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Obaseki E, Adebayo D, Bandyopadhyay S, Hariri H. Lipid droplets and fatty acid-induced lipotoxicity: in a nutshell. FEBS Lett 2024; 598:1207-1214. [PMID: 38281809 PMCID: PMC11126361 DOI: 10.1002/1873-3468.14808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/02/2023] [Accepted: 01/04/2024] [Indexed: 01/30/2024]
Abstract
Lipid droplets (LDs) are fat storage organelles that are conserved from bacteria to humans. LDs are broken down to supply cells with fatty acids (FAs) that can be used as an energy source or membrane synthesis. An overload of FAs disrupts cellular functions and causes lipotoxicity. Thus, by acting as hubs for storing excess fat, LDs prevent lipotoxicity and preserve cellular homeostasis. LD synthesis and turnover have to be precisely regulated to maintain a balanced lipid distribution and allow for cellular adaptation during stress. Here, we discuss how prolonged exposure to excess lipids affects cellular functions, and the roles of LDs in buffering cellular stress focusing on lipotoxicity.
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Affiliation(s)
- Eseiwi Obaseki
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
| | - Daniel Adebayo
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
| | - Sumit Bandyopadhyay
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
| | - Hanaa Hariri
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202 USA
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2
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Cho SY, Choi JS, Jung UJ. Effects of Ecklonia stolonifera Extract on Metabolic Dysregulation in High-Fat Diet-Induced Obese Mice. J Med Food 2024; 27:242-249. [PMID: 38354279 DOI: 10.1089/jmf.2023.k.0252] [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] [Indexed: 02/16/2024] Open
Abstract
This study aimed to test the hypothesis that long-term and low-dose supplementation with an ethanol extract of Ecklonia stolonifera may confer protection against high-fat diet (HFD)-induced obesity in mice. Male C57BL/6J mice were divided into two groups, one of which was fed an HFD (40 kcal% fat) and the other an HFD+E. stolonifera (0.006%, w/w, ∼5 mg/kg body weight/day) for 16 weeks. E. stolonifera supplementation significantly reduced body weight from week 3 and until the end of the experiment. E. stolonifera-supplemented mice also exhibited lower fat mass (epididymal, perirenal, and mesenteric fat) and smaller adipocyte size than HFD control mice. The two groups displayed similar food intakes, but E. stolonifera markedly decreased lipogenesis and increased lipolysis and fatty acid oxidation in adipose tissue. Moreover, E. stolonifera significantly decreased plasma and hepatic lipid levels, hepatic lipid droplet accumulation, plasma aminotransferase levels, and liver weight by decreasing lipogenesis and increasing fatty acid oxidation. As E. stolonifera-supplemented mice showed improvements in hyperglycemia, insulin resistance, and inflammation, compared to control mice, it is possible that the beneficial effects of E. stolonifera on obesity might be associated with decreased inflammation and insulin resistance. Collectively, these results indicate that E. stolonifera could be used as a novel means of preventing and treating obesity and obesity-related metabolic disorders.
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Affiliation(s)
- Su Yeon Cho
- Department of Food Science and Nutrition, Pukyong National University, Busan, Korea
| | - Jae Sue Choi
- Department of Food Science and Nutrition, Pukyong National University, Busan, Korea
| | - Un Ju Jung
- Department of Food Science and Nutrition, Pukyong National University, Busan, Korea
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Li Y, Zhu S, Du D, Li Q, Xie K, Chen L, Feng X, Wu X, Sun Z, Zhou J, Yang J, Shu G, Wang S, Gao P, Zhu C, Jiang Q, Wang L. TLR4 in POMC neurons regulates thermogenesis in a sex-dependent manner. J Lipid Res 2023; 64:100368. [PMID: 37028769 PMCID: PMC10205441 DOI: 10.1016/j.jlr.2023.100368] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 02/10/2023] [Accepted: 03/17/2023] [Indexed: 04/08/2023] Open
Abstract
The rising prevalence of obesity has become a worldwide health concern. Obesity usually occurs when there is an imbalance between energy intake and energy expenditure. However, energy expenditure consists of several components, including metabolism, physical activity, and thermogenesis. Toll-like receptor 4 (TLR4) is a transmembrane pattern recognition receptor, and it is abundantly expressed in the brain. Here, we showed that pro-opiomelanocortin (POMC)-specific deficiency of TLR4 directly modulates brown adipose tissue thermogenesis and lipid homeostasis in a sex-dependent manner. Deleting TLR4 in POMC neurons is sufficient to increase energy expenditure and thermogenesis resulting in reduced body weight in male mice. POMC neuron is a subpopulation of tyrosine hydroxylase neurons and projects into brown adipose tissue, which regulates the activity of sympathetic nervous system and contributes to thermogenesis in POMC-TLR4-KO male mice. By contrast, deleting TLR4 in POMC neurons decreases energy expenditure and increases body weight in female mice, which affects lipolysis of white adipose tissue (WAT). Mechanistically, TLR4 KO decreases the expression of the adipose triglyceride lipase and lipolytic enzyme hormone-sensitive lipase in WAT in female mice. Furthermore, the function of immune-related signaling pathway in WAT is inhibited because of obesity, which exacerbates the development of obesity reversely. Together, these results demonstrate that TLR4 in POMC neurons regulates thermogenesis and lipid balance in a sex-dependent manner.
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Affiliation(s)
- Yongxiang Li
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Shuqing Zhu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Dan Du
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, China
| | - Qiyong Li
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Kailai Xie
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Lvshuang Chen
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiajie Feng
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xin Wu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zhonghua Sun
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Jingjing Zhou
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Jinping Yang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Gang Shu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Songbo Wang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Ping Gao
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Canjun Zhu
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China
| | - Qingyan Jiang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China.
| | - Lina Wang
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, South China Agricultural University, Guangzhou, Guangdong, China; National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China.
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Son HK, Lee J, Byun J, Lee JJ. Saccharified and Fermented Helianthus tuberosus L. Beverage Attenuates High-Fat Diet-Inducible Metabolic Complications in C57BL/6 Mice. J Med Food 2023; 26:146-161. [PMID: 36724308 DOI: 10.1089/jmf.2022.k.0098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The prevalence of obesity has been recognized as a major public health issue with rapid increase globally. Obesity triggers other metabolic complications, such as diabetes, dyslipidemia, liver diseases, and cardiovascular diseases. Helianthus tuberosus L. (the Jerusalem artichoke) is an important edible plant that may provide health benefits in treating metabolic diseases. In this study, we investigated potential antiobesity effects of saccharified H. tuberosus L. (SH) and its fermented vinegar (fermented H. tuberosus L. [FH]) in a high-fat diet (HFD)-induced obesity murine model. FH exhibited significantly lower pH, Brix, and total sugar content compared with the SH, along with higher radical-scavenging activity. The body weight and adipose tissue weights were significantly decreased with the administration of SH and FH compared with the HFD group. SH and FH groups significantly attenuated hepatomegaly and lipid accumulation. The increased triglyceride (TG) content in obese mice was remarkably lower in the SH and FH groups. SH and FH alleviated serum dyslipidemia and atherogenic risk. Furthermore, expression of adipogenic genes was significantly downregulated after SH and FH supplementation compared with the HFD group. The TG and total cholesterol (TC) content of serum and adipose tissues significantly decreased by SH and FH administration in comparison with the HFD group. Reduced adiposity with SH and FH administration was confirmed by reduced adipocyte size and weight with inhibition of lipoprotein lipase expression. Our study showed that SH and FH, indeed FH was superior to SH, had antiobesity effects by decreasing adiposity, regulating dyslipidemia in systemic tissues, and inhibiting adipogenic gene expression.
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Affiliation(s)
- Hee-Kyoung Son
- Department of Food and Nutrition, Chosun University, Gwangju, South Korea
| | - Joomin Lee
- Department of Food and Nutrition, Chosun University, Gwangju, South Korea
| | - Jaemin Byun
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Jae-Joon Lee
- Department of Food and Nutrition, Chosun University, Gwangju, South Korea
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Thermogenic Adipose Redox Mechanisms: Potential Targets for Metabolic Disease Therapies. Antioxidants (Basel) 2023; 12:antiox12010196. [PMID: 36671058 PMCID: PMC9854447 DOI: 10.3390/antiox12010196] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/07/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Metabolic diseases, such as diabetes and non-alcoholic fatty liver disease (NAFLD), have several negative health outcomes on affected humans. Dysregulated energy metabolism is a key component underlying the pathophysiology of these conditions. Adipose tissue is a fundamental regulator of energy homeostasis that utilizes several redox reactions to carry out the metabolism. Brown and beige adipose tissues, in particular, perform highly oxidative reactions during non-shivering thermogenesis to dissipate energy as heat. The appropriate regulation of energy metabolism then requires coordinated antioxidant mechanisms to counterbalance the oxidation reactions. Indeed, non-shivering thermogenesis activation can cause striking changes in concentrations of both oxidants and antioxidants in order to adapt to various oxidative environments. Current therapeutic options for metabolic diseases either translate poorly from rodent models to humans (in part due to the challenges of creating a physiologically relevant rodent model) or tend to have numerous side effects, necessitating novel therapies. As increased brown adipose tissue activity results in enhanced energy expenditure and is associated with beneficial effects on metabolic health, such as decreased obesity, it has gathered great interest as a modulator of metabolic disease. One potential reason for the beneficial health effects may be that although non-shivering thermogenesis is enormously oxidative, it is also associated with decreased oxidant formation after its activation. However, targeting its redox mechanisms specifically to alter metabolic disease remains an underexplored area. Therefore, this review will discuss the role of adipose tissue in energy homeostasis, non-shivering thermogenesis in adults, and redox mechanisms that may serve as novel therapeutic targets of metabolic disease.
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Bezawork-Geleta A, Dimou J, Watt MJ. Lipid droplets and ferroptosis as new players in brain cancer glioblastoma progression and therapeutic resistance. Front Oncol 2022; 12:1085034. [PMID: 36591531 PMCID: PMC9797845 DOI: 10.3389/fonc.2022.1085034] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 11/18/2022] [Indexed: 12/23/2022] Open
Abstract
A primary brain tumor glioblastoma is the most lethal of all cancers and remains an extremely challenging disease. Apparent oncogenic signaling in glioblastoma is genetically complex and raised at any stage of the disease's progression. Many clinical trials have shown that anticancer drugs for any specific oncogene aberrantly expressed in glioblastoma show very limited activity. Recent discoveries have highlighted that alterations in tumor metabolism also contribute to disease progression and resistance to current therapeutics for glioblastoma, implicating an alternative avenue to improve outcomes in glioblastoma patients. The roles of glucose, glutamine and tryptophan metabolism in glioblastoma pathogenesis have previously been described. This article provides an overview of the metabolic network and regulatory changes associated with lipid droplets that suppress ferroptosis. Ferroptosis is a newly discovered type of nonapoptotic programmed cell death induced by excessive lipid peroxidation. Although few studies have focused on potential correlations between tumor progression and lipid droplet abundance, there has recently been increasing interest in identifying key players in lipid droplet biology that suppress ferroptosis and whether these dependencies can be effectively exploited in cancer treatment. This article discusses how lipid droplet metabolism, including lipid synthesis, storage, and use modulates ferroptosis sensitivity or tolerance in different cancer models, focusing on glioblastoma.
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Affiliation(s)
- Ayenachew Bezawork-Geleta
- Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Melbourne, VIC, Australia,*Correspondence: Ayenachew Bezawork-Geleta,
| | - James Dimou
- Department of Surgery, The University of Melbourne, Parkville, VIC, Australia,Department of Neurosurgery, The Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Matthew J. Watt
- Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Melbourne, VIC, Australia
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Zhou H, Zhang J, Yan Z, Qu M, Zhang G, Han J, Wang F, Sun K, Wang L, Yang X. DECR1 directly activates HSL to promote lipolysis in cervical cancer cells. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159090. [PMID: 34896618 DOI: 10.1016/j.bbalip.2021.159090] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 11/29/2021] [Accepted: 12/04/2021] [Indexed: 11/30/2022]
Abstract
Fatty acids have a high turnover rate in cancer cells to supply energy for tumor growth and proliferation. Lipolysis is particularly important for the regulation of fatty acid homeostasis and in the maintenance of cancer cells. In the current study, we explored how 2,4-Dienoyl-CoA reductase (DECR1), a short-chain dehydrogenase/reductase associated with mitochondrial and cytoplasmic compartments, promotes cancer cell growth. We report that DECR1 overexpression significantly reduced the triglyceride (TAG) content in HeLa cells; conversely, DECR1 silencing increased intracellular TAG content. Subsequently, our experiments demonstrate that DECR1 promotes lipolysis via effects on hormone sensitive lipase (HSL). The direct interaction of DECR1 with HSL increases HSL phosphorylation and activity, facilitating the translocation of HSL to lipid droplets. The ensuing enhancement of lipolysis thus increases the release of free fatty acids. Downstream effects include the promotion of cervical cancer cell migration and growth, associated with the enhanced levels of p62 protein. In summary, high levels of DECR1 serves to enhance lipolysis and the release of fatty acid energy stores to support cervical cancer cell growth.
