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Naffa R, Hegedűs L, Hegedűs T, Tóth S, Papp B, Tordai A, Enyedi Á. Plasma membrane Ca 2+ pump isoform 4 function in cell migration and cancer metastasis. J Physiol 2024; 602:1551-1564. [PMID: 36876504 DOI: 10.1113/jp284179] [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: 12/12/2022] [Accepted: 03/02/2023] [Indexed: 03/07/2023] Open
Abstract
The Ca2+ ion is a universal second messenger involved in many vital physiological functions including cell migration and development. To fulfil these tasks the cytosolic Ca2+ concentration is tightly controlled, and this involves an intricate functional balance between a variety of channels and pumps of the Ca2+ signalling machinery. Among these proteins, plasma membrane Ca2+ ATPases (PMCAs) represent the major high-affinity Ca2+ extrusion systems in the cell membrane that are effective in maintaining free Ca2+ concentration at exceedingly low cytosolic levels, which is essential for normal cell function. An imbalance in Ca2+ signalling can have pathogenic consequences including cancer and metastasis. Recent studies have highlighted the role of PMCAs in cancer progression and have shown that a particular variant, PMCA4b, is downregulated in certain cancer types, causing delayed attenuation of the Ca2+ signal. It has also been shown that loss of PMCA4b leads to increased migration and metastasis of melanoma and gastric cancer cells. In contrast, an increased PMCA4 expression has been reported in pancreatic ductal adenocarcinoma that coincided with increased cell migration and shorter patient survival, suggesting distinct roles of PMCA4b in various tumour types and/or different stages of tumour development. The recently discovered interaction of PMCAs with basigin, an extracellular matrix metalloproteinase inducer, may provide further insights into our understanding of the specific roles of PMCA4b in tumour progression and cancer metastasis.
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Affiliation(s)
- Randa Naffa
- Molecular Biology Research Laboratory, School of Medicine, The University of Jordan, Amman, Jordan
| | - Luca Hegedűs
- Department of Thoracic Surgery, Ruhrlandklinik, University Clinic Essen, Essen, Germany
| | - Tamás Hegedűs
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
- ELKH-SE Biophysical Virology Research Group, Eötvös Loránd Research Network, Budapest, Hungary
| | - Sarolta Tóth
- Department of Transfusion Medicine, Semmelweis University, Budapest, Hungary
| | - Béla Papp
- Institut National de la Santé et de la Recherche Médicale, Institut de Recherche Saint-Louis, Hôpital Saint-Louis, Paris, France
- Institut de Recherche Saint-Louis, Hôpital Saint-Louis, Université de Paris, Paris, France
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, Paris, France
| | - Attila Tordai
- Department of Transfusion Medicine, Semmelweis University, Budapest, Hungary
| | - Ágnes Enyedi
- ELKH-SE Biophysical Virology Research Group, Eötvös Loránd Research Network, Budapest, Hungary
- Department of Transfusion Medicine, Semmelweis University, Budapest, Hungary
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2
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Durbin RJ, Heredia DJ, Gould TW, Renden RB. Postsynaptic Calcium Extrusion at the Mouse Neuromuscular Junction Alkalinizes the Synaptic Cleft. J Neurosci 2023; 43:5741-5752. [PMID: 37474311 PMCID: PMC10423045 DOI: 10.1523/jneurosci.0815-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023] Open
Abstract
Neurotransmission is shaped by extracellular pH. Alkalization enhances pH-sensitive transmitter release and receptor activation, whereas acidification inhibits these processes and can activate acid-sensitive conductances in the synaptic cleft. Previous work has shown that the synaptic cleft can either acidify because of synaptic vesicular release and/or alkalize because of Ca2+ extrusion by the plasma membrane ATPase (PMCA). The direction of change differs across synapse types. At the mammalian neuromuscular junction (NMJ), the direction and magnitude of pH transients in the synaptic cleft during transmission remain ambiguous. We set out to elucidate the extracellular pH transients that occur at this cholinergic synapse under near-physiological conditions and identify their sources. We monitored pH-dependent changes in the synaptic cleft of the mouse levator auris longus using viral expression of the pseudoratiometric probe pHusion-Ex in the muscle. Using mice from both sexes, a significant and prolonged alkalization occurred when stimulating the connected nerve for 5 s at 50 Hz, which was dependent on postsynaptic intracellular Ca2+ release. Sustained stimulation for a longer duration (20 s at 50 Hz) caused additional prolonged net acidification at the cleft. To investigate the mechanism underlying cleft alkalization, we used muscle-expressed GCaMP3 to monitor the contribution of postsynaptic Ca2+ Activity-induced liberation of intracellular Ca2+ in muscle positively correlated with alkalization of the synaptic cleft, whereas inhibiting PMCA significantly decreased the extent of cleft alkalization. Thus, cholinergic synapses of the mouse NMJ typically alkalize because of cytosolic Ca2+ liberated in muscle during activity, unless under highly strenuous conditions where acidification predominates.SIGNIFICANCE STATEMENT Changes in synaptic cleft pH alter neurotransmission, acting on receptors and channels on both sides of the synapse. Synaptic acidification has been associated with a myriad of diseases in the central and peripheral nervous system. Here, we report that in near-physiological recording conditions the cholinergic neuromuscular junction shows use-dependent bidirectional changes in synaptic cleft pH-immediate alkalinization and a long-lasting acidification under prolonged stimulation. These results provide further insight into physiologically relevant changes at cholinergic synapses that have not been defined previously. Understanding and identifying synaptic pH transients during and after neuronal activity provides insight into short-term synaptic plasticity synapses and may identify therapeutic targets for diseases.
