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Abstract
Adipose tissue plays a central role in regulating whole-body energy and glucose homeostasis through its subtle functions at both organ and systemic levels. On one hand, adipose tissue stores energy in the form of lipid and controls the lipid mobilization and distribution in the body. On the other hand, adipose tissue acts as an endocrine organ and produces numerous bioactive factors such as adipokines that communicate with other organs and modulate a range of metabolic pathways. Moreover, brown and beige adipose tissue burn lipid by dissipating energy in the form of heat to maintain euthermia, and have been considered as a new way to counteract obesity. Therefore, adipose tissue dysfunction plays a prominent role in the development of obesity and its related disorders such as insulin resistance, cardiovascular disease, diabetes, depression and cancer. In this review, we will summarize the recent findings of adipose tissue in the control of metabolism, focusing on its endocrine and thermogenic function.
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Affiliation(s)
- Liping Luo
- Department of Metabolism and EndocrinologyMetabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital,
Central South University, Changsha, Hunan, China
| | - Meilian Liu
- Department of Metabolism and EndocrinologyMetabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital,
Central South University, Changsha, Hunan, China
- Department of Biochemistry and Molecular BiologyUniversity of New Mexico Health Sciences Center,
Albuquerque, New Mexico, USA
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52
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Loke SY, Wong PTH, Ong WY. Global gene expression changes in the prefrontal cortex of rabbits with hypercholesterolemia and/or hypertension. Neurochem Int 2016; 102:33-56. [PMID: 27890723 DOI: 10.1016/j.neuint.2016.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 11/14/2016] [Accepted: 11/23/2016] [Indexed: 02/01/2023]
Abstract
Although many studies have identified a link between hypercholesterolemia or hypertension and cognitive deficits, till date, comprehensive gene expression analyses of the brain under these conditions is still lacking. The present study was carried out to elucidate differential gene expression changes in the prefrontal cortex (PFC) of New Zealand white rabbits exposed to hypercholesterolemia and/or hypertension with a view of identifying gene networks at risk. Microarray analyses of the PFC of hypercholesterolemic rabbits showed 850 differentially expressed genes (DEGs) in the cortex of hypercholesterolemic rabbits compared to controls, but only 5 DEGs in hypertensive rabbits compared to controls. Up-regulated genes in the PFC of hypercholesterolemic rabbits included CIDEC, ODF2, RNASEL, FSHR, CES3 and MAB21L3, and down-regulated genes included FAM184B, CUL3, LOC100351029, TMEM109, LOC100357097 and PFDN5. Comparison with our previous study on the middle cerebral artery (MCA) of the same rabbits showed many differentially expressed genes in common between the PFC and MCA, during hypercholesterolemia. Moreover, these genes tended to fall into the same functional networks, as revealed by IPA analyses, with many identical node molecules. These include: proteasome, insulin, Akt, ERK1/2, histone, IL12, interferon alpha and NFκB. Of these, PSMB4, PSMD4, PSMG1 were chosen as representatives of genes related to the proteasome for verification by quantitative RT-PCR. Results indicate significant downregulation of all three proteasome associated genes in the PFC. Immunostaining showed significantly increased number of Aβ labelled cells in layers III and V of the cortex after hypercholesterolemia and hypertension, which may be due to decreased proteasome activity and/or increased β- or γ-secretase activity. Knowledge of altered gene networks during hypercholesterolemia and/or hypertension could inform our understanding of the link between these conditions and cognitive deficits in vascular dementia or Alzheimer's disease.
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Affiliation(s)
- Sau-Yeen Loke
- Department of Anatomy, National University of Singapore, 119260, Singapore
| | - Peter Tsun-Hon Wong
- Department of Pharmacology, National University of Singapore, 119260, Singapore
| | - Wei-Yi Ong
- Department of Anatomy, National University of Singapore, 119260, Singapore; Neurobiology and Ageing Research Program, Life Sciences Institute, National University of Singapore, 119260, Singapore.
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53
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DiStefano MT, Roth Flach RJ, Senol-Cosar O, Danai LV, Virbasius JV, Nicoloro SM, Straubhaar J, Dagdeviren S, Wabitsch M, Gupta OT, Kim JK, Czech MP. Adipocyte-specific Hypoxia-inducible gene 2 promotes fat deposition and diet-induced insulin resistance. Mol Metab 2016; 5:1149-1161. [PMID: 27900258 PMCID: PMC5123203 DOI: 10.1016/j.molmet.2016.09.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 09/15/2016] [Accepted: 09/19/2016] [Indexed: 12/18/2022] Open
Abstract
Objective Adipose tissue relies on lipid droplet (LD) proteins in its role as a lipid-storing endocrine organ that controls whole body metabolism. Hypoxia-inducible Gene 2 (Hig2) is a recently identified LD-associated protein in hepatocytes that promotes hepatic lipid storage, but its role in the adipocyte had not been investigated. Here we tested the hypothesis that Hig2 localization to LDs in adipocytes promotes adipose tissue lipid deposition and systemic glucose homeostasis. Method White and brown adipocyte-deficient (Hig2fl/fl × Adiponection cre+) and selective brown/beige adipocyte-deficient (Hig2fl/fl × Ucp1 cre+) mice were generated to investigate the role of Hig2 in adipose depots. Additionally, we used multiple housing temperatures to investigate the role of active brown/beige adipocytes in this process. Results Hig2 localized to LDs in SGBS cells, a human adipocyte cell strain. Mice with adipocyte-specific Hig2 deficiency in all adipose depots demonstrated reduced visceral adipose tissue weight and increased glucose tolerance. This metabolic effect could be attributed to brown/beige adipocyte-specific Hig2 deficiency since Hig2fl/fl × Ucp1 cre+ mice displayed the same phenotype. Furthermore, when adipocyte-deficient Hig2 mice were moved to thermoneutral conditions in which non-shivering thermogenesis is deactivated, these improvements were abrogated and glucose intolerance ensued. Adipocyte-specific Hig2 deficient animals displayed no detectable changes in adipocyte lipolysis or energy expenditure, suggesting that Hig2 may not mediate these metabolic effects by restraining lipolysis in adipocytes. Conclusions We conclude that Hig2 localizes to LDs in adipocytes, promoting adipose tissue lipid deposition and that its selective deficiency in active brown/beige adipose tissue mediates improved glucose tolerance at 23 °C. Reversal of this phenotype at thermoneutrality in the absence of detectable changes in energy expenditure, adipose mass, or liver triglyceride suggests that Hig2 deficiency triggers a deleterious endocrine or neuroendocrine pathway emanating from brown/beige fat cells. Hig2 localizes to lipid droplets in adipocytes and promotes adipose tissue lipid deposition. Its selective deficiency in active brown/beige adipose tissue mediates improved glucose tolerance at 23 °C. Metabolic improvements are independent of changes in lipolysis.
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Key Words
- Adipocyte
- BAT, brown adipose tissue
- FFA, free fatty acid
- GTT, glucose tolerance test
- HFD, high fat diet
- Hig2, Hypoxia-inducible gene 2
- Hypoxia-inducible gene 2 (Hig2)
- ITT, insulin tolerance test
- LD, lipid droplet
- Lipid droplet
- Lipolysis
- NEFA, non-esterified fatty acid
- Obesity
- RER, respiratory exchange ratio
- SGBS, Simpson-Golabi-Behmel syndrome
- SVF, stromal vascular fraction
- TG, triglyceride
- Ucp1, uncoupling protein 1
- WAT, white adipose tissue
- eWAT, epididymal white adipose tissue
- iWAT, inguinal white adipose tissue
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Affiliation(s)
- Marina T DiStefano
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rachel J Roth Flach
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ozlem Senol-Cosar
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Laura V Danai
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Joseph V Virbasius
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sarah M Nicoloro
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Juerg Straubhaar
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sezin Dagdeviren
- From the Program in Molecular Medicine and the Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Martin Wabitsch
- From the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm 89075, Germany
| | - Olga T Gupta
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jason K Kim
- From the Program in Molecular Medicine and the Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Michael P Czech
- From the Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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54
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Li Y, Li A, Yang ZQ. Molecular cloning, genomic organization, chromosome mapping, tissues expression pattern and identification of a novel splicing variant of porcine CIDEb gene. Biochem Biophys Res Commun 2016; 478:486-493. [PMID: 27207838 DOI: 10.1016/j.bbrc.2016.05.079] [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: 05/05/2016] [Accepted: 05/15/2016] [Indexed: 11/18/2022]
Abstract
Cell death-inducing DNA fragmentation factor-α-like effector b (CIDEb) is a member of the CIDE family of apoptosis-inducing factors, CIDEa and CIDEc have been reported to be Lipid droplets (LDs)-associated proteins that promote atypical LD fusion in adipocytes, and responsible for liver steatosis under fasting and obese conditions, whereas CIDEb promotes lipid storage under normal diet conditions [1], and promotes the formation of triacylglyceride-enriched VLDL particles in hepatocytes [2]. Here, we report the gene cloning, chromosome mapping, tissue distribution, genetic expression analysis, and identification of a novel splicing variant of the porcine CIDEb gene. Sequence analysis shows that the open reading frame of the normal porcine CIDEb isoform covers 660bp and encodes a 219-amino acid polypeptide, whereas its alternative splicing variant encodes a 142-amino acid polypeptide truncated at the fourth exon and comprised of the CIDE-N domain and part of the CIDE-C domain. The deduced amino acid sequence of normal porcine CIDEb shows an 85.8% similarity to the human protein and 80.0% to the mouse protein. The CIDEb genomic sequence spans approximately 6KB comprised of five exons and four introns. Radiation hybrid mapping demonstrated that porcine CIDEb is located at chromosome 7q21 and at a distance of 57cR from the most significantly linked marker, S0334, regions that are syntenic with the corresponding region in the human genome. Tissue expression analysis indicated that normal CIDEb mRNA is ubiquitously expressed in many porcine tissues. It was highly expressed in white adipose tissue and was observed at relatively high levels in the liver, lung, small intestine, lymphatic tissue and brain. The normal version of CIDEb was the predominant form in all tested tissues, whereas the splicing variant was expressed at low levels in all examined tissues except the lymphatic tissue. Furthermore, genetic expression analysis indicated that CIDEb mRNA levels were significantly higher in the white adipose tissue of lean pigs than their obese counterparts, in contrast to porcine CIDEa and CIDEc [3]. We therefore speculate that CIDEb may play a contrary role to the other CIDEs. The basic molecular information we provide here will be useful for further investigations of the physiological function of the gene, which will be helpful in better understanding the role of the CIDE family in lipid metabolism in pig models.
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Affiliation(s)
- YanHua Li
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing 400014, PR China.
| | - AiHua Li
- Chongqing Cancer Institute & Hospital & Cancer Center, Chongqing 404100, PR China
| | - Z Q Yang
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
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55
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Akil A, Peng J, Omrane M, Gondeau C, Desterke C, Marin M, Tronchère H, Taveneau C, Sar S, Briolotti P, Benjelloun S, Benjouad A, Maurel P, Thiers V, Bressanelli S, Samuel D, Bréchot C, Gassama-Diagne A. Septin 9 induces lipid droplets growth by a phosphatidylinositol-5-phosphate and microtubule-dependent mechanism hijacked by HCV. Nat Commun 2016; 7:12203. [PMID: 27417143 PMCID: PMC4947189 DOI: 10.1038/ncomms12203] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 06/07/2016] [Indexed: 01/09/2023] Open
Abstract
The accumulation of lipid droplets (LD) is frequently observed in hepatitis C virus (HCV) infection and represents an important risk factor for the development of liver steatosis and cirrhosis. The mechanisms of LD biogenesis and growth remain open questions. Here, transcriptome analysis reveals a significant upregulation of septin 9 in HCV-induced cirrhosis compared with the normal liver. HCV infection increases septin 9 expression and induces its assembly into filaments. Septin 9 regulates LD growth and perinuclear accumulation in a manner dependent on dynamic microtubules. The effects of septin 9 on LDs are also dependent on binding to PtdIns5P, which, in turn, controls the formation of septin 9 filaments and its interaction with microtubules. This previously undescribed cooperation between PtdIns5P and septin 9 regulates oleate-induced accumulation of LDs. Overall, our data offer a novel route for LD growth through the involvement of a septin 9/PtdIns5P signalling pathway.
