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Demirel-Yalciner T, Cetinkaya B, Sozen E, Ozer NK. Impact of Seipin in cholesterol mediated lipid droplet maturation; status of endoplasmic reticulum stress and lipophagy. Mech Ageing Dev 2024; 219:111933. [PMID: 38588730 DOI: 10.1016/j.mad.2024.111933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 03/31/2024] [Accepted: 04/02/2024] [Indexed: 04/10/2024]
Abstract
The global prevalence of nonalcoholic fatty liver disease (NAFLD) defined by the increased number of lipid droplets (LDs) in hepatocytes, have risen continuously in parallel with the obesity. LDs and related proteins are known to affect cellular metabolism and signaling. Seipin, one of the most important LD-related proteins, plays a critical role in LD biogenesis. Although the role of adipose tissue-specific Seipin silencing is known, hepatocyte-specific silencing upon cholesterol-mediated lipid accumulation has not been investigated. In our study, we investigated the effect of Seipin on endoplasmic reticulum (ER) stress and lipophagy in cholesterol accumulated mouse hepatocyte cells. In this direction, cholesterol accumulation was induced by cholesterol-containing liposome, while Seipin mRNA and protein levels were reduced by siRNA. Our findings show that cholesterol containing liposome administration in hepatocytes increases both Seipin protein and number of large LDs. However Seipin silencing reduced the increase of cholesterol mediated large LDs and Glucose-regulated protein 78 (GRP78) mRNA. Additionally, lysosome-LD colocalization increased only in cells treated with cholesterol containing liposome, while the siRNA against Seipin did not lead any significant difference. According to our findings, we hypothesize that Seipin silencing in hepatocytes reduced cholesterol mediated LD maturation as well as GRP78 levels, but not lipophagy.
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Affiliation(s)
- Tugce Demirel-Yalciner
- Department of Biochemistry, Faculty of Medicine, Uskudar University, Istanbul 34662, Turkey; Department of Biochemistry, Faculty of Medicine, Marmara University, Maltepe, Istanbul 34854, Turkey; Metabolic and Inflammatory Diseases Research Center (METIFLAM), Uskudar University, Istanbul 34662, Turkey
| | - Bengu Cetinkaya
- Department of Biochemistry, Faculty of Medicine, Marmara University, Maltepe, Istanbul 34854, Turkey
| | - Erdi Sozen
- Department of Biochemistry, Faculty of Medicine, Marmara University, Maltepe, Istanbul 34854, Turkey; Genetic and Metabolic Diseases Research Center (GEMHAM), Marmara University, Maltepe, Istanbul 34854, Turkey
| | - Nesrin Kartal Ozer
- Department of Biochemistry, Faculty of Medicine, Uskudar University, Istanbul 34662, Turkey; Metabolic and Inflammatory Diseases Research Center (METIFLAM), Uskudar University, Istanbul 34662, Turkey.
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2
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Cobelo-Gómez S, Sánchez-Iglesias S, Rábano A, Senra A, Aguiar P, Gómez-Lado N, García-Varela L, Burgueño-García I, Lampón-Fernández L, Fernández-Pombo A, Díaz-López EJ, Prado-Moraña T, San Millán B, Araújo-Vilar D. A murine model of BSCL2-associated Celia's encephalopathy. Neurobiol Dis 2023; 187:106300. [PMID: 37717662 DOI: 10.1016/j.nbd.2023.106300] [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: 06/03/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 09/19/2023] Open
Abstract
Celia's encephalopathy or progressive encephalopathy with/without lipodystrophy is a neurodegenerative disease with a fatal prognosis in childhood. It is generally caused by the c.985C > T variant in the BSCL2 gene, leading to the skipping of exon 7 and resulting in an aberrant seipin protein (Celia-seipin). To precisely define the temporal evolution and the mechanisms involved in neurodegeneration, lipodystrophy and fatty liver in Celia's encephalopathy, our group has generated the first global knock-in murine model for the aberrant human transcript of BSCL2 (Bscl2Celia/Celia) using a strategy based on the Cre/loxP recombination system. In order to carry out a characterization at the neurological, adipose tissue and hepatic level, behavioral studies, brain PET, metabolic, histological and molecular studies were performed. Around 12% of homozygous and 5.4% of heterozygous knock-in mice showed severe neurological symptoms early in life, and their life expectancy was dramatically reduced. Severe generalized lipodystrophy and mild hepatic steatosis were present in these affected animals, while serum triglycerides and glucose metabolism were normal, with no insulin resistance. Furthermore, the study revealed a reduction in brain glucose uptake, along with patchy loss of Purkinje cells and the presence of intranuclear inclusions in cerebellar cortex cells. Homozygous, non-severely-affected knock-in mice showed a decrease in locomotor activity and greater anxiety compared with their wild type littermates. Bscl2Celia/Celia is the first murine model of Celia's encephalopathy which partially recapitulates the phenotype and severe neurodegenerative picture suffered by these patients. This model will provide a helpful tool to investigate both the progressive encephalopathy with/without lipodystrophy and congenital generalized lipodystrophy.
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Affiliation(s)
- Silvia Cobelo-Gómez
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain
| | - Sofía Sánchez-Iglesias
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain
| | - Alberto Rábano
- Alzheimer's Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer Center, Madrid, Spain
| | - Ana Senra
- Department of Physiology, CIMUS, University of Santiago de Compostela, Spain
| | - Pablo Aguiar
- Molecular Imaging and Medical Physics, University of Santiago de Compostela-IDIS, Spain; Nuclear Medicine and Molecular Imaging Group, IDIS, University Clinical Hospital of Santiago de Compostela, Spain
| | - Noemí Gómez-Lado
- Molecular Imaging and Medical Physics, University of Santiago de Compostela-IDIS, Spain; Nuclear Medicine and Molecular Imaging Group, IDIS, University Clinical Hospital of Santiago de Compostela, Spain
| | - Lara García-Varela
- Molecular Imaging and Medical Physics, University of Santiago de Compostela-IDIS, Spain; Nuclear Medicine and Molecular Imaging Group, IDIS, University Clinical Hospital of Santiago de Compostela, Spain
| | - Iván Burgueño-García
- Alzheimer's Disease Research Unit, CIEN Foundation, Queen Sofia Foundation Alzheimer Center, Madrid, Spain
| | - Laura Lampón-Fernández
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain
| | - Antía Fernández-Pombo
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain
| | - Everardo Josué Díaz-López
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain
| | - Teresa Prado-Moraña
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain
| | - Beatriz San Millán
- Grupo de Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IISGS), Vigo, Spain; Pathology Department, Alvaro Cunqueiro Hospital, Vigo, Spain
| | - David Araújo-Vilar
- UETeM-Molecular Pathology Group. Department of Psychiatry, Radiology, Public Health, Nursing and Medicine, IDIS-CIMUS, University of Santiago de Compostela, Spain; Division of Endocrinology and Nutrition, University Clinical Hospital of Santiago de Compostela, Spain.
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3
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Sommer N, Roumane A, Han W, Delibegović M, Rochford JJ, Mcilroy GD. Gene therapy restores adipose tissue and metabolic health in a pre-clinical mouse model of lipodystrophy. Mol Ther Methods Clin Dev 2022; 27:206-216. [PMID: 36320417 PMCID: PMC9589143 DOI: 10.1016/j.omtm.2022.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 09/29/2022] [Indexed: 11/29/2022]
Abstract
Congenital generalized lipodystrophy type 2 is a serious multisystem disorder with limited treatment options. It is caused by mutations affecting the BSCL2 gene, which encodes the protein seipin. Patients with congenital generalized lipodystrophy type 2 lack both metabolic and mechanical adipose tissue and develop severe metabolic complications including hepatic steatosis, lipoatrophic diabetes, and cardiovascular disease. Gene therapies are becoming viable treatments, helping to alleviate inherited and acquired human disorders. We aimed to determine whether gene therapy could offer an effective form of medical intervention for lipodystrophy. We examined whether systemic adeno-associated virus delivery of human BSCL2 could reverse metabolic disease in seipin knockout mice, where white adipose tissue is absent. We reveal that adeno-associated virus gene therapy targets adipose progenitor cells in vivo and substantially restores white adipose tissue development in adult seipin knockout mice. This resulted in both rapid and prolonged beneficial effects to metabolic health in this pre-clinical mouse model of congenital generalized lipodystrophy type 2. Hyperglycemia was normalized within 2 weeks post-treatment together with normalization of severe insulin resistance. We propose that gene therapy offers great potential as a therapeutic strategy to correct multiple metabolic complications in patients with congenital lipodystrophy.
