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Guan H, Xiao L, Hao K, Zhang Q, Wu D, Geng Z, Duan B, Dai H, Xu R, Feng X. SLC25A28 Overexpression Promotes Adipogenesis by Reducing ATGL. J Diabetes Res 2024; 2024:5511454. [PMID: 38736904 PMCID: PMC11088465 DOI: 10.1155/2024/5511454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 03/21/2024] [Accepted: 03/26/2024] [Indexed: 05/14/2024] Open
Abstract
Adipose tissue dysfunction is seen among obese and type 2 diabetic individuals. Adipocyte proliferation and hypertrophy are the root causes of adipose tissue expansion. Solute carrier family 25 member 28 (SLC25A28) is an iron transporter in the inner mitochondrial membrane. This study is aimed at validating the involvement of SLC25A28 in adipose accumulation by tail vein injection of adenovirus (Ad)-SLC25A28 and Ad-green fluorescent protein viral particles into C57BL/6J mice. After 16 weeks, the body weight of the mice was measured. Subsequently, morphological analysis was performed to establish a high-fat diet (HFD)-induced model. SLC25A28 overexpression accelerated lipid accumulation in white and brown adipose tissue (BAT), enhanced body weight, reduced serum triglyceride (TG), and impaired serum glucose tolerance. The protein expression level of lipogenesis, lipolysis, and serum adipose secretion hormone was evaluated by western blotting. The results showed that adipose TG lipase (ATGL) protein expression was reduced significantly in white and BAT after overexpression SLC25A28 compared to the control group. Moreover, SLC25A28 overexpression inhibited the BAT formation by downregulating UCP-1 and the mitochondrial biosynthesis marker PGC-1α. Serum adiponectin protein expression was unregulated, which was consistent with the expression in inguinal white adipose tissue (iWAT). Remarkably, serum fibroblast growth factor (FGF21) protein expression was negatively related to the expansion of adipose tissue after administrated by Ad-SLC25A28. Data from the current study indicate that SLC25A28 overexpression promotes diet-induced obesity and accelerates lipid accumulation by regulating hormone secretion and inhibiting lipolysis in adipose tissue.
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Affiliation(s)
- Hua Guan
- Shaanxi Key Laboratory of Ischemic Cardiovascular Diseases & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an 710021, Shaanxi, China
| | - Lin Xiao
- Shaanxi Key Laboratory of Ischemic Cardiovascular Diseases & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an 710021, Shaanxi, China
| | - Kaikai Hao
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - Qiang Zhang
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - Dongliang Wu
- Department of Cardiology, Xianyang Hospital of Yan'an University, Xianyang 712000, China
| | - Zhanyi Geng
- Shaanxi Key Laboratory of Ischemic Cardiovascular Diseases & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an 710021, Shaanxi, China
| | - Bowen Duan
- Shaanxi Key Laboratory of Ischemic Cardiovascular Diseases & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an 710021, Shaanxi, China
| | - Hui Dai
- Department of Clinical Medicine, Gansu Medical College, Pingliang 744000, China
| | - Ruifen Xu
- Department of Anesthesiology, Shaanxi Provincial Peoples Hospital, Xi'an 710068, China
| | - Xuyang Feng
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
- Department of Neurology, Xianyang Hospital of Yan'an University, Xianyang 712000, China
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2
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Dietzsch AN, Al-Hasani H, Altschmied J, Bottermann K, Brendler J, Haendeler J, Horn S, Kaczmarek I, Körner A, Krause K, Landgraf K, Le Duc D, Lehmann L, Lehr S, Pick S, Ricken A, Schnorr R, Schulz A, Strnadová M, Velluva A, Zabri H, Schöneberg T, Thor D, Prömel S. Dysfunction of the adhesion G protein-coupled receptor latrophilin 1 (ADGRL1/LPHN1) increases the risk of obesity. Signal Transduct Target Ther 2024; 9:103. [PMID: 38664368 PMCID: PMC11045723 DOI: 10.1038/s41392-024-01810-7] [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: 08/21/2023] [Revised: 03/04/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024] Open
Abstract
Obesity is one of the diseases with severe health consequences and rapidly increasing worldwide prevalence. Understanding the complex network of food intake and energy balance regulation is an essential prerequisite for pharmacological intervention with obesity. G protein-coupled receptors (GPCRs) are among the main modulators of metabolism and energy balance. They, for instance, regulate appetite and satiety in certain hypothalamic neurons, as well as glucose and lipid metabolism and hormone secretion from adipocytes. Mutations in some GPCRs, such as the melanocortin receptor type 4 (MC4R), have been associated with early-onset obesity. Here, we identified the adhesion GPCR latrophilin 1 (ADGRL1/LPHN1) as a member of the regulating network governing food intake and the maintenance of energy balance. Deficiency of the highly conserved receptor in mice results in increased food consumption and severe obesity, accompanied by dysregulation of glucose homeostasis. Consistently, we identified a partially inactivating mutation in human ADGRL1/LPHN1 in a patient suffering from obesity. Therefore, we propose that LPHN1 dysfunction is a risk factor for obesity development.
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Affiliation(s)
- André Nguyen Dietzsch
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Hadi Al-Hasani
- Institute for Clinical Biochemistry and Pathobiochemistry, Medical Faculty, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Munich-Neuherberg, Germany
| | - Joachim Altschmied
- Cardiovascular Degeneration, Clinical Chemistry and Laboratory Diagnostics, Medical Faculty, University Hospital and Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Cardiovascular Research Institute (CARID), Medical Faculty, University Hospital and Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Katharina Bottermann
- Cardiovascular Research Institute (CARID), Medical Faculty, University Hospital and Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Pharmacology, Medical Faculty, University Hospital and Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jana Brendler
- Institute of Anatomy, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Judith Haendeler
- Cardiovascular Degeneration, Clinical Chemistry and Laboratory Diagnostics, Medical Faculty, University Hospital and Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Cardiovascular Research Institute (CARID), Medical Faculty, University Hospital and Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Susanne Horn
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Isabell Kaczmarek
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Antje Körner
- Center for Pediatric Research, Hospital for Children and Adolescents, Medical Faculty, Leipzig University, Leipzig, Germany
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany
| | - Kerstin Krause
- Department of Endocrinology, Nephrology, Rheumatology, Leipzig University Medical Center, Leipzig, Germany
| | - Kathrin Landgraf
- Center for Pediatric Research, Hospital for Children and Adolescents, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Diana Le Duc
- Institute of Human Genetics, Leipzig University Medical Center, Leipzig, Germany
| | - Laura Lehmann
- Institute of Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stefan Lehr
- Institute for Clinical Biochemistry and Pathobiochemistry, Medical Faculty, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Munich-Neuherberg, Germany
| | - Stephanie Pick
- Institute of Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Albert Ricken
- Institute of Anatomy, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Rene Schnorr
- Institute of Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Angela Schulz
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Martina Strnadová
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Akhil Velluva
- Institute of Human Genetics, Leipzig University Medical Center, Leipzig, Germany
| | - Heba Zabri
- Institute of Pharmacology, Medical Faculty, University Hospital and Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
- School of Medicine, University of Global Health Equity, Kigali, Rwanda
| | - Doreen Thor
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany.
| | - Simone Prömel
- Institute of Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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Qi W, Fang Z, Luo C, Hong H, Long Y, Dai Z, Liu J, Zeng Y, Zhou T, Xia Y, Yang X, Gao G. The critical role of BTRC in hepatic steatosis as an ATGL E3 ligase. J Mol Cell Biol 2024; 15:mjad064. [PMID: 37873692 PMCID: PMC10993717 DOI: 10.1093/jmcb/mjad064] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 05/26/2023] [Accepted: 10/20/2023] [Indexed: 10/25/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD), characterized by hepatic steatosis, is one of the commonest causes of liver dysfunction. Adipose triglyceride lipase (ATGL) is closely related to lipid turnover and hepatic steatosis as the speed-limited triacylglycerol lipase in liver lipolysis. However, the expression and regulation of ATGL in NAFLD remain unclear. Herein, our results showed that ATGL protein levels were decreased in the liver tissues of high-fat diet (HFD)-fed mice, naturally obese mice, and cholangioma/hepatic carcinoma patients with hepatic steatosis, as well as in the oleic acid-induced hepatic steatosis cell model, while ATGL mRNA levels were not changed. ATGL protein was mainly degraded through the proteasome pathway in hepatocytes. Beta-transducin repeat containing (BTRC) was upregulated and negatively correlated with the decreased ATGL level in these hepatic steatosis models. Consequently, BTRC was identified as the E3 ligase for ATGL through predominant ubiquitination at the lysine 135 residue. Moreover, adenovirus-mediated knockdown of BTRC ameliorated steatosis in HFD-fed mouse livers and oleic acid-treated liver cells via upregulating the ATGL level. Taken together, BTRC plays a crucial role in hepatic steatosis as a new ATGL E3 ligase and may serve as a potential therapeutic target for treating NAFLD.
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Affiliation(s)
- Weiwei Qi
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Zhenzhen Fang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Chuanghua Luo
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Honghai Hong
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
- Department of Clinical Laboratory, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510006, China
| | - Yanlan Long
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Zhiyu Dai
- Department of Internal Medicine, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Junxi Liu
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Yongcheng Zeng
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Ti Zhou
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Yong Xia
- Department of Clinical Laboratory, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510006, China
| | - Xia Yang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
- Guangdong Engineering & Technology Research Center for Gene Manipulation and Biomacromolecular Products, Sun Yat-sen University, Guangzhou 510080, China
| | - Guoquan Gao
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
- Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
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4
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Ghesmati Z, Rashid M, Fayezi S, Gieseler F, Alizadeh E, Darabi M. An update on the secretory functions of brown, white, and beige adipose tissue: Towards therapeutic applications. Rev Endocr Metab Disord 2024; 25:279-308. [PMID: 38051471 PMCID: PMC10942928 DOI: 10.1007/s11154-023-09850-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/30/2023] [Indexed: 12/07/2023]
Abstract
Adipose tissue, including white adipose tissue (WAT), brown adipose tissue (BAT), and beige adipose tissue, is vital in modulating whole-body energy metabolism. While WAT primarily stores energy, BAT dissipates energy as heat for thermoregulation. Beige adipose tissue is a hybrid form of adipose tissue that shares characteristics with WAT and BAT. Dysregulation of adipose tissue metabolism is linked to various disorders, including obesity, type 2 diabetes, cardiovascular diseases, cancer, and infertility. Both brown and beige adipocytes secrete multiple molecules, such as batokines, packaged in extracellular vesicles or as soluble signaling molecules that play autocrine, paracrine, and endocrine roles. A greater understanding of the adipocyte secretome is essential for identifying novel molecular targets in treating metabolic disorders. Additionally, microRNAs show crucial roles in regulating adipose tissue differentiation and function, highlighting their potential as biomarkers for metabolic disorders. The browning of WAT has emerged as a promising therapeutic approach in treating obesity and associated metabolic disorders. Many browning agents have been identified, and nanotechnology-based drug delivery systems have been developed to enhance their efficacy. This review scrutinizes the characteristics of and differences between white, brown, and beige adipose tissues, the molecular mechanisms involved in the development of the adipocytes, the significant roles of batokines, and regulatory microRNAs active in different adipose tissues. Finally, the potential of WAT browning in treating obesity and atherosclerosis, the relationship of BAT with cancer and fertility disorders, and the crosstalk between adipose tissue with circadian system and circadian disorders are also investigated.
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Affiliation(s)
- Zeinab Ghesmati
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohsen Rashid
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Shabnam Fayezi
- Department of Gynecologic Endocrinology and Fertility Disorders, Women's Hospital, Ruprecht-Karls University of Heidelberg, Heidelberg, Germany
| | - Frank Gieseler
- Division of Experimental Oncology, Department of Hematology and Oncology, University Medical Center Schleswig-Holstein, Campus Lübeck, 23538, Lübeck, Germany
| | - Effat Alizadeh
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Masoud Darabi
- Division of Experimental Oncology, Department of Hematology and Oncology, University Medical Center Schleswig-Holstein, Campus Lübeck, 23538, Lübeck, Germany.
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5
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Lu JF, Zhu MQ, Xia B, Zhang NN, Liu XP, Liu H, Zhang RX, Xiao JY, Yang H, Zhang YQ, Li XM, Wu JW. GDF15 is a major determinant of ketogenic diet-induced weight loss. Cell Metab 2023; 35:2165-2182.e7. [PMID: 38056430 DOI: 10.1016/j.cmet.2023.11.003] [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: 01/31/2023] [Revised: 07/27/2023] [Accepted: 11/10/2023] [Indexed: 12/08/2023]
Abstract
A ketogenic diet (KD) has been promoted as an obesity management diet, yet its underlying mechanism remains elusive. Here we show that KD reduces energy intake and body weight in humans, pigs, and mice, accompanied by elevated circulating growth differentiation factor 15 (GDF15). In GDF15- or its receptor GFRAL-deficient mice, these effects of KD disappeared, demonstrating an essential role of GDF15-GFRAL signaling in KD-mediated weight loss. Gdf15 mRNA level increases in hepatocytes upon KD feeding, and knockdown of Gdf15 by AAV8 abrogated the obesity management effect of KD in mice, corroborating a hepatic origin of GDF15 production. We show that KD activates hepatic PPARγ, which directly binds to the regulatory region of Gdf15, increasing its transcription and production. Hepatic Pparγ-knockout mice show low levels of plasma GDF15 and significantly diminished obesity management effects of KD, which could be restored by either hepatic Gdf15 overexpression or recombinant GDF15 administration. Collectively, our study reveals a previously unexplored GDF15-dependent mechanism underlying KD-mediated obesity management.
