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Behrens J, Braren I, Jaeckstein MY, Lilie L, Heine M, Sass F, Sommer J, Silbert-Wagner D, Fuh MM, Worthmann A, Straub L, Moustafa T, Heeren J, Scheja L. An efficient AAV vector system of Rec2 serotype for intravenous injection to study metabolism in brown adipocytes in vivo. Mol Metab 2024; 88:101999. [PMID: 39094948 DOI: 10.1016/j.molmet.2024.101999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 07/12/2024] [Accepted: 07/26/2024] [Indexed: 08/04/2024] Open
Abstract
OBJECTIVE Recombinant adeno-associated virus (rAAV) vectors are powerful tools for the sustained expression of proteins in vivo and have been successfully used for mechanistic studies in mice. A major challenge associated with this method is to obtain tissue specificity and high expression levels without need of local virus administration. METHODS To achieve this goal for brown adipose tissue (BAT), we developed a rAAV vector for intravenous bolus injection, which includes an expression cassette comprising an uncoupling protein-1 enhancer-promoter for transcription in brown adipocytes and miR122 target sequences for suppression of expression in the liver, combined with packaging in serotype Rec2 capsid protein. To test tissue specificity, we used a version of this vector expressing Cre recombinase to transduce mice with floxed alleles to knock out MLXIPL (ChREBP) or tdTomato-Cre reporter mice. RESULTS We demonstrated efficient Cre-dependent recombination in interscapular BAT and variable effects in minor BAT depots, but little or no efficacy in white adipose tissues, liver and other organs. Direct overexpression of glucose transporter SLC2A1 (GLUT1) using the rAAV vector in wild type mice resulted in increased glucose uptake and glucose-dependent gene expression in BAT, indicating usefulness of this vector to increase the function even of abundant proteins. CONCLUSION Taken together, we describe a novel brown adipocyte-specific rAAV method to express proteins for loss-of-function and gain-of-function metabolic studies. The approach will enable researchers to access brown fat swiftly, reduce animal breeding time and costs, as well as enable the creation of new transgenic mouse models combining multiple transgenes.
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Affiliation(s)
- Janina Behrens
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ingke Braren
- Vector Facility, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michelle Y Jaeckstein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Luka Lilie
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Markus Heine
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Finnja Sass
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Judith Sommer
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Dagmar Silbert-Wagner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Marceline M Fuh
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anna Worthmann
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Leon Straub
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tarek Moustafa
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Gómez-Hernández A, de las Heras N, Gálvez BG, Fernández-Marcelo T, Fernández-Millán E, Escribano Ó. New Mediators in the Crosstalk between Different Adipose Tissues. Int J Mol Sci 2024; 25:4659. [PMID: 38731880 PMCID: PMC11083914 DOI: 10.3390/ijms25094659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024] Open
Abstract
Adipose tissue is a multifunctional organ that regulates many physiological processes such as energy homeostasis, nutrition, the regulation of insulin sensitivity, body temperature, and immune response. In this review, we highlight the relevance of the different mediators that control adipose tissue activity through a systematic review of the main players present in white and brown adipose tissues. Among them, inflammatory mediators secreted by the adipose tissue, such as classical adipokines and more recent ones, elements of the immune system infiltrated into the adipose tissue (certain cell types and interleukins), as well as the role of intestinal microbiota and derived metabolites, have been reviewed. Furthermore, anti-obesity mediators that promote the activation of beige adipose tissue, e.g., myokines, thyroid hormones, amino acids, and both long and micro RNAs, are exhaustively examined. Finally, we also analyze therapeutic strategies based on those mediators that have been described to date. In conclusion, novel regulators of obesity, such as microRNAs or microbiota, are being characterized and are promising tools to treat obesity in the future.
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Affiliation(s)
- Almudena Gómez-Hernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
| | - Natalia de las Heras
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain;
| | - Beatriz G. Gálvez
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
| | - Tamara Fernández-Marcelo
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
| | - Elisa Fernández-Millán
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
| | - Óscar Escribano
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal, s/n, 28040 Madrid, Spain; (A.G.-H.); (B.G.G.); (T.F.-M.); (E.F.-M.)
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
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3
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Li T, Tian J, Wu M, Tian Y, Li Z. Electroacupuncture stimulation improves cognitive ability and regulates metabolic disorders in Alzheimer's disease model mice: new insights from brown adipose tissue thermogenesis. Front Endocrinol (Lausanne) 2024; 14:1330565. [PMID: 38283741 PMCID: PMC10811084 DOI: 10.3389/fendo.2023.1330565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/26/2023] [Indexed: 01/30/2024] Open
Abstract
Background Metabolic defects play a crucial role in Alzheimer's disease (AD) development. Brown adipose tissue (BAT) has been identified as a novel potential therapeutic target for AD due to its unique role in energy metabolism. Electroacupuncture (EA) shows promise in improving cognitive ability and brain glucose metabolism in AD, but its effects on peripheral and central metabolism are unclear. Methods In this study, SAMP8 mice (AD model) received EA stimulation at specific acupoints. Cognitive abilities were evaluated using the Morris water maze test, while neuronal morphology and tau pathology were assessed through Nissl staining and immunofluorescence staining, respectively. Metabolic variations and BAT thermogenesis were measured using ELISA, HE staining, Western blotting, and infrared thermal imaging. Results Compared to SAMR1 mice, SAMP8 mice showed impaired cognitive ability, neuronal damage, disrupted thermoregulation, and metabolic disorders with low BAT activity. Both the EA and DD groups improved cognitive ability and decreased tau phosphorylation (p<0.01 or p<0.05). However, only the EA group had a significant effect on metabolic disorders and BAT thermogenesis (p<0.01 or p<0.05), while the DD group did not. Conclusion These findings indicate that EA not only improves the cognitive ability of SAMP8 mice, but also effectively regulates peripheral and central metabolic disorders, with this effect being significantly related to the activation of BAT thermogenesis.
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Affiliation(s)
- Ting Li
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Junjian Tian
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Meng Wu
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Yuanshuo Tian
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Zhigang Li
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
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Jalloul W, Moscalu M, Moscalu R, Jalloul D, Grierosu IC, Gutu M, Haba D, Mocanu V, Gutu MM, Stefanescu C. Are MTV and TLG Accurate for Quantifying the Intensity of Brown Adipose Tissue Activation? Biomedicines 2024; 12:151. [PMID: 38255256 PMCID: PMC10813038 DOI: 10.3390/biomedicines12010151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 12/31/2023] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
Recent research has suggested that one novel mechanism of action for anti-obesity medications is to stimulate the activation of brown adipose tissue (BAT). 18FDG PET/CT remains the gold standard for defining and quantifying BAT. SUVmax is the most often used quantification tool in clinical practice. However, this parameter does not reflect the entire BAT volume. As a potential method for precisely evaluating BAT, we have utilised metabolic tumour volume (MTV) and total lesion glycolysis (TLG) to answer the question: Are MTV and TLG accurate in quantifying the intensity of BAT activation? After analysing the total number of oncological 18F-FDG PET/CT scans between 2021-2023, we selected patients with active BAT. Based on the BAT SUVmax, the patients were divided into BAT-moderate activation (MA) vs. BAT-high activation (HA). Furthermore, we statistically analysed the accuracy of TLG and MTV in assessing BAT activation intensity. The results showed that both parameters increased their predictive value regarding BAT activation, and presented a significantly high sensitivity and specificity for the correct classification of BAT activation intensity. To conclude, these parameters could be important indicators with increased accuracy for classifying BAT expression, and could bring additional information about the volume of BAT to complement the limitations of the SUVmax.
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Affiliation(s)
- Wael Jalloul
- Department of Biophysics and Medical Physics-Nuclear Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (W.J.); (D.J.); (I.C.G.); (C.S.)
| | - Mihaela Moscalu
- Department of Preventive Medicine and Interdisciplinarity, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
| | - Roxana Moscalu
- Manchester Academic Health Science Centre, Cell Matrix Biology and Regenerative Medicine, The University of Manchester, Manchester M13 9PT, UK;
| | - Despina Jalloul
- Department of Biophysics and Medical Physics-Nuclear Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (W.J.); (D.J.); (I.C.G.); (C.S.)
| | - Irena Cristina Grierosu
- Department of Biophysics and Medical Physics-Nuclear Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (W.J.); (D.J.); (I.C.G.); (C.S.)
| | - Mihaela Gutu
- County Hospital of Emergency “Saint John the New”, 720224 Suceava, Romania; (M.G.); (M.M.G.)
| | - Danisia Haba
- Department 1 Surgery, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Veronica Mocanu
- Department of Morpho-Functional Sciences (Pathophysiology), “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Mihai Marius Gutu
- County Hospital of Emergency “Saint John the New”, 720224 Suceava, Romania; (M.G.); (M.M.G.)
| | - Cipriana Stefanescu
- Department of Biophysics and Medical Physics-Nuclear Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (W.J.); (D.J.); (I.C.G.); (C.S.)
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Lyu QR, Fu K. Tissue-specific Cre driver mice to study vascular diseases. Vascul Pharmacol 2023; 153:107241. [PMID: 37923099 DOI: 10.1016/j.vph.2023.107241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
Vascular diseases, including atherosclerosis and abdominal aneurysms, are the primary cause of mortality and morbidity among the elderly worldwide. The life quality of patients is significantly compromised due to inadequate therapeutic approaches and limited drug targets. To expand our comprehension of vascular diseases, gene knockout (KO) mice, especially conditional knockout (cKO) mice, are widely used for investigating gene function and mechanisms of action. The Cre-loxP system is the most common method for generating cKO mice. Numerous Cre driver mice have been established to study the main cell types that compose blood vessels, including endothelial cells, smooth muscle cells, and fibroblasts. Here, we first discuss the characteristics of each layer of the arterial wall. Next, we provide an overview of the representative Cre driver mice utilized for each of the major cell types in the vessel wall and their most recent applications in vascular biology. We then go over Cre toxicity and discuss the practical methods for minimizing Cre interference in experimental outcomes. Finally, we look into the future of tissue-specific Cre drivers by introducing the revolutionary single-cell RNA sequencing and dual recombinase system.
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Affiliation(s)
- Qing Rex Lyu
- Medical Research Center, Chongqing General Hospital, Chongqing 401147, China; Chongqing Academy of Medical Sciences, Chongqing 401147, China.
| | - Kailong Fu
- Department of Traditional Chinese Medicine, Fujian Medical University Union Hospital, Fuzhou 350001, China.
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Chen CM, Meng XQ, Zhu H, Liu T, Liu Y, Zhou LJ, Zhu GD, Chen XB, Guo XG, Duan SZ. Brown adipocyte mineralocorticoid receptor deficiency impairs metabolic regulation in diet-induced obese mice. J Lipid Res 2023; 64:100449. [PMID: 37734559 PMCID: PMC10622702 DOI: 10.1016/j.jlr.2023.100449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/01/2023] [Accepted: 09/10/2023] [Indexed: 09/23/2023] Open
Abstract
Activation of brown adipose tissue (BAT) contributes to energy dissipation and metabolic health. Although mineralocorticoid receptor (MR) antagonists have been demonstrated to improve metabolism under obesity, the underlying mechanisms remain incompletely understood. We aimed to evaluate the role of BAT MR in metabolic regulation. After 8 weeks of high-fat diet (HFD) feeding, BAT MR KO (BMRKO) mice manifested significantly increased bodyweight, fat mass, serum fasting glucose, and impaired glucose homeostasis compared with littermate control (LC) mice, although insulin resistance and fasting serum insulin were not significantly changed. Metabolic cage experiments showed no change in O2 consumption, CO2 production, or energy expenditure in obese BMRKO mice. RNA sequencing analysis revealed downregulation of genes related to fatty acid metabolism in BAT of BMRKO-HFD mice compared with LC-HFD mice. Moreover, H&E and immunohistochemical staining demonstrated that BMRKO exacerbated HFD-induced macrophage infiltration and proinflammatory genes in epididymal white adipose tissue (eWAT). BMRKO-HFD mice also manifested significantly increased liver weights and hepatic lipid accumulation, an increasing trend of genes related to lipogenesis and lipid uptake, and significantly decreased genes related to lipolytic and fatty acid oxidation in the liver. Finally, the level of insulin-induced AKT phosphorylation was substantially blunted in eWAT but not liver or skeletal muscle of BMRKO-HFD mice compared with LC-HFD mice. These data suggest that BAT MR is required to maintain metabolic homeostasis, likely through its regulation of fatty acid metabolism in BAT and impacts on eWAT and liver.
