Orphan Nuclear Receptors and the Regulation of Nutrient Metabolism: Understanding Obesity

Physiology ◽  
2012 ◽  
Vol 27 (3) ◽  
pp. 156-166 ◽  
Author(s):  
Michael A. Pearen ◽  
George E. O. Muscat
Keyword(s):  
Nuclear Receptors ◽  
Energy Homeostasis ◽  
Hormone Receptors ◽  
Orphan Nuclear Receptors ◽  
Nutrient Metabolism ◽  
Genetic Studies ◽  
Specific Manner ◽  
Organ Specific

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.

scholarly journals Function of Nr4a Orphan Nuclear Receptors in Proliferation, Apoptosis and Fuel Utilization Across Tissues

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1373 ◽  
Author(s):  
Herring ◽  
Elison ◽  
Tessem
Keyword(s):  
Transcription Factors ◽  
Family Member ◽  
Nuclear Receptors ◽  
Hormone Receptors ◽  
Cellular Proliferation ◽  
Nuclear Hormone Receptors ◽  
Fuel Utilization ◽  
Orphan Nuclear Receptors ◽  
Tissue Specific ◽  
Specific Effects

The Nr4a family of nuclear hormone receptors is composed of three members—Nr4a1/Nur77, Nr4a2/Nurr1 and Nr4a3/Nor1. While currently defined as ligandless, these transcription factors have been shown to regulate varied processes across a host of tissues. Of particular interest, the Nr4a family impinge, in a tissue dependent fashion, on cellular proliferation, apoptosis and fuel utilization. The regulation of these processes occurs through both nuclear and non-genomic pathways. The purpose of this review is to provide a balanced perspective of the tissue specific and Nr4a family member specific, effects on cellular proliferation, apoptosis and fuel utilization.

scholarly journals Targeting Orphan Nuclear Receptors NR4As for Energy Homeostasis and Diabetes

2020 ◽  
Vol 11 ◽  
Author(s):  
Chenyang Zhang ◽  
Bin Zhang ◽  
Xuelian Zhang ◽  
Guibo Sun ◽  
Xiaobo Sun
Keyword(s):  
Nuclear Receptors ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Orphan Nuclear Receptors ◽  
Critical Function ◽  
Carbohydrate And Lipid Metabolism ◽  
Regulatory Effects ◽  
Treatment Of Obesity ◽  
Nuclear Receptor Family ◽  
Receptor Family

Orphan nuclear receptors are important members of the nuclear receptor family and may regulate cell proliferation, metabolism, differentiation, and apoptosis. NR4As, a subfamily of orphan nuclear receptors, have been reported to play key roles in carbohydrate and lipid metabolism and energy homeostasis. Popularity of obesity has resulted in a series of metabolic diseases such as diabetes and its complications. While imbalance of energy intake and expenditure is the main cause of obesity, the concrete mechanism of obesity has not been fully understood. It has been reported that NR4As have significant regulatory effects on energy homeostasis and diabetes and are expected to become new targets for discovering drugs for metabolic syndrome. A number of studies have demonstrated that abnormalities in metabolism induced by altered levels of NR4As may contribute to numerous diseases, such as chronic inflammation, tumorigenesis, diabetes and its complications, atherosclerosis, and other cardiovascular diseases. However, systematic reviews focusing on the roles of NR4As in mediating energy homeostasis and diabetes remain limited. Therefore, this article reviews the structure and regulation of NR4As and their critical function in energy homeostasis and diabetes, as well as small molecules that may regulate NR4As. Our work is aimed at providing valuable support for the research and development of drugs targeting NR4As for the treatment of obesity and related metabolic diseases.

scholarly journals The orphan nuclear receptors at their 25-year reunion

2013 ◽  
Vol 51 (3) ◽  
pp. T115-T140 ◽  
Author(s):  
Shannon E Mullican ◽  
Joanna R DiSpirito ◽  
Mitchell A Lazar
Keyword(s):  
Nuclear Receptors ◽  
Hormone Receptors ◽  
Steroid Hormone ◽  
Steroid Hormone Receptors ◽  
Biological Processes ◽  
Orphan Nuclear Receptors ◽  
Orphan Receptors ◽  
Critical Insight ◽  
Genomic Regions ◽  
Insight Into

