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Zhang Y, Luo M, Jia Y, Gao T, Deng L, Gong T, Zhang Z, Cao X, Fu Y. Adipocyte-targeted delivery of rosiglitazone with localized photothermal therapy for the treatment of diet-induced obesity in mice. Acta Biomater 2024; 181:317-332. [PMID: 38643815 DOI: 10.1016/j.actbio.2024.04.029] [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: 02/20/2024] [Revised: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 04/23/2024]
Abstract
Obesity represents a growing public health concern and is closely associated with metabolic complications such as diabetes and fatty liver disease. Anti-obesity medications currently available have limited efficacy in weight loss and are often accompanied by adverse effects. This study proposes a localized photothermal therapy (PTT) combined with adipocyte-targeted delivery of rosiglitazone (RSG) to address obesity. Specifically, cationic albumin nanoparticles (cNPs) were synthesized to deliver RSG precisely to white adipocytes, stimulating the browning process. An IR780-loaded thermosensitive hydrogel was injected and allowed to gel in situ to afford a subcutaneous reservoir that enables localized PTT and controlled release of RSG cNPs. Notably, cNPs significantly enhanced the internalization efficiency in adipocytes in vitro and prolonged the therapeutic retention in the adipose tissue in vivo. Co-administration of RSG cNPs and PTT substantially reduced fat content, induced browning in white adipose tissue in diet-induced obese mice, and mitigated complications such as insulin resistance, fatty liver, and hyperlipidemia. The increased expression of uncoupling protein 1 contributes to enhancing energy expenditure and facilitating adipose metabolism, thereby effectively combating obesity. This therapeutic approach integrates localized PTT with adipocyte-targeted delivery to combat the global obesity epidemic thus offering a promising solution with reduced systemic toxicity and enhanced efficacy. STATEMENT OF SIGNIFICANCE: Cationic albumin nanoparticles are capable of efficient internalization in adipocytes, which may enhance drug targeting to adipose tissue. The combination of rosiglitazone-loaded cationic albumin nanoparticles and local hyperthermia effectively reduces lipid accumulation in adipocytes and induces an upregulated expression of uncoupling protein 1. The combination therapy effectively inhibits fat accumulation, induces adipocyte browning, and regulates systemic metabolism in diet-induced obese mice.
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Affiliation(s)
- Yunxiao Zhang
- Key Laboratory of Drug Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Maoqi Luo
- Key Laboratory of Drug Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Yaxin Jia
- Key Laboratory of Drug Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Tingting Gao
- School of Pharmacy, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, and the Grade 3 Pharmaceutical Chemistry Laboratory of State Administrate of Traditional Chinese Medicine, Hefei, 230032, China
| | - Li Deng
- Key Laboratory of Drug Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Tao Gong
- Key Laboratory of Drug Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Zhirong Zhang
- Key Laboratory of Drug Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Xi Cao
- School of Pharmacy, The First Affiliated Hospital of Anhui Medical University, Anhui Medical University, and the Grade 3 Pharmaceutical Chemistry Laboratory of State Administrate of Traditional Chinese Medicine, Hefei, 230032, China.
| | - Yao Fu
- Key Laboratory of Drug Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
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2
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Zhao Z, Liu S, Qian B, Zhou L, Shi J, Liu J, Xu L, Yang Z. CMKLR1 senses chemerin/resolvin E1 to control adipose thermogenesis and modulate metabolic homeostasis. FUNDAMENTAL RESEARCH 2024; 4:575-588. [PMID: 38933207 PMCID: PMC11197767 DOI: 10.1016/j.fmre.2022.06.014] [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: 02/02/2022] [Revised: 06/01/2022] [Accepted: 06/22/2022] [Indexed: 11/18/2022] Open
Abstract
Induction of beige fat for thermogenesis is a potential therapy to improve homeostasis against obesity. β3-adrenoceptor (β3-AR), a type of G protein-coupled receptor (GPCR), is believed to mediate the thermogenesis of brown fat in mice. However, β3-AR has low expression in human adipose tissue, precluding its activation as a standalone clinical modality. This study aimed at identifying a potential GPCR target to induce beige fat. We found that chemerin chemokine-like receptor 1 (CMKLR1), one of the novel GPCRs, mediated the development of beige fat via its two ligands, chemerin and resolvin E1 (RvE1). The RvE1 levels were decreased in the obese mice, and RvE1 treatment led to a substantial improvement in obese features and augmented beige fat markers. Inversely, despite sharing the same receptor as RvE1, the chemerin levels were increased in obesogenic conditions, and chemerin treatment led to an augmented obese phenotype and a decline of beige fat markers. Moreover, RvE1 and chemerin induced or restrained the development of beige fat, respectively, via the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway. We further showed that RvE1 and chemerin regulated mTORC1 signaling differentially by forming hydrogen bonds with different binding sites of CMKLR1. In conclusion, our study showed that RvE1 and chemerin affected metabolic homeostasis differentially, suggesting that selectively modulating CMKLR1 may be a potential therapeutic target for restoring metabolic homeostasis.
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Affiliation(s)
- Zewei Zhao
- Department of Biochemistry, Molecular Cancer Research Center, School of Medicine, Sun Yat-sen University; Shenzhen, Guangdong 518107, China
| | - Siqi Liu
- Department of Biochemistry, Molecular Cancer Research Center, School of Medicine, Sun Yat-sen University; Shenzhen, Guangdong 518107, China
| | - Bingxiu Qian
- Department of Biochemistry, Molecular Cancer Research Center, School of Medicine, Sun Yat-sen University; Shenzhen, Guangdong 518107, China
| | - Lin Zhou
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University; Guangzhou, Guangdong 510080, China
| | - Jianglin Shi
- Department of Biochemistry, Molecular Cancer Research Center, School of Medicine, Sun Yat-sen University; Shenzhen, Guangdong 518107, China
| | - Junxi Liu
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University; Guangzhou, Guangdong 510080, China
| | - Lin Xu
- School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
| | - Zhonghan Yang
- Department of Biochemistry, Molecular Cancer Research Center, School of Medicine, Sun Yat-sen University; Shenzhen, Guangdong 518107, China
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3
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Allard C, Miralpeix C, López-Gambero AJ, Cota D. mTORC1 in energy expenditure: consequences for obesity. Nat Rev Endocrinol 2024; 20:239-251. [PMID: 38225400 DOI: 10.1038/s41574-023-00934-0] [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] [Accepted: 11/29/2023] [Indexed: 01/17/2024]
Abstract
In eukaryotic cells, the mammalian target of rapamycin complex 1 (sometimes referred to as the mechanistic target of rapamycin complex 1; mTORC1) orchestrates cellular metabolism in response to environmental energy availability. As a result, at the organismal level, mTORC1 signalling regulates the intake, storage and use of energy by acting as a hub for the actions of nutrients and hormones, such as leptin and insulin, in different cell types. It is therefore unsurprising that deregulated mTORC1 signalling is associated with obesity. Strategies that increase energy expenditure offer therapeutic promise for the treatment of obesity. Here we review current evidence illustrating the critical role of mTORC1 signalling in the regulation of energy expenditure and adaptive thermogenesis through its various effects in neuronal circuits, adipose tissue and skeletal muscle. Understanding how mTORC1 signalling in one organ and cell type affects responses in other organs and cell types could be key to developing better, safer treatments targeting this pathway in obesity.
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Affiliation(s)
- Camille Allard
- University of Bordeaux, INSERM, Neurocentre Magendie, Bordeaux, France
| | | | | | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, Bordeaux, France.
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4
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Zhang X, Ding X, Wang C, Le Q, Wu D, Song A, Huang G, Luo L, Luo Y, Yang X, Goins AE, Desai SP, Qiu C, Silva FD, Feldman LE, Zhou J, Spafford MF, Boyd NH, Prossnitz ER, Yang XO, Wang QA, Liu M. Depletion of JunB increases adipocyte thermogenic capacity and ameliorates diet-induced insulin resistance. Nat Metab 2024; 6:78-93. [PMID: 38191667 PMCID: PMC10954369 DOI: 10.1038/s42255-023-00945-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 11/10/2023] [Indexed: 01/10/2024]
Abstract
The coexistence of brown adipocytes with low and high thermogenic activity is a fundamental feature of brown adipose tissue heterogeneity and plasticity. However, the mechanisms that govern thermogenic adipocyte heterogeneity and its significance in obesity and metabolic disease remain poorly understood. Here we show that in male mice, a population of transcription factor jun-B (JunB)-enriched (JunB+) adipocytes within the brown adipose tissue exhibits lower thermogenic capacity compared to high-thermogenic adipocytes. The JunB+ adipocyte population expands in obesity. Depletion of JunB in adipocytes increases the fraction of adipocytes exhibiting high thermogenic capacity, leading to enhanced basal and cold-induced energy expenditure and protection against diet-induced obesity and insulin resistance. Mechanistically, JunB antagonizes the stimulatory effects of PPARγ coactivator-1α on high-thermogenic adipocyte formation by directly binding to the promoter of oestrogen-related receptor alpha, a PPARγ coactivator-1α downstream effector. Taken together, our study uncovers that JunB shapes thermogenic adipocyte heterogeneity, serving a critical role in maintaining systemic metabolic health.
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Affiliation(s)
- Xing Zhang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Xiaofeng Ding
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Chunqing Wang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Que Le
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Dandan Wu
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Anying Song
- Department of Molecular & Cellular Endocrinology, City of Hope Comprehensive Cancer Center, Duarte, CA, USA
| | - Guixiang Huang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, People's Republic of China
| | - Liping Luo
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Yan Luo
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Xin Yang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Aleyah E Goins
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Sharina P Desai
- Autophagy Inflammation and Metabolism Center for Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Chengrui Qiu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Floyd D Silva
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Lily Elizabeth Feldman
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Jianlin Zhou
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, People's Republic of China
| | - Michael F Spafford
- Department of Surgery, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Nathan H Boyd
- Department of Surgery, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Eric R Prossnitz
- Autophagy Inflammation and Metabolism Center for Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- UNM Comprehensive Cancer Center (UNMCCC), University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Xuexian O Yang
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Autophagy Inflammation and Metabolism Center for Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Qiong A Wang
- Department of Molecular & Cellular Endocrinology, City of Hope Comprehensive Cancer Center, Duarte, CA, USA
| | - Meilian Liu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
- Autophagy Inflammation and Metabolism Center for Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
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Ruocco C, Malavazos AE, Ragni M, Carruba MO, Valerio A, Iacobellis G, Nisoli E. Amino acids contribute to adaptive thermogenesis. New insights into the mechanisms of action of recent drugs for metabolic disorders are emerging. Pharmacol Res 2023; 195:106892. [PMID: 37619907 DOI: 10.1016/j.phrs.2023.106892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/28/2023] [Accepted: 08/17/2023] [Indexed: 08/26/2023]
Abstract
Adaptive thermogenesis is the heat production by muscle contractions (shivering thermogenesis) or brown adipose tissue (BAT) and beige fat (non-shivering thermogenesis) in response to external stimuli, including cold exposure. BAT and beige fat communicate with peripheral organs and the brain through a variegate secretory and absorption processes - controlling adipokines, microRNAs, extracellular vesicles, and metabolites - and have received much attention as potential therapeutic targets for managing obesity-related disorders. The sympathetic nervous system and norepinephrine-releasing adipose tissue macrophages (ATM) activate uncoupling protein 1 (UCP1), expressed explicitly in brown and beige adipocytes, dissolving the electrochemical gradient and uncoupling tricarboxylic acid cycle and the electron transport chain from ATP production. Mounting evidence has attracted attention to the multiple effects of dietary and endogenously synthesised amino acids in BAT thermogenesis and metabolic phenotype in animals and humans. However, the mechanisms implicated in these processes have yet to be conclusively characterized. In the present review article, we aim to define the principal investigation areas in this context, including intestinal microbiota constitution, adipose autophagy modulation, and secretome and metabolic fluxes control, which lead to increased brown/beige thermogenesis. Finally, also based on our recent epicardial adipose tissue results, we summarise the evidence supporting the notion that the new dual and triple agonists of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCG) receptor - with never before seen weight loss and insulin-sensitizing efficacy - promote thermogenic-like amino acid profiles in BAT with robust heat production and likely trigger sympathetic activation and adaptive thermogenesis by controlling amino acid metabolism and ATM expansion in BAT and beige fat.
