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Bredehöft J, Dolga AM, Honrath B, Wache S, Mazurek S, Culmsee C, Schoemaker RG, Gerstberger R, Roth J, Rummel C. SK-Channel Activation Alters Peripheral Metabolic Pathways in Mice, but Not Lipopolysaccharide-Induced Fever or Inflammation. J Inflamm Res 2022; 15:509-531. [PMID: 35115803 PMCID: PMC8800008 DOI: 10.2147/jir.s338812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/25/2021] [Indexed: 12/19/2022] Open
Abstract
Purpose Previously, we have shown that CyPPA (cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine), a pharmacological small-conductance calcium-activated potassium (SK)–channel positive modulator, antagonizes lipopolysaccharide (LPS)-induced cytokine expression in microglial cells. Here, we aimed to test its therapeutic potential for brain-controlled sickness symptoms, brain inflammatory response during LPS-induced systemic inflammation, and peripheral metabolic pathways in mice. Methods Mice were pretreated with CyPPA (15 mg/kg IP) 24 hours before and simultaneously with LPS stimulation (2.5 mg/kg IP), and the sickness response was recorded by a telemetric system for 24 hours. A second cohort of mice were euthanized 2 hours after CyPPA or solvent treatment to assess underlying CyPPA-induced mechanisms. Brain, blood, and liver samples were analyzed for inflammatory mediators or nucleotide concentrations using immunohistochemistry, real-time PCR and Western blot, or HPLC. Moreover, we investigated CyPPA-induced changes of UCP1 expression in brown adipose tissue (BAT)–explant cultures. Results CyPPA treatment did not affect LPS-induced fever, anorexia, adipsia, or expression profiles of inflammatory mediators in the hypothalamus or plasma or microglial reactivity to LPS (CD11b staining and CD68 mRNA expression). However, CyPPA alone induced a rise in core body temperature linked to heat production via altered metabolic pathways like reduced levels of adenosine, increased protein content, and increased UCP1 expression in BAT-explant cultures, but no alteration in ATP/ADP concentrations in the liver. CyPPA treatment was accompanied by altered pathways, including NFκB signaling, in the hypothalamus and cortex, while circulating cytokines remained unaltered. Conclusion Overall, while CyPPA has promise as a treatment strategy, in particular according to results from in vitro experiments, we did not reveal anti-inflammatory effects during severe LPS-induced systemic inflammation. Interestingly, we found that CyPPA alters metabolic pathways inducing short hyperthermia, most likely due to increased energy turnover in the liver and heat production in BAT.
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Affiliation(s)
- Janne Bredehöft
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Amalia M Dolga
- Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, Netherlands
| | - Birgit Honrath
- Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, Netherlands
- Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
| | - Sybille Wache
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Sybille Mazurek
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior-CMBB, Giessen and Marburg, Germany
| | - Regien G Schoemaker
- Department of Neurobiology, GELIFES, University of Groningen, Groningen, Netherlands
| | - Rüdiger Gerstberger
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Joachim Roth
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
- Center for Mind, Brain and Behavior-CMBB, Giessen and Marburg, Germany
| | - Christoph Rummel
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
- Center for Mind, Brain and Behavior-CMBB, Giessen and Marburg, Germany
- Correspondence: Christoph Rummel Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Frankfurter Strasse 100, GiessenD-35392, GermanyTel +49 641 99 38155Fax +49 641 99 38159 Email
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Krabbendam IE, Honrath B, Dilberger B, Iannetti EF, Branicky RS, Meyer T, Evers B, Dekker FJ, Koopman WJH, Beyrath J, Bano D, Schmidt M, Bakker BM, Hekimi S, Culmsee C, Eckert GP, Dolga AM. SK channel-mediated metabolic escape to glycolysis inhibits ferroptosis and supports stress resistance in C. elegans. Cell Death Dis 2020; 11:263. [PMID: 32327637 PMCID: PMC7181639 DOI: 10.1038/s41419-020-2458-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 04/01/2020] [Accepted: 04/01/2020] [Indexed: 12/25/2022]
Abstract
Metabolic flexibility is an essential characteristic of eukaryotic cells in order to adapt to physiological and environmental changes. Especially in mammalian cells, the metabolic switch from mitochondrial respiration to aerobic glycolysis provides flexibility to sustain cellular energy in pathophysiological conditions. For example, attenuation of mitochondrial respiration and/or metabolic shifts to glycolysis result in a metabolic rewiring that provide beneficial effects in neurodegenerative processes. Ferroptosis, a non-apoptotic form of cell death triggered by an impaired redox balance is gaining attention in the field of neurodegeneration. We showed recently that activation of small-conductance calcium-activated K+ (SK) channels modulated mitochondrial respiration and protected neuronal cells from oxidative death. Here, we investigated whether SK channel activation with CyPPA induces a glycolytic shift thereby increasing resilience of neuronal cells against ferroptosis, induced by erastin in vitro and in the nematode C. elegans exposed to mitochondrial poisons in vivo. High-resolution respirometry and extracellular flux analysis revealed that CyPPA, a positive modulator of SK channels, slightly reduced mitochondrial complex I activity, while increasing glycolysis and lactate production. Concomitantly, CyPPA rescued the neuronal cells from ferroptosis, while scavenging mitochondrial ROS and inhibiting glycolysis reduced its protection. Furthermore, SK channel activation increased survival of C. elegans challenged with mitochondrial toxins. Our findings shed light on metabolic mechanisms promoted through SK channel activation through mitohormesis, which enhances neuronal resilience against ferroptosis in vitro and promotes longevity in vivo.
