51
|
ROR nuclear receptors: structures, related diseases, and drug discovery. Acta Pharmacol Sin 2015; 36:71-87. [PMID: 25500868 DOI: 10.1038/aps.2014.120] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 10/08/2014] [Indexed: 12/31/2022] Open
Abstract
Nuclear receptors (NRs) are ligand-regulated transcription factors that regulate metabolism, development and immunity. The NR superfamily is one of the major classes of drug targets for human diseases. Retinoic acid receptor-related orphan receptor (ROR) α, β and γ belong to the NR superfamily, and these receptors are still considered as 'orphan' receptors because the identification of their endogenous ligands has been controversial. Recent studies have demonstrated that these receptors are regulated by synthetic ligands, thus emerge as important drug targets for the treatment of multiple sclerosis, rheumatoid arthritis, psoriasis, etc. Studying the structural basis and ligand development of RORs will pave the way for a better understanding of the roles of these receptors in human diseases. Here, we review the structural basis, disease relevance, strategies for ligand identification, and current status of development of therapeutic ligands for RORs.
Collapse
|
52
|
Adamovich Y, Aviram R, Asher G. The emerging roles of lipids in circadian control. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:1017-25. [PMID: 25483623 DOI: 10.1016/j.bbalip.2014.11.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 11/16/2014] [Accepted: 11/24/2014] [Indexed: 12/20/2022]
Abstract
Lipids play vital roles in a wide variety of cellular functions. They act as structural components in cell membranes, serve as a major form of energy storage, and function as key signaling molecules. Mounting evidence points towards a tight interplay between lipids and circadian clocks. In mammals, circadian clocks regulate the daily physiology and metabolism, and disruption of circadian rhythmicity is associated with altered lipid homeostasis and pathologies such as fatty liver and obesity. Concomitantly, emerging evidence suggest that lipids are embedded within the core clock circuitry and participate in circadian control. Recent advances in lipidomics methodologies and their application in chronobiology studies have shed new light on the cross talk between circadian clocks and lipid homeostasis. We review herein the latest literature related to the involvement of lipids in circadian clock's function and highlight the contribution of circadian lipidomics studies to our understanding of circadian rhythmicity and lipid homeostasis. This article is part of a Special Issue entitled Brain Lipids.
Collapse
Affiliation(s)
- Yaarit Adamovich
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rona Aviram
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gad Asher
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
| |
Collapse
|
53
|
Mazzoccoli G, Vinciguerra M, Oben J, Tarquini R, De Cosmo S. Non-alcoholic fatty liver disease: the role of nuclear receptors and circadian rhythmicity. Liver Int 2014; 34:1133-52. [PMID: 24649929 DOI: 10.1111/liv.12534] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 03/16/2014] [Indexed: 12/22/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the accumulation of triglycerides in the hepatocytes in the absence of excess alcohol intake, and is caused by an imbalance between hepatic synthesis and breakdown of fats, as well as fatty acid storage and disposal. Liver metabolic pathways are driven by circadian biological clocks, and hepatic health is maintained by proper timing of circadian patterns of metabolic gene expression with the alternation of anabolic processes corresponding to feeding/activity during wake times, and catabolic processes characterizing fasting/resting during sleep. A number of nuclear receptors in the liver are expressed rhythmically, bind hormones and metabolites, sense energy flux and expenditure, and connect the metabolic pathways to the molecular clockwork throughout the 24-h day. In this review, we describe the role played by the nuclear receptors in the genesis of NAFLD in relationship with the circadian clock circuitry.
Collapse
Affiliation(s)
- Gianluigi Mazzoccoli
- Division of Internal Medicine and Chronobiology Unit, Department of Medical Sciences, IRCCS Scientific Institute and Regional General Hospital "Casa Sollievo della Sofferenza", San Giovanni Rotondo (FG), Italy
| | | | | | | | | |
Collapse
|
54
|
Kim EJ, Choi YK, Han YH, Kim HJ, Lee IK, Lee MO. RORα suppresses proliferation of vascular smooth muscle cells through activation of AMP-activated protein kinase. Int J Cardiol 2014; 175:515-21. [DOI: 10.1016/j.ijcard.2014.06.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 05/05/2014] [Accepted: 06/24/2014] [Indexed: 12/20/2022]
|
55
|
Sancar G, Brunner M. Circadian clocks and energy metabolism. Cell Mol Life Sci 2014; 71:2667-80. [PMID: 24515123 PMCID: PMC11113245 DOI: 10.1007/s00018-014-1574-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 01/08/2014] [Accepted: 01/23/2014] [Indexed: 12/25/2022]
Abstract
Circadian clocks orchestrate behavioral and physiological processes in a time-of-day dependent manner. The network of clock-controlled genes is intimately interconnected with metabolic regulatory circuits. Circadian clocks rhythmically regulate the expression and activity of key metabolic players, which in turn feed back on the circadian machinery on the transcriptional and post-transcriptional level. Mutations of clock genes are often associated with metabolic defects, especially in lipid and glucose metabolism. Accumulating data suggest that the reciprocal coordination of circadian and metabolic pathways is crucial for cellular homeostasis and the health of the organism.
Collapse
Affiliation(s)
- Gencer Sancar
- University of Heidelberg Biochemistry Center, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany,
| | | |
Collapse
|
56
|
Yuan Y, Hou X, Zhang J, Chen Y, Feng Y, Su Z. Genetic variations in RORα are associated with chronic obstructive pulmonary disease. J Hum Genet 2014; 59:430-6. [PMID: 24943193 DOI: 10.1038/jhg.2014.48] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 05/14/2014] [Accepted: 05/21/2014] [Indexed: 02/05/2023]
Abstract
Retinoic acid receptor-related orphan receptor-α (RORα) plays a key role in the regulation of lipid and cholesterol metabolism that has been implicated in the development of chronic obstructive pulmonary disease (COPD). The aim of this study was to determine the frequencies of single-nucleotide polymorphisms (SNPs) in RORα gene in a Chinese population and their possible association with COPD susceptibility. Nine tagging SNPs, including rs17270181, rs1898413, rs17270216, rs8033552, rs8036966, rs7169364, rs340002, rs340023 and rs11630262, were screened in 279 COPD patients and 367 controls by the SNaPshot method. Association analysis of genotypes and haplotypes constructed from these loci with COPD was conducted under different genetic models. Alleles or genotypes of rs8033552 distributed significantly differently in COPD patients and controls (allele: P=0.0001, false discovery rate (FDR) Q=0.004, odds ratios (OR): 1.62 and 95% confidence interval (CI): 1.27-2.07; genotype: P=0.0005, FDR Q=0.008). The allele A at rs8033552 was potentially associated with an increased risk of COPD in additive model, displaying ORs of 1.62 (95% CI: 1.17-2.26, P=0.004, FDR Q=0.019) in subjects with genotypes AG vs GG and 2.69 (95% CI: 1.47-4.93, P=0.001, FDR Q=0.011) in subjects with genotypes AA vs GG, respectively. In haplotype analysis, we observed haplotypes GGAGATGTG and GGAGCTGTG had protective effects, whereas haplotypes GGAGATACA and GGAGATACG were significantly associated with the increased risk of COPD. These data suggest that RORα may be a potential risk gene for COPD.
Collapse
Affiliation(s)
- Yiming Yuan
- Department of Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoming Hou
- Molecular Medicine Research Center, West China Hospital, and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Jinlong Zhang
- Molecular Medicine Research Center, West China Hospital, and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Yulong Chen
- Molecular Medicine Research Center, West China Hospital, and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Yulin Feng
- Department of Respiratory Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Zhiguang Su
- Molecular Medicine Research Center, West China Hospital, and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| |
Collapse
|
57
|
Kuivenhoven JA, Hegele RA. Mining the genome for lipid genes. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1993-2009. [PMID: 24798233 DOI: 10.1016/j.bbadis.2014.04.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/22/2014] [Accepted: 04/27/2014] [Indexed: 12/12/2022]
Abstract
Mining of the genome for lipid genes has since the early 1970s helped to shape our understanding of how triglycerides are packaged (in chylomicrons), repackaged (in very low density lipoproteins; VLDL), and hydrolyzed, and also how remnant and low-density lipoproteins (LDL) are cleared from the circulation. Gene discoveries have also provided insights into high-density lipoprotein (HDL) biogenesis and remodeling. Interestingly, at least half of these key molecular genetic studies were initiated with the benefit of prior knowledge of relevant proteins. In addition, multiple important findings originated from studies in mouse, and from other types of non-genetic approaches. Although it appears by now that the main lipid pathways have been uncovered, and that only modulators or adaptor proteins such as those encoded by LDLRAP1, APOA5, ANGPLT3/4, and PCSK9 are currently being discovered, genome wide association studies (GWAS) in particular have implicated many new loci based on statistical analyses; these may prove to have equally large impacts on lipoprotein traits as gene products that are already known. On the other hand, since 2004 - and particularly since 2010 when massively parallel sequencing has become de rigeur - no major new insights into genes governing lipid metabolism have been reported. This is probably because the etiologies of true Mendelian lipid disorders with overt clinical complications have been largely resolved. In the meantime, it has become clear that proving the importance of new candidate genes is challenging. This could be due to very low frequencies of large impact variants in the population. It must further be emphasized that functional genetic studies, while necessary, are often difficult to accomplish, making it hazardous to upgrade a variant that is simply associated to being definitively causative. Also, it is clear that applying a monogenic approach to dissect complex lipid traits that are mostly of polygenic origin is the wrong way to proceed. The hope is that large-scale data acquisition combined with sophisticated computerized analyses will help to prioritize and select the most promising candidate genes for future research. We suggest that at this point in time, investment in sequence technology driven candidate gene discovery could be recalibrated by refocusing efforts on direct functional analysis of the genes that have already been discovered. This article is part of a Special Issue entitled: From Genome to Function.
