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Ding Y, Yu XJ, Guo QX, Leng JH. Functional analysis of the novel mitochondrial tRNA Trp and tRNA Ser(AGY) variants associated with type 2 diabetes mellitus. World J Diabetes 2024; 15:1753-1763. [PMID: 39192858 PMCID: PMC11346085 DOI: 10.4239/wjd.v15.i8.1753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 05/09/2024] [Accepted: 06/18/2024] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND Mutations in mitochondrial tRNA (mt-tRNA) genes that result in mitochondrial dysfunction play important roles in type 2 diabetes mellitus (T2DM). We pre-viously reported a large Chinese pedigree with maternally inherited T2DM that harbors novel mt-tRNA Trp A5514G and tRNA Ser(AGY) C12237T variants, however, the effects of these mt-tRNA variants on T2DM progression are largely unknown. AIM To assess the potential pathogenicity of T2DM-associated m.A5514G and m.C12237T variants at genetic, molecular, and biochemical levels. METHODS Cytoplasmic hybrid (cybrid) cells carrying both m.A5514G and m.C12237T variants, and healthy control cells without these mitochondrial DNA (mtDNA) variants were generated using trans-mitochondrial technology. Mitochondrial features, including mt-tRNA steady-state level, levels of adenosine triphosphate (ATP), mitochondrial membrane potential (MMP), reactive oxygen species (ROS), mtDNA copy number, nicotinamide adenine dinucleotide (NAD+)/NADH ratio, enzymatic activities of respiratory chain complexes (RCCs), 8-hydroxy-deo-xyguanine (8-OhdG), malondialdehyde (MDA), and superoxide dismutase (SOD) were examined in cell lines with and without these mt-tRNA variants. RESULTS Compared with control cells, the m.A5514G variant caused an approximately 35% reduction in the steady-state level of mt-tRNA Trp (P < 0.0001); however, the m.C12237T variant did not affect the mt-tRNA Ser(AGY) steady-state level (P = 0.5849). Biochemical analysis revealed that cells with both m.A5514G and m.C12237T variants exhibited more severe mitochondrial dysfunctions and elevated oxidative stress than control cells: ATP, MMP, NAD+/NADH ratio, enzyme activities of RCCs and SOD levels were markedly decreased in mutant cells (P < 0.05 for all measures). By contrast, the levels of ROS, 8-OhdG and MDA were significantly increased (P < 0.05 for all measures), but mtDNA copy number was not affected by m.A5514G and m.C12237T variants (P = 0.5942). CONCLUSION The m.A5514G variant impaired mt-tRNA Trp metabolism, which subsequently caused mitochondrial dysfunction. The m.C12237T variant did not alter the steady-state level of mt-tRNA Ser(AGY), indicating that it may be a modifier of the m.A5514G variant. The m.A5514G variant may exacerbate the pathogenesis and progression of T2DM in this Chinese pedigree.
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Affiliation(s)
- Yu Ding
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou 310006, Zhejiang Province, China
| | - Xue-Jiao Yu
- Clinical Laboratory, Quzhou People’s Hospital, Quzhou 324000, Zhejiang Province, China
| | - Qin-Xian Guo
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou 310006, Zhejiang Province, China
| | - Jian-Hang Leng
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou 310006, Zhejiang Province, China
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2
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Wang H, Lu F, Tian Y, Zhang S, Han S, Fu Y, Li J, Feng P, Shi Z, Chen H, Hou H. Evaluation of toxicity of heated tobacco products aerosol and cigarette smoke to BEAS-2B cells based on 3D biomimetic chip model. Toxicol In Vitro 2024; 94:105708. [PMID: 37806364 DOI: 10.1016/j.tiv.2023.105708] [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: 05/23/2023] [Revised: 08/28/2023] [Accepted: 10/03/2023] [Indexed: 10/10/2023]
Abstract
It is still a controversial topic about evaluating whether heated tobacco products (HTP) really reduce harm, which involves the choice of an experimental model. Here, a three-dimensional (3D) biomimetic chip model was used to evaluate the toxicity of aerosols came from HTP and smoke produced by cigarettes (Cig). Based on cell-related experiments, we found that the toxicity of Cig smoke extract diluted four times was also much higher than that of undiluted HTP, showing higher oxidative stress response and cause mitochondrial dysfunction. Meanwhile, both tobacco products all affect the tricarboxylic acid cycle (TCA), which is manifested by a significant decrease in the mRNA expression of TCA key rate-limiting enzymes. Summarily, 3D Biomimetic chip technology can be used as an ideal model to evaluate HTP. It can provide important data for tobacco risk assessment when 3D chip model was used. Our experimental results showed that HTP may be less harmful than tobacco cigarettes, but it does show significant cytotoxicity with the increase of dose. Therefore, the potential clinical effects of HTP on targeted organs such as lung should be further studied.
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Affiliation(s)
- Hongjuan Wang
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China; Beijing Institute of Life Science and Technology, Beijing, China; Key Labortory of Tobacco Biological Effects and Biosynthesis, Beijing, China
| | - Fengjun Lu
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Yushan Tian
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China; Beijing Institute of Life Science and Technology, Beijing, China; Key Labortory of Tobacco Biological Effects and Biosynthesis, Beijing, China
| | - Sen Zhang
- Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering, Northwest University, Xi'an 710069, China
| | - Shulei Han
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China; Beijing Institute of Life Science and Technology, Beijing, China; Key Labortory of Tobacco Biological Effects and Biosynthesis, Beijing, China
| | - Yaning Fu
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China; Beijing Institute of Life Science and Technology, Beijing, China; Key Labortory of Tobacco Biological Effects and Biosynthesis, Beijing, China
| | - Jun Li
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China; Beijing Institute of Life Science and Technology, Beijing, China; Key Labortory of Tobacco Biological Effects and Biosynthesis, Beijing, China
| | - Pengxia Feng
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Zhihao Shi
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Huan Chen
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China; Beijing Institute of Life Science and Technology, Beijing, China; Key Labortory of Tobacco Biological Effects and Biosynthesis, Beijing, China.
| | - Hongwei Hou
- China National Tobacco Quality Supervision &Test Center, Zhengzhou, China; Key Laboratory of Tobacco Biological Effects, Zhengzhou, China; Beijing Institute of Life Science and Technology, Beijing, China; Key Labortory of Tobacco Biological Effects and Biosynthesis, Beijing, China.
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3
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Gelbach PE, Zheng D, Fraser SE, White KL, Graham NA, Finley SD. Kinetic and data-driven modeling of pancreatic β-cell central carbon metabolism and insulin secretion. PLoS Comput Biol 2022; 18:e1010555. [PMID: 36251711 PMCID: PMC9612825 DOI: 10.1371/journal.pcbi.1010555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/27/2022] [Accepted: 09/08/2022] [Indexed: 11/06/2022] Open
Abstract
Pancreatic β-cells respond to increased extracellular glucose levels by initiating a metabolic shift. That change in metabolism is part of the process of glucose-stimulated insulin secretion and is of particular interest in the context of diabetes. However, we do not fully understand how the coordinated changes in metabolic pathways and metabolite products influence insulin secretion. In this work, we apply systems biology approaches to develop a detailed kinetic model of the intracellular central carbon metabolic pathways in pancreatic β-cells upon stimulation with high levels of glucose. The model is calibrated to published metabolomics datasets for the INS1 823/13 cell line, accurately capturing the measured metabolite fold-changes. We first employed the calibrated mechanistic model to estimate the stimulated cell's fluxome. We then used the predicted network fluxes in a data-driven approach to build a partial least squares regression model. By developing the combined kinetic and data-driven modeling framework, we gain insights into the link between β-cell metabolism and glucose-stimulated insulin secretion. The combined modeling framework was used to predict the effects of common anti-diabetic pharmacological interventions on metabolite levels, flux through the metabolic network, and insulin secretion. Our simulations reveal targets that can be modulated to enhance insulin secretion. The model is a promising tool to contextualize and extend the usefulness of metabolomics data and to predict dynamics and metabolite levels that are difficult to measure in vitro. In addition, the modeling framework can be applied to identify, explain, and assess novel and clinically-relevant interventions that may be particularly valuable in diabetes treatment.