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Affiliation(s)
- Chu-Mao Chen
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China; Hongqiao International Institute of Medicine, Shanghai Tongren Hospital/Faculty of Basic Medicine, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Qian Meng
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Hong Zhu
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Ting Liu
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Yuan Liu
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Lu-Jun Zhou
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Guo-Dong Zhu
- Department of Oncology, Guangzhou Geriatric Hospital, Guangzhou, China
| | - Xiao-Bei Chen
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China.
| | - Xu-Guang Guo
- Department of Clinical Laboratory Medicine, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China; Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, China; Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, King Med School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, China; Department of Teaching Management, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
| | - Sheng-Zhong Duan
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China; Shanghai Key Laboratory of Hypertension, Shanghai Institute of Hypertension, Shanghai, China.
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Weidlinger S, Winterberger K, Pape J, Weidlinger M, Janka H, von Wolff M, Stute P. Impact of estrogens on resting energy expenditure: A systematic review. Obes Rev 2023; 24:e13605. [PMID: 37544655 DOI: 10.1111/obr.13605] [Citation(s) in RCA: 6] [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: 10/18/2022] [Revised: 06/13/2023] [Accepted: 06/23/2023] [Indexed: 08/08/2023]
Abstract
The fear of weight gain is one of the main reasons for women not to initiate or to early discontinue hormonal contraception or menopausal hormone therapy. Resting energy expenditure is by far the largest component and the most important determinant of total energy expenditure. Given that low resting energy expenditure is a confirmed predictive factor for weight gain and consecutively for the development of obesity, research into the influence of sex steroids on resting energy expenditure is a particularly exciting area. The objective of this systematic review was to evaluate the effects of medication with natural and synthetic estrogens on resting energy expenditure in healthy normal weight and overweight women. Through complex systematic literature searches, a total of 10 studies were identified that investigated the effects of medication with estrogens on resting energy expenditure. Our results demonstrate that estrogen administration increases resting energy expenditure by up to +208 kcal per day in the context of contraception and by up to +222 kcal per day in the context of menopausal hormone therapy, suggesting a preventive effect of circulating estrogen levels and estrogen administration on weight gain and obesity development.
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Affiliation(s)
- Susanna Weidlinger
- Department of Obstetrics and Gynecology, University Hospital of Bern, Bern, Switzerland
| | - Katja Winterberger
- Department of Obstetrics and Gynecology, University Hospital of Bern, Bern, Switzerland
| | - Janna Pape
- Department of Obstetrics and Gynecology, University Hospital of Bern, Bern, Switzerland
| | | | - Heidrun Janka
- Medical Library, University Library Bern, University of Bern, Bern, Switzerland
| | - Michael von Wolff
- Department of Obstetrics and Gynecology, University Hospital of Bern, Bern, Switzerland
| | - Petra Stute
- Department of Obstetrics and Gynecology, University Hospital of Bern, Bern, Switzerland
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8
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Efthymiou V, Ding L, Balaz M, Sun W, Balazova L, Straub LG, Dong H, Simon E, Ghosh A, Perdikari A, Keller S, Ghoshdastider U, Horvath C, Moser C, Hamilton B, Neubauer H, Wolfrum C. Inhibition of AXL receptor tyrosine kinase enhances brown adipose tissue functionality in mice. Nat Commun 2023; 14:4162. [PMID: 37443109 PMCID: PMC10344962 DOI: 10.1038/s41467-023-39715-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
The current obesity epidemic and high prevalence of metabolic diseases necessitate efficacious and safe treatments. Brown adipose tissue in this context is a promising target with the potential to increase energy expenditure, however no pharmacological treatments activating brown adipose tissue are currently available. Here, we identify AXL receptor tyrosine kinase as a regulator of adipose function. Pharmacological and genetic inhibition of AXL enhance thermogenic capacity of brown and white adipocytes, in vitro and in vivo. Mechanistically, these effects are mediated through inhibition of PI3K/AKT/PDE signaling pathway, resulting in induction of nuclear FOXO1 localization and increased intracellular cAMP levels via PDE3/4 inhibition and subsequent stimulation of the PKA-ATF2 pathway. In line with this, both constitutive Axl deletion as well as inducible adipocyte-specific Axl deletion protect animals from diet-induced obesity concomitant with increases in energy expenditure. Based on these data, we propose AXL receptor as a target for the treatment of obesity.
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Affiliation(s)
- Vissarion Efthymiou
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
- Joslin Diabetes Center, Section of Integrative Physiology and Metabolism, Research Division, Harvard Medical School, Boston, MA, USA
| | - Lianggong Ding
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
| | - Miroslav Balaz
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
- Laboratory of Cellular and Molecular Metabolism, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Wenfei Sun
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Lucia Balazova
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
- Laboratory of Cellular and Molecular Metabolism, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Leon G Straub
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
- Institute of Child Nutrition, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
| | - Hua Dong
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Eric Simon
- Department of Global Computational Biology and Digital Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Adhideb Ghosh
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
| | - Aliki Perdikari
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
| | - Svenja Keller
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
- Mechanisms of Inherited Kidney Diseases Group, Institute of Physiology, University of Zurich, 8057, Zurich, Switzerland
| | - Umesh Ghoshdastider
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
| | - Carla Horvath
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
| | - Caroline Moser
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland
| | - Bradford Hamilton
- Department of CardioMetabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Heike Neubauer
- Department of CardioMetabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Christian Wolfrum
- ETH Zürich - Swiss Federal Institute of Technology, Department of Health Sciences and Technology, Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Schwerzenbach, Switzerland.
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Kwon J, Yeh YS, Kawarasaki S, Minamino H, Fujita Y, Okamatsu-Ogura Y, Takahashi H, Nomura W, Matsumura S, Yu R, Kimura K, Saito M, Inagaki N, Inoue K, Kawada T, Goto T. Mevalonate biosynthesis pathway regulates the development and survival of brown adipocytes. iScience 2023; 26:106161. [PMID: 36895651 PMCID: PMC9988578 DOI: 10.1016/j.isci.2023.106161] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 01/08/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023] Open
Abstract
The high thermogenic activity of brown adipose tissue (BAT) has received considerable attention. Here, we demonstrated the role of the mevalonate (MVA) biosynthesis pathway in the regulation of brown adipocyte development and survival. The inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme in the MVA pathway and the molecular target of statins, suppressed brown adipocyte differentiation by suppressing protein geranylgeranylation-mediated mitotic clonal expansion. The development of BAT in neonatal mice exposed to statins during the fetal period was severely impaired. Moreover, statin-induced geranylgeranyl pyrophosphate (GGPP) deficiency led to the apoptosis of mature brown adipocytes. Brown adipocyte-specific Hmgcr knockout induced BAT atrophy and disrupted thermogenesis. Importantly, both genetic and pharmacological inhibition of HMGCR in adult mice induced morphological changes in BAT accompanied by an increase in apoptosis, and statin-treated diabetic mice showed worsened hyperglycemia. These findings revealed that MVA pathway-generated GGPP is indispensable for BAT development and survival.
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Affiliation(s)
- Jungin Kwon
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan
| | - Yu-Sheng Yeh
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan
| | - Satoko Kawarasaki
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan
| | - Hiroto Minamino
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Yoshihito Fujita
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Yuko Okamatsu-Ogura
- Departments of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Haruya Takahashi
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan
| | - Wataru Nomura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan.,Research Unit for Physiological Chemistry, the Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 606-8501, Japan
| | - Shigenobu Matsumura
- Division of Clinical Nutrition, Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Osaka 583-0872, Japan
| | - Rina Yu
- Department of Food Science and Nutrition, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Kazuhiro Kimura
- Departments of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Masayuki Saito
- Departments of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology, and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Kazuo Inoue
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan.,Research Unit for Physiological Chemistry, the Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 606-8501, Japan
| | - Teruo Kawada
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan.,Research Unit for Physiological Chemistry, the Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 606-8501, Japan
| | - Tsuyoshi Goto
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011, Japan.,Research Unit for Physiological Chemistry, the Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 606-8501, Japan
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10
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Chen Y, Hu Q, Wang C, Wang T. The crosstalk between BAT thermogenesis and skeletal muscle dysfunction. Front Physiol 2023; 14:1132830. [PMID: 37153220 PMCID: PMC10160478 DOI: 10.3389/fphys.2023.1132830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 04/11/2023] [Indexed: 05/09/2023] Open
Abstract
Metabolic defects increase the risk of skeletal muscle diseases, and muscle impairment might worsen metabolic disruption, leading to a vicious cycle. Both brown adipose tissue (BAT) and skeletal muscle play important roles in non-shivering thermogenesis to regulate energy homeostasis. BAT regulates body temperature, systemic metabolism, and seretion of batokines that have positive or negative impacts on skeletal muscle. Conversely, muscle can secrete myokines that regulate BAT function. This review explained the crosstalk between BAT and skeletal muscle, and then discussed the batokines and highlighted their impact on skeletal muscle under physiological conditions. BAT is now considered a potential therapeutic target for obesity and diabetes treatment. Moreover, manipulation of BAT may be an attractive approach for the treatment of muscle weakness by correcting metabolic deficits. Therefore, exploring BAT as a potential treatment for sarcopenia could be a promising avenue for future research.
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Affiliation(s)
- Yao Chen
- Department of Breast Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Qian Hu
- Health Management Center, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Changyi Wang
- Department of Rehabilitation Medicine, Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Institute of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- *Correspondence: Changyi Wang, ; Tiantian Wang,
| | - Tiantian Wang
- Department of Rehabilitation Medicine, Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Institute of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- *Correspondence: Changyi Wang, ; Tiantian Wang,
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11
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Davis S, Hocking S, Watt MJ, Gunton JE. Metabolic effects of lipectomy and of adipose tissue transplantation. Obesity (Silver Spring) 2023; 31:7-19. [PMID: 36479639 PMCID: PMC10946570 DOI: 10.1002/oby.23601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 08/10/2022] [Accepted: 08/15/2022] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The goal of this study was to review the metabolic effects of fat transplantation. METHODS Fat (adipose tissue [AT]) transplantation has been performed extensively for many years in the cosmetic reconstruction industry. However, not all fats are equal. White, brown, and beige AT differ in energy storage and use. Brown and beige AT consume glucose and lipids for thermogenesis and, theoretically, may provide greater metabolic benefit in transplantation. Here, the authors review the metabolic effects of AT transplantation. RESULTS Removal of subcutaneous human AT does not have beneficial metabolic effects. Most studies find no benefit from visceral AT transplantation and some studies report harmful effects. In contrast, transplantation of inguinal or subcutaneous AT in mice has positive effects. Brown AT transplant studies have variable results depending on the model but most show benefit. CONCLUSIONS Many technical improvements have optimized fat grafting and transplantation in cosmetic surgery. Transplantation of subcutaneous AT has the potential for significant metabolic benefits, although there are few studies in humans or using human AT. Brown AT transplantation is beneficial but not readily feasible in humans thus ex vivo "beiging" may be a useful strategy. AT transplantation may provide clinical benefits in metabolic disorders, especially in the setting of lipodystrophy.
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Affiliation(s)
- Sarah Davis
- Centre for Diabetes, Obesity and Endocrinology ResearchThe Westmead Institute for Medical Research, The University of SydneySydneyNew South WalesAustralia
- Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
| | - Samantha Hocking
- Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
- Department of EndocrinologyRoyal Prince Alfred HospitalSydneyNew South WalesAustralia
| | - Matthew J. Watt
- Department of Anatomy and PhysiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Jenny E. Gunton
- Centre for Diabetes, Obesity and Endocrinology ResearchThe Westmead Institute for Medical Research, The University of SydneySydneyNew South WalesAustralia
- Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
- Department of Diabetes and EndocrinologyWestmead HospitalSydneyNew South WalesAustralia
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12
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Engelhard CA, Huang C, Khani S, Kasparek P, Prochazka J, Rozman J, Reguera DP, Sedlacek R, Kornfeld JW. Comprehensive Transcriptional Profiling and Mouse Phenotyping Reveals Dispensable Role for Adipose Tissue Selective Long Noncoding RNA Gm15551. Noncoding RNA 2022; 8:ncrna8030032. [PMID: 35645339 PMCID: PMC9149892 DOI: 10.3390/ncrna8030032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 12/20/2022] Open
Abstract
Cold and nutrient-activated brown adipose tissue (BAT) is capable of increasing systemic energy expenditure via the uncoupled respiration and secretion of endocrine factors, thereby protecting mice against diet-induced obesity and improving insulin response and glucose tolerance in men. Long non-coding RNAs (lncRNAs) have recently been identified as fine-tuning regulators of cellular function. While certain lncRNAs have been functionally characterised in adipose tissue, their overall contribution in the activation of BAT remains elusive. We identified lncRNAs correlating to interscapular brown adipose tissue (iBAT) function in a high fat diet (HFD) and cold stressed mice. We focused on Gm15551, which has an adipose tissue specific expression profile, is highly upregulated during adipogenesis, and downregulated by β-adrenergic activation in mature adipocytes. Although we performed comprehensive transcriptional and adipocyte physiology profiling in vitro and in vivo, we could not detect an effect of gain or loss of function of Gm15551.