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Affiliation(s)
- Chiara Ruocco
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy
| | - Alexis Elias Malavazos
- Endocrinology Unit, Clinical Nutrition and Cardiovascular Prevention Service, IRCCS Policlinico San Donato, Piazza Edmondo Malan, 2, San Donato Milanese, 20097 Milan, Italy; Department of Biomedical, Surgical and Dental Sciences, University of Milan, via della Commenda, 10, 20122 Milan, Italy
| | - Maurizio Ragni
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy
| | - Michele O Carruba
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy
| | - Alessandra Valerio
- Department of Molecular and Translational Medicine, University of Brescia, viale Europa, 11, 25123 Brescia, Italy
| | - Gianluca Iacobellis
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami, 1400 NW 12th Ave, Miami, FL, USA
| | - Enzo Nisoli
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy.
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Miller RA, Li X, Garcia G. Aging Rate Indicators: Speedometers for Aging Research in Mice. AGING BIOLOGY 2023; 1:10.59368/agingbio.20230003. [PMID: 37694163 PMCID: PMC10486275 DOI: 10.59368/agingbio.20230003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
A "biomarker of aging" is conceptualized as an index of how far an individual has moved along the path from youth to old age. In contrast, an aging rate indicator (ARI) represents a measure of speed, rather than distance, that is, a measure of how rapidly the individual is moving toward the phenotypic changes typical of old age. This essay presents and reviews recent data suggesting common characteristics of slow-aging mice, whether the slowed aging is caused by a mutant allele, the calorie restriction diet, or drugs that slow aging and extend mean and maximal lifespan. Some of the candidate ARIs, shared by nine varieties of slow-aging mice, are physiological changes seen in fat, fat-associated macrophages, muscle, liver, brain, and plasma. Others are molecular measurements, reflecting activity of mTORC1, selective mRNA translation, or each of six MAP kinases in two distinct MAPK cascades in liver, muscle, or kidney. Changes in ARIs are notable in young adult mice after 8 months of drug or diet exposure, are detectable in mutant mice at least as early as 4-6 months of age, and persist until at least 18-22 months. Many of the candidate ARIs are thought to play an influential role in cognition, inflammation, exercise responses, and control of metabolic rate, and are thus plausible as modulators of age-related physiological and neurological illnesses. In principle, screening for drugs that induce alterations in ARIs in normal young adult mice might facilitate the search for preventive medicines that can retard aging and late-life illnesses in mice or in human populations.
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Affiliation(s)
- Richard A. Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI, USA
| | - Xinna Li
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI, USA
| | - Gonzalo Garcia
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI, USA
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Tao R, Stöhr O, Wang C, Qiu W, Copps KD, White MF. Hepatic follistatin increases basal metabolic rate and attenuates diet-induced obesity during hepatic insulin resistance. Mol Metab 2023; 71:101703. [PMID: 36906067 PMCID: PMC10033741 DOI: 10.1016/j.molmet.2023.101703] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/03/2023] [Accepted: 03/05/2023] [Indexed: 03/11/2023] Open
Abstract
OBJECTIVE Body weight change and obesity follow the variance of excess energy input balanced against tightly controlled EE (energy expenditure). Since insulin resistance can reduce energy storage, we investigated whether genetic disruption of hepatic insulin signaling reduced adipose mass with increased EE. METHODS Insulin signaling was disrupted by genetic inactivation of Irs1 (Insulin receptor substrate 1) and Irs2 in hepatocytes of LDKO mice (Irs1L/L·Irs2L/L·CreAlb), creating a state of complete hepatic insulin resistance. We inactivated FoxO1 or the FoxO1-regulated hepatokine Fst (Follistatin) in the liver of LDKO mice by intercrossing LDKO mice with FoxO1L/L or FstL/L mice. We used DEXA (dual-energy X-ray absorptiometry) to assess total lean mass, fat mass and fat percentage, and metabolic cages to measure EE (energy expenditure) and estimate basal metabolic rate (BMR). High-fat diet was used to induce obesity. RESULTS Hepatic disruption of Irs1 and Irs2 (LDKO mice) attenuated HFD (high-fat diet)-induced obesity and increased whole-body EE in a FoxO1-dependent manner. Hepatic disruption of the FoxO1-regulated hepatokine Fst normalized EE in LDKO mice and restored adipose mass during HFD consumption; moreover, hepatic Fst disruption alone increased fat mass accumulation, whereas hepatic overexpression of Fst reduced HFD-induced obesity. Excess circulating Fst in overexpressing mice neutralized Mstn (Myostatin), activating mTORC1-promoted pathways of nutrient uptake and EE in skeletal muscle. Similar to Fst overexpression, direct activation of muscle mTORC1 also reduced adipose mass. CONCLUSIONS Thus, complete hepatic insulin resistance in LDKO mice fed a HFD revealed Fst-mediated communication between the liver and muscle, which might go unnoticed during ordinary hepatic insulin resistance as a mechanism to increase muscle EE and constrain obesity.
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Affiliation(s)
- Rongya Tao
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02215, USA
| | - Oliver Stöhr
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02215, USA
| | - Caixia Wang
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02215, USA
| | - Wei Qiu
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02215, USA
| | - Kyle D Copps
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02215, USA
| | - Morris F White
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02215, USA.
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8
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Song Q, Chen Y, Ding Q, Griffiths A, Liu L, Park J, Liew CW, Nieto N, Li S, Dou X, Jiang Y, Song Z. mTORC1 inhibition uncouples lipolysis and thermogenesis in white adipose tissue to contribute to alcoholic liver disease. Hepatol Commun 2023; 7:e0059. [PMID: 36757400 PMCID: PMC9915967 DOI: 10.1097/hc9.0000000000000059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 12/21/2022] [Indexed: 02/10/2023] Open
Abstract
BACKGROUND Adipose tissue thermogenic activities use fatty acids from lipolysis for heat generation. Therefore, a tight coupling between lipolysis and thermogenesis is physiologically imperative in maintaining not only body temperature but also lipids homeostasis. Adipose tissue dysfunction contributes to alcoholic liver disease (ALD). Here, studies were conducted to examine how alcohol intake affects adipose tissue thermogenic activities and whether altered adipose tissue thermogenesis contributes to ALD. METHODS Both the Lieber-DeCarli and the NIAAA mouse models of ALD were used. Denervation surgery in epididymal fat pads was performed. CL316,243, a selective β3-adrenoceptor agonist, SR59230A, a selective β3 adrenoceptor (ADRB3) antagonist, and rapamycin, a selective mechanistic target of rapamycin complex 1 (mTORC1) inhibitor, were administrated through i.p. injection. Adipocyte-specific Prdm16 knockout mice were subjected to alcohol-containing diet chronically. RESULTS Chronic alcohol consumption, which enhances adipose tissue lipolysis, inhibits thermogenic activities of beige adipocytes in inguinal white adipose tissue (WAT), leading to an uncoupling status between lipolysis and thermogenesis in WAT at both basal and ADRB3 stimulation states. CL316,243 administration exacerbates liver pathologies of ALD. Alcohol intake inhibits mTORC1 activities in WAT. In mice, mTORC1 inhibition by rapamycin inhibits the thermogenesis of iWAT, whereas enhancing WAT lipolysis. Further investigations using adipocyte-specific Prdm16 knockout mice revealed that functional deficiency of beige adipocytes aggravates liver pathologies of ALD, suggesting that the inhibitory effect of alcohol on WAT browning/thermogenesis contributes to ALD pathogenesis. CONCLUSION Chronic alcohol consumption induces an "uncoupling status" between lipolysis and browning/thermogenesis in WAT by inhibiting mTORC1 activation. Diminished WAT browning/thermogenesis, concomitant with enhanced lipolysis, contributes to ALD pathogenesis.
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Affiliation(s)
- Qing Song
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Yingli Chen
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Qinchao Ding
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Alexandra Griffiths
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Lifeng Liu
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Jooman Park
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Chong Wee Liew
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Natalia Nieto
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Songtao Li
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Xiaobing Dou
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Yuwei Jiang
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Zhenyuan Song
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
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9
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Therapeutic Effect of Rapamycin on TDP-43-Related Pathogenesis in Ischemic Stroke. Int J Mol Sci 2022; 24:ijms24010676. [PMID: 36614118 PMCID: PMC9820757 DOI: 10.3390/ijms24010676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/23/2022] [Accepted: 12/23/2022] [Indexed: 01/03/2023] Open
Abstract
Stroke is a major cause of death and disability across the world, and its detrimental impact should not be underestimated. Therapies are available and effective for ischemic stroke (e.g., thrombolytic recanalization and mechanical thrombectomy); however, there are limitations to therapeutic interventions. Recanalization therapy has developed dramatically, while the use of adjunct neuroprotective agents as complementary therapies remains deficient. Pathological TAR DNA-binding protein (TDP-43) has been identified as a major component of insoluble aggregates in numerous neurodegenerative pathologies, including ALS, FTLD and Alzheimer's disease. Here, we show that increased pathological TDP-43 fractions accompanied by impaired mitochondrial function and increased gliosis were observed in an ischemic stroke rat model, suggesting a pathological role of TDP-43 in ischemic stroke. In ischemic rats administered rapamycin, the insoluble TDP-43 fraction was significantly decreased in the ischemic cortex region, accompanied by a recovery of mitochondrial function, the attenuation of cellular apoptosis, a reduction in infarct areas and improvements in motor defects. Accordingly, our results suggest that rapamycin provides neuroprotective benefits not only by ameliorating pathological TDP-43 levels, but also by reversing mitochondrial function and attenuating cell apoptosis in ischemic stroke.
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Deis J, Lin TY, Bushman T, Chen X. Lipocalin 2 Deficiency Alters Prostaglandin Biosynthesis and mTOR Signaling Regulation of Thermogenesis and Lipid Metabolism in Adipocytes. Cells 2022; 11:cells11091535. [PMID: 35563840 PMCID: PMC9105538 DOI: 10.3390/cells11091535] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 02/04/2023] Open
Abstract
Apart from a well-known role in the innate immune system, lipocalin 2 (Lcn2) has been recently characterized as a critical regulator of thermogenesis and lipid metabolism. However, the physiological mechanism through which Lcn2 regulates cellular metabolism and thermogenesis in adipocytes remains unknown. We found that Lcn2 expression and secretion are significantly upregulated by arachidonic acid (AA) and mTORC1 inhibition in differentiated inguinal adipocytes. AA-induced Lcn2 expression and secretion correlate with the inflammatory NFkB activation. Lcn2 deficiency leads to the upregulation of cyclooxygenase-2 (COX2) expression, as well as increased biosynthesis and secretion of prostaglandins (PGs), particularly PGE2 and PGD2, induced by AA in adipocytes. Furthermore, Lcn2 deficiency affects the mTOR signaling regulation of thermogenic gene expression, lipogenesis, and lipolysis. The loss of Lcn2 dismisses the effect of mTORC1 inhibition by rapamycin on COX2, thermogenesis genes, lipogenesis, and lipolysis, but has no impact on p70 S6Kinase-ULK1 activation in Lcn2-deficient adipocytes. We conclude that Lcn2 converges the COX2-PGE2 and mTOR signaling pathways in the regulation of thermogenesis and lipid metabolism in adipocytes.
