1
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Cuozzo F, Viloria K, Shilleh AH, Nasteska D, Frazer-Morris C, Tong J, Jiao Z, Boufersaoui A, Marzullo B, Rosoff DB, Smith HR, Bonner C, Kerr-Conte J, Pattou F, Nano R, Piemonti L, Johnson PRV, Spiers R, Roberts J, Lavery GG, Clark A, Ceresa CDL, Ray DW, Hodson L, Davies AP, Rutter GA, Oshima M, Scharfmann R, Merrins MJ, Akerman I, Tennant DA, Ludwig C, Hodson DJ. LDHB contributes to the regulation of lactate levels and basal insulin secretion in human pancreatic β cells. Cell Rep 2024; 43:114047. [PMID: 38607916 PMCID: PMC11164428 DOI: 10.1016/j.celrep.2024.114047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 02/19/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Using 13C6 glucose labeling coupled to gas chromatography-mass spectrometry and 2D 1H-13C heteronuclear single quantum coherence NMR spectroscopy, we have obtained a comparative high-resolution map of glucose fate underpinning β cell function. In both mouse and human islets, the contribution of glucose to the tricarboxylic acid (TCA) cycle is similar. Pyruvate fueling of the TCA cycle is primarily mediated by the activity of pyruvate dehydrogenase, with lower flux through pyruvate carboxylase. While the conversion of pyruvate to lactate by lactate dehydrogenase (LDH) can be detected in islets of both species, lactate accumulation is 6-fold higher in human islets. Human islets express LDH, with low-moderate LDHA expression and β cell-specific LDHB expression. LDHB inhibition amplifies LDHA-dependent lactate generation in mouse and human β cells and increases basal insulin release. Lastly, cis-instrument Mendelian randomization shows that low LDHB expression levels correlate with elevated fasting insulin in humans. Thus, LDHB limits lactate generation in β cells to maintain appropriate insulin release.
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Affiliation(s)
- Federica Cuozzo
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Katrina Viloria
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Ali H Shilleh
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Charlotte Frazer-Morris
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jason Tong
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Zicong Jiao
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Geneplus-Beijing, Changping District, Beijing 102206, China
| | - Adam Boufersaoui
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Bryan Marzullo
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Daniel B Rosoff
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; Oxford Kavli Centre for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Hannah R Smith
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Caroline Bonner
- University of Lille, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire de Lille (CHU Lille), Institute Pasteur Lille, U1190 -European Genomic Institute for Diabetes (EGID), F59000 Lille, France
| | - Julie Kerr-Conte
- University of Lille, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire de Lille (CHU Lille), Institute Pasteur Lille, U1190 -European Genomic Institute for Diabetes (EGID), F59000 Lille, France
| | - Francois Pattou
- University of Lille, Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire de Lille (CHU Lille), Institute Pasteur Lille, U1190 -European Genomic Institute for Diabetes (EGID), F59000 Lille, France
| | - Rita Nano
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
| | - Lorenzo Piemonti
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
| | - Paul R V Johnson
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Rebecca Spiers
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Jennie Roberts
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Centre for Systems Health and Integrated Metabolic Research (SHiMR), Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Carlo D L Ceresa
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - David W Ray
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; Oxford Kavli Centre for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Amy P Davies
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK; CHUM Research Centre and Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Masaya Oshima
- Université Paris Cité, Institut Cochin, INSERM U1016, CNRS UMR 8104, 75014 Paris, France
| | - Raphaël Scharfmann
- Université Paris Cité, Institut Cochin, INSERM U1016, CNRS UMR 8104, 75014 Paris, France
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Ildem Akerman
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
| | - Daniel A Tennant
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK.
| | - Christian Ludwig
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK.
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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2
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Vaishali, Adlakha N. Model of Calcium Dynamics Regulating [Formula: see text], ATP and Insulin Production in a Pancreatic [Formula: see text]-Cell. Acta Biotheor 2024; 72:2. [PMID: 38334878 DOI: 10.1007/s10441-024-09477-x] [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: 02/21/2023] [Accepted: 12/30/2023] [Indexed: 02/10/2024]
Abstract
The calcium signals regulate the production and secretion of many signaling molecules like inositol trisphosphate ([Formula: see text]) and adenosine triphosphate (ATP) in various cells including pancreatic [Formula: see text]-cells. The calcium signaling mechanisms regulating [Formula: see text], ATP and insulin responsible for various functions of [Formula: see text]-cells are still not well understood. Any disturbance in these mechanisms can alter the functions of [Formula: see text]-cells leading to diabetes and metabolic disorders. Therefore, a mathematical model is proposed by incorporating the reaction-diffusion equation for calcium dynamics and a system of first-order differential equations for [Formula: see text], ATP-production and insulin secretion with initial and boundary conditions. The model incorporates the temporal dependence of [Formula: see text]-production and degradation, ATP production and insulin secretion on calcium dynamics in a [Formula: see text]-cell. The piecewise linear finite element method has been used for the spatial dimension and the Crank-Nicolson scheme for the temporal dimension to obtain numerical results. The effect of changes in source influxes and buffers on calcium dynamics and production of [Formula: see text], ATP and insulin levels in a [Formula: see text]-cell has been analyzed. It is concluded that the dysfunction of source influx and buffers can cause significant variations in calcium levels and dysregulation of [Formula: see text], ATP and insulin production, which can lead to various metabolic disorders, diabetes, obesity, etc. The proposed model provides crucial information about the changes in mechanisms of calcium dynamics causing proportionate disturbances in [Formula: see text], ATP and insulin levels in pancreatic cells, which can be helpful for devising protocols for diagnosis and treatment of various metabolic diseases.
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Affiliation(s)
- Vaishali
- Department of Mathematics, SVNIT, Surat, Gujarat, 395007, India.
| | - Neeru Adlakha
- Department of Mathematics, SVNIT, Surat, Gujarat, 395007, India
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3
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Adlakha N. Disturbances in system dynamics of [Formula: see text] and [Formula: see text] perturbing insulin secretion in a pancreatic [Formula: see text]-cell due to type-2 diabetes. J Bioenerg Biomembr 2023:10.1007/s10863-023-09966-7. [PMID: 37418135 DOI: 10.1007/s10863-023-09966-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/27/2023] [Indexed: 07/08/2023]
Abstract
The individual study of [Formula: see text] and [Formula: see text] dynamics respectively in a [Formula: see text]-cell has yielded limited information about the cell functions. But the systems biology approaches for such studies have received very little attention by the research workers in the past. In the present work, a system-dynamics model for the interdependent [Formula: see text] and [Formula: see text] signaling that controls insulin secretion in a [Formula: see text]-cell has been suggested. A two-way feedback system of [Formula: see text] and [Formula: see text] has been considered and one-way feedback between [Formula: see text] and insulin has been implemented in the model. The finite element method along with the Crank-Nicolson method have been applied for simulation. Numerical results have been used to analyze the impact of perturbations in [Formula: see text] and [Formula: see text] dynamics on insulin secretion for normal and Type-2 diabetic conditions. The results reveal that Type-2 diabetes comes from abnormalities in insulin secretion caused by the perturbation in buffers and pumps (SERCA and PMCA).
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Affiliation(s)
- Neeru Adlakha
- Department of Mathematics and Humanities, SVNIT, Surat, 395007, Gujarat, India
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4
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Wu H, Zhang C, Zhu F, Zhu Y, Lu X, Wan Y, Su S, Chao J, Wang L, Zhu D. programmably engineered FRET-nanoflare for ratiometric live-cell ATP imaging with anti-interference capability. Chem Commun (Camb) 2023; 59:4047-4050. [PMID: 36928909 DOI: 10.1039/d3cc00690e] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Herein, we present a poly-adenine (polyA)-mediated programmably engineered FRET-nanoflare for ratiometric intracellular ATP imaging with anti-interference capability. The programmable polyA attachment is advantageous in enhancing the signal response for ATP. Moreover, the FRET-based nanoflare is capable of avoiding false-positive signals due to probe degradation in a complex environment, which has great potential for clinical diagnosis.
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Affiliation(s)
- Hongyu Wu
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Chengwen Zhang
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Fulin Zhu
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yu Zhu
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Xinhui Lu
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Ying Wan
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Shao Su
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Jie Chao
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Lianhui Wang
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Dan Zhu
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
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5
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Metabolic cycles and signals for insulin secretion. Cell Metab 2022; 34:947-968. [PMID: 35728586 PMCID: PMC9262871 DOI: 10.1016/j.cmet.2022.06.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 06/01/2022] [Accepted: 06/04/2022] [Indexed: 02/03/2023]
Abstract
In this review, we focus on recent developments in our understanding of nutrient-induced insulin secretion that challenge a key aspect of the "canonical" model, in which an oxidative phosphorylation-driven rise in ATP production closes KATP channels. We discuss the importance of intrinsic β cell metabolic oscillations; the phasic alignment of relevant metabolic cycles, shuttles, and shunts; and how their temporal and compartmental relationships align with the triggering phase or the secretory phase of pulsatile insulin secretion. Metabolic signaling components are assigned regulatory, effectory, and/or homeostatic roles vis-à-vis their contribution to glucose sensing, signal transmission, and resetting the system. Taken together, these functions provide a framework for understanding how allostery, anaplerosis, and oxidative metabolism are integrated into the oscillatory behavior of the secretory pathway. By incorporating these temporal as well as newly discovered spatial aspects of β cell metabolism, we propose a much-refined MitoCat-MitoOx model of the signaling process for the field to evaluate.
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6
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Komati A, Anand A, Nagendla NK, Madhusudana K, Mudiam MKR, Babu KS, Tiwari AK. Bombax ceiba
calyx displays antihyperglycemic activity via improving insulin secretion and sensitivity: Identification of bioactive phytometabolomes by UPLC‐QTof‐MS/MS. J Food Sci 2022; 87:1865-1881. [DOI: 10.1111/1750-3841.16093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 01/04/2022] [Accepted: 02/01/2022] [Indexed: 12/28/2022]
Affiliation(s)
- Anusha Komati
- Centre for Natural Products & Traditional Knowledge CSIR‐Indian Institute of Chemical Technology Hyderabad India
- Academy of Scientific & Innovative Research (AcSIR) Ghaziabad India
| | - Ajay Anand
- Centre for Natural Products & Traditional Knowledge CSIR‐Indian Institute of Chemical Technology Hyderabad India
- Academy of Scientific & Innovative Research (AcSIR) Ghaziabad India
- Carver College of Medicine, Department of Pathology, University Of Iowa Iowa City USA
| | - Narendra Kumar Nagendla
- Analytical & Structural Chemistry Department CSIR‐Indian Institute of Chemical Technology Hyderabad India
- Academy of Scientific & Innovative Research (AcSIR) Ghaziabad India
| | - Kuncha Madhusudana
- Applied Biology Division CSIR‐Indian Institute of Chemical Technology Hyderabad India
| | - Mohana Krishna Reddy Mudiam
- Analytical & Structural Chemistry Department CSIR‐Indian Institute of Chemical Technology Hyderabad India
- Academy of Scientific & Innovative Research (AcSIR) Ghaziabad India
| | - Katragadda Suresh Babu
- Centre for Natural Products & Traditional Knowledge CSIR‐Indian Institute of Chemical Technology Hyderabad India
- Academy of Scientific & Innovative Research (AcSIR) Ghaziabad India
| | - Ashok Kumar Tiwari
- Centre for Natural Products & Traditional Knowledge CSIR‐Indian Institute of Chemical Technology Hyderabad India
- Academy of Scientific & Innovative Research (AcSIR) Ghaziabad India
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7
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Zheng G, Zhao L, Yuan D, Li J, Yang G, Song D, Miao H, Shu L, Mo X, Xu X, Li L, Song X, Zhao Y. A genetically encoded fluorescent biosensor for monitoring ATP in living cells with heterobifunctional aptamers. Biosens Bioelectron 2022; 198:113827. [PMID: 34861524 DOI: 10.1016/j.bios.2021.113827] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 02/08/2023]
Abstract
Visualizing the dynamics of ATP in living cells is key to understanding cellular energy metabolism and related diseases. However, the live-cell applications of current methods are still limited due to challenges in biological compatibility and sensitivity to pH. Herein, a novel label-free fluorescent " turn-on " biosensor for monitoring ATP in living bacterias and mammalian cells was developed. This biosensor (Broc-ATP) employed heterobifunctional aptamers to detect ATP with high sensitivity in vitro. In our system, a very useful tandem method was established by combining four Broc-ATPs with 3 × F30 three-way junction scaffold to construct an intracellular biosensor that achieves sufficient fluorescence to respond to intracellular ATP. This intracellular biosensor can be used for sensitive and specific dynamic imaging of ATP in mammalian cells. Hence, this genetically encoded biosensor provides a robust and efficient tool for the detection of intracellular ATP dynamics and 3 × F30 tandem method expands the application of heterobifunctional aptamers in mammalian cells.
