251
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Nicotra L, Tuke J, Grace PM, Rolan PE, Hutchinson MR. Sex differences in mechanical allodynia: how can it be preclinically quantified and analyzed? Front Behav Neurosci 2014; 8:40. [PMID: 24592221 PMCID: PMC3923156 DOI: 10.3389/fnbeh.2014.00040] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 01/27/2014] [Indexed: 11/18/2022] Open
Abstract
Translating promising preclinical drug discoveries to successful clinical trials remains a significant hurdle in pain research. Although animal models have significantly contributed to understanding chronic pain pathophysiology, the majority of research has focused on male rodents using testing procedures that produce sex difference data that do not align well with comparable clinical experiences. Additionally, the use of animal pain models presents ongoing ethical challenges demanding continuing refinement of preclinical methods. To this end, this study sought to test a quantitative allodynia assessment technique and associated statistical analysis in a modified graded nerve injury pain model with the aim to further examine sex differences in allodynia. Graded allodynia was established in male and female Sprague Dawley rats by altering the number of sutures placed around the sciatic nerve and quantified by the von Frey test. Linear mixed effects modeling regressed response on each fixed effect (sex, oestrus cycle, pain treatment). On comparison with other common von Frey assessment techniques, utilizing lower threshold filaments than those ordinarily tested, at 1 s intervals, appropriately and successfully investigated female mechanical allodynia, revealing significant sex and oestrus cycle difference across the graded allodynia that other common behavioral methods were unable to detect. Utilizing this different von Frey approach and graded allodynia model, a single suture inflicting less allodynia was sufficient to demonstrate exaggerated female mechanical allodynia throughout the phases of dioestrus and pro-oestrus. Refining the von Frey testing method, statistical analysis technique and the use of a graded model of chronic pain, allowed for examination of the influences on female mechanical nociception that other von Frey methods cannot provide.
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Affiliation(s)
- Lauren Nicotra
- Department of Pharmacology, Neuroimmunopharmacology, The University of Adelaide Adelaide, SA, Australia
| | - Jonathan Tuke
- Faculty of Engineering, School of Mathematical Sciences, Computer Science and Mathematics, The University of Adelaide Adelaide, SA, Australia
| | - Peter M Grace
- Department of Psychology and Neuroscience, The University of Colorado Boulder, CO, USA
| | - Paul E Rolan
- Department of Pharmacology, Neuroimmunopharmacology, The University of Adelaide Adelaide, SA, Australia
| | - Mark R Hutchinson
- Department of Physiology, Neuroimmunopharmacology, The University of Adelaide Adelaide, SA, Australia
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252
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Potokar M, Korva M, Jorgačevski J, Avšič-Županc T, Zorec R. Tick-borne encephalitis virus infects rat astrocytes but does not affect their viability. PLoS One 2014; 9:e86219. [PMID: 24465969 PMCID: PMC3896472 DOI: 10.1371/journal.pone.0086219] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 12/11/2013] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) causes one of the most dangerous human neuroinfections in Europe and Asia. To infect neurons it must cross the blood-brain-barrier (BBB), and presumably also cells adjacent to the BBB, such as astrocytes, the most abundant glial cell type. However, the knowledge about the viral infection of glial cells is fragmental. Here we studied whether TBEV infects rat astrocytes. Rats belong to an animal group serving as a TBEV amplifying host. We employed high resolution quantitative fluorescence microscopy to investigate cell entry and cytoplasmic mobility of TBEV particles along with the effect on the cell cytoskeleton and cell survival. We report that infection of astrocytes with TBEV increases with time of exposure to TBEV and that with post-infection time TBEV particles gained higher mobility. After several days of infection actin cytoskeleton was affected, but cell survival was unchanged, indicating that rat astrocytes resist TBEV-mediated cell death, as reported for other mammalian cells. Therefore, astrocytes may present an important pool of dormant TBEV infections and a new target for therapeutic intervention.
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Affiliation(s)
- Maja Potokar
- Celica Biomedical Center, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Miša Korva
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jernej Jorgačevski
- Celica Biomedical Center, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tatjana Avšič-Županc
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Robert Zorec
- Celica Biomedical Center, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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253
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Schubert P, Ferroni S. Pathological glial reactions in neurodegenerative disorders: prospects for future therapeutics. Expert Rev Neurother 2014. [DOI: 10.1586/14737175.3.3.279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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254
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Human cytomegalovirus infection modulates thrombospondins 1 and 2 in primary fetal astrocytes. Neuroreport 2014; 24:526-35. [PMID: 23660684 DOI: 10.1097/wnr.0b013e32836206d1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Transmission of human cytomegalovirus (HCMV) to the fetus is the most common type of intrauterine infection; the mechanism of HCMV pathogenesis in the developing central nervous system remains unclear. Thrombospondins 1 and 2 (TSP1, TSP2) produced by immature astrocytes are critical for fetal synaptogenesis. To examine the effect of HCMV on fetal astrocytes, human fetal astrocytes were isolated and cultured with HCMV AD169. Cells were harvested at different time points. Protein and mRNA expressions of TSP1 and TSP2 were determined using RT-qPCR, western blotting analysis, and enzyme-linked immunosorbent assay. The results showed that HCMV infection induced time-dependent decreases in mRNA and protein expressions of both TSP1 and TSP2 in astrocytes. Flow cytometry was used to detect apoptosis of HCMV-infected astrocytes, and the result indicated that there was no linkage between cell apoptosis and the decrease in TSP1 and TSP2 expressions induced by HCMV infection. When ganciclovir treatment was performed on HCMV-infected astrocytes, results showed that ganciclovir treatment inhibited the reduction of TSP1 and TSP2 expression in astrocytes. In the further study, pEGFP-N3-IE1 was transfected into astrocytes to identify that it was not IE1 but active viral replication that was essential in the continuous decrease of TSP1 and TSP2 expressions in HCMV-infected astrocytes.
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255
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Madhusoodanan S, Danan D, Moise D. Psychiatric manifestations of brain tumors: diagnostic implications. Expert Rev Neurother 2014; 7:343-9. [PMID: 17425489 DOI: 10.1586/14737175.7.4.343] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Brain tumors can cause any type of psychiatric symptoms. Rarely, brain tumors can present without any localizing signs but with psychiatric symptoms. A review of the literature indicates that there is no association between psychiatric symptoms and tumor location or histological type. Hence, it is important for clinicians to have an index of suspicion of brain tumor in patients with new-onset psychiatric symptoms, atypical presentations and treatment resistance and, as a result, consider neuroimaging. Early detection is of paramount importance for treatment and quality of life of patients. Mood symptoms may herald a brain tumor. For example, anorexia can be a presenting symptom of hypothalamic tumors. A prospective controlled study will be of benefit to further assess the association between psychiatric symptoms and brain tumor locations. New developments in the diagnostic and treatment area of brain tumors would be of help in undertaking such a prospective study.
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256
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Vardjan N, Kreft M, Zorec R. Regulated Exocytosis in Astrocytes is as Slow as the Metabolic Availability of Gliotransmitters: Focus on Glutamate and ATP. GLUTAMATE AND ATP AT THE INTERFACE OF METABOLISM AND SIGNALING IN THE BRAIN 2014; 11:81-101. [DOI: 10.1007/978-3-319-08894-5_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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257
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Abstract
Chemical synapses allow neurons to perform complex computations and regulate other systems of the body. At a chemical synapse, pre- and postsynaptic sites are separated by a small space (the synaptic cleft) and surrounded by astrocytes. The basement membrane (BM), a sheetlike, specialized extracellular matrix (ECM), is found ubiquitously in the PNS. It has become clear that the ECMs not only play a structural role but also serve as barriers and filters in the PNS and CNS. Moreover, proteoglycans and tenascin family proteins in the ECM regulate synapse formation and synaptic plasticity. Although CNS synapses lack the BMs, recent results indicate that the BM-associated collagens are also present in the CNS synaptic cleft and affect synaptogenesis in both the CNS and the PNS. The C1q domain-containing family proteins are important components of the CNS synaptic cleft in regulating synapse formation, maintenance, and the pruning process. The ECM is regarded as a crucial component of the tetrapartite synapse, consisting of pre- and postsynaptic neurons, astrocyte, and ECM.
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Affiliation(s)
- Anne Heikkinen
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Taina Pihlajaniemi
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University, Bochum, Germany
| | - Michisuke Yuzaki
- Department of Physiology, School of Medicine, Keio University, Tokyo, Japan.
