101
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Lecoutre S, Breton C. Maternal nutritional manipulations program adipose tissue dysfunction in offspring. Front Physiol 2015; 6:158. [PMID: 26029119 PMCID: PMC4429565 DOI: 10.3389/fphys.2015.00158] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/30/2015] [Indexed: 12/11/2022] Open
Abstract
Based on the concept of Developmental Origin of Health and Disease, both human and animal studies have demonstrated a close link between nutrient supply perturbations in the fetus or neonate (i.e., maternal undernutrition, obesity, gestational diabetes and/or rapid catch-up growth) and increased risk of adult-onset obesity. Indeed, the adipose tissue has been recognized as a key target of developmental programming in a sex-and depot-specific manner. Despite different developmental time windows, similar mechanisms of adipose tissue programming have been described in rodents and in bigger mammals (sheep, primates). Maternal nutritional manipulations reprogram offspring's adipose tissue resulting in series of alterations: enhanced adipogenesis and lipogenesis, impaired sympathetic activity with reduced noradrenergic innervations and thermogenesis as well as low-grade inflammation. These changes affect adipose tissue development, distribution and composition predisposing offspring to fat accumulation. Modifications of hormonal tissue sensitivity (i.e., leptin, insulin, glucocorticoids) and/or epigenetic mechanisms leading to persistent changes in gene expression may account for long-lasting programming across generations.
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Affiliation(s)
- Simon Lecoutre
- Unité Environnement Périnatal et Santé, UPRES EA 4489, Equipe Malnutrition Maternelle et Programmation des Maladies Métaboliques, Université de Lille Villeneuve d'Ascq, France
| | - Christophe Breton
- Unité Environnement Périnatal et Santé, UPRES EA 4489, Equipe Malnutrition Maternelle et Programmation des Maladies Métaboliques, Université de Lille Villeneuve d'Ascq, France
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102
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Than A, He HL, Chua SH, Xu D, Sun L, Leow MKS, Chen P. Apelin Enhances Brown Adipogenesis and Browning of White Adipocytes. J Biol Chem 2015; 290:14679-91. [PMID: 25931124 DOI: 10.1074/jbc.m115.643817] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 12/17/2022] Open
Abstract
Brown adipose tissue expends energy in the form of heat via the mitochondrial uncoupling protein UCP1. Recent studies showed that brown adipose tissue is present in adult humans and may be exploited for its anti-obesity and anti-diabetes actions. Apelin is an adipocyte-derived hormone that plays important roles in energy metabolism. Here, we report that apelin-APJ signaling promotes brown adipocyte differentiation by increasing the expressions of brown adipogenic and thermogenic transcriptional factors via the PI3K/Akt and AMPK signaling pathways. It is also found that apelin relieves the TNFα inhibition on brown adipogenesis. In addition, apelin increases the basal activity of brown adipocytes, as evidenced by the increased PGC1α and UCP1 expressions, mitochondrial biogenesis, and oxygen consumption. Finally, we provide both in vitro and in vivo evidence that apelin is able to increase the brown-like characteristics in white adipocytes. This study, for the first time, reveals the brown adipogenic and browning effects of apelin and suggests a potential therapeutic route to combat obesity and related metabolic disorders.
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Affiliation(s)
- Aung Than
- From the Bioengineering Program, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| | - Hui Ling He
- From the Bioengineering Program, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| | - Si Hui Chua
- From the Bioengineering Program, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| | - Dan Xu
- the Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, and
| | - Lei Sun
- the Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, and
| | - Melvin Khee-Shing Leow
- the Endocrine and Diabetes Clinic, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
| | - Peng Chen
- From the Bioengineering Program, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457,
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103
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Cell-autonomous activation of Hedgehog signaling inhibits brown adipose tissue development. Proc Natl Acad Sci U S A 2015; 112:5069-74. [PMID: 25848030 DOI: 10.1073/pnas.1420978112] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Although recent studies have shown that brown adipose tissue (BAT) arises from progenitor cells that also give rise to skeletal muscle, the developmental signals that control the formation of BAT remain largely unknown. Here, we show that brown preadipocytes possess primary cilia and can respond to Hedgehog (Hh) signaling. Furthermore, cell-autonomous activation of Hh signaling blocks early brown-preadipocyte differentiation, inhibits BAT formation in vivo, and results in replacement of neck BAT with poorly differentiated skeletal muscle. Finally, we show that Hh signaling inhibits BAT formation partially through up-regulation of chicken ovalbumin upstream promoter transcription factor II (COUP-TFII). Taken together, our studies uncover a previously unidentified role for Hh as an inhibitor of BAT development.
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104
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Abstract
In mammals, a thermogenic mechanism exists that increases heat production and consumes energy. Recent work has shed light on the cellular and physiological mechanisms that control this thermogenic circuit. Thermogenically active adipocytes, namely brown and closely related beige adipocytes, differentiate from progenitor cells that commit to the thermogenic lineage but can arise from different cellular origins. Thermogenic differentiation shares some features with general adipogenesis, highlighting the critical role that common transcription factors may play in progenitors with divergent fates. However, thermogenic differentiation is also discrete from the common adipogenic program and, excitingly, cells with distinct origins possess thermogenic competency that allows them to differentiate into thermogenically active mature adipocytes. An understanding of this thermogenic differentiation program and the factors that can activate it has led to the development of assays that are able to measure thermogenic activity both indirectly and directly. By combining these assays with appropriate cell models, novel therapeutic approaches to combat obesity and its related metabolic disorders by enhancing the thermogenic circuit can be developed.
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Affiliation(s)
- Matthew D Lynes
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Yu-Hua Tseng
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
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105
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Roman S, Agil A, Peran M, Alvaro-Galue E, Ruiz-Ojeda FJ, Fernández-Vázquez G, Marchal JA. Brown adipose tissue and novel therapeutic approaches to treat metabolic disorders. Transl Res 2015; 165:464-79. [PMID: 25433289 DOI: 10.1016/j.trsl.2014.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 10/16/2014] [Accepted: 11/04/2014] [Indexed: 01/08/2023]
Abstract
In humans, 2 functionally different types of adipose tissue coexist: white adipose tissue (WAT) and brown adipose tissue (BAT). WAT is involved in energy storage, whereas BAT is involved in energy expenditure. Increased amounts of WAT may contribute to the development of metabolic disorders, such as obesity-associated type 2 diabetes mellitus and cardiovascular diseases. In contrast, the thermogenic function of BAT allows high consumption of fatty acids because of the activity of uncoupling protein 1 in the internal mitochondrial membrane. Interestingly, obesity reduction and insulin sensitization have been achieved by BAT activation-regeneration in animal models. This review describes the origin, function, and differentiation mechanisms of BAT to identify new therapeutic strategies for the treatment of metabolic disorders related to obesity. On the basis of the animal studies, novel approaches for BAT regeneration combining stem cells from the adipose tissue with active components, such as melatonin, may have potential for the treatment of metabolic disorders in humans.
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Affiliation(s)
- Sabiniano Roman
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Tissue Engineering Group, Kroto Research Institute, University of Sheffield, Sheffield, UK
| | - Ahmad Agil
- Department of Pharmacology and Neurosciences Institute, Faculty of Medicine, Biosanitary Institute of Granada (ibs.GRANADA), Hospitals Unversity/University of Granada, Granada, Spain
| | - Macarena Peran
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Department of Health Sciences, University of Jaén, Jaén, Spain
| | - Eduardo Alvaro-Galue
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Wake Forest Institute for Regenerative Medicine Wake Forest School of Medicine, Winston Salem, NC
| | - Francisco J Ruiz-Ojeda
- Institute of Nutrition and Food Technology, Centre for Biomedical Research, University of Granada, Granada, Spain
| | | | - Juan A Marchal
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Department of Human Anatomy and Embryology, Biosanitary Institute of Granada (ibs.GRANADA), Hospitals Unversity/University of Granada, Granada, Spain.
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106
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Hu X, Luo P, Peng X, Song T, Zhou Y, Wei H, Peng J, Jiang S. Molecular cloning, expression pattern analysis of porcine Rb1 gene and its regulatory roles during primary dedifferentiated fat cells adipogenic differentiation. Gen Comp Endocrinol 2015; 214:77-86. [PMID: 25626122 DOI: 10.1016/j.ygcen.2015.01.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 01/13/2015] [Accepted: 01/19/2015] [Indexed: 11/19/2022]
Abstract
Adipocytes are the main constituent of adipose tissue and are considered to be a corner stone in the homeostatic control of whole body metabolism. Recent reports evidenced that retinoblastoma 1 (Rb1) gene plays an important role in fat development and adipogenesis in mice. Here, we cloned the partial cDNA sequences of the porcine Rb1 gene which contains the complete coding sequences (CDS) of 2820bp encoding a protein of 939 amino acids. Bioinformatic analysis revealed that the CDS of porcine Rb1 was highly identical with those of cattle, human and mice. The porcine Rb1 has three typical conserved structural domains, including Rb-A pocket domain, CYCLIN domain and C-terminus domain, and the phylogenetic tree indicates a closer genetic relationship with cattle and human. Tissue distribution analysis showed that Rb1 expression appeared to be ubiquitously in various tissues, being higher in heart, liver, muscle, and stomach. Furthermore, significant downregulation of Rb1 was found at the initial stage of dedifferentiated fat (DFAT) cells adipogenic differentiation. With the knockdown of the Rb1 expression by siRNA, the number of DFAT cells recruited to white rather than brown adipogenesis was promoted, and mRNA levels of adipogenic markers, such as PPARγ, aP2, LPL and adiponectin and protein expression of PPARγ and adiponectin were increased after hormone stimulation. The underlying mechanisms may be that knockdown of Rb1 promotes the mitotic clonal expansion and PPARγ expression by derepressing the transcriptional activity of E2F so as to facilitate the first steps of adipogenesis. In summary, we cloned and characterized an important negative regulator in adipogenic commitment of porcine DFAT cells.
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Affiliation(s)
- Xiaoming Hu
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, People's Republic of China
| | - Pei Luo
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Xuewu Peng
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Tongxing Song
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Yuanfei Zhou
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Hongkui Wei
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Jian Peng
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, People's Republic of China.
| | - Siwen Jiang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, People's Republic of China.
