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Veluthakal R, Esparza D, Hoolachan JM, Balakrishnan R, Ahn M, Oh E, Jayasena CS, Thurmond DC. Mitochondrial Dysfunction, Oxidative Stress, and Inter-Organ Miscommunications in T2D Progression. Int J Mol Sci 2024; 25:1504. [PMID: 38338783 PMCID: PMC10855860 DOI: 10.3390/ijms25031504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/15/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024] Open
Abstract
Type 2 diabetes (T2D) is a heterogenous disease, and conventionally, peripheral insulin resistance (IR) was thought to precede islet β-cell dysfunction, promoting progression from prediabetes to T2D. New evidence suggests that T2D-lean individuals experience early β-cell dysfunction without significant IR. Regardless of the primary event (i.e., IR vs. β-cell dysfunction) that contributes to dysglycemia, significant early-onset oxidative damage and mitochondrial dysfunction in multiple metabolic tissues may be a driver of T2D onset and progression. Oxidative stress, defined as the generation of reactive oxygen species (ROS), is mediated by hyperglycemia alone or in combination with lipids. Physiological oxidative stress promotes inter-tissue communication, while pathological oxidative stress promotes inter-tissue mis-communication, and new evidence suggests that this is mediated via extracellular vesicles (EVs), including mitochondria containing EVs. Under metabolic-related stress conditions, EV-mediated cross-talk between β-cells and skeletal muscle likely trigger mitochondrial anomalies leading to prediabetes and T2D. This article reviews the underlying molecular mechanisms in ROS-related pathogenesis of prediabetes, including mitophagy and mitochondrial dynamics due to oxidative stress. Further, this review will describe the potential of various therapeutic avenues for attenuating oxidative damage, reversing prediabetes and preventing progression to T2D.
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Affiliation(s)
- Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes & Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E. Duarte Rd, Duarte, CA 91010, USA; (D.E.); (J.M.H.); (R.B.); (M.A.); (E.O.); (C.S.J.)
| | | | | | | | | | | | | | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes & Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E. Duarte Rd, Duarte, CA 91010, USA; (D.E.); (J.M.H.); (R.B.); (M.A.); (E.O.); (C.S.J.)
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2
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Urbanczyk M, Jeyagaran A, Zbinden A, Lu CE, Marzi J, Kuhlburger L, Nahnsen S, Layland SL, Duffy G, Schenke-Layland K. Decorin improves human pancreatic β-cell function and regulates ECM expression in vitro. Matrix Biol 2023; 115:160-183. [PMID: 36592738 DOI: 10.1016/j.matbio.2022.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 01/01/2023]
Abstract
Transplantation of islets of Langerhans is a promising alternative treatment strategy in severe cases of type 1 diabetes mellitus; however, the success rate is limited by the survival rate of the cells post-transplantation. Restoration of the native pancreatic niche during transplantation potentially can help to improve cell viability and function. Here, we assessed for the first time the regulatory role of the small leucine-rich proteoglycan decorin (DCN) in insulin secretion in human β-cells, and its impact on pancreatic extracellular matrix (ECM) protein expression in vitro. In depth analyses utilizing next-generation sequencing as well as Raman microspectroscopy and Raman imaging identified pathways related to glucose metabolism to be upregulated in DCN-treated cells, including oxidative phosphorylation within the mitochondria as well as proteins and lipids of the endoplasmic reticulum. We further showed the effectiveness of DCN in a transplantation setting by treating collagen type 1-encapsulated β-cell-containing pseudo-islets with DCN. Taken together, in this study, we demonstrate the potential of DCN to improve the function of insulin-secreting β-cells while reducing the expression of ECM proteins affiliated with fibrotic capsule formation, making DCN a highly promising therapeutic agent for islet transplantation.
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Affiliation(s)
- Max Urbanczyk
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany
| | - Abiramy Jeyagaran
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Aline Zbinden
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; Department of Immunology, Leiden University Medical Center Leiden, ZA 2333, the Netherlands
| | - Chuan-En Lu
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany
| | - Julia Marzi
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany; Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University Tübingen, Tübingen, Germany
| | - Laurence Kuhlburger
- Quantitative Biology Center (QBiC), Eberhard Karls University of Tübingen, Tübingen, Germany; Biomedical Data Science, Department of Computer Science, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Sven Nahnsen
- Quantitative Biology Center (QBiC), Eberhard Karls University of Tübingen, Tübingen, Germany; Biomedical Data Science, Department of Computer Science, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Shannon L Layland
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; Department of Women's Health, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Garry Duffy
- Discipline of Anatomy and the Regenerative Medicine Institute, School of Medicine, College of Medicine Nursing and Health Sciences, National University of Ireland Galway, Ireland; Science Foundation Ireland (SFI) Centre for Research in Advanced Materials for Biomedical Engineering (AMBER), Trinity College Dublin & National University of Ireland Galway, Galway, Ireland
| | - Katja Schenke-Layland
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany; Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University Tübingen, Tübingen, Germany.
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3
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Wu Z, Berlemann LA, Bader V, Sehr DA, Dawin E, Covallero A, Meschede J, Angersbach L, Showkat C, Michaelis JB, Münch C, Rieger B, Namgaladze D, Herrera MG, Fiesel FC, Springer W, Mendes M, Stepien J, Barkovits K, Marcus K, Sickmann A, Dittmar G, Busch KB, Riedel D, Brini M, Tatzelt J, Cali T, Winklhofer KF. LUBAC assembles a ubiquitin signaling platform at mitochondria for signal amplification and transport of NF-κB to the nucleus. EMBO J 2022; 41:e112006. [PMID: 36398858 PMCID: PMC9753471 DOI: 10.15252/embj.2022112006] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 11/19/2022] Open
Abstract
Mitochondria are increasingly recognized as cellular hubs to orchestrate signaling pathways that regulate metabolism, redox homeostasis, and cell fate decisions. Recent research revealed a role of mitochondria also in innate immune signaling; however, the mechanisms of how mitochondria affect signal transduction are poorly understood. Here, we show that the NF-κB pathway activated by TNF employs mitochondria as a platform for signal amplification and shuttling of activated NF-κB to the nucleus. TNF treatment induces the recruitment of HOIP, the catalytic component of the linear ubiquitin chain assembly complex (LUBAC), and its substrate NEMO to the outer mitochondrial membrane, where M1- and K63-linked ubiquitin chains are generated. NF-κB is locally activated and transported to the nucleus by mitochondria, leading to an increase in mitochondria-nucleus contact sites in a HOIP-dependent manner. Notably, TNF-induced stabilization of the mitochondrial kinase PINK1 furthermore contributes to signal amplification by antagonizing the M1-ubiquitin-specific deubiquitinase OTULIN. Overall, our study reveals a role for mitochondria in amplifying TNF-mediated NF-κB activation, both serving as a signaling platform, as well as a transport mode for activated NF-κB to the nuclear.
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Affiliation(s)
- Zhixiao Wu
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Lena A Berlemann
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Verian Bader
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
- Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Dominik A Sehr
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Eva Dawin
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
- Leibniz‐Institut für Analytische Wissenschaften—ISAS—e.VDortmundGermany
| | | | - Jens Meschede
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Lena Angersbach
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Cathrin Showkat
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Jonas B Michaelis
- Faculty of Medicine, Institute of Biochemistry IIGoethe University FrankfurtFrankfurt am MainGermany
| | - Christian Münch
- Faculty of Medicine, Institute of Biochemistry IIGoethe University FrankfurtFrankfurt am MainGermany
| | - Bettina Rieger
- Institute for Integrative Cell Biology and Physiology, Faculty of BiologyUniversity of MünsterMünsterGermany
| | - Dmitry Namgaladze
- Institute of Biochemistry I, Faculty of MedicineGoethe‐University FrankfurtFrankfurtGermany
| | - Maria Georgina Herrera
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
| | - Fabienne C Fiesel
- Department of NeuroscienceMayo ClinicJacksonvilleFLUSA
- Neuroscience PhD ProgramMayo Clinic Graduate School of Biomedical SciencesJacksonvilleFLUSA
| | - Wolfdieter Springer
- Department of NeuroscienceMayo ClinicJacksonvilleFLUSA
- Neuroscience PhD ProgramMayo Clinic Graduate School of Biomedical SciencesJacksonvilleFLUSA
| | - Marta Mendes
- Proteomics of Cellular Signaling, Department of Infection and ImmunityLuxembourg Institute of HealthStrassenLuxembourg
| | - Jennifer Stepien
- Medizinisches Proteom‐CenterRuhr‐Universität BochumBochumGermany
- Medical Proteome Analysis, Center for Protein Diagnostics (PRODI)Ruhr‐University BochumBochumGermany
| | - Katalin Barkovits
- Medizinisches Proteom‐CenterRuhr‐Universität BochumBochumGermany
- Medical Proteome Analysis, Center for Protein Diagnostics (PRODI)Ruhr‐University BochumBochumGermany
| | - Katrin Marcus
- Medizinisches Proteom‐CenterRuhr‐Universität BochumBochumGermany
- Medical Proteome Analysis, Center for Protein Diagnostics (PRODI)Ruhr‐University BochumBochumGermany
| | - Albert Sickmann
- Leibniz‐Institut für Analytische Wissenschaften—ISAS—e.VDortmundGermany
| | - Gunnar Dittmar
- Proteomics of Cellular Signaling, Department of Infection and ImmunityLuxembourg Institute of HealthStrassenLuxembourg
- Department of Life Sciences and MedicineUniversity of LuxembourgBelvauxLuxembourg
| | - Karin B Busch
- Institute for Integrative Cell Biology and Physiology, Faculty of BiologyUniversity of MünsterMünsterGermany
| | - Dietmar Riedel
- Laboratory for Electron MicroscopyMax Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | - Marisa Brini
- Department of BiologyUniversity of PaduaPaduaItaly
- Centro Studi per la Neurodegenerazione (CESNE)University of PadovaPaduaItaly
| | - Jörg Tatzelt
- Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
- RESOLV Cluster of ExcellenceRuhr University BochumBochumGermany
| | - Tito Cali
- Department of Biomedical SciencesUniversity of PaduaPaduaItaly
- Centro Studi per la Neurodegenerazione (CESNE)University of PadovaPaduaItaly
- Padua Neuroscience Center (PNC)University of PaduaPaduaItaly
| | - Konstanze F Winklhofer
- Department Molecular Cell Biology, Institute of Biochemistry and PathobiochemistryRuhr University BochumBochumGermany
- RESOLV Cluster of ExcellenceRuhr University BochumBochumGermany
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4
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Zorov DB, Andrianova NV, Babenko VA, Zorova LD, Zorov SD, Pevzner IB, Sukhikh GT, Silachev DN. Isn't It Time for Establishing Mitochondrial Nomenclature Breaking Mitochondrial Paradigm? BIOCHEMISTRY. BIOKHIMIIA 2022; 87:1487-1497. [PMID: 36717442 DOI: 10.1134/s0006297922120069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In this work, we decided to initiate a discussion concerning heterogeneity of mitochondria, suggesting that it is time to build classification of mitochondria, like the one that exists for their progenitors, α-proteobacteria, proposing possible separation of mitochondrial strains and maybe species. We continue to adhere to the general line that mitochondria are friends and foes: on the one hand, they provide the cell and organism with the necessary energy and signaling molecules, and, on the other hand, participate in destruction of the cell and the organism. Current understanding that the activity of mitochondria is not only limited to energy production, but also that these alternative non-energetic functions are unique and irreplaceable in the cell, allowed us to speak about the strong subordination of the entire cellular metabolism to characteristic functional manifestations of mitochondria. Mitochondria are capable of producing not only ATP, but also iron-sulfur clusters, steroid hormones, heme, reactive oxygen and nitrogen species, participate in thermogenesis, regulate cell death, proliferation and differentiation, participate in detoxification, etc. They are a mandatory attribute of eukaryotic cells, and, so far, no eukaryotic cells performing a non-parasitic or non-symbiotic life style have been found that lack mitochondria. We believe that the structural-functional intracellular, intercellular, inter-organ, and interspecific diversity of mitochondria is large enough to provide grounds for creating a mitochondrial nomenclature. The arguments for this are given in this analytical work.
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Affiliation(s)
- Dmitry B Zorov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia. .,Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, Moscow, 117997, Russia
| | - Nadezda V Andrianova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Valentina A Babenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, Moscow, 117997, Russia
| | - Ljubava D Zorova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, Moscow, 117997, Russia
| | - Savva D Zorov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Irina B Pevzner
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, Moscow, 117997, Russia
| | - Gennady T Sukhikh
- Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, Moscow, 117997, Russia
| | - Denis N Silachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, Moscow, 117997, Russia
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5
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Dogra S, Das D, Maity SK, Paul A, Rawat P, Daniel PV, Das K, Mitra S, Chakrabarti P, Mondal P. Liver-Derived S100A6 Propels β-Cell Dysfunction in NAFLD. Diabetes 2022; 71:2284-2296. [PMID: 35899967 DOI: 10.2337/db22-0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is an independent predictor of systemic insulin resistance and type 2 diabetes mellitus (T2DM). However, converse correlates between excess liver fat content and β-cell function remain equivocal. Specifically, how the accumulation of liver fat consequent to the enhanced de novo lipogenesis (DNL) leads to pancreatic β-cell failure and eventually to T2DM is elusive. Here, we have identified that low-molecular-weight calcium-binding protein S100A6, or calcyclin, inhibits glucose-stimulated insulin secretion (GSIS) from β cells through activation of the receptor for the advanced glycation end products and diminution of mitochondrial respiration. Serum S100A6 level is elevated both in human patients with NAFLD and in a high-fat diet-induced mouse model of NAFLD. Although serum S100A6 levels are negatively associated with β-cell insulin secretory capacity in human patients, depletion of hepatic S100A6 improves GSIS and glycemia in mice, suggesting that S100A6 contributes to the pathophysiology of diabetes in NAFLD. Moreover, transcriptional induction of hepatic S100A6 is driven by the potent regulator of DNL, carbohydrate response element-binding protein (ChREBP), and ectopic expression of ChREBP in the liver suppresses GSIS in a S100A6-sensitive manner. Together, these data suggest elevated serum levels of S100A6 may serve as a biomarker in identifying patients with NAFLD with a heightened risk of developing β-cell dysfunction. Overall, our data implicate S100A6 as, to our knowledge, a hitherto unknown hepatokine to be activated by ChREBP and that participates in the hepato-pancreatic communication to impair insulin secretion and drive the development of T2DM in NAFLD.