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Affiliation(s)
- Patrick E. Gelbach
- Department of Biomedical Engineering, USC, Los Angeles, California, United States of America
| | - Dongqing Zheng
- Mork Family Department of Chemical Engineering and Materials Science, USC, Los Angeles, California, United States of America
| | - Scott E. Fraser
- Translational Imaging Center, University of Southern California, Los Angeles, California, United States of America
| | - Kate L. White
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center, USC, Los Angeles, California, United States of America
| | - Nicholas A. Graham
- Mork Family Department of Chemical Engineering and Materials Science, USC, Los Angeles, California, United States of America
| | - Stacey D. Finley
- Department of Biomedical Engineering, USC, Los Angeles, California, United States of America
- Mork Family Department of Chemical Engineering and Materials Science, USC, Los Angeles, California, United States of America
- Department of Quantitative and Computational Biology, USC, Los Angeles, California, United States of America
- * E-mail:
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4
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Allen JG, Tessem JS. Ca 2+ Sensors Assemble: Function of the MCU Complex in the Pancreatic Beta Cell. Cells 2022; 11:cells11131993. [PMID: 35805078 PMCID: PMC9265474 DOI: 10.3390/cells11131993] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 12/05/2022] Open
Abstract
The Mitochondrial Calcium Uniporter Complex (MCU Complex) is essential for β-cell function due to its role in sustaining insulin secretion. The MCU complex regulates mitochondrial Ca2+ influx, which is necessary for increased ATP production following cellular glucose uptake, keeps the cell membrane K+ channels closed following initial insulin release, and ultimately results in sustained insulin granule exocytosis. Dysfunction in Ca2+ regulation results in an inability to sustain insulin secretion. This review defines the functions, structure, and mutations associated with the MCU complex members mitochondrial calcium uniporter protein (MCU), essential MCU regulator (EMRE), mitochondrial calcium uptake 1 (MICU1), mitochondrial calcium uptake 2 (MICU2), and mitochondrial calcium uptake 3 (MICU3) in the pancreatic β-cell. This review provides a framework for further evaluation of the MCU complex in β-cell function and insulin secretion.
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5
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Faraj N, Duinkerken BHP, Carroll EC, Giepmans BNG. Microscopic modulation and analysis of islets of Langerhans in living zebrafish larvae. FEBS Lett 2022; 596:2497-2512. [DOI: 10.1002/1873-3468.14411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/22/2022] [Accepted: 05/20/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Noura Faraj
- Department of Biomedical Sciences of Cells and Systems, University of Groningen University Medical Center Groningen Groningen 9713AV The Netherlands
| | - B. H. Peter Duinkerken
- Department of Biomedical Sciences of Cells and Systems, University of Groningen University Medical Center Groningen Groningen 9713AV The Netherlands
| | - Elizabeth C. Carroll
- Department of Imaging Physics Delft University of Technology Delft, 2628 CJ The Netherlands
| | - Ben N. G. Giepmans
- Department of Biomedical Sciences of Cells and Systems, University of Groningen University Medical Center Groningen Groningen 9713AV The Netherlands
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6
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Emfinger CH, de Klerk E, Schueler KL, Rabaglia ME, Stapleton DS, Simonett SP, Mitok KA, Wang Z, Liu X, Paulo JA, Yu Q, Cardone RL, Foster HR, Lewandowski SL, Perales JC, Kendziorski CM, Gygi SP, Kibbey RG, Keller MP, Hebrok M, Merrins MJ, Attie AD. β Cell-specific deletion of Zfp148 improves nutrient-stimulated β cell Ca2+ responses. JCI Insight 2022; 7:e154198. [PMID: 35603790 PMCID: PMC9220824 DOI: 10.1172/jci.insight.154198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 04/20/2022] [Indexed: 12/05/2022] Open
Abstract
Insulin secretion from pancreatic β cells is essential for glucose homeostasis. An insufficient response to the demand for insulin results in diabetes. We previously showed that β cell-specific deletion of Zfp148 (β-Zfp148KO) improves glucose tolerance and insulin secretion in mice. Here, we performed Ca2+ imaging of islets from β‑Zfp148KO and control mice fed both a chow and a Western-style diet. β-Zfp148KO islets demonstrated improved sensitivity and sustained Ca2+ oscillations in response to elevated glucose levels. β-Zfp148KO islets also exhibited elevated sensitivity to amino acid-induced Ca2+ influx under low glucose conditions, suggesting enhanced mitochondrial phosphoenolpyruvate-dependent (PEP-dependent), ATP-sensitive K+ channel closure, independent of glycolysis. RNA-Seq and proteomics of β-Zfp148KO islets revealed altered levels of enzymes involved in amino acid metabolism (specifically, SLC3A2, SLC7A8, GLS, GLS2, PSPH, PHGDH, and PSAT1) and intermediary metabolism (namely, GOT1 and PCK2), consistent with altered PEP cycling. In agreement with this, β-Zfp148KO islets displayed enhanced insulin secretion in response to l-glutamine and activation of glutamate dehydrogenase. Understanding pathways controlled by ZFP148 may provide promising strategies for improving β cell function that are robust to the metabolic challenge imposed by a Western diet.
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Affiliation(s)
| | | | - Kathryn L. Schueler
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mary E. Rabaglia
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Donnie S. Stapleton
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Shane P. Simonett
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kelly A. Mitok
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Ziyue Wang
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - Xinyue Liu
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Joao A. Paulo
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Qing Yu
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Rebecca L. Cardone
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, Connecticut, USA
| | - Hannah R. Foster
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sophie L. Lewandowski
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - José C. Perales
- Department of Physiological Sciences, School of Medicine, University of Barcelona, L’Hospitalet del Llobregat, Barcelona, Spain
| | - Christina M. Kendziorski
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Richard G. Kibbey
- Department of Internal Medicine (Endocrinology), Yale University, New Haven, Connecticut, USA
- Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut, USA
| | - Mark P. Keller
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | | | - Matthew J. Merrins
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin, USA
| | - Alan D. Attie
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
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7
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Shahroor MA, Lasorsa FM, Porcelli V, Dweikat I, Di Noia MA, Gur M, Agostino G, Shaag A, Rinaldi T, Gasparre G, Guerra F, Castegna A, Todisco S, Abu-Libdeh B, Elpeleg O, Palmieri L. PNC2 (SLC25A36) Deficiency Associated With the Hyperinsulinism/Hyperammonemia Syndrome. J Clin Endocrinol Metab 2022; 107:1346-1356. [PMID: 34971397 DOI: 10.1210/clinem/dgab932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT The hyperinsulinism/hyperammonemia (HI/HA) syndrome, the second-most common form of congenital hyperinsulinism, has been associated with dominant mutations in GLUD1, coding for the mitochondrial enzyme glutamate dehydrogenase, that increase enzyme activity by reducing its sensitivity to allosteric inhibition by GTP. OBJECTIVE To identify the underlying genetic etiology in 2 siblings who presented with the biochemical features of HI/HA syndrome but did not carry pathogenic variants in GLUD1, and to determine the functional impact of the newly identified mutation. METHODS The patients were investigated by whole exome sequencing. Yeast complementation studies and biochemical assays on the recombinant mutated protein were performed. The consequences of stable slc25a36 silencing in HeLa cells were also investigated. RESULTS A homozygous splice site variant was identified in solute carrier family 25, member 36 (SLC25A36), encoding the pyrimidine nucleotide carrier 2 (PNC2), a mitochondrial nucleotide carrier that transports pyrimidine as well as guanine nucleotides across the inner mitochondrial membrane. The mutation leads to a 26-aa in-frame deletion in the first repeat domain of the protein, which abolishes transport activity. Furthermore, knockdown of slc25a36 expression in HeLa cells caused a marked reduction in the mitochondrial GTP content, which likely leads to a hyperactivation of glutamate dehydrogenase in our patients. CONCLUSION We report for the first time a mutation in PNC2/SLC25A36 leading to HI/HA and provide functional evidence of the molecular mechanism responsible for this phenotype. Our findings underscore the importance of mitochondrial nucleotide metabolism and expand the role of mitochondrial transporters in insulin secretion.
