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Zhang W, Zhao X, Bhuiyan P, Liu H, Wei H. Neuroprotective effects of dantrolene in neurodegenerative disease: Role of inhibition of pathological inflammation. JOURNAL OF ANESTHESIA AND TRANSLATIONAL MEDICINE 2024; 3:27-35. [PMID: 38826587 PMCID: PMC11138240 DOI: 10.1016/j.jatmed.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Neurodegenerative diseases (NDs) refer to a group of diseases in which slow, continuous cell death is the main pathogenic event in the nervous system. Most NDs are characterized by cognitive dysfunction or progressive motor dysfunction. Treatments of NDs mainly target alleviating symptoms, and most NDs do not have disease-modifying drugs. The pathogenesis of NDs involves inflammation and apoptosis mediated by mitochondrial dysfunction. Dantrolene, approved by the US Food and Drug Administration, acts as a RyRs antagonist for the treatment of malignant hyperthermia, spasticity, neuroleptic syndrome, ecstasy intoxication and exertional heat stroke with tolerable side effects. Recently, dantrolene has also shown therapeutic effects in some NDs. Its neuroprotective mechanisms include the reduction of excitotoxicity, apoptosis and neuroinflammation. In summary, dantrolene can be considered as a potential therapeutic candidate for NDs.
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Affiliation(s)
- Wenjia Zhang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Anesthesiology, Shandong Provincial Hospital, Shandong First Medical University, Jinan, Shandong 250021, China
| | - Xu Zhao
- Department of Anesthesiology, Shandong Provincial Hospital, Shandong First Medical University, Jinan, Shandong 250021, China
| | - Piplu Bhuiyan
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Henry Liu
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Huafeng Wei
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Torres R, Hidalgo C. Subcellular localization and transcriptional regulation of brain ryanodine receptors. Functional implications. Cell Calcium 2023; 116:102821. [PMID: 37949035 DOI: 10.1016/j.ceca.2023.102821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/16/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
Ryanodine receptors (RyR) are intracellular Ca2+ channels localized in the endoplasmic reticulum, where they act as critical mediators of Ca2+-induced Ca2+ calcium release (CICR). In the brain, mammals express in both neurons, and non-neuronal cells, a combination of the three RyR-isoforms (RyR1-3). Pharmacological approaches, which do not distinguish between isoforms, have indicated that RyR-isoforms contribute to brain function. However, isoform-specific manipulations have revealed that RyR-isoforms display different subcellular localizations and are differentially associated with neuronal function. These findings raise the need to understand RyR-isoform specific transcriptional regulation, as this knowledge will help to elucidate the causes of neuronal dysfunction for a growing list of brain disorders that show altered RyR channel expression and function.
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Affiliation(s)
- Rodrigo Torres
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Lago Panguipulli 1390, 5501842, Puerto Montt, Chile.
| | - Cecilia Hidalgo
- Department of Neurosciences. Biomedical Neuroscience Institute, Physiology and Biophysics Program, Institute of Biomedical Sciences, Center for Exercise, Metabolism and Cancer Studies, Faculty of Medicine, Universidad de Chile, Santiago, 8380000, Chile
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3
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Barber KR, Vizcarra VS, Zilch A, Majuta L, Diezel CC, Culver OP, Hughes BW, Taniguchi M, Streicher JM, Vanderah TW, Riegel AC. The Role of Ryanodine Receptor 2 in Drug-Associated Learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.03.560743. [PMID: 37873212 PMCID: PMC10592901 DOI: 10.1101/2023.10.03.560743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Type-2 ryanodine receptor (RyR2) ion channels facilitate the release of Ca 2+ from stores and serve an important function in neuroplasticity. The role for RyR2 in hippocampal-dependent learning and memory is well established and chronic hyperphosphorylation of RyR2 (RyR2P) is associated with pathological calcium leakage and cognitive disorders, including Alzheimer's disease. By comparison, little is known about the role of RyR2 in the ventral medial prefrontal cortex (vmPFC) circuitry important for working memory, decision making, and reward seeking. Here, we evaluated the basal expression and localization of RyR2 and RyR2P in the vmPFC. Next, we employed an operant model of sucrose, cocaine, or morphine self-administration (SA) followed by a (reward-free) recall test, to reengage vmPFC neurons and reactivate reward-seeking and re-evaluated the expression and localization of RyR2 and RyR2P in vmPFC. Under basal conditions, RyR2 was expressed in pyramidal cells but not regularly detected in PV/SST interneurons. On the contrary, RyR2P was rarely observed in PFC somata and was restricted to a different subcompartment of the same neuron - the apical dendrites of layer-5 pyramidal cells. Chronic SA of drug (cocaine or morphine) and nondrug (sucrose) rewards produced comparable increases in RyR2 protein expression. However, recalling either drug reward impaired the usual localization of RyR2P in dendrites and markedly increased its expression in somata immunoreactive for Fos, a marker of highly activated neurons. These effects could not be explained by chronic stress or drug withdrawal and instead appeared to require a recall experience associated with prior drug SA. In addition to showing the differential distribution of RyR2/RyR2P and affirming the general role of vmPFC in reward learning, this study provides information on the propensity of addictive drugs to redistribute RyR2P ion channels in a neuronal population engaged in drug-seeking. Hence, focusing on the early impact of addictive drugs on RyR2 function may serve as a promising approach to finding a treatment for substance use disorders.
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4
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Alkazmi L, Al-Kuraishy HM, Al-Gareeb AI, El-Bouseary MM, Ahmed EA, Batiha GES. Dantrolene and ryanodine receptors in COVID-19: The daunting task and neglected warden. Clin Exp Pharmacol Physiol 2023; 50:335-352. [PMID: 36732880 DOI: 10.1111/1440-1681.13756] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/10/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023]
Abstract
Dantrolene (DTN) is a ryanodine receptor (RyR) antagonist that inhibits Ca2+ release from stores in the sarcoplasmic reticulum. DTN is mainly used in the management of malignant hyperthermia. RyRs are highly expressed in immune cells and are involved in different viral infections, including severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), because Ca2+ is necessary for viral replication, maturation and release. DTN can inhibit the proliferation of SARS-CoV-2, indicating its potential role in reducing entry and pathogenesis of SARS-CoV-2. DTN may increase clearance of SARS-CoV-2 and promote coronavirus disease 2019 (COVID-19) recovery by shortening the period of infection. DTN inhibits N-methyl-D-aspartate (NMDA) mediated platelets aggregations and thrombosis. Therefore, DTN may inhibit thrombosis and coagulopathy in COVID-19 through suppression of platelet NMDA receptors. Moreover, DTN has a neuroprotective effect against SARS-CoV-2 infection-induced brain injury through modulation of NMDA receptors, which are involved in excitotoxicity, neuronal injury and the development of neuropsychiatric disorders. In conclusion, DTN by inhibiting RyRs may attenuate inflammatory disorders in SARS-CoV-2 infection and associated cardio-pulmonary complications. Therefore, DNT could be a promising drug therapy against COVID-19. Preclinical and clinical studies are warranted in this regards.
