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Bansal SK, Bansal MB. Pathogenesis of MASLD and MASH - role of insulin resistance and lipotoxicity. Aliment Pharmacol Ther 2024; 59 Suppl 1:S10-S22. [PMID: 38451123 DOI: 10.1111/apt.17930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 12/26/2023] [Accepted: 02/20/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND Insulin resistance and lipotoxicity are extremely interconnected but fundamental in setting the stage for the development of MASLD/MASH. AIM/METHODS A comprehensive literature search was performed and key themes were synthesised to provide insight into the underlying molecular mechanisms of insulin resistance and lipotoxicity in the liver, muscle, pancreas and adipose tissue and how organ cross-talk is fundamental to driving disease pathogenesis. RESULTS Classical thinking postulates that excess FFA load exceeds the storage capacity of adipose tissue, which is predicated upon both genetic and environmental factors. This results in insulin resistance and compensatory hyperinsulinaemia by pancreatic beta cells to overcome target organ insulin resistance. As adipocyte dysfunction worsens, not only are excess FFA delivered to other organs, including skeletal muscle, pancreas and liver but a pro-inflammatory milieu is established with increases in IL-6, TNF-α and changes in adipokine levels (increased leptin and decreased adiponectin). With increased intramuscular lipid accumulation, lipotoxic species decrease insulin signalling, reduce glucose uptake by downregulation of GLUT4 and decrease glycogen synthesis. With this additional reduced capacity, hyperglycaemia is further exacerbated and increased FFA are delivered to the liver. The liver has the largest capacity to oxidise fat and to adapt to these stressors and, therefore, has become the last line of defence for excess lipid storage and utilisation, the capacity of which may be impacted by genetic and environmental factors. However, when the liver can no longer keep up with increasing FFA delivery and DNL, lipotoxic species accumulate with ensuing mitochondrial dysfunction, increased ER stress, oxidant stress and inflammasome activation, all of which drive hepatocyte injury and apoptosis. The resulting wound healing response, marked by stellate cell activation, drives collagen accumulation, progressive fibrosis, and, ultimately, end organ failure and death. This vicious cycle and complex interplay between insulin resistance, hyperinsulinaemia, lipotoxicity and multi-directional cross-talk among different target organs are critical drivers of MASLD/MASH. CONCLUSIONS Targeting tissue-specific insulin resistance and hyperinsulinaemia while decreasing FFA load (lipotoxicity) through dietary and lifestyle changes remain the best upstream interventions.
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Affiliation(s)
- Shalini K Bansal
- Sidney Kimmel College of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Meena B Bansal
- Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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2
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Hwang J, Balakrishnan R, Oh E, Veluthakal R, Thurmond DC. A Novel Role for DOC2B in Ameliorating Palmitate-Induced Glucose Uptake Dysfunction in Skeletal Muscle Cells via a Mechanism Involving β-AR Agonism and Cofilin. Int J Mol Sci 2023; 25:137. [PMID: 38203312 PMCID: PMC10779393 DOI: 10.3390/ijms25010137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Diet-related lipotoxic stress is a significant driver of skeletal muscle insulin resistance (IR) and type 2 diabetes (T2D) onset. β2-adrenergic receptor (β-AR) agonism promotes insulin sensitivity in vivo under lipotoxic stress conditions. Here, we established an in vitro paradigm of lipotoxic stress using palmitate (Palm) in rat skeletal muscle cells to determine if β-AR agonism could cooperate with double C-2-like domain beta (DOC2B) enrichment to promote skeletal muscle insulin sensitivity under Palm-stress conditions. Previously, human T2D skeletal muscles were shown to be deficient for DOC2B, and DOC2B enrichment resisted IR in vivo. Our Palm-stress paradigm induced IR and β-AR resistance, reduced DOC2B protein levels, triggered cytoskeletal cofilin phosphorylation, and reduced GLUT4 translocation to the plasma membrane (PM). By enhancing DOC2B levels in rat skeletal muscle, we showed that the deleterious effects of palmitate exposure upon cofilin, insulin, and β-AR-stimulated GLUT4 trafficking to the PM and glucose uptake were preventable. In conclusion, we revealed a useful in vitro paradigm of Palm-induced stress to test for factors that can prevent/reverse skeletal muscle dysfunctions related to obesity/pre-T2D. Discerning strategies to enrich DOC2B and promote β-AR agonism can resist skeletal muscle IR and halt progression to T2D.
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Affiliation(s)
- Jinhee Hwang
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
- Department of Food and Biotechnology, College of Science and Technology, Korea University, Sejong 30019, Republic of Korea
| | - Rekha Balakrishnan
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
| | - Eunjin Oh
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
| | - Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA; (J.H.); (R.B.); (E.O.); (R.V.)
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Bahn YJ, Yadav H, Piaggi P, Abel BS, Gavrilova O, Springer DA, Papazoglou I, Zerfas PM, Skarulis MC, McPherron AC, Rane SG. CDK4-E2F3 signals enhance oxidative skeletal muscle fiber numbers and function to affect myogenesis and metabolism. J Clin Invest 2023; 133:e162479. [PMID: 37395281 PMCID: PMC10313363 DOI: 10.1172/jci162479] [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: 06/08/2022] [Accepted: 05/19/2023] [Indexed: 07/04/2023] Open
Abstract
Understanding how skeletal muscle fiber proportions are regulated is vital to understanding muscle function. Oxidative and glycolytic skeletal muscle fibers differ in their contractile ability, mitochondrial activity, and metabolic properties. Fiber-type proportions vary in normal physiology and disease states, although the underlying mechanisms are unclear. In human skeletal muscle, we observed that markers of oxidative fibers and mitochondria correlated positively with expression levels of PPARGC1A and CDK4 and negatively with expression levels of CDKN2A, a locus significantly associated with type 2 diabetes. Mice expressing a constitutively active Cdk4 that cannot bind its inhibitor p16INK4a, a product of the CDKN2A locus, were protected from obesity and diabetes. Their muscles exhibited increased oxidative fibers, improved mitochondrial properties, and enhanced glucose uptake. In contrast, loss of Cdk4 or skeletal muscle-specific deletion of Cdk4's target, E2F3, depleted oxidative myofibers, deteriorated mitochondrial function, and reduced exercise capacity, while increasing diabetes susceptibility. E2F3 activated the mitochondrial sensor PPARGC1A in a Cdk4-dependent manner. CDK4, E2F3, and PPARGC1A levels correlated positively with exercise and fitness and negatively with adiposity, insulin resistance, and lipid accumulation in human and rodent muscle. All together, these findings provide mechanistic insight into regulation of skeletal muscle fiber-specification that is of relevance to metabolic and muscular diseases.
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Affiliation(s)
- Young Jae Bahn
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | - Hariom Yadav
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | - Paolo Piaggi
- Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, Arizona
| | - Brent S. Abel
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core Facility, National Institute of Diabetes and Digestive and Kidney Diseases
| | | | - Ioannis Papazoglou
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | | | - Monica C. Skarulis
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | - Alexandra C. McPherron
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | - Sushil G. Rane
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
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4
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Lee MC, Hsu YJ, Sung HC, Wen YT, Wei L, Huang CC. Low Aerobic Capacity Accelerates Lipid Accumulation and Metabolic Abnormalities Caused by High-Fat Diet-Induced Obesity in Postpartum Mice. Nutrients 2022; 14:nu14183746. [PMID: 36145123 PMCID: PMC9502809 DOI: 10.3390/nu14183746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/26/2022] Open
Abstract
Women during pregnancy and postpartum show high rates of obesity and metabolic diseases, especially women with excessive caloric intake. In the past, it was proved that individuals with high intrinsic aerobic exercise capacities showed higher lipid metabolism and lower fat production than those with low intrinsic aerobic exercise capacities. The purpose of this study was to determine whether mice with the low-fitness phenotype (LAEC) were more likely to develop metabolic abnormalities and obesity under dietary induction after delivery, and if mice with a high-fitness phenotype (HAEC) had a protective mechanism. After parturition and weaning, postpartum Institute of Cancer Research (ICR) mice received dietary induction for 12 weeks and were divided into four groups (n = 8 per group): high-exercise capacity postpartum mice with a normal chow diet (HAEC-ND); high-exercise capacity postpartum mice with a high-fat diet (HAEC-HFD); low-exercise capacity postpartum mice with a normal chow diet (LAEC-ND); and low-exercise capacity postpartum mice with a high-fat diet (LAEC-HFD). Obesity caused by a high-fat diet led to decreased exercise performance (p < 0.05). Although there were significant differences in body posture under congenital conditions, the LAEC mice gained more weight and body fat after high-fat-diet intake (p < 0.05). Compared with HAEC-HFD, LAEC-HFD significantly increased blood lipids, such as total cholesterol (TC), triacylglycerol (TG), low-density lipoprotein (LDL) and other parameters (p < 0.05), and the content of TG in the liver, as well as inducing poor glucose tolerance (p < 0.05). In addition, after HFD intake, excessive energy significantly increased glycogen storage (p < 0.05), but the LAEC mice showed significantly lower muscle glycogen storage (p < 0.05). In conclusion, although we observed significant differences in intrinsic exercise capacity, and body posture and metabolic ability were also different, high-fat-diet intake caused weight gain and a risk of metabolic disorders, especially in postpartum low-fitness mice. However, HAEC mice still showed better lipid metabolism and protection mechanisms. Conversely, LAEC mice might accumulate more fat and develop metabolic diseases compared with their normal rodent chow diet (ND) control counterparts.
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Affiliation(s)
- Mon-Chien Lee
- Graduate Institute of Sports Science, National Taiwan Sport University, Taoyuan 333325, Taiwan
| | - Yi-Ju Hsu
- Graduate Institute of Sports Science, National Taiwan Sport University, Taoyuan 333325, Taiwan
| | - Hsin-Ching Sung
- Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan 333323, Taiwan
- Aesthetic Medical Center, Department of Dermatology, Chang Gung Memorial Hospital, Taoyuan 333423, Taiwan
| | - Ya-Ting Wen
- Division of Neurosurgery, Department of Surgery, Wan Fang Hospital, Taipei Medical University, Taipei 116081, Taiwan
| | - Li Wei
- Division of Neurosurgery, Department of Surgery, Wan Fang Hospital, Taipei Medical University, Taipei 116081, Taiwan
- Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei 110301, Taiwan
- Taipei Neuroscience Institute, Taipei Medical University, Taipei 110301, Taiwan
- Correspondence: (L.W.); (C.-C.H.); Tel.: +886-2-27361661 (ext. 6579) (L.W.); +886-3-328-3201 (ext. 2619) (C.-C.H.)
| | - Chi-Chang Huang
- Graduate Institute of Sports Science, National Taiwan Sport University, Taoyuan 333325, Taiwan
- Correspondence: (L.W.); (C.-C.H.); Tel.: +886-2-27361661 (ext. 6579) (L.W.); +886-3-328-3201 (ext. 2619) (C.-C.H.)
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5
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Nomikos T, Methenitis S, Panagiotakos DB. The emerging role of skeletal muscle as a modulator of lipid profile the role of exercise and nutrition. Lipids Health Dis 2022; 21:81. [PMID: 36042487 PMCID: PMC9425975 DOI: 10.1186/s12944-022-01692-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 08/16/2022] [Indexed: 11/10/2022] Open
Abstract
The present article aims to discuss the hypothesis that skeletal muscle per se but mostly its muscle fiber composition could be significant determinants of lipid metabolism and that certain exercise modalities may improve metabolic dyslipidemia by favorably affecting skeletal muscle mass, fiber composition and functionality. It discusses the mediating role of nutrition, highlights the lack of knowledge on mechanistic aspects of this relationship and proposes possible experimental directions in this field.
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Affiliation(s)
- Tzortzis Nomikos
- Department of Nutrition and Dietetics, School of Health Sciences & Education, Harokopio University, Athens, Greece.
| | - Spyridon Methenitis
- Sports Performance Laboratory, School of Physical Education and Sports. Science, National and Kapodistrian University of Athens, Athens, Greece.,Theseus, Physical Medicine and Rehabilitation Center, Athens, Greece
| | - Demosthenes B Panagiotakos
- Department of Nutrition and Dietetics, School of Health Sciences & Education, Harokopio University, Athens, Greece
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6
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Palmer BF, Clegg DJ. Metabolic Flexibility and Its Impact on Health Outcomes. Mayo Clin Proc 2022; 97:761-776. [PMID: 35287953 DOI: 10.1016/j.mayocp.2022.01.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/04/2022] [Accepted: 01/12/2022] [Indexed: 02/06/2023]
Abstract
A metabolically flexible state exists when there is a rapid switch between glucose and fatty acids during the transition between the fed and fasting state. This flexibility in fuel choice serves to prevent hyperglycemia following a meal and simultaneously ensures an adequate amount of blood glucose is available for delivery to the brain and exclusively glycolytic tissues during fasting. The modern era is characterized by chronic overnutrition in which a mixture of fuels is delivered to the mitochondria in an unabated manner thereby uncoupling the feast and famine situation. The continuous influx of fuel leads to accumulation of reducing equivalents in the mitochondria and an increase in the mitochondrial membrane potential. These changes create a microenvironment fostering the generation of reactive oxygen species and other metabolites leading to deleterious protein modification, cell injury, and ultimately clinical disease. Insulin resistance may also play a primary role in this deleterious effect. The imbalance between mitochondrial energy delivery and use is made worse with a sedentary lifestyle. Maneuvers that restore energy balance across the mitochondria activate pathways that remove or repair damaged molecules and restore the plasticity characteristic of normal energy metabolism. Readily available strategies to maintain energy balance across the mitochondria include exercise, various forms of caloric restriction, administration of sodium-glucose cotransporter-2 inhibitors, cold exposure, and hypobaric hypoxia.