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Affiliation(s)
- Abdellah Akil
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France.,Laboratoire des Hépatites Virales, Département de Virologie. Institut Pasteur du Maroc, BP 20360 Casablanca, Maroc.,Faculté des Sciences, Laboratoire de Biochimie-Immunologie, Univ. Mohammed V, Rabat, Maroc
| | - Juan Peng
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France.,DHU Hepatinov, Villejuif F-94800, France
| | - Mohyeddine Omrane
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France.,DHU Hepatinov, Villejuif F-94800, France
| | - Claire Gondeau
- INSERM U1183, Institute of Regenerative Medicine and Biotherapy, University of Montpellier, 34295 Montpellier, France.,Department of Hepato-Gastroenterology A, Hospital Saint Eloi, CHRU, 34295 Montpellier, France
| | | | - Mickaël Marin
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France
| | - Hélène Tronchère
- INSERM U1048, I2MC and Université Paul Sabatier, 31432 Toulouse, France
| | - Cyntia Taveneau
- Virologie Moléculaire et Structurale CNRS UPR 3296 - INRA UsC 1358, 91198 Gif-sur-Yvette, France
| | - Sokhavuth Sar
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France
| | - Philippe Briolotti
- INSERM U1183, Institute of Regenerative Medicine and Biotherapy, University of Montpellier, 34295 Montpellier, France.,Department of Hepato-Gastroenterology A, Hospital Saint Eloi, CHRU, 34295 Montpellier, France
| | - Soumaya Benjelloun
- Laboratoire des Hépatites Virales, Département de Virologie. Institut Pasteur du Maroc, BP 20360 Casablanca, Maroc
| | - Abdelaziz Benjouad
- Faculté des Sciences, Laboratoire de Biochimie-Immunologie, Univ. Mohammed V, Rabat, Maroc.,Univ. Internationale de Rabat, Sala Al Jadida, Maroc
| | - Patrick Maurel
- INSERM U1183, Institute of Regenerative Medicine and Biotherapy, University of Montpellier, 34295 Montpellier, France.,Department of Hepato-Gastroenterology A, Hospital Saint Eloi, CHRU, 34295 Montpellier, France
| | | | - Stéphane Bressanelli
- Virologie Moléculaire et Structurale CNRS UPR 3296 - INRA UsC 1358, 91198 Gif-sur-Yvette, France
| | - Didier Samuel
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France.,DHU Hepatinov, Villejuif F-94800, France.,AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif F-94800, France
| | - Christian Bréchot
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France.,Institut Pasteur, 75724 Paris, France
| | - Ama Gassama-Diagne
- INSERM, Unité 1193, F-94800 Villejuif, France.,University of Paris-Sud, UMR-S 1193, F-94800 Villejuif, France.,DHU Hepatinov, Villejuif F-94800, France
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56
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Liangpunsakul S, Gao B. Alcohol and fat promote steatohepatitis: a critical role for fat-specific protein 27/CIDEC. J Investig Med 2016; 64:1078-81. [PMID: 27342423 DOI: 10.1136/jim-2016-000204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2016] [Indexed: 12/20/2022]
Abstract
Alcoholic liver disease (ALD) is a major public health problem worldwide and is the leading cause of end-stage liver disease. While the ultimate control of ALD will require the prevention of alcohol abuse, better understanding of the mechanisms of alcohol-induced liver injury may lead to treatments of fatty liver, alcoholic hepatitis, and prevention or delay of occurrence of cirrhosis. The elucidation and the discovery of several new concepts in ALD pathogenesis have raised our understanding on the complex mechanisms and the potential in developing the new strategies for therapeutic benefits. In this review, we provide the most up-to-date information on the basic molecular mechanisms focusing on the role of fat-specific protein 27/CIDEC in the pathogenesis of ALD.
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Affiliation(s)
- Suthat Liangpunsakul
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA Indiana University School of Medicine, Indianapolis, Indiana, USA Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA
| | - Bin Gao
- Laboratory of Liver Diseases, National Institute of Alcohol Abuse and Alcoholism, Rockville, Maryland, USA
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57
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Lipid droplet-associated proteins in atherosclerosis (Review). Mol Med Rep 2016; 13:4527-34. [PMID: 27082419 PMCID: PMC4878557 DOI: 10.3892/mmr.2016.5099] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 01/29/2016] [Indexed: 01/01/2023] Open
Abstract
Accumulation of atherosclerotic plaques in arterial walls leads to major cardiovascular diseases and stroke. Macrophages/foam cells are central components of atherosclerotic plaques, which populate the arterial wall in order to remove harmful modified low‑density lipoprotein (LDL) particles, resulting in the accumulation of lipids, mostly LDL‑derived cholesterol ester, in cytosolic lipid droplets (LDs). At present, LDs are recognized as dynamic organelles that govern cellular metabolic processes. LDs consist of an inner core of neutral lipids surrounded by a monolayer of phospholipids and free cholesterol, and contain LD‑associated proteins (LDAPs) that regulate LD functions. Foam cells are characterized by an aberrant accumulation of cytosolic LDs, and are considered a hallmark of atherosclerotic lesions through all stages of development. Previous studies have investigated the mechanisms underlying foam cell formation, aiming to discover therapeutic strategies that target foam cells and intervene against atherosclerosis. It is well established that LDAPs have a major role in the pathogenesis of metabolic diseases caused by dysfunction of lipid metabolism, and several studies have linked LDAPs to the development of atherosclerosis. In this review, several foam cell‑targeting pathways have been described, with an emphasis on the role of LDAPs in cholesterol mobilization from macrophages. In addition, the potential of LDAPs as therapeutic targets to prevent the progression and/or facilitate the regression of the disease has been discussed.
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58
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Calderon-Dominguez M, Mir JF, Fucho R, Weber M, Serra D, Herrero L. Fatty acid metabolism and the basis of brown adipose tissue function. Adipocyte 2016; 5:98-118. [PMID: 27386151 PMCID: PMC4916887 DOI: 10.1080/21623945.2015.1122857] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/13/2015] [Accepted: 11/12/2015] [Indexed: 12/21/2022] Open
Abstract
Obesity has reached epidemic proportions, leading to severe associated pathologies such as insulin resistance, cardiovascular disease, cancer and type 2 diabetes. Adipose tissue has become crucial due to its involvement in the pathogenesis of obesity-induced insulin resistance, and traditionally white adipose tissue has captured the most attention. However in the last decade the presence and activity of heat-generating brown adipose tissue (BAT) in adult humans has been rediscovered. BAT decreases with age and in obese and diabetic patients. It has thus attracted strong scientific interest, and any strategy to increase its mass or activity might lead to new therapeutic approaches to obesity and associated metabolic diseases. In this review we highlight the mechanisms of fatty acid uptake, trafficking and oxidation in brown fat thermogenesis. We focus on BAT's morphological and functional characteristics and fatty acid synthesis, storage, oxidation and use as a source of energy.
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Affiliation(s)
- María Calderon-Dominguez
- Department of Biochemistry and Molecular Biology, School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Joan F. Mir
- Department of Biochemistry and Molecular Biology, School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Raquel Fucho
- Department of Biochemistry and Molecular Biology, School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Minéia Weber
- Department of Biochemistry and Molecular Biology, School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Dolors Serra
- Department of Biochemistry and Molecular Biology, School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Laura Herrero
- Department of Biochemistry and Molecular Biology, School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
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Lu S, Bennett RG, Kharbanda KK, Harrison-Findik DD. Lack of hepcidin expression attenuates steatosis and causes fibrosis in the liver. World J Hepatol 2016; 8:211-225. [PMID: 26855692 PMCID: PMC4733464 DOI: 10.4254/wjh.v8.i4.211] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 10/14/2015] [Accepted: 11/13/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the role of key iron-regulatory protein, hepcidin in non-alcoholic fatty liver disease (NAFLD).
METHODS: Hepcidin (Hamp1) knockout and floxed control mice were administered a high fat and high sucrose (HFS) or a regular control diet for 3 or 7 mo. Steatosis, triglycerides, fibrosis, protein and gene expression in mice livers were determined by histological and biochemical techniques, western blotting and real-time polymerase chain reaction.
RESULTS: Knockout mice exhibited hepatic iron accumulation. Despite similar weight gains, HFS feeding induced hepatomegaly in floxed, but not knockout, mice. The livers of floxed mice exhibited higher levels of steatosis, triglycerides and c-Jun N-terminal kinase (JNK) phosphorylation than knockout mice. In contrast, a significant increase in fibrosis was observed in knockout mice livers within 3 mo of HFS administration. The hepatic gene expression levels of sterol regulatory element-binding protein-1c and fat-specific protein-27, but not peroxisome proliferator-activated receptor-alpha or microsomal triglyceride transfer protein, were attenuated in HFS-fed knockout mice. Knockout mice fed with regular diet displayed increased carnitine palmitoyltransferase-1a and phosphoenolpyruvate carboxykinase-1 but decreased glucose-6-phosphatase expression in the liver. In summary, attenuated steatosis correlated with decreased expression of lipogenic and lipid storage genes, and JNK phosphorylation. Deletion of Hamp1 alleles per se modulated hepatic expression of beta-oxidation and gluconeogenic genes.
CONCLUSION: Lack of hepcidin expression inhibits hepatic lipid accumulation and induces early development of fibrosis following high fat intake. Hepcidin and iron may play a role in the regulation of metabolic pathways in the liver, which has implications for NAFLD pathogenesis.
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60
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Xu W, Wu L, Yu M, Chen FJ, Arshad M, Xia X, Ren H, Yu J, Xu L, Xu D, Li JZ, Li P, Zhou L. Differential Roles of Cell Death-inducing DNA Fragmentation Factor-α-like Effector (CIDE) Proteins in Promoting Lipid Droplet Fusion and Growth in Subpopulations of Hepatocytes. J Biol Chem 2016; 291:4282-93. [PMID: 26733203 DOI: 10.1074/jbc.m115.701094] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Indexed: 01/21/2023] Open
Abstract
Lipid droplets (LDs) are dynamic subcellular organelles whose growth is closely linked to obesity and hepatic steatosis. Cell death-inducing DNA fragmentation factor-α-like effector (CIDE) proteins, including Cidea, Cideb, and Cidec (also called Fsp27), play important roles in lipid metabolism. Cidea and Cidec are LD-associated proteins that promote atypical LD fusion in adipocytes. Here, we find that CIDE proteins are all localized to LD-LD contact sites (LDCSs) and promote lipid transfer, LD fusion, and growth in hepatocytes. We have identified two types of hepatocytes, one with small LDs (small LD-containing hepatocytes, SLHs) and one with large LDs (large LD-containing hepatocytes, LLHs) in the liver. Cideb is localized to LDCSs and promotes lipid exchange and LD fusion in both SLHs and LLHs, whereas Cidea and Cidec are specifically localized to the LDCSs and promote lipid exchange and LD fusion in LLHs. Cideb-deficient SLHs have reduced LD sizes and lower lipid exchange activities. Fasting dramatically induces the expression of Cidea/Cidec and increases the percentage of LLHs in the liver. The majority of the hepatocytes from the liver of obese mice are Cidea/Cidec-positive LLHs. Knocking down Cidea or Cidec significantly reduced lipid storage in the livers of obese animals. Our data reveal that CIDE proteins play differential roles in promoting LD fusion and lipid storage; Cideb promotes lipid storage under normal diet conditions, whereas Cidea and Cidec are responsible for liver steatosis under fasting and obese conditions.
