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Kitzman DW, Lewis GD, Pandey A, Borlaug BA, Sauer AJ, Litwin SE, Sharma K, Jorkasky DK, Khan S, Shah SJ. A novel controlled metabolic accelerator for the treatment of obesity-related heart failure with preserved ejection fraction: Rationale and design of the Phase 2a HuMAIN trial. Eur J Heart Fail 2024. [PMID: 38924328 DOI: 10.1002/ejhf.3305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/18/2024] [Accepted: 05/09/2024] [Indexed: 06/28/2024] Open
Abstract
AIMS Compared with those without obesity, patients with obesity-related heart failure with preserved ejection fraction (HFpEF) have worse symptoms, haemodynamics, and outcomes. Current weight loss strategies (diet, drug, and surgical) work through decreased energy intake rather than increased expenditure and cause significant loss of skeletal muscle mass in addition to adipose tissue. This may have adverse implications for patients with HFpEF, who already have reduced skeletal muscle mass and function and high rates of physical frailty. Mitochondrial uncoupling agents may have unique beneficial effects by producing weight loss via increased catabolism rather than reduced caloric intake, thereby causing loss of adipose tissue while sparing skeletal muscle. HU6 is a controlled metabolic accelerator that is metabolized to the mitochondrial uncoupling agent 2,4-dinotrophenol. HU6 selectively increases carbon oxidation from fat and glucose while also decreasing toxic reactive oxygen species (ROS) production. In addition to sparing skeletal muscle loss, HU6 may have other benefits relevant to obesity-related HFpEF, including reduced specific tissue depots contributing to HFpEF; improved glucose utilization; and reduction in systemic inflammation via both decreased ROS production from mitochondria and decreased cytokine elaboration from excess, dysfunctional adipose. METHODS We describe the rationale and design of HuMAIN-HFpEF, a Phase 2a randomized, double-blind, placebo-controlled, dose-titration, parallel-group trial in patients with obesity-related HFpEF to evaluate the effects of HU6 on weight loss, body composition, exercise capacity, cardiac structure and function, metabolism, and inflammation, and identify optimal dosage for future Phase 3 trials. CONCLUSIONS HuMAIN will test a promising novel agent for obesity-related HFpEF.
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Affiliation(s)
- Dalane W Kitzman
- Section on Geriatrics and Gerontology, Department of Cardiovascular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Gregory D Lewis
- Department of Medicine, Massachusetts General Brigham, Boston, MA, USA
| | - Ambarish Pandey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Barry A Borlaug
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Andrew J Sauer
- Department of Cardiology, Saint Luke's Mid America Heart Institute, Kansas City, MO, USA
| | - Sheldon E Litwin
- Division of Cardiology, Medical University of South Carolina, Charleston, SC, USA
- Division of Cardiology, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA
| | - Kavita Sharma
- Division of Cardiology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | | | | | - Sanjiv J Shah
- Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Ghesmati Z, Rashid M, Fayezi S, Gieseler F, Alizadeh E, Darabi M. An update on the secretory functions of brown, white, and beige adipose tissue: Towards therapeutic applications. Rev Endocr Metab Disord 2024; 25:279-308. [PMID: 38051471 PMCID: PMC10942928 DOI: 10.1007/s11154-023-09850-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/30/2023] [Indexed: 12/07/2023]
Abstract
Adipose tissue, including white adipose tissue (WAT), brown adipose tissue (BAT), and beige adipose tissue, is vital in modulating whole-body energy metabolism. While WAT primarily stores energy, BAT dissipates energy as heat for thermoregulation. Beige adipose tissue is a hybrid form of adipose tissue that shares characteristics with WAT and BAT. Dysregulation of adipose tissue metabolism is linked to various disorders, including obesity, type 2 diabetes, cardiovascular diseases, cancer, and infertility. Both brown and beige adipocytes secrete multiple molecules, such as batokines, packaged in extracellular vesicles or as soluble signaling molecules that play autocrine, paracrine, and endocrine roles. A greater understanding of the adipocyte secretome is essential for identifying novel molecular targets in treating metabolic disorders. Additionally, microRNAs show crucial roles in regulating adipose tissue differentiation and function, highlighting their potential as biomarkers for metabolic disorders. The browning of WAT has emerged as a promising therapeutic approach in treating obesity and associated metabolic disorders. Many browning agents have been identified, and nanotechnology-based drug delivery systems have been developed to enhance their efficacy. This review scrutinizes the characteristics of and differences between white, brown, and beige adipose tissues, the molecular mechanisms involved in the development of the adipocytes, the significant roles of batokines, and regulatory microRNAs active in different adipose tissues. Finally, the potential of WAT browning in treating obesity and atherosclerosis, the relationship of BAT with cancer and fertility disorders, and the crosstalk between adipose tissue with circadian system and circadian disorders are also investigated.
