51
|
Abstract
In the midst of an obesity epidemic, the promotion of brown adipose tissue (BAT) function and the browning of white adipose tissue (WAT) have emerged as promising therapeutic targets to increase energy expenditure and counteract weight gain. Despite the fact that the thermogenic potential of bone fide BAT in rodents is several orders of magnitudes higher than white fat containing brite/beige adipocytes, WAT browning represents a particularly intriguing concept in humans given the extreme amount of excess WAT in obese individuals. In addition, the clear distinction between classic brown and beige fat that has been proposed in mice does not exist in humans. In fact, studies of human BAT biopsies found controversial results suggesting both classic brown and beige characteristics. Irrespective of the true ‘color’, accumulating evidence suggests the induction of thermogenic adipocytes in human WAT depots in response to specific stimuli, highlighting that WAT browning may occur in both, mice and humans. These observations also emphasize the great plasticity of human fat depots and raise important questions about the metabolic properties of thermogenically active adipose tissue in humans and the potential therapeutic implications. We will first review the cellular and molecular aspects of selected adipose tissue browning concepts that have been identified in mouse models with emphasis on neuronal factors, the microbiome, immune cells and several hormones. We will also summarize the evidence for adipose tissue browning in humans including some experimental pharmacologic approaches.
Collapse
Affiliation(s)
- Carsten T Herz
- Clinical Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Florian W Kiefer
- Clinical Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
52
|
Kaisanlahti A, Glumoff T. Browning of white fat: agents and implications for beige adipose tissue to type 2 diabetes. J Physiol Biochem 2018; 75:1-10. [PMID: 30506389 PMCID: PMC6513802 DOI: 10.1007/s13105-018-0658-5] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/31/2018] [Indexed: 12/23/2022]
Abstract
Mammalian adipose tissue is traditionally categorized into white and brown relating to their function and morphology: while white serves as an energy storage, brown adipose tissue acts as the heat generator maintaining the core body temperature. The most recently identified type of fat, beige adipocyte tissue, resembles brown fat by morphology and function but is developmentally more related to white. The synthesis of beige fat, so-called browning of white fat, has developed into a topical issue in diabetes and metabolism research. This is due to its favorable effect on whole-body energy metabolism and the fact that it can be recruited during adult life. Indeed, brown and beige adipose tissues have been demonstrated to play a role in glucose homeostasis, insulin sensitivity, and lipid metabolism—all factors related to pathogenesis of type 2 diabetes. Many agents capable of initiating browning have been identified so far and tested widely in humans and animal models including in vitro and in vivo experiments. Interestingly, several agents demonstrated to have browning activity are in fact secreted as adipokines from brown and beige fat tissue, suggesting a physiological relevance both in beige adipocyte recruitment processes and in maintenance of metabolic homeostasis. The newest findings on agents driving beige fat recruitment, their mechanisms, and implications on type 2 diabetes are discussed in this review.
Collapse
MESH Headings
- Adipose Tissue, Beige/drug effects
- Adipose Tissue, Beige/metabolism
- Adipose Tissue, Beige/pathology
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/pathology
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Adipose Tissue, White/pathology
- Animals
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Energy Metabolism/drug effects
- Energy Metabolism/genetics
- Glucagon-Like Peptide 1/pharmacology
- Glucose/metabolism
- Humans
- Insulin Resistance
- Leptin/pharmacology
- Lipid Metabolism/drug effects
- Lipid Metabolism/genetics
- Lipotropic Agents/pharmacology
- Melatonin/pharmacology
- Natriuretic Peptides/pharmacology
- Thermogenesis/drug effects
- Thermogenesis/genetics
- Tretinoin/pharmacology
Collapse
Affiliation(s)
- A Kaisanlahti
- Biocenter Oulu/Cancer Research and Translational Medicine Research Unit, University of Oulu, Aapistie 5, P.O. Box 5281, 90014, Oulu, Finland.
