401
|
Ost M, Coleman V, Voigt A, van Schothorst EM, Keipert S, van der Stelt I, Ringel S, Graja A, Ambrosi T, Kipp AP, Jastroch M, Schulz TJ, Keijer J, Klaus S. Muscle mitochondrial stress adaptation operates independently of endogenous FGF21 action. Mol Metab 2015; 5:79-90. [PMID: 26909316 PMCID: PMC4735627 DOI: 10.1016/j.molmet.2015.11.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 11/02/2015] [Accepted: 11/09/2015] [Indexed: 12/31/2022] Open
Abstract
Objective Fibroblast growth factor 21 (FGF21) was recently discovered as stress-induced myokine during mitochondrial disease and proposed as key metabolic mediator of the integrated stress response (ISR) presumably causing systemic metabolic improvements. Curiously, the precise cell-non-autonomous and cell-autonomous relevance of endogenous FGF21 action remained poorly understood. Methods We made use of the established UCP1 transgenic (TG) mouse, a model of metabolic perturbations made by a specific decrease in muscle mitochondrial efficiency through increased respiratory uncoupling and robust metabolic adaptation and muscle ISR-driven FGF21 induction. In a cross of TG with Fgf21-knockout (FGF21−/−) mice, we determined the functional role of FGF21 as a muscle stress-induced myokine under low and high fat feeding conditions. Results Here we uncovered that FGF21 signaling is dispensable for metabolic improvements evoked by compromised mitochondrial function in skeletal muscle. Strikingly, genetic ablation of FGF21 fully counteracted the cell-non-autonomous metabolic remodeling and browning of subcutaneous white adipose tissue (WAT), together with the reduction of circulating triglycerides and cholesterol. Brown adipose tissue activity was similar in all groups. Remarkably, we found that FGF21 played a negligible role in muscle mitochondrial stress-related improved obesity resistance, glycemic control and hepatic lipid homeostasis. Furthermore, the protective cell-autonomous muscle mitohormesis and metabolic stress adaptation, including an increased muscle proteostasis via mitochondrial unfolded protein response (UPRmt) and amino acid biosynthetic pathways did not require the presence of FGF21. Conclusions Here we demonstrate that although FGF21 drives WAT remodeling, the adaptive pseudo-starvation response under elevated muscle mitochondrial stress conditions operates independently of both WAT browning and FGF21 action. Thus, our findings challenge FGF21 as key metabolic mediator of the mitochondrial stress adaptation and powerful therapeutic target during muscle mitochondrial disease. Muscle mitochondrial stress-induced browning of white adipose tissue fully requires FGF21. Negligible role of myokine FGF21 on whole body metabolic adaptations. Muscle mitohormesis and starvation-like response operates independently of FGF21 action.
Collapse
Affiliation(s)
- Mario Ost
- Research Group Physiology of Energy Metabolism, German Institute of Human Nutrition, Nuthetal, 14558, Germany.
| | - Verena Coleman
- Research Group Physiology of Energy Metabolism, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| | - Anja Voigt
- Research Group Physiology of Energy Metabolism, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| | | | - Susanne Keipert
- Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Inge van der Stelt
- Human and Animal Physiology, Wageningen University, Wageningen, 6708, Netherlands
| | - Sebastian Ringel
- Research Group Physiology of Energy Metabolism, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| | - Antonia Graja
- Research Group Adipocyte Development, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| | - Thomas Ambrosi
- Research Group Adipocyte Development, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| | - Anna P Kipp
- Department of Molecular Toxicology, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| | - Martin Jastroch
- Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Tim J Schulz
- Research Group Adipocyte Development, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, Wageningen, 6708, Netherlands
| | - Susanne Klaus
- Research Group Physiology of Energy Metabolism, German Institute of Human Nutrition, Nuthetal, 14558, Germany
| |
Collapse
|
402
|
Sanchez-Delgado G, Martinez-Tellez B, Olza J, Aguilera CM, Labayen I, Ortega FB, Chillon P, Fernandez-Reguera C, Alcantara JM, Martinez-Avila WD, Muñoz-Hernandez V, Acosta FM, Prados-Ruiz J, Amaro-Gahete FJ, Hidalgo-Garcia L, Rodriguez L, Ruiz YAK, Ramirez-Navarro A, Muros-de Fuentes MA, García-Rivero Y, Sanchez-Sanchez R, de Dios Beas Jimenez J, de Teresa C, Navarrete S, Lozano R, Brea-Gomez E, Rubio-Lopez J, Ruiz MR, Cano-Nieto A, Llamas-Elvira JM, Jimenez Rios JA, Gil A, Ruiz JR. Activating brown adipose tissue through exercise (ACTIBATE) in young adults: Rationale, design and methodology. Contemp Clin Trials 2015; 45:416-425. [DOI: 10.1016/j.cct.2015.11.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 10/28/2015] [Accepted: 11/01/2015] [Indexed: 01/04/2023]
|
403
|
Schnyder S, Handschin C. Skeletal muscle as an endocrine organ: PGC-1α, myokines and exercise. Bone 2015; 80:115-125. [PMID: 26453501 PMCID: PMC4657151 DOI: 10.1016/j.bone.2015.02.008] [Citation(s) in RCA: 262] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 01/27/2015] [Accepted: 02/08/2015] [Indexed: 12/29/2022]
Abstract
An active lifestyle is crucial to maintain health into old age; inversely, sedentariness has been linked to an elevated risk for many chronic diseases. The discovery of myokines, hormones produced by skeletal muscle tissue, suggests the possibility that these might be molecular mediators of the whole body effects of exercise originating from contracting muscle fibers. Even though less is known about the sedentary state, the lack of contraction-induced myokines or the production of a distinct set of hormones in the inactive muscle could likewise contribute to pathological consequences in this context. In this review, we try to summarize the most recent developments in the study of muscle as an endocrine organ and speculate about the potential impact on our understanding of exercise and sedentary physiology, respectively. This article is part of a Special Issue entitled "Muscle Bone Interactions".
Collapse
Affiliation(s)
- Svenia Schnyder
- Biozentrum, Div. of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
| | - Christoph Handschin
- Biozentrum, Div. of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland.
| |
Collapse
|
404
|
Wang Y, Liu Z, Zou W, Hong H, Fang H, Tong W. Molecular regulation of miRNAs and potential biomarkers in the progression of hepatic steatosis to NASH. Biomark Med 2015; 9:1189-200. [DOI: 10.2217/bmm.15.70] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence suggests that microRNAs regulate diverse biological functions in the liver and play a very important function in metabolic-related disorders such as nonalcoholic fatty liver disease via regulating their target genes expression. In this review, we summarized the most recent progress in identification of miRNAs involving in the progression of liver steatosis and discussed the possible mechanisms by which miRNAs contribute to the diverse pathogenic liver injuries. We provide insights into the functional network of miRNAs by connecting miRNAs, their targets and biological pathways associated to hepatic steatosis and fibrosis, with important implications for our understanding of phenotypic-based disease pathogenesis. We also discuss the possible roles and challenges of miRNAs as biomarkers for drug-induced liver injury.
Collapse
Affiliation(s)
- Yuping Wang
- Division of Bioinformatics & Biostatistics, National Center for Toxicological Research, US FDA, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Zhichao Liu
- Division of Bioinformatics & Biostatistics, National Center for Toxicological Research, US FDA, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Wen Zou
- Division of Bioinformatics & Biostatistics, National Center for Toxicological Research, US FDA, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Huixiao Hong
- Division of Bioinformatics & Biostatistics, National Center for Toxicological Research, US FDA, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Hong Fang
- Office of Scientific Coordination, National Center for Toxicological Research, US FDA, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Weida Tong
- Division of Bioinformatics & Biostatistics, National Center for Toxicological Research, US FDA, 3900 NCTR Road, Jefferson, AR 72079, USA
| |
Collapse
|
405
|
Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity. Mol Cell Biol 2015; 36:184-96. [PMID: 26503783 DOI: 10.1128/mcb.00722-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/12/2015] [Indexed: 01/26/2023] Open
Abstract
Mitochondrial oxidative and thermogenic functions in brown and beige adipose tissues modulate rates of energy expenditure. It is unclear, however, how beige or white adipose tissue contributes to brown fat thermogenic function or compensates for partial deficiencies in this tissue and protects against obesity. Here, we show that the transcription factor Yin Yang 1 (YY1) in brown adipose tissue activates the canonical thermogenic and uncoupling gene expression program. In contrast, YY1 represses a series of secreted proteins, including fibroblast growth factor 21 (FGF21), bone morphogenetic protein 8b (BMP8b), growth differentiation factor 15 (GDF15), angiopoietin-like 6 (Angptl6), neuromedin B, and nesfatin, linked to energy expenditure. Despite substantial decreases in mitochondrial thermogenic proteins in brown fat, mice lacking YY1 in this tissue are strongly protected against diet-induced obesity and exhibit increased energy expenditure and oxygen consumption in beige and white fat depots. The increased expression of secreted proteins correlates with elevation of energy expenditure and promotion of beige and white fat activation. These results indicate that YY1 in brown adipose tissue controls antagonistic gene expression programs associated with energy balance and maintenance of body weight.