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Affiliation(s)
- Christoph Andreas Engelhard
- Department for Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark; (C.A.E.); (C.H.)
| | - Chien Huang
- Department for Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark; (C.A.E.); (C.H.)
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Sajjad Khani
- Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Köln, Germany;
- Institute for Diabetes and Cancer (IDC), Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
- Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine, University Hospital of Cologne, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Petr Kasparek
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 25250 Vestec, Czech Republic; (P.K.); (J.P.); (J.R.); (D.P.R.); (R.S.)
| | - Jan Prochazka
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 25250 Vestec, Czech Republic; (P.K.); (J.P.); (J.R.); (D.P.R.); (R.S.)
| | - Jan Rozman
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 25250 Vestec, Czech Republic; (P.K.); (J.P.); (J.R.); (D.P.R.); (R.S.)
| | - David Pajuelo Reguera
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 25250 Vestec, Czech Republic; (P.K.); (J.P.); (J.R.); (D.P.R.); (R.S.)
| | - Radislav Sedlacek
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 25250 Vestec, Czech Republic; (P.K.); (J.P.); (J.R.); (D.P.R.); (R.S.)
| | - Jan-Wilhelm Kornfeld
- Department for Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark; (C.A.E.); (C.H.)
- Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Köln, Germany;
- Correspondence:
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13
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Torres Irizarry VC, Jiang Y, He Y, Xu P. Hypothalamic Estrogen Signaling and Adipose Tissue Metabolism in Energy Homeostasis. Front Endocrinol (Lausanne) 2022; 13:898139. [PMID: 35757435 PMCID: PMC9218066 DOI: 10.3389/fendo.2022.898139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/29/2022] [Indexed: 11/30/2022] Open
Abstract
Obesity has become a global epidemic, and it is a major risk factor for other metabolic disorders such as type 2 diabetes and cardiometabolic disease. Accumulating evidence indicates that there is sex-specific metabolic protection and disease susceptibility. For instance, in both clinical and experimental studies, males are more likely to develop obesity, insulin resistance, and diabetes. In line with this, males tend to have more visceral white adipose tissue (WAT) and less brown adipose tissue (BAT) thermogenic activity, both leading to an increased incidence of metabolic disorders. This female-specific fat distribution is partially mediated by sex hormone estrogens. Specifically, hypothalamic estrogen signaling plays a vital role in regulating WAT distribution, WAT beiging, and BAT thermogenesis. These regulatory effects on adipose tissue metabolism are primarily mediated by the activation of estrogen receptor alpha (ERα) in neurons, which interacts with hormones and adipokines such as leptin, ghrelin, and insulin. This review discusses the contribution of adipose tissue dysfunction to obesity and the role of hypothalamic estrogen signaling in preventing metabolic diseases with a particular focus on the VMH, the central regulator of energy expenditure and glucose homeostasis.
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Affiliation(s)
- Valeria C. Torres Irizarry
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, United States
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL, United States
| | - Yuwei Jiang
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, United States
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL, United States
- *Correspondence: Yuwei Jiang, ; Yanlin He, ; Pingwen Xu,
| | - Yanlin He
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, United States
- *Correspondence: Yuwei Jiang, ; Yanlin He, ; Pingwen Xu,
| | - Pingwen Xu
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, United States
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL, United States
- *Correspondence: Yuwei Jiang, ; Yanlin He, ; Pingwen Xu,
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14
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Manfredi LH. Overheating or overcooling: heat transfer in the spot to fight against the pandemic obesity. Rev Endocr Metab Disord 2021; 22:665-680. [PMID: 33000381 DOI: 10.1007/s11154-020-09596-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/17/2020] [Indexed: 12/25/2022]
Abstract
The prevalence of obesity has nearly doubled worldwide over the past three and a half decades, reaching pandemic status. Obesity is associated with decreased life expectancy and with an increased risk of metabolic, cardiovascular, nervous system diseases. Hence, understanding the mechanisms involved in the onset and development of obesity is mandatory to promote planned health actions to revert this scenario. In this review, common aspects of cold exposure, a process of heat generation, and exercise, a process of heat dissipation, will be discussed as two opposite mechanisms of obesity, which can be oversimplified as caloric conservation. A common road between heat generation and dissipation is the mobilization of Free Faty Acids (FFA) and Carbohydrates (CHO). An increase in energy expenditure (immediate effect) and molecular/metabolic adaptations (chronic effect) are responses that depend on SNS activity in both conditions of heat transfer. This cycle of using and removing FFA and CHO from blood either for heat or force generation disrupt the key concept of obesity: energy accumulation. Despite efforts in making the anti-obesity pill, maybe it is time to consider that the world's population is living at thermoneutrality since temperature-controlled places and the lack of exercise are favoring caloric accumulation.
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Affiliation(s)
- Leandro Henrique Manfredi
- Graduate Program in Biomedical Sciences, Federal University of Fronteira Sul, Chapecó, Santa Catarina, Brazil.
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15
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Tournissac M, Leclerc M, Valentin-Escalera J, Vandal M, Bosoi CR, Planel E, Calon F. Metabolic determinants of Alzheimer's disease: A focus on thermoregulation. Ageing Res Rev 2021; 72:101462. [PMID: 34534683 DOI: 10.1016/j.arr.2021.101462] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/09/2021] [Accepted: 09/11/2021] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is a complex age-related neurodegenerative disease, associated with central and peripheral metabolic anomalies, such as impaired glucose utilization and insulin resistance. These observations led to a considerable interest not only in lifestyle-related interventions, but also in repurposing insulin and other anti-diabetic drugs to prevent or treat dementia. Body temperature is the oldest known metabolic readout and mechanisms underlying its maintenance fail in the elderly, when the incidence of AD rises. This raises the possibility that an age-associated thermoregulatory deficit contributes to energy failure underlying AD pathogenesis. Brown adipose tissue (BAT) plays a central role in thermogenesis and maintenance of body temperature. In recent years, the modulation of BAT activity has been increasingly demonstrated to regulate energy expenditure, insulin sensitivity and glucose utilization, which could also provide benefits for AD. Here, we review the evidence linking thermoregulation, BAT and insulin-related metabolic defects with AD, and we propose mechanisms through which correcting thermoregulatory impairments could slow the progression and delay the onset of AD.
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16
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Cheng L, Wang J, Dai H, Duan Y, An Y, Shi L, Lv Y, Li H, Wang C, Ma Q, Li Y, Li P, Du H, Zhao B. Brown and beige adipose tissue: a novel therapeutic strategy for obesity and type 2 diabetes mellitus. Adipocyte 2021; 10:48-65. [PMID: 33403891 PMCID: PMC7801117 DOI: 10.1080/21623945.2020.1870060] [Citation(s) in RCA: 158] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mammalian adipose tissue can be divided into two major types, namely, white adipose tissue (WAT) and brown adipose tissue (BAT). According to classical view, the main function of WAT is to store excess energy in the form of triglycerides, while BAT is a thermogenic tissue that acts a pivotal part in maintaining the core body temperature. White adipocytes display high plasticity and can transdifferentiate into beige adipocytes which have many similar morphological and functional properties with brown adipocytes under the stimulations of exercise, cold exposure and other factors. This phenomenon is also known as 'browning of WAT'. In addition to transdifferentiation, beige adipocytes can also come from de novo differentiation from tissue-resident progenitors. Activating BAT and inducing browning of WAT can accelerate the intake of glycolipids and reduce the insulin secretion requirement, which may be a new strategy to improve glycolipids metabolism and insulin resistance of obese and type 2 diabetes mellitus (T2DM) patients. This review mainly discusses the significance of brown and beige adipose tissues in the treatment of obesity and T2DM, and focuses on the effect of the browning agent on obesity and T2DM, which provides a brand-new theoretical reference for the prevention and treatment of obesity and T2DM.
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Affiliation(s)
- Long Cheng
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Jingkang Wang
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Hongyu Dai
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Yuhui Duan
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Yongcheng An
- College of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Lu Shi
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Yinglan Lv
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Huimin Li
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Chen Wang
- College of Life Sciences, Beijing University of Chinese Medicine, Beijing, China
| | - Quantao Ma
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Yaqi Li
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Pengfei Li
- Department of Pharmacology, School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing China
| | - Haifeng Du
- The Third Municipal Hospital of Chengde, Chengde, China
| | - Baosheng Zhao
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing China
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17
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Claflin KE, Flippo KH, Sullivan AI, Naber MC, Zhou B, Neff TJ, Jensen-Cody SO, Potthoff MJ. Conditional gene targeting using UCP1-Cre mice directly targets the central nervous system beyond thermogenic adipose tissues. Mol Metab 2021; 55:101405. [PMID: 34844020 PMCID: PMC8683614 DOI: 10.1016/j.molmet.2021.101405] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/12/2022] Open
Abstract
Objective Uncoupling protein 1 (UCP1) is a mitochondrial protein critical for adaptive thermogenesis in adipose tissues, and it is typically believed to be restricted to thermogenic adipose tissues. UCP1-Cre transgenic mice are utilized in numerous studies to provide “brown adipose-specific” conditional gene targeting. Here, we examined the distribution of Cre and UCP1 throughout the body in UCP1-Cre reporter mice. Methods UCP1-Cre mice crossed to Ai14-tdTomato and Ai9-tdTomato reporter mice were used to explore the tissue distribution of Cre recombinase and Ucp1 mRNA in various tissues. UCP1-Cre mice were independently infected with either a Cre-dependent PHP.eB-tdTomato virus or a Cre-dependent AAV-tdTomato virus to determine whether and where UCP1 is actively expressed in the adult central nervous system. In situ analysis of the deposited single cell RNA sequencing data was used to evaluate Ucp1 expression in the hypothalamus. Results As expected, Ucp1 expression was detected in both brown and inguinal adipose tissues. Ucp1 expression was also detected in the kidney, adrenal glands, thymus, and hypothalamus. Consistent with detectable Ucp1 expression, tdTomato expression was also observed in brown adipose tissue, inguinal white adipose tissue, kidney, adrenal glands, and hypothalamus of both male and female UCP1-Cre; Ai14-tdTomato and UCP1-Cre; Ai9-tdTomato mice by fluorescent imaging and qPCR. Critically, expression of tdTomato, and thus UCP1, within the central nervous system was observed in regions of the brain critical for the regulation of energy homeostasis, including the ventromedial hypothalamus (VMH). Conclusions TdTomato expression in UCP1-Cre; tdTomato mice is not restricted to thermogenic adipose tissues. TdTomato was also expressed in the kidneys, adrenal glands, and throughout the brain, including brain regions and cell types that are critical for multiple aspects of central regulation of energy homeostasis. Collectively, these data have important implications for the utility of UCP1-Cre mice as genetic tools to investigate gene function specifically in brown adipose tissue. UCP1-Cre transgenic mice express Cre in tissues beyond thermogenic adipose tissues. UCP1-Cre; tdTomato reporter mice show that Cre is also expressed throughout the brain, kidney, and adrenal glands. Ucp1 mRNA is actively expressed in the central nervous system of adult mice.
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Affiliation(s)
- Kristin E Claflin
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Kyle H Flippo
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Andrew I Sullivan
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Meghan C Naber
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Bolu Zhou
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Tate J Neff
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Sharon O Jensen-Cody
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Matthew J Potthoff
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Veterans Affairs Medical Center, Iowa City, IA 52242, USA.
