| | - Edward A Fisher
- the Department of Medicine, Division of Cardiology, Marc and Ruti Bell Program in Vascular Biology, New York University School of Medicine, New York, New York 10016, and
| | - Michael J Garabedian
- From the Department of Microbiology, New York University School of Medicine, New York, New York 10016,
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29
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Thiagarajan D, Ananthakrishnan R, Zhang J, O'Shea KM, Quadri N, Li Q, Sas K, Jing X, Rosario R, Pennathur S, Schmidt AM, Ramasamy R. Aldose Reductase Acts as a Selective Derepressor of PPARγ and the Retinoic Acid Receptor. Cell Rep 2016; 15:181-196. [PMID: 27052179 DOI: 10.1016/j.celrep.2016.02.086] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 01/13/2016] [Accepted: 02/24/2016] [Indexed: 01/04/2023] Open
Abstract
Histone deacetylase 3 (HDAC3), a chromatin-modifying enzyme, requires association with the deacetylase-containing domain (DAD) of the nuclear receptor corepressors NCOR1 and SMRT for its stability and activity. Here, we show that aldose reductase (AR), the rate-limiting enzyme of the polyol pathway, competes with HDAC3 to bind the NCOR1/SMRT DAD. Increased AR expression leads to HDAC3 degradation followed by increased PPARγ signaling, resulting in lipid accumulation in the heart. AR also downregulates expression of nuclear corepressor complex cofactors including Gps2 and Tblr1, thus affecting activity of the nuclear corepressor complex itself. Though AR reduces HDAC3-corepressor complex formation, it specifically derepresses the retinoic acid receptor (RAR), but not other nuclear receptors such as the thyroid receptor (TR) and liver X receptor (LXR). In summary, this work defines a distinct role for AR in lipid and retinoid metabolism through HDAC3 regulation and consequent derepression of PPARγ and RAR.
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Affiliation(s)
- Devi Thiagarajan
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Radha Ananthakrishnan
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Jinghua Zhang
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Karen M O'Shea
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Nosirudeen Quadri
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Qing Li
- Columbia University Medical Center, New York, NY 10032, USA
| | - Kelli Sas
- Division of Nephrology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Xiao Jing
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Rosa Rosario
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Subramaniam Pennathur
- Division of Nephrology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Ann Marie Schmidt
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Ravichandran Ramasamy
- Diabetes Research Program, Department of Medicine, New York University Langone Medical Center, New York, NY 10016, USA.
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30
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Hussein MA, Shrestha E, Ouimet M, Barrett TJ, Leone S, Moore KJ, Hérault Y, Fisher EA, Garabedian MJ. LXR-Mediated ABCA1 Expression and Function Are Modulated by High Glucose and PRMT2. PLoS One 2015; 10:e0135218. [PMID: 26288135 PMCID: PMC4545936 DOI: 10.1371/journal.pone.0135218] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/20/2015] [Indexed: 01/11/2023] Open
Abstract
High cholesterol and diabetes are major risk factors for atherosclerosis. Regression of atherosclerosis is mediated in part by the Liver X Receptor (LXR) through the induction of genes involved in cholesterol transport and efflux. In the context of diabetes, regression of atherosclerosis is impaired. We proposed that changes in glucose levels modulate LXR-dependent gene expression. Using a mouse macrophage cell line (RAW 264.7) and primary bone marrow derived macrophages (BMDMs) cultured in normal or diabetes relevant high glucose conditions we found that high glucose inhibits the LXR-dependent expression of ATP-binding cassette transporter A1 (ABCA1), but not ABCG1. To probe for this mechanism, we surveyed the expression of a host of chromatin-modifying enzymes and found that Protein Arginine Methyltransferase 2 (PRMT2) was reduced in high compared to normal glucose conditions. Importantly, ABCA1 expression and ABCA1-mediated cholesterol efflux were reduced in Prmt2-/- compared to wild type BMDMs. Monocytes from diabetic mice also showed decreased expression of Prmt2 compared to non-diabetic counterparts. Thus, PRMT2 represents a glucose-sensitive factor that plays a role in LXR-mediated ABCA1-dependent cholesterol efflux and lends insight to the presence of increased atherosclerosis in diabetic patients.
