1
|
Gureev AP, Alimova AA, Silachev DN, Plotnikov EY. Noncoupled Mitochondrial Respiration as Therapeutic Approach for the Treatment of Metabolic Diseases: Focus on Transgenic Animal Models. Int J Mol Sci 2023; 24:16491. [PMID: 38003681 PMCID: PMC10671337 DOI: 10.3390/ijms242216491] [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: 10/10/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023] Open
Abstract
Mitochondrial dysfunction contributes to numerous chronic diseases, and mitochondria are targets for various toxins and xenobiotics. Therefore, the development of drugs or therapeutic strategies targeting mitochondria is an important task in modern medicine. It is well known that the primary, although not the sole, function of mitochondria is ATP generation, which is achieved by coupled respiration. However, a high membrane potential can lead to uncontrolled reactive oxygen species (ROS) production and associated dysfunction. For over 50 years, scientists have been studying various synthetic uncouplers, and for more than 30 years, uncoupling proteins that are responsible for uncoupled respiration in mitochondria. Additionally, the proteins of the mitochondrial alternative respiratory pathway exist in plant mitochondria, allowing noncoupled respiration, in which electron flow is not associated with membrane potential formation. Over the past two decades, advances in genetic engineering have facilitated the creation of various cellular and animal models that simulate the effects of uncoupled and noncoupled respiration in different tissues under various disease conditions. In this review, we summarize and discuss the findings obtained from these transgenic models. We focus on the advantages and limitations of transgenic organisms, the observed physiological and biochemical changes, and the therapeutic potential of uncoupled and noncoupled respiration.
Collapse
Affiliation(s)
- Artem P. Gureev
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, 394018 Voronezh, Russia; (A.P.G.); (A.A.A.)
- Laboratory of Metagenomics and Food Biotechnology, Voronezh State University of Engineering Technologies, 394036 Voronezh, Russia
| | - Alina A. Alimova
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, 394018 Voronezh, Russia; (A.P.G.); (A.A.A.)
- Laboratory of Metagenomics and Food Biotechnology, Voronezh State University of Engineering Technologies, 394036 Voronezh, Russia
| | - Denis N. Silachev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia;
| | - Egor Y. Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia;
| |
Collapse
|
2
|
Knyazev DG, Silverstein TP, Brescia S, Maznichenko A, Pohl P. A New Theory about Interfacial Proton Diffusion Revisited: The Commonly Accepted Laws of Electrostatics and Diffusion Prevail. Biomolecules 2023; 13:1641. [PMID: 38002323 PMCID: PMC10669390 DOI: 10.3390/biom13111641] [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: 09/26/2023] [Revised: 11/02/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
The high propensity of protons to stay at interfaces has attracted much attention over the decades. It enables long-range interfacial proton diffusion without relying on titratable residues or electrostatic attraction. As a result, various phenomena manifest themselves, ranging from spillover in material sciences to local proton circuits between proton pumps and ATP synthases in bioenergetics. In an attempt to replace all existing theoretical and experimental insight into the origin of protons' preference for interfaces, TELP, the "Transmembrane Electrostatically-Localized Protons" hypothesis, has been proposed. The TELP hypothesis envisions static H+ and OH- layers on opposite sides of interfaces that are up to 75 µm thick. Yet, the separation at which the electrostatic interaction between two elementary charges is comparable in magnitude to the thermal energy is more than two orders of magnitude smaller and, as a result, the H+ and OH- layers cannot mutually stabilize each other, rendering proton accumulation at the interface energetically unfavorable. We show that (i) the law of electroneutrality, (ii) Fick's law of diffusion, and (iii) Coulomb's law prevail. Using them does not hinder but helps to interpret previously published experimental results, and also helps us understand the high entropy release barrier enabling long-range proton diffusion along the membrane surface.
Collapse
Affiliation(s)
- Denis G. Knyazev
- Institute of Biophysics, Johannes Kepler University, 4020 Linz, Austria; (D.G.K.); (S.B.); (A.M.)
| | | | - Stefania Brescia
- Institute of Biophysics, Johannes Kepler University, 4020 Linz, Austria; (D.G.K.); (S.B.); (A.M.)
| | - Anna Maznichenko
- Institute of Biophysics, Johannes Kepler University, 4020 Linz, Austria; (D.G.K.); (S.B.); (A.M.)
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University, 4020 Linz, Austria; (D.G.K.); (S.B.); (A.M.)
| |
Collapse
|
3
|
Zhang J, Pan L, Zhang Q, Zhao Y, Wang W, Lin N, Zhang S, Wu Q. MFN2 deficiency affects calcium homeostasis in lung adenocarcinoma cells via downregulation of UCP4. FEBS Open Bio 2023. [PMID: 36877954 DOI: 10.1002/2211-5463.13591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 12/29/2022] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Mitofusin-2 (MFN2) is a transmembrane GTPase that regulates mitochondrial fusion and thereby modulates mitochondrial function. However, the role of MFN2 in lung adenocarcinoma remains controversial. Here, we investigated the effect of MFN2 regulation on mitochondria in lung adenocarcinoma. We found that MFN2 deficiency resulted in decreased UCP4 expression and mitochondrial dysfunction in A549 and H1975 cells. UCP4 overexpression restored ATP and intracellular calcium concentration, but not mtDNA copy number, mitochondrial membrane potential or reactive oxygen species level. Furthermore, mass spectrometry analysis identified 460 overlapping proteins after independent overexpression of MFN2 and UCP4; these proteins were significantly enriched in the cytoskeleton, energy production, and calponin homology (CH) domains. Moreover, the calcium signaling pathway was confirmed to be enriched in KEGG pathway analysis. We also found by protein-protein interaction network analysis that PINK1 may be a key regulator of MFN2- and UCP4-mediated calcium homeostasis. Furthermore, PINK1 increased MFN2/UCP4-mediated intracellular Ca2+ concentration in A549 and H1975 cells. Finally, we demonstrated that low expression levels of MFN2 and UCP4 in lung adenocarcinoma are associated with poor clinical prognosis. In conclusion, our data suggest not only a potential role of MFN2 and UCP4 in co-regulating calcium homeostasis in lung adenocarcinoma but also their potential use as therapeutic targets in lung cancer.
Collapse
Affiliation(s)
- Jingjing Zhang
- Department of Translational Medicine Research Center, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Oncology, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou, China
| | - Lifang Pan
- Department of Translational Medicine Research Center, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Qiang Zhang
- Department of Pharmaceutical and Chemical Engineering, Zhengzhou Business Technicians Institute, China
| | - Yanyan Zhao
- Department of Translational Medicine Research Center, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Oncology, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenwen Wang
- Department of Translational Medicine Research Center, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Oncology, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou, China
| | - Nengming Lin
- Department of Translational Medicine Research Center, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Oncology, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou, China
| | - Shirong Zhang
- Department of Translational Medicine Research Center, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Oncology, Affiliated Hangzhou First People's Hospital, Cancer Center, Zhejiang University School of Medicine, Hangzhou, China
| | - Qiong Wu
- Department of Integrated Chinese and Western Medicine, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Hangzhou, China
| |
Collapse
|
4
|
Weichselbaum E, Galimzyanov T, Batishchev OV, Akimov SA, Pohl P. Proton Migration on Top of Charged Membranes. Biomolecules 2023; 13:biom13020352. [PMID: 36830721 PMCID: PMC9953355 DOI: 10.3390/biom13020352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/23/2023] [Accepted: 02/07/2023] [Indexed: 02/15/2023] Open
Abstract
Proton relay between interfacial water molecules allows rapid two-dimensional diffusion. An energy barrier, ΔGr‡, opposes proton-surface-to-bulk release. The ΔGr‡-regulating mechanism thus far has remained unknown. Here, we explored the effect interfacial charges have on ΔGr‡'s enthalpic and entropic constituents, ΔGH‡ and ΔGS‡, respectively. A light flash illuminating a micrometer-sized membrane patch of a free-standing planar lipid bilayer released protons from an adsorbed hydrophobic caged compound. A lipid-anchored pH-sensitive dye reported protons' arrival at a distant membrane patch. Introducing net-negative charges to the bilayer doubled ΔGH‡, while positive net charges decreased ΔGH‡. The accompanying variations in ΔGS‡ compensated for the ΔGH‡ modifications so that ΔGr‡ was nearly constant. The increase in the entropic component of the barrier is most likely due to the lower number and strength of hydrogen bonds known to be formed by positively charged residues as compared to negatively charged moieties. The resulting high ΔGr‡ ensured interfacial proton diffusion for all measured membranes. The observation indicates that the variation in membrane surface charge alone is a poor regulator of proton traffic along the membrane surface.
Collapse
Affiliation(s)
- Ewald Weichselbaum
- Institute of Biophysics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Timur Galimzyanov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
- Department of Theoretical Physics and Quantum Technologies, National University of Science and Technology “MISiS”, Moscow 119991, Russia
| | - Oleg V. Batishchev
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
| | - Sergey A. Akimov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
- Department of Theoretical Physics and Quantum Technologies, National University of Science and Technology “MISiS”, Moscow 119991, Russia
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, 4040 Linz, Austria
- Correspondence:
| |
Collapse
|
5
|
Zhai R, Fang B, Lai Y, Peng B, Bai H, Liu X, Li L, Huang W. Small-molecule fluorogenic probes for mitochondrial nanoscale imaging. Chem Soc Rev 2023; 52:942-972. [PMID: 36514947 DOI: 10.1039/d2cs00562j] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mitochondria are inextricably linked to the development of diseases and cell metabolism disorders. Super-resolution imaging (SRI) is crucial in enhancing our understanding of mitochondrial ultrafine structures and functions. In addition to high-precision instruments, super-resolution microscopy relies heavily on fluorescent materials with unique photophysical properties. Small-molecule fluorogenic probes (SMFPs) have excellent properties that make them ideal for mitochondrial SRI. This paper summarizes recent advances in the field of SMFPs, with a focus on the chemical and spectroscopic properties required for mitochondrial SRI. Finally, we discuss future challenges in this field, including the design principles of SMFPs and nanoscopic techniques.
Collapse
Affiliation(s)
- Rongxiu Zhai
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China.
| | - Bin Fang
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China. .,School of Materials Science and Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an 710072, China
| | - Yaqi Lai
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China.
| | - Bo Peng
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China.
| | - Hua Bai
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China.
| | - Xiaowang Liu
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China.
| | - Lin Li
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China. .,The Institute of Flexible Electronics (IFE, Future Technologies), Xiamen University, Xiamen 361005, Fujian, China
| | - Wei Huang
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, China. .,The Institute of Flexible Electronics (IFE, Future Technologies), Xiamen University, Xiamen 361005, Fujian, China
| |
Collapse
|
6
|
Zhao H, Ma D, Xie J, Sanchez O, Huang F, Yuan C. Live-Cell Probe for In Situ Single-Cell Monitoring of Mitochondrial DNA Methylation. ACS Sens 2021; 6:3575-3586. [PMID: 34586782 DOI: 10.1021/acssensors.1c00731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Mitochondria, as the center of energy production, play an important role in cell homeostasis by regulating the cellular metabolism and mediating the cellular response to stress. Epigenetic changes such as DNA and histone methylation have been increasingly recognized to play a significant role in homeostasis and stress response. The cross-talking between the metabolome and the epigenome has attracted significant attention in recent years but with a major focus on how metabolism contributes to epigenomic changes. Few studies have focused on how epigenetic modifications may alter the mitochondrial composition and activity. In this work, we designed a novel probe targeting methylated CpGs of mitochondrial DNA (mtDNA). We demonstrated the capability of our probe to reveal the spatial distribution of methylated mtDNA and capture the mtDNA methylation changes at a single-cell level. We were also able to track single-cell mtDNA and nDNA methylation simultaneously and discovered the unsynchronized dynamics of the nucleus and mitochondria. Our tool offers a unique opportunity to understand the epigenetic regulation of mtDNA and its dynamic response to the microenvironment and cellular changes.
