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Kirchner MK, Althammer F, Campos-Lira E, Montanez J, Stern JE. Endoplasmic Reticulum and Mitochondrial Calcium Handling Dynamically Shape Slow Afterhyperpolarizations in Vasopressin Magnocellular Neurons. J Neurosci 2024; 44:e0003242024. [PMID: 38937101 PMCID: PMC11270521 DOI: 10.1523/jneurosci.0003-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 05/15/2024] [Accepted: 06/10/2024] [Indexed: 06/29/2024] Open
Abstract
Many neurons including vasopressin (VP) magnocellular neurosecretory cells (MNCs) of the hypothalamic supraoptic nucleus (SON) generate afterhyperpolarizations (AHPs) during spiking to slow firing, a phenomenon known as spike frequency adaptation. The AHP is underlain by Ca2+-activated K+ currents, and while slow component (sAHP) features are well described, its mechanism remains poorly understood. Previous work demonstrated that Ca2+ influx through N-type Ca2+ channels is a primary source of sAHP activation in SON oxytocin neurons, but no obvious channel coupling was described for VP neurons. Given this, we tested the possibility of an intracellular source of sAHP activation, namely, the Ca2+-handling organelles endoplasmic reticulum (ER) and mitochondria in male and female Wistar rats. We demonstrate that ER Ca2+ depletion greatly inhibits sAHPs without a corresponding decrease in Ca2+ signal. Caffeine sensitized AHP activation by Ca2+ In contrast to ER, disabling mitochondria with CCCP or blocking mitochondria Ca2+ uniporters (MCUs) enhanced sAHP amplitude and duration, implicating mitochondria as a vital buffer for sAHP-activating Ca2+ Block of mitochondria Na+-dependent Ca2+ release via triphenylphosphonium (TPP+) failed to affect sAHPs, indicating that mitochondria Ca2+ does not contribute to sAHP activation. Together, our results suggests that ER Ca2+-induced Ca2+ release activates sAHPs and mitochondria shape the spatiotemporal trajectory of the sAHP via Ca2+ buffering in VP neurons. Overall, this implicates organelle Ca2+, and specifically ER-mitochondria-associated membrane contacts, as an important site of Ca2+ microdomain activity that regulates sAHP signaling pathways. Thus, this site plays a major role in influencing VP firing activity and systemic hormonal release.
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Affiliation(s)
- Matthew K Kirchner
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Ferdinand Althammer
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Elba Campos-Lira
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Juliana Montanez
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Javier E Stern
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
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McCarthy CI, Kavalali ET. Nano-organization of synaptic calcium signaling. Biochem Soc Trans 2024; 52:1459-1471. [PMID: 38752834 DOI: 10.1042/bst20231385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/17/2024] [Accepted: 05/03/2024] [Indexed: 06/27/2024]
Abstract
Recent studies suggest an exquisite structural nano-organization within single synapses, where sites of evoked fusion - marked by clustering of synaptic vesicles, active zone proteins and voltage-gated calcium channels - are directly juxtaposed to postsynaptic receptor clusters within nanocolumns. This direct nanometer scale alignment between presynaptic fusion apparatus and postsynaptic receptors is thought to ensure the fidelity of synaptic signaling and possibly allow multiple distinct signals to occur without interference from each other within a single active zone. The functional specificity of this organization is made possible by the inherent nano-organization of calcium signals, where all the different calcium sources such as voltage-gated calcium channels, intracellular stores and store-operated calcium entry have dedicated local targets within their nanodomain to ensure precision of action. Here, we discuss synaptic nano-organization from the perspective of calcium signals, where some of the principal findings from early work in the 1980s continue to inspire current studies that exploit new genetic tools and super-resolution imaging technologies.
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Affiliation(s)
- Clara I McCarthy
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
| | - Ege T Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
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3
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Bertagna F, Ahmad S, Lewis R, Silva SRP, McFadden J, Huang CLH, Matthews HR, Jeevaratnam K. Loose-patch clamp analysis applied to voltage-gated ionic currents following pharmacological ryanodine receptor modulation in murine hippocampal cornu ammonis-1 pyramidal neurons. Front Physiol 2024; 15:1359560. [PMID: 38720787 PMCID: PMC11076846 DOI: 10.3389/fphys.2024.1359560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/04/2024] [Indexed: 05/12/2024] Open
Abstract
Introduction The loose-patch clamp technique was first developed and used in native amphibian skeletal muscle (SkM), offering useful features complementing conventional sharp micro-electrode, gap, or conventional patch voltage clamping. It demonstrated the feedback effects of pharmacological modification of ryanodine receptor (RyR)-mediated Ca2+ release on the Na+ channel (Nav1.4) currents, initiating excitation-contraction coupling in native murine SkM. The effects of the further RyR and Ca2+-ATPase (SERCA) antagonists, dantrolene and cyclopiazonic acid (CPA), additionally implicated background tubular-sarcoplasmic Ca2+ domains in these actions. Materials and methods We extend the loose-patch clamp approach to ion current measurements in murine hippocampal brain slice cornu ammonis-1 (CA1) pyramidal neurons. We explored the effects on Na+ currents of pharmacologically manipulating RyR and SERCA-mediated intracellular store Ca2+ release and reuptake. We adopted protocols previously applied to native skeletal muscle. These demonstrated Ca2+-mediated feedback effects on the Na+ channel function. Results Experiments applying depolarizing 15 ms duration loose-patch clamp steps to test voltages ranging from -40 to 120 mV positive to the resting membrane potential demonstrated that 0.5 mM caffeine decreased inward current amplitudes, agreeing with the previous SkM findings. It also decreased transient but not prolonged outward current amplitudes. However, 2 mM caffeine affected neither inward nor transient outward but increased prolonged outward currents, in contrast to its increasing inward currents in SkM. Furthermore, similarly and in contrast to previous SkM findings, both dantrolene (10 μM) and CPA (1 μM) pre-administration left both inward and outward currents unchanged. Nevertheless, dantrolene pretreatment still abrogated the effects of subsequent 0.5- and 2-mM caffeine challenges on both inward and outward currents. Finally, CPA abrogated the effects of 0.5 mM caffeine on both inward and outward currents, but with 2 mM caffeine, inward and transient outward currents were unchanged, but sustained outward currents increased. Conclusion We, thus, extend loose-patch clamping to establish pharmacological properties of murine CA1 pyramidal neurons and their similarities and contrasts with SkM. Here, evoked though not background Ca2+-store release influenced Nav and Kv excitation, consistent with smaller contributions of background store Ca2+ release to resting [Ca2+]. This potential non-canonical mechanism could modulate neuronal membrane excitability or cellular firing rates.
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Affiliation(s)
- Federico Bertagna
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, United Kingdom
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Shiraz Ahmad
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Rebecca Lewis
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, United Kingdom
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - S. Ravi P. Silva
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, United Kingdom
- Advanced Technology Institute, University of Surrey, Guildford, United Kingdom
| | - Johnjoe McFadden
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, United Kingdom
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Christopher L.-H. Huang
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Hugh R. Matthews
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Kamalan Jeevaratnam
- Leverhulme Quantum Biology Doctoral Training Centre, University of Surrey, Guildford, United Kingdom
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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4
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Torres R, Hidalgo C. Subcellular localization and transcriptional regulation of brain ryanodine receptors. Functional implications. Cell Calcium 2023; 116:102821. [PMID: 37949035 DOI: 10.1016/j.ceca.2023.102821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/16/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
Ryanodine receptors (RyR) are intracellular Ca2+ channels localized in the endoplasmic reticulum, where they act as critical mediators of Ca2+-induced Ca2+ calcium release (CICR). In the brain, mammals express in both neurons, and non-neuronal cells, a combination of the three RyR-isoforms (RyR1-3). Pharmacological approaches, which do not distinguish between isoforms, have indicated that RyR-isoforms contribute to brain function. However, isoform-specific manipulations have revealed that RyR-isoforms display different subcellular localizations and are differentially associated with neuronal function. These findings raise the need to understand RyR-isoform specific transcriptional regulation, as this knowledge will help to elucidate the causes of neuronal dysfunction for a growing list of brain disorders that show altered RyR channel expression and function.
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Affiliation(s)
- Rodrigo Torres
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Lago Panguipulli 1390, 5501842, Puerto Montt, Chile.
| | - Cecilia Hidalgo
- Department of Neurosciences. Biomedical Neuroscience Institute, Physiology and Biophysics Program, Institute of Biomedical Sciences, Center for Exercise, Metabolism and Cancer Studies, Faculty of Medicine, Universidad de Chile, Santiago, 8380000, Chile
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Lan Y, Zou S, Wang W, Chen Q, Zhu Y. Progress in cancer neuroscience. MedComm (Beijing) 2023; 4:e431. [PMID: 38020711 PMCID: PMC10665600 DOI: 10.1002/mco2.431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/02/2023] [Accepted: 11/08/2023] [Indexed: 12/01/2023] Open
Abstract
Cancer of the central nervous system (CNS) can crosstalk systemically and locally in the tumor microenvironment and has become a topic of attention for tumor initiation and advancement. Recently studied neuronal and cancer interaction fundamentally altered the knowledge about glioma and metastases, indicating how cancers invade complex neuronal networks. This review systematically discussed the interactions between neurons and cancers and elucidates new therapeutic avenues. We have overviewed the current understanding of direct or indirect communications of neuronal cells with cancer and the mechanisms associated with cancer invasion. Besides, tumor-associated neuronal dysfunction and the influence of cancer therapies on the CNS are highlighted. Furthermore, interactions between peripheral nervous system and various cancers have also been discussed separately. Intriguingly and importantly, it cannot be ignored that exosomes could mediate the "wireless communications" between nervous system and cancer. Finally, promising future strategies targeting neuronal-brain tumor interactions were reviewed. A great deal of work remains to be done to elucidate the neuroscience of cancer, and future more research should be directed toward clarifying the precise mechanisms of cancer neuroscience, which hold enormous promise to improve outcomes for a wide range of malignancies.
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Affiliation(s)
- Yu‐Long Lan
- Department of NeurosurgerySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
- Key Laboratory of Precise Treatment and Clinical Translational Research of Neurological DiseasesHangzhouZhejiangChina
- Clinical Research Center for Neurological Diseases of Zhejiang ProvinceHangzhouChina
| | - Shuang Zou
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical ScienceZhejiang Chinese Medical UniversityHangzhouChina
| | - Wen Wang
- Department of NeurosurgeryBeijing Tiantan Hospital, Capital Medical UniversityBeijingChina
| | - Qi Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical ScienceZhejiang Chinese Medical UniversityHangzhouChina
| | - Yongjian Zhu
- Department of NeurosurgerySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
- Key Laboratory of Precise Treatment and Clinical Translational Research of Neurological DiseasesHangzhouZhejiangChina
- Clinical Research Center for Neurological Diseases of Zhejiang ProvinceHangzhouChina
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Parkkinen I, Their A, Asghar MY, Sree S, Jokitalo E, Airavaara M. Pharmacological Regulation of Endoplasmic Reticulum Structure and Calcium Dynamics: Importance for Neurodegenerative Diseases. Pharmacol Rev 2023; 75:959-978. [PMID: 37127349 DOI: 10.1124/pharmrev.122.000701] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 03/27/2023] [Accepted: 04/04/2023] [Indexed: 05/03/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest organelle of the cell, composed of a continuous network of sheets and tubules, and is involved in protein, calcium (Ca2+), and lipid homeostasis. In neurons, the ER extends throughout the cell, both somal and axodendritic compartments, and is highly important for neuronal functions. A third of the proteome of a cell, secreted and membrane-bound proteins, are processed within the ER lumen and most of these proteins are vital for neuronal activity. The brain itself is high in lipid content, and many structural lipids are produced, in part, by the ER. Cholesterol and steroid synthesis are strictly regulated in the ER of the blood-brain barrier protected brain cells. The high Ca2+ level in the ER lumen and low cytosolic concentration is needed for Ca2+-based intracellular signaling, for synaptic signaling and Ca2+ waves, and for preparing proteins for correct folding in the presence of high Ca2+ concentrations to cope with the high concentrations of extracellular milieu. Particularly, ER Ca2+ is controlled in axodendritic areas for proper neurito- and synaptogenesis and synaptic plasticity and remodeling. In this review, we cover the physiologic functions of the neuronal ER and discuss it in context of common neurodegenerative diseases, focusing on pharmacological regulation of ER Ca2+ Furthermore, we postulate that heterogeneity of the ER, its protein folding capacity, and ensuring Ca2+ regulation are crucial factors for the aging and selective vulnerability of neurons in various neurodegenerative diseases. SIGNIFICANCE STATEMENT: Endoplasmic reticulum (ER) Ca2+ regulators are promising therapeutic targets for degenerative diseases for which efficacious drug therapies do not exist. The use of pharmacological probes targeting maintenance and restoration of ER Ca2+ can provide restoration of protein homeostasis (e.g., folding of complex plasma membrane signaling receptors) and slow down the degeneration process of neurons.