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Affiliation(s)
- Wenyi Xu
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lizhen Wu
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Miao Yu
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Feng-Jung Chen
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Muhammad Arshad
- the Department of Bioinformatics and Biotechnology, International Islamic University, Islamabad 44000, Pakistan
| | - Xiayu Xia
- the Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences, Beijing 100021, China
| | - Hao Ren
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jinhai Yu
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Li Xu
- the Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China, and
| | - Dijin Xu
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - John Zhong Li
- the Jiangsu Province Key Laboratory of Human Functional Genomics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 210029, China
| | - Peng Li
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China,
| | - Linkang Zhou
- From the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China,
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Schneider MR. Lipid droplets and associated proteins in sebocytes. Exp Cell Res 2016; 340:205-8. [DOI: 10.1016/j.yexcr.2015.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 11/06/2015] [Accepted: 11/08/2015] [Indexed: 12/19/2022]
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Zhu YX, Zhang ML, Zhong Y, Wang C, Jia WP. Modulation Effect of Peroxisome Proliferator-Activated Receptor Agonists on Lipid Droplet Proteins in Liver. J Diabetes Res 2016; 2016:8315454. [PMID: 26770990 PMCID: PMC4684860 DOI: 10.1155/2016/8315454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 06/02/2015] [Accepted: 07/01/2015] [Indexed: 12/14/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR) agonists are used for treating hyperglycemia and type 2 diabetes. However, the mechanism of action of these agonists is still under investigation. The lipid droplet-associated proteins FSP27/CIDEC and LSDP5, regulated directly by PPARγ and PPARα, are associated with hepatic steatosis and insulin sensitivity. Here, we evaluated the expression levels of FSP27/CIDEC and LSDP5 and the regulation of these proteins by consumption of a high-fat diet (HFD) or administration of PPAR agonists. Mice with diet-induced obesity were treated with the PPARγ or PPARα agonist, pioglitazone or fenofibrate, respectively. Liver tissues from db/db diabetic mice and human were also collected. Interestingly, FSP27/CIEDC was expressed in mouse and human livers and was upregulated in obese C57BL/6J mice. Fenofibrate treatment decreased hepatic triglyceride (TG) content and FSP27/CIDEC protein expression in mice fed an HFD diet. In mice, LSDP5 was not detected, even in the context of insulin resistance or treatment with PPAR agonists. However, LSDP5 was highly expressed in humans, with elevated expression observed in the fatty liver. We concluded that fenofibrate greatly decreased hepatic TG content and FSP27/CIDEC protein expression in mice fed an HFD, suggesting a potential regulatory role for fenofibrate in the amelioration of hepatic steatosis.
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Affiliation(s)
- Yun-Xia Zhu
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Ming-Liang Zhang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Yuan Zhong
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Chen Wang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
- Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai 200233, China
- Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
- *Chen Wang:
| | - Wei-Ping Jia
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
- Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai 200233, China
- Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
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Lipid droplets and associated proteins in the skin: basic research and clinical perspectives. Arch Dermatol Res 2015; 308:1-6. [PMID: 26437897 DOI: 10.1007/s00403-015-1599-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/19/2015] [Accepted: 09/21/2015] [Indexed: 10/23/2022]
Abstract
Lipid droplets (LDs), the major organelles handling fat storage, comprise a hydrophobic neutral lipid core surrounded by a phospholipid monolayer embedded with a protein miscellany. Although lipids of the stratum corneum are essential for the skin barrier, and progressive lipid accumulation culminating in cell disruption is the hallmark of sebaceous differentiation, only a few studies touched on skin LD and associated proteins so far. Here, after briefly introducing the basic facts about LD and associated proteins, we discuss how forthcoming studies may unveil novel players in skin lipid metabolism and candidate target proteins for treating skin diseases.
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Xu MJ, Cai Y, Wang H, Altamirano J, Chang B, Bertola A, Odena G, Lu J, Tanaka N, Matsusue K, Matsubara T, Mukhopadhyay P, Kimura S, Pacher P, Gonzalez FJ, Bataller R, Gao B. Fat-Specific Protein 27/CIDEC Promotes Development of Alcoholic Steatohepatitis in Mice and Humans. Gastroenterology 2015; 149:1030-41.e6. [PMID: 26099526 PMCID: PMC4584194 DOI: 10.1053/j.gastro.2015.06.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 05/29/2015] [Accepted: 06/09/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Alcoholic steatohepatitis (ASH) is the progressive form of alcoholic liver disease and may lead to cirrhosis and hepatocellular carcinoma. We studied mouse models and human tissues to identify molecules associated with ASH progression and focused on the mouse fat-specific protein 27 (FSP-27)/human cell death-inducing DFF45-like effector C (CIDEC) protein, which is expressed in white adipose tissues and promotes formation of fat droplets. METHODS C57BL/6N mice or mice with hepatocyte-specific disruption of Fsp27 (Fsp27(Hep-/-) mice) were fed the Lieber-Decarli ethanol liquid diet (5% ethanol) for 10 days to 12 weeks, followed by 1 or multiple binges of ethanol (5 or 6 g/kg) during the chronic feeding. Some mice were given an inhibitor (GW9662) of peroxisome proliferator-activated receptor γ (PPARG). Adenoviral vectors were used to express transgenes or small hairpin (sh) RNAs in cultured hepatocytes and in mice. Liver tissue samples were collected from ethanol-fed mice or from 31 patients with alcoholic hepatitis (AH) with biopsy-proved ASH and analyzed histologically and immunohistochemically and by transcriptome, immunoblotting, and real-time PCR analyses. RESULTS Chronic-plus-binge ethanol feeding of mice, which mimics the drinking pattern of patients with AH, produced severe ASH and mild fibrosis. Microarray analyses revealed similar alterations in expression of many hepatic genes in ethanol-fed mice and humans with ASH, including up-regulation of mouse Fsp27 (also called Cidec) and human CIDEC. Fsp27(Hep-/-) mice and mice given injections of adenovirus-Fsp27shRNA had markedly reduced ASH following chronic-plus-binge ethanol feeding. Inhibition of PPARG and cyclic AMP-responsive element binding protein H (CREBH) prevented the increases in Fsp27α and FSP27β mRNAs, respectively, and reduced liver injury in this chronic-plus-binge ethanol feeding model. Overexpression of FSP27 and ethanol exposure had synergistic effects in inducing production of mitochondrial reactive oxygen species and damage to hepatocytes in mice. Hepatic CIDEC mRNA expression was increased in patients with AH and correlated with the degree of hepatic steatosis and disease severity including mortality. CONCLUSIONS In mice, chronic-plus-binge ethanol feeding induces ASH that mimics some histological and molecular features observed in patients with AH. Hepatic expression of FSP27/CIDEC is highly up-regulated in mice following chronic-plus-binge ethanol feeding and in patients with AH; this up-regulation contributes to alcohol-induced liver damage.
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Affiliation(s)
- Ming-Jiang Xu
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Department of Physiology and Pathophysiology, School of Basic Medical Science, Peking University, Beijing, China
| | - Yan Cai
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Hua Wang
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - José Altamirano
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Liver Unit-Internal Medicine Department, Vall d'Hebron Hospital, Vall d'Hebron Institut de Recerca, Barcelona, Spain
| | - Binxia Chang
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Adeline Bertola
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Gemma Odena
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jim Lu
- GoPath Diagnostics, LLC, Chicago, Illinois
| | - Naoki Tanaka
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Kimihiko Matsusue
- Faculty of Pharmaceutical Science, Fukuoka University, Fukuoka, Japan
| | - Tsutomu Matsubara
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Partha Mukhopadhyay
- Section of Oxidative Stress and Tissue Injury, Laboratory of Physiological Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Shioko Kimura
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Pal Pacher
- Section of Oxidative Stress and Tissue Injury, Laboratory of Physiological Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Ramon Bataller
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Liver Unit-Internal Medicine Department, Vall d'Hebron Hospital, Vall d'Hebron Institut de Recerca, Barcelona, Spain; Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, North Carolina
| | - Bin Gao
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland.
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Xu Y, Gu Y, Liu G, Zhang F, Li J, Liu F, Zhang Z, Ye J, Li Q. Cidec promotes the differentiation of human adipocytes by degradation of AMPKα through ubiquitin-proteasome pathway. Biochim Biophys Acta Gen Subj 2015; 1850:2552-62. [PMID: 26367078 DOI: 10.1016/j.bbagen.2015.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 08/30/2015] [Accepted: 09/10/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND We previously showed that Cidec was localized on the surface of lipid droplets and could promote the differentiation of human adipocytes, but the molecular mechanism was still unknown. METHODS & RESULTS In this study, we first sought to identify proteins that interact with Cidec using yeast two-hybrid system. The results revealed that Cidec could directly interact with AMPKα1 subunit. We further showed that AMPKα levels decreased while Cidec increased during the adipogenic differentiation of human adipocytes. Meanwhile, we observed that the increased Cidec could reduce AMPKα level in adipocytes, and the downregulation of AMPKα could help to promote the differentiation of adipocytes. The results of co-immunoprecipitation and immunofluorescent proved that Cidec biochemically interacted and co-localized with AMPKα1, which meant Cidec was a regulator for AMPKα stability through an ubiquitin-proteasome pathway. CONCLUSION Our data suggested that Cidec could interact with and down-regulate AMPKα through an ubiquitin-proteasome degradation pathway, which provided a possible mechanism of Cidec in promoting human adipocytes differentiation. GENERAL SIGNIFICANCE Our work proposed a new possible mechanism for human adipogenesis, and also provided a potential role of AMPKα as a target in treating obesity or obesity-related diseases.
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Affiliation(s)
- Yuqiao Xu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Yu Gu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Gang Liu
- Department of Plastic and Burns, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Feng Zhang
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Jie Li
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Fang Liu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Zhiwen Zhang
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Jing Ye
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China.
| | - Qing Li
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China.