Collapse
Affiliation(s)
- Han Zhao
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Donghan Ma
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Junkai Xie
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Oscar Sanchez
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Fang Huang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue University Center for Cancer Research, West Lafayette, Indiana 47907, United States
| | - Chongli Yuan
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue University Center for Cancer Research, West Lafayette, Indiana 47907, United States
| |
Collapse
|
7
|
Bogorodskiy A, Okhrimenko I, Maslov I, Maliar N, Burkatovskii D, von Ameln F, Schulga A, Jakobs P, Altschmied J, Haendeler J, Katranidis A, Sorokin I, Mishin A, Gordeliy V, Büldt G, Voos W, Gensch T, Borshchevskiy V. Accessing Mitochondrial Protein Import in Living Cells by Protein Microinjection. Front Cell Dev Biol 2021; 9:698658. [PMID: 34307376 PMCID: PMC8292824 DOI: 10.3389/fcell.2021.698658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/15/2021] [Indexed: 01/06/2023] Open
Abstract
Mitochondrial protein biogenesis relies almost exclusively on the expression of nuclear-encoded polypeptides. The current model postulates that most of these proteins have to be delivered to their final mitochondrial destination after their synthesis in the cytoplasm. However, the knowledge of this process remains limited due to the absence of proper experimental real-time approaches to study mitochondria in their native cellular environment. We developed a gentle microinjection procedure for fluorescent reporter proteins allowing a direct non-invasive study of protein transport in living cells. As a proof of principle, we visualized potential-dependent protein import into mitochondria inside intact cells in real-time. We validated that our approach does not distort mitochondrial morphology and preserves the endogenous expression system as well as mitochondrial protein translocation machinery. We observed that a release of nascent polypeptides chains from actively translating cellular ribosomes by puromycin strongly increased the import rate of the microinjected pre-protein. This suggests that a substantial amount of mitochondrial translocase complexes was involved in co-translational protein import of endogenously expressed pre-proteins. Our protein microinjection method opens new possibilities to study the role of mitochondrial protein import in cell models of various pathological conditions as well as aging processes.
Collapse
Affiliation(s)
- Andrey Bogorodskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ivan Okhrimenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ivan Maslov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Nina Maliar
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Dmitrii Burkatovskii
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Florian von Ameln
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- IUF–Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Alexey Schulga
- Molecular Immunology Laboratory, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Philipp Jakobs
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Joachim Altschmied
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- IUF–Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Judith Haendeler
- Environmentally-Induced Cardiovascular Degeneration, Central Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, University Hospital and Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Alexandros Katranidis
- Institute of Biological Information Processing (IBI-6: Cellular Structural Biology), Forschungszentrum Jülich, Jülich, Germany
| | - Ivan Sorokin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexey Mishin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Valentin Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Georg Büldt
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Wolfgang Voos
- Institute of Biochemistry and Molecular Biology (IBMB), Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Thomas Gensch
- Institute of Biological Information Processing (IBI-1: Molecular and Cellular Physiology), Forschungszentrum Jülich, Jülich, Germany
| | - Valentin Borshchevskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
| |
Collapse
|
8
|
Palmer CS, Lou J, Kouskousis B, Pandzic E, Anderson AJ, Kang Y, Hinde E, Stojanovski D. Super-resolution microscopy reveals the arrangement of inner membrane protein complexes in mammalian mitochondria. J Cell Sci 2021; 134:jcs252197. [PMID: 34313317 DOI: 10.1242/jcs.252197] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 06/03/2021] [Indexed: 12/24/2022] Open
Abstract
The mitochondrial inner membrane is a protein-rich environment containing large multimeric complexes, including complexes of the mitochondrial electron transport chain, mitochondrial translocases and quality control machineries. Although the inner membrane is highly proteinaceous, with 40-60% of all mitochondrial proteins localised to this compartment, little is known about the spatial distribution and organisation of complexes in this environment. We set out to survey the arrangement of inner membrane complexes using stochastic optical reconstruction microscopy (STORM). We reveal that subunits of the TIM23 complex, TIM23 and TIM44 (also known as TIMM23 and TIMM44, respectively), and the complex IV subunit COXIV, form organised clusters and show properties distinct from the outer membrane protein TOM20 (also known as TOMM20). Density based cluster analysis indicated a bimodal distribution of TIM44 that is distinct from TIM23, suggesting distinct TIM23 subcomplexes. COXIV is arranged in larger clusters that are disrupted upon disruption of complex IV assembly. Thus, STORM super-resolution microscopy is a powerful tool for examining the nanoscale distribution of mitochondrial inner membrane complexes, providing a 'visual' approach for obtaining pivotal information on how mitochondrial complexes exist in a cellular context.
Collapse
Affiliation(s)
- Catherine S Palmer
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jieqiong Lou
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
- School of Physics, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Betty Kouskousis
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria 3004, Australia
- Monash Micro Imaging, Monash University, Clayton, Victoria 3168, Australia
| | - Elvis Pandzic
- Biomedical Imaging Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - Alexander J Anderson
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Yilin Kang
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Elizabeth Hinde
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
- School of Physics, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Diana Stojanovski
- Department of Biochemistry and Pharmacology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| |
Collapse
|
9
|
Mitochondrial Protein Abundance Gradients Require the Distribution of Separated Mitochondria. BIOLOGY 2021; 10:biology10070572. [PMID: 34201436 PMCID: PMC8301041 DOI: 10.3390/biology10070572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/14/2021] [Accepted: 06/18/2021] [Indexed: 01/06/2023]
Abstract
Mitochondria are highly dynamic organelles that interchange their contents mediated by fission and fusion. However, it has previously been shown that the mitochondria of cultured human epithelial cells exhibit a gradient in the relative abundance of several proteins, with the perinuclear mitochondria generally exhibiting a higher protein abundance than the peripheral mitochondria. The molecular mechanisms that are required for the establishment and the maintenance of such inner-cellular mitochondrial protein abundance gradients are unknown. We verified the existence of inner-cellular gradients in the abundance of clusters of the mitochondrial outer membrane protein Tom20 in the mitochondria of kidney epithelial cells from an African green monkey (Vero cells) using STED nanoscopy and confocal microscopy. We found that the Tom20 gradients are established immediately after cell division and require the presence of microtubules. Furthermore, the gradients are abrogated in hyperfused mitochondrial networks. Our results suggest that inner-cellular protein abundance gradients from the perinuclear to the peripheral mitochondria are established by the trafficking of individual mitochondria to their respective cellular destination.
Collapse
|
10
|
An H, Richardson A, Rajasekariah P, Zhong L, Fernando BSM, Macmillan A, Klotzsch E, Bryant K, Kaakoush NO, Tedla N. Nuclear Leukocyte Immunoglobulin-like Receptor A3 Is Monomeric and Is Involved in Multiple Layers of Regulated Gene Expression and Translation. J Proteome Res 2021; 20:3078-3089. [PMID: 33793249 DOI: 10.1021/acs.jproteome.0c00946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The leukocyte immunoglobulin-like receptor A3 (LILRA3) is a soluble protein primarily expressed by peripheral blood monocytes and is abundant in sera of healthy donors. Extracellular LILRA3 is anti-inflammatory and displays neuro-regenerative functions in vitro. However, its intracellular expression, distribution, and function(s) remain unknown. Using a combination of high-resolution confocal and super-resolution microscopy, we identified intracellular expression of native LILRA3 in the nucleus of peripheral blood monocytes and in vitro-derived macrophages. This unexpected nuclear localization of LILRA3 was confirmed in LILRA3-GFP-transfected HEK293T cells. Western blot of proteins fractionated from primary macrophages and the transfected HEK293T cells confirmed nuclear localization of the native and expressed LILRA3 proteins. Interestingly, most of the LILRA3 in the nucleus was in a monomeric form like the biologically active secreted protein, while that in the other cellular compartments was in mixed monomeric, dimeric, and oligomeric forms. The predominant presence of monomeric LILRA3 in the nucleus was independently corroborated in transfected live HEK293T cells using the number and molecular brightness (N&B) analysis method. Immunoprecipitation and mass spectrometric peptide sequencing studies revealed that nuclear LILRA3 co-immunoprecipitated with several nuclear proteins involved in host protein synthesis machinery via direct interactions to a key multifunctional RNA-binding protein, the Ewing sarcoma breakpoint region 1 protein (EWS) (data are available via ProteomeXchange with identifier PXD024602). The biological significance of the nuclear expression of LILRA3 and its interaction with these key proteins remain to be elucidated.
Collapse
Affiliation(s)
- Hongyan An
- Mechanisms of Diseases and Translational Research, School of Medical Sciences, Department of Pathology, UNSW, Sydney 2052, Australia
| | - Alexander Richardson
- Mechanisms of Diseases and Translational Research, School of Medical Sciences, Department of Pathology, UNSW, Sydney 2052, Australia
| | - Poornima Rajasekariah
- Mechanisms of Diseases and Translational Research, School of Medical Sciences, Department of Pathology, UNSW, Sydney 2052, Australia
| | - Ling Zhong
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, UNSW, Sydney 2052, Australia
| | - Bentotage Samitha M Fernando
- Mechanisms of Diseases and Translational Research, School of Medical Sciences, Department of Pathology, UNSW, Sydney 2052, Australia
| | - Alexander Macmillan
- Biomedical Imaging Facility, Mark Wainwright Analytical Centre, UNSW, Sydney 2052, Australia
| | - Enrico Klotzsch
- Laboratory of Applied Mechanobiology, Department for Health Sciences and Technology, ETH Zürich, Zürich 8093, Switzerland.,Institute for Biology, Experimental Biophysics/Mechanobiology, Humboldt University of Berlin, Berlin 10115, German
| | - Katherine Bryant
- Mechanisms of Diseases and Translational Research, School of Medical Sciences, Department of Pathology, UNSW, Sydney 2052, Australia
| | - Nadeem O Kaakoush
- Mechanisms of Diseases and Translational Research, School of Medical Sciences, Department of Pathology, UNSW, Sydney 2052, Australia
| | - Nicodemus Tedla
- Mechanisms of Diseases and Translational Research, School of Medical Sciences, Department of Pathology, UNSW, Sydney 2052, Australia
| |
Collapse
|
11
|
Abstract
Mitochondria are essential for eukaryotic life. These double-membrane organelles often form highly dynamic tubular networks interacting with many cellular structures. Their highly convoluted contiguous inner membrane compartmentalizes the organelle, which is crucial for mitochondrial function. Since the diameter of the mitochondrial tubules is generally close to the diffraction limit of light microscopy, it is often challenging, if not impossible, to visualize submitochondrial structures or protein distributions using conventional light microscopy. This renders super-resolution microscopy particularly valuable, and attractive, for studying mitochondria. Super-resolution microscopy encompasses a diverse set of approaches that extend resolution, as well as nanoscopy techniques that can even overcome the diffraction limit. In this review, we provide an overview of recent studies using super-resolution microscopy to investigate mitochondria, discuss the strengths and opportunities of the various methods in addressing specific questions in mitochondrial biology, and highlight potential future developments.
