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Mitroshina E, Kalinina E, Vedunova M. Optogenetics in Alzheimer's Disease: Focus on Astrocytes. Antioxidants (Basel) 2023; 12:1856. [PMID: 37891935 PMCID: PMC10604138 DOI: 10.3390/antiox12101856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/27/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia, resulting in disability and mortality. The global incidence of AD is consistently surging. Although numerous therapeutic agents with promising potential have been developed, none have successfully treated AD to date. Consequently, the pursuit of novel methodologies to address neurodegenerative processes in AD remains a paramount endeavor. A particularly promising avenue in this search is optogenetics, enabling the manipulation of neuronal activity. In recent years, research attention has pivoted from neurons to glial cells. This review aims to consider the potential of the optogenetic correction of astrocyte metabolism as a promising strategy for correcting AD-related disorders. The initial segment of the review centers on the role of astrocytes in the genesis of neurodegeneration. Astrocytes have been implicated in several pathological processes associated with AD, encompassing the clearance of β-amyloid, neuroinflammation, excitotoxicity, oxidative stress, and lipid metabolism (along with a critical role in apolipoprotein E function). The effect of astrocyte-neuronal interactions will also be scrutinized. Furthermore, the review delves into a number of studies indicating that changes in cellular calcium (Ca2+) signaling are one of the causes of neurodegeneration. The review's latter section presents insights into the application of various optogenetic tools to manipulate astrocytic function as a means to counteract neurodegenerative changes.
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Affiliation(s)
- Elena Mitroshina
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia (M.V.)
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Eitelmann S, Everaerts K, Petersilie L, Rose CR, Stephan J. Ca 2+-dependent rapid uncoupling of astrocytes upon brief metabolic stress. Front Cell Neurosci 2023; 17:1151608. [PMID: 37886111 PMCID: PMC10598858 DOI: 10.3389/fncel.2023.1151608] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 08/23/2023] [Indexed: 10/28/2023] Open
Abstract
Astrocytic gap junctional coupling is a major element in neuron-glia interaction. There is strong evidence that impaired coupling is involved in neurological disorders. Reduced coupling was, e.g., demonstrated for core regions of ischemic stroke that suffer from massive cell death. In the surrounding penumbra, cells may recover, but recovery is hampered by spreading depolarizations, which impose additional metabolic stress onto the tissue. Spreading depolarizations are characterized by transient breakdown of cellular ion homeostasis, including pH and Ca2+, which might directly affect gap junctional coupling. Here, we exposed acute mouse neocortical tissue slices to brief metabolic stress and examined its effects on the coupling strength between astrocytes. Changes in gap junctional coupling were assessed by recordings of the syncytial isopotentiality. Moreover, quantitative ion imaging was performed in astrocytes to analyze the mechanisms triggering the observed changes. Our experiments show that a 2-minute perfusion of tissue slices with blockers of glycolysis and oxidative phosphorylation causes a rapid uncoupling in half of the recorded cells. They further indicate that uncoupling is not mediated by the accompanying (moderate) intracellular acidification. Dampening large astrocytic Ca2+ loads by removal of extracellular Ca2+ or blocking Ca2+ influx pathways as well as a pharmacological inhibition of calmodulin, however, prevent the uncoupling. Taken together, we conclude that astrocytes exposed to brief episodes of metabolic stress can undergo a rapid, Ca2+/calmodulin-dependent uncoupling. Such uncoupling may help to confine and reduce cellular damage in the ischemic penumbra in vivo.
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Affiliation(s)
| | | | | | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jonathan Stephan
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Lim D, Tapella L, Dematteis G, Talmon M, Genazzani AA. Calcineurin Signalling in Astrocytes: From Pathology to Physiology and Control of Neuronal Functions. Neurochem Res 2023; 48:1077-1090. [PMID: 36083398 PMCID: PMC10030417 DOI: 10.1007/s11064-022-03744-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 07/31/2022] [Accepted: 08/29/2022] [Indexed: 10/14/2022]
Abstract
Calcineurin (CaN), a Ca2+/calmodulin-activated serine/threonine phosphatase, acts as a Ca2+-sensitive switch regulating cellular functions through protein dephosphorylation and activation of gene transcription. In astrocytes, the principal homeostatic cells in the CNS, over-activation of CaN is known to drive pathological transcriptional remodelling, associated with neuroinflammation in diseases such as Alzheimer's disease, epilepsy and brain trauma. Recent reports suggest that, in physiological conditions, the activity of CaN in astrocytes is transcription-independent and is required for maintenance of basal protein synthesis rate and activation of astrocytic Na+/K+ pump thereby contributing to neuronal functions such as neuronal excitability and memory formation. In this contribution we overview the role of Ca2+ and CaN signalling in astroglial pathophysiology focusing on the emerging physiological role of CaN in astrocytes. We propose a model for the context-dependent switch of CaN activity from the post-transcriptional regulation of cell proteostasis in healthy astrocytes to the CaN-dependent transcriptional activation in neuroinflammation-associated diseases.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy.
| | - Laura Tapella
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy
| | - Giulia Dematteis
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy
| | - Maria Talmon
- Department of Health Sciences, School of Medicine, Università del Piemonte Orientale "Amedeo Avogadro", Via Solaroli 17, 28100, Novara, Italy
| | - Armando A Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy.
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Jiang H, Zhang Y, Wang ZZ, Chen NH. Connexin 43: An Interface Connecting Neuroinflammation to Depression. Molecules 2023; 28:molecules28041820. [PMID: 36838809 PMCID: PMC9961786 DOI: 10.3390/molecules28041820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Major depressive disorder (MDD) is a leading chronic mental illness worldwide, characterized by anhedonia, pessimism and even suicidal thoughts. Connexin 43 (Cx43), mainly distributed in astrocytes of the brain, is by far the most widely and ubiquitously expressed connexin in almost all vital organs. Cx43 forms gap junction channels in the brain, which mediate energy exchange and effectively maintain physiological homeostasis. Increasing evidence suggests the crucial role of Cx43 in the pathogenesis of MDD. Neuroinflammation is one of the most common pathological features of the central nervous system dysfunctions. Inflammatory factors are abnormally elevated in patients with depression and are closely related to nearly all links of depression. After activating the inflammatory pathway in the brain, the release and uptake of glutamate and adenosine triphosphate, through Cx43 in the synaptic cleft, would be affected. In this review, we have summarized the association between Cx43 and neuroinflammation, the cornerstones linking inflammation and depression, and Cx43 abnormalities in depression. We also discuss the significant association of Cx43 in inflammation and depression, which will help to explore new antidepressant drug targets.
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Affiliation(s)
- Hong Jiang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical, Science and Peking Union Medical College, Beijing 100050, China
| | - Yi Zhang
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical, Science and Peking Union Medical College, Beijing 100050, China
- Correspondence: (Z.-Z.W.); (N.-H.C.); Tel.: +86-10-6316-5182 (Z.-Z.W.); +86-10-63165177 (N.-H.C.)
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical, Science and Peking Union Medical College, Beijing 100050, China
- Correspondence: (Z.-Z.W.); (N.-H.C.); Tel.: +86-10-6316-5182 (Z.-Z.W.); +86-10-63165177 (N.-H.C.)
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Benedikt J, Malpica-Nieves CJ, Rivera Y, Méndez-González M, Nichols CG, Veh RW, Eaton MJ, Skatchkov SN. The Polyamine Spermine Potentiates the Propagation of Negatively Charged Molecules through the Astrocytic Syncytium. Biomolecules 2022; 12:biom12121812. [PMID: 36551240 PMCID: PMC9775384 DOI: 10.3390/biom12121812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/16/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
The interest in astrocytes, the silent brain cells that accumulate polyamines (PAs), is growing. PAs exert anti-inflammatory, antioxidant, antidepressant, neuroprotective, and other beneficial effects, including increasing longevity in vivo. Unlike neurons, astrocytes are extensively coupled to others via connexin (Cx) gap junctions (GJs). Although there are striking modulatory effects of PAs on neuronal receptors and channels, PA regulation of the astrocytic GJs is not well understood. We studied GJ-propagation using molecules of different (i) electrical charge, (ii) structure, and (iii) molecular weight. Loading single astrocytes with patch pipettes containing membrane-impermeable dyes, we observed that (i) even small molecules do not easily permeate astrocytic GJs, (ii) the ratio of the charge to weight of these molecules is the key determinant of GJ permeation, (iii) the PA spermine (SPM) induced the propagation of negatively charged molecules via GJs, (iv) while no effects were observed on propagation of macromolecules with net-zero charge. The GJ uncoupler carbenoxolone (CBX) blocked such propagation. Taken together, these findings indicate that SPM is essential for astrocytic GJ communication and selectively facilitates intracellular propagation via GJs for negatively charged molecules through glial syncytium.
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Affiliation(s)
- Jan Benedikt
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | - Christian J. Malpica-Nieves
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Correspondence: (C.J.M.-N.); (S.N.S.); Tel.: +1-787-798-3001 (ext. 2057) (S.N.S.)
| | - Yomarie Rivera
- Department of Chiropractic, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | | | - Colin G. Nichols
- Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rüdiger W. Veh
- Institut für Zell- und Neurobiologie, Charité, 10115 Berlin, Germany
| | - Misty J. Eaton
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | - Serguei N. Skatchkov
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Correspondence: (C.J.M.-N.); (S.N.S.); Tel.: +1-787-798-3001 (ext. 2057) (S.N.S.)
