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Ramirez-Franco J, Debreux K, Sangiardi M, Belghazi M, Kim Y, Lee SH, Lévêque C, Seagar M, El Far O. The downregulation of Kv 1 channels in Lgi1 -/-mice is accompanied by a profound modification of its interactome and a parallel decrease in Kv 2 channels. Neurobiol Dis 2024; 196:106513. [PMID: 38663634 DOI: 10.1016/j.nbd.2024.106513] [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: 11/08/2023] [Revised: 03/12/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024] Open
Abstract
In animal models of LGI1-dependent autosomal dominant lateral temporal lobe epilepsy, Kv1 channels are downregulated, suggesting their crucial involvement in epileptogenesis. The molecular basis of Kv1 channel-downregulation in LGI1 knock-out mice has not been elucidated and how the absence of this extracellular protein induces an important modification in the expression of Kv1 remains unknown. In this study we analyse by immunofluorescence the modifications in neuronal Kv1.1 and Kv1.2 distribution throughout the hippocampal formation of LGI1 knock-out mice. We show that Kv1 downregulation is not restricted to the axonal compartment, but also takes place in the somatodendritic region and is accompanied by a drastic decrease in Kv2 expression levels. Moreover, we find that the downregulation of these Kv channels is associated with a marked increase in bursting patterns. Finally, mass spectrometry uncovered key modifications in the Kv1 interactome that highlight the epileptogenic implication of Kv1 downregulation in LGI1 knock-out animals.
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Affiliation(s)
- Jorge Ramirez-Franco
- INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse, Aix-Marseille Université, 13015 Marseille, France.
| | - Kévin Debreux
- INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse, Aix-Marseille Université, 13015 Marseille, France
| | - Marion Sangiardi
- INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse, Aix-Marseille Université, 13015 Marseille, France
| | - Maya Belghazi
- Marseille Protéomique (MaP), Plateforme Protéomique IMM, CNRS FR3479, Aix-Marseille Université, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Yujin Kim
- Department of Physiology, Cell Physiology Lab, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 03080, South Korea
| | - Suk-Ho Lee
- Department of Physiology, Cell Physiology Lab, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 03080, South Korea
| | - Christian Lévêque
- INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse, Aix-Marseille Université, 13015 Marseille, France
| | - Michael Seagar
- INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse, Aix-Marseille Université, 13015 Marseille, France
| | - Oussama El Far
- INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse, Aix-Marseille Université, 13015 Marseille, France.
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2
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Park DJ, Kang JB, Koh PO. Epigallocatechin gallate improves neuronal damage in animal model of ischemic stroke and glutamate-exposed neurons via modulation of hippocalcin expression. PLoS One 2024; 19:e0299042. [PMID: 38427657 PMCID: PMC10906901 DOI: 10.1371/journal.pone.0299042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 02/02/2024] [Indexed: 03/03/2024] Open
Abstract
Epigallocatechin gallate (EGCG) is a polyphenolic component of green tea that has anti-oxidative and anti-inflammatory effects in neurons. Ischemic stroke is a major neurological disease that causes irreversible brain disorders. It increases the intracellular calcium concentration and induces apoptosis. The regulation of intracellular calcium concentration is important to maintain the function of the nervous system. Hippocalcin is a neuronal calcium sensor protein that controls intracellular calcium concentration. We investigated whether EGCG treatment regulates the expression of hippocalcin in stroke animal model and glutamate-induced neuronal damage. We performed middle cerebral artery occlusion (MCAO) to induce cerebral ischemia. EGCG (50 mg/kg) or phosphate buffered saline was injected into the abdominal cavity just before MCAO surgery. The neurobehavioral tests were performed 24 h after MCAO surgery and cerebral cortex tissue was collected. MCAO damage induced severe neurobehavioral disorders, increased infarct volume, and decreased the expression of hippocalcin in the cerebral cortex. However, EGCG treatment improved these deficits and alleviated the decrease in hippocalcin expression in cerebral cortex. In addition, EGCG dose-dependently alleviated neuronal cell death and intracellular calcium overload in glutamate-exposed neurons. Glutamate exposure reduced hippocalcin expression, decreased Bcl-2 expression, and increased Bax expression. However, EGCG treatment mitigated these changes caused by glutamate toxicity. EGCG also attenuated the increase in caspase-3 and cleaved caspase-3 expressions caused by glutamate exposure. The effect of EGCG was more pronounced in non-transfected cells than in hippocalcin siRNA-transfected cells. These findings demonstrate that EGCG protects neurons against glutamate toxicity through the regulation of Bcl-2 family proteins and caspase-3. It is known that hippocalcin exerts anti-apoptotic effect through the modulation of apoptotic pathway. Thus, we can suggest evidence that EGCG has a neuroprotective effect by regulating hippocalcin expression in ischemic brain damage and glutamate-exposed cells.
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Affiliation(s)
- Dong-Ju Park
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea
| | - Ju-Bin Kang
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea
| | - Phil-Ok Koh
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea
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3
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Singh KV, Arya R, Nirala JP, Sahu D, Nanda RK, Rajamani P. Effects of mobile phone electromagnetic radiation on rat hippocampus proteome. ENVIRONMENTAL TOXICOLOGY 2022; 37:836-847. [PMID: 34984797 DOI: 10.1002/tox.23447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 12/14/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Worldwide, the number of mobile phone users has increased from 5.57 billion in 2011 to 6.8 billion in 2019. However, short- and long-term impact of the electromagnetic radiation emitting from mobile phones on tissue homeostasis with particular to brain proteome composition needs further investigation. In this study, we attempted a global proteome profiling study of rat hippocampus exposed to mobile phone radiation for 20 weeks (for 3 h/day for 5 days/week) to identify deregulated proteins and western blot analysis for validation. As a result, we identified 358 hippocampus proteins, of which 16 showed deregulation (log2 (exposed/sham) ≥ ±1.0, p-value <.05). Majority of these deregulated proteins grouped into three clusters sharing similar molecular pathways. A set of four proteins (Succinate-semialdehyde dehydrogenase: Aldh5a1, Na+ K+ transporting ATPase: Atp1b2, plasma membrane calcium transporting ATPase: PMCA and protein S100B) presenting each functional pathway were selected for validation. Western blot analysis of these proteins, in an independent sample set, corroborated the mass spectrometry findings. Aldh5a1 involve in cellular energy metabolism, both Atp1b2 and PMCA responsible for membrane transport and protein S100B have a neuroprotective role. In conclusion, we present a deregulated hippocampus proteome upon mobile phone radiation exposure, which might influence the healthy functioning of the brain.
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Affiliation(s)
| | - Rakesh Arya
- Translational Health Group, International Center for Genetic Engineering and Biotechnology, New Delhi, India
- School of Life Sciences, Sambalpur University, Jyoti Vihar, Odisha, India
| | - Jay Prakash Nirala
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Debasis Sahu
- Product Development Cell, National Institute of Immunology, New Delhi, India
| | - Ranjan Kumar Nanda
- Translational Health Group, International Center for Genetic Engineering and Biotechnology, New Delhi, India
| | - Paulraj Rajamani
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
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4
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Calpain Inhibitors as Potential Therapeutic Modulators in Neurodegenerative Diseases. Neurochem Res 2022; 47:1125-1149. [PMID: 34982393 DOI: 10.1007/s11064-021-03521-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 02/07/2023]
Abstract
It is considered a significant challenge to understand the neuronal cell death mechanisms with a suitable cure for neurodegenerative disorders in the coming years. Calpains are one of the best-considered "cysteine proteases activated" in brain disorders. Calpain is an important marker and mediator in the pathophysiology of neurodegeneration. Calpain activation being the essential neurodegenerative factor causing apoptotic machinery activation, it is crucial to develop reliable and effective approaches to prevent calpain-mediated apoptosis in degenerating neurons. It has been recently seen that the "inhibition of calpain activation" has appeared as a possible therapeutic target for managing neurodegenerative diseases. A systematic literature review of PubMed, Medline, Bentham, Scopus, and EMBASE (Elsevier) databases was conducted. The present article reviews the basic pathobiology and role of selective calpain inhibitors used in various neurodegenerative diseases as a therapeutic target.
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Schultz B, Taday J, Menezes L, Cigerce A, Leite MC, Gonçalves CA. Calpain-Mediated Alterations in Astrocytes Before and During Amyloid Chaos in Alzheimer's Disease. J Alzheimers Dis 2021; 84:1415-1430. [PMID: 34719501 DOI: 10.3233/jad-215182] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
One of the changes found in the brain in Alzheimer's disease (AD) is increased calpain, derived from calcium dysregulation, oxidative stress, and/or neuroinflammation, which are all assumed to be basic pillars in neurodegenerative diseases. The role of calpain in synaptic plasticity, neuronal death, and AD has been discussed in some reviews. However, astrocytic calpain changes sometimes appear to be secondary and consequent to neuronal damage in AD. Herein, we explore the possibility of calpain-mediated astroglial reactivity in AD, both preceding and during the amyloid phase. We discuss the types of brain calpains but focus the review on calpains 1 and 2 and some important targets in astrocytes. We address the signaling involved in controlling calpain expression, mainly involving p38/mitogen-activated protein kinase and calcineurin, as well as how calpain regulates the expression of proteins involved in astroglial reactivity through calcineurin and cyclin-dependent kinase 5. Throughout the text, we have tried to provide evidence of the connection between the alterations caused by calpain and the metabolic changes associated with AD. In addition, we discuss the possibility that calpain mediates amyloid-β clearance in astrocytes, as opposed to amyloid-β accumulation in neurons.