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Affiliation(s)
- Jun Feng Lu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Meng Qing Zhu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Bo Xia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Na Na Zhang
- Department of Endocrinology and Metabolism, First Affiliated Hospital of Air Force Medical University, Xi'an, Shaanxi 710032, China
| | - Xiao Peng Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Huan Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Rui Xin Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jun Ying Xiao
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Hui Yang
- National Health Commission (NHC) Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100022, China
| | - Ying Qi Zhang
- State Key Laboratory of Cancer Biology, Biotechnology Center, School of Pharmacy, Air Force Medical University, Xi'an, Shaanxi 710032, China
| | - Xiao Miao Li
- Department of Endocrinology and Metabolism, First Affiliated Hospital of Air Force Medical University, Xi'an, Shaanxi 710032, China.
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China.
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6
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Zakaria Z, Othman ZA, Nna VU, Mohamed M. The promising roles of medicinal plants and bioactive compounds on hepatic lipid metabolism in the treatment of non-alcoholic fatty liver disease in animal models: molecular targets. Arch Physiol Biochem 2023; 129:1262-1278. [PMID: 34153200 DOI: 10.1080/13813455.2021.1939387] [Citation(s) in RCA: 2] [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] [Received: 09/11/2020] [Accepted: 06/01/2021] [Indexed: 12/13/2022]
Abstract
Imbalance in hepatic lipid metabolism can lead to an abnormal triglycerides deposition in the hepatocytes which can cause non-alcoholic fatty liver disease (NAFLD). Four main mechanisms responsible for regulating hepatic lipid metabolism are fatty acid uptake, de novo lipogenesis, lipolysis and fatty acid oxidation. Controlling the expression of transcription factors at molecular level plays a crucial role in NAFLD management. This paper reviews various medicinal plants and their bioactive compounds emphasising mechanisms involved in hepatic lipid metabolism, other important NAFLD pathological features, and their promising roles in managing NAFLD through regulating key transcription factors. Although there are many medicinal plants popularly investigated for NAFLD treatment, there is still little information and scientific evidence available and there has been no research on clinical trials scrutinised on this matter. This review also aims to provide molecular information of medicinal plants in NALFD treatment that might have potentials for future scientifically controlled studies.
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Affiliation(s)
- Zaida Zakaria
- Department of Physiology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Zaidatul Akmal Othman
- Department of Physiology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kelantan, Malaysia
- Unit of Physiology, Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu, Malaysia
| | - Victor Udo Nna
- Department of Physiology, Faculty of Basic Medical Sciences, College of Medical Sciences, University of Calabar, Calabar, Nigeria
| | - Mahaneem Mohamed
- Department of Physiology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kelantan, Malaysia
- Unit of Integrative Medicine, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kelantan, Malaysia
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Klobučar I, Hinteregger H, Lechleitner M, Trbušić M, Pregartner G, Berghold A, Sattler W, Frank S, Degoricija V. Association between Serum Free Fatty Acids and Clinical and Laboratory Parameters in Acute Heart Failure Patients. Biomedicines 2023; 11:3197. [PMID: 38137418 PMCID: PMC10740773 DOI: 10.3390/biomedicines11123197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/14/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
Very little is known about the association between individual serum free fatty acids (FFAs) and clinical and laboratory parameters (indicators of heart failure severity) in acute heart failure (AHF) patients. Here, the baseline serum levels of FFAs, 16:0 (palmitic acid), 16:1 (palmitoleic acid), 18:0 (stearic acid), 18:1 (oleic acid), 18:2 (linoleic acid), 18:3 (alpha-linolenic acid or gamma-linolenic acid), 20:4 (arachidonic acid), 20:5 (eicosapentaenoic acid), and 22:6 (docosahexaenoic acid), were determined in 304 AHF patients (94.7% belonged to New York Heart Association functional class IV) using gas chromatography. Spearman correlation coefficients were used to examine the associations between the individual and total (the sum of all FFAs) FFAs and clinical and laboratory parameters. After applying a Bonferroni correction to correct for multiple testing, the total FFAs, as well as the individual FFAs (except FFAs 18:0, 20:5, and 22:6), were found to be significantly positively correlated with serum albumin. Only a few additional associations were found: FFA 16:0 was significantly negatively correlated with systolic pulmonary artery pressure, FFA 18:3 was significantly negatively correlated with C-reactive protein and body mass index, and FFA 20:4 was significantly negatively correlated with blood urea nitrogen. Based on our results, we conclude that in patients with severe AHF, individual and total serum FFAs are slightly associated with established laboratory and clinical parameters, which are indicators of heart failure severity.
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Affiliation(s)
- Iva Klobučar
- Department of Cardiology, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia; (I.K.); (M.T.)
| | - Helga Hinteregger
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (H.H.); (M.L.); (W.S.)
| | - Margarete Lechleitner
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (H.H.); (M.L.); (W.S.)
| | - Matias Trbušić
- Department of Cardiology, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia; (I.K.); (M.T.)
- School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Gudrun Pregartner
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, 8036 Graz, Austria; (G.P.); (A.B.)
| | - Andrea Berghold
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, 8036 Graz, Austria; (G.P.); (A.B.)
| | - Wolfgang Sattler
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (H.H.); (M.L.); (W.S.)
- BioTechMed-Graz, 8010 Graz, Austria
| | - Saša Frank
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (H.H.); (M.L.); (W.S.)
- BioTechMed-Graz, 8010 Graz, Austria
| | - Vesna Degoricija
- School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Department of Medicine, Sisters of Charity University Hospital Centre, 10000 Zagreb, Croatia
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8
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Kang Q, Zhu X, Ren D, Ky A, MacDougald OA, O'Rourke RW, Rui L. Adipose METTL14-Elicited N 6 -Methyladenosine Promotes Obesity, Insulin Resistance, and NAFLD Through Suppressing β Adrenergic Signaling and Lipolysis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301645. [PMID: 37526326 PMCID: PMC10558699 DOI: 10.1002/advs.202301645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/08/2023] [Indexed: 08/02/2023]
Abstract
White adipose tissue (WAT) lipolysis releases free fatty acids as a key energy substance to support metabolism in fasting, cold exposure, and exercise. Atgl, in concert with Cgi-58, catalyzes the first lipolytic reaction. The sympathetic nervous system (SNS) stimulates lipolysis via neurotransmitter norepinephrine that activates adipocyte β adrenergic receptors (Adrb1-3). In obesity, adipose Adrb signaling and lipolysis are impaired, contributing to pathogenic WAT expansion; however, the underling mechanism remains poorly understood. Recent studies highlight importance of N6 -methyladenosine (m6A)-based RNA modification in health and disease. METTL14 heterodimerizes with METTL3 to form an RNA methyltransferase complex that installs m6A in transcripts. Here, this work shows that adipose Mettl3 and Mettl14 are influenced by fasting, refeeding, and insulin, and are upregulated in high fat diet (HFD) induced obesity. Adipose Adrb2, Adrb3, Atgl, and Cgi-58 transcript m6A contents are elevated in obesity. Mettl14 ablation decreases these transcripts' m6A contents and increases their translations and protein levels in adipocytes, thereby increasing Adrb signaling and lipolysis. Mice with adipocyte-specific deletion of Mettl14 are resistant to HFD-induced obesity, insulin resistance, glucose intolerance, and nonalcoholic fatty liver disease (NAFLD). These results unravel a METTL14/m6A/translation pathway governing Adrb signaling and lipolysis. METTL14/m6A-based epitranscriptomic reprogramming impairs adipose Adrb signaling and lipolysis, promoting obesity, NAFLD, and metabolic disease.
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Affiliation(s)
- Qianqian Kang
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Elizabeth Weiser Caswell Diabetes InstituteUniversity of MichiganAnn ArborMI48109USA
| | - Xiaorong Zhu
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Department of EndocrinologyBeijing Tongren HospitalCapital Medical UniversityBeijing Diabetes InstituteBeijing100730China
| | - Decheng Ren
- Department of MedicineUniversity of ChicagoChicagoIL60637USA
| | - Alexander Ky
- Department of SurgeryUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Ormond A. MacDougald
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Elizabeth Weiser Caswell Diabetes InstituteUniversity of MichiganAnn ArborMI48109USA
- Department of Internal MedicineUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Robert W. O'Rourke
- Department of SurgeryUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Department of SurgeryVeterans Affairs Ann Arbor Healthcare SystemAn ArborMI48105USA
| | - Liangyou Rui
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Elizabeth Weiser Caswell Diabetes InstituteUniversity of MichiganAnn ArborMI48109USA
- Department of Internal MedicineUniversity of Michigan Medical SchoolAnn ArborMI48109USA
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9
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Imi Y, Amano R, Kasahara N, Obana Y, Hosooka T. Nicotinamide mononucleotide induces lipolysis by regulating ATGL expression via the SIRT1-AMPK axis in adipocytes. Biochem Biophys Rep 2023; 34:101476. [PMID: 37144119 PMCID: PMC10151261 DOI: 10.1016/j.bbrep.2023.101476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/06/2023] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) -dependent protein deacetylase SIRT1 plays an important role in the regulation of metabolism. Although the administration of nicotinamide mononucleotide (NMN), a key NAD+ intermediate, has been shown to ameliorate metabolic disorders, such as insulin resistance and glucose intolerance, the direct effect of NMN on the regulation of lipid metabolism in adipocytes remains unclear. We here investigated the effect of NMN on lipid storage in 3T3-L1 differentiated adipocytes. Oil-red O staining showed that NMN treatment reduced lipid accumulation in these cells. NMN was found to enhance lipolysis in adipocytes since the concentration of glycerol in the media was increased by NMN treatment. Western blotting and real-time RT-PCR analysis revealed that adipose triglyceride lipase (ATGL) expression at both protein and mRNA level was increased with NMN treatment in 3T3-L1 adipocytes. Whereas NMN increased SIRT1 expression and AMPK activation, an AMPK inhibitor compound C restored the NMN-dependent upregulation of ATGL expression in these cells, suggesting that NMN upregulates ATGL expression through the SIRT1-AMPK axis. NMN administration significantly decreased subcutaneous fat mass in mice on a high-fat diet. We also found that adipocyte size in subcutaneous fat was decreased with NMN treatment. Consistent with the alteration of fat mass and adipocyte size, the ATGL expression in subcutaneous fat was slightly, albeit significantly, increased with NMN treatment. These results indicate that NMN suppresses subcutaneous fat mass in diet-induced obese mice, potentially in part via the upregulation of ATGL. Unexpectedly, the reduction in fat mass as well as ATGL upregulation with NMN treatment were not observed in epididymal fat, implying that the effects of NMN are site-specific in adipose tissue. Thus, these findings provide important insights into the mechanism of NMN/NAD+ in the regulation of metabolism.
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10
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Prentice KJ, Lee A, Cedillo P, Inouye KE, Ertunc ME, Riveros JK, Lee GY, Hotamisligil GS. Sympathetic tone dictates the impact of lipolysis on FABP4 secretion. J Lipid Res 2023; 64:100386. [PMID: 37172691 PMCID: PMC10248869 DOI: 10.1016/j.jlr.2023.100386] [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: 10/20/2022] [Revised: 04/19/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Levels of circulating fatty acid binding protein 4 (FABP4) protein are strongly associated with obesity and metabolic disease in both mice and humans, and secretion is stimulated by β-adrenergic stimulation both in vivo and in vitro. Previously, lipolysis-induced FABP4 secretion was found to be significantly reduced upon pharmacological inhibition of adipose triglyceride lipase (ATGL) and was absent from adipose tissue explants from mice specifically lacking ATGL in their adipocytes (ATGLAdpKO). Here, we find that upon activation of β-adrenergic receptors in vivo, ATGLAdpKO mice unexpectedly exhibited significantly higher levels of circulating FABP4 as compared with ATGLfl/fl controls, despite no corresponding induction of lipolysis. We generated an additional model with adipocyte-specific deletion of both FABP4 and ATGL (ATGL/FABP4AdpKO) to evaluate the cellular source of this circulating FABP4. In these animals, there was no evidence of lipolysis-induced FABP4 secretion, indicating that the source of elevated FABP4 levels in ATGLAdpKO mice was indeed from the adipocytes. ATGLAdpKO mice exhibited significantly elevated corticosterone levels, which positively correlated with plasma FABP4 levels. Pharmacological inhibition of sympathetic signaling during lipolysis using hexamethonium or housing mice at thermoneutrality to chronically reduce sympathetic tone significantly reduced FABP4 secretion in ATGLAdpKO mice compared with controls. Therefore, activity of a key enzymatic step of lipolysis mediated by ATGL, per se, is not required for in vivo stimulation of FABP4 secretion from adipocytes, which can be induced through sympathetic signaling.
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Affiliation(s)
- Kacey J Prentice
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Alexandra Lee
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Paulina Cedillo
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Karen E Inouye
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Meric Erikci Ertunc
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Jillian K Riveros
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Grace Yankun Lee
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Gökhan S Hotamisligil
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA.
