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Mueller E. Browning and Graying: Novel Transcriptional Regulators of Brown and Beige Fat Tissues and Aging. Front Endocrinol (Lausanne) 2016; 7:19. [PMID: 26973598 PMCID: PMC4773441 DOI: 10.3389/fendo.2016.00019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/15/2016] [Indexed: 11/13/2022] Open
Abstract
Obesity represents a major risk factor for the development of a number of metabolic disorders, including cardiovascular disease and type 2 diabetes. Since the discovery that brown and beige fat cells exist in adult humans and contribute to energy expenditure, increasing interest has been devoted to the understanding of the molecular switches turning on calorie utilization. It has been reported that the ability of thermogenic tissues to burn energy declines during aging, possibly contributing to the development of metabolic dysfunction late in life. This review will focus on the recently identified transcriptional modulators of brown and beige cells and will discuss the potential impact of some of these thermogenic factors on age-associated metabolic disorders.
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Affiliation(s)
- Elisabetta Mueller
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
- *Correspondence: Elisabetta Mueller,
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Abstract
Since brown adipose tissue (BAT) dissipates energy through UCP1, BAT has garnered attention as a therapeutic intervention for obesity and metabolic diseases including type 2 diabetes. As we better understand the physiological roles of classical brown and beige adipocytes, it is becoming clear that BAT is not simply a heat-generating organ. Increased beige fat mass in response to a variety of external/internal cues is associated with significant improvements in glucose and lipid homeostasis that may not be entirely mediated by UCP1. We aim to discuss recent insights regarding the developmental lineages, molecular regulation, and new functions for brown and beige adipocytes.
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Affiliation(s)
- Shingo Kajimura
- UCSF Diabetes Center and Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143-0669, USA.
| | - Bruce M Spiegelman
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA.
| | - Patrick Seale
- Institute for Diabetes, Obesity, and Metabolism, Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Zhang H, Guan M, Townsend KL, Huang TL, An D, Yan X, Xue R, Schulz TJ, Winnay J, Mori M, Hirshman MF, Kristiansen K, Tsang JS, White AP, Cypess AM, Goodyear LJ, Tseng YH. MicroRNA-455 regulates brown adipogenesis via a novel HIF1an-AMPK-PGC1α signaling network. EMBO Rep 2015; 16:1378-93. [PMID: 26303948 DOI: 10.15252/embr.201540837] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 07/24/2015] [Indexed: 01/06/2023] Open
Abstract
Brown adipose tissue (BAT) dissipates chemical energy as heat and can counteract obesity. MicroRNAs are emerging as key regulators in development and disease. Combining microRNA and mRNA microarray profiling followed by bioinformatic analyses, we identified miR-455 as a new regulator of brown adipogenesis. miR-455 exhibits a BAT-specific expression pattern and is induced by cold and the browning inducer BMP7. In vitro gain- and loss-of-function studies show that miR-455 regulates brown adipocyte differentiation and thermogenesis. Adipose-specific miR-455 transgenic mice display marked browning of subcutaneous white fat upon cold exposure. miR-455 activates AMPKα1 by targeting HIF1an, and AMPK promotes the brown adipogenic program and mitochondrial biogenesis. Concomitantly, miR-455 also targets the adipogenic suppressors Runx1t1 and Necdin, initiating adipogenic differentiation. Taken together, the data reveal a novel microRNA-regulated signaling network that controls brown adipogenesis and may be a potential therapeutic target for human metabolic disorders.
