151
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Choi SH, Park SK, Johnson BJ, Chung KY, Choi CW, Kim KH, Kim WY, Smith B. AMPKα, C/EBPβ, CPT1β, GPR43, PPARγ, and SCD Gene Expression in Single- and Co-cultured Bovine Satellite Cells and Intramuscular Preadipocytes Treated with Palmitic, Stearic, Oleic, and Linoleic Acid. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2015; 28:411-9. [PMID: 25656188 PMCID: PMC4341087 DOI: 10.5713/ajas.14.0598] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/02/2014] [Accepted: 10/09/2014] [Indexed: 01/28/2023]
Abstract
We previously demonstrated that bovine subcutaneous preadipocytes promote adipogenic gene expression in muscle satellite cells in a co-culture system. Herein we hypothesize that saturated fatty acids would promote adipogenic/lipogenic gene expression, whereas mono- and polyunsaturated fatty acids would have the opposite effect. Bovine semimembranosus satellite cells (BSC) and intramuscular preadipocytes (IPA) were isolated from crossbred steers and cultured with 10% fetal bovine serum (FBS)/Dulbecco’s Modified Eagle Medium (DMEM) and 1% antibiotics during the 3-d proliferation period. After proliferation, cells were treated for 3 d with 3% horse serum/DMEM (BSC) or 5% FBS/DMEM (IPA) with antibiotics. Media also contained 10 μg/mL insulin and 10 μg/mL pioglitazone. Subsequently, differentiating BSC and IPA were cultured in their respective media with 40 μM palmitic, stearic, oleic, or linoleic acid for 4 d. Finally, BSC and IPA were single- or co-cultured for an additional 2 h. All fatty acid treatments increased (p = 0.001) carnitine palmitoyltransferase-1 beta (CPT1β) gene expression, but the increase in CPT1β gene expression was especially pronounced in IPA incubated with palmitic and stearic acid (6- to 17- fold increases). Oleic and linoleic acid decreased (p = 0.001) stearoyl-CoA desaturase (SCD) gene expression over 80% in both BSC and IPA. Conversely, palmitic and stearic acid increased SCD gene expression three fold in co-cultured in IPA, and stearic acid increased AMPKα gene expression in single- and co-cultured BSC and IPA. Consistent with our hypothesis, saturated fatty acids, especially stearic acid, promoted adipogenic and lipogenic gene expression, whereas unsaturated fatty acids decreased expression of those genes associated with fatty acid metabolism.
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Affiliation(s)
- S H Choi
- Department of Animal Science, Texas Agricultural Experiment Station, Texas A&M University, College Station, TX 77843, USA ; Department of Animal Science, Chungbuk National University, Cheongju 361-763, Korea
| | - S K Park
- Department of Food Science and Technology, Sejong University, Seoul, 143-747, Korea
| | - B J Johnson
- Department of Animal and Food Science, Texas Tech University, Lubbock, TX 79409, USA
| | - K Y Chung
- Hanwoo Research Institute, National Institute of Animal Science, RDA, 232-950, Korea
| | - C W Choi
- Department of Animal Resources, Daegu University, Gyeongsan, 712-749, Korea
| | - K H Kim
- Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang 232-916, Korea . ; Institute of Green Bio Science & Technology, Seoul National University, Pyeongchang, 232-916, Korea
| | - W Y Kim
- Department of Animal Science, Chungbuk National University, Cheongju 361-763, Korea
| | - B Smith
- Department of Animal Science, Texas Agricultural Experiment Station, Texas A&M University, College Station, TX 77843, USA
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152
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Guo T, Zhu L, Tan J, Zhou X, Xiao L, Liu X, Wang B. Promoting effect of triterpenoid compound from Agrimonia pilosa Ledeb on preadipocytes differentiation via up-regulation of PPARγ expression. Pharmacogn Mag 2015; 11:219-25. [PMID: 25709235 PMCID: PMC4329626 DOI: 10.4103/0973-1296.149741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 04/25/2014] [Accepted: 01/21/2015] [Indexed: 01/05/2023] Open
Abstract
Background: Agrimonia Pilosa Ledeb (APL), a traditional Chinese medicine, has been reported a variety of biological activities, including treating T2DM. Objective: Triterpenoid compound (TC) was collected from APL. The aim of this study was to investigate the effects of TC on 3T3-L1 preadipocytes differentiation and genes related to differentiation and IR. Materials and Methods: Column chromatography was used to collect TC from ALP. 3T3-L1 cell differentiation was induced typically in the presence of various concentrations of TC or pioglitazone. Oil red O staining and measurement of intracellular TG content were performed on the seventh day of differentiation. Then quantitative polymerase chain reaction (Q-PCR) was used to test the expressions of three transcription factors (PPARγ, CCAAT enhancer binding protein-α (C/EBP-α), and sterol regulatory element-binding protein 1 (SREBP-1)) and the target genes of PPARγ including glucose transporter (GLUT4), lipoprotein lipase (LPL), fat acid binding protein (AP2), and adiponectin in 3T3-L1 cells. Results: At the concentration of 5, 25 and 125 μg/mL, TC significantly promoted triglyceride accumulation. Further study showed that TC could promote the expression of PPARγ, C/EBPα and ADD1/SREBP1 significantly at 125 μg/mL. As for downstream genes controlled by PPARγ, TC at 25 and 125 μg/mL could significantly promote the expression of GLUT4 and adiponectin. However, the expression of aP2 related to lipid metabolism and adiposity in the TC group was significantly lower than that in the pioglitazone group. Conclusion: TC could promote preadipocytes differentiation through activating PPARγ and downstream controlled genes. TC has the ideal insulin sensitization with lower adipogenic action than classical TZDs in vitro. So TC from Agrimonia Pilosa Ledeb has a good prospect as a natural drug for IR and T2DM.
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Affiliation(s)
- Tingwang Guo
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
| | - Liancai Zhu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
| | - Jun Tan
- School of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, China
| | - Xuemei Zhou
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
| | - Ling Xiao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
| | - Xi Liu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
| | - Bochu Wang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
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153
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Eisenstein A, Carroll SH, Johnston-Cox H, Farb M, Gokce N, Ravid K. An adenosine receptor-Krüppel-like factor 4 protein axis inhibits adipogenesis. J Biol Chem 2015; 289:21071-81. [PMID: 24928509 DOI: 10.1074/jbc.m114.566406] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Adipogenesis represents a key process in adipose tissue development and remodeling, including during obesity. Exploring the regulation of adipogenesis by extracellular ligands is fundamental to our understanding of this process. Adenosine, an extracellular nucleoside signaling molecule found in adipose tissue depots, acts on adenosine receptors. Here we report that, among these receptors, the A2b adenosine receptor (A2bAR) is highly expressed in adipocyte progenitors. Activation of the A2bAR potently inhibits differentiation of mouse stromal vascular cells into adipocytes, whereas A2bAR knockdown stimulates adipogenesis. The A2bAR inhibits differentiation through a novel signaling cascade involving sustained expression of Krüppel-like factor 4 (KLF4), a regulator of stem cell maintenance. Knockdown of KLF4 ablates the ability of the A2bAR to inhibit differentiation. A2bAR activation also inhibits adipogenesis in a human primary preadipocyte culture system. We analyzed the A2bARKLF4 axis in adipose tissue of obese subjects and, intriguingly, found a strong correlation between A2bAR and KLF4 expression in both subcutaneous and visceral human fat. Hence, our study implicates the A2bAR as a regulator of adipocyte differentiation and the A2bAR-KLF4 axis as a potentially significant modulator of adipose biology.
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154
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Schwind L, Zimmer AD, Götz C, Montenarh M. CK2 phosphorylation of C/EBPδ regulates its transcription factor activity. Int J Biochem Cell Biol 2015; 61:81-9. [PMID: 25680545 DOI: 10.1016/j.biocel.2015.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/26/2015] [Accepted: 02/03/2015] [Indexed: 01/25/2023]
Abstract
Protein kinase CK2 plays an essential role in cell viability in lower and higher eukaryotes. As a global regulator it phosphorylates and thereby regulates a broad array of cellular targets including a large number of transcription factors. Here, we have identified the CCAAT/enhancer binding protein δ (C/EBPδ) as a new substrate for CK2. Using point mutants of C/EBPδ the major phosphorylation site for CK2 was mapped to serine 57, which is located within the transactivation domain of C/EBPδ. For proper functioning as a transcription factor C/EBPδ has to be translocated into the nucleus where it forms heterodimers with other members of the C/EBP family of proteins and ATF4. Here, we found that CK2 phosphorylation does neither influence the subcellular localization of C/EBPδ nor its interaction with C/EBPβ, but rather does CK2 phosphorylation modulate the transcriptional activity of C/EBPδ. Moreover, we found that CK2 bound to C/EBPδ, which might help to target CK2 to the transcriptional machinery where it can phosphorylate other transcription factors or co-activators.
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Affiliation(s)
- Lisa Schwind
- Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany
| | - Andreas D Zimmer
- Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany
| | - Mathias Montenarh
- Medical Biochemistry and Molecular Biology, Saarland University, Building 44, D-66424 Homburg, Germany.
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155
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Contador D, Ezquer F, Espinosa M, Arango-Rodriguez M, Puebla C, Sobrevia L, Conget P. Dexamethasone and rosiglitazone are sufficient and necessary for producing functional adipocytes from mesenchymal stem cells. Exp Biol Med (Maywood) 2015; 240:1235-46. [PMID: 25595190 DOI: 10.1177/1535370214566565] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 11/17/2014] [Indexed: 12/13/2022] Open
Abstract
The final product of adipogenesis is a functional adipocyte. This mature cell acquires the necessary machinery for lipid metabolism, loses its proliferation potential, increases its insulin sensitivity, and secretes adipokines. Multipotent mesechymal stromal cells have been recognized as a source of adipocytes both in vivo and in vitro. The in vitro adipogenic differentiation of human MSC (hMSC) has been induced up to now by using a complex stimulus which includes dexamethasone, 3-isobutyl-1-methylxanthine, indomethacin, and insulin (a classical cocktail) and evaluated according to morphological changes. The present work was aimed at demonstrating that the simultaneous activation of dexamethasone's canonical signaling pathways, through the glucocorticoid receptor and CCAAT-enhancer-binding proteins (C/EBPs) and rosiglitazone through peroxisome proliferator-activated receptor gamma (PPAR-gamma) is sufficient yet necessary for inducing hMSC adipogenic differentiation. It was also ascertained that hMSC exposed just to dexamethasone and rosiglitazone (D&R) differentiated into cells which accumulated neutral lipid droplets, expressed C/EBP-alpha, PPAR-gamma, aP2, lipoprotein lipase, acyl-CoA synthetase, phosphoenolpyruvate carboxykinase, adiponectin, and leptin genes but did not proliferate. Glucose uptake was dose dependent on insulin stimulus and high levels of adipokines were secreted (i.e. displaying not only the morphology but also expressing mature adipocytes' specific genes and functional characteristics). This work has demonstrated that (i) the activating C/EBPs and PPAR-gamma signaling pathways were sufficient to induce adipogenic differentiation from hMSC, (ii) D&R producing functional adipocytes from hMSC, (iii) D&R induce adipogenic differentiation from mammalian MSC (including those which are refractory to classical adipogenic differentiation stimuli). D&R would thus seem to be a useful tool for MSC characterization, studying adipogenesis pathways and producing functional adipocytes.