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18
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Gómez-Hernández A, de las Heras N, López-Pastor AR, García-Gómez G, Infante-Menéndez J, González-López P, González-Illanes T, Lahera V, Benito M, Escribano Ó. Severe Hepatic Insulin Resistance Induces Vascular Dysfunction: Improvement by Liver-Specific Insulin Receptor Isoform A Gene Therapy in a Murine Diabetic Model. Cells 2021; 10:cells10082035. [PMID: 34440804 PMCID: PMC8392327 DOI: 10.3390/cells10082035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 07/31/2021] [Accepted: 08/06/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Cardiovascular dysfunction is linked to insulin-resistant states. In this paper, we analyzed whether the severe hepatic insulin resistance of an inducible liver-specific insulin receptor knockout (iLIRKO) might generate vascular insulin resistance and dysfunction, and whether insulin receptor (IR) isoforms gene therapy might revert it. METHODS We studied in vivo insulin signaling in aorta artery and heart from iLIRKO. Vascular reactivity and the mRNA levels of genes involved in vascular dysfunction were analyzed in thoracic aorta rings by qRT-PCR. Finally, iLIRKO mice were treated with hepatic-specific gene therapy to analyze vascular dysfunction improvement. RESULTS Our results suggest that severe hepatic insulin resistance was expanded to cardiovascular tissues. This vascular insulin resistance observed in aorta artery from iLIRKO mice correlated with a reduction in both PI3K/AKT/eNOS and p42/44 MAPK pathways, and it might be implicated in their vascular alterations characterized by endothelial dysfunction, hypercontractility and eNOS/iNOS levels' imbalance. Finally, regarding long-term hepatic expression of IR isoforms, IRA was more efficient than IRB in the improvement of vascular dysfunction observed in iLIRKO mice. CONCLUSION Severe hepatic insulin resistance is sufficient to produce cardiovascular insulin resistance and dysfunction. Long-term hepatic expression of IRA restored the vascular damage observed in iLIRKO mice.
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Affiliation(s)
- Almudena Gómez-Hernández
- Laboratory of Hepatic and Cardiovascular Diseases, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.R.L.-P.); (J.I.-M.); (P.G.-L.); (T.G.-I.)
- Correspondence: (A.G.-H.); (Ó.E.)
| | - Natalia de las Heras
- Department of Physiology, School of Medicine, Complutense University of Madrid, 28040 Madrid, Spain; (N.d.l.H.); (V.L.)
| | - Andrea R. López-Pastor
- Laboratory of Hepatic and Cardiovascular Diseases, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.R.L.-P.); (J.I.-M.); (P.G.-L.); (T.G.-I.)
| | - Gema García-Gómez
- Laboratory of Diabetes and Obesity, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (G.G.-G.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Jorge Infante-Menéndez
- Laboratory of Hepatic and Cardiovascular Diseases, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.R.L.-P.); (J.I.-M.); (P.G.-L.); (T.G.-I.)
| | - Paula González-López
- Laboratory of Hepatic and Cardiovascular Diseases, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.R.L.-P.); (J.I.-M.); (P.G.-L.); (T.G.-I.)
| | - Tamara González-Illanes
- Laboratory of Hepatic and Cardiovascular Diseases, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.R.L.-P.); (J.I.-M.); (P.G.-L.); (T.G.-I.)
| | - Vicente Lahera
- Department of Physiology, School of Medicine, Complutense University of Madrid, 28040 Madrid, Spain; (N.d.l.H.); (V.L.)
| | - Manuel Benito
- Laboratory of Diabetes and Obesity, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (G.G.-G.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Óscar Escribano
- Laboratory of Hepatic and Cardiovascular Diseases, Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain; (A.R.L.-P.); (J.I.-M.); (P.G.-L.); (T.G.-I.)
- Correspondence: (A.G.-H.); (Ó.E.)
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Wang H, Wang M, Chansaenpak K, Liu Y, Yuan H, Xie J, Yin H, Branca RT, Li Z, Wu Z. A Novel PET Probe for Brown Adipose Tissue Imaging in Rodents. Mol Imaging Biol 2021; 22:675-684. [PMID: 31520279 DOI: 10.1007/s11307-019-01426-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE Brown adipose tissue (BAT) has emerged as a promising target to counteract obesity and its associated metabolic disorders. However, the detection of this tissue remains one of the major roadblocks. PROCEDURES In this study, we assess the use of BODIPY 1 as a positron emission tomography (PET) imaging agent to image BAT depots in vivo in two mouse phenotypes: obesity-resistant BALB/c mice and the obesity-prone C57BL/6 mice. [18F]BODIPY 1 is a radioactive dye that processed both radioactivity for PET imaging and fluorescence signal for in vitro mechanism study. RESULTS Through the co-staining of cancer cells with BODIPY 1 and MitoTracker, we found BODIPY 1 mainly accumulated in cell mitochondria in vitro. Fluorescence imaging of primary brown and white adipocytes further confirmed BODIPY 1 had significantly higher accumulation in primary brown adipocytes compared with primary white adipocytes. We evaluated [18F]BODIPY 1 for BAT imaging in both obesity-resistant BALB/c mice and obesity-prone C57BL/6 mice. Indeed, [18F]BODIPY 1 was efficiently taken up by BAT in both mouse genotypes (6.40 ± 1.98 %ID/g in obesity-resistant BALB/c mice (n = 8) and 5.37 ± 0.82 %ID/g in obesity-prone C57BL/6 mice (n = 7)). Although norepinephrine stimulation could increase the absolute BAT uptake, the enhancement is not significant in both genotypes (p > 0.05) at current sample size. These results suggest BAT uptake of [18F]BODIPY 1 may be independent of BAT thermogenic activity. As a comparison, 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) PET imaging was performed in obesity-resistant BALB/c mice. Significantly increased uptake was observed in adrenergically activated BAT (10.08 ± 2.52 %ID/g, n = 3) but not in inactive BAT (3.803 ± 0.70 %ID/g; n = 3). Because [18F]BODIPY 1 maintained its fluorescent property, BAT tissue was excised and studied using fluorescence microscopy. Strong fluorescence signal was observed in BAT mouse that was injected with BODIPY 1. CONCLUSIONS Unlike [18F]FDG, [18F]BODIPY 1 showed prominent accumulation in BAT under both inactive and stimulated status. [18F]BODIPY 1 may serve as a valuable BAT PET agent to possibly assess BAT mitochondria density, thus BAT thermogenic capacity after further evaluation.
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Affiliation(s)
- Hui Wang
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Mengzhe Wang
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Kantapat Chansaenpak
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Yang Liu
- Center for Molecular Medicine, Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
| | - Hong Yuan
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jin Xie
- Department of Chemistry, Bio-Imaging Research Center, The University of Georgia, Athens, GA, 30602, USA
| | - Hang Yin
- Center for Molecular Medicine, Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, 30602, USA
| | - Rosa T Branca
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Zibo Li
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Zhanhong Wu
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA. .,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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20
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Cohen P, Kajimura S. The cellular and functional complexity of thermogenic fat. Nat Rev Mol Cell Biol 2021; 22:393-409. [PMID: 33758402 PMCID: PMC8159882 DOI: 10.1038/s41580-021-00350-0] [Citation(s) in RCA: 192] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2021] [Indexed: 02/01/2023]
Abstract
Brown and beige adipocytes are mitochondria-enriched cells capable of dissipating energy in the form of heat. These thermogenic fat cells were originally considered to function solely in heat generation through the action of the mitochondrial protein uncoupling protein 1 (UCP1). In recent years, significant advances have been made in our understanding of the ontogeny, bioenergetics and physiological functions of thermogenic fat. Distinct subtypes of thermogenic adipocytes have been identified with unique developmental origins, which have been increasingly dissected in cellular and molecular detail. Moreover, several UCP1-independent thermogenic mechanisms have been described, expanding the role of these cells in energy homeostasis. Recent studies have also delineated roles for these cells beyond the regulation of thermogenesis, including as dynamic secretory cells and as a metabolic sink. This Review presents our current understanding of thermogenic adipocytes with an emphasis on their development, biological functions and roles in systemic physiology.
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Affiliation(s)
- Paul Cohen
- Laboratory of Molecular Metabolism, The Rockefeller University, New York, NY, USA.
| | - Shingo Kajimura
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
- Department of Cell and Tissue Biology, UCSF Diabetes Center, University of California, San Francisco, San Francisco, CA, USA.
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21
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Abstract
Obesity, an excess accumulation of white adipose tissue (WAT), has become a global epidemic and is associated with complex diseases, such as type 2 diabetes and cardiovascular diseases. Presently, there are no safe and effective therapeutic agents to treat obesity. In contrast to white adipocytes that store energy as triglycerides in unilocular lipid droplet, brown and brown-like or beige adipocytes utilize fatty acids (FAs) and glucose at a high rate mainly by uncoupling protein 1 (UCP1) action to uncouple mitochondrial proton gradient from ATP synthesis, dissipating energy as heat. Recent studies on the presence of brown or brown-like adipocytes in adult humans have revealed their potential as therapeutic targets in combating obesity. Classically, the main signaling pathway known to activate thermogenesis in adipocytes is β3-adrenergic signaling, which is activated by norepinephrine in response to cold, leading to activation of the thermogenic program and browning. In addition to the β3-adrenergic signaling, numerous other hormones and secreted factors have been reported to affect thermogenesis. In this review, we discuss several major pathways, β3-adrenergic, insulin/IGF1, thyroid hormone and TGFβ family, which regulate thermogenesis and browning of WAT.
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Affiliation(s)
| | - Hei Sook Sul
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, United States
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22
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Rodríguez-Rivera C, Santín Moreda L, Alguacil LF, Escrivá F, Álvarez C, González-Martín C. Undernutrition induces major alterations in the lipid droplets of white and brown adipose tissues in wistar rats. Tissue Cell 2021; 71:101500. [PMID: 33640739 DOI: 10.1016/j.tice.2021.101500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 11/15/2022]
Abstract
Several studies have shown a relationship between the distribution of fat mass around the organism, metabolic disorders, and an increased risk of morbidity and mortality. It has been demonstrated that in obese animals there is a big rise in the white fat deposits due to hyperplasia and hypertrophy of the adipocytes. Studies related to weight and health have been more popular regarding obesity rather than extreme caquexia or calorico-proteic deficiencies, but these states are interesting from the point of view of the preferential atrophy of certain organs that may help us in the understanding of undernourishment. Moreover, the discovery of beige adipose tissue has instigated thoughts around the roles played by the different cells in the adipose tissue as well as its adaptability in pathological states. In our study we carried out morphometric, morphological, and quantitative measurements of the adipose tissue in an animal model based on a 40-50% diet restriction in comparison to control animals. We have found a decrease in the size of white adipocytes together with a variation in the lipid droplet size of brown adipocytes in undernourished animals, what may be considered as possible transformations between the types of adipose tissues, and that could be caused by an adaptive phenomenon to the undernourished state.
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Affiliation(s)
| | | | - Luis F Alguacil
- University CEU San Pablo, Faculty of Pharmacy, Madrid, Spain
| | - Fernando Escrivá
- University Complutense de Madrid, Faculty of Pharmacy, Madrid, Spain
| | - Carmen Álvarez
- University Complutense de Madrid, Faculty of Pharmacy, Madrid, Spain
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23
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Wang X, Zhao Y, Zhou D, Tian Y, Feng G, Lu Z. Gab2 deficiency suppresses high-fat diet-induced obesity by reducing adipose tissue inflammation and increasing brown adipose function in mice. Cell Death Dis 2021; 12:212. [PMID: 33637697 PMCID: PMC7910586 DOI: 10.1038/s41419-021-03519-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/07/2021] [Accepted: 02/09/2021] [Indexed: 12/13/2022]
Abstract
Obesity is caused by a long-term imbalance between energy intake and consumption and is regulated by multiple signals. This study investigated the effect of signaling scaffolding protein Gab2 on obesity and its relevant regulation mechanism. Gab2 knockout (KO) and wild-type (WT) mice were fed with a standard diet (SD) or high-fat diet (HFD) for 12 weeks. The results showed that the a high-fat diet-induced Gab2 expression in adipose tissues, but deletion of Gab2 attenuated weight gain and improved glucose tolerance in mice fed with a high-fat diet. White adipose tissue and systemic inflammations were reduced in HFD-fed Gab2 deficiency mice. Gab2 deficiency increased the expression of Ucp1 and other thermogenic genes in brown adipose tissue. Furthermore, the regulation of Gab2 on the mature differentiation and function of adipocytes was investigated in vitro using primary or immortalized brown preadipocytes. The expression of brown fat-selective genes was found to be elevated in differentiated adipocytes without Gab2. The mechanism of Gab2 regulating Ucp1 expression in brown adipocytes involved with its downstream PI3K (p85)-Akt-FoxO1 signaling pathway. Our research suggests that deletion of Gab2 suppresses diet-induced obesity by multiple pathways and Gab2 may be a novel therapeutic target for the treatment of obesity and associated complications.