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Affiliation(s)
- Biff F Palmer
- Department of Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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7
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Mthembu SXH, Mazibuko-Mbeje SE, Ziqubu K, Nyawo TA, Obonye N, Nyambuya TM, Nkambule BB, Silvestri S, Tiano L, Muller CJF, Dludla PV. Impact of physical exercise and caloric restriction in patients with type 2 diabetes: Skeletal muscle insulin resistance and mitochondrial dysfunction as ideal therapeutic targets. Life Sci 2022; 297:120467. [PMID: 35271881 DOI: 10.1016/j.lfs.2022.120467] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 01/01/2023]
Abstract
Skeletal muscle insulin resistance and mitochondrial dysfunction are some of the major pathological defects implicated in the development of type 2 diabetes (T2D). Therefore, it has become necessary to understand how common interventions such as physical exercise and caloric restriction affect metabolic function, including physiological processes that implicate skeletal muscle dysfunction within a state of T2D. This review critically discusses evidence on the impact of physical exercise and caloric restriction on markers of insulin resistance and mitochondrial dysfunction within the skeletal muscle of patients with T2D or related metabolic complications. Importantly, relevant information from clinical studies was acquired through a systematic approach targeting major electronic databases and search engines such as PubMed, Google Scholar, and Cochrane library. The reported evidence suggests that interventions like physical exercise and caloric restriction, within a duration of approximately 2 to 4 months, can improve insulin sensitivity, in part by targeting the phosphoinositide 3-kinases/protein kinase B pathway in patients with T2D. Furthermore, both physical exercise and caloric restriction can effectively modulate markers related to improved mitochondrial function and dynamics. This was consistent with an improved modulation of mitochondrial oxidative capacity and reduced production of reactive oxygen species in patients with T2D or related metabolic complications. However, such conclusions are based on limited evidence, additional clinical trials are required to better understand these interventions on pathological mechanisms of T2D and related abnormalities.
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Affiliation(s)
- Sinenhlanhla X H Mthembu
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg 7505, South Africa; Department of Biochemistry, North-West University, Mafikeng Campus, Mmabatho 2735, South Africa
| | | | - Khanyisani Ziqubu
- Department of Biochemistry, North-West University, Mafikeng Campus, Mmabatho 2735, South Africa
| | - Thembeka A Nyawo
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg 7505, South Africa; Centre for Cardiometabolic Research Africa (CARMA), Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa
| | - Nnini Obonye
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg 7505, South Africa; Centre for Cardiometabolic Research Africa (CARMA), Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa
| | - Tawanda M Nyambuya
- Department of Health Sciences, Faculty of Health and Applied Sciences, Namibia University of Science and Technology, Windhoek 9000, Namibia
| | - Bongani B Nkambule
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu Natal, Durban 4000, South Africa
| | - Sonia Silvestri
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
| | - Luca Tiano
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
| | - Christo J F Muller
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg 7505, South Africa; Centre for Cardiometabolic Research Africa (CARMA), Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa; Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3880, South Africa
| | - Phiwayinkosi V Dludla
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg 7505, South Africa.
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Gilloteaux J, Nicaise C, Sprimont L, Bissler J, Finkelstein JA, Payne WR. Leptin receptor defect with diabetes causes skeletal muscle atrophy in female obese Zucker rats where peculiar depots networked with mitochondrial damages. Ultrastruct Pathol 2021; 45:346-375. [PMID: 34743665 DOI: 10.1080/01913123.2021.1983099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Tibialis anterior muscles of 45-week-old female obese Zucker rats with defective leptin receptor and non-insulin dependent diabetes mellitus (NIDDM) showed a significative atrophy compared to lean muscles, based on histochemical-stained section's measurements in the sequence: oxidative slow twitch (SO, type I) < oxidative fast twitch (FOG, type IIa) < fast glycolytic (FG, type IIb). Both oxidative fiber's outskirts resembled 'ragged' fibers and, in these zones, ultrastructure revealed small clusters of endoplasm-like reticulum filled with unidentified electron contrasted compounds, contiguous and continuous with adjacent mitochondria envelope. The linings appeared crenated stabbed by circular patterns resembling those found of ceramides. The same fibers contained scattered degraded mitochondria that tethered electron contrasted droplets favoring larger depots while mitoptosis were widespread in FG fibers. Based on other interdisciplinary investigations on the lipid depots of diabetes 2 muscles made us to propose these accumulated contrasted contents to be made of peculiar lipids, including acyl-ceramides, as those were only found while diabetes 2 progresses in aging obese rats. These could interfere in NIDDM with mitochondrial oxidative energetic demands and muscle functions.
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Affiliation(s)
- Jacques Gilloteaux
- Department of Anatomical Sciences, St George's University School of Medicine, K B Taylor Global Scholar's Program at the University of Northumbria, School of Health and Life Sciences, Newcastle upon Tyne, UK.,Unité de Recherches de Physiologie Moleculaire (URPHyM) - Narilis, Département de Médecine, Université de Namur, Namur, Belgium.,Department of Anatomy, Northeast Ohio Medical University (Neomed), Rootstown, OH, USA
| | - Charles Nicaise
- Unité de Recherches de Physiologie Moleculaire (URPHyM) - Narilis, Département de Médecine, Université de Namur, Namur, Belgium
| | - Lindsay Sprimont
- Unité de Recherches de Physiologie Moleculaire (URPHyM) - Narilis, Département de Médecine, Université de Namur, Namur, Belgium
| | - John Bissler
- Department of Anatomy, Northeast Ohio Medical University (Neomed), Rootstown, OH, USA.,Division of Nephrology at St. Jude Children's Research Hospital and Le Bonheur Children's Hospital, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Judith A Finkelstein
- Department of Anatomy, Northeast Ohio Medical University (Neomed), Rootstown, OH, USA
| | - Warren R Payne
- Institute for Sport and Health, Footscray Park Campus, Victoria University, Melbourne, VIC, Australia
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Vandanmagsar B, Yu Y, Simmler C, Dang TN, Kuhn P, Poulev A, Ribnicky DM, Pauli GF, Floyd ZE. Bioactive compounds from Artemisia dracunculus L. activate AMPK signaling in skeletal muscle. Biomed Pharmacother 2021; 143:112188. [PMID: 34563947 PMCID: PMC8516709 DOI: 10.1016/j.biopha.2021.112188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 11/30/2022] Open
Abstract
An extract from Artemisia dracunculus L. (termed PMI-5011) improves glucose homeostasis by enhancing insulin action and reducing ectopic lipid accumulation, while increasing fat oxidation in skeletal muscle tissue in obese insulin resistant male mice. A chalcone, DMC-2, in PMI-5011 is the major bioactive that enhances insulin signaling and activation of AKT. However, the mechanism by which PMI-5011 improves lipid metabolism is unknown. AMPK is the cellular energy and metabolic sensor and a key regulator of lipid metabolism in muscle. This study examined PMI-5011 activation of AMPK signaling using murine C2C12 muscle cell culture and skeletal muscle tissue. Findings show that PMI-5011 increases Thr172-phosphorylation of AMPK in muscle cells and skeletal muscle tissue, while hepatic AMPK activation by PMI-5011 was not observed. Increased AMPK activity by PMI-5011 affects downstream signaling of AMPK, resulting in inhibition of ACC and increased SIRT1 protein levels. Selective deletion of DMC-2 from PMI-5011 demonstrates that compounds other than DMC-2 in a "DMC-2 knock out extract" (KOE) are responsible for AMPK activation and its downstream effects. Compared to 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) and metformin, the phytochemical mixture characterizing the KOE appears to more efficiently activate AMPK in muscle cells. KOE-mediated AMPK activation was LKB-1 independent, suggesting KOE does not activate AMPK via LKB-1 stimulation. Through AMPK activation, compounds in PMI-5011 may regulate lipid metabolism in skeletal muscle. Thus, the AMPK-activating potential of the KOE adds therapeutic value to PMI-5011 and its constituents in treating insulin resistance or type 2 diabetes.
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Affiliation(s)
- B Vandanmagsar
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
| | - Y Yu
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
| | - C Simmler
- Center for Natural Product Technologies, Pharmacognosy Institute and Department of Pharmaceutical Sciences, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL 60612, USA
| | - T N Dang
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
| | - P Kuhn
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| | - A Poulev
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| | - D M Ribnicky
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| | - G F Pauli
- Center for Natural Product Technologies, Pharmacognosy Institute and Department of Pharmaceutical Sciences, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL 60612, USA
| | - Z E Floyd
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
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10
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Schmidt CA, Fisher-Wellman KH, Neufer PD. From OCR and ECAR to energy: Perspectives on the design and interpretation of bioenergetics studies. J Biol Chem 2021; 297:101140. [PMID: 34461088 PMCID: PMC8479256 DOI: 10.1016/j.jbc.2021.101140] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Biological energy transduction underlies all physiological phenomena in cells. The metabolic systems that support energy transduction have been of great interest due to their association with numerous pathologies including diabetes, cancer, rare genetic diseases, and aberrant cell death. Commercially available bioenergetics technologies (e.g., extracellular flux analysis, high-resolution respirometry, fluorescent dye kits, etc.) have made practical assessment of metabolic parameters widely accessible. This has facilitated an explosion in the number of studies exploring, in particular, the biological implications of oxygen consumption rate (OCR) and substrate level phosphorylation via glycolysis (i.e., via extracellular acidification rate (ECAR)). Though these technologies have demonstrated substantial utility and broad applicability to cell biology research, they are also susceptible to historical assumptions, experimental limitations, and other caveats that have led to premature and/or erroneous interpretations. This review enumerates various important considerations for designing and interpreting cellular and mitochondrial bioenergetics experiments, some common challenges and pitfalls in data interpretation, and some potential "next steps" to be taken that can address these highlighted challenges.
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Affiliation(s)
- Cameron A Schmidt
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Kelsey H Fisher-Wellman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA; Departments of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
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11
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Experimental models of lipid overload and their relevance in understanding skeletal muscle insulin resistance and pathological changes in mitochondrial oxidative capacity. Biochimie 2021; 196:182-193. [PMID: 34563603 DOI: 10.1016/j.biochi.2021.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/30/2021] [Accepted: 09/20/2021] [Indexed: 02/08/2023]
Abstract
It remains essential to decipher some of the pathological mechanisms that link obesity with deteriorating human health. Insulin resistance, due to enhanced free fatty acid substrate delivery, results in disrupted glucose homeostasis and altered mitochondrial oxidative capacity, which is a characteristic feature of an obese state. In fact, as a major site for regulating glucose homeostasis and energy production in response to insulin, the skeletal muscle has become an interesting target tissue to understand the impact of lipid overload on the development of insulin resistance and impaired mitochondrial respiratory function. In addition to systematically retrieving the discussed data, the current review brings an essential perspective in understanding the relevance of experimental models of lipid overload such as high fat diets in understanding the pathological link between insulin resistance and pathological changes in mitochondrial oxidative capacity. Importantly, inclusion of evidence from transgenic model highlights some of the unique molecular targets that are implicated in the development of insulin resistance and inefficient mitochondrial respiration processes within an obese state. Importantly, saturation with lipid products such as ceramides and diacylglycerols, especially within the skeletal muscle, appears to be instrumental in paving the path leading to worsening of metabolic complications. These metabolic consequences mostly interfere with the efficiency of the mitochondrial electron transport chain, leading to overproduction of toxic reactive oxygen species. Therefore, therapeutic agents that reverse the effects of lipid overload by improving insulin sensitivity and mitochondrial oxidative capacity are crucial for the management or even treatment of metabolic diseases.
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12
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Park M, Kim KH, Jaiswal V, Choi J, Chun JL, Seo KM, Lee MJ, Lee HJ. Effect of black ginseng and silkworm supplementation on obesity, the transcriptome, and the gut microbiome of diet-induced overweight dogs. Sci Rep 2021; 11:16334. [PMID: 34381138 PMCID: PMC8358025 DOI: 10.1038/s41598-021-95789-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/23/2021] [Indexed: 01/04/2023] Open
Abstract
Like humans, weight control in overweight dogs is associated with a longer life expectancy and a healthier life. Dietary supplements are one of the best strategies for controlling obesity and obesity-associated diseases. This study was conducted to assess the potential of black ginseng (BG) and silkworm (SW) as supplements for weight control in diet-induced overweight beagle dogs. To investigate the changes that occur in dogs administered the supplements, different obesity-related parameters, such as body condition score (BCS), blood fatty acid profile, transcriptome, and microbiome, were assessed in high energy diet (HD) and HD with BG + SW supplementation (HDT) groups of test animals. After 12 weeks of BG + SW supplementation, total cholesterol and triglyceride levels were reduced in the HDT group. In the transcriptome analysis, nine genes (NUGGC, EFR3B, RTP4, ACAN, HOXC4, IL17RB, SOX13, SLC18A2, and SOX4) that are known to be associated with obesity were found to be differentially expressed between the ND (normal diet) and HD groups as well as the HD and HDT groups. Significant changes in some taxa were observed between the HD and ND groups. These data suggest that the BG + SW supplement could be developed as dietary interventions against diet-induced obesity, and obesity-related differential genes could be important candidates in the mechanism of the anti-obesity effects of the BG + SW supplement.
