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Jabůrek M, Klöppel E, Průchová P, Mozheitova O, Tauber J, Engstová H, Ježek P. Mitochondria to plasma membrane redox signaling is essential for fatty acid β-oxidation-driven insulin secretion. Redox Biol 2024; 75:103283. [PMID: 39067330 PMCID: PMC11332078 DOI: 10.1016/j.redox.2024.103283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Revised: 07/22/2024] [Accepted: 07/22/2024] [Indexed: 07/30/2024] Open
Abstract
We asked whether acute redox signaling from mitochondria exists concomitantly to fatty acid- (FA-) stimulated insulin secretion (FASIS) at low glucose by pancreatic β-cells. We show that FA β-oxidation produces superoxide/H2O2, providing: i) mitochondria-to-plasma-membrane redox signaling, closing KATP-channels synergically with elevated ATP (substituting NADPH-oxidase-4-mediated H2O2-signaling upon glucose-stimulated insulin secretion); ii) activation of redox-sensitive phospholipase iPLA2γ/PNPLA8, cleaving mitochondrial FAs, enabling metabotropic GPR40 receptors to amplify insulin secretion (IS). At fasting glucose, palmitic acid stimulated IS in wt mice; palmitic, stearic, lauric, oleic, linoleic, and hexanoic acids also in perifused pancreatic islets (PIs), with suppressed 1st phases in iPLA2γ/PNPLA8-knockout mice/PIs. Extracellular/cytosolic H2O2-monitoring indicated knockout-independent redox signals, blocked by mitochondrial antioxidant SkQ1, etomoxir, CPT1 silencing, and catalase overexpression, all inhibiting FASIS, keeping ATP-sensitive K+-channels open, and diminishing cytosolic [Ca2+]-oscillations. FASIS in mice was a postprandially delayed physiological event. Redox signals of FA β-oxidation are thus documented, reaching the plasma membrane, essentially co-stimulating IS.
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Affiliation(s)
- Martin Jabůrek
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Eduardo Klöppel
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Pavla Průchová
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Oleksandra Mozheitova
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Jan Tauber
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Hana Engstová
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Petr Ježek
- Department of Mitochondrial Physiology, No.75, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic.
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Ježek P, Dlasková A, Engstová H, Špačková J, Tauber J, Průchová P, Kloppel E, Mozheitova O, Jabůrek M. Mitochondrial Physiology of Cellular Redox Regulations. Physiol Res 2024; 73:S217-S242. [PMID: 38647168 DOI: 10.33549/physiolres.935269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
Mitochondria (mt) represent the vital hub of the molecular physiology of the cell, being decision-makers in cell life/death and information signaling, including major redox regulations and redox signaling. Now we review recent advances in understanding mitochondrial redox homeostasis, including superoxide sources and H2O2 consumers, i.e., antioxidant mechanisms, as well as exemplar situations of physiological redox signaling, including the intramitochondrial one and mt-to-cytosol redox signals, which may be classified as acute and long-term signals. This review exemplifies the acute redox signals in hypoxic cell adaptation and upon insulin secretion in pancreatic beta-cells. We also show how metabolic changes under these circumstances are linked to mitochondrial cristae narrowing at higher intensity of ATP synthesis. Also, we will discuss major redox buffers, namely the peroxiredoxin system, which may also promote redox signaling. We will point out that pathological thresholds exist, specific for each cell type, above which the superoxide sources exceed regular antioxidant capacity and the concomitant harmful processes of oxidative stress subsequently initiate etiology of numerous diseases. The redox signaling may be impaired when sunk in such excessive pro-oxidative state.
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Affiliation(s)
- P Ježek
- Laboratory of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
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Kopp W. Aging and "Age-Related" Diseases - What Is the Relation? Aging Dis 2024:AD.2024.0570. [PMID: 39012663 DOI: 10.14336/ad.2024.0570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 06/28/2024] [Indexed: 07/17/2024] Open
Abstract
The study explores the intricate relationship between aging and the development of noncommunicable diseases [NCDs], focusing on whether these diseases are inevitable consequences of aging or primarily driven by lifestyle factors. By examining epidemiological data, particularly from hunter-gatherer societies, the study highlights that many NCDs prevalent in modern populations are rare in these societies, suggesting a significant influence of lifestyle choices. It delves into the mechanisms through which poor diet, smoking, and other lifestyle factors contribute to systemic physiological imbalances, characterized by oxidative stress, insulin resistance and hyperinsulinemia, and dysregulation of the sympathetic nervous system, the renin-angiotensin-aldosterone system, and the immune system. The interplay between this pattern and individual factors such as genetic susceptibility, biological variability, epigenetic changes and the microbiome is proposed to play a crucial role in the development of a range of age-related NCDs. Modified biomolecules such as oxysterols and advanced glycation end products also contribute to their development. Specific diseases such as benign prostatic hyperplasia, Parkinson's disease, glaucoma and osteoarthritis are analyzed to illustrate these mechanisms. The study concludes that while aging contributes to the risk of NCDs, lifestyle factors play a crucial role, offering potential avenues for prevention and intervention through healthier living practices. One possible approach could be to try to restore the physiological balance, e.g. through dietary measures [e.g. Mediterranean diet, Okinawan diet or Paleolithic diet] in conjunction with [a combination of] pharmacological interventions and other lifestyle changes.
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Janssen JAMJL. Overnutrition, Hyperinsulinemia and Ectopic Fat: It Is Time for A Paradigm Shift in the Management of Type 2 Diabetes. Int J Mol Sci 2024; 25:5488. [PMID: 38791525 PMCID: PMC11121669 DOI: 10.3390/ijms25105488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/12/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
The worldwide incidence of prediabetes/type 2 has continued to rise the last 40 years. In the same period, the mean daily energy intake has increased, and the quality of food has significantly changed. The chronic exposure of pancreatic β-cells to calorie excess (excessive energy intake) and food additives may increase pancreatic insulin secretion, decrease insulin pulses and/or reduce hepatic insulin clearance, thereby causing chronic hyperinsulinemia and peripheral insulin resistance. Chronic calorie excess and hyperinsulinemia may promote lipogenesis, inhibit lipolysis and increase lipid storage in adipocytes. In addition, calorie excess and hyperinsulinemia can induce insulin resistance and contribute to progressive and excessive ectopic fat accumulation in the liver and pancreas by the conversion of excess calories into fat. The personal fat threshold hypothesis proposes that in susceptible individuals, excessive ectopic fat accumulation may eventually lead to hepatic insulin receptor resistance, the loss of pancreatic insulin secretion, hyperglycemia and the development of frank type 2 diabetes. Thus, type 2 diabetes seems (partly) to be caused by hyperinsulinemia-induced excess ectopic fat accumulation in the liver and pancreas. Increasing evidence further shows that interventions (hypocaloric diet and/or bariatric surgery), which remove ectopic fat in the liver and pancreas by introducing a negative energy balance, can normalize insulin secretion and glucose tolerance and induce the sustained biochemical remission of type 2 diabetes. This pathophysiological insight may have major implications and may cause a paradigm shift in the management of type 2 diabetes: avoiding/reducing ectopic fat accumulation in the liver and pancreas may both be essential to prevent and cure type 2 diabetes.
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Affiliation(s)
- Joseph A M J L Janssen
- Department of Internal Medicine, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
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5
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Heindel JJ, Lustig RH, Howard S, Corkey BE. Obesogens: a unifying theory for the global rise in obesity. Int J Obes (Lond) 2024; 48:449-460. [PMID: 38212644 PMCID: PMC10978495 DOI: 10.1038/s41366-024-01460-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/14/2023] [Accepted: 01/02/2024] [Indexed: 01/13/2024]
Abstract
Despite varied treatment, mitigation, and prevention efforts, the global prevalence and severity of obesity continue to worsen. Here we propose a combined model of obesity, a unifying paradigm that links four general models: the energy balance model (EBM), based on calories as the driver of weight gain; the carbohydrate-insulin model (CIM), based on insulin as a driver of energy storage; the oxidation-reduction model (REDOX), based on reactive oxygen species (ROS) as a driver of altered metabolic signaling; and the obesogens model (OBS), which proposes that environmental chemicals interfere with hormonal signaling leading to adiposity. We propose a combined OBS/REDOX model in which environmental chemicals (in air, food, food packaging, and household products) generate false autocrine and endocrine metabolic signals, including ROS, that subvert standard regulatory energy mechanisms, increase basal and stimulated insulin secretion, disrupt energy efficiency, and influence appetite and energy expenditure leading to weight gain. This combined model incorporates the data supporting the EBM and CIM models, thus creating one integrated model that covers significant aspects of all the mechanisms potentially contributing to the obesity pandemic. Importantly, the OBS/REDOX model provides a rationale and approach for future preventative efforts based on environmental chemical exposure reduction.
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Affiliation(s)
- Jerrold J Heindel
- Healthy Environment and Endocrine Disruptor Strategies (HEEDS), Bozeman, MT, 59715, USA.
| | - Robert H Lustig
- Department of Pediatrics and Institute for Health Policy Studies, University of California, San Francisco, CA, 94143, USA
| | - Sarah Howard
- Healthy Environment and Endocrine Disruptor Strategies (HEEDS), Bozeman, MT, 59715, USA
| | - Barbara E Corkey
- Department of Medicine, Boston University, Chobanian and Avedisian School of Medicine, Boston, MA, 02118, USA
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Gonzalez P, Dos Santos A, Darnaud M, Moniaux N, Rapoud D, Lacoste C, Nguyen TS, Moullé VS, Deshayes A, Amouyal G, Amouyal P, Bréchot C, Cruciani-Guglielmacci C, Andréelli F, Magnan C, Faivre J. Antimicrobial protein REG3A regulates glucose homeostasis and insulin resistance in obese diabetic mice. Commun Biol 2023; 6:269. [PMID: 36918710 PMCID: PMC10015038 DOI: 10.1038/s42003-023-04616-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 02/21/2023] [Indexed: 03/16/2023] Open
Abstract
Innate immune mediators of pathogen clearance, including the secreted C-type lectins REG3 of the antimicrobial peptide (AMP) family, are known to be involved in the regulation of tissue repair and homeostasis. Their role in metabolic homeostasis remains unknown. Here we show that an increase in human REG3A improves glucose and lipid homeostasis in nutritional and genetic mouse models of obesity and type 2 diabetes. Mice overexpressing REG3A in the liver show improved glucose homeostasis, which is reflected in better insulin sensitivity in normal weight and obese states. Delivery of recombinant REG3A protein to leptin-deficient ob/ob mice or wild-type mice on a high-fat diet also improves glucose homeostasis. This is accompanied by reduced oxidative protein damage, increased AMPK phosphorylation and insulin-stimulated glucose uptake in skeletal muscle tissue. Oxidative damage in differentiated C2C12 myotubes is greatly attenuated by REG3A, as is the increase in gp130-mediated AMPK activation. In contrast, Akt-mediated insulin action, which is impaired by oxidative stress, is not restored by REG3A. These data highlight the importance of REG3A in controlling oxidative protein damage involved in energy and metabolic pathways during obesity and diabetes, and provide additional insight into the dual function of host-immune defense and metabolic regulation for AMP.
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Affiliation(s)
- Patrick Gonzalez
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | - Alexandre Dos Santos
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | - Marion Darnaud
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | - Nicolas Moniaux
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | - Delphine Rapoud
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | - Claire Lacoste
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | - Tung-Son Nguyen
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | - Valentine S Moullé
- Université of Paris, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Paris, 75013, France
| | - Alice Deshayes
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France
| | | | | | | | | | - Fabrizio Andréelli
- Sorbonne Université, INSERM, NutriOmics team, Institute of Cardiometabolism and Nutrition (ICAN), Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris, 75013, France
| | - Christophe Magnan
- Université of Paris, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Paris, 75013, France
| | - Jamila Faivre
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif, 94800, France.
- Université Paris-Saclay, Faculté de Médecine Le Kremlin-Bicêtre, Le Kremlin-Bicêtre, 94270, France.
- Assistance Publique-Hôpitaux de Paris (AP-HP). Université Paris Saclay, Medical-University Department (DMU) Biology, Genetics, Pharmacy, Paul-Brousse Hospital, Villejuif, 94800, France.
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7
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Montera VDSP, Martins APB, Mais LA, Canella DS. Information on food additives on food labels in Brazil: a critical analysis. Rev Saude Publica 2023; 57:2. [PMID: 36820681 PMCID: PMC9933643 DOI: 10.11606/s1518-8787.2023057004371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 07/08/2022] [Indexed: 02/19/2023] Open
Abstract
Questions about the safety of food additives and their consumption have been raised in recent years. The increased exposure to these substances, either by intake of ultra-processed foods or by the broad use and combination of various categories of additives, may be related to higher risks to consumer health. This article comments on the results of a study that quantified and characterized food additives found on the labels of 9,856 packaged foods and beverages available in Brazilian supermarkets. The study adopted a field diary method to record and analyze nonconformities in the lists of ingredients. The objective of this article is to discuss the use of additives identified on the labels and the limitations of Brazilian legislation, which should guarantee the right to information and health.