Collapse
|
406
|
Rodríguez A, Ezquerro S, Méndez-Giménez L, Becerril S, Frühbeck G. Revisiting the adipocyte: a model for integration of cytokine signaling in the regulation of energy metabolism. Am J Physiol Endocrinol Metab 2015; 309:E691-714. [PMID: 26330344 DOI: 10.1152/ajpendo.00297.2015] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 08/24/2015] [Indexed: 02/08/2023]
Abstract
Adipose tissue constitutes an extremely active endocrine organ with a network of signaling pathways enabling the organism to adapt to a wide range of different metabolic challenges, such as starvation, stress, infection, and short periods of gross energy excess. The functional pleiotropism of adipose tissue relies on its ability to synthesize and release a huge variety of hormones, cytokines, complement and growth factors, extracellular matrix proteins, and vasoactive factors, collectively termed adipokines. Obesity is associated with adipose tissue dysfunction leading to the onset of several pathologies including type 2 diabetes, dyslipidemia, nonalcoholic fatty liver, or hypertension, among others. The mechanisms underlying the development of obesity and its associated comorbidities include the hypertrophy and/or hyperplasia of adipocytes, adipose tissue inflammation, impaired extracellular matrix remodeling, and fibrosis together with an altered secretion of adipokines. Recently, the potential role of brown and beige adipose tissue in the protection against obesity has been also recognized. In contrast to white adipocytes, which store energy in the form of fat, brown and beige fat cells display energy-dissipating capacity through the promotion of triacylglycerol clearance, glucose disposal, and generation of heat for thermogenesis. Identification of the morphological and molecular changes in white, beige, and brown adipose tissue during weight gain is of utmost relevance for the identification of pharmacological targets for the treatment of obesity and its associated metabolic diseases.
Collapse
Affiliation(s)
- Amaia Rodríguez
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Silvia Ezquerro
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain
| | - Leire Méndez-Giménez
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Sara Becerril
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Gema Frühbeck
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona, Spain; Department of Endocrinology and Nutrition, Clínica Universidad de Navarra, Pamplona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain; and Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| |
Collapse
|
407
|
Abstract
Since brown adipose tissue (BAT) dissipates energy through UCP1, BAT has garnered attention as a therapeutic intervention for obesity and metabolic diseases including type 2 diabetes. As we better understand the physiological roles of classical brown and beige adipocytes, it is becoming clear that BAT is not simply a heat-generating organ. Increased beige fat mass in response to a variety of external/internal cues is associated with significant improvements in glucose and lipid homeostasis that may not be entirely mediated by UCP1. We aim to discuss recent insights regarding the developmental lineages, molecular regulation, and new functions for brown and beige adipocytes.
Collapse
Affiliation(s)
- Shingo Kajimura
- UCSF Diabetes Center and Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143-0669, USA.
| | - Bruce M Spiegelman
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA.
| | - Patrick Seale
- Institute for Diabetes, Obesity, and Metabolism, Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
408
|
Roberts LD. Does inorganic nitrate say NO to obesity by browning white adipose tissue? Adipocyte 2015; 4:311-4. [PMID: 26451288 DOI: 10.1080/21623945.2015.1005525] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/02/2015] [Accepted: 01/05/2015] [Indexed: 12/28/2022] Open
Abstract
The dietary constituent inorganic nitrate, found in large concentrations in green leafy vegetables, has beneficial effects on cardiometabolic health. Contemporary studies employing nitrate have demonstrated that the anion has anti-obesity and anti-diabetic properties; however the nitrate-mediated mechanisms for improving metabolic health remain unclear. Recently, we employed a combined histological, metabolomics, and transcriptional and protein analysis approach to establish that nitrate promoted the "browning" of white adipose tissue via the xanthine oxidoreductase catalyzed reductive nitrate-nitrite-nitric oxide pathway. Interestingly, it was observed that nitrate-stimulated brown adipose-associated gene expression in white adipose tissue was augmented in hypoxia. These findings not only suggest that protection from metabolic disease offered by vegetable consumption may, in part, be mediated through the effects of nitrate on white adipose tissue, but also, since hypoxia is a serious co-morbidity affecting adipose tissue in obese individuals, that nitrate may be effective in promoting the browning of adipose tissue to improve metabolic fitness.
Collapse
|
409
|
Abstract
Many organisms have developed a robust ability to adapt and survive in the face of environmental perturbations that threaten the integrity of their genome, proteome, or metabolome. Studies in multiple model organisms have shown that, in general, when exposed to stress, cells activate a complex prosurvival signaling network that includes immune and DNA damage response genes, chaperones, antioxidant enzymes, structural proteins, metabolic enzymes, and noncoding RNAs. The manner of activation runs the gamut from transcriptional induction of genes to increased stability of transcripts to posttranslational modification of important biosynthetic proteins within the stressed tissue. Superimposed on these largely autonomous effects are nonautonomous responses in which the stressed tissue secretes peptides and other factors that stimulate tissues in different organs to embark on processes that ultimately help the organism as a whole cope with stress. This review focuses on the mechanisms by which tissues in one organ adapt to environmental challenges by regulating stress responses in tissues of different organs.
Collapse
Affiliation(s)
- Edward Owusu-Ansah
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY 10032;
| | | |
Collapse
|
410
|
Mu Q, Fang X, Li X, Zhao D, Mo F, Jiang G, Yu N, Zhang Y, Guo Y, Fu M, Liu JL, Zhang D, Gao S. Ginsenoside Rb1 promotes browning through regulation of PPARγ in 3T3-L1 adipocytes. Biochem Biophys Res Commun 2015; 466:530-5. [PMID: 26381176 DOI: 10.1016/j.bbrc.2015.09.064] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 11/30/2022]
Abstract
Browning of white adipocyte tissue (WAT) has received considerable attention due to its potential implication in preventing obesity and related comorbidities. Ginsenoside Rb1 is reported to improve glycolipid metabolism and reduce body weight in obese animals. However whether the body reducing effect mediates by browning effect remains unclear. For this purpose, 3T3-L1 adipocytes were used to study the effect of ginsenoside Rb1 on browning adipocytes specific genes and oxygen consumptions. The results demonstrate that 10 μM of ginsenoside Rb1 increases basal glucose uptake and promoted browning evidenced by significant increases in mRNA expressions of UCP-1, PGC-1α and PRDM16 in 3T3-L1 mature adipocytes. Further, ginsenoside Rb1 also increases PPARγ activity. And the browning effect is abrogated by GW9692, a PPARγ antagonist. In addition, ginsenoside Rb1 increases basal respiration rate, ATP production and uncoupling capacity in 3T3-L1 adipocytes. Those effects are also blunted by GW9692. The results suggest that ginsenoside Rb1 promote browning of 3T3-L1 adipocytes through induction of PPARγ. Our finding offer a new source to discover browning agonists and also useful to understand and extend the applications of ginseng and its constituents.
Collapse
Affiliation(s)
- Qianqian Mu
- Preclinical Medicine School, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Xin Fang
- Preclinical Medicine School, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Xiaoke Li
- Preclinical Medicine School, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Dandan Zhao
- Diabetes Research Center, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Fangfang Mo
- Diabetes Research Center, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Guangjian Jiang
- Diabetes Research Center, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Na Yu
- Preclinical Medicine School, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Yi Zhang
- Preclinical Medicine School, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Yubo Guo
- Preclinical Medicine School, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Min Fu
- The Research Institute of McGill University Health Center, Montreal, Quebec H4A 3J1, Canada
| | - Jun-Li Liu
- The Research Institute of McGill University Health Center, Montreal, Quebec H4A 3J1, Canada
| | - Dongwei Zhang
- Diabetes Research Center, Beijing University of Chinese Medicine, Beijing 100029, China.
| | - Sihua Gao
- Diabetes Research Center, Beijing University of Chinese Medicine, Beijing 100029, China.
| |
Collapse
|
411
|
Brown adipose tissue: a potential target in the fight against obesity and the metabolic syndrome. Clin Sci (Lond) 2015; 129:933-49. [DOI: 10.1042/cs20150339] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BAT (brown adipose tissue) is the main site of thermogenesis in mammals. It is essential to ensure thermoregulation in newborns. It is also found in (some) adult humans. Its capacity to oxidize fatty acids and glucose without ATP production contributes to energy expenditure and glucose homoeostasis. Brown fat activation has thus emerged as an attractive therapeutic target for the treatment of obesity and the metabolic syndrome. In the present review, we integrate the recent advances on the metabolic role of BAT and its relation with other tissues as well as its potential contribution to fighting obesity and the metabolic syndrome.
