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Li J, Wang R, Chen Q, Tian Y, Gao L, Lei A. Salidroside improves porcine oocyte maturation and subsequent embryonic development by promoting lipid metabolism. Theriogenology 2022; 192:89-96. [DOI: 10.1016/j.theriogenology.2022.08.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 11/28/2022]
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Wang Y, Liu Q, Kang SG, Huang K, Tong T. Dietary Bioactive Ingredients Modulating the cAMP Signaling in Diabetes Treatment. Nutrients 2021; 13:nu13093038. [PMID: 34578916 PMCID: PMC8467569 DOI: 10.3390/nu13093038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 02/06/2023] Open
Abstract
As the prevalence of diabetes increases progressively, research to develop new therapeutic approaches and the search for more bioactive compounds are attracting more attention. Over the past decades, studies have suggested that cyclic adenosine monophosphate (cAMP), the important intracellular second messenger, is a key regulator of metabolism and glucose homeostasis in diverse physiopathological states in multiple organs including the pancreas, liver, gut, skeletal muscle, adipose tissues, brain, and kidney. The multiple characteristics of dietary compounds and their favorable influence on diabetes pathogenesis, as well as their intersections with the cAMP signaling pathway, indicate that these compounds have a beneficial effect on the regulation of glucose homeostasis. In this review, we outline the current understanding of the diverse functions of cAMP in different organs involved in glucose homeostasis and show that a diversity of bioactive ingredients from foods activate or inhibit cAMP signaling, resulting in the improvement of the diabetic pathophysiological process. It aims to highlight the diabetes-preventative or -therapeutic potential of dietary bioactive ingredients targeting cAMP signaling.
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Affiliation(s)
- Yanan Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China;
| | - Qing Liu
- Jilin Green Food Engineering Research Institute, Changchun 130022, China;
| | - Seong-Gook Kang
- Department of Food Engineering, Mokpo National University, Muangun 58554, Korea;
| | - Kunlun Huang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China;
- Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
- Correspondence: (K.H.); (T.T.)
| | - Tao Tong
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China;
- Correspondence: (K.H.); (T.T.)
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3
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Brejchova K, Radner FPW, Balas L, Paluchova V, Cajka T, Chodounska H, Kudova E, Schratter M, Schreiber R, Durand T, Zechner R, Kuda O. Distinct roles of adipose triglyceride lipase and hormone-sensitive lipase in the catabolism of triacylglycerol estolides. Proc Natl Acad Sci U S A 2021; 118:e2020999118. [PMID: 33372146 PMCID: PMC7812821 DOI: 10.1073/pnas.2020999118] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Branched esters of palmitic acid and hydroxy stearic acid are antiinflammatory and antidiabetic lipokines that belong to a family of fatty acid (FA) esters of hydroxy fatty acids (HFAs) called FAHFAs. FAHFAs themselves belong to oligomeric FA esters, known as estolides. Glycerol-bound FAHFAs in triacylglycerols (TAGs), named TAG estolides, serve as metabolite reservoir of FAHFAs mobilized by lipases upon demand. Here, we characterized the involvement of two major metabolic lipases, adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), in TAG estolide and FAHFA degradation. We synthesized a library of 20 TAG estolide isomers with FAHFAs varying in branching position, chain length, saturation grade, and position on the glycerol backbone and developed an in silico mass spectra library of all predicted catabolic intermediates. We found that ATGL alone or coactivated by comparative gene identification-58 efficiently liberated FAHFAs from TAG estolides with a preference for more compact substrates where the estolide branching point is located near the glycerol ester bond. ATGL was further involved in transesterification and remodeling reactions leading to the formation of TAG estolides with alternative acyl compositions. HSL represented a much more potent estolide bond hydrolase for both TAG estolides and free FAHFAs. FAHFA and TAG estolide accumulation in white adipose tissue of mice lacking HSL argued for a functional role of HSL in estolide catabolism in vivo. Our data show that ATGL and HSL participate in the metabolism of estolides and TAG estolides in distinct manners and are likely to affect the lipokine function of FAHFAs.
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Affiliation(s)
- Kristyna Brejchova
- Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic
| | | | - Laurence Balas
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS, École Nationale Supérieure de Chimie de Montpellier, Faculté de Pharmacie, Université de Montpellier, 34093 Montpellier, France
| | - Veronika Paluchova
- Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic
| | - Tomas Cajka
- Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic
| | - Hana Chodounska
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague 6, Czech Republic
| | - Eva Kudova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague 6, Czech Republic
| | | | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Thierry Durand
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS, École Nationale Supérieure de Chimie de Montpellier, Faculté de Pharmacie, Université de Montpellier, 34093 Montpellier, France
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria;
- BioTechMed-Graz, 8010 Graz, Austria
| | - Ondrej Kuda
- Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic;
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Recazens E, Mouisel E, Langin D. Hormone-sensitive lipase: sixty years later. Prog Lipid Res 2020; 82:101084. [PMID: 33387571 DOI: 10.1016/j.plipres.2020.101084] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/12/2020] [Accepted: 12/24/2020] [Indexed: 12/19/2022]
Abstract
Hormone-sensitive lipase (HSL) was initially characterized as the hormonally regulated neutral lipase activity responsible for the breakdown of triacylglycerols into fatty acids in adipose tissue. This review aims at providing up-to-date information on structural properties, regulation of expression, activity and function as well as therapeutic potential. The lipase is expressed as different isoforms produced from tissue-specific alternative promoters. All isoforms are composed of an N-terminal domain and a C-terminal catalytic domain within which a regulatory domain containing the phosphorylation sites is embedded. Some isoforms possess additional N-terminal regions. The catalytic domain shares similarities with bacteria, fungus and vascular plant proteins but not with other mammalian lipases. HSL singularity is provided by regulatory and N-terminal domains sharing no homology with other proteins. HSL has a broad substrate specificity compared to other neutral lipases. It hydrolyzes acylglycerols, cholesteryl and retinyl esters among other substrates. A novel role of HSL, independent of its enzymatic function, has recently been described in adipocytes. Clinical studies revealed dysregulations of HSL expression and activity in disorders, such as lipodystrophy, obesity, type 2 diabetes and cancer-associated cachexia. Development of specific inhibitors positions HSL as a pharmacological target for the treatment of metabolic complications.
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Affiliation(s)
- Emeline Recazens
- Institute of Metabolic and Cardiovascular Diseases, Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1297, 31432 Toulouse, France; University of Toulouse, Paul Sabatier University, UMR1297, Toulouse, France
| | - Etienne Mouisel
- Institute of Metabolic and Cardiovascular Diseases, Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1297, 31432 Toulouse, France; University of Toulouse, Paul Sabatier University, UMR1297, Toulouse, France
| | - Dominique Langin
- Institute of Metabolic and Cardiovascular Diseases, Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1297, 31432 Toulouse, France; University of Toulouse, Paul Sabatier University, UMR1297, Toulouse, France; Franco-Czech Laboratory for Clinical Research on Obesity, Third Faculty of Medicine, Prague and Paul Sabatier University, Toulouse, France; Toulouse University Hospitals, Laboratory of Clinical Biochemistry, Toulouse, France.
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5
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Arredondo-Amador M, Zambrano C, Kulyté A, Luján J, Hu K, Sánchez de Medina F, Scheer FAJL, Arner P, Ryden M, Martínez-Augustin O, Garaulet M. Circadian Rhythms in Hormone-sensitive Lipase in Human Adipose Tissue: Relationship to Meal Timing and Fasting Duration. J Clin Endocrinol Metab 2020; 105:5877911. [PMID: 32725188 PMCID: PMC7538104 DOI: 10.1210/clinem/dgaa492] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Fat mobilization in adipose tissue (AT) has a specific timing. However, circadian rhythms in the activity of the major enzyme responsible for fat mobilization, hormone-sensitive lipase (HSL), have not been demonstrated in humans. OBJECTIVE To analyze in a cross-sectional study whether there is an endogenous circadian rhythm in HSL activity in human AT ex vivo and whether rhythm characteristics are related to food timing or fasting duration. METHODS Abdominal AT biopsies were obtained from 18 severely obese participants (age: 46 ± 11 years; body mass index 42 ± 6 kg/m2) who underwent laparoscopic gastric bypass. Twenty-four-hour rhythms of HSL activity and LIPE (HSL transcript in humans) expression in subcutaneous AT were analyzed together with habitual food timing and night fasting duration. RESULTS HSL activity exhibited a circadian rhythm (P = .023) and reached the maximum value at circadian time 16 (CT) that corresponded to around midnight (relative local clock time. Similarly, LIPE displayed a circadian rhythm with acrophase also at night (P = .0002). Participants with longer night fasting duration >11.20 hours displayed almost double the amplitude (1.91 times) in HSL activity rhythm than those with short duration (P = .013); while habitual early diners (before 21:52 hours) had 1.60 times higher amplitude than late diners (P = .035). CONCLUSIONS Our results demonstrate circadian rhythms in HSL activity and may lead to a better understanding of the intricate relationships between food timing, fasting duration and body fat regulation.