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Deol P, Evans JR, Dhahbi J, Chellappa K, Han DS, Spindler S, Sladek FM. Soybean Oil Is More Obesogenic and Diabetogenic than Coconut Oil and Fructose in Mouse: Potential Role for the Liver. PLoS One 2015. [PMID: 26200659 PMCID: PMC4511588 DOI: 10.1371/journal.pone.0132672] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The obesity epidemic in the U.S. has led to extensive research into potential contributing dietary factors, especially fat and fructose. Recently, increased consumption of soybean oil, which is rich in polyunsaturated fatty acids (PUFAs), has been proposed to play a causal role in the epidemic. Here, we designed a series of four isocaloric diets (HFD, SO-HFD, F-HFD, F-SO-HFD) to investigate the effects of saturated versus unsaturated fat, as well as fructose, on obesity and diabetes. C57/BL6 male mice fed a diet moderately high in fat from coconut oil and soybean oil (SO-HFD, 40% kcal total fat) showed statistically significant increases in weight gain, adiposity, diabetes, glucose intolerance and insulin resistance compared to mice on a diet consisting primarily of coconut oil (HFD). They also had fatty livers with hepatocyte ballooning and very large lipid droplets as well as shorter colonic crypt length. While the high fructose diet (F-HFD) did not cause as much obesity or diabetes as SO-HFD, it did cause rectal prolapse and a very fatty liver, but no balloon injury. The coconut oil diet (with or without fructose) increased spleen weight while fructose in the presence of soybean oil increased kidney weight. Metabolomics analysis of the liver showed an increased accumulation of PUFAs and their metabolites as well as γ-tocopherol, but a decrease in cholesterol in SO-HFD. Liver transcriptomics analysis revealed a global dysregulation of cytochrome P450 (Cyp) genes in SO-HFD versus HFD livers, most notably in the Cyp3a and Cyp2c families. Other genes involved in obesity (e.g., Cidec, Cd36), diabetes (Igfbp1), inflammation (Cd63), mitochondrial function (Pdk4) and cancer (H19) were also upregulated by the soybean oil diet. Taken together, our results indicate that in mice a diet high in soybean oil is more detrimental to metabolic health than a diet high in fructose or coconut oil.
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Affiliation(s)
- Poonamjot Deol
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California, United States of America
| | - Jane R. Evans
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California, United States of America
| | - Joseph Dhahbi
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Karthikeyani Chellappa
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California, United States of America
| | - Diana S. Han
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California, United States of America
| | - Stephen Spindler
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Frances M. Sladek
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, California, United States of America
- * E-mail:
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Labrie M, Lalonde S, Najyb O, Thiery M, Daneault C, Des Rosiers C, Rassart E, Mounier C. Apolipoprotein D Transgenic Mice Develop Hepatic Steatosis through Activation of PPARγ and Fatty Acid Uptake. PLoS One 2015; 10:e0130230. [PMID: 26083030 PMCID: PMC4470830 DOI: 10.1371/journal.pone.0130230] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 05/18/2015] [Indexed: 12/27/2022] Open
Abstract
Transgenic mice (Tg) overexpressing human apolipoprotein D (H-apoD) in the brain are resistant to neurodegeneration. Despite the use of a neuron-specific promoter to generate the Tg mice, they expressed significant levels of H-apoD in both plasma and liver and they slowly develop hepatic steatosis and insulin resistance. We show here that hepatic PPARγ expression in Tg mice is increased by 2-fold compared to wild type (WT) mice. Consequently, PPARγ target genes Plin2 and Cide A/C are overexpressed, leading to increased lipid droplets formation. Expression of the fatty acid transporter CD36, another PPARgamma target, is also increased in Tg mice associated with elevated fatty acid uptake as measured in primary hepatocytes. Elevated expression of AMPK in the liver of Tg leads to phosphorylation of acetyl CoA carboxylase, indicating a decreased activity of the enzyme. Fatty acid synthase expression is also induced but the hepatic lipogenesis measured in vivo is not significantly different between WT and Tg mice. In addition, expression of carnitine palmitoyl transferase 1, the rate-limiting enzyme of beta-oxidation, is slightly upregulated. Finally, we show that overexpressing H-apoD in HepG2 cells in presence of arachidonic acid (AA), the main apoD ligand, increases the transcriptional activity of PPARγ. Supporting the role of apoD in AA transport, we observed enrichment in hepatic AA and a decrease in plasmatic AA concentration. Taken together, our results demonstrate that the hepatic steatosis observed in apoD Tg mice is a consequence of increased PPARγ transcriptional activity by AA leading to increased fatty acid uptake by the liver.
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Affiliation(s)
- Marilyne Labrie
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Simon Lalonde
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Ouafa Najyb
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Maxime Thiery
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Caroline Daneault
- Montreal Heart Institute Research Center, Montreal, Quebec, H1T 1C8,Canada
| | - Chrisitne Des Rosiers
- Department of Nutrition, Université de Montréal, Montréal, Québec, H3C 3J7,Canada
- Montreal Heart Institute Research Center, Montreal, Quebec, H1T 1C8,Canada
| | - Eric Rassart
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Catherine Mounier
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
- * E-mail:
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Xu X, Park JG, So JS, Lee AH. Transcriptional activation of Fsp27 by the liver-enriched transcription factor CREBH promotes lipid droplet growth and hepatic steatosis. Hepatology 2015; 61:857-69. [PMID: 25125366 PMCID: PMC4329115 DOI: 10.1002/hep.27371] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/10/2014] [Indexed: 12/22/2022]
Abstract
UNLABELLED Fat-specific protein 27 (Fsp27) is a lipid droplet-associated protein that promotes lipid droplet (LD) growth and triglyceride (TG) storage in white adipocytes. Fsp27 is also highly expressed in the steatotic liver and contributes to TG accumulation. In this study we discovered that the liver produces Fsp27β, an alternative Fsp27 isoform, which contains 10 additional amino acids at the N-terminus of the original Fsp27 (Fsp27α). White adipose tissue (WAT) and the liver specifically expressed Fsp27α and Fsp27β transcripts, respectively, which were driven by distinct promoters. The Fsp27β promoter was activated by the liver-enriched transcription factor cyclic-AMP-responsive-element-binding protein H (CREBH) but not by peroxisome proliferator-activated receptor gamma (PPARγ), which activated the Fsp27α promoter. Enforced expression of the constitutively active CREBH strongly induced Fsp27β and the human ortholog CIDEC2 in mouse hepatocytes and HepG2 cells, respectively. In contrast, loss of CREBH decreased hepatic Fsp27β in fasted mice, suggesting that CREBH plays a critical role in Fsp27β expression in the liver. Similar to Fsp27α, Fsp27β localized on the surface of lipid droplets and suppressed lipolysis. Consequently, enforced expression of Fsp27β or CREBH promoted lipid droplet enlargement and TG accumulation in the liver. CONCLUSION The CREBH-Fsp27β axis is important for regulating lipid droplet dynamics and TG storage in the liver.
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Affiliation(s)
| | | | | | - Ann-Hwee Lee
- To whom correspondence should be addressed: Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA. Tel: 1-212-746-9087
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69
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Insulin resistance and white adipose tissue inflammation are uncoupled in energetically challenged Fsp27-deficient mice. Nat Commun 2015; 6:5949. [PMID: 25565658 PMCID: PMC4354252 DOI: 10.1038/ncomms6949] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 11/18/2014] [Indexed: 12/19/2022] Open
Abstract
Fsp27 is a lipid droplet-associated protein almost exclusively expressed in adipocytes where it facilitates unilocular lipid droplet formation. In mice, Fsp27 deficiency is associated with increased basal lipolysis, ‘browning’ of white fat and a healthy metabolic profile, whereas a patient with congenital CIDEC deficiency manifested an adverse lipodystrophic phenotype. Here we reconcile these data by showing that exposing Fsp27-null mice to a substantial energetic stress by crossing them with ob/ob mice or BATless mice, or feeding them a high-fat diet, results in hepatic steatosis and insulin resistance. We also observe a striking reduction in adipose inflammation and increase in adiponectin levels in all three models. This appears to reflect reduced activation of the inflammasome and less adipocyte death. These findings highlight the importance of Fsp27 in facilitating optimal energy storage in adipocytes and represent a rare example where adipose inflammation and hepatic insulin resistance are disassociated. Fsp27 mediates ‘fusion’ of lipid droplets in mouse adipose tissue. Here, the authors investigate the physiological consequences of loss of Fsp27 in three different mouse models of ‘energetic overload’, and observe hepatic steatosis and insulin resistance but reduced adipose tissue inflammation.
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70
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Wu L, Xu D, Zhou L, Xie B, Yu L, Yang H, Huang L, Ye J, Deng H, Yuan YA, Chen S, Li P. Rab8a-AS160-MSS4 regulatory circuit controls lipid droplet fusion and growth. Dev Cell 2014; 30:378-93. [PMID: 25158853 DOI: 10.1016/j.devcel.2014.07.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/06/2014] [Accepted: 07/10/2014] [Indexed: 11/15/2022]
Abstract
Rab GTPases, by targeting to specific membrane compartments, play essential roles in membrane trafficking. Lipid droplets (LDs) are dynamic subcellular organelles whose growth is closely linked to obesity and hepatic steatosis. Fsp27 is shown to be required for LD fusion and growth by enriching at LD-LD contact sites. Here, we identify Rab8a as a direct interactor and regulator of Fsp27 in mediating LD fusion in adipocytes. Knockdown of Rab8a in the livers of ob/ob mice results in the accumulation of smaller LDs and lower hepatic lipid levels. Surprisingly, it is the GDP-bound form of Rab8a that exhibits fusion-promoting activity. We further discover AS160 as the GTPase activating protein (GAP) for Rab8a, which forms a ternary complex with Fsp27 and Rab8a to positively regulate LD fusion. MSS4 antagonizes Fsp27-mediated LD fusion activity through Rab8a. Our results have thus revealed a mechanistic signaling circuit controlling LD fusion and fatty liver formation.
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Affiliation(s)
- Lizhen Wu
- MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Dijin Xu
- MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Linkang Zhou
- MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bingxian Xie
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - Li Yu
- MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW 2052, Australia
| | - Lei Huang
- Cell Biology Core Facility and Proteomics Facility, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jing Ye
- Department of Pathology, The Fourth Military Medical University, Xi'an 710032, China
| | - Haiteng Deng
- Cell Biology Core Facility and Proteomics Facility, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Y Adam Yuan
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Shuai Chen
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - Peng Li
- MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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Abstract
Accumulation of triacylglycerols within the cytoplasm of hepatocytes to the degree that lipid droplets are visible microscopically is called liver steatosis. Most commonly, it occurs when there is an imbalance between the delivery or synthesis of fatty acids in the liver and their disposal through oxidative pathways or secretion into the blood as a component of triacylglycerols in very low density lipoprotein. This disorder is called nonalcoholic fatty liver disease (NAFLD) in the absence of alcoholic abuse and viral hepatitis, and it is often associated with insulin resistance, obesity and type 2 diabetes. Also, liver steatosis can be induced by many other causes including excessive alcohol consumption, infection with genotype 3 hepatitis C virus and certain medications. Whereas hepatic triacylglycerol accumulation was once considered the ultimate effector of hepatic lipotoxicity, triacylglycerols per se are quite inert and do not induce insulin resistance or cellular injury. Rather, lipotoxic injury in the liver appears to be mediated by the global ongoing fatty acid enrichment in the liver, paralleling the development of insulin resistance. A considerable number of fatty acid metabolites may be responsible for hepatic lipotoxicity and liver injury. Additional key contributors include hepatic cytosolic lipases and the "lipophagy" of lipid droplets, as sources of hepatic fatty acids. The specific origin of the lipids, mainly triacylglycerols, accumulating in liver has been unraveled by recent kinetic studies, and identifying the origin of the accumulated triacylglycerols in the liver of patients with NAFLD may direct the prevention and treatment of this condition.
