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Wilhelmsen A, Stephens FB, Bennett AJ, Karagounis LG, Jones SW, Tsintzas K. Skeletal muscle myostatin mRNA expression is upregulated in aged human adults with excess adiposity but is not associated with insulin resistance and ageing. GeroScience 2024; 46:2033-2049. [PMID: 37801203 PMCID: PMC10828472 DOI: 10.1007/s11357-023-00956-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 09/20/2023] [Indexed: 10/07/2023] Open
Abstract
Myostatin negatively regulates skeletal muscle growth and appears upregulated in human obesity and associated with insulin resistance. However, observations are confounded by ageing, and the mechanisms responsible are unknown. The aim of this study was to delineate between the effects of excess adiposity, insulin resistance and ageing on myostatin mRNA expression in human skeletal muscle and to investigate causative factors using in vitro models. An in vivo cross-sectional analysis of human skeletal muscle was undertaken to isolate effects of excess adiposity and ageing per se on myostatin expression. In vitro studies employed human primary myotubes to investigate the potential involvement of cross-talk between subcutaneous adipose tissue (SAT) and skeletal muscle, and lipid-induced insulin resistance. Skeletal muscle myostatin mRNA expression was greater in aged adults with excess adiposity than age-matched adults with normal adiposity (2.0-fold higher; P < 0.05) and occurred concurrently with altered expression of genes involved in the maintenance of muscle mass but did not differ between younger and aged adults with normal adiposity. Neither chronic exposure to obese SAT secretome nor acute elevation of fatty acid availability (which induced insulin resistance) replicated the obesity-mediated upregulation of myostatin mRNA expression in vitro. In conclusion, skeletal muscle myostatin mRNA expression is uniquely upregulated in aged adults with excess adiposity and insulin resistance but not by ageing alone. This does not appear to be mediated by the SAT secretome or by lipid-induced insulin resistance. Thus, factors intrinsic to skeletal muscle may be responsible for the obesity-mediated upregulation of myostatin, and future work to establish causality is required.
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Affiliation(s)
- Andrew Wilhelmsen
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | | | - Andrew J Bennett
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Leonidas G Karagounis
- Mary MacKillop Institute for Health Research (MMIHR), Melbourne, Australian Catholic University, Melbourne, Australia
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Simon W Jones
- Institute of Inflammation and Ageing, MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, Queen Elizabeth Hospital, The University of Birmingham, Birmingham, UK
| | - Kostas Tsintzas
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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Goodpaster BH, Bergman BC, Brennan AM, Sparks LM. Intermuscular adipose tissue in metabolic disease. Nat Rev Endocrinol 2022; 19:285-298. [PMID: 36564490 DOI: 10.1038/s41574-022-00784-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/21/2022] [Indexed: 12/24/2022]
Abstract
Intermuscular adipose tissue (IMAT) is a distinct adipose depot described in early reports as a 'fatty replacement' or 'muscle fat infiltration' that was linked to ageing and neuromuscular disease. Later studies quantifying IMAT with modern in vivo imaging methods (computed tomography and magnetic resonance imaging) revealed that IMAT is proportionately higher in men and women with type 2 diabetes mellitus and the metabolic syndrome than in people without these conditions and is associated with insulin resistance and poor physical function with ageing. In parallel, agricultural research has provided extensive insight into the role of IMAT and other muscle lipids in muscle (that is, meat) quality. In addition, studies using rodent models have shown that IMAT is a bona fide white adipose tissue depot capable of robust triglyceride storage and turnover. Insight into the importance of IMAT in human biology has been limited by the dearth of studies on its biological properties, that is, the quality of IMAT. However, in the past few years, investigations have begun to determine that IMAT has molecular and metabolic features that distinguish it from other adipose tissue depots. These studies will be critical to further decipher the role of IMAT in health and disease and to better understand its potential as a therapeutic target.
