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Rabbani N, Thornalley PJ. Hexokinase-linked glycolytic overload and unscheduled glycolysis in hyperglycemia-induced pathogenesis of insulin resistance, beta-cell glucotoxicity, and diabetic vascular complications. Front Endocrinol (Lausanne) 2024; 14:1268308. [PMID: 38292764 PMCID: PMC10824962 DOI: 10.3389/fendo.2023.1268308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 12/12/2023] [Indexed: 02/01/2024] Open
Abstract
Hyperglycemia is a risk factor for the development of insulin resistance, beta-cell glucotoxicity, and vascular complications of diabetes. We propose the hypothesis, hexokinase-linked glycolytic overload and unscheduled glycolysis, in explanation. Hexokinases (HKs) catalyze the first step of glucose metabolism. Increased flux of glucose metabolism through glycolysis gated by HKs, when occurring without concomitant increased activity of glycolytic enzymes-unscheduled glycolysis-produces increased levels of glycolytic intermediates with overspill into effector pathways of cell dysfunction and pathogenesis. HK1 is saturated with glucose in euglycemia and, where it is the major HK, provides for basal glycolytic flux without glycolytic overload. HK2 has similar saturation characteristics, except that, in persistent hyperglycemia, it is stabilized to proteolysis by high intracellular glucose concentration, increasing HK activity and initiating glycolytic overload and unscheduled glycolysis. This drives the development of vascular complications of diabetes. Similar HK2-linked unscheduled glycolysis in skeletal muscle and adipose tissue in impaired fasting glucose drives the development of peripheral insulin resistance. Glucokinase (GCK or HK4)-linked glycolytic overload and unscheduled glycolysis occurs in persistent hyperglycemia in hepatocytes and beta-cells, contributing to hepatic insulin resistance and beta-cell glucotoxicity, leading to the development of type 2 diabetes. Downstream effector pathways of HK-linked unscheduled glycolysis are mitochondrial dysfunction and increased reactive oxygen species (ROS) formation; activation of hexosamine, protein kinase c, and dicarbonyl stress pathways; and increased Mlx/Mondo A signaling. Mitochondrial dysfunction and increased ROS was proposed as the initiator of metabolic dysfunction in hyperglycemia, but it is rather one of the multiple downstream effector pathways. Correction of HK2 dysregulation is proposed as a novel therapeutic target. Pharmacotherapy addressing it corrected insulin resistance in overweight and obese subjects in clinical trial. Overall, the damaging effects of hyperglycemia are a consequence of HK-gated increased flux of glucose metabolism without increased glycolytic enzyme activities to accommodate it.
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Affiliation(s)
| | - Paul J. Thornalley
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
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2
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San Martín A, Arce-Molina R, Aburto C, Baeza-Lehnert F, Barros LF, Contreras-Baeza Y, Pinilla A, Ruminot I, Rauseo D, Sandoval PY. Visualizing physiological parameters in cells and tissues using genetically encoded indicators for metabolites. Free Radic Biol Med 2022; 182:34-58. [PMID: 35183660 DOI: 10.1016/j.freeradbiomed.2022.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023]
Abstract
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
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Affiliation(s)
- A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile.
| | - R Arce-Molina
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - C Aburto
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Y Contreras-Baeza
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - A Pinilla
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - D Rauseo
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile
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3
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Brito MDF, Torre C, Silva-Lima B. Scientific Advances in Diabetes: The Impact of the Innovative Medicines Initiative. Front Med (Lausanne) 2021; 8:688438. [PMID: 34295913 PMCID: PMC8290522 DOI: 10.3389/fmed.2021.688438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/02/2021] [Indexed: 12/16/2022] Open
Abstract
Diabetes Mellitus is one of the World Health Organization's priority diseases under research by the first and second programmes of Innovative Medicines Initiative, with the acronyms IMI1 and IMI2, respectively. Up to October of 2019, 13 projects were funded by IMI for Diabetes & Metabolic disorders, namely SUMMIT, IMIDIA, DIRECT, StemBANCC, EMIF, EBiSC, INNODIA, RHAPSODY, BEAT-DKD, LITMUS, Hypo-RESOLVE, IM2PACT, and CARDIATEAM. In general, a total of €447 249 438 was spent by IMI in the area of Diabetes. In order to prompt a better integration of achievements between the different projects, we perform a literature review and used three data sources, namely the official project's websites, the contact with the project's coordinators and co-coordinator, and the CORDIS database. From the 662 citations identified, 185 were included. The data collected were integrated into the objectives proposed for the four IMI2 program research axes: (1) target and biomarker identification, (2) innovative clinical trials paradigms, (3) innovative medicines, and (4) patient-tailored adherence programmes. The IMI funded projects identified new biomarkers, medical and research tools, determinants of inter-individual variability, relevant pathways, clinical trial designs, clinical endpoints, therapeutic targets and concepts, pharmacologic agents, large-scale production strategies, and patient-centered predictive models for diabetes and its complications. Taking into account the scientific data produced, we provided a joint vision with strategies for integrating personalized medicine into healthcare practice. The major limitations of this article were the large gap of data in the libraries on the official project websites and even the Cordis database was not complete and up to date.
