scholarly journals The Nuclear Receptor-Coactivator Interaction Surface as a Target for Peptide Antagonists of the Peroxisome Proliferator-Activated Receptors

2007 ◽  
Vol 21 (10) ◽  
pp. 2361-2377 ◽  
Author(s):  
Niharika B. Mettu ◽  
Thomas B. Stanley ◽  
Mary A. Dwyer ◽  
Michelle S. Jansen ◽  
John E. Allen ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Target Genes ◽  
Binding Motif ◽  
Peroxisome Proliferator ◽  
Constitutive Activity ◽  
Phage Display Technology ◽  
Nuclear Receptor Coactivator ◽  
Peroxisome Proliferator Activated Receptors ◽  
Interaction Surface

Abstract The peroxisome proliferator-activated receptors (PPARα, PPARδ, and PPARγ) constitute a family of nuclear receptors that regulates metabolic processes involved in lipid and glucose homeostasis. Although generally considered to function as ligand-regulated receptors, all three PPARs exhibit a high level of constitutive activity that may result from their stimulation by intracellularly produced endogenous ligands. Consequently, complete inhibition of PPAR signaling requires the development of inverse agonists. However, the currently available small molecule antagonists for the PPARs function only as partial agonists, or their efficacy is not sufficient to inhibit the constitutive activity of these receptors. Due to the lack of efficacious antagonists that interact with the ligand-binding domain of the PPARs, we decided to target an interaction that is central to nuclear receptor-mediated gene transcription: the nuclear receptor-coactivator interaction. We utilized phage display technology to identify short LXXLL-containing peptides that bind to the PPARs. Analysis of these peptides revealed a consensus binding motif consisting of HPLLXXLL. Cross-screening of these peptides for binding to other nuclear receptors enabled the identification of a high-affinity PPAR-selective peptide that has the ability to repress PPARγ1-dependent transcription of transfected reporter genes. Most importantly, when introduced into HepG2 cells, the peptide inhibited the expression of endogenous PPARγ1 target genes, adipose differentiation-related protein and mitochondrial 3-hydroxy-3-methylglutaryl coenzyme A synthase 2. This work lends support for the rational development of peptidomimetics that block receptor-mediated transcription by targeting the nuclear receptor-coactivator interaction surface.

scholarly journals PRIC295, a Nuclear Receptor Coactivator, Identified from PPAR-Interacting Cofactor Complex

PPAR Research ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Sean R. Pyper ◽  
Navin Viswakarma ◽  
Yuzhi Jia ◽  
Yi-Jun Zhu ◽  
Joseph D. Fondell ◽  
...  
Keyword(s):  
Nuclear Receptor ◽  
Target Genes ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Nuclear Receptor Coactivator ◽  
Evolutionarily Conserved

The peroxisome proliferator-activated receptor- (PPAR) plays a key role in lipid metabolism and energy combustion. Chronic activation of PPAR in rodents leads to the development of hepatocellular carcinomas. The ability of PPAR to induce expression of its target genes depends on Mediator, an evolutionarily conserved complex of cofactors and, in particular, the subunit 1 (Med1) of this complex. Here, we report the identification and characterization of PPAR-interacting cofactor (PRIC)-295 (PRIC295), a novel coactivator protein, and show that it interacts with the Med1 and Med24 subunits of the Mediator complex. PRIC295 contains 10 LXXLL signature motifs that facilitate nuclear receptor binding and interacts with PPAR and five other members of the nuclear receptor superfamily in a ligand-dependent manner. PRIC295 enhances the transactivation function of PPAR, PPAR, and ER. These data demonstrate that PRIC295 interacts with nuclear receptors such as PPAR and functions as a transcription coactivator underin vitroconditions and may play an important role in mediating the effectsin vivoas a member of the PRIC complex with Med1 and Med24.

scholarly journals A Retrospective on Nuclear Receptor Regulation of Inflammation: Lessons from GR and PPARs

PPAR Research ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Min-Dian Li ◽  
Xiaoyong Yang
Keyword(s):  
Glucocorticoid Receptor ◽  
Signaling Pathways ◽  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Receptor Regulation ◽  
Peroxisome Proliferator ◽  
Novel Therapies ◽  
Nuclear Receptor Superfamily ◽  
Founding Member ◽  
Peroxisome Proliferator Activated Receptors

Members of the nuclear receptor superfamily have vital roles in regulating immunity and inflammation. The founding member, glucocorticoid receptor (GR), is the prototype to demonstrate immunomodulation via transrepression of the AP-1 and NF-κB signaling pathways. Peroxisome proliferator-activated receptors (PPARs) have emerged as key regulators of inflammation. This review examines the history and current advances in nuclear receptor regulation of inflammation by the crosstalk with AP-1 and NF-κB signaling, focusing on the roles of GR and PPARs. A better understanding of the molecular mechanism by which nuclear receptors inhibit proinflammatory signaling pathways will enable novel therapies to treat chronic inflammation.