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Affiliation(s)
- Luay Alkazmi
- Biology Department, Faculty of Applied Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Hayder M Al-Kuraishy
- Department of Clinical Pharmacology and Medicine, College of Medicine, Al-Mustansiriya University, Baghdad, Iraq
| | - Ali I Al-Gareeb
- Department of Clinical Pharmacology and Medicine, College of Medicine, Al-Mustansiriya University, Baghdad, Iraq
| | - Maisra M El-Bouseary
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Eman A Ahmed
- Department of Pharmacology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
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5
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Orem BC, Morehouse JR, Ames S, Burke DA, Magnuson DS, Stirling DP. Direct Ryanodine Receptor-2 Knockout in Primary Afferent Fibers Modestly Affects Neurological Recovery after Contusive Spinal Cord Injury. Neurotrauma Rep 2022; 3:433-446. [PMID: 36337076 PMCID: PMC9622210 DOI: 10.1089/neur.2022.0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Neuronal ryanodine receptors (RyR) release calcium from internal stores and play a key role in synaptic plasticity, learning, and memory. Dysregulation of RyR function contributes to neurodegeneration and negatively impacts neurological recovery after spinal cord injury (SCI). However, the individual role of RyR isoforms and the underlying mechanisms remain poorly understood. To determine whether RyR2 plays a direct role in axonal fate and functional recovery after SCI, we bred Advillin-Cre: tdTomato (Ai9) reporter mice with "floxed" RyR2 mice to directly knock out (KO) RyR2 function in dorsal root ganglion neurons and their spinal projections. Adult 6- to 8-week-old RyR2KO and littermate controls were subjected to a contusive SCI and their dorsal column axons were imaged in vivo using two-photon excitation microscopy. We found that direct RyR2KO in dorsal column primary afferents did not significantly alter secondary axonal degeneration after SCI. We next assessed behavioral recovery after SCI and found that direct RyR2KO in primary afferents worsened open-field locomotor scores (Basso Mouse Scale subscore) compared to littermate controls. However, both TreadScan™ gait analysis and overground kinematic gait analysis tests revealed subtle, but no fundamental, differences in gait patterns between the two groups after SCI. Subsequent removal of spared afferent fibers using a dorsal column crush revealed similar outcomes in both groups. Analysis of primary afferents at the lumbar (L3-L5) level similarly revealed no noticeable differences between groups. Together, our results support a modest contribution of dorsal column primary afferent RyR2 in neurological recovery after SCI.
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Affiliation(s)
- Ben C. Orem
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA.,Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky, USA
| | - Johnny R. Morehouse
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA
| | - Spencer Ames
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA
| | - Darlene A. Burke
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA
| | - David S.K. Magnuson
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA.,Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky, USA.,Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky, USA
| | - David P. Stirling
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA.,Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky, USA.,Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky, USA.,Department of Microbiology and Immunology, University of Louisville, School of Medicine, Louisville, Kentucky, USA.,*Address correspondence to: David P. Stirling, PhD, Departments of Neurological Surgery, Microbiology and Immunology, and Anatomical Sciences and Neurobiology, KY Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd Street, MDR Building, Room 608, Louisville, KY 40202, USA.
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6
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Role of Microglia and Astrocytes in Alzheimer’s Disease: From Neuroinflammation to Ca2+ Homeostasis Dysregulation. Cells 2022; 11:cells11172728. [PMID: 36078138 PMCID: PMC9454513 DOI: 10.3390/cells11172728] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia worldwide, with a complex, poorly understood pathogenesis. Cerebral atrophy, amyloid-β (Aβ) plaques, and neurofibrillary tangles represent the main pathological hallmarks of the AD brain. Recently, neuroinflammation has been recognized as a prominent feature of the AD brain and substantial evidence suggests that the inflammatory response modulates disease progression. Additionally, dysregulation of calcium (Ca2+) homeostasis represents another early factor involved in the AD pathogenesis, as intracellular Ca2+ concentration is essential to ensure proper cellular and neuronal functions. Although growing evidence supports the involvement of Ca2+ in the mechanisms of neurodegeneration-related inflammatory processes, scant data are available on its contribution in microglia and astrocytes functioning, both in health and throughout the AD continuum. Nevertheless, AD-related aberrant Ca2+ signalling in astrocytes and microglia is crucially involved in the mechanisms underpinning neuroinflammatory processes that, in turn, impact neuronal Ca2+ homeostasis and brain function. In this light, we attempted to provide an overview of the current understanding of the interactions between the glia cells-mediated inflammatory responses and the molecular mechanisms involved in Ca2+ homeostasis dysregulation in AD.
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7
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Orem BC, Rajaee A, Stirling DP. Inhibiting Calcium Release from Ryanodine Receptors Protects Axons after Spinal Cord Injury. J Neurotrauma 2022; 39:311-319. [PMID: 34913747 PMCID: PMC8817717 DOI: 10.1089/neu.2021.0350] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Ryanodine receptors (RyRs) mediate calcium release from calcium stores and have been implicated in axonal degeneration. Here, we use an intravital imaging approach to determine axonal fate after spinal cord injury (SCI) in real-time and assess the efficacy of ryanodine receptor inhibition as a potential therapeutic approach to prevent intra-axonal calcium-mediated axonal degeneration. Adult 6-8 week old Thy1YFP transgenic mice that express YFP in axons, as well as triple transgenic Avil-Cre:Ai9:Ai95 mice that express the genetically-encoded calcium indicator GCaMP6f in tdTomato positive axons, were used to visualize axons and calcium changes in axons, respectively. Mice received a mild SCI at the T12 level of the spinal cord. Ryanodine, a RyR antagonist, was given at a concentration of 50 μM intrathecally within 15 min of SCI or delayed 3 h after injury and compared with vehicle-treated mice. RyR inhibition within 15 min of SCI significantly reduced axonal spheroid formation from 1 h to 24 h after SCI and increased axonal survival compared with vehicle controls. Delayed ryanodine treatment increased axonal survival and reduced intra-axonal calcium levels at 24 h after SCI but had no effect on axonal spheroid formation. Together, our results support a role for RyR in secondary axonal degeneration.