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Affiliation(s)
- Hongbin Zhang
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Meiping Guan
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Department of Endocrinology and Metabolism, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Kristy L Townsend
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Tian Lian Huang
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Ding An
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Xu Yan
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Ruidan Xue
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Tim J Schulz
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Adipocyte Development Research Group, German Institute of Human Nutrition, Potsdam, Germany
| | - Jonathon Winnay
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Marcelo Mori
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Department of Biophysics, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Michael F Hirshman
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | | | - John S Tsang
- Systems Genomics and Bioinformatics Unit, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases (NIAID) and Trans-NIH Center for Human Immunology, National Institutes of Health, Bethesda, MD, USA
| | - Andrew P White
- Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Aaron M Cypess
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Laurie J Goodyear
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Yu-Hua Tseng
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
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Sand LGL, Szuhai K, Hogendoorn PCW. Sequencing Overview of Ewing Sarcoma: A Journey across Genomic, Epigenomic and Transcriptomic Landscapes. Int J Mol Sci 2015; 16:16176-215. [PMID: 26193259 PMCID: PMC4519945 DOI: 10.3390/ijms160716176] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 07/03/2015] [Accepted: 07/07/2015] [Indexed: 12/17/2022] Open
Abstract
Ewing sarcoma is an aggressive neoplasm occurring predominantly in adolescent Caucasians. At the genome level, a pathognomonic EWSR1-ETS translocation is present. The resulting fusion protein acts as a molecular driver in the tumor development and interferes, amongst others, with endogenous transcription and splicing. The Ewing sarcoma cell shows a poorly differentiated, stem-cell like phenotype. Consequently, the cellular origin of Ewing sarcoma is still a hot discussed topic. To further characterize Ewing sarcoma and to further elucidate the role of EWSR1-ETS fusion protein multiple genome, epigenome and transcriptome level studies were performed. In this review, the data from these studies were combined into a comprehensive overview. Presently, classical morphological predictive markers are used in the clinic and the therapy is dominantly based on systemic chemotherapy in combination with surgical interventions. Using sequencing, novel predictive markers and candidates for immuno- and targeted therapy were identified which were summarized in this review.
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Affiliation(s)
- Laurens G L Sand
- Department of Pathology, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands.
| | - Karoly Szuhai
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands.
| | - Pancras C W Hogendoorn
- Department of Pathology, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands.
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Seale P. Transcriptional Regulatory Circuits Controlling Brown Fat Development and Activation. Diabetes 2015; 64:2369-75. [PMID: 26050669 PMCID: PMC4477361 DOI: 10.2337/db15-0203] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/11/2015] [Indexed: 12/15/2022]
Abstract
Brown and beige adipose tissue is specialized for heat production and can be activated to reduce obesity and metabolic dysfunction in animals. Recent studies also have indicated that human brown fat activity levels correlate with leanness. This has revitalized interest in brown fat biology and has driven the discovery of many new regulators of brown fat development and function. This review summarizes recent advances in our understanding of the transcriptional mechanisms that control brown and beige fat cell development.
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Affiliation(s)
- Patrick Seale
- Institute for Diabetes, Obesity and Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
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Abstract
There are three different types of adipose tissue (AT)-brown, white, and beige-that differ with stage of development, species, and anatomical location. Of these, brown AT (BAT) is the least abundant but has the greatest potential impact on energy balance. BAT is capable of rapidly producing large amounts of heat through activation of the unique uncoupling protein 1 (UCP1) located within the inner mitochondrial membrane. White AT is an endocrine organ and site of lipid storage, whereas beige AT is primarily white but contains some cells that possess UCP1. BAT first appears in the fetus around mid-gestation and is then gradually lost through childhood, adolescence, and adulthood. We focus on the interrelationships between adipocyte classification, anatomical location, and impact of diet in early life together with the extent to which fat development differs between the major species examined. Ultimately, novel dietary interventions designed to reactivate BAT could be possible.
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Affiliation(s)
- Michael E Symonds
- Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham NG7 2UH, United Kingdom; , ,
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Inactivation of EWS reduces PGC-1α protein stability and mitochondrial homeostasis. Proc Natl Acad Sci U S A 2015; 112:6074-9. [PMID: 25918410 DOI: 10.1073/pnas.1504391112] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
EWS (Ewing sarcoma) encodes an RNA/ssDNA binding protein that is frequently rearranged in a number of different cancers by chromosomal translocations. Physiologically, EWS has diverse and essential roles in various organ development and cellular processes. In this study, we uncovered a new role of EWS in mitochondrial homeostasis and energy metabolism. Loss of EWS leads to a significant decrease in mitochondria abundance and activity, which is caused by a rapid degradation of Peroxisome proliferator-activated receptor γ Coactivator (PGC-1α), a central regulator of mitochondria biogenesis, function, and cellular energy metabolism. EWS inactivation leads to increased ubiquitination and proteolysis of PGC-1α via proteasome pathway. Complementation of EWS in Ews-deficient cells restores PGC-1α and mitochondrial abundance. We found that expression of E3 ubiquitin ligase, FBXW7 (F-box/WD40 domain protein 7), is increased in the absence of Ews and depletion of Fbxw7 in Ews-null cells restores PGC-1α expression and mitochondrial density. Consistent with these findings, mitochondrial abundance and activity are significantly reduced in brown fat and skeletal muscles of Ews-deficient mice. Furthermore, expression of mitochondrial biogenesis, respiration and fatty acid β-oxidation genes is significantly reduced in the liver of Ews-null mice. These results demonstrate a novel role of EWS in mitochondrial and cellular energy homeostasis by controlling PGC-1α protein stability, and further implicate altered mitochondrial and energy metabolism in cancers harboring the EWS translocation.
