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Park SJ, Kwon W, Park S, Jeong J, Kim D, Jang S, Kim SY, Sung Y, Kim MO, Choi SK, Ryoo ZY. Jazf1 acts as a regulator of insulin-producing β-cell differentiation in induced pluripotent stem cells and glucose homeostasis in mice. FEBS J 2021; 288:4412-4427. [PMID: 33555104 DOI: 10.1111/febs.15751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 12/02/2020] [Accepted: 02/04/2021] [Indexed: 12/13/2022]
Abstract
Genetic susceptibility of type 2 diabetes and Juxtaposed with another zinc finger protein 1 (Jazf1) has been reported; however, the precise role of Jazf1 in metabolic processes remains elusive. In this study, using Jazf1-knockout (KO)-induced pluripotent stem cells (iPSC), pancreatic beta cell line MIN6 cells, and Jazf-1 heterozygous KO (Jazf1+/- ) mice, the effect of Jazf1 on gradual differentiation was investigated. We checked the alterations of the genes related with β-cell specification, maturation, and insulin release against glucose treatment by the gain and loss of the Jazf1 gene in the MIN6 cells. Because undifferentiated Jazf1-KO iPSC were not significantly different from wild-type (WT) iPSC, the size and endoderm marker expression after embryoid body (EB) and teratoma formation were investigated. Compared to EB and teratomas formed with WT iPSC, the EB and teratomas from with Jazf1-KO iPSC were smaller, and in teratomas, the expression of proliferation markers was reduced. Moreover, the expression of the gene sets for β-cell differentiation and the levels of insulin and C-peptide secreted by insulin precursor cells were notably reduced in β-cells differentiated from Jazf1-KO iPSC compared with those differentiated from WT iPSC. A comparison of Jazf1+/- and WT mice showed that Jazf1+/- mice had lower levels of serum insulin, pancreatic insulin expression, and decreased pancreatic β-cell size, which resulted in defects in the glucose homeostasis. These findings suggest that Jazf1 plays a pivotal role in the differentiation of β-cells and glucose homeostasis.
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Affiliation(s)
- Si Jun Park
- School of Life Science, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea.,Institute of Life Science and Biotechnology, Kyungpook National University, Daegu, Korea
| | - Wookbong Kwon
- School of Life Science, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea.,Division of Biotechnology, DGIST, Daegu, Korea
| | - Song Park
- Core Protein Resources Center, DGIST, Daegu, Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Korea
| | - Jain Jeong
- Core Protein Resources Center, DGIST, Daegu, Korea.,Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Dongjun Kim
- School of Life Science, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
| | - Soyoung Jang
- School of Life Science, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
| | - Si-Yong Kim
- School of Life Science, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
| | - Yonghun Sung
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea
| | - Myoung Ok Kim
- Department of Animal Science and Biotechnology, Kyungpook National University, Sangju, Korea
| | - Seong-Kyoon Choi
- Division of Biotechnology, DGIST, Daegu, Korea.,Core Protein Resources Center, DGIST, Daegu, Korea
| | - Zae Young Ryoo
- School of Life Science, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
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Sakamoto T, Matsuura TR, Wan S, Ryba DM, Kim J, Won KJ, Lai L, Petucci C, Petrenko N, Musunuru K, Vega RB, Kelly DP. A Critical Role for Estrogen-Related Receptor Signaling in Cardiac Maturation. Circ Res 2020; 126:1685-1702. [PMID: 32212902 PMCID: PMC7274895 DOI: 10.1161/circresaha.119.316100] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RATIONALE The heart undergoes dramatic developmental changes during the prenatal to postnatal transition, including maturation of cardiac myocyte energy metabolic and contractile machinery. Delineation of the mechanisms involved in cardiac postnatal development could provide new insight into the fetal shifts that occur in the diseased heart and unveil strategies for driving maturation of stem cell-derived cardiac myocytes. OBJECTIVE To delineate transcriptional drivers of cardiac maturation. METHODS AND RESULTS We hypothesized that ERR (estrogen-related receptor) α and γ, known transcriptional regulators of postnatal mitochondrial biogenesis and function, serve a role in the broader cardiac maturation program. We devised a strategy to knockdown the expression of ERRα and γ in heart after birth (pn-csERRα/γ [postnatal cardiac-specific ERRα/γ]) in mice. With high levels of knockdown, pn-csERRα/γ knockdown mice exhibited cardiomyopathy with an arrest in mitochondrial maturation. RNA sequence analysis of pn-csERRα/γ knockdown hearts at 5 weeks of age combined with chromatin immunoprecipitation with deep sequencing and functional characterization conducted in human induced pluripotent stem cell-derived cardiac myocytes (hiPSC-CM) demonstrated that ERRγ activates transcription of genes involved in virtually all aspects of postnatal developmental maturation, including mitochondrial energy transduction, contractile function, and ion transport. In addition, ERRγ was found to suppress genes involved in fibroblast activation in hearts of pn-csERRα/γ knockdown mice. Disruption of Esrra and Esrrg in mice during fetal development resulted in perinatal lethality associated with structural and genomic evidence of an arrest in cardiac maturation, including persistent expression of early developmental and noncardiac lineage gene markers including cardiac fibroblast signatures. Lastly, targeted deletion of ESRRA and ESRRG in hiPSC-CM derepressed expression of early (transcription factor 21 or TCF21) and mature (periostin, collagen type III) fibroblast gene signatures. CONCLUSIONS ERRα and γ are critical regulators of cardiac myocyte maturation, serving as transcriptional activators of adult cardiac metabolic and structural genes, an.d suppressors of noncardiac lineages including fibroblast determination.
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Affiliation(s)
| | | | - Shibiao Wan
- Institute for Diabetes, Obesity and Metabolism, Dept. Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Center for Applied Bioinformatics, St. Jude Children’s Research Hospital, Memphis, TN 38105
| | | | - Junil Kim
- Institute for Diabetes, Obesity and Metabolism, Dept. Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Kyoung Jae Won
- Institute for Diabetes, Obesity and Metabolism, Dept. Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | - Rick B. Vega
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida, 32827, USA
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Abstract
Testicular nuclear receptors 2 and 4 (TR2, TR4), also known as NR2C1 and NR2C2, belong to the nuclear receptor superfamily and were first cloned in 1989 and 1994, respectively. Although classified as orphan receptors, several natural molecules, their metabolites, and synthetic compounds including polyunsaturated fatty acids (PUFAs), PUFA metabolites 13-hydroxyoctadecadienoic acid, 15-hydroxyeicosatetraenoic acid, and the antidiabetic drug thiazolidinediones can transactivate TR4. Importantly, many of these ligands/activators can also transactivate peroxisome proliferator-activated receptor gamma (PPARγ), also known as NR1C3 nuclear receptor. Both TR4 and PPARγ can bind to similar hormone response elements (HREs) located in the promoter of their common downstream target genes. However, these two nuclear receptors, even with shared ligands/activators and shared binding ability for similar HREs, have some distinct functions in many diseases they influence. In cancer, PPARγ inhibits thyroid, lung, colon, and prostate cancers but enhances bladder cancer. In contrast, TR4 inhibits liver and prostate cancer initiation but enhances pituitary corticotroph, liver, and prostate cancer progression. In type 2 diabetes, PPARγ increases insulin sensitivity but TR4 decreases insulin sensitivity. In cardiovascular disease, PPARγ inhibits atherosclerosis but TR4 enhances atherosclerosis through increasing foam cell formation. In bone physiology, PPARγ inhibits bone formation but TR4 increases bone formation. Together, the contrasting impact of TR4 and PPARγ on different diseases may raise a critical issue about drug used to target any one of these nuclear receptors.
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Olivares AM, Moreno-Ramos OA, Haider NB. Role of Nuclear Receptors in Central Nervous System Development and Associated Diseases. J Exp Neurosci 2016; 9:93-121. [PMID: 27168725 PMCID: PMC4859451 DOI: 10.4137/jen.s25480] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 11/13/2022] Open
Abstract
The nuclear hormone receptor (NHR) superfamily is composed of a wide range of receptors involved in a myriad of important biological processes, including development, growth, metabolism, and maintenance. Regulation of such wide variety of functions requires a complex system of gene regulation that includes interaction with transcription factors, chromatin-modifying complex, and the proper recognition of ligands. NHRs are able to coordinate the expression of genes in numerous pathways simultaneously. This review focuses on the role of nuclear receptors in the central nervous system and, in particular, their role in regulating the proper development and function of the brain and the eye. In addition, the review highlights the impact of mutations in NHRs on a spectrum of human diseases from autism to retinal degeneration.
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Affiliation(s)
- Ana Maria Olivares
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Oscar Andrés Moreno-Ramos
- Departamento de Ciencias Biológicas, Facultad de Ciencias, Universidad de los Andes, Bogotá, Colombia
| | - Neena B Haider
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
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Zhi X, Zhou XE, Melcher K, Xu HE. Structures and regulation of non-X orphan nuclear receptors: A retinoid hypothesis. J Steroid Biochem Mol Biol 2016; 157:27-40. [PMID: 26159912 DOI: 10.1016/j.jsbmb.2015.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 06/10/2015] [Accepted: 06/16/2015] [Indexed: 12/28/2022]
Abstract
Nuclear receptors are defined as a family of ligand regulated transcription factors [1-6]. While this definition reflects that ligand binding is a key property of nuclear receptors, it is still a heated subject of debate if all the nuclear receptors (48 human members) can bind ligands (ligands referred here to both physiological and synthetic ligands). Recent studies in nuclear receptor structure biology and pharmacology have undoubtedly increased our knowledge of nuclear receptor functions and their regulation. As a result, they point to new avenues for the discovery and development of nuclear receptor regulators, including nuclear receptor ligands. Here we review the recent literature on orphan nuclear receptor structural analysis and ligand identification, particularly on the orphan nuclear receptors that do not heterodimerize with retinoid X receptors, which we term as non-X orphan receptors. We also propose a speculative "retinoid hypothesis" for a subset of non-X orphan nuclear receptors, which we hope to help shed light on orphan nuclear receptor biology and drug discovery. This article is part of a Special Issue entitled 'Orphan Nuclear Receptors'.
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Affiliation(s)
- Xiaoyong Zhi
- Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503, USA; Autophagy Research Center, University of Texas Southwestern Medical Center, 6000Harry Hines Blvd., Dallas, TX 75390, USA.
| | - X Edward Zhou
- Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503, USA
| | - Karsten Melcher
- Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503, USA
| | - H Eric Xu
- Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503, USA; VARI-SIMM Center, Key Laboratory of Receptor Research, Shanghai Institute of MateriaMedica, Chinese Academy of Sciences, Shanghai 201203, China.
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Yuasa K, Aoki N, Hijikata T. JAZF1 promotes proliferation of C2C12 cells, but retards their myogenic differentiation through transcriptional repression of MEF2C and MRF4-Implications for the role of Jazf1 variants in oncogenesis and type 2 diabetes. Exp Cell Res 2015; 336:287-97. [PMID: 26101156 DOI: 10.1016/j.yexcr.2015.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/09/2015] [Accepted: 06/15/2015] [Indexed: 11/16/2022]
Abstract
Single-nucleotide polymorphisms associated with type 2 diabetes (T2D) have been identified in Jazf1, which is also involved in the oncogenesis of endometrial stromal tumors. To understand how Jazf1 variants confer a risk of tumorigenesis and T2D, we explored the functional roles of JAZF1 and searched for JAZF1 target genes in myogenic C2C12 cells. Consistent with an increase of Jazf1 transcripts during myoblast proliferation and their decrease during myogenic differentiation in regenerating skeletal muscle, JAZF1 overexpression promoted cell proliferation, whereas it retarded myogenic differentiation. Examination of myogenic genes revealed that JAZF1 overexpression transcriptionally repressed MEF2C and MRF4 and their downstream genes. AMP deaminase1 (AMPD1) was identified as a candidate for JAZF1 target by gene array analysis. However, promoter assays of Ampd1 demonstrated that mutation of the putative binding site for the TR4/JAZF1 complex did not alleviate the repressive effects of JAZF1 on promoter activity. Instead, JAZF1-mediated repression of Ampd1 occurred through the MEF2-binding site and E-box within the Ampd1 proximal regulatory elements. Consistently, MEF2C and MRF4 expression enhanced Ampd1 promoter activity. AMPD1 overexpression and JAZF1 downregulation impaired AMPK phosphorylation, while JAZF1 overexpression also reduced it. Collectively, these results suggest that aberrant JAZF1 expression contributes to the oncogenesis and T2D pathogenesis.