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Affiliation(s)
- Maher A Shahroor
- Department of Pediatrics and Genetics, Al Makassed Hospital and Al-Quds University, 95908 Jerusalem, Palestine
- Department of Neonatology, Sunnybrook Health Sciences Center, University of Toronto, M4N 3M5 Toronto, Canada
| | - Francesco M Lasorsa
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, 70125 Bari, Italy
| | - Vito Porcelli
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Imad Dweikat
- Metabolic Unit, An-Najah National University, P467 Nablus, Palestine
| | - Maria Antonietta Di Noia
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Michal Gur
- Department of Genetics, Hadassah, Hebrew University Medical Center, 91120 Jerusalem, Israel
| | - Giulia Agostino
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Avraham Shaag
- Department of Genetics, Hadassah, Hebrew University Medical Center, 91120 Jerusalem, Israel
| | - Teresa Rinaldi
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Biology and Biotechnology "Charles Darwin", University of Rome La Sapienza, 00185 Rome, Italy
| | - Giuseppe Gasparre
- Department of Medical and Surgical Sciences (DIMEC), Unit of Medical Genetics and Center for Applied Biomedical Research (CRBA), University of Bologna, 40138 Bologna, Italy
| | - Flora Guerra
- Department of Medical and Surgical Sciences (DIMEC), Unit of Medical Genetics and Center for Applied Biomedical Research (CRBA), University of Bologna, 40138 Bologna, Italy
| | - Alessandra Castegna
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, 70125 Bari, Italy
| | - Simona Todisco
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Bassam Abu-Libdeh
- Department of Pediatrics and Genetics, Al Makassed Hospital and Al-Quds University, 95908 Jerusalem, Palestine
| | - Orly Elpeleg
- Department of Genetics, Hadassah, Hebrew University Medical Center, 91120 Jerusalem, Israel
| | - Luigi Palmieri
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, 70125 Bari, Italy
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8
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Verma G, Bowen A, Gheibi S, Hamilton A, Muthukumar S, Cataldo LR, Asplund O, Esguerra J, Karagiannopoulos A, Lyons C, Cowan E, Bellodi C, Prasad R, Fex M, Mulder H. Ribosomal biogenesis regulator DIMT1 controls β-cell protein synthesis, mitochondrial function, and insulin secretion. J Biol Chem 2022; 298:101692. [PMID: 35148993 PMCID: PMC8913306 DOI: 10.1016/j.jbc.2022.101692] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 01/24/2023] Open
Abstract
We previously reported that loss of mitochondrial transcription factor B1 (TFB1M) leads to mitochondrial dysfunction and is involved in the pathogenesis of type 2 diabetes (T2D). Whether defects in ribosomal processing impact mitochondrial function and could play a pathogenetic role in β-cells and T2D is not known. To this end, we explored expression and the functional role of dimethyladenosine transferase 1 homolog (DIMT1), a homolog of TFB1M and a ribosomal RNA (rRNA) methyltransferase implicated in the control of rRNA. Expression of DIMT1 was increased in human islets from T2D donors and correlated positively with expression of insulin mRNA, but negatively with insulin secretion. We show that silencing of DIMT1 in insulin-secreting cells impacted mitochondrial function, leading to lower expression of mitochondrial OXPHOS proteins, reduced oxygen consumption rate, dissipated mitochondrial membrane potential, and a slower rate of ATP production. In addition, the rate of protein synthesis was retarded upon DIMT1 deficiency. Consequently, we found that DIMT1 deficiency led to perturbed insulin secretion in rodent cell lines and islets, as well as in a human β-cell line. We observed defects in rRNA processing and reduced interactions between NIN1 (RPN12) binding protein 1 homolog (NOB-1) and pescadillo ribosomal biogenesis factor 1 (PES-1), critical ribosomal subunit RNA proteins, the dysfunction of which may play a part in disturbing protein synthesis in β-cells. In conclusion, DIMT1 deficiency perturbs protein synthesis, resulting in mitochondrial dysfunction and disrupted insulin secretion, both potential pathogenetic processes in T2D.
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Affiliation(s)
- Gaurav Verma
- Lund University Diabetes Centre, Lunds Universitet, Malmö, Sweden
| | - Alexander Bowen
- Lund University Diabetes Centre, Lunds Universitet, Malmö, Sweden
| | - Sevda Gheibi
- Lund University Diabetes Centre, Lunds Universitet, Malmö, Sweden
| | | | - Sowndarya Muthukumar
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, Lund, Sweden
| | | | - Olof Asplund
- Unit of Genomics, Diabetes and Endocrinology, Lund University Diabetes Centre, Malmö, Sweden
| | - Jonathan Esguerra
- Unit of Islet Cell Exocytosis, Lund University Diabetes Centre, Malmö, Sweden
| | | | - Claire Lyons
- Lund University Diabetes Centre, Lunds Universitet, Malmö, Sweden
| | - Elaine Cowan
- Lund University Diabetes Centre, Lunds Universitet, Malmö, Sweden
| | - Cristian Bellodi
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, Lund, Sweden
| | - Rashmi Prasad
- Unit of Genomics, Diabetes and Endocrinology, Lund University Diabetes Centre, Malmö, Sweden
| | - Malin Fex
- Lund University Diabetes Centre, Lunds Universitet, Malmö, Sweden
| | - Hindrik Mulder
- Lund University Diabetes Centre, Lunds Universitet, Malmö, Sweden.
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9
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Ntamo Y, Samodien E, Burger J, Muller N, Muller CJF, Chellan N. In vitro Characterization of Insulin-Producing β-Cell Spheroids. Front Cell Dev Biol 2021; 8:623889. [PMID: 33585464 PMCID: PMC7876261 DOI: 10.3389/fcell.2020.623889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/23/2020] [Indexed: 12/18/2022] Open
Abstract
Over the years, immortalized rodent β-cell lines such as RIN, HIT, MIN, βTC, and INS-1 have been used to investigate pancreatic β-cell physiology using conventional two-dimensional (2D) culture techniques. However, physical and physiological limitations inherent to 2D cell culture necessitates confirmatory follow up studies using sentient animals. Three-dimensional (3D) culture models are gaining popularity for their recapitulation of key features of in vivo organ physiology, and thus could pose as potential surrogates for animal experiments. In this study, we aimed to develop and characterize a rat insulinoma INS-1 3D spheroid model to compare with 2D monolayers of the same cell line. Ultrastructural verification was done by transmission electron microscopy and toluidine blue staining, which showed that both 2D monolayers and 3D spheroids contained highly granulated cells with ultrastructural features synonymous with mature pancreatic β-cells, with increased prominence of these features observed in 3D spheroids. Viability, as assessed by cellular ATP quantification, size profiling and glucose utilization, showed that our spheroids remained viable for the experimental period of 30 days, compared to the limiting 5-day passage period of INS-1 monolayers. In fact, increasing ATP content together with spheroid size was observed over time, without adverse changes in glucose utilization. Additionally, β-cell function, assessed by determining insulin and amylin secretion, showed that the 3D spheroids retained glucose sensing and insulin secretory capability, that was more acute when compared to 2D monolayer cultures. Thus, we were able to successfully demonstrate that our in vitro INS-1 β-cell 3D spheroid model exhibits in vivo tissue-like structural features with extended viability and lifespan. This offers enhanced predictive capacity of the model in the study of metabolic disease, β-cell pathophysiology and the potential treatment thereof.
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Affiliation(s)
- Yonela Ntamo
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa, South Africa
| | - Ebrahim Samodien
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa
| | - Joleen Burger
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nolan Muller
- National Health Laboratory Service, Anatomical Pathology, Tygerberg Hospital, Cape Town, South Africa
| | - Christo J F Muller
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nireshni Chellan
- Biomedical Research and Innovation Platform, South African Medical Research Council, Cape Town, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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Hu Y, Zhao H, Lu J, Xie D, Wang Q, Huang T, Xin H, Hisatome I, Yamamoto T, Wang W, Cheng J. High uric acid promotes dysfunction in pancreatic β cells by blocking IRS2/AKT signalling. Mol Cell Endocrinol 2021; 520:111070. [PMID: 33127482 DOI: 10.1016/j.mce.2020.111070] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 02/05/2023]
Abstract
Hyperuricaemia is a disorder of purine metabolism. Elevated serum uric acid is strongly associated with many diseases, including gout, abdominal obesity, insulin resistance, and cardiovascular and kidney disease. Our previous studies showed that high uric acid (HUA) induced insulin resistance in several peripheral organs, including the liver, myocardium and adipose tissue. However, whether HUA directly induces insulin resistance of pancreatic β cells, the only source of insulin in the body and also a sensitive insulin target, is unknown. In this study, pancreatic β cells pretreated with HUA showed impaired insulin expression/secretion, glucose uptake and the glycolytic pathway. RNA-seq revealed that HUA affected the biological processes of INS-1 cells broadly, including oxidoreduction coenzyme metabolic process, pyruvate metabolic process, and glycolytic process. In addition, HUA reduced mitochondrial membrane potential and increased the production of reactive oxygen species(ROS) in INS-1 cells. INS-1 cells pretreated with probenecid, an organic anion transporter inhibitor, protected INS-1 cells against HUA-induced insulin secretion decrease, Pretreatment with N-acetyl-L-cysteine(NAC), a globally used antioxidant, recovered HUA-decreased insulin secretion and glucose uptake by pancreatic β cells. Insulin-like growth factor 1 (IGF-1), the phosphatidylinositol 3-kinase (PI3K) activator, rescues HUA-decreased insulin secretion by re-activating AKT phosphorylation. Thus, HUA induce insulin resistance, impaired insulin secretion and glycolytic pathway of pancreatic ꞵ cell through IRS2/AKT pathway.