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Affiliation(s)
- Inge E Krabbendam
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Birgit Honrath
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
- German Center for Neurodegenerative Diseases (DZNE) e.V., Sigmund-Freud-Straße 27, 53127, Bonn, Germany
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Philipps-Universität Marburg, Karl-von-Frisch-Straße 2, Marburg, 35032, Germany
| | - Benjamin Dilberger
- Faculty of Agricultural Sciences, Nutritional Sciences, and Environmental Management, Institute of Nutritional Sciences, Justus-Liebig-University of Giessen, 35392, Giessen, Germany
| | - Eligio F Iannetti
- Khondrion, Philips van Leydenlaan 15, 6525EX, Nijmegen, The Netherlands
| | - Robyn S Branicky
- Department of Biology, McGill University, 1205 Ave Docteur Penfield, Montreal, QC, H3A 1B1, Canada
| | - Tammo Meyer
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Bernard Evers
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Frank J Dekker
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, Groningen, The Netherlands
| | - Werner J H Koopman
- Radboud University Medical Center, Department of Biochemistry (286), Nijmegen, The Netherlands
| | - Julien Beyrath
- Khondrion, Philips van Leydenlaan 15, 6525EX, Nijmegen, The Netherlands
| | - Daniele Bano
- German Center for Neurodegenerative Diseases (DZNE) e.V., Sigmund-Freud-Straße 27, 53127, Bonn, Germany
| | - Martina Schmidt
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Barbara M Bakker
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Siegfried Hekimi
- Department of Biology, McGill University, 1205 Ave Docteur Penfield, Montreal, QC, H3A 1B1, Canada
| | - Carsten Culmsee
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Philipps-Universität Marburg, Karl-von-Frisch-Straße 2, Marburg, 35032, Germany
- Center for Mind Brain and Behavior-CMBB, University of Marburg, Hans-Meerwein-Straße 6, 35032, Marburg, Germany
| | - Gunter P Eckert
- Faculty of Agricultural Sciences, Nutritional Sciences, and Environmental Management, Institute of Nutritional Sciences, Justus-Liebig-University of Giessen, 35392, Giessen, Germany
| | - Amalia M Dolga
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands.
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Deville S, Honrath B, Tran QTD, Fejer G, Lambrichts I, Nelissen I, Dolga AM, Salvati A. Time-resolved characterization of the mechanisms of toxicity induced by silica and amino-modified polystyrene on alveolar-like macrophages. Arch Toxicol 2019; 94:173-186. [PMID: 31677074 DOI: 10.1007/s00204-019-02604-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/23/2019] [Indexed: 12/21/2022]
Abstract
Macrophages play a major role in the removal of foreign materials, including nano-sized materials, such as nanomedicines and other nanoparticles, which they accumulate very efficiently. Because of this, it is recognized that for a safe development of nanotechnologies and nanomedicine, it is essential to investigate potential effects induced by nano-sized materials on macrophages. To this aim, in this work, a recently established model of primary murine alveolar-like macrophages was used to investigate macrophage responses to two well-known nanoparticle models: 50 nm amino-modified polystyrene, known to induce cell death via lysosomal damage and apoptosis in different cell types, and 50 nm silica nanoparticles, which are generally considered non-toxic. Then, a time-resolved study was performed to characterize in detail the response of the macrophages following exposure to the two nanoparticles. As expected, exposure to the amino-modified polystyrene led to cell death, but surprisingly no lysosomal swelling or apoptosis were detected. On the contrary, a peculiar mitochondrial membrane hyperpolarization was observed, accompanied by endoplasmic reticulum stress (ER stress), increased cellular reactive oxygen species (ROS) and changes of metabolic activity, ultimately leading to cell death. Strong toxic responses were observed also after exposure to silica, which included mitochondrial ROS production, mitochondrial depolarization and cell death by apoptosis. Overall, these results showed that exposure to the two nanoparticles led to a very different series of intracellular events, suggesting that the macrophages responded differently to the two nanoparticle models. Similar time-resolved studies are required to characterize the response of macrophages to nanoparticles, as a key parameter in nanosafety assessment.