Collapse
Affiliation(s)
- Jan Albert Kuivenhoven
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Section Molecular Genetics, Antonius Deusinglaan 1, 9713GZ Groningen, The Netherlands
| | - Robert A Hegele
- Blackburn Cardiovascular Genetics Laboratory, Robarts Research Institute, 4288A-1151 Richmond Street North, London, ON N6A 5B7, Canada
| |
Collapse
|
58
|
Chang MR, Lyda B, Kamenecka TM, Griffin PR. Pharmacologic repression of retinoic acid receptor-related orphan nuclear receptor γ is therapeutic in the collagen-induced arthritis experimental model. Arthritis Rheumatol 2014; 66:579-88. [PMID: 24574218 DOI: 10.1002/art.38272] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 11/05/2013] [Indexed: 12/15/2022]
Abstract
OBJECTIVE The nuclear receptor retinoic acid receptor-related orphan nuclear receptor γ (RORγ; T cell-specific isoform RORγt) is a key regulator of Th17 cell differentiation, controlling the production of the inflammatory cytokine interleukin-17 (IL-17). Lipopolysaccharide (LPS) stimulation of monocytes leads to the induction of RORγ. We previously showed that the potent and selective inverse agonist of RORγ, SR2211, was effective at suppressing IL-17 production in EL4 cells. The aim of this study was to examine the effects of SR2211 treatment on proinflammatory cytokine expression in LPS-stimulated RAW 264.7 cells as well as on joint inflammation in vivo in mice with collagen-induced arthritis (CIA). METHODS Collagen was injected into the tail of DBA mice, followed by a booster inoculation 21 days later. Three days prior to the booster inoculation, SR2211 was administered twice daily for 15 days. Thymus, spleen, and draining lymph nodes (DLNs) were then harvested, and Th17 cell differentiation and DLN stimulation were performed. RESULTS Treatment of Th17 cells with SR2211 suppressed the expression and production of inflammatory cytokines. Likewise, SR2211 reduced inflammatory cytokine production in LPS-stimulated RAW 264.7 cells. Mice with CIA that received SR2211 twice daily for 15 days exhibited a statistically significant reduction in joint inflammation as compared to mice that received only vehicle. Interestingly, systemic Th1 cell activation was detected in SR2211-treated mice with CIA, as indicated by an increase in interferon-γ levels. CONCLUSION The findings of this study support the idea of targeting RORγ to therapeutically repress inflammatory T cell function and macrophage activation in humans with rheumatoid arthritis. Compounds such as SR2211 have potential utility for the treatment of inflammatory disease.
Collapse
Affiliation(s)
- Mi Ra Chang
- The Scripps Research Institute, Scripps Florida, Jupiter
| | | | | | | |
Collapse
|
59
|
Gooley JJ, Chua ECP. Diurnal regulation of lipid metabolism and applications of circadian lipidomics. J Genet Genomics 2014; 41:231-50. [PMID: 24894351 DOI: 10.1016/j.jgg.2014.04.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 04/10/2014] [Accepted: 04/10/2014] [Indexed: 02/04/2023]
Abstract
The circadian timing system plays a key role in orchestrating lipid metabolism. In concert with the solar cycle, the circadian system ensures that daily rhythms in lipid absorption, storage, and transport are temporally coordinated with rest-activity and feeding cycles. At the cellular level, genes involved in lipid synthesis and fatty acid oxidation are rhythmically activated and repressed by core clock proteins in a tissue-specific manner. Consequently, loss of clock gene function or misalignment of circadian rhythms with feeding cycles (e.g., in shift work) results in impaired lipid homeostasis. Herein, we review recent progress in circadian rhythms research using lipidomics, i.e., large-scale profiling of lipid metabolites, to characterize circadian-regulated lipid pathways in mammals. In mice, novel regulatory circuits involved in fatty acid metabolism have been identified in adipose tissue, liver, and muscle. Extensive diversity in circadian regulation of plasma lipids has also been revealed in humans using lipidomics and other metabolomics approaches. In future studies, lipidomics platforms will be increasingly used to better understand the effects of genetic variation, shift work, food intake, and drugs on circadian-regulated lipid pathways and metabolic health.
Collapse
Affiliation(s)
- Joshua J Gooley
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston 02115, USA; Division of Sleep Medicine, Harvard Medical School, Boston 02115, USA.
| | - Eric Chern-Pin Chua
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| |
Collapse
|
60
|
Kuang J, Hou X, Zhang J, Chen Y, Su Z. Identification of insulin as a novel retinoic acid receptor-related orphan receptor α target gene. FEBS Lett 2014; 588:1071-9. [PMID: 24583012 DOI: 10.1016/j.febslet.2014.02.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 01/27/2014] [Accepted: 02/14/2014] [Indexed: 02/05/2023]
Abstract
Insulin plays an important role in regulation of lipid and glucose metabolism. Retinoic acid receptor-related orphan receptor α (RORα) modulates physiopathological processes such as dyslipidemia and diabetes. In this study, we found overexpression of RORα in INS1 cells resulted in increased expression and secretion of insulin. Suppression of endogenous RORα caused a decrease of insulin expression. Luciferase and electrophoretic mobility shift assay (EMSA) assays demonstrated that RORα activated insulin transcription via direct binding to its promoter. RORα was also observed to regulate BETA2 expression, which is one of the insulin active transfactors. In vivo analyses showed that the insulin transcription is increased by the synthetic RORα agonist SR1078. These findings identify RORα as a transcriptional activator of insulin and suggest novel therapeutic opportunities for management of the disease.
Collapse
Affiliation(s)
- Jiangying Kuang
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoming Hou
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Jinlong Zhang
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Yulong Chen
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Zhiguang Su
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
| |
Collapse
|
61
|
Podkolodnaya OA. Molecular and genetic aspects of interactions of the circadian clock and the energy-producing substrate metabolism in mammals. RUSS J GENET+ 2014. [DOI: 10.1134/s1022795414020136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
62
|
Abstract
At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.
Collapse
Affiliation(s)
- Paul N Hopkins
- Cardiovascular Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.
| |
Collapse
|
63
|
Kurakula K, Hamers AAJ, de Waard V, de Vries CJM. Nuclear Receptors in atherosclerosis: a superfamily with many 'Goodfellas'. Mol Cell Endocrinol 2013; 368:71-84. [PMID: 22664910 DOI: 10.1016/j.mce.2012.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 05/23/2012] [Accepted: 05/25/2012] [Indexed: 01/07/2023]
Abstract
Nuclear Receptors form a superfamily of 48 transcription factors that exhibit a plethora of functions in steroid hormone signaling, regulation of metabolism, circadian rhythm and cellular differentiation. In this review, we describe our current knowledge on the role of Nuclear Receptors in atherosclerosis, which is a multifactorial disease of the vessel wall. Various cell types are involved in this chronic inflammatory pathology in which multiple cellular processes and numerous genes are dysregulated. Systemic risk factors for atherosclerosis are among others adverse blood lipid profiles, enhanced circulating cytokine levels, as well as increased blood pressure. Since many Nuclear Receptors modulate lipid profiles or regulate blood pressure they indirectly affect atherosclerosis. In the present review, we focus on the functional involvement of Nuclear Receptors within the atherosclerotic vessel wall, more specifically on their modulation of cellular functions in endothelial cells, smooth muscle cells and macrophages. Collectively, this overview shows that most of the Nuclear Receptors are athero-protective in atherosclerotic lesions.
Collapse
Affiliation(s)
- Kondababu Kurakula
- Department of Medical Biochemistry, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | | |
Collapse
|
64
|
Kamenecka TM, Lyda B, Chang MR, Griffin PR. Synthetic modulators of the retinoic acid receptor-related orphan receptors. MEDCHEMCOMM 2013. [DOI: 10.1039/c3md00005b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
65
|
Tuong ZK, Lau P, Yeo JC, Pearen MA, Wall AA, Stanley AC, Stow JL, Muscat GEO. Disruption of Rorα1 and cholesterol 25-hydroxylase expression attenuates phagocytosis in male Rorαsg/sg mice. Endocrinology 2013; 154:140-9. [PMID: 23239817 DOI: 10.1210/en.2012-1889] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We and others have previously demonstrated that congenital deficiency of the nuclear hormone receptor, Rorα1, in staggerer (sg/sg) mice results in resistance to diet-induced obesity and increased insulin sensitivity. Paradoxically, the sg/sg mice are susceptible to atherosclerosis and display impaired innate immunity, underscoring the regulatory links between metabolic disease, inflammation, and susceptibility to infection. Here, we present novel evidence that Rorα1 regulates innate immune function by demonstrating impaired phagocytosis in sg/sg mice. The early stages of Fc-γ receptor-mediated phagocytosis in lipopolysaccharide-activated sg/sg bone marrow-derived macrophages (BMMs) were significantly impaired compared with wild-type cells. Moreover, in sg/sg BMMs, the phagocytic cup membranes had reduced levels of cholesterol. Expression profiling revealed dysregulated expression of genes involved in inflammation and lipid metabolism in sg/sg BMMs. Notably, we identified decreased expression of the mRNA encoding cholesterol 25-hydroxylase (Ch25h), an enzyme that converts cholesterol to 25-hydroxycholesterol (25HC), an oxysterol with emerging roles in immunity. Treatment of sg/sg BMMs with 25HC rescued phagocytosis in a dose-dependent manner, whereas small interfering RNA knockdown of Ch25h mRNA expression in wild-type cells attenuated phagocytosis. Hence, we propose that 25HC is essential for optimizing membrane internalization during phagocytosis and that aberrant Ch25h expression in Rorα1-deficient sg/sg macrophages disrupts phagocytosis. Our studies reveal new roles for Rorα1, Ch25h, and 25HC in phagocytosis. Aberrant 25HC underpins the paradoxical association between insulin sensitivity and impaired innate immunity in Rorα1-deficient mice, heralding a wider and essential role for this oxysterol at the nexus of metabolism and immunity.