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11
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Kersten S. The impact of fasting on adipose tissue metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159262. [PMID: 36521736 DOI: 10.1016/j.bbalip.2022.159262] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/20/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
Fasting and starvation were common occurrences during human evolution and accordingly have been an important environmental factor shaping human energy metabolism. Humans can tolerate fasting reasonably well through adaptative and well-orchestrated time-dependent changes in energy metabolism. Key features of the adaptive response to fasting are the breakdown of liver glycogen and muscle protein to produce glucose for the brain, as well as the gradual depletion of the fat stores, resulting in the release of glycerol and fatty acids into the bloodstream and the production of ketone bodies in the liver. In this paper, an overview is presented of our current understanding of the effects of fasting on adipose tissue metabolism. Fasting leads to reduced uptake of circulating triacylglycerols by adipocytes through inhibition of the activity of the rate-limiting enzyme lipoprotein lipase. In addition, fasting stimulates the degradation of stored triacylglycerols by activating the key enzyme adipose triglyceride lipase. The mechanisms underlying these events are discussed, with a special interest in insights gained from studies on humans. Furthermore, an overview is presented of the effects of fasting on other metabolic pathways in the adipose tissue, including fatty acid synthesis, glucose uptake, glyceroneogenesis, autophagy, and the endocrine function of adipose tissue.
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Affiliation(s)
- Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, the Netherlands.
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12
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Xu J, Liu Z, Zhang J, Chen S, Wang W, Zhao X, Zhen M, Huang X. N-end Rule-Mediated Proteasomal Degradation of ATGL Promotes Lipid Storage. Diabetes 2023; 72:210-222. [PMID: 36346641 PMCID: PMC9871197 DOI: 10.2337/db22-0362] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022]
Abstract
Cellular lipid storage is regulated by the balance of lipogenesis and lipolysis. The rate-limiting triglyceride hydrolase ATGL (desnutrin/PNPLA2) is critical for lipolysis. The control of ATGL transcription, localization, and activation has been intensively studied, while regulation of the protein stability of ATGL is much less explored. In this study, we showed that the protein stability of ATGL is regulated by the N-end rule in cultured cells and in mice. The N-end rule E3 ligases UBR1 and UBR2 reduce the level of ATGL and affect lipid storage. The N-end rule-resistant ATGL(F2A) mutant, in which the N-terminal phenylalanine (F) of ATGL is substituted by alanine (A), has increased protein stability and enhanced lipolysis activity. ATGLF2A/F2A knock-in mice are protected against high-fat diet (HFD)-induced obesity, hepatic steatosis, and insulin resistance. Hepatic knockdown of Ubr1 attenuates HFD-induced hepatic steatosis by enhancing the ATGL level. Finally, the protein levels of UBR1 and ATGL are negatively correlated in the adipose tissue of obese mice. Our study reveals N-end rule-mediated proteasomal regulation of ATGL, a finding that may potentially be beneficial for treatment of obesity.
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Affiliation(s)
- Jiesi Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Corresponding authors: Jiesi Xu, , and Xun Huang,
| | - Zhenglong Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jianxin Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Siyu Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wei Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xuefan Zhao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mei Zhen
- Lunenfeld–Tanebaum Research Institute, Departments of Molecular Genetics and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Corresponding authors: Jiesi Xu, , and Xun Huang,
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13
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Khazaal AQ, Haque N, Krager CR, Krager SL, Chambers C, Wilber A, Tischkau SA. Aryl hydrocarbon receptor affects circadian-regulated lipolysis through an E-Box-dependent mechanism. Mol Cell Endocrinol 2023; 559:111809. [PMID: 36283500 PMCID: PMC10509633 DOI: 10.1016/j.mce.2022.111809] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022]
Abstract
An internal circadian clock regulates timing of systemic energy homeostasis. The central clock in the hypothalamic suprachiasmatic nucleus (SCN) directs local clocks in peripheral tissues such as liver, muscle, and adipose tissue to synchronize metabolism with food intake and rest/activity cycles. Aryl hydrocarbon receptor (AhR) interacts with the molecular circadian clockworks. Activation of AhR dampens rhythmic expression of core clock genes, which may lead to metabolic dysfunction. Given the importance of appropriately-timed adipose tissue function to regulation of energy homeostasis, this study focused on mechanisms by which AhR may influence clock-controlled adipose tissue activity. We hypothesized that AhR activation in adipose tissue would impair lipolysis by dampening adipose rhythms, leading to a decreased lipolysis rate during fasting, and subsequently, altered serum glucose concentrations. Levels of clock gene and lipolysis gene transcripts in mouse mesenchymal stem cells (BMSCs) differentiated into mature adipocytes were suppressed by the AhR agonist β-napthoflavone (BNF), in an AhR dependent manner. BNF altered rhythms of core clock gene and lipolysis gene transcripts in C57bl6/J mice. BNF reduced serum free fatty acids, glycerol and liver glycogen. Chromatin immunoprecipitation indicated that BNF increased binding of AhR to E-Box elements in clock gene and lipolysis gene promoters. These data establish a link between AhR activation and impaired lipolysis, specifically by altering adipose tissue rhythmicity. In response to the decreased available energy from impaired lipolysis, the body increases glycogenolysis, thereby degrading more glycogen to provide necessary energy.
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Affiliation(s)
- Ali Qasim Khazaal
- Biotechnology Department, College of Science, University of Baghdad, Baghdad, Iraq; Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Nazmul Haque
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Callie R Krager
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Stacey L Krager
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Christopher Chambers
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Andrew Wilber
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Shelley A Tischkau
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA; Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA.
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14
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Yamamuro T, Nakamura S, Yanagawa K, Tokumura A, Kawabata T, Fukuhara A, Teranishi H, Hamasaki M, Shimomura I, Yoshimori T. Loss of RUBCN/rubicon in adipocytes mediates the upregulation of autophagy to promote the fasting response. Autophagy 2022; 18:2686-2696. [PMID: 35282767 PMCID: PMC9629072 DOI: 10.1080/15548627.2022.2047341] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Upon fasting, adipocytes release their lipids that accumulate in the liver, thus promoting hepatic steatosis and ketone body production. However, the mechanisms underlying this process are not fully understood. In this study, we found that fasting caused a substantial decrease in the adipose levels of RUBCN/rubicon, a negative regulator of macroautophagy/autophagy, along with an increase in autophagy. Adipose-specific rubcn-knockout mice exhibited systemic fat loss that was not accelerated by fasting. Genetic inhibition of autophagy in adipocytes in fasted mice led to a reduction in fat loss, hepatic steatosis, and ketonemia. In terms of mechanism, autophagy decreased the levels of its substrates NCOA1/SRC-1 and NCOA2/TIF2, which are also coactivators of PPARG/PPARγ, leading to a fasting-induced reduction in the mRNA levels of adipogenic genes in adipocytes. Furthermore, RUBCN in adipocytes was degraded through the autophagy pathway, suggesting that autophagic degradation of RUBCN serves as a feedforward system for autophagy induction during fasting. Collectively, we propose that loss of adipose RUBCN promotes a metabolic response to fasting via increasing autophagic activity.
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Affiliation(s)
- Tadashi Yamamuro
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Shuhei Nakamura
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan.,Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Institute for Advanced Co-Creation Studies, Osaka University, Suita, Japan
| | - Kyosuke Yanagawa
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Ayaka Tokumura
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tsuyoshi Kawabata
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan.,Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Atsunori Fukuhara
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Adipose Management, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Hirofumi Teranishi
- Pharmaceutical Frontier Research Laboratories, Central Pharmaceutical Research Institute, JT Inc., Yokohama, Japan
| | - Maho Hamasaki
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan.,Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Suita, Japan.,Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
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15
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Yang H, Wang Y, Tang MC, Waters P, Wang S, Allard P, Ryan RO, Nuyt AM, Paradis P, Schiffrin EL, Furtos A, Mitchell GA. Cardiac-specific deficiency of 3-hydroxy-3-methylglutaryl coenzyme A lyase in mice causes cardiomyopathy and a distinct pattern of acyl-coenzyme A-related biomarkers. Mol Genet Metab 2022; 137:257-264. [PMID: 36228350 DOI: 10.1016/j.ymgme.2022.09.008] [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: 07/12/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 10/31/2022]
Abstract
Deficiency of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase (HL) is an autosomal recessive inborn error of acyl-CoA metabolism affecting the last step of leucine degradation. Patients with HL deficiency (HLD) can develop a potentially fatal cardiomyopathy. We created mice with cardiomyocyte-specific HLD (HLHKO mice), inducing Cre recombinase-mediated deletion of exon 2 at two months of age. HLHKO mice survive, but develop left ventricular hypertrophy by 9 months. Also, within minutes after intraperitoneal injection of the leucine metabolite 2-ketoisocaproate (KIC), they show transient left ventricular hypocontractility and dilation. Leucine-related acyl-CoAs were elevated in HLHKO heart (e.g., HMG-CoA, 34.0 ± 4.4 nmol/g versus 0.211 ± 0.041 in controls, p < 0.001; 3-methylcrotonyl-CoA, 5.84 ± 0.69 nmol/g versus 0.282 ± 0.043, p < 0.001; isovaleryl-CoA, 1.86 ± 0.30 nmol/g versus 0.024 ± 0.014, p < 0.01), a similar pattern to that in liver of mice with hepatic HL deficiency. After KIC loading, HMG-CoA levels in HLHKO heart were higher than under basal conditions, as were the ratios of HMG-CoA/acetyl-CoA and of HMG-CoA/succinyl-CoA. In contrast to the high levels of multiple leucine-related acyl-CoAs, biomarkers in urine and plasma of HLHKO mice show isolated hyper-3-methylglutaconic aciduria (700.8 ± 48.4 mmol/mol creatinine versus 37.6 ± 2.4 in controls, p < 0.001), and elevated C5-hydroxyacylcarnitine in plasma (0.248 ± 0.014 μmol/L versus 0.048 ± 0.005 in controls, p < 0.001). Mice with liver-specific HLD were compared, and showed normal echocardiographic findings and normal acyl-CoA profiles in heart. This study of nonhepatic tissue-specific HLD outside of liver reveals organ-specific origins of diagnostic biomarkers for HLD in blood and urine and shows that mouse cardiac HL is essential for myocardial function in a cell-autonomous, organ-autonomous fashion.
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Affiliation(s)
- Hao Yang
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Québec, Canada
| | - Youlin Wang
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Québec, Canada
| | | | - Paula Waters
- Medical Genetics Service, Department of Laboratory Medicine, CHU Sherbrooke and Department of Pediatrics, Université de Sherbrooke, Québec, Canada
| | - Shupei Wang
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Québec, Canada
| | - Pierre Allard
- Biochemical Genetics Laboratory, CHU Sainte-Justine, Montreal, Québec, Canada
| | - Robert O Ryan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Anne-Monique Nuyt
- Sainte-Justine University Hospital and Research Center, University of Montreal, Montreal, Québec, Canada
| | - Pierre Paradis
- Hypertension and Vascular Research Unit, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Québec, Canada
| | - Ernesto L Schiffrin
- Hypertension and Vascular Research Unit, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Québec, Canada
| | - Alexandra Furtos
- Département de Chimie, Université de Montréal, Montreal, Québec, Canada
| | - Grant A Mitchell
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Québec, Canada.
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16
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Essential Amino Acids-Rich Diet Decreased Adipose Tissue Storage in Adult Mice: A Preliminary Histopathological Study. Nutrients 2022; 14:nu14142915. [PMID: 35889872 PMCID: PMC9316883 DOI: 10.3390/nu14142915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Excess body adipose tissue accumulation is a common and growing health problem caused by an unbalanced diet and/or junk food. Although the effects of dietary fat and glucose on lipid metabolism regulation are well known, those of essential amino acids (EAAs) have been poorly investigated. Our aim was to study the influence of a special diet containing all EAAs on retroperitoneal white adipose tissue (rpWAT) and interscapular brown adipose tissue (BAT) of mice. Methods: Two groups of male Balb/C mice were used. The first was fed with a standard diet. The second was fed with an EAAs-rich diet (EAARD). After 3 weeks, rpWAT and BAT were removed and prepared for subsequent immunohistochemical analysis. Results: EAARD, although consumed significantly less, moderately reduced body weight and BAT, but caused a massive reduction in rpWAT. Conversely, the triceps muscle increased in mass. In rpWAT, the size of adipocytes was very small, with increases in leptin, adiponectin and IL-6 immunostaining. In BAT, there was a reduction in lipid droplet size and a simultaneous increase in UCP-1 and SIRT-3. Conclusions: A diet containing a balanced mixture of free EAA may modulate body adiposity in mice, promoting increased thermogenesis.
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17
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NAFLD: Mechanisms, Treatments, and Biomarkers. Biomolecules 2022; 12:biom12060824. [PMID: 35740949 PMCID: PMC9221336 DOI: 10.3390/biom12060824] [Citation(s) in RCA: 97] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 05/31/2022] [Accepted: 06/02/2022] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic-associated fatty liver disease (MAFLD), is one of the most common causes of liver diseases worldwide. NAFLD is growing in parallel with the obesity epidemic. No pharmacological treatment is available to treat NAFLD, specifically. The reason might be that NAFLD is a multi-factorial disease with an incomplete understanding of the mechanisms involved, an absence of accurate and inexpensive imaging tools, and lack of adequate non-invasive biomarkers. NAFLD consists of the accumulation of excess lipids in the liver, causing lipotoxicity that might progress to metabolic-associated steatohepatitis (NASH), liver fibrosis, and hepatocellular carcinoma. The mechanisms for the pathogenesis of NAFLD, current interventions in the management of the disease, and the role of sirtuins as potential targets for treatment are discussed here. In addition, the current diagnostic tools, and the role of non-coding RNAs as emerging diagnostic biomarkers are summarized. The availability of non-invasive biomarkers, and accurate and inexpensive non-invasive diagnosis tools are crucial in the detection of the early signs in the progression of NAFLD. This will expedite clinical trials and the validation of the emerging therapeutic treatments.