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107
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Reaves DK, Ginsburg E, Bang JJ, Fleming JM. Persistent organic pollutants and obesity: are they potential mechanisms for breast cancer promotion? Endocr Relat Cancer 2015; 22:R69-86. [PMID: 25624167 PMCID: PMC4352112 DOI: 10.1530/erc-14-0411] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dietary ingestion of persistent organic pollutants (POPs) is correlated with the development of obesity. Obesity alters metabolism, induces an inflammatory tissue microenvironment, and is also linked to diabetes and breast cancer risk/promotion of the disease. However, no direct evidence exists with regard to the correlation among all three of these factors (POPs, obesity, and breast cancer). Herein, we present results from current correlative studies indicating a causal link between POP exposure through diet and their bioaccumulation in adipose tissue that promotes the development of obesity and ultimately influences breast cancer development and/or progression. Furthermore, as endocrine disruptors, POPs could interfere with hormonally responsive tissue functions causing dysregulation of hormone signaling and cell function. This review highlights the critical need for advanced in vitro and in vivo model systems to elucidate the complex relationship among obesity, POPs, and breast cancer, and, more importantly, to delineate their multifaceted molecular, cellular, and biochemical mechanisms. Comprehensive in vitro and in vivo studies directly testing the observed correlations as well as detailing their molecular mechanisms are vital to cancer research and, ultimately, public health.
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Affiliation(s)
- Denise K Reaves
- Department of BiologyNorth Carolina Central University, MTSC Room 2247, 1801 Fayetteville Street, Durham, North Carolina 27707, USANational Cancer InstituteNational Institutes of Health, Center for Cancer Training, Bethesda, Maryland 20892, USADepartment of BiologyNorth Carolina Central University, Durham, North Carolina 27707, USA
| | - Erika Ginsburg
- Department of BiologyNorth Carolina Central University, MTSC Room 2247, 1801 Fayetteville Street, Durham, North Carolina 27707, USANational Cancer InstituteNational Institutes of Health, Center for Cancer Training, Bethesda, Maryland 20892, USADepartment of BiologyNorth Carolina Central University, Durham, North Carolina 27707, USA
| | - John J Bang
- Department of BiologyNorth Carolina Central University, MTSC Room 2247, 1801 Fayetteville Street, Durham, North Carolina 27707, USANational Cancer InstituteNational Institutes of Health, Center for Cancer Training, Bethesda, Maryland 20892, USADepartment of BiologyNorth Carolina Central University, Durham, North Carolina 27707, USA
| | - Jodie M Fleming
- Department of BiologyNorth Carolina Central University, MTSC Room 2247, 1801 Fayetteville Street, Durham, North Carolina 27707, USANational Cancer InstituteNational Institutes of Health, Center for Cancer Training, Bethesda, Maryland 20892, USADepartment of BiologyNorth Carolina Central University, Durham, North Carolina 27707, USA
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108
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Ferrari MD, Klever RR, Terwindt GM, Ayata C, van den Maagdenberg AMJM. Migraine pathophysiology: lessons from mouse models and human genetics. Lancet Neurol 2015; 14:65-80. [PMID: 25496898 DOI: 10.1016/s1474-4422(14)70220-0] [Citation(s) in RCA: 259] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Migraine is a common, disabling, and undertreated episodic brain disorder that is more common in women than in men. Unbiased genome-wide association studies have identified 13 migraine-associated variants pointing at genes that cluster in pathways for glutamatergic neurotransmission, synaptic function, pain sensing, metalloproteinases, and the vasculature. The individual pathogenetic contribution of each gene variant is difficult to assess because of small effect sizes and complex interactions. Six genes with large effect sizes were identified in patients with rare monogenic migraine syndromes, in which hemiplegic migraine and non-hemiplegic migraine with or without aura are part of a wider clinical spectrum. Transgenic mouse models with human monogenic-migraine-syndrome gene mutations showed migraine-like features, increased glutamatergic neurotransmission, cerebral hyperexcitability, and enhanced susceptibility to cortical spreading depression, which is the electrophysiological correlate of aura and a putative trigger for migraine. Enhanced susceptibility to cortical spreading depression increased sensitivity to focal cerebral ischaemia, and blocking of cortical spreading depression improved stroke outcome in these mice. Changes in female hormone levels in these mice modulated cortical spreading depression susceptibility in much the same way that hormonal fluctuations affect migraine activity in patients. These findings confirm the multifactorial basis of migraine and might allow new prophylactic options to be developed, not only for migraine but potentially also for migraine-comorbid disorders such as epilepsy, depression, and stroke.
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Affiliation(s)
- Michel D Ferrari
- Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands.
| | - Roselin R Klever
- Department of Human Genetics, Leiden University Medical Centre, Leiden, Netherlands
| | - Gisela M Terwindt
- Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands
| | - Cenk Ayata
- Department of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Arn M J M van den Maagdenberg
- Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands; Department of Human Genetics, Leiden University Medical Centre, Leiden, Netherlands
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109
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Osteopontin-induced brown adipogenesis from white preadipocytes through a PI3K-AKT dependent signaling. Biochem Biophys Res Commun 2015; 459:553-9. [PMID: 25749339 DOI: 10.1016/j.bbrc.2015.02.153] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 02/25/2015] [Indexed: 11/20/2022]
Abstract
Recent studies have shown that OPN (osteopontin) plays critical roles in cell survival, differentiation, bio-mineralization, cancer and cardiovascular remodeling. However, its roles in the differentiation of brown adipocytes and the underlying mechanisms remain unclear. Therefore, the aim of this study was to investigate the roles of OPN in the brown adipogenesis and the underlying mechanisms. It was shown that the OPN successfully induced the differentiation of 3T3-L1 white preadipocytes into the PRDM16(+) (PRD1-BF1-RIZ1 homologous domain containing 16) and UCP-1(+) (uncoupling protein-1) brown adipocytes in a concentration and time-dependent manner. Also, activation of PI3K (phosphatidylinositol 3-kinase)-AKT pathway was required for the OPN-induced brown adipogenesis. The findings suggest OPN plays an important role in promoting the differentiation of the brown adipocytes and might provide a potential novel therapeutic approach for the treatment of obesity and related disorders.
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110
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Contreras C, Gonzalez F, Fernø J, Diéguez C, Rahmouni K, Nogueiras R, López M. The brain and brown fat. Ann Med 2015; 47:150-68. [PMID: 24915455 PMCID: PMC4438385 DOI: 10.3109/07853890.2014.919727] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 04/25/2014] [Indexed: 02/06/2023] Open
Abstract
Brown adipose tissue (BAT) is a specialized organ responsible for thermogenesis, a process required for maintaining body temperature. BAT is regulated by the sympathetic nervous system (SNS), which activates lipolysis and mitochondrial uncoupling in brown adipocytes. For many years, BAT was considered to be important only in small mammals and newborn humans, but recent data have shown that BAT is also functional in adult humans. On the basis of this evidence, extensive research has been focused on BAT function, where new molecules, such as irisin and bone morphogenetic proteins, particularly BMP7 and BMP8B, as well as novel central factors and new regulatory mechanisms, such as orexins and the canonical ventomedial nucleus of the hypothalamus (VMH) AMP- activated protein kinase (AMPK)-SNS-BAT axis, have been discovered and emerged as potential drug targets to combat obesity. In this review we provide an overview of the complex central regulation of BAT and how different neuronal cell populations co-ordinately work to maintain energy homeostasis.
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Affiliation(s)
- Cristina Contreras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria , Santiago de Compostela, 15782 , Spain
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111
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Hilton C, Karpe F, Pinnick KE. Role of developmental transcription factors in white, brown and beige adipose tissues. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:686-96. [PMID: 25668679 DOI: 10.1016/j.bbalip.2015.02.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/08/2015] [Accepted: 02/03/2015] [Indexed: 02/06/2023]
Abstract
In this review we discuss the role of developmental transcription factors in adipose tissue biology with a focus on how these developmental genes may contribute to regional variation in adipose tissue distribution and function. Regional, depot-specific, differences in lipid handling and signalling (lipolysis, lipid storage and adipokine/lipokine signalling) are important determinants of metabolic health. At a cellular level, preadipocytes removed from their original depot and cultured in vitro retain depot-specific functional properties, implying that these are intrinsic to the cells and not a function of their environment in situ. High throughput screening has identified a number of developmental transcription factors involved in embryological development, including members of the Homeobox and T-Box gene families, that are strongly differentially expressed between regional white adipose tissue depots and also between brown and white adipose tissue. However, the significance of depot-specific developmental signatures remains unclear. Developmental transcription factors determine body patterning during embryogenesis. The divergent developmental origins of regional adipose tissue depots may explain their differing functional characteristics. There is evidence from human genetics that developmental genes determine adipose tissue distribution: in GWAS studies a number of developmental genes have been identified as being correlated with anthropometric measures of adiposity and fat distribution. Additionally, compelling functional studies have recently implicated developmental genes in both white adipogenesis and the so-called 'browning' of white adipose tissue. Understanding the genetic and developmental pathways in adipose tissue may help uncover novel ways to intervene with the function of adipose tissue in order to promote health.
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Affiliation(s)
- Catriona Hilton
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; NIHR Oxford Biomedical Research Centre, OUH Trust, Churchill Hospital, Oxford, UK
| | - Katherine E Pinnick
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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112
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Nguyen KH, Yao XH, Erickson AG, Mishra S, Nyomba BLG. Glucose intolerance in aging male IGFBP-3 transgenic mice: differential effects of human IGFBP-3 and its mutant IGFBP-3 devoid of IGF binding ability. Endocrinology 2015; 156:462-74. [PMID: 25490144 DOI: 10.1210/en.2014-1271] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We have reported a reduction of insulin secretion and glucose intolerance in young mice overexpressing human IGFBP-3 (phosphoglycerate kinase [PGK]BP3) or its mutant Gly56/Gly80/Gly81-IGFBP-3 (PGKmutBP3) under the PGK promoter. Here, we investigated changes in glucose and lipid homeostasis with age in PGKBP3 and PGKmutBP3 mice compared with wild-type mice. Body weight, glucose tolerance, insulin tolerance, visceral fat, interscapular brown adipose tissue (BAT), serum lipids, and pancreas histology were examined at age 3, 6, and 12 months. Murine IGFBP-3 was similar in all mouse genotypes and decreased with age in parallel with total IGF-1. Visceral fat and BAT masses increased in PGKmutBP3 mice, but not in PGKBP3 mice. Glucose tolerance was impaired in both PGKBP3 and PGKmutBP3 mice. However, PGKBP3 mice had increased expression of uncoupling protein-1 in BAT and reduced adiposity, and continued to have smaller pancreatic β-cell mass and reduced insulin secretion through age 12 months. In contrast, PGKmutBP3 mice developed insulin resistance with age in association with pancreatic β-cell hyperplasia, impaired expression of uncoupling protein-1 in BAT, and increased adiposity. In addition, both PGKBP3 and PGKmutBP3 mice had elevated glycerol in the circulation, but only PGKBP3 mice had elevated free fatty acids and only PGKmutBP3 mice had elevated triglycerides. Estimated free IGF-1 did not increase with age in transgenic mice, as it did in wild-type mice. Thus, overexpression of human IGFBP-3 or its mutant devoid of IGF binding ability leads to glucose intolerance with, however, different effects on insulin secretion, insulin sensitivity, and lipid homeostasis in aging mice.