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258
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The "memory kinases": roles of PKC isoforms in signal processing and memory formation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 122:31-59. [PMID: 24484697 DOI: 10.1016/b978-0-12-420170-5.00002-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The protein kinase C (PKC) isoforms, which play an essential role in transmembrane signal conduction, can be viewed as a family of "memory kinases." Evidence is emerging that they are critically involved in memory acquisition and maintenance, in addition to their involvement in other functions of cells. Deficits in PKC signal cascades in neurons are one of the earliest abnormalities in the brains of patients suffering from Alzheimer's disease. Their dysfunction is also involved in several other types of memory impairments, including those related to emotion, mental retardation, brain injury, and vascular dementia/ischemic stroke. Inhibition of PKC activity leads to a reduced capacity of many types of learning and memory, but may have therapeutic values in treating substance abuse or aversive memories. PKC activators, on the other hand, have been shown to possess memory-enhancing and antidementia actions. PKC pharmacology may, therefore, represent an attractive area for developing effective cognitive drugs for the treatment of many types of memory disorders and dementias.
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259
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Noori HR. Examples of Hysteresis Phenomena in Biology. SPRINGERBRIEFS IN APPLIED SCIENCES AND TECHNOLOGY 2014. [DOI: 10.1007/978-3-642-38218-5_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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260
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Xu G, Wang W, Zhou M. Spatial organization of NG2 glial cells and astrocytes in rat hippocampal CA1 region. Hippocampus 2013; 24:383-95. [PMID: 24339242 DOI: 10.1002/hipo.22232] [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: 08/10/2013] [Revised: 10/31/2013] [Accepted: 11/26/2013] [Indexed: 12/12/2022]
Abstract
Similar to astrocytes, NG2 glial cells are uniformly distributed in the central nervous system (CNS). However, little is known about the interspatial relationship, nor the functional interactions between these two star-shaped glial subtypes. Confocal morphometric analysis showed that NG2 immunostained cells are spatially organized as domains in rat hippocampal CA1 region and that each NG2 glial domain occupies a spatial volume of ∼178, 364 μm(3) . The processes of NG2 glia and astrocytes overlap extensively; each NG2 glial domain interlaces with the processes deriving from 5.8 ± 0.4 neighboring astrocytes, while each astrocytic domain accommodates processes stemming from 4.5 ± 0.3 abutting NG2 glia. In CA1 stratum radiatum, the cell bodies of morphologically identified glial cells often appear to make direct somatic-somata contact, termed as doublets. We used dual patch recording and postrecording NG2/GFAP double staining to determine the glial identities of these doublets. We show that among 44 doublets, 50% were NG2 glia-astrocyte pairs, while another 38.6% and 11.4% were astrocyte-astrocyte and NG2 glia-NG2 glia pairs, respectively. In dual patch recording, neither electrical coupling nor intercellular biocytin transfer was detected in astrocyte-NG2 glia or NG2 glia-NG2 glia doublets. Altogether, although NG2 glia and astrocytes are not gap junction coupled, their cell bodies and processes are interwoven extensively. The anatomical and physiological relationships revealed in this study should facilitate future studies to understand the metabolic coupling and functional communication between NG2 glia and astrocytes.
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Affiliation(s)
- Guangjin Xu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
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261
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Salamone A, Mura E, Zappettini S, Grilli M, Olivero G, Preda S, Govoni S, Marchi M. Inhibitory effects of beta-amyloid on the nicotinic receptors which stimulate glutamate release in rat hippocampus: the glial contribution. Eur J Pharmacol 2013; 723:314-21. [PMID: 24275353 DOI: 10.1016/j.ejphar.2013.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/22/2013] [Accepted: 11/11/2013] [Indexed: 01/20/2023]
Abstract
We investigated on the neuronal nicotinic acetylcholine receptor subtypes involved in the cholinergic control of in vivo hippocampal glutamate (GLU), aspartate (ASP) and inhibitory γ-aminobutyric acid (GABA) overflow. We also investigated on the possible contribution of nicotinic acetylcholine receptors subtypes present on astrocytes in the regulation of the three neurotransmitter amino acids overflow using hippocampal gliosomes and on the effects of beta-amyloid (Aβ) 1-40 on the nicotinic control of amino acid neurotransmitter release. Nicotine was able to enhance the in vivo overflow of the three amino acids being more potent in stimulating GLU overflow. The α7 selective agonist PHA543613 induced an overflow very similar to that of nicotine. The α4β2 selective agonist 5IA85380 was significantly less potent in inducing GLU overflow while the overflow of ASP and GABA were almost inconsistent. Aβ1-40 inhibited the neurotransmitter overflow stimulated by PHA543613 but not the one evoked by 5IA85380. In hippocampal gliosomes nicotine elicited selectively GLU overflow which was also evoked by 5IA85380 and by the α7 selective agonist choline. Nicotine- and choline-induced glutamate overflow in gliosomes was inhibited by Aα1-40. In conclusion nicotine administration in vivo elicits hippocampal GLU release mostly through α7 nicotinic acetylcholine receptors likely present both on neurons and astrocytes. Aβ inhibitory effect on the nicotinic-control of GLU release seems to depend primarily to the inhibition of α7 nicotinic acetylcholine receptors functional responses.
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Affiliation(s)
- Alessia Salamone
- Section of Pharmacology and Toxicology, Department of Pharmacy, University of Genoa, Genoa, Italy
| | - Elisa Mura
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
| | - Stefania Zappettini
- Section of Pharmacology and Toxicology, Department of Pharmacy, University of Genoa, Genoa, Italy
| | - Massimo Grilli
- Section of Pharmacology and Toxicology, Department of Pharmacy, University of Genoa, Genoa, Italy
| | - Guendalina Olivero
- Section of Pharmacology and Toxicology, Department of Pharmacy, University of Genoa, Genoa, Italy
| | - Stefania Preda
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
| | - Stefano Govoni
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
| | - Mario Marchi
- Section of Pharmacology and Toxicology, Department of Pharmacy, University of Genoa, Genoa, Italy; Center of Excellence for Biomedical Research, University of Genoa, Italy.
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262
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Asea A, Kaur P, Panossian A, Wikman KG. Evaluation of molecular chaperons Hsp72 and neuropeptide Y as characteristic markers of adaptogenic activity of plant extracts. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2013; 20:1323-1329. [PMID: 23920279 DOI: 10.1016/j.phymed.2013.07.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 05/28/2013] [Accepted: 07/02/2013] [Indexed: 06/02/2023]
Abstract
We have previously demonstrated that ADAPT-232, a fixed combination of adaptogenic substances derived from Eleutherococcus senticosus root extract, Schisandra chinensis berry extract, Rhodiola rosea root extract stimulated the expression and release of neuropeptide Y (NPY) and molecular chaperone Hsp72 from isolated human neurolgia cells. Both of these mediators of stress response are known to play an important role in regulation of neuroendocrine system and immune response. We further demonstrated that ADAPT-232 induced release of Hsp70 is mediated by NPY, suggesting an existence of NPY-mediated pathway of activation of Hsp72 release into the blood circulation system. The objective of this study was to determine whether this pathway is common for adaptogens and whether NPY and/or Hsp72 can be considered as necessary specific biomarkers for adaptogenic activity. The release of NPY and Hsp72 from neuroglia cells in response to treatment with various plant extracts (n=23) including selected validated adaptogens, partly validated adaptogens, claimed but negligibly validated adaptogens and some other plant extracts affecting neuroendocrine and immune systems but never considered as adaptogens was measured using high throughput ELISA techniques. We demonstrated that adaptogens, e.g. R. rosea, S. chinensis and E. senticosus stimulate both NPY and Hsp70 release from neuroblastoma cells, while tonics and stimulants have no significant effect on NPY in this in vitro test. In the groups of partly validated adaptogens the effect of Panax ginseng and Withania somnifera was not statistically significant both on NPY and Hsp70 release, while the activating effect of Bryonia alba and Rhaponticum cartamoides was significant only on Hsp70. In contrast, all tested non-adaptogens, such as antiinflammatoty plant extracts Matricaria recutita, Pelargonium sidoides, Hedera helix and Vitis vinifera significantly inhibit Hsp70 release and have no influence on NPY release from neuroblastoma cells. These experiments were further validated using primary human neurons and confirmed that adaptogens activate the release of both NPY and Hsp70, while tested non adaptogens were inactive in NPY assay and inhibit the release of Hsp70. Taken together, our data demonstrates for the first time that neuropeptide Y and heat shock protein Hsp70 can be used as molecular biomarkers for adaptogenic activity.