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Affiliation(s)
- Ben C. Orem
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky, USA
| | - Arezoo Rajaee
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky, USA
| | - David P. Stirling
- Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky, USA
- Department of Microbiology and Immunology, University of Louisville, School of Medicine, Louisville, Kentucky, USA
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8
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Ovcjak A, Xiao A, Kim JS, Xu B, Szeto V, Turlova E, Abussaud A, Chen NH, Miller SP, Sun HS, Feng ZP. Ryanodine receptor inhibitor dantrolene reduces hypoxic-ischemic brain injury in neonatal mice. Exp Neurol 2022; 351:113985. [DOI: 10.1016/j.expneurol.2022.113985] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 01/07/2022] [Accepted: 01/13/2022] [Indexed: 11/04/2022]
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9
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Guan PP, Cao LL, Yang Y, Wang P. Calcium Ions Aggravate Alzheimer's Disease Through the Aberrant Activation of Neuronal Networks, Leading to Synaptic and Cognitive Deficits. Front Mol Neurosci 2021; 14:757515. [PMID: 34924952 PMCID: PMC8674839 DOI: 10.3389/fnmol.2021.757515] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/04/2021] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disease that is characterized by the production and deposition of β-amyloid protein (Aβ) and hyperphosphorylated tau, leading to the formation of β-amyloid plaques (APs) and neurofibrillary tangles (NFTs). Although calcium ions (Ca2+) promote the formation of APs and NFTs, no systematic review of the mechanisms by which Ca2+ affects the development and progression of AD has been published. Therefore, the current review aimed to fill the gaps between elevated Ca2+ levels and the pathogenesis of AD. Specifically, we mainly focus on the molecular mechanisms by which Ca2+ affects the neuronal networks of neuroinflammation, neuronal injury, neurogenesis, neurotoxicity, neuroprotection, and autophagy. Furthermore, the roles of Ca2+ transporters located in the cell membrane, endoplasmic reticulum (ER), mitochondria and lysosome in mediating the effects of Ca2+ on activating neuronal networks that ultimately contribute to the development and progression of AD are discussed. Finally, the drug candidates derived from herbs used as food or seasoning in Chinese daily life are summarized to provide a theoretical basis for improving the clinical treatment of AD.
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Affiliation(s)
- Pei-Pei Guan
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Long-Long Cao
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Yi Yang
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Pu Wang
- College of Life and Health Sciences, Northeastern University, Shenyang, China
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10
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Keilhoff G, Pinkernelle J, Fansa H. The Ryanodine receptor stabilizer S107 fails to support motor neuronal neuritogenesis in vitro. Tissue Cell 2021; 73:101625. [PMID: 34419737 DOI: 10.1016/j.tice.2021.101625] [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: 06/11/2021] [Revised: 08/02/2021] [Accepted: 08/15/2021] [Indexed: 11/30/2022]
Abstract
Calcium homeostasis is essential for neuronal cell survival/differentiation. Imbalance of the Ca2+ homeostasis due to excessive Ca2+ overload is essential for spinal cord injury (SCI). The overload resulted from Ca2+ flux across the plasma membrane and from internal Ca2+ store release (mitochondria, endoplasmic reticulum, ER). Inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) are involved in releasing Ca2+ from ER contributing to axonal degeneration following SCI. In turn, block of both receptors is axoprotective. The calstabin RyR subunit, stabilizing the channel in a state of reduced activity, prevents pathological Ca2+ release too. We investigated whether S107, a RyR-stabilizing compound (Rycal), is beneficial for survival and neuritogenesis of spinal cord motor neurons in vitro. We used a spinal cord slice model and the motor neuron-like NSC-34 cell line. Effects of S107 were tested by propidium iodide/fluorescein diacetate vital staining, mitotic index determination via BrdU-incorporation, and neurite sprouting parameters. Results showed that S107 (i) had no effect on gliosis resulting from slices preparation; (ii) had no effect on motor neuronal survival and proliferation; and (iii) impaired neurite sprouting, no matter whether it was a differentiation (NSC-34 cells) or regeneration (spinal cord slices) process. The results underline the need for a flexible Ca2+homeostasis provided by the ER for re-initiation of neuritogenesis.
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Affiliation(s)
- Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, 39120, Magdeburg, Germany.
| | - Josephine Pinkernelle
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, 39120, Magdeburg, Germany
| | - Hisham Fansa
- Department of Plastic, Reconstructive, and Aesthetic Surgery, Hand Surgery, Klinikum Bielefeld, OWL-University, 33604, Bielefeld, Germany; Department of Plastic Surgery, and Breast Centre, Spital Zollikerberg, 8125, Zollikerberg, Switzerland
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11
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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12
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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13
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Therapeutic Strategies to Target Calcium Dysregulation in Alzheimer's Disease. Cells 2020; 9:cells9112513. [PMID: 33233678 PMCID: PMC7699688 DOI: 10.3390/cells9112513] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/31/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia, affecting millions of people worldwide. Unfortunately, none of the current treatments are effective at improving cognitive function in AD patients and, therefore, there is an urgent need for the development of new therapies that target the early cause(s) of AD. Intracellular calcium (Ca2+) regulation is critical for proper cellular and neuronal function. It has been suggested that Ca2+ dyshomeostasis is an upstream factor of many neurodegenerative diseases, including AD. For this reason, chemical agents or small molecules aimed at targeting or correcting this Ca2+ dysregulation might serve as therapeutic strategies to prevent the development of AD. Moreover, neurons are not alone in exhibiting Ca2+ dyshomeostasis, since Ca2+ disruption is observed in other cell types in the brain in AD. In this review, we examine the distinct Ca2+ channels and compartments involved in the disease mechanisms that could be potential targets in AD.
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14
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Matelski L, Keil Stietz KP, Sethi S, Taylor SL, Van de Water J, Lein PJ. The influence of sex, genotype, and dose on serum and hippocampal cytokine levels in juvenile mice developmentally exposed to a human-relevant mixture of polychlorinated biphenyls. Curr Res Toxicol 2020; 1:85-103. [PMID: 34296199 PMCID: PMC8294704 DOI: 10.1016/j.crtox.2020.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Polychlorinated biphenyls (PCBs) are pervasive environmental contaminants implicated as risk factors for neurodevelopmental disorders (NDDs). Immune dysregulation is another NDD risk factor, and developmental PCB exposures are associated with early life immune dysregulation. Studies of the immunomodulatory effects of PCBs have focused on the higher-chlorinated congeners found in legacy commercial mixtures. Comparatively little is known about the immune effects of contemporary, lower-chlorinated PCBs. This is a critical data gap given recent reports that lower-chlorinated congeners comprise >70% of the total PCB burden in serum of pregnant women enrolled in the MARBLES study who are at increased risk for having a child with an NDD. To examine the influence of PCBs, sex, and genotype on cytokine levels, mice were exposed throughout gestation and lactation to a PCB mixture in the maternal diet, which was based on the 12 most abundant PCBs in sera from MARBLES subjects. Using multiplex array, cytokines were quantified in the serum and hippocampus of weanling mice expressing either a human gain-of-function mutation in ryanodine receptor 1 (T4826I mice), a human CGG premutation repeat expansion in the fragile X mental retardation gene 1 (CGG mice), or both mutations (DM mice). Congenic wildtype (WT) mice were used as controls. There were dose-dependent effects of PCB exposure on cytokine concentrations in the serum but not hippocampus. Differential effects of genotype were observed in the serum and hippocampus. Hippocampal cytokines were consistently elevated in T4826I mice and also in WT animals for some cytokines compared to CGG and DM mice, while serum cytokines were usually elevated in the mutant genotypes compared to the WT group. Males had elevated levels of 19 cytokines in the serum and 4 in the hippocampus compared to females, but there were also interactions between sex and genotype for 7 hippocampal cytokines. Only the chemokine CCL5 in the serum showed an interaction between PCB dose, genotype, and sex. Collectively, these findings indicate differential influences of PCB exposure and genotype on cytokine levels in serum and hippocampal tissue of weanling mice. These results suggest that developmental PCB exposure has chronic effects on baseline serum, but not hippocampal, cytokine levels in juvenile mice.