Collapse
Affiliation(s)
- Stefan Jakobs
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Clinic of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Till Stephan
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Clinic of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Peter Ilgen
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Clinic of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Christian Brüser
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Clinic of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany
| |
Collapse
|
12
|
Sancandi M, Uysal-Onganer P, Kraev I, Mercer A, Lange S. Protein Deimination Signatures in Plasma and Plasma-EVs and Protein Deimination in the Brain Vasculature in a Rat Model of Pre-Motor Parkinson's Disease. Int J Mol Sci 2020; 21:ijms21082743. [PMID: 32326590 PMCID: PMC7215947 DOI: 10.3390/ijms21082743] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/01/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023] Open
Abstract
The identification of biomarkers for early diagnosis of Parkinson’s disease (PD) is of pivotal importance for improving approaches for clinical intervention. The use of translatable animal models of pre-motor PD therefore offers optimal opportunities for novel biomarker discovery in vivo. Peptidylarginine deiminases (PADs) are a family of calcium-activated enzymes that contribute to protein misfolding through post-translational deimination of arginine to citrulline. Furthermore, PADs are an active regulator of extracellular vesicle (EV) release. Both protein deimination and extracellular vesicles (EVs) are gaining increased attention in relation to neurodegenerative diseases, including in PD, while roles in pre-motor PD have yet to be investigated. The current study aimed at identifying protein candidates of deimination in plasma and plasma-EVs in a rat model of pre-motor PD, to assess putative contributions of such post-translational changes in the early stages of disease. EV-cargo was further assessed for deiminated proteins as well as three key micro-RNAs known to contribute to inflammation and hypoxia (miR21, miR155, and miR210) and also associated with PD. Overall, there was a significant increase in circulating plasma EVs in the PD model compared with sham animals and inflammatory and hypoxia related microRNAs were significantly increased in plasma-EVs of the pre-motor PD model. A significantly higher number of protein candidates were deiminated in the pre-motor PD model plasma and plasma-EVs, compared with those in the sham animals. KEGG (Kyoto encyclopedia of genes and genomes) pathways identified for deiminated proteins in the pre-motor PD model were linked to “Alzheimer’s disease”, “PD”, “Huntington’s disease”, “prion diseases”, as well as for “oxidative phosphorylation”, “thermogenesis”, “metabolic pathways”, “Staphylococcus aureus infection”, gap junction, “platelet activation”, “apelin signalling”, “retrograde endocannabinoid signalling”, “systemic lupus erythematosus”, and “non-alcoholic fatty liver disease”. Furthermore, PD brains showed significantly increased staining for total deiminated proteins in the brain vasculature in cortex and hippocampus, as well as increased immunodetection of deiminated histone H3 in dentate gyrus and cortex. Our findings identify EVs and post-translational protein deimination as novel biomarkers in early pre-motor stages of PD.
Collapse
Affiliation(s)
- Marco Sancandi
- Department of Pharmacology, UCL School of Pharmacy, London WC1N 1AX, UK; (M.S.); (A.M.)
| | - Pinar Uysal-Onganer
- Cancer Research Group, School of Life Sciences, University of Westminster, London W1W 6XH, UK;
| | - Igor Kraev
- Electron Microscopy Suite, Faculty of Science, Technology, Engineering and Mathematics, Open University, Milton Keynes MK7 6AA, UK;
| | - Audrey Mercer
- Department of Pharmacology, UCL School of Pharmacy, London WC1N 1AX, UK; (M.S.); (A.M.)
| | - Sigrun Lange
- Tissue Architecture and Regeneration Research Group, School of Life Sciences, University of Westminster, London W1W 6XH, UK
- Correspondence: ; Tel.: +44-(0)207-911-5000 (ext. 64832)
| |
Collapse
|
13
|
Cell organelles as targets of mammalian cadmium toxicity. Arch Toxicol 2020; 94:1017-1049. [PMID: 32206829 DOI: 10.1007/s00204-020-02692-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
Abstract
Ever increasing environmental presence of cadmium as a consequence of industrial activities is considered a health hazard and is closely linked to deteriorating global health status. General animal and human cadmium exposure ranges from ingestion of foodstuffs sourced from heavily polluted hotspots and cigarette smoke to widespread contamination of air and water, including cadmium-containing microplastics found in household water. Cadmium is promiscuous in its effects and exerts numerous cellular perturbations based on direct interactions with macromolecules and its capacity to mimic or displace essential physiological ions, such as iron and zinc. Cell organelles use lipid membranes to form complex tightly-regulated, compartmentalized networks with specialized functions, which are fundamental to life. Interorganellar communication is crucial for orchestrating correct cell behavior, such as adaptive stress responses, and can be mediated by the release of signaling molecules, exchange of organelle contents, mechanical force generated through organelle shape changes or direct membrane contact sites. In this review, cadmium effects on organellar structure and function will be critically discussed with particular consideration to disruption of organelle physiology in vertebrates.
Collapse
|
14
|
Busch KB. Inner mitochondrial membrane compartmentalization: Dynamics across scales. Int J Biochem Cell Biol 2020; 120:105694. [DOI: 10.1016/j.biocel.2020.105694] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/23/2019] [Accepted: 01/09/2020] [Indexed: 01/08/2023]
|
15
|
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: 1.6] [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'.
Collapse
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
| |
Collapse
|
16
|
Madreiter-Sokolowski CT, Ramadani-Muja J, Ziomek G, Burgstaller S, Bischof H, Koshenov Z, Gottschalk B, Malli R, Graier WF. Tracking intra- and inter-organelle signaling of mitochondria. FEBS J 2019; 286:4378-4401. [PMID: 31661602 PMCID: PMC6899612 DOI: 10.1111/febs.15103] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/19/2019] [Accepted: 10/22/2019] [Indexed: 12/15/2022]
Abstract
Mitochondria are as highly specialized organelles and masters of the cellular energy metabolism in a constant and dynamic interplay with their cellular environment, providing adenosine triphosphate, buffering Ca2+ and fundamentally contributing to various signaling pathways. Hence, such broad field of action within eukaryotic cells requires a high level of structural and functional adaptation. Therefore, mitochondria are constantly moving and undergoing fusion and fission processes, changing their shape and their interaction with other organelles. Moreover, mitochondrial activity gets fine-tuned by intra- and interorganelle H+ , K+ , Na+ , and Ca2+ signaling. In this review, we provide an up-to-date overview on mitochondrial strategies to adapt and respond to, as well as affect, their cellular environment. We also present cutting-edge technologies used to track and investigate subcellular signaling, essential to the understanding of various physiological and pathophysiological processes.
Collapse
Affiliation(s)
- Corina T Madreiter-Sokolowski
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria.,Department of Health Sciences and Technology, ETH Zurich, Schwerzenbach, Switzerland
| | - Jeta Ramadani-Muja
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Gabriela Ziomek
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Sandra Burgstaller
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Helmut Bischof
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Zhanat Koshenov
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Benjamin Gottschalk
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Roland Malli
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria.,BioTechMed, Graz, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria.,BioTechMed, Graz, Austria
| |
Collapse
|
17
|
Gottschalk B, Klec C, Leitinger G, Bernhart E, Rost R, Bischof H, Madreiter-Sokolowski CT, Radulović S, Eroglu E, Sattler W, Waldeck-Weiermair M, Malli R, Graier WF. MICU1 controls cristae junction and spatially anchors mitochondrial Ca 2+ uniporter complex. Nat Commun 2019; 10:3732. [PMID: 31427612 PMCID: PMC6700202 DOI: 10.1038/s41467-019-11692-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 07/30/2019] [Indexed: 12/15/2022] Open
Abstract
Recently identified core proteins (MICU1, MCU, EMRE) forming the mitochondrial Ca2+ uniporter complex propelled investigations into its physiological workings. Here, we apply structured illumination microscopy to visualize and localize these proteins in living cells. Our data show that MICU1 localizes at the inner boundary membrane (IBM) due to electrostatic interaction of its polybasic domain. Moreover, this exclusive localization of MICU1 is important for the stability of cristae junctions (CJ), cytochrome c release and mitochondrial membrane potential. In contrast to MICU1, MCU and EMRE are homogeneously distributed at the inner mitochondrial membrane under resting conditions. However, upon Ca2+ elevation MCU and EMRE dynamically accumulate at the IBM in a MICU1-dependent manner. Eventually, our findings unveil an essential function of MICU1 in CJ stabilization and provide mechanistic insights of how sophistically MICU1 controls the MCU-Complex while maintaining the structural mitochondrial membrane framework.
Collapse
Affiliation(s)
- Benjamin Gottschalk
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Christiane Klec
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Gerd Leitinger
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Cell Biology, Histology and Embryology, Medical University of Graz, Neue Stiftingtalstraße 6/2, 8010 Graz, Austria
| | - Eva Bernhart
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - René Rost
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Helmut Bischof
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Corina T. Madreiter-Sokolowski
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Snježana Radulović
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria ,0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Cell Biology, Histology and Embryology, Medical University of Graz, Neue Stiftingtalstraße 6/2, 8010 Graz, Austria
| | - Emrah Eroglu
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Wolfgang Sattler
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria ,grid.452216.6BioTechMed Graz, Mozartgasse 12/2, Graz, 8010 Austria
| | - Markus Waldeck-Weiermair
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Roland Malli
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria ,grid.452216.6BioTechMed Graz, Mozartgasse 12/2, Graz, 8010 Austria
| | - Wolfgang F. Graier
- 0000 0000 8988 2476grid.11598.34Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria ,grid.452216.6BioTechMed Graz, Mozartgasse 12/2, Graz, 8010 Austria
| |
Collapse
|
18
|
|
19
|
Abstract
Significance: In addition to their classical role in cellular ATP production, mitochondria are of key relevance in various (patho)physiological mechanisms including second messenger signaling, neuro-transduction, immune responses and death induction. Recent Advances: Within cells, mitochondria are motile and display temporal changes in internal and external structure ("mitochondrial dynamics"). During the last decade, substantial empirical and in silico evidence was presented demonstrating that mitochondrial dynamics impacts on mitochondrial function and vice versa. Critical Issues: However, a comprehensive and quantitative understanding of the bidirectional links between mitochondrial external shape, internal structure and function ("morphofunction") is still lacking. The latter particularly hampers our understanding of the functional properties and behavior of individual mitochondrial within single living cells. Future Directions: In this review we discuss the concept of mitochondrial morphofunction in mammalian cells, primarily using experimental evidence obtained within the last decade. The topic is introduced by briefly presenting the central role of mitochondria in cell physiology and the importance of the mitochondrial electron transport chain (ETC) therein. Next, we summarize in detail how mitochondrial (ultra)structure is controlled and discuss empirical evidence regarding the equivalence of mitochondrial (ultra)structure and function. Finally, we provide a brief summary of how mitochondrial morphofunction can be quantified at the level of single cells and mitochondria, how mitochondrial ultrastructure/volume impacts on mitochondrial bioreactions and intramitochondrial protein diffusion, and how mitochondrial morphofunction can be targeted by small molecules.