The nuclear receptor superfamily includes many receptors, identified based on their similarity to steroid hormone receptors but without a known ligand. The study of how these receptors are diversely regulated to interact with genomic regions to control a plethora of biological processes has provided critical insight into development, physiology, and the molecular pathology of disease. Here we provide a compendium of these so-called orphan receptors and focus on what has been learned about their modes of action, physiological functions, and therapeutic promise.

scholarly journals Minireview: Genomics Versus Orphan Nuclear Receptors—A Half-Time Report

2002 ◽  
Vol 16 (6) ◽  
pp. 1135-1144
Author(s):  
Timothy M. Willson ◽  
John T. Moore
Keyword(s):  
Nuclear Receptors ◽  
Drug Targets ◽  
Hormone Receptors ◽  
Receptor Gene ◽  
Orphan Nuclear Receptors ◽  
Orphan Receptors ◽  
Genomic Technologies ◽  
Full Complement ◽  
And Function ◽  
The Impact

Abstract Following the successful cloning of the orphan nuclear receptors during the 1990s we entered the 21st century with knowledge of the full complement of human nuclear receptors. Many of these proteins are ligand-activated transcription factors that act as the cognate receptors for steroid, retinoid, and thyroid hormones. In addition to these well characterized endocrine hormone receptors, there are a large number of orphan receptors of which less is known about the nature and function of their ligands. The task of deciphering the physiological function of these orphan receptors has been aided by a new generation of genomic technologies. Through application of chemical, structural, and functional genomics, several orphan nuclear receptors have emerged as pharmaceutical drug targets for the treatment of important human diseases. The significant progress that has been made in the functional analysis of more than half of the nuclear receptor gene family provides an opportunity to review the impact of genomics in this endeavor.

scholarly journals BAF60a Mediates Critical Interactions between Nuclear Receptors and the BRG1 Chromatin-Remodeling Complex for Transactivation

2003 ◽  
Vol 23 (17) ◽  
pp. 6210-6220 ◽  
Author(s):  
Pei-Wen Hsiao ◽  
Christy J. Fryer ◽  
Kevin W. Trotter ◽  
Weidong Wang ◽  
Trevor K. Archer
Keyword(s):  
Nuclear Receptors ◽  
Chromatin Remodeling ◽  
Molecular Mechanisms ◽  
Hormone Receptors ◽  
Nuclear Receptor Coactivators ◽  
Chromatin Remodeling Complex ◽  
Truncation Mutant ◽  
Promoter Recruitment

ABSTRACT Nuclear hormone receptors are ligand-dependent transcriptional regulators that modulate chromatin structure. However, the precise molecular mechanisms by which receptors recruit chromatin-remodeling activity are not fully elucidated. We show that in the absence of its ligand-binding domain, the glucocorticoid receptor (GR) is able to interact with both nuclear receptor coactivators and the BRG1 chromatin-remodeling complex in vivo. Individually, the GR makes direct interactions with BRG1-associated factor 60a (BAF60a) and BAF57, but not with BRG1, BAF155, or BAF170. Further, BAF60a possesses at least two interaction surfaces, one for GR and BRG1 and a second for BAF155 and BAF170. A GR mutant, GR(R488Q), that fails to interact with BAF60a in vitro has reduced chromatin-remodeling activity and reduced transcriptional activity from the promoter assembled as chromatin in vivo. Stable expression of a BAF60a truncation mutant, BAF60a4-140, caused chromatin-specific loss of GR functions in vivo. In the presence of the BAF60a mutant, the GR fails to interact with the BRG1 complex and consequently is also deficient in its ability to activate transcription from chromatin. Thus, in addition to previously identified BAF250, BAF60a may provide another critical and direct link between nuclear receptors and the BRG1 complex that is required for promoter recruitment and subsequent chromatin remodeling.