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Affiliation(s)
- Ilmari Parkkinen
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Anna Their
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Muhammad Yasir Asghar
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Sreesha Sree
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Eija Jokitalo
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Mikko Airavaara
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
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7
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Valdés-Undurraga I, Lobos P, Sánchez-Robledo V, Arias-Cavieres A, SanMartín CD, Barrientos G, More J, Muñoz P, Paula-Lima AC, Hidalgo C, Adasme T. Long-term potentiation and spatial memory training stimulate the hippocampal expression of RyR2 calcium release channels. Front Cell Neurosci 2023; 17:1132121. [PMID: 37025696 PMCID: PMC10071512 DOI: 10.3389/fncel.2023.1132121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/21/2023] [Indexed: 04/08/2023] Open
Abstract
Introduction: Neuronal Ca2+ signals generated through the activation of Ca2+-induced Ca2+ release in response to activity-generated Ca2+ influx play a significant role in hippocampal synaptic plasticity, spatial learning, and memory. We and others have previously reported that diverse stimulation protocols, or different memory-inducing procedures, enhance the expression of endoplasmic reticulum-resident Ca2+ release channels in rat primary hippocampal neuronal cells or hippocampal tissue. Methods and Results: Here, we report that induction of long-term potentiation (LTP) by Theta burst stimulation protocols of the CA3-CA1 hippocampal synapse increased the mRNA and protein levels of type-2 Ryanodine Receptor (RyR2) Ca2+ release channels in rat hippocampal slices. Suppression of RyR channel activity (1 h preincubation with 20 μM ryanodine) abolished both LTP induction and the enhanced expression of these channels; it also promoted an increase in the surface expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR1 and GluR2 and caused a moderate but significant reduction of dendritic spine density. In addition, training rats in the Morris water maze induced memory consolidation, which lasted for several days after the end of the training period, accompanied by an increase in the mRNA levels and the protein content of the RyR2 channel isoform. Discussion: We confirm in this work that LTP induction by TBS protocols requires functional RyR channels. We propose that the increments in the protein content of RyR2 Ca2+ release channels, induced by LTP or spatial memory training, play a significant role in hippocampal synaptic plasticity and spatial memory consolidation.
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Affiliation(s)
- Ismael Valdés-Undurraga
- Biomedical Research Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- IVIRMA, Santiago, Chile
| | - Pedro Lobos
- Biomedical Research Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Center for Advanced Clinical Investigation (CICA), Clinical Hospital, Universidad de Chile, Santiago, Chile
| | | | - Alejandra Arias-Cavieres
- Section of Emergency Medicine, Department of Medicine, Institute for Integrative Physiology, Neuroscience Institute, The University of Chicago, Chicago, IL, United States
| | - Carol D. SanMartín
- Center for Advanced Clinical Investigation (CICA), Clinical Hospital, Universidad de Chile, Santiago, Chile
| | - Genaro Barrientos
- Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Jamileth More
- Center for Advanced Clinical Investigation (CICA), Clinical Hospital, Universidad de Chile, Santiago, Chile
- Laboratory of Translational Psychiatry, Department of Neuroscience and Department de Psychiatry North, Universidad de Chile, Santiago, Chile
| | - Pablo Muñoz
- Translational Neurology Center and Biomedical Research Center, Faculty of Medicine, Universidad de Valparaíso, Valparaíso, Chile
| | - Andrea Cristina Paula-Lima
- Biomedical Research Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Institute for Research in Dental Sciences (ICOD), Faculty of Dentistry, Universidad de Chile, Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Biomedical Research Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Center for Exercise, Metabolism and Cancer (CEMC), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Tatiana Adasme
- Biomedical Research Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Section of Emergency Medicine, Department of Medicine, Institute for Integrative Physiology, Neuroscience Institute, The University of Chicago, Chicago, IL, United States
- Laboratory of Translational Psychiatry, Department of Neuroscience and Department de Psychiatry North, Universidad de Chile, Santiago, Chile
- *Correspondence: Tatiana Adasme
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8
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Shkryl VM. The spatio-temporal properties of calcium transients in hippocampal pyramidal neurons in vitro. Front Cell Neurosci 2022; 16:1054950. [PMID: 36589284 PMCID: PMC9795003 DOI: 10.3389/fncel.2022.1054950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/24/2022] [Indexed: 12/15/2022] Open
Abstract
The spatio-temporal properties of calcium signals were studied in cultured pyramidal neurons of the hippocampus using two-dimensional fluorescence microscopy and ratiometric dye Fura-2. Depolarization-induced Ca2+ transients revealed an asynchronous delayed increase in free Ca2+ concentration. We found that the level of free resting calcium in the cell nucleus is significantly lower compared to the soma, sub-membrane, and dendritic tree regions. Calcium release from the endoplasmic reticulum under the action of several stimuli (field stimulation, high K+ levels, and caffeine) occurs in all areas studied. Under depolarization, calcium signals developed faster in the dendrites than in other areas, while their amplitude was significantly lower since larger and slower responses inside the soma. The peak value of the calcium response to the application of 10 mM caffeine, ryanodine receptors (RyRs) agonist, does not differ in the sub-membrane zone, central region, and nucleus but significantly decreases in the dendrites. In the presence of caffeine, the delay of Ca2+ signals between various areas under depolarization significantly declined. Thirty percentage of the peak amplitude of Ca2+ transients at prolonged electric field stimulation corresponded to calcium release from the ER store by RyRs, while short-term stimulation did not depend on them. 20 μM dantrolene, RyRs inhibitor, significantly reduces Ca2+ transient under high K+ levels depolarization of the neuron. RyRs-mediated enhancement of the Ca2+ signal is more pronounced in the central part and nucleus compared to the sub-membrane or dendrites regions of the neuron. In summary, using the ratiometric imaging allowed us to obtain additional information about the involvement of RyRs in the intracellular dynamics of Ca2+ signals induced by depolarization or electrical stimulation train, with an underlying change in Ca2+ concentration in various regions of interest in hippocampal pyramidal neurons.
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9
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Vega-Vásquez I, Lobos P, Toledo J, Adasme T, Paula-Lima A, Hidalgo C. Hippocampal dendritic spines express the RyR3 but not the RyR2 ryanodine receptor isoform. Biochem Biophys Res Commun 2022; 633:96-103. [PMID: 36344175 DOI: 10.1016/j.bbrc.2022.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022]
Abstract
The hippocampus is a brain region implicated in synaptic plasticity and memory formation; both processes require neuronal Ca2+ signals generated by Ca2+ entry via plasma membrane Ca2+ channels and Ca2+ release from the endoplasmic reticulum (ER). Through Ca2+-induced Ca2+ release, the ER-resident ryanodine receptor (RyR) Ca2+ channels amplify and propagate Ca2+ entry signals, leading to activation of cytoplasmic and nuclear Ca2+-dependent signaling pathways required for synaptic plasticity and memory processes. Earlier reports have shown that mice and rat hippocampus expresses mainly the RyR2 isoform, with lower expression levels of the RyR3 isoform and almost undetectable levels of the RyR1 isoform; both the RyR2 and RyR3 isoforms have central roles in synaptic plasticity and hippocampal-dependent memory processes. Here, we describe that dendritic spines of rat primary hippocampal neurons express the RyR3 channel isoform, which is also expressed in the neuronal body and neurites. In contrast, the RyR2 isoform, which is widely expressed in the neuronal body and neurites of primary hippocampal neurons, is absent from the dendritic spines. We propose that this asymmetric distribution is of relevance for hippocampal neuronal function. We suggest that the RyR3 isoform amplifies activity-generated Ca2+ entry signals at postsynaptic dendritic spines, from where they propagate to the dendrite and activate primarily RyR2-mediated Ca2+ release, leading to Ca2+ signal propagation into the soma and the nucleus where they activate the expression of genes that mediate synaptic plasticity and memory.
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Affiliation(s)
- Ignacio Vega-Vásquez
- Biomedical Neuroscience Institute (BNI), Universidad de Chile, Independencia 1027, Santiago, Chile; Advanced Scientific Equipment Network (REDECA), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Pedro Lobos
- Biomedical Neuroscience Institute (BNI), Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Jorge Toledo
- Advanced Scientific Equipment Network (REDECA), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Tatiana Adasme
- Biomedical Neuroscience Institute (BNI), Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Andrea Paula-Lima
- Biomedical Neuroscience Institute (BNI), Universidad de Chile, Independencia 1027, Santiago, Chile; Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile; Institute for Research in Dental Sciences (ICOD), Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Interuniversity Center for Healthy Aging (CIES), Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute (BNI), Universidad de Chile, Independencia 1027, Santiago, Chile; Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile; Physiology and Biophysics Program, Institute of Biomedical Sciences (ICBM), Center for Exercise, Metabolism, and Cancer (CEMC), Faculty of Medicine, Universidad de Chile, Santiago, Chile.
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10
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Zampese E, Wokosin DL, Gonzalez-Rodriguez P, Guzman JN, Tkatch T, Kondapalli J, Surmeier WC, D’Alessandro KB, De Stefani D, Rizzuto R, Iino M, Molkentin JD, Chandel NS, Schumacker PT, Surmeier DJ. Ca 2+ channels couple spiking to mitochondrial metabolism in substantia nigra dopaminergic neurons. SCIENCE ADVANCES 2022; 8:eabp8701. [PMID: 36179023 PMCID: PMC9524841 DOI: 10.1126/sciadv.abp8701] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/12/2022] [Indexed: 05/08/2023]
Abstract
How do neurons match generation of adenosine triphosphate by mitochondria to the bioenergetic demands of regenerative activity? Although the subject of speculation, this coupling is still poorly understood, particularly in neurons that are tonically active. To help fill this gap, pacemaking substantia nigra dopaminergic neurons were studied using a combination of optical, electrophysiological, and molecular approaches. In these neurons, spike-activated calcium (Ca2+) entry through Cav1 channels triggered Ca2+ release from the endoplasmic reticulum, which stimulated mitochondrial oxidative phosphorylation through two complementary Ca2+-dependent mechanisms: one mediated by the mitochondrial uniporter and another by the malate-aspartate shuttle. Disrupting either mechanism impaired the ability of dopaminergic neurons to sustain spike activity. While this feedforward control helps dopaminergic neurons meet the bioenergetic demands associated with sustained spiking, it is also responsible for their elevated oxidant stress and possibly to their decline with aging and disease.
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Affiliation(s)
- Enrico Zampese
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - David L. Wokosin
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Patricia Gonzalez-Rodriguez
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Jaime N. Guzman
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Tatiana Tkatch
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Jyothisri Kondapalli
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - William C. Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Karis B. D’Alessandro
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Masamitsu Iino
- Department of Physiology, Nihon University School of Medicine, 30-1, Oyaguchi Kami-cho, Itabashi-ku, Tokyo 173-8610, Japan
| | - Jeffery D. Molkentin
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Navdeep S. Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Paul T. Schumacker
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - D. James Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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11
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Paschou M, Papazafiri P, Charalampous C, Zachariadis M, Dedos SG, Doxakis E. Neuronal microRNAs safeguard ER Ca 2+ homeostasis and attenuate the unfolded protein response upon stress. Cell Mol Life Sci 2022; 79:373. [PMID: 35727337 PMCID: PMC11073139 DOI: 10.1007/s00018-022-04398-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 04/23/2022] [Accepted: 05/21/2022] [Indexed: 11/30/2022]
Abstract
Ca2+ is a critical mediator of neurotransmitter release, synaptic plasticity, and gene expression, but also excitotoxicity. Ca2+ signaling and homeostasis are coordinated by an intricate network of channels, pumps, and calcium-binding proteins, which must be rapidly regulated at all expression levels. Τhe role of neuronal miRNAs in regulating ryanodine receptors (RyRs) and inositol 1,4,5-triphosphate receptors (IP3Rs) was investigated to understand the underlying mechanisms that modulate ER Ca2+ release. RyRs and IP3Rs are critical in mounting and propagating cytosolic Ca2+ signals by functionally linking the ER Ca2+ content, while excessive ER Ca2+ release via these receptors is central to the pathophysiology of a wide range of neurological diseases. Herein, two brain-restricted microRNAs, miR-124-3p and miR-153-3p, were found to bind to RyR1-3 and IP3R3 3'UTRs, and suppress their expression at both the mRNA and protein level. Ca2+ imaging studies revealed that overexpression of these miRNAs reduced ER Ca2+ release upon RyR/IP3R activation, but had no effect on [Ca2+]i under resting conditions. Interestingly, treatments that cause excessive ER Ca2+ release decreased expression of these miRNAs and increased expression of their target ER Ca2+ channels, indicating interdependence of miRNAs, RyRs, and IP3Rs in Ca2+ homeostasis. Furthermore, by maintaining the ER Ca2+ content, miR-124 and miR-153 reduced cytosolic Ca2+ overload and preserved protein-folding capacity by attenuating PERK signaling. Overall, this study shows that miR-124-3p and miR-153-3p fine-tune ER Ca2+ homeostasis and alleviate ER stress responses.
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Affiliation(s)
- Maria Paschou
- Center for Basic Research, Biomedical Research Foundation, Academy of Athens (BRFAA), Soranou Efesiou 4, 11527, Athens, Greece
- Department of Biology, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis, 15784, Athens, Greece
| | - Panagiota Papazafiri
- Department of Biology, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis, 15784, Athens, Greece
| | - Chrysanthi Charalampous
- Center for Basic Research, Biomedical Research Foundation, Academy of Athens (BRFAA), Soranou Efesiou 4, 11527, Athens, Greece
| | - Michael Zachariadis
- Department of Biology, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis, 15784, Athens, Greece
- Material and Chemical Characterization Facility (MC2), Faculty of Science, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Skarlatos G Dedos
- Department of Biology, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis, 15784, Athens, Greece.
| | - Epaminondas Doxakis
- Center for Basic Research, Biomedical Research Foundation, Academy of Athens (BRFAA), Soranou Efesiou 4, 11527, Athens, Greece.