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Affiliation(s)
- Yaqiu Hu
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Hairong Zhao
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, Xiamen, Fujian, China
| | - Jiaming Lu
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, Xiamen, Fujian, China
| | - De Xie
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, Xiamen, Fujian, China
| | - Qiang Wang
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, Xiamen, Fujian, China
| | - Tianliang Huang
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Hancheng Xin
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Ichiro Hisatome
- Division of Regenerative Medicine and Therapeutics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, Yonago, Japan
| | - Tetsuya Yamamoto
- Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Wei Wang
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, Xiamen, Fujian, China.
| | - Jidong Cheng
- Department of Endocrinology, Xiang'an Hospital of Xiamen University, Xiamen, Fujian, China.
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11
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Mitochondrial gene expression in single cells shape pancreatic beta cells' sub-populations and explain variation in insulin pathway. Sci Rep 2021; 11:466. [PMID: 33432158 PMCID: PMC7801437 DOI: 10.1038/s41598-020-80334-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/21/2020] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial gene expression is pivotal to cell metabolism. Nevertheless, it is unknown whether it diverges within a given cell type. Here, we analysed single-cell RNA-seq experiments from human pancreatic alpha (N = 3471) and beta cells (N = 1989), as well as mouse beta cells (N = 1094). Cluster analysis revealed two distinct human beta cells populations, which diverged by mitochondrial (mtDNA) and nuclear DNA (nDNA)-encoded oxidative phosphorylation (OXPHOS) gene expression in healthy and diabetic individuals, and in newborn but not in adult mice. Insulin gene expression was elevated in beta cells with higher mtDNA gene expression in humans and in young mice. Such human beta cell populations also diverged in mitochondrial RNA mutational repertoire, and in their selective signature, thus implying the existence of two previously overlooked distinct and conserved beta cell populations. While applying our approach to human alpha cells, two sub-populations of cells were identified which diverged in mtDNA gene expression, yet these cellular populations did not consistently diverge in nDNA OXPHOS genes expression, nor did they correlate with the expression of glucagon, the hallmark of alpha cells. Thus, pancreatic beta cells within an individual are divided into distinct groups with unique metabolic-mitochondrial signature.
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12
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Oxidative Stress in Cytokine-Induced Dysfunction of the Pancreatic Beta Cell: Known Knowns and Known Unknowns. Metabolites 2020; 10:metabo10120480. [PMID: 33255484 PMCID: PMC7759861 DOI: 10.3390/metabo10120480] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/18/2020] [Accepted: 11/21/2020] [Indexed: 12/12/2022] Open
Abstract
Compelling evidence from earlier studies suggests that the pancreatic beta cell is inherently weak in its antioxidant defense mechanisms to face the burden of protecting itself against the increased intracellular oxidative stress following exposure to proinflammatory cytokines. Recent evidence implicates novel roles for nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Noxs) as contributors to the excessive intracellular oxidative stress and damage under metabolic stress conditions. This review highlights the existing evidence on the regulatory roles of at least three forms of Noxs, namely Nox1, Nox2, and Nox4, in the cascade of events leading to islet beta cell dysfunction, specifically under the duress of chronic exposure to cytokines. Potential crosstalk between key signaling pathways (e.g., inducible nitric oxide synthase [iNOS] and Noxs) in the generation and propagation of reactive molecules and metabolites leading to mitochondrial damage and cell apoptosis is discussed. Available data accrued in investigations involving small-molecule inhibitors and antioxidant protein expression methods as tools toward the prevention of cytokine-induced oxidative damage are reviewed. Lastly, current knowledge gaps in this field, and possible avenues for future research are highlighted.
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Mitochondrial Carriers Regulating Insulin Secretion Profiled in Human Islets upon Metabolic Stress. Biomolecules 2020; 10:biom10111543. [PMID: 33198243 PMCID: PMC7697104 DOI: 10.3390/biom10111543] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 11/10/2020] [Indexed: 12/27/2022] Open
Abstract
Chronic exposure of β-cells to nutrient-rich metabolic stress impairs mitochondrial metabolism and its coupling to insulin secretion. We exposed isolated human islets to different metabolic stresses for 3 days: 0.4 mM oleate or 0.4 mM palmitate at physiological 5.5 mM glucose (lipotoxicity), high 25 mM glucose (glucotoxicity), and high 25 mM glucose combined with 0.4 mM oleate and/or palmitate (glucolipotoxicity). Then, we profiled the mitochondrial carriers and associated genes with RNA-Seq. Diabetogenic conditions, and in particular glucotoxicity, increased expression of several mitochondrial solute carriers in human islets, such as the malate carrier DIC, the α-ketoglutarate-malate exchanger OGC, and the glutamate carrier GC1. Glucotoxicity also induced a general upregulation of the electron transport chain machinery, while palmitate largely counteracted this effect. Expression of different components of the TOM/TIM mitochondrial protein import system was increased by glucotoxicity, whereas glucolipotoxicity strongly upregulated its receptor subunit TOM70. Expression of the mitochondrial calcium uniporter MCU was essentially preserved by metabolic stresses. However, glucotoxicity altered expression of regulatory elements of calcium influx as well as the Na+/Ca2+ exchanger NCLX, which mediates calcium efflux. Overall, the expression profile of mitochondrial carriers and associated genes was modified by the different metabolic stresses exhibiting nutrient-specific signatures.
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14
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Prasun P. Role of mitochondria in pathogenesis of type 2 diabetes mellitus. J Diabetes Metab Disord 2020; 19:2017-2022. [PMID: 33520874 DOI: 10.1007/s40200-020-00679-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/28/2020] [Indexed: 01/09/2023]
Abstract
Type 2 diabetes mellitus (T2DM) is global health problem. An estimated 425 million people in the world had diabetes in 2017. It is a major cause of morbidity and mortality worldwide. Although, pathogenesis of T2DM and its complications have been focus of medical research for long, much remains to be learned. A better understanding of molecular pathogenesis is essential for more effective preventive and therapeutic interventions. Role of mitochondria in pathogenesis of metabolic problems such as obesity, metabolic syndrome, and T2DM is the focus of many recent research studies. Mitochondrial dysfunction contributes to the oxidative stress and systemic inflammation leading to insulin resistance (IR). Mitochondria are also essential for pancreatic beta cell insulin secretion. Hence, mitochondria are important players in the pathogenesis of T2DM. In this article, pathogenesis of T2DM is examined from a mitochondrial perspective.
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Affiliation(s)
- Pankaj Prasun
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place - Box 1497, New York, NY 10029 USA
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15
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Plecitá-Hlavatá L, Engstová H, Holendová B, Tauber J, Špaček T, Petrásková L, Křen V, Špačková J, Gotvaldová K, Ježek J, Dlasková A, Smolková K, Ježek P. Mitochondrial Superoxide Production Decreases on Glucose-Stimulated Insulin Secretion in Pancreatic β Cells Due to Decreasing Mitochondrial Matrix NADH/NAD + Ratio. Antioxid Redox Signal 2020; 33:789-815. [PMID: 32517485 PMCID: PMC7482716 DOI: 10.1089/ars.2019.7800] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/03/2020] [Accepted: 06/08/2020] [Indexed: 12/19/2022]
Abstract
Aims: Glucose-stimulated insulin secretion (GSIS) in pancreatic β cells was expected to enhance mitochondrial superoxide formation. Hence, we elucidated relevant redox equilibria. Results: Unexpectedly, INS-1E cells at transitions from 3 (11 mM; pancreatic islets from 5 mM) to 25 mM glucose decreased matrix superoxide release rates (MitoSOX Red monitoring validated by MitoB) and H2O2 (mitoHyPer, subtracting mitoSypHer emission). Novel double-channel fluorescence lifetime imaging, approximating free mitochondrial matrix NADHF, indicated its ∼20% decrease. Matrix NAD+F increased on GSIS, indicated by the FAD-emission lifetime decrease, reflecting higher quenching of FAD by NAD+F. The participation of pyruvate/malate and pyruvate/citrate redox shuttles, elevating cytosolic NADPHF (iNAP1 fluorescence monitoring) at the expense of matrix NADHF, was indicated, using citrate (2-oxoglutarate) carrier inhibitors and cytosolic malic enzyme silencing: All changes vanished on these manipulations. 13C-incorporation from 13C-L-glutamine into 13C-citrate reflected the pyruvate/isocitrate shuttle. Matrix NADPHF (iNAP3 monitored) decreased. With decreasing glucose, the suppressor of Complex III site Q electron leak (S3QEL) suppressor caused a higher Complex I IF site contribution, but a lower superoxide fraction ascribed to the Complex III site IIIQo. Thus, the diminished matrix NADHF/NAD+F decreased Complex I flavin site IF superoxide formation on GSIS. Innovation: Mutually validated methods showed decreasing superoxide release into the mitochondrial matrix in pancreatic β cells on GSIS, due to the decreasing matrix NADHF/NAD+F (NADPHF/NADP+F) at increasing cytosolic NADPHF levels. The developed innovative methods enable real-time NADH/NAD+ and NADPH/NADP+ monitoring in any distinct cell compartment. Conclusion: The export of reducing equivalents from mitochondria adjusts lower mitochondrial superoxide production on GSIS, but it does not prevent oxidative stress in pancreatic β cells.