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Affiliation(s)
- María Arredondo-Amador
- Department of Pharmacology, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Investigación Biosanitaria ibs, Granada, School of Pharmacy, University of Granada, Granada, Spain
| | - Carolina Zambrano
- Department of Physiology, Biomedical Research Institute of Murcia (IMIB)-Arrixaca, University of Murcia, Murcia, Spain
| | - Agné Kulyté
- Endocrinology Unit, Department of Medicine (H7) Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Juán Luján
- General Surgery Service, University Hospital Virgen de la Arrixaca, Murcia, Spain
| | - Kun Hu
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Boston, Massachusetts; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
| | - Fermín Sánchez de Medina
- Department of Pharmacology, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Investigación Biosanitaria ibs, Granada, School of Pharmacy, University of Granada, Granada, Spain
| | - Frank A J L Scheer
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Boston, Massachusetts; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
| | - Peter Arner
- Endocrinology Unit, Department of Medicine (H7) Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Ryden
- Endocrinology Unit, Department of Medicine (H7) Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Investigación Biosanitaria ibs, Granada, Instituto de Nutrición y Tecnología de los Alimentos José Mataix, University of Granada, Granada, Spain
| | - Marta Garaulet
- Department of Physiology, Biomedical Research Institute of Murcia (IMIB)-Arrixaca, University of Murcia, Murcia, Spain
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Boston, Massachusetts; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
- Correspondence and Reprint Requests: Marta Garaulet, Department of Physiology, University of Murcia, s/n. 30100, Murcia, Spain; or Division of Sleep and Circadian Disorders, Brigham and Women’s, Boston, MA, USA. E-mail: ;
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Hofer P, Taschler U, Schreiber R, Kotzbeck P, Schoiswohl G. The Lipolysome-A Highly Complex and Dynamic Protein Network Orchestrating Cytoplasmic Triacylglycerol Degradation. Metabolites 2020; 10:E147. [PMID: 32290093 PMCID: PMC7240967 DOI: 10.3390/metabo10040147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/03/2020] [Accepted: 04/08/2020] [Indexed: 12/25/2022] Open
Abstract
The catabolism of intracellular triacylglycerols (TAGs) involves the activity of cytoplasmic and lysosomal enzymes. Cytoplasmic TAG hydrolysis, commonly termed lipolysis, is catalyzed by the sequential action of three major hydrolases, namely adipose triglyceride lipase, hormone-sensitive lipase, and monoacylglycerol lipase. All three enzymes interact with numerous protein binding partners that modulate their activity, cellular localization, or stability. Deficiencies of these auxiliary proteins can lead to derangements in neutral lipid metabolism and energy homeostasis. In this review, we summarize the composition and the dynamics of the complex lipolytic machinery we like to call "lipolysome".
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Affiliation(s)
- Peter Hofer
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; (P.H.); (U.T.); (R.S.)
| | - Ulrike Taschler
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; (P.H.); (U.T.); (R.S.)
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; (P.H.); (U.T.); (R.S.)
| | - Petra Kotzbeck
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria;
| | - Gabriele Schoiswohl
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; (P.H.); (U.T.); (R.S.)
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Zhuan Q, Ma H, Chen J, Luo Y, Luo Y, Gao L, Hou Y, Zhu S, Fu X. Cytoplasm lipids can be modulated through hormone-sensitive lipase and are related to mitochondrial function in porcine IVM oocytes. Reprod Fertil Dev 2020; 32:667-675. [DOI: 10.1071/rd19047] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 11/14/2019] [Indexed: 12/16/2022] Open
Abstract
Intracellular lipids provide energy for oocyte maturation and development. Triglycerides are the main components of cytoplasm lipid droplets, and hydrolysis of triglycerides requires several lipase-mediated steps. The aim of this study was to determine the effects of the β-adrenoceptor agonist isoproterenol (ISO) and the hormone-sensitive lipase (HSL) inhibitor CAY10499 on the IVM of porcine oocytes. ISO (5mg L−1) and CAY10499 (20mg L−1) had positive and negative effects respectively on invitro oocyte maturation and subsequent embryo development. The rates of polar body extrusion, cleavage and blastocyst formation were significantly higher in the ISO-treated group than the control and CAY10499-treated groups. ISO treatment also upregulated intracellular cAMP levels in comparison with the control group, while CAY10499 significantly increased the triglyceride content of matured oocytes when compared with other groups, consistent with the observed decrease in LIPE (HSL) mRNA levels. Furthermore, the inhibitory effects of CAY10499 included decreases in mitochondrial membrane potential and mitochondrial temperature. These results indicate that ISO has a positive effect on the IVM of porcine oocytes, and that intracellular lipid metabolism can be modulated by CAY10499 through inhibition of HSL and is closely related to mitochondrial function.
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Impact of skeletal muscle IL-6 on subcutaneous and visceral adipose tissue metabolism immediately after high- and moderate-intensity exercises. Pflugers Arch 2019; 472:217-233. [PMID: 31781893 DOI: 10.1007/s00424-019-02332-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 12/28/2022]
Abstract
White adipose tissue is a major energy reserve for the body and is essential for providing fatty acids for other tissues when needed. Skeletal muscle interleukin-6 (IL-6) has been shown to be secreted from the working muscle and has been suggested to signal to adipose tissue and enhance lipolysis. The aim of the present study was to investigate the role of skeletal muscle IL-6 in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) lipolysis and glyceroneogenesis with prolonged moderate-intensity exercise and high-intensity exercise in mice. Female inducible muscle-specific IL-6 knockout (IL-6 iMKO) mice and littermate control (Floxed) mice performed a single exercise bout for either 120 min at 16 m/min and 10° slope (moderate intensity) or 30 min at 20 m/min and 10° slope (high intensity), or they remained rested (rest). Visceral and subcutaneous adipose tissues, quadriceps muscles, and blood were quickly obtained. Plasma IL-6 increased in Floxed mice but not in IL-6 iMKO mice with high-intensity exercise. VAT signal transducer and activator of transcription (STAT)3Tyr705 phosphorylation was lower, and VAT hormone-sensitive lipase (HSL)Ser563 phosphorylation was higher in IL-6 iMKO mice than in Floxed mice at rest. Furthermore, HSLSer563 and HSLSer660 phosphorylation increased in VAT and phosphoenolpyruvate carboxykinase protein decreased in SAT with moderate-intensity exercise in both genotypes. On the other hand, both exercise protocols increased pyruvate dehydrogenaseSer232 phosphorylation in VAT only in IL-6 iMKO mice and decreased tumor necrosis factor-α messenger RNA in SAT and VAT only in Floxed mice. In conclusion, the present findings suggest that skeletal muscle IL-6 regulates markers of lipolysis in VAT in the basal state and pyruvate availability for glyceroneogenesis in VAT with exercise. Moreover, skeletal muscle IL-6 may contribute to exercise-induced anti-inflammatory effects in SAT and VAT.
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Ramshanker N, Jessen N, Voss TS, Pedersen SB, Jørgensen JOL, Nielsen TS, Frystyk J, Møller N. Effects of short-term prednisolone treatment on indices of lipolysis and lipase signaling in abdominal adipose tissue in healthy humans. Metabolism 2019; 99:1-10. [PMID: 31260678 DOI: 10.1016/j.metabol.2019.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/14/2019] [Accepted: 06/25/2019] [Indexed: 01/24/2023]
Abstract
BACKGROUND Glucocorticoid (GC) excess increases lipolysis, circulating free fatty acid concentrations and lipid oxidation rates in humans. In vitro and animal studies have shown that GCs increase adipocyte ATGL and HSL mRNA contents and HSL phosphorylations, but the effects of GC on in vivo lipase signaling in humans are uncertain. Our study was designed to test how GC administration affects ATGL and HSL related signals in human adipose tissue. MATERIAL AND METHODS Nine healthy young men underwent 5 days administration of 37.5 mg prednisolone/d in a randomized, double-blinded, placebo-controlled crossover design. At the end of each 5 d period the subjects were studied after an overnight fast for 6.5 h including a basal period and a 2½ h hyperinsulinemic euglycemic clamp. Adipose tissue biopsies were sampled from the abdominal subcutaneous adipose tissue at the end of the basal period and the clamp. RESULTS GC treatment increased serum FFA concentrations and comparative gene identification-58 (CGI-58) mRNA - an ATGL activator - and decreased G0/G1 switch 2 gene (G0S2) mRNA - an ATGL inhibitor - in adipose tissue biopsies. In addition, pro-lipolytic ser563 HSL phosphorylations and protein kinase A (PKA) phosphorylation of PLIN1 (Perilipin-1) increased. The transcripts of ANGPTL4 (Angiopoietin-like 4) mRNA - a regulator of circulating triglycerides - were elevated by GC; as were CIDE (Cell-death Inducing DNA fragmentation factor-α-like Effector)-A and CIDE-C mRNA transcripts indicative of concurrent stimulation of lipolysis and lipogenesis. Finally GCs reduced insulin receptor phosphorylation, and Akt protein levels. CONCLUSIONS High dose GC administration to humans leads to pro-lipolytic alterations of CGI-58, G0S2 and ANGPTL4 mRNA transcripts, increases PKA signaling to lipolysis and inhibits the insulin signal in adipose tissue. The increased CIDE-A and CIDE-C mRNA levels suggest concomitant stimulation of lipolysis and lipid storage.