Collapse
|
412
|
Martínez-Redondo V, Pettersson AT, Ruas JL. The hitchhiker's guide to PGC-1α isoform structure and biological functions. Diabetologia 2015; 58:1969-77. [PMID: 26109214 DOI: 10.1007/s00125-015-3671-z] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/03/2015] [Indexed: 12/16/2022]
Abstract
Proteins of the peroxisome proliferator-activated receptor γ (PPARγ) coactivator 1 (PGC-1) family of transcriptional coactivators coordinate physiological adaptations in many tissues, usually in response to demands for higher nutrient and energy supply. Of the founding members of the family, PGC-1α (also known as PPARGC1A) is the most highly regulated gene, using multiple promoters and alternative splicing to produce a growing number of coactivator variants. PGC-1α promoters are selectively active in distinct tissues in response to specific stimuli. To date, more than ten novel PGC-1α isoforms have been reported to be expressed from a novel promoter (PGC-1α-b, PGC-1α-c), to undergo alternative splicing (NT-PGC-1α) or both (PGC-1α2, PGC-1α3, PGC-1α4). The resulting proteins display differential regulation and tissue distribution and, most importantly, exert specific biological functions. In this review we discuss the structural and functional characteristics of the novel PGC-1α isoforms, aiming to provide an integrative view of this constantly expanding system of transcriptional coactivators.
Collapse
Affiliation(s)
- Vicente Martínez-Redondo
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177, Stockholm, Sweden
| | | | | |
Collapse
|
413
|
Jung TW, Hwang HJ, Hong HC, Yoo HJ, Baik SH, Choi KM. BAIBA attenuates insulin resistance and inflammation induced by palmitate or a high fat diet via an AMPK-PPARδ-dependent pathway in mice. Diabetologia 2015; 58:2096-105. [PMID: 26105792 DOI: 10.1007/s00125-015-3663-z] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/21/2015] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS We explored the effects of β-aminoisobutyric acid (BAIBA) on hyperlipidaemic-condition-induced insulin resistance and inflammation as mediated through a signalling pathway involving AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor δ (PPARδ). METHODS Mouse skeletal muscle C2C12 cells and C57BL/6J mice were treated with palmitate or a high-fat diet (HFD) and BAIBA. Inflammation and the expression of genes associated with insulin signalling were determined by western blot and quantitative real-time PCR. Selected genes from candidate pathways were evaluated by small interfering (si)RNA knockdown and specific inhibitors. RESULTS BAIBA treatment ameliorated impairment of insulin receptor substrate (IRS)-1/Akt-mediated insulin signalling in palmitate-treated C2C12 myocytes and in skeletal muscle of HFD-fed mice. In addition, BAIBA treatment reversed HFD-induced increases in body weight and improved impaired glucose tolerance in mice. In vitro and in vivo, inhibitory κBα (IκBα) phosphorylation, nuclear factor κB (NFκB) nuclear translocation and downstream inflammatory cytokines were significantly suppressed by BAIBA. Furthermore, BAIBA treatment significantly induced AMPK phosphorylation and expression of PPARδ in C2C12 myocytes and in skeletal muscle of mice. Both compound C, an AMPK inhibitor, and Pparδ (also known as Ppard) siRNA abrogated the inhibitory effects of BAIBA on palmitate-induced inflammation and insulin resistance. BAIBA significantly induced the expression of genes associated with fatty acid oxidation, such as carnitine palmitoyltransferase 1 (Cpt1), acyl-CoA oxidase (Aco; also known as Acox1) and fatty acid binding protein 3 (Fabp3); this effect of BAIBA was significantly reduced by compound C and Pparδ siRNA. CONCLUSIONS/INTERPRETATION These results are the first to demonstrate that BAIBA attenuates insulin resistance, suppresses inflammation and induces fatty acid oxidation via the AMPK-PPARδ pathway in skeletal muscle.
Collapse
Affiliation(s)
- Tae Woo Jung
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University Guro Hospital, 80 Guro-Dong, Guro-Gu, Seoul, 152-050, Republic of Korea
| | | | | | | | | | | |
Collapse
|
414
|
Merlin J, Evans BA, Dehvari N, Sato M, Bengtsson T, Hutchinson DS. Could burning fat start with a brite spark? Pharmacological and nutritional ways to promote thermogenesis. Mol Nutr Food Res 2015. [DOI: 10.1002/mnfr.201500251] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jon Merlin
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Australia
| | - Bronwyn A. Evans
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Australia
| | - Nodi Dehvari
- Department of Molecular Biosciences; The Wenner-Gren Institute; Stockholm University; Stockholm Sweden
| | - Masaaki Sato
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Australia
- Department of Pharmacology; Monash University; Clayton Australia
| | - Tore Bengtsson
- Department of Molecular Biosciences; The Wenner-Gren Institute; Stockholm University; Stockholm Sweden
| | - Dana S. Hutchinson
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Australia
- Department of Pharmacology; Monash University; Clayton Australia
| |
Collapse
|
415
|
Chriett S, Pirola L. Essential roles of four-carbon backbone chemicals in the control of metabolism. World J Biol Chem 2015; 6:223-230. [PMID: 26322177 PMCID: PMC4549763 DOI: 10.4331/wjbc.v6.i3.223] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/27/2015] [Accepted: 05/18/2015] [Indexed: 02/05/2023] Open
Abstract
The increasing incidence of obesity worldwide and its related cardiometabolic complications is an urgent public health problem. While weight gain results from a negative balance between the energy expenditure and calorie intake, recent research has demonstrated that several small organic molecules containing a four-carbon backbone can modulate this balance by favoring energy expenditure, and alleviating endoplasmic reticulum stress and oxidative stress. Such small molecules include the bacterially produced short chain fatty acid butyric acid, its chemically produced derivative 4-phenylbutyric acid, the main ketone body D-β-hydroxybutyrate - synthesized by the liver - and the recently discovered myokine β-aminoisobutyric acid. Conversely, another butyrate-related molecule, α-hydroxybutyrate, has been found to be an early predictor of insulin resistance and glucose intolerance. In this minireview, we summarize recent advances in the understanding of the mechanism of action of these molecules, and discuss their use as therapeutics to improve metabolic homeostasis or their detection as early biomarkers of incipient insulin resistance.
Collapse
|
416
|
McNally B, Griffin JL, Roberts LD. Dietary inorganic nitrate: From villain to hero in metabolic disease? Mol Nutr Food Res 2015; 60:67-78. [PMID: 26227946 PMCID: PMC4863140 DOI: 10.1002/mnfr.201500153] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/13/2015] [Accepted: 07/23/2015] [Indexed: 12/22/2022]
Abstract
Historically, inorganic nitrate was believed to be an inert by‐product of nitric oxide (NO) metabolism that was readily excreted by the body. Studies utilising doses of nitrate far in excess of dietary and physiological sources reported potentially toxic and carcinogenic effects of the anion. However, nitrate is a significant component of our diets, with the majority of the anion coming from green leafy vegetables, which have been consistently shown to offer protection against obesity, type 2 diabetes and metabolic diseases. The discovery of a metabolic pathway in mammals, in which nitrate is reduced to NO, via nitrite, has warranted a re‐examination of the physiological role of this small molecule. Obesity, type 2 diabetes and the metabolic syndrome are associated with a decrease in NO bioavailability. Recent research suggests that the nitrate‐nitrite‐NO pathway may be harnessed as a therapeutic to supplement circulating NO concentrations, with both anti‐obesity and anti‐diabetic effects, as well as improving vascular function. In this review, we examine the key studies that have led to the re‐evaluation of the physiological function of inorganic nitrate, from toxic and carcinogenic metabolite, to a potentially important and beneficial agent in the treatment of metabolic disease.
Collapse
Affiliation(s)
- Ben McNally
- Elsie Widdowson Laboratory, Medical Research Council - Human Nutrition Research, Cambridge, UK.,Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Julian L Griffin
- Elsie Widdowson Laboratory, Medical Research Council - Human Nutrition Research, Cambridge, UK.,Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Lee D Roberts
- Elsie Widdowson Laboratory, Medical Research Council - Human Nutrition Research, Cambridge, UK.,Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| |
Collapse
|
417
|
Hansen JS, Zhao X, Irmler M, Liu X, Hoene M, Scheler M, Li Y, Beckers J, Hrabĕ de Angelis M, Häring HU, Pedersen BK, Lehmann R, Xu G, Plomgaard P, Weigert C. Type 2 diabetes alters metabolic and transcriptional signatures of glucose and amino acid metabolism during exercise and recovery. Diabetologia 2015; 58:1845-54. [PMID: 26067360 DOI: 10.1007/s00125-015-3584-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/13/2015] [Indexed: 12/24/2022]
Abstract
AIMS/HYPOTHESIS The therapeutic benefit of physical activity to prevent and treat type 2 diabetes is commonly accepted. However, the impact of the disease on the acute metabolic response is less clear. To this end, we investigated the effect of type 2 diabetes on exercise-induced plasma metabolite changes and the muscular transcriptional response using a complementary metabolomics/transcriptomics approach. METHODS We analysed 139 plasma metabolites and hormones at nine time points, and whole genome expression in skeletal muscle at three time points, during a 60 min bicycle ergometer exercise and a 180 min recovery phase in type 2 diabetic patients and healthy controls matched for age, percentage body fat and maximal oxygen consumption (VO2). RESULTS Pathway analysis of differentially regulated genes upon exercise revealed upregulation of regulators of GLUT4 (SLC2A4RG, FLOT1, EXOC7, RAB13, RABGAP1 and CBLB), glycolysis (HK2, PFKFB1, PFKFB3, PFKM, FBP2 and LDHA) and insulin signal mediators in diabetic participants compared with controls. Notably, diabetic participants had normalised rates of lactate and insulin levels, and of glucose appearance and disappearance, after exercise. They also showed an exercise-induced compensatory regulation of genes involved in biosynthesis and metabolism of amino acids (PSPH, GATM, NOS1 and GLDC), which responded to differences in the amino acid profile (consistently lower plasma levels of glycine, cysteine and arginine). Markers of fat oxidation (acylcarnitines) and lipolysis (glycerol) did not indicate impaired metabolic flexibility during exercise in diabetic participants. CONCLUSIONS/INTERPRETATION Type 2 diabetic individuals showed specific exercise-regulated gene expression. These data provide novel insight into potential mechanisms to ameliorate the disturbed glucose and amino acid metabolism associated with type 2 diabetes.
