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Wang F, Huynh PM, An YA. Mitochondrial Function and Dysfunction in White Adipocytes and Therapeutic Implications. Compr Physiol 2024; 14:5581-5640. [PMID: 39382163 DOI: 10.1002/cphy.c230009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2024]
Abstract
For a long time, white adipocytes were thought to function as lipid storages due to the sizeable unilocular lipid droplet that occupies most of their space. However, recent discoveries have highlighted the critical role of white adipocytes in maintaining energy homeostasis and contributing to obesity and related metabolic diseases. These physiological and pathological functions depend heavily on the mitochondria that reside in white adipocytes. This article aims to provide an up-to-date overview of the recent research on the function and dysfunction of white adipocyte mitochondria. After briefly summarizing the fundamental aspects of mitochondrial biology, the article describes the protective role of functional mitochondria in white adipocyte and white adipose tissue health and various roles of dysfunctional mitochondria in unhealthy white adipocytes and obesity. Finally, the article emphasizes the importance of enhancing mitochondrial quantity and quality as a therapeutic avenue to correct mitochondrial dysfunction, promote white adipocyte browning, and ultimately improve obesity and its associated metabolic diseases. © 2024 American Physiological Society. Compr Physiol 14:5581-5640, 2024.
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Affiliation(s)
- Fenfen Wang
- Department of Anesthesiology, Critical Care, and Pain Medicine, Center for Perioperative Medicine, McGovern Medical School, UT Health Science Center at Houston, Houston, Texas, USA
| | - Phu M Huynh
- Department of Anesthesiology, Critical Care, and Pain Medicine, Center for Perioperative Medicine, McGovern Medical School, UT Health Science Center at Houston, Houston, Texas, USA
| | - Yu A An
- Department of Anesthesiology, Critical Care, and Pain Medicine, Center for Perioperative Medicine, McGovern Medical School, UT Health Science Center at Houston, Houston, Texas, USA
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, McGovern Medical School, UT Health Science Center at Houston, Houston, Texas, USA
- Department of Biochemistry and Molecular Biology, McGovern Medical School, UT Health Science Center at Houston, Houston, Texas, USA
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2
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Fryklund C, Morén B, Shah S, Grossi M, Degerman E, Matthaeus C, Stenkula KG. EH Domain-Containing 2 Deficiency Restricts Adipose Tissue Expansion and Impairs Lipolysis in Primary Inguinal Adipocytes. Front Physiol 2021; 12:740666. [PMID: 34630160 PMCID: PMC8497890 DOI: 10.3389/fphys.2021.740666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/25/2021] [Indexed: 11/21/2022] Open
Abstract
Lipid uptake can be facilitated via caveolae, specific plasma membrane invaginations abundantly expressed in adipocytes. The dynamin-related protein EH domain-containing 2 (EHD2) stabilizes caveolae at the cell surface. Here, we have examined the importance of EHD2 for lipid handling using primary adipocytes isolated from EHD2 knockout (Ehd2−/−) C57BL6/N mice. Following high-fat diet (HFD) feeding, we found a clear impairment of epididymal, but not inguinal, adipose tissue expansion in Ehd2−/− compared with Ehd2+/+ (WT) mice. Cell size distribution analysis revealed that Ehd2−/− mice had a lower proportion of small adipocytes, and an accumulation of medium-sized adipocytes in both epididymal and inguinal adipose tissue. Further, PPARγ activity, FABP4 and caveolin-1 expression were decreased in adipocytes isolated from Ehd2−/− mice. Inguinal adipocytes isolated from Ehd2−/− mice displayed reduced lipolysis in response to beta adrenergic receptor agonist, which was associated with reduced phosphorylation of perilipin-1 and hormone sensitive lipase (HSL). This impairment could not be rescued using a cAMP analog, indicating that impaired lipolysis in Ehd2−/− primary adipocytes likely occurs at the level of, or downstream of, protein kinase A (PKA). Altogether, these findings pinpoint the importance of EHD2 for maintained intracellular lipid metabolism, and emphasize differences in mechanisms regulating lipid handling in various adipose-tissue depots.
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Affiliation(s)
- Claes Fryklund
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Björn Morén
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Shrenika Shah
- School of Biomedical, Nutritional and Sport Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mario Grossi
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Eva Degerman
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Claudia Matthaeus
- National Heart, Lung and Blood Institute, NIH, Bethesda, MD, United States
| | - Karin G Stenkula
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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3
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Abstract
Adipose tissue depots in distinct anatomical locations mediate key aspects of metabolism, including energy storage, nutrient release, and thermogenesis. Although adipocytes make up more than 90% of adipose tissue volume, they represent less than 50% of its cellular content. Here, I review recent advances in genetic lineage tracing and transcriptomics that reveal the identities of the heterogeneous cell populations constituting mouse and human adipose tissues. In addition to mature adipocytes and their progenitors, these include endothelial and various immune cell types that together orchestrate adipose tissue development and functions. One salient finding is the identification of progenitor subtypes that can modulate adipogenic capacity through paracrine mechanisms. Another is the description of fate trajectories of monocyte/macrophages, which can respond maladaptively to nutritional and thermogenic stimuli, leading to metabolic disease. These studies have generated an extraordinary source of publicly available data that can be leveraged to explore commonalities and differences among experimental models, providing new insights into adipose tissues and their role in metabolic disease.
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Affiliation(s)
- Silvia Corvera
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA;
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4
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Honkala SM, Motiani P, Kivelä R, Hemanthakumar KA, Tolvanen E, Motiani KK, Eskelinen JJ, Virtanen KA, Kemppainen J, Heiskanen MA, Löyttyniemi E, Nuutila P, Kalliokoski KK, Hannukainen JC. Exercise training improves adipose tissue metabolism and vasculature regardless of baseline glucose tolerance and sex. BMJ Open Diabetes Res Care 2020; 8:e000830. [PMID: 32816872 PMCID: PMC7437884 DOI: 10.1136/bmjdrc-2019-000830] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 05/08/2020] [Accepted: 06/10/2020] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION We investigated the effects of a supervised progressive sprint interval training (SIT) and moderate-intensity continuous training (MICT) on adipocyte morphology and adipose tissue metabolism and function; we also tested whether the responses were similar regardless of baseline glucose tolerance and sex. RESEARCH DESIGN AND METHODS 26 insulin-resistant (IR) and 28 healthy participants were randomized into 2-week-long SIT (4-6×30 s at maximum effort) and MICT (40-60 min at 60% of maximal aerobic capacity (VO2peak)). Insulin-stimulated glucose uptake and fasting-free fatty acid uptake in visceral adipose tissue (VAT), abdominal and femoral subcutaneous adipose tissues (SATs) were quantified with positron emission tomography. Abdominal SAT biopsies were collected to determine adipocyte morphology, gene expression markers of lipolysis, glucose and lipid metabolism and inflammation. RESULTS Training increased glucose uptake in VAT (p<0.001) and femoral SAT (p<0.001) and decreased fatty acid uptake in VAT (p=0.01) irrespective of baseline glucose tolerance and sex. In IR participants, training increased adipose tissue vasculature and decreased CD36 and ANGPTL4 gene expression in abdominal SAT. SIT was superior in increasing VO2peak and VAT glucose uptake in the IR group, whereas MICT reduced VAT fatty acid uptake more than SIT. CONCLUSIONS Short-term training improves adipose tissue metabolism both in healthy and IR participants independently of the sex. Adipose tissue angiogenesis and gene expression was only significantly affected in IR participants.
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Affiliation(s)
| | | | - Riikka Kivelä
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | | | - Erik Tolvanen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | | | | | | | | | | | | | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland
- Turku PET Centre, Turku University Hospital, Turku, Finland
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5
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Poklukar K, Čandek-Potokar M, Batorek Lukač N, Tomažin U, Škrlep M. Lipid Deposition and Metabolism in Local and Modern Pig Breeds: A Review. Animals (Basel) 2020; 10:E424. [PMID: 32138208 PMCID: PMC7142902 DOI: 10.3390/ani10030424] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 12/25/2022] Open
Abstract
Modern pig breeds, which have been genetically improved to achieve fast growth and a lean meat deposition, differ from local pig breeds with respect to fat deposition, fat specific metabolic characteristics and various other properties. The present review aimed to elucidate the mechanisms underlying the differences between fatty local and modern lean pig breeds in adipose tissue deposition and lipid metabolism, taking into consideration morphological, cellular, biochemical, transcriptomic and proteomic perspectives. Compared to modern breeds, local pig breeds accumulate larger amounts of fat, which generally contains more monounsaturated and saturated fatty acids; they exhibit a higher adipocyte size and higher activity of lipogenic enzymes. Studies using transcriptomic and proteomic approaches highlighted several processes like immune response, fatty-acid turn-over, oxidoreductase activity, mitochondrial function, etc. which differ between local and modern pig breeds.
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Affiliation(s)
- Klavdija Poklukar
- Agricultural Institute of Slovenia, Ljubljana SI-1000, Slovenia; (K.P.); (M.Č.-P.); (N.B.L.); (U.T.)
| | - Marjeta Čandek-Potokar
- Agricultural Institute of Slovenia, Ljubljana SI-1000, Slovenia; (K.P.); (M.Č.-P.); (N.B.L.); (U.T.)
- University of Maribor, Faculty of Agriculture and Life Sciences, Hoče SI-2311, Slovenia
| | - Nina Batorek Lukač
- Agricultural Institute of Slovenia, Ljubljana SI-1000, Slovenia; (K.P.); (M.Č.-P.); (N.B.L.); (U.T.)
| | - Urška Tomažin
- Agricultural Institute of Slovenia, Ljubljana SI-1000, Slovenia; (K.P.); (M.Č.-P.); (N.B.L.); (U.T.)
| | - Martin Škrlep
- Agricultural Institute of Slovenia, Ljubljana SI-1000, Slovenia; (K.P.); (M.Č.-P.); (N.B.L.); (U.T.)
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6
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Kopchick JJ, Berryman DE, Puri V, Lee KY, Jorgensen JOL. The effects of growth hormone on adipose tissue: old observations, new mechanisms. Nat Rev Endocrinol 2020; 16:135-146. [PMID: 31780780 PMCID: PMC7180987 DOI: 10.1038/s41574-019-0280-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/16/2019] [Indexed: 12/18/2022]
Abstract
The ability of growth hormone (GH) to induce adipose tissue lipolysis has been known for over five decades; however, the molecular mechanisms that mediate this effect and the ability of GH to inhibit insulin-stimulated glucose uptake have scarcely been documented. In this same time frame, our understanding of adipose tissue has evolved to reveal a complex structure with distinct types of adipocyte, depot-specific differences, a biologically significant extracellular matrix and important endocrine properties mediated by adipokines. All these aforementioned features, in turn, can influence lipolysis. In this Review, we provide a historical and current overview of the lipolytic effect of GH in humans, mice and cultured cells. More globally, we explain lipolysis in terms of GH-induced intracellular signalling and its effect on obesity, insulin resistance and lipotoxicity. In this regard, findings that define molecular mechanisms by which GH induces lipolysis are described. Finally, data are presented for the differential effect of GH on specific adipose tissue depots and on distinct classes of metabolically active adipocytes. Together, these cellular, animal and human studies reveal novel cellular phenotypes and molecular pathways regulating the metabolic effects of GH on adipose tissue.
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Affiliation(s)
- John J Kopchick
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA.
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA.