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Affiliation(s)
- Guoliang Zheng
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Liang Zhao
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Deyu Yuan
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Jia Li
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Gang Yang
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Danxia Song
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Hui Miao
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China
| | - Linjuan Shu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Xianming Mo
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, PR China
| | - Xiaoding Xu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, PR China
| | - Ling Li
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China.
| | - Xu Song
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China.
| | - Yongyun Zhao
- Center for Functional Genomics and Bioinformatics, College of Life Science, Sichuan University, Chengdu, Sichuan, 610064, PR China.
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8
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Wang Y, Liang S, Mei M, Zhao Q, She G, Shi W, Mu L. Sensitive and Stable Thermometer Based on the Long Fluorescence Lifetime of Au Nanoclusters for Mitochondria. Anal Chem 2021; 93:15072-15079. [PMID: 34617743 DOI: 10.1021/acs.analchem.1c03092] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Detecting the temperature of intracellular mitochondria with high sensitivity and stability is crucial to understanding the cellular metabolism and revealing the processes of mitochondria-related physiology. In this paper, employing the long fluorescence lifetime of modified Au nanoclusters (mAuNCs) by 4-(carboxybutyl) triphenylphosphonium bromide, we developed a fluorescence lifetime thermometer with high sensitivity and stability for the temperature of the intracellular mitochondria. A high relative temperature sensitivity of 2.8% and excellent photostability were achieved from the present thermometer. After incubation with L929 cells, the mAuNCs could be endocytosed into the cells and targeted the mitochondria, and the temperature changes at the L929 cells' mitochondria, which were stimulated by carbonyl cyanide 3-chlorophenylhydrazone and Ca2+, were successfully detected via the fluorescence lifetime images of the mAuNCs. Furthermore, utilizing the mAuNCs, we clarified the effect of Mg2+ on the temperature of the intracellular mitochondria. The strategy of employing a material with a long fluorescence lifetime and remarkable stability to fabricate the fluorescence lifetime thermometer for mitochondria can be used to design various thermometers for other organelles.
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Affiliation(s)
- Yuan Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sen Liang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mingliang Mei
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiaowen Zhao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangwei She
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Wensheng Shi
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lixuan Mu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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9
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Zhou Y, Zou L, Li G, Shi T, Yu S, Wang F, Liu X. A Cooperatively Activatable DNA Nanoprobe for Cancer Cell-Selective Imaging of ATP. Anal Chem 2021; 93:13960-13966. [PMID: 34605640 DOI: 10.1021/acs.analchem.1c03284] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
DNA-based nanoprobes have attracted extensive interest in the field of bioanalysis. Notably, engineered DNA nanoprobes that can respond to multiple pathological parameters are desirable to detect targets precisely. Here we design a split aptamer/DNAzyme (aptazyme)-based DNA probe for fluorescence detection of ATP and further develop a cooperatively activatable DNA nanoprobe for tumor-specific imaging of ATP in vivo. The DNA nanoprobes comprising split aptazyme-coated MnO2 nanovectors have high stability and are synergistically activated by multiple biomarkers, GSH and ATP. Upon stimuli by overexpressed GSH in tumor cells, this DNA nanoprobe can release the aptazyme and self-supply cofactor Mn2+ of the DNAzyme. Sequentially, intracellular ATP induces the proper folding of the split ATP aptamer and Mn2+-dependent DNAzyme, which activates the specific cleavage of substrate and generates the optical readout signal. This nanoprobe exhibits remarkable resistance to enzymatic degradation, satisfactory biosafety, identifies ATP specifically within cancer cells, and selectively lights up solid tumors. Our research provides a reliable method for ATP imaging in cancer cells and opens a new avenue for biochemical research and highly accurate disease diagnosis.
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Affiliation(s)
- Yizhuo Zhou
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Lina Zou
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China.,College of Chemistry, Green Catalysis Center, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Gaiping Li
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China.,College of Chemistry, Green Catalysis Center, Zhengzhou University, Zhengzhou 450001, P. R. China
| | - Tianhui Shi
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Shuyi Yu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Fuan Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Xiaoqing Liu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
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10
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Thompson B, Satin LS. Beta-Cell Ion Channels and Their Role in Regulating Insulin Secretion. Compr Physiol 2021; 11:1-21. [PMID: 34636409 PMCID: PMC8935893 DOI: 10.1002/cphy.c210004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Beta cells of the pancreatic islet express many different types of ion channels. These channels reside in the β-cell plasma membrane as well as subcellular organelles and their coordinated activity and sensitivity to metabolism regulate glucose-dependent insulin secretion. Here, we review the molecular nature, expression patterns, and functional roles of many β-cell channels, with an eye toward explaining the ionic basis of glucose-induced insulin secretion. Our primary focus is on KATP and voltage-gated Ca2+ channels as these primarily regulate insulin secretion; other channels in our view primarily help to sculpt the electrical patterns generated by activated β-cells or indirectly regulate metabolism. Lastly, we discuss why understanding the physiological roles played by ion channels is important for understanding the secretory defects that occur in type 2 diabetes. © 2021 American Physiological Society. Compr Physiol 11:1-21, 2021.
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11
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Hauser MJB. Synchronisation of glycolytic activity in yeast cells. Curr Genet 2021; 68:69-81. [PMID: 34633492 DOI: 10.1007/s00294-021-01214-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/26/2021] [Accepted: 09/27/2021] [Indexed: 11/28/2022]
Abstract
Glycolysis is the central metabolic pathway of almost every cell and organism. Under appropriate conditions, glycolytic oscillations may occur in individual cells as well as in entire cell populations or tissues. In many biological systems, glycolytic oscillations drive coherent oscillations of other metabolites, for instance in cardiomyocytes near anorexia, or in pancreas where they lead to a pulsatile release of insulin. Oscillations at the population or tissue level require the cells to synchronize their metabolism. We review the progress achieved in studying a model organism for glycolytic oscillations, namely yeast. Oscillations may occur on the level of individual cells as well as on the level of the cell population. In yeast, the cell-to-cell interaction is realized by diffusion-mediated intercellular communication via a messenger molecule. The present mini-review focuses on the synchronisation of glycolytic oscillations in yeast. Synchronisation is a quorum-sensing phenomenon because the collective oscillatory behaviour of a yeast cell population ceases when the cell density falls below a threshold. We review the question, under which conditions individual cells in a sparse population continue or cease to oscillate. Furthermore, we provide an overview of the pathway leading to the onset of synchronized oscillations. We also address the effects of spatial inhomogeneities (e.g., the formation of spatial clusters) on the collective dynamics, and also review the emergence of travelling waves of glycolytic activity. Finally, we briefly review the approaches used in numerical modelling of synchronized cell populations.
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Affiliation(s)
- Marcus J B Hauser
- Faculty of Natural Science, Otto-Von-Guericke-Universität Magdeburg, 39106, Magdeburg, Germany.
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12
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Ng XW, Chung YH, Piston DW. Intercellular Communication in the Islet of Langerhans in Health and Disease. Compr Physiol 2021; 11:2191-2225. [PMID: 34190340 DOI: 10.1002/cphy.c200026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete insulin, glucagon, and somatostatin from the β-, α-, and δ-cells, respectively. Each islet cell type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact islets. Regulation of secretion involves interconnected mechanisms among and between islet cell types. Islet cells lose their normal functional signatures and secretory behaviors upon dispersal as compared to intact islets and in vivo. In dispersed islet cells, the glucose response of insulin secretion is attenuated from that seen from whole islets, coordinated oscillations in membrane potential and intracellular Ca2+ activity, as well as the two-phase insulin secretion profile, are missing, and glucagon secretion displays higher basal secretion profile and a reverse glucose-dependent response from that of intact islets. These observations highlight the critical roles of intercellular communication within the pancreatic islet, and how these communication pathways are crucial for proper hormonal and nonhormonal secretion and glucose homeostasis. Further, misregulated secretions of islet secretory products that arise from defective intercellular islet communication are implicated in diabetes. Intercellular communication within the islet environment comprises multiple mechanisms, including electrical synapses from gap junctional coupling, paracrine interactions among neighboring cells, and direct cell-to-cell contacts in the form of juxtacrine signaling. In this article, we describe the various mechanisms that contribute to proper islet function for each islet cell type and how intercellular islet communications are coordinated among the same and different islet cell types. © 2021 American Physiological Society. Compr Physiol 11:2191-2225, 2021.
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Affiliation(s)
- Xue W Ng
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - Yong H Chung
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
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13
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Luo L, Wang M, Zhou Y, Xiang D, Wang Q, Huang J, Liu J, Yang X, Wang K. Ratiometric Fluorescent DNA Nanostructure for Mitochondrial ATP Imaging in Living Cells Based on Hybridization Chain Reaction. Anal Chem 2021; 93:6715-6722. [PMID: 33887142 DOI: 10.1021/acs.analchem.1c00176] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
For intracellular molecular detection, the appropriate probes should include the abilities to enter target cells noninvasively, target specific sites, and then respond to the analytes reliably. Herein, a ratiometric fluorescent DNA nanostructure (RFDN) was designed for mitochondrial adenosine triphosphate (ATP) imaging in living cells. The DNA nanostructure was constructed by continuous hybridization of two hairpin DNA strands (HS1-Cy3 and HS2-Cy5) under the initiation of the trigger. HS1-Cy3 and HS2-Cy5 contained split aptamer fragments of ATP and are labeled with a fluorescent donor (Cy3) and acceptor (Cy5), respectively. The RFDN integrated multiple split aptamer fragments and increased the local concentration of sensing probes. The binding of ATP to aptamer fragments on the RFDN shortened the distance between Cy3 and Cy5, resulting in obvious ratiometric signals (fluorescence resonance energy transfer). The RFDN showed good biocompatibility and can be internalized into cells in a caveolin-dependent endocytosis pathway. The co-localization imaging results indicated that the DNA nanostructure could target the mitochondria via Cy3 and Cy5. Moreover, the confocal imaging results showed that the intracellular ATP changes stimulated by drugs in living cells could be indicated by the RFDN. In this way, the RFDN is expected to be a simple, flexible, and general platform for chemo/biosensing in living cells.