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Affiliation(s)
- Nilani Ramshanker
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark.
| | - Niels Jessen
- Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 99, DK-8200 Aarhus N, Denmark; Department of Clinical Pharmacology, Wilhelm Meyers Allé 4, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Thomas Schmidt Voss
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark
| | - Steen Bønløkke Pedersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle-Juul Jensens Blvd. 99, DK-8200 Aarhus N, Denmark
| | - Jens Otto Lunde Jørgensen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle-Juul Jensens Blvd. 99, DK-8200 Aarhus N, Denmark
| | - Thomas Svava Nielsen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3A, DK-2200 Copenhagen N, Denmark
| | - Jan Frystyk
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blvd. 165, DK-8200 Aarhus N, Denmark; Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Palle-Juul Jensens Blvd. 99, DK-8200 Aarhus N, Denmark
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10
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Kopietz F, Berggreen C, Larsson S, Säll J, Ekelund M, Sakamoto K, Degerman E, Holm C, Göransson O. AMPK activation by A-769662 and 991 does not affect catecholamine-induced lipolysis in human adipocytes. Am J Physiol Endocrinol Metab 2018; 315:E1075-E1085. [PMID: 30253109 DOI: 10.1152/ajpendo.00110.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Activation of AMP-activated protein kinase (AMPK) is considered an attractive strategy for the treatment of type 2 diabetes. Favorable metabolic effects of AMPK activation are mainly observed in skeletal muscle and liver tissue, whereas the effects in human adipose tissue are only poorly understood. Previous studies, which largely employed the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), suggest an antilipolytic role of AMPK in adipocytes. The aim of this work was to reinvestigate the role of AMPK in the regulation of lipolysis, using the novel allosteric small-molecule AMPK activators A-769662 and 991, with a focus on human adipocytes. For this purpose, human primary subcutaneous adipocytes were treated with A-769662, 991, or AICAR, as a control, before being stimulated with isoproterenol. AMPK activity status, glycerol release, and the phosphorylation of hormone-sensitive lipase (HSL), a key regulator of lipolysis, were then monitored. Our results show that both A-769662 and 991 activated AMPK to a level that was similar to, or greater than, that induced by AICAR. In contrast to AICAR, which as expected was antilipolytic, neither A-769662 nor 991 affected lipolysis in human adipocytes, although 991 treatment led to altered HSL phosphorylation. Furthermore, we suggest that HSL Ser660 is an important regulator of lipolytic activity in human adipocytes. These data suggest that the antilipolytic effect observed with AICAR in previous studies is, at least to some extent, AMPK independent.
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Affiliation(s)
- Franziska Kopietz
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | | | - Sara Larsson
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Johanna Säll
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Mikael Ekelund
- Surgery, Department of Clinical Sciences Malmö, Lund University , Malmö , Sweden
| | | | - Eva Degerman
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Cecilia Holm
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Olga Göransson
- Department of Experimental Medical Science, Lund University , Lund , Sweden
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Impact of skeletal muscle IL-6 on regulation of liver and adipose tissue metabolism during fasting. Pflugers Arch 2018; 470:1597-1613. [PMID: 30069669 DOI: 10.1007/s00424-018-2185-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/21/2018] [Accepted: 07/12/2018] [Indexed: 01/05/2023]
Abstract
The liver and adipose tissue are important tissues in whole-body metabolic regulation during fasting. Interleukin 6 (IL-6) is a cytokine shown to be secreted from contracting muscle in humans and suggested to signal to the liver and adipose tissue. Furthermore, skeletal muscle IL-6 has been proposed to play a role during fasting. Therefore the aim of the present study was to investigate the role of skeletal muscle IL-6 in the regulation of substrate production in the liver and adipose tissue during fasting. Male skeletal muscle-specific IL-6 knockout (IL-6 MKO) mice and littermate floxed (control) mice fasted for 6 or 18 h (6 h fasting or 18 h fasting) with corresponding fed control groups (6 h fed or 18 h fed) and liver and adipose tissue were quickly obtained. Plasma β-hydroxybutyrate increased and hepatic glucose, lactate and glycogen decreased with fasting. In addition, fasting increased phosphoenolpyruvate carboxykinase protein and phosphorylation of pyruvate dehydrogenase (PDH) in the liver as well as hormone-sensitive lipase (HSL)Ser660 and HSLSer563 phosphorylation, PDH phosphorylation, adipose triglyceride lipase phosphorylation and perilipin phosphorylation and protein content in adipose tissue without any effect of lack of skeletal muscle IL-6. In conclusion, fasting induced regulation of enzymes in adipose tissue lipolysis and glyceroneogenesis as well as regulation of hepatic gluconeogenic capacity and hepatic substrate utilization in mice. However, skeletal muscle IL-6 was not required for these fasting-induced effects, but had minor effects on markers of lipolysis and glyceroneogenesis in adipose tissue as well as markers of hepatic gluconeogenesis in the fed state.
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12
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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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13
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Rogne M, Chu DT, Küntziger TM, Mylonakou MN, Collas P, Tasken K. OPA1-anchored PKA phosphorylates perilipin 1 on S522 and S497 in adipocytes differentiated from human adipose stem cells. Mol Biol Cell 2018; 29:1487-1501. [PMID: 29688805 PMCID: PMC6014102 DOI: 10.1091/mbc.e17-09-0538] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Optic atrophy 1 (OPA1) is the A-kinase anchoring protein targeting the pool of protein kinase A (PKA) responsible for perilipin 1 phosphorylation, a gatekeeper for lipolysis. However, the involvement of OPA1-bound PKA in the downstream regulation of lipolysis is unknown. Here we show up-regulation and relocation of OPA1 from mitochondria to lipid droplets during adipocytic differentiation of human adipose stem cells. We employed various biochemical and immunological approaches to demonstrate that OPA1-bound PKA phosphorylates perilipin 1 at S522 and S497 on lipolytic stimulation. We show that the first 30 amino acids of OPA1 are essential for its lipid droplet localization as is OMA1-dependent processing. Finally, our results indicate that presence of OPA1 is necessary for lipolytic phosphorylation of downstream targets. Our results show for the first time, to our knowledge, how OPA1 mediates adrenergic control of lipolysis in human adipocytes by regulating phosphorylation of perilipin 1.
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Affiliation(s)
- Marie Rogne
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, 0318 Oslo, Norway
| | - Dinh-Toi Chu
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, 0318 Oslo, Norway
| | | | - Maria-Niki Mylonakou
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, 0318 Oslo, Norway
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0318 Oslo, Norway.,Norewegian Center for Stem Cell Research, Department of Immunology and Transfusion Medicine, Oslo University Hospital, 0424 Oslo, Norway
| | - Kjetil Tasken
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, 0318 Oslo, Norway.,Department of Cancer Immunology, Institute of Cancer Research, Oslo University Hospital, 0424 Oslo, Norway
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14
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Bergan-Roller HE, Sheridan MA. The growth hormone signaling system: Insights into coordinating the anabolic and catabolic actions of growth hormone. Gen Comp Endocrinol 2018; 258:119-133. [PMID: 28760716 DOI: 10.1016/j.ygcen.2017.07.028] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/19/2017] [Accepted: 07/27/2017] [Indexed: 12/16/2022]
Abstract
Although growth hormone (GH) is a multifunctional factor that coordinates various aspects of feeding, reproduction, osmoregulation, and immune system function, perhaps two of its most studied actions are the regulation of growth and metabolism, particularly lipid metabolism. In this review, we describe the major growth-promoting and lipid metabolic actions of GH and then discuss how the GH system regulates these actions. Numerous intrinsic and extrinsic factors provide information about the metabolic status of the organism and influence the production of release of GH. The actions of GH are mediated by GH receptors (GHR), which are widely distributed among tissues. Teleosts possess multiple forms of GHRs that arose through the evolution of this group. Modulation of tissue responsiveness to GH is regulated by molecular and functional expression of GHRs, and in teleosts GHR subtypes, by various factors that reflect the metabolic and growth status of the organism, including nutritional state. The action of GH is propagated by the linkage of GHRs to several cellular effector systems, including JAK-STAT, ERK, PI3K-Akt, and PKC. The differential activation of these pathways, which is governed by nutrient status, underlies GH stimulation of growth or GH stimulation of lipolysis. Taken together, the multi-functional actions of GH are determined by the distribution and abundance of GHRs (and GHR subtypes in teleosts) as well as by the GHR-effector system linkages.
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Affiliation(s)
| | - Mark A Sheridan
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409 USA.
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15
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Bertholdt L, Gudiksen A, Stankiewicz T, Villesen I, Tybirk J, van Hall G, Bangsbo J, Plomgaard P, Pilegaard H. Impact of training state on fasting-induced regulation of adipose tissue metabolism in humans. J Appl Physiol (1985) 2017; 124:729-740. [PMID: 29191981 DOI: 10.1152/japplphysiol.00664.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recruitment of fatty acids from adipose tissue is increased during fasting. However, the molecular mechanisms behind fasting-induced metabolic regulation in human adipose tissue and the potential impact of training state in this are unknown. Therefore the aim of the present study was to investigate 1) fasting-induced regulation of lipolysis and glyceroneogenesis in human adipose tissue as well as 2) the impact of training state on basal oxidative capacity and fasting-induced metabolic regulation in human adipose tissue. Untrained [maximal oxygen uptake (V̇o2max) < 45 ml·min-1·kg-1] and trained subjects (V̇o2max > 55 ml·min-1·kg-1) fasted for 36 h, and abdominal subcutaneous adipose tissue biopsies were obtained 2, 12, 24, and 36 h after a standardized meal. Adipose tissue oxidative phosphorylation complexes, phosphoenolpyruvate carboxykinase, and pyruvate dehydrogenase (PDH)-E1α protein as well as PDH kinase (PDK) 2, PDK4, and PDH phosphatase 2 mRNA content were higher in trained subjects than in untrained subjects. In addition, trained subjects had higher adipose tissue hormone-sensitive lipase Ser660 phosphorylation and adipose triglyceride lipase protein content as well as higher plasma free fatty acid concentration than untrained subjects during fasting. Moreover, adipose tissue PDH phosphorylation increased with fasting only in trained subjects. Taken together, trained subjects seem to possess higher basal adipose tissue oxidative capacity as well as higher capacity for regulation of lipolysis and for providing substrate for glyceroneogenesis in adipose tissue during fasting than untrained subjects. NEW & NOTEWORTHY This study shows for the first time higher protein content of lipolytic enzymes and higher oxidative phosphorylation protein in adipose tissue from trained subjects than from untrained subjects during fasting. Furthermore, trained subjects had higher capacity for adipose tissue glyceroneogenesis than untrained subjects.