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Affiliation(s)
- Maryem A. Hussein
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
| | - Elina Shrestha
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
| | - Mireille Ouimet
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Tessa J. Barrett
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Sarah Leone
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
| | - Kathryn J. Moore
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, 1 rue Laurent Fries, 67404, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France; Institut Clinique de la Souris, ICS, 1 rue Laurent Fries, 67404, Illkirch, France
| | - Edward A. Fisher
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Michael J. Garabedian
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
- * E-mail:
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31
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Abstract
The liver X receptors (LXRs), LXRα and LXRβ, are transcription factors with well-established roles in the regulation of lipid metabolism and cholesterol homeostasis. In addition, LXRs influence innate and adaptive immunity, including responses to inflammatory stimuli, proliferation and differentiation, migration, apoptosis and survival. However, the majority of work describing the role of LXRs in immune cells has been carried out in mouse models, and there are a number of known species-specific differences concerning LXR function. Here we review what is known about the role of LXRs in human immune cells, demonstrating the importance of these receptors in the integration of lipid metabolism and immune function, but also highlighting the need for a better understanding of the species, isoform, and cell-type specific effects of LXR activation.
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32
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Huwait EA, Singh NN, Michael DR, Davies TS, Moss JW, Ramji DP. Protein Kinase C Is Involved in the Induction of ATP-Binding Cassette Transporter A1 Expression by Liver X Receptor/Retinoid X Receptor Agonist in Human Macrophages. J Cell Biochem 2015; 116:2032-8. [DOI: 10.1002/jcb.25157] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 03/03/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Etimad A. Huwait
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Nishi N. Singh
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Daryn R. Michael
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Thomas S. Davies
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Joe W.E. Moss
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Dipak P. Ramji
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
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33
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Modulation of Macrophage Gene Expression via Liver X Receptor α Serine 198 Phosphorylation. Mol Cell Biol 2015; 35:2024-34. [PMID: 25825525 DOI: 10.1128/mcb.00985-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 03/19/2015] [Indexed: 11/20/2022] Open
Abstract
In mouse models of atherosclerosis, normalization of hyperlipidemia promotes macrophage emigration and regression of atherosclerotic plaques in part by liver X receptor (LXR)-mediated induction of the chemokine receptor CCR7. Here we report that LXRα serine 198 (S198) phosphorylation modulates CCR7 expression. Low levels of S198 phosphorylation are observed in plaque macrophages in the regression environment where high levels of CCR7 expression are observed. Consistent with these findings, CCR7 gene expression in human and mouse macrophages cell lines is induced when LXRα at S198 is nonphosphorylated. In bone marrow-derived macrophages (BMDMs), we also observed induction of CCR7 by ligands that promote nonphosphorylated LXRα S198, and this was lost in LXR-deficient BMDMs. LXRα occupancy at the CCR7 promoter is enhanced and histone modifications associated with gene repression are reduced in RAW264.7 cells expressing nonphosphorylated LXRα (RAW-LXRα S198A) compared to RAW264.7 cells expressing wild-type (WT) phosphorylated LXRα (RAW-LXRα WT). Expression profiling of ligand-treated RAW-LXRα S198A cells compared to RAW-LXRα WT cells revealed induction of cell migratory and anti-inflammatory genes and repression of proinflammatory genes. Modeling of LXRα S198 in the nonphosphorylated and phosphorylated states identified phosphorylation-dependent conformational changes in the hinge region commensurate with the presence of sites for protein interaction. Therefore, gene transcription is regulated by LXRα S198 phosphorylation, including that of antiatherogenic genes such as CCR7.
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34
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Reyes-Quiroz ME, Alba G, Santa-María C, Saenz J, Geniz I, Jiménez J, Ramírez R, Martín-Nieto J, Pintado E, Sobrino F. Platelet-activating factor downregulates the expression of liver X receptor-α and its target genes in human neutrophils. FEBS J 2014; 281:970-82. [PMID: 24289152 DOI: 10.1111/febs.12662] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 10/22/2013] [Accepted: 11/22/2013] [Indexed: 01/11/2023]
Abstract
Liver X receptors (LXRs) are ligand-activated members of the nuclear receptor superfamily that regulate the expression of genes involved in lipid metabolism and inflammation, although their role in inflammation and immunity is less well known. It has been reported that oxysterols/LXRs may act as anti-inflammatory molecules, although opposite actions have also been reported. In this study, we investigated the effect of platelet-activating factor (PAF), a proinflammatory molecule, on LXRα signalling in human neutrophils. We found that PAF exerted an inhibitory effect on mRNA expression of TO901317-induced LXRα, ATP-binding cassette transporter A1, ATP-binding cassette transporter G1, and sterol response element binding protein 1c. This negative action was mediated by the PAF receptor, and was dependent on the release of reactive oxygen species elicited by PAF, as it was enhanced by pro-oxidant treatment and reversed by antioxidants. Current data also support the idea that PAF induces phosphorylation of the LXRα molecule in an extracellular signal-regulated kinase 1/2-mediated fashion. These results suggest that a possible mechanism by which PAF exerts its proinflammatory effect is through the downregulation of LXRα and its related genes, which supports the notion that LXRα ligands exert a modulatory role in the neutrophil-mediated inflammatory response.