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Affiliation(s)
- Lei Luo
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Min Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Yuan Zhou
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Dongliu Xiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Qing Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Jin Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Jianbo Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Xiaohai Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China
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14
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Laguerre A, Keutler K, Hauke S, Schultz C. Regulation of Calcium Oscillations in β-Cells by Co-activated Cannabinoid Receptors. Cell Chem Biol 2021; 28:88-96.e3. [PMID: 33147441 DOI: 10.1016/j.chembiol.2020.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/26/2020] [Accepted: 10/16/2020] [Indexed: 01/07/2023]
Abstract
Pharmacological treatment of pancreatic β cells targeting cannabinoid receptors 1 and 2 (CB1 and CB2) has been shown to result in significant effects on insulin release, possibly by modulating intracellular calcium levels ([Ca2+]i). It is unclear how the interplay of CB1 and CB2 affects insulin secretion. Here, we demonstrate by the use of highly specific receptor antagonists and the recently developed photo-releasable endocannabinoid 2-arachidonoylglycerol that both receptors have counteracting effects on cytosolic calcium oscillations. We further show that both receptors are juxtaposed in a way that increases [Ca2+]i oscillations in silent β cells but dampens them in active ones. This study highlights a functional role of CB1 and CB2 acting in concert as a compensator/attenuator switch for regulating β cell excitability.
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Affiliation(s)
- Aurélien Laguerre
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA.
| | - Kaya Keutler
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA
| | - Sebastian Hauke
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, 69117 Heidelberg, Germany
| | - Carsten Schultz
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA.
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15
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Chen S, Yu D, Zhong W, Liu J, Liu J, Liu B, Zheng J, Yang R. Visualization of O 2/ATP cross-talk in living cells with a smart fluorescent nanoprobe. Chem Commun (Camb) 2021; 57:7786-7789. [PMID: 34264259 DOI: 10.1039/d1cc02644e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we propose a dual-responsive fluorescent nanoprobe to visualize the cross-talk between O2 and adenosine triphosphate (ATP) in living cells. We hope it will be a helpful tool for the further understanding of cellular metabolism and further facilitating risk warning in the process of adaptation to consistent environmental pressures in premalignant lesions.
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Affiliation(s)
- Shiya Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Institute of Chemical Biology and Nanomedicine (ICBN), Hunan University, Changsha, 410082, China.
| | - Dingwen Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Institute of Chemical Biology and Nanomedicine (ICBN), Hunan University, Changsha, 410082, China.
| | - Wen Zhong
- Department of Geriatrics, Department of General Medicine, Xiangya Hospital, Central South University, Changsha, 410008, P. R. China.
| | - Jin Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Institute of Chemical Biology and Nanomedicine (ICBN), Hunan University, Changsha, 410082, China.
| | - Jun Liu
- Department of Geriatrics, Department of General Medicine, Xiangya Hospital, Central South University, Changsha, 410008, P. R. China.
| | - Bo Liu
- Department of Geriatrics, Department of General Medicine, Xiangya Hospital, Central South University, Changsha, 410008, P. R. China.
| | - Jing Zheng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Institute of Chemical Biology and Nanomedicine (ICBN), Hunan University, Changsha, 410082, China.
| | - Ronghua Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Institute of Chemical Biology and Nanomedicine (ICBN), Hunan University, Changsha, 410082, China.
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16
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CDK2 limits the highly energetic secretory program of mature β cells by restricting PEP cycle-dependent K ATP channel closure. Cell Rep 2021; 34:108690. [PMID: 33503433 PMCID: PMC7882066 DOI: 10.1016/j.celrep.2021.108690] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 11/24/2020] [Accepted: 01/04/2021] [Indexed: 12/23/2022] Open
Abstract
Hallmarks of mature β cells are restricted proliferation and a highly energetic secretory state. Paradoxically, cyclin-dependent kinase 2 (CDK2) is synthesized throughout adulthood, its cytosolic localization raising the likelihood of cell cycle-independent functions. In the absence of any changes in β cell mass, maturity, or proliferation, genetic deletion of Cdk2 in adult β cells enhanced insulin secretion from isolated islets and improved glucose tolerance in vivo. At the single β cell level, CDK2 restricts insulin secretion by increasing KATP conductance, raising the set point for membrane depolarization in response to activation of the phosphoenolpyruvate (PEP) cycle with mitochondrial fuels. In parallel with reduced β cell recruitment, CDK2 restricts oxidative glucose metabolism while promoting glucose-dependent amplification of insulin secretion. This study provides evidence of essential, non-canonical functions of CDK2 in the secretory pathways of quiescent β cells. Despite loss of proliferative capacity with age, mature β cells continually synthesize CDK2. Sdao et al. demonstrate that CDK2 depletion in adult β cells improves glucose tolerance in vivo. By augmenting PEP cycle-dependent KATP channel closure, CDK2 inactivation lowers the set point for membrane depolarization, augmenting oxidative metabolism and insulin secretion.
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17
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Lewandowski SL, Cardone RL, Foster HR, Ho T, Potapenko E, Poudel C, VanDeusen HR, Sdao SM, Alves TC, Zhao X, Capozzi ME, de Souza AH, Jahan I, Thomas CJ, Nunemaker CS, Davis DB, Campbell JE, Kibbey RG, Merrins MJ. Pyruvate Kinase Controls Signal Strength in the Insulin Secretory Pathway. Cell Metab 2020; 32:736-750.e5. [PMID: 33147484 PMCID: PMC7685238 DOI: 10.1016/j.cmet.2020.10.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/30/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022]
Abstract
Pancreatic β cells couple nutrient metabolism with appropriate insulin secretion. Here, we show that pyruvate kinase (PK), which converts ADP and phosphoenolpyruvate (PEP) into ATP and pyruvate, underlies β cell sensing of both glycolytic and mitochondrial fuels. Plasma membrane-localized PK is sufficient to close KATP channels and initiate calcium influx. Small-molecule PK activators increase the frequency of ATP/ADP and calcium oscillations and potently amplify insulin secretion. PK restricts respiration by cyclically depriving mitochondria of ADP, which accelerates PEP cycling until membrane depolarization restores ADP and oxidative phosphorylation. Our findings support a compartmentalized model of β cell metabolism in which PK locally generates the ATP/ADP required for insulin secretion. Oscillatory PK activity allows mitochondria to perform synthetic and oxidative functions without any net impact on glucose oxidation. These findings suggest a potential therapeutic route for diabetes based on PK activation that would not be predicted by the current consensus single-state model of β cell function.
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Affiliation(s)
- Sophie L Lewandowski
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Rebecca L Cardone
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Hannah R Foster
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Thuong Ho
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Evgeniy Potapenko
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Chetan Poudel
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Halena R VanDeusen
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sophia M Sdao
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tiago C Alves
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Xiaojian Zhao
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Arnaldo H de Souza
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ishrat Jahan
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Craig J Thomas
- National Center for Advancing Translational Sciences, Rockville, MD 20850, USA
| | - Craig S Nunemaker
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Dawn Belt Davis
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Richard G Kibbey
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA; Department of Cellular & Molecular Physiology, Yale University, New Haven, CT 06520, USA.
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA.
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18
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Hong S, Zhang X, Lake RJ, Pawel GT, Guo Z, Pei R, Lu Y. A photo-regulated aptamer sensor for spatiotemporally controlled monitoring of ATP in the mitochondria of living cells. Chem Sci 2019; 11:713-720. [PMID: 34123044 PMCID: PMC8145946 DOI: 10.1039/c9sc04773e] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Fluorescent aptamer sensors have shown enormous potential for intracellular imaging of small molecule metabolites. Since metabolites distribute differently at different subcellular locations and their concentrations and locations fluctuate with time, methods are needed for spatiotemporally controlled monitoring of these metabolites. Built upon previous success in temporal control of aptamer-based sensors, we herein report an aptamer sensor containing a photocleavable linker and using DQAsomes to target mitochondria for spatiotemporally controlled monitoring of ATP in the mitochondria of living cells. The photocleavable modification on the DNA ATP aptamer sensor can prevent sensor activation before reaching mitochondria and the sensor can then be activated upon light irradiation. The sensor has a detection limit of 3.7 μM and high selectivity against other nucleotides, allowing detection of ATP concentration fluctuations in mitochondria induced by Ca2+ or oligomycin. This work represents the first successful delivery of a DNA aptamer sensor to mitochondria, providing a new platform for targeted delivery to subcellular organelles for monitoring energy producing processes, as well as mitochondrial dysfunction-related diseases in different cells. A photo-regulated ATP sensor coupled with cationic DQAsomes is developed for spatiotemporally controlled imaging of ATP in the mitochondria of living cells.![]()
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Affiliation(s)
- Shanni Hong
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences Suzhou 215123 China .,Department of Chemistry, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Xiaoting Zhang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210093 China
| | - Ryan J Lake
- Department of Chemistry, University of Illinois at Urbana-Champaign Urbana IL 61801 USA .,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Gregory T Pawel
- Department of Chemistry, University of Illinois at Urbana-Champaign Urbana IL 61801 USA .,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Zijian Guo
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210093 China
| | - Renjun Pei
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences Suzhou 215123 China
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign Urbana IL 61801 USA .,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
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19
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ATP-sensitive K + channels and mitochondrial permeability transition pore mediate effects of hydrogen sulfide on cytosolic Ca 2+ homeostasis and insulin secretion in β-cells. Pflugers Arch 2019; 471:1551-1564. [PMID: 31713764 DOI: 10.1007/s00424-019-02325-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/29/2019] [Accepted: 10/21/2019] [Indexed: 12/19/2022]
Abstract
Hydrogen sulfide (H2S) is endogenously produced in pancreatic ß cells and its level is elevated in diabetes. Here, we report that H2S affects insulin secretion via two mechanisms that converge on cytosolic free Ca2+ ([Ca2+]i), a key mediator of insulin exocytosis. Cellular calcium imaging, using Fura-2 or Fluo-4, showed that exposure of INS-1E cells to H2S (30-100 μM) reduced both [Ca2+]i levels (by 21.7 ± 2.3%) and oscillation frequency (p < 0.01, n = 4). Consistent with a role of plasma membrane KATP channels (plasma-KATP), the effects of H2S on [Ca2+]i were blocked by gliclazide (a blocker of plasma-KATP channels), but were mimicked by diazoxide (an activator of plasma-KATP channels). Surprisingly, when Ca2+ entry via plasma membrane was inhibited using Ca2+-free external solutions, H2S increased [Ca2+]i by 39.7 ± 3.6% suggesting Ca2+ release from intracellular stores. H2S-induced [Ca2+]i increases were abolished by either FCCP (which depletes Ca2+ stored in mitochondria) or cyclosporine A (an inhibitor of mitochondrial permeability transition pore, mPTP) suggesting that H2S induces Ca2+ release from mitochondria. Measurement of mitochondrial membrane potential (MMP) suggested that H2S causes MMP depolarization, which was blocked by cyclosporine A. Finally, insulin measurements by ELISA indicated that H2S decreased insulin release from INS-1E cells, but after plasma membrane Ca2+ entry was blocked by nifedipine, H2S-induced mitochondrial Ca2+ release is able to increase insulin release. Together, our results indicate that H2S has dual effects on insulin release suggesting that, with different metabolic conditions, H2S may differentially modulate the insulin release from pancreatic ß cells and play a role in ß cell dysfunction.