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Affiliation(s)
- Lærke Bertholdt
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen , Copenhagen , Denmark
| | - Anders Gudiksen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen , Copenhagen , Denmark
| | - Tomasz Stankiewicz
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen , Copenhagen , Denmark
| | - Ida Villesen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen , Copenhagen , Denmark
| | - Jonas Tybirk
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Gerrit van Hall
- Clinical Metabolomics Core Facility, Department of Clinical Biochemistry, Rigshospitalet, and Department of Biomedical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen , Copenhagen , Denmark
| | - Peter Plomgaard
- Department of Clinical Biochemistry, Rigshospitalet, Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen , Copenhagen , Denmark
| | - Henriette Pilegaard
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen , Copenhagen , Denmark
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16
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Engin A. Fat Cell and Fatty Acid Turnover in Obesity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 960:135-160. [PMID: 28585198 DOI: 10.1007/978-3-319-48382-5_6] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The ratio of free fatty acid (FFA) turnover decreases significantly with the expansion of white adipose tissue. Adipose tissue and dietary saturated fatty acid levels significantly correlate with an increase in fat cell size and number. Inhibition of adipose triglyceride lipase leads to an accumulation of triglyceride, whereas inhibition of hormone-sensitive lipase leads to the accumulation of diacylglycerol. The G0/G1 switch gene 2 increases lipid content in adipocytes and promotes adipocyte hypertrophy through the restriction of triglyceride turnover. Excess triacylglycerols (TAGs), sterols and sterol esters are surrounded by the phospholipid monolayer surface and form lipid droplets. Following the release of lipid droplets from endoplasmic reticulum, cytoplasmic lipid droplets increase their volume either by local TAG synthesis or by homotypic fusion. The number and the size of lipid droplet distribution is correlated with obesity. Obesity-associated adipocyte death exhibits feature of necrosis-like programmed cell death. NOD-like receptors family pyrin domain containing 3 (NLRP3) inflammasome-dependent caspase-1 activation in hypertrophic adipocytes induces obese adipocyte death by pyroptosis. Actually adipocyte death may be a prerequisite for the transition from hypertrophic to hyperplastic obesity. Major transcriptional factors, CCAAT/enhancer-binding proteins beta and delta, play a central role in the subsequent induction of critical regulators, peroxisome-proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha and sterol regulatory element-binding protein 1, in the transcriptional control of adipogenesis in obesity.Collectively, in this chapter the concept of adipose tissue remodeling in response to adipocyte death or adipogenesis, and the complexity of lipid droplet interactions with the other cellular organelles are reviewed. Furthermore, in addition to lipid droplet growth, the functional link between the adipocyte-specific lipid droplet-associated protein and fatty acid turn-over is also debated.
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Affiliation(s)
- Atilla Engin
- Faculty of Medicine, Department of General Surgery, Gazi University, Besevler, Ankara, Turkey. .,, Mustafa Kemal Mah. 2137. Sok. 8/14, 06520, Cankaya, Ankara, Turkey.
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17
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Hansen JS, Krintel C, Hernebring M, Haataja TJK, de Marè S, Wasserstrom S, Kosinska-Eriksson U, Palmgren M, Holm C, Stenkula KG, Jones HA, Lindkvist-Petersson K. Perilipin 1 binds to aquaporin 7 in human adipocytes and controls its mobility via protein kinase A mediated phosphorylation. Metabolism 2016; 65:1731-1742. [PMID: 27832861 DOI: 10.1016/j.metabol.2016.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 11/23/2022]
Abstract
Accumulating evidence suggests that dysregulated glycerol metabolism contributes to the pathophysiology of obesity and type 2 diabetes. Glycerol efflux from adipocytes is regulated by the aquaglyceroporin AQP7, which is translocated upon hormone stimulation. Here, we propose a molecular mechanism where the AQP7 mobility in adipocytes is dependent on perilipin 1 and protein kinase A. Biochemical analyses combined with ex vivo studies in human primary adipocytes, demonstrate that perilipin 1 binds to AQP7, and that catecholamine activated protein kinase A phosphorylates the N-terminus of AQP7, thereby reducing complex formation. Together, these findings are indicative of how glycerol release is controlled in adipocytes, and may pave the way for the future design of drugs against human metabolic pathologies.
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Affiliation(s)
- Jesper S Hansen
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | - Christian Krintel
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | - Malin Hernebring
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | - Tatu J K Haataja
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | - Sofia de Marè
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | - Sebastian Wasserstrom
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | | | - Madelene Palmgren
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Cecilia Holm
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | - Karin G Stenkula
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
| | - Helena A Jones
- Department of Experimental Medical Science, Lund University, BMC, 221 84, Lund, Sweden
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18
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Yang H, Yang L. Targeting cAMP/PKA pathway for glycemic control and type 2 diabetes therapy. J Mol Endocrinol 2016; 57:R93-R108. [PMID: 27194812 DOI: 10.1530/jme-15-0316] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 05/18/2016] [Indexed: 12/11/2022]
Abstract
In mammals, cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is usually elicited by binding of hormones and neurotransmitters to G protein-coupled receptors (GPCRs). cAMP exerts many of its physiological effects by activating cAMP-dependent protein kinase (PKA), which in turn phosphorylates and regulates the functions of downstream protein targets including ion channels, enzymes, and transcription factors. cAMP/PKA signaling pathway regulates glucose homeostasis at multiple levels including insulin and glucagon secretion, glucose uptake, glycogen synthesis and breakdown, gluconeogenesis, and neural control of glucose homeostasis. This review summarizes recent genetic and pharmacological studies concerning the regulation of glucose homeostasis by cAMP/PKA in pancreas, liver, skeletal muscle, adipose tissues, and brain. We also discuss the strategies for targeting cAMP/PKA pathway for research and potential therapeutic treatment of type 2 diabetes mellitus (T2D).
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Affiliation(s)
- Haihua Yang
- Division of EndocrinologyZhengzhou Children's Hospital, Zhengzhou, Henan, China
| | - Linghai Yang
- Department of PharmacologyUniversity of Washington, Seattle, Washington, USA
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19
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Phosphoprotein network analysis of white adipose tissues unveils deregulated pathways in response to high-fat diet. Sci Rep 2016; 6:25844. [PMID: 27180971 PMCID: PMC4867603 DOI: 10.1038/srep25844] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 04/22/2016] [Indexed: 12/27/2022] Open
Abstract
Despite efforts in the last decade, signaling aberrations associated with obesity remain poorly understood. To dissect molecular mechanisms that define this complex metabolic disorder, we carried out global phosphoproteomic analysis of white adipose tissue (WAT) from mice fed on low-fat diet (LFD) and high-fat diet (HFD). We quantified phosphorylation levels on 7696 peptides, and found significant differential phosphorylation levels in 282 phosphosites from 191 proteins, including various insulin-responsive proteins and metabolic enzymes involved in lipid homeostasis in response to high-fat feeding. Kinase-substrate prediction and integrated network analysis of the altered phosphoproteins revealed underlying signaling modulations during HFD-induced obesity, and suggested deregulation of lipogenic and lipolytic pathways. Mutation of the differentially-regulated novel phosphosite on cytoplasmic acetyl-coA forming enzyme ACSS2 (S263A) upon HFD-induced obesity led to accumulation of serum triglycerides and reduced insulin-responsive AKT phosphorylation as compared to wild type ACSS2, thus highlighting its role in obesity. Altogether, our study presents a comprehensive map of adipose tissue phosphoproteome in obesity and reveals many previously unknown candidate phosphorylation sites for future functional investigation.
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20
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Sahu-Osen A, Montero-Moran G, Schittmayer M, Fritz K, Dinh A, Chang YF, McMahon D, Boeszoermenyi A, Cornaciu I, Russell D, Oberer M, Carman GM, Birner-Gruenberger R, Brasaemle DL. CGI-58/ABHD5 is phosphorylated on Ser239 by protein kinase A: control of subcellular localization. J Lipid Res 2014; 56:109-21. [PMID: 25421061 PMCID: PMC4274058 DOI: 10.1194/jlr.m055004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
CGI-58/ABHD5 coactivates adipose triglyceride lipase (ATGL). In adipocytes, CGI-58 binds to perilipin 1A on lipid droplets under basal conditions, preventing interaction with ATGL. Upon activation of protein kinase A (PKA), perilipin 1A is phosphorylated and CGI-58 rapidly disperses into the cytoplasm, enabling lipase coactivation. Because the amino acid sequence of murine CGI-58 has a predicted PKA consensus sequence of RKYS239S240, we hypothesized that phosphorylation of CGI-58 is involved in this process. We show that Ser239 of murine CGI-58 is a substrate for PKA using phosphoamino acid analysis, MS, and immunoblotting approaches to study phosphorylation of recombinant CGI-58 and endogenous CGI-58 of adipose tissue. Phosphorylation of CGI-58 neither increased nor impaired coactivation of ATGL in vitro. Moreover, Ser239 was not required for CGI-58 function to increase triacylglycerol turnover in human neutral lipid storage disorder fibroblasts that lack endogenous CGI-58. Both CGI-58 and S239A/S240A-mutated CGI-58 localized to perilipin 1A-coated lipid droplets in cells. When PKA was activated, WT CGI-58 dispersed into the cytoplasm, whereas substantial S239A/S240A-mutated CGI-58 remained on lipid droplets. Perilipin phosphorylation also contributed to CGI-58 dispersion. PKA-mediated phosphorylation of CGI-58 is required for dispersion of CGI-58 from perilipin 1A-coated lipid droplets, thereby increasing CGI-58 availability for ATGL coactivation.