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA.
| | - Darlene E Berryman
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA
| | - Vishwajeet Puri
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA
| | - Kevin Y Lee
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA
| | - Jens O L Jorgensen
- Department of Endocrinology and Diabetes, Aarhus University Hospital, Aarhus, Denmark
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7
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Hansson B, Morén B, Fryklund C, Vliex L, Wasserstrom S, Albinsson S, Berger K, Stenkula KG. Adipose cell size changes are associated with a drastic actin remodeling. Sci Rep 2019; 9:12941. [PMID: 31506540 PMCID: PMC6736966 DOI: 10.1038/s41598-019-49418-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 08/23/2019] [Indexed: 12/21/2022] Open
Abstract
Adipose tissue plays a major role in regulating whole-body insulin sensitivity and energy metabolism. To accommodate surplus energy, the tissue rapidly expands by increasing adipose cell size (hypertrophy) and cell number (hyperplasia). Previous studies have shown that enlarged, hypertrophic adipocytes are less responsive to insulin, and that adipocyte size could serve as a predictor for the development of type 2 diabetes. In the present study, we demonstrate that changes in adipocyte size correlate with a drastic remodeling of the actin cytoskeleton. Expansion of primary adipocytes following 2 weeks of high-fat diet (HFD)-feeding in C57BL6/J mice was associated with a drastic increase in filamentous (F)-actin as assessed by fluorescence microscopy, increased Rho-kinase activity, and changed expression of actin-regulating proteins, favoring actin polymerization. At the same time, increased cell size was associated with impaired insulin response, while the interaction between the cytoskeletal scaffolding protein IQGAP1 and insulin receptor substrate (IRS)-1 remained intact. Reversed feeding from HFD to chow restored cell size, insulin response, expression of actin-regulatory proteins and decreased the amount of F-actin filaments. Together, we report a drastic cytoskeletal remodeling during adipocyte expansion, a process which could contribute to deteriorating adipocyte function.
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Affiliation(s)
- Björn Hansson
- Lund University, Department of Experimental Medical Science, Lund, Sweden
| | - Björn Morén
- Lund University, Department of Experimental Medical Science, Lund, Sweden
| | - Claes Fryklund
- Lund University, Department of Experimental Medical Science, Lund, Sweden
| | - Lars Vliex
- Lund University, Department of Experimental Medical Science, Lund, Sweden.,Maastricht University, Faculty of Health, Medicine and Life Sciences, Maastricht, The Netherlands
| | | | | | - Karin Berger
- Lund University, Department of Experimental Medical Science, Lund, Sweden
| | - Karin G Stenkula
- Lund University, Department of Experimental Medical Science, Lund, Sweden.
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8
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Robinson KN, Rowitz B, Oliphant UJ, Donovan SM, Teran-Garcia M. Larger omental adipocytes correlate with greater Fetuin-A reduction following sleeve gastrectomy. BMC OBESITY 2019; 6:15. [PMID: 31080625 PMCID: PMC6501315 DOI: 10.1186/s40608-019-0238-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 03/12/2019] [Indexed: 01/06/2023]
Abstract
Background Shortly after bariatric surgery, insulin sensitivity improves and circulating Fetuin-A (FetA) declines. Elevated FetA may decrease insulin sensitivity by inhibiting insulin receptor autophosphorylation. FetA also mediates inflammation through toll-like receptor 4 and influences monocyte migration and macrophage polarization in the adipocyte. The role of dietary changes on FetA is unclear. It is also unknown whether changes in FetA are associated with adipocyte size, an indicator of insulin sensitivity. Methods Sleeve gastrectomy patients (n = 39) were evaluated prior to the preoperative diet, on the day of surgery (DOS) and six-weeks postoperatively. At each visit, diet records, anthropometrics and fasting blood were collected. Adipocyte diameter was measured in omental adipose collected during surgery. Results Although significant weight loss did not occur during the preoperative diet, HOMA-IR improved (p < 0.0001) and FetA decreased by 12% (p = 0.01). Six-weeks postoperatively, patients lost 9% of body weight (p = 0.02) and FetA decreased an additional 26% (p < 0.0001). HOMA-IR was unchanged during this time. Omental adipocyte size on DOS was not associated with preoperative changes in dietary intake, body composition or HOMA-IR. However, adipocyte size was strongly associated with both pre- (r = 0.41, p = 0.03) and postoperative (r = − 0.44, p = 0.02) change in FetA. Conclusion FetA began to decrease during the preoperative diet. Greater FetA reduction during this time was associated with smaller adipocytes on DOS. Therefore, immediate, post-bariatric improvements in glucose homeostasis may be partly explained by dietary changes. The preoperative diet protocol significantly reduced insulin resistance, a modifiable risk factor for other non-bariatric procedures. Therefore, this dietary protocol may also be used preoperatively for procedures beyond bariatric surgery.
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Affiliation(s)
- Katie N Robinson
- 1Department of Internal Medicine, University of Iowa, Iowa City, IA USA
| | - Blair Rowitz
- 2Carle Illinois College of Medicine, Urbana, IL USA.,3Department of Surgery, Carle Foundation Hospital, Urbana, IL USA.,4Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Uretz J Oliphant
- 2Carle Illinois College of Medicine, Urbana, IL USA.,3Department of Surgery, Carle Foundation Hospital, Urbana, IL USA
| | - Sharon M Donovan
- 4Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL USA.,5Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Margarita Teran-Garcia
- 2Carle Illinois College of Medicine, Urbana, IL USA.,4Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL USA.,6Department of Human Development and Family Studies, University of Illinois at Urbana-Champaign, Urbana, IL USA
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9
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Luong Q, Huang J, Lee KY. Deciphering White Adipose Tissue Heterogeneity. BIOLOGY 2019; 8:biology8020023. [PMID: 30978929 PMCID: PMC6628053 DOI: 10.3390/biology8020023] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 01/09/2023]
Abstract
Adipose tissue not only stores energy, but also controls metabolism through secretion of hormones, cytokines, proteins, and microRNAs that affect the function of cells and tissues throughout the body. Adipose tissue is organized into discrete depots throughout the body, and these depots are differentially associated with insulin resistance and increased risk of metabolic disease. In addition to energy-dissipating brown and beige adipocytes, recent lineage tracing studies have demonstrated that individual adipose depots are composed of white adipocytes that are derived from distinct precursor populations, giving rise to distinct subpopulations of energy-storing white adipocytes. In this review, we discuss this developmental and functional heterogeneity of white adipocytes both between and within adipose depots. In particular, we will highlight findings from our recent manuscript in which we find and characterize three major subtypes of white adipocytes. We will discuss these data relating to the differences between subcutaneous and visceral white adipose tissue and in relationship to previous work deciphering adipocyte heterogeneity within adipose tissue depots. Finally, we will discuss the possible implications of adipocyte heterogeneity may have for the understanding of lipodystrophies.
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Affiliation(s)
- Quyen Luong
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA.
- The Diabetes Institute, Ohio University, Athens, OH 45701, USA.
| | - Jun Huang
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA.
- The Diabetes Institute, Ohio University, Athens, OH 45701, USA.
| | - Kevin Y Lee
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA.
- The Diabetes Institute, Ohio University, Athens, OH 45701, USA.
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10
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McLaughlin T, Abbasi F, Lamendola C, Yee G, Carter S, Cushman SW. Dietary weight loss in insulin-resistant non-obese humans: Metabolic benefits and relationship to adipose cell size. Nutr Metab Cardiovasc Dis 2019; 29:62-68. [PMID: 30497926 PMCID: PMC6410738 DOI: 10.1016/j.numecd.2018.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 09/27/2018] [Accepted: 09/28/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND AIMS Overweight and obesity increase risk for diabetes and cardiovascular disease, largely through development of insulin resistance. Benefits of dietary weight loss are documented for obese individuals with insulin resistance. Similar benefits have not been shown in overweight individuals. We sought to quantify whether dietary weight loss improves metabolic risk profile in overweight insulin-resistant individuals, and evaluated potential mediators between weight loss and metabolic response. METHODS AND RESULTS Healthy volunteers with BMI 25-29.9 kg/m2 underwent detailed metabolic phenotyping including insulin-mediated-glucose disposal, fasting/daylong glucose, insulin, triglycerides, FFA, and cholesterol. Subcutaneous fat biopsies were performed for measurement of adipose cell size. After 14 weeks of hypocaloric diet and 2 weeks of weight maintenance, cardiometabolic measures and biopsies were repeated. Changes in weight, % body fat, waist circumference, adipose cell size and FFA were evaluated as predictors of change in insulin resistance. Weight loss (4.3 kg) yielded significant improvements in insulin resistance and all cardiovascular risk markers except glucose, HDL-C, and LDL-C. Improvement in insulin sensitivity was greater among those with <2 vs >2 cardiovascular risk factors at baseline. Decrease in adipose cell size and waist circumference, but not weight or body fat, independently predicted improvement in insulin resistance. CONCLUSIONS Weight loss yields metabolic health benefits in insulin-resistant overweight adults, even in the absence of classic cardiovascular risk factors. Weight loss-related improvement in insulin sensitivity may be mediated through changes in adipose cell size and/or central distribution of body fat. The insulin-resistant subgroup of overweight individuals should be identified and targeted for dietary weight loss. CLINICAL TRIALS IDENTIFIER NCT00186459.
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Affiliation(s)
- T McLaughlin
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305, USA.
| | - F Abbasi
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - C Lamendola
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - G Yee
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - S Carter
- Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - S W Cushman
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
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11
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Lee KY, Luong Q, Sharma R, Dreyfuss JM, Ussar S, Kahn CR. Developmental and functional heterogeneity of white adipocytes within a single fat depot. EMBO J 2018; 38:embj.201899291. [PMID: 30530479 DOI: 10.15252/embj.201899291] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 10/30/2018] [Accepted: 11/05/2018] [Indexed: 02/06/2023] Open
Abstract
Recent studies suggest that, even within a single adipose depot, there may be distinct subpopulations of adipocytes. To investigate this cellular heterogeneity, we have developed multiple conditionally immortalized clonal preadipocyte lines from white adipose tissue of mice. Analysis of these clones reveals at least three white adipocyte subpopulations. These subpopulations have differences in metabolism and differentially respond to inflammatory cytokines, insulin, and growth hormones. These also have distinct gene expression profiles and can be tracked by differential expression of three marker genes: Wilms' tumor 1, transgelin, and myxovirus 1. Lineage tracing analysis with dual-fluorescent reporter mice indicates that these adipocyte subpopulations have differences in gene expression and metabolism that mirror those observed in the clonal cell lines. Furthermore, preadipocytes and adipocytes from these subpopulations differ in their abundance in different fat depots. Thus, white adipose tissue, even in a single depot, is comprised of distinct subpopulations of white adipocytes with different physiological phenotypes. These differences in adipocyte composition may contribute to the differences in metabolic behavior and physiology of different fat depots.
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Affiliation(s)
- Kevin Y Lee
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA .,Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA.,The Diabetes Institute, Ohio University, Athens, OH, USA
| | - Quyen Luong
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA.,The Diabetes Institute, Ohio University, Athens, OH, USA
| | - Rita Sharma
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA.,The Diabetes Institute, Ohio University, Athens, OH, USA
| | - Jonathan M Dreyfuss
- Bioinformatics Core, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA.,Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Siegfried Ussar
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA.,RG Adipocytes & Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Center Munich, Neuherberg, Germany.,German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - C Ronald Kahn
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
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12
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Adipose tissue dysfunction is associated with low levels of the novel Palmitic Acid Hydroxystearic Acids. Sci Rep 2018; 8:15757. [PMID: 30361530 PMCID: PMC6202399 DOI: 10.1038/s41598-018-34113-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/09/2018] [Indexed: 12/18/2022] Open
Abstract
Adipose tissue dysfunction is considered an important contributor to systemic insulin resistance and Type 2 diabetes (T2D). Recently, a novel family of endogenous lipids, palmitic acid hydroxy stearic acids (PAHSAs), was discovered. These have anti-diabetic and anti-inflammatory effects in mice and are reduced in serum and adipose tissue of insulin resistant humans. In the present study, we investigate if adipose tissue dysfunction is associated with reduced PAHSA levels in human subjects and if PAHSAs influence adipocyte differentiation. Our results show that low expression of adipocyte GLUT4 and adipocyte hypertrophy, markers of adipose tissue dysfunction, are associated with reduced expression of key enzymes for de novo lipogenesis and adipose tissue levels of PAHSAs in human subjects. We also show that GLUT4 is not only a marker of adipose tissue dysfunction, but may be causally related to the observed impairments. PAHSAs may also act locally in the adipose tissue to improve adipogenesis through a mechanism bypassing direct activation of peroxisome proliferator-activated receptor (PPARγ). The discovery of PAHSAs and our current results provide novel insights into positive effects of lipid species in adipose tissue and mechanisms by which dysfunctional adipose tissue is associated with insulin resistance and risk of developing T2D.