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Affiliation(s)
- Lauren Matelski
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA
| | - Kimberly P. Keil Stietz
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA
| | - Sunjay Sethi
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA
| | - Sandra L. Taylor
- Division of Biostatistics, Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA 95616, USA
| | - Judy Van de Water
- MIND Institute, University of California, Davis, School of Medicine, Sacramento, CA 95817, USA,Division of Rheumatology, Allergy, and Clinical Immunology, Department of Internal Medicine, University of California, Davis, School of Medicine, Davis, CA 95616, USA
| | - Pamela J. Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA,MIND Institute, University of California, Davis, School of Medicine, Sacramento, CA 95817, USA,Corresponding author at: Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA.
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15
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Polysialic acid and Siglec-E orchestrate negative feedback regulation of microglia activation. Cell Mol Life Sci 2020; 78:1637-1653. [PMID: 32725371 PMCID: PMC7904730 DOI: 10.1007/s00018-020-03601-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 06/23/2020] [Accepted: 07/17/2020] [Indexed: 11/09/2022]
Abstract
Polysialic acid (polySia) emerges as a novel regulator of microglia activity. We recently identified polysialylated proteins in the Golgi compartment of murine microglia that are released in response to inflammatory stimulation. Since exogenously added polySia is able to attenuate the inflammatory response, we proposed that the release of polysialylated proteins constitutes a mechanism for negative feedback regulation of microglia activation. Here, we demonstrate that translocation of polySia from the Golgi to the cell surface can be induced by calcium depletion of the Golgi compartment and that polysialylated proteins are continuously released for at least 24 h after the onset of inflammatory stimulation. The latter was unexpected, because polySia signals detected by immunocytochemistry are rapidly depleted. However, it indicates that the amount of released polySia is much higher than anticipated based on immunostaining. This may be crucial for microglial responses during traumatic brain injury (TBI), as we detected polySia signals in activated microglia around a stab wound in the adult mouse brain. In BV2 microglia, the putative polySia receptor Siglec-E is internalized during lipopolysaccharide (LPS)-induced activation and in response to polySia exposure, indicating interaction. Correspondingly, CRISPR/Cas9-mediated Siglec-E knockout prevents inhibition of pro inflammatory activation by exogenously added polySia and leads to a strong increase of the LPS response. A comparable increase of LPS-induced activation has been observed in microglia with abolished polySia synthesis. Together, these results indicate that the release of the microglia-intrinsic polySia pool, as implicated in TBI, inhibits the inflammatory response by acting as a trans-activating ligand of Siglec-E.
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16
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Sermersheim M, Kenney AD, Lin PH, McMichael TM, Cai C, Gumpper K, Adesanya TMA, Li H, Zhou X, Park KH, Yount JS, Ma J. MG53 suppresses interferon-β and inflammation via regulation of ryanodine receptor-mediated intracellular calcium signaling. Nat Commun 2020; 11:3624. [PMID: 32681036 PMCID: PMC7368064 DOI: 10.1038/s41467-020-17177-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 06/02/2020] [Indexed: 01/19/2023] Open
Abstract
TRIM family proteins play integral roles in the innate immune response to virus infection. MG53 (TRIM72) is essential for cell membrane repair and is believed to be a muscle-specific TRIM protein. Here we show human macrophages express MG53, and MG53 protein expression is reduced following virus infection. Knockdown of MG53 in macrophages leads to increases in type I interferon (IFN) upon infection. MG53 knockout mice infected with influenza virus show comparable influenza virus titres to wild type mice, but display increased morbidity accompanied by more accumulation of CD45+ cells and elevation of IFNβ in the lung. We find that MG53 knockdown results in activation of NFκB signalling, which is linked to an increase in intracellular calcium oscillation mediated by ryanodine receptor (RyR). MG53 inhibits IFNβ induction in an RyR-dependent manner. This study establishes MG53 as a new target for control of virus-induced morbidity and tissue injury.
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Affiliation(s)
- Matthew Sermersheim
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Adam D Kenney
- Department of Microbial Infection and Immunity, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Pei-Hui Lin
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Temet M McMichael
- Department of Microbial Infection and Immunity, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Chuanxi Cai
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Kristyn Gumpper
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - T M Ayodele Adesanya
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Haichang Li
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Xinyu Zhou
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ki-Ho Park
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Jacob S Yount
- Department of Microbial Infection and Immunity, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
| | - Jianjie Ma
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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17
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Sex-specific effects of developmental exposure to polychlorinated biphenyls on neuroimmune and dopaminergic endpoints in adolescent rats. Neurotoxicol Teratol 2020; 79:106880. [PMID: 32259577 DOI: 10.1016/j.ntt.2020.106880] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 12/22/2022]
Abstract
Exposure to environmental contaminants early in life can have long lasting consequences for physiological function. Polychlorinated biphenyls (PCBs) are a group of ubiquitous contaminants that perturb endocrine signaling and have been associated with altered immune function in children. In this study, we examined the effects of developmental exposure to PCBs on neuroimmune responses to an inflammatory challenge during adolescence. Sprague Dawley rat dams were exposed to a PCB mixture (Aroclor 1242, 1248, 1254, 1:1:1, 20 μg/kg/day) or oil control throughout pregnancy, and adolescent male and female offspring were injected with lipopolysaccharide (LPS, 50 μg/kg, ip) or saline control prior to euthanasia. Gene expression profiling was conducted in the hypothalamus, prefrontal cortex, striatum, and midbrain. In the hypothalamus, PCBs increased expression of genes involved in neuroimmune function, including those within the nuclear factor kappa b (NF-κB) complex, independent of LPS challenge. PCB exposure also increased expression of receptors for dopamine, serotonin, and estrogen in this region. In contrast, in the prefrontal cortex, PCB exposure blunted or induced irregular neuroimmune gene expression responses to LPS challenge. Moreover, neither PCB nor LPS exposure altered expression of neurotransmitter receptors throughout the mesocorticolimbic circuit. Almost all effects were present in males but not females, in agreement with the idea that male neuroimmune cells are more sensitive to perturbation and emphasizing the importance of studying both male and female subjects. Given that altered neuroimmune signaling has been implicated in mental health and substance abuse disorders that often begin during adolescence, these results highlight neuroimmune processes as another mechanism by which early life PCBs can alter brain function later in life.