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Affiliation(s)
- Nadine Sommer
- The Rowett Institute, University of Aberdeen, Aberdeen AB25 2ZD, UK
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Ahlima Roumane
- The Rowett Institute, University of Aberdeen, Aberdeen AB25 2ZD, UK
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, Australia
| | - Weiping Han
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A∗STAR), 138667 Singapore, Singapore
- Center for Neuro-Metabolism and Regeneration Research, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510700, China
- School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Mirela Delibegović
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Justin J. Rochford
- The Rowett Institute, University of Aberdeen, Aberdeen AB25 2ZD, UK
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - George D. Mcilroy
- The Rowett Institute, University of Aberdeen, Aberdeen AB25 2ZD, UK
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK
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Li Y, Yang X, Peng L, Xia Q, Zhang Y, Huang W, Liu T, Jia D. Role of Seipin in Human Diseases and Experimental Animal Models. Biomolecules 2022; 12:biom12060840. [PMID: 35740965 PMCID: PMC9221541 DOI: 10.3390/biom12060840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 02/05/2023] Open
Abstract
Seipin, a protein encoded by the Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) gene, is famous for its key role in the biogenesis of lipid droplets and type 2 congenital generalised lipodystrophy (CGL2). BSCL2 gene mutations result in genetic diseases including CGL2, progressive encephalopathy with or without lipodystrophy (also called Celia’s encephalopathy), and BSCL2-associated motor neuron diseases. Abnormal expression of seipin has also been found in hepatic steatosis, neurodegenerative diseases, glioblastoma stroke, cardiac hypertrophy, and other diseases. In the current study, we comprehensively summarise phenotypes, underlying mechanisms, and treatment of human diseases caused by BSCL2 gene mutations, paralleled by animal studies including systemic or specific Bscl2 gene knockout, or Bscl2 gene overexpression. In various animal models representing diseases that are not related to Bscl2 mutations, differential expression patterns and functional roles of seipin are also described. Furthermore, we highlight the potential therapeutic approaches by targeting seipin or its upstream and downstream signalling pathways. Taken together, restoring adipose tissue function and targeting seipin-related pathways are effective strategies for CGL2 treatment. Meanwhile, seipin-related pathways are also considered to have potential therapeutic value in diseases that are not caused by BSCL2 gene mutations.
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Affiliation(s)
- Yuying Li
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Xinmin Yang
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Linrui Peng
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China; (L.P.); (Y.Z.)
| | - Qing Xia
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Yuwei Zhang
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China; (L.P.); (Y.Z.)
| | - Wei Huang
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
- Institutes for Systems Genetics & Immunology and Inflammation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (W.H.); (T.L.)
| | - Tingting Liu
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
- Correspondence: (W.H.); (T.L.)
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy and Collaborative Innovation Center of Biotherapy, Sichuan University, Chengdu 610041, China;
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5
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Magré J, Prieur X. Seipin Deficiency as a Model of Severe Adipocyte Dysfunction: Lessons from Rodent Models and Teaching for Human Disease. Int J Mol Sci 2022; 23:740. [PMID: 35054926 PMCID: PMC8775404 DOI: 10.3390/ijms23020740] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 02/05/2023] Open
Abstract
Obesity prevalence is increasing worldwide, leading to cardiometabolic morbidities. Adipocyte dysfunction, impairing white adipose tissue (WAT) expandability and metabolic flexibility, is central in the development of obesity-related metabolic complications. Rare syndromes of lipodystrophy characterized by an extreme paucity of functional adipose tissue should be considered as primary adipocyte dysfunction diseases. Berardinelli-Seip congenital lipodystrophy (BSCL) is the most severe form with a near absence of WAT associated with cardiometabolic complications such as insulin resistance, liver steatosis, dyslipidemia, and cardiomyopathy. Twenty years ago, mutations in the BSCL2 gene have been identified as the cause of BSCL in human. BSCL2 encodes seipin, an endoplasmic reticulum (ER) anchored protein whose function was unknown back then. Studies of seipin knockout mice or rats demonstrated how seipin deficiency leads to severe lipodystrophy and to cardiometabolic complications. At the cellular levels, seipin is organized in multimers that are particularly enriched at ER/lipid droplet and ER/mitochondria contact sites. Seipin deficiency impairs both adipocyte differentiation and mature adipocyte maintenance. Experiments using adipose tissue transplantation in seipin knockout mice and tissue-specific deletion of seipin have provided a large body of evidence that liver steatosis, cardiomyopathy, and renal injury, classical diabetic complications, are all consequences of lipodystrophy. Rare adipocyte dysfunctions such as in BSCL are the key paradigm to unravel the pathways that control adipocyte homeostasis. The knowledge gathered through the study of these pathologies may bring new strategies to maintain and improve adipose tissue expandability.
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Affiliation(s)
| | - Xavier Prieur
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, L’institut du Thorax, Université de Nantes, F-44000 Nantes, France;
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6
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Le Lay S, Magré J, Prieur X. Not Enough Fat: Mouse Models of Inherited Lipodystrophy. Front Endocrinol (Lausanne) 2022; 13:785819. [PMID: 35250856 PMCID: PMC8895270 DOI: 10.3389/fendo.2022.785819] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/17/2022] [Indexed: 12/19/2022] Open
Abstract
Lipodystrophies belong to the heterogenous group of syndromes in which the primary defect is a generalized or partial absence of adipose tissue, which may be congenital or acquired in origin. Lipodystrophy should be considered in patients manifesting the combination of insulin resistance (with or without overt diabetes), dyslipidemia and fatty liver. Lipodystrophies are classified according to the etiology of the disease (genetic or acquired) and to the anatomical distribution of adipose tissue (generalized or partial). The mechanism of adipose tissue loss is specific to each syndrome, depending on the biological function of the mutated gene. Mice models, together with cellular studies have permitted clarification of the mechanisms by which human mutations deeply compromise adipocyte homeostasis. In addition, rodent models have proven to be crucial in deciphering the cardiometabolic consequences of the lack of adipose tissue such as NAFLD, muscle insulin resistance and cardiomyopathy. More precisely, tissue-specific transgenic and knockout mice have brought new tools to distinguish phenotypic traits that are the consequences of lipodystrophy from those that are cell-autonomous. In this review, we discuss the mice models of lipodystrophy including those of inherited human syndromes of generalized and partial lipodystrophy. We present how these models have demonstrated the central role of white adipose tissue in energetic homeostasis in general, including insulin sensitivity and lipid handling in particular. We underscore the differences reported with the human phenotype and discuss the limit of rodent models in recapitulating adipose tissue primary default. Finally, we present how these mice models have highlighted the function of the causative-genes and brought new insights into the pathophysiology of the cardiometabolic complications associated with lipodystrophy.
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Affiliation(s)
- Soazig Le Lay
- Nantes Université, CNRS, INSERM, l’institut du thorax, Nantes, France
- Univ Angers, SFR ICAT, Angers, France
| | - Jocelyne Magré
- Nantes Université, CNRS, INSERM, l’institut du thorax, Nantes, France
| | - Xavier Prieur
- Nantes Université, CNRS, INSERM, l’institut du thorax, Nantes, France
- *Correspondence: Xavier Prieur,
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Alliouachene S, Kieswich JE, Bilanges B, McCafferty K, Thiemermann C, Vanhaesebroeck B, Yaqoob MM. Uninephrectomy and class II PI3K-C2β inactivation synergistically protect against obesity, insulin resistance and liver steatosis in mice. Am J Transplant 2021; 21:2688-2697. [PMID: 33370494 DOI: 10.1111/ajt.16470] [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: 09/17/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 01/25/2023]
Abstract
Uninephrectomy (UNx) in living kidney donors for transplantation is now routine clinical practice. While chronic kidney disease, due to bilateral kidney dysfunction, is associated with insulin resistance, liver steatosis, and type 2 diabetes, the metabolic impact of UNx remains unclear. To better understand the crosstalk between the kidney and insulin target tissues, we studied the metabolic consequences of UNx and the potential involvement of class II PI3K-C2β, the inactivation of which has been reported to result in insulin sensitization. Mice underwent UNx or sham operation followed by either normal chow or high-fat diet (HFD). Seventeen weeks post-UNx, mice showed improved glucose tolerance, insulin sensitivity, and decreased HFD-induced liver steatosis. This was associated with an enhanced serum FGF21 and insulin-stimulated Akt signaling in the liver and muscle of both lean and obese mice. Remarkably, the combination of UNx and PI3K-C2β inactivation protected against HFD-induced obesity and further potentiated the metabolic improvement observed in WT UNx mice correlating with a synergistic increase in metabolic tissues of (1) insulin-stimulated Akt signaling (2) FGFR1 and βKlotho expression. We demonstrated a potential beneficial effect of kidney donation and more effectively with PI3K-C2β inactivation to protect against metabolic disorders through a mutual insulin/FGF21 sensitization.