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12
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Zhang W, Ye F, Pang N, Kessi M, Xiong J, Chen S, Peng J, Yang L, Yin F. Restoration of Sarco/Endoplasmic Reticulum Ca 2+-ATPase Activity Functions as a Pivotal Therapeutic Target of Anti-Glutamate-Induced Excitotoxicity to Attenuate Endoplasmic Reticulum Ca 2+ Depletion. Front Pharmacol 2022; 13:877175. [PMID: 35517826 PMCID: PMC9065279 DOI: 10.3389/fphar.2022.877175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Glutamate-induced excitotoxicity is a pathological basis of many acute/chronic neurodegenerative diseases. Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2b) is a membrane-embedded P-type ATPase pump that manages the translocation of calcium ions (Ca2+) from cytosol into the lumen of the endoplasmic reticulum (ER) calcium stores. It participates in a wide range of biological functions in the central nervous system (CNS). However, the role of SERCA2b in glutamate-induced excitotoxicity and its mechanism must be elucidated. Herein, we demonstrate that SERCA2b mutants exacerbate the excitotoxicity of hypo-glutamate stimulation on HT22 cells. In this study, SERCA2b mutants accelerated Ca2+ depletion through loss-of-function (reduced pumping capacity) or gain-of-function (acquired leakage), resulting in ER stress. In addition, the occurrence of ER Ca2+ depletion increased mitochondria-associated membrane formation, which led to mitochondrial Ca2+ overload and dysfunction. Moreover, the enhancement of SERCA2b pumping capacity or inhibition of Ca2+ leakage attenuated Ca2+ depletion and impeded excitotoxicity in response to hypo-glutamate stimulation. In conclusion, SERCA2b mutants exacerbate ER Ca2+-depletion-mediated excitotoxicity in glutamate-sensitive HT22 cells. The mechanism of disruption is mainly related to the heterogeneity of SERCA2b mutation sites. Stabilization of SRECA2b function is a critical therapeutic approach against glutamate-induced excitotoxicity. These data will expand understanding of organelle regulatory networks and facilitate the discovery and creation of drugs against excitatory/inhibitory imbalance in the CNS.
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Affiliation(s)
- Wen Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Fanghua Ye
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Nan Pang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Miriam Kessi
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China.,Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Shimeng Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Li Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Pediatrics, Changsha, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
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13
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Venkataramani V, Tanev DI, Kuner T, Wick W, Winkler F. Synaptic input to brain tumors: clinical implications. Neuro Oncol 2021; 23:23-33. [PMID: 32623467 DOI: 10.1093/neuonc/noaa158] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The recent discovery of synaptic connections between neurons and brain tumor cells fundamentally challenges our understanding of gliomas and brain metastases and shows how these tumors can integrate into complex neuronal circuits. Here, we provide an overview of glutamatergic neuron-to-brain tumor synaptic communication (NBTSC) and explore novel therapeutic avenues. First, we summarize current concepts of direct synaptic interactions between presynaptic neurons and postsynaptic glioma cells, and indirect perisynaptic input to metastatic breast cancer cells. We explain how these novel structures drive brain tumor growth and invasion. Second, a vicious cycle of enhanced neuronal activity, including tumor-related epilepsy, and glioma progression is described. Finally, we discuss which future avenues to target NBTSC appear most promising. All in all, further characterization of NBTSC and the exploration of NBTSC-inhibiting therapies have the potential to reveal critical vulnerabilities of yet incurable brain tumors.
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Affiliation(s)
- Varun Venkataramani
- Neurology Clinic and National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany
- Clinical Cooperation Unit Neuro-Oncology, German Cancer Consortium, German Cancer Research Center, Heidelberg, Germany
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Dimitar Ivanov Tanev
- Neurology Clinic and National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany
- Clinical Cooperation Unit Neuro-Oncology, German Cancer Consortium, German Cancer Research Center, Heidelberg, Germany
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Wolfgang Wick
- Neurology Clinic and National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany
- Clinical Cooperation Unit Neuro-Oncology, German Cancer Consortium, German Cancer Research Center, Heidelberg, Germany
| | - Frank Winkler
- Neurology Clinic and National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany
- Clinical Cooperation Unit Neuro-Oncology, German Cancer Consortium, German Cancer Research Center, Heidelberg, Germany
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14
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Pereira-Figueiredo D, Nascimento AA, Cunha-Rodrigues MC, Brito R, Calaza KC. Caffeine and Its Neuroprotective Role in Ischemic Events: A Mechanism Dependent on Adenosine Receptors. Cell Mol Neurobiol 2021; 42:1693-1725. [PMID: 33730305 DOI: 10.1007/s10571-021-01077-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/05/2021] [Indexed: 02/07/2023]
Abstract
Ischemia is characterized by a transient, insufficient, or permanent interruption of blood flow to a tissue, which leads to an inadequate glucose and oxygen supply. The nervous tissue is highly active, and it closely depends on glucose and oxygen to satisfy its metabolic demand. Therefore, ischemic conditions promote cell death and lead to a secondary wave of cell damage that progressively spreads to the neighborhood areas, called penumbra. Brain ischemia is one of the main causes of deaths and summed with retinal ischemia comprises one of the principal reasons of disability. Although several studies have been performed to investigate the mechanisms of damage to find protective/preventive interventions, an effective treatment does not exist yet. Adenosine is a well-described neuromodulator in the central nervous system (CNS), and acts through four subtypes of G-protein-coupled receptors. Adenosine receptors, especially A1 and A2A receptors, are the main targets of caffeine in daily consumption doses. Accordingly, caffeine has been greatly studied in the context of CNS pathologies. In fact, adenosine system, as well as caffeine, is involved in neuroprotection effects in different pathological situations. Therefore, the present review focuses on the role of adenosine/caffeine in CNS, brain and retina, ischemic events.
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Affiliation(s)
- D Pereira-Figueiredo
- Neurobiology of the Retina Laboratory, Biomedical Sciences Program, Biomedical Institute, Fluminense Federal University, Niterói, RJ, Brazil
| | - A A Nascimento
- Neurobiology of the Retina Laboratory, Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil
| | - M C Cunha-Rodrigues
- Neurobiology of the Retina Laboratory, Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil
| | - R Brito
- Laboratory of Neuronal Physiology and Pathology, Cellular and Molecular Biology Department, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil
| | - K C Calaza
- Neurobiology of the Retina Laboratory, Biomedical Sciences Program, Biomedical Institute, Fluminense Federal University, Niterói, RJ, Brazil. .,Neurobiology of the Retina Laboratory, Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil. .,Neurobiology Department, Biology Institute of Fluminense Federal University, Niteroi, RJ, Brazil.
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15
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Rivero-Echeto MC, Perissinotti PP, González-Inchauspe C, Kargieman L, Bisagno V, Urbano FJ. Simultaneous administration of cocaine and caffeine dysregulates HCN and T-type channels. Psychopharmacology (Berl) 2021; 238:787-810. [PMID: 33241481 PMCID: PMC7688300 DOI: 10.1007/s00213-020-05731-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022]
Abstract
RATIONALE The abuse of psychostimulants has adverse consequences on the physiology of the central nervous system. In Argentina, and other South American countries, coca paste or "PACO" (cocaine and caffeine are its major components) is massively consumed with deleterious clinical consequences for the health and well-being of the general population. A scant number of studies have addressed the consequences of stimulant combination of cocaine and caffeine on the physiology of the somatosensory thalamocortical (ThCo) system. OBJECTIVES Our aim was to study ion conductances that have important implications regulating sleep-wake states 24-h after an acute or chronic binge-like administration of a cocaine and caffeine mixture following previously analyzed pasta base samples ("PACO"-like binge") using mice. METHODS We randomly injected (i.p.) male C57BL/6JFcen mice with a binge-like psychostimulants regimen during either 1 day (acute) or 1 day on/1 day off during 13 days for a total of 7 binges (chronic). Single-cell patch-clamp recordings of VB neurons were performed in thalamocortical slices 24 h after the last psychostimulant injection. We also recorded EEG/EMG from mice 24 h after being systemically treated with chronic administration of cocaine + caffeine versus saline, vehicle. RESULTS Our results showed notorious changes in the intrinsic properties of the VB nucleus neurons that persist after 24-h of either acute or chronic binge administrations of combined cocaine and caffeine ("PACO"-like binge). Functional dysregulation of HCN (hyperpolarization-activated cyclic nucleotide-gated) and T-type VGC (voltage-gated calcium) channels was described 24-h after acute/chronic "PACO"-like administrations. Furthermore, intracellular basal [Ca2+] disturbances resulted a key factor that modulated the availability and the activation of T-type channels, altering T-type "window currents." As a result, all these changes ultimately shaped the low-threshold spikes (LTS)-associated Ca2+ transients, regulated the membrane excitability, and altered sleep-wake transitions. CONCLUSION Our results suggest that deleterious consequences of stimulants cocaine and caffeine combination on the thalamocortical physiology as a whole might be related to potential neurotoxic effects of soaring intracellular [Ca2+].
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Affiliation(s)
- María Celeste Rivero-Echeto
- grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Ciudad de Buenos Aires, Argentina
| | - Paula P. Perissinotti
- grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Ciudad de Buenos Aires, Argentina
| | - Carlota González-Inchauspe
- grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Ciudad de Buenos Aires, Argentina
| | - Lucila Kargieman
- grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Ciudad de Buenos Aires, Argentina
| | - Verónica Bisagno
- grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Farmacológicas (ININFA), Ciudad de Buenos Aires, Argentina
| | - Francisco J. Urbano
- grid.7345.50000 0001 0056 1981CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Ciudad de Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular “Dr. Héctor Maldonado”, Ciudad de Buenos Aires, Argentina ,grid.7345.50000 0001 0056 1981IFIBYNE (UBA-CONICET), Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA Ciudad Autónoma de Buenos Aires, Argentina
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16
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Neuron-derived factors negatively modulate ryanodine receptor-mediated calcium release in cultured mouse astrocytes. Cell Calcium 2020; 92:102304. [PMID: 33065384 DOI: 10.1016/j.ceca.2020.102304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 12/22/2022]
Abstract
Changes in intracellular Ca2+ concentration ([Ca2+]i) produced by ryanodine receptor (RyR) agonist, caffeine (caf), and ionotropic agonists: N-methyl-d-aspartate (NMDA) receptor (NMDAR) agonist, NMDA and P2X7 receptor (P2X7R) agonist, 3'-O-(4-benzoyl)benzoyl adenosine 5'-triphosphate (BzATP) were measured in cultured mouse cortical astrocytes loaded with the fluorescent calcium indicator Fluo3-AM in a confocal laser scanning microscope. In mouse astrocytes cultured in standard medium (SM), treatment with caf increased [Ca2+]i, with a peak response occurring about 10 min after stimulus application. Peak responses to NMDA or BzATP were observed about <1 min and 4.5 min post stimulus, respectively. Co-treatment with NMDA or BzATP did not alter the peak response to caf in astrocytes cultured in SM, the absence of the effects being most likely due to asynchrony between the response to caf, NMDA and BzATP. Incubation of astrocytes with neuron-condition medium (NCM) for 24 h totally abolished the caf-evoked [Ca2+]i increase. In NCM-treated astrocytes, peak of [Ca2+]i rise evoked by NMDA was delayed to about 3.5 min, and that induced by BzATP occurred about three minutes earlier than in SM. The results show that neurons secrete factors that negatively modulate RyR-mediated Ca2+-induced Ca2+ release (CICR) in astrocytes and alter the time course of Ca2+ responses to ionotropic stimuli.
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17
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Marques F, Thapliyal S, Javer A, Shrestha P, Brown AEX, Glauser DA. Tissue-specific isoforms of the single C. elegans Ryanodine receptor gene unc-68 control specific functions. PLoS Genet 2020; 16:e1009102. [PMID: 33104696 PMCID: PMC7644089 DOI: 10.1371/journal.pgen.1009102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 11/05/2020] [Accepted: 09/08/2020] [Indexed: 11/18/2022] Open
Abstract
Ryanodine receptors (RyR) are essential regulators of cellular calcium homeostasis and signaling. Vertebrate genomes contain multiple RyR gene isoforms, expressed in different tissues and executing different functions. In contrast, invertebrate genomes contain a single RyR-encoding gene and it has long been proposed that different transcripts generated by alternative splicing may diversify their functions. Here, we analyze the expression and function of alternative exons in the C. elegans RyR gene unc-68. We show that specific isoform subsets are created via alternative promoters and via alternative splicing in unc-68 Divergent Region 2 (DR2), which actually corresponds to a region of high sequence variability across vertebrate isoforms. The expression of specific unc-68 alternative exons is enriched in different tissues, such as in body wall muscle, neurons and pharyngeal muscle. In order to infer the function of specific alternative promoters and alternative exons of unc-68, we selectively deleted them by CRISPR/Cas9 genome editing. We evaluated pharyngeal function, as well as locomotor function in swimming and crawling with high-content computer-assisted postural and behavioral analysis. Our data provide a comprehensive map of the pleiotropic impact of isoform-specific mutations and highlight that tissue-specific unc-68 isoforms fulfill distinct functions. As a whole, our work clarifies how the C. elegans single RyR gene unc-68 can fulfill multiple tasks through tissue-specific isoforms, and provide a solid foundation to further develop C. elegans as a model to study RyR channel functions and malfunctions.
