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Grubelnik V, Zmazek J, Gosak M, Marhl M. The role of anaplerotic metabolism of glucose and glutamine in insulin secretion: A model approach. Biophys Chem 2024; 311:107270. [PMID: 38833963 DOI: 10.1016/j.bpc.2024.107270] [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: 01/31/2024] [Revised: 05/22/2024] [Accepted: 05/22/2024] [Indexed: 06/06/2024]
Abstract
We propose a detailed computational beta cell model that emphasizes the role of anaplerotic metabolism under glucose and glucose-glutamine stimulation. This model goes beyond the traditional focus on mitochondrial oxidative phosphorylation and ATP-sensitive K+ channels, highlighting the predominant generation of ATP from phosphoenolpyruvate in the vicinity of KATP channels. It also underlines the modulatory role of H2O2 as a signaling molecule in the first phase of glucose-stimulated insulin secretion. In the second phase, the model emphasizes the critical role of anaplerotic pathways, activated by glucose stimulation via pyruvate carboxylase and by glutamine via glutamate dehydrogenase. It particularly focuses on the production of NADPH and glutamate as key enhancers of insulin secretion. The predictions of the model are consistent with empirical data, highlighting the complex interplay of metabolic pathways and emphasizing the primary role of glucose and the facilitating role of glutamine in insulin secretion. By delineating these crucial metabolic pathways, the model provides valuable insights into potential therapeutic targets for diabetes.
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Affiliation(s)
- Vladimir Grubelnik
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Koroška cesta 46, 2000 Maribor, Slovenia
| | - Jan Zmazek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia
| | - Marko Gosak
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia; Alma Mater Europaea ECM, Slovenska ulica 17, 2000 Maribor, Slovenia
| | - Marko Marhl
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia; Faculty of Medicine, University of Maribor, Taborska ulica 8, 2000 Maribor, Slovenia; Faculty of Education, University of Maribor, Koroška cesta 160, 2000 Maribor, Slovenia.
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2
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Mahboub P, Aburawi M, Ozgur OS, Pendexter C, Cronin S, Lin FM, Jain R, Karabacak MN, Karimian N, Tessier SN, Markmann JF, Yeh H, Uygun K. Gradual rewarming with a hemoglobin-based oxygen carrier improves viability of donation after circulatory death in rat livers. FRONTIERS IN TRANSPLANTATION 2024; 3:1353124. [PMID: 38993754 PMCID: PMC11235298 DOI: 10.3389/frtra.2024.1353124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 06/10/2024] [Indexed: 07/13/2024]
Abstract
Background Donation after circulatory death (DCD) grafts are vital for increasing available donor organs. Gradual rewarming during machine perfusion has proven effective in mitigating reperfusion injury and enhancing graft quality. Limited data exist on artificial oxygen carriers as an effective solution to meet the increasing metabolic demand with temperature changes. The aim of the present study was to assess the efficacy and safety of utilizing a hemoglobin-based oxygen carrier (HBOC) during the gradual rewarming of DCD rat livers. Methods Liver grafts were procured after 30 min of warm ischemia. The effect of 90 min of oxygenated rewarming perfusion from ice cold temperatures (4 °C) to 37 °C with HBOC after cold storage was evaluated and the results were compared with cold storage alone. Reperfusion at 37 °C was performed to assess the post-preservation recovery. Results Gradual rewarming with HBOC significantly enhanced recovery, demonstrated by markedly lower lactate levels and reduced vascular resistance compared to cold-stored liver grafts. Increased bile production in the HBOC group was noted, indicating improved liver function and bile synthesis capacity. Histological examination showed reduced cellular damage and better tissue preservation in the HBOC-treated livers compared to those subjected to cold storage alone. Conclusion This study suggests the safety of using HBOC during rewarming perfusion of rat livers as no harmful effect was detected. Furthermore, the viability assessment indicated improvement in graft function.
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Affiliation(s)
- Paria Mahboub
- Department of Surgery, University Medical Center Groningen, Groningen, Netherlands
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Mohamed Aburawi
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
- Transplant Center, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - O Sila Ozgur
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Casie Pendexter
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Stephanie Cronin
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Florence Min Lin
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Rohil Jain
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Murat N Karabacak
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Negin Karimian
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - Shannon N Tessier
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
| | - James F Markmann
- Transplant Center, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Heidi Yeh
- Transplant Center, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Korkut Uygun
- Center for Engineering in Medicine and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Department of Research, Shriners Hospitals for Children, Boston, MA, United States
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3
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Chong ACN, Vandana JJ, Jeng G, Li G, Meng Z, Duan X, Zhang T, Qiu Y, Duran-Struuck R, Coker K, Wang W, Li Y, Min Z, Zuo X, de Silva N, Chen Z, Naji A, Hao M, Liu C, Chen S. Checkpoint kinase 2 controls insulin secretion and glucose homeostasis. Nat Chem Biol 2024; 20:566-576. [PMID: 37945898 PMCID: PMC11062908 DOI: 10.1038/s41589-023-01466-4] [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: 11/29/2021] [Accepted: 10/03/2023] [Indexed: 11/12/2023]
Abstract
After the discovery of insulin, a century ago, extensive work has been done to unravel the molecular network regulating insulin secretion. Here we performed a chemical screen and identified AZD7762, a compound that potentiates glucose-stimulated insulin secretion (GSIS) of a human β cell line, healthy and type 2 diabetic (T2D) human islets and primary cynomolgus macaque islets. In vivo studies in diabetic mouse models and cynomolgus macaques demonstrated that AZD7762 enhances GSIS and improves glucose tolerance. Furthermore, genetic manipulation confirmed that ablation of CHEK2 in human β cells results in increased insulin secretion. Consistently, high-fat-diet-fed Chk2-/- mice show elevated insulin secretion and improved glucose clearance. Finally, untargeted metabolic profiling demonstrated the key role of the CHEK2-PP2A-PLK1-G6PD-PPP pathway in insulin secretion. This study successfully identifies a previously unknown insulin secretion regulating pathway that is conserved across rodents, cynomolgus macaques and human β cells in both healthy and T2D conditions.
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Affiliation(s)
- Angie Chi Nok Chong
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
| | - J Jeya Vandana
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York City, NY, USA
| | - Ginnie Jeng
- Department of Urology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ge Li
- Department of Medicine, Weill Cornell Medicine, New York City, NY, USA
- Department of Biological Sciences, Bronx Community College, City University of New York, Bronx, NY, USA
| | - Zihe Meng
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
| | - Xiaohua Duan
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA
| | - Tuo Zhang
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York City, NY, USA
| | - Yunping Qiu
- Department of Medicine, Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Raimon Duran-Struuck
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Kimberly Coker
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Wei Wang
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Yanjing Li
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Zaw Min
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Xi Zuo
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Neranjan de Silva
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA
| | - Zhengming Chen
- Department of Population Health Sciences, Weill Cornell Medicine, New York City, NY, USA
| | - Ali Naji
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Mingming Hao
- Department of Biochemistry, Weill Cornell Medicine, New York City, NY, USA
| | - Chengyang Liu
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
| | - Shuibing Chen
- Department of Surgery, Weill Cornell Medicine, New York City, NY, USA.
- Center for Genomic Health, Weill Cornell Medicine, New York City, NY, USA.
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4
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Zhao L, Zheng J, Qin J, Xu X, Liu X, Yang S, Li S, Chen B, Du J, Dong R. Combined Astragalus, vitamin C, and vitamin E alleviate DEHP-induced oxidative stress and the decreased of insulin synthesis and secretion in INS-1 cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 268:115675. [PMID: 37984288 DOI: 10.1016/j.ecoenv.2023.115675] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/30/2023] [Accepted: 11/09/2023] [Indexed: 11/22/2023]
Abstract
Di-(2-ethylhexyl)-phthalate (DEHP), a common Phthalic acid ester (PAEs), has been reported to be associated with diabetes mellitus, yet the underlying mechanisms remain unknown. Combined nutrient interventions have been shown to alleviate the diabetic toxicity of DEHP. However, the effects and mechanisms of the combined intervention of Astragalus and vitamins (C and E) are currently unknown. In this study, we investigated the potential mechanisms of DEHP-induced diabetes mellitus through transcriptome analysis and vitro experiments using rat insulinoma cells (INS-1 cells). Furthermore, we explored the protection of the combined Astragalus, vitamin C, and vitamin E on DEHP-induced diabetes mellitus through these mechanisms. INS-1 cells in the logarithmic growth period were exposed to 125 umol/L DEHP followed by high-throughput sequencing analysis. The cell proliferation inhibition rate was determined using MTT assay for each group, and the cell apoptosis rate and intracellular ROS level were measured using flow cytometer. Finally, insulin levels and markers of oxidative stress were detected using ELISA kits in different groups. A total of 372 differentially expressed genes were found between the 125 umol/L DEHP and control groups, subsequent functional enrichment analyses indicated that DEHP induced oxidative stress and disturbed insulin levels. In INS-1 cells, the rate of cell proliferation inhibition, apoptosis, and the degree of oxidative stress increased concentration-dependently with increasing DEHP concentrations, while antioxidant intervention could reverse these changes. Insulin synthesis and secretion decreased after 240 μmol/L DEHP exposure stimulated by 25 mM glucose in INS-1 cells, also could antioxidant intervention alleviate these reductions. Based on these results, the underlying mechanism of DEHP impairing the function of INS-1 cells might be through apoptosis pathways induced by oxidative stress and direct reduction of insulin levels (both synthesis and secretion), while the optimal combination of Astragalus and vitamins (C and E) could exert an alleviating effect.
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Affiliation(s)
- Long Zhao
- Key Lab of Public Health Safety of the Ministry of Education, Institute of Nutrition, School of Public Health, Fudan University, Shanghai 200032, China
| | | | - Jin Qin
- Affiliated cancer hospital of Zhengzhou University, Henan Cancer Hospital, ZhengZhou 450003, China
| | - Xin Xu
- Key Lab of Public Health Safety of the Ministry of Education, Institute of Nutrition, School of Public Health, Fudan University, Shanghai 200032, China
| | - Xinyuan Liu
- Key Lab of Public Health Safety of the Ministry of Education, Institute of Nutrition, School of Public Health, Fudan University, Shanghai 200032, China
| | - Shuyu Yang
- Nutrilite Health Institute, Shanghai 200023, China
| | - Shuguang Li
- Key Lab of Public Health Safety of the Ministry of Education, Institute of Nutrition, School of Public Health, Fudan University, Shanghai 200032, China
| | - Bo Chen
- Key Lab of Public Health Safety of the Ministry of Education, Institute of Nutrition, School of Public Health, Fudan University, Shanghai 200032, China
| | - Jun Du
- Nutrilite Health Institute, Shanghai 200023, China.
| | - Ruihua Dong
- Key Lab of Public Health Safety of the Ministry of Education, Institute of Nutrition, School of Public Health, Fudan University, Shanghai 200032, China.
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Marques C, Friedrich F, Liu L, Castoldi F, Pietrocola F, Lanekoff I. Global and Spatial Metabolomics of Individual Cells Using a Tapered Pneumatically Assisted nano-DESI Probe. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2518-2524. [PMID: 37830184 PMCID: PMC10623638 DOI: 10.1021/jasms.3c00239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/14/2023]
Abstract
Single-cell metabolomics has the potential to reveal unique insights into intracellular mechanisms and biological processes. However, the detection of metabolites from individual cells is challenging due to their versatile chemical properties and concentrations. Here, we demonstrate a tapered probe for pneumatically assisted nanospray desorption electrospray ionization (PA nano-DESI) mass spectrometry that enables both chemical imaging of larger cells and global metabolomics of smaller 15 μm cells. Additionally, by depositing cells in predefined arrays, we show successful metabolomics from three individual INS-1 cells per minute, which enabled the acquisition of data from 479 individual cells. Several cells were used to optimize analytical conditions, and 93 or 97 cells were used to monitor metabolome alterations in INS-1 cells after exposure to a low or high glucose concentration, respectively. Our analytical approach offers insights into cellular heterogeneity and provides valuable information about cellular processes and responses in individual cells.