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Affiliation(s)
- Samira Alliouachene
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Julius E Kieswich
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | | | - Kieran McCafferty
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Christoph Thiemermann
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | | | - Muhammad M Yaqoob
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
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Wu X, Liu X, Wang H, Zhou Z, Yang C, Li Z, Zhang Y, Shi X, Zhang L, Wang Y, Xian X, Liu G, Huang W. Seipin Deficiency Accelerates Heart Failure Due to Calcium Handling Abnormalities and Endoplasmic Reticulum Stress in Mice. Front Cardiovasc Med 2021; 8:644128. [PMID: 33778025 PMCID: PMC7990891 DOI: 10.3389/fcvm.2021.644128] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/15/2021] [Indexed: 12/19/2022] Open
Abstract
Seipin deficiency can induce hypertrophic cardiomyopathy and heart failure, which often leads to death in humans. To explore the effects and the possible mechanisms of Seipin deficiency in myocardial remodeling, Seipin knockout (SKO) mice underwent transverse aortic constriction (TAC) for 12 weeks. We found a more severe left ventricular hypertrophy and diastolic heart failure and increases in inflammatory cell infiltration, collagen deposition, and apoptotic bodies in the SKO group compared to those in the wild type (WT) group after TAC. Electron microscopy also showed a more extensive sarcoplasmic reticulum expansion, deformation of microtubules, and formation of mitochondrial lesions in the cardiomyocytes of SKO mice than in those of WT mice after TAC. Compared with the WT group, the SKO group showed increases in endoplasmic reticulum (ER) stress-, inflammation-, and fibrosis-related gene expression, while calcium ion-related factors, such as Serca2a and Ryr, were decreased in the SKO group after TAC. Increased levels of the ER stress-related protein GRP78 and decreased SERCA2a and P-RYR protein levels were detected in the SKO group compared with the WT group after TAC. Slowing of transient Ca2+ current decay and an increased SR Ca2+ content in myocytes were detected in the cardiomyocytes of SKO mice. Adipose tissue transplantation could not rescue the cardiac hypertrophy after TAC in SKO mice. In conclusion, we found that Seipin deficiency could promote cardiac hypertrophy and diastolic heart failure after TAC in mice. These changes may be related to the impairment of myocardial calcium handling, ER stress, inflammation, and apoptosis.
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Affiliation(s)
- Xiaoyue Wu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xuejing Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Huan Wang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Zihao Zhou
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Chengzhi Yang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Zijian Li
- Institute of Vascular Medicine, Peking University Third Hospital, Beijing, China
| | - Youyi Zhang
- Institute of Vascular Medicine, Peking University Third Hospital, Beijing, China
| | - XiaoLu Shi
- Experimental Research Center, China Academy of Chinese Medical Science, Beijing, China
| | - Ling Zhang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Yuhui Wang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xunde Xian
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - George Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Wei Huang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
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McGrath C, Little-Letsinger SE, Sankaran JS, Sen B, Xie Z, Styner MA, Zong X, Chen W, Rubin J, Klett EL, Coleman RA, Styner M. Exercise Increases Bone in SEIPIN Deficient Lipodystrophy, Despite Low Marrow Adiposity. Front Endocrinol (Lausanne) 2021; 12:782194. [PMID: 35145475 PMCID: PMC8822583 DOI: 10.3389/fendo.2021.782194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/20/2021] [Indexed: 01/12/2023] Open
Abstract
Exercise, typically beneficial for skeletal health, has not yet been studied in lipodystrophy, a condition characterized by paucity of white adipose tissue, with eventual diabetes, and steatosis. We applied a mouse model of global deficiency of Bscl2 (SEIPIN), required for lipid droplet formation. Male twelve-week-old B6 knockouts (KO) and wild type (WT) littermates were assigned six-weeks of voluntary, running exercise (E) versus non-exercise (N=5-8). KO weighed 14% less than WT (p=0.01) and exhibited an absence of epididymal adipose tissue; KO liver Plin1 via qPCR was 9-fold that of WT (p=0.04), consistent with steatosis. Bone marrow adipose tissue (BMAT), unlike white adipose, was measurable, although 40.5% lower in KO vs WT (p=0.0003) via 9.4T MRI/advanced image analysis. SEIPIN ablation's most notable effect marrow adiposity was in the proximal femoral diaphysis (-56% KO vs WT, p=0.005), with relative preservation in KO-distal-femur. Bone via μCT was preserved in SEIPIN KO, though some quality parameters were attenuated. Running distance, speed, and time were comparable in KO and WT. Exercise reduced weight (-24% WT-E vs WT p<0.001) but not in KO. Notably, exercise increased trabecular BV/TV in both (+31%, KO-E vs KO, p=0.004; +14%, WT-E vs WT, p=0.006). The presence and distribution of BMAT in SEIPIN KO, though lower than WT, is unexpected and points to a uniqueness of this depot. That trabecular bone increases were achievable in both KO and WT, despite a difference in BMAT quantity/distribution, points to potential metabolic flexibility during exercise-induced skeletal anabolism.
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Affiliation(s)
- Cody McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Sarah E. Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jeyantt Srinivas Sankaran
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Buer Sen
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zhihui Xie
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Martin A. Styner
- Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Xiaopeng Zong
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Janet Rubin
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
| | - Eric L. Klett
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Rosalind A. Coleman
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Maya Styner
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- *Correspondence: Maya Styner,
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10
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Hoa Chung L, Qi Y. Lipodystrophy - A Rare Condition with Serious Metabolic Abnormalities. Rare Dis 2020. [DOI: 10.5772/intechopen.88667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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11
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Zhou H, Xu C, Lee H, Yoon Y, Chen W. Berardinelli-Seip congenital lipodystrophy 2/SEIPIN determines brown adipose tissue maintenance and thermogenic programing. Mol Metab 2020; 36:100971. [PMID: 32246911 PMCID: PMC7136632 DOI: 10.1016/j.molmet.2020.02.014] [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: 12/25/2019] [Revised: 02/18/2020] [Accepted: 02/25/2020] [Indexed: 01/12/2023] Open
Abstract
Objective Understanding the mechanisms that control brown adipose tissue (BAT) mass and functionality is crucial for our understanding of how the disruption of energy homeostasis leads to obesity. Bernerdinali Seip Congenital Lipodystrophy (BSCL) type 2 (BSCL2, a.k.a. SEIPIN), a lipodystrophy-associated protein, has been shown to not be required for brown adipogenesis, but it has been shown to be essential for perinatal BAT development. However, its role in mature BAT maintenance and thermogenic programing remains poorly understood. Methods We subjected Bscl2f/f and Bscl2UCP1-BKO (BKO) mice with a brown adipose-specific loss of BSCL2 through UCP1 promoter-driven Cre to environmental, pharmacological and diet interventions to challenge BAT functionality and reprogramming. We carried out physiological, molecular and transcriptomic analyses of BAT. Results The deletion of BSCL2 in mature brown adipocytes increased sympathetic nervous system-independent cAMP/protein kinase A (PKA) signaling in BAT. Such activation reduced BAT triglyceride content and mass and was sufficient to reduce plasma triglyceride, but not enough to combat thermoneutral and high fat diet-induced obesity. Surprisingly, BKO mice displayed an impaired response to acute and chronic cold challenges despite cAMP/PKA activation. When subjected to chronic cold exposure or the administration of a β3-adrenergic agonist, CL 316,243, BKO mice failed to induce BAT recruitment and underwent dramatic brown adipocyte loss. Transcriptomic analysis revealed pathological BAT remodeling with inflammation and fibrosis, which was further exacerbated by a chronic thermogenic challenge in BKO mice. Mechanistically, we found abnormal mitochondrial shapes and function in BAT of BKO mice housed at 21 °C; as well as mitochondrial DNA depletion and necroptotic-mediated brown adipocyte death after chronic thermogenic insult. Conclusion BSCL2-mediated lipid catabolism within BAT is crucial for mature brown adipocyte function and survival both during times of activation and quiescence. BSCL2 is an important regulator of mature brown adipocyte mitochondrial metabolism, necroptosis and thus adaptive thermogenesis. Mature BAT-specific loss of BSCL2 (Bscl2UCP1-BKO) activates SNS-independent cAMP/PKA signaling. Bscl2UCP1-BKO increases BAT mitochondrial fission and uncoupling. Bscl2UCP1-BKO reduces plasma triglyceride but not adiposity under thermoneutrality or high fat diet. Bscl2UCP1-BKO blunts BAT reprograming and causes cold intolerance. BSCL2 deletion exposes brown adipocyte to necroptosis under chronic thermogenic stress.