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Affiliation(s)
- Filipe Marques
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Saurabh Thapliyal
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Avelino Javer
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Priyanka Shrestha
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - André E. X. Brown
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
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18
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Zampese E, Surmeier DJ. Calcium, Bioenergetics, and Parkinson's Disease. Cells 2020; 9:cells9092045. [PMID: 32911641 PMCID: PMC7564460 DOI: 10.3390/cells9092045] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Degeneration of substantia nigra (SN) dopaminergic (DAergic) neurons is responsible for the core motor deficits of Parkinson’s disease (PD). These neurons are autonomous pacemakers that have large cytosolic Ca2+ oscillations that have been linked to basal mitochondrial oxidant stress and turnover. This review explores the origin of Ca2+ oscillations and their role in the control of mitochondrial respiration, bioenergetics, and mitochondrial oxidant stress.
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19
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Belkacemi L, Darmani NA. Dopamine receptors in emesis: Molecular mechanisms and potential therapeutic function. Pharmacol Res 2020; 161:105124. [PMID: 32814171 DOI: 10.1016/j.phrs.2020.105124] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/20/2020] [Accepted: 08/05/2020] [Indexed: 12/19/2022]
Abstract
Dopamine is a member of the catecholamine family and is associated with multiple physiological functions. Together with its five receptor subtypes, dopamine is closely linked to neurological disorders such as schizophrenia, Parkinson's disease, depression, attention deficit-hyperactivity, and restless leg syndrome. Unfortunately, several dopamine receptor-based agonists used to treat some of these diseases cause nausea and vomiting as impending side-effects. The high degree of cross interactions of dopamine receptor ligands with many other targets including G-protein coupled receptors, transporters, enzymes, and ion-channels, add to the complexity of discovering new targets for the treatment of nausea and vomiting. Using activation status of signaling cascades as mechanism-based biomarkers to foresee drug sensitivity combined with the development of dopamine receptor-based biased agonists may hold great promise and seems as the next step in drug development for the treatment of such multifactorial diseases. In this review, we update the present knowledge on dopamine and dopamine receptors and their potential roles in nausea and vomiting. The pre- and clinical evidence provided in this review supports the implication of both dopamine and dopamine receptor agonists in the incidence of emesis. Besides the conventional dopaminergic antiemetic drugs, potential novel antiemetic targeting emetic protein signaling cascades may offer superior selectivity profile and potency.
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Affiliation(s)
- Louiza Belkacemi
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, 91766, USA
| | - Nissar A Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, 91766, USA.
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20
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Direct monitoring of ER Ca 2+ dynamics reveals that Ca 2+ entry induces ER-Ca 2+ release in astrocytes. Pflugers Arch 2020; 472:439-448. [PMID: 32246199 DOI: 10.1007/s00424-020-02364-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/29/2020] [Accepted: 03/12/2020] [Indexed: 12/23/2022]
Abstract
Excitability in astroglia is controlled by Ca2+ fluxes from intracellular organelles, mostly from the endoplasmic reticulum (ER). Astrocytic ER possesses inositol 1,4,5-trisphosphate receptors (InsP3R) that can be activated upon stimulation through a vast number of metabotropic G-protein-coupled receptors. By contrast, the role of Ca2+-gated Ca2+ release channels is less explored in astroglia. Here we address this process by monitoring Ca2+ dynamics directly in the cytosol and the ER of astroglial cells. Cultured astrocytes exhibited spontaneous and high-K-evoked cytosolic Ca2+ transients, both of them reversibly abolished by external Ca2+ removal, addition of plasma membrane channel blockers or ER Ca2+ depletion with SERCA inhibitors. Resting astrocyte [Ca2+]ER averaged 400 μM and maximal stimulation with ATP provoked a complete and reversible ER discharge. Direct monitoring of Ca2+ in the lumen of ER showed that high-K induced a Ca2+ release from the ER, and its amplitude was proportional to the [K]. Furthermore, by combining the low affinity GAP3 indicator targeted to the ER with the high affinity cytosolic Rhod-2, we simultaneously imaged ER- and cytosolic-Ca2+ signals, in astrocytes in culture and in situ. Plasma membrane Ca2+ entry triggered a fast ER Ca2+ release coordinated with an increase in cytosolic Ca2+. Thus, we identify a Ca2+-induced Ca2+-release (CICR) mechanism that is likely to participate in spontaneous astroglial oscillations, providing a graded amplification of the cytosolic Ca2+ signal.
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Glovaci I, Chapman CA. Dopamine induces release of calcium from internal stores in layer II lateral entorhinal cortex fan cells. Cell Calcium 2019; 80:103-111. [PMID: 30999216 DOI: 10.1016/j.ceca.2019.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 04/03/2019] [Accepted: 04/08/2019] [Indexed: 11/16/2022]
Abstract
The entorhinal cortex plays an important role in temporal lobe processes including learning and memory, object recognition, and contextual information processing. The alteration of the strength of synaptic inputs to the lateral entorhinal cortex may therefore contribute substantially to sensory and mnemonic functions. The neuromodulatory transmitter dopamine exerts powerful effects on excitatory glutamatergic synaptic transmission in the entorhinal cortex. Interestingly, inputs from midbrain dopamine neurons appear to specifically target clusters of excitatory cells located in the superficial layers of the entorhinal cortex. We have previously demonstrated that dopamine facilitates synaptic transmission through the activation of D1-like receptors. This facilitation of synaptic transmission is dependent on both activation of classical D1-like-receptors, and upon activation of dopamine receptors linked to increases in phospholipase C, inositol triphosphate (IP3), and intracellular calcium. In the present study we combined electrophysiological recordings of evoked excitatory postsynaptic currents with imaging of intracellular calcium using the fluorescent indicator fluo-4 to monitor calcium transients evoked by dopamine in electrophysiologically identified putative fan and pyramidal cells of the lateral entorhinal cortex. Bath application of dopamine (1 μM), or the phosphatidylinositol (PI)-linked D1-like-receptor agonist SKF83959 (5 μM), induced reliable and reversible increases in fluo-4 fluorescence and excitatory postsynaptic currents in fan cells, but not in pyramidal cells. In contrast, application of the classical D1-like-receptor agonist SKF38393 (10 μM) did not result in significant increases in fluorescence. Blocking release of calcium from internal stores by loading cells with the IP3 receptor blocker heparin (1 mM) or the ryanodine receptor blocker dantrolene (20 μM) abolished both the calcium transients and the facilitation of evoked synaptic currents induced by dopamine. Dopamine also induced calcium transients in fan cells when calcium was excluded from the extracellular medium, further indicating that the calcium transients are linked to release from internal stores. These results indicate that following D1-like-receptor binding, dopamine selectively induces transient elevations in intracellular calcium via activation of IP3 and ryanodine receptors, and that these elevations are linked to the facilitation of synaptic responses in putative layer II entorhinal cortex fan cells.
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Affiliation(s)
- Iulia Glovaci
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, H4B 1R6, Canada
| | - C Andrew Chapman
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, H4B 1R6, Canada.
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22
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Chirillo MA, Waters MS, Lindsey LF, Bourne JN, Harris KM. Local resources of polyribosomes and SER promote synapse enlargement and spine clustering after long-term potentiation in adult rat hippocampus. Sci Rep 2019; 9:3861. [PMID: 30846859 PMCID: PMC6405867 DOI: 10.1038/s41598-019-40520-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 02/07/2019] [Indexed: 12/11/2022] Open
Abstract
Synapse clustering facilitates circuit integration, learning, and memory. Long-term potentiation (LTP) of mature neurons produces synapse enlargement balanced by fewer spines, raising the question of how clusters form despite this homeostatic regulation of total synaptic weight. Three-dimensional reconstruction from serial section electron microscopy (3DEM) revealed the shapes and distributions of smooth endoplasmic reticulum (SER) and polyribosomes, subcellular resources important for synapse enlargement and spine outgrowth. Compared to control stimulation, synapses were enlarged two hours after LTP on resource-rich spines containing polyribosomes (4% larger than control) or SER (15% larger). SER in spines shifted from a single tubule to complex spine apparatus after LTP. Negligible synapse enlargement (0.6%) occurred on resource-poor spines lacking SER and polyribosomes. Dendrites were divided into discrete synaptic clusters surrounded by asynaptic segments. Spine density was lowest in clusters having only resource-poor spines, especially following LTP. In contrast, resource-rich spines preserved neighboring resource-poor spines and formed larger clusters with elevated total synaptic weight following LTP. These clusters also had more shaft SER branches, which could sequester cargo locally to support synapse growth and spinogenesis. Thus, resources appear to be redistributed to synaptic clusters with LTP-related synapse enlargement while homeostatic regulation suppressed spine outgrowth in resource-poor synaptic clusters.
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Affiliation(s)
- Michael A Chirillo
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712, USA.,Fulbright U.S. Scholar Program, University of Belgrade, Studentski trg 1, Belgrade, 11000, Serbia
| | - Mikayla S Waters
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712, USA.,McGovern Medical School in Houston, 6431 Fannin St., Houston, TX, 77030, USA
| | - Laurence F Lindsey
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712, USA.,Google Seattle, Seattle, Washington, 98103, USA
| | - Jennifer N Bourne
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712, USA.,Department of Cell and Developmental Biology, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Kristen M Harris
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, Texas, 78712, USA.
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23
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Reyes-Corral M, Sørensen NM, Thrasivoulou C, Dasgupta P, Ashmore JF, Ahmed A. Differential Free Intracellular Calcium Release by Class II Antiarrhythmics in Cancer Cell Lines. J Pharmacol Exp Ther 2019; 369:152-162. [PMID: 30655298 DOI: 10.1124/jpet.118.254375] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 01/02/2019] [Indexed: 12/31/2022] Open
Abstract
Class II antiarrhythmics or β-blockers are antisympathetic nervous system agents that act by blocking β-adrenoceptors. Despite their common clinical use, little is known about the effects of β-blockers on free intracellular calcium (Ca2+ i), an important cytosolic second messenger and a key regulator of cell function. We investigated the role of four chemical analogs, commonly prescribed β-blockers (atenolol, metoprolol, propranolol, and sotalol), on Ca2+ i release and whole-cell currents in mammalian cancer cells (PC3 prostate cancer and MCF7 breast cancer cell lines). We discovered that only propranolol activated free Ca2+ i release with distinct kinetics, whereas atenolol, metoprolol, and sotalol did not. The propranolol-induced Ca2+ i release was significantly inhibited by the chelation of extracellular calcium with ethylene glycol tetraacetic acid (EGTA) and by dantrolene, an inhibitor of the endoplasmic reticulum (ER) ryanodine receptor channels, and it was completely abolished by 2-aminoethoxydiphenyl borate, an inhibitor of the ER inositol-1,4,5-trisphosphate (IP3) receptor channels. Exhaustion of ER stores with 4-chloro-m-cresol, a ryanodine receptor activator, or thapsigargin, a sarco/ER Ca2+ ATPase inhibitor, precluded the propranolol-induced Ca2+ i release. Finally, preincubation of cells with sotalol or timolol, nonselective blockers of β-adrenoceptors, also reduced the Ca2+ i release activated by propranolol. Our results show that different β-blockers have differential effects on whole-cell currents and free Ca2+ i release and that propranolol activates store-operated Ca2+ i release via a mechanism that involves calcium-induced calcium release and putative downstream transducers such as IP3 The differential action of class II antiarrhythmics on Ca2+ i release may have implications on the pharmacology of these drugs.
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Affiliation(s)
- Marta Reyes-Corral
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Naja M Sørensen
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Christopher Thrasivoulou
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Prokar Dasgupta
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Jonathan F Ashmore
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Aamir Ahmed
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
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24
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Medina-Castellanos E, Villalobos-Escobedo JM, Riquelme M, Read ND, Abreu-Goodger C, Herrera-Estrella A. Danger signals activate a putative innate immune system during regeneration in a filamentous fungus. PLoS Genet 2018; 14:e1007390. [PMID: 30500812 PMCID: PMC6291166 DOI: 10.1371/journal.pgen.1007390] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 12/12/2018] [Accepted: 10/19/2018] [Indexed: 01/24/2023] Open
Abstract
The ability to respond to injury is a biological process shared by organisms of different kingdoms that can even result in complete regeneration of a part or structure that was lost. Due to their immobility, multicellular fungi are prey to various predators and are therefore constantly exposed to mechanical damage. Nevertheless, our current knowledge of how fungi respond to injury is scarce. Here we show that activation of injury responses and hyphal regeneration in the filamentous fungus Trichoderma atroviride relies on the detection of two danger or alarm signals. As an early response to injury, we detected a transient increase in cytosolic free calcium ([Ca2+]c) that was promoted by extracellular ATP, and which is likely regulated by a mechanism of calcium-induced calcium-release. In addition, we demonstrate that the mitogen activated protein kinase Tmk1 plays a key role in hyphal regeneration. Calcium- and Tmk1-mediated signaling cascades activated major transcriptional changes early following injury, including induction of a set of regeneration associated genes related to cell signaling, stress responses, transcription regulation, ribosome biogenesis/translation, replication and DNA repair. Interestingly, we uncovered the activation of a putative fungal innate immune response, including the involvement of HET domain genes, known to participate in programmed cell death. Our work shows that fungi and animals share danger-signals, signaling cascades, and the activation of the expression of genes related to immunity after injury, which are likely the result of convergent evolution.