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Affiliation(s)
- K Hoa Nguyen
- Department of Internal Medicine, University of Manitoba, Winnipeg, Canada R3E3P4
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113
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Zhang W, Bi S. Hypothalamic Regulation of Brown Adipose Tissue Thermogenesis and Energy Homeostasis. Front Endocrinol (Lausanne) 2015; 6:136. [PMID: 26379628 PMCID: PMC4553396 DOI: 10.3389/fendo.2015.00136] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/17/2015] [Indexed: 11/18/2022] Open
Abstract
Obesity and diabetes are increasing at an alarming rate worldwide, but the strategies for the prevention and treatment of these disorders remain inadequate. Brown adipose tissue (BAT) is important for cold protection by producing heat using lipids and glucose as metabolic fuels. This thermogenic action causes increased energy expenditure and significant lipid/glucose disposal. In addition, BAT in white adipose tissue (WAT) or beige cells have been found and they also exhibit the thermogenic action similar to BAT. These data provide evidence indicating BAT/beige cells as a potential target for combating obesity and diabetes. Recent discoveries of active BAT and beige cells in adult humans have further highlighted this potential. Growing studies have also shown the importance of central nervous system in the control of BAT thermogenesis and WAT browning using animal models. This review is focused on central neural thermoregulation, particularly addressing our current understanding of the importance of hypothalamic neural signaling in the regulation of BAT/beige thermogenesis and energy homeostasis.
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Affiliation(s)
- Wei Zhang
- Laboratory of Psychiatry and Behavioral Sciences, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- *Correspondence: Wei Zhang, Laboratory of Psychiatry and Behavioral Sciences, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, MD 21205, USA,
| | - Sheng Bi
- Laboratory of Psychiatry and Behavioral Sciences, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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114
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Dinas PC, Nikaki A, Jamurtas AZ, Prassopoulos V, Efthymiadou R, Koutedakis Y, Georgoulias P, Flouris AD. Association between habitual physical activity and brown adipose tissue activity in individuals undergoing PET-CT scan. Clin Endocrinol (Oxf) 2015; 82:147-54. [PMID: 25262810 DOI: 10.1111/cen.12620] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 08/20/2014] [Accepted: 09/20/2014] [Indexed: 01/20/2023]
Abstract
OBJECTIVE Augmented brown adipose tissue (BAT) mass and activity lead to higher basic metabolic rate which is beneficial against obesity. Our aim was to investigate whether habitual (i.e. usual weekly participation) physical activity is linked with BAT activity and mass in humans, in a group of patients undergoing (18) F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scanning. DESIGN Cross-sectional study. PATIENTS Forty patients with cancer [26 male; 14 female; age 52·7 ± 17·5; body mass index (BMI) 26·4 ± 4·5]. MEASUREMENTS Patients completed the 'usual week' form of the International Physical Activity Questionnaire and underwent assessment of BAT activity/mass via (18) F-fluorodeoxyglucose PET/CT. RESULTS We detected a significant association between habitual physical activity (METs-minute/week) and BAT activity [normalized by body weight (BW) (τ = 0·28, P = 0·02), body surface area (BSA) (τ = 0·29, P = 0·02) and lean body mass (LBM) (τ = 0·38, P = 0·002)]. We also found a significant negative relationship between BMI and BAT activity [normalized by BW (τ = -0·30, P = 0·006), BSA (τ = -0·31, P = 0·004) and LBM (τ = -0·45, P = 0·001)] as well as a significant negative relationship between age and BAT activity [normalized by LBM (τ = -0·28, P = 0·01)]. The results also indicate significant differences between low/moderate/high levels of habitual physical activity and BAT activity (P < 0·05). Moreover, BAT activity was different across the BMI categories (normal/overweight/obese) in both sexes (P < 0·05). Finally, BAT activity was greater in women than in men (P < 0·05). CONCLUSIONS Increased participation in habitual physical activity is associated with higher BAT activity. Moreover, individuals with normal BMI demonstrate higher BAT activity compared to overweight and obese individuals. Finally, age is inversely linked with BAT activity, while women demonstrate higher BAT activity than men.
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Affiliation(s)
- Petros C Dinas
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
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115
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Chon SH, Pappas A. Differentiation and characterization of human facial subcutaneous adipocytes. Adipocyte 2015; 4:13-21. [PMID: 26167398 DOI: 10.4161/21623945.2014.955402] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/05/2014] [Accepted: 08/07/2014] [Indexed: 11/19/2022] Open
Abstract
Aging is associated with the loss of facial subcutaneous fat and with increased abdominal subcutaneous fat. Site specific differences in adipocyte phenotype and/or gene expression may play a role in these age-related changes. In this study, we isolated and characterized human facial preadipocytes and investigated distinct metabolic properties such as a differentiation pattern in relation to abdominal preadipocytes. Subcutaneous preadipocytes were isolated from human facial and abdominal skin and cultured in the presence of differentiation factors including rosiglitazone, a known peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist, isobutyl-methyl xanthine (IBMX) and insulin. Differentiation was characterized microscopically and by quantitative real-time PCR. Unexpected superior adipogenic capacity of facial preadipocytes was observed; more facial preadipocytes differentiated in response to rosiglitazone than abdominal preadipocytes and facial preadipocytes retained their ability to differentiate through passage 11 compared with passage 5 for abdominal preadipocytes. Experiments confirmed a reduced lipolysis response in facial versus abdominal adipocytes after exposure to isoproterenol, which was consistent with the reduced β2-adrenergic receptor expression by 60% in the facial cells. The expression of other lipid metabolic gene markers was similar in both facial and abdominal adipocytes with the exception of β3-adrenergic receptor which was only found in abdominal adipose tissue. Gene profiling, by microarray analysis, identified that several HOX genes are robustly reduced in facial adipocytes compared to abdominal adipocytes, suggesting different characteristics between the 2 fat depots. These differences may have implications for development of treatments for facial fat loss during aging.
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116
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Marzolla V, Armani A, Feraco A, De Martino MU, Fabbri A, Rosano G, Caprio M. Mineralocorticoid receptor in adipocytes and macrophages: a promising target to fight metabolic syndrome. Steroids 2014; 91:46-53. [PMID: 24819992 DOI: 10.1016/j.steroids.2014.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 04/29/2014] [Accepted: 05/02/2014] [Indexed: 12/14/2022]
Abstract
Aldosterone is the primary ligand for the mineralocorticoid receptor (MR) and has been considered long time a "renal" hormone, acting at this site as a key regulator of plasma volume, electrolyte homeostasis and blood pressure. A new exciting era of MR biology began with the identification of MR in different non-epithelial tissues such as brain, heart, vessels, macrophages/monocytes, and adipose tissue. The distribution of MR in such a wide range of tissues has suggested novel and unexpected roles for MR, for example in energy metabolism and inflammation. An increasing body of evidence suggests a detrimental effect of aldosterone excess on the development of metabolic alterations. Disturbances in glucose metabolism due to inappropriate activation of MR are frequently observed in patients with primary aldosteronism as well as in obese subjects. MR antagonists have beneficial effects on glucose tolerance and metabolic parameters in experimental animals, whereas their role in humans remains unclear. The aim of this review is to discuss the pathophysiology of MR activation in experimental models, particularly at the level of adipocytes and macrophages, to discuss novel and sometimes contrasting insights from emerging studies, and to highlight deficiencies in the field.
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Affiliation(s)
- Vincenzo Marzolla
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Pisana, Rome, Italy
| | - Andrea Armani
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Pisana, Rome, Italy
| | - Alessandra Feraco
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Pisana, Rome, Italy
| | | | - Andrea Fabbri
- Department of Internal Medicine, Endocrinology Unit, S. Eugenio & CTO A. Alesini Hospitals, University Tor Vergata, Rome, Italy
| | - Giuseppe Rosano
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Pisana, Rome, Italy
| | - Massimiliano Caprio
- Laboratory of Cardiovascular Endocrinology, IRCCS San Raffaele Pisana, Rome, Italy.
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117
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Kim HJ, Cho H, Alexander R, Patterson HC, Gu M, Lo KA, Xu D, Goh VJ, Nguyen LN, Chai X, Huang CX, Kovalik JP, Ghosh S, Trajkovski M, Silver DL, Lodish H, Sun L. MicroRNAs are required for the feature maintenance and differentiation of brown adipocytes. Diabetes 2014; 63:4045-56. [PMID: 25008181 PMCID: PMC4238002 DOI: 10.2337/db14-0466] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Brown adipose tissue (BAT) is specialized to burn lipids for heat generation as a natural defense against cold and obesity. Previous studies established microRNAs (miRNAs) as essential regulators of brown adipocyte differentiation, but whether miRNAs are required for the feature maintenance of mature brown adipocytes remains unknown. To address this question, we ablated Dgcr8, a key regulator of the miRNA biogenesis pathway, in mature brown as well as in white adipocytes. Adipose tissue-specific Dgcr8 knockout mice displayed enlarged but pale interscapular brown fat with decreased expression of genes characteristic of brown fat and were intolerant to cold exposure. Primary brown adipocyte cultures in vitro confirmed that miRNAs are required for marker gene expression in mature brown adipocytes. We also demonstrated that miRNAs are essential for the browning of subcutaneous white adipocytes in vitro and in vivo. Using this animal model, we performed miRNA expression profiling analysis and identified a set of BAT-specific miRNAs that are upregulated during brown adipocyte differentiation and enriched in brown fat compared with other organs. We identified miR-182 and miR-203 as new regulators of brown adipocyte development. Taken together, our study demonstrates an essential role of miRNAs in the maintenance as well as in the differentiation of brown adipocytes.