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Affiliation(s)
- Bruna Schultz
- Postgraduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Jéssica Taday
- Postgraduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Leonardo Menezes
- Postgraduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Anderson Cigerce
- Postgraduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Marina C Leite
- Postgraduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Carlos-Alberto Gonçalves
- Postgraduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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6
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Hwang SM, Lee JY, Park CK, Kim YH. The Role of TRP Channels and PMCA in Brain Disorders: Intracellular Calcium and pH Homeostasis. Front Cell Dev Biol 2021; 9:584388. [PMID: 33585474 PMCID: PMC7876282 DOI: 10.3389/fcell.2021.584388] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 01/06/2021] [Indexed: 12/19/2022] Open
Abstract
Brain disorders include neurodegenerative diseases (NDs) with different conditions that primarily affect the neurons and glia in the brain. However, the risk factors and pathophysiological mechanisms of NDs have not been fully elucidated. Homeostasis of intracellular Ca2+ concentration and intracellular pH (pHi) is crucial for cell function. The regulatory processes of these ionic mechanisms may be absent or excessive in pathological conditions, leading to a loss of cell death in distinct regions of ND patients. Herein, we review the potential involvement of transient receptor potential (TRP) channels in NDs, where disrupted Ca2+ homeostasis leads to cell death. The capability of TRP channels to restore or excite the cell through Ca2+ regulation depending on the level of plasma membrane Ca2+ ATPase (PMCA) activity is discussed in detail. As PMCA simultaneously affects intracellular Ca2+ regulation as well as pHi, TRP channels and PMCA thus play vital roles in modulating ionic homeostasis in various cell types or specific regions of the brain where the TRP channels and PMCA are expressed. For this reason, the dysfunction of TRP channels and/or PMCA under pathological conditions disrupts neuronal homeostasis due to abnormal Ca2+ and pH levels in the brain, resulting in various NDs. This review addresses the function of TRP channels and PMCA in controlling intracellular Ca2+ and pH, which may provide novel targets for treating NDs.
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Affiliation(s)
- Sung-Min Hwang
- Gachon Pain Center, Department of Physiology, Gachon University College of Medicine, Incheon, South Korea
| | - Ji Yeon Lee
- Gil Medical Center, Department of Anesthesiology and Pain Medicine, Gachon University, Incheon, South Korea
| | - Chul-Kyu Park
- Gachon Pain Center, Department of Physiology, Gachon University College of Medicine, Incheon, South Korea
| | - Yong Ho Kim
- Gachon Pain Center, Department of Physiology, Gachon University College of Medicine, Incheon, South Korea
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7
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Ahad MA, Kumaran KR, Ning T, Mansor NI, Effendy MA, Damodaran T, Lingam K, Wahab HA, Nordin N, Liao P, Müller CP, Hassan Z. Insights into the neuropathology of cerebral ischemia and its mechanisms. Rev Neurosci 2020; 31:521-538. [DOI: 10.1515/revneuro-2019-0099] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/09/2020] [Indexed: 11/15/2022]
Abstract
AbstractCerebral ischemia is a result of insufficient blood flow to the brain. It leads to limited supply of oxygen and other nutrients to meet metabolic demands. These phenomena lead to brain damage. There are two types of cerebral ischemia: focal and global ischemia. This condition has significant impact on patient’s health and health care system requirements. Animal models such as transient occlusion of the middle cerebral artery and permanent occlusion of extracranial vessels have been established to mimic the conditions of the respective type of cerebral ischemia and to further understand pathophysiological mechanisms of these ischemic conditions. It is important to understand the pathophysiology of cerebral ischemia in order to identify therapeutic strategies for prevention and treatment. Here, we review the neuropathologies that are caused by cerebral ischemia and discuss the mechanisms that occur in cerebral ischemia such as reduction of cerebral blood flow, hippocampal damage, white matter lesions, neuronal cell death, cholinergic dysfunction, excitotoxicity, calcium overload, cytotoxic oedema, a decline in adenosine triphosphate (ATP), malfunctioning of Na+/K+-ATPase, and the blood-brain barrier breakdown. Altogether, the information provided can be used to guide therapeutic strategies for cerebral ischemia.
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Affiliation(s)
- Mohamad Anuar Ahad
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Kesevan Rajah Kumaran
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Tiang Ning
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Nur Izzati Mansor
- Medical Genetics Unit, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
- Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | | | - Thenmoly Damodaran
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Kamilla Lingam
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Habibah Abdul Wahab
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia
- USM-RIKEN Centre for Aging Science (URICAS), Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
| | - Norshariza Nordin
- Medical Genetics Unit, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
- Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Ping Liao
- Calcium Signaling Laboratory, National Neuroscience Institute, Singapore 308433, Singapore
| | - Christian P. Müller
- Section of Addiction Medicine, Department of Psychiatry and Psychotherapy, University Clinic, Friedrich Alexander University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Zurina Hassan
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
- USM-RIKEN Centre for Aging Science (URICAS), Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
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8
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Chen J, Sitsel A, Benoy V, Sepúlveda MR, Vangheluwe P. Primary Active Ca 2+ Transport Systems in Health and Disease. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035113. [PMID: 31501194 DOI: 10.1101/cshperspect.a035113] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium ions (Ca2+) are prominent cell signaling effectors that regulate a wide variety of cellular processes. Among the different players in Ca2+ homeostasis, primary active Ca2+ transporters are responsible for keeping low basal Ca2+ levels in the cytosol while establishing steep Ca2+ gradients across intracellular membranes or the plasma membrane. This review summarizes our current knowledge on the three types of primary active Ca2+-ATPases: the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pumps, the secretory pathway Ca2+- ATPase (SPCA) isoforms, and the plasma membrane Ca2+-ATPase (PMCA) Ca2+-transporters. We first discuss the Ca2+ transport mechanism of SERCA1a, which serves as a reference to describe the Ca2+ transport of other Ca2+ pumps. We further highlight the common and unique features of each isoform and review their structure-function relationship, expression pattern, regulatory mechanisms, and specific physiological roles. Finally, we discuss the increasing genetic and in vivo evidence that links the dysfunction of specific Ca2+-ATPase isoforms to a broad range of human pathologies, and highlight emerging therapeutic strategies that target Ca2+ pumps.
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Affiliation(s)
- Jialin Chen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Aljona Sitsel
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Veronick Benoy
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - M Rosario Sepúlveda
- Department of Cell Biology, Faculty of Sciences, University of Granada, 18071 Granada, Spain
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
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9
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Ceprian M, Fulton D. Glial Cell AMPA Receptors in Nervous System Health, Injury and Disease. Int J Mol Sci 2019; 20:E2450. [PMID: 31108947 PMCID: PMC6566241 DOI: 10.3390/ijms20102450] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/11/2019] [Accepted: 04/22/2019] [Indexed: 12/16/2022] Open
Abstract
Glia form a central component of the nervous system whose varied activities sustain an environment that is optimised for healthy development and neuronal function. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA)-type glutamate receptors (AMPAR) are a central mediator of glutamatergic excitatory synaptic transmission, yet they are also expressed in a wide range of glial cells where they influence a variety of important cellular functions. AMPAR enable glial cells to sense the activity of neighbouring axons and synapses, and as such many aspects of glial cell development and function are influenced by the activity of neural circuits. However, these AMPAR also render glia sensitive to elevations of the extracellular concentration of glutamate, which are associated with a broad range of pathological conditions. Excessive activation of AMPAR under these conditions may induce excitotoxic injury in glial cells, and trigger pathophysiological responses threatening other neural cells and amplifying ongoing disease processes. The aim of this review is to gather information on AMPAR function from across the broad diversity of glial cells, identify their contribution to pathophysiological processes, and highlight new areas of research whose progress may increase our understanding of nervous system dysfunction and disease.
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Affiliation(s)
- Maria Ceprian
- Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain.
- Departamento de Bioquímica y Biología Molecular, CIBERNED, IRICYS. Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Daniel Fulton
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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10
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Zaidi A, Adewale M, McLean L, Ramlow P. The plasma membrane calcium pumps-The old and the new. Neurosci Lett 2019; 663:12-17. [PMID: 29452610 DOI: 10.1016/j.neulet.2017.09.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/29/2017] [Accepted: 09/30/2017] [Indexed: 12/27/2022]
Abstract
The plasma membrane Ca2+-ATPase (PMCA) pumps play a critical role in the maintenance of calcium (Ca2+) homeostasis, crucial for optimal neuronal function and cell survival. Loss of Ca2+ homeostasis is a key precursor in neuronal dysfunction associated with brain aging and in the pathogenesis of neurodegenerative disorders. In this article, we review evidence showing age-related changes in the PMCAs in synaptic plasma membranes (SPMs) and lipid raft microdomains isolated from rat brain. Both PMCA activity and protein levels decline progressively with increasing age. However, the loss of activity is disproportionate to the reduction of protein levels suggesting the presence of dysfunctional PMCA molecules in aged brain. PMCA activity is also diminished in post-mortem human brain samples from Alzheimer's disease and Parkinson's disease patients and in cell models of these neurodegenerative disorders. Experimental reduction of the PMCAs not only alter Ca2+ homeostasis but also have diverse effects on neurons such as reduced neuritic network, impaired release of neurotransmitter and increased susceptibility to stressful stimuli, particularly to agents that elevate intracellular Ca2+ [Ca2+]i. Loss of PMCA is likely to contribute to neuronal dysfunction observed in the aging brain and in the development of age-dependent neurodegenerative disorders. Therapeutic (pharmacological and/or non-pharmacological) approaches that can enhance PMCA activity and stabilize [Ca2+]i homeostasis may be capable of preventing, slowing, and/or reversing neuronal degeneration.
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Affiliation(s)
- Asma Zaidi
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA.
| | - Mercy Adewale
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA
| | - Lauren McLean
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA
| | - Paul Ramlow
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA
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11
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Hajieva P, Baeken MW, Moosmann B. The role of Plasma Membrane Calcium ATPases (PMCAs) in neurodegenerative disorders. Neurosci Lett 2019; 663:29-38. [PMID: 29452613 DOI: 10.1016/j.neulet.2017.09.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/11/2017] [Accepted: 09/14/2017] [Indexed: 01/27/2023]
Abstract
Selective degeneration of differentiated neurons in the brain is the unifying feature of neurodegenerative disorders such as Parkinson's disease (PD) or Alzheimer's disease (AD). A broad spectrum of evidence indicates that initially subtle, but temporally early calcium dysregulation may be central to the selective neuronal vulnerability observed in these slowly progressing, chronic disorders. Moreover, it has long been evident that excitotoxicity and its major toxic effector mechanism, neuronal calcium overload, play a decisive role in the propagation of secondary neuronal death after acute brain injury from trauma or ischemia. Under physiological conditions, neuronal calcium homeostasis is maintained by a fine-tuned interplay between calcium influx and releasing mechanisms (Ca2+-channels), and calcium efflux mechanisms (Ca2+-pumps and -exchangers). Central functional components of the calcium efflux machinery are the Plasma Membrane Calcium ATPases (PMCAs), which represent high-affinity calcium pumps responsible for the ATP-dependent removal of calcium out of the cytosol. Beyond a growing body of experimental evidence, it is their high expression level, their independence of secondary ions or membrane potential, their profound redox regulation and autoregulation, their postsynaptic localization in close proximity to the primary mediators of pathological calcium influx, i.e. NMDA receptors, as well as evolutionary considerations which all suggest a pivotal role of the PMCAs in the etiology of neurodegeneration and make them equally challenging and alluring candidates for drug development. This review aims to summarize the recent literature on the role of PMCAs in the pathogenesis of neurodegenerative disorders.