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Affiliation(s)
- Huijuan Zhou
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Jie Zhang
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - ZhongKang Yan
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Min Qu
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Gaojian Zhang
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Jianxiong Han
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Feifei Wang
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Kai Sun
- School of Life Science, Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Lili Wang
- School of Life Science, Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China
| | - Xingyuan Yang
- Institute of Physical Science and Information Technology, Institute of Health Sciences Anhui University, Hefei, Anhui Hefei, Anhui 230601, PR China.
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Li Y, Li Z, Ngandiri DA, Llerins Perez M, Wolf A, Wang Y. The Molecular Brakes of Adipose Tissue Lipolysis. Front Physiol 2022; 13:826314. [PMID: 35283787 PMCID: PMC8907745 DOI: 10.3389/fphys.2022.826314] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/10/2022] [Indexed: 12/11/2022] Open
Abstract
Adaptation to changes in energy availability is pivotal for the survival of animals. Adipose tissue, the body’s largest reservoir of energy and a major source of metabolic fuel, exerts a buffering function for fluctuations in nutrient availability. This functional plasticity ranges from energy storage in the form of triglycerides during periods of excess energy intake to energy mobilization via lipolysis in the form of free fatty acids for other organs during states of energy demands. The subtle balance between energy storage and mobilization is important for whole-body energy homeostasis; its disruption has been implicated as contributing to the development of insulin resistance, type 2 diabetes and cancer cachexia. As a result, adipocyte lipolysis is tightly regulated by complex regulatory mechanisms involving lipases and hormonal and biochemical signals that have opposing effects. In thermogenic brown and brite adipocytes, lipolysis stimulation is the canonical way for the activation of non-shivering thermogenesis. Lipolysis proceeds in an orderly and delicately regulated manner, with stimulation through cell-surface receptors via neurotransmitters, hormones, and autocrine/paracrine factors that activate various intracellular signal transduction pathways and increase kinase activity. The subsequent phosphorylation of perilipins, lipases, and cofactors initiates the translocation of key lipases from the cytoplasm to lipid droplets and enables protein-protein interactions to assemble the lipolytic machinery on the scaffolding perilipins at the surface of lipid droplets. Although activation of lipolysis has been well studied, the feedback fine-tuning is less well appreciated. This review focuses on the molecular brakes of lipolysis and discusses some of the divergent fine-tuning strategies in the negative feedback regulation of lipolysis, including delicate negative feedback loops, intermediary lipid metabolites-mediated allosteric regulation and dynamic protein–protein interactions. As aberrant adipocyte lipolysis is involved in various metabolic diseases and releasing the brakes on lipolysis in thermogenic adipocytes may activate thermogenesis, targeting adipocyte lipolysis is thus of therapeutic interest.
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Kuentzel KB, Bradić I, Akhmetshina A, Korbelius M, Rainer S, Kolb D, Gauster M, Vujić N, Kratky D. Defective Lysosomal Lipolysis Causes Prenatal Lipid Accumulation and Exacerbates Immediately after Birth. Int J Mol Sci 2021; 22:10416. [PMID: 34638755 PMCID: PMC8508985 DOI: 10.3390/ijms221910416] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/24/2021] [Accepted: 09/24/2021] [Indexed: 12/03/2022] Open
Abstract
Cholesterol and fatty acids are essential lipids that are critical for membrane biosynthesis and fetal organ development. Cholesteryl esters (CE) are degraded by hormone-sensitive lipase (HSL) in the cytosol and by lysosomal acid lipase (LAL) in the lysosome. Impaired LAL or HSL activity causes rare pathologies in humans, with HSL deficiency presenting less severe clinical manifestations. The infantile form of LAL deficiency, a lysosomal lipid storage disorder, leads to premature death. However, the importance of defective lysosomal CE degradation and its consequences during early life are incompletely understood. We therefore investigated how defective CE catabolism affects fetus and infant maturation using Lal and Hsl knockout (-/-) mouse models. This study demonstrates that defective lysosomal but not neutral lipolysis alters placental and fetal cholesterol homeostasis and exhibits an initial disease pathology already in utero as Lal-/- fetuses accumulate hepatic lysosomal lipids. Immediately after birth, LAL deficiency exacerbates with massive hepatic lysosomal lipid accumulation, which continues to worsen into young adulthood. Our data highlight the crucial role of LAL during early development, with the first weeks after birth being critical for aggravating LAL deficiency.
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Affiliation(s)
- Katharina B. Kuentzel
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (K.B.K.); (I.B.); (A.A.); (M.K.); (S.R.); (N.V.)
| | - Ivan Bradić
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (K.B.K.); (I.B.); (A.A.); (M.K.); (S.R.); (N.V.)
| | - Alena Akhmetshina
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (K.B.K.); (I.B.); (A.A.); (M.K.); (S.R.); (N.V.)
| | - Melanie Korbelius
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (K.B.K.); (I.B.); (A.A.); (M.K.); (S.R.); (N.V.)
| | - Silvia Rainer
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (K.B.K.); (I.B.); (A.A.); (M.K.); (S.R.); (N.V.)
| | - Dagmar Kolb
- Gottfried Schatz Research Center, Cell Biology, Histology and Embryology, Medical University of Graz, 8010 Graz, Austria; (D.K.); (M.G.)
- Core Facility Ultrastructural Analysis, Medical University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Martin Gauster
- Gottfried Schatz Research Center, Cell Biology, Histology and Embryology, Medical University of Graz, 8010 Graz, Austria; (D.K.); (M.G.)
| | - Nemanja Vujić
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (K.B.K.); (I.B.); (A.A.); (M.K.); (S.R.); (N.V.)
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (K.B.K.); (I.B.); (A.A.); (M.K.); (S.R.); (N.V.)
- BioTechMed-Graz, 8010 Graz, Austria
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Banakar F, Ebrahim-Habibi A, Mohammad-Amoli M, Kheirbakhsh R, Sadeghi-Afjeh M, Shahriari S, Larijani B. Hydro alcoholic green tea extract effect on high fat diet treated NMRI mice and 3T3L1 cells. J Diabetes Metab Disord 2021; 20:641-648. [PMID: 34178857 DOI: 10.1007/s40200-021-00794-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 04/04/2021] [Indexed: 11/29/2022]
Abstract
Purpose In order to counteract the obesity has epidemics, since current anti-obesity drugs effects remain limited, there is a need to provide new options. As a project aiming to assess potential anti obesity natural compounds, the effects of consumption of a minimal dose of green tea hydro alcoholic extract (GT) on adipocyte differentiation of 3T3L1 cell line were investigated. Methods Obesity was induced in female NMRI mice (which are less used overall) by the use of a high fat diet. Mice were divided into four groups of control (C), treated control (TC), obese (O) and treated obese (TO). TC and TO groups received 8 mg/Kg/day of GT for 8 weeks, and weighted weekly, after what biochemical and histological parameters were measured. GT was used at doses of 100,150 and 200 µg/ml on 3T3L1, and staining with Oil-red-O was done for estimation of fat droplet accumulation. Results Body weight was found to be affected significantly by GT. Blood glucose levels did not show significant changes between groups, while triglycerides levels of the O group was significantly higher than the C group, but the TO group showed no significant difference with the C group upon GT treatment. Liver and visceral fat tissues showed more normalized tissue and less fat accumulation in the TO group. TO and TC groups showed an ameliorated morphologic state of liver tissues. GT was also able to decrease fat droplet formation in a dose-dependent manner. Conclusions Adding a minimal amount of GT to the daily consumption may have preventive effects on fat accumulation in healthy subjects, while in obese cases, GT shows significant therapeutic effect.
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Affiliation(s)
- Farnaz Banakar
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism - Clinical Sciences Institute, Tehran University of Medical Sciences, Jalal-al-Ahmad Street, Chamran Highway, 1411713137 Tehran, Iran.,Biosensor Research Center, Endocrinology and Metabolism Molecular -Cellular Sciences Institute, Tehran University of Medical Sciences, Jalal-al-Ahmad Street, Chamran Highway, 1411713137 Tehran, Iran
| | - Azadeh Ebrahim-Habibi
- Biosensor Research Center, Endocrinology and Metabolism Molecular -Cellular Sciences Institute, Tehran University of Medical Sciences, Jalal-al-Ahmad Street, Chamran Highway, 1411713137 Tehran, Iran
| | - Mahsa Mohammad-Amoli
- Metabolic Disorders Research Centre, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Raheleh Kheirbakhsh
- Cancer Biology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Sadeghi-Afjeh
- Food and Drug Research Laboratory, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Shadab Shahriari
- Metabolic Disorders Research Centre, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Bagher Larijani
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism - Clinical Sciences Institute, Tehran University of Medical Sciences, Jalal-al-Ahmad Street, Chamran Highway, 1411713137 Tehran, Iran
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11
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SR-BI deficiency disassociates obesity from hepatic steatosis and glucose intolerance development in high fat diet-fed mice. J Nutr Biochem 2021; 89:108564. [DOI: 10.1016/j.jnutbio.2020.108564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023]
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12
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Heier C, Knittelfelder O, Hofbauer HF, Mende W, Pörnbacher I, Schiller L, Schoiswohl G, Xie H, Grönke S, Shevchenko A, Kühnlein RP. Hormone-sensitive lipase couples intergenerational sterol metabolism to reproductive success. eLife 2021; 10:63252. [PMID: 33538247 PMCID: PMC7880688 DOI: 10.7554/elife.63252] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/03/2021] [Indexed: 12/13/2022] Open
Abstract
Triacylglycerol (TG) and steryl ester (SE) lipid storage is a universal strategy to maintain organismal energy and membrane homeostasis. Cycles of building and mobilizing storage fat are fundamental in (re)distributing lipid substrates between tissues or to progress ontogenetic transitions. In this study, we show that Hormone-sensitive lipase (Hsl) specifically controls SE mobilization to initiate intergenerational sterol transfer in Drosophila melanogaster. Tissue-autonomous Hsl functions in the maternal fat body and germline coordinately prevent adult SE overstorage and maximize sterol allocation to embryos. While Hsl-deficiency is largely dispensable for normal development on sterol-rich diets, animals depend on adipocyte Hsl for optimal fecundity when dietary sterol becomes limiting. Notably, accumulation of SE but not of TG is a characteristic of Hsl-deficient cells across phyla including murine white adipocytes. In summary, we identified Hsl as an ancestral regulator of SE degradation, which improves intergenerational sterol transfer and reproductive success in flies.
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Affiliation(s)
- Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Oskar Knittelfelder
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Harald F Hofbauer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Wolfgang Mende
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Ingrid Pörnbacher
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Laura Schiller
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Gabriele Schoiswohl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Hao Xie
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Sebastian Grönke
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Andrej Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Ronald P Kühnlein
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria.,Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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13
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Adipocyte lipolysis: from molecular mechanisms of regulation to disease and therapeutics. Biochem J 2020; 477:985-1008. [PMID: 32168372 DOI: 10.1042/bcj20190468] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/19/2020] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
Abstract
Fatty acids (FAs) are stored safely in the form of triacylglycerol (TAG) in lipid droplet (LD) organelles by professional storage cells called adipocytes. These lipids are mobilized during adipocyte lipolysis, the fundamental process of hydrolyzing TAG to FAs for internal or systemic energy use. Our understanding of adipocyte lipolysis has greatly increased over the past 50 years from a basic enzymatic process to a dynamic regulatory one, involving the assembly and disassembly of protein complexes on the surface of LDs. These dynamic interactions are regulated by hormonal signals such as catecholamines and insulin which have opposing effects on lipolysis. Upon stimulation, patatin-like phospholipase domain containing 2 (PNPLA2)/adipocyte triglyceride lipase (ATGL), the rate limiting enzyme for TAG hydrolysis, is activated by the interaction with its co-activator, alpha/beta hydrolase domain-containing protein 5 (ABHD5), which is normally bound to perilipin 1 (PLIN1). Recently identified negative regulators of lipolysis include G0/G1 switch gene 2 (G0S2) and PNPLA3 which interact with PNPLA2 and ABHD5, respectively. This review focuses on the dynamic protein-protein interactions involved in lipolysis and discusses some of the emerging concepts in the control of lipolysis that include allosteric regulation and protein turnover. Furthermore, recent research demonstrates that many of the proteins involved in adipocyte lipolysis are multifunctional enzymes and that lipolysis can mediate homeostatic metabolic signals at both the cellular and whole-body level to promote inter-organ communication. Finally, adipocyte lipolysis is involved in various diseases such as cancer, type 2 diabetes and fatty liver disease, and targeting adipocyte lipolysis is of therapeutic interest.