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Affiliation(s)
- Zeinab Ghesmati
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohsen Rashid
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Shabnam Fayezi
- Department of Gynecologic Endocrinology and Fertility Disorders, Women's Hospital, Ruprecht-Karls University of Heidelberg, Heidelberg, Germany
| | - Frank Gieseler
- Division of Experimental Oncology, Department of Hematology and Oncology, University Medical Center Schleswig-Holstein, Campus Lübeck, 23538, Lübeck, Germany
| | - Effat Alizadeh
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Masoud Darabi
- Division of Experimental Oncology, Department of Hematology and Oncology, University Medical Center Schleswig-Holstein, Campus Lübeck, 23538, Lübeck, Germany.
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3
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Dakic T, Velickovic K, Lakic I, Ruzicic A, Milicevic A, Plackic N, Vujovic P, Jevdjovic T. Rat brown adipose tissue thermogenic markers are modulated by estrous cycle phases and short-term fasting. Biofactors 2024; 50:101-113. [PMID: 37482913 DOI: 10.1002/biof.1993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 07/06/2023] [Indexed: 07/25/2023]
Abstract
Brown adipose tissue (BAT) converts chemical energy into heat to maintain body temperature. Although fatty acids (FAs) represent a primary substrate for uncoupling protein 1 (UCP1)-dependent thermogenesis, BAT also utilizes glucose for the same purpose. Considering that estrous cycle effects on BAT are not greatly explored, we examined those of 6-h fasting on interscapular BAT (iBAT) thermogenic markers in proestrus and diestrus. We found that the percentage of multilocular adipocytes was lower in proestrus than in diestrus, although it was increased after fasting in both analyzed estrous cycle stages. Furthermore, the percentage of paucilocular adipocytes was increased by fasting, unlike the percentage of unilocular cells, which decreased in both analyzed stages of the estrous cycle. The UCP1 amount was lower in proestrus irrespectively of the examined dietary regimens. Regarding FA transporters, it was shown that iBAT CD36 content was increased in fasted rats in diestrus. In contrast to GLUT1, the level of GLUT4 was interactively modulated by selected estrous cycle phases and fasting. There was no change in insulin receptor and ERK1/2 activation, while AKT activation was interactively modulated by fasting and estrous cycle stages. Our study showed that iBAT exhibits morphological and functional changes in proestrus and diestrus. Moreover, iBAT undergoes additional dynamic functional and morphological changes during short-term fasting to modulate nutrient utilization and adjust energy expenditure.