Collapse
MESH Headings
- Animals
- Cells, Cultured
- Hydroxycholesterols/pharmacology
- Immunity, Innate/genetics
- Immunity, Innate/physiology
- Lipopolysaccharides/pharmacology
- Male
- Mice
- Nuclear Receptor Subfamily 1, Group F, Member 1/genetics
- Nuclear Receptor Subfamily 1, Group F, Member 1/metabolism
- Phagocytosis/genetics
- Phagocytosis/physiology
- Polymerase Chain Reaction
- RNA, Small Interfering/genetics
- Receptors, IgG/genetics
- Receptors, IgG/metabolism
- Steroid Hydroxylases/genetics
- Steroid Hydroxylases/metabolism
Collapse
Affiliation(s)
- Zewen K Tuong
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland 4072, Australia
| | | | | | | | | | | | | | | |
Collapse
|
66
|
Ou Z, Shi X, Gilroy RK, Kirisci L, Romkes M, Lynch C, Wang H, Xu M, Jiang M, Ren S, Gramignoli R, Strom SC, Huang M, Xie W. Regulation of the human hydroxysteroid sulfotransferase (SULT2A1) by RORα and RORγ and its potential relevance to human liver diseases. Mol Endocrinol 2013; 27:106-15. [PMID: 23211525 PMCID: PMC3545217 DOI: 10.1210/me.2012-1145] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 10/18/2012] [Indexed: 01/01/2023] Open
Abstract
The retinoid-related orphan receptors (RORs) were postulated to have functions in tissue development and circadian rhythm. In this study, we revealed a novel function of RORα (NR1F1) and RORγ (NR1F3) in regulating the human hydroxysteroid sulfotransferase (SULT2A1), a phase II conjugating enzyme known to sulfonate bile acids, hydroxysteroid dehydroepiandrosterone, and related androgens. A combination of promoter reporter gene assay and EMSA and chromatin immunoprecipitation (ChIP) assays showed that both RORα and RORγ transactivated the SULT2A1 gene promoter through their binding to a ROR response element found in the SULT2A1 gene promoter. Interestingly, this ROR response element overlaps with a previously reported constitutive androstane receptor response element on the same promoter. Down-regulation of RORα and/or RORγ by small interfering RNA inhibited the expression of endogenous SULT2A1. In primary human hepatocytes and human livers, we found a positive correlation between the expression of SULT2A1 and RORs, which further supported the regulation of SULT2A1 by RORs. We also found that the expression of RORα and RORγ was impaired in several liver disease conditions, such as steatosis/steatohepatitis, fibrosis, and hepatocellular carcinoma. The positive regulation of human SULT2A1 by RORs is opposite to the negative regulation of Sult2a1 by RORs in rodents. In summary, our results established SULT2A1 as a novel ROR target gene. The expression of RORs is a potential predictor for the expression of SULT2A1 as well as disease conditions.
Collapse
Affiliation(s)
- Zhimin Ou
- Institute of Clinical Pharmacology, Sun Yat-Sen University, Guangzhou 510080, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
67
|
Abstract
Circadian clocks maintain periodicity in internal cycles of behavior, physiology, and metabolism, enabling organisms to anticipate the 24-h rotation of the Earth. In mammals, circadian integration of metabolic systems optimizes energy harvesting and utilization across the light/dark cycle. Disruption of clock genes has recently been linked to sleep disorders and to the development of cardiometabolic disease. Conversely, aberrant nutrient signaling affects circadian rhythms of behavior. This chapter reviews the emerging relationship between the molecular clock and metabolic systems and examines evidence that circadian disruption exerts deleterious consequences on human health.
Collapse
Affiliation(s)
- Biliana Marcheva
- Department of Medicine, Feinberg School of Medicine, Northwestern University, 303 E. Superior Street, Lurie 7-107, Chicago, IL 60611, USA
| | | | | | | | | | | |
Collapse
|
68
|
Solt LA, Burris TP. Action of RORs and their ligands in (patho)physiology. Trends Endocrinol Metab 2012; 23:619-27. [PMID: 22789990 PMCID: PMC3500583 DOI: 10.1016/j.tem.2012.05.012] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 05/25/2012] [Accepted: 05/31/2012] [Indexed: 12/21/2022]
Abstract
The retinoic-acid-receptor-related orphan receptors (RORs) are members of the nuclear receptor (NR) superfamily whose activity has been implicated in several physiological and pathological processes. The RORs, specifically RORα and RORγ, are considered to be master regulators of T(H)17 cells, a recently described subset of CD4(+) T helper cells that have been demonstrated to have a pathological role in autoimmune disease. As with most members of the NR superfamily, RORs are ligand-regulated, suggesting that their activity can be modulated by synthetic ligands. Recent advances in the field have established that selective inhibition of the RORs is a viable therapeutic approach for not only the treatment of autoimmune disorders but also ROR-mediated metabolic disorders.
Collapse
MESH Headings
- Animals
- Autoimmune Diseases/drug therapy
- Autoimmune Diseases/immunology
- Circadian Rhythm/physiology
- Humans
- Ligands
- Metabolic Diseases/physiopathology
- Mice
- Nuclear Receptor Subfamily 1, Group F, Member 1/antagonists & inhibitors
- Nuclear Receptor Subfamily 1, Group F, Member 1/physiology
- Nuclear Receptor Subfamily 1, Group F, Member 3/antagonists & inhibitors
- Nuclear Receptor Subfamily 1, Group F, Member 3/physiology
- T-Lymphocytes, Helper-Inducer/drug effects
- T-Lymphocytes, Helper-Inducer/physiology
Collapse
Affiliation(s)
- Laura A Solt
- The Scripps Research Institute, Jupiter, FL 33458, USA
| | | |
Collapse
|
69
|
Pearen MA, Muscat GEO. Orphan nuclear receptors and the regulation of nutrient metabolism: understanding obesity. Physiology (Bethesda) 2012; 27:156-66. [PMID: 22689791 DOI: 10.1152/physiol.00007.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nuclear hormone receptors (NRs) are a superfamily of eukaryotic ligand-dependent transcription factors that translate endocrine, metabolic, nutritional, developmental, and pathophysiological signals into gene regulation. Members of the NR superfamily (on the basis of sequence homology) that lack identified natural and/or synthetic ligands are/were classified as "orphan" NRs. These members of the NR superfamily are abundantly expressed in tissues associated with major metabolic activity, such as skeletal muscle, adipose, and liver. Subsequently, in vivo genetic studies on these orphan NRs and exploitation of novel natural and synthetic agonists has revealed that orphan NRs regulate 1) carbohydrate, lipid, and energy homeostasis in a tissue-specific manner, and 2) the pathophysiology of dyslipidemia, obesity, Type 2 diabetes, and cardiovascular disease. This review discusses key studies that have implicated the orphan NRs as organ-specific regulators of metabolism and mediators of adverse pathophysiological effects. The emerging discovery of novel endogenous orphan NR ligands and synthetic agonists has provided the foundation for therapeutic exploitation of the orphans in the treatment of metabolic disease.
Collapse
Affiliation(s)
- Michael A Pearen
- Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia.
| | | |
Collapse
|
70
|
Peek CB, Ramsey KM, Marcheva B, Bass J. Nutrient sensing and the circadian clock. Trends Endocrinol Metab 2012; 23:312-8. [PMID: 22424658 PMCID: PMC3389335 DOI: 10.1016/j.tem.2012.02.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 02/01/2012] [Accepted: 02/02/2012] [Indexed: 12/19/2022]
Abstract
The circadian system synchronizes behavioral and physiologic processes with daily changes in the external light-dark cycle, optimizing energetic cycles with the rising and setting of the sun. Molecular clocks are organized hierarchically, with neural clocks orchestrating the daily switch between periods of feeding and fasting, and peripheral clocks generating 24h oscillations of energy storage and utilization. Recent studies indicate that clocks respond to nutrient signals and that a high-fat diet influences the period of locomotor activity under free-running conditions, a core property of the clock. A major goal is to identify the molecular basis for the reciprocal relation between metabolic and circadian pathways. Here the role of peptidergic hormones and macromolecules as nutrient signals integrating circadian and metabolic systems is highlighted.