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Affiliation(s)
- Cátia Marques
- Department
of Chemistry—BMC, Uppsala University, 75123 Uppsala, Sweden
| | - Felix Friedrich
- Department
of Chemistry—BMC, Uppsala University, 75123 Uppsala, Sweden
| | - Liangwen Liu
- Department
of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden
| | - Francesca Castoldi
- Department
of Biosciences and Nutrition, Karolinska
Institute, 14152 Huddinge, Sweden
| | - Federico Pietrocola
- Department
of Biosciences and Nutrition, Karolinska
Institute, 14152 Huddinge, Sweden
| | - Ingela Lanekoff
- Department
of Chemistry—BMC, Uppsala University, 75123 Uppsala, Sweden
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Barsby T, Vähäkangas E, Ustinov J, Montaser H, Ibrahim H, Lithovius V, Kuuluvainen E, Chandra V, Saarimäki-Vire J, Katajisto P, Hietakangas V, Otonkoski T. Aberrant metabolite trafficking and fuel sensitivity in human pluripotent stem cell-derived islets. Cell Rep 2023; 42:112970. [PMID: 37556323 DOI: 10.1016/j.celrep.2023.112970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/09/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023] Open
Abstract
Pancreatic islets regulate blood glucose homeostasis through the controlled release of insulin; however, current metabolic models of glucose-sensitive insulin secretion are incomplete. A comprehensive understanding of islet metabolism is integral to studies of endocrine cell development as well as diabetic islet dysfunction. Human pluripotent stem cell-derived islets (SC-islets) are a developmentally relevant model of human islet function that have great potential in providing a cure for type 1 diabetes. Using multiple 13C-labeled metabolic fuels, we demonstrate that SC-islets show numerous divergent patterns of metabolite trafficking in proposed insulin release pathways compared with primary human islets but are still reliant on mitochondrial aerobic metabolism to derive function. Furthermore, reductive tricarboxylic acid cycle activity and glycolytic metabolite cycling occur in SC-islets, suggesting that non-canonical coupling factors are also present. In aggregate, we show that many facets of SC-islet metabolism overlap with those of primary islets, albeit with a retained immature signature.
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Affiliation(s)
- Tom Barsby
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Eliisa Vähäkangas
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jarkko Ustinov
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Hossam Montaser
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Hazem Ibrahim
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Väinö Lithovius
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Emilia Kuuluvainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Vikash Chandra
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jonna Saarimäki-Vire
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pekka Katajisto
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Children's Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
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7
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Holendova B, Plecita-Hlavata L. Cysteine residues in signal transduction and its relevance in pancreatic beta cells. Front Endocrinol (Lausanne) 2023; 14:1221520. [PMID: 37455926 PMCID: PMC10339824 DOI: 10.3389/fendo.2023.1221520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/13/2023] [Indexed: 07/18/2023] Open
Abstract
Cysteine is one of the least abundant but most conserved amino acid residues in proteins, playing a role in their structure, metal binding, catalysis, and redox chemistry. Thiols present in cysteines can be modified by post-translational modifications like sulfenylation, acylation, or glutathionylation, regulating protein activity and function and serving as signals. Their modification depends on their position in the structure, surrounding amino acids, solvent accessibility, pH, etc. The most studied modifications are the redox modifications by reactive oxygen, nitrogen, and sulfur species, leading to reversible changes that serve as cell signals or irreversible changes indicating oxidative stress and cell damage. Selected antioxidants undergoing reversible oxidative modifications like peroxiredoxin-thioredoxin system are involved in a redox-relay signaling that can propagate to target proteins. Cysteine thiols can also be modified by acyl moieties' addition (derived from lipid metabolism), resulting in protein functional modification or changes in protein anchoring in the membrane. In this review, we update the current knowledge on cysteine modifications and their consequences in pancreatic β-cells. Because β-cells exhibit well-balanced redox homeostasis, the redox modifications of cysteines here serve primarily for signaling purposes. Similarly, lipid metabolism provides regulatory intermediates that have been shown to be necessary in addition to redox modifications for proper β-cell function and, in particular, for efficient insulin secretion. On the contrary, the excess of reactive oxygen, nitrogen, and sulfur species and the imbalance of lipids under pathological conditions cause irreversible changes and contribute to oxidative stress leading to cell failure and the development of type 2 diabetes.
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Affiliation(s)
| | - Lydie Plecita-Hlavata
- Laboratory of Pancreatic Islet Research, Institute of Physiology, Czech Academy of Sciences, Prague, Czechia
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8
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Wu D, Jiang Y, Wang Z, Ni Y, Ma A, Zhou Y, Liu R, Lou YR, Wang Q. Metabolomics analysis of islet regeneration in partial pancreatectomy mice reveals increased levels of long-chain fatty acids and activated cAMP signaling pathway. Biochem Biophys Res Commun 2023; 667:34-42. [PMID: 37207562 DOI: 10.1016/j.bbrc.2023.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 05/03/2023] [Indexed: 05/21/2023]
Abstract
Islet regeneration is a complex process involving multiple metabolic adaptions, but the specific characterization of the islet metabolome in relation to cell proliferation has not been established. This study aimed to investigate the metabolomic changes of regenerative islets from partial pancreatectomy (Ppx) mice and speculate underlying mechanisms. Islet samples were collected from C57/BL6 mice undergoing 70-80% Ppx or sham surgery, followed by analyses of glucose homeostasis, islet morphology, and untargeted metabolomics profiles using liquid chromatography-tandem mass spectrometry (LC-MS/MS). There is no difference in blood glucose and body weight between sham and Ppx mice. After surgery, the Ppx mice showed impaired glucose tolerance, increased Ki67 positive beta cells, and elevated beta-cell mass. LC-MS/MS analysis identified fourteen differentially changed metabolites in islets of Ppx mice, including long-chain fatty acids (e.g., docosahexaenoic acid) and amino acid derivatives (e.g., creatine). Pathway analysis based on the KEGG database revealed five significantly enriched signaling pathways including cAMP signaling pathway. Further immunostaining assay on pancreatic tissue sections showed the levels of p-CREB, a transcription factor downstream of cAMP, elevated in islets from Ppx mice. In conclusion, our results demonstrate that islet regeneration involves metabolic alterations in long-chain fatty acids and amino acid derivatives, as well as the activation of the cAMP signaling pathway.
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Affiliation(s)
- Di Wu
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China
| | - Yaojing Jiang
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China
| | - Zhihong Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China
| | - Yunzhi Ni
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China
| | - Anran Ma
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China
| | - Yue Zhou
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China
| | - Rui Liu
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China
| | - Yan-Ru Lou
- School of Pharmacy, Fudan University, Shanghai, China
| | - Qinghua Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China; Institute of Endocrinology and Diabetes, Fudan University, Shanghai, China.
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9
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Panten U, Brüning D, Rustenbeck I. Regulation of insulin secretion in mouse islets: metabolic amplification by alpha-ketoisocaproate coincides with rapid and sustained increase in acetyl-CoA content. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2023; 396:353-364. [PMID: 36355207 PMCID: PMC9832085 DOI: 10.1007/s00210-022-02290-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 09/05/2022] [Indexed: 11/12/2022]
Abstract
Glucose and alpha-ketoisocaproate, the keto acid analogue of leucine, stimulate insulin secretion in the absence of other exogenous fuels. Their mitochondrial metabolism in the beta-cell raises the cytosolic ATP/ADP ratio, thereby providing the triggering signal for the exocytosis of the insulin granules. However, additional amplifying signals are required for the full extent of insulin secretion stimulated by these fuels. While it is generally recognized that the amplifying signals are also derived from the mitochondrial metabolism, their exact nature is still unclear. The current study tests the hypothesis that the supply of cytosolic acetyl-CoA is a signal in the amplifying pathway. The contents of acetyl-CoA and acetyl-CoA plus CoA-SH were measured in isolated mouse islets. Insulin secretion was recorded in isolated perifused islets. In islets, the ATP-sensitive K+ channels of which were pharmacologically closed and which were preincubated without exogenous fuel, 10 mmol/L alpha-ketoisocaproate enhanced the acetyl-CoA content after 5 and 20 min incubations and decreased the acetyl-CoA plus CoA-SH within 5 min, but not after 20 min. In islets not exposed to drugs, the preincubation with 3 mmol/L glucose, a non-triggering concentration, elevated the acetyl-CoA content. This content was further increased after 5 min and 20 min incubations with 30 mmol/L glucose, concurrent with a strong increase in insulin secretion. Alpha-ketoisocaproate and glucose increase the supply of acetyl-CoA in the beta-cell cytosol during both phases of insulin secretion. Most likely, this increase provides a signal for the metabolic amplification.
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Affiliation(s)
- Uwe Panten
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106 Braunschweig, Germany
| | - Dennis Brüning
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106 Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106 Braunschweig, Germany
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10
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Yang R, Zheng J, Qin J, Liu S, Liu X, Gu Y, Yang S, Du J, Li S, Chen B, Dong R. Dibutyl phthalate affects insulin synthesis and secretion by regulating the mitochondrial apoptotic pathway and oxidative stress in rat insulinoma cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 249:114396. [PMID: 36508788 DOI: 10.1016/j.ecoenv.2022.114396] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Dibutyl phthalate (DBP) is a typical phthalate (PAEs). The environmental health risks of DBP have gradually attracted attention due to the common use in the production of plastics, cosmetics and skin care products. DBP was associated with diabetes, but its mechanism is not clear. In this study, an in vitro culture system of rat insulinoma (INS-1) cells was established to explore the effect of DBP on insulin synthesis and secretion and the potential mechanisms. INS-1 cells were cultured in RPMI-1640 medium containing 10% fetal bovine serum and treated with 15, 30, 60 and 120 μmol/L of DBP and dimethyl sulfoxide (vehicle, < 0.1%) for 24 h. The contents of insulin in the intracellular fluid and the extracellular fluid of the cells were measured. The results showed that insulin synthesis and secretion in INS-1 cells were significantly decreased in 120 μmol/L DBP group. The apoptosis rate and mitochondrial membrane potential of INS-1 cells were measured by flow cytometry with annexin V-FITC conjugate and PI, and JC-1, respectively. The results showed that DBP caused an increase in the apoptosis rate and a significant decrease in the mitochondrial membrane potential in INS-1 cells in 60 μmol/L and 120 μmol/L DBP group. The results of western blot showed that the expression of Bax/Bcl-2, caspase-3, caspase-9 and Cyt-C were significantly increased. Meanwhile, the level of oxidative stress in INS-1 cells was detected by fluorescent probes DCFH-DA and western blot. With the increase of DBP exposure, the oxidative stress levels (MDA, GSH/GSSG) were increased; and the antioxidant index (SOD) levels were decreased. Our experimental results provide reliable evidence that DBP induced apoptosis and functional impairment in INS-1 cells through the mitochondrial apoptotic pathway and oxidative stress. Therefore, we hypothesized that interference with these two pathways could be considered in the development of preventive protection measures.
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Affiliation(s)
- Ruoru Yang
- School of Public Health, Institute of Nutrition, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai 200032, China.
| | | | - Jin Qin
- Affiliated cancer hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou 450003, China.
| | - Shaojie Liu
- School of Public Health, Institute of Nutrition, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai 200032, China.
| | - Xinyuan Liu
- School of Public Health, Institute of Nutrition, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai 200032, China.
| | - Yiying Gu
- School of Public Health, Institute of Nutrition, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai 200032, China.
| | - Shuyu Yang
- Nutrilite Health Institute, Shanghai 200023, China.
| | - Jun Du
- Nutrilite Health Institute, Shanghai 200023, China.
| | - Shuguang Li
- School of Public Health, Institute of Nutrition, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai 200032, China.
| | - Bo Chen
- School of Public Health, Institute of Nutrition, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai 200032, China.
| | - Ruihua Dong
- School of Public Health, Institute of Nutrition, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai 200032, China.
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11
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Tong Y, Sun M, Chen L, Wang Y, Li Y, Li L, Zhang X, Cai Y, Qie J, Pang Y, Xu Z, Zhao J, Zhang X, Liu Y, Tian S, Qin Z, Feng J, Zhang F, Zhu J, Xu Y, Lou W, Ji Y, Zhao J, He F, Hou Y, Ding C. Proteogenomic insights into the biology and treatment of pancreatic ductal adenocarcinoma. J Hematol Oncol 2022; 15:168. [PMID: 36434634 PMCID: PMC9701038 DOI: 10.1186/s13045-022-01384-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/02/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with poor prognosis. Proteogenomic characterization and integrative proteomic analysis provide a functional context to annotate genomic abnormalities with prognostic value. METHODS We performed an integrated multi-omics analysis, including whole-exome sequencing, RNA-seq, proteomic, and phosphoproteomic analysis of 217 PDAC tumors with paired non-tumor adjacent tissues. In vivo functional experiments were performed to further illustrate the biological events related to PDAC tumorigenesis and progression. RESULTS A comprehensive proteogenomic landscape revealed that TP53 mutations upregulated the CDK4-mediated cell proliferation process and led to poor prognosis in younger patients. Integrative multi-omics analysis illustrated the proteomic and phosphoproteomic alteration led by genomic alterations such as KRAS mutations and ADAM9 amplification of PDAC tumorigenesis. Proteogenomic analysis combined with in vivo experiments revealed that the higher amplification frequency of ADAM9 (8p11.22) could drive PDAC metastasis, though downregulating adhesion junction and upregulating WNT signaling pathway. Proteome-based stratification of PDAC revealed three subtypes (S-I, S-II, and S-III) related to different clinical and molecular features. Immune clustering defined a metabolic tumor subset that harbored FH amplicons led to better prognosis. Functional experiments revealed the role of FH in altering tumor glycolysis and in impacting PDAC tumor microenvironments. Experiments utilizing both in vivo and in vitro assay proved that loss of HOGA1 promoted the tumor growth via activating LARP7-CDK1 pathway. CONCLUSIONS This proteogenomic dataset provided a valuable resource for researchers and clinicians seeking for better understanding and treatment of PDAC.