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Affiliation(s)
- Sarah Deville
- Department Pharmacokinetics, Toxicology and Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Health Department, Flemish Institute for Technological Research, Mol, Belgium
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Birgit Honrath
- Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, The Netherlands
| | - Quynh T D Tran
- Department Pharmacokinetics, Toxicology and Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Gyorgy Fejer
- School of Biomedical Sciences, Faculty of Medicine and Dentistry, Plymouth University, Derriford Research Facility, Plymouth, UK
| | - Ivo Lambrichts
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Inge Nelissen
- Health Department, Flemish Institute for Technological Research, Mol, Belgium
| | - Amalia M Dolga
- Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, The Netherlands
| | - Anna Salvati
- Department Pharmacokinetics, Toxicology and Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
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Dolga A, Krabbendam I, Honrath B, Dilberger B, Schmidt M, Eckert G, Culmsee C. Metabolic escape to glycolysis through SK channel activation inhibits ferroptosis and increases the life span of C. elegans in conditions of heat stress. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.665.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Amalia Dolga
- Molecular PharmacologyGroningen Research Institute of Pharmacy, University of GroningenGroningenNetherlands
| | - Inge Krabbendam
- Molecular PharmacologyGroningen Research Institute of Pharmacy, University of GroningenGroningenNetherlands
| | - Birgit Honrath
- Molecular PharmacologyGroningen Research Institute of Pharmacy, University of GroningenGroningenNetherlands
| | - Benjamin Dilberger
- Institut für ErnährungswissenschaftJustus‐Liebig‐Universität GieβenGiessenGermany
| | - Martina Schmidt
- Molecular PharmacologyGroningen Research Institute of Pharmacy, University of GroningenGroningenNetherlands
| | - Gunter Eckert
- Institut für ErnährungswissenschaftJustus‐Liebig‐Universität GieβenGiessenGermany
| | - Carsten Culmsee
- Institut für Pharmakologie und Klinische PharmaziePhilipps Universitaet MarburgMarburgGermany
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Honrath B, Krabbendam IE, IJsebaart C, Pegoretti V, Bendridi N, Rieusset J, Schmidt M, Culmsee C, Dolga AM. SK channel activation is neuroprotective in conditions of enhanced ER-mitochondrial coupling. Cell Death Dis 2018; 9:593. [PMID: 29789578 PMCID: PMC5964177 DOI: 10.1038/s41419-018-0590-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 04/08/2018] [Accepted: 04/12/2018] [Indexed: 12/26/2022]
Abstract
Alterations in the strength and interface area of contact sites between the endoplasmic reticulum (ER) and mitochondria contribute to calcium (Ca2+) dysregulation and neuronal cell death, and have been implicated in the pathology of several neurodegenerative diseases. Weakening this physical linkage may reduce Ca2+ uptake into mitochondria, while fortifying these organelle contact sites may promote mitochondrial Ca2+ overload and cell death. Small conductance Ca2+-activated K+ (SK) channels regulate mitochondrial respiration, and their activation attenuates mitochondrial damage in paradigms of oxidative stress. In the present study, we enhanced ER–mitochondrial coupling and investigated the impact of SK channels on survival of neuronal HT22 cells in conditions of oxidative stress. Using genetically encoded linkers, we show that mitochondrial respiration and the vulnerability of neuronal cells to oxidative stress was inversely linked to the strength of ER–mitochondrial contact points and the increase in mitochondrial Ca2+ uptake. Pharmacological activation of SK channels provided protection against glutamate-induced cell death and also in conditions of increased ER–mitochondrial coupling. Together, this study revealed that SK channel activation provided persistent neuroprotection in the paradigm of glutamate-induced oxytosis even in conditions where an increase in ER–mitochondrial coupling potentiated mitochondrial Ca2+ influx and impaired mitochondrial bioenergetics.
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Affiliation(s)
- Birgit Honrath
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043, Marburg, Germany. .,Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Research School of Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, 9713 AV, Groningen, The Netherlands.
| | - Inge E Krabbendam
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Research School of Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Carmen IJsebaart
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Research School of Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Valentina Pegoretti
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Research School of Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Nadia Bendridi
- INSERM U1060, INRA U1235, Laboratoire CarMeN, Lyon University, Université Claude Bernard Lyon1, INSA-Lyon, F-69921, Oullins, France
| | - Jennifer Rieusset
- INSERM U1060, INRA U1235, Laboratoire CarMeN, Lyon University, Université Claude Bernard Lyon1, INSA-Lyon, F-69921, Oullins, France
| | - Martina Schmidt
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Research School of Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043, Marburg, Germany
| | - Amalia M Dolga
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043, Marburg, Germany. .,Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Research School of Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, 9713 AV, Groningen, The Netherlands.