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MESH Headings
- Adaptor Proteins, Signal Transducing/deficiency
- Adaptor Proteins, Signal Transducing/genetics
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/physiopathology
- Adipose Tissue, White/metabolism
- Adipose Tissue, White/physiopathology
- Adiposity
- Animals
- Blood Glucose/metabolism
- Cell Line
- Class Ia Phosphatidylinositol 3-Kinase/metabolism
- Diet, High-Fat
- Disease Models, Animal
- Energy Metabolism
- Forkhead Box Protein O1/metabolism
- Insulin Resistance
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Obesity/genetics
- Obesity/metabolism
- Obesity/physiopathology
- Obesity/prevention & control
- Panniculitis/genetics
- Panniculitis/metabolism
- Panniculitis/physiopathology
- Panniculitis/prevention & control
- Proto-Oncogene Proteins c-akt/metabolism
- Signal Transduction
- Uncoupling Protein 1/metabolism
- Weight Gain
- Mice
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Affiliation(s)
- Xinhui Wang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, 361005, Xiamen, Fujian, China
| | - Yinan Zhao
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, 361005, Xiamen, Fujian, China
| | - Dekun Zhou
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, 361005, Xiamen, Fujian, China
| | - Yingpu Tian
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, 361005, Xiamen, Fujian, China
| | - Gensheng Feng
- Department of Pathology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Zhongxian Lu
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, 361005, Xiamen, Fujian, China.
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24
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Brown Adipose Tissue and Its Role in Insulin and Glucose Homeostasis. Int J Mol Sci 2021; 22:ijms22041530. [PMID: 33546400 PMCID: PMC7913527 DOI: 10.3390/ijms22041530] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/21/2021] [Accepted: 02/01/2021] [Indexed: 12/15/2022] Open
Abstract
The increased worldwide prevalence of obesity, insulin resistance, and their related metabolic complications have prompted the scientific world to search for new possibilities to combat obesity. Brown adipose tissue (BAT), due to its unique protein uncoupling protein 1 (UPC1) in the inner membrane of the mitochondria, has been acknowledged as a promising approach to increase energy expenditure. Activated brown adipocytes dissipate energy, resulting in heat production. In other words, BAT burns fat and increases the metabolic rate, promoting a negative energy balance. Moreover, BAT alleviates metabolic complications like dyslipidemia, impaired insulin secretion, and insulin resistance in type 2 diabetes. The aim of this review is to explore the role of BAT in total energy expenditure, as well as lipid and glucose homeostasis, and to discuss new possible activators of brown adipose tissue in humans to treat obesity and metabolic disorders.
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25
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Molecular Mechanisms of Glucocorticoid-Induced Insulin Resistance. Int J Mol Sci 2021; 22:ijms22020623. [PMID: 33435513 PMCID: PMC7827500 DOI: 10.3390/ijms22020623] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/29/2020] [Accepted: 01/02/2021] [Indexed: 12/12/2022] Open
Abstract
Glucocorticoids (GCs) are steroids secreted by the adrenal cortex under the hypothalamic-pituitary-adrenal axis control, one of the major neuro-endocrine systems of the organism. These hormones are involved in tissue repair, immune stability, and metabolic processes, such as the regulation of carbohydrate, lipid, and protein metabolism. Globally, GCs are presented as ‘flight and fight’ hormones and, in that purpose, they are catabolic hormones required to mobilize storage to provide energy for the organism. If acute GC secretion allows fast metabolic adaptations to respond to danger, stress, or metabolic imbalance, long-term GC exposure arising from treatment or Cushing’s syndrome, progressively leads to insulin resistance and, in fine, cardiometabolic disorders. In this review, we briefly summarize the pharmacological actions of GC and metabolic dysregulations observed in patients exposed to an excess of GCs. Next, we describe in detail the molecular mechanisms underlying GC-induced insulin resistance in adipose tissue, liver, muscle, and to a lesser extent in gut, bone, and brain, mainly identified by numerous studies performed in animal models. Finally, we present the paradoxical effects of GCs on beta cell mass and insulin secretion by the pancreas with a specific focus on the direct and indirect (through insulin-sensitive organs) effects of GCs. Overall, a better knowledge of the specific action of GCs on several organs and their molecular targets may help foster the understanding of GCs’ side effects and design new drugs that possess therapeutic benefits without metabolic adverse effects.
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Catestatin peptide of chromogranin A as a potential new target for several risk factors management in the course of metabolic syndrome. Biomed Pharmacother 2020; 134:111113. [PMID: 33341043 DOI: 10.1016/j.biopha.2020.111113] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/29/2020] [Accepted: 12/04/2020] [Indexed: 12/12/2022] Open
Abstract
Obesity, lipodystrophy, diabetes, and hypertension collectively constitute the main features of Metabolic Syndrome (MetS), together with insulin resistance (IR), which is considered as a defining element. MetS generally leads to the development of cardiovascular disease (CVD), which is a determinant cause of mortality and morbidity in humans and animals. Therefore, it is essential to implement and put in place adequate management strategies for the treatment of this disease. Catestatin is a bioactive peptide with 21 amino acids, which is derived through cleaving of the prohormone chromogranin A (CHGA/CgA) that is co-released with catecholamines from secretory vesicles and, which is responsible for hepatic/plasma lipids and insulin levels regulation, improves insulin sensitivity, reduces hypertension and attenuates obesity in murine models. In humans, there were few published studies, which showed that low levels of catestatin are significant risk factors for hypertension in adult patients. These accumulating evidence documents clearly that catestatin peptide (CST) is linked to inflammatory and metabolic syndrome diseases and can be a novel regulator of insulin and lipid levels, blood pressure, and cardiac function. The goal of this review is to provide an overview of the CST effects in metabolic syndrome given its role in metabolic regulation and thus, provide new insights into the use of CST as a diagnostic marker and therapeutic target.
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27
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Diwekar-Joshi M, Watve M. Driver versus navigator causation in biology: the case of insulin and fasting glucose. PeerJ 2020; 8:e10396. [PMID: 33365205 PMCID: PMC7735078 DOI: 10.7717/peerj.10396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/29/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND In biomedicine, inferring causal relation from experimental intervention or perturbation is believed to be a more reliable approach than inferring causation from cross-sectional correlation. However, we point out here that even in interventional inference there are logical traps. In homeostatic systems, causality in a steady state can be qualitatively different from that in a perturbed state. On a broader scale there is a need to differentiate driver causality from navigator causality. A driver is essential for reaching a destination but may not have any role in deciding the destination. A navigator on the other hand has a role in deciding the destination and the path but may not be able to drive the system to the destination. The failure to differentiate between types of causalities is likely to have resulted into many misinterpretations in physiology and biomedicine. METHODS We illustrate this by critically re-examining a specific case of the causal role of insulin in glucose homeostasis using five different approaches (1) Systematic review of tissue specific insulin receptor knock-outs, (2) Systematic review of insulin suppression and insulin enhancement experiments, (3) Differentiating steady state and post-meal state glucose levels in streptozotocin treated rats in primary experiments, (4) Mathematical and theoretical considerations and (5) Glucose-insulin relationship in human epidemiological data. RESULTS All the approaches converge on the inference that although insulin action hastens the return to a steady state after a glucose load, there is no evidence that insulin action determines the steady state level of glucose. Insulin, unlike the popular belief in medicine, appears to be a driver but not a navigator for steady state glucose level. It is quite likely therefore that the current line of clinical action in the field of type 2 diabetes has limited success largely because it is based on a misinterpretation of glucose-insulin relationship. The insulin-glucose example suggests that we may have to carefully re-examine causal inferences from perturbation experiments and set up revised norms for experimental design for causal inference.
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Affiliation(s)
- Manawa Diwekar-Joshi
- Biology, Indian Institute of Science Education and Research, Pune, Maharashtra, India
| | - Milind Watve
- Deenanath Mangeshkar Hospital and Research Centre, Pune, Maharashtra, India
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Meep, a Novel Regulator of Insulin Signaling, Supports Development and Insulin Sensitivity via Maintenance of Protein Homeostasis in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2020; 10:4399-4410. [PMID: 32998936 PMCID: PMC7718763 DOI: 10.1534/g3.120.401688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Insulin signaling is critical for developmental growth and adult homeostasis, yet the downstream regulators of this signaling pathway are not completely understood. Using the model organism Drosophila melanogaster, we took a genomic approach to identify novel mediators of insulin signaling. These studies led to the identification of Meep, encoded by the gene CG32335. Expression of this gene is both insulin receptor- and diet-dependent. We found that Meep was specifically required in the developing fat body to tolerate a high-sugar diet (HSD). Meep is not essential on a control diet, but when reared on an HSD, knockdown of meep causes hyperglycemia, reduced growth, developmental delay, pupal lethality, and reduced longevity. These phenotypes stem in part from Meep’s role in promoting insulin sensitivity and protein stability. This work suggests a critical role for protein homeostasis in development during overnutrition. Because Meep is conserved and obesity-associated in mammals, future studies on Meep may help to understand the role of proteostasis in insulin-resistant type 2 diabetes.
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Chen M, Xu J, Wang Y, Wang Z, Guo L, Li X, Huang L. Arctium lappa L. polysaccharide can regulate lipid metabolism in type 2 diabetic rats through the SREBP-1/SCD-1 axis. Carbohydr Res 2020; 494:108055. [DOI: 10.1016/j.carres.2020.108055] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/13/2020] [Accepted: 05/29/2020] [Indexed: 12/12/2022]
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30
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Man XF, Hu N, Tan SW, Tang HN, Guo Y, Tang CY, Liu YQ, Tang J, Zhou CL, Wang F, Zhou HD. Insulin receptor substrate-1 inhibits high-fat diet-induced obesity by browning of white adipose tissue through miR-503. FASEB J 2020; 34:12308-12323. [PMID: 32721050 DOI: 10.1096/fj.201903283rr] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 06/13/2020] [Accepted: 07/01/2020] [Indexed: 12/18/2022]
Abstract
Genetic variation of insulin receptor substrate 1 (IRS-1) was found to modulate the insulin resistance of adipose tissues, but the underlying mechanism was not clear. To investigate how the IRS-1 was involved in the browning of white adipose tissue through miRNA, we identified a mutated Irs-1 (Irs-1-/- ) mice model and found that this mice had a reduced subcutaneous WAT (sWAT) and increased brown adipose tissue (BAT) in the interscapular region. So we isolated the bone marrow stromal cells and analyzed differentially expressed miRNAs and adipogenesis-related genes with miRNA arrays and PCR arrays. Irs-1-/- mice showed decreased miR-503 expression, but increased expression of its target, bone morphogenetic protein receptor type 1a (BMPR1a). Overexpression of miR-503 in preadipocytes downregulated BMPR1a and impaired adipogenic activity through the phosphotidylinositol 3-kinase (PI3K/Akt) pathway, while the inhibitor had the opposite effect. In both Irs-1-/- and cold-induced models, sWAT exhibited BAT features, and showed tissue-specific increased BMPR1a expression, PI3K expression, and Akt phosphorylation. Thus, our results showed that IRS-1 regulated brown preadipocyte differentiation and induced browning in sWAT through the miR-503-BMPR1a pathway, which played important roles in high-fat diet-induced obesity.
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Affiliation(s)
- Xiao-Fei Man
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Nan Hu
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Shu-Wen Tan
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hao-Neng Tang
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yue Guo
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Chen-Yi Tang
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Ya-Qing Liu
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jun Tang
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Ci-La Zhou
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Fang Wang
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hou-De Zhou
- Hunan Provincial Key Laboratory For Metabolic Bone Diseases, Department of Endocrinology and Metabolism, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, China
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31
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Targeting perivascular and epicardial adipose tissue inflammation: therapeutic opportunities for cardiovascular disease. Clin Sci (Lond) 2020; 134:827-851. [PMID: 32271386 DOI: 10.1042/cs20190227] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 03/20/2020] [Accepted: 03/30/2020] [Indexed: 02/07/2023]
Abstract
Major shifts in human lifestyle and dietary habits toward sedentary behavior and refined food intake triggered steep increase in the incidence of metabolic disorders including obesity and Type 2 diabetes. Patients with metabolic disease are at a high risk of cardiovascular complications ranging from microvascular dysfunction to cardiometabolic syndromes including heart failure. Despite significant advances in the standards of care for obese and diabetic patients, current therapeutic approaches are not always successful in averting the accompanying cardiovascular deterioration. There is a strong relationship between adipose inflammation seen in metabolic disorders and detrimental changes in cardiovascular structure and function. The particular importance of epicardial and perivascular adipose pools emerged as main modulators of the physiology or pathology of heart and blood vessels. Here, we review the peculiarities of these two fat depots in terms of their origin, function, and pathological changes during metabolic deterioration. We highlight the rationale for pharmacological targeting of the perivascular and epicardial adipose tissue or associated signaling pathways as potential disease modifying approaches in cardiometabolic syndromes.