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Affiliation(s)
- Yexin Tong
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Mingjun Sun
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Lingli Chen
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Yunzhi Wang
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Yan Li
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Lingling Li
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Xuan Zhang
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Yumeng Cai
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Jingbo Qie
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Yanrui Pang
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Ziyan Xu
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Jiangyan Zhao
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Xiaolei Zhang
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Yang Liu
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Sha Tian
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Zhaoyu Qin
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Jinwen Feng
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Fan Zhang
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Jiajun Zhu
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Yifan Xu
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Wenhui Lou
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Yuan Ji
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Jianyuan Zhao
- grid.16821.3c0000 0004 0368 8293Institute for Development and Regenerative Cardiovascular Medicine, MOE-Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092 China ,grid.207374.50000 0001 2189 3846Department of Anatomy and Neuroscience Research Institute, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, 450001 China
| | - Fuchu He
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China ,grid.419611.a0000 0004 0457 9072State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing, 102206 China ,grid.506261.60000 0001 0706 7839Research Unit of Proteomics Driven Cancer Precision Medicine, Chinese Academy of Medical Sciences, Beijing, 102206 China
| | - Yingyong Hou
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
| | - Chen Ding
- grid.8547.e0000 0001 0125 2443Institute of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Human Phenome Institute, Department of Pathology, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200433 China
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12
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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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13
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Monitoring glycolytic dynamics in single cells using a fluorescent biosensor for fructose 1,6-bisphosphate. Proc Natl Acad Sci U S A 2022; 119:e2204407119. [PMID: 35881794 PMCID: PMC9351453 DOI: 10.1073/pnas.2204407119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cellular metabolism is regulated over space and time to ensure that energy production is efficiently matched with consumption. Fluorescent biosensors are useful tools for studying metabolism as they enable real-time detection of metabolite abundance with single-cell resolution. For monitoring glycolysis, the intermediate fructose 1,6-bisphosphate (FBP) is a particularly informative signal as its concentration is strongly correlated with flux through the whole pathway. Using GFP insertion into the ligand-binding domain of the Bacillus subtilis transcriptional regulator CggR, we developed a fluorescent biosensor for FBP termed HYlight. We demonstrate that HYlight can reliably report the real-time dynamics of glycolysis in living cells and tissues, driven by various metabolic or pharmacological perturbations, alone or in combination with other physiologically relevant signals. Using this sensor, we uncovered previously unknown aspects of β-cell glycolytic heterogeneity and dynamics.
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14
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Abstract
The ability to maintain normoglycaemia, through glucose-sensitive insulin release, is a key aspect of postnatal beta cell function. However, terminally differentiated beta cell identity does not necessarily imply functional maturity. Beta cell maturation is therefore a continuation of beta cell development, albeit a process that occurs postnatally in mammals. Although many important features have been identified in the study of beta cell maturation, as of yet no unified mechanistic model of beta cell functional maturity exists. Here, we review recent findings about the underlying mechanisms of beta cell functional maturation. These findings include systemic hormonal and nutritional triggers that operate through energy-sensing machinery shifts within beta cells, resulting in primed metabolic states that allow for appropriate glucose trafficking and, ultimately, insulin release. We also draw attention to the expansive synergistic nature of these pathways and emphasise that beta cell maturation is dependent on overlapping regulatory and metabolic networks.
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Affiliation(s)
- Tom Barsby
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Children's Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
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15
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Ježek P, Holendová B, Jabůrek M, Dlasková A, Plecitá-Hlavatá L. Contribution of Mitochondria to Insulin Secretion by Various Secretagogues. Antioxid Redox Signal 2022; 36:920-952. [PMID: 34180254 PMCID: PMC9125579 DOI: 10.1089/ars.2021.0113] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Significance: Mitochondria determine glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells by elevating ATP synthesis. As the metabolic and redox hub, mitochondria provide numerous links to the plasma membrane channels, insulin granule vesicles (IGVs), cell redox, NADH, NADPH, and Ca2+ homeostasis, all affecting insulin secretion. Recent Advances: Mitochondrial redox signaling was implicated in several modes of insulin secretion (branched-chain ketoacid [BCKA]-, fatty acid [FA]-stimulated). Mitochondrial Ca2+ influx was found to enhance GSIS, reflecting cytosolic Ca2+ oscillations induced by action potential spikes (intermittent opening of voltage-dependent Ca2+ and K+ channels) or the superimposed Ca2+ release from the endoplasmic reticulum (ER). The ATPase inhibitory factor 1 (IF1) was reported to tune the glucose sensitivity range for GSIS. Mitochondrial protein kinase A was implicated in preventing the IF1-mediated inhibition of the ATP synthase. Critical Issues: It is unknown how the redox signal spreads up to the plasma membrane and what its targets are, what the differences in metabolic, redox, NADH/NADPH, and Ca2+ signaling, and homeostasis are between the first and second GSIS phase, and whether mitochondria can replace ER in the amplification of IGV exocytosis. Future Directions: Metabolomics studies performed to distinguish between the mitochondrial matrix and cytosolic metabolites will elucidate further details. Identifying the targets of cell signaling into mitochondria and of mitochondrial retrograde metabolic and redox signals to the cell will uncover further molecular mechanisms for insulin secretion stimulated by glucose, BCKAs, and FAs, and the amplification of secretion by glucagon-like peptide (GLP-1) and metabotropic receptors. They will identify the distinction between the hub β-cells and their followers in intact and diabetic states. Antioxid. Redox Signal. 36, 920-952.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Andrea Dlasková
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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16
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Essaouiba A, Jellali R, Poulain S, Tokito F, Gilard F, Gakière B, Kim SH, Legallais C, Sakai Y, Leclerc E. Analysis of the transcriptome and metabolome of pancreatic spheroids derived from human induced pluripotent stem cells and matured in an organ-on-a-chip. Mol Omics 2022; 18:791-804. [DOI: 10.1039/d2mo00132b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The differentiation of pancreatic cells from hiPSC is one of the emerging strategies to achieve an in vitro pancreas model. Here, hiPSC-derived β-like-cells spheroids were cultured in microfluidic environment and characterized using omics analysis.
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Affiliation(s)
- Amal Essaouiba
- Université de technologie de Compiègne, CNRS, Biomechanics and Bioengineering, Centre de recherche Royallieu CS 60319, 60203 Compiegne, France
- CNRS IRL 2820, Laboratory for Integrated Micro Mechatronic Systems, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba; Meguro-ku, Tokyo, 153-8505, Japan
- Department of Chemical System Engineering, Graduate School of Engineering, the University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Rachid Jellali
- Université de technologie de Compiègne, CNRS, Biomechanics and Bioengineering, Centre de recherche Royallieu CS 60319, 60203 Compiegne, France
| | - Stéphane Poulain
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba; Meguro-ku, Tokyo, 153-8505, Japan
| | - Fumiya Tokito
- Department of Chemical System Engineering, Graduate School of Engineering, the University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Françoise Gilard
- Plateforme Métabolisme-Métabolome, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université d’Evry, Université de Paris, 91190 Gif-sur-Yvette, France
| | - Bertrand Gakière
- Plateforme Métabolisme-Métabolome, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université d’Evry, Université de Paris, 91190 Gif-sur-Yvette, France
| | - Soo Hyeon Kim
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba; Meguro-ku, Tokyo, 153-8505, Japan
| | - Cécile Legallais
- Université de technologie de Compiègne, CNRS, Biomechanics and Bioengineering, Centre de recherche Royallieu CS 60319, 60203 Compiegne, France
| | - Yasuyuki Sakai
- CNRS IRL 2820, Laboratory for Integrated Micro Mechatronic Systems, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba; Meguro-ku, Tokyo, 153-8505, Japan
- Department of Chemical System Engineering, Graduate School of Engineering, the University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Eric Leclerc
- Université de technologie de Compiègne, CNRS, Biomechanics and Bioengineering, Centre de recherche Royallieu CS 60319, 60203 Compiegne, France
- CNRS IRL 2820, Laboratory for Integrated Micro Mechatronic Systems, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba; Meguro-ku, Tokyo, 153-8505, Japan
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17
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Hoang M, Jentz E, Janssen SM, Nasteska D, Cuozzo F, Hodson DJ, Tupling AR, Fong GH, Joseph JW. Isoform-specific Roles of Prolyl Hydroxylases in the Regulation of Pancreatic β-Cell Function. Endocrinology 2022; 163:6413706. [PMID: 34718519 PMCID: PMC8643417 DOI: 10.1210/endocr/bqab226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Indexed: 11/19/2022]
Abstract
Pancreatic β-cells can secrete insulin via 2 pathways characterized as KATP channel -dependent and -independent. The KATP channel-independent pathway is characterized by a rise in several potential metabolic signaling molecules, including the NADPH/NADP+ ratio and α-ketoglutarate (αKG). Prolyl hydroxylases (PHDs), which belong to the αKG-dependent dioxygenase superfamily, are known to regulate the stability of hypoxia-inducible factor α. In the current study, we assess the role of PHDs in vivo using the pharmacological inhibitor dimethyloxalylglycine (DMOG) and generated β-cell-specific knockout (KO) mice for all 3 isoforms of PHD (β-PHD1 KO, β-PHD2 KO, and β-PHD3 KO mice). DMOG inhibited in vivo insulin secretion in response to glucose challenge and inhibited the first phase of insulin secretion but enhanced the second phase of insulin secretion in isolated islets. None of the β-PHD KO mice showed any significant in vivo defects associated with glucose tolerance and insulin resistance except for β-PHD2 KO mice which had significantly increased plasma insulin during a glucose challenge. Islets from both β-PHD1 KO and β-PHD3 KO had elevated β-cell apoptosis and reduced β-cell mass. Isolated islets from β-PHD1 KO and β-PHD3 KO had impaired glucose-stimulated insulin secretion and glucose-stimulated increases in the ATP/ADP and NADPH/NADP+ ratio. All 3 PHD isoforms are expressed in β-cells, with PHD3 showing the most distinct expression pattern. The lack of each PHD protein did not significantly impair in vivo glucose homeostasis. However, β-PHD1 KO and β-PHD3 KO mice had defective β-cell mass and islet insulin secretion, suggesting that these mice may be predisposed to developing diabetes.
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Affiliation(s)
- Monica Hoang
- School of Pharmacy, University of Waterloo, Kitchener, ON, Canada
| | - Emelien Jentz
- School of Pharmacy, University of Waterloo, Kitchener, ON, Canada
| | - Sarah M Janssen
- School of Pharmacy, University of Waterloo, Kitchener, ON, Canada
| | - Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Federica Cuozzo
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - A Russell Tupling
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Guo-Hua Fong
- Center for Vascular Biology, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Jamie W Joseph
- School of Pharmacy, University of Waterloo, Kitchener, ON, Canada
- Correspondence: Jamie W. Joseph, PhD, Health Science Campus Building A, Room 4008, University of Waterloo, 10A Victoria Street South, Kitchener, ON, Canada, N2G 1C5.