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18
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Abdollahi A, Dowden BN, Buhman KK, Zembroski AS, Henderson GC. Albumin knockout mice exhibit reduced plasma free fatty acid concentration and enhanced insulin sensitivity. Physiol Rep 2022; 10:e15161. [PMID: 35238481 PMCID: PMC8892599 DOI: 10.14814/phy2.15161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/11/2021] [Accepted: 12/14/2021] [Indexed: 04/15/2023] Open
Abstract
Circulating albumin is expected to play a significant role in the trafficking of plasma free fatty acids (FFA) between tissues, such as FFA transfer from adipose tissue to the liver. However, it was not yet known how disrupting FFA binding to albumin in circulation would alter lipid metabolism and any resulting impacts upon control of glycemia. To improve understanding of metabolic control, we aimed to determine whether lack of serum albumin would decrease plasma FFA, hepatic lipid storage, whole body substrate oxidation, and glucose metabolism. Male and female homozygous albumin knockout mice and C57BL/6J wild type controls, each on a standard diet containing a moderate fat content, were studied at 6-8 weeks of age. Indirect calorimetry, glucose tolerance testing, insulin tolerance testing, exercise performance, plasma proteome, and tissue analyses were performed. In both sexes of albumin knockout mice compared to the wild type mice, significant reductions (p < 0.05) were observed for plasma FFA concentration, hepatic triacylglycerol and diacylglycerol content, blood glucose during the glucose tolerance test, and blood glucose during the insulin tolerance test. Albumin deficiency did not reduce whole body fat oxidation over a 24-h period and did not alter exercise performance in an incremental treadmill test. The system-level phenotypic changes in lipid and glucose metabolism were accompanied by reduced hepatic perilipin-2 expression (p < 0.05), as well as increased expression of adiponectin (p < 0.05) and glucose transporter-4 (p < 0.05) in adipose tissue. The results indicate an important role of albumin and plasma FFA concentration in lipid metabolism and glucoregulation.
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Affiliation(s)
- Afsoun Abdollahi
- Department of Nutrition SciencePurdue UniversityWest LafayetteIndianaUSA
| | - Brianna N. Dowden
- Department of Nutrition SciencePurdue UniversityWest LafayetteIndianaUSA
| | - Kimberly K. Buhman
- Department of Nutrition SciencePurdue UniversityWest LafayetteIndianaUSA
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19
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Romero AR, Mu A, Ayres JS. Adipose triglyceride lipase mediates lipolysis and lipid mobilization in response to iron-mediated negative energy balance. iScience 2022; 25:103941. [PMID: 35265813 PMCID: PMC8899412 DOI: 10.1016/j.isci.2022.103941] [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: 09/13/2021] [Revised: 12/23/2021] [Accepted: 02/14/2022] [Indexed: 11/09/2022] Open
Abstract
Maintenance of energy balance is essential for overall organismal health. Mammals have evolved complex regulatory mechanisms that control energy intake and expenditure. Traditionally, studies have focused on understanding the role of macronutrient physiology in energy balance. In the present study, we examined the role of the essential micronutrient iron in regulating energy balance. We found that a short course of dietary iron caused a negative energy balance resulting in a severe whole body wasting phenotype. This disruption in energy balance was because of impaired intestinal nutrient absorption. In response to dietary iron-induced negative energy balance, adipose triglyceride lipase (ATGL) was necessary for wasting of subcutaneous white adipose tissue and lipid mobilization. Fat-specific ATGL deficiency protected mice from fat wasting, but caused a severe cachectic response in mice when fed iron. Our work reveals a mechanism for micronutrient control of lipolysis that is necessary for regulating mammalian energy balance.
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Affiliation(s)
- Alicia R. Romero
- Molecular and Systems Physiology Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Gene Expression Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Nomis Center for Immunobiology and Microbial Pathogenesis, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Division of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Andre Mu
- Molecular and Systems Physiology Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Gene Expression Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Nomis Center for Immunobiology and Microbial Pathogenesis, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Janelle S. Ayres
- Molecular and Systems Physiology Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Gene Expression Lab, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Nomis Center for Immunobiology and Microbial Pathogenesis, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA,Corresponding author
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20
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Lu JF, Zhu MQ, Xie BC, Shi XC, Liu H, Zhang RX, Xia B, Wu JW. Camptothecin effectively treats obesity in mice through GDF15 induction. PLoS Biol 2022; 20:e3001517. [PMID: 35202387 PMCID: PMC8870521 DOI: 10.1371/journal.pbio.3001517] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 12/17/2021] [Indexed: 12/21/2022] Open
Abstract
Elevated circulating levels of growth differentiation factor 15 (GDF15) have been shown to reduce food intake and lower body weight through activation of hindbrain receptor glial-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) in rodents and nonhuman primates, thus endogenous induction of this peptide holds promise for obesity treatment. Here, through in silico drug-screening methods, we found that small molecule Camptothecin (CPT), a previously identified drug with potential antitumor activity, is a GDF15 inducer. Oral CPT administration increases circulating GDF15 levels in diet-induced obese (DIO) mice and genetic ob/ob mice, with elevated Gdf15 expression predominantly in the liver through activation of integrated stress response. In line with GDF15's anorectic effect, CPT suppresses food intake, thereby reducing body weight, blood glucose, and hepatic fat content in obese mice. Conversely, CPT loses these beneficial effects when Gdf15 is inhibited by a neutralizing antibody or AAV8-mediated liver-specific knockdown. Similarly, CPT failed to reduce food intake and body weight in GDF15's specific receptor GFRAL-deficient mice despite high levels of GDF15. Together, these results indicate that CPT is a promising anti-obesity agent through activation of GDF15-GFRAL pathway.
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Affiliation(s)
- Jun Feng Lu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Meng Qing Zhu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Bao Cai Xie
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiao Chen Shi
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Huan Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Rui Xin Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Bo Xia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
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21
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Zhao C, Wang Y, Yang H, Wang S, Tang MC, Cyr D, Parente F, Allard P, Waters P, Furtos A, Yang G, Mitchell GA. Propionic acidemia in mice: Liver acyl-CoA levels and clinical course. Mol Genet Metab 2022; 135:47-55. [PMID: 34896004 DOI: 10.1016/j.ymgme.2021.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/20/2021] [Accepted: 11/21/2021] [Indexed: 12/11/2022]
Abstract
Propionic acidemia (PA) is a severe autosomal recessive metabolic disease caused by deficiency of propionyl-CoA carboxylase (PCC). We studied PA transgenic (Pat) mice that lack endogenous PCC but express a hypoactive human PCCA cDNA, permitting their survival. Pat cohorts followed from 3 to 20 weeks of age showed growth failure and lethal crises of lethargy and hyperammonemia, commoner in males (27/50, 54%) than in females (11/52, 21%) and occurring mainly in Pat mice with the most severe growth deficiency. Groups of Pat mice were studied under basal conditions (P-Ba mice) and during acute crises (P-Ac). Plasma acylcarnitines in P-Ba mice, compared to controls, showed markedly elevated C3- and low C2-carnitine, with a further decrease in C2-carnitine in P-Ac mice. These clinical and biochemical findings resemble those of human PA patients. Liver acyl-CoA measurements showed that propionyl-CoA was a minor species in controls (propionyl-CoA/acetyl-CoA ratio, 0.09). In contrast, in P-Ba liver the ratio was 1.4 and in P-Ac liver, 13, with concurrent reductions of the levels of acetyl-CoA and other acyl-CoAs. Plasma ammonia levels in control, P-Ba and P-Ac mice were 109 ± 10, 311 ± 48 and 551 ± 61 μmol/L respectively. Four-week administration to Pat mice, of carglumate (N-carbamyl-L-glutamic acid), an analogue of N-carbamylglutamate, the product of the only acyl-CoA-requiring reaction directly related to the urea cycle, was associated with increased food consumption, improved growth and absence of fatal crises. Pat mice showed many similarities to human PA patients and provide a useful model for studying tissue pathophysiology and treatment outcomes.
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Affiliation(s)
- Chen Zhao
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A & F University, Yangling, Shaanxi, China; Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Quebec, Canada
| | - Youlin Wang
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Quebec, Canada
| | - Hao Yang
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Quebec, Canada
| | - Shupei Wang
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Quebec, Canada
| | | | - Denis Cyr
- Medical Genetics Service, Department of Laboratory Medicine, CHU Sherbrooke and Department of Pediatrics, Université de Sherbrooke, Quebec, Canada
| | - Fabienne Parente
- Biochemical Genetics Laboratory, CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Pierre Allard
- Biochemical Genetics Laboratory, CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Paula Waters
- Medical Genetics Service, Department of Laboratory Medicine, CHU Sherbrooke and Department of Pediatrics, Université de Sherbrooke, Quebec, Canada
| | - Alexandra Furtos
- Département de Chimie, Université de Montréal, Montreal, Quebec, Canada
| | - Gongshe Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A & F University, Yangling, Shaanxi, China.
| | - Grant A Mitchell
- Medical Genetics Service, Department of Pediatrics and Research Center, CHU Sainte-Justine and Université de Montréal, Montreal, Quebec, Canada.
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22
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Grabner GF, Xie H, Schweiger M, Zechner R. Lipolysis: cellular mechanisms for lipid mobilization from fat stores. Nat Metab 2021; 3:1445-1465. [PMID: 34799702 DOI: 10.1038/s42255-021-00493-6] [Citation(s) in RCA: 215] [Impact Index Per Article: 71.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022]
Abstract
The perception that intracellular lipolysis is a straightforward process that releases fatty acids from fat stores in adipose tissue to generate energy has experienced major revisions over the last two decades. The discovery of new lipolytic enzymes and coregulators, the demonstration that lipophagy and lysosomal lipolysis contribute to the degradation of cellular lipid stores and the characterization of numerous factors and signalling pathways that regulate lipid hydrolysis on transcriptional and post-transcriptional levels have revolutionized our understanding of lipolysis. In this review, we focus on the mechanisms that facilitate intracellular fatty-acid mobilization, drawing on canonical and noncanonical enzymatic pathways. We summarize how intracellular lipolysis affects lipid-mediated signalling, metabolic regulation and energy homeostasis in multiple organs. Finally, we examine how these processes affect pathogenesis and how lipolysis may be targeted to potentially prevent or treat various diseases.
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Affiliation(s)
- Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Hao Xie
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
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23
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Han SL, Qian YC, Limbu SM, Wang J, Chen LQ, Zhang ML, Du ZY. Lipolysis and lipophagy play individual and interactive roles in regulating triacylglycerol and cholesterol homeostasis and mitochondrial form in zebrafish. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158988. [PMID: 34111526 DOI: 10.1016/j.bbalip.2021.158988] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/29/2021] [Accepted: 06/03/2021] [Indexed: 12/26/2022]
Abstract
Neutral lipases-mediated lipolysis and acid lipases-moderated lipophagy are two main processes for degradation of lipid droplets (LDs). However, the individual and interactive roles of these metabolic pathways are not well known across vertebrates. This study explored the roles of lipolysis and lipophagy from the aspect of neutral and acid lipases in zebrafish. We established zebrafish strains deficient in either adipose triglyceride lipase (atgl-/-; AKO fish) or lysosomal acid lipase (lal-/-; LKO fish) respectively, and then inhibited lipolysis in the LKO fish and lipophagy in the AKO fish by feeding diets supplemented with the corresponding inhibitors Atglistatin and 3-Methyladenine, respectively. Both the AKO and LKO fish showed reduced growth, swimming activity, and oxygen consumption. The AKO fish did not show phenotypes in adipose tissue, but mainly accumulated triacylglycerol (TAG) in liver, also, they had large LDs in the hepatocytes, and did not stimulate lipophagy as a compensation response but maintained basal lipophagy. The LKO fish reduced total lipid accumulation in the body but had high cholesterol content in liver; also, they accumulated small LDs in the hepatocytes, and showed increased lipolysis, especially Atgl expression, as a compensatory mechanism. Simultaneous inhibition of lipolysis and lipophagy in zebrafish resulted in severe liver damage, with the potential to trigger mitophagy. Overall, our study illustrates that lipolysis and lipophagy perform individual and interactive roles in maintaining homeostasis of TAG and cholesterol metabolism. Furthermore, the interactive roles of lipolysis and lipophagy may be essential in regulating the functions and form of mitochondria.
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Affiliation(s)
- Si-Lan Han
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Yu-Cheng Qian
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | | | - Jing Wang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Li-Qiao Chen
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Mei-Ling Zhang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Zhen-Yu Du
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China.