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Affiliation(s)
- Vanessa dos Santos Pereira Montera
- Universidade do Estado do Rio de JaneiroInstituto de NutriçãoPrograma de Pós-graduação em Alimentação, Nutrição e SaúdeRio de JaneiroRJBrasil Universidade do Estado do Rio de Janeiro. Instituto de Nutrição. Programa de Pós-graduação em Alimentação, Nutrição e Saúde. Rio de Janeiro, RJ, Brasil
| | - Ana Paula Bortoletto Martins
- Universidade de São PauloFaculdade de Saúde PúblicaNúcleo de Pesquisas Epidemiológicas em Nutrição e SaúdeSão PauloSPBrasil Universidade de São Paulo. Faculdade de Saúde Pública. Núcleo de Pesquisas Epidemiológicas em Nutrição e Saúde. São Paulo, SP, Brasil
| | - Laís Amaral Mais
- Instituto Brasileiro de Defesa do ConsumidorSão PauloSPBrasil Instituto Brasileiro de Defesa do Consumidor. São Paulo, SP, Brasil
| | - Daniela Silva Canella
- Universidade de São PauloFaculdade de Saúde PúblicaNúcleo de Pesquisas Epidemiológicas em Nutrição e SaúdeSão PauloSPBrasil Universidade de São Paulo. Faculdade de Saúde Pública. Núcleo de Pesquisas Epidemiológicas em Nutrição e Saúde. São Paulo, SP, Brasil,Universidade do Estado do Rio de JaneiroInstituto de Nutrição Departamento de Nutrição AplicadaRio de JaneiroRJBrasil Universidade do Estado do Rio de Janeiro. Instituto de Nutrição. Departamento de Nutrição Aplicada. Rio de Janeiro, RJ, Brasil
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8
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Kopp W. Pathogenesis of (smoking-related) non-communicable diseases-Evidence for a common underlying pathophysiological pattern. Front Physiol 2022; 13:1037750. [PMID: 36589440 PMCID: PMC9798240 DOI: 10.3389/fphys.2022.1037750] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
Non-communicable diseases, like diabetes, cardiovascular diseases, cancer, stroke, chronic obstructive pulmonary disease, osteoporosis, arthritis, Alzheimer's disease and other more are a leading cause of death in almost all countries. Lifestyle factors, especially poor diet and tobacco consumption, are considered to be the most important influencing factors in the development of these diseases. The Western diet has been shown to cause a significant distortion of normal physiology, characterized by dysregulation of the sympathetic nervous system, renin-angiotensin aldosterone system, and immune system, as well as disruption of physiological insulin and oxidant/antioxidant homeostasis, all of which play critical roles in the development of these diseases. This paper addresses the question of whether the development of smoking-related non-communicable diseases follows the same pathophysiological pattern. The evidence presented shows that exposure to cigarette smoke and/or nicotine causes the same complex dysregulation of physiology as described above, it further shows that the factors involved are strongly interrelated, and that all of these factors play a key role in the development of a broad spectrum of smoking-related diseases. Since not all smokers develop one or more of these diseases, it is proposed that this disruption of normal physiological balance represents a kind of pathogenetic "basic toolkit" for the potential development of a range of non-communicable diseases, and that the decision of whether and what disease will develop in an individual is determined by other, individual factors ("determinants"), such as the genome, epigenome, exposome, microbiome, and others. The common pathophysiological pattern underlying these diseases may provide an explanation for the often poorly understood links between non-communicable diseases and disease comorbidities. The proposed pathophysiological process offers new insights into the development of non-communicable diseases and may influence the direction of future research in both prevention and therapy.
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Avram VF, Merce AP, Hâncu IM, Bătrân AD, Kennedy G, Rosca MG, Muntean DM. Impairment of Mitochondrial Respiration in Metabolic Diseases: An Overview. Int J Mol Sci 2022; 23:8852. [PMID: 36012137 PMCID: PMC9408127 DOI: 10.3390/ijms23168852] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/05/2022] [Accepted: 08/06/2022] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial dysfunction has emerged as a central pathomechanism in the setting of obesity and diabetes mellitus, linking these intertwined pathologies that share insulin resistance as a common denominator. High-resolution respirometry (HRR) is a state-of-the-art research method currently used to study mitochondrial respiration and its impairment in health and disease. Tissue samples, cells or isolated mitochondria are exposed to various substrate-uncoupler-inhibitor-titration protocols, which allows the measurement and calculation of several parameters of mitochondrial respiration. In this review, we discuss the alterations of mitochondrial bioenergetics in the main dysfunctional organs that contribute to the development of the obese and diabetic phenotypes in both animal models and human subjects. Herein we review data regarding the impairment of oxidative phosphorylation as integrated mitochondrial function assessed by means of HRR. We acknowledge the critical role of this method in determining the alterations in oxidative phosphorylation occurring in the early stages of metabolic pathologies. We conclude that there is a mutual two-way relationship between mitochondrial dysfunction and insulin insensitivity that characterizes these diseases.
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Affiliation(s)
- Vlad Florian Avram
- Department VII Internal Medicine—Diabetes, Nutrition and Metabolic Diseases, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
- Center for Molecular Research in Nephrology and Vascular Disease, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
| | - Adrian Petru Merce
- Doctoral School Medicine—Pharmacy, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
- Center for Translational Research and Systems Medicine, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
| | - Iasmina Maria Hâncu
- Doctoral School Medicine—Pharmacy, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
- Center for Translational Research and Systems Medicine, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
| | - Alina Doruța Bătrân
- Doctoral School Medicine—Pharmacy, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
- Center for Translational Research and Systems Medicine, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
| | - Gabrielle Kennedy
- Department of Foundational Sciences, Central Michigan University College of Medicine, Mount Pleasant, MI 48858, USA
| | - Mariana Georgeta Rosca
- Department of Foundational Sciences, Central Michigan University College of Medicine, Mount Pleasant, MI 48858, USA
| | - Danina Mirela Muntean
- Center for Translational Research and Systems Medicine, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
- Department III Functional Sciences—Pathophysiology, “Victor Babeș” University of Medicine and Pharmacy, Eftimie Murgu Sq. No. 2, 300041 Timișoara, Romania
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10
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Janssen JAMJL. Hyperinsulinemia and Its Pivotal Role in Aging, Obesity, Type 2 Diabetes, Cardiovascular Disease and Cancer. Int J Mol Sci 2021; 22:ijms22157797. [PMID: 34360563 PMCID: PMC8345990 DOI: 10.3390/ijms22157797] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 01/10/2023] Open
Abstract
For many years, the dogma has been that insulin resistance precedes the development of hyperinsulinemia. However, recent data suggest a reverse order and place hyperinsulinemia mechanistically upstream of insulin resistance. Genetic background, consumption of the “modern” Western diet and over-nutrition may increase insulin secretion, decrease insulin pulses and/or reduce hepatic insulin clearance, thereby causing hyperinsulinemia. Hyperinsulinemia disturbs the balance of the insulin–GH–IGF axis and shifts the insulin : GH ratio towards insulin and away from GH. This insulin–GH shift promotes energy storage and lipid synthesis and hinders lipid breakdown, resulting in obesity due to higher fat accumulation and lower energy expenditure. Hyperinsulinemia is an important etiological factor in the development of metabolic syndrome, type 2 diabetes, cardiovascular disease, cancer and premature mortality. It has been further hypothesized that nutritionally driven insulin exposure controls the rate of mammalian aging. Interventions that normalize/reduce plasma insulin concentrations might play a key role in the prevention and treatment of age-related decline, obesity, type 2 diabetes, cardiovascular disease and cancer. Caloric restriction, increasing hepatic insulin clearance and maximizing insulin sensitivity are at present the three main strategies available for managing hyperinsulinemia. This may slow down age-related physiological decline and prevent age-related diseases. Drugs that reduce insulin (hyper) secretion, normalize pulsatile insulin secretion and/or increase hepatic insulin clearance may also have the potential to prevent or delay the progression of hyperinsulinemia-mediated diseases. Future research should focus on new strategies to minimize hyperinsulinemia at an early stage, aiming at successfully preventing and treating hyperinsulinemia-mediated diseases.
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Affiliation(s)
- Joseph A M J L Janssen
- Department of internal Medicine, Division of Endocrinology, Erasmus Medical Center, 40, 3015 GD Rotterdam, The Netherlands
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11
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Elumalai S, Karunakaran U, Moon JS, Won KC. NADPH Oxidase (NOX) Targeting in Diabetes: A Special Emphasis on Pancreatic β-Cell Dysfunction. Cells 2021; 10:cells10071573. [PMID: 34206537 PMCID: PMC8307876 DOI: 10.3390/cells10071573] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/12/2021] [Accepted: 06/16/2021] [Indexed: 12/24/2022] Open
Abstract
In type 2 diabetes, metabolic stress has a negative impact on pancreatic β-cell function and survival (T2D). Although the pathogenesis of metabolic stress is complex, an imbalance in redox homeostasis causes abnormal tissue damage and β-cell death due to low endogenous antioxidant expression levels in β-cells. Under diabetogenic conditions, the susceptibility of β-cells to oxidative damage by NADPH oxidase has been related to contributing to β-cell dysfunction. Here, we consider recent insights into how the redox response becomes deregulated under diabetic conditions by NADPH oxidase, as well as the therapeutic benefits of NOX inhibitors, which may provide clues for understanding the pathomechanisms and developing strategies aimed at the treatment or prevention of metabolic stress associated with β-cell failure.
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Affiliation(s)
- Suma Elumalai
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (S.E.); (U.K.)
| | - Udayakumar Karunakaran
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (S.E.); (U.K.)
| | - Jun-Sung Moon
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (S.E.); (U.K.)
- Department of Internal Medicine, Yeungnam Universtiy College of Medicine, Daegu 42415, Korea
- Correspondence: (J.-S.M.); (K.-C.W.); Tel.: +82-53-620-3825 (J.-S.W.); +82-53-620-3846 (K.-C.W.)
| | - Kyu-Chang Won
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (S.E.); (U.K.)
- Department of Internal Medicine, Yeungnam Universtiy College of Medicine, Daegu 42415, Korea
- Correspondence: (J.-S.M.); (K.-C.W.); Tel.: +82-53-620-3825 (J.-S.W.); +82-53-620-3846 (K.-C.W.)
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12
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Ježek P, Holendová B, Jabůrek M, Tauber J, Dlasková A, Plecitá-Hlavatá L. The Pancreatic β-Cell: The Perfect Redox System. Antioxidants (Basel) 2021; 10:antiox10020197. [PMID: 33572903 PMCID: PMC7912581 DOI: 10.3390/antiox10020197] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Pancreatic β-cell insulin secretion, which responds to various secretagogues and hormonal regulations, is reviewed here, emphasizing the fundamental redox signaling by NADPH oxidase 4- (NOX4-) mediated H2O2 production for glucose-stimulated insulin secretion (GSIS). There is a logical summation that integrates both metabolic plus redox homeostasis because the ATP-sensitive K+ channel (KATP) can only be closed when both ATP and H2O2 are elevated. Otherwise ATP would block KATP, while H2O2 would activate any of the redox-sensitive nonspecific calcium channels (NSCCs), such as TRPM2. Notably, a 100%-closed KATP ensemble is insufficient to reach the -50 mV threshold plasma membrane depolarization required for the activation of voltage-dependent Ca2+ channels. Open synergic NSCCs or Cl- channels have to act simultaneously to reach this threshold. The resulting intermittent cytosolic Ca2+-increases lead to the pulsatile exocytosis of insulin granule vesicles (IGVs). The incretin (e.g., GLP-1) amplification of GSIS stems from receptor signaling leading to activating the phosphorylation of TRPM channels and effects on other channels to intensify integral Ca2+-influx (fortified by endoplasmic reticulum Ca2+). ATP plus H2O2 are also required for branched-chain ketoacids (BCKAs); and partly for fatty acids (FAs) to secrete insulin, while BCKA or FA β-oxidation provide redox signaling from mitochondria, which proceeds by H2O2 diffusion or hypothetical SH relay via peroxiredoxin "redox kiss" to target proteins.
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13
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Ntamo Y, Samodien E, Burger J, Muller N, Muller CJF, Chellan N. In vitro Characterization of Insulin-Producing β-Cell Spheroids. Front Cell Dev Biol 2021; 8:623889. [PMID: 33585464 PMCID: PMC7876261 DOI: 10.3389/fcell.2020.623889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/23/2020] [Indexed: 12/18/2022] Open
Abstract
Over the years, immortalized rodent β-cell lines such as RIN, HIT, MIN, βTC, and INS-1 have been used to investigate pancreatic β-cell physiology using conventional two-dimensional (2D) culture techniques. However, physical and physiological limitations inherent to 2D cell culture necessitates confirmatory follow up studies using sentient animals. Three-dimensional (3D) culture models are gaining popularity for their recapitulation of key features of in vivo organ physiology, and thus could pose as potential surrogates for animal experiments. In this study, we aimed to develop and characterize a rat insulinoma INS-1 3D spheroid model to compare with 2D monolayers of the same cell line. Ultrastructural verification was done by transmission electron microscopy and toluidine blue staining, which showed that both 2D monolayers and 3D spheroids contained highly granulated cells with ultrastructural features synonymous with mature pancreatic β-cells, with increased prominence of these features observed in 3D spheroids. Viability, as assessed by cellular ATP quantification, size profiling and glucose utilization, showed that our spheroids remained viable for the experimental period of 30 days, compared to the limiting 5-day passage period of INS-1 monolayers. In fact, increasing ATP content together with spheroid size was observed over time, without adverse changes in glucose utilization. Additionally, β-cell function, assessed by determining insulin and amylin secretion, showed that the 3D spheroids retained glucose sensing and insulin secretory capability, that was more acute when compared to 2D monolayer cultures. Thus, we were able to successfully demonstrate that our in vitro INS-1 β-cell 3D spheroid model exhibits in vivo tissue-like structural features with extended viability and lifespan. This offers enhanced predictive capacity of the model in the study of metabolic disease, β-cell pathophysiology and the potential treatment thereof.