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18
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Ježek P, Holendová B, Jabůrek M, Tauber J, Dlasková A, Plecitá-Hlavatá L. The Pancreatic β-Cell: The Perfect Redox System. Antioxidants (Basel) 2021; 10:antiox10020197. [PMID: 33572903 PMCID: PMC7912581 DOI: 10.3390/antiox10020197] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Pancreatic β-cell insulin secretion, which responds to various secretagogues and hormonal regulations, is reviewed here, emphasizing the fundamental redox signaling by NADPH oxidase 4- (NOX4-) mediated H2O2 production for glucose-stimulated insulin secretion (GSIS). There is a logical summation that integrates both metabolic plus redox homeostasis because the ATP-sensitive K+ channel (KATP) can only be closed when both ATP and H2O2 are elevated. Otherwise ATP would block KATP, while H2O2 would activate any of the redox-sensitive nonspecific calcium channels (NSCCs), such as TRPM2. Notably, a 100%-closed KATP ensemble is insufficient to reach the -50 mV threshold plasma membrane depolarization required for the activation of voltage-dependent Ca2+ channels. Open synergic NSCCs or Cl- channels have to act simultaneously to reach this threshold. The resulting intermittent cytosolic Ca2+-increases lead to the pulsatile exocytosis of insulin granule vesicles (IGVs). The incretin (e.g., GLP-1) amplification of GSIS stems from receptor signaling leading to activating the phosphorylation of TRPM channels and effects on other channels to intensify integral Ca2+-influx (fortified by endoplasmic reticulum Ca2+). ATP plus H2O2 are also required for branched-chain ketoacids (BCKAs); and partly for fatty acids (FAs) to secrete insulin, while BCKA or FA β-oxidation provide redox signaling from mitochondria, which proceeds by H2O2 diffusion or hypothetical SH relay via peroxiredoxin "redox kiss" to target proteins.
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19
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Campbell JE, Newgard CB. Mechanisms controlling pancreatic islet cell function in insulin secretion. Nat Rev Mol Cell Biol 2021; 22:142-158. [PMID: 33398164 DOI: 10.1038/s41580-020-00317-7] [Citation(s) in RCA: 255] [Impact Index Per Article: 85.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 02/07/2023]
Abstract
Metabolic homeostasis in mammals is tightly regulated by the complementary actions of insulin and glucagon. The secretion of these hormones from pancreatic β-cells and α-cells, respectively, is controlled by metabolic, endocrine, and paracrine regulatory mechanisms and is essential for the control of blood levels of glucose. The deregulation of these mechanisms leads to various pathologies, most notably type 2 diabetes, which is driven by the combined lesions of impaired insulin action and a loss of the normal insulin secretion response to glucose. Glucose stimulates insulin secretion from β-cells in a bi-modal fashion, and new insights about the underlying mechanisms, particularly relating to the second or amplifying phase of this secretory response, have been recently gained. Other recent work highlights the importance of α-cell-produced proglucagon-derived peptides, incretin hormones from the gastrointestinal tract and other dietary components, including certain amino acids and fatty acids, in priming and potentiation of the β-cell glucose response. These advances provide a new perspective for the understanding of the β-cell failure that triggers type 2 diabetes.
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Affiliation(s)
- Jonathan E Campbell
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA.,Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC, USA.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA. .,Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC, USA. .,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA.
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20
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White KL, Singla J, Loconte V, Chen JH, Ekman A, Sun L, Zhang X, Francis JP, Li A, Lin W, Tseng K, McDermott G, Alber F, Sali A, Larabell C, Stevens RC. Visualizing subcellular rearrangements in intact β cells using soft x-ray tomography. SCIENCE ADVANCES 2020; 6:eabc8262. [PMID: 33298443 PMCID: PMC7725475 DOI: 10.1126/sciadv.abc8262] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/21/2020] [Indexed: 05/21/2023]
Abstract
Characterizing relationships between cell structures and functions requires mesoscale mapping of intact cells showing subcellular rearrangements following stimulation; however, current approaches are limited in this regard. Here, we report a unique application of soft x-ray tomography to generate three-dimensional reconstructions of whole pancreatic β cells at different time points following glucose-stimulated insulin secretion. Reconstructions following stimulation showed distinct insulin vesicle distribution patterns reflective of altered vesicle pool sizes as they travel through the secretory pathway. Our results show that glucose stimulation caused rapid changes in biochemical composition and/or density of insulin packing, increased mitochondrial volume, and closer proximity of insulin vesicles to mitochondria. Costimulation with exendin-4 (a glucagon-like peptide-1 receptor agonist) prolonged these effects and increased insulin packaging efficiency and vesicle maturation. This study provides unique perspectives on the coordinated structural reorganization and interactions of organelles that dictate cell responses.
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Affiliation(s)
- Kate L White
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA.
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jitin Singla
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Valentina Loconte
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jian-Hua Chen
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Axel Ekman
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Liping Sun
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xianjun Zhang
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - John Paul Francis
- Department of Computer Science, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - Angdi Li
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wen Lin
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - Kaylee Tseng
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - Gerry McDermott
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Frank Alber
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Andrej Sali
- California Institute for Quantitative Biosciences, Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Carolyn Larabell
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Raymond C Stevens
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA.
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
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21
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Boehmer BH, Baker PR, Brown LD, Wesolowski SR, Rozance PJ. Leucine acutely potentiates glucose-stimulated insulin secretion in fetal sheep. J Endocrinol 2020; 247:115-126. [PMID: 32756000 PMCID: PMC7484215 DOI: 10.1530/joe-20-0243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/04/2020] [Indexed: 12/28/2022]
Abstract
A 9-day infusion of leucine into fetal sheep potentiates fetal glucose-stimulated insulin secretion (GSIS). However, there were accompanying pancreatic structural changes that included a larger proportion of β-cells and increased vascularity. Whether leucine can acutely potentiate fetal GSIS in vivo before these structural changes develop is unknown. The mechanisms by which leucine acutely potentiates GSIS in adult islets and insulin-secreting cell lines are well known. These mechanisms involve leucine metabolism, including leucine oxidation. However, it is not clear if leucine-stimulated metabolic pathways are active in fetal islets. We hypothesized that leucine would acutely potentiate GSIS in fetal sheep and that isolated fetal islets are capable of oxidizing leucine. We also hypothesized that leucine would stimulate other metabolic pathways associated with insulin secretion. In pregnant sheep we tested in vivo GSIS with and without an acute leucine infusion. In isolated fetal sheep islets, we measured leucine oxidation with a [1-14C] l-leucine tracer. We also measured concentrations of other amino acids, glucose, and analytes associated with cellular metabolism following incubation of fetal islets with leucine. In vivo, a leucine infusion resulted in glucose-stimulated insulin concentrations that were over 50% higher than controls (P < 0.05). Isolated fetal islets oxidized leucine. Leucine supplementation of isolated fetal islets also resulted in significant activation of metabolic pathways involving leucine and other amino acids. In summary, acute leucine supplementation potentiates fetal GSIS in vivo, likely through pathways related to the oxidation of leucine and catabolism of other amino acids.
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Affiliation(s)
- Brit H. Boehmer
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Peter R. Baker
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Laura D. Brown
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Stephanie R. Wesolowski
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
| | - Paul J. Rozance
- Department of Pediatrics, University of Colorado School of Medicine, Perinatal Research Center, Aurora, Colorado, USA
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22
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Lopez R, Marzban B, Gao X, Lauinger E, Van den Bergh F, Whitesall SE, Converso-Baran K, Burant CF, Michele DE, Beard DA. Impaired Myocardial Energetics Causes Mechanical Dysfunction in Decompensated Failing Hearts. FUNCTION 2020; 1:zqaa018. [PMID: 33074265 PMCID: PMC7552914 DOI: 10.1093/function/zqaa018] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/11/2020] [Accepted: 09/21/2020] [Indexed: 01/06/2023] Open
Abstract
Cardiac mechanical function is supported by ATP hydrolysis, which provides the chemical-free energy to drive the molecular processes underlying cardiac pumping. Physiological rates of myocardial ATP consumption require the heart to resynthesize its entire ATP pool several times per minute. In the failing heart, cardiomyocyte metabolic dysfunction leads to a reduction in the capacity for ATP synthesis and associated free energy to drive cellular processes. Yet it remains unclear if and how metabolic/energetic dysfunction that occurs during heart failure affects mechanical function of the heart. We hypothesize that changes in phosphate metabolite concentrations (ATP, ADP, inorganic phosphate) that are associated with decompensation and failure have direct roles in impeding contractile function of the myocardium in heart failure, contributing to the whole-body phenotype. To test this hypothesis, a transverse aortic constriction (TAC) rat model of pressure overload, hypertrophy, and decompensation was used to assess relationships between metrics of whole-organ pump function and myocardial energetic state. A multiscale computational model of cardiac mechanoenergetic coupling was used to identify and quantify the contribution of metabolic dysfunction to observed mechanical dysfunction. Results show an overall reduction in capacity for oxidative ATP synthesis fueled by either fatty acid or carbohydrate substrates as well as a reduction in total levels of adenine nucleotides and creatine in myocardium from TAC animals compared to sham-operated controls. Changes in phosphate metabolite levels in the TAC rats are correlated with impaired mechanical function, consistent with the overall hypothesis. Furthermore, computational analysis of myocardial metabolism and contractile dynamics predicts that increased levels of inorganic phosphate in TAC compared to control animals kinetically impair the myosin ATPase crossbridge cycle in decompensated hypertrophy/heart failure.
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Affiliation(s)
- Rachel Lopez
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Bahador Marzban
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Xin Gao
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Ellen Lauinger
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Françoise Van den Bergh
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Steven E Whitesall
- Frankel Cardiovascular Center Physiology and Phenotyping Core, University of Michigan, Ann Arbor, MI, USA
| | - Kimber Converso-Baran
- Frankel Cardiovascular Center Physiology and Phenotyping Core, University of Michigan, Ann Arbor, MI, USA
| | - Charles F Burant
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Daniel E Michele
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA,Frankel Cardiovascular Center Physiology and Phenotyping Core, University of Michigan, Ann Arbor, MI, USA
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA,Address correspondence to D.A.B. (e-mail: )
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23
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Abstract
Anaplerosis and the associated mitochondrial metabolite transporters generate unique cytosolic metabolic signaling molecules that can regulate insulin release from pancreatic β-cells. It has been shown that mitochondrial metabolites, transported by the citrate carrier (CIC), dicarboxylate carrier (DIC), oxoglutarate carrier (OGC), and mitochondrial pyruvate carrier (MPC) play a vital role in the regulation of glucose-stimulated insulin secretion (GSIS). Metabolomic studies on static and biphasic insulin secretion, suggests that several anaplerotic derived metabolites, including α-ketoglutarate (αKG), are strongly associated with nutrient regulated insulin secretion. Support for a role of αKG in the regulation of insulin secretion comes from studies looking at αKG dependent enzymes, including hypoxia-inducible factor-prolyl hydroxylases (PHDs) in clonal β-cells, and rodent and human islets. This review will focus on the possible link between defective anaplerotic-derived αKG, PHDs, and the development of type 2 diabetes (T2D).
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Affiliation(s)
- M. Hoang
- School of Pharmacy, University of Waterloo, Kitchener, Ontario, Canada
| | - J. W. Joseph
- School of Pharmacy, University of Waterloo, Kitchener, Ontario, Canada
- CONTACT J. W. Joseph School of Pharmacy, University of Waterloo, Kitchener, ONN2G1C5, Canada
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24
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Zhao Y, Shen Y, Wen Y, Campbell RE. High-Performance Intensiometric Direct- and Inverse-Response Genetically Encoded Biosensors for Citrate. ACS CENTRAL SCIENCE 2020; 6:1441-1450. [PMID: 32875085 PMCID: PMC7453566 DOI: 10.1021/acscentsci.0c00518] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Indexed: 05/02/2023]
Abstract
Motivated by the growing recognition of citrate as a central metabolite in a variety of biological processes associated with healthy and diseased cellular states, we have developed a series of high-performance genetically encoded citrate biosensors suitable for imaging of citrate concentrations in mammalian cells. The design of these biosensors was guided by structural studies of the citrate-responsive sensor histidine kinase and took advantage of the same conformational changes proposed to propagate from the binding domain to the catalytic domain. Following extensive engineering based on a combination of structure guided mutagenesis and directed evolution, we produced an inverse-response biosensor (ΔF/F min ≈ 18) designated Citroff1 and a direct-response biosensor (ΔF/F min ≈ 9) designated Citron1. We report the X-ray crystal structure of Citron1 and demonstrate the utility of both biosensors for qualitative and quantitative imaging of steady-state and pharmacologically perturbed citrate concentrations in live cells.
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Affiliation(s)
- Yufeng Zhao
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yi Shen
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yurong Wen
- Department
of Talent Highland, The First Affiliated
Hospital, Xi’an Jiaotong University, Xi’an, Shaanxi 710061, China
- . (Y.W.; regarding x-ray crystallography)
| | - Robert E. Campbell
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
- . (R.E.C.)