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58
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Basse AL, Dixen K, Yadav R, Tygesen MP, Qvortrup K, Kristiansen K, Quistorff B, Gupta R, Wang J, Hansen JB. Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling. BMC Genomics 2015; 16:215. [PMID: 25887780 PMCID: PMC4407871 DOI: 10.1186/s12864-015-1405-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/26/2015] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Large mammals are capable of thermoregulation shortly after birth due to the presence of brown adipose tissue (BAT). The majority of BAT disappears after birth and is replaced by white adipose tissue (WAT). RESULTS We analyzed the postnatal transformation of adipose in sheep with a time course study of the perirenal adipose depot. We observed changes in tissue morphology, gene expression and metabolism within the first two weeks of postnatal life consistent with the expected transition from BAT to WAT. The transformation was characterized by massively decreased mitochondrial abundance and down-regulation of gene expression related to mitochondrial function and oxidative phosphorylation. Global gene expression profiling demonstrated that the time points grouped into three phases: a brown adipose phase, a transition phase and a white adipose phase. Between the brown adipose and the transition phase 170 genes were differentially expressed, and 717 genes were differentially expressed between the transition and the white adipose phase. Thirty-eight genes were shared among the two sets of differentially expressed genes. We identified a number of regulated transcription factors, including NR1H3, MYC, KLF4, ESR1, RELA and BCL6, which were linked to the overall changes in gene expression during the adipose tissue remodeling. Finally, the perirenal adipose tissue expressed both brown and brite/beige adipocyte marker genes at birth, the expression of which changed substantially over time. CONCLUSIONS Using global gene expression profiling of the postnatal BAT to WAT transformation in sheep, we provide novel insight into adipose tissue plasticity in a large mammal, including identification of novel transcriptional components linked to adipose tissue remodeling. Moreover, our data set provides a useful resource for further studies in adipose tissue plasticity.
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Affiliation(s)
- Astrid L Basse
- Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark.
- Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
| | - Karen Dixen
- Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark.
- Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
| | - Rachita Yadav
- Department of Biology, University of Copenhagen, DK-2100, Copenhagen, Denmark.
- Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
| | - Malin P Tygesen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, DK-1870, Frederiksberg, Denmark.
| | - Klaus Qvortrup
- Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark.
| | - Karsten Kristiansen
- Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
| | - Bjørn Quistorff
- Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark.
| | - Ramneek Gupta
- Department of Biology, University of Copenhagen, DK-2100, Copenhagen, Denmark.
| | - Jun Wang
- Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
- BGI-Shenzhen, Shenzhen, 518083, China.
- Princess Al Jawhara Center of Excellence in the Research of Hereditary Disorders, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
- Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau, 999078, China.
| | - Jacob B Hansen
- Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
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Oncogenic fusion protein EWS-FLI1 is a network hub that regulates alternative splicing. Proc Natl Acad Sci U S A 2015; 112:E1307-16. [PMID: 25737553 DOI: 10.1073/pnas.1500536112] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The synthesis and processing of mRNA, from transcription to translation initiation, often requires splicing of intragenic material. The final mRNA composition varies based on proteins that modulate splice site selection. EWS-FLI1 is an Ewing sarcoma (ES) oncoprotein with an interactome that we demonstrate to have multiple partners in spliceosomal complexes. We evaluate the effect of EWS-FLI1 on posttranscriptional gene regulation using both exon array and RNA-seq. Genes that potentially regulate oncogenesis, including CLK1, CASP3, PPFIBP1, and TERT, validate as alternatively spliced by EWS-FLI1. In a CLIP-seq experiment, we find that EWS-FLI1 RNA-binding motifs most frequently occur adjacent to intron-exon boundaries. EWS-FLI1 also alters splicing by directly binding to known splicing factors including DDX5, hnRNP K, and PRPF6. Reduction of EWS-FLI1 produces an isoform of γ-TERT that has increased telomerase activity compared with wild-type (WT) TERT. The small molecule YK-4-279 is an inhibitor of EWS-FLI1 oncogenic function that disrupts specific protein interactions, including helicases DDX5 and RNA helicase A (RHA) that alters RNA-splicing ratios. As such, YK-4-279 validates the splicing mechanism of EWS-FLI1, showing alternatively spliced gene patterns that significantly overlap with EWS-FLI1 reduction and WT human mesenchymal stem cells (hMSC). Exon array analysis of 75 ES patient samples shows similar isoform expression patterns to cell line models expressing EWS-FLI1, supporting the clinical relevance of our findings. These experiments establish systemic alternative splicing as an oncogenic process modulated by EWS-FLI1. EWS-FLI1 modulation of mRNA splicing may provide insight into the contribution of splicing toward oncogenesis, and, reciprocally, EWS-FLI1 interactions with splicing proteins may inform the splicing code.
