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Jang MH, Song J. Adenosine and adenosine receptors in metabolic imbalance-related neurological issues. Biomed Pharmacother 2024; 177:116996. [PMID: 38897158 DOI: 10.1016/j.biopha.2024.116996] [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: 04/24/2024] [Revised: 06/08/2024] [Accepted: 06/15/2024] [Indexed: 06/21/2024] Open
Abstract
Metabolic syndromes (e.g., obesity) are characterized by insulin resistance, chronic inflammation, impaired glucose metabolism, and dyslipidemia. Recently, patients with metabolic syndromes have experienced not only metabolic problems but also neuropathological issues, including cognitive impairment. Several studies have reported blood-brain barrier (BBB) disruption and insulin resistance in the brain of patients with obesity and diabetes. Adenosine, a purine nucleoside, is known to regulate various cellular responses (e.g., the neuroinflammatory response) by binding with adenosine receptors in the central nervous system (CNS). Adenosine has four known receptors: A1R, A2AR, A2BR, and A3R. These receptors play distinct roles in various physiological and pathological processes in the brain, including endothelial cell homeostasis, insulin sensitivity, microglial activation, lipid metabolism, immune cell infiltration, and synaptic plasticity. Here, we review the recent findings on the role of adenosine receptor-mediated signaling in neuropathological issues related to metabolic imbalance. We highlight the importance of adenosine signaling in the development of therapeutic solutions for neuropathological issues in patients with metabolic syndromes.
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Affiliation(s)
- Mi-Hyeon Jang
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, United States.
| | - Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Hwasun 58128, Republic of Korea.
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2
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Rahman AA, Butcko AJ, Songyekutu E, Granneman JG, Mottillo EP. Direct effects of adipocyte lipolysis on AMPK through intracellular long-chain acyl-CoA signaling. Sci Rep 2024; 14:19. [PMID: 38167670 PMCID: PMC10761689 DOI: 10.1038/s41598-023-50903-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024] Open
Abstract
Long-chain acyl-CoAs (LC-acyl-CoAs) are important intermediary metabolites and are also thought to function as intracellular signaling molecules; however, the direct effects of LC-acyl-CoAs have been difficult to determine in real-time and dissociate from Protein Kinase A (PKA) signaling. Here, we examined the direct role of lipolysis in generating intracellular LC-acyl-CoAs and activating AMPK in white adipocytes by pharmacological activation of ABHD5 (also known as CGI-58), a lipase co-activator. Activation of lipolysis in 3T3-L1 adipocytes independent of PKA with synthetic ABHD5 ligands, resulted in greater activation of AMPK compared to receptor-mediated activation with isoproterenol, a β-adrenergic receptor agonist. Importantly, the effect of pharmacological activation of ABHD5 on AMPK activation was blocked by inhibiting ATGL, the rate-limiting enzyme for triacylglycerol hydrolysis. Utilizing a novel FRET sensor to detect intracellular LC-acyl-CoAs, we demonstrate that stimulation of lipolysis in 3T3-L1 adipocytes increased the production of LC-acyl-CoAs, an effect which was blocked by inhibition of ATGL. Moreover, ATGL inhibition blocked AMPKβ1 S108 phosphorylation, a site required for allosteric regulation. Increasing intracellular LC-acyl-CoAs by removal of BSA in the media and pharmacological inhibition of DGAT1 and 2 resulted in greater activation of AMPK. Finally, inhibiting LC-acyl-CoA generation reduced activation of AMPK; however, did not lower energy charge. Overall, results demonstrate that lipolysis in white adipocytes directly results in allosteric activation of AMPK through the generation of LC-acyl-CoAs.
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Affiliation(s)
- Abir A Rahman
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, 6135 Woodward Ave., Detroit, MI, 48202, USA
| | - Andrew J Butcko
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, 6135 Woodward Ave., Detroit, MI, 48202, USA
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48202, USA
| | - Emmanuel Songyekutu
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48202, USA
| | - James G Granneman
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, 48202, USA
| | - Emilio P Mottillo
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, 6135 Woodward Ave., Detroit, MI, 48202, USA.
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48202, USA.
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3
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Han X, Zhang YL, Lin QY, Li HH, Guo SB. ATGL deficiency aggravates pressure overload-triggered myocardial hypertrophic remodeling associated with the proteasome-PTEN-mTOR-autophagy pathway. Cell Biol Toxicol 2023; 39:2113-2131. [PMID: 35218467 PMCID: PMC10547847 DOI: 10.1007/s10565-022-09699-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 01/26/2022] [Indexed: 11/26/2022]
Abstract
Persistent myocardial hypertrophy frequently leads to heart failure (HF). Intramyocardial triacylglycerol (TAG) accumulation is closely related with cardiac remodeling and abnormal contractile function. Adipose triglyceride lipase (ATGL), a key enzyme in TAG metabolism, regulates cardiac function. However, its associated molecular pathways have not been fully defined. Here, cardiac hypertrophy and HF were induced in wild-type (WT) or ATGL knockout (KO) mice through transverse aortic constriction (TAC) for up to 4 weeks. TAC in WT mice significantly reduced cardiac function and autophagy while enhancing left ventricular hypertrophy, interstitial fibrosis, inflammatory response, superoxide generation, and cardiomyocyte apoptosis, accompanied with upregulation of the proteasome activity, reduction of PTEN level and activation of AKT-mTOR signaling, and these effects were further aggravated in ATGL KO mice. Interestingly, ATGL KO-mediated cardiac dysfunction and remodeling were markedly reversed by proteasome inhibitor (epoxomicin) or autophagic activator (rapamycin), but accelerated by PTEN inhibitor (VO-OHpic) or autophagy inhibitor 3-MA. Mechanistically, ATGL KO upregulated proteasome expression and activity, which in turn mediates PTEN degradation leading to activation of AKT-mTOR signaling and inhibition of autophagy, thereby enhancing hypertrophic remodeling and HF. In conclusion, ATGL KO contributes to TAC-induced cardiac dysfunction and adverse remodeling probably associated with the proteasome-PTEN-mTOR-autophagy pathway. Therefore, modulation of this pathway may have a therapeutic effect potential for hypertrophic heart disease. TAC-induced downregulation of ATGL results in increased proteasome (β1i/β2i/β5i) activity, which in turn promotes degradation of PTEN and activation of AKT-mTOR signaling and then inhibits autophagy and ATP production, thereby leading to cardiac hypertrophic remodeling and dysfunction. Conversely, blocking proteasome activity or activating autophagy attenuates these effects.