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Affiliation(s)
- María E Reyes-Quiroz
- Departamento de Bioquímica Médica y Biología Molecular, Universidad de Sevilla, Spain
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35
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Luu W, Sharpe LJ, Gelissen IC, Brown AJ. The role of signalling in cellular cholesterol homeostasis. IUBMB Life 2013; 65:675-84. [PMID: 23847008 DOI: 10.1002/iub.1182] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 04/21/2013] [Indexed: 12/19/2022]
Abstract
Cholesterol is a vital lipid and performs diverse functions on a whole body and cellular level. However, excess cellular cholesterol is toxic, and thus, elegant mechanisms have evolved to tightly regulate this important lipid. The regulation of cholesterol homeostasis is an area of intense research, and the role that signalling plays is gradually becoming more widely recognised. Cholesterol homeostasis is achieved through intricate mechanisms involving synthesis, uptake, and efflux. Although there is a large body of work elucidating these cholesterol-related pathways, less is known about the role of signalling in these processes. Here, we discuss the variety of ways that signalling impacts on these modes and levels of cholesterol homeostasis, including transcriptional regulation. Most work thus far has investigated the role of kinases in cholesterol efflux (especially on ATP-binding cassette transporter A1, ABCA1), and therefore constitutes a major focus of this review. We also indicate further avenues to explore in the area of signalling in cellular cholesterol homeostasis.
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Affiliation(s)
- Winnie Luu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, NSW, Australia
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36
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Steffensen KR, Jakobsson T, Gustafsson JÅ. Targeting liver X receptors in inflammation. Expert Opin Ther Targets 2013; 17:977-90. [PMID: 23738533 DOI: 10.1517/14728222.2013.806490] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION The two oxysterol receptors, 'liver X receptors (LXRs)' LXRα and LXRβ, are amongst the emerging newer drug targets within the nuclear receptor family and targeting LXRs represents novel strategies needed for prevention and treatment of diseases where current therapeutics is inadequate. AREAS COVERED This review discusses the current understanding of LXR biology with an emphasis on the molecular aspects of LXR signalling establishing their potential as drug targets. Recent advances of their transcriptional mechanisms in inflammatory pathways and their physiological roles in inflammation and immunity are described. EXPERT OPINION The new discoveries of LXR-regulated inflammatory pathways have ignited new promises for LXRs as drug targets. The broad physiological roles of LXRs involve a high risk of unwanted side effects. Recent insights into LXR biology of the brain indicate a highly important role in neuronal development and a clinical trial testing an LXR agonist reported adverse neurological side effects. This suggests that drug development must focus on limiting the range of LXR signalling - possibly achieved through subtype, tissue specific, promoter specific or pathway specific activation of LXRs where a successful candidate drug must be carefully studied for its effect in the central nervous system.
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Affiliation(s)
- Knut R Steffensen
- Karolinska Institutet, Center for Biosciences, Department of Biosciences and Nutrition, S-14183 Stockholm, Sweden.
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37
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Zhong D, Huang G, Zhang Y, Zeng Y, Xu Z, Zhao Y, He X, He F. MicroRNA-1 and microRNA-206 suppress LXRα-induced lipogenesis in hepatocytes. Cell Signal 2013; 25:1429-37. [PMID: 23499676 DOI: 10.1016/j.cellsig.2013.03.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/19/2013] [Accepted: 03/06/2013] [Indexed: 01/14/2023]
Abstract
Liver X receptor α (LXRα) plays a critical role in the transcriptional control of lipid metabolism. LXR activation induces the expression of lipogenic genes, which promote hepatic steatosis and steatohepatitis. However, the regulation of LXR is not fully understood. MicroRNAs (miRs) are regarded as important negative regulators of gene expression. In this study, we found that miR-1/miR-206 repressed LXRα-induced accumulation of lipid droplets in hepatocytes. In addition, bioinformatic analysis predicted a same putative target-site for miR-1/miR-206 located within the 3'-untranslated region (3'-UTR) of LXRα mRNA. The reporter assay revealed that miR-1/miR-206 directly targeted the 3'-UTR of LXRα mRNA. Furthermore, miR-1/miR-206 repressed LXRα expression at both mRNA and protein levels, accompanied with the inhibition of expression of LXRα target genes, such as sterol-regulatory element binding protein 1c, fatty acid synthase, carbohydrate responsive element-binding protein and acetyl-CoA carboxylase 1, which are important effectors of LXRα implicated in lipogenesis. Moreover, ectopic expression of LXRα without the 3'-UTR dramatically attenuated the miR-1/miR-206-induced decrease of lipogenic genes and lipid droplet accumulation. Taken together, we for the first time demonstrated that miR-1/miR-206 attenuated LXRα-induced lipogenesis by targeting the 3'-UTR of LXRα mRNA, suggesting that miR-1/miR-206-LXRα pathway may be a novel target for the treatment of lipogenesis-associated diseases.
