1
|
Cinti S. Obese Adipocytes Have Altered Redox Homeostasis with Metabolic Consequences. Antioxidants (Basel) 2023; 12:1449. [PMID: 37507987 PMCID: PMC10376822 DOI: 10.3390/antiox12071449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
White and brown adipose tissues are organized to form a real organ, the adipose organ, in mice and humans. White adipocytes of obese animals and humans are hypertrophic. This condition is accompanied by a series of organelle alterations and stress of the endoplasmic reticulum. This stress is mainly due to reactive oxygen species activity and accumulation, lending to NLRP3 inflammasome activation. This last causes death of adipocytes by pyroptosis and the formation of large cellular debris that must be removed by macrophages. During their chronic scavenging activity, macrophages produce several secretory products that have collateral consequences, including interference with insulin receptor activity, causing insulin resistance. The latter is accompanied by an increased noradrenergic inhibitory innervation of Langerhans islets with de-differentiation of beta cells and type 2 diabetes. The whitening of brown adipocytes could explain the different critical death size of visceral adipocytes and offer an explanation for the worse clinical consequence of visceral fat accumulation. White to brown transdifferentiation has been proven in mice and humans. Considering the energy-dispersing activity of brown adipose tissue, transdifferentiation opens new therapeutic perspectives for obesity and related disorders.
Collapse
Affiliation(s)
- Saverio Cinti
- Scientific Director Centre of Obesity, Marche Polytechnic University, Via Tronto 10a, 60126 Ancona, Italy
| |
Collapse
|
2
|
Prentice KJ, Lee A, Cedillo P, Inouye KE, Ertunc ME, Riveros JK, Lee GY, Hotamisligil GS. Sympathetic tone dictates the impact of lipolysis on FABP4 secretion. J Lipid Res 2023; 64:100386. [PMID: 37172691 PMCID: PMC10248869 DOI: 10.1016/j.jlr.2023.100386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 04/19/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Levels of circulating fatty acid binding protein 4 (FABP4) protein are strongly associated with obesity and metabolic disease in both mice and humans, and secretion is stimulated by β-adrenergic stimulation both in vivo and in vitro. Previously, lipolysis-induced FABP4 secretion was found to be significantly reduced upon pharmacological inhibition of adipose triglyceride lipase (ATGL) and was absent from adipose tissue explants from mice specifically lacking ATGL in their adipocytes (ATGLAdpKO). Here, we find that upon activation of β-adrenergic receptors in vivo, ATGLAdpKO mice unexpectedly exhibited significantly higher levels of circulating FABP4 as compared with ATGLfl/fl controls, despite no corresponding induction of lipolysis. We generated an additional model with adipocyte-specific deletion of both FABP4 and ATGL (ATGL/FABP4AdpKO) to evaluate the cellular source of this circulating FABP4. In these animals, there was no evidence of lipolysis-induced FABP4 secretion, indicating that the source of elevated FABP4 levels in ATGLAdpKO mice was indeed from the adipocytes. ATGLAdpKO mice exhibited significantly elevated corticosterone levels, which positively correlated with plasma FABP4 levels. Pharmacological inhibition of sympathetic signaling during lipolysis using hexamethonium or housing mice at thermoneutrality to chronically reduce sympathetic tone significantly reduced FABP4 secretion in ATGLAdpKO mice compared with controls. Therefore, activity of a key enzymatic step of lipolysis mediated by ATGL, per se, is not required for in vivo stimulation of FABP4 secretion from adipocytes, which can be induced through sympathetic signaling.
Collapse
Affiliation(s)
- Kacey J Prentice
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Alexandra Lee
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Paulina Cedillo
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Karen E Inouye
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Meric Erikci Ertunc
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Jillian K Riveros
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Grace Yankun Lee
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Gökhan S Hotamisligil
- Department of Molecular Metabolism; Sabri Ülker Center for Metabolic Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA.
| |
Collapse
|
3
|
Yuksel S, Aredo B, Zegeye Y, Zhao CX, Tang M, Li X, Hulleman JD, Gautron L, Ludwig S, Moresco EMY, Butovich IA, Beutler BA, Ufret-Vincenty RL. Forward genetic screening using fundus spot scale identifies an essential role for Lipe in murine retinal homeostasis. Commun Biol 2023; 6:533. [PMID: 37198396 DOI: 10.1038/s42003-023-04870-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 04/24/2023] [Indexed: 05/19/2023] Open
Abstract
Microglia play a role in the pathogenesis of many retinal diseases. Fundus spots in mice often correlate with the accumulation of activated subretinal microglia. Here we use a semiquantitative fundus spot scoring scale in combination with an unbiased, state-of-the-science forward genetics pipeline to identify causative associations between chemically induced mutations and fundus spot phenotypes. Among several associations, we focus on a missense mutation in Lipe linked to an increase in yellow fundus spots in C57BL/6J mice. Lipe-/- mice generated using CRISPR-Cas9 technology are found to develop accumulation of subretinal microglia, a retinal degeneration with decreased visual function, and an abnormal retinal lipid profile. We establish an indispensable role of Lipe in retinal/RPE lipid homeostasis and retinal health. Further studies using this new model will be aimed at determining how lipid dysregulation results in the activation of subretinal microglia and whether these microglia also play a role in the subsequent retinal degeneration.
Collapse
Affiliation(s)
- Seher Yuksel
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bogale Aredo
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yeshumenesh Zegeye
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Cynthia X Zhao
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Miao Tang
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaohong Li
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John D Hulleman
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Laurent Gautron
- Center for Hypothalamic Research and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sara Ludwig
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eva M Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Igor A Butovich
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA.
| | - Bruce A Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | | |
Collapse
|
4
|
The anxiolytic drug opipramol inhibits insulin-induced lipogenesis in fat cells and insulin secretion in pancreatic islets. J Physiol Biochem 2023:10.1007/s13105-023-00950-8. [PMID: 36821072 DOI: 10.1007/s13105-023-00950-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 02/09/2023] [Indexed: 02/24/2023]
Abstract
The antidepressant drug opipramol has been reported to exert antilipolytic effect in human adipocytes, suggesting that alongside its neuropharmacological properties, this agent might modulate lipid utilization by peripheral tissues. However, patients treated for depression or anxiety disorders by this tricyclic compound do not exhibit the body weight gain or the glucose tolerance alterations observed with various other antidepressant or antipsychotic agents such as amitriptyline and olanzapine, respectively. To examine whether opipramol reproduces or impairs other actions of insulin, its direct effects on glucose transport, lipogenesis and lipolysis were investigated in adipocytes while its influence on insulin secretion was studied in pancreatic islets. In mouse and rat adipocytes, opipramol did not activate triglyceride breakdown, but partially inhibited the lipolytic action of isoprenaline or forskolin, especially in the 10-100 μM range. At 100 μM, opipramol also inhibited the glucose incorporation into lipids without limiting the glucose transport in mouse adipocytes. In pancreatic islets, opipramol acutely impaired the stimulation of insulin secretion by various activators (high glucose, high potassium, forskolin...). Similar inhibitory effects were observed in mouse and rat pancreatic islets and were reproduced with 100 μM haloperidol, in a manner that was independent from alpha2-adrenoceptor activation but sensitive to Ca2+ release. All these results indicated that the anxiolytic drug opipramol is not only active in central nervous system but also in multiple peripheral tissues and endocrine organs. Due to its capacity to modulate the lipid and carbohydrate metabolisms, opipramol deserves further studies in order to explore its therapeutic potential for the treatment of obese and diabetic states.
Collapse
|
5
|
Khazaal AQ, Haque N, Krager CR, Krager SL, Chambers C, Wilber A, Tischkau SA. Aryl hydrocarbon receptor affects circadian-regulated lipolysis through an E-Box-dependent mechanism. Mol Cell Endocrinol 2023; 559:111809. [PMID: 36283500 PMCID: PMC10509633 DOI: 10.1016/j.mce.2022.111809] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022]
Abstract
An internal circadian clock regulates timing of systemic energy homeostasis. The central clock in the hypothalamic suprachiasmatic nucleus (SCN) directs local clocks in peripheral tissues such as liver, muscle, and adipose tissue to synchronize metabolism with food intake and rest/activity cycles. Aryl hydrocarbon receptor (AhR) interacts with the molecular circadian clockworks. Activation of AhR dampens rhythmic expression of core clock genes, which may lead to metabolic dysfunction. Given the importance of appropriately-timed adipose tissue function to regulation of energy homeostasis, this study focused on mechanisms by which AhR may influence clock-controlled adipose tissue activity. We hypothesized that AhR activation in adipose tissue would impair lipolysis by dampening adipose rhythms, leading to a decreased lipolysis rate during fasting, and subsequently, altered serum glucose concentrations. Levels of clock gene and lipolysis gene transcripts in mouse mesenchymal stem cells (BMSCs) differentiated into mature adipocytes were suppressed by the AhR agonist β-napthoflavone (BNF), in an AhR dependent manner. BNF altered rhythms of core clock gene and lipolysis gene transcripts in C57bl6/J mice. BNF reduced serum free fatty acids, glycerol and liver glycogen. Chromatin immunoprecipitation indicated that BNF increased binding of AhR to E-Box elements in clock gene and lipolysis gene promoters. These data establish a link between AhR activation and impaired lipolysis, specifically by altering adipose tissue rhythmicity. In response to the decreased available energy from impaired lipolysis, the body increases glycogenolysis, thereby degrading more glycogen to provide necessary energy.
Collapse
Affiliation(s)
- Ali Qasim Khazaal
- Biotechnology Department, College of Science, University of Baghdad, Baghdad, Iraq; Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Nazmul Haque
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Callie R Krager
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Stacey L Krager
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Christopher Chambers
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Andrew Wilber
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Shelley A Tischkau
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA; Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA.
| |
Collapse
|
6
|
Liang M, Ma L, Li X, Feng D, Zhang J, Sun Y. Identification and characterization of two types of triacylglycerol lipase genes from Neocaridina denticulata sinensis. FISH & SHELLFISH IMMUNOLOGY 2022; 131:980-990. [PMID: 36379446 DOI: 10.1016/j.fsi.2022.11.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 06/16/2023]
Abstract
Triacylglycerol lipases (TGLs) can catalyze the hydrolysis reaction of triacylglycerol serving multiple functions in most organisms. Based on the genomic and transcriptomic databases of Neocaridina denticulata sinensis, two TGL genes from N. denticulata sinensis designated NdTGL1 and NdTGL2 were identified and characterized. NdTGL1 showed the highest expression in the stomach, followed by the testis and hepatopancreas, and NdTGL2 exhibited the maximum expression in the hepatopancreas, followed by the stomach and heart. Under the stimulation of copper ion, the expression of NdTGL1 peaked at 12 h and the expression of NdTGL2 elevated significantly at 24 h after stimulation (P < 0.05). It is speculated that NdTGLs may play an important role in the stress response of N. denticulata sinensis. Challenged with Vibrio parahaemolyticus, the expression profiles of NdTGL1 and NdTGL2 in the hepatopancreas was different, which indicates that the immune response of the V. parahaemolyticus challenge might lead to changes in triglyceride metabolism. The recombinant NdTGL (recNdTGL1 and recNdTGL2) were obtained and the enzymatic characterization of recNdTGL1 and recNdTGL2 were determined. The common maximum activity and stability of the recNdTGL1 and recNdTGL2 were observed at 45 °C and 10 °C, respectively. Both recNdTGL1 and recNdTGL2 exhibited the highest activity at pH 10.0. Furthermore, the recNdTGL1 and recNdTGL2 displayed the maximum stability at pH 5.0 and pH 8.0, respectively. In presence of different metal ions, the enzyme activity of recNdTGL1 and recNdTGL2 were inhibited by Cu2+ and Zn2+, and decreased by about 25%. Studies on the triacylglycerol lipases of N. denticulata sinensis provide theoretical support for studies related to fat metabolism in crustaceans and studies on response mechanism of digestive enzymes to microbial pathogens.