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Affiliation(s)
- Parvana Hajieva
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
| | - Marius W Baeken
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Bernd Moosmann
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
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12
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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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13
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Bano D, Ankarcrona M. Beyond the critical point: An overview of excitotoxicity, calcium overload and the downstream consequences. Neurosci Lett 2018; 663:79-85. [DOI: 10.1016/j.neulet.2017.08.048] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/16/2017] [Accepted: 08/18/2017] [Indexed: 01/11/2023]
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14
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Stafford N, Wilson C, Oceandy D, Neyses L, Cartwright EJ. The Plasma Membrane Calcium ATPases and Their Role as Major New Players in Human Disease. Physiol Rev 2017; 97:1089-1125. [PMID: 28566538 DOI: 10.1152/physrev.00028.2016] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 01/20/2017] [Accepted: 01/23/2017] [Indexed: 02/07/2023] Open
Abstract
The Ca2+ extrusion function of the four mammalian isoforms of the plasma membrane calcium ATPases (PMCAs) is well established. There is also ever-increasing detail known of their roles in global and local Ca2+ homeostasis and intracellular Ca2+ signaling in a wide variety of cell types and tissues. It is becoming clear that the spatiotemporal patterns of expression of the PMCAs and the fact that their abundances and relative expression levels vary from cell type to cell type both reflect and impact on their specific functions in these cells. Over recent years it has become increasingly apparent that these genes have potentially significant roles in human health and disease, with PMCAs1-4 being associated with cardiovascular diseases, deafness, autism, ataxia, adenoma, and malarial resistance. This review will bring together evidence of the variety of tissue-specific functions of PMCAs and will highlight the roles these genes play in regulating normal physiological functions and the considerable impact the genes have on human disease.
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Affiliation(s)
- Nicholas Stafford
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Claire Wilson
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Delvac Oceandy
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Ludwig Neyses
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Elizabeth J Cartwright
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
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15
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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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16
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Abstract
The PMCA is an ATP-driven Ca2+ pump critical for the maintenance of low cytosolic calcium. The PMCA has an important but paradoxical role in cell death and survival. The PMCA can be differentially regulated by caspase/calpain cleavage. Glycolytic ATP supply may be sufficient to fuel the PMCA during metabolic stress. The ATP sensitivity of the PMCA can be regulated by acidic phospholipids.
The plasma membrane Ca2+-ATPase (PMCA) is a ubiquitously expressed, ATP-driven Ca2+ pump that is critical for maintaining low resting cytosolic Ca2+ ([Ca2+]i) in all eukaryotic cells. Since cytotoxic Ca2+ overload has such a central role in cell death, the PMCA represents an essential “linchpin” for the delicate balance between cell survival and cell death. In general, impaired PMCA activity and reduced PMCA expression leads to cytotoxic Ca2+ overload and Ca2+ dependent cell death, both apoptosis and necrosis, whereas maintenance of PMCA activity or PMCA overexpression is generally accepted as being cytoprotective. However, the PMCA has a paradoxical role in cell death depending on the cell type and cellular context. The PMCA can be differentially regulated by Ca2+-dependent proteolysis, can be maintained by a localised glycolytic ATP supply, even in the face of global ATP depletion, and can be profoundly affected by the specific phospholipid environment that it sits within the membrane. The major focus of this review is to highlight some of the controversies surrounding the paradoxical role of the PMCA in cell death and survival, challenging the conventional view of ATP-dependent regulation of the PMCA and how this might influence cell fate.
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Affiliation(s)
- Jason I E Bruce
- Division of Molecular & Clinical Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, United Kingdom.
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17
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Abstract
The calcium signal is a powerful and multifaceted tool by which cells can achieve specific outcomes. Cellular machinery important in tumour progression is often driven or influenced by changes in calcium ions; in some cases this regulation occurs within spatially defined regions. Over the past decade there has been a deeper understanding of how calcium signalling is remodelled in some cancers and the consequences of calcium signalling on key events such as proliferation, invasion and sensitivity to cell death. Specific calcium signalling pathways have also now been identified as playing important roles in the establishment and maintenance of multidrug resistance and the tumour microenvironment.
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Affiliation(s)
- Gregory R Monteith
- The School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Brisbane, Queensland 4102, Australia
- Mater Research Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
- Translational Research Institute, Brisbane, Queensland 4102, Australia
| | - Natalia Prevarskaya
- Institut National de la Santé et de la Recherche Médicale U1003, Laboratoire de Physiologie Cellulaire, Equipe labellisée par la Ligue contre le cancer, and Universite de Lille 1, Villeneuve d'Ascq, F-59650, France
| | - Sarah J Roberts-Thomson
- The School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Brisbane, Queensland 4102, Australia
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18
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Calì T, Brini M, Carafoli E. Regulation of Cell Calcium and Role of Plasma Membrane Calcium ATPases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2017; 332:259-296. [PMID: 28526135 DOI: 10.1016/bs.ircmb.2017.01.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The plasma membrane Ca2+ ATPase (PMCA pump) is a member of the superfamily of P-type pumps. It has 10 transmembrane helices and 2 cytosolic loops, one of which contains the catalytic center. Its most distinctive feature is a C-terminal tail that contains most of the regulatory sites including that for calmodulin. The pump is also regulated by acidic phospholipids, kinases, a dimerization process, and numerous protein interactors. In mammals, four genes code for the four basic isoforms. Isoform complexity is increased by alternative splicing of primary transcripts. Pumps 2 and 3 are expressed preferentially in the nervous system. The pumps coexist with more powerful systems that clear Ca2+ from the bulk cytosol: their role is thus the regulation of Ca2+ in selected subplasma membrane microdomains, where a number of important Ca2+-dependent enzymes interact with them. Malfunctions of the pump lead to disease phenotypes that affect the nervous system preferentially.
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Affiliation(s)
- T Calì
- University of Padova, Padova, Italy
| | - M Brini
- University of Padova, Padova, Italy
| | - E Carafoli
- Venetian Institute of Molecular Medicine, Padova, Italy.
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19
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Ghosh B, Green MV, Krogh KA, Thayer SA. Interleukin-1β activates an Src family kinase to stimulate the plasma membrane Ca2+ pump in hippocampal neurons. J Neurophysiol 2016; 115:1875-85. [PMID: 26843596 PMCID: PMC4869483 DOI: 10.1152/jn.00541.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 01/23/2016] [Indexed: 01/09/2023] Open
Abstract
The plasma membrane Ca(2+) ATPase (PMCA) plays a major role in clearing Ca(2+) from the neuronal cytoplasm. The cytoplasmic Ca(2+) clearance rate affects neuronal excitability, synaptic plasticity, and neurotransmission. Here, we examined the modulation of PMCA activity by PTKs in hippocampal neurons. PMCA-mediated Ca(2+) clearance slowed in the presence of pyrazolopyrimidine 2, an inhibitor of Src family kinases (SFKs), and accelerated in the presence of C2-ceramide, an activator of PTKs. Ca(2+) clearance kinetics were attenuated in cells expressing a dominant-negative Src mutant, suggesting that the pump is tonically stimulated by a PTK. Tonic stimulation was reduced in hippocampal neurons expressing short hairpin (sh)RNA directed to mRNA for Yes. shRNA-mediated knockdown of PMCA isoform 1 (PMCA1) removed tonic stimulation of Ca(2+) clearance, indicating that the kinase stimulates PMCA1. IL-1β accelerated Ca(2+) clearance in a manner blocked by an IL-1β receptor antagonist or by an inhibitor of neutral sphingomyelinase, the enzyme that produces ceramide. Thus IL-1β activates an SFK to stimulate the plasma membrane Ca(2+) pump, decreasing the duration of Ca(2+) transients in hippocampal neurons.
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Affiliation(s)
- Biswarup Ghosh
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Matthew V Green
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Kelly A Krogh
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Stanley A Thayer
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota
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20
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Hoque A, Hossain MI, Ameen SS, Ang CS, Williamson N, Ng DCH, Chueh AC, Roulston C, Cheng HC. A beacon of hope in stroke therapy-Blockade of pathologically activated cellular events in excitotoxic neuronal death as potential neuroprotective strategies. Pharmacol Ther 2016; 160:159-79. [PMID: 26899498 DOI: 10.1016/j.pharmthera.2016.02.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Excitotoxicity, a pathological process caused by over-stimulation of ionotropic glutamate receptors, is a major cause of neuronal loss in acute and chronic neurological conditions such as ischaemic stroke, Alzheimer's and Huntington's diseases. Effective neuroprotective drugs to reduce excitotoxic neuronal loss in patients suffering from these neurological conditions are urgently needed. One avenue to achieve this goal is to clearly define the intracellular events mediating the neurotoxic signals originating from the over-stimulated glutamate receptors in neurons. In this review, we first focus on the key cellular events directing neuronal death but not involved in normal physiological processes in the neurotoxic signalling pathways. These events, referred to as pathologically activated events, are potential targets for the development of neuroprotectant therapeutics. Inhibitors blocking some of the known pathologically activated cellular events have been proven to be effective in reducing stroke-induced brain damage in animal models. Notable examples are inhibitors suppressing the ion channel activity of neurotoxic glutamate receptors and those disrupting interactions of specific cellular proteins occurring only in neurons undergoing excitotoxic cell death. Among them, Tat-NR2B9c and memantine are clinically effective in reducing brain damage caused by some acute and chronic neurological conditions. Our second focus is evaluation of the suitability of the other inhibitors for use as neuroprotective therapeutics. We also discuss the experimental approaches suitable for bridging our knowledge gap in our current understanding of the excitotoxic signalling mechanism in neurons and discovery of new pathologically activated cellular events as potential targets for neuroprotection.