Collapse
Affiliation(s)
- Clara B Peek
- Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine, Chicago, IL 60611, USA
| | | | | | | |
Collapse
|
71
|
Fitzsimmons RL, Lau P, Muscat GEO. Retinoid-related orphan receptor alpha and the regulation of lipid homeostasis. J Steroid Biochem Mol Biol 2012; 130:159-68. [PMID: 21723946 DOI: 10.1016/j.jsbmb.2011.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 10/18/2022]
Abstract
Many nuclear hormone receptors (NRs) control lipid, glucose and energy homeostasis in an organ specific manner. Concordantly, dysfunctional NR signalling results in metabolic disease. The Retinoic acid receptor-related orphan receptor alpha (RORα), a member of the NR1F subgroup, is expressed in metabolic tissues. Previous studies identified the role of this NR in dyslipidemia, apo-lipoprotein metabolism and atherosclerosis. Recent data is underscoring the significant role of this orphan NR in the regulation of phase I/II metabolism (bile acids, xenobiotics, steroids etc.), adiposity, insulin signalling, and glucose tolerance. Moreover, oxygenated sterols, have been demonstrated to function as native ligands and inverse agonists. This review focuses on the rapidly emerging and evolving role of RORα in the control of lipid and glucose homeostasis in major mass metabolic tissues. Article from the special issue orphan receptors.
Collapse
Affiliation(s)
- Rebecca L Fitzsimmons
- Obesity Research Centre, Institute for Molecular Bioscience, University of Queensland, Services Rd St. Lucia, Queensland, 4072 Australia
| | | | | |
Collapse
|
72
|
Burris TP, Busby SA, Griffin PR. Targeting orphan nuclear receptors for treatment of metabolic diseases and autoimmunity. ACTA ACUST UNITED AC 2012; 19:51-9. [PMID: 22284354 DOI: 10.1016/j.chembiol.2011.12.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 12/13/2011] [Accepted: 12/14/2011] [Indexed: 02/08/2023]
Abstract
The nuclear receptor (NR) superfamily is composed of 48 members in humans and includes receptors for steroid hormones, thyroid hormone, various lipids and oxysterols. This superfamily has been a rich source of drug targets for myriad diseases including inflammation, cancer, and metabolic disorders. Approximately half of the superfamily have well characterized natural ligands whereas the remaining receptors are considered orphan receptors and remain a focus of a number of investigators assessing their ability to be regulated by ligands. Here, we review recent discoveries that yield important insight into the druggability of three orphan nuclear receptors: the retinoic acid receptor-like orphan receptors (RORs), peroxisome proliferator-activated receptor γ (PPARγ), and liver receptor homolog-1 (LRH-1).
Collapse
Affiliation(s)
- Thomas P Burris
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA.
| | | | | |
Collapse
|
73
|
Crumbley C, Wang Y, Banerjee S, Burris TP. Regulation of expression of citrate synthase by the retinoic acid receptor-related orphan receptor α (RORα). PLoS One 2012; 7:e33804. [PMID: 22485150 PMCID: PMC3317774 DOI: 10.1371/journal.pone.0033804] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 02/22/2012] [Indexed: 11/19/2022] Open
Abstract
The retinoic acid receptor-related orphan receptor α (RORα) is a member of the nuclear receptor superfamily of transcription factors that plays an important role in regulation of the circadian rhythm and metabolism. Mice lacking a functional RORα display a range of metabolic abnormalities including decreased serum cholesterol and plasma triglycerides. Citrate synthase (CS) is a key enzyme of the citric acid cycle that provides energy for cellular function. Additionally, CS plays a critical role in providing citrate derived acetyl-CoA for lipogenesis and cholesterologenesis. Here, we identified a functional RORα response element (RORE) in the promoter of the CS gene. ChIP analysis demonstrates RORα occupancy of the CS promoter and a putative RORE binds to RORα effectively in an electrophoretic mobility shift assay and confers RORα responsiveness to a reporter gene in a cotransfection assay. We also observed a decrease in CS gene expression and CS enzymatic activity in the staggerer mouse, which has a mutation of in the Rora gene resulting in nonfunctional RORα protein. Furthermore, we found that SR1001 a RORα inverse agonist eliminated the circadian pattern of expression of CS mRNA in mice. These data suggest that CS is a direct RORα target gene and one mechanism by which RORα regulates lipid metabolism is via regulation of CS expression.
Collapse
Affiliation(s)
- Christine Crumbley
- Department of Molecular Therapeutics and Center for Diabetes and Metabolic Disease, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Yongjun Wang
- Department of Molecular Therapeutics and Center for Diabetes and Metabolic Disease, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Subhashis Banerjee
- Department of Molecular Therapeutics and Center for Diabetes and Metabolic Disease, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Thomas P. Burris
- Department of Molecular Therapeutics and Center for Diabetes and Metabolic Disease, The Scripps Research Institute, Jupiter, Florida, United States of America
- * E-mail:
| |
Collapse
|
74
|
Stylianou IM, Bauer RC, Reilly MP, Rader DJ. Genetic basis of atherosclerosis: insights from mice and humans. Circ Res 2012; 110:337-55. [PMID: 22267839 DOI: 10.1161/circresaha.110.230854] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Atherosclerosis is a complex and heritable disease involving multiple cell types and the interactions of many different molecular pathways. The genetic and molecular mechanisms of atherosclerosis have, in part, been elucidated by mouse models; at least 100 different genes have been shown to influence atherosclerosis in mice. Importantly, unbiased genome-wide association studies have recently identified a number of novel loci robustly associated with atherosclerotic coronary artery disease. Here, we review the genetic data elucidated from mouse models of atherosclerosis, as well as significant associations for human coronary artery disease. Furthermore, we discuss in greater detail some of these novel human coronary artery disease loci. The combination of mouse and human genetics has the potential to identify and validate novel genes that influence atherosclerosis, some of which may be candidates for new therapeutic approaches.
Collapse
Affiliation(s)
- Ioannis M Stylianou
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, 654 BRBII/III Labs, 421 Curie Boulevard, Philadelphia, Pennsylvania, 19104-6160, USA
| | | | | | | |
Collapse
|
75
|
Sahar S, Sassone-Corsi P. Regulation of metabolism: the circadian clock dictates the time. Trends Endocrinol Metab 2012; 23:1-8. [PMID: 22169754 PMCID: PMC3259741 DOI: 10.1016/j.tem.2011.10.005] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 10/30/2011] [Accepted: 10/31/2011] [Indexed: 02/06/2023]
Abstract
Circadian rhythms occur with a periodicity of approximately 24h and regulate a wide array of metabolic and physiologic functions. Accumulating epidemiological and genetic evidence indicates that disruption of circadian rhythms can be directly linked to many pathological conditions, including sleep disorders, depression, metabolic syndrome and cancer. Intriguingly, several molecular gears constituting the clock machinery have been found to establish functional interplays with regulators of cellular metabolism. Although the circadian clock regulates multiple metabolic pathways, metabolite availability and feeding behavior can in turn regulate the circadian clock. An in-depth understanding of this reciprocal regulation of circadian rhythms and cellular metabolism may provide insights into the development of therapeutic intervention against specific metabolic disorders.
Collapse
|
76
|
The REV-ERBs and RORs: molecular links between circadian rhythms and lipid homeostasis. Future Med Chem 2011; 3:623-38. [PMID: 21526899 DOI: 10.4155/fmc.11.9] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Research efforts spanning the past two decades have established a clear link between nuclear receptor function, regulation of the circadian clock and lipid homeostasis. As such, this family of receptors represents an important area of research. Recent advances in the field have identified two nuclear receptor subfamilies, the REV-ERBs and the 'retinoic acid receptor-related orphan receptors' (RORs), as critical regulators of the circadian clock with significant roles in lipid homeostasis. In this review, the latest information garnered from cutting-edge research on these two nuclear receptor subfamilies will be discussed. Through direct targeting of the REV-ERBs and RORs with synthetic ligands, generation of novel tools aimed at characterizing their function in vivo have been developed, which may lead to novel therapeutics for the treatment of metabolic disorders.
Collapse
|
77
|
Chauvet C, Vanhoutteghem A, Duhem C, Saint-Auret G, Bois-Joyeux B, Djian P, Staels B, Danan JL. Control of gene expression by the retinoic acid-related orphan receptor alpha in HepG2 human hepatoma cells. PLoS One 2011; 6:e22545. [PMID: 21818335 PMCID: PMC3144224 DOI: 10.1371/journal.pone.0022545] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 06/29/2011] [Indexed: 11/23/2022] Open
Abstract
Retinoic acid-related Orphan Receptor alpha (RORα; NR1F1) is a widely distributed nuclear receptor involved in several (patho)physiological functions including lipid metabolism, inflammation, angiogenesis, and circadian rhythm. To better understand the role of this nuclear receptor in liver, we aimed at displaying genes controlled by RORα in liver cells by generating HepG2 human hepatoma cells stably over-expressing RORα. Genes whose expression was altered in these cells versus control cells were displayed using micro-arrays followed by qRT-PCR analysis. Expression of these genes was also altered in cells in which RORα was transiently over-expressed after adenoviral infection. A number of the genes found were involved in known pathways controlled by RORα, for instance LPA, NR1D2 and ADIPOQ in lipid metabolism, ADIPOQ and PLG in inflammation, PLG in fibrinolysis and NR1D2 and NR1D1 in circadian rhythm. This study also revealed that genes such as G6PC, involved in glucose homeostasis, and AGRP, involved in the control of body weight, are also controlled by RORα. Lastly, SPARC, involved in cell growth and adhesion, and associated with liver carcinogenesis, was up-regulated by RORα. SPARC was found to be a new putative RORα target gene since it possesses, in its promoter, a functional RORE as evidenced by EMSAs and transfection experiments. Most of the other genes that we found regulated by RORα also contained putative ROREs in their regulatory regions. Chromatin immunoprecipitation (ChIP) confirmed that the ROREs present in the SPARC, PLG, G6PC, NR1D2 and AGRP genes were occupied by RORα in HepG2 cells. Therefore these genes must now be considered as direct RORα targets. Our results open new routes on the roles of RORα in glucose metabolism and carcinogenesis within cells of hepatic origin.