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25
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Davis FM, denDekker A, Kimball A, Joshi AD, El Azzouny M, Wolf SJ, Obi AT, Lipinski J, Gudjonsson JE, Xing X, Plazyo O, Audu C, Melvin WJ, Singer K, Henke PK, Moore BB, Burant C, Kunkel SL, Gallagher KA. Epigenetic Regulation of TLR4 in Diabetic Macrophages Modulates Immunometabolism and Wound Repair. THE JOURNAL OF IMMUNOLOGY 2020; 204:2503-2513. [PMID: 32205424 DOI: 10.4049/jimmunol.1901263] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/21/2020] [Indexed: 12/17/2022]
Abstract
Macrophages are critical for the initiation and resolution of the inflammatory phase of wound healing. In diabetes, macrophages display a prolonged inflammatory phenotype preventing tissue repair. TLRs, particularly TLR4, have been shown to regulate myeloid-mediated inflammation in wounds. We examined macrophages isolated from wounds of patients afflicted with diabetes and healthy controls as well as a murine diabetic model demonstrating dynamic expression of TLR4 results in altered metabolic pathways in diabetic macrophages. Further, using a myeloid-specific mixed-lineage leukemia 1 (MLL1) knockout (Mll1f/fLyz2Cre+ ), we determined that MLL1 drives Tlr4 expression in diabetic macrophages by regulating levels of histone H3 lysine 4 trimethylation on the Tlr4 promoter. Mechanistically, MLL1-mediated epigenetic alterations influence diabetic macrophage responsiveness to TLR4 stimulation and inhibit tissue repair. Pharmacological inhibition of the TLR4 pathway using a small molecule inhibitor (TAK-242) as well as genetic depletion of either Tlr4 (Tlr4-/- ) or myeloid-specific Tlr4 (Tlr4f/fLyz2Cre+) resulted in improved diabetic wound healing. These results define an important role for MLL1-mediated epigenetic regulation of TLR4 in pathologic diabetic wound repair and suggest a target for therapeutic manipulation.
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Affiliation(s)
- Frank M Davis
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Aaron denDekker
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Andrew Kimball
- Section of Vascular Surgery, Department of Surgery, University of Alabama Birmingham, Birmingham, AL 35233
| | - Amrita D Joshi
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | | | - Sonya J Wolf
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Andrea T Obi
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Jay Lipinski
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109
| | | | - Xianying Xing
- Department of Dermatology, University of Michigan, Ann Arbor, MI 48109
| | - Olesya Plazyo
- Department of Dermatology, University of Michigan, Ann Arbor, MI 48109
| | - Christopher Audu
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - William J Melvin
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Kanakadurga Singer
- Section of Endocrinology, Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109
| | - Peter K Henke
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Bethany B Moore
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109; and.,Department Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109
| | - Charles Burant
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109; and
| | - Steven L Kunkel
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109
| | - Katherine A Gallagher
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI 48109; .,Department Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109
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26
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Metabolomics Analysis of Nutrient Metabolism in β-Cells. J Mol Biol 2020; 432:1429-1445. [DOI: 10.1016/j.jmb.2019.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/03/2019] [Accepted: 07/11/2019] [Indexed: 01/05/2023]
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27
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Prentki M, Corkey BE, Madiraju SRM. Lipid-associated metabolic signalling networks in pancreatic beta cell function. Diabetologia 2020; 63:10-20. [PMID: 31423551 DOI: 10.1007/s00125-019-04976-w] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/29/2019] [Indexed: 01/01/2023]
Abstract
Significant advances have been made in deciphering the mechanisms underlying fuel-stimulated insulin secretion by pancreatic beta cells. The contribution of the triggering/ATP-sensitive potassium (KATP)-dependent Ca2+ signalling and KATP-independent amplification pathways, that include anaplerosis and lipid signalling of glucose-stimulated insulin secretion (GSIS), are well established. A proposed model included a key role for a metabolic partitioning 'switch', the acetyl-CoA carboxylase (ACC)/malonyl-CoA/carnitine palmitoyltransferase-1 (CPT-1) axis, in beta cell glucose and fatty acid signalling for insulin secretion. This model has gained overwhelming support from a number of studies in recent years and is now refined through its link to the glycerolipid/NEFA cycle that provides lipid signals through its lipolysis arm. Furthermore, acetyl-CoA carboxylase may also control beta cell growth. Here we review the evidence supporting a role for the ACC/malonyl-CoA/CPT-1 axis in the control of GSIS and its particular importance under conditions of elevated fatty acids (e.g. fasting, excess nutrients, hyperlipidaemia and diabetes). We also document how it is linked to a more global lipid signalling system that includes the glycerolipid/NEFA cycle.
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Affiliation(s)
- Marc Prentki
- Department of Nutrition, University of Montreal, Montréal, QC, Canada.
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montréal, QC, Canada.
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Viger Tour, 900 rue Saint Denis, Room R08-412, Montréal, QC, H2X 0A9, Canada.
| | - Barbara E Corkey
- Evans Department of Medicine, Obesity Research Center, Boston University School of Medicine, Boston, MA, USA
| | - S R Murthy Madiraju
- Department of Nutrition, University of Montreal, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, University of Montreal, Montréal, QC, Canada
- Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Viger Tour, 900 rue Saint Denis, Room R08-412, Montréal, QC, H2X 0A9, Canada
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28
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Wortham M, Benthuysen JR, Wallace M, Savas JN, Mulas F, Divakaruni AS, Liu F, Albert V, Taylor BL, Sui Y, Saez E, Murphy AN, Yates JR, Metallo CM, Sander M. Integrated In Vivo Quantitative Proteomics and Nutrient Tracing Reveals Age-Related Metabolic Rewiring of Pancreatic β Cell Function. Cell Rep 2019; 25:2904-2918.e8. [PMID: 30517875 PMCID: PMC6317899 DOI: 10.1016/j.celrep.2018.11.031] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 09/06/2018] [Accepted: 11/05/2018] [Indexed: 01/02/2023] Open
Abstract
Pancreatic β cell physiology changes substantially throughout life, yet the mechanisms that drive these changes are poorly understood. Here, we performed comprehensive in vivo quantitative proteomic profiling of pancreatic islets from juvenile and 1-year-old mice. The analysis revealed striking differences in abundance of enzymes controlling glucose metabolism. We show that these changes in protein abundance are associated with higher activities of glucose metabolic enzymes involved in coupling factor generation as well as increased activity of the coupling factor-dependent amplifying pathway of insulin secretion. Nutrient tracing and targeted metabolomics demonstrated accelerated accumulation of glucose-derived metabolites and coupling factors in islets from 1-year-old mice, indicating that age-related changes in glucose metabolism contribute to improved glucose-stimulated insulin secretion with age. Together, our study provides an in-depth characterization of age-related changes in the islet proteome and establishes metabolic rewiring as an important mechanism for age-associated changes in β cell function. Organismal age impacts fundamental aspects of β cell physiology. Wortham et al. apply proteomics and targeted metabolomics to islets from juvenile and adult mice, revealing age-related changes in metabolic enzyme abundance and production of coupling factors that enhance insulin secretion. This work provides insight into age-associated changes to the β cell.
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Affiliation(s)
- Matthew Wortham
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jacqueline R Benthuysen
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Martina Wallace
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92037, USA
| | - Jeffrey N Savas
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Francesca Mulas
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ajit S Divakaruni
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - Fenfen Liu
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Verena Albert
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Brandon L Taylor
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yinghui Sui
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Enrique Saez
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, USA
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Christian M Metallo
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92037, USA
| | - Maike Sander
- Departments of Pediatrics and Cellular & Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093, USA.
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29
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Wishart DS. Metabolomics for Investigating Physiological and Pathophysiological Processes. Physiol Rev 2019; 99:1819-1875. [PMID: 31434538 DOI: 10.1152/physrev.00035.2018] [Citation(s) in RCA: 498] [Impact Index Per Article: 99.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Metabolomics uses advanced analytical chemistry techniques to enable the high-throughput characterization of metabolites from cells, organs, tissues, or biofluids. The rapid growth in metabolomics is leading to a renewed interest in metabolism and the role that small molecule metabolites play in many biological processes. As a result, traditional views of metabolites as being simply the "bricks and mortar" of cells or just the fuel for cellular energetics are being upended. Indeed, metabolites appear to have much more varied and far more important roles as signaling molecules, immune modulators, endogenous toxins, and environmental sensors. This review explores how metabolomics is yielding important new insights into a number of important biological and physiological processes. In particular, a major focus is on illustrating how metabolomics and discoveries made through metabolomics are improving our understanding of both normal physiology and the pathophysiology of many diseases. These discoveries are yielding new insights into how metabolites influence organ function, immune function, nutrient sensing, and gut physiology. Collectively, this work is leading to a much more unified and system-wide perspective of biology wherein metabolites, proteins, and genes are understood to interact synergistically to modify the actions and functions of organelles, organs, and organisms.
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Affiliation(s)
- David S Wishart
- Departments of Biological Sciences and Computing Science, University of Alberta, Edmonton, Alberta, Canada
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30
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Beck R, Chandi M, Kanke M, Stýblo M, Sethupathy P. Arsenic is more potent than cadmium or manganese in disrupting the INS-1 beta cell microRNA landscape. Arch Toxicol 2019; 93:3099-3109. [PMID: 31555879 DOI: 10.1007/s00204-019-02574-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/17/2019] [Indexed: 12/18/2022]
Abstract
Diabetes is a metabolic disorder characterized by fasting hyperglycemia and impaired glucose tolerance. Laboratory and population studies have shown that inorganic arsenic (iAs) can impair these pathways. Other metals including cadmium (Cd) and manganese (Mn) have also been linked to diabetes phenotypes. MicroRNAs, short non-coding RNAs that regulate gene expression, have emerged as potential drivers of metabolic dysfunction. MicroRNAs responsive to metal exposures in vitro have also been reported in independent studies to regulate insulin secretion in vivo. We hypothesize that microRNA dysregulation may associate with and possibly contribute to insulin secretion impairment upon exposure to iAs, Cd, or Mn. We exposed insulin secreting rat insulinoma cells to non-cytotoxic concentrations of iAs (1 µM), Cd (5 µM), and Mn (25 µM) for 24 h followed by small RNA sequencing to identify dysregulated microRNAs. RNA sequencing was then performed to further investigate changes in gene expression caused by iAs exposure. While all three metals significantly inhibited glucose-stimulated insulin secretion, high-throughput sequencing revealed distinct microRNA profiles specific to each exposure. One of the most significantly upregulated microRNAs post-iAs treatment is miR-146a (~ + 2-fold), which is known to be activated by nuclear factor κB (NF-κB) signaling. Accordingly, we found by RNA-seq analysis that genes upregulated by iAs exposure are enriched in the NF-κB signaling pathway and genes down-regulated by iAs exposure are enriched in miR-146a binding sites and are involved in regulating beta cell function. Notably, iAs exposure caused a significant decrease in the expression of Camk2a, a calcium-dependent protein kinase that regulates insulin secretion, has been implicated in type 2 diabetes, and is a likely target of miR-146a. Further studies are needed to elucidate potential interactions among NF-kB, miR-146a, and Camk2a in the context of iAs exposure.
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Affiliation(s)
- Rowan Beck
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Mohit Chandi
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Matt Kanke
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - Miroslav Stýblo
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Praveen Sethupathy
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
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31
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Zhang Q, Pan Y, Zeng B, Zheng X, Wang H, Shen X, Li H, Jiang Q, Zhao J, Meng ZX, Li P, Chen Z, Wei H, Liu Z. Intestinal lysozyme liberates Nod1 ligands from microbes to direct insulin trafficking in pancreatic beta cells. Cell Res 2019; 29:516-532. [PMID: 31201384 PMCID: PMC6796897 DOI: 10.1038/s41422-019-0190-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/21/2019] [Indexed: 02/06/2023] Open
Abstract
Long-range communication between intestinal symbiotic bacteria and extra-intestinal organs can occur through circulating bacterial signal molecules, through neural circuits, or through cytokines or hormones from host cells. Here we report that Nod1 ligands derived from intestinal bacteria act as signal molecules and directly modulate insulin trafficking in pancreatic beta cells. The cytosolic peptidoglycan receptor Nod1 and its downstream adapter Rip2 are required for insulin trafficking in beta cells in a cell-autonomous manner. Mechanistically, upon recognizing cognate ligands, Nod1 and Rip2 localize to insulin vesicles, recruiting Rab1a to direct insulin trafficking through the cytoplasm. Importantly, intestinal lysozyme liberates Nod1 ligands into the circulation, thus enabling long-range communication between intestinal microbes and islets. The intestine-islet crosstalk bridged by Nod1 ligands modulates host glucose tolerance. Our study defines a new type of inter-organ communication based on circulating bacterial signal molecules, which has broad implications for understanding the mutualistic relationship between microbes and host.