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Affiliation(s)
- Ryan J Durbin
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Dante J Heredia
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Thomas W Gould
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Robert B Renden
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
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3
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Hamoudi W, Tripathi MK, Ojha SK, Amal H. A cross-talk between nitric oxide and the glutamatergic system in a Shank3 mouse model of autism. Free Radic Biol Med 2022; 188:83-91. [PMID: 35716826 DOI: 10.1016/j.freeradbiomed.2022.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 11/21/2022]
Abstract
Nitric oxide (NO) is a multifunctional signaling molecule that plays a crucial role in synaptic transmission and neuronal function. Pioneering studies show that nitric oxide (NO) and S-nitrosylation (SNO, the NO-mediated posttranslational modification) can engender nitrosative stress in the brain, contributing to neurodegenerative diseases. Little is known, however, about the aberrant NO signaling in neurodevelopmental disorders including autism spectrum disorder (ASD). We have recently shown that the Shank3 mutation in mice representing a model of ASD causes excessive NO levels and aberrant protein SNO. The glutamatergic system is involved in ASD, specifically in SHANK3 pathology. We used SNOTRAP technology to identify the SNO-proteome in the brain of the Shank3 mutant mice to understand the role of SNO in the glutamatergic system during the development of these mice. We conducted a systems biology analysis of the SNO-proteome to investigate the biological processes and signaling pathways in the brain of juvenile and adult Shank3 mutant and wild-type mice. The Shank3 mutation caused significant SNO-enrichment of a glutamate signaling pathway in the juvenile and adult mutant mice, although different protein subsets were S-nitrosylated in both ages. Cellular compartments analysis showed that "glutamatergic Synapse" is SNO-enriched significantly in the mutant mice of both ages. We also found eight S-nitrosylated proteins involved in glutamate transmission in both ages. 38 SNO-proteins found in the mutant mice are among the high-risk SFARI gene list. Biochemical examination shows a reduction in the levels of NMDA Receptor (NR1) in the cortex and striatum of the mutant mice of both ages. Neuronal NOS knockdown in SHSY-5Y rescued NR1 levels. In conclusion, this study reveals novel SNO of key glutamatergic proteins in Shank3 mutant mice and a cross-talk between nitric oxide and the glutamatergic system.
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Affiliation(s)
- Wajeha Hamoudi
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Manish Kumar Tripathi
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Shashank Kumar Ojha
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Haitham Amal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel.
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4
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Malci A, Lin X, Sandoval R, Gundelfinger ED, Naumann M, Seidenbecher CI, Herrera-Molina R. Ca 2+ signaling in postsynaptic neurons: Neuroplastin-65 regulates the interplay between plasma membrane Ca 2+ ATPases and ionotropic glutamate receptors. Cell Calcium 2022; 106:102623. [PMID: 35853264 DOI: 10.1016/j.ceca.2022.102623] [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: 01/30/2022] [Revised: 06/28/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022]
Abstract
Upon postsynaptic glutamate receptor activation, the cytosolic Ca2+ concentration rises and initiates signaling and plasticity in spines. The plasma membrane Ca2+ ATPase (PMCA) is a major player to limit the duration of cytosolic Ca2+ signals. It forms complexes with the glycoprotein neuroplastin (Np) isoforms Np55 and Np65 and functionally interplays with N-methyl-D-aspartate (NMDA)-type ionotropic glutamate receptors (iGluNRs). Moreover, binding of the Np65-specific extracellular domain to Ca2+-permeable GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type ionotropic glutamate receptors (iGluA1Rs) was found to be required for long-term potentiation (LTP). However, the link between PMCA and iGluRs function to regulate cytosolic Ca2+ signals remained unclear. Here, we report that Np65 coordinates PMCA and iGluRs' functions to modulate the duration and amplitude of cytosolic Ca2+ transients in dendrites and spines of hippocampal neurons. Using live-cell Ca2+ imaging, acute pharmacological treatments, and GCaMP5G-expressing hippocampal neurons, we discovered that endogenous or Np65-promoted PMCA activity contributes to the restoration of basal Ca2+ levels and that this effect is dependent on iGluR activation. Super-resolution STED and confocal microscopy revealed that electrical stimulation increases the abundance of synaptic neuroplastin-PMCA complexes depending on iGluR activation and that low-rate overexpression of Np65 doubled PMCA levels and decreased cell surface levels of GluN2A and GluA1 in dendrites and Shank2-positive glutamatergic synapses. In neuroplastin-deficient hippocampi, we observed reduced PMCA and unchanged GluN2B levels, while GluN2A and GluA1 levels were imbalanced. Our electrophysiological data from hippocampal slices argues for an essential interplay of PMCA with GluN2A- but not with GluN2B-containing receptors upon induction of synaptic plasticity. Accordingly, we conclude that Np65 may interconnect PMCA with core players of glutamatergic neurotransmission to fine-tune the Ca2+ signal regulation in basal synaptic function and plasticity.
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Affiliation(s)
- Ayse Malci
- Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Xiao Lin
- Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Rodrigo Sandoval
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Eckart D Gundelfinger
- Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany; Institute of Pharmacology and Toxicology, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Constanze I Seidenbecher
- Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Rodrigo Herrera-Molina
- Center for Behavioral Brain Sciences, Magdeburg, Germany; Centro Integrativo de Biología y Química Aplicada, Universidad Bernardo O'Higgins, Santiago, Chile; Combinatorial Combinatorial NeuroImaging (CNI), Leibniz Institute for Neurobiology, Magdeburg, Germany.
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5
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Ilic K, Mlinac-Jerkovic K, Sedmak G, Rosenzweig I, Kalanj-Bognar S. Neuroplastin in human cognition: review of literature and future perspectives. Transl Psychiatry 2021; 11:394. [PMID: 34282131 PMCID: PMC8289873 DOI: 10.1038/s41398-021-01509-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 06/16/2021] [Accepted: 06/23/2021] [Indexed: 02/07/2023] Open
Abstract
Synaptic glycoprotein neuroplastin is involved in synaptic plasticity and complex molecular events underlying learning and memory. Studies in mice and rats suggest that neuroplastin is essential for cognition, as it is needed for long-term potentiation and associative memory formation. Recently, it was found that some of the effects of neuroplastin are related to regulation of calcium homeostasis through interactions with plasma membrane calcium ATPases. Neuroplastin is increasingly seen as a key factor in complex brain functions, but studies in humans remain scarce. Here we summarize present knowledge about neuroplastin in human tissues and argue its genetic association with cortical thickness, intelligence, schizophrenia, and autism; specific immunolocalization depicting hippocampal trisynaptic pathway; potential role in tissue compensatory response in neurodegeneration; and high, almost housekeeping, level of spatio-temporal gene expression in the human brain. We also propose that neuroplastin acts as a housekeeper of neuroplasticity, and that it may be considered as an important novel cognition-related molecule in humans. Several promising directions for future investigations are suggested, which may complete our understanding of neuroplastin actions in molecular basis of human cognition.