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Affiliation(s)
- Alexzander Asea
- Morehouse School of Medicine, Department of Microbiology, Biochemistry and Immunology & Department of Pathology and Laboratory Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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263
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Won KA, Kim MJ, Yang KY, Park JS, Lee MK, Park MK, Bae YC, Ahn DK. The glial-neuronal GRK2 pathway participates in the development of trigeminal neuropathic pain in rats. THE JOURNAL OF PAIN 2013; 15:250-61. [PMID: 24216329 DOI: 10.1016/j.jpain.2013.10.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 09/23/2013] [Accepted: 10/31/2013] [Indexed: 10/26/2022]
Abstract
UNLABELLED This study examined the role of the glial-neuronal G protein-coupled receptor kinase 2 (GRK2) pathway in the development of trigeminal neuropathic pain. Male Sprague Dawley rats, weighing 220 to 240 g, were anesthetized with ketamine (0.2 g/kg) and xylazine (0.02 g/kg). Under anesthesia, the left lower second molar was extracted, followed by the placement of a mini-dental implant to intentionally injure the inferior alveolar nerve. This injury produced mechanical allodynia along with the downregulation of neuronal GRK2 expression in the medullary dorsal horn. On the other hand, early intracisternal treatment with MDL28170, a calpain inhibitor, produced prolonged antiallodynic effects and blocked this downregulation of neuronal GRK2 expression. The intracisternal infusion of minocycline, a microglia inhibitor, and l-α-aminoadipic acid, an astrocytic specific inhibitor, also blocked the induced mechanical allodynia and downregulated neuronal GRK2 expression, respectively. Double immunofluorescence showed that the interleukin (IL)-1β and IL-1R signals colocalize with the astrocytes and neurons, respectively, in the medullary dorsal horn following an inferior alveolar nerve injury. In addition, the intracisternal infusion of an IL-1 receptor antagonist also produced antiallodynic effects and blocked the downregulation of neuronal GRK2 expression. These results suggest that the glial-neuronal GRK2 pathway is a potentially important new target for treating neuropathic pain. Moreover, the IL-1β expressed in astrocytes plays a significant role in modulating this pathway. PERSPECTIVE This study showed that the glial-neuronal GRK2 pathway participates in the development of trigeminal neuropathic pain in rats. These results suggest that the glial-neuronal GRK2 pathway is a potentially important new target for the treatment of neuropathic pain.
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Affiliation(s)
- Kyoung A Won
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Min J Kim
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Kui Y Yang
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Jae S Park
- Department of Physiology, School of Medicine, Kyungpook National University Daegu, Daegu, Korea
| | - Min K Lee
- Department of Dental Hygiene, Dong-Eui University, Busan, Korea
| | - Min K Park
- Department of Dental Hygiene, Kyung-Woon University, Gumi, Korea
| | - Yong C Bae
- Department of Oral Anatomy, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Dong K Ahn
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu, Korea.
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264
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Harada S, Nakamoto K, Tokuyama S. The involvement of midbrain astrocyte in the development of morphine tolerance. Life Sci 2013; 93:573-8. [DOI: 10.1016/j.lfs.2013.08.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/02/2013] [Accepted: 08/13/2013] [Indexed: 01/28/2023]
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265
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Liu Y, Li C. Stochastic resonance in feedforward-loop neuronal network motifs in astrocyte field. J Theor Biol 2013; 335:265-75. [DOI: 10.1016/j.jtbi.2013.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/02/2013] [Accepted: 07/07/2013] [Indexed: 10/26/2022]
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266
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VanElzakker MB. Chronic fatigue syndrome from vagus nerve infection: A psychoneuroimmunological hypothesis. Med Hypotheses 2013; 81:414-23. [DOI: 10.1016/j.mehy.2013.05.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 05/15/2013] [Accepted: 05/23/2013] [Indexed: 12/20/2022]
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267
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Abstract
Astrocytes are the predominant glial cell type in the CNS. Although astrocytes are electrically nonexcitable, their excitability is manifested by their Ca2+ signaling, which serves as a mediator of neuron-glia bidirectional interactions via tripartite synapses. Studies from in vivo two-photon imaging indicate that in healthy animals, the properties of spontaneous astrocytic Ca2+ signaling are affected by animal species, age, wakefulness and the location of astrocytes in the brain. Intercellular Ca2+ waves in astrocytes can be evoked by a variety of stimulations. In animal models of some brain disorders, astrocytes can exhibit enhanced Ca2+ excitability featured as regenerative intercellular Ca2+ waves. This review first briefly summarizes the astrocytic Ca2+ signaling pathway and the procedure of in vivo two-photon Ca2+ imaging of astrocytes. It subsequently summarizes in vivo astrocytic Ca2+ signaling in health and brain disorders from experimental studies of animal models, and discusses the possible mechanisms and therapeutic implications underlying the enhanced Ca2+ excitability in astrocytes in brain disorders. Finally, this review summarizes molecular genetic approaches used to selectively manipulate astrocyte function in vivo and their applications to study the role of astrocytes in synaptic plasticity and brain disorders.
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Affiliation(s)
- Shinghua Ding
- Dalton Cardiovascular Research Center, Department of Biological Engineering, University of Missouri, Columbia, MO 65211, USA
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268
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TRPA1 channels are regulators of astrocyte basal calcium levels and long-term potentiation via constitutive D-serine release. J Neurosci 2013; 33:10143-53. [PMID: 23761909 DOI: 10.1523/jneurosci.5779-12.2013] [Citation(s) in RCA: 233] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Astrocytes are found throughout the brain where they make extensive contacts with neurons and synapses. Astrocytes are known to display intracellular Ca(2+) signals and release signaling molecules such as D-serine into the extracellular space. However, the role(s) of astrocyte Ca(2+) signals in hippocampal long-term potentiation (LTP), a form of synaptic plasticity involved in learning and memory, remains unclear. Here, we explored a recently discovered novel TRPA1 channel-mediated transmembrane Ca(2+) flux pathway in astrocytes. Specifically, we determined whether block or genetic deletion of TRPA1 channels affected LTP of Schaffer collateral to CA1 pyramidal neuron synapses. Using pharmacology, TRPA1(-/-) mice, imaging, electrophysiology, and D-serine biosensors, our data indicate that astrocyte TRPA1 channels contribute to basal Ca(2+) levels and are required for constitutive D-serine release into the extracellular space, which contributes to NMDA receptor-dependent LTP. The findings have broad relevance for the study of astrocyte-neuron interactions by demonstrating how TRPA1 channel-mediated fluxes contribute to astrocyte basal Ca(2+) levels and neuronal function via constitutive D-serine release.
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269
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Immune privilege as an intrinsic CNS property: astrocytes protect the CNS against T-cell-mediated neuroinflammation. Mediators Inflamm 2013; 2013:320519. [PMID: 24023412 PMCID: PMC3760105 DOI: 10.1155/2013/320519] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 07/09/2013] [Indexed: 12/26/2022] Open
Abstract
Astrocytes have many functions in the central nervous system (CNS). They support differentiation and homeostasis of neurons and influence synaptic activity. They are responsible for formation of the blood-brain barrier (BBB) and make up the glia limitans. Here, we review their contribution to neuroimmune interactions and in particular to those induced by the invasion of activated T cells. We discuss the mechanisms by which astrocytes regulate pro- and anti-inflammatory aspects of T-cell responses within the CNS. Depending on the microenvironment, they may become potent antigen-presenting cells for T cells and they may contribute to inflammatory processes. They are also able to abrogate or reprogram T-cell responses by inducing apoptosis or secreting inhibitory mediators. We consider apparently contradictory functions of astrocytes in health and disease, particularly in their interaction with lymphocytes, which may either aggravate or suppress neuroinflammation.
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270
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Primary hippocampal neurons, which lack four crucial extracellular matrix molecules, display abnormalities of synaptic structure and function and severe deficits in perineuronal net formation. J Neurosci 2013; 33:7742-55. [PMID: 23637166 DOI: 10.1523/jneurosci.3275-12.2013] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The extracellular matrix (ECM) of the brain plays crucial roles during the development, maturation, and regeneration of the CNS. In a subpopulation of neurons, the ECM condenses to superstructures called perineuronal nets (PNNs) that surround synapses. Camillo Golgi described PNNs a century ago, yet their biological functions remain elusive. Here, we studied a mouse mutant that lacks four ECM components highly enriched in the developing brain: the glycoproteins tenascin-C and tenascin-R and the chondroitin sulfate proteoglycans brevican and neurocan. Primary embryonic hippocampal neurons and astrocytes were cultivated using a cell insert system that allows for co-culture of distinct cell populations in the absence of direct membrane contacts. The wild-type and knock-out cells were combined in the four possible permutations. Using this approach, neurons cultivated in the presence of mutant astrocytes displayed a transient increase of synapses after 2 weeks. However, after a period of 3 weeks or longer, synapse formation and stabilization were compromised when either neuron or astrocyte cell populations or both were of mutant origin. The development of PNN structures was observed, but their size was substantially reduced on knock-out neurons. The synaptic activity of both wild-type and knock-out neurons was monitored using whole-cell patch clamping. The salient observation was a reduced frequency of IPSCs and EPSCs, whereas the amplitudes were not modified. Remarkably, the knock-out neuron phenotypes could not be rescued by wild-type astrocytes. We conclude that the elimination of four ECM genes compromises neuronal function.