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Affiliation(s)
- Jessica Deis
- Department of Food Science and Nutrition, University of Minnesota, Twin Cities, MN 55455, USA
| | - Te-Yueh Lin
- Department of Food Science and Nutrition, University of Minnesota, Twin Cities, MN 55455, USA
| | - Theresa Bushman
- Department of Food Science and Nutrition, University of Minnesota, Twin Cities, MN 55455, USA
| | - Xiaoli Chen
- Department of Food Science and Nutrition, University of Minnesota, Twin Cities, MN 55455, USA
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11
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Simcox J, Lamming DW. The central moTOR of metabolism. Dev Cell 2022; 57:691-706. [PMID: 35316619 PMCID: PMC9004513 DOI: 10.1016/j.devcel.2022.02.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/20/2022] [Accepted: 02/24/2022] [Indexed: 12/21/2022]
Abstract
The protein kinase mechanistic target of rapamycin (mTOR) functions as a central regulator of metabolism, integrating diverse nutritional and hormonal cues to control anabolic processes, organismal physiology, and even aging. This review discusses the current state of knowledge regarding the regulation of mTOR signaling and the metabolic regulation of the four macromolecular building blocks of the cell: carbohydrate, nucleic acid, lipid, and protein by mTOR. We review the role of mTOR in the control of organismal physiology and aging through its action in key tissues and discuss the potential for clinical translation of mTOR inhibition for the treatment and prevention of diseases of aging.
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Affiliation(s)
- Judith Simcox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Dudley W Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
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12
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Browning Epicardial Adipose Tissue: Friend or Foe? Cells 2022; 11:cells11060991. [PMID: 35326442 PMCID: PMC8947372 DOI: 10.3390/cells11060991] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 02/08/2023] Open
Abstract
The epicardial adipose tissue (EAT) is the visceral fat depot of the heart which is highly plastic and in direct contact with myocardium and coronary arteries. Because of its singular proximity with the myocardium, the adipokines and pro-inflammatory molecules secreted by this tissue may directly affect the metabolism of the heart and coronary arteries. Its accumulation, measured by recent new non-invasive imaging modalities, has been prospectively associated with the onset and progression of coronary artery disease (CAD) and atrial fibrillation in humans. Recent studies have shown that EAT exhibits beige fat-like features, and express uncoupling protein 1 (UCP-1) at both mRNA and protein levels. However, this thermogenic potential could be lost with age, obesity and CAD. Here we provide an overview of the physiological and pathophysiological relevance of EAT and further discuss whether its thermogenic properties may serve as a target for obesity therapeutic management with a specific focus on the role of immune cells in this beiging phenomenon.
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13
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Sakers A, De Siqueira MK, Seale P, Villanueva CJ. Adipose-tissue plasticity in health and disease. Cell 2022; 185:419-446. [PMID: 35120662 PMCID: PMC11152570 DOI: 10.1016/j.cell.2021.12.016] [Citation(s) in RCA: 254] [Impact Index Per Article: 127.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/08/2021] [Accepted: 12/13/2021] [Indexed: 12/11/2022]
Abstract
Adipose tissue, colloquially known as "fat," is an extraordinarily flexible and heterogeneous organ. While historically viewed as a passive site for energy storage, we now appreciate that adipose tissue regulates many aspects of whole-body physiology, including food intake, maintenance of energy levels, insulin sensitivity, body temperature, and immune responses. A crucial property of adipose tissue is its high degree of plasticity. Physiologic stimuli induce dramatic alterations in adipose-tissue metabolism, structure, and phenotype to meet the needs of the organism. Limitations to this plasticity cause diminished or aberrant responses to physiologic cues and drive the progression of cardiometabolic disease along with other pathological consequences of obesity.
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Affiliation(s)
- Alexander Sakers
- Institute for Diabetes, Obesity & Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Mirian Krystel De Siqueira
- Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, Los Angeles, CA 90095-7070 USA; Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095-7070 USA
| | - Patrick Seale
- Institute for Diabetes, Obesity & Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104 USA.
| | - Claudio J Villanueva
- Molecular, Cellular & Integrative Physiology Program, University of California, Los Angeles, Los Angeles, CA 90095-7070 USA; Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095-7070 USA.
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14
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Castro É, Vieira TS, Oliveira TE, Ortiz-Silva M, Andrade ML, Tomazelli CA, Peixoto AS, Sobrinho CR, Moreno MF, Gilio GR, Moreira RJ, Guimarães RC, Perandini LA, Chimin P, Reckziegel P, Moretti EH, Steiner AA, Laplante M, Festuccia WT. Adipocyte-specific mTORC2 deficiency impairs BAT and iWAT thermogenic capacity without affecting glucose uptake and energy expenditure in cold-acclimated mice. Am J Physiol Endocrinol Metab 2021; 321:E592-E605. [PMID: 34541875 DOI: 10.1152/ajpendo.00587.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Deletion of mechanistic target of rapamycin complex 2 (mTORC2) essential component rapamycin insensitive companion of mTOR (Rictor) by a Cre recombinase under control of the broad, nonadipocyte-specific aP2/FABP4 promoter impairs thermoregulation and brown adipose tissue (BAT) glucose uptake on acute cold exposure. We investigated herein whether adipocyte-specific mTORC2 deficiency affects BAT and inguinal white adipose tissue (iWAT) signaling, metabolism, and thermogenesis in cold-acclimated mice. For this, 8-wk-old male mice bearing Rictor deletion and therefore mTORC2 deficiency in adipocytes (adiponectin-Cre) and littermates controls were either kept at thermoneutrality (30 ± 1°C) or cold-acclimated (10 ± 1°C) for 14 days and evaluated for BAT and iWAT signaling, metabolism, and thermogenesis. Cold acclimation inhibited mTORC2 in BAT and iWAT, but its residual activity is still required for the cold-induced increases in BAT adipocyte number, total UCP-1 content and mRNA levels of proliferation markers Ki67 and cyclin 1 D, and de novo lipogenesis enzymes ATP-citrate lyase and acetyl-CoA carboxylase. In iWAT, mTORC2 residual activity is partially required for the cold-induced increases in multilocular adipocytes, mitochondrial mass, and uncoupling protein 1 (UCP-1) content. Conversely, BAT mTORC1 activity and BAT and iWAT glucose uptake were upregulated by cold independently of mTORC2. Noteworthy, the impairment in BAT and iWAT total UCP-1 content and thermogenic capacity induced by adipocyte mTORC2 deficiency had no major impact on whole body energy expenditure in cold-acclimated mice due to a compensatory activation of muscle shivering. In conclusion, adipocyte mTORC2 deficiency impairs, through different mechanisms, BAT and iWAT total UCP-1 content and thermogenic capacity in cold-acclimated mice, without affecting glucose uptake and whole body energy expenditure.NEW & NOTEWORTHY BAT and iWAT mTORC2 is inhibited by cold acclimation, but its residual activity is required for cold-induced increases in total UCP-1 content and thermogenic capacity, but not glucose uptake and mTORC1 activity. The impaired BAT and iWAT total UCP-1 content and thermogenic capacity induced by adipocyte mTORC2 deficiency are compensated by activation of muscle shivering in cold-acclimated mice.
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Affiliation(s)
- Érique Castro
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Thayna S Vieira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Tiago E Oliveira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Milene Ortiz-Silva
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Maynara L Andrade
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Caroline A Tomazelli
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Albert S Peixoto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Cleyton R Sobrinho
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Mayara F Moreno
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Gustavo R Gilio
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Rafael J Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Raphael C Guimarães
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Luiz A Perandini
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Patricia Chimin
- Department of Physical Education, Physical Education and Sports Center, Londrina State University, Parana, Brazil
| | - Patricia Reckziegel
- Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Sao Paulo, Brazil
| | - Eduardo H Moretti
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil
| | - Alexandre A Steiner
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil
| | - Mathieu Laplante
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, Quebec, Quebec, Canada
- Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Quebec, Canada
| | - William T Festuccia
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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15
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Hoffman JM, Valencak TG. Sex differences and aging: Is there a role of brown adipose tissue? Mol Cell Endocrinol 2021; 531:111310. [PMID: 33989715 PMCID: PMC8195864 DOI: 10.1016/j.mce.2021.111310] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/31/2021] [Accepted: 04/28/2021] [Indexed: 12/12/2022]
Abstract
In every population across the world, women live significantly longer than men; however, the underlying physiological processes that drive these sex differences in age-specific mortality are largely unknown. Recently, the role of adipose tissue in aging and longevity has been a focus of biomedical research in both humans and rodent models. Specifically, brown adipose tissue, a thermoregulatory tissue originally thought to not exist past infancy in humans, has been shown to potentially play a role in health throughout the lifespan. Females have larger adult brown adipose depots that are not just larger in size but also more efficient in non-shivering thermogenesis. This improved functioning of the brown adipose tissue may potentially lead to improved female health, and we hypothesize that this advantage may be of even bigger significance in the older population. Here, we briefly review what is known about sex differences in aging and how sex differences in brown adipose tissue may be contributing to the female lifespan advantage. These questions have usually been addressed in large experimental studies in rodents as a translational model of human aging. Overall, we propose that a better understanding of the thermogenesis-metabolism nexus is necessary in biomedical research, and sex differences in these factors may contribute to the female longevity bias seen in human populations.
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Affiliation(s)
- Jessica M Hoffman
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., CH464, Birmingham, AL, 35294, USA.
| | - Teresa G Valencak
- College of Animal Sciences, Zhejiang University, Zijingang Campus, 866 Yuhangtang Road, 310058, Hangzhou, PR China.
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16
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Guilherme A, Yenilmez B, Bedard AH, Henriques F, Liu D, Lee A, Goldstein L, Kelly M, Nicoloro SM, Chen M, Weinstein L, Collins S, Czech MP. Control of Adipocyte Thermogenesis and Lipogenesis through β3-Adrenergic and Thyroid Hormone Signal Integration. Cell Rep 2021; 31:107598. [PMID: 32375048 PMCID: PMC7676427 DOI: 10.1016/j.celrep.2020.107598] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/24/2020] [Accepted: 04/10/2020] [Indexed: 12/15/2022] Open
Abstract
Here, we show that β adrenergic signaling coordinately upregulates de novo lipogenesis (DNL) and thermogenesis in subcutaneous white adipose tissue (sWAT), and both effects are blocked in mice lacking the cAMP-generating G protein-coupled receptor Gs (Adipo-GsαKO) in adipocytes. However, UCP1 expression but not DNL activation requires rapamycin-sensitive mTORC1. Furthermore, β3-adrenergic agonist CL316243 readily upregulates thermogenic but not lipogenic genes in cultured adipocytes, indicating that additional regulators must operate on DNL in sWAT in vivo. We identify one such factor as thyroid hormone T3, which is elevated locally by adrenergic signaling. T3 administration to wild-type mice enhances both thermogenesis and DNL in sWAT. Mechanistically, T3 action on UCP1 expression in sWAT depends upon cAMP and is blocked in Adipo-GsαKO mice even as elevated DNL persists. Thus, T3 enhances sWAT thermogenesis by amplifying cAMP signaling, while its control of adipocyte DNL can be mediated independently of both cAMP and rapamycin-sensitive mTORC1.
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Affiliation(s)
- Adilson Guilherme
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Batuhan Yenilmez
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Alexander H Bedard
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Felipe Henriques
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Dianxin Liu
- Departments of Medicine, Cardiovascular Medicine, and Molecular Physiology & Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alexandra Lee
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lauren Goldstein
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Mark Kelly
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sarah M Nicoloro
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Min Chen
- Metabolic Diseases Branch, NIDDK, NIH, Bethesda, MD 20892-1752, USA
| | - Lee Weinstein
- Metabolic Diseases Branch, NIDDK, NIH, Bethesda, MD 20892-1752, USA
| | - Sheila Collins
- Departments of Medicine, Cardiovascular Medicine, and Molecular Physiology & Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael P Czech
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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17
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Wu C, Yu P, Sun R. Adipose tissue and age‑dependent insulin resistance: New insights into WAT browning (Review). Int J Mol Med 2021; 47:71. [PMID: 33693956 PMCID: PMC7952244 DOI: 10.3892/ijmm.2021.4904] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 02/03/2021] [Indexed: 12/19/2022] Open
Abstract
Insulin resistance (IR) is defined as impaired insulin function, reduced glucose uptake and increased glucose production, which can result in type II diabetes, metabolic syndrome and even bone metabolic disorders. A possible reason for the increasing incidence of IR is population aging. Adipose tissue (AT) is an important endocrine organ that serves a crucial role in whole-body energy homeostasis. AT can be divided into white AT (WAT), beige AT and brown AT (BAT). Several mechanisms have been previously associated with age-dependent IR in WAT. However, BAT, a metabolically active tissue, controls the levels of plasma glucose and triglyceride metabolism. Therefore, the present review aimed to summarize the mechanisms of age-dependent IR induced by AT and to determine the role of WAT browning in achieving positive therapeutic outcomes in age-dependent IR.