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Affiliation(s)
| | - Bryan C Bergman
- Division of Endocrinology, Diabetes, and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Andrea M Brennan
- Translational Research Institute, AdventHealth, Orlando, FL, USA
| | - Lauren M Sparks
- Translational Research Institute, AdventHealth, Orlando, FL, USA
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3
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Bolam SM, Konar S, Park YE, Callon KE, Workman J, Monk AP, Coleman B, Cornish J, Vickers MH, Munro JT, Musson DS. A high-fat diet has negative effects on tendon resident cells in an in vivo rat model. INTERNATIONAL ORTHOPAEDICS 2022; 46:1181-1190. [PMID: 35201374 PMCID: PMC9001221 DOI: 10.1007/s00264-022-05340-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 02/04/2022] [Indexed: 12/01/2022]
Abstract
BACKGROUND Tendinopathy is a major complication of diet-induced obesity. However, the effects of a high-fat diet (HFD) on tendon have not been well characterised. We aimed to determine: [1] the impact of a HFD on tendon properties and gene expression; and [2] whether dietary transition to a control diet (CD) could restore normal tendon health. METHODS Sprague-Dawley rats were randomised into three groups from weaning and fed either a: CD, HFD or HFD for 12 weeks and then CD thereafter (HF-CD). Biomechanical, histological and structural evaluation of the Achilles tendon was performed at 17 and 27 weeks of age. Tail tenocytes were isolated with growth rate and collagen production determined. Tenocytes and activated THP-1 cells were exposed to conditioned media (CM) of visceral adipose tissue explants, and gene expression was analysed. RESULTS There were no differences in the biomechanical, histological or structural tendon properties between groups. However, tenocyte growth and collagen production were increased in the HFD group at 27 weeks. There was lower SOX-9 expression in the HFD and HF-CD groups at 17 weeks and higher expression of collagen-Iα1 and matrix metalloproteinase-13 in the HFD group at 27 weeks. THP-1 cells exposed to adipose tissue CM from animals fed a HFD or HF-CD had lower expression of Il-10 and higher expression of Il-1β. CONCLUSIONS In this rodent model, a HFD negatively altered tendon cell characteristics. Dietary intervention restored some gene expression changes; however, adipose tissue secretions from the HF-CD group promoted an increased inflammatory state in macrophages. These changes may predispose tendon to injury and adverse events later in life.
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Affiliation(s)
- Scott M Bolam
- Department of Medicine, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
- Department of Orthopedic Surgery, Auckland City Hospital, 2 Park Road, Grafton, Auckland, New Zealand
| | - Subhajit Konar
- Department of Medicine, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
| | - Young-Eun Park
- Department of Medicine, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
| | - Karen E Callon
- Department of Medicine, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
| | - Josh Workman
- Chemical and Materials Engineering, University of Auckland, 5 Grafton Rd, Auckland, New Zealand
| | - A Paul Monk
- Department of Orthopedic Surgery, Auckland City Hospital, 2 Park Road, Grafton, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, 70 Symonds St, Grafton, Auckland, New Zealand
| | - Brendan Coleman
- Department of Orthopedic Surgery, Middlemore Hospital, 100 Hospital Road, Otahuhu, Auckland, New Zealand
| | - Jillian Cornish
- Department of Medicine, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
| | - Mark H Vickers
- Liggins Institute, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
| | - Jacob T Munro
- Department of Medicine, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand
- Department of Orthopedic Surgery, Auckland City Hospital, 2 Park Road, Grafton, Auckland, New Zealand
| | - David S Musson
- Department of Medicine, University of Auckland, 85 Park Road, Grafton, Auckland, New Zealand.
- Department of Nutrition & Dietetics, University of Auckland, 85 Park Road, Grafton, 1023, Auckland, New Zealand.