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271
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Yoshizawa K, Narita M, Suzuki T. [Psychological dependence on opioid analgesics]. Nihon Yakurigaku Zasshi 2013; 142:22-27. [PMID: 23842224 DOI: 10.1254/fpj.142.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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272
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Potokar M, Vardjan N, Stenovec M, Gabrijel M, Trkov S, Jorgačevski J, Kreft M, Zorec R. Astrocytic vesicle mobility in health and disease. Int J Mol Sci 2013; 14:11238-58. [PMID: 23712361 PMCID: PMC3709730 DOI: 10.3390/ijms140611238] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 04/26/2013] [Accepted: 05/08/2013] [Indexed: 12/14/2022] Open
Abstract
Astrocytes are no longer considered subservient to neurons, and are, instead, now understood to play an active role in brain signaling. The intercellular communication of astrocytes with neurons and other non-neuronal cells involves the exchange of molecules by exocytotic and endocytotic processes through the trafficking of intracellular vesicles. Recent studies of single vesicle mobility in astrocytes have prompted new views of how astrocytes contribute to information processing in nervous tissue. Here, we review the trafficking of several types of membrane-bound vesicles that are specifically involved in the processes of (i) intercellular communication by gliotransmitters (glutamate, adenosine 5′-triphosphate, atrial natriuretic peptide), (ii) plasma membrane exchange of transporters and receptors (EAAT2, MHC-II), and (iii) the involvement of vesicle mobility carrying aquaporins (AQP4) in water homeostasis. The properties of vesicle traffic in astrocytes are discussed in respect to networking with neighboring cells in physiologic and pathologic conditions, such as amyotrophic lateral sclerosis, multiple sclerosis, and states in which astrocytes contribute to neuroinflammatory conditions.
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Affiliation(s)
- Maja Potokar
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Matjaž Stenovec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Mateja Gabrijel
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Saša Trkov
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Marko Kreft
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
- Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; E-Mails: (M.P.); (N.V.); (M.S.); (M.G.); (S.T.); (J.J.); (M.K.)
- Celica Biomedical Center, Tehnološki park 24, 1000 Ljubljana, Slovenia
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +386-1543-7020; Fax: +386-1543-7036
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273
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Dong QP, He JQ, Chai Z. Astrocytic Ca(2+) waves mediate activation of extrasynaptic NMDA receptors in hippocampal neurons to aggravate brain damage during ischemia. Neurobiol Dis 2013; 58:68-75. [PMID: 23702310 DOI: 10.1016/j.nbd.2013.05.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/22/2013] [Accepted: 05/10/2013] [Indexed: 10/26/2022] Open
Abstract
Excitotoxicity plays a central role in the neuronal damage during ischemic stroke. Although growing evidence suggests that activation of extrasynaptic NMDA receptors initiates neuronal death, no direct evidence demonstrated their activation during ischemia. Using rat hippocampal slices, we detected oxygen-glucose deprivation (OGD) induced slow inward currents (SICs) mediated by extrasynaptic NMDA receptors in CA1 pyramidal neurons. Moreover, Ca(2+) chelator BAPTA dialysis into astrocytic network decreased the frequency of OGD induced SICs, indicating that the activation of extrasynaptic NMDA receptors depended on astrocytic Ca(2+) activity. To further demonstrate the importance of astrocytic Ca(2+) activity, we tested hippocampal slices from inositol triphosphate receptor type 2 (IP3R2) knock-out mice which abolished the astrocytic Ca(2+) activity. As expected, the frequency of OGD induced SICs was reduced. Using two-photon Ca(2+) imaging, we characterized the astrocytic Ca(2+) dynamics. By controlling Ca(2+) level in the individual astrocytes using targeted photolysis, we found that OGD facilitated the propagation of intercellular Ca(2+) waves, which were inhibited by gap junction blocker carbenoxolone (CBX). CBX also inhibited the Ca(2+) activity of the astrocytic network and decreased the SIC frequency during OGD. Functionally, the infarct volumes from brain ischemia were reduced in IP3R2 knock-out mice and in rat intracerebrally delivered with CBX. Our results demonstrate that enhanced Ca(2+) activity of the astrocytic network plays a key role on the activation of extrasynaptic NMDA receptors in hippocampal neurons, which enhances brain damage during ischemia.
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Affiliation(s)
- Qi-Ping Dong
- College of Life Sciences, Peking University, Beijing, China
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274
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Tang X, Zhou L, Wagner AM, Marchetto MCN, Muotri AR, Gage FH, Chen G. Astroglial cells regulate the developmental timeline of human neurons differentiated from induced pluripotent stem cells. Stem Cell Res 2013; 11:743-57. [PMID: 23759711 DOI: 10.1016/j.scr.2013.05.002] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 03/28/2013] [Accepted: 05/07/2013] [Indexed: 02/03/2023] Open
Abstract
Neurons derived from human induced-pluripotent stem cells (hiPSCs) have been used to model a variety of neurological disorders. Different protocols have been used to differentiate hiPSCs into neurons, but their functional maturation process has varied greatly among different studies. Here, we demonstrate that laminin, a commonly used substrate for iPSC cultures, was inefficient to promote fully functional maturation of hiPSC-derived neurons. In contrast, astroglial substrate greatly accelerated neurodevelopmental processes of hiPSC-derived neurons. We have monitored the neural differentiation and maturation process for up to two months after plating hiPSC-derived neuroprogenitor cells (hNPCs) on laminin or astrocytes. We found that one week after plating hNPCs, there were 21-fold more newly differentiated neurons on astrocytes than on laminin. Two weeks after plating hNPCs, there were 12-fold more dendritic branches in neurons cultured on astrocytes than on laminin. Six weeks after plating hNPCs, the Na(+) and K(+) currents, as well as glutamate and GABA receptor currents, were 3-fold larger in neurons cultured on astrocytes than on laminin. And two months after plating hNPCs, the spontaneous synaptic events were 8-fold more in neurons cultured on astrocytes than on laminin. These results highlight a critical role of astrocytes in promoting neural differentiation and functional maturation of human neurons derived from hiPSCs. Moreover, our data presents a thorough developmental timeline of hiPSC-derived neurons in culture, providing important benchmarks for future studies on disease modeling and drug screening.
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Affiliation(s)
- Xin Tang
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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275
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Shigetomi E, Bushong EA, Haustein MD, Tong X, Jackson-Weaver O, Kracun S, Xu J, Sofroniew MV, Ellisman MH, Khakh BS. Imaging calcium microdomains within entire astrocyte territories and endfeet with GCaMPs expressed using adeno-associated viruses. J Gen Physiol 2013; 141:633-47. [PMID: 23589582 PMCID: PMC3639581 DOI: 10.1085/jgp.201210949] [Citation(s) in RCA: 264] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/18/2013] [Indexed: 11/20/2022] Open
Abstract
Intracellular Ca(2+) transients are considered a primary signal by which astrocytes interact with neurons and blood vessels. With existing commonly used methods, Ca(2+) has been studied only within astrocyte somata and thick branches, leaving the distal fine branchlets and endfeet that are most proximate to neuronal synapses and blood vessels largely unexplored. Here, using cytosolic and membrane-tethered forms of genetically encoded Ca(2+) indicators (GECIs; cyto-GCaMP3 and Lck-GCaMP3), we report well-characterized approaches that overcome these limitations. We used in vivo microinjections of adeno-associated viruses to express GECIs in astrocytes and studied Ca(2+) signals in acute hippocampal slices in vitro from adult mice (aged ∼P80) two weeks after infection. Our data reveal a sparkling panorama of unexpectedly numerous, frequent, equivalently scaled, and highly localized Ca(2+) microdomains within entire astrocyte territories in situ within acute hippocampal slices, consistent with the distribution of perisynaptic branchlets described using electron microscopy. Signals from endfeet were revealed with particular clarity. The tools and experimental approaches we describe in detail allow for the systematic study of Ca(2+) signals within entire astrocytes, including within fine perisynaptic branchlets and vessel-associated endfeet, permitting rigorous evaluation of how astrocytes contribute to brain function.