Collapse
Affiliation(s)
- Meiling Liang
- School of Life Sciences, Institute of Life Sciences and Green Development, Engineering Laboratory of Microbial Breeding and Preservation of Hebei Province, Hebei University, Baoding, 071002, China; Key Laboratory of Microbial Diversity Research and Application of Hebei Province, Hebei University, Baoding, 071002, China
| | - Liya Ma
- School of Life Sciences, Institute of Life Sciences and Green Development, Engineering Laboratory of Microbial Breeding and Preservation of Hebei Province, Hebei University, Baoding, 071002, China
| | - Xin Li
- School of Life Sciences, Institute of Life Sciences and Green Development, Engineering Laboratory of Microbial Breeding and Preservation of Hebei Province, Hebei University, Baoding, 071002, China
| | - Dandan Feng
- School of Life Sciences, Institute of Life Sciences and Green Development, Engineering Laboratory of Microbial Breeding and Preservation of Hebei Province, Hebei University, Baoding, 071002, China
| | - Jiquan Zhang
- School of Life Sciences, Institute of Life Sciences and Green Development, Engineering Laboratory of Microbial Breeding and Preservation of Hebei Province, Hebei University, Baoding, 071002, China.
| | - Yuying Sun
- School of Life Sciences, Institute of Life Sciences and Green Development, Engineering Laboratory of Microbial Breeding and Preservation of Hebei Province, Hebei University, Baoding, 071002, China; Key Laboratory of Microbial Diversity Research and Application of Hebei Province, Hebei University, Baoding, 071002, China.
| |
Collapse
|
7
|
Fischer AW, Jaeckstein MY, Heeren J. Lysosomal acid lipase promotes endothelial proliferation in cold-activated adipose tissue. Adipocyte 2022; 11:28-33. [PMID: 34957913 PMCID: PMC8726628 DOI: 10.1080/21623945.2021.2013416] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Oxidative tissues such as brown adipose tissue and muscle internalize large amounts of circulating lipids and glucose as energy source. Endothelial cells (ECs) provide a platform for regulated transport and processing of blood-borne nutrients. Next to this role, it has become recognized that intercellular crosstalk between ECs and underlying parenchymal cells is indispensable for maintenance of tissue homoeostasis. Here, we comment on our recent observation that capillary ECs in thermogenic adipose tissues take up and metabolize entire triglyceride-rich lipoprotein (TRL) particles in response to cold exposure. This process is dependent on CD36, lipoprotein lipase (LPL) and lysosomal acid lipase (LAL). Remarkably, loss of LAL specifically in endothelial cells results in impaired endothelial proliferation and diminished thermogenic adaptation. Mechanistically, cell culture experiments indicate that LAL-mediated TRL processing leads to the generation of reactive oxygen species, which in turn activate hypoxia-induced factor (HIF)-mediated proliferative responses. In the current manuscript, we provide in vivo evidence that LAL-deficiency impairs proliferation of endothelial cells in thermogenic adipose tissue. In addition, we show uptake of nanoparticle-labelled TRL and LAL expression in cardiac endothelial cells, suggesting a physiological function of endothelial lipoprotein processing not only in thermogenic adipose tissue but also in cardiac muscle.
Collapse
Affiliation(s)
- Alexander W. Fischer
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michelle Y. Jaeckstein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
8
|
Muller YL, Sutherland J, Nair AK, Koroglu C, Kobes S, Knowler WC, Van Hout CV, Shuldiner AR, Hanson RL, Bogardus C, Baier LJ. A missense variant Arg611Cys in LIPE which encodes hormone sensitive lipase decreases lipolysis and increases risk of type 2 diabetes in American Indians. Diabetes Metab Res Rev 2022; 38:e3504. [PMID: 34655148 DOI: 10.1002/dmrr.3504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 10/09/2021] [Indexed: 11/08/2022]
Abstract
AIMS Hormone sensitive lipase (HSL), encoded by the LIPE gene, is involved in lipolysis. Based on prior animal and human studies, LIPE was analysed as a candidate gene for the development of type 2 diabetes (T2D) in a community-based sample of American Indians. MATERIALS AND METHODS Whole-exome sequence data from 6782 participants with longitudinal clinical measures were used to identify variation in LIPE. RESULTS Amongst the 16 missense variants identified, an Arg611Cys variant (rs34052647; Cys-allele frequency = 0.087) significantly associated with T2D (OR [95% CI] = 1.38 [1.17-1.64], p = 0.0002, adjusted for age, sex, birth year, and the first five genetic principal components) and an earlier onset age of T2D (HR = 1.22 [1.09-1.36], p = 0.0005). This variant was further analysed for quantitative traits related to T2D. Amongst non-diabetic American Indians, those with the T2D risk Cys-allele had increased insulin levels during an oral glucose tolerance test (0.07 SD per Cys-allele, p = 0.04) and a mixed meal test (0.08 log10 µU/ml per Cys-allele, p = 0.003), and had increased lipid oxidation rates post-absorptively and during insulin infusion (0.07 mg [kg estimated metabolic body size {EMBS}]-1 min-1 per Cys-allele for both, p = 0.01 and 0.009, respectively), compared to individuals with the non-risk Arg-allele. In vitro functional studies showed that cells expressing the Cys-allele had a 17.2% decrease in lipolysis under isoproterenol stimulation (p = 0.03) and a 21.3% decrease in lipase enzyme activity measured by using p-nitrophenyl butyrate as a substrate (p = 0.04) compared to the Arg-allele. CONCLUSION The Arg611Cys variant causes a modest impairment in lipolysis, thereby affecting glucose homoeostasis and risk of T2D.
Collapse
Affiliation(s)
- Yunhua L Muller
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | - Jeff Sutherland
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | - Anup K Nair
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | - Cigdem Koroglu
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | - Sayuko Kobes
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | - William C Knowler
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | | | - Alan R Shuldiner
- Regeneron Genetics Centre, Regeneron Pharmaceuticals, Tarrytown, New York, USA
| | - Robert L Hanson
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | - Clifton Bogardus
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| | - Leslie J Baier
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA
| |
Collapse
|
9
|
Boone-Villa D, Ventura-Sobrevilla J, Aguilera-Méndez A, Jiménez-Villarreal J. The effect of adenosine monophosphate-activated protein kinase on lipolysis in adipose tissue: an historical and comprehensive review. Arch Physiol Biochem 2022; 128:7-23. [PMID: 35143739 DOI: 10.1080/13813455.2019.1661495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
CONTEXT Lipolysis is one of the most important pathways for energy management, its control in the adipose tissue (AT) is a potential therapeutic target for metabolic diseases. Adenosine Mono Phosphate-activated Protein Kinase (AMPK) is a key regulatory enzyme in lipids metabolism and a potential target for diabetes and obesity treatment. OBJECTIVE The aim of this work is to analyse the existing information on the relationship of AMPK and lipolysis in the AT. METHODS A thorough search of bibliography was performed in the databases Scopus and Web of Knowledge using the terms lipolysis, adipose tissue, and AMPK, the unrelated publications were excluded, and the documents were analysed. RESULTS Sixty-three works were found and classified in 3 categories: inhibitory effects, stimulatory effect, and diverse relationships; remarkably, the newest researches support an upregulating relationship of AMPK over lipolysis. CONCLUSION The most probable reality is that the relationship AMPK-lipolysis depends on the experimental conditions.
Collapse
Affiliation(s)
- Daniel Boone-Villa
- School of Medicine Northern Unit, Universidad Autonoma de Coahuila, Piedras Negras, México
| | | | - Asdrúbal Aguilera-Méndez
- Institute of Biological Chemistry Research, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, México
| | | |
Collapse
|
10
|
Levine JA, Sarrafan-Chaharsoughi Z, Patel TP, Brady SM, Chivukula KK, Miller E, Han JM, Periwal V, Wolska A, Remaley AT, Dagur PK, Biancotto A, Babyak A, Fantoni G, Yanovski JA, Demidowich AP. Effects of colchicine on lipolysis and adipose tissue inflammation in adults with obesity and metabolic syndrome. Obesity (Silver Spring) 2022; 30:358-368. [PMID: 34978374 PMCID: PMC8799499 DOI: 10.1002/oby.23341] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The aim of this study was to examine whether colchicine's anti-inflammatory effects would improve measures of lipolysis and distribution of leukocyte populations in subcutaneous adipose tissue (SAT). METHODS A secondary analysis was conducted for a double-blind, randomized, placebo-controlled pilot study in which 40 adults with obesity and metabolic syndrome (MetS) were randomized to colchicine 0.6 mg or placebo twice daily for 3 months. Non-insulin-suppressible (l0 ), insulin-suppressible (l2 ), and maximal (l0 +l2 ) lipolysis rates were calculated by minimal model analysis. Body composition was determined by dual-energy x-ray absorptiometry. SAT leukocyte populations were characterized by flow cytometry analysis from biopsied samples obtained before and after the intervention. RESULTS Colchicine treatment significantly decreased l2 and l0 +l2 versus placebo (p < 0.05). These changes were associated with a significant reduction in markers of systemic inflammation, including high-sensitivity C-reactive protein, resistin, and circulating monocytes and neutrophils (p < 0.01). Colchicine did not significantly alter SAT leukocyte population distributions (p > 0.05). CONCLUSIONS In adults with obesity and MetS, colchicine appears to improve insulin regulation of lipolysis and reduce markers of systemic inflammation independent of an effect on local leukocyte distributions in SAT. Further studies are needed to better understand the mechanisms by which colchicine affects adipose tissue metabolic pathways in adults with obesity and MetS.
Collapse
Affiliation(s)
- Jordan A Levine
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Zahra Sarrafan-Chaharsoughi
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Tushar P Patel
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Sheila M Brady
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - K Karthik Chivukula
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- Clinical Endocrinology Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Emily Miller
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Jung Min Han
- Computational Medicine Section, Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Vipul Periwal
- Computational Medicine Section, Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Anna Wolska
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Alan T Remaley
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Pradeep K Dagur
- Flow Cytometry Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Angelique Biancotto
- Center for Human Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Ashley Babyak
- Center for Human Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Giovanna Fantoni
- Center for Human Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Jack A Yanovski
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew P Demidowich
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- Johns Hopkins Community Physicians at Howard County General Hospital, Johns Hopkins Medicine, Columbia, Maryland, USA
- Department of Endocrinology, Diabetes and Metabolism, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
11
|
Kulminskaya N, Radler C, Viertlmayr R, Heier C, Hofer P, Colaço-Gaspar M, Owens RJ, Zimmermann R, Schreiber R, Zechner R, Oberer M. Optimized expression and purification of adipose triglyceride lipase improved hydrolytic and transacylation activities in vitro. J Biol Chem 2021; 297:101206. [PMID: 34543623 PMCID: PMC8506970 DOI: 10.1016/j.jbc.2021.101206] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 09/06/2021] [Accepted: 09/15/2021] [Indexed: 11/21/2022] Open
Abstract
Adipose triglyceride lipase (ATGL) plays a key role in intracellular lipolysis, the mobilization of stored triacylglycerol. This work provides an important basis for generating reproducible and detailed data on the hydrolytic and transacylation activities of ATGL. We generated full-length and C-terminally truncated ATGL variants fused with various affinity tags and analyzed their expression in different hosts, namely E.coli, the insect cell line Sf9, and the mammalian cell line human embryonic kidney 293T. Based on this screen, we expressed a fusion protein of ATGL covering residues M1-D288 flanked with N-terminal and C-terminal purification tags. Using these fusions, we identified key steps in expression and purification protocols, including production in the E. coli strain ArcticExpress (DE3) and removal of copurified chaperones. The resulting purified ATGL variant demonstrated improved lipolytic activity compared with previously published data, and it could be stimulated by the coactivator protein comparative gene identification-58 and inhibited by the protein G0/G1 switch protein 2. Shock freezing and storage did not affect the basal activity but reduced coactivation of ATGL by comparative gene identification 58. In vitro, the truncated ATGL variant demonstrated acyl-CoA-independent transacylation activity when diacylglycerol was offered as substrate, resulting in the formation of fatty acid as well as triacylglycerol and monoacylglycerol. However, the ATGL variant showed neither hydrolytic activity nor transacylation activity upon offering of monoacylglycerol as substrate. To understand the role of ATGL in different physiological contexts, it is critical for future studies to identify all its different functions and to determine under what conditions these activities occur.