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Affiliation(s)
- Tamara Dakic
- Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, University of Belgrade-Faculty for Biology, Belgrade, Serbia
| | - Ksenija Velickovic
- Department of Cell and Tissue Biology, Institute for Zoology, University of Belgrade-Faculty of Biology, Belgrade, Serbia
| | - Iva Lakic
- Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, University of Belgrade-Faculty for Biology, Belgrade, Serbia
| | - Aleksandra Ruzicic
- Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, University of Belgrade-Faculty for Biology, Belgrade, Serbia
| | - Andjela Milicevic
- Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, University of Belgrade-Faculty for Biology, Belgrade, Serbia
| | - Nikola Plackic
- Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, University of Belgrade-Faculty for Biology, Belgrade, Serbia
| | - Predrag Vujovic
- Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, University of Belgrade-Faculty for Biology, Belgrade, Serbia
| | - Tanja Jevdjovic
- Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, University of Belgrade-Faculty for Biology, Belgrade, Serbia
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4
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Aboouf MA, Gorr TA, Hamdy NM, Gassmann M, Thiersch M. Myoglobin in Brown Adipose Tissue: A Multifaceted Player in Thermogenesis. Cells 2023; 12:2240. [PMID: 37759463 PMCID: PMC10526770 DOI: 10.3390/cells12182240] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/01/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Brown adipose tissue (BAT) plays an important role in energy homeostasis by generating heat from chemical energy via uncoupled oxidative phosphorylation. Besides its high mitochondrial content and its exclusive expression of the uncoupling protein 1, another key feature of BAT is the high expression of myoglobin (MB), a heme-containing protein that typically binds oxygen, thereby facilitating the diffusion of the gas from cell membranes to mitochondria of muscle cells. In addition, MB also modulates nitric oxide (NO•) pools and can bind C16 and C18 fatty acids, which indicates a role in lipid metabolism. Recent studies in humans and mice implicated MB present in BAT in the regulation of lipid droplet morphology and fatty acid shuttling and composition, as well as mitochondrial oxidative metabolism. These functions suggest that MB plays an essential role in BAT energy metabolism and thermogenesis. In this review, we will discuss in detail the possible physiological roles played by MB in BAT thermogenesis along with the potential underlying molecular mechanisms and focus on the question of how BAT-MB expression is regulated and, in turn, how this globin regulates mitochondrial, lipid, and NO• metabolism. Finally, we present potential MB-mediated approaches to augment energy metabolism, which ultimately could help tackle different metabolic disorders.
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Affiliation(s)
- Mostafa A. Aboouf
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
| | - Thomas A. Gorr
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
| | - Nadia M. Hamdy
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
| | - Max Gassmann
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Markus Thiersch
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
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5
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Kreiter J, Škulj S, Brkljača Z, Bardakji S, Vazdar M, Pohl EE. FA Sliding as the Mechanism for the ANT1-Mediated Fatty Acid Anion Transport in Lipid Bilayers. Int J Mol Sci 2023; 24:13701. [PMID: 37762012 PMCID: PMC10531397 DOI: 10.3390/ijms241813701] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/27/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Mitochondrial adenine nucleotide translocase (ANT) exchanges ADP for ATP to maintain energy production in the cell. Its protonophoric function in the presence of long-chain fatty acids (FA) is also recognized. Our previous results imply that proton/FA transport can be best described with the FA cycling model, in which protonated FA transports the proton to the mitochondrial matrix. The mechanism by which ANT1 transports FA anions back to the intermembrane space remains unclear. Using a combined approach involving measurements of the current through the planar lipid bilayers reconstituted with ANT1, site-directed mutagenesis and molecular dynamics simulations, we show that the FA anion is first attracted by positively charged arginines or lysines on the matrix side of ANT1 before moving along the positively charged protein-lipid interface and binding to R79, where it is protonated. We show that R79 is also critical for the competitive binding of ANT1 substrates (ADP and ATP) and inhibitors (carboxyatractyloside and bongkrekic acid). The binding sites are well conserved in mitochondrial SLC25 members, suggesting a general mechanism for transporting FA anions across the inner mitochondrial membrane.
