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Oligostilbenes from the seeds of Paeonia lactiflora as potent GLP-1 secretagogues targeting TGR5 receptor. Fitoterapia 2022; 163:105336. [DOI: 10.1016/j.fitote.2022.105336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/12/2022] [Accepted: 10/12/2022] [Indexed: 11/21/2022]
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2
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Sharma AK, Singh S, Singh H, Mahajan D, Kolli P, Mandadapu G, Kumar B, Kumar D, Kumar S, Jena MK. Deep Insight of the Pathophysiology of Gestational Diabetes Mellitus. Cells 2022; 11:2672. [PMID: 36078079 PMCID: PMC9455072 DOI: 10.3390/cells11172672] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 12/19/2022] Open
Abstract
Diabetes mellitus is a severe metabolic disorder, which consistently requires medical care and self-management to restrict complications, such as obesity, kidney damage and cardiovascular diseases. The subtype gestational diabetes mellitus (GDM) occurs during pregnancy, which severely affects both the mother and the growing foetus. Obesity, uncontrolled weight gain and advanced gestational age are the prominent risk factors for GDM, which lead to high rate of perinatal mortality and morbidity. In-depth understanding of the molecular mechanism involved in GDM will help researchers to design drugs for the optimal management of the condition without affecting the mother and foetus. This review article is focused on the molecular mechanism involved in the pathophysiology of GDM and the probable biomarkers, which can be helpful for the early diagnosis of the condition. The early diagnosis of the metabolic disorder, most preferably in first trimester of pregnancy, will lead to its effective long-term management, reducing foetal developmental complications and mortality along with safety measures for the mother.
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Affiliation(s)
- Amarish Kumar Sharma
- Department of Biotechnology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, Punjab, India
| | - Sanjeev Singh
- Department of Biotechnology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, Punjab, India
| | - Himanshu Singh
- Department of Biotechnology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, Punjab, India
| | - Deviyani Mahajan
- Department of Biotechnology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, Punjab, India
| | - Prachetha Kolli
- Microgen Health Inc., 14225 Sullyfield Cir Suite E, Chantilly, VA 20151, USA
| | | | - Bimlesh Kumar
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, Punjab, India
| | - Dharmendra Kumar
- Animal Physiology and Reproduction Division, ICAR-Central Institute for Research on Buffaloes, Hisar 125001, Haryana, India
| | - Sudarshan Kumar
- Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal 132001, Haryana, India
| | - Manoj Kumar Jena
- Department of Biotechnology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, Punjab, India
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3
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Wang W, Zhang C. Targeting β-cell dedifferentiation and transdifferentiation: opportunities and challenges. Endocr Connect 2021; 10:R213-R228. [PMID: 34289444 PMCID: PMC8428079 DOI: 10.1530/ec-21-0260] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/21/2021] [Indexed: 12/02/2022]
Abstract
The most distinctive pathological characteristics of diabetes mellitus induced by various stressors or immune-mediated injuries are reductions of pancreatic islet β-cell populations and activity. Existing treatment strategies cannot slow disease progression; consequently, research to genetically engineer β-cell mimetics through bi-directional plasticity is ongoing. The current consensus implicates β-cell dedifferentiation as the primary etiology of reduced β-cell mass and activity. This review aims to summarize the etiology and proposed mechanisms of β-cell dedifferentiation and to explore the possibility that there might be a time interval from the onset of β-cell dysfunction caused by dedifferentiation to the development of diabetes, which may offer a therapeutic window to reduce β-cell injury and to stabilize functionality. In addition, to investigate β-cell plasticity, we review strategies for β-cell regeneration utilizing genetic programming, small molecules, cytokines, and bioengineering to transdifferentiate other cell types into β-cells; the development of biomimetic acellular constructs to generate fully functional β-cell-mimetics. However, the maturation of regenerated β-cells is currently limited. Further studies are needed to develop simple and efficient reprogramming methods for assembling perfectly functional β-cells. Future investigations are necessary to transform diabetes into a potentially curable disease.
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Affiliation(s)
- Wenrui Wang
- Department of Endocrinology, The Second Hospital of Jilin University, Changchun, People’s Republic of China
| | - Chuan Zhang
- Department of Endocrinology, The Second Hospital of Jilin University, Changchun, People’s Republic of China
- Correspondence should be addressed to C Zhang:
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4
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Mitochondrial Carriers Regulating Insulin Secretion Profiled in Human Islets upon Metabolic Stress. Biomolecules 2020; 10:biom10111543. [PMID: 33198243 PMCID: PMC7697104 DOI: 10.3390/biom10111543] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 11/10/2020] [Indexed: 12/27/2022] Open
Abstract
Chronic exposure of β-cells to nutrient-rich metabolic stress impairs mitochondrial metabolism and its coupling to insulin secretion. We exposed isolated human islets to different metabolic stresses for 3 days: 0.4 mM oleate or 0.4 mM palmitate at physiological 5.5 mM glucose (lipotoxicity), high 25 mM glucose (glucotoxicity), and high 25 mM glucose combined with 0.4 mM oleate and/or palmitate (glucolipotoxicity). Then, we profiled the mitochondrial carriers and associated genes with RNA-Seq. Diabetogenic conditions, and in particular glucotoxicity, increased expression of several mitochondrial solute carriers in human islets, such as the malate carrier DIC, the α-ketoglutarate-malate exchanger OGC, and the glutamate carrier GC1. Glucotoxicity also induced a general upregulation of the electron transport chain machinery, while palmitate largely counteracted this effect. Expression of different components of the TOM/TIM mitochondrial protein import system was increased by glucotoxicity, whereas glucolipotoxicity strongly upregulated its receptor subunit TOM70. Expression of the mitochondrial calcium uniporter MCU was essentially preserved by metabolic stresses. However, glucotoxicity altered expression of regulatory elements of calcium influx as well as the Na+/Ca2+ exchanger NCLX, which mediates calcium efflux. Overall, the expression profile of mitochondrial carriers and associated genes was modified by the different metabolic stresses exhibiting nutrient-specific signatures.
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Zhang H, Wang Q, He S, Wu K, Ren M, Dong H, Di J, Yu Z, Huang C. Ambient air pollution and gestational diabetes mellitus: A review of evidence from biological mechanisms to population epidemiology. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 719:137349. [PMID: 32114225 DOI: 10.1016/j.scitotenv.2020.137349] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/06/2020] [Accepted: 02/14/2020] [Indexed: 05/26/2023]
Abstract
Gestational diabetes mellitus (GDM) is a serious complication of pregnancy that could cause adverse health effects on both mothers and fetuses, and its prevalence has been increasing worldwide. Experimental and epidemiological studies suggest that air pollution may be an important risk factor of GDM, but conclusions are inconsistent. To provide a comprehensive overview of ambient air pollution on GDM, we summarized existing evidence concerning biological linkages between maternal exposure to air pollutants and GDM based on mechanism studies. We also performed a quantitative meta-analysis based on human epidemiological studies by searching English databases (Pubmed, Web of Science and Embase) and Chinese databases (Wanfang, CNKI). As a result, the limited mechanism studies indicated that β-cell dysfunction, neurohormonal disturbance, inflammation, oxidative stress, imbalance of gut microbiome and insulin resistance may be involved in air pollution-GDM relationship, but few studies were performed to explore the direct biological linkage. Additionally, a total of 13 epidemiological studies were included in the meta-analysis, and the air pollutants considered included PM2.5, PM10, SO2, NO2 and O3. Most studies were retrospective and mainly conducted in developed regions. The results of meta-analysis indicated that maternal first trimester exposure to SO2 increased the risk of GDM (standardized odds ratio (OR) = 1.392, 95% confidence intervals (CI): 1.010, 1.773), while pre-pregnancy O3 exposure was inversely associated with GDM risk (standardized OR = 0.981, 95% CI: 0.977, 0.985). No significant effects were observed for PM2.5, PM10 and NO2. In conclusion, additional mechanism studies on the molecular level are needed to provide persuasive rationale underlying the air pollution-GDM relationship. Moreover, other important risk factors of GDM, including maternal lifestyle and road traffic noise exposure that may modify the air pollution-GDM relationship should be considered in future epidemiological studies. More prospective cohort studies are also warranted in developing countries with high levels of air pollution.
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Affiliation(s)
- Huanhuan Zhang
- School of Public Health, Zhengzhou University, Zhengzhou 450001, China; School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Qiong Wang
- School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Simin He
- School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Kaipu Wu
- School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Meng Ren
- School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Haotian Dong
- School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Jiangli Di
- National Center for Women and Children's Health, Chinese Center for Disease Control and Prevention, Beijing, China.
| | - Zengli Yu
- School of Public Health, Zhengzhou University, Zhengzhou 450001, China.
| | - Cunrui Huang
- School of Public Health, Zhengzhou University, Zhengzhou 450001, China; School of Public Health, Sun Yat-sen University, Guangzhou 510080, China; Shanghai Typhoon Institute, China Meteorological Administration, Shanghai 200030, China; Shanghai Key Laboratory of Meteorology and Health, Shanghai Meteorological Service, Shanghai 200030, China.