Collapse
Affiliation(s)
| | - Claudia Radler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Roland Viertlmayr
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Raymond J Owens
- Division of Structural Biology, The Welcome Centre for Human Genetics, University of Oxford, Oxford, UK; Protein Production UK, Research Complex at Harwell, Didcot, UK
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria
| | - Monika Oberer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria.
| |
Collapse
|
12
|
SR-BI deficiency disassociates obesity from hepatic steatosis and glucose intolerance development in high fat diet-fed mice. J Nutr Biochem 2021; 89:108564. [DOI: 10.1016/j.jnutbio.2020.108564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023]
|
13
|
Uncovering the Role of Glycogen in Brown Adipose Tissue. Pharm Res 2021; 38:9-14. [PMID: 33433776 DOI: 10.1007/s11095-020-02979-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Abstract
The presence of glycogen in the brown adipose tissue (BAT) has been described 60 years ago. However, the role of this energetic storage in brown adipocytes has been long time underestimated. We have recently shown that during brown adipocyte differentiation in the embryo, glycogen accumulates and is degraded by glycophagy, a dynamic essential for lipid droplets biogenesis. Recent studies have shown that the storage and degradation of triglycerides in BAT are not essential for the activation of BAT in response to cold exposure in adults, and that glycogen can compensate for their absence. In this review, we report the recent advances related to the importance of glycogen in brown adipocytes.
Collapse
|
14
|
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.
Collapse
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.
| |
Collapse
|
15
|
The Influence of Physical Activity on the Bioactive Lipids Metabolism in Obesity-Induced Muscle Insulin Resistance. Biomolecules 2020; 10:biom10121665. [PMID: 33322719 PMCID: PMC7764345 DOI: 10.3390/biom10121665] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 12/14/2022] Open
Abstract
High-fat diet consumption and lack of physical activity are important risk factors for metabolic disorders such as insulin resistance and cardiovascular diseases. Insulin resistance is a state of a weakened response of tissues such as skeletal muscle, adipose tissue, and liver to insulin, which causes an increase in blood glucose levels. This condition is the result of inhibition of the intracellular insulin signaling pathway. Skeletal muscle is an important insulin-sensitive tissue that accounts for about 80% of insulin-dependent glucose uptake. Although the exact mechanism by which insulin resistance is induced has not been thoroughly understood, it is known that insulin resistance is most commonly associated with obesity. Therefore, it is believed that lipids may play an important role in inducing insulin resistance. Among lipids, researchers’ attention is mainly focused on biologically active lipids: diacylglycerols (DAG) and ceramides. These lipids are able to regulate the activity of intracellular enzymes, including those involved in insulin signaling. Available data indicate that physical activity affects lipid metabolism and has a positive effect on insulin sensitivity in skeletal muscles. In this review, we have presented the current state of knowledge about the impact of physical activity on insulin resistance and metabolism of biologically active lipids.
Collapse
|
16
|
Biochemical adaptations in white adipose tissue following aerobic exercise: from mitochondrial biogenesis to browning. Biochem J 2020; 477:1061-1081. [PMID: 32187350 DOI: 10.1042/bcj20190466] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/24/2020] [Accepted: 02/28/2020] [Indexed: 02/07/2023]
Abstract
Our understanding of white adipose tissue (WAT) biochemistry has evolved over the last few decades and it is now clear that WAT is not simply a site of energy storage, but rather a pliable endocrine organ demonstrating dynamic responsiveness to the effects of aerobic exercise. Similar to its established effects in skeletal muscle, aerobic exercise induces many biochemical adaptations in WAT including mitochondrial biogenesis and browning. While past research has focused on the regulation of these biochemical processes, there has been renewed interest as of late given the potential of harnessing WAT mitochondrial biogenesis and browning to treat obesity and type II diabetes. Unfortunately, despite increasing evidence that innumerable factors, both exercise induced and pharmacological, can elicit these biochemical adaptations in WAT, the underlying mechanisms remain poorly defined. Here, we begin with a historical account of our understanding of WAT exercise biochemistry before presenting detailed evidence in favour of an up-to-date model by which aerobic exercise induces mitochondrial biogenesis and browning in WAT. Specifically, we discuss how aerobic exercise induces increases in WAT lipolysis and re-esterification and how this could be a trigger that activates the cellular energy sensor 5' AMP-activated protein kinase to mediate the induction of mitochondrial biogenesis and browning via the transcriptional co-activator peroxisome proliferator-activated receptor gamma co-activator-1 alpha. While this review primarily focuses on mechanistic results from rodent studies special attention is given to the translation of these results, or lack thereof, to human physiology.
Collapse
|
17
|
Adipocyte lipolysis: from molecular mechanisms of regulation to disease and therapeutics. Biochem J 2020; 477:985-1008. [PMID: 32168372 DOI: 10.1042/bcj20190468] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/19/2020] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
Abstract
Fatty acids (FAs) are stored safely in the form of triacylglycerol (TAG) in lipid droplet (LD) organelles by professional storage cells called adipocytes. These lipids are mobilized during adipocyte lipolysis, the fundamental process of hydrolyzing TAG to FAs for internal or systemic energy use. Our understanding of adipocyte lipolysis has greatly increased over the past 50 years from a basic enzymatic process to a dynamic regulatory one, involving the assembly and disassembly of protein complexes on the surface of LDs. These dynamic interactions are regulated by hormonal signals such as catecholamines and insulin which have opposing effects on lipolysis. Upon stimulation, patatin-like phospholipase domain containing 2 (PNPLA2)/adipocyte triglyceride lipase (ATGL), the rate limiting enzyme for TAG hydrolysis, is activated by the interaction with its co-activator, alpha/beta hydrolase domain-containing protein 5 (ABHD5), which is normally bound to perilipin 1 (PLIN1). Recently identified negative regulators of lipolysis include G0/G1 switch gene 2 (G0S2) and PNPLA3 which interact with PNPLA2 and ABHD5, respectively. This review focuses on the dynamic protein-protein interactions involved in lipolysis and discusses some of the emerging concepts in the control of lipolysis that include allosteric regulation and protein turnover. Furthermore, recent research demonstrates that many of the proteins involved in adipocyte lipolysis are multifunctional enzymes and that lipolysis can mediate homeostatic metabolic signals at both the cellular and whole-body level to promote inter-organ communication. Finally, adipocyte lipolysis is involved in various diseases such as cancer, type 2 diabetes and fatty liver disease, and targeting adipocyte lipolysis is of therapeutic interest.
Collapse
|
18
|
Associations of GlycA and high-sensitivity C-reactive protein with measures of lipolysis in adults with obesity. J Clin Lipidol 2020; 14:667-674. [PMID: 32863171 DOI: 10.1016/j.jacl.2020.07.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/21/2020] [Accepted: 07/28/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Obesity-associated inflammation promotes metabolic dysfunction. However, it is unclear how different inflammatory biomarkers predict dysregulation in specific tissues/organs, particularly adipose tissue. OBJECTIVE The aim of our study was to examine whether GlycA, a nuclear magnetic resonance-measured biomarker of inflammation, is a better predictor of insulin-suppressible lipolysis and other measures of metabolic dysfunction compared with high-sensitivity C-reactive protein (hsCRP) in human obesity. METHODS This was a cross-sectional study of 58 nondiabetic adults with obesity (body mass index: 39.8 ± 7.0 kg/m2, age 46.5 ± 12.2 years, 67.2% female) who underwent a frequently sampled intravenous glucose tolerance test in the fasted state. Noninsulin-suppressible (l0), insulin-suppressible (l2), and maximal (l0+l2) lipolysis rates, as well as insulin sensitivity and acute insulin response to glucose, were calculated by minimal model analysis. Nuclear magnetic resonance was used to measure GlycA. Body composition was determined by dual-energy X-ray absorptiometry. RESULTS GlycA was strongly correlated with hsCRP (r = +0.46; P < .001). GlycA and hsCRP were positively associated with l2, l0+l2, and fat mass (Ps < .01). In linear regression models accounting for age, race, sex, and fat mass, GlycA remained significantly associated with l2 and l0+l2 (Ps < .05), whereas hsCRP did not (Ps ≥ .20). Neither GlycA nor hsCRP was associated with l0, insulin sensitivity, or acute insulin response to glucose. CONCLUSIONS GlycA was associated with elevated lipolysis, independent of adiposity, in adults with obesity. Our findings suggest that GlycA and hsCRP have distinct inflammation-mediated metabolic effects, with GlycA having a greater association with adipose tissue dysfunction. Further studies are warranted to investigate the mechanisms underlying these associations.
Collapse
|
19
|
Reinisch I, Schreiber R, Prokesch A. Regulation of thermogenic adipocytes during fasting and cold. Mol Cell Endocrinol 2020; 512:110869. [PMID: 32439414 DOI: 10.1016/j.mce.2020.110869] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022]
Abstract
Cold exposure activates brown and brown-like adipocytes that dissipate large amounts of glucose and fatty acids via uncoupling protein 1 (UCP1) to drive non-shivering thermogenesis (NST). Evidence for the existence of these thermogenic adipocytes in adult humans gave rise to a renaissance in research on brown adipose tissue, establishing it as linchpin of energy homeostasis and metabolic health. Besides low ambient temperature, shortage or excess of food affect thermoregulation. Upon high caloric meals thermogenic adipocytes burn excess calories and maintain energy balance. In contrast, in conditions of nutrient deprivation, counter-regulatory mechanisms prevent thermogenic adipocytes from "wasting" energy substrates that need to be conserved. In this review, we discuss cell-autonomous mechanisms, metabolites, and hormones that modify NST in response to nutrient fluctuations. In particular, we focus on how thermogenic adipocytes balance thermogenesis with systemic energy homeostasis during fasting periods.
Collapse
Affiliation(s)
- Isabel Reinisch
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism & Aging, Medical University of Graz, 8010, Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, 8010, Graz, Austria
| | - Andreas Prokesch
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism & Aging, Medical University of Graz, 8010, Graz, Austria; BioTechMed-Graz, 8010, Graz, Austria.
| |
Collapse
|
20
|
Coleman RA. The "discovery" of lipid droplets: A brief history of organelles hidden in plain sight. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158762. [PMID: 32622088 DOI: 10.1016/j.bbalip.2020.158762] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 06/24/2020] [Accepted: 06/29/2020] [Indexed: 12/14/2022]
Abstract
Mammalian lipid droplets (LDs), first described as early as the 1880s, were virtually ignored for more than 100 years. Between 1991 and the early 2000s, however, a series of discoveries and conceptual breakthroughs led to a resurgent interest in obesity as a disease, in the metabolism of intracellular triacylglycerol (TAG), and in the physical locations of LDs as cellular structures with their associated proteins. Insights included the recognition that obesity underlies major chronic diseases, that appetite is hormonally controlled, that hepatic steatosis is not a benign finding, and that diabetes might fundamentally be a disorder of lipid metabolism. In this brief review, I describe the metamorphosis of LDs from overlooked globs of stored fat to dynamic organelles that control insulin resistance, mitochondrial oxidation, and viral replication.
Collapse
Affiliation(s)
- Rosalind A Coleman
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America.
| |
Collapse
|
21
|
Kahn CR, Wang G, Lee KY. Altered adipose tissue and adipocyte function in the pathogenesis of metabolic syndrome. J Clin Invest 2020; 129:3990-4000. [PMID: 31573548 DOI: 10.1172/jci129187] [Citation(s) in RCA: 361] [Impact Index Per Article: 90.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Over the past decade, great progress has been made in understanding the complexity of adipose tissue biology and its role in metabolism. This includes new insights into the multiple layers of adipose tissue heterogeneity, not only differences between white and brown adipocytes, but also differences in white adipose tissue at the depot level and even heterogeneity of white adipocytes within a single depot. These inter- and intra-depot differences in adipocytes are developmentally programmed and contribute to the wide range of effects observed in disorders with fat excess (overweight/obesity) or fat loss (lipodystrophy). Recent studies also highlight the underappreciated dynamic nature of adipose tissue, including potential to undergo rapid turnover and dedifferentiation and as a source of stem cells. Finally, we explore the rapidly expanding field of adipose tissue as an endocrine organ, and how adipose tissue communicates with other tissues to regulate systemic metabolism both centrally and peripherally through secretion of adipocyte-derived peptide hormones, inflammatory mediators, signaling lipids, and miRNAs packaged in exosomes. Together these attributes and complexities create a robust, multidimensional signaling network that is central to metabolic homeostasis.