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Affiliation(s)
- Eiji Shigetomi
- Department of Physiology and 2 Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
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276
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Hopkins SC, Heffernan MLR, Saraswat LD, Bowen CA, Melnick L, Hardy LW, Orsini MA, Allen MS, Koch P, Spear KL, Foglesong RJ, Soukri M, Chytil M, Fang QK, Jones SW, Varney MA, Panatier A, Oliet SHR, Pollegioni L, Piubelli L, Molla G, Nardini M, Large TH. Structural, Kinetic, and Pharmacodynamic Mechanisms of d-Amino Acid Oxidase Inhibition by Small Molecules. J Med Chem 2013; 56:3710-24. [DOI: 10.1021/jm4002583] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Seth C. Hopkins
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | | | - Lakshmi D. Saraswat
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Carrie A. Bowen
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Laurence Melnick
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Larry W. Hardy
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Michael A. Orsini
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | | | - Patrick Koch
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Kerry L. Spear
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | | | | | - Milan Chytil
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Q. Kevin Fang
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Steven W. Jones
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Mark A. Varney
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
| | - Aude Panatier
- Neurocentre Magendie, Inserm U862 and Université de Bordeaux, Bordeaux, F-33077, France
| | - Stephane H. R. Oliet
- Neurocentre Magendie, Inserm U862 and Université de Bordeaux, Bordeaux, F-33077, France
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie
e Scienze della Vita, Università degli Studi dell’Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
- The Protein Factory, Politecnico di Milano, ICRM-CNR and Università degli Studi dell’Insubria, Via Mancinelli 7,
20131 Milano, Italy
| | - Luciano Piubelli
- Dipartimento di Biotecnologie
e Scienze della Vita, Università degli Studi dell’Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
- The Protein Factory, Politecnico di Milano, ICRM-CNR and Università degli Studi dell’Insubria, Via Mancinelli 7,
20131 Milano, Italy
| | - Gianluca Molla
- Dipartimento di Biotecnologie
e Scienze della Vita, Università degli Studi dell’Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
- The Protein Factory, Politecnico di Milano, ICRM-CNR and Università degli Studi dell’Insubria, Via Mancinelli 7,
20131 Milano, Italy
| | - Marco Nardini
- Department of Biosciences, University of Milan, I-20133 Milano, Italy
| | - Thomas H. Large
- Sunovion Pharmaceuticals Inc., Marlborough, Massachusetts 01752, United States
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277
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Inhibition of a SNARE-sensitive pathway in astrocytes attenuates damage following stroke. J Neurosci 2013; 33:4234-40. [PMID: 23467341 DOI: 10.1523/jneurosci.5495-12.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A strong body of research has defined the role of excitotoxic glutamate in animal models of brain ischemia and stroke; however, clinical trials of glutamate receptor antagonists have demonstrated their limited capacity to prevent brain damage following ischemia. We propose that astrocyte-neuron signaling represents an important modulatory target that may be useful in mediating damage following stroke. To assess the impact of astrocyte signaling on damage following stroke, we have used the astrocyte-specific dominant-negative SNARE mouse model (dnSNARE). Recent findings have shown that the astrocytic SNARE signaling pathway can affect neuronal excitability by regulating the surface expression of NMDA receptors. Using focal photothrombosis via the Rose Bengal method, as well as excitotoxic NMDA lesions, we show that dnSNARE animals exhibited a sparing of damaged tissue quantified using Nissl and NeuN staining. At the same time point, animals were also tested in behavioral tasks that probe the functional integrity of stroke- or lesion-damaged motor and somatosensory areas. We found that dnSNARE mice performed significantly better than littermate controls on rung walk and adhesive dot removal tasks following lesion. Together, our results demonstrate the important role of astrocytic signaling under ischemic conditions. Drugs targeting astrocyte signaling have a potential benefit for the outcome of stroke in human patients by limiting the spread of damage.
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278
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Todd GK, Boosalis CA, Burzycki AA, Steinman MQ, Hester LD, Shuster PW, Patterson RL. Towards neuronal organoids: a method for long-term culturing of high-density hippocampal neurons. PLoS One 2013; 8:e58996. [PMID: 23634200 PMCID: PMC3636240 DOI: 10.1371/journal.pone.0058996] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 02/08/2013] [Indexed: 11/19/2022] Open
Abstract
One of the goals in neuroscience is to obtain tractable laboratory cultures that closely recapitulate in vivo systems while still providing ease of use in the lab. Because neurons can exist in the body over a lifetime, long-term culture systems are necessary so as to closely mimic the physiological conditions under laboratory culture conditions. Ideally, such a neuronal organoid culture would contain multiple cell types, be highly differentiated, and have a high density of interconnected cells. However, before these types of cultures can be created, certain problems associated with long-term neuronal culturing must be addressed. We sought to develop a new protocol which may further prolong the duration and integrity of E18 rat hippocampal cultures. We have developed a protocol that allows for culturing of E18 hippocampal neurons at high densities for more than 120 days. These cultured hippocampal neurons are (i) well differentiated with high numbers of synapses, (ii) anchored securely to their substrate, (iii) have high levels of functional connectivity, and (iv) form dense multi-layered cellular networks. We propose that our culture methodology is likely to be effective for multiple neuronal subtypes-particularly those that can be grown in Neurobasal/B27 media. This methodology presents new avenues for long-term functional studies in neurons.
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Affiliation(s)
- George K. Todd
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
- Molecular, Cellular and Integrative Physiology Graduate Group, University of California Davis, Davis, California, United States of America
| | - Casey A. Boosalis
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
- Molecular, Cellular and Integrative Physiology Graduate Group, University of California Davis, Davis, California, United States of America
| | - Aaron A. Burzycki
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
| | - Michael Q. Steinman
- Molecular, Cellular and Integrative Physiology Graduate Group, University of California Davis, Davis, California, United States of America
- Department of Psychology, University of California Davis, Davis, California, United States of America
| | - Lynda D. Hester
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland, United States of America
| | | | - Randen L. Patterson
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Biochemistry, School of Medicine, University of California Davis, Davis, California, United States of America
- The Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
- * E-mail:
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279
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Cao Z, Hulsizer S, Cui Y, Pretto DL, Kim KH, Hagerman PJ, Tassone F, Pessah IN. Enhanced asynchronous Ca(2+) oscillations associated with impaired glutamate transport in cortical astrocytes expressing Fmr1 gene premutation expansion. J Biol Chem 2013; 288:13831-41. [PMID: 23553633 DOI: 10.1074/jbc.m112.441055] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND FMR1 CGG expansion repeats in the premutation range have not been linked to astrocyte pathophysiology. RESULTS Premutation cortical astrocytes display decreased Glu transporter expression/activity and enhanced asynchronous Ca(2+) oscillations. CONCLUSION Glu transport and Ca(2+) signaling defects in premutation astrocytes could contribute to FXTAS neuropathology. SIGNIFICANCE Premutation astrocytes may have an etiological role in FXTAS neuropathology. Premutation CGG repeat expansions (55-200 CGG repeats; preCGG) within the fragile X mental retardation 1 (FMR1) gene can cause fragile X-associated tremor/ataxia syndrome. Defects in early neuronal migration and morphology, electrophysiological activity, and mitochondria trafficking have been described in a premutation mouse model, but whether preCGG mutations also affect astrocyte function remains unknown. PreCGG cortical astrocytes (∼170 CGG repeats) displayed 3-fold higher Fmr1 mRNA and 30% lower FMR1 protein (FMRP) when compared with WT. PreCGG astrocytes showed modest reductions in expression of glutamate (Glu) transporters GLT-1 and GLAST and attenuated Glu uptake (p < 0.01). Consistent with astrocyte cultures in vitro, aged preCGG mice cerebral cortex also displayed reduced GLAST and GLT-1 expression. Approximately 65% of the WT and preCGG cortical astrocytes displayed spontaneous asynchronous Ca(2+) oscillations. PreCGG astrocytes exhibited nearly 50% higher frequency of asynchronous Ca(2+) oscillations (p < 0.01) than WT, a difference mimicked by chronic exposure of WT astrocytes to l-trans-pyrrolidine-2,4-dicarboxylic acid (l-trans-PDC) or by partial suppression of GLAST using siRNA interference. Acute challenge with Glu augmented the frequency of Ca(2+) oscillations in both genotypes. Additionally, 10 μm Glu elicited a sustained intracellular Ca(2+) rise in a higher portion of preCGG astrocytes when compared with WT. Pharmacological studies showed that mGluR5, but not NMDA receptor, contributed to Glu hypersensitivity in preCGG astrocytes. These functional defects in preCGG astrocytes, especially in Glu signaling, may contribute to fragile X-associated tremor/ataxia syndrome neuropathology.
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Affiliation(s)
- Zhengyu Cao
- Department of Molecular Biosciences, School of Veterinary Medicine, University ofCalifornia, Davis, California 95616, USA.