Collapse
Affiliation(s)
- Caroline Chauvet
- Laboratoire de Pharmacologie, Toxicologie et Signalisation Cellulaire, INSERM UMR-S-747, Centre Universitaire des Saints Pères, Université Paris Descartes, Paris, France.
| | | | | | | | | | | | | | | |
Collapse
|
78
|
Lau P, Fitzsimmons RL, Pearen MA, Watt MJ, Muscat GEO. Homozygous staggerer (sg/sg) mice display improved insulin sensitivity and enhanced glucose uptake in skeletal muscle. Diabetologia 2011; 54:1169-80. [PMID: 21279323 PMCID: PMC3071927 DOI: 10.1007/s00125-011-2046-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 12/03/2010] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Homozygous staggerer (sg/sg) mice, which have decreased and dysfunctional Rorα (also known as Rora) expression in all tissues, display a lean and dyslipidaemic phenotype. They are also resistant to (high fat) diet-induced obesity. We explored whether retinoic acid receptor-related orphan receptor (ROR) α action in skeletal muscle was involved in the regulation of glucose metabolism. METHODS We used a three-armed genomic approach, including expression profiling, ingenuity analysis and quantitative PCR validation to identify the signalling pathway(s) in skeletal muscle that are perturbed in sg/sg mice. Moreover, western analysis, functional insulin and glucose tolerance tests, and ex vivo glucose uptake assays were used to phenotypically characterise the impact of aberrant v-AKT murine thymoma viral oncogene homologue (AKT) signalling. RESULTS Homozygous and heterozygous (sg/sg and sg/+) animals exhibited decreased fasting blood glucose levels, mildly improved glucose tolerance and increased insulin sensitivity. Illumina expression profiling and bioinformatic analysis indicated the involvement of RORα in metabolic disease and phosphatidylinositol 3-kinase-AKT signalling. Quantitative PCR and western analysis validated increased AKT2 (mRNA and protein) and phosphorylation in sg/sg mice in the basal state. This was associated with increased expression of Tbc1d1 and Glut4 (also known as Slc2a4) mRNA and protein. Finally, in agreement with the phenotype, we observed increased (absolute) levels of AKT and phosphorylated AKT (in the basal and insulin stimulated states), and of (ex vivo) glucose uptake in skeletal muscle from sg/sg mice relative to wild-type littermates. CONCLUSIONS/INTERPRETATION We propose that Rorα plays an important role in regulation of the AKT2 signalling cascade, which controls glucose uptake in skeletal muscle.
Collapse
Affiliation(s)
- P. Lau
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
| | - R. L. Fitzsimmons
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
| | - M. A. Pearen
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
| | - M. J. Watt
- Department of Physiology, Monash University, Clayton, VIC Australia
| | - G. E. O. Muscat
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
| |
Collapse
|
79
|
Ermisch M, Firla B, Steinhilber D. Protein kinase A activates and phosphorylates RORα4 in vitro and takes part in RORα activation by CaMK-IV. Biochem Biophys Res Commun 2011; 408:442-6. [PMID: 21514275 DOI: 10.1016/j.bbrc.2011.04.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 11/29/2022]
Abstract
The retinoic acid related orphan receptor RORα positively regulates the transcription of genes important for cerebellar development, immune function, lipid metabolism, and circadian rhythm. In the present study, we identified protein kinase A (PKA) as RORα4 phosphorylating kinase in vitro. The primary sequence of RORα4 contains a PKA recognition motif (R-D-S99) within the c-terminal extension of the DNA-binding domain, and mutation of Ser-99 to Ala prevents RORα4 phosphorylation by PKA. Activation of PKA by dBcAMP results in a marked induction of RORα4 activity. Inhibition of PKA with the selective kinase inhibitor H89 inhibits dBcAMP mediated as well as CaMK-IV triggered increase in RORα4 transcriptional activity. The regulation of RORα activity by PKA as well as CaMK-IV provides a new link in the signalling network that regulates metabolic processes such as glycogen and lipid metabolism.
Collapse
Affiliation(s)
- Michael Ermisch
- Institute for Pharmaceutical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | | | | |
Collapse
|
80
|
Duez H, Staels B. Nuclear receptors linking circadian rhythms and cardiometabolic control. Arterioscler Thromb Vasc Biol 2010; 30:1529-34. [PMID: 20631353 DOI: 10.1161/atvbaha.110.209098] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many behavioral and physiological processes, including locomotor activity, blood pressure, body temperature, sleep (fasting)/wake (feeding) cycles, and metabolic regulation display diurnal rhythms. The biological clock ensures proper metabolic alignment of energy substrate availability and processing. Studies in animals and humans highlight a strong link between circadian disorders and altered metabolic responses and cardiovascular events. Shift work, for instance, increases the risk to develop metabolic abnormalities resembling the metabolic syndrome. Nuclear receptors have long been known as metabolic regulators. Several of them (ie, Rev-erbalpha, RORalpha, and peroxisome proliferation-activated receptors) are subjected to circadian variations and are integral components of molecular clock machinery. In turn, these nuclear receptors regulate downstream target genes in a circadian manner, acting to properly gate metabolic events to the appropriate circadian time window.
Collapse
Affiliation(s)
- Hélène Duez
- Department of Nuclear Receptors, Cardiovascular Disease and Diabetes, University of Lille Nord de France, Inserm, UDSL, and Institut Pasteur de Lille, Lille, France.
| | | |
Collapse
|
81
|
Mukherjee S, Mani S. Orphan nuclear receptors as targets for drug development. Pharm Res 2010; 27:1439-68. [PMID: 20372994 PMCID: PMC3518931 DOI: 10.1007/s11095-010-0117-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 03/04/2010] [Indexed: 12/31/2022]
Abstract
Orphan nuclear receptors regulate diverse biological processes. These important molecules are ligand-activated transcription factors that act as natural sensors for a wide range of steroid hormones and xenobiotic ligands. Because of their importance in regulating various novel signaling pathways, recent research has focused on identifying xenobiotics targeting these receptors for the treatment of multiple human diseases. In this review, we will highlight these receptors in several physiologic and pathophysiologic actions and demonstrate how their functions can be exploited for the successful development of newer drugs.
Collapse
Affiliation(s)
- Subhajit Mukherjee
- Departments of Medicine, Genetics and Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Chanin 302-D1, Bronx, New York 10461, USA
| | - Sridhar Mani
- Departments of Medicine, Genetics and Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Chanin 302-D1, Bronx, New York 10461, USA
| |
Collapse
|
82
|
Solt LA, Griffin PR, Burris TP. Ligand regulation of retinoic acid receptor-related orphan receptors: implications for development of novel therapeutics. Curr Opin Lipidol 2010; 21:204-11. [PMID: 20463469 PMCID: PMC5024716 DOI: 10.1097/mol.0b013e328338ca18] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE OF REVIEW In the late 1980s, the cloning of several nuclear receptors led to the intense search and isolation of new members of this superfamily. Despite their identification, many of these receptors were dubbed 'orphan' receptors, as their physiological ligands remained unknown. Recent reports have presented evidence for one family of orphan receptors, the retinoic acid receptor-related orphan receptors (RORs), in several pathologies, including osteoporosis, several autoimmune diseases, asthma, cancer, diabetes and obesity. The present review summarizes the studies identifying ligands for the RORs and evaluates their role as targets for potential therapeutics. RECENT FINDINGS Significant progress was made in the initial identification of ligands for the RORs when X-ray crystallographic studies identified several molecules within the ligand-binding pockets of RORalpha and RORbeta. Recently, we identified endogenous and synthetic ligands for RORalpha and RORgamma, thereby solidifying their function as ligand-dependent transcription factors. SUMMARY Recent studies have established roles for the RORs in physiological development and the advent of disease. Identification of ligands for the RORs, both endogenous and synthetic, has established these receptors as attractive new therapeutic targets for the treatment of ROR-related diseases.