Collapse
Affiliation(s)
- C Ronald Kahn
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Guoxiao Wang
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Kevin Y Lee
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and.,The Diabetes Institute, Ohio University, Athens, Ohio, USA
| |
Collapse
|
22
|
Zhao J, Wu Y, Rong X, Zheng C, Guo J. Anti-Lipolysis Induced by Insulin in Diverse Pathophysiologic Conditions of Adipose Tissue. Diabetes Metab Syndr Obes 2020; 13:1575-1585. [PMID: 32494174 PMCID: PMC7227813 DOI: 10.2147/dmso.s250699] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 04/19/2020] [Indexed: 12/13/2022] Open
Abstract
As an important energy reservoir, adipose tissue maintains lipid balance and regulates energy metabolism. When the body requires energy, adipocytes provide fatty acids to peripheral tissues through lipolysis. Insulin plays an important role in regulating normal fatty acid levels by inhibiting lipolysis. When the morphology of adipose tissue is abnormal, its microenvironment changes and the lipid metabolic balance is disrupted, which seriously impairs insulin sensitivity. As the most sensitive organ to respond to insulin, lipolysis levels in adipose tissue are affected by impaired insulin function, which results in serious metabolic diseases. However, the specific underlying mechanisms of this process have not yet been fully elucidated, and further study is required. The purpose of this review is to discuss the effects of adipose tissue on the anti-lipolysis process triggered by insulin under different conditions. In particular, the functional changes of this process respond to inconsonantly morphological changes of adipose tissue.
Collapse
Affiliation(s)
- Jia Zhao
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
| | - YaYun Wu
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
| | - XiangLu Rong
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
- Guangdong TCM Key Laboratory for the Prevention and Treatment of Metabolic Diseases, Guangdong, People's Republic of China
- Joint Laboratory of Guangdong Province and Hong Kong and Macao Regions on Metabolic Diseases, Guangdong, People's Republic of China
| | - CuiWen Zheng
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
| | - Jiao Guo
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
- Guangdong TCM Key Laboratory for the Prevention and Treatment of Metabolic Diseases, Guangdong, People's Republic of China
- Joint Laboratory of Guangdong Province and Hong Kong and Macao Regions on Metabolic Diseases, Guangdong, People's Republic of China
| |
Collapse
|
23
|
Yu L, Li Y, Grisé A, Wang H. CGI-58: Versatile Regulator of Intracellular Lipid Droplet Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:197-222. [PMID: 32705602 PMCID: PMC8063591 DOI: 10.1007/978-981-15-6082-8_13] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Comparative gene identification-58 (CGI-58), also known as α/β-hydrolase domain-containing 5 (ABHD5), is a member of a large family of proteins containing an α/β-hydrolase-fold. CGI-58 is well-known as the co-activator of adipose triglyceride lipase (ATGL), which is a key enzyme initiating cytosolic lipid droplet lipolysis. Mutations in either the human CGI-58 or ATGL gene cause an autosomal recessive neutral lipid storage disease, characterized by the excessive accumulation of triglyceride (TAG)-rich lipid droplets in the cytoplasm of almost all cell types. CGI-58, however, has ATGL-independent functions. Distinct phenotypes associated with CGI-58 deficiency commonly include ichthyosis (scaly dry skin), nonalcoholic steatohepatitis, and hepatic fibrosis. Through regulated interactions with multiple protein families, CGI-58 controls many metabolic and signaling pathways, such as lipid and glucose metabolism, energy balance, insulin signaling, inflammatory responses, and thermogenesis. Recent studies have shown that CGI-58 regulates the pathogenesis of common metabolic diseases in a tissue-specific manner. Future studies are needed to molecularly define ATGL-independent functions of CGI-58, including the newly identified serine protease activity of CGI-58. Elucidation of these versatile functions of CGI-58 may uncover fundamental cellular processes governing lipid and energy homeostasis, which may help develop novel approaches that counter against obesity and its associated metabolic sequelae.
Collapse
Affiliation(s)
- Liqing Yu
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Yi Li
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alison Grisé
- College of Computer, Math, and Natural Sciences, College of Behavioral and Social Sciences, University of Maryland, College Park, MD, USA
| | - Huan Wang
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
24
|
Zhang X, Zhang CC, Yang H, Soni KG, Wang SP, Mitchell GA, Wu JW. An Epistatic Interaction between Pnpla2 and Lipe Reveals New Pathways of Adipose Tissue Lipolysis. Cells 2019; 8:cells8050395. [PMID: 31035700 PMCID: PMC6563012 DOI: 10.3390/cells8050395] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/17/2019] [Accepted: 04/23/2019] [Indexed: 12/20/2022] Open
Abstract
White adipose tissue (WAT) lipolysis contributes to energy balance during fasting. Lipolysis can proceed by the sequential hydrolysis of triglycerides (TGs) by adipose triglyceride lipase (ATGL), then of diacylglycerols (DGs) by hormone-sensitive lipase (HSL). We showed that the combined genetic deficiency of ATGL and HSL in mouse adipose tissue produces a striking different phenotype from that of isolated ATGL deficiency, inconsistent with the linear model of lipolysis. We hypothesized that the mechanism might be functional redundancy between ATGL and HSL. To test this, the TG hydrolase activity of HSL was measured in WAT. HSL showed TG hydrolase activity. Then, to test ATGL for activity towards DGs, radiolabeled DGs were incubated with HSL-deficient lipid droplet fractions. The content of TG increased, suggesting DG-to-TG synthesis rather than DG hydrolysis. TG synthesis was abolished by a specific ATGL inhibitor, suggesting that ATGL functions as a transacylase when HSL is deficient, transferring an acyl group from one DG to another, forming a TG plus a monoglyceride (MG) that could be hydrolyzed by monoglyceride lipase. These results reveal a previously unknown physiological redundancy between ATGL and HSL, a mechanism for the epistatic interaction between Pnpla2 and Lipe. It provides an alternative lipolytic pathway, potentially important in patients with deficient lipolysis.
Collapse
Affiliation(s)
- Xiao Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Cong Cong Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Hao Yang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Krishnakant G Soni
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030, USA.
| | - Shu Pei Wang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Grant A Mitchell
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| |
Collapse
|
25
|
Liu X, Wei S, Deng S, Li D, Liu K, Shan B, Shao Y, Wei W, Chen J, Zhang L. Genome-wide identification and comparison of mRNAs, lncRNAs and circRNAs in porcine intramuscular, subcutaneous, retroperitoneal and mesenteric adipose tissues. Anim Genet 2019; 50:228-241. [PMID: 30982992 DOI: 10.1111/age.12781] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2019] [Indexed: 01/31/2023]
Abstract
Many types of RNAs, including messenger RNAs (mRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play crucial roles in regulating fat cell differentiation and tissue development. However, the expression profiles of these RNAs in different adipose tissues are still largely unknown. To shed light on this issue, we performed a transcriptome analysis of mRNAs, lncRNAs and circRNAs obtained from intramuscular adipose tissue, subcutaneous adipose tissue, retroperitoneal adipose tissue and mesenteric adipose tissue of Chinese Erhualian pigs. A number of differentially expressed mRNAs, lncRNAs and circRNAs were identified among the four adipose tissues. Tissue-specific analysis indicated that circRNAs exhibited the highest tissue specificity among mRNAs, lncRNAs and circRNAs, whereas intramuscular adipose tissue had the most tissue-specific genes among the four adipose tissues. Gene Ontology analysis showed that differentially expressed mRNAs among groups were involved mainly in lipid metabolism and immune inflammatory response processes. Furthermore, the co-expression network construction of mRNAs-lncRNAs revealed that several important lncRNAs, such as MSTRG.426159 and MSTRG.604206, might associate with lipid metabolic process. Taken together, these data provide a genome-wide resource of mRNAs, lncRNAs and circRNAs potentially involved in porcine fat metabolism, thus improving understanding of their function in diverse adipose tissues.
Collapse
Affiliation(s)
- X Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - S Wei
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - S Deng
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - D Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - K Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - B Shan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Y Shao
- College of Animal Science, Xinjiang Agricultural University, Urumqi, 830052, China
| | - W Wei
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - J Chen
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - L Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| |
Collapse
|
26
|
Of mice and men: The physiological role of adipose triglyceride lipase (ATGL). Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:880-899. [PMID: 30367950 PMCID: PMC6439276 DOI: 10.1016/j.bbalip.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) has been discovered 14 years ago and revised our view on intracellular triglyceride (TG) mobilization – a process termed lipolysis. ATGL initiates the hydrolysis of TGs to release fatty acids (FAs) that are crucial energy substrates, precursors for the synthesis of membrane lipids, and ligands of nuclear receptors. Thus, ATGL is a key enzyme in whole-body energy homeostasis. In this review, we give an update on how ATGL is regulated on the transcriptional and post-transcriptional level and how this affects the enzymes' activity in the context of neutral lipid catabolism. In depth, we highlight and discuss the numerous physiological functions of ATGL in lipid and energy metabolism. Over more than a decade, different genetic mouse models lacking or overexpressing ATGL in a cell- or tissue-specific manner have been generated and characterized. Moreover, pharmacological studies became available due to the development of a specific murine ATGL inhibitor (Atglistatin®). The identification of patients with mutations in the human gene encoding ATGL and their disease spectrum has underpinned the importance of ATGL in humans. Together, mouse models and human data have advanced our understanding of the physiological role of ATGL in lipid and energy metabolism in adipose and non-adipose tissues, and of the pathophysiological consequences of ATGL dysfunction in mice and men. Summary of mouse models with genetic or pharmacological manipulation of ATGL. Summary of patients with mutations in the human gene encoding ATGL. In depth discussion of the role of ATGL in numerous physiological processes in mice and men.
Collapse
|
27
|
Xu M, Chang HH, Jung X, Moro A, Chou CEN, King J, Hines OJ, Sinnett-Smith J, Rozengurt E, Eibl G. Deficiency in hormone-sensitive lipase accelerates the development of pancreatic cancer in conditional KrasG12D mice. BMC Cancer 2018; 18:797. [PMID: 30086728 PMCID: PMC6081906 DOI: 10.1186/s12885-018-4713-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 07/31/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Hormone sensitive lipase (HSL) is a neutral lipase that preferentially catalyzes the hydrolysis of diacylglycerol contributing to triacylglycerol breakdown in the adipose tissue. HSL has been implicated to play a role in tumor cachexia, a debilitating syndrome characterized by progressive loss of adipose tissue. Consequently, pharmacological inhibitors of HSL have been proposed for the treatment of cancer-associated cachexia. In the present study we used the conditional KrasG12D (KC) mouse model of pancreatic ductal adenocarcinoma (PDAC) with a deficiency in HSL to determine the impact of HSL suppression on the development of PDAC. METHODS KC;Hsl+/+ and KC;Hsl-/- mice were fed standard rodent chow for 20 weeks. At sacrifice, the incidence of PDAC was determined and inflammation in the mesenteric adipose tissue and pancreas was assessed histologically and by immunofluorescence. To determine statistical significance, ANOVA and two-tailed Student's t-tests were performed. To compare PDAC incidence, a two-sided Fisher's exact test was used. RESULTS Compared to KC;Hsl+/+ mice, KC;Hsl-/- mice gained similar weight and displayed adipose tissue and pancreatic inflammation. In addition, KC;Hsl-/- mice had reduced levels of plasma insulin and leptin. Importantly, the increased adipose tissue and pancreatic inflammation was associated with a significant increase in PDAC incidence in KC;Hsl-/- mice. CONCLUSIONS HSL deficiency is associated with adipose tissue and pancreatic inflammation and accelerates PDAC development in the KC mouse model.