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20
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Zhang CH, Wang H, Liu JW, Sheng YY, Chen J, Zhang P, Jiang JH. Amplified Split Aptamer Sensor Delivered Using Block Copolymer Nanoparticles for Small Molecule Imaging in Living Cells. ACS Sens 2018; 3:2526-2531. [PMID: 30468073 DOI: 10.1021/acssensors.8b00670] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We develop a novel amplified split aptamer sensor for highly sensitive detection and imaging of small molecules in living cells by using cationic block copolymer nanoparticles (BCNs) with entrapped fluorescent conjugated polymer as a delivery agent. The design of a split aptamer as the initiator of hybridization chain reaction (HCR) affords the possibility of enhancing the signal-to-background ratio and thus allows high-contrast imaging for small molecules with relatively weak interactions with their aptamers. The novel design of using fluorescent cationic BCNs as the nanocarrier enables efficient and self-tracking transfection of DNA probes. Results reveal that BCNs exhibit high fluorescence brightness allowing direct tracking of the delivery location. The developed amplified split aptamer sensor is shown to have high sensitivity and selectivity for in vitro quantitative detection of adenosine triphosphate (ATP) with a detection limit of 30 nM. Live cell studies show that the sensor provides a "signal on" approach for specific, high-contrast imaging of ATP. The DNA sensor based HCR system may provide a new generally applicable platform for detection and imaging of low-abundance biomarkers.
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Affiliation(s)
- Chong-Hua Zhang
- State Key Laboratory of Chemo-Biosensing & Chemometrics, College of Chemistry & Chemical Engineering, Hunan University, Changsha 410082, China
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan, Hunan 411201, China
| | - Hong Wang
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan, Hunan 411201, China
| | - Jin-Wen Liu
- State Key Laboratory of Chemo-Biosensing & Chemometrics, College of Chemistry & Chemical Engineering, Hunan University, Changsha 410082, China
| | - Ying-Ying Sheng
- State Key Laboratory of Chemo-Biosensing & Chemometrics, College of Chemistry & Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jian Chen
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan, Hunan 411201, China
| | - Peisheng Zhang
- State Key Laboratory of Chemo-Biosensing & Chemometrics, College of Chemistry & Chemical Engineering, Hunan University, Changsha 410082, China
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan, Hunan 411201, China
| | - Jian-Hui Jiang
- State Key Laboratory of Chemo-Biosensing & Chemometrics, College of Chemistry & Chemical Engineering, Hunan University, Changsha 410082, China
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21
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Depaoli MR, Hay JC, Graier WF, Malli R. The enigmatic ATP supply of the endoplasmic reticulum. Biol Rev Camb Philos Soc 2018; 94:610-628. [PMID: 30338910 PMCID: PMC6446729 DOI: 10.1111/brv.12469] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/20/2018] [Accepted: 08/30/2018] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is a functionally and morphologically complex cellular organelle largely responsible for a variety of crucial functions, including protein folding, maturation and degradation. Furthermore, the ER plays an essential role in lipid biosynthesis, dynamic Ca2+ storage, and detoxification. Malfunctions in ER‐related processes are responsible for the genesis and progression of many diseases, such as heart failure, cancer, neurodegeneration and metabolic disorders. To fulfill many of its vital functions, the ER relies on a sufficient energy supply in the form of adenosine‐5′‐triphosphate (ATP), the main cellular energy source. Despite landmark discoveries and clarification of the functional principles of ER‐resident proteins and key ER‐related processes, the mechanism underlying ER ATP transport remains somewhat enigmatic. Here we summarize ER‐related ATP‐consuming processes and outline our knowledge about the nature and function of the ER energy supply.
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Affiliation(s)
- Maria R Depaoli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Jesse C Hay
- Division of Biological Sciences and Center for Structural and Functional Neuroscience, The University of Montana, 32 Campus Drive, HS410, Missoula, MT 59812-4824, U.S.A
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria.,BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria.,BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
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22
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Brinkrolf C, Henke NA, Ochel L, Pucker B, Kruse O, Lutter P. Modeling and Simulating the Aerobic Carbon Metabolism of a Green Microalga Using Petri Nets and New Concepts of VANESA. J Integr Bioinform 2018; 15:/j/jib.2018.15.issue-3/jib-2018-0018/jib-2018-0018.xml. [PMID: 30218605 PMCID: PMC6340121 DOI: 10.1515/jib-2018-0018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 08/16/2018] [Indexed: 12/21/2022] Open
Abstract
In this work we present new concepts of VANESA, a tool for modeling and simulation in systems biology. We provide a convenient way to handle mathematical expressions and take physical units into account. Simulation and result management has been improved, and syntax and consistency checks, based on physical units, reduce modeling errors. As a proof of concept, essential components of the aerobic carbon metabolism of the green microalga Chlamydomonas reinhardtii are modeled and simulated. The modeling process is based on xHPN Petri net formalism and simulation is performed with OpenModelica, a powerful environment and compiler for Modelica. VANESA, as well as OpenModelica, is open source, free-of-charge for non-commercial use, and is available at: http://agbi.techfak.uni-bielefeld.de/vanesa.
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Affiliation(s)
- Christoph Brinkrolf
- Bielefeld University, Faculty of Technology, Bioinformatics Department, Bielefeld, Germany
| | - Nadja A Henke
- Bielefeld University, Faculty of Biology and CeBiTec, Genetics of Prokaryotes, Bielefeld, Germany
| | - Lennart Ochel
- Bielefeld University, Faculty of Technology, Bioinformatics Department, Bielefeld, Germany.,Linköping University, Department of Computer and Information Science, Linköping, Sweden
| | - Boas Pucker
- Bielefeld University, Faculty of Biology and CeBiTec, Genome Research, Bielefeld, Germany.,University of Cambridge, Department of PlantSciences, Evolution and Diversity, Cambridge, UK
| | - Olaf Kruse
- Bielefeld University, Faculty of Biology and CeBiTec, Algae Biotechnology and Bioenergy, Bielefeld, Germany
| | - Petra Lutter
- Bielefeld University, Faculty of Biology and CeBiTec, Proteome and Metabolome Research, Bielefeld, Germany
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23
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Feng R, Xu Y, Zhao H, Duan X, Sun S. A novel platform self-assembled from squaraine-embedded Zn(ii) complexes for selective monitoring of ATP and its level fluctuation in mitotic cells. Analyst 2018; 141:3219-23. [PMID: 27143565 DOI: 10.1039/c6an00646a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using multiple interactions, a simple self-assembly based on a Zn(ii) coordination compound and squaraine () demonstrated a selective turn-on fluorescence response to ATP in the near infrared (NIR) region. More importantly, the self-assembly has been successfully applied to ATP imaging in the mitochondria of the gastric cancer cell line SGC-7901 and monitoring of level fluctuation of ATP during the mitotic period.
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Affiliation(s)
- Ruizhi Feng
- College of Science, Northwest A&F University, Yangling 712100, Shaanxi, China.
| | - Yongqian Xu
- College of Science, Northwest A&F University, Yangling 712100, Shaanxi, China.
| | - Hongwei Zhao
- College of Science, Northwest A&F University, Yangling 712100, Shaanxi, China.
| | - Xuemei Duan
- College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Shiguo Sun
- College of Science, Northwest A&F University, Yangling 712100, Shaanxi, China.
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24
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Mellem D, Fischer F, Jaspers S, Wenck H, Rübhausen M. Mitochondrial Morphologies Driven by Energy-Consuming Cell Sites in a Spatially and Time-Resolved Quality Model. J Comput Biol 2018; 26:76-85. [PMID: 30204488 DOI: 10.1089/cmb.2018.0086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mitochondria are the energy plants of eukaryotic cells. Mitochondrial network morphologies are essential for the energy supply of eukaryotic cells. However, the associated dynamics are not yet fully understood. They behave as a dynamic network that adapts to the cell's environment and its energetic needs. Various processes such as mitochondrial fission and fusion, mitochondrial recycling, repair mechanisms, and oxidative stress influence the state of the mitochondrial network. Here, we introduce a novel time-dependent and spatially resolved quality model on mitochondrial morphology. The interplay between the mitochondrial network and energy-consuming cell sites is modeled by biophysical interactions of quality-dependent mitochondrial clusters in the presence of adenosine triphosphate (ATP) consumers represented by Mie potentials. Mitochondria are modeled as simplified ballistic particles that move within the cytoplasm of a virtual cell, and connect and divide by inelastic collisions. With this model, we investigate the coupling of mitochondrial dynamics with oscillating cell functions, representing diverse global states of the energetic architecture in the cell. Our simulations based on a generalized cell reveal a perinuclear condensation of mitochondria during phases of high-energy demand. Furthermore, quality-increasing mechanisms disclose the benefits of high mitochondrial masses. Simulations reveal that varying energy demands modeled by oscillations of ATP consumers alter the morphology of the network. Phases of high-energy consumption lead to interconnected network structures and perinuclear condensation of mitochondria. The model explains quality-increasing benefits of high mitochondrial masses.
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Affiliation(s)
- Daniel Mellem
- 1 Center for Free-Electron Laser Science (CFEL), University of Hamburg, Advanced Study Group, Hamburg, Germany.,2 Beiersdorf AG, Hamburg, Germany
| | | | | | | | - Michael Rübhausen
- 1 Center for Free-Electron Laser Science (CFEL), University of Hamburg, Advanced Study Group, Hamburg, Germany
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25
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Hashim M, Yokoi N, Takahashi H, Gheni G, Okechi OS, Hayami T, Murao N, Hidaka S, Minami K, Mizoguchi A, Seino S. Inhibition of SNAT5 Induces Incretin-Responsive State From Incretin-Unresponsive State in Pancreatic β-Cells: Study of β-Cell Spheroid Clusters as a Model. Diabetes 2018; 67:1795-1806. [PMID: 29954738 DOI: 10.2337/db17-1486] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 06/11/2018] [Indexed: 11/13/2022]
Abstract
β-Cell-β-cell interactions are required for normal regulation of insulin secretion. We previously found that formation of spheroid clusters (called K20-SC) from MIN6-K20 clonal β-cells lacking incretin-induced insulin secretion (IIIS) under monolayer culture (called K20-MC) drastically induced incretin responsiveness. Here we investigated the mechanism by which an incretin-unresponsive state transforms to an incretin-responsive state using K20-SC as a model. Glutamate production by glucose through the malate-aspartate shuttle and cAMP signaling, both of which are critical for IIIS, were enhanced in K20-SC. SC formed from β-cells deficient for aspartate aminotransferase 1, a critical enzyme in the malate-aspartate shuttle, exhibited reduced IIIS. Expression of the sodium-coupled neutral amino acid transporter 5 (SNAT5), which is involved in glutamine transport, was downregulated in K20-SC and pancreatic islets of normal mice but was upregulated in K20-MC and islets of rodent models of obesity and diabetes, both of which exhibit impaired IIIS. Inhibition of SNAT5 significantly increased cellular glutamate content and improved IIIS in islets of these models and in K20-MC. These results suggest that suppression of SNAT5 activity, which results in increased glutamate production, and enhancement of cAMP signaling endows incretin-unresponsive β-cells with incretin responsiveness.