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Affiliation(s)
- Yonela Ntamo
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa, South Africa
| | - Ebrahim Samodien
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa
| | - Joleen Burger
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nolan Muller
- National Health Laboratory Service, Anatomical Pathology, Tygerberg Hospital, Cape Town, South Africa
| | - Christo J F Muller
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nireshni Chellan
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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14
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Andersen PAK, Petrenko V, Rose PH, Koomen M, Fischer N, Ghiasi SM, Dahlby T, Dibner C, Mandrup-Poulsen T. Proinflammatory Cytokines Perturb Mouse and Human Pancreatic Islet Circadian Rhythmicity and Induce Uncoordinated β-Cell Clock Gene Expression via Nitric Oxide, Lysine Deacetylases, and Immunoproteasomal Activity. Int J Mol Sci 2020; 22:E83. [PMID: 33374803 PMCID: PMC7795908 DOI: 10.3390/ijms22010083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
Pancreatic β-cell-specific clock knockout mice develop β-cell oxidative-stress and failure, as well as glucose-intolerance. How inflammatory stress affects the cellular clock is under-investigated. Real-time recording of Per2:luciferase reporter activity in murine and human pancreatic islets demonstrated that the proinflammatory cytokine interleukin-1β (IL-1β) lengthened the circadian period. qPCR-profiling of core clock gene expression in insulin-producing cells suggested that the combination of the proinflammatory cytokines IL-1β and interferon-γ (IFN-γ) caused pronounced but uncoordinated increases in mRNA levels of multiple core clock genes, in particular of reverse-erythroblastosis virus α (Rev-erbα), in a dose- and time-dependent manner. The REV-ERBα/β agonist SR9009, used to mimic cytokine-mediated Rev-erbα induction, reduced constitutive and cytokine-induced brain and muscle arnt-like 1 (Bmal1) mRNA levels in INS-1 cells as expected. SR9009 induced reactive oxygen species (ROS), reduced insulin-1/2 (Ins-1/2) mRNA and accumulated- and glucose-stimulated insulin secretion, reduced cell viability, and increased apoptosis levels, reminiscent of cytokine toxicity. In contrast, low (<5,0 μM) concentrations of SR9009 increased Ins-1 mRNA and accumulated insulin-secretion without affecting INS-1 cell viability, mirroring low-concentration IL-1β mediated β-cell stimulation. Inhibiting nitric oxide (NO) synthesis, the lysine deacetylase HDAC3 and the immunoproteasome reduced cytokine-mediated increases in clock gene expression. In conclusion, the cytokine-combination perturbed the intrinsic clocks operative in mouse and human pancreatic islets and induced uncoordinated clock gene expression in INS-1 cells, the latter effect associated with NO, HDAC3, and immunoproteasome activity.
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Affiliation(s)
- Phillip Alexander Keller Andersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark; (P.A.K.A.); (P.H.R.); (M.K.); (N.F.); (S.M.G.); (T.D.)
| | - Volodymyr Petrenko
- Division of Endocrinology, Diabetes, Nutrition and Patient Education, Department of Cell Physiology and Metabolism, Diabetes Center, Faculty of Medicine, University of Geneva, D05.2147c Rue Michel-Servet, 1 CH-1211 Geneva 4, Switzerland; (V.P.); (C.D.)
| | - Peter Horskjær Rose
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark; (P.A.K.A.); (P.H.R.); (M.K.); (N.F.); (S.M.G.); (T.D.)
| | - Melissa Koomen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark; (P.A.K.A.); (P.H.R.); (M.K.); (N.F.); (S.M.G.); (T.D.)
| | - Nico Fischer
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark; (P.A.K.A.); (P.H.R.); (M.K.); (N.F.); (S.M.G.); (T.D.)
| | - Seyed Mojtaba Ghiasi
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark; (P.A.K.A.); (P.H.R.); (M.K.); (N.F.); (S.M.G.); (T.D.)
| | - Tina Dahlby
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark; (P.A.K.A.); (P.H.R.); (M.K.); (N.F.); (S.M.G.); (T.D.)
| | - Charna Dibner
- Division of Endocrinology, Diabetes, Nutrition and Patient Education, Department of Cell Physiology and Metabolism, Diabetes Center, Faculty of Medicine, University of Geneva, D05.2147c Rue Michel-Servet, 1 CH-1211 Geneva 4, Switzerland; (V.P.); (C.D.)
| | - Thomas Mandrup-Poulsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark; (P.A.K.A.); (P.H.R.); (M.K.); (N.F.); (S.M.G.); (T.D.)
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15
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Corkey BE, Deeney JT. The Redox Communication Network as a Regulator of Metabolism. Front Physiol 2020; 11:567796. [PMID: 33178037 PMCID: PMC7593883 DOI: 10.3389/fphys.2020.567796] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/22/2020] [Indexed: 12/14/2022] Open
Abstract
Key tissues are dysfunctional in obesity, diabetes, cardiovascular disease, fatty liver and other metabolic diseases. Focus has centered on individual organs as though each was isolated. Attention has been paid to insulin resistance as the key relevant pathosis, particularly insulin receptor signaling. However, many tissues play important roles in synergistically regulating metabolic homeostasis and should be considered part of a network. Our approach identifies redox as an acute regulator of the greater metabolic network. Redox reactions involve the transfer of electrons between two molecules and in this work refer to commonly shared molecules, reflective of energy state, that can readily lose electrons to increase or gain electrons to decrease the oxidation state of molecules including NAD(P), NAD(P)H, and thiols. Metabolism alters such redox molecules to impact metabolic function in many tissues, thus, responding to anabolic and catabolic stimuli appropriately and synergistically. It is also important to consider environmental factors that have arisen or increased in recent decades as putative modifiers of redox and reactive oxygen species (ROS) and thus metabolic state. ROS are highly reactive, controlled by the thiol redox state and influence the function of thousands of proteins. Lactate (L) and pyruvate (P) in cells are present in a ratio of about 10 reflective of the cytosolic NADH to NAD ratio. Equilibrium is maintained in cells because lactate dehydrogenase is highly expressed and near equilibrium. The major source of circulating lactate and pyruvate is muscle, although other tissues also contribute. Acetoacetate (A) is produced primarily by liver mitochondria where β-hydroxybutyrate dehydrogenase is highly expressed, and maintains a ratio of β-hydroxybutyrate (β) to A of about 2, reflective of the mitochondrial NADH to NAD ratio. All four metabolites as well as the thiols, cysteine and glutathione, are transported into and out of cells, due to high expression of relevant transporters. Our model supports regulation of all collaborating metabolic organs through changes in circulating redox metabolites, regardless of whether change was initiated exogenously or by a single organ. Validation of these predictions suggests novel ways to understand function by monitoring and impacting redox state.
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Affiliation(s)
- Barbara E. Corkey
- Department of Medicine, Boston University School of Medicine, Boston, MA, United States
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16
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Plecitá-Hlavatá L, Jabůrek M, Holendová B, Tauber J, Pavluch V, Berková Z, Cahová M, Schröder K, Brandes RP, Siemen D, Ježek P. Glucose-Stimulated Insulin Secretion Fundamentally Requires H 2O 2 Signaling by NADPH Oxidase 4. Diabetes 2020; 69:1341-1354. [PMID: 32245800 DOI: 10.2337/db19-1130] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 03/30/2020] [Indexed: 11/13/2022]
Abstract
NADPH facilitates glucose-stimulated insulin secretion (GSIS) in pancreatic islets (PIs) of β-cells through an as yet unknown mechanism. We found NADPH oxidase isoform 4 (NOX4) to be the main producer of cytosolic H2O2, which is essential for GSIS; an increase in ATP alone was insufficient for GSIS. The fast GSIS phase was absent from PIs from NOX4-null, β-cell-specific knockout mice (NOX4βKO) (though not from NOX2 knockout mice) and from NOX4-silenced or catalase-overexpressing INS-1E cells. Lentiviral NOX4 overexpression or H2O2 rescued GSIS in PIs from NOX4βKO mice. NOX4 silencing suppressed Ca2+ oscillations, and the patch-clamped KATP channel opened more frequently when glucose was high. Mitochondrial H2O2, decreasing upon GSIS, provided alternative redox signaling when 2-oxo-isocaproate or fatty acid oxidation formed superoxides through electron-transfer flavoprotein:Q-oxidoreductase. Unlike GSIS, such insulin secretion was blocked with mitochondrial antioxidant SkQ1. Both NOX4 knockout and NOX4βKO mice exhibited impaired glucose tolerance and peripheral insulin resistance. Thus, the redox signaling previously suggested to cause β-cells to self-check hypothetically induces insulin resistance when it is absent. In conclusion, increases in ATP and H2O2 constitute an essential signal that switches on insulin exocytosis for glucose and branched-chain oxoacids as secretagogues (it does so partially for fatty acids). Redox signaling could be impaired by cytosolic antioxidants; hence, those targeting mitochondria should be preferred for clinical applications to treat (pre)diabetes at any stage.
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Affiliation(s)
- Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Tauber
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vojtěch Pavluch
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Zuzana Berková
- Institute of Clinical and Experimental Medicine, Prague, Czech Republic
| | - Monika Cahová
- Institute of Clinical and Experimental Medicine, Prague, Czech Republic
| | - Katrin Schröder
- Institut für Kardiovaskuläre Physiologie, Goethe-Universität, Frankfurt, Germany
| | - Ralf P Brandes
- Institut für Kardiovaskuläre Physiologie, Goethe-Universität, Frankfurt, Germany
| | - Detlef Siemen
- Klinik für Neurologie, Universität Magdeburg, Magdeburg, Germany
| | - Petr Ježek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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17
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Las G, Oliveira MF, Shirihai OS. Emerging roles of β-cell mitochondria in type-2-diabetes. Mol Aspects Med 2020; 71:100843. [PMID: 31918997 DOI: 10.1016/j.mam.2019.100843] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/23/2019] [Accepted: 12/27/2019] [Indexed: 10/25/2022]
Abstract
Type-2-Diabetes (T2D) is the most common metabolic disease in the world today. It erupts as a result of peripheral insulin resistance combined with hyperinsulinemia followed by suppression of insulin secretion from pancreatic β-cells. Mitochondria play a central role in β-cells by sensing glucose and also by mediating the suppression of insulin secretion in T2D. Here, we will summarize the evidence accumulated for the roles of β-cells mitochondria in T2D. We will present an updated view on how mitochondria in β-cells have been associated with T2D, from the genetic, bioenergetic, redox and structural points of view. The emerging picture is that mitochondrial structure and dysfunction directly contribute to β-cell function and in the pathogenesis of T2D.
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Affiliation(s)
- Guy Las
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel
| | - Marcus F Oliveira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal Do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, Brazil.
| | - Orian S Shirihai
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
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18
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Kopp W. Development of Obesity: The Driver and the Passenger. Diabetes Metab Syndr Obes 2020; 13:4631-4642. [PMID: 33281458 PMCID: PMC7709141 DOI: 10.2147/dmso.s280146] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/03/2020] [Indexed: 12/16/2022] Open
Abstract
Obesity has reached epidemic proportions and is one of the greatest challenges for public health in the twenty-first century. The macronutrient composition of diets, in particular the amount and ratio of carbohydrates, fat and protein, have received considerable attention in recent decades due to its potential relevance to the development of obesity and weight loss. The effects of various macronutrients on body weight regulation are still under debate. High-carbohydrate diets, and particularly high-fat diets, have been blamed for the increase in the prevalence of obesity. This paper shows that neither fat nor carbohydrates are fattening per se. Mixed diets with substantial amounts of fat and high-glycemic carbohydrates, like current WDs, are required to promote weight gain and obesity. High-glycemic carbohydrates are the active partner (the "driver"), which promotes fat storage through its insulinogenic effect, while fat is the passive partner (the "passenger") on the way to obesity. Elevated insulin levels (postprandial, but more importantly due to hypersecretion and hyperinsulinemia) promote fat storage and play a key role in obesogenesis and the obesity epidemic. Furthermore, mixed diets high in high-glycemic carbohydrates and fat promote fetal programming, with long-term adverse impacts on the offspring, including insulin hypersecretion, (childhood) obesity and metabolic diseases. Maternal obesity and high weight gain during pregnancy have also been linked to deleterious effects on fetal programming. As the global obesity epidemic increasingly affects women of reproductive age, a significant percentage of fetuses will experience fetal programming with a tendency towards obesity - a self-reinforcing process that further fuels the epidemic. A change in lifestyle and diet composition is needed to prevent or limit the development of obesity and related diseases.