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Affiliation(s)
- Hye-Jin Kim
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Hyunjii Cho
- Whitehead Institute for Biomedical Research, Cambridge, MA Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Ryan Alexander
- Whitehead Institute for Biomedical Research, Cambridge, MA Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Heide Christine Patterson
- Whitehead Institute for Biomedical Research, Cambridge, MA Department of Pathology, Brigham and Women's Hospital, Boston, MA
| | - Minxia Gu
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | | | - Dan Xu
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Vera J Goh
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Long N Nguyen
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Xiaoran Chai
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Cher X Huang
- Whitehead Institute for Biomedical Research, Cambridge, MA Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Jean-Paul Kovalik
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Sujoy Ghosh
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Mirko Trajkovski
- University of Geneva, Medical Faculty, Department of Cell Physiology and Metabolism, Centre Médical Universitaire (CMU), Geneva, Switzerland
| | - David L Silver
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore
| | - Harvey Lodish
- Whitehead Institute for Biomedical Research, Cambridge, MA Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Lei Sun
- Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, Singapore Institute of Molecular and Cell Biology, Singapore
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118
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DiSilvestro D, Petrosino J, Aldoori A, Melgar-Bermudez E, Wells A, Ziouzenkova O. Enzymatic intracrine regulation of white adipose tissue. Horm Mol Biol Clin Investig 2014; 19:39-55. [PMID: 25390015 DOI: 10.1515/hmbci-2014-0019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 05/28/2014] [Indexed: 11/15/2022]
Abstract
Abdominal fat formation has become a permanent risk factor for metabolic syndrome and various cancers in one-third of the world's population of obese and even lean patients. Formation of abdominal fat involves additional mechanisms beyond an imbalance in energy intake and expenditure, which explains systemic obesity. In this review, we briefly summarized autonomous regulatory circuits that locally produce hormones from inactive precursors or nutrients for intra-/auto-/paracrine signaling in white adipose depots. Enzymatic pathways activating steroid and thyroid hormones in adipose depots were compared with enzymatic production of retinoic acid from vitamin A. We discussed the role of intracrine circuits in fat-depot functions and strategies to reduce abdominal adiposity through thermogenic adipocytes with interrupted generation of retinoic acid.
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119
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Sharma BK, Patil M, Satyanarayana A. Negative regulators of brown adipose tissue (BAT)-mediated thermogenesis. J Cell Physiol 2014; 229:1901-7. [PMID: 24809334 DOI: 10.1002/jcp.24664] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/06/2014] [Indexed: 12/12/2022]
Abstract
Brown adipose tissue (BAT) is specialized for energy expenditure, a process called adaptive thermogenesis. PET-CT scans recently demonstrated the existence of metabolically active BAT in adult humans, which revitalized our interest in BAT. Increasing the amount and/or activity of BAT holds tremendous promise for the treatment of obesity and its associated diseases. PGC1α is the master regulator of UCP1-mediated thermogenesis in BAT. A number of proteins have been identified to influence thermogenesis either positively or negatively through regulating the expression or transcriptional activity of PGC1α. Therefore, BAT activation can be achieved by either inducing the expression of positive regulators of PGC1α or by inhibiting the repressors of the PGC1α/UCP1 pathway. Here, we review the most important negative regulators of PGC1α/UCP1 signaling and their mechanism of action in BAT-mediated thermogenesis.
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Affiliation(s)
- Bal Krishan Sharma
- Department of Biochemistry and Molecular Biology, Molecular Oncology and Biomarkers Program, Georgia Regents University Cancer Center, Georgia Regents University, Augusta, Georgia
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120
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Mehta NK, Mehta KD. Protein kinase C-beta: An emerging connection between nutrient excess and obesity. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1491-1497. [DOI: 10.1016/j.bbalip.2014.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/16/2014] [Accepted: 07/15/2014] [Indexed: 02/06/2023]
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121
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Lecoutre S, Breton C. The cellularity of offspring's adipose tissue is programmed by maternal nutritional manipulations. Adipocyte 2014; 3:256-62. [PMID: 26317049 DOI: 10.4161/adip.29806] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/23/2014] [Accepted: 07/01/2014] [Indexed: 12/17/2022] Open
Abstract
Epidemiological studies initially demonstrated that maternal undernutrition leads to low birth weight with increased risk of adult-onset obesity. Maternal obesity and diabetes associated with high birth weight, excessive nutrition in neonates, and rapid catch-up growth also predispose offspring to fat accumulation. As stated by the Developmental Origin of Health and Disease concept, nutrient supply perturbations in the fetus or neonate result in long-term programming of individual body weight set-point. Adipose tissue is a key fuel storage unit mainly involved in the maintenance of energy homeostasis. Studies in numerous animal models have demonstrated that the adipose tissue is the focus of developmental programming events in a gender- and depot-specific manner. This review summarizes the impact of maternal nutritional manipulations on cellularity (i.e., cell number, size, and type) of adipose tissue in programmed offspring. In rodents, adipose tissue development is particularly active during the perinatal period, especially during the last week of gestation and during early postnatal life. In contrast to rodents, this process essentially takes place before birth in bigger mammals. Despite these different developmental time windows, altricial and precocial species share several mechanisms of adipose tissue programming. Maternal nutritional manipulations result in increased adipogenesis and modified fat distribution and composition. Inflammation changes such as infiltration of macrophages and increased inflammatory markers are also observed. Overall, it may predispose offspring to fat accumulation and obesity. Inappropriate hormone levels, modified tissue sensitivity, and epigenetic mechanisms are key factors involved in the programming of adipose tissue's cellularity during the perinatal period.
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122
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Zhao Y, Ling F, Griffin TM, He T, Towner R, Ruan H, Sun XH. Up-regulation of the Sirtuin 1 (Sirt1) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) genes in white adipose tissue of Id1 protein-deficient mice: implications in the protection against diet and age-induced glucose intolerance. J Biol Chem 2014; 289:29112-22. [PMID: 25190816 DOI: 10.1074/jbc.m114.571679] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Id1, a helix-loop-helix (HLH) protein that inhibits the function of basic HLH E protein transcription factors in lymphoid cells, has been implicated in diet- and age-induced obesity by unknown mechanisms. Here we show that Id1-deficient mice are resistant to a high fat diet- and age-induced obesity, as revealed by reduced weight gain and body fat, increased lipid oxidation, attenuated hepatosteatosis, lower levels of lipid droplets in brown adipose tissue, and smaller white adipocytes after a high fat diet feeding or in aged animals. Id1 deficiency improves glucose tolerance, lowers serum insulin levels, and reduces TNFα gene expression in white adipose tissue. Id1 deficiency also increased expression of Sirtuin 1 and peroxisome proliferator-activated receptor γ coactivator 1α, regulators of mitochondrial biogenesis and energy expenditure, in the white adipose tissue. This effect was accompanied by the elevation of several genes encoding proteins involved in oxidative phosphorylation and fatty acid oxidation, such as cytochrome c, medium-chain acyl-CoA dehydrogenase, and adipocyte protein 2. Moreover, the phenotype for Id1 deficiency was similar to that of mice expressing an E protein dominant-positive construct, ET2, suggesting that the balance between Id and E proteins plays a role in regulating lipid metabolism and insulin sensitivity.
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Affiliation(s)
- Ying Zhao
- From the Program in Immunobiology and Cancer Research
| | - Flora Ling
- From the Program in Immunobiology and Cancer Research, Department of Cell Biology and
| | - Timothy M Griffin
- Program in Free Radical Biology and Aging, and Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | - Ting He
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Hong Ruan
- Department of Physiology and Biophysics, Rutgers University, Piscataway, New Jersey 08854
| | - Xiao-Hong Sun
- From the Program in Immunobiology and Cancer Research, Department of Cell Biology and
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123
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Pfeifer A, Hoffmann LS. Brown, beige, and white: the new color code of fat and its pharmacological implications. Annu Rev Pharmacol Toxicol 2014; 55:207-27. [PMID: 25149919 DOI: 10.1146/annurev-pharmtox-010814-124346] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Brown adipose tissue (BAT) was previously regarded as a special type of fat relevant only for defending hibernating animals and newborns against a cold environment. Recently, BAT has received considerable attention following its (re)discovery in humans. Using glucose tracers, multiple laboratories independently found metabolically active BAT in adults. The enormous metabolic powers of BAT in animal models could make it an attractive target for antiobesity therapies in humans. Here, we review the present knowledge on the role of BAT in energy homeostasis and metabolism, focusing on signaling pathways and potential targets for novel therapeutics. We also shine light on ongoing debates, including those about the true color of brown fat in adults, as well as on the requirements for translation of basic research on BAT into clinical medicine.
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Affiliation(s)
- Alexander Pfeifer
- Institute of Pharmacology and Toxicology, Biomedical Center, University of Bonn, 53105 Bonn, Germany;
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124
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Svensson PA, Lindberg K, Hoffmann JM, Taube M, Pereira MJ, Mohsen-Kanson T, Hafner AL, Rizell M, Palming J, Dani C, Svensson MK. Characterization of brown adipose tissue in the human perirenal depot. Obesity (Silver Spring) 2014; 22:1830-7. [PMID: 24753268 DOI: 10.1002/oby.20765] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 04/03/2014] [Accepted: 04/04/2014] [Indexed: 01/16/2023]
Abstract
OBJECTIVE To characterize brown adipose tissue (BAT) in the human perirenal adipose tissue depot. METHOD Perirenal adipose tissue biopsies were obtained from 55 healthy kidney donors. Expression analysis was performed using microarray, real-time PCR, immunoblotting and immunohistochemistry. Additional studies using human stem cells were performed. RESULTS UCP1 gene expression analysis revealed a large intra-individual variation in the perirenal adipose tissue biopsies. Both multi- and unilocular UCP1-positive adipocytes were detected in several of the adipose tissue samples analyzed by immunohistochemical staining. Microarray analysis identified 54 genes that were overexpressed in UCP1-positive perirenal adipose tissue. Real-time PCR analysis of BAT candidate genes revealed a set of genes that were highly correlated to UCP1 and a set of three transcription factor genes (PRDM16, PGC1α, and RXRγ) that were highly correlated to each other. RXRγ displayed nuclear immunoreactivity in brown adipocytes and an increased gene expression during brown adipogenesis in human stem cells. CONCLUSION Our data provides the first molecular characterization of BAT in the perirenal adipose tissue depot. Furthermore, it highlights the transcription factor RXRγ as a new player in BAT development.