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Affiliation(s)
- Dan Zhong
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
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38
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Zhong D, Zhang Y, Zeng YJ, Gao M, Wu GZ, Hu CJ, Huang G, He FT. MicroRNA-613 represses lipogenesis in HepG2 cells by downregulating LXRα. Lipids Health Dis 2013; 12:32. [PMID: 23496987 PMCID: PMC3605323 DOI: 10.1186/1476-511x-12-32] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 02/28/2013] [Indexed: 12/22/2022] Open
Abstract
Background MicroRNAs (miRNAs) emerge as new important regulators of lipid homeostasis by regulating corresponding genes. MiR-613 is a newly discovered microRNA, of which the biological function is unknown. A recent report has shown that miR-613 downregulates liver X receptor α (LXRα), a ligand-activated nuclear receptor playing an important role in the regulation of lipid metabolism. The purpose of this study is to explore the effect and the molecular basis of miR-613 on lipogenesis in HepG2 cells. Methods HepG2 cells were transiently transfected with miR-613 mimic or control microRNA. Real time PCR, Western blot, Luciferase reporter assay and Oil Red O staining were employed to examine the expression of LXRα and its target genes involved in lipogenesis, binding site for miR-613 in 3′-untranslated region (3′-UTR) of LXRα mRNA and lipid droplet accumulation in the cells. Results MiR-613 dramatically suppressed the expression of LXRα and its target genes including sterol-regulatory element binding protein 1c (SREBP-1c), fatty acid synthase (FAS), carbohydrate responsive element-binding protein (ChREBP) and acetyl-CoA carboxylase (ACC). Reporter assay showed that miR-613 directly bound to 3′-UTR of LXRα mRNA. Moreover, miR-613 significantly repressed LXRα-induced lipid droplet accumulation in HepG2 cells. Ectopic expression of LXRα without 3′-UTR markedly attenuated the miR-613-mediated downregulation of LXRα’s target genes and LXRα-induced lipid droplet accumulation. Conclusions MiR-613 suppresses lipogenesis by directly targeting LXRα in HepG2 cells, suggesting that miR-613 may serve as a novel target for regulating lipid homeostasis.
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Affiliation(s)
- Dan Zhong
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
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39
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Abstract
Liver X receptors (LXRs) belong to the nuclear receptor superfamily of ligand-dependent transcription factors. LXRs are activated by oxysterols, metabolites of cholesterol, and therefore act as intracellular sensors of this lipid. There are two LXR genes (α and β) that display distinct tissue/cell expression profiles. LXRs interact with regulatory sequences in target genes as heterodimers with retinoid X receptor. Such direct targets of LXR actions include important genes implicated in the control of lipid homeostasis, particularly reverse cholesterol transport. In addition, LXRs attenuate the transcription of genes associated with the inflammatory response indirectly by transrepression. In this review, we describe recent evidence that both highlights the key roles of LXRs in atherosclerosis and inflammation and provides novel insights into the mechanisms underlying their actions. In addition, we discuss the major limitations of LXRs as therapeutic targets for the treatment of atherosclerosis and how these are being addressed.