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Affiliation(s)
- Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Engstová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Tauber
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Špaček
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lucie Petrásková
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vladimír Křen
- Laboratory of Biotransformation, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jitka Špačková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Klára Gotvaldová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Ježek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
- The Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
| | - Andrea Dlasková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Katarína Smolková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Ježek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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16
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Ferri G, Tesi M, Massarelli F, Marselli L, Marchetti P, Cardarelli F. Metabolic response of Insulinoma 1E cells to glucose stimulation studied by fluorescence lifetime imaging. FASEB Bioadv 2020; 2:409-418. [PMID: 32676581 PMCID: PMC7354695 DOI: 10.1096/fba.2020-00014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/01/2020] [Accepted: 05/21/2020] [Indexed: 01/02/2023] Open
Abstract
A cascade of highly regulated biochemical processes connects glucose stimulation to insulin secretion in specialized cells of mammalian pancreas, the β-cells. Given the importance of this process for systemic glucose homeostasis, noninvasive and fast strategies capable to monitor the response to glucose in living cells are highly desirable. Here, we use the phasor-based approach to Fluorescence Lifetime IMaging (FLIM) microscopy to quantify the ratio between protein-bound and free Nicotinamide adenine dinucleotide (phosphate) species in their reduced form (NAD(P)H), and the Insulinoma cell line INS-1E as a β-like cellular model. Phasor-FLIM analysis shows that the bound/free ratio of NAD(P)H species increases upon pulsed glucose stimulation. Such response is impaired by 48-hours preincubation of cells under hyperglycemic conditions. Phasor-FLIM concomitantly monitors the appearance of long-lifetime species (LLS) as characteristic products of hyperglycemia-induced oxidative stress.
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Affiliation(s)
| | - Marta Tesi
- Department of Clinical and Experimental MedicineIslet Cell LaboratoryUniversity of PisaPisaItaly
| | | | - Lorella Marselli
- Department of Clinical and Experimental MedicineIslet Cell LaboratoryUniversity of PisaPisaItaly
| | - Piero Marchetti
- Department of Clinical and Experimental MedicineIslet Cell LaboratoryUniversity of PisaPisaItaly
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17
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Brun T, Jiménez-Sánchez C, Madsen JGS, Hadadi N, Duhamel D, Bartley C, Oberhauser L, Trajkovski M, Mandrup S, Maechler P. AMPK Profiling in Rodent and Human Pancreatic Beta-Cells under Nutrient-Rich Metabolic Stress. Int J Mol Sci 2020; 21:ijms21113982. [PMID: 32492936 PMCID: PMC7312098 DOI: 10.3390/ijms21113982] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 12/13/2022] Open
Abstract
Chronic exposure of pancreatic β-cells to elevated nutrient levels impairs their function and potentially induces apoptosis. Like in other cell types, AMPK is activated in β-cells under conditions of nutrient deprivation, while little is known on AMPK responses to metabolic stresses. Here, we first reviewed recent studies on the role of AMPK activation in β-cells. Then, we investigated the expression profile of AMPK pathways in β-cells following metabolic stresses. INS-1E β-cells and human islets were exposed for 3 days to glucose (5.5–25 mM), palmitate or oleate (0.4 mM), and fructose (5.5 mM). Following these treatments, we analyzed transcript levels of INS-1E β-cells by qRT-PCR and of human islets by RNA-Seq; with a special focus on AMPK-associated genes, such as the AMPK catalytic subunits α1 (Prkaa1) and α2 (Prkaa2). AMPKα and pAMPKα were also evaluated at the protein level by immunoblotting. Chronic exposure to the different metabolic stresses, known to alter glucose-stimulated insulin secretion, did not change AMPK expression, either in insulinoma cells or in human islets. Expression profile of the six AMPK subunits was marginally modified by the different diabetogenic conditions. However, the expression of some upstream kinases and downstream AMPK targets, including K-ATP channel subunits, exhibited stress-specific signatures. Interestingly, at the protein level, chronic fructose treatment favored fasting-like phenotype in human islets, as witnessed by AMPK activation. Collectively, previously published and present data indicate that, in the β-cell, AMPK activation might be implicated in the pre-diabetic state, potentially as a protective mechanism.
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Affiliation(s)
- Thierry Brun
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
| | - Cecilia Jiménez-Sánchez
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
| | - Jesper Grud Skat Madsen
- Functional Genomics and Metabolism Research Unit, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark; (J.G.S.M.); (S.M.)
| | - Noushin Hadadi
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
| | - Dominique Duhamel
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
| | - Clarissa Bartley
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
| | - Lucie Oberhauser
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
| | - Mirko Trajkovski
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
| | - Susanne Mandrup
- Functional Genomics and Metabolism Research Unit, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark; (J.G.S.M.); (S.M.)
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism & Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland; (T.B.); (C.J.-S.); (N.H.); (D.D.); (C.B.); (L.O.); (M.T.)
- Correspondence:
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18
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Esch N, Jo S, Moore M, Alejandro EU. Nutrient Sensor mTOR and OGT: Orchestrators of Organelle Homeostasis in Pancreatic β-Cells. J Diabetes Res 2020; 2020:8872639. [PMID: 33457426 PMCID: PMC7787834 DOI: 10.1155/2020/8872639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/06/2020] [Accepted: 11/24/2020] [Indexed: 02/08/2023] Open
Abstract
The purpose of this review is to integrate the role of nutrient-sensing pathways into β-cell organelle dysfunction prompted by nutrient excess during type 2 diabetes (T2D). T2D encompasses chronic hyperglycemia, hyperlipidemia, and inflammation, which each contribute to β-cell failure. These factors can disrupt the function of critical β-cell organelles, namely, the ER, mitochondria, lysosomes, and autophagosomes. Dysfunctional organelles cause defects in insulin synthesis and secretion and activate apoptotic pathways if homeostasis is not restored. In this review, we will focus on mTORC1 and OGT, two major anabolic nutrient sensors with important roles in β-cell physiology. Though acute stimulation of these sensors frequently improves β-cell function and promotes adaptation to cell stress, chronic and sustained activity disturbs organelle homeostasis. mTORC1 and OGT regulate organelle function by influencing the expression and activities of key proteins, enzymes, and transcription factors, as well as by modulating autophagy to influence clearance of defective organelles. In addition, mTORC1 and OGT activity influence islet inflammation during T2D, which can further disrupt organelle and β-cell function. Therapies for T2D that fine-tune the activity of these nutrient sensors have yet to be developed, but the important role of mTORC1 and OGT in organelle homeostasis makes them promising targets to improve β-cell function and survival.
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Affiliation(s)
- Nicholas Esch
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Seokwon Jo
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mackenzie Moore
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Surgery, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Emilyn U. Alejandro
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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19
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Kang GG, Francis N, Hill R, Waters D, Blanchard C, Santhakumar AB. Dietary Polyphenols and Gene Expression in Molecular Pathways Associated with Type 2 Diabetes Mellitus: A Review. Int J Mol Sci 2019; 21:ijms21010140. [PMID: 31878222 PMCID: PMC6981492 DOI: 10.3390/ijms21010140] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/13/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder with various contributing factors including genetics, epigenetics, environment and lifestyle such as diet. The hallmarks of T2DM are insulin deficiency (also referred to as β-cell dysfunction) and insulin resistance. Robust evidence suggests that the major mechanism driving impaired β-cell function and insulin signalling is through the action of intracellular reactive oxygen species (ROS)-induced stress. Chronic high blood glucose (hyperglycaemia) and hyperlipidaemia appear to be the primary activators of these pathways. Reactive oxygen species can disrupt intracellular signalling pathways, thereby dysregulating the expression of genes associated with insulin secretion and signalling. Plant-based diets, containing phenolic compounds, have been shown to exhibit remedial benefits by ameliorating insulin secretion and insulin resistance. The literature also provides evidence that polyphenol-rich diets can modulate the expression of genes involved in insulin secretion, insulin signalling, and liver gluconeogenesis pathways. However, whether various polyphenols and phenolic compounds can target specific cellular signalling pathways involved in the pathogenesis of T2DM has not been elucidated. This review aims to evaluate the modulating effects of various polyphenols and phenolic compounds on genes involved in cellular signalling pathways (both in vitro and in vivo from human, animal and cell models) leading to the pathogenesis of T2DM.