Collapse
Affiliation(s)
- Mu Xu
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
| | - Hui-Hua Chang
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
- CURE: Digestive Diseases Research Center, University of California at Los Angeles, Los Angeles, USA
| | - Xiaoman Jung
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
| | - Aune Moro
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
| | - Caroline Ei Ne Chou
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
| | - Jonathan King
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
| | - O. Joe Hines
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
| | - James Sinnett-Smith
- Departments of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA USA
- CURE: Digestive Diseases Research Center, University of California at Los Angeles, Los Angeles, USA
| | - Enrique Rozengurt
- Departments of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA USA
- CURE: Digestive Diseases Research Center, University of California at Los Angeles, Los Angeles, USA
| | - Guido Eibl
- Departments of Surgery, David Geffen School of Medicine, University of California, Los Angeles, 10833 Le Conte Ave, CHS 72-236, Los Angeles, CA 90095 USA
- CURE: Digestive Diseases Research Center, University of California at Los Angeles, Los Angeles, USA
| |
Collapse
|
28
|
Ding Y, Cui J, Wang Q, Shen S, Xu T, Tang H, Han M, Wu X. The Vitamin K Epoxide Reductase Vkorc1l1 Promotes Preadipocyte Differentiation in Mice. Obesity (Silver Spring) 2018; 26:1303-1311. [PMID: 29963761 DOI: 10.1002/oby.22206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 04/12/2018] [Accepted: 04/16/2018] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Identification of novel regulators involved in adipose development is important to understand the molecular mechanism underlying obesity and associated metabolic disorders. Through isolation and analysis of a vitamin K epoxide reductase Vkorc1l1 mutant, this study aimed to disclose its function and underlying mechanism in adipose development and to obtain valuable insights regarding the mechanism of obesity. METHODS A Vkorc1l1 mutation recovered from a forward genetic screen for obesity-related loci in mice was characterized to explore its effects in gene expression, animal metabolism, and adipose development. Adipogenesis was evaluated in both Vkorc1l1 mutant stromal vascular fraction and Vkorc1l1 knockdown preadipocytes. Intracellular vitamin K2 level and the effect of vitamin K2 on adipogenesis were tested in primary preadipocytes. RESULTS Vkorc1l1 mutants displayed a considerably lower fat to body weight ratio, substantially decreased plasma leptin, and significantly underdeveloped white adipose tissue. Adipogenic defects related with Vkorc1l1 deficiency were observed both in vivo and in vitro. Vitamin K2 could inhibit adipogenesis in stromal vascular fraction. Increased intracellular vitamin K2 level was detected in Vkorc1l1 mutant preadipocytes. CONCLUSIONS Vkorc1l1 promotes adipogenesis and possibly obesity. Downregulation of Vkorc1l1 increases intracellular vitamin K2 level and impedes preadipocyte differentiation.
Collapse
Affiliation(s)
- Yi Ding
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Institute of Developmental Biology and Molecular Medicine, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Jing Cui
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Institute of Developmental Biology and Molecular Medicine, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Qi Wang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, University of Chinese Academy of Sciences, Wuhan, China
| | - Suqin Shen
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Tian Xu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Institute of Developmental Biology and Molecular Medicine, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
- Department of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Huiru Tang
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Institute of Developmental Biology and Molecular Medicine, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Min Han
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Institute of Developmental Biology and Molecular Medicine, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
- Department of Molecular, Cellular, and Developmental Biology, Howard Hughes Medical Institute, University of Colorado, Boulder, Colorado, USA
| | - Xiaohui Wu
- State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Institute of Developmental Biology and Molecular Medicine, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| |
Collapse
|
29
|
Dai YJ, Liu WB, Li XF, Zhou M, Xu C, Qian Y, Jiang GZ. Molecular cloning of adipose triglyceride lipase (ATGL) gene from blunt snout bream and its expression after LPS-induced TNF-α factor. FISH PHYSIOLOGY AND BIOCHEMISTRY 2018; 44:1143-1157. [PMID: 29705966 DOI: 10.1007/s10695-018-0502-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
The aims of the present study were to clone the full-length cDNA of adipose triglyceridelipase (ATGL) and to analyze its expression after lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-α). The cDNA obtained covered 1801 bp with an open reading frame of 1500 bp encoding 499 amino acids. Sequence alignment and phylogenetic analysis show the best identity with Cyprinus carpio (86%). The ATGL protein shared a highly conserved 169-amino acid patatin domain, containing a glycine-rich motif, an active serine hydrolase motif, and an aspartic active site. The highest ATGL expression was observed in the liver followed by muscle, whereas relatively low values were detected in the brain and adipose. TNF-α is regarded as an important factor in regulating fat metabolism. Here, LPS was used to induce TNF-α in vivo to verify whether TNF-α can affect ATGL expression. TNF-α expression in liver and muscle is increased and remains unchanged in adipose tissue and brain. The variation of ATGL activity is consistent with that of TNF-α gene expression. Next, we explored the mechanism by which LPS-induced TNF-α mediates the mRNA expression of ATGL in the liver and muscle. For liver, the mRNA levels of c-Jun N-terminal kinase (JNK), nuclear factor kappa B (NF-κB), Sirtuin 1 (SIRT1), and AMP-activated protein kinase (AMPK) were increased by LPS-induced TNF-α. Differencing from the situation in the liver, there was a near-significant decrease trend in the expression of SIRT1 in muscle. Those results indicated that the ATGL gene of blunt snout bream shared a high similarity with the other vertebrates. The expression level of ATGL in tissues with high-fat content was intended to be high. LPS can induce ATGL expression perhaps related to TNF-α.
Collapse
Affiliation(s)
- Yong-Jun Dai
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No.1 Weigang Road, Nanjing, 210095, People's Republic of China
| | - Wen-Bin Liu
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No.1 Weigang Road, Nanjing, 210095, People's Republic of China
| | - Xiang-Fei Li
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No.1 Weigang Road, Nanjing, 210095, People's Republic of China
| | - Man Zhou
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No.1 Weigang Road, Nanjing, 210095, People's Republic of China
| | - Chao Xu
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No.1 Weigang Road, Nanjing, 210095, People's Republic of China
| | - Yu Qian
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No.1 Weigang Road, Nanjing, 210095, People's Republic of China
| | - Guang-Zhen Jiang
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, No.1 Weigang Road, Nanjing, 210095, People's Republic of China.
| |
Collapse
|
30
|
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]
|
31
|
Hu JN, Shen JR, Xiong CY, Zhu XM, Deng ZY. Investigation of Lipid Metabolism by a New Structured Lipid with Medium- and Long-Chain Triacylglycerols from Cinnamomum camphora Seed Oil in Healthy C57BL/6J Mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:1990-1998. [PMID: 29429331 DOI: 10.1021/acs.jafc.7b05659] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In the present study, a new structured lipid with medium- and long-chain triacylglycerols (MLCTs) was synthesized from camellia oil (CO) and Cinnamomum camphora seed oil (CCSO) by enzymatic interesterification. Meanwhile, the antiobesity effects of structured lipid were investigated through observing the changes of enzymes related to lipid mobilization in healthy C57BL/6J mice. Results showed that after synthesis, the major triacylgeride (TAG) species of intesterificated product changed to LaCC/CLaC (12.6 ± 0.46%), LaCO/LCL (21.7 ± 0.76%), CCO/LaCL (14.2 ± 0.55%), COO/OCO (10.8 ± 0.43%), and OOO (18.6 ± 0.64%). Through second-stage molecular distillation, the purity of interesterified product (MLCT) achieved 95.6%. Later, male C57BL/6J mice were applied to study whether the new structured lipid with MLCT has the efficacy of preventing the formation of obesity or not. After feeding with different diets for 6 weeks, MLCTs could reduce body weight and fat deposition in adipose tissue, lower plasma triacylglycerols (TG) (0.89 ± 0.16 mmol/L), plasma total cholesterol (TC) (4.03 ± 0.08 mmol/L), and hepatic lipids (382 ± 34.2 mg/mice) by 28.8%, 16.0%, and 30.5%, respectively, when compared to the control 2 group. This was also accompanied by increasing fecal lipids (113%) and the level of enzymes including cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), hormone-sensitive lipase (HSL), and adipose triglyceride lipase (ATGL) related to lipid mobilization in MLCT group. From the results, it can be concluded that MLCT reduced body fat deposition probably by modulating enzymes related to lipid mobilization in C57BL/6J mice.
Collapse
Affiliation(s)
- Jiang-Ning Hu
- School of Food Science and Technology, Dalian Polytechnic University , Dalian 116034, China
- State Key Laboratory of Food Science and Technology, Institute for Advanced Study, Nanchang University , Nanchang, Jiangxi 330047, China
| | - Jin-Rong Shen
- State Key Laboratory of Food Science and Technology, Institute for Advanced Study, Nanchang University , Nanchang, Jiangxi 330047, China
| | - Chao-Yue Xiong
- State Key Laboratory of Food Science and Technology, Institute for Advanced Study, Nanchang University , Nanchang, Jiangxi 330047, China
| | - Xue-Mei Zhu
- School of Food Science and Technology, Dalian Polytechnic University , Dalian 116034, China
- State Key Laboratory of Food Science and Technology, Institute for Advanced Study, Nanchang University , Nanchang, Jiangxi 330047, China
| | - Ze-Yuan Deng
- State Key Laboratory of Food Science and Technology, Institute for Advanced Study, Nanchang University , Nanchang, Jiangxi 330047, China
| |
Collapse
|
32
|
Xia B, Cai GH, Yang H, Wang SP, Mitchell GA, Wu JW. Adipose tissue deficiency of hormone-sensitive lipase causes fatty liver in mice. PLoS Genet 2017; 13:e1007110. [PMID: 29232702 PMCID: PMC5741266 DOI: 10.1371/journal.pgen.1007110] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 12/22/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023] Open
Abstract
Fatty liver is a major health problem worldwide. People with hereditary deficiency of hormone-sensitive lipase (HSL) are reported to develop fatty liver. In this study, systemic and tissue-specific HSL-deficient mice were used as models to explore the underlying mechanism of this association. We found that systemic HSL deficient mice developed fatty liver in an age-dependent fashion between 3 and 8 months of age. To further explore the mechanism of fatty liver in HSL deficiency, liver-specific HSL knockout mice were created. Surprisingly, liver HSL deficiency did not influence liver fat content, suggesting that fatty liver in HSL deficiency is not liver autonomous. Given the importance of adipose tissue in systemic triglyceride metabolism, we created adipose-specific HSL knockout mice and found that adipose HSL deficiency, to a similar extent as systemic HSL deficiency, causes age-dependent fatty liver in mice. Mechanistic study revealed that deficiency of HSL in adipose tissue caused inflammatory macrophage infiltrates, progressive lipodystrophy, abnormal adipokine secretion and systemic insulin resistance. These changes in adipose tissue were associated with a constellation of changes in liver: low levels of fatty acid oxidation, of very low density lipoprotein secretion and of triglyceride hydrolase activity, each favoring the development of hepatic steatosis. In conclusion, HSL-deficient mice revealed a complex interorgan interaction between adipose tissue and liver: the role of HSL in the liver is minimal but adipose tissue deficiency of HSL can cause age-dependent hepatic steatosis. Adipose tissue is a potential target for treating the hepatic steatosis of HSL deficiency. Fatty liver is a major complication of obesity and of type 2 diabetes mellitus. It carries a high risk of cirrhosis and liver cancer. In fatty liver, triglycerides accumulate to high levels in the cytoplasm of hepatocytes. Triglycerides are degraded by lipolysis, which has been most studied in fat cells where its three steps are catalyzed by different enzymes. The second step, hydrolysis of diglyceride to a monoglyceride, can be mediated by hormone-sensitive lipase (HSL). Patients with genetic deficiency of HSL have fatty liver. In this study, we found that systemic HSL deficient mice developed fatty liver with aging. To study the mechanism of steatosis, we made liver-specific HSL-deficient mice. Surprisingly, these mice had normal liver fat content. We then studied mice with HSL deficiency in adipose tissue. Adipose HSL-deficient mice developed hepatic steatosis to a similar extent as mice with systemic HSL deficiency, showing that adipose HSL deficiency is sufficient to cause fatty liver. Furthermore, like reported HSL-deficient humans, mice with adipose HSL deficiency had systemic insulin resistance, reduced fat mass and inflammation in fat tissue. Each of these is known to promote hepatic steatosis. Livers of adipose HSL-deficient mice showed low levels of hepatic fatty acid (FA) oxidation, of very low density lipoprotein (VLDL) secretion and of triglycerides (TG) hydrolase activity, each of which could contribute to fat accumulation in liver. Tissue-selective genetic alterations may help in identifying and understanding the tissues responsible for complex metabolic phenotypes like fatty liver. Our data suggest that at least in mice, strategies for treatment of fatty liver related to HSL deficiency should concentrate on adipose tissue.