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Burboa PC, Puebla M, Gaete PS, Durán WN, Lillo MA. Connexin and Pannexin Large-Pore Channels in Microcirculation and Neurovascular Coupling Function. Int J Mol Sci 2022; 23:ijms23137303. [PMID: 35806312 PMCID: PMC9266979 DOI: 10.3390/ijms23137303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 01/27/2023] Open
Abstract
Microcirculation homeostasis depends on several channels permeable to ions and/or small molecules that facilitate the regulation of the vasomotor tone, hyperpermeability, the blood–brain barrier, and the neurovascular coupling function. Connexin (Cxs) and Pannexin (Panxs) large-pore channel proteins are implicated in several aspects of vascular physiology. The permeation of ions (i.e., Ca2+) and key metabolites (ATP, prostaglandins, D-serine, etc.) through Cxs (i.e., gap junction channels or hemichannels) and Panxs proteins plays a vital role in intercellular communication and maintaining vascular homeostasis. Therefore, dysregulation or genetic pathologies associated with these channels promote deleterious tissue consequences. This review provides an overview of current knowledge concerning the physiological role of these large-pore molecule channels in microcirculation (arterioles, capillaries, venules) and in the neurovascular coupling function.
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Affiliation(s)
- Pía C. Burboa
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Departamento de Morfología y Función, Facultad de Salud y Ciencias Sociales, Sede Santiago Centro, Universidad de las Américas, Avenue República 71, Santiago 8370040, Chile;
| | - Mariela Puebla
- Departamento de Morfología y Función, Facultad de Salud y Ciencias Sociales, Sede Santiago Centro, Universidad de las Américas, Avenue República 71, Santiago 8370040, Chile;
| | - Pablo S. Gaete
- Department of Physiology and Membrane Biology, University of California at Davis, Davis, CA 95616, USA;
| | - Walter N. Durán
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Rutgers School of Graduate Studies, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Mauricio A. Lillo
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Correspondence:
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Lin Y, Huang T, Shen W, Pang Q, Xie Q, Chen X, Tu F. TRPV1 Suppressed NLRP3 Through Regulating Autophagy in Microglia After Ischemia-Reperfusion Injury. J Mol Neurosci 2022; 72:792-801. [PMID: 35041191 DOI: 10.1007/s12031-021-01935-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 10/21/2021] [Indexed: 11/24/2022]
Abstract
The microglia-mediated inflammatory response is one of the main causes of brain tissue damage after stroke. In recent years, it has been reported that autophagy in microglia played an important role in inflammatory response after stroke. Transient receptor potential vanilloid 1 (TRPV1) has been shown to regulate autophagy and inflammatory in microglia; however, the detailed mechanisms remain unclear. This study aimed to investigate whether autophagy regulates inflammatory is associated with TRPV1. Model of oxygen and glucose deprivation/reoxygenation (OGD/R) was established in vitro to induce cerebral ischemia-reperfusion injury (I/R). siRNA of Atg5, inhibitors, and agonists of both autophagy and TRPV1 were involved in our study. Autophagy was assayed by immunofluorescence staining LC-3 and autophagosome was observed using transmission electron microscopy (TEM). Autophagy/inflammation-related markers as Atg5, LC-3II/LC-3I, Beclin-1, NLRP3, IL-1β, and Caspase-1 were also measured in the present study. Results indicated that I/R injury-induced inflammatory injury may be impeded by inhibition of autophagy, and TRPV1 could suppress OGD/R-induced autophagy of microglia. However, the effect of TRPV1's inhibitor on inflammatory response was attenuated when the autophagy was blocked. These findings suggested that TRPV1 exhibits an anti-inflammatory effect on OGD/R-induced microglia, which was at least correlated with the anti-autophagy action of TRPV1 partially.
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Affiliation(s)
- Yao Lin
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, Xueyuan West Road, Wenzhou, Zhejiang, China
| | - Tingting Huang
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, Xueyuan West Road, Wenzhou, Zhejiang, China
| | - Weimin Shen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, Xueyuan West Road, Wenzhou, Zhejiang, China
| | - Qiongyi Pang
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, Xueyuan West Road, Wenzhou, Zhejiang, China
| | - Qingfeng Xie
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, Xueyuan West Road, Wenzhou, Zhejiang, China
| | - Xiang Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, Xueyuan West Road, Wenzhou, Zhejiang, China.
| | - Fengxia Tu
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, Xueyuan West Road, Wenzhou, Zhejiang, China.
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Fernández-Bertólez N, Costa C, Brandão F, Teixeira JP, Pásaro E, Valdiglesias V, Laffon B. Toxicological Aspects of Iron Oxide Nanoparticles. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1357:303-350. [DOI: 10.1007/978-3-030-88071-2_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Claeys W, Van Hoecke L, Lefere S, Geerts A, Verhelst X, Van Vlierberghe H, Degroote H, Devisscher L, Vandenbroucke RE, Van Steenkiste C. The neurogliovascular unit in hepatic encephalopathy. JHEP Rep 2021; 3:100352. [PMID: 34611619 PMCID: PMC8476774 DOI: 10.1016/j.jhepr.2021.100352] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/14/2021] [Accepted: 07/23/2021] [Indexed: 12/14/2022] Open
Abstract
Hepatic encephalopathy (HE) is a neurological complication of hepatic dysfunction and portosystemic shunting. It is highly prevalent in patients with cirrhosis and is associated with poor outcomes. New insights into the role of peripheral origins in HE have led to the development of innovative treatment strategies like faecal microbiota transplantation. However, this broadening of view has not been applied fully to perturbations in the central nervous system. The old paradigm that HE is the clinical manifestation of ammonia-induced astrocyte dysfunction and its secondary neuronal consequences requires updating. In this review, we will use the holistic concept of the neurogliovascular unit to describe central nervous system disturbances in HE, an approach that has proven instrumental in other neurological disorders. We will describe HE as a global dysfunction of the neurogliovascular unit, where blood flow and nutrient supply to the brain, as well as the function of the blood-brain barrier, are impaired. This leads to an accumulation of neurotoxic substances, chief among them ammonia and inflammatory mediators, causing dysfunction of astrocytes and microglia. Finally, glymphatic dysfunction impairs the clearance of these neurotoxins, further aggravating their effect on the brain. Taking a broader view of central nervous system alterations in liver disease could serve as the basis for further research into the specific brain pathophysiology of HE, as well as the development of therapeutic strategies specifically aimed at counteracting the often irreversible central nervous system damage seen in these patients.
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Key Words
- ABC, ATP-binding cassette
- ACLF, acute-on-chronic liver failure
- AD, acute decompensation
- ALF, acute liver failure
- AOM, azoxymethane
- AQP4, aquaporin 4
- Acute Liver Failure
- Ammonia
- BBB, blood-brain barrier
- BCRP, breast cancer resistance protein
- BDL, bile duct ligation
- Blood-brain barrier
- Brain edema
- CCL, chemokine ligand
- CCR, C-C chemokine receptor
- CE, cerebral oedema
- CLD, chronic liver disease
- CLDN, claudin
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Cirrhosis
- Energy metabolism
- GS, glutamine synthetase
- Glymphatic system
- HE, hepatic encephalopathy
- HO-1, heme oxygenase 1
- IL-, interleukin
- MMP-9, matrix metalloproteinase 9
- MRP, multidrug resistance associated protein
- NGVU
- NGVU, neurogliovascular unit
- NKCC1, Na-K-2Cl cotransporter 1
- Neuroinflammation
- OCLN, occludin
- ONS, oxidative and nitrosative stress
- Oxidative stress
- P-gp, P-glycoprotein
- PCA, portacaval anastomosis
- PSS, portosystemic shunt
- S1PR2, sphingosine-1-phosphate receptor 2
- SUR1, sulfonylurea receptor 1
- Systemic inflammation
- TAA, thioacetamide
- TGFβ, transforming growth factor beta
- TJ, tight junction
- TNF, tumour necrosis factor
- TNFR1, tumour necrosis factor receptor 1
- ZO, zonula occludens
- mPT, mitochondrial pore transition
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Affiliation(s)
- Wouter Claeys
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
- Barriers in Inflammation, VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Lien Van Hoecke
- Barriers in Inflammation, VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Sander Lefere
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
- Gut-Liver Immunopharmacology Unit, Department of Basic and Applied Medical Sciences; Liver Research Center Ghent; Ghent University, Ghent, Belgium
| | - Anja Geerts
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Xavier Verhelst
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Hans Van Vlierberghe
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Helena Degroote
- Hepatology Research Unit, Department of Internal Medicine and Paediatrics, Liver Research Center Ghent, Ghent University, Ghent, Belgium
| | - Lindsey Devisscher
- Gut-Liver Immunopharmacology Unit, Department of Basic and Applied Medical Sciences; Liver Research Center Ghent; Ghent University, Ghent, Belgium
| | - Roosmarijn E. Vandenbroucke
- Barriers in Inflammation, VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Christophe Van Steenkiste
- Antwerp University, Department of Gastroenterology and Hepatology, Antwerp, Belgium
- Department of Gastroenterology and Hepatology, Maria Middelares Hospital, Ghent, Belgium
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Novel Approaches Used to Examine and Control Neurogenesis in Parkinson's Disease. Int J Mol Sci 2021; 22:ijms22179608. [PMID: 34502516 PMCID: PMC8431772 DOI: 10.3390/ijms22179608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 12/16/2022] Open
Abstract
Neurogenesis is a key mechanism of brain development and plasticity, which is impaired in chronic neurodegeneration, including Parkinson’s disease. The accumulation of aberrant α-synuclein is one of the features of PD. Being secreted, this protein produces a prominent neurotoxic effect, alters synaptic plasticity, deregulates intercellular communication, and supports the development of neuroinflammation, thereby providing propagation of pathological events leading to the establishment of a PD-specific phenotype. Multidirectional and ambiguous effects of α-synuclein on adult neurogenesis suggest that impaired neurogenesis should be considered as a target for the prevention of cell loss and restoration of neurological functions. Thus, stimulation of endogenous neurogenesis or cell-replacement therapy with stem cell-derived differentiated neurons raises new hopes for the development of effective and safe technologies for treating PD neurodegeneration. Given the rapid development of optogenetics, it is not surprising that this method has already been repeatedly tested in manipulating neurogenesis in vivo and in vitro via targeting stem or progenitor cells. However, niche astrocytes could also serve as promising candidates for controlling neuronal differentiation and improving the functional integration of newly formed neurons within the brain tissue. In this review, we mainly focus on current approaches to assess neurogenesis and prospects in the application of optogenetic protocols to restore the neurogenesis in Parkinson’s disease.