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Affiliation(s)
- Surbhi Dogra
- School of Basic Sciences, Indian Institute of Technology-Mandi
| | - Debajyoti Das
- Division of Cell Biology and Physiology, Council of Scientific & Industrial Research-Indian Institute of Chemical Biology, Kolkata
| | - Sujay K Maity
- Division of Cell Biology and Physiology, Council of Scientific & Industrial Research-Indian Institute of Chemical Biology, Kolkata
| | - Avishek Paul
- Division of Cell Biology and Physiology, Council of Scientific & Industrial Research-Indian Institute of Chemical Biology, Kolkata
| | - Priya Rawat
- School of Basic Sciences, Indian Institute of Technology-Mandi
| | | | - Kausik Das
- Department of Hepatology, Institute of Post-Graduate Medical Education and Research and Seth Sukhlal Karnani Memorial Hospital, Kolkata, India
| | - Souveek Mitra
- Department of Hepatology, Institute of Post-Graduate Medical Education and Research and Seth Sukhlal Karnani Memorial Hospital, Kolkata, India
| | - Partha Chakrabarti
- Division of Cell Biology and Physiology, Council of Scientific & Industrial Research-Indian Institute of Chemical Biology, Kolkata
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6
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Tarasenko TA, Koulintchenko MV. Heterogeneity of the Mitochondrial Population in Cells of Plants and Other Organisms. Mol Biol 2022. [DOI: 10.1134/s0026893322020157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Gillette AA, DeStefanis RA, Pritzl SL, Deming DA, Skala MC. Inhibition of B-cell lymphoma 2 family proteins alters optical redox ratio, mitochondrial polarization, and cell energetics independent of cell state. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210354GR. [PMID: 35643815 PMCID: PMC9142839 DOI: 10.1117/1.jbo.27.5.056505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/09/2022] [Indexed: 05/27/2023]
Abstract
SIGNIFICANCE The optical redox ratio (ORR) [autofluorescence intensity of the reduced form of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H)/flavin adenine dinucleotide (FAD)] provides a label-free method to quantify cellular metabolism. However, it is unclear whether changes in the ORR with B-cell lymphoma 2 (Bcl-2) family protein inhibition are due to metabolic stress alone or compromised cell viability. AIM Determine whether ABT-263 (navitoclax, Bcl-2 family inhibitor) changes the ORR due to changes in mitochondrial function that are independent of changes in cell viability. APPROACH SW48 colon cancer cells were used to investigate changes in ORR, mitochondrial membrane potential, oxygen consumption rates, and cell state (cell growth, viability, proliferation, apoptosis, autophagy, and senescence) with ABT-263, TAK-228 [sapanisertib, mammalian target of rapamycin complex 1/2 (mTORC 1/2) inhibitor], and their combination at 24 h. RESULTS Changes in the ORR with Bcl-2 inhibition are driven by increases in both NAD(P)H and FAD autofluorescence, corresponding with increased basal metabolic rate and increased mitochondrial polarization. ABT-263 treatment does not change cell viability or induce autophagy but does induce a senescent phenotype. The metabolic changes seen with ABT-263 treatment are mitigated by combination with mTORC1/2 inhibition. CONCLUSIONS The ORR is sensitive to increases in mitochondrial polarization, energetic state, and cell senescence, which can change independently from cell viability.
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Affiliation(s)
- Amani A. Gillette
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Rebecca A. DeStefanis
- University of Wisconsin, McArdle Laboratory for Cancer Research, Department of Oncology, Madison, Wisconsin, United States
| | - Stephanie L. Pritzl
- University of Wisconsin, Division of Hematology, Oncology and Palliative Care, Department of Medicine, Madison, Wisconsin, United States
| | - Dustin A. Deming
- University of Wisconsin, McArdle Laboratory for Cancer Research, Department of Oncology, Madison, Wisconsin, United States
- University of Wisconsin, Division of Hematology, Oncology and Palliative Care, Department of Medicine, Madison, Wisconsin, United States
- University of Wisconsin Carbone Cancer Center, Madison, Wisconsin, United States
| | - Melissa C. Skala
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
- Morgridge Institute for Research, Madison, Wisconsin, United States
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8
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Rieger B, Arroum T, Borowski M, Villalta J, Busch KB. Mitochondrial F 1 F O ATP synthase determines the local proton motive force at cristae rims. EMBO Rep 2021; 22:e52727. [PMID: 34595823 PMCID: PMC8647149 DOI: 10.15252/embr.202152727] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 08/31/2021] [Accepted: 09/10/2021] [Indexed: 12/25/2022] Open
Abstract
The classical view of oxidative phosphorylation is that a proton motive force (PMF) generated by the respiratory chain complexes fuels ATP synthesis via ATP synthase. Yet, under glycolytic conditions, ATP synthase in its reverse mode also can contribute to the PMF. Here, we dissected these two functions of ATP synthase and the role of its inhibitory factor 1 (IF1) under different metabolic conditions. pH profiles of mitochondrial sub-compartments were recorded with high spatial resolution in live mammalian cells by positioning a pH sensor directly at ATP synthase's F1 and FO subunits, complex IV and in the matrix. Our results clearly show that ATP synthase activity substantially controls the PMF and that IF1 is essential under OXPHOS conditions to prevent reverse ATP synthase activity due to an almost negligible ΔpH. In addition, we show how this changes lateral, transmembrane, and radial pH gradients in glycolytic and respiratory cells.
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Affiliation(s)
- Bettina Rieger
- Institute of Molecular Cell BiologySchool of BiologyUniversity of MünsterMünsterGermany
| | - Tasnim Arroum
- Institute of Molecular Cell BiologySchool of BiologyUniversity of MünsterMünsterGermany
| | - Marie‐Theres Borowski
- Institute of Molecular Cell BiologySchool of BiologyUniversity of MünsterMünsterGermany
| | - Jimmy Villalta
- Institute of Molecular Cell BiologySchool of BiologyUniversity of MünsterMünsterGermany
| | - Karin B Busch
- Institute of Molecular Cell BiologySchool of BiologyUniversity of MünsterMünsterGermany
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9
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Labbé K, Mookerjee S, Le Vasseur M, Gibbs E, Lerner C, Nunnari J. The modified mitochondrial outer membrane carrier MTCH2 links mitochondrial fusion to lipogenesis. J Cell Biol 2021; 220:e202103122. [PMID: 34586346 PMCID: PMC8496048 DOI: 10.1083/jcb.202103122] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/26/2021] [Accepted: 09/01/2021] [Indexed: 01/22/2023] Open
Abstract
Mitochondrial function is integrated with cellular status through the regulation of opposing mitochondrial fusion and division events. Here we uncover a link between mitochondrial dynamics and lipid metabolism by examining the cellular role of mitochondrial carrier homologue 2 (MTCH2). MTCH2 is a modified outer mitochondrial membrane carrier protein implicated in intrinsic cell death and in the in vivo regulation of fatty acid metabolism. Our data indicate that MTCH2 is a selective effector of starvation-induced mitochondrial hyperfusion, a cytoprotective response to nutrient deprivation. We find that MTCH2 stimulates mitochondrial fusion in a manner dependent on the bioactive lipogenesis intermediate lysophosphatidic acid. We propose that MTCH2 monitors flux through the lipogenesis pathway and transmits this information to the mitochondrial fusion machinery to promote mitochondrial elongation, enhanced energy production, and cellular survival under homeostatic and starvation conditions. These findings will help resolve the roles of MTCH2 and mitochondria in tissue-specific lipid metabolism in animals.
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Affiliation(s)
- Katherine Labbé
- The Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, CA
| | - Shona Mookerjee
- Touro University California, College of Pharmacy, Vallejo, CA
- The Buck Institute for Research on Aging, Novato, CA
| | - Maxence Le Vasseur
- The Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, CA
| | - Eddy Gibbs
- The Buck Institute for Research on Aging, Novato, CA
| | - Chad Lerner
- The Buck Institute for Research on Aging, Novato, CA
| | - Jodi Nunnari
- The Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, Davis, CA
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10
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Ngo J, Osto C, Villalobos F, Shirihai OS. Mitochondrial Heterogeneity in Metabolic Diseases. BIOLOGY 2021; 10:biology10090927. [PMID: 34571805 PMCID: PMC8470264 DOI: 10.3390/biology10090927] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/03/2021] [Accepted: 09/08/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Often times mitochondria within a single cell are depicted as homogenous entities both morphologically and functionally. In normal and diseased states, mitochondria are heterogeneous and display distinct functional properties. In both cases, mitochondria exhibit differences in morphology, membrane potential, and mitochondrial calcium levels. However, the degree of heterogeneity is different during disease; or rather, heterogeneity at the physiological state stems from physically distinct mitochondrial subpopulations. Overall, mitochondrial heterogeneity is both beneficial and detrimental to the cellular system; protective in enabling cellular adaptation to biological stress or detrimental in inhibiting protective mechanisms. Abstract Mitochondria have distinct architectural features and biochemical functions consistent with cell-specific bioenergetic needs. However, as imaging and isolation techniques advance, heterogeneity amongst mitochondria has been observed to occur within the same cell. Moreover, mitochondrial heterogeneity is associated with functional differences in metabolic signaling, fuel utilization, and triglyceride synthesis. These phenotypic associations suggest that mitochondrial subpopulations and heterogeneity influence the risk of metabolic diseases. This review examines the current literature regarding mitochondrial heterogeneity in the pancreatic beta-cell and renal proximal tubules as they exist in the pathological and physiological states; specifically, pathological states of glucolipotoxicity, progression of type 2 diabetes, and kidney diseases. Emphasis will be placed on the benefits of balancing mitochondrial heterogeneity and how the disruption of balancing heterogeneity leads to impaired tissue function and disease onset.
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Affiliation(s)
- Jennifer Ngo
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Corey Osto
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Frankie Villalobos
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
| | - Orian S. Shirihai
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
- Correspondence:
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11
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Chiang S, Braidy N, Maleki S, Lal S, Richardson DR, Huang MLH. Mechanisms of impaired mitochondrial homeostasis and NAD + metabolism in a model of mitochondrial heart disease exhibiting redox active iron accumulation. Redox Biol 2021; 46:102038. [PMID: 34416478 PMCID: PMC8379503 DOI: 10.1016/j.redox.2021.102038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/22/2021] [Accepted: 06/05/2021] [Indexed: 01/18/2023] Open
Abstract
Due to the high redox activity of the mitochondrion, this organelle can suffer oxidative stress. To manage energy demands while minimizing redox stress, mitochondrial homeostasis is maintained by the dynamic processes of mitochondrial biogenesis, mitochondrial network dynamics (fusion/fission), and mitochondrial clearance by mitophagy. Friedreich's ataxia (FA) is a mitochondrial disease resulting in a fatal hypertrophic cardiomyopathy due to the deficiency of the mitochondrial protein, frataxin. Our previous studies identified defective mitochondrial iron metabolism and oxidative stress potentiating cardiac pathology in FA. However, how these factors alter mitochondrial homeostasis remains uncharacterized in FA cardiomyopathy. This investigation examined the muscle creatine kinase conditional frataxin knockout mouse, which closely mimics FA cardiomyopathy, to dissect the mechanisms of dysfunctional mitochondrial homeostasis. Dysfunction of key mitochondrial homeostatic mechanisms were elucidated in the knockout hearts relative to wild-type littermates, namely: (1) mitochondrial proliferation with condensed cristae; (2) impaired NAD+ metabolism due to perturbations in Sirt1 activity and NAD+ salvage; (3) increased mitochondrial biogenesis, fusion and fission; and (4) mitochondrial accumulation of Pink1/Parkin with increased autophagic/mitophagic flux. Immunohistochemistry of FA patients' heart confirmed significantly enhanced expression of markers of mitochondrial biogenesis, fusion/fission and autophagy. These novel findings demonstrate cardiac frataxin-deficiency results in significant changes to metabolic mechanisms critical for mitochondrial homeostasis. This mechanistic dissection provides critical insight, offering the potential for maintaining mitochondrial homeostasis in FA and potentially other cardio-degenerative diseases by implementing innovative treatments targeting mitochondrial homeostasis and NAD+ metabolism.
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Affiliation(s)
- Shannon Chiang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, NSW, 2006, Australia
| | - Nady Braidy
- Centre for Healthy Brain Ageing, University of New South Wales, NSW, 2052, Australia
| | - Sanaz Maleki
- Department of Pathology, University of Sydney, NSW, 2006, Australia
| | - Sean Lal
- School of Medical Sciences, University of Sydney, NSW, 2006, Australia; Division of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, 2050, Australia
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, NSW, 2006, Australia; Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan; Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland, Australia.
| | - Michael L-H Huang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, NSW, 2006, Australia; School of Medical Sciences, University of Sydney, NSW, 2006, Australia.