Collapse
Affiliation(s)
- Jakob S Hansen
- Centre of Inflammation and Metabolism, Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
418
|
Stanford KI, Middelbeek RJW, Goodyear LJ. Exercise Effects on White Adipose Tissue: Beiging and Metabolic Adaptations. Diabetes 2015; 64:2361-8. [PMID: 26050668 PMCID: PMC4477356 DOI: 10.2337/db15-0227] [Citation(s) in RCA: 228] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 03/16/2015] [Indexed: 12/12/2022]
Abstract
Regular physical activity and exercise training have long been known to cause adaptations to white adipose tissue (WAT), including decreases in cell size and lipid content and increases in mitochondrial proteins. In this article, we discuss recent studies that have investigated the effects of exercise training on mitochondrial function, the "beiging" of WAT, regulation of adipokines, metabolic effects of trained adipose tissue on systemic metabolism, and depot-specific responses to exercise training. The major WAT depots in the body are found in the visceral cavity (vWAT) and subcutaneously (scWAT). In rodent models, exercise training increases mitochondrial biogenesis and activity in both these adipose tissue depots. Exercise training also increases expression of the brown adipocyte marker uncoupling protein 1 (UCP1) in both adipose tissue depots, although these effects are much more pronounced in scWAT. Consistent with the increase in UCP1, exercise training increases the presence of brown-like adipocytes in scWAT, also known as browning or beiging. Training results in changes in the gene expression of thousands of scWAT genes and an altered adipokine profile in both scWAT and vWAT. Transplantation of trained scWAT in sedentary recipient mice results in striking improvements in skeletal muscle glucose uptake and whole-body metabolic homeostasis. Human and rodent exercise studies have indicated that exercise training can alter circulating adipokine concentration as well as adipokine expression in adipose tissue. Thus, the profound changes to WAT in response to exercise training may be part of the mechanism by which exercise improves whole-body metabolic health.
Collapse
Affiliation(s)
- Kristin I Stanford
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, MA Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Roeland J W Middelbeek
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, MA Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA
| | - Laurie J Goodyear
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Boston, MA Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| |
Collapse
|
419
|
Betz MJ, Enerbäck S. Human Brown Adipose Tissue: What We Have Learned So Far. Diabetes 2015; 64:2352-60. [PMID: 26050667 DOI: 10.2337/db15-0146] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/26/2015] [Indexed: 11/13/2022]
Abstract
Brown adipose tissue (BAT) is a unique tissue that is able to convert chemical energy directly into heat when activated by the sympathetic nervous system. While initially believed to be of relevance only in human newborns and infants, research during recent years provided unequivocal evidence of active BAT in human adults. Moreover, it has become clear that BAT plays an important role in insulin sensitivity in rodents and humans. This has opened the possibility for exciting new therapies for obesity and diabetes. This review summarizes the current state of research with a special focus on recent advances regarding BAT and insulin resistance in human adults. Additionally, we provide an outlook on possible future therapeutic uses of BAT in the treatment of obesity and diabetes.
Collapse
Affiliation(s)
- Matthias J Betz
- Department of Endocrinology, Diabetes & Metabolism, University Hospital Basel, Basel, Switzerland
| | - Sven Enerbäck
- Department of Medical and Clinical Genetics, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
420
|
Metabolomic Analysis of the Skeletal Muscle of Mice Overexpressing PGC-1α. PLoS One 2015; 10:e0129084. [PMID: 26114427 PMCID: PMC4482640 DOI: 10.1371/journal.pone.0129084] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/05/2015] [Indexed: 01/01/2023] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC-1α) is a coactivator of various nuclear receptors and other transcription factors whose expression increases in the skeletal muscle during exercise. We have previously made transgenic mice overexpressing PGC-1α in the skeletal muscle (PGC-1α-Tg mice). PGC-1α upregulates the expression of genes associated with red fibers, mitochondrial function, fatty acid oxidation, and branched chain amino acid (BCAA) degradation. However, global analyses of the actual metabolic products have not been investigated. In this study, we conducted metabolomic analysis of the skeletal muscle in PGC-1α-Tg mice by capillary electrophoresis with electrospray ionization time-of-flight mass spectrometry. Principal component analysis and hierarchical cluster analysis showed clearly distinguishable changes in the metabolites between PGC-1α-Tg and wild-type control mice. Changes were observed in metabolite levels of various metabolic pathways such as the TCA cycle, pentose phosphate pathway, nucleotide synthesis, purine nucleotide cycle, and amino acid metabolism, including BCAA and β-alanine. Namely, metabolic products of the TCA cycle increased in PGC-1α-Tg mice, with increased levels of citrate (2.3-fold), succinate (2.2-fold), fumarate (2.8-fold), and malate (2.3-fold) observed. Metabolic products associated with the pentose phosphate pathway and nucleotide biosynthesis also increased in PGC-1α-Tg mice. Meanwhile, BCAA levels decreased (Val, 0.7-fold; Leu, 0.8-fold; and Ile, 0.7-fold), and Glu (3.1-fold) and Asp (2.2-fold) levels increased. Levels of β-alanine and related metabolites were markedly decreased in PGC-1α-Tg mice. Coordinated regulation of the TCA cycle and amino acid metabolism, including BCAA, suggests that PGC-1α plays important roles in energy metabolism. Moreover, our metabolomics data showing the activation of the purine nucleotide pathway, malate–aspartate shuttle, as well as creatine metabolism, which are known to be active during exercise, further suggests that PGC-1α regulates metabolism in exercise. Thus, we demonstrated the roles of PGC-1α in the skeletal muscle at the metabolite level.
Collapse
|
421
|
Electric Pulse Stimulation of Myotubes as an In Vitro Exercise Model: Cell-Mediated and Non-Cell-Mediated Effects. Sci Rep 2015; 5:10944. [PMID: 26091097 PMCID: PMC4473537 DOI: 10.1038/srep10944] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/27/2015] [Indexed: 01/05/2023] Open
Abstract
Regular exercise has emerged as one of the best therapeutic strategies to prevent and treat type-2-diabetes. Exercise-induced changes in the muscle secretome, consisting of myokines and metabolites, may underlie the inter-organ communication between muscle and other organs. To investigate this crosstalk, we developed an in vitro system in which mouse C2C12 myotubes underwent electric pulse stimulation (EPS) to induce contraction. Subsequently the effects of EPS-conditioned media (EPS-CM) on hepatocytes were investigated. Here, we demonstrate that EPS-CM induces Metallothionein 1/2 and Slc30a2 gene expression and reduces Cyp2a3 gene expression in rat hepatocytes. When testing EPS-CM that was generated in the absence of C2C12 myotubes (non-cell EPS-CM) no decrease in Cyp2a3 expression was detected. However, similar inductions in hepatic Mt1/2 and Slc30a2 expression were observed. Non-cell EPS-CM were also applied to C2C12 myotubes and compared to C2C12 myotubes that underwent EPS: here changes in AMPK phosphorylation and myokine secretion largely depended on EPS-induced contraction. Taken together, these findings indicate that EPS can alter C2C12 myotube function and thereby affect gene expression in cells subjected to EPS-CM (Cyp2a3). However, EPS can also generate non-cell-mediated changes in cell culture media, which can affect gene expression in cells subjected to EPS-CM too. While EPS clearly represents a valuable tool in exercise research, care should be taken in experimental design to control for non-cell-mediated effects.