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Honrath B, Culmsee C, Dolga AM. One protein, different cell fate: the differential outcome of depleting GRP75 during oxidative stress in neurons. Cell Death Dis 2018; 9:32. [PMID: 29348426 PMCID: PMC5833832 DOI: 10.1038/s41419-017-0148-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Birgit Honrath
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043, Marburg, Germany.
- Department of Molecular Pharmacology, Faculty of Science and Engineering, University of Groningen, 9713 AV, Groningen, The Netherlands.
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043, Marburg, Germany
| | - Amalia M Dolga
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043, Marburg, Germany.
- Department of Molecular Pharmacology, Faculty of Science and Engineering, University of Groningen, 9713 AV, Groningen, The Netherlands.
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7
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Honrath B, Metz I, Bendridi N, Rieusset J, Culmsee C, Dolga AM. Glucose-regulated protein 75 determines ER-mitochondrial coupling and sensitivity to oxidative stress in neuronal cells. Cell Death Discov 2017; 3:17076. [PMID: 29367884 PMCID: PMC5672593 DOI: 10.1038/cddiscovery.2017.76] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 01/20/2023] Open
Abstract
The crosstalk between different organelles allows for the exchange of proteins, lipids and ions. Endoplasmic reticulum (ER) and mitochondria are physically linked and signal through the mitochondria-associated membrane (MAM) to regulate the transfer of Ca2+ from ER stores into the mitochondrial matrix, thereby affecting mitochondrial function and intracellular Ca2+ homeostasis. The chaperone glucose-regulated protein 75 (GRP75) is a key protein expressed at the MAM interface which regulates ER–mitochondrial Ca2+ transfer. Previous studies revealed that modulation of GRP75 expression largely affected mitochondrial integrity and vulnerability to cell death. In the present study, we show that genetic ablation of GRP75, by weakening ER–mitochondrial junctions, provided protection against mitochondrial dysfunction and cell death in a model of glutamate-induced oxidative stress. Interestingly, GRP75 silencing attenuated both cytosolic and mitochondrial Ca2+ overload in conditions of oxidative stress, blocked the formation of reactive oxygen species and preserved mitochondrial respiration. These data revealed a major role for GRP75 in regulating mitochondrial function, Ca2+ and redox homeostasis. In line, GRP75 overexpression enhanced oxidative cell death induced by glutamate. Overall, our findings suggest weakening ER–mitochondrial connectivity by GRP75 inhibition as a novel protective approach in paradigms of oxidative stress in neuronal cells.
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Affiliation(s)
- Birgit Honrath
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany.,Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
| | - Isabell Metz
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany
| | - Nadia Bendridi
- Laboratoire CarMeN, INSERM U1060, INRA U1235, Lyon University, Université Claude Bernard Lyon1, INSA-Lyon, Oullins, France
| | - Jennifer Rieusset
- Laboratoire CarMeN, INSERM U1060, INRA U1235, Lyon University, Université Claude Bernard Lyon1, INSA-Lyon, Oullins, France
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany
| | - Amalia M Dolga
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany.,Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
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Krabbendam IE, Honrath B, Culmsee C, Dolga AM. Mitochondrial Ca 2+-activated K + channels and their role in cell life and death pathways. Cell Calcium 2017; 69:101-111. [PMID: 28818302 DOI: 10.1016/j.ceca.2017.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [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: 04/08/2017] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 12/18/2022]
Abstract
Ca2+-activated K+ channels (KCa) are expressed at the plasma membrane and in cellular organelles. Expression of all KCa channel subtypes (BK, IK and SK) has been detected at the inner mitochondrial membrane of several cell types. Primary functions of these mitochondrial KCa channels include the regulation of mitochondrial ROS production, maintenance of the mitochondrial membrane potential and preservation of mitochondrial calcium homeostasis. These channels are therefore thought to contribute to cellular protection against oxidative stress through mitochondrial mechanisms of preconditioning. In this review, we summarize the current knowledge on mitochondrial KCa channels, and their role in mitochondrial function in relation to cell death and survival pathways. More specifically, we systematically discuss studies on the role of these mitochondrial KCa channels in pharmacological preconditioning, and according protective effects on ischemic insults to the brain and the heart.
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Affiliation(s)
- Inge E Krabbendam
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands.
| | - Birgit Honrath
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands; Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany.
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany.
| | - Amalia M Dolga
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands.