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60
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Structure-function based molecular relationships in Ewing's sarcoma. BIOMED RESEARCH INTERNATIONAL 2015; 2015:798426. [PMID: 25688366 PMCID: PMC4320925 DOI: 10.1155/2015/798426] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 08/30/2014] [Accepted: 10/14/2014] [Indexed: 02/07/2023]
Abstract
Ewing's Sarcoma Oncogene (ews) on chromosome 22q12 is encoding a ubiquitously expressed RNA-binding protein (EWS) with unknown function that is target of tumor-specific chromosomal translocations in Ewing's sarcoma family of tumors. A model of transcription complex was proposed in which the heterodimer Rpb4/7 binds to EAD, connecting it to Core RNA Pol II. The DNA-binding domain, provided by EFP, is bound to the promoter. Rpb4/7 binds RNA, stabilizing the transcription complex. The complex Rpb4/7 can stabilize the preinitiation complexes by converting the conformation of RNA Pol II. EWS may change its conformation, so that NTD becomes accessible. Two different mechanisms of interaction between EWS and RNA Pol II are proposed: (I) an intermolecular EWS-EWS interaction between two molecules, pushing conformation from “closed” to “open” state, or (II) an intramolecular interaction inside the molecule of EWS, pushing conformation of the molecule from “closed” to “open” state. The modified forms of EWS may interact with Pol II subunits hsRpb5 and hsRpb7. The EWS and EFPs binding partners are described schematically in a model, an attempt to link the transcription with the splicing. The proposed model helps to understand the functional molecular interactions in cancer, to find new partners and ways to treat cancer.
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61
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Park JH, Hur W, Lee SB. Intricate Transcriptional Networks of Classical Brown and Beige Fat Cells. Front Endocrinol (Lausanne) 2015; 6:124. [PMID: 26322018 PMCID: PMC4533000 DOI: 10.3389/fendo.2015.00124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/24/2015] [Indexed: 02/05/2023] Open
Abstract
Brown adipocytes are a specialized cell type that is critical for adaptive thermogenesis, energy homeostasis, and metabolism. In response to cold, both classical brown fat and the newly identified "beige" or "brite" cells are activated by β-adrenergic signaling and catabolize stored lipids and carbohydrates to produce heat via UCP1. Once thought to be non-existent in adults, recent studies have discovered active classical brown and beige fat cells in humans, thus reinvigorating interest in brown and beige adipocytes. This review will focus on the newly discovered transcription factors and microRNAs that specify and orchestrate the classical brown and beige fat cell development.