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Affiliation(s)
- Xiao Han
- Department of Emergency Medicine, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Yun-Long Zhang
- Department of Emergency Medicine, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Qiu-Yue Lin
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China
| | - Hui-Hua Li
- Department of Emergency Medicine, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China.
| | - Shu-Bin Guo
- Department of Emergency Medicine, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China.
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4
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Townsend LK, Steinberg GR. AMPK and the Endocrine Control of Metabolism. Endocr Rev 2023; 44:910-933. [PMID: 37115289 DOI: 10.1210/endrev/bnad012] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/10/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023]
Abstract
Complex multicellular organisms require a coordinated response from multiple tissues to maintain whole-body homeostasis in the face of energetic stressors such as fasting, cold, and exercise. It is also essential that energy is stored efficiently with feeding and the chronic nutrient surplus that occurs with obesity. Mammals have adapted several endocrine signals that regulate metabolism in response to changes in nutrient availability and energy demand. These include hormones altered by fasting and refeeding including insulin, glucagon, glucagon-like peptide-1, catecholamines, ghrelin, and fibroblast growth factor 21; adipokines such as leptin and adiponectin; cell stress-induced cytokines like tumor necrosis factor alpha and growth differentiating factor 15, and lastly exerkines such as interleukin-6 and irisin. Over the last 2 decades, it has become apparent that many of these endocrine factors control metabolism by regulating the activity of the AMPK (adenosine monophosphate-activated protein kinase). AMPK is a master regulator of nutrient homeostasis, phosphorylating over 100 distinct substrates that are critical for controlling autophagy, carbohydrate, fatty acid, cholesterol, and protein metabolism. In this review, we discuss how AMPK integrates endocrine signals to maintain energy balance in response to diverse homeostatic challenges. We also present some considerations with respect to experimental design which should enhance reproducibility and the fidelity of the conclusions.
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Affiliation(s)
- Logan K Townsend
- Centre for Metabolism Obesity and Diabetes Research, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Gregory R Steinberg
- Centre for Metabolism Obesity and Diabetes Research, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
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5
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Linden MA, Burke SJ, Pirzadah HA, Huang TY, Batdorf HM, Mohammed WK, Jones KA, Ghosh S, Campagna SR, Collier JJ, Noland RC. Pharmacological inhibition of lipolysis prevents adverse metabolic outcomes during glucocorticoid administration. Mol Metab 2023; 74:101751. [PMID: 37295745 PMCID: PMC10300254 DOI: 10.1016/j.molmet.2023.101751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/01/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023] Open
Abstract
OBJECTIVE Glucocorticoids are one of the most commonly prescribed classes of anti-inflammatory drugs; however, chronic treatment promotes iatrogenic (drug-induced) diabetes. As part of their physiological role, glucocorticoids stimulate lipolysis to spare glucose. We hypothesized that persistent stimulation of lipolysis during glucocorticoid therapy plays a causative role in the development of iatrogenic diabetes. METHODS Male C57BL/6J mice were given 100 μg/mL corticosterone (Cort) in the drinking water for two weeks and were fed either normal chow (TekLad 8640) or the same diet supplemented with an adipose triglyceride lipase inhibitor (Atglistatin - 2 g/kg diet) to inhibit the first step of lipolysis. RESULTS Herein, we report for the first time that glucocorticoid administration promotes a unique state of substrate excess and energetic overload in skeletal muscle that primarily results from the rampant mobilization of endogenous fuels. Inhibiting lipolysis protected mice from Cort-induced gains in fat mass, excess ectopic lipid accrual, hyperinsulinemia, and hyperglycemia. The role lipolysis plays in Cort-mediated pathology appears to differ between tissues. Within skeletal muscle, Cort-induced lipolysis facilitated diversion of glucose-derived carbons toward the pentose phosphate and hexosamine biosynthesis pathways but contributed to <3% of the Cort-induced genomic adaptations. In contrast, Cort stimulation of lipolysis accounted for ∼35% of the genomic changes in the liver but had minimal impact on hepatic metabolites reported. CONCLUSIONS These data support the idea that activation of lipolysis plays a causal role in the progression toward iatrogenic diabetes during glucocorticoid therapy with differential impact on skeletal muscle and liver.
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Affiliation(s)
- Melissa A Linden
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA; Department of Exercise and Health Sciences, University of Massachusetts-Boston, Boston, MA, 02125, USA.
| | - Susan J Burke
- Laboratory of Immunogenetics, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
| | - Humza A Pirzadah
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
| | - Tai-Yu Huang
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
| | - Heidi M Batdorf
- Laboratory of Islet Biology and Inflammation, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
| | - Walid K Mohammed
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
| | - Katarina A Jones
- Biological and Small Molecule Mass Spectrometry Core, University of Tennessee, Knoxville, TN, 37916, USA.
| | - Sujoy Ghosh
- Laboratory of Computational Biology, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA; Program in Cardiovascular and Metabolic Disorders and Center for Computational Biology, Duke-National University of Singapore Medical School, Singapore, 169857, Singapore.
| | - Shawn R Campagna
- Biological and Small Molecule Mass Spectrometry Core, University of Tennessee, Knoxville, TN, 37916, USA.
| | - J Jason Collier
- Laboratory of Islet Biology and Inflammation, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
| | - Robert C Noland
- Skeletal Muscle Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA.
