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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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Menges G, Schacht T, Becker H, Ott S. Properties of Liquid Crystal Injection Mouldings. INT POLYM PROC 2022. [DOI: 10.1515/ipp-1987-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The suitability of liquid crystal polymers for the injection moulding process was pointed out at the time of their discovery. However, up to now, it has been assumed that the unmodified liquid crystal polymers were less suited to processing by injection moulding due to their distinct anisotropies. The direction of developments in the application of liquid crystal polymers was done mainly in another direction. We, however, have been concerned for more than four years now with this subject [3, 4, 5], even when our practical experiments could not be as comprehensive as we would wish, due to the limited availability of the raw materials. We have also been able to use this time to develop CAE programs which support the constructor in the design of injection moulds, whereby these programs enable the flow process to be simulated and therefore enabling the orientation to be seen at every point in the injection moulded part [6]. This is naturally particularly important for those materials in which the orientation of the molecules plays such a large part for the respective properties, as these are caused by the direction of the flows in the flow process. A changed runner position causes other orientations. More details should therefore be reported about our investigations to date.
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Affiliation(s)
- G. Menges
- Institut für Kunststoffverarbeitung (IKV), University of Technology , Aachen , West Germany
| | - T. Schacht
- Institut für Kunststoffverarbeitung (IKV), University of Technology , Aachen , West Germany
| | - H. Becker
- Institut für Kunststoffverarbeitung (IKV), University of Technology , Aachen , West Germany
| | - S. Ott
- Institut für Kunststoffverarbeitung (IKV), University of Technology , Aachen , West Germany
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3
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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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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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Lisak D, Schacht T, Gawlitza A, Albrecht P, Aktas O, Koop B, Gliem M, Hofstetter HH, Zanger K, Bultynck G, Parys JB, De Smedt H, Kindler T, Adams-Quack P, Hahn M, Waisman A, Reed JC, Hövelmeyer N, Methner A. BAX inhibitor-1 is a Ca(2+) channel critically important for immune cell function and survival. Cell Death Differ 2015; 23:358-68. [PMID: 26470731 DOI: 10.1038/cdd.2015.115] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 07/20/2015] [Accepted: 07/21/2015] [Indexed: 01/03/2023] Open
Abstract
The endoplasmic reticulum (ER) serves as the major intracellular Ca(2+) store and has a role in the synthesis and folding of proteins. BAX (BCL2-associated X protein) inhibitor-1 (BI-1) is a Ca(2+) leak channel also implicated in the response against protein misfolding, thereby connecting the Ca(2+) store and protein-folding functions of the ER. We found that BI-1-deficient mice suffer from leukopenia and erythrocytosis, have an increased number of splenic marginal zone B cells and higher abundance and nuclear translocation of NF-κB (nuclear factor-κ light-chain enhancer of activated B cells) proteins, correlating with increased cytosolic and ER Ca(2+) levels. When put into culture, purified knockout T cells and even more so B cells die spontaneously. This is preceded by increased activity of the mitochondrial initiator caspase-9 and correlated with a significant surge in mitochondrial Ca(2+) levels, suggesting an exhausted mitochondrial Ca(2+) buffer capacity as the underlying cause for cell death in vitro. In vivo, T-cell-dependent experimental autoimmune encephalomyelitis and B-cell-dependent antibody production are attenuated, corroborating the ex vivo results. These results suggest that BI-1 has a major role in the functioning of the adaptive immune system by regulating intracellular Ca(2+) homeostasis in lymphocytes.