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Affiliation(s)
- David Contador
- Center for Regenerative Medicine, School of Medicine, Clínica Alemana Universidad del Desarrollo, Santiago 7710162, Chile
| | - Fernando Ezquer
- Center for Regenerative Medicine, School of Medicine, Clínica Alemana Universidad del Desarrollo, Santiago 7710162, Chile
| | - Maximiliano Espinosa
- Center for Regenerative Medicine, School of Medicine, Clínica Alemana Universidad del Desarrollo, Santiago 7710162, Chile
| | - Martha Arango-Rodriguez
- Center for Regenerative Medicine, School of Medicine, Clínica Alemana Universidad del Desarrollo, Santiago 7710162, Chile
| | - Carlos Puebla
- Cellular and Molecular Physiology Laboratory, Obstetrics and Gynecology Division, Faculty of Medicine, P. Universidad Católica de Chile, Santiago 8330024, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory, Obstetrics and Gynecology Division, Faculty of Medicine, P. Universidad Católica de Chile, Santiago 8330024, Chile
| | - Paulette Conget
- Center for Regenerative Medicine, School of Medicine, Clínica Alemana Universidad del Desarrollo, Santiago 7710162, Chile
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156
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Ko CY, Chang WC, Wang JM. Biological roles of CCAAT/Enhancer-binding protein delta during inflammation. J Biomed Sci 2015; 22:6. [PMID: 25591788 PMCID: PMC4318212 DOI: 10.1186/s12929-014-0110-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/25/2014] [Indexed: 01/13/2023] Open
Abstract
CCAAT/enhancer-binding protein delta (CEBPD) belongs to the CCAAT/enhancer-binding protein family, and these proteins function as transcription factors in many biological processes, including cell differentiation, motility, growth arrest, proliferation, cell death, metabolism and immune responses. The functional diversity of CEBPD depends, in part, on the cell type and cellular context, which indicates that CEBPD could interpret a variety of cues to adjust cellular responses in specific situations. Here, we review the regulation of the CEBPD gene and its function in response to inflammatory stimuli. We also address its effects in inflammation-related diseases through a discussion of its recently discovered downstream targets. Regarding to the previous discoveries and new insights in inflammation-associated diseases, suggesting CEBPD could also be a central gene in inflammation. Importantly, the results of this study indicate that the investigation of CEBPD could open a new avenue to help better understand the inflammatory response.
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Affiliation(s)
- Chiung-Yuan Ko
- Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan. .,Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 11031, Taiwan.
| | - Wen-Chang Chang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 11031, Taiwan.
| | - Ju-Ming Wang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 11031, Taiwan. .,Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, 70101, Taiwan. .,Infectious Disease and Signaling Research Center, National Cheng Kung University, Tainan, 70101, Taiwan. .,Center of Molecular Inflammation, National Cheng Kung University, Tainan, 70101, Taiwan.
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157
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Abstract
Glucocorticoids (GCs) and their cognate, intracellular receptor, the glucocorticoid receptor (GR) have been characterized as critical checkpoints in the hormonal control of energy homeostasis in mammals. Whereas physiological levels of GCs are required for proper metabolic control, aberrant GC action has been linked to a variety of severe metabolic diseases, including type 2 diabetes and obesity. As a member of the nuclear receptor superfamily of transcription factors, the GR translocates into the cell nucleus upon GC binding where it serves as a transcriptional regulator of distinct GC-responsive target genes that are in many cases associated with lipid regulatory pathways and thereby intricately control both physiological and pathophysiological systemic lipid homeostasis. Thus, this chapter focuses on the current knowledge of GC/GR function in lipid handling and its implications for systemic metabolic dysfunction.
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158
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MYC is an early response regulator of human adipogenesis in adipose stem cells. PLoS One 2014; 9:e114133. [PMID: 25437437 PMCID: PMC4250176 DOI: 10.1371/journal.pone.0114133] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 11/02/2014] [Indexed: 12/13/2022] Open
Abstract
Adipose stem cell (ASC) differentiation is necessary for the proper maintenance and function of adipose tissue. The procurement and characterization of multipotent ASCs has enabled investigation into the molecular determinants driving human adipogenesis. Here, the transcription factor MYC was identified as a significant regulator of ASC differentiation. Expression of MYC transcript and protein was found to accumulate during the initial course of differentiation. Loss-of-function analysis using siRNA mediated knockdown of MYC demonstrated inhibition of hormonally stimulated adipogenesis. MYC exhibited an early and sustained expression pattern that preceded down regulation of key suppressor genes, as well as induction of transcriptional and functional effectors. Glucocorticoid stimulation was identified as a necessary component for MYC induction and was found to impact adipogenesis in a concentration-dependent manner. Global gene expression analysis of MYC knockdown in ASC enriched for functional pathways related to cell adhesion, cytoskeletal remodeling, and transcriptional components of adipogenesis. These results identify a functional role for MYC in promotion of multipotent ASC to the adipogenic lineage.
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159
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Kuzmochka C, Abdou HS, Haché RJG, Atlas E. Inactivation of histone deacetylase 1 (HDAC1) but not HDAC2 is required for the glucocorticoid-dependent CCAAT/enhancer-binding protein α (C/EBPα) expression and preadipocyte differentiation. Endocrinology 2014; 155:4762-73. [PMID: 25203139 DOI: 10.1210/en.2014-1565] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Several drugs currently used in the management of mood disorders, epilepsy (ie, valproic acid), or the control of inflammation (ie, corticosteroids) have been shown to promote visceral obesity in humans by increasing the number of newly formed adipocytes. Valproic acid is classified as a nonspecific histone deacetylase (HDAC) inhibitor, along with trichostatin A and butyric acid. In vitro experiments have demonstrated that such molecules greatly enhance the rate of preadipocyte differentiation, similarly to the effect of corticosteroids. The glucocorticoid receptor stimulates adipogenesis in part by enhancing the transcription of C/ebpa through the titration, and subsequent degradation, of HDAC1 from the C/ebpα promoter. There is, however, controversy in the literature as to the role of HDACs during adipogenesis. In this study, we sought to demonstrate, using 2 different strategies, the definite role of HDAC1 in adipogenesis. By using small interference RNA-mediated knockdown of HDAC1 and by generating an enzymatically inactive HDAC1D181A by site-directed mutagenesis, we were able to show that HDAC1, but not HDAC2, suppresses glucocorticoid receptor-potentiated preadipocyte differentiation by decreasing CCAAT/enhancer-binding protein (C/ebp)α and Pparγ expression levels at the onset of differentiation. Finally, we demonstrate that HDAC1D181A acts as a dominant negative mutant of HDAC1 during adipogenesis by modulating C/EBPβ transcriptional activity on the C/ebpα promoter.
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Affiliation(s)
- Claire Kuzmochka
- Northern Ontario School of Medicine, Ontario, Canada ON POM Reproduction, Mother and Youth Health (H.-S.A.), CHUQ Research Centre, Quebec city, Quebec, Canada G1R2J6; Environmental Health Science and Research Bureau (E.A.), Health Canada, Ottawa, Ontario, Canada M3J1P3; and York University (R.J.G.H.), Toronto, Ontario, Canada K1A0K9
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160
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Wang X, Yang P, Liu J, Wu H, Yu W, Zhang T, Fu H, Liu Y, Hai C. RARγ-C-Fos-PPARγ2 signaling rather than ROS generation is critical for all-trans retinoic acid-inhibited adipocyte differentiation. Biochimie 2014; 106:121-30. [PMID: 25173565 DOI: 10.1016/j.biochi.2014.08.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/19/2014] [Indexed: 11/18/2022]
Abstract
Obesity has become a worldwide public health problem, which is mainly determined by excess energy intake and adipose tissue expansion. Adipose tissue expansion can occur through hyperplasia (adipocyte differentiation) or hypertrophy. Retinoic acid was shown to inhibit adipocyte differentiation. However, the molecular mechanism is unclear. In the study, we found that all-trans-retinoic acid (ATRA) inhibited 3T3-L1 adipocyte differentiation. We did not observe significant apoptosis in differentiated adipocytes treated by ATRA. ATRA increased ROS generation and disturbed redox balance. However, antioxidant treatment did not ameliorate the reduction of lipid accumulation induced by ATRA, indicating that ROS generation was not involved in ATRA-inhibited adipocyte differentiation. ATRA reduced C/EBPα, PPARγ and its target gene expression. In the presence of ATRA, retinoic acid receptor (RAR) α/γ expression was increased. Inhibition of RARγ, but not RARα, blocked ATRA-induced reduction of PPARγ2 expression. ATRA induced a profound interaction between RARγ and C-Fos protein, reflected by Co-IP results. C-Fos was found to exhibit a differentiation-dependent DNA binding activity to PPARγ2 promoter. RARγ inhibitor significantly suppressed ATRA-inhibited DNA binding activity of C-Fos to PPARγ2 promoter, indicating that downregulation of C-Fos activity mediated activation of RARγ-exerted reduction of PPARγ2 expression and thus inhibition of adipocyte differentiation induced by ATRA. Taken together, these data demonstrates that RARγ-C-Fos-PPARγ2 signaling rather than ROS generation is critical for ATRA-inhibited adipocyte differentiation.
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Affiliation(s)
- Xin Wang
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China.
| | - Peng Yang
- Department of Health Statistics, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | - Jiangzheng Liu
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | - Hao Wu
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | - Weihua Yu
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | - Tao Zhang
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | - Han Fu
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | - Ying Liu
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China
| | - Chunxu Hai
- Department of Toxicology, Shaanxi Key Lab of Free Radical Biology and Medicine, The Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an 710032, China.
