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Kolleritsch S, Pajed L, Tilp A, Hois V, Potoschnig I, Kien B, Diwoky C, Hoefler G, Schoiswohl G, Haemmerle G. Adverse cardiac remodeling augments adipose tissue ß-adrenergic signaling and lipolysis counteracting diet-induced obesity. J Biol Chem 2023:104788. [PMID: 37150323 DOI: 10.1016/j.jbc.2023.104788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 03/06/2023] [Accepted: 04/25/2023] [Indexed: 05/09/2023] Open
Abstract
Cardiac triacylglycerol (TAG) accumulation is a common characteristic of obesity and type 2 diabetes and strongly correlates with heart morbidity and mortality. We have previously shown that cardiomyocyte-specific Perilipin 5 overexpression (Plin5-Tg) provokes significant cardiac steatosis via lowering cardiac lipolysis and fatty acid (FA) oxidation. In strong contrast to cardiac steatosis and lethal heart dysfunction in Adipose triglyceride lipase deficiency, Plin5-Tg mice do not develop heart dysfunction and show a normal life span on chow diet. This finding prompted us to study heart function and energy metabolism in Plin5-Tg mice fed high-fat diet (HFD). Plin5-Tg mice showed adverse cardiac remodeling on HFD with heart function only being compromised in one-year-old mice, likely due to reduced cardiac FA uptake, thereby delaying deleterious cardiac lipotoxicity. Notably, Plin5-Tg mice were less obese and protected from glucose intolerance on HFD. Changes in cardiac energy catabolism in Plin5-Tg mice increased ß-adrenergic signaling, lipolytic and thermogenic protein expression in adipose tissue ultimately counteracting HFD-induced obesity. Acute cold exposure further augmented ß-adrenergic signaling in Plin5-Tg mice, whereas housing at thermoneutrality did not protect Plin5-Tg mice from HFD-induced obesity albeit blood glucose and insulin levels remained low in transgenic mice. Overall, our data suggest that the limited capacity for myocardial FA oxidation on HFD increases cardiac stress in Plin5-Tg mice, thereby stimulating adipose tissue ß-adrenergic signaling, TAG catabolism, and thermogenesis. However, long-term HFD-mediated metabolic stress causes contractile dysfunction in Plin5-Tg mice, which emphasizes the importance of a carefully controlled dietary regime in patients with cardiac steatosis and hypertrophy.
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Affiliation(s)
| | - Laura Pajed
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Anna Tilp
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Victoria Hois
- Division of Endocrinology and Diabetology, Medical University of Graz, 8010 Graz, Austria
| | | | - Benedikt Kien
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Clemens Diwoky
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Gerald Hoefler
- Diagnostic & Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria; BioTechMed, Graz, 8010 Graz, Austria
| | - Gabriele Schoiswohl
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; BioTechMed, Graz, 8010 Graz, Austria; Department of Pharmacology and Toxicology, University of Graz, 8010 Graz, Austria.
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
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2
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Chen S, Huang X. Cytosolic lipolysis in non-adipose tissues: energy provision and beyond. FEBS J 2022; 289:7385-7398. [PMID: 34407292 DOI: 10.1111/febs.16161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/18/2021] [Accepted: 08/17/2021] [Indexed: 12/16/2022]
Abstract
Cytosolic lipolysis is a well-defined biochemical process that plays important roles in the mobilization of stored neutral lipids. Lipid turnover, regulated by cytosolic lipolysis, has been extensively studied in adipose tissue, liver, and muscle. The storage and utilization of neutral lipids is a basic function of most, if not all, tissues and cells. In this review, we focus on the functions of cytosolic lipolysis mainly in non-adipose tissues and in several physiological processes, including cancer, longevity, and pathogen infection. The mechanisms underlying the impact of cytosolic lipolysis on these events will be discussed. Detailed understanding of cytosolic lipolysis in both adipose and non-adipose tissues will have implications for future clinical translation.
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Affiliation(s)
- 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
| | - Xun Huang
- 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
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3
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Schratter M, Lass A, Radner FPW. ABHD5-A Regulator of Lipid Metabolism Essential for Diverse Cellular Functions. Metabolites 2022; 12:1015. [PMID: 36355098 PMCID: PMC9694394 DOI: 10.3390/metabo12111015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/19/2022] [Accepted: 10/23/2022] [Indexed: 11/12/2023] Open
Abstract
The α/β-Hydrolase domain-containing protein 5 (ABHD5; also known as comparative gene identification-58, or CGI-58) is the causative gene of the Chanarin-Dorfman syndrome (CDS), a disorder mainly characterized by systemic triacylglycerol accumulation and a severe defect in skin barrier function. The clinical phenotype of CDS patients and the characterization of global and tissue-specific ABHD5-deficient mouse strains have demonstrated that ABHD5 is a crucial regulator of lipid and energy homeostasis in various tissues. Although ABHD5 lacks intrinsic hydrolase activity, it functions as a co-activating enzyme of the patatin-like phospholipase domain-containing (PNPLA) protein family that is involved in triacylglycerol and glycerophospholipid, as well as sphingolipid and retinyl ester metabolism. Moreover, ABHD5 interacts with perilipins (PLINs) and fatty acid-binding proteins (FABPs), which are important regulators of lipid homeostasis in adipose and non-adipose tissues. This review focuses on the multifaceted role of ABHD5 in modulating the function of key enzymes in lipid metabolism.
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Affiliation(s)
- Margarita Schratter
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Achim Lass
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, 8010 Graz, Austria
| | - Franz P. W. Radner
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
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4
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Bednarski TK, Duda MK, Dobrzyn P. Alterations of Lipid Metabolism in the Heart in Spontaneously Hypertensive Rats Precedes Left Ventricular Hypertrophy and Cardiac Dysfunction. Cells 2022; 11:cells11193032. [PMID: 36230994 PMCID: PMC9563594 DOI: 10.3390/cells11193032] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/22/2022] [Accepted: 09/26/2022] [Indexed: 11/22/2022] Open
Abstract
Disturbances in cardiac lipid metabolism are associated with the development of cardiac hypertrophy and heart failure. Spontaneously hypertensive rats (SHRs), a genetic model of primary hypertension and pathological left ventricular (LV) hypertrophy, have high levels of diacylglycerols in cardiomyocytes early in development. However, the exact effect of lipids and pathways that are involved in their metabolism on the development of cardiac dysfunction in SHRs is unknown. Therefore, we used SHRs and Wistar Kyoto (WKY) rats at 6 and 18 weeks of age to analyze the impact of perturbations of processes that are involved in lipid synthesis and degradation in the development of LV hypertrophy in SHRs with age. Triglyceride levels were higher, whereas free fatty acid (FA) content was lower in the LV in SHRs compared with WKY rats. The expression of de novo FA synthesis proteins was lower in cardiomyocytes in SHRs compared with corresponding WKY controls. The higher expression of genes that are involved in TG synthesis in 6-week-old SHRs may explain the higher TG content in these rats. Adenosine monophosphate-activated protein kinase phosphorylation and peroxisome proliferator-activated receptor α protein content were lower in cardiomyocytes in 18-week-old SHRs, suggesting a lower rate of β-oxidation. The decreased protein content of α/β-hydrolase domain-containing 5, adipose triglyceride lipase (ATGL) activator, and increased content of G0/G1 switch protein 2, ATGL inhibitor, indicating a lower rate of lipolysis in the heart in SHRs. In conclusion, the present study showed that the development of LV hypertrophy and myocardial dysfunction in SHRs is associated with triglyceride accumulation, attributable to a lower rate of lipolysis and β-oxidation in cardiomyocytes.
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Affiliation(s)
- Tomasz K. Bednarski
- Laboratory of Molecular Medical Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Monika K. Duda
- Centre of Postgraduate Medical Education, Department of Clinical Physiology, 01-813 Warsaw, Poland
| | - Pawel Dobrzyn
- Laboratory of Molecular Medical Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
- Correspondence:
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5
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Ghanem M, Lewis GF, Xiao C. Recent advances in cytoplasmic lipid droplet metabolism in intestinal enterocyte. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159197. [PMID: 35820577 DOI: 10.1016/j.bbalip.2022.159197] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 06/03/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
Processing of dietary fats in the intestine is a highly regulated process that influences whole-body energy homeostasis and multiple physiological functions. Dysregulated lipid handling in the intestine leads to dyslipidemia and atherosclerotic cardiovascular disease. In intestinal enterocytes, lipids are incorporated into lipoproteins and cytoplasmic lipid droplets (CLDs). Lipoprotein synthesis and CLD metabolism are inter-connected pathways with multiple points of regulation. This review aims to highlight recent advances in the regulatory mechanisms of lipid processing in the enterocyte, with particular focus on CLDs. In-depth understanding of the regulation of lipid metabolism in the enterocyte may help identify therapeutic targets for the treatment and prevention of metabolic disorders.
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Affiliation(s)
- Murooj Ghanem
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Gary F Lewis
- Departments of Medicine and Physiology, University of Toronto, and University Health Network, Toronto, ON, Canada
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
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6
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Zhang H, Gao X, Chen P, Wang H. Protective Effects of Tiaoganquzhi Decoction in Treating inflammatory Injury of Nonalcoholic Fatty liver Disease by Promoting CGI-58 and Inhibiting Expression of NLRP3 Inflammasome. Front Pharmacol 2022; 13:851267. [PMID: 35586044 PMCID: PMC9108379 DOI: 10.3389/fphar.2022.851267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 04/08/2022] [Indexed: 12/14/2022] Open
Abstract
Tiaoganquzhi Decoction (TGQZD) is a traditional Chinese herbal formulation demonstrated to be a clinically effective treatment for nonalcoholic fatty liver disease (NAFLD), although details concerning its clinical mechanism are poor. This study aimed to explore the mechanism of TGQZD on improvement of inflammatory damage and dyslipidemia caused by NAFLD through the CGI-58/ROS/NLRP3 inflammasome pathway. In our research, the in vivo protective effects of TGQZD on HFD-induced liver injury in rats and in vitro using lipopolysaccharide (LPS)+palmitate (PA)-stimulated HepG-2 cells model. Histological changes were evaluated by hematoxylin-eosin and Oil Red O staining. Inflammatory cytokines and protein expression were analyzed by ELISA, Real time PCR and western blotting. Liver function, blood lipids, free fatty acids (FFA), and reactive oxygen species (ROS) were determined by biochemical detection. Our results indicated that TGQZD exhibited anti-inflammatory activity, reduced the severity of NAFLD and ameliorated the pathological changes. Further, TGQZD improved liver function and lipid metabolism in NAFLD rats. TGQZD lowered serum aspartate aminotransferase, alanine aminotransferase, triglyceride, and total cholesterol levels. TGQZD suppressed the formulation of FFA and ROS. It also reduced the expression and release of the inflammatory cytokine interleukin-1β by promoting CGI-58 expression and inhibiting the expression of FFA, TNF-α, and the NLRP3 inflammasome induced by ROS. TGQZD exhibited anti-inflammatory effects via the CGI-58, ROS and NLRP3 inflammasome pathway in vivo and in vitro, respectively. Our findings demonstrated that TGQZD is a useful and effective therapeutic agent for treating NAFLD via promotion of CGI-58 to inhibit the expression of ROS-induced NLRP3 inflammasome.