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Affiliation(s)
- Katarina Ilic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia
| | - Kristina Mlinac-Jerkovic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia
| | - Goran Sedmak
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia
| | - Ivana Rosenzweig
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London (KCL), Strand, London, WC2R 2LS, UK
- Sleep Disorders Centre, Guy's and St Thomas' Hospital, Great Maze Pond, London, SE1 9RT, UK
| | - Svjetlana Kalanj-Bognar
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia.
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6
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Hu E, Mergenthal A, Bingham CS, Song D, Bouteiller JM, Berger TW. A Glutamatergic Spine Model to Enable Multi-Scale Modeling of Nonlinear Calcium Dynamics. Front Comput Neurosci 2018; 12:58. [PMID: 30100870 PMCID: PMC6072875 DOI: 10.3389/fncom.2018.00058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 07/05/2018] [Indexed: 11/30/2022] Open
Abstract
In synapses, calcium is required for modulating synaptic transmission, plasticity, synaptogenesis, and synaptic pruning. The regulation of calcium dynamics within neurons involves cellular mechanisms such as synaptically activated channels and pumps, calcium buffers, and calcium sequestrating organelles. Many experimental studies tend to focus on only one or a small number of these mechanisms, as technical limitations make it difficult to observe all features at once. Computational modeling enables incorporation of many of these properties together, allowing for more complete and integrated studies. However, the scale of existing detailed models is often limited to synaptic and dendritic compartments as the computational burden rapidly increases when these models are integrated in cellular or network level simulations. In this article we present a computational model of calcium dynamics at the postsynaptic spine of a CA1 pyramidal neuron, as well as a methodology that enables its implementation in multi-scale, large-scale simulations. We first present a mechanistic model that includes individually validated models of various components involved in the regulation of calcium at the spine. We validated our mechanistic model by comparing simulated calcium levels to experimental data found in the literature. We performed additional simulations with the mechanistic model to determine how the simulated calcium activity varies with respect to presynaptic-postsynaptic stimulation intervals and spine distance from the soma. We then developed an input-output (IO) model that complements the mechanistic calcium model and provide a computationally efficient representation for use in larger scale modeling studies; we show the performance of the IO model compared to the mechanistic model in terms of accuracy and speed. The models presented here help achieve two objectives. First, the mechanistic model provides a comprehensive platform to describe spine calcium dynamics based on individual contributing factors. Second, the IO model is trained on the main dynamical features of the mechanistic model and enables nonlinear spine calcium modeling on the cell and network level simulation scales. Utilizing both model representations provide a multi-level perspective on calcium dynamics, originating from the molecular interactions at spines and propagating the effects to higher levels of activity involved in network behavior.
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Affiliation(s)
- Eric Hu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Adam Mergenthal
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Clayton S Bingham
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Dong Song
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Jean-Marie Bouteiller
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Theodore W Berger
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
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7
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Strehler EE, Thayer SA. Evidence for a role of plasma membrane calcium pumps in neurodegenerative disease: Recent developments. Neurosci Lett 2018; 663:39-47. [PMID: 28827127 PMCID: PMC5816698 DOI: 10.1016/j.neulet.2017.08.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/09/2017] [Accepted: 08/14/2017] [Indexed: 01/20/2023]
Abstract
Plasma membrane Ca2+ ATPases (PMCAs) are a major system for calcium extrusion from all cells. Different PMCA isoforms and splice variants are involved in the precise temporal and spatial handling of Ca2+ signals and the re-establishment of resting Ca2+ levels in the nervous system. Lack or inappropriate expression of specific PMCAs leads to characteristic neuronal phenotypes, which may be reciprocally exacerbated by genetic predisposition through alleles in other genes that modify PMCA interactions, regulation, and function. PMCA dysfunction is often poorly compensated in neurons and may lead to changes in synaptic transmission, altered excitability and, with long-term calcium overload, eventual cell death. Decrease and functional decline of PMCAs are hallmarks of neurodegeneration during aging, and mutations in specific PMCAs are responsible for neuronal dysfunction and accelerated neurodegeneration in many sensory and cognitive diseases.
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Affiliation(s)
- Emanuel E Strehler
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA; Department of Biomedicine, University of Basel, Basel, Switzerland.
| | - Stanley A Thayer
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN, USA.
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8
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Fogarty MJ, Mu EWH, Lavidis NA, Noakes PG, Bellingham MC. Motor Areas Show Altered Dendritic Structure in an Amyotrophic Lateral Sclerosis Mouse Model. Front Neurosci 2017; 11:609. [PMID: 29163013 PMCID: PMC5672020 DOI: 10.3389/fnins.2017.00609] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/18/2017] [Indexed: 12/11/2022] Open
Abstract
Objective: Motor neurons (MNs) die in amyotrophic lateral sclerosis (ALS), a clinically heterogeneous neurodegenerative disease of unknown etiology. In human or rodent studies, MN loss is preceded by increased excitability. As increased neuronal excitability correlates with structural changes in dendritic arbors and spines, we have examined longitudinal changes in dendritic structure in vulnerable neuron populations in a mouse model of familial ALS. Methods: We used a modified Golgi-Cox staining method to determine the progressive changes in dendritic structure of hippocampal CA1 pyramidal neurons, striatal medium spiny neurons, and resistant (trochlear, IV) or susceptible (hypoglossal, XII; lumbar) MNs from brainstem and spinal cord of mice over-expressing the human SOD1G93A (SOD1) mutation, in comparison to wild-type (WT) mice, at four postnatal (P) ages of 8–15, 28–35, 65–75, and 120 days. Results: In SOD1 mice, dendritic changes occur at pre-symptomatic ages in both XII and spinal cord lumbar MNs. Spine loss without dendritic changes was present in striatal neurons from disease onset. Spine density increases were present at all ages studied in SOD1 XII MNs. Spine density increased in neonatal lumbar MNs, before decreasing to control levels by P28-35 and was decreased by P120. SOD1 XII MNs and lumbar MNs, but not trochlear MNs showed vacuolization from the same time-points. Trochlear MN dendrites were unchanged. Interpretation: Dendritic structure and spine alterations correlate with the neuro-motor phenotype in ALS and with cognitive and extra-motor symptoms seen in patients. Prominent early changes in dendritic arbors and spines occur in susceptible cranial and spinal cord MNs, but are absent in MNs resistant to loss in ALS.