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Affiliation(s)
- Qin Zhang
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying Pan
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Benhua Zeng
- Department of Laboratory Animal Science, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038, China
| | - Xiaojiao Zheng
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Haifang Wang
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xueying Shen
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hui Li
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qian Jiang
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Jiaxu Zhao
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Rd, Shanghai, 200031, China.,Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, 320 Yueyang Rd, Shanghai, 200031, China
| | - Zhuo-Xian Meng
- Department of Pathology and Pathophysiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Pingping Li
- The State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Zhengjun Chen
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Rd, Shanghai, 200031, China.,Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, 320 Yueyang Rd, Shanghai, 200031, China.,ShanghaiTech Univ, Sch Life Sci & Technol, 100 Haike Rd, Shanghai, 201210, China
| | - Hong Wei
- Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510080, China.
| | - Zhihua Liu
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. .,Center for Excellence in Biomacromolecules, Chinese Academy of Sciences, Beijing, 100101, China.
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32
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Imai Y, Cousins RS, Liu S, Phelps BM, Promes JA. Connecting pancreatic islet lipid metabolism with insulin secretion and the development of type 2 diabetes. Ann N Y Acad Sci 2019; 1461:53-72. [PMID: 30937918 DOI: 10.1111/nyas.14037] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/24/2019] [Accepted: 01/30/2019] [Indexed: 02/06/2023]
Abstract
Obesity is the major contributing factor for the increased prevalence of type 2 diabetes (T2D) in recent years. Sustained positive influx of lipids is considered to be a precipitating factor for beta cell dysfunction and serves as a connection between obesity and T2D. Importantly, fatty acids (FA), a key building block of lipids, are a double-edged sword for beta cells. FA acutely increase glucose-stimulated insulin secretion through cell-surface receptor and intracellular pathways. However, chronic exposure to FA, combined with elevated glucose, impair the viability and function of beta cells in vitro and in animal models of obesity (glucolipotoxicity), providing an experimental basis for the propensity of beta cell demise under obesity in humans. To better understand the two-sided relationship between lipids and beta cells, we present a current view of acute and chronic handling of lipids by beta cells and implications for beta cell function and health. We also discuss an emerging role for lipid droplets (LD) in the dynamic regulation of lipid metabolism in beta cells and insulin secretion, along with a potential role for LD under nutritional stress in beta cells, and incorporate recent advancement in the field of lipid droplet biology.
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Affiliation(s)
- Yumi Imai
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
| | - Ryan S Cousins
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia
| | - Siming Liu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
| | - Brian M Phelps
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia
| | - Joseph A Promes
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
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33
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Lamontagne J, Al-Mass A, Nolan CJ, Corkey BE, Madiraju SRM, Joly E, Prentki M. Identification of the signals for glucose-induced insulin secretion in INS1 (832/13) β-cells using metformin-induced metabolic deceleration as a model. J Biol Chem 2017; 292:19458-19468. [PMID: 28972173 DOI: 10.1074/jbc.m117.808105] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/13/2017] [Indexed: 12/23/2022] Open
Abstract
Metabolic deceleration in pancreatic β-cells is associated with inhibition of glucose-induced insulin secretion (GIIS), but only in the presence of intermediate/submaximal glucose concentrations. Here, we used acute metformin treatment as a tool to induce metabolic deceleration in INS1 (832/13) β-cells, with the goal of identifying key pathways and metabolites involved in GIIS. Metabolites and pathways previously implicated as signals for GIIS were measured in the cells at 2-25 mm glucose, with or without 5 mm metformin. We defined three criteria to identify candidate signals: 1) glucose-responsiveness, 2) sensitivity to metformin-induced inhibition of the glucose effect at intermediate glucose concentrations, and 3) alleviation of metformin inhibition by elevated glucose concentrations. Despite the lack of recovery from metformin-induced impairment of mitochondrial energy metabolism (glucose oxidation, O2 consumption, and ATP production), insulin secretion was almost completely restored at elevated glucose concentrations. Meeting the criteria for candidates involved in promoting GIIS were the following metabolic indicators and metabolites: cytosolic NAD+/NADH ratio (inferred from the dihydroxyacetone phosphate:glycerol-3-phosphate ratio), mitochondrial membrane potential, ADP, Ca2+, 1-monoacylglycerol, diacylglycerol, malonyl-CoA, and HMG-CoA. On the contrary, most of the purine and nicotinamide nucleotides, acetoacetyl-CoA, H2O2, reduced glutathione, and 2-monoacylglycerol were not glucose-responsive. Overall these results underscore the significance of mitochondrial energy metabolism-independent signals in GIIS regulation; in particular, the candidate lipid signaling molecules 1-monoacylglycerol, diacylglycerol, and malonyl-CoA; the predominance of KATP/Ca2+ signaling control by low ADP·Mg2+ rather than by high ATP levels; and a role for a more oxidized state (NAD+/NADH) in the cytosol during GIIS that favors high glycolysis rates.
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Affiliation(s)
- Julien Lamontagne
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada
| | - Anfal Al-Mass
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada.,the Department of Medicine, McGill University, Montréal, Québec H4A 3J1, Canada
| | - Christopher J Nolan
- the Department of Endocrinology, Canberra Hospital and the Medical School, Australian National University, Canberra ACT 2605, Australia, and
| | - Barbara E Corkey
- the Department of Medicine, Obesity Research Center, Boston University School of Medicine, Boston, Massachusetts 02118
| | - S R Murthy Madiraju
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada
| | - Erik Joly
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada
| | - Marc Prentki
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada, .,the Departments of Nutrition and Biochemistry, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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34
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Lawlor N, Youn A, Kursawe R, Ucar D, Stitzel ML. Alpha TC1 and Beta-TC-6 genomic profiling uncovers both shared and distinct transcriptional regulatory features with their primary islet counterparts. Sci Rep 2017; 7:11959. [PMID: 28931935 PMCID: PMC5607285 DOI: 10.1038/s41598-017-12335-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/06/2017] [Indexed: 01/09/2023] Open
Abstract
Alpha TC1 (αTC1) and Beta-TC-6 (βTC6) mouse islet cell lines are cellular models of islet (dys)function and type 2 diabetes (T2D). However, genomic characteristics of these cells, and their similarities to primary islet alpha and beta cells, are undefined. Here, we report the epigenomic (ATAC-seq) and transcriptomic (RNA-seq) landscapes of αTC1 and βTC6 cells. Each cell type exhibits hallmarks of its primary islet cell counterpart including cell-specific expression of beta (e.g., Pdx1) and alpha (e.g., Arx) cell transcription factors (TFs), and enrichment of binding motifs for these TFs in αTC1/βTC6 cis-regulatory elements. αTC1/βTC6 transcriptomes overlap significantly with the transcriptomes of primary mouse/human alpha and beta cells. Our data further indicate that ATAC-seq detects cell-specific regulatory elements for cell types comprising ≥ 20% of a mixed cell population. We identified αTC1/βTC6 cis-regulatory elements orthologous to those containing type 2 diabetes (T2D)-associated SNPs in human islets for 33 loci, suggesting these cells’ utility to dissect T2D molecular genetics in these regions. Together, these maps provide important insights into the conserved regulatory architecture between αTC1/βTC6 and primary islet cells that can be leveraged in functional (epi)genomic approaches to dissect the genetic and molecular factors controlling islet cell identity and function.
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Affiliation(s)
- Nathan Lawlor
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Ahrim Youn
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Romy Kursawe
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Duygu Ucar
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, 06032, USA. .,Department of Genetics & Genome Sciences, University of Connecticut, Farmington, CT, 06032, USA.
| | - Michael L Stitzel
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, 06032, USA. .,Department of Genetics & Genome Sciences, University of Connecticut, Farmington, CT, 06032, USA.
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35
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Kowluru A. Role of G-proteins in islet function in health and diabetes. Diabetes Obes Metab 2017; 19 Suppl 1:63-75. [PMID: 28880478 PMCID: PMC5657296 DOI: 10.1111/dom.13011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/03/2017] [Accepted: 05/12/2017] [Indexed: 12/17/2022]
Abstract
Glucose-stimulated insulin secretion (GSIS) involves interplay between metabolic and cationic events. Seminal contributions from multiple laboratories affirm essential roles for small G-proteins (Rac1, Cdc42, Arf6, Rab27A) in GSIS. Activation of these signalling proteins promotes cytoskeletal remodeling, transport and docking of insulin granules on the plasma membrane for exocytotic secretion of insulin. Evidence in rodent and human islets suggests key roles for lipidation (farnesylation and geranylgeranylation) of these G-proteins for their targeting to appropriate cellular compartments for optimal regulation of effectors leading to GSIS. Interestingly, however, inhibition of prenylation appears to cause mislocalization of non-prenylated, but (paradoxically) activated G-proteins, in "inappropriate" compartments leading to activation of stress kinases and onset of mitochondrial defects, loss in GSIS and apoptosis of the islet β-cell. This review highlights our current understanding of roles of G-proteins and their post-translational lipidation (prenylation) signalling networks in islet function in normal health, metabolic stress (glucolipotoxicity and ER stress) and diabetes. Critical knowledge gaps that need to be addressed for the development of therapeutics to halt defects in these signalling steps in β-cells in models of impaired insulin secretion and diabetes are also highlighted and discussed.
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Affiliation(s)
- Anjaneyulu Kowluru
- β-Cell Biochemistry Laboratory, John D. Dingell VA Medical Center, and Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan
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36
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Jensen MV, Gooding J, Ferdaoussi M, Dai XQ, MacDonald PE, Newgard CB. Metabolomics applied to islet nutrient sensing mechanisms. Diabetes Obes Metab 2017; 19 Suppl 1:90-94. [PMID: 28880482 PMCID: PMC5929146 DOI: 10.1111/dom.13010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/09/2017] [Accepted: 05/12/2017] [Indexed: 12/16/2022]
Abstract
After multiple decades of investigation, the precise mechanisms involved in fuel-stimulated insulin secretion are still being revealed. One avenue for gaining deeper knowledge is to apply emergent tools of "metabolomics," involving mass spectrometry and nuclear magnetic resonance-based profiling of islet cells in their fuel-stimulated compared with basal states. The current article summarizes recent insights gained from application of metabolomics tools to the specific process of glucose-stimulated insulin secretion, revealing 2 new mechanisms that may provide targets for improving insulin secretion in diabetes.
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Affiliation(s)
- Mette V. Jensen
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701
| | - Jessica Gooding
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701
| | - Mourad Ferdaoussi
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada, T6G2R3
| | - Xiao-Qing Dai
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada, T6G2R3
| | - Patrick E. MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada, T6G2R3
| | - Christopher B. Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701
- Corresponding Author: Christopher B. Newgard, PhD, Duke Molecular Physiology Institute, 300 North Duke Street, Durham, NC 27701, , Phone: (919) 668-6059
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37
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Garcia-Contreras M, Tamayo-Garcia A, Pappan KL, Michelotti GA, Stabler CL, Ricordi C, Buchwald P. Metabolomics Study of the Effects of Inflammation, Hypoxia, and High Glucose on Isolated Human Pancreatic Islets. J Proteome Res 2017; 16:2294-2306. [PMID: 28452488 PMCID: PMC5557342 DOI: 10.1021/acs.jproteome.7b00160] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The transplantation of human pancreatic islets is a therapeutic possibility for a subset of type 1 diabetic patients who experience severe hypoglycemia. Pre- and post-transplantation loss in islet viability and function, however, is a major efficacy-limiting impediment. To investigate the effects of inflammation and hypoxia, the main obstacles hampering the survival and function of isolated, cultured, and transplanted islets, we conducted a comprehensive metabolomics evaluation of human islets in parallel with dynamic glucose-stimulated insulin release (GSIR) perifusion studies for functional evaluation. Metabolomics profiling of media and cell samples identified a total of 241 and 361 biochemicals, respectively. Metabolites that were altered in highly significant manner in both included, for example, kynurenine, kynurenate, citrulline, and mannitol/sorbitol under inflammation (all elevated) plus lactate (elevated) and N-formylmethionine (depressed) for hypoxia. Dynamic GSIR experiments, which capture both first- and second-phase insulin release, found severely depressed insulin-secretion under hypoxia, whereas elevated baseline and stimulated insulin-secretion was measured for islet exposed to the inflammatory cytokine cocktail (IL-1β, IFN-γ, and TNF-α). Because of the uniquely large changes observed in kynurenine and kynurenate, they might serve as potential biomarkers of islet inflammation, and indoleamine-2,3-dioxygenase on the corresponding pathway could be a worthwhile therapeutic target to dampen inflammatory effects.