Collapse
Affiliation(s)
- Elianne P. Bulthuis
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Merel J.W. Adjobo-Hermans
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Peter H.G.M. Willems
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Werner J.H. Koopman
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
- Address correspondence to: Dr. Werner J.H. Koopman, Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, P.O. Box 9101, Nijmegen NL-6500 HB, The Netherlands
| |
Collapse
|
20
|
Pohl EE, Rupprecht A, Macher G, Hilse KE. Important Trends in UCP3 Investigation. Front Physiol 2019; 10:470. [PMID: 31133866 PMCID: PMC6524716 DOI: 10.3389/fphys.2019.00470] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 04/04/2019] [Indexed: 11/13/2022] Open
Abstract
Membrane uncoupling protein 3 (UCP3), a member of the mitochondrial uncoupling protein family, was discovered in 1997. UCP3's properties, such as its high homology to other mitochondrial carriers, especially to UCP2, its short lifetime and low specificity of UCP3 antibodies, have hindered progress in understanding its biological function and transport mechanism over decades. The abundance of UCP3 is highest in murine brown adipose tissue (BAT, 15.0 pmol/mg protein), compared to heart (2.7 pmol/mg protein) and the gastrocnemius muscle (1.7 pmol/mg protein), but it is still 400-fold lower than the abundance of UCP1, a biomarker for BAT. Investigation of UCP3 reconstituted in planar bilayer membranes revealed that it transports protons only when activated by fatty acids (FA). Although purine nucleotides (PN) inhibit UCP3-mediated transport, the molecular mechanism differs from that of UCP1. It remains a conundrum that two homologous proton-transporting proteins exist within the same tissue. Recently, we proposed that UCP3 abundance directly correlates with the degree of FA β-oxidation in cell metabolism. Further development in this field implies that UCP3 may have dual function in transporting substrates, which have yet to be identified, alongside protons. Evaluation of the literature with respect to UCP3 is a complex task because (i) UCP3 features are often extrapolated from its "twin" UCP2 without additional proof, and (ii) the specificity of antibodies against UCP3 used in studies is rarely evaluated. In this review, we primarily focus on recent findings obtained for UCP3 in biological and biomimetic systems.
Collapse
Affiliation(s)
- Elena E. Pohl
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
- Institute of Pharmacology and Toxicology, Rostock University Medical Center, Rostock, Germany
| | - Gabriel Macher
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Karolina E. Hilse
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| |
Collapse
|
21
|
Rupprecht A, Moldzio R, Mödl B, Pohl EE. Glutamine regulates mitochondrial uncoupling protein 2 to promote glutaminolysis in neuroblastoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:391-401. [PMID: 30885735 DOI: 10.1016/j.bbabio.2019.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 12/30/2018] [Accepted: 03/14/2019] [Indexed: 01/26/2023]
Abstract
Mitochondrial uncoupling protein 2 (UCP2) is highly abundant in rapidly proliferating cells that utilize aerobic glycolysis, such as stem cells, cancer cells, and cells of the immune system. However, the function of UCP2 has been a longstanding conundrum. Considering the strict regulation and unusually short life time of the protein, we propose that UCP2 acts as a "signaling protein" under nutrient shortage in cancer cells. We reveal that glutamine shortage induces the rapid and reversible downregulation of UCP2, decrease of the metabolic activity and proliferation of neuroblastoma cells, that are regulated by glutamine per se but not by glutamine metabolism. Our findings indicate a very rapid (within 1 h) metabolic adaptation that allows the cell to survive by either shifting its metabolism to the use of the alternative fuel glutamine or going into a reversible, more quiescent state. The results imply that UCP2 facilitates glutamine utilization as an energetic fuel source, thereby providing metabolic flexibility during glucose shortage. The targeting UCP2 by drugs to intervene with cancer cell metabolism may represent a new strategy for treatment of cancers resistant to other therapies.
Collapse
Affiliation(s)
- Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria; Institute of Pharmacology and Toxicology, Rostock University Medical Center, Germany.
| | - Rudolf Moldzio
- Institute of Medical Biochemistry, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Bernadette Mödl
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Elena E Pohl
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria.
| |
Collapse
|
22
|
Ježek P, Jabůrek M, Porter RK. Uncoupling mechanism and redox regulation of mitochondrial uncoupling protein 1 (UCP1). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:259-269. [DOI: 10.1016/j.bbabio.2018.11.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/15/2018] [Accepted: 11/07/2018] [Indexed: 01/11/2023]
|
23
|
Yan Q, Cai M, Zhou L, Xu H, Shi Y, Sun J, Jiang J, Gao J, Wang H. Using an RNA aptamer probe for super-resolution imaging of native EGFR. NANOSCALE ADVANCES 2019; 1:291-298. [PMID: 36132464 PMCID: PMC9473275 DOI: 10.1039/c8na00143j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 01/08/2019] [Accepted: 08/16/2018] [Indexed: 05/06/2023]
Abstract
Aptamers, referred to as "chemical antibodies", are short single-stranded oligonucleotides that bind to targets with high affinity and specificity. Compared with antibodies, aptamers can be designed, developed and modified easily. Since their discovery, aptamers have been widely used in in vitro diagnostics and molecular imaging. However, they are relatively less studied and applied in advanced microscopy. Here we used an RNA aptamer in dSTORM imaging and obtained a high-quality image of EGFR nanoscale clusters on live cell membranes. The results showed that the cluster number and size with aptamer labeling were almost the same as those with labeling with the natural ligand EGF, but the morphology of the clusters was smaller and more regular than that with cetuximab labeling. Meanwhile, dual-color imaging demonstrated sufficient fluorophore labeling, highly specific recognition and greatly accurate clustering information provided by aptamers. Furthermore, the aptamer labeling method indicated that active EGFR formed larger clusters containing more molecules than resting EGFR, which was hidden under the antibody labeling. Our work suggested that aptamers can be used as versatile probes in super-resolution imaging with small steric hindrance, opening a new avenue for detailed and precise morphological analysis of membrane proteins.
Collapse
Affiliation(s)
- Qiuyan Yan
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Mingjun Cai
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
| | - Lulu Zhou
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Haijiao Xu
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Yan Shi
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
| | - Jiayin Sun
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
| | - Junguang Jiang
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
| | - Jing Gao
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
| | - Hongda Wang
- State Key Laboratory of Electroanalytical Chemistry, Research Center of Biomembranomics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun Jilin 130022 P. R. China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology Wenhai Road, Aoshanwei, Jimo, Qingdao Shandong 266237 P. R. China
| |
Collapse
|
24
|
Alpár A, Harkany T. Novel insights into the spatial and temporal complexity of hypothalamic organization through precision methods allowing nanoscale resolution. J Intern Med 2018; 284:568-580. [PMID: 30027599 DOI: 10.1111/joim.12815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The mammalian hypothalamus contains an astounding heterogeneity of neurons to achieve its role in coordinating central responses to virtually any environmental stressor over the life-span of an individual. Therefore, while core features of intrahypothalamic neuronal modalities and wiring patterns are stable during vertebrate evolution, integration of the hypothalamus into hierarchical brain-wide networks evolved to coordinate its output with emotionality, cognition and conscious decision-making. The advent of single-cell technologies represents a recent milestone in the study of hypothalamic organization by allowing the dissection of cellular heterogeneity and establishing causality between opto- and chemogenetic activity modulation of molecularly-resolved neuronal contingents and specific behaviours. Thus, organizational rules to accumulate an unprecedented variety of hierarchical neuroendocrine command networks into a minimal brain volume are being unravelled. Here, we review recent understanding at nanoscale resolution on how neuronal heterogeneity in the mammalian hypothalamus underpins the diversification of hormonal and synaptic output and keeps those sufficiently labile for continuous adaptation to meet environmental demands. Particular emphasis is directed towards the dissection of neuronal circuitry for aggression and food intake. Mechanistic data encompass cell identities, synaptic connectivity within and outside the hypothalamus to link vegetative and conscious levels of innate behaviours, and context- and circadian rhythm-dependent rules of synaptic neurophysiology to distinguish hypothalamic foci that either tune the body's metabolic set-point or specify behaviours. Consequently, novel insights emerge to explain the evolutionary advantages of non-laminar organization for neuroendocrine circuits coincidently using fast neurotransmitters and neuropeptides. These are then accrued into novel therapeutic principles that meet therapeutic criteria for human metabolic diseases.
Collapse
Affiliation(s)
- A Alpár
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Semmelweis University, Budapest, Hungary.,Department of Anatomy, Histology, and Embryology, Semmelweis University, Budapest, Hungary
| | - T Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria.,Department of Neuroscience, Karolinska Institutet, Solna, Sweden
| |
Collapse
|
25
|
Hilse KE, Rupprecht A, Egerbacher M, Bardakji S, Zimmermann L, Wulczyn AEMS, Pohl EE. The Expression of Uncoupling Protein 3 Coincides With the Fatty Acid Oxidation Type of Metabolism in Adult Murine Heart. Front Physiol 2018; 9:747. [PMID: 29988383 PMCID: PMC6024016 DOI: 10.3389/fphys.2018.00747] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 05/28/2018] [Indexed: 01/07/2023] Open
Abstract
The involvement of mitochondrial uncoupling proteins 2 and 3 in the pathogenesis of cardiovascular diseases is widely acknowledged. However, contradictory reports show that the functions of UCP2/UCP3 are still disputed. We have previously described that UCP2 is highly abundant in cells that rely on glycolysis, such as stem, cancer and activated immune cells. In contrast, high amounts of UCP3 are present in brown adipose tissue, followed by heart and skeletal muscles - all known to metabolize fatty acids (FA) to a high extent. Using two different models - mouse embryonic stem cell (mESC) differentiation to cardiomyocytes (CM) and murine heart at different developmental stages - we now tested the concept that the expression ratio between UCP2 and UCP3 indicates the metabolism type in CM. Our results revealed the tight correlation between UCP3 abundance, expression of mitochondrial fatty acid oxidation (FAO) markers and presence of multiple connections between mitochondria and lipid droplets. We further demonstrated that the time course of UCP3 expression neither coincided with the onset of the electrical activity in CM, derived from mESC, nor with the expression of respiratory chain proteins, the observation which rendered protein participation in ROS regulation unlikely. The present data imply that UCP3 may facilitate FAO by transporting FAs into mitochondria. In contrast, UCP2 was highly abundant at early stages of heart development and in mESC. Understanding, that the expression patterns of UCP3 and UCP2 in heart during development reflect the type of the cell metabolism is key to the uncovering their different functions. Their expression ratio may be an important diagnostic criterion for the degree of CM differentiation and/or severity of a heart failure.