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Affiliation(s)
- Jun Hong Park
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Wonhee Hur
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Sean Bong Lee
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, USA
- *Correspondence: Sean Bong Lee, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, 1700 Tulane Avenue Room 808, New Orleans, LA 70112, USA,
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62
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Park JH, Lee SB. An essential role for Ewing sarcoma gene (EWS) in early white adipogenesis. Obesity (Silver Spring) 2015; 23:138-44. [PMID: 25407167 DOI: 10.1002/oby.20934] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 09/23/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVE White adipose tissue is important for mammalian energy homeostasis and metabolism. It was previously demonstrated that Ewing sarcoma gene (EWS) is essential for early classical brown fat lineage determination, but its role in white adipocyte differentiation is not known. METHODS Mouse embryonic fibroblasts (MEFs) lacking Ews and shRNA-mediated silencing of Ews in 3T3L1 preadipocytes were used to investigate the role of EWS in adipogenesis. White fat differentiation was determined by analyzing the expression of key adipogenic genes and by Oil red O staining. RESULTS Following adipogenic stimulation, Ews expression arose rapidly in 3T3L1 cells during early induction period. Ews-null MEFs and 3T3L1 cells with reduced Ews expression failed to undergo adipogenesis. This was accompanied by significant reduction in the expression of critical early adipogenic regulators, Bmp2, Bmp4 (bone morphogenic protein 2 and 4), Cebpβ, and Cebpδ (CCAAT/enhancer binding protein β and δ). Complementation of recombinant BMP2 or BMP4 partially rescued adipogenesis in Ews-depleted 3T3L1 cells. CONCLUSIONS These results demonstrate that EWS is essential during the early steps of white adipocyte differentiation, at least in part through its regulation of BMP2 and BMP4 expression.
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Affiliation(s)
- Jun Hong Park
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, USA
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63
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Ishibashi J, Seale P. Functions of Prdm16 in thermogenic fat cells. Temperature (Austin) 2015; 2:65-72. [PMID: 27227007 PMCID: PMC4843880 DOI: 10.4161/23328940.2014.974444] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 10/06/2014] [Indexed: 12/04/2022] Open
Abstract
The PR-domain containing 16 (Prdm16) protein is a powerful inducer of the thermogenic phenotype in fat cells. In both developmental (brown) and induced (beige) thermogenic adipose tissue, Prdm16 has a critical role in maintaining proper tissue structure and function. It has roles throughout the course of differentiation, beginning with lineage determination activity in precursor cells, and continuing with coactivator functions that enable and maintain thermogenic gene expression. These abilities are primarily mediated by interactions with other adipogenic factors, suggesting that Prdm16 acts to coordinate the overall brown adipose phenotype. Mouse models have confirmed that thermogenic adipose depends upon Prdm16, and that this type of fat tissue provides substantial metabolic protection against the harmful effects of a high fat/high energy diet. Activation of Prdm16, therefore, holds promise for stimulating thermogenesis in fat cells to reduce human obesity and its complications.
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Affiliation(s)
- Jeff Ishibashi
- Institute for Diabetes, Obesity, & Metabolism; Department of Cell and Developmental Biology; Department of Genetics; Perelman School of Medicine; University of Pennsylvania; Philadelphia, PA USA
| | - Patrick Seale
- Institute for Diabetes, Obesity, & Metabolism; Department of Cell and Developmental Biology; Department of Genetics; Perelman School of Medicine; University of Pennsylvania; Philadelphia, PA USA
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64
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Etv1 and Ewsr1 cooperatively regulate limb mesenchymal Fgf10 expression in response to apical ectodermal ridge-derived fibroblast growth factor signal. Dev Biol 2014; 394:181-90. [DOI: 10.1016/j.ydbio.2014.07.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 07/02/2014] [Accepted: 07/30/2014] [Indexed: 11/21/2022]
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65
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Ebf2 is a selective marker of brown and beige adipogenic precursor cells. Proc Natl Acad Sci U S A 2014; 111:14466-71. [PMID: 25197048 DOI: 10.1073/pnas.1412685111] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Brown adipocytes and muscle and dorsal dermis descend from precursor cells in the dermomyotome, but the factors that regulate commitment to the brown adipose lineage are unknown. Here, we prospectively isolated and determined the molecular profile of embryonic brown preadipose cells. Brown adipogenic precursor activity in embryos was confined to platelet-derived growth factor α(+), myogenic factor 5(Cre)-lineage-marked cells. RNA-sequence analysis identified early B-cell factor 2 (Ebf2) as one of the most selectively expressed genes in this cell fraction. Importantly, Ebf2-expressing cells purified from Ebf2(GFP) embryos or brown fat tissue did not express myoblast or dermal cell markers and uniformly differentiated into brown adipocytes. Interestingly, Ebf2-expressing cells from white fat tissue in adult animals differentiated into brown-like (or beige) adipocytes. Loss of Ebf2 in brown preadipose cells reduced the expression levels of brown preadipose-signature genes, whereas ectopic Ebf2 expression in myoblasts activated brown preadipose-specific genes. Altogether, these results indicate that Ebf2 specifically marks and regulates the molecular profile of brown preadipose cells.