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Affiliation(s)
- Anita Sahu-Osen
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Graz, Austria A-8036, and Omics Center Graz, BioTechMed-Graz, Graz, Austria A-8010
| | - Gabriela Montero-Moran
- Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Departments of Nutritional Sciences Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | - Matthias Schittmayer
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Graz, Austria A-8036, and Omics Center Graz, BioTechMed-Graz, Graz, Austria A-8010
| | - Katarina Fritz
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Graz, Austria A-8036, and Omics Center Graz, BioTechMed-Graz, Graz, Austria A-8010
| | - Anna Dinh
- Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Departments of Nutritional Sciences Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | - Yu-Fang Chang
- Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Food Science, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | - Derek McMahon
- Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Departments of Nutritional Sciences Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | | | - Irina Cornaciu
- Institute of Molecular Biosciences, University of Graz, Graz, Austria A-8010
| | - Deanna Russell
- Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Departments of Nutritional Sciences Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | - Monika Oberer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria A-8010
| | - George M Carman
- Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Food Science, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | - Ruth Birner-Gruenberger
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Graz, Austria A-8036, and Omics Center Graz, BioTechMed-Graz, Graz, Austria A-8010
| | - Dawn L Brasaemle
- Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Departments of Nutritional Sciences Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
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21
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Arner P, Langin D. Lipolysis in lipid turnover, cancer cachexia, and obesity-induced insulin resistance. Trends Endocrinol Metab 2014; 25:255-62. [PMID: 24731595 DOI: 10.1016/j.tem.2014.03.002] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 02/19/2014] [Accepted: 03/04/2014] [Indexed: 12/14/2022]
Abstract
Triglycerides in adipose tissue are rapidly mobilized during times of energy needs via lipolysis, a catabolic process that plays important role in whole body triglyceride turnover. Lipolysis is regulated through cell surface receptors via neurotransmitters, hormones, and paracrine factors that activate various intracellular pathways. These pathways converge on the lipid droplet, the site of action of lipases and cofactors. Fat cell lipolysis is also involved in the pathogenesis of metabolic disorders, and recent human studies have underscored its role in disease states such as cancer cachexia and obesity-induced insulin resistance. We highlight here topics and findings with physiological and clinical relevance, namely lipid turnover in human fat cells and the role of lipolysis in cancer cachexia and obesity-induced insulin resistance.
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Affiliation(s)
- Peter Arner
- Karolinska Institutet, Department of Medicine at Karolinska University Hospital, 141 86 Stockholm, Sweden.
| | - Dominique Langin
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases, 31432 Toulouse, France; University of Toulouse, UMR 1048, Paul Sabatier University, 31432 Toulouse, France; Toulouse University Hospitals, Department of Clinical Biochemistry, 31059 Toulouse, France
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22
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Louche K, Badin PM, Montastier E, Laurens C, Bourlier V, de Glisezinski I, Thalamas C, Viguerie N, Langin D, Moro C. Endurance exercise training up-regulates lipolytic proteins and reduces triglyceride content in skeletal muscle of obese subjects. J Clin Endocrinol Metab 2013; 98:4863-71. [PMID: 24178794 DOI: 10.1210/jc.2013-2058] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
CONTEXT Skeletal muscle lipase and intramyocellular triglyceride (IMTG) play a role in obesity-related metabolic disorders. OBJECTIVES The aim of the present study was to investigate the impact of 8 weeks of endurance exercise training on IMTG content and lipolytic proteins in obese male subjects. DESIGN AND VOLUNTEERS Ten obese subjects completed an 8-week supervised endurance exercise training intervention in which vastus lateralis muscle biopsy samples were collected before and after training. MAIN OUTCOME MEASURES Clinical characteristics and ex vivo substrate oxidation rates were measured pre- and posttraining. Skeletal muscle lipid content and lipolytic protein expression were also investigated. RESULTS Our data show that exercise training reduced IMTG content by 42% (P < .01) and increased skeletal muscle oxidative capacity, whereas no change in total diacylglycerol content and glucose oxidation was found. Exercise training up-regulated adipose triglyceride lipase, perilipin (PLIN) 3 protein, and PLIN5 protein contents in skeletal muscle despite no change in mRNA levels. Training also increased hormone sensitive-lipase Ser660 phosphorylation. No significant changes in comparative gene identification 58, G₀/G₁ switch gene 2, and PLIN2 protein and mRNA levels were observed in response to training. Interestingly, we noted a strong relationship between skeletal muscle comparative gene identification 58 and mitochondrial respiratory chain complex I protein contents at baseline (r = 0.87, P < .0001). CONCLUSIONS Endurance exercise training coordinately up-regulates fat oxidative capacity and lipolytic protein expression in skeletal muscle of obese subjects. This physiological adaptation probably favors fat oxidation and may alleviate the lipotoxic lipid pressure in skeletal muscle. Enhancement of IMTG turnover may be required for the beneficial metabolic effects of exercise in obesity.
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Affiliation(s)
- Katie Louche
- PhD, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Centre Hospitalier Universitaire Rangueil, BP 84225, 1 Avenue Jean Poulhès, 31432 Toulouse Cedex 4, France.
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23
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Badin PM, Langin D, Moro C. Dynamics of skeletal muscle lipid pools. Trends Endocrinol Metab 2013; 24:607-15. [PMID: 23988586 DOI: 10.1016/j.tem.2013.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 07/22/2013] [Accepted: 08/03/2013] [Indexed: 11/20/2022]
Abstract
Intramyocellular triacylglycerol (IMTG) is emerging as an important energy fuel source during muscle contraction and are adaptively increased in response to exercise, without adverse physiological effects. Paradoxically, elevated IMTG content in obese and type 2 diabetics has been linked to insulin resistance, highlighting the importance of IMTG pools in physiology and pathology. Two separate views suggest that IMTG dynamics are determinant for skeletal muscle fat oxidation, and that disruption of IMTG dynamics facilitates the accumulation of lipotoxic intermediates such as diacylglycerols and ceramides that interfere with insulin signaling. Thus, understanding the factors that control IMTG dynamics is crucial. Here we discuss recent literature describing the regulation of IMTG pools with a particular emphasis on lipases and lipid droplet (LD)-associated proteins.
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Affiliation(s)
- Pierre-Marie Badin
- Obesity Research Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) 1048, Institute of Metabolic and Cardiovascular Diseases (I2MC), Toulouse, France; University of Toulouse, UMR1048, Paul Sabatier University, Toulouse, France
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24
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Fang XB, Zhang LP, Yu XZ, Li JY, Lu CY, Zhao ZH, Yang RJ. Association of HSL gene E1-c.276C>T and E8-c.51C>T mutation with economical traits of Chinese Simmental cattle. Mol Biol Rep 2013; 41:105-12. [DOI: 10.1007/s11033-013-2842-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 10/26/2013] [Indexed: 11/28/2022]
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25
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The role of triglyceride lipases in cancer associated cachexia. Trends Mol Med 2013; 19:292-301. [PMID: 23499576 PMCID: PMC3655383 DOI: 10.1016/j.molmed.2013.02.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 02/15/2013] [Accepted: 02/18/2013] [Indexed: 12/18/2022]
Abstract
Cancer associated cachexia (CAC) is a complex multiorgan syndrome frequently associated with various forms of cancer. Affected patients suffer from a dramatic loss of skeletal muscle and adipose tissue. Most cases are accompanied by anorexia, and nutritional supplements are not sufficient to stop or reverse its course. CAC impairs many forms of therapeutic interventions and accounts for 15-20% of all deaths of cancer patients. Recently, several studies have recognized the importance of lipid metabolism and triglyceride hydrolysis as a major metabolic pathway involved in the initiation and/or progression of CAC. In this review, we explore the contributions of the triglyceride lipases to CAC and discuss various factors modulating lipase activity.
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26
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Gancedo JM. Biological roles of cAMP: variations on a theme in the different kingdoms of life. Biol Rev Camb Philos Soc 2013; 88:645-68. [PMID: 23356492 DOI: 10.1111/brv.12020] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 12/19/2012] [Accepted: 12/20/2012] [Indexed: 12/18/2022]
Abstract
Cyclic AMP (cAMP) plays a key regulatory role in most types of cells; however, the pathways controlled by cAMP may present important differences between organisms and between tissues within a specific organism. Changes in cAMP levels are caused by multiple triggers, most affecting adenylyl cyclases, the enzymes that synthesize cAMP. Adenylyl cyclases form a large and diverse family including soluble forms and others with one or more transmembrane domains. Regulatory mechanisms for the soluble adenylyl cyclases involve either interaction with diverse proteins, as happens in Escherichia coli or yeasts, or with calcium or bicarbonate ions, as occurs in mammalian cells. The transmembrane cyclases can be regulated by a variety of proteins, among which the α subunit and the βγ complex from G proteins coupled to membrane receptors are prominent. cAMP levels also are controlled by the activity of phosphodiesterases, enzymes that hydrolyze cAMP. Phosphodiesterases can be regulated by cAMP, cGMP or calcium-calmodulin or by phosphorylation by different protein kinases. Regulation through cAMP depends on its binding to diverse proteins, its proximal targets, this in turn causing changes in a variety of distal targets. Specifically, binding of cAMP to regulatory subunits of cAMP-dependent protein kinases (PKAs) affects the activity of substrates of PKA, binding to exchange proteins directly activated by cAMP (Epac) regulates small GTPases, binding to transcription factors such as the cAMP receptor protein (CRP) or the virulence factor regulator (Vfr) modifies the rate of transcription of certain genes, while cAMP binding to ion channels modulates their activity directly. Further studies on cAMP signalling will have important implications, not only for advancing fundamental knowledge but also for identifying targets for the development of new therapeutic agents.