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Affiliation(s)
| | - Carla Torre
- Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.,Laboratory of Systems Integration Pharmacology, Clinical & Regulatory Science-Research Institute for Medicines (iMED.ULisboa), Lisbon, Portugal
| | - Beatriz Silva-Lima
- Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.,Laboratory of Systems Integration Pharmacology, Clinical & Regulatory Science-Research Institute for Medicines (iMED.ULisboa), Lisbon, Portugal
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4
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Horvat A, Muhič M, Smolič T, Begić E, Zorec R, Kreft M, Vardjan N. Ca 2+ as the prime trigger of aerobic glycolysis in astrocytes. Cell Calcium 2021; 95:102368. [PMID: 33621899 DOI: 10.1016/j.ceca.2021.102368] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 12/17/2022]
Abstract
Astroglial aerobic glycolysis, a process during which d-glucose is converted to l-lactate, a brain fuel and signal, is regulated by the plasmalemmal receptors, including adrenergic receptors (ARs) and purinergic receptors (PRs), modulating intracellular Ca2+ and cAMP signals. However, the extent to which the two signals regulate astroglial aerobic glycolysis is poorly understood. By using agonists to stimulate intracellular α1-/β-AR-mediated Ca2+/cAMP signals, β-AR-mediated cAMP and P2R-mediated Ca2+ signals and genetically encoded fluorescence resonance energy transfer-based glucose and lactate nanosensors in combination with real-time microscopy, we show that intracellular Ca2+, but not cAMP, initiates a robust increase in the concentration of intracellular free d-glucose ([glc]i) and l-lactate ([lac]i), both depending on extracellular d-glucose, suggesting Ca2+-triggered glucose uptake and aerobic glycolysis in astrocytes. When the glycogen shunt, a process of glycogen remodelling, was inhibited, the α1-/β-AR-mediated increases in [glc]i and [lac]i were reduced by ∼65 % and ∼30 %, respectively, indicating that at least ∼30 % of the utilization of d-glucose is linked to glycogen remodelling and aerobic glycolysis. Additional activation of β-AR/cAMP signals aided to α1-/β-AR-triggered [lac]i increase, whereas the [glc]i increase was unaltered. Taken together, an increase in intracellular Ca2+ is the prime mechanism of augmented aerobic glycolysis in astrocytes, while cAMP has only a moderate role. The results provide novel information on the signals regulating brain metabolism and open new avenues to explore whether astroglial Ca2+ signals are dysregulated and contribute to neuropathologies with impaired brain metabolism.
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Affiliation(s)
- Anemari Horvat
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Marko Muhič
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tina Smolič
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Ena Begić
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Marko Kreft
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia; Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Nina Vardjan
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia.
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5
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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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Chowdhury HH. Differences in cytosolic glucose dynamics in astrocytes and adipocytes measured by FRET-based nanosensors. Biophys Chem 2020; 261:106377. [PMID: 32302866 DOI: 10.1016/j.bpc.2020.106377] [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: 02/08/2020] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 11/17/2022]
Abstract
The cellular response to fluctuations in blood glucose levels consists of integrative regulation of cell glucose uptake and glucose utilization in the cytosol, resulting in altered levels of glucose in the cytosol. Cytosolic glucose is difficult to be measured in the intact tissue, however recently methods have become available that allow measurements of glucose in single living cells with fluorescence resonance energy transfer (FRET) based protein sensors. By studying the dynamics of cytosolic glucose levels in different experimental settings, we can gain insights into the properties of plasma membrane permeability to glucose and glucose utilization in the cytosol, and how these processes are modulated by different environmental conditions, agents and enzymes. In this review, we compare the cytosolic regulation of glucose in adipocytes and astrocytes - two important regulators of energy balance and glucose homeostasis in whole body and brain, respectively, with particular emphasis on the data obtained with FRET based protein sensors as well as other biochemical and molecular approaches.
