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Bueno D, Narayan Dey P, Schacht T, Wolf C, Wüllner V, Morpurgo E, Rojas-Charry L, Sessinghaus L, Leukel P, Sommer C, Radyushkin K, Florin L, Baumgart J, Stamm P, Daiber A, Horta G, Nardi L, Vasic V, Schmeisser MJ, Hellwig A, Oskamp A, Bauer A, Anand R, Reichert AS, Ritz S, Nocera G, Jacob C, Peper J, Silies M, Frauenknecht KBM, Schäfer MKE, Methner A. NECAB2 is an endosomal protein important for striatal function. Free Radic Biol Med 2023; 208:643-656. [PMID: 37722569 DOI: 10.1016/j.freeradbiomed.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/29/2023] [Accepted: 09/02/2023] [Indexed: 09/20/2023]
Abstract
Synaptic signaling depends on ATP generated by mitochondria. Dysfunctional mitochondria shift the redox balance towards a more oxidative environment. Due to extensive connectivity, the striatum is especially vulnerable to mitochondrial dysfunction. We found that neuronal calcium-binding protein 2 (NECAB2) plays a role in striatal function and mitochondrial homeostasis. NECAB2 is a predominantly endosomal striatal protein which partially colocalizes with mitochondria. This colocalization is enhanced by mild oxidative stress. Global knockout of Necab2 in the mouse results in increased superoxide levels, increased DNA oxidation and reduced levels of the antioxidant glutathione which correlates with an altered mitochondrial shape and function. Striatal mitochondria from Necab2 knockout mice are more abundant and smaller and characterized by a reduced spare capacity suggestive of intrinsic uncoupling respectively mitochondrial dysfunction. In line with this, we also found an altered stress-induced interaction of endosomes with mitochondria in Necab2 knockout striatal cultures. The predominance of dysfunctional mitochondria and the pro-oxidative redox milieu correlates with a loss of striatal synapses and behavioral changes characteristic of striatal dysfunction like reduced motivation and altered sensory gating. Together this suggests an involvement of NECAB2 in an endosomal pathway of mitochondrial stress response important for striatal function.
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Affiliation(s)
- Diones Bueno
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany.
| | - Partha Narayan Dey
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany.
| | - Teresa Schacht
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany.
| | - Christina Wolf
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany.
| | - Verena Wüllner
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany.
| | - Elena Morpurgo
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany.
| | - Liliana Rojas-Charry
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany; University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Anatomy, Germany.
| | - Lena Sessinghaus
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute of Neuropathology, Germany.
| | - Petra Leukel
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute of Neuropathology, Germany.
| | - Clemens Sommer
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute of Neuropathology, Germany.
| | - Konstantin Radyushkin
- University Medical Center of the Johannes Gutenberg-University Mainz, Mouse Behavior Unit, Germany.
| | - Luise Florin
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Virology, Germany.
| | - Jan Baumgart
- University Medical Center of the Johannes Gutenberg-University Mainz, Translational Animal Research Center (TARC), Germany.
| | - Paul Stamm
- University Medical Center of the Johannes Gutenberg-University Mainz, Center for Cardiology, Germany.
| | - Andreas Daiber
- University Medical Center of the Johannes Gutenberg-University Mainz, Center for Cardiology, Germany.
| | - Guilherme Horta
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Anatomy, Germany.
| | - Leonardo Nardi
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Anatomy, Germany.
| | - Verica Vasic
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Anatomy, Germany.
| | - Michael J Schmeisser
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Anatomy, Germany.
| | - Andrea Hellwig
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, Germany.
| | - Angela Oskamp
- Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich GmbH, Germany.
| | - Andreas Bauer
- Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich GmbH, Germany.
| | - Ruchika Anand
- Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
| | - Andreas S Reichert
- Institute of Biochemistry and Molecular Biology I, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
| | - Sandra Ritz
- Institute of Molecular Biology gGmbH (IMB), Mainz, Germany.
| | - Gianluigi Nocera
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-University Mainz, Germany.
| | - Claire Jacob
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-University Mainz, Germany.
| | - Jonas Peper
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-University Mainz, Germany.
| | - Marion Silies
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg-University Mainz, Germany.
| | - Katrin B M Frauenknecht
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute of Neuropathology, Germany; Institute of Neuropathology, University and University Hospital Zurich, Switzerland.
| | - Michael K E Schäfer
- Department of Anesthesiology, University Medical Center of the Johannes Gutenberg-University Mainz, Germany.
| | - Axel Methner
- University Medical Center of the Johannes Gutenberg-University Mainz, Institute for Molecular Medicine, Germany.