P1941The nuclear receptor corepressor 1 blocks CD36-mediated foam cell formation in atherogenesis

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S Oppi ◽  
S Stein ◽  
V Marzolla ◽  
E Osto ◽  
Z Rancic ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Target Genes ◽  
Foam Cell ◽  
Foam Cell Formation ◽  
High Cholesterol Diet ◽  
Peroxisome Proliferator ◽  
Aortic Sinus ◽  
Protective Function ◽  
Nuclear Receptor Corepressor

Abstract Background Nuclear receptors and their cofactors regulate the expression of various target genes in different tissue and organs to orchestrate downstream (patho)physiological processes. Although the function of several nuclear receptors in atherosclerosis has been studied, very little is known about the role of nuclear receptor cofactors in atherosclerosis. Given its important role to suppress inflammatory processes, we speculated that macrophage nuclear receptor corepressor 1 (NCOR1) plays a protective function in atherosclerosis development. Purpose To evaluate the contribution of macrophage NCOR1 in atherosclerosis we used myeloid cell-specific Ncor1 knockout mice on an atherosclerosis-prone background. Methods and results 8-week-old male and female mice were exposed to a high high-cholesterol diet for 12 weeks. Our findings demonstrate that the lack of macrophage Ncor1 leads to a severe atherosclerotic phenotype in both sexes. These mice show a higher content of plaques along the thoraco-abdominal aortae as well as at the aortic sinus, which were characterized by larger necrotic cores and thinner fibrous caps, a typical signature of unstable plaques. Moreover, we found that the pro-atherogenic effects of the Ncor1 deletion are mediated via derepression of peroxisome proliferator-activated receptor gamma (PPARγ) target genes in mouse and human macrophages, especially the enhanced expression of the CD36 scavenger receptor and the subsequent rise in oxLDL uptake. Interestingly, while the expression of NCOR1 is reduced, the PPARγ signature is increased in human atherosclerotic plaques, and this signature is further pronounced in ruptured compared to stable carotid plaques. Conclusion Our findings suggest that macrophage NCOR1 blocks the pro-atherogenic functions of PPARγ in atherosclerosis and prevents the disease development. Acknowledgement/Funding The Swiss National Science Foundation, the Novartis Foundation, Olga-Mayenfisch Foundation, the OPO foundation

The metabolic coregulator RIP140: an update

2010 ◽  
Vol 299 (3) ◽  
pp. E335-E340 ◽  
Author(s):  
Asmaà Fritah ◽  
Mark Christian ◽  
Malcolm G. Parker
Keyword(s):  
Nuclear Receptors ◽  
Posttranslational Modifications ◽  
Energy Homeostasis ◽  
Target Genes ◽  
Peroxisome Proliferator ◽  
Transcriptional Coregulator ◽  
Peroxisome Proliferator Activated Receptors ◽  
Direct Regulation

RIP140 is a transcriptional coregulator highly expressed in metabolic tissues where it has important and diverse actions. RIP140-null mice show that it plays a crucial role in the control of lipid metabolism in adipose tissue, skeletal muscle, and the liver and is essential for female fertility. RIP140 has been shown to act as a ligand-dependent transcriptional corepressor for metabolic nuclear receptors such as estrogen-related receptors and peroxisome proliferator-activated receptors. The role of RIP140 as a corepressor has been strengthened by the characterization of RIP140-overexpressing mice, although it emerges through several studies that RIP140 can also behave as a coactivator. Nuclear localization of RIP140 is important for controlling transcription of target genes and is subject to regulation by posttranslational modifications. However, cytoplasmic RIP140 has been shown to play a role in the control of metabolism through direct regulation of glucose transport in adipocytes. In this review, we focus on recent advances highlighting the growing importance of RIP140 as a regulator of energy homeostasis.

How nuclear receptors tell time

2009 ◽  
Vol 107 (6) ◽  
pp. 1965-1971 ◽  
Author(s):  
Michèle Teboul ◽  
Aline Gréchez-Cassiau ◽  
Fabienne Guillaumond ◽  
Franck Delaunay
Keyword(s):  
Nuclear Receptors ◽  
Target Genes ◽  
Clock Genes ◽  
Estrogen Receptor Α ◽  
Nuclear Hormone Receptor ◽  
Circadian Clocks ◽  
Orphan Receptor ◽  
Peroxisome Proliferator ◽  
Peripheral Clocks ◽  
Peroxisome Proliferator Activated Receptors