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6
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Prentki M, Peyot ML, Masiello P, Madiraju SRM. Nutrient-Induced Metabolic Stress, Adaptation, Detoxification, and Toxicity in the Pancreatic β-Cell. Diabetes 2020; 69:279-290. [PMID: 32079704 DOI: 10.2337/dbi19-0014] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/20/2019] [Indexed: 11/13/2022]
Abstract
Paraphrasing the Swiss physician and father of toxicology Paracelsus (1493-1541) on chemical agents used as therapeutics, "the dose makes the poison," it is now realized that this aptly applies to the calorigenic nutrients. The case here is the pancreatic islet β-cell presented with excessive levels of nutrients such as glucose, lipids, and amino acids. The short-term effects these nutrients exert on the β-cell are enhanced insulin biosynthesis and secretion and changes in glucose sensitivity. However, chronic fuel surfeit triggers additional compensatory and adaptive mechanisms by β-cells to cope with the increased insulin demand or to protect itself. When these mechanisms fail, toxicity due to the nutrient surplus ensues, leading to β-cell dysfunction, dedifferentiation, and apoptosis. The terms glucotoxicity, lipotoxicity, and glucolipotoxicity have been widely used, but there is some confusion as to what they mean precisely and which is most appropriate for a given situation. Here we address the gluco-, lipo-, and glucolipo-toxicities in β-cells by assessing the evidence both for and against each of them. We also discuss potential mechanisms and defend the view that many of the identified "toxic" effects of nutrient excess, which may also include amino acids, are in fact beneficial adaptive processes. In addition, candidate fuel-excess detoxification pathways are evaluated. Finally, we propose that a more general term should be used for the in vivo situation of overweight-associated type 2 diabetes reflecting both the adaptive and toxic processes to mixed calorigenic nutrients excess: "nutrient-induced metabolic stress" or, in brief, "nutri-stress."
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Affiliation(s)
- Marc Prentki
- Departments of Nutrition and Biochemistry and Molecular Medicine, University of Montreal, and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Quebec, Canada
| | - Marie-Line Peyot
- Departments of Nutrition and Biochemistry and Molecular Medicine, University of Montreal, and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Quebec, Canada
| | - Pellegrino Masiello
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - S R Murthy Madiraju
- Departments of Nutrition and Biochemistry and Molecular Medicine, University of Montreal, and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Quebec, Canada
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7
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Plows JF, Stanley JL, Baker PN, Reynolds CM, Vickers MH. The Pathophysiology of Gestational Diabetes Mellitus. Int J Mol Sci 2018; 19:E3342. [PMID: 30373146 PMCID: PMC6274679 DOI: 10.3390/ijms19113342] [Citation(s) in RCA: 825] [Impact Index Per Article: 137.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/15/2018] [Accepted: 10/21/2018] [Indexed: 12/11/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is a serious pregnancy complication, in which women without previously diagnosed diabetes develop chronic hyperglycemia during gestation. In most cases, this hyperglycemia is the result of impaired glucose tolerance due to pancreatic β-cell dysfunction on a background of chronic insulin resistance. Risk factors for GDM include overweight and obesity, advanced maternal age, and a family history or any form of diabetes. Consequences of GDM include increased risk of maternal cardiovascular disease and type 2 diabetes and macrosomia and birth complications in the infant. There is also a longer-term risk of obesity, type 2 diabetes, and cardiovascular disease in the child. GDM affects approximately 16.5% of pregnancies worldwide, and this number is set to increase with the escalating obesity epidemic. While several management strategies exist-including insulin and lifestyle interventions-there is not yet a cure or an efficacious prevention strategy. One reason for this is that the molecular mechanisms underlying GDM are poorly defined. This review discusses what is known about the pathophysiology of GDM, and where there are gaps in the literature that warrant further exploration.
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Affiliation(s)
- Jasmine F Plows
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA 90033, USA.
| | - Joanna L Stanley
- Liggins Institute, University of Auckland, Auckland 1023, New Zealand.
| | - Philip N Baker
- University of Leicester, University Road, Leicester LE1 7RH, UK.
| | - Clare M Reynolds
- Liggins Institute, University of Auckland, Auckland 1023, New Zealand.
| | - Mark H Vickers
- Liggins Institute, University of Auckland, Auckland 1023, New Zealand.
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8
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van Krieken PP, Dicker A, Eriksson M, Herrera PL, Ahlgren U, Berggren PO, Ilegems E. Kinetics of functional beta cell mass decay in a diphtheria toxin receptor mouse model of diabetes. Sci Rep 2017; 7:12440. [PMID: 28963457 PMCID: PMC5622115 DOI: 10.1038/s41598-017-12124-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/04/2017] [Indexed: 11/26/2022] Open
Abstract
Functional beta cell mass is an essential biomarker for the diagnosis and staging of diabetes. It has however proven technically challenging to study this parameter during diabetes progression. Here we have detailed the kinetics of the rapid decline in functional beta cell mass in the RIP-DTR mouse, a model of hyperglycemia resulting from diphtheria toxin induced beta cell ablation. A novel combination of imaging modalities was employed to study the pattern of beta cell destruction. Optical projection tomography of the pancreas and longitudinal in vivo confocal microscopy of islets transplanted into the anterior chamber of the eye allowed to investigate kinetics and tomographic location of beta cell mass decay in individual islets as well as at the entire islet population level. The correlation between beta cell mass and function was determined by complementary in vivo and ex vivo characterizations, demonstrating that beta cell function and glucose tolerance were impaired within the first two days following treatment when more than 50% of beta cell mass was remaining. Our results illustrate the importance of acquiring quantitative functional and morphological parameters to assess the functional status of the endocrine pancreas.
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Affiliation(s)
- Pim P van Krieken
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Andrea Dicker
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Maria Eriksson
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Pedro L Herrera
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Ulf Ahlgren
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden. .,Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, USA. .,Lee Kong Chian School of Medicine, Nanyang Technological University, Imperial College London, Novena Campus, Singapore, Singapore.
| | - Erwin Ilegems
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
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9
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Dumortier O, Fabris G, Van Obberghen E. Shaping and preserving β-cell identity with microRNAs. Diabetes Obes Metab 2016; 18 Suppl 1:51-7. [PMID: 27615131 DOI: 10.1111/dom.12722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/26/2016] [Indexed: 12/18/2022]
Abstract
The highly sophisticated identity of pancreatic β-cells is geared to accomplish its unique feat of providing insulin for organismal glucose and lipid homeostasis. This requires a particular and streamlined fuel metabolism which defines mature β-cells as glucose sensors linked to an insulin exocytosis machinery. The establishment of an appropriate β-cell mass and function during development as well as the maintenance of their identity throughout life are necessary for energy homeostasis. The small non-coding RNAs, microRNAs (miRNAs), are now well-recognized regulators of gene transcripts, which in general are negatively affected by them. Convincing evidence exists to view miRNAs as major actors in β-cell development and function, suggesting an important role for them in the distinctive β-cell 'identity card'. Here, we summarize key features that associate miRNAs and the establishment of the appropriate β-cell identity and its necessary maintenance during their 'long life'.
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Affiliation(s)
- O Dumortier
- University Côte d'Azur, Inserm, CNRS, IRCAN, France
| | - G Fabris
- University Côte d'Azur, Inserm, CNRS, IRCAN, France
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10
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Wortham M, Sander M. Mechanisms of β-cell functional adaptation to changes in workload. Diabetes Obes Metab 2016; 18 Suppl 1:78-86. [PMID: 27615135 PMCID: PMC5021190 DOI: 10.1111/dom.12729] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/09/2016] [Indexed: 11/28/2022]
Abstract
Insulin secretion must be tightly coupled to nutritional state to maintain blood glucose homeostasis. To this end, pancreatic β-cells sense and respond to changes in metabolic conditions, thereby anticipating insulin demands for a given physiological context. This is achieved in part through adjustments of nutrient metabolism, which is controlled at several levels including allosteric regulation, post-translational modifications, and altered expression of metabolic enzymes. In this review, we discuss mechanisms of β-cell metabolic and functional adaptation in the context of two physiological states that alter glucose-stimulated insulin secretion: fasting and insulin resistance. We review current knowledge of metabolic changes that occur in the β-cell during adaptation and specifically discuss transcriptional mechanisms that underlie β-cell adaptation. A more comprehensive understanding of how β-cells adapt to changes in nutrient state could identify mechanisms to be co-opted for therapeutically modulating insulin secretion in metabolic disease.
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Affiliation(s)
- M Wortham
- Departments of Pediatrics and Cellular and Molecular Medicine, Pediatric Diabetes Research Center, University of California San Diego, La Jolla
| | - M Sander
- Departments of Pediatrics and Cellular and Molecular Medicine, Pediatric Diabetes Research Center, University of California San Diego, La Jolla.