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Affiliation(s)
- Elizabeth Medina-Castellanos
- Laboratorio Nacional de Genómica para la Biodiversidad-Unidad de Genómica Avanzada, Cinvestav, Libramiento Norte Carretera Irapuato-León, Irapuato, Gto, Mexico
| | - José Manuel Villalobos-Escobedo
- Laboratorio Nacional de Genómica para la Biodiversidad-Unidad de Genómica Avanzada, Cinvestav, Libramiento Norte Carretera Irapuato-León, Irapuato, Gto, Mexico
| | - Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana No. 3918, Ensenada, Baja California, Mexico
| | - Nick D. Read
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, United Kingdom
| | - Cei Abreu-Goodger
- Laboratorio Nacional de Genómica para la Biodiversidad-Unidad de Genómica Avanzada, Cinvestav, Libramiento Norte Carretera Irapuato-León, Irapuato, Gto, Mexico
| | - Alfredo Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad-Unidad de Genómica Avanzada, Cinvestav, Libramiento Norte Carretera Irapuato-León, Irapuato, Gto, Mexico
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25
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Yang JS, Symington S, Clark JM, Park Y. Permethrin, a pyrethroid insecticide, regulates ERK1/2 activation through membrane depolarization-mediated pathway in HepG2 hepatocytes. Food Chem Toxicol 2018; 121:387-395. [PMID: 30205134 PMCID: PMC6235143 DOI: 10.1016/j.fct.2018.09.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/16/2018] [Accepted: 09/06/2018] [Indexed: 12/29/2022]
Abstract
Permethrin is a pyrethroid insecticide that acts thru membrane depolarization and is known to disrupt calcium levels in neurons. Disrupted calcium homeostasis is linked to oxidative stress as well as many other cellular mis-functions and permethrin has been reported to disrupt lipid and glucose metabolism in animals and mammalian cell models. It is not known, however, if permethrin influences calcium levels and its associated cellular mechanisms in liver cells. Thus, the goal of the current study was to investigate the mechanisms of permethrin on calcium-mediated cellular signaling pathway, particularly on activation of extracellular signal-related kinase (ERK1/2 or p42/p44) using human hepatocytes, HepG2. The current results showed that permethrin treatment induced oxidative stress and phosphorylation of ERK1/2, which were dependent upon voltage-sensitive sodium channels (VSSC). It was further determined that permethrin-induced ERK1/2 activation was mediated by the metabotropic glutamate receptors (mGluRs)-phosphoinositide phospholipase C (PLC)-protein kinase C (PKC) pathway, but not by changes of intracellular calcium or ER stress-mediated mechanisms.
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Affiliation(s)
- Jason S Yang
- Department of Food Science, University of Massachusetts, Amherst, MA, USA
| | - Steven Symington
- Department of Biology and Biomedical Sciences, Salve Regina University, Newport, RI, USA
| | - John M Clark
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Yeonhwa Park
- Department of Food Science, University of Massachusetts, Amherst, MA, USA.
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26
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SICT: automated detection and supervised inspection of fast Ca 2+ transients. Sci Rep 2018; 8:15523. [PMID: 30341397 PMCID: PMC6195629 DOI: 10.1038/s41598-018-33847-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/05/2018] [Indexed: 02/06/2023] Open
Abstract
Recent advances in live Ca2+ imaging with increasing spatial and temporal resolution offer unprecedented opportunities, but also generate an unmet need for data processing. Here we developed SICT, a MATLAB program that automatically identifies rapid Ca2+ rises in time-lapse movies with low signal-to-noise ratios, using fluorescent indicators. A graphical user interface allows visual inspection of automatically detected events, reducing manual labour to less than 10% while maintaining quality control. The detection performance was tested using synthetic data with various signal-to-noise ratios. The event inspection phase was evaluated by four human observers. Reliability of the method was demonstrated in a direct comparison between manual and SICT-aided analysis. As a test case in cultured neurons, SICT detected an increase in frequency and duration of spontaneous Ca2+ transients in the presence of caffeine. This new method speeds up the analysis of elementary Ca2+ transients.
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27
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Dual action of L-Lactate on the activity of NR2B-containing NMDA receptors: from potentiation to neuroprotection. Sci Rep 2018; 8:13472. [PMID: 30194439 PMCID: PMC6128851 DOI: 10.1038/s41598-018-31534-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 08/21/2018] [Indexed: 12/16/2022] Open
Abstract
L-Lactate is a positive modulator of NMDAR-mediated signaling resulting in plasticity gene induction and memory consolidation. However, L-Lactate is also able to protect neurons against excito-toxic NMDAR activity, an indication of a mitigating action of L-Lactate on NMDA signaling. In this study, we provide experimental evidence that resolves this apparent paradox. Transient co-application of glutamate/glycine (1 μM/100 μM; 2 min) in primary cultures of mouse cortical neurons triggers a NMDA-dependent Ca2+ signal positively modulated by L-Lactate (10 mM) or DTT (1 mM) but decreased by Pyruvate (10 mM). This L-Lactate and DTT-induced potentiation is blocked by Ifenprodil (2 μM), a specific blocker of NMDARs containing NR2B sub-units. In contrast, co-application of glutamate/glycine (1 mM/100 μM; 2 min) elicits a NMDAR-dependent excitotoxic death in 49% of neurons. L-Lactate and Pyruvate significantly reduce this rate of cell death processes (respectively to 23% and 9%) while DTT has no effect (54% of neuronal death). This L-Lactate-induced neuroprotection is blocked by carbenoxolone and glibenclamide, respectively blockers of pannexins and KATP. In conclusion, our results show that L-Lactate is involved in two distinct and independent pathways defined as NMDAR-mediated potentiation pathway (or NADH pathway) and a neuroprotective pathway (or Pyruvate/ATP pathway), the prevalence of each one depending on the strength of the glutamatergic stimulus.
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28
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Huang X, Borgström B, Stegmayr J, Abassi Y, Kruszyk M, Leffler H, Persson L, Albinsson S, Massoumi R, Scheblykin IG, Hegardt C, Oredsson S, Strand D. The Molecular Basis for Inhibition of Stemlike Cancer Cells by Salinomycin. ACS CENTRAL SCIENCE 2018; 4:760-767. [PMID: 29974072 PMCID: PMC6026786 DOI: 10.1021/acscentsci.8b00257] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Indexed: 05/13/2023]
Abstract
Tumors are phenotypically heterogeneous and include subpopulations of cancer cells with stemlike properties. The natural product salinomycin, a K+-selective ionophore, was recently found to exert selectivity against such cancer stem cells. This selective effect is thought to be due to inhibition of the Wnt signaling pathway, but the mechanistic basis remains unclear. Here, we develop a functionally competent fluorescent conjugate of salinomycin to investigate the molecular mechanism of this compound. By subcellular imaging, we demonstrate a rapid cellular uptake of the conjugate and accumulation in the endoplasmic reticulum (ER). This localization is connected to induction of Ca2+ release from the ER into the cytosol. Depletion of Ca2+ from the ER induces the unfolded protein response as shown by global mRNA analysis and Western blot analysis of proteins in the pathway. In particular, salinomycin-induced ER Ca2+ depletion up-regulates C/EBP homologous protein (CHOP), which inhibits Wnt signaling by down-regulating β-catenin. The increased cytosolic Ca2+ also activates protein kinase C, which has been shown to inhibit Wnt signaling. These results reveal that salinomycin acts in the ER membrane of breast cancer cells to cause enhanced Ca2+ release into the cytosol, presumably by mediating a counter-flux of K+ ions. The clarified mechanistic picture highlights the importance of ion fluxes in the ER as an entry to inducing phenotypic effects and should facilitate rational development of cancer treatments.
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Affiliation(s)
- Xiaoli Huang
- Department of Biology, Lund University, Sölvegatan 35C, 223 62 Lund, Sweden
| | - Björn Borgström
- Centre for Analysis and Synthesis, Lund University, Box 124, 221 00 Lund, Sweden
| | - John Stegmayr
- Department of Biology, Lund University, Sölvegatan 35C, 223 62 Lund, Sweden
- Department of Laboratory Medicine, Lund University, BMC C12, 221 84 Lund, Sweden
| | - Yasmin Abassi
- Department of Laboratory Medicine, Translational Cancer Research, Lund University, Scheelevägen 8, 223 63 Lund, Sweden
| | - Monika Kruszyk
- Centre for Analysis and Synthesis, Lund University, Box 124, 221 00 Lund, Sweden
| | - Hakon Leffler
- Department of Laboratory Medicine, Lund University, BMC C12, 221 84 Lund, Sweden
| | - Lo Persson
- Department of Experimental Medical Science, Lund University, BMC D12, 221 84 Lund, Sweden
| | - Sebastian Albinsson
- Department of Experimental Medical Science, Lund University, BMC D12, 221 84 Lund, Sweden
| | - Ramin Massoumi
- Department of Laboratory Medicine, Translational Cancer Research, Lund University, Scheelevägen 8, 223 63 Lund, Sweden
| | - Ivan G Scheblykin
- Department of Chemical Physics and NanoLund, Lund University, Box 118, 221 00 Lund, Sweden
| | - Cecilia Hegardt
- Department of Clinical Sciences Lund, Division of Oncology and Pathology, Lund University, Medicon Village, 223 81 Lund, Sweden
| | - Stina Oredsson
- Department of Biology, Lund University, Sölvegatan 35C, 223 62 Lund, Sweden
| | - Daniel Strand
- Centre for Analysis and Synthesis, Lund University, Box 124, 221 00 Lund, Sweden
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29
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Maneshi MM, Sachs F, Hua SZ. Heterogeneous Cytoskeletal Force Distribution Delineates the Onset Ca 2+ Influx Under Fluid Shear Stress in Astrocytes. Front Cell Neurosci 2018; 12:69. [PMID: 29615869 PMCID: PMC5864927 DOI: 10.3389/fncel.2018.00069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/27/2018] [Indexed: 01/13/2023] Open
Abstract
Mechanical perturbations increase intracellular Ca2+ in cells, but the coupling of mechanical forces to the Ca2+ influx is not well understood. We used a microfluidic chamber driven with a high-speed pressure servo to generate defined fluid shear stress to cultured astrocytes, and simultaneously measured cytoskeletal forces using a force sensitive actinin optical sensor and intracellular Ca2+. Fluid shear generated non-uniform forces in actinin that critically depended on the stimulus rise time emphasizing the presence of viscoelasticity in the activating sequence. A short (ms) shear pulse with fast rise time (2 ms) produced an immediate increase in actinin tension at the upstream end of the cell with minimal changes at the downstream end. The onset of Ca2+ rise began at highly strained areas. In contrast to stimulus steps, slow ramp stimuli produced uniform forces throughout the cells and only a small Ca2+ response. The heterogeneity of force distribution is exaggerated in cells having fewer stress fibers and lower pre-tension in actinin. Disruption of cytoskeleton with cytochalasin-D (Cyt-D) eliminated force gradients, and in those cells Ca2+ elevation started from the soma. Thus, Ca2+ influx with a mechanical stimulus depends on local stress within the cell and that is time dependent due to viscoelastic mechanics.