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Affiliation(s)
- Huicun Zhang
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
- Beijing Institute of Chinese Medicine, Beijing, China
- *Correspondence: Huicun Zhang,
| | - Xiang Gao
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | | | - Hongbing Wang
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
- Beijing Hospital of Traditional Chinese Medicine Yanqing Hospital, Beijing, China
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7
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Wikramanayake TC, Chéret J, Sevilla A, Birch-Machin M, Paus R. Targeting mitochondria in dermatological therapy: Beyond oxidative damage and skin aging. Expert Opin Ther Targets 2022; 26:233-259. [PMID: 35249436 DOI: 10.1080/14728222.2022.2049756] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION The analysis of the role of the mitochondria in oxidative damage and skin aging is a significant aspect of dermatological research. Mitochondria generate most reactive oxygen species (ROS); however, excessive ROS are cytotoxic and DNA-damaging and promote (photo-)aging. ROS also possesses key physiological and regulatory functions and mitochondrial dysfunction is prominent in several skin diseases including skin cancers. Although many standard dermatotherapeutics modulate mitochondrial function, dermatological therapy rarely targets the mitochondria. Accordingly, there is a rationale for "mitochondrial dermatology"-based approaches to be applied to therapeutic research. AREAS COVERED This paper examines the functions of mitochondria in cutaneous physiology beyond energy (ATP) and ROS production. Keratinocyte differentiation and epidermal barrier maintenance, appendage morphogenesis and homeostasis, photoaging and skin cancer are considered. Based on related PubMed search results, the paper evaluates thyroid hormones, glucocorticoids, Vitamin D3 derivatives, retinoids, cannabinoid receptor agonists, PPARγ agonists, thyrotropin, and thyrotropin-releasing hormone as instructive lead compounds. Moreover, the mitochondrial protein MPZL3 as a promising new drug target for future "mitochondrial dermatology" is highlighted. EXPERT OPINION Future dermatological therapeutic research should have a mitochondrial medicine emphasis. Focusing on selected lead agents, protein targets, in silico drug design, and model diseases will fertilize a mito-centric approach.
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Affiliation(s)
- Tongyu C Wikramanayake
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A.,Molecular Cell and Developmental Biology Program, University of Miami Miller School of Medicine, Miami, FL, U.S.A
| | - Jérémy Chéret
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A
| | - Alec Sevilla
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A
| | - Mark Birch-Machin
- Dermatological Sciences, Translational and Clinical Research Institute, and The UK National Innovation Centre for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Ralf Paus
- Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, U.S.A.,Monasterium Laboratory, Münster, Germany.,Centre for Dermatology Research, University of Manchester, and NIHR Manchester Biomedical Research Centre, Manchester, UK
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8
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Lipid droplets associated perilipins protein insights into finding a therapeutic target approach to cure non-alcoholic fatty liver disease (NAFLD). FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2022. [DOI: 10.1186/s43094-021-00395-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Abstract
Background
Non-alcoholic fatty liver disease (NAFLD) is now the most common form of chronic liver disease in the world, and it’s linked to a slew of other risk factors including diabetes, obesity, dysbiosis and inflammatory bowel disease. More than 30 years ago, a patient was diagnosed with fatty liver with excessive fat accumulation in hepatocytes, a disorder known as hepatosteatosis. There will be no promising therapeutic medicines available from 1980 to 2021 which can reverse the fatty liver to normal liver state. In this review, we highlighted on lipid droplet associated protein which play a major role in accumulation of fat in liver cells and how these cellular pathway could be a promising therapeutic approach to treat the fatty liver disease.
Main body
Over the last few decades, Western countries follow a high-fat diet and change their lifestyle pattern due to certain metabolic disorders prevalence rate is very high all over the world. NAFLD is a major health issue and burden globally nowadays. Researchers are trying to find out the potential therapeutic target to combat the disease. The exact pathophysiology of the disease is still unclear. In the present decades. There is no Food and Drug Administration approved drugs are available to reverse the chronic condition of the disease. Based on literature survey, lipid droplets and their associated protein like perilipins play an eminent role in body fat regulation. In this review, we explain all types of perilipins such as perilipin1-5 (PLIN1-5) and their role in the pathogenesis of fatty liver which will be helpful to find the novel pharmacological target to treat the fatty liver.
Conclusion
In this review, majorly focussed on how fat is get deposited into hepatocytes follow the cellular signalling involved during lipid droplet biogenesis and leads to NAFLD. However, up to date still there mechanism of action is unclear. In this review, we hypothesized that lipid droplets associated proteins like perilipins could be better pharmacological target to reverse the chronic stage of fatty liver disease and how these lipid droplets associated proteins hide a clue to maintain the normal lipid homeostasis in the human body.
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9
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Huang W, Gao F, Zhang Y, Chen T, Xu C. Lipid Droplet-Associated Proteins in Cardiomyopathy. ANNALS OF NUTRITION AND METABOLISM 2021; 78:1-13. [PMID: 34856540 DOI: 10.1159/000520122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 10/08/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND The heart requires a high rate of fatty-acid oxidation (FAO) to meet its energy needs. Neutral lipids are the main source of energy for the heart and are stored in lipid droplets (LDs), which are cytosolic organelles that primarily serve to store neutral lipids and regulate cellular lipid metabolism. LD-associated proteins (LDAPs) are proteins either located on the surface of the LDs or reside in the cytosol and contribute to lipid metabolism. Therefore, abnormal cardiac lipid accumulation or FAO can alter the redox state of the heart, resulting in cardiomyopathy, a group of diseases that negatively affect the myocardial function, thereby leading to heart failure and even cardiac death. SUMMARY LDs, along with LDAPs, are pivotal for modulating heart lipid homeostasis. The proper cardiac development and the maintenance of its normal function depend largely on lipid homeostasis regulated by LDs and LDAPs. Overexpression or deletion of specific LDAPs can trigger myocardial dysfunction and may contribute to the development of cardiomyopathy. Extensive connections and interactions may also exist between LDAPs. Key Message: In this review, the various mechanisms involved in LDAP-mediated regulation of lipid metabolism, the association between cardiac development and lipid metabolism, as well as the role of LDAPs in cardiomyopathy progression are discussed.
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Affiliation(s)
- Weiwei Huang
- Obstetrics and Gynecology Hospital, Fudan University, Shanghai, China.,Department of Physiology and Pathophysiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Fei Gao
- Department of Physiology and Pathophysiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yuting Zhang
- Department of Physiology and Pathophysiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Tianhui Chen
- Department of Ophthalmology and Vision Science, Eye and ENT Hospital of Fudan University, Shanghai, China.,Key Laboratory of Myopia of State Health Ministry, and Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, China
| | - Chen Xu
- Department of Physiology and Pathophysiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Fudan University, Shanghai, China
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10
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Cardiac-specific CGI-58 deficiency activates the ER stress pathway to promote heart failure in mice. Cell Death Dis 2021; 12:1003. [PMID: 34702801 PMCID: PMC8548506 DOI: 10.1038/s41419-021-04282-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 09/28/2021] [Accepted: 10/04/2021] [Indexed: 11/09/2022]
Abstract
Excess myocardial triacylglycerol accumulation (i.e., cardiac steatosis) impairs heart function, suggesting that enzymes promoting triacylglycerol metabolism exert essential regulatory effects on heart function. Comparative gene identification 58 (CGI-58) is a key enzyme that promotes the hydrolysis of triglycerides by activating adipose triglyceride lipase and plays a protective role in maintaining heart function. In this study, the effects of CGI-58 on heart function and the underlying mechanism were investigated using cardiac-specific CGI58-knockout mice (CGI-58cko mice). Echocardiography and pathological staining were performed to detect changes in the structure and function of the heart. Proteomic profiling, immunofluorescent staining, western blotting, and real-time PCR were used to evaluate molecular changes. In CGI-58cko mice, we detected cardiac hypertrophic remodeling and heart failure associated with excessive cardiac lipid accumulation, ROS production, and decreased expression of regulators of fatty acid metabolism. These changes were markedly attenuated in CGI-58cko mice injected with rAAV9-CGI58. A quantitative proteomics analysis revealed significant increases in the expression of ER stress-related proteins and decreases in proteins related to fatty acid and amino acid metabolism in the hearts of CGI-58cko mice. Furthermore, the inhibition of ER stress by the inhibitor 4-PBA improved mitochondrial dysfunction, reduced oxidative stress, and reversed cardiac remodeling and dysfunction in cultured cardiomyocytes or in CGI-58cko mice. Our results suggested that CGI-58 is essential for the maintenance of heart function by reducing lipid accumulation and ER stress in cardiomyocytes, providing a new therapeutic target for cardiac steatosis and dysfunction.
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11
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Kolleritsch S, Kien B, Schoiswohl G, Diwoky C, Schreiber R, Heier C, Maresch LK, Schweiger M, Eichmann TO, Stryeck S, Krenn P, Tomin T, Schittmayer M, Kolb D, Rülicke T, Hoefler G, Wolinski H, Madl T, Birner-Gruenberger R, Haemmerle G. Low cardiac lipolysis reduces mitochondrial fission and prevents lipotoxic heart dysfunction in Perilipin 5 mutant mice. Cardiovasc Res 2020; 116:339-352. [PMID: 31166588 PMCID: PMC7338219 DOI: 10.1093/cvr/cvz119] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 02/14/2019] [Accepted: 05/02/2019] [Indexed: 12/12/2022] Open
Abstract
AIMS Lipotoxic cardiomyopathy in diabetic and obese patients typically encompasses increased cardiac fatty acid (FA) uptake eventually surpassing the mitochondrial oxidative capacity. Lowering FA utilization via inhibition of lipolysis represents a strategy to counteract the development of lipotoxic heart dysfunction. However, defective cardiac triacylglycerol (TAG) catabolism and FA oxidation in humans (and mice) carrying mutated ATGL alleles provokes lipotoxic heart dysfunction questioning a therapeutic approach to decrease cardiac lipolysis. Interestingly, decreased lipolysis via cardiac overexpression of Perilipin 5 (Plin5), a binding partner of ATGL, is compatible with normal heart function and lifespan despite massive cardiac lipid accumulation. Herein, we decipher mechanisms that protect Plin5 transgenic mice from the development of heart dysfunction. METHODS AND RESULTS We generated mice with cardiac-specific overexpression of Plin5 encoding a serine-155 to alanine exchange (Plin5-S155A) of the protein kinase A phosphorylation site, which has been suggested as a prerequisite to stimulate lipolysis and may play a crucial role in the preservation of heart function. Plin5-S155A mice showed a substantial increase in cardiac TAG and ceramide levels, which was comparable to mice overexpressing non-mutated Plin5. Lipid accumulation was compatible with normal heart function even under mild stress. Plin5-S155A mice showed reduced cardiac FA oxidation but normal ATP production and changes in the Plin5-S155A phosphoproteome compared to Plin5 transgenic mice. Interestingly, mitochondrial recruitment of dynamin-related protein 1 (Drp1) was markedly reduced in cardiac muscle of Plin5-S155A and Plin5 transgenic mice accompanied by decreased phosphorylation of mitochondrial fission factor, a mitochondrial receptor of Drp1. CONCLUSIONS This study suggests that low cardiac lipolysis is associated with reduced mitochondrial fission and may represent a strategy to combat the development of lipotoxic heart dysfunction.
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Affiliation(s)
- Stephanie Kolleritsch
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Benedikt Kien
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Gabriele Schoiswohl
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Clemens Diwoky
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Lisa Katharina Maresch
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Thomas O Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria.,Center for Explorative Lipidomics, BioTechMed-Graz, 8010 Graz, Austria
| | - Sarah Stryeck
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria.,Omics Center Graz, BioTechMed-Graz, 8010 Graz, Austria
| | - Petra Krenn
- Omics Center Graz, BioTechMed-Graz, 8010 Graz, Austria.,Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria
| | - Tamara Tomin
- Omics Center Graz, BioTechMed-Graz, 8010 Graz, Austria.,Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria
| | - Matthias Schittmayer
- Omics Center Graz, BioTechMed-Graz, 8010 Graz, Austria.,Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria
| | - Dagmar Kolb
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, 8010 Graz, Austria
| | - Thomas Rülicke
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Gerald Hoefler
- Diagnostic & Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Tobias Madl
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria.,Omics Center Graz, BioTechMed-Graz, 8010 Graz, Austria
| | - Ruth Birner-Gruenberger
- Omics Center Graz, BioTechMed-Graz, 8010 Graz, Austria.,Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
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12
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Korbelius M, Vujic N, Sachdev V, Obrowsky S, Rainer S, Gottschalk B, Graier WF, Kratky D. ATGL/CGI-58-Dependent Hydrolysis of a Lipid Storage Pool in Murine Enterocytes. Cell Rep 2020; 28:1923-1934.e4. [PMID: 31412256 PMCID: PMC6713565 DOI: 10.1016/j.celrep.2019.07.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 03/29/2019] [Accepted: 07/11/2019] [Indexed: 12/22/2022] Open
Abstract
As circulating lipid levels are balanced by the rate of lipoprotein release and clearance from the plasma, lipid absorption in the small intestine critically contributes to the maintenance of whole-body lipid homeostasis. Within enterocytes, excessive triglycerides are transiently stored as cytosolic lipid droplets (cLDs), and their mobilization sustains lipid supply during interprandial periods. Using mice lacking adipose triglyceride lipase (ATGL) and its coactivator comparative gene identification-58 (CGI-58) exclusively in the intestine (intestine-specific double KO [iDKO]), we show that ATGL/CGI-58 are not involved in providing substrates for chylomicron synthesis. Massive intestinal cLD accumulation in iDKO mice independent of dietary lipids together with inefficient lipid incorporation into cLDs in the early absorption phase demonstrate the existence of a secretion/re-uptake cycle, corroborating the availability of two diverse cLD pools. This study identified ATGL/CGI-58 as critical players in the catabolism of basolaterally (blood) derived lipids and highlights the necessity to modify the current model of intestinal lipid metabolism.