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Sparks LM, Goodpaster BH, Bergman BC. The Metabolic Significance of Intermuscular Adipose Tissue: Is IMAT a Friend or a Foe to Metabolic Health? Diabetes 2021; 70:2457-2467. [PMID: 34711670 DOI: 10.2337/dbi19-0006] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 08/27/2021] [Indexed: 12/25/2022]
Abstract
Adipose tissues are not homogeneous and show site-specific properties. An elusive and understudied adipose tissue depot, most likely due to its limited accessibility, is the intermuscular adipose tissue (IMAT) depot. Adipose tissue is a pliable organ with the ability to adapt to its physiological context, yet whether that adaptation is harmful or beneficial in the IMAT depot remains to be explored in humans. Potential reasons for IMAT accumulation in humans being deleterious or beneficial include 1) sex and related circulating hormone levels, 2) race and ethnicity, and 3) lifestyle factors (e.g., diet and physical activity level). IMAT quantity per se may not be the driving factor in the etiology of insulin resistance and type 2 diabetes, but rather the quality of the IMAT itself is the true puppeteer. Adipose tissue quality likely influences its secreted factors, which are also likely to influence metabolism of surrounding tissues. The advent of molecular assessments such as transcriptome sequencing (RNAseq), assay for transposase-accessible chromatin using sequencing (ATACseq), and DNA methylation at the single-cell and single-nucleus levels, as well as the potential for ultrasound-guided biopsies specifically for IMAT, will permit more sophisticated investigations of human IMAT and dramatically advance our understanding of this enigmatic adipose tissue.
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Wueest S, Konrad D. The controversial role of IL-6 in adipose tissue on obesity-induced dysregulation of glucose metabolism. Am J Physiol Endocrinol Metab 2020; 319:E607-E613. [PMID: 32715746 DOI: 10.1152/ajpendo.00306.2020] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Interleukin (IL)-6 is a pleotropic cytokine with various physiological and pathophysiological functions in different cells and tissues. In cells residing within white adipose tissue, several, and sometimes conflicting, IL-6 actions have been described in the development of obesity-associated derangements of glucose metabolism. Herein, we aim to summarize opposing findings and discuss recent evidence that IL-6 signaling in adipose tissue is regulated in a depot and cell-specific manner.
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Affiliation(s)
- Stephan Wueest
- Division of Pediatric Endocrinology and Diabetology, University Children's Hospital, Zurich, Switzerland
- Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Daniel Konrad
- Division of Pediatric Endocrinology and Diabetology, University Children's Hospital, Zurich, Switzerland
- Children's Research Center, University Children's Hospital, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
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Tsiloulis T, Raajendiran A, Keenan SN, Ooi G, Taylor RA, Burton P, Watt MJ. Impact of human visceral and glutealfemoral adipose tissue transplant on glycemic control in a mouse model of diet-induced obesity. Am J Physiol Endocrinol Metab 2020; 319:E519-E528. [PMID: 32603261 DOI: 10.1152/ajpendo.00373.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Regional distribution of adipose tissue is an important factor in conferring cardiometabolic risk and obesity-related morbidity. We tested the hypothesis that human visceral adipose tissue (VAT) impairs glucose homeostasis, whereas subcutaneous glutealfemoral adipose tissue (GFAT) protects against the development of impaired glucose homeostasis in mice. VAT and GFAT were collected from patients undergoing bariatric surgery and grafted onto the epididymal adipose tissue of weight- and age-matched severe, combined immunodeficient mice. SHAM mice underwent surgery without transplant of tissue. Mice were fed a high-fat diet after xenograft. Energy homeostasis, glucose metabolism, and insulin sensitivity were assessed 6 wk later. Xenograft of human adipose tissues was successful, as determined by histology, immunohistochemical evaluation of collagen deposition and angiogenesis, and maintenance of lipolytic function. Adipose tissue transplant did not affect energy expenditure, food intake, whole body substrate partitioning, or plasma free fatty acid, triglyceride, and insulin levels. Fasting blood glucose was significantly reduced in GFAT and VAT compared with SHAM, whereas glucose tolerance was improved only in mice transplanted with VAT compared with SHAM mice. This improvement was not associated with differences in whole body insulin sensitivity or plasma insulin between groups. Together, these data suggest that VAT improves glycemic control and GFAT does not protect against the development of high-fat diet-induced glucose intolerance. Hence, the intrinsic properties of VAT and GFAT do not necessarily explain the postulated negative and positive effects of these adipose tissue depots on metabolic health.