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Affiliation(s)
- Per-Arne Svensson
- Department of Molecular and Clinical Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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125
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Colitti M, Grasso S. Nutraceuticals and regulation of adipocyte life: premises or promises. Biofactors 2014; 40:398-418. [PMID: 24692086 DOI: 10.1002/biof.1164] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/26/2014] [Accepted: 03/16/2014] [Indexed: 01/18/2023]
Abstract
Obesity is the actual worldwide health threat, that is associated with an increased number of metabolic disorders and diseases. Following the traditional hypothesis stating that in obesity hypertrophic adipocytes trigger the adipose tissue hyperplasia, strategies to treat obesity have increased fat researches of the molecular processes that achieve adipocyte enlargement and formation that finally increase body fat mass. Moreover, a new cell type was recently identified, the "brite" adipocyte that presents a unique gene expression profile of compared to both brown and white adipocytes. Therapies against obesity, targeting these cells and their pathways, would include the induction of lipolysis and apoptosis or the inhibition of differentiation and adipogenesis. However, it should be noted that both the increase of adipocyte size and number take place in association with positive energy balance. According to the adipose tissue expansion hypothesis, adipogenesis could be related with improved metabolic health of obese people, taking back the adipose mass to a traditionally site of lipid storage. Furthermore, new perspectives in fat biology suggest that the conversion of white-to-brown adipocytes and their metabolism could be exploited for the development of therapeutic approaches against obesity-associated diseases and for the regulation of energy balance. Drugs currently available to treat obesity generally have unpleasant side effects. A novel promising approach is the usage of dietary supplements and plant products that could interfere on the life cycle of adipocyte. Here, various dietary bioactive compounds that target different stages of adipocyte life cycle and molecular and metabolic pathways are reviewed.
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Affiliation(s)
- Monica Colitti
- Department of Agricultural and Environmental Sciences, University of Udine, Udine, Italy
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126
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Li Y, Bolze F, Fromme T, Klingenspor M. Intrinsic differences in BRITE adipogenesis of primary adipocytes from two different mouse strains. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1345-52. [PMID: 24953778 DOI: 10.1016/j.bbalip.2014.06.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 05/16/2014] [Accepted: 06/08/2014] [Indexed: 12/22/2022]
Abstract
BRITE (brown-in-white) cells are brown adipocyte-like cells found in white adipose tissue (WAT) of rodents and/or humans. The recruitment of BRITE adipocytes, referred to as the browning of WAT, is hallmarked by the expression of UCP1 and exerts beneficial metabolic effects. Here we address whether beyond systemic cues depot- and strain-specific variation in BRITE recruitment is determined by a cellular program intrinsic to progenitors. Therefore we compared the browning capacity of serum and investigated brown and BRITE adipogenesis in primary cultures of stromal-vascular cells isolated from interscapular brown adipose tissue (iBAT), inguinal white adipose tissue (iWAT) and epididymal white adipose tissue (eWAT) in two inbred mouse strains C57BL/6J (B6, a strain with low browning propensity) and 129/S6SvEv (129, a strain with high browning propensity). Paradoxically, serum collected from B6 mice was more potent in the promotion of browning than serum collected from 129 mice. Nevertheless, we demonstrate that depot- and strain-specific differences observed in vivo are pheno-copied in primary cultures in vitro, as judged by UCP1 expression and by functional analysis. Notably, primary adipocytes from 129 mice had a higher capacity for isoproterenol-induced uncoupled respiration than B6. We conclude that cues intrinsic to the progenitor cells contribute to differential BRITE adipogenesis. Further analyses demonstrate that these cues are independent of autocrine/paracrine mechanisms, BRITE progenitor abundance and genetic variation in the gene regulatory region of Ucp1 but rather depend on trans-acting factors. These results provide new insights on the molecular basis of strain and depot-specific differences in BRITE adipogenesis.
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Affiliation(s)
- Yongguo Li
- Molecular Nutritional Medicine, Technische Universität München, Else Kröner-Fresenius Center, Freising, Germany
| | - Florian Bolze
- Molecular Nutritional Medicine, Technische Universität München, Else Kröner-Fresenius Center, Freising, Germany
| | - Tobias Fromme
- Molecular Nutritional Medicine, Technische Universität München, Else Kröner-Fresenius Center, Freising, Germany
| | - Martin Klingenspor
- Molecular Nutritional Medicine, Technische Universität München, Else Kröner-Fresenius Center, Freising, Germany.
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Mehta KD. Emerging role of protein kinase C in energy homeostasis: A brief overview. World J Diabetes 2014; 5:385-392. [PMID: 24936260 PMCID: PMC4058743 DOI: 10.4239/wjd.v5.i3.385] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 04/16/2014] [Indexed: 02/05/2023] Open
Abstract
Protein kinase C-β (PKCβ), a member of the lipid-activated serine/threonine PKC family, has been implicated in a wide range of important cellular processes. Very recently, the novel role of PKCβ in the regulation of triglyceride homeostasis via regulating mitochondrial function has been explored. In this review, I aim to provide an overview of PKCβ regarding regulation by lipids and recently gained knowledge on its role in energy homeostasis. Alterations in adipose PKCβ expression have been shown to be crucial for diet-induced obesity and related metabolic abnormalities. High-fat diet is shown to induce PKCβ expression in white adipose tissue in an isoform- and tissue-specific manner. Genetically manipulated mice devoid of PKCβ are lean with increased oxygen consumption and are resistant to high-fat diet-induced obesity and hepatic steatosis with improved insulin sensitivity. Available data support the model in which PKCβ functions as a “diet-sensitive” metabolic sensor whose induction in adipose tissue by high-fat diet is among the initiating event disrupting mitochondrial homeostasis via intersecting with p66Shc signaling to amplify adipose dysfunction and have systemic consequences. Alterations in PKCβ expression and/or function may have important implications in health and disease and warrants a detailed investigation into the downstream target genes and the underlying mechanisms involved. Development of drugs that target the PKCβ pathway and identification of miRs specifically controlling PKCβ expression may lead to novel therapeutic options for treating age-related metabolic disease including fatty liver, obesity and type 2 diabetes.
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128
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Patil M, Sharma BK, Satyanarayana A. Id transcriptional regulators in adipogenesis and adipose tissue metabolism. Front Biosci (Landmark Ed) 2014; 19:1386-97. [PMID: 24896358 DOI: 10.2741/4289] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Id proteins (Id1-Id4) are helix-loop-helix (HLH) transcriptional regulators that lack a basic DNA binding domain. They act as negative regulators of basic helix-loop-helix (bHLH) transcription factors by forming heterodimers and inhibit their DNA binding and transcriptional activity. Id proteins are implicated in the regulation of various cellular mechanisms such as cell proliferation, cellular differentiation, cell fate determination, angiogenesis and tumorigenesis. A handful of recent studies also disclosed that Id proteins have critical functions in adipocyte differentiation and adipose tissue metabolism. Here, we reviewed the progress made thus far in understanding the specific functions of Id proteins in adipose tissue differentiation and metabolism. In addition to reviewing the known mechanisms of action, we also discuss possible additional mechanisms in which Id proteins might participate in regulating adipogenic and metabolic pathways.
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129
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Shen Y, Liu X, Dong M, Lin J, Zhao Q, Lee H, Jin W. Recent advances in brown adipose tissue biology. CHINESE SCIENCE BULLETIN-CHINESE 2014. [DOI: 10.1007/s11434-014-0386-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Lim MA, Bence KK, Sandesara I, Andreux P, Auwerx J, Ishibashi J, Seale P, Kalb RG. Genetically altering organismal metabolism by leptin-deficiency benefits a mouse model of amyotrophic lateral sclerosis. Hum Mol Genet 2014; 23:4995-5008. [PMID: 24833719 DOI: 10.1093/hmg/ddu214] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, neurodegenerative disease that causes death of motor neurons. ALS patients and mouse models of familial ALS display organismal level metabolic dysfunction, which includes increased energy expenditure despite decreased lean mass. The pathophysiological relevance of abnormal energy homeostasis to motor neuron disease remains unclear. Leptin is an adipocyte-derived hormone that regulates whole-animal energy expenditure. Here, we report that placing mutant superoxide dismutase 1 (SOD1) mice in a leptin-deficient background improves energy homeostasis and slows disease progression. Leptin-deficient mutant SOD1 mice possess increased bodyweight and fat mass, as well as decreased energy expenditure. These observations coincide with enhanced survival, improved strength and decreased motor neuron loss. These results suggest that altering whole-body energy metabolism in mutant SOD1 mice can mitigate disease progression. We propose that manipulations that increase fat mass and reduce energy expenditure will be beneficial in the setting of motor neuron disease.
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Affiliation(s)
- Maria A Lim
- Division of Neurology, Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA, Neuroscience Graduate Group
| | - Kendra K Bence
- Neuroscience Graduate Group, Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ishani Sandesara
- Division of Neurology, Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Pénélope Andreux
- Laboratory for Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Johan Auwerx
- Laboratory for Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jeff Ishibashi
- Institute for Diabetes, Obesity and Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Patrick Seale
- Institute for Diabetes, Obesity and Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert G Kalb
- Division of Neurology, Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA, Neuroscience Graduate Group, Department of Neurology and
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131
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Identification of Hipk2 as an essential regulator of white fat development. Proc Natl Acad Sci U S A 2014; 111:7373-8. [PMID: 24785298 DOI: 10.1073/pnas.1322275111] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Homeodomain-interacting protein kinase 2 (Hipk2) has previously been implicated in the control of several transcription factors involved in embryonic development, apoptosis, cell proliferation, and tumor development, but very little is understood about the exact mechanisms through which Hipk2 influences these processes. Analysis of gene expression in normal tissues from genetically heterogeneous mouse or human populations can reveal network motifs associated with the structural or functional components of the tissue, and may predict roles for genes of unknown function. Here we have applied this network strategy to uncover a role for the Hipk2 gene in the transcriptional system controlling adipogenesis. Both in vitro and in vivo models were used to show that knockdown or loss of Hipk2 specifically inhibits white adipose cell differentiation and tissue development. In addition, loss of Hipk2 leads to induction of pockets of multilocular brown fat-like cells in remaining white adipose depots, which express markers of brown and beige fat such as uncoupling protein 1 and transmembrane protein 26. These changes are accompanied by increased insulin sensitivity in Hipk2 knockout mice and reduced high-fat diet-induced weight gain, highlighting a potential role for this kinase in diseases such as diabetes and obesity. Our study underscores the versatility and power of a readily available tissue, such as skin, for network modeling of systemic transcriptional programs involved in multiple pathways, including lipid metabolism and adipogenesis.