Collapse
|
422
|
Correia JC, Ferreira DMS, Ruas JL. Intercellular: local and systemic actions of skeletal muscle PGC-1s. Trends Endocrinol Metab 2015; 26:305-14. [PMID: 25934582 DOI: 10.1016/j.tem.2015.03.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/29/2015] [Accepted: 03/31/2015] [Indexed: 12/16/2022]
Abstract
Physical exercise promotes complex adaptations in skeletal muscle that benefit various aspects of human health. Many of these adaptations are coordinated at the gene expression level by the concerted action of transcriptional regulators. Peroxisome proliferator-activated receptor gamma (PPARγ) coactivator-1 (PGC-1) proteins play a prominent role in skeletal muscle transcriptional reprogramming induced by numerous stimuli. PGC-1s are master coactivators that orchestrate broad gene programs to modulate fuel supply and mitochondrial function, thus improving cellular energy metabolism. Recent studies unveiled novel biological functions for PGC-1s that extend well beyond skeletal muscle bioenergetics. Here we review recent advances in our understanding of PGC-1 actions in skeletal muscle, with special focus on their systemic effects.
Collapse
Affiliation(s)
- Jorge C Correia
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Duarte M S Ferreira
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Jorge L Ruas
- Molecular and Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177 Stockholm, Sweden.
| |
Collapse
|
423
|
Brestoff JR, Artis D. Immune regulation of metabolic homeostasis in health and disease. Cell 2015; 161:146-160. [PMID: 25815992 DOI: 10.1016/j.cell.2015.02.022] [Citation(s) in RCA: 332] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 02/07/2023]
Abstract
Obesity is an increasingly prevalent disease worldwide. While genetic and environmental factors are known to regulate the development of obesity and associated metabolic diseases, emerging studies indicate that innate and adaptive immune cell responses in adipose tissue have critical roles in the regulation of metabolic homeostasis. In the lean state, type 2 cytokine-associated immune cell responses predominate in white adipose tissue and protect against weight gain and insulin resistance through direct effects on adipocytes and elicitation of beige adipose. In obesity, these metabolically beneficial immune pathways become dysregulated, and adipocytes and other factors initiate metabolically deleterious type 1 inflammation that impairs glucose metabolism. This review discusses our current understanding of the functions of different types of adipose tissue and how immune cells regulate adipocyte function and metabolic homeostasis in the context of health and disease and highlights. We also highlight the potential of targeting immuno-metabolic pathways as a therapeutic strategy to treat obesity and associated diseases.
Collapse
Affiliation(s)
- Jonathan R Brestoff
- Jill Roberts Institute for Research in Inflammatory Bowel Disease, Joan and Sanford I. Weill Department of Medicine, Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, New York, NY, 10021, USA; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - David Artis
- Jill Roberts Institute for Research in Inflammatory Bowel Disease, Joan and Sanford I. Weill Department of Medicine, Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, New York, NY, 10021, USA.
| |
Collapse
|
424
|
Affiliation(s)
- Milène Catoire
- Nutrition, Metabolism and Genomics Group, Division of Human NutritionWageningen UniversityWageningenThe Netherlands
| | - Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human NutritionWageningen UniversityWageningenThe Netherlands
| |
Collapse
|
425
|
Shimizu N, Maruyama T, Yoshikawa N, Matsumiya R, Ma Y, Ito N, Tasaka Y, Kuribara-Souta A, Miyata K, Oike Y, Berger S, Schütz G, Takeda S, Tanaka H. A muscle-liver-fat signalling axis is essential for central control of adaptive adipose remodelling. Nat Commun 2015; 6:6693. [PMID: 25827749 PMCID: PMC4396397 DOI: 10.1038/ncomms7693] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 02/19/2015] [Indexed: 12/16/2022] Open
Abstract
Skeletal muscle has a pleiotropic role in organismal energy metabolism, for example, by storing protein as an energy source, or by excreting endocrine hormones. Muscle proteolysis is tightly controlled by the hypothalamus-pituitary-adrenal signalling axis via a glucocorticoid-driven transcriptional programme. Here we unravel the physiological significance of this catabolic process using skeletal muscle-specific glucocorticoid receptor (GR) knockout (GRmKO) mice. These mice have increased muscle mass but smaller adipose tissues. Metabolically, GRmKO mice show a drastic shift of energy utilization and storage in muscle, liver and adipose tissues. We demonstrate that the resulting depletion of plasma alanine serves as a cue to increase plasma levels of fibroblast growth factor 21 (FGF21) and activates liver-fat communication, leading to the activation of lipolytic genes in adipose tissues. We propose that this skeletal muscle-liver-fat signalling axis may serve as a target for the development of therapies against various metabolic diseases, including obesity. Skeletal muscle proteolysis can affect organismal energy homeostasis. Here, the authors provide molecular insight into this process by showing that muscle-derived alanine acts as a signal that triggers FGF21 secretion from the liver, which then regulates lipolysis and browning of white fat tissue.
Collapse
Affiliation(s)
- Noriaki Shimizu
- Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Takako Maruyama
- Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Noritada Yoshikawa
- Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Ryo Matsumiya
- Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Yanxia Ma
- Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Naoki Ito
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-higashi, Kodaira, Tokyo 187-8502, Japan
| | - Yuki Tasaka
- Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Akiko Kuribara-Souta
- Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Keishi Miyata
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Yuichi Oike
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Stefan Berger
- Division of Molecular Biology of the Cell I, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Günther Schütz
- Division of Molecular Biology of the Cell I, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-higashi, Kodaira, Tokyo 187-8502, Japan
| | - Hirotoshi Tanaka
- 1] Department of Rheumatology and Allergy, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan [2] Division of Rheumatology, Center for Antibody and Vaccine, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| |
Collapse
|
426
|
Urinary (1)H-NMR-based metabolic profiling of children with NAFLD undergoing VSL#3 treatment. Int J Obes (Lond) 2015; 39:1118-25. [PMID: 25809828 DOI: 10.1038/ijo.2015.40] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/15/2014] [Accepted: 02/08/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Nowadays, non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases in children. Our recent clinical trial demonstrated that dietary and VSL#3-based interventions may improve fatty liver by ultrasound and body mass index (BMI) after 4 months. OBJECTIVES As in this short-term trial, as in others, it is impracticable to monitor response to therapy or treatment by liver biopsy, we aimed to identify a panel of potential non-invasive metabolic biomarkers by a urinary metabolic profiling. METHODS Urine samples from a group of 31 pediatric NAFLD patients, enrolled in a VSL#3 clinical trial, were analyzed by high-resolution proton nuclear magnetic resonance spectroscopy in combination with analysis of variance-Simultaneous Component Analysis model and multivariate data analyses. Urinary metabolic profiles were interpreted in terms of clinical patient feature, treatment and chronology pattern correlations. RESULTS VSL#3 treatment induced changes in NAFLD urinary metabolic phenotype mainly at level of host amino-acid metabolism (that is, valine, tyrosine, 3-amino-isobutyrate or β-aminoisobutyric acid (BAIBA)), nucleic acid degradation (pseudouridine), creatinine metabolism (methylguanidine) and secondarily at the level of gut microbial amino-acid metabolism (that is, 2-hydroxyisobutyrate from valine degradation). Furthermore, some of these metabolites correlated with clinical primary and secondary trial end points after VSL#3 treatment: tyrosine and the organic acid U4 positively with alanine aminotransferase (R=0.399, P=0.026) and BMI (R=0.36, P=0.045); BAIBA and tyrosine negatively with active glucagon-like-peptide 1 (R=-0.51, P=0.003; R=-0.41, P=0.021, respectively). CONCLUSIONS VSL#3 treatment-dependent urinary metabotypes of NAFLD children may be considered as non-invasive effective biomarkers to evaluate the response to treatment.
Collapse
|
427
|
Abstract
Exercise represents a major challenge to whole-body homeostasis provoking widespread perturbations in numerous cells, tissues, and organs that are caused by or are a response to the increased metabolic activity of contracting skeletal muscles. To meet this challenge, multiple integrated and often redundant responses operate to blunt the homeostatic threats generated by exercise-induced increases in muscle energy and oxygen demand. The application of molecular techniques to exercise biology has provided greater understanding of the multiplicity and complexity of cellular networks involved in exercise responses, and recent discoveries offer perspectives on the mechanisms by which muscle "communicates" with other organs and mediates the beneficial effects of exercise on health and performance.