Collapse
Affiliation(s)
- Laura A Solt
- The Scripps Research Institute, Jupiter, Florida 33458, USA
| | | | | |
Collapse
|
83
|
Raichur S, Fitzsimmons RL, Myers SA, Pearen MA, Lau P, Eriksson N, Wang SM, Muscat GEO. Identification and validation of the pathways and functions regulated by the orphan nuclear receptor, ROR alpha1, in skeletal muscle. Nucleic Acids Res 2010; 38:4296-312. [PMID: 20338882 PMCID: PMC2910057 DOI: 10.1093/nar/gkq180] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The retinoic acid receptor-related orphan receptor (ROR) alpha has been demonstrated to regulate lipid metabolism. We were interested in the RORα1 dependent physiological functions in skeletal muscle. This major mass organ accounts for ∼40% of the total body mass and significant levels of lipid catabolism, glucose disposal and energy expenditure. We utilized the strategy of targeted muscle-specific expression of a truncated (dominant negative) RORα1ΔDE in transgenic mice to investigate RORα1 signaling in this tissue. Expression profiling and pathway analysis indicated that RORα influenced genes involved in: (i) lipid and carbohydrate metabolism, cardiovascular and metabolic disease; (ii) LXR nuclear receptor signaling and (iii) Akt and AMPK signaling. This analysis was validated by quantitative PCR analysis using TaqMan low-density arrays, coupled to statistical analysis (with Empirical Bayes and Benjamini–Hochberg). Moreover, westerns and metabolic profiling were utilized to validate the genes, proteins and pathways (lipogenic, Akt, AMPK and fatty acid oxidation) involved in the regulation of metabolism by RORα1. The identified genes and pathways were in concordance with the demonstration of hyperglycemia, glucose intolerance, attenuated insulin-stimulated phosphorylation of Akt and impaired glucose uptake in the transgenic heterozygous Tg-RORα1ΔDE animals. In conclusion, we propose that RORα1 is involved in regulating the Akt2-AMPK signaling pathways in the context of lipid homeostasis in skeletal muscle.
Collapse
Affiliation(s)
- S Raichur
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, 4072, Australia
| | | | | | | | | | | | | | | |
Collapse
|
84
|
Wang Y, Solt LA, Burris TP. Regulation of FGF21 expression and secretion by retinoic acid receptor-related orphan receptor alpha. J Biol Chem 2010; 285:15668-73. [PMID: 20332535 DOI: 10.1074/jbc.m110.102160] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Fibroblast growth factor 21 (FGF21) is a hormone produced by fat and the liver that plays an important role in lipid metabolism. FGF21 expression is induced by peroxisome proliferator-actived receptor alpha in response to physiological conditions requiring increased fatty acid oxidation. Retinoic acid receptor-related receptor alpha (RORalpha) is another nuclear receptor that plays a critical role in lipid metabolism as well as in regulation of the circadian rhythm. In this study we demonstrate that RORalpha directly regulates the expression and secretion of FGF21. A canonical ROR response element was identified in the proximal promoter of the FGF21 gene and shown to exhibit functional activity. Overexpression of RORalpha in HepG2 cells resulted in increased expression and secretion of FGF21. Suppression of RORalpha expression caused a decrease in FGF21 expression and secretion, suggesting that RORalpha contributes to the basal expression of FGF21. These data suggest that one mechanism by which RORalpha regulates lipid metabolism may be by modulation of FGF21 secretion. Furthermore, this study identifies a clear link between RORalpha, a key regulator of the mammalian clock, and FGF21, an important hormone regulating glucose and lipid homeostasis.
Collapse
Affiliation(s)
- Yongjun Wang
- Scripps Research Institute, Jupiter, Florida 33458, USA
| | | | | |
Collapse
|
85
|
Wang Y, Kumar N, Solt LA, Richardson TI, Helvering LM, Crumbley C, Garcia-Ordonez RD, Stayrook KR, Zhang X, Novick S, Chalmers MJ, Griffin PR, Burris TP. Modulation of retinoic acid receptor-related orphan receptor alpha and gamma activity by 7-oxygenated sterol ligands. J Biol Chem 2010; 285:5013-25. [PMID: 19965867 PMCID: PMC2836105 DOI: 10.1074/jbc.m109.080614] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 12/04/2009] [Indexed: 01/07/2023] Open
Abstract
The retinoic acid receptor-related orphan receptors alpha and gamma (RORalpha (NR1F1) and RORgamma (NR1F3)) are orphan nuclear receptors and perform critical roles in regulation of development, metabolism, and immune function. Cholesterol and cholesterol sulfate have been suggested to be RORalpha ligands, but the physiological significance is unclear. To date, no endogenous RORgamma ligands have been described. Here, we demonstrate that 7-oxygenated sterols function as high affinity ligands for both RORalpha and RORgamma by directly binding to their ligand-binding domains (K(i) approximately 20 nM), modulating coactivator binding, and suppressing the transcriptional activity of the receptors. One of the 7-oxygenated sterols, 7alpha-hydroxycholesterol (7alpha-OHC), serves as a key intermediate in bile acid metabolism, and we show that 7alpha-OHC modulates the expression of ROR target genes, including Glc-6-Pase and phosphoenolpyruvate carboxykinase, in an ROR-dependent manner. Furthermore, glucose output from hepatocytes is suppressed by 7alpha-OHC functioning as an RORalpha/gamma ligand. Thus, RORalpha and RORgamma are ligand-regulated members of the NR superfamily and may serve as sensors for 7-oxygenated sterols.
Collapse
Affiliation(s)
- Yongjun Wang
- From the Scripps Research Institute, Jupiter, Florida 33458 and
| | - Naresh Kumar
- From the Scripps Research Institute, Jupiter, Florida 33458 and
| | - Laura A. Solt
- From the Scripps Research Institute, Jupiter, Florida 33458 and
| | | | | | | | | | | | - Xi Zhang
- From the Scripps Research Institute, Jupiter, Florida 33458 and
| | - Scott Novick
- From the Scripps Research Institute, Jupiter, Florida 33458 and
| | | | | | | |
Collapse
|
86
|
Kumar N, Solt LA, Conkright JJ, Wang Y, Istrate MA, Busby SA, Garcia-Ordonez RD, Burris TP, Griffin PR. The benzenesulfoamide T0901317 [N-(2,2,2-trifluoroethyl)-N-[4-[2,2,2-trifluoro-1-hydroxy-1-(trifluoromethyl)ethyl]phenyl]-benzenesulfonamide] is a novel retinoic acid receptor-related orphan receptor-alpha/gamma inverse agonist. Mol Pharmacol 2010; 77:228-36. [PMID: 19887649 PMCID: PMC2812071 DOI: 10.1124/mol.109.060905] [Citation(s) in RCA: 204] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 11/03/2009] [Indexed: 12/23/2022] Open
Abstract
Retinoic acid receptor-related orphan receptors (RORs) regulate a variety of physiological processes including hepatic gluconeogenesis, lipid metabolism, circadian rhythm, and immune function. Here we present the first high-affinity synthetic ligand for both RORalpha and RORgamma. In a screen against all 48 human nuclear receptors, the benzenesulfonamide liver X receptor (LXR) agonist N-(2,2,2-trifluoroethyl)-N-[4-[2,2,2-trifluoro-1-hydroxy-1-(trifluoromethyl)ethyl]phenyl]-benzenesulfonamide (T0901317) inhibited transactivation activity of RORalpha and RORgamma but not RORbeta. T0901317 was found to directly bind to RORalpha and RORgamma with high affinity (K(i) = 132 and 51 nM, respectively), resulting in the modulation of the receptor's ability to interact with transcriptional cofactor proteins. T0901317 repressed RORalpha/gamma-dependent transactivation of ROR-responsive reporter genes and in HepG2 cells reduced recruitment of steroid receptor coactivator-2 by RORalpha at an endogenous ROR target gene (G6Pase). Using small interference RNA, we demonstrate that repression of the gluconeogenic enzyme glucose-6-phosphatase in HepG2 cells by T0901317 is ROR-dependent and is not due to the compound's LXR activity. In summary, T0901317 represents a novel chemical probe to examine RORalpha/gamma function and an excellent starting point for the development of ROR selective modulators. More importantly, our results demonstrate that small molecules can be used to target the RORs for therapeutic intervention in metabolic and immune disorders.
Collapse
Affiliation(s)
- Naresh Kumar
- The Scripps Research Institute, Jupiter, FL 33458, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
87
|
Abstract
Circadian rhythms govern a remarkable variety of metabolic and physiological functions. Accumulating epidemiological and genetic evidence indicates that the disruption of circadian rhythms might be directly linked to cancer. Intriguingly, several molecular gears constituting the clock machinery have been found to establish functional interplays with regulators of the cell cycle, and alterations in clock function could lead to aberrant cellular proliferation. In addition, connections between the circadian clock and cellular metabolism have been identified that are regulated by chromatin remodelling. This suggests that abnormal metabolism in cancer could also be a consequence of a disrupted circadian clock. Therefore, a comprehensive understanding of the molecular links that connect the circadian clock to the cell cycle and metabolism could provide therapeutic benefit against certain human neoplasias.
Collapse
Affiliation(s)
- Saurabh Sahar
- Department of Pharmacology, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
| | | |
Collapse
|
88
|
Huang HJ, Schulman IG. Regulation of metabolism by nuclear hormone receptors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 87:1-51. [PMID: 20374700 DOI: 10.1016/s1877-1173(09)87001-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The worldwide epidemic of metabolic disease indicates that a better understanding of the pathways contributing to the pathogenesis of this constellation of diseases need to be determined. Nuclear hormone receptors comprise a superfamily of ligand-activated transcription factors that control development, differentiation, and metabolism. Over the last 15 years a growing number of nuclear receptors have been identified that coordinate genetic networks regulating lipid metabolism and energy utilization. Several of these receptors directly sample the levels of metabolic intermediates and use this information to regulate the synthesis, transport, and breakdown of the metabolite of interest. In contrast, other family members sense metabolic activity via the presence or absence of interacting proteins. The ability of these nuclear receptors to impact metabolism and inflammation will be discussed and the potential of each receptor subfamily to serve as drug targets for metabolic disease will be highlighted.