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Affiliation(s)
- Juana M Gancedo
- Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Madrid 28029, Spain.
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Than A, Cheng Y, Foh LC, Leow MKS, Lim SC, Chuah YJ, Kang Y, Chen P. Apelin inhibits adipogenesis and lipolysis through distinct molecular pathways. Mol Cell Endocrinol 2012; 362:227-41. [PMID: 22842084 DOI: 10.1016/j.mce.2012.07.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/19/2012] [Accepted: 07/06/2012] [Indexed: 12/30/2022]
Abstract
Apelin is an adipokine secreted by adipocytes. Co-expression of apelin and apelin receptor (APJ) in adipocytes implies the autocrine regulations of apelin on adipocyte functions through yet unknown molecular mechanisms. In the present study, we provide evidence that apelin, through its interaction with APJ receptor, inhibits adipogenesis of pre-adipocytes and lipolysis in mature adipocytes. The detailed molecular pathways underlying apelin signaling is proposed based on our experimental observations. Specifically, we show that apelin suppresses adipogenesis through MAPK kinase/ERK dependent pathways. And by preventing lipid droplet fragmentation, apelin inhibits basal lipolysis through AMP kinase dependent enhancement of perilipin expression and inhibits hormone-stimulated acute lipolysis through decreasing perilipin phosphorylation. Apelin induced decrease of free fatty acid release can be attributed to its dual inhibition on adipogenesis and lipolysis. This study suggests that the autocrine signaling of apelin may serve as a novel therapeutic target for obesity and other metabolic disorders.
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Affiliation(s)
- Aung Than
- Division of Bioengineering, Nanyang Technological University, Singapore 637457, Singapore
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Abstract
Among organelles, lipid droplets (LDs) uniquely constitute a hydrophobic phase in the aqueous environment of the cytosol. Their hydrophobic core of neutral lipids stores metabolic energy and membrane components, making LDs hubs for lipid metabolism. In addition, LDs are implicated in a number of other cellular functions, ranging from protein storage and degradation to viral replication. These processes are functionally linked to many physiological and pathological conditions, including obesity and related metabolic diseases. Despite their important functions and nearly ubiquitous presence in cells, many aspects of LD biology are unknown. In the past few years, the pace of LD investigation has increased, providing new insights. Here, we review the current knowledge of LD cell biology and its translation to physiology.
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Affiliation(s)
- Tobias C Walther
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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Reactive oxygen species facilitate translocation of hormone sensitive lipase to the lipid droplet during lipolysis in human differentiated adipocytes. PLoS One 2012; 7:e34904. [PMID: 22493722 PMCID: PMC3321042 DOI: 10.1371/journal.pone.0034904] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 03/07/2012] [Indexed: 01/18/2023] Open
Abstract
In obesity, there is an increase in reactive oxygen species (ROS) within adipose tissue caused by increases in inflammation and overnutrition. Hormone sensitive lipase (HSL) is part of the canonical lipolytic pathway and critical for complete lipolysis. This study hypothesizes that ROS is a signal that integrates regulation of lipolysis by targeting HSL. Experiments were performed with human differentiated adipocytes from the subcutaneous depot. Antioxidants were employed as a tool to decrease ROS, and it was found that scavenging ROS with diphenyliodonium, N-acetyl cysteine, or resveratrol decreased lipolysis in adipocytes. HSL phosphorylation of a key serine residue, Ser552, as well as translocation of this enzyme from the cytosol to the lipid droplet upon lipolytic stimulation were both abrogated by scavenging ROS. The phosphorylation status of other serine residues on HSL were not affected. These findings are significant because they document that ROS contributes to the physiological regulation of lipolysis via an effect on translocation. Such regulation could be useful in developing new obesity therapies.
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Lucki NC, Li D, Sewer MB. Sphingosine-1-phosphate rapidly increases cortisol biosynthesis and the expression of genes involved in cholesterol uptake and transport in H295R adrenocortical cells. Mol Cell Endocrinol 2012; 348:165-75. [PMID: 21864647 PMCID: PMC3508734 DOI: 10.1016/j.mce.2011.08.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 07/26/2011] [Accepted: 08/03/2011] [Indexed: 12/22/2022]
Abstract
In the acute phase of adrenocortical steroidogenesis, adrenocorticotrophin (ACTH) activates a cAMP/PKA-signaling pathway that promotes the transport of free cholesterol to the inner mitochondrial membrane. We have previously shown that ACTH rapidly stimulates the metabolism of sphingolipids and the secretion of sphingosine-1-phosphate (S1P) in H295R cells. In this study, we examined the effect of S1P on genes involved in the acute phase of steroidogenesis. We show that S1P increases the expression of steroidogenic acute regulatory protein (StAR), 18-kDa translocator protein (TSPO), low-density lipoprotein receptor (LDLR), and scavenger receptor class B type I (SR-BI). S1P-induced StAR mRNA expression requires Gα(i) signaling, phospholipase C (PLC), Ca(2+)/calmodulin-dependent kinase II (CamKII), and ERK1/2 activation. S1P also increases intracellular Ca(2+), the phosphorylation of hormone sensitive lipase (HSL) at Ser(563), and cortisol secretion. Collectively, these findings identify multiple roles for S1P in the regulation of glucocorticoid biosynthesis.
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Affiliation(s)
- Natasha C. Lucki
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332-0230
| | - Donghui Li
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093-0704
| | - Marion B. Sewer
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093-0704
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Ablation of a galectin preferentially expressed in adipocytes increases lipolysis, reduces adiposity, and improves insulin sensitivity in mice. Proc Natl Acad Sci U S A 2011; 108:18696-701. [PMID: 21969596 DOI: 10.1073/pnas.1109065108] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The breakdown of triglycerides, or lipolysis, is a tightly controlled process that regulates fat mobilization in accord with an animal's energy needs. It is well established that lipolysis is stimulated by hormones that signal energy demand and is suppressed by the antilipolytic hormone insulin. However, much still remains to be learned about regulation of lipolysis by intracellular signaling pathways in adipocytes. Here we show that galectin-12, a member of a β-galactoside-binding lectin family preferentially expressed by adipocytes, functions as an intrinsic negative regulator of lipolysis. Galectin-12 is primarily localized on lipid droplets and regulates lipolytic protein kinase A signaling by acting upstream of phosphodiesterase activity to control cAMP levels. Ablation of galectin-12 in mice results in increased adipocyte mitochondrial respiration, reduced adiposity, and ameliorated insulin resistance/glucose intolerance. This study identifies unique properties of this intracellular galectin that is localized to an organelle and performs a critical function in lipid metabolism. These findings add to the significant functions exhibited by intracellular galectins, and have important therapeutic implications for human metabolic disorders.
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Lampidonis AD, Rogdakis E, Voutsinas GE, Stravopodis DJ. The resurgence of Hormone-Sensitive Lipase (HSL) in mammalian lipolysis. Gene 2011; 477:1-11. [PMID: 21241784 DOI: 10.1016/j.gene.2011.01.007] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/22/2010] [Accepted: 01/07/2011] [Indexed: 12/13/2022]
Abstract
The ability to store energy in the form of energy-dense triacylglycerol and to mobilize these stores rapidly during periods of low carbohydrate availability or throughout the strong metabolic demand is a highly conserved process, absolutely essential for survival. In the industrialized world the regulation of this pathway is viewed as an important therapeutic target for disease prevention. Adipose tissue lipolysis is a catabolic process leading to the breakdown of triacylglycerols stored in fat cells, and release of fatty acids and glycerol. Mobilization of adipose tissue fat is mediated by the MGL, HSL and ATGL, similarly functioning enzymes. ATGL initiates lipolysis followed by the actions of HSL on diacylglycerol, and MGL on monoacylglycerol. HSL is regulated by reversible phosphorylation on five critical residues. Phosphorylation alone, however, is not enough to activate HSL. Probably, conformational alterations and a translocation from the cytoplasm to lipid droplets are also involved. In accordance, Perilipin functions as a master regulator of lipolysis, protecting or exposing the triacylglycerol core of a lipid droplet to lipases. The prototype processes of hormonal lipolytic control are the β-adrenergic stimulation and suppression by insulin, both of which affect cytoplasmic cyclic AMP levels. Lipolysis in adipocytes is an important process in the management of body energy reserves. Its deregulation may contribute to the symptoms of type 2 diabetes mellitus and other pathological situations. We, herein, discuss the metabolic regulation and function of lipases mediating mammalian lipolysis with a focus on HSL, quoting newly identified members of the lipolytic proteome.