Collapse
Affiliation(s)
- John A Hawley
- Exercise & Nutrition Research Group, School of Exercise Sciences, Australian Catholic University, Fitzroy, Victoria 3065, Australia; Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Merseyside L3 5UA, UK.
| | - Mark Hargreaves
- Department of Physiology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michael J Joyner
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA
| | - Juleen R Zierath
- Department of Molecular Medicine, Karolinska Institutet, von Eulers väg 4a, 171 77 Stockholm, Sweden; The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
| |
Collapse
|
428
|
Ruiz JR, Martinez-Tellez B, Sanchez-Delgado G, Aguilera CM, Gil A. Regulation of energy balance by brown adipose tissue: at least three potential roles for physical activity. Br J Sports Med 2015; 49:972-3. [PMID: 25807160 DOI: 10.1136/bjsports-2014-094537] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Jonatan R Ruiz
- PROFITH "PROmoting FITness and Health through physical activity" Research Group, Faculty of Sport Sciences, Department of Physical Education and Sport, University of Granada, Granada, Spain
| | - Borja Martinez-Tellez
- PROFITH "PROmoting FITness and Health through physical activity" Research Group, Faculty of Sport Sciences, Department of Physical Education and Sport, University of Granada, Granada, Spain
| | - Guillermo Sanchez-Delgado
- PROFITH "PROmoting FITness and Health through physical activity" Research Group, Faculty of Sport Sciences, Department of Physical Education and Sport, University of Granada, Granada, Spain
| | - Concepcion M Aguilera
- Department of Biochemistry and Molecular Biology II, Institute of Nutrition and Food Technology, Centre for Biomedical Research, University of Granada, Granada, Spain
| | - Angel Gil
- Department of Biochemistry and Molecular Biology II, Institute of Nutrition and Food Technology, Centre for Biomedical Research, University of Granada, Granada, Spain
| |
Collapse
|
429
|
Abstract
Evidence from rodents established an important role of brown adipose tissue (BAT) in energy expenditure. Moreover, to sustain thermogenesis, BAT has been shown to be a powerful sink for draining and oxidation of glucose and triglycerides from blood. The potential of BAT activity in protection against obesity and metabolic syndrome is recognized. Recently, an unexpected presence and activity of BAT has been found in adult humans. Here we review the most recent research in this field and, specifically, how new findings apply to humans. Moreover, we seek to clarify the underlying biological processes occurring beyond the burst of new nomenclature in the field. The cell type responsible for thermogenesis, the brown adipocyte, arises from complex developmental processes. In addition to 'classical' brown adipocytes, present in developmentally programmed BAT depots, there are brown adipocytes, named 'brite' (from 'brown-in-white') or 'beige', which appear in response to thermogenic stimuli in white fat due to the so-called 'browning' process. Beige/brite cells appear to be important components of BAT depots in adult humans. In addition to the known control of BAT activity by the sympathetic nervous system, metabolic and hormonal signals originating in muscle or liver (e.g. irisin, FGF21) are recognized as activators of BAT and beige/brite adipocytes.
Collapse
Affiliation(s)
- Rubén Cereijo
- Departament de Bioquímica i Biologia Molecular, Institute of Biomedicine (IBUB), University of Barcelona, and CIBER Fisiopatología de la Obesidad y Nutrición , Barcelona, Catalonia , Spain
| | | | | |
Collapse
|
430
|
Abstract
Skeletal and cardiac muscles play key roles in the regulation of systemic energy homeostasis and display remarkable plasticity in their metabolic responses to caloric availability and physical activity. In this Perspective we discuss recent studies highlighting transcriptional mechanisms that govern systemic metabolism by striated muscles. We focus on the participation of the Mediator complex in this process, and suggest that tissue-specific regulation of Mediator subunits impacts metabolic homeostasis.
Collapse
Affiliation(s)
- Kedryn K Baskin
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Benjamin R Winders
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA; Cardiology Division, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA.
| |
Collapse
|
431
|
Sidossis L, Kajimura S. Brown and beige fat in humans: thermogenic adipocytes that control energy and glucose homeostasis. J Clin Invest 2015; 125:478-86. [PMID: 25642708 DOI: 10.1172/jci78362] [Citation(s) in RCA: 487] [Impact Index Per Article: 54.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Brown adipose tissue (BAT), a specialized fat that dissipates energy to produce heat, plays an important role in the regulation of energy balance. Two types of thermogenic adipocytes with distinct developmental and anatomical features exist in rodents and humans: classical brown adipocytes and beige (also referred to as brite) adipocytes. While classical brown adipocytes are located mainly in dedicated BAT depots of rodents and infants, beige adipocytes sporadically reside with white adipocytes and emerge in response to certain environmental cues, such as chronic cold exposure, a process often referred to as "browning" of white adipose tissue. Recent studies indicate the existence of beige adipocytes in adult humans, making this cell type an attractive therapeutic target for obesity and obesity-related diseases, including type 2 diabetes. This Review aims to cover recent progress in our understanding of the anatomical, developmental, and functional characteristics of brown and beige adipocytes and discuss emerging questions, with a special emphasis on adult human BAT.
Collapse
|
432
|
Roberts LD, Ashmore T, Kotwica AO, Murfitt SA, Fernandez BO, Feelisch M, Murray AJ, Griffin JL. Inorganic nitrate promotes the browning of white adipose tissue through the nitrate-nitrite-nitric oxide pathway. Diabetes 2015; 64:471-484. [PMID: 25249574 PMCID: PMC4351918 DOI: 10.2337/db14-0496] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Inorganic nitrate was once considered an oxidation end product of nitric oxide metabolism with little biological activity. However, recent studies have demonstrated that dietary nitrate can modulate mitochondrial function in man and is effective in reversing features of the metabolic syndrome in mice. Using a combined histological, metabolomics, and transcriptional and protein analysis approach, we mechanistically defined that nitrate not only increases the expression of thermogenic genes in brown adipose tissue but also induces the expression of brown adipocyte-specific genes and proteins in white adipose tissue, substantially increasing oxygen consumption and fatty acid β-oxidation in adipocytes. Nitrate induces these phenotypic changes through a mechanism distinct from known physiological small molecule activators of browning, the recently identified nitrate-nitrite-nitric oxide pathway. The nitrate-induced browning effect was enhanced in hypoxia, a serious comorbidity affecting white adipose tissue in obese individuals, and corrected impaired brown adipocyte-specific gene expression in white adipose tissue in a murine model of obesity. Because resulting beige/brite cells exhibit antiobesity and antidiabetic effects, nitrate may be an effective means of inducing the browning response in adipose tissue to treat the metabolic syndrome.
Collapse
MESH Headings
- Adipocytes, Brown/physiology
- Adipocytes, White/drug effects
- Adipocytes, White/physiology
- Adipose Tissue, Brown
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Animals
- Cells, Cultured
- Cyclic GMP
- Cyclic GMP-Dependent Protein Kinases
- Dose-Response Relationship, Drug
- Male
- Mice
- Mice, Inbred C57BL
- Nitrates/metabolism
- Nitrates/pharmacology
- Nitric Oxide/metabolism
- Nitrites/metabolism
- Rats
- Rats, Wistar
Collapse
Affiliation(s)
- Lee D Roberts
- Medical Research Council – Human Nutrition Research, Elsie Widdowson Laboratory, 120 Fulbourn Road, Cambridge, CB2 9NL, UK
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, 80 Tennis Court Road, Old Addenbrooke’s Site, Cambridge, CB2 1GA, UK
| | - Tom Ashmore
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, 80 Tennis Court Road, Old Addenbrooke’s Site, Cambridge, CB2 1GA, UK
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Aleksandra O Kotwica
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Steven A Murfitt
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, 80 Tennis Court Road, Old Addenbrooke’s Site, Cambridge, CB2 1GA, UK
| | - Bernadette O Fernandez
- Faculty of Medicine, Clinical & Experimental Sciences, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Martin Feelisch
- Faculty of Medicine, Clinical & Experimental Sciences, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Julian L Griffin
- Medical Research Council – Human Nutrition Research, Elsie Widdowson Laboratory, 120 Fulbourn Road, Cambridge, CB2 9NL, UK
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, 80 Tennis Court Road, Old Addenbrooke’s Site, Cambridge, CB2 1GA, UK
| |
Collapse
|
433
|
Ip BC, Liu C, Lichtenstein AH, von Lintig J, Wang XD. Lycopene and apo-10'-lycopenoic acid have differential mechanisms of protection against hepatic steatosis in β-carotene-9',10'-oxygenase knockout male mice. J Nutr 2015; 145:268-76. [PMID: 25644347 PMCID: PMC4304024 DOI: 10.3945/jn.114.200238] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Nonalcoholic fatty liver disease is positively associated with obesity and cardiovascular disease risk. Apo-10'-lycopenoic acid (APO10LA), a potential oxidation product of apo-10'-lycopenal that is generated endogenously by β-carotene-9',10'-oxygenase (BCO2) cleavage of lycopene, inhibited hepatic steatosis in BCO2-expressing mice. OBJECTIVE The present study evaluated lycopene and APO10LA effects on hepatic steatosis in mice without BCO2 expression. METHODS Male and female BCO2-knockout (BCO2-KO) mice were fed a high saturated fat diet (HSFD) with or without APO10LA (10 mg/kg diet) or lycopene (100 mg/kg diet) for 12 wk. RESULTS Lycopene or APO10LA supplementation reduced hepatic steatosis incidence (78% and 72%, respectively) and severity in BCO2-KO male mice. Female mice did not develop steatosis, had greater hepatic total cholesterol (3.06 vs. 2.31 mg/g tissue) and cholesteryl ester (1.58 vs. 0.86 mg/g tissue), but had lower plasma triglyceride (TG) (229 vs. 282 mg/dL) and cholesterol (97.1 vs. 119 mg/dL) than male mice. APO10LA-mitigated steatosis in males was associated with reduced hepatic total cholesterol (18%) and activated sirtuin 1 signaling, which resulted in reduced fatty acids (FAs) and TG synthesis markers [stearoyl-coenzyme A (CoA) desaturase protein, 71%; acetyl-CoA carboxylase phosphorylation, 79%; AMP-activated protein kinase phosphorylation, 67%], and elevated cholesterol efflux genes (cytochrome P450 family 7A1, 65%; ATP-binding cassette transporter G5/8, 11%). These APO10LA-mediated effects were not mimicked by lycopene supplementation. Intriguingly, steatosis inhibition by lycopene induced peroxisome proliferator-activated receptor (PPAR)α- and PPARγ-related genes in mesenteric adipose tissue (MAT) that increases mitochondrial uncoupling [cell death-inducing DNA fragmentation factor, α subunit-like effector a, 55%; PR domain-containing 16, 47%; uncoupling protein 3 (Ucp3), 55%], FA β-oxidation (PPARα, 53%; very long chain acyl-CoA dehydrogenase, 38%), and uptake (FA transport protein 4, 29%; lipoprotein lipase 43%). Expressions of 10 MAT PPAR-related genes were inversely correlated with steatosis score, suggesting that lycopene reduced steatosis by increasing MAT FA utilization. CONCLUSIONS Our data suggest that lycopene and APO10LA inhibit HSFD-induced steatosis in BCO2-KO male mice through differential mechanisms. Sex disparity of BCO2-KO mice was observed in the outcomes of HSFD-induced liver steatosis and plasma lipids.
