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Choi S, Kang JG, Tran YTH, Jeong SH, Park KY, Shin H, Kim YH, Park M, Nahmgoong H, Seol T, Jeon H, Kim Y, Park S, Kim HJ, Kim MS, Li X, Bou Sleiman M, Lee E, Choi J, Eisenbarth D, Lee SH, Cho S, Moore DD, Auwerx J, Kim IY, Kim JB, Park JE, Lim DS, Suh JM. Hippo-YAP/TAZ signalling coordinates adipose plasticity and energy balance by uncoupling leptin expression from fat mass. Nat Metab 2024; 6:847-860. [PMID: 38811804 PMCID: PMC11136666 DOI: 10.1038/s42255-024-01045-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 04/10/2024] [Indexed: 05/31/2024]
Abstract
Adipose tissues serve as an energy reservoir and endocrine organ, yet the mechanisms that coordinate these functions remain elusive. Here, we show that the transcriptional coregulators, YAP and TAZ, uncouple fat mass from leptin levels and regulate adipocyte plasticity to maintain metabolic homeostasis. Activating YAP/TAZ signalling in adipocytes by deletion of the upstream regulators Lats1 and Lats2 results in a profound reduction in fat mass by converting mature adipocytes into delipidated progenitor-like cells, but does not cause lipodystrophy-related metabolic dysfunction, due to a paradoxical increase in circulating leptin levels. Mechanistically, we demonstrate that YAP/TAZ-TEAD signalling upregulates leptin expression by directly binding to an upstream enhancer site of the leptin gene. We further show that YAP/TAZ activity is associated with, and functionally required for, leptin regulation during fasting and refeeding. These results suggest that adipocyte Hippo-YAP/TAZ signalling constitutes a nexus for coordinating adipose tissue lipid storage capacity and systemic energy balance through the regulation of adipocyte plasticity and leptin gene transcription.
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Affiliation(s)
- Sungwoo Choi
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Ju-Gyeong Kang
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Yen T H Tran
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Sun-Hye Jeong
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Kun-Young Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Hyemi Shin
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Young Hoon Kim
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Myungsun Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Hahn Nahmgoong
- National Creative Research Initiatives Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Taejun Seol
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Haeyon Jeon
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Yeongmin Kim
- Department of Health Sciences and Technology, Gachon Advanced Institute for Health Sciences & Technology, Gachon University, Incheon, Republic of Korea
| | - Sanghee Park
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Hee-Joo Kim
- Department of Health Sciences and Technology, Gachon Advanced Institute for Health Sciences & Technology, Gachon University, Incheon, Republic of Korea
| | - Min-Seob Kim
- Department of Fundamental Environment Research, Environmental Measurement and Analysis Center, National Institute of Environmental Research, Incheon, Republic of Korea
| | - Xiaoxu Li
- Laboratory of Integrative Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Maroun Bou Sleiman
- Laboratory of Integrative Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Eries Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Jinhyuk Choi
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - David Eisenbarth
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Sang Heon Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Suhyeon Cho
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - David D Moore
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Il-Young Kim
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Jae Bum Kim
- National Creative Research Initiatives Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jong-Eun Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Dae-Sik Lim
- National Creative Research Center for Cell Plasticity, KAIST Stem Cell Center, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.
| | - Jae Myoung Suh
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.
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García-López MÁ, Mora A, Corrales P, Pons T, Sánchez de Diego A, Talavera Gutiérrez A, van Wely KHM, Medina-Gómez G, Sabio G, Martínez-A C, Fischer T. DIDO is necessary for the adipogenesis that promotes diet-induced obesity. Proc Natl Acad Sci U S A 2024; 121:e2300096121. [PMID: 38194457 PMCID: PMC10801893 DOI: 10.1073/pnas.2300096121] [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: 01/13/2023] [Accepted: 10/24/2023] [Indexed: 01/11/2024] Open
Abstract
The prevalence of overweight and obesity continues to rise in the population worldwide. Because it is an important predisposing factor for cancer, cardiovascular diseases, diabetes mellitus, and COVID-19, obesity reduces life expectancy. Adipose tissue (AT), the main fat storage organ with endocrine capacity, plays fundamental roles in systemic metabolism and obesity-related diseases. Dysfunctional AT can induce excess or reduced body fat (lipodystrophy). Dido1 is a marker gene for stemness; gene-targeting experiments compromised several functions ranging from cell division to embryonic stem cell differentiation, both in vivo and in vitro. We report that mutant mice lacking the DIDO N terminus show a lean phenotype. This consists of reduced AT and hypolipidemia, even when mice are fed a high-nutrient diet. DIDO mutation caused hypothermia due to lipoatrophy of white adipose tissue (WAT) and dermal fat thinning. Deep sequencing of the epididymal white fat (Epi WAT) transcriptome supported Dido1 control of the cellular lipid metabolic process. We found that, by controlling the expression of transcription factors such as C/EBPα or PPARγ, Dido1 is necessary for adipocyte differentiation, and that restoring their expression reestablished adipogenesis capacity in Dido1 mutants. Our model differs from other lipodystrophic mice and could constitute a new system for the development of therapeutic intervention in obesity.
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Affiliation(s)
- María Ángeles García-López
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Campus, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - Alfonso Mora
- Centro Nacional de Investigaciones Cardiovasculares, Madrid28029, Spain
| | - Patricia Corrales
- Department of Basic Sciences of Health, Area of Biochemistry and Molecular Biology, Universidad Rey Juan Carlos, Alcorcon28922, Spain
| | - Tirso Pons
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Campus, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - Ainhoa Sánchez de Diego
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Campus, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - Amaia Talavera Gutiérrez
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Campus, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - Karel H. M. van Wely
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Campus, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - Gema Medina-Gómez
- Department of Basic Sciences of Health, Area of Biochemistry and Molecular Biology, Universidad Rey Juan Carlos, Alcorcon28922, Spain
| | - Guadalupe Sabio
- Centro Nacional de Investigaciones Cardiovasculares, Madrid28029, Spain
| | - Carlos Martínez-A
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Campus, Universidad Autónoma de Madrid, Madrid28049, Spain
| | - Thierry Fischer
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Campus, Universidad Autónoma de Madrid, Madrid28049, Spain
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Adipose tissue macrophages and their role in obesity-associated insulin resistance: an overview of the complex dynamics at play. Biosci Rep 2023; 43:232519. [PMID: 36718668 PMCID: PMC10011338 DOI: 10.1042/bsr20220200] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 01/18/2023] [Accepted: 01/26/2023] [Indexed: 02/01/2023] Open
Abstract
Obesity, a major global health concern, is characterized by serious imbalance between energy intake and expenditure leading to excess accumulation of fat in adipose tissue (AT). A state of chronic low-grade AT inflammation is prevalent during obesity. The adipose tissue macrophages (ATM) with astounding heterogeneity and complex regulation play a decisive role in mediating obesity-induced insulin resistance. Adipose-derived macrophages were broadly classified as proinflammatory M1 and anti-inflammatory M2 subtypes but recent reports have proclaimed several novel and intermediate profiles, which are crucial in understanding the dynamics of macrophage phenotypes during development of obesity. Lipid-laden hypertrophic adipocytes release various chemotactic signals that aggravate macrophage infiltration into AT skewing toward mostly proinflammatory status. The ratio of M1-like to M2-like macrophages is increased substantially resulting in copious secretion of proinflammatory mediators such as TNFα, IL-6, IL-1β, MCP-1, fetuin-A (FetA), etc. further worsening insulin resistance. Several AT-derived factors could influence ATM content and activation. Apart from being detrimental, ATM exerts beneficial effects during obesity. Recent studies have highlighted the prime role of AT-resident macrophage subpopulations in not only effective clearance of excess fat and dying adipocytes but also in controlling vascular integrity, adipocyte secretions, and fibrosis within obese AT. The role of ATM subpopulations as friend or foe is determined by an intricate interplay of such factors arising within hyperlipidemic microenvironment of obese AT. The present review article highlights some of the key research advances in ATM function and regulation, and appreciates the complex dynamics of ATM in the pathophysiologic scenario of obesity-associated insulin resistance.
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Yeh YS, Iwase M, Kawarasaki S, Kwon J, Rodriguez-Velez A, Zhang X, Jeong SJ, Goto T, Razani B. Subcutaneous Transplantation of White Adipose Tissue. Methods Mol Biol 2023; 2662:183-192. [PMID: 37076681 DOI: 10.1007/978-1-0716-3167-6_16] [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: 04/21/2023]
Abstract
In the research setting, white adipose tissue (WAT) transplantation, also known as fat transplantation, is often used to understand the physiological function of adipocytes or associated stromal vascular cells such as macrophages in the context of local and systemic metabolism. The mouse is the most common animal model used where WAT from a donor is transferred either to a subcutaneous site of the same organism or to a subcutaneous region of a recipient. Here, we describe in detail the procedure for heterologous fat transplantation, and, given the need for survival surgery, peri- and postoperative care and subsequent histological confirmation of fat grafts will also be discussed.
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Affiliation(s)
- Yu-Sheng Yeh
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine and UPMC, Pittsburgh, PA, USA
- Pittsburgh VA Medical Center, Pittsburgh, PA, USA
| | - Mari Iwase
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- Division of Oncology, Department of Medicine, Washington University School of Medicine, Pittsburgh, PA, USA
| | - Satoko Kawarasaki
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Jungin Kwon
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Astrid Rodriguez-Velez
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Xiangyu Zhang
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine and UPMC, Pittsburgh, PA, USA
- Pittsburgh VA Medical Center, Pittsburgh, PA, USA
| | - Se-Jin Jeong
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tsuyoshi Goto
- Research Unit for Physiological Chemistry, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Babak Razani
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.
- Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine and UPMC, Pittsburgh, PA, USA.
- Pittsburgh VA Medical Center, Pittsburgh, PA, USA.