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Affiliation(s)
- Hongyi Zhou
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Cheng Xu
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Hakjoo Lee
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Yisang Yoon
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
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12
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Xiong J, Sun P, Wang Y, Hua X, Song W, Wang Y, Wu J, Yu W, Liu G, Chen L. Heterozygous deletion of Seipin in islet beta cells of male mice has an impact on insulin synthesis and secretion through reduced PPARγ expression. Diabetologia 2020; 63:338-350. [PMID: 31776610 DOI: 10.1007/s00125-019-05038-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/03/2019] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) is an autosomal recessive disorder characterised by lipodystrophy and insulin resistance. BSCL2 is caused by loss-of-function mutations in the Seipin gene (also known as Bscl2). Deletion of this gene in mice induces insulin resistance, glucose intolerance and a loss of adipose tissue. This study evaluated the effects of genetic deletion of Seipin on islet beta cell function. METHODS We examined seipin expression in islet cells and measured glucose profiles, insulin synthesis, glucose-stimulated insulin secretion (GSIS), islet expression of peroxisome proliferator-activated receptor γ (PPARγ), levels of Pdx-1, Nkx6.1, Glut2 (also known as Slc2a2) and proinsulin mRNA, nuclear translocation of pancreatic duodenal homeobox 1 (PDX-1), islet numbers, and beta cell mass and proliferation in male and female Seipin-knockout homozygous (Seipin-/-) and heterozygous (Seipin+/-) mice. RESULTS Male and female Seipin-/- mice displayed glucose intolerance, insulin resistance, hyperinsulinaemia and a lack of adipose tissue. By contrast, male but not female Seipin+/- mice showed glucose intolerance without adipose tissue loss or insulin resistance. Seipin was highly expressed in islet beta cells in wild-type mice. Expression of islet PPARγ was reduced in male Seipin-/- and Seipin+/- mice but not in female Seipin-/- or Seipin+/- mice. Treatment of male Seipin+/- mice with rosiglitazone corrected the glucose intolerance. Male Seipin+/- mice displayed a decrease in islet insulin concentration and GSIS with low expression of Pdx-1, Nkx6.1, Glut2 and proinsulin, and a decline in PDX-1 nuclear translocation; these changes were rescued by rosiglitazone administration. Male Seipin-/- mice showed obvious, but rosiglitazone-sensitive, increases in islet insulin concentration, islet number and beta cell mass and proliferation, with a notable decline in GSIS. Ovariectomised female Seipin+/- mice displayed glucose intolerance and deficits in insulin synthesis and secretion, with a decline in islet PPARγ level; these deleterious effects were reversed by administration of oestradiol or rosiglitazone. CONCLUSIONS/INTERPRETATION Heterozygous deletion of Seipin in islet beta cells impacts on insulin synthesis and secretion through reduced PPARγ expression. This leads to glucose intolerance and is relieved by oestradiol, which rescues PPARγ expression.
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Affiliation(s)
- Jianwei Xiong
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Peng Sun
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, China
| | - Ya Wang
- Department of Physiology, Nanjing Medical University, Longmian Road 101, Nanjing, 211166, China
| | - Xu Hua
- Department of Physiology, Nanjing Medical University, Longmian Road 101, Nanjing, 211166, China
| | - Wenyu Song
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, China
| | - Yan Wang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, China
| | - Jie Wu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Wenfeng Yu
- Key Laboratory of Medical Molecular Biology, Guizhou Medical University, Guiyang, 550004, China.
| | - George Liu
- Institute of Cardiovascular Sciences, Peking University and Key Laboratory of Cardiovascular Sciences, China Administration of Education, Beijing, 100191, China.
| | - Ling Chen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.
- Department of Physiology, Nanjing Medical University, Longmian Road 101, Nanjing, 211166, China.
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13
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Mcilroy GD, Mitchell SE, Han W, Delibegović M, Rochford JJ. Ablation of Bscl2/seipin in hepatocytes does not cause metabolic dysfunction in congenital generalised lipodystrophy. Dis Model Mech 2020; 13:dmm.042655. [PMID: 31848133 PMCID: PMC6994952 DOI: 10.1242/dmm.042655] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 12/10/2019] [Indexed: 12/19/2022] Open
Abstract
Mutations affecting the BSCL2 gene cause the most severe form of congenital generalised lipodystrophy (CGL). Affected individuals develop severe metabolic complications including diabetes and hepatic steatosis. Bscl2-deficient mice almost entirely reproduce the CGL phenotype. Adipose tissue-specific loss of Bscl2 is also sufficient to cause early-onset generalised lipodystrophy in mice. However, these mice do not show severe metabolic dysfunction, even when challenged with a high-fat diet. Germline Bscl2 loss in mice and BSCL2 disruption in humans causes severe hepatic steatosis, and the encoded protein, seipin, has acknowledged roles in lipid accumulation. Given the critical role of the liver in glucose regulation, we speculated that intact hepatic Bscl2 expression may protect adipose tissue-specific Bscl2-deficient mice from metabolic disease. To investigate this, we generated a novel mouse model in which Bscl2 has been deleted in both adipose tissue and hepatocytes simultaneously using an adeno-associated viral vector. Despite achieving efficient disruption of Bscl2 in the liver, hepatic lipid accumulation and metabolic homeostasis was unaffected in mice fed a high-fat diet for 4 weeks. We also investigated the consequences of BSCL2 ablation in the human hepatocyte HepG2 cell line using CRISPR/Cas9 genome editing. No significant increases in lipid accumulation were observed in BSCL2 knockout cell lines. Overall, we reveal that Bscl2/BSCL2 does not appear to play a cell-autonomous role in the regulation of lipid accumulation in the liver. Loss of hepatic BSCL2 is therefore unlikely to contribute significantly to the development of hepatic steatosis or metabolic dysfunction in this form of CGL. Editor's choice: Hepatic Bscl2 ablation in adipose tissue-specific Bscl2 knockout mice does not cause metabolic dysfunction. CRISPR/Cas9 genome editing reveals that seipin does not play a cell-autonomous role in regulating hepatocyte lipid accumulation.
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Affiliation(s)
- George D Mcilroy
- The Rowett Institute, University of Aberdeen, Aberdeen AB25 2ZD, UK .,Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Sharon E Mitchell
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
| | - Weiping Han
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore 138667
| | - Mirela Delibegović
- Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK.,Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Justin J Rochford
- The Rowett Institute, University of Aberdeen, Aberdeen AB25 2ZD, UK.,Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Aberdeen AB25 2ZD, UK
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14
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Enhanced postprandial glucagon-like peptide-1 secretion during obesity development has a protective role against glucose intolerance induction in rats. Br J Nutr 2019; 122:411-422. [PMID: 31352909 DOI: 10.1017/s0007114519001223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is an incretin hormone that regulates postprandial glycaemic response by enhancing insulin secretion. We previously demonstrated that the postprandial GLP-1 response was enhanced during the development of diet-induced obesity in rats. However, the physiological relevance of the enhanced GLP-1 response remained unclear. We aimed to determine the role of endogenous GLP-1 during obesity development. Male Sprague-Dawley rats were given either a control diet or a high-fat/high-sucrose (HFS, 30 % fat and 40 % sucrose, weight basis) diet with or without continuous administration of the GLP-1 receptor antagonist, exendin (9-39) (Ex9, 100 µg/d), for 5 weeks. Meal tolerance tests (MTT) were performed to assess postprandial glucose, insulin and GLP-1 responses to a liquid diet administration (15 kcal (63 kJ)/10 ml per kg body weight) every 2 weeks. The AUC of postprandial glucose in the HFS group was similar to the control group in both MTT (P = 0·9665 and P = 0·3475, respectively), whereas AUC of postprandial GLP-1 (after 4 weeks,P = 0·0457) and of insulin (after 2 and 4 weeks, P = 0·0486 and P = 0·0110) was higher in the HFS group compared with the control group. In the Ex9 group, AUC of postprandial glucose (P = 0·0297 and P = 0·0486) was higher along with a lower insulin response compared with the HFS group (P = 0·0564 and P = 0·0281). These results suggest that enhancement of the postprandial GLP-1 response during obesity development has a role in maintaining a normal postprandial glycaemic response. Hence, enhancing endogenous GLP-1 secretion by certain materials could be a potential target for prevention of glucose intolerance.
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15
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Ren YA, Monkkonen T, Lewis MT, Bernard DJ, Christian HC, Jorgez CJ, Moore JA, Landua JD, Chin HM, Chen W, Singh S, Kim IS, Zhang XH, Xia Y, Phillips KJ, MacKay H, Waterland RA, Ljungberg MC, Saha PK, Hartig SM, Coll TF, Richards JS. S100a4-Cre-mediated deletion of Patched1 causes hypogonadotropic hypogonadism: role of pituitary hematopoietic cells in endocrine regulation. JCI Insight 2019; 5:126325. [PMID: 31265437 DOI: 10.1172/jci.insight.126325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hormones produced by the anterior pituitary gland regulate an array of important physiological functions, but pituitary hormone disorders are not fully understood. Herein we report that genetically-engineered mice with deletion of the hedgehog signaling receptor Patched1 by S100a4 promoter-driven Cre recombinase (S100a4-Cre;Ptch1fl/fl mutants) exhibit adult-onset hypogonadotropic hypogonadism and multiple pituitary hormone disorders. During the transition from puberty to adult, S100a4-Cre;Ptch1fl/fl mice of both sexes develop hypogonadism coupled with reduced gonadotropin levels. Their pituitary glands also display severe structural and functional abnormalities, as revealed by transmission electron microscopy and expression of key genes regulating pituitary endocrine functions. S100a4-Cre activity in the anterior pituitary gland is restricted to CD45+ cells of hematopoietic origin, including folliculo-stellate cells and other immune cell types, causing sex-specific changes in the expression of genes regulating the local microenvironment of the anterior pituitary. These findings provide in vivo evidence for the importance of pituitary hematopoietic cells in regulating fertility and endocrine function, in particular during sexual maturation and likely through sexually dimorphic mechanisms. These findings support a previously unrecognized role of hematopoietic cells in causing hypogonadotropic hypogonadism and provide inroads into the molecular and cellular basis for pituitary hormone disorders in humans.