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161
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Chen X, Feng Y, Yang WJ, Shu G, Jiang QY, Wang XQ. Effects of dietary thiazolidinedione supplementation on growth performance, intramuscular fat and related genes mRNA abundance in the longissimus dorsi muscle of finishing pigs. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2014; 26:1012-20. [PMID: 25049880 PMCID: PMC4093500 DOI: 10.5713/ajas.2012.12722] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/26/2013] [Accepted: 02/01/2013] [Indexed: 02/08/2023]
Abstract
The objective of this study was to investigate the effect of dietary supplementation with thiazolidinedione (TZD) on growth performance and meat quality of finishing pigs. In Experiment 1, 80 castrated finishing pigs (Large White×Landrace, BW = 54.34 kg) were randomly assigned to 2 treatments with 5 replicates of 8 pigs each. The experimental pigs in the 2 groups were respectively fed with a diet with or without a TZD supplementation (15 mg/kg). In Experiment 2, 80 castrated finishing pigs (Large White×Landrace, BW = 71.46 kg) were divided into 2 treatments as designed in Experiment 1, moreover, carcass evaluations were performed. The results from Experiment 1 showed that TZD supplementation could significantly decreased the average daily feed intake (ADFI) (p<0.05) during 0 to 28 d, without impairing the average daily gain (ADG) (p>0.05). In Experiment 2, the ADG was significantly increased by TZD supplementation during 14 to 28 d and 0 to 28 d (p<0.05) and the feed:gain ratio (F:G) was significantly decreased by TZD supplementation during 0 to 28 d (p<0.05). Compared with the control group, TZD group had significantly higher serum triglyceride (TG) concentration at 28h and serum high-density lipoprotein (HDL) levels at 14 d (p<0.05). Moreover, there was an apparent improvement in the marbling score (p<0.10) and intramuscular fat (IMF) content (p<0.10) of the longissimus dorsi muscle in pigs treated by TZD supplementation. Real-time RT-PCR analyses demonstrated that pigs of TZD group had higher mRNA abundance of PPARγ coactivator 1 (PGC-1) (p<0.05) and fatty acid-binding protein 3 (FABP3) (p<0.05) than pigs of control group. Taken together, these results suggested that dietary TZD supplementation could improve growth performance and increase the IMF content of finishing pigs through regulating the serum parameters and genes mRNA abundance involved in fat metabolism.
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Affiliation(s)
- X Chen
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, Department of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Y Feng
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, Department of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - W J Yang
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, Department of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - G Shu
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, Department of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Q Y Jiang
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, Department of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - X Q Wang
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, Department of Animal Science, South China Agricultural University, Guangzhou, 510642, China
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162
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Lessard J, Tchernof A. Interaction of the glucocorticoid and androgen receptors in adipogenesis. ACTA ACUST UNITED AC 2014; 19:1079-80. [PMID: 22999873 DOI: 10.1016/j.chembiol.2012.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Glucocorticoids and androgens are important regulators of adipose tissue function. A new study by Hartig et al. in this issue of Chemistry & Biology provides relevant information regarding androgen receptor activity and its link to glucocorticoid action in human adipocytes during the process of preadipocyte differentiation.
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163
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Atlas E, Pope L, Wade MG, Kawata A, Boudreau A, Boucher JG. Bisphenol A increases aP2 expression in 3T3L1 by enhancing the transcriptional activity of nuclear receptors at the promoter. Adipocyte 2014; 3:170-9. [PMID: 25068083 PMCID: PMC4110093 DOI: 10.4161/adip.28436] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 01/22/2023] Open
Abstract
Environmental pollutants, such as bisphenol A (BPA), have the potential to affect the differentiation processes and the biology of the adipose tissue. The 3T3-L1 model is one of the murine cell models used extensively for the investigation of the molecular events that govern the differentiation of adipocytes from a committed preadipocyte to a mature, lipid laden adipocyte. Most of the studies investigating the effects of BPA on preadipocyte differentiation have investigated the effects of this chemical in the presence of an optimal differentiation cocktail containing high concentrations of the synthetic glucocorticoid dexamethasone, conditions that result in 90% to 100% of differentiated adipocytes. Our studies employed the 3T3-L1 cell model in the absence of exogenous glucocorticoids. We show that BPA is able to increase the differentiation of the 3T3-L1 cells under these conditions. Furthermore, the effect of BPA was observed in the absence of the synthetic glucocorticoid (dexamethasone), a hormone known to be required for the differentiation of the 3T3-L1 cells. In addition, BPA upregulated the mRNA expression and protein levels of the terminal marker of adipogenesis the fatty acid binding protein (aP2) in these cells. Interestingly, the known modulators of adipogenesis such as the peroxisome proliferator-activated receptor (PPAR) γ or CCAAT enhancer binding protein (C/EBP) α were not elevated at the mRNA or protein level in response to BPA. Furthermore, BPA upregulated the expression levels of the marker of adipogenesis aP2, through an effect on the transcriptional activity of C/EBPδ and the glucocorticoid receptor (GR) at its promoter.
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164
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Zhao P, Stephens JM. Identification of STAT target genes in adipocytes. JAKSTAT 2014; 2:e23092. [PMID: 24058802 PMCID: PMC3710315 DOI: 10.4161/jkst.23092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/02/2012] [Accepted: 12/03/2012] [Indexed: 02/08/2023] Open
Abstract
Adipocytes play important roles in lipid storage, energy homeostasis and whole body insulin sensitivity. Studies in the last two decades have identified the hormones and cytokines that activate specific STATs in adipocytes in vitro and in vivo. Five of the seven STAT family members are expressed in adipocyte (STATs 1, 3, 5A, 5B and 6). Many transcription factors, including STATs, have been shown to play an important role in adipose tissue development and function. This review will summarize the importance of adipocytes, indicate the cytokines and hormones that utilize the JAK-STAT signaling pathway in fat cells and focus on the identification of STAT target genes in mature adipocytes. To date, specific target genes have been identified for STATs, 1, 5A and 5B, but not for STATs 3 and 6.
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Affiliation(s)
- Peng Zhao
- Department of Biological Sciences; Louisiana State University; Baton Rouge, LA USA ; Adipocyte Biology Lab; Pennington Biomedical Research Center; Baton Rouge, LA USA
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165
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p38 MAPK-inhibited dendritic cells induce superior antitumour immune responses and overcome regulatory T-cell-mediated immunosuppression. Nat Commun 2014; 5:4229. [PMID: 24957461 DOI: 10.1038/ncomms5229] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 05/27/2014] [Indexed: 01/06/2023] Open
Abstract
Dendritic cell (DC)-based cancer immunotherapy is a promising method, but so far has demonstrated limited clinical benefits. Regulatory T cells (Tregs) represent a major obstacle to cancer immunotherapy approaches. Here we show that inhibiting p38 MAPK during DC differentiation enables DCs to activate tumour-specific effector T cells (Teff), inhibiting the conversion of Treg and compromising Treg inhibitory effects on Teff. Inhibition of p38 MAPK in DCs lowers expression of PPARγ, activating p50 and upregulating OX40L expression in DCs. OX40L/OX40 interactions between DCs and Teff and/or Treg are critical for priming effective and therapeutic antitumour responses. Similarly, p38 MAPK inhibition also augments the T-cell stimulatory capacity of human monocyte-derived DCs in the presence of Treg. These findings contribute to ongoing efforts to improve DC-based immunotherapy in human cancers.
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166
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Abstract
Maintaining proper energy balance in mammals entails intimate crosstalk between various tissues and organs. These inter-organ communications are mediated, to a great extent, by secreted hormones that circulate in blood. Regulation of the complex metabolic networks by secreted hormones (e.g., insulin, glucagon, leptin, adiponectin, FGF21) constitutes an important mechanism governing the integrated control of whole-body metabolism. Disruption of hormone-mediated metabolic circuits frequently results in dysregulated energy metabolism and pathology. As part of an effort to identify novel metabolic hormones, we recently characterized a highly conserved family of 15 secreted proteins, the C1q/TNF-related proteins (CTRP1-15). While related to adiponectin in sequence and structural organization, each CTRP has its own unique tissue expression profile and non-redundant function in regulating sugar and/or fat metabolism. Here, we summarize the current understanding of the physiological functions of CTRPs, emphasizing their metabolic roles. Future studies using gain-of-function and loss-of-function mouse models will provide greater mechanistic insights into the critical role CTRPs play in regulating systemic energy homeostasis.
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Affiliation(s)
- Marcus M Seldin
- Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
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167
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Lee JE, Ge K. Transcriptional and epigenetic regulation of PPARγ expression during adipogenesis. Cell Biosci 2014; 4:29. [PMID: 24904744 PMCID: PMC4046494 DOI: 10.1186/2045-3701-4-29] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 05/16/2014] [Indexed: 12/25/2022] Open
Abstract
The nuclear receptor PPARγ is a master regulator of adipogenesis. PPARγ is highly expressed in adipose tissues and its expression is markedly induced during adipogenesis. In this review, we describe the current knowledge, as well as future directions, on transcriptional and epigenetic regulation of PPARγ expression during adipogenesis. Investigating the molecular mechanisms that control PPARγ expression during adipogenesis is critical for understanding the development of white and brown adipose tissues, as well as pathological conditions such as obesity and diabetes. The robust induction of PPARγ expression during adipogenesis also serves as an excellent model system for studying transcriptional and epigenetic regulation of cell-type-specific gene expression.
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Affiliation(s)
- Ji-Eun Lee
- Adipocyte Biology and Gene Regulation Section, Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kai Ge
- Adipocyte Biology and Gene Regulation Section, Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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168
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Palacios-Ortega S, Varela-Guruceaga M, Milagro FI, Martínez JA, de Miguel C. Expression of Caveolin 1 is enhanced by DNA demethylation during adipocyte differentiation. status of insulin signaling. PLoS One 2014; 9:e95100. [PMID: 24751908 PMCID: PMC3994010 DOI: 10.1371/journal.pone.0095100] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/23/2014] [Indexed: 12/14/2022] Open
Abstract
Caveolin 1 (Cav-1) is an essential constituent of adipocyte caveolae which binds the beta subunit of the insulin receptor (IR) and is implicated in the regulation of insulin signaling. We have found that, during adipocyte differentiation of 3T3-L1 cells the promoter, exon 1 and first intron of the Cav-1 gene undergo a demethylation process that is accompanied by a strong induction of Cav-1 expression, indicating that epigenetic mechanisms must have a pivotal role in this differentiation process. Furthermore, IR, PKB-Akt and Glut-4 expression are also increased during the differentiation process suggesting a coordinated regulation with Cav-1. Activation of Cav-1 protein by phosphorylation arises during the differentiation process, yet in fully mature adipocytes insulin is no longer able to significantly increase Cav-1 phosphorylation. However, these long-term differentiated cells are still able to respond adequately to insulin, increasing IR and PKB-Akt phosphorylation and glucose uptake. The activation of Cav-1 during the adipocyte differentiation process could facilitate the maintenance of insulin sensitivity by these fully mature adipocytes isolated from additional external stimuli. However, under the influence of physiological conditions associated to obesity, such as chronic inflammation and hypoxia, insulin sensitivity would finally be compromised.