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Affiliation(s)
- Antonis D Lampidonis
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Zografou, 157 84 Athens, Greece
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Lorente-Cebrián S, Kulyté A, Hedén P, Näslund E, Arner P, Rydén M. Relationship between site-specific HSL phosphorylation and adipocyte lipolysis in obese women. Obes Facts 2011; 4:365-71. [PMID: 22166756 PMCID: PMC6444582 DOI: 10.1159/000334036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND/AIMS In fat cells of obese humans, basal lipolysis is increased but catecholamine-stimulated lipolysis is blunted. This is linked to decreased expression of hormone-sensitive lipase (HSL). Upon stimulation by cAMP, HSL is phosphorylated at several serine residues (P-Ser(552), P-Ser(649) and P-Ser(650)) leading to enzymatic activation. In contrast, P-Ser(554) prevents phosphorylation at Ser(552) and is thus considered an inactivating site. We hypothesized that differences in HSL phosphorylation could be linked to disturbed adipocyte lipolysis in obesity. METHODS Phosphorylation at Ser(552), Ser(554), Ser(650) as well as total HSL and adipose triglyceride lipase (ATGL) protein expression were assessed by Western blot in subcutaneous adipose tissue samples of 32 obese women. Basal and stimulated lipolysis in isolated fat cells were correlated to phosphorylation levels. RESULTS While there was no correlation between basal lipolysis and P-Ser(650) or P-Ser(554), there was a negative correlation with P-Ser(552) (r = 0.39; p < 0.05). In contrast, only P-Ser(554) was strongly and negatively correlated with noradrenaline- (r = -0.50; p < 0.01) and dibutyryl cAMP-stimulated (r = -0.45; p < 0.05) lipolysis. There were no significant correlations between any measure of lipolysis and total levels of HSL and ATGL. CONCLUSION In contrast to total HSL and ATGL levels, phosphorylation at Ser(554) and Ser(552), but not at Ser(650), may differentially predict adipocyte lipolysis in vitro. Posttranslational modifications of HSL may therefore constitute an important regulator of adipocyte lipolysis, at least in adipose tissue of obese women. Whether this is also relevant in lean individuals remains to be demonstrated.
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Affiliation(s)
- Silvia Lorente-Cebrián
- Department of Medicine Huddinge, Lipid Laboratory, Karolinska Institutet, NVS, Karolinska University Hospital, Stockholm, Sweden.
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Kim MH, Park JS, Seo MS, Jung JW, Lee YS, Kang KS. Genistein and daidzein repress adipogenic differentiation of human adipose tissue-derived mesenchymal stem cells via Wnt/β-catenin signalling or lipolysis. Cell Prolif 2010; 43:594-605. [PMID: 21039998 DOI: 10.1111/j.1365-2184.2010.00709.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES One aspect of the effects of isoflavones against fat deposition might be at least associated with the mechanism by which Wnt/β-catenin signalling inhibits adipocyte differentiation. However, it remains completely unknown as to whether isoflavones might influence Wnt signalling during commitment of pluripotent mesenchymal stem cells (MSCs) to adipose lineages. In the present study, we have investigated the mechanisms underlying effects of genistein and daidzein, the major soy isoflavones, on anti-adipogenic Wnt/β-catenin signalling. MATERIALS AND METHODS Adipose tissue-derived (AD) MSCs were exposed continuously to genistein and daidzein (0.01-100 μm) during adipogenic differentiation (21 days). An oestrogen antagonist, ICI 182,780, was used to determine whether or not the isoflavones activated Wnt signalling via oestrogen receptors (ERs). RESULTS Genistein and daidzein suppressed adipogenic differentiation of AD-MSCs in a dose-dependent manner and inhibited expression of adipogenic markers, PPARγ, SREBP-1c and Glut 4, from mid-phase differentiation. Microarrays showed that anti-adipogenic effects of genistein were principally attributable to activation of Wnt signalling via ERs-dependent pathway, such as Erk/JNK signalling and LEF/TCF4 co-activators. These findings were supported by evidence that the effects of genistein were offset by ICI182,780. Unlike genistein, daidzein inhibited adipogenesis through stimulation of lipolysis, with for example, PKA-mediated hormone sensitive lipase. This is consistent with the increase in glycerol released from AD-MSCs. In conclusion, understanding that different sets of mechanisms of the two isoflavones on adipogenesis will help the design of novel strategies to prevent observed current epidemic levels of obesity, using isoflavones.
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Affiliation(s)
- M-H Kim
- Department of Food and Nutrition, Seoul National University, Seoul, Korea
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Lass A, Zimmermann R, Oberer M, Zechner R. Lipolysis - a highly regulated multi-enzyme complex mediates the catabolism of cellular fat stores. Prog Lipid Res 2010; 50:14-27. [PMID: 21087632 PMCID: PMC3031774 DOI: 10.1016/j.plipres.2010.10.004] [Citation(s) in RCA: 454] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 12/17/2022]
Abstract
Lipolysis is the biochemical pathway responsible for the catabolism of triacylglycerol (TAG) stored in cellular lipid droplets. The hydrolytic cleavage of TAG generates non-esterified fatty acids, which are subsequently used as energy substrates, essential precursors for lipid and membrane synthesis, or mediators in cell signaling processes. Consistent with its central importance in lipid and energy homeostasis, lipolysis occurs in essentially all tissues and cell types, it is most abundant, however, in white and brown adipose tissue. Over the last 5years, important enzymes and regulatory protein factors involved in lipolysis have been identified. These include an essential TAG hydrolase named adipose triglyceride lipase (ATGL) [annotated as patatin-like phospholipase domain-containing protein A2], the ATGL activator comparative gene identification-58 [annotated as α/β hydrolase containing protein 5], and the ATGL inhibitor G0/G1 switch gene 2. Together with the established hormone-sensitive lipase [annotated as lipase E] and monoglyceride lipase, these proteins constitute the basic "lipolytic machinery". Additionally, a large number of hormonal signaling pathways and lipid droplet-associated protein factors regulate substrate access and the activity of the "lipolysome". This review summarizes the current knowledge concerning the enzymes and regulatory processes governing lipolysis of fat stores in adipose and non-adipose tissues. Special emphasis will be given to ATGL, its regulation, and physiological function.
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Affiliation(s)
- Achim Lass
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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36
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Stenson BM, Rydén M, Venteclef N, Dahlman I, Pettersson AML, Mairal A, Aström G, Blomqvist L, Wang V, Jocken JWE, Clément K, Langin D, Arner P, Laurencikiene J. Liver X receptor (LXR) regulates human adipocyte lipolysis. J Biol Chem 2010; 286:370-9. [PMID: 21030586 DOI: 10.1074/jbc.m110.179499] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Liver X receptor (LXR) is an important regulator of carbohydrate and lipid metabolism in humans and mice. We have recently shown that activation of LXR regulates cellular fuel utilization in adipocytes. In contrast, the role of LXR in human adipocyte lipolysis, the major function of human white fat cells, is not clear. In the present study, we stimulated in vitro differentiated human and murine adipocytes with the LXR agonist GW3965 and observed an increase in basal lipolysis. Microarray analysis of human adipocyte mRNA following LXR activation revealed an altered gene expression of several lipolysis-regulating proteins, which was also confirmed by quantitative real-time PCR. We show that expression and intracellular localization of perilipin1 (PLIN1) and hormone-sensitive lipase (HSL) are affected by GW3965. Although LXR activation does not influence phosphorylation status of HSL, HSL activity is required for the lipolytic effect of GW3965. This effect is abolished by PLIN1 knockdown. In addition, we demonstrate that upon activation, LXR binds to the proximal regions of the PLIN1 and HSL promoters. By selective knock-down of either LXR isoform, we show that LXRα is the major isoform mediating the lipolysis-related effects of LXR. In conclusion, the present study demonstrates that activation of LXRα up-regulates basal human adipocyte lipolysis. This is at least partially mediated through LXR binding to the PLIN1 promoter and down-regulation of PLIN1 expression.
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Affiliation(s)
- Britta M Stenson
- Department of Medicine, Karolinska Institutet, Huddinge, S-14186, Sweden
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Abstract
PURPOSE OF REVIEW Adipose tissue lipolysis is a critical pathway for the maintenance of energy homeostasis through the degradation of triglycerides and the release of fatty acids into the circulation. The understanding of the cellular factors regulating triglyceride hydrolysis and the metabolic function of lipases has considerably expanded in the last few years, revealing an unexpected complexity. This review aims at describing recent discoveries related to the lipolytic pathway and its regulatory mechanisms. RECENT FINDINGS Considerable progress has been made in understanding the role and the mechanisms of activation of the lipolytic enzymes. Recent discoveries have dramatically altered the view of adipose tissue lipolysis and highlighted the importance of additional molecular actors in regulating this process. Catecholamines, natriuretic peptides, and insulin are considered to be the major regulators of lipolysis in humans. However, autocrine/paracrine factors such as metabolites and prostaglandins may also participate in its regulation. SUMMARY The manipulation of lipolysis has therapeutic potential in the metabolic disorders frequently associated with obesity. Unraveling the molecular events occurring during regulation of lipolysis may lead to novel therapeutic targets.
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Affiliation(s)
- Catherine-Ines Kolditz
- Inserm, Unité 858, Obesity Research Laboratory, Rangueil Institute of Molecular Medicine (I2MR), IFR150, Toulouse, France
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Krintel C, Klint C, Lindvall H, Mörgelin M, Holm C. Quarternary structure and enzymological properties of the different hormone-sensitive lipase (HSL) isoforms. PLoS One 2010; 5:e11193. [PMID: 20567594 PMCID: PMC2887374 DOI: 10.1371/journal.pone.0011193] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 05/26/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of energy in the form of fatty acids from intracellular stores of neutral lipids. The enzyme has been shown to exist in different isoforms with different molecular masses (84 kDa, 89 kDa and 117 kDa) expressed in a tissue-dependent manner, where the predominant 84 kDa form in adipocytes is the most extensively studied. METHODOLOGY/PRINCIPAL FINDINGS In this study we employed negative stain electron microscopy (EM) to analyze the quarternary structure of the different HSL isoforms. The results show that all three isoforms adopt a head-to-head homodimeric organization, where each monomer contains two structural domains. We also used enzymatic assays to show that despite the variation in the size of the N-terminal domain all three isoforms exhibit similar enzymological properties with regard to psychrotolerance and protein kinase A (PKA)-mediated phosphorylation and activation. CONCLUSIONS/SIGNIFICANCE We present the first data on the quaternary structure and domain organization of the three HSL isoforms. We conclude that despite large differences in the size of the N-terminal, non-catalytic domain all three HSL isoforms exhibit the same three-dimensional architecture. Furthermore, the three HSL isoforms are very similar with regard to two unique enzymological characteristics of HSL, i.e., cold adaptation and PKA-mediated activation.