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Daquinag AC, Gao Z, Yu Y, Kolonin MG. Endothelial TrkA coordinates vascularization and innervation in thermogenic adipose tissue and can be targeted to control metabolism. Mol Metab 2022; 63:101544. [PMID: 35835372 PMCID: PMC9310128 DOI: 10.1016/j.molmet.2022.101544] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 06/24/2022] [Accepted: 07/05/2022] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVE Brown adipogenesis and thermogenesis in brown and beige adipose tissue (AT) involve vascular remodeling and sympathetic neuronal guidance. Here, we investigated the molecular mechanism coordinating these processes. METHODS We used mouse models to identify the molecular target of a peptide CPATAERPC homing to the endothelium of brown and beige AT. RESULTS We demonstrate that CPATAERPC mimics nerve growth factor (NGF) and identify a low molecular weight isoform of NGF receptor, TrkA, as the CPATAERPC cell surface target. We show that the expression of truncated endothelial TrkA is selective for brown and subcutaneous AT. Analysis of mice with endothelium-specific TrkA knockout revealed the role of TrkA in neuro-vascular coordination supporting the thermogenic function of brown adipocytes. A hunter-killer peptide D-BAT, composed of CPATAERPC and a pro-apoptotic domain, induced cell death in the endothelium and adipocytes. This resulted in thermogenesis impairment, and predisposed mice to obesity and glucose intolerance. We also tested if this treatment can inhibit the tumor recruitment of lipids mobilized from adipocytes from adjacent AT. Indeed, in a mouse model of breast cancer D-BAT suppressed tumor-associated AT lipolysis, which resulted in reduced fatty acid utilization by cancer cells. CONCLUSION Our study demonstrates that TrkA signaling in the endothelium supports neuro-vascular coordination enabling beige adipogenesis.
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Affiliation(s)
- Alexes C Daquinag
- The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhanguo Gao
- The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Yongmei Yu
- The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Mikhail G Kolonin
- The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA.
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Diaz-Canestro C, Xu A. Impact of Different Adipose Depots on Cardiovascular Disease. J Cardiovasc Pharmacol 2021; 78:S30-S39. [PMID: 34840259 DOI: 10.1097/fjc.0000000000001131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/05/2021] [Indexed: 12/13/2022]
Abstract
ABSTRACT Adipose tissue (AT)-derived factors contribute to the regulation of cardiovascular homeostasis, thereby playing an important role in cardiovascular health and disease. In obesity, AT expands and becomes dysfunctional, shifting its secretory profile toward a proinflammatory state associated with deleterious effects on the cardiovascular system. AT in distinct locations (ie, adipose depots) differs in crucial phenotypic variables, including inflammatory and secretory profile, cellular composition, lipolytic activity, and gene expression. Such heterogeneity among different adipose depots may explain contrasting cardiometabolic risks associated with different obesity phenotypes. In this respect, central obesity, defined as the accumulation of AT in the abdominal region, leads to higher risk of cardiometabolic alterations compared with the accumulation of AT in the gluteofemoral region (ie, peripheral obesity). The aim of this review was to provide an updated summary of clinical and experimental evidence supporting the differential roles of different adipose depots in cardiovascular disease and to discuss the molecular basis underlying the differences of adipose depots in the regulation of cardiovascular function.
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Affiliation(s)
- Candela Diaz-Canestro
- State Key Laboratory of Pharmaceutical Biotechnology, the University of Hong Kong, Hong Kong, China
- Department of Medicine, the University of Hong Kong, Hong Kong, China; and
| | - Aimin Xu
- State Key Laboratory of Pharmaceutical Biotechnology, the University of Hong Kong, Hong Kong, China
- Department of Medicine, the University of Hong Kong, Hong Kong, China; and
- Department of Pharmacology and Pharmacy, the University of Hong Kong, Hong Kong, China
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Independent Dose-Response Associations between Fetuin-A and Lean Nonalcoholic Fatty Liver Disease. Nutrients 2021; 13:nu13092928. [PMID: 34578806 PMCID: PMC8468081 DOI: 10.3390/nu13092928] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 12/13/2022] Open
Abstract
Patients with lean NAFLD make up an increasing subset of liver disease patients. The association between lean NAFLD and feutin-A, which serves as a hepatokine and adipokine, has never been examined. Our study aimed to explore the association of serum fetuin-A among lean and non-lean patients. The study comprised 606 adults from the community, stratified into lean or non-lean (BMI </≥ 24 kg/m2) and NAFLD or non-NAFLD (scoring of ultrasonographic fatty liver indicator, US-FLI ≥ 2/< 2). Multivariate logistic regression analyses were performed to estimate the odds ratio of having NAFLD among the tertiles of fetuin-A after adjustment. The least square means were computed by general linear models to estimate marginal means of the serum fetuin-A concentrations in relation to the NAFLD groups. The odds ratio (OR) of having NAFLD for the highest versus the lowest tertile of fetuin-A was 2.62 (95% CI: 1.72–3.98; p for trend < 0.001). Stratifying by BMI, the OR of having lean NAFLD for the highest versus the lowest tertile of fetuin-A was 2.09 (95% CI: 1.09–3.98; p for trend 0.026), while non-lean NAFLD had no significant association with the fetuin-A gradient after adjustments. Fetuin-A was positively associated with lean NAFLD after adjusting for central obesity and insulin resistance.
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JAK/STAT inhibitor therapy partially rescues the lipodystrophic autoimmune phenotype in Clec16a KO mice. Sci Rep 2021; 11:7372. [PMID: 33795715 PMCID: PMC8016875 DOI: 10.1038/s41598-021-86493-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 03/08/2021] [Indexed: 02/06/2023] Open
Abstract
CLEC16A is implicated in multiple autoimmune diseases. We generated an inducible whole-body knockout (KO), Clec16aΔUBC mice to address the role of CLEC16A loss of function. KO mice exhibited loss of adipose tissue and severe weight loss in response to defective autophagic flux and exaggerated endoplasmic reticulum (ER) stress and robust cytokine storm. KO mice were glucose tolerant and displayed a state of systemic inflammation with elevated antibody levels, including IgM, IgA, Ig2b and IgG3, significantly reduced circulating insulin levels in the presence of normal food consumption. Metabolic analysis revealed disturbances in the lipid profile, white adipose decreasing concomitantly with enhanced inflammatory response, and energy wasting. Mechanistically, endoplasmic reticulum (ER) stress triggers excessive hormone sensitive lipases (HSL) mediated lipolysis which contributes to adipose inflammation via activation of JAK-STAT, stress kinases (ERK1/2, P38, JNK), and release of multiple proinflammatory mediators. Treatment with a JAK-STAT inhibitor (tofacitinib) partially rescued the inflammatory lipodystrophic phenotype and improved survival of Clec16aΔUBC mice by silencing cytokine release and modulating ER stress, lipolysis, mitophagy and autophagy. These results establish a mechanistic link between CLEC16A, lipid metabolism and the immune system perturbations. In summary, our Clec16aΔUBC mouse model highlights multifaceted roles of Clec16a in normal physiology, including a novel target for weight regulation and mutation-induced pathophysiology.
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Dearden L, Buller S, Furigo IC, Fernandez-Twinn DS, Ozanne SE. Maternal obesity causes fetal hypothalamic insulin resistance and disrupts development of hypothalamic feeding pathways. Mol Metab 2020; 42:101079. [PMID: 32919096 PMCID: PMC7549144 DOI: 10.1016/j.molmet.2020.101079] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 12/16/2022] Open
Abstract
Objective Perinatal exposure to maternal obesity results in predisposition of offspring to develop obesity later in life. Increased weight gain in offspring exposed to maternal obesity is usually associated with hyperphagia, implicating altered central regulation of food intake as a cause. We aimed to define how maternal obesity impacts early development of the hypothalamus to program lasting dysfunction in feeding regulatory pathways. Methods Mice offspring of diet-induced obese mothers were compared to the offspring of lean control mothers. We analysed gene expression in the fetal hypothalamus, alongside neurosphere assays to investigate the effects of maternal obesity on neural progenitor cell proliferation in vitro. Western blotting was used to investigate the insulin signalling pathway in the fetal hypothalamus. Characterisation of cell type and neuropeptide profile in adulthood was linked with analyses of feeding behaviour. Results There was a reduction in the expression of proliferative genes in the fetal hypothalamus of offspring exposed to maternal obesity. This reduction in proliferation was maintained in vitro when hypothalamic neural progenitor cells were grown as neurospheres. Hypothalamic fetal gene expression and neurosphere growth correlated with maternal body weight and insulin levels. Foetuses of obese mothers showed hypothalamic insulin resistance, which may be causative of reduced proliferation. Furthermore, maternal obesity activated the Notch signalling pathway in neonatal offspring hypothalamus, resulting in decreased neurogenesis. Adult offspring of obese mothers displayed an altered ratio of anorexigenic and orexigenic signals in the arcuate nucleus, associated with an inability to maintain energy homeostasis when metabolically challenged. Conclusions These findings show that maternal obesity alters the molecular signature in the developing hypothalamus, which is associated with disrupted growth and development of hypothalamic precursor cells and defective feeding regulation in adulthood. This is the first report of fetal hypothalamic insulin resistance in an obese pregnancy and suggests a mechanism by which maternal obesity causes permanent changes to hypothalamic structure and function. Exposure to maternal obesity reduces hypothalamic neural progenitor cell growth. Maternal obesity activates hypothalamic Notch signalling and reduces neurogenesis. Maternal obesity causes fetal hypothalamic insulin resistance. Maternal obesity alters the ratio of anorexigenic/orexigenic signals in ARC. Changes in food intake precede increased adiposity in offspring of obese dams.