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132
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Tarantal AF, Berglund L. Obesity and lifespan health--importance of the fetal environment. Nutrients 2014; 6:1725-36. [PMID: 24763115 PMCID: PMC4011063 DOI: 10.3390/nu6041725] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 04/09/2014] [Accepted: 04/15/2014] [Indexed: 02/02/2023] Open
Abstract
A marked increase in the frequency of obesity at the population level has resulted in an increasing number of obese women entering pregnancy. The increasing realization of the importance of the fetal environment in relation to chronic disease across the lifespan has focused attention on the role of maternal obesity in fetal development. Previous studies have demonstrated that obesity during adolescence and adulthood can be traced back to fetal and early childhood exposures. This review focuses on factors that contribute to early developmental events, such as epigenetic modifications, the potential for an increase in inflammatory burden, early developmental programming changes such as the variable development of white versus brown adipose tissue, and alterations in organ ontogeny. We hypothesize that these mechanisms promote an unfavorable fetal environment and can have a long-standing impact, with early manifestations of chronic disease that can result in an increased demand for future health care. In order to identify appropriate preventive measures, attention needs to be placed both on reducing maternal obesity as well as understanding the molecular, cellular, and epigenetic mechanisms that may be responsible for the prenatal onset of chronic disease.
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Affiliation(s)
- Alice F Tarantal
- Department of Pediatrics, School of Medicine, University of California, Davis, CA 95616, USA.
| | - Lars Berglund
- Department of Medicine, School of Medicine, University of California, Davis, CA 95616, USA.
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133
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Abstract
There has been an upsurge of interest in the adipocyte coincident with the onset of the obesity epidemic and the realization that adipose tissue plays a major role in the regulation of metabolic function. The past few years, in particular, have seen significant changes in the way that we classify adipocytes and how we view adipose development and differentiation. We have new perspective on the roles played by adipocytes in a variety of homeostatic processes and on the mechanisms used by adipocytes to communicate with other tissues. Finally, there has been significant progress in understanding how these relationships are altered during metabolic disease and how they might be manipulated to restore metabolic health.
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Affiliation(s)
- Evan D Rosen
- Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Departments of Genetics and Cell Biology, Harvard Medical School, Boston, MA 02215, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
| | - Bruce M Spiegelman
- Departments of Genetics and Cell Biology, Harvard Medical School, Boston, MA 02215, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
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134
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Fan X, Wang J, Fan W, Chen L, Gui B, Tan G, Zhou J. Replication of Migraine GWAS Susceptibility Loci in Chinese Han Population. Headache 2014; 54:709-15. [PMID: 24666033 DOI: 10.1111/head.12329] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2014] [Indexed: 12/13/2022]
Affiliation(s)
- Xiaoping Fan
- Hospice; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
| | - Jing Wang
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
| | - Wen Fan
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
| | - Lixue Chen
- Laboratory Research Center; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
| | - Bei Gui
- Laboratory Research Center; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
| | - Ge Tan
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
| | - Jiying Zhou
- Department of Neurology; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
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135
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Geerling JJ, Boon MR, van der Zon GC, van den Berg SAA, van den Hoek AM, Lombès M, Princen HMG, Havekes LM, Rensen PCN, Guigas B. Metformin lowers plasma triglycerides by promoting VLDL-triglyceride clearance by brown adipose tissue in mice. Diabetes 2014; 63:880-91. [PMID: 24270984 DOI: 10.2337/db13-0194] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Metformin is the first-line drug for the treatment of type 2 diabetes. Besides its well-characterized antihyperglycemic properties, metformin also lowers plasma VLDL triglyceride (TG). In this study, we investigated the underlying mechanisms in APOE*3-Leiden.CETP mice, a well-established model for human-like lipoprotein metabolism. We found that metformin markedly lowered plasma total cholesterol and TG levels, an effect mostly due to a decrease in VLDL-TG, whereas HDL was slightly increased. Strikingly, metformin did not affect hepatic VLDL-TG production, VLDL particle composition, and hepatic lipid composition but selectively enhanced clearance of glycerol tri[(3)H]oleate-labeled VLDL-like emulsion particles into brown adipose tissue (BAT). BAT mass and lipid droplet content were reduced in metformin-treated mice, pointing to increased BAT activation. In addition, both AMP-activated protein kinase α1 (AMPKα1) expression and activity and HSL and mitochondrial content were increased in BAT. Furthermore, therapeutic concentrations of metformin increased AMPK and HSL activities and promoted lipolysis in T37i differentiated brown adipocytes. Collectively, our results identify BAT as an important player in the TG-lowering effect of metformin by enhancing VLDL-TG uptake, intracellular TG lipolysis, and subsequent mitochondrial fatty acid oxidation. Targeting BAT might therefore be considered as a future therapeutic strategy for the treatment of dyslipidemia.
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Affiliation(s)
- Janine J Geerling
- Department of General Internal Medicine, Endocrinology, and Metabolic Diseases, Leiden University Medical Center, Leiden, the Netherlands
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136
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Simonson MA, McQueen MB, Keller MC. Whole-genome pathway analysis on 132,497 individuals identifies novel gene-sets associated with body mass index. PLoS One 2014; 9:e78546. [PMID: 24497910 PMCID: PMC3908858 DOI: 10.1371/journal.pone.0078546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 09/14/2013] [Indexed: 01/28/2023] Open
Abstract
Whole genome pathway analysis is a powerful tool for the exploration of the combined effects of gene-sets within biological pathways. This study applied Interval Based Enrichment Analysis (INRICH) to perform whole-genome pathway analysis of body-mass index (BMI). We used a discovery set composed of summary statistics from a meta-analysis of 123,865 subjects performed by the GIANT Consortium, and an independent sample of 8,632 subjects to assess replication of significant pathways. We examined SNPs within nominally significant pathways using linear mixed models to estimate their contribution to overall BMI heritability. Six pathways replicated as having significant enrichment for association after correcting for multiple testing, including the previously unknown relationships between BMI and the Reactome regulation of ornithine decarboxylase pathway, the KEGG lysosome pathway, and the Reactome stabilization of P53 pathway. Two non-overlapping sets of genes emerged from the six significant pathways. The clustering of shared genes based on previously identified protein-protein interactions listed in PubMed and OMIM supported the relatively independent biological effects of these two gene-sets. We estimate that the SNPs located in examined pathways explain ∼20% of the heritability for BMI that is tagged by common SNPs (3.35% of the 16.93% total).
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Affiliation(s)
- Matthew A. Simonson
- Department of Psychology and Neuroscience, Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, United States of America
- Mayo Clinic, Department of Health Sciences, Division of Biomedical Statistics and Informatics, Rochester, Minnesota, United States of America
- * E-mail:
| | - Matthew B. McQueen
- Department of Integrative Physiology, Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, United States of America
| | - Matthew C. Keller
- Department of Psychology and Neuroscience, Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, United States of America
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137
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Lin JC, Tarn WY, Hsieh WK. Emerging role for RNA binding motif protein 4 in the development of brown adipocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:769-79. [PMID: 24389249 DOI: 10.1016/j.bbamcr.2013.12.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 12/21/2013] [Accepted: 12/24/2013] [Indexed: 10/25/2022]
Abstract
RNA-binding motif protein 4 (RBM4) reportedly reprograms the tissue-specific splicing network which modulates the development of muscles and pancreatic β-islets. Herein, we report that Rbm4a(-/-) mice exhibited hyperlipidemia accompanied with reduced mass of interscapular brown adipose tissue (iBAT). Elevated RBM4a led to the isoform shift of IR, Ppar-γ, and Pref-1 genes which play pivotal roles in the different stages of adipogenesis. Overexpression of RBM4a enhanced the mitochondrial activity of brown adipocyte-like lineage in the presence of uncoupling agent. RBM4a-ablated adipocytes inversely exhibited impaired development and inefficient energy expenditure. Intriguingly, overexpressed RBM4a induced the expression of brown adipocyte-specific factors (Prdm16 and Bmp7) in white adipocyte-like lineage, which suggested the potential action of RBM4a on the white-to-brown trans-differentiation of adipocytes. In differentiating adipocytes, RBM4a constituted a feed-forward circuit through autoregulating the splicing pattern of its own transcript. Based on these results, we propose the emerging role of RBM4 in regulating the adipocyte-specific splicing events and transcription cascade, which subsequently facilitate the development and function of brown adipocyte-like cells.
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Affiliation(s)
- Jung-Chun Lin
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Wen-Kou Hsieh
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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138
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Abstract
Adipose tissue plays a major role in metabolic homeostasis, which it coordinates through a number of local and systemic effectors. The burgeoning epidemic of metabolic disease, especially obesity and type 2 diabetes, has focused attention on the adipocyte. In this chapter, we review strategies for genetic overexpression and knockout of specific genes in adipose tissue. We also discuss these strategies in the context of different types of adipocytes, including brown, beige, and white fat cells.
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Affiliation(s)
- Sona Kang
- Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Xingxing Kong
- Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Evan D Rosen
- Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA.