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Affiliation(s)
- Melanie Korbelius
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Nemanja Vujic
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Vinay Sachdev
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Sascha Obrowsky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Silvia Rainer
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Benjamin Gottschalk
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria; BioTechMed-Graz, 8010 Graz, Styria, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Styria, Austria; BioTechMed-Graz, 8010 Graz, Styria, Austria.
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13
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Sreedhar A, Aguilera-Aguirre L, Singh KK. Mitochondria in skin health, aging, and disease. Cell Death Dis 2020; 11:444. [PMID: 32518230 PMCID: PMC7283348 DOI: 10.1038/s41419-020-2649-z] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 02/08/2023]
Abstract
The skin is a high turnover organ, and its constant renewal depends on the rapid proliferation of its progenitor cells. The energy requirement for these metabolically active cells is met by mitochondrial respiration, an ATP generating process driven by a series of protein complexes collectively known as the electron transport chain (ETC) that is located on the inner membrane of the mitochondria. However, reactive oxygen species (ROS) like superoxide, singlet oxygen, peroxides are inevitably produced during respiration and disrupt macromolecular and cellular structures if not quenched by the antioxidant system. The oxidative damage caused by mitochondrial ROS production has been established as the molecular basis of multiple pathophysiological conditions, including aging and cancer. Not surprisingly, the mitochondria are the primary organelle affected during chronological and UV-induced skin aging, the phenotypic manifestations of which are the direct consequence of mitochondrial dysfunction. Also, deletions and other aberrations in the mitochondrial DNA (mtDNA) are frequent in photo-aged skin and skin cancer lesions. Recent studies have revealed a more innate role of the mitochondria in maintaining skin homeostasis and pigmentation, which are affected when the essential mitochondrial functions are impaired. Some common and rare skin disorders have a mitochondrial involvement and include dermal manifestations of primary mitochondrial diseases as well as congenital skin diseases caused by damaged mitochondria. With studies increasingly supporting the close association between mitochondria and skin health, its therapeutic targeting in the skin-either via an ATP production boost or free radical scavenging-has gained attention from clinicians and aestheticians alike. Numerous bioactive compounds have been identified that improve mitochondrial functions and have proved effective against aged and diseased skin. In this review, we discuss the essential role of mitochondria in regulating normal and abnormal skin physiology and the possibility of targeting this organelle in various skin disorders.
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Affiliation(s)
| | | | - Keshav K Singh
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
- Integartive Center For Aging Research and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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14
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Lundquist PK, Shivaiah KK, Espinoza-Corral R. Lipid droplets throughout the evolutionary tree. Prog Lipid Res 2020; 78:101029. [PMID: 32348789 DOI: 10.1016/j.plipres.2020.101029] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/11/2020] [Accepted: 04/18/2020] [Indexed: 12/11/2022]
Abstract
Intracellular lipid droplets are utilized for lipid storage and metabolism in organisms as evolutionarily diverse as animals, fungi, plants, bacteria, and archaea. These lipid droplets demonstrate great diversity in biological functions and protein and lipid compositions, yet fundamentally share common molecular and ultrastructural characteristics. Lipid droplet research has been largely fragmented across the diversity of lipid droplet classes and sub-classes. However, we suggest that there is great potential benefit to the lipid community in better integrating the lipid droplet research fields. To facilitate such integration, we survey the protein and lipid compositions, functional roles, and mechanisms of biogenesis across the breadth of lipid droplets studied throughout the natural world. We depict the big picture of lipid droplet biology, emphasizing shared characteristics and unique differences seen between different classes. In presenting the known diversity of lipid droplets side-by-side it becomes necessary to offer for the first time a consistent system of categorization and nomenclature. We propose a division into three primary classes that reflect their sub-cellular location: i) cytoplasmic lipid droplets (CYTO-LDs), that are present in the eukaryotic cytoplasm, ii) prokaryotic lipid droplets (PRO-LDs), that exist in the prokaryotic cytoplasm, and iii) plastid lipid droplets (PL-LDs), that are found in plant plastids, organelles of photosynthetic eukaryotes. Within each class there is a remarkable array of sub-classes displaying various sizes, shapes and compositions. A more integrated lipid droplet research field will provide opportunities to better build on discoveries and accelerate the pace of research in ways that have not been possible.
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Affiliation(s)
- Peter K Lundquist
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA.
| | - Kiran-Kumar Shivaiah
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
| | - Roberto Espinoza-Corral
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
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15
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Kintscher U, Foryst-Ludwig A, Haemmerle G, Zechner R. The Role of Adipose Triglyceride Lipase and Cytosolic Lipolysis in Cardiac Function and Heart Failure. CELL REPORTS MEDICINE 2020; 1:100001. [PMID: 33205054 PMCID: PMC7659492 DOI: 10.1016/j.xcrm.2020.100001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Heart failure is one of the leading causes of death worldwide. New therapeutic concepts are urgently required to lower the burden of heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), the two major forms of heart failure. Lipolytic processes are induced during the development of heart failure and occur in adipose tissue and multiple organs, including the heart. Increasing evidence suggests that cellular lipolysis, in particular, adipose triglyceride lipase (ATGL) activity, has an important function in cardiac (patho)physiology. This review summarizes the crucial role of cellular lipolysis for normal cardiac function and for the development of HFrEF and HFpEF. We discuss the most relevant pre-clinical studies and elaborate on the cardiac consequences of non-myocardial and myocardial lipolysis modulation. Finally, we critically analyze the therapeutic importance of pharmacological ATGL inhibition as a potential treatment option for HFrEF and/or HFpEF in the future.
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Affiliation(s)
- Ulrich Kintscher
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Corresponding author
| | - Anna Foryst-Ludwig
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Einstein BIH Visiting Fellow, Berlin Institute of Health, and Charité - Universitätsmedizin Berlin, Berlin, Germany
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16
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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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17
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Jebessa ZH, Shanmukha KD, Dewenter M, Lehmann LH, Xu C, Schreiter F, Siede D, Gong XM, Worst BC, Federico G, Sauer SW, Fischer T, Wechselberger L, Müller OJ, Sossalla S, Dieterich C, Most P, Gröne HJ, Moro C, Oberer M, Haemmerle G, Katus HA, Tyedmers J, Backs J. The lipid droplet-associated protein ABHD5 protects the heart through proteolysis of HDAC4. Nat Metab 2019; 1:1157-1167. [PMID: 31742248 PMCID: PMC6861130 DOI: 10.1038/s42255-019-0138-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Catecholamines stimulate the first step of lipolysis by PKA-dependent release of the lipid droplet-associated protein ABHD5 from perilipin to co-activate the lipase ATGL. Here, we unmask a yet unrecognized proteolytic and cardioprotective function of ABHD5. ABHD5 acts in vivo and in vitro as a serine protease cleaving HDAC4. Through the production of an N-terminal polypeptide of HDAC4 (HDAC4-NT), ABHD5 inhibits MEF2-dependent gene expression and thereby controls glucose handling. ABHD5-deficiency leads to neutral lipid storage disease in mice. Cardiac-specific gene therapy of HDAC4-NT does not protect from intra-cardiomyocyte lipid accumulation but strikingly from heart failure, thereby challenging the concept of lipotoxicity-induced heart failure. ABHD5 levels are reduced in failing human hearts and murine transgenic ABHD5 expression protects from pressure-overload induced heart failure. These findings represent a conceptual advance by connecting lipid with glucose metabolism through HDAC4 proteolysis and enable new translational approaches to treat cardiometabolic disease.
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Affiliation(s)
- Zegeye H Jebessa
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Kumar D Shanmukha
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Matthias Dewenter
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Lorenz H Lehmann
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Chang Xu
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Friederike Schreiter
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Dominik Siede
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Xue-Min Gong
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Barbara C Worst
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
- Pediatric Glioma Research Group, Hopp Children's Cancer Center Heidelberg (KiTZ) and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Giuseppina Federico
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany
| | - Sven W Sauer
- Department of General Pediatrics, Division of Inborn Metabolic Diseases, University Children's Hospital, Heidelberg, Germany
| | - Tamas Fischer
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Lisa Wechselberger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Oliver J Müller
- Department of Internal Medicine III, University of Kiel, Kiel, Germany
| | - Samuel Sossalla
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Christoph Dieterich
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Patrick Most
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Herrmann-Josef Gröne
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany
- Institute for Pathology and Nephropathology, University Hospital Marburg, Marburg, Germany
| | - Cedric Moro
- INSERM, UMR1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases, Toulouse, France
| | - Monika Oberer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Hugo A Katus
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Jens Tyedmers
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Johannes Backs
- Institute of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany.
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18
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Hehlert P, Hofferek V, Heier C, Eichmann TO, Riedel D, Rosenberg J, Takaćs A, Nagy HM, Oberer M, Zimmermann R, Kühnlein RP. The α/β-hydrolase domain-containing 4- and 5-related phospholipase Pummelig controls energy storage in Drosophila. J Lipid Res 2019; 60:1365-1378. [PMID: 31164391 DOI: 10.1194/jlr.m092817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/03/2019] [Indexed: 01/05/2023] Open
Abstract
Triglycerides (TGs) are the main energy storage form that accommodates changing organismal energy demands. In Drosophila melanogaster, the TG lipase Brummer is centrally important for body fat mobilization. Its gene brummer (bmm) encodes the ortholog of mammalian adipose TG lipase, which becomes activated by α/β-hydrolase domain-containing 5 (ABHD5/CGI-58), one member of the paralogous gene pair, α/β-hydrolase domain-containing 4 (ABHD4) and ABHD5 In Drosophila, the pummelig (puml) gene encodes the single sequence-related protein to mammalian ABHD4/ABHD5 with unknown function. We generated puml deletion mutant flies, that were short-lived as a result of lipid metabolism changes, stored excess body fat at the expense of glycogen, and exhibited ectopic fat storage with altered TG FA profile in the fly kidneys, called Malpighian tubules. TG accumulation in puml mutants was not associated with increased food intake but with elevated lipogenesis; starvation-induced lipid mobilization remained functional. Despite its structural similarity to mammalian ABHD5, Puml did not stimulate TG lipase activity of Bmm in vitro. Rather, Puml acted as a phospholipase that localized on lipid droplets, mitochondria, and peroxisomes. Together, these results show that the ABHD4/5 family member Puml is a versatile phospholipase that regulates Drosophila body fat storage and energy metabolism.