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Affiliation(s)
- L Dearden
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge, CB20QQ, United Kingdom.
| | - S Buller
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge, CB20QQ, United Kingdom
| | - I C Furigo
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge, CB20QQ, United Kingdom
| | - D S Fernandez-Twinn
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge, CB20QQ, United Kingdom
| | - S E Ozanne
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge, CB20QQ, United Kingdom
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Petäistö T, Vicente D, Mäkelä KA, Finnilä MA, Miinalainen I, Koivunen J, Izzi V, Aikio M, Karppinen S, Devarajan R, Thevenot J, Herzig K, Heljasvaara R, Pihlajaniemi T. Lack of collagen XVIII leads to lipodystrophy and perturbs hepatic glucose and lipid homeostasis. J Physiol 2020; 598:3373-3393. [DOI: 10.1113/jp279559] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/21/2020] [Indexed: 01/13/2023] Open
Affiliation(s)
- Tiina Petäistö
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
| | - David Vicente
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
| | - Kari A. Mäkelä
- Research Unit of Biomedicine Biocenter Oulu and Faculty of Medicine University of Oulu Oulu Finland
| | - Mikko A. Finnilä
- Research Unit of Medical Imaging Physics and Technology Faculty of Medicine University of Oulu Oulu Finland
| | | | - Jarkko Koivunen
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
| | - Valerio Izzi
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
| | - Mari Aikio
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
| | - Sanna‐Maria Karppinen
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
| | - Raman Devarajan
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
| | - Jerome Thevenot
- Research Unit of Medical Imaging Physics and Technology Faculty of Medicine University of Oulu Oulu Finland
| | - Karl‐Heinz Herzig
- Research Unit of Biomedicine Biocenter Oulu and Faculty of Medicine University of Oulu Oulu Finland
| | - Ritva Heljasvaara
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
- Department of Biomedicine Centre for Cancer Biomarkers (CCBIO) University of Bergen Bergen Norway
| | - Taina Pihlajaniemi
- Oulu Center for Cell‐Matrix Research Faculty of Biochemistry and Molecular Medicine University of Oulu Oulu Finland
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Bruder-Nascimento T, Kress TC, Belin de Chantemele EJ. Recent advances in understanding lipodystrophy: a focus on lipodystrophy-associated cardiovascular disease and potential effects of leptin therapy on cardiovascular function. F1000Res 2019; 8:F1000 Faculty Rev-1756. [PMID: 31656583 PMCID: PMC6798323 DOI: 10.12688/f1000research.20150.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/08/2019] [Indexed: 01/09/2023] Open
Abstract
Lipodystrophy is a disease characterized by a partial or total absence of adipose tissue leading to severe metabolic derangements including marked insulin resistance, type 2 diabetes, hypertriglyceridemia, and steatohepatitis. Lipodystrophy is also a source of major cardiovascular disorders which, in addition to hepatic failure and infection, contribute to a significant reduction in life expectancy. Metreleptin, the synthetic analog of the adipocyte-derived hormone leptin and current therapy of choice for patients with lipodystrophy, successfully improves metabolic function. However, while leptin has been associated with hypertension, vascular diseases, and inflammation in the context of obesity, it remains unknown whether its daily administration could further impair cardiovascular function in patients with lipodystrophy. The goal of this short review is to describe the cardiovascular phenotype of patients with lipodystrophy, speculate on the etiology of the disorders, and discuss how the use of murine models of lipodystrophy could be beneficial to address the question of the contribution of leptin to lipodystrophy-associated cardiovascular disease.
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Affiliation(s)
- Thiago Bruder-Nascimento
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA, USA
- Department of Pediatrics, Division of Endocrinology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Taylor C. Kress
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Eric J. Belin de Chantemele
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA, USA
- Department of Medicine, Section of Cardiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
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12
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Chartoumpekis DV, Yagishita Y, Fazzari M, Palliyaguru DL, Rao UN, Zaravinos A, Khoo NK, Schopfer FJ, Weiss KR, Michalopoulos GK, Sipula I, O'Doherty RM, Kensler TW, Wakabayashi N. Nrf2 prevents Notch-induced insulin resistance and tumorigenesis in mice. JCI Insight 2018. [PMID: 29515034 DOI: 10.1172/jci.insight.97735] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Insulin resistance is associated with increased incidence and enhanced progression of cancers. However, little is known about strategies that can effectively ameliorate insulin resistance and consequently halt cancer progression. Herein, we propose that the transcription factor Nrf2 (also known as Nfe2l2) may be such a target, given its central role in disease prevention. To this end, we developed a mouse that overexpresses the Notch intracellular domain in adipocytes (AdNICD), leading to lipodystrophy-induced severe insulin resistance and subsequent development of sarcomas, as a model reflecting that Notch signaling is deregulated in cancers and shows positive associations with insulin resistance and fatty liver disease in humans. Nrf2 pathway activation was achieved by knocking down Keap1, a repressor of Nrf2, in the AdNICD background. Constitutively enhanced Nrf2 signaling in this setting led to prevention of hepatic steatosis, dyslipidemia, and insulin resistance by repressing hepatic lipogenic pathways and restoration of the hepatic fatty acid profile to control levels. This protective effect of Nrf2 against diabetes extended to significant reduction and delay in sarcoma incidence and latency. Our study highlights that the Nrf2 pathway, which has been induced by small molecules in clinical trials, is a potential therapeutic target against insulin resistance and subsequent risk of cancer.
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Affiliation(s)
- Dionysios V Chartoumpekis
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yoko Yagishita
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Marco Fazzari
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Fondazione Ri.MED, Palermo, Italy
| | - Dushani L Palliyaguru
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Uma Nm Rao
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Apostolos Zaravinos
- Department of Life Sciences, School of Sciences, European University Cyprus, Nicosia, Cyprus
| | - Nicholas Kh Khoo
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Francisco J Schopfer
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | | | - Ian Sipula
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Robert M O'Doherty
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas W Kensler
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nobunao Wakabayashi
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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13
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Anunciado-Koza RP, Manuel J, Mynatt RL, Zhang J, Kozak LP, Koza RA. Diet-induced adipose tissue expansion is mitigated in mice with a targeted inactivation of mesoderm specific transcript (Mest). PLoS One 2017. [PMID: 28640866 PMCID: PMC5481029 DOI: 10.1371/journal.pone.0179879] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Interindividual variation of white adipose tissue (WAT) expression of mesoderm specific transcript (Mest), a paternally-expressed imprinted gene belonging to the α/β-hydrolase fold protein family, becomes apparent among genetically inbred mice fed high fat diet (HFD) and is positively associated with adipose tissue expansion (ATE). To elucidate a role for MEST in ATE, mice were developed with global and adipose tissue inactivation of Mest. Mice with homozygous (MestgKO) and paternal allelic (MestpKO) inactivation of Mest were born at expected Mendelian frequencies, showed no behavioral or physical abnormalities, and did not perturb expression of the Mest locus-derived microRNA miR-335. MestpKO mice fed HFD showed reduced ATE and adipocyte hypertrophy, improved glucose tolerance, and reduced WAT expression of genes associated with hypoxia and inflammation compared to littermate controls. Remarkably, caloric intake and energy expenditure were unchanged between genotypes. Mice with adipose tissue inactivation of Mest were phenotypically similar to MestpKO, supporting a role for WAT MEST in ATE. Global profiling of WAT gene expression of HFD-fed control and MestpKO mice detected few differences between genotypes; nevertheless, genes with reduced expression in MestpKO mice were associated with immune processes and consistent with improved glucose homeostasis. Ear-derived mesenchymal stem cells (EMSC) from MestgKO mice showed no differences in adipogenic differentiation compared to control cells unless challenged by shRNA knockdown of Gpat4, an enzyme that mediates lipid accumulation in adipocytes. Reduced adipogenic capacity of EMSC from MestgKO after Gpat4 knockdown suggests that MEST facilitates lipid accumulation in adipocytes. Our data suggests that reduced diet-induced ATE in MEST-deficient mice diminishes hypoxia and inflammation in WAT leading to improved glucose tolerance and insulin sensitivity. Since inactivation of Mest in mice has minimal additional effects aside from reduction of ATE, an intervention that mitigates MEST function in adipocytes is a plausible strategy to obviate obesity and type-2-diabetes.
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Affiliation(s)
- Rea P. Anunciado-Koza
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, United States of America
| | - Justin Manuel
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, United States of America
| | - Randall L. Mynatt
- Transgenics Core Facility, Pennington Biomedical Research Center, LSU System, Baton Rouge, Louisiana, United States of America
| | - Jingying Zhang
- Transgenics Core Facility, Pennington Biomedical Research Center, LSU System, Baton Rouge, Louisiana, United States of America
| | - Leslie P. Kozak
- Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland
| | - Robert A. Koza
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, United States of America
- * E-mail:
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14
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Lee JH, Han JS, Kong J, Ji Y, Lv X, Lee J, Li P, Kim JB. Protein Kinase A Subunit Balance Regulates Lipid Metabolism in Caenorhabditis elegans and Mammalian Adipocytes. J Biol Chem 2016; 291:20315-28. [PMID: 27496951 DOI: 10.1074/jbc.m116.740464] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Indexed: 11/06/2022] Open
Abstract
Protein kinase A (PKA) is a cyclic AMP (cAMP)-dependent protein kinase composed of catalytic and regulatory subunits and involved in various physiological phenomena, including lipid metabolism. Here we demonstrated that the stoichiometric balance between catalytic and regulatory subunits is crucial for maintaining basal PKA activity and lipid homeostasis. To uncover the potential roles of each PKA subunit, Caenorhabditis elegans was used to investigate the effects of PKA subunit deficiency. In worms, suppression of PKA via RNAi resulted in severe phenotypes, including shortened life span, decreased egg laying, reduced locomotion, and altered lipid distribution. Similarly, in mammalian adipocytes, suppression of PKA regulatory subunits RIα and RIIβ via siRNAs potently stimulated PKA activity, leading to potentiated lipolysis without increasing cAMP levels. Nevertheless, insulin exerted anti-lipolytic effects and restored lipid droplet integrity by antagonizing PKA action. Together, these data implicate the importance of subunit stoichiometry as another regulatory mechanism of PKA activity and lipid metabolism.