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Affiliation(s)
- Jürgen Kreiter
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
| | - Sanja Škulj
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, 10000 Zagreb, Croatia;
| | - Sarah Bardakji
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
| | - Mario Vazdar
- Department of Mathematics, Informatics, and Cybernetics, University of Chemistry and Technology, 166 28 Prague, Czech Republic
| | - Elena E. Pohl
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
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Andrzejczak A, Witkowicz A, Kujawa D, Skrypnik D, Szulińska M, Bogdański P, Łaczmański Ł, Karabon L. NGS Sequencing Reveals New UCP1 Gene Variants Potentially Associated with MetS and/or T2DM Risk in the Polish Population—A Preliminary Study. Genes (Basel) 2023; 14:genes14040789. [PMID: 37107547 PMCID: PMC10137642 DOI: 10.3390/genes14040789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/16/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
The number of people suffering from metabolic syndrome (MetS) including type 2 diabetes (T2DM), hypertension, and obesity increased over 10 times through the last 30 years and it is a severe public health concern worldwide. Uncoupling protein 1 (UCP1) is a mitochondrial carrier protein found only in brown adipose tissue involved in thermogenesis and energy expenditure. Several studies showed an association between UCP1 variants and the susceptibility to MetS, T2DM, and/or obesity in various populations; all these studies were, however, limited to a few selected polymorphisms. The present study aimed to search within the entire UCP1 gene for new variants potentially associated with MetS and/or T2DM risk. We performed NGS sequencing of the entire UCP1 gene in 59 MetS patients including 29 T2DM patients, and 36 controls using the MiSeq platform. An analysis of allele and genotype distribution revealed nine variations which seem to be interesting in the context of MetS and fifteen in the context of T2DM. Altogether, we identified 12 new variants, among which only rs3811787 was investigated previously by others. Thereby, NGS sequencing revealed new intriguing UCP1 gene variants potentially associated with MetS and/or T2DM risk in the Polish population.
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Affiliation(s)
- Anna Andrzejczak
- Laboratory of Genetics and Epigenetics of Human Diseases, Department of Experimental Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland
| | - Agata Witkowicz
- Laboratory of Genetics and Epigenetics of Human Diseases, Department of Experimental Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland
| | - Dorota Kujawa
- Laboratory of Genomics and Bioinformatics, Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland
| | - Damian Skrypnik
- Department of Treatment of Obesity, Metabolic Disorders and Clinical Dietetics, Poznan University of Medical Sciences, 60-569 Poznan, Poland
| | - Monika Szulińska
- Department of Treatment of Obesity, Metabolic Disorders and Clinical Dietetics, Poznan University of Medical Sciences, 60-569 Poznan, Poland
| | - Paweł Bogdański
- Department of Treatment of Obesity, Metabolic Disorders and Clinical Dietetics, Poznan University of Medical Sciences, 60-569 Poznan, Poland
| | - Łukasz Łaczmański
- Laboratory of Genomics and Bioinformatics, Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland
| | - Lidia Karabon
- Laboratory of Genetics and Epigenetics of Human Diseases, Department of Experimental Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland
- Correspondence:
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7
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Aboouf MA, Armbruster J, Thiersch M, Gassmann M, Gödecke A, Gnaiger E, Kristiansen G, Bicker A, Hankeln T, Zhu H, Gorr TA. Myoglobin, expressed in brown adipose tissue of mice, regulates the content and activity of mitochondria and lipid droplets. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159026. [PMID: 34384891 DOI: 10.1016/j.bbalip.2021.159026] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/19/2022]
Abstract
The identification of novel physiological regulators that stimulate energy expenditure through brown adipose tissue (BAT) activity in substrate catalysis is of utmost importance to understand and treat metabolic diseases. Myoglobin (MB), known to store or transport oxygen in heart and skeletal muscles, has recently been found to bind fatty acids with physiological constants in its oxygenated form (i.e., MBO2). Here, we investigated the in vivo effect of MB expression on BAT activity. In particular, we studied mitochondrial function and lipid metabolism as essential determinants of energy expenditure in this tissue. We show in a MB-null (MBko) mouse model that MB expression in BAT impacts on the activity of brown adipocytes in a twofold manner: i) by elevating mitochondrial density plus maximal respiration capacity, and through that, by stimulating BAT oxidative metabolism along with the organelles` uncoupled respiration; and ii) by influencing the free fatty acids pool towards a palmitate-enriched composition and shifting the lipid droplet (LD) equilibrium towards higher counts of smaller droplets. These metabolic changes were accompanied by the up-regulated expression of thermogenesis markers UCP1, CIDEA, CIDEC, PGC1-α and PPAR-α in the BAT of MB wildtype (MBwt) mice. Along with the emergence of the "browning" BAT morphology, MBwt mice exhibited a leaner phenotype when compared to MBko littermates at 20 weeks of age. Our data shed novel insights into MB's role in linking oxygen and lipid-based thermogenic metabolism. The findings suggest potential new strategies of targeting the MB pathway to treat metabolic disorders related to diminishing energy expenditure.