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13
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Hansson B, Wasserstrom S, Morén B, Periwal V, Vikman P, Cushman SW, Göransson O, Storm P, Stenkula KG. Intact glucose uptake despite deteriorating signaling in adipocytes with high-fat feeding. J Mol Endocrinol 2018; 60:199-211. [PMID: 29339400 PMCID: PMC7459392 DOI: 10.1530/jme-17-0195] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 01/16/2018] [Indexed: 12/27/2022]
Abstract
To capture immediate cellular changes during diet-induced expansion of adipocyte cell volume and number, we characterized mature adipocytes during a short-term high-fat diet (HFD) intervention. Male C57BL6/J mice were fed chow diet, and then switched to HFD for 2, 4, 6 or 14 days. Systemic glucose clearance was assessed by glucose tolerance test. Adipose tissue was dissected for RNA-seq and cell size distribution analysis using coulter counting. Insulin response in isolated adipocytes was monitored by glucose uptake assay and Western blotting, and confocal microscopy was used to assess autophagic activity. Switching to HFD was accompanied by an immediate adipocyte size expansion and onset of systemic insulin resistance already after two days, followed by recruitment of new adipocytes. Despite an initially increased non-stimulated and preserved insulin-stimulated glucose uptake, we observed a decreased phosphorylation of insulin receptor substrate-1 (IRS-1) and protein kinase B (PKB). After 14 days of HFD, both the insulin-stimulated phosphorylation of Akt substrate of 160 kDa (AS160) and glucose uptake was blunted. RNA-seq analysis of adipose tissue revealed transient changes in gene expression at day four, including highly significant upregulation of Trp53inp, previously demonstrated to be involved in autophagy. We confirmed increased autophagy, measured as an increased density of LC3-positive puncta and decreased p62 expression after 14 days of HFD. In conclusion, HFD rapidly induced systemic insulin resistance, whereas insulin-stimulated glucose uptake remained intact throughout 6 days of HFD feeding. We also identified autophagy as an early cellular process that potentially influences adipocyte function upon switching to HFD.
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Affiliation(s)
- Björn Hansson
- Department of Experimental Medical ScienceLund University, Lund, Sweden
| | | | - Björn Morén
- Department of Experimental Medical ScienceLund University, Lund, Sweden
| | - Vipul Periwal
- National Institute of Diabetes and Digestive and Kidney DiseasesNational Institutes of Health, Bethesda, Maryland, USA
| | - Petter Vikman
- Department of Clinical SciencesLund University, Malmö, Sweden
| | - Samuel W Cushman
- National Institute of Diabetes and Digestive and Kidney DiseasesNational Institutes of Health, Bethesda, Maryland, USA
| | - Olga Göransson
- Department of Experimental Medical ScienceLund University, Lund, Sweden
| | - Petter Storm
- Department of Clinical SciencesLund University, Malmö, Sweden
| | - Karin G Stenkula
- Department of Experimental Medical ScienceLund University, Lund, Sweden
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14
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Liotti A, Cabaro S, Cimmino I, Ricci S, Procaccini C, Paciello O, Raciti GA, Spinelli R, Iossa S, Matarese G, Miele C, Formisano P, Beguinot F, Oriente F. Prep1 deficiency improves metabolic response in white adipose tissue. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:515-525. [PMID: 29474930 DOI: 10.1016/j.bbalip.2018.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 02/09/2018] [Accepted: 02/17/2018] [Indexed: 12/13/2022]
Abstract
Prep1 is a gene encoding for a homeodomain transcription factor which induces hepatic and muscular insulin resistance. In this study, we show that Prep1 hypomorphic heterozygous (Prep1i/+) mice, expressing low levels of protein, featured a 23% and a 25% reduction of total body lipid content and epididymal fat, respectively. The percentage of the small adipocytes (25-75 μm) was 30% higher in Prep1i/+ animals than in the WT, with a reciprocal difference in the large adipose cells (100-150 and >150 μm). Insulin-stimulated insulin receptor tyrosine and Akt serine phosphorylation markedly increased in Prep1i/+ mice, paralleled by 3-fold higher glucose uptake and a significant increase of proadipogenic genes such as C/EBPα, GLUT4, and FABP4. Moreover, T cells infiltration and TNF-α, IFNγ and leptin expression were reduced in adipose tissue from Prep1i/+ mice, while adiponectin levels were 2-fold higher. Furthermore, Prep1i/+ mature adipocytes released lower amounts of pro-inflammatory cytokines and higher amount of adiponectin compared to WT cells. Incubation of murine liver cell line (NMuLi) with conditioned media (CM) from mature adipocytes of Prep1i/+ mice improved glucose metabolism, while those from WT mice had no effect. Consistent with these data, Prep1 overexpression in 3T3-L1 adipocytes impaired adipogenesis and insulin signaling, and increased proinflammatory cytokine secretion. All these findings suggest that Prep1 silencing reduces inflammatory response and increases insulin sensitivity in adipose tissue. In addition, CM from mature adipocytes of Prep1i/+ mice improve metabolism in hepatic cells.
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Affiliation(s)
- Antonietta Liotti
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Serena Cabaro
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Ilaria Cimmino
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Serena Ricci
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Claudio Procaccini
- Laboratory of Immunology, National Council of Research (CNR), Naples, Italy
| | - Orlando Paciello
- Department of Veterinary Medicine and Animal Production, Federico II University of Naples, Naples, Italy
| | - Gregory A Raciti
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Rosa Spinelli
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Susanna Iossa
- Department of Biology, Federico II University of Naples, Naples, Italy
| | - Giuseppe Matarese
- Laboratory of Immunology, National Council of Research (CNR), Naples, Italy
| | - Claudia Miele
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Pietro Formisano
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Francesco Beguinot
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy
| | - Francesco Oriente
- Department of Translational Medicine, Federico II University of Naples and URT "Genomic of Diabetes" of Institute of Experimental Endocrinology and Oncology, National Council of Research (CNR), Naples, Italy.
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15
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Lee KY, Sharma R, Gase G, Ussar S, Li Y, Welch L, Berryman DE, Kispert A, Bluher M, Kahn CR. Tbx15 Defines a Glycolytic Subpopulation and White Adipocyte Heterogeneity. Diabetes 2017; 66:2822-2829. [PMID: 28847884 PMCID: PMC5652605 DOI: 10.2337/db17-0218] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 08/20/2017] [Indexed: 01/11/2023]
Abstract
Tbx15 is a member of the T-box gene family of mesodermal developmental genes. We have recently shown that Tbx15 plays a critical role in the formation and metabolic programming of glycolytic myofibers in skeletal muscle. Tbx15 is also differentially expressed among white adipose tissue (WAT) in different body depots. In the current study, using three independent methods, we show that even within a single WAT depot, high Tbx15 expression is restricted to a subset of preadipocytes and mature white adipocytes. Gene expression and metabolic profiling demonstrate that the Tbx15Hi preadipocyte and adipocyte subpopulations of cells are highly glycolytic, whereas Tbx15Low preadipocytes and adipocytes in the same depot are more oxidative and less glycolytic. Likewise, in humans, expression of TBX15 in subcutaneous and visceral WAT is positively correlated with markers of glycolytic metabolism and inversely correlated with obesity. Furthermore, overexpression of Tbx15 is sufficient to reduce oxidative and increase glycolytic metabolism in cultured adipocytes. Thus, Tbx15 differentially regulates oxidative and glycolytic metabolism within subpopulations of white adipocytes and preadipocytes. This leads to a functional heterogeneity of cellular metabolism within WAT that has potential impact in the understanding of human metabolic diseases.
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Affiliation(s)
- Kevin Y Lee
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH
- The Diabetes Institute, Ohio University, Athens, OH
| | - Rita Sharma
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH
- The Diabetes Institute, Ohio University, Athens, OH
| | - Grant Gase
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH
- The Diabetes Institute, Ohio University, Athens, OH
| | - Siegfried Ussar
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA
- JRG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Yichao Li
- Russ College of Engineering and Technology, Ohio University, Athens, OH
| | - Lonnie Welch
- Russ College of Engineering and Technology, Ohio University, Athens, OH
| | - Darlene E Berryman
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH
- The Diabetes Institute, Ohio University, Athens, OH
| | - Andreas Kispert
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Matthias Bluher
- Department of Molecular Endocrinology, University of Leipzig, Leipzig, Germany
| | - C Ronald Kahn
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA
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16
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Kim SP, Frey JL, Li Z, Goh BC, Riddle RC. Lack of Lrp5 Signaling in Osteoblasts Sensitizes Male Mice to Diet-Induced Disturbances in Glucose Metabolism. Endocrinology 2017; 158:3805-3816. [PMID: 28938444 PMCID: PMC5695825 DOI: 10.1210/en.2017-00657] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/06/2017] [Indexed: 01/16/2023]
Abstract
Wnt signaling through the low-density lipoprotein-related receptor 5 (Lrp5) coreceptor regulates osteoblast maturation, matrix mineralization, and intermediary metabolism. In the mature osteoblast, signals downstream of Lrp5 are required for normal long-chain fatty acid β-oxidation. Mice rendered deficient for this coreceptor in osteoblasts and osteocytes accumulate body fat with elevated serum lipid levels but retain normal insulin sensitivity. In the present study, we challenged Lrp5-mutant mice with a high-fat diet (HFD) to determine whether they were more susceptible to diet-induced disturbances in glucose homeostasis. The HFD-fed Lrp5 mutant mice maintained a low bone mass phenotype with an increase in adipose tissue mass and hypertriglyceridemia and hypercholesterolemia. Examination of glucose metabolism revealed that Lrp5 deficiency in the osteoblast also resulted in hyperglycemia and hyperinsulinemia, with reductions in glucose tolerance, insulin sensitivity, and serum undercarboxylated osteocalcin. The results from in vivo genetic epistasis and in vitro studies suggest that this phenotype proceeds via the accumulation of diacylglycerol species and impaired insulin signaling in Lrp5-deficient osteoblasts. In turn, glucose uptake and osteocalcin production are diminished in mutant osteoblasts. Taken together, these data identify a link between Wnt-Lrp5 signaling and insulin signaling in the osteoblast that has the potential to influence energy balance and compound the detrimental effects of a HFD on whole-body metabolism.
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Affiliation(s)
- Soohyun P. Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Julie L. Frey
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Zhu Li
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Brian C. Goh
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201
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17
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He JH, Yan M, Zuo H, Niu S, Yuan J, Weng SP, He J, Xu X. High reduced/oxidized glutathione ratio in infectious spleen and kidney necrosis virus-infected cells contributes to degradation of VP08R multimers. Vet Microbiol 2017; 207:19-24. [PMID: 28757023 DOI: 10.1016/j.vetmic.2017.05.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/22/2017] [Accepted: 05/29/2017] [Indexed: 12/29/2022]
Abstract
Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the genus Megalocytivirus, family Iridoviridae. The ISKNV-infected cells in fish tissues are attached by lymphatic endothelial cells (LECs), which is a unique pathological phenomenon of ISKNV infection. The viral proteins VP23R and VP08R and the host protein nidogen-1 constitute the virus-mock basement membrane (VMBM) on the membrane of infected cells to provide attaching sites for LECs. VP08R can form cross-linked multimers via intermolecular disulfide bonds to make VMBM a compact and strong structure. A question is that when the virions mature, how do they penetrate VMBMs to be released from the cells? In this study, the redox state in ISKNV-infected cells was investigated. We demonstrated that the ratio of reduced/oxidized glutathione (GSH/GSSG) was significantly elevated in ISKNV-infected cells, suggesting the increasing of reducing power. Remarkable changes were also observed in activities of many GSH metabolic enzymes and in the ratio of NADPH/NADP. We further exhibited that the high ratio of GSH/GSSG could lead to degradation of the VP08R multimer in vitro. These may suggest that the high GSH/GSSG ratio in infected cells could act on the VP08R multimer to facilitate the disassembly of VMBMs after virus maturation.