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32
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Czech MP. Mechanisms of insulin resistance related to white, beige, and brown adipocytes. Mol Metab 2020; 34:27-42. [PMID: 32180558 PMCID: PMC6997501 DOI: 10.1016/j.molmet.2019.12.014] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/21/2019] [Accepted: 12/23/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The diminished glucose lowering effect of insulin in obesity, called "insulin resistance," is associated with glucose intolerance, type 2 diabetes, and other serious maladies. Many publications on this topic have suggested numerous hypotheses on the molecular and cellular disruptions that contribute to the syndrome. However, significant uncertainty remains on the mechanisms of its initiation and long-term maintenance. SCOPE OF REVIEW To simplify insulin resistance analysis, this review focuses on the unifying concept that adipose tissue is a central regulator of systemic glucose homeostasis by controlling liver and skeletal muscle metabolism. Key aspects of adipose function related to insulin resistance reviewed are: 1) the modes by which specific adipose tissues control hepatic glucose output and systemic glucose disposal, 2) recently acquired understanding of the underlying mechanisms of these modes of regulation, and 3) the steps in these pathways adversely affected by obesity that cause insulin resistance. MAJOR CONCLUSIONS Adipocyte heterogeneity is required to mediate the multiple pathways that control systemic glucose tolerance. White adipocytes specialize in sequestering triglycerides away from the liver, muscle, and other tissues to limit toxicity. In contrast, brown/beige adipocytes are very active in directly taking up glucose in response to β adrenergic signaling and insulin and enhancing energy expenditure. Nonetheless, white, beige, and brown adipocytes all share the common feature of secreting factors and possibly exosomes that act on distant tissues to control glucose homeostasis. Obesity exerts deleterious effects on each of these adipocyte functions to cause insulin resistance.
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Affiliation(s)
- Michael P Czech
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
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33
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Gu J, Wang X, Yang H, Li H, Wang J. Preclinical in vivo imaging for brown adipose tissue. Life Sci 2020; 249:117500. [PMID: 32147430 DOI: 10.1016/j.lfs.2020.117500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/23/2020] [Accepted: 03/02/2020] [Indexed: 12/22/2022]
Abstract
Brown adipose tissue (BAT) has multiple functions in the human body, including the production of heat and increasing energy consumption. However, BAT is also related to many kinds of diseases, such as obesity and metabolic disorders. The progression of such diseases occurs at the cellular level, and thus, imaging techniques could prove greatly beneficial for determining optimal therapeutic regimens. Currently, positron-emission tomography (PET) is considered to be the gold standard for assessing the function of activated BAT. However, PET also has inherent disadvantages, and, thus, recent efforts have been focused on exploring, and potentially developing, new imaging techniques to better observe BAT and evaluate its metabolic function. Researchers have already achieved promising success with computed tomography, magnetic resonance approaches, ultrasound, new tracers for use in PET, and other imaging techniques through in vivo and in vitro animal experiments. Since, these studies have shown that BAT may serve as an effective therapeutic target for treatment of metabolic dysfunction diseases, the development of an efficient in vivo BAT imaging technique that is applicable to humans will prove to be of great clinical value. In this review, classical PET imaging technique is highlighted as well as the current status of preclinical imaging methods developed for BAT examination.
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Affiliation(s)
- Jiaojiao Gu
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
| | - Xinlu Wang
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China.
| | - Hua Yang
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
| | - He Li
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
| | - Jie Wang
- Department of Ultrasound, Shengjing Hospital of China Medical University, Shengjing Hospital, No. 36, Sanhao Street, Heping District, Shenyang, Liaoning, China
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34
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González-García I, Milbank E, Martinez-Ordoñez A, Diéguez C, López M, Contreras C. HYPOTHesizing about central comBAT against obesity. J Physiol Biochem 2019; 76:193-211. [PMID: 31845114 DOI: 10.1007/s13105-019-00719-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 12/02/2019] [Indexed: 12/12/2022]
Abstract
The hypothalamus is a brain region in charge of many vital functions. Among them, BAT thermogenesis represents an essential physiological function to maintain body temperature. In the metabolic context, it has now been established that energy expenditure attributed to BAT function can contribute to the energy balance in a substantial extent. Thus, therapeutic interest in this regard has increased in the last years and some studies have shown that BAT function in humans can make a real contribution to improve diabetes and obesity-associated diseases. Nevertheless, how the hypothalamus controls BAT activity is still not fully understood. Despite the fact that much has been known about the mechanisms that regulate BAT activity in recent years, and that the central regulation of thermogenesis offers a very promising target, many questions remain still unsolved. Among them, the possible human application of knowledge obtained from rodent studies, and drug administration strategies able to specifically target the hypothalamus. Here, we review the current knowledge of homeostatic regulation of BAT, including the molecular insights of brown adipocytes, its central control, and its implication in the development of obesity.
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Affiliation(s)
- Ismael González-García
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.
| | - Edward Milbank
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Anxo Martinez-Ordoñez
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
| | - Carlos Diéguez
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Miguel López
- CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Cristina Contreras
- Department of Physiology, Pharmacy School, Complutense University of Madrid, 28040, Madrid, Spain.
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35
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Elkhatib MAW, Mroueh A, Rafeh RW, Sleiman F, Fouad H, Saad EI, Fouda MA, Elgaddar O, Issa K, Eid AH, Eid AA, Abd-Elrahman KS, El-Yazbi AF. Amelioration of perivascular adipose inflammation reverses vascular dysfunction in a model of nonobese prediabetic metabolic challenge: potential role of antidiabetic drugs. Transl Res 2019; 214:121-143. [PMID: 31408626 DOI: 10.1016/j.trsl.2019.07.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/28/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022]
Abstract
The onset of vascular impairment precedes that of diagnostic hyperglycemia in diabetic patients suggesting a vascular insult early in the course of metabolic dysfunction without a well-defined mechanism. Mounting evidence implicates adipose inflammation in the pathogenesis of insulin resistance and diabetes. It is not certain whether amelioration of adipose inflammation is sufficient to preclude vascular dysfunction in early stages of metabolic disease. Recent findings suggest that antidiabetic drugs, metformin, and pioglitazone, improve vascular function in prediabetic patients, without an indication if this protective effect is mediated by reduction of adipose inflammation. Here, we used a prediabetic rat model with delayed development of hyperglycemia to study the effect of metformin or pioglitazone on adipose inflammation and vascular function. At the end of the metabolic challenge, these rats were neither obese, hypertensive, nor hyperglycemic. However, they showed increased pressor responses to phenylephrine and augmented aortic and mesenteric contraction. Vascular tissues from prediabetic rats showed increased Rho-associated kinase activity causing enhanced calcium sensitization. An elevated level of reactive oxygen species was seen in aortic tissues together with increased Transforming growth factor β1 and Interleukin-1β expression. Although, no signs of systemic inflammation were detected, perivascular adipose inflammation was observed. Adipocyte hypertrophy, increased macrophage infiltration, and elevated Transforming growth factor β1 and Interleukin-1β mRNA levels were seen. Two-week treatment with metformin or pioglitazone or switching to normal chow ameliorated adipose inflammation and vascular dysfunction. Localized perivascular adipose inflammation is sufficient to trigger vascular dysfunction early in the course of diabetes. Interfering with this inflammatory process reverses this early abnormality.
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Affiliation(s)
- Mohammed A W Elkhatib
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Ali Mroueh
- Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut, Lebanon
| | - Rim W Rafeh
- Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut, Lebanon
| | - Fatima Sleiman
- Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut, Lebanon
| | - Hosny Fouad
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Evan I Saad
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Mohamed A Fouda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Ola Elgaddar
- Department of Chemical Pathology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Khodr Issa
- Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut, Lebanon
| | - Ali H Eid
- Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut, Lebanon; Department of Biomedical Sciences, Qatar University, Doha, Qatar
| | - Assaad A Eid
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, The American University of Beirut, Beirut, Lebanon
| | - Khaled S Abd-Elrahman
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa Brain and Mind Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Ahmed F El-Yazbi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt; Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut, Lebanon.
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36
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Khor NWM, Swarbrick MM, Gunton JE. Inducible UCP1 silencing: A lentiviral RNA-interference approach to quantify the contribution of beige fat to energy homeostasis. PLoS One 2019; 14:e0223987. [PMID: 31751350 PMCID: PMC6872148 DOI: 10.1371/journal.pone.0223987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/02/2019] [Indexed: 11/17/2022] Open
Abstract
Energy consuming, heat-producing beige adipocytes, located in classic white adipose tissue (WAT), hold promise for the treatment of obesity. Few reports have quantitatively assessed the contribution of browned 'WAT' to energy expenditure. There is a need for methods to examine beige-fat thermogenesis, independently of classical brown fat. The aim of this study is to optimize an inducible lentiviral shRNA to conditionally knock-down Ucp1 and assess the effects on 'browned' WAT. Primary adipocytes from mouse inguinal WAT converted into thermogenic adipocytes when stimulated with β-adrenergic agonist and thiazolidinedione. There was increased UCP1 protein and importantly increases in various indicators of mitochondrial bioenergetics. Next, we determined optimal transfection conditions for the UCP1-shRNA lentiviral system and subsequently applied this to 'browned' WAT. UCP1 knockdown decreased the brown/beige-fat gene profile and decreased mitochondrial respiration. In summary, this study optimizes lentiviral UCP1-shRNA technology in vitro. This technique could be applied to inguinal fat depots in vivo. This would allow investigation of contribution of depots to whole-body metabolism to help elucidate the physiological relevance of beige fat.
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Affiliation(s)
- Nicole Wen Mun Khor
- The Westmead Institute for Medical Research, Westmead, Sydney, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia.,Faculty of Medicine, University of New South Wales, Sydney, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Michael M Swarbrick
- The Westmead Institute for Medical Research, Westmead, Sydney, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia.,Faculty of Medicine, University of New South Wales, Sydney, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Jenny E Gunton
- The Westmead Institute for Medical Research, Westmead, Sydney, Australia.,Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia.,Faculty of Medicine, University of New South Wales, Sydney, Australia.,Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
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37
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Gomez-Hernandez A, Lopez-Pastor AR, Rubio-Longas C, Majewski P, Beneit N, Viana-Huete V, García-Gómez G, Fernandez S, Hribal ML, Sesti G, Escribano O, Benito M. Specific knockout of p85α in brown adipose tissue induces resistance to high-fat diet-induced obesity and its metabolic complications in male mice. Mol Metab 2019; 31:1-13. [PMID: 31918912 PMCID: PMC6977168 DOI: 10.1016/j.molmet.2019.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/14/2019] [Accepted: 10/30/2019] [Indexed: 12/19/2022] Open
Abstract
Objective An increase in mass and/or brown adipose tissue (BAT) functionality leads to an increase in energy expenditure, which may be beneficial for the prevention and treatment of obesity. Moreover, distinct class I PI3K isoforms can participate in metabolic control as well as in systemic dysfunctions associated with obesity. In this regard, we analyzed in vivo whether the lack of p85α in BAT (BATp85αKO) could modulate the activity and insulin signaling of this tissue, thereby improving diet-induced obesity and its associated metabolic complications. Methods We generated BATp85αKO mice using Cre-LoxP technology, specifically deleting p85α in a conditional manner. To characterize this new mouse model, we used mice of 6 and 12 months of age. In addition, BATp85αKO mice were submitted to a high-fat diet (HFD) to challenge BAT functionality. Results Our results suggest that the loss of p85α in BAT improves its thermogenic functionality, high-fat diet–induced adiposity and body weight, insulin resistance, and liver steatosis. The potential mechanisms involved in the improvement of obesity include (1) increased insulin signaling and lower activation of JNK in BAT, (2) enhanced insulin receptor isoform B (IRB) expression and association with IRS-1 in BAT, (3) lower production of proinflammatory cytokines by the adipose organ, (4) increased iWAT browning, and (5) improved liver steatosis. Conclusions Our results provide new mechanisms involved in the resistance to obesity development, supporting the hypothesis that the gain of BAT activity induced by the lack of p85α has a direct impact on the prevention of diet-induced obesity and its associated metabolic complications. The lack of p85α in brown adipose tissue confers obesity resistance. BATp85αKO mice show improved thermogenic function, fatty liver and insulin resistance. High IRB levels in BAT and iWAT browning might explain the improvement of obesity. Increase in BAT functionality has a direct impact on the prevention of obesity.