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12
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High-Throughput Image Analysis of Lipid-Droplet-Bound Mitochondria. Methods Mol Biol 2021. [PMID: 34060050 DOI: 10.1007/978-1-0716-1266-8_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Changes to mitochondrial architecture are associated with various adaptive and pathogenic processes. However, quantification of changes to mitochondrial structures is limited by the yet unmet challenge of defining the borders of each individual mitochondrion within an image. Here, we describe a novel method for segmenting primary brown adipocyte (BA) mitochondria images. We describe a granular approach to quantifying subcellular structures, particularly mitochondria in close proximity to lipid droplets: peridroplet mitochondria. In addition, we lay out a novel machine-learning-based mitochondrial segmentation method that eliminates the bias of manual mitochondrial segmentation and improves object recognition compared to conventional thresholding analyses. By applying these methods, we discovered a significant difference between cytosolic and peridroplet BA mitochondrial H2O2 production and validated the machine-learning algorithm in BA via norepinephrine-induced mitochondrial fragmentation and comparing manual analyses to the automated analysis. This approach provides a high-throughput analysis protocol to quantify ratiometric probes in subpopulations of mitochondria in adipocytes.
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13
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Tornovsky-Babeay S, Weinberg-Corem N, Ben-Haroush Schyr R, Avrahami D, Lavi J, Feleke E, Kaestner KH, Dor Y, Glaser B. Biphasic dynamics of beta cell mass in a mouse model of congenital hyperinsulinism: implications for type 2 diabetes. Diabetologia 2021; 64:1133-1143. [PMID: 33558985 PMCID: PMC8117185 DOI: 10.1007/s00125-021-05390-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/08/2020] [Indexed: 12/26/2022]
Abstract
AIMS/HYPOTHESIS Acute hyperglycaemia stimulates pancreatic beta cell proliferation in the mouse whereas chronic hyperglycaemia appears to be toxic. We hypothesise that this toxic effect is mediated by increased beta cell workload, unrelated to hyperglycaemia per se. METHODS To test this hypothesis, we developed a novel mouse model of cell-autonomous increased beta cell glycolytic flux caused by a conditional heterozygous beta cell-specific mutation that activates glucokinase (GCK), mimicking key aspects of the rare human genetic disease GCK-congenital hyperinsulinism. RESULTS In the mutant mice, we observed random and fasting hypoglycaemia (random 4.5-5.4 mmol/l and fasting 3.6 mmol/l) that persisted for 15 months. GCK activation led to increased beta cell proliferation as measured by Ki67 expression (2.7% vs 1.5%, mutant and wild-type (WT), respectively, p < 0.01) that resulted in a 62% increase in beta cell mass in young mice. However, by 8 months of age, mutant mice developed impaired glucose tolerance, which was associated with decreased absolute beta cell mass from 2.9 mg at 1.5 months to 1.8 mg at 8 months of age, with preservation of individual beta cell function. Impaired glucose tolerance was further exacerbated by a high-fat/high-sucrose diet (AUC 1796 vs 966 mmol/l × min, mutant and WT, respectively, p < 0.05). Activation of GCK was associated with an increased DNA damage response and an elevated expression of Chop, suggesting metabolic stress as a contributor to beta cell death. CONCLUSIONS/INTERPRETATION We propose that increased workload-driven biphasic beta cell dynamics contribute to decreased beta cell function observed in long-standing congenital hyperinsulinism and type 2 diabetes.
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Affiliation(s)
- Sharona Tornovsky-Babeay
- Department of Endocrinology and Metabolism, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Noa Weinberg-Corem
- Department of Developmental Biology and Cancer Research, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Rachel Ben-Haroush Schyr
- Department of Developmental Biology and Cancer Research, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Dana Avrahami
- Department of Endocrinology and Metabolism, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Developmental Biology and Cancer Research, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Judith Lavi
- Department of Endocrinology and Metabolism, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Eseye Feleke
- Department of Endocrinology and Metabolism, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Klaus H Kaestner
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Yuval Dor
- Department of Developmental Biology and Cancer Research, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
| | - Benjamin Glaser
- Department of Endocrinology and Metabolism, Hadassah Medical Center, Jerusalem, Israel.
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
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14
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Weissert V, Rieger B, Morris S, Arroum T, Psathaki OE, Zobel T, Perkins G, Busch KB. Inhibition of the mitochondrial ATPase function by IF1 changes the spatiotemporal organization of ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2021; 1862:148322. [PMID: 33065099 PMCID: PMC7718977 DOI: 10.1016/j.bbabio.2020.148322] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/11/2020] [Accepted: 09/29/2020] [Indexed: 01/20/2023]
Abstract
• Mitochondrial F1FO ATP synthase is the key enzyme for mitochondrial bioenergetics. Dimeric F1FO-ATP synthase, is preferentially located at the edges of the cristae and its oligomerization state determines mitochondrial ultrastructure. The ATP synthase inhibitor protein IF1 modulates not only ATP synthase activity but also regulates both the structure and function of mitochondria. In order to understand this in more detail, we have investigated the effect of IF1 on the spatiotemporal organization of the ATP synthase. Stable cell lines were generated that overexpressed IF1 and constitutively active IF1-H49K. The expression of IF1-H49K induced a change in the localization and mobility of the ATP synthase as analyzed by single molecule tracking and localization microscopy (TALM). In addition, the ultrastructure and function of mitochondria in cells with higher levels of active IF1 displayed a gradual alteration. In state III, cristae structures were significantly altered. The inhibition of the hydrolase activity of the F1FO-ATP synthase by IF1 together with altered inner mitochondrial membrane caused re-localization and altered mobility of the enzyme.
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Affiliation(s)
- Verena Weissert
- Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, 49076 Osnabrück, Lower Saxony, Germany
| | - Bettina Rieger
- Institute of Molecular Cell Biology, Department of Biology, University of Muenster, 48149 Muenster, Germany
| | - Silke Morris
- Institute of Molecular Cell Biology, Department of Biology, University of Muenster, 48149 Muenster, Germany
| | - Tasnim Arroum
- Institute of Molecular Cell Biology, Department of Biology, University of Muenster, 48149 Muenster, Germany
| | - Olympia Ekaterini Psathaki
- Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, 49076 Osnabrück, Lower Saxony, Germany
| | - Thomas Zobel
- Imaging Network, Cells in Motion Interfaculty Centre, University of Muenster, 48149 Muenster, Germany
| | - Guy Perkins
- National Center for Microscopy and Imaging Research, University of California, San Diego, CA, USA
| | - Karin B Busch
- Institute of Molecular Cell Biology, Department of Biology, University of Muenster, 48149 Muenster, Germany.
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15
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De Oliveira MP, Liesa M. The Role of Mitochondrial Fat Oxidation in Cancer Cell Proliferation and Survival. Cells 2020; 9:E2600. [PMID: 33291682 PMCID: PMC7761891 DOI: 10.3390/cells9122600] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/10/2020] [Accepted: 12/02/2020] [Indexed: 12/21/2022] Open
Abstract
Tumors remodel their metabolism to support anabolic processes needed for replication, as well as to survive nutrient scarcity and oxidative stress imposed by their changing environment. In most healthy tissues, the shift from anabolism to catabolism results in decreased glycolysis and elevated fatty acid oxidation (FAO). This change in the nutrient selected for oxidation is regulated by the glucose-fatty acid cycle, also known as the Randle cycle. Briefly, this cycle consists of a decrease in glycolysis caused by increased mitochondrial FAO in muscle as a result of elevated extracellular fatty acid availability. Closing the cycle, increased glycolysis in response to elevated extracellular glucose availability causes a decrease in mitochondrial FAO. This competition between glycolysis and FAO and its relationship with anabolism and catabolism is conserved in some cancers. Accordingly, decreasing glycolysis to lactate, even by diverting pyruvate to mitochondria, can stop proliferation. Moreover, colorectal cancer cells can effectively shift to FAO to survive both glucose restriction and increases in oxidative stress at the expense of decreasing anabolism. However, a subset of B-cell lymphomas and other cancers require a concurrent increase in mitochondrial FAO and glycolysis to support anabolism and proliferation, thus escaping the competing nature of the Randle cycle. How mitochondria are remodeled in these FAO-dependent lymphomas to preferably oxidize fat, while concurrently sustaining high glycolysis and increasing de novo fatty acid synthesis is unclear. Here, we review studies focusing on the role of mitochondrial FAO and mitochondrial-driven lipid synthesis in cancer proliferation and survival, specifically in colorectal cancer and lymphomas. We conclude that a specific metabolic liability of these FAO-dependent cancers could be a unique remodeling of mitochondrial function that licenses elevated FAO concurrent to high glycolysis and fatty acid synthesis. In addition, blocking this mitochondrial remodeling could selectively stop growth of tumors that shifted to mitochondrial FAO to survive oxidative stress and nutrient scarcity.
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Affiliation(s)
- Matheus Pinto De Oliveira
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Molecular Biology Institute at UCLA, Los Angeles, CA 90095, USA
| | - Marc Liesa
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Molecular Biology Institute at UCLA, Los Angeles, CA 90095, USA
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16
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Insulin Modulates the Bioenergetic and Thermogenic Capacity of Rat Brown Adipocytes In Vivo by Modulating Mitochondrial Mosaicism. Int J Mol Sci 2020; 21:ijms21239204. [PMID: 33287103 PMCID: PMC7730624 DOI: 10.3390/ijms21239204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/09/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022] Open
Abstract
The effects of insulin on the bioenergetic and thermogenic capacity of brown adipocyte mitochondria were investigated by focusing on key mitochondrial proteins. Two-month-old male Wistar rats were treated acutely or chronically with a low or high dose of insulin. Acute low insulin dose increased expression of all electron transport chain complexes and complex IV activity, whereas high dose increased complex II expression. Chronic low insulin dose decreased complex I and cyt c expression while increasing complex II and IV expression and complex IV activity. Chronic high insulin dose decreased complex II, III, cyt c, and increased complex IV expression. Uncoupling protein (UCP) 1 expression was decreased after acute high insulin but increased following chronic insulin treatment. ATP synthase expression was increased after acute and decreased after chronic insulin treatment. Only a high dose of insulin increased ATP synthase activity in acute and decreased it in chronic treatment. ATPase inhibitory factor protein expression was increased in all treated groups. Confocal microscopy showed that key mitochondrial proteins colocalize differently in different mitochondria within a single brown adipocyte, indicating mitochondrial mosaicism. These results suggest that insulin modulates the bioenergetic and thermogenic capacity of rat brown adipocytes in vivo by modulating mitochondrial mosaicism.
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17
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Pepperberg DR. Amyloid-β-Dependent Inactivation of the Mitochondrial Electron Transport Chain at Low Transmembrane Potential: An Ameliorating Process in Hypoxia-Associated Neurodegenerative Disease? J Alzheimers Dis 2020; 72:663-675. [PMID: 31640091 DOI: 10.3233/jad-190476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cerebral hypoperfusion-induced hypoxia, a condition that impairs oxygen utilization and thus ATP production by mitochondrial oxidative phosphorylation (oxphos), is thought to contribute to neural degeneration in Alzheimer's disease. However, hypoxia upregulates the generation of amyloid-β (Aβ), a group of peptides known to impair/inhibit the electron transport chain (ETC) of reactions that support oxphos in the inner mitochondrial membrane (IMM). This is a hypothesis paper that reconciles the hypoxia-induced upregulation of Aβ with Aβ's ETC-inhibiting action and, specifically, posits an oxphos-enhancing effect of this inhibition under conditions of newly developing or otherwise mild hypoxia. This effect is typically transient; that is, under conditions of prolonged or severe hypoxia, the oxphos-enhancing activity is overwhelmed by Aβ's well-known toxic actions on mitochondria and other cellular components. The hypothesis is motivated by evidence that the IMM transmembrane potential Ψm, an important determinant of ETC activity, exhibits heterogeneity, i.e., a range of values, among a given local population of mitochondria. It specifically proposes that during oxygen limitation, Aβ selectively inactivates ETC complexes in mitochondria that exhibit relatively low absolute values of Ψm, thereby suppressing oxygen binding and consumption by complex IV of the ETC in these mitochondria. This effect of Aβ on low-Ψm mitochondria is hypothesized to spare hypoxia-limited oxygen for oxphos-enabling utilization by the ETC of the remaining active, higher-Ψm local mitochondria, and thereby to increase overall ATP generated collectively by the local mitochondrial population, i.e., to ameliorate hypoxia-induced oxphos reduction. The protective action of Aβ hypothesized here may slow the early development of hypoxia-associated cellular deterioration/loss in Alzheimer's disease and perhaps other neurodegenerative diseases.