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6
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Irisin promotes the browning of white adipocytes tissue by AMPKα1 signaling pathway. Res Vet Sci 2022; 152:270-276. [DOI: 10.1016/j.rvsc.2022.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/30/2022] [Accepted: 08/25/2022] [Indexed: 11/22/2022]
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7
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Kershaw JC, Elzey BD, Guo XX, Kim KH. Piceatannol, a Dietary Polyphenol, Alleviates Adipose Tissue Loss in Pre-Clinical Model of Cancer-Associated Cachexia via Lipolysis Inhibition. Nutrients 2022; 14:nu14112306. [PMID: 35684106 PMCID: PMC9183120 DOI: 10.3390/nu14112306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 12/18/2022] Open
Abstract
Cancer-associated cachexia (CAC) is the nutrition-independent loss of lean muscle and adipose tissues, and results in reduced chemotherapy effectiveness and increased mortality. Preventing adipose loss is considered a key target in the early stages of cachexia. Lipolysis is considered the central driver of adipose loss in CAC. We recently found that piceatannol, but not its analogue resveratrol, exhibits an inhibitory effect on lipolysis. The objective of this study was to investigate the role of piceatannol in cancer-associated lipolysis and cachexia-induced weight loss. Cancer cell-induced lipolysis in adipocytes was stimulated using cancer-conditioned media (CCM) or co-culture with human pancreatic cancer cells and the cachexia-associated cytokines TNF-α and interleukin-6 in 3T3-L1 adipocytes. C26 colon carcinoma-bearing mice were modeled using CAC in vivo. Piceatannol reduced cancer-associated lipolysis by at least 50% in both CCM and cytokine-induced lipolysis in vitro. Further gene and protein analysis confirmed that piceatannol modulated the stability of lipolytic proteins. Moreover, piceatannol protected tumor-bearing mice against weight-loss in early stages of CAC largely through preserving adipose tissue, with no effect on survival. This study demonstrates the use of a dietary compound to preserve adipose in models of early stage CAC and provides groundwork for further investigation of piceatannol or piceatannol-rich foods as alternative medicine in the preservation of body fat mass and future CAC therapy.
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Affiliation(s)
- Jonathan C. Kershaw
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA;
- Department of Public and Allied Health, Bowling Green State University, Bowling Green, OH 43403, USA
| | - Bennett D. Elzey
- Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA;
| | - Xiao-Xuan Guo
- Institute of Quality Standard and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
| | - Kee-Hong Kim
- Department of Food Science, Purdue University, West Lafayette, IN 47907, USA;
- Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA;
- Correspondence: ; Tel.: +1-765-496-2330
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8
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Medak KD, McKie GL, Shamshoum H, Seguin I, Wright DC. The glucose lowering effects of CL 316,243 dissipate with repeated use and are rescued bycilostamide. Physiol Rep 2022; 10:e15187. [PMID: 35179321 PMCID: PMC8855634 DOI: 10.14814/phy2.15187] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 12/22/2022] Open
Abstract
Repeated activation of the beta 3 adrenergic receptor (β3AR) with the agonist CL 316,243 (CL) results in remodeling of white adipose tissue (WAT) characterized by increased mitochondrial enzymes and expression of uncoupling protein 1 (UCP1). β3AR activation also has profound acute metabolic effects including rapidly decreasing blood glucose, secondary to fatty acid-induced increases in insulin, and increasing energy expenditure. The acute (single dose) effects of β3AR activation have largely been examined in treatment naive animals and under room temperature housing conditions. The current study examined if repeated CL treatment would lead to an attenuation of acute metabolic effects of CL treatment under thermoneutral housing conditions and if this could be rescued with cilostamide, a phosphodiesterase inhibitor. We provide evidence demonstrating that the acute effects of CL to increase serum fatty acids and insulin and reduce blood glucose, but not increases in energy expenditure, are attenuated in mice following repeated treatment with CL. This occurs in parallel with reductions in indices of protein kinase A signaling in WAT including the phosphorylation of hormone sensitive lipase. The findings of attenuated serum fatty acid, insulin, and blood glucose responses were confirmed in both high-fat fed and UCP1-/- mice repeatedly treated with CL. Desensitization to CL in mice was rescued by cilostamide. Herein, we provide evidence that the glucose lowering, but not thermogenesis inducing, effects of CL are attenuated with repeated treatment and can be rescued by cilostamide. The findings of this study point toward novel adjunct treatment approaches that could be used to maximize therapeutic, glucose lowering effects of β3AR agonists.
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Affiliation(s)
- Kyle D Medak
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Greg L McKie
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Hesham Shamshoum
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Ian Seguin
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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9
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Boone-Villa D, Ventura-Sobrevilla J, Aguilera-Méndez A, Jiménez-Villarreal J. The effect of adenosine monophosphate-activated protein kinase on lipolysis in adipose tissue: an historical and comprehensive review. Arch Physiol Biochem 2022; 128:7-23. [PMID: 35143739 DOI: 10.1080/13813455.2019.1661495] [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] [Indexed: 10/26/2022]
Abstract
CONTEXT Lipolysis is one of the most important pathways for energy management, its control in the adipose tissue (AT) is a potential therapeutic target for metabolic diseases. Adenosine Mono Phosphate-activated Protein Kinase (AMPK) is a key regulatory enzyme in lipids metabolism and a potential target for diabetes and obesity treatment. OBJECTIVE The aim of this work is to analyse the existing information on the relationship of AMPK and lipolysis in the AT. METHODS A thorough search of bibliography was performed in the databases Scopus and Web of Knowledge using the terms lipolysis, adipose tissue, and AMPK, the unrelated publications were excluded, and the documents were analysed. RESULTS Sixty-three works were found and classified in 3 categories: inhibitory effects, stimulatory effect, and diverse relationships; remarkably, the newest researches support an upregulating relationship of AMPK over lipolysis. CONCLUSION The most probable reality is that the relationship AMPK-lipolysis depends on the experimental conditions.