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Affiliation(s)
- David Q-H Wang
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St. Louis, Missouri
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72
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Bochkis IM, Przybylski D, Chen J, Regev A. Changes in nucleosome occupancy associated with metabolic alterations in aged mammalian liver. Cell Rep 2014; 9:996-1006. [PMID: 25437555 PMCID: PMC4250828 DOI: 10.1016/j.celrep.2014.09.048] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/15/2014] [Accepted: 09/24/2014] [Indexed: 12/27/2022] Open
Abstract
Aging is accompanied by physiological impairments, which, in insulin-responsive tissues, including the liver, predispose individuals to metabolic disease. However, the molecular mechanisms underlying these changes remain largely unknown. Here, we analyze genome-wide profiles of RNA and chromatin organization in the liver of young (3 months) and old (21 months) mice. Transcriptional changes suggest that derepression of the nuclear receptors PPARα, PPARγ, and LXRα in aged mouse liver leads to activation of targets regulating lipid synthesis and storage, whereas age-dependent changes in nucleosome occupancy are associated with binding sites for both known regulators (forkhead factors and nuclear receptors) and candidates associated with nuclear lamina (Hdac3 and Srf) implicated to govern metabolic function of aging liver. Winged-helix transcription factor Foxa2 and nuclear receptor corepressor Hdac3 exhibit a reciprocal binding pattern at PPARα targets contributing to gene expression changes that lead to steatosis in aged liver.
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Affiliation(s)
- Irina M Bochkis
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | | | - Jenny Chen
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Aviv Regev
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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73
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Effects of pioglitazone mediated activation of PPAR-γ on CIDEC and obesity related changes in mice. PLoS One 2014; 9:e106992. [PMID: 25210844 PMCID: PMC4161383 DOI: 10.1371/journal.pone.0106992] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 08/08/2014] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE Obesity is a metabolic disorder that can lead to high blood pressure, increased blood cholesterol and triglycerides, insulin resistance, and diabetes mellitus. The aim was to study the effects of pioglitazone mediated sensitization of peroxisome proliferator-activated receptor gamma (PPAR-γ) on the relationship of Cell death-inducing DFFA-like effector C (CIDEC) with obesity related changes in mice. METHODS Sixty C57B/L6 mice weighing 10-12g at 3 weeks of age were randomly divided into 3 groups. Mice in Group 1 were fed on normal diet (ND) while Group 2 mice were given high fat diet (HFD), and Group 3 mice were given high fat diet and treated with Pioglitazone (HFD+P). Body weight, length and level of blood sugar were measured weekly. Quantitative real-time PCR, fluorescence microscopy, and ELISA were performed to analyze the expression of CIDEC and PPAR-γ in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). RESULTS Body weight and length of mice increased gradually with time in all groups. Blood sugar in HFD mice started to increase significantly from the mid of late phase of obesity while pioglitazone attenuated blood sugar level in HFD+P mice. The mRNA expressions and protein levels of PPAR-γ and CIDEC genes started to increase in HFD mice as compared to ND mice and decreased gradually during the late phase of obesity in VAT. Pioglitazone enhanced the expression of PPAR-γ and CIDEC genes in HFD+P mice even during the late phase of obesity. CONCLUSION It is insinuated that VAT is associated with late phase obesity CIDEC decrease and insulin resistance, while pioglitazone enhances CIDEC through activation of PPAR-γ, increases its expression, and decreases lipolysis, hence preventing an increase of blood sugar in mice exposed to HFD.
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74
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Singaravelu R, Delcorde J, Lyn RK, Steenbergen RH, Jones DM, Tyrrell DL, Russell RS, Pezacki JP. Investigating the antiviral role of cell death-inducing DFF45-like effector B in HCV replication. FEBS J 2014; 281:3751-65. [PMID: 24980280 DOI: 10.1111/febs.12901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 06/25/2014] [Accepted: 06/27/2014] [Indexed: 12/16/2022]
Abstract
Cell-death-inducing DFF45-like effector B (CIDEB) is an apoptotic host factor, which was recently found to also regulate hepatic lipid homeostasis. Herein we delineate the relevance of these dual roles of CIDEB in apoptosis and lipid metabolism in the context of hepatitis C virus (HCV) replication. We demonstrate that HCV upregulates CIDEB expression in human serum differentiated hepatoma cells. CIDEB overexpression inhibits HCV replication in HCV replicon expressing Huh7.5 cells, while small interfering RNA knockdown of CIDEB expression in human serum differentiated hepatoma cells promotes HCV replication and secretion of viral proteins. Furthermore, we characterize a CIDEB mutant, KRRA, which is deficient in lipid droplet clustering and fusion and demonstrate that CIDEB-mediated inhibition of HCV is independent of the protein's lipid droplet fusogenic role. Our results suggest that higher levels of CIDEB expression, which favour an apoptotic role for the host factor, inhibit HCV. Collectively, our data demonstrate that CIDEB can act as an anti-HCV host factor and contribute to altered triglyceride homeostasis.
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Affiliation(s)
- Ragunath Singaravelu
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ontario, Canada; National Research Council of Canada, Ottawa, Ontario, Canada
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Montastier E, Déjean S, Le Gall C, Saris WHM, Langin D, Viguerie N. Adipose tissue CIDEA is associated, independently of weight variation, to change in insulin resistance during a longitudinal weight control dietary program in obese individuals. PLoS One 2014; 9:e98707. [PMID: 24983748 PMCID: PMC4077708 DOI: 10.1371/journal.pone.0098707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/30/2014] [Indexed: 02/05/2023] Open
Abstract
AIM Weight loss reduces risk factors associated with obesity. However, long-term metabolic improvement remains a challenge. We investigated quantitative gene expression of subcutaneous adipose tissue in obese individuals and its relationship with low calorie diet and long term weight maintenance induced changes in insulin resistance. RESEARCH DESIGN Three hundred eleven overweight and obese individuals followed a dietary protocol consisting of an 8-week low calorie diet followed by a 6-month ad libitum weight-maintenance diet. Individuals were clustered according to insulin resistance trajectories assessed using homeostasis model assessment of insulin resistance (HOMA-IR) index. Adipose tissue mRNA levels of 267 genes selected for regulation according to obesity, metabolic status and response to dieting was assessed using high throughput RT-qPCR. A combination of discriminant analyses was used to identify genes with regulation according to insulin resistance trajectories. Partial correlation was used to control for change in body mass index. RESULTS Three different HOMA-IR profile groups were determined. HOMA-IR improved during low calorie diet in the 3 groups. At the end of the 6-month follow-up, groups A and B had reduced HOMA-IR by 50%. In group C, HOMA-IR had returned to baseline values. Genes were differentially expressed in the adipose tissue of individuals according to groups but a single gene, CIDEA, was common to all phases of the dietary intervention. Changes in adipose tissue CIDEA mRNA levels paralleled variations in insulin sensitivity independently of change in body mass index. Overall, CIDEA was up-regulated in adipose tissue of individuals with successful long term insulin resistance relapse and not in adipose tissue of unsuccessful individuals. CONCLUSION The concomitant change in adipose tissue CIDEA mRNA levels and insulin sensitivity suggests a beneficial role of adipose tissue CIDEA in long term glucose homeostasis, independently of weight variation. TRIAL REGISTRATION ClinicalTrials.gov NCT00390637.
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Affiliation(s)
- Emilie Montastier
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases (I2MC), Toulouse, France
- University of Toulouse, UMR1048, Paul Sabatier University, Toulouse, France
- Toulouse University Hospitals, Departments of Clinical Biochemistry, Toulouse, France
| | - Sébastien Déjean
- Toulouse University, Institut de Mathématiques UMR CNRS 5219, Toulouse, France
| | - Caroline Le Gall
- Toulouse University, Institut de Mathématiques UMR CNRS 5219, Toulouse, France
| | - Wim H. M. Saris
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Dominique Langin
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases (I2MC), Toulouse, France
- University of Toulouse, UMR1048, Paul Sabatier University, Toulouse, France
- Toulouse University Hospitals, Departments of Clinical Biochemistry, Toulouse, France
| | - Nathalie Viguerie
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases (I2MC), Toulouse, France
- University of Toulouse, UMR1048, Paul Sabatier University, Toulouse, France
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76
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DNA microarray analysis of genes differentially expressed in adipocyte differentiation. J Biosci 2014; 39:415-23. [DOI: 10.1007/s12038-014-9412-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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77
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Carr SK, Chen JH, Cooper WN, Constância M, Yeo GSH, Ozanne SE. Maternal diet amplifies the hepatic aging trajectory of Cidea in male mice and leads to the development of fatty liver. FASEB J 2014; 28:2191-201. [PMID: 24481968 DOI: 10.1096/fj.13-242727] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The importance of the early environment on long-term heath and life span is well documented. However, the molecular mechanisms mediating these effects remain poorly understood. Male offspring from a maternal protein restriction model, in which animals are exposed to a low-protein diet while in utero and then are cross-fostered to normally fed dams, demonstrate low birth weight, catch-up growth, and reduced life span (recuperated offspring). In the current study, we used microarray analysis to identify hepatic genes that changed with age. Cell death-inducing DNA fragmentation factor, α subunit-like effector A (Cidea), a transcriptional coactivator that has been implicated in lipid accumulation demonstrated one of the largest age-associated increases in expression (200-fold, P<0.001). This increase was exaggerated ∼3-fold in recuperated offspring. These demonstrated increased hepatic lipid accumulation, higher levels of transcription factors important in lipid regulation, and greater oxidative stress. In vitro analysis revealed that Cidea expression was regulated by oxidative stress and DNA methylation. These findings suggest that maternal diet modulates the age-associated changes in Cidea expression through several mechanisms. This expression affects hepatic lipid metabolism in these animals and thus provides a mechanism by which maternal diet can contribute to the metabolic health and ultimately the life span of the offspring.
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Affiliation(s)
- Sarah K Carr
- 1University of Cambridge Metabolic Research Laboratories, MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge CB2 OQQ, UK.
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78
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Barber E, Sinclair AJ, Cameron-Smith D. Comparative actions of omega-3 fatty acids on in-vitro lipid droplet formation. Prostaglandins Leukot Essent Fatty Acids 2013; 89:359-66. [PMID: 24012207 DOI: 10.1016/j.plefa.2013.07.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 07/18/2013] [Accepted: 07/25/2013] [Indexed: 01/24/2023]
Abstract
Storage of fat into lipid droplets (LDs) is the key step in adipogenesis. Previously the omega-3 polyunsaturated fatty acid (n-3PUFA) eicosapentaenoic acid (EPA; C20:5n-3) has been shown to suppress LD formation, yet the actions of other n-3PUFA is unknown. Here, we examined the impact of the three major long chain n-3PUFA; EPA, docosapentaenoic acid (DPA; C22:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) on LD formation in 3T3-L1 adipocytes. Cells were supplemented with 100µM fatty acid during differentiation. All n-3PUFA significantly reduced LD formation and the metabolic disorder marker, SCD1, in comparison to stearic acid (STA; C18:0). This action was more potent for DHA than either EPA or DPA. Furthermore, DHA significantly increased lipolysis and ATGL gene and protein expression but reduced the gene expression of three proteins related to LD formation (Perilipin A, Caveolin-1 and Cidea), compared with other n-3PUFA. Thus, DHA, above EPA and DPA, markedly suppressed fat storage in LDs in in-vitro adipocytes.
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Affiliation(s)
- Elizabeth Barber
- Department of Nutrition and Dietetics, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton 3800, Victoria, Australia.