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Affiliation(s)
- Philip Hehlert
- Research Group Molecular Physiology Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
| | - Vinzenz Hofferek
- Max-Planck-Institut für Molekulare Pflanzenphysiologie Potsdam, Germany
| | - Christoph Heier
- Institute of Molecular Biosciences University of Graz, Graz, Austria
| | - Thomas O Eichmann
- Institute of Molecular Biosciences University of Graz, Graz, Austria
| | - Dietmar Riedel
- Department of Structural Dynamics, Electron Microscopy, Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
| | - Jonathan Rosenberg
- Research Group Molecular Physiology Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
| | - Anna Takaćs
- Research Group Molecular Physiology Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
| | - Harald M Nagy
- Institute of Molecular Biosciences University of Graz, Graz, Austria
| | - Monika Oberer
- Institute of Molecular Biosciences University of Graz, Graz, Austria.,BioTechMed-Graz Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences University of Graz, Graz, Austria.,BioTechMed-Graz Graz, Austria
| | - Ronald P Kühnlein
- Research Group Molecular Physiology Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany .,Institute of Molecular Biosciences University of Graz, Graz, Austria.,BioTechMed-Graz Graz, Austria
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19
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Huber K, Hofer DC, Trefely S, Pelzmann HJ, Madreiter-Sokolowski C, Duta-Mare M, Schlager S, Trausinger G, Stryeck S, Graier WF, Kolb D, Magnes C, Snyder NW, Prokesch A, Kratky D, Madl T, Wellen KE, Bogner-Strauss JG. N-acetylaspartate pathway is nutrient responsive and coordinates lipid and energy metabolism in brown adipocytes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:337-348. [PMID: 30595160 PMCID: PMC6390944 DOI: 10.1016/j.bbamcr.2018.08.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/27/2018] [Indexed: 12/22/2022]
Abstract
The discovery of significant amounts of metabolically active brown adipose tissue (BAT) in adult humans renders it a promising target for anti-obesity therapies by inducing weight loss through increased energy expenditure. The components of the N-acetylaspartate (NAA) pathway are highly abundant in BAT. Aspartate N-acetyltransferase (Asp-NAT, encoded by Nat8l) synthesizes NAA from acetyl-CoA and aspartate and increases energy expenditure in brown adipocytes. However, the exact mechanism how the NAA pathway contributes to accelerated mobilization and oxidation of lipids and the physiological regulation of the NAA pathway remained elusive. Here, we demonstrate that the expression of NAA pathway genes corresponds to nutrient availability and specifically responds to changes in exogenous glucose. NAA is preferentially produced from glucose-derived acetyl-CoA and aspartate and its concentration increases during adipogenesis. Overexpression of Nat8l drains glucose-derived acetyl-CoA into the NAA pool at the expense of cellular lipids and certain amino acids. Mechanistically, we elucidated that a combined activation of neutral and lysosomal (acid) lipolysis is responsible for the increased lipid degradation. Specifically, translocation of the transcription factor EB to the nucleus activates the biosynthesis of autophagosomes and lysosomes. Lipid degradation within lysosomes accompanied by adipose triglyceride lipase-mediated lipolysis delivers fatty acids for the support of elevated mitochondrial respiration. Together, our data suggest a crucial role of the NAA pathway in energy metabolism and metabolic adaptation in BAT.
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Affiliation(s)
- Katharina Huber
- Institute of Biochemistry, Graz University of Technology, Graz, Austria; Department of Cancer Biology, University of Pennsylvania, Philadelphia, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, USA
| | - Dina C Hofer
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Sophie Trefely
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, USA; AJ Drexel Autism Institute, Drexel University, Philadelphia, USA
| | - Helmut J Pelzmann
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Corina Madreiter-Sokolowski
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Madalina Duta-Mare
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Stefanie Schlager
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Gert Trausinger
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, Graz, Austria
| | - Sarah Stryeck
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Dagmar Kolb
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria
| | - Christoph Magnes
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, Graz, Austria
| | | | - Andreas Prokesch
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Kathryn E Wellen
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, USA
| | - Juliane G Bogner-Strauss
- Institute of Biochemistry, Graz University of Technology, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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20
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Sletten AC, Peterson LR, Schaffer JE. Manifestations and mechanisms of myocardial lipotoxicity in obesity. J Intern Med 2018; 284:478-491. [PMID: 29331057 PMCID: PMC6045461 DOI: 10.1111/joim.12728] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Environmental and socioeconomic changes over the past thirty years have contributed to a dramatic rise in the worldwide prevalence of obesity. Heart disease is amongst the most serious health risks of obesity, with increases in both atherosclerotic coronary heart disease and heart failure among obese individuals. In this review, we focus on primary myocardial alterations in obesity that include hypertrophic remodelling and diastolic dysfunction. Obesity-associated perturbations in myocardial and systemic lipid metabolism are important contributors to cardiovascular complications of obesity. Accumulation of excess lipid in nonadipose cells of the cardiovascular system can cause cell dysfunction and cell death, a process known as lipotoxicity. Lipotoxicity has been modelled in mice using high-fat diet feeding, inbred lines with mutations in leptin receptor signalling, and in genetically engineered mice with enhanced myocardial fatty acid uptake, altered lipid droplet homoeostasis or decreased cardiac fatty acid oxidation. These studies, along with findings in cell culture model systems, indicate that the molecular pathophysiology of lipid overload involves endoplasmic reticulum stress, alterations in autophagy, de novo ceramide synthesis, oxidative stress, inflammation and changes in gene expression. We highlight recent advances that extend our understanding of the impact of obesity and altered lipid metabolism on cardiac function.
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Affiliation(s)
- A C Sletten
- Department of Medicine, Washington University, St Louis, MO, USA
| | - L R Peterson
- Department of Medicine, Washington University, St Louis, MO, USA
| | - J E Schaffer
- Department of Medicine, Washington University, St Louis, MO, USA
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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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Xu S, Zhang X, Liu P. Lipid droplet proteins and metabolic diseases. Biochim Biophys Acta Mol Basis Dis 2018; 1864:1968-1983. [DOI: 10.1016/j.bbadis.2017.07.019] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/14/2017] [Accepted: 07/19/2017] [Indexed: 12/13/2022]
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Adipose tissue ATGL modifies the cardiac lipidome in pressure-overload-induced left ventricular failure. PLoS Genet 2018; 14:e1007171. [PMID: 29320510 PMCID: PMC5779697 DOI: 10.1371/journal.pgen.1007171] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 01/23/2018] [Accepted: 12/25/2017] [Indexed: 01/08/2023] Open
Abstract
Adipose tissue lipolysis occurs during the development of heart failure as a consequence of chronic adrenergic stimulation. However, the impact of enhanced adipose triacylglycerol hydrolysis mediated by adipose triglyceride lipase (ATGL) on cardiac function is unclear. To investigate the role of adipose tissue lipolysis during heart failure, we generated mice with tissue-specific deletion of ATGL (atATGL-KO). atATGL-KO mice were subjected to transverse aortic constriction (TAC) to induce pressure-mediated cardiac failure. The cardiac mouse lipidome and the human plasma lipidome from healthy controls (n = 10) and patients with systolic heart failure (HFrEF, n = 13) were analyzed by MS-based shotgun lipidomics. TAC-induced increases in left ventricular mass (LVM) and diastolic LV inner diameter were significantly attenuated in atATGL-KO mice compared to wild type (wt) -mice. More importantly, atATGL-KO mice were protected against TAC-induced systolic LV failure. Perturbation of lipolysis in the adipose tissue of atATGL-KO mice resulted in the prevention of the major cardiac lipidome changes observed after TAC in wt-mice. Profound changes occurred in the lipid class of phosphatidylethanolamines (PE) in which multiple PE-species were markedly induced in failing wt-hearts, which was attenuated in atATGL-KO hearts. Moreover, selected heart failure-induced PE species in mouse hearts were also induced in plasma samples from patients with chronic heart failure. TAC-induced cardiac PE induction resulted in decreased PC/ PE-species ratios associated with increased apoptotic marker expression in failing wt-hearts, a process absent in atATGL-KO hearts. Perturbation of adipose tissue lipolysis by ATGL-deficiency ameliorated pressure-induced heart failure and the potentially deleterious cardiac lipidome changes that accompany this pathological process, namely the induction of specific PE species. Non-cardiac ATGL-mediated modulation of the cardiac lipidome may play an important role in the pathogenesis of chronic heart failure.
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Rondini EA, Mladenovic-Lucas L, Roush WR, Halvorsen GT, Green AE, Granneman JG. Novel Pharmacological Probes Reveal ABHD5 as a Locus of Lipolysis Control in White and Brown Adipocytes. J Pharmacol Exp Ther 2017; 363:367-376. [PMID: 28928121 PMCID: PMC5698943 DOI: 10.1124/jpet.117.243253] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/09/2017] [Indexed: 12/30/2022] Open
Abstract
Current knowledge regarding acute regulation of adipocyte lipolysis is largely based on receptor-mediated activation or inhibition of pathways that influence intracellular levels of cAMP, thereby affecting protein kinase A (PKA) activity. We recently identified synthetic ligands of α-β-hydrolase domain containing 5 (ABHD5) that directly activate adipose triglyceride lipase (ATGL) by dissociating ABHD5 from its inhibitory regulator, perilipin-1 (PLIN1). In the current study, we used these novel ligands to determine the direct contribution of ABHD5 to various aspects of lipolysis control in white (3T3-L1) and brown adipocytes. ABHD5 ligands stimulated adipocyte lipolysis without affecting PKA-dependent phosphorylation on consensus sites of PLIN1 or hormone-sensitive lipase (HSL). Cotreatment of adipocytes with synthetic ABHD5 ligands did not alter the potency or maximal lipolysis efficacy of the β-adrenergic receptor (ADRB) agonist isoproterenol (ISO), indicating that both target a common pool of ABHD5. Reducing ADRB/PKA signaling with insulin or desensitizing ADRB suppressed lipolysis responses to a subsequent challenge with ISO, but not to ABHD5 ligands. Lastly, despite strong treatment differences in PKA-dependent phosphorylation of HSL, we found that ligand-mediated activation of ABHD5 led to complete triglyceride hydrolysis, which predominantly involved ATGL, but also HSL. These results indicate that the overall pattern of lipolysis controlled by ABHD5 ligands is similar to that of isoproterenol, and that ABHD5 plays a central role in the regulation of adipocyte lipolysis. As lipolysis is critical for adaptive thermogenesis and in catabolic tissue remodeling, ABHD5 ligands may provide a means of activating these processes under conditions where receptor signaling is compromised.
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Affiliation(s)
- Elizabeth A Rondini
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan (E.A.R., L.M.-L., J.G.G.); Department of Chemistry, Scripps Research Institute, Jupiter, Florida (W.R.R., G.T.H.); and Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada (A.E.G.)
| | - Ljiljana Mladenovic-Lucas
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan (E.A.R., L.M.-L., J.G.G.); Department of Chemistry, Scripps Research Institute, Jupiter, Florida (W.R.R., G.T.H.); and Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada (A.E.G.)
| | - William R Roush
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan (E.A.R., L.M.-L., J.G.G.); Department of Chemistry, Scripps Research Institute, Jupiter, Florida (W.R.R., G.T.H.); and Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada (A.E.G.)
| | - Geoff T Halvorsen
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan (E.A.R., L.M.-L., J.G.G.); Department of Chemistry, Scripps Research Institute, Jupiter, Florida (W.R.R., G.T.H.); and Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada (A.E.G.)
| | - Alex E Green
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan (E.A.R., L.M.-L., J.G.G.); Department of Chemistry, Scripps Research Institute, Jupiter, Florida (W.R.R., G.T.H.); and Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada (A.E.G.)
| | - James G Granneman
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan (E.A.R., L.M.-L., J.G.G.); Department of Chemistry, Scripps Research Institute, Jupiter, Florida (W.R.R., G.T.H.); and Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada (A.E.G.)
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25
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Insulin action and resistance in obesity and type 2 diabetes. Nat Med 2017; 23:804-814. [PMID: 28697184 DOI: 10.1038/nm.4350] [Citation(s) in RCA: 775] [Impact Index Per Article: 110.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 05/11/2017] [Indexed: 12/12/2022]
Abstract
Nutritional excess is a major forerunner of type 2 diabetes. It enhances the secretion of insulin, but attenuates insulin's metabolic actions in the liver, skeletal muscle and adipose tissue. However, conflicting evidence indicates a lack of knowledge of the timing of these events during the development of obesity and diabetes, pointing to a key gap in our understanding of metabolic disease. This Perspective reviews alternate viewpoints and recent results on the temporal and mechanistic connections between hyperinsulinemia, obesity and insulin resistance. Although much attention has addressed early steps in the insulin signaling cascade, insulin resistance in obesity seems to be largely elicited downstream of these steps. New findings also connect insulin resistance to extensive metabolic cross-talk between the liver, adipose tissue, pancreas and skeletal muscle. These and other advances over the past 5 years offer exciting opportunities and daunting challenges for the development of new therapeutic strategies for the treatment of type 2 diabetes.