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Affiliation(s)
- Jian-Hui He
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China
| | - Muting Yan
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China
| | - Hongliang Zuo
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China; School of Marine Sciences, Sun Yat-sen University, Guangzhou, PR China; South China Sea Resource Exploitation and Protection Collaborative Innovation Center (SCS-REPIC), Guangzhou, PR China
| | - Shengwen Niu
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China
| | - Jia Yuan
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China
| | - Shao-Ping Weng
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China; South China Sea Resource Exploitation and Protection Collaborative Innovation Center (SCS-REPIC), Guangzhou, PR China
| | - Jianguo He
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China; School of Marine Sciences, Sun Yat-sen University, Guangzhou, PR China; South China Sea Resource Exploitation and Protection Collaborative Innovation Center (SCS-REPIC), Guangzhou, PR China.
| | - Xiaopeng Xu
- MOE Key Laboratory of Aquatic Product Safety / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China; Institute of Aquatic Economic Animals and Guangdong Provice Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, PR China; South China Sea Resource Exploitation and Protection Collaborative Innovation Center (SCS-REPIC), Guangzhou, PR China.
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18
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Ma X, Fang W, Jiang Z, Wang L, Yang X, Gao K. Dibutyryl-cAMP affecting fat deposition of finishing pigs by decreasing the inflammatory system related to insulin sensitive or lipolysis. GENES AND NUTRITION 2016; 11:17. [PMID: 27551318 PMCID: PMC4968439 DOI: 10.1186/s12263-016-0531-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 05/09/2016] [Indexed: 12/02/2022]
Abstract
Background The mechanism of db-cAMP regulating fat deposition and improving lean percentage is unclear and needs to be further studied. Methods Eighteen 100-day-old Duroc × Landrance × Large White barrows (49.75 ± 0.75 kg) were used for experiment 1, and 15 eighteen 135-day-old barrows (78.34 ± 1.22 kg) were used for experiment 2 to investigate the effects of dietary dibutyryl-cAMP (db-cAMP) on fat deposition in finishing pigs. Pigs were fed with a corn-soybean meal-based diet supplemented with 0 or 15 mg/kg db-cAMP, and both experiments lasted 35 days, respectively. Results The results showed that db-cAMP decreased the backfat thickness, backfat percentage, and diameter of backfat cells without changing the growth performance or carcass characteristics in both experiments, and this effect was more marked in experiment 1 than in experiment 2; db-cAMP enhanced the activity of the growth hormone–insulin-like growth factor-1 (GH-IGF-1) axis and pro-opiomelanocortin (POMC) system in both experiments, which suppressed the accumulation of backfat deposition; microarray analysis showed that db-cAMP suppressed the inflammatory system within the adipose tissue related to insulin sensitivity, which also reduced fat synthesis. Conclusions In summary, the effect of db-cAMP on suppressing fat synthesis and accumulation is better in the earlier phase than in the later phase of finishing pigs, and db-cAMP plays this function by increasing the activity of the GH-IGF-1 axis and POMC system, while decreasing the inflammatory system within the adipose tissue related to insulin sensitive or lipolysis.
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Affiliation(s)
- Xianyong Ma
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, 510640 Guangzhou, China ; The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, 510640 Guangzhou, China ; State Key Laboratory of Livestock and Poultry Breeding, 510640 Guangzhou, China ; Guangdong Public Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China ; Guangdong Key Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China
| | - Wei Fang
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, 510640 Guangzhou, China ; The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, 510640 Guangzhou, China ; State Key Laboratory of Livestock and Poultry Breeding, 510640 Guangzhou, China ; Guangdong Public Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China ; Guangdong Key Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China
| | - Zongyong Jiang
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, 510640 Guangzhou, China ; The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, 510640 Guangzhou, China ; State Key Laboratory of Livestock and Poultry Breeding, 510640 Guangzhou, China ; Guangdong Public Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China ; Guangdong Key Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China
| | - Li Wang
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, 510640 Guangzhou, China ; The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, 510640 Guangzhou, China ; State Key Laboratory of Livestock and Poultry Breeding, 510640 Guangzhou, China ; Guangdong Public Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China ; Guangdong Key Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China
| | - Xuefen Yang
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, 510640 Guangzhou, China ; The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, 510640 Guangzhou, China ; State Key Laboratory of Livestock and Poultry Breeding, 510640 Guangzhou, China ; Guangdong Public Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China ; Guangdong Key Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China
| | - Kaiguo Gao
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, 510640 Guangzhou, China ; The Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, 510640 Guangzhou, China ; State Key Laboratory of Livestock and Poultry Breeding, 510640 Guangzhou, China ; Guangdong Public Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China ; Guangdong Key Laboratory of Animal Breeding and Nutrition, 510640 Guangzhou, China
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19
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Rajan MR, Nyman E, Kjølhede P, Cedersund G, Strålfors P. Systems-wide Experimental and Modeling Analysis of Insulin Signaling through Forkhead Box Protein O1 (FOXO1) in Human Adipocytes, Normally and in Type 2 Diabetes. J Biol Chem 2016; 291:15806-19. [PMID: 27226562 DOI: 10.1074/jbc.m116.715763] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 01/31/2023] Open
Abstract
Insulin resistance is a major aspect of type 2 diabetes (T2D), which results from impaired insulin signaling in target cells. Signaling to regulate forkhead box protein O1 (FOXO1) may be the most important mechanism for insulin to control transcription. Despite this, little is known about how insulin regulates FOXO1 and how FOXO1 may contribute to insulin resistance in adipocytes, which are the most critical cell type in the development of insulin resistance. We report a detailed mechanistic analysis of insulin control of FOXO1 in human adipocytes obtained from non-diabetic subjects and from patients with T2D. We show that FOXO1 is mainly phosphorylated through mTORC2-mediated phosphorylation of protein kinase B at Ser(473) and that this mechanism is unperturbed in T2D. We also demonstrate a cross-talk from the MAPK branch of insulin signaling to stimulate phosphorylation of FOXO1. The cellular abundance and consequently activity of FOXO1 are halved in T2D. Interestingly, inhibition of mTORC1 with rapamycin reduces the abundance of FOXO1 to the levels in T2D. This suggests that the reduction of the concentration of FOXO1 is a consequence of attenuation of mTORC1, which defines much of the diabetic state in human adipocytes. We integrate insulin control of FOXO1 in a network-wide mathematical model of insulin signaling dynamics based on compatible data from human adipocytes. The diabetic state is network-wide explained by attenuation of an mTORC1-to-insulin receptor substrate-1 (IRS1) feedback and reduced abundances of insulin receptor, GLUT4, AS160, ribosomal protein S6, and FOXO1. The model demonstrates that attenuation of the mTORC1-to-IRS1 feedback is a major mechanism of insulin resistance in the diabetic state.
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Affiliation(s)
| | - Elin Nyman
- Biomedical Engineering, Linköping University, SE58185 Linköping, Sweden and Cardiovascular and Metabolic Diseases, Innovative Medicines, and Drug Metabolism and Pharmacokinetics, AstraZeneca Research and Development, 43150 Gothenburg, Sweden
| | - Preben Kjølhede
- From the Departments of Clinical and Experimental Medicine and
| | - Gunnar Cedersund
- From the Departments of Clinical and Experimental Medicine and Biomedical Engineering, Linköping University, SE58185 Linköping, Sweden and
| | - Peter Strålfors
- From the Departments of Clinical and Experimental Medicine and
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20
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Arriarán S, Agnelli S, Remesar X, Fernández-López JA, Alemany M. Effects of sex and site on amino acid metabolism enzyme gene expression and activity in rat white adipose tissue. PeerJ 2015; 3:e1399. [PMID: 26587356 PMCID: PMC4647552 DOI: 10.7717/peerj.1399] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/21/2015] [Indexed: 11/20/2022] Open
Abstract
Background and Objectives. White adipose tissue (WAT) shows marked sex- and diet-dependent differences. However, our metabolic knowledge of WAT, especially on amino acid metabolism, is considerably limited. In the present study, we compared the influence of sex on the amino acid metabolism profile of the four main WAT sites, focused on the paths related to ammonium handling and the urea cycle, as a way to estimate the extent of WAT implication on body amino-nitrogen metabolism. Experimental Design. Adult female and male rats were maintained, undisturbed, under standard conditions for one month. After killing them under isoflurane anesthesia. WAT sites were dissected and weighed. Subcutaneous, perigonadal, retroperitoneal and mesenteric WAT were analyzed for amino acid metabolism gene expression and enzyme activities. Results. There was a considerable stability of the urea cycle activities and expressions, irrespective of sex, and with only limited influence of site. Urea cycle was more resilient to change than other site-specialized metabolic pathways. The control of WAT urea cycle was probably related to the provision of arginine/citrulline, as deduced from the enzyme activity profiles. These data support a generalized role of WAT in overall amino-N handling. In contrast, sex markedly affected WAT ammonium-centered amino acid metabolism in a site-related way, with relatively higher emphasis in males' subcutaneous WAT. Conclusions. We found that WAT has an active amino acid metabolism. Its gene expressions were lower than those of glucose-lipid interactions, but the differences were quantitatively less important than usually reported. The effects of sex on urea cycle enzymes expression and activity were limited, in contrast with the wider variations observed in other metabolic pathways. The results agree with a centralized control of urea cycle operation affecting the adipose organ as a whole.
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Affiliation(s)
- Sofía Arriarán
- Department of Nutrition & Food Science, University of Barcelona, Faculty of Biology , Barcelona , Spain
| | - Silvia Agnelli
- Department of Nutrition & Food Science, University of Barcelona, Faculty of Biology , Barcelona , Spain
| | - Xavier Remesar
- Department of Nutrition & Food Science, University of Barcelona, Faculty of Biology , Barcelona , Spain ; Institute of Biomedicine, University of Barcelona , Barcelona , Spain ; CIBER OBN , Barcelona , Spain
| | - José Antonio Fernández-López
- Department of Nutrition & Food Science, University of Barcelona, Faculty of Biology , Barcelona , Spain ; Institute of Biomedicine, University of Barcelona , Barcelona , Spain ; CIBER OBN , Barcelona , Spain
| | - Marià Alemany
- Department of Nutrition & Food Science, University of Barcelona, Faculty of Biology , Barcelona , Spain ; Institute of Biomedicine, University of Barcelona , Barcelona , Spain ; CIBER OBN , Barcelona , Spain
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21
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Fang L, Guo F, Zhou L, Stahl R, Grams J. The cell size and distribution of adipocytes from subcutaneous and visceral fat is associated with type 2 diabetes mellitus in humans. Adipocyte 2015; 4:273-9. [PMID: 26451283 DOI: 10.1080/21623945.2015.1034920] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/13/2015] [Accepted: 03/23/2015] [Indexed: 01/11/2023] Open
Abstract
AIMS/HYPOTHESIS Regional deposition of adipose tissue and adipocyte morphology may contribute to increased risk for insulin resistance. The aim of this study was to compare adipocyte cell size and size distribution from multiple fat depots and to determine the association with type 2 diabetes mellitus, anthropomorphic data, and subjects' metabolic profile. METHODS Clinical data and adipose tissue from subcutaneous fat, omentum, and mesentery were collected from 30 subjects with morbid obesity. Adipocytes were isolated by collagenase digestion and sized by microscopic measurement of cell diameter. RESULTS Overall, adipocytes from subcutaneous fat were larger than those from omentum or mesentery. For the subcutaneous and omental fat depots, there was a significant increase in % small cells (14.9% vs 31.4%, p = 0 .006 and 14.0% vs 30.5%, p = 0 .015, respectively) and corresponding decrease in % large cells for nondiabetic vs diabetic patients. There was a similar trend for mesentery but it did not reach statistical significance (p = 0 .090). For omentum and mesentery, there was also a significant decrease in the diameter of the small cells. Fasting glucose was positively correlated with fraction of small cells in omentum and mesentery, and HbA1C was positively correlated with fraction of small cells in the omental fat depot. There was no correlation between large cell diameter with clinical parameters in any of the fat depots. CONCLUSIONS/INTERPRETATION These results indicate size distribution of adipocytes, specifically an increase in the fraction of small cells, is associated with the presence of type 2 diabetes mellitus.