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Affiliation(s)
- Ashfaqul Hoque
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - M Iqbal Hossain
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - S Sadia Ameen
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Ching-Seng Ang
- Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | | | - Dominic C H Ng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia; School of Biomedical Science, University of Queensland, St. Lucia, QLD, Australia
| | - Anderly C Chueh
- ACRF Chemical Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Carli Roulston
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Heung-Chin Cheng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia.
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21
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Wu Q, Guo D, Du Y, Liu D, Wang D, Bi H. UVB irradiation enhances TiO2 nanoparticle-induced disruption of calcium homeostasis in human lens epithelial cells. Photochem Photobiol 2014; 90:1324-31. [PMID: 25059545 DOI: 10.1111/php.12322] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/21/2014] [Indexed: 01/27/2023]
Abstract
Currently, titanium dioxide nanoparticles (TiO2 NPs) have been widely used in various applications including cosmetics, food additives and biomedicine. However, there are few reports available using TiO2 NPs to treat ocular diseases. Posterior capsular opacification (PCO) is the most frequent complication after cataract surgery, which is induced by the proliferation and migration of lens epithelial cells. Thus, inhibiting the proliferation of lens epithelial cells will efficiently reduce the occurrence of PCO. In this study, we investigated the effects of TiO2 NPs on HLE B-3 cells with or without ultraviolet B (UVB) irradiation in vitro. We found that TiO2 NPs can inhibit HLE B-3 cell growth, cause the elevation of intracellular [Ca(2+)], produce excessive reactive oxygen species (ROS), further reduce Ca(2+)-ATPase activity and decrease the expression of plasma membrane calcium ATPase 1 (PMCA1), finally disrupt the intracellular calcium homeostasis and induce cell damage. Importantly, UVB irradiation can apparently enhance these effects on HLE B-3 cells in the presence of TiO2 NPs. Taken together, the generation of excessive ROS and the disruption of intracellular calcium homeostasis may be both involved in TiO2 nanoparticle-induced HLE B-3 cell damage under UVB irradiation.
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Affiliation(s)
- Qiuxin Wu
- Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China; The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
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22
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Fairless R, Williams SK, Diem R. Dysfunction of neuronal calcium signalling in neuroinflammation and neurodegeneration. Cell Tissue Res 2013; 357:455-62. [PMID: 24326615 DOI: 10.1007/s00441-013-1758-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/31/2013] [Indexed: 02/07/2023]
Abstract
Neurodegeneration has been increasingly recognised as the leading structural correlate of disability progression in autoimmune diseases such as multiple sclerosis. Since calcium signalling is known to regulate the development of degenerative processes in many cell types, it is believed to play significant roles in mediating neurodegeneration. Because of its function as a major juncture linking various insults and injuries associated with inflammatory attack on neuronal cell bodies and axons, it provides potential for the development of neuroprotective strategies. This is of great significance because of the lack of neuroprotective agents presently available to supplement the current array of immunomodulatory treatments. In this review, we summarise the role that various calcium channels and pumps have been shown to play in the development of neurodegeneration under inflammatory autoimmune conditions. The identification of suitable targets might also provide insights into applications in non-inflammatory neurodegenerative diseases.
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Affiliation(s)
- Richard Fairless
- Department of Neuro-oncology, University Clinic Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
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23
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Caldeira MV, Salazar IL, Curcio M, Canzoniero LMT, Duarte CB. Role of the ubiquitin-proteasome system in brain ischemia: friend or foe? Prog Neurobiol 2013; 112:50-69. [PMID: 24157661 DOI: 10.1016/j.pneurobio.2013.10.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/08/2013] [Accepted: 10/15/2013] [Indexed: 11/26/2022]
Abstract
The ubiquitin-proteasome system (UPS) is a catalytic machinery that targets numerous cellular proteins for degradation, thus being essential to control a wide range of basic cellular processes and cell survival. Degradation of intracellular proteins via the UPS is a tightly regulated process initiated by tagging a target protein with a specific ubiquitin chain. Neurons are particularly vulnerable to any change in protein composition, and therefore the UPS is a key regulator of neuronal physiology. Alterations in UPS activity may induce pathological responses, ultimately leading to neuronal cell death. Brain ischemia triggers a complex series of biochemical and molecular mechanisms, such as an inflammatory response, an exacerbated production of misfolded and oxidized proteins, due to oxidative stress, and the breakdown of cellular integrity mainly mediated by excitotoxic glutamatergic signaling. Brain ischemia also damages protein degradation pathways which, together with the overproduction of damaged proteins and consequent upregulation of ubiquitin-conjugated proteins, contribute to the accumulation of ubiquitin-containing proteinaceous deposits. Despite recent advances, the factors leading to deposition of such aggregates after cerebral ischemic injury remain poorly understood. This review discusses the current knowledge on the role of the UPS in brain function and the molecular mechanisms contributing to UPS dysfunction in brain ischemia with consequent accumulation of ubiquitin-containing proteins. Chemical inhibitors of the proteasome and small molecule inhibitors of deubiquitinating enzymes, which promote the degradation of proteins by the proteasome, were both shown to provide neuroprotection in brain ischemia, and this apparent contradiction is also discussed in this review.
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Affiliation(s)
- Margarida V Caldeira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Ivan L Salazar
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Portugal
| | - Michele Curcio
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Science and Technology, University of Sannio, Benevento, Italy
| | | | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.
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24
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Wang D, Guo D, Bi H, Wu Q, Tian Q, Du Y. Zinc oxide nanoparticles inhibit Ca2+-ATPase expression in human lens epithelial cells under UVB irradiation. Toxicol In Vitro 2013; 27:2117-26. [PMID: 24060544 DOI: 10.1016/j.tiv.2013.09.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 08/07/2013] [Accepted: 09/12/2013] [Indexed: 10/26/2022]
Abstract
Epidemiological and experimental studies have revealed that lens epithelial cells exposed to ultraviolet B (UVB) light could be induced apoptosis, and lens epithelial cell apoptosis can initiate cataractogenesis. Posterior capsular opacification (PCO), the most frequent complication after cataract surgery, is induced by the proliferation, differentiation, migration of lens epithelial cells. Thus, inhibiting the proliferation of lens epithelial cells could reduce the occurrence of PCO. It is reported that zinc oxide (ZnO) nanoparticles have great potential for the application of biomedical field including cancer treatment. In the present study, we investigated the cytotoxic effect of ZnO nanoparticles on human lens epithelial cell (HLEC) viability. In addition, changes in cell nuclei, apoptosis, reactive oxygen species and intracellular calcium ion levels were also investigated after cells treated with ZnO nanoparticles in the presence and absence of UVB irradiation. Meanwhile, the expression of plasma membrane calcium ATPase 1 (PMCA1) was also determined at gene and protein levels. The results indicate that ZnO nanoparticles and UVB irradiation have synergistic inhibitory effect on HLEC proliferation in a concentration-dependent manner. ZnO nanoparticles can increase the intracellular calcium ion level, disrupt the intracellular calcium homeostasis, and decrease the expression level of PMCA1. UVB irradiation can strengthen the effect of reduced expression of PMCA1, suggesting that both UVB irradiation and ZnO nanoparticles could exert inhibitory effect on HLECs via calcium-mediated signaling pathway. ZnO nanoparticles have great potential for the treatment of PCO under UVB irradiation.
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Affiliation(s)
- Daoguang Wang
- Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, No. 48#, Yingxiongshan Road, Jinan 250002, China
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25
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Páramo B, Montiel T, Hernández-Espinosa DR, Rivera-Martínez M, Morán J, Massieu L. Calpain activation induced by glucose deprivation is mediated by oxidative stress and contributes to neuronal damage. Int J Biochem Cell Biol 2013; 45:2596-604. [PMID: 23994487 DOI: 10.1016/j.biocel.2013.08.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 07/30/2013] [Accepted: 08/16/2013] [Indexed: 12/16/2022]
Abstract
The mechanisms leading to neuronal death during glucose deprivation have not been fully elucidated, but a role of oxidative stress has been suggested. In the present study we have investigated whether the production of reactive oxygen species during glucose deprivation, contributes to the activation of calpain, a calcium-dependent protease involved in neuronal injury associated with brain ischemia and cerebral trauma. We have observed a rapid activation of calpain, as monitored by the cleavage of the cytoskeletal protein α-spectrin, after glucose withdrawal, which is reduced by inhibitors of xanthine oxidase, phospholipase A2 and NADPH oxidase. Results suggest that phospholipase A2 and NADPH oxidase contribute to the early activation of calpain after glucose deprivation. In particular NOX2, a member of the NADPH oxidase family is involved, since reduced stimulation of calpain activity is observed after glucose deprivation in hippocampal slices from transgenic mice lacking a functional NOX2. We observed an additive effect of the inhibitors of xanthine oxidase and phospholipase A2 on both ROS production and calpain activity, suggesting a synergistic action of these two enzymes. The present results provide new evidence showing that reactive oxygen species stimulate calpain activation during glucose deprivation and that this mechanism is involved in neuronal death.
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Affiliation(s)
- Blanca Páramo
- Departamento de Neuropatología Molecular, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, D.F. CP 04510, Mexico.