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Zechner R, Madeo F, Kratky D. Cytosolic lipolysis and lipophagy: two sides of the same coin. Nat Rev Mol Cell Biol 2017; 18:671-684. [DOI: 10.1038/nrm.2017.76] [Citation(s) in RCA: 258] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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27
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Critical roles for α/β hydrolase domain 5 (ABHD5)/comparative gene identification-58 (CGI-58) at the lipid droplet interface and beyond. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1233-1241. [PMID: 28827091 DOI: 10.1016/j.bbalip.2017.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 07/24/2017] [Accepted: 07/31/2017] [Indexed: 01/04/2023]
Abstract
Mutations in the gene encoding comparative gene identification 58 (CGI-58), also known as α β hydrolase domain-containing 5 (ABHD5), cause neutral lipid storage disorder with ichthyosis (NLSDI). This inborn error in metabolism is characterized by ectopic accumulation of triacylglycerols (TAG) within cytoplasmic lipid droplets in multiple cell types. Studies over the past decade have clearly demonstrated that CGI-58 is a potent regulator of TAG hydrolysis in the disease-relevant cell types. However, despite the reproducible genetic link between CGI-58 mutations and TAG storage, the molecular mechanisms by which CGI-58 regulates TAG hydrolysis are still incompletely understood. It is clear that CGI-58 can regulate TAG hydrolysis by activating the major TAG hydrolase adipose triglyceride lipase (ATGL), yet CGI-58 can also regulate lipid metabolism via mechanisms that do not involve ATGL. This review highlights recent progress made in defining the physiologic and biochemical function of CGI-58, and its broader role in energy homeostasis. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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28
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Kimmel AR, Sztalryd C. The Perilipins: Major Cytosolic Lipid Droplet-Associated Proteins and Their Roles in Cellular Lipid Storage, Mobilization, and Systemic Homeostasis. Annu Rev Nutr 2017; 36:471-509. [PMID: 27431369 DOI: 10.1146/annurev-nutr-071813-105410] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discovery by Dr. Constantine Londos of perilipin 1, the major scaffold protein at the surface of cytosolic lipid droplets in adipocytes, marked a fundamental conceptual change in the understanding of lipolytic regulation. Focus then shifted from the enzymatic activation of lipases to substrate accessibility, mediated by perilipin-dependent protein sequestration and recruitment. Consequently, the lipid droplet became recognized as a unique, metabolically active cellular organelle and its surface as the active site for novel protein-protein interactions. A new area of investigation emerged, centered on lipid droplets' biology and their role in energy homeostasis. The perilipin family is of ancient origin and has expanded to include five mammalian genes and a growing list of evolutionarily conserved members. Universally, the perilipins modulate cellular lipid storage. This review provides a summary that connects the perilipins to both cellular and whole-body homeostasis.
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Affiliation(s)
- Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, Maryland 20892;
| | - Carole Sztalryd
- The Geriatric Research Education and Clinical Center, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201.,Division of Endocrinology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201;
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29
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Sanders MA, Zhang H, Mladenovic L, Tseng YY, Granneman JG. Molecular Basis of ABHD5 Lipolysis Activation. Sci Rep 2017; 7:42589. [PMID: 28211464 PMCID: PMC5314347 DOI: 10.1038/srep42589] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/11/2017] [Indexed: 12/21/2022] Open
Abstract
Alpha-beta hydrolase domain-containing 5 (ABHD5), the defective gene in human Chanarin-Dorfman syndrome, is a highly conserved regulator of adipose triglyceride lipase (ATGL)-mediated lipolysis that plays important roles in metabolism, tumor progression, viral replication, and skin barrier formation. The structural determinants of ABHD5 lipolysis activation, however, are unknown. We performed comparative evolutionary analysis and structural modeling of ABHD5 and ABHD4, a functionally distinct paralog that diverged from ABHD5 ~500 million years ago, to identify determinants of ABHD5 lipolysis activation. Two highly conserved ABHD5 amino acids (R299 and G328) enabled ABHD4 (ABHD4 N303R/S332G) to activate ATGL in Cos7 cells, brown adipocytes, and artificial lipid droplets. The corresponding ABHD5 mutations (ABHD5 R299N and ABHD5 G328S) selectively disrupted lipolysis without affecting ATGL lipid droplet translocation or ABHD5 interactions with perilipin proteins and ABHD5 ligands, demonstrating that ABHD5 lipase activation could be dissociated from its other functions. Structural modeling placed ABHD5 R299/G328 and R303/G332 from gain-of-function ABHD4 in close proximity on the ABHD protein surface, indicating they form part of a novel functional surface required for lipase activation. These data demonstrate distinct ABHD5 functional properties and provide new insights into the functional evolution of ABHD family members and the structural basis of lipase regulation.
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Affiliation(s)
- Matthew A. Sanders
- Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Huamei Zhang
- Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Ljiljana Mladenovic
- Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Yan Yuan Tseng
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - James G. Granneman
- Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
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30
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Grond S, Radner FPW, Eichmann TO, Kolb D, Grabner GF, Wolinski H, Gruber R, Hofer P, Heier C, Schauer S, Rülicke T, Hoefler G, Schmuth M, Elias PM, Lass A, Zechner R, Haemmerle G. Skin Barrier Development Depends on CGI-58 Protein Expression during Late-Stage Keratinocyte Differentiation. J Invest Dermatol 2016; 137:403-413. [PMID: 27725204 PMCID: PMC5551682 DOI: 10.1016/j.jid.2016.09.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 08/02/2016] [Accepted: 09/27/2016] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) and its coactivator comparative gene identification-58 (CGI-58) are limiting in cellular triglyceride catabolism. Although ATGL deficiency is compatible with normal skin development, mice globally lacking CGI-58 die postnatally and exhibit a severe epidermal permeability barrier defect, which may originate from epidermal and/or peripheral changes in lipid and energy metabolism. Here, we show that epidermis-specific disruption of CGI-58 is sufficient to provoke a defect in the formation of a functional corneocyte lipid envelope linked to impaired ω-O-acylceramide synthesis. As a result, epidermis-specific CGI-58-deficient mice show severe skin dysfunction, arguing for a tissue autonomous cause of disease development. Defective skin permeability barrier formation in global CGI-58-deficient mice could be reversed via transgenic restoration of CGI-58 expression in differentiated but not basal keratinocytes suggesting that CGI-58 is essential for lipid metabolism in suprabasal epidermal layers. The compatibility of ATGL deficiency with normal epidermal function indicated that CGI-58 may stimulate an epidermal triglyceride lipase beyond ATGL required for the adequate provision of fatty acids as a substrate for ω-O-acylceramide synthesis. Pharmacological inhibition of ATGL enzyme activity similarly reduced triglyceride-hydrolytic activities in wild-type and CGI-58 overexpressing epidermis implicating that CGI-58 participates in ω-O-acylceramide biogenesis independent of its role as a coactivator of epidermal triglyceride catabolism.
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Affiliation(s)
- Susanne Grond
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Franz P W Radner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Thomas O Eichmann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Dagmar Kolb
- Center for Medical Research/Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria
| | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed-Graz, Microscopy Facility, University of Graz, Graz, Austria
| | - Robert Gruber
- Department of Dermatology, Venereology and Allergology, University of Innsbruck, Innsbruck, Austria
| | - Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Silvia Schauer
- Institute of Pathology, Medical University of Graz, Graz, Austria; Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Thomas Rülicke
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Gerald Hoefler
- BioTechMed-Graz, Microscopy Facility, University of Graz, Graz, Austria; Institute of Pathology, Medical University of Graz, Graz, Austria; Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Matthias Schmuth
- Department of Dermatology, Venereology and Allergology, University of Innsbruck, Innsbruck, Austria
| | - Peter M Elias
- Department of Dermatology, University of California San Francisco, San Francisco, California, USA
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
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31
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Zlobine I, Gopal K, Ussher JR. Lipotoxicity in obesity and diabetes-related cardiac dysfunction. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1555-68. [DOI: 10.1016/j.bbalip.2016.02.011] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 02/15/2016] [Indexed: 12/11/2022]
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32
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Lord CC, Ferguson D, Thomas G, Brown AL, Schugar RC, Burrows A, Gromovsky AD, Betters J, Neumann C, Sacks J, Marshall S, Watts R, Schweiger M, Lee RG, Crooke RM, Graham MJ, Lathia JD, Sakaguchi TF, Lehner R, Haemmerle G, Zechner R, Brown JM. Regulation of Hepatic Triacylglycerol Metabolism by CGI-58 Does Not Require ATGL Co-activation. Cell Rep 2016; 16:939-949. [PMID: 27396333 DOI: 10.1016/j.celrep.2016.06.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/20/2016] [Accepted: 06/10/2016] [Indexed: 01/23/2023] Open
Abstract
Adipose triglyceride lipase (ATGL) and comparative gene identification 58 (CGI-58) are critical regulators of triacylglycerol (TAG) turnover. CGI-58 is thought to regulate TAG mobilization by stimulating the enzymatic activity of ATGL. However, it is not known whether this coactivation function of CGI-58 occurs in vivo. Moreover, the phenotype of human CGI-58 mutations suggests ATGL-independent functions. Through direct comparison of mice with single or double deficiency of CGI-58 and ATGL, we show here that CGI-58 knockdown causes hepatic steatosis in both the presence and absence of ATGL. CGI-58 also regulates hepatic diacylglycerol (DAG) and inflammation in an ATGL-independent manner. Interestingly, ATGL deficiency, but not CGI-58 deficiency, results in suppression of the hepatic and adipose de novo lipogenic program. Collectively, these findings show that CGI-58 regulates hepatic neutral lipid storage and inflammation in the genetic absence of ATGL, demonstrating that mechanisms driving TAG lipolysis in hepatocytes differ significantly from those in adipocytes.
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Affiliation(s)
- Caleb C Lord
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9077, USA
| | - Daniel Ferguson
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Gwynneth Thomas
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA
| | - Amanda L Brown
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Rebecca C Schugar
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Amy Burrows
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Anthony D Gromovsky
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Jenna Betters
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA
| | - Chase Neumann
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Jessica Sacks
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Stephanie Marshall
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Russell Watts
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Richard G Lee
- Cardiovascular Group, Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Rosanne M Crooke
- Cardiovascular Group, Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Mark J Graham
- Cardiovascular Group, Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Justin D Lathia
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Takuya F Sakaguchi
- Department of Stem Cell Biology and Regenerative Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Richard Lehner
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA.
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33
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Carley AN, Lewandowski ED. Triacylglycerol turnover in the failing heart. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1492-9. [PMID: 26993578 DOI: 10.1016/j.bbalip.2016.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 12/20/2022]
Abstract
No longer regarded as physiologically inert the endogenous triacylglyceride (TAG) pool within the cardiomyocyte is now recognized to play a dynamic role in metabolic regulation. Beyond static measures of content, the relative rates of interconversion among acyl intermediates are more closely linked to dynamic processes of physiological function in normal and diseased hearts, with the potential for both adaptive and maladaptive contributions. Indeed, multiple inefficiencies in cardiac metabolism have been identified in the decompensated, hypertrophied and failing heart. Among the intracellular responses to physiological, metabolic and pathological stresses, TAG plays a central role in the balance of lipid handling and signaling mechanisms. TAG dynamics are profoundly altered from normal in both diabetic and pathologically stressed hearts. More than just expansion or contraction of the stored lipid pool, the turnover rates of TAG are sensitive to and compete against other enzymatic pathways, anabolic and catabolic, for reactive acyl-CoA units. The rates of TAG synthesis and lipolysis thusly affect multiple components of cardiomyocyte function, including energy metabolism, cell signaling, and enzyme activation, as well as the regulation of gene expression in both normal and diseased states. This review examines the multiple etiologies and metabolic consequences of the failing heart and the central role of lipid storage dynamics in the pathogenic process. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.