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Affiliation(s)
- Mohammad M Maneshi
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, NY, United States.,Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY, United States
| | - Frederick Sachs
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, NY, United States
| | - Susan Z Hua
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, NY, United States.,Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY, United States
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30
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Plattner H, Verkhratsky A. Inseparable tandem: evolution chooses ATP and Ca2+ to control life, death and cellular signalling. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0419. [PMID: 27377729 DOI: 10.1098/rstb.2015.0419] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2016] [Indexed: 01/01/2023] Open
Abstract
From the very dawn of biological evolution, ATP was selected as a multipurpose energy-storing molecule. Metabolism of ATP required intracellular free Ca(2+) to be set at exceedingly low concentrations, which in turn provided the background for the role of Ca(2+) as a universal signalling molecule. The early-eukaryote life forms also evolved functional compartmentalization and vesicle trafficking, which used Ca(2+) as a universal signalling ion; similarly, Ca(2+) is needed for regulation of ciliary and flagellar beat, amoeboid movement, intracellular transport, as well as of numerous metabolic processes. Thus, during evolution, exploitation of atmospheric oxygen and increasingly efficient ATP production via oxidative phosphorylation by bacterial endosymbionts were a first step for the emergence of complex eukaryotic cells. Simultaneously, Ca(2+) started to be exploited for short-range signalling, despite restrictions by the preset phosphate-based energy metabolism, when both phosphates and Ca(2+) interfere with each other because of the low solubility of calcium phosphates. The need to keep cytosolic Ca(2+) low forced cells to restrict Ca(2+) signals in space and time and to develop energetically favourable Ca(2+) signalling and Ca(2+) microdomains. These steps in tandem dominated further evolution. The ATP molecule (often released by Ca(2+)-regulated exocytosis) rapidly grew to be the universal chemical messenger for intercellular communication; ATP effects are mediated by an extended family of purinoceptors often linked to Ca(2+) signalling. Similar to atmospheric oxygen, Ca(2+) must have been reverted from a deleterious agent to a most useful (intra- and extracellular) signalling molecule. Invention of intracellular trafficking further increased the role for Ca(2+) homeostasis that became critical for regulation of cell survival and cell death. Several mutually interdependent effects of Ca(2+) and ATP have been exploited in evolution, thus turning an originally unholy alliance into a fascinating success story.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Alexei Verkhratsky
- Faculty of Biological Sciences, University of Manchester, Manchester M13 9PT, UK Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia
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SK Channels Regulate Resting Properties and Signaling Reliability of a Developing Fast-Spiking Neuron. J Neurosci 2017; 37:10738-10747. [PMID: 28982705 DOI: 10.1523/jneurosci.1243-17.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 09/07/2017] [Accepted: 09/27/2017] [Indexed: 11/21/2022] Open
Abstract
Reliable and precise signal transmission is essential in circuits of the auditory brainstem to encode timing with submillisecond accuracy. Globular bushy cells reliably and faithfully transfer spike signals to the principal neurons of the medial nucleus of the trapezoid body (MNTB) through the giant glutamatergic synapse, the calyx of Held. Thus, the MNTB works as a relay nucleus that preserves the temporal pattern of firing at high frequency. Using whole-cell patch-clamp recordings, we observed a K+ conductance mediated by small-conductance calcium-activated potassium (SK) channels in the MNTB neurons from rats of either sex. SK channels were activated by intracellular Ca2+ sparks and mediated spontaneous transient outward currents in developing MNTB neurons. SK channels were also activated by Ca2+ influx through voltage-gated Ca2+ channels and synaptically activated NMDA receptors. Blocking SK channels with apamin depolarized the resting membrane potential, reduced resting conductance, and affected the responsiveness of MNTB neurons to signal inputs. Moreover, SK channels were activated by action potentials and affected the spike afterhyperpolarization. Blocking SK channels disrupted the one-to-one signal transmission from presynaptic calyces to postsynaptic MNTB neurons and induced extra postsynaptic action potentials in response to presynaptic firing. These data reveal that SK channels play crucial roles in regulating the resting properties and maintaining reliable signal transmission of MNTB neurons.SIGNIFICANCE STATEMENT Reliable and precise signal transmission is required in auditory brainstem circuits to localize the sound source. The calyx of Held synapse in the mammalian medial nucleus of the trapezoid body (MNTB) plays an important role in sound localization. We investigated the potassium channels that shape the reliability of signal transfer across the calyceal synapse and observed a potassium conductance mediated by small-conductance calcium-activated potassium (SK) channels in rat MNTB principal neurons. We found that SK channels are tonically activated and contribute to the resting membrane properties of MNTB neurons. Interestingly, SK channels are transiently activated by calcium sparks and calcium influx during action potentials and control the one-to-one signal transmission from presynaptic calyces to postsynaptic MNTB neurons.
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Wakita M, Shoudai K, Oyama Y, Akaike N. 4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) modifies synaptic transmission in hippocampal CA3 neurons of rats. CHEMOSPHERE 2017; 184:337-346. [PMID: 28605704 DOI: 10.1016/j.chemosphere.2017.05.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 05/23/2017] [Accepted: 05/28/2017] [Indexed: 06/07/2023]
Abstract
4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) is an alternative to organotin antifoulants, such as tributyltin and triphenyltin. Since DCOIT is found in harbors, bays, and coastal areas worldwide, this chemical compound may have some impacts on ecosystems. To determine whether DCOIT possesses neurotoxic activity by modifying synaptic transmission, we examined the effects of DCOIT on synaptic transmission in a 'synaptic bouton' preparation of rat brain. DCOIT at concentrations of 0.03-1 μM increased the amplitudes of evoked synaptic currents mediated by GABA and glutamate, while it reduced the amplitudes of these currents at 3-10 μM. However, the currents elicited by exogenous applications of GABA and glutamate were not affected by DCOIT. DCOIT at 1-10 μM increased the frequency of spontaneous synaptic currents mediated by GABA. It also increased the frequency of glutamate-mediated spontaneous currents at0.3-10 μM. The frequencies of miniature synaptic currents mediated by GABA and glutamate, observed in the presence of tetrodotoxin under external Ca2+-free conditions, were increased by 10 μM DCOIT. With the repetitive applications of DCOIT, the frequency of miniature synaptic currents mediated by glutamate was not increased by the second and third applications of DCOIT. Voltage-dependent Ca2+ channels were not affected by DCOIT, but DCOIT slowed the inactivation of voltage-dependent Na+ channels. These results suggest that DCOIT increases Ca2+ release from intracellular Ca2+ stores, resulting in the facilitation of both action potential-dependent and spontaneous neurotransmission, possibly leading to neurotoxicity.
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Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto, 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, Kumamoto, 861-5598, Japan.
| | - Kiyomitsu Shoudai
- Research Division for Life Science, Kumamoto Health Science University, Kumamoto, 861-5598, Japan
| | - Yasuo Oyama
- Laboratory of Cellular Signaling, Faculty of Biosciences and Bioindustry, Tokushima University, Tokushima, 770-8513, Japan.
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto, 860-8518, Japan; Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
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Roncacè V, Polli FS, Zojicic M, Kohlmeier KA. Neuropeptide S (NPS) is a neuropeptide with cellular actions in arousal and anxiety-related nuclei: Functional implications for effects of NPS on wakefulness and mood. Neuropharmacology 2017; 126:292-317. [PMID: 28655610 DOI: 10.1016/j.neuropharm.2017.06.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/02/2017] [Accepted: 06/23/2017] [Indexed: 12/27/2022]
Abstract
Neuropeptide S (NPS) is a peptide recently recognized to be present in the CNS, and believed to play a role in vigilance and mood control, as behavioral studies have shown it promotes arousal and has an anxiolytic effect. Although NPS precursor is found in very few neurons, NPS positive fibers are present throughout the brain stem. Given the behavioral actions of this peptide and the wide innervation pattern, we examined the cellular effects of NPS within two brain stem nuclei known to play a critical role in anxiety and arousal: the dorsal raphe (DR) and laterodorsal tegmentum (LDT). In mouse brain slices, NPS increased cytoplasmic levels of calcium in DR and LDT cells. Calcium rises were independent of action potential generation, reduced by low extracellular levels of calcium, attenuated by IP3 - and ryanodine (RyR)-dependent intracellular calcium store depletion, and eliminated by the receptor (NPSR) selective antagonist, SHA 68. NPS also exerted an effect on the membrane of DR and LDT cells inducing inward and outward currents, which were driven by an increase in conductance, and eliminated by SHA 68. Membrane actions of NPS were found to be dependent on store-mediated calcium as depletion of IP3 and RyR stores eliminated NPS-induced currents. Finally, NPS also had actions on synaptic events, suggesting facilitation of glutamatergic and GABAergic presynaptic transmission. When taken together, actions of NPS influenced the excitability of DR and LDT neurons, which could play a role in the anxiolytic and arousal-promoting effects of this peptide.
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Affiliation(s)
- Vincenzo Roncacè
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen Ø, Denmark
| | - Filip Souza Polli
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen Ø, Denmark
| | - Minella Zojicic
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen Ø, Denmark
| | - Kristi A Kohlmeier
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen Ø, Denmark.
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Reddish FN, Miller CL, Gorkhali R, Yang JJ. Calcium Dynamics Mediated by the Endoplasmic/Sarcoplasmic Reticulum and Related Diseases. Int J Mol Sci 2017; 18:E1024. [PMID: 28489021 PMCID: PMC5454937 DOI: 10.3390/ijms18051024] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 04/28/2017] [Accepted: 05/01/2017] [Indexed: 12/17/2022] Open
Abstract
The flow of intracellular calcium (Ca2+) is critical for the activation and regulation of important biological events that are required in living organisms. As the major Ca2+ repositories inside the cell, the endoplasmic reticulum (ER) and the sarcoplasmic reticulum (SR) of muscle cells are central in maintaining and amplifying the intracellular Ca2+ signal. The morphology of these organelles, along with the distribution of key calcium-binding proteins (CaBPs), regulatory proteins, pumps, and receptors fundamentally impact the local and global differences in Ca2+ release kinetics. In this review, we will discuss the structural and morphological differences between the ER and SR and how they influence localized Ca2+ release, related diseases, and the need for targeted genetically encoded calcium indicators (GECIs) to study these events.
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Affiliation(s)
- Florence N Reddish
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
| | - Cassandra L Miller
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
| | - Rakshya Gorkhali
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
| | - Jenny J Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, GA 30303, USA.
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Tolstykh GP, Olsovsky CA, Ibey BL, Beier HT. Ryanodine and IP 3 receptor-mediated calcium signaling play a pivotal role in neurological infrared laser modulation. NEUROPHOTONICS 2017; 4:025001. [PMID: 28413806 PMCID: PMC5381754 DOI: 10.1117/1.nph.4.2.025001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/20/2017] [Indexed: 05/13/2023]
Abstract
Pulsed infrared (IR) laser energy has been shown to modulate neurological activity through both stimulation and inhibition of action potentials. While the mechanism(s) behind this phenomenon is (are) not completely understood, certain hypotheses suggest that the rise in temperature from IR exposure could activate temperature- or pressure-sensitive ion channels or create pores in the cellular outer membrane, allowing an influx of typically plasma-membrane-impermeant ions. Studies using fluorescent intensity-based calcium ion ([Formula: see text]) sensitive dyes show changes in [Formula: see text] levels after various IR stimulation parameters, which suggests that [Formula: see text] may originate from the external solution. However, activation of intracellular signaling pathways has also been demonstrated, indicating a more complex mechanism of increasing intracellular [Formula: see text] concentration. We quantified the [Formula: see text] mobilization in terms of influx from the external solution and efflux from intracellular organelles using Fura-2 and a high-speed ratiometric imaging system that rapidly alternates the dye excitation wavelengths. Using nonexcitable Chinese hamster ovarian ([Formula: see text]) cells and neuroblastoma-glioma (NG108) cells, we demonstrate that intracellular [Formula: see text] receptors play an important role in the IR-induced [Formula: see text], with the [Formula: see text] response augmented by ryanodine receptors in excitable cells.
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Affiliation(s)
- Gleb P. Tolstykh
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, United States
- Address all correspondence to: Gleb P. Tolstykh, E-mail:
| | - Cory A. Olsovsky
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
| | - Bennett L. Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, Texas, United States
| | - Hope T. Beier
- Air Force Research Laboratory, 711th Human Performance Wing, Airman System Directorate, Bioeffects Division, Optical Radiation Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, Texas, United States
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36
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Diacylglycerol kinase ε localizes to subsurface cisterns of cerebellar Purkinje cells. Cell Tissue Res 2017; 368:441-458. [PMID: 28191598 DOI: 10.1007/s00441-017-2579-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 01/16/2017] [Indexed: 10/20/2022]
Abstract
Following activation of Gq protein-coupled receptors, phospholipase C yields a pair of second messengers: diacylglycerol (DG) and inositol 1,4,5-trisphosphate. Diacylglycerol kinase (DGK) phosphorylates DG to produce phosphatidic acid, another second messenger. Of the DGK family, DGKε is the only DGK isoform that exhibits substrate specificity for DG with an arachidonoyl acyl chain at the sn-2 position. Recently, we demonstrated that hydrophobic residues in the N-terminus of DGKε play an important role in targeting the endoplasmic reticulum in transfected cells. However, its cellular expression and subcellular localization in the brain remain elusive. In the present study, we investigate this issue using specific DGKε antibody. DGKε was richly expressed in principal neurons of higher brain regions, including pyramidal cells in the hippocampus and neocortex, medium spiny neurons in the striatum and Purkinje cells in the cerebellum. In Purkinje cells, DGKε was localized to the subsurface cisterns and colocalized with inositol 1,4,5-trisphosphate receptor-1 in dendrites and axons. In dendrites of Purkinje cells, DGKε was also distributed in close apposition to DG lipase-α, which catalyzes arachidonoyl-DG to produce 2-arachidonoyl glycerol, a major endocannabinoid in the brain. Behaviorally, DGKε-knockout mice exhibited hyper-locomotive activities and impaired motor coordination and learning. These findings suggest that DGKε plays an important role in neuronal and brain functions through its distinct neuronal expression and subcellular localization and also through coordinated arrangement with other molecules involving the phosphoinositide signaling pathway.