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11
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Kim-Muller JY, Kim YJR, Fan J, Zhao S, Banks AS, Prentki M, Accili D. FoxO1 Deacetylation Decreases Fatty Acid Oxidation in β-Cells and Sustains Insulin Secretion in Diabetes. J Biol Chem 2016; 291:10162-72. [PMID: 26984405 DOI: 10.1074/jbc.m115.705608] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Indexed: 11/06/2022] Open
Abstract
Pancreatic β-cell dysfunction contributes to onset and progression of type 2 diabetes. In this state β-cells become metabolically inflexible, losing the ability to select between carbohydrates and lipids as substrates for mitochondrial oxidation. These changes lead to β-cell dedifferentiation. We have proposed that FoxO proteins are activated through deacetylation-dependent nuclear translocation to forestall the progression of these abnormalities. However, how deacetylated FoxO exert their actions remains unclear. To address this question, we analyzed islet function in mice homozygous for knock-in alleles encoding deacetylated FoxO1 (6KR). Islets expressing 6KR mutant FoxO1 have enhanced insulin secretion in vivo and ex vivo and decreased fatty acid oxidation ex vivo Remarkably, the gene expression signature associated with FoxO1 deacetylation differs from wild type by only ∼2% of the >4000 genes regulated in response to re-feeding. But this narrow swath includes key genes required for β-cell identity, lipid metabolism, and mitochondrial fatty acid and solute transport. The data support the notion that deacetylated FoxO1 protects β-cell function by limiting mitochondrial lipid utilization and raise the possibility that inhibition of fatty acid oxidation in β-cells is beneficial to diabetes treatment.
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Affiliation(s)
- Ja Young Kim-Muller
- From the Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, New York 10032, Merck Research Laboratories, Boston, Massachusetts 02816
| | - Young Jung R Kim
- From the Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, New York 10032
| | - Jason Fan
- From the Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, New York 10032
| | - Shangang Zhao
- Molecular Nutrition Unit and Montreal Diabetes Research Center at the CRCHUM and Departments of Nutrition and Biochemistry and Department of Molecular Medicine, Université de Montréal, Montréal, H2X 0A9, Canada, and
| | | | - Marc Prentki
- Molecular Nutrition Unit and Montreal Diabetes Research Center at the CRCHUM and Departments of Nutrition and Biochemistry and Department of Molecular Medicine, Université de Montréal, Montréal, H2X 0A9, Canada, and
| | - Domenico Accili
- From the Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, New York 10032,
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12
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Identification of a mammalian glycerol-3-phosphate phosphatase: Role in metabolism and signaling in pancreatic β-cells and hepatocytes. Proc Natl Acad Sci U S A 2016; 113:E430-9. [PMID: 26755581 DOI: 10.1073/pnas.1514375113] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Obesity, and the associated disturbed glycerolipid/fatty acid (GL/FA) cycle, contribute to insulin resistance, islet β-cell failure, and type 2 diabetes. Flux through the GL/FA cycle is regulated by the availability of glycerol-3-phosphate (Gro3P) and fatty acyl-CoA. We describe here a mammalian Gro3P phosphatase (G3PP), which was not known to exist in mammalian cells, that can directly hydrolyze Gro3P to glycerol. We identified that mammalian phosphoglycolate phosphatase, with an uncertain function, acts in fact as a G3PP. We found that G3PP, by controlling Gro3P levels, regulates glycolysis and glucose oxidation, cellular redox and ATP production, gluconeogenesis, glycerolipid synthesis, and fatty acid oxidation in pancreatic islet β-cells and hepatocytes, and that glucose stimulated insulin secretion and the response to metabolic stress, e.g., glucolipotoxicity, in β-cells. In vivo overexpression of G3PP in rat liver lowers body weight gain and hepatic glucose production from glycerol and elevates plasma HDL levels. G3PP is expressed at various levels in different tissues, and its expression varies according to the nutritional state in some tissues. As Gro3P lies at the crossroads of glucose, lipid, and energy metabolism, control of its availability by G3PP adds a key level of metabolic regulation in mammalian cells, and G3PP offers a potential target for type 2 diabetes and cardiometabolic disorders.
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13
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Kim-Muller JY, Zhao S, Srivastava S, Mugabo Y, Noh HL, Kim YR, Madiraju SRM, Ferrante AW, Skolnik EY, Prentki M, Accili D. Metabolic inflexibility impairs insulin secretion and results in MODY-like diabetes in triple FoxO-deficient mice. Cell Metab 2014; 20:593-602. [PMID: 25264246 PMCID: PMC4192072 DOI: 10.1016/j.cmet.2014.08.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 06/25/2014] [Accepted: 08/22/2014] [Indexed: 12/17/2022]
Abstract
Pancreatic β cell failure in type 2 diabetes is associated with functional abnormalities of insulin secretion and deficits of β cell mass. It's unclear how one begets the other. We have shown that loss of β cell mass can be ascribed to impaired FoxO1 function in different models of diabetes. Here we show that ablation of the three FoxO genes (1, 3a, and 4) in mature β cells results in early-onset, maturity-onset diabetes of the young (MODY)-like diabetes, with abnormalities of the MODY networks Hnf4α, Hnf1α, and Pdx1. FoxO-deficient β cells are metabolically inflexible, i.e., they preferentially utilize lipids rather than carbohydrates as an energy source. This results in impaired ATP generation and reduced Ca(2+)-dependent insulin secretion. The present findings demonstrate a secretory defect caused by impaired FoxO activity that antedates dedifferentiation. We propose that defects in both pancreatic β cell function and mass arise through FoxO-dependent mechanisms during diabetes progression.
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Affiliation(s)
- Ja Young Kim-Muller
- Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Shangang Zhao
- Molecular Nutrition Unit and Montreal Diabetes Research Center at the CRCHUM and Departments of Nutrition and Biochemistry, and Molecular Medicine, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | - Shekhar Srivastava
- Division of Nephrology, The Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute for Biomolecular Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Yves Mugabo
- Molecular Nutrition Unit and Montreal Diabetes Research Center at the CRCHUM and Departments of Nutrition and Biochemistry, and Molecular Medicine, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | - Hye-Lim Noh
- Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, NY 10032, USA
| | - YoungJung R Kim
- Department of Genetics and Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University, New York, NY 10032, USA
| | - S R Murthy Madiraju
- Molecular Nutrition Unit and Montreal Diabetes Research Center at the CRCHUM and Departments of Nutrition and Biochemistry, and Molecular Medicine, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | - Anthony W Ferrante
- Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Edward Y Skolnik
- Division of Nephrology, The Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute for Biomolecular Medicine, New York University Langone Medical Center, New York, NY 10016, USA
| | - Marc Prentki
- Molecular Nutrition Unit and Montreal Diabetes Research Center at the CRCHUM and Departments of Nutrition and Biochemistry, and Molecular Medicine, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | - Domenico Accili
- Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, NY 10032, USA.
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14
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Abstract
Free fatty acids (FFAs) exert both positive and negative effects on beta cell survival and insulin secretory function, depending on concentration, duration, and glucose abundance. Lipid signals are mediated not only through metabolic pathways, but also through cell surface and nuclear receptors. Toxicity is modulated by positive signals arising from circulating factors such as hormones, growth factors and incretins, as well as negative signals such as inflammatory mediators and cytokines. Intracellular mechanisms of lipotoxicity include metabolic interference and cellular stress responses such as oxidative stress, endoplasmic reticulum (ER) stress, and possibly autophagy. New findings strengthen an old hypothesis that lipids may also impair compensatory beta cell proliferation. Clinical observations continue to support a role for lipid biology in the risk and progression of both type 1 (T1D) and type 2 diabetes (T2D). This review summarizes recent work in this important, rapidly evolving field.
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Affiliation(s)
- Rohit B Sharma
- Diabetes Center of Excellence, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
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15
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Yang S, Xia C, Li S, Du L, Zhang L, Zhou R. Defective mitophagy driven by dysregulation of rheb and KIF5B contributes to mitochondrial reactive oxygen species (ROS)-induced nod-like receptor 3 (NLRP3) dependent proinflammatory response and aggravates lipotoxicity. Redox Biol 2014; 3:63-71. [PMID: 25462067 PMCID: PMC4295565 DOI: 10.1016/j.redox.2014.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 04/05/2014] [Accepted: 04/07/2014] [Indexed: 01/07/2023] Open
Abstract
High-fat diet (HFD) and inflammation are the key
contributors to insulin resistance and type 2 diabetes (T2D). Previous study
shows fatty acid-induced accumulation of damaged, reactive oxygen species
(ROS)-generating mitochondria, and this in turn activates the NLRP3 inflammasome
interference with insulin signaling. Our previous research shows NLRP3
inflammasome activation signal originates from defects in autophagy. Yet how the
fatty acid related to mitophagy alteration leads to the activation of NLRP3-ASC
inflammasome has not been considered. Here we demonstrated that palmitate (PA)
induced mitophagy deficiency, leading to damaged mitochondrion as characterized
by mito-ROS production and loss of membrane potential. Antioxidant APDC or
Ca2+ signaling inhibitor Nifedipine blocked PA-induced
NLRP3 inflammasome activation. Further, we provided evidences that PA reduced
the expression of Ras homolog enriched in brain (Rheb) and disrupted Rheb
recruitment to the mitochondrial outer membrane. In addition, sustained PA
caused disassociation of kinesin family member 5B (KIF5B) from binding with
mitochondria via Ca2+-dependent effects. Disruption of Rheb and
KIF5B interaction with mitochondria blocked mitochondrial degradation along with
IL-1β dependent insulin resistance, which was majorly attenuated by Rheb/KIF5B
overexpression. In a consequence, defective mitophagy led to the accumulation of
damaged-ROS-generating mitochondria, down pathway of NLRP3-ASC-Caspase 1
activation, and subsequently, insulin resistance. These findings provide
insights into the association of inflammation, mitophagy and
T2D. PA induced disruption of KIF5B-mediated mitochondrial
motility and loss of Rheb-dependent mitophagy. Defective mitophagy led to NLRP3-ASC-Caspase 1
activation, and subsequently, insulin resistance. Antioxidant APDC or Ca2+ signaling
inhibitor nifidipine blocked PA-induced NLRP3 inflammasome
activation.