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Affiliation(s)
- Daniel Boone-Villa
- School of Medicine Northern Unit, Universidad Autonoma de Coahuila, Piedras Negras, México
| | | | - Asdrúbal Aguilera-Méndez
- Institute of Biological Chemistry Research, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, México
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White Adipose Tissue Depots Respond to Chronic Beta-3 Adrenergic Receptor Activation in a Sexually Dimorphic and Depot Divergent Manner. Cells 2021; 10:cells10123453. [PMID: 34943961 PMCID: PMC8700379 DOI: 10.3390/cells10123453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 12/24/2022] Open
Abstract
Beta-3 adrenergic receptor activation via exercise or CL316,243 (CL) induces white adipose tissue (WAT) browning, improves glucose tolerance, and reduces visceral adiposity. Our aim was to determine if sex or adipose tissue depot differences exist in response to CL. Daily CL injections were administered to diet-induced obese male and female mice for two weeks, creating four groups: male control, male CL, female control, and female CL. These groups were compared to determine the main and interaction effects of sex (S), CL treatment (T), and WAT depot (D). Glucose tolerance, body composition, and energy intake and expenditure were assessed, along with perigonadal (PGAT) and subcutaneous (SQAT) WAT gene and protein expression. CL consistently improved glucose tolerance and body composition. Female PGAT had greater protein expression of the mitochondrial uncoupling protein 1 (UCP1), while SQAT (S, p < 0.001) was more responsive to CL in increasing UCP1 (S×T, p = 0.011) and the mitochondrial biogenesis induction protein, PPARγ coactivator 1α (PGC1α) (S×T, p = 0.026). Females also displayed greater mitochondrial OXPHOS (S, p < 0.05) and adiponectin protein content (S, p < 0.05). On the other hand, male SQAT was more responsive to CL in increasing protein levels of PGC1α (S×T, p = 0.046) and adiponectin (S, p < 0.05). In both depots and in both sexes, CL significantly increased estrogen receptor beta (ERβ) and glucose-related protein 75 (GRP75) protein content (T, p < 0.05). Thus, CL improves systemic and adipose tissue-specific metabolism in both sexes; however, sex differences exist in the WAT-specific effects of CL. Furthermore, across sexes and depots, CL affects estrogen signaling by upregulating ERβ.
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Wechman SL, Emdad L, Sarkar D, Das SK, Fisher PB. Vascular mimicry: Triggers, molecular interactions and in vivo models. Adv Cancer Res 2020; 148:27-67. [PMID: 32723566 DOI: 10.1016/bs.acr.2020.06.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Vascular mimicry is induced by a wide array of genes with functions related to cancer stemness, hypoxia, angiogenesis and autophagy. Vascular mimicry competent (VM-competent) cells that form de novo blood vessels are common in solid tumors facilitating tumor cell survival and metastasis. VM-competent cells display increased levels of vascular mimicry selecting for stem-like cells in an O2-gradient-dependent manner in deeply hypoxic tumor regions, while also aiding in maintaining tumor cell metabolism and stemness. Three of the principal drivers of vascular mimicry are EphA2, Nodal and HIF-1α, however, directly or indirectly many of these molecules affect VE-Cadherin (VE-Cad), which forms gap-junctions to bind angiogenic blood vessels together. During vascular mimicry, the endothelial-like functions of VM-competent cancer stem cells co-opt VE-Cad to bind cancer cells together to create cancer cell-derived blood conducting vessels. This process potentially compensates for the lack of access to blood and nutrient in avascular tumors, simultaneously providing nutrients and enhancing cancer invasion and metastasis. Current evidence also supports that vascular mimicry promotes cancer malignancy and metastasis due to the cooperation of oncogenic signaling molecules driving cancer stemness and autophagy. While a number of currently used cancer therapeutics are effective inhibitors of vascular mimicry, developing a new class of vascular mimicry specific inhibitors could allow for the treatment of angiogenesis-resistant tumors, inhibit cancer metastasis and improve patient survival. In this review, we describe the principal vascular mimicry pathways in addition to emphasizing the roles of hypoxia, autophagy and select proangiogenic oncogenes in this process.
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Affiliation(s)
- Stephen L Wechman
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Luni Emdad
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Devanand Sarkar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Swadesh K Das
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.
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12
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Steinberg GR, Carling D. AMP-activated protein kinase: the current landscape for drug development. Nat Rev Drug Discov 2020; 18:527-551. [PMID: 30867601 DOI: 10.1038/s41573-019-0019-2] [Citation(s) in RCA: 383] [Impact Index Per Article: 95.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Since the discovery of AMP-activated protein kinase (AMPK) as a central regulator of energy homeostasis, many exciting insights into its structure, regulation and physiological roles have been revealed. While exercise, caloric restriction, metformin and many natural products increase AMPK activity and exert a multitude of health benefits, developing direct activators of AMPK to elicit beneficial effects has been challenging. However, in recent years, direct AMPK activators have been identified and tested in preclinical models, and a small number have entered clinical trials. Despite these advances, which disease(s) represent the best indications for therapeutic AMPK activation and the long-term safety of such approaches remain to be established.