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Affiliation(s)
- Jung Hyun Lee
- From the Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, 08862 Seoul, Korea
| | - Ji Seul Han
- From the Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, 08862 Seoul, Korea
| | - Jinuk Kong
- From the Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, 08862 Seoul, Korea
| | - Yul Ji
- From the Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, 08862 Seoul, Korea
| | - Xuchao Lv
- the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China and
| | - Junho Lee
- From the Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, 08862 Seoul, Korea, the Department of Biophysics and Chemical Biology, Seoul National University, Seoul 08862, Korea
| | - Peng Li
- the MOE Key Laboratory of Bioinformatics and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China and
| | - Jae Bum Kim
- From the Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, 08862 Seoul, Korea,
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15
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Radović B, Vujić N, Leopold C, Schlager S, Goeritzer M, Patankar JV, Korbelius M, Kolb D, Reindl J, Wegscheider M, Tomin T, Birner-Gruenberger R, Schittmayer M, Groschner L, Magnes C, Diwoky C, Frank S, Steyrer E, Du H, Graier WF, Madl T, Kratky D. Lysosomal acid lipase regulates VLDL synthesis and insulin sensitivity in mice. Diabetologia 2016; 59:1743-52. [PMID: 27153842 PMCID: PMC4930475 DOI: 10.1007/s00125-016-3968-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/29/2016] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS Lysosomal acid lipase (LAL) hydrolyses cholesteryl esters and triacylglycerols (TG) within lysosomes to mobilise NEFA and cholesterol. Since LAL-deficient (Lal (-/-) ) mice suffer from progressive loss of adipose tissue and severe accumulation of lipids in hepatic lysosomes, we hypothesised that LAL deficiency triggers alternative energy pathway(s). METHODS We studied metabolic adaptations in Lal (-/-) mice. RESULTS Despite loss of adipose tissue, Lal (-/-) mice show enhanced glucose clearance during insulin and glucose tolerance tests and have increased uptake of [(3)H]2-deoxy-D-glucose into skeletal muscle compared with wild-type mice. In agreement, fasted Lal (-/-) mice exhibit reduced glucose and glycogen levels in skeletal muscle. We observed 84% decreased plasma leptin levels and significantly reduced hepatic ATP, glucose, glycogen and glutamine concentrations in fed Lal (-/-) mice. Markedly reduced hepatic acyl-CoA concentrations decrease the expression of peroxisome proliferator-activated receptor α (PPARα) target genes. However, treatment of Lal (-/-) mice with the PPARα agonist fenofibrate further decreased plasma TG (and hepatic glucose and glycogen) concentrations in Lal (-/-) mice. Depletion of hepatic nuclear factor 4α and forkhead box protein a2 in fasted Lal (-/-) mice might be responsible for reduced expression of microsomal TG transfer protein, defective VLDL synthesis and drastically reduced plasma TG levels. CONCLUSIONS/INTERPRETATION Our findings indicate that neither activation nor inactivation of PPARα per se but rather the availability of hepatic acyl-CoA concentrations regulates VLDL synthesis and subsequent metabolic adaptations in Lal (-/-) mice. We conclude that decreased plasma VLDL production enhances glucose uptake into skeletal muscle to compensate for the lack of energy supply.
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Affiliation(s)
- Branislav Radović
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Nemanja Vujić
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Christina Leopold
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Stefanie Schlager
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Madeleine Goeritzer
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Jay V Patankar
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
- Center for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Melanie Korbelius
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Dagmar Kolb
- Center for Medical Research/Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria
| | - Julia Reindl
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Martin Wegscheider
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Tamara Tomin
- Institute of Pathology, Medical University of Graz, Graz, Austria
- Omics Center Graz, BioTechMed-Graz, Graz, Austria
| | - Ruth Birner-Gruenberger
- Institute of Pathology, Medical University of Graz, Graz, Austria
- Omics Center Graz, BioTechMed-Graz, Graz, Austria
| | - Matthias Schittmayer
- Institute of Pathology, Medical University of Graz, Graz, Austria
- Omics Center Graz, BioTechMed-Graz, Graz, Austria
| | - Lukas Groschner
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
- Center for Neural Circuits and Behaviour, University of Oxford, Oxford, UK
| | - Christoph Magnes
- Health, Bioanalytik und Metabolomics, Joanneum Research, Graz, Austria
| | - Clemens Diwoky
- Institute of Biomedical Engineering, Graz University of Technology, Graz, Austria
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Saša Frank
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Ernst Steyrer
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Hong Du
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Wolfgang F Graier
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
| | - Tobias Madl
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria
- Omics Center Graz, BioTechMed-Graz, Graz, Austria
- Department of Chemistry, Technical University, Munich, Germany
- Institute of Structural Biology, Helmholtz Zentrum, Munich, Germany
| | - Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010, Graz, Austria.
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16
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Is the Mouse a Good Model of Human PPARγ-Related Metabolic Diseases? Int J Mol Sci 2016; 17:ijms17081236. [PMID: 27483259 PMCID: PMC5000634 DOI: 10.3390/ijms17081236] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 07/19/2016] [Accepted: 07/21/2016] [Indexed: 12/21/2022] Open
Abstract
With the increasing number of patients affected with metabolic diseases such as type 2 diabetes, obesity, atherosclerosis and insulin resistance, academic researchers and pharmaceutical companies are eager to better understand metabolic syndrome and develop new drugs for its treatment. Many studies have focused on the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ), which plays a crucial role in adipogenesis and lipid metabolism. These studies have been able to connect this transcription factor to several human metabolic diseases. Due to obvious limitations concerning experimentation in humans, animal models—mainly mouse models—have been generated to investigate the role of PPARγ in different tissues. This review focuses on the metabolic features of human and mouse PPARγ-related diseases and the utility of the mouse as a model.
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17
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Fairbridge NA, Southall TM, Ayre DC, Komatsu Y, Raquet PI, Brown RJ, Randell E, Kovacs CS, Christian SL. Loss of CD24 in Mice Leads to Metabolic Dysfunctions and a Reduction in White Adipocyte Tissue. PLoS One 2015; 10:e0141966. [PMID: 26536476 PMCID: PMC4633231 DOI: 10.1371/journal.pone.0141966] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 10/15/2015] [Indexed: 12/21/2022] Open
Abstract
CD24 is a glycophosphatidylinositol (GPI)-linked cell surface receptor that is involved in regulating the survival or differentiation of several different cell types. CD24 has been used to identify pre-adipocytes that are able to reconstitute white adipose tissue (WAT) in vivo. Moreover, we recently found that the dynamic upregulation of CD24 in vitro during early phases of adipogenesis is necessary for mature adipocyte development. To determine the role of CD24 in adipocyte development in vivo, we evaluated the development of the inguinal and interscapular subcutaneous WAT and the epididymal visceral WAT in mice with a homozygous deletion of CD24 (CD24KO). We observed a significant decrease in WAT mass of 40% to 74% in WAT mass from both visceral and subcutaneous depots in male mice, with no significant effect in female mice, compared to wild-type (WT) sex- and age-matched controls. We also found that CD24KO mice had increased fasting glucose and free fatty acids, decreased fasting insulin, and plasma leptin. No major differences were observed in the sensitivity to insulin or glucose, or in circulating triglycerides, total cholesterol, HDL-cholesterol, or LDL-cholesterol levels between WT and CD24KO mice. Challenging the CD24KO mice with either high sucrose (35%) or high fat (45%) diets that promote increased adiposity, increased WAT mass and fasting insulin, adiponectin and leptin levels, as well as reduced the sensitivity to insulin and glucose, to the levels of WT mice on the same diets. The CD24-mediated reduction in fat pad size was due to a reduction in adipocyte cell size in all depots with no significant reduction pre-adipocyte or adipocyte cell number. Thus, we have clearly demonstrated that the global absence of CD24 affects adipocyte cell size in vivo in a sex- and diet-dependent manner, as well as causing metabolic disturbances in glucose homeostasis and free fatty acid levels.
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Affiliation(s)
- Nicholas A. Fairbridge
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Thomas M. Southall
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - D. Craig Ayre
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Yumiko Komatsu
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Paula I. Raquet
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Robert J. Brown
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Edward Randell
- Department of Laboratory Medicine, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Christopher S. Kovacs
- Division of Medicine-Endocrinology, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
| | - Sherri L. Christian
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada
- * E-mail:
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18
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Notch intracellular domain overexpression in adipocytes confers lipodystrophy in mice. Mol Metab 2015; 4:543-50. [PMID: 26137442 PMCID: PMC4481462 DOI: 10.1016/j.molmet.2015.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 04/21/2015] [Accepted: 04/24/2015] [Indexed: 02/06/2023] Open
Abstract
Objective The Notch family of intermembrane receptors is highly conserved across species and is involved in cell fate and lineage control. Previous in vitro studies have shown that Notch may inhibit adipogenesis. Here we describe the role of Notch in adipose tissue by employing an in vivo murine model which overexpresses Notch in adipose tissue. Methods Albino C57BL/6J RosaNICD/NICD::Adipoq-Cre (Ad-NICD) male mice were generated to overexpress the Notch intracellular domain (NICD) specifically in adipocytes. Male RosaNICD/NICD mice were used as controls. Mice were evaluated metabolically at the ages of 1 and 3 months by assessing body weights, serum metabolites, body composition (EchoMRI), glucose tolerance and insulin tolerance. Histological sections of adipose tissue depots as well as of liver were examined. The mRNA expression profile of genes involved in adipogenesis was analyzed by quantitative real-time PCR. Results The Ad-NICD mice were heavier with significantly lower body fat mass compared to the controls. Small amounts of white adipose tissue could be seen in the 1-month old Ad-NICD mice, but was almost absent in the 3-months old mice. The Ad-NICD mice also had higher serum levels of glucose, insulin, triglyceride and non-esterified fatty acids. These differences were more prominent in the older (3-months) than in the younger (1-month) mice. The Ad-NICD mice also showed severe insulin resistance along with a steatotic liver. Gene expression analysis in the adipose tissue depots showed a significant repression of lipogenic (Fasn, Acacb) and adipogenic pathways (C/ebpα, C/ebpβ, Pparγ2, Srebf1). Conclusions Increased Notch signaling in adipocytes in mice results in blocked expansion of white adipose tissue which leads to ectopic accumulation of lipids and insulin resistance, thus to a lipodystrophic phenotype. These results suggest that further investigation of the role of Notch signaling in adipocytes could lead to the manipulation of this pathway for therapeutic interventions in metabolic disease. Adipocyte-specific NICD (Ad-NICD) overexpression results in lipodystrophy in mice. Ad-NICD mice have increased body weight but diminished white adipose tissue. Transcriptional downregulation of adipogenesis and lipogenesis in adipose tissue of Ad-NICD mice.