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Affiliation(s)
- Katsutoshi Yuasa
- Department of Anatomy and Cell Biology, Research Institute of Pharmaceutical Science, Faculty of Pharmacy, Musashino University, Nishitokyo, Tokyo 202-8585, Japan
| | - Natsumi Aoki
- Department of Anatomy and Cell Biology, Research Institute of Pharmaceutical Science, Faculty of Pharmacy, Musashino University, Nishitokyo, Tokyo 202-8585, Japan
| | - Takao Hijikata
- Department of Anatomy and Cell Biology, Research Institute of Pharmaceutical Science, Faculty of Pharmacy, Musashino University, Nishitokyo, Tokyo 202-8585, Japan.
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Yang O, Kim HL, Weon JI, Seo YR. Endocrine-disrupting Chemicals: Review of Toxicological Mechanisms Using Molecular Pathway Analysis. J Cancer Prev 2015; 20:12-24. [PMID: 25853100 PMCID: PMC4384711 DOI: 10.15430/jcp.2015.20.1.12] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/14/2015] [Indexed: 01/12/2023] Open
Abstract
Endocrine disruptors are known to cause harmful effects to human through various exposure routes. These chemicals mainly appear to interfere with the endocrine or hormone systems. As importantly, numerous studies have demonstrated that the accumulation of endocrine disruptors can induce fatal disorders including obesity and cancer. Using diverse biological tools, the potential molecular mechanisms related with these diseases by exposure of endocrine disruptors. Recently, pathway analysis, a bioinformatics tool, is being widely used to predict the potential mechanism or biological network of certain chemicals. In this review, we initially summarize the major molecular mechanisms involved in the induction of the above mentioned diseases by endocrine disruptors. Additionally, we provide the potential markers and signaling mechanisms discovered via pathway analysis under exposure to representative endocrine disruptors, bisphenol, diethylhexylphthalate, and nonylphenol. The review emphasizes the importance of pathway analysis using bioinformatics to finding the specific mechanisms of toxic chemicals, including endocrine disruptors.
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Affiliation(s)
- Oneyeol Yang
- Department of Life Science, College of Life Sciences and Biotechnology, Dongguk University Biomedi Campus, Goyang ; Institute of Environmental Medicine, Dongguk University Biomedi Campus, Seoul
| | - Hye Lim Kim
- Department of Life Science, College of Life Sciences and Biotechnology, Dongguk University Biomedi Campus, Goyang ; Institute of Environmental Medicine, Dongguk University Biomedi Campus, Seoul
| | - Jong-Il Weon
- Institute of Environmental Medicine, Dongguk University Biomedi Campus, Seoul ; Department of Safety Engineering, Dongguk University College of Natural Science, Gyeongju, Korea
| | - Young Rok Seo
- Department of Life Science, College of Life Sciences and Biotechnology, Dongguk University Biomedi Campus, Goyang ; Institute of Environmental Medicine, Dongguk University Biomedi Campus, Seoul
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Wang Y, Li C, Wang Q, Shi T, Wang J, Chen H, Wu Y, Han J, Guo S, Wang Y, Wang W. Danqi Pill regulates lipid metabolism disorder induced by myocardial ischemia through FATP-CPTI pathway. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 15:28. [PMID: 25885422 PMCID: PMC4355010 DOI: 10.1186/s12906-015-0548-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 02/12/2015] [Indexed: 12/31/2022]
Abstract
Background Danqi Pill (DQP), which contains Chinese herbs Salvia miltiorrhiza Bunge and Panax notoginseng, is widely used in the treatment of myocardial ischemia (MI) in China. Its regulatory effects on MI-associated lipid metabolism disorders haven’t been comprehensively studied so far. We aimed to systematically investigate the regulatory mechanism of DQP on myocardial ischemia-induced lipid metabolism disorders. Methods Myocardial ischemia rat model was induced by left anterior descending coronary artery ligation. The rat models were divided into three groups: model group with administration of normal saline, study group with administration of DanQi aqueous solution (1.5 mg/kg) and positive-control group with administration of pravastatin aqueous solution (1.2 mg/kg). In addition, another sham-operated group was set as negative control. At 28 days after treatment, cardiac function and degree of lipid metabolism disorders in rats of different groups were measured. Results Plasma lipid disorders were induced by myocardial ischemia, with manifestation of up-regulation of triglyceride (TG), low density lipoprotein (LDL), Apolipoprotein B (Apo-B) and 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGCR). DQP could down-regulate the levels of TG, LDL, Apo-B and HMGCR. The Lipid transport pathway, fatty acids transport protein (FATP) and Carnitine palmitoyltransferase I (CPTI) were down-regulated in model group. DQP could improve plasma lipid metabolism by up-regulating this lipid transport pathway. The transcription factors peroxisome proliferator-activated receptor α (PPARα) and retinoid X receptors (RXRs), which regulate lipid metabolism, were also up-regulated by DQP. Furthermore, DQP was able to improve heart function and up-regulate ejection fraction (EF) by increasing the cardiac diastolic volume. Conclusions Our study reveals that DQP would be an ideal alternative drug for the treatment of dyslipidemia which is induced by myocardial ischemia.
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Transcription factor TIP27 regulates glucose homeostasis and insulin sensitivity in a PI3-kinase/Akt-dependent manner in mice. Int J Obes (Lond) 2015; 39:949-58. [PMID: 25614086 DOI: 10.1038/ijo.2015.5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 11/26/2014] [Accepted: 11/30/2014] [Indexed: 01/09/2023]
Abstract
BACKGROUND/OBJECTIVES Juxtaposed with another zinc-finger gene 1 (TIP27 or JAZF1) is a 27-kDa transcription factor, and genome-wide association studies have recently revealed TIP27 to be associated with type 2 diabetes. However, little is known about its role in the regulation of metabolism. In this study, we investigated the effects of TIP27 overexpression on glucose homeostasis and insulin signaling in high-fat diet (HFD)-fed TIP27 transgenic (TIP27-Tg) mice and db/db mice. METHODS We assessed the effects of TIP27 overexpression in both TIP27-Tg mice and db/db mice on glucose metabolism and changes in insulin sensitivity during glucose (GTT) and insulin (ITT) tolerance tests. A hyperinsulinemic-euglycemic clamp was performed on TIP27-Tg mice. Real-time quantitative PCR and western blotting were used to assess mRNA and protein expressions. RESULTS TIP27 overexpression in TIP27-Tg mice and in db/db mice led to reduced total cholesterol and fasting plasma insulin levels, and enhanced glucose tolerance and insulin sensitivity during GTT and ITT. Hyperinsulinemic-euglycemic clamp experiments demonstrated that HFD-fed TIP27-Tg mice had lower hepatic glucose production and higher insulin sensitivity compared with nontransgenic littermates. In addition, the hepatic expressions of phosphoenolpyruate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase) mRNAs and proteins were significantly decreased, whereas the phosphorylation of insulin receptor, insulin receptor substrate-1, adenosine monophosphate-activated protein kinase and Akt kinase (Akt) in the liver was significantly increased in HFD-fed TIP27-Tg mice compared with nontransgenic littermates. Adenovirus-mediated TIP27 overexpression in db/db mice also decreased the expression of gluconeogenic genes and increased the phosphorylation of insulin signaling molecules in the liver compared with controls. Finally, LY294002, a phosphatidylinositol 3-kinase (PI3-kinase) inhibitor, abolished the suppressive effect of TIP27 overexpression on PEPCK and G6Pase expression. CONCLUSIONS TIP27 has an important role in glucose homeostasis through the regulation of hepatic glucose metabolism and insulin sensitivity. Furthermore, this regulation requires activation of PI3-kinase.
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Li X, Yang M, Wang H, Jia Y, Yan P, Boden G, Yang G, Li L. Overexpression of JAZF1 protected ApoE-deficient mice from atherosclerosis by inhibiting hepatic cholesterol synthesis via CREB-dependent mechanisms. Int J Cardiol 2014; 177:100-10. [PMID: 25499349 DOI: 10.1016/j.ijcard.2014.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 07/12/2014] [Accepted: 09/15/2014] [Indexed: 12/18/2022]
Abstract
Genome wide association studies have suggested an association of Juxtaposed with another zinc finger gene 1(JAZF1) with type 2 diabetes mellitus (T2DM). As an inhibitor of the TAK1/TR4 signaling pathway, JAZF1 has been shown to be involved in gluconeogenesis, lipid metabolism and insulin sensitivity. However, its role in insulin resistance and atherosclerosis in vivo remains unknown. The present study was designed to investigate in vivo the impact of JAZF1 on insulin resistance-associated dyslipidemia and atherosclerosis. Adenovirus-mediated JAZF1 overexpression was used to characterize the role of JAZF1 in the regulation of lipid metabolism and the development of atherosclerosis in normal chow- or HFD-fed ApoE KO mice. Insulin sensitivity was examined by EHC. Cholesterol de novo synthesis was measured by intraperitoneal [1-(14)C] acetate injection and atherosclerotic plaques were quantified by histological analysis. A dual-luciferase reporter assay was used to assess the ability of JAZF1 to regulate HMGCR transcriptional activity. JAZF1 overexpression improved HFD-induced hepatic insulin resistance in C57BL/6J mice. In HFD-fed ApoE KO mice, JAZF1 overexpression decreased serum cholesterol levels and hepatic cholesterol synthesis by inhibiting CREB-dependent HMGCR promoter transcriptional activity. Analysis of atherosclerotic lesion showed that JAZF1 overexpression had significantly reduced aortic and aortic sinus en face and cross-sectional plaque areas in HFD-fed ApoE KO mice. These data provide the first evidence for an important role of JAZF1 in increasing hepatic insulin sensitivity and preventing atherosclerosis.
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Affiliation(s)
- Xiaoqiang Li
- The Key Laboratory of Laboratory Medical Diagnostics in the Ministry of Education and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, 400016 Chongqing, China
| | - Mengliu Yang
- The Key Laboratory of Laboratory Medical Diagnostics in the Ministry of Education and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, 400016 Chongqing, China
| | - Han Wang
- The Key Laboratory of Laboratory Medical Diagnostics in the Ministry of Education and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, 400016 Chongqing, China
| | - Yanjun Jia
- Department of Endocrinology, the Second Affiliated Hospital, Chongqing Medical University, 400010 Chongqing, China
| | - Pijun Yan
- Department of Endocrinology, the Second Affiliated Hospital, Chongqing Medical University, 400010 Chongqing, China
| | - Guenther Boden
- The Division of Endocrinology/Diabetes/Metabolism and the Clinical Research Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - Gangyi Yang
- The Key Laboratory of Laboratory Medical Diagnostics in the Ministry of Education and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, 400016 Chongqing, China.
| | - Ling Li
- The Key Laboratory of Laboratory Medical Diagnostics in the Ministry of Education and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, 400016 Chongqing, China.