Most organisms adapt their behavior and physiology to the daily changes in their environment through internal (∼24 h) circadian clocks. In mammals, this time-keeping system is organized hierarchically, with a master clock located in the suprachiasmatic nuclei of the hypothalamus that is reset by light, and that, in turn, coordinates the oscillation of local clocks found in all cells. Central and peripheral clocks control, in a highly tissue-specific manner, hundreds of target genes, resulting in the circadian regulation of most physiological processes. A great deal of knowledge has accumulated during the last decade regarding the molecular basis of mammalian circadian clocks. These studies have collectively demonstrated how a set of clock genes and their protein products interact together in complex feedback transcriptional/translational loops to generate 24-h oscillations at the molecular, cellular, and organism levels. In recent years, a number of nuclear receptors (NRs) have been implicated as important regulators of the mammalian clock mechanism. REV-ERB and retinoid-related orphan receptor NRs regulate directly the core feedback loop and increase its robustness. The glucocorticoid receptor mediates the synchronizing effect of glucocorticoid hormones on peripheral clocks. Other NR family members, including the orphan NR EAR2, peroxisome proliferator activated receptors-α/γ, estrogen receptor-α, and retinoic acid receptors, are also linked to the clockwork mechanism. These findings together establish nuclear hormone receptor signaling as an integral part of the circadian timing system.

scholarly journals Peroxisome proliferator-activated receptors and retinoic acid receptors differentially control the interactions of retinoid X receptor heterodimers with ligands, coactivators, and corepressors.

1997 ◽  
Vol 17 (4) ◽  
pp. 2166-2176 ◽  
Author(s):  
J DiRenzo ◽  
M Söderstrom ◽  
R Kurokawa ◽  
M H Ogliastro ◽  
M Ricote ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Nuclear Receptor ◽  
Target Genes ◽  
Direct Repeat ◽  
Retinoic Acid Receptors ◽  
Structural Motif ◽  
Peroxisome Proliferator ◽  
Response Elements ◽  
Peroxisome Proliferator Activated Receptors

As the obligate member of most nuclear receptor heterodimers, retinoid X receptors (RXRs) can potentially perform two functions: cooperative binding to hormone response elements and coordinate regulation of target genes by RXR ligands. In this paper we describe allosteric interactions between RXR and two heterodimeric partners, retinoic acid receptors (RARs) and peroxisome proliferator-activated receptors (PPARs); RARs and PPARs prevent and permit activation by RXR-specific ligands, respectively. By competing for dimerization with RXR on response elements consisting of direct-repeat half-sites spaced by 1 bp (DR1 elements), the relative abundance of RAR and PPAR determines whether the RXR signaling pathway will be functional. In contrast to RAR, which prevents the binding of RXR ligands and recruits the nuclear receptor corepressor N-CoR, PPAR permits the binding of SRC-1 in response to both RXR and PPAR ligands. Overexpression of SRC-1 markedly potentiates ligand-dependent transcription by PPARgamma, suggesting that SRC-1 serves as a coactivator in vivo. Remarkably, the ability of RAR to both block the binding of ligands to RXR and interact with corepressors requires the CoR box, a structural motif residing in the N-terminal region of the RAR ligand binding domain. Mutations in the CoR box convert RAR from a nonpermissive to a permissive partner of RXR signaling on DR1 elements. We suggest that the differential recruitment of coactivators and corepressors by RAR-RXR and PPAR-RXR heterodimers provides the basis for a transcriptional switch that may be important in controlling complex programs of gene expression, such as adipocyte differentiation.

scholarly journals PPARs Integrate the Mammalian Clock and Energy Metabolism

PPAR Research ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Lihong Chen ◽  
Guangrui Yang
Keyword(s):  
Energy Metabolism ◽  
Nuclear Receptors ◽  
Essential Role ◽  
Target Gene ◽  
Target Genes ◽  
Circadian Regulation ◽  
Peroxisome Proliferator ◽  
Mouse Tissues ◽  
Peroxisome Proliferator Activated Receptors

Peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptors that function as transcription factors regulating the expression of numerous target genes. PPARs play an essential role in various physiological and pathological processes, especially in energy metabolism. It has long been known that metabolism and circadian clocks are tightly intertwined. However, the mechanism of how they influence each other is not fully understood. Recently, all three PPAR isoforms were found to be rhythmically expressed in given mouse tissues. Among them, PPARαand PPARγare direct regulators of core clock components, Bmal1 and Rev-erbα, and, conversely, PPARαis also a direct Bmal1 target gene. More importantly, recent studies using knockout mice revealed that all PPARs exert given functions in a circadian manner. These findings demonstrated a novel role of PPARs as regulators in correlating circadian rhythm and metabolism. In this review, we summarize advances in our understanding of PPARs in circadian regulation.