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Affiliation(s)
- Gideon Gatluak Kang
- Australian Research Council (ARC) Industrial Transformation Training Centre (ITTC) for Functional Grains, Graham Centre for Agricultural Innovation, Wagga Wagga, NSW 2650, Australia; (G.G.K.); (N.F.); (D.W.); (C.B.)
- School of Biomedical Sciences, Charles Sturt University, NSW 2650, Australia;
| | - Nidhish Francis
- Australian Research Council (ARC) Industrial Transformation Training Centre (ITTC) for Functional Grains, Graham Centre for Agricultural Innovation, Wagga Wagga, NSW 2650, Australia; (G.G.K.); (N.F.); (D.W.); (C.B.)
- School of Animal and Veterinary Sciences, Charles Sturt University, NSW 2650, Australia
| | - Rodney Hill
- School of Biomedical Sciences, Charles Sturt University, NSW 2650, Australia;
| | - Daniel Waters
- Australian Research Council (ARC) Industrial Transformation Training Centre (ITTC) for Functional Grains, Graham Centre for Agricultural Innovation, Wagga Wagga, NSW 2650, Australia; (G.G.K.); (N.F.); (D.W.); (C.B.)
- School of Biomedical Sciences, Charles Sturt University, NSW 2650, Australia;
| | - Christopher Blanchard
- Australian Research Council (ARC) Industrial Transformation Training Centre (ITTC) for Functional Grains, Graham Centre for Agricultural Innovation, Wagga Wagga, NSW 2650, Australia; (G.G.K.); (N.F.); (D.W.); (C.B.)
- School of Biomedical Sciences, Charles Sturt University, NSW 2650, Australia;
| | - Abishek Bommannan Santhakumar
- Australian Research Council (ARC) Industrial Transformation Training Centre (ITTC) for Functional Grains, Graham Centre for Agricultural Innovation, Wagga Wagga, NSW 2650, Australia; (G.G.K.); (N.F.); (D.W.); (C.B.)
- School of Biomedical Sciences, Charles Sturt University, NSW 2650, Australia;
- Correspondence: ; Tel.: +61-2-6933-2678
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20
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Abstract
PURPOSE OF REVIEW This review summarizes the alterations in the β-cell observed in type 2 diabetes (T2D), focusing on changes in β-cell identity and mass and changes associated with metabolism and intracellular signaling. RECENT FINDINGS In the setting of T2D, β-cells undergo changes in gene expression, reverting to a more immature state and in some cases transdifferentiating into other islet cell types. Alleviation of metabolic stress, ER stress, and maladaptive prostaglandin signaling could improve β-cell function and survival. The β-cell defects leading to T2D likely differ in different individuals and include variations in β-cell mass, development, β-cell expansion, responses to ER and oxidative stress, insulin production and secretion, and intracellular signaling pathways. The recent recognition that some β-cells undergo dedifferentiation without dying in T2D suggests strategies to revive these cells and rejuvenate their functionality.
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Affiliation(s)
- Ashley A Christensen
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Maureen Gannon
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA.
- Department of Medicine, Vanderbilt University Medical Center, 2213 Garland Ave, MRB IV 7465, Nashville, TN, 37232, USA.
- Department of Veterans Affairs, Tennessee Valley Health Authority, Nashville, TN, 37232, USA.
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA.
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Bartley C, Brun T, Oberhauser L, Grimaldi M, Molica F, Kwak BR, Bosco D, Chanson M, Maechler P. Chronic fructose renders pancreatic β-cells hyper-responsive to glucose-stimulated insulin secretion through extracellular ATP signaling. Am J Physiol Endocrinol Metab 2019; 317:E25-E41. [PMID: 30912960 DOI: 10.1152/ajpendo.00456.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Fructose is widely used as a sweetener in processed food and is also associated with metabolic disorders, such as obesity. However, the underlying cellular mechanisms remain unclear, in particular, regarding the pancreatic β-cell. Here, we investigated the effects of chronic exposure to fructose on the function of insulinoma cells and isolated mouse and human pancreatic islets. Although fructose per se did not acutely stimulate insulin exocytosis, our data show that chronic fructose rendered rodent and human β-cells hyper-responsive to intermediate physiological glucose concentrations. Fructose exposure reduced intracellular ATP levels without affecting mitochondrial function, induced AMP-activated protein kinase activation, and favored ATP release from the β-cells upon acute glucose stimulation. The resulting increase in extracellular ATP, mediated by pannexin1 (Panx1) channels, activated the calcium-mobilizer P2Y purinergic receptors. Immunodetection revealed the presence of both Panx1 channels and P2Y1 receptors in β-cells. Addition of an ectonucleotidase inhibitor or P2Y1 agonists to naïve β-cells potentiated insulin secretion stimulated by intermediate glucose, mimicking the fructose treatment. Conversely, the P2Y1 antagonist and Panx1 inhibitor reversed the effects of fructose, as confirmed using Panx1-null islets and by the clearance of extracellular ATP by apyrase. These results reveal an important function of ATP signaling in pancreatic β-cells mediating fructose-induced hyper-responsiveness.
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Affiliation(s)
- Clarissa Bartley
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Thierry Brun
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Lucie Oberhauser
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Mariagrazia Grimaldi
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Filippo Molica
- Department of Pathology and Immunology, University of Geneva Medical Center , Geneva , Switzerland
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva Medical Center , Geneva , Switzerland
- Division of Cardiology, University of Geneva Medical Center , Geneva , Switzerland
| | - Domenico Bosco
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
- Department of Surgery, Cell Isolation and Transplantation Center, Geneva University Hospital , Geneva , Switzerland
| | - Marc Chanson
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Department of Pediatrics, Geneva University Hospital , Geneva , Switzerland
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
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22
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Haythorne E, Rohm M, van de Bunt M, Brereton MF, Tarasov AI, Blacker TS, Sachse G, Silva Dos Santos M, Terron Exposito R, Davis S, Baba O, Fischer R, Duchen MR, Rorsman P, MacRae JI, Ashcroft FM. Diabetes causes marked inhibition of mitochondrial metabolism in pancreatic β-cells. Nat Commun 2019; 10:2474. [PMID: 31171772 PMCID: PMC6554411 DOI: 10.1038/s41467-019-10189-x] [Citation(s) in RCA: 202] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 04/12/2019] [Indexed: 12/21/2022] Open
Abstract
Diabetes is a global health problem caused primarily by the inability of pancreatic β-cells to secrete adequate levels of insulin. The molecular mechanisms underlying the progressive failure of β-cells to respond to glucose in type-2 diabetes remain unresolved. Using a combination of transcriptomics and proteomics, we find significant dysregulation of major metabolic pathways in islets of diabetic βV59M mice, a non-obese, eulipidaemic diabetes model. Multiple genes/proteins involved in glycolysis/gluconeogenesis are upregulated, whereas those involved in oxidative phosphorylation are downregulated. In isolated islets, glucose-induced increases in NADH and ATP are impaired and both oxidative and glycolytic glucose metabolism are reduced. INS-1 β-cells cultured chronically at high glucose show similar changes in protein expression and reduced glucose-stimulated oxygen consumption: targeted metabolomics reveals impaired metabolism. These data indicate hyperglycaemia induces metabolic changes in β-cells that markedly reduce mitochondrial metabolism and ATP synthesis. We propose this underlies the progressive failure of β-cells in diabetes.
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Affiliation(s)
- Elizabeth Haythorne
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, OX1 3PT, UK
| | - Maria Rohm
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, OX1 3PT, UK
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, 85764, Germany
| | - Martijn van de Bunt
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7EL, UK
- Department of Bioinformatics and Data Mining, Novo Nordisk A/S, Måløv, 2760, Denmark
| | - Melissa F Brereton
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, OX1 3PT, UK
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7EL, UK
| | - Thomas S Blacker
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Gregor Sachse
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, OX1 3PT, UK
| | | | - Raul Terron Exposito
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, OX1 3PT, UK
| | - Simon Davis
- Discovery Proteomics Facility, Target Discovery Institute, University of Oxford, Oxford, OX3 7FZ, UK
| | - Otto Baba
- Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8504, Japan
| | - Roman Fischer
- Discovery Proteomics Facility, Target Discovery Institute, University of Oxford, Oxford, OX3 7FZ, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7EL, UK
- Metabolic Research, Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Göteborg, Box 433, 40530, Göteborg, Sweden
| | - James I MacRae
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Frances M Ashcroft
- Department of Physiology, Anatomy and Genetics and OXION, University of Oxford, Oxford, OX1 3PT, UK.