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26
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Heo M, Kim E. Beneficial effects of antecedent exercise training on limb motor function and calpain expression in a rat model of stroke. J Phys Ther Sci 2013; 25:943-6. [PMID: 24259890 PMCID: PMC3820215 DOI: 10.1589/jpts.25.943] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 03/28/2013] [Indexed: 01/11/2023] Open
Abstract
[Purpose] In the present study, we investigated the effects of antecedent exercise on functional recovery and calpain protein expression following focal cerebral ischemia injury. [Subjects and Methods] The rat middle cerebral artery occlusion model was employed. Adult male Sprague-Dawley rats were randomly divided into 4 groups. Group I comprised untreated normal rats (n=10); Group II comprised untreated rats with focal cerebral ischemia (n=10); Group III comprised rats that performed treadmill exercise (20 m/min) training after focal cerebral ischemia (n=10); and Group IV comprised rats that performed antecedent treadmill exercise (20 m/min) training before focal cerebral ischemia (n=10). At different time points (1, 7, 14, and 21 days), limb placement test score and the levels of calpain protein in the hippocampus were examined. [Results] In the antecedent exercise group, improvements in the motor behavior index (limb placement test) were observed and hippocampal calpain protein levels were decreased. [Conclusion] These results indicated that antecedent treadmill exercise prior to focal cerebral ischemia exerted neuroprotective effects against ischemic brain injury by improving motor performance and decreasing the levels of calpain expression. Furthermore, these results suggest that antecedent treadmill exercise of an appropriate intensity is critical for post-stroke rehabilitation.
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Affiliation(s)
- Myoung Heo
- Department of Occupational Therapy, Gwangju University
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27
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Antalffy G, Pászty K, Varga K, Hegedűs L, Enyedi Á, Padányi R. A C-terminal di-leucine motif controls plasma membrane expression of PMCA4b. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2561-2572. [PMID: 23830917 DOI: 10.1016/j.bbamcr.2013.06.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 06/18/2013] [Accepted: 06/24/2013] [Indexed: 01/17/2023]
Abstract
Recent evidences show that the localization of different plasma membrane Ca(2+) ATPases (PMCAs) is regulated in various complex, cell type-specific ways. Here we show that in low-density epithelial and endothelial cells PMCA4b localized mostly in intracellular compartments and its plasma membrane localization was enhanced upon increasing density of cells. In good correlation with the enhanced plasma membrane localization a significantly more efficient Ca(2+) clearance was observed in confluent versus non-confluent HeLa cell cultures expressing mCherry-PMCA4b. We analyzed the subcellular localization and function of various C-terminally truncated PMCA4b variants and found that a truncated mutant PMCA4b-ct24 was mostly intracellular while another mutant, PMCA4b-ct48, localized more to the plasma membrane, indicating that a protein sequence corresponding to amino acid residues 1158-1181 contained a signal responsible for the intracellular retention of PMCA4b in non-confluent cultures. Alteration of three leucines to alanines at positions 1167-1169 resulted in enhanced cell surface expression and an appropriate Ca(2+) transport activity of both wild type and truncated pumps, suggesting that the di-leucine-like motif (1167)LLL was crucial in targeting PMCA4b. Furthermore, upon loss of cell-cell contact by extracellular Ca(2+) removal, the wild-type pump was translocated to the early endosomal compartment. Targeting PMCA4b to early endosomes was diminished by the L(1167-69)A mutation, and the mutant pump accumulated in long tubular cytosolic structures. In summary, we report a di-leucine-like internalization signal at the C-tail of PMCA4b and suggest an internalization-mediated loss of function of the pump upon low degree of cell-cell contact.
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Affiliation(s)
- Géza Antalffy
- Molecular Biophysics Research Group of the Hungarian Academy of Sciences and Department of Biophysics, Semmelweis University, Budapest, Hungary
| | - Katalin Pászty
- Molecular Biophysics Research Group of the Hungarian Academy of Sciences and Department of Biophysics, Semmelweis University, Budapest, Hungary
| | - Karolina Varga
- Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Luca Hegedűs
- Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ágnes Enyedi
- Hungarian National Blood Transfusion Service, Budapest, Hungary; Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Rita Padányi
- Hungarian National Blood Transfusion Service, Budapest, Hungary.
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28
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Cheng G, Kong RH, Zhang LM, Zhang JN. Mitochondria in traumatic brain injury and mitochondrial-targeted multipotential therapeutic strategies. Br J Pharmacol 2013; 167:699-719. [PMID: 23003569 DOI: 10.1111/j.1476-5381.2012.02025.x] [Citation(s) in RCA: 231] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Traumatic brain injury (TBI) is a major health and socioeconomic problem throughout the world. It is a complicated pathological process that consists of primary insults and a secondary insult characterized by a set of biochemical cascades. The imbalance between a higher energy demand for repair of cell damage and decreased energy production led by mitochondrial dysfunction aggravates cell damage. At the cellular level, the main cause of the secondary deleterious cascades is cell damage that is centred in the mitochondria. Excitotoxicity, Ca(2+) overload, reactive oxygen species (ROS), Bcl-2 family, caspases and apoptosis inducing factor (AIF) are the main participants in mitochondria-centred cell damage following TBI. Some preclinical and clinical results of mitochondria-targeted therapy show promise. Mitochondria- targeted multipotential therapeutic strategies offer new hope for the successful treatment of TBI and other acute brain injuries.
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Affiliation(s)
- Gang Cheng
- Neurosurgical Department, PLA Navy General Hospital, Beijing, China
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29
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Puskarjov M, Ahmad F, Kaila K, Blaesse P. Activity-dependent cleavage of the K-Cl cotransporter KCC2 mediated by calcium-activated protease calpain. J Neurosci 2012; 32:11356-64. [PMID: 22895718 PMCID: PMC6621186 DOI: 10.1523/jneurosci.6265-11.2012] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 06/29/2012] [Accepted: 07/03/2012] [Indexed: 11/21/2022] Open
Abstract
The K-Cl cotransporter KCC2 plays a crucial role in neuronal chloride regulation. In mature central neurons, KCC2 is responsible for the low intracellular Cl(-) concentration ([Cl(-)](i)) that forms the basis for hyperpolarizing GABA(A) receptor-mediated responses. Fast changes in KCC2 function and expression have been observed under various physiological and pathophysiological conditions. Here, we show that the application of protein synthesis inhibitors cycloheximide and emetine to acute rat hippocampal slices have no effect on total KCC2 protein level and K-Cl cotransporter function. Furthermore, blocking constitutive lysosomal degradation with leupeptin did not induce significant changes in KCC2 protein levels. These findings indicate a low basal turnover rate of the total KCC2 protein pool. In the presence of the glutamate receptor agonist NMDA, the total KCC2 protein level decreased to about 30% within 4 h, and this effect was blocked by calpeptin and MDL-28170, inhibitors of the calcium-activated protease calpain. Interictal-like activity induced by incubation of hippocampal slices in an Mg(2+)-free solution led to a fast reduction in KCC2-mediated Cl(-) transport efficacy in CA1 pyramidal neurons, which was paralleled by a decrease in both total and plasmalemmal KCC2 protein. These effects were blocked by the calpain inhibitor MDL-28170. Taken together, these findings show that calpain activation leads to cleavage of KCC2, thereby modulating GABAergic signaling.
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Affiliation(s)
- Martin Puskarjov
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
| | - Faraz Ahmad
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
| | - Kai Kaila
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
| | - Peter Blaesse
- Department of Biosciences and Neuroscience Center, University of Helsinki, FI-00014 Helsinki, Finland and
- Institute of Physiology I, Westfälische Wilhelms-University Münster, D-48149 Münster, Germany
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30
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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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31
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Salm EJ, Thayer SA. Homer proteins accelerate Ca2+ clearance mediated by the plasma membrane Ca2+ pump in hippocampal neurons. Biochem Biophys Res Commun 2012; 424:76-81. [PMID: 22732411 DOI: 10.1016/j.bbrc.2012.06.069] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 06/15/2012] [Indexed: 10/28/2022]
Abstract
The plasma membrane Ca(2+) ATPase (PMCA) is responsible for maintaining basal intracellular Ca(2+) concentration ([Ca(2+)](i)) and returning small increases in [Ca(2+)](i) back to resting levels. The carboxyl terminus of some PMCA splice variants bind Homer proteins; how binding affects PMCA function is unknown. Here, we examined the effects of altered expression of Homer proteins on PMCA-mediated Ca(2+) clearance from rat hippocampal neurons in culture. The kinetics of PMCA-mediated recovery from the [Ca(2+)](i) increase evoked by a brief train of action potentials was determined in the soma of single neurons using indo-1-based photometry. Exogenous expression of Homer 1a, Homer 1c or Homer 2a did not affect PMCA function. However, shRNA mediated knockdown of Homer 1 slowed PMCA mediated Ca(2+) clearance by 28% relative to cells expressing non-silencing shRNA. The slowed recovery rate in cells expressing Homer 1 shRNA was reversed by expression of a short Homer 2 truncation mutant. These results indicate that constitutively expressed Homer proteins tonically stimulate PMCA function in hippocampal neurons. We propose a model in which binding of short or long Homer proteins to the carboxyl terminus of the PMCA stimulates Ca(2+) clearance rate. PMCA-mediated Ca(2+) clearance may be stimulated following incorporation of the pump into Homer organized signaling domains and following induction of the Homer 1a immediate early gene.
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Affiliation(s)
- Elizabeth J Salm
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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32
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Calcium microdomains at the immunological synapse: how ORAI channels, mitochondria and calcium pumps generate local calcium signals for efficient T-cell activation. EMBO J 2011; 30:3895-912. [PMID: 21847095 DOI: 10.1038/emboj.2011.289] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 07/19/2011] [Indexed: 12/24/2022] Open
Abstract
Cell polarization enables restriction of signalling into microdomains. Polarization of lymphocytes following formation of a mature immunological synapse (IS) is essential for calcium-dependent T-cell activation. Here, we analyse calcium microdomains at the IS with total internal reflection fluorescence microscopy. We find that the subplasmalemmal calcium signal following IS formation is sufficiently low to prevent calcium-dependent inactivation of ORAI channels. This is achieved by localizing mitochondria close to ORAI channels. Furthermore, we find that plasma membrane calcium ATPases (PMCAs) are re-distributed into areas beneath mitochondria, which prevented PMCA up-modulation and decreased calcium export locally. This nano-scale distribution-only induced following IS formation-maximizes the efficiency of calcium influx through ORAI channels while it decreases calcium clearance by PMCA, resulting in a more sustained NFAT activity and subsequent activation of T cells.