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Ming GF, Li X, Yin JY, Ai YH, Xu DM, Ma XH, Liu ZY, Liu HX, Zhou HH, Liu ZQ. JAZF1 regulates visfatin expression in adipocytes via PPARα and PPARβ/δ signaling. Metabolism 2014; 63:1012-21. [PMID: 24930994 DOI: 10.1016/j.metabol.2014.05.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 04/20/2014] [Accepted: 05/11/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Current whole genome-wide association study has identified the association of JAZF1 with type 2 diabetes; its close relation with glucose and lipid metabolism has also been revealed. However, to date, JAZF1 remains a relatively new gene with unknown function. MATERIALS/METHODS We constructed JAZF1 overexpression vector and synthesized JAZF1 siRNA, then transfected them into 3T3-L1 adipocytes, investigated the relationship between the regulations of JAZF1, visfatin, and other adipokines, researched the specific function of JAZF1 in glucose and lipid metabolism. RESULTS This study found that the expression of JAZF1 was gradually but significantly upregulated during the induced differentiation of 3T3-L1 preadipocytes, and that the trend of its expression was consistent with that of visfatin. Further studies indicated that JAZF1 promoted the expressions of visfatin, PPARα, and PPARβ/δ in adipocytes but simultaneously inhibited the expressions of TAK1 and PPARγ. Luciferase reporter assay revealed that JAZF1 activated the transcription of visfatin, but ChIP assay results indicated that JAZF1 did not directly bind to visfatin PPRE. Our results also showed that the JAZF1 overexpression-increased visfatin expression was abolished by the addition of PPARα antagonist GW 6471 and PPARβ/δ antagonist GSK 3787 respectively. And these results were further confirmed by the experiment with PPARα and PPARβ/δ siRNAs. Meanwhile, we also found that JAZF1 inhibited the lipid accumulation during the differentiation of 3T3-L1 into mature adipocyte. CONCLUSIONS Our results indicate that JAZF1 might firstly upregulated the expression of PPARα and PPARβ/δ, which in turn activated the transcription of visfatin. JAZF1 plays an important role in lipid metabolism and may thus provide a potential tool for the treatment of obesity and lipid metabolism disorders among other diseases.
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Affiliation(s)
- Guang-feng Ming
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008; P. R. China; Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha 410078; P. R. China; Department of critical care medicine, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Xi Li
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008; P. R. China; Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha 410078; P. R. China
| | - Ji-ye Yin
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008; P. R. China; Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha 410078; P. R. China
| | - Yu-hang Ai
- Department of critical care medicine, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Dao-miao Xu
- Department of critical care medicine, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Xin-hua Ma
- Department of critical care medicine, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Zhi-yong Liu
- Department of critical care medicine, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Hui-xia Liu
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Hong-hao Zhou
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008; P. R. China; Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha 410078; P. R. China
| | - Zhao-qian Liu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008; P. R. China; Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha 410078; P. R. China.
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Lin SJ, Zhang Y, Liu NC, Yang DR, Li G, Chang C. Minireview: Pathophysiological roles of the TR4 nuclear receptor: lessons learned from mice lacking TR4. Mol Endocrinol 2014; 28:805-21. [PMID: 24702179 DOI: 10.1210/me.2013-1422] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Testicular nuclear receptor 4 (TR4), also known as NR2C2, belongs to the nuclear receptor superfamily and shares high homology with the testicular nuclear receptor 2. The natural ligands of TR4 remained unclear until the recent discoveries of several energy/lipid sensors including the polyunsaturated fatty acid metabolites, 13-hydroxyoctadecadienoic acid and 15-hydroxyeicosatetraenoic acid, and their synthetic ligands, thiazolidinediones, used for treatment of diabetes. TR4 is widely expressed throughout the body and particularly concentrated in the testis, prostate, cerebellum, and hippocampus. It has been shown to play important roles in cerebellar development, forebrain myelination, folliculogenesis, gluconeogenesis, lipogenesis, muscle development, bone development, and prostate cancer progression. Here we provide a comprehensive summary of TR4 signaling including its upstream ligands/activators/suppressors, transcriptional coactivators/repressors, downstream targets, and their in vivo functions with potential impacts on TR4-related diseases. Importantly, TR4 shares similar ligands/activators with another key nuclear receptor, peroxisome proliferator-activated receptor γ, which raised several interesting questions about how these 2 nuclear receptors may collaborate with or counteract each other's function in their related diseases. Clear dissection of such molecular mechanisms and their differential roles in various diseases may help researchers to design new potential drugs with better efficacy and fewer side effects to battle TR4 and peroxisome proliferator-activated receptor γ involved diseases.
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Affiliation(s)
- Shin-Jen Lin
- George Whipple Laboratory for Cancer Research (S.-J.L., Y.Z., N.-C.L., C.C.), Departments of Pathology, Urology, Radiation Oncology, and The Wilmot Cancer Center. University of Rochester Medical Center, Rochester, New York 14646; Department of Urology (D.-R.Y.), the Second Affiliated Hospital of Suzhou University, Suzhou, 215004 China; Chawnshang Chang Liver Cancer Center and Department of Urology (G.L.), Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310016 China; and Sex Hormone Research Center (C.C.), China Medical University/Hospital, Taichung, 404 Taiwan
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Ming GF, Xiao D, Gong WJ, Liu HX, Liu J, Zhou HH, Liu ZQ. JAZF1 can regulate the expression of lipid metabolic genes and inhibit lipid accumulation in adipocytes. Biochem Biophys Res Commun 2014; 445:673-80. [PMID: 24583129 DOI: 10.1016/j.bbrc.2014.02.088] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 02/20/2014] [Indexed: 01/15/2023]
Abstract
JAZF1 is a newly identified gene with unknown functions. A recent genome-wide association study showed that JAZF1 is associated with type 2 diabetes and is highly expressed in liver and adipose tissue. Studies have demonstrated that JAZF1 is the co-repressor for nuclear orphan receptor TAK1, whereas most nuclear orphan receptor family members are involved in the regulation of lipid metabolism. Therefore, JAZF1 could be closely related to glycolipid metabolism. In this study, JAZF1 was significantly upregulated during the induced differentiation process of 3T3-L1 preadipocytes. The overexpression of JAZF1 inhibited lipid accumulation in differentiated mature 3T3-L1 adipocytes and significantly inhibited the expression of SREBPl, ACC, and FAS, which were important in lipid synthesis, while upregulating the expression of key enzyme hormone-sensitive lipase in lipoclasis. Moreover, SREBPl exhibited an inhibitory function on the expression of JAZF1. SREBP1 reversed the inhibitory action on lipid accumulation of JAZF1. SREBP1 and JAZF1 were observed to regulate each other in adipocytes. Therefore, JAZF1 could regulate the expression of particular genes related to lipid metabolism and inhibit lipid accumulation in adipocytes. This result suggests that JAZF1 may be a potential target for the treatment of diseases, such as obesity and lipid metabolism disorders.
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Affiliation(s)
- Guang-feng Ming
- Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China; Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Di Xiao
- Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Wei-jing Gong
- Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Hui-xia Liu
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Jun Liu
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Hong-hao Zhou
- Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China
| | - Zhao-qian Liu
- Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, Hunan, China.
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Simandi Z, Cuaranta-Monroy I, Nagy L. Nuclear receptors as regulators of stem cell and cancer stem cell metabolism. Semin Cell Dev Biol 2013; 24:716-23. [DOI: 10.1016/j.semcdb.2013.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
The nuclear receptor superfamily includes many receptors, identified based on their similarity to steroid hormone receptors but without a known ligand. The study of how these receptors are diversely regulated to interact with genomic regions to control a plethora of biological processes has provided critical insight into development, physiology, and the molecular pathology of disease. Here we provide a compendium of these so-called orphan receptors and focus on what has been learned about their modes of action, physiological functions, and therapeutic promise.
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Affiliation(s)
- Shannon E Mullican
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Ding XF, Yu SC, Chen BD, Lin SJ, Chang C, Li GH. Recent advances in the study of testicular nuclear receptor 4. J Zhejiang Univ Sci B 2013; 14:171-7. [PMID: 23463759 DOI: 10.1631/jzus.b1200357] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Testicular nuclear receptor 4 (TR4), also known as NR2C2 (nuclear receptor subfamily 2, group C, member 2), is a transcriptional factor and a member of the nuclear receptor family. TR4 was initially cloned from human and rat hypothalamus, prostate, and testes libraries. For almost two decades, its specific tissue distribution, genomic organization, and chromosomal assignment have been well investigated in humans and animals. However, it has been very difficult to study TR4's physiological functions due to a lack of specific ligands. Gene knock-out animal techniques provide an alternative approach for defining the biological functions of TR4. In vivo studies of TR4 gene knockout mice (TR4(-/-)) found that they display severe spinal curvature, subfertility, premature aging, and prostate prostatic intraepithelial neoplasia (PIN) development. Upstream modulators, downstream target gene regulation, feedback mechanisms, and differential modulation mediated by the recruitment of other nuclear receptors and coregulators have been identified in studies using the TR4(-/-) phenotype. With the establishment of a tissue-specific TR4(-/-) mouse model, research on TR4 will be more convenient in the future.
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Affiliation(s)
- Xian-fan Ding
- Department of Urology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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Shin SS, Yoon M. The herbal composition GGEx18 from Laminaria japonica, Rheum palmatum, and Ephedra sinica inhibits high-fat diet-induced hepatic steatosis via hepatic PPARα activation. PHARMACEUTICAL BIOLOGY 2012; 50:1261-1268. [PMID: 22870903 DOI: 10.3109/13880209.2012.666982] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
CONTEXT The activation of peroxisome proliferator-activated receptor α (PPARα) target genes promotes hepatic oxidation of fatty acids. We hypothesized that Gyeongshingangjeehwan 18 (GGEx18), a mixture of three herbs, Laminaria japonica Aresch (Laminariaceae), Rheum palmatum L. (Polygonaceae), and Ephedra sinica Stapf (Ephedraceae), can regulate high-fat diet-induced hepatic steatosis through PPARα activation in the liver. OBJECTIVE To investigate the effects of GGEx18 on obesity-related hepatic steatosis and the responsible mechanism. MATERIALS AND METHODS The effects of GGEx18 on hepatic lipid accumulation, serum lipid profiles, and the expression of PPARα target genes were studied in high-fat diet-induced obese mice. The effects of GGEx18 on the expression of the PPARα targets and PPARα reporter gene activation were measured in NMu2Li liver cells. RESULTS GGEx18 administration to obese mice for 9 weeks markedly (p<0.05) decreased hepatic lipid accumulation compared with that in obese control mice. Serum triglyceride and total cholesterol levels were significantly (p <0.05) decreased by GGEx18. GGEx18 treatment increased the messenger RNA levels of PPARα target genes, which are responsible for fatty acid oxidation, in liver tissues. Consistent with the in vivo data, similar activation of genes was observed in GGEx18-treated NMu2Li liver cells. GGEx18 also elevated PPARα reporter gene expression in NMu2Li cells. DISCUSSION AND CONCLUSION These results suggest that GGEx18 prevents hepatic steatosis and hyperlipidemia in high-fat diet-induced obese mice, and this process may be mediated through PPARα activation in the liver.