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Dzyubenko E, Prazuch W, Pillath-Eilers M, Polanska J, Hermann DM. Analysing Intercellular Communication in Astrocytic Networks Using "Astral". Front Cell Neurosci 2021; 15:689268. [PMID: 34211372 PMCID: PMC8239356 DOI: 10.3389/fncel.2021.689268] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/19/2021] [Indexed: 12/15/2022] Open
Abstract
Astrocytic networks are critically involved in regulating the activity of neuronal networks. However, a comprehensive and ready-to-use data analysis tool for investigating functional interactions between the astrocytes is missing. We developed the novel software package named "Astral" to analyse intercellular communication in astrocytic networks based on live-cell calcium imaging. Our method for analysing calcium imaging data does not require the assignment of regions of interest. The package contains two applications: the core processing pipeline for detecting and quantifying Ca++ events, and the auxiliary visualization tool for controlling data quality. Our method allows for the network-wide quantification of Ca++ events and the analysis of their intercellular propagation. In a set of proof-of-concept experiments, we examined Ca++ events in flat monolayers of primary astrocytes and confirmed that inter-astrocytic interactions depend on the permeability of gap junctions and connexin hemichannels. The Astral tool is particularly useful for studying astrocyte-neuronal interactions on the network level. We demonstrate that compared with purely astrocytic cultures, spontaneous generation of Ca++ events in astrocytes that were co-cultivated with neurons was significantly increased. Interestingly, the increased astrocytic Ca++ activity after long-term co-cultivation with neurons was driven by the enhanced formation of gap junctions and connexin hemichannels but was not affected by silencing neuronal activity. Our data indicate the necessity for systematic investigation of astrocyte-neuronal interactions at the network level. For this purpose, the Astral software offers a powerful tool for processing and quantifying calcium imaging data.
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Affiliation(s)
- Egor Dzyubenko
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Wojciech Prazuch
- Department of Data Science and Engineering, Silesian University of Technology Faculty of Automatic Control, Electronics and Computer Science, Gliwice, Poland
| | - Matthias Pillath-Eilers
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
| | - Joanna Polanska
- Department of Data Science and Engineering, Silesian University of Technology Faculty of Automatic Control, Electronics and Computer Science, Gliwice, Poland
| | - Dirk M Hermann
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Essen, Germany
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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Zhang S, Gong Y, Wang H, Li Z, Huang Y, Fu X, Xiang P, Fan T. AS602801 sensitizes glioma cells to temozolomide and vincristine by blocking gap junction communication between glioma cells and astrocytes. J Cell Mol Med 2021; 25:4062-4072. [PMID: 33609076 PMCID: PMC8051707 DOI: 10.1111/jcmm.16375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 01/27/2021] [Accepted: 02/02/2021] [Indexed: 12/28/2022] Open
Abstract
Previous studies showed that the chemotherapeutic effect of temozolomide (TMZ) and vincristine (VCR) against glioma might be blunted by the co‐culture with astrocytes, and connexin‐43 (CX43) was thought to play a vital role in the communication between glioma cells and astrocytes. In this study, we aimed to investigate the combined chemotherapeutic effect of AS602801 and TMZ/ VCR in glioma cells both. Dye transfer assay was used to evaluate the gap junction activity between U251 cells and astrocytes. Western blot and immunohistochemistry were carried out to analyse the expression of p‐JNK, CX43 and CASP‐3 proteins treated under different conditions. AS602801 significantly suppressed the gap junction activity between U251 cells and astrocytes. The expression of p‐JNK and CX43 was remarkably inhibited by AS602801. TMZ/VCR‐induced apoptosis of glioma cells was effectively enhanced by AS602801 treatment. Accordingly, the inhibitory role of TMZ/VCR in the expression of p‐JNK, CX43 and CASP‐3 in glioma cells was notably restored by AS602801. Furthermore, in a glioma cell xenograft, AS602801 showed an apparent capability to enhance TMZ/VCR‐induced tumour cell apoptosis through altering the expression of p‐JNK, CX43 and CASP‐3. The findings of this study demonstrated that the co‐culture of glioma cells with astrocytes blunted the tumour killing effect of TMZ and VCR. AS602801 down‐regulated CX43 expression by inhibiting JNK. And AS602801 also sensitized glioma cells to TMZ/VCR by blocking the gap junction communication between glioma cells and astrocytes via down‐regulating CX43, indicating its potential role as a novel adjuvant chemotherapeutic agent in the treatment of glioma.
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Affiliation(s)
- Shuai Zhang
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
| | - Yong Gong
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
| | - Hongxin Wang
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
| | - Zhongfan Li
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
| | - Yunfeng Huang
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
| | - Xing Fu
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
| | - Peng Xiang
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
| | - TianYu Fan
- Department of Neurosurgery, ChangSha Central Hospital, Changsha, China
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Salmina AB, Gorina YV, Erofeev AI, Balaban PM, Bezprozvanny IB, Vlasova OL. Optogenetic and chemogenetic modulation of astroglial secretory phenotype. Rev Neurosci 2021; 32:459-479. [PMID: 33550788 DOI: 10.1515/revneuro-2020-0119] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 11/28/2020] [Indexed: 12/20/2022]
Abstract
Astrocytes play a major role in brain function and alterations in astrocyte function that contribute to the pathogenesis of many brain disorders. The astrocytes are attractive cellular targets for neuroprotection and brain tissue regeneration. Development of novel approaches to monitor and to control astroglial function is of great importance for further progress in basic neurobiology and in clinical neurology, as well as psychiatry. Recently developed advanced optogenetic and chemogenetic techniques enable precise stimulation of astrocytes in vitro and in vivo, which can be achieved by the expression of light-sensitive channels and receptors, or by expression of receptors exclusively activated by designer drugs. Optogenetic stimulation of astrocytes leads to dramatic changes in intracellular calcium concentrations and causes the release of gliotransmitters. Optogenetic and chemogenetic protocols for astrocyte activation aid in extracting novel information regarding the function of brain's neurovascular unit. This review summarizes current data obtained by this approach and discusses a potential mechanistic connection between astrocyte stimulation and changes in brain physiology.
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Affiliation(s)
- Alla B Salmina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Research Institute of Molecular Medicine and Pathobiochemistry, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Yana V Gorina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Research Institute of Molecular Medicine and Pathobiochemistry, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Alexander I Erofeev
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Pavel M Balaban
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Olga L Vlasova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
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Mesnil M, Defamie N, Naus C, Sarrouilhe D. Brain Disorders and Chemical Pollutants: A Gap Junction Link? Biomolecules 2020; 11:biom11010051. [PMID: 33396565 PMCID: PMC7824109 DOI: 10.3390/biom11010051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson's disease, Alzheimer's disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson's and Alzheimer's diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.
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Affiliation(s)
- Marc Mesnil
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Norah Defamie
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Christian Naus
- Faculty of Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculté de Médecine et Pharmacie, 6 rue de La Milétrie, bât D1, TSA 51115, 86073 Poitiers, France
- Correspondence: ; Tel.: +33-5-49-45-43-58
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Perioperative Dexmedetomidine attenuates brain ischemia reperfusion injury possibly via up-regulation of astrocyte Connexin 43. BMC Anesthesiol 2020; 20:299. [PMID: 33287729 PMCID: PMC7722427 DOI: 10.1186/s12871-020-01211-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 11/25/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Astrocyte Connexin 43 (Cx43) is essential for the trophic and protective support of neurons during brain ischemia reperfusion (I/R) injury. It is believed that dexmedetomidine participates in Cx43-mediated effects. However, its mechanisms remained unclear. This study aims to address the relationship and regulation among them. METHODS Adult male Sprague-Dawley rats were allocated to the 90-min right middle cerebral arterial occlusion with or without dexmedetomidine pretreatment (5 μg/kg). Neurological functions were evaluated and brain lesions, as well as inflammatory factors (IL-1β, IL-6, TNF-α), were assessed. Ischemic penumbral cortex was harvested to determine the expression of astrocyte Cx43. Primary astrocytes were cultured to evaluate the effect of dexmedetomidine on Cx43 after oxygen-glucose deprivation. RESULTS Dexmedetomidine pretreatment attenuated neurological injury, brain lesions and expression of inflammatory factors (IL-1β, IL-6, TNF-α) after brain ischemia (P < 0.05). Astrocyte Cx43 was down-regulated by brain I/R injury, both in vivo and in vitro, which were reversed by dexmedetomidine (P < 0.05). This effect was mediated by the phosphorylation of Akt and GSK-3β. Further studies with LY294002 (PI3K inhibitor) or SB216763 (GSK-3β inhibitor) confirmed the effect of dexmedetomidine on astrocyte Cx43. CONCLUSIONS Perioperative dexmedetomidine administration attenuates neurological injury after brain I/R injury, possibly through up-regulation of astrocyte Cx43. Activation of PI3K-Akt-GSK-3β pathway might contribute to this protective effect.