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14
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Cheng Y, Gan-Schreier H, Seeßle J, Staffer S, Tuma-Kellner S, Khnykin D, Stremmel W, Merle U, Herrmann T, Chamulitrat W. Methionine- and Choline-Deficient Diet Enhances Adipose Lipolysis and Leptin Release in aP2-Cre Fatp4-Knockout Mice. Mol Nutr Food Res 2020; 64:e2000361. [PMID: 32991778 DOI: 10.1002/mnfr.202000361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/22/2020] [Indexed: 12/11/2022]
Abstract
SCOPE Inadequate intake of choline commonly leads to liver diseases. Methionine- and choline-deficient diets (MCDD) induce fatty liver in mice which is partly mediated by triglyceride (TG) lipolysis in white adipose tissues (WATs). Because Fatp4 knockdown has been shown to increase adipocyte lipolysis in vitro, here, the effects of MCDD on WAT lipolysis in aP2-Cre Fatp4-knockout (Fatp4A-/- ) mice are determined. METHODS AND RESULTS Isolated WATs of Fatp4A-/- mice exposed to MCD medium show an increase in lipolysis, and the strongest effect is noted on glycerol release from subcutaneous fat. Fatp4A-/- mice fed with MCDD for 4 weeks show an increase in serum glycerol, TG, and leptin levels associated with the activation of hormone-sensitive lipase in subcutaneous fat. Chow-fed Fatp4A-/- mice also show an increase in serum leptin and very-low-density lipoproteins as well as liver phosphatidylcholine and sphingomyelin levels. Both chow- and MCDD-fed Fatp4A-/- mice show a decrease in serum ketone and WAT sphingomyelin levels which supports a metabolic shift to TG for subsequent WAT lipolysis CONCLUSIONS: Adipose Fatp4 deficiency leads to TG lipolysis and leptin release, which are exaggerated by MCDD. The data imply hyperlipidemia risk by a low dietary choline intake and gene mutations that increase adipose TG levels.
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Affiliation(s)
- Yuting Cheng
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Hongying Gan-Schreier
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Jessica Seeßle
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Simone Staffer
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Sabine Tuma-Kellner
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Denis Khnykin
- Department of Pathology and Center for Immune Regulation, Rikshospitalet University Hospital, 0424, Oslo, Norway
| | - Wolfgang Stremmel
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Uta Merle
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
| | - Thomas Herrmann
- Westkuesten Hospital, Esmarchstraße 50, 25746, Heide, Germany
| | - Walee Chamulitrat
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
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15
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Yak FOXO1 and FOXO3 SNPs and association with production traits, and their promotes cells apoptosis via RNAi. Gene 2020; 743:144592. [PMID: 32198125 DOI: 10.1016/j.gene.2020.144592] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
FOXOs transcription factors not only play key roles in glucose metabolism, muscle atrophy and energy homeostasis but also play crucial transcriptional regulatory roles in the cell's metabolism, orchestrating programs of gene expression that regulate cell apoptosis, cell-cycle progression and oxidative stress resistance. However, the specific function of FOXOs promoting fibroblasts proliferation and apoptosis are still unknown. Thus, we used the High-Resolution Melting (HRM) and RNA interference methods to detect SNPs and function. We found one SNP in the exon of FOXO1, three SNPs were identified in the exon of FOXO3, and three SNPs and production traits were significantly different. The siRNA sequence of yak FOXO1 and FOXO3 were transfected into the yak fibroblasts, and effects were detected by a series of assays to reveal the function in yak fibroblasts. The results demonstrated that down-regulated expression of FOXO1 and FOXO3 resulted in up-regulated the expression of BAX, Caspase9 and Caspase3, and down-regulated the expression level of anti-apoptotic gene of BCL2. The apoptotic situation was consistent with results of the flow cytometry and Tunel test cell cycle and cell vitality results revealed that knockdown FOXO1 and FOXO3 resulted in increased P27 expression level and decreased CyclinD1. Meanwhile, cell vitality was also decreased. These results demonstrated that FOXO1 and FOXO3 are two novel regulatory factors to suppress cells proliferation and promote cells apoptosis. Furthermore, these results provide evidence that FOXO1 and FOXO3 play a functional role in cell apoptosis.
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16
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Wang Q, Zhang Q, Wang X, Zhang Y, Zhao X. WITHDRAWN: Yak FOXO1 and FOXO3 SNPs and association with production traits, and their promotes cells apoptosis via RNAi. Gene X 2020. [DOI: 10.1016/j.gene.2020.100029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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17
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Hofer DC, Zirkovits G, Pelzmann HJ, Huber K, Pessentheiner AR, Xia W, Uno K, Miyazaki T, Kon K, Tsuneki H, Pendl T, Al Zoughbi W, Madreiter-Sokolowski CT, Trausinger G, Abdellatif M, Schoiswohl G, Schreiber R, Eisenberg T, Magnes C, Sedej S, Eckhardt M, Sasahara M, Sasaoka T, Nitta A, Hoefler G, Graier WF, Kratky D, Auwerx J, Bogner-Strauss JG. N-acetylaspartate availability is essential for juvenile survival on fat-free diet and determines metabolic health. FASEB J 2019; 33:13808-13824. [PMID: 31638418 PMCID: PMC6894082 DOI: 10.1096/fj.201801323r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/10/2019] [Indexed: 12/15/2022]
Abstract
N-acetylaspartate (NAA) is synthesized by aspartate N-acetyltransferase (gene: Nat8l) from acetyl-coenzyme A and aspartate. In the brain, NAA is considered an important energy metabolite for lipid synthesis. However, the role of NAA in peripheral tissues remained elusive. Therefore, we characterized the metabolic phenotype of knockout (ko) and adipose tissue-specific (ako) Nat8l-ko mice as well as NAA-supplemented mice on various diets. We identified an important role of NAA availability in the brain during adolescence, as 75% of Nat8l-ko mice died on fat-free diet (FFD) after weaning but could be rescued by NAA supplementation. In adult life, NAA deficiency promotes a beneficial metabolic phenotype, as Nat8l-ko and Nat8l-ako mice showed reduced body weight, increased energy expenditure, and improved glucose tolerance on chow, high-fat, and FFDs. Furthermore, Nat8l-deficient adipocytes exhibited increased mitochondrial respiration, ATP synthesis, and an induction of browning. Conversely, NAA-treated wild-type mice showed reduced adipocyte respiration and lipolysis and increased de novo lipogenesis, culminating in reduced energy expenditure, glucose tolerance, and insulin sensitivity. Mechanistically, our data point to a possible role of NAA as modulator of pancreatic insulin secretion and suggest NAA as a critical energy metabolite for adipocyte and whole-body energy homeostasis.-Hofer, D. C., Zirkovits, G., Pelzmann, H. J., Huber, K., Pessentheiner, A. R., Xia, W., Uno, K., Miyazaki, T., Kon, K., Tsuneki, H., Pendl, T., Al Zoughbi, W., Madreiter-Sokolowski, C. T., Trausinger, G., Abdellatif, M., Schoiswohl, G., Schreiber, R., Eisenberg, T., Magnes, C., Sedej, S., Eckhardt, M., Sasahara, M., Sasaoka, T., Nitta, A., Hoefler, G., Graier, W. F., Kratky, D., Auwerx, J., Bogner-Strauss, J. G. N-acetylaspartate availability is essential for juvenile survival on fat-free diet and determines metabolic health.
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Affiliation(s)
- Dina C. Hofer
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Gabriel Zirkovits
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Helmut J. Pelzmann
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Fresenius Kabi Austria GmbH, Graz, Austria
| | - Katharina Huber
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ariane R. Pessentheiner
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Department of Medicine, University of California–San Diego, La Jolla, California, USA
| | - Wenmin Xia
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Kyosuke Uno
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Toh Miyazaki
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Kanta Kon
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Hiroshi Tsuneki
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Tobias Pendl
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Wael Al Zoughbi
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | | | - Gert Trausinger
- Joanneum Research, HEALTH–Institute for Biomedicine and Health Sciences, Graz, Austria
| | | | | | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Christoph Magnes
- Joanneum Research, HEALTH–Institute for Biomedicine and Health Sciences, Graz, Austria
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, University of Bonn, Bonn, Germany
| | | | - Toshiyasu Sasaoka
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Atsumi Nitta
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Gerald Hoefler
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Wolfgang F. Graier
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Juliane G. Bogner-Strauss
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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18
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Assessment of the Main Compounds of the Lipolytic System in Treadmill Running Rats: Different Response Patterns between the Right and Left Ventricle. Int J Mol Sci 2019; 20:ijms20102556. [PMID: 31137663 PMCID: PMC6566686 DOI: 10.3390/ijms20102556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/09/2019] [Accepted: 05/22/2019] [Indexed: 12/22/2022] Open
Abstract
The aim of the present study was to investigate the time and intensity dependent effects of exercise on the heart components of the lipolytic complex. Wistar rats ran on a treadmill with the speed of 18 m/min for 30 min (M30) or 120 min (M120) or with the speed of 28 m/min for 30 min (F30). The mRNA and protein expressions of the compounds adipose triglyceride lipase (ATGL), comparative gene identification-58 (CGI-58), G0/G1 switch gene 2 (G0S2), hormone sensitive lipase (HSL) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) were examined by real-time PCR and Western blot, respectively. Lipid content of free fatty acids (FFA), diacylglycerols (DG) and triacylglycerols (TG) were estimated by gas liquid chromatography. We observed virtually no changes in the left ventricle lipid contents and only minor fluctuations in its ATGL mRNA levels. This was in contrast with its right counterpart i.e., the content of TG and DG decreased in response to both increased duration and intensity of a run. This occurred in tandem with increased mRNA expression for ATGL, CGI-58 and decreased expression of G0S2. It is concluded that exercise affects behavior of the components of the lipolytic system and the lipid content in the heart ventricles. However, changes observed in the left ventricle did not mirror those in the right one.
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19
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Yu B, Zhang M, Chen J, Wang L, Peng X, Zhang X, Wang H, Wang A, Zhao D, Pang D, OuYang H, Tang X. Abnormality of hepatic triglyceride metabolism in Apc Min/+ mice with colon cancer cachexia. Life Sci 2019; 227:201-211. [PMID: 31002917 DOI: 10.1016/j.lfs.2019.04.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/10/2019] [Accepted: 04/16/2019] [Indexed: 01/01/2023]
Abstract
AIMS Colorectal cancer syndrome has been one of the greatest concerns in the world. Although several epidemiological studies have shown that hepatic low lipoprotein lipase (LPL) mRNA expression may be associated with dyslipidemia and tumor progression, it is still not known whether the liver plays an essential role in hyperlipidemia of ApcMin/+ mice. MAIN METHODS We measured the expression of metabolic enzymes that involved fatty acid uptake, de novo lipogenesis (DNL), β-oxidation and investigated hepatic triglyceride production in the liver of wild-type and ApcMin/+ mice. KEY FINDINGS We found that hepatic fatty acid uptake and DNL decreased, but there was no significant difference in fatty acid β-oxidation. Interestingly, the production of hepatic very low-density lipoprotein-triglyceride (VLDL-TG) decreased at 20 weeks of age, but marked steatosis was observed in the livers of the ApcMin/+ mouse. To further explore hypertriglyceridemia, we assessed the function of hepatic glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) for the first time. GPIHBP1 is governed by the transcription factor octamer-binding transcription factor-1 (Oct-1) which are involved in the nuclear factor-κB (NF-κB) signaling pathway in the liver of ApcMin/+ mice. Importantly, it was also confirmed that sn50 (100 μg/mL, an inhibitor of the NF-κB) reversed the tumor necrosis factor α (TNFα)-induced Oct-1 and GPIHBP1 reduction in HepG2 cells. SIGNIFICANCE Altogether, these findings highlighted a novel role of GPIHBP1 that might be responsible for hypertriglyceridemia in ApcMin/+ mice. Hypertriglyceridemia in these mice may be associated with their hepatic lipid metabolism development.