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Affiliation(s)
- Soon Shik Shin
- Department of Formula Sciences, College of Oriental Medicine, Dongeui University, Busan, Korea
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18
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Shin SS, Park D, Lee HY, Hong Y, Choi J, Oh J, Lee H, Lee HR, Kim MR, Shen ZB, Cui HH, Yoon M. The herbal composition GGEx18 from Laminaria japonica, Rheum palmatum, and Ephedra sinica reduces obesity via skeletal muscle AMPK and PPARα. PHARMACEUTICAL BIOLOGY 2012; 50:506-15. [PMID: 22129093 DOI: 10.3109/13880209.2011.618502] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
CONTEXT Since AMP-activated protein kinase (AMPK) activation in skeletal muscle of obese rodents stimulates fatty acid oxidation, it is reasonable to hypothesize that pharmacological activation of AMPK might be of therapeutic benefit in obesity. OBJECTIVE To investigate the effects of the traditional Korean anti-obesity drug GGEx18, a mixture of three herbs, Laminaria japonica Aresch (Laminariaceae), Rheum palmatum L. (Polygonaceae), and Ephedra sinica Stapf (Ephedraceae), on obesity and the involvement of AMPK in this process. MATERIALS AND METHODS After high fat diet-induced obese mice were treated with GGEx18, we studied the effects of GGEx18 on body weight, fat mass, skeletal muscle lipid accumulation, and the expressions of AMPK, peroxisome proliferator-activated receptor ά (PPARα), and PPARα target genes. The effects of GGEx18 and/or the AMPK inhibitor compound C on lipid accumulation and expression of the above genes were measured in C2C12 skeletal muscle cells. RESULTS Administration of GGEx18 to obese mice for 9 weeks significantly (p < 0.05) decreased body and adipose tissue weights compared with obese control mice (p < 0.05). Lipid accumulation in skeletal muscle was inhibited by GGEx18. GGEx18 significantly (p < 0.05) increased skeletal muscle mRNA levels of AMPKα1 and AMPKα2 as well as PPARα and its target genes. Consistent with the in vivo data, GGEx18 inhibited lipid accumulation, and similar activation of genes was observed in GGEx18-treated C2C12 cells. However, compound C inhibited these effects in C2C12 cells. DISCUSSION AND CONCLUSION These results suggest that GGEx18 improves obesity through skeletal muscle AMPK and AMPK-stimulated expression of PPARα and its target enzymes for fatty acid oxidation.
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Affiliation(s)
- Soon Shik Shin
- Department of Formula Sciences, College of Oriental Medicine, Dongeui University, Busan 614-052
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Park SS, Kim E. Nur77 inhibits TR4-induced PEPCK expression in 3T3-L1 adipocytes. Anim Cells Syst (Seoul) 2012. [DOI: 10.1080/19768354.2011.603748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Plantier L, Besnard V, Xu Y, Ikegami M, Wert SE, Hunt AN, Postle AD, Whitsett JA. Activation of sterol-response element-binding proteins (SREBP) in alveolar type II cells enhances lipogenesis causing pulmonary lipotoxicity. J Biol Chem 2012; 287:10099-10114. [PMID: 22267724 DOI: 10.1074/jbc.m111.303669] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Pulmonary inflammation is associated with altered lipid synthesis and clearance related to diabetes, obesity, and various inherited metabolic disorders. In many tissues, lipogenesis is regulated at the transcriptional level by the activity of sterol-response element-binding proteins (SREBP). The role of SREBP activation in the regulation of lipid metabolism in the lung was assessed in mice in which both Insig1 and Insig2 genes, encoding proteins that bind and inhibit SREBPs in the endoplasmic reticulum, were deleted in alveolar type 2 cells. Although deletion of either Insig1 or Insig2 did not alter SREBP activity or lipid homeostasis, deletion of both genes (Insig1/2(Δ/Δ) mice) activated SREBP1, causing marked accumulation of lipids that consisted primarily of cholesterol esters and triglycerides in type 2 epithelial cells and alveolar macrophages. Neutral lipids accumulated in type 2 cells in association with the increase in mRNAs regulating fatty acid, cholesterol synthesis, and inflammation. Although bronchoalveolar lavage fluid phosphatidylcholine was modestly decreased, lung phospholipid content and lung function were maintained. Insig1/2(Δ/Δ) mice developed lung inflammation and airspace abnormalities associated with the accumulation of lipids in alveolar type 2 cells, alveolar macrophages, and within alveolar spaces. Deletion of Insig1/2 activated SREBP-enhancing lipogenesis in respiratory epithelial cells resulting in lipotoxicity-related lung inflammation and tissue remodeling.
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Affiliation(s)
- Laurent Plantier
- Section of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229 and
| | - Valérie Besnard
- Section of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229 and
| | - Yan Xu
- Section of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229 and
| | - Machiko Ikegami
- Section of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229 and
| | - Susan E Wert
- Section of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229 and
| | - Alan N Hunt
- Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Anthony D Postle
- Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Jeffrey A Whitsett
- Section of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229 and.
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Schröder A, Wollnik J, Wrzodek C, Dräger A, Bonin M, Burk O, Thomas M, Thasler WE, Zanger UM, Zell A. Inferring statin-induced gene regulatory relationships in primary human hepatocytes. Bioinformatics 2011; 27:2473-7. [DOI: 10.1093/bioinformatics/btr416] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Stapleton CM, Mashek DG, Wang S, Nagle CA, Cline GW, Thuillier P, Leesnitzer LM, Li LO, Stimmel JB, Shulman GI, Coleman RA. Lysophosphatidic acid activates peroxisome proliferator activated receptor-γ in CHO cells that over-express glycerol 3-phosphate acyltransferase-1. PLoS One 2011; 6:e18932. [PMID: 21533082 PMCID: PMC3080373 DOI: 10.1371/journal.pone.0018932] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 03/11/2011] [Indexed: 11/25/2022] Open
Abstract
Lysophosphatidic acid (LPA) is an agonist for peroxisome proliferator activated receptor-γ (PPARγ). Although glycerol-3-phosphate acyltransferase-1 (GPAT1) esterifies glycerol-3-phosphate to form LPA, an intermediate in the de novo synthesis of glycerolipids, it has been assumed that LPA synthesized by this route does not have a signaling role. The availability of Chinese Hamster Ovary (CHO) cells that stably overexpress GPAT1, allowed us to analyze PPARγ activation in the presence of LPA produced as an intracellular intermediate. LPA levels in CHO-GPAT1 cells were 6-fold higher than in wild-type CHO cells, and the mRNA abundance of CD36, a PPARγ target, was 2-fold higher. Transactivation assays showed that PPARγ activity was higher in the cells that overexpressed GPAT1. PPARγ activity was enhanced further in CHO-GPAT1 cells treated with the PPARγ ligand troglitazone. Extracellular LPA, phosphatidic acid (PA) or a membrane-permeable diacylglycerol had no effect, showing that PPARγ had been activated by LPA generated intracellularly. Transient transfection of a vector expressing 1-acylglycerol-3-phosphate acyltransferase-2, which converts endogenous LPA to PA, markedly reduced PPARγ activity, as did over-expressing diacylglycerol kinase, which converts DAG to PA, indicating that PA could be a potent inhibitor of PPARγ. These data suggest that LPA synthesized via the glycerol-3-phosphate pathway can activate PPARγ and that intermediates of de novo glycerolipid synthesis regulate gene expression.
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Affiliation(s)
- Cliona M. Stapleton
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Douglas G. Mashek
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Shuli Wang
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Cynthia A. Nagle
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Gary W. Cline
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Philippe Thuillier
- Oregon Cancer Institute, Oregon Health Sciences University, Portland, Oregon, United States of America
| | - Lisa M. Leesnitzer
- Department of Screening and Compound Profiling, GlaxoSmithKline Inc., Research Triangle Park, North Carolina, United States of America
| | - Lei O. Li
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Julie B. Stimmel
- Department of Screening and Compound Profiling, GlaxoSmithKline Inc., Research Triangle Park, North Carolina, United States of America
| | - Gerald I. Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Rosalind A. Coleman
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Nonylphenol-mediated CYP induction is PXR-dependent: The use of humanized mice and human hepatocytes suggests that hPXR is less sensitive than mouse PXR to nonylphenol treatment. Toxicol Appl Pharmacol 2011; 252:259-67. [PMID: 21376070 DOI: 10.1016/j.taap.2011.02.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/22/2011] [Accepted: 02/23/2011] [Indexed: 12/22/2022]
Abstract
Nonylphenol (NP), a by-product of alkylphenol ethoxylates, is a pervasive surfactant that activates the xenosensing nuclear receptor, the pregnane X-receptor (PXR) in transactivation assays in vitro. We are interested in determining if NP activates PXR in vivo, determining if hPXR and mPXR act similarly, and investigating the role of PXR in protecting individuals from NP. Wild-type (WT), PXR-null, and humanized PXR (hPXR) mice were treated with NP at 0, 50 or 75mg/kg/day for one week, and cytochrome P450 (CYP) induction, liver histopathology, and serum NP concentrations were examined. WT mice treated with NP showed induction of Cyp2b, and male-specific induction of Cyp2c and Cyp3a. CYPs were not induced in PXR-null mice, demonstrating that PXR is necessary for NP-mediated CYP induction. CAR-mediated CYP induction was not observed in the PXR-null mice despite previous data demonstrating that NP is also a CAR activator. hPXR mice only showed moderate Cyp induction, suggesting that hPXR is not as sensitive to NP as mPXR in vivo. NP-mediated Cyp3a induction from three human hepatocyte donors was not significant, confirming that hPXR is not very sensitive to NP-mediated CYP induction. Lastly, mice with PXR (mPXR and hPXR) showed lower NP serum concentrations than PXR-null mice treated with NP suggesting that PXR plays a role in decreasing liver toxicity by basally regulating phase I-III detoxification enzymes that promote the metabolism and elimination of NP. In summary, PXR is required for NP-mediated CYP-induction, mPXR mediates greater CYP induction than hPXR in vivo, and the presence of PXR, especially mPXR, is associated with altered histopathology and increased clearance of NP.
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Altered cerebellar development in nuclear receptor TAK1/ TR4 null mice is associated with deficits in GLAST(+) glia, alterations in social behavior, motor learning, startle reactivity, and microglia. THE CEREBELLUM 2011; 9:310-23. [PMID: 20393820 DOI: 10.1007/s12311-010-0163-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Previously, deficiency in the expression of the nuclear orphan receptor TAK1 was found to be associated with delayed cerebellar granule cell migration and Purkinje cell maturation with a permanent deficit in foliation of lobules VI–VII, suggesting a role for TAK1 in cerebellum development. In this study, we confirm that TAK1-deficient (TAK1(−/−)) mice have a smaller cerebellum and exhibit a disruption of lobules VI–VII. We extended these studies and show that at postnatal day 7, TAK1(−/−) mice exhibit a delay in monolayer maturation of dysmorphic calbindin 28K-positive Purkinje cells. The astrocyte-specific glutamate transporter (GLAST) was expressed within Bergmann fibers and internal granule cell layer at significantly lower levels in the cerebellum of TAK1(−/−) mice. At PND21, Golgi-positive Purkinje cells in TAK1(−/−) mice displayed a smaller soma (18%) and shorter distance to first branch point (35%). Neuronal death was not observed in TAK1(−/−) mice at PND21; however, activated microglia were present in the cerebellum, suggestive of earlier cell death. These structural deficits in the cerebellum were not sufficient to alter motor strength, coordination, or activity levels; however, deficits in acoustic startle response, prepulse startle inhibition, and social interactions were observed. Reactions to a novel environment were inhibited in a light/dark chamber, open-field, and home-cage running wheel. TAK1(−/−) mice displayed a plateau in performance on the running wheel, suggesting a deficit in learning to coordinate performance on a motor task. These data indicate that TAK1 is an important transcriptional modulator of cerebellar development and neurodevelopmentally regulated behavior.
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PPARα in Obesity: Sex Difference and Estrogen Involvement. PPAR Res 2010; 2010. [PMID: 20871824 PMCID: PMC2943125 DOI: 10.1155/2010/584296] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 07/08/2010] [Indexed: 12/13/2022] Open
Abstract
Peroxisome proliferator-activated receptor α (PPARα) is a member of the steroid hormone receptor superfamily and is well known to act as the molecular target for lipid-lowering drugs of the fibrate family. At the molecular level, PPARα regulates the transcription of a number of genes critical for lipid and lipoprotein metabolism. PPARα activators are further shown to reduce body weight gain and adiposity, at least in part, due to the increase of hepatic fatty acid oxidation and the decrease in levels of circulating triglycerides responsible for adipose cell hypertrophy and hyperplasia. However, these effects of the PPARα ligand fenofibrate on obesity are regulated with sexual dimorphism and seem to be influenced by the presence of functioning ovaries, suggesting the involvement of ovarian steroids in the control of obesity by PPARα. In female ovariectomized mice, 17β-estradiol inhibits the actions of fenofibrate on obesity through its suppressive effects on the expression of PPARα target genes, and these processes may be mediated by inhibiting the coactivator recruitment of PPARα. Thus, it is likely that PPARα functions on obesity may be enhanced in estrogen-deficient states.