Collapse
Affiliation(s)
- Bo Xia
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Guo He Cai
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Hao Yang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
| | - Shu Pei Wang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
| | - Grant A. Mitchell
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
- * E-mail: (JWW); (GAM)
| | - Jiang Wei Wu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, Montréal, QC, Canada
- * E-mail: (JWW); (GAM)
| |
Collapse
|
33
|
Schreiber R, Diwoky C, Schoiswohl G, Feiler U, Wongsiriroj N, Abdellatif M, Kolb D, Hoeks J, Kershaw EE, Sedej S, Schrauwen P, Haemmerle G, Zechner R. Cold-Induced Thermogenesis Depends on ATGL-Mediated Lipolysis in Cardiac Muscle, but Not Brown Adipose Tissue. Cell Metab 2017; 26:753-763.e7. [PMID: 28988821 PMCID: PMC5683855 DOI: 10.1016/j.cmet.2017.09.004] [Citation(s) in RCA: 216] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 07/07/2017] [Accepted: 09/05/2017] [Indexed: 11/29/2022]
Abstract
Fatty acids (FAs) activate and fuel UCP1-mediated non-shivering thermogenesis (NST) in brown adipose tissue (BAT). Release of FAs from intracellular fat stores by adipose triglyceride lipase (ATGL) is considered a key step in NST. Accordingly, the severe cold intolerance of global ATGL knockout (AKO) mice has been attributed to defective BAT lipolysis. Here we show that this conclusion is incorrect. We demonstrate that although the BAT-specific loss of ATGL impairs BAT lipolysis and alters BAT morphology, it does not compromise the β3-adrenergic thermogenic response or cold-induced NST. Instead, NST depends on nutrient supply or lipolysis in white adipose tissue during fasting, suggesting that circulating energy substrates are sufficient to fuel NST. Cold intolerance in AKO mice is not caused by BAT dysfunction as previously suspected but by severe cardiomyopathy. We conclude that functional NST requires adequate substrate supply and cardiac function, but does not depend on ATGL-mediated lipolysis in BAT.
Collapse
Affiliation(s)
- Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
| | - Clemens Diwoky
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | | | - Ursula Feiler
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | | | - Mahmoud Abdellatif
- Department of Cardiology, Medical University of Graz, 8036 Graz, Austria
| | - Dagmar Kolb
- Institute of Cell Biology, Histology, and Embryology, Core Facility of Ultrastructural Analyses, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria
| | - Joris Hoeks
- Department of Human Biology and Human Movement Sciences, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Erin E Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, 8036 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria
| | - Patrick Schrauwen
- Department of Human Biology and Human Movement Sciences, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
| |
Collapse
|
34
|
Berryman DE, List EO. Growth Hormone's Effect on Adipose Tissue: Quality versus Quantity. Int J Mol Sci 2017; 18:ijms18081621. [PMID: 28933734 PMCID: PMC5578013 DOI: 10.3390/ijms18081621] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/10/2017] [Accepted: 07/17/2017] [Indexed: 02/07/2023] Open
Abstract
Obesity is an excessive accumulation or expansion of adipose tissue (AT) due to an increase in either the size and/or number of its characteristic cell type, the adipocyte. As one of the most significant public health problems of our time, obesity and its associated metabolic complications have demanded that attention be given to finding effective therapeutic options aimed at reducing adiposity or the metabolic dysfunction associated with its accumulation. Growth hormone (GH) has therapeutic potential due to its potent lipolytic effect and resultant ability to reduce AT mass while preserving lean body mass. However, AT and its resident adipocytes are significantly more dynamic and elaborate than once thought and require one not to use the reduction in absolute mass as a readout of efficacy alone. Paradoxically, therapies that reduce GH action may ultimately prove to be healthier, in part because GH also possesses potent anti-insulin activities along with concerns that GH may promote the growth of certain cancers. This review will briefly summarize some of the newer complexities of AT relevant to GH action and describe the current understanding of how GH influences this tissue using data from both humans and mice. We will conclude by considering the therapeutic use of GH or GH antagonists in obesity, as well as important gaps in knowledge regarding GH and AT.
Collapse
Affiliation(s)
- Darlene E Berryman
- The Diabetes Institute at Ohio University, 108 Konneker Research Labs, Ohio University, Athens, OH 45701, USA.
- Edison Biotechnology Institute, 218 Konneker Research Labs, Ohio University, Athens, OH 45701, USA.
| | - Edward O List
- The Diabetes Institute at Ohio University, 108 Konneker Research Labs, Ohio University, Athens, OH 45701, USA.
- Edison Biotechnology Institute, 218 Konneker Research Labs, Ohio University, Athens, OH 45701, USA.
| |
Collapse
|
35
|
Takanashi M, Taira Y, Okazaki S, Takase S, Kimura T, Li CC, Xu PF, Noda A, Sakata I, Kumagai H, Ikeda Y, Iizuka Y, Yahagi N, Shimano H, Osuga JI, Ishibashi S, Kadowaki T, Okazaki H. Role of Hormone-sensitive Lipase in Leptin-Promoted Fat Loss and Glucose Lowering. J Atheroscler Thromb 2017; 24:1105-1116. [PMID: 28413180 PMCID: PMC5684476 DOI: 10.5551/jat.39552] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Aim: Myriad biological effects of leptin may lead to broad therapeutic applications for various metabolic diseases, including diabetes and its complications; however, in contrast to its anorexic effect, the molecular mechanisms underlying adipopenic and glucose-lowering effects of leptin have not been fully understood. Here we aim to clarify the role of hormone-sensitive lipase (HSL) in leptin's action. Methods: Wild-type (WT) and HSL-deficient (HSLKO) mice were made hyperleptinemic by two commonly-used methods: adenovirus-mediated overexpression of leptin and continuous subcutaneous infusion of leptin by osmotic pumps. The amount of food intake, body weights, organ weights, and parameters of glucose and lipid metabolism were measured. Results: Hyperleptinemia equally suppressed the food intake in WT and HSLKO mice. On the other hand, leptin-mediated fat loss and glucose-lowering were significantly blunted in the absence of HSL when leptin was overexpressed by recombinant adenovirus carrying leptin. By osmotic pumps, the fat-losing and glucose-lowering effects of leptin were milder due to lower levels of hyperleptinemia; although the difference between WT and HSLKO mice did not reach statistical significance, HSLKO mice had a tendency to retain more fat than WT mice in the face of hyperleptinemia. Conclusions: We clarify for the first time the role of HSL in leptin's effect using a genetic model: leptin-promoted fat loss and glucose-lowering are at least in part mediated via HSL-mediated lipolysis. Further studies to define the pathophysiological role of adipocyte lipases in leptin action may lead to a new therapeutic approach to circumvent leptin resistance.
Collapse
Affiliation(s)
- Mikio Takanashi
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Yoshino Taira
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Sachiko Okazaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Satoru Takase
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Takeshi Kimura
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Cheng Cheng Li
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Peng Fei Xu
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Akari Noda
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University
| | - Hidetoshi Kumagai
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Yuichi Ikeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Yoko Iizuka
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Naoya Yahagi
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Hitoshi Shimano
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Jun-Ichi Osuga
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University
| | - Takashi Kadowaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Hiroaki Okazaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| |
Collapse
|
36
|
Wang F, Chen Z, Ren X, Tian Y, Wang F, Liu C, Jin P, Li Z, Zhang F, Zhu B. Hormone-sensitive lipase deficiency alters gene expression and cholesterol content of mouse testis. Reproduction 2016; 153:175-185. [PMID: 27920259 PMCID: PMC5148802 DOI: 10.1530/rep-16-0484] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/04/2016] [Accepted: 11/10/2016] [Indexed: 12/15/2022]
Abstract
Hormone-sensitive lipase-knockout (HSL−/−) mice exhibit azoospermia for unclear reasons. To explore the basis of sterility, we performed the following three experiments. First, HSL protein distribution in the testis was determined. Next, transcriptome analyses were performed on the testes of three experimental groups. Finally, the fatty acid and cholesterol levels in the testes with three different genotypes studied were determined. We found that the HSL protein was present from spermatocyte cells to mature sperm acrosomes in wild-type (HSL+/+) testes. Spermiogenesis ceased at the elongation phase of HSL−/− testes. Transcriptome analysis indicated that genes involved in lipid metabolism, cell membrane, reproduction and inflammation-related processes were disordered in HSL−/− testes. The cholesterol content was significantly higher in HSL−/− than that in HSL+/+ testis. Therefore, gene expression and cholesterol ester content differed in HSL−/− testes compared to other testes, which may explain the sterility of male HSL−/− mice.
Collapse
Affiliation(s)
- Feng Wang
- College of Life SciencesCapital Normal University, Beijing, China
| | - Zheng Chen
- College of Life SciencesCapital Normal University, Beijing, China
| | - Xiaofang Ren
- College of Life SciencesCapital Normal University, Beijing, China
| | - Ye Tian
- College of Life SciencesCapital Normal University, Beijing, China
| | - Fucheng Wang
- College of Life SciencesCapital Normal University, Beijing, China
| | - Chao Liu
- College of Life SciencesCapital Normal University, Beijing, China
| | - Pengcheng Jin
- College of Life SciencesCapital Normal University, Beijing, China
| | - Zongyue Li
- College of Life SciencesCapital Normal University, Beijing, China
| | - Feixiong Zhang
- College of Life SciencesCapital Normal University, Beijing, China
| | - Baochang Zhu
- College of Life SciencesCapital Normal University, Beijing, China
| |
Collapse
|
37
|
Yan M, Audet-Walsh É, Manteghi S, Dufour CR, Walker B, Baba M, St-Pierre J, Giguère V, Pause A. Chronic AMPK activation via loss of FLCN induces functional beige adipose tissue through PGC-1α/ERRα. Genes Dev 2016; 30:1034-46. [PMID: 27151976 PMCID: PMC4863735 DOI: 10.1101/gad.281410.116] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 04/13/2016] [Indexed: 12/25/2022]
Abstract
The tumor suppressor folliculin (FLCN) forms a repressor complex with AMP-activated protein kinase (AMPK). Given that AMPK is a master regulator of cellular energy homeostasis, we generated an adipose-specific Flcn (Adipoq-FLCN) knockout mouse model to investigate the role of FLCN in energy metabolism. We show that loss of FLCN results in a complete metabolic reprogramming of adipose tissues, resulting in enhanced oxidative metabolism. Adipoq-FLCN knockout mice exhibit increased energy expenditure and are protected from high-fat diet (HFD)-induced obesity. Importantly, FLCN ablation leads to chronic hyperactivation of AMPK, which in turns induces and activates two key transcriptional regulators of cellular metabolism, proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) and estrogen-related receptor α (ERRα). Together, the AMPK/PGC-1α/ERRα molecular axis positively modulates the expression of metabolic genes to promote mitochondrial biogenesis and activity. In addition, mitochondrial uncoupling proteins as well as other markers of brown fat are up-regulated in both white and brown FLCN-null adipose tissues, underlying the increased resistance of Adipoq-FLCN knockout mice to cold exposure. These findings identify a key role of FLCN as a negative regulator of mitochondrial function and identify a novel molecular pathway involved in the browning of white adipocytes and the activity of brown fat.