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Affiliation(s)
- Marta Garcia-Contreras
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Ri.Med, Palermo, Italy
- Catholyc University of Valencia, Valencia, Spain
| | | | | | | | - Cherie L. Stabler
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Camillo Ricordi
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Ri.Med, Palermo, Italy
| | - Peter Buchwald
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
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38
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Abstract
Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.
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Affiliation(s)
- Michael A Kalwat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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39
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ElAzzouny M, Tom CTMB, Evans CR, Olson LL, Tanga MJ, Gallagher KA, Martin BR, Burant CF. Dimethyl Itaconate Is Not Metabolized into Itaconate Intracellularly. J Biol Chem 2017; 292:4766-4769. [PMID: 28188288 PMCID: PMC5377792 DOI: 10.1074/jbc.c117.775270] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/07/2017] [Indexed: 01/12/2023] Open
Abstract
Itaconic acid is an important metabolite produced by macrophages after stimulation with LPS. The role of itaconate in the inflammatory cascade is unclear. Here we used [13C]itaconate and dimethyl [13C]itaconate (DMI) to probe itaconate metabolism, and find that [13C]DMI is not metabolized to itaconate. [13C]Itaconate in the cell culture medium leads to elevated intracellular levels of unlabeled succinate, with no evidence of intracellular uptake. The goal of this study is to encourage the development of effective pro-drug strategies to increase the intracellular levels of itaconate, which will enable more conclusive analysis of its action on macrophages and other cell and tissue types.
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40
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Mugabo Y, Zhao S, Lamontagne J, Al-Mass A, Peyot ML, Corkey BE, Joly E, Madiraju SRM, Prentki M. Metabolic fate of glucose and candidate signaling and excess-fuel detoxification pathways in pancreatic β-cells. J Biol Chem 2017; 292:7407-7422. [PMID: 28280244 DOI: 10.1074/jbc.m116.763060] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 03/06/2017] [Indexed: 12/28/2022] Open
Abstract
Glucose metabolism promotes insulin secretion in β-cells via metabolic coupling factors that are incompletely defined. Moreover, chronically elevated glucose causes β-cell dysfunction, but little is known about how cells handle excess fuels to avoid toxicity. Here we sought to determine which among the candidate pathways and coupling factors best correlates with glucose-stimulated insulin secretion (GSIS), define the fate of glucose in the β-cell, and identify pathways possibly involved in excess-fuel detoxification. We exposed isolated rat islets for 1 h to increasing glucose concentrations and measured various pathways and metabolites. Glucose oxidation, oxygen consumption, and ATP production correlated well with GSIS and saturated at 16 mm glucose. However, glucose utilization, glycerol release, triglyceride and glycogen contents, free fatty acid (FFA) content and release, and cholesterol and cholesterol esters increased linearly up to 25 mm glucose. Besides being oxidized, glucose was mainly metabolized via glycerol production and release and lipid synthesis (particularly FFA, triglycerides, and cholesterol), whereas glycogen production was comparatively low. Using targeted metabolomics in INS-1(832/13) cells, we found that several metabolites correlated well with GSIS, in particular some Krebs cycle intermediates, malonyl-CoA, and lower ADP levels. Glucose dose-dependently increased the dihydroxyacetone phosphate/glycerol 3-phosphate ratio in INS-1(832/13) cells, indicating a more oxidized state of NAD in the cytosol upon glucose stimulation. Overall, the data support a role for accelerated oxidative mitochondrial metabolism, anaplerosis, and malonyl-CoA/lipid signaling in β-cell metabolic signaling and suggest that a decrease in ADP levels is important in GSIS. The results also suggest that excess-fuel detoxification pathways in β-cells possibly comprise glycerol and FFA formation and release extracellularly and the diversion of glucose carbons to triglycerides and cholesterol esters.
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Affiliation(s)
- Yves Mugabo
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada.,Departments of Nutrition, Biochemistry and Molecular Medicine, Faculty of Medicine, University of Montréal, Montreal, Québec H3C 3J7, Canada, and
| | - Shangang Zhao
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada.,Departments of Medicine and Human Genetics, McGill University, Montreal, Québec H3A 1B1, Canada
| | - Julien Lamontagne
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
| | - Anfal Al-Mass
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada.,Departments of Medicine and Human Genetics, McGill University, Montreal, Québec H3A 1B1, Canada
| | - Marie-Line Peyot
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
| | - Barbara E Corkey
- Department of Medicine, Obesity Research Center, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Erik Joly
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
| | - S R Murthy Madiraju
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
| | - Marc Prentki
- From the Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada, .,Departments of Nutrition, Biochemistry and Molecular Medicine, Faculty of Medicine, University of Montréal, Montreal, Québec H3C 3J7, Canada, and
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Kuruvilla SP, Tiruchinapally G, ElAzzouny M, ElSayed MEH. N-Acetylgalactosamine-Targeted Delivery of Dendrimer-Doxorubicin Conjugates Influences Doxorubicin Cytotoxicity and Metabolic Profile in Hepatic Cancer Cells. Adv Healthc Mater 2017; 6. [PMID: 28085993 DOI: 10.1002/adhm.201601046] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/25/2016] [Indexed: 12/28/2022]
Abstract
This study describes the development of targeted, doxorubicin (DOX)-loaded generation 5 (G5) polyamidoamine dendrimers able to achieve cell-specific DOX delivery and release into the cytoplasm of hepatic cancer cells. G5 is functionalized with poly(ethylene glycol) (PEG) brushes displaying N-acetylgalactosamine (NAcGal) ligands to target hepatic cancer cells. DOX is attached to G5 through one of two aromatic azo-linkages, L3 or L4, achieving either P1 ((NAcGalβ -PEGc)16.6 -G5-(L3-DOX)11.6 ) or P2 ((NAcGalβ -PEGc)16.6 -G5-(L4-DOX)13.4 ) conjugates. After confirming the conjugates' biocompatibility, flow cytometry studies show P1/P2 achieve 100% uptake into hepatic cancer cells at 30-60 × 10-9 m particle concentration. This internalization correlates with cytotoxicity against HepG2 cells with 50% inhibitory concentration (IC50 ) values of 24.8, 1414.0, and 237.8 × 10-9 m for free DOX, P1, and P2, respectively. Differences in cytotoxicity prompted metabolomics analysis to identify the intracellular release behavior of DOX. Results show that P1/P2 release alternative DOX metabolites than free DOX. Stable isotope tracer studies show that the different metabolites induce different effects on metabolic cycles. Namely, free DOX reduces glycolysis and increases fatty acid oxidation, while P1/P2 increase glycolysis, likely as a response to high oxidative stress. Overall, P1/P2 conjugates offer a platform drug delivery technology for improving hepatic cancer therapy.
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Affiliation(s)
- Sibu P. Kuruvilla
- Department of Materials Science and Engineering University of Michigan 2300 Hayward St. Ann Arbor MI 48109 USA
| | - Gopinath Tiruchinapally
- Department of Biomedical Engineering University of Michigan 1101 Beal Avenue Ann Arbor MI 48109 USA
| | - Mahmoud ElAzzouny
- Department of Internal Medicine University of Michigan Medical School 1500 East Medical Center Drive Ann Arbor MI 48109 USA
| | - Mohamed E. H. ElSayed
- Department of Biomedical Engineering University of Michigan 1101 Beal Avenue Ann Arbor MI 48109 USA
- Department of Macromolecular Science and Engineering University of Michigan 2300 Hayward Avenue Ann Arbor MI 48109 USA
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Schulze T, Morsi M, Reckers K, Brüning D, Seemann N, Panten U, Rustenbeck I. Metabolic amplification of insulin secretion is differentially desensitized by depolarization in the absence of exogenous fuels. Metabolism 2017; 67:1-13. [PMID: 28081772 DOI: 10.1016/j.metabol.2016.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The metabolic amplification of insulin secretion is the sequence of events which enables the secretory response to a fuel secretagogue to exceed the secretory response to a purely depolarizing stimulus. The signals in this pathway are incompletely understood. Here, we have characterized an experimental procedure by which the amplifying response to glucose is reversibly desensitized, while the response to α-ketoisocaproic acid (KIC) is unchanged. MATERIALS/METHODS Insulin secretion, NAD(P)H- and FAD-autofluorescence, Fura-2 fluorescence and oxygen consumption were measured in perifused NMRI mouse islets. The ATP- and ADP-contents were measured in statically incubated mouse islets. All islets were freshly isolated. RESULTS While the original observation on the dissociation between glucose- and KIC-amplification was obtained with islets that had been exposed to a high concentration of the sulfonylurea glipizide in the absence of glucose, we now show that in the absence of exogenous fuel a moderate depolarization, irrespective of its mechanism, progressively decreased the amplification in response to both glucose and KIC. However, the amplification in response to glucose declined faster, so a time window exists where glucose was already inefficient, whereas KIC was of unimpaired efficiency. Measurements of adenine nucleotides, NAD(P)H- and FAD-autofluorescence, and oxygen consumption point to a central role of the mitochondrial metabolism in this process. The desensitization could be quickly reversed by increasing oxidative deamination of glutamate and consequently anaplerosis of the citrate cycle. CONCLUSION Depolarization in the absence of exogenous fuel may be a useful model to identify those signals which are indispensable for the generation of metabolic amplification.
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Affiliation(s)
- Torben Schulze
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Mai Morsi
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Kirstin Reckers
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Dennis Brüning
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Nele Seemann
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Uwe Panten
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany.
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Abstract
Metabolomics, or the comprehensive profiling of small molecule metabolites in cells, tissues, or whole organisms, has undergone a rapid technological evolution in the past two decades. These advances have led to the application of metabolomics to defining predictive biomarkers for incident cardiometabolic diseases and, increasingly, as a blueprint for understanding those diseases' pathophysiologic mechanisms. Progress in this area and challenges for the future are reviewed here.
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Affiliation(s)
- Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Departments of Pharmacology & Cancer Biology and Medicine, Duke University Medical Center, Durham, NC 27701, USA.
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Phannasil P, Ansari IUH, El Azzouny M, Longacre MJ, Rattanapornsompong K, Burant CF, MacDonald MJ, Jitrapakdee S. Mass spectrometry analysis shows the biosynthetic pathways supported by pyruvate carboxylase in highly invasive breast cancer cells. Biochim Biophys Acta Mol Basis Dis 2016; 1863:537-551. [PMID: 27890529 DOI: 10.1016/j.bbadis.2016.11.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/28/2016] [Accepted: 11/22/2016] [Indexed: 12/22/2022]
Abstract
We recently showed that the anaplerotic enzyme pyruvate carboxylase (PC) is up-regulated in human breast cancer tissue and its expression is correlated with the late stages of breast cancer and tumor size [Phannasil et al., PloS One 10, e0129848, 2015]. In the current study we showed that PC enzyme activity is much higher in the highly invasive breast cancer cell line MDA-MB-231 than in less invasive breast cancer cell lines. We generated multiple stable PC knockdown cell lines from the MDA-MB-231 cell line and used mass spectrometry with 13C6-glucose and 13C5-glutamine to discern the pathways that use PC in support of cell growth. Cells with severe PC knockdown showed a marked reduction in viability and proliferation rates suggesting the perturbation of pathways that are involved in cancer invasiveness. Strong PC suppression lowered glucose incorporation into downstream metabolites of oxaloacetate, the product of the PC reaction, including malate, citrate and aspartate. Levels of pyruvate, lactate, the redox partner of pyruvate, and acetyl-CoA were also lower suggesting the impairment of mitochondrial pyruvate cycles. Serine, glycine and 5-carbon sugar levels and flux of glucose into fatty acids were decreased. ATP, ADP and NAD(H) levels were unchanged indicating that PC suppression did not significantly affect mitochondrial energy production. The data indicate that the major metabolic roles of PC in invasive breast cancer are primarily anaplerosis, pyruvate cycling and mitochondrial biosynthesis of precursors of cellular components required for breast cancer cell growth and replication.