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Shin SS, Jung YS, Yoon KH, Choi S, Hong Y, Park D, Lee H, Seo BI, Lee HY, Yoon M. The Korean traditional medicine gyeongshingangjeehwan inhibits adipocyte hypertrophy and visceral adipose tissue accumulation by activating PPARalpha actions in rat white adipose tissues. JOURNAL OF ETHNOPHARMACOLOGY 2010; 127:47-54. [PMID: 19799979 DOI: 10.1016/j.jep.2009.09.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 09/16/2009] [Accepted: 09/22/2009] [Indexed: 05/28/2023]
Abstract
AIM OF THE STUDY Gyeongshingangjeehwan (GGEx), which is a polyherbal drug composed of four medicinal plants, has traditionally been used as anti-obesity drug in Korean local clinics. Thus, we investigated the effects of GGEx on visceral adiposity and examined whether adipose peroxisome proliferator-activated receptor alpha (PPARalpha) activation is involved in this process. MATERIALS AND METHODS After Obese Otsuka Long-Evans Tokushima Fatty (OLETF) rats and differentiated 3T3-L1 adipocytes were treated with GGEx, we studied the effects of GGEx on not only visceral white adipose tissue (WAT) mass and adipocyte size, but also the expression of adipocyte marker and PPARalpha target genes. RESULTS Administration of GGEx to obese rats for 8 weeks decreased visceral WAT weight by 30% and the size of adipocytes in mesenteric WAT by 31% without weight changes of other organs. Concomitantly, GGEx increased mRNA levels of PPARalpha target genes responsible for fatty acid beta-oxidation in mesenteric WAT whereas decreased mRNA expression of adipocyte markers, such as PPARgamma, aP2 and leptin. Serological studies demonstrated that plasma levels of free fatty acids and triglycerides as well as insulin and glucose were decreased following GGEx treatment. Consistent with the in vivo data, GGEx increased PPARalpha reporter gene activity and induced the mRNA expression of PPARalpha target genes involved in mitochondrial fatty acid beta-oxidation in 3T3-L1 cells. GGEx also inhibited triglyceride accumulation in these cells. CONCLUSION These results suggest that GGEx promotes the reductions in visceral fat mass and adipocyte size in obese animals, and that this event may be mediated by adipose PPARalpha activation.
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Affiliation(s)
- Soon Shik Shin
- Department of Formula Sciences, College of Oriental Medicine, Dongeui University, Busan 614-052, Republic of Korea
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Huang YH, Liao CH, Chen RN, Liao CJ, Lin KH. Human testicular orphan receptor 4 enhances thyroid hormone receptor signaling. J Cell Physiol 2009; 222:347-56. [PMID: 19859911 DOI: 10.1002/jcp.21959] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The thyroid hormone receptor (TR) and human testicular orphan receptor 4 (TR4) belong to the nuclear hormone receptor superfamily. They are ligand-dependent transcription factors. TR and TR4 bind to a similar thyroid response element (TRE), known as a direct repeat with four nucleotide spacing (DR4). This study examined the possible interaction or cross-talking between those two receptors. We hypothesized that protein-protein interaction between TR4 and TR may promote TR-mediated transcriptional activity. Glutathione S-transferase pull-down and immunoprecipitation assays showed direct interaction between TR and TR4. Electrophoretic mobility-shift assay demonstrated that TR and TR4 could co-occupy the same TRE. The interaction between TR4 and TR may enhance regulation of genes targeted by TR, such as furin, fibrinogen, cdk2 and p21 expression. We found that TR4 function is similar with TR as TR4 alone could regulate expression of some TR target genes, and could increase cell migration or inhibit cell proliferation. Importantly, the TR-dependent inhibition of cell proliferation and stimulation of cell migration are more enhanced in the HepG2-TR cells stably over-expressing TR4. Overall, TR4 not only has modulation abilities similar to TR but also can cross-talk with TR and promote the TR signaling pathway.
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Affiliation(s)
- Ya-Hui Huang
- Department of Biochemistry, School of Medicine, Chang-Gung University, Taoyuan, Taiwan, Republic of China
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The roles of testicular orphan nuclear receptor 4 (TR4) in cerebellar development. THE CEREBELLUM 2009; 7:9-17. [PMID: 18418664 DOI: 10.1007/s12311-008-0006-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Since Testicular Receptor 4 (TR4) was cloned, efforts have been made to elucidate its physiological function. To examine the putative functions of TR4, the conventional TR4 knockout (TR4(-/-)) mouse model was generated. Throughout postnatal and adult stages, TR4(-/-) mice exhibited behavioral deficits in motor coordination, suggesting impaired cerebellar function. Histological examination of the postnatal and adult TR4(-/-) cerebellum revealed gross abnormalities in foliation. Further analyses demonstrated changes in the lamination of the TR4(-/-) cerebellar cortex, including reduction in the thickness of both the molecular layer (ML) and the internal granule layer (IGL). Analyses of the developing TR4(-/-) cerebellum indicate that the lamination irregularities observed may result from disrupted granule cell proliferation within the external granule cell layer (EGL), delayed inward migration of post-mitotic granule cells, and increased apoptosis during cerebellar development. In addition, abnormal development of Purkinje cells was observed in the postnatal TR4(-/-) cerebellum, as indicated by aberrant dendritic arborization. In postnatal, neuronal-specific TR4 knockout mice, architectural changes in the cerebellum were similar to those seen in TR4(-/-) animals, suggesting that TR4 function in neuronal lineages might be important for cerebellar morphogenesis, and that the effect on Purkinje cell development is likely mediated by changes elsewhere, such as in granule cells, or is highly dependent on developmental stage. Together, our findings from various TR4 knockout mouse models suggest that TR4 is required for normal cerebellar development and that failure to establish proper cytoarchitecture results in dysfunction of the cerebellum and leads to abnormal behavior.
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Klaunig JE, Babich MA, Baetcke KP, Cook JC, Corton JC, David RM, DeLuca JG, Lai DY, McKee RH, Peters JM, Roberts RA, Fenner-Crisp PA. PPARα Agonist-Induced Rodent Tumors: Modes of Action and Human Relevance. Crit Rev Toxicol 2008; 33:655-780. [PMID: 14727734 DOI: 10.1080/713608372] [Citation(s) in RCA: 433] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Widely varied chemicals--including certain herbicides, plasticizers, drugs, and natural products--induce peroxisome proliferation in rodent liver and other tissues. This phenomenon is characterized by increases in the volume density and fatty acid oxidation of these organelles, which contain hydrogen peroxide and fatty acid oxidation systems important in lipid metabolism. Research showing that some peroxisome proliferating chemicals are nongenotoxic animal carcinogens stimulated interest in developing mode of action (MOA) information to understand and explain the human relevance of animal tumors associated with these chemicals. Studies have demonstrated that a nuclear hormone receptor implicated in energy homeostasis, designated peroxisome proliferator-activated receptor alpha (PPARalpha), is an obligatory factor in peroxisome proliferation in rodent hepatocytes. This report provides an in-depth analysis of the state of the science on several topics critical to evaluating the relationship between the MOA for PPARalpha agonists and the human relevance of related animal tumors. Topics include a review of existing tumor bioassay data, data from animal and human sources relating to the MOA for PPARalpha agonists in several different tissues, and case studies on the potential human relevance of the animal MOA data. The summary of existing bioassay data discloses substantial species differences in response to peroxisome proliferators in vivo, with rodents more responsive than primates. Among the rat and mouse strains tested, both males and females develop tumors in response to exposure to a wide range of chemicals including DEHP and other phthalates, chlorinated paraffins, chlorinated solvents such as trichloroethylene and perchloroethylene, and certain pesticides and hypolipidemic pharmaceuticals. MOA data from three different rodent tissues--rat and mouse liver, rat pancreas, and rat testis--lead to several different postulated MOAs, some beginning with PPARalpha activation as a causal first step. For example, studies in rodent liver identified seven "key events," including three "causal events"--activation of PPARalpha, perturbation of cell proliferation and apoptosis, and selective clonal expansion--and a series of associative events involving peroxisome proliferation, hepatocyte oxidative stress, and Kupffer-cell-mediated events. Similar in-depth analysis for rat Leydig-cell tumors (LCTs) posits one MOA that begins with PPARalpha activation in the liver, but two possible pathways, one secondary to liver induction and the other direct inhibition of testicular testosterone biosynthesis. For this tumor, both proposed pathways involve changes in the metabolism and quantity of related hormones and hormone precursors. Key events in the postulated MOA for the third tumor type, pancreatic acinar-cell tumors (PACTs) in rats, also begin with PPARalpha activation in the liver, followed by changes in bile synthesis and composition. Using the new human relevance framework (HRF) (see companion article), case studies involving PPARalpha-related tumors in each of these three tissues produced a range of outcomes, depending partly on the quality and quantity of MOA data available from laboratory animals and related information from human data sources.
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Affiliation(s)
- James E Klaunig
- Indiana University School of Medicine, Indianapolis, IN, USA
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30
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Lee J, Chae K, Ha J, Park BY, Lee HS, Jeong S, Kim MY, Yoon M. Regulation of obesity and lipid disorders by herbal extracts from Morus alba, Melissa officinalis, and Artemisia capillaris in high-fat diet-induced obese mice. JOURNAL OF ETHNOPHARMACOLOGY 2008; 115:263-270. [PMID: 18023310 DOI: 10.1016/j.jep.2007.09.029] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Revised: 09/19/2007] [Accepted: 09/26/2007] [Indexed: 05/25/2023]
Abstract
Melissa officinalis L. (Labiatae), Morus alba L. (Moraceae), and Artemisia capillaris Thunb. (Compositae) are suggested to be involved in the regulation of hyperlipidemia. We hypothesized that Ob-X, a mixture of three herbs, Morus alba, Melissa officinalis and Artemisia capillaris [corrected] improves lipid metabolism, body weight gain and adiposity and that peroxisome proliferator-activated receptor alpha (PPARalpha) is associated with these events. Mice fed a high-fat diet for 12 weeks exhibited increases in body weight gain and adipose tissue mass compared with mice fed a low fat diet. However, feeding a high-fat diet supplemented with Ob-X significantly reduced these effects. Ob-X treatment also decreased the circulating levels of triglycerides and total cholesterol, and inhibited hepatic lipid accumulation. Ob-X supplementation was found to increase the hepatic mRNA levels of PPARalpha target enzymes responsible for fatty acid beta-oxidation. Moreover, Ob-X elevated the endogenous expression of a luciferase reporter gene containing three copies of a PPAR response element (PPRE) in NMu2Li liver cells. These data demonstrate that Ob-X regulates body weight gain, adipose tissue mass, and lipid metabolism in part through changes in the expression of hepatic PPARalpha target genes.