Collapse
Affiliation(s)
- Huey-Jing Huang
- Department of Biology, Exelixis Inc., 4757 Nexus Centre Drive, San Diego, California 92121, USA
| | | |
Collapse
|
89
|
Silveira AC, Morrison MA, Ji F, Xu H, Reinecke JB, Adams SM, Arneberg TM, Janssian M, Lee JE, Yuan Y, Schaumberg DA, Kotoula MG, Tsironi EE, Tsiloulis AN, Chatzoulis DZ, Miller JW, Kim IK, Hageman GS, Farrer LA, Haider NB, DeAngelis MM. Convergence of linkage, gene expression and association data demonstrates the influence of the RAR-related orphan receptor alpha (RORA) gene on neovascular AMD: a systems biology based approach. Vision Res 2009; 50:698-715. [PMID: 19786043 DOI: 10.1016/j.visres.2009.09.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 09/04/2009] [Accepted: 09/18/2009] [Indexed: 12/28/2022]
Abstract
To identify novel genes and pathways associated with AMD, we performed microarray gene expression and linkage analysis which implicated the candidate gene, retinoic acid receptor-related orphan receptor alpha (RORA, 15q). Subsequent genotyping of 159 RORA single nucleotide polymorphisms (SNPs) in a family-based cohort, followed by replication in an unrelated case-control cohort, demonstrated that SNPs and haplotypes located in intron 1 were significantly associated with neovascular AMD risk in both cohorts. This is the first report demonstrating a possible role for RORA, a receptor for cholesterol, in the pathophysiology of AMD. Moreover, we found a significant interaction between RORA and the ARMS2/HTRA1 locus suggesting a novel pathway underlying AMD pathophysiology.
Collapse
Affiliation(s)
- Alexandra C Silveira
- Ocular Molecular Genetics Institute and Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
90
|
Duez H, Staels B. Rev-erb-alpha: an integrator of circadian rhythms and metabolism. J Appl Physiol (1985) 2009; 107:1972-80. [PMID: 19696364 DOI: 10.1152/japplphysiol.00570.2009] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The endogenous circadian clock ensures daily rhythms in diverse behavioral and physiological processes, including locomotor activity and sleep/wake cycles, but also food intake patterns. Circadian rhythms are generated by an internal clock system, which synchronizes these daily variations to the day/night alternance. In addition, circadian oscillations may be reset by the time of food availability in peripheral metabolic organs. Circadian rhythms are seen in many metabolic pathways (glucose and lipid metabolism, etc.) and endocrine secretions (insulin, etc.). As a consequence, misalignment of the internal timing system vs. environmental zeitgebers (light, for instance), as experienced during jetlag or shift work, may result in disruption of physiological cycles of fuel utilization or energy storage. A large body of evidence from both human and animal studies now points to a relationship between circadian disorders and altered metabolic response, suggesting that circadian and metabolic regulatory networks are tightly connected. After a review of the current understanding of the molecular circadian core clock, we will discuss the hypothesis that clock genes themselves link the core molecular clock and metabolic regulatory networks. We propose that the nuclear receptor and core clock component Rev-erb-alpha behaves as a gatekeeper to timely coordinate the circadian metabolic response.
Collapse
Affiliation(s)
- Hélène Duez
- University Lille Nord de France, Lille, France.
| | | |
Collapse
|
91
|
Duez H, Duhem C, Laitinen S, Patole PS, Abdelkarim M, Bois-Joyeux B, Danan JL, Staels B. Inhibition of adipocyte differentiation by RORalpha. FEBS Lett 2009; 583:2031-6. [PMID: 19450581 DOI: 10.1016/j.febslet.2009.05.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 04/27/2009] [Accepted: 05/08/2009] [Indexed: 01/27/2023]
Abstract
Here we show that gene expression of the nuclear receptor RORalpha is induced during adipogenesis, with RORalpha4 being the most abundantly expressed isoform in human and murine adipose tissue. Over-expression of RORalpha4 in 3T3-L1 cells impairs adipogenesis as shown by the decreased expression of adipogenic markers and lipid accumulation, accompanied by decreased free fatty acid and glucose uptake. By contrast, mouse embryonic fibroblasts from staggerer mice, which carry a mutation in the RORalpha gene, differentiate more efficiently into mature adipocytes compared to wild-type cells, a phenotype which is reversed by ectopic RORalpha4 restoration.
Collapse
MESH Headings
- 3T3-L1 Cells
- Adipocytes/cytology
- Adipocytes/metabolism
- Adipogenesis/genetics
- Adipogenesis/physiology
- Adult
- Animals
- Cell Differentiation/genetics
- Cell Differentiation/physiology
- Fatty Acids, Nonesterified/metabolism
- Gene Expression
- Glucose/metabolism
- Humans
- In Vitro Techniques
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Neurologic Mutants
- Nuclear Receptor Subfamily 1, Group F, Member 1
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/deficiency
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Trans-Activators/deficiency
- Trans-Activators/genetics
- Trans-Activators/metabolism
Collapse
Affiliation(s)
- Hélène Duez
- Institut Pasteur de Lille, Département d'Athérosclérose, Lille F-59019, France
| | | | | | | | | | | | | | | |
Collapse
|
92
|
Jetten AM. Retinoid-related orphan receptors (RORs): critical roles in development, immunity, circadian rhythm, and cellular metabolism. NUCLEAR RECEPTOR SIGNALING 2009; 7:e003. [PMID: 19381306 PMCID: PMC2670432 DOI: 10.1621/nrs.07003] [Citation(s) in RCA: 499] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 03/18/2009] [Indexed: 12/11/2022]
Abstract
The last few years have witnessed a rapid increase in our knowledge of the retinoid-related orphan receptors RORα, -β, and -γ (NR1F1-3), their mechanism of action, physiological functions, and their potential role in several pathologies. The characterization of ROR-deficient mice and gene expression profiling in particular have provided great insights into the critical functions of RORs in the regulation of a variety of physiological processes. These studies revealed that RORα plays a critical role in the development of the cerebellum, that both RORα and RORβ are required for the maturation of photoreceptors in the retina, and that RORγ is essential for the development of several secondary lymphoid tissues, including lymph nodes. RORs have been further implicated in the regulation of various metabolic pathways, energy homeostasis, and thymopoiesis. Recent studies identified a critical role for RORγ in lineage specification of uncommitted CD4+ T helper cells into Th17 cells. In addition, RORs regulate the expression of several components of the circadian clock and may play a role in integrating the circadian clock and the rhythmic pattern of expression of downstream (metabolic) genes. Study of ROR target genes has provided insights into the mechanisms by which RORs control these processes. Moreover, several reports have presented evidence for a potential role of RORs in several pathologies, including osteoporosis, several autoimmune diseases, asthma, cancer, and obesity, and raised the possibility that RORs may serve as potential targets for chemotherapeutic intervention. This prospect was strengthened by recent evidence showing that RORs can function as ligand-dependent transcription factors.
Collapse
Affiliation(s)
- Anton M Jetten
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA.
| |
Collapse
|
93
|
Juan T, Véniant MM, Helmering J, Babij P, Baker DM, Damore MA, Bass MB, Gyuris T, Chhoa M, Li CM, Ebeling C, Amato J, Carlson GA, Lloyd DJ. Identification of three loci affecting HDL-cholesterol levels in a screen for chemically induced recessive mutations in mice. J Lipid Res 2008; 50:534-545. [PMID: 18974039 DOI: 10.1194/jlr.m800471-jlr200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We conducted a genome-wide screen using the mutagen N-ethyl-N-nitrosourea to identify recessive mutations in genes that lead to altered lipid traits in mice. We screened 7,546 G3 mice that were of mixed C57BL/6J (B6) x C3.SW-H2(b)/SnJ (C3) genomes and identified three pedigrees with differences in plasma HDL-cholesterol. Genome scan analyses mapped three distinct loci to chromosomes 3, 4, and 7. An S1748L missense mutation was identified in ABCA1 in one pedigree with undetectable levels of HDL-cholesterol and resulted in reduced protein levels. This phenotype was completely penetrant, semi-dominant, and cosegregated with high plasma triglycerides. Mice in a second pedigree had very high levels of plasma total cholesterol and HDL-cholesterol (up to 800 mg/dl total cholesterol). Despite a high degree of phenotype lability and reduced penetrance, an I68N missense mutation was identified in the transcription factor CCAAT/enhancer binding protein alpha (C/EBPalpha). Finally, a second high HDL-cholesterol pedigree of mice, again with a highly labile phenotype and reduced penetrance, was mapped to a 7 Mb locus on chromosome 3. These results illustrate the use of a hybrid background for simultaneous screening and mapping of mutagenized pedigrees of mice and identification of three novel alleles of HDL-cholesterol phenotypes.