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Affiliation(s)
- David R Pepperberg
- Lions of Illinois Eye Research Institute, Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
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18
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Van Wijk R, Van Wijk EP, Pang J, Yang M, Yan Y, Han J. Integrating Ultra-Weak Photon Emission Analysis in Mitochondrial Research. Front Physiol 2020; 11:717. [PMID: 32733265 PMCID: PMC7360823 DOI: 10.3389/fphys.2020.00717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022] Open
Abstract
Once regarded solely as the energy source of the cell, nowadays mitochondria are recognized to perform multiple essential functions in addition to energy production. Since the discovery of pathogenic mitochondrial DNA defects in the 1980s, research advances have revealed an increasing number of common human diseases, which share an underlying pathogenesis involving mitochondrial dysfunction. A major factor in this dysfunction is reactive oxygen species (ROS), which influence the mitochondrial-nuclear crosstalk and the link with the epigenome, an influence that provides explanations for pathogenic mechanisms. Regarding these mechanisms, we should take into account that mitochondria produce the majority of ultra-weak photon emission (UPE), an aspect that is often ignored - this type of emission may serve as assay for ROS, thus providing new opportunities for a non-invasive diagnosis of mitochondrial dysfunction. In this article, we overviewed three relevant areas of mitochondria-related research over the period 1960-2020: (a) respiration and energy production, (b) respiration-related production of free radicals and other ROS species, and (c) ultra-weak photon emission in relation to ROS and stress. First, we have outlined how these research areas initially developed independently of each other - following that, our review aims to show their stepwise integration during later stages of development. It is suggested that a further stimulation of research on UPE may have the potential to enhance the progress of modern mitochondrial research and its integration in medicine.
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Affiliation(s)
- Roeland Van Wijk
- Meluna Research, Department of Biophotonics, Geldermalsen, Netherlands
| | | | - Jingxiang Pang
- Key Laboratory for Biotech-Drugs of National Health Commission, Shandong Medicinal Biotechnology Center, Jinan, China
- Shandong First Medical University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
| | - Meina Yang
- Key Laboratory for Biotech-Drugs of National Health Commission, Shandong Medicinal Biotechnology Center, Jinan, China
- Shandong First Medical University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
| | - Yu Yan
- Meluna Research, Department of Biophotonics, Geldermalsen, Netherlands
| | - Jinxiang Han
- Key Laboratory for Biotech-Drugs of National Health Commission, Shandong Medicinal Biotechnology Center, Jinan, China
- Shandong First Medical University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
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Assali EA, Jones AE, Veliova M, Acín-Pérez R, Taha M, Miller N, Shum M, Oliveira MF, Las G, Liesa M, Sekler I, Shirihai OS. NCLX prevents cell death during adrenergic activation of the brown adipose tissue. Nat Commun 2020; 11:3347. [PMID: 32620768 PMCID: PMC7334226 DOI: 10.1038/s41467-020-16572-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 05/06/2020] [Indexed: 01/30/2023] Open
Abstract
A sharp increase in mitochondrial Ca2+ marks the activation of brown adipose tissue (BAT) thermogenesis, yet the mechanisms preventing Ca2+ deleterious effects are poorly understood. Here, we show that adrenergic stimulation of BAT activates a PKA-dependent mitochondrial Ca2+ extrusion via the mitochondrial Na+/Ca2+ exchanger, NCLX. Adrenergic stimulation of NCLX-null brown adipocytes (BA) induces a profound mitochondrial Ca2+ overload and impaired uncoupled respiration. Core body temperature, PET imaging of glucose uptake and VO2 measurements confirm a thermogenic defect in NCLX-null mice. We show that Ca2+ overload induced by adrenergic stimulation of NCLX-null BAT, triggers the mitochondrial permeability transition pore (mPTP) opening, leading to a remarkable mitochondrial swelling and cell death. Treatment with mPTP inhibitors rescue mitochondrial function and thermogenesis in NCLX-null BAT, while calcium overload persists. Our findings identify a key pathway through which BA evade apoptosis during adrenergic stimulation of uncoupling. NCLX deletion transforms the adrenergic pathway responsible for thermogenesis activation into a death pathway.
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Affiliation(s)
- Essam A Assali
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84103, Israel
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84105, Israel
| | - Anthony E Jones
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Michaela Veliova
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Rebeca Acín-Pérez
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Mahmoud Taha
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84105, Israel
| | - Nathanael Miller
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Michaël Shum
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Marcus F Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Guy Las
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84103, Israel
| | - Marc Liesa
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84105, Israel.
| | - Orian S Shirihai
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84103, Israel.
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA.
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Mancini G, Pirruccio K, Yang X, Blüher M, Rodeheffer M, Horvath TL. Mitofusin 2 in Mature Adipocytes Controls Adiposity and Body Weight. Cell Rep 2020; 26:2849-2858.e4. [PMID: 30865877 PMCID: PMC6876693 DOI: 10.1016/j.celrep.2019.02.039] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/13/2018] [Accepted: 02/11/2019] [Indexed: 12/17/2022] Open
Abstract
We found that exposure of adult animals to caloriedense foods rapidly abolished expression of mitofusin 2 (Mfn2), a gene promoting mitochondrial fusion and mitochondrion-endoplasmic reticulum interactions, in white and brown fat. Mfn2 mRN was also robustly lower in obese human subjects compared with lean controls. Adipocyte-specific knockdown of Mfn2 in adult mice led to increased food intake, adiposity, and impaired glucose metabolism on standard chow as well as on a diet with high calorie content. The body weight and adiposity of mature adipocyte-specific Mfn2 knockout mice on a standard diet were similar to those of control mice on a high-fat diet. The transcriptional profile of the adipose tissue in adipocyte-specific Mfn2 knockout mice was consistent with adipocyte proliferation, increased lipogenesis at the tissue level, and decreased glucose utilization at the systemic level. These observations suggest a possible crucial role for mitochondrial dynamics in adipocytes in initiating systemic metabolic dysregulation. Mancini et al. find that the mitochondrial fusion protein Mfn2 is lower in adipose tissue of mice on a high-fat diet and that of obese humans and that this protein in the fat is important for systemic control of metabolism.
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Affiliation(s)
- Giacomo Mancini
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Kevin Pirruccio
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Xiaoyong Yang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Matthias Blüher
- Medical Department, University of Leipzig, 04103 Leipzig, Germany
| | - Matthew Rodeheffer
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Anatomy and Histology, University of Veterinary Medicine, Budapest 1078, Hungary.
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21
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Wolf DM, Segawa M, Shirihai OS, Liesa M. Method for live-cell super-resolution imaging of mitochondrial cristae and quantification of submitochondrial membrane potentials. Methods Cell Biol 2020; 155:545-555. [PMID: 32183976 PMCID: PMC7216778 DOI: 10.1016/bs.mcb.2019.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
The emergence of diffraction-unlimited live-cell imaging technologies has enabled the examination of mitochondrial form and function in unprecedented detail. We recently developed an approach for visualizing the inner mitochondrial membrane and determined that cristae membranes possess distinct mitochondrial membrane potentials, representing unique bioenergetic subdomains within the same organelle. Here, we outline a methodology for resolving cristae and inner boundary membranes using the LSM880 with Airyscan. Furthermore, we demonstrate how to analyze TMRE fluorescence intensity using the Nernst equation to calculate membrane potentials of individual cristae. Altogether, using these new techniques to study the electrochemical properties of the cristae can help to gain deeper insight into the still elusive nature of the mitochondrion.
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Affiliation(s)
- Dane M Wolf
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Graduate Program in Nutrition and Metabolism, Graduate Medical Sciences, Boston University School of Medicine, Boston, MA, United States
| | - Mayuko Segawa
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Orian S Shirihai
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States.
| | - Marc Liesa
- Department of Medicine, Endocrinology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, United States.
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22
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Chaudhry A, Shi R, Luciani DS. A pipeline for multidimensional confocal analysis of mitochondrial morphology, function, and dynamics in pancreatic β-cells. Am J Physiol Endocrinol Metab 2020; 318:E87-E101. [PMID: 31846372 PMCID: PMC7052579 DOI: 10.1152/ajpendo.00457.2019] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Live-cell imaging of mitochondrial function and dynamics can provide vital insights into both physiology and pathophysiology, including of metabolic diseases like type 2 diabetes. However, without super-resolution microscopy and commercial analysis software, it is challenging to accurately extract features from dense multilayered mitochondrial networks, such as those in insulin-secreting pancreatic β-cells. Motivated by this, we developed a comprehensive pipeline and associated ImageJ plugin that enables 2D/3D quantification of mitochondrial network morphology and dynamics in mouse β-cells and by extension other similarly challenging cell types. The approach is based on standard confocal microscopy and shareware, making it widely accessible. The pipeline was validated using mitochondrial photolabeling and unsupervised cluster analysis and is capable of morphological and functional analyses on a per-organelle basis, including in 4D (xyzt). Overall, this tool offers a powerful framework for multiplexed analysis of mitochondrial state/function and provides a valuable resource to accelerate mitochondrial research in health and disease.
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Affiliation(s)
- Ahsen Chaudhry
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children's Hospital Research Institute, Diabetes Research Group, Vancouver, British Columbia, Canada
| | - Rocky Shi
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children's Hospital Research Institute, Diabetes Research Group, Vancouver, British Columbia, Canada
| | - Dan S Luciani
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children's Hospital Research Institute, Diabetes Research Group, Vancouver, British Columbia, Canada
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23
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Taddeo EP, Alsabeeh N, Baghdasarian S, Wikstrom JD, Ritou E, Sereda S, Erion K, Li J, Stiles L, Abdulla M, Swanson Z, Wilhelm JJ, Bellin MD, Kibbey RG, Liesa M, Shirihai OS. Mitochondrial Proton Leak Regulated by Cyclophilin D Elevates Insulin Secretion in Islets at Nonstimulatory Glucose Levels. Diabetes 2020; 69:131-145. [PMID: 31740442 PMCID: PMC6971491 DOI: 10.2337/db19-0379] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 11/11/2019] [Indexed: 12/13/2022]
Abstract
Fasting hyperinsulinemia precedes the development of type 2 diabetes. However, it is unclear whether fasting insulin hypersecretion is a primary driver of insulin resistance or a consequence of the progressive increase in fasting glycemia induced by insulin resistance in the prediabetic state. Herein, we have discovered a mechanism that specifically regulates non-glucose-stimulated insulin secretion (NGSIS) in pancreatic islets that is activated by nonesterified free fatty acids, the major fuel used by β-cells during fasting. We show that the mitochondrial permeability transition pore regulator cyclophilin D (CypD) promotes NGSIS, but not glucose-stimulated insulin secretion, by increasing mitochondrial proton leak. Islets from prediabetic obese mice show significantly higher CypD-dependent proton leak and NGSIS compared with lean mice. Proton leak-mediated NGSIS is conserved in human islets and is stimulated by exposure to nonesterified free fatty acids at concentrations observed in obese subjects. Mechanistically, proton leak activates islet NGSIS independently of mitochondrial ATP synthesis but ultimately requires closure of the KATP channel. In summary, we have described a novel nonesterified free fatty acid-stimulated pathway that selectively drives pancreatic islet NGSIS, which may be therapeutically exploited as an alternative way to halt fasting hyperinsulinemia and the progression of type 2 diabetes.
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Affiliation(s)
- Evan P Taddeo
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Nour Alsabeeh
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Siyouneh Baghdasarian
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Jakob D Wikstrom
- Dermatology and Venereology Unit, Department of Medicine, Karolinska Institutet, and Department of Dermato-Venereology, Karolinska University Hospital, Stockholm, Sweden
| | - Eleni Ritou
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Samuel Sereda
- Endocrinology, Diabetes, Nutrition and Weight Management Section, Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Karel Erion
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Jin Li
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Linsey Stiles
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Muhamad Abdulla
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
| | - Zachary Swanson
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
| | - Joshua J Wilhelm
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
| | - Melena D Bellin
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN
| | - Richard G Kibbey
- Departments of Internal Medicine (Endocrinology) and Cellular & Molecular Physiology, Yale University, New Haven, CT
| | - Marc Liesa
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA
| | - Orian S Shirihai
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
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24
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Las G, Oliveira MF, Shirihai OS. Emerging roles of β-cell mitochondria in type-2-diabetes. Mol Aspects Med 2020; 71:100843. [PMID: 31918997 DOI: 10.1016/j.mam.2019.100843] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/23/2019] [Accepted: 12/27/2019] [Indexed: 10/25/2022]
Abstract
Type-2-Diabetes (T2D) is the most common metabolic disease in the world today. It erupts as a result of peripheral insulin resistance combined with hyperinsulinemia followed by suppression of insulin secretion from pancreatic β-cells. Mitochondria play a central role in β-cells by sensing glucose and also by mediating the suppression of insulin secretion in T2D. Here, we will summarize the evidence accumulated for the roles of β-cells mitochondria in T2D. We will present an updated view on how mitochondria in β-cells have been associated with T2D, from the genetic, bioenergetic, redox and structural points of view. The emerging picture is that mitochondrial structure and dysfunction directly contribute to β-cell function and in the pathogenesis of T2D.