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17
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Hlavac N, Guilhaume-Corrêa F, VandeVord PJ. Mechano-stimulation initiated by extracellular adhesion and cationic conductance pathways influence astrocyte activation. Neurosci Lett 2020; 739:135405. [PMID: 32979460 DOI: 10.1016/j.neulet.2020.135405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/10/2020] [Accepted: 09/21/2020] [Indexed: 11/13/2022]
Abstract
Traumatic brain injury (TBI) represents a major cause of long-term disability worldwide. Primary damage to brain tissue leads to complex secondary injury mechanisms involving inflammation, oxidative stress and cellular activation/reactivity. The molecular pathways that exacerbate brain cell dysfunction after injury are not well understood and provide challenges to developing TBI therapeutics. This study aimed to delineate mechanisms of astrocyte activation induced by mechano-stimulation, specifically involving extracellular adhesion and cationic transduction. An in vitro model was employed to investigate 2D and 3D cultures of primary astrocytes, in which cells were exposed to a single high-rate overpressure known to cause upregulation of structural and proliferative markers within 72 h of exposure. An inhibitor of focal adhesion kinase (FAK) phosphorylation, TAE226, was used to demonstrate a relationship between extracellular adhesion perturbations and structural reactivity in the novel 3D model. TAE226 mitigated upregulation of glial fibrillary acidic protein in 3D cultures by 72 h post-exposure. Alternatively, incubation with gadolinium (a cationic channel blocker) during overpressure, demonstrated a role for cationic transduction in reducing the increased levels of proliferating cell nuclear antigen that occur at 24 h post-stimulation. Furthermore, early changes in mitochondrial polarization at 15 min and in endogenous ATP levels at 4-6 h occur post-overpressure and may be linked to later changes in cell phenotype. By 24 h, there was evidence of increased amine metabolism and increased nicotinamide adenine dinucleotide phosphate oxidase (NOX4) production. The overproduction of NOX4 was counteracted by gadolinium during overpressure exposure. Altogether, the results of this study indicated that both extracellular adhesion (via FAK activation) and cationic conductance (via ion channels) contribute to early patterns of astrocyte activation following overpressure stimulation. Mechano-stimulation pathways are linked to bioenergetic and metabolic disruptions in astrocytes that influence downstream oxidative stress, aberrant proliferative capacity and structural reactivity.
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Affiliation(s)
- Nora Hlavac
- Virginia Tech, Department of Biomedical Engineering and Mechanics, Blacksburg, VA, USA
| | | | - Pamela J VandeVord
- Virginia Tech, Department of Biomedical Engineering and Mechanics, Blacksburg, VA, USA; Salem Veterans Affairs Medical Center, Department of Research, Salem, VA, USA.
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18
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Maulik M, Vasan L, Bose A, Dutta Chowdhury S, Sengupta N, Das Sarma J. Amyloid-β regulates gap junction protein connexin 43 trafficking in cultured primary astrocytes. J Biol Chem 2020; 295:15097-15111. [PMID: 32868453 DOI: 10.1074/jbc.ra120.013705] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 08/06/2020] [Indexed: 11/06/2022] Open
Abstract
Altered expression and function of astroglial gap junction protein connexin 43 (Cx43) has increasingly been associated to neurotoxicity in Alzheimer disease (AD). Although earlier studies have examined the effect of increased β-amyloid (Aβ) on Cx43 expression and function leading to neuronal damage, underlying mechanisms by which Aβ modulates Cx43 in astrocytes remain elusive. Here, using mouse primary astrocyte cultures, we have examined the cellular processes by which Aβ can alter Cx43 gap junctions. We show that Aβ25-35 impairs functional gap junction coupling yet increases hemichannel activity. Interestingly, Aβ25-35 increased the intracellular pool of Cx43 with a parallel decrease in gap junction assembly at the surface. Intracellular Cx43 was found to be partly retained in the endoplasmic reticulum-associated cell compartments. However, forward trafficking of the newly synthesized Cx43 that already reached the Golgi was not affected in Aβ25-35-exposed astrocytes. Supporting this, treatment with 4-phenylbutyrate, a well-known chemical chaperone that improves trafficking of several transmembrane proteins, restored Aβ-induced impaired gap junction coupling between astrocytes. We further show that interruption of Cx43 endocytosis in Aβ25-35-exposed astrocytes resulted in their retention at the cell surface in the form of functional gap junctions indicating that Aβ25-35 causes rapid internalization of Cx43 gap junctions. Additionally, in silico molecular docking suggests that Aβ can bind favorably to Cx43. Our study thus provides novel insights into the cellular mechanisms by which Aβ modulates Cx43 function in astrocytes, the basic understanding of which is vital for the development of alternative therapeutic strategy targeting connexin channels in AD.
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Affiliation(s)
- Mahua Maulik
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
| | - Lakshmy Vasan
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Abhishek Bose
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Saikat Dutta Chowdhury
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Neelanjana Sengupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Jayasri Das Sarma
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
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Debarba LK, Marangon PB, Borges BC, Veida-Silva H, Venâncio JC, Almeida-Pereira G, Antunes-Rodrigues J, Elias LLK. Neonatal nutritional programming induces gliosis and alters the expression of T-cell protein tyrosine phosphatase and connexins in male rats. Horm Behav 2020; 120:104690. [PMID: 31954709 DOI: 10.1016/j.yhbeh.2020.104690] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 12/20/2019] [Accepted: 01/12/2020] [Indexed: 01/17/2023]
Abstract
Changes to neonatal nutrition result in long-lasting impairments in energy balance, which may be described as metabolic programing. Astrocytes, which are interconnected by gap junctions, have emerged as important players in the hypothalamic control of food intake. In order to study the effects of nutritional programming on glial morphology and protein expression, cross-fostered male Wistar rats at postnatal day 3 were assigned to three groups based on litter size: small litter (3 pups per dam, SL), normal litter (10 pups per dam, NL), and large litter (16 pups per dam, LL). Rats from the SL group exhibited higher body weight throughout the study and hyperphagia after weaning. LL animals exhibited hyperphagia, high energy efficiency and catch-up of body weight after weaning. Both the SL and LL groups at postnatal day 60 (PN60) exhibited increased levels of plasma leptin, the Lee index (as an index of obesity), adiposity content, immunoreactivity toward T-cell protein tyrosine phosphatase (TCPTP), and glial fibrillary acidic protein (GFAP) in the arcuate nucleus (ARC) of the hypothalamus. Astrocyte morphology was altered in the ARC of SL and LL animals, and this effect occurred in parallel with a reduction in immunoreactivity toward connexin 30 (CX30). The data obtained demonstrate that both neonatal over- and underfeeding promote not only alterations in the metabolic status but also morphological changes in glial cells in parallel with increasing TCPTP and changes in connexin expression.
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Affiliation(s)
- Lucas Kniess Debarba
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900.
| | - Paula Beatriz Marangon
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900
| | - Beatriz C Borges
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900
| | - Hellen Veida-Silva
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900
| | - Jade Cabestre Venâncio
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900
| | - Gislaine Almeida-Pereira
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900
| | - José Antunes-Rodrigues
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900
| | - Lucila Leico Kagohara Elias
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil. 14049-900
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Lagos-Cabré R, Burgos-Bravo F, Avalos AM, Leyton L. Connexins in Astrocyte Migration. Front Pharmacol 2020; 10:1546. [PMID: 32009957 PMCID: PMC6974553 DOI: 10.3389/fphar.2019.01546] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
Astrocytes have long been considered the supportive cells of the central nervous system, but during the last decades, they have gained much more attention because of their active participation in the modulation of neuronal function. For example, after brain damage, astrocytes become reactive and undergo characteristic morphological and molecular changes, such as hypertrophy and increase in the expression of glial fibrillary acidic protein (GFAP), in a process known as astrogliosis. After severe damage, astrocytes migrate to the lesion site and proliferate, which leads to the formation of a glial scar. At this scar-forming stage, astrocytes secrete many factors, such as extracellular matrix proteins, cytokines, growth factors and chondroitin sulfate proteoglycans, stop migrating, and the process is irreversible. Although reactive gliosis is a normal physiological response that can protect brain cells from further damage, it also has detrimental effects on neuronal survival, by creating a hostile and non-permissive environment for axonal repair. The transformation of astrocytes from reactive to scar-forming astrocytes highlights migration as a relevant regulator of glial scar formation, and further emphasizes the importance of efficient communication between astrocytes in order to orchestrate cell migration. The coordination between astrocytes occurs mainly through Connexin (Cx) channels, in the form of direct cell-cell contact (gap junctions, GJs) or contact between the extracellular matrix and the astrocytes (hemichannels, HCs). Reactive astrocytes increase the expression levels of several proteins involved in astrocyte migration, such as αvβ3 Integrin, Syndecan-4 proteoglycan, the purinergic receptor P2X7, Pannexin1, and Cx43 HCs. Evidence has indicated that Cx43 HCs play a role in regulating astrocyte migration through the release of small molecules to the extracellular space, which then activate receptors in the same or adjacent cells to continue the signaling cascades required for astrocyte migration. In this review, we describe the communication of astrocytes through Cxs, the role of Cxs in inflammation and astrocyte migration, and discuss the molecular mechanisms that regulate Cx43 HCs, which may provide a therapeutic window of opportunity to control astrogliosis and the progression of neurodegenerative diseases.
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Affiliation(s)
- Raúl Lagos-Cabré
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Francesca Burgos-Bravo
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Ana María Avalos
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Lisette Leyton
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
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Early life exposure to cortisol in zebrafish (Danio rerio): similarities and differences in behaviour and physiology between larvae of the AB and TL strains. Behav Pharmacol 2020; 30:260-271. [PMID: 30724799 DOI: 10.1097/fbp.0000000000000470] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Maternal stress and early life stress affect development. Zebrafish (Danio rerio) are ideally suited to study this, as embryos develop externally into free-feeding larvae. The objective of this study was therefore to assess the effects of increased levels of cortisol, mimicking thereby maternal stress, on larval physiology and behaviour. We studied the effects in two common zebrafish strains, that is, AB and Tupfel long-fin (TL), to assess strain dependency of effects. Fertilized eggs were exposed to a cortisol-containing medium (1.1 μmol/l) or control medium from 0 to 6 h following fertilization, after which at 5-day following fertilization, larval behaviour and baseline hypothalamus-pituitary-interrenal cells axis functioning were measured. The data confirmed earlier observed differences between AB larvae and TL larvae: a lower hypothalamus-pituitary-interrenal axis activity in TL larvae than AB larvae, and slower habituation to repeated acoustic/vibrational stimuli in TL larvae than AB larvae. Following cortisol treatment, increased baseline levels of cortisol were found in AB larvae but not TL larvae. At the behavioural level, increased thigmotaxis or 'wall hugging' was found in AB larvae, but decreased thigmotaxis in TL larvae; however, both AB larvae and TL larvae showed decreased habituation to repeated acoustic/vibrational stimuli. The data emphasize that strain is a critical factor in zebrafish research. The habituation data suggest a robust effect of cortisol exposure, which is likely an adaptive response to increase the likelihood of detecting or responding to potentially threatening stimuli. This may enhance early life survival. Along with other studies, our study underlines the notion that zebrafish may be a powerful model animal to study the effects of maternal and early life stress on life history.