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Affiliation(s)
- Helena H Chowdhury
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, 1000 Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia.
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7
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Cardenas-Diaz FL, Leavens KF, Kishore S, Osorio-Quintero C, Chen YJ, Stanger BZ, Wang P, French D, Gadue P. A Dual Reporter EndoC-βH1 Human β-Cell Line for Efficient Quantification of Calcium Flux and Insulin Secretion. Endocrinology 2020; 161:bqaa005. [PMID: 31960055 PMCID: PMC7028009 DOI: 10.1210/endocr/bqaa005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 01/07/2020] [Accepted: 01/20/2020] [Indexed: 02/07/2023]
Abstract
Human in vitro model systems of diabetes are critical to both study disease pathophysiology and offer a platform for drug testing. We have generated a set of tools in the human β-cell line EndoC-βH1 that allows the efficient and inexpensive characterization of β-cell physiology and phenotypes driven by disruption of candidate genes. First, we generated a dual reporter line that expresses a preproinsulin-luciferase fusion protein along with GCaMP6s. This reporter line allows the quantification of insulin secretion by measuring luciferase activity and calcium flux, a critical signaling step required for insulin secretion, via fluorescence microscopy. Using these tools, we demonstrate that the generation of the reporter human β-cell line was highly efficient and validated that luciferase activity could accurately reflect insulin secretion. Second, we used a lentiviral vector carrying the CRISPR-Cas9 system to generate candidate gene disruptions in the reporter line. We also show that we can achieve gene disruption in ~90% of cells using a CRISPR-Cas9 lentiviral system. As a proof of principle, we disrupt the β-cell master regulator, PDX1, and show that mutant EndoC-βH1 cells display impaired calcium responses and fail to secrete insulin when stimulated with high glucose. Furthermore, we show that PDX1 mutant EndoC-βH1 cells exhibit decreased expression of the β-cell-specific genes MAFA and NKX6.1 and increased GCG expression. The system presented here provides a platform to quickly and easily test β-cell functionality in wildtype and cells lacking a gene of interest.
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Affiliation(s)
- Fabian L Cardenas-Diaz
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Karla F Leavens
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Siddharth Kishore
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Catherine Osorio-Quintero
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Yi-Ju Chen
- Department of Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ben Z Stanger
- Department of Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Gastroenterology Division, Department of Medicine, Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia
| | - Pei Wang
- Departments of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Deborah French
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Paul Gadue
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
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Bearham J, Garnett JP, Schroeder V, Biggart MGS, Baines DL. Effective glucose metabolism maintains low intracellular glucose in airway epithelial cells after exposure to hyperglycemia. Am J Physiol Cell Physiol 2019; 317:C983-C992. [PMID: 31433692 PMCID: PMC6879884 DOI: 10.1152/ajpcell.00193.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/26/2019] [Accepted: 08/13/2019] [Indexed: 02/07/2023]
Abstract
The airway epithelium maintains differential glucose concentrations between the airway surface liquid (ASL, ~0.4 mM) and the blood/interstitium (5-6 mM), which is important for defense against infection. Glucose primarily moves from the blood to the ASL via paracellular movement, down its concentration gradient, across the tight junctions. However, there is evidence that glucose can move transcellularly across epithelial cells. Using a Förster resonance energy transfer sensor for glucose, we investigated intracellular glucose concentrations in airway epithelial cells and the role of hexokinases in regulating intracellular glucose concentrations in normoglycemic and hyperglycemic conditions. Our findings indicated that in airway epithelial cells (H441 or primary human bronchial epithelial cells) exposed to 5 mM glucose (normoglycemia), intracellular glucose concentration is in the micromolar range. Inhibition of facilitative glucose transporters (GLUTs) with cytochalasin B reduced intracellular glucose concentration. When cells were exposed to 15 mM glucose (hyperglycemia), intracellular glucose concentration was reduced. Airway cells expressed hexokinases I, II, and III. Inhibition with 3-bromopyruvate decreased hexokinase activity by 25% and elevated intracellular glucose concentration, but levels remained in the micromolar range. Exposure to hyperglycemia increased glycolysis, glycogen, and sorbitol. Thus, glucose enters the airway cell via GLUTs and is then rapidly processed by hexokinase-dependent and hexokinase-independent metabolic pathways to maintain low intracellular glucose concentrations. We propose that this prevents transcellular transport and aids the removal of glucose from the ASL and that the main route of entry for glucose into the ASL is via the paracellular pathway.