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Honrath B, Krabbendam IE, Culmsee C, Dolga AM. Small conductance Ca 2+-activated K + channels in the plasma membrane, mitochondria and the ER: Pharmacology and implications in neuronal diseases. Neurochem Int 2017; 109:13-23. [PMID: 28511953 DOI: 10.1016/j.neuint.2017.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [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: 02/17/2017] [Revised: 04/24/2017] [Accepted: 05/08/2017] [Indexed: 12/14/2022]
Abstract
Ca2+-activated K+ (KCa) channels regulate after-hyperpolarization in many types of neurons in the central and peripheral nervous system. Small conductance Ca2+-activated K+ (KCa2/SK) channels, a subfamily of KCa channels, are widely expressed in the nervous system, and in the cardiovascular system. Voltage-independent SK channels are activated by alterations in intracellular Ca2+ ([Ca2+]i) which facilitates the opening of these channels through binding of Ca2+ to calmodulin that is constitutively bound to the SK2 C-terminus. In neurons, SK channels regulate synaptic plasticity and [Ca2+]i homeostasis, and a number of recent studies elaborated on the emerging neuroprotective potential of SK channel activation in conditions of excitotoxicity and cerebral ischemia, as well as endoplasmic reticulum (ER) stress and oxidative cell death. Recently, SK channels were discovered in the inner mitochondrial membrane and in the membrane of the endoplasmic reticulum which sheds new light on the underlying molecular mechanisms and pathways involved in SK channel-mediated protective effects. In this review, we will discuss the protective properties of pharmacological SK channel modulation with particular emphasis on intracellularly located SK channels as potential therapeutic targets in paradigms of neuronal dysfunction.
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Affiliation(s)
- Birgit Honrath
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany; Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands
| | - Inge E Krabbendam
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany
| | - Amalia M Dolga
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany; Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands.
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Maher P, van Leyen K, Dey PN, Honrath B, Dolga A, Methner A. The role of Ca 2+ in cell death caused by oxidative glutamate toxicity and ferroptosis. Cell Calcium 2017; 70:47-55. [PMID: 28545724 DOI: 10.1016/j.ceca.2017.05.007] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 05/11/2017] [Accepted: 05/11/2017] [Indexed: 12/21/2022]
Abstract
Ca2+ ions play a fundamental role in cell death mediated by oxidative glutamate toxicity or oxytosis, a form of programmed cell death similar and possibly identical to other forms of cell death like ferroptosis. Ca2+ influx from the extracellular space occurs late in a cascade characterized by depletion of the intracellular antioxidant glutathione, increases in cytosolic reactive oxygen species and mitochondrial dysfunction. Here, we aim to compare oxidative glutamate toxicity with ferroptosis, address the signaling pathways that culminate in Ca2+ influx and cell death and discuss the proteins that mediate this. Recent evidence hints toward a role of the machinery responsible for store-operated Ca2+ entry (SOCE), which refills the endoplasmic reticulum (ER) after receptor-mediated ER Ca2+ release or other forms of store depletion. Pharmacological inhibition of SOCE or transcriptional downregulation of proteins involved in SOCE like the ER Ca2+ sensor STIM1, the plasma membrane Ca2+ channels Orai1 and TRPC1 and the linking protein Homer protects against oxidative glutamate toxicity and direct oxidative stress caused by hydrogen peroxide or 1-methyl-4-phenylpyridinium (MPP+) injury, a cellular model of Parkinson's disease. This suggests that SOCE inhibition might have some potential therapeutic effects in human disease associated with oxidative stress like neurodegenerative disorders.
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Affiliation(s)
- Pamela Maher
- Cellular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | - Partha Narayan Dey
- University Medical Center and Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg University Mainz, Department of Neurology, Mainz, Germany
| | - Birgit Honrath
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
| | - Amalia Dolga
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
| | - Axel Methner
- University Medical Center and Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg University Mainz, Department of Neurology, Mainz, Germany.
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11
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Honrath B, Matschke L, Meyer T, Magerhans L, Perocchi F, Ganjam GK, Zischka H, Krasel C, Gerding A, Bakker BM, Bünemann M, Strack S, Decher N, Culmsee C, Dolga AM. SK2 channels regulate mitochondrial respiration and mitochondrial Ca 2+ uptake. Cell Death Differ 2017; 24:761-773. [PMID: 28282037 DOI: 10.1038/cdd.2017.2] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 11/29/2016] [Accepted: 12/14/2016] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial calcium ([Ca2+]m) overload and changes in mitochondrial metabolism are key players in neuronal death. Small conductance calcium-activated potassium (SK) channels provide protection in different paradigms of neuronal cell death. Recently, SK channels were identified at the inner mitochondrial membrane, however, their particular role in the observed neuroprotection remains unclear. Here, we show a potential neuroprotective mechanism that involves attenuation of [Ca2+]m uptake upon SK channel activation as detected by time lapse mitochondrial Ca2+ measurements with the Ca2+-binding mitochondria-targeted aequorin and FRET-based [Ca2+]m probes. High-resolution respirometry revealed a reduction in mitochondrial respiration and complex I activity upon pharmacological activation and overexpression of mitochondrial SK2 channels resulting in reduced mitochondrial ROS formation. Overexpression of mitochondria-targeted SK2 channels enhanced mitochondrial resilience against neuronal death, and this effect was inhibited by overexpression of a mitochondria-targeted dominant-negative SK2 channel. These findings suggest that SK channels provide neuroprotection by reducing [Ca2+]m uptake and mitochondrial respiration in conditions, where sustained mitochondrial damage determines progressive neuronal death.