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Affiliation(s)
- Almudena Gomez-Hernandez
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain; Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain; CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Spain.
| | - Andrea R Lopez-Pastor
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain; Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain.
| | - Carlota Rubio-Longas
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain.
| | - Patrik Majewski
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain.
| | - Nuria Beneit
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain; Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain.
| | - Vanesa Viana-Huete
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain; Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain.
| | - Gema García-Gómez
- Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain; CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Spain.
| | - Silvia Fernandez
- Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain; CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Spain.
| | - Marta Letizia Hribal
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Italy.
| | - Giorgio Sesti
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Italy.
| | - Oscar Escribano
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain; Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain; CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Spain.
| | - Manuel Benito
- Biochemistry and Molecular Biology Department, School of Pharmacy, Complutense University of Madrid, Spain; Health Research Institute of San Carlos Clinic Hospital (IdISSC), Madrid, Spain; CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Spain.
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38
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mTOR signaling in Brown and Beige adipocytes: implications for thermogenesis and obesity. Nutr Metab (Lond) 2019; 16:74. [PMID: 31708995 PMCID: PMC6836431 DOI: 10.1186/s12986-019-0404-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 10/22/2019] [Indexed: 12/18/2022] Open
Abstract
Brown and beige adipocytes are mainly responsible for nonshivering thermogenesis or heat production, despite the fact that they have distinguished features in distribution, developmental origin, and functional activation. As a nutrient sensor and critical regulator of energy metabolism, mechanistic target of rapamycin (mTOR) also plays an important role in the development and functional maintenance of adipocytes. While the recent studies support the notion that mTOR (mTORC1 and mTORC2) related signaling pathways are of great significance for thermogenesis and the development of brown and beige adipocytes, the exact roles of mTOR in heat production are controversial. The similarities and disparities in terms of thermogenesis might be ascribed to the use of different animal models and experimental systems, distinct features of brown and beige adipocytes, and the complexity of regulatory networks of mTORC1 and mTORC2 in energy metabolism.
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39
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Wang Y, Zhou H, Palyha O, Mu J. Restoration of insulin receptor improves diabetic phenotype in T2DM mice. JCI Insight 2019; 4:124945. [PMID: 31391336 DOI: 10.1172/jci.insight.124945] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 06/27/2019] [Indexed: 12/14/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM), also known as adult-onset diabetes, is characterized by ineffective insulin action due to insulin resistance in key metabolic tissues. Insulin receptor (IR) plays an important role in insulin signal transduction, defect of which has been considered the fundamental cause of T2DM. IR content reduction in diabetes is one key contributor to the defective insulin signaling and diabetes progression. Rescuing IR levels by transgenic complementation has not been considered as a treatment option because it is limited by uncontrollable expression level, tissue selectivity, or developmental defects. In the current study, we demonstrated that single-dose adeno-associated virus (AAV) vector delivered expression of human IR (hIR) in the liver of inducible IR-knockout mice and significantly improved the diabetic phenotype caused by IR deletion during adulthood. Such an approach was also applied, for the first time to our knowledge, to treating ob/ob mice, a model of severe T2DM attributed to superfluous calorie intake and insulin resistance. Interestingly, similar treatment with AAV-hIR had no obvious effect in healthy animals, indicative of low hypoglycemic risk as a consequence of potential excessive insulin action. The results described here support restoration of IR expression as a safe and effective T2DM therapeutic with a long-lasting profile.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Blood Glucose/analysis
- Dependovirus/genetics
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/pathology
- Diabetes Mellitus, Type 2/therapy
- Disease Models, Animal
- Genetic Therapy/adverse effects
- Genetic Therapy/methods
- Genetic Vectors/administration & dosage
- Genetic Vectors/adverse effects
- Genetic Vectors/genetics
- Humans
- Hypoglycemia/blood
- Hypoglycemia/diagnosis
- Hypoglycemia/genetics
- Insulin/metabolism
- Male
- Mice
- Mice, Knockout
- Receptor, Insulin/genetics
- Receptor, Insulin/metabolism
- Treatment Outcome
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40
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Chia LY, Evans BA, Mukaida S, Bengtsson T, Hutchinson DS, Sato M. Adrenoceptor regulation of the mechanistic target of rapamycin in muscle and adipose tissue. Br J Pharmacol 2019; 176:2433-2448. [PMID: 30740664 PMCID: PMC6592864 DOI: 10.1111/bph.14616] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/08/2019] [Accepted: 01/21/2019] [Indexed: 12/16/2022] Open
Abstract
A vital role of adrenoceptors in metabolism and energy balance has been well documented in the heart, skeletal muscle, and adipose tissue. It has been only recently demonstrated, however, that activation of the mechanistic target of rapamycin (mTOR) makes a significant contribution to various metabolic and physiological responses to adrenoceptor agonists. mTOR exists as two distinct complexes named mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2) and has been shown to play a critical role in protein synthesis, cell proliferation, hypertrophy, mitochondrial function, and glucose uptake. This review will describe the physiological significance of mTORC1 and 2 as a novel paradigm of adrenoceptor signalling in the heart, skeletal muscle, and adipose tissue. Understanding the detailed signalling cascades of adrenoceptors and how they regulate physiological responses is important for identifying new therapeutic targets and identifying novel therapeutic interventions. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.
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Affiliation(s)
- Ling Yeong Chia
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Bronwyn A. Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Saori Mukaida
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner‐Gren InstituteStockholm UniversityStockholmSweden
| | - Dana S. Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
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41
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Inducible Loss of the Aryl Hydrocarbon Receptor Activates Perigonadal White Fat Respiration and Brown Fat Thermogenesis via Fibroblast Growth Factor 21. Int J Mol Sci 2019; 20:ijms20040950. [PMID: 30813227 PMCID: PMC6412252 DOI: 10.3390/ijms20040950] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 02/06/2023] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor highly expressed in hepatocytes. Researchers have employed global and liver-specific conditional Ahr knockout mouse models to characterize the physiological roles of the AHR; however, the gestational timing of AHR loss in these models can complicate efforts to distinguish the direct and indirect effects of post-gestational AHR deficiency. Utilizing a novel tamoxifen-inducible AHR knockout mouse model, we analyzed the effects of hepatocyte-targeted AHR loss in adult mice. The data demonstrate that AHR deficiency significantly reduces weight gain and adiposity, and increases multilocular lipid droplet formation within perigonadal white adipose tissue (gWAT). Protein and mRNA expression of fibroblast growth factor 21 (FGF21), an important hepatokine that activates thermogenesis in brown adipose tissue (BAT) and gWAT, significantly increases upon AHR loss and correlates with a significant increase of BAT and gWAT respiratory capacity. Confirming the role of FGF21 in mediating these effects, this phenotype is reversed in mice concomitantly lacking AHR and FGF21 expression. Chromatin immunoprecipitation analyses suggest that the AHR may constitutively suppress Fgf21 transcription through binding to a newly identified xenobiotic response element within the Fgf21 promoter. The data demonstrate an important AHR-FGF21 regulatory axis that influences adipose biology and may represent a “druggable” therapeutic target for obesity and its related metabolic disorders.
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Yeh YS, Jheng HF, Iwase M, Kim M, Mohri S, Kwon J, Kawarasaki S, Li Y, Takahashi H, Ara T, Nomura W, Kawada T, Goto T. The Mevalonate Pathway Is Indispensable for Adipocyte Survival. iScience 2018; 9:175-191. [PMID: 30396151 DOI: 10.1016/j.isci.2018.10.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/26/2018] [Accepted: 10/16/2018] [Indexed: 01/20/2023] Open
Abstract
The mevalonate pathway is essential for the synthesis of isoprenoids and cholesterol. Adipose tissue is known as a major site for cholesterol storage; however, the role of the local mevalonate pathway and its synthesized isoprenoids remains unclear. In this study, adipose-specific mevalonate pathway-disrupted (aKO) mice were generated through knockout of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase (HMGCR). aKO mice showed serious lipodystrophy accompanied with glucose and lipid metabolic disorders and hepatomegaly. These metabolic variations in aKO mice were dramatically reversed after fat transplantation. In addition, HMGCR-disrupted adipocytes exhibited loss of lipid accumulation and an increase of cell death, which were ameliorated by the supplementation of mevalonate and geranylgeranyl pyrophosphate but not farnesyl pyrophosphate and squalene. Finally, we found that apoptosis may be involved in adipocyte death induced by HMGCR down-regulation. Our findings indicate that the mevalonate pathway is essential for adipocytes and further suggest that this pathway is an important regulator of adipocyte turnover.
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Affiliation(s)
- Yu-Sheng Yeh
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Huei-Fen Jheng
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Mari Iwase
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Minji Kim
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Shinsuke Mohri
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Jungin Kwon
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Satoko Kawarasaki
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Yongjia Li
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Haruya Takahashi
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Takeshi Ara
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Wataru Nomura
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan; Research Unit for Physiological Chemistry, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan
| | - Teruo Kawada
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan; Research Unit for Physiological Chemistry, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan
| | - Tsuyoshi Goto
- Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan; Research Unit for Physiological Chemistry, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan.
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Heine M, Fischer AW, Schlein C, Jung C, Straub LG, Gottschling K, Mangels N, Yuan Y, Nilsson SK, Liebscher G, Chen O, Schreiber R, Zechner R, Scheja L, Heeren J. Lipolysis Triggers a Systemic Insulin Response Essential for Efficient Energy Replenishment of Activated Brown Adipose Tissue in Mice. Cell Metab 2018; 28:644-655.e4. [PMID: 30033199 DOI: 10.1016/j.cmet.2018.06.020] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 04/24/2018] [Accepted: 06/20/2018] [Indexed: 12/31/2022]
Abstract
The coordination of the organ-specific responses regulating systemic energy distribution to replenish lipid stores in acutely activated brown adipose tissue (BAT) remains elusive. Here, we show that short-term cold exposure or acute β3-adrenergic receptor (β3AR) stimulation results in secretion of the anabolic hormone insulin. This process is diminished in adipocyte-specific Atgl-/- mice, indicating that lipolysis in white adipose tissue (WAT) promotes insulin secretion. Inhibition of pancreatic β cells abolished uptake of lipids delivered by triglyceride-rich lipoproteins into activated BAT. Both increased lipid uptake into BAT and whole-body energy expenditure in response to β3AR stimulation were blunted in mice treated with the insulin receptor antagonist S961 or lacking the insulin receptor in brown adipocytes. In conclusion, we introduce the concept that acute cold and β3AR stimulation trigger a systemic response involving WAT, β cells, and BAT, which is essential for insulin-dependent fuel uptake and adaptive thermogenesis.
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Affiliation(s)
- Markus Heine
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Alexander W Fischer
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Christian Schlein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Caroline Jung
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Leon G Straub
- Institute of Food, Nutrition and Health, ETH-Zürich, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
| | - Kristina Gottschling
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Nils Mangels
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Yucheng Yuan
- Department of Chemistry, Brown University, 324 Brook Street, Providence, RI 02912, USA
| | - Stefan K Nilsson
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Gudrun Liebscher
- Biocenter, Division of Cell Biology, Medical University Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Ou Chen
- Department of Chemistry, Brown University, 324 Brook Street, Providence, RI 02912, USA
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
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Deis JA, Guo H, Wu Y, Liu C, Bernlohr DA, Chen X. Lipocalin 2 regulates retinoic acid-induced activation of beige adipocytes. J Mol Endocrinol 2018; 61:115-126. [PMID: 30307164 PMCID: PMC6445544 DOI: 10.1530/jme-18-0017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lipocalin-2 (LCN2) has been previously characterized as an adipokine regulating thermogenic activation of brown adipose tissue and retinoic acid (RA)-induced thermogenesis in mice. The objective of this study was to explore the role and mechanism for LCN2 in the recruitment and retinoic acid-induced activation of brown-like or ‘beige’ adipocytes. We found LCN2 deficiency reduces key markers of thermogenesis including uncoupling protein-1 (UCP1) and peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) in inguinal white adipose tissue (iWAT) and inguinal adipocytes derived from Lcn2 −/− mice. Lcn2 −/− inguinal adipocytes have attenuated insulin-induced upregulation of thermogenic gene expression and p38 mitogen-activated protein kinase (p38MAPK) signaling pathway activation. This is accompanied by a lower basal and maximal oxidative capacity in Lcn2 −/− inguinal adipocytes, indicating mitochondrial dysfunction. Recombinant Lcn2 was able to restore insulin-induced p38MAPK phosphorylation in both WT and Lcn2 −/− inguinal adipocytes. Rosiglitazone treatment during differentiation of Lcn2 −/− adipocytes is able to recruit beige adipocytes at a normal level, however, further activation of beige adipocytes by insulin and RA is impaired in the absence of LCN2. Further, the synergistic effect of insulin and RA on UCP1 and PGC-1α expression is markedly reduced in Lcn2 −/− inguinal adipocytes. Most intriguingly, LCN2 and the retinoic acid receptor-alpha (RAR-α) are concurrently translocated to the plasma membrane of adipocytes in response to insulin, and this insulin-induced RAR-α translocation is absent in adipocytes deficient in LCN2. Our data suggest a novel LCN2-mediated pathway by which RA and insulin synergistically regulates activation of beige adipocytes via a non-genomic pathway of RA action.