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Affiliation(s)
- Jade Bearham
- Institute for Infection and Immunity, St. George's University of London, London, United Kingdom
| | - James P Garnett
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma and Company, Biberach an der Riss, Germany
| | - Victoria Schroeder
- Immunology and Respiratory Diseases Research, Boehringer Ingelheim Pharma and Company, Biberach an der Riss, Germany
| | - Matthew G S Biggart
- Institute for Infection and Immunity, St. George's University of London, London, United Kingdom
| | - Deborah L Baines
- Institute for Infection and Immunity, St. George's University of London, London, United Kingdom
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9
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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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10
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Lorincz R, Emfinger CH, Walcher A, Giolai M, Krautgasser C, Remedi MS, Nichols CG, Meyer D. In vivo monitoring of intracellular Ca 2+ dynamics in the pancreatic β-cells of zebrafish embryos. Islets 2018; 10:221-238. [PMID: 30521410 PMCID: PMC6300091 DOI: 10.1080/19382014.2018.1540234] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Assessing the response of pancreatic islet cells to glucose stimulation is important for understanding β-cell function. Zebrafish are a promising model for studies of metabolism in general, including stimulus-secretion coupling in the pancreas. We used transgenic zebrafish embryos expressing a genetically-encoded Ca2+ sensor in pancreatic β-cells to monitor a key step in glucose induced insulin secretion; the elevations of intracellular [Ca2+]i. In vivo and ex vivo analyses of [Ca2+]i demonstrate that β-cell responsiveness to glucose is well established in late embryogenesis and that embryonic β-cells also respond to free fatty acid and amino acid challenges. In vivo imaging of whole embryos further shows that indirect glucose administration, for example by yolk injection, results in a slow and asynchronous induction of β-cell [Ca2+]i responses, while intravenous glucose injections cause immediate and islet-wide synchronized [Ca2+]i fluctuations. Finally, we demonstrate that embryos with disrupted mutation of the CaV1.2 channel gene cacna1c are hyperglycemic and that this phenotype is associated with glucose-independent [Ca2+]i fluctuation in β-cells. The data reveal a novel central role of cacna1c in β-cell specific stimulus-secretion coupling in zebrafish and demonstrate that the novel approach we propose - to monitor the [Ca2+]i dynamics in embryonic β-cells in vivo - will help to expand the understanding of β-cell physiological functions in healthy and diseased states.