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79
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Wang J, Cao X, Pan H, Hua L, Yang M, Lei C, Lan X, Chen H. Cell death-inducing DFFA-like effector c (CIDEC/Fsp27) gene: molecular cloning, sequence characterization, tissue distribution and polymorphisms in Chinese cattles. Mol Biol Rep 2013; 40:6765-74. [PMID: 24065549 DOI: 10.1007/s11033-013-2793-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 09/14/2013] [Indexed: 12/17/2022]
Abstract
Cell death-inducing DFFA-like effector c (CIDEC) protein, also known as fat specific protein 27 (Fsp27), is localized to lipid droplets. CIDEC protein is required for unilocular lipid droplet formation and optimal energy storage in addition to controlling lipid metabolism in adipocytes and hepatocytes. Research found that Ad-36 could induce lipid droplets in the cultured skeletal muscle cells and this process may be mediated by promoting CIDEC expression. The content of intermuscular fat is an important index for evaluation of beef quality, so the CIDEC gene appeared to be a candidate gene for regulation of intermuscular fat, however similar research for the bovine CIDEC gene is lacking. This paper examined the tissue expression profile of CIDEC gene in cattle using real-time RT-PCR to suggest that bovine CIDEC is highly expressed in adipose tissue. In addition, the Bovine CIDEC gene was cloned and inserted into the eukaryotic expression vector pET-28a(+), whereupon recombinant bovine CIDEC protein was induced and identified by Western-blot. A phylogenetic analysis showed that the animo acid sequence of bovine CIDEC was closer to mammalian CIDEC than rasorial CIDEC. We found ten single nucleotide polymorphisms sites (SNPs) in bovine CIDEC gene, of which SNP 2, 3, 4, 6 and 9, and SNP 8 and 10 were in complete linkage disequilibrium, respectively. SNP 1, 2 and 10 were used in further haplotype studies. Eight different haplotypes were identified in 973 cattle, of which haplotype 8 predominated with frequencies ranging from 42.90 to 54.30 %. This research provides a basis for future functional studies of CIDEC in cattle.
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Affiliation(s)
- Jing Wang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, China,
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80
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Song Y, Zhang LJ, Li H, Gu Y, Li FF, Jiang LN, Liu F, Ye J, Li Q. Polyunsaturated fatty acid relatively decreases cholesterol content in THP-1 macrophage-derived foam cell: partly correlates with expression profile of CIDE and PAT members. Lipids Health Dis 2013; 12:111. [PMID: 23879935 PMCID: PMC3751560 DOI: 10.1186/1476-511x-12-111] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 07/22/2013] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Polyunsaturated fatty acids (PUFAs) have positive effect on the regulation of plasma lipids. But the mechanism for them to modulate lipid homeostasis in macrophage is still unclear. In this study, we employed PUFA to pretreat macrophages and evaluated the variations of lipid droplet (LD) content, lipid composition, and expressions of LD-associated genes in macrophage-derived foam cells. METHOD THP-1-derived macrophages or human peripheral blood monocyte-derived macrophages were pre-treated with four non-esterified fatty acids (NEFAs) separately: saturated fatty acid (SFA)-palmitic acid (PA), monounsaturated fatty acids (MUFAs)-oleic acid (OA), PUFAs-linoleic acid (LA) and eicosapentaenoic acid (EPA). Intracellular lipid content and cholesterol efflux were analyzed in THP-1 macrophage-derived foam cells. Related gene expressions were detected by quantitative real-time PCR. RESULTS PUFA pre-treatment reduced cholesterol content in foam cells and increased cholesterol efflux to lipid-free apoAI in conditioned medium compared with PA or OA group. Cell death-inducing DFF45 like effector (CIDE) and Perilipin-Adipophilin-TIP47 (PAT) family members, as LD-associated proteins, showed specific gene expression profiles after PUFA pre-treatment. These results may help to explain the process of lipid metabolism within foam cells. CONCLUSION PUFA (LA or EPA) had a potential protective effect against cholesterol accumulation. The specific expressions of CIDE and PAT genes may provide clues to explore the protective mechanism of PUFA in foam cells.
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Affiliation(s)
- Yue Song
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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81
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Borén J, Taskinen MR, Olofsson SO, Levin M. Ectopic lipid storage and insulin resistance: a harmful relationship. J Intern Med 2013; 274:25-40. [PMID: 23551521 DOI: 10.1111/joim.12071] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Obesity increases the risk of metabolic diseases, including insulin resistance and type 2 diabetes, as well as cardiovascular disease. In addition to lipid accumulation in adipose tissue, obesity is associated with increased lipid storage in ectopic tissues, such as skeletal muscle and liver. Furthermore, lipid accumulation in the heart may result in cardiac dysfunction and heart failure. It has recently been demonstrated that intracellular lipid accumulation in ectopic tissues leads to pathological responses and impaired insulin signalling. Here, we will review the current understanding of how lipid storage and lipid droplet physiology affect the risk of developing metabolic diseases.
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Affiliation(s)
- J Borén
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden.
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82
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Krahmer N, Farese RV, Walther TC. Balancing the fat: lipid droplets and human disease. EMBO Mol Med 2013; 5:973-83. [PMID: 23740690 PMCID: PMC3721468 DOI: 10.1002/emmm.201100671] [Citation(s) in RCA: 309] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/30/2013] [Accepted: 05/02/2013] [Indexed: 01/04/2023] Open
Abstract
Lipid droplets (LDs) are dynamic, cytosolic lipid-storage organelles found in nearly all cell types. Too many or too few LDs during excess or deficient fat storage lead to many different human diseases. Recent insights into LD biology and LD protein functions shed new light on mechanisms underlying those metabolic pathologies. These findings will likely provide opportunities for treatment of diseases associated with too much or too little fat.
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Affiliation(s)
- Natalie Krahmer
- Department of Cell Biology, Yale School of MedicineNew Haven, CT, USA
| | - Robert V Farese
- Gladstone Institutes, Departments of Medicine and Biochemistry & Biophysics, University of CaliforniaSan Francisco, CA, USA
| | - Tobias C Walther
- Department of Cell Biology, Yale School of MedicineNew Haven, CT, USA
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83
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Perilipin1 promotes unilocular lipid droplet formation through the activation of Fsp27 in adipocytes. Nat Commun 2013; 4:1594. [PMID: 23481402 PMCID: PMC3615468 DOI: 10.1038/ncomms2581] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 02/06/2013] [Indexed: 12/25/2022] Open
Abstract
Mature white adipocytes contain a characteristic unilocular lipid droplet. However, the molecular mechanisms underlying unilocular lipid droplet formation are poorly understood. We previously showed that Fsp27, an adipocyte-specific lipid droplet-associated protein, promotes lipid droplet growth by initiating lipid exchange and transfer. Here, we identify Perilipin1 (Plin1), another adipocyte-specific lipid droplet-associated protein, as an Fsp27 activator. Plin1 interacts with the CIDE-N domain of Fsp27 and markedly increases Fsp27-mediated lipid exchange, lipid transfer and lipid droplet growth. Functional cooperation between Plin1 and Fsp27 is required for efficient lipid droplet growth in adipocytes, as depletion of either protein impairs lipid droplet growth. The CIDE-N domain of Fsp27 forms homodimers and disruption of CIDE-N homodimerization abolishes Fsp27-mediated lipid exchange and transfer. Interestingly, Plin1 can restore the activity of CIDE-N homodimerization-defective mutants of Fsp27. We thus uncover a novel mechanism underlying lipid droplet growth and unilocular lipid droplet formation that involves the cooperative action of Fsp27 and Plin1 in adipocytes. Adipocytes store lipid in spherical droplets whose size is determined by lipid exchange and transfer proteins. Sun et al. show that Perilipin1 promotes the growth of lipid droplets by activating the lipid transfer protein Fsp27.
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84
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Konige M, Wang H, Sztalryd C. Role of adipose specific lipid droplet proteins in maintaining whole body energy homeostasis. Biochim Biophys Acta Mol Basis Dis 2013; 1842:393-401. [PMID: 23688782 DOI: 10.1016/j.bbadis.2013.05.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 04/10/2013] [Accepted: 05/03/2013] [Indexed: 12/15/2022]
Abstract
Excess or insufficient lipid storage in white adipose tissue lipid droplets is associated with dyslipidemia, insulin resistance and increased risk for diabetes type 2. Thus, maintenance of adipose lipid droplet growth and function is critical to preserve whole body insulin sensitivity and energy homeostasis. Progress in understanding biology of lipid droplets has underscored the role of proteins that interact with lipid droplets. Here, we review the current knowledge of adipose specific lipid droplet proteins, which share unique functions controlling adipocyte lipid storage, limiting lipid spill-over and lipotoxic effects thought to contribute to disease. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.
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Affiliation(s)
- Manige Konige
- Department of Medicine, Division of Endocrinology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Hong Wang
- Department of Medicine, Division of Endocrinology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Carole Sztalryd
- Department of Medicine, Division of Endocrinology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA; Geriatric Research, Education, and Clinical Center, Baltimore Veterans Affairs Health Care Center, Baltimore, MD 21201, USA.
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85
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Parasitic nematode-induced modulation of body weight and associated metabolic dysfunction in mouse models of obesity. Infect Immun 2013; 81:1905-14. [PMID: 23509143 DOI: 10.1128/iai.00053-13] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Obesity is associated with a chronic low-grade inflammation characterized by increased levels of proinflammatory cytokines that are implicated in disrupted metabolic homeostasis. Parasitic nematode infection induces a polarized Th2 cytokine response and has been explored to treat autoimmune diseases. We investigated the effects of nematode infection against obesity and the associated metabolic dysfunction. Infection of RIP2-Opa1KO mice or C57BL/6 mice fed a high-fat diet (HFD) with Nippostrongylus brasiliensis decreased weight gain and was associated with improved glucose metabolism. Infection of obese mice fed the HFD reduced body weight and adipose tissue mass, ameliorated hepatic steatosis associated with a decreased expression of key lipogenic enzymes/mediators, and improved glucose metabolism, accompanied by changes in the profile of metabolic hormones. The infection resulted in a phenotypic change in adipose tissue macrophages that was characterized by upregulation of alternative activation markers. Interleukin-13 (IL-13) activation of the STAT6 signaling pathway was required for the infection-induced attenuation of steatosis but not for improved glucose metabolism, whereas weight loss was attributed to both IL-13/STAT6-dependent and -independent mechanisms. Parasitic nematode infection has both preventive and therapeutic effects against the development of obesity and associated features of metabolic dysfunction in mice.
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86
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Yu M, Wang H, Zhao J, Yuan Y, Wang C, Li J, Zhang L, Zhang L, Li Q, Ye J. Expression of CIDE proteins in clear cell renal cell carcinoma and their prognostic significance. Mol Cell Biochem 2013; 378:145-51. [PMID: 23475172 PMCID: PMC3634988 DOI: 10.1007/s11010-013-1605-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 02/23/2013] [Indexed: 01/03/2023]
Abstract
Clear cell renal cell carcinoma (ccRCC) is the major and aggressive subtype of renal cell carcinoma. It is known to derive its histologic appearance from accumulation of abundant lipids and glycogens. The cell death-inducing DFF45-like effector (CIDE) family has been characterized as the lipid droplet proteins involved in the metabolism of lipid storage droplets. The purpose of this study was to evaluate the expression of CIDE proteins in ccRCC cells and to investigate their prognostic significance. We examined consecutive patients with sporadic ccRCC, who underwent nephrectomy, to measure their mRNA and protein expression of CIDE proteins. We found that Cidec and ADRP expression were significantly up-regulated in ccRCC, compared with normal kidney tissues. Cideb was down-regulated. We also found that Cideb was expressed more in low-grade ccRCC than in high-grade tumors. To further clarify the relationship between Cideb expression and patient prognosis, we evaluated 57 ccRCC patients followed up for 120 months. Reduced ccRCC Cideb expression was associated with a higher Fuhrman nuclear grade. Patients with high Cideb expression had better overall survival rate than those with low expression (p < 0.05). Cideb expression was an independent predictor of survival (p = 0.001). Although the biologic function of Cideb in ccRCC remains unknown, the expression level of Cideb might be a novel predictor of prognosis in ccRCC.