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Affiliation(s)
- Birgit Honrath
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany.,Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
| | - Lina Matschke
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Tammo Meyer
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
| | - Lena Magerhans
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany
| | - Fabiana Perocchi
- Gene Center/Department of Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany.,Institute for Obesity and Diabetes, Helmholtz Zentrum München, Neuherberg, Germany
| | - Goutham K Ganjam
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany
| | - Hans Zischka
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Neuherberg, Germany
| | - Cornelius Krasel
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany
| | - Albert Gerding
- Center for Liver, Digestive and Metabolic Diseases, Department of Pediatrics & Systems Biology Center for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Barbara M Bakker
- Center for Liver, Digestive and Metabolic Diseases, Department of Pediatrics & Systems Biology Center for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Moritz Bünemann
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany
| | - Stefan Strack
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany
| | - Amalia M Dolga
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany.,Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Behavioural and Cognitive Neurosciences (BCN), Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands
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12
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Eleftheriadis N, Poelman H, Leus NGJ, Honrath B, Neochoritis CG, Dolga A, Dömling A, Dekker FJ. Design of a novel thiophene inhibitor of 15-lipoxygenase-1 with both anti-inflammatory and neuroprotective properties. Eur J Med Chem 2016; 122:786-801. [PMID: 27477687 DOI: 10.1016/j.ejmech.2016.07.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 01/18/2023]
Abstract
The enzyme 15-lipoxygenase-1 (15-LOX-1) plays a dual role in diseases with an inflammatory component. On one hand 15-LOX-1 plays a role in pro-inflammatory gene expression and on the other hand it has been shown to be involved in central nervous system (CNS) disorders by its ability to mediate oxidative stress and damage of mitochondrial membranes under hypoxic conditions. In order to further explore applications in the CNS, novel 15-LOX-1 inhibitors with favorable physicochemical properties need to be developed. Here, we present Substitution Oriented Screening (SOS) in combination with Multi Component Chemistry (MCR) as an effective strategy to identify a diversely substituted small heterocyclic inhibitors for 15-LOX-1, denoted ThioLox, with physicochemical properties superior to previously identified inhibitors. Ex vivo biological evaluation in precision-cut lung slices (PCLS) showed inhibition of pro-inflammatory gene expression and in vitro studies on neuronal HT-22 cells showed a strong protection against glutamate toxicity for this 15-LOX-1 inhibitor. This provides a novel approach to identify novel small with favorable physicochemical properties for exploring 15-LOX-1 as a drug target in inflammatory diseases and neurodegeneration.
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Affiliation(s)
- Nikolaos Eleftheriadis
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, 9713 AV, The Netherlands
| | - Hessel Poelman
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, 9713 AV, The Netherlands
| | - Niek G J Leus
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, 9713 AV, The Netherlands
| | - Birgit Honrath
- Institute of Pharmacology and Clinical Pharmacy, Philipps-University Marburg, Marburg, Germany
| | - Constantinos G Neochoritis
- Department of Drug Design, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, 9713 AV, The Netherlands
| | - Amalia Dolga
- Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, 9713 AV, The Netherlands
| | - Alexander Dömling
- Department of Drug Design, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, 9713 AV, The Netherlands
| | - Frank J Dekker
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, 9713 AV, The Netherlands
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13
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Neitemeier S, Dolga AM, Honrath B, Karuppagounder SS, Alim I, Ratan RR, Culmsee C. Inhibition of HIF-prolyl-4-hydroxylases prevents mitochondrial impairment and cell death in a model of neuronal oxytosis. Cell Death Dis 2016; 7:e2214. [PMID: 27148687 PMCID: PMC4917646 DOI: 10.1038/cddis.2016.107] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 02/23/2016] [Accepted: 03/22/2016] [Indexed: 12/24/2022]
Abstract
Mitochondrial impairment induced by oxidative stress is a main characteristic of intrinsic cell death pathways in neurons underlying the pathology of neurodegenerative diseases. Therefore, protection of mitochondrial integrity and function is emerging as a promising strategy to prevent neuronal damage. Here, we show that pharmacological inhibition of hypoxia-inducible factor prolyl-4-hydroxylases (HIF-PHDs) by adaptaquin inhibits lipid peroxidation and fully maintains mitochondrial function as indicated by restored mitochondrial membrane potential and ATP production, reduced formation of mitochondrial reactive oxygen species (ROS) and preserved mitochondrial respiration, thereby protecting neuronal HT-22 cells in a model of glutamate-induced oxytosis. Selective reduction of PHD1 protein using CRISPR/Cas9 technology also reduced both lipid peroxidation and mitochondrial impairment, and attenuated glutamate toxicity in the HT-22 cells. Regulation of activating transcription factor 4 (ATF4) expression levels and related target genes may mediate these beneficial effects. Overall, these results expose HIF-PHDs as promising targets to protect mitochondria and, thereby, neurons from oxidative cell death.