Collapse
Affiliation(s)
- Blanche C Ip
- Nutrition and Cancer Biology Laboratory,,Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA; and
| | - Chun Liu
- Nutrition and Cancer Biology Laboratory
| | - Alice H Lichtenstein
- Cardiovascular Nutrition Laboratory, Jean-Mayer USDA Human Nutrition Research Center on Aging, and,Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA; and
| | - Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Xiang-Dong Wang
- Nutrition and Cancer Biology Laboratory, Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA; and
| |
Collapse
|
434
|
Metabolomics in the developmental origins of obesity and its cardiometabolic consequences. J Dev Orig Health Dis 2015; 6:65-78. [PMID: 25631626 DOI: 10.1017/s204017441500001x] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this review, we discuss the potential role of metabolomics to enhance understanding of obesity-related developmental origins of health and disease (DOHaD). We first provide an overview of common techniques and analytical approaches to help interested investigators dive into this relatively novel field. Next, we describe how metabolomics may capture exposures that are notoriously difficult to quantify, and help to further refine phenotypes associated with excess adiposity and related metabolic sequelae over the life course. Together, these data can ultimately help to elucidate mechanisms that underlie fetal metabolic programming. Finally, we review current gaps in knowledge and identify areas where the field of metabolomics is likely to provide insights into mechanisms linked to DOHaD in human populations.
Collapse
|
435
|
Inhibiting peripheral serotonin synthesis reduces obesity and metabolic dysfunction by promoting brown adipose tissue thermogenesis. Nat Med 2014; 21:166-72. [PMID: 25485911 DOI: 10.1038/nm.3766] [Citation(s) in RCA: 329] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/05/2014] [Indexed: 12/23/2022]
Abstract
Mitochondrial uncoupling protein 1 (UCP1) is enriched within interscapular brown adipose tissue (iBAT) and beige (also known as brite) adipose tissue, but its thermogenic potential is reduced with obesity and type 2 diabetes for reasons that are not understood. Serotonin (5-hydroxytryptamine, 5-HT) is a highly conserved biogenic amine that resides in non-neuronal and neuronal tissues that are specifically regulated via tryptophan hydroxylase 1 (Tph1) and Tph2, respectively. Recent findings suggest that increased peripheral serotonin and polymorphisms in TPH1 are associated with obesity; however, whether this is directly related to reduced BAT thermogenesis and obesity is not known. We find that Tph1-deficient mice fed a high-fat diet (HFD) are protected from obesity, insulin resistance and nonalcoholic fatty liver disease (NAFLD) while exhibiting greater energy expenditure by BAT. Small-molecule chemical inhibition of Tph1 in HFD-fed mice mimics the benefits ascribed to Tph1 genetic deletion, effects that depend on UCP1-mediated thermogenesis. The inhibitory effects of serotonin on energy expenditure are cell autonomous, as serotonin blunts β-adrenergic induction of the thermogenic program in brown and beige adipocytes in vitro. As obesity increases peripheral serotonin, the inhibition of serotonin signaling or its synthesis in adipose tissue may be an effective treatment for obesity and its comorbidities.
Collapse
|
436
|
Robinson MM, Soop M, Sohn TS, Morse DM, Schimke JM, Klaus KA, Nair KS. High insulin combined with essential amino acids stimulates skeletal muscle mitochondrial protein synthesis while decreasing insulin sensitivity in healthy humans. J Clin Endocrinol Metab 2014; 99:E2574-83. [PMID: 25222757 PMCID: PMC4255106 DOI: 10.1210/jc.2014-2736] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
CONTEXT Insulin and essential amino acids (EAAs) regulate skeletal muscle protein synthesis, yet their independent effects on mitochondrial protein synthesis (MiPS) and oxidative function remain to be clearly defined. OBJECTIVE The purpose of this study was to determine the effects of high or low insulin with or without EAAs on MiPS. DESIGN Thirty participants were randomized to 3 groups of 10 each with each participant studied twice. Study groups comprised (1) low and high insulin, (2) low insulin with and without EAAs, and (3) high insulin with and without EAAs. SETTING The study was conducted in an in-patient clinical research unit. PARTICIPANTS Eligible participants were 18 to 45 years old, had a body mass index of <25 kg/m(2), and were free of diseases and medications that might impair mitochondrial function. INTERVENTION Low (∼ 6 μU/mL) and high (∼ 40 μU/mL) insulin levels were maintained by iv insulin infusion during a somatostatin clamp while maintaining euglycemia (4.7-5.2 mM) and replacing GH and glucagon. The EAA infusion was 5.4% NephrAmine. l-[ring-(13)C6]Phenylalanine was infused, and muscle needle biopsies were performed. MAIN OUTCOMES Muscle MiPS, oxidative enzymes, and plasma amino acid metabolites were measured. RESULTS MiPS and oxidative enzyme activities did not differ between low and high insulin (MiPS: 0.07 ± 0.009 vs 0.07 ± 0.006%/h, P = .86) or between EAAs and saline during low insulin (MiPS: 0.05 ± 0.01 vs 0.07 ± 0.01, P = .5). During high insulin, EAAs in comparison with saline increased MiPS (0.1 ± 0.01 vs 0.06 ± 0.01, P < .05) and cytochrome c oxidase activity (P < .05) but not citrate synthase (P = .27). EAA infusion decreased (P < .05) the glucose infusion rates needed to maintain euglycemia during low (∼ 40%) and high insulin (∼ 24%). CONCLUSION EAAs increased MiPS and oxidative enzyme activity only with high insulin concentrations.
Collapse
|
437
|
Rodionov RN, Jarzebska N, Weiss N, Lentz SR. AGXT2: a promiscuous aminotransferase. Trends Pharmacol Sci 2014; 35:575-82. [PMID: 25294000 DOI: 10.1016/j.tips.2014.09.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 12/11/2022]
Abstract
Alanine-glyoxylate aminotransferase 2 (AGXT2) is a multifunctional mitochondrial aminotransferase that was first identified in 1978. The physiological importance of AGXT2 was largely overlooked for three decades because AGXT2 is less active in glyoxylate metabolism than AGXT1, the enzyme that is deficient in primary hyperoxaluria type I. Recently, several novel functions of AGXT2 have been 'rediscovered' in the setting of modern genomic and metabolomic studies. It is now apparent that AGXT2 has multiple substrates and products and that altered AGXT2 activity may contribute to the pathogenesis of cardiovascular, renal, neurological, and hematological diseases. This article reviews the biochemical properties and physiological functions of AGXT2, its unique role at the intersection of key mitochondrial pathways, and its potential as a drug target.
Collapse
Affiliation(s)
- Roman N Rodionov
- University Center for Vascular Medicine and Department of Internal Medicine, Division of Angiology, University Hospital 'Carl Gustav Carus', Technische Universität Dresden, Fetscherstrasse 42, 01307 Dresden, Germany
| | - Natalia Jarzebska
- University Hospital 'Carl Gustav Carus', Technische Universität Dresden, Fetscherstrasse 42, 01307 Dresden, Germany
| | - Norbert Weiss
- University Center for Vascular Medicine and Department of Internal Medicine, Division of Angiology, University Hospital 'Carl Gustav Carus', Technische Universität Dresden, Fetscherstrasse 42, 01307 Dresden, Germany
| | - Steven R Lentz
- Department of Internal Medicine, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA.
| |
Collapse
|
438
|
Li Y, Fromme T, Schweizer S, Schöttl T, Klingenspor M. Taking control over intracellular fatty acid levels is essential for the analysis of thermogenic function in cultured primary brown and brite/beige adipocytes. EMBO Rep 2014; 15:1069-76. [PMID: 25135951 DOI: 10.15252/embr.201438775] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Thermogenesis in brown adipocytes, conferred by mitochondrial uncoupling protein 1 (UCP1), is receiving great attention because metabolically active brown adipose tissue may protect humans from metabolic diseases. In particular, the thermogenic function of brown-like adipocytes in white adipose tissue, known as brite (or beige) adipocytes, is currently of prime interest. A valid procedure to quantify the specific contribution of UCP1 to thermogenesis is thus of vital importance. Adrenergic stimulation of lipolysis is a common way to activate UCP1. We here report, however, that in this frequently applied setup, taking control over intracellular fatty acid levels is essential for the analysis of thermogenic function in cultured brown and brite adipocytes. By the application of these findings, we demonstrate that UCP1 is functionally thermogenic in intact brite adipocytes and adrenergic UCP1 activation is largely dependent on adipose triglyceride lipase (ATGL) rather than hormone sensitive lipase (HSL).