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Affiliation(s)
- Andrew N Carley
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, United States
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34
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Dolinsky VW, Cole LK, Sparagna GC, Hatch GM. Cardiac mitochondrial energy metabolism in heart failure: Role of cardiolipin and sirtuins. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1544-54. [PMID: 26972373 DOI: 10.1016/j.bbalip.2016.03.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 01/19/2023]
Abstract
Mitochondrial oxidation of fatty acids accounts for the majority of cardiac ATP production in the heart. Fatty acid utilization by cardiac mitochondria is controlled at the level of fatty acid uptake, lipid synthesis, mobilization and mitochondrial import and oxidation. Consequently defective mitochondrial function appears to be central to the development of heart failure. Cardiolipin is a key mitochondrial phospholipid required for the activity of the electron transport chain. In heart failure, loss of cardiolipin and tetralinoleoylcardiolipin helps to fuel the generation of excessive reactive oxygen species that are a by-product of inefficient mitochondrial electron transport chain complexes I and III. In this vicious cycle, reactive oxygen species generate lipid peroxides and may, in turn, cause oxidation of cardiolipin catalyzed by cytochrome c leading to cardiomyocyte apoptosis. Hence, preservation of cardiolipin and mitochondrial function may be keys to the prevention of heart failure development. In this review, we summarize cardiac energy metabolism and the important role that fatty acid uptake and metabolism play in this process and how defects in these result in heart failure. We highlight the key role that cardiolipin and sirtuins play in cardiac mitochondrial β-oxidation. In addition, we review the potential of pharmacological modulation of cardiolipin through the polyphenolic molecule resveratrol as a sirtuin-activator in attenuating mitochondrial dysfunction. Finally, we provide novel experimental evidence that resveratrol treatment increases cardiolipin in isolated H9c2 cardiac myocytes and tetralinoleoylcardiolipin in the heart of the spontaneously hypertensive rat and hypothesize that this leads to improvement in mitochondrial function. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.
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Affiliation(s)
- Vernon W Dolinsky
- Department of Pharmacology & Therapeutics, Faculty of Health Sciences, University of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Children's Hospital Research Institute of Manitoba (CHRIM), Canada
| | - Laura K Cole
- Department of Pharmacology & Therapeutics, Faculty of Health Sciences, University of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Children's Hospital Research Institute of Manitoba (CHRIM), Canada
| | - Genevieve C Sparagna
- Department of Medicine, Division of Cardiology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Grant M Hatch
- Department of Pharmacology & Therapeutics, Faculty of Health Sciences, University of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Children's Hospital Research Institute of Manitoba (CHRIM), Canada; Department of Biochemistry and Medical Genetics, Faculty of Health Sciences, Center for Research and Treatment of Atherosclerosis, University of Manitoba, Winnipeg, Manitoba, Canada.
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Lipid metabolism and signaling in cardiac lipotoxicity. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1513-24. [PMID: 26924249 DOI: 10.1016/j.bbalip.2016.02.016] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 02/19/2016] [Accepted: 02/19/2016] [Indexed: 01/01/2023]
Abstract
The heart balances uptake, metabolism and oxidation of fatty acids (FAs) to maintain ATP production, membrane biosynthesis and lipid signaling. Under conditions where FA uptake outpaces FA oxidation and FA sequestration as triacylglycerols in lipid droplets, toxic FA metabolites such as ceramides, diacylglycerols, long-chain acyl-CoAs, and acylcarnitines can accumulate in cardiomyocytes and cause cardiomyopathy. Moreover, studies using mutant mice have shown that dysregulation of enzymes involved in triacylglycerol, phospholipid, and sphingolipid metabolism in the heart can lead to the excess deposition of toxic lipid species that adversely affect cardiomyocyte function. This review summarizes our current understanding of lipid uptake, metabolism and signaling pathways that have been implicated in the development of lipotoxic cardiomyopathy under conditions including obesity, diabetes, aging, and myocardial ischemia-reperfusion. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.
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Heier C, Haemmerle G. Fat in the heart: The enzymatic machinery regulating cardiac triacylglycerol metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1500-12. [PMID: 26924251 DOI: 10.1016/j.bbalip.2016.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 01/22/2023]
Abstract
The heart predominantly utilizes fatty acids (FAs) as energy substrate. FAs that enter cardiomyocytes can be activated and directly oxidized within mitochondria (and peroxisomes) or they can be esterified and intracellularly deposited as triacylglycerol (TAG) often simply referred to as fat. An increase in cardiac TAG can be a signature of the diseased heart and may implicate a minor role of TAG synthesis and breakdown in normal cardiac energy metabolism. Often overlooked, the heart has an extremely high TAG turnover and the transient deposition of FAs within the cardiac TAG pool critically determines the availability of FAs as energy substrate and signaling molecules. We herein review the recent literature regarding the enzymes and co-regulators involved in cardiomyocyte TAG synthesis and catabolism and discuss the interconnection of these metabolic pathways in the normal and diseased heart. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.
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Affiliation(s)
- Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Austria
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Ruiz M, Coderre L, Lachance D, Houde V, Martel C, Thompson Legault J, Gillis MA, Bouchard B, Daneault C, Carpentier AC, Gaestel M, Allen BG, Des Rosiers C. MK2 Deletion in Mice Prevents Diabetes-Induced Perturbations in Lipid Metabolism and Cardiac Dysfunction. Diabetes 2016; 65:381-92. [PMID: 26558681 DOI: 10.2337/db15-0238] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 11/05/2015] [Indexed: 11/13/2022]
Abstract
Heart disease remains a major complication of diabetes, and the identification of new therapeutic targets is essential. This study investigates the role of the protein kinase MK2, a p38 mitogen-activated protein kinase downstream target, in the development of diabetes-induced cardiomyopathy. Diabetes was induced in control (MK2(+/+)) and MK2-null (MK2(-/-)) mice using repeated injections of a low dose of streptozotocin (STZ). This protocol generated in MK2(+/+) mice a model of diabetes characterized by a 50% decrease in plasma insulin, hyperglycemia, and insulin resistance (IR), as well as major contractile dysfunction, which was associated with alterations in proteins involved in calcium handling. While MK2(-/-)-STZ mice remained hyperglycemic, they showed improved IR and none of the cardiac functional or molecular alterations. Further analyses highlighted marked lipid perturbations in MK2(+/+)-STZ mice, which encompass increased 1) circulating levels of free fatty acid, ketone bodies, and long-chain acylcarnitines and 2) cardiac triglyceride accumulation and ex vivo palmitate β-oxidation. MK2(-/-)-STZ mice were also protected against all these diabetes-induced lipid alterations. Our results demonstrate the benefits of MK2 deletion on diabetes-induced cardiac molecular and lipid metabolic changes, as well as contractile dysfunction. As a result, MK2 represents a new potential therapeutic target to prevent diabetes-induced cardiac dysfunction.
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Affiliation(s)
- Matthieu Ruiz
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada
| | - Lise Coderre
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Dominic Lachance
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada
| | - Valérie Houde
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada
| | - Cécile Martel
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada
| | - Julie Thompson Legault
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada
| | | | - Bertrand Bouchard
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada
| | - Caroline Daneault
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada
| | - André C Carpentier
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Matthias Gaestel
- Institute of Biochemistry, Hannover Medical School, Hannover, Germany
| | - Bruce G Allen
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada Department of Medicine, Université de Montréal, Montréal, Québec, Canada Department of Biochemistry, Université de Montréal, Montréal, Québec, Canada
| | - Christine Des Rosiers
- Department of Nutrition, Université de Montréal, Montréal, Québec, Canada Research Center, Montreal Heart Institute, Montréal, Québec, Canada Department of Medicine, Université de Montréal, Montréal, Québec, Canada
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Khatib A, Arhab Y, Bentebibel A, Abousalham A, Noiriel A. Reassessing the Potential Activities of Plant CGI-58 Protein. PLoS One 2016; 11:e0145806. [PMID: 26745266 PMCID: PMC4706320 DOI: 10.1371/journal.pone.0145806] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 12/09/2015] [Indexed: 11/23/2022] Open
Abstract
Comparative Gene Identification-58 (CGI-58) is a widespread protein found in animals and plants. This protein has been shown to participate in lipolysis in mice and humans by activating Adipose triglyceride lipase (ATGL), the initial enzyme responsible for the triacylglycerol (TAG) catabolism cascade. Human mutation of CGI-58 is the cause of Chanarin-Dorfman syndrome, an orphan disease characterized by a systemic accumulation of TAG which engenders tissue disorders. The CGI-58 protein has also been shown to participate in neutral lipid metabolism in plants and, in this case, a mutation again provokes TAG accumulation. Although its roles as an ATGL coactivator and in lipid metabolism are quite clear, the catalytic activity of CGI-58 is still in question. The acyltransferase activities of CGI-58 have been speculated about, reported or even dismissed and experimental evidence that CGI-58 expressed in E. coli possesses an unambiguous catalytic activity is still lacking. To address this problem, we developed a new set of plasmids and site-directed mutants to elucidate the in vivo effects of CGI-58 expression on lipid metabolism in E. coli. By analyzing the lipid composition in selected E. coli strains expressing CGI-58 proteins, and by reinvestigating enzymatic tests with adequate controls, we show here that recombinant plant CGI-58 has none of the proposed activities previously described. Recombinant plant and mouse CGI-58 both lack acyltransferase activity towards either lysophosphatidylglycerol or lysophosphatidic acid to form phosphatidylglycerol or phosphatidic acid and recombinant plant CGI-58 does not catalyze TAG or phospholipid hydrolysis. However, expression of recombinant plant CGI-58, but not mouse CGI-58, led to a decrease in phosphatidylglycerol in all strains of E. coli tested, and a mutation of the putative catalytic residues restored a wild-type phenotype. The potential activities of plant CGI-58 are subsequently discussed.
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Affiliation(s)
- Abdallah Khatib
- Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires UMR 5246 CNRS, Organisation et Dynamique des Membranes Biologiques, Université Lyon 1, Villeurbanne, France
| | - Yani Arhab
- Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires UMR 5246 CNRS, Organisation et Dynamique des Membranes Biologiques, Université Lyon 1, Villeurbanne, France
| | - Assia Bentebibel
- Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires UMR 5246 CNRS, Organisation et Dynamique des Membranes Biologiques, Université Lyon 1, Villeurbanne, France
| | - Abdelkarim Abousalham
- Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires UMR 5246 CNRS, Organisation et Dynamique des Membranes Biologiques, Université Lyon 1, Villeurbanne, France
| | - Alexandre Noiriel
- Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires UMR 5246 CNRS, Organisation et Dynamique des Membranes Biologiques, Université Lyon 1, Villeurbanne, France
- * E-mail:
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Effect of Bariatric Weight Loss on the Adipose Lipolytic Transcriptome in Obese Humans. Mediators Inflamm 2015; 2015:106237. [PMID: 26663986 PMCID: PMC4667060 DOI: 10.1155/2015/106237] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/02/2015] [Indexed: 01/04/2023] Open
Abstract
Background. Dysregulated lipolysis has been implicated in mechanisms of cardiometabolic disease and inflammation in obesity. Purpose. We sought to examine the effect of bariatric weight loss on adipose tissue lipolytic gene expression and their relationship to systemic metabolic parameters in obese subjects. Methods/Results. We biopsied subcutaneous adipose tissue in 19 obese individuals (BMI 42 ± 5 kg/m2, 79% female) at baseline and after a mean period of 8 ± 5 months (range 3–15 months) following bariatric surgery. We performed adipose tissue mRNA expression of proteins involved in triglyceride hydrolysis and correlated their weight loss induced alterations with systemic parameters associated with cardiovascular disease risk. mRNA transcripts of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), and lipid droplet proteins comparative gene identification 58 (CGI-58) and perilipin increased significantly after weight loss (p < 0.05 for all). ATGL expression correlated inversely with plasma triglyceride (TG), hemoglobin A1C (HbA1C), and glucose, and HSL expression correlated negatively with glucose, while CGI-58 was inversely associated with HbA1C. Conclusion. We observed increased expression of adipose tissue lipolytic genes following bariatric weight loss which correlated inversely with systemic markers of lipid and glucose metabolism. Functional alterations in lipolysis in human adipose tissue may play a role in shaping cardiometabolic phenotypes in human obesity.