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Affiliation(s)
- Wolfgang Kopp
- Diagnostikzentrum Graz, Graz, 8043, Austria
- Correspondence: Wolfgang Kopp Former Head of Diagnostikzentrum (retired), Mariatrosterstraße 41, Graz8043, Austria Email
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19
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Zhu Y, Ren C, Zhang M, Zhong Y. Perilipin 5 Reduces Oxidative Damage Associated With Lipotoxicity by Activating the PI3K/ERK-Mediated Nrf2-ARE Signaling Pathway in INS-1 Pancreatic β-Cells. Front Endocrinol (Lausanne) 2020; 11:166. [PMID: 32296390 PMCID: PMC7136399 DOI: 10.3389/fendo.2020.00166] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/09/2020] [Indexed: 12/16/2022] Open
Abstract
Oxidative stress induced by free fatty acid overload in pancreatic β-cells is a potential contributory factor to dysfunction of insulin secretion and apoptotic cell death. Perilipin 5 (Plin5) has been reported to ameliorate oxidative stress-mediated damage in non-insulin-secreting tissues. We tested the hypothesis that Plin5 plays a similar role in pancreatic β-cells, which are extremely sensitive to oxidative stress. Here, our in vitro data showed that Plin5-mediated alleviation of palmitate-triggered apoptosis involves the mitochondrial pathway. And the protective role of Plin5 on β-cells was partially dependent on its modulation in oxidative stress. Upregulation of Plin5 in INS-1 cells decreased reactive oxygen species production, enhanced cellular glutathione levels, and induced expression of antioxidant enzymes glutamate-cysteine ligase catalytic subunit and heme oxygenase-1. However, knocking out of Plin5 abolished all of these beneficial effects. Furthermore, by using the O2- scavenger MnTMPyP, we verified that altering Plin5 expression impacted lipotoxic cell death partially via modulating oxidative stress. Mechanistic experiments revealed that Plin5 induced Nrf2-ARE system, a master regulator in the cellular adaptive response to oxidative stress, by activating PI3K/Akt and ERK signal pathways, contributing to the increase of antioxidant defense and consequently improving β-cell function and survival in the presence of lipotoxic oxidative stress. Overall, our findings indicate that Plin5 abrogates oxidative damage in INS-1 β-cells during lipotoxic stress partially through the enhancement of antioxidant defense involving the PI3K/Akt and ERK mediated Nrf2-ARE system.
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Affiliation(s)
- Yunxia Zhu
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- *Correspondence: Yunxia Zhu
| | - Chenxi Ren
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Mingliang Zhang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Yuan Zhong
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
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20
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Roma LP, Jonas JC. Nutrient Metabolism, Subcellular Redox State, and Oxidative Stress in Pancreatic Islets and β-Cells. J Mol Biol 2019; 432:1461-1493. [PMID: 31634466 DOI: 10.1016/j.jmb.2019.10.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/25/2019] [Accepted: 10/10/2019] [Indexed: 01/01/2023]
Abstract
Insulin-secreting pancreatic β-cells play a critical role in blood glucose homeostasis and the development of type 2 diabetes (T2D) in the context of insulin resistance. Based on data obtained at the whole cell level using poorly specific chemical probes, reactive oxygen species (ROS) such as superoxide and hydrogen peroxide have been proposed to contribute to the stimulation of insulin secretion by nutrients (positive role) and to the alterations of cell survival and secretory function in T2D (negative role). This raised the controversial hypothesis that any attempt to decrease β-cell oxidative stress and apoptosis in T2D would further impair insulin secretion. Over the last decade, the development of genetically-encoded redox probes that can be targeted to cellular compartments of interest and are specific of redox couples allowed the evaluation of short- and long-term effects of nutrients on β-cell redox changes at the subcellular level. The data indicated that the nutrient regulation of β-cell redox signaling and ROS toxicity is far more complex than previously thought and that the subcellular compartmentation of these processes cannot be neglected when evaluating the mechanisms of ROS production or the efficacy of antioxidant enzymes and antioxidant drugs under glucolipotoxic conditions and in T2D. In this review, we present what is currently known about the compartmentation of redox homeostatic systems and tools to investigate it. We then review data about the effects of nutrients on β-cell subcellular redox state under normal conditions and in the context of T2D and discuss challenges and opportunities in the field.
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Affiliation(s)
- Leticia P Roma
- Universität des Saarlandes, Biophysics Department, Center for Human and Molecular Biology, Kirbergerstrasse Building 48, 66421, Homburg/Saar, Germany
| | - Jean-Christophe Jonas
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, Avenue Hippocrate 55 (B1.55.06), B-1200 Brussels, Belgium.
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21
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Ježek P, Jabůrek M, Plecitá-Hlavatá L. Contribution of Oxidative Stress and Impaired Biogenesis of Pancreatic β-Cells to Type 2 Diabetes. Antioxid Redox Signal 2019; 31:722-751. [PMID: 30450940 PMCID: PMC6708273 DOI: 10.1089/ars.2018.7656] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/05/2018] [Indexed: 12/14/2022]
Abstract
Significance: Type 2 diabetes development involves multiple changes in β-cells, related to the oxidative stress and impaired redox signaling, beginning frequently by sustained overfeeding due to the resulting lipotoxicity and glucotoxicity. Uncovering relationships among the dysregulated metabolism, impaired β-cell "well-being," biogenesis, or cross talk with peripheral insulin resistance is required for elucidation of type 2 diabetes etiology. Recent Advances: It has been recognized that the oxidative stress, lipotoxicity, and glucotoxicity cannot be separated from numerous other cell pathology events, such as the attempted compensation of β-cell for the increased insulin demand and dynamics of β-cell biogenesis and its "reversal" at dedifferentiation, that is, from the concomitantly decreasing islet β-cell mass (also due to transdifferentiation) and low-grade islet or systemic inflammation. Critical Issues: At prediabetes, the compensation responses of β-cells, attempting to delay the pathology progression-when exaggerated-set a new state, in which a self-checking redox signaling related to the expression of Ins gene expression is impaired. The resulting altered redox signaling, diminished insulin secretion responses to various secretagogues including glucose, may lead to excretion of cytokines or chemokines by β-cells or excretion of endosomes. They could substantiate putative stress signals to the periphery. Subsequent changes and lasting glucolipotoxicity promote islet inflammatory responses and further pathology spiral. Future Directions: Should bring an understanding of the β-cell self-checking and related redox signaling, including the putative stress signal to periphery. Strategies to cure or prevent type 2 diabetes could be based on the substitution of the "wrong" signal by the "correct" self-checking signal.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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22
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Mishra JS, More AS, Kumar S. Elevated androgen levels induce hyperinsulinemia through increase in Ins1 transcription in pancreatic beta cells in female rats. Biol Reprod 2019; 98:520-531. [PMID: 29365042 DOI: 10.1093/biolre/ioy017] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/19/2018] [Indexed: 12/15/2022] Open
Abstract
Hyperandrogenism is associated with hyperinsulinemia and insulin resistance in adult females. We tested whether androgens dysregulate pancreatic beta cell function to induce hyperinsulinemia through transcriptional regulation of insulin gene (Ins) in the islets. Adult female Wistar rats implanted with dihydrotestosterone (DHT; 7.5-mg, 90-d release) or placebo pellets were examined after 10 weeks. DHT exposure increased plasma DHT levels by 2-fold similar to that in polycystic ovary syndrome in women. DHT exposure induced hyperinsulinemia with increased HOMA-IR index in fasting state and glucose intolerance and exaggerated insulin responses following glucose tolerance test. DHT females had no change in islet number, size and beta cell proliferation/apoptosis but exhibited significant mitochondrial dysfunction (higher ADP/ATP ratio, decreased mtDNA copy number, increased reactive oxygen production and downregulation of mitochondrial biogenesis) and enhanced glucose-stimulated insulin secretion. Ins expression was increased in DHT islets. In vitro incubation of control islets with DHT dose dependently stimulated Ins transcription. Analysis of Ins1 gene revealed a putative androgen responsive element in the promoter. Chromatin-immunoprecipitation assays showed that androgen receptors bind to this element in response to DHT stimulation. Furthermore, reporter assays showed that the promoter element is highly responsive to androgens. Insulin-stimulated glucose uptake in skeletal muscle was decreased with associated decrease in IRβ expression in DHT females. Our studies identified a novel androgen-mediated mechanism for the control of Ins expression via transcriptional regulation providing a molecular mechanism linking elevated androgens and hyperinsulemia. Decreased IRβ expression in the skeletal muscles may contribute, in part, to glucose intolerance in this model.
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Affiliation(s)
- Jay S Mishra
- Department of Comparative Biosciences and Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amar S More
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Sathish Kumar
- Department of Comparative Biosciences and Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Thomas DD, Corkey BE, Istfan NW, Apovian CM. Hyperinsulinemia: An Early Indicator of Metabolic Dysfunction. J Endocr Soc 2019; 3:1727-1747. [PMID: 31528832 PMCID: PMC6735759 DOI: 10.1210/js.2019-00065] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/18/2019] [Indexed: 02/06/2023] Open
Abstract
Hyperinsulinemia is strongly associated with type 2 diabetes. Racial and ethnic minority populations are disproportionately affected by diabetes and obesity-related complications. This mini-review provides an overview of the genetic and environmental factors associated with hyperinsulinemia with a focus on racial and ethnic differences and its metabolic consequences. The data used in this narrative review were collected through research in PubMed and reference review of relevant retrieved articles. Insulin secretion and clearance are regulated processes that influence the development and progression of hyperinsulinemia. Environmental, genetic, and dietary factors are associated with hyperinsulinemia. Certain pharmacotherapies for obesity and bariatric surgery are effective at mitigating hyperinsulinemia and are associated with improved metabolic health. Hyperinsulinemia is associated with many environmental and genetic factors that interact with a wide network of hormones. Recent studies have advanced our understanding of the factors affecting insulin secretion and clearance. Further basic and translational work on hyperinsulinemia may allow for earlier and more personalized treatments for obesity and metabolic diseases.
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Affiliation(s)
- Dylan D Thomas
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
| | - Barbara E Corkey
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
| | - Nawfal W Istfan
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
| | - Caroline M Apovian
- Department of Medicine, Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
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Synergic effects of oxygen supply and antioxidants on pancreatic β-cell spheroids. Sci Rep 2019; 9:1802. [PMID: 30755634 PMCID: PMC6372787 DOI: 10.1038/s41598-018-38011-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/12/2018] [Indexed: 12/14/2022] Open
Abstract
Diabetes is one of the most common metabolic disorders, and is characterized by the inability to secrete/sense insulin and abnormal blood glucose concentration. Many researchers have concentrated their efforts on improving islet transplantation, in particular by fabricating bioartificial pancreatic islets in vitro. One of the critical points for the success of this research direction is the improvement of culture conditions, such as oxygen supply, in the engineering of bioartificial pancreatic islets to ensure their viability and functionality after transplantation. In this work, we fabricated microwell spheroid culture devices made of oxygen-permeable polydimethylsiloxane (PDMS), with which hypoxia in the core of bioartificial islets was alleviated and glucose-stimulated insulin secretion was increased ~2.5-fold compared to a device with the same configuration but made of non-oxygen-permeable plastic. We also demonstrated that antioxidants, such as ascorbic acid-2-phosphate (AA2P), could neutralize islet damage caused by increased reactive oxygen species (ROS) in the cell culture environment. These results suggest that supply of oxygen together with removal of ROS may lead to a better approach to prepare highly viable and functional bioartificial pancreatic islets.
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Kopp W. How Western Diet And Lifestyle Drive The Pandemic Of Obesity And Civilization Diseases. Diabetes Metab Syndr Obes 2019; 12:2221-2236. [PMID: 31695465 PMCID: PMC6817492 DOI: 10.2147/dmso.s216791] [Citation(s) in RCA: 347] [Impact Index Per Article: 69.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/13/2019] [Indexed: 12/12/2022] Open
Abstract
Westernized populations are plagued by a plethora of chronic non-infectious degenerative diseases, termed as "civilization diseases", like obesity, diabetes, cardiovascular diseases, cancer, autoimmune diseases, Alzheimer's disease and many more, diseases which are rare or virtually absent in hunter-gatherers and other non-westernized populations. There is a growing awareness that the cause of this amazing discrepancy lies in the profound changes in diet and lifestyle during recent human history. This paper shows that the transition from Paleolithic nutrition to Western diets, along with lack of corresponding genetic adaptations, cause significant distortions of the fine-tuned metabolism that has evolved over millions of years of human evolution in adaptation to Paleolithic diets. With the increasing spread of Western diet and lifestyle worldwide, overweight and civilization diseases are also rapidly increasing in developing countries. It is suggested that the diet-related key changes in the developmental process include an increased production of reactive oxygen species and oxidative stress, development of hyperinsulinemia and insulin resistance, low-grade inflammation and an abnormal activation of the sympathetic nervous system and the renin-angiotensin system, all of which play pivotal roles in the development of diseases of civilization. In addition, diet-related epigenetic changes and fetal programming play an important role. The suggested pathomechanism is also able to explain the well-known but not completely understood close relationship between obesity and the wide range of comorbidities, like type 2 diabetes mellitus, cardiovascular disease, etc., as diseases of the same etiopathology. Changing our lifestyle in accordance with our genetic makeup, including diet and physical activity, may help prevent or limit the development of these diseases.