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Affiliation(s)
- Gregory R Steinberg
- Centre for Metabolism, Obesity and Diabetes Research, Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
| | - David Carling
- Cellular Stress Group, Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London, UK
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13
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Hofer DC, Zirkovits G, Pelzmann HJ, Huber K, Pessentheiner AR, Xia W, Uno K, Miyazaki T, Kon K, Tsuneki H, Pendl T, Al Zoughbi W, Madreiter-Sokolowski CT, Trausinger G, Abdellatif M, Schoiswohl G, Schreiber R, Eisenberg T, Magnes C, Sedej S, Eckhardt M, Sasahara M, Sasaoka T, Nitta A, Hoefler G, Graier WF, Kratky D, Auwerx J, Bogner-Strauss JG. N-acetylaspartate availability is essential for juvenile survival on fat-free diet and determines metabolic health. FASEB J 2019; 33:13808-13824. [PMID: 31638418 PMCID: PMC6894082 DOI: 10.1096/fj.201801323r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/10/2019] [Indexed: 12/15/2022]
Abstract
N-acetylaspartate (NAA) is synthesized by aspartate N-acetyltransferase (gene: Nat8l) from acetyl-coenzyme A and aspartate. In the brain, NAA is considered an important energy metabolite for lipid synthesis. However, the role of NAA in peripheral tissues remained elusive. Therefore, we characterized the metabolic phenotype of knockout (ko) and adipose tissue-specific (ako) Nat8l-ko mice as well as NAA-supplemented mice on various diets. We identified an important role of NAA availability in the brain during adolescence, as 75% of Nat8l-ko mice died on fat-free diet (FFD) after weaning but could be rescued by NAA supplementation. In adult life, NAA deficiency promotes a beneficial metabolic phenotype, as Nat8l-ko and Nat8l-ako mice showed reduced body weight, increased energy expenditure, and improved glucose tolerance on chow, high-fat, and FFDs. Furthermore, Nat8l-deficient adipocytes exhibited increased mitochondrial respiration, ATP synthesis, and an induction of browning. Conversely, NAA-treated wild-type mice showed reduced adipocyte respiration and lipolysis and increased de novo lipogenesis, culminating in reduced energy expenditure, glucose tolerance, and insulin sensitivity. Mechanistically, our data point to a possible role of NAA as modulator of pancreatic insulin secretion and suggest NAA as a critical energy metabolite for adipocyte and whole-body energy homeostasis.-Hofer, D. C., Zirkovits, G., Pelzmann, H. J., Huber, K., Pessentheiner, A. R., Xia, W., Uno, K., Miyazaki, T., Kon, K., Tsuneki, H., Pendl, T., Al Zoughbi, W., Madreiter-Sokolowski, C. T., Trausinger, G., Abdellatif, M., Schoiswohl, G., Schreiber, R., Eisenberg, T., Magnes, C., Sedej, S., Eckhardt, M., Sasahara, M., Sasaoka, T., Nitta, A., Hoefler, G., Graier, W. F., Kratky, D., Auwerx, J., Bogner-Strauss, J. G. N-acetylaspartate availability is essential for juvenile survival on fat-free diet and determines metabolic health.
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Affiliation(s)
- Dina C. Hofer
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Gabriel Zirkovits
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Helmut J. Pelzmann
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Fresenius Kabi Austria GmbH, Graz, Austria
| | - Katharina Huber
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ariane R. Pessentheiner
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Department of Medicine, University of California–San Diego, La Jolla, California, USA
| | - Wenmin Xia
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Kyosuke Uno
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Toh Miyazaki
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Kanta Kon
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Hiroshi Tsuneki
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Tobias Pendl
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Wael Al Zoughbi
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | | | - Gert Trausinger
- Joanneum Research, HEALTH–Institute for Biomedicine and Health Sciences, Graz, Austria
| | | | | | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Christoph Magnes
- Joanneum Research, HEALTH–Institute for Biomedicine and Health Sciences, Graz, Austria
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, University of Bonn, Bonn, Germany
| | | | - Toshiyasu Sasaoka
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Atsumi Nitta
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Gerald Hoefler
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Wolfgang F. Graier
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Juliane G. Bogner-Strauss
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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14
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Townsend LK, Wright DC. Looking on the "brite" side exercise-induced browning of white adipose tissue. Pflugers Arch 2019; 471:455-465. [PMID: 29982948 DOI: 10.1007/s00424-018-2177-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/26/2018] [Accepted: 06/27/2018] [Indexed: 12/17/2022]
Abstract
The need for effective and convenient ways of combatting obesity has created great interest in brown adipose tissue (BAT). However, because adult humans have relatively little amounts of BAT, the possibility of browning white adipose tissue (WAT), i.e., switching the metabolism of WAT from an energy storing to energy burning organ, has gained considerable attention. Exercise has countless health benefits, and has consistently been shown to cause browning in rodent white adipose tissue. The purpose of this review is to provide an overview of recent studies examining the effects of exercise and other interventions on the browning of white adipose tissue. The role of various endocrine factors, including catecholamines, interleukin-6, irisin, and meteorin-like in addition to local re-esterification-mediated mechanisms in inducing the browning of WAT will be discussed. The physiological importance of browning will be discussed, as will discrepancies in the literature between human and rodent studies.
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Affiliation(s)
- Logan K Townsend
- Department of Human Health and Nutritional Science, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada
| | - David C Wright
- Department of Human Health and Nutritional Science, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada.
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15
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Rudnicki M, Abdifarkosh G, Nwadozi E, Ramos SV, Makki A, Sepa-Kishi DM, Ceddia RB, Perry CG, Roudier E, Haas TL. Endothelial-specific FoxO1 depletion prevents obesity-related disorders by increasing vascular metabolism and growth. eLife 2018; 7:39780. [PMID: 30511639 PMCID: PMC6279348 DOI: 10.7554/elife.39780] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/06/2018] [Indexed: 02/07/2023] Open
Abstract
Impaired angiogenesis is a hallmark of metabolically dysfunctional adipose tissue in obesity. However, the underlying mechanisms restricting angiogenesis within this context remain ill-defined. Here, we demonstrate that induced endothelial-specific depletion of the transcription factor Forkhead Box O1 (FoxO1) in male mice led to increased vascular density in adipose tissue. Upon high-fat diet feeding, endothelial cell FoxO1-deficient mice exhibited even greater vascular remodeling in the visceral adipose depot, which was paralleled with a healthier adipose tissue expansion, higher glucose tolerance and lower fasting glycemia concomitant with enhanced lactate levels. Mechanistically, FoxO1 depletion increased endothelial proliferative and glycolytic capacities by upregulating the expression of glycolytic markers, which may account for the improvements at the tissue level ultimately impacting whole-body glucose metabolism. Altogether, these findings reveal the pivotal role of FoxO1 in controlling endothelial metabolic and angiogenic adaptations in response to high-fat diet and a contribution of the endothelium to whole-body energy homeostasis. In the body, thread-like blood vessels called capillaries weave their way through our tissues to deliver oxygen and nutrients to every cell. When a tissue becomes bigger, existing vessels remodel to create new capillaries that can reach far away cells. However, in obesity, this process does not happen the way it should: when fat tissues expand, new blood vessels do not always grow to match. The starved fat cells can start to dysfunction, which causes a range of issues, from inflammation and scarring of the tissues to problems with how the body processes sugar and even diabetes. Yet, it is still unclear why exactly new capillaries fail to form in obesity. What we know is that a protein called FoxO (short for Forkhead box O) is present in the cells that line the inside of blood vessels, and that it can stop the development of new capillaries. FoxO controls how cells spend their energy, and it can force them to go into a resting state. During obesity, the levels of FoxO actually increase in capillary cells. Therefore, it may be possible that FoxO prevents new blood vessels from growing in the fat tissues of obese individuals. To find out, Rudnicki et al. created mice that lack the FoxO protein in the cells lining the capillaries, and then fed the animals a high-fat diet. These mutant mice had more blood vessels in their fat tissue, and their fat cells looked healthier. They also stored less fat than normal mice on the same diet, and their blood sugar levels were normal. This was because the FoxO-deprived cells inside capillaries were burning more energy, which they may have obtained by pulling sugar from the blood. These results show that targeting the cells that line capillaries helps new blood vessels to grow, and that this could mitigate the health problems that arise with obesity, such as high levels of sugar (diabetes) and fat in the blood. However, more work is needed to confirm that the same cellular processes can be targeted to obtain positive health outcomes in humans.