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Affiliation(s)
- Guy Las
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel
| | - Marcus F Oliveira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal Do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, Brazil.
| | - Orian S Shirihai
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
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25
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Knorre DA. Intracellular quality control of mitochondrial DNA: evidence and limitations. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190176. [PMID: 31787047 DOI: 10.1098/rstb.2019.0176] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cells can harbour mitochondria with markedly different transmembrane potentials. Intracellular mitochondrial quality-control mechanisms (e.g. mitophagy) rely on this intracellular variation to distinguish functional and damaged (depolarized) mitochondria. Given that intracellular mitochondrial DNA (mtDNA) genetic variation can induce mitochondrial heterogeneity, mitophagy could remove deleterious mtDNA variants in cells. However, the reliance of mitophagy on the mitochondrial transmembrane potential suggests that mtDNAs with deleterious mutations in ATP synthase can evade the control. This evasion is possible because inhibition of ATP synthase can increase the mitochondrial transmembrane potential. Moreover, the linkage of the mtDNA genotype to individual mitochondrial performance is expected to be weak owing to intracellular mitochondrial intercomplementation. Nonetheless, I reason that intracellular mtDNA quality control is possible and crucial at the zygote stage of the life cycle. Indeed, species with biparental mtDNA inheritance or frequent 'leakage' of paternal mtDNA can be vulnerable to invasion of selfish mtDNAs at the stage of gamete fusion. Here, I critically review recent findings on intracellular mtDNA quality control by mitophagy and discuss other mechanisms by which the nuclear genome can affect the competition of mtDNA variants in the cell. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Dmitry A Knorre
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya Str. 8-2, Moscow 119991, Russia
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26
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Salewskij K, Rieger B, Hager F, Arroum T, Duwe P, Villalta J, Colgiati S, Richter CP, Psathaki OE, Enriquez JA, Dellmann T, Busch KB. The spatio-temporal organization of mitochondrial F 1F O ATP synthase in cristae depends on its activity mode. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148091. [PMID: 31669489 DOI: 10.1016/j.bbabio.2019.148091] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/02/2019] [Accepted: 10/18/2019] [Indexed: 12/11/2022]
Abstract
F1FO ATP synthase, also known as complex V, is a key enzyme of mitochondrial energy metabolism that can synthesize and hydrolyze ATP. It is not known whether the ATP synthase and ATPase function are correlated with a different spatio-temporal organisation of the enzyme. In order to analyze this, we tracked and localized single ATP synthase molecules in situ using live cell microscopy. Under normal conditions, complex V was mainly restricted to cristae indicated by orthogonal trajectories along the cristae membranes. In addition confined trajectories that are quasi immobile exist. By inhibiting glycolysis with 2-DG, the activity and mobility of complex V was altered. The distinct cristae-related orthogonal trajectories of complex V were obliterated. Moreover, a mobile subpopulation of complex V was found in the inner boundary membrane. The observed changes in the ratio of dimeric/monomeric complex V, respectively less mobile/more mobile complex V and its activity changes were reversible. In IF1-KO cells, in which ATP hydrolysis is not inhibited by IF1, complex V was more mobile, while inhibition of ATP hydrolysis by BMS-199264 reduced the mobility of complex V. Taken together, these data support the existence of different subpopulations of complex V, ATP synthase and ATP hydrolase, the latter with higher mobility and probably not prevailing at the cristae edges. Obviously, complex V reacts quickly and reversibly to metabolic conditions, not only by functional, but also by spatial and structural reorganization.
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Affiliation(s)
- Kirill Salewskij
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany
| | - Bettina Rieger
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany
| | - Frances Hager
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany
| | - Tasnim Arroum
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany
| | - Patrick Duwe
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany
| | - Jimmy Villalta
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany
| | - Sara Colgiati
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Catania, Spain; Institute of Nutrition and Food Technology, Biomedical Research Centre, Department of Physiology, University of Granada, Granada, Andalusia, Spain
| | - Christian P Richter
- University of Osnabrück, School of Biology, University of Osnabrück, 49076 Osnabrück, Lower Saxony, Germany; Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, 49076 Osnabrück, Lower Saxony, Germany
| | - Olympia E Psathaki
- University of Osnabrück, School of Biology, University of Osnabrück, 49076 Osnabrück, Lower Saxony, Germany; Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, 49076 Osnabrück, Lower Saxony, Germany
| | - José A Enriquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Catania, Spain
| | - Timo Dellmann
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany
| | - Karin B Busch
- University Münster, Department of Biology, Institute of Molecular Cell Biology, 48149 Münster, North Rhine-Westphalia, Germany.
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27
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Wolf DM, Segawa M, Kondadi AK, Anand R, Bailey ST, Reichert AS, van der Bliek AM, Shackelford DB, Liesa M, Shirihai OS. Individual cristae within the same mitochondrion display different membrane potentials and are functionally independent. EMBO J 2019; 38:e101056. [PMID: 31609012 PMCID: PMC6856616 DOI: 10.15252/embj.2018101056] [Citation(s) in RCA: 206] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 08/12/2019] [Accepted: 09/05/2019] [Indexed: 11/17/2022] Open
Abstract
The mitochondrial membrane potential (ΔΨm ) is the main driver of oxidative phosphorylation (OXPHOS). The inner mitochondrial membrane (IMM), consisting of cristae and inner boundary membranes (IBM), is considered to carry a uniform ΔΨm . However, sequestration of OXPHOS components in cristae membranes necessitates a re-examination of the equipotential representation of the IMM. We developed an approach to monitor ΔΨm at the resolution of individual cristae. We found that the IMM was divided into segments with distinct ΔΨm , corresponding to cristae and IBM. ΔΨm was higher at cristae compared to IBM. Treatment with oligomycin increased, whereas FCCP decreased, ΔΨm heterogeneity along the IMM. Impairment of cristae structure through deletion of MICOS-complex components or Opa1 diminished this intramitochondrial heterogeneity of ΔΨm . Lastly, we determined that different cristae within the individual mitochondrion can have disparate membrane potentials and that interventions causing acute depolarization may affect some cristae while sparing others. Altogether, our data support a new model in which cristae within the same mitochondrion behave as independent bioenergetic units, preventing the failure of specific cristae from spreading dysfunction to the rest.
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Affiliation(s)
- Dane M Wolf
- Department of Medicine (Endocrinology)Department of Molecular and Medical PharmacologyDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
- Graduate Program in Nutrition and MetabolismGraduate Medical SciencesBoston University School of MedicineBostonMAUSA
| | - Mayuko Segawa
- Department of Medicine (Endocrinology)Department of Molecular and Medical PharmacologyDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
| | - Arun Kumar Kondadi
- Institute of Biochemistry and Molecular Biology IMedical FacultyHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Ruchika Anand
- Institute of Biochemistry and Molecular Biology IMedical FacultyHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Sean T Bailey
- Department of Pulmonary and Critical Care MedicineDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
- Jonsson Comprehensive Cancer CenterDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
- Lineberger Comprehensive Cancer CenterUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Andreas S Reichert
- Institute of Biochemistry and Molecular Biology IMedical FacultyHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Alexander M van der Bliek
- Molecular Biology Institute at UCLALos AngelesCAUSA
- Department of Biological ChemistryDavid Geffen School of Medicine at UCLALos AngelesCAUSA
| | - David B Shackelford
- Department of Pulmonary and Critical Care MedicineDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
- Jonsson Comprehensive Cancer CenterDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
| | - Marc Liesa
- Department of Medicine (Endocrinology)Department of Molecular and Medical PharmacologyDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
- Molecular Biology Institute at UCLALos AngelesCAUSA
| | - Orian S Shirihai
- Department of Medicine (Endocrinology)Department of Molecular and Medical PharmacologyDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
- Graduate Program in Nutrition and MetabolismGraduate Medical SciencesBoston University School of MedicineBostonMAUSA
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28
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The Role of Mitochondria in the Mechanisms of Cardiac Ischemia-Reperfusion Injury. Antioxidants (Basel) 2019; 8:antiox8100454. [PMID: 31590423 PMCID: PMC6826663 DOI: 10.3390/antiox8100454] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 01/11/2023] Open
Abstract
Mitochondria play a critical role in maintaining cellular function by ATP production. They are also a source of reactive oxygen species (ROS) and proapoptotic factors. The role of mitochondria has been established in many aspects of cell physiology/pathophysiology, including cell signaling. Mitochondria may deteriorate under various pathological conditions, including ischemia-reperfusion (IR) injury. Mitochondrial injury can be one of the main causes for cardiac and other tissue injuries by energy stress and overproduction of toxic reactive oxygen species, leading to oxidative stress, elevated calcium and apoptotic and necrotic cell death. However, the interplay among these processes in normal and pathological conditions is still poorly understood. Mitochondria play a critical role in cardiac IR injury, where they are directly involved in several pathophysiological mechanisms. We also discuss the role of mitochondria in the context of mitochondrial dynamics, specializations and heterogeneity. Also, we wanted to stress the existence of morphologically and functionally different mitochondrial subpopulations in the heart that may have different sensitivities to diseases and IR injury. Therefore, various cardioprotective interventions that modulate mitochondrial stability, dynamics and turnover, including various pharmacologic agents, specific mitochondrial antioxidants and uncouplers, and ischemic preconditioning can be considered as the main strategies to protect mitochondrial and cardiovascular function and thus enhance longevity.
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29
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Morten KJ, Potter M, Badder L, Sivathondan P, Dragovic R, Neumann A, Gavin J, Shrestha R, Reilly S, Phadwal K, Lodge TA, Borzychowski A, Cookson S, Mitchell C, Morovat A, Simon AK, Uusimaa J, Hynes J, Poulton J. Insights into pancreatic β cell energy metabolism using rodent β cell models. Wellcome Open Res 2019; 2:14. [PMID: 31754635 PMCID: PMC6854877 DOI: 10.12688/wellcomeopenres.10535.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2019] [Indexed: 01/07/2023] Open
Abstract
Background: Mitochondrial diabetes is primarily caused by β-cell failure, a cell type whose unique properties are important in pathogenesis. Methods: By reducing glucose, we induced energetic stress in two rodent β-cell models to assess effects on cellular function. Results: Culturing rat insulin-secreting INS-1 cells in low glucose conditions caused a rapid reduction in whole cell respiration, associated with elevated mitochondrial reactive oxygen species production, and an altered glucose-stimulated insulin secretion profile. Prolonged exposure to reduced glucose directly impaired mitochondrial function and reduced autophagy. Conclusions: Insulinoma cell lines have a very different bioenergetic profile to many other cell lines and provide a useful model of mechanisms affecting β-cell mitochondrial function.
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Affiliation(s)
- Karl J Morten
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Michelle Potter
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Luned Badder
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Pamela Sivathondan
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Rebecca Dragovic
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Abigale Neumann
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - James Gavin
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Roshan Shrestha
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Svetlana Reilly
- Department of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, UK
| | - Kanchan Phadwal
- BRC Translational Immunology Lab, NIHR, Nuffield Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Tiffany A Lodge
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Angela Borzychowski
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Sharon Cookson
- Institute of Cellular Medicine, Haematological Sciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Corey Mitchell
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | | | | | - Johanna Uusimaa
- Department of Paediatrics, University of Oulu, Oulu, Finland
| | - James Hynes
- Luxcel BioSciences Ltd, BioInnovation Centre, University College Cork, Cork, Ireland
| | - Joanna Poulton
- Nuffield Department of Obstetrics & Gynaecology, The Women's Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
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30
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Assali EA, Shlomo D, Zeng J, Taddeo EP, Trudeau KM, Erion KA, Colby AH, Grinstaff MW, Liesa M, Las G, Shirihai OS. Nanoparticle-mediated lysosomal reacidification restores mitochondrial turnover and function in β cells under lipotoxicity. FASEB J 2019; 33:4154-4165. [PMID: 30550357 PMCID: PMC8793810 DOI: 10.1096/fj.201801292r] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 11/12/2018] [Indexed: 11/11/2022]
Abstract
Chronic exposure of pancreatic β cells to high concentrations of free fatty acids leads to lipotoxicity (LT)-mediated suppression of glucose-stimulated insulin secretion. This effect is in part caused by a decline in mitochondrial function as well as by a reduction in lysosomal acidification. Because both mitochondria and lysosomes can alter one another's function, it remains unclear which initiating dysfunction sets off the detrimental cascade of LT, ultimately leading to β-cell failure. Here, we investigated the effects of restoring lysosomal acidity on mitochondrial function under LT. Our results show that LT induces a dose-dependent lysosomal alkalization accompanied by an increase in mitochondrial mass. This increase is due to a reduction in mitochondrial turnover as analyzed by MitoTimer, a fluorescent protein for which the emission is regulated by mitochondrial clearance rate. Mitochondrial oxygen consumption rate, citrate synthase activity, and ATP content are all reduced by LT. Restoration of lysosomal acidity using lysosome-targeted nanoparticles is accompanied by stimulation of mitochondrial turnover as revealed by mitophagy measurements and the recovery of mitochondrial mass. Remarkably, re-acidification restores citrate synthase activity and ATP content in an insulin secreting β-cell line (INS-1). Furthermore, nanoparticle-mediated lysosomal reacidification rescues mitochondrial maximal respiratory capacity in both INS-1 cells and primary mouse islets. Therefore, our results indicate that mitochondrial dysfunction is downstream of lysosomal alkalization under lipotoxic conditions and that recovery of lysosomal acidity is sufficient to restore the bioenergetic defects.-Assali, E. A., Shlomo, D., Zeng, J., Taddeo, E. P., Trudeau, K. M., Erion, K. A., Colby, A. H., Grinstaff, M. W., Liesa, M., Las, G., Shirihai, O. S. Nanoparticle-mediated lysosomal reacidification restores mitochondrial turnover and function in β cells under lipotoxicity.