Collapse
Affiliation(s)
- Ming Yan
- Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Étienne Audet-Walsh
- Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Sanaz Manteghi
- Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | | | - Benjamin Walker
- Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Masaya Baba
- International Research Centre for Medical Sciences, Kumamoto University, Kumamoto 860-0811, Japan
| | - Julie St-Pierre
- Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Vincent Giguère
- Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montréal, Quebec H3G 1Y6, Canada; International Research Centre for Medical Sciences, Kumamoto University, Kumamoto 860-0811, Japan; Department of Oncology, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Arnim Pause
- Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3A 1A3, Canada; Department of Biochemistry, McGill University, Montréal, Quebec H3G 1Y6, Canada
| |
Collapse
|
38
|
Lopategi A, López-Vicario C, Alcaraz-Quiles J, García-Alonso V, Rius B, Titos E, Clària J. Role of bioactive lipid mediators in obese adipose tissue inflammation and endocrine dysfunction. Mol Cell Endocrinol 2016; 419:44-59. [PMID: 26433072 DOI: 10.1016/j.mce.2015.09.033] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/18/2015] [Accepted: 09/28/2015] [Indexed: 12/14/2022]
Abstract
White adipose tissue is recognized as an active endocrine organ implicated in the maintenance of metabolic homeostasis. However, adipose tissue function, which has a crucial role in the development of obesity-related comorbidities including insulin resistance and non-alcoholic fatty liver disease, is dysregulated in obese individuals. This review explores the physiological functions and molecular actions of bioactive lipids biosynthesized in adipose tissue including sphingolipids and phospholipids, and in particular fatty acids derived from phospholipids of the cell membrane. Special emphasis is given to polyunsaturated fatty acids of the omega-6 and omega-3 families and their conversion to bioactive lipid mediators through the cyclooxygenase and lipoxygenase pathways. The participation of omega-3-derived lipid autacoids in the resolution of adipose tissue inflammation and in the prevention of obesity-associated hepatic complications is also thoroughly discussed.
Collapse
Affiliation(s)
- Aritz Lopategi
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, IDIBAPS, Barcelona 08036, Spain.
| | - Cristina López-Vicario
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, IDIBAPS, Barcelona 08036, Spain
| | - José Alcaraz-Quiles
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, IDIBAPS, Barcelona 08036, Spain
| | - Verónica García-Alonso
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, IDIBAPS, Barcelona 08036, Spain
| | - Bibiana Rius
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, IDIBAPS, Barcelona 08036, Spain
| | - Esther Titos
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, IDIBAPS, Barcelona 08036, Spain; CIBERehd, University of Barcelona, Barcelona 08036, Spain
| | - Joan Clària
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, IDIBAPS, Barcelona 08036, Spain; CIBERehd, University of Barcelona, Barcelona 08036, Spain; Department of Physiological Sciences I, University of Barcelona, Barcelona 08036, Spain.
| |
Collapse
|
39
|
Eichmann TO, Lass A. DAG tales: the multiple faces of diacylglycerol--stereochemistry, metabolism, and signaling. Cell Mol Life Sci 2015; 72:3931-52. [PMID: 26153463 PMCID: PMC4575688 DOI: 10.1007/s00018-015-1982-3] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/17/2015] [Accepted: 06/29/2015] [Indexed: 12/31/2022]
Abstract
The neutral lipids diacylglycerols (DAGs) are involved in a plethora of metabolic pathways. They function as components of cellular membranes, as building blocks for glycero(phospho)lipids, and as lipid second messengers. Considering their central role in multiple metabolic processes and signaling pathways, cellular DAG levels require a tight regulation to ensure a constant and controlled availability. Interestingly, DAG species are versatile in their chemical structure. Besides the different fatty acid species esterified to the glycerol backbone, DAGs can occur in three different stereo/regioisoforms, each with unique biological properties. Recent scientific advances have revealed that DAG metabolizing enzymes generate and distinguish different DAG isoforms, and that only one DAG isoform holds signaling properties. Herein, we review the current knowledge of DAG stereochemistry and their impact on cellular metabolism and signaling. Further, we describe intracellular DAG turnover and its stereochemistry in a 3-pool model to illustrate the spatial and stereochemical separation and hereby the diversity of cellular DAG metabolism.
Collapse
Affiliation(s)
- Thomas Oliver Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31/2, 8010, Graz, Austria.
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31/2, 8010, Graz, Austria.
| |
Collapse
|
40
|
Berger E, Héraud S, Mojallal A, Lequeux C, Weiss-Gayet M, Damour O, Géloën A. Pathways commonly dysregulated in mouse and human obese adipose tissue: FAT/CD36 modulates differentiation and lipogenesis. Adipocyte 2015; 4:161-80. [PMID: 26257990 DOI: 10.4161/21623945.2014.987578] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 10/06/2014] [Accepted: 11/10/2014] [Indexed: 12/25/2022] Open
Abstract
Obesity is linked to adipose tissue hypertrophy (increased adipocyte cell size) and hyperplasia (increased cell number). Comparative analyses of gene datasets allowed us to identify 1426 genes which may represent common adipose phenotype in humans and mice. Among them we identified several adipocyte-specific genes dysregulated in obese adipose tissue, involved in either fatty acid storage (acyl CoA synthase ACSL1, hormone-sensitive lipase LIPE, aquaporin 7 AQP7, perilipin PLIN) or cell adhesion (fibronectin FN1, collagens COL1A1, COL1A3, metalloprotein MMP9, or both (scavenger receptor FAT/CD36). Using real-time analysis of cell surface occupancy on xCELLigence system we developed a new method to study lipid uptake and differentiation of mouse 3T3L1 fibroblasts and human adipose stem cells. Both processes are regulated by insulin and fatty acids such as oleic acid. We showed that fatty acid addition to culture media increased the differentiation rate and was required for full differentiation into unilocular adipocytes. Significant activation of lipogenesis, i.e. lipid accumulation, by either insulin or oleic acid was monitored in times ranging from 1 to 24 h, depending on differentiation state, whereas significant effects on adipogenesis, i.e., surperimposed lipid accumulation and gene transcriptional regulations were measured after 3 to 4 d. Combination of selected times for analysis of lipid contents, cell counts, size fractionations, and gene transcriptional regulations showed that FAT/CD36 specific inhibitor AP5258 significantly increased cell survival of oleic acid-treated mouse and human adipocytes, and partially restored the transcriptional response to oleic acid in the presence of insulin through JNK pathway. Taken together, these data open new perspectives to study the molecular mechanisms commonly dysregulated in mouse and human obesity at the level of lipogenesis linked to hypertrophy and adipogenesis linked to hyperplasia.
Collapse
Key Words
- (h)ASCs, (human)adipose stem cells
- (h)dA, (human) adipocytes differentiated in vitro
- ACSL1, Acyl-CoA synthetase long chain family member 1
- AQP7, aquaporin 7
- BSA, bovine serum albumin, lipid-free
- CEBPA, CCAAT/enhancer binding protein (C/EBP) α
- CIDEA &
- CIDEC, cell death-inducing DFFA-like effectors a and c
- COL1A1 &
- COL1A3, Collagens 1 α
- DMEM, Dulbecco's Modified Eagle's Medium
- ECM, extracellular matrix
- FABP1 and 4, fatty acid binding proteins 1 and 4
- FAT/CD36, fatty acid translocase
- FCS, foetal calf serum
- FN1, fibronectin
- GO, Gene Ontology
- HSPG, heparan sulfate proteoglycans
- IBMX, isobutylmethylxanthine
- IL6, interleukin 6
- JNK, Jun-NH2 kinase
- LIPE, hormone-sensitive lipase
- MMP9, matrix metallopeptidase 9
- PBS, phosphate buffered saline
- PLIN, perilipin
- PPARG, peroxisome-proliferator receptor gamma
- RT-qPCR, real-time quantitative polymerase chain reaction
- RTCA, Real-time Cell Analyzer
- TA, adipose tissue
- TNFA, tumor necrosis factor α
- adipogenesis
- bFGF, basic fibroblast growth factor
- bio-informatics
- fatty acid
- lipogenesis
- obesity
- real-time cell analysis
- subunits 1 and 3
Collapse
|
41
|
Walker GE, Marzullo P, Ricotti R, Bona G, Prodam F. The pathophysiology of abdominal adipose tissue depots in health and disease. Horm Mol Biol Clin Investig 2015; 19:57-74. [PMID: 25390016 DOI: 10.1515/hmbci-2014-0023] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 12/22/2022]
Abstract
Obesity is currently the most important contributor to ill health and expenditure worldwide. More alarming is the fact that the pediatric population parallels adults, with obesity closely associated to type 2 diabetes mellitus (T2D), cardiovascular disease, hypertension, non-alcoholic fatty liver disease, vitamin D deficiency (VDD) and certain types of cancer. The observation in the early 1950s that android or truncal adipose tissue (AT) distribution compared to gynoid had a greater association with metabolic dysfunction, in particular T2D and cardiovascular disease risk, led to the hypothesis that obesity-associated complications are not associated with fat mass per se, but the pattern of fat distribution. This concept was further supported by groups of individuals with metabolic dysfunction despite a lean phenotype, and healthy obese people protected from metabolic dysfunction. It is now well recognized that an increase in visceral AT is an independent risk factor for the development of obesity-associated comorbidities with AT depot distribution, their anatomic, cellular and molecular features defining their role. The differences and the plasticity of subcutaneous, visceral and ectopic ATs to store and release fatty acids and to synthesize and secrete adipokines, defines the metabolic outcomes. The present review will examine the phenotypic and pathophysiological differences between the different AT depots, with a particular focus on the abdominal depots and their link to metabolic complications.
Collapse
|
42
|
Stelmanska E, Szrok S, Swierczynski J. Progesterone-induced down-regulation of hormone sensitive lipase (Lipe) and up-regulation of G0/G1 switch 2 (G0s2) genes expression in inguinal adipose tissue of female rats is reflected by diminished rate of lipolysis. J Steroid Biochem Mol Biol 2015; 147:31-9. [PMID: 25448749 DOI: 10.1016/j.jsbmb.2014.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 11/17/2014] [Accepted: 11/18/2014] [Indexed: 11/23/2022]
Abstract
Decreased lipolytic activity in adipose tissue may be one of the reasons behind excess accumulation of body fat during pregnancy. The aim of this study was to analyze the effect of progesterone on the expression of: (a) Lipe (encoding hormone-sensitive lipase, HSL), (b) Pnpla2 (encoding adipose triglyceride lipase, ATGL), (c) abhydrolase domain containing 5 (Abhd5), and (d) G0/G1 switch 2 (G0s2) genes in white adipose tissue (WAT), as potential targets for progesterone action during the course of pregnancy. Administration of progesterone to female rats, which was reflected by approximately 2.5-fold increase in circulating progesterone concentration, is associated with a decrease in Lipe gene expression in the inguinal WAT. The expression of Pnpla2 gene in all main fat depots of females and males remained unchanged after progesterone administration. Administration of progesterone resulted in an increase in the expression of Abhd5 gene (whose product increases ATGL activity) and G0s2 gene (whose product decreases ATGL activity) in the inguinal WAT of female rats. Mifepristone, a selective antagonist of progesterone receptor, abolished the effect of progesterone on Lipe, Abhd5 and G0s2 genes expression in the inguinal WAT. The decrease in Lipe and the increase in Abhd5 and G0s2 genes expression was associated with lower rate of stimulated lipolysis. Administration of progesterone exerted no effect on Lipe, Abhd5 and G0s2 genes expression and stimulated lipolysis in the retroperitoneal WAT of females, as well as in the inguinal, epididymal and retroperitoneal WAT of males. In conclusion, our findings suggest that progesterone decreases the rate of lipolysis in the inguinal WAT of female rats, inhibiting the activity of both ATGL (by stimulating synthesis of G0S2 - specific inhibitor of the enzyme) and HSL (due to inhibition of Lipe gene expression).