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Affiliation(s)
- Biao Yu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Mingjun Zhang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Jiahuan Chen
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Lingyu Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Xiaohuan Peng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Xinwei Zhang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - He Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Anbei Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Dazhong Zhao
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Daxin Pang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Hongsheng OuYang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China
| | - Xiaochun Tang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, No.5333 Xi'an Road, Lvyuan District, Changchun 130062, Jilin Province, China.
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20
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Hellmuth C, Kirchberg FF, Brandt S, Moß A, Walter V, Rothenbacher D, Brenner H, Grote V, Gruszfeld D, Socha P, Closa-Monasterolo R, Escribano J, Luque V, Verduci E, Mariani B, Langhendries JP, Poncelet P, Heinrich J, Lehmann I, Standl M, Uhl O, Koletzko B, Thiering E, Wabitsch M. An individual participant data meta-analysis on metabolomics profiles for obesity and insulin resistance in European children. Sci Rep 2019; 9:5053. [PMID: 30911015 PMCID: PMC6433919 DOI: 10.1038/s41598-019-41449-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 02/27/2019] [Indexed: 01/17/2023] Open
Abstract
Childhood obesity prevalence is rising in countries worldwide. A variety of etiologic factors contribute to childhood obesity but little is known about underlying biochemical mechanisms. We performed an individual participant meta-analysis including 1,020 pre-pubertal children from three European studies and investigated the associations of 285 metabolites measured by LC/MS-MS with BMI z-score, height, weight, HOMA, and lipoprotein concentrations. Seventeen metabolites were significantly associated with BMI z-score. Sphingomyelin (SM) 32:2 showed the strongest association with BMI z-score (P = 4.68 × 10−23) and was also closely related to weight, and less strongly to height and LDL, but not to HOMA. Mass spectrometric analyses identified SM 32:2 as myristic acid containing SM d18:2/14:0. Thirty-five metabolites were significantly associated to HOMA index. Alanine showed the strongest positive association with HOMA (P = 9.77 × 10−16), while acylcarnitines and non-esterified fatty acids were negatively associated with HOMA. SM d18:2/14:0 is a powerful marker for molecular changes in childhood obesity. Tracing back the origin of SM 32:2 to dietary source in combination with genetic predisposition will path the way for early intervention programs. Metabolic profiling might facilitate risk prediction and personalized interventions in overweight children.
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Affiliation(s)
- Christian Hellmuth
- LMU - Ludwig-Maximilians-Universität München, Dr. von Hauner Children's Hospital, Div. Metabolic and Nutritional Medicine, 80336, Munich, Germany
| | - Franca F Kirchberg
- LMU - Ludwig-Maximilians-Universität München, Dr. von Hauner Children's Hospital, Div. Metabolic and Nutritional Medicine, 80336, Munich, Germany
| | - Stephanie Brandt
- Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, University of Ulm, 89081, Ulm, Germany
| | - Anja Moß
- Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, University of Ulm, 89081, Ulm, Germany
| | - Viola Walter
- Division of Clinical Epidemiology and Aging Research, German Cancer Reasearch Center (DKFZ), 69120, Heidelberg, Germany
| | | | - Hermann Brenner
- Division of Clinical Epidemiology and Aging Research, German Cancer Reasearch Center (DKFZ), 69120, Heidelberg, Germany
| | - Veit Grote
- LMU - Ludwig-Maximilians-Universität München, Dr. von Hauner Children's Hospital, Div. Metabolic and Nutritional Medicine, 80336, Munich, Germany
| | - Dariusz Gruszfeld
- Neonatal Intensive Care Unit, Children's Memorial Health Institute, 04-736, Warsaw, Poland
| | - Piotr Socha
- Neonatal Intensive Care Unit, Children's Memorial Health Institute, 04-736, Warsaw, Poland
| | - Ricardo Closa-Monasterolo
- Pediatric Nutrition and Development Research Unit, Universitat Rovira I Virgili, IISPV, 43201, Reus, Spain
| | - Joaquin Escribano
- Pediatric Nutrition and Development Research Unit, Universitat Rovira I Virgili, IISPV, 43201, Reus, Spain
| | - Veronica Luque
- Pediatric Nutrition and Development Research Unit, Universitat Rovira I Virgili, IISPV, 43201, Reus, Spain
| | - Elvira Verduci
- Department of Paediatrics, San Paolo Hospital, University of Milan, 20142, Milano, Italy
| | - Benedetta Mariani
- Department of Paediatrics, San Paolo Hospital, University of Milan, 20142, Milano, Italy
| | | | - Pascale Poncelet
- Hôpital Universitaire des enfants Reine Fabila, 1020, Bruxelles, Belgium
| | - Joachim Heinrich
- Institute of Epidemiology I, Helmholtz Zentrum München- German Research Center for Environmental Health, 85764, Neuherberg, Germany.,Ludwig-Maximilians-Universität München, Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, 80336, Munich, Germany
| | - Irina Lehmann
- Department of Environmental Immunology/Core Facility Studies, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany.,Berlin Institute of Health and Charité- Universitätsmedizin Berlin, Molecular Epidemiology Unit, Berlin, Germany
| | - Marie Standl
- Institute of Epidemiology I, Helmholtz Zentrum München- German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Olaf Uhl
- LMU - Ludwig-Maximilians-Universität München, Dr. von Hauner Children's Hospital, Div. Metabolic and Nutritional Medicine, 80336, Munich, Germany
| | - Berthold Koletzko
- LMU - Ludwig-Maximilians-Universität München, Dr. von Hauner Children's Hospital, Div. Metabolic and Nutritional Medicine, 80336, Munich, Germany.
| | - Elisabeth Thiering
- LMU - Ludwig-Maximilians-Universität München, Dr. von Hauner Children's Hospital, Div. Metabolic and Nutritional Medicine, 80336, Munich, Germany.,Institute of Epidemiology I, Helmholtz Zentrum München- German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Martin Wabitsch
- Division of Pediatric Endocrinology and Diabetes, Interdisciplinary Obesity Unit, Department of Pediatrics and Adolescent Medicine, University of Ulm, 89081, Ulm, Germany
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21
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Bartels ED, Guo S, Kousholt BS, Larsen JR, Hasenkam JM, Burnett J, Nielsen LB, Ashina M, Goetze JP. High doses of ANP and BNP exacerbate lipolysis in humans and the lipolytic effect of BNP is associated with cardiac triglyceride content in pigs. Peptides 2019; 112:43-47. [PMID: 30508635 DOI: 10.1016/j.peptides.2018.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/13/2022]
Abstract
Drugs facilitating the cardioprotective effects of natriuretic peptides are introduced in heart failure treatment. ANP and BNP also stimulate lipolysis and increase circulating concentrations of free fatty acids (FFAs); an aspect, however, thought to be confined to primates. We examined the lipolytic effect of natriuretic peptide infusion in healthy young men and evaluated the effect in a porcine model of myocardial ischemia and reperfusion. Six young healthy normotensive men underwent infusion with ANP, BNP, or CNP for 20 min. Blood samples were collected before, during, and after infusion for measurement of FFAs. In a porcine model of myocardial ischemia and reperfusion, animals were infused for 3 h with either BNP (n = 7) or saline (n = 5). Blood samples were collected throughout the infusion period, and cardiac tissue was obtained after infusion for lipid analysis. In humans, ANP infusion dose-dependently increased the FFA concentration in plasma 2.5-10-fold (baseline vs. 0.05 μg/kg/min P < 0.002) and with BNP 1.6-3.5-fold (P = 0.001, baseline vs. 0.02 μg/kg/min) 30 min after initiation of infusion. Infusion of CNP did not affect plasma FFA. In pigs, BNP infusion induced a 3.5-fold increase in plasma FFA (P < 0.0001), which remained elevated throughout the infusion period. Triglyceride content in porcine right cardiac ventricle tissue increased ∼5.5 fold in animals infused with BNP (P = 0.02). Natriuretic peptide infusion has similar lipolytic activity in human and pig. Our data suggest that short-term infusion increases the cardiac lipid content, and that the pig is a suitable model for studies of long-term effects mediated by natriuretic peptides.
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Affiliation(s)
- Emil D Bartels
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
| | - Song Guo
- Department of Neurology and Danish Headache Center, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte S Kousholt
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Jens R Larsen
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - J Michael Hasenkam
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - John Burnett
- Department of Cardiorenal physiology (Mayo Clinic, Rochester, MN, USA
| | - Lars B Nielsen
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Copenhagen University, Denmark; Aarhus University, Denmark
| | - Messoud Ashina
- Department of Neurology and Danish Headache Center, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Copenhagen University, Denmark
| | - Jens P Goetze
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Cardiorenal physiology (Mayo Clinic, Rochester, MN, USA; Copenhagen University, Denmark
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22
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Huang KT, Hsu LW, Chen KD, Kung CP, Goto S, Chen CL. Decreased PEDF Expression Promotes Adipogenic Differentiation through the Up-Regulation of CD36. Int J Mol Sci 2018; 19:ijms19123992. [PMID: 30544997 PMCID: PMC6321369 DOI: 10.3390/ijms19123992] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/05/2018] [Accepted: 12/07/2018] [Indexed: 01/10/2023] Open
Abstract
Adipogenesis is a tightly regulated cellular process that involves the action of multiple signaling pathways. Characterization of regulators that are associated with adipose development is crucial to understanding the mechanisms underlying obesity and other metabolic disorders. Pigment epithelium-derived factor (PEDF) is a secreted glycoprotein that was first described as a neurotrophic factor. The role of PEDF in lipid metabolism was established when adipose triglyceride lipase (ATGL), a major triglyceride hydrolase, was characterized as its binding partner. In this study, we investigated the downstream effects of PEDF on adipogenic differentiation using rat adipose-derived stem cells (AdSCs) and the mouse pre-adipocyte cell line 3T3-L1. Knocking down PEDF in differentiating cells resulted in elevated levels of ATGL and CD36, as well as other adipogenic markers, with a concomitant increase in adipocyte number. CD36, a scavenger receptor for a variety of ligands, regulated proliferation and lipogenic gene expression during adipogenesis. The CD36 increase due to PEDF down-regulation might be a result of elevated PPARγ. We further demonstrated that PEDF expression was regulated by dexamethasone, a synthetic glucocorticoid that is widely used for adipogenesis at the transcriptional level. Taken together, our findings highlight that PEDF negatively regulates adipogenesis through the regulation of various signaling intermediates, and it may play a crucial role in lipid metabolic disorders.
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Affiliation(s)
- Kuang-Tzu Huang
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
- Liver Transplantation Center, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
| | - Li-Wen Hsu
- Liver Transplantation Center, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
| | - Kuang-Den Chen
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
- Liver Transplantation Center, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
| | - Chao-Pin Kung
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
- Liver Transplantation Center, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
| | - Shigeru Goto
- Fukuoka Institute of Occupational Health, Fukuoka 815-0081, Japan.
| | - Chao-Long Chen
- Liver Transplantation Center, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 83301, Taiwan.
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23
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Hu CJ, Jiang QY, Zhang T, Yin YL, Li FN, Su JY, Wu GY, Kong XF. Dietary supplementation with arginine and glutamic acid enhances key lipogenic gene expression in growing pigs. J Anim Sci 2018; 95:5507-5515. [PMID: 29293787 DOI: 10.2527/jas2017.1703] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Our previous study showed dietary supplementation with Arg and Glu increased intramuscular fat deposition and decreased back fat thickness in pigs, suggesting that the genes involved in lipid metabolism might be regulated differently in muscle and s.c. adipose (SA) tissues. Sixty Duroc × Large White × Landrace pigs with an average initial BW of 77.1 ± 1.3 kg were randomly assigned to 1 of 5 treatment groups (castrated male to female ratio = 1:1). Pigs in the control group were fed a basic diet, and those in experimental groups were fed the basic diet supplemented with 2.05% alanine (isonitrogenous group), 1.00% arginine (Arg group), 1.00% glutamic acid + 1.44% alanine (Glu group), or 1.00% arginine + 1.00% glutamic acid (Arg+Glu group). Fatty acid percentages and mRNA expression levels of the genes involved in lipid metabolism in muscle and SA tissues were examined. The percentages of C14:0 and C16:0 in the SA tissue of Glu group pigs and C14:0 in the longissimus dorsi (LD) muscle of Glu and Arg+Glu groups decreased ( < 0.05) compared to the basic diet group. The Arg+Glu group showed the highest ( < 0.05) hormone-sensitive lipase expression level in SA tissue and higher ( < 0.05) mRNA levels of in the LD muscle than the basic diet and isonitrogenous groups. Additionally, the mRNA level of fatty acid synthase in the Arg+Glu group was more upregulated ( < 0.05) than that of the Arg group. An increase in the mRNA level of in the biceps femoris muscle was also observed in the Arg+Glu group ( < 0.05) compared with the basic diet and isonitrogenous groups. Collectively, these findings suggest that dietary supplementation with Arg and Glu upregulates the expression of genes involved in adipogenesis in muscle tissues and lipolysis in SA tissues.