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Affiliation(s)
- Yi Athena Ren
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | | | - Michael T Lewis
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Department of Radiology and.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, England
| | - Carolina J Jorgez
- Department of Urology, Baylor College of Medicine, Houston, Texas, USA
| | - Joshua A Moore
- Department of Urology, Baylor College of Medicine, Houston, Texas, USA
| | - John D Landua
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Department of Radiology and.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Haelee M Chin
- Department of Biology, Rice University, Houston, Texas, USA
| | - Weiqin Chen
- Department of Physiology, Augusta University, Augusta, Georgia, USA
| | - Swarnima Singh
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Ik Sun Kim
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Xiang Hf Zhang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Yan Xia
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Kevin J Phillips
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Harry MacKay
- USDA/ARS Children's Nutrition Research Center, Houston, Texas, USA
| | | | - M Cecilia Ljungberg
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Jan and Dan Duncan Neurological Research Center at Texas Children's Hospital, Houston, Texas, USA
| | - Pradip K Saha
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Sean M Hartig
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Tatiana Fiordelisio Coll
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, University of Montpellier, Montpellier, France.,Laboratorio de Neuroendocrinología Comparada, Departamento de Ecología y Recursos Naturales, Biología, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, México City, Distrito Federal, México
| | - JoAnne S Richards
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
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16
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Xu W, Zhou H, Xuan H, Saha P, Wang G, Chen W. Novel metabolic disorders in skeletal muscle of Lipodystrophic Bscl2/Seipin deficient mice. Mol Cell Endocrinol 2019; 482:1-10. [PMID: 30521848 PMCID: PMC6340772 DOI: 10.1016/j.mce.2018.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/03/2018] [Accepted: 12/03/2018] [Indexed: 01/23/2023]
Abstract
Bscl2-/- mice recapitulate many of the major metabolic manifestations in Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) individuals, including lipodystrophy, hepatosteatosis, muscular hypertrophy, and insulin resistance. Metabolic defects in Bscl2-/- mice with regard to glucose and lipid metabolism in skeletal muscle have never been investigated. Here, we identified Bscl2-/- mice displayed reduced intramyocellular triglyceride (IMTG) content but increased glycogen storage predominantly in oxidative type I soleus muscle (SM). These changes were associated with increased incomplete fatty acid oxidation and glycogen synthesis. Interestingly, SM in Bscl2-/- mice demonstrated a fasting duration induced insulin sensitivity which was further confirmed by hyperinsulinemic-euglycemic clamp in SM of overnight fasted Bscl2-/- mice but reversed by raising circulating NEFA levels through intralipid infusion. Furthermore, mice with skeletal muscle-specific inactivation of BSCL2 manifested no changes in muscle deposition of lipids and glycogen, suggesting BSCL2 does not play a cell-autonomous role in muscle lipid and glucose homeostasis. Our study uncovers a novel link between muscle metabolic defects and insulin resistance, and underscores an important role of circulating NEFA in regulating oxidative muscle insulin signaling in BSCL2 lipodystrophy.
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Affiliation(s)
- Wenqiong Xu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, PR China; Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA
| | - Hongyi Zhou
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA
| | - Hongzhuan Xuan
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA; School of Life Science, Liaocheng University, Liaocheng, Shandong Province, 252059, PR China
| | - Pradip Saha
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Gongxian Wang
- Department of Urology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, PR China.
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA.
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17
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Wang H, Xu PF, Li JY, Liu XJ, Wu XY, Xu F, Xie BC, Huang XM, Zhou ZH, Kayoumu A, Liu G, Huang W. Adipose tissue transplantation ameliorates lipodystrophy-associated metabolic disorders in seipin-deficient mice. Am J Physiol Endocrinol Metab 2019; 316:E54-E62. [PMID: 30457912 DOI: 10.1152/ajpendo.00180.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Seipin deficiency is responsible for type 2 congenital generalized lipodystrophy with severe loss of adipose tissue and can lead to hepatic steatosis, insulin resistance (IR), and dyslipidemia in humans. Adipose tissue secretes many adipokines that are central to the regulation of metabolism. In this study, we investigated whether transplantation of normal adipose tissue could ameliorate severe hepatic steatosis, IR, and dyslipidemia in lipoatrophic seipin knockout (SKO) mice. Normal adipose tissue from wild-type mice was transplanted into 6-wk-old SKO mice. At 4 mo after adipose tissue transplantation (AT), the transplanted fat survived with detectable blood vessels, and the reduced levels of plasma leptin, a major adipokine, were dramatically increased. Severe hepatic steatosis, IR, and dyslipidemia in SKO mice were ameliorated after AT. In addition, abnormal hepatic lipogenesis and β-oxidation gene expression in SKO mice were improved after AT. Our results suggest that AT may be an effective treatment to improve lipodystrophy-associated metabolic disorders.
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Affiliation(s)
- Huan Wang
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University , Beijing , China
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Peng-Fei Xu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
- Institute of Military Training Related Medical Science of PLA, 150th Central Hospital of PLA , Luoyang, Henan , China
| | - Jing-Yi Li
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Xue-Jing Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Xiao-Yue Wu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Fang Xu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Bei-Chen Xie
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Xiao-Min Huang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Zi-Hao Zhou
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Abudurexiti Kayoumu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - George Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
| | - Wei Huang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Ministry of Education, Peking University Health Science Center , Beijing , China
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18
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Female adipose tissue-specific Bscl2 knockout mice develop only moderate metabolic dysfunction when housed at thermoneutrality and fed a high-fat diet. Sci Rep 2018; 8:17863. [PMID: 30552349 PMCID: PMC6294754 DOI: 10.1038/s41598-018-36078-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/12/2018] [Indexed: 02/04/2023] Open
Abstract
Mutations affecting the BSCL2 gene cause the most severe form of congenital generalised lipodystrophy. Affected individuals almost completely lack adipose tissue and suffer from severe diabetes and metabolic complications. Likewise, mice lacking Bscl2 in all tissues have dramatically reduced adipose mass, glucose intolerance and hyperinsulinaemia. However, male adipose tissue-specific Bscl2 knockout mice fail to develop the metabolic dysfunction observed in Bscl2 null mice and BSCL2 deficient patients, despite a similar generalised lack of adipose tissues. Clinical reports indicate gender differences frequently exist in cases of lipodystrophy, with female patients more adversely affected than male patients. We therefore generated and characterised female mice lacking Bscl2 specifically in adipose tissue (Ad-B2(−/−)). We show that female Ad-B2(−/−) mice also develop early-onset lipodystrophy when fed a chow diet and are maintained under standard housing conditions (21 °C) or thermoneutrality (30 °C). Despite this, female Ad-B2(−/−) mice fail to develop severe metabolic dysfunction. Only when female Ad-B2(−/−) mice are maintained at thermoneutrality and fed a high-fat diet do subtle alterations to metabolic homeostasis manifest. This is despite a striking inability to expand adipose mass. Our findings provide further evidence that loss of Bscl2 in non-adipose tissues may contribute to the severity of metabolic dysfunction in this condition.
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19
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Exploring Seipin: From Biochemistry to Bioinformatics Predictions. Int J Cell Biol 2018; 2018:5207608. [PMID: 30402103 PMCID: PMC6192094 DOI: 10.1155/2018/5207608] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/12/2018] [Accepted: 09/03/2018] [Indexed: 01/30/2023] Open
Abstract
Seipin is a nonenzymatic protein encoded by the BSCL2 gene. It is involved in lipodystrophy and seipinopathy diseases. Named in 2001, all seipin functions are still far from being understood. Therefore, we reviewed much of the research, trying to find a pattern that could explain commonly observed features of seipin expression disorders. Likewise, this review shows how this protein seems to have tissue-specific functions. In an integrative view, we conclude by proposing a theoretical model to explain how seipin might be involved in the triacylglycerol synthesis pathway.