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Affiliation(s)
| | | | - Fermín Ignacio Milagro
- Department of Nutrition Food Science and Physiology, University of Navarra, Pamplona, Spain
- Physiopathology of Obesity and Nutrition CIBERobn, Carlos III Health Research Institute, Madrid, Spain
| | - José Alfredo Martínez
- Department of Nutrition Food Science and Physiology, University of Navarra, Pamplona, Spain
- Physiopathology of Obesity and Nutrition CIBERobn, Carlos III Health Research Institute, Madrid, Spain
| | - Carlos de Miguel
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain
- Physiopathology of Obesity and Nutrition CIBERobn, Carlos III Health Research Institute, Madrid, Spain
- * E-mail:
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169
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Park JS, Bae SJ, Choi SW, Son YH, Park SB, Rhee SD, Kim HY, Jung WH, Kang SK, Ahn JH, Kim SH, Kim KY. A novel 11β-HSD1 inhibitor improves diabesity and osteoblast differentiation. J Mol Endocrinol 2014; 52:191-202. [PMID: 24444497 DOI: 10.1530/jme-13-0177] [Citation(s) in RCA: 17] [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] [Indexed: 01/06/2023]
Abstract
Selective inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) have considerable potential as treatment for osteoporosis as well as metabolic syndrome including type 2 diabetes mellitus. Here, we investigated the anti-diabetic, anti-adipogenic, and anti-osteoporotic activity of KR-67500, as a novel selective 11β-HSD1 inhibitor. Cellular 11β-HSD1 activity was tested based on a homogeneous time-resolved fluorescence method. Oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) levels were measured in diet-induced obese (DIO)-C57BL/6 mice administered KR-67500 (50 mg/kg per day, p.o.) for 28 days and, additionally, its anti-diabetic effect was evaluated by OGTT and ITT. The in vitro anti-adipogenic effect of KR-67500 was determined by Oil Red O Staining. The in vitro anti-osteoporotic activity of KR-67500 was evaluated using bone morphogenetic protein 2 (BMP2)-induced osteoblast differentiation and receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation model systems. KR-67500 improved the in vivo glucose tolerance and insulin sensitivity in DIO-C57BL/6 mice. KR-67500 suppressed cortisone-induced differentiation of 3T3-L1 cells into adipocytes. KR-67500 enhanced BMP2-induced osteoblastogenesis in C2C12 cells and inhibited RANKL-induced osteoclastogenesis in mouse bone marrow-derived macrophages. KR-67500, a new selective 11β-HSD1 inhibitor, may provide a new therapeutic window in the prevention and/or treatment of type 2 diabetes, obesity, and/or osteoporosis.
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Affiliation(s)
- Ji Seon Park
- Division of Drug Discovery Research, Korea Research Institute of Chemical Technology, PO Box 107, Yuseong-gu, Daejeon 305-600, Republic of Korea Division of Life and Pharmaceutical Sciences and Center for Cell Signaling and Drug Discovery Research, College of Pharmacy, Ewha Woman's University, Sedaemoon-gu, Seoul 120-750, Republic of Korea Laboratory of Translational Therapeutics, Korea Research Institute of Chemical Technology, Pharmacology Research Center, PO Box 107, Yuseong-gu, Daejeon 305-600, Republic of Korea Department of Toxicology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea Department of Medicinal and Pharmaceutical Chemistry, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 305-333, Republic of Korea
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170
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Abstract
Estrogen sulfotransferase (EST/SULT1E1) is known to catalyze the sulfoconjugation and deactivation of estrogens. The goal of this study is to determine whether and how EST plays a role in human adipogenesis. By using human primary adipose-derived stem cells (ASCs) and whole-fat tissues from the abdominal subcutaneous fat of obese and nonobese subjects, we showed that the expression of EST was low in preadipocytes but increased upon differentiation. Overexpression and knockdown of EST in ASCs promoted and inhibited differentiation, respectively. The proadipogenic activity of EST in humans was opposite to the antiadipogenic effect of the same enzyme in rodents. Mechanistically, EST promoted adipogenesis by deactivating estrogens. The proadipogenic effect of EST can be recapitulated by using an estrogen receptor (ER) antagonist or ERα knockdown. In contrast, activation of ER in ASCs inhibited adipogenesis by decreasing the recruitment of the adipogenic peroxisome proliferator-activated receptor γ (PPARγ) onto its target gene promoters, whereas ER antagonism increased the recruitment of PPARγ to its target gene promoters. Linear regression analysis revealed a positive correlation between the expression of EST and body mass index (BMI), as well as a negative correlation between ERα expression and BMI. We conclude that EST is a proadipogenic factor which may serve as a druggable target to inhibit the turnover and accumulation of adipocytes in obese patients.
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171
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Eisenstein A, Ravid K. G protein-coupled receptors and adipogenesis: a focus on adenosine receptors. J Cell Physiol 2014; 229:414-21. [PMID: 24114647 DOI: 10.1002/jcp.24473] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/12/2013] [Indexed: 12/20/2022]
Abstract
G-protein coupled receptors (GPCRs) are a large family of proteins that coordinate extracellular signals to produce physiologic outcomes. Adenosine receptors (AR) are one class of GPCRs that have been shown to regulate functions as diverse as inflammation, blood flow, and cellular differentiation. Adenosine signals through four GPCRs that either inhibit (A1AR and A3AR) or activate (A2aAR and A2bAR) adenylyl cyclase. This review will focus on the role of GPCRs, and in particular, adenosine receptors, in adipogenesis. Preadipocytes differentiate to mature adipocytes as the adipose tissue expands to compensate for the consumption of excess nutrients. These newly generated adipocytes contribute to maintaining metabolic homeostasis. Understanding the key drivers of this differentiation process can aid the development of therapeutics to combat the growing obesity epidemic and associated metabolic consequences. Although much literature has covered the transcriptional events that culminate in the formation of an adipocyte, less focus has been on receptor-mediated extracellular signals that direct this process. This review will highlight GPCRs and their downstream messengers as significant players controlling adipocyte differentiation.
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Affiliation(s)
- Anna Eisenstein
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts; Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts
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172
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Lim DC, Pack AI. Obstructive sleep apnea and cognitive impairment: addressing the blood-brain barrier. Sleep Med Rev 2014; 18:35-48. [PMID: 23541562 PMCID: PMC3758447 DOI: 10.1016/j.smrv.2012.12.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/21/2012] [Accepted: 12/24/2012] [Indexed: 12/14/2022]
Abstract
Increasing data support a connection between obstructive sleep apnea (OSA) and cognitive impairment but a causal link has yet to be established. Although neuronal loss has been linked to cognitive impairment, emerging theories propose that changes in synaptic plasticity can cause cognitive impairment. Studies demonstrate that disruption to the blood-brain barrier (BBB), which is uniquely structured to tightly maintain homeostasis inside the brain, leads to changes in the brain's microenvironment and affects synaptic plasticity. Cyclical intermittent hypoxia is a stressor that could disrupt the BBB via molecular responses already known to occur in either OSA patients or animal models of intermittent hypoxia. However, we do not yet know if or how intermittent hypoxia can cause cognitive impairment by mechanisms operating at the BBB. Therefore, we propose that initially, adaptive homeostatic responses at the BBB occur in response to increased oxygen and nutrient demand, specifically through regulation of influx and efflux BBB transporters that alter microvessel permeability. We further hypothesize that although these responses are initially adaptive, these changes in BBB transporters can have long-term consequences that disrupt the brain's microenvironment and alter synaptic plasticity leading to cognitive impairment.
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Affiliation(s)
- Diane C Lim
- Department of Medicine, Division of Sleep Medicine, and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA 19104, USA.
| | - Allan I Pack
- Department of Medicine, Division of Sleep Medicine, and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA 19104, USA.
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173
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Abstract
The family of inhibitor of differentiation (Id) proteins is a group of evolutionarily conserved molecules, which play important regulatory roles in organisms ranging from Drosophila to humans. Id proteins are small polypeptides harboring a helix-loop-helix (HLH) motif, which are best known to mediate dimerization with other basic HLH proteins, primarily E proteins. Because Id proteins do not possess the basic amino acids adjacent to the HLH motif necessary for DNA binding, Id proteins inhibit the function of E protein homodimers, as well as heterodimers between E proteins and tissue-specific bHLH proteins. However, Id proteins have also been shown to have E protein-independent functions. The Id genes are broadly but differentially expressed in a variety of cell types. Transcription of the Id genes is controlled by transcription factors such as C/EBPβ and Egr as well as by signaling pathways triggered by different stimuli, which include bone morphogenic proteins, cytokines, and ligands of T cell receptors. In general, Id proteins are capable of inhibiting the differentiation of progenitors of different cell types, promoting cell-cycle progression, delaying cellular senescence, and facilitating cell migration. These properties of Id proteins enable them to play significant roles in stem cell maintenance, vasculogenesis, tumorigenesis and metastasis, the development of the immune system, and energy metabolism. In this review, we intend to highlight the current understanding of the function of Id proteins and discuss gaps in our knowledge about the mechanisms whereby Id proteins exert their diverse effects in multiple cellular processes.
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Affiliation(s)
- Flora Ling
- Immunobiology Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Bin Kang
- Immunobiology Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Xiao-Hong Sun
- Immunobiology Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.
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174
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Suppression of PPARγ through MKRN1-mediated ubiquitination and degradation prevents adipocyte differentiation. Cell Death Differ 2013; 21:594-603. [PMID: 24336050 DOI: 10.1038/cdd.2013.181] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 11/05/2013] [Accepted: 11/11/2013] [Indexed: 11/08/2022] Open
Abstract
The central regulator of adipogenesis, PPARγ, is a nuclear receptor that is linked to obesity and metabolic diseases. Here we report that MKRN1 is an E3 ligase of PPARγ that induces its ubiquitination, followed by proteasome-dependent degradation. Furthermore, we identified two lysine sites at 184 and 185 that appear to be targeted for ubiquitination by MKRN1. Stable overexpression of MKRN1 reduced PPARγ protein levels and suppressed adipocyte differentiation in 3T3-L1 and C3H10T1/2 cells. In contrast, MKRN1 depletion stimulated adipocyte differentiation in these cells. Finally, MKRN1 knockout MEFs showed an increased capacity for adipocyte differentiation compared with wild-type MEFs, with a concomitant increase of PPARγ and adipogenic markers. Together, these data indicate that MKRN1 is an elusive PPARγ E3 ligase that targets PPARγ for proteasomal degradation by ubiquitin-dependent pathways, and further depict MKRN1 as a novel target for diseases involving PPARγ.