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Affiliation(s)
- Matthew J Fogarty
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Erica W H Mu
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Nickolas A Lavidis
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Peter G Noakes
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia.,Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia
| | - Mark C Bellingham
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
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9
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Herrera-Molina R, Mlinac-Jerkovic K, Ilic K, Stöber F, Vemula SK, Sandoval M, Milosevic NJ, Simic G, Smalla KH, Goldschmidt J, Bognar SK, Montag D. Neuroplastin deletion in glutamatergic neurons impairs selective brain functions and calcium regulation: implication for cognitive deterioration. Sci Rep 2017; 7:7273. [PMID: 28779130 PMCID: PMC5544750 DOI: 10.1038/s41598-017-07839-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/26/2017] [Indexed: 02/05/2023] Open
Abstract
The cell adhesion molecule neuroplastin (Np) is a novel candidate to influence human intelligence. Np-deficient mice display complex cognitive deficits and reduced levels of Plasma Membrane Ca2+ ATPases (PMCAs), an essential regulator of the intracellular Ca2+ concentration ([iCa2+]) and neuronal activity. We show abundant expression and conserved cellular and molecular features of Np in glutamatergic neurons in human hippocampal-cortical pathways as characterized for the rodent brain. In Nptnlox/loxEmx1Cre mice, glutamatergic neuron-selective Np ablation resulted in behavioral deficits indicating hippocampal, striatal, and sensorimotor dysfunction paralleled by highly altered activities in hippocampal CA1 area, sensorimotor cortex layers I-III/IV, and the striatal sensorimotor domain detected by single-photon emission computed tomography. Altered hippocampal and cortical activities correlated with reduction of distinct PMCA paralogs in Nptnlox/loxEmx1Cre mice and increased [iCa2+] in cultured mutant neurons. Human and rodent Np enhanced the post-transcriptional expression of and co-localized with PMCA paralogs in the plasma membrane of transfected cells. Our results indicate Np as essential for PMCA expression in glutamatergic neurons allowing proper [iCa2+] regulation and normal circuit activity. Neuron-type-specific Np ablation empowers the investigation of circuit-coded learning and memory and identification of causal mechanisms leading to cognitive deterioration.
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Affiliation(s)
- Rodrigo Herrera-Molina
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Kristina Mlinac-Jerkovic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Katarina Ilic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Franziska Stöber
- Department of Systems Physiology; Special Laboratories, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Sampath Kumar Vemula
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Mauricio Sandoval
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Natasa Jovanov Milosevic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Goran Simic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Karl-Heinz Smalla
- Department of Molecular Biology Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Jürgen Goldschmidt
- Department of Systems Physiology; Special Laboratories, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Svjetlana Kalanj Bognar
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Dirk Montag
- Neurogenetics, Leibniz Institute for Neurobiology, Magdeburg, Germany.
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10
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Calcium as a Trojan horse in mental diseases-The role of PMCA and PMCA-interacting proteins in bipolar disorder and schizophrenia. Neurosci Lett 2017; 663:48-54. [PMID: 28780170 DOI: 10.1016/j.neulet.2017.08.005] [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: 06/28/2017] [Revised: 07/30/2017] [Accepted: 08/01/2017] [Indexed: 01/01/2023]
Abstract
Although first mentions about calcium disturbances in psychiatric diseases appeared more than 30 years ago, the most recent genomic and proteomic findings confirmed a significant role of Ca2+ and Ca2+-regulated pathways in development of neuropathological processes, including bipolar disorder and schizophrenia. Moreover, last decades have shown that due to multifactorial nature of both diseases, impairment in neuronal calcium homeostasis may depend not only on disturbed Ca2+ entry system, but also on altered extrusion system. A pivotal role in Ca2+ clearance mechanism is played by plasma membrane Ca2+-ATPase (PMCA), the enzyme responsible for returning the elevated levels of cytosolic Ca2+ back to the resting state. In this paper we summarize the current knowledge about the role of PMCA in bipolar disorder and schizophrenia pathologies, as well as the contribution of several proteins that by interaction with PMCA modify signal transduction mechanisms.
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11
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Khariv V, Elkabes S. Contribution of Plasma Membrane Calcium ATPases to neuronal maladaptive responses: Focus on spinal nociceptive mechanisms and neurodegeneration. Neurosci Lett 2017; 663:60-65. [PMID: 28780172 DOI: 10.1016/j.neulet.2017.08.003] [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: 05/24/2017] [Revised: 07/10/2017] [Accepted: 08/01/2017] [Indexed: 10/19/2022]
Abstract
Plasma membrane calcium ATPases (PMCAs) are ion pumps that expel Ca2+ from cells and maintain Ca2+ homeostasis. Four isoforms and multiple splice variants play important and non-overlapping roles in cellular function and integrity and have been implicated in diseases including disorders of the central nervous system (CNS). In particular, one of these isoforms, PMCA2, is critical for spinal cord (SC) neuronal function. PMCA2 expression is decreased in SC neurons at onset of symptoms in animal models of multiple sclerosis. Decreased PMCA2 expression affects the function and viability of SC neurons, with motor neurons being the most vulnerable population. Recent studies have also shown that PMCA2 could be an important contributor to pain processing in the dorsal horn (DH) of the SC. Pain sensitivity was altered in female, but not male, PMCA2+/- mice compared to PMCA2+/+ littermates in a modality-dependent manner. Changes in pain responsiveness in the female PMCA2+/- mice were paralleled by female-specific alterations in the expression of effectors, which have been implicated in the excitability of DH neurons, in mechanisms governing nociception and in the transmission of pain signals. Other PMCA isoforms and in particular, PMCA4, also contribute to the excitability of neurons in the dorsal root ganglia (DRG), which contain the first-order sensory neurons that convey nociceptive information from the periphery to the DH. These findings suggest that specific PMCA isoforms play specialized functions in neurons that mediate pain processing. Further investigations are necessary to unravel the precise contribution of PMCAs to mechanisms governing pathological pain in models of injury and disease.