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Affiliation(s)
- Ming Yu
- The Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
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87
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Qiu W, Wee K, Takeda K, Lim X, Sugii S, Radda GK, Han W. Suppression of adipogenesis by pathogenic seipin mutant is associated with inflammatory response. PLoS One 2013; 8:e57874. [PMID: 23520483 PMCID: PMC3592919 DOI: 10.1371/journal.pone.0057874] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 01/29/2013] [Indexed: 02/07/2023] Open
Abstract
Background While pathogenic mutations in BSCL2/Seipin cause congenital generalized lipodystrophy, the underlying mechanism is largely unknown. In this study, we investigated whether and how the pathogenic missense A212P mutation of Seipin (Seipin-A212P) inhibits adipogenesis. Methodology/Results We analyzed gene expression and lipid accumulation in stable 3T3-L1 cell lines expressing wild type (3T3-WT), non-lipodystrophic mutants N88S (3T3-N88S) and S90L (3T3-S90L), or lipodystrophic mutant A212P Seipin (3T3-A212P). When treated with adipogenic cocktail, 3T3-WT, 3T3-N88S and 3T3-S90L cells exhibited proper differentiation into mature adipocytes, indistinguishable from control 3T3-L1 cells. In contrast, adipogenesis was significantly impaired in 3T3-A212P cells. The defective adipogenesis in 3T3-A212P cells could be partially rescued by either PPARγ agonist or PPARγ overexpression. Gene expression profiling by microarray revealed that inhibition of adipogenesis was associated with activation of inflammatory genes including IL-6 and iNOS. We further demonstrated that Seipin-A212P expression at pre-differentiation stages significantly activated inflammatory responses by using an inducible expression system. The inflammation-associated inhibition of adipogenesis could be rescued by treatment with anti-inflammatory agents. Conclusions These results suggest that pathogenic Seipin-A212P inhibits adipogenesis and the inhibition is associated with activation of inflammatory pathways at pre-differentiation stages. Use of anti-inflammatory drugs may be a potential strategy for the treatment of lipodystrophy.
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Affiliation(s)
- Wenjie Qiu
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Republic of Singapore
| | - Kenneth Wee
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Republic of Singapore
| | - Kosuke Takeda
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Republic of Singapore
| | - Xuemei Lim
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Republic of Singapore
| | - Shigeki Sugii
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Republic of Singapore
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Graduate Medical School, Singapore, Republic of Singapore
- * E-mail: (WH) (SS); (SS) (WH)
| | - George K. Radda
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Republic of Singapore
| | - Weiping Han
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Republic of Singapore
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Graduate Medical School, Singapore, Republic of Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
- Metabolism in Human Diseases, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Republic of Singapore
- * E-mail: (WH) (SS); (SS) (WH)
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88
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Kang HS, Liao G, DeGraff LM, Gerrish K, Bortner CD, Garantziotis S, Jetten AM. CD44 plays a critical role in regulating diet-induced adipose inflammation, hepatic steatosis, and insulin resistance. PLoS One 2013; 8:e58417. [PMID: 23505504 PMCID: PMC3591334 DOI: 10.1371/journal.pone.0058417] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 02/04/2013] [Indexed: 01/07/2023] Open
Abstract
CD44 is a multifunctional membrane receptor implicated in the regulation of several biological processes, including inflammation. CD44 expression is elevated in liver and white adipose tissue (WAT) during obesity suggesting a possible regulatory role for CD44 in metabolic syndrome. To study this hypothesis, we examined the effect of the loss of CD44 expression on the development of various features of metabolic syndrome using CD44 null mice. Our study demonstrates that CD44-deficient mice (CD44KO) exhibit a significantly reduced susceptibility to the development of high fat-diet (HFD)-induced hepatic steatosis, WAT-associated inflammation, and insulin resistance. The decreased expression of genes involved in fatty acid synthesis and transport (Fasn and Cd36), de novo triglyceride synthesis (Mogat1), and triglyceride accumulation (Cidea, Cidec) appears in part responsible for the reduced hepatic lipid accumulation in CD44KO(HFD) mice. In addition, the expression of various inflammatory and cell matrix genes, including several chemokines and its receptors, osteopontin, and several matrix metalloproteinases and collagen genes was greatly diminished in CD44KO(HFD) liver consistent with reduced inflammation and fibrogenesis. In contrast, lipid accumulation was significantly increased in CD44KO(HFD) WAT, whereas inflammation as indicated by the reduced infiltration of macrophages and expression of macrophage marker genes, was significantly diminished in WAT of CD44KO(HFD) mice compared to WT(HFD) mice. CD44KO(HFD) mice remained considerably more insulin sensitive and glucose tolerant than WT(HFD) mice and exhibited lower blood insulin levels. Our study indicates that CD44 plays a critical role in regulating several aspects of metabolic syndrome and may provide a new therapeutic target in the management of insulin resistance.
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Affiliation(s)
- Hong Soon Kang
- Cell Biology Section, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Grace Liao
- Cell Biology Section, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Laura M. DeGraff
- Cell Biology Section, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Kevin Gerrish
- Microarray Group, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Carl D. Bortner
- Laboratory of Signal Transduction, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Stavros Garantziotis
- Matrix Biology Section, LRB, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Anton M. Jetten
- Cell Biology Section, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
- * E-mail:
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89
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Pulido MR, Rabanal-Ruiz Y, Almabouada F, Díaz-Ruiz A, Burrell MA, Vázquez MJ, Castaño JP, Kineman RD, Luque RM, Diéguez C, Vázquez-Martínez R, Malagón MM. Nutritional, hormonal, and depot-dependent regulation of the expression of the small GTPase Rab18 in rodent adipose tissue. J Mol Endocrinol 2013; 50:19-29. [PMID: 23093555 DOI: 10.1530/jme-12-0140] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
There is increasing evidence that proteins associated with lipid droplets (LDs) play a key role in the coordination of lipid storage and mobilization in adipocytes. The small GTPase, RAB18, has been recently identified as a novel component of the protein coat of LDs and proposed to play a role in both β-adrenergic stimulation of lipolysis and insulin-induced lipogenesis in 3T3-L1 adipocytes. In order to better understand the role of Rab18 in the regulation of lipid metabolism in adipocytes, we evaluated the effects of age, fat location, metabolic status, and hormonal milieu on Rab18 expression in rodent white adipose tissue (WAT). Rab18 mRNA was undetectable at postnatal day 15 (P15), but reached adult levels by P45, in both male and female rats. In adult rats, Rab18 immunolocalized around LDs, as well as within the cytoplasm of mature adipocytes. A weak Rab18 signal was also detected in the stromal-vascular fraction of WAT. In mice, fasting significantly increased, though with a distinct time-course pattern, Rab18 mRNA and protein levels in visceral and subcutaneous WAT. The expression of Rab18 was also increased in visceral and subcutaneous WAT of obese mice (diet-induced, ob/ob, and New Zealand obese mice) compared with lean controls. Rab18 expression in rats was unaltered by castration, adrenalectomy, or GH deficiency but was increased by hypophysectomy, as well as hypothyroidism. When viewed together, our results suggest the participation of Rab18 in the regulation of lipid processing in adipose tissue under both normal and pathological conditions.
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Affiliation(s)
- Marina R Pulido
- Department of Cell Biology, Physiology and Immunology, Instituto Maimónides de Investigación Biomédica de Córdoba, University of Córdoba/Hospital Universitario Reina Sofia, Edificio Severo-Ochoa, Pl. 3, Campus Univ. de Rabanales, E-14014 Córdoba, Spain
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90
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Tiwari S, Siddiqi S, Siddiqi SA. CideB protein is required for the biogenesis of very low density lipoprotein (VLDL) transport vesicle. J Biol Chem 2013; 288:5157-65. [PMID: 23297397 DOI: 10.1074/jbc.m112.434258] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Nascent very low density lipoprotein (VLDL) exits the endoplasmic reticulum (ER) in a specialized ER-derived vesicle, the VLDL transport vesicle (VTV). Similar to protein transport vesicles (PTVs), VTVs require coat complex II (COPII) proteins for their biogenesis from the ER membranes. Because the size of the VTV is large, we hypothesized that protein(s) in addition to COPII components might be required for VTV biogenesis. Our proteomic analysis, supported by Western blotting data, shows that a 26-kDa protein, CideB, is present in the VTV but not in other ER-derived vesicles such as PTV and pre-chylomicron transport vesicle. Western blotting and immunoelectron microscopy analyses suggest that CideB is concentrated in the VTV. Our co-immunoprecipitation data revealed that CideB specifically interacts with VLDL structural protein, apolipoprotein B100 (apoB100), but not with albumin, a PTV cargo protein. Confocal microscopic data indicate that CideB co-localizes with apoB100 in the ER. Additionally, CideB interacts with COPII components, Sar1 and Sec24. To investigate the role of CideB in VTV biogenesis, we performed an in vitro ER budding assay. We show that the blocking of CideB inhibits VTV budding, indicating a direct requirement of CideB in VTV formation. To confirm our findings, we knocked down CideB in primary hepatocytes and isolated ER and cytosol to examine whether they support VTV budding. Our data suggest that CideB knockdown significantly reduces VTV biogenesis. These findings suggest that CideB forms an intricate COPII coat and regulates the VTV biogenesis.
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Affiliation(s)
- Samata Tiwari
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827, USA
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91
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Abstract
Lipid droplets (LDs) are highly dynamic cellular organelles found in most eukaryotic cell types. In white adipocytes, LDs grow into a characteristic unilocular morphology that is well suited for its specialized role as an efficient energy storage organelle. Overexpansion of LDs in white adipocytes results in the development of obesity and insulin resistance. Besides its central role in lipid storage and mobilization, LDs play crucial roles in various cellular processes including virus packaging, host defense, protein storage, and degradation. CIDE proteins, in particular Fsp27, initiates a unique LD fusion process in adipocytes by clustering and enriching at LD contact site and promoting neutral lipid exchange and transfer between contacted LDs. Here, we summarize our approaches to quantitatively measure intracellular LD size and neutral lipid exchange between LDs. Utilization of these methods has greatly facilitated our understanding of molecular pathways governing LD growth in adipocytes.
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Affiliation(s)
- Zhiqi Sun
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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92
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Sun Z, Lazar MA. Dissociating fatty liver and diabetes. Trends Endocrinol Metab 2013; 24:4-12. [PMID: 23043895 PMCID: PMC3532558 DOI: 10.1016/j.tem.2012.09.005] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Revised: 09/08/2012] [Accepted: 09/10/2012] [Indexed: 12/18/2022]
Abstract
Fatty liver disease is epidemiologically associated with type 2 diabetes (T2D), leading to a speculation of a reciprocal cause-effect relationship and a vicious cycle of pathology. Here, we summarize recent literature reporting dissociation of hepatosteatosis from insulin resistance in genetic mouse models and clinical studies. We highlight rhythmic flows of metabolic intermediates between hepatic lipid synthesis and glucose production in normal circadian physiology. Blocking triglyceride (TG) secretion, subcellular lipid sequestration, lipolysis deficiency, enhanced lipogenesis, gluconeogenesis defects, or inhibition of fatty acid oxidation all result in hepatosteatosis without causing hyperglycemia or insulin resistance, suggesting that the cause-effect relationship between hepatosteatosis and diabetes does not exist in all situations.