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MESH Headings
- Amino Acid Transport Systems, Neutral/agonists
- Amino Acid Transport Systems, Neutral/antagonists & inhibitors
- Amino Acid Transport Systems, Neutral/genetics
- Amino Acid Transport Systems, Neutral/metabolism
- Animals
- Anti-Obesity Agents/pharmacology
- Cell Communication/drug effects
- Cell Line
- Cells, Cultured
- Clone Cells
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Drug Resistance/drug effects
- Gene Expression Regulation/drug effects
- Hypoglycemic Agents/pharmacology
- Incretins/pharmacology
- Insulin-Secreting Cells/drug effects
- Insulin-Secreting Cells/metabolism
- Insulin-Secreting Cells/pathology
- Insulin-Secreting Cells/ultrastructure
- Islets of Langerhans/drug effects
- Islets of Langerhans/metabolism
- Islets of Langerhans/pathology
- Islets of Langerhans/ultrastructure
- Male
- Membrane Transport Modulators/pharmacology
- Mice, Inbred Strains
- Microscopy, Electron, Transmission
- Models, Biological
- Obesity/drug therapy
- Obesity/metabolism
- Obesity/pathology
- RNA Interference
- Spheroids, Cellular/drug effects
- Spheroids, Cellular/metabolism
- Spheroids, Cellular/pathology
- Spheroids, Cellular/ultrastructure
- Tissue Culture Techniques
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Affiliation(s)
- Mahira Hashim
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
- Kansai Electric Power Medical Research Institute, Kobe, Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
- Kansai Electric Power Medical Research Institute, Kobe, Japan
| | - Ghupurjan Gheni
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Oduori S Okechi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohide Hayami
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
- Kansai Electric Power Medical Research Institute, Kobe, Japan
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University, Nagakute, Japan
| | - Naoya Murao
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shihomi Hidaka
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kohtaro Minami
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Akira Mizoguchi
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
- Kansai Electric Power Medical Research Institute, Kobe, Japan
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26
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Tozzi M, Larsen AT, Lange SC, Giannuzzo A, Andersen MN, Novak I. The P2X7 receptor and pannexin-1 are involved in glucose-induced autocrine regulation in β-cells. Sci Rep 2018; 8:8926. [PMID: 29895988 PMCID: PMC5997690 DOI: 10.1038/s41598-018-27281-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 05/31/2018] [Indexed: 01/02/2023] Open
Abstract
Extracellular ATP is an important short-range signaling molecule that promotes various physiological responses virtually in all cell types, including pancreatic β-cells. It is well documented that pancreatic β-cells release ATP through exocytosis of insulin granules upon glucose stimulation. We hypothesized that glucose might stimulate ATP release through other non-vesicular mechanisms. Several purinergic receptors are found in β-cells and there is increasing evidence that purinergic signaling regulates β-cell functions and survival. One of the receptors that may be relevant is the P2X7 receptor, but its detailed role in β-cell physiology is unclear. In this study we investigated roles of the P2X7 receptor and pannexin-1 in ATP release, intracellular ATP, Ca2+ signals, insulin release and cell proliferation/survival in β-cells. Results show that glucose induces rapid release of ATP and significant fraction of release involves the P2X7 receptor and pannexin-1, both expressed in INS-1E cells, rat and mouse β-cells. Furthermore, we provide pharmacological evidence that extracellular ATP, via P2X7 receptor, stimulates Ca2+ transients and cell proliferation in INS-1E cells and insulin secretion in INS-1E cells and rat islets. These data indicate that the P2X7 receptor and pannexin-1 have important functions in β-cell physiology, and should be considered in understanding and treatment of diabetes.
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Affiliation(s)
- Marco Tozzi
- Section for Cell Biology and Physiology, August Krogh Building, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Anna T Larsen
- Section for Cell Biology and Physiology, August Krogh Building, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Sofie C Lange
- Section for Cell Biology and Physiology, August Krogh Building, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Andrea Giannuzzo
- Section for Cell Biology and Physiology, August Krogh Building, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Martin N Andersen
- Section for Cell Biology and Physiology, August Krogh Building, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ivana Novak
- Section for Cell Biology and Physiology, August Krogh Building, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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27
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Fioramonti X, Chrétien C, Leloup C, Pénicaud L. Recent Advances in the Cellular and Molecular Mechanisms of Hypothalamic Neuronal Glucose Detection. Front Physiol 2017; 8:875. [PMID: 29184506 PMCID: PMC5694446 DOI: 10.3389/fphys.2017.00875] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/18/2017] [Indexed: 11/18/2022] Open
Abstract
The hypothalamus have been recognized for decades as one of the major brain centers for the control of energy homeostasis. This area contains specialized neurons able to detect changes in nutrients level. Among them, glucose-sensing neurons use glucose as a signaling molecule in addition to its fueling role. In this review we will describe the different sub-populations of glucose-sensing neurons present in the hypothalamus and highlight their nature in terms of neurotransmitter/neuropeptide expression. This review will particularly discuss whether pro-opiomelanocortin (POMC) neurons from the arcuate nucleus are directly glucose-sensing. In addition, recent observations in glucose-sensing suggest a subtle system with different mechanisms involved in the detection of changes in glucose level and their involvement in specific physiological functions. Several data point out the critical role of reactive oxygen species (ROS) and mitochondria dynamics in the detection of increased glucose. This review will also highlight that ATP-dependent potassium (KATP) channels are not the only channels mediating glucose-sensing and discuss the new role of transient receptor potential canonical channels (TRPC). We will discuss the recent advances in the determination of glucose-sensing machinery and propose potential line of research needed to further understand the regulation of brain glucose detection.
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Affiliation(s)
- Xavier Fioramonti
- NutriNeuro, Institut National de la Recherche Agronomique, Université de Bordeaux, Bordeaux, France.,Centre des Sciences du Goût et de l'Alimentation, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté, Dijon, France
| | - Chloé Chrétien
- Centre des Sciences du Goût et de l'Alimentation, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté, Dijon, France
| | - Corinne Leloup
- Centre des Sciences du Goût et de l'Alimentation, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté, Dijon, France
| | - Luc Pénicaud
- Centre des Sciences du Goût et de l'Alimentation, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté, Dijon, France.,Stromalab, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Université de Toulouse, Toulouse, France
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28
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Zheng X, Peng R, Jiang X, Wang Y, Xu S, Ke G, Fu T, Liu Q, Huan S, Zhang X. Fluorescence Resonance Energy Transfer-Based DNA Nanoprism with a Split Aptamer for Adenosine Triphosphate Sensing in Living Cells. Anal Chem 2017; 89:10941-10947. [PMID: 28931278 DOI: 10.1021/acs.analchem.7b02763] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have developed a DNA nanoprobe for adenosine triphosphate (ATP) sensing in living cells, based on the split aptamer and the DNA triangular prism (TP). In which nucleic acid aptamer was split into two fragments, the stem of the split aptamer was respectively labeled donor and acceptor fluorophores that underwent a fluorescence resonance energy transfer if two ATP molecules were bound as target molecule to the recognition module. Hence, ATP as a target induced the self-assembly of split aptamer fragments and thereby brought the dual fluorophores into close proximity for high fluorescence resonance energy transfer (FRET) efficiency. In the in vitro assay, an almost 5-fold increase in FA/FD signal was observed, the fluorescence emission ratio was found to be linear with the concentration of ATP in the range of 0.03-2 mM, and the nanoprobe was highly selective toward ATP. For the strong protecting capability to nucleic acids from enzymatic cleavage and the excellent biocompatibility of the TP, the DNA TP nanoprobe exhibited high cellular permeability, fast response, and successfully realized "FRET-off" to "FRET-on" sensing of ATP in living cells. Moreover, the intracellular imaging experiments indicated that the DNA TP nanoprobe could effectively detect ATP and distinguish among changes of ATP levels in living cells. More importantly, using of the split aptamer and the FRET-off to FRET-on sensing mechanism could efficiently avoid false-positive signals. This design provided a strategy to develop biosensors based on the DNA nanostructures for intracellular molecules analysis.
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Affiliation(s)
- Xiaofang Zheng
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Ruizi Peng
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Xi Jiang
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Yaya Wang
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Shuai Xu
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Guoliang Ke
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Ting Fu
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Qiaoling Liu
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Shuangyan Huan
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
| | - Xiaobing Zhang
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University , Changsha 410082, People's Republic of China
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29
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Montemurro C, Vadrevu S, Gurlo T, Butler AE, Vongbunyong KE, Petcherski A, Shirihai OS, Satin LS, Braas D, Butler PC, Tudzarova S. Cell cycle-related metabolism and mitochondrial dynamics in a replication-competent pancreatic beta-cell line. Cell Cycle 2017; 16:2086-2099. [PMID: 28820316 DOI: 10.1080/15384101.2017.1361069] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cell replication is a fundamental attribute of growth and repair in multicellular organisms. Pancreatic beta-cells in adults rarely enter cell cycle, hindering the capacity for regeneration in diabetes. Efforts to drive beta-cells into cell cycle have so far largely focused on regulatory molecules such as cyclins and cyclin-dependent kinases (CDKs). Investigations in cancer biology have uncovered that adaptive changes in metabolism, the mitochondrial network, and cellular Ca2+ are critical for permitting cells to progress through the cell cycle. Here, we investigated these parameters in the replication-competent beta-cell line INS 832/13. Cell cycle synchronization of this line permitted evaluation of cell metabolism, mitochondrial network, and cellular Ca2+ compartmentalization at key cell cycle stages. The mitochondrial network is interconnected and filamentous at G1/S but fragments during the S and G2/M phases, presumably to permit sorting to daughter cells. Pyruvate anaplerosis peaks at G1/S, consistent with generation of biomass for daughter cells, whereas mitochondrial Ca2+ and respiration increase during S and G2/M, consistent with increased energy requirements for DNA and lipid synthesis. This synchronization approach may be of value to investigators performing live cell imaging of Ca2+ or mitochondrial dynamics commonly undertaken in INS cell lines because without synchrony widely disparate data from cell to cell would be expected depending on position within cell cycle. Our findings also offer insight into why replicating beta-cells are relatively nonfunctional secreting insulin in response to glucose. They also provide guidance on metabolic requirements of beta-cells for the transition through the cell cycle that may complement the efforts currently restricted to manipulating cell cycle to drive beta-cells through cell cycle.
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Affiliation(s)
- Chiara Montemurro
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Suryakiran Vadrevu
- b Department of Pharmacology and Brehm Diabetes Research Center , University of Michigan , Ann Arbor , MI , USA
| | - Tatyana Gurlo
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Alexandra E Butler
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Kenny E Vongbunyong
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Anton Petcherski
- c Division of Endocrinology, Department of Medicine, David Geffen School of Medicine , University of California, Los Angeles , Los Angeles , CA , USA
| | - Orian S Shirihai
- c Division of Endocrinology, Department of Medicine, David Geffen School of Medicine , University of California, Los Angeles , Los Angeles , CA , USA
| | - Leslie S Satin
- b Department of Pharmacology and Brehm Diabetes Research Center , University of Michigan , Ann Arbor , MI , USA
| | - Daniel Braas
- d Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA ; UCLA Metabolomics Center , University of California, Los Angeles , Los Angeles , CA , USA
| | - Peter C Butler
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Slavica Tudzarova
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA.,e Jonsson Comprehensive Cancer Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
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30
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Je HJ, Kim MG, Kwon HJ. Bioluminescence Assays for Monitoring Chondrogenic Differentiation and Cartilage Regeneration. SENSORS 2017; 17:s17061306. [PMID: 28587284 PMCID: PMC5492100 DOI: 10.3390/s17061306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 05/24/2017] [Accepted: 06/02/2017] [Indexed: 02/06/2023]
Abstract
Since articular cartilage has a limited regeneration potential, for developing biological therapies for cartilage regeneration it is important to study the mechanisms underlying chondrogenesis of stem cells. Bioluminescence assays can visualize a wide range of biological phenomena such as gene expression, signaling, metabolism, development, cellular movements, and molecular interactions by using visible light and thus contribute substantially to elucidation of their biological functions. This article gives a concise review to introduce basic principles of bioluminescence assays and applications of the technology to visualize the processes of chondrogenesis and cartilage regeneration. Applications of bioluminescence assays have been highlighted in the methods of real-time monitoring of gene expression and intracellular levels of biomolecules and noninvasive cell tracking within animal models. This review suggests that bioluminescence assays can be applied towards a visual understanding of chondrogenesis and cartilage regeneration.
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Affiliation(s)
- Hyeon Jeong Je
- Department of Physical Therapy and Rehabilitation Science, College of Health Science, Eulji University, Gyeonggi 13135, Korea.
| | - Min Gu Kim
- Department of Physical Therapy and Rehabilitation Science, College of Health Science, Eulji University, Gyeonggi 13135, Korea.
| | - Hyuck Joon Kwon
- Department of Physical Therapy and Rehabilitation Science, College of Health Science, Eulji University, Gyeonggi 13135, Korea.