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24
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Powell DR, Revelli JP, Doree DD, DaCosta CM, Desai U, Shadoan MK, Rodriguez L, Mullens M, Yang QM, Ding ZM, Kirkpatrick LL, Vogel P, Zambrowicz B, Sands AT, Platt KA, Hansen GM, Brommage R. High-Throughput Screening of Mouse Gene Knockouts Identifies Established and Novel High Body Fat Phenotypes. Diabetes Metab Syndr Obes 2021; 14:3753-3785. [PMID: 34483672 PMCID: PMC8409770 DOI: 10.2147/dmso.s322083] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/04/2021] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Obesity is a major public health problem. Understanding which genes contribute to obesity may better predict individual risk and allow development of new therapies. Because obesity of a mouse gene knockout (KO) line predicts an association of the orthologous human gene with obesity, we reviewed data from the Lexicon Genome5000TM high throughput phenotypic screen (HTS) of mouse gene KOs to identify KO lines with high body fat. MATERIALS AND METHODS KO lines were generated using homologous recombination or gene trapping technologies. HTS body composition analyses were performed on adult wild-type and homozygous KO littermate mice from 3758 druggable mouse genes having a human ortholog. Body composition was measured by either DXA or QMR on chow-fed cohorts from all 3758 KO lines and was measured by QMR on independent high fat diet-fed cohorts from 2488 of these KO lines. Where possible, comparisons were made to HTS data from the International Mouse Phenotyping Consortium (IMPC). RESULTS Body fat data are presented for 75 KO lines. Of 46 KO lines where independent external published and/or IMPC KO lines are reported as obese, 43 had increased body fat. For the remaining 29 novel high body fat KO lines, Ksr2 and G2e3 are supported by data from additional independent KO cohorts, 6 (Asnsd1, Srpk2, Dpp8, Cxxc4, Tenm3 and Kiss1) are supported by data from additional internal cohorts, and the remaining 21 including Tle4, Ak5, Ntm, Tusc3, Ankk1, Mfap3l, Prok2 and Prokr2 were studied with HTS cohorts only. CONCLUSION These data support the finding of high body fat in 43 independent external published and/or IMPC KO lines. A novel obese phenotype was identified in 29 additional KO lines, with 27 still lacking the external confirmation now provided for Ksr2 and G2e3 KO mice. Undoubtedly, many mammalian obesity genes remain to be identified and characterized.
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Affiliation(s)
- David R Powell
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Jean-Pierre Revelli
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Deon D Doree
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Christopher M DaCosta
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Urvi Desai
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Melanie K Shadoan
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Lawrence Rodriguez
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Michael Mullens
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Qi M Yang
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Zhi-Ming Ding
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Laura L Kirkpatrick
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Peter Vogel
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
| | - Brian Zambrowicz
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Arthur T Sands
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
- Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Kenneth A Platt
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Gwenn M Hansen
- Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA
| | - Robert Brommage
- Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA
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25
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Henderson GC. Plasma Free Fatty Acid Concentration as a Modifiable Risk Factor for Metabolic Disease. Nutrients 2021; 13:nu13082590. [PMID: 34444750 PMCID: PMC8402049 DOI: 10.3390/nu13082590] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/18/2021] [Accepted: 07/27/2021] [Indexed: 02/07/2023] Open
Abstract
Plasma free fatty acid (FFA) concentration is elevated in obesity, insulin resistance (IR), non-alcoholic fatty liver disease (NAFLD), type 2 diabetes (T2D), and related comorbidities such as cardiovascular disease (CVD). Furthermore, experimentally manipulating plasma FFA in the laboratory setting modulates metabolic markers of these disease processes. In this article, evidence is presented indicating that plasma FFA is a disease risk factor. Elevations of plasma FFA can promote ectopic lipid deposition, IR, as well as vascular and cardiac dysfunction. Typically, elevated plasma FFA results from accelerated adipose tissue lipolysis, caused by a high adipose tissue mass, adrenal hormones, or other physiological stressors. Reducing an individual’s postabsorptive and postprandial plasma FFA concentration is expected to improve health. Lifestyle change could provide a significant opportunity for plasma FFA reduction. Various factors can impact plasma FFA concentration, such as chronic restriction of dietary energy intake and weight loss, as well as exercise, sleep quality and quantity, and cigarette smoking. In this review, consideration is given to multiple factors which lead to plasma FFA elevation and subsequent disruption of metabolic health. From considering a variety of medical conditions and lifestyle factors, it becomes clear that plasma FFA concentration is a modifiable risk factor for metabolic disease.
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Affiliation(s)
- Gregory C Henderson
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
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26
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Thiele A, Luettges K, Ritter D, Beyhoff N, Smeir E, Grune J, Steinhoff JS, Schupp M, Klopfleisch R, Rothe M, Wilck N, Bartolomaeus H, Migglautsch AK, Breinbauer R, Kershaw EE, Grabner GF, Zechner R, Kintscher U, Foryst-Ludwig A. Pharmacological inhibition of adipose tissue adipose triglyceride lipase by Atglistatin prevents catecholamine-induced myocardial damage. Cardiovasc Res 2021; 118:2488-2505. [PMID: 34061169 PMCID: PMC9890462 DOI: 10.1093/cvr/cvab182] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Indexed: 02/05/2023] Open
Abstract
AIMS Heart failure (HF) is characterized by an overactivation of β-adrenergic signalling that directly contributes to impairment of myocardial function. Moreover, β-adrenergic overactivation induces adipose tissue lipolysis, which may further worsen the development of HF. Recently, we demonstrated that adipose tissue-specific deletion of adipose triglyceride lipase (ATGL) prevents pressure-mediated HF in mice. In this study, we investigated the cardioprotective effects of a new pharmacological inhibitor of ATGL, Atglistatin, predominantly targeting ATGL in adipose tissue, on catecholamine-induced cardiac damage. METHODS AND RESULTS Male 129/Sv mice received repeated injections of isoproterenol (ISO, 25 mg/kg BW) to induce cardiac damage. Five days prior to ISO application, oral Atglistatin (2 mmol/kg diet) or control treatment was started. Two and twelve days after the last ISO injection cardiac function was analysed by echocardiography. The myocardial deformation was evaluated using speckle-tracking-technique. Twelve days after the last ISO injection, echocardiographic analysis revealed a markedly impaired global longitudinal strain, which was significantly improved by the application of Atglistatin. No changes in ejection fraction were observed. Further studies included histological-, WB-, and RT-qPCR-based analysis of cardiac tissue, followed by cell culture experiments and mass spectrometry-based lipidome analysis. ISO application induced subendocardial fibrosis and a profound pro-apoptotic cardiac response, as demonstrated using an apoptosis-specific gene expression-array. Atglistatin treatment led to a dramatic reduction of these pro-fibrotic and pro-apoptotic processes. We then identified a specific set of fatty acids (FAs) liberated from adipocytes under ISO stimulation (palmitic acid, palmitoleic acid, and oleic acid), which induced pro-apoptotic effects in cardiomyocytes. Atglistatin significantly blocked this adipocytic FA secretion. CONCLUSION This study demonstrates cardioprotective effects of Atglistatin in a mouse model of catecholamine-induced cardiac damage/dysfunction, involving anti-apoptotic and anti-fibrotic actions. Notably, beneficial cardioprotective effects of Atglistatin are likely mediated by non-cardiac actions, supporting the concept that pharmacological targeting of adipose tissue may provide an effective way to treat cardiac dysfunction.
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Affiliation(s)
- Arne Thiele
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Hessische Str. 3-4, 10115 Berlin, Germany,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Katja Luettges
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Hessische Str. 3-4, 10115 Berlin, Germany,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Daniel Ritter
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Hessische Str. 3-4, 10115 Berlin, Germany,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Niklas Beyhoff
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Hessische Str. 3-4, 10115 Berlin, Germany,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Elia Smeir
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Hessische Str. 3-4, 10115 Berlin, Germany,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany
| | - Jana Grune
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany,Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Physiology, 10115 Berlin, Germany
| | - Julia S Steinhoff
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Michael Schupp
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Hessische Str. 3-4, 10115 Berlin, Germany
| | - Robert Klopfleisch
- Department of Veterinary Pathology, College of Veterinary Medicine, Freie Universität, 14163 Berlin, Germany
| | | | - Nicola Wilck
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany,Experimental and Clinical Research Center, A Joint Cooperation of Max-Delbrück Center for Molecular Medicine, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany,Division of Nephrology and Internal Intensive Care Medicine, Charité - Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Hendrik Bartolomaeus
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany,Experimental and Clinical Research Center, A Joint Cooperation of Max-Delbrück Center for Molecular Medicine, Charité - Universitätsmedizin Berlin, 13125 Berlin, Germany
| | - Anna K Migglautsch
- Institute of Organic Chemistry, Graz University of Technology, 8010 Graz, Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology, 8010 Graz, Austria
| | - Erin E Kershaw
- Division of Endocrinology and Metabolism, University of Pittsburgh, PA, USA
| | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | | | - Anna Foryst-Ludwig
- Corresponding author. Tel: +49 30 450 525 373; fax: +49 30 450 525 901, E-mail:
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27
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Jain S, Pydi SP, Jung YH, Scortichini M, Kesner EL, Karcz TP, Cook DN, Gavrilova O, Wess J, Jacobson KA. Adipocyte P2Y14 receptors play a key role in regulating whole-body glucose and lipid homeostasis. JCI Insight 2021; 6:146577. [PMID: 34027896 PMCID: PMC8262345 DOI: 10.1172/jci.insight.146577] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/09/2021] [Indexed: 12/18/2022] Open
Abstract
Obesity is the major driver of the worldwide epidemic in type 2 diabetes (T2D). In the obese state, chronically elevated plasma free fatty acid levels contribute to peripheral insulin resistance, which can ultimately lead to the development of T2D. For this reason, drugs that are able to regulate lipolytic processes in adipocytes are predicted to have considerable therapeutic potential. Gi-coupled P2Y14 receptor (P2Y14R; endogenous agonist, UDP-glucose) is abundantly expressed in both mouse and human adipocytes. Because activated Gi-type G proteins exert an antilipolytic effect, we explored the potential physiological relevance of adipocyte P2Y14Rs in regulating lipid and glucose homeostasis. Metabolic studies indicate that the lack of adipocyte P2Y14R enhanced lipolysis only in the fasting state, decreased body weight, and improved glucose tolerance and insulin sensitivity. Mechanistic studies suggested that adipocyte P2Y14R inhibits lipolysis by reducing lipolytic enzyme activity, including ATGL and HSL. In agreement with these findings, agonist treatment of control mice with a P2Y14R agonist decreased lipolysis, an effect that was sensitive to inhibition by a P2Y14R antagonist. In conclusion, we demonstrate that adipose P2Y14Rs were critical regulators of whole-body glucose and lipid homeostasis, suggesting that P2Y14R antagonists might be beneficial for the therapy of obesity and T2D.
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Affiliation(s)
| | - Sai P Pydi
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | | | | | | | - Tadeusz P Karcz
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Donald N Cook
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
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An SJ, Lee EJ, Jeong SH, Hong YP, Ahn S, Yang YJ. Perinatal exposure to di-(2-ethylhexyl) phthalate induces hepatic lipid accumulation mediated by diacylglycerol acyltransferase 1. Hum Exp Toxicol 2021; 40:1698-1709. [PMID: 33832334 DOI: 10.1177/09603271211003314] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer in consumer products and medical devices. It is also suspected to exacerbate the development of fatty liver. However, the mechanisms underlying excessive lipid synthesis and its deposition in the liver are yet to be identified. This study was aimed to evaluate the molecular mechanisms of hepatic lipid accumulation in adult male offspring after perinatal exposure to DEHP. METHOD Corn oil and DEHP (0.75 mg/kg/day) were administered once per day to dam from gestation day 6 to postnatal day (PND) 21 by oral gavage. After the weaning period, DEHP treated male pups were categorized into early life stage- and lifelong period group. Male rats both control and early life stage group administered corn oil, and lifelong period group administered DEHP from PND 22 to 70. Histological examination and triglyceride (TG) levels in the liver were analyzed. Expressions of transcription factors associated with lipid accumulation in the liver were analyzed. RESULTS Both early life stage- and lifelong period group, hepatic TG levels, and mRNA and protein expression of diacylglycerol acyltransferase 1 (DGAT1) were significantly higher than control (TG: all p < 0.05, mRNA & protein: p < 0.05 and p < 0.001, respectively). The average body weight from PND 35 to 63, and mRNA and protein expression of sterol regulatory element binding protein 1c in lifelong period group were significantly lower than control (all p < 0.05); however, alanine transaminase were significantly higher than control (p < 0.01). CONCLUSION Perinatal exposure to DEHP may induce the hepatic lipid accumulation through up-regulation of DGAT1 expression.
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Affiliation(s)
- S J An
- Department of Neurology, Catholic Kwandong University International St Mary's Hospital, Incheon, Republic of Korea.,These authors are equally contributed to this work
| | - E J Lee
- Institute for Catholic Integrative Medicine, Incheon St Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Republic of Korea.,These authors are equally contributed to this work
| | - S-H Jeong
- Division of Gastroenterology, Department of Internal Medicine, Catholic Kwandong University International St Mary's Hospital, Incheon, Republic of Korea
| | - Y-P Hong
- Department of Preventive Medicine, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - S Ahn
- Department of Pathology, Catholic Kwandong University International St Mary's Hospital, Incheon, Republic of Korea
| | - Y-J Yang
- Institute of Biomedical Science, Catholic Kwandong University International St Mary's Hospital, Incheon, Republic of Korea
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SR-BI deficiency disassociates obesity from hepatic steatosis and glucose intolerance development in high fat diet-fed mice. J Nutr Biochem 2021; 89:108564. [DOI: 10.1016/j.jnutbio.2020.108564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023]
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Han SL, Liu Y, Limbu SM, Chen LQ, Zhang ML, Du ZY. The reduction of lipid-sourced energy production caused by ATGL inhibition cannot be compensated by activation of HSL, autophagy, and utilization of other nutrients in fish. FISH PHYSIOLOGY AND BIOCHEMISTRY 2021; 47:173-188. [PMID: 33245450 DOI: 10.1007/s10695-020-00904-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/18/2020] [Indexed: 06/11/2023]
Abstract
The adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL)-mediated lipolysis play important roles in lipid catabolism. ATGL is considered the central rate-limiting enzyme in the mobilization of fatty acids in mammals. Currently, severe fat accumulation has been commonly detected in farmed fish globally. However, the ATGL-mediated lipolysis and the potential synergy among ATGL, HSL, and autophagy, which is another way for lipid breakdown, have not been intensively understood in fish. In the present study, we added Atglistatin as an ATGL-specific inhibitor into the zebrafish diet and fed to the fish for 5 weeks. The results showed that the Atglistatin-treated fish exhibited severe fat deposition, reduced oxygen consumption, and fatty acid β-oxidation, accompanied with increased oxidative stress and inflammation. Furthermore, the Atglistatin-treated fish elevated total and phosphorylation protein expressions of HSL. However, the free fatty acids and lipase activities in organs were still systemically reduced in the Atglistatin-treated fish, and the autophagy marker LC3 was also decreased in the liver. On the other hand, glycogenolysis was stimulated but blood glucose was higher in the Atglistatin-treated fish. The transcriptomic analysis also provided the hint that the protein turnover efficiency in Atglistatin-treated fish was likely to be accelerated, but the protein content in whole fish was not affected. Taken together, ATGL plays crucial roles in energy homeostasis such that its inhibition causes loss of lipid-sourced energy production, which cannot be compensated by activation of HSL, autophagy, and utilization of other nutrients.