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Varlamov O, Chu M, Cornea A, Sampath H, Roberts CT. Cell-autonomous heterogeneity of nutrient uptake in white adipose tissue of rhesus macaques. Endocrinology 2015; 156:80-9. [PMID: 25356825 PMCID: PMC4272393 DOI: 10.1210/en.2014-1699] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phenotypic diversity may play an adaptive role by providing graded biological responses to fluctuations in environmental stimuli. We used single-cell imaging of the metabolizable fluorescent fatty acid analog 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-C12 and fluorescent 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG) to explore cellular heterogeneity in nutrient uptake in white adipose tissue (WAT) explants of rhesus macaques. Surprisingly, WAT displayed a striking cell size-independent mosaic pattern, in that adjacent adipocytes varied with respect to insulin-stimulated BODIPY-C12 and 2-NBDG uptake. Relative free fatty acid (FFA) transport activity correlated with the cellular levels of FFA transporter protein-1 and the scavenger receptor CD36 in individual adipocytes. In vitro incubation of WAT explants for 24 hours caused partial desynchronization of cellular responses, suggesting that adipocytes may slowly alter their differential nutrient uptake activity. In vitro-differentiated human adipocytes also exhibited a mosaic pattern of BODIPY-C12 uptake. WAT from animals containing a homogeneous population of large adipocytes was nonmosaic, in that every adipocyte exhibited a similar level of BODIPY-C12 fluorescence, suggesting that the development of obesity is associated with the loss of heterogeneity in WAT. Hence, for the first time, we demonstrate an intrinsic heterogeneity in FFA and glucose transport activity in WAT.
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Affiliation(s)
- Oleg Varlamov
- Divisions of Diabetes, Obesity, and Metabolism and Developmental and Reproductive Science (O.V., C.T.R.), and Division of Neuroscience (A.C.), Oregon National Primate Research Center, Beaverton, Oregon 97006; and Division of Endocrinology, Diabetes, and Clinical Nutrition, Department of Medicine (M.C., C.T.R.) and Center for Research Occupational and Environmental Toxicology (H.S.), Oregon Health and Science University, Portland, Oregon 97239
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GLUT4 defects in adipose tissue are early signs of metabolic alterations in Alms1GT/GT, a mouse model for obesity and insulin resistance. PLoS One 2014; 9:e109540. [PMID: 25299671 PMCID: PMC4192353 DOI: 10.1371/journal.pone.0109540] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 09/10/2014] [Indexed: 01/26/2023] Open
Abstract
Dysregulation of signaling pathways in adipose tissue leading to insulin resistance can contribute to the development of obesity-related metabolic disorders. Alström Syndrome, a recessive ciliopathy, caused by mutations in ALMS1, is characterized by progressive metabolic alterations such as childhood obesity, hyperinsulinemia, and type 2 diabetes. Here we investigated the role of Alms1 disruption in AT expansion and insulin responsiveness in a murine model for Alström Syndrome. A gene trap insertion in Alms1 on the insulin sensitive C57BL6/Ei genetic background leads to early hyperinsulinemia and a progressive increase in body weight. At 6 weeks of age, before the onset of the metabolic disease, the mutant mice had enlarged fat depots with hypertrophic adipocytes, but without signs of inflammation. Expression of lipogenic enzymes was increased. Pre-adipocytes isolated from mutant animals demonstrated normal adipogenic differentiation but gave rise to mature adipocytes with reduced insulin-stimulated glucose uptake. Assessment of whole body glucose homeostasis revealed glucose intolerance. Insulin stimulation resulted in proper AKT phosphorylation in adipose tissue. However, the total amount of glucose transporter 4 (SLC4A2) and its translocation to the plasma membrane were reduced in mutant adipose depots compared to wildtype littermates. Alterations in insulin stimulated trafficking of glucose transporter 4 are an early sign of metabolic dysfunction in Alström mutant mice, providing a possible explanation for the reduced glucose uptake and the compensatory hyperinsulinemia. The metabolic signaling deficits either reside downstream or are independent of AKT activation and suggest a role for ALMS1 in GLUT4 trafficking. Alström mutant mice represent an interesting model for the development of metabolic disease in which adipose tissue with a reduced glucose uptake can expand by de novo lipogenesis to an obese state.
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Ochner CN, Barrios DM, Lee CD, Pi-Sunyer FX. Biological mechanisms that promote weight regain following weight loss in obese humans. Physiol Behav 2013; 120:106-13. [PMID: 23911805 DOI: 10.1016/j.physbeh.2013.07.009] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 04/05/2013] [Accepted: 07/23/2013] [Indexed: 01/25/2023]
Abstract
Weight loss dieting remains the treatment of choice for the vast majority of obese individuals, despite the limited long-term success of behavioral weight loss interventions. The reasons for the near universal unsustainability of behavioral weight loss in [formerly] obese individuals have not been fully elucidated, relegating researchers to making educated guesses about how to improve obesity treatment, as opposed to developing interventions targeting the causes of weight regain. This article discusses research on several factors that may contribute to weight regain following weight loss achieved through behavioral interventions, including adipose cellularity, endocrine function, energy metabolism, neural responsivity, and addiction-like neural mechanisms. All of these mechanisms are engaged prior to weight loss, suggesting that these so called "anti-starvation" mechanisms are activated via reductions in energy intake, rather than depletion of energy stores. Evidence suggests that these mechanisms are not necessarily part of a homeostatic feedback system designed to regulate body weight, or even anti-starvation mechanisms per se. Although they may have evolved to prevent starvation, they appear to be more accurately described as anti-weight loss mechanisms, engaged with caloric restriction irrespective of the adequacy of energy stores. It is hypothesized that these factors may combine to create a biological disposition that fosters the maintenance of an elevated body weight and works to restore the highest sustained body weight, thus precluding the long-term success of behavioral weight loss. It may be necessary to develop interventions that attenuate these biological mechanisms in order to achieve long-term weight reduction in obese individuals.
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Affiliation(s)
- Christopher N Ochner
- New York Obesity Nutrition Research Center, St. Luke's Roosevelt Hospital, Columbia University College of Physicians and Surgeons, New York, NY, USA; Mount Sinai Adolescent Health Center, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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Hulstrøm V, Prats C, Vinten J. Adipocyte size and cellular expression of caveolar proteins analyzed by confocal microscopy. Am J Physiol Cell Physiol 2013; 304:C1168-75. [DOI: 10.1152/ajpcell.00273.2012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Caveolae are abundant in adipocytes and are involved in the regulation of lipid accumulation, which is the main volume determinant of these cells. We have developed and applied a confocal microscopic technique for measuring individual cellular expression of the caveolar proteins cavin-1 and caveolin-1 along with the size of individual adipocytes. The technique was applied on collagenase isolated adipocytes from ad libitum fed Sprague-Dawley rats of different age (4–26 wk) and weight (103–629 g). We found that cellular expression of caveolar proteins was variable (SD of log expression in the range from 0.25 to 0.65). Regression analysis of protein expression on adipocyte size revealed that the expression of the caveolar proteins cavin-1 and caveolin-1 on adipocytes from individual rats was tightly related to adipocyte cell surface area (mean coefficient of regression was 0.83 for cavin and 0.77 for caveolin), indicating that caveolar density was the same in membranes from all cells within a biopsy. This intrinsic relation remained unchanged with animal age, but adipocytes from animals with increasing age showed a decrease in mean expression of caveolar proteins per unit cell surface. The different relation between adipocyte size and cellular expression levels of caveolar proteins within and between individuals of different age shows that caveolar density is an age-sensitive characteristic of adipocytes.
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Affiliation(s)
- V. Hulstrøm
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - C. Prats
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - J. Vinten
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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Boqué N, de la Iglesia R, de la Garza AL, Milagro FI, Olivares M, Bañuelos Ó, Soria AC, Rodríguez-Sánchez S, Martínez JA, Campión J. Prevention of diet-induced obesity by apple polyphenols in Wistar rats through regulation of adipocyte gene expression and DNA methylation patterns. Mol Nutr Food Res 2013; 57:1473-8. [DOI: 10.1002/mnfr.201200686] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/17/2013] [Accepted: 02/11/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Noemi Boqué
- Department of Nutrition, Food Science; Physiology and Toxicology; University of Navarra; Pamplona; Spain
| | - Rocío de la Iglesia
- Department of Nutrition, Food Science; Physiology and Toxicology; University of Navarra; Pamplona; Spain
| | - Ana L. de la Garza
- Department of Nutrition, Food Science; Physiology and Toxicology; University of Navarra; Pamplona; Spain
| | | | - Mónica Olivares
- Discovery Laboratory, Health and Nutrition Department; Biosearch S.A.; Granada; Spain
| | - Óscar Bañuelos
- Discovery Laboratory, Health and Nutrition Department; Biosearch S.A.; Granada; Spain
| | - Ana Cristina Soria
- Department of Instrumental Analysis and Environmental Chemistry; Institute of General Organic Chemistry (CSIC); Madrid; Spain
| | - Sonia Rodríguez-Sánchez
- Department of Instrumental Analysis and Environmental Chemistry; Institute of General Organic Chemistry (CSIC); Madrid; Spain
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Maneschi E, Vignozzi L, Morelli A, Mello T, Filippi S, Cellai I, Comeglio P, Sarchielli E, Calcagno A, Mazzanti B, Vettor R, Vannelli GB, Adorini L, Maggi M. FXR activation normalizes insulin sensitivity in visceral preadipocytes of a rabbit model of MetS. J Endocrinol 2013; 218:215-31. [PMID: 23750014 DOI: 10.1530/joe-13-0109] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Insulin resistance is the putative key underlying mechanism linking adipose tissue (AT) dysfunction with liver inflammation and steatosis in metabolic syndrome (MetS). We have recently demonstrated that the selective farnesoid X receptor (FXR) agonist obeticholic acid (OCA) ameliorates insulin resistance and the metabolic profile with a marked reduction in the amount of visceral AT (VAT) in a high-fat diet (HFD)-induced rabbit model of MetS. These effects were mediated by the activation of FXR, since treatment with the selective TGR5 agonist INT-777 was not able to ameliorate the metabolic parameters evaluated. Herein, we report the effects of in vivo OCA dosing on the liver, the VAT, and the adipogenic capacity of VAT preadipocytes (rPADs) isolated from rabbits on a HFD compared with those on a control diet. VAT and liver were studied by immunohistochemistry, Western blot analysis, and RT-PCR. rPADs were exposed to a differentiating mixture to evaluate adipogenesis. Adipocyte size, hypoxia, and the expression of perilipin and cytosolic insulin-regulated glucose transporter GLUT4 (SLC2A4) were significantly increased in VAT isolated from the HFD rabbits, and normalized by OCA. The expression of steatosis and inflammation markers was increased in the liver of the HFD rabbits and normalized by OCA. rPADs isolated from the HFD rabbits were less sensitive to insulin, as demonstrated by the decreased insulin-induced glucose uptake, triglyceride synthesis, and adipogenic capacity, as well as by the impaired fusion of lipid droplets. OCA treatment preserved all the aforementioned metabolic functions. In conclusion, OCA dosing in a MetS rabbit model ameliorates liver and VAT functions. This could reflect the ability of OCA to restore insulin sensitivity in AT unable to finalize its storage function, counteracting MetS-induced metabolic alterations and pathological AT deposition.