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Affiliation(s)
- Jinmi Lee
- Department of Life Sciences, Mokwon University, Daejon 302-729, Republic of Korea
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31
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Liu NC, Lin WJ, Kim E, Collins LL, Lin HY, Yu IC, Sparks JD, Chen LM, Lee YF, Chang C. Loss of TR4 orphan nuclear receptor reduces phosphoenolpyruvate carboxykinase-mediated gluconeogenesis. Diabetes 2007; 56:2901-9. [PMID: 17827404 DOI: 10.2337/db07-0359] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Regulation of phosphoenolpyruvate carboxykinase (PEPCK), the key gene in gluconeogenesis, is critical for glucose homeostasis in response to quick nutritional depletion and/or hormonal alteration. RESEARCH DESIGN/METHODS AND RESULTS Here, we identified the testicular orphan nuclear receptor 4 (TR4) as a key PEPCK regulator modulating PEPCK gene via a transcriptional mechanism. TR4 transactivates the 490-bp PEPCK promoter-containing luciferase reporter gene activity by direct binding to the TR4 responsive element (TR4RE) located at -451 to -439 in the promoter region. Binding to TR4RE was confirmed by electrophoretic mobility shift and chromatin immunoprecipitation assays. Eliminating TR4 via knockout and RNA interference (RNAi) in hepatocytes significantly reduced the PEPCK gene expression and glucose production in response to glucose depletion. In contrast, ectopic expression of TR4 increased PEPCK gene expression and hepatic glucose production in human and mouse hepatoma cells. Mice lacking TR4 also display reduction of PEPCK expression with impaired gluconeogenesis. CONCLUSIONS Together, both in vitro and in vivo data demonstrate the identification of a new pathway, TR4 --> PEPCK --> gluconeogenesis --> blood glucose, which may allow us to modulate metabolic programs via the control of a new key player, TR4, a member of the nuclear receptor superfamily.
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Affiliation(s)
- Ning-Chun Liu
- Department of Pathology, Cancer Center, University of Rochester, Rochester, NY 14642, USA
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Zhang Y, Chen YT, Xie S, Wang L, Lee YF, Chang SS, Chang C. Loss of Testicular Orphan Receptor 4 Impairs Normal Myelination in Mouse Forebrain. Mol Endocrinol 2007; 21:908-20. [PMID: 17227886 DOI: 10.1210/me.2006-0219] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Testicular orphan nuclear receptor 4 (TR4) has been suggested to play important roles in the development and functioning of the central nervous system (CNS). We find reduced myelination in TR4 knockout (TR4(-/-)) mice, which is particularly obvious in forebrains and in early developmental stages. Further analysis reveals that CC-1-positive (CC-1+) oligodendrocytes are decreased in TR4(-/-) forebrains. The O4+ signals are also reduced in TR4(-/-) forebrains when examined at postnatal d 7. However, the number and proliferation rate of platelet-derived growth factor receptor alpha-positive (PDGFalphaR+) oligodendrocyte precursor cells (OPCs) remain unaffected in these regions, suggesting that loss of TR4 interrupts oligodendrocyte differentiation. This is further supported by the observation that CC-1+ oligodendrocytes derived from 5-bromo-2'-deoxyuridine incorporating OPCs are significantly reduced in TR4(-/-) forebrains. We also find higher Jagged1 expression levels in axon fiber-enriched regions in TR4(-/-) forebrains, suggesting a more activated Notch signaling in these regions that correlates with previous reports showing that Notch activation inhibits oligodendrocyte differentiation. Together, our results suggest that TR4 is required for proper myelination in the CNS and is particularly important for oligodendrocyte differentiation and maturation in the forebrain regions. The altered Jagged1-Notch signaling in TR4(-/-) forebrain underlies a potential mechanism that contributes to the reduced myelination in the forebrain.
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Affiliation(s)
- Yanqing Zhang
- George Whipple Laboratory for Cancer Research, University of Rochester Medical Center, Rochester, New York 14642, USA
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33
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Michalik L, Auwerx J, Berger JP, Chatterjee VK, Glass CK, Gonzalez FJ, Grimaldi PA, Kadowaki T, Lazar MA, O'Rahilly S, Palmer CNA, Plutzky J, Reddy JK, Spiegelman BM, Staels B, Wahli W. International Union of Pharmacology. LXI. Peroxisome proliferator-activated receptors. Pharmacol Rev 2007; 58:726-41. [PMID: 17132851 DOI: 10.1124/pr.58.4.5] [Citation(s) in RCA: 705] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The three peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors of the nuclear hormone receptor superfamily. They share a high degree of structural homology with all members of the superfamily, particularly in the DNA-binding domain and ligand- and cofactor-binding domain. Many cellular and systemic roles have been attributed to these receptors, reaching far beyond the stimulation of peroxisome proliferation in rodents after which they were initially named. PPARs exhibit broad, isotype-specific tissue expression patterns. PPARalpha is expressed at high levels in organs with significant catabolism of fatty acids. PPARbeta/delta has the broadest expression pattern, and the levels of expression in certain tissues depend on the extent of cell proliferation and differentiation. PPARgamma is expressed as two isoforms, of which PPARgamma2 is found at high levels in the adipose tissues, whereas PPARgamma1 has a broader expression pattern. Transcriptional regulation by PPARs requires heterodimerization with the retinoid X receptor (RXR). When activated by a ligand, the dimer modulates transcription via binding to a specific DNA sequence element called a peroxisome proliferator response element (PPRE) in the promoter region of target genes. A wide variety of natural or synthetic compounds was identified as PPAR ligands. Among the synthetic ligands, the lipid-lowering drugs, fibrates, and the insulin sensitizers, thiazolidinediones, are PPARalpha and PPARgamma agonists, respectively, which underscores the important role of PPARs as therapeutic targets. Transcriptional control by PPAR/RXR heterodimers also requires interaction with coregulator complexes. Thus, selective action of PPARs in vivo results from the interplay at a given time point between expression levels of each of the three PPAR and RXR isotypes, affinity for a specific promoter PPRE, and ligand and cofactor availabilities.
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Affiliation(s)
- Liliane Michalik
- Center for Integrative Genomics, National Research Centre "Frontiers in Genetics," University of Lausanne, Lausanne, Switzerland
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Augereau P, Badia E, Carascossa S, Castet A, Fritsch S, Harmand PO, Jalaguier S, Cavaillès V. The nuclear receptor transcriptional coregulator RIP140. NUCLEAR RECEPTOR SIGNALING 2006; 4:e024. [PMID: 17088940 PMCID: PMC1630689 DOI: 10.1621/nrs.04024] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 10/17/2006] [Indexed: 12/21/2022]
Abstract
The nuclear receptor superfamily comprises ligand-regulated transcription factors that control various developmental and physiological pathways. These receptors share a common modular structure and regulate gene expression through the recruitment of a large set of coregulatory proteins. These transcription cofactors regulate, either positively or negatively, chromatin structure and transcription initiation. One of the first proteins to be identified as a hormone-recruited cofactor was RIP140. Despite its recruitment by agonist-liganded receptors, RIP140 exhibits a strong transcriptional repressive activity which involves several inhibitory domains and different effectors. Interestingly, the RIP140 gene, located on chromosome 21 in humans, is finely regulated at the transcriptional level by various nuclear receptors. In addition, the protein undergoes several post-translational modifications which control its repressive activity. Finally, experiments performed in mice devoid of the RIP140 gene indicate that this transcriptional cofactor is essential for female fertility and energy homeostasis. RIP140 therefore appears to be an important modulator of nuclear receptor activity which could play major roles in physiological processes and hormone-dependent diseases.
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Christian M, White R, Parker MG. Metabolic regulation by the nuclear receptor corepressor RIP140. Trends Endocrinol Metab 2006; 17:243-50. [PMID: 16815031 DOI: 10.1016/j.tem.2006.06.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 05/25/2006] [Accepted: 06/20/2006] [Indexed: 01/07/2023]
Abstract
Whereas the importance of activating gene expression in metabolic pathways to control energy homeostasis is well established, the contribution of transcriptional inhibition is less well defined. In this review we highlight a crucial role of RIP140, a transcriptional corepressor for nuclear receptors, in the regulation of energy expenditure. Mice devoid of the RIP140 gene are lean, exhibit resistance to high-fat-diet-induced obesity, and have increased glucose tolerance and insulin sensitivity. Consistent with these observations, RIP140 suppresses the expression of gene clusters that are involved in lipid and carbohydrate metabolism, including fatty acid oxidation, oxidative phosphorylation and mitochondrial uncoupling. Therefore, the functional interplay between transcriptional activators and the corepressor RIP140 is an essential process in metabolic regulation.
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Affiliation(s)
- Mark Christian
- Institute of Reproductive and Developmental Biology, Imperial College London, Faculty of Medicine, Du Cane Road, London W12 0NN, UK
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Nakajima T, Fujino S, Nakanishi G, Kim YS, Jetten AM. TIP27: a novel repressor of the nuclear orphan receptor TAK1/TR4. Nucleic Acids Res 2004; 32:4194-204. [PMID: 15302918 PMCID: PMC514368 DOI: 10.1093/nar/gkh741] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The nuclear orphan receptor TAK1/TR4 functions as a positive as well as a negative regulator of transcription; however, little is known about the factors regulating or mediating its activity. Yeast two-hybrid analysis using the ligand-binding domain (LBD) of TAK1 as bait identified a novel TAK1-interacting protein, referred to as TIP27, which functions as a repressor of TAK1-mediated transactivation. TIP27 is a 27 kDa protein containing two zinc finger motifs. Mammalian two-hybrid analysis showed that TIP27 interacts specifically with TAK1 and not with several other nuclear receptors tested. The region between Asp39 and Lys79 of TIP27, referred to as TAK1-interaction domain (TID), is critical for its interaction with TAK1 while the TAK1-LBD from helix 3 until the C-terminus is required for the optimal interaction with TIP27. Pull-down assays demonstrated that the TIP27 physically interacts with TAK1 and supported the critical importance of the TID. Confocal microscopy showed that in the nucleus, TIP27 and TAK1 co-localize. TIP27 acts as a strong repressor of DR1-dependent transcriptional activation by TAK1. This repression does not involve the inhibition of TAK1 homodimerization or DR1 binding but may be due to an effect on co-activator recruitment by TAK1. Our results indicate that TIP27 functions as a TAK1-selective repressor.
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Affiliation(s)
- Takeshi Nakajima
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
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Khan SA, Vanden Heuvel JP. Role of nuclear receptors in the regulation of gene expression by dietary fatty acids (review). J Nutr Biochem 2004; 14:554-67. [PMID: 14559106 DOI: 10.1016/s0955-2863(03)00098-6] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Long chain fatty acids, derived either from endogenous metabolism or by nutritional sources play significant roles in important biological processes of membrane structure, production of biologically active compounds, and participation in cellular signaling processes. Recently, the structure of dietary fatty acids has become an important issue in human health because ingestion of saturated fats (containing triglycerides composed of saturated fatty acids) is considered harmful, while unsaturated fats are viewed as beneficial. It is important to note that the molecular reason for this dichotomy still remains elusive. Since fatty acids are important players in development of pathology of cardiovascular and endocrine system, understanding the key molecular targets of fatty acids, in particular those that discriminate between saturated and unsaturated fats, is much needed. Recently, insights have been gained on several fatty acid-activated nuclear receptors involved in gene expression. In other words, we can now envision long chain fatty acids as regulators of signal transduction processes and gene regulation, which in turn will dictate their roles in health and disease. In this review, we will discuss fatty acid-mediated regulation of nuclear receptors. We will focus on peroxisome proliferators-activated receptors (PPARs), liver X receptors (LXR), retinoid X receptors (RXRs), and Hepatocyte Nuclear Factor alpha (HNF-4alpha), all of which play pivotal roles in dietary fatty acid-mediated effects. Also, the regulation of gene expression by Conjugated Linoleic Acids (CLA), a family of dienoic fatty acids with a variety of beneficial effects, will be discussed.