Orphan nuclear receptors: therapeutic opportunities in skeletal muscle

2006 ◽  
Vol 291 (2) ◽  
pp. C203-C217 ◽  
Author(s):  
Aaron G. Smith ◽  
George E. O. Muscat
Keyword(s):  
Cardiovascular Disease ◽  
Skeletal Muscle ◽  
Energy Expenditure ◽  
Nuclear Receptors ◽  
Hormone Receptors ◽  
Blood Lipid ◽  
Orphan Nuclear Receptors ◽  
Blood Lipid Profile ◽  
Total Body Mass ◽  
Liver And Kidney

Nuclear hormone receptors (NRs) are ligand-dependent transcription factors that bind DNA and translate physiological signals into gene regulation. The therapeutic utility of NRs is underscored by the diversity of drugs created to manage dysfunctional hormone signaling in the context of reproductive biology, inflammation, dermatology, cancer, and metabolic disease. For example, drugs that target nuclear receptors generate over $10 billion in annual sales. Almost two decades ago, gene products were identified that belonged to the NR superfamily on the basis of DNA and protein sequence identity. However, the endogenous and synthetic small molecules that modulate their action were not known, and they were denoted orphan NRs. Many of the remaining orphan NRs are highly enriched in energy-demanding major mass tissues, including skeletal muscle, brown and white adipose, brain, liver, and kidney. This review focuses on recently adopted and orphan NR function in skeletal muscle, a tissue that accounts for ∼35% of the total body mass and energy expenditure, and is a major site of fatty acid and glucose utilization. Moreover, this lean tissue is involved in cholesterol efflux and secretes that control energy expenditure and adiposity. Consequently, muscle has a significant role in insulin sensitivity, the blood lipid profile, and energy balance. Accordingly, skeletal muscle plays a considerable role in the progression of dyslipidemia, diabetes, and obesity. These are risk factors for cardiovascular disease, which is the the foremost cause of global mortality (>16.7 million deaths in 2003). Therefore, it is not surprising that orphan NRs and skeletal muscle are emerging as therapeutic candidates in the battle against dyslipidemia, diabetes, obesity, and cardiovascular disease.

scholarly journals The Role of Peroxisome Proliferator-Activated Receptors in Colorectal Cancer

PPAR Research ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Joo-In Park ◽  
Jong-Young Kwak
Keyword(s):  
Colorectal Cancer ◽  
Dietary Fat ◽  
Energy Homeostasis ◽  
Hormone Receptors ◽  
Clinical Implications ◽  
Peroxisome Proliferator ◽  
Fat Intake ◽  
Nutrient Metabolism ◽  
Peroxisome Proliferator Activated Receptors

Colorectal cancer is one of the most common cancers in the world. Dietary fat intake is a major risk factor for colorectal cancer. Some nuclear hormone receptors play an important role in regulating nutrient metabolism and energy homeostasis. Among these receptors, special attention has been focused on the role of peroxisome proliferator-activated receptors (PPARs) in colorectal cancer, because PPARs are involved in regulation of lipid and carbohydrate metabolism. PPARs are ligand-activated intracellular transcription factors. The PPAR subfamily consists of three subtypes encoded by distinct genes named PPARα, PPARβ/δ, and PPARγ. PPARγis the most extensively studied subtype of PPARs. Even though many investigators have studied the expression and clinical implications of PPARs in colorectal cancer, there are still many controversies about the role of PPARs in colorectal cancer. In this paper, the recent progresses in understanding the role of PPARs in colorectal cancer are summarized.

scholarly journals Mitochondrial Dysfunction, Insulin Resistance, and Potential Genetic Implications

Endocrinology ◽  
2020 ◽  
Vol 161 (4) ◽  
Author(s):  
Panjamaporn Sangwung ◽  
Kitt Falk Petersen ◽  
Gerald I Shulman ◽  
Joshua W Knowles
Keyword(s):  
Insulin Resistance ◽  
Mitochondrial Function ◽  
Ex Vivo ◽  
Critical Role ◽  
Whole Body ◽  
Genetic Studies ◽  
Cellular Energy