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139
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Okamatsu-Ogura Y, Fukano K, Tsubota A, Uozumi A, Terao A, Kimura K, Saito M. Thermogenic ability of uncoupling protein 1 in beige adipocytes in mice. PLoS One 2013; 8:e84229. [PMID: 24386355 PMCID: PMC3875535 DOI: 10.1371/journal.pone.0084229] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/21/2013] [Indexed: 01/09/2023] Open
Abstract
Chronic adrenergic activation leads to the emergence of beige adipocytes in some depots of white adipose tissue in mice. Despite their morphological similarities to brown adipocytes and their expression of uncoupling protein 1 (UCP1), a thermogenic protein exclusively expressed in brown adipocytes, the beige adipocytes have a gene expression pattern distinct from that of brown adipocytes. However, it is unclear whether the thermogenic function of beige adipocytes is different from that of classical brown adipocytes existing in brown adipose tissue. To examine the thermogenic ability of UCP1 expressed in beige and brown adipocytes, the adipocytes were isolated from the fat depots of C57BL/6J mice housed at 24°C (control group) or 10°C (cold-acclimated group) for 3 weeks. Morphological and gene expression analyses revealed that the adipocytes isolated from brown adipose tissue of both the control and cold-acclimated groups consisted mainly of brown adipocytes. These brown adipocytes contained large amounts of UCP1 and increased their oxygen consumption when stimulated with norepinephirine. Adipocytes isolated from the perigonadal white adipose tissues of both groups and the inguinal white adipose tissue of the control group were white adipocytes that showed no increase in oxygen consumption after norepinephrine stimulation. Adipocytes isolated from the inguinal white adipose tissue of the cold-acclimated group were a mixture of white and beige adipocytes, which expressed UCP1 and increased their oxygen consumption in response to norepinephrine. The UCP1 content and thermogenic ability of beige adipocytes estimated on the basis of their abundance in the cell mixture were similar to those of brown adipocytes. These results revealed that the inducible beige adipocytes have potent thermogenic ability comparable to classical brown adipocytes.
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Affiliation(s)
- Yuko Okamatsu-Ogura
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
- * E-mail:
| | - Keigo Fukano
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Ayumi Tsubota
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Akihiro Uozumi
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Akira Terao
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Kazuhiro Kimura
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Masayuki Saito
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
- Department of Nutrition, Graduate School of Nursing and Nutrition, Tenshi College, Sapporo, Japan
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140
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miR-155 regulates differentiation of brown and beige adipocytes via a bistable circuit. Nat Commun 2013; 4:1769. [PMID: 23612310 PMCID: PMC3644088 DOI: 10.1038/ncomms2742] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 03/15/2013] [Indexed: 12/11/2022] Open
Abstract
Brown adipocytes are a primary site of energy expenditure and reside not only in classical brown adipose tissue but can also be found in white adipose tissue. Here we show that microRNA 155 is enriched in brown adipose tissue and is highly expressed in proliferating brown preadipocytes but declines after induction of differentiation. Interestingly, microRNA 155 and its target, the adipogenic transcription factor CCAAT/enhancer-binding protein β, form a bistable feedback loop integrating hormonal signals that regulate proliferation or differentiation. Inhibition of microRNA 155 enhances brown adipocyte differentiation and induces a brown adipocyte-like phenotype (‘browning’) in white adipocytes. Consequently, microRNA 155-deficient mice exhibit increased brown adipose tissue function and ‘browning’ of white fat tissue. In contrast, transgenic overexpression of microRNA 155 in mice causes a reduction of brown adipose tissue mass and impairment of brown adipose tissue function. These data demonstrate that the bistable loop involving microRNA 155 and CCAAT/enhancer-binding protein β regulates brown lineage commitment, thereby, controlling the development of brown and beige fat cells. Brown fat can dissipate energy as heat and has an important role in energy homoeostasis of rodents and possibly humans. Chen et al. show that microRNA 155 regulates the differentiation of brown adipocytes as well as the 'browning' of white fat cells in mice.
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141
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Abstract
Adipose tissue is formed at stereotypic times and locations in a diverse array of organisms. Once formed, the tissue is dynamic, responding to homeostatic and external cues and capable of a 15-fold expansion. The formation and maintenance of adipose tissue is essential to many biological processes and when perturbed leads to significant diseases. Despite this basic and clinical significance, understanding of the developmental biology of adipose tissue has languished. In this Review, we highlight recent efforts to unveil adipose developmental cues, adipose stem cell biology and the regulators of adipose tissue homeostasis and dynamism.
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Affiliation(s)
- Daniel C Berry
- Department of Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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142
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Lukaszewski MA, Eberlé D, Vieau D, Breton C. Nutritional manipulations in the perinatal period program adipose tissue in offspring. Am J Physiol Endocrinol Metab 2013; 305:E1195-207. [PMID: 24045869 DOI: 10.1152/ajpendo.00231.2013] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Epidemiological studies demonstrated initially that maternal undernutrition results in low birth weight with increased risk for long-lasting energy balance disorders. Maternal obesity and diabetes associated with high birth weight, excessive nutrition in neonates, and rapid catchup growth also increase the risk of adult-onset obesity. As stated by the Developmental Origin of Health and Disease concept, nutrient supply perturbations in the fetus or neonate result in long-term programming of individual body weight set point. Adipose tissue is a key fuel storage unit involved mainly in the maintenance of energy homeostasis. Studies in numerous animal models have demonstrated that the adipose tissue is the focus of developmental programming events in a sex- and depot-specific manner. In rodents, adipose tissue development is particularly active during the perinatal period, especially during the last week of gestation and during early postnatal life. In contrast to rodents, this process essentially takes place before birth in bigger mammals. Despite these different developmental time windows, altricial and precocial species share several mechanisms of adipose tissue programming. Offspring from malnourished dams present adipose tissue with a series of alterations: impaired glucose uptake, insulin and leptin resistance, low-grade inflammation, modified sympathetic activity with reduced noradrenergic innervations, and thermogenesis. These modifications reprogram adipose tissue metabolism by changing fat distribution and composition and by enhancing adipogenesis, predisposing the offspring to fat accumulation. Subtle adipose tissue circadian rhythm changes are also observed. Inappropriate hormone levels, modified tissue sensitivity (especially glucocorticoid system), and epigenetic mechanisms are key factors for adipose tissue programming during the perinatal period.
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Affiliation(s)
- Marie-Amélie Lukaszewski
- Unité Environnement Périnatal et Croissance, UPRES EA 4489, Equipe Dénutritions Maternelles Périnatales, Université Lille-Nord de France, Villeneuve d'Ascq, France
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143
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Conover CA, Harstad SL, Tchkonia T, Kirkland JL. Preferential impact of pregnancy-associated plasma protein-A deficiency on visceral fat in mice on high-fat diet. Am J Physiol Endocrinol Metab 2013; 305:E1145-53. [PMID: 24045868 PMCID: PMC3840208 DOI: 10.1152/ajpendo.00405.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Accumulation of visceral fat, more so than subcutaneous fat, is strongly associated with severe metabolic complications. However, the factors regulating depot-specific adipogenesis are poorly understood. In this study, we show differential expression of pregnancy-associated plasma protein-A (PAPP-A), a secreted regulator of local insulin-like growth factor (IGF) action, in adipose tissue of mice. PAPP-A mRNA expression was fivefold higher in visceral (mesenteric) fat compared with subcutaneous (inguinal, subscapular), perirenal, and brown fat of mice. To investigate the possible role of depot-specific PAPP-A expression in fat accumulation, wild-type (WT) and PAPP-A knockout (KO) mice were fed a high-fat diet (HFD) for up to 20 wk. Adipocyte size increased in subcutaneous and perirenal depots similarly in WT and PAPP-A KO mice. However, fat cell size and in vivo lipid uptake were significantly reduced in mesenteric fat of PAPP-A KO compared with WT mice. After 20 wk on HFD, phosphorylation of AKT, a downstream signaling intermediate of IGF-I and insulin receptor activation, was significantly decreased by 50% in mesenteric compared with subcutaneous fat in WT mice, but was significantly increased threefold in mesenteric compared with subcutaneous fat in PAPP-A KO mice. This appeared to be because of enhanced insulin-stimulated signaling in mesenteric fat of PAPP-A KO mice. These data establish fat depot-specific expression of PAPP-A and indicate preferential impact of PAPP-A deficiency on visceral fat in the mouse that is associated with enhanced insulin receptor signaling. Thus, PAPP-A may be a potential target for treatment and/or prevention strategies for visceral obesity and related morbidities.
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Affiliation(s)
- Cheryl A Conover
- Division of Endocrinology, Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota; and
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144
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Kamal AHM, Kim WK, Cho K, Park A, Min JK, Han BS, Park SG, Lee SC, Bae KH. Investigation of adipocyte proteome during the differentiation of brown preadipocytes. J Proteomics 2013; 94:327-36. [PMID: 24129212 DOI: 10.1016/j.jprot.2013.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/02/2013] [Accepted: 10/01/2013] [Indexed: 02/07/2023]
Abstract
UNLABELLED Brown adipocytes oxidize fatty acids to produce heat in response to cold or caloric overfeeding. The motivation and function of the development of brown fat may thus counteract obesity, though this remains uncertain. We investigated the brown adipocyte proteome by two-dimensional gel electrophoresis followed by mass spectrometry. Comparative analyses of proteins focused on total protein spots to filter differentially expressed proteins during the differentiation of mouse primary brown preadipocytes. A Western blot analysis was performed to verify the target proteins. The results indicated that 10 protein spots were differentially expressed with significant changes, including the three up-regulated proteins of prohibitin, hypoxanthine-guanine phosphoribosyltransferase, and enoyl-CoA hydratase protein; the 5 down-regulated proteins of triosephosphate isomerase, elongation factor 2, α-tropomyosin slow, endophilin-B1, and cofilin-1 (CFL1); and the two unequivocally expressed proteins of peroxiredoxin-1 and collagen α-1(i) chain precursor. We found that during brown adipogenesis, CFL1 has an inhibitory effect on brown adipocyte differentiation. The overexpression of CFL1 inhibited the brown fat deposition and repressed the brown marker genes UCP1, PRDM16, PGC-1α and PPARγ via actin dynamics and polymerization. These observations may be novel findings that bring new insight into the detailed mechanisms of brown adipogenesis and identify possible therapeutic targets for anti-obesity. BIOLOGICAL SIGNIFICANCE We use 2-DE to compare the proteomes of adipocytes during the brown adipogenesis of primary mouse preadipocytes. We identified 10 proteins that are differentially expressed. Among these, we found that the actin binding protein CFL1 inhibits the differentiation of brown preadipocytes. CFL1 overexpressing cells showed lower deposition of brown fat droplets, and the brown marker genes of UCP1, PRDM16, PGC-1α and PPARγ were decreased through actin dynamics and polymerization.