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Affiliation(s)
- Reka Lorincz
- Institute of Molecular Biology/CMBI, University of Innsbruck, Innsbruck, Austria
| | - Christopher H. Emfinger
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Andrea Walcher
- Institute of Molecular Biology/CMBI, University of Innsbruck, Innsbruck, Austria
| | - Michael Giolai
- Institute of Molecular Biology/CMBI, University of Innsbruck, Innsbruck, Austria
| | - Claudia Krautgasser
- Institute of Molecular Biology/CMBI, University of Innsbruck, Innsbruck, Austria
| | - Maria S. Remedi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Colin G. Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University School of Medicine, St. Louis, MO, USA
| | - Dirk Meyer
- Institute of Molecular Biology/CMBI, University of Innsbruck, Innsbruck, Austria
- CONTACT Dirk Meyer Institute of Molecular Biology/CMBI, University of Innsbruck, Technikerstrasse 25, Innsbruck 6020, Austria
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11
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Agrawalla BK, Lee HW, Phue WH, Raju A, Kim JJ, Kim HM, Kang NY, Chang YT. Two-Photon Dye Cocktail for Dual-Color 3D Imaging of Pancreatic Beta and Alpha Cells in Live Islets. J Am Chem Soc 2017; 139:3480-3487. [DOI: 10.1021/jacs.6b12122] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Bikram Keshari Agrawalla
- Department
of Chemistry and Medicinal Chemistry Program, National University of Singapore, 3 Science Drive 3, 117543 Singapore
| | - Hyo Won Lee
- Department
of Energy Systems Research, Ajou University, Suwon 443749, Korea
| | - Wut-Hmone Phue
- Department
of Chemistry and Medicinal Chemistry Program, National University of Singapore, 3 Science Drive 3, 117543 Singapore
| | - Anandhkumar Raju
- Laboratory
of Bioimaging Probe Development, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667 Singapore
| | - Jong-Jin Kim
- Department
of Chemistry and Medicinal Chemistry Program, National University of Singapore, 3 Science Drive 3, 117543 Singapore
| | - Hwan Myung Kim
- Department
of Energy Systems Research, Ajou University, Suwon 443749, Korea
| | - Nam-Young Kang
- Laboratory
of Bioimaging Probe Development, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667 Singapore
| | - Young-Tae Chang
- Department
of Chemistry and Medicinal Chemistry Program, National University of Singapore, 3 Science Drive 3, 117543 Singapore
- Laboratory
of Bioimaging Probe Development, Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667 Singapore
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Neelankal John A, Morahan G, Jiang FX. Incomplete Re-Expression of Neuroendocrine Progenitor/Stem Cell Markers is a Key Feature of β-Cell Dedifferentiation. J Neuroendocrinol 2017; 29. [PMID: 27891681 DOI: 10.1111/jne.12450] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 01/23/2023]
Abstract
There is increasing evidence to suggest that type 2 diabetes mellitus (T2D), a pandemic metabolic disease, may be caused by β-cell dedifferentiation (βCD). However, there is currently no universal definition of βCD, and the underlying mechanism is poorly understood. We hypothesise that a high-glucose in vitro environment mimics hyperglycaemia in vivo and that β cells grown in this milieu over a long period will undergo dedifferentiation. In the present study, we report that the pancreatic β cell line mouse insulinoma 6 (MIN6) grown under a high-glucose condition did not undergo massive cell death but exhibited a glucose-stimulated insulin-secreting profile similar to that of immature β cells. The expression of insulin and the glucose-sensing molecule glucose transporter 2 (Glut2) in late passage MIN6 cells was significantly lower than the early passage at both the RNA and protein levels. Mechanistically, these cells also expressed significantly less of the 'pancreatic and duodenal homebox1' (Pdx1) β-cell transcription factor. Finally, passaged MIN6 cells dedifferentiated to demonstrate some features of β-cell precursors, as well as neuroendocrine markers, in addition to expressing both glucagon and insulin. Thus, we concluded that high-glucose passaged MIN6 cells passaged MIN6 cells. provide a cellular model of β-cell dedifferentiation that can help researchers develop a better understanding of this process. These findings provide new insights that may enhance knowledge of the pathophysiology of T2D and facilitate the establishment of a novel strategy by which this disease can be treated.
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Affiliation(s)
- A Neelankal John
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Australia
- School of Medicine And Pharmacology, University of Western Australia, Carwley, Australia
| | - G Morahan
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Australia
- School of Medicine And Pharmacology, University of Western Australia, Carwley, Australia
| | - F-X Jiang
- Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Australia
- School of Medicine And Pharmacology, University of Western Australia, Carwley, Australia
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13
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Valdebenito R, Ruminot I, Garrido-Gerter P, Fernández-Moncada I, Forero-Quintero L, Alegría K, Becker HM, Deitmer JW, Barros LF. Targeting of astrocytic glucose metabolism by beta-hydroxybutyrate. J Cereb Blood Flow Metab 2016; 36:1813-1822. [PMID: 26661221 PMCID: PMC5076786 DOI: 10.1177/0271678x15613955] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 07/14/2015] [Indexed: 11/17/2022]
Abstract
The effectiveness of ketogenic diets and intermittent fasting against neurological disorders has brought interest to the effects of ketone bodies on brain cells. These compounds are known to modify the metabolism of neurons, but little is known about their effect on astrocytes, cells that control the supply of glucose to neurons and also modulate neuronal excitability through the glycolytic production of lactate. Here we have used genetically-encoded Förster Resonance Energy Transfer nanosensors for glucose, pyruvate and ATP to characterize astrocytic energy metabolism at cellular resolution. Our results show that the ketone body beta-hydroxybutyrate strongly inhibited astrocytic glucose consumption in mouse astrocytes in mixed cultures, in organotypic hippocampal slices and in acute hippocampal slices prepared from ketotic mice, while blunting the stimulation of glycolysis by physiological and pathophysiological stimuli. The inhibition of glycolysis was paralleled by an increased ability of astrocytic mitochondria to metabolize pyruvate. These results support the emerging notion that astrocytes contribute to the neuroprotective effect of ketone bodies.