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Affiliation(s)
- Mostafa A Aboouf
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Molecular and Translational Biomedicine PhD Program, Life Science Zurich Graduate School, 8057 Zurich, Switzerland; Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt
| | - Julia Armbruster
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Molecular and Translational Biomedicine PhD Program, Life Science Zurich Graduate School, 8057 Zurich, Switzerland
| | - Markus Thiersch
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Axel Gödecke
- Institute of Cardiovascular Physiology (A.G.), Medical Faculty, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Erich Gnaiger
- Department of Visceral, Transplant and Thoracic Surgery, D. Swarovski Research Laboratory, Medical University Innsbruck, Innrain 66/6, A-6020 Innsbruck, Austria
| | - Glen Kristiansen
- Institute of Pathology, University Hospital Bonn, University of Bonn, D-53127 Bonn, Germany
| | - Anne Bicker
- Institute of Organismic and Molecular Evolution, Molecular Genetics and Genome Analysis, Johannes Gutenberg University, D-55099 Mainz, Germany
| | - Thomas Hankeln
- Institute of Organismic and Molecular Evolution, Molecular Genetics and Genome Analysis, Johannes Gutenberg University, D-55099 Mainz, Germany
| | - Hao Zhu
- Department of Clinical Laboratory Sciences, The University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA; Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Thomas A Gorr
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.
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8
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Mancini C, Gohlke S, Garcia-Carrizo F, Zagoriy V, Stephanowitz H, Schulz TJ. Identification of biomarkers of brown adipose tissue aging highlights the role of dysfunctional energy and nucleotide metabolism pathways. Sci Rep 2021; 11:19928. [PMID: 34620947 PMCID: PMC8497523 DOI: 10.1038/s41598-021-99362-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 09/23/2021] [Indexed: 12/25/2022] Open
Abstract
Brown adipose tissue function declines during aging and may contribute to the onset of metabolic disorders such as diabetes and obesity. Only limited understanding of the mechanisms leading to the metabolic impairment of brown adipocytes during aging exists. To this end, interscapular brown adipose tissue samples were collected from young and aged mice for quantification of differential gene expression and metabolite levels. To identify potential processes involved in brown adipocyte dysfunction, metabolite concentrations were correlated to aging and significantly changed candidates were subsequently integrated with a non-targeted proteomic dataset and gene expression analyses. Our results include novel age-dependent correlations of polar intermediates in brown adipose tissue. Identified metabolites clustered around three biochemical processes, specifically energy metabolism, nucleotide metabolism and vitamin metabolism. One mechanism of brown adipose tissue dysfunction may be linked to mast cell activity, and we identify increased histamine levels in aged brown fat as a potential biomarker. In addition, alterations of genes involved in synthesis and degradation of many metabolites were mainly observed in the mature brown adipocyte fraction as opposed to the stromal vascular fraction. These findings may provide novel insights on the molecular mechanisms contributing to the impaired thermogenesis of brown adipocytes during aging.