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Affiliation(s)
- S Neitemeier
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Fachbereich Pharmazie, Philipps-Universität Marburg, Karl-von-Frisch-Straße 1, Marburg 35032, Germany
| | - A M Dolga
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Fachbereich Pharmazie, Philipps-Universität Marburg, Karl-von-Frisch-Straße 1, Marburg 35032, Germany
| | - B Honrath
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Fachbereich Pharmazie, Philipps-Universität Marburg, Karl-von-Frisch-Straße 1, Marburg 35032, Germany
| | - S S Karuppagounder
- Burke-Cornell Medical Research Institute, White Plains, NY, USA.,Feil Family Brain and Mind Research Institute, Department of Neurology and Neuroscience, Weill Medical College, Cornell University, New York, NY, USA
| | - I Alim
- Burke-Cornell Medical Research Institute, White Plains, NY, USA.,Feil Family Brain and Mind Research Institute, Department of Neurology and Neuroscience, Weill Medical College, Cornell University, New York, NY, USA
| | - R R Ratan
- Burke-Cornell Medical Research Institute, White Plains, NY, USA.,Feil Family Brain and Mind Research Institute, Department of Neurology and Neuroscience, Weill Medical College, Cornell University, New York, NY, USA
| | - C Culmsee
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Fachbereich Pharmazie, Philipps-Universität Marburg, Karl-von-Frisch-Straße 1, Marburg 35032, Germany
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14
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Montalbano R, Honrath B, Wissniowski TT, Elxnat M, Roth S, Ocker M, Quint K, Churin Y, Roederfeld M, Schroeder D, Glebe D, Roeb E, Fazio PD. Exogenous hepatitis B virus envelope proteins induce endoplasmic reticulum stress: involvement of cannabinoid axis in liver cancer cells. Oncotarget 2016; 7:20312-23. [PMID: 26967385 PMCID: PMC4991457 DOI: 10.18632/oncotarget.7950] [Citation(s) in RCA: 31] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 02/13/2016] [Indexed: 02/07/2023] Open
Abstract
HBV represents the most common chronic viral infection and major cause of hepatocellular carcinoma (HCC), although its exact role in liver tumorigenesis is unclear. Massive storage of the small (SHBs), middle (MHBs) and large surface (LHBs) HBV envelope proteins leads to cell stress and sustained inflammatory responses. Cannabinoid (CB) system is involved in the pathogenesis of liver diseases, stimulating acute and chronic inflammation, liver damage and fibrogenesis; it triggers endoplasmic reticulum (ER) stress response. The aim of our work was to investigate the activation of ER stress pathway after ectopic HBV envelope proteins expression, in liver cancer cells, and the role exerted by CB receptors. PCR, immunofluorescence and western blotting showed that exogenous LHBs and MHBs induce a clear ER stress response in Huh-7 cells expressing CB1 receptor. Up-regulation of the chaperone BiP/GRP78 (Binding Immunoglobulin Protein/Glucose-Regulated Protein 78) and of the transcription factor CHOP/GADD153 (C/EBP Homologous Protein/Growth Arrest and DNA Damage inducible gene 153), phosphorylation of PERK (PKR-like ER Kinase) and eIF2α (Eukaryotic Initiation Factor 2α) and splicing of XBP1 (X-box binding protein 1) was observed. CB1-/- HepG2 cells did not show any ER stress activation. Inhibition of CB1 receptor counteracted BiP expression in transfected Huh-7 and in HBV+ PLC/PRF/5 cells; whereas no effect was observed in HBV- HLF cells. These results suggest that HBV envelope proteins are able to induce the ER stress pathway. CB1 expression is directly correlated with ER stress function. Further investigations are needed to clarify the involvement of cannabinoid in HCC progression after HBV infection.