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175
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Choi SH, Silvey DT, Johnson BJ, Doumit ME, Chung KY, Sawyer JE, Go GW, Smith SB. Conjugated linoleic acid (t-10, c-12) reduces fatty acid synthesis de novo, but not expression of genes for lipid metabolism in bovine adipose tissue ex vivo. Lipids 2013; 49:15-24. [PMID: 24293227 DOI: 10.1007/s11745-013-3869-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/18/2013] [Indexed: 12/25/2022]
Abstract
We hypothesized that exogenous fatty acids, and especially or 18:2 trans-10, cis-12 conjugated linoleic acid (CLA), would decrease adipogenic and lipogenic gene expression and de novo fatty acid biosynthesis in intramuscular (i.m.) and subcutaneous (s.c.) adipose tissues. Fresh i.m. and s.c. adipose tissues were collected from the longissimus thoracis muscle of Angus steers at 12, 14, and 16 months of age (n = 4 per time point). Adipose tissue explants were incubated in duplicate for 48 h with 40 μM α-linolenic (ALA), oleic, stearic, trans-vaccenic, or CLA. Adipocyte size, acetate and glucose incorporation into fatty acids in vitro and mRNA levels for C/EBPβ, CPT1β, GPR43, PPARγ, PRKAA1 (AMPKα) and SCD1 were measured following the incubations. PRKAA1 and SCD1gene expression were greater (P < 0.001) in s.c. adipose tissue than in i.m. adipose tissue and acetate incorporation into lipids and C/EBPβ, PPARγ, and SCD1gene expression were greater at 16 months of age than at 12 months of age in i.m. adipose (P < 0.01). C/EBPβ gene expression increased by 16 months of age and PRKAA1 gene expression decreased by 16 months of age in s.c. adipose tissue. All fatty acids increased s.c. adipocyte volumes whereas CLA decreased acetate incorporation into lipids in s.c. adipose tissue (P < 0.05), but none of the fatty acids affected gene expression in i.m. or s.c. adipose tissue (P > 0.10). Thus, CLA depressed de novo fatty acid biosynthesis from acetate but neither CLA nor other fatty acids significantly affected adipogenic or lipogenic gene expression.
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Affiliation(s)
- Seong Ho Choi
- Department of Animal Science, Chungbuk National University, Chungbuk, 361-763, Korea
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176
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Shimada Y, Kuroyanagi J, Zhang B, Ariyoshi M, Umemoto N, Nishimura Y, Tanaka T. Downregulation of Max dimerization protein 3 is involved in decreased visceral adipose tissue by inhibiting adipocyte differentiation in zebrafish and mice. Int J Obes (Lond) 2013; 38:1053-60. [PMID: 24254064 DOI: 10.1038/ijo.2013.217] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/16/2013] [Accepted: 11/05/2013] [Indexed: 01/14/2023]
Abstract
BACKGROUND The diet-induced obesity model of zebrafish (DIO-zebrafish) share a common pathophysiological pathway with mammalian obesity. OBJECTIVES We aimed to investigate the role of Max dimerization protein 3 (MXD3) in visceral fat accumulation and adipocyte differentiation, by conducting knockdown experiments using zebrafish and mouse preadipocytes. METHODS To identify genes related to visceral adiposity, we conducted transcriptome analyses of human and zebrafish obese populations using the Gene Expression Omnibus and DNA microarray. We then intraperitoneally injected morpholino antisense oligonucleotides (MO-mxd3) to knockdown mxd3 gene expression in DIO-zebrafish and measured several parameters, which reflected human obesity and associated metabolic diseases. Finally, lentiviral Mxd3 shRNA knockdown in mouse 3T3-L1 preadipocytes was conducted. Quantitative PCR analyses of several differentiation markers were conducted during these gene knockdown experiments. RESULTS We found that MXD3 expression was increased in the obese population in humans and zebrafish. Intraperitoneal MO-mxd3 administration to DIO-zebrafish suppressed the increase in body weight, visceral fat accumulation and the size of mature adipocytes. Subsequently, dyslipidemia and liver steatosis were also ameliorated by MO-mxd3. In mouse adipocytes, Mxd3 expression was drastically increased in the early differentiation stage. Mxd3 shRNA inhibited preadipocyte proliferation and adipocyte maturation. Quantitative PCR analyses showed that the early differentiation marker, CCAAT/enhancer-binding protein delta (Cebpd) and late differentiation markers (CCAAT/enhancer-binding protein, alpha and peroxisome proliferator-activated receptor gamma) were downregulated by Mxd3 knockdown in 3T3-L1 cells and DIO-zebrafish. Subsequently, mature adipocyte markers (adiponectin and caveolin 1 for zebrafish, and fatty acid binding protein 4 and stearoyl-coenzyme A desaturase 1 for mouse adipocytes) were also decreased. CONCLUSION Mxd3 regulates preadipocyte proliferation and early adipocyte differentiation via Cebpd downregulation in vitro and in vivo. Integrated analysis of human and zebrafish transcriptomes allows identification of a novel therapeutic target against human obesity and further associated metabolic disease.
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Affiliation(s)
- Y Shimada
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan [3] Mie University Medical Zebrafish Research Center, Mie, Japan [4] Department of Bioinformatics, Mie University Life Science Research Center, Mie, Japan [5] Department of Omics Medicine, Mie University Industrial Technology Innovation, Mie, Japan
| | - J Kuroyanagi
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan
| | - B Zhang
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan
| | - M Ariyoshi
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan
| | - N Umemoto
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan
| | - Y Nishimura
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan [3] Mie University Medical Zebrafish Research Center, Mie, Japan [4] Department of Bioinformatics, Mie University Life Science Research Center, Mie, Japan [5] Department of Omics Medicine, Mie University Industrial Technology Innovation, Mie, Japan
| | - T Tanaka
- 1] Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan [2] Department of Systems Pharmacology, Mie University Graduate School of Medicine, Mie, Japan [3] Mie University Medical Zebrafish Research Center, Mie, Japan [4] Department of Bioinformatics, Mie University Life Science Research Center, Mie, Japan [5] Department of Omics Medicine, Mie University Industrial Technology Innovation, Mie, Japan
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177
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Sequence analysis of bovine C/EBPδ gene and its adipogenic effects on fibroblasts. Mol Biol Rep 2013; 41:251-7. [PMID: 24213926 DOI: 10.1007/s11033-013-2858-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 10/31/2013] [Indexed: 01/01/2023]
Abstract
CCAAT/enhancer binding protein delta (C/EBPδ), an important transcriptional factor, regulates cell growth, differentiation and adipogenesis in humans and mice. However, we lack of directive information on the effects of C/EBPδ gene in bovine cells. In the present study, we cloned the CDS areas of bovine C/EBPδ gene and predicted its sequence characteristics. Moreover, we constructed the recombinant adenovirus plasmids of bovine C/EBPδ gene and harvested the subsequent adenoviruses to infect bovine primary fibroblasts. Oil Red O staining results showed lipid droplets accumulated gradually in the adenoviruses treated fibroblasts. Time course real-time PCR results indicated that over-expression of exogenous C/EBPδ regulated the mRNA expression levels of some key adipogenic genes, herein, activated the C/EBPα expression, increased lipoprotein lipase and fatty acid binding protein 4 mRNA expression levels, whereas inhibited leptin receptor gene. In conclusion, the present study demonstrates that the elevated C/EBPδ can induce the adipogenesis in the fibroblasts of cattle.
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178
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Abstract
NASH is a common liver disease that increases liver-related mortality and reduces survival. The need for optimal management of NASH is therefore a priority for today's practicing hepatologist. The rationale for specific pharmacological therapy for NASH is based on the potential for disease progression and the difficulties that many patients have successfully implementing, in the long term, diet and lifestyle changes. Even in those that succeed, limited evidence exists that severe liver injury in patients with NASH can be reversed by diet and lifestyle measures alone. This Review provides a personal and critical assessment of the histological efficacy and safety of agents tested in randomized trials in patients with NASH.
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Affiliation(s)
- Vlad Ratziu
- Department of Hepatology and Gastroenterology, Hôpital Pitié Salpêtrière, 47-83 Boulevard de l'Hôpital, CdR Saint-Antoine, Paris 75651, France.
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179
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Nguyen MT, Csermely P, Sőti C. Hsp90 chaperones PPARγ and regulates differentiation and survival of 3T3-L1 adipocytes. Cell Death Differ 2013; 20:1654-63. [PMID: 24096869 DOI: 10.1038/cdd.2013.129] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 07/24/2013] [Accepted: 08/21/2013] [Indexed: 11/09/2022] Open
Abstract
Adipose tissue dysregulation has a major role in various human diseases. The peroxisome proliferator-activated receptor-γ (PPARγ) is a key regulator of adipocyte differentiation and function, as well as a target of insulin-sensitizing drugs. The Hsp90 chaperone stabilizes a diverse set of signaling 'client' proteins, thereby regulates various biological processes. Here we report a novel role for Hsp90 in controlling PPARγ stability and cellular differentiation. Specifically, we show that the Hsp90 inhibitors geldanamycin and novobiocin efficiently impede the differentiation of murine 3T3-L1 preadipocytes. Geldanamycin at higher concentrations also inhibits the survival of both developing and mature adipocytes, respectively. Further, Hsp90 inhibition disrupts an Hsp90-PPARγ complex, leads to the destabilization and proteasomal degradation of PPARγ, and inhibits the expression of PPARγ target genes, identifying PPARγ as an Hsp90 client. A similar destabilization of PPARγ and a halt of adipogenesis also occur in response to protein denaturing stresses caused by a single transient heat-shock or proteasome inhibition. Recovery from stress restores PPARγ stability and adipocyte differentiation. Thus, our findings reveal Hsp90 as a critical stress-responsive regulator of adipocyte biology and offer a potential therapeutic target in obesity and the metabolic syndrome.
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Affiliation(s)
- M T Nguyen
- Department of Medical Chemistry, Semmelweis University, Budapest, Hungary
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180
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Arsenijevic T, Gregoire F, Chiadak J, Courtequisse E, Bolaky N, Perret J, Delporte C. Pituitary adenylate cyclase activating peptide (PACAP) participates in adipogenesis by activating ERK signaling pathway. PLoS One 2013; 8:e72607. [PMID: 24039785 PMCID: PMC3767812 DOI: 10.1371/journal.pone.0072607] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 07/12/2013] [Indexed: 11/19/2022] Open
Abstract
Pituitary adenylate cyclase activating peptide (PACAP) belongs to the secretin/glucagon/vasoactive intestinal peptide (VIP) family. Its action can be mediated by three different receptor subtypes: PAC1, which has exclusive affinity for PACAP, and VPAC1 and VPAC2 which have equal affinity for PACAP and VIP. We showed that all three receptors are expressed in 3T3-L1 cells throughout their differentiation into adipocytes. We established the activity of these receptors by cAMP accumulation upon induction by PACAP. Together with insulin and dexamethasone, PACAP induced adipogenesis in 3T3-L1 cell line. PACAP increased cAMP production within 15 min upon stimulation and targeted the expression and phosphorylation of MAPK (ERK1/2), strengthened by the ERK1/2 phosphorylation being partially or completely abolished by different combinations of PACAP receptors antagonists. We therefore speculate that ERK1/2 activation is crucial for the activation of CCAAT/enhancer- binding protein β (C/EBPβ).