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Mcilroy GD, Suchacki K, Roelofs AJ, Yang W, Fu Y, Bai B, Wallace RJ, De Bari C, Cawthorn WP, Han W, Delibegović M, Rochford JJ. Adipose specific disruption of seipin causes early-onset generalised lipodystrophy and altered fuel utilisation without severe metabolic disease. Mol Metab 2018; 10:55-65. [PMID: 29459250 PMCID: PMC5985228 DOI: 10.1016/j.molmet.2018.01.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/16/2018] [Accepted: 01/23/2018] [Indexed: 11/29/2022] Open
Abstract
Objective Mutations to the BSCL2 gene disrupt the protein seipin and cause the most severe form of congenital generalised lipodystrophy (CGL). Affected individuals exhibit a near complete loss of white adipose tissue (WAT) and suffer from metabolic disease. Seipin is critical for adipocyte development in culture and mice with germline disruption to Bscl2 recapitulate the effects of BSCL2 disruption in humans. Here we examined whether loss of Bscl2 specifically in developing adipocytes in vivo is sufficient to prevent adipose tissue development and cause all features observed with congenital BSCL2 disruption. Methods We generated and characterised a novel mouse model of Bscl2 deficiency in developing adipocytes (Ad-B2(−/−)) using the adipose-specific Adiponectin-Cre line. Results We demonstrate that Ad-B2(−/−) mice display early onset lipodystrophy, in common with congenital Bscl2 null mice and CGL2 patients. However, glucose intolerance, insulin resistance, and severe hepatic steatosis are not apparent. Food intake and energy expenditure are unchanged, but Ad-B2(−/−) mice exhibit significantly altered substrate utilisation. We also find differential effects of seipin loss between specific adipose depots revealing new insights regarding their varied characteristics. When fed a high-fat diet, Ad-B2(−/−) mice entirely fail to expand adipose mass but remain glucose tolerant. Conclusions Our findings demonstrate that disruption of Bscl2 specifically in developing adipocytes is sufficient to cause the early-onset generalised lipodystrophy observed in patients with mutations in BSCL2. However, this significant reduction in adipose mass does not cause the overt metabolic dysfunction seen in Bscl2 knockout mice, even following a high-fat diet challenge. Seipin loss only in developing adipocytes drives severe early-onset lipodystrophy. This leads to significantly altered use of metabolic substrates. We uncover developmental differences between poorly characterised adipose depots. Despite severely reduced adipose mass mice do not show overt metabolic disease.
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Affiliation(s)
| | - Karla Suchacki
- The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Anke J Roelofs
- Institute of Medical Sciences, University of Aberdeen, UK
| | - Wulin Yang
- Cancer Hospital and Anhui Province Key Laboratory of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Anhui, China
| | - Yanyun Fu
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Bo Bai
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Robert J Wallace
- Department of Orthopaedics, University of Edinburgh, Edinburgh, UK
| | - Cosimo De Bari
- Institute of Medical Sciences, University of Aberdeen, UK
| | - William P Cawthorn
- The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Weiping Han
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore
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Siddiqah IM, Manandhar SP, Cocca SM, Hsueh T, Cervantes V, Gharakhanian E. Yeast ENV9 encodes a conserved lipid droplet (LD) short-chain dehydrogenase involved in LD morphology. Curr Genet 2017; 63:1053-1072. [PMID: 28540421 DOI: 10.1007/s00294-017-0702-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/24/2017] [Accepted: 05/05/2017] [Indexed: 12/31/2022]
Abstract
Lipid droplets (LDs) have emerged as dynamic and interactive organelles with important roles in lipid metabolism and membrane biogenesis. Here, we report that Saccharomyces cerevisiae Env9 is a novel conserved oxidoreductase involved in LD morphology. Microscopic and biochemical studies confirm localization of tagged Env9 to LDs and implicate its C-terminal hydrophobic domain (aa241-265) in its membrane association and stability. Confocal studies reveal a role for Env9 in LD morphology. Env9 positively affects both formation of large LDs upon overexpression and LD proliferation under poor carbon source. In silico bioinformatic and modeling approaches establish that ENV9 is a widely conserved member of the short-chain dehydrogenase (SDR) superfamily. Bayesian phylogenetic studies strongly support ENV9 as an ortholog of human SDR retinol dehydrogenase 12 (RDH12). Dehydrogenase activity of Env9 was confirmed by in vitro oxidoreductase assays. RDH12 mutations have been linked to Leber Congenital Amaurosis. Similar site-directed point mutations in the predicted Env9 oxidoreductase active site (N146L) or cofactor-binding site (G23-24A) abolished its reductase activity in vitro, consistent with those reported in other retinol dehydrogenases. The same residues were essential for affecting LD size and number in vivo. Taken together, our results implicate oxidoreductase activity of Env9 in its cellular role in LD morphology.
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Affiliation(s)
- Ikha M Siddiqah
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840, USA
| | - Surya P Manandhar
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840, USA
| | - Stephanie M Cocca
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840, USA
| | - Teli Hsueh
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840, USA
| | - Vanessa Cervantes
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840, USA
| | - Editte Gharakhanian
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA, 90840, USA.
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Sankella S, Garg A, Agarwal AK. Activation of Sphingolipid Pathway in the Livers of Lipodystrophic Agpat2-/- Mice. J Endocr Soc 2017; 1:980-993. [PMID: 29264548 PMCID: PMC5686665 DOI: 10.1210/js.2017-00157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/15/2017] [Indexed: 12/26/2022] Open
Abstract
A several fold increase in triacylglycerol is observed in the livers of lipodystrophic Agpat2−/− mice. We have previously reported an unexpected increase in the phosphatidic acid (PA) levels in the livers of these mice and that a few specific molecular species of PA were able to transcriptionally upregulate hepatic gluconeogenesis. In the current study, we measured the metabolites and expression of associated enzymes of the sphingolipid synthesis pathway. The entire sphingolipid pathway was activated both at the gene expression and the metabolite level. The levels of some ceramides were increased by as much as ~eightfold in the livers of Agpat2−/− mice. Furthermore, several molecular species of ceramides were increased in the plasma of Agpat2−/− mice, specifically ceramide C16:0, which was threefold elevated in the plasma of both the sexes. However, the ceramides failed to increase glucose production in mouse primary hepatocytes obtained from wild-type and Agpat2−/− mice, further establishing the specificity of PA in the induction of hepatic gluconeogenesis. This study shows elevated levels of sphingolipids in the steatotic livers of Agpat2−/− mice and increased expression of associated enzymes for the sphingolipid pathway. Therefore, this study and those in the literature suggest that ceramide C16:0 could be used as a biomarker for insulin resistance/type 2 diabetes mellitus.
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Affiliation(s)
- Shireesha Sankella
- Division of Nutrition and Metabolic Diseases, University of Texas Southwestern Medical Center, Dallas, Texas 75390.,Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Abhimanyu Garg
- Division of Nutrition and Metabolic Diseases, University of Texas Southwestern Medical Center, Dallas, Texas 75390.,Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Anil K Agarwal
- Division of Nutrition and Metabolic Diseases, University of Texas Southwestern Medical Center, Dallas, Texas 75390.,Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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Joubert M, Jagu B, Montaigne D, Marechal X, Tesse A, Ayer A, Dollet L, Le May C, Toumaniantz G, Manrique A, Charpentier F, Staels B, Magré J, Cariou B, Prieur X. The Sodium-Glucose Cotransporter 2 Inhibitor Dapagliflozin Prevents Cardiomyopathy in a Diabetic Lipodystrophic Mouse Model. Diabetes 2017; 66:1030-1040. [PMID: 28052965 DOI: 10.2337/db16-0733] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 12/16/2016] [Indexed: 12/18/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a well-recognized independent risk factor for heart failure. T2DM is associated with altered cardiac energy metabolism, leading to ectopic lipid accumulation and glucose overload, the exact contribution of these two parameters remaining unclear. To provide new insight into the mechanism driving the development of diabetic cardiomyopathy, we studied a unique model of T2DM: lipodystrophic Bscl2-/- (seipin knockout [SKO]) mice. Echocardiography and cardiac magnetic resonance imaging revealed hypertrophic cardiomyopathy with left ventricular dysfunction in SKO mice, and these two abnormalities were strongly correlated with hyperglycemia. Surprisingly, neither intramyocardial lipid accumulation nor lipotoxic hallmarks were detected in SKO mice. [18F]Fludeoxyglucose positron emission tomography showed increased myocardial glucose uptake. Consistently, the O-GlcNAcylated protein levels were markedly increased in an SKO heart, suggesting a glucose overload. To test this hypothesis, we treated SKO mice with the hypoglycemic sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin and the insulin sensitizer pioglitazone. Both treatments reduced the O-GlcNAcylated protein levels in SKO mice, and dapagliflozin successfully prevented the development of hypertrophic cardiomyopathy. Our data demonstrate that glucotoxicity by itself can trigger cardiac dysfunction and that a glucose-lowering agent can correct it. This result will contribute to better understanding of the potential cardiovascular benefits of SGLT2 inhibitors.