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18
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Strategies for Neuroprotection in Multiple Sclerosis and the Role of Calcium. Int J Mol Sci 2020; 21:ijms21051663. [PMID: 32121306 PMCID: PMC7084497 DOI: 10.3390/ijms21051663] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/16/2020] [Accepted: 02/26/2020] [Indexed: 12/12/2022] Open
Abstract
Calcium ions are vital for maintaining the physiological and biochemical processes inside cells. The central nervous system (CNS) is particularly dependent on calcium homeostasis and its dysregulation has been associated with several neurodegenerative disorders including Parkinson’s disease (PD), Alzheimer’s disease (AD) and Huntington’s disease (HD), as well as with multiple sclerosis (MS). Hence, the modulation of calcium influx into the cells and the targeting of calcium-mediated signaling pathways may present a promising therapeutic approach for these diseases. This review provides an overview on calcium channels in neurons and glial cells. Special emphasis is put on MS, a chronic autoimmune disease of the CNS. While the initial relapsing-remitting stage of MS can be treated effectively with immune modulatory and immunosuppressive drugs, the subsequent progressive stage has remained largely untreatable. Here we summarize several approaches that have been and are currently being tested for their neuroprotective capacities in MS and we discuss which role calcium could play in this regard.
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19
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Hopp SC. Targeting microglia L-type voltage-dependent calcium channels for the treatment of central nervous system disorders. J Neurosci Res 2020; 99:141-162. [PMID: 31997405 DOI: 10.1002/jnr.24585] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/03/2020] [Accepted: 01/08/2020] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+ ) is a ubiquitous mediator of a multitude of cellular functions in the central nervous system (CNS). Intracellular Ca2+ is tightly regulated by cells, including entry via plasma membrane Ca2+ permeable channels. Of specific interest for this review are L-type voltage-dependent Ca2+ channels (L-VDCCs), due to their pleiotropic role in several CNS disorders. Currently, there are numerous approved drugs that target L-VDCCs, including dihydropyridines. These drugs are safe and effective for the treatment of humans with cardiovascular disease and may also confer neuroprotection. Here, we review the potential of L-VDCCs as a target for the treatment of CNS disorders with a focus on microglia L-VDCCs. Microglia, the resident immune cells of the brain, have attracted recent attention for their emerging inflammatory role in several CNS diseases. Intracellular Ca2+ regulates microglia transition from a resting quiescent state to an "activated" immune-effector state and is thus a valuable target for manipulation of microglia phenotype. We will review the literature on L-VDCC expression and function in the CNS and on microglia in vitro and in vivo and explore the therapeutic landscape of L-VDCC-targeting agents at present and future challenges in the context of Alzheimer's disease, Parkinson's disease, Huntington's disease, neuropsychiatric diseases, and other CNS disorders.
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Affiliation(s)
- Sarah C Hopp
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health Science Center San Antonio, San Antonio, TX, USA.,Department of Pharmacology, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
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20
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Lue LF, Beach TG, Walker DG. Alzheimer's Disease Research Using Human Microglia. Cells 2019; 8:cells8080838. [PMID: 31387311 PMCID: PMC6721636 DOI: 10.3390/cells8080838] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 02/06/2023] Open
Abstract
Experimental studies of neuroinflammation in Alzheimer's disease (AD) have mostly investigated microglia, the brain-resident macrophages. This review focused on human microglia obtained at rapid autopsies. Studies employing methods to isolate and culture human brain microglia in high purity for experimental studies were discussed. These methods were employed to isolate human microglia for investigation of a number of features of neuroinflammation, including activation phenotypes, neurotoxicity, responses to abnormal aggregated proteins such as amyloid beta, phagocytosis, and the effects of aging and disease on microglia cellular properties. In recent years, interest in human microglia and neuroinflammation has been renewed due to the identification of inflammation-related AD genetic risk factors, in particular the triggering receptor expressed on myeloid cells (TREM)-2. Because of the difficulties in developing effective treatments for AD, there has been a general need for greater understanding of the functions of microglia in normal and AD brains. While most experimental studies on neuroinflammation have employed rodent microglia, this review considered the role of human microglia in experimental studies. This review focused on the development of in vitro methodology for the culture of postmortem human microglia and the key findings obtained from experimental studies with these cells.
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Affiliation(s)
- Lih-Fen Lue
- Banner Sun Health Research Institute, Sun City, AZ, 85351, USA.
- Neurodegenerative Disease Research Center and School of Life Sciences, Arizona State University, Tempe, AZ 84027, USA.
| | - Thomas G Beach
- Banner Sun Health Research Institute, Sun City, AZ, 85351, USA
| | - Douglas G Walker
- Neurodegenerative Disease Research Center and School of Life Sciences, Arizona State University, Tempe, AZ 84027, USA
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu 520, Japan
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21
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Abstract
Microglial cells derive from fetal macrophages which immigrate into and disseminate throughout the central nervous system (CNS) in early embryogenesis. After settling in the nerve tissue, microglial progenitors acquire an idiosyncratic morphological phenotype with small cell body and moving thin and highly ramified processes currently defined as "resting or surveillant microglia". Physiology of microglia is manifested by second messenger-mediated cellular excitability, low resting membrane conductance, and expression of receptors to pathogen- or damage-associated molecular patterns (PAMPs and DAMPs), as well as receptors to classical neurotransmitters and neurohormones. This specific physiological profile reflects adaptive changes of myeloid cells to the CNS environment.
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Affiliation(s)
- Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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22
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Roshan MHK, Tambo A, Pace NP. Potential Role of Caffeine in the Treatment of Parkinson's Disease. Open Neurol J 2016; 10:42-58. [PMID: 27563362 PMCID: PMC4962431 DOI: 10.2174/1874205x01610010042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/30/2016] [Accepted: 05/02/2016] [Indexed: 12/20/2022] Open
Abstract
Parkinson’s disease [PD] is the second most common neurodegenerative disorder after Alzheimer’s disease, affecting 1% of the population over the age of 55. The underlying neuropathology seen in PD is characterised by progressive loss of dopaminergic neurons in the substantia nigra pars compacta with the presence of Lewy bodies. The Lewy bodies are composed of aggregates of α-synuclein. The motor manifestations of PD include a resting tremor, bradykinesia, and muscle rigidity. Currently there is no cure for PD and motor symptoms are treated with a number of drugs including levodopa [L-dopa]. These drugs do not delay progression of the disease and often provide only temporary relief. Their use is often accompanied by severe adverse effects. Emerging evidence from both in vivo and in vitro studies suggests that caffeine may reduce parkinsonian motor symptoms by antagonising the adenosine A2A receptor, which is predominately expressed in the basal ganglia. It is hypothesised that caffeine may increase the excitatory activity in local areas by inhibiting the astrocytic inflammatory processes but evidence remains inconclusive. In addition, the co-administration of caffeine with currently available PD drugs helps to reduce drug tolerance, suggesting that caffeine may be used as an adjuvant in treating PD. In conclusion, caffeine may have a wide range of therapeutic effects which are yet to be explored, and therefore warrants further investigation in randomized clinical trials.