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Affiliation(s)
- Si-Lan Han
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Yan Liu
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Samwel M Limbu
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
- Department of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
- ECNU-UDSM Joint Research Center for Aquaculture and Fish Biology (JRCAFB), Dar es Salaam, Tanzania
| | - Li-Qiao Chen
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Mei-Ling Zhang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China
| | - Zhen-Yu Du
- LANEH, School of Life Sciences, East China Normal University, Shanghai, China.
- ECNU-UDSM Joint Research Center for Aquaculture and Fish Biology (JRCAFB), Shanghai, China.
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Wei W, Li Y, Li Y, Li D. Adipose-specific knockout of ubiquitin-conjugating enzyme E2L6 (Ube2l6) reduces diet-induced obesity, insulin resistance, and hepatic steatosis. J Pharmacol Sci 2020; 145:327-334. [PMID: 33712284 DOI: 10.1016/j.jphs.2020.12.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/10/2020] [Accepted: 12/28/2020] [Indexed: 12/13/2022] Open
Abstract
Ubiquitin/ISG15-conjugating enzyme E2 L6 (UBE2L6/Ube2l6) catalyzes protein ISGylation and ubiquitylation, post-translational modifications which regulate protein stability. Ube2l6 plays a role in promoting in vitro adipogenesis; however, its mechanism(s) of action and in vivo effects remain unknown. Here, we discovered that UBE2L6 levels were upregulated, and UBE2L6 and adipose triglyceride lipase (ATGL/Atgl) levels were negatively correlated, in white adipose tissue (WAT) from obese humans and obese mice. Therefore, we employed adipose-specific Ube2l6 knockout (Ube2l6AKO) mice and age-matched Ube2l6flox/flox controls to assess adipocyte Ube2l6's role in high-fat diet (HFD)-induced obesity, insulin resistance, and hepatic steatosis. HFD-fed Ube2l6AKO mice displayed lower subcutaneous and visceral WAT mass levels relative to controls. HFD-fed Ube2l6AKO mice also showed WAT adipocyte hypoplasia and hypotrophy as well as enhanced whole-body metabolic activity relative to controls. Furthermore, glucose intolerance, insulin resistance, compensatory hyperinsulinemia, hypercholesterolemia, and hepatic steatosis were lower in HFD-fed Ube2l6AKO mice as compared to controls. Mechanistically, we found that Atgl protein expression and Atgl-mediated lipolysis were negatively regulated by Ube2l6's promotion of Atgl protein ubiquitylation. Collectively, adipocyte Ube2l6 functions as a negative regulator of Atgl protein stability and, consequently, promotes HFD-induced obesity, insulin resistance, and hepatic steatosis.
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Affiliation(s)
- Weiping Wei
- Department of Endocrinology, Hainan General Hospital, Haikou, China
| | - Yunqian Li
- Hainan Provincial Healthcare Center, Hainan General Hospital, Haikou, China
| | - Yongyong Li
- Chuangxu Institute of Life Science, Chongqing, China
| | - Daoyuan Li
- Department of Urological Surgery, Hainan General Hospital, Haikou, China.
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Reinisch I, Schreiber R, Prokesch A. Regulation of thermogenic adipocytes during fasting and cold. Mol Cell Endocrinol 2020; 512:110869. [PMID: 32439414 DOI: 10.1016/j.mce.2020.110869] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022]
Abstract
Cold exposure activates brown and brown-like adipocytes that dissipate large amounts of glucose and fatty acids via uncoupling protein 1 (UCP1) to drive non-shivering thermogenesis (NST). Evidence for the existence of these thermogenic adipocytes in adult humans gave rise to a renaissance in research on brown adipose tissue, establishing it as linchpin of energy homeostasis and metabolic health. Besides low ambient temperature, shortage or excess of food affect thermoregulation. Upon high caloric meals thermogenic adipocytes burn excess calories and maintain energy balance. In contrast, in conditions of nutrient deprivation, counter-regulatory mechanisms prevent thermogenic adipocytes from "wasting" energy substrates that need to be conserved. In this review, we discuss cell-autonomous mechanisms, metabolites, and hormones that modify NST in response to nutrient fluctuations. In particular, we focus on how thermogenic adipocytes balance thermogenesis with systemic energy homeostasis during fasting periods.
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Affiliation(s)
- Isabel Reinisch
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism & Aging, Medical University of Graz, 8010, Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, 8010, Graz, Austria
| | - Andreas Prokesch
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism & Aging, Medical University of Graz, 8010, Graz, Austria; BioTechMed-Graz, 8010, Graz, Austria.
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Chu XY, Yang SZ, Zhu MQ, Zhang DY, Shi XC, Xia B, Yuan Y, Liu M, Wu JW. Isorhapontigenin Improves Diabetes in Mice via Regulating the Activity and Stability of PPARγ in Adipocytes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:3976-3985. [PMID: 32178518 DOI: 10.1021/acs.jafc.0c00515] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Isorhapontigenin is a natural bioactive stilbene isolated from various plants and fruits. It has been reported to exhibit several physiological activities including anticancer and anti-inflammation activity in vitro and in experimental animal models. This study aimed to investigate whether isorhapontigenin exerts antidiabetic effects in vivo. To this end, diabetic db/db mice were treated with either 25 mg kg-1 of isorhapontigenin or vehicle intraperitoneally for a period of 5 weeks. The results show that isorhapontigenin treatment significantly reduced postprandial levels of glucose, insulin, as well as free fatty acid, three markers of diabetes. Further studies show that isorhapontigenin treatment markedly improves insulin sensitivity and glucose tolerance of db/db mice as shown by ITT and GTT. Together, these physiological results show that isorhapontigenin possesses antidiabetic properties in vivo. Mechanistically, the isorhapontigenin-mediated antidiabetic effect is caused by favorable changes in adipose tissue, including reductions in adipocyte diameter and improved adipose insulin sensitivity. Further studies with 3T3-L1 cells show that isorhapontigenin treatment promotes preadipocyte differentiation by upregulation of the activity of the master adipogenic regulator PPARγ and deceleration of its proteasomal degradation. Together, our results establish for the first time an important role of isorhapontigenin as a potential nutraceutical agent for diabetes treatment.
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Affiliation(s)
- Xin Yi Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Shi Zhen Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Meng Qing Zhu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Dan Yang Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiao Chen Shi
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Bo Xia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Ye Yuan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Min Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
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Chen Y, Cai GH, Xia B, Wang X, Zhang CC, Xie BC, Shi XC, Liu H, Lu JF, Zhang RX, Zhu MQ, Liu M, Yang SZ, Yang Zhang D, Chu XY, Khan R, Wang YL, Wu JW. Mitochondrial aconitase controls adipogenesis through mediation of cellular ATP production. FASEB J 2020; 34:6688-6702. [PMID: 32212192 DOI: 10.1096/fj.201903224rr] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 11/11/2022]
Abstract
Mitochondrial aconitase (Aco2) catalyzes the conversion of citrate to isocitrate in the TCA cycle, which produces NADH and FADH2, driving synthesis of ATP through OXPHOS. In this study, to explore the relationship between adipogenesis and mitochondrial energy metabolism, we hypothesize that Aco2 may play a key role in the lipid synthesis. Here, we show that overexpression of Aco2 in 3T3-L1 cells significantly increased lipogenesis and adipogenesis, accompanied by elevated mitochondrial biogenesis and ATP production. However, when ATP is depleted by rotenone, an inhibitor of the respiratory chain, the promotive role of Aco2 in adipogenesis is abolished. In contrast to Aco2 overexpression, deficiency of Aco2 markedly reduced lipogenesis and adipogenesis, along with the decreased mitochondrial biogenesis and ATP production. Supplementation of isocitrate efficiently rescued the inhibitory effect of Aco2 deficiency. Similarly, the restorative effect of isocitrate was abolished in the presence of rotenone. Together, these results show that Aco2 sustains normal adipogenesis through mediating ATP production, revealing a potential mechanistic link between TCA cycle enzyme and lipid synthesis. Our work suggest that regulation of adipose tissue mitochondria function may be a potential way for combating abnormal adipogenesis related diseases such as obesity and lipodystrophy.
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Affiliation(s)
- Yan Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Guo He Cai
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Bo Xia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xin Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Cong Cong Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Bao Cai Xie
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xiao Chen Shi
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Huan Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jun Feng Lu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Rui Xin Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Meng Qing Zhu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Min Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Shi Zhen Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Dan Yang Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xin Yi Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Rajwali Khan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Yong Liang Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
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Xia B, Shi XC, Xie BC, Zhu MQ, Chen Y, Chu XY, Cai GH, Liu M, Yang SZ, Mitchell GA, Pang WJ, Wu JW. Urolithin A exerts antiobesity effects through enhancing adipose tissue thermogenesis in mice. PLoS Biol 2020; 18:e3000688. [PMID: 32218572 PMCID: PMC7141696 DOI: 10.1371/journal.pbio.3000688] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 04/08/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023] Open
Abstract
Obesity leads to multiple health problems, including diabetes, fatty liver, and even cancer. Here, we report that urolithin A (UA), a gut-microflora-derived metabolite of pomegranate ellagitannins (ETs), prevents diet-induced obesity and metabolic dysfunctions in mice without causing adverse effects. UA treatment increases energy expenditure (EE) by enhancing thermogenesis in brown adipose tissue (BAT) and inducing browning of white adipose tissue (WAT). Mechanistically, UA-mediated increased thermogenesis is caused by an elevation of triiodothyronine (T3) levels in BAT and inguinal fat depots. This is also confirmed in UA-treated white and brown adipocytes. Consistent with this mechanism, UA loses its beneficial effects on activation of BAT, browning of white fat, body weight control, and glucose homeostasis when thyroid hormone (TH) production is blocked by its inhibitor, propylthiouracil (PTU). Conversely, administration of exogenous tetraiodothyronine (T4) to PTU-treated mice restores UA-induced activation of BAT and browning of white fat and its preventive role on high-fat diet (HFD)-induced weight gain. Together, these results suggest that UA is a potent antiobesity agent with potential for human clinical applications.
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Affiliation(s)
- Bo Xia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiao Chen Shi
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Bao Cai Xie
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Meng Qing Zhu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Yan Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Xin Yi Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Guo He Cai
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Min Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Shi Zhen Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Grant A. Mitchell
- Division of Medical Genetics, Department of Paediatrics, Université de Montréal and Centre Hospitalier Universitaire Sainte-Justine, Montréal, Québec, Canada
| | - Wei Jun Pang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
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Yu L, Li Y, Grisé A, Wang H. CGI-58: Versatile Regulator of Intracellular Lipid Droplet Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:197-222. [PMID: 32705602 PMCID: PMC8063591 DOI: 10.1007/978-981-15-6082-8_13] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Comparative gene identification-58 (CGI-58), also known as α/β-hydrolase domain-containing 5 (ABHD5), is a member of a large family of proteins containing an α/β-hydrolase-fold. CGI-58 is well-known as the co-activator of adipose triglyceride lipase (ATGL), which is a key enzyme initiating cytosolic lipid droplet lipolysis. Mutations in either the human CGI-58 or ATGL gene cause an autosomal recessive neutral lipid storage disease, characterized by the excessive accumulation of triglyceride (TAG)-rich lipid droplets in the cytoplasm of almost all cell types. CGI-58, however, has ATGL-independent functions. Distinct phenotypes associated with CGI-58 deficiency commonly include ichthyosis (scaly dry skin), nonalcoholic steatohepatitis, and hepatic fibrosis. Through regulated interactions with multiple protein families, CGI-58 controls many metabolic and signaling pathways, such as lipid and glucose metabolism, energy balance, insulin signaling, inflammatory responses, and thermogenesis. Recent studies have shown that CGI-58 regulates the pathogenesis of common metabolic diseases in a tissue-specific manner. Future studies are needed to molecularly define ATGL-independent functions of CGI-58, including the newly identified serine protease activity of CGI-58. Elucidation of these versatile functions of CGI-58 may uncover fundamental cellular processes governing lipid and energy homeostasis, which may help develop novel approaches that counter against obesity and its associated metabolic sequelae.