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Affiliation(s)
- Miey Park
- Department of Food and Nutrition, College of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, 13120, Gyeonggi-do, Korea
| | - Ki Hyun Kim
- Animal Welfare Research Team, National Institute of Animal Science, National Institute of Animal Science, Rural Development Administration, Wanju, 55365, Korea
| | - Varun Jaiswal
- Department of Food and Nutrition, College of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, 13120, Gyeonggi-do, Korea
| | - Jihee Choi
- Department of Food and Nutrition, College of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, 13120, Gyeonggi-do, Korea
| | - Ju Lan Chun
- Animal Welfare Research Team, National Institute of Animal Science, National Institute of Animal Science, Rural Development Administration, Wanju, 55365, Korea
| | - Kang Min Seo
- Animal Welfare Research Team, National Institute of Animal Science, National Institute of Animal Science, Rural Development Administration, Wanju, 55365, Korea
| | - Mi-Jin Lee
- Clinical Nutritional Medicine, Veterinary Medical Teaching Hospital, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Hae-Jeung Lee
- Department of Food and Nutrition, College of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, 13120, Gyeonggi-do, Korea.
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13
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Mechanism of insulin resistance in obesity: a role of ATP. Front Med 2021; 15:372-382. [PMID: 34047935 DOI: 10.1007/s11684-021-0862-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 04/25/2021] [Indexed: 12/12/2022]
Abstract
Obesity increases the risk of type 2 diabetes through the induction of insulin resistance. The mechanism of insulin resistance has been extensively investigated for more than 60 years, but the essential pathogenic signal remains missing. Existing hypotheses include inflammation, mitochondrial dysfunction, hyperinsulinemia, hyperglucagonemia, glucotoxicity, and lipotoxicity. Drug discoveries based on these hypotheses are unsuccessful in the development of new medicines. In this review, multidisciplinary literature is integrated to evaluate ATP as a primary signal for insulin resistance. The ATP production is elevated in insulin-sensitive cells under obese conditions independent of energy demand, which we have named "mitochondrial overheating." Overheating occurs because of substrate oversupply to mitochondria, leading to extra ATP production. The ATP overproduction contributes to the systemic insulin resistance through several mechanisms, such as inhibition of AMPK, induction of mTOR, hyperinsulinemia, hyperglucagonemia, and mitochondrial dysfunction. Insulin resistance represents a feedback regulation of energy oversupply in cells to control mitochondrial overloading by substrates. Insulin resistance cuts down the substrate uptake to attenuate mitochondrial overloading. The downregulation of the mitochondrial overloading by medicines, bypass surgeries, calorie restriction, and physical exercise leads to insulin sensitization in patients. Therefore, ATP may represent the primary signal of insulin resistance in the cellular protective response to the substrate oversupply. The prevention of ATP overproduction represents a key strategy for insulin sensitization.
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14
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Smith CD, Lin CT, McMillin SL, Weyrauch LA, Schmidt CA, Smith CA, Kurland IJ, Witczak CA, Neufer PD. Genetically increasing flux through β-oxidation in skeletal muscle increases mitochondrial reductive stress and glucose intolerance. Am J Physiol Endocrinol Metab 2021; 320:E938-E950. [PMID: 33813880 PMCID: PMC8238127 DOI: 10.1152/ajpendo.00010.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Elevated mitochondrial hydrogen peroxide (H2O2) emission and an oxidative shift in cytosolic redox environment have been linked to high-fat-diet-induced insulin resistance in skeletal muscle. To test specifically whether increased flux through mitochondrial fatty acid oxidation, in the absence of elevated energy demand, directly alters mitochondrial function and redox state in muscle, two genetic models characterized by increased muscle β-oxidation flux were studied. In mice overexpressing peroxisome proliferator-activated receptor-α in muscle (MCK-PPARα), lipid-supported mitochondrial respiration, membrane potential (ΔΨm), and H2O2 production rate (JH2O2) were increased, which coincided with a more oxidized cytosolic redox environment, reduced muscle glucose uptake, and whole body glucose intolerance despite an increased rate of energy expenditure. Similar results were observed in lipin-1-deficient, fatty-liver dystrophic mice, another model characterized by increased β-oxidation flux and glucose intolerance. Crossing MCAT (mitochondria-targeted catalase) with MCK-PPARα mice normalized JH2O2 production, redox environment, and glucose tolerance, but surprisingly, both basal and absolute insulin-stimulated rates of glucose uptake in muscle remained depressed. Also surprising, when placed on a high-fat diet, MCK-PPARα mice were characterized by much lower whole body, fat, and lean mass as well as improved glucose tolerance relative to wild-type mice, providing additional evidence that overexpression of PPARα in muscle imposes more extensive metabolic stress than experienced by wild-type mice on a high-fat diet. Overall, the findings suggest that driving an increase in skeletal muscle fatty acid oxidation in the absence of metabolic demand imposes mitochondrial reductive stress and elicits multiple counterbalance metabolic responses in an attempt to restore bioenergetic homeostasis.NEW & NOTEWORTHY Prior work has suggested that mitochondrial dysfunction is an underlying cause of insulin resistance in muscle because it limits fatty acid oxidation and therefore leads to the accumulation of cytotoxic lipid intermediates. The implication has been that therapeutic strategies to accelerate β-oxidation will be protective. The current study provides evidence that genetically increasing flux through β-oxidation in muscle imposes reductive stress that is not beneficial but rather detrimental to metabolic regulation.
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Affiliation(s)
- Cody D Smith
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Chien-Te Lin
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Shawna L McMillin
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Biochemistry & Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Luke A Weyrauch
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Biochemistry & Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Cameron A Schmidt
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Cheryl A Smith
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Irwin J Kurland
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York
| | - Carol A Witczak
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Biochemistry & Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Kinesiology, East Carolina University, Greenville, North Carolina
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Biochemistry & Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
- Department of Kinesiology, East Carolina University, Greenville, North Carolina
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15
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Sun H, Sherrier M, Li H. Skeletal Muscle and Bone - Emerging Targets of Fibroblast Growth Factor-21. Front Physiol 2021; 12:625287. [PMID: 33762965 PMCID: PMC7982600 DOI: 10.3389/fphys.2021.625287] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/16/2021] [Indexed: 12/13/2022] Open
Abstract
Fibroblast growth factor 21 (FGF21) is an atypical member of the FGF family, which functions as a powerful endocrine and paracrine regulator of glucose and lipid metabolism. In addition to liver and adipose tissue, recent studies have shown that FGF21 can also be produced in skeletal muscle. As the most abundant tissue in the human body, skeletal muscle has become increasingly recognized as a major site of metabolic activity and an important modulator of systemic metabolic homeostasis. The function and mechanism of action of muscle-derived FGF21 have recently gained attention due to the findings of considerably increased expression and secretion of FGF21 from skeletal muscle under certain pathological conditions. Recent reports regarding the ectopic expression of FGF21 from skeletal muscle and its potential effects on the musculoskeletal system unfolds a new chapter in the story of FGF21. In this review, we summarize the current knowledge base of muscle-derived FGF21 and the possible functions of FGF21 on homeostasis of the musculoskeletal system with a focus on skeletal muscle and bone.
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Affiliation(s)
- Hui Sun
- Musculoskeletal Growth & Regeneration Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Matthew Sherrier
- Musculoskeletal Growth & Regeneration Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Hongshuai Li
- Musculoskeletal Growth & Regeneration Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States
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16
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Mahizir D, Briffa JF, Wood JL, Anevska K, Hill-Yardin EL, Jefferies AJ, Gravina S, Mazzarino G, Franks AE, Moritz KM, Wadley GD, Wlodek ME. Exercise improves metabolic function and alters the microbiome in rats with gestational diabetes. FASEB J 2019; 34:1728-1744. [PMID: 31914625 DOI: 10.1096/fj.201901424r] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/08/2019] [Accepted: 10/30/2019] [Indexed: 12/16/2022]
Abstract
Gestational diabetes mellitus (GDM) is a common pregnancy complication, particularly prevalent in obese women. Importantly, exercise has beneficial impacts on maternal glucose control and may prevent GDM in "at-risk" women. We aimed to determine whether a high-fat diet (HFD) exacerbates metabolic dysfunction and alters gut microbiome in GDM and whether endurance exercise prevents these changes. Uteroplacental insufficiency was induced by bilateral uterine vessel ligation (Restricted) or sham (Control) surgery on E18 in Wistar-Kyoto rats. Female offspring were fed a Chow or HFD (23% fat) from weaning (5 weeks) and at 16 weeks randomly allocated to remain Sedentary or to an exercise protocol of either Exercise prior to and during pregnancy (Exercise); or Exercise during pregnancy only (PregEx). Females were mated (20 weeks) and underwent indirect calorimetry (embryonic day 16; E16), glucose tolerance testing (E18), followed by 24-hr feces collection at E19 (n = 8-10/group). HFD consumption in female rats with GDM exacerbated the adverse metabolic adaptations to pregnancy and altered gut microbial populations. Specifically, the Firmicutes-to-Bacteroidetes ratio was increased, due to an underlying change in abundance of the orders Clostridiales and Bacteroidales. Maternal Exercise, but not PregEx, prevented the development of metabolic dysfunction, increased pancreatic β-cell mass, and prevented the alteration of the gut microbiome in GDM females. Our findings suggest that maternal exercise and diet influence metabolic and microbiome dysfunction in females with GDM, which may impact long-term maternal and offspring health.
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Affiliation(s)
- Dayana Mahizir
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Jessica F Briffa
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Jennifer L Wood
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, Australia.,Centre for Future Landscapes, La Trobe University, Bundoora, VIC, Australia
| | - Kristina Anevska
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, Australia
| | - Elisa L Hill-Yardin
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia.,School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
| | - Andrew J Jefferies
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Sogand Gravina
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Gisella Mazzarino
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD, Australia
| | - Ashley E Franks
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, Australia.,Centre for Future Landscapes, La Trobe University, Bundoora, VIC, Australia
| | - Karen M Moritz
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Glenn D Wadley
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD, Australia
| | - Mary E Wlodek
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
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17
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Nielsen MH, Sabaratnam R, Pedersen AJT, Højlund K, Handberg A. Acute Exercise Increases Plasma Levels of Muscle-Derived Microvesicles Carrying Fatty Acid Transport Proteins. J Clin Endocrinol Metab 2019; 104:4804-4814. [PMID: 30933285 DOI: 10.1210/jc.2018-02547] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 03/26/2019] [Indexed: 02/03/2023]
Abstract
CONTEXT Microvesicles (MVs) are a class of membrane particles shed by any cell in the body in physiological and pathological conditions. They are considered to be key players in intercellular communication, and with a molecular content reflecting the composition of the cell of origin, they have recently emerged as a promising source of biomarkers in a number of diseases. OBJECTIVE The effects of acute exercise on the plasma concentration of skeletal muscle-derived MVs (SkMVs) carrying metabolically important membrane proteins were examined. PARTICIPANTS Thirteen men with obesity and type 2 diabetes mellitus (T2DM) and 14 healthy male controls with obesity exercised on a cycle ergometer for 60 minutes. INTERVENTIONS Muscle biopsies and blood samples-obtained before exercise, immediately after exercise, and 3 hours into recovery-were collected for the analysis of long-chain fatty acid (LCFA) transport proteins CD36 (a scavenger receptor class B protein) and fatty acid transport protein 4 (FATP4) mRNA content in muscle and for flow cytometric studies on circulating SkMVs carrying either LCFA transport protein. RESULTS Besides establishing a flow cytometric approach for the detection of circulating SkMVs and subpopulations carrying either CD36 or FATP4 and thereby adding proof to their existence, we demonstrated an overall exercise-induced change of SkMVs carrying these LCFA transport proteins. A positive correlation between exercise-induced changes in skeletal muscle CD36 mRNA expression and concentrations of SkMVs carrying CD36 was found in T2DM only. CONCLUSIONS This approach could add important real-time information about the abundance of LCFA transport proteins present on activated muscle cells in subjects with impaired glucose metabolism.