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Affiliation(s)
- Sijun Yang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu Province 210046, China.
| | - Chunxiang Xia
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu Province 210046, China
| | - Shali Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu Province 210046, China
| | - Leilei Du
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu Province 210046, China
| | - Lu Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu Province 210046, China
| | - Ronbin Zhou
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing, Jiangsu Province 210046, China
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16
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Kurohane Kaneko Y, Kobayashi Y, Motoki K, Nakata K, Miyagawa S, Yamamoto M, Hayashi D, Shirai Y, Sakane F, Ishikawa T. Depression of type I diacylglycerol kinases in pancreatic β-cells from male mice results in impaired insulin secretion. Endocrinology 2013; 154:4089-98. [PMID: 24035999 DOI: 10.1210/en.2013-1356] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Diacylglycerol kinase (DGK) catalyzes the conversion of diacylglycerol (DAG) to phosphatidic acid. This study investigated the expression and function of DGK in pancreatic β-cells. mRNA expression of type I DGK isoforms (α, β, γ) was detected in mouse pancreatic islets and the β-cell line MIN6. Protein expression of DGKα and DGKγ was also detected in mouse β-cells and MIN6 cells. The type I DGK inhibitor R59949 inhibited high K(+)- and glucose-induced insulin secretion in MIN6 cells. Moreover, single knockdown of DGKα or DGKγ by small interfering RNA slightly but significantly decreased glucose- and high K(+)-induced insulin secretions, and the double knockdown further decreased them to the levels comparable with those induced by R59949. R59949 and DiC8, a membrane permeable DAG analog, decreased intracellular Ca(2+) concentration elevated by glucose and high K(+) in MIN6 cells. Real-time imaging in MIN6 cells expressing green fluorescent protein-tagged DGKα or DGKγ showed that the DGK activator phorbol 12-myristate 13-acetate rapidly induced translocation of DGKγ to the plasma membrane, whereas high K(+) slowly translocated DGKα and DGKγ to the plasma membrane. R59949 increased the DAG content in MIN6 cells when stimulated with high KCl, whereas it did not increase the DAG content but decreased the phosphatidic acid content when stimulated with high glucose. Finally, R59949 was confirmed to inhibit high K(+)-induced insulin secretion from mouse islets and glucose-induced insulin secretion from rat islets. These results suggest that DGKα and DGKγ are present in β-cells and that the depression of these DGKs causes a decrease in intracellular Ca(2+) concentration, thereby reducing insulin secretion.
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Guo L, Inada A, Aguayo-Mazzucato C, Hollister-Lock J, Fujitani Y, Weir GC, Wright CV, Sharma A, Bonner-Weir S. PDX1 in ducts is not required for postnatal formation of β-cells but is necessary for their subsequent maturation. Diabetes 2013; 62:3459-68. [PMID: 23775765 PMCID: PMC3781453 DOI: 10.2337/db12-1833] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Pancreatic duodenal homeobox-1 (Pdx1), a transcription factor required for pancreatic development and maintenance of β-cell function, was assessed for a possible role in postnatal β-cell formation from progenitors in the pancreatic ducts by selectively deleting Pdx1 from the ducts. Carbonic anhydrase II (CAII)(Cre);Pdx1(Fl) mice were euglycemic for the first 2 postnatal weeks but showed moderate hyperglycemia from 3 to 7 weeks of age. By 10 weeks, they had near-normal morning fed glucose levels but showed severely impaired glucose tolerance and insulin secretion. Yet the loss of Pdx1 did not result in decreased islet and β-cell mass at 4 and 10 weeks of age. Within the same pancreas, there was a mixed population of islets, with PDX1 and MAFA protein expression normal in some cells and severely diminished in others. Even at 10 weeks, islets expressed immaturity markers. Thus, we conclude that Pdx1 is not necessary for the postnatal formation of β-cells but is essential for their full maturation to glucose-responsive β-cells.
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Affiliation(s)
- Lili Guo
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Akari Inada
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
- Diabetes and Genes, Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Cristina Aguayo-Mazzucato
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Jennifer Hollister-Lock
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Yoshio Fujitani
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Gordon C. Weir
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Christopher V.E. Wright
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Arun Sharma
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Susan Bonner-Weir
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
- Corresponding author: Susan Bonner-Weir,
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18
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Abstract
The pancreatic islet β cell senses circulating levels of calorigenic nutrients to secrete insulin according to the needs of the organism. Altered insulin secretion is linked to various disorders such as diabetes, hypoglycemic states, and cardiometabolic diseases. Fuel stimuli, including glucose, free fatty acids, and amino acids, promote insulin granule exocytosis primarily via their metabolism in β cells and the production of key signaling metabolites. This paper reviews our current knowledge of the pathways involved in both positive and negative metabolic signaling for insulin secretion and assesses the role of established and candidate metabolic coupling factors, keeping recent developments in focus.
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Affiliation(s)
- Marc Prentki
- Molecular Nutrition Unit, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, QC, Canada.
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19
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Gupta D, Leahy AA, Monga N, Peshavaria M, Jetton TL, Leahy JL. Peroxisome proliferator-activated receptor γ (PPARγ) and its target genes are downstream effectors of FoxO1 protein in islet β-cells: mechanism of β-cell compensation and failure. J Biol Chem 2013; 288:25440-25449. [PMID: 23788637 DOI: 10.1074/jbc.m113.486852] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The molecular mechanisms and signaling pathways that drive islet β-cell compensation and failure are not fully resolved. We have used in vitro and in vivo systems to show that FoxO1, an integrator of metabolic stimuli, inhibits PPARγ expression in β-cells, thus transcription of its target genes (Pdx1, glucose-dependent insulinotropic polypeptide (GIP) receptor, and pyruvate carboxylase) that are important regulators of β-cell function, survival, and compensation. FoxO1 inhibition of target gene transcription is normally relieved when upstream activation induces its translocation from the nucleus to the cytoplasm. Attesting to the central importance of this pathway, islet expression of PPARγ and its target genes was enhanced in nondiabetic insulin-resistant rats and markedly reduced with diabetes induction. Insight into the impaired PPARγ signaling with hyperglycemia was obtained with confocal microscopy of pancreas sections that showed an intense nuclear FoxO1 immunostaining pattern in the β-cells of diabetic rats in contrast to the nuclear and cytoplasmic FoxO1 in nondiabetic rats. These findings suggest a FoxO1/PPARγ-mediated network acting as a core component of β-cell adaptation to metabolic stress, with failure of this response from impaired FoxO1 activation causing or exacerbating diabetes.
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Affiliation(s)
- Dhananjay Gupta
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Averi A Leahy
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Navjot Monga
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Mina Peshavaria
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Thomas L Jetton
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Jack L Leahy
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont 05405.
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20
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Weir GC, Bonner-Weir S. Islet β cell mass in diabetes and how it relates to function, birth, and death. Ann N Y Acad Sci 2013; 1281:92-105. [PMID: 23363033 PMCID: PMC3618572 DOI: 10.1111/nyas.12031] [Citation(s) in RCA: 237] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In type 1 diabetes (T1D) β cell mass is markedly reduced by autoimmunity. Type 2 diabetes (T2D) results from inadequate β cell mass and function that can no longer compensate for insulin resistance. The reduction of β cell mass in T2D may result from increased cell death and/or inadequate birth through replication and neogenesis. Reduction in mass allows glucose levels to rise, which places β cells in an unfamiliar hyperglycemic environment, leading to marked changes in their phenotype and a dramatic loss of glucose-stimulated insulin secretion (GSIS), which worsens as glucose levels climb. Toxic effects of glucose on β cells (glucotoxicity) appear to be the culprit. This dysfunctional insulin secretion can be reversed when glucose levels are lowered by treatment, a finding with therapeutic significance. Restoration of β cell mass in both types of diabetes could be accomplished by either β cell regeneration or transplantation. Learning more about the relationships between β cell mass, turnover, and function and finding ways to restore β cell mass are among the most urgent priorities for diabetes research.
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Affiliation(s)
- Gordon C Weir
- Section on Islet Cell Biology and Regenerative Medicine, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, MA 02215, USA.