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280
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Kozlov AY, Abramova AY, Nikenina EV. Nociceptive Thresholds in Rats in Response to Lipopolysaccharide Injection into the Specific Nuclei of the Thalamus of the Brain. Bull Exp Biol Med 2013; 154:711-3. [DOI: 10.1007/s10517-013-2036-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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281
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Complex Actions of Ionomycin in Cultured Cerebellar Astrocytes Affecting Both Calcium-Induced Calcium Release and Store-Operated Calcium Entry. Neurochem Res 2013; 38:1260-5. [DOI: 10.1007/s11064-013-1021-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 03/12/2013] [Indexed: 10/27/2022]
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282
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Astrocytes--multitaskers in chronic pain. Eur J Pharmacol 2013; 716:120-8. [PMID: 23528354 DOI: 10.1016/j.ejphar.2013.03.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 02/20/2013] [Accepted: 03/04/2013] [Indexed: 12/31/2022]
Abstract
Treatment of chronic pain remains a clinical challenge and sufficient pharmacological management is difficult to achieve without concurrent adverse drug effects. Recently the concept of chronic pain as a solely neuron-mediated phenomenon has evolved and it is now appreciated that also glial cells are of critical importance in pain generation and modulation. Astrocytes are macroglial cells that have close structural relationships with neurons; they contact neuronal somata and dendrites and enwrap synapses, where small astrocytic processes have been shown to be highly motile. This organization allows astrocytes to directly influence and coordinate neurons located within their structural domains. Moreover, astrocytes form astroglial networks and calcium wave propagations can spread through neighbouring astrocytes. ATP, which is released from astrocytes in response to elevated intracellular calcium concentrations, can contribute to the central mechanisms in chronic pain via purinergic receptors. In this review we highlight the structural organization and the functionalities of astrocytes that allow them to undertake critical roles in pain processing and we stress the possibility that astrocytes contribute to chronic pain not via a single pathway, but by undertaking various roles depending on the pain condition.
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283
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Roth TC, Chevalier DM, LaDage LD, Pravosudov VV. Variation in hippocampal glial cell numbers in food-caching birds from different climates. Dev Neurobiol 2013; 73:480-5. [DOI: 10.1002/dneu.22074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 12/17/2012] [Accepted: 01/25/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Timothy C. Roth
- Department of Psychology; Franklin and Marshall College; Lancaster; Pennsylvania; 17604
| | | | - Lara D. LaDage
- Department of Biology; University of Nevada; Reno; Nevada; 89509
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284
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Heinrich A, Andó RD, Túri G, Rózsa B, Sperlágh B. K+ depolarization evokes ATP, adenosine and glutamate release from glia in rat hippocampus: a microelectrode biosensor study. Br J Pharmacol 2013; 167:1003-20. [PMID: 22394324 DOI: 10.1111/j.1476-5381.2012.01932.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE This study was undertaken to characterize the ATP, adenosine and glutamate outflow evoked by depolarization with high K(+) concentrations, in slices of rat hippocampus. EXPERIMENTAL APPROACH We utilized the microelectrode biosensor technique and extracellular electrophysiological recording for the real-time monitoring of the efflux of ATP, adenosine and glutamate. KEY RESULTS ATP, adenosine and glutamate sensors exhibited transient and reversible current during depolarization with 25 mM K(+) , with distinct kinetics. The ecto-ATPase inhibitor ARL67156 enhanced the extracellular level of ATP and inhibited the prolonged adenosine efflux, suggesting that generation of adenosine may derive from the extracellular breakdown of ATP. Stimulation-evoked ATP, adenosine and glutamate efflux was inhibited by tetrodotoxin, while exposure to Ca(2+) -free medium abolished ATP and adenosine efflux from hippocampal slices. Extracellular elevation of ATP and adenosine were decreased in the presence of NMDA receptor antagonists, D-AP-5 and ifenprodil, whereas non-NMDA receptor blockade by CNQX inhibited glutamate but not ATP and adenosine efflux. The gliotoxin fluoroacetate and P2X7 receptor antagonists inhibited the K(+) -evoked ATP, adenosine and glutamate efflux, while carbenoxolone in low concentration and probenecid decreased only the adenosine efflux. CONCLUSIONS AND IMPLICATIONS Our results demonstrated activity-dependent gliotransmitter release in the hippocampus in response to ongoing neuronal activity. ATP and glutamate were released by P2X7 receptor activation into extracellular space. Although the increased extracellular levels of adenosine did derive from released ATP, adenosine might also be released directly via pannexin hemichannels.
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Affiliation(s)
- A Heinrich
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary Femtonics Ltd, Budapest, Hungary
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285
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Potokar M, Stenovec M, Jorgačevski J, Holen T, Kreft M, Ottersen OP, Zorec R. Regulation of AQP4 surface expression via vesicle mobility in astrocytes. Glia 2013; 61:917-28. [DOI: 10.1002/glia.22485] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 01/28/2013] [Indexed: 11/05/2022]
Affiliation(s)
| | | | | | - Torgeir Holen
- Center for Molecular Biology and Neuroscience; University of Oslo; Oslo; Norway
| | | | - Ole Petter Ottersen
- Center for Molecular Biology and Neuroscience; University of Oslo; Oslo; Norway
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286
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Dual phases of respiration chain defect-augmented mROS-mediated mCa 2+ stress during oxidative insult in normal and ρ 0 RBA1 astrocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:159567. [PMID: 23533684 PMCID: PMC3603293 DOI: 10.1155/2013/159567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 01/08/2013] [Indexed: 01/18/2023]
Abstract
Mitochondrial respiratory chain (RC) deficits, resulting in augmented mitochondrial ROS (mROS) generation, underlie pathogenesis of astrocytes. However, mtDNA-depleted cells (ρ0) lacking RC have been reported to be either sensitive or resistant to apoptosis. In this study, we sought to determine the effects of RC-enhanced mitochondrial stress following oxidative insult. Using noninvasive fluorescence probe-coupled laser scanning imaging microscopy, the ability to resist oxidative stress and levels of mROS formation and mitochondrial calcium (mCa2+) were compared between two different astrocyte cell lines, control and ρ0 astrocytes, over time upon oxidative stress. Our results showed that the cytoplasmic membrane becomes permeated with YO-PRO-1 dye at 150 and 130 minutes in RBA-1 and ρ0 astrocytes, respectively. In contrast to RBA-1, 30 minutes after 20 mM H2O2 exposure, ρ0 astrocytes formed marked plasma membrane blebs, lost the ability to retain Mito-R, and showed condensation of nuclei. Importantly, H2O2-induced ROS and accompanied mCa2+ elevation in control showed higher levels than ρ0 at early time point but vice versa at late time point. Our findings underscore dual phase of RC-defective cells harboring less mitochondrial stress due to low RC activity during short-term oxidative stress but augmented mROS-mediated mCa2+ stress during severe oxidative insult.
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287
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Zeidán-Chuliá F, Rybarczyk-Filho JL, Salmina AB, de Oliveira BHN, Noda M, Moreira JCF. Exploring the Multifactorial Nature of Autism Through Computational Systems Biology: Calcium and the Rho GTPase RAC1 Under the Spotlight. Neuromolecular Med 2013; 15:364-83. [DOI: 10.1007/s12017-013-8224-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 02/16/2013] [Indexed: 01/08/2023]
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288
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Czéh B, Di Benedetto B. Antidepressants act directly on astrocytes: evidences and functional consequences. Eur Neuropsychopharmacol 2013; 23:171-85. [PMID: 22609317 DOI: 10.1016/j.euroneuro.2012.04.017] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 04/27/2012] [Indexed: 11/24/2022]
Abstract
Post-mortem histopathological studies report on reduced glial cell numbers in various frontolimbic areas of depressed patients implying that glial loss together with abnormal functioning could contribute to the pathophysiology of mood disorders. Astrocytes are regarded as the most abundant cell type in the brain and known for their housekeeping functions, but as recent developments suggest, they are also dynamic regulators of synaptogenesis, synaptic strength and stability and they control adult hippocampal neurogenesis. The primary aim of this review was to summarize the abundant experimental evidences demonstrating that antidepressant therapies have profound effect on astrocytes. Antidepressants modify astroglial physiology, morphology and by affecting gliogenesis they probably even regulate glial cell numbers. Antidepressants affect intracellular signaling pathways and gene expression of astrocytes, as well as the expression of receptors and the release of various trophic factors. We also assess the potential functional consequences of these changes on glutamate and glucose homeostasis and on synaptic communication between the neurons. We propose here a hypothesis that antidepressant treatment not only affects neurons, but also activates astrocytes, triggering them to carry out specific functions that result in the reactivation of cortical plasticity and can lead to the readjustment of abnormal neuronal networks. We argue here that these astrocyte specific changes are likely to contribute to the therapeutic effectiveness of the currently available antidepressant treatments and the better understanding of these cellular and molecular processes could help us to identify novel targets for the development of antidepressant drugs.
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Affiliation(s)
- Boldizsár Czéh
- Max-Planck-Institute of Psychiatry, 80804 Munich, Germany.