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24
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Page MM, Skovsø S, Cen H, Chiu AP, Dionne DA, Hutchinson DF, Lim GE, Szabat M, Flibotte S, Sinha S, Nislow C, Rodrigues B, Johnson JD. Reducing insulin via conditional partial gene ablation in adults reverses diet-induced weight gain. FASEB J 2018; 32:1196-1206. [PMID: 29122848 PMCID: PMC5892722 DOI: 10.1096/fj.201700518r] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Excess circulating insulin is associated with obesity in humans and in animal models. However, the physiologic causality of hyperinsulinemia in adult obesity has rightfully been questioned because of the absence of clear evidence that weight loss can be induced by acutely reversing diet-induced hyperinsulinemia. Herein, we describe the consequences of inducible, partial insulin gene deletion in a mouse model in which animals have already been made obese by consuming a high-fat diet. A modest reduction in insulin production/secretion was sufficient to cause significant weight loss within 5 wk, with a specific effect on visceral adipose tissue. This result was associated with a reduction in the protein abundance of the lipodystrophy gene polymerase I and transcript release factor ( Ptrf; Cavin) in gonadal adipose tissue. RNAseq analysis showed that reduced insulin and weight loss also associated with a signature of reduced innate immunity. This study demonstrates that changes in circulating insulin that are too fine to adversely affect glucose homeostasis nonetheless exert control over adiposity.-Page, M. M., Skovsø, S., Cen, H., Chiu, A. P., Dionne, D. A., Hutchinson, D. F., Lim, G. E., Szabat, M., Flibotte, S., Sinha, S., Nislow, C., Rodrigues, B., Johnson, J. D. Reducing insulin via conditional partial gene ablation in adults reverses diet-induced weight gain.
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Affiliation(s)
- Melissa M Page
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Søs Skovsø
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Haoning Cen
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amy P Chiu
- Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Derek A Dionne
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Daria F Hutchinson
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gareth E Lim
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marta Szabat
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stephane Flibotte
- Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sunita Sinha
- Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Corey Nislow
- Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian Rodrigues
- Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - James D Johnson
- Department of Cellular and Physiological Sciences, Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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25
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Lewis JE, Samms RJ, Cooper S, Luckett JC, Perkins AC, Adams AC, Tsintzas K, Ebling FJP. Reduced adiposity attenuates FGF21 mediated metabolic improvements in the Siberian hamster. Sci Rep 2017; 7:4238. [PMID: 28652585 PMCID: PMC5484705 DOI: 10.1038/s41598-017-03607-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/05/2017] [Indexed: 11/26/2022] Open
Abstract
FGF21 exerts profound metabolic effects in Siberian hamsters exposed to long day (LD) photoperiods that increase appetite and adiposity, however these effects are attenuated in short day (SD) animals that display hypophagia and reduced adiposity. The aim of this study was to investigate whether the beneficial effects of a novel mimetic of FGF21 in the LD state are a consequence of increased adiposity or of the central photoperiodic state. This was achieved by investigating effects of FGF21 in aged hamsters, which is associated with reduced adiposity. In LD hamsters with increased adiposity, FGF21 lowered body weight as a result of both reduced daily food intake and increased caloric expenditure, driven by an increase in whole-body fat oxidation. However, in LD animals with reduced adiposity, the effect of FGF21 on body weight, caloric intake and fat oxidation were significantly attenuated or absent when compared to those with increased adiposity. These attenuated/absent effects were underpinned by the inability of FGF21 to increase the expression of key thermogenic genes in interscapular and visceral WAT. Our study demonstrates the efficacy of a novel FGF21 mimetic in hamsters, but reveals attenuated effects in the animal model where adiposity is reduced naturally independent of photoperiod.
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Affiliation(s)
- Jo E Lewis
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
| | | | - Scott Cooper
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Jeni C Luckett
- Radiological Sciences, School of Medicine, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Alan C Perkins
- Radiological Sciences, School of Medicine, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Andrew C Adams
- Lilly Research Laboratories, Indianapolis, IN, 46285, USA
| | - Kostas Tsintzas
- MRC/ARUK Centre for Musculoskeletal Ageing, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Francis J P Ebling
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
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26
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Takanashi M, Taira Y, Okazaki S, Takase S, Kimura T, Li CC, Xu PF, Noda A, Sakata I, Kumagai H, Ikeda Y, Iizuka Y, Yahagi N, Shimano H, Osuga JI, Ishibashi S, Kadowaki T, Okazaki H. Role of Hormone-sensitive Lipase in Leptin-Promoted Fat Loss and Glucose Lowering. J Atheroscler Thromb 2017; 24:1105-1116. [PMID: 28413180 PMCID: PMC5684476 DOI: 10.5551/jat.39552] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Aim: Myriad biological effects of leptin may lead to broad therapeutic applications for various metabolic diseases, including diabetes and its complications; however, in contrast to its anorexic effect, the molecular mechanisms underlying adipopenic and glucose-lowering effects of leptin have not been fully understood. Here we aim to clarify the role of hormone-sensitive lipase (HSL) in leptin's action. Methods: Wild-type (WT) and HSL-deficient (HSLKO) mice were made hyperleptinemic by two commonly-used methods: adenovirus-mediated overexpression of leptin and continuous subcutaneous infusion of leptin by osmotic pumps. The amount of food intake, body weights, organ weights, and parameters of glucose and lipid metabolism were measured. Results: Hyperleptinemia equally suppressed the food intake in WT and HSLKO mice. On the other hand, leptin-mediated fat loss and glucose-lowering were significantly blunted in the absence of HSL when leptin was overexpressed by recombinant adenovirus carrying leptin. By osmotic pumps, the fat-losing and glucose-lowering effects of leptin were milder due to lower levels of hyperleptinemia; although the difference between WT and HSLKO mice did not reach statistical significance, HSLKO mice had a tendency to retain more fat than WT mice in the face of hyperleptinemia. Conclusions: We clarify for the first time the role of HSL in leptin's effect using a genetic model: leptin-promoted fat loss and glucose-lowering are at least in part mediated via HSL-mediated lipolysis. Further studies to define the pathophysiological role of adipocyte lipases in leptin action may lead to a new therapeutic approach to circumvent leptin resistance.
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Affiliation(s)
- Mikio Takanashi
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Yoshino Taira
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Sachiko Okazaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Satoru Takase
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Takeshi Kimura
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Cheng Cheng Li
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Peng Fei Xu
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Akari Noda
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University
| | - Hidetoshi Kumagai
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Yuichi Ikeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Yoko Iizuka
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Naoya Yahagi
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Hitoshi Shimano
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Jun-Ichi Osuga
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University
| | - Takashi Kadowaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Hiroaki Okazaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
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27
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Casado ME, Pastor O, García-Seisdedos D, Huerta L, Kraemer FB, Lasunción MA, Martín-Hidalgo A, Busto R. Hormone-sensitive lipase deficiency disturbs lipid composition of plasma membrane microdomains from mouse testis. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1142-1150. [DOI: 10.1016/j.bbalip.2016.06.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/01/2016] [Accepted: 06/24/2016] [Indexed: 11/17/2022]
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28
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AMPK Phosphorylates Desnutrin/ATGL and Hormone-Sensitive Lipase To Regulate Lipolysis and Fatty Acid Oxidation within Adipose Tissue. Mol Cell Biol 2016; 36:1961-76. [PMID: 27185873 DOI: 10.1128/mcb.00244-16] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/06/2016] [Indexed: 01/10/2023] Open
Abstract
The role of AMP-activated protein kinase (AMPK) in promoting fatty acid (FA) oxidation in various tissues, such as liver and muscle, has been well understood. However, the role of AMPK in lipolysis and FA metabolism in adipose tissue has been controversial. To investigate the role of AMPK in the regulation of adipose lipolysis in vivo, we generated mice with adipose-tissue-specific knockout of both the α1 and α2 catalytic subunits of AMPK (AMPK-ASKO mice) by using aP2-Cre and adiponectin-Cre. Both models of AMPK-ASKO ablation show no changes in desnutrin/ATGL levels but have defective phosphorylation of desnutrin/ATGL at S406 to decrease its triacylglycerol (TAG) hydrolase activity, lowering basal lipolysis in adipose tissue. These mice also show defective phosphorylation of hormone-sensitive lipase (HSL) at S565, with higher phosphorylation at protein kinase A sites S563 and S660, increasing its hydrolase activity and isoproterenol-stimulated lipolysis. With higher overall adipose lipolysis, both models of AMPK-ASKO mice are lean, having smaller adipocytes with lower TAG and higher intracellular free-FA levels. Moreover, FAs from higher lipolysis activate peroxisome proliferator-activated receptor delta to induce FA oxidative genes and increase FA oxidation and energy expenditure. Overall, for the first time, we provide in vivo evidence of the role of AMPK in the phosphorylation and regulation of desnutrin/ATGL and HSL and thus adipose lipolysis.
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29
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Das SK, Stadelmeyer E, Schauer S, Schwarz A, Strohmaier H, Claudel T, Zechner R, Hoefler G, Vesely PW. Micro RNA-124a regulates lipolysis via adipose triglyceride lipase and comparative gene identification 58. Int J Mol Sci 2015; 16:8555-68. [PMID: 25894224 PMCID: PMC4425096 DOI: 10.3390/ijms16048555] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 01/14/2023] Open
Abstract
Lipolysis is the biochemical pathway responsible for the catabolism of cellular triacylglycerol (TG). Lipolytic TG breakdown is a central metabolic process leading to the generation of free fatty acids (FA) and glycerol, thereby regulating lipid, as well as energy homeostasis. The precise tuning of lipolysis is imperative to prevent lipotoxicity, obesity, diabetes and other related metabolic disorders. Here, we present our finding that miR-124a attenuates RNA and protein expression of the major TG hydrolase, adipose triglyceride lipase (ATGL/PNPLA2) and its co-activator comparative gene identification 58 (CGI-58/ABHD5). Ectopic expression of miR-124a in adipocytes leads to reduced lipolysis and increased cellular TG accumulation. This phenotype, however, can be rescued by overexpression of truncated Atgl lacking its 3'UTR, which harbors the identified miR-124a target site. In addition, we observe a strong negative correlation between miR-124a and Atgl expression in various murine tissues. Moreover, miR-124a regulates the expression of Atgl and Cgi-58 in murine white adipose tissue during fasting as well as the expression of Atgl in murine liver, during fasting and re-feeding. Together, these results point to an instrumental role of miR-124a in the regulation of TG catabolism. Therefore, we suggest that miR-124a may be involved in the regulation of several cellular and organismal metabolic parameters, including lipid storage and plasma FA concentration.
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Affiliation(s)
- Suman K Das
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria.
| | - Elke Stadelmeyer
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria.
| | - Silvia Schauer
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria.
| | - Anna Schwarz
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria.
| | - Heimo Strohmaier
- Center for Medical Research, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria.
| | - Thiery Claudel
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
| | - Rudolf Zechner
- Institute of Molecular Biosciences, Karl Franzens University of Graz, Heinrichstraße 31, 8010 Graz, Austria.
| | - Gerald Hoefler
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria.
| | - Paul W Vesely
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria.
- Institute of Molecular Biosciences, Karl Franzens University of Graz, Heinrichstraße 31, 8010 Graz, Austria.