- Metabolic Research, Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Göteborg, Box 433, 40530, Göteborg, Sweden.
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23
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Hou L, Tang S, Wu BJ, Ong KL, Westerterp M, Barter PJ, Cochran BJ, Tabet F, Rye KA. Apolipoprotein A-I improves pancreatic β-cell function independent of the ATP-binding cassette transporters ABCA1 and ABCG1. FASEB J 2019; 33:8479-8489. [PMID: 30970222 DOI: 10.1096/fj.201802512rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Apolipoprotein A-I (apoA-I), the main protein constituent of HDLs, increases insulin synthesis and insulin secretion in pancreatic β cells. ApoA-I also accepts cholesterol that effluxes from cells expressing ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1). Mice with conditional deletion of ABCA1 and ABCG1 in β cells [β-double knockout (DKO) mice] have increased islet cholesterol levels and reduced glucose-stimulated insulin secretion (GSIS). The project asks whether metabolic pathways are dysregulated in β-DKO mouse islets and whether this can be corrected, and GSIS improved, by treatment with apoA-I. β-DKO mice were treated with apoA-I or PBS, and islets were isolated for determination of GSIS. Total RNA was extracted from β-DKO and control mouse islets for microarray analysis. Metabolic pathways were interrogated by functional enrichment analysis. ApoA-I treatment improved GSIS in β-DKO but not control mouse islets. Plasma lipid and lipoprotein levels and islet cholesterol levels were also unaffected by treatment with apoA-I. Cholesterol metabolism, glucose metabolism, and inflammation pathways were dysregulated in β-DKO mouse islets. This was not corrected by treatment with apoA-I. In summary, apoA-I treatment improves GSIS by a cholesterol-independent mechanism, but it does not correct metabolic dysregulation in β-DKO mouse islets.-Hou, L., Tang, S., Wu, B. J., Ong, K.-L., Westerterp, M., Barter, P. J., Cochran, B. J., Tabet, F., Rye, K.-A. Apolipoprotein A-I improves pancreatic β-cell function independent of the ATP-binding cassette transporters ABCA1 and ABCG1.
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Affiliation(s)
- Liming Hou
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Shudi Tang
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Ben J Wu
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Kwok-Leung Ong
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Marit Westerterp
- Section Molecular Genetics, Department of Pediatrics, University of Groningen-University Medical Center Groningen, Groningen, The Netherlands
| | - Philip J Barter
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Blake J Cochran
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Fatiha Tabet
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
| | - Kerry-Anne Rye
- Lipid Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, Sydney, New South Wales, Australia
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24
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Li Z, Liu H, Niu Z, Zhong W, Xue M, Wang J, Yang F, Zhou Y, Zhou Y, Xu T, Hou J. Temporal Proteomic Analysis of Pancreatic β-Cells in Response to Lipotoxicity and Glucolipotoxicity. Mol Cell Proteomics 2018; 17:2119-2131. [PMID: 30082485 DOI: 10.1074/mcp.ra118.000698] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 08/03/2018] [Indexed: 12/12/2022] Open
Abstract
Chronic hyperlipidemia causes the dysfunction of pancreatic β-cells, such as apoptosis and impaired insulin secretion, which are aggravated in the presence of hyperglycemia. The underlying mechanisms, such as endoplasmic reticulum (ER) stress, oxidative stress and metabolic disorders, have been reported before; however, the time sequence of these molecular events is not fully understood. Here, using isobaric labeling-based mass spectrometry, we investigated the dynamic proteomes of INS-1 cells exposed to high palmitate in the absence and presence of high glucose. Using bioinformatics analysis of differentially expressed proteins, including the time-course expression pattern, protein-protein interaction, gene set enrichment and KEGG pathway analysis, we analyzed the dynamic features of previously reported and newly identified lipotoxicity- and glucolipotoxicity-related molecular events in more detail. Our temporal data highlight cholesterol metabolism occurring at 4 h, earlier than fatty acid metabolism that started at 8 h and likely acting as an early toxic event highly associated with ER stress induced by palmitate. Interestingly, we found that the proliferation of INS-1 cells was significantly increased at 48 h by combined treatment of palmitate and glucose. Moreover, benefit from the time-course quantitative data, we identified and validated two new molecular targets: Setd8 for cell replication and Rhob for apoptosis, demonstrating that our temporal dataset serves as a valuable resource to identify potential candidates for mechanistic studies of lipotoxicity and glucolipotoxicity in pancreatic β-cells.
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Affiliation(s)
- Zonghong Li
- From the ‡National Laboratory of Biomacramolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,§Jilin Province Key Laboratory on Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun, 130024, China
| | - Hongyang Liu
- From the ‡National Laboratory of Biomacramolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,‖Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhangjing Niu
- From the ‡National Laboratory of Biomacramolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,‖Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wen Zhong
- ***College of Life Science and Technology, HuaZhong University of Science and Technology, Wuhan 430074, China
| | - Miaomiao Xue
- From the ‡National Laboratory of Biomacramolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,¶College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jifeng Wang
- ‡‡Laboratory of Protein and Peptide Pharmaceuticals and Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Fuquan Yang
- ‡‡Laboratory of Protein and Peptide Pharmaceuticals and Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,¶College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yue Zhou
- §§ThermoFisher Scientific, Building 6, No. 27, Xin Jinqiao Rd, Pudong, Shanghai, 201206, China
| | - Yifa Zhou
- §Jilin Province Key Laboratory on Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun, 130024, China;
| | - Tao Xu
- From the ‡National Laboratory of Biomacramolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; .,¶College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junjie Hou
- From the ‡National Laboratory of Biomacramolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China;
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25
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Energy depletion and not ROS formation is a crucial step of glucolipotoxicity (GLTx) in pancreatic beta cells. Pflugers Arch 2017; 470:537-547. [PMID: 29218453 DOI: 10.1007/s00424-017-2094-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 11/30/2017] [Indexed: 12/27/2022]
Abstract
We have shown previously that genetic or pharmacological deletion of KATP channels protect against beta cell dysfunction induced by reactive oxygen species (ROS). Since it is assumed that glucolipotoxicity (GLTx) causes ROS production, we aimed to evaluate whether suppression of KATP channel activity can also prevent beta cell damage evoked by GLTx. We used an in vitro model of GLTx and measured distinct parameters of stimulus-secretion coupling. GLTx gradually induced disturbances of Ca2+ oscillations over 3 days. This impairment in Ca2+ dynamics was partially reversed in beta cells without functional KATP channels (SUR1-/-) and by the sulfonylurea gliclazide but not by tolbutamide. By contrast, the GLTx-induced suppression of glucose-induced insulin secretion could not be rescued by decreased KATP channel activity pointing to a direct interaction of GLTx with the secretory capacity. Accordingly, GLTx also suppressed KCl-induced insulin secretion. GLTx was not accompanied by decisively increased ROS production or enhanced apoptosis. Insulin content of beta cells was markedly reduced by GLTx, an effect not prevented by gliclazide. Since GLTx markedly diminished the mitochondrial membrane potential and cellular ATP content, lack of ATP is assumed to decrease insulin biosynthesis. The deleterious effect of GLTx is therefore caused by direct interference with the secretory capacity whereby reduction of insulin content is one important parameter. These findings deepen our understanding how GLTx damages beta cells and reveal that GLTx is disconnected from ROS formation, a notion important for targeting beta cells in the treatment of diabetes. Overall, GLTx-induced energy depletion may be a primary step in the cascade of events leading to loss of beta cell function in type-2 diabetes mellitus.
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26
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Upregulation of UCP2 in beta-cells confers partial protection against both oxidative stress and glucotoxicity. Redox Biol 2017; 13:541-549. [PMID: 28755631 PMCID: PMC5537434 DOI: 10.1016/j.redox.2017.07.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 01/09/2023] Open
Abstract
Deterioration of pancreatic beta-cells plays a critical role in the development of type 2 diabetes. Among the various stressors contributing to these deleterious effects, glucotoxicity and superoxides have been proposed as major players. In this context, the mitochondrial uncoupling protein UCP2 is regularly associated with the stress response. In the present study, we tested the effects of UCP2 upregulation in mouse islets with beta-cell specific overexpression of UCP2 (RIP-UCP2). Islets were subjected to both chronic glucotoxicity (7 days at 30 mM glucose) and acute oxidative stress (200 µM H2O2 for 10 min). Increased UCP2 expression did not alter mitochondrial potential and ATP generation but protected against glucotoxic effects. Glucose-stimulated insulin secretion was altered by both glucotoxicity and oxidative stress, in particular through higher basal insulin release at non-stimulatory glucose concentrations. The secretory response to glucose stimulation was partially preserved in beta-cells overexpressing UCP2. The higher rate of cell death induced by chronic high glucose exposure was lower in RIP-UCP2 islets. Finally, superoxide production was reduced by high glucose, both under acute and chronic conditions, and not modified by UCP2 overexpression. In conclusion, upregulation of UCP2 conferred protective effects to the stressed beta-cell through mechanisms not directly associated with superoxide production. UCP2 upregulation protects pancreatic ß-cells against glucotoxicity. High glucose reduces superoxide production in pancreatic islets. UCP2 upregulation does not change superoxide production. UCP2 upregulation protects ß-cells against oxidative stress.