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Affiliation(s)
- Thomas Tsiloulis
- Department of Physiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
- Monash Biomedicine Discovery Institute; Metabolism, Diabetes and Obesity and Cancer Programs. Monash University, Clayton, Victoria, Australia
| | - Arthe Raajendiran
- Department of Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Stacey N Keenan
- Department of Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Geraldine Ooi
- Centre for Obesity Research and Education, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Renea A Taylor
- Department of Physiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
- Monash Biomedicine Discovery Institute; Metabolism, Diabetes and Obesity and Cancer Programs. Monash University, Clayton, Victoria, Australia
- Cancer Research Division, Peter MacCallum Cancer Centre, Victorian Comprehensive Cancer Centre, Parkville, Australia
| | - Paul Burton
- Centre for Obesity Research and Education, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Matthew J Watt
- Department of Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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Xu Y, Du X, Turner N, Brown AJ, Yang H. Enhanced acyl-CoA:cholesterol acyltransferase activity increases cholesterol levels on the lipid droplet surface and impairs adipocyte function. J Biol Chem 2019; 294:19306-19321. [PMID: 31727739 DOI: 10.1074/jbc.ra119.011160] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/11/2019] [Indexed: 01/21/2023] Open
Abstract
Cholesterol plays essential structural and signaling roles in mammalian cells, but too much cholesterol can cause cytotoxicity. Acyl-CoA:cholesterol acyltransferases 1 and 2 (ACAT1/2) convert cholesterol into its storage form, cholesteryl esters, regulating a key step in cellular cholesterol homeostasis. Adipose tissue can store >50% of whole-body cholesterol. Interestingly, however, almost no ACAT activity is present in adipose tissue, and most adipose cholesterol is stored in its free form. We therefore hypothesized that increased cholesterol esterification may have detrimental effects on adipose tissue function. Here, using several approaches, including protein overexpression, quantitative RT-PCR, immunofluorescence, and various biochemical assays, we found that ACAT1 expression is significantly increased in the adipose tissue of the ob/ob mice. We further demonstrated that ACAT1/2 overexpression partially inhibited the differentiation of 3T3-L1 preadipocytes. In mature adipocytes, increased ACAT activity reduced the size of lipid droplets (LDs) and inhibited lipolysis and insulin signaling. Paradoxically, the amount of free cholesterol increased on the surface of LDs in ACAT1/2-overexpressing adipocytes, accompanied by increased LD localization of caveolin-1. Moreover, cholesterol depletion in adipocytes by treating the cells with cholesterol-deficient media or β-cyclodextrins induced changes in cholesterol distribution that were similar to those caused by ACAT1/2 overexpression. Our results suggest that ACAT1/2 overexpression increases the level of free cholesterol on the LD surface, thereby impeding adipocyte function. These findings provide detailed insights into the role of free cholesterol in LD and adipocyte function and suggest that ACAT inhibitors have potential utility for managing disorders associated with extreme obesity.
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Affiliation(s)
- Yanqing Xu
- School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Nigel Turner
- School of Medical Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, the University of New South Wales, Sydney, New South Wales 2052, Australia
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Page AJ, Hatzinikolas G, Vincent AD, Cavuoto P, Wittert GA. The TRPV1 channel regulates glucose metabolism. Am J Physiol Endocrinol Metab 2019; 317:E667-E676. [PMID: 31408376 DOI: 10.1152/ajpendo.00102.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Endocannabinoids (ECs) mediate effects via cannabinoid receptor types 1 and 2 (CB1 and 2) and transient receptor potential channel-vanilloid subfamily member 1 (TRPV1) channels. In high-fat diet (HFD)-induced obese mice overactivity of the EC system and inhibition of CB1 increase skeletal muscle glucose uptake. We explored the role of TRPV1. Male TRPV1+/+(WT) and TRPV1-/-(KO)-mice were fed (20 wk) a standard laboratory diet (SLD) or HFD. An intraperitoneal glucose tolerance test was performed. RT-PCR was performed to measure mRNA of genes involved in glucose/lipid metabolism and the EC system in soleus (SOL) and extensor digitorum longus (EDL) muscles. Cultured L6 cells were used to measure glucose uptake in skeletal muscle. HFD mice weighed more and had higher insulin levels than SLD mice, with no genotype differences. Basal and peak glucose were higher in HFD mice irrespective of genotype, but glucose cleared faster in HFD WT vs. HFD KO-mice. 2-Arachidonoylglycerol augmented insulin-induced glucose uptake in skeletal L6-cells, an effect blocked by the TRPV1 antagonist SB-366791. In EDL, fatty acid amide hydrolase (FAAH) mRNA was increased in KO vs. WT mice, irrespective of diet. Pyruvate dehydrogenase kinase isozyme 4 (PDK4) and mitochondrial uncoupling protein 3 (UCP3) were elevated and FA desaturase 2 (FADS2) mRNA lower in HFD mice, irrespective of genotype. CB1 and stearoyl-CoA desaturase 1 (SCD1) were lower in HFD WT mice only. In SOL, PDK4, UCP3, hormone-sensitive lipase (LIPE), fatty acid translocase (CD36), and carnitine palmitoyl transferase 2 (CPT2) were elevated and SCD1, FAAH, FADS2, and Troponin 1 (TNNC1) mRNA lower in HFD mice, irrespective of genotype. In conclusion, TRPV1 regulates glucose disposal in HFD mice. We propose that TRPV1 plays a role in coordinating glucose metabolism in EDL under conditions of metabolic stress.