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Affiliation(s)
- Veronika Khariv
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States; Graduate School of Biomedical Sciences, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Stella Elkabes
- Department of Neurological Surgery, Reynolds Family Spine Laboratory, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States.
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Multifaceted plasma membrane Ca(2+) pumps: From structure to intracellular Ca(2+) handling and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1351-63. [PMID: 26707182 DOI: 10.1016/j.bbamcr.2015.12.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/25/2015] [Accepted: 12/12/2015] [Indexed: 11/20/2022]
Abstract
Plasma membrane Ca(2+) ATPases (PMCAs) are intimately involved in the control of intracellular Ca(2+) concentration. They reduce Ca(2+) in the cytosol not only by direct ejection, but also by controlling the formation of inositol-1,4,5-trisphosphate and decreasing Ca(2+) release from the endoplasmic reticulum Ca(2+) pool. In mammals four genes (PMCA1-4) are expressed, and alternative RNA splicing generates more than twenty variants. The variants differ in their regulatory characteristics. They localize into highly specialized membrane compartments and respond to the incoming Ca(2+) with distinct temporal resolution. The expression pattern of variants depends on cell type; a change in this pattern can result in perturbed Ca(2+) homeostasis and thus altered cell function. Indeed, PMCAs undergo remarkable changes in their expression pattern during tumorigenesis that might significantly contribute to the unbalanced Ca(2+) homeostasis of cancer cells. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen.
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13
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Bartol TM, Keller DX, Kinney JP, Bajaj CL, Harris KM, Sejnowski TJ, Kennedy MB. Computational reconstitution of spine calcium transients from individual proteins. Front Synaptic Neurosci 2015; 7:17. [PMID: 26500546 PMCID: PMC4595661 DOI: 10.3389/fnsyn.2015.00017] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/11/2015] [Indexed: 11/24/2022] Open
Abstract
We have built a stochastic model in the program MCell that simulates Ca(2+) transients in spines from the principal molecular components believed to control Ca(2+) entry and exit. Proteins, with their kinetic models, are located within two segments of dendrites containing 88 intact spines, centered in a fully reconstructed 6 × 6 × 5 μm(3) cube of hippocampal neuropil. Protein components include AMPA- and NMDA-type glutamate receptors, L- and R-type voltage-dependent Ca(2+) channels, Na(+)/Ca(2+) exchangers, plasma membrane Ca(2+) ATPases, smooth endoplasmic reticulum Ca(2+) ATPases, immobile Ca(2+) buffers, and calbindin. Kinetic models for each protein were taken from published studies of the isolated proteins in vitro. For simulation of electrical stimuli, the time course of voltage changes in the dendritic spine was generated with the desired stimulus in the program NEURON. Voltage-dependent parameters were then continuously re-adjusted during simulations in MCell to reproduce the effects of the stimulus. Nine parameters of the model were optimized within realistic experimental limits by a process that compared results of simulations to published data. We find that simulations in the optimized model reproduce the timing and amplitude of Ca(2+) transients measured experimentally in intact neurons. Thus, we demonstrate that the characteristics of individual isolated proteins determined in vitro can accurately reproduce the dynamics of experimentally measured Ca(2+) transients in spines. The model will provide a test bed for exploring the roles of additional proteins that regulate Ca(2+) influx into spines and for studying the behavior of protein targets in the spine that are regulated by Ca(2+) influx.
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Affiliation(s)
- Thomas M. Bartol
- Computational Neurobiology Laboratory, Howard Hughes Medical Institute, The Salk Institute for Biological StudiesLa Jolla, CA, USA
- Center for Theoretical Biological Physics, University of CaliforniaSan Diego, La Jolla, CA, USA
| | - Daniel X. Keller
- Center for Theoretical Biological Physics, University of CaliforniaSan Diego, La Jolla, CA, USA
- Neurosciences Department, University of CaliforniaSan Diego, La Jolla, CA, USA
| | - Justin P. Kinney
- Computational Neurobiology Laboratory, Howard Hughes Medical Institute, The Salk Institute for Biological StudiesLa Jolla, CA, USA
| | - Chandrajit L. Bajaj
- Department of Computer Science, Center for Computational Visualization, University of TexasAustin, TX, USA
| | - Kristen M. Harris
- Department of Neuroscience, Center for Learning and Memory, University of TexasAustin, TX, USA
| | - Terrence J. Sejnowski
- Computational Neurobiology Laboratory, Howard Hughes Medical Institute, The Salk Institute for Biological StudiesLa Jolla, CA, USA
- Center for Theoretical Biological Physics, University of CaliforniaSan Diego, La Jolla, CA, USA
- Division of Biological Sciences, University of CaliforniaSan Diego, La Jolla, CA, USA
| | - Mary B. Kennedy
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadena, CA, USA
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Autocrine boost of NMDAR current in hippocampal CA1 pyramidal neurons by a PMCA-dependent, perisynaptic, extracellular pH shift. J Neurosci 2015; 35:873-7. [PMID: 25609607 DOI: 10.1523/jneurosci.2293-14.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The plasma membrane Ca(2+)-ATPase (PMCA) is found near postsynaptic NMDARs. This transporter is a Ca(2+)-H(+) exchanger that raises cell surface pH. We tested whether the PMCA acts in an autocrine fashion to boost pH-sensitive, postsynaptic NMDAR currents. In mouse hippocampal slices, NMDAR EPSCs in a singly activated CA1 pyramidal neuron were reduced when buffering was augmented by exogenous carbonic anhydrase (XCAR). This effect was blocked by the enzyme inhibitor benzolamide and mimicked by the addition of HEPES buffer. Similar EPSC reduction occurred when PMCA activation was prevented by dialysis of BAPTA or the PMCA inhibitor carboxyeosin. Using HEPES, BAPTA, or carboxyeosin, the effect of XCAR was completely occluded. XCAR similarly curtailed NMDAR EPSCs of minimal amplitude, but had no effect on small AMPAR responses. These results indicate that a significant fraction of the postsynaptic NMDAR current is reliant on a perisynaptic extracellular alkaline shift generated by the PMCA.