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21
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Vernier S, Chiu A, Schober J, Weber T, Nguyen P, Luer M, McPherson T, Wanda PE, Marshall CA, Rohatgi N, McDaniel ML, Greenberg AS, Kwon G. β-cell metabolic alterations under chronic nutrient overload in rat and human islets. Islets 2012; 4:379-92. [PMID: 23247575 PMCID: PMC3605166 DOI: 10.4161/isl.22720] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The aim of this study was to assess multifactorial β-cell responses to metabolic perturbations in primary rat and human islets. Treatment of dispersed rat islet cells with elevated glucose and free fatty acids (FFAs, oleate:palmitate = 1:1 v/v) resulted in increases in the size and the number of lipid droplets in β-cells in a time- and concentration-dependent manner. Glucose and FFAs synergistically stimulated the nutrient sensor mammalian target of rapamycin complex 1 (mTORC1). A potent mTORC1 inhibitor, rapamycin (25 nM), significantly reduced triglyceride accumulation in rat islets. Importantly, lipid droplets accumulated only in β-cells but not in α-cells in an mTORC1-dependent manner. Nutrient activation of mTORC1 upregulated the expression of adipose differentiation related protein (ADRP), known to stabilize lipid droplets. Rat islet size and new DNA synthesis also increased under nutrient overload. Insulin secretion into the culture medium increased steadily over a 4-day period without any significant difference between glucose (10 mM) alone and the combination of glucose (10 mM) and FFAs (240 μM). Insulin content and insulin biosynthesis, however, were significantly reduced under the combination of nutrients compared with glucose alone. Elevated nutrients also stimulated lipid droplet formation in human islets in an mTORC1-dependent manner. Unlike rat islets, however, human islets did not increase in size under nutrient overload despite a normal response to nutrients in releasing insulin. The different responses of islet cell growth under nutrient overload appear to impact insulin biosynthesis and storage differently in rat and human islets.
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Affiliation(s)
- Stephanie Vernier
- Department of Biological Sciences; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Angela Chiu
- School of Pharmacy; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Joseph Schober
- School of Pharmacy; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Theresa Weber
- School of Pharmacy; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Phuong Nguyen
- School of Pharmacy; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Mark Luer
- School of Pharmacy; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Timothy McPherson
- School of Pharmacy; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Paul E. Wanda
- Department of Biological Sciences; Southern Illinois University Edwardsville; Edwardsville, IL USA
| | - Connie A. Marshall
- Department of Pathology and Immunology; Washington University School of Medicine; St. Louis, MO USA
| | - Nidhi Rohatgi
- Department of Pathology and Immunology; Washington University School of Medicine; St. Louis, MO USA
| | - Michael L. McDaniel
- Department of Pathology and Immunology; Washington University School of Medicine; St. Louis, MO USA
| | - Andrew S. Greenberg
- JM-USDA Human Nutrition Research Center on Aging; Tufts University; Boston, MA USA
| | - Guim Kwon
- School of Pharmacy; Southern Illinois University Edwardsville; Edwardsville, IL USA
- * Correspondence to: Guim Kwon;
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22
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Prentki M, Madiraju SRM. Glycerolipid/free fatty acid cycle and islet β-cell function in health, obesity and diabetes. Mol Cell Endocrinol 2012; 353:88-100. [PMID: 22108437 DOI: 10.1016/j.mce.2011.11.004] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 11/07/2011] [Accepted: 11/07/2011] [Indexed: 12/16/2022]
Abstract
Pancreatic β-cells secrete insulin in response to fluctuations in blood fuel concentrations, in particular glucose and fatty acids. However, chronic fuel surfeit can overwhelm the metabolic, signaling and secretory capacity of the β-cell leading to its dysfunction and death - often referred to as glucolipotoxicity. In β-cells and many other cells, glucose and lipid metabolic pathways converge into a glycerolipid/free fatty acid (GL/FFA) cycle, which is driven by the substrates, glycerol-3-phosphate and fatty acyl-CoA, derived from glucose and fatty acids, respectively. Although the overall operation of GL/FFA cycle, consisting of lipolysis and lipogenesis, is "futile" in terms of energy expenditure, this metabolic cycle likely plays an indispensable role for various β-cell functions, in particular insulin secretion and excess fuel detoxification. In this review, we discuss the significance of GL/FFA cycle in the β-cell, its regulation and role in generating essential metabolic signals that participate in the lipid amplification arm of glucose stimulated insulin secretion and in β-cell growth. We propose the novel concept that the lipolytic segment of GL/FFA cycle is instrumental in producing signals for insulin secretion, whereas, the lipogenic segment generates signals relevant for β-cell survival/death and growth/proliferation.
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Affiliation(s)
- Marc Prentki
- Departments of Nutrition and Biochemistry, University of Montreal, Montreal Diabetes Research Center, CR-CHUM, Technopôle Angus, 2901, Montreal, Canada QC H1W 4A4.
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23
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Pascoe J, Hollern D, Stamateris R, Abbasi M, Romano LC, Zou B, O’Donnell CP, Garcia-Ocana A, Alonso LC. Free fatty acids block glucose-induced β-cell proliferation in mice by inducing cell cycle inhibitors p16 and p18. Diabetes 2012; 61:632-41. [PMID: 22338094 PMCID: PMC3282818 DOI: 10.2337/db11-0991] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Pancreatic β-cell proliferation is infrequent in adult humans and is not increased in type 2 diabetes despite obesity and insulin resistance, suggesting the existence of inhibitory factors. Free fatty acids (FFAs) may influence proliferation. In order to test whether FFAs restrict β-cell proliferation in vivo, mice were intravenously infused with saline, Liposyn II, glucose, or both, continuously for 4 days. Lipid infusion did not alter basal β-cell proliferation, but blocked glucose-stimulated proliferation, without inducing excess β-cell death. In vitro exposure to FFAs inhibited proliferation in both primary mouse β-cells and in rat insulinoma (INS-1) cells, indicating a direct effect on β-cells. Two of the fatty acids present in Liposyn II, linoleic acid and palmitic acid, both reduced proliferation. FFAs did not interfere with cyclin D2 induction or nuclear localization by glucose, but increased expression of inhibitor of cyclin dependent kinase 4 (INK4) family cell cycle inhibitors p16 and p18. Knockdown of either p16 or p18 rescued the antiproliferative effect of FFAs. These data provide evidence for a novel antiproliferative form of β-cell glucolipotoxicity: FFAs restrain glucose-stimulated β-cell proliferation in vivo and in vitro through cell cycle inhibitors p16 and p18. If FFAs reduce proliferation induced by obesity and insulin resistance, targeting this pathway may lead to new treatment approaches to prevent diabetes.
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Affiliation(s)
- Jordan Pascoe
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Douglas Hollern
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rachel Stamateris
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Munira Abbasi
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Lia C. Romano
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Baobo Zou
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Christopher P. O’Donnell
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Adolfo Garcia-Ocana
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Laura C. Alonso
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
- Corresponding author: Laura C. Alonso,
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24
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Delghingaro-Augusto V, Décary S, Peyot ML, Latour MG, Lamontagne J, Paradis-Isler N, Lacharité-Lemieux M, Akakpo H, Birot O, Nolan CJ, Prentki M, Bergeron R. Voluntary running exercise prevents β-cell failure in susceptible islets of the Zucker diabetic fatty rat. Am J Physiol Endocrinol Metab 2012; 302:E254-64. [PMID: 22045312 DOI: 10.1152/ajpendo.00360.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Physical activity improves glycemic control in type 2 diabetes (T2D), but its contribution to preserving β-cell function is uncertain. We evaluated the role of physical activity on β-cell secretory function and glycerolipid/fatty acid (GL/FA) cycling in male Zucker diabetic fatty (ZDF) rats. Six-week-old ZDF rats engaged in voluntary running for 6 wk (ZDF-A). Inactive Zucker lean and ZDF (ZDF-I) rats served as controls. ZDF-I rats displayed progressive hyperglycemia with β-cell failure evidenced by falling insulinemia and reduced insulin secretion to oral glucose. Isolated ZDF-I rat islets showed reduced glucose-stimulated insulin secretion expressed per islet and per islet protein. They were also characterized by loss of the glucose regulation of fatty acid oxidation and GL/FA cycling, reduced mRNA expression of key β-cell genes, and severe reduction of insulin stores. Physical activity prevented diabetes in ZDF rats through sustaining β-cell compensation to insulin resistance shown in vivo and in vitro. Surprisingly, ZDF-A islets had persistent defects in fatty acid oxidation, GL/FA cycling, and β-cell gene expression. ZDF-A islets, however, had preserved islet insulin mRNA and insulin stores compared with ZDF-I rats. Physical activity did not prevent hyperphagia, dyslipidemia, or obesity in ZDF rats. In conclusion, islets of ZDF rats have a susceptibility to failure that is possibly due to altered β-cell fatty acid metabolism. Depletion of pancreatic islet insulin stores is a major contributor to islet failure in this T2D model, preventable by physical activity.