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Ahmad SF, Nadeem A, Ansari MA, Bakheet SA, Alasmari F, Alasmari AF, Al-Kharashi LA, Al-Qahtani Q, Attia SM. The potent immunomodulatory compound VGX-1027 regulates inflammatory mediators in CD4+ T cells, which are concomitant with the prevention of neuroimmune dysregulation in BTBR T+ Itpr3tf/J mice. Life Sci 2019; 237:116930. [DOI: 10.1016/j.lfs.2019.116930] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 10/01/2019] [Accepted: 10/02/2019] [Indexed: 12/14/2022]
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Predicting Reactive Astrogliosis Propagation by Bayesian Computational Modeling: the Repeater Stations Model. Mol Neurobiol 2019; 57:879-895. [PMID: 31522382 DOI: 10.1007/s12035-019-01749-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/26/2019] [Indexed: 10/26/2022]
Abstract
Reactive astrogliosis occurs upon focal brain injury and in neurodegenerative diseases. The mechanisms that propagate reactive astrogliosis to distal parts of the brain, in a rapid wave that activates astrocytes and other cell types along the way, are not completely understood. It is proposed that damage-associated molecular patterns (DAMP) released by necrotic cells from the injury core have a major role in the reactive astrogliosis initiation but whether they also participate in reactive astrogliosis propagation remains to be determined. We here developed a Bayesian computational model to define the most probable model for reactive astrogliosis propagation. Starting with experimental data from GFAP-immunostained reactive astrocytes, we defined five types of astrocytes based on morphometrical cues and registered the position of each reactive astrocyte cell type in the hemisphere ipsilateral to the injured site after 3 and 7 days post-ischemia. We developed equations for the changes in DAMP concentration (due to diffusion, binding to receptors or degradation), soluble mediators secretion, and for the evolution reactive astrogliosis. We tested four predefined models based on abovementioned previous hypothesis and modifications to it. Our results showed that DAMP diffusion alone has not justified the reactive astrogliosis propagation as previously assumed. Only two models succeeded in accurately reproducing the experimentally measured data and they highlighted the role of microglia and the glial secretion of soluble mediators to sustain the reactive signal and activating neighboring astrocytes. Thus, our in silico analysis proposes that glial cells behave as repeater stations of the injury signal in order to propagate reactive astrogliosis.
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Magni G, Boccazzi M, Bodini A, Abbracchio MP, van den Maagdenberg AMJM, Ceruti S. Basal astrocyte and microglia activation in the central nervous system of Familial Hemiplegic Migraine Type I mice. Cephalalgia 2019; 39:1809-1817. [DOI: 10.1177/0333102419861710] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background Gain-of-function missense mutations in the α1A subunit of neuronal CaV2.1 channels, which define Familial Hemiplegic Migraine Type 1 (FHM1), result in enhanced cortical glutamatergic transmission and a higher susceptibility to cortical spreading depolarization. It is now well established that neurons signal to surrounding glial cells, namely astrocytes and microglia, in the central nervous system, which in turn become activated and in pathological conditions can sustain neuroinflammation. We and others previously demonstrated an increased activation of pro-algogenic pathways, paralleled by augmented macrophage infiltration, in both isolated trigeminal ganglia and mixed trigeminal ganglion neuron-satellite glial cell cultures of FHM1 mutant mice. Hence, we hypothesize that astrocyte and microglia activation may occur in parallel in the central nervous system. Methods We have evaluated signs of reactive glia in brains from naïve FHM1 mutant mice in comparison with wild type animals by immunohistochemistry and Western blotting. Results Here we show for the first time signs of reactive astrogliosis and microglia activation in the naïve FHM1 mutant mouse brain. Conclusions Our data reinforce the involvement of glial cells in migraine, and suggest that modulating such activation may represent an innovative approach to reduce pathology.
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Affiliation(s)
- Giulia Magni
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, Milan, Italy
| | - Marta Boccazzi
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, Milan, Italy
| | - Antonella Bodini
- Institute for Applied Mathematics and Information Technologies “Enrico Magenes”, National Research Council, Milan, Italy
| | - Maria P Abbracchio
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, Milan, Italy
| | | | - Stefania Ceruti
- Department of Pharmacological and Biomolecular Sciences (DiSFeB), Università degli Studi di Milano, Milan, Italy
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Köles L, Szepesy J, Berekméri E, Zelles T. Purinergic Signaling and Cochlear Injury-Targeting the Immune System? Int J Mol Sci 2019; 20:ijms20122979. [PMID: 31216722 PMCID: PMC6627352 DOI: 10.3390/ijms20122979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023] Open
Abstract
Hearing impairment is the most common sensory deficit, affecting more than 400 million people worldwide. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy largely due to the insufficient knowledge of the pathomechanism. Purinergic signaling plays a substantial role in cochlear (patho)physiology. P2 (ionotropic P2X and the metabotropic P2Y) as well as adenosine receptors expressed on cochlear sensory and non-sensory cells are involved mostly in protective mechanisms of the cochlea. They are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics. Cochlear blood flow is also regulated by purines. Here, we propose to comprehend this field with the purine-immune interactions in the cochlea. The role of harmful immune mechanisms in sensorineural hearing losses has been emerging in the horizon of cochlear pathologies. In addition to decreasing hearing sensitivity and increasing cochlear blood supply, influencing the immune system can be the additional avenue for pharmacological targeting of purinergic signaling in the cochlea. Elucidating this complexity of purinergic effects on cochlear functions is necessary and it can result in development of new therapeutic approaches in hearing disabilities, especially in the noise-induced ones.
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Affiliation(s)
- László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Ecology, University of Veterinary Medicine, H-1078 Budapest, Hungary.
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary.
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26
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Yang XL, Wang X, Shao L, Jiang GT, Min JW, Mei XY, He XH, Liu WH, Huang WX, Peng BW. TRPV1 mediates astrocyte activation and interleukin-1β release induced by hypoxic ischemia (HI). J Neuroinflammation 2019; 16:114. [PMID: 31142341 PMCID: PMC6540554 DOI: 10.1186/s12974-019-1487-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 04/25/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Hypoxic-ischemic encephalopathy (HIE) is a serious birth complication with high incidence in both advanced and developing countries. Children surviving from HIE often have severe long-term sequela including cerebral palsy, epilepsy, and cognitive disabilities. The severity of HIE in infants is tightly associated with increased IL-1β expression and astrocyte activation which was regulated by transient receptor potential vanilloid 1 (TRPV1), a non-selective cation channel in the TRP family. METHODS Neonatal hypoxic ischemia (HI) and oxygen-glucose deprivation (OGD) were used to simulate HIE in vivo and in vitro. Primarily cultured astrocytes were used for investigating the expression of glial fibrillary acidic protein (GFAP), IL-1β, Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), and activation of the nucleotide-binding, oligomerization domain (NOD)-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome by using Western blot, q-PCR, and immunofluorescence. Brain atrophy, infarct size, and neurobehavioral disorders were evaluated by Nissl staining, 2,3,5-triphenyltetrazolium chloride monohydrate (TTC) staining and neurobehavioral tests (geotaxis reflex, cliff aversion reaction, and grip test) individually. RESULTS Astrocytes were overactivated after neonatal HI and OGD challenge. The number of activated astrocytes, the expression level of IL-1β, brain atrophy, and shrinking infarct size were all downregulated in TRPV1 KO mice. TRPV1 deficiency in astrocytes attenuated the expression of GFAP and IL-1β by reducing phosphorylation of JAK2 and STAT3. Meanwhile, IL-1β release was significantly reduced in TRPV1 deficiency astrocytes by inhibiting activation of NLRP3 inflammasome. Additionally, neonatal HI-induced neurobehavioral disorders were significantly improved in the TRPV1 KO mice. CONCLUSIONS TRPV1 promotes activation of astrocytes and release of astrocyte-derived IL-1β mainly via JAK2-STAT3 signaling and activation of the NLRP3 inflammasome. Our findings provide mechanistic insights into TRPV1-mediated brain damage and neurobehavioral disorders caused by neonatal HI and potentially identify astrocytic TRPV1 as a novel therapeutic target for treating HIE in the subacute stages (24 h).
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Affiliation(s)
- Xing-Liang Yang
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China
| | - Xin Wang
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China
| | - Lin Shao
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China
| | - Guang-Tong Jiang
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China
| | - Jia-Wei Min
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China
| | - Xi-Yu Mei
- No.1 Middle School affiliated to Central China Normal University, Wuhan, China
| | - Xiao-Hua He
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Wan-Hong Liu
- Department of Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Wen-Xian Huang
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China. .,Department of Pathology, Renmin Hospital of Wuhan University, Jiefang Rd238#, Wuhan, 430071, Hubei, China.
| | - Bi-Wen Peng
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China.