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Affiliation(s)
- Mohsin H K Roshan
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta- Msida, Malta
| | - Amos Tambo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta- Msida, Malta
| | - Nikolai P Pace
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta- Msida, Malta
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23
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Effect of ruthenium red, a ryanodine receptor antagonist in experimental diabetes induced vascular endothelial dysfunction and associated dementia in rats. Physiol Behav 2016; 164:140-50. [PMID: 27262216 DOI: 10.1016/j.physbeh.2016.05.052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 05/29/2016] [Accepted: 05/31/2016] [Indexed: 12/14/2022]
Abstract
Diabetes mellitus is considered as a main risk factor for vascular dementia. In the past, we have reported the induction of vascular dementia by experimental diabetes. This study investigates the efficacy of a ruthenium red, a ryanodine receptor antagonist and pioglitazone in the pharmacological interdiction of pancreatectomy diabetes (PaD) induced vascular endothelial dysfunction and subsequent vascular dementia in rats. Attentional set shifting and Morris water-maze test were used for assessment of learning and memory. Vascular endothelial function, blood brain barrier permeability, serum glucose, serum nitrite/nitrate, oxidative stress (viz. aortic superoxide anion, brain thiobarbituric acid reactive species and brain glutathione), brain calcium and inflammation (myeloperoxidase) were also estimated. PaD rats have shown impairment of endothelial function, blood brain barrier permeability, learning and memory along with an increase in brain inflammation, oxidative stress and calcium. Administration of ruthenium red and pioglitazone has significantly attenuated PaD induced impairment of learning, memory, blood brain barrier permeability, endothelial function and biochemical parameters. It may be concluded that ruthenium red, a ryanodine receptor antagonist and pioglitazone, a PPAR-γ agonist may be considered as potent pharmacological agent for the management of PaD induced endothelial dysfunction and subsequent vascular dementia. Ryanodine receptor may be explored further for their possible benefits in vascular dementia.
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24
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Hu QP, Mao DA. Histone deacetylase inhibitor SAHA attenuates post-seizure hippocampal microglia TLR4/MYD88 signaling and inhibits TLR4 gene expression via histone acetylation. BMC Neurosci 2016; 17:22. [PMID: 27193049 PMCID: PMC4872358 DOI: 10.1186/s12868-016-0264-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 05/11/2016] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Epilepsy is a common neurological disorder characterized by recurrent unprovoked seizures. Seizure-induced TLR4/MYD88 signaling plays a critical role in activating microglia and triggering neuron apoptosis. SAHA is a histone deacetylase inhibitor that regulates gene expression by increasing chromatin histone acetylation. In this study, we investigated the role of SAHA in TLR4/MYD88 signaling in a rat seizure model. RESULTS Sprague-Dawley rats with kainic acid (KA)-induced seizures were treated with SAHA. The expression of TLR4, MYD88, NF-κB P65 and IL-1β in hippocampus was detected at hour 2 and 6 and day 1, 2, and 3 post seizure. SAHA pretreatment increased seizure latency and decreased seizure scores. The expression levels of TLR4, MYD88, NF-κB and IL-1β increased significantly in both activated microglia and apoptotic neurons after KA treatment. The effects were attenuated by SAHA. Chromatin immunoprecipitation assays indicated that the H3 histone acetylation levels significantly decreased while H3K9 levels significantly increased in the KA treatment group. The H3 and H3K9 acetylation levels returned to control levels after SAHA (50 mg/kg) pretreatment. There was a positive correlation between the expression of TLR4 and the acetylation levels of H3K9. CONCLUSIONS Histone deacetylase inhibitor SAHA can suppress seizure-induced TLR4/MYD88 signaling and inhibit TLR4 gene expression through histone acetylation regulation. This suggests that SAHA may protect against seizure-induced brain damage.
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Affiliation(s)
- Qing-Peng Hu
- Department of Pediatrics, The Second Xiang-Ya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410011, Hunan, China
| | - Ding-An Mao
- Department of Pediatrics, The Second Xiang-Ya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410011, Hunan, China.
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25
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Rachmawati D, Peferoen LA, Vogel DY, Alsalem IW, Amor S, Bontkes HJ, von Blomberg BME, Scheper RJ, van Hoogstraten IM. Metal ions potentiate microglia responsiveness to endotoxin. J Neuroimmunol 2016; 291:89-95. [DOI: 10.1016/j.jneuroim.2015.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/14/2015] [Accepted: 12/28/2015] [Indexed: 12/14/2022]
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26
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Hopp SC, D'Angelo HM, Royer SE, Kaercher RM, Crockett AM, Adzovic L, Wenk GL. Calcium dysregulation via L-type voltage-dependent calcium channels and ryanodine receptors underlies memory deficits and synaptic dysfunction during chronic neuroinflammation. J Neuroinflammation 2015; 12:56. [PMID: 25888781 PMCID: PMC4377218 DOI: 10.1186/s12974-015-0262-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 02/09/2015] [Indexed: 11/23/2022] Open
Abstract
Background Chronic neuroinflammation and calcium (Ca+2) dysregulation are both components of Alzheimer’s disease. Prolonged neuroinflammation produces elevation of pro-inflammatory cytokines and reactive oxygen species which can alter neuronal Ca+2 homeostasis via L-type voltage-dependent Ca+2 channels (L-VDCCs) and ryanodine receptors (RyRs). Chronic neuroinflammation also leads to deficits in spatial memory, which may be related to Ca+2 dysregulation. Methods The studies herein use an in vivo model of chronic neuroinflammation: rats were infused intraventricularly with a continuous small dose of lipopolysaccharide (LPS) or artificial cerebrospinal fluid (aCSF) for 28 days. The rats were treated with the L-VDCC antagonist nimodipine or the RyR antagonist dantrolene. Results LPS-infused rats had significant memory deficits in the Morris water maze, and this deficit was ameliorated by treatment with nimodipine. Synaptosomes from LPS-infused rats had increased Ca+2 uptake, which was reduced by a blockade of L-VDCCs either in vivo or ex vivo. Conclusions Taken together, these data indicate that Ca+2 dysregulation during chronic neuroinflammation is partially dependent on increases in L-VDCC function. However, blockade of the RyRs also slightly improved spatial memory of the LPS-infused rats, demonstrating that other Ca+2 channels are dysregulated during chronic neuroinflammation. Ca+2-dependent immediate early gene expression was reduced in LPS-infused rats treated with dantrolene or nimodipine, indicating normalized synaptic function that may underlie improvements in spatial memory. Pro-inflammatory markers are also reduced in LPS-infused rats treated with either drug. Overall, these data suggest that Ca+2 dysregulation via L-VDCCs and RyRs play a crucial role in memory deficits resulting from chronic neuroinflammation.
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Affiliation(s)
- Sarah C Hopp
- Departments of Neuroscience, Ohio State University, Columbus, OH, 43210, USA.
| | - Heather M D'Angelo
- Department of Psychology, Ohio State University, 1835 Neil Ave, Columbus, OH, 43210, USA.
| | - Sarah E Royer
- Departments of Neuroscience, Ohio State University, Columbus, OH, 43210, USA.
| | - Roxanne M Kaercher
- Department of Psychology, Ohio State University, 1835 Neil Ave, Columbus, OH, 43210, USA.
| | - Alexis M Crockett
- Departments of Neuroscience, Ohio State University, Columbus, OH, 43210, USA. .,Department of Psychology, Ohio State University, 1835 Neil Ave, Columbus, OH, 43210, USA.
| | - Linda Adzovic
- Department of Psychology, Ohio State University, 1835 Neil Ave, Columbus, OH, 43210, USA.
| | - Gary L Wenk
- Departments of Neuroscience, Ohio State University, Columbus, OH, 43210, USA. .,Department of Psychology, Ohio State University, 1835 Neil Ave, Columbus, OH, 43210, USA.