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37
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Petrou T, Olsen HL, Thrasivoulou C, Masters JR, Ashmore JF, Ahmed A. Intracellular Calcium Mobilization in Response to Ion Channel Regulators via a Calcium-Induced Calcium Release Mechanism. J Pharmacol Exp Ther 2016; 360:378-387. [PMID: 27980039 PMCID: PMC5267512 DOI: 10.1124/jpet.116.236695] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 11/14/2016] [Indexed: 01/19/2023] Open
Abstract
Free intracellular calcium ([Ca2+]i), in addition to being an important second messenger, is a key regulator of many cellular processes including cell membrane potential, proliferation, and apoptosis. In many cases, the mobilization of [Ca2+]i is controlled by intracellular store activation and calcium influx. We have investigated the effect of several ion channel modulators, which have been used to treat a range of human diseases, on [Ca2+]i release, by ratiometric calcium imaging. We show that six such modulators [amiodarone (Ami), dofetilide, furosemide (Fur), minoxidil (Min), loxapine (Lox), and Nicorandil] initiate release of [Ca2+]i in prostate and breast cancer cell lines, PC3 and MCF7, respectively. Whole-cell currents in PC3 cells were inhibited by the compounds tested in patch-clamp experiments in a concentration-dependent manner. In all cases [Ca2+]i was increased by modulator concentrations comparable to those used clinically. The increase in [Ca2+]i in response to Ami, Fur, Lox, and Min was reduced significantly (P < 0.01) when the external calcium was reduced to nM concentration by chelation with EGTA. The data suggest that many ion channel regulators mobilize [Ca2+]i. We suggest a mechanism whereby calcium-induced calcium release is implicated; such a mechanism may be important for understanding the action of these compounds.
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Affiliation(s)
- Terry Petrou
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Hervør L Olsen
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Christopher Thrasivoulou
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - John R Masters
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Jonathan F Ashmore
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Aamir Ahmed
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
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38
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Milograna SR, Ribeiro MR, Bell FT, McNamara JC. Pigment Translocation in Caridean Shrimp Chromatophores: Receptor Type, Signal Transduction, Second Messengers, and Cross Talk Among Multiple Signaling Cascades. ACTA ACUST UNITED AC 2016; 325:565-580. [PMID: 27935256 DOI: 10.1002/jez.2052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 10/17/2016] [Accepted: 10/30/2016] [Indexed: 11/07/2022]
Abstract
Pigment aggregation in shrimp chromatophores is triggered by red pigment concentrating hormone (RPCH), a neurosecretory peptide whose plasma membrane receptor may be a G-protein coupled receptor (GPCR). While RPCH binding activates the Ca2+ /cGMP signaling cascades, a role for cyclic AMP (cAMP) in pigment aggregation is obscure, as are the steps governing Ca2+ release from the smooth endoplasmic reticulum (SER). A role for the antagonistic neuropeptide, pigment dispersing homone (α-PDH) is also unclear. In red, ovarian chromatophores from the freshwater shrimp Macrobrachium olfersi, we show that a G-protein antagonist (AntPG) strongly inhibits RPCH-triggered pigment aggregation, suggesting that RPCH binds to a GPCR, activating an inhibitory G-protein. Decreasing cAMP levels may cue pigment aggregation, since cytosolic cAMP titers, when augmented by cholera toxin, forskolin or vinpocentine, completely or partially impair pigment aggregation. Triggering opposing Ca2+ /cGMP and cAMP cascades by simultaneous perfusion with lipid-soluble cyclic nucleotide analogs induces a "tug-of-war" response, pigments aggregating in some chromatosomes with unpredictable, oscillatory movements in others. Inhibition of cAMP-dependent protein kinase accelerates aggregation and reduces dispersion velocities, suggesting a role in phosphorylation events, possibly regulating SER Ca2+ release and pigment aggregation. The second messengers IP3 and cADPR do not stimulate SER Ca2+ release. α-PDH does not sustain pigment dispersion, suggesting that pigment translocation in caridean chromatophores may be regulated solely by RPCH, since PDH is not required. We propose a working hypothesis to further unravel key steps in the mechanisms of pigment translocation within crustacean chromatophores that have remained obscure for nearly a century.
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Affiliation(s)
- Sarah Ribeiro Milograna
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Márcia Regina Ribeiro
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Fernanda Tinti Bell
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - John Campbell McNamara
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil.,Centro de Biologia Marinha, Universidade de São Paulo, São Paulo, Brazil
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39
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Korvers L, de Andrade Costa A, Mersch M, Matyash V, Kettenmann H, Semtner M. Spontaneous Ca 2+ transients in mouse microglia. Cell Calcium 2016; 60:396-406. [PMID: 27697289 DOI: 10.1016/j.ceca.2016.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 02/07/2023]
Abstract
Microglia are the resident immune cells in the central nervous system and many of their physiological functions are known to be linked to intracellular calcium (Ca2+) signaling. Here we show that isolated and purified mouse microglia-either freshly or cultured-display spontaneous and transient Ca2+ elevations lasting for around ten to twenty seconds and occurring at frequencies of around five to ten events per hour and cell. The events were absent after depletion of internal Ca2+ stores, by phospholipase C (PLC) inhibition or blockade of inositol-1,4,5-trisphosphate receptors (IP3Rs), but not by removal of extracellular Ca2+, indicating that Ca2+ is released from endoplasmic reticulum intracellular stores. We furthermore provide evidence that autocrine ATP release and subsequent activation of purinergic P2Y receptors is not the trigger for these events. Spontaneous Ca2+ transients did also occur after stimulation with Lipopolysaccharide (LPS) and in glioma-associated microglia, but their kinetics differed from control conditions. We hypothesize that spontaneous Ca2+ transients reflect aspects of cellular homeostasis that are linked to regular and patho-physiological functions of microglia.
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Affiliation(s)
- Laura Korvers
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Amanda de Andrade Costa
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Martin Mersch
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Vitali Matyash
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Helmut Kettenmann
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany
| | - Marcus Semtner
- Max-Delbrueck-Centrum for Molecular Medicine (MDC) in the Helmholtz Association, Cellular Neurosciences, Robert-Roessle-Str. 10, 13092 Berlin, Germany.
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40
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Young LM, Geldenhuys WJ, Domingo OC, Malan SF, Van der Schyf CJ. Synthesis and Biological Evaluation of Pentacycloundecylamines and Triquinylamines as Voltage-Gated Calcium Channel Blockers. Arch Pharm (Weinheim) 2016; 349:252-67. [PMID: 26892182 PMCID: PMC5482218 DOI: 10.1002/ardp.201500293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 01/27/2016] [Accepted: 01/27/2016] [Indexed: 01/21/2023]
Abstract
Preclinical studies for neurodegenerative diseases have shown a multi-targeted approach to be successful in the treatment of these complex disorders with several pathoetiological pathways. Polycyclic compounds, such as NGP1-01 (7a), have demonstrated the ability to target multiple mechanisms of the complex etiology and are referred to as multifunctional compounds. These compounds have served as scaffolds with the ability to attenuate Ca(2+) overload and excitotoxicity through several pathways. In this study, our focus was on mitigating Ca(2+) overload through the L-type calcium channels (LTCC). Here, we report the synthesis and biological evaluation of several novel polycyclic compounds. We determined the IC50 values for both the pentacycloundecylamines and the triquinylamines by means of a high-throughput fluorescence calcium flux assay utilizing Fura-2/AM. The potential of these compounds to offer protection against hydrogen peroxide-induced cell death was also evaluated. Overall, 8-benzylamino-8,11-oxapentacyclo[5.4.0.0(2,6) .0(3,10) .0(5,9) ]undecane (NGP1-01, 7a) had the most favorable pharmacological profile with an IC50 value of 86 µM for LTCC inhibition and significant reduction of hydrogen peroxide-induced cell death. In general, the triquinylamines were more active as LTCC blockers than the oxa-pentacycloundecylamines. The aza-pentacycloundecylamines were potent LTCC inhibitors, with 8-hydroxy-N-phenylethyl-8,11-azapentacyclo[5.4.0.0(2,6) .0(3,10) .0(5,9) ]undecane (8b) also able to offer significant protection in the cell viability assays.
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Affiliation(s)
- Lois-May Young
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
- Pharmaceutical Chemistry, School of Pharmacy, North-West University, Potchefstroom, South Africa
| | - Werner J. Geldenhuys
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Olwen C. Domingo
- Pharmaceutical Chemistry, School of Pharmacy, North-West University, Potchefstroom, South Africa
| | - Sarel F. Malan
- Pharmaceutical Chemistry, School of Pharmacy, North-West University, Potchefstroom, South Africa
- School of Pharmacy, University of the Western Cape, Bellville, South Africa
| | - Cornelis J. Van der Schyf
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Pocatello, ID, USA
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41
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Neyer C, Herr D, Kohmann D, Budde T, Pape HC, Coulon P. mGluR-mediated calcium signalling in the thalamic reticular nucleus. Cell Calcium 2016; 59:312-23. [PMID: 27041217 DOI: 10.1016/j.ceca.2016.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 10/22/2022]
Abstract
The thalamic reticular nucleus (TRN) plays a major role in modulating the transfer of information from the thalamus to the cortex. GABAergic inhibition via the TRN is differentially regulated by metabotropic glutamate receptors (mGluRs) and the effect of mGluRs on the membrane potential, on ion channels, and on the plasticity of electrical coupling of TRN neurons has been studied previously. Although mGluRs are generally known to trigger Ca(2+) transients, mGluR-mediated Ca(2+)-transients in TRN neurons have not yet been investigated. In this study, we show that mGluRs can trigger Ca(2+)-transients in TRN neurons, that these transients depend on intracellular Ca(2+)-stores, and are mediated by IP3 receptors. Ca(2+) transients caused by the group I mGluR agonist DHPG elicit a current that is sensitive to flufenamic acid and has a reversal potential around -40mV. Our results add mGluR-mediated Ca(2+)-signalling in the TRN to the state-dependent modulators of the thalamocortical system.
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Affiliation(s)
- Christina Neyer
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - David Herr
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Denise Kohmann
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Thomas Budde
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Hans-Christian Pape
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany
| | - Philippe Coulon
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Münster, Germany; Center For Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.
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Moore BD, Jin RU, Lo H, Jung M, Wang H, Battle MA, Wollheim CB, Urano F, Mills JC. Transcriptional Regulation of X-Box-binding Protein One (XBP1) by Hepatocyte Nuclear Factor 4α (HNF4Α) Is Vital to Beta-cell Function. J Biol Chem 2016; 291:6146-57. [PMID: 26792861 DOI: 10.1074/jbc.m115.685750] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Indexed: 12/20/2022] Open
Abstract
The transcription factor, X-box-binding protein-1 (XBP1), controls the development and maintenance of the endoplasmic reticulum (ER) in multiple secretory cell lineages. We show here that Hepatocyte Nuclear Factor 4α (HNF4α) directly induces XBP1 expression. Mutations in HNF4α cause Mature-Onset Diabetes of the Young I (MODYI), a subset of diabetes characterized by diminished GSIS. In mouse models, cell lines, and ex vivo islets, using dominant negative and human- disease-allele point mutants or knock-out and knockdown models, we show that disruption of HNF4α caused decreased expression of XBP1 and reduced cellular ER networks. GSIS depends on ER Ca(2+) signaling; we show that diminished XBP1 and/or HNF4α in β-cells led to impaired ER Ca(2+) homeostasis. Restoring XBP1 expression was sufficient to completely rescue GSIS in HNF4α-deficient β-cells. Our findings uncover a transcriptional relationship between HNF4α and Xbp1 with potentially broader implications about MODYI and the importance of transcription factor signaling in the regulation of secretion.