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Gouriou Y, Demaurex N, Bijlenga P, De Marchi U. Mitochondrial calcium handling during ischemia-induced cell death in neurons. Biochimie 2011; 93:2060-7. [PMID: 21846486 DOI: 10.1016/j.biochi.2011.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 08/03/2011] [Indexed: 12/18/2022]
Abstract
Mitochondria sense and shape cytosolic Ca(2+) signals by taking up and subsequently releasing Ca(2+) ions during physiological and pathological Ca(2+) elevations. Sustained elevations in the mitochondrial matrix Ca(2+) concentration are increasingly recognized as a defining feature of the intracellular cascade of lethal events that occur in neurons during cerebral ischemia. Here, we review the recently identified transport proteins that mediate the fluxes of Ca(2+) across mitochondria and discuss the implication of the permeability transition pore in decoding the abnormally sustained mitochondrial Ca(2+) elevations that occur during cerebral ischemia.
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Affiliation(s)
- Yves Gouriou
- Department of Cell Physiology and Metabolism, University of Geneva, rue Michel-Servet 1, Genève, Switzerland
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Colón-Sáez JO, Yakel JL. The α7 nicotinic acetylcholine receptor function in hippocampal neurons is regulated by the lipid composition of the plasma membrane. J Physiol 2011; 589:3163-74. [PMID: 21540349 DOI: 10.1113/jphysiol.2011.209494] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The α7 nicotinic acetylcholine receptors (nAChRs) play an important role in cellular events such as neurotransmitter release, second messenger cascades, cell survival and apoptosis. In addition, they are a therapeutic target for the treatment of neurological disorders such as Alzheimer's disease and schizophrenia, and drugs that potentiate α7 nAChRs through the regulation of desensitization are currently being developed. Recently, these channels were found to be localized into lipid rafts. Here we show that the disruption of lipid rafts in rat primary hippocampal neurons, through cholesterol-scavenging drugs (methyl-β-cyclodextrin) and the enzymatic breakdown of sphingomyelin (sphingomyelinase), results in significant changes in the desensitization kinetics of native and expressed α7 nAChRs. These effects can be prevented by cotreatment with cholesterol and sphingomyelin, and can be mimicked by treatment with cholesterol and sphingomyelin synthesis inhibitors (mevastatin and myriocin, respectively), suggesting that the effects on desensitization kinetics are indeed due to changes in the levels of cholesterol and sphingomyelin in the plasma membrane. These data provide new insights into themechanism of desensitization of α7 nAChRs by providing evidence that the lipid composition of the plasma membrane can modulate the activity of the α7 nAChRs.
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Affiliation(s)
- José O Colón-Sáez
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
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35
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Bravo-Martínez J, Delgado-Coello B, García DE, Mas-Oliva J. Analysis of plasma membrane Ca2+-ATPase gene expression during epileptogenesis employing single hippocampal CA1 neurons. Exp Biol Med (Maywood) 2011; 236:409-17. [PMID: 21444370 DOI: 10.1258/ebm.2011.010342] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Disruption of calcium homeostasis in epileptic cells is characterized by both short- and long-term perturbations of Ca(2+) buffering systems. Along with the Na(+)/Ca(2+) exchanger, the plasma membrane Ca(2+)-ATPase (PMCA) plays an important role in excitable cells. The involvement of PMCAs in epileptogenesis has primarily been studied in brief intervals after various stimuli; however, the specific contribution of this molecule to epileptogenesis is not yet fully understood. Our aim has been to investigate whether PMCA expression in the chronic stages of epilepsy is altered. Through an interdisciplinary approach, involving whole-cell recordings and real-time reverse transcriptase-polymerase chain reaction, we have shown that epileptic neurons in our preparation consistently show changes in electrical properties during the period of chronic epilepsy. These changes included increased spike frequency, altered resting membrane potential and changes in passive membrane properties. Following these observations, which indicate an altered excitability in the epileptic cells studied, PMCA mRNA transcripts were studied. It was found that while PMCA1 transcripts are significantly increased one month following the pilocarpine epileptogenic stimulus, PMCA3, an isoform important in excitable tissues, was significantly, decreased. These findings suggest that, in the long-term, a slow PMCA (PMCA1) plays a role in the reestablishment of a new calcium homeostasis attained by epileptic cells. Overall, this phenomenon points out the fact that in seizure disorders, changes that take place in the balance of the different molecules and their isoforms in charge of maintaining neuronal calcium homeostasis, are fundamental in the survival of affected cells.
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Affiliation(s)
- Jorge Bravo-Martínez
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, México, DF México
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36
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Momeni HR. Role of calpain in apoptosis. CELL JOURNAL 2011; 13:65-72. [PMID: 23507938 PMCID: PMC3584455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 01/25/2011] [Indexed: 11/28/2022]
Abstract
Apoptosis, a form of programmed cell death that occurs under physiological as well as pathological conditions, is characterized by morphological and biochemical features. While the importance of caspases in apoptosis is established, several noncaspase proteases (Ca(2+)-dependent proteases) such as calpain may play a role in the execution of apoptosis. The calpain family consists of two major isoforms, calpain I and calpain II which require µM and mM Ca(2+) concentrations to initiate their activity. An increase in intracellular Ca(2+) level is thought to trigger a cascade of biochemical processes including calpain activation. Once activated, calpains degrade membrane, cytoplasmic and nuclear substrates, leading to the breakdown of cellular architecture and finally apoptosis. The activation of calpain has been implicated in neuronal apoptosis following spinal cord injuries and neurodegenerative diseases. This review focuses on calpain with an emphasis on its key role in the proteolysis of cellular protein substrates following apoptosis.
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Affiliation(s)
- Hamid Reza Momeni
- * Corresponding Address: Biology DepartmentFaculty of ScienceArak UniversityArak38156-8-8349 Iran
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37
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McCormack TJ, Melis C, Colón J, Gay EA, Mike A, Karoly R, Lamb PW, Molteni C, Yakel JL. Rapid desensitization of the rat α7 nAChR is facilitated by the presence of a proline residue in the outer β-sheet. J Physiol 2010; 588:4415-29. [PMID: 20837638 PMCID: PMC3008848 DOI: 10.1113/jphysiol.2010.195495] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 09/09/2010] [Indexed: 11/08/2022] Open
Abstract
The rat α7 nicotinic acetylcholine receptor (nAChR) has a proline residue near the middle of the β9 strand. The replacement of this proline residue at position 180 (P180) by either threonine (α7-P180T) or serine (α7-P180S) slowed the onset of desensitization dramatically, with half-times of ~930 and 700 ms, respectively, compared to 90 ms for the wild-type receptor. To investigate the importance of the hydroxyl group on the position 180 side-chains, the mutant receptors α7-P180Y and α7-P180F were studied and showed half-times of desensitization of 650 and 160 ms, respectively. While a position 180 side-chain OH group may contribute to the slow desensitization rates, α7-P180S and α7-P180V resulted in receptors with similar desensitization rates, suggesting that increased backbone to backbone H bonding expected in the absence of proline at position 180 would likely exert a great effect on desensitization. Single channel recordings indicated that for the α7-P180T receptor there was a significantly reduced closed time without any change in single channel conductance (as compared to wild-type). Kinetic simulations indicated that all changes observed for the mutant channel behaviour were reproduced by decreasing the rate of desensitization, and increasing the microscopic affinity to resting receptors. Molecular dynamics (MD) simulations on a homology model were used to provide insight into likely H bond interactions within the outer β-sheet that occur when the P180 residue is mutated. All mutations analysed increased about twofold the predicted number of H bonds between the residue at position 180 and the backbone of the β10 strand. Moreover, the α7-P180T and α7-P180S mutations also formed some intrastrand H bonds along the β9 strand, although H bonding of the OH groups of the threonine or serine side-chains was predicted to be infrequent. Our results indicate that rapid desensitization of the wild-type rat α7 nAChR is facilitated by the presence of the proline residue within the β9 strand.
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Affiliation(s)
- Thomas J McCormack
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
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38
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Zaidi A. Plasma membrane Ca 2+-ATPases: Targets of oxidative stress in brain aging and neurodegeneration. World J Biol Chem 2010; 1:271-80. [PMID: 21537484 PMCID: PMC3083975 DOI: 10.4331/wjbc.v1.i9.271] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 08/20/2010] [Accepted: 08/27/2010] [Indexed: 02/05/2023] Open
Abstract
The plasma membrane Ca2+-ATPase (PMCA) pumps play an important role in the maintenance of precise levels of intracellular Ca2+ [Ca2+]i, essential to the functioning of neurons. In this article, we review evidence showing age-related changes of the PMCAs in synaptic plasma membranes (SPMs). PMCA activity and protein levels in SPMs diminish progressively with increasing age. The PMCAs are very sensitive to oxidative stress and undergo functional and structural changes when exposed to oxidants of physiological relevance. The major signatures of oxidative modification in the PMCAs are rapid inactivation, conformational changes, aggregation, internalization from the plasma membrane and proteolytic degradation. PMCA proteolysis appears to be mediated by both calpains and caspases. The predominance of one proteolytic pathway vs the other, the ensuing pattern of PMCA degradation and its consequence on pump activity depends largely on the type of insult, its intensity and duration. Experimental reduction of PMCA expression not only alters the dynamics of cellular Ca2+ handling but also has a myriad of downstream consequences on various aspects of cell function, indicating a broad role of these pumps. Age- and oxidation-related down-regulation of the PMCAs may play an important role in compromised neuronal function in the aging brain and its several-fold increased susceptibility to neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and stroke. Therapeutic approaches that protect the PMCAs and stabilize [Ca2+]i homeostasis may be capable of slowing and/or preventing neuronal degeneration. The PMCAs are therefore emerging as a new class of drug targets for therapeutic interventions in various chronic degenerative disorders.