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30
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Stelmanska E, Szrok S, Swierczynski J. Progesterone-induced down-regulation of hormone sensitive lipase (Lipe) and up-regulation of G0/G1 switch 2 (G0s2) genes expression in inguinal adipose tissue of female rats is reflected by diminished rate of lipolysis. J Steroid Biochem Mol Biol 2015; 147:31-9. [PMID: 25448749 DOI: 10.1016/j.jsbmb.2014.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 11/17/2014] [Accepted: 11/18/2014] [Indexed: 11/23/2022]
Abstract
Decreased lipolytic activity in adipose tissue may be one of the reasons behind excess accumulation of body fat during pregnancy. The aim of this study was to analyze the effect of progesterone on the expression of: (a) Lipe (encoding hormone-sensitive lipase, HSL), (b) Pnpla2 (encoding adipose triglyceride lipase, ATGL), (c) abhydrolase domain containing 5 (Abhd5), and (d) G0/G1 switch 2 (G0s2) genes in white adipose tissue (WAT), as potential targets for progesterone action during the course of pregnancy. Administration of progesterone to female rats, which was reflected by approximately 2.5-fold increase in circulating progesterone concentration, is associated with a decrease in Lipe gene expression in the inguinal WAT. The expression of Pnpla2 gene in all main fat depots of females and males remained unchanged after progesterone administration. Administration of progesterone resulted in an increase in the expression of Abhd5 gene (whose product increases ATGL activity) and G0s2 gene (whose product decreases ATGL activity) in the inguinal WAT of female rats. Mifepristone, a selective antagonist of progesterone receptor, abolished the effect of progesterone on Lipe, Abhd5 and G0s2 genes expression in the inguinal WAT. The decrease in Lipe and the increase in Abhd5 and G0s2 genes expression was associated with lower rate of stimulated lipolysis. Administration of progesterone exerted no effect on Lipe, Abhd5 and G0s2 genes expression and stimulated lipolysis in the retroperitoneal WAT of females, as well as in the inguinal, epididymal and retroperitoneal WAT of males. In conclusion, our findings suggest that progesterone decreases the rate of lipolysis in the inguinal WAT of female rats, inhibiting the activity of both ATGL (by stimulating synthesis of G0S2 - specific inhibitor of the enzyme) and HSL (due to inhibition of Lipe gene expression).
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Affiliation(s)
- Ewa Stelmanska
- Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland
| | - Sylwia Szrok
- Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland
| | - Julian Swierczynski
- Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland.
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31
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Differential expression of lipid metabolism-related genes and myosin heavy chain isoform genes in pig muscle tissue leading to different meat quality. Animal 2015; 9:1073-80. [PMID: 25716066 DOI: 10.1017/s1751731115000324] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The aim of this study was to investigate the variations in meat quality, lipid metabolism-related genes, myosin heavy chain (MyHC) isoform genes and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) gene mRNA expressions in longissimus dorsi muscle (LM) of two different pig breeds. Six Rongchang and six Landrace barrows were slaughtered at 161 days of age. Subsequently, meat quality traits and gene expression levels in LM were observed. Results showed that Rongchang pigs not only exhibited greater pH, CIE a*24 h and intramuscular fat content but also exhibited lower body weight, carcass weight, dressing percentage, LM area and CIE b*24 h compared with Landrace pigs (P<0.05). Meanwhile, the mRNA expression levels of the lipogenesis (peroxisome proliferator-activated receptor gamma, acetyl-CoA carboxylase and fatty acid synthase) and fatty acid uptake (lipoprotein lipase)-related genes were greater in the Rongchang (P<0.05), whereas the lipolysis (adipose triglyceride lipase and hormone sensitive lipase) and fatty acid oxidation (carnitine palmitoyltransferase-1B)-related genes were better expressed in the Landrace. Moreover, compared with the Landrace, the mRNA expression levels of MyHCI, MyHCIIa and MyHCIIx were greater, whereas the mRNA expression levels of MyHCIIb were lower in the Rongchang pigs (P<0.05). In addition, the mRNA expression levels of PGC-1α were greater in Rongchang pigs than in the Landrace (P<0.05), which can partly explain the differences in MyHC isoform gene expressions between Rongchang and Landrace pigs. Although the small number of samples does not allow to obtain a definitive conclusion, we can suggest that Rongchang pigs possess better meat quality, and the underlying molecular mechanisms responsible for the better meat quality in fatty pigs may be partly due to the higher mRNA expression levels of lipogenesis and fatty acid uptake-related genes, as well as the oxidative and intermediate muscle fibers, and due to the lower mRNA expression levels of lipolysis and fatty acid oxidation-related genes, as well as the glycolytic muscle fibers.
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Fatty acid signaling: the new function of intracellular lipases. Int J Mol Sci 2015; 16:3831-55. [PMID: 25674855 PMCID: PMC4346929 DOI: 10.3390/ijms16023831] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 11/19/2014] [Accepted: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
Until recently, intracellular triacylglycerols (TAG) stored in the form of cytoplasmic lipid droplets have been considered to be only passive “energy conserves”. Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed.
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Sam S, Mazzone T. Adipose tissue changes in obesity and the impact on metabolic function. Transl Res 2014; 164:284-92. [PMID: 24929206 DOI: 10.1016/j.trsl.2014.05.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 05/13/2014] [Accepted: 05/14/2014] [Indexed: 12/18/2022]
Abstract
Obesity is associated with adverse alterations in adipose tissue that predispose to metabolic dysregulation. These adverse alterations include accumulation of inflammatory macrophages leading to the activation of inflammation pathways, reduction in lipid turnover, and deposition of fat in ectopic locations. These alterations are precursors to the development of insulin resistance and metabolic dysfunction.
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Affiliation(s)
- Susan Sam
- Department of Medicine, Section of Endocrinology, Pritzker School of Medicine, University of Chicago, Chicago, Ill.
| | - Theodore Mazzone
- Department of Medicine, NorthShore University Health System, Pritzker School of Medicine, University of Chicago, Chicago, Ill
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Albert JS, Yerges-Armstrong LM, Horenstein RB, Pollin TI, Sreenivasan UT, Chai S, Blaner WS, Snitker S, O'Connell JR, Gong DW, Breyer RJ, Ryan AS, McLenithan JC, Shuldiner AR, Sztalryd C, Damcott CM. Null mutation in hormone-sensitive lipase gene and risk of type 2 diabetes. N Engl J Med 2014; 370:2307-2315. [PMID: 24848981 PMCID: PMC4096982 DOI: 10.1056/nejmoa1315496] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Lipolysis regulates energy homeostasis through the hydrolysis of intracellular triglycerides and the release of fatty acids for use as energy substrates or lipid mediators in cellular processes. Genes encoding proteins that regulate energy homeostasis through lipolysis are thus likely to play an important role in determining susceptibility to metabolic disorders. METHODS We sequenced 12 lipolytic-pathway genes in Old Order Amish participants whose fasting serum triglyceride levels were at the extremes of the distribution and identified a novel 19-bp frameshift deletion in exon 9 of LIPE, encoding hormone-sensitive lipase (HSL), a key enzyme for lipolysis. We genotyped the deletion in DNA from 2738 Amish participants and performed association analyses to determine the effects of the deletion on metabolic traits. We also obtained biopsy specimens of abdominal subcutaneous adipose tissue from 2 study participants who were homozygous for the deletion (DD genotype), 10 who were heterozygous (ID genotype), and 7 who were noncarriers (II genotype) for assessment of adipose histologic characteristics, lipolysis, enzyme activity, cytokine release, and messenger RNA (mRNA) and protein levels. RESULTS Carriers of the mutation had dyslipidemia, hepatic steatosis, systemic insulin resistance, and diabetes. In adipose tissue from study participants with the DD genotype, the mutation resulted in the absence of HSL protein, small adipocytes, impaired lipolysis, insulin resistance, and inflammation. Transcription factors responsive to peroxisome-proliferator-activated receptor γ (PPAR-γ) and downstream target genes were down-regulated in adipose tissue from participants with the DD genotype, altering the regulation of pathways influencing adipogenesis, insulin sensitivity, and lipid metabolism. CONCLUSIONS These findings indicate the physiological significance of HSL in adipocyte function and the regulation of systemic lipid and glucose homeostasis and underscore the severe metabolic consequences of impaired lipolysis. (Funded by the National Institutes of Health and others).
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Affiliation(s)
- Jessica S Albert
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Laura M Yerges-Armstrong
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Richard B Horenstein
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Toni I Pollin
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Urmila T Sreenivasan
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Sumbul Chai
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - William S Blaner
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Soren Snitker
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Jeffrey R O'Connell
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Da-Wei Gong
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Richard J Breyer
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Alice S Ryan
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - John C McLenithan
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Alan R Shuldiner
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Carole Sztalryd
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
| | - Coleen M Damcott
- Program for Personalized and Genomic Medicine and Department of Medicine, University of Maryland School of Medicine (J.S.A., L.M.Y.-A., R.B.H., T.I.P., U.T.S., S.C., S.S., J.R.O., D.-W.G., J.C.M., A.R.S., C.S., C.M.D.), and the Geriatrics Research and Education Clinical Center (D.-W.G., A.S.R., A.R.S., C.S.), Department of Radiology and Nuclear Medicine (R.J.B.), and the Veterans Affairs (VA) Research Service, Department of Medicine, Division of Gerontology and Geriatric Medicine (A.S.R.), Baltimore VA Medical Center - all in Baltimore; and the Department of Medicine, Columbia University, New York (W.S.B.)
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Abstract
In adipocytes the hydrolysis of TAG to produce fatty acids and glycerol under fasting conditions or times of elevated energy demands is tightly regulated by neuroendocrine signals, resulting in the activation of lipolytic enzymes. Among the classic regulators of lipolysis, adrenergic stimulation and the insulin-mediated control of lipid mobilisation are the best known. Initially, hormone-sensitive lipase (HSL) was thought to be the rate-limiting enzyme of the first lipolytic step, while we now know that adipocyte TAG lipase is the key enzyme for lipolysis initiation. Pivotal, previously unsuspected components have also been identified at the protective interface of the lipid droplet surface and in the signalling pathways that control lipolysis. Perilipin, comparative gene identification-58 (CGI-58) and other proteins of the lipid droplet surface are currently known to be key regulators of the lipolytic machinery, protecting or exposing the TAG core of the droplet to lipases. The neuroendocrine control of lipolysis is prototypically exerted by catecholaminergic stimulation and insulin-induced suppression, both of which affect cyclic AMP levels and hence the protein kinase A-mediated phosphorylation of HSL and perilipin. Interestingly, in recent decades adipose tissue has been shown to secrete a large number of adipokines, which exert direct effects on lipolysis, while adipocytes reportedly express a wide range of receptors for signals involved in lipid mobilisation. Recently recognised mediators of lipolysis include some adipokines, structural membrane proteins, atrial natriuretic peptides, AMP-activated protein kinase and mitogen-activated protein kinase. Lipolysis needs to be reanalysed from the broader perspective of its specific physiological or pathological context since basal or stimulated lipolytic rates occur under diverse conditions and by different mechanisms.
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Omega-3 phospholipids from fish suppress hepatic steatosis by integrated inhibition of biosynthetic pathways in dietary obese mice. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:267-78. [PMID: 24295779 DOI: 10.1016/j.bbalip.2013.11.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 11/14/2013] [Accepted: 11/21/2013] [Indexed: 12/25/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) accompanies obesity and insulin resistance. Recent meta-analysis suggested omega-3 polyunsaturated fatty acids DHA and EPA to decrease liver fat in NAFLD patients. Antiinflammatory, hypolipidemic, and insulin-sensitizing effects ofDHA/EPA depend on their lipid form, with marine phospholipids showing better efficacy than fish oils. We characterized the mechanisms underlying beneficial effects of DHA/EPA phospholipids, alone or combined with an antidiabetic drug, on hepatosteatosis. C57BL/6N mice were fed for 7 weeks an obesogenic high-fat diet (cHF) or cHF-based interventions: (i) cHF supplemented with phosphatidylcholine-rich concentrate from herring (replacing 10% of dietary lipids; PC), (ii) cHF containing rosiglitazone (10 mg/kg diet; R), or (iii) PC + R. Metabolic analyses, hepatic gene expression and lipidome profiling were performed. Results showed that PC and PC + R prevented cHlF-induced weight gain and glucose intolerance, while all interventions reduced abdominal fat and plasma triacylglycerols. PC and PC + R also lowered hepatic and plasma cholesterol and reduced hepatosteatosis. Microarray analysis revealed integrated downregulation of hepatic lipogenic and cholesterol biosynthesis pathways by PC, while R-induced lipogenesis was fully counteracted in PC + R Gene expression changes in PC and PC + R were associated with preferential enrichment of hepatic phosphatidylcholine and phosphatidylethanolamine fractions by DHA/EPA. The complex downregulation of hepatic lipogenic and cholesterol biosynthesis genes and the antisteatotic effects were unique to DHA/EPA-containing phospholipids, since they were absent in mice fed soy-derived phosphatidylcholine. Thus, inhibition of lipid and cholesterol biosynthesis associated with potent antisteatotic effects in the liver in response to DHA/EPA-containing phospholipids support their use in NAFLD prevention and treatment.