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Affiliation(s)
- Abu Hena Mostafa Kamal
- Research Center for Integrated Cellulomics, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Republic of Korea
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145
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Schumacher MA, Chinnam N, Ohashi T, Shah RS, Erickson HP. The structure of irisin reveals a novel intersubunit β-sheet fibronectin type III (FNIII) dimer: implications for receptor activation. J Biol Chem 2013; 288:33738-33744. [PMID: 24114836 DOI: 10.1074/jbc.m113.516641] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Irisin was recently identified as a putative myokine that is induced by exercise. Studies suggest that it is produced by cleavage of the FNDC5 (fibronectin domain-containing protein 5) receptor; irisin corresponds to the extracellular receptor ectodomain. Data suggesting that irisin stimulates white-to-brown fat conversion have led to the hypothesis that it does so by binding an unknown receptor, thus functioning as a myokine. As brown fat promotes energy dissipation, myokines that elicit the transformation of white to brown fat have potentially profound benefits in the treatment of obesity and metabolic disorders. Understanding the molecular basis for such exercise-induced phenomena is thus of considerable interest. Moreover, FNDC5-like receptors are highly conserved and have been shown to be critical for neuronal development. However, the structural and molecular mechanisms utilized by these proteins are currently unknown. Here, we describe the crystal structure and biochemical characterization of the FNDC5 ectodomain, corresponding to the irisin myokine. The 2.28 Å structure shows that irisin consists of an N-terminal fibronectin III (FNIII)-like domain attached to a flexible C-terminal tail. Strikingly, the FNIII-like domain forms a continuous intersubunit β-sheet dimer, previously unobserved for any FNIII protein. Biochemical data confirm that irisin is a dimer and that dimerization is unaffected by glycosylation. This finding suggests a possible mechanism for receptor activation by the irisin domain as a preformed myokine dimer ligand or as a paracrine or autocrine dimerization module on FNDC5-like receptors.
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Affiliation(s)
- Maria A Schumacher
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710.
| | - Nagababu Chinnam
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710
| | - Tomoo Ohashi
- Department of Cell Biology and Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710
| | - Riddhi Sanjay Shah
- Department of Cell Biology and Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710
| | - Harold P Erickson
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710; Department of Cell Biology and Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710
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146
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Symonds ME, Budge H, Frazier-Wood AC. Epigenetics and obesity: a relationship waiting to be explained. Hum Hered 2013; 75:90-7. [PMID: 24081224 DOI: 10.1159/000352009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Obesity can have multifactorial causes that may change with development and are not simply attributable to one's genetic constitution. To date, expensive and laborious genome-wide association studies have only ascribed a small contribution of genetic variants to obesity. The emergence of the field of epigenetics now offers a new paradigm with which to study excess fat mass. Currently, however, there are no compelling epigenetic studies to explain the role of epigenetics in obesity, especially from a developmental perspective. It is clear that until there are advances in the understanding of the main mechanisms by which different fat types, i.e. brown, beige, and white, are established and how these differ between depots and species, population-based studies designed to determine specific aspects of epigenetics will be potentially limited. Obesity is a slowly evolving condition that is not simply explained by changes in the intake of one macronutrient. The latest advances in epigenetics, coupled with the establishment of relevant longitudinal models of obesity, which incorporate functionally relevant end points, may now permit the precise contribution of epigenetic modifications to excess fat mass to be effectively studied.
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Affiliation(s)
- Michael E Symonds
- Early Life Nutrition Research Unit, Academic Division of Child Health, School of Medicine, University Hospital, The University of Nottingham, Nottingham, UK
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147
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Abstract
Obesity represents a major risk factor for the development of several of our most common medical conditions, including Type 2 diabetes, dyslipidaemia, non-alcoholic fatty liver, cardiovascular disease and even some cancers. Although increased fat mass is the main feature of obesity, not all fat depots are created equal. Adipocytes found in white adipose tissue contain a single large lipid droplet and play well-known roles in energy storage. By contrast, brown adipose tissue is specialized for thermogenic energy expenditure. Owing to its significant capacity to dissipate energy and regulate triacylglycerol (triglyceride) and glucose metabolism, and its demonstrated presence in adult humans, brown fat could be a potential target for the treatment of obesity and metabolic syndrome. Undoubtedly, fundamental knowledge about the formation of brown fat and regulation of its activity is imperatively needed to make such therapeutics possible. In the present review, we integrate the recent advancements on the regulation of brown fat formation and activity by developmental and hormonal signals in relation to its metabolic function.
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148
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Li S, Yu Q, Wang GX, Lin JD. The biological clock is regulated by adrenergic signaling in brown fat but is dispensable for cold-induced thermogenesis. PLoS One 2013; 8:e70109. [PMID: 23990898 PMCID: PMC3753278 DOI: 10.1371/journal.pone.0070109] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 06/17/2013] [Indexed: 11/19/2022] Open
Abstract
The biological clock plays an important role in integrating nutrient and energy metabolism with other cellular processes. Previous studies have demonstrated that core clock genes are rhythmically expressed in peripheral tissues, including the liver, skeletal muscle, pancreatic islets, and white and brown adipose tissues. These peripheral clocks are entrained by physiological cues, thereby aligning the circadian pacemaker to tissue functions. The mechanisms that regulate brown adipose tissue clock in response to physiological signals remain poorly understood. Here we found that the expression of core clock genes is highly responsive to cold exposure in brown fat, but not in white fat. This cold-inducible regulation of the clock network is mediated by adrenergic receptor activation and the transcriptional coactivator PGC-1α. Brown adipocytes in mice lacking a functional clock contain large lipid droplets accompanied by dysregulation of genes involved in lipid metabolism and adaptive thermogenesis. Paradoxically, the "clockless" mice were competent in maintaining core body temperature during cold exposure. These studies elucidated the presence of adrenergic receptor/clock crosstalk that appears to be required for normal thermogenic gene expression in brown fat.
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Affiliation(s)
- Siming Li
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Qi Yu
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Guo-Xiao Wang
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jiandie D. Lin
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
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149
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Zimmerman HA, Olson KC, Chen G, Lynch CJ. Adipose transplant for inborn errors of branched chain amino acid metabolism in mice. Mol Genet Metab 2013; 109:345-53. [PMID: 23800641 PMCID: PMC3955948 DOI: 10.1016/j.ymgme.2013.05.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 11/24/2022]
Abstract
Liver transplantation appears to be quite beneficial for treatment of maple syrup urine disease (MSUD, an inherited disorder of branched chain amino acid metabolism); however, there is a limited availability of donor livers worldwide and the first year costs of liver transplants are quite high. Recent studies have suggested that intact adipose tissue, already widely used in reconstructive surgery, may have an underappreciated high capacity for branched chain amino acid (BCAA) metabolism. Here we examined the potential for adipose tissue transplant to lower circulating BCAAs in two models of defective BCAA metabolism, BCATm and PP2Cm [branched chain keto acid dehydrogenase complex (BCKDC) phosphatase] knockout (KO) mice. After 1-2g fat transplant, BCATm and PP2Cm KO mice gained or maintained body weight 3weeks after surgery and consumed similar or more food/BCAAs the week before phlebotomy. Transplant of fat into the abdominal cavity led to a sterile inflammatory response and nonviable transplanted tissue. However when 1-2g of fat was transplanted subcutaneously into the back, either as small (0.1-0.3g) or finely minced pieces introduced with an 18-ga. needle, plasma BCAAs decreased compared to Sham operated mice. In two studies on BCATm KO mice and one study on PP2Cm KO mice, fat transplant led to 52-81% reductions in plasma BCAAs compared to baseline plasma BCAA concentrations of untreated WT type siblings. In PP2Cm KO mice, individual BCAAs in plasma were also significantly reduced by fat transplant, as were the alloisoleucine/Phe ratios. Therefore, subcutaneous fat transplantation may have merit as an adjunct to dietary treatment of MSUD. Additional studies are needed to further refine this approach.
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Affiliation(s)
- Heather A. Zimmerman
- Department of Comparative Medicine, Penn State University College of Medicine, 500 University Dr., Hershey, PA 17033, USA
| | - Kristine C. Olson
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, 500 University Dr., Hershey, PA 17033, USA
| | - Gang Chen
- Department of Public Health Sciences, Penn State University College of Medicine, 500 University Dr., Hershey, PA 17033, USA
- The Macromolecular Core Facility, Penn State University College of Medicine, 500 University Dr., Hershey, PA 17033, USA
| | - Christopher J. Lynch
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, 500 University Dr., Hershey, PA 17033, USA
- Correspondence: Christopher J. Lynch, Ph.D., Dept. of Cellular & Molecular Physiology, Penn State College of Medicine. 500 University Drive, MC-H166, Hershey, PA 17033, USA FAX: +1 717 531 7667,
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150
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Peterson JM, Wei Z, Seldin MM, Byerly MS, Aja S, Wong GW. CTRP9 transgenic mice are protected from diet-induced obesity and metabolic dysfunction. Am J Physiol Regul Integr Comp Physiol 2013; 305:R522-33. [PMID: 23842676 DOI: 10.1152/ajpregu.00110.2013] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CTRP9 is a secreted multimeric protein of the C1q family and the closest paralog of the insulin-sensitizing adipokine, adiponectin. The metabolic function of this adipose tissue-derived plasma protein remains largely unknown. Here, we show that the circulating levels of CTRP9 are downregulated in diet-induced obese mice and upregulated upon refeeding. Overexpressing CTRP9 resulted in lean mice that dramatically resisted weight gain induced by a high-fat diet, largely through decreased food intake and increased basal metabolism. Enhanced fat oxidation in CTRP9 transgenic mice resulted from increases in skeletal muscle mitochondrial content, expression of enzymes involved in fatty acid oxidation (LCAD and MCAD), and chronic AMPK activation. Hepatic and skeletal muscle triglyceride levels were substantially decreased in transgenic mice. Consequently, CTRP9 transgenic mice had a greatly improved metabolic profile with markedly reduced fasting insulin and glucose levels. The high-fat diet-induced obesity, insulin resistance, and hepatic steatosis observed in wild-type mice were prevented in transgenic mice. Consistent with the in vivo data, recombinant protein significantly enhanced fat oxidation in L6 myotubes via AMPK activation and reduced lipid accumulation in H4IIE hepatocytes. Collectively, these data establish CTRP9 as a novel metabolic regulator and a new component of the metabolic network that links adipose tissue to lipid metabolism in skeletal muscle and liver.
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Affiliation(s)
- Jonathan M Peterson
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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