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Affiliation(s)
- Martina Rudnicki
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Ghoncheh Abdifarkosh
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Emmanuel Nwadozi
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Sofhia V Ramos
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Armin Makki
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Diane M Sepa-Kishi
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Rolando B Ceddia
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Christopher Gr Perry
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Emilie Roudier
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
| | - Tara L Haas
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Canada
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16
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Bódis K, Roden M. Energy metabolism of white adipose tissue and insulin resistance in humans. Eur J Clin Invest 2018; 48:e13017. [PMID: 30107041 DOI: 10.1111/eci.13017] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 07/22/2018] [Accepted: 08/12/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND Insulin resistance not only occurs in obesity, but also in lipodystrophy. Although adipose tissue mass affects metabolic fluxes and participates in interorgan crosstalk, the role of energy metabolism within white adipose tissue for insulin resistance is less clear. MATERIALS AND METHODS A Medline search identified in vivo studies in humans on energy and lipid metabolism in subcutaneous (SAT) and visceral adipose tissue (VAT). Studies in adipocyte cultures and transgenic animal models were included for the better understanding of the link between abnormal energy metabolism in adipose tissue and insulin resistance. RESULTS The current literature indicates that higher lipolysis and lower lipogenesis in VAT compared to SAT enhance portal delivery of lipid metabolites (glycerol and fatty acids) to the liver. Thus, the lower lipolysis and higher lipogenesis in SAT favour storage of excess lipids and allow for protection of insulin-sensitive tissues from lipotoxic effects. In insulin-resistant humans, enhanced lipolysis and impaired lipogenesis in adipose tissue lead to release of cytokines and lipid metabolites, ultimately promoting insulin resistance. Adipose tissue of insulin-resistant humans also displays lower expression of proteins involved in mitochondrial function. In turn, this leads to lower availability of mitochondria-derived energy sources for lipogenesis in adipose tissue. CONCLUSIONS Abnormal mitochondrial function in human white adipose tissue likely contributes to the secretion of lipid metabolites and lactate, which are linked to insulin resistance in peripheral tissues. However, the relevance of adipose tissue energy metabolism for the regulation of human insulin sensitivity remains to be further elucidated.
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Affiliation(s)
- Kálmán Bódis
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany.,Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany.,German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Michael Roden
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany.,Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany.,German Center for Diabetes Research (DZD), München-Neuherberg, Germany
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17
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Desjardins EM, Steinberg GR. Emerging Role of AMPK in Brown and Beige Adipose Tissue (BAT): Implications for Obesity, Insulin Resistance, and Type 2 Diabetes. Curr Diab Rep 2018; 18:80. [PMID: 30120579 DOI: 10.1007/s11892-018-1049-6] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW The global prevalence of type 2 diabetes (T2D) is escalating at alarming rates, demanding the development of additional classes of therapeutics to further reduce the burden of disease. Recent studies have indicated that increasing the metabolic activity of brown and beige adipose tissue may represent a novel means to reduce circulating glucose and lipids in people with T2D. The AMP-activated protein kinase (AMPK) is a cellular energy sensor that has recently been demonstrated to be important in potentially regulating the metabolic activity of brown and beige adipose tissue. The goal of this review is to summarize recent work describing the role of AMPK in brown and beige adipose tissue, focusing on its role in adipogenesis and non-shivering thermogenesis. RECENT FINDINGS Ablation of AMPK in mouse adipocytes results in cold intolerance, a reduction in non-shivering thermogenesis in brown adipose tissue (BAT), and the development of non-alcoholic fatty liver disease (NAFLD) and insulin resistance; effects associated with a defect in mitochondrial specific autophagy (mitophagy) within BAT. The effects of a β3-adrenergic agonist on the induction of BAT thermogenesis and the browning of white adipose tissue (WAT) are also blunted in mice lacking adipose tissue AMPK. A specific AMPK activator, A-769662, also results in the activation of BAT and the browning of WAT, effects which may involve demethylation of the PR domain containing 16 (Prdm16) promoter region, which is important for BAT development. AMPK plays an important role in the development and maintenance of brown and beige adipose tissue. Adipose tissue AMPK is reduced in people with insulin resistance, consistent with findings that mice lacking adipocyte AMPK develop greater NAFLD and insulin resistance. These data suggest that pharmacologically targeting adipose tissue AMPK may represent a promising strategy to enhance energy expenditure and reduce circulating glucose and lipids, which may be effective for the treatment of NAFLD and T2D.
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Affiliation(s)
- Eric M Desjardins
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8N 3Z5, Canada
| | - Gregory R Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8N 3Z5, Canada.