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Osumi T, Kuramoto K. Heart lipid droplets and lipid droplet-binding proteins: Biochemistry, physiology, and pathology. Exp Cell Res 2015; 340:198-204. [PMID: 26524506 DOI: 10.1016/j.yexcr.2015.10.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/29/2015] [Accepted: 10/29/2015] [Indexed: 10/22/2022]
Affiliation(s)
- Takashi Osumi
- Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan.
| | - Kenta Kuramoto
- Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan
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41
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Heier C, Radner FPW, Moustafa T, Schreiber R, Grond S, Eichmann TO, Schweiger M, Schmidt A, Cerk IK, Oberer M, Theussl HC, Wojciechowski J, Penninger JM, Zimmermann R, Zechner R. G0/G1 Switch Gene 2 Regulates Cardiac Lipolysis. J Biol Chem 2015; 290:26141-50. [PMID: 26350455 DOI: 10.1074/jbc.m115.671842] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Indexed: 12/13/2022] Open
Abstract
The anabolism and catabolism of myocardial triacylglycerol (TAG) stores are important processes for normal cardiac function. TAG synthesis detoxifies and stockpiles fatty acids to prevent lipotoxicity, whereas TAG hydrolysis (lipolysis) remobilizes fatty acids from endogenous storage pools as energy substrates, signaling molecules, or precursors for complex lipids. This study focused on the role of G0/G1 switch 2 (G0S2) protein, which was previously shown to inhibit the principal TAG hydrolase adipose triglyceride lipase (ATGL), in the regulation of cardiac lipolysis. Using wild-type and mutant mice, we show the following: (i) G0S2 is expressed in the heart and regulated by the nutritional status with highest expression levels after re-feeding. (ii) Cardiac-specific overexpression of G0S2 inhibits cardiac lipolysis by direct protein-protein interaction with ATGL. This leads to severe cardiac steatosis. The steatotic hearts caused by G0S2 overexpression are less prone to fibrotic remodeling or cardiac dysfunction than hearts with a lipolytic defect due to ATGL deficiency. (iii) Conversely to the phenotype of transgenic mice, G0S2 deficiency results in a de-repression of cardiac lipolysis and decreased cardiac TAG content. We conclude that G0S2 acts as a potent ATGL inhibitor in the heart modulating cardiac substrate utilization by regulating cardiac lipolysis.
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Affiliation(s)
- Christoph Heier
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Franz P W Radner
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Tarek Moustafa
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria, the Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine and
| | - Renate Schreiber
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Susanne Grond
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Thomas O Eichmann
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Martina Schweiger
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Albrecht Schmidt
- Division of Cardiology, Department of Internal Medicine, Medical University of Graz, A-8036 Graz, Austria, and
| | - Ines K Cerk
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Monika Oberer
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - H-Christian Theussl
- the Transgenic Service, Research Institute of Molecular Pathology (IMP), 1030 Vienna, Austria, and the IMBA Institute of Molecular Biotechnology of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Jacek Wojciechowski
- the Transgenic Service, Research Institute of Molecular Pathology (IMP), 1030 Vienna, Austria, and the IMBA Institute of Molecular Biotechnology of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Josef M Penninger
- the Transgenic Service, Research Institute of Molecular Pathology (IMP), 1030 Vienna, Austria, and the IMBA Institute of Molecular Biotechnology of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Robert Zimmermann
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Rudolf Zechner
- From the Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria,
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Foryst-Ludwig A, Kreissl MC, Benz V, Brix S, Smeir E, Ban Z, Januszewicz E, Salatzki J, Grune J, Schwanstecher AK, Blumrich A, Schirbel A, Klopfleisch R, Rothe M, Blume K, Halle M, Wolfarth B, Kershaw EE, Kintscher U. Adipose Tissue Lipolysis Promotes Exercise-induced Cardiac Hypertrophy Involving the Lipokine C16:1n7-Palmitoleate. J Biol Chem 2015; 290:23603-15. [PMID: 26260790 DOI: 10.1074/jbc.m115.645341] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Indexed: 12/28/2022] Open
Abstract
Endurance exercise training induces substantial adaptive cardiac modifications such as left ventricular hypertrophy (LVH). Simultaneously to the development of LVH, adipose tissue (AT) lipolysis becomes elevated upon endurance training to cope with enhanced energy demands. In this study, we investigated the impact of adipose tissue lipolysis on the development of exercise-induced cardiac hypertrophy. Mice deficient for adipose triglyceride lipase (Atgl) in AT (atATGL-KO) were challenged with chronic treadmill running. Exercise-induced AT lipolytic activity was significantly reduced in atATGL-KO mice accompanied by the absence of a plasma fatty acid (FA) increase. These processes were directly associated with a prominent attenuation of myocardial FA uptake in atATGL-KO and a significant reduction of the cardiac hypertrophic response to exercise. FA serum profiling revealed palmitoleic acid (C16:1n7) as a new molecular co-mediator of exercise-induced cardiac hypertrophy by inducing nonproliferative cardiomyocyte growth. In parallel, serum FA analysis and echocardiography were performed in 25 endurance athletes. In consonance, the serum C16:1n7 palmitoleate level exhibited a significantly positive correlation with diastolic interventricular septum thickness in those athletes. No correlation existed between linoleic acid (18:2n6) and diastolic interventricular septum thickness. Collectively, our data provide the first evidence that adipose tissue lipolysis directly promotes the development of exercise-induced cardiac hypertrophy involving the lipokine C16:1n7 palmitoleate as a molecular co-mediator. The identification of a lipokine involved in physiological cardiac growth may help to develop future lipid-based therapies for pathological LVH or heart failure.
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Affiliation(s)
- Anna Foryst-Ludwig
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany, the DZHK (German Center for Cardiovascular Research), 10115 Berlin, Germany
| | - Michael C Kreissl
- the Department of Nuclear Medicine, University Hospital Wuerzburg, 97080 Wuerzburg, Germany
| | - Verena Benz
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Sarah Brix
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Elia Smeir
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Zsofia Ban
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Elżbieta Januszewicz
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Janek Salatzki
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Jana Grune
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Anne-Kathrin Schwanstecher
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Annelie Blumrich
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Andreas Schirbel
- the Department of Nuclear Medicine, University Hospital Wuerzburg, 97080 Wuerzburg, Germany
| | - Robert Klopfleisch
- the Department of Veterinary Pathology, College of Veterinary Medicine, Freie Universität Berlin, 14163 Berlin, Germany
| | | | - Katharina Blume
- the Department of Prevention, Rehabilitation, and Sports Medicine, Technische Universitaet Muenchen, 80809 Muenchen, Germany
| | - Martin Halle
- the Department of Prevention, Rehabilitation, and Sports Medicine, Technische Universitaet Muenchen, 80809 Muenchen, Germany, the DZHK (German Center for Cardiovascular Research), Munich Heart Alliance, 80809 Munich, Germany
| | - Bernd Wolfarth
- the Department of Sports Medicine, Humboldt University/Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Erin E Kershaw
- the Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, and
| | - Ulrich Kintscher
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany, the DZHK (German Center for Cardiovascular Research), 10115 Berlin, Germany
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43
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Jaeger D, Schoiswohl G, Hofer P, Schreiber R, Schweiger M, Eichmann TO, Pollak NM, Poecher N, Grabner GF, Zierler KA, Eder S, Kolb D, Radner FPW, Preiss-Landl K, Lass A, Zechner R, Kershaw EE, Haemmerle G. Fasting-induced G0/G1 switch gene 2 and FGF21 expression in the liver are under regulation of adipose tissue derived fatty acids. J Hepatol 2015; 63:437-45. [PMID: 25733154 PMCID: PMC4518503 DOI: 10.1016/j.jhep.2015.02.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 02/18/2015] [Accepted: 02/20/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Adipose tissue (AT)-derived fatty acids (FAs) are utilized for hepatic triacylglycerol (TG) generation upon fasting. However, their potential impact as signaling molecules is not established. Herein we examined the role of exogenous AT-derived FAs in the regulation of hepatic gene expression by investigating mice with a defect in AT-derived FA supply to the liver. METHODS Plasma FA levels, tissue TG hydrolytic activities and lipid content were determined in mice lacking the lipase co-activator comparative gene identification-58 (CGI-58) selectively in AT (CGI-58-ATko) applying standard protocols. Hepatic expression of lipases, FA oxidative genes, transcription factors, ER stress markers, hormones and cytokines were determined by qRT-PCR, Western blotting and ELISA. RESULTS Impaired AT-derived FA supply upon fasting of CGI-58-ATko mice causes a marked defect in liver PPARα-signaling and nuclear CREBH translocation. This severely reduced the expression of respective target genes such as the ATGL inhibitor G0/G1 switch gene-2 (G0S2) and the endocrine metabolic regulator FGF21. These changes could be reversed by lipid administration and raising plasma FA levels. Impaired AT-lipolysis failed to induce hepatic G0S2 expression in fasted CGI-58-ATko mice leading to enhanced ATGL-mediated TG-breakdown strongly reducing hepatic TG deposition. On high fat diet, impaired AT-lipolysis counteracts hepatic TG accumulation and liver stress linked to improved systemic insulin sensitivity. CONCLUSIONS AT-derived FAs are a critical regulator of hepatic fasting gene expression required for the induction of G0S2-expression in the liver to control hepatic TG-breakdown. Interfering with AT-lipolysis or hepatic G0S2 expression represents an effective strategy for the treatment of hepatic steatosis.
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Affiliation(s)
- Doris Jaeger
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Gabriele Schoiswohl
- Division of Endocrinology, Diabetes, and Metabolism, University of Pittsburgh, PA 15261, USA
| | - Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Thomas O Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Nina M Pollak
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Nadja Poecher
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Kathrin A Zierler
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Sandra Eder
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Dagmar Kolb
- ZMF, Center for Medical Research, Medical University of Graz, A-8010 Graz, Austria
| | - Franz P W Radner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Karina Preiss-Landl
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria
| | - Erin E Kershaw
- Division of Endocrinology, Diabetes, and Metabolism, University of Pittsburgh, PA 15261, USA
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria.
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44
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Xie P, Kadegowda AKG, Ma Y, Guo F, Han X, Wang M, Groban L, Xue B, Shi H, Li H, Yu L. Muscle-specific deletion of comparative gene identification-58 (CGI-58) causes muscle steatosis but improves insulin sensitivity in male mice. Endocrinology 2015; 156:1648-58. [PMID: 25751639 PMCID: PMC4398773 DOI: 10.1210/en.2014-1892] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Intramyocellular accumulation of lipids is often associated with insulin resistance. Deficiency of comparative gene identification-58 (CGI-58) causes cytosolic deposition of triglyceride (TG)-rich lipid droplets in most cell types, including muscle due to defective TG hydrolysis. It was unclear, however, whether CGI-58 deficiency-induced lipid accumulation in muscle influences insulin sensitivity. Here we show that muscle-specific CGI-58 knockout mice relative to their controls have increased glucose tolerance and insulin sensitivity on a Western-type high-fat diet, despite TG accumulation in both heart and oxidative skeletal muscle and cholesterol deposition in heart. Although the intracardiomyocellular lipid deposition results in cardiac ventricular fibrosis and systolic dysfunction, muscle-specific CGI-58 knockout mice show increased glucose uptake in heart and soleus muscle, improved insulin signaling in insulin-sensitive tissues, and reduced plasma concentrations of glucose, insulin, and cholesterol. Hepatic contents of TG and cholesterol are also decreased in these animals. Cardiac steatosis is attributable, at least in part, to decreases in cardiac TG hydrolase activity and peroxisome proliferator-activated receptor-α/peroxisome proliferator-activated receptor-γ coactivator-1-dependent mitochondrial fatty acid oxidation. In conclusion, muscle CGI-58 deficiency causes cardiac dysfunction and fat deposition in oxidative muscles but induces a series of favorable metabolic changes in mice fed a high-fat diet.