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19
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Gao M, Wang M, Guo X, Qiu X, Liu L, Liao J, Liu J, Lu G, Wang Y, Liu G. Expression of seipin in adipose tissue rescues lipodystrophy, hepatic steatosis and insulin resistance in seipin null mice. Biochem Biophys Res Commun 2015; 460:143-50. [PMID: 25757906 DOI: 10.1016/j.bbrc.2015.02.147] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 02/25/2015] [Indexed: 01/17/2023]
Abstract
OBJECTIVES Gene mutations in an ER protein seipin result in congenital generalized lipodystrophy (CGL) in humans, accompanied with hepatic steatosis and insulin resistance. Seipin gene is highly expressed in the brain, testis and adipose tissue. Seipin globally deficient mice (SKO) displayed similar phenotypes as human counterparts. It has been demonstrated that adipose-specific seipin knockout mice at elder age were indistinguishable from SKO mice. Due to the large mass of adipose tissue in the body, we hypothesized that seipin in adipose tissue might be responsible for the multiple metabolism-related abnormalities in SKO mice. METHODS AND RESULTS Transgenic mice with adipose-specific expression of human seipin gene driven by aP2 promoter were generated and crossed with SKO mice to obtain adipose-specific seipin reconstitute (Seipin-RE) mice. In comparison with wild-type (WT) and SKO mice, the Seipin-RE mice exhibited normal plasma triglyceride and non-esterified fatty acids upon fasting, recovered adipose tissue mass, restored epididymal and subcutaneous fat pads morphology and partially recovered plasma leptin and adiponectin levels. Moreover, hepatic steatosis and insulin resistance was also absent in these mice. CONCLUSION Our study demonstrates that expression of seipin in adipose tissue alone could rescue dyslipidemia, lipodystrophy, hepatic steatosis and insulin resistance in SKO mice.
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Affiliation(s)
- Mingming Gao
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - Mengyu Wang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - Xin Guo
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - Xu Qiu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - Lu Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - Jiawei Liao
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - Jinjiao Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - Guotao Lu
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, 210093, China
| | - Yuhui Wang
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China
| | - George Liu
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University Health Science Center, Beijing, 100191, China.
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20
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Insulin resistance and white adipose tissue inflammation are uncoupled in energetically challenged Fsp27-deficient mice. Nat Commun 2015; 6:5949. [PMID: 25565658 PMCID: PMC4354252 DOI: 10.1038/ncomms6949] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 11/18/2014] [Indexed: 12/19/2022] Open
Abstract
Fsp27 is a lipid droplet-associated protein almost exclusively expressed in adipocytes where it facilitates unilocular lipid droplet formation. In mice, Fsp27 deficiency is associated with increased basal lipolysis, ‘browning’ of white fat and a healthy metabolic profile, whereas a patient with congenital CIDEC deficiency manifested an adverse lipodystrophic phenotype. Here we reconcile these data by showing that exposing Fsp27-null mice to a substantial energetic stress by crossing them with ob/ob mice or BATless mice, or feeding them a high-fat diet, results in hepatic steatosis and insulin resistance. We also observe a striking reduction in adipose inflammation and increase in adiponectin levels in all three models. This appears to reflect reduced activation of the inflammasome and less adipocyte death. These findings highlight the importance of Fsp27 in facilitating optimal energy storage in adipocytes and represent a rare example where adipose inflammation and hepatic insulin resistance are disassociated. Fsp27 mediates ‘fusion’ of lipid droplets in mouse adipose tissue. Here, the authors investigate the physiological consequences of loss of Fsp27 in three different mouse models of ‘energetic overload’, and observe hepatic steatosis and insulin resistance but reduced adipose tissue inflammation.
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Escande C, Nin V, Pirtskhalava T, Chini CCS, Tchkonia T, Kirkland JL, Chini EN. Deleted in breast cancer 1 limits adipose tissue fat accumulation and plays a key role in the development of metabolic syndrome phenotype. Diabetes 2015; 64:12-22. [PMID: 25053585 PMCID: PMC4274806 DOI: 10.2337/db14-0192] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is often regarded as the primary cause of metabolic syndrome. However, many lines of evidence suggest that obesity may develop as a protective mechanism against tissue damage during caloric surplus and that it is only when the maximum fat accumulation capacity is reached and fatty acid spillover occurs into to peripheral tissues that metabolic diseases develop. In this regard, identifying the molecular mechanisms that modulate adipocyte fat accumulation and fatty acid spillover is imperative. Here we identify the deleted in breast cancer 1 (DBC1) protein as a key regulator of fat storage capacity of adipocytes. We found that knockout (KO) of DBC1 facilitated fat cell differentiation and lipid accumulation and increased fat storage capacity of adipocytes in vitro and in vivo. This effect resulted in a "healthy obesity" phenotype. DBC1 KO mice fed a high-fat diet, although obese, remained insulin sensitive, had lower free fatty acid in plasma, were protected against atherosclerosis and liver steatosis, and lived longer. We propose that DBC1 is part of the molecular machinery that regulates fat storage capacity in adipocytes and participates in the "turn-off" switch that limits adipocyte fat accumulation and leads to fat spillover into peripheral tissues, leading to the deleterious effects of caloric surplus.
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Affiliation(s)
- Carlos Escande
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN Institut Pasteur Montevideo, Montevideo, Uruguay
| | - Veronica Nin
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN
| | | | - Claudia C S Chini
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN
| | | | | | - Eduardo N Chini
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN
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22
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Daquinag AC, Tseng C, Salameh A, Zhang Y, Amaya-Manzanares F, Dadbin A, Florez F, Xu Y, Tong Q, Kolonin MG. Depletion of white adipocyte progenitors induces beige adipocyte differentiation and suppresses obesity development. Cell Death Differ 2014; 22:351-63. [PMID: 25342467 PMCID: PMC4291494 DOI: 10.1038/cdd.2014.148] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 07/29/2014] [Accepted: 08/06/2014] [Indexed: 12/21/2022] Open
Abstract
Overgrowth of white adipose tissue (WAT) in obesity occurs as a result of adipocyte hypertrophy and hyperplasia. Expansion and renewal of adipocytes relies on proliferation and differentiation of white adipocyte progenitors (WAP); however, the requirement of WAP for obesity development has not been proven. Here, we investigate whether depletion of WAP can be used to prevent WAT expansion. We test this approach by using a hunter-killer peptide designed to induce apoptosis selectively in WAP. We show that targeted WAP cytoablation results in a long-term WAT growth suppression despite increased caloric intake in a mouse diet-induced obesity model. Our data indicate that WAP depletion results in a compensatory population of adipose tissue with beige adipocytes. Consistent with reported thermogenic capacity of beige adipose tissue, WAP-depleted mice display increased energy expenditure. We conclude that targeting of white adipocyte progenitors could be developed as a strategy to sustained modulation of WAT metabolic activity.
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Affiliation(s)
- A C Daquinag
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - C Tseng
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - A Salameh
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Y Zhang
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - F Amaya-Manzanares
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - A Dadbin
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - F Florez
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Y Xu
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Q Tong
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - M G Kolonin
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
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23
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Abstract
Aging is associated with increased adiposity and diminished thermogenesis, but the critical transcription factors influencing these metabolic changes late in life are poorly understood. We recently demonstrated that the winged helix factor forkhead box protein A3 (Foxa3) regulates the expansion of visceral adipose tissue in high-fat diet regimens; however, whether Foxa3 also contributes to the increase in adiposity and the decrease in brown fat activity observed during the normal aging process is currently unknown. Here we report that during aging, levels of Foxa3 are significantly and selectively up-regulated in brown and inguinal white fat depots, and that midage Foxa3-null mice have increased white fat browning and thermogenic capacity, decreased adipose tissue expansion, improved insulin sensitivity, and increased longevity. Foxa3 gain-of-function and loss-of-function studies in inguinal adipose depots demonstrated a cell-autonomous function for Foxa3 in white fat tissue browning. Furthermore, our analysis revealed that the mechanisms of Foxa3 modulation of brown fat gene programs involve the suppression of peroxisome proliferator activated receptor γ coactivtor 1 α (PGC1α) levels through interference with cAMP responsive element binding protein 1-mediated transcriptional regulation of the PGC1α promoter. Overall, our data demonstrate a role for Foxa3 in energy expenditure and in age-associated metabolic disorders.
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24
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Kim M, Neinast MD, Frank AP, Sun K, Park J, Zehr JA, Vishvanath L, Morselli E, Amelotte M, Palmer BF, Gupta RK, Scherer PE, Clegg DJ. ERα upregulates Phd3 to ameliorate HIF-1 induced fibrosis and inflammation in adipose tissue. Mol Metab 2014; 3:642-51. [PMID: 25161887 PMCID: PMC4142394 DOI: 10.1016/j.molmet.2014.05.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 05/23/2014] [Accepted: 05/28/2014] [Indexed: 01/10/2023] Open
Abstract
Hypoxia Inducible Factor 1 (HIF-1) promotes fibrosis and inflammation in adipose tissues, while estrogens and Estrogen Receptor α (ERα) have the opposite effect. Here we identify an Estrogen Response Element (ERE) in the promoter of Phd3, which is a negative regulatory enzyme of HIF-1, and we demonstrate HIF-1α is ubiquitinated following 17-β estradiol (E2)/ERα mediated Phd3 transcription. Manipulating ERα in vivo increases Phd3 transcription and reduces HIF-1 activity, while addition of PHD3 ameliorates adipose tissue fibrosis and inflammation. Our findings outline a novel regulatory relationship between E2/ERα, PHD3 and HIF-1 in adipose tissues, providing a mechanistic explanation for the protective effect of E2/ERα in adipose tissue.