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Trent CM, Yu S, Hu Y, Skoller N, Huggins LA, Homma S, Goldberg IJ. Lipoprotein lipase activity is required for cardiac lipid droplet production. J Lipid Res 2014; 55:645-58. [PMID: 24493834 PMCID: PMC3966699 DOI: 10.1194/jlr.m043471] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rodent heart accumulates TGs and lipid droplets during fasting. The sources of heart lipids could be either FFAs liberated from adipose tissue or FAs from lipoprotein-associated TGs via the action of lipoprotein lipase (LpL). Because circulating levels of FFAs increase during fasting, it has been assumed that albumin transported FFAs are the source of lipids within heart lipid droplets. We studied mice with three genetic mutations: peroxisomal proliferator-activated receptor α deficiency, cluster of differentiation 36 (CD36) deficiency, and heart-specific LpL deletion. All three genetically altered groups of mice had defective accumulation of lipid droplet TGs. Moreover, hearts from mice treated with poloxamer 407, an inhibitor of lipoprotein TG lipolysis, also failed to accumulate TGs, despite increased uptake of FFAs. TG storage did not impair maximal cardiac function as measured by stress echocardiography. Thus, LpL hydrolysis of circulating lipoproteins is required for the accumulation of lipids in the heart of fasting mice.
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Affiliation(s)
- Chad M Trent
- Division of Preventive Medicine and Nutrition, Columbia University College of Physicians and Surgeons, New York, NY 10032
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Variation in the ovine hormone-sensitive lipase gene (HSL) and its association with growth and carcass traits in New Zealand Suffolk sheep. Mol Biol Rep 2014; 41:2463-9. [PMID: 24443229 DOI: 10.1007/s11033-014-3102-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Accepted: 01/06/2014] [Indexed: 10/25/2022]
Abstract
The hormone-sensitive lipase (HSL) plays an important role in the regulation of lipolysis in adipose tissues, by catalysing a rate-limiting step in triglyceride hydrolysis. Variation within the human HSL gene (HSL) has been associated with an increased risk of obesity. In this study, variation within three regions (exon 3-4, exon 5-6 and exon 9) of ovine HSL was investigated in 538 Suffolk lambs bred from 13 independent sires using PCR-SSCP. Four sequence variants of intron 5 (designated A-D) and two variants of exon 9 (designated a and b) of ovine HSL were detected. No variation was found in exon 3-4 of the gene. The associations of the variation within ovine HSL with post-weaning growth and carcass traits including eye muscle depth (EMD), eye muscle width (EMW) and fat depth above the eye muscle (FDM) were assessed in 262 of the above 538 lambs using general linear mixed-effects models. In the single variant models, the presence of intron 5 A in a lamb's genotype was associated with reduced EMD (P = 0.036) and EMW (P = 0.018), whereas the presence of intron 5 C was associated with increased EMD (P < 0.001), EMW (P < 0.001) and FDM (P = 0.017). The association of C with increased EMD (P = 0.002) and EMW (P = 0.002) persisted in the multi-variant model. No association between HSL intron 5 variants and post-weaning growth, or between HSL exon 9 variants, post-weaning growth or carcass traits, were found.
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Pessentheiner AR, Pelzmann HJ, Walenta E, Schweiger M, Groschner LN, Graier WF, Kolb D, Uno K, Miyazaki T, Nitta A, Rieder D, Prokesch A, Bogner-Strauss JG. NAT8L (N-acetyltransferase 8-like) accelerates lipid turnover and increases energy expenditure in brown adipocytes. J Biol Chem 2013; 288:36040-51. [PMID: 24155240 PMCID: PMC3861652 DOI: 10.1074/jbc.m113.491324] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
NAT8L (N-acetyltransferase 8-like) catalyzes the formation of N-acetylaspartate (NAA) from acetyl-CoA and aspartate. In the brain, NAA delivers the acetate moiety for synthesis of acetyl-CoA that is further used for fatty acid generation. However, its function in other tissues remained elusive. Here, we show for the first time that Nat8l is highly expressed in adipose tissues and murine and human adipogenic cell lines and is localized in the mitochondria of brown adipocytes. Stable overexpression of Nat8l in immortalized brown adipogenic cells strongly increases glucose incorporation into neutral lipids, accompanied by increased lipolysis, indicating an accelerated lipid turnover. Additionally, mitochondrial mass and number as well as oxygen consumption are elevated upon Nat8l overexpression. Concordantly, expression levels of brown marker genes, such as Prdm16, Cidea, Pgc1α, Pparα, and particularly UCP1, are markedly elevated in these cells. Treatment with a PPARα antagonist indicates that the increase in UCP1 expression and oxygen consumption is PPARα-dependent. Nat8l knockdown in brown adipocytes has no impact on cellular triglyceride content, lipogenesis, or oxygen consumption, but lipolysis and brown marker gene expression are increased; the latter is also observed in BAT of Nat8l-KO mice. Interestingly, the expression of ATP-citrate lyase is increased in Nat8l-silenced adipocytes and BAT of Nat8l-KO mice, indicating a compensatory mechanism to sustain the acetyl-CoA pool once Nat8l levels are reduced. Taken together, our data show that Nat8l impacts on the brown adipogenic phenotype and suggests the existence of the NAT8L-driven NAA metabolism as a novel pathway to provide cytosolic acetyl-CoA for lipid synthesis in adipocytes.
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Affiliation(s)
- Ariane R. Pessentheiner
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria
| | - Helmut J. Pelzmann
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria
| | - Evelyn Walenta
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria
| | - Martina Schweiger
- the Institute for Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | | | | | - Dagmar Kolb
- Institute of Cell Biology, Histology, and Embryology, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria, ,the Core Facility Ultrastructure Analysis, Center for Medical Research, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Kyosuke Uno
- the Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan, and
| | - Toh Miyazaki
- the Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan, and
| | - Atsumi Nitta
- the Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan, and
| | - Dietmar Rieder
- the Division of Bioinformatics, Biocenter, Innsbruck Medical University, Innrain 80, 6020 Innsbruck, Austria
| | - Andreas Prokesch
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria
| | - Juliane G. Bogner-Strauss
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria, , To whom correspondence should be addressed: Petersgasse 14/5, 8010 Graz, Austria. Tel.: 43-316-873-5337; E-mail:
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Inoue T, Kobayashi K, Inoguchi T, Sonoda N, Maeda Y, Hirata E, Fujimura Y, Miura D, Hirano KI, Takayanagi R. Downregulation of adipose triglyceride lipase in the heart aggravates diabetic cardiomyopathy in db/db mice. Biochem Biophys Res Commun 2013; 438:224-9. [DOI: 10.1016/j.bbrc.2013.07.063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 10/26/2022]
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Czech MP, Tencerova M, Pedersen DJ, Aouadi M. Insulin signalling mechanisms for triacylglycerol storage. Diabetologia 2013; 56:949-64. [PMID: 23443243 PMCID: PMC3652374 DOI: 10.1007/s00125-013-2869-1] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 01/22/2013] [Indexed: 02/06/2023]
Abstract
Insulin signalling is uniquely required for storing energy as fat in humans. While de novo synthesis of fatty acids and triacylglycerol occurs mostly in liver, adipose tissue is the primary site for triacylglycerol storage. Insulin signalling mechanisms in adipose tissue that stimulate hydrolysis of circulating triacylglycerol, uptake of the released fatty acids and their conversion to triacylglycerol are poorly understood. New findings include (1) activation of DNA-dependent protein kinase to stimulate upstream stimulatory factor (USF)1/USF2 heterodimers, enhancing the lipogenic transcription factor sterol regulatory element binding protein 1c (SREBP1c); (2) stimulation of fatty acid synthase through AMP kinase modulation; (3) mobilisation of lipid droplet proteins to promote retention of triacylglycerol; and (4) upregulation of a novel carbohydrate response element binding protein β isoform that potently stimulates transcription of lipogenic enzymes. Additionally, insulin signalling through mammalian target of rapamycin to activate transcription and processing of SREBP1c described in liver may apply to adipose tissue. Paradoxically, insulin resistance in obesity and type 2 diabetes is associated with increased triacylglycerol synthesis in liver, while it is decreased in adipose tissue. This and other mysteries about insulin signalling and insulin resistance in adipose tissue make this topic especially fertile for future research.
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Affiliation(s)
- M P Czech
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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42
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Casado ME, Pastor O, Mariscal P, Canfrán-Duque A, Martínez-Botas J, Kraemer FB, Lasunción MA, Martín-Hidalgo A, Busto R. Hormone-sensitive lipase deficiency disturbs the fatty acid composition of mouse testis. Prostaglandins Leukot Essent Fatty Acids 2013; 88:227-33. [PMID: 23369366 DOI: 10.1016/j.plefa.2012.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 12/12/2012] [Accepted: 12/15/2012] [Indexed: 10/27/2022]
Abstract
Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of fatty acids from intracellular stores. In mice, HSL deficiency results in male sterility caused by a major defect in spermatogenesis. The testes contain high concentrations of PUFA and specific PUFA are essential for spermatogenesis. We investigated the fatty acid composition and the mRNA levels of key enzymes involved in fatty acid metabolism in testis of HSL-knockout mice. HSL deficiency altered fatty acid composition in the testis but not in plasma. The most important changes were decreases in the essential n-6 PUFA LNA and the n-3 PUFA ALA, and an increase in the corresponding synthesis intermediates C22:4n-6 and C22:5n-3 without changes in DPAn-6 or DHA acids. Mead acid, which has been associated with an essential fatty acid deficit leading to male infertility, was increased in the testis from HSL-knockout mice. Moreover, the expression of SCD-1, FADS1, and FADS2 was increased while expression of ELOVL2, an essential enzyme for the formation of very-long PUFA in testis, was decreased. Given the indispensability of these fatty acids for spermatogenesis, the changes in fatty acid metabolism observed in testes from HSL-knockout male mice may underlie the infertility of these animals.
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Affiliation(s)
- M E Casado
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS), E-28034 Madrid, Spain
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43
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Zierler KA, Jaeger D, Pollak NM, Eder S, Rechberger GN, Radner FPW, Woelkart G, Kolb D, Schmidt A, Kumari M, Preiss-Landl K, Pieske B, Mayer B, Zimmermann R, Lass A, Zechner R, Haemmerle G. Functional cardiac lipolysis in mice critically depends on comparative gene identification-58. J Biol Chem 2013; 288:9892-9904. [PMID: 23413028 DOI: 10.1074/jbc.m112.420620] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Efficient catabolism of cellular triacylglycerol (TG) stores requires the TG hydrolytic activity of adipose triglyceride lipase (ATGL). The presence of comparative gene identification-58 (CGI-58) strongly increased ATGL-mediated TG catabolism in cell culture experiments. Mutations in the genes coding for ATGL or CGI-58 in humans cause neutral lipid storage disease characterized by TG accumulation in multiple tissues. ATGL gene mutations cause a severe phenotype especially in cardiac muscle leading to cardiomyopathy that can be lethal. In contrast, CGI-58 gene mutations provoke severe ichthyosis and hepatosteatosis in humans and mice, whereas the role of CGI-58 in muscle energy metabolism is less understood. Here we show that mice lacking CGI-58 exclusively in muscle (CGI-58KOM) developed severe cardiac steatosis and cardiomyopathy linked to impaired TG catabolism and mitochondrial fatty acid oxidation. The marked increase in ATGL protein levels in cardiac muscle of CGI-58KOM mice was unable to compensate the lack of CGI-58. The addition of recombinant CGI-58 to cardiac lysates of CGI-58KOM mice completely reconstituted TG hydrolytic activities. In skeletal muscle, the lack of CGI-58 similarly provoked TG accumulation. The addition of recombinant CGI-58 increased TG hydrolytic activities in control and CGI-58KOM tissue lysates, elucidating the limiting role of CGI-58 in skeletal muscle TG catabolism. Finally, muscle CGI-58 deficiency affected whole body energy homeostasis, which is caused by impaired muscle TG catabolism and increased cardiac glucose uptake. In summary, this study demonstrates that functional muscle lipolysis depends on both CGI-58 and ATGL.