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8N 3Z5, Canada.
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18
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Abstract
The AMP-activated protein kinase (AMPK) is a central regulator of multiple metabolic pathways and may have therapeutic importance for treating obesity, insulin resistance, type 2 diabetes (T2D), non-alcoholic fatty liver disease (NAFLD), and cardiovascular disease (CVD). Given the ubiquitous expression of AMPK, it has been a challenge to evaluate which tissue types may be most beneficially poised for mediating the positive metabolic effects of AMPK-centered treatments. In this review we evaluate the metabolic phenotypes of transgenic mouse models in which AMPK expression and function have been manipulated, and the impact this has on controlling lipid metabolism, glucose homeostasis, and inflammation. This information may be useful for guiding the development of AMPK-targeted therapeutics to treat chronic metabolic diseases.
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Affiliation(s)
- Emily A Day
- Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON, Canada
| | - Rebecca J Ford
- Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON, Canada
| | - Gregory R Steinberg
- Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, ON, Canada; Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, ON, Canada.
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19
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Dragos SM, Bergeron KF, Desmarais F, Suitor K, Wright DC, Mounier C, Mutch DM. Reduced SCD1 activity alters markers of fatty acid reesterification, glyceroneogenesis, and lipolysis in murine white adipose tissue and 3T3-L1 adipocytes. Am J Physiol Cell Physiol 2017; 313:C295-C304. [PMID: 28659287 DOI: 10.1152/ajpcell.00097.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 06/21/2017] [Accepted: 06/23/2017] [Indexed: 11/22/2022]
Abstract
White adipose tissue (WAT) has a critical role in lipid handling. Previous work demonstrated that SCD1 is an important regulator of WAT fatty acid (FA) composition; however, its influence on the various interconnected pathways influencing WAT lipid handling remains unclear. Our objective was to investigate the role of SCD1 on WAT lipid handling using Scd1 knockout (KO) mice and SCD1-inhibited 3T3-L1 adipocytes by measuring gene, protein, and metabolite markers related to FA reesterification, glyceroneogenesis, and lipolysis. Triacylglycerol (TAG) content was higher in inguinal WAT (iWAT) from KO mice compared with wild-type, but significantly lower in epididymal WAT (eWAT). The SCD1 desaturation index was decreased in both WAT depots in KO mice. FA reesterification, as measured with a NEFA:glycerol ratio, was reduced in both WAT depots in KO mice, as well as SCD1-inhibited 3T3-L1 adipocytes. Pck1, Atgl, and Hsl gene expression was reduced in both WAT depots of KO mice, while Pck2 and Pdk4 gene expression showed depot-specific regulation. Pck1, Atgl, and Hsl gene expression was reduced, and phosphoenolpyruvate carboxykinase protein content was ablated, in SCD1-inhibited adipocytes. Our data provide evidence that SCD1 has a broad impact on WAT lipid handling by altering TAG composition in a depot-specific manner, reducing FA reesterification, and regulating markers of lipolysis and glyceroneogenesis.
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Affiliation(s)
- Steven M Dragos
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - Karl F Bergeron
- Département des sciences biologiques et centre de recherche BioMed, Université du Québec à Montréal, Montreal, Quebec, Canada
| | - Frédérik Desmarais
- Département des sciences biologiques et centre de recherche BioMed, Université du Québec à Montréal, Montreal, Quebec, Canada
| | - Katherine Suitor
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - David C Wright
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - Catherine Mounier
- Département des sciences biologiques et centre de recherche BioMed, Université du Québec à Montréal, Montreal, Quebec, Canada
| | - David M Mutch
- Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada; and
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20
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Leiva A, Guzmán-Gutiérrez E, Contreras-Duarte S, Fuenzalida B, Cantin C, Carvajal L, Salsoso R, Gutiérrez J, Pardo F, Sobrevia L. Adenosine receptors: Modulators of lipid availability that are controlled by lipid levels. Mol Aspects Med 2017; 55:26-44. [DOI: 10.1016/j.mam.2017.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
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21
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Townsend LK, Knuth CM, Wright DC. Cycling our way to fit fat. Physiol Rep 2017; 5:5/7/e13247. [PMID: 28404813 PMCID: PMC5392531 DOI: 10.14814/phy2.13247] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/10/2017] [Accepted: 03/16/2017] [Indexed: 12/25/2022] Open
Abstract
Adipose tissue is increasingly being recognized as a key regulator of whole body carbohydrate and lipid metabolism. In conditions of obesity and insulin resistance mitochondrial content in this tissue is reduced, while treatment with insulin sensitizing drugs such as thiazolidinediones (TZDs) increase mitochondrial content. It has been known for decades that exercise increases mitochondrial content in skeletal muscle and now several laboratories have shown similar effects in adipose tissue. To date the specific mechanisms mediating this effect have not been fully identified. In this review we highlight recent work suggesting that increases in lipolysis and subsequently fatty acid re‐esterification trigger the activation of 5' AMP‐activated protein kinase (AMP) activated protein kinase and ultimately the induction of mitochondrial biogenesis. It is our current view that this pathway could be a unifying mechanism linking numerous systemic factors (catecholamines, interleukin‐6, meteorin‐like) to induction of mitochondrial biogenesis following exercise.