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27
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Abstract
BACKGROUND Environmental and lifestyle changes, in addition to the ageing of populations, are generally believed to account for the rapid global increase in type 2 diabetes prevalence and incidence in recent decades. DISCUSSION In this review, we present a comprehensive overview of factors contributing to diabetes risk, including aspects of diet quality and quantity, little physical activity, increased monitor viewing time or sitting in general, exposure to noise or fine dust, short or disturbed sleep, smoking, stress and depression, and a low socioeconomic status. In general, these factors promote an increase in body mass index. Since loss of β-cell function is the ultimate cause of developing overt type 2 diabetes, environmental and lifestyle changes must have resulted in a higher risk of β-cell damage in those at genetic risk. Multiple mechanistic pathways may come into play. CONCLUSIONS Strategies of diabetes prevention should aim at promoting a 'diabetes-protective lifestyle' whilst simultaneously enhancing the resistance of the human organism to pro-diabetic environmental and lifestyle factors. More research on diabetes-protective mechanisms seems warranted.
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28
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Kolb H, Martin S. Environmental/lifestyle factors in the pathogenesis and prevention of type 2 diabetes. BMC Med 2017; 15:131. [PMID: 28720102 PMCID: PMC5516328 DOI: 10.1186/s12916-017-0901-x] [Citation(s) in RCA: 358] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/23/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Environmental and lifestyle changes, in addition to the ageing of populations, are generally believed to account for the rapid global increase in type 2 diabetes prevalence and incidence in recent decades. DISCUSSION In this review, we present a comprehensive overview of factors contributing to diabetes risk, including aspects of diet quality and quantity, little physical activity, increased monitor viewing time or sitting in general, exposure to noise or fine dust, short or disturbed sleep, smoking, stress and depression, and a low socioeconomic status. In general, these factors promote an increase in body mass index. Since loss of β-cell function is the ultimate cause of developing overt type 2 diabetes, environmental and lifestyle changes must have resulted in a higher risk of β-cell damage in those at genetic risk. Multiple mechanistic pathways may come into play. CONCLUSIONS Strategies of diabetes prevention should aim at promoting a 'diabetes-protective lifestyle' whilst simultaneously enhancing the resistance of the human organism to pro-diabetic environmental and lifestyle factors. More research on diabetes-protective mechanisms seems warranted.
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Affiliation(s)
- Hubert Kolb
- Faculty of Medicine, University of Duesseldorf, Duesseldorf, Germany. .,West-German Centre of Diabetes and Health, Duesseldorf Catholic Hospital Group, Hohensandweg 37, 40591, Duesseldorf, Germany.
| | - Stephan Martin
- Faculty of Medicine, University of Duesseldorf, Duesseldorf, Germany.,West-German Centre of Diabetes and Health, Duesseldorf Catholic Hospital Group, Hohensandweg 37, 40591, Duesseldorf, Germany
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29
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Ashcroft FM, Rohm M, Clark A, Brereton MF. Is Type 2 Diabetes a Glycogen Storage Disease of Pancreatic β Cells? Cell Metab 2017; 26:17-23. [PMID: 28683284 PMCID: PMC5890904 DOI: 10.1016/j.cmet.2017.05.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/24/2017] [Accepted: 05/24/2017] [Indexed: 11/17/2022]
Abstract
Elevated plasma glucose leads to pancreatic β cell dysfunction and death in type 2 diabetes. Glycogen accumulation, due to impaired metabolism, contributes to this "glucotoxicity" via dysregulated biochemical pathways promoting β cell dysfunction. Here, we review emerging data, and re-examine published findings, on the role of glycogen in β cells in normoglycemia and in diabetes.
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Affiliation(s)
- Frances M Ashcroft
- Department of Physiology, Anatomy, and Genetics and OXION, University of Oxford, Parks Road, Oxford OX1 3PT, UK.
| | - Maria Rohm
- Department of Physiology, Anatomy, and Genetics and OXION, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Melissa F Brereton
- Department of Physiology, Anatomy, and Genetics and OXION, University of Oxford, Parks Road, Oxford OX1 3PT, UK
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30
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Tesauro C, Ferrando B, Ma X, Jepsen ML, Ivarsen AKR, Frøhlich R, Stevnsner T, Knudsen BR, Ho YP. Isolation of functional mitochondria by inertial microfluidics – a new method to sort intracellular organelles from a small scale biological sample. RSC Adv 2017. [DOI: 10.1039/c7ra03384b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Isolation of subcellular fractions from a limited amount of clinical sample is imperative for the continuous advancement of biological and clinical research.
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Affiliation(s)
- C. Tesauro
- Aarhus University
- Department of Molecular Biology and Genetics
- Aarhus
- Denmark
| | - B. Ferrando
- Aarhus University
- Department of Molecular Biology and Genetics
- Aarhus
- Denmark
| | - X. Ma
- Aarhus University
- Department of Molecular Biology and Genetics
- Aarhus
- Denmark
- Aarhus University
| | - M. L. Jepsen
- Aarhus University
- Department of Molecular Biology and Genetics
- Aarhus
- Denmark
- Aarhus University
| | - A. K. R. Ivarsen
- Aarhus University
- Interdisciplinary Nanoscience Center (iNANO)
- Aarhus
- Denmark
- Aarhus University
| | - R. Frøhlich
- Aarhus University
- Department of Molecular Biology and Genetics
- Aarhus
- Denmark
| | - T. Stevnsner
- Aarhus University
- Department of Molecular Biology and Genetics
- Aarhus
- Denmark
| | - B. R. Knudsen
- Aarhus University
- Department of Molecular Biology and Genetics
- Aarhus
- Denmark
- Aarhus University
| | - Y. P. Ho
- The Chinese University of Hong Kong
- Division of Biomedical Engineering
- Department of Electronic Engineering
- Faculty of Engineering
- Shatin, N.T
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31
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Chang CC, Yuan W, Roan HY, Chang JL, Huang HC, Lee YC, Tsay HJ, Liu HK. The ethyl acetate fraction of corn silk exhibits dual antioxidant and anti-glycation activities and protects insulin-secreting cells from glucotoxicity. Altern Ther Health Med 2016; 16:432. [PMID: 27809830 PMCID: PMC5294807 DOI: 10.1186/s12906-016-1382-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/07/2016] [Indexed: 11/10/2022]
Abstract
Background In this study, we aimed to develop a Stigmata Maydis (corn silk) fraction with dual bio-activities against oxidative stress and protein glycation to protect β-cells from diabetes-induced failure. Methods Corn silk fractions were prepared by partition and chemically characterised by thin-layer chromatography. Free radical scavenging assay, glycation assay, and cell-based viability test (neutral red) were employed to decide the best fraction. Cell death analysis was executed by annexin V/ Propidium iodide staining. Cell proliferation was measured by WST-1. Finally, β-cell function was evaluated by β-cell marker gene expression (RT-PCR) and acute insulin secretion test. Results Four corn silk fractions were prepared from an ethanolic crude extract of corn silk. In vitro assays indicate ethyl acetate fraction (YMS-EA) was the most potent fraction. YMS-EA also attenuated the hydrogen peroxide- or methylglyoxal-induced induction of reactive oxygen species, reduction of cell viability, and inhibition of cell proliferation. However, YMS-EA was unable to prevent hydrogen peroxide-induced apoptosis or advanced glycation end-products-induced toxicity. Under hyperglycemic conditions, YMS-EA effectively reduced ROS levels, improved mRNA expression of insulin, glucokinase, and PDX-1, and enhanced glucose-stimulated insulin secretion. The similarity of bioactivities among apigenin, luteolin, and YMS-EA indicated that dual activities of YMS-EA might be derived from those compounds. Conclusions We concluded that YMS-EA fraction could be developed as a preventive food agent against the glucotoxicity to β-cells in Type 2 diabetes.
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