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Affiliation(s)
- Min Kim
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Michael D Neinast
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Aaron P Frank
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Kai Sun
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Jiyoung Park
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA ; Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, 50 UNIST Street, Ulsan 689-798, South Korea
| | - Jordan A Zehr
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Lavanya Vishvanath
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Eugenia Morselli
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Mason Amelotte
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Biff F Palmer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Rana K Gupta
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Deborah J Clegg
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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25
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Wang QA, Scherer PE, Gupta RK. Improved methodologies for the study of adipose biology: insights gained and opportunities ahead. J Lipid Res 2014; 55:605-24. [PMID: 24532650 PMCID: PMC3966696 DOI: 10.1194/jlr.r046441] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 02/10/2014] [Indexed: 12/14/2022] Open
Abstract
Adipocyte differentiation and function have become areas of intense focus in the field of energy metabolism; however, understanding the role of specific genes in the establishment and maintenance of fat cell function can be challenging and complex. In this review, we offer practical guidelines for the study of adipocyte development and function. We discuss improved cellular and genetic systems for the study of adipose biology and highlight recent insights gained from these new approaches.
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Affiliation(s)
- Qiong A. Wang
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
| | - Philipp E. Scherer
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75287
| | - Rana K. Gupta
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
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26
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Cortés VA, Cautivo KM, Rong S, Garg A, Horton JD, Agarwal AK. Leptin ameliorates insulin resistance and hepatic steatosis in Agpat2-/- lipodystrophic mice independent of hepatocyte leptin receptors. J Lipid Res 2013; 55:276-88. [PMID: 24293639 DOI: 10.1194/jlr.m045799] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Leptin is essential for energy homeostasis and regulation of food intake. Patients with congenital generalized lipodystrophy (CGL) due to mutations in 1-acylglycerol-3-phosphate-O-acyltransferase 2 (AGPAT2) and the CGL murine model (Agpat2(-/-) mice) both have severe insulin resistance, diabetes mellitus, hepatic steatosis, and low plasma leptin levels. In this study, we show that continuous leptin treatment of Agpat2(-/-) mice for 28 days reduced plasma insulin and glucose levels and normalized hepatic steatosis and hypertriglyceridemia. Leptin also partially, but significantly, reversed the low plasma thyroxine and high corticosterone levels found in Agpat2(-/-) mice. Levels of carbohydrate response element binding protein (ChREBP) were reduced, whereas lipogenic gene expression were increased in the livers of Agpat2(-/-) mice, suggesting that deregulated ChREBP contributed to the development of fatty livers in these mice and that this transcription factor is a target of leptin's beneficial metabolic action. Leptin administration did not change hepatic fatty acid oxidation enzymes mRNA levels in Agpat2(-/-) mice. The selective deletion of leptin receptors only in hepatocytes did not prevent the positive metabolic actions of leptin in Agpat2(-/-) mice, supporting the notion that the majority of metabolic actions of leptin are dependent on its action in nonhepatocyte cells and/or the central nervous system.
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Affiliation(s)
- Víctor A Cortés
- Department of Molecular Genetics, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
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27
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Kawakami T, Nishiyama K, Kadota Y, Sato M, Inoue M, Suzuki S. Cadmium modulates adipocyte functions in metallothionein-null mice. Toxicol Appl Pharmacol 2013; 272:625-36. [PMID: 23921151 DOI: 10.1016/j.taap.2013.07.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/22/2013] [Accepted: 07/24/2013] [Indexed: 01/01/2023]
Abstract
Our previous study has demonstrated that exposure to cadmium (Cd), a toxic heavy metal, causes a reduction of adipocyte size and the modulation of adipokine expression. To further investigate the significance of the Cd action, we studied the effect of Cd on the white adipose tissue (WAT) of metallothionein null (MT(-/-)) mice, which cannot form atoxic Cd-MT complexes and are used for evaluating Cd as free ions, and wild type (MT(+/+)) mice. Cd administration more significantly reduced the adipocyte size of MT(-/-) mice than that of MT(+/+) mice. Cd exposure also induced macrophage recruitment to WAT with an increase in the expression level of Ccl2 (MCP-1) in the MT(-/-) mice. The in vitro exposure of Cd to adipocytes induce triglyceride release into culture medium, decrease in the expression levels of genes involved in fatty acid synthesis and lipid hydrolysis at 24 h, and at 48 h increase in phosphorylation of the lipid-droplet-associated protein perilipin, which facilitates the degradation of stored lipids in adipocytes. Therefore, the reduction in adipocyte size by Cd may arise from an imbalance between lipid synthesis and lipolysis. In addition, the expression levels of leptin, adiponectin and resistin decreased in adipocytes. Taken together, exposure to Cd may induce unusually small adipocytes and modulate the expression of adipokines differently from the case of physiologically small adipocytes, and may accelerate the risk of developing insulin resistance and type 2 diabetes.
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Affiliation(s)
- Takashige Kawakami
- Faculty of Pharmaceutical Science, Tokushima Bunri University, 180 Yamashiro-cho, Tokushima 770-8514, Japan
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28
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Jung EM, An BS, Kim YK, Jeong YH, Hwang WS, Jeung EB. Generation of porcine fibroblasts overexpressing 11β-HSD1 with adipose tissue-specific aP2 promoter as a porcine model of metabolic syndrome. Mol Med Rep 2013; 8:751-6. [PMID: 23864280 DOI: 10.3892/mmr.2013.1592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 06/26/2013] [Indexed: 11/06/2022] Open
Abstract
Metabolic syndrome arises from a combination of disorders that increase the risk of cardiovascular disease and diabetes. In previous studies, it was observed that overexpression of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) induced obesity and the insulin resistance that accompanies metabolic syndrome in rodent adipose tissue. Based on these observations, it was hypothesized that overexpression of 11β-HSD1 may be suitable for the generation of a porcine model of metabolic syndrome. It was evaluated that promoter activities of the porcine adipose fatty acid-binding protein (aP2) gene generates adipose tissue-specific 11β-HSD1 expression. In adipose tissue, the maximum promoter activity (-2,826 to +51 nt) of aP2 was 200-fold higher than that of a promoterless construct. In addition, 11β-HSD1 transcriptional levels were significantly increased following the introduction of the aP2 promoter into 3T3‑L1 adipocytes. These observations indicate that the aP2 promoter may facilitate 11β-HSD1 overexpression in porcine adipose tissue. Transgenic fibroblasts were generated containing 11β-HSD1 cDNA controlled by the aP2 promoter with two screening markers, green fluorescence protein and a neomycin-resistance gene. It was hypothesized that transgenic fibroblasts may be useful for generating a porcine model of metabolic syndrome.
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Affiliation(s)
- Eui-Man Jung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungcheongbuk‑do 361‑763, Republic of Korea
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Abstract
White adipose tissue (WAT) is not only a lipogenic and fat storage tissue but also an important endocrine organ that regulates energy homeostasis, lipid metabolism, appetite, fertility, and immune and stress responses. Liver kinase B1 (LKB1), a tumor suppressor, is a key regulator in energy metabolism. However, the role of LKB1 in adipogenesis is unknown. The current study aimed to determine the contributions of LKB1 to adipogenesis in vivo. Using the Fabp4-Cre/loxP system, we generated adipose tissue-specific LKB1 knockout (LKB1(ad-/-)) mice. LKB1(ad-/-) mice exhibited a reduced amount of WAT, postnatal growth retardation, and early death before weaning. Further, LKB1 deletion markedly reduced the levels of insulin receptor substrate 1 (IRS1), peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, and phosphorylated AMP-activated protein kinase (AMPK). Consistent with these results, overexpression of constitutively active AMPK partially ablated IRS1 degradation in LKB1-deficient cells. LKB1 deletion increased the levels of F-box/WD repeat-containing protein (Fbw) 8, the IRS1 ubiquitination E3 ligase. Silencing of Fbw8 increased IRS1 levels. Finally, promoter analysis and DNA chromatin immunoprecipitation analysis identified three sterol regulatory element (SRE) sites in the Fbw8 promoter, where SRE-binding protein 1c binds and induces the expression of Fbw8. Taken together, these data indicate that LKB1 controls IRS1-dependent adipogenesis via AMPK in WAT.
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Affiliation(s)
- Wencheng Zhang
- Section of Molecule Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Qilong Wang
- Section of Molecule Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Ping Song
- Section of Molecule Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Ming-Hui Zou
- Section of Molecule Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Corresponding author: Ming-Hui Zou,
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30
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Turer AT, Hill JA, Elmquist JK, Scherer PE. Adipose tissue biology and cardiomyopathy: translational implications. Circ Res 2013; 111:1565-77. [PMID: 23223931 DOI: 10.1161/circresaha.111.262493] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It is epidemiologically established that obesity is frequently associated with the metabolic syndrome and poses an increased risk for the development of type 2 diabetes mellitus and cardiovascular disease. The molecular links that connect the phenomenon of obesity, per se, with insulin resistance and cardiovascular disease are still not fully elucidated. It is increasingly apparent that fully functional adipose tissue can be cardioprotective by reducing lipotoxic effects in other peripheral tissues and by maintaining a healthy balance of critical adipokines, thereby allowing the heart to maintain its full metabolic flexibility. The present review highlights both basic and clinical findings that emphasize the complex interplay of adipose tissue physiology and adipokine-mediated effects on the heart exerted by either direct effects on cardiac myocytes or indirect actions via central mechanisms through sympathetic outflow to the heart.