| | - T Glumoff
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7A, P.O Box 5400, 90014, Oulu, Finland
| |
Collapse
|
53
|
den Hartigh LJ, Goodspeed L, Wang SA, Kenerson HL, Omer M, O'Brien KD, Ladiges W, Yeung R, Subramanian S. Chronic oral rapamycin decreases adiposity, hepatic triglycerides and insulin resistance in male mice fed a diet high in sucrose and saturated fat. Exp Physiol 2018; 103:1469-1480. [PMID: 30117227 DOI: 10.1113/ep087207] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 08/09/2018] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Whether chronic oral rapamycin promotes beneficial effects on glucose/lipid metabolism and energy balance when administered to mice with an obesogenic diet rich in saturated fat and sucrose has not been explored. What is the main finding and its importance? Chronic oral rapamycin reduces body weight and fat gain, improves insulin sensitivity and reduces hepatic steatosis when administered to mice with a high-fat, high-sucrose diet. In addition, we make the new observation that there appear to be tissue-specific effects of rapamycin. Although rapamycin appears to impart its effects mainly on visceral adipose tissue, its effects on insulin sensitivity are mediated by subcutaneous adipose tissue. ABSTRACT Excess adiposity is commonly associated with insulin resistance, which can increase the risk of cardiovascular disease. However, the exact molecular mechanisms by which obesity results in insulin resistance are yet to be understood clearly. The intracellular nutrient-sensing protein, mechanistic target of rapamycin (mTOR), is a crucial signalling component in the development of obesity-associated insulin resistance. Given that increased tissue activation of mTOR complex-1 (mTORC1) occurs in obesity, diabetes and ageing, we hypothesized that pharmacological inhibition of mTORC1 would improve metabolic dysregulation in diet-induced obesity. We administered continuous rapamycin, a specific mTORC1 inhibitor, orally to C57BL/6J mice concurrently with a high-fat, high-sucrose (HFHS) diet for 20 weeks. The control group received placebo microcapsules. Rapamycin-treated mice showed significantly reduced weight gain and adiposity (33.6 ± 4.9 versus 40.4 ± 3.0% body fat, P < 0.001, n = 8 mice per group), despite increased or equivalent food intake compared with the placebo group. The rapamycin-fed mice also demonstrated reduced plasma glucose (252 ± 57 versus 297 ± 67 mg dl-1 , P < 0.001) and improved insulin sensitivity during insulin and glucose tolerance testing. Rapamycin-treated mice also had lower plasma triglycerides (48 ± 13 versus 67 ± 11 mg/dL, P < 0.01) and hepatic triglyceride content (89 ± 15 versus 110 ± 19 mg/g liver, P < 0.05) compared with the placebo group. A moderately low dose of rapamycin decreased adiposity and improved the metabolic profile in a model of diet-induced obesity. These data suggest that low-grade chronic mTORC1 inhibition might be a potential strategy for anti-obesity therapies.
Collapse
Affiliation(s)
- Laura J den Hartigh
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Leela Goodspeed
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Shari A Wang
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Heidi L Kenerson
- Department of Surgery, University of Washington, Seattle, WA, 98019, USA
| | - Mohamed Omer
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Kevin D O'Brien
- Diabetes Institute, University of Washington, Seattle, WA, 98019, USA.,Division of Cardiology, University of Washington, Seattle, WA, 98019, USA
| | - Warren Ladiges
- Department of Comparative Medicine, University of Washington, Seattle, WA, 98019, USA
| | - Raymond Yeung
- Department of Surgery, University of Washington, Seattle, WA, 98019, USA
| | - Savitha Subramanian
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| |
Collapse
|
54
|
Lertsuwan J, Lertsuwan K, Sawasdichai A, Tasnawijitwong N, Lee KY, Kitchen P, Afford S, Gaston K, Jayaraman PS, Satayavivad J. CX-4945 Induces Methuosis in Cholangiocarcinoma Cell Lines by a CK2-Independent Mechanism. Cancers (Basel) 2018; 10:E283. [PMID: 30142881 PMCID: PMC6162756 DOI: 10.3390/cancers10090283] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 08/20/2018] [Accepted: 08/20/2018] [Indexed: 02/06/2023] Open
Abstract
Cholangiocarcinoma is a disease with a poor prognosis and increasing incidence and hence there is a pressing unmet clinical need for new adjuvant treatments. Protein kinase CK2 (previously casein kinase II) is a ubiquitously expressed protein kinase that is up-regulated in multiple cancer cell types. The inhibition of CK2 activity using CX-4945 (Silmitasertib) has been proposed as a novel treatment in multiple disease settings including cholangiocarcinoma. Here, we show that CX-4945 inhibited the proliferation of cholangiocarcinoma cell lines in vitro. Moreover, CX-4945 treatment induced the formation of cytosolic vacuoles in cholangiocarcinoma cell lines and other cancer cell lines. The vacuoles contained extracellular fluid and had neutral pH, features characteristic of methuosis. In contrast, simultaneous knockdown of both the α and α' catalytic subunits of protein kinase CK2 using small interfering RNA (siRNA) had little or no effect on the proliferation of cholangiocarcinoma cell lines and failed to induce the vacuole formation. Surprisingly, low doses of CX-4945 increased the invasive properties of cholangiocarcinoma cells due to an upregulation of matrix metallopeptidase 7 (MMP-7), while the knockdown of CK2 inhibited cell invasion. Our data suggest that CX-4945 inhibits cell proliferation and induces cell death via CK2-independent pathways. Moreover, the increase in cell invasion brought about by CX-4945 treatment suggests that this drug might increase tumor invasion in clinical settings.