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15
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Sala C, Segal M. Dendritic spines: the locus of structural and functional plasticity. Physiol Rev 2014; 94:141-88. [PMID: 24382885 DOI: 10.1152/physrev.00012.2013] [Citation(s) in RCA: 336] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The introduction of high-resolution time lapse imaging and molecular biological tools has changed dramatically the rate of progress towards the understanding of the complex structure-function relations in synapses of central spiny neurons. Standing issues, including the sequence of molecular and structural processes leading to formation, morphological change, and longevity of dendritic spines, as well as the functions of dendritic spines in neurological/psychiatric diseases are being addressed in a growing number of recent studies. There are still unsettled issues with respect to spine formation and plasticity: Are spines formed first, followed by synapse formation, or are synapses formed first, followed by emergence of a spine? What are the immediate and long-lasting changes in spine properties following exposure to plasticity-producing stimulation? Is spine volume/shape indicative of its function? These and other issues are addressed in this review, which highlights the complexity of molecular pathways involved in regulation of spine structure and function, and which contributes to the understanding of central synaptic interactions in health and disease.
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Penniston JT, Padányi R, Pászty K, Varga K, Hegedus L, Enyedi A. Apart from its known function, the plasma membrane Ca²⁺ATPase can regulate Ca²⁺ signaling by controlling phosphatidylinositol 4,5-bisphosphate levels. J Cell Sci 2013; 127:72-84. [PMID: 24198396 DOI: 10.1242/jcs.132548] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasma membrane Ca(2+) ATPases (PMCAs, also known as ATP2B1-ATP2B4) are known targets of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P₂], but if and how they control the PtdIns(4,5)P₂ pool has not been considered. We demonstrate here that PMCAs protect PtdIns(4,5)P₂ in the plasma membrane from hydrolysis by phospholipase C (PLC). Comparison of active and inactive PMCAs indicates that the protection operates by two mechanisms; one requiring active PMCAs, the other not. It appears that the mechanism requiring activity is the removal of the Ca(2+) required for sustained PLC activity, whereas the mechanism not requiring activity is PtdIns(4,5)P₂ binding. We show that in PMCA overexpressing cells, PtdIns(4,5)P₂ binding can lead to less inositol 1,4,5-triphosphate (InsP₃) and diminished Ca(2+) release from intracellular Ca(2+) pools. Inspection of a homology model of PMCA suggests that PMCAs have a conserved cluster of basic residues forming a 'blue collar' at the interface between the membrane core and the cytoplasmic domains. By molecular dynamics simulation, we found that the blue collar forms four binding pockets for the phosphorylated inositol head group of PtdIns(4,5)P₂; these pockets bind PtdIns(4,5)P₂ strongly and frequently. Our studies suggest that by having the ability to bind PtdIns(4,5)P₂, PMCAs can control the accessibility of PtdIns(4,5)P₂ for PLC and other PtdIns(4,5)P₂-mediated processes.
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Affiliation(s)
- John T Penniston
- Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1025 Budapest, Hungary
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Yang W, Liu J, Zheng F, Jia M, Zhao L, Lu T, Ruan Y, Zhang J, Yue W, Zhang D, Wang L. The evidence for association of ATP2B2 polymorphisms with autism in Chinese Han population. PLoS One 2013; 8:e61021. [PMID: 23620727 PMCID: PMC3631200 DOI: 10.1371/journal.pone.0061021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/05/2013] [Indexed: 12/27/2022] Open
Abstract
Background Autism is a neurodevelopmental disorder with a high estimated heritability. ATP2B2, located on human chromosome 3p25.3, encodes the plasma membrane calcium-transporting ATPase 2 which extrudes Ca2+ from cytosol into extracellular space. Recent studies reported association between ATP2B2 and autism in samples from Autism Genetic Resource Exchange (AGRE) and Italy. In this study, we investigated whether ATP2B2 polymorphisms were associated with autism in Chinese Han population. Methods We performed a family based association study between five SNPs (rs35678 in exon, rs241509, rs3774180, rs3774179, and rs2278556 in introns) in ATP2B2 and autism in 427 autism trios of Han Chinese descent. All SNPs were genotyped using the Sequenom genotyping platform. The family-based association test (FBAT) program was used to perform association test for SNPs and haplotype analyses. Results This study demonstrated a preferential transmission of T allele of rs3774179 to affected offsprings under an additive model (T>C, Z = 2.482, p = 0.013). While C allele of rs3774179 showed an undertransmission from parents to affected children under an additive and a dominant model, respectively (Z = −2.482, p = 0.013; Z = −2.591, p = 0.0096). Haplotype analyses revealed that three haplotypes were significantly associated with autism. The haplotype C-C (rs3774180–rs3774179) showed a significant undertransmission from parents to affected offsprings both in specific and global haplotype FBAT (Z = −2.037, p = 0.042; Global p = 0.03). As for the haplotype constructed by rs3774179 and rs2278556, C-A might be a protective haplotype (Z = −2.206, p = 0.027; Global p = 0.04), while T-A demonstrated an excess transmission from parents to affected offsprings (Z = 2.143, p = 0.032). These results were still significant after using the permutation method to obtain empirical p values. Conclusions Our research suggested that ATP2B2 might play a role in the etiology of autism in Chinese Han population.