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Bueno DC, Canto RFS, de Souza V, Andreguetti RR, Barbosa FAR, Naime AA, Dey PN, Wüllner V, Lopes MW, Braga AL, Methner A, Farina M. New Probucol Analogues Inhibit Ferroptosis, Improve Mitochondrial Parameters, and Induce Glutathione Peroxidase in HT22 Cells. Mol Neurobiol 2020; 57:3273-3290. [DOI: 10.1007/s12035-020-01956-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023]
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Philippaert K, Roden M, Lisak D, Bueno D, Jelenik T, Radyushkin K, Schacht T, Mesuere M, Wüllner V, Herrmann AK, Baumgart J, Vennekens R, Methner A. Bax inhibitor-1 deficiency leads to obesity by increasing Ca 2+-dependent insulin secretion. J Mol Med (Berl) 2020; 98:849-862. [PMID: 32394396 PMCID: PMC7297831 DOI: 10.1007/s00109-020-01914-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/14/2020] [Accepted: 04/21/2020] [Indexed: 12/28/2022]
Abstract
Abstract Transmembrane BAX inhibitor motif containing 6 (TMBIM6), also known as Bax inhibitor-1, is an evolutionarily conserved protein involved in endoplasmic reticulum (ER) function. TMBIM6 is an ER Ca2+ leak channel and its deficiency enhances susceptibility to ER stress due to inhibition of the ER stress sensor IRE1α. It was previously shown that TMBIM6 overexpression improves glucose metabolism and that TMBIM6 knockout mice develop obesity. We here examined the metabolic alterations underlying the obese phenotype and subjected TMBIM6 knockout mice to indirect calorimetry and euglycemic-hyperinsulinemic tests with stable isotope dilution to gauge tissue-specific insulin sensitivity. This demonstrated no changes in heat production, food intake, activity or hepatic and peripheral insulin sensitivity. TMBIM6 knockout mice, however, featured a higher glucose-stimulated insulin secretion in vivo as assessed by the hyperglycemic clamp test and hepatic steatosis. This coincided with profound changes in glucose-mediated Ca2+ regulation in isolated pancreatic β cells and increased levels of IRE1α levels but no differences in downstream effects of IRE1α like increased Xbp1 mRNA splicing or Ire1-dependent decay of insulin mRNA in the pancreas. We therefore conclude that lack of TMBIM6 does not affect insulin sensitivity but leads to hyperinsulinemia, which serves to explain the weight gain. TMBIM6-mediated metabolic alterations are mainly caused by its role as a Ca2+ release channel in the ER. Key messages TMBIM6−/− leads to obesity and hepatic steatosis. Food intake and energy expenditure are not changed in TMBIM6−/− mice. No changes in insulin resistance in TMBIM6−/− mice. Increased insulin secretion caused by altered calcium dynamics in β cells.
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Affiliation(s)
- Koenraad Philippaert
- Laboratory of Ion Channel Research, VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Michael Roden
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany. .,Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany. .,German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
| | - Dmitrij Lisak
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Diones Bueno
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Tomas Jelenik
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany.,German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | | | - Teresa Schacht
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Margot Mesuere
- Laboratory of Ion Channel Research, VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Verena Wüllner
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Ann-Kathrin Herrmann
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Jan Baumgart
- Translational Animal Research Center, The Johannes Gutenberg University, Mainz, Germany
| | - Rudi Vennekens
- Laboratory of Ion Channel Research, VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Axel Methner
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany.
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Wolf C, Zimmermann R, Thaher O, Bueno D, Wüllner V, Schäfer MKE, Albrecht P, Methner A. The Charcot-Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress. Cells 2019; 8:cells8101289. [PMID: 31640251 PMCID: PMC6830076 DOI: 10.3390/cells8101289] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 10/10/2019] [Accepted: 10/14/2019] [Indexed: 01/20/2023] Open
Abstract
Charcot–Marie tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic, and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but a similar mitochondrial oxygen consumption, membrane potential, and ATP production as wildtype cells. However, when inducing mild oxidative stress 24 h before analysis using 100 µM hydrogen peroxide, R94Q cells exhibited significantly increased respiration but decreased mitochondrial ATP production. This was accompanied by increased glucose uptake and an up-regulation of hexokinase 1 and pyruvate kinase M2, suggesting increased pyruvate shuttling into mitochondria. Interestingly, these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells. We conclude that mitochondria harboring the disease-causing R94Q mutation in MFN2 are more susceptible to oxidative stress, which causes uncoupling of respiration and ATP production possibly by a less efficient mitochondrial quality control.