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Affiliation(s)
- Wolfgang Kopp
- Retired Head, Diagnostikzentrum Graz, Graz8043, Austria
- Correspondence: Wolfgang Kopp Mariatrosterstraße 41, Graz8043, Austria Email
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High dose of histone deacetylase inhibitors affects insulin secretory mechanism of pancreatic beta cell line. Endocr Regul 2018; 52:21-26. [DOI: 10.2478/enr-2018-0004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Abstract
Objective. Histone deacytylase inhibitors (HDACis) inhibit the deacetylation of the lysine residue of proteins, including histones, and regulate the transcription of a variety of genes. Recently, HDACis have been used clinically as anti-cancer drugs and possible anti-diabetic drugs. Even though HDACis have been proven to protect the cytokine-induced damage of pancreatic beta cells, evidence also shows that high doses of HDACis are cytotoxic. In the present study, we, therefore, investigated the eff ect of HDACis on insulin secretion in a pancreatic beta cell line. Methods. Pancreatic beta cells MIN6 were treated with selected HDACis (trichostatin A, TSA; valproic acid, VPA; and sodium butyrate, NaB) in medium supplemented with 25 mM glucose and 13% heat-inactivated fetal bovine serum (FBS) for indicated time intervals. Protein expression of Pdx1 and Mafa in MIN6 cells was demonstrated by immunohistochemistry and immunocytochemistry, expression of Pdx1 and Mafa genes was measured by quantitative RT-PCR method. Insulin release from MIN6 cells and insulin cell content were estimated by ELISA kit. Superoxide production in MIN6 cells was measured using a Total ROS/Superoxide Detection System. Results. TSA, VPA, and NaB inhibited the expression of Pdx1 and Mafa genes and their products. TSA treatment led to beta cell malfunction, characterized by enhanced insulin secretion at 3 and 9 mM glucose, but impaired insulin secretion at 15 and 25 mM glucose. Th us, TSA induced dysregulation of the insulin secretion mechanism. TSA also enhanced reactive oxygen species production in pancreatic beta cells. Conclusions. Our results showed that HDACis caused failure to suppress insulin secretion at low glucose concentrations and enhance insulin secretion at high glucose concentrations. In other words, when these HDACis are used clinically, high doses of HDACis may cause hypoglycemia in the fasting state and hyperglycemia in the fed state. When using HDACis, physicians should, therefore, be aware of the capacity of these drugs to modulate the insulin secretory capacity of pancreatic beta cells.
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Lipko M, Debski B. Mechanism of insulin-like effect of chromium(III) ions on glucose uptake in C2C12 mouse myotubes involves ROS formation. J Trace Elem Med Biol 2018; 45:171-175. [PMID: 29173475 DOI: 10.1016/j.jtemb.2017.10.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/19/2017] [Accepted: 10/27/2017] [Indexed: 11/26/2022]
Abstract
Chromium is considered a trace element which improves glucose tolerance, but mechanism accounting for this insulin-like action is not recognized. The main purpose of this study was to examine the role of reactive oxygen species (ROS) in chromium and insulin stimulated glucose transport using antioxidants. Effect of chromium ions on phosphatases, enzymes involved in inhibition of insulin signaling was also investigated. Experiments were performed in vitro on C2C12 mouse myotubes. ROS level was measured with the use of confocal microscope and 2',7' dichlorodihydrofluorescein diacetate (DCFH-DA). Glucose metabolism was assayed by the measurement of 2-[3H]-deoxyglucose uptake. Cr3+ ions and insulin treatment caused significant increase of ROS formation and also stimulated glucose uptake in C2C12 cells in concentration dependent manner. Antioxidants (L-ascorbic acid and N-acetyl cysteine 100μM) and DPI (diphenyleneiodonium-NADPH oxidase inhibitor, 10μM) abolished insulin- and Cr-inducted glucose transport. Our results confirm the hypothesis that the ROS are integral part of insulin signaling pathway and that the insulin mimetic effect of Cr3+ ions depends on the antioxidant status of the cells. Surprisingly, chromium treatment resulted in increased activity of membrane phosphatases.
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Affiliation(s)
- Maciej Lipko
- Department of Physiological Science, Faculty of Veterinary Medicine, Warsaw Agricultural University, Poland.
| | - Bogdan Debski
- Department of Physiological Science, Faculty of Veterinary Medicine, Warsaw Agricultural University, Poland
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Jones IV AR, Coleman EL, Husni NR, Deeney JT, Raval F, Steenkamp D, Dooms H, Nikolajczyk BS, Corkey BE. Type 1 diabetes alters lipid handling and metabolism in human fibroblasts and peripheral blood mononuclear cells. PLoS One 2017; 12:e0188474. [PMID: 29206239 PMCID: PMC5714353 DOI: 10.1371/journal.pone.0188474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 11/07/2017] [Indexed: 01/05/2023] Open
Abstract
Triggers of the autoimmune response that leads to type 1 diabetes (T1D) remain poorly understood. A possibility is that parallel changes in both T cells and target cells provoke autoimmune attack. We previously documented greater Ca2+ transients in fibroblasts from T1D subjects than non-T1D after exposure to fatty acids (FA) and tumor necrosis factor α (TNFα). These data indicate that metabolic and signal transduction defects present in T1D can be elicited ex vivo in isolated cells. Changes that precede T1D, including inflammation, may activate atypical responses in people that are genetically predisposed to T1D. To identify such cellular differences in T1D, we quantified a panel of metabolic responses in fibroblasts and peripheral blood cells (PBMCs) from age-matched T1D and non-T1D subjects, as models for non-immune and immune cells, respectively. Fibroblasts from T1D subjects accumulated more lipid, had higher LC-CoA levels and converted more FA to CO2, with less mitochondrial proton leak in response to oleate alone or with TNFα, using the latter as a model of inflammation. T1D-PBMCs contained and also accumulated more lipid following FA exposure. In addition, they formed more peroxidized lipid than controls following FA exposure. We conclude that both immune and non-immune cells in T1D subjects differ from controls in terms of responses to FA and TNFα. Our results suggest a differential sensitivity to inflammatory insults and FA that may precede and contribute to T1D by priming both immune cells and their targets for autoimmune reactions.
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Affiliation(s)
- Albert R. Jones IV
- Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA, United States of America
| | - Emily L. Coleman
- Yale University School of Medicine, New Haven, CT, United States of America
| | - Nicholas R. Husni
- Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA, United States of America
| | - Jude T. Deeney
- Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA, United States of America
| | - Forum Raval
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America
| | - Devin Steenkamp
- Endocrinology Section, Evans Department of Medicine, Boston University School of Medicine, Boston, MA, United States of America
| | - Hans Dooms
- Rheumatology Section, Evans Department of Medicine, Boston University School of Medicine, Boston, MA, United States of America
| | - Barbara S. Nikolajczyk
- Department of Translational Research in Diabetes, University of Kentucky School of Medicine, Lexington, KY, United States of America
- Department of Pharmacology and Nutritional Sciences, University of Kentucky School of Medicine, Lexington, KY, United States of America
| | - Barbara E. Corkey
- Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA, United States of America
- * E-mail:
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29
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Mihailidou C, Chatzistamou I, Papavassiliou AG, Kiaris H. Modulation of Pancreatic Islets' Function and Survival During Aging Involves the Differential Regulation of Endoplasmic Reticulum Stress by p21 and CHOP. Antioxid Redox Signal 2017; 27:185-200. [PMID: 27931122 PMCID: PMC5512329 DOI: 10.1089/ars.2016.6671] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIMS Although endoplasmic reticulum (ER) stress is recognized as a major mechanism causing pancreatic dysfunction in diabetes, little is known on how aging modulates the process. Here, we compared the response with ER stress, viability, and insulin release from pancreatic islets of young (6 weeks) or aged (14 months) mice. RESULTS Islets from aged mice were more sensitive to ER stress than their younger counterparts; they exhibited more pronounced unfolded protein response (UPR) and caspase activation and displayed compromised insulin release after high-glucose stimulation. Genetic ablation of p21 sensitized the islets to ER stress, especially in the aged group, whereas CHOP ablation was protective for islets from both aged and younger animals. Ciclopirox (CPX), an iron chelator that stimulates p21 expression, protected islets from glucotoxicity and mice from diet-induced diabetes, especially in the aged group in a manner that was both p21 and CHOP dependent. INNOVATION For the first time, the study shows that age-dependent susceptibility to diet-induced diabetes is associated with the activity of p21 and CHOP in pancreatic islets and that CPX protects islets from glucotoxicity and mice from diabetes in an age-dependent manner. CONCLUSIONS Our results identify ER stress as an age-dependent modifier of islet survival and function by mechanisms implicating enhancement of CHOP activity and inhibition of the protective activity of p21. These findings suggest that interventions restoring the homeostatic activity of ER stress, by agents such as CPX, may be particularly beneficial for the management of diabetes in the elderly. Antioxid. Redox Signal. 27, 185-200.
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Affiliation(s)
- Chrysovalantou Mihailidou
- 1 Department of Biological Chemistry, National and Kapodistrian University of Athens , Medical School, Athens, Greece
| | - Ioulia Chatzistamou
- 2 Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine , Columbia, South Carolina
| | - Athanasios G Papavassiliou
- 1 Department of Biological Chemistry, National and Kapodistrian University of Athens , Medical School, Athens, Greece
| | - Hippokratis Kiaris
- 1 Department of Biological Chemistry, National and Kapodistrian University of Athens , Medical School, Athens, Greece .,3 Department of Drug Discovery and Biomedical Sciences, University of South Carolina , Columbia, South Carolina
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De Marchi U, Hermant A, Thevenet J, Ratinaud Y, Santo-Domingo J, Barron D, Wiederkehr A. A novel ATP-synthase-independent mechanism coupling mitochondrial activation to exocytosis in insulin-secreting cells. J Cell Sci 2017; 130:1929-1939. [PMID: 28404787 DOI: 10.1242/jcs.200741] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 04/11/2017] [Indexed: 12/16/2022] Open
Abstract
Pancreatic β-cells sense glucose, promoting insulin secretion. Glucose sensing requires the sequential stimulation of glycolysis, mitochondrial metabolism and Ca2+ entry. To elucidate how mitochondrial activation in β-cells contributes to insulin secretion, we compared the effects of glucose and the mitochondrial substrate methylsuccinate in the INS-1E insulin-secreting cell line at the respective concentrations at which they maximally activate mitochondrial respiration. Both substrates induced insulin secretion with distinct respiratory profiles, mitochondrial hyperpolarization, NADH production and ATP-to-ADP ratios. In contrast to glucose, methylsuccinate failed to induce large [Ca2+] rises and exocytosis proceeded largely independently of mitochondrial ATP synthesis. Both glucose- and methylsuccinate-induced secretion was blocked by diazoxide, indicating that Ca2+ is required for exocytosis. Dynamic assessment of the redox state of mitochondrial thiols revealed a less marked reduction in response to methylsuccinate than with glucose. Our results demonstrate that insulin exocytosis can be promoted by two distinct mechanisms one of which is dependent on mitochondrial ATP synthesis and large Ca2+ transients, and one of which is independent of mitochondrial ATP synthesis and relies on small Ca2+ signals. We propose that the combined effects of Ca2+ and redox reactions can trigger insulin secretion by these two mechanisms.
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Affiliation(s)
- Umberto De Marchi
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Aurelie Hermant
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Jonathan Thevenet
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Yann Ratinaud
- Natural Bioactives and screening, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building H, Lausanne CH-1015, Switzerland
| | - Jaime Santo-Domingo
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Denis Barron
- Natural Bioactives and screening, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building H, Lausanne CH-1015, Switzerland
| | - Andreas Wiederkehr
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
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Hsu MC, Wang ME, Jiang YF, Liu HC, Chen YC, Chiu CH. Long-term feeding of high-fat plus high-fructose diet induces isolated impaired glucose tolerance and skeletal muscle insulin resistance in miniature pigs. Diabetol Metab Syndr 2017; 9:81. [PMID: 29046729 PMCID: PMC5640912 DOI: 10.1186/s13098-017-0281-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 10/06/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND During the prediabetic development, the changes in β-cell function and tissue-specific insulin resistance have been described. However, there are conflicting views in insulin secretory capacity between early clinical observation and recent proposed mathematical model. On the basis of digestive and metabolic similarities with humans, swine have great potential as an animal model to investigate the progressive mechanisms of prediabetes. The aim of this study was to investigate the insulin secretory response and tissue-specific insulin resistance in a dietary-induced prediabetic porcine model. METHODS Adult male Taiwan Lee-Sung miniature pigs were randomized into two groups: (1) low-fat diet and (2) high-fat plus high-fructose diet (HFHF; 20.9% crude fat and 17.8% fructose). During the 12-month dietary intervention, body weights and blood glucose levels were measured monthly. Intravenous glucose tolerance test was used for measuring glucose tolerance and insulin secretory capacity. At the end of the experiment, liver and soleus muscle specimens were collected for ex vivo insulin sensitivity testing. RESULTS The results showed that the HFHF group had obesity, hyperinsulinemia, and dyslipidemia, but normal fasting glucose levels. The HFHF pigs exhibited enhanced first- and second-phase insulin secretion and high 2-h postload glucose levels in intravenous glucose tolerance test. Furthermore, the skeletal muscle specimens from the HFHF group were desensitized to insulin stimulation as shown by the lack of AKT Ser473 phosphorylation; however, the liver specimens remained a normal response. CONCLUSIONS In conclusion, the HFHF diet-fed pigs developed isolated impaired glucose tolerance corresponding to prediabetes with an intense insulin secretory response and skeletal muscle insulin resistance.