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Affiliation(s)
- Christian Krintel
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Division of Diabetes, Metabolism and Endocrinology, Department of Molecular Biophysics, Lund University, Lund, Sweden
| | - Cecilia Klint
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Håkan Lindvall
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Matthias Mörgelin
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Cecilia Holm
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail:
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Enhanced MALDI-TOF MS analysis of phosphopeptides using an optimized DHAP/DAHC matrix. J Biomed Biotechnol 2010; 2010:759690. [PMID: 20339515 PMCID: PMC2842900 DOI: 10.1155/2010/759690] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 09/11/2009] [Accepted: 12/31/2009] [Indexed: 11/17/2022] Open
Abstract
Selecting an appropriate matrix solution is one of the most effective means of increasing the ionization efficiency of phosphopeptides in matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In this study, we systematically assessed matrix combinations of 2, 6-dihydroxyacetophenone (DHAP) and diammonium hydrogen citrate (DAHC), and demonstrated that the low ratio DHAP/DAHC matrix was more effective in enhancing the ionization of phosphopeptides. Low femtomole level of phosphopeptides from the tryptic digests of α-casein and β-casein was readily detected by MALDI-TOF-MS in both positive and negative ion mode without desalination or phosphopeptide enrichment. Compared with the DHB/PA matrix, the optimized DHAP/DAHC matrix yielded superior sample homogeneity and higher phosphopeptide measurement sensitivity, particularly when multiple phosphorylated peptides were assessed. Finally, the DHAP/DAHC matrix was applied to identify phosphorylation sites from α-casein and β-casein and to characterize two phosphorylation sites from the human histone H1 treated with Cyclin-Dependent Kinase-1 (CDK1) by MALDI-TOF/TOF MS.
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Wang H, Hu L, Dalen K, Dorward H, Marcinkiewicz A, Russell D, Gong D, Londos C, Yamaguchi T, Holm C, Rizzo MA, Brasaemle D, Sztalryd C. Activation of hormone-sensitive lipase requires two steps, protein phosphorylation and binding to the PAT-1 domain of lipid droplet coat proteins. J Biol Chem 2009; 284:32116-25. [PMID: 19717842 PMCID: PMC2797282 DOI: 10.1074/jbc.m109.006726] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 08/27/2009] [Indexed: 11/06/2022] Open
Abstract
Lipolysis is an important metabolic pathway controlling energy homeostasis through degradation of triglycerides stored in lipid droplets and release of fatty acids. Lipid droplets of mammalian cells are coated with one or more members of the PAT protein family, which serve important functions in regulating lipolysis. In this study, we investigate the mechanisms by which PAT family members, perilipin A, adipose differentiation-related protein (ADFP), and LSDP5, control lipolysis catalyzed by hormone-sensitive lipase (HSL), a major lipase in adipocytes and several non-adipose cells. We applied fluorescence microscopic tools to analyze proteins in situ in cultured Chinese hamster ovary cells using fluorescence recovery after photobleaching and anisotropy Forster resonance energy transfer. Fluorescence recovery after photobleaching data show that ADFP and LSDP5 exchange between lipid droplet and cytoplasmic pools, whereas perilipin A does not. Differences in protein mobility do not correlate with PAT protein-mediated control of lipolysis catalyzed by HSL or endogenous lipases. Forster resonance energy transfer and co-immunoprecipitation experiments reveal that each of the three PAT proteins bind HSL through interaction of the lipase with amino acids within the highly conserved amino-terminal PAT-1 domain. ADFP and LSDP5 bind HSL under basal conditions, whereas phosphorylation of serine residues within three amino-terminal protein kinase A consensus sequences of perilipin A is required for HSL binding and maximal lipolysis. Finally, protein kinase A-mediated phosphorylation of HSL increases lipolysis in cells expressing ADFP or LSDP5; in contrast, phosphorylation of perilipin A exerts the major control over HSL-mediated lipolysis when perilipin is the main lipid droplet protein.
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Affiliation(s)
- Hong Wang
- From the Geriatric Research, Education, and Clinical Center, Baltimore Veterans Affairs Health Care Center, and Division of Endocrinology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Liping Hu
- From the Geriatric Research, Education, and Clinical Center, Baltimore Veterans Affairs Health Care Center, and Division of Endocrinology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Knut Dalen
- the Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-8028
| | - Heidi Dorward
- the Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-8028
| | - Amy Marcinkiewicz
- the Department of Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901
| | - Deanna Russell
- the Department of Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901
| | - Dawei Gong
- the Division of Endocrinology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Constantine Londos
- the Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-8028
| | - Tomohiro Yamaguchi
- the Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan
| | - Cecilia Holm
- the Department of Experimental Medical Science, Lund University, BMC C11, SE-221 84, Lund, Sweden
| | - Mark A. Rizzo
- the Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Dawn Brasaemle
- the Department of Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901
| | - Carole Sztalryd
- From the Geriatric Research, Education, and Clinical Center, Baltimore Veterans Affairs Health Care Center, and Division of Endocrinology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201
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Abstract
Human obesity and its complications are an increasing burden in developed and underdeveloped countries. Adipose tissue mass and the mechanisms that control it are central to elucidating the aetiology of obesity and insulin resistance. Over the past 15 years tremendous progress has been made in several avenues relating to adipose tissue. Knowledge of the lipolytic machinery has grown with the identification of new lipases, cofactors and interactions between proteins and lipids that are central to the regulation of basal and stimulated lipolysis. The dated idea of an inert lipid droplet has been appropriately revamped to that of a dynamic and highly-structured organelle that in itself offers regulatory control over lipolysis. The present review provides an overview of the numerous partners and pathways involved in adipose tissue lipolysis and their interaction under various metabolic states. Integration of these findings into whole adipose tissue metabolism and its systemic effects is also presented in the context of inflammation and insulin resistance.
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Duncan RE, Wang Y, Ahmadian M, Lu J, Sarkadi-Nagy E, Sul HS. Characterization of desnutrin functional domains: critical residues for triacylglycerol hydrolysis in cultured cells. J Lipid Res 2009; 51:309-17. [PMID: 19692632 DOI: 10.1194/jlr.m000729] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Murine desnutrin/human ATGL is a triacylglycerol (TAG) hydrolase with a predicted catalytic dyad within an alpha-beta hydrolase fold in the N-terminal region. In humans, mutations resulting in C-terminal truncation cause neutral lipid storage disease with myopathy. To identify critical functional domains, we measured TAG breakdown in cultured cells by mutated or truncated desnutrin. In vitro, C-terminally truncated desnutrin displayed an even higher apparent V(max) than the full-length form without changes in K(m), which may be explained by our finding of an interaction between the C- and N-terminal domains. In live cells, however, C-terminally truncated adenoviral desnutrin had lower TAG hydrolase activity. We investigated a role for the phosphorylation of C-terminal S406 and S430 residues but found that these were not necessary for TAG breakdown or lipid droplet localization in cells. The predicted N-terminal active sites, S47 and D166, were both critical for TAG hydrolysis in live cells and in vitro. We also identified two overlapping N-terminal motifs that predict lipid substrate binding domains, a glycine-rich motif (underlined) and an amphipathic alpha-helix (bold) within amino acid residues 10-24 (ISFAGCGFLGVYHIG). G14, F17, L18, and V20, but not G16 and G19, were important for TAG hydrolysis, suggesting a potential role for the amphipathic alpha-helix in TAG binding. This study identifies for the first time critical sites in the N-terminal region of desnutrin and reveals the requirement of the C-terminal region for TAG hydrolysis in cultured cells.
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Affiliation(s)
- Robin E Duncan
- Department of Nutritional Science and Toxicology, University of California, Berkeley, CA 94720, USA
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Krintel C, Mörgelin M, Logan DT, Holm C. Phosphorylation of hormone-sensitive lipase by protein kinase A in vitro promotes an increase in its hydrophobic surface area. FEBS J 2009; 276:4752-62. [PMID: 19664063 DOI: 10.1111/j.1742-4658.2009.07172.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hormone-sensitive lipase (EC 3.1.1.79; HSL) is a key enzyme in the mobilization of fatty acids from stored triacylglycerols. HSL activity is controlled by phosphorylation of at least four serines. In rat HSL, Ser563, Ser659 and Ser660 are phosphorylated by protein kinase A (PKA) in vitro as well as in vivo, and Ser660 and Ser659 have been shown to be the activity-controlling sites in vitro. The exact molecular events of PKA-mediated activation of HSL in vitro are yet to be determined, but increases in both Vmax and S0.5 seem to be involved, as recently shown for human HSL. In this study, the hydrophobic fluorescent probe 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) was found to inhibit the hydrolysis of triolein by purified recombinant rat adipocyte HSL, with a decrease in the effect of bis-ANS upon PKA phosphorylation of HSL. The interaction of HSL with bis-ANS was found to have a Kd of 1 microM in binding assays. Upon PKA phosphorylation, the interactions of HSL with both bis-ANS and the alternative probe SYPRO Orange were increased. By negative stain transmission electron microscopy, phosphorylated HSL was found to have a closer interaction with phospholipid vesicles than unphosphorylated HSL. Taken together, our results show that HSL increases its hydrophobic nature upon phosphorylation by PKA. This suggests that PKA phosphorylation induces a conformational change that increases the exposed hydrophobic surface and thereby facilitates binding of HSL to the lipid substrate.
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Affiliation(s)
- Christian Krintel
- Department of Experimental Medical Science, Division of Diabetes, Metabolism and Endocrinology, Lund University, Sweden
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