Collapse
Affiliation(s)
- Karolina E Hilse
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Anne Rupprecht
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Monika Egerbacher
- Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Sarah Bardakji
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Lars Zimmermann
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Andrea E M Seiler Wulczyn
- German Centre for the Protection of Laboratory Animals (Bf3R), Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Elena E Pohl
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Vienna, Austria
| |
Collapse
|
26
|
Gottschalk B, Klec C, Waldeck-Weiermair M, Malli R, Graier WF. Intracellular Ca 2+ release decelerates mitochondrial cristae dynamics within the junctions to the endoplasmic reticulum. Pflugers Arch 2018. [PMID: 29527615 PMCID: PMC6047742 DOI: 10.1007/s00424-018-2133-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mitochondria are multifunctional organelles that essentially contribute to cell signaling by sophisticated mechanisms of communications. Live cell imaging studies showed that mitochondria are dynamic and complex structures that form ramified networks by directed movements, fission, and fusion events. There is emerging evidence that the morphology of mitochondria determines cellular functions and vice versa. Several intracellular signaling pathways and messengers including Ca2+ dynamically influence the architecture of mitochondria. Because electron microscopy cannot be utilized for an assessment of dynamics of mitochondrial morphology in intact cells, most studies were performed using wide-field or laser confocal fluorescence microscopies that, due to limitations of their spatial resolution, do not allow investigating sub-mitochondrial structures. Accordingly, our understanding of the dynamics of substructures of mitochondria is quite limited. Here, we present a robust super-resolution method to quantify the dynamics of mitochondrial cristae, the main substructures of the inner mitochondrial membrane, exploiting structured illumination microscopy (SIM). We observed that knockdown of the dynamin-like 120-kDa protein, which is encoded by the OPA1 gene, specifically reduces the dynamics of the mitochondrial cristae membranes (CM), while the inner boundary membrane (IBM) remained flexible. We further used dual color SIM to quantify the dynamics of CM in the junction between mitochondria and the endoplasmic reticulum (ER; mitochondrial associated membranes, MAMs). Intracellular Ca2+ release spatially reduced CM-dynamics in MAMs. Moreover, CM-dynamics was independent from matrix Ca2+ signal. Our data suggest that local Ca2+ signals specifically control CM-dynamics and structure to facilitate a well-balanced functional (Ca2+) interplay between mitochondria and the ER.
Collapse
Affiliation(s)
- Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria
| | - Christinae Klec
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria
| | - Markus Waldeck-Weiermair
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria
- BioTechMed, Graz, Austria
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010, Graz, Austria.
- BioTechMed, Graz, Austria.
| |
Collapse
|
27
|
Kahancová A, Sklenář F, Ježek P, Dlasková A. Regulation of glucose-stimulated insulin secretion by ATPase Inhibitory Factor 1 (IF1). FEBS Lett 2018; 592:999-1009. [PMID: 29380352 DOI: 10.1002/1873-3468.12991] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/16/2018] [Accepted: 01/22/2018] [Indexed: 12/13/2022]
Abstract
ATPase Inhibitory factor 1 (IF1) is an endogenous regulator of mitochondrial ATP synthase, which is involved in cellular metabolism. Although great progress has been made, biological roles of IF1 and molecular mechanisms of its action are still to be elucidated. Here, we show that IF1 is present in pancreatic β-cells, bound to the ATP synthase also under normal physiological conditions. IF1 silencing in model pancreatic β-cells (INS-1E) increases insulin secretion over a range of glucose concentrations. The left-shifted dose-response curve reveals excessive insulin secretion even under low glucose, corresponding to fasting conditions. A parallel increase in cellular respiration and ATP levels is observed. To conclude, our results indicate that IF1 is a negative regulator of insulin secretion involved in pancreatic β-cell glucose sensing.
Collapse
Affiliation(s)
- Anežka Kahancová
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Filip Sklenář
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Andrea Dlasková
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| |
Collapse
|
28
|
Transitional correlation between inner-membrane potential and ATP levels of neuronal mitochondria. Sci Rep 2018; 8:2993. [PMID: 29445117 PMCID: PMC5813116 DOI: 10.1038/s41598-018-21109-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/30/2018] [Indexed: 12/11/2022] Open
Abstract
The importance of highly active mitochondria and their contribution to neuronal function has been of recent interest. In most cases, however, mitochondrial activity is estimated using measurements of mitochondrial inner membrane potential (IMPmito), and little is known about the dynamics of native mitochondrial ATP (ATPmito). This study conducted simultaneous imaging of IMPmito and ATPmito in neurons to explore their behaviour and their correlation during physiological mitochondrial/neuronal activity. We found that mitochondrial size, transport velocity and transport direction are not dependent on ATPmito or IMPmito. However, changes in ATPmito and IMPmito during mitochondrial fission/fusion were found; IMPmito depolarized via mitochondrial fission and hyperpolarized via fusion, and ATPmito levels increased after fusion. Because the density of mitochondria is higher in growth cones (GCs) than in axonal processes, integrated ATPmito signals (density × ATPmito) were higher in GCs. This integrated signal in GCs correlated with axonal elongation. However, while the averaged IMPmito was relatively hyperpolarized in GCs, there was no correlation between IMPmito in GCs and axonal elongation. A detailed time-course analysis performed to clarify the reason for these discrepancies showed that IMPmito and ATPmito levels did not always correlate accurately; rather, there were several correlation patterns that changed over time.
Collapse
|
29
|
The Stress-Induced Transcription Factor NR4A1 Adjusts Mitochondrial Function and Synapse Number in Prefrontal Cortex. J Neurosci 2018; 38:1335-1350. [PMID: 29295823 PMCID: PMC5815341 DOI: 10.1523/jneurosci.2793-17.2017] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/10/2017] [Accepted: 12/08/2017] [Indexed: 12/28/2022] Open
Abstract
The energetic costs of behavioral chronic stress are unlikely to be sustainable without neuronal plasticity. Mitochondria have the capacity to handle synaptic activity up to a limit before energetic depletion occurs. Protective mechanisms driven by the induction of neuronal genes likely evolved to buffer the consequences of chronic stress on excitatory neurons in prefrontal cortex (PFC), as this circuitry is vulnerable to excitotoxic insults. Little is known about the genes involved in mitochondrial adaptation to the buildup of chronic stress. Using combinations of genetic manipulations and stress for analyzing structural, transcriptional, mitochondrial, and behavioral outcomes, we characterized NR4A1 as a stress-inducible modifier of mitochondrial energetic competence and dendritic spine number in PFC. NR4A1 acted as a transcription factor for changing the expression of target genes previously involved in mitochondrial uncoupling, AMP-activated protein kinase activation, and synaptic growth. Maintenance of NR4A1 activity by chronic stress played a critical role in the regressive synaptic organization in PFC of mouse models of stress (male only). Knockdown, dominant-negative approach, and knockout of Nr4a1 in mice and rats (male only) protected pyramidal neurons against the adverse effects of chronic stress. In human PFC tissues of men and women, high levels of the transcriptionally active NR4A1 correlated with measures of synaptic loss and cognitive impairment. In the context of chronic stress, prolonged expression and activity of NR4A1 may lead to responses of mitochondria and synaptic connectivity that do not match environmental demand, resulting in circuit malfunction between PFC and other brain regions, constituting a pathological feature across disorders. SIGNIFICANCE STATEMENT The bioenergetic cost of chronic stress is too high to be sustainable by pyramidal prefrontal neurons. Cellular checkpoints have evolved to adjust the responses of mitochondria and synapses to the buildup of chronic stress. NR4A1 plays such a role by controlling the energetic competence of mitochondria with respect to synapse number. As an immediate-early gene, Nr4a1 promotes neuronal plasticity, but sustained expression or activity can be detrimental. NR4A1 expression and activity is sustained by chronic stress in animal models and in human studies of neuropathologies sensitive to the buildup of chronic stress. Therefore, antagonism of NR4A1 is a promising avenue for preventing the regressive synaptic reorganization in cortical systems in the context of chronic stress.
Collapse
|
30
|
Burke PJ. Mitochondria, Bioenergetics and Apoptosis in Cancer. Trends Cancer 2017; 3:857-870. [PMID: 29198441 PMCID: PMC5957506 DOI: 10.1016/j.trecan.2017.10.006] [Citation(s) in RCA: 259] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 10/12/2017] [Accepted: 10/19/2017] [Indexed: 10/18/2022]
Abstract
Until recently, the dual roles of mitochondria in ATP production (bioenergetics) and apoptosis (cell life/death decision) were thought to be separate. New evidence points to a more intimate link between these two functions, mediated by the remodeling of the mitochondrial ultrastructure during apoptosis. While most of the key molecular players that regulate this process have been identified (primarily membrane proteins), the exact mechanisms by which they function are not yet understood. Because resistance to apoptosis is a hallmark of cancer, and because ultimately all chemotherapies are believed to result directly or indirectly in induction of apoptosis, a better understanding of the biophysical processes involved may lead to new avenues for therapy.
Collapse
Affiliation(s)
- Peter J Burke
- Department of Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA, USA; Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA, USA; Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA.
| |
Collapse
|
31
|
Schwarzländer M, Fuchs P. Plant mitochondrial membranes: adding structure and new functions to respiratory physiology. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:147-157. [PMID: 28992511 DOI: 10.1016/j.pbi.2017.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/31/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
The membranes of mitochondria are focal points of cellular physiology and respiratory energy transformation. Recent discoveries have started painting a refined picture of plant mitochondrial membranes as platforms in which structure and function have evolved in an interconnected and dynamically regulated manner. Hosting ancillary functions that interact with other mitochondrial properties gives mitochondria the characteristics of multitasking and integrated molecular mega machines. We review recent insights into the makeup and the plasticity of the outer and inner mitochondrial membranes, their intimate relationship with respiratory function and regulation, and their properties in mediating solute transport. Synthesizing recent research advances we hypothesize that plant mitochondrial membranes are a privileged location for incorporation of a wide range of processes, some of which collaborate with respiratory function, including plant immunity, metabolic regulation and signal transduction, to underpin flexibility in the acclimation to changing environments.