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Affiliation(s)
- Tatjana Arsenijevic
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Françoise Gregoire
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Jeanne Chiadak
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Elodie Courtequisse
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Nargis Bolaky
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Jason Perret
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
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181
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Gathercole LL, Lavery GG, Morgan SA, Cooper MS, Sinclair AJ, Tomlinson JW, Stewart PM. 11β-Hydroxysteroid dehydrogenase 1: translational and therapeutic aspects. Endocr Rev 2013; 34:525-55. [PMID: 23612224 DOI: 10.1210/er.2012-1050] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts the inactive glucocorticoid cortisone and its active form cortisol. It is widely expressed and, although bidirectional, in vivo it functions predominantly as an oxoreductase, generating active glucocorticoid. This allows glucocorticoid receptor activation to be regulated at a prereceptor level in a tissue-specific manner. In this review, we will discuss the enzymology and molecular biology of 11β-HSD1 and the molecular basis of cortisone reductase deficiencies. We will also address how altered 11β-HSD1 activity has been implicated in a number of disease states, and we will explore its role in the physiology and pathologies of different tissues. Finally, we will address the current status of selective 11β-HSD1 inhibitors that are in development and being tested in phase II trials for patients with the metabolic syndrome. Although the data are preliminary, therapeutic inhibition of 11β-HSD1 is also an exciting prospect for the treatment of a variety of other disorders such as osteoporosis, glaucoma, intracranial hypertension, and cognitive decline.
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Affiliation(s)
- Laura L Gathercole
- School of Clinical and Experimental Medicine, University of Birmingham, Queen Elizabeth Hospital, Edgbaston B15 2TH, United Kingdom
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182
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Ren J, Li D, Li Y, Lan X, Zheng J, Wang X, Ma J, Lu S. HDAC3 interacts with sumoylated C/EBPα to negatively regulate the LXRα expression in rat hepatocytes. Mol Cell Endocrinol 2013; 374:35-45. [PMID: 23639777 DOI: 10.1016/j.mce.2013.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 04/16/2013] [Accepted: 04/19/2013] [Indexed: 01/22/2023]
Abstract
The expression changes of liver X receptor alpha (LXRα), histone deacetylase 3 (HDAC3) and CCAAT/enhancer binding protein alpha (C/EBPα) were detected in liver tissues of our high-fat-diet E3 rat model. The aim of this study is to pinpoint the molecular mechanism of HDAC3 and C/EBPα to orchestrate LXRα expression in hepatocytes. We confirmed that LXRα and its target genes were negatively regulated by HDAC3 in stable expressed clones with pEGFP-Hdac3 or shRNA-Hdac3 vector. However, transient pEGFP-C/EBPα plasmid transfection showed an upregulation of LXRα expression and C/EBPα enhanced LXRα promoter activity in a dose-dependent manner in CBRH-7919 cells. By using 5'-serial deletion reporter analysis, we identified that fragment from -2881 to -1181bp of LXRα promoter was responsible for C/EBPα binding to the promoter, especially CBS1 and CBS4 were identified essentially by using ChIP and luciferase reporter assay. Co-IP, qRT-PCR and ChIP revealed that HDAC3 interacted with C/EBPα co-regulated LXRα expression. Sumoylation of C/EBPα at lysine 159 was detected in CBRH-7919 cells with transient overexpressed C/EBPα, and Co-IP assay detected that sumoylated C/EBPα interacted with more HDAC3 than C/EBPα K159L mutant. Luciferase reporter assay demonstrated that C/EBPα participated in HDAC3-repressed LXRα transcription, and HDAC3 was involved in sumoylated C/EBPα-inactivated LXRα activity. Luciferase reporter assay demonstrated that sumoylation of C/EBPα by SUMO-1 directly reversed the activation of C/EBPα on LXRα promoter. The results suggested that HDAC3 interacts with sumoylated C/EBPα to negatively regulate the LXRα expression.
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Affiliation(s)
- Juan Ren
- Department of Genetics and Molecular Biology, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710061, PR China
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183
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Tan JTM, McLennan SV, Williams PF, Rezaeizadeh A, Lo LWY, Bonner JG, Twigg SM. Connective tissue growth factor/CCN-2 is upregulated in epididymal and subcutaneous fat depots in a dietary-induced obesity model. Am J Physiol Endocrinol Metab 2013; 304:E1291-302. [PMID: 23571711 DOI: 10.1152/ajpendo.00654.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Connective tissue growth factor (CTGF), also known as CCN-2, is a cysteine-rich secreted protein that is involved in a range of biological processes, including regulation of cell growth and differentiation. Our previous in vitro studies have shown that CCN-2 inhibits adipocyte differentiation, although whether CCN-2 is regulated in vivo in adipogenesis is undetermined and was investigated in this study. C57BL/6 male mice were fed either standard laboratory chow (ND) or a diet high in fat (HFD; 45% fat) for 15 or 24 wk. HFD animals that gained >5 g in weight (termed HFD-fat) were insulin resistant and were compared with HFD-fed animals, which failed to gain weight (termed HFD-lean). HFD-fat mice had significantly increased CCN-2 mRNA levels in both the subcutaneous and epididymal fat pads, whereas CCN-2 mRNA was not induced in the epididymal site in HFD-lean mice. Also in HFD-fed animals, epididymal CCN-2 mRNA correlated positively with key genes involved in adipocyte differentiation, adiponectin and PPARγ (P < 0.001 and P < 0.002, respectively). Additionally, epididymal CCN-2 mRNA correlated positively with two markers of tissue turnover, PAI-1 in HFD-fat mice only and TIMP-1, but only in the HFD-lean mice. Collectively, these findings suggest that CCN-2 plays a role in adipocyte differentiation in vivo and thus in the pathogenesis of obesity linked with insulin resistance.
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Affiliation(s)
- Joanne T M Tan
- Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia; and
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184
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Jeong JY, Kim JS, Nguyen TH, Lee HJ, Baik M. Wnt/β-catenin signaling and adipogenic genes are associated with intramuscular fat content in the longissimus dorsi muscle of Korean cattle. Anim Genet 2013; 44:627-35. [PMID: 23742632 DOI: 10.1111/age.12061] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2013] [Indexed: 12/18/2022]
Abstract
Intramuscular fat (IMF) is an important trait that influences beef quality. In two studies, we examined the possible involvement of the Wnt/β-catenin signaling pathway in IMF deposition in Korean cattle. In study 1, using a group of bulls and steers, we found that castration, a non-genetic factor, decreased (P < 0.01) the expression of both the WNT10B and CTNNB1 genes, whereas it increased the expression of the Wnt antagonist secreted frizzled-related proteins 4 (SFRP4, P < 0.001) and the adipogenic CCAAT/enhancer binding protein (C/EPB), alpha (CEBPA, P < 0.001) and peroxisome proliferator-activated receptor gamma (PPARG, P < 0.05) genes in longissimus dorsi muscle (LM) tissue. The WNT10B and CTNNB1 mRNA levels showed strong (P < 0.001) negative correlations (r = -0.68 and r = -0.73 respectively) with the IMF content, whereas the SFRP4, CEBPA and PPARG mRNA levels showed strong (P < 0.01) positive correlations (r = 0.70, 0.70 and 0.64 respectively) with the IMF content. Large variation still exists in the IMF content of steers, implying that genetic factors affect IMF deposition. Using a different group of steers, a correlation analysis in study 2 also showed that the expression of the WNT10B and CTNNB1 genes, and SFRP4 and adipogenic genes was negatively and positively associated with the IMF content respectively. Our findings suggest that downregulation of the Wnt/β-catenin signaling pathway genes, but upregulation of Wnt antagonist SFRP4 and adipogenic gene expression following castration, contributes to increased IMF deposition in the LM. Our results demonstrate that both non-genetic factors (castration) and genetic variation within the steer group affect the gene expression pattern of the Wnt/β-catenin signaling pathway.
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Affiliation(s)
- J Y Jeong
- Division of Animal Genomics and Bioinformatics, National Institute of Animal science, Rural Development Administration, #564 Omockchun-dong, Suwon, 441-706, Republic of Korea
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185
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Seo SG, Yang H, Shin SH, Min S, Kim YA, Yu JG, Lee DE, Chung MY, Heo YS, Kwon JY, Yue S, Kim KH, Cheng JX, Lee KW, Lee HJ. A metabolite of daidzein, 6,7,4'-trihydroxyisoflavone, suppresses adipogenesis in 3T3-L1 preadipocytes via ATP-competitive inhibition of PI3K. Mol Nutr Food Res 2013; 57:1446-55. [PMID: 23737351 DOI: 10.1002/mnfr.201200593] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 02/16/2013] [Accepted: 02/19/2013] [Indexed: 01/07/2023]
Abstract
SCOPE Daidzein is one of the major soy isoflavones. Following ingestion, daidzein is readily metabolized in the liver and converted into hydroxylated metabolites. One such metabolite is 6,7,4'-trihydroxyisoflavone (6,7,4'-THIF), which has been the focus of recent studies due to its various health benefits, however, its anti-adipogenic activity has not been investigated. Our objective was to determine the effects of 6,7,4'-THIF on adipogenesis in 3T3-L1 preadipocytes and elucidate the mechanisms of action involved. METHODS AND RESULTS Adipogenesis was stimulated in 3T3-L1 preadipocytes. Both 6,7,4'-THIF and daidzein were treated in the presence and absence of mixture of isobutylmethylxanthine, dexamethasone, and insulin (MDI). We observed that 6,7,4'-THIF, but not daidzein, inhibited MDI-induced adipogenesis significantly at 40 and 80 μM, associated with decreased peroxisome proliferator-activated receptor-γ and C/EBP-α protein expression. 6,7,4'-THIF significantly suppressed MDI-induced lipid accumulation in the early stage of adipogenesis, attributable to a suppression of cell proliferation and the induction of cell cycle arrest. We also determined that 6,7,4'-THIF, but not daidzein, attenuated phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. 6,7,4'-THIF was found to inhibit PI3K activity via direct binding in an ATP-competitive manner. CONCLUSION Our results suggest that 6,7,4'-THIF suppresses adipogenesis in 3T3-L1 preadipocytes by directly targeting PI3K. Soy isoflavones like 6,7,4'-THIF may have potential for development into novel treatment strategies for chronic obesity.