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40
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Alba G, Reyes ME, Santa-María C, Ramírez R, Geniz I, Jiménez J, Martín-Nieto J, Pintado E, Sobrino F. Transcription of liver X receptor is down-regulated by 15-deoxy-Δ(12,14)-prostaglandin J(2) through oxidative stress in human neutrophils. PLoS One 2012; 7:e42195. [PMID: 23115616 PMCID: PMC3480349 DOI: 10.1371/journal.pone.0042195] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 07/04/2012] [Indexed: 01/04/2023] Open
Abstract
Liver X receptors (LXRs) are ligand-activated transcription factors of the nuclear receptor superfamily. They play important roles in controlling cholesterol homeostasis and as regulators of inflammatory gene expression and innate immunity, by blunting the induction of classical pro-inflammatory genes. However, opposite data have also been reported on the consequences of LXR activation by oxysterols, resulting in the specific production of potent pro-inflammatory cytokines and reactive oxygen species (ROS). The effect of the inflammatory state on the expression of LXRs has not been studied in human cells, and constitutes the main aim of the present work. Our data show that when human neutrophils are triggered with synthetic ligands, the synthesis of LXRα mRNA became activated together with transcription of the LXR target genes ABCA1, ABCG1 and SREBP1c. An inflammatory mediator, 15-deoxy-Δ12,14-prostaglandin J2 (15dPGJ2), hindered T0901317-promoted induction of LXRα mRNA expression together with transcription of its target genes in both neutrophils and human macrophages. This down-regulatory effect was dependent on the release of reactive oxygen species elicited by 15dPGJ2, since it was enhanced by pro-oxidant treatment and reversed by antioxidants, and was also mediated by ERK1/2 activation. Present data also support that the 15dPGJ2-induced serine phosphorylation of the LXRα molecule is mediated by ERK1/2. These results allow to postulate that down-regulation of LXR cellular levels by pro-inflammatory stimuli might be involved in the development of different vascular diseases, such as atherosclerosis.
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Affiliation(s)
- Gonzalo Alba
- Departamento de Bioquímica Médica y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - María Edith Reyes
- Departamento de Bioquímica Médica y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - Consuelo Santa-María
- Departamento de Bioquímica y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - Remedios Ramírez
- Departamento de Bioquímica Médica y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - Isabel Geniz
- Distrito Sanitario Sevilla Norte, Servicio Andaluz de Salud, Sevilla, Spain
| | - Juan Jiménez
- Departamento de Bioquímica Médica y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - José Martín-Nieto
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Elízabeth Pintado
- Departamento de Bioquímica Médica y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - Francisco Sobrino
- Departamento de Bioquímica Médica y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
- * E-mail:
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41
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González-Granillo M, Steffensen KR, Granados O, Torres N, Korach-André M, Ortíz V, Aguilar-Salinas C, Jakobsson T, Díaz-Villaseñor A, Loza-Valdes A, Hernandez-Pando R, Gustafsson JÅ, Tovar AR. Soy protein isoflavones differentially regulate liver X receptor isoforms to modulate lipid metabolism and cholesterol transport in the liver and intestine in mice. Diabetologia 2012; 55:2469-78. [PMID: 22739758 DOI: 10.1007/s00125-012-2599-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 04/30/2012] [Indexed: 01/18/2023]
Abstract
AIMS/HYPOTHESIS Liver X receptor (LXR)α regulates the genes involved in cholesterol, fatty acid and glucose metabolism. Soy protein (SP) consumption reduces the hepatic accumulation of cholesterol and triacylglycerol, and improves insulin sensitivity. However, it is not known whether these effects are mediated via LXRα. We therefore investigated whether the consumption of SP regulates metabolic changes in cholesterol metabolism and insulin sensitivity via LXRα. METHODS Wild-type (WT) and Lxrα(-/-) (Lxrα, also known as Nr1h3) mice were fed an SP diet with or without cholesterol for 28 days. The expression of LXRα target genes was measured in liver and intestine, as were hepatic lipid content and faecal bile acid concentration. Oral glucose and insulin tolerance tests were also performed. Hepatocytes were used to study the effect of isoflavones on LXR activity. RESULTS The livers of WT and Lxrα(-/-) mice fed an SP high-cholesterol diet showed less steatosis than those fed casein. The SP diet increased the expression of the ATP-binding cassette (ABC) sub-family genes Abca1, Abcg5 and Abcg8 in the liver and intestine, as well as increasing total faecal bile acid excretion and insulin sensitivity in WT mice compared with mice fed a casein diet. However, these effects of SP were not observed in Lxrα(-/-) mice. The SP isoflavone, genistein, repressed the activation of LXRα target genes by T0901317, whereas it stimulated the activation of LXRβ target genes. The AMP-activated protein kinase inhibitor, compound C, had the opposite effects to those of genistein. CONCLUSIONS/INTERPRETATION Our results suggest that SP isoflavones stimulate the phosphorylation of LXRα or LXRβ, resulting in different biological effects for each LXR isoform.