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Affiliation(s)
- Michael Joubert
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
- Endocrinologie, CHU Caen, Caen, France
- EA 4650, UNICAEN, GIP Cyceron, Caen, France
| | - Benoît Jagu
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - David Montaigne
- Universite Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Xavier Marechal
- Universite Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Angela Tesse
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Audrey Ayer
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Lucile Dollet
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Cédric Le May
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Gilles Toumaniantz
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | | | | | - Bart Staels
- Universite Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1011-European Genomic Institute for Diabetes, Lille, France
| | - Jocelyne Magré
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Bertrand Cariou
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, CHU Nantes, Nantes, France
| | - Xavier Prieur
- L'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
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Hepatic BSCL2 (Seipin) Deficiency Disrupts Lipid Droplet Homeostasis and Increases Lipid Metabolism via SCD1 Activity. Lipids 2016; 52:129-150. [DOI: 10.1007/s11745-016-4210-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022]
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Seipin deficiency alters brown adipose tissue thermogenesis and insulin sensitivity in a non-cell autonomous mode. Sci Rep 2016; 6:35487. [PMID: 27748422 PMCID: PMC5066230 DOI: 10.1038/srep35487] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 09/30/2016] [Indexed: 01/15/2023] Open
Abstract
Loss-of-function mutations in BSCL2 are responsible for Berardinelli-Seip congenital lipodystrophy, a rare disorder characterized by near absence of adipose tissue associated with insulin resistance. Seipin-deficient (Bscl2−/−) mice display an almost total loss of white adipose tissue (WAT) with residual brown adipose tissue (BAT). Previous cellular studies have shown that seipin deficiency alters white adipocyte differentiation. In this study, we aimed to decipher the consequences of seipin deficiency in BAT. Using a brown adipocyte cell-line, we show that seipin knockdown had very little effect on adipocyte differentiation without affecting insulin sensitivity and oxygen consumption. However, when submitted to cold acclimation or chronic β3 agonist treatment, Bscl2−/− mice displayed altered thermogenic capacity, despite several signs of BAT remodeling. Under cold activation, Bscl2−/− mice were able to maintain their body temperature when fed ad libitum, but not under short fasting. At control temperature (i.e. 21 °C), fasting worsened Bscl2−/− BAT properties. Finally, Bscl2−/− BAT displayed obvious signs of insulin resistance. Our results in these lipodystrophic mice strongly suggest that BAT activity relies on WAT as an energetic substrate provider and adipokine-producing organ. Therefore, the WAT/BAT dialogue is a key component of BAT integrity in guaranteeing its response to insulin and cold-activated adrenergic signals.
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Berardinelli-Seip Congenital Lipodystrophy 2/Seipin Is Not Required for Brown Adipogenesis but Regulates Brown Adipose Tissue Development and Function. Mol Cell Biol 2016; 36:2027-38. [PMID: 27185876 DOI: 10.1128/mcb.01120-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/08/2016] [Indexed: 01/08/2023] Open
Abstract
Brown adipose tissue (BAT) plays a unique role in regulating whole-body energy homeostasis by dissipating energy through thermogenic uncoupling. Berardinelli-Seip congenital lipodystrophy (BSCL) type 2 (BSCL2; also known as seipin) is a lipodystrophy-associated endoplasmic reticulum membrane protein essential for white adipocyte differentiation. Whether BSCL2 directly participates in brown adipocyte differentiation, development, and function, however, is unknown. We show that BSCL2 expression is increased during brown adipocyte differentiation. Its deletion does not impair the classic brown adipogenic program but rather induces premature activation of differentiating brown adipocytes through cyclic AMP (cAMP)/protein kinase A (PKA)-mediated lipolysis and fatty acid and glucose oxidation, as well as uncoupling. cAMP/PKA signaling is physiologically activated during neonatal BAT development in wild-type mice and greatly potentiated in mice with genetic deletion of Bscl2 in brown progenitor cells, leading to reduced BAT mass and lipid content during neonatal brown fat formation. However, prolonged overactivation of cAMP/PKA signaling during BAT development ultimately causes apoptosis of brown adipocytes through inflammation, resulting in BAT atrophy and increased overall adiposity in adult mice. These findings reveal a key cell-autonomous role for BSCL2 in controlling BAT mass/activity and provide novel insights into therapeutic strategies targeting cAMP/PKA signaling to regulate brown adipocyte function, viability, and metabolic homeostasis.
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Adipose tissue deficiency results in severe hyperlipidemia and atherosclerosis in the low-density lipoprotein receptor knockout mice. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:410-8. [PMID: 26921684 DOI: 10.1016/j.bbalip.2016.02.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/11/2016] [Accepted: 02/23/2016] [Indexed: 12/17/2022]
Abstract
Adipose tissue can store over 50% of whole-body cholesterol; however, the physiological role of adipose tissue in cholesterol metabolism and atherogenesis has not been directly assessed. Here, we examined lipoprotein metabolism and atherogenesis in a unique mouse model of severe lipodystrophy: the Seipin(-/-) mice, and also in mice deficient in both low-density lipoprotein receptor (Ldlr) and Seipin: the Ldlr(-/-)Seipin(-/-) mice. Plasma cholesterol was moderately increased in the Seipin(-/-) mice when fed an atherogenic diet. Strikingly, plasma cholesterol reached ~6000 mg/dl in the Seipin(-/-)Ldlr(-/-) mice on an atherogenic diet, as compared to ~1000 mg/dl in the Ldlr(-/-) mice on the same diet. The Seipin(-/-)Ldlr(-/-) mice also developed spontaneous atherosclerosis on chow diet and severe atherosclerosis on an atherogenic diet. Rosiglitazone treatment significantly reduced the hypercholesterolemia of the Seipin(-/-)Ldlr(-/-) mice, and also alleviated the severity of atherosclerosis. Our results provide direct evidence, for the first time, that the adipose tissue plays a critical role in the clearance of plasma cholesterol. Our results also reveal a previously unappreciated strong link between adipose tissue and LDLR in plasma cholesterol metabolism.
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Xu P, Wang H, Kayoumu A, Wang M, Huang W, Liu G. Diet rich in Docosahexaenoic Acid/Eicosapentaenoic Acid robustly ameliorates hepatic steatosis and insulin resistance in seipin deficient lipodystrophy mice. Nutr Metab (Lond) 2015; 12:58. [PMID: 26690553 PMCID: PMC4683947 DOI: 10.1186/s12986-015-0054-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 12/11/2015] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND N-3 polyunsaturated fatty acids (n-3 PUFAs), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been shown to effectively improve hepatic steatosis and insulin resistance caused by obesity. Lipodystrophy could also develop insulin resistance and hepatic steatosis. However, the effect of supplemental DHA/EPA to hepatic steatosis caused by lipodystrophy is unknown. In this study, we investigated whether a diet rich in n-3 PUFAs could ameliorate severe steatosis in lipoatrophic seipin gene knockout (SKO) mice. METHODS Eight-week-old C57BL/6 J WT and SKO mice were fed with normal chow diet (NC), or 2 % DHA/EPA (3:1) diet for 12 weeks. Total cholesterol (TC) and triglycerides (TG) in plasma and liver, plasma high density lipoprotein-cholesterol (HDL-C), glucose (Glu), insulin, leptin and adiponectin levels were measured. Gene regulations and protein levels were investigated using quantitative PCR and western blot in liver. RESULTS We found that the DHA/EPA diet protected against hepatic steatosis effectively in SKO mice morphologically. Hepatic TG content was decreased about 40 % (p < 0.05) in SKO mice fed with the DHA/EPA diet compared to chow fed SKO controls. Glucose and insulin tolerance were also improved significantly in SKO mice with DHA/EPA diet. In analyzing hepatic gene expression pattern it was found that TG synthesis related genes, such as carbohydrate response element binding protein (ChREBP), stearoyl-CoA desaturase 1 (SCD1) and fatty acid synthase (Fas) were upregulated in SKO mice compared to WT mice but were significantly decreased in SKO mice on DHA/EPA diet. Fatty acid β-oxidation related genes, on the other hand, such as peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase (CPT) and acyl-CoA oxidase 1 (ACOX1) were elevated in both WT and SKO groups on DHA/EPA diets. The protein levels of PPARα, SCD1, CPT1α, Insulin receptor substrate 1 (IRS1) and ratio of p-AKT to AKT showed the same tendency as the result of genes expressions. CONCLUSIONS The results suggest that n-3 PUFAs rich diet ameliorates lipodystrophy-induced hepatic steatosis through reducing TG synthesis, improving insulin resistance and enhancing β-oxidation in SKO mice.
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Affiliation(s)
- Pengfei Xu
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People’s Republic of China
| | - Huan Wang
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People’s Republic of China
| | - Abudurexiti Kayoumu
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People’s Republic of China
| | - Mengyu Wang
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People’s Republic of China
| | - Wei Huang
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People’s Republic of China
| | - George Liu
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People’s Republic of China
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Abstract
Congenital generalized lipodystrophy (CGL) is a heterogeneous autosomal recessive disorder characterized by a near complete lack of adipose tissue from birth and, later in life, the development of metabolic complications, such as diabetes mellitus, hypertriglyceridaemia and hepatic steatosis. Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations. The products of these genes have crucial roles in phospholipid and triglyceride synthesis, as well as in the formation of lipid droplets and caveolae within adipocytes. The predominant cause of metabolic complications in CGL is excess triglyceride accumulation in the liver and skeletal muscle owing to the inability to store triglycerides in adipose tissue. Profound hypoleptinaemia further exacerbates metabolic derangements by inducing a voracious appetite. Patients require psychological support, a low-fat diet, increased physical activity and cosmetic surgery. Aside from conventional therapy for hyperlipidaemia and diabetes mellitus, metreleptin replacement therapy can dramatically improve metabolic complications in patients with CGL. In this Review, we discuss the molecular genetic basis of CGL, the pathogenesis of the disease's metabolic complications and therapeutic options for patients with CGL.