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Affiliation(s)
- Amanda J Page
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - George Hatzinikolas
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Andrew D Vincent
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Paul Cavuoto
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Gary A Wittert
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Freemasons Foundation Centre for Men's Health, University of Adelaide, Adelaide, South Australia, Australia
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9
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Zoso A, Zambon A, Gagliano O, Giulitti S, Prevedello L, Fadini GP, Luni C, Elvassore N. Cross-talk of healthy and impaired human tissues for dissection of disease pathogenesis. Biotechnol Prog 2018; 35:e2766. [PMID: 30548838 DOI: 10.1002/btpr.2766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 11/11/2022]
Abstract
Systemic diseases affect multiple tissues that interact with each other within a network difficult to explore at the body level. However, understanding the interdependences between tissues could be of high relevance for drug target identification, especially at the first stages of disease development. In vitro systems have the advantages of accessibility to measurements and precise controllability of culture conditions, but currently have limitations in mimicking human in vivo systemic tissue response. In this work, we present an in vitro model of cross-talk between an ex vivo culture of adipose tissue from an obese donor and a skeletal muscle in vitro model from a healthy donor. This is relevant to understand type 2 diabetes mellitus pathogenesis, as obesity is one of its main risk factors. The human adipose tissue biopsy was maintained as a three-dimensional culture for 48 h. Its conditioned culture medium was used to stimulate a human skeletal muscle-on-chip, developed by differentiating primary cells of a patient's biopsy under topological cues and molecular self-regulation. This system has been characterized to demonstrate its ability to mimic important features of the normal skeletal muscle response in vivo. We then found that the conditioned medium from a diseased adipose tissue is able to perturb the normal insulin sensitivity of a healthy skeletal muscle, as reported in the early stages of diabetes onset. In perspective, this work represents an important step toward the development of technological platforms that allow to study and dissect the systemic interaction between unhealthy and healthy tissues in vitro. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2766, 2019.
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Affiliation(s)
- Alice Zoso
- Venetian Inst. of Molecular Medicine, Via Orus 2, Padova, 35129, Italy.,Dept. of Industrial Engineering, University of Padova, Via Marzolo 9, Padova, 35131, Italy
| | - Alessandro Zambon
- Venetian Inst. of Molecular Medicine, Via Orus 2, Padova, 35129, Italy.,Dept. of Industrial Engineering, University of Padova, Via Marzolo 9, Padova, 35131, Italy
| | - Onelia Gagliano
- Venetian Inst. of Molecular Medicine, Via Orus 2, Padova, 35129, Italy.,Dept. of Industrial Engineering, University of Padova, Via Marzolo 9, Padova, 35131, Italy
| | - Stefano Giulitti
- Venetian Inst. of Molecular Medicine, Via Orus 2, Padova, 35129, Italy.,Dept. of Industrial Engineering, University of Padova, Via Marzolo 9, Padova, 35131, Italy
| | - Luca Prevedello
- Dept. of Surgery, Oncology and Gastroenterology, University of Padova, Padova, 35124, Italy
| | | | - Camilla Luni
- Shanghai Inst. for Advanced Immunochemical Studies, ShanghaiTech University, 393 Huaxia Road, Shanghai, 201210, China
| | - Nicola Elvassore
- Venetian Inst. of Molecular Medicine, Via Orus 2, Padova, 35129, Italy.,Dept. of Industrial Engineering, University of Padova, Via Marzolo 9, Padova, 35131, Italy.,Shanghai Inst. for Advanced Immunochemical Studies, ShanghaiTech University, 393 Huaxia Road, Shanghai, 201210, China.,Stem Cells & Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, U.K
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10
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Abstract
Obesity is associated with altered gut microbiota composition and impaired gut barrier function. These changes, together with interrelated mesenteric adipose tissue inflammation, result in increased release of pro-inflammatory cytokines, bacteria-derived factors, and lipids into the portal circulation, promoting the development of (hepatic) insulin resistance. Herein, the potential impact of obesity-related changes in gut and visceral adipose tissue biology on the development of insulin resistance and Type 2 diabetes is reviewed.