Collapse
Affiliation(s)
- Markus Schwarzländer
- Institute of Crop Science and Resource Conservation (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, Friedrich-Ebert-Allee 144, D-53113 Bonn, Germany; Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, D-48143 Münster, Germany.
| | - Philippe Fuchs
- Institute of Crop Science and Resource Conservation (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, Friedrich-Ebert-Allee 144, D-53113 Bonn, Germany; Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, D-48143 Münster, Germany
| |
Collapse
|
32
|
Wang X, Zhang X, Wu D, Huang Z, Hou T, Jian C, Yu P, Lu F, Zhang R, Sun T, Li J, Qi W, Wang Y, Gao F, Cheng H. Mitochondrial flashes regulate ATP homeostasis in the heart. eLife 2017; 6. [PMID: 28692422 PMCID: PMC5503511 DOI: 10.7554/elife.23908] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 05/16/2017] [Indexed: 01/01/2023] Open
Abstract
The maintenance of a constant ATP level (‘set-point’) is a vital homeostatic function shared by eukaryotic cells. In particular, mammalian myocardium exquisitely safeguards its ATP set-point despite 10-fold fluctuations in cardiac workload. However, the exact mechanisms underlying this regulation of ATP homeostasis remain elusive. Here we show mitochondrial flashes (mitoflashes), recently discovered dynamic activity of mitochondria, play an essential role for the auto-regulation of ATP set-point in the heart. Specifically, mitoflashes negatively regulate ATP production in isolated respiring mitochondria and, their activity waxes and wanes to counteract the ATP supply-demand imbalance caused by superfluous substrate and altered workload in cardiomyocytes. Moreover, manipulating mitoflash activity is sufficient to inversely shift the otherwise stable ATP set-point. Mechanistically, the Bcl-xL-regulated proton leakage through F1Fo-ATP synthase appears to mediate the coupling between mitoflash production and ATP set-point regulation. These findings indicate mitoflashes appear to constitute a digital auto-regulator for ATP homeostasis in the heart. DOI:http://dx.doi.org/10.7554/eLife.23908.001 A small molecule called ATP is often referred to as the primary “energy currency” of living cells. It is required to power tasks as diverse as the general housekeeping processes that keep all cells alive to the programmed cell death response that dismantles any cells that are no longer needed. It is also crucial that cells maintain a constant level of ATP at all times, even when the supply of and demand for ATP fluctuate. This control is particularly important in the mammalian heart where the rates of ATP production and consumption change ten-fold during intense exercise. Despite intensive research over the past decades, it was still not known how cells keep ATP levels constant. In many cell types, including heart muscle cells, ATP is mainly produced inside compartments called mitochondria. Each heart muscle cell contains between 5,000 and 8,000 mitochondria. Recent experiments have shown that ATP production in mitochondria is interrupted by ten-second bursts called “mitochondrial flashes” (or mitoflashes for short), during which the mitochondria release chemicals called reactive oxygen species. The mitoflashes are tightly linked with energy usage, and Wang, Zhang, Wu et al. have now explored if and how mitoflashes regulate ATP levels in the heart. Experiments on isolated mitochondria from mouse heart muscle cells showed that mitoflashes inhibit the production of ATP. When the intact heart muscle cells were given excess of the building blocks needed to produce ATP – mitoflashes occurred more often. Conversely, when the cells were forced to contract more quickly, which increased demand for ATP, the mitoflashes occurred less often. Importantly, the level of ATP inside the cells actually remained constant in the experiments. Furthermore, inhibiting mitoflashes with antioxidants increased the ATP concentration in heart muscle cells. Lastly, Wang et al. demonstrated that mitoflashes could be triggered under certain conditions. Overall, these experiments uncovered a way in which highly active cells can maintain a constant level of ATP. Future studies are needed to understand exactly how mitoflashes are initiated and how they in turn inhibit ATP production. A better understanding of these processes might uncover molecules that could be targeted by drugs to the control of the rate of ATP production to treat heart failure. DOI:http://dx.doi.org/10.7554/eLife.23908.002
Collapse
Affiliation(s)
- Xianhua Wang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Xing Zhang
- Department of Aerospace Medicine, The Fourth Military Medical University, Xi'an, China
| | - Di Wu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Zhanglong Huang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Tingting Hou
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Chongshu Jian
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Peng Yu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Fujian Lu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Rufeng Zhang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Tao Sun
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Jinghang Li
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Wenfeng Qi
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Yanru Wang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Feng Gao
- Department of Aerospace Medicine, The Fourth Military Medical University, Xi'an, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| |
Collapse
|
33
|
Weichselbaum E, Österbauer M, Knyazev DG, Batishchev OV, Akimov SA, Hai Nguyen T, Zhang C, Knör G, Agmon N, Carloni P, Pohl P. Origin of proton affinity to membrane/water interfaces. Sci Rep 2017; 7:4553. [PMID: 28674402 PMCID: PMC5495794 DOI: 10.1038/s41598-017-04675-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 05/18/2017] [Indexed: 11/21/2022] Open
Abstract
Proton diffusion along biological membranes is vitally important for cellular energetics. Here we extended previous time-resolved fluorescence measurements to study the time and temperature dependence of surface proton transport. We determined the Gibbs activation energy barrier ΔG ‡r that opposes proton surface-to-bulk release from Arrhenius plots of (i) protons' surface diffusion constant and (ii) the rate coefficient for proton surface-to-bulk release. The large size of ΔG ‡r disproves that quasi-equilibrium exists in our experiments between protons in the near-membrane layers and in the aqueous bulk. Instead, non-equilibrium kinetics describes the proton travel between the site of its photo-release and its arrival at a distant membrane patch at different temperatures. ΔG ‡r contains only a minor enthalpic contribution that roughly corresponds to the breakage of a single hydrogen bond. Thus, our experiments reveal an entropic trap that ensures channeling of highly mobile protons along the membrane interface in the absence of potent acceptors.
Collapse
Affiliation(s)
- Ewald Weichselbaum
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Maria Österbauer
- 0000 0001 1941 5140grid.9970.7Institute of Inorganic Chemistry, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Denis G. Knyazev
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Oleg V. Batishchev
- 0000 0001 2192 9124grid.4886.2A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskiy pr. 31/4, Moscow, 119071 Russian Federation ,0000000092721542grid.18763.3bMoscow Institute of Physics and Technology, Institutsky lane, 9, 141700 Dolgoprudniy, Russian Federation
| | - Sergey A. Akimov
- 0000 0001 2192 9124grid.4886.2A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskiy pr. 31/4, Moscow, 119071 Russian Federation ,0000 0001 0010 3972grid.35043.31National University of Science and Technology “MISiS”, Leninskiy pr. 4, Moscow, 119991 Russian Federation
| | - Trung Hai Nguyen
- 0000 0001 0728 696Xgrid.1957.aComputational Biomedicine (IAS-5 / INM-9) Forschungszentrum Jülich, 52425 Jülich, Germany, RWTH Aachen University, 52056 Aachen, Germany
| | - Chao Zhang
- 0000 0001 0728 696Xgrid.1957.aComputational Biomedicine (IAS-5 / INM-9) Forschungszentrum Jülich, 52425 Jülich, Germany, RWTH Aachen University, 52056 Aachen, Germany ,0000000121885934grid.5335.0Department of Chemistry, University of Cambridge, Lensfield Rd, Cambridge, CB2 1EW United Kingdom
| | - Günther Knör
- 0000 0001 1941 5140grid.9970.7Institute of Inorganic Chemistry, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Noam Agmon
- 0000 0004 1937 0538grid.9619.7Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401 Israel
| | - Paolo Carloni
- 0000 0001 0728 696Xgrid.1957.aComputational Biomedicine (IAS-5 / INM-9) Forschungszentrum Jülich, 52425 Jülich, Germany, RWTH Aachen University, 52056 Aachen, Germany
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, 4040, Linz, Austria.
| |
Collapse
|
34
|
Karner A, Nimmervoll B, Plochberger B, Klotzsch E, Horner A, Knyazev DG, Kuttner R, Winkler K, Winter L, Siligan C, Ollinger N, Pohl P, Preiner J. Tuning membrane protein mobility by confinement into nanodomains. NATURE NANOTECHNOLOGY 2017; 12:260-266. [PMID: 27842062 PMCID: PMC5734611 DOI: 10.1038/nnano.2016.236] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 09/30/2016] [Indexed: 05/04/2023]
Abstract
High-speed atomic force microscopy (HS-AFM) can be used to visualize function-related conformational changes of single soluble proteins. Similar studies of single membrane proteins are, however, hampered by a lack of suitable flat, non-interacting membrane supports and by high protein mobility. Here we show that streptavidin crystals grown on mica-supported lipid bilayers can be used as porous supports for membranes containing biotinylated lipids. Using SecYEG (protein translocation channel) and GlpF (aquaglyceroporin), we demonstrate that the platform can be used to tune the lateral mobility of transmembrane proteins to any value within the dynamic range accessible to HS-AFM imaging through glutaraldehyde-cross-linking of the streptavidin. This allows HS-AFM to study the conformation or docking of spatially confined proteins, which we illustrate by imaging GlpF at sub-molecular resolution and by observing the motor protein SecA binding to SecYEG.
Collapse
Affiliation(s)
- Andreas Karner
- Center for Advanced Bioanalysis GmbH, Gruberstr. 40-42, 4020 Linz, Austria
| | | | - Birgit Plochberger
- Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020 Linz, Austria
| | - Enrico Klotzsch
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia
| | - Andreas Horner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Denis G. Knyazev
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Roland Kuttner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Klemens Winkler
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Lukas Winter
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Christine Siligan
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Nicole Ollinger
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
| | - Johannes Preiner
- Center for Advanced Bioanalysis GmbH, Gruberstr. 40-42, 4020 Linz, Austria
| |
Collapse
|
35
|
Smorodchenko A, Schneider S, Rupprecht A, Hilse K, Sasgary S, Zeitz U, Erben RG, Pohl EE. UCP2 up-regulation within the course of autoimmune encephalomyelitis correlates with T-lymphocyte activation. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1002-1012. [PMID: 28130201 DOI: 10.1016/j.bbadis.2017.01.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 01/07/2017] [Accepted: 01/23/2017] [Indexed: 01/20/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating autoimmune disorder of the central nervous system (CNS) associated with severe neurological disability. Reactive oxygen species (ROS) and mitochondrial dysfunction play a pivotal role in the pathogenesis of this disease. Several members of the mitochondrial uncoupling protein subfamily (UCP2-UCP5) were suggested to regulate ROS by diminishing the mitochondrial membrane potential and constitute therefore a promising pharmacological target for MS. To evaluate the role of different uncoupling proteins in neuroinflammation, we have investigated their expression patterns in murine brain and spinal cord (SC) during different stages of experimental autoimmune encephalomyelitis (EAE), an animal model for MS. At mRNA and protein levels we found that only UCP2 is up-regulated in the SC, but not in brain. The increase in UCP2 expression was antigen-independent, reached its maximum between 14 and 21days in both OVA and MOG immunized animals and correlated with an augmented number of CD3+ T-lymphocytes in SC parenchyma. The decrease in abundance of UCP4 was due to neuronal injury and was only detected in CNS of MOG-induced EAE animals. The results provide evidence that the involvement of mitochondrial UCP2 in CNS inflammation during EAE may be mainly explained by the invasion of activated T-lymphocytes. This conclusion coincides with our previous observation that UCP2 is up-regulated in activated and rapidly proliferating T-cells and participates in fast metabolic re-programming of cells during proliferation.
Collapse
Affiliation(s)
- Alina Smorodchenko
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria; Institute of Vegetative Anatomy, Charité - Universitätsmedizin Berlin, Germany.
| | - Stephanie Schneider
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Karoline Hilse
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Soleman Sasgary
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Ute Zeitz
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Reinhold G Erben
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Elena E Pohl
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria.
| |
Collapse
|
36
|
Das A, Nag S, Mason AB, Barroso MM. Endosome-mitochondria interactions are modulated by iron release from transferrin. J Cell Biol 2016; 214:831-45. [PMID: 27646275 PMCID: PMC5037410 DOI: 10.1083/jcb.201602069] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 08/11/2016] [Indexed: 12/21/2022] Open
Abstract
Using superresolution and quantitative fluorescence microscopy, Das et al. have revealed that iron-transferrin–containing endosomes directly interact with mitochondria, facilitating iron transfer in epithelial cells. Their findings further enrich the repertoire of organelle–organelle direct interactions to accomplish a functional significance. Transient “kiss and run” interactions between endosomes containing iron-bound transferrin (Tf) and mitochondria have been shown to facilitate direct iron transfer in erythroid cells. In this study, we used superresolution three-dimensional (3D) direct stochastic optical reconstruction microscopy to show that Tf-containing endosomes directly interact with mitochondria in epithelial cells. We used live-cell time-lapse fluorescence microscopy, followed by 3D rendering, object tracking, and a distance transformation algorithm, to track Tf-endosomes and characterize the dynamics of their interactions with mitochondria. Quenching of iron sensor RDA-labeled mitochondria confirmed functional iron transfer by an interacting Tf-endosome. The motility of Tf-endosomes is significantly reduced upon interaction with mitochondria. To further assess the functional role of iron in the ability of Tf-endosomes to interact with mitochondria, we blocked endosomal iron release by using a Tf K206E/K534A mutant. Blocking intraendosomal iron release led to significantly increased motility of Tf-endosomes and increased duration of endosome–mitochondria interactions. Thus, intraendosomal iron regulates the kinetics of the interactions between Tf-containing endosomes and mitochondria in epithelial cells.