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Affiliation(s)
- Chuanlong Wu
- Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China
| | - Pei Yu
- Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, P.R. China
| | - Ruixin Sun
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032, P.R. China
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18
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Pham HG, Mukherjee S, Choi MJ, Yun JW. BMP11 regulates thermogenesis in white and brown adipocytes. Cell Biochem Funct 2021; 39:496-510. [PMID: 33527439 DOI: 10.1002/cbf.3615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/11/2020] [Accepted: 10/24/2020] [Indexed: 12/29/2022]
Abstract
Bone morphogenetic protein-11 (BMP11), also known as growth differentiation factor-11 (GDF11), is implicated in skeletal development and joint morphogenesis in mammals. However, its functions in adipogenesis and energy homeostasis are mostly unknown. The present study investigates crucial roles of BMP11 in cultured 3T3-L1 white and HIB1B brown adipocytes, using Bmp11 gene depletion and pharmacological inhibition of BMP11. The silencing of Bmp11 markedly decreases the expression levels of brown-fat signature proteins and beige-specific genes in white adipocytes and significantly down-regulates the expression levels of brown fat-specific genes in brown adipocytes. The deficiency of Bmp11 reduces the expressions of lipolytic protein markers in white and brown adipocytes. Moreover, BMP11 induces browning of 3T3-L1 adipocytes via coordination of multiple signalling pathways, including mTORC1-COX2 and p38MAPK-PGC-1α as non-canonical pathways, as well as Smad1/5/8 as a canonical pathway. We believe this study is the first to provide evidence of the potential roles of BMP11 for improvement of lipid catabolism in both cultured white and brown adipocytes, as well as the effect on browning of white adipocytes. Taken together, these results demonstrate the therapeutic potential for the treatment of obesity.
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Affiliation(s)
- Huong Giang Pham
- Department of Biotechnology, Daegu University, Gyeongsan, South Korea
| | - Sulagna Mukherjee
- Department of Biotechnology, Daegu University, Gyeongsan, South Korea
| | - Min Ji Choi
- Department of Biotechnology, Daegu University, Gyeongsan, South Korea
| | - Jong Won Yun
- Department of Biotechnology, Daegu University, Gyeongsan, South Korea
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19
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Lou P, Bi X, Tian Y, Li G, Kang Q, Lv C, Song Y, Xu J, Sheng X, Yang X, Liu R, Meng Q, Ren F, Plikus MV, Liang B, Zhang B, Guo H, Yu Z. MiR-22 modulates brown adipocyte thermogenesis by synergistically activating the glycolytic and mTORC1 signaling pathways. Am J Cancer Res 2021; 11:3607-3623. [PMID: 33664851 PMCID: PMC7914365 DOI: 10.7150/thno.50900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/08/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Brown adipose tissue (BAT) dissipates chemical energy as heat and has the potential to be a protective strategy to prevent obesity. microRNAs (miRNAs) are emerging as important posttranscriptional factors affecting the thermogenic function of BAT. However, the regulatory mechanism underlying miRNA-mediated energy metabolism in BAT is not fully understood. Here, we explored the roles of miR-22 in BAT thermogenesis and energy metabolism. Methods: Using global and conditional knockout mice as in vivo models and primary brown adipocytes as an in vitro system, we investigated the function of miR-22 in BAT thermogenesis in vivo and in vitro. Results: miR-22 expression was upregulated in BAT in response to cold exposure and during brown preadipocyte differentiation. Both global and conditional knockout mice displayed BAT whitening, impaired cold tolerance, and decreased BAT thermogenesis. Moreover, we found that miR-22 deficiency impaired BAT glycolytic capacity, which is critical for thermogenesis. The mechanistic results revealed that miR-22 activated the mTORC1 signaling pathway by directly suppressing Tsc1 and concomitantly directly suppressing Hif1an, an inhibitor of Hif1α, which promotes glycolysis and maintains thermogenesis. Conclusions: Our findings identify miR-22 as a critical regulator in the control of thermogenesis in BAT and as a potential therapeutic target for human metabolic disorders.
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20
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Takata K, Goto T, Kuroda M, Kimura Y, Harada I, Ueda K, Kawada T, Kioka N. Stiffness of the extracellular matrix regulates differentiation into beige adipocytes. Biochem Biophys Res Commun 2020; 532:205-210. [PMID: 32859378 DOI: 10.1016/j.bbrc.2020.08.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 08/11/2020] [Indexed: 11/15/2022]
Abstract
Beige/brite adipocytes, which express high levels of uncoupling protein 1 (UCP1) to generate heat using stored triglycerides, are induced under specific stimuli such as cold exposure in inguinal white adipose tissue (iWAT). Although extracellular microenvironments such as extracellular matrix (ECM) stiffness are known to regulate cell behaviors, including cell differentiation into adipocytes, the effect on iWAT cells is unknown. In this study, we show that rigid ECM promotes the cell spreading of iWAT-derived preadipocytes. Furthermore, the expression of UCP1 and other thermogenic genes in iWAT cells is promoted when the cells are cultured on rigid ECM. The expression of mTOR, a kinase known to regulate the differentiation to beige adipocytes, is decreased on rigid substrates. These results suggest that ECM stiffness plays an important role in the differentiation to beige adipocytes.
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Affiliation(s)
- Kyoko Takata
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Tsuyoshi Goto
- Division of Food Science and Technology, Graduate School of Agriculture, Kyoto University, Uji, 611-0011, Japan
| | - Mito Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Yasuhisa Kimura
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Ichiro Harada
- Medical Products Technology Development Center, R&D Headquarters, Canon Inc., Ohta-ku, Tokyo, 146-8501, Japan
| | - Kazumitsu Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo, Kyoto, 606-8501, Japan
| | - Teruo Kawada
- Division of Food Science and Technology, Graduate School of Agriculture, Kyoto University, Uji, 611-0011, Japan
| | - Noriyuki Kioka
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo, Kyoto, 606-8501, Japan.
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21
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Zhang X, Wu D, Wang C, Luo Y, Ding X, Yang X, Silva F, Arenas S, Weaver JM, Mandell M, Deretic V, Liu M. Sustained activation of autophagy suppresses adipocyte maturation via a lipolysis-dependent mechanism. Autophagy 2020; 16:1668-1682. [PMID: 31840569 PMCID: PMC8386625 DOI: 10.1080/15548627.2019.1703355] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dysregulation of macroautophagy/autophagy is implicated in obesity and insulin resistance. However, it remains poorly defined how autophagy regulates adipocyte development. Using adipose-specific rptor/raptor knockout (KO), atg7 KO and atg7 rptor double-KO mice, we show that inhibiting MTORC1 by RPTOR deficiency led to autophagic sequestration of lipid droplets, formation of LD-containing lysosomes, and elevation of basal and isoproterenol-induced lipolysis in vivo and in primary adipocytes. Despite normal differentiation at an early phase, progressive degradation and shrinkage of cellular LDs and downregulation of adipogenic markers PPARG and PLIN1 occurred in terminal differentiation of rptor KO adipocytes, which was rescued by inhibiting lipolysis or lysosome. In contrast, inactivating autophagy by depletion of ATG7 protected adipocytes against RPTOR deficiency-induced formation of LD-containing lysosomes, LD degradation, and downregulation of adipogenic markers in vitro. Ultimately, atg7 rptor double-KO mice displayed decreased lipolysis, restored adipose tissue development, and upregulated thermogenic gene expression in brown and inguinal adipose tissue compared to RPTOR-deficient mice in vivo. Collectively, our study demonstrates that autophagy plays an important role in regulating adipocyte maturation via a lipophagy and lipolysis-dependent mechanism. ABBREVIATIONS ATG7: autophagy related 7; BAT: brown adipose tissue; CEBPB/C/EBPβ: CCAAT enhancer binding protein beta; DGAT1: diacylglycerol O-acyltransferase 1; eWAT: epididymal white adipose tissue; iWAT: inguinal white adipose tissue; KO: knockout; LD: lipid droplet; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; PLIN1: perepilin 1; PNPLA2/ATGL: patatin-like phospholipase domain containing 2; PPARG/PPARγ: peroxisome proliferator activated receptor gamma; RPTOR: regulatory associated protein of MTOR complex1; TG: triglyceride; ULK1: unc-51 like kinase 1; UCP1: uncoupling protein 1; WAT: white adipose tissue.
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Affiliation(s)
- Xing Zhang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Dandan Wu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Chunqing Wang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Yan Luo
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Xiaofeng Ding
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Xin Yang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Floyd Silva
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Sara Arenas
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - John Michael Weaver
- Autophagy Inflammation and Metabolism Center for Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Michael Mandell
- Autophagy Inflammation and Metabolism Center for Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA,Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Vojo Deretic
- Autophagy Inflammation and Metabolism Center for Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA,Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Meilian Liu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA,CONTACT Meilian Liu Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, USA
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Pena-Leon V, Perez-Lois R, Seoane LM. mTOR Pathway is Involved in Energy Homeostasis Regulation as a Part of the Gut-Brain Axis. Int J Mol Sci 2020; 21:ijms21165715. [PMID: 32784967 PMCID: PMC7460813 DOI: 10.3390/ijms21165715] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022] Open
Abstract
Mammalian, or mechanic, target of rapamycin (mTOR) signaling is a crucial factor in the regulation of the energy balance that functions as an energy sensor in the body. The present review explores how the mTOR/S6k intracellular pathway is involved in modulating the production of different signals such as ghrelin and nesfatin-1 in the gastrointestinal tract to regulate food intake and body weight. The role of gastric mTOR signaling in different physiological processes was studied in depth through different genetic models that allow the modulation of mTOR signaling in the stomach and specifically in gastric X/A type cells. It has been described that mTOR signaling in X/A-like gastric cells has a relevant role in the regulation of glucose and lipid homeostasis due to its interaction with different organs such as liver and adipose tissue. These findings highlight possible therapeutic strategies, with the gut–brain axis being one of the most promising targets in the treatment of obesity.
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Affiliation(s)
- Veronica Pena-Leon
- Grupo Fisiopatología Endocrina, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Instituto de Investigación Sanitaria, Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain; (V.P.-L.); (R.P.-L.)
- Centro de Investigacion Biomedica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706 Santiago de Compostela, Spain
| | - Raquel Perez-Lois
- Grupo Fisiopatología Endocrina, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Instituto de Investigación Sanitaria, Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain; (V.P.-L.); (R.P.-L.)
- Centro de Investigacion Biomedica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706 Santiago de Compostela, Spain
| | - Luisa Maria Seoane
- Grupo Fisiopatología Endocrina, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Instituto de Investigación Sanitaria, Santiago de Compostela, Travesía da Choupana s/n, 15706 Santiago de Compostela, Spain; (V.P.-L.); (R.P.-L.)