Collapse
Affiliation(s)
- Yongguo Li
- Molecular Nutritional Medicine, Else Kröner Fresenius Center for Nutritional Medicine, Technische Universität München, Freising, Germany
| | - Tobias Fromme
- Molecular Nutritional Medicine, Else Kröner Fresenius Center for Nutritional Medicine, Technische Universität München, Freising, Germany
| | - Sabine Schweizer
- Molecular Nutritional Medicine, Else Kröner Fresenius Center for Nutritional Medicine, Technische Universität München, Freising, Germany
| | - Theresa Schöttl
- Molecular Nutritional Medicine, Else Kröner Fresenius Center for Nutritional Medicine, Technische Universität München, Freising, Germany
| | - Martin Klingenspor
- Molecular Nutritional Medicine, Else Kröner Fresenius Center for Nutritional Medicine, Technische Universität München, Freising, Germany
| |
Collapse
|
439
|
Effect of exercise intensity on isoform-specific expressions of NT-PGC-1 α mRNA in mouse skeletal muscle. BIOMED RESEARCH INTERNATIONAL 2014; 2014:402175. [PMID: 25136584 PMCID: PMC4106048 DOI: 10.1155/2014/402175] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/02/2014] [Accepted: 04/28/2014] [Indexed: 11/17/2022]
Abstract
PGC-1α is an inducible transcriptional coactivator that regulates mitochondrial biogenesis and cellular energy metabolism in skeletal muscle. Recent studies have identified two additional PGC-1α transcripts that are derived from an alternative exon 1 (exon 1b) and induced by exercise. Given that the PGC-1α gene also produces NT-PGC-1α transcript by alternative 3′ splicing between exon 6 and exon 7, we have investigated isoform-specific expression of NT-PGC-1α mRNA in mouse skeletal muscle during physical exercise with different intensities. We report here that NT-PGC-1α-a mRNA expression derived from a canonical exon 1 (exon 1a) is increased by high-intensity exercise and AMPK activator AICAR in mouse skeletal muscle but not altered by low- and medium-intensity exercise and β2-adrenergic receptor agonist clenbuterol. In contrast, the alternative exon 1b-driven NT-PGC-1α-b (PGC-1α4) and NT-PGC-1α-c are highly induced by low-, medium-, and high-intensity exercise, AICAR, and clenbuterol. Ectopic expression of NT-PGC-1α-a in C2C12 myotube cells upregulates myosin heavy chain (MHC I, MHC II a) and Glut4, which represent oxidative fibers, and promotes the expression of mitochondrial genes (Cyc1, COX5B, and ATP5B). In line with gene expression data, citrate synthase activity was significantly increased by NT-PGC-1α-a in C2C12 myotube cells. Our results indicate the regulatory role for NT-PGC-1α-a in mitochondrial biogenesis and adaptation of skeletal muscle to endurance exercise.
Collapse
|
440
|
Liu S, Alexander RK, Lee CH. Lipid metabolites as metabolic messengers in inter-organ communication. Trends Endocrinol Metab 2014; 25:356-63. [PMID: 24895003 PMCID: PMC4077945 DOI: 10.1016/j.tem.2014.05.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 04/30/2014] [Accepted: 05/07/2014] [Indexed: 01/08/2023]
Abstract
Metabolic homeostasis is achieved through coordinated regulation across several tissues. Studies using mouse genetic models have shown that perturbation of specific pathways of lipid metabolism in metabolically active tissues impacts systemic metabolic homeostasis. The use of metabolomic technologies combined with genetic models has helped to identify several potential lipid mediators that serve as metabolic messengers to communicate energy status and modulate substrate utilization among tissues. When provided exogenously, these lipid metabolites exhibit biological effects on glucose and lipid metabolism, indicating a therapeutic potential for treating metabolic diseases. In this review we summarize recent advances in inter-organ communication through novel mechanisms, with a focus on lipid mediators synthesized de novo or derived from dietary sources, and discuss challenges and future directions.
Collapse
Affiliation(s)
- Sihao Liu
- Department of Genetics and Complex Diseases, Division of Biological Sciences, Harvard School of Public Health, Boston, MA 02115, USA
| | - Ryan K Alexander
- Department of Genetics and Complex Diseases, Division of Biological Sciences, Harvard School of Public Health, Boston, MA 02115, USA
| | - Chih-Hao Lee
- Department of Genetics and Complex Diseases, Division of Biological Sciences, Harvard School of Public Health, Boston, MA 02115, USA.
| |
Collapse
|
441
|
Winchester L, Veeranki S, Givvimani S, Tyagi SC. Exercise mitigates the adverse effects of hyperhomocysteinemia on macrophages, MMP-9, skeletal muscle, and white adipocytes. Can J Physiol Pharmacol 2014; 92:575-82. [PMID: 24923386 DOI: 10.1139/cjpp-2014-0059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Regular exercise is a great medicine with its benefits encompassing everything from prevention of cardiovascular risk to alleviation of different muscular myopathies. Interestingly, elevated levels of homocysteine (Hcy), also known as hyperhomocysteinemia (HHcy), antagonizes beta-2 adrenergic receptors (β2AR), gamma amino butyric acid (GABA), and peroxisome proliferator-activated receptor-gamma (PPARγ) receptors. HHcy also stimulates an elevation of the M1/M2 macrophage ratio, resulting in a more inflammatory profile. In this review we discuss several potential targets altered by HHcy that result in myopathy and excessive fat accumulation. Several of these HHcy mediated changes can be countered by exercise and culminate into mitigation of HHcy induced myopathy and metabolic syndrome. We suggest that exercise directly impacts levels of Hcy, matrix metalloproteinase 9 (MMP-9), macrophages, and G-protein coupled receptors (GPCRs, especially Gs). While HHcy promotes the M1 macrophage phenotype, it appears that exercise may diminish the M1/M2 ratio, resulting in a less inflammatory phenotype. HHcy through its influence on GPCRs, specifically β₂AR, PPARγ and GABA receptors, promotes accumulation of white fat, whereas exercise enhances the browning of white fat and counters HHcy-mediated effects on GPCRs. Alleviation of HHcy-associated pathologies with exercise also includes reversal of excessive MMP-9 activation. Moreover, exercise, by reducing plasma Hcy levels, may prevent skeletal muscle myopathy, improve exercise capacity and rescue the obese phenotype. The purpose of this review is to summarize the pathological conditions surrounding HHcy and to clarify the importance of regular exercise as a method of disease prevention.
Collapse
Affiliation(s)
- Lee Winchester
- Department of Physiology & Biophysics, University of Louisville, Louisville, KY 40202, USA
| | | | | | | |
Collapse
|
442
|
|
443
|
Baskin KK, Bookout AL, Olson EN. The heart-liver metabolic axis: defective communication exacerbates disease. EMBO Mol Med 2014; 6:436-8. [PMID: 24623378 PMCID: PMC3992070 DOI: 10.1002/emmm.201303800] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The heart has been recognized as an endocrine organ for over 30 years (de Bold, 2011); however, little is known about how the heart communicates with other organs in the body, and even less is known about this process in the diseased heart. In this issue of EMBO Molecular Medicine, Magida and Leinwand (2014) introduce the concept that a primary genetic defect in the heart results in aberrant hepatic lipid metabolism, which consequently exacerbates hypertrophic cardiomyopathy (HCM). This study provides evidence in support of the hypothesis that crosstalk occurs between the heart and liver, and that this becomes disrupted in the diseased state.
Collapse
Affiliation(s)
- Kedryn K Baskin
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | | |
Collapse
|
444
|
Get that myokine burn. Nat Chem Biol 2014. [DOI: 10.1038/nchembio.1466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
445
|
Abstract
The contracting muscle has been shown to act as an endocrine organ, secreting "myokines" that participate in tissue crosstalk. In this issue of Cell Metabolism, Roberts et al. (2014) identify BAIBA as a contraction-induced myokine that results in browning of white adipose tissue and increases fat oxidation in the liver.
Collapse
Affiliation(s)
- Helene L Kammoun
- Cellular and Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne 3004, Victoria, Australia
| | - Mark A Febbraio
- Cellular and Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne 3004, Victoria, Australia.
| |
Collapse
|
446
|
How exercise benefits the body. Nature 2014. [DOI: 10.1038/505265a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|