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Affiliation(s)
- Essam A. Assali
- Department of Clinical BiochemistryFaculty of Health SciencesBen Gurion UniversityBeer-ShevaIsrael
- Division of EndocrinologyDepartment of MedicineUniversity of CaliforniaLos AngelesLos AngelesCaliforniaUSA
| | - Dovi Shlomo
- Department of Clinical BiochemistryFaculty of Health SciencesBen Gurion UniversityBeer-ShevaIsrael
| | - Jialiu Zeng
- Department of Biomedical EngineeringBoston UniversityBostonMassachusettsUSA
- Department of ChemistryBoston UniversityBostonMassachusettsUSA
- Department of MedicineBoston UniversityBostonMassachusettsUSA
| | - Evan P. Taddeo
- Division of EndocrinologyDepartment of MedicineUniversity of CaliforniaLos AngelesLos AngelesCaliforniaUSA
| | - Kyle M. Trudeau
- Obesity and Nutrition SectionDepartment of MedicineEvans Biomedical Research CenterBoston University School of MedicineBostonMassachusettsUSA
| | - Karel A. Erion
- Division of EndocrinologyDepartment of MedicineUniversity of CaliforniaLos AngelesLos AngelesCaliforniaUSA
| | - Aaron H. Colby
- Department of Biomedical EngineeringBoston UniversityBostonMassachusettsUSA
| | - Mark W. Grinstaff
- Department of Biomedical EngineeringBoston UniversityBostonMassachusettsUSA
- Department of ChemistryBoston UniversityBostonMassachusettsUSA
- Department of MedicineBoston UniversityBostonMassachusettsUSA
| | - Marc Liesa
- Division of EndocrinologyDepartment of MedicineUniversity of CaliforniaLos AngelesLos AngelesCaliforniaUSA
- Department of Molecular and Medical PharmacologyDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesLos AngelesCaliforniaUSA
- Molecular Biology InstituteUniversity of CaliforniaLos AngelesLos AngelesCaliforniaUSA
| | - Guy Las
- Department of Clinical BiochemistryFaculty of Health SciencesBen Gurion UniversityBeer-ShevaIsrael
| | - Orian S. Shirihai
- Department of Clinical BiochemistryFaculty of Health SciencesBen Gurion UniversityBeer-ShevaIsrael
- Division of EndocrinologyDepartment of MedicineUniversity of CaliforniaLos AngelesLos AngelesCaliforniaUSA
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Petcherski A, Trudeau KM, Wolf DM, Segawa M, Lee J, Taddeo EP, Deeney JT, Liesa M. Elamipretide Promotes Mitophagosome Formation and Prevents Its Reduction Induced by Nutrient Excess in INS1 β-cells. J Mol Biol 2018; 430:4823-4833. [PMID: 30389435 DOI: 10.1016/j.jmb.2018.10.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/22/2018] [Accepted: 10/24/2018] [Indexed: 11/28/2022]
Abstract
Elamipretide is a tetrapeptide that restores defects in mitochondrial function, binds to cardiolipin, and is being tested in clinical trials for mitochondria-related diseases. However, whether elamipretide modulates mitochondrial quality control and dynamics, processes essential to preserve mitochondrial function, is unclear. Thus, we tested the effects of elamipretide on mitochondrial morphology, mitophagosome formation, and their early disruption induced by excess nutrients in INS1 β-cells. Elamipretide treatment was sufficient to increase engulfment of mitochondria into autophagosomes in control INS1 β-cells, without inducing widespread changes in mitochondrial morphology or membrane potential. In an early pathogenic context mimicked by short-term exposure to nutrient excess, elamipretide treatment prevented both mitochondrial fragmentation and defects in the engulfment of mitochondria into autophagosomes. On the other hand, elamipretide did not prevent lysosomal defects induced by nutrient excess. Accordingly, elamipretide treatment did not entail benefits on pathogenic p62 and LC3II accumulation or on insulin secretory function. In conclusion, our data show that elamipretide selectively stimulates the engulfment of mitochondria into autophagosomes and prevents its defects induced by nutrient excess. Thus, we propose that improved selectivity of mitochondrial quality control processes might contribute to the benefits stemming from elamipretide treatments in other disease models.
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Affiliation(s)
- Anton Petcherski
- Departments of Medicine, Endocrinology and Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Kyle M Trudeau
- Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Dane M Wolf
- Departments of Medicine, Endocrinology and Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Mayuko Segawa
- Departments of Medicine, Endocrinology and Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Jennifer Lee
- Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Evan P Taddeo
- Departments of Medicine, Endocrinology and Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Jude T Deeney
- Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Marc Liesa
- Departments of Medicine, Endocrinology and Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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32
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Taddeo EP, Stiles L, Sereda S, Ritou E, Wolf DM, Abdullah M, Swanson Z, Wilhelm J, Bellin M, McDonald P, Caradonna K, Neilson A, Liesa M, Shirihai OS. Individual islet respirometry reveals functional diversity within the islet population of mice and human donors. Mol Metab 2018; 16:150-159. [PMID: 30098928 PMCID: PMC6157638 DOI: 10.1016/j.molmet.2018.07.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/25/2018] [Accepted: 07/01/2018] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Islets from the same pancreas show remarkable variability in glucose sensitivity. While mitochondrial respiration is essential for glucose-stimulated insulin secretion, little is known regarding heterogeneity in mitochondrial function at the individual islet level. This is due in part to a lack of high-throughput and non-invasive methods for detecting single islet function. METHODS We have developed a novel non-invasive, high-throughput methodology capable of assessing mitochondrial respiration in large-sized individual islets using the XF96 analyzer (Agilent Technologies). RESULTS By increasing measurement sensitivity, we have reduced the minimal size of mouse and human islets needed to assess mitochondrial respiration to single large islets of >35,000 μm2 area (∼210 μm diameter). In addition, we have measured heterogeneous glucose-stimulated mitochondrial respiration among individual human and mouse islets from the same pancreas, allowing population analyses of islet mitochondrial function for the first time. CONCLUSIONS We have developed a novel methodology capable of analyzing mitochondrial function in large-sized individual islets. By highlighting islet functional heterogeneity, we hope this methodology can significantly advance islet research.
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Affiliation(s)
- Evan P Taddeo
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Linsey Stiles
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Samuel Sereda
- Department of Medicine, Endocrinology, Diabetes, Nutrition and Weight Management Section, Boston University School of Medicine, 650 Albany St., Room 840, Boston, MA 02118, USA
| | - Eleni Ritou
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Dane M Wolf
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA
| | - Muhamad Abdullah
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Zachary Swanson
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Josh Wilhelm
- Department of Surgery and Schulze Diabetes Institute, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Melena Bellin
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | - Patrick McDonald
- Center for Health Research Innovation, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | | | | | - Marc Liesa
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA.
| | - Orian S Shirihai
- Department of Medicine, Division of Endocrinology, Diabetes and Hypertension, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Center for Health Sciences, 650 Charles E. Young St., Los Angeles, CA 90095, USA; Department of Medicine, Endocrinology, Diabetes, Nutrition and Weight Management Section, Boston University School of Medicine, 650 Albany St., Room 840, Boston, MA 02118, USA.
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33
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Fex M, Nicholas LM, Vishnu N, Medina A, Sharoyko VV, Nicholls DG, Spégel P, Mulder H. The pathogenetic role of β-cell mitochondria in type 2 diabetes. J Endocrinol 2018; 236:R145-R159. [PMID: 29431147 DOI: 10.1530/joe-17-0367] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 01/15/2018] [Indexed: 12/17/2022]
Abstract
Mitochondrial metabolism is a major determinant of insulin secretion from pancreatic β-cells. Type 2 diabetes evolves when β-cells fail to release appropriate amounts of insulin in response to glucose. This results in hyperglycemia and metabolic dysregulation. Evidence has recently been mounting that mitochondrial dysfunction plays an important role in these processes. Monogenic dysfunction of mitochondria is a rare condition but causes a type 2 diabetes-like syndrome owing to β-cell failure. Here, we describe novel advances in research on mitochondrial dysfunction in the β-cell in type 2 diabetes, with a focus on human studies. Relevant studies in animal and cell models of the disease are described. Transcriptional and translational regulation in mitochondria are particularly emphasized. The role of metabolic enzymes and pathways and their impact on β-cell function in type 2 diabetes pathophysiology are discussed. The role of genetic variation in mitochondrial function leading to type 2 diabetes is highlighted. We argue that alterations in mitochondria may be a culprit in the pathogenetic processes culminating in type 2 diabetes.
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Affiliation(s)
- Malin Fex
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Lisa M Nicholas
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Neelanjan Vishnu
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Anya Medina
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Vladimir V Sharoyko
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - David G Nicholls
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Peter Spégel
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
- Department of ChemistryCenter for Analysis and Synthesis, Lund University, Sweden
| | - Hindrik Mulder
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
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34
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Morten KJ, Potter M, Badder L, Sivathondan P, Dragovic R, Neumann A, Gavin J, Shrestha R, Reilly S, Phadwal K, Lodge TA, Borzychowski A, Cookson S, Mitchell C, Morovat A, Simon AK, Uusimaa J, Hynes J, Poulton J. Insights into pancreatic β cell energy metabolism using rodent β cell models. Wellcome Open Res 2017; 2:14. [DOI: 10.12688/wellcomeopenres.10535.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2019] [Indexed: 11/20/2022] Open
Abstract
Background: Mitochondrial diabetes is primarily caused by β-cell failure, a cell type whose unique properties are important in pathogenesis. Methods: By reducing glucose, we induced energetic stress in two rodent β-cell models to assess effects on cellular function. Results: Culturing rat insulin-secreting INS-1 cells in low glucose conditions caused a rapid reduction in whole cell respiration, associated with elevated mitochondrial reactive oxygen species production, and an altered glucose-stimulated insulin secretion profile. Prolonged exposure to reduced glucose directly impaired mitochondrial function and reduced autophagy. Conclusions: Insulinoma cell lines have a very different bioenergetic profile to many other cell lines and provide a useful model of mechanisms affecting β-cell mitochondrial function.
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35
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Tien T, Zhang J, Muto T, Kim D, Sarthy VP, Roy S. High Glucose Induces Mitochondrial Dysfunction in Retinal Müller Cells: Implications for Diabetic Retinopathy. Invest Ophthalmol Vis Sci 2017; 58:2915-2921. [PMID: 28586916 PMCID: PMC5460955 DOI: 10.1167/iovs.16-21355] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purpose To investigate whether high glucose (HG) induces mitochondrial dysfunction and promotes apoptosis in retinal Müller cells. Methods Rat retinal Müller cells (rMC-1) grown in normal (N) or HG (30 mM glucose) medium for 7 days were subjected to MitoTracker Red staining to identify the mitochondrial network. Digital images of mitochondria were captured in live cells under confocal microscopy and analyzed for mitochondrial morphology changes based on form factor (FF) and aspect ratio (AR) values. Mitochondrial metabolic function was assessed by measuring oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) using a bioenergetic analyzer. Cells undergoing apoptosis were identified by differential dye staining and TUNEL assay, and cytochrome c levels were assessed by Western blot analysis. Results Cells grown in HG exhibited significantly increased mitochondrial fragmentation compared to those grown in N medium (FF = 1.7 ± 0.1 vs. 2.3 ± 0.1; AR = 2.1 ± 0.1 vs. 2.5 ± 0.2; P < 0.01). OCR and ECAR were significantly reduced in cells grown in HG medium compared to those grown in N medium (steady state: 75% ± 20% of control, P < 0.02; 64% ± 22% of control, P < 0.02, respectively). These cells also exhibited a significant increase (∼2-fold) in the number of apoptotic cells compared to those grown in N medium (P < 0.01), with a concomitant increase in cytochrome c levels (247% ± 94% of control, P < 0.05). Conclusions Findings indicate that HG-induced mitochondrial morphology changes and subsequent mitochondrial dysfunction may contribute to retinal Müller cell loss associated with diabetic retinopathy.
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Affiliation(s)
- Thomas Tien
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Joyce Zhang
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Tetsuya Muto
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Dongjoon Kim
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Vijay P Sarthy
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Sayon Roy
- Departments of Medicine and Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
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36
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Abstract
The pancreatic β-cell secretes insulin in response to elevated plasma glucose. This review applies an external bioenergetic critique to the central processes of glucose-stimulated insulin secretion, including glycolytic and mitochondrial metabolism, the cytosolic adenine nucleotide pool, and its interaction with plasma membrane ion channels. The control mechanisms responsible for the unique responsiveness of the cell to glucose availability are discussed from bioenergetic and metabolic control standpoints. The concept of coupling factor facilitation of secretion is critiqued, and an attempt is made to unravel the bioenergetic basis of the oscillatory mechanisms controlling secretion. The need to consider the physiological constraints operating in the intact cell is emphasized throughout. The aim is to provide a coherent pathway through an extensive, complex, and sometimes bewildering literature, particularly for those unfamiliar with the field.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Research on Aging, Novato, California; and Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmo, Sweden
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37
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Morten KJ, Potter M, Badder L, Sivathondan P, Dragovic R, Neumann A, Gavin J, Shrestha R, Reilly S, Phadwal K, Lodge TA, Borzychowski A, Cookson S, Mitchell C, Morovat A, Simon AK, Uusimaa J, Hynes J, Poulton J. Insights into pancreatic β cell energy metabolism using rodent β cell models. Wellcome Open Res 2017; 2:14. [DOI: 10.12688/wellcomeopenres.10535.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2017] [Indexed: 11/20/2022] Open
Abstract
Background:Mitochondrial diabetes is primarily caused by β-cell failure, but there are gaps in our understanding of pathogenesis.Methods:By reducing glucose, we induced energetic stress in two rodent β-cell models to assess effects on cellular function.Results:Culturing rat insulin-secreting INS-1 cells in low glucose conditions caused a rapid reduction in whole cell respiration, associated with elevated mitochondrial reactive oxygen species production, and an altered glucose-stimulated insulin secretion profile. Prolonged exposure to reduced glucose directly impaired mitochondrial function and reduced autophagy.Conclusions:Insulinoma cell lines provide a useful model of mechanisms affecting β-cell mitochondrial function or studying mitochondrial associated drug toxicity.