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Affiliation(s)
- Viviane Delghingaro-Augusto
- Molecular Nutrition Unit and The Montreal Diabetes Research Center, Research Center of the University of Montreal Hospital Center,University of Montreal, Quebec, Canada
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25
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Body mass index and outcomes from pancreatic resection: a review and meta-analysis. J Gastrointest Surg 2011; 15:1633-42. [PMID: 21484490 DOI: 10.1007/s11605-011-1502-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 03/23/2011] [Indexed: 01/31/2023]
Abstract
INTRODUCTION There are 1.6 billion adults worldwide who are overweight, with body mass indices (BMI) between 25 and 30, while more than 400 million are obese (BMI >30). Obesity predicts the incidence of and poor outcomes from pancreatic cancer. Obesity has also been linked to surgical complications in pancreatectomy, including increased length of hospital stay, surgical infections, blood loss, and decreased survival. However, BMI's impact on many complications following pancreatectomy remains controversial. METHODS We performed a MEDLINE search of all combinations of "BMI" with "pancreatectomy," "pancreatoduodenectomy," or "pancreaticoduodenectomy." From included studies, we created pooled and weighted estimates for quantitative and qualitative outcomes. We used the PRISMA criteria to ensure this project's validity. RESULTS Our primary cohort included 2,736 patients with BMI <30, 1,682 with BMI >25, and 546 with BMI between 25 and 30. Most outcomes showed no definitive differences across BMIs. Pancreatic fistula (PF) rates ranged from 4.7% to 31.0%, and four studies found multivariate association between BMI and PF (range odds ratio 1.6-4.2). Pooled analyses of PF by BMI showed significant association (p < 0.05). CONCLUSION BMI increases the operative complexity of pancreatectomy. However, with aggressive peri- and post-operative care, increases in BMI-associated morbidity and mortality may be mitigated.
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26
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Tiano JP, Delghingaro-Augusto V, Le May C, Liu S, Kaw MK, Khuder SS, Latour MG, Bhatt SA, Korach KS, Najjar SM, Prentki M, Mauvais-Jarvis F. Estrogen receptor activation reduces lipid synthesis in pancreatic islets and prevents β cell failure in rodent models of type 2 diabetes. J Clin Invest 2011; 121:3331-42. [PMID: 21747171 DOI: 10.1172/jci44564] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 05/18/2011] [Indexed: 12/11/2022] Open
Abstract
The failure of pancreatic β cells to adapt to an increasing demand for insulin is the major mechanism by which patients progress from insulin resistance to type 2 diabetes (T2D) and is thought to be related to dysfunctional lipid homeostasis within those cells. In multiple animal models of diabetes, females demonstrate relative protection from β cell failure. We previously found that the hormone 17β-estradiol (E2) in part mediates this benefit. Here, we show that treating male Zucker diabetic fatty (ZDF) rats with E2 suppressed synthesis and accumulation of fatty acids and glycerolipids in islets and protected against β cell failure. The antilipogenic actions of E2 were recapitulated by pharmacological activation of estrogen receptor α (ERα) or ERβ in a rat β cell line and in cultured ZDF rat, mouse, and human islets. Pancreas-specific null deletion of ERα in mice (PERα-/-) prevented reduction of lipid synthesis by E2 via a direct action in islets, and PERα-/- mice were predisposed to islet lipid accumulation and β cell dysfunction in response to feeding with a high-fat diet. ER activation inhibited β cell lipid synthesis by suppressing the expression (and activity) of fatty acid synthase via a nonclassical pathway dependent on activated Stat3. Accordingly, pancreas-specific deletion of Stat3 in mice curtailed ER-mediated suppression of lipid synthesis. These data suggest that extranuclear ERs may be promising therapeutic targets to prevent β cell failure in T2D.
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Affiliation(s)
- Joseph P Tiano
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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27
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Abstract
Type 2 diabetes is now a pandemic and shows no signs of abatement. In this Seminar we review the pathophysiology of this disorder, with particular attention to epidemiology, genetics, epigenetics, and molecular cell biology. Evidence is emerging that a substantial part of diabetes susceptibility is acquired early in life, probably owing to fetal or neonatal programming via epigenetic phenomena. Maternal and early childhood health might, therefore, be crucial to the development of effective prevention strategies. Diabetes develops because of inadequate islet β-cell and adipose-tissue responses to chronic fuel excess, which results in so-called nutrient spillover, insulin resistance, and metabolic stress. The latter damages multiple organs. Insulin resistance, while forcing β cells to work harder, might also have an important defensive role against nutrient-related toxic effects in tissues such as the heart. Reversal of overnutrition, healing of the β cells, and lessening of adipose tissue defects should be treatment priorities.
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Affiliation(s)
- Christopher J Nolan
- Department of Endocrinology, Canberra Hospital and Australian National University Medical School, Canberra, ACT, Australia.
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Fontés G, Zarrouki B, Hagman DK, Latour MG, Semache M, Roskens V, Moore PC, Prentki M, Rhodes CJ, Jetton TL, Poitout V. Glucolipotoxicity age-dependently impairs beta cell function in rats despite a marked increase in beta cell mass. Diabetologia 2010; 53:2369-79. [PMID: 20628728 PMCID: PMC2947580 DOI: 10.1007/s00125-010-1850-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 06/18/2010] [Indexed: 01/25/2023]
Abstract
AIMS/HYPOTHESIS Prolonged exposure of pancreatic beta cells to excessive levels of glucose and fatty acids, referred to as glucolipotoxicity, is postulated to contribute to impaired glucose homeostasis in patients with type 2 diabetes. However, the relative contribution of defective beta cell function vs diminished beta cell mass under glucolipotoxic conditions in vivo remains a subject of debate. We therefore sought to determine whether glucolipotoxicity in rats is due to impaired beta cell function and/or reduced beta cell mass, and whether older animals are more susceptible to glucolipotoxic condition. METHODS Wistar rats (2 and 6 months old) received a 72 h infusion of glucose + intravenous fat emulsion or saline control. In vivo insulin secretion and sensitivity were assessed by hyperglycaemic clamps. Ex vivo insulin secretion, insulin biosynthesis and gene expression were measured in isolated islets. Beta cell mass and proliferation were examined by immunohistochemistry. RESULTS A 72 h infusion of glucose + intravenous fat emulsion in 2-month-old Wistar rats did not affect insulin sensitivity, insulin secretion or beta cell mass. In 6-month-old rats by contrast it led to insulin resistance and reduced insulin secretion in vivo, despite an increase in beta cell mass and proliferation. This was associated with: (1) diminished glucose-stimulated second-phase insulin secretion and proinsulin biosynthesis; (2) lower insulin content; and (3) reduced expression of beta cell genes in isolated islets. CONCLUSIONS/INTERPRETATION In this in vivo model, glucolipotoxicity is characterised by an age-dependent impairment of glucose-regulated beta cell function despite a marked increase in beta cell mass.
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Affiliation(s)
- G. Fontés
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM–Technopole Angus, 2901 Rachel Est, Montréal, QC, Canada H1W 4A4
- Department of Medicine, University of Montreal, Montreal, QC, Canada
| | - B. Zarrouki
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM–Technopole Angus, 2901 Rachel Est, Montréal, QC, Canada H1W 4A4
- Department of Medicine, University of Montreal, Montreal, QC, Canada
| | - D. K. Hagman
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM–Technopole Angus, 2901 Rachel Est, Montréal, QC, Canada H1W 4A4
- Department of Medicine, University of Montreal, Montreal, QC, Canada
| | - M. G. Latour
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM–Technopole Angus, 2901 Rachel Est, Montréal, QC, Canada H1W 4A4
| | - M. Semache
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM–Technopole Angus, 2901 Rachel Est, Montréal, QC, Canada H1W 4A4
- Department of Biochemistry, University of Montreal, Montreal, QC, Canada
| | - V. Roskens
- Division of Endocrinology, Diabetes and Metabolism, University of Vermont College of Medicine, Burlington, VT, USA
| | - P. C. Moore
- Kovler Diabetes Center, University of Chicago, Chicago, IL, USA
| | - M. Prentki
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM–Technopole Angus, 2901 Rachel Est, Montréal, QC, Canada H1W 4A4
- Department of Nutrition, University of Montreal, Montreal, QC, Canada
- Department of Biochemistry, University of Montreal, Montreal, QC, Canada
| | - C. J. Rhodes
- Kovler Diabetes Center, University of Chicago, Chicago, IL, USA
| | - T. L. Jetton
- Division of Endocrinology, Diabetes and Metabolism, University of Vermont College of Medicine, Burlington, VT, USA
| | - V. Poitout
- Montreal Diabetes Research Center, University of Montreal, Montreal, QC, Canada
- CRCHUM–Technopole Angus, 2901 Rachel Est, Montréal, QC, Canada H1W 4A4,
- Department of Medicine, University of Montreal, Montreal, QC, Canada
- Department of Nutrition, University of Montreal, Montreal, QC, Canada
- Department of Biochemistry, University of Montreal, Montreal, QC, Canada
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Peyot ML, Pepin E, Lamontagne J, Latour MG, Zarrouki B, Lussier R, Pineda M, Jetton TL, Madiraju SRM, Joly E, Prentki M. Beta-cell failure in diet-induced obese mice stratified according to body weight gain: secretory dysfunction and altered islet lipid metabolism without steatosis or reduced beta-cell mass. Diabetes 2010; 59:2178-87. [PMID: 20547980 PMCID: PMC2927940 DOI: 10.2337/db09-1452] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE C57Bl/6 mice develop obesity and mild hyperglycemia when fed a high-fat diet (HFD). Although diet-induced obesity (DIO) is a widely studied model of type 2 diabetes, little is known about beta-cell failure in these mice. RESEARCH DESIGN AND METHODS DIO mice were separated in two groups according to body weight gain: low- and high-HFD responders (LDR and HDR). We examined whether mild hyperglycemia in HDR mice is due to reduced beta-cell mass or function and studied islet metabolism and signaling. RESULTS HDR mice were more obese, hyperinsulinemic, insulin resistant, and hyperglycemic and showed a more altered plasma lipid profile than LDR. LDR mice largely compensated insulin resistance, whereas HDR showed perturbed glucose homeostasis. Neither LDR nor HDR mice showed reduced beta-cell mass, altered islet glucose metabolism, and triglyceride deposition. Insulin secretion in response to glucose, KCl, and arginine was impaired in LDR and almost abolished in HDR islets. Palmitate partially restored glucose- and KCl-stimulated secretion. The glucose-induced rise in ATP was reduced in both DIO groups, and the glucose-induced rise in Ca(2+) was reduced in HDR islets relatively to LDR. Glucose-stimulated lipolysis was decreased in LDR and HDR islets, whereas fat oxidation was increased in HDR islets only. Fatty acid esterification processes were markedly diminished, and free cholesterol accumulated in HDR islets. CONCLUSIONS beta-Cell failure in HDR mice is not due to reduced beta-cell mass and glucose metabolism or steatosis but to a secretory dysfunction that is possibly due to altered ATP/Ca(2+) and lipid signaling, as well as free cholesterol deposition.