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Affiliation(s)
- Aslan T Turer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
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31
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Guo T, Bond ND, Jou W, Gavrilova O, Portas J, McPherron AC. Myostatin inhibition prevents diabetes and hyperphagia in a mouse model of lipodystrophy. Diabetes 2012; 61:2414-23. [PMID: 22596054 PMCID: PMC3447905 DOI: 10.2337/db11-0915] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Lipodystrophies are characterized by a loss of white adipose tissue, which causes ectopic lipid deposition, peripheral insulin resistance, reduced adipokine levels, and increased food intake (hyperphagia). The growth factor myostatin (MSTN) negatively regulates skeletal muscle growth, and mice with MSTN inhibition have reduced adiposity and improved insulin sensitivity. MSTN inhibition may therefore be efficacious in ameliorating diabetes. To test this hypothesis, we inhibited MSTN signaling in a diabetic model of generalized lipodystrophy to analyze its effects on glucose metabolism separate from effects on adipose mass. A-ZIP/F1 lipodystrophic mice were crossed to mice expressing a dominant-negative MSTN receptor (activin receptor type IIB) in muscle. MSTN inhibition in A-ZIP/F1 mice reduced blood glucose, serum insulin, triglyceride levels, and the rate of triglyceride synthesis, and improved insulin sensitivity. Unexpectedly, hyperphagia was normalized by MSTN inhibition in muscle. Blood glucose and hyperphagia were reduced in double mutants independent of the adipokine leptin. These results show that the effect of MSTN inhibition on insulin sensitivity is not secondary to an effect on adipose mass and that MSTN inhibition may be an effective treatment for diabetes. These results further suggest that muscle may play a heretofore unappreciated role in regulating food intake.
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Affiliation(s)
- Tingqing Guo
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Nichole D. Bond
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - William Jou
- Mouse Metabolic Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Oksana Gavrilova
- Mouse Metabolic Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Jennifer Portas
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Alexandra C. McPherron
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
- Corresponding author: Alexandra C. McPherron,
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Interleukin-7 regulates adipose tissue mass and insulin sensitivity in high-fat diet-fed mice through lymphocyte-dependent and independent mechanisms. PLoS One 2012; 7:e40351. [PMID: 22768283 PMCID: PMC3386973 DOI: 10.1371/journal.pone.0040351] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 06/07/2012] [Indexed: 12/21/2022] Open
Abstract
Although interleukin (IL)-7 is mostly known as a key regulator of lymphocyte homeostasis, we recently demonstrated that it also contributes to body weight regulation through a hypothalamic control. Previous studies have shown that IL-7 is produced by the human obese white adipose tissue (WAT) yet its potential role on WAT development and function in obesity remains unknown. Here, we first show that transgenic mice overexpressing IL-7 have reduced adipose tissue mass associated with glucose and insulin resistance. Moreover, in the high-fat diet (HFD)-induced obesity model, a single administration of IL-7 to C57BL/6 mice is sufficient to prevent HFD-induced WAT mass increase and glucose intolerance. This metabolic protective effect is accompanied by a significant decreased inflammation in WAT. In lymphocyte-deficient HFD-fed SCID mice, IL-7 injection still protects from WAT mass gain. However, IL-7-triggered resistance against WAT inflammation and glucose intolerance is lost in SCID mice. These results suggest that IL-7 regulates adipose tissue mass through a lymphocyte-independent mechanism while its protective role on glucose homeostasis would be relayed by immune cells that participate to WAT inflammation. Our observations establish a key role for IL-7 in the complex mechanisms by which immune mediators modulate metabolic functions.
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33
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Altered mitochondrial function and metabolic inflexibility associated with loss of caveolin-1. Cell Metab 2012; 15:171-85. [PMID: 22326219 PMCID: PMC3278712 DOI: 10.1016/j.cmet.2012.01.004] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 07/30/2011] [Accepted: 01/06/2012] [Indexed: 11/23/2022]
Abstract
Caveolin-1 is a major structural component of raft structures within the plasma membrane and has been implicated as a regulator of cellular signal transduction with prominent expression in adipocytes. Here, we embarked on a comprehensive characterization of the metabolic pathways dysregulated in caveolin-1 null mice. We found that these mice display decreased circulating levels of total and high molecular weight adiponectin and a reduced ability to change substrate use in response to feeding/fasting conditions. Caveolin-1 null mice are extremely lean but retain muscle mass despite lipodystrophy and massive metabolic dysfunction. Hepatic gluconeogenesis is chronically elevated, while hepatic steatosis is reduced. Our data suggest that the complex phenotype of the caveolin-1 null mouse is caused by altered metabolic and mitochondrial function in adipose tissue with a subsequent compensatory response driven mostly by the liver. This mouse model highlights the central contributions of adipose tissue for system-wide preservation of metabolic flexibility.
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34
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Tanowitz HB, Jelicks LA, Machado FS, Esper L, Qi X, Desruisseaux MS, Chua SC, Scherer PE, Nagajyothi F. Adipose tissue, diabetes and Chagas disease. ADVANCES IN PARASITOLOGY 2011; 76:235-50. [PMID: 21884894 DOI: 10.1016/b978-0-12-385895-5.00010-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Adipose tissue is the largest endocrine organ in the body and is composed primarily of adipocytes (fat cells) but also contains fibroblasts, endothelial cells, smooth muscle cells, macrophages and lymphocytes. Adipose tissue and the adipocyte are important in the regulation of energy metabolism and of the immune response. Adipocytes also synthesize adipokines such as adiponectin which is important in the regulation of insulin sensitivity and inflammation. Infection of mice with Trypanosoma cruzi results in an upregulation of inflammation in adipose tissue that begins during the acute phase of infection and persists into the chronic phase. The adipocyte is both a target of infection and a reservoir for the parasite during the chronic phase from which recrudescence of the infection may occur during periods of immunosuppression.
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Affiliation(s)
- Herbert B Tanowitz
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, USA
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Mudhasani R, Puri V, Hoover K, Czech MP, Imbalzano AN, Jones SN. Dicer is required for the formation of white but not brown adipose tissue. J Cell Physiol 2011; 226:1399-406. [PMID: 20945399 DOI: 10.1002/jcp.22475] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dicer, an enzyme involved in microRNA maturation, is required for proper embryo gastrulation and tissue morphogenesis during mammalian development. Using primary cultures of fibroblasts and pre-adipocytes, we have previously shown that Dicer is essential for early stages of adipogenic cell differentiation. In this study, we have utilized Dicer-conditional mice to explore a role for Dicer and microRNA biogenesis in the terminal differentiation of adipocytes in vivo and in the formation of white and brown adipose tissue. Deletion of Dicer in differentiated adipocytes in Dicer-conditional, aP2-Cre transgenic mice reduced the level of various adipogenic-associated transcripts and inhibited lipogenesis in white adipocytes, resulting in a severe depletion of white adipose tissue in mice. In contrast, Dicer was not required in vivo for lipogenesis in brown adipose or for brown fat formation. However, Dicer deletion in brown adipose did decrease the expression of genes involved in thermoregulation. The results of our study provide genetic evidence of a role for microRNA molecules in regulating adipogenesis and reveal distinct requirements for Dicer in the formation of white and brown adipose tissue.
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Affiliation(s)
- Rajini Mudhasani
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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Vogel P, Read R, Hansen G, Wingert J, Dacosta CM, Buhring LM, Shadoan M. Pathology of congenital generalized lipodystrophy in Agpat2-/- mice. Vet Pathol 2010; 48:642-54. [PMID: 21051554 DOI: 10.1177/0300985810383870] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Congenital generalized lipodystrophy (CGL) comprises a heterogeneous group of rare diseases associated with partial or total loss of adipose tissue. Of these, autosomal recessive Berardinelli-Seip congenital lipodystrophy (BSCL) is characterized by the absence of metabolically active subcutaneous and visceral adipose tissues. Metabolic abnormalities associated with lipodystrophy include insulin resistance, hypertriglyceridemia, hepatic steatosis, and diabetes. One form of BSCL has been linked to genetic mutations affecting the lipid biosynthetic enzyme 1-acyl-sn-glycerol 3-phosphate O-acyltransferase 2 (AGPAT2), which is highly expressed in adipose tissue. Precisely how AGPAT2 deficiency causes lipodystrophy remains unresolved, but possible mechanisms include impaired lipogenesis (triglyceride synthesis and storage), blocked adipogenesis (differentiation of preadipocytes to adipocytes), or apoptosis/necrosis of adipocytes. Agpat2(-/-) mice share important pathophysiologic features of CGL previously reported in humans. However, the small white adipose tissue (WAT) depots consisting largely of amoeboid adipocytes with microvesiculated basophilic cytoplasm showed that adipogenesis with deficient lipogenesis was present in all usual locations. Although well-defined lobules of brown adipose tissue (BAT) were present, massive necrosis resulted in early ablation of BAT. Although necrotic or apoptotic adipocytes were not detected in WAT of 10-day-old Agpat2(-/-), the absence of adipocytes in aged mice indicates that these cells must undergo necrosis/apoptosis at some point. Another significant finding in aged lipodystrophic mice was massive pancreatic islet hypertrophy in the face of chronic hyperglycemia, which suggests that glucotoxicity is insufficient by itself to cause β-cell loss and that adipocyte-derived factors help regulate total β-cell mass.
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Affiliation(s)
- P Vogel
- Lexicon Pharmaceuticals, Inc, Pathology Department, The Woodlands, TX 77381-1160, USA.