- Centro de Investigacion Biomedica en Red Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706 Santiago de Compostela, Spain
- Correspondence:
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23
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Tyagi A, Kamal MA, Poddar NK. Integrated Pathways of COX-2 and mTOR: Roles in Cell Sensing and Alzheimer's Disease. Front Neurosci 2020; 14:693. [PMID: 32742252 PMCID: PMC7364283 DOI: 10.3389/fnins.2020.00693] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022] Open
Abstract
Cyclooxygenases (COX) are enzymes catalyzing arachidonic acid into prostanoids. COX exists in three isoforms: COX-1, 2, and 3. COX-1 and COX-2 have been widely studied in order to explore and understand their involvement in Alzheimer’s disease (AD), a progressive neuroinflammatory dementia. COX-2 was traditionally viewed to be expressed only under pathological conditions and to have detrimental effects in AD pathophysiology and neurodegeneration. However, an increasing number of reports point to much more complex roles of COX-2 in AD. Mammalian/mechanistic target of rapamycin (mTOR) has been considered as a hub which integrates multiple signaling cascades, some of which are also involved in AD progression. COX-2 and mTOR are both involved in environmental sensing, growth, and metabolic processes of the cell. They are also known to act in cooperation in many different cancers and thus, their role together in normal cellular functions as well as AD has been explored in this review. Some of the therapeutic approaches targeting COX-2 and mTOR in AD and cancer are also discussed.
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Affiliation(s)
- Arti Tyagi
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - Mohammad A Kamal
- King Fahad Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Enzymoics, Hebersham, NSW, Australia
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24
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Rokytová I, Mravec B, Lauková M, Vargovič P. Effect of rapamycin on repeated immobilization stress-induced immune alterations in the rat spleen. J Neuroimmunol 2020; 346:577309. [PMID: 32645638 DOI: 10.1016/j.jneuroim.2020.577309] [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: 02/13/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 12/26/2022]
Abstract
Chronic stress modulates immune system functions via neuroendocrine pathways. Rapamycin inhibits activity of immune cells through the mTOR signaling pathway. We investigated the effect of rapamycin (15 mg/kg, 3-times/week) on neuroimmune-endocrine system in the spleen of rats exposed to 42 cycles of 2-h immobilization. Rapamycin enhanced the activity of hypothalamic-pituitary-adrenocortical axis induced by stress exposure, prevented stress-induced expression of natural killer cell markers while reversed stress-evoked decline of Th2 immune response markers. Overall, our findings suggest that rapamycin may act on immune functions not only directly by inhibiting of mTOR in immune cells but also indirectly via modulation of neuroendocrine system.
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Affiliation(s)
- Ivana Rokytová
- Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
| | - Boris Mravec
- Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia; Institute of Physiology, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Marcela Lauková
- Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia; Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, Valhalla, NY, USA
| | - Peter Vargovič
- Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia.
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25
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Iwata W, Unoki-Kubota H, Kato H, Shimizu A, Matsumoto M, Imasawa T, Igarashi A, Matsumoto K, Noda T, Terauchi Y, Nangaku M, Kasuga M, Kaburagi Y. Podocyte-specific deletion of tubular sclerosis complex 2 promotes focal segmental glomerulosclerosis and progressive renal failure. PLoS One 2020; 15:e0229397. [PMID: 32191726 PMCID: PMC7082048 DOI: 10.1371/journal.pone.0229397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 02/05/2020] [Indexed: 02/06/2023] Open
Abstract
Obesity can initiate and accelerate the progression of kidney diseases. However, it remains unclear how obesity affects renal dysfunction. Here, we show that a newly generated podocyte-specific tubular sclerosis complex 2 (Tsc2) knockout mouse model (Tsc2Δpodocyte) develops proteinuria and dies due to end-stage renal dysfunction by 10 weeks of age. Tsc2Δpodocyte mice exhibit an increased glomerular size and focal segmental glomerulosclerosis, including podocyte foot process effacement, mesangial sclerosis and proteinaceous casts. Podocytes isolated from Tsc2Δpodocyte mice show nuclear factor, erythroid derived 2, like 2-mediated increased oxidative stress response on microarray analysis and their autophagic activity is lowered through the mammalian target of rapamycin (mTOR)-unc-51-like kinase 1 pathway. Rapamycin attenuated podocyte dysfunction and extends survival in Tsc2Δpodocyte mice. Additionally, mTOR complex 1 (mTORC1) activity is increased in podocytes of renal biopsy specimens obtained from obese patients with chronic kidney disease. Our work shows that mTORC1 hyperactivation in podocytes leads to severe renal dysfunction and that inhibition of mTORC1 activity in podocytes could be a key therapeutic target for obesity-related kidney diseases.
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Affiliation(s)
- Wakiko Iwata
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
- Department of Endocrinology and Metabolism, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Hiroyuki Unoki-Kubota
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Hideki Kato
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Akira Shimizu
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Michihiro Matsumoto
- Department of Molecular Metabolic Regulation, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Toshiyuki Imasawa
- Kidney Center, National Hospital Organization Chiba-Higashi National Hospital, Chiba, Japan
| | - Arisa Igarashi
- Department of Allergy and Clinical Immunology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Kenji Matsumoto
- Department of Allergy and Clinical Immunology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Tetsuo Noda
- Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masato Kasuga
- National Center for Global Health and Medicine, Tokyo, Japan
| | - Yasushi Kaburagi
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
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26
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Festuccia WT. Regulation of Adipocyte and Macrophage Functions by mTORC1 and 2 in Metabolic Diseases. Mol Nutr Food Res 2020; 65:e1900768. [DOI: 10.1002/mnfr.201900768] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/06/2020] [Indexed: 12/13/2022]
Affiliation(s)
- William T. Festuccia
- Department of Physiology and Biophysics Institute of Biomedical Sciences University of Sao Paulo Sao Paulo 05508000 Brazil
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Mao X, Huang D, Rao C, Du M, Liang M, Li F, Liu B, Huang K. Enoyl coenzyme A hydratase 1 combats obesity and related metabolic disorders by promoting adipose tissue browning. Am J Physiol Endocrinol Metab 2020; 318:E318-E329. [PMID: 31961704 DOI: 10.1152/ajpendo.00424.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Browning of white adipose tissue (WAT) has been recognized as an important strategy for the treatment of obesity, insulin resistance, and diabetes. Enoyl coenzyme A hydratase 1 (ECH1) is a widely known enzyme involved in lipid metabolism. However, whether and how ECH1 is implicated in browning of WAT remain obscure. Adeno-associated, virus-mediated genetic engineering of ECH1 in adipose tissue was used in investigations in mouse models of obesity induced by a high-fat diet (HFD) or browning induced by cold exposure. Metabolic parameters showed that ECH1 overexpression decreased weight gain and improved insulin sensitivity and lipid profile after 8 wk of an HFD. Further work revealed that these changes were associated with enhanced energy expenditure and increased appearance of brown-like adipocytes in inguinal WAT, as verified by a remarkable increase in uncoupling protein 1 and thermogenic gene expression. In vitro, ECH1 induced brown fat-related gene expression in adipocytes differentiated from primary stromal vascular fractions, whereas knockdown of ECH1 reversed this effect. Mechanistically, ECH1 regulated the thermogenic program by inhibiting mammalian target of rapamycin signaling, which may partially explain the potential mechanism for ECH1 regulating adipose browning. In summary, ECH1 may participate in the pathology of obesity by regulating browning of WAT, which probably provides us with a new therapeutic strategy for combating obesity.
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Affiliation(s)
- Xiaoxiang Mao
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dandan Huang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Caijun Rao
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Meng Du
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minglu Liang
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Li
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Baoqing Liu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kai Huang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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28
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Liu Z, Liao W, Yin X, Zheng X, Li Q, Zhang H, Zheng L, Feng X. Resveratrol-induced brown fat-like phenotype in 3T3-L1 adipocytes partly via mTOR pathway. Food Nutr Res 2020; 64:3656. [PMID: 32047421 PMCID: PMC6983979 DOI: 10.29219/fnr.v64.3656] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 12/22/2022] Open
Abstract
Background Browning of white adipose tissues (WAT) is recognized as a novel way to combat obesity and its related comorbidities. Thus, a lot of dietary agents contributing to browning of WAT have been identified. Objective In this study, we try to explore the mechanism of the browning of WAT induced by resveratrol (Res) in 3T3-L1 adipocytes. Methods The levels of cell viability and lipid accumulation were evaluated under different concentrations of Res. Cell signaling pathway analysis was performed to investigate the possible mechanisms of the WAT browning effect of Res in 3T3-L1 cells. Results We found that Res induced the brown fat-like phenotype by activating protein expressions of brown adipocyte-specific markers, such as peroxisome proliferator-activated receptor gamma (PPAR-γ), peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and uncoupling protein 1 (UCP1). Besides, Res reduced lipid accumulation, as shown by Oil Red O staining. The increased small lipid droplets implied that Res-treated 3T3-L1 adipocytes had some features of brown adipocytes. The brown fat-like phenotype in 3T3-L1 adipocytes induced by Res was possibly mediated by activation of mammalian target of rapamycin (mTOR), as brown adipocyte-specific markers were decreased by rapamycin, an inhibitor of mTOR and the MHY1485 treatment, an activator of mTOR, showed the similar effect of Res on browning markers. Conclusions Res induced brown-like adipocyte phenotype in 3T3-L1 adipocytes partly via mTOR pathway, which provided new insights into the utilization of Res to prevent obesity and related comorbidities.
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Affiliation(s)
- Zihui Liu
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
| | - Weiyao Liao
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
| | - Xiaohan Yin
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
| | - Xinjie Zheng
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
| | - Qingrong Li
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
| | - Hongmin Zhang
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
| | - Lin Zheng
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
| | - Xiang Feng
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Guangzhou, China
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29
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Paolella LM, Mukherjee S, Tran CM, Bellaver B, Hugo M, Luongo TS, Shewale SV, Lu W, Chellappa K, Baur JA. mTORC1 restrains adipocyte lipolysis to prevent systemic hyperlipidemia. Mol Metab 2019; 32:136-147. [PMID: 32029223 PMCID: PMC6961719 DOI: 10.1016/j.molmet.2019.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/20/2019] [Accepted: 12/02/2019] [Indexed: 12/11/2022] Open
Abstract
Objective Pharmacological agents targeting the mTOR complexes are used clinically as immunosuppressants and anticancer agents and can extend the lifespan of model organisms. An undesirable side effect of these drugs is hyperlipidemia. Although multiple roles have been described for mTOR complex 1 (mTORC1) in lipid metabolism, the etiology of hyperlipidemia remains incompletely understood. The objective of this study was to determine the influence of adipocyte mTORC1 signaling in systemic lipid homeostasis in vivo. Methods We characterized systemic lipid metabolism in mice lacking the mTORC1 subunit Raptor (RaptoraKO), the key lipolytic enzyme ATGL (ATGLaKO), or both (ATGL-RaptoraKO) in their adipocytes. Results Mice lacking mTORC1 activity in their adipocytes failed to completely suppress lipolysis in the fed state and displayed prominent hypertriglyceridemia and hypercholesterolemia. Blocking lipolysis in their adipose tissue restored normal levels of triglycerides and cholesterol in the fed state as well as the ability to clear triglycerides in an oral fat tolerance test. Conclusions Unsuppressed adipose lipolysis in the fed state interferes with triglyceride clearance and contributes to hyperlipidemia. Adipose tissue mTORC1 activity is necessary for appropriate suppression of lipolysis and for the maintenance of systemic lipid homeostasis. Inhibition of adipose mTORC1 causes hypertriglyceridemia prior to lipodystrophy. Genetically inhibiting lipolysis reverses the increase in plasma TG. Acute pharmacological inhibition of lipolysis reverses the increase in plasma TG caused by rapamycin treatment. Unrestrained lipolysis impairs LPL activity and decreases TG clearance.