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Affiliation(s)
- Marie-Line Peyot
- Montreal Diabetes Research Center and CRCHUM, Montreal, QC, Canada.
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Pepin E, Guay C, Delghingaro-Augusto V, Joly E, Madiraju SRM, Prentki M. Short-chain 3-hydroxyacyl-CoA dehydrogenase is a negative regulator of insulin secretion in response to fuel and non-fuel stimuli in INS832/13 β-cells. J Diabetes 2010; 2:157-67. [PMID: 20923481 DOI: 10.1111/j.1753-0407.2010.00076.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Hyperinsulinemia associated with non-ketotic hypoglycemia is observed in patients with mutated β-oxidation enzyme short-chain 3-hydroxyacyl-CoA dehydrogenase (HADHSC). In the present study, we investigated the mechanism underlying HADHSC-mediated regulation of insulin secretion. METHODS Knockdown of HADHSC expression by RNA interference in INS832/13 β-cells was achieved using short hairpin RNA and short interference RNA. RESULTS Knockdown of HADHSC increased both fuel- (glucose or leucine plus glutamine) and non-fuel (high KCl)-induced insulin secretion. Enhanced glucose-stimulated insulin secretion (GSIS) induced by HADHSC knockdown was independent of changes in cytosolic Ca(2+) and also occurred in the presence of fatty acids. L-Carnitine, used in the formation of acyl-carnitine compounds, increased GSIS in control cells, but was unable to further increase the augmented GSIS in HADHSC-knockdown cells. The pan transaminase inhibitor amino-oxyacetate reversed HADHSC knockdown-mediated increases in GSIS. Oxidation of [1-(14) C]-palmitate and -octanoate was not reduced in HADHSC-knockdown cells. L-3-Hydroxybutyryl-carnitine (tested using its precursor L-3-hydroxybutyrate) and L-3-hydroxyglutarate, which accumulate in blood and urine, respectively, of HADHSC-deficient patients, did not change insulin secretion. CONCLUSIONS Insulin secretion promoted by both fuel and non-fuel stimuli is negatively regulated by HADHSC. Enhanced secretion after HADHSC knockdown is not due to inhibition of fatty acid oxidation causing an accumulation of long-chain fatty acids or their CoA derivatives. L-3-Hydroxybutyrate and L-3-hydroxyglutarate do not mediate enhanced secretion caused by reduced HADHSC activity. Transamination reaction(s) and the formation of short-chain acylcarnitines and CoAs may be implicated in the mechanism whereby HADHSC deficiency results in enhanced insulin secretion and hyperinsulinemia.
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Affiliation(s)
- Emilie Pepin
- Montreal Diabetes Research Center, CRCHUM, Montréal, Québec, Canada
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Abstract
The widespread epidemics of obesity and type 2 diabetes mellitus (T2DM) suggest that both conditions are closely linked. An increasing body of evidence has shifted our view of adipose tissue from a passive energy depot to a dynamic "endocrine organ" that tightly regulates nutritional balance by means of a complex crosstalk of adipocytes with their microenvironment. Dysfunctional adipose tissue, particularly as observed in obesity, is characterized by adipocyte hypertrophy, macrophage infiltration, impaired insulin signaling, and insulin resistance. The result is the release of a host of inflammatory adipokines and excessive amounts of free fatty acids that promote ectopic fat deposition and lipotoxicity in muscle, liver, and pancreatic beta cells. This review focuses on recent work on how glucose homeostasis is profoundly altered by distressed adipose tissue. A better understanding of this relationship offers the best chance for early intervention strategies aimed at preventing the burden of T2DM.
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Affiliation(s)
- Kenneth Cusi
- The University of Texas Health Science Center at San Antonio, Diabetes Division, Room 3.380S, 7703 Floyd Curl Drive, San Antonio, TX 78284-3900, USA.
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Marselli L, Thorne J, Dahiya S, Sgroi DC, Sharma A, Bonner-Weir S, Marchetti P, Weir GC. Gene expression profiles of Beta-cell enriched tissue obtained by laser capture microdissection from subjects with type 2 diabetes. PLoS One 2010; 5:e11499. [PMID: 20644627 PMCID: PMC2903480 DOI: 10.1371/journal.pone.0011499] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Accepted: 06/06/2010] [Indexed: 12/26/2022] Open
Abstract
Background Changes in gene expression in pancreatic beta-cells from type 2 diabetes (T2D) should provide insights into their abnormal insulin secretion and turnover. Methodology/Principal Findings Frozen sections were obtained from cadaver pancreases of 10 control and 10 T2D human subjects. Beta-cell enriched samples were obtained by laser capture microdissection (LCM). RNA was extracted, amplified and subjected to microarray analysis. Further analysis was performed with DNA-Chip Analyzer (dChip) and Gene Set Enrichment Analysis (GSEA) software. There were changes in expression of genes linked to glucotoxicity. Evidence of oxidative stress was provided by upregulation of several metallothionein genes. There were few changes in the major genes associated with cell cycle, apoptosis or endoplasmic reticulum stress. There was differential expression of genes associated with pancreatic regeneration, most notably upregulation of members of the regenerating islet gene (REG) family and metalloproteinase 7 (MMP7). Some of the genes found in GWAS studies to be related to T2D were also found to be differentially expressed. IGF2BP2, TSPAN8, and HNF1B (TCF2) were upregulated while JAZF1 and SLC30A8 were downregulated. Conclusions/Significance This study made possible by LCM has identified many novel changes in gene expression that enhance understanding of the pathogenesis of T2D.