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31
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Abstract
The pancreatic β-cell secretes insulin in response to elevated plasma glucose. This review applies an external bioenergetic critique to the central processes of glucose-stimulated insulin secretion, including glycolytic and mitochondrial metabolism, the cytosolic adenine nucleotide pool, and its interaction with plasma membrane ion channels. The control mechanisms responsible for the unique responsiveness of the cell to glucose availability are discussed from bioenergetic and metabolic control standpoints. The concept of coupling factor facilitation of secretion is critiqued, and an attempt is made to unravel the bioenergetic basis of the oscillatory mechanisms controlling secretion. The need to consider the physiological constraints operating in the intact cell is emphasized throughout. The aim is to provide a coherent pathway through an extensive, complex, and sometimes bewildering literature, particularly for those unfamiliar with the field.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Research on Aging, Novato, California; and Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmo, Sweden
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32
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Merrins MJ, Poudel C, McKenna JP, Ha J, Sherman A, Bertram R, Satin LS. Phase Analysis of Metabolic Oscillations and Membrane Potential in Pancreatic Islet β-Cells. Biophys J 2017; 110:691-699. [PMID: 26840733 DOI: 10.1016/j.bpj.2015.12.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 01/01/2023] Open
Abstract
Metabolism in islet β-cells displays oscillations that can trigger pulses of electrical activity and insulin secretion. There has been a decades-long debate among islet biologists about whether metabolic oscillations are intrinsic or occur in response to oscillations in intracellular Ca(2+) that result from bursting electrical activity. In this article, the dynamics of oscillatory metabolism were investigated using five different optical reporters. Reporter activity was measured simultaneously with membrane potential bursting to determine the phase relationships between the metabolic oscillations and electrical activity. Our experimental findings suggest that Ca(2+) entry into β-cells stimulates the rate of mitochondrial metabolism, accounting for the depletion of glycolytic intermediates during each oscillatory burst. We also performed Ca(2+) clamp tests in which we clamped membrane potential with the KATP channel-opener diazoxide and KCl to fix Ca(2+) at an elevated level. These tests confirm that metabolic oscillations do not require Ca(2+) oscillations, but show that Ca(2+) plays a larger role in shaping metabolic oscillations than previously suspected. A dynamical picture of the mechanisms of oscillations emerged that requires the restructuring of contemporary mathematical β-cell models, including our own dual oscillator model. In the companion article, we modified our model to account for these new data.
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Affiliation(s)
- Matthew J Merrins
- Division of Endocrinology, Diabetes & Metabolism, Department of Medicine and Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin; William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Chetan Poudel
- Division of Endocrinology, Diabetes & Metabolism, Department of Medicine and Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin; William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Joseph P McKenna
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida
| | - Joon Ha
- Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Arthur Sherman
- Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida
| | - Leslie S Satin
- Department of Pharmacology and Brehm Diabetes Center, University of Michigan, Ann Arbor, Michigan.
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Yang Y, Huang J, Yang X, Quan K, Wang H, Ying L, Xie N, Ou M, Wang K. Aptazyme-Gold Nanoparticle Sensor for Amplified Molecular Probing in Living Cells. Anal Chem 2016; 88:5981-7. [PMID: 27167489 DOI: 10.1021/acs.analchem.6b00999] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To date, a few of DNAzyme-based sensors have been successfully developed in living cells; however, the intracellular aptazyme sensor has remained underdeveloped. Here, the first aptazyme sensor for amplified molecular probing in living cells is developed. A gold nanoparticle (AuNP) is modified with substrate strands hybridized to aptazyme strands. Only the target molecule can activate the aptazyme and then cleave and release the fluorophore-labeled substrate strands from the AuNP, resulting in fluorescence enhancement. The process is repeated so that each copy of target can cleave multiplex fluorophore-labeled substrate strands, amplifying the fluorescence signal. Results show that the detection limit is about 200 nM, which is 2 or 3 orders of magnitude lower than that of the reported aptamer-based adenosine triphosphate (ATP) sensors used in living cells. Furthermore, it is demonstrated that the aptazyme sensor can readily enter living cells and realize intracellular target detection.
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Affiliation(s)
- Yanjing Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - Jin Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - Xiaohai Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - Ke Quan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - He Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - Le Ying
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - Nuli Xie
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - Min Ou
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
| | - Kemin Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University , Changsha 410082, People's Republic of China
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Marmugi A, Parnis J, Chen X, Carmichael L, Hardy J, Mannan N, Marchetti P, Piemonti L, Bosco D, Johnson P, Shapiro JAM, Cruciani-Guglielmacci C, Magnan C, Ibberson M, Thorens B, Valdivia HH, Rutter GA, Leclerc I. Sorcin Links Pancreatic β-Cell Lipotoxicity to ER Ca2+ Stores. Diabetes 2016; 65:1009-21. [PMID: 26822088 PMCID: PMC4806657 DOI: 10.2337/db15-1334] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/18/2016] [Indexed: 01/02/2023]
Abstract
Preserving β-cell function during the development of obesity and insulin resistance would limit the worldwide epidemic of type 2 diabetes. Endoplasmic reticulum (ER) calcium (Ca(2+)) depletion induced by saturated free fatty acids and cytokines causes β-cell ER stress and apoptosis, but the molecular mechanisms behind these phenomena are still poorly understood. Here, we demonstrate that palmitate-induced sorcin downregulation and subsequent increases in glucose-6-phosphatase catalytic subunit-2 (G6PC2) levels contribute to lipotoxicity. Sorcin is a calcium sensor protein involved in maintaining ER Ca(2+) by inhibiting ryanodine receptor activity and playing a role in terminating Ca(2+)-induced Ca(2+) release. G6PC2, a genome-wide association study gene associated with fasting blood glucose, is a negative regulator of glucose-stimulated insulin secretion (GSIS). High-fat feeding in mice and chronic exposure of human islets to palmitate decreases endogenous sorcin expression while levels of G6PC2 mRNA increase. Sorcin-null mice are glucose intolerant, with markedly impaired GSIS and increased expression of G6pc2 Under high-fat diet, mice overexpressing sorcin in the β-cell display improved glucose tolerance, fasting blood glucose, and GSIS, whereas G6PC2 levels are decreased and cytosolic and ER Ca(2+) are increased in transgenic islets. Sorcin may thus provide a target for intervention in type 2 diabetes.
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Affiliation(s)
- Alice Marmugi
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Julia Parnis
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Xi Chen
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI
| | - LeAnne Carmichael
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Julie Hardy
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Naila Mannan
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - Lorenzo Piemonti
- Diabetes Research Institute (HSR-DRI), San Raffaele Scientific Institute, Milan, Italy
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Paul Johnson
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, U.K
| | - James A M Shapiro
- Clinical Islet Laboratory and Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
| | | | - Christophe Magnan
- Unit of Functional and Adaptive Biology, Paris Diderot University-Paris 7, Paris, France
| | - Mark Ibberson
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Héctor H Valdivia
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K.
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K.
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Qiang W, Hu H, Sun L, Li H, Xu D. Aptamer/Polydopamine Nanospheres Nanocomplex for in Situ Molecular Sensing in Living Cells. Anal Chem 2015; 87:12190-6. [PMID: 26556471 DOI: 10.1021/acs.analchem.5b03075] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A nanocomplex was developed for molecular sensing in living cells, based on the fluorophore-labeled aptamer and the polydopamine nanospheres (PDANS). Due to the interaction between ssDNA and PDANS, the aptamer was adsorbed onto the surface of PDANS forming the aptamer/PDANS nanocomplex, and the fluorescence was quenched by PDANS through Förster resonance energy transfer (FRET). In vitro assay, the introduction of adenosine triphosphate (ATP) led to the dissociation of the aptamer from the PDANS and the recovery of the fluorescence. The retained fluorescence of the nanocomplex was found to be linear with the concentration of ATP in the range of 0.01-2 mM, and the nanocomplex was highly selective toward ATP. For the strong protecting capability to nucleic acids from enzymatic cleavage and the excellent biocompatibility of PDANS, the nanocomplex was transported into cells and successfully realized "signal on" sensing of ATP in living cells; moreover, the nanocomplex could be employed for ATP semiquantification. This design provides a strategy to develop biosensors based on the polydopamine nanomaterials for intracellular molecules analysis. For the advantages of polydopamine, it would be an excellent candidate for many biological applications, such as gene and drug delivery, intracellular imaging, and in vivo monitoring.
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Affiliation(s)
- Weibing Qiang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , 22 Hankou Road, Nanjing, Jiangsu 210093, China
| | - Hongting Hu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , 22 Hankou Road, Nanjing, Jiangsu 210093, China
| | - Liang Sun
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , 22 Hankou Road, Nanjing, Jiangsu 210093, China
| | - Hui Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , 22 Hankou Road, Nanjing, Jiangsu 210093, China
| | - Danke Xu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , 22 Hankou Road, Nanjing, Jiangsu 210093, China
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Spatiotemporal quantification of subcellular ATP levels in a single HeLa cell during changes in morphology. Sci Rep 2015; 5:16874. [PMID: 26575097 PMCID: PMC4647183 DOI: 10.1038/srep16874] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 10/21/2015] [Indexed: 11/09/2022] Open
Abstract
The quantitative relationship between change in cell shape and ATP consumption is an unsolved problem in cell biology. In this study, a simultaneous imaging and image processing analysis allowed us to observe and quantify these relationships under physiological conditions, for the first time. We focused on two marginal regions of cells: the microtubule-rich 'lamella' and the actin-rich 'peripheral structure'. Simultaneous imaging and correlation analysis revealed that microtubule dynamics cause lamellar shape change accompanying an increase in ATP level. Also, image processing and spatiotemporal quantification enabled to visualize a chronological change of the relationships between the protrusion length and ATP levels, and it suggested they are influencing each other. Furthermore, inhibition of microtubule dynamics diminished motility in the peripheral structure and the range of fluctuation of ATP level in the lamella. This work clearly demonstrates that cellular motility and morphology are regulated by ATP-related cooperative function between microtubule and actin dynamics.
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Dual Monitoring of Secretion and ATP Levels during Chondrogenesis Using Perfusion Culture-Combined Bioluminescence Monitoring System. BIOMED RESEARCH INTERNATIONAL 2015; 2015:219068. [PMID: 26605325 PMCID: PMC4641928 DOI: 10.1155/2015/219068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 10/04/2015] [Accepted: 10/18/2015] [Indexed: 12/19/2022]
Abstract
Skeletal pattern formation in limb development depends on prechondrogenic condensation which prefigures the cartilage template. However, although morphogens such as TGF-βs and BMPs have been known to play essential roles in skeletal patterning, how the morphogens induce prechondrogenic cells to aggregate and determine patterns of cartilage elements has remained unclear. Our previous study reported that ATP oscillations are induced during chondrogenesis. This result suggests the possibility that ATP oscillations lead to the oscillatory secretion of morphogens, due to the fact that secretion process requires ATP. To examine the correlation between ATP oscillations and secretion levels of morphogens, we have developed perfusion culture-combined bioluminescence monitoring system to simultaneously monitor intracellular ATP levels and secretion levels. Using this system, we found that secretory activity oscillates in phase with ATP oscillations and that secretion levels of TGF-β1 and BMP2 oscillate during chondrogenesis. The oscillatory secretion of the morphogens would contribute to amplifying the fluctuation of the morphogens, underlie the spatial patterning of morphogens, and consequently lead to skeletal pattern formation.