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38
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Roscioni SS, Migliorini A, Gegg M, Lickert H. Impact of islet architecture on β-cell heterogeneity, plasticity and function. Nat Rev Endocrinol 2016; 12:695-709. [PMID: 27585958 DOI: 10.1038/nrendo.2016.147] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although β-cell heterogeneity was discovered more than 50 years ago, the underlying principles have been explored only during the past decade. Islet-cell heterogeneity arises during pancreatic development and might reflect the existence of distinct populations of progenitor cells and the developmental pathways of endocrine cells. Heterogeneity can also be acquired in the postnatal period owing to β-cell plasticity or changes in islet architecture. Furthermore, β-cell neogenesis, replication and dedifferentiation represent alternative sources of β-cell heterogeneity. In addition to a physiological role, β-cell heterogeneity influences the development of diabetes mellitus and its response to treatment. Identifying phenotypic and functional markers to discriminate distinct β-cell subpopulations and the mechanisms underpinning their regulation is warranted to advance current knowledge of β-cell function and to design novel regenerative strategies that target subpopulations of β cells. In this context, the Wnt/planar cell polarity (PCP) effector molecule Flattop can distinguish two unique β-cell subpopulations with specific transcriptional signatures, functional properties and differential responses to environmental stimuli. In vivo targeting of these β-cell subpopulations might, therefore, represent an alternative strategy for the future treatment of diabetes mellitus.
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Affiliation(s)
- Sara S Roscioni
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
- German Center for Diabetes Research, 85764 Neuherberg, Germany
| | - Adriana Migliorini
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
- German Center for Diabetes Research, 85764 Neuherberg, Germany
| | - Moritz Gegg
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
- Technische Universität München, 81675 München, Germany
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39
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Trudeau KM, Colby AH, Zeng J, Las G, Feng JH, Grinstaff MW, Shirihai OS. Lysosome acidification by photoactivated nanoparticles restores autophagy under lipotoxicity. J Cell Biol 2016; 214:25-34. [PMID: 27377248 PMCID: PMC4932370 DOI: 10.1083/jcb.201511042] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 06/15/2016] [Indexed: 12/11/2022] Open
Abstract
In pancreatic β-cells, liver hepatocytes, and cardiomyocytes, chronic exposure to high levels of fatty acids (lipotoxicity) inhibits autophagic flux and concomitantly decreases lysosomal acidity. Whether impaired lysosomal acidification is causally inhibiting autophagic flux and cellular functions could not, up to the present, be determined because of the lack of an approach to modify lysosomal acidity. To address this question, lysosome-localizing nanoparticles are described that, upon UV photoactivation, enable controlled acidification of impaired lysosomes. The photoactivatable, acidifying nanoparticles (paNPs) demonstrate lysosomal uptake in INS1 and mouse β-cells. Photoactivation of paNPs in fatty acid-treated INS1 cells enhances lysosomal acidity and function while decreasing p62 and LC3-II levels, indicating rescue of autophagic flux upon acute lysosomal acidification. Furthermore, paNPs improve glucose-stimulated insulin secretion that is reduced under lipotoxicity in INS1 cells and mouse islets. These results establish a causative role for impaired lysosomal acidification in the deregulation of autophagy and β-cell function under lipotoxicity.
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Affiliation(s)
- Kyle M Trudeau
- Obesity and Nutrition Section, Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118
| | - Aaron H Colby
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215 Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215
| | - Jialiu Zeng
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215
| | - Guy Las
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103, Israel
| | - Jiazuo H Feng
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215
| | - Mark W Grinstaff
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215
| | - Orian S Shirihai
- Obesity and Nutrition Section, Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118 Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103, Israel Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90045
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40
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Reinhardt F, Schultz J, Waterstradt R, Baltrusch S. Drp1 guarding of the mitochondrial network is important for glucose-stimulated insulin secretion in pancreatic beta cells. Biochem Biophys Res Commun 2016; 474:646-651. [PMID: 27154223 DOI: 10.1016/j.bbrc.2016.04.142] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
Abstract
Mitochondria form a tubular network in mammalian cells, and the mitochondrial life cycle is determined by fission, fusion and autophagy. Dynamin-related protein 1 (Drp1) has a pivotal role in these processes because it alone is able to constrict mitochondria. However, the regulation and function of Drp1 have been shown to vary between cell types. Mitochondrial morphology affects mitochondrial metabolism and function. In pancreatic beta cells mitochondrial metabolism is a key component of the glucose-induced cascade of insulin secretion. The goal of the present study was to investigate the action of Drp1 in pancreatic beta cells. For this purpose Drp1 was down-regulated by means of shDrp1 in insulin-secreting INS1 cells and mouse pancreatic islets. In INS1 cells reduced Drp1 expression resulted in diminished expression of proteins regulating mitochondrial fusion, namely mitofusin 1 and 2, and optic atrophy protein 1. Diminished mitochondrial dynamics can therefore be assumed. After down-regulation of Drp1 in INS1 cells and spread mouse islets the initially homogenous mitochondrial network characterised by a moderate level of interconnections shifted towards high heterogeneity with elongated, clustered and looped mitochondria. These morphological changes were found to correlate directly with functional alterations. Mitochondrial membrane potential and ATP generation were significantly reduced in INS1 cells after Drp1down-regulation. Finally, a significant loss of glucose-stimulated insulin secretion was demonstrated in INS1 cells and mouse pancreatic islets. In conclusion, Drp1 expression is important in pancreatic beta cells to maintain the regulation of insulin secretion.
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Affiliation(s)
- Florian Reinhardt
- Institute of Medical Biochemistry and Molecular Biology, University of Rostock, D-18057 Rostock, Germany
| | - Julia Schultz
- Institute of Medical Biochemistry and Molecular Biology, University of Rostock, D-18057 Rostock, Germany
| | - Rica Waterstradt
- Institute of Medical Biochemistry and Molecular Biology, University of Rostock, D-18057 Rostock, Germany
| | - Simone Baltrusch
- Institute of Medical Biochemistry and Molecular Biology, University of Rostock, D-18057 Rostock, Germany.
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Peiris H, Duffield MD, Fadista J, Jessup CF, Kashmir V, Genders AJ, McGee SL, Martin AM, Saiedi M, Morton N, Carter R, Cousin MA, Kokotos AC, Oskolkov N, Volkov P, Hough TA, Fisher EMC, Tybulewicz VLJ, Busciglio J, Coskun PE, Becker A, Belichenko PV, Mobley WC, Ryan MT, Chan JY, Laybutt DR, Coates PT, Yang S, Ling C, Groop L, Pritchard MA, Keating DJ. A Syntenic Cross Species Aneuploidy Genetic Screen Links RCAN1 Expression to β-Cell Mitochondrial Dysfunction in Type 2 Diabetes. PLoS Genet 2016; 12:e1006033. [PMID: 27195491 PMCID: PMC4873152 DOI: 10.1371/journal.pgen.1006033] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/18/2016] [Indexed: 12/20/2022] Open
Abstract
Type 2 diabetes (T2D) is a complex metabolic disease associated with obesity, insulin resistance and hypoinsulinemia due to pancreatic β-cell dysfunction. Reduced mitochondrial function is thought to be central to β-cell dysfunction. Mitochondrial dysfunction and reduced insulin secretion are also observed in β-cells of humans with the most common human genetic disorder, Down syndrome (DS, Trisomy 21). To identify regions of chromosome 21 that may be associated with perturbed glucose homeostasis we profiled the glycaemic status of different DS mouse models. The Ts65Dn and Dp16 DS mouse lines were hyperglycemic, while Tc1 and Ts1Rhr mice were not, providing us with a region of chromosome 21 containing genes that cause hyperglycemia. We then examined whether any of these genes were upregulated in a set of ~5,000 gene expression changes we had identified in a large gene expression analysis of human T2D β-cells. This approach produced a single gene, RCAN1, as a candidate gene linking hyperglycemia and functional changes in T2D β-cells. Further investigations demonstrated that RCAN1 methylation is reduced in human T2D islets at multiple sites, correlating with increased expression. RCAN1 protein expression was also increased in db/db mouse islets and in human and mouse islets exposed to high glucose. Mice overexpressing RCAN1 had reduced in vivo glucose-stimulated insulin secretion and their β-cells displayed mitochondrial dysfunction including hyperpolarised membrane potential, reduced oxidative phosphorylation and low ATP production. This lack of β-cell ATP had functional consequences by negatively affecting both glucose-stimulated membrane depolarisation and ATP-dependent insulin granule exocytosis. Thus, from amongst the myriad of gene expression changes occurring in T2D β-cells where we had little knowledge of which changes cause β-cell dysfunction, we applied a trisomy 21 screening approach which linked RCAN1 to β-cell mitochondrial dysfunction in T2D.
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Affiliation(s)
- Heshan Peiris
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Michael D. Duffield
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | | | - Claire F. Jessup
- Islet Biology Laboratory, Department of Anatomy and Histology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Vinder Kashmir
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Amanda J. Genders
- Metabolic Remodelling Laboratory, Metabolic Research Unit, School of Medicine, Deakin University, Geelong, Australia
| | - Sean L. McGee
- Metabolic Remodelling Laboratory, Metabolic Research Unit, School of Medicine, Deakin University, Geelong, Australia
- Metabolism and Inflammation Program, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Alyce M. Martin
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Madiha Saiedi
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Nicholas Morton
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Roderick Carter
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Michael A. Cousin
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Alexandros C. Kokotos
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Petr Volkov
- Lund University Diabetes Centre, Malmö, Sweden
| | - Tertius A. Hough
- Mary Lyon Centre Pathology, MRC Harwell, Harwell Oxford Science Park, Oxford, United Kingdom
| | - Elizabeth M. C. Fisher
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
| | - Victor L. J. Tybulewicz
- Francis Crick Institute, Mill Hill, London, United Kingdom
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Jorge Busciglio
- Department of Neurobiology and Behaviour, University of California, Irvine, Irvine, California, United States of America
| | - Pinar E. Coskun
- Department of Neurobiology and Behaviour, University of California, Irvine, Irvine, California, United States of America
| | - Ann Becker
- Department of Neurosciences School of Medicine, University of California, San Diego, San Diego, California, United States of America
| | - Pavel V. Belichenko
- Department of Neurosciences School of Medicine, University of California, San Diego, San Diego, California, United States of America
| | - William C. Mobley
- Department of Neurosciences School of Medicine, University of California, San Diego, San Diego, California, United States of America
| | - Michael T. Ryan
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Jeng Yie Chan
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - D. Ross Laybutt
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - P. Toby Coates
- Clinical and Experimental Transplantation Group, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia, Australia
| | - Sijun Yang
- Animal Experiment Center, Animal Biosafety Level-III Laboratory, Wuhan University, Wuhan, China
| | | | - Leif Groop
- Lund University Diabetes Centre, Malmö, Sweden
| | - Melanie A. Pritchard
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Damien J. Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
- South Australian Health and Medical Research Institute, Adelaide, Australia
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Pepin É, Al-Mass A, Attané C, Zhang K, Lamontagne J, Lussier R, Madiraju SRM, Joly E, Ruderman NB, Sladek R, Prentki M, Peyot ML. Pancreatic β-Cell Dysfunction in Diet-Induced Obese Mice: Roles of AMP-Kinase, Protein Kinase Cε, Mitochondrial and Cholesterol Metabolism, and Alterations in Gene Expression. PLoS One 2016; 11:e0153017. [PMID: 27043434 PMCID: PMC4820227 DOI: 10.1371/journal.pone.0153017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/22/2016] [Indexed: 12/27/2022] Open
Abstract
Diet induced obese (DIO) mice can be stratified according to their weight gain in response to high fat diet as low responders (LDR) and high responders (HDR). This allows the study of β-cell failure and the transitions to prediabetes (LDR) and early diabetes (HDR). C57BL/6N mice were fed for 8 weeks with a normal chow diet (ND) or a high fat diet and stratified as LDR and HDR. Freshly isolated islets from ND, LDR and HDR mice were studied ex-vivo for mitochondrial metabolism, AMPK activity and signalling, the expression and activity of key enzymes of energy metabolism, cholesterol synthesis, and mRNA profiling. Severely compromised glucose-induced insulin secretion in HDR islets, as compared to ND and LDR islets, was associated with suppressed AMP-kinase activity. HDR islets also showed reduced acetyl-CoA carboxylase activity and enhanced activity of 3-hydroxy-3-methylglutaryl-CoA reductase, which led respectively to elevated fatty acid oxidation and increased cholesterol biosynthesis. HDR islets also displayed mitochondrial membrane hyperpolarization and reduced ATP turnover in the presence of elevated glucose. Expression of protein kinase Cε, which reduces both lipolysis and production of signals for insulin secretion, was elevated in DIO islets. Genes whose expression increased or decreased by more than 1.2-fold were minor between LDR and ND islets (17 differentially expressed), but were prominent between HDR and ND islets (1508 differentially expressed). In HDR islets, particularly affected genes were related to cell cycle and proliferation, AMPK signaling, mitochondrial metabolism and cholesterol metabolism. In conclusion, chronically reduced AMPK activity, mitochondrial dysfunction, elevated cholesterol biosynthesis in islets, and substantial alterations in gene expression accompany β-cell failure in HDR islets. The β-cell compensation process in the prediabetic state (LDR) is largely independent of transcriptional adaptive changes, whereas the transition to early diabetes (HDR) is associated with major alterations in gene expression.