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Affiliation(s)
| | - Rugivan Sabaratnam
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Andreas James Thestrup Pedersen
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Kurt Højlund
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Aase Handberg
- Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Faculty of Medicine, Aalborg University, Aalborg, Denmark
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18
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Savage DB, Watson L, Carr K, Adams C, Brage S, Chatterjee KK, Hodson L, Boesch C, Kemp GJ, Sleigh A. Accumulation of saturated intramyocellular lipid is associated with insulin resistance. J Lipid Res 2019; 60:1323-1332. [PMID: 31048405 PMCID: PMC6602127 DOI: 10.1194/jlr.m091942] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/11/2019] [Indexed: 12/17/2022] Open
Abstract
Intramyocellular lipid (IMCL) accumulation has been linked to both insulin-resistant and insulin-sensitive (athletes) states. Biochemical analysis of intramuscular triglyceride composition is confounded by extramyocellular triglycerides in biopsy samples, and hence the specific composition of IMCLs is unknown in these states. 1H magnetic resonance spectroscopy (MRS) can be used to overcome this problem. Thus, we used a recently validated 1H MRS method to compare the compositional saturation index (CH2:CH3) and concentration independent of the composition (CH3) of IMCLs in the soleus and tibialis anterior muscles of 16 female insulin-resistant lipodystrophic subjects with that of age- and gender-matched athletes (n = 14) and healthy controls (n = 41). The IMCL CH2:CH3 ratio was significantly higher in both muscles of the lipodystrophic subjects compared with controls but was similar in athletes and controls. IMCL CH2:CH3 was dependent on the IMCL concentration in the controls and, after adjusting the compositional index for quantity (CH2:CH3adj), could distinguish lipodystrophics from athletes. This CH2:CH3adj marker had a stronger relationship with insulin resistance than IMCL concentration alone and was inversely related to VO2max. The association of insulin resistance with the accumulation of saturated IMCLs is consistent with a potential pathogenic role for saturated fat and the reported benefits of exercise and diet in insulin-resistant states.
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Affiliation(s)
- David B Savage
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Laura Watson
- National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Katie Carr
- National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Claire Adams
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Soren Brage
- MRC Epidemiology Unit University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Krishna K Chatterjee
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom.,National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Chris Boesch
- Department of Clinical Research and Radiology AMSM, University Bern, Bern, Switzerland
| | - Graham J Kemp
- Department of Musculoskeletal Biology University of Liverpool and MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Liverpool, United Kingdom
| | - Alison Sleigh
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom .,National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom.,Wolfson Brain Imaging Centre University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
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19
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Jana BA, Chintamaneni PK, Krishnamurthy PT, Wadhwani A, Mohankumar SK. Cytosolic lipid excess-induced mitochondrial dysfunction is the cause or effect of high fat diet-induced skeletal muscle insulin resistance: a molecular insight. Mol Biol Rep 2018; 46:957-963. [DOI: 10.1007/s11033-018-4551-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 11/30/2018] [Indexed: 12/30/2022]
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20
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Chang W, Hatch GM, Wang Y, Yu F, Wang M. The relationship between phospholipids and insulin resistance: From clinical to experimental studies. J Cell Mol Med 2018; 23:702-710. [PMID: 30402908 PMCID: PMC6349352 DOI: 10.1111/jcmm.13984] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 10/02/2018] [Indexed: 01/21/2023] Open
Abstract
Insulin resistance induced by high‐fat diet and impropriate life style is a major contributor to the pathogenesis of metabolic disease. However, the underlying molecular mechanisms remain unclear. Recent studies in metabolic dysfunction have extended this beyond simply elevated cholesterol and triglycerides levels and have identified a key role for lipid metabolism. For example, altered phospholipid metabolism has now become central in the pathogenesis of metabolic disease. In this review, we discuss the association between insulin sensitivity and phospholipid metabolism and highlight the most significant discoveries generated over the last several decades. Finally, we summarize the current knowledge surrounding the molecular mechanisms related to phospholipids and insulin resistance and provide new insight for future research into their relationship.
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Affiliation(s)
- Wenguang Chang
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Grant M Hatch
- Departments of Pharmacology and Therapeutics, Biochemistry and Medical Genetics, Center for Research and Treatment of Atherosclerosis, DREAM Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada
| | - Yu Wang
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Fei Yu
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Man Wang
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
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21
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Of mice and men: The physiological role of adipose triglyceride lipase (ATGL). Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:880-899. [PMID: 30367950 PMCID: PMC6439276 DOI: 10.1016/j.bbalip.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) has been discovered 14 years ago and revised our view on intracellular triglyceride (TG) mobilization – a process termed lipolysis. ATGL initiates the hydrolysis of TGs to release fatty acids (FAs) that are crucial energy substrates, precursors for the synthesis of membrane lipids, and ligands of nuclear receptors. Thus, ATGL is a key enzyme in whole-body energy homeostasis. In this review, we give an update on how ATGL is regulated on the transcriptional and post-transcriptional level and how this affects the enzymes' activity in the context of neutral lipid catabolism. In depth, we highlight and discuss the numerous physiological functions of ATGL in lipid and energy metabolism. Over more than a decade, different genetic mouse models lacking or overexpressing ATGL in a cell- or tissue-specific manner have been generated and characterized. Moreover, pharmacological studies became available due to the development of a specific murine ATGL inhibitor (Atglistatin®). The identification of patients with mutations in the human gene encoding ATGL and their disease spectrum has underpinned the importance of ATGL in humans. Together, mouse models and human data have advanced our understanding of the physiological role of ATGL in lipid and energy metabolism in adipose and non-adipose tissues, and of the pathophysiological consequences of ATGL dysfunction in mice and men. Summary of mouse models with genetic or pharmacological manipulation of ATGL. Summary of patients with mutations in the human gene encoding ATGL. In depth discussion of the role of ATGL in numerous physiological processes in mice and men.
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22
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Zhao L, Zou T, Gomez NA, Wang B, Zhu MJ, Du M. Raspberry alleviates obesity-induced inflammation and insulin resistance in skeletal muscle through activation of AMP-activated protein kinase (AMPK) α1. Nutr Diabetes 2018; 8:39. [PMID: 29961765 PMCID: PMC6026595 DOI: 10.1038/s41387-018-0049-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/23/2018] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE Through dynamic means, etiological factors, including chronic inflammation and insulin resistance have the potential to perpetuate metabolic incidences such as type 2 diabetes and obesity. Abatement of such syndromes can be achieved by complex mechanisms initiated through bioactive compounds such as polyphenols derived from fruits. Using a whole-fruit approach, the effects of dietary red raspberry, which is rich in polyphenols, on inflammatory responses and insulin resistance in the skeletal muscles of Mus musculus were studied along with the potential role of AMP-activated protein kinase (AMPK) to act as a key mediator. SUBJECTS Wild-type (WT) mice and mice deficient in the catalytic subunit (α1) of AMPK (AMPKα1-/-) were fed with a high-fat diet (HFD) or HFD supplemented with raspberry (5% dry weight) for 10 weeks. Factors involved in inflammatory responses, insulin signaling transduction, and mitochondrial biogenesis were evaluated. RESULTS Dietary raspberry reduced ectopic lipid storage, alleviated inflammation responses, improved whole-body insulin sensitivity, and promoted mitochondrial biogenesis in the skeletal muscle of WT mice, but not AMPKα1-/- mice. CONCLUSIONS AMPKα1 is an important mediator for the beneficial effects of raspberry through alleviating inflammatory responses and sensitizing insulin signaling in skeletal muscle of HFD-fed mice.
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Affiliation(s)
- Liang Zhao
- Department of Animal Sciences, Nutrigenomics and Growth Biology laboratory, Washington State University, Pullman, WA, 99164, USA
| | - Tiande Zou
- Department of Animal Sciences, Nutrigenomics and Growth Biology laboratory, Washington State University, Pullman, WA, 99164, USA
- Jiangxi Province Key Laboratory of Animal Nutrition, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China
| | - Noe Alberto Gomez
- Department of Animal Sciences, Nutrigenomics and Growth Biology laboratory, Washington State University, Pullman, WA, 99164, USA
| | - Bo Wang
- Department of Animal Sciences, Nutrigenomics and Growth Biology laboratory, Washington State University, Pullman, WA, 99164, USA
| | - Mei-Jun Zhu
- School of Food Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Min Du
- Department of Animal Sciences, Nutrigenomics and Growth Biology laboratory, Washington State University, Pullman, WA, 99164, USA.
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100194, China.
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23
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Lepretti M, Martucciello S, Burgos Aceves MA, Putti R, Lionetti L. Omega-3 Fatty Acids and Insulin Resistance: Focus on the Regulation of Mitochondria and Endoplasmic Reticulum Stress. Nutrients 2018. [PMID: 29538286 PMCID: PMC5872768 DOI: 10.3390/nu10030350] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial dysfunction and endoplasmic reticulum (ER) stress have been suggested to play a key role in insulin resistance development. Reactive oxygen species (ROS) production and lipid accumulation due to mitochondrial dysfunction seemed to be important mechanisms leading to cellular insulin resistance. Moreover, mitochondria are functionally and structurally linked to ER, which undergoes stress in conditions of chronic overnutrition, activating the unfolded protein response, which in turn activates the principal inflammatory pathways that impair insulin action. Among the nutrients, dietary fats are believed to play key roles in insulin resistance onset. However, not all dietary fats exert the same effects on cellular energy metabolism. Dietary omega 3 polyunsaturated fatty acids (PUFA) have been suggested to counteract insulin resistance development by modulating mitochondrial bioenergetics and ER stress. In the current review, we summarized current knowledge on the role played by mitochondrial and ER stress in inflammation and insulin resistance onset, focusing on the modulation role of omega 3 PUFA on these stress pathways. Understanding the mechanisms by which omega 3 PUFA modulates cellular metabolism and insulin resistance in peripheral tissues may provide additional details on the potential impact of omega 3 PUFA on metabolic function and the management of insulin resistance in humans.
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Affiliation(s)
- Marilena Lepretti
- Department of Chemistry and Biology, University of Salerno, Via Giovanni Paolo II, 132, Fisciano 84084, Italy.
| | - Stefania Martucciello
- Department of Chemistry and Biology, University of Salerno, Via Giovanni Paolo II, 132, Fisciano 84084, Italy.
| | - Mario Alberto Burgos Aceves
- Department of Chemistry and Biology, University of Salerno, Via Giovanni Paolo II, 132, Fisciano 84084, Italy.
| | - Rosalba Putti
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte S.Angelo, Edificio 7, via Cintia 26, 80126 Napoli, Italy.
| | - Lillà Lionetti
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte S.Angelo, Edificio 7, via Cintia 26, 80126 Napoli, Italy.
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24
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Silvestri E, Cioffi F, De Matteis R, Senese R, de Lange P, Coppola M, Salzano AM, Scaloni A, Ceccarelli M, Goglia F, Lanni A, Moreno M, Lombardi A. 3,5-Diiodo-L-Thyronine Affects Structural and Metabolic Features of Skeletal Muscle Mitochondria in High-Fat-Diet Fed Rats Producing a Co-adaptation to the Glycolytic Fiber Phenotype. Front Physiol 2018; 9:194. [PMID: 29593557 PMCID: PMC5854997 DOI: 10.3389/fphys.2018.00194] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 02/23/2018] [Indexed: 11/22/2022] Open
Abstract
Hyperlipidemic state-associated perturbations in the network of factors controlling mitochondrial functions, i. e., morphogenesis machinery and metabolic sensor proteins, produce metabolic inflexibility, insulin resistance and reduced oxidative capacity in skeletal muscle. Moreover, intramyocellular lipid (IMCL) accumulation leads to tissue damage and inflammation. The administration of the naturally occurring metabolite 3,5-diiodo-L-thyronine (T2) with thyromimetic actions to high fat diet (HFD)-fed rats exerts a systemic hypolipidemic effect, which produces a lack of IMCL accumulation, a shift toward glycolytic fibers and amelioration of insulin sensitivity in gastrocnemius muscle. In this study, an integrated approach combining large-scale expression profile and functional analyses was used to characterize the response of skeletal muscle mitochondria to T2 during a HFD regimen. Long-term T2 administration to HDF rats induced a glycolytic phenotype of gastrocnemius muscle as well as an adaptation of mitochondria to the fiber type, with a decreased representation of enzymes involved in mitochondrial oxidative metabolism. At the same time, T2 stimulated the activity of individual respiratory complex I, IV, and V. Moreover, T2 prevented the HFD-associated increase in the expression of peroxisome proliferative activated receptor γ coactivator-1α and dynamin-1-like protein as well as mitochondrial morphological aberrations, favoring the appearance of tubular and tethered organelles in the intermyofibrillar regions. Remarkably, T2 reverted the HDF-associated expression pattern of proinflammatory factors, such as p65 subunit of NF-kB, and increased the fiber-specific immunoreactivity of adipose differentiation–related protein in lipid droplets. All together, these results further support a role of T2 in counteracting in vivo some of the HFD-induced impairment in structural/metabolic features of skeletal muscle by impacting the mitochondrial phenotype.