Collapse
Affiliation(s)
- Anupam Das
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208
| | - Sagarika Nag
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208
| | - Anne B Mason
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, VT 05405
| | - Margarida M Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208
| |
Collapse
|
37
|
Plecitá-Hlavatá L, Ježek P. Integration of superoxide formation and cristae morphology for mitochondrial redox signaling. Int J Biochem Cell Biol 2016; 80:31-50. [PMID: 27640755 DOI: 10.1016/j.biocel.2016.09.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 12/16/2022]
Abstract
The mitochondrial network provides the central cell's energetic and regulatory unit, which besides ATP and metabolite production participates in cellular signaling through regulated reactive oxygen species (ROS) production and various protein/ion fluxes. The inner membrane forms extensive folds, called cristae, i.e. cavities enfolded from and situated perpendicularly to its inner boundary membrane portion, which encompasses an inner cylinder within the outer membrane tubule. Mitochondrial cristae ultramorphology reflects various metabolic, physiological or pathological states. Since the mitochondrion is typically a predominant superoxide source and generated ROS also serve for the creation of information redox signals, we review known relationships between ROS generation within the respiratory chain complexes of cristae and cristae morphology. Notably, it is emphasized that cristae shape is governed by ATP-synthase dimers, MICOS complexes, OPA1 isoforms and the umbrella of their regulation, and also dependent on local protonmotive force (electrical potential component) in cristae. Cristae are also affected by redox-sensitive kinases/phosphatases or p66SHC. ATP-synthase dimers decrease in the inflated intracristal space, diminishing pH and hypothetically having minimal superoxide formation. Matrix-released signaling superoxide/H2O2 is predominantly integrated along mitochondrial tubules, whereas the diffusion of intracristal signaling ROS species is controlled by crista junctions, the widening of which enables specific retrograde redox signaling such as during hypoxic cell adaptation. Other physiological cases of H2O2 release from the mitochondrion include the modulation of insulin release in pancreatic β-cells, enhancement of insulin signaling in peripheral tissues, signaling by T-cell receptors, retrograde signaling during the cell cycle and cell differentiation, specifically that of adipocytes.
Collapse
Affiliation(s)
- Lydie Plecitá-Hlavatá
- Department of Membrane Transport Biophysics, No.75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Petr Ježek
- Department of Membrane Transport Biophysics, No.75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
| |
Collapse
|
38
|
Lo CYW, Chen S, Creed SJ, Kang M, Zhao N, Tang BZ, Elgass KD. Novel super-resolution capable mitochondrial probe, MitoRed AIE, enables assessment of real-time molecular mitochondrial dynamics. Sci Rep 2016; 6:30855. [PMID: 27492961 PMCID: PMC4974624 DOI: 10.1038/srep30855] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/08/2016] [Indexed: 12/17/2022] Open
Abstract
Mitochondria and mitochondrial dynamics play vital roles in health and disease. With the intricate nanometer-scale structure and rapid dynamics of mitochondria, super-resolution microscopy techniques possess great un-tapped potential to significantly contribute to understanding mitochondrial biology and kinetics. Here we present a novel mitochondrial probe (MitoRed AIE) suitable for live mitochondrial dynamics imaging and single particle tracking (SPT), together with a multi-dimensional data analysis approach to assess local mitochondrial (membrane) fluidity. The MitoRed AIE probe localizes primarily to mitochondrial membranes, with 95 ms fluorophore on-time delivering 106 photons/ms, characteristics which we exploit to demonstrate live cell 100 fps 3D time-lapse tracking of mitochondria. Combining our experimental and analytical approaches, we uncover mitochondrial dynamics at unprecedented time scales. This approach opens up a new regime into high spatio-temporal resolution dynamics in many areas of mitochondrial biology.
Collapse
Affiliation(s)
- Camden Yeung-Wah Lo
- Monash Micro Imaging, Monash University, Melbourne, Australia.,Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Sijie Chen
- School of Chemistry, University of Melbourne, Melbourne, Australia.,Division of Biomedical Engineering, Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, State Key Laboratory of Molecular Neuroscience and Institute of Molecular Functional Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Sarah Jayne Creed
- Monash Micro Imaging, Monash University, Melbourne, Australia.,Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Miaomiao Kang
- Division of Biomedical Engineering, Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, State Key Laboratory of Molecular Neuroscience and Institute of Molecular Functional Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Na Zhao
- School of Chemistry &Chemical Engineering, Shaanxi Normal University, P.R. China
| | - Ben Zhong Tang
- Division of Biomedical Engineering, Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, State Key Laboratory of Molecular Neuroscience and Institute of Molecular Functional Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Kirstin Diana Elgass
- Monash Micro Imaging, Monash University, Melbourne, Australia.,Hudson Institute of Medical Research, Clayton, Victoria, Australia
| |
Collapse
|
39
|
Lee CP, Millar AH. The Plant Mitochondrial Transportome: Balancing Metabolic Demands with Energetic Constraints. TRENDS IN PLANT SCIENCE 2016; 21:662-676. [PMID: 27162080 DOI: 10.1016/j.tplants.2016.04.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/25/2016] [Accepted: 04/04/2016] [Indexed: 06/05/2023]
Abstract
In plants, mitochondrial function is associated with hundreds of metabolic reactions. To facilitate these reactions, charged substrates and cofactors move across the charge-impermeable inner mitochondrial membrane via specialized transporters and must work cooperatively with the electrochemical gradient which is essential for mitochondrial function. The regulatory framework for mitochondrial metabolite transport is expected to be more complex in plants than in mammals owing to the close metabolic association between mitochondrial, plastids, and peroxisome metabolism, as well as to the major diurnal fluctuations in plant metabolic function. We propose here how recent advances can be integrated towards defining the mitochondrial transportome in plants. We also discuss what this reveals about sustaining cooperativity between bioenergetics, metabolism, and transport in typical and challenging environments.
Collapse
Affiliation(s)
- Chun Pong Lee
- Australian Reseach Council (ARC) Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
| | - A Harvey Millar
- Australian Reseach Council (ARC) Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
| |
Collapse
|
40
|
Yoshinaga MY, Kellermann MY, Valentine DL, Valentine RC. Phospholipids and glycolipids mediate proton containment and circulation along the surface of energy-transducing membranes. Prog Lipid Res 2016; 64:1-15. [PMID: 27448687 DOI: 10.1016/j.plipres.2016.07.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 05/29/2016] [Accepted: 07/13/2016] [Indexed: 01/06/2023]
Abstract
Proton bioenergetics provides the energy for growth and survival of most organisms in the biosphere ranging from unicellular marine phytoplankton to humans. Chloroplasts harvest light and generate a proton electrochemical gradient (proton motive force) that drives the production of ATP needed for carbon dioxide fixation and plant growth. Mitochondria, bacteria and archaea generate proton motive force to energize growth and other physiologies. Energy transducing membranes are at the heart of proton bioenergetics and are responsible for catalyzing the conversion of energy held in high-energy electrons→electron transport chain→proton motive force→ATP. Whereas the electron transport chain is understood in great detail there are major gaps in understanding mechanisms of proton transfer or circulation during proton bioenergetics. This paper is built on the proposition that phospho- and glyco-glycerolipids form proton transport circuitry at the membrane's surface. By this proposition, an emergent membrane property, termed the hyducton, confines active/unbound protons or hydronium ions to a region of low volume close to the membrane surface. In turn, a von Grotthuß mechanism rapidly moves proton substrate in accordance with nano-electrochemical poles on the membrane surface created by powerful proton pumps such as ATP synthase.
Collapse
Affiliation(s)
- Marcos Y Yoshinaga
- University of Bremen, MARUM - Center for Marine and Environmental Sciences, Germany.
| | - Matthias Y Kellermann
- University of California Santa Barbara - Department of Earth Science and Marine Science Institute, USA
| | - David L Valentine
- University of California Santa Barbara - Department of Earth Science and Marine Science Institute, USA
| | | |
Collapse
|
41
|
Antonenko YN, Denisov SS, Silachev DN, Khailova LS, Jankauskas SS, Rokitskaya TI, Danilina TI, Kotova EA, Korshunova GA, Plotnikov EY, Zorov DB. A long-linker conjugate of fluorescein and triphenylphosphonium as mitochondria-targeted uncoupler and fluorescent neuro- and nephroprotector. Biochim Biophys Acta Gen Subj 2016; 1860:2463-2473. [PMID: 27450891 DOI: 10.1016/j.bbagen.2016.07.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/16/2016] [Accepted: 07/16/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND Limited uncoupling of oxidative phosphorylation is known to be beneficial in various laboratory models of diseases. Linking a triphenyl-phosphonium cation to fluorescein through a decyl (C10) spacer yields a fluorescent uncoupler, coined mitoFluo, that selectively accumulates in energized mitochondria (Denisov et al., Chem.Commun. 2014). METHODS Proton-transport activity of mitoFluo was tested in liposomes reconstituted with bacteriorhodopsin. To examine the uncoupling action on mitochondria, we monitored mitochondrial membrane potential in parallel with oxygen consumption. Neuro- and nephroprotecting activity was detected by a limb-placing test and a kidney ischemia/reperfusion protocol, respectively. RESULTS We compared mitoFluo properties with those of its newly synthesized analog having a short (butyl) spacer (C4-mitoFluo). MitoFluo, but not C4-mitoFluo, caused collapse of mitochondrial membrane potential resulting in stimulation of mitochondrial respiration. The dramatic difference in the uncoupling activity of mitoFluo and C4-mitoFluo was in line with the difference in their protonophoric activity on a lipid membrane. The accumulation of mitoFluo in mitochondria was more pronounced than that of C4-mitoFluo. MitoFluo decreased the rate of ROS production in mitochondria. MitoFluo was effective in preventing consequences of brain trauma in rats: it suppressed trauma-induced brain swelling and reduced a neurological deficit. Besides, mitoFluo attenuated acute kidney injury after ischemia/reperfusion in rats. CONCLUSIONS A long alkyl linker was proved mandatory for mitoFluo to be a mitochondria- targeted uncoupler. MitoFluo showed high protective efficacy in certain models of oxidative stress-related diseases. GENERAL SIGNIFICANCE MitoFluo is a candidate for developing therapeutic and fluorescence imaging agents to treat brain and kidney pathologies.