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Affiliation(s)
- Ping Xie
- Departments of Biochemistry (P.X., Y.M., F.G., L.Y.) and Anesthesiology (L.G.), Wake Forest School of Medicine, Winston-Salem, North Carolina 27157; Department of Animal and Avian Sciences (A.K.G.G., Y.M., L.Y.), University of Maryland, College Park, Maryland 20742; Diabetes and Obesity Research Center (X.H., M.W.), Sanford-Burnham Medical Research Institute, Orlando, Florida 32827; Department of Biology (B.X., H.S.), Georgia State University, Atlanta, Georgia 30303; and The Key Laboratory of Remodeling-Related Cardiovascular Diseases (H.L.), Capital Medical University, Ministry of Education, Beijing Institute of Heart, Lung, and Blood Vessel Diseases, Beijing Anzhen Hospital Affiliated the Capital Medical University, Beijing 100029, People's Republic of China
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45
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Pollak NM, Jaeger D, Kolleritsch S, Zimmermann R, Zechner R, Lass A, Haemmerle G. The interplay of protein kinase A and perilipin 5 regulates cardiac lipolysis. J Biol Chem 2015; 290:1295-306. [PMID: 25418045 PMCID: PMC4340377 DOI: 10.1074/jbc.m114.604744] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 11/21/2014] [Indexed: 12/21/2022] Open
Abstract
Defective lipolysis in mice lacking adipose triglyceride lipase provokes severe cardiac steatosis and heart dysfunction, markedly shortening life span. Similarly, cardiac muscle (CM)-specific Plin5 overexpression (CM-Plin5) leads to severe triglyceride (TG) accumulation in cardiomyocytes via impairing TG breakdown. Interestingly, cardiac steatosis due to overexpression of Plin5 is compatible with normal heart function and life span indicating a more moderate impact of Plin5 overexpression on cardiac lipolysis and energy metabolism. We hypothesized that cardiac Plin5 overexpression does not constantly impair cardiac lipolysis. In line with this assumption, TG levels decreased in CM of fasted compared with nonfasted CM-Plin5 mice indicating that fasting may lead to a diminished barrier function of Plin5. Recent studies demonstrated that Plin5 is phosphorylated, and activation of adenylyl cyclase leads to phosphorylation of Plin5, suggesting that Plin5 is a substrate for PKA. Furthermore, any significance of Plin5 phosphorylation by PKA in the regulation of TG mobilization from lipid droplets (LDs) is unknown. Here, we show that the lipolytic barrier of Plin5-enriched LDs, either prepared from cardiac tissue of CM-Plin5 mice or Plin5-transfected cells, is abrogated by incubation with PKA. Notably, PKA-induced lipolysis of LDs enriched with Plin5 carrying a single mutation at serine 155 (PlinS155A) of the putative PKA phosphorylation site was substantially impaired revealing a critical role for PKA in Plin5-regulated lipolysis. The strong increase in protein levels of phosphorylated PKA in CM of Plin5 transgenic mice may partially restore fatty acid release from Plin5-enriched LDs, rendering these hearts compatible with normal heart function despite massive steatosis.
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Affiliation(s)
- Nina M Pollak
- From the Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Doris Jaeger
- From the Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | | | - Robert Zimmermann
- From the Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- From the Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Achim Lass
- From the Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Guenter Haemmerle
- From the Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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46
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Deficiency of a lipid droplet protein, perilipin 5, suppresses myocardial lipid accumulation, thereby preventing type 1 diabetes-induced heart malfunction. Mol Cell Biol 2014; 34:2721-31. [PMID: 24820416 DOI: 10.1128/mcb.00133-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lipid droplet (LD) is a ubiquitous organelle that stores triacylglycerol and other neutral lipids. Perilipin 5 (Plin5), a member of the perilipin protein family that is abundantly expressed in the heart, is essential to protect LDs from attack by lipases, including adipose triglyceride lipase. Plin5 controls heart metabolism and performance by maintaining LDs under physiological conditions. Aberrant lipid accumulation in the heart leads to organ malfunction, or cardiomyopathy. To elucidate the role of Plin5 in a metabolically disordered state and the mechanism of lipid-induced cardiomyopathy, we studied the effects of streptozotocin-induced type 1 diabetes in Plin5-knockout (KO) mice. In contrast to diabetic wild-type mice, diabetic Plin5-KO mice lacked detectable LDs in the heart and did not exhibit aberrant lipid accumulation, excessive reactive oxygen species (ROS) generation, or heart malfunction. Moreover, diabetic Plin5-KO mice exhibited lower heart levels of lipotoxic molecules, such as diacylglycerol and ceramide, than wild-type mice. Membrane translocation of protein kinase C and the assembly of NADPH oxidase 2 complex on the membrane were also suppressed. The results suggest that diabetic Plin5-KO mice are resistant to type 1 diabetes-induced heart malfunction due to the suppression of the diacylglycerol/ceramide-protein kinase C pathway and of excessive ROS generation by NADPH oxidase.
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47
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Goeritzer M, Schlager S, Radovic B, Madreiter CT, Rainer S, Thomas G, Lord CC, Sacks J, Brown AL, Vujic N, Obrowsky S, Sachdev V, Kolb D, Chandak PG, Graier WF, Sattler W, Brown JM, Kratky D. Deletion of CGI-58 or adipose triglyceride lipase differently affects macrophage function and atherosclerosis. J Lipid Res 2014; 55:2562-75. [PMID: 25316883 PMCID: PMC4242449 DOI: 10.1194/jlr.m052613] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cellular TG stores are efficiently hydrolyzed by adipose TG lipase (ATGL). Its coactivator comparative gene identification-58 (CGI-58) strongly increases ATGL-mediated TG catabolism in cell culture experiments. To investigate the consequences of CGI-58 deficiency in murine macrophages, we generated mice with a targeted deletion of CGI-58 in myeloid cells (macCGI-58(-/-) mice). CGI-58(-/-) macrophages accumulate intracellular TG-rich lipid droplets and have decreased phagocytic capacity, comparable to ATGL(-/-) macrophages. In contrast to ATGL(-/-) macrophages, however, CGI-58(-/-) macrophages have intact mitochondria and show no indications of mitochondrial apoptosis and endoplasmic reticulum stress, suggesting that TG accumulation per se lacks a significant role in processes leading to mitochondrial dysfunction. Another notable difference is the fact that CGI-58(-/-) macrophages adopt an M1-like phenotype in vitro. Finally, we investigated atherosclerosis susceptibility in macCGI-58/ApoE-double KO (DKO) animals. In response to high-fat/high-cholesterol diet feeding, DKO animals showed comparable plaque formation as observed in ApoE(-/-) mice. In agreement, antisense oligonucleotide-mediated knockdown of CGI-58 in LDL receptor(-/-) mice did not alter atherosclerosis burden in the aortic root. These results suggest that macrophage function and atherosclerosis susceptibility differ fundamentally in these two animal models with disturbed TG catabolism, showing a more severe phenotype by ATGL deficiency.
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Affiliation(s)
- Madeleine Goeritzer
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Stefanie Schlager
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Branislav Radovic
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Corina T Madreiter
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Silvia Rainer
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Gwynneth Thomas
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Caleb C Lord
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jessica Sacks
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Amanda L Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Nemanja Vujic
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Sascha Obrowsky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Vinay Sachdev
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Dagmar Kolb
- Center for Medical Research/Institute of Cell Biology, Histology, and Embryology, Medical University of Graz, Graz, Austria
| | - Prakash G Chandak
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Wolfgang Sattler
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
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48
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Feichtinger RG, Sperl W, Bauer JW, Kofler B. Mitochondrial dysfunction: a neglected component of skin diseases. Exp Dermatol 2014; 23:607-14. [PMID: 24980550 DOI: 10.1111/exd.12484] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2014] [Indexed: 12/20/2022]
Abstract
Aberrant mitochondrial structure and function influence tissue homeostasis and thereby contribute to multiple human disorders and ageing. Ten per cent of patients with primary mitochondrial disorders present skin manifestations that can be categorized into hair abnormalities, rashes, pigmentation abnormalities and acrocyanosis. Less attention has been paid to the fact that several disorders of the skin are linked to alterations of mitochondrial energy metabolism. This review article summarizes the contribution of mitochondrial pathology to both common and rare skin diseases. We explore the intriguing observation that a wide array of skin disorders presents with primary or secondary mitochondrial pathology and that a variety of molecular defects can cause dysfunctional mitochondria. Among them are mutations in mitochondrial- and nuclear DNA-encoded subunits and assembly factors of oxidative phosphorylation (OXPHOS) complexes; mutations in intermediate filament proteins involved in linking, moving and shaping of mitochondria; and disorders of mitochondrial DNA metabolism, fatty acid metabolism and heme synthesis. Thus, we assume that mitochondrial involvement is the rule rather than the exception in skin diseases. We conclude the article by discussing how improving mitochondrial function can be beneficial for aged skin and can be used as an adjunct therapy for certain skin disorders. Consideration of mitochondrial energy metabolism in the skin creates a new perspective for both dermatologists and experts in metabolic disease.
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Affiliation(s)
- René G Feichtinger
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
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49
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Brahma MK, Adam RC, Pollak NM, Jaeger D, Zierler KA, Pöcher N, Schreiber R, Romauch M, Moustafa T, Eder S, Ruelicke T, Preiss-Landl K, Lass A, Zechner R, Haemmerle G. Fibroblast growth factor 21 is induced upon cardiac stress and alters cardiac lipid homeostasis. J Lipid Res 2014; 55:2229-41. [PMID: 25176985 DOI: 10.1194/jlr.m044784] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Fibroblast growth factor 21 (FGF21) is a PPARα-regulated gene elucidated in the liver of PPARα-deficient mice or PPARα agonist-treated mice. Mice globally lacking adipose triglyceride lipase (ATGL) exhibit a marked defect in TG catabolism associated with impaired PPARα-activated gene expression in the heart and liver, including a drastic reduction in hepatic FGF21 mRNA expression. Here we show that FGF21 mRNA expression is markedly increased in the heart of ATGL-deficient mice accompanied by elevated expression of endoplasmic reticulum (ER) stress markers, which can be reversed by reconstitution of ATGL expression in cardiac muscle. In line with this assumption, the induction of ER stress increases FGF21 mRNA expression in H9C2 cardiomyotubes. Cardiac FGF21 expression was also induced upon fasting of healthy mice, implicating a role of FGF21 in cardiac energy metabolism. To address this question, we generated and characterized mice with cardiac-specific overexpression of FGF21 (CM-Fgf21). FGF21 was efficiently secreted from cardiomyocytes of CM-Fgf21 mice, which moderately affected cardiac TG homeostasis, indicating a role for FGF21 in cardiac energy metabolism. Together, our results show that FGF21 expression is activated upon cardiac ER stress linked to defective lipolysis and that a persistent increase in circulating FGF21 levels interferes with cardiac and whole body energy homeostasis.
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Affiliation(s)
- Manoja K Brahma
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Rene C Adam
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Nina M Pollak
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Doris Jaeger
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Kathrin A Zierler
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Nadja Pöcher
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Matthias Romauch
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Tarek Moustafa
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Sandra Eder
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Thomas Ruelicke
- Biomodels Austria University of Veterinary Medicine, 1210 Vienna, Austria and Institute of Laboratory Animal Science, University of Veterinary Medicine, 1210 Vienna, Austria
| | | | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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50
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Nielsen TS, Jessen N, Jørgensen JOL, Møller N, Lund S. Dissecting adipose tissue lipolysis: molecular regulation and implications for metabolic disease. J Mol Endocrinol 2014; 52:R199-222. [PMID: 24577718 DOI: 10.1530/jme-13-0277] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipolysis is the process by which triglycerides (TGs) are hydrolyzed to free fatty acids (FFAs) and glycerol. In adipocytes, this is achieved by sequential action of adipose TG lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase. The activity in the lipolytic pathway is tightly regulated by hormonal and nutritional factors. Under conditions of negative energy balance such as fasting and exercise, stimulation of lipolysis results in a profound increase in FFA release from adipose tissue (AT). This response is crucial in order to provide the organism with a sufficient supply of substrate for oxidative metabolism. However, failure to efficiently suppress lipolysis when FFA demands are low can have serious metabolic consequences and is believed to be a key mechanism in the development of type 2 diabetes in obesity. As the discovery of ATGL in 2004, substantial progress has been made in the delineation of the remarkable complexity of the regulatory network controlling adipocyte lipolysis. Notably, regulatory mechanisms have been identified on multiple levels of the lipolytic pathway, including gene transcription and translation, post-translational modifications, intracellular localization, protein-protein interactions, and protein stability/degradation. Here, we provide an overview of the recent advances in the field of AT lipolysis with particular focus on the molecular regulation of the two main lipases, ATGL and HSL, and the intracellular and extracellular signals affecting their activity.
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Affiliation(s)
- Thomas Svava Nielsen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Jessen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Jens Otto L Jørgensen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Møller
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Sten Lund
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
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