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Gerencser AA. Bioenergetic Analysis of Single Pancreatic β-Cells Indicates an Impaired Metabolic Signature in Type 2 Diabetic Subjects. Endocrinology 2015. [PMID: 26204464 DOI: 10.1210/en.2015-1552] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Impaired activation of mitochondrial energy metabolism by glucose has been demonstrated in type 2 diabetic β-cells. The cause of this dysfunction is unknown. The aim of this study was to identify segments of energy metabolism with normal or with altered function in human type 2 diabetes mellitus. The mitochondrial membrane potential (ΔψM), and its response to glucose, is the main driver of mitochondrial ATP synthesis and is hence a central mediator of glucose-induced insulin secretion, but its quantitative determination in β-cells from human donors has not been attempted, due to limitations in assay technology. Here, novel fluorescence microscopic assays are exploited to quantify ΔψM and its response to glucose and other secretagogues in β-cells of dispersed pancreatic islet cells from 4 normal and 3 type 2 diabetic organ donors. Mitochondrial volume densities and the magnitude of ΔψM in low glucose were not consistently altered in diabetic β-cells. However, ΔψM was consistently less responsive to elevation of glucose concentration, whereas the decreased response was not observed with metabolizable secretagogue mixtures that feed directly into the tricarboxylic acid cycle. Single-cell analysis of the heterogeneous responses to metabolizable secretagogues indicated no dysfunction in relaying ΔψM hyperpolarization to plasma membrane potential depolarization in diabetic β-cells. ΔψM of diabetic β-cells was distinctly responsive to acute inhibition of ATP synthesis during glucose stimulation. It is concluded that the mechanistic deficit in glucose-induced insulin secretion and mitochondrial hyperpolarization of diabetic human β-cells is located upstream of the tricarboxylic acid cycle and manifests in dampening the control of ΔψM by glucose metabolism.
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Affiliation(s)
- Akos A Gerencser
- Buck Institute for Research on Aging and Image Analyst Software, Novato, California 94945; and College of Pharmacy, Touro University California, Vallejo, California 94592
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Patergnani S, Baldassari F, De Marchi E, Karkucinska-Wieckowska A, Wieckowski MR, Pinton P. Methods to monitor and compare mitochondrial and glycolytic ATP production. Methods Enzymol 2015; 542:313-32. [PMID: 24862273 DOI: 10.1016/b978-0-12-416618-9.00016-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
ATP is commonly considered as the main energy unit of the cell and participates in a variety of cellular processes. Thus, intracellular ATP concentrations rapidly vary in response to a wide variety of stimuli, including nutrients, hormones, cytotoxic agents, and hypoxia. Such alterations not necessarily affect cytosolic and mitochondrial ATP to similar extents. From an oncological perspective, this is particularly relevant in the course of tumor progression as well as in the response of cancer cells to therapy. In normal cells, mitochondrial oxidative phosphorylation (OXPHOS) is the predominant source of ATP. Conversely, many cancer cells exhibit an increased flux through glycolysis irrespective of oxygen tension. Assessing the relative contribution of glycolysis and OXPHOS to intracellular ATP production is fundamental not only for obtaining further insights into the peculiarities and complexities of oncometabolism but also for developing therapeutic and diagnostic tools. Several techniques have been developed to measure intracellular ATP levels including enzymatic methods based on hexokinase, glucose-6-phosphate dehydrogenase, and firefly luciferase. Here, we summarize conventional methods for measuring intracellular ATP levels and we provide a detailed protocol based on cytosol- and mitochondrion-targeted variants of firefly luciferase to determine the relative contribution of glycolysis and OXPHOS to ATP synthesis.
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Affiliation(s)
- Simone Patergnani
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Ferrara, Italy
| | - Federica Baldassari
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Ferrara, Italy
| | - Elena De Marchi
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Ferrara, Italy
| | | | - Mariusz R Wieckowski
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Paolo Pinton
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Ferrara, Italy.
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40
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Pancreatic β-cell identity, glucose sensing and the control of insulin secretion. Biochem J 2015; 466:203-18. [PMID: 25697093 DOI: 10.1042/bj20141384] [Citation(s) in RCA: 251] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Insulin release from pancreatic β-cells is required to maintain normal glucose homoeostasis in man and many other animals. Defective insulin secretion underlies all forms of diabetes mellitus, a disease currently reaching epidemic proportions worldwide. Although the destruction of β-cells is responsible for Type 1 diabetes (T1D), both lowered β-cell mass and loss of secretory function are implicated in Type 2 diabetes (T2D). Emerging results suggest that a functional deficiency, involving de-differentiation of the mature β-cell towards a more progenitor-like state, may be an important driver for impaired secretion in T2D. Conversely, at least in rodents, reprogramming of islet non-β to β-cells appears to occur spontaneously in models of T1D, and may occur in man. In the present paper, we summarize the biochemical properties which define the 'identity' of the mature β-cell as a glucose sensor par excellence. In particular, we discuss the importance of suppressing a group of 11 'disallowed' housekeeping genes, including Ldha and the monocarboxylate transporter Mct1 (Slc16a1), for normal nutrient sensing. We then survey the changes in the expression and/or activity of β-cell-enriched transcription factors, including FOXO1, PDX1, NKX6.1, MAFA and RFX6, as well as non-coding RNAs, which may contribute to β-cell de-differentiation and functional impairment in T2D. The relevance of these observations for the development of new approaches to treat T1D and T2D is considered.
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Watts M, Fendler B, Merrins MJ, Satin LS, Bertram R, Sherman A. Calcium and Metabolic Oscillations in Pancreatic Islets: Who's Driving the Bus? *. SIAM JOURNAL ON APPLIED DYNAMICAL SYSTEMS 2015; 13:683-703. [PMID: 25698909 PMCID: PMC4331037 DOI: 10.1137/130920198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Pancreatic islets exhibit bursting oscillations in response to elevated blood glucose. These oscillations are accompanied by oscillations in the free cytosolic Ca2+ concentration (Cac ), which drives pulses of insulin secretion. Both islet Ca2+ and metabolism oscillate, but there is some debate about their interrelationship. Recent experimental data show that metabolic oscillations in some cases persist after the addition of diazoxide (Dz), which opens K(ATP) channels, hyperpolarizing β-cells and preventing Ca2+ entry and Ca2+ oscillations. Further, in some islets in which metabolic oscillations were eliminated with Dz, increasing the cytosolic Ca2+ concentration by the addition of KCl could restart the metabolic oscillations. Here we address why metabolic oscillations persist in some islets but not others, and why raising Cac restarts oscillations in some islets but not others. We answer these questions using the dual oscillator model (DOM) for pancreatic islets. The DOM can reproduce the experimental data and shows that the model supports two different mechanisms for slow metabolic oscillations, one that requires calcium oscillations and one that does not.
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Affiliation(s)
- Margaret Watts
- National Institutes of Health, Bethesda, MD 20892. The first and sixth authors’ research was supported by the NIH/NIDDK Intramural Research Program
| | - Bernard Fendler
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724. This author’s research was supported by the Simons Foundation and the Starr Cancer Consortium (I3-A123)
| | - Matthew J. Merrins
- University of Michigan, Ann Arbor, MI 48105. The third author’s research was supported by the National Institutes of Health (F32-DK085960), and the fourth author’s research was supported by the National Institutes of Health (R01-DK46409)
| | - Leslie S. Satin
- University of Michigan, Ann Arbor, MI 48105. The third author’s research was supported by the National Institutes of Health (F32-DK085960), and the fourth author’s research was supported by the National Institutes of Health (R01-DK46409)
| | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, FL 32306. This author’s research was supported by the National Institutes of Health (DK080714)
| | - Arthur Sherman
- National Institutes of Health, Bethesda, MD 20892. The first and sixth authors’ research was supported by the NIH/NIDDK Intramural Research Program
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Wuttke A. Lipid Signalling Dynamics at the β-cell Plasma Membrane. Basic Clin Pharmacol Toxicol 2015; 116:281-90. [DOI: 10.1111/bcpt.12369] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/15/2014] [Indexed: 12/26/2022]
Affiliation(s)
- Anne Wuttke
- Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
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43
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Gilon P, Chae HY, Rutter GA, Ravier MA. Calcium signaling in pancreatic β-cells in health and in Type 2 diabetes. Cell Calcium 2014; 56:340-61. [DOI: 10.1016/j.ceca.2014.09.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/26/2014] [Accepted: 09/01/2014] [Indexed: 12/24/2022]
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De la Fuente IM, Cortés JM, Valero E, Desroches M, Rodrigues S, Malaina I, Martínez L. On the dynamics of the adenylate energy system: homeorhesis vs homeostasis. PLoS One 2014; 9:e108676. [PMID: 25303477 PMCID: PMC4193753 DOI: 10.1371/journal.pone.0108676] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 09/03/2014] [Indexed: 11/20/2022] Open
Abstract
Biochemical energy is the fundamental element that maintains both the adequate turnover of the biomolecular structures and the functional metabolic viability of unicellular organisms. The levels of ATP, ADP and AMP reflect roughly the energetic status of the cell, and a precise ratio relating them was proposed by Atkinson as the adenylate energy charge (AEC). Under growth-phase conditions, cells maintain the AEC within narrow physiological values, despite extremely large fluctuations in the adenine nucleotides concentration. Intensive experimental studies have shown that these AEC values are preserved in a wide variety of organisms, both eukaryotes and prokaryotes. Here, to understand some of the functional elements involved in the cellular energy status, we present a computational model conformed by some key essential parts of the adenylate energy system. Specifically, we have considered (I) the main synthesis process of ATP from ADP, (II) the main catalyzed phosphotransfer reaction for interconversion of ATP, ADP and AMP, (III) the enzymatic hydrolysis of ATP yielding ADP, and (IV) the enzymatic hydrolysis of ATP providing AMP. This leads to a dynamic metabolic model (with the form of a delayed differential system) in which the enzymatic rate equations and all the physiological kinetic parameters have been explicitly considered and experimentally tested in vitro. Our central hypothesis is that cells are characterized by changing energy dynamics (homeorhesis). The results show that the AEC presents stable transitions between steady states and periodic oscillations and, in agreement with experimental data these oscillations range within the narrow AEC window. Furthermore, the model shows sustained oscillations in the Gibbs free energy and in the total nucleotide pool. The present study provides a step forward towards the understanding of the fundamental principles and quantitative laws governing the adenylate energy system, which is a fundamental element for unveiling the dynamics of cellular life.