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Affiliation(s)
- Logan K Townsend
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, Canada
| | - Carly M Knuth
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, Canada
| | - David C Wright
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, Canada
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22
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Flachs P, Adamcova K, Zouhar P, Marques C, Janovska P, Viegas I, Jones JG, Bardova K, Svobodova M, Hansikova J, Kuda O, Rossmeisl M, Liisberg U, Borkowska AG, Kristiansen K, Madsen L, Kopecky J. Induction of lipogenesis in white fat during cold exposure in mice: link to lean phenotype. Int J Obes (Lond) 2016; 41:372-380. [PMID: 28008171 DOI: 10.1038/ijo.2016.228] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 11/10/2016] [Accepted: 11/24/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND/OBJECTIVE Futile substrate cycling based on lipolytic release of fatty acids (FA) from intracellular triacylglycerols (TAG) and their re-esterification (TAG/FA cycling), as well as de novo FA synthesis (de novo lipogenesis (DNL)), represent the core energy-consuming biochemical activities of white adipose tissue (WAT). We aimed to characterize their roles in cold-induced thermogenesis and energy homeostasis. METHODS Male obesity-resistant A/J and obesity-prone C57BL/6J mice maintained at 30 °C were exposed to 6 °C for 2 or 7 days. In epididymal WAT (eWAT), TAG synthesis and DNL were determined using in vivo 2H incorporation from 2H2O into tissue TAG and nuclear magnetic resonance spectroscopy. Quantitative real-time-PCR and/or immunohistochemistry and western blotting were used to determine the expression of selected genes and proteins in WAT and liver. RESULTS The mass of WAT depots declined during cold exposure (CE). Plasma levels of TAG and non-esterified FA were decreased by day 2 but tended to normalize by day 7 of CE. TAG synthesis (reflecting TAG/FA cycle activity) gradually increased during CE. DNL decreased by day 2 of CE but increased several fold over the control values by day 7. Expression of genes involved in lipolysis, glyceroneogenesis, FA re-esterification, FA oxidation and mitochondrial biogenesis in eWAT was induced during CE. All these changes were more pronounced in obesity-resistant A/J than in B6 mice and occurred in the absence of uncoupling protein 1 in eWAT. Expression of markers of glyceroneogenesis in eWAT correlated negatively with hepatic FA synthesis by day 7 in both strains. Leptin and fibroblast growth factor 21 plasma levels were differentially affected by CE in the two mouse strains. CONCLUSIONS Our results indicate integrated involvement of (i) TAG/FA cycling and DNL in WAT, and (ii) hepatic very-low-density lipoprotein-TAG synthesis in the control of blood lipid levels and provision of FA fuels for thermogenesis in cold. They suggest that lipogenesis in WAT contributes to a lean phenotype.
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Affiliation(s)
- P Flachs
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - K Adamcova
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - P Zouhar
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - C Marques
- Centre for Neuroscience and Cell Biology, University of Coimbra, Cantanhede, Portugal
| | - P Janovska
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - I Viegas
- Centre for Neuroscience and Cell Biology, University of Coimbra, Cantanhede, Portugal
| | - J G Jones
- Centre for Neuroscience and Cell Biology, University of Coimbra, Cantanhede, Portugal
| | - K Bardova
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - M Svobodova
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - J Hansikova
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - O Kuda
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - M Rossmeisl
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - U Liisberg
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,National Institute of Nutrition and Seafood Research, Bergen, Norway
| | - A G Borkowska
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - K Kristiansen
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,BGI-Shenzhen, Shenzhen, China
| | - L Madsen
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,National Institute of Nutrition and Seafood Research, Bergen, Norway
| | - J Kopecky
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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Zhang Z, Zhao S, Yao Z, Wang L, Shao J, Chen A, Zhang F, Zheng S. Autophagy regulates turnover of lipid droplets via ROS-dependent Rab25 activation in hepatic stellate cell. Redox Biol 2016; 11:322-334. [PMID: 28038427 PMCID: PMC5199192 DOI: 10.1016/j.redox.2016.12.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/19/2016] [Accepted: 12/19/2016] [Indexed: 12/22/2022] Open
Abstract
Activation of hepatic stellate cells (HSCs) is a pivotal event in liver fibrosis, characterized by dramatic disappearance of lipid droplets (LDs). Although LD disappearance has long been considered one of the hallmarks of HSC activation, the underlying molecular mechanisms are largely unknown. In this study, we sought to investigate the role of autophagy in the process of LD disappearance, and to further examine the underlying mechanisms in this molecular context. We found that LD disappearance during HSC activation was associated with a coordinate increase in autophagy. Inhibition or depletion of autophagy by Atg5 siRNA impaired LD disappearance of quiescent HSCs, and also restored lipocyte phenotype of activated HSCs. In contrast, induction of autophagy by Atg5 plasmid accelerated LD loss of quiescent HSCs. Importantly, our study also identified a crucial role for reactive oxygen species (ROS) in the facilitation of autophagy activation. Antioxidants, such as glutathione and N-acetyl cysteine, significantly abrogated ROS production, and in turn, prevented autophagosome generation and autophagic flux during HSC activation. Besides, we found that HSC activation triggered Rab25 overexpression, and promoted the combination of Rab25 and PI3KCIII, which direct autophagy to recognize, wrap and degrade LDs. Down-regulation of Rab25 activity, using Rab25 siRNA, blocked the target recognition of autophagy on LDs, and inhibited LD disappearance of quiescent HSCs. Moreover, the scavenging of excessive ROS could disrupt the interaction between autophagy and Rab25, and increase intracellular lipid content. Overall, these results provide novel implications to reveal the molecular mechanism of LD disappearance during HSC activation, and also identify ROS-Rab25-dependent autophagy as a potential target for the treatment of liver fibrosis. Autophagosome generation and autophagic flux are increased during HSC activation. The inhibition of autophagy blocks LD disappearance of quiescent HSCs. The induction of autophagy accelerates LD disappearance of quiescent HSCs. Rab25 activation is required for autophagy to degrade LDs during HSC activation. Mitochondrial H2O2 production triggers autophagy activation during HSC activation.
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Affiliation(s)
- Zili Zhang
- Department of Pharmacology, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China
| | - Shifeng Zhao
- Department of Pharmacology, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China
| | - Zhen Yao
- Department of Pharmacology, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China
| | - Ling Wang
- Department of Pharmacology, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China
| | - Jiangjuan Shao
- Department of Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China
| | - Anping Chen
- Department of Pathology, School of Medicine, Saint Louis University, St Louis., MO 63104, USA
| | - Feng Zhang
- Department of Pharmacology, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China
| | - Shizhong Zheng
- Department of Pharmacology, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, PR China.
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