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Affiliation(s)
- Seher A Khan
- Department of Veterinary Science and Center for Molecular Toxicology and Carcinogenesis, Penn State University, University Park, PA 16802, USA
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Abstract
Nuclear orphan receptors represent a large and diverse subgroup in the nuclear receptor superfamily. Although putative ligands for these orphan members remain to be identified, some of these receptors possess intrinsic activating, inhibitory, or dual regulatory functions in development, differentiation, homeostasis, and reproduction. In particular, gene-silencing events elicited by chicken ovalbumin upstream promoter-transcription factors (COUP-TFs); dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1 (DAX-1); germ cell nuclear factor (GCNF); short heterodimer partner (SHP); and testicular receptors 2 and 4 (TR2 and TR4) are among the best characterized. These orphan receptors are critical in controlling basal activities or hormonal responsiveness of numerous target genes. They employ multiple and distinct mechanisms to mediate target gene repression. Complex cross-talk exists between these orphan receptors at their cognate DNA binding elements and an array of steroid?nonsteroid hormone receptors, other transcriptional activators, coactivators and corepressors, histone modification enzyme complexes, and components of basal transcriptional components. Therefore, perturbation induced by these orphan receptors at multiple levels, including DNA binding activities, receptor homo- or heterodimerization, recruitment of cofactor proteins, communication with general transcriptional machinery, and changes at histone acetylation status and chromatin structures, may contribute to silencing of target gene expression in a specific promoter or cell-type context. Moreover, the findings derived from gene-targeting studies have demonstrated the significance of these orphan receptors' function in physiologic settings. Thus, COUP-TFs, DAX-1, GCNF, SHP, and TR2 and 4 are known to be required for multiple physiologic and biologic functions, including neurogenesis and development of the heart and vascular system steroidogenesis and sex determination, gametogenesis and embryonic development, and cholesterol?lipid homeostasis.
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MESH Headings
- Animals
- COUP Transcription Factor I
- COUP Transcription Factors
- DAX-1 Orphan Nuclear Receptor
- DNA-Binding Proteins/metabolism
- Gametogenesis/physiology
- Gene Expression/physiology
- Gene Silencing/physiology
- Humans
- Models, Molecular
- Nuclear Receptor Subfamily 2, Group C, Member 1
- Nuclear Receptor Subfamily 6, Group A, Member 1
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Retinoic Acid/metabolism
- Receptors, Steroid/metabolism
- Receptors, Thyroid Hormone/metabolism
- Repressor Proteins/metabolism
- Transcription Factors/metabolism
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Affiliation(s)
- Ying Zhang
- Section on Molecular Endocrinology, Endocrinology, and Reproduction Research Branch, National Institutes of Health, Bethesda, Maryland 20892, USA
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Kim E, Xie S, Yeh SD, Lee YF, Collins LL, Hu YC, Shyr CR, Mu XM, Liu NC, Chen YT, Wang PH, Chang C. Disruption of TR4 orphan nuclear receptor reduces the expression of liver apolipoprotein E/C-I/C-II gene cluster. J Biol Chem 2003; 278:46919-26. [PMID: 12954636 DOI: 10.1074/jbc.m304088200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein E (apoE) is synthesized in many tissues, and the liver is the primary site from which apoE redistributes cholesterol and other lipids to peripheral tissues. Here we demonstrate that the TR4 orphan nuclear receptor (TR4) can induce apoE expression in HepG2 cells. This TR4-mediated regulation of apoE gene expression was further confirmed in vivo using TR4 knockout mice. Both serum apoE protein and liver apoE mRNA levels were significantly reduced in TR4 knockout mice. Gel shift and luciferase reporter gene assays further demonstrated that TR4 can induce apoE gene expression via a TR4 response element located in the hepatic control region that is 15 kb downstream of the apoE gene. Furthermore our in vivo data from TR4 knockout mice prove that TR4 can also regulate apolipoprotein C-I and C-II gene expression via the TR4 response element within the hepatic control region. Together our data show that loss of TR4 down-regulates expression of the apoE/C-I/C-II gene cluster in liver cells, demonstrating important roles of TR4 in the modulation of lipoprotein metabolism.
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Affiliation(s)
- Eungseok Kim
- George Whipple Laboratory for Cancer Research, University of Rochester Medical Center, Rochester, NY 14642, USA
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Yoon M, Lee H, Jeong S, Kim JJ, Nicol CJ, Nam KW, Kim M, Cho BG, Oh GT. Peroxisome proliferator-activated receptor alpha is involved in the regulation of lipid metabolism by ginseng. Br J Pharmacol 2003; 138:1295-302. [PMID: 12711630 PMCID: PMC1573779 DOI: 10.1038/sj.bjp.0705169] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Peroxisome proliferator-activated receptor alpha (PPARalpha) regulates the expression of the key genes involved in lipid metabolism following activation of this receptor by various ligands. Ginseng, a highly valuable medicine in oriental societies, is also reported to modulate lipid metabolism, although the mechanism of its action remains unknown. In order to test our hypothesis that ginseng exerts its effects by altering PPARalpha-mediated pathways, the effects of Korean red ginseng on PPARalpha function and serum lipid profiles were investigated using in vivo and in vitro approaches. 2. In vivo administration of ginseng extract (GE) and ginsenosides (GS) not only inhibited mRNA levels of acyl-CoA oxidase, a rate-limiting enzyme for PPARalpha-mediated peroxisomal fatty acid beta-oxidation, induced by the potent PPARalpha ligand Wy14,643 in a dose- and time-dependent manner, but also inhibited the induction of PPARalpha target genes expected following treatment with Wy14,643. 3. Consistent with the in vivo data, both GE and GS caused dose-dependent decreases in the endogenous expression of a luciferase reporter gene containing the PPAR responsive element (PPRE), while GS significantly decreased the magnitude of reporter gene activation in the presence of Wy14,643. 4. Serological studies demonstrated that, compared with vehicle-treated mice, treatment with GS significantly increased serum concentrations of total cholesterol, triglycerides, and high-density lipoprotein (HDL) cholesterol. Compared to groups treated with Wy14,643 alone, which significantly decreased serum triglyceride and HDL cholesterol levels versus controls, coadministration of either GE or GS with Wy14,643 modestly increased serum triglycerides and HDL cholesterol. 5. These results indicate that the effects of ginseng on serum lipid profiles may be mediated by changes in the expression of PPARalpha target genes, providing the first evidence that in vivo and in vitro treatments of ginseng modulate PPARalpha action. In addition, these data suggest that ginseng can act as an inhibitor of PPARalpha function, which may have therapeutic implications.
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Affiliation(s)
- Michung Yoon
- Department of Life Sciences, Mokwon University, Taejon 302-729, Republic of Korea.
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41
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Lin WJ, Li J, Lee YF, Yeh SD, Altuwaijri S, Ou JH, Chang C. Suppression of hepatitis B virus core promoter by the nuclear orphan receptor TR4. J Biol Chem 2003; 278:9353-60. [PMID: 12522137 DOI: 10.1074/jbc.m205944200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The TR4 orphan receptor is a member of the nuclear receptor superfamily that modulates gene expression via binding to the AGGTCA direct repeat hormone response element. Here we report a functional study of TR4 interaction with the core promoter of the hepatitis B virus (HBV). The electrophoretic mobility shift assay shows that TR4 can bind to the direct repeat 1 sequence element (AGGTTAAAGGTCT, nucleotide coordinates 1757-1769, TR4RE-HBV) on the HBV core promoter. TR4 also can enhance the activity of a synthetic luciferase reporter linked with four copies of TR4RE-HBV in either liver HepG2 or non-liver H1299 cells in a dose-dependent manner. Surprisingly, TR4 represses the activity of a luciferase reporter containing the entire HBV genome sequences. Moreover, mutation of this TR4RE-HBV site in the HBV core promoter diminishes the TR4 suppression effect. This TR4-induced suppression of HBV core promoter activity is further confirmed by primer extension analysis of the HBV core RNAs, showing that TR4 represses both pre-core and core mRNAs. Further dissection of this repressive mechanism indicates that TR4 may suppress the HBV core promoter activity via repressing HNF4alpha-mediated transactivation by protein-protein interactions without inhibition of HNF4alpha DNA binding. Furthermore, our results indicate that the N- and C-terminal regions of TR4 protein are required for TR4-HNF4alpha interaction. It is possible that TR4-HNF4alpha interaction may block the HNF4alpha function that results in the suppression of HBV gene expression. Together, these results demonstrate that TR4 can serve as a negative modulator in the transcriptional regulation of HBV core gene expression.
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Affiliation(s)
- Wen-Jye Lin
- George Whipple Lab for Cancer Research, Department of Pathology, University of Rochester Medical Center, Rochester, New York 14642, USA
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42
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Yan Z, Kim YS, Jetten AM. RAP80, a novel nuclear protein that interacts with the retinoid-related testis-associated receptor. J Biol Chem 2002; 277:32379-88. [PMID: 12080054 DOI: 10.1074/jbc.m203475200] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we describe the characterization of a novel nuclear protein, referred to as RAP80. The RAP80 cDNA was cloned from a human testis cDNA library and encodes a 719-amino acid protein containing two potential CX(2)CX(11)HX(3)C-type zinc finger motifs at its carboxyl-terminal region. Analysis of its genomic structure revealed that the RAP80 gene covers more than 90 kb and consists of 15 exons and 14 introns. Fluorescence in situ hybridization mapped the RAP80 gene to human chromosome 5q35. RAP80 mRNA is expressed in many human tissues, but its expression is particularly high in testis. In situ hybridization showed that RAP80 is highly expressed in germ cells of mouse testis but is not differentially regulated during spermatogenesis. Confocal microscopy showed that RAP80 is localized to the nucleus, where it is distributed in a speckled pattern. Deletion analysis showed that a bipartite nuclear localization signal at the amino terminus is important in mediating nuclear transport of RAP80. Monohybrid analysis showed that RAP80 might function as an active repressor of transcription. Mammalian two-hybrid analysis demonstrated that RAP80 was able to interact with the retinoid-related testis-associated receptor (RTR), an orphan receptor that has been implicated in the control of embryonic development and spermatogenesis. Pull-down analysis showed that RAP80 and RTR physically interact in vitro. Deletion and point mutation analyses revealed that part of the hinge domain of RTR is required for this interaction. RAP80 is able to inhibit the interaction of RTR with the co-repressor N-CoR likely by competing with N-CoR for RTR binding. Our results suggest that RAP80 may be functioning as a modulator of RTR signaling.
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Affiliation(s)
- Zhijiang Yan
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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43
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Lee YF, Lee HJ, Chang C. Recent advances in the TR2 and TR4 orphan receptors of the nuclear receptor superfamily. J Steroid Biochem Mol Biol 2002; 81:291-308. [PMID: 12361719 DOI: 10.1016/s0960-0760(02)00118-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The human testicular receptor 2 (TR2) and TR4 orphan receptors are two evolutionarily related proteins belonging to the nuclear receptor superfamily. Numerous TR2 and TR4 variants and homologs have been identified from different species, including vertebrates (e.g. human, murine, rabbit, fish, and amphibian) and invertebrates (e.g. Drosophila, sea urchin, and nematode) since TR2 was initially isolated over a decade ago. Specific tissue distribution, genomic organization, and chromosomal assignment of both orphan receptors have been investigated. In order to reveal the physiological functions played by both TR2 and TR4, upstream modulators of TR2 and TR4 gene expression, their downstream target gene regulation, feedback mechanisms, and differential modulation mediated by the recruitment of other nuclear receptors and coregulators have been investigated. Studies summarized in the present report have provided unexpected insights into the TR2 and TR4 functions in a variety of biological processes. The essential and difficult tasks of identifying orphan receptor ligands, agonist/antagonist assignment, their physiological functions, and mechanisms of action will continue to challenge nuclear receptor researchers in the future.