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Affiliation(s)
- M González-Granillo
- Departamento Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición, Vasco de Quiroga No 15, Tlalpan, México DF 14000, México
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42
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Biological Roles of Liver X Receptors in Immune Cells. Arch Immunol Ther Exp (Warsz) 2012; 60:235-49. [DOI: 10.1007/s00005-012-0179-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 03/16/2012] [Indexed: 12/17/2022]
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43
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Jakobsson T, Treuter E, Gustafsson JÅ, Steffensen KR. Liver X receptor biology and pharmacology: new pathways, challenges and opportunities. Trends Pharmacol Sci 2012; 33:394-404. [PMID: 22541735 DOI: 10.1016/j.tips.2012.03.013] [Citation(s) in RCA: 240] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/05/2012] [Accepted: 03/26/2012] [Indexed: 01/12/2023]
Abstract
Nuclear receptors (NRs) are master regulators of transcriptional programs that integrate the homeostatic control of almost all biological processes. Their direct mode of ligand regulation and genome interaction is at the core of modern pharmacology. The two liver X receptors LXRα and LXRβ are among the emerging newer drug targets within the NR family. LXRs are best known as nuclear oxysterol receptors and physiological regulators of lipid and cholesterol metabolism that also act in an anti-inflammatory way. Because LXRs control diverse pathways in development, reproduction, metabolism, immunity and inflammation, they have potential as therapeutic targets for diseases as diverse as lipid disorders, atherosclerosis, chronic inflammation, autoimmunity, cancer and neurodegenerative diseases. Recent insights into LXR signaling suggest future targeting strategies aiming at increasing LXR subtype and pathway selectivity. This review discusses the current status of our understanding of LXR biology and pharmacology, with an emphasis on the molecular aspects of LXR signaling that constitute the potential of LXRs as drug targets.
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Affiliation(s)
- Tomas Jakobsson
- Center for Biosciences, Department of Biosciences and Nutrition, Karolinska Institutet, S-14183 Stockholm, Sweden
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Na TY, Lee HJ, Oh HJ, Huh S, Lee IK, Lee MO. Positive Cross-Talk Between Hypoxia Inducible Factor-1α and Liver X Receptor α Induces Formation of Triglyceride-Loaded Foam Cells. Arterioscler Thromb Vasc Biol 2011; 31:2949-56. [DOI: 10.1161/atvbaha.111.235788] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Atherosclerosis is a chronic and progressive inflammatory disease of the arteries that is characterized by subendothelial accumulation of lipid-rich macrophages, called foam cells. We sought to identify the molecular details of cross-talk between liver X receptor α (LXRα) and hypoxia-inducible factor 1α (HIF-1α) for the formation of triglyceride-rich foam cells under hypoxic conditions.
Methods and Results—
We first observed that expression of LXRα and its target lipogenic genes was time-dependently induced in human primary macrophages and RAW 264.7 cells under hypoxia. Similarly, TO901317, an activator of LXRα, enhanced the expression level and the transcriptional activity of HIF-1α. Second, we demonstrated that LXRα increased HIF-1α protein stability through a physical interaction between the ligand binding domain of LXRα and the oxygen-dependent degradation domain of HIF-1α. Third, we found that the activation of HIF-1α or LXRα synergistically induced triglyceride accumulation in macrophages. Finally, we showed that LXRα and HIF-1α were codistributed in the macrophages of atherosclerotic lesions of patients.
Conclusion—
These results suggest that the positive feed-forward regulation of transcriptional activity and protein stability of LXRα and HIF-1α has an important impact in foam cell formation.
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Affiliation(s)
- Tae-Young Na
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Hyo-Jeong Lee
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Hyeon-Jeong Oh
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Seung Huh
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - In-Kyu Lee
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Mi-Ock Lee
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
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45
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Computational and experimental studies of the interaction between phospho-peptides and the C-terminal domain of BRCA1. J Comput Aided Mol Des 2011; 25:1071-84. [PMID: 22086652 DOI: 10.1007/s10822-011-9484-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 11/02/2011] [Indexed: 10/15/2022]
Abstract
The C-terminal domain of BRCA1(BRCT) is involved in the DNA repair pathway by recognizing the pSXXF motif in interacting proteins. It has been reported that short peptides containing this motif bind to BRCA1(BRCT) in the micromolar range with high specificity. In this work, the binding of pSXXF peptides has been studied computationally and experimentally in order to characterize their interaction with BRCA1(BRCT). Elucidation of the contacts that drive the protein-ligand interaction is critical for the development of high affinity small-molecule BRCA1 inhibitors. Molecular dynamics (MD) simulations revealed the key role of threonine at the peptide P+2 position in providing structural rigidity to the ligand in the bound state. The mutation at P+1 had minor effects. Peptide extension at the N-terminal position with the naphthyl amino acid exhibited a modest increase in binding affinity, what could be explained by the dispersion interaction of the naphthyl side-chain with a hydrophobic patch. Three in silico end-point methods were considered for the calculation of binding free energy. The Molecular Mechanics Poisson-Boltzmann Surface Area and the Solvated Interaction Energy methods gave reasonable agreement with experimental data, exhibiting a Pearlman predictive index of 0.71 and 0.78, respectively. The MM-quantum mechanics-surface area method yielded improved results, which was characterized by a Pearlman index of 0.78. The correlation coefficients were 0.59, 0.61 and 0.69, respectively. The ability to apply a QM level of theory within an end-point binding free energy protocol may provide a way for a consistent improvement of accuracy in computer-aided drug design.