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Affiliation(s)
- Ildefonso M. De la Fuente
- Institute of Parasitology and Biomedicine “López-Neyra”, CSIC, Granada, Spain
- Department of Mathematics, University of the Basque Country UPV/EHU, Leioa, Spain
- Unit of Biophysics (CSIC, UPV/EHU), and Department of Biochemistry and Molecular Biology University of the Basque Country, Bilbao, Spain
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
| | - Jesús M. Cortés
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
- Ikerbasque: The Basque Foundation for Science, Bilbao, Basque Country, Spain
| | - Edelmira Valero
- Department of Physical Chemistry, School of Industrial Engineering, University of Castilla-La Mancha, Albacete, Spain
| | | | - Serafim Rodrigues
- School of Computing and Mathematics, University of Plymouth, Plymouth, United Kingdom
| | - Iker Malaina
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
- Department of Physiology, University of the Basque Country UPV/EHU, Bilbao, Spain
| | - Luis Martínez
- Department of Mathematics, University of the Basque Country UPV/EHU, Leioa, Spain
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
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Zatyka M, Da Silva Xavier G, Bellomo EA, Leadbeater W, Astuti D, Smith J, Michelangeli F, Rutter GA, Barrett TG. Sarco(endo)plasmic reticulum ATPase is a molecular partner of Wolfram syndrome 1 protein, which negatively regulates its expression. Hum Mol Genet 2014; 24:814-27. [PMID: 25274773 DOI: 10.1093/hmg/ddu499] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Wolfram syndrome is an autosomal recessive disorder characterized by neurodegeneration and diabetes mellitus. The gene responsible for the syndrome (WFS1) encodes an endoplasmic reticulum (ER)-resident transmembrane protein that is involved in the regulation of the unfolded protein response (UPR), intracellular ion homeostasis, cyclic adenosine monophosphate production and regulation of insulin biosynthesis and secretion. In this study, single cell Ca(2+) imaging with fura-2 and direct measurements of free cytosolic ATP concentration ([ATP]CYT) with adenovirally expressed luciferase confirmed a reduced and delayed rise in cytosolic free Ca(2+) concentration ([Ca(2+)]CYT), and additionally, diminished [ATP]CYT rises in response to elevated glucose concentrations in WFS1-depleted MIN6 cells. We also observed that sarco(endo)plasmic reticulum ATPase (SERCA) expression was elevated in several WFS1-depleted cell models and primary islets. We demonstrated a novel interaction between WFS1 and SERCA by co-immunoprecipitation in Cos7 cells and with endogenous proteins in human neuroblastoma cells. This interaction was reduced when cells were treated with the ER stress inducer dithiothreitol. Treatment of WFS1-depleted neuroblastoma cells with the proteasome inhibitor MG132 resulted in reduced accumulation of SERCA levels compared with wild-type cells. Together these results reveal a role for WFS1 in the negative regulation of SERCA and provide further insights into the function of WFS1 in calcium homeostasis.
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Affiliation(s)
| | - Gabriela Da Silva Xavier
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial Centre for Translation and Experimental Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Elisa A Bellomo
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial Centre for Translation and Experimental Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | | | - Dewi Astuti
- Department of Medical and Molecular Genetics
| | - Joel Smith
- Department of Medical and Molecular Genetics
| | - Frank Michelangeli
- School of Clinical and Experimental Medicine, The Medical School School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK and
| | - Guy A Rutter
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial Centre for Translation and Experimental Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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Hodson DJ, Tarasov AI, Gimeno Brias S, Mitchell RK, Johnston NR, Haghollahi S, Cane MC, Bugliani M, Marchetti P, Bosco D, Johnson PR, Hughes SJ, Rutter GA. Incretin-modulated beta cell energetics in intact islets of Langerhans. Mol Endocrinol 2014; 28:860-71. [PMID: 24766140 PMCID: PMC4042069 DOI: 10.1210/me.2014-1038] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/17/2014] [Indexed: 01/08/2023] Open
Abstract
Incretins such as glucagon-like peptide 1 (GLP-1) are released from the gut and potentiate insulin release in a glucose-dependent manner. Although this action is generally believed to hinge on cAMP and protein kinase A signaling, up-regulated beta cell intermediary metabolism may also play a role in incretin-stimulated insulin secretion. By employing recombinant probes to image ATP dynamically in situ within intact mouse and human islets, we sought to clarify the role of GLP-1-modulated energetics in beta cell function. Using these techniques, we show that GLP-1 engages a metabolically coupled subnetwork of beta cells to increase cytosolic ATP levels, an action independent of prevailing energy status. We further demonstrate that the effects of GLP-1 are accompanied by alterations in the mitochondrial inner membrane potential and, at elevated glucose concentration, depend upon GLP-1 receptor-directed calcium influx through voltage-dependent calcium channels. Lastly, and highlighting critical species differences, beta cells within mouse but not human islets respond coordinately to incretin stimulation. Together, these findings suggest that GLP-1 alters beta cell intermediary metabolism to influence ATP dynamics in a species-specific manner, and this may contribute to divergent regulation of the incretin-axis in rodents and man.
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Affiliation(s)
| | | | - Silvia Gimeno Brias
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Ryan K. Mitchell
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Natalie R. Johnston
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Shahab Haghollahi
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Matthew C. Cane
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Marco Bugliani
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Piero Marchetti
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Domenico Bosco
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Paul R. Johnson
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Stephen J. Hughes
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Guy A. Rutter
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine (D.J.H, A.I.T., S.G.B., R.K.M., N.R.J., S.H., M.C.C., G.A.R.), Imperial College London, London W12 0NN, United Kingdom; Department of Endocrinology and Metabolism (M.B., P.M.), University of Pisa, 56126 Pisa, Italy; Cell Isolation and Transplantation Center, Department of Surgery (D.B.), Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland; Oxford Centre for Diabetes, Endocrinology, & Metabolism (P.R.J., S.J.H.), University of Oxford, Oxford OX3 7LE, United Kingdom; NIHR Oxford Biomedical Research Centre (P.R.J., S.J.H.), Churchill Hospital, Oxford OX3 7LE, United Kingdom; and Nuffield Department of Surgical Sciences (P.R.J., S.J.H.), University of Oxford, Oxford OX3 9DU, United Kingdom
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Yi M, Yang S, Peng Z, Liu C, Li J, Zhong W, Yang R, Tan W. Two-Photon Graphene Oxide/Aptamer Nanosensing Conjugate for In Vitro or In Vivo Molecular Probing. Anal Chem 2014; 86:3548-54. [DOI: 10.1021/ac5000015] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mei Yi
- State
Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Sheng Yang
- State
Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Zanying Peng
- State
Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Changhui Liu
- State
Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Jishan Li
- State
Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Wenwan Zhong
- Department
of Chemistry, University of California-Riverside, Riverside, California 92521, United States
| | - Ronghua Yang
- State
Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Weihong Tan
- State
Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University, Changsha, 410082, China
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Riz M, Braun M, Pedersen MG. Mathematical modeling of heterogeneous electrophysiological responses in human β-cells. PLoS Comput Biol 2014; 10:e1003389. [PMID: 24391482 PMCID: PMC3879095 DOI: 10.1371/journal.pcbi.1003389] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/22/2013] [Indexed: 11/19/2022] Open
Abstract
Electrical activity plays a pivotal role in glucose-stimulated insulin secretion from pancreatic β-cells. Recent findings have shown that the electrophysiological characteristics of human β-cells differ from their rodent counterparts. We show that the electrophysiological responses in human β-cells to a range of ion channels antagonists are heterogeneous. In some cells, inhibition of small-conductance potassium currents has no effect on action potential firing, while it increases the firing frequency dramatically in other cells. Sodium channel block can sometimes reduce action potential amplitude, sometimes abolish electrical activity, and in some cells even change spiking electrical activity to rapid bursting. We show that, in contrast to L-type Ca2+-channels, P/Q-type Ca2+-currents are not necessary for action potential generation, and, surprisingly, a P/Q-type Ca2+-channel antagonist even accelerates action potential firing. By including SK-channels and Ca2+ dynamics in a previous mathematical model of electrical activity in human β-cells, we investigate the heterogeneous and nonintuitive electrophysiological responses to ion channel antagonists, and use our findings to obtain insight in previously published insulin secretion measurements. Using our model we also study paracrine signals, and simulate slow oscillations by adding a glycolytic oscillatory component to the electrophysiological model. The heterogenous electrophysiological responses in human β-cells must be taken into account for a deeper understanding of the mechanisms underlying insulin secretion in health and disease, and as shown here, the interdisciplinary combination of experiments and modeling increases our understanding of human β-cell physiology.
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Affiliation(s)
- Michela Riz
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Matthias Braun
- Alberta Diabetes Institute, Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Morten Gram Pedersen
- Department of Information Engineering, University of Padua, Padua, Italy
- * E-mail:
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Abstract
Mathematical modeling of the electrical activity of the pancreatic β-cell has been extremely important for understanding the cellular mechanisms involved in glucose-stimulated insulin secretion. Several models have been proposed over the last 30 y, growing in complexity as experimental evidence of the cellular mechanisms involved has become available. Almost all the models have been developed based on experimental data from rodents. However, given the many important differences between species, models of human β-cells have recently been developed. This review summarizes how modeling of β-cells has evolved, highlighting the proposed physiological mechanisms underlying β-cell electrical activity.
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Key Words
- ADP, adenosine diphosphate
- ATP, adenosine triphosphate
- CK, Chay-Keizer
- CRAC, calcium release-activated current
- Ca2+, calcium ions
- DOM, dual oscillator model
- ER, endoplasmic reticulum
- F6P, fructose-6-phosphate
- FBP, fructose-1,6-bisphosphate
- GLUT, glucose transporter
- GSIS, glucose-stimulated insulin secretion
- HERG, human eter à-go-go related gene
- IP3R, inositol-1,4,5-trisphosphate receptors
- KATP, ATP-sensitive K+ channels
- KCa, Ca2+-dependent K+ channels
- Kv, voltage-dependent K+ channels
- MCU, mitochondrial Ca2+ uniporter
- NCX, Na+/Ca2+ exchanger
- PFK, phosphofructokinase
- PMCA, plasma membrane Ca2+-ATPase
- ROS, reactive oxygen species
- RyR, ryanodine receptors
- SERCA, sarco-endoplasmic reticulum Ca2+-ATPase
- T2D, Type 2 Diabetes
- TCA, trycarboxylic acid cycle
- TRP, transient receptor potential
- VDCC, voltage-dependent Ca2+ channels
- Vm, membrane potential
- [ATP]i, cytosolic ATP
- [Ca2+]i, intracellular calcium concentration
- [Ca2+]m, mitochondrial calcium
- [Na+], Na+ concentration
- action potentials
- bursting
- cAMP, cyclic AMP
- calcium
- electrical activity
- ion channels
- mNCX, mitochondrial Na+/Ca2+ exchanger
- mathematical model
- β-cell
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Affiliation(s)
- Gerardo J Félix-Martínez
- Department of Electrical Engineering; Universidad
Autónoma Metropolitana-Iztapalapa; México, DF,
México
- Correspondence to: Gerardo J
Félix-Martínez;
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Tanaka T, Nagashima K, Inagaki N, Kioka H, Takashima S, Fukuoka H, Noji H, Kakizuka A, Imamura H. Glucose-stimulated single pancreatic islets sustain increased cytosolic ATP levels during initial Ca2+ influx and subsequent Ca2+ oscillations. J Biol Chem 2013; 289:2205-16. [PMID: 24302735 DOI: 10.1074/jbc.m113.499111] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In pancreatic islets, insulin secretion occurs via synchronous elevation of Ca(2+) levels throughout the islets during high glucose conditions. This Ca(2+) elevation has two phases: a quick increase, observed after the glucose stimulus, followed by prolonged oscillations. In these processes, the elevation of intracellular ATP levels generated from glucose is assumed to inhibit ATP-sensitive K(+) channels, leading to the depolarization of membranes, which in turn induces Ca(2+) elevation in the islets. However, little is known about the dynamics of intracellular ATP levels and their correlation with Ca(2+) levels in the islets in response to changing glucose levels. In this study, a genetically encoded fluorescent biosensor for ATP and a fluorescent Ca(2+) dye were employed to simultaneously monitor the dynamics of intracellular ATP and Ca(2+) levels, respectively, inside single isolated islets. We observed rapid increases in cytosolic and mitochondrial ATP levels after stimulation with glucose, as well as with methyl pyruvate or leucine/glutamine. High ATP levels were sustained as long as high glucose levels persisted. Inhibition of ATP production suppressed the initial Ca(2+) increase, suggesting that enhanced energy metabolism triggers the initial phase of Ca(2+) influx. On the other hand, cytosolic ATP levels did not fluctuate significantly with the Ca(2+) level in the subsequent oscillation phases. Importantly, Ca(2+) oscillations stopped immediately before ATP levels decreased significantly. These results might explain how food or glucose intake evokes insulin secretion and how the resulting decrease in plasma glucose levels leads to cessation of secretion.
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