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Affiliation(s)
- Asma Zaidi
- Asma Zaidi, Department of Biochemistry, Kansas City University of Medicine and Biosciences, Kansas City, MO 64106, United States
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39
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Bruce JI. Plasma membrane calcium pump regulation by metabolic stress. World J Biol Chem 2010; 1:221-8. [PMID: 21537477 PMCID: PMC3083969 DOI: 10.4331/wjbc.v1.i7.221] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 06/30/2010] [Accepted: 07/07/2010] [Indexed: 02/05/2023] Open
Abstract
The plasma membrane Ca2+-ATPase (PMCA) is an ATP-driven pump that is critical for the maintenance of low resting [Ca2+]i in all eukaryotic cells. Metabolic stress, either due to inhibition of mitochondrial or glycolytic metabolism, has the capacity to cause ATP depletion and thus inhibit PMCA activity. This has potentially fatal consequences, particularly for non-excitable cells in which the PMCA is the major Ca2+ efflux pathway. This is because inhibition of the PMCA inevitably leads to cytosolic Ca2+ overload and the consequent cell death. However, the relationship between metabolic stress, ATP depletion and inhibition of the PMCA is not as simple as one would have originally predicted. There is increasing evidence that metabolic stress can lead to the inhibition of PMCA activity independent of ATP or prior to substantial ATP depletion. In particular, there is evidence that the PMCA has its own glycolytic ATP supply that can fuel the PMCA in the face of impaired mitochondrial function. Moreover, membrane phospholipids, mitochondrial membrane potential, caspase/calpain cleavage and oxidative stress have all been implicated in metabolic stress-induced inhibition of the PMCA. The major focus of this review is to challenge the conventional view of ATP-dependent regulation of the PMCA and bring together some of the alternative or additional mechanisms by which metabolic stress impairs PMCA activity resulting in cytosolic Ca2+ overload and cytotoxicity.
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Affiliation(s)
- Jason Ie Bruce
- Jason IE Bruce, Faculty of Life Sciences, The University of Manchester, Manchester M13 9NT, United Kingdom
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40
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Fakira AK, Elkabes S. Role of plasma membrane calcium ATPase 2 in spinal cord pathology. World J Biol Chem 2010; 1:103-8. [PMID: 21540996 PMCID: PMC3083954 DOI: 10.4331/wjbc.v1.i5.103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 05/11/2010] [Accepted: 05/18/2010] [Indexed: 02/05/2023] Open
Abstract
A number of studies have indicated that plasma membrane calcium ATPases (PMCAs) are expressed in the brain and spinal cord and could play important roles not only in the maintenance of cellular calcium homeostasis but also in the survival and function of central nervous system cells under pathological conditions. The different regional and cellular distributions of the various PMCA isoforms and splice variants in the nervous system and the diverse phenotypes of PMCA knockout mice support the notion that each isoform might play a distinct role. Especially in the spinal cord, the survival of neurons and, in particular, motor neurons could be dependent on PMCA2. This is indicated by the knockdown of PMCA2 in pure spinal cord neuronal cultures that leads to cell death via a decrease in collapsing response mediator protein 1 levels. Moreover, the progressive decline in the number of motor neurons in PMCA2-null mice and heterozygous mice further supports this notion. Therefore, the reported reduction in PMCA2 mRNA and protein levels in the inflamed spinal cord of mice affected by experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, and after spinal cord contusion injury, suggests that changes in PMCA2 expression could be a cause of neuronal pathology and death during inflammation and injury. Glutamate excitotoxicity mediated via kainate receptors has been implicated in the neuropathology of both EAE and spinal cord injury, and has been identified as a trigger that reduces PMCA2 levels in pure spinal cord neuronal cultures through degradation of the pump by calpain without affecting PMCA2 transcript levels. It remains to be determined which other stimuli modulate PMCA2 mRNA expression in the aforementioned pathological conditions of the spinal cord.
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Affiliation(s)
- Amanda Kathleen Fakira
- Amanda Kathleen Fakira, Stella Elkabes, Department of Neurology and Neuroscience, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 185 S. Orange Avenue, Newark, NJ 07003, United States
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41
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Kurnellas MP, Li H, Jain MR, Giraud SN, Nicot AB, Ratnayake A, Heary RF, Elkabes S. Reduced expression of plasma membrane calcium ATPase 2 and collapsin response mediator protein 1 promotes death of spinal cord neurons. Cell Death Differ 2010; 17:1501-10. [PMID: 20489728 DOI: 10.1038/cdd.2010.54] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The mechanisms underlying neuronal pathology and death in the spinal cord (SC) during inflammation remain elusive. We previously showed the important role of plasma membrane calcium ATPases (PMCAs) in the survival of SC neurons, in vitro. We also postulated that a decrease in PMCA2 expression could cause neuronal death during experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. The current studies were undertaken to define the specific contribution of PMCA2 to degeneration of SC neurons, the effectors downstream to PMCA2 mediating neuronal death and the triggers that reduce PMCA2 expression. We report that knockdown of PMCA2 in SC neurons decreases collapsin response mediator protein 1 (CRMP1) levels. This is followed by cell death. Silencing of CRMP1 expression also leads to neuronal loss. Kainic acid reduces both PMCA2 and CRMP1 levels and induces neuronal death. Administration of an alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA)/kainate receptor antagonist, at onset or peak of EAE, restores the decreased PMCA2 and CRMP1 levels to control values and ameliorates clinical deficits. Thus, our data link the reduction in PMCA2 expression with perturbations in the expression of CRMP1 and the ensuing death of SC neurons. This represents an additional mechanism underlying AMPA/kainate receptor-mediated excitotoxicity with relevance to neurodegeneration in EAE.
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Affiliation(s)
- M P Kurnellas
- Department of Neurology and Neuroscience, New Jersey Medical School-UMDNJ, Newark, 07103, USA
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42
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Abstract
At hippocampal excitatory synapses, endocannabinoids (eCBs) mediate two forms of retrograde synaptic inhibition that are induced by postsynaptic depolarization or activation of metabotropic glutamate receptors (mGluRs). The homer family of molecular scaffolds provides spatial organization to regulate postsynaptic signaling cascades, including those activated by mGluRs. Expression of the homer 1a (H1a) immediate-early gene produces a short homer protein that lacks the domain required for homer oligomerization, enabling it to uncouple homer assemblies. Here, we report that H1a differentially modulates two forms of eCB-mediated synaptic plasticity, depolarization-induced suppression of excitation (DSE) and metabotropic suppression of excitation (MSE). EPSCs were recorded from cultured hippocampal neurons and DSE evoked by a 15 s depolarization to 0 mV and MSE evoked by a type I mGluR agonist. Expression of H1a enhanced DSE and inhibited MSE at the same synapse. Many physiologically important stimuli initiate H1a expression including brain-derived neurotrophic factor (BDNF). Treating hippocampal cultures with BDNF increased transcription of H1a and uncoupled homer 1c-GFP (green fluorescent protein) clusters. BDNF treatment blocked MSE and enhanced DSE. Thus, physiological changes in H1a expression gate the induction pathway for eCB-mediated synaptic plasticity by uncoupling mGluR from eCB production.
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43
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Brustovetsky T, Bolshakov A, Brustovetsky N. Calpain activation and Na+/Ca2+ exchanger degradation occur downstream of calcium deregulation in hippocampal neurons exposed to excitotoxic glutamate. J Neurosci Res 2010; 88:1317-28. [PMID: 19937813 PMCID: PMC2830319 DOI: 10.1002/jnr.22295] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Delayed calcium deregulation (DCD) plays an essential role in glutamate excitotoxicity, a major detrimental factor in stroke, traumatic brain injury, and various neurodegenerations. In the present study, we examined the role of calpain activation and Na(+)/Ca(2+) exchanger (NCX) degradation in DCD and excitotoxic cell death in cultured hippocampal neurons. Exposure of neurons to glutamate caused DCD accompanied by secondary mitochondrial depolarization. Activation of calpain was evidenced by detecting NCX isoform 3 (NCX3) degradation products. Degradation of NCX isoform 1 (NCX1) was below the detection limit of Western blotting. Degradation of NCX3 was detected only after 1 hr of incubation with glutamate, whereas DCD occurred on average within 15 min after glutamate application. Calpeptin, an inhibitor of calpain, significantly attenuated NCX3 degradation but failed to inhibit DCD and excitotoxic neuronal death. Calpain inhibitors I, III, and VI also failed to influence DCD and glutamate-induced neuronal death. On the other hand, MK801, an inhibitor of the NMDA subtype of glutamate receptors, added shortly after the initial glutamate-induced jump in cytosolic Ca(2+), completely prevented DCD and activation of calpain and strongly protected neurons against excitotoxicity. Taken together, our results suggest that, in glutamate-treated hippocampal neurons, the initial increase in cytosolic Ca(2+) that precedes DCD is insufficient for sustained calpain activation, which most likely occurs downstream of DCD.
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Affiliation(s)
- Tatiana Brustovetsky
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Alexey Bolshakov
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Nickolay Brustovetsky
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Abstract
Chronic changes in electrical excitability profoundly affect synaptic transmission throughout the lifetime of a neuron. We have previously explored persistent presynaptic silencing, a form of synaptic depression at glutamate synapses produced by ongoing neuronal activity and by strong depolarization. Here we investigate the involvement of the ubiquitin-proteasome system (UPS) in the modulation of presynaptic function. We found that proteasome inhibition prevented the induction of persistent presynaptic silencing. Specifically, application of the proteasome inhibitor MG-132 (carbobenzoxy-L-leucyl-L-leucyl-L-leucinal) prevented decreases in the size of the readily releasable pool of vesicles and in the percentage of active synapses. Presynaptic silencing was accompanied by decreases in levels of the priming proteins Munc13-1 and Rim1. Importantly, overexpression of Rim1alpha prevented the induction of persistent presynaptic silencing. Furthermore, strong depolarization itself increased proteasome enzymatic activity measured in cell lysates. These results suggest that modulation of the UPS by electrical activity contributes to persistent presynaptic silencing by promoting the degradation of key presynaptic proteins.