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Affiliation(s)
- Benjamin D Moore
- From the Division of Gastroenterology, Departments of Medicine, Pathology & Immunology, and Developmental Biology, Washington University, St. Louis, Missouri 63110
| | - Ramon U Jin
- From the Division of Gastroenterology, Departments of Medicine, Pathology & Immunology, and Developmental Biology, Washington University, St. Louis, Missouri 63110
| | - Heiyong Lo
- From the Division of Gastroenterology, Departments of Medicine, Pathology & Immunology, and Developmental Biology, Washington University, St. Louis, Missouri 63110
| | - Min Jung
- From the Division of Gastroenterology, Departments of Medicine, Pathology & Immunology, and Developmental Biology, Washington University, St. Louis, Missouri 63110
| | - Haiyan Wang
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Michele A Battle
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Claes B Wollheim
- Lund University Diabetes Center, Department of Clinical Sciences, Diabetes & Endocrinology, Skåne University Hospital, Lund University, Malmö 20502, Sweden, Department of Cell Physiology and Metabolism, Université de Genève, University Medical Centre, 1 rue Michel-Servet, Geneva 4 1211, Switzerland, and
| | - Fumihiko Urano
- Division of Endocrinology, Departments of Medicine, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jason C Mills
- From the Division of Gastroenterology, Departments of Medicine, Pathology & Immunology, and Developmental Biology, Washington University, St. Louis, Missouri 63110,
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43
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Jessen SB, Mathiesen C, Lind BL, Lauritzen M. Interneuron Deficit Associates Attenuated Network Synchronization to Mismatch of Energy Supply and Demand in Aging Mouse Brains. Cereb Cortex 2015; 27:646-659. [DOI: 10.1093/cercor/bhv261] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Sanne Barsballe Jessen
- Department of Neuroscience and Pharmacology
- Center for Healthy Aging, University of Copenhagen, Copenhagen N 2200, Denmark
| | - Claus Mathiesen
- Department of Neuroscience and Pharmacology
- Center for Healthy Aging, University of Copenhagen, Copenhagen N 2200, Denmark
| | | | - Martin Lauritzen
- Department of Neuroscience and Pharmacology
- Center for Healthy Aging, University of Copenhagen, Copenhagen N 2200, Denmark
- Department of Clinical Neurophysiology, Glostrup Hospital, Glostrup 2600, Denmark
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Activation of Phosphatidylinositol-Linked Dopamine Receptors Induces a Facilitation of Glutamate-Mediated Synaptic Transmission in the Lateral Entorhinal Cortex. PLoS One 2015; 10:e0131948. [PMID: 26133167 PMCID: PMC4489908 DOI: 10.1371/journal.pone.0131948] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/08/2015] [Indexed: 11/19/2022] Open
Abstract
The lateral entorhinal cortex receives strong inputs from midbrain dopamine neurons that can modulate its sensory and mnemonic function. We have previously demonstrated that 1 µM dopamine facilitates synaptic transmission in layer II entorhinal cortex cells via activation of D1-like receptors, increased cAMP-PKA activity, and a resulting enhancement of AMPA-receptor mediated currents. The present study assessed the contribution of phosphatidylinositol (PI)-linked D1 receptors to the dopaminergic facilitation of transmission in layer II of the rat entorhinal cortex, and the involvement of phospholipase C activity and release of calcium from internal stores. Whole-cell patch-clamp recordings of glutamate-mediated evoked excitatory postsynaptic currents were obtained from pyramidal and fan cells. Activation of D1-like receptors using SKF38393, SKF83959, or 1 µM dopamine induced a reversible facilitation of EPSCs which was abolished by loading cells with either the phospholipase C inhibitor U-73122 or the Ca2+ chelator BAPTA. Neither the L-type voltage-gated Ca2+ channel blocker nifedipine, nor the L/N-type channel blocker cilnidipine, blocked the facilitation of synaptic currents. However, the facilitation was blocked by blocking Ca2+ release from internal stores via inositol 1,4,5-trisphosphate (InsP3) receptors or ryanodine receptors. Follow-up studies demonstrated that inhibiting CaMKII activity with KN-93 failed to block the facilitation, but that application of the protein kinase C inhibitor PKC(19-36) completely blocked the dopamine-induced facilitation. Overall, in addition to our previous report indicating a role for the cAMP-PKA pathway in dopamine-induced facilitation of synaptic transmission, we demonstrate here that the dopaminergic facilitation of synaptic responses in layer II entorhinal neurons also relies on a signaling cascade dependent on PI-linked D1 receptors, PLC, release of Ca2+ from internal stores, and PKC activation which is likely dependent upon both DAG and enhanced intracellular Ca2+. These signaling pathways may collaborate to enhance sensory and mnemonic function in the entorhinal cortex during tonic release of dopamine.
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45
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Maneshi MM, Sachs F, Hua SZ. A Threshold Shear Force for Calcium Influx in an Astrocyte Model of Traumatic Brain Injury. J Neurotrauma 2015; 32:1020-9. [PMID: 25442327 DOI: 10.1089/neu.2014.3677] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Traumatic brain injury (TBI) refers to brain damage resulting from external mechanical force, such as a blast or crash. Our current understanding of TBI is derived mainly from in vivo studies that show measurable biological effects on neurons sampled after TBI. Little is known about the early responses of brain cells during stimuli and which features of the stimulus are most critical to cell injury. We generated defined shear stress in a microfluidic chamber using a fast pressure servo and examined the intracellular Ca(2+) levels in cultured adult astrocytes. Shear stress increased intracellular Ca(2+) depending on the magnitude, duration, and rise time of the stimulus. Square pulses with a fast rise time (∼2 ms) caused transient increases in intracellular Ca(2+), but when the rise time was extended to 20 ms, the response was much less. The threshold for a response is a matrix of multiple parameters. Cells can integrate the effect of shear force from repeated challenges: A pulse train of 10 narrow pulses (11.5 dyn/cm(2) and 10 ms wide) resulted in a 4-fold increase in Ca(2+) relative to a single pulse of the same amplitude 100 ms wide. The Ca(2+) increase was eliminated in Ca(2+)-free media, but was observed after depleting the intracellular Ca(2+) stores with thapsigargin suggesting the need for a Ca(2+) influx. The Ca(2+) influx was inhibited by extracellular Gd(3+), a nonspecific inhibitor of mechanosensitive ion channels, but it was not affected by the more specific inhibitor, GsMTx4. The voltage-gated channel blockers, nifedipine, diltiazem, and verapamil, were also ineffective. The data show that the mechanically induced Ca(2+) influx commonly associated with neuron models for TBI is also present in astrocytes, and there is a viscoelastic/plastic coupling of shear stress to the Ca(2+) influx. The site of Ca(2+) influx has yet to be determined.
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Affiliation(s)
| | - Frederick Sachs
- 2 Department of Physiology and Biophysics, SUNY-Buffalo , Buffalo, New York
| | - Susan Z Hua
- 1 Department of Mechanical and Aerospace Engineering, SUNY-Buffalo , Buffalo, New York.,2 Department of Physiology and Biophysics, SUNY-Buffalo , Buffalo, New York
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Wakita M, Oyama Y, Takase Y, Akaike N. Modulation of excitatory synaptic transmission in rat hippocampal CA3 neurons by triphenyltin, an environmental pollutant. CHEMOSPHERE 2015; 120:598-607. [PMID: 25462303 DOI: 10.1016/j.chemosphere.2014.09.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 09/19/2014] [Accepted: 09/22/2014] [Indexed: 06/04/2023]
Abstract
Triphenyltin (TPT) is an organometallic compound that poses a known environmental hazard to some fish and mollusks, as well as mammals. However, its neurotoxic mechanisms in the mammalian brain are still unclear. Thus, we have investigated mechanisms through which TPT modulates glutamatergic synaptic transmission, including spontaneous, miniature, and evoked excitatory postsynaptic currents (sEPSCs, mEPSCs, and eEPSCs respectively), in a rat hippocampal CA3 'synaptic-bouton' preparation. TPT, at environmentally relevant concentrations (30 nM to 1 μM), significantly increased the frequency of sEPSCs and mEPSCs in a concentration-dependent manner, without affecting the currents' amplitudes. The facilitatory effects of TPT on mEPSC frequency were seen even in a Ca(2+)-free external solution containing tetrodotoxin. These effects were further prolonged by adding caffeine, which releases Ca(2+) from intracellular Ca(2+) storage sites. In glutamatergic eEPSCs evoked by paired-pulse stimuli, TPT at concentrations greater than or equal to 100 nM markedly increased the current amplitude by the first pulse and decreased failure rate and pair-pulse ratio. On the other hand, both voltage-dependent Na(+) and Ca(2+) channels were unaffected by submicromolar concentrations of TPT. Overall, these results suggest that TPT, at environmentally relevant concentrations, affects presynaptic transmitter release machinery by directly modulating Ca(2+) storage. Further, findings of this study imply that excitotoxic mechanisms may underlie TPT-induced neuronal damage.
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Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, Kumamoto 861-5598, Japan.
| | - Yasuo Oyama
- Laboratory of Cellular Signaling, Faculty of Integrated Arts and Sciences, University of Tokushima, Tokushima 770-8501, Japan.
| | - Yuko Takase
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto 860-8518, Japan
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, Kumamoto 861-5598, Japan.
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Vrecl M, Babnik M, Diacci U, Benoit E, Frangež R. Effect of the ostreolysin A/pleurotolysin B pore-forming complex on neuroblastoma cell morphology and intracellular Ca²⁺ activity. Toxicol Sci 2015; 144:276-83. [PMID: 25556216 DOI: 10.1093/toxsci/kfu316] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ostreolysin A (OlyA) and pleurotolysin B (PlyB), isolated from edible oyster mushrooms, form a cytolytic complex (OlyA/PlyB) in membrane cells that causes respiratory arrest. This study evaluated the mechanisms underlying cytotoxic OlyA/PlyB activity in neuroblastoma NG108-15 cells. Confocal microscopy with morphometric analysis revealed that OlyA/PlyB increased the 3-dimensional projected area of differentiated cells. Iso-osmotic replacement of NaCl by sucrose or Na-isethionate prevented the cellular swelling. This suggests that formation of cellular edema requires the presence of Na(+) and/or Cl(-) in the extracellular space and may be related to an influx of Na(+) and/or a shift in Cl(-), which induce a marked influx of water that is ultimately responsible for cellular swelling. In addition, extracellular Ca(2+) moderately contributed to the swelling because benzamil (10 µM), a 3Na(+)/Ca(2+) exchange (NCX) inhibitor, and Ca(2+)-free medium partially prevented this response. Fluorometric measurements revealed that OlyA/PlyB, at approximately 15-fold higher concentrations, increased the intracellular Ca(2+) activity [Ca(2+)]i. This increase was dependent on the presence of Na(+) and Ca(2+) in the external medium and was sensitive to benzamil. It is thus likely that a switch in the NCX mode, associated with the de novo formation of non-selective ion pores by OlyA/PlyB in cellular plasma membranes, plays an important role in this effect. Overall, OlyA/PlyB affects neuroblastoma cell morphology and Ca(2+) homeostasis to influence the toxin-induced respiratory arrest.
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Affiliation(s)
- Milka Vrecl
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Monika Babnik
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Uroš Diacci
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Evelyne Benoit
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Robert Frangež
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
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Kurokawa K, Mizuno K, Ohkuma S. Sensitization of ethanol-induced place preference as a result of up-regulation of type 1 inositol 1,4,5-trisphosphate receptors in mouse nucleus accumbens. J Neurochem 2014; 131:836-47. [DOI: 10.1111/jnc.12945] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 09/04/2014] [Accepted: 09/05/2014] [Indexed: 12/23/2022]
Affiliation(s)
- Kazuhiro Kurokawa
- Department of Pharmacology; Kawasaki Medical School; Kurashiki Japan
| | - Koji Mizuno
- Department of Pharmacology; Kawasaki Medical School; Kurashiki Japan
| | - Seitaro Ohkuma
- Department of Pharmacology; Kawasaki Medical School; Kurashiki Japan
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49
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Calcium signalling in sensory neurones and peripheral glia in the context of diabetic neuropathies. Cell Calcium 2014; 56:362-71. [PMID: 25149565 DOI: 10.1016/j.ceca.2014.07.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/11/2014] [Accepted: 07/12/2014] [Indexed: 12/14/2022]
Abstract
Peripheral sensory nervous system is comprised of neurones with their axons and neuroglia that includes satellite glial cells in sensory ganglia, myelinating, non-myelinating and perisynaptic Schwann cells. Pathogenesis of peripheral diabetic polyneuropathies is associated with aberrant function of both neurones and glia. Deregulated Ca(2+) homoeostasis and aberrant Ca(2+) signalling in neuronal and glial elements contributes to many forms of neuropathology and is fundamental to neurodegenerative diseases. In diabetes both neurones and glia experience metabolic stress and mitochondrial dysfunction which lead to deregulation of Ca(2+) homeostasis and Ca(2+) signalling, which in their turn lead to pathological cellular reactions contributing to development of diabetic neuropathies. Molecular cascades responsible for Ca(2+) homeostasis and signalling, therefore, can be regarded as potential therapeutic targets.
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50
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Mandikian D, Bocksteins E, Parajuli LK, Bishop HI, Cerda O, Shigemoto R, Trimmer JS. Cell type-specific spatial and functional coupling between mammalian brain Kv2.1 K+ channels and ryanodine receptors. J Comp Neurol 2014; 522:3555-74. [PMID: 24962901 DOI: 10.1002/cne.23641] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 06/17/2014] [Accepted: 06/20/2014] [Indexed: 11/08/2022]
Abstract
The Kv2.1 voltage-gated K+ channel is widely expressed throughout mammalian brain, where it contributes to dynamic activity-dependent regulation of intrinsic neuronal excitability. Here we show that somatic plasma membrane Kv2.1 clusters are juxtaposed to clusters of intracellular ryanodine receptor (RyR) Ca2+ -release channels in mouse brain neurons, most prominently in medium spiny neurons (MSNs) of the striatum. Electron microscopy-immunogold labeling shows that in MSNs, plasma membrane Kv2.1 clusters are adjacent to subsurface cisternae, placing Kv2.1 in close proximity to sites of RyR-mediated Ca2+ release. Immunofluorescence labeling in transgenic mice expressing green fluorescent protein in specific MSN populations reveals the most prominent juxtaposed Kv2.1:RyR clusters in indirect pathway MSNs. Kv2.1 in both direct and indirect pathway MSNs exhibits markedly lower levels of labeling with phosphospecific antibodies directed against the S453, S563, and S603 phosphorylation site compared with levels observed in neocortical neurons, although labeling for Kv2.1 phosphorylation at S563 was significantly lower in indirect pathway MSNs compared with those in the direct pathway. Finally, acute stimulation of RyRs in heterologous cells causes a rapid hyperpolarizing shift in the voltage dependence of activation of Kv2.1, typical of Ca2+ /calcineurin-dependent Kv2.1 dephosphorylation. Together, these studies reveal that striatal MSNs are distinct in their expression of clustered Kv2.1 at plasma membrane sites juxtaposed to intracellular RyRs, as well as in Kv2.1 phosphorylation state. Differences in Kv2.1 expression and phosphorylation between MSNs in direct and indirect pathways provide a cell- and circuit-specific mechanism for coupling intracellular Ca2+ release to phosphorylation-dependent regulation of Kv2.1 to dynamically impact intrinsic excitability.
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Affiliation(s)
- Danielle Mandikian
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California, 95616
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