Abstract Insulin resistance (IR) is fundamental to the development of type 2 diabetes (T2D) and is present in most prediabetic (preDM) individuals. Insulin resistance has both heritable and environmental determinants centered on energy storage and metabolism. Recent insights from human genetic studies, coupled with comprehensive in vivo and ex vivo metabolic studies in humans and rodents, have highlighted the critical role of reduced mitochondrial function as a predisposing condition for ectopic lipid deposition and IR. These studies support the hypothesis that reduced mitochondrial function, particularly in insulin-responsive tissues such as skeletal muscle, white adipose tissue, and the liver, is inextricably linked to tissue and whole body IR through the effects on cellular energy balance. Here we discuss these findings as well as address potential mechanisms that serve as the nexus between mitochondrial malfunction and IR.

scholarly journals In vivo FirreandDxz4deletion elucidates roles for autosomal gene regulation

2019 ◽  
Author(s):  
Daniel Andergassen ◽  
Zachary D. Smith ◽  
Jordan P. Lewandowski ◽  
Chiara Gerhardinger ◽  
Alexander Meissner ◽  
...  
Keyword(s):  
Gene Regulation ◽  
X Chromosome ◽  
Autosomal Gene ◽  
Double Deletion ◽  
Gene Sets ◽  
Specific Manner ◽  
Main Driver ◽  
Organ Specific ◽  
Transcriptional Effect

AbstractRecent evidence has determined that the conserved X chromosome “mega-structures” controlled by theFirreandDxz4alleles are not required for X chromosome inactivation (XCI) in cell lines. Here we determined thein vivocontribution of these alleles by generating mice carrying a single or double deletion ofFirreandDxz4. We found that these mutants are viable, fertile and show no defect in random or imprinted XCI. However, the lack of these elements results in many dysregulated genes on autosomes in an organ-specific manner. By comparing the dysregulated genes between the single and double deletion, we identified superloop, megadomain, andFirrelocus dependent gene sets. The largest transcriptional effect was observed in all strains lacking theFirrelocus, indicating that this locus is the main driver for these autosomal expression signatures. Collectively, these findings suggest that these X-linked loci are involved in autosomal gene regulation rather than XCI biology.

Health effects associated with phthalate activity on nuclear receptors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Thoin Farzana Begum ◽  
David Carpenter
Keyword(s):  
Health Effects ◽  
Nuclear Receptors ◽  
Energy Homeostasis ◽  
Reproductive Function ◽  
Normal Function ◽  
Consumer Products ◽  
Peroxisome Proliferator ◽  
Limited Information ◽  
Potential Health

Abstract Phthalates are endocrine disruptors, widely used as plasticizers to impart flexibility in plastics, and as solvents in personal care products. Due to their nearly ubiquitous use in consumer products, most humans are exposed to phthalates daily. There has been extensive research on the reproductive health effects associated with phthalate exposure, but less attention has been paid to other actions. This review aims to summarize the known action of phthalates on different nuclear receptors. Some phthalates bind to and activate the estrogen receptor, making them weakly estrogenic. However, other phthalates antagonize androgen receptors. Some high molecular weight phthalates antagonize thyroid receptors, affecting metabolism. Several phthalates activate and interfere with the normal function of different peroxisome proliferator-activated receptors (PPARs), receptors that have critical roles in lipid metabolism and energy homeostasis. Some phthalates activate the aryl hydrocarbon receptor, which is critical for xenobiotic metabolism. Although phthalates have a short half-life in vivo, because people are continuously exposed, studies should examine the health effects of phthalates associated with long-term exposure. There is limited research on the effects of phthalates on health outcomes aside from reproductive function, particularly concerning are childhood adiposity, behavior, and learning. There is also limited information on actions of phthalates not mediated via nuclear receptors. Humans are exposed to multiple chemicals simultaneously, and how chemical mixtures act on nuclear receptor activity needs study. Although we know a great deal about phthalates, there is still much that remains uncertain. Future studies need to further examine their other potential health effects.

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