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Affiliation(s)
- Elena Silvestri
- Department of Science and Technologies, University of Sannio, Benevento, Italy
| | - Federica Cioffi
- Department of Science and Technologies, University of Sannio, Benevento, Italy
| | - Rita De Matteis
- Department of Biomolecular Sciences, Urbino University, Urbino, Italy
| | - Rosalba Senese
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, Caserta, Italy
| | - Pieter de Lange
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, Caserta, Italy
| | - Maria Coppola
- Department of Science and Technologies, University of Sannio, Benevento, Italy
| | - Anna M Salzano
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Andrea Scaloni
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Naples, Italy
| | - Michele Ceccarelli
- Department of Science and Technologies, University of Sannio, Benevento, Italy
| | - Fernando Goglia
- Department of Science and Technologies, University of Sannio, Benevento, Italy
| | - Antonia Lanni
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania, Caserta, Italy
| | - Maria Moreno
- Department of Science and Technologies, University of Sannio, Benevento, Italy
| | - Assunta Lombardi
- Department of Biology, University of Naples Federico II, Naples, Italy
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25
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Carpentier AC. Abnormal Myocardial Dietary Fatty Acid Metabolism and Diabetic Cardiomyopathy. Can J Cardiol 2018; 34:605-614. [PMID: 29627307 DOI: 10.1016/j.cjca.2017.12.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/08/2017] [Accepted: 12/19/2017] [Indexed: 12/13/2022] Open
Abstract
Patients with diabetes are at very high risk of hospitalization and death from heart failure. Increased prevalence of coronary heart disease, hypertension, autonomic neuropathy, and kidney failure all play a role in this increased risk. However, cardiac metabolic abnormalities are now recognized to play a role in this increased risk. Increased reliance on fatty acids to produce energy might predispose the diabetic heart to oxidative stress and ischemic damage. Intramyocellular accumulation of toxic lipid metabolites leads to a number of cellular abnormalities that might also contribute to cardiac remodelling and cardiac dysfunction. However, fatty acid availability from circulation and from intracellular lipid droplets to fuel the heart is critical to maintain its function. Fatty acids delivery to the heart is very complex and includes plasma nonesterified fatty acid flux as well as triglyceride-rich lipoprotein-mediated transport. Although many studies have shown a cross-sectional association between enhanced fatty acid delivery to the heart and reduction in left ventricular function in subjects with prediabetes and diabetes, these mechanisms change very rapidly during type 2 diabetes treatment. The present review focuses on the role of fatty acids in cardiac function, with particular emphasis on the possible role of early abnormalities of dietary fatty acid metabolism in the development of diabetic cardiomyopathy.
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Affiliation(s)
- André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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26
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Meng ZX, Tao W, Sun J, Wang Q, Mi L, Lin JD. Uncoupling Exercise Bioenergetics From Systemic Metabolic Homeostasis by Conditional Inactivation of Baf60 in Skeletal Muscle. Diabetes 2018; 67:85-97. [PMID: 29092888 PMCID: PMC5741141 DOI: 10.2337/db17-0367] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/24/2017] [Indexed: 12/19/2022]
Abstract
Impaired skeletal muscle energy metabolism is linked to the pathogenesis of insulin resistance and glucose intolerance in type 2 diabetes. The contractile and metabolic properties of myofibers exhibit a high degree of heterogeneity and plasticity. The regulatory circuitry underpinning skeletal muscle energy metabolism is critically linked to exercise endurance and systemic homeostasis. Recent work has identified the Baf60 subunits of the SWI/SNF chromatin-remodeling complex as powerful regulators of the metabolic gene programs. However, their role in integrating myofiber energy metabolism with exercise endurance and metabolic physiology remains largely unknown. In this study, we conditionally inactivated Baf60a, Baf60c, or both in mature skeletal myocytes to delineate their contribution to muscle bioenergetics and metabolic physiology. Our work revealed functional redundancy between Baf60a and Baf60c in maintaining oxidative and glycolytic metabolism in skeletal myofibers and exercise endurance. Unexpectedly, mice lacking these two factors in skeletal muscle were protected from diet-induced and age-associated metabolic disorders. Transcriptional profiling analysis identified the muscle thermogenic gene program and myokine secretion as key pathways that integrate myofiber metabolism with systemic energy balance. As such, Baf60 deficiency in skeletal muscle illustrates a surprising disconnect between exercise endurance and systemic metabolic homeostasis.
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Affiliation(s)
- Zhuo-Xian Meng
- Life Sciences Institute, University of Michigan, and Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Department of Pathology and Pathophysiology, Key Laboratory of Disease Proteomics of Zhejiang Province, and Chronic Disease Research Institute of School of Public Health, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Weiwei Tao
- Life Sciences Institute, University of Michigan, and Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Jingxia Sun
- Life Sciences Institute, University of Michigan, and Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Department of Pathology and Pathophysiology, Key Laboratory of Disease Proteomics of Zhejiang Province, and Chronic Disease Research Institute of School of Public Health, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qiuyu Wang
- Life Sciences Institute, University of Michigan, and Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Lin Mi
- Life Sciences Institute, University of Michigan, and Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Jiandie D Lin
- Life Sciences Institute, University of Michigan, and Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
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27
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Insulin Resistance, Obesity and Lipotoxicity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 960:277-304. [PMID: 28585204 DOI: 10.1007/978-3-319-48382-5_12] [Citation(s) in RCA: 273] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Lipotoxicity , originally used to describe the destructive effects of excess fat accumulation on glucose metabolism, causes functional impairments in several metabolic pathways, both in adipose tissue and peripheral organs, like liver, heart, pancreas and muscle. Lipotoxicity has roles in insulin resistance and pancreatic beta cell dysfunction. Increased circulating levels of lipids and the metabolic alterations in fatty acid utilization and intracellular signaling, have been related to insulin resistance in muscle and liver. Different pathways, like novel protein kinase c pathways and the JNK-1 pathway are involved as the mechanisms of how lipotoxicity leads to insulin resistance in nonadipose tissue organs, such as liver and muscle. Mitochondrial dysfunction plays a role in the pathogenesis of insulin resistance. Endoplasmic reticulum stress, through mainly increased oxidative stress, also plays important role in the etiology of insulin resistance, especially seen in non-alcoholic fatty liver disease. Visceral adiposity and insulin resistance both increase the cardiometabolic risk and lipotoxicity seems to play a crucial role in the pathophysiology of these associations.
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28
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Glucose Sensing by Skeletal Myocytes Couples Nutrient Signaling to Systemic Homeostasis. Mol Cell 2017; 66:332-344.e4. [PMID: 28475869 PMCID: PMC5489118 DOI: 10.1016/j.molcel.2017.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 02/07/2017] [Accepted: 04/05/2017] [Indexed: 12/21/2022]
Abstract
Skeletal muscle is a major site of postprandial glucose disposal. Inadequate insulin action in skeletal myocytes contributes to hyperglycemia in diabetes. Although glucose is known to stimulate insulin secretion by β cells, whether it directly engages nutrient signaling pathways in skeletal muscle to maintain systemic glucose homeostasis remains largely unexplored. Here we identified the Baf60c-Deptor-AKT pathway as a target of muscle glucose sensing that augments insulin action in skeletal myocytes. Genetic activation of this pathway improved postprandial glucose disposal in mice, whereas its muscle-specific ablation impaired insulin action and led to postprandial glucose intolerance. Mechanistically, glucose triggers KATP channel-dependent calcium signaling, which promotes HDAC5 phosphorylation and nuclear exclusion, leading to Baf60c induction and insulin-independent AKT activation. This pathway is engaged by the anti-diabetic sulfonylurea drugs to exert their full glucose-lowering effects. These findings uncover an unexpected mechanism of glucose sensing in skeletal myocytes that contributes to homeostasis and therapeutic action.
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29
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Huang Y, Gao S, Chen J, Albrecht E, Zhao R, Yang X. Maternal butyrate supplementation induces insulin resistance associated with enhanced intramuscular fat deposition in the offspring. Oncotarget 2017; 8:13073-13084. [PMID: 28055958 PMCID: PMC5355078 DOI: 10.18632/oncotarget.14375] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/01/2016] [Indexed: 12/20/2022] Open
Abstract
Maternal nutrition is important for the risk of the offspring to develop insulin resistance and adiposity later in life. The study was undertaken to determine effects of maternal butyrate supplementation on lipid metabolism and insulin sensitivity in the offspring skeletal muscle. The offspring of rats, fed a control diet or a butyrate diet (1% sodium butyrate) throughout gestation and lactation, was studied at weaning and at 60 days of age. The offspring of dams fed a butyrate diet had higher HOMA-insulin resistance and impaired glucose tolerance. This was associated with elevated mRNA and protein expressions of lipogenic genes and decreased amounts of lipolytic enzyme. Simultaneously, enhanced acetylation of histone H3 lysine 9 and histone H3 lysine 27 modification on the lipogenic genes in skeletal muscle of adult offspring was observed. Higher concentration of serum insulin and intramuscular triglyceride in skeletal muscle of offspring from the butyrate group at weaning were accompanied by increasing levels of lipogenic genes and enrichment of acetylation of histone H3 lysine 27. Maternal butyrate supplementation leads to insulin resistance and ectopic lipid accumulation in skeletal muscle of offspring, indicating the importance of short chain fatty acids in the maternal diet on lipid metabolism.
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Affiliation(s)
- Yanping Huang
- Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Shixing Gao
- Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Jinglong Chen
- Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Elke Albrecht
- Leibniz Institute for Farm Animal Biology, Institute for Muscle Biology and Growth, Dummerstorf, Germany
| | - Ruqian Zhao
- Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Xiaojing Yang
- Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, P. R. China
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30
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Kimmel AR, Sztalryd C. The Perilipins: Major Cytosolic Lipid Droplet-Associated Proteins and Their Roles in Cellular Lipid Storage, Mobilization, and Systemic Homeostasis. Annu Rev Nutr 2017; 36:471-509. [PMID: 27431369 DOI: 10.1146/annurev-nutr-071813-105410] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discovery by Dr. Constantine Londos of perilipin 1, the major scaffold protein at the surface of cytosolic lipid droplets in adipocytes, marked a fundamental conceptual change in the understanding of lipolytic regulation. Focus then shifted from the enzymatic activation of lipases to substrate accessibility, mediated by perilipin-dependent protein sequestration and recruitment. Consequently, the lipid droplet became recognized as a unique, metabolically active cellular organelle and its surface as the active site for novel protein-protein interactions. A new area of investigation emerged, centered on lipid droplets' biology and their role in energy homeostasis. The perilipin family is of ancient origin and has expanded to include five mammalian genes and a growing list of evolutionarily conserved members. Universally, the perilipins modulate cellular lipid storage. This review provides a summary that connects the perilipins to both cellular and whole-body homeostasis.
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Affiliation(s)
- Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, Maryland 20892;
| | - Carole Sztalryd
- The Geriatric Research Education and Clinical Center, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201.,Division of Endocrinology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201;
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31
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Callahan ZJ, Oxendine MJ, Schaeffer PJ. Intramuscular triglyceride content precedes impaired glucose metabolism without evidence for mitochondrial dysfunction during early development of a diabetic phenotype. Appl Physiol Nutr Metab 2017; 42:963-972. [PMID: 28538106 DOI: 10.1139/apnm-2016-0685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The incidence of type 2 diabetes is highly correlated with obesity; however, there is a lack of research elucidating the temporal progression. Transgenic FVB/N UCP-dta mice, which develop a diabetic phenotype, and their nontransgenic littermates were fed either a high-fat or normal-chow diet and were studied at 6, 9, 12, 15, 18, 21, and 24 weeks of age to test the hypothesis that increased lipid accumulation in skeletal muscle causes mitochondrial dysfunction, leading to the development of insulin resistance. Body composition, intramuscular triglyceride (IMTG) content, glucose metabolism, and mitochondrial function were measured to determine if IMTG drove mitochondrial dysfunction, leading to the development of type 2 diabetes. High-fat-fed transgenic mice had a significantly greater body mass, lipid mass, and IMTG content beginning early in the experiment. Glucose tolerance tests revealed that high-fat-fed transgenic mice developed a significantly insulin resistant response compared with the other 3 groups toward the end of the time course while plasma insulin was elevated very early in the time course. There was no significant difference in several measures of metabolic function throughout the time course. Long-term high-fat feeding in transgenic mice produced increases in IMTG, adiposity, body mass, and plasma insulin accompanied by decreases in glucose metabolism, but did not reveal any deficits in mitochondrial function or regulation during the early stage of the development of type 2 diabetes. It does not appear that lipotoxicity is driving defects in mitochondrial function prior to the onset of insulin resistance.
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Affiliation(s)
- Zachary J Callahan
- Department of Biology, Miami University, Oxford, OH 45056, USA.,Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Michael J Oxendine
- Department of Biology, Miami University, Oxford, OH 45056, USA.,Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Paul J Schaeffer
- Department of Biology, Miami University, Oxford, OH 45056, USA.,Department of Biology, Miami University, Oxford, OH 45056, USA
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32
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Grenier-Larouche T, Carreau AM, Carpentier AC. Early Metabolic Improvement After Bariatric Surgery: The First Steps Toward Remission of Type 2 Diabetes. Can J Diabetes 2017; 41:418-425. [PMID: 28318939 DOI: 10.1016/j.jcjd.2016.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 08/23/2016] [Accepted: 10/24/2016] [Indexed: 02/06/2023]
Abstract
The introduction of bariatric surgery into clinical practice in the 1980s was followed by a relatively long watch-and-wait period before the very rapid accumulation of scientific literature, over the past decade, concerning its clinical effectiveness and safety and its mechanisms of action in the treatment of obesity. These surgical procedures now emerge as the most effective therapeutic modality to induce long-term remission of type 2 diabetes. Recent research has shed light on the potential mechanisms leading to the profound improvement of glucose homeostasis following most bariatric surgery procedures. These mechanisms can be classified as weight loss dependent and independent, both playing sequential and then synergistic antidiabetes roles. Many groups, including our own, have contributed to our understanding of the relative roles of these mechanisms at differing time periods following these procedures. Here we summarize what we currently know about the mechanisms underlying the very rapid, weight loss-independent improvement in glucose homeostasis after bariatric surgery. Beyond its impact in the field of bariatric surgery, this new knowledge about the very rapid in vivo "reverse engineering" of type 2 diabetes actually provides unique insights into the intricate and complex mechanisms linking nutrition and obesity with the development of this disease.