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Affiliation(s)
- Zheng Sun
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- The Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Mitchell A. Lazar
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- The Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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93
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Jetten AM, Kang HS, Takeda Y. Retinoic acid-related orphan receptors α and γ: key regulators of lipid/glucose metabolism, inflammation, and insulin sensitivity. Front Endocrinol (Lausanne) 2013; 4:1. [PMID: 23355833 PMCID: PMC3555121 DOI: 10.3389/fendo.2013.00001] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/05/2013] [Indexed: 01/07/2023] Open
Abstract
Retinoic acid-related orphan receptors RORα and RORγ play a regulatory role in lipid/glucose homeostasis and various immune functions, and have been implicated in metabolic syndrome and several inflammatory diseases. RORα-deficient mice are protected against age- and diet-induced obesity, hepatosteatosis, and insulin resistance. The resistance to hepatosteatosis in RORα-deficient mice is related to the reduced expression of several genes regulating lipid synthesis, transport, and storage. Adipose tissue-associated inflammation, which plays a critical role in the development of insulin resistance, is considerably diminished in RORα-deficient mice as indicated by the reduced infiltration of M1 macrophages and decreased expression of many proinflammatory genes. Deficiency in RORγ also protects against diet-induced insulin resistance by a mechanism that appears different from that in RORα deficiency. Recent studies indicated that RORs provide an important link between the circadian clock machinery and its regulation of metabolic genes and metabolic syndrome. As ligand-dependent transcription factors, RORs may provide novel therapeutic targets in the management of obesity and associated metabolic diseases, including hepatosteatosis, adipose tissue-associated inflammation, and insulin resistance.
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Affiliation(s)
- Anton M. Jetten
- *Correspondence: Anton M. Jetten, Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA. e-mail:
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94
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Ueno M, Shen WJ, Patel S, Greenberg AS, Azhar S, Kraemer FB. Fat-specific protein 27 modulates nuclear factor of activated T cells 5 and the cellular response to stress. J Lipid Res 2012; 54:734-743. [PMID: 23233732 DOI: 10.1194/jlr.m033365] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fat-specific protein 27 (FSP27), a member of the cell death-inducing DNA fragmentation factor α-like effector (Cide) family, is highly expressed in adipose tissues and is a lipid droplet (LD)-associated protein that induces the accumulation of LDs. Using a yeast two-hybrid system to examine potential interactions of FSP27 with other proteins, a direct interaction with the N-terminal region of nuclear factor of activated T cells 5 (NFAT5) was identified. NFAT5 is a transcription factor that induces osmoprotective and inflammatory genes after its translocation to the nucleus. The interaction between FSP27 and NFAT5 was confirmed by bimolecular fluorescence complementation and coimmunoprecipitation. Using immunocytochemistry, NFAT5 is detected in the cytoplasm and in the nucleus under isotonic conditions; however, overexpression of FSP27 inhibited the hypertonic-induced nuclear translocation of NFAT5. Consistent with the suppression of NFAT5 nuclear translocation, in cells transfected with a reporter construct containing the NFAT5 response element from the monocyte chemoattractant protein 1 (MCP1) promoter, FSP27 overexpression repressed hypertonic-induced luciferase activity and the expression of NFAT5 target genes. Knockdown of FSP27 in differentiated 3T3-L1 adipocytes increased the NFAT5-mediated rise in MCP1. These results suggest that FSP27 not only modulates LD homeostasis but also modulates the response to osmotic stress via a physical interaction with NFAT5 at the LD surface.
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Affiliation(s)
- Masami Ueno
- Veterans Administration Palo Alto Health Care System, Palo Alto, CA, USA
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95
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Vilà-Brau A, De Sousa-Coelho AL, Gonçalves JF, Haro D, Marrero PF. Fsp27/CIDEC is a CREB target gene induced during early fasting in liver and regulated by FA oxidation rate. J Lipid Res 2012; 54:592-601. [PMID: 23220584 DOI: 10.1194/jlr.m028472] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
FSP27 [cell death-inducing DFFA-like effector c (CIDEC) in humans] is a protein associated with lipid droplets that downregulates the fatty acid oxidation (FAO) rate when it is overexpressed. However, little is known about its physiological role in liver. Here, we show that fasting regulates liver expression of Fsp27 in a time-dependent manner. Thus, during the initial stages of fasting, a maximal induction of 800-fold was achieved, whereas during the later phase of fasting, Fsp27 expression decreased. The early response to fasting can be explained by a canonical PKA-CREB-CRTC2 signaling pathway because: i) CIDEC expression was induced by forskolin, ii) Fsp27 promoter activity was increased by CREB, and iii) Fsp27 expression was upregulated in the liver of Sirt1 knockout animals. Interestingly, pharmacological (etomoxir) or genetic (Hmgcs2 interference) inhibition of the FAO rate increases the in vivo expression of Fsp27 during fasting. Similarly, CIDEC expression was upregulated in HepG2 cells by either etomoxir or HMGCS2 interference. Our data indicate that there is a kinetic mechanism of autoregulation between short- and long-term fasting, by which free FAs delivered to the liver during early fasting are accumulated/exported by FSP27/CIDEC, whereas over longer periods of fasting, they are degraded in the mitochondria through the carnitine palmitoyl transferase system.
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Affiliation(s)
- Anna Vilà-Brau
- Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona, Barcelona, Spain
| | - Ana Luísa De Sousa-Coelho
- Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona, Barcelona, Spain
| | - Joana F Gonçalves
- Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona, Barcelona, Spain
| | - Diego Haro
- Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona, Barcelona, Spain
| | - Pedro F Marrero
- Department of Biochemistry and Molecular Biology, School of Pharmacy and the Institute of Biomedicine of the University of Barcelona, Barcelona, Spain
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96
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Wang X, Zhang B, Xu D, Gao J, Wang L, Wang Z, Shan Y, Yu X. Purification, crystallization and preliminary X-ray crystallographic analysis of the CIDE-N domain of Fsp27. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012. [PMID: 23192040 DOI: 10.1107/s1744309112043989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Fsp27, a member of the CIDE protein family which is selectively expressed in adipocytes, has emerged as a novel regulator for unilocular lipid droplet (LD) formation, lipid metabolism, differentiation of adipocytes and insulin sensitivity. An LD is a subcellular compartment that is used by adipocytes for the efficient storage of fats. The CIDE-N domain of Fsp27 functions as a recruitment platform that induces the correct configuration of the Fsp27 CIDE-C domain to facilitate LD fusion. This study reports the high-yield expression of the mouse Fsp27 CIDE-N domain in Escherichia coli; a two-step purification protocol with high efficiency was established and crystallographic analysis was performed. The purity of the recombinant Fsp27 was >95% as assessed by SDS-PAGE. Crystals were obtained at 291 K using 28% polyethylene glycol 4000 as a precipitant. Diffraction data were collected to 1.92 Å resolution and the crystal belonged to space group P6(5), with unit-cell parameters a=b=63.3, c=37.4 Å, α=β=90, γ=120°. The components of the crystal were identified by ion-trap LC/MS/MS spectrometric analysis. The structure has been solved by molecular replacement and refinement is in progress.
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Affiliation(s)
- Xiaodan Wang
- National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun 130012, People's Republic of China
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97
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Sun Z, Miller RA, Patel RT, Chen J, Dhir R, Wang H, Zhang D, Graham MJ, Unterman TG, Shulman GI, Sztalryd C, Bennett MJ, Ahima RS, Birnbaum MJ, Lazar MA. Hepatic Hdac3 promotes gluconeogenesis by repressing lipid synthesis and sequestration. Nat Med 2012; 18:934-42. [PMID: 22561686 PMCID: PMC3411870 DOI: 10.1038/nm.2744] [Citation(s) in RCA: 271] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 03/16/2011] [Indexed: 12/18/2022]
Abstract
Fatty liver disease is associated with obesity and type 2 diabetes, and hepatic lipid accumulation may contribute to insulin resistance. Histone deacetylase 3 (Hdac3) controls the circadian rhythm of hepatic lipogenesis. Here we show that, despite severe hepatosteatosis, mice with liver-specific depletion of Hdac3 have higher insulin sensitivity without any changes in insulin signaling or body weight compared to wild-type mice. Hdac3 depletion reroutes metabolic precursors towards lipid synthesis and storage within lipid droplets and away from hepatic glucose production. Perilipin 2, which coats lipid droplets, is markedly induced upon Hdac3 depletion and contributes to the development of both steatosis and improved tolerance to glucose. These findings suggest that the sequestration of hepatic lipids in perilipin 2–coated droplets ameliorates insulin resistance and establish Hdac3 as a pivotal epigenomic modifier that integrates signals from the circadian clock in the regulation of hepatic intermediary metabolism.
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Affiliation(s)
- Zheng Sun
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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98
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Yang H, Galea A, Sytnyk V, Crossley M. Controlling the size of lipid droplets: lipid and protein factors. Curr Opin Cell Biol 2012; 24:509-16. [DOI: 10.1016/j.ceb.2012.05.012] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 05/23/2012] [Indexed: 01/23/2023]
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99
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Abstract
Lipid homeostasis is maintained through the coordination of lipid metabolism in various tissues, including adipose tissue and the liver. The disruption of lipid homeostasis often results in the development of metabolic disorders such as obesity, diabetes mellitus, liver steatosis, and cardiovascular diseases. Cell death-inducing DNA fragmentation factor 45-like effector family proteins, including Cidea, Cideb, and Fsp27 (Cidec), are emerging as important regulators of various lipid metabolic pathways and play pivotal roles in the development of metabolic disorders. This review summarizes the latest cell death-inducing DNA fragmentation factor 45-like effector protein discoveries related to the control of lipid metabolism, with emphasis on the role of these proteins in lipid droplet growth in adipocytes and in the regulation of very low-density lipoprotein lipidation and maturation in hepatocytes.
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Affiliation(s)
- Li Xu
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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100
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Li X, Ye J, Zhou L, Gu W, Fisher EA, Li P. Opposing roles of cell death-inducing DFF45-like effector B and perilipin 2 in controlling hepatic VLDL lipidation. J Lipid Res 2012; 53:1877-89. [PMID: 22661308 DOI: 10.1194/jlr.m026591] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Regulation of hepatic very low density lipoprotein (VLDL) assembly and maturation is crucial in controlling lipid homeostasis and in the development of metabolic disorders, including obesity, hepatic steatosis, and insulin resistance. Cideb, a member of cell death-inducing DFF45-like effector (CIDE) protein family, has been previously shown to promote VLDL lipidation and maturation. However, the precise subcellular location of Cideb-mediated VLDL lipidation and the factors modulating its activity remain elusive. In addition to its localization to endoplasmic reticulum (ER) and lipid droplets (LD), we observed that Cideb was also localized to the Golgi apparatus. Mature and lipid-rich VLDL particles did not accumulate in the Golgi apparatus in Cideb(-/-) livers. Interestingly, we observed that hepatic perilipin 2/adipose differentiation-related protein (ADRP) levels were markedly increased in Cideb(-/-) mice. Liver-specific knockdown of perilipin 2 in Cideb(-/-) mice resulted in the reduced accumulation of hepatic triglycerides (TAG), increased VLDL-TAG secretion, and the accumulation of mature TAG-rich VLDL in the Golgi apparatus. These data reveal that Cideb and perilipin 2 play opposing roles in controlling VLDL lipidation and hepatic lipid homeostasis.
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Affiliation(s)
- Xuanhe Li
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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