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Affiliation(s)
- Phatchariya Phannasil
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Israr-Ul H Ansari
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Mahmoud El Azzouny
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Melissa J Longacre
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | | | - Charles F Burant
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Michael J MacDonald
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Sarawut Jitrapakdee
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
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Amin J, Ramachandran K, Williams SJ, Lee A, Novikova L, Stehno-Bittel L. A simple, reliable method for high-throughput screening for diabetes drugs using 3D β-cell spheroids. J Pharmacol Toxicol Methods 2016; 82:83-89. [DOI: 10.1016/j.vascn.2016.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/08/2016] [Accepted: 08/11/2016] [Indexed: 12/27/2022]
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Gerencser AA, Mookerjee SA, Jastroch M, Brand MD. Positive Feedback Amplifies the Response of Mitochondrial Membrane Potential to Glucose Concentration in Clonal Pancreatic Beta Cells. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1054-1065. [PMID: 27771512 DOI: 10.1016/j.bbadis.2016.10.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 02/07/2023]
Abstract
Analysis of the cellular mechanisms of metabolic disorders, including type 2 diabetes mellitus, is complicated by the large number of reactions and interactions in metabolic networks. Metabolic control analysis with appropriate modularization is a powerful method for simplifying and analyzing these networks. To analyze control of cellular energy metabolism in adherent cell cultures of the INS-1 832/13 pancreatic β-cell model we adapted our microscopy assay of absolute mitochondrial membrane potential (ΔψM) to a fluorescence microplate reader format, and applied it in conjunction with cell respirometry. In these cells the sensitive response of ΔψM to extracellular glucose concentration drives glucose-stimulated insulin secretion. Using metabolic control analysis we identified the control properties that generate this sensitive response. Force-flux relationships between ΔψM and respiration were used to calculate kinetic responses to ΔψM of processes both upstream (glucose oxidation) and downstream (proton leak and ATP turnover) of ΔψM. The analysis revealed that glucose-evoked ΔψM hyperpolarization is amplified by increased glucose oxidation activity caused by factors downstream of ΔψM. At high glucose, the hyperpolarized ΔψM is stabilized almost completely by the action of glucose oxidation, whereas proton leak also contributes to the homeostatic control of ΔψM at low glucose. These findings suggest a strong positive feedback loop in the regulation of β-cell energetics, and a possible regulatory role of proton leak in the fasting state. Analysis of islet bioenergetics from published cases of type 2 diabetes suggests that disruption of this feedback can explain the damaged bioenergetic response of β-cells to glucose. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.
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Affiliation(s)
- Akos A Gerencser
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Image Analyst Software, 43 Nova Lane, Novato, CA 94945, United States.
| | - Shona A Mookerjee
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Touro University California College of Pharmacy, 1310 Club Drive, Vallejo, CA 94592, United States
| | - Martin Jastroch
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States
| | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States
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Panten U, Früh E, Reckers K, Rustenbeck I. Acute metabolic amplification of insulin secretion in mouse islets: Role of cytosolic acetyl-CoA. Metabolism 2016; 65:1225-9. [PMID: 27506729 DOI: 10.1016/j.metabol.2016.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/20/2016] [Accepted: 05/05/2016] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Stimulation of the ß-cell metabolism by glucose and other fuels triggers insulin release by enhancing the mitochondrial ATP production and acutely amplifies the secretory response by increase in mitochondrial export of metabolites. We aimed to narrow down the uniform final reaction steps mediating fuel-induced acute amplification of insulin secretion. MATERIAL/METHODS Insulin secretion and metabolic parameters were measured in isolated mouse islets exposed to the sulfonylurea glipizide in high concentration (closing all ATP-sensitive K(+) channels) during the entire experiment. Fuel-induced effects were examined after treating the islets for one hour with medium devoid of fuels. This experimental design prevented acute amplification, but only when glucose was the sole fuel. RESULTS Strong amplification of insulin secretion by α-ketoisocaproate or glucose combined with α-ketoisovalerate (supplying mitochondrial oxaloacetate) was abolished within 14min after transition to medium devoid of fuels. After transition from medium containing glucose plus α-ketoisovalerate to medium containing solely glucose or α-ketoisovalerate, amplification (strong or weak, respectively) occurred until the end of the experiment. Glucose (alone or combined with α-ketoisovalerate) increased the total acetyl-CoA content as intensely as α-ketoisocaproate. Low concentrations of α-ketoisovalerate or α-ketoisocaproate were sufficient for saturation of acetyl-CoA increase, but caused no or only weak amplification, respectively. No acetyl-CoA increases occurred in the absence of glipizide. CONCLUSIONS Glucose and other fuels regulate acute amplification of insulin secretion by controlling the supply of acetyl-CoA to the ß-cell cytosol. Cytosolic acetyl-CoA does not amplify by serving as substrate for syntheses of metabolic intermediates, but amplifies by acting as substrate for cytosolic protein acetylation.
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Affiliation(s)
- Uwe Panten
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany.
| | - Eike Früh
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Kirstin Reckers
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
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Soliman GA, Steenson SM, Etekpo AH. Effects of Metformin and a Mammalian Target of Rapamycin (mTOR) ATP-Competitive Inhibitor on Targeted Metabolomics in Pancreatic Cancer Cell Line. ACTA ACUST UNITED AC 2016; 6. [PMID: 28217402 DOI: 10.4172/2153-0769.1000183] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pancreatic Cancer (PC) is a devastating lethal disease. Therefore, there is an urgent need to develop new intervention strategies. The mammalian Target of Rapamycin (mTOR) is a conserved kinase and master regulator of metabolism and cell growth. mTOR is dysregulated in chronic diseases including diabetes and pancreatic cancer. Recent reports indicate that 50% of Pancreatic Ductal Adenocarcinoma (PDAC) patients are diabetic at the time of diagnosis. Furthermore, the anti-diabetic drug, metformin, which indirectly inhibits mTOR, has emerged as a potential therapeutic target for PC. The objective of this study is to determine the targeted-metabolomics profile in PDAC cell line (HPAF-II) with mTOR inhibition and the interaction between mTOR ATP-competitive inhibitor (Torin 2) and metformin as potential combined therapy in PC. HPAF-II cell lines were cultured in the presence of either Torin 2, metformin, both, or control vehicle. We utilized targeted LC/MS/MS to characterize the alterations in glycolytic and tricarboxylic acid cycle metabolomics, and employed Western Blot analysis for cell signaling activation by phosphorylation. Comparisons between groups were analyzed using one-way Analysis of Variance followed by secondary post-hoc analysis. After 1 h incubation with metformin, AMP concentration was significantly increased compared to other groups (p<0.03). After 24 h, Torin-2 significantly decreased glycolysis intermediates (fructose 1,6-bisphosphate (FBP), and 2-phosphoglycerate/3-phosphoglycerate), TCA intermediate metabolites (citrate/isocitrate, and malate), as well as Nicotinamide Adenine Dinucleotide (NAD+) and Flavin Adenine Dinucleotide (FAD), and ATP levels. When HPAF-II cells were incubated with both Torin-2 and metformin, there was a significant reduction in NAD+ and FAD, suggesting decreased levels of the energy equivalents that are available to the electron transport chain. Targeted metabolomics data indicate that mTOR complexes inhibition by Torin 2 reduced glycolytic intermediates and TCA metabolites in HPAF- II and may synergize with metformin to decrease the electron acceptors NAD+ and FAD which may lead to reduced energy production.
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Affiliation(s)
- Ghada A Soliman
- Department of Health Promotion, Social and Behavioral Health College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, 68198 USA
| | - Sharalyn M Steenson
- Department of Health Promotion, Social and Behavioral Health College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, 68198 USA
| | - Asserewou H Etekpo
- Department of Health Promotion, Social and Behavioral Health College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, 68198 USA
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El Azzouny M, Longacre MJ, Ansari IUH, Kennedy RT, Burant CF, MacDonald MJ. Knockdown of ATP citrate lyase in pancreatic beta cells does not inhibit insulin secretion or glucose flux and implicates the acetoacetate pathway in insulin secretion. Mol Metab 2016; 5:980-987. [PMID: 27689010 PMCID: PMC5034614 DOI: 10.1016/j.molmet.2016.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 07/21/2016] [Accepted: 07/27/2016] [Indexed: 12/31/2022] Open
Abstract
Objective Glucose-stimulated insulin secretion in pancreatic beta cells requires metabolic signals including the generation of glucose-derived short chain acyl-CoAs in the cytosol from mitochondrially-derived metabolites. One concept of insulin secretion is that ATP citrate lyase generates short chain acyl-CoAs in the cytosol from mitochondrially-derived citrate. Of these, malonyl-CoA, is believed to be an important signal in insulin secretion. Malonyl-CoA is also a precursor for lipids. Our recent evidence suggested that, in the mitochondria of beta cells, glucose-derived pyruvate can be metabolized to acetoacetate that is exported to the cytosol and metabolized to the same short chain acyl-CoAs and fatty acids that can be derived from citrate. We tested for redundancy of the citrate pathway. Methods We inhibited ATP citrate lyase activity using hydroxycitrate as well as studying a stable cell line generated with shRNA knockdown of ATP citrate lyase in the pancreatic beta cell line INS-1 832/13. Results In both instances glucose-stimulated insulin release was not inhibited. Mass spectrometry analysis showed that the flux of carbon from [U-13C]glucose and/or [U-13C]α-ketoisocaproic acid (KIC) into short chain acyl-CoAs in cells with hydroxycitrate-inhibited ATP citrate lyase or in the cell line with stable severe (>90%) shRNA knockdown of ATP citrate lyase was similar to the controls. Both 13C-glucose and 13C-KIC introduced substantial 13C labeling into acetyl-CoA, malonyl-CoA, and HMG-CoA under both conditions. Glucose flux into fatty acids was not affected by ATP citrate lyase knockdown. Conclusion The results establish the involvement of the acetoacetate pathway in insulin secretion in pancreatic beta cells. In pancreatic beta cells mitochondria synthesize metabolites from glucose. Mitochondria-derived citrate and acetoacetate can transfer carbon to the cytosol. The citrate pathway requires ATP citrate lyase (ACLY). Inhibition of ACLY did not stop metabolite export to the cytosol or insulin release. The results establish the role of the acetoacetate pathway in insulin secretion.
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Affiliation(s)
- Mahmoud El Azzouny
- Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Melissa J Longacre
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, United States
| | - Israr-Ul H Ansari
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, United States
| | - Robert T Kennedy
- Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Charles F Burant
- Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Michael J MacDonald
- Childrens Diabetes Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, United States.
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50
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Wernisch S, Pennathur S. Evaluation of coverage, retention patterns, and selectivity of seven liquid chromatographic methods for metabolomics. Anal Bioanal Chem 2016; 408:6079-91. [PMID: 27370688 DOI: 10.1007/s00216-016-9716-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/27/2016] [Accepted: 06/13/2016] [Indexed: 12/25/2022]
Abstract
Liquid chromatography-mass spectrometry-based metabolomics studies require highly selective and efficient chromatographic techniques. Typically employed reversed-phase (RP) methods fail to target polar metabolites, but the introduction of hydrophilic interaction liquid chromatography (HILIC) is slow due to perceived issues of reproducibility and ruggedness and a limited understanding of the complex retention mechanisms. In this study, we present a comparison of the chromatographic performance of a traditional RP-C18 column with zwitterionic, amide-, alkyl diol-, and aminoalkyl-based HILIC and mixed-mode columns. Our metabolite library represents one of the largest analyte sets available and consists of 764 authentic metabolite standards, including amino acids, nucleotides, sugars, and other metabolites, representing all major biological pathways and commonly observed exogenous metabolites (drugs). The coverage, retention patterns, and selectivity of the individual methods are highly diverse even between conceptually related HILIC methods. Furthermore, we show that HILIC sorbents having highly orthogonal selectivity and specificity enhance the coverage of major metabolite groups in (semi-) targeted applications compared to RP. Finally, we discuss issues encountered in the analysis of biological samples based on the results obtained with human plasma extracts. Our results demonstrate that fast and highly reproducible separations on zwitterionic columns are feasible, but knowledge of analyte properties is essential to avoid chromatographic bias and exclusion of key analytes in metabolomics studies. Graphical Abstract The chromatographic parameters of 764 authentic metabolite standards provide the basis for a comparison of coverage, selectivity and orthogonality of 7 reversed-phase (RP), mixed-mode (MM) and hydrophilic interaction liquid chromatography (HILIC) methods.
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Affiliation(s)
- Stefanie Wernisch
- Division of Nephrology, Department of Internal Medicine, University of Michigan, 5309 Brehm Center, 1000 Wall St., Ann Arbor, MI, 48105, USA
| | - Subramaniam Pennathur
- Division of Nephrology, Department of Internal Medicine, University of Michigan, 5309 Brehm Center, 1000 Wall St., Ann Arbor, MI, 48105, USA.
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