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Affiliation(s)
- Christina Wolf
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Rahel Zimmermann
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Osamah Thaher
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Diones Bueno
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Verena Wüllner
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Michael K E Schäfer
- Department of Anesthesiology, Research Center for Immunotherapy (FZI), Focus Program Translational Neurosciences (FTN), University Medical Center, Johannes Gutenberg-Universität Mainz, 55116 Mainz, Germany.
| | - Philipp Albrecht
- Department of Neurology, University Hospital Düsseldorf, 40210 Düsseldorf, Germany.
| | - Axel Methner
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
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Herrmann AK, Wüllner V, Moos S, Graf J, Chen J, Kieseier B, Kurschus FC, Albrecht P, Vangheluwe P, Methner A. Dimethyl fumarate alters intracellular Ca 2+ handling in immune cells by redox-mediated pleiotropic effects. Free Radic Biol Med 2019; 141:338-347. [PMID: 31279969 DOI: 10.1016/j.freeradbiomed.2019.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 06/26/2019] [Accepted: 07/03/2019] [Indexed: 12/15/2022]
Abstract
Dimethyl fumarate (DMF) is widely used to treat the human autoimmune diseases multiple sclerosis (MS) and psoriasis. DMF causes short-term oxidative stress and activates the antioxidant response via the transcription factor Nrf2 but its immunosuppressive effect is not well understood. Immune cell activation depends on calcium signaling which itself is influenced by the cellular redox state. We therefore measured calcium, reactive oxygen species levels and glutathione content in lymphocytes from immunized mice before onset of experimental autoimmune encephalomyelitis, in peripheral blood mononuclear cells from MS patients treated with DMF, and in mouse splenocytes treated ex vivo with DMF. This demonstrated altered redox states and increased lymphocytic calcium levels in all model systems. DMF caused an immediate influx of calcium from the extracellular space, long-term increased cytosolic calcium levels and reduced calcium stored in intracellular stores. The DMF-elicited current had the electrophysiological characteristics of a transient receptor potential channel and the intracellular calcium levels were normalized by antagonists of TRPA1. Interestingly, the sarco/endoplasmic reticulum Ca2+-ATPase SERCA2b was downregulated but more active due to glutathionylation of the redox-sensitive cysteine 674. DMF therefore causes pleiotropic changes in cellular calcium homeostasis which are likely caused by redox-sensitive post-translational modifications. These changes probably contribute to its immunosuppressive effects.
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Affiliation(s)
- Ann-Kathrin Herrmann
- Institute of Molecular Medicine, University Medical Center of the Johannes Gutenberg-Universität Mainz, Mainz, Germany
| | - Verena Wüllner
- Institute of Molecular Medicine, University Medical Center of the Johannes Gutenberg-Universität Mainz, Mainz, Germany
| | - Sonja Moos
- Institute of Molecular Medicine, University Medical Center of the Johannes Gutenberg-Universität Mainz, Mainz, Germany
| | - Jonas Graf
- Dept. of Neurology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Jialin Chen
- Dept. of Cellular and Molecular Medicine, KU Leuven, Leudven, Belgium
| | - Bernd Kieseier
- Dept. of Neurology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Florian C Kurschus
- Institute of Molecular Medicine, University Medical Center of the Johannes Gutenberg-Universität Mainz, Mainz, Germany
| | - Philipp Albrecht
- Dept. of Neurology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Peter Vangheluwe
- Dept. of Cellular and Molecular Medicine, KU Leuven, Leudven, Belgium
| | - Axel Methner
- Institute of Molecular Medicine, University Medical Center of the Johannes Gutenberg-Universität Mainz, Mainz, Germany.