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46
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Pourcet B, Feig JE, Vengrenyuk Y, Hobbs AJ, Kepka-Lenhart D, Garabedian MJ, Morris SM, Fisher EA, Pineda-Torra I. LXRα regulates macrophage arginase 1 through PU.1 and interferon regulatory factor 8. Circ Res 2011; 109:492-501. [PMID: 21757649 DOI: 10.1161/circresaha.111.241810] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RATIONALE Activation of liver X receptors (LXRs) inhibits the progression of atherosclerosis and promotes regression of existing lesions. In addition, LXRα levels are high in regressive plaques. Macrophage arginase 1 (Arg1) expression is inversely correlated with atherosclerosis progression and is markedly decreased in foam cells within the lesion. OBJECTIVE To investigate LXRα regulation of Arg1 expression in cultured macrophages and atherosclerotic regressive lesions. METHODS AND RESULTS We found that Arg1 expression is enhanced in CD68+ cells from regressive versus progressive lesions in a murine aortic arch transplant model. In cultured macrophages, ligand-activated LXRα markedly enhances basal and interleukin-4-induced Arg1 mRNA and protein expression as well as promoter activity. This LXRα-enhanced Arg1 expression correlates with a reduction in nitric oxide levels. Moreover, Arg1 expression within regressive atherosclerotic plaques is LXRα-dependent, as enhanced expression of Arg1 in regressive lesions is impaired in LXRα-deficient CD68+ cells. LXRα does not bind to the Arg1 promoter but instead promotes the interaction between PU.1 and interferon regulatory factor (IRF)8 transcription factors and induces their binding of a novel composite element. Accordingly, knockdown of either IRF8 or PU.1 strongly impairs LXRα regulation of Arg1 expression in macrophage cells. Finally, we demonstrate that LXRα binds the IRF8 locus and its activation increases IRF8 mRNA and protein levels in these cells. CONCLUSIONS This work implicates Arg1 in atherosclerosis regression and identifies LXRα as a novel regulator of Arg1 and IRF8 in macrophages. Furthermore, it provides a unique molecular mechanism by which LXRα regulates macrophage target gene expression through PU.1 and IRF8.
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Affiliation(s)
- Benoit Pourcet
- Centre for Clinical Pharmacology, Division of Medicine, University College London, London, United Kingdom
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47
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Berrabah W, Aumercier P, Lefebvre P, Staels B. Control of nuclear receptor activities in metabolism by post-translational modifications. FEBS Lett 2011; 585:1640-50. [PMID: 21486568 DOI: 10.1016/j.febslet.2011.03.066] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 03/30/2011] [Indexed: 12/24/2022]
Abstract
Nuclear receptors (NRs) are molecular transducers of endocrine and dietary signals allowing tissues to adapt their transcriptional responses to endogenous or exogenous cues. These signals act in many cases as specific ligands, converting of NRs into transcriptionally active molecules. This on-off mechanism needs, however, to be finely tuned with respect to the tissue environment and adjusted to the organism needs. These subtle adjustments of NR transcriptional activity are brought about by post-translational modifications (PTMs), which can be, in the case of orphan NRs, the sole regulatory mechanism. The role of PTMs, with a more specific focus on phosphorylation, affecting the functions of NR controlling metabolic events is described in this review.