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Affiliation(s)
- Thomas Grenier-Larouche
- Department of Medicine, Division of Endocrinology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke (CHUS), Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Anne-Marie Carreau
- Department of Medicine, Division of Endocrinology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke (CHUS), Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - André C Carpentier
- Department of Medicine, Division of Endocrinology, Centre de recherche du Centre hospitalier universitaire de Sherbrooke (CHUS), Université de Sherbrooke, Sherbrooke, Quebec, Canada.
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33
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Wu W, Feng J, Jiang D, Zhou X, Jiang Q, Cai M, Wang X, Shan T, Wang Y. AMPK regulates lipid accumulation in skeletal muscle cells through FTO-dependent demethylation of N 6-methyladenosine. Sci Rep 2017; 7:41606. [PMID: 28176824 PMCID: PMC5296945 DOI: 10.1038/srep41606] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 12/22/2016] [Indexed: 11/28/2022] Open
Abstract
Skeletal muscle plays important roles in whole-body energy homeostasis. Excessive skeletal muscle lipid accumulation is associated with some metabolic diseases such as obesity and Type 2 Diabetes. The energy sensor AMPK (AMP-activated protein kinase) is a key regulator of skeletal muscle lipid metabolism, but the precise regulatory mechanism remains to be elucidated. Here, we provide a novel mechanism by which AMPK regulates skeletal muscle lipid accumulation through fat mass and obesity-associated protein (FTO)-dependent demethylation of N6-methyladenosine (m6A). We confirmed an inverse correlation between AMPK and skeletal muscle lipid content. Moreover, inhibition of AMPK enhanced lipid accumulation, while activation of AMPK reduced lipid accumulation in skeletal muscle cells. Notably, we found that mRNA m6A methylation levels were inversely correlated with lipid content in skeletal muscle. Furthermore, AMPK positively regulated the m6A methylation levels of mRNA, which could negatively regulate lipid accumulation in C2C12. At the molecular level, we demonstrated that AMPK regulated lipid accumulation in skeletal muscle cells by regulating FTO expression and FTO-dependent demethylation of m6A. Together, these results provide a novel regulatory mechanism of AMPK on lipid metabolism in skeletal muscle cells and suggest the possibility of controlling skeletal muscle lipid deposition by targeting AMPK or using m6A related drugs.
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Affiliation(s)
- Weiche Wu
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Jie Feng
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Denghu Jiang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Xihong Zhou
- Institute of Subtropical Agriculture, The Chinese Academy of Science, Changsha, Hunan 410125, P. R. China
| | - Qin Jiang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Min Cai
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Xinxia Wang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Tizhong Shan
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Yizhen Wang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
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34
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Brøns C, Grunnet LG. MECHANISMS IN ENDOCRINOLOGY: Skeletal muscle lipotoxicity in insulin resistance and type 2 diabetes: a causal mechanism or an innocent bystander? Eur J Endocrinol 2017; 176:R67-R78. [PMID: 27913612 DOI: 10.1530/eje-16-0488] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/19/2016] [Accepted: 09/14/2016] [Indexed: 12/11/2022]
Abstract
Dysfunctional adipose tissue is associated with an increased risk of developing type 2 diabetes (T2D). One characteristic of a dysfunctional adipose tissue is the reduced expandability of the subcutaneous adipose tissue leading to ectopic storage of fat in organs and/or tissues involved in the pathogenesis of T2D that can cause lipotoxicity. Accumulation of lipids in the skeletal muscle is associated with insulin resistance, but the majority of previous studies do not prove any causality. Most studies agree that it is not the intramuscular lipids per se that causes insulin resistance, but rather lipid intermediates such as diacylglycerols, fatty acyl-CoAs and ceramides and that it is the localization, composition and turnover of these intermediates that play an important role in the development of insulin resistance and T2D. Adipose tissue is a more active tissue than previously thought, and future research should thus aim at examining the exact role of lipid composition, cellular localization and the dynamics of lipid turnover on the development of insulin resistance. In addition, ectopic storage of fat has differential impact on various organs in different phenotypes at risk of developing T2D; thus, understanding how adipogenesis is regulated, the interference with metabolic outcomes and what determines the capacity of adipose tissue expandability in distinct population groups is necessary. This study is a review of the current literature on the adipose tissue expandability hypothesis and how the following ectopic lipid accumulation as a consequence of a limited adipose tissue expandability may be associated with insulin resistance in muscle and liver.
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Affiliation(s)
- Charlotte Brøns
- Department of Endocrinology (Diabetes and Metabolism)Rigshospitalet, Copenhagen, Denmark
| | - Louise Groth Grunnet
- Department of Endocrinology (Diabetes and Metabolism)Rigshospitalet, Copenhagen, Denmark
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Yamamoto T, Takabatake Y, Takahashi A, Kimura T, Namba T, Matsuda J, Minami S, Kaimori JY, Matsui I, Matsusaka T, Niimura F, Yanagita M, Isaka Y. High-Fat Diet-Induced Lysosomal Dysfunction and Impaired Autophagic Flux Contribute to Lipotoxicity in the Kidney. J Am Soc Nephrol 2016; 28:1534-1551. [PMID: 27932476 DOI: 10.1681/asn.2016070731] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 11/07/2016] [Indexed: 12/27/2022] Open
Abstract
Excessive fat intake contributes to the progression of metabolic diseases via cellular injury and inflammation, a process termed lipotoxicity. Here, we investigated the role of lysosomal dysfunction and impaired autophagic flux in the pathogenesis of lipotoxicity in the kidney. In mice, a high-fat diet (HFD) resulted in an accumulation of phospholipids in enlarged lysosomes within kidney proximal tubular cells (PTCs). In isolated PTCs treated with palmitic acid, autophagic degradation activity progressively stagnated in association with impaired lysosomal acidification and excessive lipid accumulation. Pulse-chase experiments revealed that the accumulated lipids originated from cellular membranes. In mice with induced PTC-specific ablation of autophagy, PTCs of HFD-mice exhibited greater accumulation of ubiquitin-positive protein aggregates normally removed by autophagy than did PTCs of mice fed a normal diet. Furthermore, HFD-mice had no capacity to augment autophagic activity upon another pathologic stress. Autophagy ablation also exaggerated HFD-induced mitochondrial dysfunction and inflammasome activation. Moreover, renal ischemia-reperfusion induced greater injury in HFD-mice than in mice fed a normal diet, and ablation of autophagy further exacerbated this effect. Finally, we detected similarly enhanced phospholipid accumulation in enlarged lysosomes and impaired autophagic flux in the kidneys of obese patients compared with nonobese patients. These findings provide key insights regarding the pathophysiology of lipotoxicity in the kidney and clues to a novel treatment for obesity-related kidney diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Jun-Ya Kaimori
- Advanced Technology for Transplantation, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | | | - Taiji Matsusaka
- Institute of Medical Sciences and Department of Molecular Life Sciences and
| | - Fumio Niimura
- Department of Pediatrics, Tokai University School of Medicine, Isehara, Kanagawa, Japan; and
| | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Rossi FE, Diniz TA, Fortaleza ACS, Neves LM, Picolo MR, Monteiro PA, Buonani C, Lira FS, Freitas IF. Concurrent Training Promoted Sustained Anti-atherogenic Benefits in the Fasting Plasma Triacylglycerolemia of Postmenopausal Women at 1-Year Follow-up. J Strength Cond Res 2016; 32:3564-3573. [PMID: 27893473 DOI: 10.1519/jsc.0000000000001732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Rossi, FE, Diniz, TA, Fortaleza, ACS, Neves, LM, Picolo, MR, Monteiro, PA, Buonani, C, Lira, FS, and Freitas, IF Jr. Concurrent training promoted sustained anti-atherogenic benefits in the fasting plasma triacylglycerolemia of postmenopausal women at 1-year follow-up. J Strength Cond Res 32(12): 3573-3582, 2018-The aim of this study was to compare the effects of aerobic and concurrent training (aerobic plus strength training) on the lipid profiles of normotriacylglycerolemic and hypertriacylglycerolemic postmenopausal women and to verify whether the benefits of aerobic and concurrent training were sustained after 1 year. Total cholesterol, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol, triacylglycerol (TAG), and glucose were assessed in 46 normotriacylglycerolemic (TAG < 150 mg·dl) postmenopausal women divided into 3 groups: aerobic training, concurrent training (CT), and a control group. For CT group, hypertriacylglycerolemic postmenopausal women were recruited (TAG ≥ 150 mg·dl, n = 14). Total daily caloric consumption and free-living physical activity were evaluated by dietary questionnaires and accelerometer, respectively, and fat mass by DXA. In 16 weeks, CT was effective in increasing HDL-c (normotriacylglycerolemic: pre = 57.1 ± 17.3 mg·dl × post = 64.3 ± 16.1 mg·dl p = 0.020 and hypertriacylglycerolemic: pre = 44.7 ± 9.6 mg·dl × post = 50.3 ± 15.3 mg·dl; p = 0.012) and reducing the atherogenic index in normotriacylglycerolemic (pre = 3.6 ± 0.9 mg·dl × post = 3.0 ± 0.6 mg·dl; p = 0.003) and hypertriacylglycerolemic (pre = 5.2 ± 1.1 mg·dl × post = 4.7 ± 1.2 mg·dl; p = 0.018) postmenopausal women. In addition, the effects were sustained at the 1-year follow-up only among the hypertriacylglycerolemic postmenopausal women. The anti-atherogenic status in normotriacylglycerolemic and hypertriacylglycerolemic postmenopausal women was changed by CT but without significant differences between groups. Furthermore, these benefits are sustained at the 1-year follow-up among the hypertriacylglycerolemic subjects.
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Affiliation(s)
- Fabrício E Rossi
- Department of Physical Education, Institute of Bioscience, University Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Tiego A Diniz
- Department of Physical Education, Institute of Bioscience, University Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Ana C S Fortaleza
- Department of Physical Education, Institute of Bioscience, University Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Lucas M Neves
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | | | - Paula A Monteiro
- Department of Physical Education, Institute of Bioscience, University Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Camila Buonani
- Physical Education, University Estadual Paulista, Presidente Prudente, São Paulo, Brazil
| | - Fábio S Lira
- Exercise and Immunometabolism Research Group, Department of Physical Education, University Estadual Paulista (UNESP), Presidente Prudente, São Paulo, Brazil
| | - Ismael F Freitas
- Physical Education, University Estadual Paulista, Presidente Prudente, São Paulo, Brazil
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Morris EM, Meers GME, Koch LG, Britton SL, Fletcher JA, Fu X, Shankar K, Burgess SC, Ibdah JA, Rector RS, Thyfault JP. Aerobic capacity and hepatic mitochondrial lipid oxidation alters susceptibility for chronic high-fat diet-induced hepatic steatosis. Am J Physiol Endocrinol Metab 2016; 311:E749-E760. [PMID: 27600823 PMCID: PMC5241560 DOI: 10.1152/ajpendo.00178.2016] [Citation(s) in RCA: 25] [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] [Received: 05/03/2016] [Accepted: 08/30/2016] [Indexed: 12/24/2022]
Abstract
Rats selectively bred for high capacity running (HCR) or low capacity running (LCR) display divergence for intrinsic aerobic capacity and hepatic mitochondrial oxidative capacity, both factors associated with susceptibility for nonalcoholic fatty liver disease. Here, we tested if HCR and LCR rats display differences in susceptibility for hepatic steatosis after 16 wk of high-fat diets (HFD) with either 45% or 60% of kcals from fat. HCR rats were protected against HFD-induced hepatic steatosis, whereas only the 60% HFD induced steatosis in LCR rats, as marked by a doubling of liver triglycerides. Hepatic complete fatty acid oxidation (FAO) and mitochondrial respiratory capacity were all lower in LCR compared with HCR rats. LCR rats also displayed lower hepatic complete and incomplete FAO in the presence of etomoxir, suggesting a reduced role for noncarnitine palmitoyltransferase-1-mediated lipid catabolism in LCR versus HCR rats. Hepatic complete FAO and mitochondrial respiration were largely unaffected by either chronic HFD; however, 60% HFD feeding markedly reduced 2-pyruvate oxidation, a marker of tricarboxylic acid (TCA) cycle flux, and mitochondrial complete FAO only in LCR rats. LCR rats displayed lower levels of hepatic long-chain acylcarnitines than HCR rats but maintained similar levels of hepatic acetyl-carnitine levels, further supporting lower rates of β-oxidation, and TCA cycle flux in LCR than HCR rats. Finally, only LCR rats displayed early reductions in TCA cycle genes after the acute initiation of a HFD. In conclusion, intrinsically high aerobic capacity confers protection against HFD-induced hepatic steatosis through elevated hepatic mitochondrial oxidative capacity.