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Affiliation(s)
- Carola Mancini
- Department of Adipocyte Development and Nutrition, German Institute of Human Nutrition Potsdam-Rehbrücke, 114-116 Arthur-Scheunert-Allee, 14558, Nuthetal, Germany.,German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Sabrina Gohlke
- Department of Adipocyte Development and Nutrition, German Institute of Human Nutrition Potsdam-Rehbrücke, 114-116 Arthur-Scheunert-Allee, 14558, Nuthetal, Germany
| | - Francisco Garcia-Carrizo
- Department of Adipocyte Development and Nutrition, German Institute of Human Nutrition Potsdam-Rehbrücke, 114-116 Arthur-Scheunert-Allee, 14558, Nuthetal, Germany
| | | | - Heike Stephanowitz
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Tim J Schulz
- Department of Adipocyte Development and Nutrition, German Institute of Human Nutrition Potsdam-Rehbrücke, 114-116 Arthur-Scheunert-Allee, 14558, Nuthetal, Germany. .,German Center for Diabetes Research (DZD), München-Neuherberg, Germany. .,Institute of Nutritional Science, University of Potsdam, Potsdam-Rehbrücke, Nuthetal, Germany.
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9
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Francis CE, Allee L, Nguyen H, Grindstaff RD, Miller CN, Rayalam S. Endocrine disrupting chemicals: Friend or foe to brown and beige adipose tissue? Toxicology 2021; 463:152972. [PMID: 34606950 DOI: 10.1016/j.tox.2021.152972] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 09/17/2021] [Accepted: 09/29/2021] [Indexed: 12/15/2022]
Abstract
The effects of Endocrine Disrupting Chemicals (EDCs) on the current obesity epidemic is a growing field of interest. Numerous EDCs have shown the potential to alter energy metabolism, which may increase the risk of obesity, in part, through direct actions on adipose tissue. While white adipose tissue has historically been the primary focus of this work, evidence of the EDC-induced disruption of brown and beige adipose tissues continues to build. Both brown and beige fat are thermogenic adipose depots rich in mitochondria that dispense heat when activated. Due to these properties, brown and beige fat are implicated in metabolic diseases such as obesity, diabetes, and cachexia. This review delves into the current literature of different EDCs, including bisphenols, dioxins, air pollutants, phthalates, and phytochemicals. The possible implications that these EDCs have on thermogenic adipose tissues are covered. This review also introduces the possibility of using brown and beige fat as a therapeutic target organ by taking advantage of some of the properties of EDCs. Collectively, we provide a comprehensive discussion of the evidence of EDC disruption in white, brown, and beige fat and highlight gaps worthy of further exploration.
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Affiliation(s)
| | - Logan Allee
- Department of Pharmaceutical Sciences, School of Pharmacy, Philadelphia College of Osteopathic Medicine, Georgia Campus, Suwanee, GA, USA
| | - Helen Nguyen
- Oak Ridge Institute for Science and Education, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Rachel D Grindstaff
- Neuroendocrine Toxicology Brach, Public Health and Integrative Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Colette N Miller
- Cardiopulmonary Immunotoxicology Branch, Public Health and Integrative Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA.
| | - Srujana Rayalam
- Department of Pharmaceutical Sciences, School of Pharmacy, Philadelphia College of Osteopathic Medicine, Georgia Campus, Suwanee, GA, USA.
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10
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Jones AE, Sheng L, Acevedo A, Veliova M, Shirihai OS, Stiles L, Divakaruni AS. Forces, fluxes, and fuels: tracking mitochondrial metabolism by integrating measurements of membrane potential, respiration, and metabolites. Am J Physiol Cell Physiol 2020; 320:C80-C91. [PMID: 33147057 DOI: 10.1152/ajpcell.00235.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Assessing mitochondrial function in cell-based systems is a central component of metabolism research. However, the selection of an initial measurement technique may be complicated given the range of parameters that can be studied and the need to define the mitochondrial (dys)function of interest. This methods-focused review compares and contrasts the use of mitochondrial membrane potential measurements, plate-based respirometry, and metabolomics and stable isotope tracing. We demonstrate how measurements of 1) cellular substrate preference, 2) respiratory chain activity, 3) cell activation, and 4) mitochondrial biogenesis are enriched by integrating information from multiple methods. This manuscript is meant to serve as a perspective to help choose which technique might be an appropriate initial method to answer a given question, as well as provide a broad "roadmap" for designing follow-up assays to enrich datasets or resolve ambiguous results.