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Affiliation(s)
- Meng-Chieh Hsu
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, No. 50, Ln. 155, Sec. 3, Keelung Rd., Da’an Dist., Taipei, 106 Taiwan, Republic of China
| | - Mu-En Wang
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, No. 50, Ln. 155, Sec. 3, Keelung Rd., Da’an Dist., Taipei, 106 Taiwan, Republic of China
| | - Yi-Fan Jiang
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, No. 50, Ln. 155, Sec. 3, Keelung Rd., Da’an Dist., Taipei, 106 Taiwan, Republic of China
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, No. 1, Sec. 4, Rooservelt Rd., Da’an Dist., Taipei, 106 Taiwan, Republic of China
| | - Hung-Chang Liu
- Department of Thoracic Surgery, Mackay Memorial Hospital, No. 92, Sec. 2, Chung-Shan North Rd., Zhongshan Dist., Taipei, 104 Taiwan, Republic of China
| | - Yi-Chen Chen
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, No. 50, Ln. 155, Sec. 3, Keelung Rd., Da’an Dist., Taipei, 106 Taiwan, Republic of China
| | - Chih-Hsien Chiu
- Laboratory of Animal Physiology, Department of Animal Science and Technology, National Taiwan University, No. 50, Ln. 155, Sec. 3, Keelung Rd., Da’an Dist., Taipei, 106 Taiwan, Republic of China
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David JA, Rifkin WJ, Rabbani PS, Ceradini DJ. The Nrf2/Keap1/ARE Pathway and Oxidative Stress as a Therapeutic Target in Type II Diabetes Mellitus. J Diabetes Res 2017; 2017:4826724. [PMID: 28913364 PMCID: PMC5585663 DOI: 10.1155/2017/4826724] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/03/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
Despite improvements in awareness and treatment of type II diabetes mellitus (TIIDM), this disease remains a major source of morbidity and mortality worldwide, and prevalence continues to rise. Oxidative damage caused by free radicals has long been known to contribute to the pathogenesis and progression of TIIDM and its complications. Only recently, however, has the role of the Nrf2/Keap1/ARE master antioxidant pathway in diabetic dysfunction begun to be elucidated. There is accumulating evidence that this pathway is implicated in diabetic damage to the pancreas, heart, and skin, among other cell types and tissues. Animal studies and clinical trials have shown promising results suggesting that activation of this pathway can delay or reverse some of these impairments in TIIDM. In this review, we outline the role of oxidative damage and the Nrf2/Keap1/ARE pathway in TIIDM, focusing on current and future efforts to utilize this relationship as a therapeutic target for prevention, prognosis, and treatment of TIID.
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Affiliation(s)
- Joshua A. David
- Hansjörg Wyss Department of Plastic and Reconstructive Surgery, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA
| | - William J. Rifkin
- Hansjörg Wyss Department of Plastic and Reconstructive Surgery, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA
| | - Piul S. Rabbani
- Hansjörg Wyss Department of Plastic and Reconstructive Surgery, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA
| | - Daniel J. Ceradini
- Hansjörg Wyss Department of Plastic and Reconstructive Surgery, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA
- *Daniel J. Ceradini:
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Fu J, Cui Q, Yang B, Hou Y, Wang H, Xu Y, Wang D, Zhang Q, Pi J. The impairment of glucose-stimulated insulin secretion in pancreatic β-cells caused by prolonged glucotoxicity and lipotoxicity is associated with elevated adaptive antioxidant response. Food Chem Toxicol 2016; 100:161-167. [PMID: 28027979 DOI: 10.1016/j.fct.2016.12.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/06/2016] [Accepted: 12/14/2016] [Indexed: 11/17/2022]
Abstract
Type 2 diabetes (T2D) is a progressive disease characterized by sustained hyperglycemia and is frequently accompanied by hyperlipidemia. Deterioration of β-cell function in T2D patients may be caused, in part, by long-term exposure to high concentrations of glucose and/or lipids. We developed systems to study how chronic glucotoxicity and lipotoxicity might be linked to the impairment of glucose-stimulated insulin secretion (GSIS) machinery in pancreatic β-cells. INS-1 (832/13) were exposed to glucose and/or palmitate for up to 10 weeks. Chronic high glucose and/or palmitate exposure resulted in impaired GSIS accompanied by a dramatic increase in oxidative stress, as determined by basal intracellular peroxide levels. In addition, the GSIS-associated reactive oxygen species (ROS) signals, assessed as glucose-stimulated peroxide accumulation positively correlated with GSIS in glucose- and/or palmitate-exposed cells, as well as glucose-stimulated reductions in GSH/GSSG ratios. Furthermore, the impairment of GSIS caused by chronic high glucose and/or palmitate exposures were attributed to the induction of adaptive antioxidant response and mitochondrial uncoupling, which negatively regulates glucose-derived ROS generation. Taken together, persistent glucotoxicity- and/or lipotoxicity-mediated oxidative stress and subsequent adaptive antioxidant response impair glucose-derived ROS signaling and GSIS in pancreatic β-cells.
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Affiliation(s)
- Jingqi Fu
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Qi Cui
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Bei Yang
- Department of Histology and Embryology, School of Basic Medical Sciences, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Yongyong Hou
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Huihui Wang
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Yuanyuan Xu
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Difei Wang
- The First Affiliated Hospital, China Medical University, 155 Nanjingbei Street, Heping District, Shenyang, Liaoning, 110001, PR China
| | - Qiang Zhang
- Department of Environmental Health, Rollins School of Public Health, Emory University, 201 Dowman Drive, Atlanta, GA, 30322, USA
| | - Jingbo Pi
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China.
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Ciclopirox enhances pancreatic islet health by modulating the unfolded protein response in diabetes. Pflugers Arch 2016; 468:1957-1968. [PMID: 27757583 DOI: 10.1007/s00424-016-1887-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/21/2016] [Accepted: 09/27/2016] [Indexed: 10/20/2022]
Abstract
Pancreatic dysfunction during diabetes is linked to the induction of endoplasmic reticulum (ER) stress on pancreatic beta (β) cells. Our laboratory recently discovered that p21 protects from diabetes by modifying the outcome of ER stress response. In the present study, we explored the antidiabetic activity of ciclopirox (CPX), an iron chelator and recently described activator of p21 expression. The effects of CPX in beta cell survival and function were assessed in cultured islets in vitro as well as in diabetic mice in vivo. The consequences of CPX in high glucose-induced insulin release and reactive oxygen species (ROS) production were also evaluated. Islet survival assays confirmed the significance of p21 in the regulation of glucotoxicity and suggested that CPX counteracts glucotoxicity in a manner that depends on p21. In vivo, administration of CPX in wild-type (WT) diabetic mice restored glucose homeostasis. In WT-cultured islets, CPX suppressed the expression of ER stress markers BiP, GRP94, and CHOP and reduced the levels of ROS during culture at high glucose. This reduction of ER stress may be associated with the ability of CPX to inhibit insulin release. Iron citrate stimulated insulin release, which was inhibited by CPX that functions as an iron chelator. It is conceivable that inhibition of insulin production constrains ER stress in islets promoting their survival and thus protecting from diabetes in vivo. This unfolded protein response (UPR)-antagonizing activity of CPX suggests application for the management not only of diabetes but also of other conditions related to ER stress.
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Jones IV AR, Meshulam T, Oliveira MF, Burritt N, Corkey BE. Extracellular Redox Regulation of Intracellular Reactive Oxygen Generation, Mitochondrial Function and Lipid Turnover in Cultured Human Adipocytes. PLoS One 2016; 11:e0164011. [PMID: 27741233 PMCID: PMC5065187 DOI: 10.1371/journal.pone.0164011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 09/19/2016] [Indexed: 12/04/2022] Open
Abstract
Background Many tissues play an important role in metabolic homeostasis and the development of diabetes and obesity. We hypothesized that the circulating redox metabolome is a master metabolic regulatory system that impacts all organs and modulates reactive oxygen species (ROS) production, lipid peroxidation, energy production and changes in lipid turnover in many cells including adipocytes. Methods Differentiated human preadipocytes were exposed to the redox couples, lactate (L) and pyruvate (P), β–hydroxybutyrate (βOHB) and acetoacetate (Acoc), and the thiol-disulfides cysteine/ cystine (Cys/CySS) and GSH/GSSG for 1.5–4 hours. ROS measurements were done with CM-H2DCFDA. Lipid peroxidation (LPO) was assessed by a modification of the thiobarbituric acid method. Lipolysis was measured as glycerol release. Lipid synthesis was measured as 14C-glucose incorporated into lipid. Respiration was assessed using the SeaHorse XF24 analyzer and the proton leak was determined from the difference in respiration with oligomycin and antimycin A. Results Metabolites with increasing oxidation potentials (GSSG, CySS, Acoc) increased adipocyte ROS. In contrast, P caused a decrease in ROS compared with L. Acoc also induced a significant increase in both LPO and lipid synthesis. L and Acoc increased lipolysis. βOHB increased respiration, mainly due to an increased proton leak. GSSG, when present throughout 14 days of differentiation significantly increased fat accumulation, but not when added later. Conclusions We demonstrated that in human adipocytes changes in the external redox state impacted ROS production, LPO, energy efficiency, lipid handling, and differentiation. A more oxidized state generally led to increased ROS, LPO and lipid turnover and more reduction led to increased respiration and a proton leak. However, not all of the redox couples were the same suggesting compartmentalization. These data are consistent with the concept of the circulating redox metabolome as a master metabolic regulatory system.
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Affiliation(s)
- Albert R. Jones IV
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Tova Meshulam
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Marcus F. Oliveira
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil
| | - Nathan Burritt
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Barbara E. Corkey
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Plecitá-Hlavatá L, Ježek P. Integration of superoxide formation and cristae morphology for mitochondrial redox signaling. Int J Biochem Cell Biol 2016; 80:31-50. [PMID: 27640755 DOI: 10.1016/j.biocel.2016.09.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 12/16/2022]
Abstract
The mitochondrial network provides the central cell's energetic and regulatory unit, which besides ATP and metabolite production participates in cellular signaling through regulated reactive oxygen species (ROS) production and various protein/ion fluxes. The inner membrane forms extensive folds, called cristae, i.e. cavities enfolded from and situated perpendicularly to its inner boundary membrane portion, which encompasses an inner cylinder within the outer membrane tubule. Mitochondrial cristae ultramorphology reflects various metabolic, physiological or pathological states. Since the mitochondrion is typically a predominant superoxide source and generated ROS also serve for the creation of information redox signals, we review known relationships between ROS generation within the respiratory chain complexes of cristae and cristae morphology. Notably, it is emphasized that cristae shape is governed by ATP-synthase dimers, MICOS complexes, OPA1 isoforms and the umbrella of their regulation, and also dependent on local protonmotive force (electrical potential component) in cristae. Cristae are also affected by redox-sensitive kinases/phosphatases or p66SHC. ATP-synthase dimers decrease in the inflated intracristal space, diminishing pH and hypothetically having minimal superoxide formation. Matrix-released signaling superoxide/H2O2 is predominantly integrated along mitochondrial tubules, whereas the diffusion of intracristal signaling ROS species is controlled by crista junctions, the widening of which enables specific retrograde redox signaling such as during hypoxic cell adaptation. Other physiological cases of H2O2 release from the mitochondrion include the modulation of insulin release in pancreatic β-cells, enhancement of insulin signaling in peripheral tissues, signaling by T-cell receptors, retrograde signaling during the cell cycle and cell differentiation, specifically that of adipocytes.
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Affiliation(s)
- Lydie Plecitá-Hlavatá
- Department of Membrane Transport Biophysics, No.75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Petr Ježek
- Department of Membrane Transport Biophysics, No.75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Abstract
SIGNIFICANCE Hydrogen peroxide (H2O2) is not only a key mediator of oxidative stress but also one of the most important cellular second messengers. This small short-lived molecule is involved in the regulation of a wide range of different biological processes, including regulation of cellular signaling pathways. Studying the role of H2O2 in living systems would be challenging without modern approaches. A genetically encoded fluorescent biosensor, HyPer, is one of the most effective tools for this purpose. RECENT ADVANCES HyPer has been used by many investigators of redox signaling in various models of different scales: from cytoplasmic subcompartments and single cells to tissues of whole organisms. In many studies, the results obtained using HyPer have enabled a better understanding of the roles of H2O2 in these biological processes. However, much remains to be learned. CRITICAL ISSUES In this review, we focus on the uses of HyPer. We provide a general description of HyPer and its improved versions. Separate chapters are devoted to the results obtained by various groups who have used this biosensor for their experiments in living cells and organisms. FUTURE DIRECTIONS HyPer is an effective tool for H2O2 imaging in living systems as indicated by the increasing numbers of publications each year since its development. However, this biosensor requires further improvements. In particular, much brighter and more pH-stable versions of HyPer are necessary for imaging in mammalian tissues. Antioxid. Redox Signal. 24, 731-751.