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Affiliation(s)
- Lorella Marselli
- Section on Islet Transplantation and Cell Biology, Research Division, Joslin Diabetes Center and the Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeffrey Thorne
- Section on Islet Transplantation and Cell Biology, Research Division, Joslin Diabetes Center and the Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sonika Dahiya
- Molecular Pathology Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Dennis C. Sgroi
- Molecular Pathology Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Arun Sharma
- Section on Islet Transplantation and Cell Biology, Research Division, Joslin Diabetes Center and the Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Susan Bonner-Weir
- Section on Islet Transplantation and Cell Biology, Research Division, Joslin Diabetes Center and the Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Piero Marchetti
- Section of Endocrinology and Metabolism of Organ Transplantation, Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - Gordon C. Weir
- Section on Islet Transplantation and Cell Biology, Research Division, Joslin Diabetes Center and the Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Gupta D, Peshavaria M, Monga N, Jetton TL, Leahy JL. Physiologic and pharmacologic modulation of glucose-dependent insulinotropic polypeptide (GIP) receptor expression in beta-cells by peroxisome proliferator-activated receptor (PPAR)-gamma signaling: possible mechanism for the GIP resistance in type 2 diabetes. Diabetes 2010; 59:1445-50. [PMID: 20332343 PMCID: PMC2874705 DOI: 10.2337/db09-1655] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE We previously showed that peroxisome proliferator-activated receptor (PPAR)-gamma in beta-cells regulates pdx-1 transcription through a functional PPAR response element (PPRE). Gene Bank blast for a homologous nucleotide sequence revealed the same PPRE within the rat glucose-dependent insulinotropic polypeptide receptor (GIP-R) promoter sequence. We investigated the role of PPARgamma in GIP-R transcription. RESEARCH DESIGN AND METHODS Chromatin immunoprecipitation assay, siRNA, and luciferase gene transcription assay in INS-1 cells were performed. Islet GIP-R expression and immunohistochemistry studies were performed in pancreas-specific PPARgamma knockout mice (PANC PPARgamma(-/-)), normoglycemic 60% pancreatectomy rats (Px), normoglycemic and hyperglycemic Zucker fatty (ZF) rats, and mouse islets incubated with troglitazone. RESULTS In vitro studies of INS-1 cells confirmed that PPAR-gamma binds to the putative PPRE sequence and regulates GIP-R transcription. In vivo verification was shown by a 70% reduction in GIP-R protein expression in islets from PANC PPARgamma(-/-) mice and a twofold increase in islets of 14-day post-60% Px Sprague-Dawley rats that hyperexpress beta-cell PPARgamma. Thiazolidinedione activation (72 h) of this pathway in normal mouse islets caused a threefold increase of GIP-R protein and a doubling of insulin secretion to 16.7 mmol/l glucose/10 nmol/l GIP. Islets from obese normoglycemic ZF rats had twofold increased PPARgamma and GIP-R protein levels versus lean rats, with both lowered by two-thirds in ZF rats made hyperglycemic by 60% Px. CONCLUSIONS Our studies have shown physiologic and pharmacologic regulation of GIP-R expression in beta-cells by PPARgamma signaling. Also disruption of this signaling pathway may account for the lowered beta-cell GIP-R expression and resulting GIP resistance in type 2 diabetes.
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Affiliation(s)
- Dhananjay Gupta
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont
| | - Mina Peshavaria
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont
| | - Navjot Monga
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont
| | - Thomas L. Jetton
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont
| | - Jack L. Leahy
- From the Division of Endocrinology, Diabetes, and Metabolism and the Department of Medicine, University of Vermont, Burlington, Vermont
- Corresponding author: Jack L. Leahy,
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Andrikopoulos S. Obesity and type 2 diabetes: slow down!--Can metabolic deceleration protect the islet beta cell from excess nutrient-induced damage? Mol Cell Endocrinol 2010; 316:140-6. [PMID: 19815054 DOI: 10.1016/j.mce.2009.09.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Revised: 09/08/2009] [Accepted: 09/28/2009] [Indexed: 01/09/2023]
Abstract
Islet beta-cell dysfunction is a characteristic and the main cause of hyperglycaemia of Type 2 diabetes. Understanding the mechanisms that cause beta-cell dysfunction will lead to better therapeutic outcomes for patients with Type 2 diabetes. Chronic fatty acid exposure of susceptible islet beta-cells causes dysfunction and death and this is associated with increased reactive oxygen species production leading to oxidative stress and increased endoplasmic reticulum stress. We present the hypothesis that metabolic deceleration can reduce both oxidative and endoplasmic reticulum stress and lead to improved beta-cell function and viability when exposed to a deleterious fat milieu. This is illustrated by the C57BL/6J mouse which is characterised by reduced insulin secretion and glucose intolerance associated with a mutation in nicotinamide nucleotide transhydrogenase (Nnt) but is resistant to obesity induced diabetes. On the other hand the DBA/2 mouse has comparatively higher insulin secretion and better glucose tolerance associated with increased Nnt activity but is susceptible to obesity-induced diabetes, possibly as a result of increased oxidative stress. We therefore suggest that in states of excess nutrient load, a reduced ability to metabolise this load may protect both the function and viability of beta-cells. Strategies that reduce metabolic flux when beta-cells are exposed to nutrient excess need to be considered when treating Type 2 diabetes.
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Affiliation(s)
- S Andrikopoulos
- Department of Medicine (AH/NH), University of Melbourne, Heidelberg Repatriation Hospital, Heidelberg Heights, Victoria, Australia.
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Abstract
It is well established that the development of NAFLD and NASH are closely linked to an excess flow of free fatty acids (FFA) arising from dysfunctional/insulin resistant adipose tissue causing ectopic fat deposition in many organs. In the liver, when chronic lipid supply surpasses the metabolic ability to adapt it will induce hepatocellular damage as FFA are redirected into harmful pathways of non-oxidative metabolism with intracellular accumulation of toxic lipid-derived metabolites. Multiple mechanisms have been implicated including mitochondrial dysfunction, endoplasmic reticulum stress, and activation of multiple inflammatory pathways. Understanding the role of insulin resistance and lipotoxicity in NASH as part of a broader metabolic disorder is likely to assist practitioners in the successful management of these challenging patients.
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Affiliation(s)
- Kenneth Cusi
- Diabetes Division, The University of Texas Health Science Center at San Antonio, Room 3.380S, 7703 Floyd Curl Drive, San Antonio, TX 78284-3900, USA.
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36
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Current literature in diabetes. Diabetes Metab Res Rev 2009; 25:i-x. [PMID: 19790194 DOI: 10.1002/dmrr.1037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Abstract
Early interventions to prevent type 2 diabetes mellitus (T2DM) demand a better understanding of its underlying mechanisms. Nonobese healthy subjects with a strong family history of T2DM (FH(+) subjects) hold a key to this end by allowing the study of the disease before the development of confounding factors, such as obesity or hyperglycemia. In this article, we share our experience over the past decade in studying FH(+) subjects and how lipotoxicity alters glucose metabolism in such individuals, in particular pancreatic beta-cell function. FH(+) subjects have no obvious clinical abnormalities, but when carefully studied, reveal severe hepatic/muscle/adipose tissue insulin resistance and subtle defects in beta-cell function. In most subjects, metabolic adaption allows freedom from diabetes for decades. However, the obesity epidemic is drastically changing this. Given the unique susceptibility of pancreatic beta cells to free fatty acids in FH(+) subjects, interventions that protect against obesity-induced lipotoxicity may hold the greatest promise for preventing T2DM in genetically predisposed individuals.
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Affiliation(s)
- Kenneth Cusi
- Diabetes Division, Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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Peyot ML, Guay C, Latour MG, Lamontagne J, Lussier R, Pineda M, Ruderman NB, Haemmerle G, Zechner R, Joly É, Madiraju SRM, Poitout V, Prentki M. Adipose triglyceride lipase is implicated in fuel- and non-fuel-stimulated insulin secretion. J Biol Chem 2009; 284:16848-16859. [PMID: 19389712 DOI: 10.1074/jbc.m109.006650] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Reduced lipolysis in hormone-sensitive lipase-deficient mice is associated with impaired glucose-stimulated insulin secretion (GSIS), suggesting that endogenous beta-cell lipid stores provide signaling molecules for insulin release. Measurements of lipolysis and triglyceride (TG) lipase activity in islets from HSL(-/-) mice indicated the presence of other TG lipase(s) in the beta-cell. Using real time-quantitative PCR, adipose triglyceride lipase (ATGL) was found to be the most abundant TG lipase in rat islets and INS832/13 cells. To assess its role in insulin secretion, ATGL expression was decreased in INS832/13 cells (ATGL-knockdown (KD)) by small hairpin RNA. ATGL-KD increased the esterification of free fatty acid (FFA) into TG. ATGL-KD cells showed decreased glucose- or Gln + Leu-induced insulin release, as well as reduced response to KCl or palmitate at high, but not low, glucose. The K(ATP)-independent/amplification pathway of GSIS was considerably reduced in ATGL-KD cells. ATGL(-/-) mice were hypoinsulinemic and hypoglycemic and showed decreased plasma TG and FFAs. A hyperglycemic clamp revealed increased insulin sensitivity and decreased GSIS and arginine-induced insulin secretion in ATGL(-/-) mice. Accordingly, isolated islets from ATGL(-/-) mice showed reduced insulin secretion in response to glucose, glucose + palmitate, and KCl. Islet TG content and FFA esterification into TG were increased by 2-fold in ATGL(-/-) islets, but glucose usage and oxidation were unaltered. The results demonstrate the importance of ATGL and intracellular lipid signaling for fuel- and non-fuel-induced insulin secretion.
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Affiliation(s)
- Marie-Line Peyot
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - Claudiane Guay
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - Martin G Latour
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - Julien Lamontagne
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - Roxane Lussier
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - Marco Pineda
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - Neil B Ruderman
- Departments of Medicine and Physiology and Biophysics, Boston University School of Medicine and Diabetes Unit, Section of Endocrinology, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts 02118
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, Karl-Franzens-University, Graz 8010, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, Karl-Franzens-University, Graz 8010, Austria
| | - Érik Joly
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - S R Murthy Madiraju
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada
| | - Vincent Poitout
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada; Departments of Nutrition, Montreal, Quebec H1W 4A4, Canada; Medicine, University of Montreal, Montreal, Quebec H1W 4A4, Canada
| | - Marc Prentki
- From the Molecular Nutrition Unit and the Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H1W 4A4, Canada; Departments of Nutrition, Montreal, Quebec H1W 4A4, Canada.
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