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Affiliation(s)
| | - Iván Ruminot
- General Zoology/University of Kaiserslautern, Kaiserslautern, Germany
| | - Pamela Garrido-Gerter
- Centro de Estudios Científicos, Valdivia, Chile Universidad Austral de Chile, Valdivia, Chile
| | | | | | | | - Holger M Becker
- General Zoology/University of Kaiserslautern, Kaiserslautern, Germany
| | - Joachim W Deitmer
- General Zoology/University of Kaiserslautern, Kaiserslautern, Germany
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14
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Wang X, Ma Y, Zhao M, Zhou M, Xiao Y, Sun Z, Tong L. Determination of glucose in human stomach cancer cell extracts and single cells by capillary electrophoresis with a micro-biosensor. J Chromatogr A 2016; 1469:128-134. [DOI: 10.1016/j.chroma.2016.09.054] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 01/11/2023]
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15
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Ilegems E, van Krieken PP, Edlund PK, Dicker A, Alanentalo T, Eriksson M, Mandic S, Ahlgren U, Berggren PO. Light scattering as an intrinsic indicator for pancreatic islet cell mass and secretion. Sci Rep 2015; 5:10740. [PMID: 26030284 PMCID: PMC5377231 DOI: 10.1038/srep10740] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/27/2015] [Indexed: 12/23/2022] Open
Abstract
The pancreatic islet of Langerhans is composed of endocrine cells producing and releasing hormones from secretory granules in response to various stimuli for maintenance of blood glucose homeostasis. In order to adapt to a variation in functional demands, these islets are capable of modulating their hormone secretion by increasing the number of endocrine cells as well as the functional response of individual cells. A failure in adaptive mechanisms will lead to inadequate blood glucose regulation and thereby to the development of diabetes. It is therefore necessary to develop tools for the assessment of both pancreatic islet mass and function, with the aim of understanding cellular regulatory mechanisms and factors guiding islet plasticity. Although most of the existing techniques rely on the use of artificial indicators, we present an imaging methodology based on intrinsic optical properties originating from mature insulin secretory granules within endocrine cells that reveals both pancreatic islet mass and function. We demonstrate the advantage of using this imaging strategy by monitoring in vivo scattering signal from pancreatic islets engrafted into the anterior chamber of the mouse eye, and how this versatile and noninvasive methodology permits the characterization of islet morphology and plasticity as well as hormone secretory status.