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Affiliation(s)
- Dmitry S Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia
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Pearson GL, Mellett N, Chu KY, Boslem E, Meikle PJ, Biden TJ. A comprehensive lipidomic screen of pancreatic β-cells using mass spectroscopy defines novel features of glucose-stimulated turnover of neutral lipids, sphingolipids and plasmalogens. Mol Metab 2016; 5:404-414. [PMID: 27257600 PMCID: PMC4877660 DOI: 10.1016/j.molmet.2016.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 01/05/2023] Open
Abstract
Objective Glucose promotes lipid remodelling in pancreatic β-cells, and this is thought to contribute to the regulation of insulin secretion, but the metabolic pathways and potential signalling intermediates have not been fully elaborated. Methods Using mass spectrometry (MS) we quantified changes in approximately 300 lipid metabolites in MIN6 β-cells and isolated mouse islets following 1 h stimulation with glucose. Flux through sphingolipid pathways was also assessed in 3H-sphinganine-labelled cells using TLC. Results Glucose specifically activates the conversion of triacylglycerol (TAG) to diacylglycerol (DAG). This leads indirectly to the formation of 18:1 monoacylglycerol (MAG), via degradation of saturated/monounsaturated DAG species, such as 16:0_18:1 DAG, which are the most abundant, immediate products of glucose-stimulated TAG hydrolysis. However, 16:0-containing, di-saturated DAG species are a better direct marker of TAG hydrolysis since, unlike the 18:1-containing DAGs, they are predominately formed via this route. Using multiple reaction monitoring, we confirmed that in islets under basal conditions, 18:1 MAG is the most abundant species. We further demonstrated a novel site of glucose to enhance the conversion of ceramide to sphingomyelin (SM) and galactosylceramide (GalCer). Flux and product:precursor analyses suggest regulation of the enzyme SM synthase, which would constitute a separate mechanism for localized generation of DAG in response to glucose. Phosphatidylcholine (PC) plasmalogen (P) species, specifically those containing 20:4, 22:5 and 22:6 side chains, were also diminished in the presence of glucose, whereas the more abundant phosphatidylethanolamine plasmalogens were unchanged. Conclusion Our results highlight 18:1 MAG, GalCer, PC(P) and DAG/SM as potential contributors to metabolic stimulus-secretion coupling. Using mass spectroscopy lipidomics we have defined new aspects of glucose simulated lipid turnover in pancreatic beta cells. Glucose directly stimulates triacylglycerol hydrolysis, of which di-saturated diacylglycerol species are excellent markers. C18:1 is the most abundant monacylglycerol, and the one most obviously increased by glucose. Phosphatidylcholine plasmalogens with poly-unsaturated side chains are preferentially decreased by glucose. Glucose specifically enhances the conversion of ceramide to both sphingomyelin and galactosylceramide.
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Key Words
- (O), ether lipid
- (P), plasmalogen
- ATGL, adipose tissue glycerolipase
- CE, cholesterol ester
- COH, free cholesterol
- Ceramide
- DAG, diacylglycerol
- Diacylglycerol
- FA, fatty acid
- GSIS, glucose-stimulated insulin secretion
- GalCer, galactosylceramide
- GluCer, glucosylceramide
- HSL, hormone sensitive lipase
- Insulin secretion
- KRHB, Krebs Ringer Hepes Buffer
- MAG, monacylglycerol
- MHC, monohexosylceramide
- MS, mass spectrometry
- Monacylglycerol
- PC, phosphatidylcholine
- PE, phosphatidylethanolamine
- PI, phosphatidylinositol
- PKD, protein kinase D
- PLA2, phospholipase A2
- Pancreatic β-cell
- Plasmalogen
- SM, sphingomyelin
- TAG, triacylglycerol
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Affiliation(s)
- Gemma L Pearson
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia
| | - Natalie Mellett
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Kwan Yi Chu
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia
| | - Ebru Boslem
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
| | - Trevor J Biden
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia.
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Deeney JT, Belkina AC, Shirihai OS, Corkey BE, Denis GV. BET Bromodomain Proteins Brd2, Brd3 and Brd4 Selectively Regulate Metabolic Pathways in the Pancreatic β-Cell. PLoS One 2016; 11:e0151329. [PMID: 27008626 PMCID: PMC4805167 DOI: 10.1371/journal.pone.0151329] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/26/2016] [Indexed: 11/18/2022] Open
Abstract
Displacement of Bromodomain and Extra-Terminal (BET) proteins from chromatin has promise for cancer and inflammatory disease treatments, but roles of BET proteins in metabolic disease remain unexplored. Small molecule BET inhibitors, such as JQ1, block BET protein binding to acetylated lysines, but lack selectivity within the BET family (Brd2, Brd3, Brd4, Brdt), making it difficult to disentangle contributions of each family member to transcriptional and cellular outcomes. Here, we demonstrate multiple improvements in pancreatic β-cells upon BET inhibition with JQ1 or BET-specific siRNAs. JQ1 (50–400 nM) increases insulin secretion from INS-1 cells in a concentration dependent manner. JQ1 increases insulin content in INS-1 cells, accounting for increased secretion, in both rat and human islets. Higher concentrations of JQ1 decrease intracellular triglyceride stores in INS-1 cells, a result of increased fatty acid oxidation. Specific inhibition of both Brd2 and Brd4 enhances insulin transcription, leading to increased insulin content. Inhibition of Brd2 alone increases fatty acid oxidation. Overlapping yet discrete roles for individual BET proteins in metabolic regulation suggest new isoform-selective BET inhibitors may be useful to treat insulin resistant/diabetic patients. Results imply that cancer and diseases of chronic inflammation or disordered metabolism are related through shared chromatin regulatory mechanisms.
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Affiliation(s)
- Jude T. Deeney
- Department of Medicine, Section of Endocrinology, Obesity Research Center, Evans Biomedical Research Center; Boston University School of Medicine, 650 Albany Street, X804, Boston, Massachusetts 02118, United States of America
| | - Anna C. Belkina
- Flow Cytometry Core Facility, Boston University School of Medicine, 650 Albany Street, X326, Boston, Massachusetts 02118, United States of America
| | - Orian S. Shirihai
- Department of Medicine, Section of Endocrinology, Obesity Research Center, Evans Biomedical Research Center; Boston University School of Medicine, 650 Albany Street, X804, Boston, Massachusetts 02118, United States of America
| | - Barbara E. Corkey
- Department of Medicine, Section of Endocrinology, Obesity Research Center, Evans Biomedical Research Center; Boston University School of Medicine, 650 Albany Street, X804, Boston, Massachusetts 02118, United States of America
| | - Gerald V. Denis
- Department of Pharmacology and Experimental Therapeutics, and Section of Hematology/ Oncology, Cancer Research Center; Boston University School of Medicine, 72 East Concord Street, K520, Boston, Massachusetts 02118, United States of America
- * E-mail:
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Inhibition of Monoacylglycerol Lipase Activity Decreases Glucose-Stimulated Insulin Secretion in INS-1 (832/13) Cells and Rat Islets. PLoS One 2016; 11:e0149008. [PMID: 26867016 PMCID: PMC4750965 DOI: 10.1371/journal.pone.0149008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/26/2016] [Indexed: 01/06/2023] Open
Abstract
Lipid signals derived from lipolysis and membrane phospholipids play an important role in glucose-stimulated insulin secretion (GSIS), though the exact secondary signals remain unclear. Previous reports have documented a stimulatory role of exogenously added mono-acyl-glycerol (MAG) on insulin secretion from cultured β-cells and islets. In this report we have determined effects of increasing intracellular MAG in the β-cell by inhibiting mono-acyl-glycerol lipase (MGL) activity, which catalyzes the final step in triacylglycerol breakdown, namely the hydrolysis of MAG to glycerol and free fatty acid (FA). To determine the role of MGL in GSIS, we used three different pharmacological agents (JZL184, MJN110 and URB602). All three inhibited GSIS and depolarization-induced insulin secretion in INS-1 (832/13). JZL184 significantly inhibited both GSIS and depolarization-induced insulin secretion in rat islets. JZL184 significantly decreased lipolysis and increased both mono- and diacyglycerol species in INS-1 cells. Analysis of the kinetics of GSIS showed that inhibition was greater during the sustained phase of secretion. A similar pattern was observed in the response of Ca2+ to glucose and depolarization but to a lesser degree suggesting that altered Ca2+ handling alone could not explain the reduction in insulin secretion. In addition, a significant reduction in long chain-CoA (LC-CoA) was observed in INS-1 cells at both basal and stimulatory glucose following inhibition of MGL. Our data implicate an important role for MGL in insulin secretion.
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Abstract
Type 2 diabetes is a complex disease. It results from a failure of the body to maintain energy homoeostasis. Multicellular organisms have evolved complex strategies to preserve a relatively stable internal nutrient environment, despite fluctuations in external nutrient availability. This complex strategy involves the co-ordinated responses of multiple organs to promote storage or mobilization of energy sources according to the availability of nutrients and cellular bioenergetics needs. The endocrine pancreas plays a central role in these processes by secreting insulin and glucagon. When this co-ordinated effort fails, hyperglycaemia and hyperlipidaemia develops, characterizing a state of metabolic imbalance and ultimately overt diabetes. Although diabetes is most likely a collection of diseases, scientists are starting to identify genetic components and environmental triggers. Genome-wide association studies revealed that by and large, gene variants associated with type 2 diabetes are implicated in pancreatic β-cell function, suggesting that the β-cell may be the weakest link in the chain of events that results in diabetes. Thus, it is critical to understand how environmental cues affect the β-cell. Phosphoinositides are important 'decoders' of environmental cues. As such, these lipids have been implicated in cellular responses to a wide range of growth factors, hormones, stress agents, nutrients and metabolites. Here we will review some of the well-established and potential new roles for phosphoinositides in β-cell function/dysfunction and discuss how our knowledge of phosphoinositide signalling could aid in the identification of potential strategies for treating or preventing type 2 diabetes.
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Affiliation(s)
- Lucia E Rameh
- Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, U.S.A.
| | - Jude T Deeney
- Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, U.S.A
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Erion KA, Berdan CA, Burritt NE, Corkey BE, Deeney JT. Chronic Exposure to Excess Nutrients Left-shifts the Concentration Dependence of Glucose-stimulated Insulin Secretion in Pancreatic β-Cells. J Biol Chem 2015; 290:16191-201. [PMID: 25934392 DOI: 10.1074/jbc.m114.620351] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 01/21/2023] Open
Abstract
Hyperinsulinemia (HI) is elevated plasma insulin at basal glucose. Impaired glucose tolerance is associated with HI, although the exact cause and effect relationship remains poorly defined. We tested the hypothesis that HI can result from an intrinsic response of the β-cell to chronic exposure to excess nutrients, involving a shift in the concentration dependence of glucose-stimulated insulin secretion. INS-1 (832/13) cells were cultured in either a physiological (4 mm) or high (11 mm) glucose concentration with or without concomitant exposure to oleate. Isolated rat islets were also cultured with or without oleate. A clear hypersensitivity to submaximal glucose concentrations was evident in INS-1 cells cultured in excess nutrients such that the 25% of maximal (S0.25) glucose-stimulated insulin secretion was significantly reduced in cells cultured in 11 mm glucose (S0.25 = 3.5 mm) and 4 mm glucose with oleate (S0.25 = 4.5 mm) compared with 4 mm glucose alone (S0.25 = 5.7 mm). The magnitude of the left shift was linearly correlated with intracellular lipid stores in INS-1 cells (r(2) = 0.97). We observed no significant differences in the dose responses for glucose stimulation of respiration, NAD(P)H autofluorescence, or Ca(2+) responses between left- and right-shifted β-cells. However, a left shift in the sensitivity of exocytosis to Ca(2+) was documented in permeabilized INS-1 cells cultured in 11 versus 4 mm glucose (S0.25 = 1.1 and 1.7 μm, respectively). Our results suggest that the sensitivity of exocytosis to triggering is modulated by a lipid component, the levels of which are influenced by the culture nutrient environment.