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Díaz EF, Labra VC, Alvear TF, Mellado LA, Inostroza CA, Oyarzún JE, Salgado N, Quintanilla RA, Orellana JA. Connexin 43 hemichannels and pannexin-1 channels contribute to the α-synuclein-induced dysfunction and death of astrocytes. Glia 2019; 67:1598-1619. [PMID: 31033038 DOI: 10.1002/glia.23631] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 01/22/2023]
Abstract
Diverse studies have suggested that cytoplasmic inclusions of misfolded α-synuclein in neuronal and glial cells are main pathological features of different α-synucleinopathies, including Parkinson's disease and dementia with Lewy bodies. Up to now, most studies have focused on the effects of α-synuclein on neurons, whereas the possible alterations of astrocyte functions and neuron-glia crosstalk have received minor attention. Recent evidence indicates that cellular signaling mediated by hemichannels and pannexons is critical for astroglial function and dysfunction. These channels constitute a diffusional route of communication between the cytosol and the extracellular space and during pathological scenarios they may lead to homeostatic disturbances linked to the pathogenesis and progression of different diseases. Here, we found that α-synuclein enhances the opening of connexin 43 (Cx43) hemichannels and pannexin-1 (Panx1) channels in mouse cortical astrocytes. This response was linked to the activation of cytokines, the p38 MAP kinase, the inducible nitric oxide synthase, cyclooxygenase 2, intracellular free Ca2+ concentration ([Ca2+ ]i ), and purinergic and glutamatergic signaling. Relevantly, the α-synuclein-induced opening of hemichannels and pannexons resulted in alterations in [Ca2+ ]i dynamics, nitric oxide (NO) production, gliotransmitter release, mitochondrial morphology, and astrocyte survival. We propose that α-synuclein-mediated opening of astroglial Cx43 hemichannels and Panx1 channels might constitute a novel mechanism involved in the pathogenesis and progression of α-synucleinopathies.
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Affiliation(s)
- Esteban F Díaz
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valeria C Labra
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tanhia F Alvear
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis A Mellado
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carla A Inostroza
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan E Oyarzún
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicole Salgado
- Unidad de Microscopía Avanzada UC, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo A Quintanilla
- Escuela de Medicina, Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes (CIAA), Santiago, Chile.,Laboratory of Neurodegenerative Diseases, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Escuela de Medicina, Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes (CIAA), Santiago, Chile
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Matias I, Morgado J, Gomes FCA. Astrocyte Heterogeneity: Impact to Brain Aging and Disease. Front Aging Neurosci 2019; 11:59. [PMID: 30941031 PMCID: PMC6433753 DOI: 10.3389/fnagi.2019.00059] [Citation(s) in RCA: 220] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/01/2019] [Indexed: 12/13/2022] Open
Abstract
Astrocytes, one of the largest glial cell population in the central nervous system (CNS), play a key function in several events of brain development and function, such as synapse formation and function, control of neurotransmitters release and uptake, production of trophic factors and control of neuronal survival. Initially described as a homogenous population, several evidences have pointed that astrocytes are highly heterogeneous, both morphologically and functionally, within the same region, and across different brain regions. Recent findings suggest that the heterogeneity in the expression profile of proteins involved in astrocyte function may predict the selective vulnerability of brain regions to specific diseases, as well as to the age-related cognitive decline. However, the molecular mechanisms underlying these changes, either in aging as well as in brain disease are scarce. Neuroinflammation, a hallmark of several neurodegenerative diseases and aging, is reported to have a dubious impact on glial activation, as these cells release pro- and anti-inflammatory cytokines and chemokines, anti-oxidants, free radicals, and neurotrophic factors. Despite the emerging evidences supporting that reactive astrocytes have a duality in their phenotype, neurotoxic or neuroprotective properties, depending on the age and stimuli, the underlying mechanisms of their activation, cellular interplays and the impact of regional astrocyte heterogeneity are still a matter of discussion. In this review article, we will summarize recent findings on astrocyte heterogeneity and phenotypes, as well as their likely impact for the brain function during aging and neural diseases. We will focus on the molecules and mechanisms triggered by astrocyte to control synapse formation in different brain regions. Finally, we will discuss new evidences on how the modulation of astrocyte phenotype and function could impact the synaptic deficits and glial dysfunction present in aging and pathological states.
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Affiliation(s)
- Isadora Matias
- Laboratory of Cellular Neurobiology, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Juliana Morgado
- Laboratory of Cellular Neurobiology, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Flávia Carvalho Alcantara Gomes
- Laboratory of Cellular Neurobiology, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Debarba LK, Vechiato FMV, Veida-Silva H, Borges BC, Jamur MC, Antunes-Rodrigues J, Elias LLK. The role of TCPTP on leptin effects on astrocyte morphology. Mol Cell Endocrinol 2019; 482:62-69. [PMID: 30572001 DOI: 10.1016/j.mce.2018.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 11/25/2018] [Accepted: 12/15/2018] [Indexed: 12/19/2022]
Abstract
Leptin and LPS has been implicated in the development of hypothalamic astrogliosis in rodents. Astrocytes, which are interconnected by gap junction proteins, have emerged as important players in the control of energy homeostasis exerted by the hypothalamus. To investigate the hypothesis of action of T-cell protein tyrosine phosphatase (TCPTP) on the astrocyte morphology, astrocytes from the hypothalamus of one-day-old rats were stimulated with leptin and LPS (used as a positive control). Leptin and LPS induced a marked increase in astrocyte size, an increase in Ptpn2 (TCPTP gene) and gap junction alpha-1 protein, - Gja1 (connexin 43 - CX43 gene) mRNA expression and a decrease in gap junction protein, alpha 6 - Gja6 (CX30 gene) mRNA expression. Remarkably, these effects on astrocytes morphology and connexins were prevented by Ptpn2 siRNA. Astrocytes are known to produce cytokines; here we show that TCPTP acts as an important regulator of the cytokines and it possesses a reciprocal interplay with protein tyrosine phosphatase 1B (PTP1B). Our findings demonstrate that leptin and LPS alter astrocyte morphology by increasing TCPTP, which in turn modulates connexin 30 (CX30) and connexin 43 (CX43) expression. TCPTP and PTP1B seem to act in the regulation of cytokine production in astrocytes.
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Affiliation(s)
- Lucas Kniess Debarba
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil.
| | | | - Hellen Veida-Silva
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
| | - Beatriz C Borges
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
| | - Maria Célia Jamur
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, 14049-900, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
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30
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Berekméri E, Szepesy J, Köles L, Zelles T. Purinergic signaling in the organ of Corti: Potential therapeutic targets of sensorineural hearing losses. Brain Res Bull 2019; 151:109-118. [PMID: 30721767 DOI: 10.1016/j.brainresbull.2019.01.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/10/2019] [Accepted: 01/25/2019] [Indexed: 01/04/2023]
Abstract
Purinergic signaling is deeply involved in the development, functions and protective mechanisms of the cochlea. Release of ATP and activation of purinergic receptors on sensory and supporting/epithelial cells play a substantial role in cochlear (patho)physiology. Both the ionotropic P2X and the metabotropic P2Y receptors are widely distributed on the inner and outer hair cells as well as on the different supporting cells in the organ of Corti and on other epithelial cells in the scala media. Among others, they are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics acting on outer hair cells and supporting cells. Cochlear blood flow is also regulated by purines. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy. Decreasing hearing sensitivity and increasing cochlear blood supply by pharmacological targeting of purinergic signaling in the cochlea are potential new therapeutic approaches in these hearing disabilities, especially in the noise-induced ones.
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Affiliation(s)
- Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary; Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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31
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Sáez JC, Contreras-Duarte S, Gómez GI, Labra VC, Santibañez CA, Gajardo-Gómez R, Avendaño BC, Díaz EF, Montero TD, Velarde V, Orellana JA. Connexin 43 Hemichannel Activity Promoted by Pro-Inflammatory Cytokines and High Glucose Alters Endothelial Cell Function. Front Immunol 2018; 9:1899. [PMID: 30158937 PMCID: PMC6104120 DOI: 10.3389/fimmu.2018.01899] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022] Open
Abstract
The present work was done to elucidate whether hemichannels of a cell line derived from endothelial cells are affected by pro-inflammatory conditions (high glucose and IL-1β/TNF-α) known to lead to vascular dysfunction. We used EAhy 926 cells treated with high glucose and IL-1β/TNF-α. The hemichannel activity was evaluated with the dye uptake method and was abrogated with selective inhibitors or knocking down of hemichannel protein subunits with siRNA. Western blot analysis, cell surface biotinylation, and confocal microscopy were used to evaluate total and plasma membrane amounts of specific proteins and their cellular distribution, respectively. Changes in intracellular Ca2+ and nitric oxide (NO) signals were estimated by measuring FURA-2 and DAF-FM probes, respectively. High glucose concentration was found to elevate dye uptake, a response that was enhanced by IL-1β/TNF-α. High glucose plus IL-1β/TNF-α-induced dye uptake was abrogated by connexin 43 (Cx43) but not pannexin1 knockdown. Furthermore, Cx43 hemichannel activity was associated with enhanced ATP release and activation of p38 MAPK, inducible NO synthase, COX2, PGE2 receptor EP1, and P2X7/P2Y1 receptors. Inhibition of the above pathways prevented completely the increase in Cx43 hemichannel activity of cells treated high glucose and IL-1β/TNF-α. Both synthetic and endogenous cannabinoids (CBs) also prevented the increment in Cx43 hemichannel opening, as well as the subsequent generation and release of ATP and NO induced by pro-inflammatory conditions. The counteracting action of CBs also was extended to other endothelial alterations evoked by IL-1β/TNF-α and high glucose, including increased ATP-dependent Ca2+ dynamics and insulin-induced NO production. Finally, inhibition of Cx43 hemichannels also prevented the ATP release from endothelial cells treated with IL-1β/TNF-α and high glucose. Therefore, we propose that reduction of hemichannel activity could represent a strategy against the activation of deleterious pathways that lead to endothelial dysfunction and possibly cell damage evoked by high glucose and pro-inflammatory conditions during cardiovascular diseases.