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Affiliation(s)
- Anthony E Jones
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Li Sheng
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Aracely Acevedo
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Michaela Veliova
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California.,Department of Medicine, University of California, Los Angeles, California
| | - Orian S Shirihai
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California.,Department of Medicine, University of California, Los Angeles, California
| | - Linsey Stiles
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California.,Department of Medicine, University of California, Los Angeles, California
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
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11
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Chitraju C, Fischer AW, Farese RV, Walther TC. Lipid Droplets in Brown Adipose Tissue Are Dispensable for Cold-Induced Thermogenesis. Cell Rep 2020; 33:108348. [PMID: 33147469 PMCID: PMC7696656 DOI: 10.1016/j.celrep.2020.108348] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/29/2020] [Accepted: 10/13/2020] [Indexed: 12/20/2022] Open
Abstract
Brown adipocytes store metabolic energy as triglycerides (TGs) in lipid droplets (LDs). Fatty acids released from brown adipocyte LDs by lipolysis are thought to activate and fuel UCP1-mediated thermogenesis. Here, we test this hypothesis by preventing fatty acid storage in murine brown adipocytes through brown adipose tissue (BAT)-specific deletions of the TG synthesis enzymes DGAT1 and DGAT2 (BA-DGAT KO). Despite the absence of TGs in brown adipocytes, BAT is functional, and BA-DGAT-KO mice maintain euthermia during acute or chronic cold exposure. As apparent adaptations to the lack of TG, brown adipocytes of BA-DGAT-KO mice appear to use circulating glucose and fatty acids, and stored glycogen, to fuel thermogenesis. Moreover, BA-DGAT-KO mice are resistant to diet-induced glucose intolerance, likely because of increased glucose disposal by BAT. We conclude that TGs in BAT are dispensable for its contribution to cold-induced thermogenesis, at least when other fuel sources are available.
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Affiliation(s)
- Chandramohan Chitraju
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Alexander W Fischer
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Robert V Farese
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
| | - Tobias C Walther
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA.
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12
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Duong QV, Hoffman A, Zhong K, Dessinger MJ, Zhang Y, Bazil JN. Calcium overload decreases net free radical emission in cardiac mitochondria. Mitochondrion 2020; 51:126-139. [PMID: 31982614 DOI: 10.1016/j.mito.2020.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/08/2019] [Accepted: 01/08/2020] [Indexed: 12/21/2022]
Abstract
Elevated calcium and reactive oxygen species (ROS) are responsible for the bulk of cell death occurring in a variety of clinical settings that include acute coronary events, cerebrovascular accidents, and acute kidney injury. It is commonly believed that calcium and ROS participate in a viscous cycle during these events. However, the precise feedback mechanisms are unknown. We quantitatively demonstrate in this study that, on the contrary, calcium does not stimulate free radical production but suppresses it. Isolated mitochondria from guinea pig hearts were energized with a variety of substrates and exposed to calcium concentrations designed to induce moderate calcium overload conditions associated with ischemia/reperfusion injury but do not elicit the well-known mitochondrial permeability transition phenomenon. Metabolic function and free radical emission were simultaneously quantified using high-resolution respirometry and fluorimetry. Membrane potential, high amplitude swelling, and calcium dynamics were also quantified in parallel. Our results reveal that calcium overload does not lead to excessive ROS emission but does decrease ADP stimulated respiration rates for NADH-dependent pathways. Moreover, we developed an empirical model of mitochondrial free radical homeostasis to identify the processes that are different for each substrate and calcium condition. In summary, we show that in healthy guinea pig mitochondria, calcium uptake and free radical generation do not contribute to a viscous cycle and that the relationship between net free radical production and oxygen concentration is hyperbolic. Altogether, these results lay out an important foundation necessary to quantitatively determine the role of calcium in IR injury and ROS production.