Collapse
Affiliation(s)
- Jomnarong Lertsuwan
- Laboratory of Chemical Carcinogenesis, Chulabhorn Research Institute, Bangkok 10210, Thailand.
| | - Kornkamon Lertsuwan
- Department of Biochemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
| | - Anyaporn Sawasdichai
- Laboratory of Chemical Carcinogenesis, Chulabhorn Research Institute, Bangkok 10210, Thailand.
| | | | - Ka Ying Lee
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Philip Kitchen
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Simon Afford
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, UK.
| | - Kevin Gaston
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Padma-Sheela Jayaraman
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Jutamaad Satayavivad
- Laboratory of Pharmacology, Chulabhorn Research Institute, Bangkok 10210, Thailand.
| |
Collapse
|
55
|
Jordan J, Birkenfeld AL, Melander O, Moro C. Natriuretic Peptides in Cardiovascular and Metabolic Crosstalk: Implications for Hypertension Management. Hypertension 2018; 72:270-276. [PMID: 29941512 DOI: 10.1161/hypertensionaha.118.11081] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jens Jordan
- From the Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany (J.J.) .,University of Cologne, Germany (J.J.)
| | - Andreas L Birkenfeld
- Medical Clinic III, Paul Langerhans Institute Dresden, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Germany (A.L.B.).,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany (A.L.B.).,Division of Diabetes and Nutritional Sciences, Rayne Institute, King's College London, United Kingdom (A.L.B.)
| | - Olle Melander
- Department of Clinical Sciences, Lund University (O.M.).,Department of Internal Medicine (O.M.)
| | - Cedric Moro
- Skåne University Hospital, Malmö, Sweden; Obesity Research Laboratory, INSERM, UMR1048, Institute of Metabolic and Cardiovascular Diseases, Toulouse, France (C.M.).,UMR1048, Paul Sabatier University, University of Toulouse, France (C.M.)
| |
Collapse
|
56
|
Dinas PC, Nintou E, Psychou D, Granzotto M, Rossato M, Vettor R, Jamurtas AZ, Koutedakis Y, Metsios GS, Flouris AD. Association of fat mass profile with natriuretic peptide receptor alpha in subcutaneous adipose tissue of medication-free healthy men: A cross-sectional study. F1000Res 2018; 7:327. [PMID: 30079239 PMCID: PMC6053697 DOI: 10.12688/f1000research.14198.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/16/2018] [Indexed: 01/16/2023] Open
Abstract
Background: Atrial natriuretic peptide increases lipolysis in human adipocytes by binding to natriuretic peptide receptor-A (NPRA). The aim of the current study was to examine the associations of NPRA mRNA of subcutaneous adipose tissue with fat mass, fat-free mass, body mass index (BMI) and arterial blood pressure in medication-free healthy men. Method: Thirty-two volunteers [age (years): 36.06±7.36, BMI: 27.60±4.63 (kg/m 2)] underwent assessments of body height/weight, % fat mass, fat-free mass (kg), blood pressure, and a subcutaneous adipose tissue biopsy via a surgical technique. Results: We found that NPRA mRNA was negatively associated with % fat mass (r=-0.40, R 2=0.16, p=0.03) and BMI (r=-0.45, R 2=0.20, p=0.01). Cohen's f 2 effect size analyses showed a small effect size between NPRA mRNA and BMI ( f 2 =0.25). One-way analysis of variance with Bonferroni post-hoc tests showed a tendency for mean differences of NPRA mRNA across BMI categories (p=0.06). This was confirmed by Cohen's d effect size analyses revealing a large effect size of NPRA mRNA between obese individuals (BMI≥30 kg/m 2) and either normal weight (BMI=19-25 kg/m 2; d=0.94) or overweight (BMI=25-30 kg/m 2; d=1.12) individuals. Conclusions: NPRA mRNA is negatively associated with % fat mass and BMI in medication-free healthy men, suggesting a possible role of NPRA in the control of fat mass accumulation.
Collapse
Affiliation(s)
- Petros C. Dinas
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
- Institute of Sport, Faculty of Education Health and Wellbeing, University of Wolverhampton, Walsall, UK
| | - Eleni Nintou
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Dimitra Psychou
- School of Physical Education and Exercise Science, University of Thessaly, Trikala, Greece
| | - Marnie Granzotto
- Department of Medicine – DIMED, Internal Medicine 3, University of Padova, Padova , Italy
| | - Marco Rossato
- Department of Medicine – DIMED, Internal Medicine 3, University of Padova, Padova , Italy
| | - Roberto Vettor
- Department of Medicine – DIMED, Internal Medicine 3, University of Padova, Padova , Italy
| | - Athanasios Z. Jamurtas
- School of Physical Education and Exercise Science, University of Thessaly, Trikala, Greece
| | - Yiannis Koutedakis
- Institute of Sport, Faculty of Education Health and Wellbeing, University of Wolverhampton, Walsall, UK
- School of Physical Education and Exercise Science, University of Thessaly, Trikala, Greece
| | - George S. Metsios
- Institute of Sport, Faculty of Education Health and Wellbeing, University of Wolverhampton, Walsall, UK
| | - Andreas D. Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| |
Collapse
|