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Affiliation(s)
- Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Susana Contreras-Duarte
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile.,Departamento de Ginecología y Obstetricia, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Gonzalo I Gómez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valeria C Labra
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Cristian A Santibañez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rosario Gajardo-Gómez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Beatriz C Avendaño
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Esteban F Díaz
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Trinidad D Montero
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Victoria Velarde
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Hoorelbeke D, Decrock E, Van Haver V, De Bock M, Leybaert L. Calcium, a pivotal player in photodynamic therapy? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1805-1814. [PMID: 30076858 DOI: 10.1016/j.bbamcr.2018.07.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/28/2018] [Accepted: 07/30/2018] [Indexed: 02/06/2023]
Abstract
Photodynamic therapy combines three non-toxic components: light, oxygen and a photosensitizer to generate singlet oxygen and/or other ROS molecules in order to target destruction of cancer cells. The damage induced in the targeted cells can furthermore propagate to non-exposed bystander cells thereby exacerbating the damage. Ca2+ signaling is strongly intertwined with ROS signaling and both play crucial roles in cell death. In this review we aimed to review current knowledge on the role of Ca2+ and ROS signaling, their effect on cell-cell propagation via connexin-linked mechanisms and the outcome in terms of cell death. In general, photodynamic therapy results in an increased cytosolic Ca2+ concentration originating from Ca2+ entry or Ca2+ release from internal stores. While photodynamic therapy can certainly induce cell death, the outcome depends on the cell type and the photosensitizer used. Connexin channels propagating the Ca2+ signal, and presumably regenerating ROS at distance, may play a role in spreading the effect to neighboring non-exposed bystander cells. Given the various cell types and photosensitizers used, there is currently no unified signaling scheme to explain the role of Ca2+ and connexins in the responses following photodynamic therapy. This article is part of a Special Issue entitled: Calcium signaling in health, disease and therapy edited by Geert Bultynck and Jan Parys.
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Affiliation(s)
| | - Elke Decrock
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium
| | - Valérie Van Haver
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium
| | - Marijke De Bock
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium
| | - Luc Leybaert
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium.
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Glucocorticoid receptor in astrocytes regulates midbrain dopamine neurodegeneration through connexin hemichannel activity. Cell Death Differ 2018; 26:580-596. [PMID: 30006609 PMCID: PMC6370798 DOI: 10.1038/s41418-018-0150-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 05/20/2018] [Accepted: 05/28/2018] [Indexed: 01/24/2023] Open
Abstract
The precise contribution of astrocytes in neuroinflammatory process occurring in Parkinson’s disease (PD) is not well characterized. In this study, using GRCx30CreERT2 mice that are conditionally inactivated for glucocorticoid receptor (GR) in astrocytes, we have examined the actions of astrocytic GR during dopamine neuron (DN) degeneration triggered by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The results show significantly augmented DN loss in GRCx30CreERT2 mutant mice in substantia nigra (SN) compared to controls. Hypertrophy of microglia but not of astrocytes was greatly enhanced in SN of these astrocytic GR mutants intoxicated with MPTP, indicating heightened microglial reactivity compared to similarly-treated control mice. In the SN of GR astrocyte mutants, specific inflammation-associated transcripts ICAM-1, TNF-α and Il-1β as well as TNF-α protein levels were significantly elevated after MPTP neurotoxicity compared to controls. Interestingly, this paralleled increased connexin hemichannel activity and elevated intracellular calcium levels in astrocytes examined in acute midbrain slices from control and mutant mice treated with MPP+ . The increased connexin-43 hemichannel activity was found in vivo in MPTP-intoxicated mice. Importantly, treatment of MPTP-injected GRCx30CreERT2 mutant mice with TAT-Gap19 peptide, a specific connexin-43 hemichannel blocker, reverted both DN loss and microglial activation; in wild-type mice there was partial but significant survival effect. In the SN of post-mortem PD patients, a significant decrease in the number of astrocytes expressing nuclear GR was observed, suggesting the participation of astrocytic GR deregulation of inflammatory process in PD. Overall, these data provide mechanistic insights into GR-modulated processes in vivo, specifically in astrocytes, that contribute to a pro-inflammatory state and dopamine neurodegeneration in PD pathology.
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Sompol P, Norris CM. Ca 2+, Astrocyte Activation and Calcineurin/NFAT Signaling in Age-Related Neurodegenerative Diseases. Front Aging Neurosci 2018; 10:199. [PMID: 30038565 PMCID: PMC6046440 DOI: 10.3389/fnagi.2018.00199] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/12/2018] [Indexed: 12/12/2022] Open
Abstract
Mounting evidence supports a fundamental role for Ca2+ dysregulation in astrocyte activation. Though the activated astrocyte phenotype is complex, cell-type targeting approaches have revealed a number of detrimental roles of activated astrocytes involving neuroinflammation, release of synaptotoxic factors and loss of glutamate regulation. Work from our lab and others has suggested that the Ca2+/calmodulin dependent protein phosphatase, calcineurin (CN), provides a critical link between Ca2+ dysregulation and the activated astrocyte phenotype. A proteolyzed, hyperactivated form of CN appears at high levels in activated astrocytes in both human tissue and rodent tissue around regions of amyloid and vascular pathology. Similar upregulation of the CN-dependent transcription factor nuclear factor of activated T cells (NFAT4) also appears in activated astrocytes in mouse models of Alzheimer's disease (ADs) and traumatic brain injury (TBI). Major consequences of hyperactivated CN/NFAT4 signaling in astrocytes are neuroinflammation, synapse dysfunction and glutamate dysregulation/excitotoxicity, which will be covered in this review article.
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Affiliation(s)
- Pradoldej Sompol
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, United States.,Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, United States
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Walrave L, Pierre A, Albertini G, Aourz N, De Bundel D, Van Eeckhaut A, Vinken M, Giaume C, Leybaert L, Smolders I. Inhibition of astroglial connexin43 hemichannels with TAT-Gap19 exerts anticonvulsant effects in rodents. Glia 2018; 66:1788-1804. [PMID: 29683209 DOI: 10.1002/glia.23341] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 04/04/2018] [Accepted: 04/04/2018] [Indexed: 12/14/2022]
Abstract
Accumulating evidence shows a key function for astrocytic connexin43 (Cx43) signaling in epilepsy. However, the lack of experimental distinction between Cx43 gap junction channels (GJCs) and hemichannels (HCs) has impeded the identification of the exact contribution of either channel configurations to epilepsy. We therefore investigated whether TAT-Gap19, a Cx mimetic peptide that inhibits Cx43 HCs but not the corresponding Cx43 GJCs, influences experimentally induced seizures in rodents. Dye uptake experiments in acute hippocampal slices of mice demonstrated that astroglial Cx43 HCs open in response to the chemoconvulsant pilocarpine and this was inhibited by TAT-Gap19. In vivo, pilocarpine-induced seizures as well as the accompanying increase in D-serine microdialysate levels were suppressed by Cx43 HC inhibition. Moreover, the anticonvulsant action of TAT-Gap19 was reversed by exogenous D-serine administration, suggesting that Cx43 HC inhibition protects against seizures by lowering extracellular D-serine levels. The anticonvulsive properties of Cx43 HC inhibition were further confirmed in electrical seizure mouse models, i.e. an acute 6 Hertz (Hz) model of refractory seizures and a chronic 6 Hz corneal kindling model. Collectively, these results indicate that Cx43 HCs play a role in seizures and underscore their potential as a novel and druggable target in epilepsy treatment.
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Affiliation(s)
- Laura Walrave
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Anouk Pierre
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Najat Aourz
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Ann Van Eeckhaut
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, 75005, France
| | - Luc Leybaert
- Physiology group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, 1090, Belgium
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Biswas J, Gupta S, Verma DK, Gupta P, Singh A, Tiwari S, Goswami P, Sharma S, Singh S. Involvement of glucose related energy crisis and endoplasmic reticulum stress: Insinuation of streptozotocin induced Alzheimer's like pathology. Cell Signal 2018; 42:211-226. [DOI: 10.1016/j.cellsig.2017.10.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/05/2017] [Accepted: 10/30/2017] [Indexed: 11/24/2022]
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 899] [Impact Index Per Article: 149.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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Ren Q, Wang ZZ, Chu SF, Xia CY, Chen NH. Gap junction channels as potential targets for the treatment of major depressive disorder. Psychopharmacology (Berl) 2018; 235:1-12. [PMID: 29178009 DOI: 10.1007/s00213-017-4782-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 11/05/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Major depressive disorder (MDD) remains a major public health problem worldwide. The association between MDD and the dysfunction of gap junction channels (GJCs) in glial cells, especially astrocytes, is still controversial. OBJECTIVE This review provides an overview of the role of astrocyte GJCs in LMDD. RESULTS Exposure to chronic unpredictable stress caused a reduction in connexin expression in the rat prefrontal cortex, a result that is consistent with clinical findings reported in postmortem studies of brains from MDD patients. Chronic antidepressant treatment in these rats increased the expression of connexins. However, pharmacological GJC blockade in normal rodents decreased connexin expression and caused depressive-like behaviors. Furthermore, GJC dysfunction affects electrical conductance, metabolic coupling and secondary messengers, and inflammatory responses, which are consistent with current hypotheses on MDD. All these results provide a comprehensive overview of the neurobiology of MDD. CONCLUSION This review supports the hypothesis that the regulation of GJCs between astrocytes could be an underlying mechanism for the therapeutic effect of antidepressants.
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Affiliation(s)
- Qian Ren
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Shi-Feng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Cong-Yuan Xia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China. .,College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.