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Affiliation(s)
- Elena Maneschi
- Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini 6, Florence, Italy
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Maneschi E, Morelli A, Filippi S, Cellai I, Comeglio P, Mazzanti B, Mello T, Calcagno A, Sarchielli E, Vignozzi L, Saad F, Vettor R, Vannelli GB, Maggi M. Testosterone treatment improves metabolic syndrome-induced adipose tissue derangements. J Endocrinol 2012; 215:347-62. [PMID: 23045189 DOI: 10.1530/joe-12-0333] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We recently demonstrated that testosterone dosing ameliorated the metabolic profile and reduced visceral adipose tissue (VAT) in a high-fat diet (HFD)-induced rabbit model of metabolic syndrome (MetS). We studied the effects of HFD and in vivo testosterone dosing on VAT function and the adipogenic capacity of rabbit preadipocytes isolated from VAT of regular diet (RD), HFD, and testosterone-treated HFD rabbits. VAT was studied by immunohistochemistry, western blot, and RT-PCR. Isolated rPADs were exposed to adipocyte differentiating mixture (DIM) to evaluate adipogenic potential. Adipocyte size was significantly increased in HFD VAT compared with RD, indicating adipocyte dysfunction, which was normalized by testosterone dosing. Accordingly, perilipin, an anti-lipolytic protein, was significantly increased in HFD VAT, when compared with other groups. HFD VAT was hypoxic, while testosterone dosing normalized VAT oxygenation. In VAT, androgen receptor expression was positively associated with mRNA expression of GLUT4 (SLC2A4) (insulin-regulated glucose transporter) and STAMP2 (STEAP4) (androgen-dependent gene required for insulin signaling). In testosterone-treated HFD VAT, STAMP2 mRNA was significantly increased when compared with the other groups. Moreover, GLUT4 membrane translocation was significantly reduced in HFD VAT, compared with RD, and increased by testosterone. In DIM-exposed preadipocytes from HFD, triglyceride accumulation, adipocyte-specific genes, insulin-stimulated triglyceride synthesis, glucose uptake, and GLUT4 membrane translocation were reduced compared with preadipocytes from RD and normalized by in vivo testosterone dosing. In conclusion, testosterone dosing in a MetS animal model positively affects VAT functions. This could reflect the ability of testosterone in restoring insulin sensitivity in VAT, thus counteracting metabolic alterations.
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Affiliation(s)
- Elena Maneschi
- Sexual Medicine and Andrology Unit, Department of Clinical Physiopathology, University of Florence, Viale Pieraccini, 6, Florence 50139, Italy
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Björnheden T, Jakubowicz B, Levin M, Odén B, Edén S, Sjöström L, Lönn M. Computerized Determination of Adipocyte Size. ACTA ACUST UNITED AC 2012; 12:95-105. [PMID: 14742847 DOI: 10.1038/oby.2004.13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Fat cell size is a fundamental parameter in the study of adipose tissue metabolism, because it markedly influences the cellular rates of metabolism. Previous techniques for the sizing of adipocytes are often complicated or time-consuming. The aim of this study was to develop a new, computerized method for rapid and accurate determination of adipocyte size in a cell suspension obtained by incubating human or rat adipose tissue biopsies with collagenase. RESEARCH METHODS AND PROCEDURES The cell suspension was placed between a siliconized glass slide and a cover slip. Using the reference method [designated as (R)], the cell diameters were determined manually using a microscope with a calibrated ocular. The new method presented here [designated as (C)] was based on computerized image analysis. RESULTS After two well-defined corrective adjustments, measurements with (R) and (C) agreed very well. The small remaining differences seemed, in fact, to depend on inconsistencies in (R). DISCUSSION We propose that (C) constitutes a valuable tool to study fat cell size, because this method is fast and allows the assessment of a sufficient number of cells to get reliable data on size distribution. Furthermore, images of cell preparations may be stored for future reference.
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Affiliation(s)
- Tom Björnheden
- Department of Internal Medicine, Göteborg University, Sahlgrenska University Hospital, Göteborg, Sweden
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Affiliation(s)
- Gale B. Carey
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, New Hampshire 03824, United States
| | - Lisa C. Merrill
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, New Hampshire 03824, United States
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A comparison of subcutaneous adipose tissue proteomes in juvenile piglets with a contrasted adiposity underscored similarities with human obesity. J Proteomics 2012; 75:949-61. [DOI: 10.1016/j.jprot.2011.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 10/13/2011] [Accepted: 10/19/2011] [Indexed: 01/15/2023]
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Meissburger B, Stachorski L, Röder E, Rudofsky G, Wolfrum C. Tissue inhibitor of matrix metalloproteinase 1 (TIMP1) controls adipogenesis in obesity in mice and in humans. Diabetologia 2011; 54:1468-79. [PMID: 21437772 DOI: 10.1007/s00125-011-2093-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 01/20/2011] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESIS Extracellular matrix reorganisation is a crucial step of adipocyte differentiation and is controlled by the matrix metalloproteinase-tissue inhibitor of matrix metalloproteinase (TIMP) enzyme system. We therefore sought to define the role of TIMP1 in adipogenesis and to elucidate whether upregulation of TIMP1 in obesity has direct effects on adipocyte formation. METHODS TIMP1 protein levels and mRNA were measured in lean and obese mice with a focus on levels in adipose tissue. We also analysed the effect of recombinant murine TIMP1 on adipogenesis, adipocyte size and metabolic control in vitro and in vivo. RESULTS TIMP1 levels were increased in the serum and adipose tissue of obese mouse models. Recombinant murine TIMP1 inhibited adipocyte differentiation in 3T3-L1 as well as in subcutaneous primary pre-adipocytes. Conversely, neutralising TIMP1 with a specific antibody enhanced adipocyte differentiation. In vivo, injection of recombinant TIMP1 in mice challenged with a high-fat diet led to enlarged adipocytes. TIMP1-treated mice developed an impaired metabolic profile with increased circulating NEFA levels, hepatic triacylglycerol accumulation and accelerated insulin resistance. Altered glucose clearance in TIMP1-injected mice was due to changes in adipose tissue glucose uptake, whereas muscle glucose clearance remained unaffected. CONCLUSIONS/INTERPRETATION TIMP1 is a negative regulator of adipogenesis. In vivo, TIMP1 leads to enlarged adipocytes in the state of overnutrition. This might contribute to the detrimental metabolic consequences seen in TIMP1-injected mice, such as systemic fatty acid overload, hepatic lipid accumulation and insulin resistance.
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Affiliation(s)
- B Meissburger
- Swiss Federal Institute of Technology, ETH Zürich, Institute for ETH Zürich, Food Nutrition and Health, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
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Wasserman DH, Cherrington AD. Regulation of Extramuscular Fuel Sources During Exercise. Compr Physiol 2011. [DOI: 10.1002/cphy.cp120123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Liu A, Sonmez A, Yee G, Bazuine M, Arroyo M, Sherman A, McLaughlin T, Reaven G, Cushman S, Tsao P. Differential adipogenic and inflammatory properties of small adipocytes in Zucker Obese and Lean rats. Diab Vasc Dis Res 2010; 7:311-8. [PMID: 20961992 PMCID: PMC3462589 DOI: 10.1177/1479164110386126] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
We recently reported that a preponderance of small adipose cells, decreased expression of cell differentiation markers, and enhanced inflammatory activity in human subcutaneous whole adipose tissue were associated with insulin resistance. To test the hypothesis that small adipocytes exhibited these differential properties, we characterised small adipocytes from epididymal adipose tissue of Zucker Obese (ZO) and Lean (ZL) rats. Rat epididymal fat pads were removed and adipocytes isolated by collagenase digestion. Small adipocytes were separated by sequential filtration through nylon meshes. Adipocytes were fixed in osmium tetroxide for cell size distribution analysis via Beckman Coulter Multisizer. Quantitative real-time PCR for cell differentiation and inflammatory genes was performed. Small adipocytes represented a markedly greater percentage of the total adipocyte population in ZO than ZL rats (58±4% vs. 12±3%, p<0.001). In ZO rats, small as compared with total adipocytes had 4-fold decreased adiponectin, and 4-fold increased visfatin and IL-6 levels. Comparison of small adipocytes in ZO versus ZL rats revealed 3-fold decreased adiponectin and PPARγ levels, and 2.5-fold increased IL-6. In conclusion, ZO rat adipose tissue harbours a large proportion of small adipocytes that manifest impaired cell differentiation and pro-inflammatory activity, two mechanisms by which small adipocytes may contribute to insulin resistance.
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Affiliation(s)
- Alice Liu
- Division of Endocrinology, Department of Medicine, Stanford University Medical Center, CA 94305, USA.
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Varlamov O, Somwar R, Cornea A, Kievit P, Grove KL, Roberts CT. Single-cell analysis of insulin-regulated fatty acid uptake in adipocytes. Am J Physiol Endocrinol Metab 2010; 299:E486-96. [PMID: 20570821 PMCID: PMC2944284 DOI: 10.1152/ajpendo.00330.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Increased body fat correlates with the enlargement of average fat cell size and reduced adipose tissue insulin sensitivity. It is currently unclear whether adipocytes, as they accumulate more triglycerides and grow in size, gradually become less insulin sensitive or whether obesity-related factors independently cause both the enlargement of adipocyte size and reduced adipose tissue insulin sensitivity. In the first instance, large and small adipocytes in the same tissue would exhibit differences in insulin sensitivity, whereas, in the second instance, adipocyte size per se would not necessarily correlate with insulin response. To analyze the effect of adipocyte size on insulin sensitivity, we employed a new single-cell imaging assay that resolves fatty acid uptake and insulin response in single adipocytes in subcutaneous adipose tissue explants. Here, we report that subcutaneous adipocytes are heterogeneous in size and intrinsic insulin sensitivity. Whereas smaller adipocytes respond to insulin by increasing lipid uptake, adipocytes with cell diameters larger than 80-100 microm are insulin resistant. We propose that, when cell size approaches a critical boundary, adipocytes lose insulin-dependent fatty acid transport. This negative feedback mechanism may protect adipocytes from lipid overload and restrict further expansion of adipose tissue, which leads to obesity and metabolic complications.
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Affiliation(s)
- Oleg Varlamov
- Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, 97006, USA
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Turner N, Hariharan K, TidAng J, Frangioudakis G, Beale SM, Wright LE, Zeng XY, Leslie SJ, Li JY, Kraegen EW, Cooney GJ, Ye JM. Enhancement of muscle mitochondrial oxidative capacity and alterations in insulin action are lipid species dependent: potent tissue-specific effects of medium-chain fatty acids. Diabetes 2009; 58:2547-54. [PMID: 19720794 PMCID: PMC2768163 DOI: 10.2337/db09-0784] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Medium-chain fatty acids (MCFAs) have been reported to be less obesogenic than long-chain fatty acids (LCFAs); however, relatively little is known regarding their effect on insulin action. Here, we examined the tissue-specific effects of MCFAs on lipid metabolism and insulin action. RESEARCH DESIGN AND METHODS C57BL6/J mice and Wistar rats were fed either a low-fat control diet or high-fat diets rich in MCFAs or LCFAs for 4-5 weeks, and markers of mitochondrial oxidative capacity, lipid levels, and insulin action were measured. RESULTS Mice fed the MCFA diet displayed reduced adiposity and better glucose tolerance than LCFA-fed animals. In skeletal muscle, triglyceride levels were increased by the LCFA diet (77%, P < 0.01) but remained at low-fat diet control levels in the MCFA-fed animals. The LCFA diet increased (20-50%, P < 0.05) markers of mitochondrial metabolism in muscle compared with low-fat diet-fed controls; however; the increase in oxidative capacity was substantially greater in MCFA-fed animals (50-140% versus low-fat-fed controls, P < 0.01). The MCFA diet induced a greater accumulation of liver triglycerides than the LCFA diet, likely due to an upregulation of several lipogenic enzymes. In rats, isocaloric feeding of MCFA or LCFA high-fat diets induced hepatic insulin resistance to a similar degree; however, insulin action was preserved at the level of low-fat diet-fed controls in muscle and adipose from MCFA-fed animals. CONCLUSIONS MCFAs reduce adiposity and preserve insulin action in muscle and adipose, despite inducing steatosis and insulin resistance in the liver. Dietary supplementation with MCFAs may therefore be beneficial for preventing obesity and peripheral insulin resistance.