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Affiliation(s)
- D Lisak
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn) and Department of Neurology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - T Schacht
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn) and Department of Neurology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - A Gawlitza
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn) and Department of Neurology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - P Albrecht
- Heinrich Heine Universität Düsseldorf, Department of Neurology, Düsseldorf, Germany
| | - O Aktas
- Heinrich Heine Universität Düsseldorf, Department of Neurology, Düsseldorf, Germany
| | - B Koop
- Heinrich Heine Universität Düsseldorf, Department of Neurology, Düsseldorf, Germany
| | - M Gliem
- Heinrich Heine Universität Düsseldorf, Department of Neurology, Düsseldorf, Germany
| | - H H Hofstetter
- Heinrich Heine Universität Düsseldorf, Department of Neurology, Düsseldorf, Germany
| | - K Zanger
- Center for Anatomy and Brain Research, Düsseldorf, Germany
| | - G Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - J B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - H De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - T Kindler
- III Medical Clinic, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - P Adams-Quack
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - M Hahn
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - A Waisman
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - J C Reed
- Sanford Burnham Institute, La Jolla, CA, USA
| | - N Hövelmeyer
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - A Methner
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn) and Department of Neurology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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6
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Lisak DA, Schacht T, Enders V, Habicht J, Kiviluoto S, Schneider J, Henke N, Bultynck G, Methner A. The transmembrane Bax inhibitor motif (TMBIM) containing protein family: Tissue expression, intracellular localization and effects on the ER CA²⁺-filling state. Biochim Biophys Acta 2015; 1853:2104-14. [PMID: 25764978 DOI: 10.1016/j.bbamcr.2015.03.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 01/19/2015] [Accepted: 03/01/2015] [Indexed: 10/23/2022]
Abstract
Bax inhibitor-1 (BI-1) is an evolutionarily conserved pH-dependent Ca²⁺ leak channel in the endoplasmic reticulum and the founding member of a family of six highly hydrophobic mammalian proteins named transmembrane BAX inhibitor motif containing (TMBIM) 1-6 with BI-1 being TMBIM6. Here we compared the structure, subcellular localization, tissue expression and the effect on the cellular Ca²⁺ homeostasis of all family members side by side. We found that all TMBIM proteins possess the di-aspartyl pH sensor responsible for pH sensing identified in TMBIM6 and its bacterial homologue BsYetJ. TMBIM1-3 and TMBIM4-6 represent two phylogenetically distinct groups that are localized in the Golgi apparatus (TMBIM1-3), endoplasmic reticulum (TMBIM4-6) or mitochondria (TMBIM5) but share a common structure of at least seven transmembrane domains with the last domain being semi-hydrophobic. TMBIM1 is mainly expressed in muscle, TMBIM2 and 3 in the nervous system, TMBIM4 and 5 are ubiquitously expressed and TMBIM6 in skeletal muscle, kidney, liver and spleen. All TMBIM proteins reduce the Ca²⁺ content of the endoplasmic reticulum, and all but TMBIM5 also reduce the cytosolic resting Ca²⁺ concentration. These results suggest that the TMBIM family has comparable functions in the maintenance of intracellular Ca²⁺ homeostasis in a wide variety of tissues. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
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Affiliation(s)
- Dmitrij A Lisak
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn(2)), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Langenbeckstr. 1, Mainz D-55131, Germany
| | - Teresa Schacht
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn(2)), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Langenbeckstr. 1, Mainz D-55131, Germany
| | - Vitalij Enders
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn(2)), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Langenbeckstr. 1, Mainz D-55131, Germany
| | - Jörn Habicht
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn(2)), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Langenbeckstr. 1, Mainz D-55131, Germany
| | - Santeri Kiviluoto
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, Leuven BE-3000, Belgium
| | - Julia Schneider
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn(2)), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Langenbeckstr. 1, Mainz D-55131, Germany
| | - Nadine Henke
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn(2)), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Langenbeckstr. 1, Mainz D-55131, Germany
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, Leuven BE-3000, Belgium
| | - Axel Methner
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn(2)), Department of Neurology, Johannes Gutenberg University Medical Center Mainz, Langenbeckstr. 1, Mainz D-55131, Germany.