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Affiliation(s)
- Wen Yang
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Jing Liu
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Fanfan Zheng
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Meixiang Jia
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Linnan Zhao
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Tianlan Lu
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Yanyan Ruan
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Jishui Zhang
- Beijing Children’s Hospital Affiliated to Capital University of Medical Sciences, Beijing, People’s Republic of China
| | - Weihua Yue
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
| | - Dai Zhang
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
- Peking-Tsinghua Center for Life Sciences, Beijing, People’s Republic of China
- * E-mail: (DZ); (LFW)
| | - Lifang Wang
- Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, People’s Republic of China
- Institute of Mental Health, Peking University, Beijing, People’s Republic of China
- * E-mail: (DZ); (LFW)
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NMDA receptor-dependent afterdepolarizations are curtailed by carbonic anhydrase 14: regulation of a short-term postsynaptic potentiation. J Neurosci 2013; 32:16754-62. [PMID: 23175829 DOI: 10.1523/jneurosci.1467-12.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the hippocampus, extracellular carbonic anhydrase (Car) speeds the buffering of an activity-generated rise in extracellular pH that impacts H(+)-sensitive NMDA receptors (NMDARs). We studied the role of Car14 in this brain structure, in which it is expressed solely on neurons. Current-clamp responses were recorded from CA1 pyramidal neurons in wild-type (WT) versus Car14 knock-out (KO) mice 2 s before (control) and after (test) a 10 pulse, 100 Hz afferent train. In both WT and KO, the half-width (HW) of the test response, and its number of spikes, were augmented relative to the control. An increase in presynaptic release was not involved, because AMPAR-mediated EPSCs were depressed after a train. The increases in HW and spike number were both greater in the Car14 KO. In 0 Mg(2+) saline with picrotoxin (using a 20 Hz train), the HW measures were still greater in the KO. The Car inhibitor benzolamide (BZ) enhanced the test response HW in the WT but had no effect on the already-prolonged HW in the KO. With intracellular MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d]-cyclohepten-5,10-imine maleate], the curtailed WT and KO responses were indistinguishable, and BZ caused no change. In contrast, the extracellular alkaline changes evoked by the train were not different between WT and KO, and BZ amplified these alkalinizations similarly. These data suggest that Car14 regulates pH transients in the perisynaptic microenvironment and govern their impact on NMDARs but plays little role in buffering pH shifts in the broader, macroscopic, extracellular space.
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Jiang L, Bechtel MD, Galeva NA, Williams TD, Michaelis EK, Michaelis ML. Decreases in plasma membrane Ca²⁺-ATPase in brain synaptic membrane rafts from aged rats. J Neurochem 2012; 123:689-99. [PMID: 22889001 DOI: 10.1111/j.1471-4159.2012.07918.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/31/2012] [Accepted: 08/07/2012] [Indexed: 12/18/2022]
Abstract
Precise regulation of free intracellular Ca(2+) concentrations [Ca(2+) ](i) is critical for normal neuronal function, and alterations in Ca(2+) homeostasis are associated with brain aging and neurodegenerative diseases. One of the most important proteins controlling [Ca(2+) ](i) is the plasma membrane Ca(2+) -ATPase (PMCA), the high-affinity transporter that fine tunes the cytosolic nanomolar levels of Ca(2+) . We previously found that PMCA protein in synaptic plasma membranes (SPMs) is decreased with advancing age and the decrease in enzyme activity is much greater than that in protein levels. In this study, we isolated raft and non-raft fractions from rat brain SPMs and used quantitative mass spectrometry to show that the specialized lipid microdomains in SPMs, the rafts, contain 60% of total PMCA, comprised all four isoforms. The raft PMCA pool had the highest specific activity and this decreased progressively with age. The reduction in PMCA protein could not account for the dramatic activity loss. Addition of excess calmodulin to the assay did not restore PMCA activity to that in young brains. Analysis of the major raft lipids revealed a slight age-related increase in cholesterol levels and such increases might enhance membrane lipid order and prevent further loss of PMCA activity.
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Affiliation(s)
- Lei Jiang
- Department of Pharmacology and Toxicology and Higuchi Biosciences Center, The University of Kansas, Lawrence, KS, USA
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20
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Fakira AK, Gaspers LD, Thomas AP, Li H, Jain MR, Elkabes S. Purkinje cell dysfunction and delayed death in plasma membrane calcium ATPase 2-heterozygous mice. Mol Cell Neurosci 2012; 51:22-31. [PMID: 22789621 DOI: 10.1016/j.mcn.2012.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 06/07/2012] [Accepted: 07/02/2012] [Indexed: 12/19/2022] Open
Abstract
Purkinje cell (PC) dysfunction or death has been implicated in a number of disorders including ataxia, autism and multiple sclerosis. Plasma membrane calcium ATPase 2 (PMCA2), an important calcium (Ca(2+)) extrusion pump that interacts with synaptic signaling complexes, is most abundantly expressed in PCs compared to other neurons. Using the PMCA2 heterozygous mouse as a model, we investigated whether a reduction in PMCA2 levels affects PC function. We focused on Ca(2+) signaling and the expression of glutamate receptors which play a key role in PC function including synaptic plasticity. We found that the amplitude of depolarization and 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid receptor (AMPAR)-mediated Ca(2+) transients are significantly higher in cultured PMCA2(+/-) PCs than in PMCA2(+/+) PCs. This is due to increased Ca(2+) influx, since P/Q type voltage-gated Ca(2+) channel (VGCC) expression was more pronounced in PCs and cerebella of PMCA2(+/-) mice and VGCC blockade prevented the elevation in amplitude. Neuronal nitric oxide synthase (nNOS) activity was higher in PMCA2(+/-) cerebella and inhibition of nNOS or the soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway, which mediates nitric oxide (NO) signaling, reduced the amplitude of Ca(2+) transients in PMCA2(+/-) PCs, in vitro. In addition, there was an age-dependent decrease in metabotropic glutamate receptor 1 (mGluR1) and AMPA receptor subunit GluR2/3 transcript and protein levels at 8 weeks of age. These changes were followed by PC loss in the 20-week-old PMCA2(+/-) mice. Our studies highlight the importance of PMCA2 in Ca(2+) signaling, glutamate receptor expression and survival of Purkinje cells.