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Affiliation(s)
- Nivedita Patni
- Division of Paediatric Endocrinology, Department of Paediatrics, Department of Internal Medicine, Centre for Human Nutrition, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8537, USA
| | - Abhimanyu Garg
- Division of Nutrition and Metabolic Diseases, Department of Internal Medicine, Center for Human Nutrition, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8537, USA
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Zhou H, Lei X, Benson T, Mintz J, Xu X, Harris RB, Weintraub NL, Wang X, Chen W. Berardinelli-Seip congenital lipodystrophy 2 regulates adipocyte lipolysis, browning, and energy balance in adult animals. J Lipid Res 2015; 56:1912-25. [PMID: 26269358 DOI: 10.1194/jlr.m060244] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Indexed: 11/20/2022] Open
Abstract
Mutations in BSCL2/SEIPIN cause Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2), but the mechanisms whereby Bscl2 regulates adipose tissue function are unclear. Here, we generated adipose tissue (mature) Bscl2 knockout (Ad-mKO) mice, in which Bscl2 was specifically ablated in adipocytes of adult animals, to investigate the impact of acquired Bscl2 deletion on adipose tissue function and energy balance. Ad-mKO mice displayed reduced adiposity and were protected against high fat diet-induced obesity, but not insulin resistance or hepatic steatosis. Gene expression profiling and biochemical assays revealed increased lipolysis and fatty acid oxidation in white adipose tissue (WAT) and brown adipose tissue , as well as browning of WAT, owing to induction of cAMP/protein kinase A signaling upon Bscl2 deletion. Interestingly, Bscl2 deletion reduced food intake and downregulated adipose β3-adrenergic receptor (ADRB3) expression. Impaired ADRB3 signaling partially offsets upregulated browning-induced energy expenditure and thermogenesis in Ad-mKO mice housed at ambient temperature. However, this counter-regulatory response was abrogated under thermoneutral conditions, resulting in even greater body mass loss in Ad-mKO mice. These findings suggest that Bscl2 regulates adipocyte lipolysis and β-adrenergic signaling to produce complex effects on adipose tissues and whole-body energy balance.
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Affiliation(s)
- Hongyi Zhou
- Department of Physiology, Georgia Regents University, Augusta, GA 30912
| | - Xinnuo Lei
- Department of Physiology, Georgia Regents University, Augusta, GA 30912
| | - Tyler Benson
- Vascular Biology Center, Georgia Regents University, Augusta, GA 30912
| | - James Mintz
- Vascular Biology Center, Georgia Regents University, Augusta, GA 30912
| | - Xiaojing Xu
- Georgia Prevention Institute, Department of Pediatrics, Georgia Regents University, Augusta, GA 30912
| | - Ruth B Harris
- Department of Physiology, Georgia Regents University, Augusta, GA 30912
| | - Neal L Weintraub
- Vascular Biology Center, Georgia Regents University, Augusta, GA 30912
| | - Xiaoling Wang
- Georgia Prevention Institute, Department of Pediatrics, Georgia Regents University, Augusta, GA 30912
| | - Weiqin Chen
- Department of Physiology, Georgia Regents University, Augusta, GA 30912
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Wang M, Gao M, Liao J, Han Y, Wang Y, Liu G. Dysfunction of lipid metabolism in lipodystrophic Seipin-deficient mice. Biochem Biophys Res Commun 2015; 461:206-10. [PMID: 25866184 DOI: 10.1016/j.bbrc.2015.03.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 03/22/2015] [Indexed: 01/17/2023]
Abstract
Congenital generalized lipodystrophy (CGL) is characterized by a complete loss of body adipose tissue accompanying dyslipidemia, severe hepatic steatosis and insulin resistance. However, the mechanisms of dyslipidemia and hepatic steatosis are unclear. Here using the lipodystrophic Seipin-deficient mouse (Seipin(-/-)) model, we found Seipin(-/-) mice were unable to respond appropriately to a long time fasting and developed postprandial hypertriglyceridemia. Impaired very low density lipoprotein (VLDL) secretion and enhanced triglyceride-rich lipoproteins (TRL) clearance were also observed in our Seipin(-/-) mice. To identify the association between upregulation of hepatic LDL receptor and enhanced TRL clearance, we crossed Seipin(-/-) mice with Ldlr(-/-) mice to generate Seipin(-/-)Ldlr(-/-) mice. Seipin(-/-)Ldlr(-/-) mice displayed increased TRL clearance only after 24 h-fast rather 6 h-fast. In contrast to Seipin(-/-) mice, Seipin(-/-)Ldlr(-/-) mice displayed hypertriglyceridemia as observed in human CGL patients. Furthermore, in this study, we demonstrated hepatic steatosis in lipodystrophy Seipin(-/-) mice is a metabolic adaptation of dysfunctional adipose tissue. This study using lipodystrophic model established the importance of adipose tissue in energy homeostasis and lipid metabolism.
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Affiliation(s)
- Mengyu Wang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing 100191, China
| | - Mingming Gao
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing 100191, China
| | - Jiawei Liao
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing 100191, China
| | - Yingchun Han
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing 100191, China
| | - Yuhui Wang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing 100191, China
| | - George Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing 100191, China.
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Xu P, Wang H, Kayoumu A, Wang M, Huang W, Liu G. Diet rich in Docosahexaenoic Acid/Eicosapentaenoic Acid robustly ameliorates hepatic steatosis and insulin resistance in seipin deficient lipodystrophy mice. Nutr Metab (Lond) 2015. [PMID: 26690553 DOI: 10.1186/sl2986-015-0054-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023] Open
Abstract
BACKGROUND N-3 polyunsaturated fatty acids (n-3 PUFAs), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been shown to effectively improve hepatic steatosis and insulin resistance caused by obesity. Lipodystrophy could also develop insulin resistance and hepatic steatosis. However, the effect of supplemental DHA/EPA to hepatic steatosis caused by lipodystrophy is unknown. In this study, we investigated whether a diet rich in n-3 PUFAs could ameliorate severe steatosis in lipoatrophic seipin gene knockout (SKO) mice. METHODS Eight-week-old C57BL/6 J WT and SKO mice were fed with normal chow diet (NC), or 2 % DHA/EPA (3:1) diet for 12 weeks. Total cholesterol (TC) and triglycerides (TG) in plasma and liver, plasma high density lipoprotein-cholesterol (HDL-C), glucose (Glu), insulin, leptin and adiponectin levels were measured. Gene regulations and protein levels were investigated using quantitative PCR and western blot in liver. RESULTS We found that the DHA/EPA diet protected against hepatic steatosis effectively in SKO mice morphologically. Hepatic TG content was decreased about 40 % (p < 0.05) in SKO mice fed with the DHA/EPA diet compared to chow fed SKO controls. Glucose and insulin tolerance were also improved significantly in SKO mice with DHA/EPA diet. In analyzing hepatic gene expression pattern it was found that TG synthesis related genes, such as carbohydrate response element binding protein (ChREBP), stearoyl-CoA desaturase 1 (SCD1) and fatty acid synthase (Fas) were upregulated in SKO mice compared to WT mice but were significantly decreased in SKO mice on DHA/EPA diet. Fatty acid β-oxidation related genes, on the other hand, such as peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase (CPT) and acyl-CoA oxidase 1 (ACOX1) were elevated in both WT and SKO groups on DHA/EPA diets. The protein levels of PPARα, SCD1, CPT1α, Insulin receptor substrate 1 (IRS1) and ratio of p-AKT to AKT showed the same tendency as the result of genes expressions. CONCLUSIONS The results suggest that n-3 PUFAs rich diet ameliorates lipodystrophy-induced hepatic steatosis through reducing TG synthesis, improving insulin resistance and enhancing β-oxidation in SKO mice.
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Affiliation(s)
- Pengfei Xu
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People's Republic of China
| | - Huan Wang
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People's Republic of China
| | - Abudurexiti Kayoumu
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People's Republic of China
| | - Mengyu Wang
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People's Republic of China
| | - Wei Huang
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People's Republic of China
| | - George Liu
- Institute of Cardiovascular Sciences, Key Laboratory of Molecular Cardiovascular Sciences, School of Basic Medical Sciences, Peking University Health Science Center, 38, XueYuan Road, HaiDian District, Beijing, 100191 People's Republic of China
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