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Affiliation(s)
- Roberta Montalbano
- 1 Department of Visceral, Thoracic and Vascular Surgery, Philipps University of Marburg, Marburg, Germany
| | - Birgit Honrath
- 1 Department of Visceral, Thoracic and Vascular Surgery, Philipps University of Marburg, Marburg, Germany
| | | | - Moritz Elxnat
- 1 Department of Visceral, Thoracic and Vascular Surgery, Philipps University of Marburg, Marburg, Germany
| | - Silvia Roth
- 1 Department of Visceral, Thoracic and Vascular Surgery, Philipps University of Marburg, Marburg, Germany
| | - Matthias Ocker
- 3 Institute for Surgical Research, Philipps University of Marburg, Marburg, Germany
- 6 Present address: Department of Gastroenterology CBF, Charité University Medicine Berlin and Bayer Pharma AG, Experimental Medicine Oncology, Berlin, Germany
| | - Karl Quint
- 3 Institute for Surgical Research, Philipps University of Marburg, Marburg, Germany
| | - Yuri Churin
- 4 Department of Gastroenterology, Justus Liebig University, Giessen, Germany
| | - Martin Roederfeld
- 4 Department of Gastroenterology, Justus Liebig University, Giessen, Germany
| | - Dirk Schroeder
- 4 Department of Gastroenterology, Justus Liebig University, Giessen, Germany
| | - Dieter Glebe
- 5 Institute of Medical Virology, National Reference Centre for Hepatitis B and D Viruses, Justus Liebig University, Giessen, Germany
| | - Elke Roeb
- 4 Department of Gastroenterology, Justus Liebig University, Giessen, Germany
| | - Pietro Di Fazio
- 1 Department of Visceral, Thoracic and Vascular Surgery, Philipps University of Marburg, Marburg, Germany
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15
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Richter M, Vidovic N, Honrath B, Mahavadi P, Dodel R, Dolga AM, Culmsee C. Activation of SK2 channels preserves ER Ca²⁺ homeostasis and protects against ER stress-induced cell death. Cell Death Differ 2015; 23:814-27. [PMID: 26586570 DOI: 10.1038/cdd.2015.146] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/03/2015] [Accepted: 09/21/2015] [Indexed: 01/24/2023] Open
Abstract
Alteration of endoplasmic reticulum (ER) Ca(2+) homeostasis leads to excessive cytosolic Ca(2+) accumulation and delayed neuronal cell death in acute and chronic neurodegenerative disorders. While our recent studies established a protective role for SK channels against excessive intracellular Ca(2+) accumulation, their functional role in the ER has not been elucidated yet. We show here that SK2 channels are present in ER membranes of neuronal HT-22 cells, and that positive pharmacological modulation of SK2 channels with CyPPA protects against cell death induced by the ER stressors brefeldin A and tunicamycin. Calcium imaging of HT-22 neurons revealed that elevated cytosolic Ca(2+) levels and decreased ER Ca(2+) load during sustained ER stress could be largely prevented by SK2 channel activation. Interestingly, SK2 channel activation reduced the amount of the unfolded protein response transcription factor ATF4, but further enhanced the induction of CHOP. Using siRNA approaches we confirmed a detrimental role for ATF4 in ER stress, whereas CHOP regulation was dispensable for both, brefeldin A toxicity and CyPPA-mediated protection. Cell death induced by blocking Ca(2+) influx into the ER with the SERCA inhibitor thapsigargin was not prevented by CyPPA. Blocking the K(+) efflux via K(+)/H(+) exchangers with quinine inhibited CyPPA-mediated neuroprotection, suggesting an essential role of proton uptake and K(+) release in the SK channel-mediated neuroprotection. Our data demonstrate that ER SK2 channel activation preserves ER Ca(2+) uptake and retention which determines cell survival in conditions where sustained ER stress contributes to progressive neuronal death.
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Affiliation(s)
- M Richter
- Institute for Pharmacology and Clinical Pharmacy, Philipps-University Marburg, Marburg, Germany.,Department of Neurology, Philipps-University Marburg, Marburg, Germany
| | - N Vidovic
- Department of Neurology, Philipps-University Marburg, Marburg, Germany
| | - B Honrath
- Institute for Pharmacology and Clinical Pharmacy, Philipps-University Marburg, Marburg, Germany
| | - P Mahavadi
- Department of Internal Medicine, Justus-Liebig-University, Giessen, Germany.,Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - R Dodel
- Department of Neurology, Philipps-University Marburg, Marburg, Germany
| | - A M Dolga
- Institute for Pharmacology and Clinical Pharmacy, Philipps-University Marburg, Marburg, Germany.,Faculty of Mathematics and Natural Sciences, Molecular Pharmacology - Groningen Research Institute of Pharmacy, Groningen, The Netherlands
| | - C Culmsee
- Institute for Pharmacology and Clinical Pharmacy, Philipps-University Marburg, Marburg, Germany
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