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45
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Abstract
NMDA (N-methyl-D-aspartate) receptors are a subtype of ionotropic glutamate receptor with an important role in the physiology and pathophysiology of central neurons. Inappropriate levels of Ca(2+) influx through the NMDA receptor can contribute to neuronal loss in acute trauma such as ischaemia and traumatic brain injury, as well as certain neurodegenerative diseases such as Huntington's disease. However, normal physiological patterns of NMDA receptor activity can promote neuroprotection against both apoptotic and excitotoxic insults. As a result, NMDA receptor blockade can promote neuronal death outright or render neurons vulnerable to secondary trauma. Thus responses to NMDA receptor activity follow a classical hormetic dose-response curve: both too much and too little can be harmful. There is a growing knowledge of the molecular mechanisms underlying both the neuroprotective and neurodestructive effects of NMDA receptor activity, as well as the factors that determine whether an episode of NMDA receptor activity is harmful or beneficial. It is becoming apparent that oxidative stress plays a role in promoting neuronal death in response to both hyper- and hypo-activity of the NMDA receptor. Increased understanding in this field is leading to the discovery of new therapeutic targets and strategies for excitotoxic disorders, as well as a growing appreciation of the harmful consequences of NMDA receptor blockade.
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Affiliation(s)
- Giles E Hardingham
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
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Zaidi A, Fernandes D, Bean JL, Michaelis ML. Effects of paraquat-induced oxidative stress on the neuronal plasma membrane Ca(2+)-ATPase. Free Radic Biol Med 2009; 47:1507-14. [PMID: 19715754 PMCID: PMC2789485 DOI: 10.1016/j.freeradbiomed.2009.08.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 08/17/2009] [Accepted: 08/20/2009] [Indexed: 12/25/2022]
Abstract
Oxidative stress leads to the disruption of calcium homeostasis in brain neurons; however, the direct effects of oxidants on proteins that regulate intracellular calcium ([Ca(2+)](i)) are not known. The calmodulin (CaM)-stimulated plasma membrane Ca(2+)-ATPase (PMCA) plays a critical role in regulating [Ca(2+)](i). Our previous in vitro studies showed that PMCA present in brain synaptic membranes is readily inactivated by a variety of reactive oxygen species (ROS). The present studies were conducted to determine the vulnerability of PMCA to ROS generated in neurons as would probably occur in vivo. Primary cortical neurons were exposed to paraquat (PQ), a redox cycling agent that generates intracellular ROS. Low concentrations of PQ (5-10 microM) increased PMCA basal activity by two-fold but abolished its sensitivity to CaM. Higher concentrations (25-100 microM) inhibited both components of PMCA activity. Immunoblots showed the formation of high-molecular-weight PMCA aggregates. Additionally, PMCA showed evidence of proteolytic degradation. PMCA proteolysis was prevented by a calpain inhibitor, suggesting a role for calpain. Our findings suggest that PMCA is a sensitive target of oxidative stress in primary neurons. Inactivation of this Ca(2+) transporter under prolonged oxidative stress could alter neuronal Ca(2+) signaling.
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Affiliation(s)
- Asma Zaidi
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, KS 66045, USA.
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Gerencser AA, Mark KA, Hubbard AE, Divakaruni AS, Mehrabian Z, Nicholls DG, Polster BM. Real-time visualization of cytoplasmic calpain activation and calcium deregulation in acute glutamate excitotoxicity. J Neurochem 2009; 110:990-1004. [PMID: 19493161 DOI: 10.1111/j.1471-4159.2009.06194.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Although calpain (EC 3.4.22) protease activation was suggested to contribute to excitotoxic delayed calcium deregulation (DCD) via proteolysis of Na+/Ca2+ exchanger 3 (NCX3), cytoplasmic calpain activation in relation to DCD has never been visualized in real-time. We employed a calpain fluorescence resonance energy transfer substrate to simultaneously image calpain activation and calcium deregulation in live cortical neurons. A calpain inhibitor-sensitive decline in fluorescence resonance energy transfer was observed at 39 +/- 5 min after the occurrence of DCD in neurons exposed to continuous glutamate (100 microM). Inhibition of calpain by calpeptin did not delay the onset of DCD, recovery from DCD-like reversible calcium elevations, or cell death despite inhibiting alpha-spectrin processing by > 90%. NCXs reversed during glutamate exposure, the NCX antagonist KB-R7943 prolonged the time to DCD, and significant NCX3 cleavage following 90 min of glutamate exposure was not observed. Our findings suggest that robust calpain activation associated with acute glutamate toxicity occurs only after a sustained loss in calcium homeostasis. Processing of NCX3 or other calpain substrates is unlikely to be the primary cause of acute excitotoxicity in cortical neurons. However, a role for calpain as a contributing factor or in response to milder glutamate insults is not excluded.
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48
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Ferragamo MJ, Reinardy JL, Thayer SA. Ca2+-dependent, stimulus-specific modulation of the plasma membrane Ca2+ pump in hippocampal neurons. J Neurophysiol 2009; 101:2563-71. [PMID: 19244356 DOI: 10.1152/jn.90774.2008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The plasma membrane Ca(2+) ATPase (PMCA) plays a major role in restoring Ca(2+) to basal levels following transient elevation by neuronal activity. Here we examined the effects of various stimuli that increase [Ca(2+)](i) on PMCA-mediated Ca(2+) clearance from hippocampal neurons. We used indo-1-based microfluorimetry in the presence of cyclopiazonic acid to study the rate of PMCA-mediated recovery of Ca(2+) elevated by a brief train of action potentials. [Ca(2+)](i) recovery was described by an exponential decay and the time constant provided an index of PMCA-mediated Ca(2+) clearance. PMCA function was assessed before and for >or=60 min following a 10-min priming stimulus of either 100 microM N-methyl-d-aspartate (NMDA), 0.1 mM Mg(2+) (reduced extracellular Mg(2+) induces intense excitatory synaptic activity), 30 mM K(+), or control buffer. Recovery kinetics slowed progressively following priming with NMDA or 0.1 mM Mg(2+); in contrast, Ca(2+) clearance initially accelerated and then slowly returned to initial rates following priming with 30 mM K(+)-induced depolarization. Treatment with 10 muM calpeptin, an inhibitor of the Ca(2+) activated protease calpain, prevented the slowing of kinetics observed following treatment with NMDA but had no affect on the recovery kinetics of control cells. Calpeptin also blocked the rapid acceleration of Ca(2+) clearance following depolarization. In calpeptin-treated cells, 0.1 mM Mg(2+) induced a graded acceleration of Ca(2+) clearance. Thus in spite of producing comparable increases in [Ca(2+)](i), activation of NMDA receptors, depolarization-induced activation of voltage-gated Ca(2+) channels and excitatory synaptic activity each uniquely affected Ca(2+) clearance kinetics mediated by the PMCA.
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Affiliation(s)
- Michael J Ferragamo
- Department of Biology, Gustavus Adolphus College, Saint Peter, Minneapolis, MN, USA
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Behringer EJ, Vanterpool CK, Pearce WJ, Wilson SM, Buchholz JN. Advancing age alters the contribution of calcium release from smooth endoplasmic reticulum stores in superior cervical ganglion cells. J Gerontol A Biol Sci Med Sci 2009; 64:34-44. [PMID: 19196634 PMCID: PMC2673896 DOI: 10.1093/gerona/gln053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In superior cervical ganglion (SCG) neurons calcium-induced calcium release (CICR), mediated by ryanodine receptors (RyRs), contributes to stimulation-evoked intracellular calcium ([Ca2+]i) transients. Hypothesis: The contribution of CICR to electrical field stimulation (EFS)–evoked [Ca2+]i transients in SCG cells declines with senescence and may be partially recovered in the presence of caffeine. We measured EFS-evoked [Ca2+]i transients in isolated fura-2–loaded SCG cells from Fischer-344 rats aged 6, 12, and 24 months with either the RyR antagonist ryanodine to block the contribution of CICR to [Ca2+]i transients or caffeine to sensitize CICR to EFS. EFS-evoked [Ca2+]i transients increased from 6 to 12 months and declined at 24 months and ryanodine decreased [Ca2+]i transients in SCG cells from 6- and 12-month-old animals only. Caffeine significantly increased EFS-evoked [Ca2+]i transients in all age groups. These data suggest that CICR declines with senescence and residual CICR function may be reclaimed in senescent cells with caffeine.
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Affiliation(s)
- Erik J Behringer
- Department of Physiology and Pharmacology, Loma Linda University, CA 92354, USA
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Roloff AM, Thayer SA. Modulation of excitatory synaptic transmission by Delta 9-tetrahydrocannabinol switches from agonist to antagonist depending on firing rate. Mol Pharmacol 2008; 75:892-900. [PMID: 19118122 DOI: 10.1124/mol.108.051482] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Delta(9)-tetrahydrocannabinol (THC), the principal psychoactive ingredient in marijuana, acts as a partial agonist on presynaptic cannabinoid type 1 (CB1) receptors to inhibit neurotransmitter release. Here, we report that THC inhibits excitatory neurotransmission between cultured rat hippocampal neurons in a manner highly sensitive to stimulus rate. THC (1 microM) inhibited excitatory postsynaptic currents (EPSCs) and whole-cell I(Ca) evoked at 0.1 Hz but at 0.5 Hz THC had little effect. The cannabinoid receptor full agonists [(R)-(+)-[2,3-dihydro-5-methyl-3[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl)methanone mesylate salt] (Win55212-2) (100 nM) and 2-arachidonylglycerol (1 microM) inhibited EPSCs independent of stimulation at 0.1 or 0.5 Hz. THC occupied CB1 receptors at 0.5 Hz, but the receptors failed to couple to presynaptic Ca(2+) channels. Consequently, 1 microM THC blocked the inhibition of EPSC amplitude by Win55212-2 when EPSCs were evoked at 0.5 Hz. A depolarizing prepulse to 0 mV reversed THC inhibition of I(Ca), but reversal of the inhibition produced by Win55212-2 required a pulse to +80 mV, suggesting that the voltage-dependent reversal of Gbetagamma inhibition of voltage-gated Ca(2+) channels accounts for the frequency-dependence of cannabinoid action. THC blocked depolarization-induced suppression of EPSCs evoked at 0.5 Hz, indicating that it inhibited retrograde endocannabinoid signaling in a frequency-dependent manner. Thus, THC displayed a state-dependent switching from agonist to antagonist that may account for its complex actions in vivo.
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Affiliation(s)
- Alan M Roloff
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
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