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Affiliation(s)
- Lauren M Paolella
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Diabetes, Obesity, and Metabolism, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sarmistha Mukherjee
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Diabetes, Obesity, and Metabolism, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Cassie M Tran
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Diabetes, Obesity, and Metabolism, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Bruna Bellaver
- Institute for Diabetes, Obesity, and Metabolism, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Programa de Pós-graduação em Ciência Biológicas-Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Mindy Hugo
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Timothy S Luongo
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Diabetes, Obesity, and Metabolism, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Swapnil V Shewale
- Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Wenyun Lu
- Lewis-Sigler Institute for Integrative Genomics, Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Karthikeyani Chellappa
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Diabetes, Obesity, and Metabolism, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Joseph A Baur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Diabetes, Obesity, and Metabolism, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Cairó M, Villarroya J. The role of autophagy in brown and beige adipose tissue plasticity. J Physiol Biochem 2019; 76:213-226. [PMID: 31811543 DOI: 10.1007/s13105-019-00708-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/10/2019] [Indexed: 01/04/2023]
Abstract
Since the rediscovery of active brown and beige adipose tissues in humans a decade ago, great efforts have been made to identify the mechanisms underlying the activation and inactivation of these tissues, with the hope of designing potential strategies to fight against obesity and associated metabolic disorders such as type 2 diabetes. Active brown/beige fat increases the energy expenditure and is associated with reduced hyperglycemia and hyperlipidemia, whereas its atrophy and inactivation have been associated with obesity and aging. Autophagy, which is the process by which intracellular components are degraded within the lysosomes, has recently emerged as an important regulatory mechanism of brown/beige fat plasticity. Studies have shown that autophagy participates in the intracellular remodeling events that occur during brown/beige adipogenesis, thermogenic activation, and inactivation. The autophagic degradation of mitochondria appears to be important for the inactivation of brown fat and the transition from beige-to-white adipose tissue. Moreover, autophagic dysregulation in adipose tissues has been associated with obesity. Thus, understanding the regulatory mechanisms that control autophagy in the physiology and pathophysiology of adipose tissues might suggest novel treatments against obesity and its associated metabolic diseases.
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Affiliation(s)
- Montserrat Cairó
- Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Avda Diagonal 643, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) Fisiopatologia de la Obesidad y Nutrición, 28029, Madrid, Spain
| | - Joan Villarroya
- Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Avda Diagonal 643, 08028, Barcelona, Spain.
- Infectious Diseases Unit, Hospital de la Santa Creu i Sant Pau, 08041, Barcelona, Spain.
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Abstract
Adipose tissues, function as energy metabolism and endocrine organ, are closely associated with metabolic diseases such as obesity, insulin resistance and diabetes. Liver kinase B1 (Lkb1) and mechanistic target of rapamycin (mTOR) play crucial roles in regulating energy metabolism and cell growth in adipose tissue. Our recent study generated an adipocyte-specific Lkb1 and mTOR double knockout (DKO) mouse model and found that DKO of Lkb1 and mTOR caused reduction of brown adipose tissue (BAT) and inguinal white adipose tissue (iWAT) mass but increase of liver mass. Moreover, the DKO mice developed fatty liver and insulin resistance but displayed improved glucose tolerance and were resistant to high-fat diet (HFD) -induced obesity. In this commentary, we compare the similarities and differences of the phenotypes found in the DKO mice and Lkb1 or mTOR or mTOR complex 1 (mTORC1) or mTOR complex 2 (mTORC2) single knockout mice. Furthermore, we discuss the potential regulatory mechanism that results in the overlapping or distinct phenotypes found in these models.
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Affiliation(s)
- Ziye Xu
- Institute of Feed Science, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, Zhejiang, China
- Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wenjing You
- Institute of Feed Science, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, Zhejiang, China
- Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Fengqin Wang
- Institute of Feed Science, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, Zhejiang, China
- Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yizhen Wang
- Institute of Feed Science, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, Zhejiang, China
- Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tizhong Shan
- Institute of Feed Science, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Hangzhou, Zhejiang, China
- Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
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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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Yu D, Tomasiewicz JL, Yang SE, Miller BR, Wakai MH, Sherman DS, Cummings NE, Baar EL, Brinkman JA, Syed FA, Lamming DW. Calorie-Restriction-Induced Insulin Sensitivity Is Mediated by Adipose mTORC2 and Not Required for Lifespan Extension. Cell Rep 2019; 29:236-248.e3. [PMID: 31577953 PMCID: PMC6820997 DOI: 10.1016/j.celrep.2019.08.084] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 07/29/2019] [Accepted: 08/27/2019] [Indexed: 01/26/2023] Open
Abstract
Calorie restriction (CR) extends the healthspan and lifespan of diverse species. In mammals, a broadly conserved metabolic effect of CR is improved insulin sensitivity, which may mediate the beneficial effects of a CR diet. This model has been challenged by the identification of interventions that extend lifespan and healthspan yet promote insulin resistance. These include rapamycin, which extends mouse lifespan yet induces insulin resistance by disrupting mTORC2 (mechanistic target of rapamycin complex 2). Here, we induce insulin resistance by genetically disrupting adipose mTORC2 via tissue-specific deletion of the mTORC2 component Rictor (AQ-RKO). Loss of adipose mTORC2 blunts the metabolic adaptation to CR and prevents whole-body sensitization to insulin. Despite this, AQ-RKO mice subject to CR experience the same increase in fitness and lifespan on a CR diet as wild-type mice. We conclude that the CR-induced improvement in insulin sensitivity is dispensable for the effects of CR on fitness and longevity.
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Affiliation(s)
- Deyang Yu
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA; Molecular and Environmental Toxicology Program, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Shany E Yang
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Blake R Miller
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Matthew H Wakai
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Dawn S Sherman
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Nicole E Cummings
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA; Endocrinology and Reproductive Physiology Graduate Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Emma L Baar
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Jacqueline A Brinkman
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Faizan A Syed
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Dudley W Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA; Molecular and Environmental Toxicology Program, University of Wisconsin-Madison, Madison, WI, USA; Endocrinology and Reproductive Physiology Graduate Training Program, University of Wisconsin-Madison, Madison, WI, USA; University of Wisconsin Carbone Cancer Center, Madison, WI, USA.
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Abstract
Significance: Alterations in adipose tissue function have profound consequences on whole body energy homeostasis because this tissue is central for fat accumulation, energy expenditure, glucose and insulin metabolism, and hormonal regulation. With the obesity reaching epidemic proportions globally, it is important to understand the mechanisms leading to adipose tissue malfunction. Recent Advances: Autophagy has originally been viewed as an adaptive response to cellular stress, but in recent years this process was shown to regulate important cellular processes. In adipose tissue, autophagy is a key regulator of white adipose tissue (WAT) and brown adipose tissue (BAT) adipogenesis, and dysregulated autophagy impairs fat accumulation both in vitro and in vivo. Animal studies have also suggested an important role for autophagy and mitophagy during the transition from beige to white fat. Human studies have provided evidence for altered autophagy in WAT, and these alterations correlated with the degree of insulin resistance. Critical Issues: Despite these important advances in the study of autophagy in adipose tissue, we still do not understand the physiological role of autophagy in mature white and brown adipocytes. Furthermore, several human studies involving autophagy assessment were performed on whole adipose tissue, which complicates the interpretation of the results considering the cellular heterogeneity of this tissue. Future Directions: Future studies will undoubtedly expand our understanding of the role of autophagy in fully differentiated adipocytes, and uncover novel cross-talks between this tissue and other organs in regulating lipid metabolism, redox signaling, energy homeostasis, and insulin sensitivity.
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Affiliation(s)
- Maroua Ferhat
- Program in Molecular Medicine, Department of Nutrition and Integrative Physiology, College of Health, University of Utah, Salt Lake City, Utah
| | - Katsuhiko Funai
- Program in Molecular Medicine, Department of Nutrition and Integrative Physiology, College of Health, University of Utah, Salt Lake City, Utah
| | - Sihem Boudina
- Program in Molecular Medicine, Department of Nutrition and Integrative Physiology, College of Health, University of Utah, Salt Lake City, Utah
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35
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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 DOI: 10.1111/bph.14616] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [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 Sciences, Monash University, Melbourne, Victoria, Australia
| | - Bronwyn A Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia
| | - Saori Mukaida
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Dana S Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia
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36
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Abstract
Obesity is a medical condition that impacts on all levels of society and causes numerous comorbidities, such as diabetes, cardiovascular disease, and cancer. We assessed the suitability of targeting enolase, a glycolysis pathway enzyme with multiple, secondary functions in cells, to treat obesity. Treating adipocytes with ENOblock, a novel modulator of these secondary ‘moonlighting’ functions of enolase, suppressed the adipogenic program and induced mitochondrial uncoupling. Obese animals treated with ENOblock showed a reduction in body weight and increased core body temperature. Metabolic and inflammatory parameters were improved in the liver, adipose tissue and hippocampus. The mechanism of ENOblock was identified as transcriptional repression of master regulators of lipid homeostasis (Srebp-1a and Srebp-1c), gluconeogenesis (Pck-1) and inflammation (Tnf-α and Il-6). ENOblock treatment also reduced body weight gain, lowered cumulative food intake and increased fecal lipid content in mice fed a high fat diet. Our results support the further drug development of ENOblock as a therapeutic for obesity and suggest enolase as a new target for this disorder.
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37
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Green CL, Lamming DW. Regulation of metabolic health by essential dietary amino acids. Mech Ageing Dev 2019; 177:186-200. [PMID: 30044947 PMCID: PMC6333505 DOI: 10.1016/j.mad.2018.07.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/27/2018] [Accepted: 07/16/2018] [Indexed: 12/22/2022]
Abstract
Although the beneficial effects of calorie restriction (CR) on health and aging were first observed a century ago, the specific macronutrients and molecular processes that mediate the effect of CR have been heavily debated. Recently, it has become clear that dietary protein plays a key role in regulating both metabolic health and longevity, and that both the quantity and quality - the specific amino acid composition - of dietary protein mediates metabolic health. Here, we discuss recent findings in model organisms ranging from yeast to mice and humans regarding the influence of dietary protein as well as specific amino acids on metabolic health, and the physiological and molecular mechanisms which may mediate these effects. We then discuss recent findings which suggest that the restriction of specific dietary amino acids may be a potent therapy to treat or prevent metabolic syndrome. Finally, we discuss the potential for dietary restriction of specific amino acids - or pharmaceuticals which harness these same mechanisms - to promote healthy aging.
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Affiliation(s)
- Cara L Green
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Dudley W Lamming
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI, USA.
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38
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Igarashi Y, Nawaz A, Kado T, Bilal M, Kuwano T, Yamamoto S, Sasahara M, Jiuxiang X, Inujima A, Koizumi K, Imura J, Shibahara N, Usui I, Fujisaka S, Tobe K. Partial depletion of CD206-positive M2-like macrophages induces proliferation of beige progenitors and enhances browning after cold stimulation. Sci Rep 2018; 8:14567. [PMID: 30275453 PMCID: PMC6167387 DOI: 10.1038/s41598-018-32803-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/14/2018] [Indexed: 12/30/2022] Open
Abstract
Beige adipocytes are an inducible form of thermogenic adipocytes that become interspersed within white adipose tissue (WAT) depots in response to cold exposure. Previous studies have shown that type 2 cytokines and M2 macrophages induce cold-induced browning in inguinal WAT (ingWAT) by producing catecholamines. Exactly how the conditional and partial depletion of CD206+ M2-like macrophages regulates the cold-induced browning of ingWAT, however, remains unknown. We examined the role of CD206+ M2-like macrophages in the cold-induced browning of WAT using genetically engineered CD206DTR mice, in which CD206+ M2-like macrophages were conditionally depleted. The partial depletion of CD206+ M2-like enhanced UCP1 expression in ingWAT, as shown by immunostaining, and also upregulated the expression of Ucp1 and other browning-related marker genes in ingWAT after cold exposure. A flow cytometry analysis showed that the partial depletion of CD206+ M2-like macrophages caused an increase in the number of beige progenitors in ingWAT in response to cold. Thus, we concluded that CD206+ M2-like macrophages inhibit the proliferation of beige progenitors and that the partial depletion of CD206+ M2-like macrophages releases this inhibition, thereby enhancing browning and insulin sensitivity.
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Affiliation(s)
- Yoshiko Igarashi
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Allah Nawaz
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan.
- Department of Metabolism and Nutrition, University of Toyama, Toyama, 930-0194, Japan.