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Affiliation(s)
- E Ilegems
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm SE-171 76, Sweden
| | - P P van Krieken
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm SE-171 76, Sweden
| | - P K Edlund
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm SE-171 76, Sweden
| | - A Dicker
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm SE-171 76, Sweden
| | - T Alanentalo
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm SE-171 76, Sweden
| | - M Eriksson
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - S Mandic
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm SE-171 76, Sweden
| | - U Ahlgren
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - P-O Berggren
- 1] The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm SE-171 76, Sweden [2] Diabetes Research Institute, Miller School of Medicine, University of Miami, FL 33136, Miami [3] Lee Kong Chian School of Medicine, Nanyang Technological University, Imperial College London, Novena Campus, Singapore
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16
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Gurgul-Convey E, Kaminski MT, Lenzen S. Physiological characterization of the human EndoC-βH1 β-cell line. Biochem Biophys Res Commun 2015; 464:13-9. [PMID: 26028562 DOI: 10.1016/j.bbrc.2015.05.072] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 05/20/2015] [Indexed: 12/11/2022]
Abstract
In the new human EndoC-βH1 β-cell line, a detailed analysis of the physiological characteristics was performed. This new human β-cell line expressed all target structures on the gene and protein level, which are crucial for physiological function and insulin secretion induced by glucose and other secretagogues. Glucose influx measurements revealed an excellent uptake capacity of EndoC-βH1 β-cells by the Glut1 and Glut2 glucose transporters. A high expression level of glucokinase enabled efficient glucose phosphorylation, increasing the ATP/ADP ratio along with stimulation of insulin secretion in the physiological glucose concentration range. The EC50 value of glucose for insulin secretion was 10.3 mM. Mannoheptulose, a specific glucokinase inhibitor, blocked glucose-induced insulin secretion (GSIS). The nutrient insulin secretagogues l-leucine and 2-ketoisocaproate also stimulated insulin secretion, with a potentiating effect of l-glutamine. The Kir 6.2 potassium channel blocker glibenclamide and Bay K 8644, an opener of the voltage-sensitive Ca(2+) channel significantly potentiated GSIS. Potentiation of GSIS by IBMX and forskolin went along with a strong stimulation of cAMP generation. In conclusion, the new human EndoC-βH1 β-cell line fully mirrors the analogous physiological characteristics of primary mouse, rat and human β-cells. Thus, this new human EndoC-βH1 β-cell line is very well suited for physiological β-cell studies.
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Affiliation(s)
- Ewa Gurgul-Convey
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Martin T Kaminski
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Sigurd Lenzen
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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San Martín A, Sotelo-Hitschfeld T, Lerchundi R, Fernández-Moncada I, Ceballo S, Valdebenito R, Baeza-Lehnert F, Alegría K, Contreras-Baeza Y, Garrido-Gerter P, Romero-Gómez I, Barros LF. Single-cell imaging tools for brain energy metabolism: a review. NEUROPHOTONICS 2014; 1:011004. [PMID: 26157964 PMCID: PMC4478754 DOI: 10.1117/1.nph.1.1.011004] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/09/2014] [Accepted: 04/10/2014] [Indexed: 05/03/2023]
Abstract
Neurophotonics comes to light at a time in which advances in microscopy and improved calcium reporters are paving the way toward high-resolution functional mapping of the brain. This review relates to a parallel revolution in metabolism. We argue that metabolism needs to be approached both in vitro and in vivo, and that it does not just exist as a low-level platform but is also a relevant player in information processing. In recent years, genetically encoded fluorescent nanosensors have been introduced to measure glucose, glutamate, ATP, NADH, lactate, and pyruvate in mammalian cells. Reporting relative metabolite levels, absolute concentrations, and metabolic fluxes, these sensors are instrumental for the discovery of new molecular mechanisms. Sensors continue to be developed, which together with a continued improvement in protein expression strategies and new imaging technologies, herald an exciting era of high-resolution characterization of metabolism in the brain and other organs.
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Affiliation(s)
- Alejandro San Martín
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Tamara Sotelo-Hitschfeld
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Rodrigo Lerchundi
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Ignacio Fernández-Moncada
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Sebastian Ceballo
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
| | - Rocío Valdebenito
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
| | | | - Karin Alegría
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
| | - Yasna Contreras-Baeza
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Pamela Garrido-Gerter
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Ignacio Romero-Gómez
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - L. Felipe Barros
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, 5110466, Chile
- Address all correspondence to: L. Felipe Barros, E-mail:
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18