scholarly journals The Endocannabinoid System and PPARs: Focus on Their Signalling Crosstalk, Action and Transcriptional Regulation

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 586
Author(s):  
Fabio Arturo Iannotti ◽  
Rosa Maria Vitale
Keyword(s):  
Nuclear Receptors ◽  
Target Genes ◽  
Immune Reaction ◽  
Endocannabinoid System ◽  
Peroxisome Proliferator ◽  
Adaptive Responses ◽  
Reaction Cell ◽  
Reciprocal Regulation ◽  
Exogenous Lipid ◽  
Peroxisome Proliferator Activated Receptors

Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear receptors including PPARα, PPARγ, and PPARβ/δ, acting as transcription factors to regulate the expression of a plethora of target genes involved in metabolism, immune reaction, cell differentiation, and a variety of other cellular changes and adaptive responses. PPARs are activated by a large number of both endogenous and exogenous lipid molecules, including phyto- and endo-cannabinoids, as well as endocannabinoid-like compounds. In this view, they can be considered an extension of the endocannabinoid system. Besides being directly activated by cannabinoids, PPARs are also indirectly modulated by receptors and enzymes regulating the activity and metabolism of endocannabinoids, and, vice versa, the expression of these receptors and enzymes may be regulated by PPARs. In this review, we provide an overview of the crosstalk between cannabinoids and PPARs, and the importance of their reciprocal regulation and modulation by common ligands, including those belonging to the extended endocannabinoid system (or “endocannabinoidome”) in the control of major physiological and pathophysiological functions.

scholarly journals Inactivation of the Nuclear Receptor Coactivator RAP250 in Mice Results in Placental Vascular Dysfunction

2003 ◽  
Vol 23 (4) ◽  
pp. 1260-1268 ◽  
Author(s):  
Per Antonson ◽  
Gertrud U. Schuster ◽  
Ling Wang ◽  
Björn Rozell ◽  
Elin Holter ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Blood Circulation ◽  
Transcriptional Activity ◽  
Vascular Dysfunction ◽  
Diverse Group ◽  
Placental Development ◽  
Nuclear Receptor Coactivator ◽  
The Past ◽  
Placental Blood

ABSTRACT Coactivators constitute a diverse group of proteins that are essential for optimal transcriptional activity of nuclear receptors. In the past few years many coactivators have been identified but it is still unclear whether these proteins interact indiscriminately with all nuclear receptors and whether there is some redundancy in their functions. We have previously cloned and characterized RAP250 (ASC-2/PRIP/TRBP/NRC), an LXXLL-containing coactivator for nuclear receptors. In order to study its biological role, Rap250 null mice were generated by gene targeting. Here we show that genetic disruption of Rap250 results in embryonic lethality at embryonic day (E) 13.5. Histological examination of placentas revealed a dramatically reduced spongiotrophoblast layer, a collapse of blood vessels in the region bordering the spongiotrophoblast, and labyrinthine layers in placentas from Rap250−/− embryos. These findings suggest that the lethality of Rap250−/− embryos is the result of obstructed placental blood circulation. Moreover, the transcriptional activity of PPARγ is reduced in fibroblasts derived from Rap250−/− embryos, suggesting that RAP250 is an essential coactivator for this nuclear receptor in the placenta. Our results demonstrate that RAP250 is necessary for placental development and thus essential for embryonic development.

scholarly journals PPARgene: A Database of Experimentally Verified and Computationally Predicted PPAR Target Genes

PPAR Research ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Li Fang ◽  
Man Zhang ◽  
Yanhui Li ◽  
Yan Liu ◽  
Qinghua Cui ◽  
...  
Keyword(s):  
In Silico ◽  
Target Gene ◽  
Target Genes ◽  
Prediction Method ◽  
Peroxisome Proliferator ◽  
Physiological Processes ◽  
Peroxisome Proliferator Activated Receptors ◽  
High Throughput Gene Expression ◽  
Responsive Element ◽  
Target Gene Transcription

The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors of the nuclear receptor superfamily. Upon ligand binding, PPARs activate target gene transcription and regulate a variety of important physiological processes such as lipid metabolism, inflammation, and wound healing. Here, we describe the first database of PPAR target genes, PPARgene. Among the 225 experimentally verified PPAR target genes, 83 are for PPARα, 83 are for PPARβ/δ, and 104 are for PPARγ. Detailed information including tissue types, species, and reference PubMed IDs was also provided. In addition, we developed a machine learning method to predict novel PPAR target genes by integratingin silicoPPAR-responsive element (PPRE) analysis with high throughput gene expression data. Fivefold cross validation showed that the performance of this prediction method was significantly improved compared to thein silicoPPRE analysis method. The prediction tool is also implemented in the PPARgene database.

Sign in / Sign up

Export Citation Format

Share Document