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Affiliation(s)
- Sang Gwon Seo
- WCU Biomodulation Major, Center for Food and Bioconvergence, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
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186
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Gaya M, Repetto V, Toneatto J, Anesini C, Piwien-Pilipuk G, Moreno S. Antiadipogenic effect of carnosic acid, a natural compound present in Rosmarinus officinalis, is exerted through the C/EBPs and PPARγ pathways at the onset of the differentiation program. Biochim Biophys Acta Gen Subj 2013; 1830:3796-806. [DOI: 10.1016/j.bbagen.2013.03.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 02/21/2013] [Accepted: 03/20/2013] [Indexed: 01/24/2023]
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187
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Honda T, Ishii A, Inui M. Regulation of adipocyte differentiation of 3T3-L1 cells by PDZRN3. Am J Physiol Cell Physiol 2013; 304:C1091-7. [DOI: 10.1152/ajpcell.00343.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PDZRN3, a member of the PDZRN (or LNX) family of proteins, is essential for the differentiation of mesenchymal stem cells into myotubes, but it plays an inhibitory role in the differentiation of these cells into osteoblasts. Given that mesenchymal stem cells also differentiate into adipocytes, we examined the possible role of PDZRN3 in adipogenesis in mouse 3T3-L1 preadipocytes. The expression of PDZRN3 decreased at both the mRNA and protein levels during adipogenic differentiation. RNAi-mediated depletion of PDZRN3 enhanced the differentiation of 3T3-L1 cells into adipocytes as assessed on the basis of lipid accumulation. The upregulation of aP2 and CCAAT/enhancer-binding protein (C/EBP)-β during adipocyte differentiation was also enhanced in the PDZRN3-depleted cells, as was the induction of peroxisome proliferator-activated receptor-γ (PPARγ), an upstream regulator of aP2 and C/EBPα, at both the mRNA and protein levels. Among transcription factors that control the expression of PPARγ, we found that STAT5b, but not STAT5a, was upregulated in PDZRN3-depleted cells at both mRNA and protein levels. Tyrosine phosphorylation of STAT5b, but not that of STAT5a, was also enhanced at an early stage of differentiation by PDZRN3 depletion. In addition, the expression of C/EBPβ during the induction of differentiation was enhanced at the mRNA and protein levels in PDZRN3-depleted cells. Our results thus suggest that PDZRN3 negatively regulates adipogenesis in 3T3-L1 cells through downregulation of STAT5b and C/EBPβ and consequent suppression of PPARγ expression.
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Affiliation(s)
- Takeshi Honda
- Department of Pharmacology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Aiko Ishii
- Department of Pharmacology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Makoto Inui
- Department of Pharmacology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
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188
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Kim CY, Kim KH. Dexamethasone-induced selenoprotein S degradation is required for adipogenesis. J Lipid Res 2013; 54:2069-2082. [PMID: 23687306 DOI: 10.1194/jlr.m034603] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Although adipogenesis is associated with induction of endoplasmic reticulum (ER) stress, the role of selenoprotein S (SEPS1), an ER resident selenoprotein known to regulate ER stress and ER-associated protein degradation, is unknown. We found an inverse relationship between SEPS1 level in adipose tissue and adiposity in mice. While SEPS1 expression was increased during adipogenesis, a markedly reduced SEPS1 protein level was found in the early phase of adipogenesis due to dexamethasone (DEX)-induced proteosomal degradation of SEPS1. Overexpression of SEPS1 in the early phase of cell differentiation resulted in impairment of adipogenesis with reduced levels of CCAAT/enhancer binding protein α and other adipocyte marker genes during the course of adipogenesis. Conversely, knockdown of SEPS1 resulted in the promotion of adipogenesis. Additionally, altered SEPS1 expression was associated with changes in expression of ER stress marker genes in the early phase of adipogenesis, and ubiquitin-proteasome system (UPS)-related ubiquitination and proteasome function. Our study reveals that SEPS1 is a novel anti-adipogenic selenoprotein that modulates ER stress- and UPS-dependent adipogenesis. Our results also identifies a novel function of DEX in the regulation of adipogenesis through induction of SEPS1 degradation. Taken together, DEX-dependent degradation of SEPS1 in the early phase of adipogenesis is necessary for initiating ER stress- and UPS-dependent maturation of adipocytes.
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Affiliation(s)
- Choon Young Kim
- Department of Food Science, Purdue University, West Lafayette, IN 47907
| | - Kee-Hong Kim
- Department of Food Science, Purdue University, West Lafayette, IN 47907.
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189
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Abdou HS, Atlas E, Haché RJG. A positive regulatory domain in CCAAT/enhancer binding protein β (C/EBPΒ) is required for the glucocorticoid-mediated displacement of histone deacetylase 1 (HDAC1) from the C/ebpα promoter and maximum adipogenesis. Endocrinology 2013; 154:1454-64. [PMID: 23456364 DOI: 10.1210/en.2012-2061] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glucocorticoids promote adipogenesis and contribute to the metabolic syndrome through a number of mechanisms. One of the effectors of glucocorticoid action is the CCAAT/enhancer binding protein β (C/EBPβ). C/EBPβ is a basic leucine-zipper transcription factor involved in diverse processes including differentiation, cellular proliferation, and inflammation. C/EBPβ transcriptional activity is regulated, in part, by its acetylation profile resulting from its dynamic interaction with either acetylases general control nonrepressed protein 5/p300/CBP associated factor (GCN5/PCAF) or deacetylase complexes (mSin3A/histone deacetylase 1 [HDAC1]). Glucocorticoid treatment of preadipocytes promotes C/EBPβ acetylation, leading to mSin3A/HDAC1 dissociation from C/EBPβ and resulting in C/ebpα promoter activation at the onset of adipogenesis, thus increasing the differentiation rate. We recently showed that the regulatory domain 1 (RD1) of C/EBPβ contains four residues (153-156) required for its interaction with HDAC1, therefore supporting RD1 proposed inhibitory role. In an attempt to further elucidate the intrinsic regulatory property of RD1, we sought to characterize the regulatory potential of the N terminus region of RD1 (residues 141-149). In this study, we show that C/EBPβΔ141-149 transcriptional activity was compromised on the C/ebpα, but not on the Pparγ, promoter. Additionally, the ability of C/EBPβΔ141-149 to induce adipogenesis in NIH 3T3 cells was compromised when compared with C/EBPβwt owing to a delayed expression of C/ebpα at the onset of differentiation. Furthermore, the data suggest that the reduced expression of C/ebpα in cells expressing C/EBPβΔ141-149 was due to a persistent recruitment of HDAC1 to the C/ebpα promoter after glucocorticoid treatment. Together, these results suggest that amino acids 141-149 of C/EBPβ act as a positive regulatory domain required for maximum transcriptional activity.
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Affiliation(s)
- Houssein-Salem Abdou
- Reproduction, Mother and Youth Health, CHUQ Research Centre, Quebec City, Quebec, Canada
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190
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Wei Z, Seldin MM, Natarajan N, Djemal DC, Peterson JM, Wong GW. C1q/tumor necrosis factor-related protein 11 (CTRP11), a novel adipose stroma-derived regulator of adipogenesis. J Biol Chem 2013; 288:10214-29. [PMID: 23449976 DOI: 10.1074/jbc.m113.458711] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
C1q/TNF-related proteins (CTRPs) are a family of secreted regulators of glucose and lipid metabolism. Here, we describe CTRP11, a novel and phylogenetically conserved member of the C1q family. Our studies revealed that white and brown adipose are major tissues that express CTRP11, and its expression is acutely regulated by changes in metabolic state. Within white adipose tissue, CTRP11 is primarily expressed by stromal vascular cells. As a secreted multimeric protein, CTRP11 forms disulfide-linked oligomers. Although the conserved N-terminal Cys-28 and Cys-32 are dispensable for the assembly of higher-order oligomeric structures, they are unexpectedly involved in modulating protein secretion. When co-expressed, CTRP11 forms heteromeric complexes with closely related CTRP10, CTRP13, and CRF (CTRP14) via the C-terminal globular domains, combinatorial associations that potentially generate functionally distinct complexes. Functional studies revealed a role for CTRP11 in regulating adipogenesis. Ectopic expression of CTRP11 or exposure to recombinant protein inhibited differentiation of 3T3-L1 adipocytes. The expression of peroxisome proliferator-activated receptor-γ and CAAT/enhancer binding protein-α, which drive the adipogenic gene program, was markedly suppressed by CTRP11. Impaired adipogenesis was caused by a CTRP11-mediated decrease in p42/44-MAPK signaling and inhibition of mitotic clonal expansion, a process essential for adipocyte differentiation in culture. These results implicate CTRP11 as a novel secreted regulator of adipogenesis and highlight the potential paracrine cross-talk between adipocytes and cells of the stromal vascular compartment in maintaining adipose tissue homeostasis.
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Affiliation(s)
- Zhikui Wei
- Department of Physiology and Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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191
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Yang JY, Cho SW, An JH, Jung JY, Kim SW, Kim SY, Kim JE, Shin CS. Osteoblast-targeted overexpression of TAZ increases bone mass in vivo. PLoS One 2013; 8:e56585. [PMID: 23441207 PMCID: PMC3575506 DOI: 10.1371/journal.pone.0056585] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 01/11/2013] [Indexed: 01/28/2023] Open
Abstract
Osteoblasts are derived from mesenchymal progenitors. Differentiation to osteoblasts and adipocytes is reciprocally regulated. Transcriptional coactivator with a PDZ-binding motif (TAZ) is a transcriptional coactivator that induces differentiation of mesenchymal cells into osteoblasts while blocking differentiation into adipocytes. To investigate the role of TAZ on bone metabolism in vivo, we generated transgenic mice that overexpress TAZ under the control of the procollagen type 1 promoter (Col1-TAZ). Whole body bone mineral density (BMD) of 6- to 19-week-old Col-TAZ mice was 4% to 7% higher than that of their wild-type (WT) littermates, whereas no difference was noticed in Col.1-TAZ female mice. Microcomputed tomography analyses of proximal tibiae at 16 weeks of age demonstrated a significant increase in trabecular bone volume (26.7%) and trabecular number (26.6%) with a reciprocal decrease in trabecular spacing (14.2%) in Col1-TAZ mice compared with their WT littermates. In addition, dynamic histomorphometric analysis of the lumbar spine revealed increased mineral apposition rate (42.8%) and the serum P1NP level was also significantly increased (53%) in Col.1-TAZ mice. When primary calvaria cells were cultured in osteogenic medium, alkaline phosphatase (ALP) activity was significantly increased and adipogenesis was significantly suppressed in Col1-TAZ mice compared with their WT littermates. Quantitative real-time polymerase chain reaction analyses showed that expression of collagen type 1, bone sialoprotein, osteocalcin, ALP, osterix, and Runx2 was significantly increased in calvaria cells from Col1-TAZ mice compared to their WT littermates. In vitro, TAZ enhanced Runx2-mediated transcriptional activity while suppressing the peroxisome proliferator-activated receptor gamma signaling pathway. TAZ also enhanced transcriptional activity from 3TP-Lux, which reflects transforming growth factor-beta (TGF-β)-mediated signaling. In addition, TAZ enhanced TGF-β-dependent nuclear translocation of Smad2/3 and Smad4. Taken together, these results suggest that TAZ positively regulates bone formation in vivo, which seems to be mediated by enhancing both Runx2 and TGF-β signaling.