- JSPS International Research Fellow, Department of Metabolism and Nutrition, University of Toyama, Toyama, 930-0194, Japan.
| | - Tomonobu Kado
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Muhammad Bilal
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Takahide Kuwano
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Seiji Yamamoto
- Department of Pathology, University of Toyama, Toyama, 930-0194, Japan
| | - Masakiyo Sasahara
- Department of Pathology, University of Toyama, Toyama, 930-0194, Japan
| | - Xu Jiuxiang
- Division of Kampo Diagnostics, Institute of Natural Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Akiko Inujima
- Division of Kampo Diagnostics, Institute of Natural Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Keiichi Koizumi
- Division of Kampo Diagnostics, Institute of Natural Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Johji Imura
- Department of Diagnostic Pathology, University of Toyama, Toyama, 930-0194, Japan
| | - Naotoshi Shibahara
- Division of Kampo Diagnostics, Institute of Natural Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Isao Usui
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan
- Department of Endocrinology and Metabolism, Dokkyo Medical University, Tochigi, 321-0293, Japan
| | - Shiho Fujisaka
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Kazuyuki Tobe
- First Department of Internal Medicine, University of Toyama, Toyama, 930-0194, Japan.
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39
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Abstract
PURPOSE OF REVIEW Obesity is a major risk factor for the development of hypertension (HTN), a leading cause of cardiovascular morbidity and mortality. Growing body of research suggests that adipose tissue function is directly associated with the pathogenesis of obesity-related HTN. In this review, we will discuss recent research on the role of adipose tissue in blood pressure (BP) regulation and activation of brown adipose tissue (BAT) as a potentially new therapeutic means for obesity-related HTN. RECENT FINDINGS Adipose tissue provides mechanical protection of the blood vessels and plays a role in regulation of vascular tone. Exercise and fasting activate BAT and induce browning of white adipose tissue (WAT). BAT-secreted FGF21 lowers BP and protects against HTN. Browning of perivascular WAT improves HTN. New insights on WAT browning and BAT activation can open new avenues of potential therapeutic interventions to treat obesity-related HTN.
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Affiliation(s)
- Eashita Das
- Translational Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
- Department of Microbiology, Siliguri College, North Bengal University, Siliguri, West Bengal, 734001, India
| | - Joon Ho Moon
- Translational Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
| | - Ju Hee Lee
- Translational Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Nikita Thakkar
- Translational Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
| | - Zdenka Pausova
- Translational Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
| | - Hoon-Ki Sung
- Translational Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada.
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.
- Banting and Best Diabetes Centre, University of Toronto, Toronto, Canada.
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40
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Zhang X, Luo Y, Wang C, Ding X, Yang X, Wu D, Silva F, Yang Z, Zhou Q, Wang L, Wang X, Zhou J, Boyd N, Spafford M, Burge M, Yang XO, Liu M. Adipose mTORC1 Suppresses Prostaglandin Signaling and Beige Adipogenesis via the CRTC2-COX-2 Pathway. Cell Rep 2018; 24:3180-3193. [PMID: 30232001 PMCID: PMC6287973 DOI: 10.1016/j.celrep.2018.08.055] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 07/30/2018] [Accepted: 08/17/2018] [Indexed: 01/02/2023] Open
Abstract
Beige adipocytes are present in white adipose tissue (WAT) and have thermogenic capacity to orchestrate substantial energy metabolism and counteract obesity. However, adipocyte-derived signals that act on progenitor cells to control beige adipogenesis remain poorly defined. Here, we show that adipose-specific depletion of Raptor, a key component of mTORC1, promoted beige adipogenesis through prostaglandins (PGs) synthesized by cyclooxygenase-2 (COX-2). Moreover, Raptor-deficient mice were resistant to diet-induced obesity and COX-2 downregulation. Mechanistically, mTORC1 suppressed COX-2 by phosphorylation of CREB-regulated transcription coactivator 2 (CRTC2) and subsequent dissociation of CREB to cox-2 promoter in adipocytes. PG treatment stimulated PKA and promoted differentiation of progenitor cells to beige adipocytes in culture. Ultimately, we show that pharmacological inhibition or suppression of COX-2 attenuated mTORC1 inhibition-induced thermogenic gene expression in inguinal WAT in vivo and in vitro. Our study identifies adipocyte-derived PGs as key regulators of white adipocyte browning, which occurs through mTORC1 and CRTC2.
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Affiliation(s)
- Xing Zhang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Key Laboratory of Protein Chemistry and Development Biology of State Education Ministry of China, College of Life Science, Hunan Normal University, Changsha, Hunan, China
| | - Yan Luo
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chunqing Wang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Xiaofeng Ding
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Key Laboratory of Protein Chemistry and Development Biology of State Education Ministry of China, College of Life Science, Hunan Normal University, Changsha, Hunan, China
| | - Xin Yang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Dandan Wu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Floyd Silva
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Zijiang Yang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Qin Zhou
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Lu Wang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Xiaoqing Wang
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Department of Geriatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jianlin Zhou
- Key Laboratory of Protein Chemistry and Development Biology of State Education Ministry of China, College of Life Science, Hunan Normal University, Changsha, Hunan, China
| | - Nathan Boyd
- Department of Surgery, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Michael Spafford
- Department of Surgery, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Mark Burge
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Xuexian O Yang
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Autophagy, Inflammation and Metabolism Center of Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Meilian Liu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA; Autophagy, Inflammation and Metabolism Center of Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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41
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den Hartigh LJ, Goodspeed L, Wang SA, Kenerson HL, Omer M, O'Brien KD, Ladiges W, Yeung R, Subramanian S. Chronic oral rapamycin decreases adiposity, hepatic triglycerides and insulin resistance in male mice fed a diet high in sucrose and saturated fat. Exp Physiol 2018; 103:1469-1480. [PMID: 30117227 DOI: 10.1113/ep087207] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 08/09/2018] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Whether chronic oral rapamycin promotes beneficial effects on glucose/lipid metabolism and energy balance when administered to mice with an obesogenic diet rich in saturated fat and sucrose has not been explored. What is the main finding and its importance? Chronic oral rapamycin reduces body weight and fat gain, improves insulin sensitivity and reduces hepatic steatosis when administered to mice with a high-fat, high-sucrose diet. In addition, we make the new observation that there appear to be tissue-specific effects of rapamycin. Although rapamycin appears to impart its effects mainly on visceral adipose tissue, its effects on insulin sensitivity are mediated by subcutaneous adipose tissue. ABSTRACT Excess adiposity is commonly associated with insulin resistance, which can increase the risk of cardiovascular disease. However, the exact molecular mechanisms by which obesity results in insulin resistance are yet to be understood clearly. The intracellular nutrient-sensing protein, mechanistic target of rapamycin (mTOR), is a crucial signalling component in the development of obesity-associated insulin resistance. Given that increased tissue activation of mTOR complex-1 (mTORC1) occurs in obesity, diabetes and ageing, we hypothesized that pharmacological inhibition of mTORC1 would improve metabolic dysregulation in diet-induced obesity. We administered continuous rapamycin, a specific mTORC1 inhibitor, orally to C57BL/6J mice concurrently with a high-fat, high-sucrose (HFHS) diet for 20 weeks. The control group received placebo microcapsules. Rapamycin-treated mice showed significantly reduced weight gain and adiposity (33.6 ± 4.9 versus 40.4 ± 3.0% body fat, P < 0.001, n = 8 mice per group), despite increased or equivalent food intake compared with the placebo group. The rapamycin-fed mice also demonstrated reduced plasma glucose (252 ± 57 versus 297 ± 67 mg dl-1 , P < 0.001) and improved insulin sensitivity during insulin and glucose tolerance testing. Rapamycin-treated mice also had lower plasma triglycerides (48 ± 13 versus 67 ± 11 mg/dL, P < 0.01) and hepatic triglyceride content (89 ± 15 versus 110 ± 19 mg/g liver, P < 0.05) compared with the placebo group. A moderately low dose of rapamycin decreased adiposity and improved the metabolic profile in a model of diet-induced obesity. These data suggest that low-grade chronic mTORC1 inhibition might be a potential strategy for anti-obesity therapies.
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Affiliation(s)
- Laura J den Hartigh
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Leela Goodspeed
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Shari A Wang
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Heidi L Kenerson
- Department of Surgery, University of Washington, Seattle, WA, 98019, USA
| | - Mohamed Omer
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
| | - Kevin D O'Brien
- Diabetes Institute, University of Washington, Seattle, WA, 98019, USA.,Division of Cardiology, University of Washington, Seattle, WA, 98019, USA
| | - Warren Ladiges
- Department of Comparative Medicine, University of Washington, Seattle, WA, 98019, USA
| | - Raymond Yeung
- Department of Surgery, University of Washington, Seattle, WA, 98019, USA
| | - Savitha Subramanian
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, 98019, USA.,Diabetes Institute, University of Washington, Seattle, WA, 98019, USA
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42
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Knuth CM, Peppler WT, Townsend LK, Miotto PM, Gudiksen A, Wright DC. Prior exercise training improves cold tolerance independent of indices associated with non-shivering thermogenesis. J Physiol 2018; 596:4375-4391. [PMID: 30109697 DOI: 10.1113/jp276228] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/12/2018] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Mammals defend against cold-induced reductions in body temperature through both shivering and non-shivering thermogenesis. The activation of non-shivering thermogenesis is primarily driven by uncoupling protein-1 in brown adipose tissue and to a lesser degree by the browning of white adipose tissue. Endurance exercise has also been shown to increase markers of white adipose tissue browning. This study aimed to determine whether prior exercise training would alter the response to a cold challenge and if this would be associated with differences in indices of non-shivering thermogenesis. It is shown that exercise training protects against cold-induced weight loss by increasing food intake. Exercise-trained mice were better able to maintain their core temperature, independent of differences in markers of non-shivering thermogenesis. ABSTRACT Shivering is one of the first defences against cold, and as skeletal muscle fatigues there is an increased reliance on non-shivering thermogenesis. Brown and beige adipose tissues are the primary thermogenic tissues regulating this process. Exercise has also been shown to increase the thermogenic capacity of subcutaneous white adipose tissue. Whether exercise has an effect on the adaptations to cold stress within adipose tissue and skeletal muscle remains to be shown. Male C57BL/6 mice were either subjected to voluntary wheel running or remained sedentary for 12 days. Exercise led to decreased body weight and increased glucose tolerance. Mice were then divided into groups kept at 25°C room temperature or a cold challenge of 4°C for 48 h. Exercised mice were protected against cold-induced reductions in weight and in parallel with increased food intake. Providing exercised mice with the same amount of food as sedentary mice eliminated the protection against cold-induced weight loss. Cold exposure led to greater reductions in rectal temperature in sedentary compared to exercised mice. This protective effect was not explained by differences in the browning of white adipose tissue or brown adipose tissue mass. Similarly, the ability of the β3 -adrenergic agonist CL 316,243 to increase energy expenditure was attenuated in previously exercised mice, suggesting that the activation of uncoupling protein-1 in brown and/or beige adipocytes is not the source of protective effects. We speculate that the protection against cold-induced reductions in rectal temperature could potentially be linked to exercise-induced alterations in skeletal muscle.
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Affiliation(s)
- Carly M Knuth
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Willem T Peppler
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Logan K Townsend
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Paula M Miotto
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Anders Gudiksen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1
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Fu W, Liu Y, Sun C, Yin H. Transient p53 inhibition sensitizes aged white adipose tissue for beige adipocyte recruitment by blocking mitophagy. FASEB J 2018; 33:844-856. [PMID: 30052487 DOI: 10.1096/fj.201800577r] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Aging of white adipose tissue (WAT) is associated with reduced insulin sensitivity, which contributes to whole-body glucose intolerance. WAT aging in mice impairs cold-induced beige adipocyte recruitment (beiging), which has been attributed to the senescence of adipose progenitor cells. Tumor suppressor p53 has also been implicated in WAT aging. However, whether p53-related cellular aging in mature white adipocytes is causative of age-impaired WAT beiging remains unknown. It is also unclear whether transient p53 inhibition can rescue WAT beiging. Herein, we report that p53 increased in adipose tissues of 28-wk-old (aged) mice with impaired beiging capability. Cold exposure decreased p53 in beiging WAT of young mice but not in aged mice. In aged mice, inducible p53 ablation in differentiated adipocytes restored cold-induced WAT beiging and augmented whole-body energy expenditure and insulin sensitivity. Transient pharmacological inhibition of p53 led to the same beneficial effects. Mechanistically, cold exposure repressed autophagy in beiging WAT of young mice yet increased autophagy in aged WAT. p53-ablation reduced microtubule-associated protein light chain 3-mediated mitochondria clearance (mitophagy) and hence facilitated the increase of mitochondria during beiging. These findings suggest that p53-induced mitophagy in aged white adipocytes impedes WAT beiging and may be therapeutically targeted to improve insulin sensitivity in aged WAT.-Fu, W., Liu, Y., Sun, C., Yin, H. Transient p53 inhibition sensitizes aged white adipose tissue for beige adipocyte recruitment by blocking mitophagy.