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Affiliation(s)
- Daniel Konrad
- Department of Pediatric Endocrinology and Diabetology, University Children's Hospital, Zurich, Switzerland; Children's Research Center, University Children's Hospital, Zurich, Switzerland; and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Stephan Wueest
- Department of Pediatric Endocrinology and Diabetology, University Children's Hospital, Zurich, Switzerland; Children's Research Center, University Children's Hospital, Zurich, Switzerland; and
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11
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Lam YY, Ha CWY, Campbell CR, Mitchell AJ, Dinudom A, Oscarsson J, Cook DI, Hunt NH, Caterson ID, Holmes AJ, Storlien LH. Increased gut permeability and microbiota change associate with mesenteric fat inflammation and metabolic dysfunction in diet-induced obese mice. PLoS One 2012; 7:e34233. [PMID: 22457829 PMCID: PMC3311621 DOI: 10.1371/journal.pone.0034233] [Citation(s) in RCA: 435] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/24/2012] [Indexed: 02/06/2023] Open
Abstract
We investigated the relationship between gut health, visceral fat dysfunction and metabolic disorders in diet-induced obesity. C57BL/6J mice were fed control or high saturated fat diet (HFD). Circulating glucose, insulin and inflammatory markers were measured. Proximal colon barrier function was assessed by measuring transepithelial resistance and mRNA expression of tight-junction proteins. Gut microbiota profile was determined by 16S rDNA pyrosequencing. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 mRNA levels were measured in proximal colon, adipose tissue and liver using RT-qPCR. Adipose macrophage infiltration (F4/80+) was assessed using immunohistochemical staining. HFD mice had a higher insulin/glucose ratio (P = 0.020) and serum levels of serum amyloid A3 (131%; P = 0.008) but reduced circulating adiponectin (64%; P = 0.011). In proximal colon of HFD mice compared to mice fed the control diet, transepithelial resistance and mRNA expression of zona occludens 1 were reduced by 38% (P<0.001) and 40% (P = 0.025) respectively and TNF-α mRNA level was 6.6-fold higher (P = 0.037). HFD reduced Lactobacillus (75%; P<0.001) but increased Oscillibacter (279%; P = 0.004) in fecal microbiota. Correlations were found between abundances of Lactobacillus (r = 0.52; P = 0.013) and Oscillibacter (r = −0.55; P = 0.007) with transepithelial resistance of the proximal colon. HFD increased macrophage infiltration (58%; P = 0.020), TNF-α (2.5-fold, P<0.001) and IL-6 mRNA levels (2.5-fold; P = 0.008) in mesenteric fat. Increased macrophage infiltration in epididymal fat was also observed with HFD feeding (71%; P = 0.006) but neither TNF-α nor IL-6 was altered. Perirenal and subcutaneous adipose tissue showed no signs of inflammation in HFD mice. The current results implicate gut dysfunction, and attendant inflammation of contiguous adipose, as salient features of the metabolic dysregulation of diet-induced obesity.
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Affiliation(s)
- Yan Y Lam
- Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, University of Sydney, Sydney, Australia.