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Affiliation(s)
- Kathrin A Zierler
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Doris Jaeger
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Nina M Pollak
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Sandra Eder
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | | | - Franz P W Radner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Gerald Woelkart
- Department of Pharmacology and Toxicology, University of Graz, 8010 Graz, Austria
| | - Dagmar Kolb
- Center for Medical Research, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Albrecht Schmidt
- Department of Cardiology, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Manju Kumari
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | | | - Burkert Pieske
- Department of Cardiology, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, University of Graz, 8010 Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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Elahi-Moghaddam Z, Behnam-Rassouli M, Mahdavi-Shahri N, Hajinejad-Boshroue R, Khajouee E. Comparative study on the effects of type 1 and type 2 diabetes on structural changes and hormonal output of the adrenal cortex in male Wistar rats. J Diabetes Metab Disord 2013; 12:9. [PMID: 23497689 PMCID: PMC3598219 DOI: 10.1186/2251-6581-12-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/22/2013] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Diabetes is one of the most common endocrine disorders characterized by hyperglycemia due to defects in insulin secretion, insulin function, or both. Causing dysfunction in the body general metabolism, diabetes-induced chronic hyperglycemia leads to alterations in those endocrine glands involved in regulating the body metabolism. In this line, the present study has been conducted to investigate the effects of type 1 and type 2 diabetes on the structural changes and hormonal output of the adrenal cortex in male Wistar rat. METHODS Eighteen male Wistar rats were divided into three groups including control, experimental type 1 diabetes (subcutaneous injection of 135 mg/kg alloxan) and experimental type 2 diabetes (8 weeks treatment with drinking water containing 10% fructose). Two months after the induction of both types of diabetes, the level of blood biochemical factors (glucose, insulin, cortisol, triglycerides, cholesterol, LDL, and HDL) were measured. Structural changes of the adrenal cortex were then evaluated, using stereological techniques. RESULTS Serum biochemical analysis showed significant difference in the levels of glucose, triglycerides, insulin and cortisol in experimental groups, compared to the control. The results of structural alterations were also indicative of increase in adrenal cortex volume in both types of diabetes. CONCLUSION Probably through increasing HPA axis activity, type1 diabetes-induced hyperglycemia leads to adrenal hypertrophy and increase the hormonal output of adrenal gland.
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Affiliation(s)
- Zohreh Elahi-Moghaddam
- Biology Department, Faculty of Sciences, Islamic Azad University of Mashhad, Mashhad, Iran
| | | | - Naser Mahdavi-Shahri
- Biology Department, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
| | | | - Elaheh Khajouee
- Biology Department, Faculty of Sciences, Islamic Azad University of Mashhad, Mashhad, Iran
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Rossmeisl M, Kovar J, Syrovy I, Flachs P, Bobkova D, Kolar F, Poledne R, Kopecky J. Triglyceride-lowering Effect of Respiratory Uncoupling in White Adipose Tissue. ACTA ACUST UNITED AC 2012; 13:835-44. [PMID: 15919836 DOI: 10.1038/oby.2005.96] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Hypolipidemic drugs such as bezafibrate and thiazolidinediones are known to induce the expression of mitochondrial uncoupling proteins (UCPs) in white adipose tissue. To analyze the potential triglyceride (TG)-lowering effect of respiratory uncoupling in white fat, we evaluated systemic lipid metabolism in aP2-Ucp1 transgenic mice with ectopic expression of UCP1 in adipose tissue. RESEARCH METHODS AND PROCEDURES Hemizygous and homozygous transgenic mice and their nontransgenic littermates were fed chow or a high-fat diet for up to 3 months. Total TGs, nonesterified fatty acids, and the composition of plasma lipoproteins were analyzed. Hepatic TG production was measured in mice injected with Triton WR1339. Uptake and the use of fatty acids were estimated by measuring adipose tissue lipoprotein lipase activity and fatty acid oxidation, respectively. Adipose tissue gene expression was assessed by quantitative reverse transcriptase-polymerase chain reaction. RESULTS Transgene dosage and the high-fat diet interacted to markedly reduce plasma TGs. This was reflected by decreased concentrations of very-low-density lipoprotein particles in the transgenic mice. Despite normal hepatic TG secretion, the activity of lipoprotein lipase in epididymal fat was enhanced by the high-fat diet in the transgenic mice in a setting of decreased re-esterification and increased in situ fatty acid oxidation. DISCUSSION Respiratory uncoupling in white fat may lower plasma lipids by enhancing their in situ clearance and catabolism.
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Affiliation(s)
- Martin Rossmeisl
- Department of Adipose Tissue Biology, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic
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Cholesteryl ester accumulation and accelerated cholesterol absorption in intestine-specific hormone sensitive lipase-null mice. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1406-14. [PMID: 22842588 PMCID: PMC3459056 DOI: 10.1016/j.bbalip.2012.07.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 11/21/2022]
Abstract
Hormone sensitive lipase (HSL) regulates the hydrolysis of acylglycerols and cholesteryl esters (CE) in various cells and organs, including enterocytes of the small intestine. The physiological role of this enzyme in enterocytes, however, stayed elusive. In the present study we generated mice lacking HSL exclusively in the small intestine (HSLiKO) to investigate the impact of HSL deficiency on intestinal lipid metabolism and the consequences on whole body lipid homeostasis. Chow diet-fed HSLiKO mice showed unchanged plasma lipid concentrations. In addition, feeding with high fat/high cholesterol (HF/HC) diet led to unaltered triglyceride but increased plasma cholesterol concentrations and CE accumulation in the small intestine. The same effect was observed after an acute cholesterol load. Gavaging of radioactively labeled cholesterol resulted in increased abundance of radioactivity in plasma, liver and small intestine of HSLiKO mice 4 h post-gavaging. However, cholesterol absorption determined by the fecal dual-isotope ratio method revealed no significant difference, suggesting that HSLiKO mice take up the same amount of cholesterol but in an accelerated manner. mRNA expression levels of genes involved in intestinal cholesterol transport and esterification were unchanged but we observed downregulation of HMG-CoA reductase and synthase and consequently less intestinal cholesterol biosynthesis. Taken together our study demonstrates that the lack of intestinal HSL leads to CE accumulation in the small intestine, accelerated cholesterol absorption and decreased cholesterol biosynthesis, indicating that HSL plays an important role in intestinal cholesterol homeostasis.
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47
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Ogasawara J, Sakurai T, Kizaki T, Takahashi K, Ishida H, Izawa T, Toshinai K, Nakano N, Ohno H. Effect of physical exercise on lipolysis in white adipocytes. JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2012. [DOI: 10.7600/jpfsm.1.351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Choi SH, Ginsberg HN. Increased very low density lipoprotein (VLDL) secretion, hepatic steatosis, and insulin resistance. Trends Endocrinol Metab 2011; 22:353-63. [PMID: 21616678 PMCID: PMC3163828 DOI: 10.1016/j.tem.2011.04.007] [Citation(s) in RCA: 254] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Revised: 04/18/2011] [Accepted: 04/19/2011] [Indexed: 12/14/2022]
Abstract
Insulin resistance (IR) affects not only the regulation of carbohydrate metabolism but all aspects of lipid and lipoprotein metabolism. IR is associated with increased secretion of VLDL and increased plasma triglycerides, as well as with hepatic steatosis, despite the increased VLDL secretion. Here we link IR with increased VLDL secretion and hepatic steatosis at both the physiologic and molecular levels. Increased VLDL secretion, together with the downstream effects on high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) size, is proatherogenic. Hepatic steatosis is a risk factor for steatohepatitis and cirrhosis. Understanding the complex inter-relationships between IR and these abnormalities of liver lipid homeostasis will provide insights relevant to new therapies for these increasing clinical problems.
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Affiliation(s)
- Sung Hee Choi
- Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seoul, Korea
| | - Henry N Ginsberg
- Columbia University College of Physicians and Surgeons, New York, NY, USA
- whom correspondence should be addressed.
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49
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Kiefer FW, Neschen S, Pfau B, Legerer B, Neuhofer A, Kahle M, Hrabé de Angelis M, Schlederer M, Mair M, Kenner L, Plutzky J, Zeyda M, Stulnig TM. Osteopontin deficiency protects against obesity-induced hepatic steatosis and attenuates glucose production in mice. Diabetologia 2011; 54:2132-42. [PMID: 21562757 PMCID: PMC3131508 DOI: 10.1007/s00125-011-2170-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Accepted: 04/04/2011] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Obesity is strongly associated with the development of non-alcoholic fatty liver disease (NAFLD). The cytokine osteopontin (OPN) was recently shown to be involved in obesity-induced adipose tissue inflammation and reduced insulin response. Accumulating evidence links OPN to the pathogenesis of NAFLD. Here we aimed to identify the role of OPN in obesity-associated hepatic steatosis and impaired hepatic glucose metabolism. METHODS Wild-type (WT) and Opn (also known as Spp1) knockout (Opn (-/-)) mice were fed a high-fat or low-fat diet to study OPN effects in obesity-driven hepatic alterations. RESULTS We show that genetic OPN deficiency protected from obesity-induced hepatic steatosis, at least in part, by downregulating hepatic triacylglycerol synthesis. Conversely, absence of OPN promoted fat storage in adipose tissue thereby preventing the obesity-induced shift to ectopic fat accumulation in the liver. Euglycaemic-hyperinsulinaemic clamp studies revealed that insulin resistance and excess hepatic glucose production in obesity were significantly attenuated in Opn (-/-) mice. OPN deficiency markedly improved hepatic insulin signalling as shown by enhanced insulin receptor substrate-2 phosphorylation and prevented upregulation of the major hepatic transcription factor Forkhead box O1 and its gluconeogenic target genes. In addition, obesity-driven hepatic inflammation and macrophage accumulation was blocked by OPN deficiency. CONCLUSIONS/INTERPRETATION Our data strongly emphasise OPN as mediator of obesity-associated hepatic alterations including steatosis, inflammation, insulin resistance and excess gluconeogenesis. Targeting OPN action could therefore provide a novel therapeutic strategy to prevent obesity-related complications such as NAFLD and type 2 diabetes.
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Affiliation(s)
- F. W. Kiefer
- Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - S. Neschen
- Institute of Experimental Genetics, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - B. Pfau
- Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - B. Legerer
- Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - A. Neuhofer
- Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - M. Kahle
- Institute of Experimental Genetics, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - M. Hrabé de Angelis
- Institute of Experimental Genetics, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - M. Schlederer
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
| | - M. Mair
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
| | - L. Kenner
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
| | - J. Plutzky
- Department of Medicine, Brigham and Women’s Hospital Boston, Cardiovascular Division, Harvard Medical School, Boston, MA USA
| | - M. Zeyda
- Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - T. M. Stulnig
- Department of Medicine III, Clinical Division of Endocrinology and Metabolism, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
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Wang K, Edmondson AC, Li M, Gao F, Qasim AN, Devaney JM, Burnett MS, Waterworth DM, Mooser V, Grant SFA, Epstein SE, Reilly MP, Hakonarson H, Rader DJ. Pathway-Wide Association Study Implicates Multiple Sterol Transport and Metabolism Genes in HDL Cholesterol Regulation. Front Genet 2011; 2:41. [PMID: 22303337 PMCID: PMC3268595 DOI: 10.3389/fgene.2011.00041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 06/21/2011] [Indexed: 12/30/2022] Open
Abstract
Pathway-based association methods have been proposed to be an effective approach in identifying disease genes, when single-marker association tests do not have sufficient power. The analysis of quantitative traits may be benefited from these approaches, by sampling from two extreme tails of the distribution. Here we tested a pathway association approach on a small genome-wide association study (GWAS) on 653 subjects with extremely high high-density lipoprotein cholesterol (HDL-C) levels and 784 subjects with low HDL-C levels. We identified 102 genes in the sterol transport and metabolism pathways that collectively associate with HDL-C levels, and replicated these association signals in an independent GWAS. Interestingly, the pathways include 18 genes implicated in previous GWAS on lipid traits, suggesting that genuine HDL-C genes are highly enriched in these pathways. Additionally, multiple biologically relevant loci in the pathways were not detected by previous GWAS, including genes implicated in previous candidate gene association studies (such as LEPR, APOA2, HDLBP, SOAT2), genes that cause Mendelian forms of lipid disorders (such as DHCR24), and genes expressing dyslipidemia phenotypes in knockout mice (such as SOAT1, PON1). Our study suggests that sampling from two extreme tails of a quantitative trait and examining genetic pathways may yield biological insights from smaller samples than are generally required using single-marker analysis in large-scale GWAS. Our results also implicate that functionally related genes work together to regulate complex quantitative traits, and that future large-scale studies may benefit from pathway-association approaches to identify novel pathways regulating HDL-C levels.
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Affiliation(s)
- Kai Wang
- Center for Applied Genomics, Children's Hospital of Philadelphia Philadelphia, PA, USA
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