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Affiliation(s)
- Émilie Pepin
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
| | - Anfal Al-Mass
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
- Departments of Medicine and Human Genetics, McGill University, Montreal, Québec, Canada
| | - Camille Attané
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
| | - Kezhuo Zhang
- Departments of Medicine and Human Genetics, McGill University, Montreal, Québec, Canada
| | - Julien Lamontagne
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
| | - Roxane Lussier
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
| | - S. R. Murthy Madiraju
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
| | - Erik Joly
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
| | - Neil B. Ruderman
- Departments of Medicine and Physiology and Biophysics, Boston University School of Medicine and Diabetes Unit, Boston Medical Center, Boston, MA, United States of America
| | - Robert Sladek
- Departments of Medicine and Human Genetics, McGill University, Montreal, Québec, Canada
| | - Marc Prentki
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
- Departments of Nutrition, Biochemistry and Molecular Medicine, Faculty of Medicine, University of Montréal, Montreal, Québec, Canada
- * E-mail: (MP); (MLP)
| | - Marie-Line Peyot
- Montreal Diabetes Research Center and Centre de Recherche du CHUM, Montréal, Québec, Canada
- * E-mail: (MP); (MLP)
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43
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Popkov VA, Plotnikov EY, Lyamzaev KG, Silachev DN, Zorova LD, Pevzner IB, Jankauskas SS, Zorov SD, Babenko VA, Zorov DB. Mitodiversity. BIOCHEMISTRY (MOSCOW) 2016; 80:532-41. [PMID: 26071770 DOI: 10.1134/s000629791505003x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Here, in addition to the previously coined term "mitobiota", we introduce the term "mitodiversity" for various phenotypic and genetic heterogeneities of mitochondria within the same cell or organ. Based on data on the mitochondrial transmembrane potential determined both in situ and in vitro under normal conditions and after organ ischemia/reperfusion, such heterogeneity is most evident under pathologic conditions. Herein, a part of the mitochondrial population with transmembrane potential typical of the normal state is sustained even under a pathological condition that, perhaps, underlies the development of ways of reversing pathology back to the normal state. The membrane potentials of isolated mitochondria were shown to directly correlate with the magnitude of side-scattered light depicting internal structure of mitochondria. We analyzed possible interpretations of data on mitochondrial membrane potential obtained using fluorescent probes. We suggest a possible mechanism underlying retention of fluorescent probes inside the cells and mitochondria.
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Affiliation(s)
- V A Popkov
- Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119991, Russia
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44
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Farnsworth NL, Walter RL, Hemmati A, Westacott MJ, Benninger RKP. Low Level Pro-inflammatory Cytokines Decrease Connexin36 Gap Junction Coupling in Mouse and Human Islets through Nitric Oxide-mediated Protein Kinase Cδ. J Biol Chem 2016; 291:3184-96. [PMID: 26668311 PMCID: PMC4751367 DOI: 10.1074/jbc.m115.679506] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 12/07/2015] [Indexed: 11/06/2022] Open
Abstract
Pro-inflammatory cytokines contribute to the decline in islet function during the development of diabetes. Cytokines can disrupt insulin secretion and calcium dynamics; however, the mechanisms underlying this are poorly understood. Connexin36 gap junctions coordinate glucose-induced calcium oscillations and pulsatile insulin secretion across the islet. Loss of gap junction coupling disrupts these dynamics, similar to that observed during the development of diabetes. This study investigates the mechanisms by which pro-inflammatory cytokines mediate gap junction coupling. Specifically, as cytokine-induced NO can activate PKCδ, we aimed to understand the role of PKCδ in modulating cytokine-induced changes in gap junction coupling. Isolated mouse and human islets were treated with varying levels of a cytokine mixture containing TNF-α, IL-1β, and IFN-γ. Islet dysfunction was measured by insulin secretion, calcium dynamics, and gap junction coupling. Modulators of PKCδ and NO were applied to determine their respective roles in modulating gap junction coupling. High levels of cytokines caused cell death and decreased insulin secretion. Low levels of cytokine treatment disrupted calcium dynamics and decreased gap junction coupling, in the absence of disruptions to insulin secretion. Decreases in gap junction coupling were dependent on NO-regulated PKCδ, and altered membrane organization of connexin36. This study defines several mechanisms underlying the disruption to gap junction coupling under conditions associated with the development of diabetes. These mechanisms will allow for greater understanding of islet dysfunction and suggest ways to ameliorate this dysfunction during the development of diabetes.
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Affiliation(s)
- Nikki L Farnsworth
- From the Barbara Davis Center for Childhood Diabetes, Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Rachelle L Walter
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Alireza Hemmati
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Matthew J Westacott
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Richard K P Benninger
- From the Barbara Davis Center for Childhood Diabetes, Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
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45
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Sukhorukov VM, Meyer-Hermann M. Structural Heterogeneity of Mitochondria Induced by the Microtubule Cytoskeleton. Sci Rep 2015; 5:13924. [PMID: 26355039 PMCID: PMC4565121 DOI: 10.1038/srep13924] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 08/11/2015] [Indexed: 01/13/2023] Open
Abstract
By events of fusion and fission mitochondria generate a partially interconnected, irregular network of poorly specified architecture. Here, its organization is examined theoretically by taking into account the physical association of mitochondria with microtubules. Parameters of the cytoskeleton mesh are derived from the mechanics of single fibers. The model of the mitochondrial reticulum is formulated in terms of a dynamic spatial graph. The graph dynamics is modulated by the density of microtubules and their crossings. The model reproduces the full spectrum of experimentally found mitochondrial configurations. In centrosome-organized cells, the chondriome is predicted to develop strong structural inhomogeneity between the cell center and the periphery. An integrated analysis of the cytoskeletal and the mitochondrial components reveals that the structure of the reticulum depends on the balance between anterograde and retrograde motility of mitochondria on microtubules, in addition to fission and fusion. We propose that it is the combination of the two processes that defines synergistically the mitochondrial structure, providing the cell with ample capabilities for its regulative adaptation.
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Affiliation(s)
- Valerii M. Sukhorukov
- Department of Systems Immunology and Braunschweig Integrated Centre
of Systems Biology, Helmholtz Centre for Infection Research,
Inhoffenstr. 7, 38124
Braunschweig, Germany
- Frankfurt Institute for Advanced Studies, Goethe University of
Frankfurt am Main, Ruth-Moufang-Str. 1, 60438
Frankfurt am Main, Germany
| | - Michael Meyer-Hermann
- Department of Systems Immunology and Braunschweig Integrated Centre
of Systems Biology, Helmholtz Centre for Infection Research,
Inhoffenstr. 7, 38124
Braunschweig, Germany
- Frankfurt Institute for Advanced Studies, Goethe University of
Frankfurt am Main, Ruth-Moufang-Str. 1, 60438
Frankfurt am Main, Germany
- Institute for Biochemistry, Biotechnology and Bioinformatics,
Technische Universität Braunschweig, Langer Kamp 19b,
38106
Braunschweig, Germany
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46
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Affiliation(s)
- Alexandra E Butler
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Sangeeta Dhawan
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
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47
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Swisa A, Granot Z, Tamarina N, Sayers S, Bardeesy N, Philipson L, Hodson DJ, Wikstrom JD, Rutter GA, Leibowitz G, Glaser B, Dor Y. Loss of Liver Kinase B1 (LKB1) in Beta Cells Enhances Glucose-stimulated Insulin Secretion Despite Profound Mitochondrial Defects. J Biol Chem 2015; 290:20934-20946. [PMID: 26139601 PMCID: PMC4543653 DOI: 10.1074/jbc.m115.639237] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Indexed: 12/25/2022] Open
Abstract
The tumor suppressor liver kinase B1 (LKB1) is an important regulator of pancreatic β cell biology. LKB1-dependent phosphorylation of distinct AMPK (adenosine monophosphate-activated protein kinase) family members determines proper β cell polarity and restricts β cell size, total β cell mass, and glucose-stimulated insulin secretion (GSIS). However, the full spectrum of LKB1 effects and the mechanisms involved in the secretory phenotype remain incompletely understood. We report here that in the absence of LKB1 in β cells, GSIS is dramatically and persistently improved. The enhancement is seen both in vivo and in vitro and cannot be explained by altered cell polarity, increased β cell number, or increased insulin content. Increased secretion does require membrane depolarization and calcium influx but appears to rely mostly on a distal step in the secretion pathway. Surprisingly, enhanced GSIS is seen despite profound defects in mitochondrial structure and function in LKB1-deficient β cells, expected to greatly diminish insulin secretion via the classic triggering pathway. Thus LKB1 is essential for mitochondrial homeostasis in β cells and in parallel is a powerful negative regulator of insulin secretion. This study shows that β cells can be manipulated to enhance GSIS to supra-normal levels even in the face of defective mitochondria and without deterioration over months.
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Affiliation(s)
- Avital Swisa
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Zvi Granot
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Natalia Tamarina
- Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - Sophie Sayers
- Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, SW7 2AZ, London, United Kingdom
| | - Nabeel Bardeesy
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts 02114
| | - Louis Philipson
- Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - David J Hodson
- Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, SW7 2AZ, London, United Kingdom
| | - Jakob D Wikstrom
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel; Unit of Dermatology and Venereology, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, 171 77 Stockholm, Sweden
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, SW7 2AZ, London, United Kingdom
| | - Gil Leibowitz
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Benjamin Glaser
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Yuval Dor
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
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48
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Mitochondrial quality control: Easy come, easy go. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2802-11. [PMID: 25596427 DOI: 10.1016/j.bbamcr.2014.12.041] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/09/2014] [Accepted: 12/25/2014] [Indexed: 02/03/2023]
Abstract
"Friends come and go but enemies accumulate." - Arthur Bloch Mitochondrial networks in eukaryotic cells are maintained via regular cycles of degradation and biogenesis. These complex processes function in concert with one another to eliminate dysfunctional mitochondria in a specific and targeted manner and coordinate the biogenesis of new organelles. This review covers the two aspects of mitochondrial turnover, focusing on the main pathways and mechanisms involved. The review also summarizes the current methods and techniques for analyzing mitochondrial turnover in vivo and in vitro, from the whole animal proteome level to the level of single organelle.
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49
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MitoTimer: a novel protein for monitoring mitochondrial turnover in the heart. J Mol Med (Berl) 2014; 93:271-8. [PMID: 25479961 PMCID: PMC4333239 DOI: 10.1007/s00109-014-1230-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 10/19/2014] [Accepted: 11/12/2014] [Indexed: 01/17/2023]
Abstract
Mitochondrial quality control refers to the coordinated cellular systems involved in maintaining a population of healthy mitochondria. In addition to mitochondrial protein chaperones (Hsp10, Hsp60, and others) and proteases (Lon, AAA proteases) needed for refolding or degrading individual proteins, mitochondrial integrity is maintained through the regulation of protein import via the TOM/TIM complex and protein redistribution across the network via fusion and fission and through mitophagy and biogenesis, key determinants of mitochondrial turnover. A growing number of studies point to the importance of mitochondrial dynamics (fusion/fission) and mitochondrial autophagy in the heart. Mitochondrial biogenesis must keep pace with mitophagy in order to maintain a stable number of mitochondria. In this review, we will discuss the use of MitoTimer as a tool to monitor mitochondrial turnover.
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50
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Fealy CE, Mulya A, Lai N, Kirwan JP. Exercise training decreases activation of the mitochondrial fission protein dynamin-related protein-1 in insulin-resistant human skeletal muscle. J Appl Physiol (1985) 2014; 117:239-45. [PMID: 24947026 PMCID: PMC4122691 DOI: 10.1152/japplphysiol.01064.2013] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 06/12/2014] [Indexed: 02/03/2023] Open
Abstract
Defects in mitochondrial dynamics, the processes of fission, fusion, and mitochondrial autophagy, may contribute to metabolic disease including type 2 diabetes. Dynamin-related protein-1 (Drp1) is a GTPase protein that plays a central role in mitochondrial fission. We hypothesized that aerobic exercise training would decrease Drp1 Ser(616) phosphorylation and increase fat oxidation and insulin sensitivity in obese (body mass index: 34.6 ± 0.8 kg/m(2)) insulin-resistant adults. Seventeen subjects performed supervised exercise for 60 min/day, 5 days/wk at 80-85% of maximal heart rate for 12 wk. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp, and fat oxidation was determined by indirect calorimetry. Skeletal muscle biopsies were obtained from the vastus lateralis muscle before and after the 12-wk program. The exercise intervention increased insulin sensitivity 2.1 ± 0.2-fold (P < 0.01) and fat oxidation 1.3 ± 0.3-fold (P < 0.01). Phosphorylation of Drp1 at Ser(616) was decreased (pre vs. post: 0.81 ± 0.15 vs. 0.58 ± 0.14 arbitrary units; P < 0.05) following the intervention. Furthermore, reductions in Drp1 Ser(616) phosphorylation were negatively correlated with increases in fat oxidation (r = -0.58; P < 0.05) and insulin sensitivity (rho = -0.52; P < 0.05). We also examined expression of genes related to mitochondrial dynamics. Dynamin1-like protein (DNM1L; P < 0.01), the gene that codes for Drp1, and Optic atrophy 1 (OPA1; P = 0.05) were significantly upregulated following the intervention, while there was a trend towards an increase in expression of both mitofusin protein MFN1 (P = 0.08) and MFN2 (P = 0.07). These are the first data to suggest that lifestyle-mediated improvements in substrate metabolism and insulin sensitivity in obese insulin-resistant adults may be regulated through decreased activation of the mitochondrial fission protein Drp1.
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Affiliation(s)
- Ciaran E Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Department of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Anny Mulya
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Metabolic Translational Research Center, Cleveland Clinic, Cleveland, Ohio; and
| | - Nicola Lai
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - John P Kirwan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Metabolic Translational Research Center, Cleveland Clinic, Cleveland, Ohio; and
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