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Affiliation(s)
- Karel A Erion
- From the Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Charles A Berdan
- From the Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Nathan E Burritt
- From the Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Barbara E Corkey
- From the Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Jude T Deeney
- From the Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118
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Protective Role of Nuclear Factor E2-Related Factor 2 against Acute Oxidative Stress-Induced Pancreatic β -Cell Damage. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:639191. [PMID: 25949772 PMCID: PMC4407529 DOI: 10.1155/2015/639191] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 03/16/2015] [Accepted: 03/18/2015] [Indexed: 12/30/2022]
Abstract
Oxidative stress is implicated in the pathogenesis of pancreatic β-cell dysfunction that occurs in both type 1 and type 2 diabetes. Nuclear factor E2-related factor 2 (NRF2) is a master regulator in the cellular adaptive response to oxidative stress. The present study found that MIN6 β-cells with stable knockdown of Nrf2 (Nrf2-KD) and islets isolated from Nrf2-knockout mice expressed substantially reduced levels of antioxidant enzymes in response to a variety of stressors. In scramble MIN6 cells or wild-type islets, acute exposure to oxidative stressors, including hydrogen peroxide (H2O2) and S-nitroso-N-acetylpenicillamine, resulted in cell damage as determined by decrease in cell viability, reduced ATP content, morphology changes of islets, and/or alterations of apoptotic biomarkers in a concentration- and/or time-dependent manner. In contrast, silencing of Nrf2 sensitized MIN6 cells or islets to the damage. In addition, pretreatment of MIN6 β-cells with NRF2 activators, including CDDO-Im, dimethyl fumarate (DMF), and tert-butylhydroquinone (tBHQ), protected the cells from high levels of H2O2-induced cell damage. Given that reactive oxygen species (ROS) are involved in regulating glucose-stimulated insulin secretion (GSIS) and persistent activation of NRF2 blunts glucose-triggered ROS signaling and GSIS, the present study highlights the distinct roles that NRF2 may play in pancreatic β-cell dysfunction that occurs in different stages of diabetes.
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Qureshi FM, Dejene EA, Corbin KL, Nunemaker CS. Stress-induced dissociations between intracellular calcium signaling and insulin secretion in pancreatic islets. Cell Calcium 2015; 57:366-375. [PMID: 25861744 DOI: 10.1016/j.ceca.2015.03.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/09/2015] [Indexed: 12/22/2022]
Abstract
In healthy pancreatic islets, glucose-stimulated changes in intracellular calcium ([Ca(2+)]i) provide a reasonable reflection of the patterns and relative amounts of insulin secretion. We report that [Ca(2+)]i in islets under stress, however, dissociates with insulin release in different ways for different stressors. Islets were exposed for 48h to a variety of stressors: cytokines (low-grade inflammation), 28mM glucose (28G, glucotoxicity), free fatty acids (FFAs, lipotoxicity), thapsigargin (ER stress), or rotenone (mitochondrial stress). We then measured [Ca(2+)]i and insulin release in parallel studies. Islets exposed to all stressors except rotenone displayed significantly elevated [Ca(2+)]i in low glucose, however, increased insulin secretion was only observed for 28G due to increased nifedipine-sensitive calcium-channel flux. Following 3-11mM glucose stimulation, all stressors substantially reduced the peak glucose-stimulated [Ca(2+)]i response (first phase). Thapsigargin and cytokines also substantially impacted aspects of calcium influx and ER calcium handling. Stressors did not significantly impact insulin secretion in 11mM glucose for any stressor, although FFAs showed a borderline reduction, which contributed to a significant decrease in the stimulation index (11:3mM glucose) observed for FFAs and also for 28G. We also clamped [Ca(2+)]i using 30mM KCl+250μM diazoxide to test the amplifying pathway. Only rotenone-treated islets showed a robust increase in 3-11mM glucose-stimulated insulin secretion under clamped conditions, suggesting that low-level mitochondrial stress might activate the metabolic amplifying pathway. We conclude that different stressors dissociate [Ca(2+)]i from insulin secretion differently: ER stressors (thapsigargin, cytokines) primarily affect [Ca(2+)]i but not conventional insulin secretion and 'metabolic' stressors (FFAs, 28G, rotenone) impacted insulin secretion.
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Affiliation(s)
- Farhan M Qureshi
- Department of Medicine, University of Virginia, Charlottesville, VA.,Department of Chemistry, University of Virginia, Charlottesville, VA
| | - Eden A Dejene
- Department of Medicine, University of Virginia, Charlottesville, VA.,Department of Chemistry, University of Virginia, Charlottesville, VA
| | - Kathryn L Corbin
- Department of Medicine, University of Virginia, Charlottesville, VA
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Uruno A, Yagishita Y, Yamamoto M. The Keap1–Nrf2 system and diabetes mellitus. Arch Biochem Biophys 2015; 566:76-84. [DOI: 10.1016/j.abb.2014.12.012] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/07/2014] [Accepted: 12/09/2014] [Indexed: 12/30/2022]
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Simmons AL, Schlezinger JJ, Corkey BE. What Are We Putting in Our Food That Is Making Us Fat? Food Additives, Contaminants, and Other Putative Contributors to Obesity. Curr Obes Rep 2014; 3:273-85. [PMID: 25045594 PMCID: PMC4101898 DOI: 10.1007/s13679-014-0094-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The "chemical obesogen" hypothesis conjectures that synthetic, environmental contaminants are contributing to the global epidemic of obesity. In fact, intentional food additives (e.g., artificial sweeteners and colors, emulsifiers) and unintentional compounds (e.g., bisphenol A, pesticides) are largely unstudied in regard to their effects on overall metabolic homeostasis. With that said, many of these contaminants have been found to dysregulate endocrine function, insulin signaling, and/or adipocyte function. Although momentum for the chemical obesogen hypothesis is growing, supportive, evidence-based research is lacking. In order to identify noxious synthetic compounds in the environment out of the thousands of chemicals that are currently in use, tools and models from toxicology should be adopted (e.g., functional high throughput screening methods, zebrafish-based assays). Finally, mechanistic insight into obesogen-induced effects will be helpful in elucidating their role in the obesity epidemic as well as preventing and reversing their effects.
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Affiliation(s)
- Amber L Simmons
- Department of Medicine, Boston University Medical Center, 650 Albany St., Rm X810, Boston MA 02118, Tel.: 617-638-7088, Fax.: 617-638-7124,
| | - Jennifer J Schlezinger
- Department of Environmental Health, Boston University School of Public Health, 715 Albany St., Rm R405, Boston, MA 02118. Tel.: 617-638-6497 Fax.: 617-638-6463.
| | - Barbara E Corkey
- Department of Medicine, Boston University Medical Center, 650 Albany St., Rm X810, Boston MA 02118, Tel.: 617-638-7088, Fax.: 617-638-7124,
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The furan fatty acid metabolite CMPF is elevated in diabetes and induces β cell dysfunction. Cell Metab 2014; 19:653-66. [PMID: 24703697 DOI: 10.1016/j.cmet.2014.03.008] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/30/2013] [Accepted: 02/26/2014] [Indexed: 02/02/2023]
Abstract
Gestational diabetes (GDM) results from failure of the β cells to adapt to increased metabolic demands; however, the cause of GDM and the extremely high rate of progression to type 2 diabetes (T2D) remains unknown. Using metabolomics, we show that the furan fatty acid metabolite 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) is elevated in the plasma of humans with GDM, as well as impaired glucose-tolerant and T2D patients. In mice, diabetic levels of plasma CMPF induced glucose intolerance, impaired glucose-stimulated insulin secretion, and decreased glucose utilization. Mechanistically, we show that CMPF acts directly on the β cell, causing impaired mitochondrial function, decreasing glucose-induced ATP accumulation, and inducing oxidative stress, resulting in dysregulation of key transcription factors and ultimately reduced insulin biosynthesis. Importantly, specifically blocking its transport through OAT3 or antioxidant treatment could prevent CMPF-induced β cell dysfunction. Thus, CMPF provides a link between β cell dysfunction and GDM/T2D that could be targeted therapeutically.
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JEŽEK P, OLEJÁR T, SMOLKOVÁ K, JEŽEK J, DLASKOVÁ A, PLECITÁ-HLAVATÁ L, ZELENKA J, ŠPAČEK T, ENGSTOVÁ H, PAJUELO REGUERA D, JABŮREK M. Antioxidant and Regulatory Role of Mitochondrial Uncoupling Protein UCP2 in Pancreatic β-cells. Physiol Res 2014; 63:S73-91. [DOI: 10.33549/physiolres.932633] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Research on brown adipose tissue and its hallmark protein, mitochondrial uncoupling protein UCP1, has been conducted for half a century and has been traditionally studied in the Institute of Physiology (AS CR, Prague), likewise UCP2 residing in multiple tissues for the last two decades. Our group has significantly contributed to the elucidation of UCP uncoupling mechanism, fully dependent on free fatty acids (FFAs) within the inner mitochondrial membrane. Now we review UCP2 physiological roles emphasizing its roles in pancreatic β-cells, such as antioxidant role, possible tuning of redox homeostasis (consequently UCP2 participation in redox regulations), and fine regulation of glucose-stimulated insulin secretion (GSIS). For example, NADPH has been firmly established as being a modulator of GSIS and since UCP2 may influence redox homeostasis, it likely affects NADPH levels. We also point out the role of phospholipase iPLA2 isoform in providing FFAs for the UCP2 antioxidant function. Such initiation of mild uncoupling hypothetically precedes lipotoxicity in pancreatic β-cells until it reaches the pathological threshold, after which the antioxidant role of UCP2 can be no more cell-protective, for example due to oxidative stress-accumulated mutations in mtDNA. These mechanisms, together with impaired autocrine insulin function belong to important causes of Type 2 diabetes etiology.
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Affiliation(s)
- P. JEŽEK
- Department of Membrane Transport Biophysics, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Malin SK, Kirwan JP, Sia CL, González F. Glucose-stimulated oxidative stress in mononuclear cells is related to pancreatic β-cell dysfunction in polycystic ovary syndrome. J Clin Endocrinol Metab 2014; 99:322-9. [PMID: 24203060 PMCID: PMC3879676 DOI: 10.1210/jc.2013-3177] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
CONTEXT Oxidative stress induced by reactive oxygen species (ROS) is involved in the development of pancreatic β-cell dysfunction. OBJECTIVE We determined the relationship between mononuclear cell (MNC)-derived ROS generation and p47phox protein content in response to glucose ingestion and β-cell function in women with polycystic ovary syndrome (PCOS). DESIGN This was a cross-sectional study. SETTING This study was conducted at an academic medical center. PARTICIPANTS Twenty-nine normoglycemic women with PCOS (13 lean, 16 obese) and 25 ovulatory controls (16 lean, 9 obese) underwent a 3-h 75-g oral glucose tolerance test (OGTT). MAIN OUTCOME VARIABLES Pancreatic β-cell function was calculated as glucose-stimulated insulin secretion (insulin/glucose area under the curve0-30 min; GSIS)×Matsuda index-derived insulin sensitivity (ISOGTT). ROS generation was measured by chemiluminescence, and p47phox protein was quantified by Western blotting in MNC isolated from blood samples obtained at 0 and 2 hours of the OGTT. RESULTS Compared with controls, women with PCOS exhibited a higher percent change from baseline in ROS generation and p47phox protein in conjunction with greater GSIS and a tendency toward lower β-cell function. Lean women with PCOS exhibited a greater percent change from baseline in ROS generation and p47phox protein yet had similar GSIS responses compared with lean controls despite having lower ISOGTT. For the combined groups, β-cell function was inversely related to ROS generation and p47phox protein. GSIS was directly related to body mass index, central obesity, and circulating androgens. CONCLUSION In normoglycemic women, obesity plays a role in exaggerating GSIS. However, MNC-derived oxidative stress is independent of obesity and may contribute to the decline in β-cell function in women with PCOS.
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Affiliation(s)
- Steven K Malin
- Department of Pathobiology (S.K.M., J.P.K.), Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195; Department of Nutrition (S.K.M., J.P.K.), School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106; and Department of Obstetrics and Gynecology (C.L.S., F.G.), Indiana University School of Medicine, Indianapolis, Indiana 46202
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Karunakaran U, Park KG. A systematic review of oxidative stress and safety of antioxidants in diabetes: focus on islets and their defense. Diabetes Metab J 2013; 37:106-12. [PMID: 23641350 PMCID: PMC3638220 DOI: 10.4093/dmj.2013.37.2.106] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A growing body of evidence suggests that hyperglycemia-induced oxidative stress plays an important role in diabetic complications, especially β-cell dysfunction and failure. Under physiological conditions, reactive oxygen species serve as second messengers that facilitate signal transduction and gene expression in pancreatic β-cells. However, under pathological conditions, an imbalance in redox homeostasis leads to aberrant tissue damage and β-cell death due to a lack of antioxidant defense systems. Taking into account the vulnerability of islets to oxidative damage, induction of endogenous antioxidant enzymes or exogenous antioxidant administration has been proposed as a way to protect β-cells against diabetic insults. Here, we consider recent insights into how the redox response becomes deregulated under diabetic conditions, as well as the therapeutic benefits of antioxidants, which may provide clues for developing strategies aimed at the treatment or prevention of diabetes associated with β-cell failure.
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Affiliation(s)
- Udayakumar Karunakaran
- Departments of Internal Medicine, Biochemistry and Cell Biology, Research Institute of Aging and Metabolism and World Class University Program, Kyungpook National University School of Medicine, Daegu, Korea
| | - Keun-Gyu Park
- Departments of Internal Medicine, Biochemistry and Cell Biology, Research Institute of Aging and Metabolism and World Class University Program, Kyungpook National University School of Medicine, Daegu, Korea
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