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Affiliation(s)
- Nigel Turner
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
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Summermatter S, Marcelino H, Arsenijevic D, Buchala A, Aprikian O, Assimacopoulos-Jeannet F, Seydoux J, Montani JP, Solinas G, Dulloo AG. Adipose tissue plasticity during catch-up fat driven by thrifty metabolism: relevance for muscle-adipose glucose redistribution during catch-up growth. Diabetes 2009; 58:2228-37. [PMID: 19602538 PMCID: PMC2750217 DOI: 10.2337/db08-1793] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Catch-up growth, a risk factor for later type 2 diabetes, is characterized by hyperinsulinemia, accelerated body-fat recovery (catch-up fat), and enhanced glucose utilization in adipose tissue. Our objective was to characterize the determinants of enhanced glucose utilization in adipose tissue during catch-up fat. RESEARCH DESIGN AND METHODS White adipose tissue morphometry, lipogenic capacity, fatty acid composition, insulin signaling, in vivo glucose homeostasis, and insulinemic response to glucose were assessed in a rat model of semistarvation-refeeding. This model is characterized by glucose redistribution from skeletal muscle to adipose tissue during catch-up fat that results solely from suppressed thermogenesis (i.e., without hyperphagia). RESULTS Adipose tissue recovery during the dynamic phase of catch-up fat is accompanied by increased adipocyte number with smaller diameter, increased expression of genes for adipogenesis and de novo lipogenesis, increased fatty acid synthase activity, increased proportion of saturated fatty acids in triglyceride (storage) fraction but not in phospholipid (membrane) fraction, and no impairment in insulin signaling. Furthermore, it is shown that hyperinsulinemia and enhanced adipose tissue de novo lipogenesis occur concomitantly and are very early events in catch-up fat. CONCLUSIONS These findings suggest that increased adipose tissue insulin stimulation and consequential increase in intracellular glucose flux play an important role in initiating catch-up fat. Once activated, the machinery for lipogenesis and adipogenesis contribute to sustain an increased insulin-stimulated glucose flux toward fat storage. Such adipose tissue plasticity could play an active role in the thrifty metabolism that underlies glucose redistribution from skeletal muscle to adipose tissue.
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Affiliation(s)
- Serge Summermatter
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Helena Marcelino
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Denis Arsenijevic
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Antony Buchala
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | | | - Josiane Seydoux
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jean-Pierre Montani
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Giovanni Solinas
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Abdul G. Dulloo
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
- Corresponding author: A.G. Dulloo,
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38
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Association of serum amyloid A levels with adipocyte size and serum levels of adipokines: differences between men and women. Cytokine 2009; 48:260-6. [PMID: 19758820 DOI: 10.1016/j.cyto.2009.08.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 06/17/2009] [Accepted: 08/18/2009] [Indexed: 11/24/2022]
Abstract
The aim of this study was to characterize the association between adipocyte enlargement and circulating levels of serum amyloid A (SAA). Furthermore, we wanted to search for possible associations with measures of glycemic control and levels of circulating adipokines and/or inflammatory markers in men and women with a large range in body mass index. The study cohort consisted of 167 subjects, 114 non-diabetic and 53 with Type 2 diabetes. Adipocyte diameter as well as circulating levels of SAA, C-reactive protein (CRP), adiponectin, leptin, interleukin-6, tumor necrosis factor alpha, glucose and insulin were measured. Women had higher serum levels of SAA than men (p=0.044). SAA levels were weakly but positively correlated with BMI (p=0.043) and % body fat (p=0.027) in all subjects as well as subcutaneous adipocyte diameter (p=0.034) in women. Furthermore, in all subjects we found correlations between SAA levels and levels of CRP (p<0.001), interleukin-6 (p<0.001), leptin (p=0.003), insulin (p=0.006), HbA1c (p=0.02) and HOMA-IR (p=0.002). A majority of the correlations were strongest in women. In conclusion, serum levels of SAA are strongly correlated with serum levels of inflammatory markers as well as measures of glycemic control. There seems to be large sex differences in these associations suggesting that sex-specific factors need to be considered when analyzing SAA levels in relation to metabolic disease.
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39
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Lönn M, Mehlig K, Bengtsson C, Lissner L. Adipocyte size predicts incidence of type 2 diabetes in women. FASEB J 2009; 24:326-31. [PMID: 19741173 DOI: 10.1096/fj.09-133058] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Enlarged subcutaneous abdominal adipocytes have been shown to predict incidence of type 2 diabetes (T2D) in the Pima population of Arizona (USA). We investigated the role of subcutaneous abdominal adipocyte size (AAS), as well as femoral adipocyte size (FAS), as predictors of T2D in a population-based Swedish cohort. In 1974-1975, a sample of 1302 middle-aged women underwent a health examination, including anthropometry and evaluation of parental medical history. In addition, body composition (total body potassium and total body water), AAS and FAS (adipose tissue needle biopsy) were assessed in a subsample of 245 women. Incidence of T2D was followed until 2001, with 36 cases eligible for inclusion in this analysis. Women developing T2D had larger AAS at baseline vs. women remaining healthy (age/heredity-adjusted hazard ratio for increase of AAS by 1 sd [AAS-HR] 1.91; P<0.001). Further adjustment for both body fat percentage and waist-to-height ratio (WHtR) indicated a robust association. For FAS, the corresponding associations were consistently weaker. WHtR retained a strong predictive association independent of AAS and FAS (WHtR-HR 2.6 and 2.7, respectively; P<0.001). To conclude, in addition to the amount and distribution of body fat in women, subcutaneous adipocyte size, particularly in the abdominal region, predicts incidence of T2D in later life.
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Affiliation(s)
- Malin Lönn
- Department of Clinical Chemistry, Sahlgrenska University Hospital, Bruna stråket 16, Gothenburg, Sweden.
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40
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Varady KA, Tussing L, Bhutani S, Braunschweig CL. Degree of weight loss required to improve adipokine concentrations and decrease fat cell size in severely obese women. Metabolism 2009; 58:1096-101. [PMID: 19477470 DOI: 10.1016/j.metabol.2009.04.010] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 04/07/2009] [Accepted: 04/08/2009] [Indexed: 11/22/2022]
Abstract
Adipose tissue physiology plays an important role in mediating disease risk. Weight loss in obese individuals improves indicators of adipocyte physiology. However, the minimum degree of weight loss required to elicit improvements remains unknown. The objective of the present study was to determine the minimum weight loss required to improve adipokine profile and decrease fat cell size in severely obese women. Thirteen severely obese women (body mass index, 50 +/- 3 kg/m(2); age, 35 +/- 1 years) consumed a low-calorie diet for 3 weeks with the goal of losing 5% of their initial weight. Subjects were divided into 2 weight loss groups posttreatment: less than 5% weight loss and 5% to 10% weight loss. Body weight was reduced (P < .05) in both groups (-1.4 +/- 1.0 and -6.8 +/- 0.6 kg, respectively). Adiponectin concentrations increased (P < .05) by 20% in the 5% to 10% weight loss group only. Likewise, leptin and resistin decreased (P < .05) by 37% and 27%, respectively, in the group that lost more weight. Visceral and subcutaneous fat cell size was 41% and 37% smaller (P < .01), respectively, in the 5% to 10% weight loss group. Smaller visceral adipocyte size was related to lower insulin (r = 0.82, P = .01) and glucose (r = 0.58, P = .04) concentrations posttreatment. These findings suggest that a minimum weight loss of 5% is required to improve adipokine profile and decrease fat cell size in severely obese women. These changes in adipocyte physiology may be linked to reductions in metabolic disease risk in this population.
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Affiliation(s)
- Krista A Varady
- Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, USA.
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41
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Takano-Murakami R, Tokunaga K, Kondo N, Ito T, Kitahara H, Ito M, Endo N. Glucocorticoid inhibits bone regeneration after osteonecrosis of the femoral head in aged female rats. TOHOKU J EXP MED 2009; 217:51-8. [PMID: 19155608 DOI: 10.1620/tjem.217.51] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Idiopathic osteonecrosis of the femoral head (ION) is a painful disease of the hip, the pathogenic mechanism of which is still unclear. The most common extraneous factor is steroid treatment. Steroids have inhibiting effects on bone formation and resorption. When bone regenerative treatments are indicated for ION patients who are exposed to steroids, we cannot ignore the effects of corticosteroid itself on bone healing. The aim of this study was to investigate the effects of glucocorticoid on bone regeneration after osteonecrosis of the femoral head in a rat model. Osteonecrosis was induced surgically on the left femoral heads of aged female rats (about 6 months old) on day 0. Methylprednisolone sodium succinate (MPSS) or normal saline was administrated at a dose of 100 mg/kg/day from day 7 to 11. Femoral heads were analyzed histologically. There were no pathological findings in the right femoral heads of the MPSS-treated and saline-treated rats, as control for the contralateral injury. The newly formed bone volume and the osteoclast number were significantly smaller in the MPSS-treated group. The normal bone marrow was regenerated in the saline-treated group, whereas most of the bone marrow space still contained fibroblast-like spindle-shaped cells in the MPSS-treated group on day 42. Alkaline phosphatase-positive cells were only seen in the areas around the regenerated bone marrow cavities. Thus, MPSS inhibits bone formation by suppressing osteoblast proliferation and resorption by suppressing the recruitment of osteoclast precursors. These findings may be useful when designing treatments for ION patients exposed to steroids.
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Affiliation(s)
- Reiko Takano-Murakami
- Department of Regenerative and Transplant Medicine, Division of Orthopedic Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
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42
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Yin J, Gao Z, He Q, Zhou D, Guo Z, Ye J. Role of hypoxia in obesity-induced disorders of glucose and lipid metabolism in adipose tissue. Am J Physiol Endocrinol Metab 2009; 296:E333-42. [PMID: 19066318 PMCID: PMC2645021 DOI: 10.1152/ajpendo.90760.2008] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Recent studies suggest that adipose tissue hypoxia (ATH) may contribute to endocrine dysfunction in adipose tissue of obese mice. In this study, we examined hypoxia's effects on metabolism in adipocytes. We determined the dynamic relationship of ATH and adiposity in ob/ob mice. The interstitial oxygen pressure (Po(2)) was monitored in the epididymal fat pads for ATH. During weight gain from 39.5 to 55.5 g, Po(2) declined from 34.8 to 20.1 mmHg, which are 40-60% lower than those in the lean mice. Insulin receptor-beta (IRbeta) and insulin receptor substrate-1 (IRS-1) were decreased in the adipose tissue of obese mice, and the alteration was observed in 3T3-L1 adipocytes after hypoxia (1% oxygen) treatment. Insulin-induced glucose uptake and Akt Ser(473) phosphorylation was blocked by hypoxia in the adipocytes. This effect of hypoxia exhibited cell type specificity, as it was not observed in L6 myotubes and betaTC6 cells. In response to hypoxia, free fatty acid (FFA) uptake was reduced and lipolysis was increased in 3T3-L1 adipocytes. The molecular mechanism of decreased fatty acid uptake may be related to inhibition of fatty acid transporters (FATP1 and CD36) and transcription factors (PPARgamma and C/EBPalpha) by hypoxia. The hypoxia-induced lipolysis was observed in vivo after femoral arterial clamp. Necrosis and apoptosis were induced by hypoxia in 3T3-L1 adipocytes. These data suggest that ATH may promote FFA release and inhibit glucose uptake in adipocytes by inhibition of the insulin-signaling pathway and induction of cell death.