Collapse
Affiliation(s)
- Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Stepan S Denisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia; Faculty of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Denis N Silachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ljudmila S Khailova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Stanislovas S Jankauskas
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Tatyana I Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Tatyana I Danilina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Elena A Kotova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Galina A Korshunova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Egor Y Plotnikov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Dmitry B Zorov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| |
Collapse
|
42
|
Laine RF, Kaminski Schierle GS, van de Linde S, Kaminski CF. From single-molecule spectroscopy to super-resolution imaging of the neuron: a review. Methods Appl Fluoresc 2016; 4:022004. [PMID: 28809165 PMCID: PMC5390958 DOI: 10.1088/2050-6120/4/2/022004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/09/2016] [Accepted: 05/19/2016] [Indexed: 12/03/2022]
Abstract
For more than 20 years, single-molecule spectroscopy has been providing invaluable insights into nature at the molecular level. The field has received a powerful boost with the development of the technique into super-resolution imaging methods, ca. 10 years ago, which overcome the limitations imposed by optical diffraction. Today, single molecule super-resolution imaging is routinely used in the study of macromolecular function and structure in the cell. Concomitantly, computational methods have been developed that provide information on numbers and positions of molecules at the nanometer-scale. In this overview, we outline the technical developments that have led to the emergence of localization microscopy techniques from single-molecule spectroscopy. We then provide a comprehensive review on the application of the technique in the field of neuroscience research.
Collapse
Affiliation(s)
- Romain F Laine
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, Cambridge University, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Gabriele S Kaminski Schierle
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, Cambridge University, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Sebastian van de Linde
- Department of Biotechnology and Biophysics, Julius-Maximilians-University, Am Hubland, D-97074 Würzburg, Germany
| | - Clemens F Kaminski
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, Cambridge University, Pembroke Street, Cambridge, CB2 3RA, UK
| |
Collapse
|
43
|
Agmon N, Bakker HJ, Campen RK, Henchman RH, Pohl P, Roke S, Thämer M, Hassanali A. Protons and Hydroxide Ions in Aqueous Systems. Chem Rev 2016; 116:7642-72. [PMID: 27314430 DOI: 10.1021/acs.chemrev.5b00736] [Citation(s) in RCA: 287] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the structure and dynamics of water's constituent ions, proton and hydroxide, has been a subject of numerous experimental and theoretical studies over the last century. Besides their obvious importance in acid-base chemistry, these ions play an important role in numerous applications ranging from enzyme catalysis to environmental chemistry. Despite a long history of research, many fundamental issues regarding their properties continue to be an active area of research. Here, we provide a review of the experimental and theoretical advances made in the last several decades in understanding the structure, dynamics, and transport of the proton and hydroxide ions in different aqueous environments, ranging from water clusters to the bulk liquid and its interfaces with hydrophobic surfaces. The propensity of these ions to accumulate at hydrophobic surfaces has been a subject of intense debate, and we highlight the open issues and challenges in this area. Biological applications reviewed include proton transport along the hydration layer of various membranes and through channel proteins, problems that are at the core of cellular bioenergetics.
Collapse
Affiliation(s)
- Noam Agmon
- The Fritz Haber Research Center, Institute of Chemistry, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - Huib J Bakker
- FOM Institute AMOLF , Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - R Kramer Campen
- Fritz Haber Institute of the Max Planck Society , Faradayweg 4-6, 14195 Berlin, Germany
| | - Richard H Henchman
- Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Peter Pohl
- Johannes Kepler University Linz , Institute of Biophysics, Gruberstrasse 40, 4020 Linz, Austria
| | - Sylvie Roke
- Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Material Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015, Lausanne, Switzerland
| | - Martin Thämer
- Fritz Haber Institute of the Max Planck Society , Faradayweg 4-6, 14195 Berlin, Germany.,Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | - Ali Hassanali
- CMSP Section, The Abdus Salaam International Center for Theoretical Physics , I-34151 Trieste, Italy
| |
Collapse
|
44
|
Ishigaki M, Iketani M, Sugaya M, Takahashi M, Tanaka M, Hattori S, Ohsawa I. STED super-resolution imaging of mitochondria labeled with TMRM in living cells. Mitochondrion 2016; 28:79-87. [DOI: 10.1016/j.mito.2016.03.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/26/2016] [Accepted: 03/29/2016] [Indexed: 12/31/2022]
|
45
|
An H, Brettle M, Lee T, Heng B, Lim CK, Guillemin GJ, Lord MS, Klotzsch E, Geczy CL, Bryant K, Fath T, Tedla N. Soluble LILRA3 promotes neurite outgrowth and synapses formation through high affinity interaction with Nogo 66. J Cell Sci 2016; 129:1198-209. [DOI: 10.1242/jcs.182006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/26/2016] [Indexed: 01/24/2023] Open
Abstract
Inhibitory proteins, particularly Nogo 66, a highly conserved 66 amino acid loop of Nogo A, play key roles in limiting the intrinsic capacity of the central nervous system to regenerate after injury. Ligation of surface Nogo receptors (NgRs) and/or leukocyte immunoglobulin like receptor B2 (LILRB2) and its mouse orthologue the paired-immunoglobulin-like receptor B (PIRB) by Nogo 66 transduces inhibitory signals that potently inhibit neurite outgrowth. Here we show that soluble leukocyte immunoglobulin-like receptor A3 (LILRA3) is a high affinity receptor for Nogo 66, suggesting that LILRA3 might be a competitive antagonist to these cell surface inhibitory receptors. Consistent with this, LILRA3 significantly reversed Nogo 66-mediated inhibition of neurite outgrowth and promoted synapse formation in primary cortical neurons via regulation of the MEK/ERK pathway. LILRA3 represents a new antagonist to Nogo 66-mediated inhibition of neurite outgrowth in the CNS, a function distinct from its immune-regulatory role in leukocytes. This report is also the first to demonstrate that a member of LILR family normally not expressed in rodents exerts functions on mouse neurons through the highly homologous Nogo 66 ligand.
Collapse
Affiliation(s)
- Hongyan An
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Merryn Brettle
- Neurodegeneration and Repair Unit, School of Medical Sciences, Department of Anatomy, UNSW, Sydney, Australia
| | - Terry Lee
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Benjamin Heng
- Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Macquarie University, Australia
| | - Chai K. Lim
- Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Macquarie University, Australia
| | - Gilles J. Guillemin
- Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Macquarie University, Australia
| | - Megan S. Lord
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
| | - Enrico Klotzsch
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, ARC Centre of Excellence in Advanced Molecular Imaging, The University of New South Wales, Sydney, NSW, Australia
| | - Carolyn L. Geczy
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Katherine Bryant
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| | - Thomas Fath
- Neurodegeneration and Repair Unit, School of Medical Sciences, Department of Anatomy, UNSW, Sydney, Australia
| | - Nicodemus Tedla
- Inflammation and Infection Research Centre, School of Medical Sciences, Department of Pathology, UNSW, Sydney, Australia
| |
Collapse
|
46
|
Abstract
Since the discovery of the existence of superassemblies between mitochondrial respiratory complexes, such superassemblies have been the object of a passionate debate. It is accepted that respiratory supercomplexes are structures that occur in vivo, although which superstructures are naturally occurring and what could be their functional role remain open questions. The main difficulty is to make compatible the existence of superassemblies with the corpus of data that drove the field to abandon the early understanding of the physical arrangement of the mitochondrial respiratory chain as a compact physical entity (the solid model). This review provides a nonexhaustive overview of the evolution of our understanding of the structural organization of the electron transport chain from the original idea of a compact organization to a view of freely moving complexes connected by electron carriers. Today supercomplexes are viewed not as a revival of the old solid model but rather as a refined revision of the fluid model, which incorporates a new layer of structural and functional complexity.
Collapse
Affiliation(s)
- José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain;
| |
Collapse
|
47
|
Hoang T, Kuljanin M, Smith MD, Jelokhani-Niaraki M. A biophysical study on molecular physiology of the uncoupling proteins of the central nervous system. Biosci Rep 2015; 35:e00226. [PMID: 26182433 PMCID: PMC4613710 DOI: 10.1042/bsr20150130] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 06/04/2015] [Indexed: 01/16/2023] Open
Abstract
Mitochondrial inner membrane uncoupling proteins (UCPs) facilitate transmembrane (TM) proton flux and consequently reduce the membrane potential and ATP production. It has been proposed that the three neuronal human UCPs (UCP2, UCP4 and UCP5) in the central nervous system (CNS) play significant roles in reducing cellular oxidative stress. However, the structure and ion transport mechanism of these proteins remain relatively unexplored. Recently, we reported a novel expression system for obtaining functionally folded UCP1 in bacterial membranes and applied this system to obtain highly pure neuronal UCPs in high yields. In the present study, we report on the structure and function of the three neuronal UCP homologues. Reconstituted neuronal UCPs were dominantly helical in lipid membranes and transported protons in the presence of physiologically-relevant fatty acid (FA) activators. Under similar conditions, all neuronal UCPs also exhibited chloride transport activities that were partially inhibited by FAs. CD, fluorescence and MS measurements and semi-native gel electrophoresis collectively suggest that the reconstituted proteins self-associate in the lipid membranes. Based on SDS titration experiments and other evidence, a general molecular model for the monomeric, dimeric and tetrameric functional forms of UCPs in lipid membranes is proposed. In addition to their shared structural and ion transport features, neuronal UCPs differ in their conformations and proton transport activities (and possibly mechanism) in the presence of different FA activators. The differences in FA-activated UCP-mediated proton transport could serve as an essential factor in understanding and differentiating the physiological roles of UCP homologues in the CNS.
Collapse
Affiliation(s)
- Tuan Hoang
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada, N2L 3C5 Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Miljan Kuljanin
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada, N2L 3C5
| | - Matthew D Smith
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada, N2L 3C5 Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Masoud Jelokhani-Niaraki
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada, N2L 3C5 Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| |
Collapse
|
48
|
Shibata T, Yamashita S, Hirusaki K, Katoh K, Ohta Y. Isolation of mitochondria by gentle cell membrane disruption, and their subsequent characterization. Biochem Biophys Res Commun 2015; 463:563-8. [PMID: 26036573 DOI: 10.1016/j.bbrc.2015.05.095] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 05/28/2015] [Indexed: 11/26/2022]
Abstract
Mitochondria play a key role in several physiological processes as in integrating signals in the cell. However, understanding of the mechanism by which mitochondria sense and respond to signals has been limited due to the lack of an appropriate model system. In this study, we developed a method to isolate and characterize mitochondria without cell homogenization. By gently pipetting cells treated with streptolysin-O, a pore-forming membrane protein, we disrupted the cell membrane and were able to isolate both elongated and spherical mitochondria. Fluorescence imaging combined with super resolution microscopy showed that both the outer and inner membranes of the elongated mitochondria isolated using the newly developed method were intact. In addition, a FRET-based ATP sensor expressed in the mitochondrial matrix demonstrated that ATP generation by FoF1-ATPase in the isolated elongated mitochondria was as high as that in intracellular mitochondria. On the other hand, some of the spherical mitochondria isolated with this method had the outer membrane that no longer encapsulated the inner membrane. In addition, all mitochondria isolated using conventional procedures involving homogenization were spherical, many of them had damaged membranes, and low levels of ATP generation. Our results suggest that elongated mitochondria isolated from cells through gentle cell membrane disruption using a pore-forming protein tend to be more similar to intracellular mitochondria, having an intact membrane system and higher activity than spherical mitochondria.
Collapse
Affiliation(s)
- Takahiro Shibata
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Saki Yamashita
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Kotoe Hirusaki
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Kaoru Katoh
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan
| | - Yoshihiro Ohta
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan.
| |
Collapse
|