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Affiliation(s)
- Amanda K Fakira
- Department of Neurological Surgery, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ, USA
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21
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Chen Q, Mahendrasingam S, Tickle JA, Hackney CM, Furness DN, Fettiplace R. The development, distribution and density of the plasma membrane calcium ATPase 2 calcium pump in rat cochlear hair cells. Eur J Neurosci 2012; 36:2302-10. [PMID: 22672315 DOI: 10.1111/j.1460-9568.2012.08159.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Calcium is tightly regulated in cochlear outer hair cells (OHCs). It enters mainly via mechanotransducer (MT) channels and is extruded by the plasma membrane calcium ATPase (PMCA)2 isoform of the PMCA, mutations in which cause hearing loss. To assess how pump expression matches the demands of Ca(2+) homeostasis, the distribution of PMCA2 at different cochlear locations during development was quantified using immunofluorescence and post-embedding immunogold labeling. The PMCA2 isoform was confined to stereociliary bundles, first appearing at the base of the cochlea around post-natal day (P)0 followed by the middle and then the apex by P3, and was unchanged after P8. The developmental appearance matched the maturation of the MT channels in rat OHCs. High-resolution immunogold labeling in adult rats showed that PMCA2 was distributed along the membranes of all three rows of OHC stereocilia at similar densities and at about a quarter of the density in inner hair cell stereocilia. The difference between OHCs and inner hair cells was similar to the ratio of their MT channel resting open probabilities. Gold particle counts revealed no difference in PMCA2 density between low- and high-frequency OHC bundles despite larger MT currents in high-frequency OHCs. The PMCA2 density in OHC stereocilia was determined in low- and high-frequency regions from calibration of immunogold particle counts as 2200/μm(2) from which an extrusion rate of ∼200 ions/s per pump was inferred. The limited ability of PMCA2 to extrude the Ca(2+) load through MT channels may constitute a major cause of OHC vulnerability and high-frequency hearing loss.
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Affiliation(s)
- Qingguo Chen
- Department of Otolaryngology - Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Harris KM, Weinberg RJ. Ultrastructure of synapses in the mammalian brain. Cold Spring Harb Perspect Biol 2012; 4:cshperspect.a005587. [PMID: 22357909 DOI: 10.1101/cshperspect.a005587] [Citation(s) in RCA: 275] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The morphology and molecular composition of synapses provide the structural basis for synaptic function. This article reviews the electron microscopy of excitatory synapses on dendritic spines, using data from rodent hippocampus, cerebral cortex, and cerebellar cortex. Excitatory synapses have a prominent postsynaptic density, in contrast with inhibitory synapses, which have less dense presynaptic or postsynaptic specializations and are usually found on the cell body or proximal dendritic shaft. Immunogold labeling shows that the presynaptic active zone provides a scaffold for key molecules involved in the release of neurotransmitter, whereas the postsynaptic density contains ligand-gated ionic channels, other receptors, and a complex network of signaling molecules. Delineating the structure and molecular organization of these axospinous synapses represents a crucial step toward understanding the mechanisms that underlie synaptic transmission and the dynamic modulation of neurotransmission associated with short- and long-term synaptic plasticity.
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Affiliation(s)
- Kristen M Harris
- Center for Learning and Memory, Neurobiology Section, University of Texas, Austin, 78712, USA.
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Abstract
Calcium (Ca(2+)) is a ubiquitous signaling molecule that accumulates in the cytoplasm in response to diverse classes of stimuli and, in turn, regulates many aspects of cell function. In neurons, Ca(2+) influx in response to action potentials or synaptic stimulation triggers neurotransmitter release, modulates ion channels, induces synaptic plasticity, and activates transcription. In this article, we discuss the factors that regulate Ca(2+) signaling in mammalian neurons with a particular focus on Ca(2+) signaling within dendritic spines. This includes consideration of the routes of entry and exit of Ca(2+), the cellular mechanisms that establish the temporal and spatial profile of Ca(2+) signaling, and the biophysical criteria that determine which downstream signals are activated when Ca(2+) accumulates in a spine. Furthermore, we also briefly discuss the technical advances that made possible the quantitative study of Ca(2+) signaling in dendritic spines.
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Affiliation(s)
- Michael J Higley
- Department of Neurobiology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, Connecticut 06520, USA
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Plasma membrane calcium pump (PMCA) isoform 4 is targeted to the apical membrane by the w-splice insert from PMCA2. Cell Calcium 2012; 51:171-8. [PMID: 22252018 DOI: 10.1016/j.ceca.2011.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 11/23/2011] [Accepted: 12/13/2011] [Indexed: 11/24/2022]
Abstract
Local Ca(2+) signaling requires proper targeting of the Ca(2+) signaling toolkit to specific cellular locales. Different isoforms of the plasma membrane Ca(2+) pump (PMCA) are responsible for Ca(2+) extrusion at the apical and basolateral membrane of polarized epithelial cells, but the mechanisms and signals for differential targeting of the PMCAs are not well understood. Recent work demonstrated that the alternatively spliced w-insert in PMCA2 directs this pump to the apical membrane. We now show that inserting the w-insert into the corresponding location of the PMCA4 isoform confers apical targeting to this normally basolateral pump. Mutation of a di-leucine motif in the C-tail thought to be important for basolateral targeting did not enhance apical localization of the chimeric PMCA4(2w)/b. In contrast, replacing the C-terminal Val residue by Leu to optimize the PDZ ligand site for interaction with the scaffolding protein NHERF2 enhanced the apical localization of PMCA4(2w)/b, but not of PMCA4x/b. Functional studies showed that both apical PMCA4(2w)/b and basolateral PMCA4x/b handled ATP-induced Ca(2+) signals with similar kinetics, suggesting that isoform-specific functional characteristics are retained irrespective of membrane targeting. Our results demonstrate that the alternatively spliced w-insert provides autonomous apical targeting information in the PMCA without altering its functional characteristics.
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