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Affiliation(s)
- Yi-Fen Lee
- George Whipple Laboratory for Cancer Research, Department of Urology, University of Rochester, NY 14642, USA
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44
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Shyr CR, Hu YC, Kim E, Chang C. Modulation of estrogen receptor-mediated transactivation by orphan receptor TR4 in MCF-7 cells. J Biol Chem 2002; 277:14622-8. [PMID: 11844790 DOI: 10.1074/jbc.m110051200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The human testicular orphan receptor 4 (TR4) is a member of the nuclear receptor superfamily that shows a broad tissue distribution with higher expression in the nervous system and male reproductive tract. TR4 functions as a transcriptional modulator that controls various target genes via binding to the DNA hormone response elements. Here we report that instead of direct binding to hormone response elements for gene regulation, TR4 can also go through direct protein-protein interaction to repress estrogen receptor (ER)-mediated transactivation. Electrophoretic mobility shift and glutathione S-transferase pull-down assays clearly demonstrate that the direct interaction between TR4 and ER will inhibit the homodimerization of ER and interrupt/prevent ER binding to the estrogen response element. The consequence of these events may then result in the suppression of ER target genes, such as cyclin D1 and pS2 and inhibition of ER-mediated cell proliferation in the MCF-7 cells stably transfected with TR4. Together, our results showing that TR4 can suppress ER function via protein-protein interaction not only represent a unique cross-talk signaling pathway in the nuclear receptor superfamily, it may also provide us with a new strategy to modulate ER function in the breast cancer cells.
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Affiliation(s)
- Chih-Rong Shyr
- George Whipple Laboratory for Cancer Research, Department of Pathology, University of Rochester Medical Center, Rochester, New York 14642, USA
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45
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Akiyama TE, Baumann CT, Sakai S, Hager GL, Gonzalez FJ. Selective intranuclear redistribution of PPAR isoforms by RXR alpha. Mol Endocrinol 2002; 16:707-21. [PMID: 11923467 DOI: 10.1210/mend.16.4.0797] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The intracellular localization of transcriptionally active green fluorescent protein (GFP) chimeras linked to PPARs for human PPAR alpha (GFP-PPARh alpha) and mouse PPAR alpha, beta, and gamma 1 (GFP-PPARm alpha, GFP-PPARm beta, and GFP-PPARm gamma, respectively) was examined in the mouse hepatoma cell line, Hepa-1, using fluorescence microscopy. A predominantly nuclear and diffuse distribution of each isoform was found in both the presence and absence of specific ligands for each receptor. GFP-PPARm alpha-G (containing a Glu282Gly substitution of PPARm alpha) and a phosphorylation mutant, GFP-PPARm gamma-A (containing a Ser82Ala substitution of PPARm gamma), exhibited altered transcriptional activities, but displayed similar intracellular localization patterns compared with their respective wild-type receptors. Coexpression of nuclear receptor corepressor suppressed, whereas steroid receptor coactivator-1 enhanced the transcriptional activity of each of the GFP-PPAR isoforms, but did not discernibly alter their intracellular distributions, both in the presence and absence of PPAR ligands. Interestingly, coexpression of the obligate heterodimeric partner of PPARs, RXR alpha, resulted in an intranuclear redistribution of the GFP-PPARm gamma isoform characterized by a reticulated pattern of the green fluorescent label for PPAR gamma within the nucleus, but not in nucleoli, and a heightened concentration of the fluorescent label surrounding nucleolar structures and at the nuclear membrane. Conversely, coexpression of yellow fluorescent protein-RXR alpha and native PPARm gamma resulted in a similar distribution of the yellow fluorescent tag. This localization pattern was not discernibly altered by PPAR gamma or RXR alpha-specific ligands. These results implicate RXR alpha in the nuclear reorganization of PPAR gamma and suggest that PPAR gamma colocalizes with RXR alpha at specific locations within the nucleus independent of added ligand.
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Affiliation(s)
- Taro E Akiyama
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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46
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Lee HJ, Lee YF, Chang C. TR4 orphan receptor represses the human steroid 21-hydroxylase gene expression through the monomeric AGGTCA motif. Biochem Biophys Res Commun 2001; 285:1361-8. [PMID: 11478808 DOI: 10.1006/bbrc.2001.5342] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The human TR4 orphan receptor (TR4) is a member of the nuclear receptor superfamily. It functions as a transcriptional factor which regulates and controls many important physiological functions. It has been documented that TR4 may bind as a homodimer to a DNA response element containing two direct repeats of the AGGTCA consensus motif. Surprisingly, our data reveal that the expression of the human steroid 21-hydroxylase (21-OHase) gene could be repressed by TR4 via the monomeric AGGTCA motif (-228TR4RE) at its 5' flanking region (nucleotide numbers 1431-1444, 5'-GGAAAAAGGTCAGG-3'). Electrophoretic mobility shift assay showed specific binding with a dissociation constant of 0.4 nM between TR4 and the monomeric -288TR4RE motif. However, TR4 does not form heterodimers with either retinoid X receptor alpha or SHP (short heterodimer partner) orphan receptor. Additionally, both dual-luciferase and chloramphenicol acetyltransferase assays demonstrated that TR4 can function as a repressor via the -228TR4RE of the 21-OHase gene. In conclusion, our data suggest that TR4 may bind to a monomeric DNA response element and play an important role in the suppression of the 21-OHase gene expression.
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Affiliation(s)
- H J Lee
- Institute of Biotechnology, National Dong Hwa University, Hualien, Taiwan, 974, Republic of China.
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Abstract
Members of the nuclear-receptor superfamily mediate crucial physiological functions by regulating the synthesis of their target genes. Nuclear receptors are usually activated by ligand binding. Cytochrome P450 (CYP) isoforms often catalyse both formation and degradation of these ligands. CYPs also metabolize many exogenous compounds, some of which may act as activators of nuclear receptors and disruptors of endocrine and cellular homoeostasis. This review summarizes recent findings that indicate that major classes of CYP genes are selectively regulated by certain ligand-activated nuclear receptors, thus creating tightly controlled networks.
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Hansen JB, Zhang H, Rasmussen TH, Petersen RK, Flindt EN, Kristiansen K. Peroxisome proliferator-activated receptor delta (PPARdelta )-mediated regulation of preadipocyte proliferation and gene expression is dependent on cAMP signaling. J Biol Chem 2001; 276:3175-82. [PMID: 11069900 DOI: 10.1074/jbc.m005567200] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The peroxisome proliferator-activated receptor gamma (PPARgamma) is a key regulator of terminal adipocyte differentiation. PPARdelta is expressed in preadipocytes, but the importance of this PPAR subtype in adipogenesis has been a matter of debate. Here we present a critical evaluation of the role of PPARdelta in adipocyte differentiation. We demonstrate that treatment of NIH-3T3 fibroblasts overexpressing PPARdelta with standard adipogenic inducers led to induction of PPARgamma2 expression and terminal adipocyte differentiation in a manner that was strictly dependent on simultaneous administration of a PPARdelta ligand and methylisobutylxanthine (MIX) or other cAMP elevating agents. We further show that ligands and MIX synergistically stimulated PPARdelta-mediated transactivation. In 3T3-L1 preadipocytes, simultaneous administration of a PPARdelta-selective ligand and MIX significantly enhanced the early expression of PPARgamma and ALBP/aP2, but only modestly promoted terminal differentiation as determined by lipid accumulation. Finally, we provide evidence that synergistic activation of PPARdelta promotes mitotic clonal expansion in 3T3-L1 cells with or without forced expression of PPARdelta. In conclusion, our results suggest that PPARdelta may play a role in the proliferation of adipocyte precursor cells, whereas activation of endogenous PPARdelta in 3T3-L1 cells appears to have only minor impact on the processes leading to terminal adipocyte differentiation.
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Affiliation(s)
- J B Hansen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense University, DK-5230 Odense M, Denmark
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49
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Yan Z, Jetten AM. Characterization of the repressor function of the nuclear orphan receptor retinoid receptor-related testis-associated receptor/germ cell nuclear factor. J Biol Chem 2000; 275:35077-85. [PMID: 10940306 DOI: 10.1074/jbc.m005566200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retinoid receptor-related testis-associated receptor (RTR)/germ cell nuclear factor is a nuclear orphan receptor that plays an important role in the control of gene expression during early embryonic development and gametogenesis. It has been shown to repress transcriptional activation. In this study, we further characterize this repressor function. We demonstrate that RTR can suppress the transcriptional activation induced by the estrogen receptor related-receptor alpha1 through its response element. The latter is at least in part due to competition for binding to the same response element. In addition, RTR inhibits basal transcriptional activation, indicating that it functions as an active repressor. Mammalian two-hybrid analyses showed that RTR interacts with the co-repressor nuclear co-repressor (N-CoR) but is unable to interact with the co-repressor SMRT or RIP140. Pull-down analyses with glutathione S-transferase-RTR fusion protein demonstrated that RTR physically interacts with N-CoR in vitro, suggesting a potential role for N-CoR in the transcriptional repression by RTR. To identify the regions in RTR essential for the binding of RTR to N-CoR, the effect of various deletion and point mutations on this interaction was examined. This analysis revealed that this interaction requires the hinge domain, helix 3 as well as the helix 12 region of RTR. The residues Ser(246)-Tyr(247) in the hinge domain, Lys(318) in helix 3, and Lys(489)-Thr(490) in helix 12 are identified as being critical in this interaction. Our results demonstrate that RTR can function as an active transcriptional repressor and that this repression can be mediated through interactions with the co-repressor N-CoR. We show that this interaction exhibits several characteristics unique to RTR. Through its repressor function, RTR can suppress the induction of transcriptional activation by other nuclear receptors. These repressor activities may provide important mechanisms by which RTR regulates gene expression during development and gametogenesis.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Amino Acid Sequence
- Animals
- CHO Cells
- Cell Nucleus/metabolism
- Cricetinae
- DNA-Binding Proteins/chemistry
- DNA-Binding Proteins/metabolism
- Electrophoresis, Polyacrylamide Gel
- Gene Deletion
- Gene Expression Regulation, Developmental
- Glutathione Transferase/metabolism
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Nuclear Proteins/metabolism
- Nuclear Receptor Co-Repressor 1
- Nuclear Receptor Co-Repressor 2
- Nuclear Receptor Interacting Protein 1
- Nuclear Receptor Subfamily 6, Group A, Member 1
- Plasmids/metabolism
- Point Mutation
- Protein Binding
- Protein Structure, Tertiary
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Estrogen/metabolism
- Receptors, Retinoic Acid/chemistry
- Receptors, Retinoic Acid/metabolism
- Recombinant Fusion Proteins/metabolism
- Repressor Proteins/metabolism
- Response Elements
- Sequence Homology, Amino Acid
- Transcription, Genetic
- Transcriptional Activation
- Two-Hybrid System Techniques
- ERRalpha Estrogen-Related Receptor
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Affiliation(s)
- Z Yan
- Cell Biology Section, Laboratory of Pulmonary Pathobiology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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50
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Corton JC, Anderson SP, Stauber A. Central role of peroxisome proliferator-activated receptors in the actions of peroxisome proliferators. Annu Rev Pharmacol Toxicol 2000; 40:491-518. [PMID: 10836145 DOI: 10.1146/annurev.pharmtox.40.1.491] [Citation(s) in RCA: 260] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Peroxisome proliferators (PPs) are a large class of structurally dissimilar chemicals that have diverse effects in rodents and humans. Most, if not all, of the diverse effects of PPs are mediated by three members of the nuclear receptor superfamily called peroxisome proliferator-activated receptors (PPARs). In this review, we define the molecular mechanisms of PPs, including PPAR binding specificity, alteration of gene expression through binding to DNA response elements, and cross talk with other signaling pathways. We discuss the roles of PPARs in growth promotion in rodent hepatocarcinogenesis and potential therapeutic effects, including suppression of cancer growth and inflammation.
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Affiliation(s)
- J C Corton
- Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709-2137, USA.
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