Collapse
Affiliation(s)
- Todd Juan
- Department of Protein Sciences, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Murielle M Véniant
- Department of Metabolic Disorders, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Joan Helmering
- Department of Metabolic Disorders, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Philip Babij
- Department of Metabolic Disorders, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Daniel M Baker
- Department of Molecular Sciences, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Michael A Damore
- Department of Molecular Sciences, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Michael B Bass
- Department of Computational Biology, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Tibor Gyuris
- Department of Protein Sciences, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Mark Chhoa
- Department of Protein Sciences, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Chi-Ming Li
- Department of Protein Sciences, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320
| | - Chris Ebeling
- McLaughlin Research Institute, 1520 23rd Street South, Great Falls, MT 59405
| | - Julie Amato
- McLaughlin Research Institute, 1520 23rd Street South, Great Falls, MT 59405
| | - George A Carlson
- McLaughlin Research Institute, 1520 23rd Street South, Great Falls, MT 59405
| | - David J Lloyd
- Department of Metabolic Disorders, Amgen, Inc., One Amgen Centre Drive, Thousand Oaks, CA 91320.
| |
Collapse
|
94
|
Abstract
Circadian rhythms are normal variations in physiological processes that occur over the period of a day. These rhythms are essential for the organism since they allow anticipatory metabolic regulations to prepare for the up-coming feeding or rest period. Disturbances of the biological clock predispose to metabolic disorders such as dyslipidaemia, insulin resistance and obesity. Moreover, certain pathological events, such as cardiovascular accidents (myocardial infarction, stroke) occur more frequently at specific times of the day. The nuclear receptors Rev-erbalpha and RORalpha are clock components involved in the regulation of the core clock circuitry. They are also important regulators of lipid and lipoprotein metabolism, adipogenesis and vascular inflammation. Moreover, they cross-talk with several other nuclear receptors controlling energy homeostasis. Therefore, Rev-erbalpha and RORalpha may play a central role in the coordination of metabolic processes and circadian outputs.
Collapse
Affiliation(s)
- Hélène Duez
- Institut Pasteur de Lille, 1, rue Calmette, BP 245, F-59019 Lille, France
| | | |
Collapse
|
95
|
Lau P, Fitzsimmons RL, Raichur S, Wang SCM, Lechtken A, Muscat GE. The Orphan Nuclear Receptor, RORα, Regulates Gene Expression That Controls Lipid Metabolism. J Biol Chem 2008; 283:18411-21. [DOI: 10.1074/jbc.m710526200] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
96
|
Lechtken A. [ROR-alpha--a potential target against overweight?]. PHARMAZIE IN UNSERER ZEIT 2008; 37:353-354. [PMID: 18729284 DOI: 10.1002/pauz.200890068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
97
|
Wada T, Kang HS, Angers M, Gong H, Bhatia S, Khadem S, Ren S, Ellis E, Strom SC, Jetten AM, Xie W. Identification of oxysterol 7alpha-hydroxylase (Cyp7b1) as a novel retinoid-related orphan receptor alpha (RORalpha) (NR1F1) target gene and a functional cross-talk between RORalpha and liver X receptor (NR1H3). Mol Pharmacol 2007; 73:891-9. [PMID: 18055760 DOI: 10.1124/mol.107.040741] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The retinoid-related orphan receptors (RORs) and liver X receptors (LXRs) were postulated to have distinct functions. RORs play a role in tissue development and circadian rhythm, whereas LXRs are sterol sensors that affect lipid homeostasis. In this study, we revealed a novel function of RORalpha (NR1F1) in regulating the oxysterol 7alpha-hydroxylase (Cyp7b1), an enzyme critical for the homeostasis of cholesterol, bile acids, and oxysterols. The expression of Cyp7b1 gene was suppressed in the RORalpha null (RORalpha(sg/sg)) mice, suggesting RORalpha as a positive regulator of Cyp7b1. Promoter analysis established Cyp7b1 as a transcriptional target of RORalpha, and transfection of RORalpha induced the expression of endogenous Cyp7b1 in the liver. Interestingly, Cyp7b1 regulation seemed to be RORalpha-specific, because RORgamma had little effect. Reporter gene analysis showed that the activation of Cyp7b1 gene promoter by RORalpha was suppressed by LXRalpha (NR1H3), whereas RORalpha inhibited both the constitutive and ligand-dependent activities of LXRalpha. The mutual suppression between RORalpha and LXR was supported by the in vivo observation that loss of RORalpha increased the expression of selected LXR target genes, leading to hepatic triglyceride accumulation. Likewise, mice deficient of LXR alpha and beta isoforms showed activation of selected RORalpha target genes. Our results have revealed a novel role for RORalpha and a functional interplay between RORalpha and LXR in regulating endo- and xenobiotic genes, which may have broad implications in metabolic homeostasis.
Collapse
Affiliation(s)
- Taira Wada
- Center for Pharmacogenetics, 633 Salk Hall, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
98
|
Duez H, Staels B. Rev-erbα gives a time cue to metabolism. FEBS Lett 2007; 582:19-25. [PMID: 17765229 DOI: 10.1016/j.febslet.2007.08.032] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 08/13/2007] [Accepted: 08/14/2007] [Indexed: 11/17/2022]
Abstract
Normal physiological processes are under control of circadian rhythms. Moreover, certain pathological events, such as cardiovascular accidents (myocardial infarction, stroke) occur more frequently at specific times of the day. Recent observations demonstrate a causal relationship between alterations in circadian rhythmicity and metabolic disorders. Disruption of clock genes results in dyslipidemia, insulin resistance and obesity, all predisposing to atherosclerosis. The nuclear receptor Rev-erb alpha is part of the clock circuitry and plays an important role in keeping proper timing of the clock. Rev-erb alpha also regulates lipid metabolism, adipogenesis and vascular inflammation. Interestingly, Rev-erb alpha also cross-talks with several other nuclear receptors involved in energy homeostasis. Therefore Rev-erb alpha may serve to couple metabolic and circadian signals.
Collapse
Affiliation(s)
- Hélène Duez
- Institut Pasteur de Lille, Lille F-59019, France
| | | |
Collapse
|
99
|
Lechtken A, Hörnig M, Werz O, Corvey N, Zündorf I, Dingermann T, Brandes R, Steinhilber D. Extracellular signal-regulated kinase-2 phosphorylates RORalpha4 in vitro. Biochem Biophys Res Commun 2007; 358:890-6. [PMID: 17512500 DOI: 10.1016/j.bbrc.2007.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Accepted: 05/03/2007] [Indexed: 11/19/2022]
Abstract
The retinoic acid related orphan receptor RORalpha activates transcription of genes that play an important role in cerebellar development, the protection against age-related degenerative processes, the regulation of inflammatory responses, and is one of the pivotal participants that control the circadian rhythmicity in the core-clock of mammals. We identified the extracellular signal-regulated kinase 2 (ERK-2) as RORalpha4 phosphorylating kinase in vitro. The primary sequence of RORalpha4 contains an ERK-2 recognition motif (P-L-T(128)-P) within the hinge domain, and mutation of Thr-128 to Ala prevents RORalpha4 phosphorylation by ERK. The RORalpha4-T128A mutant exhibits an increased DNA-binding affinity, an increased transcriptional activity and, in the interplay with the opponent RevErbalpha, acts as a stronger competitor at ROR response elements than RORalpha4-WT.
Collapse
Affiliation(s)
- Adriane Lechtken
- Institute of Pharmaceutical Chemistry/ZAFES, Johann Wolfgang Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany
| | | | | | | | | | | | | | | |
Collapse
|
100
|
Haidar B, Kiss RS, Sarov-Blat L, Brunet R, Harder C, McPherson R, Marcel YL. Cathepsin D, a Lysosomal Protease, Regulates ABCA1-mediated Lipid Efflux. J Biol Chem 2006; 281:39971-81. [PMID: 17032648 DOI: 10.1074/jbc.m605095200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To identify genes involved in the regulation of plasma high density lipoprotein (HDL) cholesterol (HDL-C) levels, patients with low HDL-C and age- and sex-matched controls (normal HDL-C) were extensively characterized. Comparative transcriptome analysis was carried out in cholesterol-loaded monocyte-derived macrophages from low HDL subjects segregated into groups with or without cholesterol efflux defects or ABCA1 mutations. Clusters of differentially regulated genes were evident in the low HDL groups as compared with controls. Of particular note, expression of cathepsin D (CTSD), a lysosomal proteinase, was reduced by approximately 50% in monocyte-derived macrophages of low HDL-C subjects, most significantly those with cholesterol efflux defects but without mutations in ABCA1 (p < 0.01). These results were verified by reverse transcription-PCR and replicated in a second cohort. We show here that blocking the activity or expression of CTSD, by pepstatin or CTSD small interfering RNA, respectively, reduced ABCA1 expression and protein abundance in both macrophages and CHO cells and apolipoprotein A-I-mediated lipid efflux by more than 70%. Conversely, expression of CTSD increased both ABCA1 mRNA expression and cellular ABCA1 protein. Consistent with its role in the proteolytic processing of prosaposin, inactivation of CTSD function resulted in the accumulation of glycosphingo-lipid and free cholesterol in late endosomes/lysosomes, a phenotype similar to NPC1 deficiency. Inhibition of CTSD also caused retention of ABCA1 in lysosomal compartments, reducing its trafficking to the plasma membrane. These studies demonstrate a novel and potentially important role for CTSD in intracellular cholesterol trafficking and ABCA1-mediated efflux. Therefore, decreased CTSD expression may contribute to low plasma HDL-C levels.
Collapse
Affiliation(s)
- Bassam Haidar
- Lipoprotein and Atherosclerosis Research Group, University of Ottawa Heart Institute, Ottawa, Ontario, K1Y 4W7, Canada
| | | | | | | | | | | | | |
Collapse
|