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Affiliation(s)
- Quynh V Duong
- Department of Biochemistry and Molecular Biology, Michigan State University, United States
| | - Adrianna Hoffman
- Department of Physiology, Michigan State University, United States
| | - Katie Zhong
- Department of Physiology, Michigan State University, United States
| | | | - Yizhu Zhang
- Department of Physiology, Michigan State University, United States
| | - Jason N Bazil
- Department of Physiology, Michigan State University, United States.
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13
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Bast-Habersbrunner A, Fromme T. Purine Nucleotides in the Regulation of Brown Adipose Tissue Activity. Front Endocrinol (Lausanne) 2020; 11:118. [PMID: 32210919 PMCID: PMC7076073 DOI: 10.3389/fendo.2020.00118] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/24/2020] [Indexed: 01/06/2023] Open
Abstract
Non-shivering thermogenesis in mammalian brown adipose tissue is a powerful mechanism to defend normothermia in cold climates. To minimize the loss of chemical energy, the central functional component, mitochondrial uncoupling protein 1, UCP1, must be tightly regulated. The canonical pathway of UCP1 activation includes lipolytic release of free fatty acids in response to an adrenergic signal. Activating fatty acids overcome constitutive inhibition of UCP1 by the di- and triphosphate forms of purine nucleotides, i.e., ATP, ADP, GTP, and GDP. Cellular concentrations of inhibitory, free nucleotides are subject to significant, adrenergically induced alterations. The regulatory components involved may constitute novel drug targets to manipulate brown fat thermogenesis and thereby organismic energy balance. We here review evidence for and against a dominant role of nucleotides in thermogenic control, describe conceptual routes to endogenously and pharmacologically alter free nucleotide pool size, speculate on a signaling role of degradation products released from active brown fat, and highlight gaps in our understanding of signaling and metabolic pathways involved.
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Affiliation(s)
- Andrea Bast-Habersbrunner
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Munich, Germany
- EKFZ - Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Munich, Germany
| | - Tobias Fromme
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Munich, Germany
- EKFZ - Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Munich, Germany
- *Correspondence: Tobias Fromme
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14
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Klaus S, Ost M. Mitochondrial uncoupling and longevity - A role for mitokines? Exp Gerontol 2019; 130:110796. [PMID: 31786315 DOI: 10.1016/j.exger.2019.110796] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/15/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022]
Abstract
Aging has been viewed both as a random process due to accumulation of molecular and cellular damage over time and as a programmed process linked to cellular pathway important for growth and maturation. These views converge on mitochondria as both the major producer of damaging reactive oxidant species (ROS) and as signaling organelles. A finite proton leak across the inner mitochondrial membrane leading to a slight uncoupling of oxidative phosphorylation and respiration is an intrinsic property of all mitochondria and according to the "uncoupling to survive" hypothesis it has evolved to protect against ROS production to minimize oxidative damage. This hypothesis is supported by evidence linking an increased endogenous, uncoupling protein (UCP1) mediated, as well as experimentally induced mitochondrial uncoupling to an increased lifespan in rodents. This is possibly due to the synergistic activation of molecular pathways linked to life extending effects of caloric restriction as well as a mitohormetic response. Mitohormesis is an adaptive stress response through mitonuclear signaling which increases stress resistance resulting in health promoting effects. Part of this response is the induction of fibroblast growth factor 21 (FGF21) and growth and differentiation factor 15 (GDF15), two stress-induced mitokines which elicit beneficial systemic metabolic effects via endocrine action.
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Affiliation(s)
- Susanne Klaus
- German Institute of Human Nutrition in Potsdam Rehbrücke, Nuthetal, Germany; University of Potsdam, Institute of Nutritional Science, Potsdam, Germany.
| | - Mario Ost
- German Institute of Human Nutrition in Potsdam Rehbrücke, Nuthetal, Germany
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