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Kaminski MT, Schultz J, Waterstradt R, Tiedge M, Lenzen S, Baltrusch S. Glucose-induced dissociation of glucokinase from its regulatory protein in the nucleus of hepatocytes prior to nuclear export. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:554-64. [DOI: 10.1016/j.bbamcr.2013.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/18/2013] [Accepted: 12/04/2013] [Indexed: 12/12/2022]
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19
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Yin L, Vijaygopal P, MacGregor GG, Menon R, Ranganathan P, Prabhakaran S, Zhang L, Zhang M, Binder HJ, Okunieff P, Vidyasagar S. Glucose stimulates calcium-activated chloride secretion in small intestinal cells. Am J Physiol Cell Physiol 2014; 306:C687-96. [PMID: 24477233 DOI: 10.1152/ajpcell.00174.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The sodium-coupled glucose transporter-1 (SGLT1)-based oral rehydration solution (ORS) used in the management of acute diarrhea does not substantially reduce stool output, despite the fact that glucose stimulates the absorption of sodium and water. To explain this phenomenon, we investigated the possibility that glucose might also stimulate anion secretion. Transepithelial electrical measurements and isotope flux measurements in Ussing chambers were used to study the effect of glucose on active chloride and fluid secretion in mouse small intestinal cells and human Caco-2 cells. Confocal fluorescence laser microscopy and immunohistochemistry measured intracellular changes in calcium, sodium-glucose linked transporter, and calcium-activated chloride channel (anoctamin 1) expression. In addition to enhancing active sodium absorption, glucose increased intracellular calcium and stimulated electrogenic chloride secretion. Calcium imaging studies showed increased intracellular calcium when intestinal cells were exposed to glucose. Niflumic acid, but not glibenclamide, inhibited glucose-stimulated chloride secretion in mouse small intestines and in Caco-2 cells. Glucose-stimulated chloride secretion was not seen in ileal tissues incubated with the intracellular calcium chelater BAPTA-AM and the sodium-potassium-2 chloride cotransporter 1 (NKCC1) blocker bumetanide. These observations establish that glucose not only stimulates active Na absorption, a well-established phenomenon, but also induces a Ca-activated chloride secretion. This may explain the failure of glucose-based ORS to markedly reduce stool output in acute diarrhea. These results have immediate potential to improve the treatment outcomes for acute and/or chronic diarrheal diseases by replacing glucose with compounds that do not stimulate chloride secretion.
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Affiliation(s)
- Liangjie Yin
- Department of Radiation Oncology, University of Florida Shands Cancer Center, Cancer and Genetics Research Complex, Gainesville, Florida
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Naujok O, Bandou Y, Shikama Y, Funaki M, Lenzen S. Effect of substrate rigidity in tissue culture on the function of insulin-secreting INS-1E cells. J Tissue Eng Regen Med 2014; 11:58-65. [DOI: 10.1002/term.1857] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 09/05/2013] [Accepted: 11/10/2013] [Indexed: 11/10/2022]
Affiliation(s)
- O. Naujok
- Institute of Clinical Biochemistry; Hannover Medical School; Germany
| | - Y. Bandou
- Clinical Research Centre for Diabetes; Tokushima University Hospital; Japan
| | - Y. Shikama
- Clinical Research Centre for Diabetes; Tokushima University Hospital; Japan
| | - M. Funaki
- Clinical Research Centre for Diabetes; Tokushima University Hospital; Japan
| | - S. Lenzen
- Institute of Clinical Biochemistry; Hannover Medical School; Germany
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21
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Redox homeostasis in pancreatic β cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:932838. [PMID: 23304259 PMCID: PMC3532876 DOI: 10.1155/2012/932838] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 10/30/2012] [Indexed: 12/20/2022]
Abstract
We reviewed mechanisms that determine reactive oxygen species (redox) homeostasis, redox information signaling and metabolic/regulatory function of autocrine insulin signaling in pancreatic β cells, and consequences of oxidative stress and dysregulation of redox/information signaling for their dysfunction. We emphasize the role of mitochondrion in β cell molecular physiology and pathology, including the antioxidant role of mitochondrial uncoupling protein UCP2. Since in pancreatic β cells pyruvate cannot be easily diverted towards lactate dehydrogenase for lactate formation, the respiration and oxidative phosphorylation intensity are governed by the availability of glucose, leading to a certain ATP/ADP ratio, whereas in other cell types, cell demand dictates respiration/metabolism rates. Moreover, we examine the possibility that type 2 diabetes mellitus might be considered as an inevitable result of progressive self-accelerating oxidative stress and concomitantly dysregulated information signaling in peripheral tissues as well as in pancreatic β cells. It is because the redox signaling is inherent to the insulin receptor signaling mechanism and its impairment leads to the oxidative and nitrosative stress. Also emerging concepts, admiting participation of redox signaling even in glucose sensing and insulin release in pancreatic β cells, fit in this view. For example, NADPH has been firmly established to be a modulator of glucose-stimulated insulin release.
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