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Affiliation(s)
- Wenyan Fu
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.,Center for Molecular Medicine, The University of Georgia, Athens, Georgia, USA; and
| | - Yang Liu
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.,Center for Molecular Medicine, The University of Georgia, Athens, Georgia, USA; and
| | - Christina Sun
- Department of Biological Sciences, Augusta University, Augusta, Georgia, USA
| | - Hang Yin
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.,Center for Molecular Medicine, The University of Georgia, Athens, Georgia, USA; and
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44
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Role of mTOR in Glucose and Lipid Metabolism. Int J Mol Sci 2018; 19:ijms19072043. [PMID: 30011848 PMCID: PMC6073766 DOI: 10.3390/ijms19072043] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 02/06/2023] Open
Abstract
The mammalian target of rapamycin, mTOR is the master regulator of a cell’s growth and metabolic state in response to nutrients, growth factors and many extracellular cues. Its dysregulation leads to a number of metabolic pathological conditions, including obesity and type 2 diabetes. Here, we review recent findings on the role of mTOR in major metabolic organs, such as adipose tissues, liver, muscle, pancreas and brain. And their potentials as the mTOR related pharmacological targets will be also discussed.
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45
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ZHANG J, WU H, MA S, JING F, YU C, GAO L, ZHAO J. Transcription Regulators and Hormones Involved in the Development of Brown Fat and White Fat Browning: Transcriptional and Hormonal Control of Brown/Beige Fat Development. Physiol Res 2018. [DOI: 10.33549/physiolres.933650] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The high prevalence of obesity and related metabolic complications has inspired research on adipose tissues. Three kinds of adipose tissues are identified in mammals: brown adipose tissue (BAT), beige or brite adipose tissue and white adipose tissue (WAT). Beige adipocytes share some characteristics with brown adipocytes such as the expression of UCP1. Beige adipocytes can be activated by environmental stimuli or pharmacological treatment, and this change is accompanied by an increase in energy consumption. This process is called white browning, and it facilitates the maintenance of a lean and healthy phenotype. Thus, promoting beige adipocyte development in WAT shows promise as a new strategy in treating obesity and related metabolic consequences. In this review, we summarized the current understanding of the regulators and hormones that participate in the development of brown fat and white fat browning.
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Affiliation(s)
| | | | | | | | | | | | - J. ZHAO
- Department of Endocrinology, Shandong Provincial Hospital affiliated with Shandong University, Jinan, Shandong, China
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46
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Xiong Y, Xu Z, Wang Y, Kuang S, Shan T. Adipocyte-specific DKO of Lkb1 and mTOR protects mice against HFD-induced obesity, but results in insulin resistance. J Lipid Res 2018; 59:974-981. [PMID: 29636366 DOI: 10.1194/jlr.m081463] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 04/01/2018] [Indexed: 12/14/2022] Open
Abstract
Liver kinase B1 (Lkb1) and mammalian target of rapamycin (mTOR) are key regulators of energy metabolism and cell growth. We have previously reported that adipocyte-specific KO of Lkb1 or mTOR in mice results in distinct developmental and metabolic phenotypes. Here, we aimed to assess how genetic KO of both Lkb1 and mTOR affects adipose tissue development and function in energy homeostasis. We used Adiponectin-Cre to drive adipocyte-specific double KO (DKO) of Lkb1 and mTOR in mice. We performed indirect calorimetry, glucose and insulin tolerance tests, and gene expression assays on the DKO and WT mice. We found that DKO of Lkb1 and mTOR results in reductions of brown adipose tissue and inguinal white adipose tissue mass, but in increases of liver mass. Notably, the DKO mice developed fatty liver and insulin resistance, but displayed improved glucose tolerance after high-fat diet (HFD)-feeding. Interestingly, the DKO mice were protected from HFD-induced obesity due to their higher energy expenditure and lower expression levels of adipogenic genes (CCAAT/enhancer binding protein α and PPARγ) compared with WT mice. These results together indicate that, compared with Lkb1 or mTOR single KOs, Lkb1/mTOR DKO in adipocytes results in overlapping and distinct metabolic phenotypes, and mTOR KO largely overrides the effect of Lkb1 KO.
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Affiliation(s)
- Yan Xiong
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907; College of Life Science and Technology, Southwest Minzu University, Chengdu, Sichuan 610041, China; Joint Laboratory of Lipid Metabolism, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Beijing 100193, China
| | - Ziye Xu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yizhen Wang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shihuan Kuang
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907; Joint Laboratory of Lipid Metabolism, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Beijing 100193, China.
| | - Tizhong Shan
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; Department of Animal Sciences, Purdue University, West Lafayette, IN 47907.
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Magdalon J, Festuccia WT. Regulation of adiposity by mTORC1. ACTA ACUST UNITED AC 2018; 15:507-511. [PMID: 29364369 PMCID: PMC5875170 DOI: 10.1590/s1679-45082017rb4106] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/20/2017] [Indexed: 11/22/2022]
Abstract
Obesity is characterized by an excessive increase in the adipose tissue mass, and is associated with higher incidence of several chronic metabolic diseases, such as type 2 diabetes. Therefore, its increasing prevalence is a public health concern, and it is important to better understand its etiology to develop new therapeutic strategies. Evidence accumulated over the years indicates that obesity is associated with a marked activation in adipose tissue of the mechanistic target of rapamycin complex 1 (mTORC1), a signaling pathway that controls lipid metabolism, and adipocyte formation and maintenance. Curiously, mTORC1 is also involved in the control of nonshivering thermogenesis and recruitment as well as browning of white adipose tissue. In this review, we explored mTORC1 functions in adipocytes and presented evidence, suggesting that mTORC1 may either increase or reduce adiposity, depending on the conditions and activation levels.
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48
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Liu D, Ceddia RP, Collins S. Cardiac natriuretic peptides promote adipose 'browning' through mTOR complex-1. Mol Metab 2018; 9:192-198. [PMID: 29396369 PMCID: PMC5870104 DOI: 10.1016/j.molmet.2017.12.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Activation of thermogenesis in brown adipose tissue (BAT) and the ability to increase uncoupling protein 1 (UCP1) levels and mitochondrial biogenesis in white fat (termed 'browning'), has great therapeutic potential to treat obesity and its comorbidities because of the net increase in energy expenditure. β-adrenergic-cAMP-PKA signaling has long been known to regulate these processes. Recently PKA-dependent activation of mammalian target of rapamycin complex 1 (mTORC1) was shown to be necessary for adipose 'browning' as well as proper development of the interscapular BAT. In addition to cAMP-PKA signaling pathways, cGMP-PKG signaling also promotes this browning process; however, it is unclear whether or not mTORC1 is also necessary for cGMP-PKG induced browning. METHOD Activation of mTORC1 by natriuretic peptides (NP), which bind to and activate the membrane-bound guanylyl cyclase, NP receptor A (NPRA), was assessed in mouse and human adipocytes in vitro and mouse adipose tissue in vivo. RESULTS Activation of mTORC1 by NP-cGMP signaling was observed in both mouse and human adipocytes. We show that NP-NPRA-PKG signaling activate mTORC1 by direct PKG phosphorylation of Raptor at Serine 791. Administration of B-type natriuretic peptide (BNP) to mice induced Ucp1 expression in inguinal adipose tissue in vivo, which was completely blocked by the mTORC1 inhibitor rapamycin. CONCLUSION Our results demonstrate that NP-cGMP signaling activates mTORC1 via PKG, which is a component in the mechanism of adipose browning.
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Affiliation(s)
- Dianxin Liu
- Integrative Metabolism Program, Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, 6400 Sanger Road, Orlando, FL 32827, USA
| | - Ryan P Ceddia
- Integrative Metabolism Program, Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, 6400 Sanger Road, Orlando, FL 32827, USA
| | - Sheila Collins
- Integrative Metabolism Program, Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, 6400 Sanger Road, Orlando, FL 32827, USA.
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Abdullahi A, Jeschke MG. Taming the Flames: Targeting White Adipose Tissue Browning in Hypermetabolic Conditions. Endocr Rev 2017; 38:538-549. [PMID: 28938469 PMCID: PMC5716828 DOI: 10.1210/er.2017-00163] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/18/2017] [Indexed: 12/17/2022]
Abstract
In this era of increased obesity and diabetes prevalence, the browning of white adipose tissue (WAT) has emerged as a promising therapeutic target to induce weight loss and improve insulin sensitivity in this population. The browning process entails a shift in the WAT from primarily storing excess energy to the dissipation of energy as heat. However, this idealistic view of WAT browning being the savior of the metabolic syndrome has been criticized by studies in burn and cancer patients that have shown browning to be detrimental rather than beneficial. In fact, in the context of hypermetabolic states, the browning of WAT has presented with substantial clinical adverse outcomes related to cachexia, hepatic steatosis, and muscle catabolism. Therefore, the previous thought construct of understanding browning as an all-beneficial physiologic event has now been met with skepticism. In this review, we focus on current knowledge of browning of WAT and its adverse metabolic alterations during hypermetabolic states. We also discuss the regulators and signaling pathways involved in the browning process and their potential for being targeted by new or existing drugs to inhibit or alleviate browning, potentially leading to decreased hypermetabolism and improved clinical outcomes. Lastly, the imminent clinical applications of pharmacological agents are explored in the perspective of attenuating WAT browning and its associated adverse side effects reported in burn patients.
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Affiliation(s)
- Abdikarim Abdullahi
- Faculty of Medicine, University of Toronto, Canada.,Biological Sciences, Sunnybrook Research Institute, Canada.,Ross Tilley Burn Centre, Sunnybrook Hospital, Canada
| | - Marc G Jeschke
- Faculty of Medicine, University of Toronto, Canada.,Biological Sciences, Sunnybrook Research Institute, Canada.,Ross Tilley Burn Centre, Sunnybrook Hospital, Canada.,Department of Surgery, Division of Plastic Surgery and Department of Immunology, University of Toronto, Canada
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50
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mTORC1 Is a Major Regulatory Node in the FGF21 Signaling Network in Adipocytes. Cell Rep 2017; 17:29-36. [PMID: 27681418 DOI: 10.1016/j.celrep.2016.08.086] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/01/2016] [Accepted: 08/24/2016] [Indexed: 11/22/2022] Open
Abstract
FGF21 improves the metabolic profile of obese animals through its actions on adipocytes. To elucidate the signaling network responsible for mediating these effects, we quantified dynamic changes in the adipocyte phosphoproteome following acute exposure to FGF21. FGF21 regulated a network of 821 phosphosites on 542 proteins. A major FGF21-regulated signaling node was mTORC1/S6K. In contrast to insulin, FGF21 activated mTORC1 via MAPK rather than through the canonical PI3K/AKT pathway. Activation of mTORC1/S6K by FGF21 was surprising because this is thought to contribute to deleterious metabolic effects such as obesity and insulin resistance. Rather, mTORC1 mediated many of the beneficial actions of FGF21 in vitro, including UCP1 and FGF21 induction, increased adiponectin secretion, and enhanced glucose uptake without any adverse effects on insulin action. This study provides a global view of FGF21 signaling and suggests that mTORC1 may act to facilitate FGF21-mediated health benefits in vivo.
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