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Insulin-stimulated glucose uptake and pathways regulating energy metabolism in skeletal muscle cells: the effects of subcutaneous and visceral fat, and long-chain saturated, n-3 and n-6 polyunsaturated fatty acids. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1811:468-75. [PMID: 21570480 DOI: 10.1016/j.bbalip.2011.04.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 04/05/2011] [Accepted: 04/27/2011] [Indexed: 02/06/2023]
Abstract
AIMS The study aims to determine the effect of long-chain saturated and polyunsaturated (PUFA) fatty acids, specifically palmitic acid (PA; 16:0), docosahexaenoic acid (DHA; 22:6n-3) and linoleic acid (LA; 18:2n-6), and their interactions with factors from adipose tissue, on insulin sensitivity and lipid metabolism in skeletal muscle. METHODS L6 myotubes were cultured with PA, DHA or LA (0.4mmol/l), with or without conditioned media from human subcutaneous (SC) and visceral (IAB) fat. Insulin-stimulated glucose uptake, lipid content, mRNA expression of key genes involved in nutrient utilization and protein expression of inhibitor protein inhibitor kappa B (IκB)-α and mammalian target of rapamycin (mTOR) were measured. RESULTS PA and IAB fat reduced insulin-stimulated glucose uptake and their combined effect was similar to that of PA alone. PA-induced insulin resistance was ameliorated by inhibiting the de novo synthesis of ceramide, IκBα degradation or mTOR activation. The PA effect was also partially reversed by DHA and completely by LA in the presence of SC fat. PA increased diacylglycerol content, which was reduced by LA and to a greater extent when either IAB or SC fat was also present. PA increased SCD1 whereas DHA and LA increased AMPKα2 mRNA. In the presence of SC or IAB fat, the combination of PA with either DHA or LA decreased SCD1 and increased AMPKα2 mRNA. CONCLUSIONS PA-induced insulin resistance in skeletal muscle involves inflammatory (nuclear factor kappa B/mTOR) and nutrient (ceramide) pathways. PUFAs promote pathways, at a transcriptional level, that increase fat oxidation and synergize with factors from SC fat to abrogate PA-induced insulin resistance.
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Belobrajdic DP, Lam YY, Mano M, Wittert GA, Bird AR. Cereal based diets modulate some markers of oxidative stress and inflammation in lean and obese Zucker rats. Nutr Metab (Lond) 2011; 8:27. [PMID: 21535898 PMCID: PMC3108278 DOI: 10.1186/1743-7075-8-27] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 05/03/2011] [Indexed: 01/12/2023] Open
Abstract
Background The potential of cereals with high antioxidant capacity for reducing oxidative stress and inflammation in obesity is unknown. This study investigated the impact of wheat bran, barley or a control diet (α-cellulose) on the development of oxidative stress and inflammation in lean and obese Zucker rats. Methods Seven wk old, lean and obese male Zucker rats (n = 8/group) were fed diets that contained wheat bran, barley or α-cellulose (control). After 3 months on these diets, systolic blood pressure was measured and plasma was analysed for glucose, insulin, lipids, oxygen radical absorbance capacity (ORAC), malondialdehyde, glutathione peroxidase and adipokine concentration (leptin, adiponectin, interleukin (IL)-1β, IL-6, TNFα, plasminogen activator inhibitor (PAI)-1, monocyte chemotactic protein (MCP)-1). Adipokine secretion rates from visceral and subcutaneous adipose tissue explants were also determined. Results Obese rats had higher body weight, systolic blood pressure and fasting blood lipids, glucose, insulin, leptin and IL-1β in comparison to lean rats, and these measures were not reduced by consumption of wheat bran or barley based diets. Serum ORAC tended to be higher in obese rats fed wheat bran and barley in comparison to control (p = 0.06). Obese rats had higher plasma malondialdehyde (p < 0.01) and lower plasma glutathione peroxidase concentration (p < 0.01) but these levels were not affected by diet type. PAI-1 was elevated in the plasma of obese rats, and the wheat bran diet in comparison to the control group reduced PAI-1 to levels seen in the lean rats (p < 0.05). These changes in circulating PAI-1 levels could not be explained by PAI-1 secretion rates from visceral or subcutaneous adipose tissue. Conclusions A 3-month dietary intervention was sufficient for Zucker obese rats to develop oxidative stress and systemic inflammation. Cereal-based diets with moderate and high antioxidant capacity elicited modest improvements in indices of oxidative stress and inflammation.
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Affiliation(s)
- Damien P Belobrajdic
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Food Futures Flagship, Adelaide, 5000, Australia.
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