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Pfeiffer A, Schneider J, Bueno D, Dolga A, Voss TD, Lewerenz J, Wüllner V, Methner A. Bcl-x L knockout attenuates mitochondrial respiration and causes oxidative stress that is compensated by pentose phosphate pathway activity. Free Radic Biol Med 2017; 112:350-359. [PMID: 28807815 DOI: 10.1016/j.freeradbiomed.2017.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 08/01/2017] [Accepted: 08/08/2017] [Indexed: 12/12/2022]
Abstract
Bcl-xL is an anti-apoptotic protein that localizes to the outer mitochondrial membrane and influences mitochondrial bioenergetics by controlling Ca2+ influx into mitochondria. Here, we analyzed the effect of mitochondrial Bcl-xL on mitochondrial shape and function in knockout (KO), wild type and rescued mouse embryonic fibroblast cell lines. Mitochondria of KO cells were more fragmented, exhibited a reduced ATP concentration, and reduced oxidative phosphorylation (OXPHOS) suggesting an increased importance of ATP generation by other means. Under steady-state conditions, acidification of the growth medium as a readout for glycolysis was similar, but upon inhibition of ATP synthase with oligomycin, KO cells displayed an instant increase in glycolysis. In addition, forced energy production through OXPHOS by replacing glucose with galactose in the growth medium rendered KO cells more susceptible to mitochondrial toxins. KO cells had increased cellular reactive oxygen species and were more susceptible to oxidative stress, but had higher glutathione levels, which were however more rapidly consumed under conditions of oxidative stress. This coincided with an increased activity and protein abundance of the pentose phosphate pathway protein glucose-6-phosphate dehydrogenase, which generates NADPH necessary to regenerate reduced glutathione. KO cells were also less susceptible to pharmacological inhibition of the pentose phosphate pathway. We conclude that mitochondrial Bcl-xL is involved in maintaining mitochondrial respiratory capacity. Its deficiency causes oxidative stress, which is associated with an increased glycolytic capacity and balanced by an increased activity of the pentose phosphate pathway.
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Affiliation(s)
- Annika Pfeiffer
- Department of Neurology, University Medical Center and Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Julia Schneider
- Department of Neurology, University Medical Center and Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Diones Bueno
- Department of Neurology, University Medical Center and Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Amalia Dolga
- Department of Molecular Pharmacology, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Timo-Daniel Voss
- Universitäts, und Rehabilitationskliniken Ulm, Oberer Eselsberg 45, 89081 Ulm, Germany
| | - Jan Lewerenz
- Universitäts, und Rehabilitationskliniken Ulm, Oberer Eselsberg 45, 89081 Ulm, Germany
| | - Verena Wüllner
- Department of Neurology, University Medical Center and Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Axel Methner
- Department of Neurology, University Medical Center and Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany.
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Thaher O, Wolf C, Dey PN, Pouya A, Wüllner V, Tenzer S, Methner A. The thiol switch C684 in Mitofusin-2 mediates redox-induced alterations of mitochondrial shape and respiration. Neurochem Int 2017; 117:167-173. [PMID: 28527631 DOI: 10.1016/j.neuint.2017.05.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/08/2017] [Accepted: 05/14/2017] [Indexed: 12/15/2022]
Abstract
Mitofusin-2 (MFN2) is a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. MFN2 also plays a role in mitochondrial fusion induced by changes in the intracellular redox state. Adding oxidized glutathione (GSSG), the core cellular stress indicator, to mitochondrial preparations stimulates mitochondrial fusion by inducing disulphide bond-mediated oligomer formation of MFN2 and its homolog MFN1 which involve cysteine 684 (C684) of MFN2. Mitochondrial hyperfusion represents an adaptive stress response that confers transient protection by increasing mitochondrial ATP production but how this depends on the thiol switch C684 in MFN2 has not been investigated. We now studied mitochondrial function using high-resolution respirometry in cells stably expressing wildtype or C684A MFN2 in MFN2-deficient fibroblasts in response to alterations of the redox state. Empty vector and untransfected cells served as controls. A single treatment of cells with 100 μM hydrogen peroxide 24 h before analysis had no effect on wildtype cells, but normalized the otherwise increased respiration of knockout cells and significantly increased respiration in C684A cells. In line with this, treating permeabilized cells for 10 min with 1 mM GSH greatly reduced respiration only in C684A cells. Our data indicate that mutation of this cysteine which forms disulphide bridges in an oxidative state, apparently renders MFN2 more susceptible to alterations of the redox environment. It remains to be investigated whether other posttranslational modifications like glutathionylation might play an additional role.
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Affiliation(s)
- Osamah Thaher
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Christina Wolf
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Partha Narayan Dey
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Alireza Pouya
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Verena Wüllner
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Stefan Tenzer
- Institute for Immunology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Axel Methner
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
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Sahu SK, Fritz A, Tiwari N, Kovacs Z, Pouya A, Wüllner V, Bora P, Schacht T, Baumgart J, Peron S, Berninger B, Tiwari VK, Methner A. TOX3 regulates neural progenitor identity. Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms 2016; 1859:833-40. [DOI: 10.1016/j.bbagrm.2016.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/11/2016] [Accepted: 04/07/2016] [Indexed: 01/19/2023]
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