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Affiliation(s)
- Jun Yin
- Pennington Biomedical Research Center, Louisiana State Univ. System, 6400 Perkins Rd., Baton Rouge, LA 70808, USA
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43
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Adipocyte volumes and levels of adipokines in diabetes and obesity. Diabetes & Metabolic Syndrome: Clinical Research & Reviews 2008. [DOI: 10.1016/j.dsx.2008.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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44
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Franck N, Stenkula KG, Ost A, Lindström T, Strålfors P, Nystrom FH. Insulin-induced GLUT4 translocation to the plasma membrane is blunted in large compared with small primary fat cells isolated from the same individual. Diabetologia 2007; 50:1716-22. [PMID: 17572871 DOI: 10.1007/s00125-007-0713-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 04/12/2007] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS Several studies have suggested that large fat cells are less responsive to insulin than small fat cells. However, in these studies, large fat cells from obese individuals were compared with smaller fat cells from leaner participants, in effect making it impossible to draw conclusions about whether there is a causal relationship between fat cell size and insulin sensitivity. We hypothesised that small fat cells might be more insulin-responsive than large adipocytes when obtained from the same individual. MATERIALS AND METHODS We developed a method of sorting isolated primary human fat cells by using nylon filters of two different pore sizes. The cells were stained to visualise DNA, which allowed discrimination from artefacts such as lipid droplets. The sorted cells were left to recover overnight, since we had previously demonstrated that this is necessary for correct assessment of insulin response. RESULTS We found similar amounts of the insulin receptor (IR), IRS-1 and GLUT4 when we compared small and large adipocytes from the same volunteer by immunoblotting experiments using the same total cell volume from both cell populations. Activation of IR, IRS-1 and Akt1 (also known as protein kinase B) by insulin was similar in the two cell populations. However, immunofluorescence confocal microscopy of plasma membrane sheets did not reveal any increase in the amount of GLUT4 in the plasma membrane following insulin stimulation in the large fat cells, whereas we saw a twofold increase in the amount of GLUT4 in the small fat cells. CONCLUSIONS/INTERPRETATION Our results support a causal relationship between the accumulation of large fat cells in obese individuals and reduced insulin responsiveness.
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Affiliation(s)
- N Franck
- Department of Medicine and Care, Linkoping University, Linkoping, Sweden
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45
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Jernås M, Palming J, Sjöholm K, Jennische E, Svensson PA, Gabrielsson BG, Levin M, Sjögren A, Rudemo M, Lystig TC, Carlsson B, Carlsson LMS, Lönn M. Separation of human adipocytes by size: hypertrophic fat cells display distinct gene expression. FASEB J 2006; 20:1540-2. [PMID: 16754744 DOI: 10.1096/fj.05-5678fje] [Citation(s) in RCA: 312] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Enlarged adipocytes are associated with insulin resistance and are an independent predictor of type 2 diabetes. To understand the molecular link between these diseases and adipocyte hypertrophy, we developed a technique to separate human adipocytes from an adipose tissue sample into populations of small cells (mean 57.6+/-3.54 microm) and large cells (mean 100.1+/-3.94 microm). Microarray analysis of the cell populations separated from adipose tissue from three subjects identified 14 genes, of which five immune-related, with more than fourfold higher expression in large cells than small cells. Two of these genes were serum amyloid A (SAA) and transmembrane 4 L six family member 1 (TM4SF1). Real-time RT-PCR analysis of SAA and TM4SF1 expression in adipocytes from seven subjects revealed 19-fold and 22-fold higher expression in the large cells, respectively, and a correlation between adipocyte size and both SAA and TM4SF1 expression. The results were verified using immunohistochemistry. In comparison with 17 other human tissues and cell types by microarray, large adipocytes displayed by far the highest SAA and TM4SF1 expression. Thus, we have identified genes with markedly higher expression in large, compared with small, human adipocytes. These genes may link hypertrophic obesity to insulin resistance/type 2 diabetes.
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Affiliation(s)
- Margareta Jernås
- Research Centre for Endocrinology and Metabolism, Division of Body Composition and Metabolism, Department of Internal Medicine, Vita Stråket 15, SE 413 45 Göteborg, Sweden
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46
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Bays H, Dujovne CA. Adiposopathy is a more rational treatment target for metabolic disease than obesity alone. Curr Atheroscler Rep 2006; 8:144-56. [PMID: 16510049 DOI: 10.1007/s11883-006-0052-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Current guidelines recommend that weight-loss therapy should be primarily based upon specific body mass index (BMI) cut-off limits. However, in the adipocentric paradigm, it is acknowledged that co-morbidities, such as type 2 diabetes mellitus, hypertension, and dyslipidemia, occur at all levels of BMI. Excessive fat mass (adiposity) in genetically susceptible individuals results in fat dysfunction (adiposopathy), which then contributes to metabolic disorders that increase the risk of atherosclerotic cardiovascular disease. In this paradigm, the term "anti-obesity" treatment might best be replaced by "anti-adiposopathy" treatment, wherein the focus is not based solely on BMI, but instead directed towards physiologically improving fat cell function and clinically improving the metabolic health of patients. This may occur through appropriate diet, physical exercise, and other lifestyle changes, and/or from drug therapies. Cannabinoid receptor antagonists and peroxisome proliferator activated receptor agonists are examples of agents that physiologically improve fat function and clinically improve metabolic disease.
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Affiliation(s)
- Harold Bays
- L-MARC Research Center, 3288 Illinois Avenue, Louisville, KY 40213, USA.
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47
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Weisberg SP, McCann D, Desai M, Rosenbaum M, Leibel RL, Ferrante AW. Obesity is associated with macrophage accumulation in adipose tissue. J Clin Invest 2004; 112:1796-808. [PMID: 14679176 PMCID: PMC296995 DOI: 10.1172/jci19246] [Citation(s) in RCA: 3517] [Impact Index Per Article: 175.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Obesity alters adipose tissue metabolic and endocrine function and leads to an increased release of fatty acids, hormones, and proinflammatory molecules that contribute to obesity associated complications. To further characterize the changes that occur in adipose tissue with increasing adiposity, we profiled transcript expression in perigonadal adipose tissue from groups of mice in which adiposity varied due to sex, diet, and the obesity-related mutations agouti (Ay) and obese (Lepob). We found that the expression of 1,304 transcripts correlated significantly with body mass. Of the 100 most significantly correlated genes, 30% encoded proteins that are characteristic of macrophages and are positively correlated with body mass. Immunohistochemical analysis of perigonadal, perirenal, mesenteric, and subcutaneous adipose tissue revealed that the percentage of cells expressing the macrophage marker F4/80 (F4/80+) was significantly and positively correlated with both adipocyte size and body mass. Similar relationships were found in human subcutaneous adipose tissue stained for the macrophage antigen CD68. Bone marrow transplant studies and quantitation of macrophage number in adipose tissue from macrophage-deficient (Csf1op/op) mice suggest that these F4/80+ cells are CSF-1 dependent, bone marrow-derived adipose tissue macrophages. Expression analysis of macrophage and nonmacrophage cell populations isolated from adipose tissue demonstrates that adipose tissue macrophages are responsible for almost all adipose tissue TNF-alpha expression and significant amounts of iNOS and IL-6 expression. Adipose tissue macrophage numbers increase in obesity and participate in inflammatory pathways that are activated in adipose tissues of obese individuals.
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Affiliation(s)
- Stuart P Weisberg
- Division of Moleuclar Genetics, Department of Pediatrics, Columbia University, New York, New York 10032, USA
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48
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Weisberg SP, McCann D, Desai M, Rosenbaum M, Leibel RL, Ferrante AW. Obesity is associated with macrophage accumulation in adipose tissue. J Clin Invest 2003. [DOI: 10.1172/jci200319246] [Citation(s) in RCA: 6528] [Impact Index Per Article: 310.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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49
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Xavier AR, Garófalo MAR, Migliorini RH, Kettelhut IC. Dietary sodium restriction exacerbates age-related changes in rat adipose tissue and liver lipogenesis. Metabolism 2003; 52:1072-7. [PMID: 12898476 DOI: 10.1016/s0026-0495(03)00162-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To investigate the effects of prolonged dietary sodium restriction on lipid metabolism, male rats weighing 35 to 40 g (just weaned) were fed either a low-salt (LSD) or a normal salt diet (NSD) and used in metabolic experiments after 1, 2, or 3 months of diet consumption. After 2 and 3 months on the diet, LSD rats showed increased amounts of lipid in carcass and retroperitoneal tissue. In both LSD and NSD, extending the feeding period from 2 to 3 months resulted in a marked reduction in the in vivo rates of adipose tissue fatty acid synthesis that was accompanied by increases in liver lipogenesis and in the activity of adipose tissue lipoprotein lipase (LPL). However, these increases were more marked in LSD rats. Thus, in vivo rates of liver fatty synthesis and LPL activity in LSD rats, which were already higher (by about 35% and 20%, respectively) than in controls after 2 months, attained levels 50% higher than those in NSD animals after another month on the diet. Brown adipose tissue (BAT) thermogenic capacity, estimated after 2 and 3 months by the tissue temperature response to norepinephrine (NE) injection and by guanosine diphosphate (GDP) binding to BAT mitochondria, did not change in controls, but was significantly reduced in LSD rats. This raises the possibility that a decrease in overall energy expenditure, together with an LPL-induced increased uptake of preformed fatty acids from the circulation, may account for the excessive lipid accumulation in LSD rats. Taken together, the data indicate that prolonged dietary sodium restriction exacerbates normal, age-related changes in white and BAT metabolism.
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Affiliation(s)
- A R Xavier
- Department of Biochemistry and Immunology, School of Medicine, University of São Paulo, São Paulo, Brasil
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50
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Seraphim PM, Nunes MT, Machado UF. GLUT4 protein expression in obese and lean 12-month-old rats: insights from different types of data analysis. Braz J Med Biol Res 2001; 34:1353-62. [PMID: 11593313 DOI: 10.1590/s0100-879x2001001000018] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
GLUT4 protein expression in white adipose tissue (WAT) and skeletal muscle (SM) was investigated in 2-month-old, 12-month-old spontaneously obese or 12-month-old calorie-restricted lean Wistar rats, by considering different parameters of analysis, such as tissue and body weight, and total protein yield of the tissue. In WAT, an approximately 70% decrease was observed in plasma membrane and microsomal GLUT4 protein, expressed as microg protein or g tissue, in both 12-month-old obese and 12-month-old lean rats compared to 2-month-old rats. However, when plasma membrane and microsomal GLUT4 tissue contents were expressed as g body weight, they were the same. In SM, GLUT4 protein content, expressed as microg protein, was similar in 2-month-old and 12-month-old obese rats, whereas it was reduced in 12-month-old obese rats, when expressed as g tissue or g body weight, which may play an important role in insulin resistance. Weight loss did not change the SM GLUT4 content. These results show that altered insulin sensitivity is accompanied by modulation of GLUT4 protein expression. However, the true role of WAT and SM GLUT4 contents in whole-body or tissue insulin sensitivity should be determined considering not only GLUT4 protein expression, but also the strong morphostructural changes in these tissues, which require different types of data analysis.
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Affiliation(s)
- P M Seraphim
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
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