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289
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Astrocytes protect neurons against methylmercury via ATP/P2Y(1) receptor-mediated pathways in astrocytes. PLoS One 2013; 8:e57898. [PMID: 23469098 PMCID: PMC3585279 DOI: 10.1371/journal.pone.0057898] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/27/2013] [Indexed: 11/19/2022] Open
Abstract
Methylmercury (MeHg) is a well known environmental pollutant that induces serious neuronal damage. Although MeHg readily crosses the blood-brain barrier, and should affect both neurons and glial cells, how it affects glia or neuron-to-glia interactions has received only limited attention. Here, we report that MeHg triggers ATP/P2Y1 receptor signals in astrocytes, thereby protecting neurons against MeHg via interleukin-6 (IL-6)-mediated pathways. MeHg increased several mRNAs in astrocytes, among which IL-6 was the highest. For this, ATP/P2Y1 receptor-mediated mechanisms were required because the IL-6 production was (i) inhibited by a P2Y1 receptor antagonist, MRS2179, (ii) abolished in astrocytes obtained from P2Y1 receptor-knockout mice, and (iii) mimicked by exogenously applied ATP. In addition, (iv) MeHg released ATP by exocytosis from astrocytes. As for the intracellular mechanisms responsible for IL-6 production, p38 MAP kinase was involved. MeHg-treated astrocyte-conditioned medium (ACM) showed neuro-protective effects against MeHg, which was blocked by anti-IL-6 antibody and was mimicked by the application of recombinant IL-6. As for the mechanism of neuro-protection by IL-6, an adenosine A1 receptor-mediated pathway in neurons seems to be involved. Taken together, when astrocytes sense MeHg, they release ATP that autostimulates P2Y1 receptors to upregulate IL-6, thereby leading to A1 receptor-mediated neuro-protection against MeHg.
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290
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Panossian A, Hamm R, Kadioglu O, Wikman G, Efferth T. Synergy and Antagonism of Active Constituents of ADAPT-232 on Transcriptional Level of Metabolic Regulation of Isolated Neuroglial Cells. Front Neurosci 2013; 7:16. [PMID: 23430930 PMCID: PMC3576868 DOI: 10.3389/fnins.2013.00016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 02/01/2013] [Indexed: 12/16/2022] Open
Abstract
Gene expression profiling was performed on the human neuroglial cell line T98G after treatment with adaptogen ADAPT-232 and its constituents – extracts of Eleutherococcus senticosus root, Schisandra chinensis berry, and Rhodiola rosea root as well as several constituents individually, namely, eleutheroside E, schizandrin B, salidroside, triandrin, and tyrosol. A common feature for all tested adaptogens was their effect on G-protein-coupled receptor signaling pathways, i.e., cAMP, phospholipase C (PLC), and phosphatidylinositol signal transduction pathways. Adaptogens may reduce the cAMP level in brain cells by down-regulation of adenylate cyclase gene ADC2Y and up-regulation of phosphodiesterase gene PDE4D that is essential for energy homeostasis as well as for switching from catabolic to anabolic states and vice versa. Down-regulation of cAMP by adaptogens may decrease cAMP-dependent protein kinase A activity in various cells resulting in inhibition stress-induced catabolic transformations and saving of ATP for many ATP-dependant metabolic transformations. All tested adaptogens up-regulated the PLCB1 gene, which encodes phosphoinositide-specific PLC and phosphatidylinositol 3-kinases (PI3Ks), key players for the regulation of NF-κB-mediated defense responses. Other common targets of adaptogens included genes encoding ERα estrogen receptor (2.9–22.6 fold down-regulation), cholesterol ester transfer protein (5.1–10.6 fold down-regulation), heat shock protein Hsp70 (3.0–45.0 fold up-regulation), serpin peptidase inhibitor (neuroserpin), and 5-HT3 receptor of serotonin (2.2–6.6 fold down-regulation). These findings can be reconciled with the observed beneficial effects of adaptogens in behavioral, mental, and aging-associated disorders. Combining two or more active substances in one mixture significantly changes deregulated genes profiles: synergetic interactions result in activation of genes that none of the individual substances affected, while antagonistic interactions result in suppression some genes activated by individual substances. These interactions can have an influence on transcriptional control of metabolic regulation both on the cellular level and the level of the whole organism. Merging of deregulated genes array profiles and intracellular networks is specific to the new substance with unique pharmacological characteristics. Presumably, this phenomenon could be used to eliminate undesirable effects (e.g., toxic effects) and increase the selectivity of pharmacological intervention.
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291
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An optimized fluorescent probe for visualizing glutamate neurotransmission. Nat Methods 2013; 10:162-70. [PMID: 23314171 PMCID: PMC4469972 DOI: 10.1038/nmeth.2333] [Citation(s) in RCA: 644] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 12/11/2012] [Indexed: 11/08/2022]
Abstract
We describe an intensity-based glutamate-sensing fluorescent reporter (iGluSnFR) with signal-to-noise ratio and kinetics appropriate for in vivo imaging. We engineered iGluSnFR in vitro to maximize its fluorescence change, and we validated its utility for visualizing glutamate release by neurons and astrocytes in increasingly intact neurological systems. In hippocampal culture, iGluSnFR detected single field stimulus-evoked glutamate release events. In pyramidal neurons in acute brain slices, glutamate uncaging at single spines showed that iGluSnFR responds robustly and specifically to glutamate in situ, and responses correlate with voltage changes. In mouse retina, iGluSnFR-expressing neurons showed intact light-evoked excitatory currents, and the sensor revealed tonic glutamate signaling in response to light stimuli. In worms, glutamate signals preceded and predicted postsynaptic calcium transients. In zebrafish, iGluSnFR revealed spatial organization of direction-selective synaptic activity in the optic tectum. Finally, in mouse forelimb motor cortex, iGluSnFR expression in layer V pyramidal neurons revealed task-dependent single-spine activity during running.
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292
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Smythies J, Edelstein L. Transsynaptic modality codes in the brain: possible involvement of synchronized spike timing, microRNAs, exosomes and epigenetic processes. Front Integr Neurosci 2013; 6:126. [PMID: 23316146 PMCID: PMC3539687 DOI: 10.3389/fnint.2012.00126] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 12/13/2012] [Indexed: 11/13/2022] Open
Abstract
This paper surveys two different mechanisms by which a presynaptic cell can modulate the structure and function of the postsynaptic cell. We first present the evidence that this occurs, and then discuss two mechanisms that could bring this about. The first hypothesis relates to the long lasting effects that the spike patterns of presynaptic axons may exert by modulating activity-inducible programs in postsynaptic cells. The second hypothesis is based on recently obtained evidence that, the afferent neuron at the neuromuscular junction buds off exosomes at its synapse and carries a cargo of Wg and Evi, which are large molecular transsynaptic signaling agents (LMTSAs). Further evidence indicates that many types of neurons bud off exosomes containing payloads of various lipids, proteins, and types of RNA. The evidence suggests that they are transmitted across the synapse and are taken up by the postsynaptic structure either by perisynaptic or exosynaptic mechanisms, thus mediating the transfer of information between neurons. To date, the molecular hypothesis has been limited to local interactions within the synapse of concern. In this paper, we explore the possibility that this represents a mechanism for information transfer involving the postsynaptic neuron as a whole. This entails a review of the known functions of these molecules in neuronal physiology, together with an estimate of the possible types of information they could carry and how they might affect neurocomputations.
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Affiliation(s)
- John Smythies
- Center for Brain and Cognition, University of California San Diego La Jolla, CA, SA
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293
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Abstract
The master coordinator of daily schedules in mammals, located in the ventral hypothalamus, is the suprachiasmatic nucleus (SCN). This relatively small population of neurons and glia generates circadian rhythms in physiology and behavior and synchronizes them to local time. Recent advances have begun to define the roles of specific cells and signals (e.g., peptides, amino acids, and purine derivatives) within this network that generate and synchronize daily rhythms. Here we focus on the best-studied signals between neurons and between glia in the mammalian circadian system with an emphasis on time-of-day pharmacology. Where possible, we highlight how commonly used drugs affect the circadian system.