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Affiliation(s)
- E Matthew Morris
- Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas
| | - Grace M E Meers
- Medicine and Division of Gastroenterology and Hepatology, University of Missouri, Columbia, Missouri
| | - Lauren G Koch
- Anesthesiology, University of Michigan, Ann Arbor, Michigan
| | | | - Justin A Fletcher
- Pharmacology and Advanced Imaging Research, University of Texas Southwestern, Dallas, Texas
| | - Xiaorong Fu
- Pharmacology and Advanced Imaging Research, University of Texas Southwestern, Dallas, Texas
| | - Kartik Shankar
- Arkansas Children's Nutrition Center and the Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Shawn C Burgess
- Pharmacology and Advanced Imaging Research, University of Texas Southwestern, Dallas, Texas
| | - Jamal A Ibdah
- Medicine and Division of Gastroenterology and Hepatology, University of Missouri, Columbia, Missouri
| | - R Scott Rector
- Medicine and Division of Gastroenterology and Hepatology, University of Missouri, Columbia, Missouri; Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Research Service, Harry S. Truman Memorial Veterans Affairs Hospital, Columbia, Missouri
| | - John P Thyfault
- Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas; Research Service, Kansas City Veterans Affairs Medical Center, Kansas City, Missourit; and
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Affourtit C. Mitochondrial involvement in skeletal muscle insulin resistance: A case of imbalanced bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1678-93. [PMID: 27473535 DOI: 10.1016/j.bbabio.2016.07.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/19/2016] [Accepted: 07/23/2016] [Indexed: 12/16/2022]
Abstract
Skeletal muscle insulin resistance in obesity associates with mitochondrial dysfunction, but the causality of this association is controversial. This review evaluates mitochondrial models of nutrient-induced muscle insulin resistance. It transpires that all models predict that insulin resistance arises as a result of imbalanced cellular bioenergetics. The nature and precise origin of the proposed insulin-numbing molecules differ between models but all species only accumulate when metabolic fuel supply outweighs energy demand. This observation suggests that mitochondrial deficiency in muscle insulin resistance is not merely owing to intrinsic functional defects, but could instead be an adaptation to nutrient-induced changes in energy expenditure. Such adaptive effects are likely because muscle ATP supply is fully driven by energy demand. This market-economic control of myocellular bioenergetics offers a mechanism by which insulin-signalling deficiency can cause apparent mitochondrial dysfunction, as insulin resistance lowers skeletal muscle anabolism and thus dampens ATP demand and, consequently, oxidative ATP synthesis.
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Affiliation(s)
- Charles Affourtit
- School of Biomedical and Healthcare Sciences, Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth University, Drake Circus, PL4 8AA Plymouth, UK.
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A mitochondrial-targeted ubiquinone modulates muscle lipid profile and improves mitochondrial respiration in obesogenic diet-fed rats. Br J Nutr 2016; 115:1155-66. [PMID: 26856891 DOI: 10.1017/s0007114515005528] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The prevalence of the metabolic syndrome components including abdominal obesity, dyslipidaemia and insulin resistance is increasing in both developed and developing countries. It is generally accepted that the development of these features is preceded by, or accompanied with, impaired mitochondrial function. The present study was designed to analyse the effects of a mitochondrial-targeted lipophilic ubiquinone (MitoQ) on muscle lipid profile modulation and mitochondrial function in obesogenic diet-fed rats. For this purpose, twenty-four young male Sprague-Dawley rats were divided into three groups and fed one of the following diets: (1) control, (2) high fat (HF) and (3) HF+MitoQ. After 8 weeks, mitochondrial function markers and lipid metabolism/profile modifications in skeletal muscle were measured. The HF diet was effective at inducing the major features of the metabolic syndrome--namely, obesity, hepatic enlargement and glucose intolerance. MitoQ intake prevented the increase in rat body weight, attenuated the increase in adipose tissue and liver weights and partially reversed glucose intolerance. At the muscle level, the HF diet induced moderate TAG accumulation associated with important modifications in the muscle phospholipid classes and in the fatty acid composition of total muscle lipid. These lipid modifications were accompanied with decrease in mitochondrial respiration. MitoQ intake corrected the lipid alterations and restored mitochondrial respiration. These results indicate that MitoQ protected obesogenic diet-fed rats from some features of the metabolic syndrome through its effects on muscle lipid metabolism and mitochondrial activity. These findings suggest that MitoQ is a promising candidate for future human trials in the metabolic syndrome prevention.
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Putti R, Migliaccio V, Sica R, Lionetti L. Skeletal Muscle Mitochondrial Bioenergetics and Morphology in High Fat Diet Induced Obesity and Insulin Resistance: Focus on Dietary Fat Source. Front Physiol 2016; 6:426. [PMID: 26834644 PMCID: PMC4719079 DOI: 10.3389/fphys.2015.00426] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 12/27/2015] [Indexed: 12/21/2022] Open
Abstract
It has been suggested that skeletal muscle mitochondria play a key role in high fat (HF) diet induced insulin resistance (IR). Two opposite views are debated on mechanisms by which mitochondrial function could be involved in skeletal muscle IR. In one theory, mitochondrial dysfunction is suggested to cause intramyocellular lipid accumulation leading to IR. In the second theory, excess fuel within mitochondria in the absence of increased energy demand stimulates mitochondrial oxidant production and emission, ultimately leading to the development of IR. Noteworthy, mitochondrial bioenergetics is strictly associated with the maintenance of normal mitochondrial morphology by maintaining the balance between the fusion and fission processes. A shift toward mitochondrial fission with reduction of fusion protein, mainly mitofusin 2, has been associated with reduced insulin sensitivity and inflammation in obesity and IR development. However, dietary fat source during chronic overfeeding differently affects mitochondrial morphology. Saturated fatty acids induce skeletal muscle IR and inflammation associated with fission phenotype, whereas ω-3 polyunsaturated fatty acids improve skeletal muscle insulin sensitivity and inflammation, associated with a shift toward mitochondrial fusion phenotype. The present minireview focuses on mitochondrial bioenergetics and morphology in skeletal muscle IR, with particular attention to the effect of different dietary fat sources on skeletal muscle mitochondria morphology and fusion/fission balance.
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Affiliation(s)
- Rosalba Putti
- Department of Biology, University of Naples "Federico II," Naples, Italy
| | | | - Raffaella Sica
- Department of Biology, University of Naples "Federico II," Naples, Italy
| | - Lillà Lionetti
- Department of Biology, University of Naples "Federico II," Naples, Italy
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Matczuk J, Zalewska A, Łukaszuk B, Knaś M, Maciejczyk M, Garbowska M, Ziembicka DM, Waszkiel D, Chabowski A, Żendzian-Piotrowska M, Kurek K. Insulin Resistance and Obesity Affect Lipid Profile in the Salivary Glands. J Diabetes Res 2016; 2016:8163474. [PMID: 27471733 PMCID: PMC4951584 DOI: 10.1155/2016/8163474] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 03/28/2016] [Accepted: 04/11/2016] [Indexed: 12/04/2022] Open
Abstract
In today's world wrong nutritional habits together with a low level of physical activity have given rise to the development of obesity and its comorbidity, insulin resistance. More specifically, many researches indicate that lipids are vitally involved in the onset of a peripheral tissue (e.g., skeletal muscle, heart, and liver) insulin resistance. Moreover, it seems that diabetes can also induce changes in respect of lipid composition of both the salivary glands and saliva. However, judging by the number of research articles, the salivary glands lipid profile still has not been sufficiently explored. In the current study we aim to assess the changes in the main lipid fractions, namely, triacylglycerols, phospholipids, free fatty acids, and diacylglycerols, in the parotid and the submandibular salivary glands of rats exposed to a 5-week high fat diet regimen. We observed that the high caloric fat diet caused a significant change in the salivary glands lipid composition, especially with respect to PH and TG, but not DAG or FFAs, classes. The observed reduction in PH concentration is an interesting phenomenon frequently signifying the atrophy and malfunctions in the saliva secreting organs. On the other hand, the increased accumulation of TG in the glands may be an important clinical manifestation of metabolic syndrome and type 2 diabetes mellitus.
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Affiliation(s)
- Jan Matczuk
- County Veterinary Inspection, 26B Zwycięstwa Street, 15-959 Białystok, Poland
| | - Anna Zalewska
- Department of Conservative Dentistry, Medical University of Bialystok, 1 Kilińskiego Street, 15-222 Białystok, Poland
| | - Bartłomiej Łukaszuk
- Department of Physiology, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Białystok, Poland
| | - Małgorzata Knaś
- Institute of Health Care Higher Vocational School, 10 Noniewicza Street, 16-400 Suwałki, Poland
| | - Mateusz Maciejczyk
- Students' Scientific Group “Stomatological Biochemistry”, Department of Conservative Dentistry, Medical University of Bialystok, 1 Kilińskiego Street, 15-222 Białystok, Poland
| | - Marta Garbowska
- Department of Hygiene, Epidemiology and Ergonomics, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Białystok, Poland
| | - Dominika M. Ziembicka
- Department of Public Health, Medical University of Bialystok, 1 Kilińskiego Street, 15-222 Białystok, Poland
| | - Danuta Waszkiel
- Department of Conservative Dentistry, Medical University of Bialystok, 1 Kilińskiego Street, 15-222 Białystok, Poland
| | - Adrian Chabowski
- Department of Physiology, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Białystok, Poland
| | - Małgorzata Żendzian-Piotrowska
- Department of Hygiene, Epidemiology and Ergonomics, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Białystok, Poland
| | - Krzysztof Kurek
- Department of Physiology, Medical University of Bialystok, 2C Mickiewicza Street, 15-222 Białystok, Poland
- *Krzysztof Kurek:
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Korth RM. LDL-Related Intolerance to Glucose, Diastolic Hypertension and Additive Effects of Smoking Were Found with Three Female Study Groups. Health (London) 2016. [DOI: 10.4236/health.2016.83026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Fibroblast Growth Factor 21 Suppresses Adipogenesis in Pig Intramuscular Fat Cells. Int J Mol Sci 2015; 17:ijms17010011. [PMID: 26703591 PMCID: PMC4730258 DOI: 10.3390/ijms17010011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 11/23/2015] [Accepted: 11/26/2015] [Indexed: 01/08/2023] Open
Abstract
Fibroblast growth factor 21 (FGF21) plays an important role in the treatment of disease associated with muscle insulin resistance which is characterized by various factors, such as intramuscular triglyceride (IMT) content. Studies have also shown that FGF21 inhibits triglyceride synthesis in vivo. However, the precise mechanism whereby FGF21 regulates triglyceride metabolism in intramuscular fat (IMF), which may influence the muscle insulin sensitivity, is not clearly understood. In order to understand the role of FGF21 in IMF deposition, we performed FGF21 overexpression in IMF cells by stable transfection. Our results showed that FGF21 inhibited the key adipogenesis gene mRNA expression of peroxisome proliferator-activated receptor gamma (PPARG), CCAAT/enhancer-binding protein (CEBP) family by reducing lysine-specific demethylase 1 (LSD1) expression which led to significant decline in lipid accumulation, and the result was confirmed by Western blot. Moreover, triggered by FGF21, parts of the adipokines—fatty acid-binding protein 4 (FABP4), glucose transporter 4 (GLUT4), adiponectin (ADIPOQ), and perilipin (PLIN1)—were also down-regulated. Furthermore, FGF21 gene expression was suppressed by transcription factor CEBP beta (CEBPB) which contributed strongly to triglyceride synthesis. Taken together, our study is the first to experimentally demonstrate FGF21 emerging as an efficient blockade of adipogenesis in IMF, thus also providing a new understanding of the mechanism whereby FGF21 improves insulin sensitivity.
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Urrutia RA, Kalinec F. Biology and pathobiology of lipid droplets and their potential role in the protection of the organ of Corti. Hear Res 2015; 330:26-38. [PMID: 25987503 PMCID: PMC5391798 DOI: 10.1016/j.heares.2015.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 12/20/2022]
Abstract
The current review article seeks to extend our understanding on the role of lipid droplets within the organ of Corti. In addition to presenting an overview of the current information about the origin, structure and function of lipid droplets we draw inferences from the collective body of knowledge about this cellular organelle to build a conceptual framework to better understanding their role in auditory function. This conceptual model considers that lipid droplets play a significant role in the synthesis, storage, and release of lipids and proteins for energetic use and/or modulating cell signaling pathways. We describe the role and mechanism by which LD play a role in human diseases, and we also review emerging data from our laboratory revealing the potential role of lipid droplets from Hensen cells in the auditory organ. We suggest that lipid droplets might help to develop rapidly and efficiently the resolution phase of inflammatory responses in the mammalian cochlea, preventing inflammatory damage of the delicate inner ear structures and, consequently, sensorineural hearing loss.