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27
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Hopp SC, Royer SE, D’Angelo HM, Kaercher RM, Fisher DA, Wenk GL. Differential neuroprotective and anti-inflammatory effects of L-type voltage dependent calcium channel and ryanodine receptor antagonists in the substantia nigra and locus coeruleus. J Neuroimmune Pharmacol 2015; 10:35-44. [PMID: 25318607 PMCID: PMC4336597 DOI: 10.1007/s11481-014-9568-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 10/07/2014] [Indexed: 01/01/2023]
Abstract
Neuroinflammation and degeneration of catecholaminergic brainstem nuclei occur early in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Neuroinflammation increases levels of pro-inflammatory cytokines and reactive oxygen species which can alter neuronal calcium (Ca(+2)) homoeostasis via L-type voltage dependent calcium channels (L-VDCCs) and ryanodine receptors (RyRs). Alterations in Ca(+2) channel activity in the SN and LC can lead to disruption of normal pacemaking activity in these areas, contributing to behavioral deficits. Here, we utilized an in vivo model of chronic neuroinflammation: rats were infused intraventricularly with a continuous small dose (0.25 μg/h) of lipopolysaccharide (LPS) or artificial cerebrospinal fluid (aCSF) for 28 days. Rats were treated with either the L-VDCC antagonist nimodipine or the RyR antagonist dantrolene. LPS-infused rats had significant motor deficits in the accelerating rotarod task as well as abnormal behavioral agitation in the forced swim task and open field. Corresponding with these behavioral deficits, LPS-infused rats also had significant increases in microglia activation and loss of tyrosine hydroxylase (TH) immunoreactivity in the substantia nigra pars compacta (SNpc) and locus coeruleus (LC). Treatment with nimodipine or dantrolene normalized LPS-induced abnormalities in the rotarod and forced swim, restored the number of TH-immunoreactive cells in the LC, and significantly reduced microglia activation in the SNpc. Only nimodipine significantly reduced microglia activation in the LC, and neither drug increased TH immunoreactivity in the SNpc. These findings demonstrate that the Ca(+2) dysregulation in the LC and SN brainstem nuclei is differentially altered by chronic neuroinflammation. Overall, targeting Ca + 2 dysregulation may be an important target for ameliorating neurodegeneration in the SNpc and LC.
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Affiliation(s)
- Sarah C. Hopp
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | - Sarah E. Royer
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | | | | | | | - Gary L. Wenk
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
- Department of Psychology, Ohio State University, Columbus, OH, 43210, USA
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Hopp SC, D'Angelo HM, Royer SE, Kaercher RM, Adzovic L, Wenk GL. Differential rescue of spatial memory deficits in aged rats by L-type voltage-dependent calcium channel and ryanodine receptor antagonism. Neuroscience 2014; 280:10-8. [PMID: 25224829 DOI: 10.1016/j.neuroscience.2014.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/04/2014] [Accepted: 09/05/2014] [Indexed: 10/25/2022]
Abstract
Age-associated memory impairments may result as a consequence of neuroinflammatory induction of intracellular calcium (Ca(+2)) dysregulation. Altered L-type voltage-dependent calcium channel (L-VDCC) and ryanodine receptor (RyR) activity may underlie age-associated learning and memory impairments. Various neuroinflammatory markers are associated with increased activity of both L-VDCCs and RyRs, and increased neuroinflammation is associated with normal aging. In vitro, pharmacological blockade of L-VDCCs and RyRs has been shown to be anti-inflammatory. Here, we examined whether pharmacological blockade of L-VDCCs or RyRs with the drugs nimodipine and dantrolene, respectively, could improve spatial memory and reduce age-associated increases in microglia activation. Dantrolene and nimodipine differentially attenuated age-associated spatial memory deficits but were not anti-inflammatory in vivo. Furthermore, RyR gene expression was inversely correlated with spatial memory, highlighting the central role of Ca(+2) dysregulation in age-associated memory deficits.
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Affiliation(s)
- S C Hopp
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA
| | - H M D'Angelo
- Department of Psychology, Ohio State University, Columbus, OH 43210, USA
| | - S E Royer
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA
| | - R M Kaercher
- Department of Psychology, Ohio State University, Columbus, OH 43210, USA
| | - L Adzovic
- Department of Psychology, Ohio State University, Columbus, OH 43210, USA
| | - G L Wenk
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA; Department of Psychology, Ohio State University, Columbus, OH 43210, USA.
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Sharma P, Ping L. Calcium ion influx in microglial cells: physiological and therapeutic significance. J Neurosci Res 2014; 92:409-23. [PMID: 24464907 DOI: 10.1002/jnr.23344] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 11/09/2013] [Accepted: 11/12/2013] [Indexed: 01/16/2023]
Abstract
Microglial cells, the immunocompetent cells of the central nervous system (CNS), exhibit a resting phenotype under healthy conditions. In response to injury, however, they transform into an activated state, which is a hallmark feature of many CNS diseases. Factors or agents released from the neurons, blood vessels, and/or astrocytes could activate these cells, leading to their functional and structural modifications. Microglial cells are well equipped to sense environmental changes within the brain under both physiological and pathological conditions. Entry of calcium ions (Ca(2+)) plays a critical role in the process of microglial transformation; several channels and receptors have been identified on the surface of microglial cells. These include store-operated channel, Orai1, and its sensor protein, stromal interaction molecule 1 (STIM1), in microglial cells, and their functions are modulated under pathological stimulations. Transient receptor potential (TRP) channels and voltage- and ligand-gated channels (ionotropic and metabotropic receptors) are also responsible for Ca(2+) influx into the microglial cells. An elevation of intracellular Ca(2+) concentration subsequently regulates microglial cell functions by activating a diverse array of Ca(2+)-sensitive signaling cascades. Perturbed Ca(2+) homeostasis contributes to the progression of a number of CNS disorders. Thus, regulation of Ca(2+) entry into microglial cells could be a pharmacological target for several CNS-related pathological conditions. This Review addresses the recent insights into microglial cell Ca(2+) influx mechanisms, their roles in the regulation of functions, and alterations of Ca(2+) entry in specific CNS disorders.