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Affiliation(s)
- Liqing Yu
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Yi Li
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alison Grisé
- College of Computer, Math, and Natural Sciences, College of Behavioral and Social Sciences, University of Maryland, College Park, MD, USA
| | - Huan Wang
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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Trites MJ, Clugston RD. The role of adipose triglyceride lipase in lipid and glucose homeostasis: lessons from transgenic mice. Lipids Health Dis 2019; 18:204. [PMID: 31757217 PMCID: PMC6874817 DOI: 10.1186/s12944-019-1151-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
The ability of mammals to store and draw on fat reserves has been a driving force throughout evolution in an environment with intermittent nutrient availability. The discovery of adipose triglyceride lipase (ATGL) as a triglyceride lipase provided a heightened understanding of the mechanisms governing mobilization of fat reserves from adipose tissue. ATGL catalyses the initial step in adipose triglyceride lipolysis, working in concert with other enzymes to mobilize triglyceride for energy production. In addition to the role of ATGL in adipose tissue triglyceride mobilization, ATGL plays crucial roles in regulating lipid homeostasis in other tissues. These roles have been characterized primarily using transgenic mice with tissue-specific ATGL ablation. For example, the global ATGL knockout induces a severe cardiac defect that results in premature mortality that is mimicked by inducible cardiomyocyte-specific ATGL knockout. Global- and adipose-specific ATGL ablation induces a whole-body shift from lipid metabolism to glucose metabolism to satisfy metabolic demand primarily facilitated by an increase in glucose uptake by skeletal muscle. Generation of liver-specific ATGL knockouts has implicated hepatic lipolysis as a critical component of normal liver function. Analysis of β-cell ATGL knockouts implicates the necessity of pancreatic ATGL in insulin secretion. The objective of this review is to discuss the contributions of ATGL to systemic lipid- and glucose-homeostasis discovered through the study of transgenic mice.
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Affiliation(s)
- Michael J Trites
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada.,Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Robin D Clugston
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada. .,Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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38
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Kolbe I, Leinweber B, Brandenburger M, Oster H. Circadian clock network desynchrony promotes weight gain and alters glucose homeostasis in mice. Mol Metab 2019; 30:140-151. [PMID: 31767165 PMCID: PMC6807374 DOI: 10.1016/j.molmet.2019.09.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 09/23/2019] [Accepted: 09/28/2019] [Indexed: 11/21/2022] Open
Abstract
Objective A network of endogenous circadian clocks adapts physiology and behavior to recurring changes in environmental demands across the 24-hour day cycle. Circadian disruption promotes weight gain and type 2 diabetes development. In this study, we aim to dissect the roles of different tissue clocks in the regulation of energy metabolism. Methods We used mice with genetically ablated clock function in the circadian pacemaker of the suprachiasmatic nucleus (SCN) under different light and feeding conditions to study peripheral clock resetting and the role of the peripheral clock network in the regulation of glucose handling and metabolic homeostasis. Results In SCN clock-deficient mice, behavioral and non-SCN tissue clock rhythms are sustained under rhythmic lighting conditions but deteriorate quickly in constant darkness. In parallel to the loss of behavioral and molecular rhythms, the animals develop adiposity and impaired glucose utilization in constant darkness. Restoring peripheral clock rhythmicity and synchrony by time-restricted feeding normalizes body weight and glucose metabolism. Conclusions These data reveal the importance of an overall synchronized circadian clockwork for the maintenance of metabolic homeostasis. In mice with a non-functional SCN clock (SCN-KO), metabolic rhythms are retained in light-dark, but not in constant darkness (DD) conditions. Normal body weight regulation and glucose utilization do not require a functional SCN clock. Restoring peripheral clock gene expression rhythms via time-restricted feeding restores metabolic homeostasis in SCN-KO mice in DD.
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Affiliation(s)
- Isa Kolbe
- Institute of Neurobiology, University of Lübeck, Lübeck, Germany
| | - Brinja Leinweber
- Institute of Neurobiology, University of Lübeck, Lübeck, Germany
| | - Matthias Brandenburger
- Fraunhofer Research Institution for Marine Biotechnology and Cell Technology, Lübeck, Germany
| | - Henrik Oster
- Institute of Neurobiology, University of Lübeck, Lübeck, Germany.
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Mäkelä AM, Hohtola E, Miinalainen IJ, Autio JA, Schmitz W, Niemi KJ, Hiltunen JK, Autio KJ. Mitochondrial 2,4-dienoyl-CoA reductase (Decr) deficiency and impairment of thermogenesis in mouse brown adipose tissue. Sci Rep 2019; 9:12038. [PMID: 31427678 PMCID: PMC6700156 DOI: 10.1038/s41598-019-48562-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 08/07/2019] [Indexed: 12/17/2022] Open
Abstract
A large number of studies have demonstrated significance of polyunsaturated fatty acids (PUFAs) for human health. However, many aspects on signals translating PUFA-sensing into body homeostasis have remained enigmatic. To shed light on PUFA physiology, we have generated a mouse line defective in mitochondrial dienoyl-CoA reductase (Decr), which is a key enzyme required for β-oxidation of PUFAs. Previously, we have shown that these mice, whose oxidation of saturated fatty acid is intact but break-down of unsaturated fatty acids is blunted, develop severe hypoglycemia during metabolic stresses and fatal hypothermia upon acute cold challenge. In the current work, indirect calorimetry and thermography suggested that cold intolerance of Decr−/− mice is due to failure in maintaining appropriate heat production at least partly due to failure of brown adipose tissue (BAT) thermogenesis. Magnetic resonance imaging, electron microscopy, mass spectrometry and biochemical analysis showed attenuation in activation of lipolysis despite of functional NE-signaling and inappropriate expression of genes contributing to thermogenesis in iBAT when the Decr−/− mice were exposed to cold. We hypothesize that the failure in turning on BAT thermogenesis occurs due to accumulation of unsaturated long-chain fatty acids or their metabolites in Decr−/− mice BAT suppressing down-stream propagation of NE-signaling.
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Affiliation(s)
- Anne M Mäkelä
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Esa Hohtola
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
| | | | - Joonas A Autio
- Center for Biosystems Dynamics Research, RIKEN, Kobe, Japan.,Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
| | | | - Kalle J Niemi
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
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Diverse repertoire of human adipocyte subtypes develops from transcriptionally distinct mesenchymal progenitor cells. Proc Natl Acad Sci U S A 2019; 116:17970-17979. [PMID: 31420514 PMCID: PMC6731669 DOI: 10.1073/pnas.1906512116] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Single-cell sequencing technologies have revealed an unexpectedly broad repertoire of cells required to mediate complex functions in multicellular organisms. Despite the multiple roles of adipose tissue in maintaining systemic metabolic homeostasis, adipocytes are thought to be largely homogenous with only 2 major subtypes recognized in humans so far. Here we report the existence and characteristics of 4 distinct human adipocyte subtypes, and of their respective mesenchymal progenitors. The phenotypes of these distinct adipocyte subtypes are differentially associated with key adipose tissue functions, including thermogenesis, lipid storage, and adipokine secretion. The transcriptomic signature of "brite/beige" thermogenic adipocytes reveals mechanisms for iron accumulation and protection from oxidative stress, necessary for mitochondrial biogenesis and respiration upon activation. Importantly, this signature is enriched in human supraclavicular adipose tissue, confirming that these cells comprise thermogenic depots in vivo, and explain previous findings of a rate-limiting role of iron in adipose tissue browning. The mesenchymal progenitors that give rise to beige/brite adipocytes express a unique set of cytokines and transcriptional regulators involved in immune cell modulation of adipose tissue browning. Unexpectedly, we also find adipocyte subtypes specialized for high-level expression of the adipokines adiponectin or leptin, associated with distinct transcription factors previously implicated in adipocyte differentiation. The finding of a broad adipocyte repertoire derived from a distinct set of mesenchymal progenitors, and of the transcriptional regulators that can control their development, provides a framework for understanding human adipose tissue function and role in metabolic disease.
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Zhang X, Zhang CC, Yang H, Soni KG, Wang SP, Mitchell GA, Wu JW. An Epistatic Interaction between Pnpla2 and Lipe Reveals New Pathways of Adipose Tissue Lipolysis. Cells 2019; 8:cells8050395. [PMID: 31035700 PMCID: PMC6563012 DOI: 10.3390/cells8050395] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/17/2019] [Accepted: 04/23/2019] [Indexed: 12/20/2022] Open
Abstract
White adipose tissue (WAT) lipolysis contributes to energy balance during fasting. Lipolysis can proceed by the sequential hydrolysis of triglycerides (TGs) by adipose triglyceride lipase (ATGL), then of diacylglycerols (DGs) by hormone-sensitive lipase (HSL). We showed that the combined genetic deficiency of ATGL and HSL in mouse adipose tissue produces a striking different phenotype from that of isolated ATGL deficiency, inconsistent with the linear model of lipolysis. We hypothesized that the mechanism might be functional redundancy between ATGL and HSL. To test this, the TG hydrolase activity of HSL was measured in WAT. HSL showed TG hydrolase activity. Then, to test ATGL for activity towards DGs, radiolabeled DGs were incubated with HSL-deficient lipid droplet fractions. The content of TG increased, suggesting DG-to-TG synthesis rather than DG hydrolysis. TG synthesis was abolished by a specific ATGL inhibitor, suggesting that ATGL functions as a transacylase when HSL is deficient, transferring an acyl group from one DG to another, forming a TG plus a monoglyceride (MG) that could be hydrolyzed by monoglyceride lipase. These results reveal a previously unknown physiological redundancy between ATGL and HSL, a mechanism for the epistatic interaction between Pnpla2 and Lipe. It provides an alternative lipolytic pathway, potentially important in patients with deficient lipolysis.
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Affiliation(s)
- Xiao Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Cong Cong Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Hao Yang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Krishnakant G Soni
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030, USA.
| | - Shu Pei Wang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Grant A Mitchell
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
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Bagherniya M, Butler AE, Barreto GE, Sahebkar A. The effect of fasting or calorie restriction on autophagy induction: A review of the literature. Ageing Res Rev 2018; 47:183-197. [PMID: 30172870 DOI: 10.1016/j.arr.2018.08.004] [Citation(s) in RCA: 167] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 12/13/2022]
Abstract
Autophagy is a lysosomal degradation process and protective housekeeping mechanism to eliminate damaged organelles, long-lived misfolded proteins and invading pathogens. Autophagy functions to recycle building blocks and energy for cellular renovation and homeostasis, allowing cells to adapt to stress. Modulation of autophagy is a potential therapeutic target for a diverse range of diseases, including metabolic conditions, neurodegenerative diseases, cancers and infectious diseases. Traditionally, food deprivation and calorie restriction (CR) have been considered to slow aging and increase longevity. Since autophagy inhibition attenuates the anti-aging effects of CR, it has been proposed that autophagy plays a substantive role in CR-mediated longevity. Among several stress stimuli inducers of autophagy, fasting and CR are the most potent non-genetic autophagy stimulators, and lack the undesirable side effects associated with alternative interventions. Despite the importance of autophagy, the evidence connecting fasting or CR with autophagy promotion has not previously been reviewed. Therefore, our objective was to weigh the evidence relating the effect of CR or fasting on autophagy promotion. We conclude that both fasting and CR have a role in the upregulation of autophagy, the evidence overwhelmingly suggesting that autophagy is induced in a wide variety of tissues and organs in response to food deprivation.
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Affiliation(s)
- Mohammad Bagherniya
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alexandra E Butler
- Diabetes Research Center, Qatar Biomedical Research Institute, Doha, Qatar
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, 9177948564, Iran.
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Of mice and men: The physiological role of adipose triglyceride lipase (ATGL). Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:880-899. [PMID: 30367950 PMCID: PMC6439276 DOI: 10.1016/j.bbalip.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) has been discovered 14 years ago and revised our view on intracellular triglyceride (TG) mobilization – a process termed lipolysis. ATGL initiates the hydrolysis of TGs to release fatty acids (FAs) that are crucial energy substrates, precursors for the synthesis of membrane lipids, and ligands of nuclear receptors. Thus, ATGL is a key enzyme in whole-body energy homeostasis. In this review, we give an update on how ATGL is regulated on the transcriptional and post-transcriptional level and how this affects the enzymes' activity in the context of neutral lipid catabolism. In depth, we highlight and discuss the numerous physiological functions of ATGL in lipid and energy metabolism. Over more than a decade, different genetic mouse models lacking or overexpressing ATGL in a cell- or tissue-specific manner have been generated and characterized. Moreover, pharmacological studies became available due to the development of a specific murine ATGL inhibitor (Atglistatin®). The identification of patients with mutations in the human gene encoding ATGL and their disease spectrum has underpinned the importance of ATGL in humans. Together, mouse models and human data have advanced our understanding of the physiological role of ATGL in lipid and energy metabolism in adipose and non-adipose tissues, and of the pathophysiological consequences of ATGL dysfunction in mice and men. Summary of mouse models with genetic or pharmacological manipulation of ATGL. Summary of patients with mutations in the human gene encoding ATGL. In depth discussion of the role of ATGL in numerous physiological processes in mice and men.