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Nagajyothi F, Desruisseaux MS, Weiss LM, Chua S, Albanese C, Machado FS, Esper L, Lisanti MP, Teixeira MM, Scherer PE, Tanowitz HB. Chagas disease, adipose tissue and the metabolic syndrome. Mem Inst Oswaldo Cruz 2010; 104 Suppl 1:219-25. [PMID: 19753477 DOI: 10.1590/s0074-02762009000900028] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Accepted: 05/22/2009] [Indexed: 01/28/2023] Open
Abstract
Trypanosoma cruzi infection of the adipose tissue of mice triggers the local expression of inflammatory mediators and a reduction in the expression of the adipokine adiponectin. T. cruzi can be detected in adipose tissue by PCR 300 days post-infection. Infection of cultured adipocytes results in increased expression of cytokines and chemokines and a reduction in the expression of adiponectin and the peroxisome proliferator-activated receptor gamma, both of which are negative regulators of inflammation. Infection also results in the upregulation of cyclin D1, the Notch pathway, and extracellular signal-regulated kinase and a reduction in the expression of caveolin-1. Thus, T. cruzi infection of cultured adipocytes leads to an upregulation of the inflammatory process. Since adiponectin null mice have a cardiomyopathic phenotype, it is possible that the reduction in adiponectin contributes to the pathogenesis of chagasic cardiomyopathy. Adipose tissue may serve as a reservoir for T. cruzi from which parasites can become reactivated during periods of immunosuppression. T. cruzi infection of mice often results in hypoglycemia. In contrast, hyperglycemia as observed in diabetes results in increased parasitemia and mortality. Adipose tissue is an important target tissue of T. cruzi and the infection of this tissue is associated with a profound impact on systemic metabolism, increasing the risk of metabolic syndrome.
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Affiliation(s)
- Fnu Nagajyothi
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Abstract
Insulin resistance is a major factor in the pathogenesis of type 2 diabetes and underpins the strong association between obesity and diabetes. Paradoxically, the metabolic consequences of having 'too much' fat (obesity) are remarkably similar to those of having 'too little' fat (lipodystrophy): a finding that has generated considerable interest in a rare disease. In both cases, excess energy accumulates as lipid in ectopic sites such as the liver (fatty liver) and skeletal muscle, where it plays a central role in the pathogenesis of insulin resistance, dyslipidemia and type 2 diabetes. Human lipodystrophies are characterised by a total or partial deficiency of body fat, and may be inherited or acquired in origin. Genetically engineered mice with generalised lipodystrophy manifest many of the features of the human disorder, including hyperphagia, fatty liver, hypertriglyceridaemia, insulin resistance and type 2 diabetes, providing a useful tractable model of the human disorder. Partial lipodystrophy, which causes similar, albeit milder, metabolic problems in humans has been more difficult to mimic in the mouse. This review discusses key translational studies in mice with generalised lipodystrophy, including fat transplantation and the use of recombinant leptin replacement therapy. These studies have been instrumental in advancing our understanding of the underlying molecular pathogenesis of ectopic lipid accumulation and insulin resistance, and have prompted the initiation and subsequent adoption of leptin replacement therapy in human lipodystrophies. This review also considers the possible reasons for the apparent difficulties in generating mouse models of partial lipodystrophy, such as interspecies differences in the distribution of fat depots and the apparent lack of sexual dimorphism in fat mass and distribution in mice compared with the dramatic differences present in adult humans.
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Affiliation(s)
- David B Savage
- Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
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Hall AM, Brunt EM, Chen Z, Viswakarma N, Reddy JK, Wolins NE, Finck BN. Dynamic and differential regulation of proteins that coat lipid droplets in fatty liver dystrophic mice. J Lipid Res 2009; 51:554-63. [PMID: 19749180 DOI: 10.1194/jlr.m000976] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Lipid droplet proteins (LDPs) coat the surface of triglyceride-rich lipid droplets and regulate their formation and lipolysis. We profiled hepatic LDP expression in fatty liver dystrophic (fld) mice, a unique model of neonatal hepatic steatosis that predictably resolves between postnatal day 14 (P14) and P17. Western blotting revealed that perilipin-2/ADRP and perilipin-5/OXPAT were markedly increased in steatotic fld liver but returned to normal by P17. However, the changes in perilipin-2 and perilipin-5 protein content in fld mice were exaggerated compared with relatively modest increases in corresponding mRNAs encoding these proteins, a phenomenon likely mediated by increased protein stability. Conversely, cell death-inducing DFFA-like effector (Cide) family genes were strongly induced at the level of mRNA expression in steatotic fld mouse liver. Surprisingly, levels of peroxisome proliferator-activated receptor gamma, which is known to regulate Cide expression, were unchanged in fld mice. However, sterol-regulatory element binding protein 1 (SREBP-1) was activated in fld liver and CideA was revealed as a new direct target gene of SREBP-1. In summary, LDP content is markedly increased in liver of fld mice. However, whereas perilipin-2 and perilipin-5 levels are primarily regulated posttranslationally, Cide family mRNA expression is induced, suggesting that these families of LDP are controlled at different regulatory checkpoints.
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Affiliation(s)
- Angela M Hall
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
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Perspectives on adipose tissue, chagas disease and implications for the metabolic syndrome. Interdiscip Perspect Infect Dis 2009; 2009:824324. [PMID: 19644556 PMCID: PMC2715900 DOI: 10.1155/2009/824324] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 05/27/2009] [Indexed: 01/07/2023] Open
Abstract
The contribution of adipose tissue an
autocrine and endocrine organ in the
pathogenesis of infectious disease and metabolic
syndrome is gaining attention. Adipose tissue
and adipocytes
are one of the major targets of T. cruzi infection. Parasites are detected 300 days postinfection in adipose tissue. Infection of adipose tissue and cultured adipocytes triggered local
expression of inflammatory mediators resulting in the upregulation of cytokine and chemokine
levels. Adipose tissue obtained from infected mice display an increased infiltration of
inflammatory cells. Adiponectin, an adipocyte specific protein, which exerts antiinflammatory
effects, is reduced during the acute phase of infection. The antiinflammatory regulator
peroxisome proliferator activated receptor-γ (PPAR-γ) is downregulated in infected cultured
adipocytes and adipose tissue. T. cruzi infection is associated with an upregulation of signaling
pathways such as MAPKs, Notch and cyclin D, and reduced caveolin-1 expression.
Adiponectin null mice have a cardiomyopathy and thus we speculate that the T. cruzi-induced
reduction in adiponectin contributes to the T. cruzi-induced cardiomyopathy. While T. cruzi infection causes hypoglycemia which correlates with mortality, hyperglycemia is associated
with increased parasitemia and mortality. The T. cruzi-induced increase in macrophages in
adipose tissue taken together with the reduction in adiponectin and the associated
cardiomyopathy is reminiscent of the metabolic syndrome.
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Groh S, Zong H, Goddeeris MM, Lebakken CS, Venzke D, Pessin JE, Campbell KP. Sarcoglycan complex: implications for metabolic defects in muscular dystrophies. J Biol Chem 2009; 284:19178-82. [PMID: 19494113 PMCID: PMC2740540 DOI: 10.1074/jbc.c109.010728] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The sarcoglycans are known as an integral subcomplex of the dystrophin glycoprotein complex, the function of which is best characterized in skeletal muscle in relation to muscular dystrophies. Here we demonstrate that the white adipocytes, which share a common precursor with the myocytes, express a cell-specific sarcoglycan complex containing β-, δ-, and ϵ-sarcoglycan. In addition, the adipose sarcoglycan complex associates with sarcospan and laminin binding dystroglycan. Using multiple sarcoglycan null mouse models, we show that loss of α-sarcoglycan has no consequence on the expression of the adipocyte sarcoglycan complex. However, loss of β- or δ-sarcoglycan leads to a concomitant loss of the sarcoglycan complex as well as sarcospan and a dramatic reduction in dystroglycan in adipocytes. We further demonstrate that β-sarcoglycan null mice, which lack the sarcoglycan complex in adipose tissue and skeletal muscle, are glucose-intolerant and exhibit whole body insulin resistance specifically due to impaired insulin-stimulated glucose uptake in skeletal muscles. Thus, our data demonstrate a novel function of the sarcoglycan complex in whole body glucose homeostasis and skeletal muscle metabolism, suggesting that the impairment of the skeletal muscle metabolism influences the pathogenesis of muscular dystrophy.
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Affiliation(s)
- Séverine Groh
- Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1101, USA
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Zhou J, Lei W, Shen L, Luo HS, Shen ZX. Primary study of leptin and human hepatocellular carcinoma in vitro. World J Gastroenterol 2008; 14:2900-4. [PMID: 18473418 PMCID: PMC2710735 DOI: 10.3748/wjg.14.2900] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIM: To investigate the expression level and effects of leptin in human hepatocellular carcinoma cells in vitro and to explore the correlation between them.
METHODS: Human hepatocellular carcinoma cell line HepG2 was cultured in vitro, and (the expression level) mRNA of leptin and leptin receptors in HepG2 were assessed using reverse transcription polymerase chain reaction (RT-PCR). Effects of different concentrations of leptin (50 ng/mL, 100 ng/mL, 200 ng/mL) on HepG2 were detected with colorimetric assay by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) after incubation periods of 24 h, 48 h, and 72 h. Flow cytometry was performed to assess cell cycle progression of different concentrations of leptin as stated above after each 24 h incubation period.
RESULTS: mRNA of leptin and leptin receptors (including short and long isoforms) were expressed in HepG2. The 72 h incubation of leptin at different concentrations (50 ng/mL, 100 ng/mL, 200 ng/mL) promoted proliferation of HepG2 in a concentration- and time-dependent manner. The experimental group shows significant statistical differences when compared to the controlled group which contained 0 ng/mL of leptin. As the concentration of leptin increases, significant fewer cells were detected in G0-G1 phase and more cells in S and G2-M phases.
CONCLUSION: Leptin and leptin receptor are simultaneously expressed in human hepatocellular carcinoma cell line HepG2. Addition of leptin (0 ng/mL-200 ng/mL) in 72 h periods indicated there is a concentration- and time-dependent correlation in the stimulation of HepG2 cell proliferation. The effect of proliferation by leptin is due to promotion of DNA synthesis and enhancement of mitotic activity. The relationship between leptin and human hepatocellular carcinoma cells might indicate that adipokine could be associated with the progression of human hepatocellular carcinoma.
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