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Affiliation(s)
- Purnima Sharma
- All India Institute of Medical Sciences-Physiology, Basni Industrial Area Phase II Jodhpur, Rajasthan, India
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Abstract
New concepts on potassium channel function in neuroinflammation suggest that they regulate mechanisms of microglial activation, including intracellular calcium homeostasis, morphological alterations, pro-inflammatory cytokine release, antigen presentation, and phagocytosis. Although little is known about voltage independent potassium channels in microglia, special attention emerges on small (SK/KCNN1-3/K(Ca)2) and intermediate (IK/KCNN4/K(Ca)3.1)-conductance calcium-activated potassium channels as regulators of microglial activation in the field of research on neuroinflammation and neurodegeneration. In particular, recent findings suggested that SK/K(Ca)2 channels, by regulating calcium homeostasis, may elicit a dual mechanism of action with protective properties in neurons and inhibition of inflammatory responses in microglia. Thus, modulating SK/K(Ca)2 channels and calcium signaling may provide novel therapeutic strategies in neurological disorders, where neuronal cell death and inflammatory responses concomitantly contribute to disease progression. Here, we review the particular role of SK/K(Ca)2 channels for [Ca(2+)](i) regulation in microglia and neurons, and we discuss the potential impact for further experimental approaches addressing novel therapeutic strategies in neurological diseases, where neuronal cell death and neuroinflammatory processes are prominent.
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Affiliation(s)
- Amalia M Dolga
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg Marburg, Germany
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Jantaratnotai N, McGeer PL, McLarnon JG. Mechanisms of Mg2+ inhibition of BzATP-dependent Ca2+ responses in THP-1 monocytes. Brain Res 2012; 1442:1-8. [PMID: 22297175 DOI: 10.1016/j.brainres.2012.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 12/14/2011] [Accepted: 01/04/2012] [Indexed: 12/31/2022]
Abstract
We have recently reported effects of Mg2+ to confer neuroprotection against toxicity of purinergic stimulated microglia and THP-1 monocytes. To examine mechanisms underlying neuroprotection, we have studied Mg2+ modulation of transient changes in intracellular Ca2+ ([Ca2+]i) in THP-1 cells induced by P2X7R agonist 2',3'-[benzoyl-4-benzoyl]-ATP (BzATP). Application of BzATP caused a rapid transient increase in [Ca2+]i followed by a prolonged component. The time course of the secondary slower phase was significantly reduced with Ca2+-free extracellular solution, with treatment of THP-1 cells by the P2X7R antagonist, oxATP or with exposure of cells to the store-operated channel (SOC) inhibitor, SKF96365. These results suggest that Ca2+ influx, mediated by both the P2X7R or by SOC, contribute to the slow component of [Ca2+]i. Treatment of THP-1 cells with 10 mMMg2+ was highly effective in reducing the time course of BzATP-induced Ca2+ decay; unlike the other modulatory protocols, Mg2+ markedly inhibited the amplitudes of slow and rapid components. In addition, acute application of Mg2+ during BzATP-induced responses elicited in the presence of either oxATP or SKF96365 to block respective P2X7R and SOC contributions, rapidly attenuated [Ca2+]i to baseline levels. Priming of cells with the inflammatory stimulus LPS/IFN-γ markedly enhanced the slower, but not rapid, phase of BzATP-induced [Ca2+]i with application of 10 mMMg2+ inhibiting both components of response. A model is proposed to account for BzATP stimulation of both ionotropic P2XR and metabotropic P2YR which provides a mechanistic basis for elevated Mg2+ anti-inflammatory and neuroprotective actions in inflamed brain.
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Affiliation(s)
- Nattinee Jantaratnotai
- Department of Anesthesiology, Pharmacology and Therapeutics, 2176 Health Sciences Mall, University of British Columbia, Vancouver, BC, Canada
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Ryanodine Receptors Are Expressed in Epidermal Keratinocytes and Associated with Keratinocyte Differentiation and Epidermal Permeability Barrier Homeostasis. J Invest Dermatol 2012; 132:69-75. [DOI: 10.1038/jid.2011.256] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
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Roodveldt C, Christodoulou J, Dobson CM. Immunological features of alpha-synuclein in Parkinson's disease. J Cell Mol Med 2008; 12:1820-9. [PMID: 18671754 PMCID: PMC4506153 DOI: 10.1111/j.1582-4934.2008.00450.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized pathologically by the presence, in the brain, of intra-cellular protein inclusions highly enriched in aggregated α-synuclein (αSyn), known as Lewy bodies. The onset of PD is accompanied by a local immune reaction in regions of the brain affected by the inclusions, although the mechanism that leads to pathogenesis is far from clear. It is, however, established that disease onset and progression are characterized by sustained activation of microglia, which is linked to significant dopaminergic neuron loss in the substantia nigra. A recent body of evidence indicates that aggregated or modified αSyn can indeed trigger the activation of microglia, inducing a lethal cascade of neuroinflammation and eventually, neuronal loss, pointing at aggregated and modified forms of αSyn as a primary cause of PD pathogenesis. By releasing toxic factors, or by phagocy-tosing neighbouring cells, activated microglia and astrocytes may form a self-perpetuating cycle for neuronal degeneration. Additional findings suggest a link between αSyn and humoural-mediated mechanisms in PD. In this review, we attempt to recapitulate our current understanding of PD physiopathology focused on αSyn and its links with the immune system, as well as of novel and promising therapeutic avenues for the treatment of PD and of other synucleinopathies.
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Affiliation(s)
- Cintia Roodveldt
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
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Sappington RM, Calkins DJ. Contribution of TRPV1 to microglia-derived IL-6 and NFkappaB translocation with elevated hydrostatic pressure. Invest Ophthalmol Vis Sci 2008; 49:3004-17. [PMID: 18362111 DOI: 10.1167/iovs.07-1355] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
PURPOSE The authors investigated the contributions of the transient receptor potential vanilloid-1 receptor (TRPV1) and Ca(2+) to microglial IL-6 and nuclear factor kappa B (NFkappaB) translocation with elevated hydrostatic pressure. METHODS The authors first examined IL-6 colocalization with the microglia marker Iba-1 in the DBA/2 mouse model of glaucoma to establish relevance. They isolated microglia from rat retina and maintained them at ambient or elevated (+70 mm Hg) hydrostatic pressure in vitro and used ELISA and immunocytochemistry to measure changes in the IL-6 concentration and NFkappaB translocation induced by the Ca(2+) chelator EGTA, the broad-spectrum Ca(2+) channel inhibitor ruthenium red, and the TRPV1 antagonist iodo-resiniferatoxin (I-RTX). They applied the Ca(2+) dye Fluo-4 AM to measure changes in intracellular Ca(2+) at elevated pressure induced by I-RTX and confirmed TRPV1 expression in microglia using PCR and immunocytochemistry. RESULTS In DBA/2 retina, elevated intraocular pressure increased microglial IL-6 in the ganglion cell layer. Elevated hydrostatic pressure (24 hours) increased microglial IL-6 release, cytosolic NFkappaB, and NFkappaB translocation in vitro. These effects were reduced substantially by EGTA and ruthenium red. Antagonism of TRPV1 in microglia partially inhibited pressure-induced increases in IL-6 release and NFkappaB translocation. Brief elevated pressure (1 hour) induced a significant increase in microglial intracellular Ca(2+) that was partially attenuated by TRPV1 antagonism. CONCLUSIONS Elevated pressure induces an influx of extracellular Ca(2+) in retinal microglia that precedes the activation of NFkappaB and the subsequent production and release of IL-6 and is at least partially dependent on the activation of TRPV1 and other ruthenium red-sensitive channels.
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Affiliation(s)
- Rebecca M Sappington
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0654, USA
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