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Elander PH, Minina EA, Bozhkov PV. Autophagy in turnover of lipid stores: trans-kingdom comparison. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1301-1311. [PMID: 29309625 DOI: 10.1093/jxb/erx433] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/14/2017] [Indexed: 05/24/2023]
Abstract
Lipids and their cellular utilization are essential for life. Not only are lipids energy storage molecules, but their diverse structural and physical properties underlie various aspects of eukaryotic biology, such as membrane structure, signalling, and trafficking. In the ever-changing environment of cells, lipids, like other cellular components, are regularly recycled to uphold the housekeeping processes required for cell survival and organism longevity. The ways in which lipids are recycled, however, vary between different phyla. For example, animals and plants have evolved distinct lipid degradation pathways. The major cell recycling system, autophagy, has been shown to be instrumental for both differentiation of specialized fat storing-cells, adipocytes, and fat degradation in animals. Does plant autophagy play a similar role in storage and degradation of lipids? In this review, we discuss and compare implications of bulk autophagy and its selective route, lipophagy, in the turnover of lipid stores in animals, fungi, and plants.
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Affiliation(s)
- Pernilla H Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
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Sathyanarayan A, Mashek MT, Mashek DG. ATGL Promotes Autophagy/Lipophagy via SIRT1 to Control Hepatic Lipid Droplet Catabolism. Cell Rep 2017; 19:1-9. [PMID: 28380348 DOI: 10.1016/j.celrep.2017.03.026] [Citation(s) in RCA: 227] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/21/2016] [Accepted: 03/06/2017] [Indexed: 12/25/2022] Open
Abstract
Hepatic lipid droplet (LD) catabolism is thought to occur via cytosolic lipases such as adipose triglyceride lipase (ATGL) or through autophagy of LDs, a process known as lipophagy. We tested the potential interplay between these metabolic processes and its effects on hepatic lipid metabolism. We show that hepatic ATGL is both necessary and sufficient to induce both autophagy and lipophagy. Moreover, lipophagy is required for ATGL to promote LD catabolism and the subsequent oxidation of hydrolyzed fatty acids (FAs). Following previous work showing that ATGL promotes sirtuin 1 (SIRT1) activity, studies in liver-specific SIRT1-/- mice and in primary hepatocytes reveal that SIRT1 is required for ATGL-mediated induction of autophagy and lipophagy. Taken together, these studies show that ATGL-mediated signaling via SIRT1 promotes autophagy/lipophagy as a primary means to control hepatic LD catabolism and FA oxidation.
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Affiliation(s)
- Aishwarya Sathyanarayan
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA
| | - Mara T Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
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Xia B, Cai GH, Yang H, Wang SP, Mitchell GA, Wu JW. Adipose tissue deficiency of hormone-sensitive lipase causes fatty liver in mice. PLoS Genet 2017; 13:e1007110. [PMID: 29232702 PMCID: PMC5741266 DOI: 10.1371/journal.pgen.1007110] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 12/22/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023] Open
Abstract
Fatty liver is a major health problem worldwide. People with hereditary deficiency of hormone-sensitive lipase (HSL) are reported to develop fatty liver. In this study, systemic and tissue-specific HSL-deficient mice were used as models to explore the underlying mechanism of this association. We found that systemic HSL deficient mice developed fatty liver in an age-dependent fashion between 3 and 8 months of age. To further explore the mechanism of fatty liver in HSL deficiency, liver-specific HSL knockout mice were created. Surprisingly, liver HSL deficiency did not influence liver fat content, suggesting that fatty liver in HSL deficiency is not liver autonomous. Given the importance of adipose tissue in systemic triglyceride metabolism, we created adipose-specific HSL knockout mice and found that adipose HSL deficiency, to a similar extent as systemic HSL deficiency, causes age-dependent fatty liver in mice. Mechanistic study revealed that deficiency of HSL in adipose tissue caused inflammatory macrophage infiltrates, progressive lipodystrophy, abnormal adipokine secretion and systemic insulin resistance. These changes in adipose tissue were associated with a constellation of changes in liver: low levels of fatty acid oxidation, of very low density lipoprotein secretion and of triglyceride hydrolase activity, each favoring the development of hepatic steatosis. In conclusion, HSL-deficient mice revealed a complex interorgan interaction between adipose tissue and liver: the role of HSL in the liver is minimal but adipose tissue deficiency of HSL can cause age-dependent hepatic steatosis. Adipose tissue is a potential target for treating the hepatic steatosis of HSL deficiency. Fatty liver is a major complication of obesity and of type 2 diabetes mellitus. It carries a high risk of cirrhosis and liver cancer. In fatty liver, triglycerides accumulate to high levels in the cytoplasm of hepatocytes. Triglycerides are degraded by lipolysis, which has been most studied in fat cells where its three steps are catalyzed by different enzymes. The second step, hydrolysis of diglyceride to a monoglyceride, can be mediated by hormone-sensitive lipase (HSL). Patients with genetic deficiency of HSL have fatty liver. In this study, we found that systemic HSL deficient mice developed fatty liver with aging. To study the mechanism of steatosis, we made liver-specific HSL-deficient mice. Surprisingly, these mice had normal liver fat content. We then studied mice with HSL deficiency in adipose tissue. Adipose HSL-deficient mice developed hepatic steatosis to a similar extent as mice with systemic HSL deficiency, showing that adipose HSL deficiency is sufficient to cause fatty liver. Furthermore, like reported HSL-deficient humans, mice with adipose HSL deficiency had systemic insulin resistance, reduced fat mass and inflammation in fat tissue. Each of these is known to promote hepatic steatosis. Livers of adipose HSL-deficient mice showed low levels of hepatic fatty acid (FA) oxidation, of very low density lipoprotein (VLDL) secretion and of triglycerides (TG) hydrolase activity, each of which could contribute to fat accumulation in liver. Tissue-selective genetic alterations may help in identifying and understanding the tissues responsible for complex metabolic phenotypes like fatty liver. Our data suggest that at least in mice, strategies for treatment of fatty liver related to HSL deficiency should concentrate on adipose tissue.
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Affiliation(s)
- Bo Xia
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Guo He Cai
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Hao Yang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
| | - Shu Pei Wang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
| | - Grant A. Mitchell
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
- * E-mail: (JWW); (GAM)
| | - Jiang Wei Wu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
- * E-mail: (JWW); (GAM)
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Epistatic interaction between the lipase-encoding genes Pnpla2 and Lipe causes liposarcoma in mice. PLoS Genet 2017; 13:e1006716. [PMID: 28459858 PMCID: PMC5432192 DOI: 10.1371/journal.pgen.1006716] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 05/15/2017] [Accepted: 03/25/2017] [Indexed: 11/19/2022] Open
Abstract
Liposarcoma is an often fatal cancer of fat cells. Mechanisms of liposarcoma development are incompletely understood. The cleavage of fatty acids from acylglycerols (lipolysis) has been implicated in cancer. We generated mice with adipose tissue deficiency of two major enzymes of lipolysis, adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), encoded respectively by Pnpla2 and Lipe. Adipocytes from double adipose knockout (DAKO) mice, deficient in both ATGL and HSL, showed near-complete deficiency of lipolysis. All DAKO mice developed liposarcoma between 11 and 14 months of age. No tumors occurred in single knockout or control mice. The transcriptome of DAKO adipose tissue showed marked differences from single knockout and normal controls as early as 3 months. Gpnmb and G0s2 were among the most highly dysregulated genes in premalignant and malignant DAKO adipose tissue, suggesting a potential utility as early markers of the disease. Similar changes of GPNMB and G0S2 expression were present in a human liposarcoma database. These results show that a previously-unknown, fully penetrant epistatic interaction between Pnpla2 and Lipe can cause liposarcoma in mice. DAKO mice provide a promising model for studying early premalignant changes that lead to late-onset malignant disease. Liposarcoma is an often fatal adult-onset tumor of fat tissue. Lipolysis, the central pathway of fat tissue metabolism, has been implicated in cancer. We generated mice that were deficient in two key enzymes of lipolysis, adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL). Strikingly, all mice with combined ATGL and HSL deficiency developed liposarcoma by 11–14 months of age. No liposarcoma occurred in single knockout or normal controls. Transcriptome analysis revealed that a subset of genes is dysregulated by 3 months of age. Our study reveals a novel epistatic interaction in fat cells between these two lipase genes and that causes a unique form of liposarcoma in mice. The double knockout mice provide a novel tool to study the early stages of liposarcoma development, prognostic markers and preventive treatments.
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Mueller KM, Hartmann K, Kaltenecker D, Vettorazzi S, Bauer M, Mauser L, Amann S, Jall S, Fischer K, Esterbauer H, Müller TD, Tschöp MH, Magnes C, Haybaeck J, Scherer T, Bordag N, Tuckermann JP, Moriggl R. Adipocyte Glucocorticoid Receptor Deficiency Attenuates Aging- and HFD-Induced Obesity and Impairs the Feeding-Fasting Transition. Diabetes 2017; 66:272-286. [PMID: 27650854 DOI: 10.2337/db16-0381] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 09/14/2016] [Indexed: 11/13/2022]
Abstract
Glucocorticoids (GCs) are important regulators of systemic energy metabolism, and aberrant GC action is linked to metabolic dysfunctions. Yet, the extent to which normal and pathophysiological energy metabolism depend on the GC receptor (GR) in adipocytes remains unclear. Here, we demonstrate that adipocyte GR deficiency in mice significantly impacts systemic metabolism in different energetic states. Plasma metabolomics and biochemical analyses revealed a marked global effect of GR deficiency on systemic metabolite abundance and, thus, substrate partitioning in fed and fasted states. This correlated with a decreased lipolytic capacity of GR-deficient adipocytes under postabsorptive and fasting conditions, resulting from impaired signal transduction from β-adrenergic receptors to adenylate cyclase. Upon prolonged fasting, the impaired lipolytic response resulted in abnormal substrate utilization and lean mass wasting. Conversely, GR deficiency attenuated aging-/diet-associated obesity, adipocyte hypertrophy, and liver steatosis. Systemic glucose tolerance was improved in obese GR-deficient mice, which was associated with increased insulin signaling in muscle and adipose tissue. We conclude that the GR in adipocytes exerts central but diverging roles in the regulation of metabolic homeostasis depending on the energetic state. The adipocyte GR is indispensable for the feeding-fasting transition but also promotes adiposity and associated metabolic disorders in fat-fed and aged mice.
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Affiliation(s)
- Kristina M Mueller
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
| | - Kerstin Hartmann
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | | | - Sabine Vettorazzi
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Mandy Bauer
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Lea Mauser
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Sabine Amann
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Sigrid Jall
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) and German Center for Diabetes Research (DZD), Neuherberg, Germany
- Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Katrin Fischer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) and German Center for Diabetes Research (DZD), Neuherberg, Germany
- Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Harald Esterbauer
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) and German Center for Diabetes Research (DZD), Neuherberg, Germany
- Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) and German Center for Diabetes Research (DZD), Neuherberg, Germany
- Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Christoph Magnes
- HEALTH Institute for Biomedicine and Health Sciences, JOANNEUM RESEARCH, Forschungsgesellschaft mbH, Graz, Austria
| | | | - Thomas Scherer
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Natalie Bordag
- Center for Biomarker Research in Medicine, CBmed GmbH, Graz, Austria
| | - Jan P Tuckermann
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Richard Moriggl
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
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Sun C, Jiang L, Liu Y, Shen H, Weiss SJ, Zhou Y, Rui L. Adipose Snail1 Regulates Lipolysis and Lipid Partitioning by Suppressing Adipose Triacylglycerol Lipase Expression. Cell Rep 2016; 17:2015-2027. [PMID: 27851965 PMCID: PMC5131732 DOI: 10.1016/j.celrep.2016.10.070] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/25/2016] [Accepted: 10/19/2016] [Indexed: 12/14/2022] Open
Abstract
Lipolysis provides metabolic fuel; however, aberrant adipose lipolysis results in ectopic lipid accumulation and lipotoxicity. While adipose triacylglycerol lipase (ATGL) catalyzes the first step of lipolysis, its regulation is not fully understood. Here, we demonstrate that adipocyte Snail1 suppresses both ATGL expression and lipolysis. Adipose Snail1 levels are higher in fed mice than in fasted mice and higher in obese mice as opposed to lean mice. Insulin increases Snail1 levels in both murine and human adipocytes, wherein Snail1 binds to the ATGL promoter to repress its expression. Importantly, adipocyte-specific deletion of Snail1 increases adipose ATGL expression and lipolysis, resulting in decreased fat mass and increased liver fat content in mice fed either a normal chow diet or a high-fat diet. Thus, we have identified a Snail1-ATGL axis that regulates adipose lipolysis and fatty acid release, thereby governing lipid partitioning between adipose and non-adipose tissues.
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MESH Headings
- 3T3-L1 Cells
- Adipocytes, White/drug effects
- Adipocytes, White/metabolism
- Adipocytes, White/pathology
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Animals
- Cell Size/drug effects
- Diet, High-Fat
- Down-Regulation/drug effects
- Down-Regulation/genetics
- Epigenesis, Genetic/drug effects
- Fatty Liver/metabolism
- Fatty Liver/pathology
- Gene Deletion
- Humans
- Insulin/pharmacology
- Lipase/genetics
- Lipase/metabolism
- Lipolysis/drug effects
- Liver/drug effects
- Liver/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Obesity/metabolism
- Obesity/pathology
- Organ Specificity
- Promoter Regions, Genetic/genetics
- Snail Family Transcription Factors/metabolism
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Affiliation(s)
- Chengxin Sun
- School of Life Sciences, University of Northeast Normal University, Changchun 130024, China; Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Lin Jiang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yan Liu
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Hong Shen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Stephen J Weiss
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yifa Zhou
- School of Life Sciences, University of Northeast Normal University, Changchun 130024, China.
| | - Liangyou Rui
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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