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294
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Streifel K, Miller J, Mouneimne R, Tjalkens RB. Manganese inhibits ATP-induced calcium entry through the transient receptor potential channel TRPC3 in astrocytes. Neurotoxicology 2013; 34:160-6. [PMID: 23131343 PMCID: PMC3557543 DOI: 10.1016/j.neuro.2012.10.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/05/2012] [Accepted: 10/25/2012] [Indexed: 11/26/2022]
Abstract
Chronic exposure to elevated levels of manganese (Mn(2+)) causes neuronal injury and inflammatory activation of glia. Astrocytes selectively accumulate Mn(2+), which inhibits mitochondrial respiration and increases production of reactive oxygen species. We previously reported that sub-acute exposure to low micromolar levels of Mn(2+) in primary astrocytes inhibited ATP-induced calcium (Ca(2+)) signaling, associated with decreased levels of endoplasmic reticulum Ca(2+) and increased mitochondrial Ca(2+) loads. In the present studies, we postulated that the mechanism underlying the capacity of Mn(2+) to inhibit these purinergic signals in astrocytes could be due to competition with Ca(2+) for entry through a plasma membrane channel. These data demonstrate that acutely applied Mn(2+) rapidly inhibited ATP-induced Ca(2+) waves and transients in primary striatal astrocytes. Mn(2+) also decreased influx of extracellular Ca(2+) induced by 1-oleoyl-2-acetyl-sn-glycerol (OAG), a direct activator of the transient receptor potential channel, TRPC3. The TRPC3 inhibitor, pyrazole-3, prevented ATP- and OAG-dependent transport of Mn(2+) from extracellular stores, demonstrated by a dramatic reduction in the rate of fluorescence quenching of Fura-2. These data indicate that Mn(2+) can acutely inhibit ATP-dependent Ca(2+) signaling in astrocytes by blocking Ca(2+) entry through the receptor-operated cation channel, TRPC3. Loss of normal astrocytic responses to purinergic signals due to accumulation of Mn(2+) could therefore comprise critical homeostatic functions necessary for metabolic and trophic support of neurons.
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Affiliation(s)
- Karin Streifel
- Center for Environmental Medicine, Department of Environmental and Radiological Health Sciences, Colorado State University
| | - James Miller
- Center for Environmental Medicine, Department of Environmental and Radiological Health Sciences, Colorado State University
| | - Rola Mouneimne
- Department of Veterinary Integrative Biosciences, Texas A&M University
| | - Ronald B. Tjalkens
- Center for Environmental Medicine, Department of Environmental and Radiological Health Sciences, Colorado State University
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295
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Abstract
Major depressive disorder is a debilitating condition with a lifetime risk of ten percent. Most treatments take several weeks to achieve clinical efficacy, limiting the ability to bring instant relief needed in psychiatric emergencies. One intervention that rapidly alleviates depressive symptoms is sleep deprivation; however, its mechanism of action is unknown. Astrocytes regulate responses to sleep deprivation, raising the possibility that glial signaling mediates antidepressive-like actions of sleep deprivation. Here, we found that astrocytic signaling to adenosine (A1) receptors was required for the robust reduction of depressive-like behaviors following 12 hours of sleep deprivation. As sleep deprivation activates synaptic A1 receptors, we mimicked the effect of sleep deprivation on depression phenotypes by administration of the A1 agonist CCPA. These results provide the first mechanistic insight into how sleep deprivation impacts mood, and provide a novel pathway for rapid antidepressant development by modulation of glial signaling in the brain.
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296
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Electrophysiological Study of the Antinociception Produced by the Coapplication of (±)-CPP and Propentofylline in Monoarthritic Rats. ISRN PAIN 2013; 2013:315626. [PMID: 27335873 PMCID: PMC4893406 DOI: 10.1155/2013/315626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/15/2013] [Indexed: 11/29/2022]
Abstract
The NMDA receptor is central in the generation and maintenance of chronic pain. This receptor has several sites of modulation. One is the glutamate recognition site that can be blocked by (±)-3-(2-carboxypiperazin-yl)propyl-1-phosphoric acid or (±)-CPP. We investigated whether the effect of glial inhibition produced by propentophylline (PPF) can be enhanced when combined with (±)-CPP. We used Sprague-Dawley rats with experimental monoarthritis, administering intrathecally the ED30 for both drugs (3.97 μg of (±)-CPP and 1.42 μg of PPF), since this combination produces an antinociceptive supra-additive effect when used in mechanical nociception (Randall-Selitto test). The combination of (±)-PPF and CPP produced an antinociceptive effect which was greater than that each drug alone as tested by both the C reflex and windup. We conclude that the antinociceptive effect of the combination of (±)-PPF and CPP possibly generates a supra additive interaction type in monoarthritic rats.
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297
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McCullough SD, Xu X, Dent SYR, Bekiranov S, Roeder RG, Grant PA. Reelin is a target of polyglutamine expanded ataxin-7 in human spinocerebellar ataxia type 7 (SCA7) astrocytes. Proc Natl Acad Sci U S A 2012; 109:21319-24. [PMID: 23236151 PMCID: PMC3535616 DOI: 10.1073/pnas.1218331110] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Spinocerebellar ataxia type 7 (SCA7) is an autosomal-dominant neurodegenerative disorder that results from polyglutamine expansion of the ataxin-7 (ATXN7) protein. Remarkably, although mutant ATXN7 is expressed throughout the body, pathology is restricted primarily to the cerebellum and retina. One major goal has been to identify factors that contribute to the tissue specificity of SCA7. Here we describe the development and use of a human astrocyte cell culture model to identify reelin, a factor intimately involved in the development and maintenance of Purkinje cells and the cerebellum as a whole, as an ATXN7 target gene. We found that polyglutamine expansion decreased ATXN7 occupancy, which correlated with increased levels of histone H2B monoubiquitination, at the reelin promoter. Treatment with trichostatin A, but not other histone deacetylase inhibitors, partially restored reelin transcription and promoted the accumulation of mutant ATXN7 into nuclear inclusions. Our findings suggest that reelin could be a previously unknown factor involved in the tissue specificity of SCA7 and that trichostatin A may ameliorate deleterious effects of the mutant ATXN7 protein by promoting its sequestration away from promoters into nuclear inclusions.
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Affiliation(s)
- Shaun D. McCullough
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Xiaojiang Xu
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Sharon Y. R. Dent
- Department of Molecular Carcinogenesis at the Virginia Harris Cockrell Cancer Research Center, University of Texas M. D. Anderson Cancer Center, Smithville, TX 78957; and
| | - Stefan Bekiranov
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Robert G. Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065
| | - Patrick A. Grant
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908
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298
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De Pittà M, Volman V, Berry H, Parpura V, Volterra A, Ben-Jacob E. Computational quest for understanding the role of astrocyte signaling in synaptic transmission and plasticity. Front Comput Neurosci 2012; 6:98. [PMID: 23267326 PMCID: PMC3528083 DOI: 10.3389/fncom.2012.00098] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 12/06/2012] [Indexed: 01/08/2023] Open
Abstract
The complexity of the signaling network that underlies astrocyte-synapse interactions may seem discouraging when tackled from a theoretical perspective. Computational modeling is challenged by the fact that many details remain hitherto unknown and conventional approaches to describe synaptic function are unsuitable to explain experimental observations when astrocytic signaling is taken into account. Supported by experimental evidence is the possibility that astrocytes perform genuine information processing by means of their calcium signaling and are players in the physiological setting of the basal tone of synaptic transmission. Here we consider the plausibility of this scenario from a theoretical perspective, focusing on the modulation of synaptic release probability by the astrocyte and its implications on synaptic plasticity. The analysis of the signaling pathways underlying such modulation refines our notion of tripartite synapse and has profound implications on our understanding of brain function.
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Affiliation(s)
- Maurizio De Pittà
- School of Physics and Astronomy, Tel Aviv University Ramat Aviv, Israel
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299
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Tong X, Shigetomi E, Looger LL, Khakh BS. Genetically Encoded Calcium Indicators and Astrocyte Calcium Microdomains. Neuroscientist 2012; 19:274-91. [DOI: 10.1177/1073858412468794] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The discovery of intracellular Ca2+ signals within astrocytes has changed our view of how these ubiquitous cells contribute to brain function. Classically thought merely to serve supportive functions, astrocytes are increasingly thought to respond to, and regulate, neurons. The use of organic Ca2+ indicator dyes such as Fluo-4 and Fura-2 has proved instrumental in the study of astrocyte physiology. However, progress has recently been accelerated by the use of cytosolic and membrane targeted genetically encoded calcium indicators (GECIs). Herein, we review these recent findings, discuss why studying astrocyte Ca2+ signals is important to understand brain function, and summarize work that led to the discovery of TRPA1 channel-mediated near-membrane Ca2+ signals in astrocytes and their indirect neuromodulatory roles at inhibitory synapses in the CA1 stratum radiatum region of the hippocampus. We suggest that the use of membrane-targeted and cytosolic GECIs holds great promise to explore the diversity of Ca2+ signals within single astrocytes and also to study diversity of function for astrocytes in different parts of the brain.
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Affiliation(s)
- Xiaoping Tong
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Eiji Shigetomi
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Department of Pharmacology, Faculty of Medicine, University of Yamanashi Chuo, Yamanashi, Japan
| | - Loren L. Looger
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Baljit S. Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
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300
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Yang CY, Matsuzaki T, Iijima N, Kajimura N, Ozawa H. Morphofunctional changes of the astrocyte in rat hippocampus under different corticosteroid conditions. Med Mol Morphol 2012; 45:206-13. [DOI: 10.1007/s00795-011-0561-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 08/12/2011] [Indexed: 10/27/2022]
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