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66
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Kang HJ, Park JH, Chen W, Kang SI, Moroz K, Ladanyi M, Lee SB. EWS-WT1 oncoprotein activates neuronal reprogramming factor ASCL1 and promotes neural differentiation. Cancer Res 2014; 74:4526-35. [PMID: 24934812 DOI: 10.1158/0008-5472.can-13-3663] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The oncogenic fusion gene EWS-WT1 is the defining chromosomal translocation in desmoplastic small round-cell tumors (DSRCT), a rare but aggressive soft tissue sarcoma with a high rate of mortality. EWS-WT1 functions as an aberrant transcription factor that drives tumorigenesis, but the mechanistic basis for its pathogenic activity is not well understood. To address this question, we created a transgenic mouse strain that permits physiologic expression of EWS-WT1 under the native murine Ews promoter. EWS-WT1 expression led to a dramatic induction of many neuronal genes in embryonic fibroblasts and primary DSRCT, most notably the neural reprogramming factor ASCL1. Mechanistic analyses demonstrated that EWS-WT1 directly bound the proximal promoter of ASCL1, activating its transcription through multiple WT1-responsive elements. Conversely, EWS-WT1 silencing in DSRCT cells reduced ASCL1 expression and cell viability. Notably, exposure of DSRCT cells to neuronal induction media increased neural gene expression and induced neurite-like projections, both of which were abrogated by silencing EWS-WT1. Taken together, our findings reveal that EWS-WT1 can activate neural gene expression and direct partial neural differentiation via ASCL1, suggesting agents that promote neural differentiation might offer a novel therapeutic approach to treat DSRCT.
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Affiliation(s)
- Hong-Jun Kang
- Tulane University School of Medicine, Department of Pathology and Laboratory Medicine, New Orleans, Louisiana
| | - Jun Hong Park
- Tulane University School of Medicine, Department of Pathology and Laboratory Medicine, New Orleans, Louisiana
| | - WeiPing Chen
- Genomics Core Facility, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland
| | - Soo Im Kang
- Tulane University School of Medicine, Department of Pathology and Laboratory Medicine, New Orleans, Louisiana
| | - Krzysztof Moroz
- Tulane University School of Medicine, Department of Pathology and Laboratory Medicine, New Orleans, Louisiana
| | - Marc Ladanyi
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Sean Bong Lee
- Tulane University School of Medicine, Department of Pathology and Laboratory Medicine, New Orleans, Louisiana.
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Harms MJ, Ishibashi J, Wang W, Lim HW, Goyama S, Sato T, Kurokawa M, Won KJ, Seale P. Prdm16 is required for the maintenance of brown adipocyte identity and function in adult mice. Cell Metab 2014; 19:593-604. [PMID: 24703692 PMCID: PMC4012340 DOI: 10.1016/j.cmet.2014.03.007] [Citation(s) in RCA: 271] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 12/08/2013] [Accepted: 02/26/2014] [Indexed: 12/22/2022]
Abstract
Prdm16 is a transcription factor that regulates the thermogenic gene program in brown and beige adipocytes. However, whether Prdm16 is required for the development or physiological function of brown adipose tissue (BAT) in vivo has been unclear. By analyzing mice that selectively lacked Prdm16 in the brown adipose lineage, we found that Prdm16 was dispensable for embryonic BAT development. However, Prdm16 was required in young mice to suppress the expression of white-fat-selective genes in BAT through recruitment of the histone methyltransferase Ehmt1. Additionally, Prdm16 deficiency caused a severe adult-onset decline in the thermogenic character of interscapular BAT. This resulted in BAT dysfunction and cold sensitivity but did not predispose the animals to obesity. Interestingly, the loss of brown fat identity due to ablation of Prdm16 was accelerated by concurrent deletion of the closely related Prdm3 gene. Together, these results show that Prdm16 and Prdm3 control postnatal BAT identity and function.
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Affiliation(s)
- Matthew J Harms
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Jeff Ishibashi
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Wenshan Wang
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Hee-Woong Lim
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Susumu Goyama
- Department of Hematology and Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Tomohiko Sato
- Department of Hematology and Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Mineo Kurokawa
- Department of Hematology and Oncology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Kyoung-Jae Won
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Patrick Seale
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA.
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