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Affiliation(s)
- Wahiba Berrabah
- Université Lille Nord de France, INSERM, U1011, Lille, France
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48
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Huwait EA, Greenow KR, Singh NN, Ramji DP. A novel role for c-Jun N-terminal kinase and phosphoinositide 3-kinase in the liver X receptor-mediated induction of macrophage gene expression. Cell Signal 2011; 23:542-9. [PMID: 21070853 PMCID: PMC3126994 DOI: 10.1016/j.cellsig.2010.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 10/29/2010] [Accepted: 11/03/2010] [Indexed: 11/01/2022]
Abstract
Liver X receptors (LXRs) are ligand-dependent transcription factors that are activated by metabolites of cholesterol, oxysterols, and a number of synthetic agonists. LXRs play potent anti-atherogenic roles in part by stimulating the efflux of cholesterol from macrophage foam cells. The LXR-induced expression of ATP-binding cassette transporter (ABC)-A1 and Apolipoprotein E (ApoE) in macrophages is essential for the stimulation of cholesterol efflux and the prevention of atherosclerotic development. Unfortunately, the signaling pathways underlying such regulation are poorly understood and were therefore investigated in human macrophages. The expression of ApoE and ABCA1 induced by synthetic or natural LXR ligands [TO901317, GW3965, and 22-(R)-hydroxycholesterol (22-(R)-HC), respectively] was attenuated by inhibitors of c-Jun N-terminal kinase (JNK) (curcumin and SP600125) and phosphoinositide 3-kinase (PI3K) (LY294002). Similar results were obtained with ABCG1 and LXR-α, two other LXR target genes. LXR agonists activated several components of the JNK pathway (SEK1, JNK and c-Jun) along with AKT, a downstream target for PI3K. In addition, dominant negative mutants of JNK and PI3K pathways inhibited the LXR-agonists-induced activity of the ABCA1 and LXR-α gene promoters in transfected cells. LXR agonists also induced the binding of activator protein-1 (AP-1), a key transcription factor family regulated by JNK, to recognition sequences present in the regulatory regions of the ApoE and ABCA1 genes. These studies reveal a novel role for JNK and PI3K/AKT signaling in the LXR-regulated expression in macrophages of several key genes implicated in atherosclerosis.
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Affiliation(s)
| | | | - Nishi N. Singh
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Dipak P. Ramji
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
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49
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Han CY, Ki SH, Kim YW, Noh K, Lee DY, Kang B, Ryu JH, Jeon R, Kim EH, Hwang SJ, Kim SG. Ajoene, a stable garlic by-product, inhibits high fat diet-induced hepatic steatosis and oxidative injury through LKB1-dependent AMPK activation. Antioxid Redox Signal 2011; 14:187-202. [PMID: 20560786 DOI: 10.1089/ars.2010.3190] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hepatic steatosis, a hepatic component of metabolic syndrome, is common and may progress to steatohepatitis and cirrhosis. The liver X receptor-α (LXRα)-sterol regulatory element binding protein-1c (SREBP-1c) pathway plays a key role in hepatic steatosis. This study investigated the potential of ajoene, a stable garlic by-product, to inhibit high fat diet (HFD)-induced hepatic steatosis and the underlying mechanism. Ajoene treatment attenuated fat accumulation and induction of lipogenic genes in the liver of HFD-fed mice. Blood biochemical analyses and histopathologic examinations showed that ajoene prevented liver injury with the inhibition of oxidative stress, as evidenced by thiobarbituric acid reactive substances formation and nitrotyrosinylation. Moreover, ajoene treatment inhibited LXRα agonist (T0901317)-mediated SREBP-1c activation, and transactivation of the lipogenic target genes in hepatocytes. Ajoene was found to activate AMP-activated protein kinase (AMPK) via LKB1, responsible for the inhibition of p70 ribosomal S6 kinase-1 (S6K1). The ability of ajoene to repress T0901317-induced SREBP-1c expression was antagonized by inhibition of AMPK or activation of S6K1, supporting the role of these kinases in the antisteatotic effect. Our results demonstrate that ajoene has an effect of activating AMPK through LKB1 and inhibit S6K1 activity, contributing to the prevention of SREBP-1c-mediated hepatic lipogenesis via the inhibition of LXRα activity.
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Affiliation(s)
- Chang Yeob Han
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
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50
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A-González N, Castrillo A. Liver X receptors as regulators of macrophage inflammatory and metabolic pathways. Biochim Biophys Acta Mol Basis Dis 2010; 1812:982-94. [PMID: 21193033 DOI: 10.1016/j.bbadis.2010.12.015] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/14/2010] [Accepted: 12/17/2010] [Indexed: 12/30/2022]
Abstract
The liver X receptors (LXRα and LXRβ) are members of the nuclear receptor family of transcription factors that play essential roles in the transcriptional control of lipid metabolism. LXRs are endogenously activated by modified forms of cholesterol known as oxysterols and control the expression of genes important for cholesterol uptake, efflux, transport, and excretion in multiple tissues. In addition to their role as cholesterol sensors, a number of studies have implicated LXRs in the modulation of innate and adaptive immune responses. Both through activation and repression mechanisms, LXRs regulate diverse aspects of inflammatory gene expression in macrophages. The ability of LXRs to coordinate metabolic and immune responses constitutes an attractive therapeutic target for the treatment of chronic inflammatory disorders. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.
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Affiliation(s)
- Noelia A-González
- Department of Biochemistry and Molecular Biology, Universidad de Las Palmas de Gran Canaria, ULPGC, Las Palmas, Spain
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