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Affiliation(s)
- Raul A Urrutia
- Epigenetics and Chromatin Dynamics Laboratory, Translational Epigenomic Program, Center for Individualized Medicine (CIM) Mayo Clinic, Rochester, MN 55905, USA
| | - Federico Kalinec
- Laboratory of Auditory Cell Biology, Department of Head & Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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45
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Diniz TA, Fortaleza ACS, Buonani C, Rossi FE, Neves LM, Lira FS, Freitas-Junior IF. Relationship between moderate-to-vigorous physical activity, abdominal fat and immunometabolic markers in postmenopausal women. Eur J Obstet Gynecol Reprod Biol 2015; 194:178-82. [PMID: 26412352 DOI: 10.1016/j.ejogrb.2015.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 06/08/2015] [Accepted: 09/07/2015] [Indexed: 12/17/2022]
Abstract
OBJECTS To assess the burden of levels of physical activity, non-esterified fatty acids (NEFA), triacylglycerol and abdominal fat on the immunometabolic profile of postmenopausal women. STUDY DESIGN Forty-nine postmenopausal women [mean age 59.43 (standard deviation 5.61) years] who did not undertake regular physical exercise participated in this study. Body composition was assessed using dual-energy X-ray absorptiometry, and levels of NEFA, tumour necrosis factor-α, adiponectin, insulin and triacylglycerol were assessed using fasting blood samples. The level of physical activity was assessed using an accelerometer (Actigraph GTX3x), and reported as counts/min, time spent undertaking sedentary activities and time spent undertaking moderate-to-vigorous physical activity (MVPA). The following conditions were considered to be risk factors: (i) sedentary lifestyle (<150min of MVPA per week); (ii) high level (above median) of abdominal fat; and (iii) hypertriacylglycerolaemia (<150mg/dl of triacylglycerol). RESULTS In comparison with active women, sedentary women had higher levels of body fat (%) (p=0.041) and NEFA (p=0.064). Women with higher levels of abdominal fat had impaired insulin resistance (HOMA-IR) (p=0.016) and spent more time undertaking sedentary activities (p=0.043). Moreover, the women with two risk factors or more had high levels of NEFA and HOMA-IR (p<0.05), as well as an eight-fold higher risk of a high level of NEFA, independent of age (p<0.05). No significant relationship was found between levels of physical activity, abdominal fat, tumour necrosis factor-α and adiponectin (p>0.05). CONCLUSION Postmenopausal women with a combination of hypertriacylglycerolaemia, a high level of abdominal fat and a sedentary lifestyle are more likely to have metabolic disturbances.
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Affiliation(s)
- T A Diniz
- Centre of Studies and Laboratory of Evaluation and Prescription of Motor Activities, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil; Exercise and Immunometabolism Research Group, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil.
| | - A C S Fortaleza
- Centre of Studies and Laboratory of Evaluation and Prescription of Motor Activities, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil
| | - C Buonani
- Centre of Studies and Laboratory of Evaluation and Prescription of Motor Activities, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil
| | - F E Rossi
- Centre of Studies and Laboratory of Evaluation and Prescription of Motor Activities, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil; Exercise and Immunometabolism Research Group, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil
| | - L M Neves
- Centre of Studies and Laboratory of Evaluation and Prescription of Motor Activities, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil
| | - F S Lira
- Exercise and Immunometabolism Research Group, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil
| | - I F Freitas-Junior
- Centre of Studies and Laboratory of Evaluation and Prescription of Motor Activities, Department of Physical Education, Sao Paulo State University, Presidente Prudente, SP, Brazil
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Stinkens R, Goossens GH, Jocken JWE, Blaak EE. Targeting fatty acid metabolism to improve glucose metabolism. Obes Rev 2015; 16:715-57. [PMID: 26179344 DOI: 10.1111/obr.12298] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/23/2015] [Accepted: 05/10/2015] [Indexed: 12/15/2022]
Abstract
Disturbances in fatty acid metabolism in adipose tissue, liver, skeletal muscle, gut and pancreas play an important role in the development of insulin resistance, impaired glucose metabolism and type 2 diabetes mellitus. Alterations in diet composition may contribute to prevent and/or reverse these disturbances through modulation of fatty acid metabolism. Besides an increased fat mass, adipose tissue dysfunction, characterized by an altered capacity to store lipids and an altered secretion of adipokines, may result in lipid overflow, systemic inflammation and excessive lipid accumulation in non-adipose tissues like liver, skeletal muscle and the pancreas. These impairments together promote the development of impaired glucose metabolism, insulin resistance and type 2 diabetes mellitus. Furthermore, intrinsic functional impairments in either of these organs may contribute to lipotoxicity and insulin resistance. The present review provides an overview of fatty acid metabolism-related pathways in adipose tissue, liver, skeletal muscle, pancreas and gut, which can be targeted by diet or food components, thereby improving glucose metabolism.
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Affiliation(s)
- R Stinkens
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - G H Goossens
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - J W E Jocken
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - E E Blaak
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center+, Maastricht, The Netherlands
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Zeng XY, Wang H, Bai F, Zhou X, Li SP, Ren LP, Sun RQ, Xue CCL, Jiang HL, Hu LH, Ye JM. Identification of matrine as a promising novel drug for hepatic steatosis and glucose intolerance with HSP72 as an upstream target. Br J Pharmacol 2015; 172:4303-18. [PMID: 26040411 DOI: 10.1111/bph.13209] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 05/14/2015] [Accepted: 06/02/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Matrine is a small molecule drug used in humans for the treatment of chronic viral infections and tumours in the liver with little adverse effects. The present study investigated its therapeutic efficacy for insulin resistance and hepatic steatosis in high-fat-fed mice. EXPERIMENTAL APPROACH C57BL/J6 mice were fed a chow or high-fat diet for 10 weeks and then treated with matrine or metformin for 4 weeks. The effects on lipid metabolism and glucose tolerance were evaluated. KEY RESULTS Our results first showed that matrine reduced glucose intolerance and plasma insulin level, hepatic triglyceride content and adiposity in high-fat-fed mice without affecting caloric intake. This reduction in hepatosteatosis was attributed to suppressed lipid synthesis and increased fatty acid oxidation. In contrast to metformin, matrine neither suppressed mitochondrial respiration nor activated AMPK in the liver. A computational docking simulation revealed HSP90, a negative regulator of HSP72, as a potential binding target of matrine. Consistent with the simulation results, matrine, but not metformin, increased the hepatic protein level of HSP72 and this effect was inversely correlated with both liver triglyceride level and glucose intolerance. CONCLUSIONS AND IMPLICATIONS Taken together, these results indicate that matrine may be used for the treatment of type 2 diabetes and hepatic steatosis, and the molecular action of this hepatoprotective drug involves the activation of HSP72 in the liver.
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Affiliation(s)
- Xiao-Yi Zeng
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
| | - Hao Wang
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
| | - Fang Bai
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiu Zhou
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
| | - Song-Pei Li
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
| | - Lu-Ping Ren
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
| | - Ruo-Qiong Sun
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
| | - Charlie C L Xue
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
| | - Hua-Liang Jiang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Li-Hong Hu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ji-Ming Ye
- Lipid Biology and Metabolic Disease, Health Innovations Research Institute and School of Health Sciences, RMIT University, Melbourne, Vic, Australia
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48
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Berlanga A, Guiu-Jurado E, Porras JA, Aragonès G, Auguet T. [Role of metabolic lipases and lipotoxicity in the development of non-alcoholic steatosis and non-alcoholic steatohepatitis]. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS 2015; 28:47-61. [PMID: 26049666 DOI: 10.1016/j.arteri.2015.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 10/23/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in developed countries, covering a spectrum of pathological conditions ranging from single steatosis to non-alcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma. Its pathogenesis has been often interpreted by the "double-hit" hypothesis, where the lipid accumulation in the liver is followed by proinflammatory mediators inducing inflammation, hepatocellular injury and fibrosis. Nowadays, a more complex model suggests that free fatty acids and their metabolites could be the true lipotoxic agents that contribute to the development of NAFLD and hepatic insulin resistance, suggesting a central role for metabolic lipases in that process.
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Affiliation(s)
- Alba Berlanga
- Grupo de recerca GEMMAIR (AGAUR)-Medicina Aplicada, Departamento de Medicina y Cirugía, Universidad Rovira i Virgili (URV), Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, España
| | - Esther Guiu-Jurado
- Grupo de recerca GEMMAIR (AGAUR)-Medicina Aplicada, Departamento de Medicina y Cirugía, Universidad Rovira i Virgili (URV), Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, España
| | - José Antonio Porras
- Grupo de recerca GEMMAIR (AGAUR)-Medicina Aplicada, Departamento de Medicina y Cirugía, Universidad Rovira i Virgili (URV), Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, España; Servicio de Medicina Interna, Hospital Universitario Joan XXIII, Tarragona, España
| | - Gemma Aragonès
- Grupo de recerca GEMMAIR (AGAUR)-Medicina Aplicada, Departamento de Medicina y Cirugía, Universidad Rovira i Virgili (URV), Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, España
| | - Teresa Auguet
- Grupo de recerca GEMMAIR (AGAUR)-Medicina Aplicada, Departamento de Medicina y Cirugía, Universidad Rovira i Virgili (URV), Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, España; Servicio de Medicina Interna, Hospital Universitario Joan XXIII, Tarragona, España.
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49
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Obesity-related insulin resistance: implications for the surgical patient. Int J Obes (Lond) 2015; 39:1575-88. [PMID: 26028059 DOI: 10.1038/ijo.2015.100] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 05/17/2015] [Accepted: 05/24/2015] [Indexed: 12/20/2022]
Abstract
In healthy surgical patients, preoperative fasting and major surgery induce development of insulin resistance (IR). IR can be present in up to 41% of obese patients without diabetes and this can rise in the postoperative period, leading to an increased risk of postoperative complications. Inflammation is implicated in the aetiology of IR. This review examines obesity-associated IR and its implications for the surgical patient. Searches of the Medline and Science Citation Index databases were performed using various key words in combinations with the Boolean operators AND, OR and NOT. Key journals, nutrition and metabolism textbooks and the reference lists of key articles were also hand searched. Adipose tissue has been identified as an active endocrine organ and the chemokines secreted as a result of macrophage infiltration have a role in the pathogenesis of IR. Visceral adipose tissue appears to be the most metabolically active, although results across studies are not consistent. Results from animal and human studies often provide conflicting results, which has rendered the pursuit of a common mechanistic pathway challenging. Obesity-associated IR appears, in part, to be related to inflammatory changes associated with increased adiposity. Postoperatively, the surgical patient is in a proinflammatory state, so this finding has important implications for the obese surgical patient.
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50
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Tucci S, Flögel U, Spiekerkoetter U. Sexual dimorphism of lipid metabolism in very long-chain acyl-CoA dehydrogenase deficient (VLCAD-/-) mice in response to medium-chain triglycerides (MCT). Biochim Biophys Acta Mol Basis Dis 2015; 1852:1442-50. [PMID: 25887160 DOI: 10.1016/j.bbadis.2015.04.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/17/2015] [Accepted: 04/07/2015] [Indexed: 02/08/2023]
Abstract
Medium-chain triglycerides (MCT) are widely applied in the treatment of long-chain fatty acid oxidation disorders. Previously it was shown that long-term MCT supplementation strongly affects lipid metabolism in mice. We here investigate sex-specific effects in mice with very-long-chain-acyl-CoA dehydrogenase (VLCAD) deficiency in response to a long-term MCT modified diet. We quantified blood lipids, acylcarnitines, glucose, insulin and free fatty acids, as well as tissue triglycerides in the liver and skeletal muscle under a control and an MCT diet over 1 year. In addition, visceral and hepatic fat content and muscular intramyocellular lipids (IMCL) were assessed by in vivo(1)H magnetic resonance spectroscopy (MRS) techniques. The long-term application of an MCT diet induced a marked alteration of glucose homeostasis. However, only VLCAD-/- female mice developed a severe metabolic syndrome characterized by marked insulin resistance, dyslipidemia, severe hepatic and visceral steatosis, whereas VLCAD-/- males seemed to be protected and only presented with milder insulin resistance. Moreover, the highly saturated MCT diet is associated with a decreased hepatic stearoyl-CoA desaturase 1 (SCD1) activity in females aggravating the harmful effects of a saturated MCT diet. Long-term MCT supplementation deeply affects lipid metabolism in a sexual dimorphic manner resulting in a severe metabolic syndrome only in female mice. These findings are striking since the first signs of insulin resistance already occur in female VLCAD-/- mice during their reproductive period. How these metabolic adaptations are finally regulated needs to be determined. More important, the relevance of these findings for humans under these dietary modifications needs to be investigated.
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Affiliation(s)
- Sara Tucci
- Department of General Pediatrics, Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, 79106 Freiburg, Germany.
| | - Ulrich Flögel
- Department of Molecular Cardiology, Heinrich-Heine-University Duesseldorf, 40225 Düsseldorf, Germany
| | - Ute Spiekerkoetter
- Department of General Pediatrics, Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, 79106 Freiburg, Germany
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