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Affiliation(s)
- Jae-Yeon Yang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sun Wook Cho
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jee Hyun An
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Ju Yeon Jung
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sang Wan Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Seong Yeon Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jung Eun Kim
- Department of Molecular Medicine, Kyungpook National University School of Medicine, Daegu, Korea
| | - Chan Soo Shin
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
- * E-mail:
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192
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Lee HL, Woo KM, Ryoo HM, Baek JH. Distal-less homeobox 5 inhibits adipogenic differentiation through the down-regulation of peroxisome proliferator-activated receptor γ expression. J Cell Physiol 2012; 228:87-98. [PMID: 22553076 DOI: 10.1002/jcp.24106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Distal-less homeobox 5 (Dlx5) is a positive regulator of osteoblast differentiation that contains a homeobox domain. Because there are possible reciprocal relationships between osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells (MSCs), we examined the regulatory role of Dlx5 in adipogenic differentiation in this study. Adipogenic stimuli suppressed the expression levels of Dlx5 mRNA in mouse bone marrow stromal cells. Over-expression of Dlx5 inhibited adipogenic differentiation in human bone marrow MSCs and 3T3-L1 preadipocytic cells whereas knockdown of Dlx5 enhanced adipogenic differentiation in 3T3-L1 cells. Over-expression of Dlx5 suppressed the expression of adipogenic marker genes, including CCAAT/enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ). Dlx5-mediated suppression of adipogenic differentiation was overcome by over-expression of PPARγ but not by that of cAMP response element binding protein (CREB) or C/EBPα. Dlx5 decreased the transcriptional activity of CREB and C/EBPα in a dose-dependent manner. Dlx5 directly bound to CREB and C/EBPα and prevented them from binding to and subsequently transactivating the PPARγ promoter. These results suggest that Dlx5 plays an important regulatory role in fate determination of bone marrow MSCs toward the osteoblast lineage through the inhibition of adipocyte differentiation as well as the direct stimulation of osteoblast differentiation.
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Affiliation(s)
- Hye-Lim Lee
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749, Korea
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193
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Wu Z, Wang S. Role of kruppel-like transcription factors in adipogenesis. Dev Biol 2012; 373:235-43. [PMID: 23142072 DOI: 10.1016/j.ydbio.2012.10.031] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 10/31/2012] [Accepted: 10/31/2012] [Indexed: 01/27/2023]
Abstract
The zinc-finger transcription factors of the kruppel-like factor family (KLF) are critical in many physiological and pathological processes including cell proliferation, differentiation, inflammation, and apoptosis. Recently, there is increasing evidence that suggests these KLFs have an important role in fat biology. This review summarizes the role of KLFs in lipid metabolism, especially in adipogenesis, and reveals the relationship networks among members of KLF family in differentiation.
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Affiliation(s)
- Zeni Wu
- School of Public Health, Wuhan University, Wuhan, China
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194
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Park BO, Ahrends R, Teruel MN. Consecutive positive feedback loops create a bistable switch that controls preadipocyte-to-adipocyte conversion. Cell Rep 2012; 2:976-90. [PMID: 23063366 PMCID: PMC4959269 DOI: 10.1016/j.celrep.2012.08.038] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/10/2012] [Accepted: 08/31/2012] [Indexed: 12/12/2022] Open
Abstract
Adipogenesis, or the conversion of proliferating preadipocytes into nondividing adipocytes, is an important part of the vertebrate weight-maintenance program. It is not yet understood how and when an irreversible transition occurs into a distinct state capable of accumulating lipid. Here, we use single-cell fluorescence imaging to show that an all-or-none switch is induced before lipid accumulation occurs. Conversion begins by glucocorticoid and cAMP signals raising C/EBPβ levels above a critical threshold, triggering three consecutive positive feedback loops: from PPARγ to C/EBPα, then to C/EBPβ, and last to the insulin receptor. Experiments and modeling show that these feedbacks create a robust, irreversible transition to a terminally differentiated state by rejecting short- and low-amplitude stimuli. After the differentiation switch is triggered, insulin controls fat accumulation in a graded fashion. Altogether, our study introduces a regulatory motif that locks cells in a differentiated state by engaging a sequence of positive feedback loops.
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Affiliation(s)
- Byung Ouk Park
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Robert Ahrends
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Mary N. Teruel
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
- Correspondence:
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195
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Abstract
Autografting of lost soft tissue is an important subject of the plastic and reconstructive surgery and autograft of fat pads has been only technique for this goal. However, the results are disappointing because of absorption of the grafts with time. Adipoblasts or adipocyte precursor cells distribute widely in connective tissues and they can proliferate and mature into adipocytes even in the adult body. In experiments using mice, we found that de novo adipogenesis of endogenous precursor cells can be induced by injecting reconstituted basement membrane, Matrigel, supplemented with more than 1 ng/ml of bFGF. This adipogenesis was reproducibly induced by subcutaneous injection over the chest, lateral abdomen or head. Adipogenesis was induced even in ear cartilage or in muscle. To evaluate the possibility of future application of this de novo adipogenesis to plastic and reconstructive surgery, we have reviewed updated knowledge of the adipogenesis.
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196
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Regulation of lipid accumulation in 3T3-L1 cells: insulin-independent and combined effects of fatty acids and insulin. Animal 2012; 2:92-9. [PMID: 22444967 DOI: 10.1017/s1751731107000936] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The insulin-independent and combined effects of fatty acids (FA; linoleic and oleic acids) and insulin in modulating lipid accumulation and adipogenesis in 3T3-L1 cells was investigated using a novel protocol avoiding the effects of a complex hormone 'induction' mixture. 3T3-L1 cells were cultured in Dulbecco's modified Eagle's medium (DMEM) plus serum (control) or in DMEM plus either 0.3 mmol/l linoleic or oleic acids with 0.3 mmol/l FA-free bovine serum albumin in the presence or absence of insulin. Cells were cultured for 4 to 8 days and cell number, lipid accumulation, peroxisome proliferator-activated receptor-gamma (PPAR-γ) and glucose transporter 4 (GLUT-4) protein expression were determined. Cell number appeared to be decreased in comparison with control cultures. In both oleic acid and linoleic acid-treated cells, notably in the absence (and presence) of insulin, oil-red O stain-positive cells showed abundant lipid. The percentage of cells showing lipid accumulation was greater in FA-treated cultures compared with control cells grown in DMEM plus serum (P < 0.001). Treatment with both linoleic and oleic acid-containing media evoked higher levels of PPAR-γ than observed in control cultures (P < 0.05). GLUT-4 protein also increased in response to treatment with both linoleic and oleic acid-containing media (P < 0.001). Lipid accumulation in 3T3-L1 cells occurs in response to either oleic or linoleic acids independently of the presence of insulin. Both PPAR-γ and GLUT-4 protein expression were stimulated. Both proteins are considered markers of adipogenesis, and these observations suggest that these cells had entered the physiological state broadly accepted as differentiated. Furthermore, 3T3-L1 cells can be induced to accumulate lipid in a serum-free medium supplemented with FA, without the use of induction protocols using complex hormone mixtures. We have demonstrated a novel model for the study of lipid accumulation that will improve the understanding of adipogenesis in adipocyte lineage cells.
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197
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Abstract
Adipose tissue is an important site for lipid storage, energy homeostasis, and whole-body insulin sensitivity. It is important to understand the mechanisms involved in adipose tissue development and function, which can be regulated by the endocrine actions of various peptide and steroid hormones. Recent studies have revealed that white and brown adipocytes can be derived from distinct precursor cells. This review will focus on transcriptional control of adipogenesis and its regulation by several endocrine hormones. The general functions and cellular origins of adipose tissue and how the modulation of adipocyte development pertains to metabolic disease states will also be considered.
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198
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Watanabe T, Ito Y, Sato A, Hosono T, Niimi S, Ariga T, Seki T. Annexin A3 as a negative regulator of adipocyte differentiation. J Biochem 2012; 152:355-63. [PMID: 22888117 DOI: 10.1093/jb/mvs084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Annexin A3 is a protein belonging to the annexin family, and it is mainly present in cellular membranes as a phospholipid-binding protein that binds via the calcium ion. However, its physiological function remains to be clarified. We examined the expression of annexin A3 in mouse tissues and found for the first time that annexin A3 mRNA and its protein were expressed more strongly in adipose tissues than in other tissues. In adipose tissues, annexin A3-expressing cells were present in the stromal vascular fraction, and precisely identical to Pref-1-positive preadipocytes, Pref-1 being an epidermal growth factor repeat-containing transmembrane protein that inhibits adipogenesis. In 3T3-L1 cells, used as a model of adipogenesis, annexin A3 was down-regulated at an early phase of adipocyte differentiation, and this pattern paralleled that of Pref-1. Suppression of annexin A3 in these cells with siRNA caused elevation of the PPARγ2 mRNA level and lipid droplet accumulation. In conclusion, our data suggest that annexin A3 is a negative regulator of adipocyte differentiation.
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Affiliation(s)
- Takenori Watanabe
- Department of Chemistry and Life Science, Nihon University College of Bioresource Sciences, Kanagawa 252-0880, Japan
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199
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Analysis of the transcriptome of differentiating and non-differentiating preadipocytes from rats and humans by next generation sequencing. Mol Cell Biochem 2012; 369:175-81. [DOI: 10.1007/s11010-012-1380-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 06/20/2012] [Indexed: 10/28/2022]
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200
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Park JS, Rhee SD, Jung WH, Kang NS, Kim HY, Kang SK, Ahn JH, Kim KY. Anti-diabetic and anti-adipogenic effects of a novel selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor in the diet-induced obese mice. Eur J Pharmacol 2012; 691:19-27. [PMID: 22760069 DOI: 10.1016/j.ejphar.2012.06.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/13/2012] [Accepted: 06/13/2012] [Indexed: 01/22/2023]
Abstract
Glucocorticoid excess (Cushing's syndrome) causes metabolic syndrome such as visceral obesity, insulin resistance, diabetes mellitus, dyslipidaemia and hypertension. The selective inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) have considerable potential for treating type 2 diabetes mellitus and metabolic syndrome. In the present study, we investigated the anti-diabetic and anti-adipogenic effects of 4-(2-(1,1-dioxido-6-(2,4,6-trichlorophenyl)-1,2,6-thiadiazinan-2-yl)acetamido)adamantane-1-carboxamide (KR-67183), a novel selective 11β-HSD1 inhibitor; we also investigated the underlying molecular mechanisms in the cortisone-induced 3T3-L1 adipogenesis model system and diet-induced obese (DIO) mice. KR-67183 concentration-dependently inhibited 11β-HSD1 activity in human and mouse 11β-HSD1 over-expressed cells and in the ex vivo assay of C57BL/6 mice. In the study with DIO mice, the administration of KR-67183 (20 and 50mg/kg/day, orally for 28 days) improved the glucose tolerance and insulin sensitivity with suppressed 11β-HSD1 activity in the liver and fat. However, KR-67183 showed no change in the adrenal gland weight/body weight ratio and plasma corticosterone concentration in DIO mice. Further, KR-67183 suppressed adipocyte differentiation on cortisone-induced adipogenesis in 3T3-L1 cells is associated with the suppression of the cortisone-induced mRNA levels of FABP4, PPARγ2 and GLUT4, and 11β-HSD1 activity. Taken together, it is suggested that a selective 11β-HSD1 inhibitor, KR-67183, may provide a new therapeutic window in the prevention and treatment without toxicity in type 2 diabetes with obesity.
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Affiliation(s)
- Ji Seon Park
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology, PO Box 107, Yuseong-gu, Daejeon 305-600, Republic of Korea
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