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Pfeiffer A, Jaeckel M, Lewerenz J, Noack R, Pouya A, Schacht T, Hoffmann C, Winter J, Schweiger S, Schäfer MKE, Methner A. Mitochondrial function and energy metabolism in neuronal HT22 cells resistant to oxidative stress. Br J Pharmacol 2014; 171:2147-58. [PMID: 24319993 DOI: 10.1111/bph.12549] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 10/07/2013] [Accepted: 11/28/2013] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND AND PURPOSE The hippocampal cell line HT22 is an excellent model for studying the consequences of endogenous oxidative stress. Extracellular glutamate depletes cellular glutathione by blocking the glutamate/cystine antiporter system xc-. Glutathione depletion induces a well-defined programme of cell death characterized by an increase in reactive oxygen species and mitochondrial dysfunction. EXPERIMENTAL APPROACH We compared the mitochondrial shape, the abundance of mitochondrial complexes and the mitochondrial respiration of HT22 cells, selected based on their resistance to glutamate, with those of the glutamate-sensitive parental cell line. KEY RESULTS Glutamate-resistant mitochondria were less fragmented and displayed seemingly contradictory features: mitochondrial calcium and superoxide were increased while high-resolution respirometry suggested a reduction in mitochondrial respiration. This was interpreted as a reverse activity of the ATP synthase under oxidative stress, leading to hydrolysis of ATP to maintain or even elevate the mitochondrial membrane potential, suggesting these cells endure ineffective energy metabolism to protect their membrane potential. Glutamate-resistant cells were also resistant to oligomycin, an inhibitor of the ATP synthase, but sensitive to deoxyglucose, an inhibitor of hexokinases. Exchanging glucose with galactose rendered resistant cells 1000-fold more sensitive to oligomycin. These results, together with a strong increase in cytosolic hexokinase 1 and 2, a reduced lactate production and an increased activity of glucose-6-phosphate dehydrogenase, suggest that glutamate-resistant HT22 cells shuttle most available glucose towards the hexose monophosphate shunt to increase glutathione recovery. CONCLUSIONS AND IMPLICATIONS These results indicate that mitochondrial and metabolic adaptations play an important role in the resistance of cells to oxidative stress.
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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, Mainz, Germany
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Czeredys M, Gruszczynska-Biegala J, Schacht T, Methner A, Kuznicki J. Expression of genes encoding the calcium signalosome in cellular and transgenic models of Huntington's disease. Front Mol Neurosci 2013; 6:42. [PMID: 24324398 PMCID: PMC3838962 DOI: 10.3389/fnmol.2013.00042] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 11/05/2013] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disease caused by the expansion of a polyglutamine stretch in the huntingtin (HTT) protein and characterized by dysregulated calcium homeostasis. We investigated whether these disturbances are correlated with changes in the mRNA level of the genes that encode proteins involved in calcium homeostasis and signaling (i.e., the calciosome). Using custom-made TaqMan low-density arrays containing probes for 96 genes, we quantified mRNA in the striatum in YAC128 mice, a model of HD, and wildtype mice. HTT mutation caused the increased expression of some components of the calcium signalosome, including calretinin, presenilin 2, and calmyrin 1, and the increased expression of genes indirectly involved in calcium homeostasis, such as huntingtin-associated protein 1 and calcyclin-binding protein. To verify these findings in a different model, we used PC12 cells with an inducible expression of mutated full-length HTT. Using single-cell imaging with Fura-2AM, we found that store-operated Ca2+ entry but not endoplasmic reticulum (ER) store content was changed as a result of the expression of mutant HTT. Statistically significant downregulation of the Orai calcium channel subunit 2, calmodulin, and septin 4 was detected in cells that expressed mutated HTT. Our data indicate that the dysregulation of calcium homeostasis correlates with changes in the gene expression of members of the calciosome. These changes, however, differed in the two models of HD used in this study. Our results indicate that each HD model exhibits distinct features that may only partially resemble the human disease.
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Affiliation(s)
- Magdalena Czeredys
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology Warsaw, Poland
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Bein E, Anderson T, Strupp H, Henry W, Schacht T, Binder J, Butler S. The effects of training in time-limited dynamic psychotherapy: changes in therapeutic outcome. Psychother Res 2010; 10:119-32. [DOI: 10.1080/713663669] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Robbins M, Schacht T. Family Hierarchies. Am J Nurs 1982; 82:284-6. [PMID: 6915714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Winokur M, Messer SB, Schacht T. Contributions to the theory and practice of short-term dynamic psychotherapy. Bull Menninger Clin 1981; 45:125-42. [PMID: 7260454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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