Collapse
Affiliation(s)
- Ewa Stelmanska
- Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland
| | - Sylwia Szrok
- Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland
| | - Julian Swierczynski
- Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland.
| |
Collapse
|
43
|
Magrone T, Jirillo E. Childhood obesity: immune response and nutritional approaches. Front Immunol 2015; 6:76. [PMID: 25759691 PMCID: PMC4338791 DOI: 10.3389/fimmu.2015.00076] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 02/09/2015] [Indexed: 12/15/2022] Open
Abstract
Childhood obesity is characterized by a low-grade inflammation status depending on the multicellular release of cytokines, adipokines, and reactive oxygen species. In particular, the imbalance between anti-inflammatory T regulatory cells and inflammatory T helper 17 cells seems to sustain such a phlogistic condition. Alterations of gut microbiota since childhood also contribute to the maintenance of inflammation. Therefore, besides preventive measures and caloric restrictions, dietary intake of natural products endowed with anti-oxidant and anti-inflammatory activities may represent a valid interventional approach for preventing and/or attenuating the pathological consequences of obesity. In this regard, the use of prebiotics, probiotics, polyphenols, polyunsaturated fatty acids, vitamins, and melatonin in human clinical trials will be described.
Collapse
Affiliation(s)
- Thea Magrone
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari , Bari , Italy
| | - Emilio Jirillo
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari , Bari , Italy
| |
Collapse
|
44
|
Fatty acid signaling: the new function of intracellular lipases. Int J Mol Sci 2015; 16:3831-55. [PMID: 25674855 PMCID: PMC4346929 DOI: 10.3390/ijms16023831] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 11/19/2014] [Accepted: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
Until recently, intracellular triacylglycerols (TAG) stored in the form of cytoplasmic lipid droplets have been considered to be only passive “energy conserves”. Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed.
Collapse
|
45
|
Gao X, van der Veen JN, Hermansson M, Ordoñez M, Gomez-Muñoz A, Vance DE, Jacobs RL. Decreased lipogenesis in white adipose tissue contributes to the resistance to high fat diet-induced obesity in phosphatidylethanolamine N-methyltransferase-deficient mice. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:152-62. [DOI: 10.1016/j.bbalip.2014.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/21/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
|
46
|
Amrutkar M, Cansby E, Nuñez-Durán E, Pirazzi C, Ståhlman M, Stenfeldt E, Smith U, Borén J, Mahlapuu M. Protein kinase STK25 regulates hepatic lipid partitioning and progression of liver steatosis and NASH. FASEB J 2015; 29:1564-76. [PMID: 25609431 DOI: 10.1096/fj.14-264937] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/08/2014] [Indexed: 12/21/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease, and 10% to 20% of NAFLD patients progress to nonalcoholic steatohepatitis (NASH). The molecular pathways controlling progression to NAFLD/NASH remain poorly understood. We recently identified serine/threonine protein kinase 25 (STK25) as a regulator of whole-body insulin and glucose homeostasis. This study investigates the role of STK25 in liver lipid accumulation and NASH. Stk25 transgenic mice challenged with a high-fat diet displayed a dramatic increase in liver steatosis and hepatic insulin resistance compared to wild-type siblings. Focal fibrosis, hepatocellular damage, and inflammation were readily seen in transgenic but not wild-type livers. Transgenic livers displayed reduced β-oxidation and triacylglycerol secretion, while lipid uptake and synthesis remained unchanged. STK25 was associated with lipid droplets, colocalizing with the main hepatic lipid droplet-coating protein adipose differentiation-related protein, the level of which was increased 3.8 ± 0.7-fold in transgenic livers (P < 0.01), while a key hepatic lipase, adipose triacylglycerol lipase, was translocated from the lipid droplets surface to the cytoplasm, providing the likely mechanism underlying the effect of STK25. In summary, STK25 is a lipid droplet-associated protein that promotes NAFLD through control of lipid release from the droplets for β-oxidation and triacylglycerol secretion. STK25 also drives pathogenesis of NASH.
Collapse
Affiliation(s)
- Manoj Amrutkar
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Emmelie Cansby
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Esther Nuñez-Durán
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Carlo Pirazzi
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Marcus Ståhlman
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Elin Stenfeldt
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Ulf Smith
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Jan Borén
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Margit Mahlapuu
- *Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, and Wallenberg Laboratory, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
47
|
Albert JS, Yerges-Armstrong LM, Horenstein RB, Pollin TI, Sreenivasan UT, Chai S, Blaner WS, Snitker S, O'Connell JR, Gong DW, Breyer RJ, Ryan AS, McLenithan JC, Shuldiner AR, Sztalryd C, Damcott CM. Null mutation in hormone-sensitive lipase gene and risk of type 2 diabetes. N Engl J Med 2014; 370:2307-2315. [PMID: 24848981 PMCID: PMC4096982 DOI: 10.1056/nejmoa1315496] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Lipolysis regulates energy homeostasis through the hydrolysis of intracellular triglycerides and the release of fatty acids for use as energy substrates or lipid mediators in cellular processes. Genes encoding proteins that regulate energy homeostasis through lipolysis are thus likely to play an important role in determining susceptibility to metabolic disorders. METHODS We sequenced 12 lipolytic-pathway genes in Old Order Amish participants whose fasting serum triglyceride levels were at the extremes of the distribution and identified a novel 19-bp frameshift deletion in exon 9 of LIPE, encoding hormone-sensitive lipase (HSL), a key enzyme for lipolysis. We genotyped the deletion in DNA from 2738 Amish participants and performed association analyses to determine the effects of the deletion on metabolic traits. We also obtained biopsy specimens of abdominal subcutaneous adipose tissue from 2 study participants who were homozygous for the deletion (DD genotype), 10 who were heterozygous (ID genotype), and 7 who were noncarriers (II genotype) for assessment of adipose histologic characteristics, lipolysis, enzyme activity, cytokine release, and messenger RNA (mRNA) and protein levels. RESULTS Carriers of the mutation had dyslipidemia, hepatic steatosis, systemic insulin resistance, and diabetes. In adipose tissue from study participants with the DD genotype, the mutation resulted in the absence of HSL protein, small adipocytes, impaired lipolysis, insulin resistance, and inflammation. Transcription factors responsive to peroxisome-proliferator-activated receptor γ (PPAR-γ) and downstream target genes were down-regulated in adipose tissue from participants with the DD genotype, altering the regulation of pathways influencing adipogenesis, insulin sensitivity, and lipid metabolism. CONCLUSIONS These findings indicate the physiological significance of HSL in adipocyte function and the regulation of systemic lipid and glucose homeostasis and underscore the severe metabolic consequences of impaired lipolysis. (Funded by the National Institutes of Health and others).
Collapse
Affiliation(s)
- Jessica S Albert
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Laura M Yerges-Armstrong
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Richard B Horenstein
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Toni I Pollin
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Urmila T Sreenivasan
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Sumbul Chai
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - William S Blaner
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Soren Snitker
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Jeffrey R O'Connell
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Da-Wei Gong
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Richard J Breyer
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Alice S Ryan
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - John C McLenithan
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Alan R Shuldiner
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Carole Sztalryd
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Coleen M Damcott
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| |
Collapse
|
48
|
Giordano A, Smorlesi A, Frontini A, Barbatelli G, Cinti S. White, brown and pink adipocytes: the extraordinary plasticity of the adipose organ. Eur J Endocrinol 2014; 170:R159-71. [PMID: 24468979 DOI: 10.1530/eje-13-0945] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In mammals, adipocytes are lipid-laden cells making up the parenchyma of the multi-depot adipose organ. White adipocytes store lipids for release as free fatty acids during fasting periods; brown adipocytes burn glucose and lipids to maintain thermal homeostasis. A third type of adipocyte, the pink adipocyte, has recently been characterised in mouse subcutaneous fat depots during pregnancy and lactation. Pink adipocytes are mammary gland alveolar epithelial cells whose role is to produce and secrete milk. Emerging evidence suggests that they derive from the transdifferentiation of subcutaneous white adipocytes. The functional response of the adipose organ to a range of metabolic and environmental challenges highlights its extraordinary plasticity. Cold exposure induces an increase in the 'brown' component of the organ to meet the increased thermal demand; in states of positive energy balance, the 'white' component expands to store excess nutrients; finally, the 'pink' component develops in subcutaneous depots during pregnancy to ensure litter feeding. At the cell level, plasticity is provided not only by stem cell proliferation and differentiation but also, distinctively, by direct transdifferentiation of fully differentiated adipocytes by the stimuli that induce genetic expression reprogramming and through it a change in phenotype and, consequently function. A greater understanding of adipocyte transdifferentiation mechanisms would have the potential to shed light on their biology as well as inspire novel therapeutic strategies against metabolic syndrome (browning) and breast cancer (pinking).
Collapse
MESH Headings
- Adipocytes, Brown/cytology
- Adipocytes, Brown/metabolism
- Adipocytes, Brown/pathology
- Adipocytes, White/cytology
- Adipocytes, White/metabolism
- Adipocytes, White/pathology
- Adipogenesis
- Animals
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cell Transdifferentiation
- Female
- Humans
- Lactation
- Lipid Metabolism
- Male
- Mammary Glands, Animal/cytology
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Glands, Human/cytology
- Mammary Glands, Human/metabolism
- Mammary Glands, Human/pathology
- Metabolic Syndrome/metabolism
- Metabolic Syndrome/pathology
- Obesity/metabolism
- Obesity/pathology
- Organ Specificity
- Pigmentation
- Pregnancy
- Sex Characteristics
- Subcutaneous Fat, Abdominal/cytology
- Subcutaneous Fat, Abdominal/metabolism
- Subcutaneous Fat, Abdominal/pathology
Collapse
Affiliation(s)
- Antonio Giordano
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy and
| | | | | | | | | |
Collapse
|
49
|
Wang QA, Scherer PE, Gupta RK. Improved methodologies for the study of adipose biology: insights gained and opportunities ahead. J Lipid Res 2014; 55:605-24. [PMID: 24532650 PMCID: PMC3966696 DOI: 10.1194/jlr.r046441] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 02/10/2014] [Indexed: 12/14/2022] Open
Abstract
Adipocyte differentiation and function have become areas of intense focus in the field of energy metabolism; however, understanding the role of specific genes in the establishment and maintenance of fat cell function can be challenging and complex. In this review, we offer practical guidelines for the study of adipocyte development and function. We discuss improved cellular and genetic systems for the study of adipose biology and highlight recent insights gained from these new approaches.
Collapse
Affiliation(s)
- Qiong A. Wang
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
| | - Philipp E. Scherer
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75287
| | - Rana K. Gupta
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
| |
Collapse
|
50
|
Giordano A, Murano I, Mondini E, Perugini J, Smorlesi A, Severi I, Barazzoni R, Scherer PE, Cinti S. Obese adipocytes show ultrastructural features of stressed cells and die of pyroptosis. J Lipid Res 2013; 54:2423-36. [PMID: 23836106 DOI: 10.1194/jlr.m038638] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We previously suggested that, in obese animals and humans, white adipose tissue inflammation results from the death of hypertrophic adipocytes; these are then cleared by macrophages, giving rise to distinctive structures we denominated crown-like structures. Here we present evidence that subcutaneous and visceral hypertrophic adipocytes of leptin-deficient (ob/ob and db/db) obese mice exhibit ultrastructural abnormalities (including calcium accumulation and cholesterol crystals), many of which are more common in hyperglycemic db/db versus normoglycemic ob/ob mice and in visceral versus subcutaneous depots. Degenerating adipocytes whose intracellular content disperses in the extracellular space were also noted in obese mice; in addition, increased anti-reactive oxygen species enzyme expression in obese fat pads, documented by RT-PCR and immunohistochemistry, suggests that ultrastructural changes are accompanied by oxidative stress. RT-PCR showed NLRP3 inflammasome activation in the fat pads of both leptin-deficient and high-fat diet obese mice, in which formation of active caspase-1 was documented by immunohistochemistry in the cytoplasm of several hypertrophic adipocytes. Notably, caspase-1 was not detected in FAT-ATTAC transgenic mice, where adipocytes die of apoptosis. Thus, white adipocyte overexpansion induces a stress state that ultimately leads to death. NLRP3-dependent caspase-1 activation in hypertrophic adipocytes likely induces obese adipocyte death by pyroptosis, a proinflammatory programmed cell death.
Collapse
Affiliation(s)
- Antonio Giordano
- Department of Experimental and Clinical Medicine, University of Ancona, Ancona, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|