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Affiliation(s)
- Jessica A. Deis
- Department of Food Science and Nutrition, Molecular Biology and Biophysics, University of Minnesota, Twin Cities, Minnesota, USA
| | - Hong Guo
- Department of Food Science and Nutrition, Molecular Biology and Biophysics, University of Minnesota, Twin Cities, Minnesota, USA
| | - Yingjie Wu
- Institute for Genomic Engineered Animal Models of Human Diseases, Dalian Medical University, Dalian, China
| | - Chengyu Liu
- Transgenic Core, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - David A. Bernlohr
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Twin Cities, Minnesota, USA
| | - Xiaoli Chen
- Department of Food Science and Nutrition, Molecular Biology and Biophysics, University of Minnesota, Twin Cities, Minnesota, USA
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45
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LincRNA H19 protects from dietary obesity by constraining expression of monoallelic genes in brown fat. Nat Commun 2018; 9:3622. [PMID: 30190464 PMCID: PMC6127097 DOI: 10.1038/s41467-018-05933-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 07/31/2018] [Indexed: 01/22/2023] Open
Abstract
Increasing brown adipose tissue (BAT) thermogenesis in mice and humans improves metabolic health and understanding BAT function is of interest for novel approaches to counteract obesity. The role of long noncoding RNAs (lncRNAs) in these processes remains elusive. We observed maternally expressed, imprinted lncRNA H19 increased upon cold-activation and decreased in obesity in BAT. Inverse correlations of H19 with BMI were also observed in humans. H19 overexpression promoted, while silencing of H19 impaired adipogenesis, oxidative metabolism and mitochondrial respiration in brown but not white adipocytes. In vivo, H19 overexpression protected against DIO, improved insulin sensitivity and mitochondrial biogenesis, whereas fat H19 loss sensitized towards HFD weight gains. Strikingly, paternally expressed genes (PEG) were largely absent from BAT and we demonstrated that H19 recruits PEG-inactivating H19-MBD1 complexes and acts as BAT-selective PEG gatekeeper. This has implications for our understanding how monoallelic gene expression affects metabolism in rodents and, potentially, humans. Brown adipose tissue (BAT) thermogenesis counteracts obesity and promotes metabolic health. The role of long non-coding RNAs (lncRNAs) in the regulation of this process is not well understood. Here the authors identify a maternally expressed lncRNA, H19, that increases BAT oxidative metabolism and energy expenditure.
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Grote CW, Wilson NM, Katz NK, Guilford BL, Ryals JM, Novikova L, Stehno-Bittel L, Wright DE. Deletion of the insulin receptor in sensory neurons increases pancreatic insulin levels. Exp Neurol 2018; 305:97-107. [PMID: 29649429 PMCID: PMC5963702 DOI: 10.1016/j.expneurol.2018.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 11/24/2022]
Abstract
Insulin is known to have neurotrophic properties and loss of insulin support to sensory neurons may contribute to peripheral diabetic neuropathy (PDN). Here, genetically-modified mice were generated in which peripheral sensory neurons lacked the insulin receptor (SNIRKO mice) to determine whether disrupted sensory neuron insulin signaling plays a crucial role in the development of PDN and whether SNIRKO mice develop symptoms of PDN due to reduced insulin neurotrophic support. Our results revealed that SNIRKO mice were euglycemic and never displayed significant changes in a wide range of sensorimotor behaviors, nerve conduction velocity or intraepidermal nerve fiber density. However, SNIRKO mice displayed elevated serum insulin levels, glucose intolerance, and increased insulin content in the islets of Langerhans of the pancreas. These results contribute to the growing idea that sensory innervation of pancreatic islets is key to regulating islet function and that a negative feedback loop of sensory neuron insulin signaling keeps this regulation in balance. Our results suggest that a loss of insulin receptors in sensory neurons does not lead to peripheral nerve dysfunction. The SNIRKO mice will be a powerful tool to investigate sensory neuron insulin signaling and may give a unique insight into the role that sensory neurons play in modifying islet physiology.
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Affiliation(s)
- Caleb W Grote
- Department of Orthopedic Surgery, University of Kansas Medical Center, United States
| | - Natalie M Wilson
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States
| | - Natalie K Katz
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States
| | - Brianne L Guilford
- Department of Applied Health, Southern Illinois University Edwardsville, United States
| | - Janelle M Ryals
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States
| | - Lesya Novikova
- Physical Therapy & Rehabilitation Science, University of Kansas Medical Center, Southern Illinois University Edwardsville, United States
| | - Lisa Stehno-Bittel
- Physical Therapy & Rehabilitation Science, University of Kansas Medical Center, Southern Illinois University Edwardsville, United States
| | - Douglas E Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, United States.
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47
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Page MM, Johnson JD. Mild Suppression of Hyperinsulinemia to Treat Obesity and Insulin Resistance. Trends Endocrinol Metab 2018; 29:389-399. [PMID: 29665988 DOI: 10.1016/j.tem.2018.03.018] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/23/2018] [Accepted: 03/27/2018] [Indexed: 12/14/2022]
Abstract
Insulin plays roles in lipid uptake, lipolysis, and lipogenesis, in addition to controlling blood glucose levels. Excessive circulating insulin is associated with adipose tissue expansion and obesity, yet a causal role for hyperinsulinemia in the development of mammalian obesity has proven controversial, with many researchers suggesting it as a consequence of insulin resistance. Recently, evidence that specifically reducing hyperinsulinemia can prevent and reverse obesity in animal models has been presented. Our experiments, and others in this field, question the current dogma that hyperinsulinemia is a response to obesity and/or insulin resistance. In this review, we discuss preclinical evidence in the context of the broader literature and speculate on the possibility of clinical translation of alternative approaches for treating obesity.
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Affiliation(s)
- Melissa M Page
- Life Sciences Institute Diabetes Research Group and the Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada; Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - James D Johnson
- Life Sciences Institute Diabetes Research Group and the Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada. https://twitter.com/JimJohnsonSci
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48
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Insulin selectively reduces mitochondrial uncoupling in brown adipose tissue in mice. Biochem J 2018; 475:561-569. [PMID: 29170160 DOI: 10.1042/bcj20170736] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/20/2017] [Accepted: 11/22/2017] [Indexed: 12/17/2022]
Abstract
The purpose of the present study was to determine the effects of prolonged hyperinsulinemia on mitochondrial respiration and uncoupling in distinct adipose tissue depots. Sixteen-week-old male mice were injected daily with placebo or insulin to induce an artificial hyperinsulinemia for 28 days. Following the treatment period, mitochondrial respiration and degree of uncoupling were determined in permeabilized perirenal, inguinal, and interscapular adipose tissue. White adipose tissue (WAT) mitochondria (inguinal and perirenal) respire at substantially lower rates compared with brown adipose tissue (BAT). Insulin treatment resulted in a significant reduction in mitochondrial respiration in inguinal WAT (iWAT) and interscapular BAT (iBAT), but not in perirenal WAT (pWAT). Furthermore, these changes were accompanied by an insulin-induced reduction in UCP-1 (uncoupling protein 1) and PGC-1α in iWAT and iBAT only, but not in pWAT or skeletal muscle. Compared with adipose tissue mitochondria in placebo conditions, adipose tissue from hyperinsulinemic mice manifested a site-specific reduction in mitochondrial respiration probably as a result of reduced uncoupling. These results may help explain weight gain so commonly seen with insulin treatment in type 2 diabetes mellitus.
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49
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Li L, Byrd M, Doh K, Dixon PD, Lee H, Tiwari S, Ecelbarger CM. Absence of renal enlargement in fructose-fed proximal-tubule-select insulin receptor (IR), insulin-like-growth factor receptor (IGF1R) double knockout mice. Physiol Rep 2018; 4:4/23/e13052. [PMID: 27923977 PMCID: PMC5357825 DOI: 10.14814/phy2.13052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 10/25/2016] [Accepted: 11/02/2016] [Indexed: 02/02/2023] Open
Abstract
The major site of fructose metabolism in the kidney is the proximal tubule (PT). To test whether insulin and/or IGF1 signaling in the PT is involved in renal structural/functional responses to dietary fructose, we bred mice with dual knockout (KO) of the insulin receptor (IR) and the IGF1 receptor (IGF1R) in PT by Cre-lox recombination, using a γ-glutamyl transferase promoter. KO mice had slightly (~10%) reduced body and kidney weights, as well as, a reduction in mean protein-to-DNA ratio in kidney cortex suggesting smaller cell size. Under control diet, IR and IGF1R protein band densities were 30-50% (P < 0.05) lower than WT, and the relative difference was greater in male animals. Male, but not female KO, also had significantly reduced band densities for Akt (protein kinase B), phosphorylated AktT308 and IRY1162/1163 A high-fructose diet (1-month) led to a significant increase in kidney weight in WT males (12%), but not in KO males or in either genotype of female mice. Kidney enlargement in the WT males was accompanied by a small, insignificant fall in protein-to-DNA ratio, supporting hyperplasia rather than hypertrophy. Fructose feeding of male WT mice led to significantly higher sodium bicarbonate exchanger (NBCe1), sodium hydrogen exchanger (NHE3), sodium phosphate co-transporter (NaPi-2), and transforming growth factor-β (TGF-β) abundances, as compared to male KO, suggesting elevated transport capacity and an early feature of fibrosis may have accompanied the renal enlargement. Overall, IR and/or IGF1R appear to have a role in PT cell size and enlargement in response to high-fructose diet.
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Affiliation(s)
- Lijun Li
- Department of Medicine, Georgetown University, Washington, District of Columbia
| | - Marcus Byrd
- Department of Medicine, Georgetown University, Washington, District of Columbia
| | - Kwame Doh
- Department of Medicine, Georgetown University, Washington, District of Columbia
| | - Patrice D Dixon
- Department of Medicine, Georgetown University, Washington, District of Columbia
| | - Hwal Lee
- Department of Medicine, Georgetown University, Washington, District of Columbia
| | - Swasti Tiwari
- Department of Medicine, Georgetown University, Washington, District of Columbia.,Department of Molecular Medicine & Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
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Abstract
The adult human adipose tissue is predominantly composed of white adipocytes. However, within certain depots, adipose tissue contains thermogenically active brown-like adipocytes, which have been evolutionarily conserved in mammals. This chapter will give a brief overview on the methods used to genetically target and trace both white and brown adipocytes using techniques such as bacterial artificial chromosome (BAC) cloning to create transgenic mouse models and the tools with which genetic recombination is mediated in vivo (e.g., Cre-loxP, CreERT, and Tet-On). The chapter furthermore critically discusses the strength and limitation of the various systems used to target mature white and brown adipocytes (ap2-Cre, Adipoq-Cre, and Ucp1-Cre). Based on these systems, it is evident that our knowledge of mature adipocyte categorization into brown, white, brite, or beige adipocytes is strongly influenced by the use of the various genetic mouse models described in this chapter. Our evaluation of different studies using the aforementioned systems focuses on key genes, which have been reported to maintain adipocyte's function (insulin receptor, Raptor, or Atgl).
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Affiliation(s)
- Christian Wolfrum
- Institute of Food, Nutrition, and Health, ETH Zurich, Zürich, Switzerland
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