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40
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Leybaert L, Lampe PD, Dhein S, Kwak BR, Ferdinandy P, Beyer EC, Laird DW, Naus CC, Green CR, Schulz R. Connexins in Cardiovascular and Neurovascular Health and Disease: Pharmacological Implications. Pharmacol Rev 2017; 69:396-478. [PMID: 28931622 PMCID: PMC5612248 DOI: 10.1124/pr.115.012062] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication. In the central nervous system they form cellular syncytia and coordinate neural function. Gap junction channels are normally open and hemichannels are normally closed, but pathologic conditions may restrict gap junction communication and promote hemichannel opening, thereby disturbing a delicate cellular communication balance. Until recently, most connexin-targeting agents exhibited little specificity and several off-target effects. Recent work with peptide-based approaches has demonstrated improved specificity and opened avenues for a more rational approach toward independently modulating the function of gap junctions and hemichannels. We here review the role of connexins and their channels in cardiovascular and neurovascular health and disease, focusing on crucial regulatory aspects and identification of potential targets to modify their function. We conclude that peptide-based investigations have raised several new opportunities for interfering with connexins and their channels that may soon allow preservation of gap junction communication, inhibition of hemichannel opening, and mitigation of inflammatory signaling.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Paul D Lampe
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Stefan Dhein
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Brenda R Kwak
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Peter Ferdinandy
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Eric C Beyer
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Dale W Laird
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Christian C Naus
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Colin R Green
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
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Charvériat M, Naus CC, Leybaert L, Sáez JC, Giaume C. Connexin-Dependent Neuroglial Networking as a New Therapeutic Target. Front Cell Neurosci 2017; 11:174. [PMID: 28694772 PMCID: PMC5483454 DOI: 10.3389/fncel.2017.00174] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 06/08/2017] [Indexed: 12/12/2022] Open
Abstract
Astrocytes and neurons dynamically interact during physiological processes, and it is now widely accepted that they are both organized in plastic and tightly regulated networks. Astrocytes are connected through connexin-based gap junction channels, with brain region specificities, and those networks modulate neuronal activities, such as those involved in sleep-wake cycle, cognitive, or sensory functions. Additionally, astrocyte domains have been involved in neurogenesis and neuronal differentiation during development; they participate in the “tripartite synapse” with both pre-synaptic and post-synaptic neurons by tuning down or up neuronal activities through the control of neuronal synaptic strength. Connexin-based hemichannels are also involved in those regulations of neuronal activities, however, this feature will not be considered in the present review. Furthermore, neuronal processes, transmitting electrical signals to chemical synapses, stringently control astroglial connexin expression, and channel functions. Long-range energy trafficking toward neurons through connexin-coupled astrocytes and plasticity of those networks are hence largely dependent on neuronal activity. Such reciprocal interactions between neurons and astrocyte networks involve neurotransmitters, cytokines, endogenous lipids, and peptides released by neurons but also other brain cell types, including microglial and endothelial cells. Over the past 10 years, knowledge about neuroglial interactions has widened and now includes effects of CNS-targeting drugs such as antidepressants, antipsychotics, psychostimulants, or sedatives drugs as potential modulators of connexin function and thus astrocyte networking activity. In physiological situations, neuroglial networking is consequently resulting from a two-way interaction between astrocyte gap junction-mediated networks and those made by neurons. As both cell types are modulated by CNS drugs we postulate that neuroglial networking may emerge as new therapeutic targets in neurological and psychiatric disorders.
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Affiliation(s)
| | - Christian C Naus
- Department of Cellular and Physiological Science, Life Science Institute, University of British ColumbiaVancouver, BC, Canada
| | - Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent UniversityGhent, Belgium
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de ChileSantiago, Chile.,Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto MilenioValparaíso, Chile
| | - Christian Giaume
- Center of Interdisciplinary Research in Biology, Collège de FranceParis, France
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42
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Abstract
Neuronal survival, electrical signaling and synaptic activity require a well-balanced micro-environment in the central nervous system. This is achieved by the blood-brain barrier (BBB), an endothelial barrier situated in the brain capillaries, that controls near-to-all passage in and out of the brain. The endothelial barrier function is highly dependent on signaling interactions with surrounding glial, neuronal and vascular cells, together forming the neuro-glio-vascular unit. Within this functional unit, connexin (Cx) channels are of utmost importance for intercellular communication between the different cellular compartments. Connexins are best known as the building blocks of gap junction (GJ) channels that enable direct cell-cell transfer of metabolic, biochemical and electric signals. In addition, beyond their role in direct intercellular communication, Cxs also form unapposed, non-junctional hemichannels in the plasma membrane that allow the passage of several paracrine messengers, complementing direct GJ communication. Within the NGVU, Cxs are expressed in vascular endothelial cells, including those that form the BBB, and are eminent in astrocytes, especially at their endfoot processes that wrap around cerebral vessels. However, despite the density of Cx channels at this so-called gliovascular interface, it remains unclear as to how Cx-based signaling between astrocytes and BBB endothelial cells may converge control over BBB permeability in health and disease. In this review we describe available evidence that supports a role for astroglial as well as endothelial Cxs in the regulation of BBB permeability during development as well as in disease states.
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Decrock E, Hoorelbeke D, Ramadan R, Delvaeye T, De Bock M, Wang N, Krysko DV, Baatout S, Bultynck G, Aerts A, Vinken M, Leybaert L. Calcium, oxidative stress and connexin channels, a harmonious orchestra directing the response to radiotherapy treatment? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1099-1120. [DOI: 10.1016/j.bbamcr.2017.02.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/02/2017] [Accepted: 02/04/2017] [Indexed: 02/07/2023]
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Walrave L, Vinken M, Albertini G, De Bundel D, Leybaert L, Smolders IJ. Inhibition of Connexin43 Hemichannels Impairs Spatial Short-Term Memory without Affecting Spatial Working Memory. Front Cell Neurosci 2016; 10:288. [PMID: 28066184 PMCID: PMC5168429 DOI: 10.3389/fncel.2016.00288] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 12/02/2016] [Indexed: 12/15/2022] Open
Abstract
Astrocytes are active players in higher brain function as they can release gliotransmitters, which are essential for synaptic plasticity. Various mechanisms have been proposed for gliotransmission, including vesicular mechanisms as well as non-vesicular ones, for example by passive diffusion via connexin hemichannels (HCs). We here investigated whether interfering with connexin43 (Cx43) HCs influenced hippocampal spatial memory. We made use of the peptide Gap19 that blocks HCs but not gap junction channels and is specific for Cx43. To this end, we microinfused transactivator of transcription linked Gap19 (TAT-Gap19) into the brain ventricle of male NMRI mice and assessed spatial memory in a Y maze. We found that the in vivo blockade of Cx43 HCs did not affect the locomotor activity or spatial working memory in a spontaneous alternation Y maze task. Cx43 blockade did however significantly impair the spatial short-term memory in a delayed spontaneous alternation Y maze task. These results indicate that Cx43 HCs play a role in spatial short-term memory.
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Affiliation(s)
- Laura Walrave
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel Brussels, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel Brussels, Belgium
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel Brussels, Belgium
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel Brussels, Belgium
| | - Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Ghent University Ghent, Belgium
| | - Ilse J Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences, Vrije Universiteit Brussel Brussels, Belgium
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45
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Chan DK, Rouse SL. Sound-Induced Intracellular Ca2+ Dynamics in the Adult Hearing Cochlea. PLoS One 2016; 11:e0167850. [PMID: 27959894 PMCID: PMC5154517 DOI: 10.1371/journal.pone.0167850] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/21/2016] [Indexed: 01/21/2023] Open
Abstract
Ca2+ signaling has been implicated in the initial pathophysiologic mechanisms underlying the cochlea's response to acoustic overstimulation. Intracellular Ca2+ signaling (ICS) waves, which occur in glia and retinal cells in response to injury to activate cell regulatory pathways, have been proposed as an early event in cochlear injury. Disruption of ICS activity is thought to underlie Connexin 26-associated hearing loss, the most common genetic form of deafness, and downstream sequelae of ICS wave activity, such as MAP kinase pathway activation, have been implicated in noise-induced hearing loss. However, ICS waves have only been observed in neonatal cochlear cultures and are thought to be quiescent after the onset of hearing. In this study, we employ an acute explant model of an adult, hearing cochlea that retains many in vivo physiologic features to investigate Ca2+ changes in response to sound. We find that both slow monotonic changes in intracellular Ca2+ concentration as well as discrete ICS waves occur with acoustic overstimulation. The ICS waves share many intrinsic features with their better-described neonatal counterparts, including ATP and gap-junction dependence, and propagation velocity and distance. This identification of ICS wave activity in the adult, hearing cochlea thus confirms and characterizes an important early detection mechanism for cochlear trauma and provides a target for interventions for noise-induced and Connexin 26-associated hearing loss.
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Affiliation(s)
- Dylan K. Chan
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, United States of America
- * E-mail:
| | - Stephanie L. Rouse
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, United States of America
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McConnell HL, Kersch CN, Woltjer RL, Neuwelt EA. The Translational Significance of the Neurovascular Unit. J Biol Chem 2016; 292:762-770. [PMID: 27920202 DOI: 10.1074/jbc.r116.760215] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The mammalian brain is supplied with blood by specialized vasculature that is structurally and functionally distinct from that of the periphery. A defining feature of this vasculature is a physical blood-brain barrier (BBB). The BBB separates blood components from the brain microenvironment, regulating the entry and exit of ions, nutrients, macromolecules, and energy metabolites. Over the last two decades, physiological studies of cerebral blood flow dynamics have demonstrated that substantial intercellular communication occurs between cells of the vasculature and the neurons and glia that abut the vasculature. These findings suggest that the BBB does not function independently, but as a module within the greater context of a multicellular neurovascular unit (NVU) that includes neurons, astrocytes, pericytes, and microglia as well as the blood vessels themselves. Here, we describe the roles of these NVU components as well as how they act in concert to modify cerebrovascular function and permeability in health and in select diseases.
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Affiliation(s)
- Heather L McConnell
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
| | - Cymon N Kersch
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
| | - Randall L Woltjer
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
| | - Edward A Neuwelt
- From the Departments of Neurology, Pathology, Neurosurgery, and Veterans Affairs, Oregon Health & Science University, Portland, Oregon 97239-2941
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Gajardo-Gómez R, Labra VC, Maturana CJ, Shoji KF, Santibañez CA, Sáez JC, Giaume C, Orellana JA. Cannabinoids prevent the amyloid β-induced activation of astroglial hemichannels: A neuroprotective mechanism. Glia 2016; 65:122-137. [PMID: 27757991 DOI: 10.1002/glia.23080] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/13/2016] [Accepted: 09/19/2016] [Indexed: 11/06/2022]
Abstract
The mechanisms involved in Alzheimer's disease are not completely understood and how astrocytes and their gliotransmission contribute to this neurodegenerative disease remains to be fully elucidated. Previous studies have shown that amyloid-β peptide (Aβ) induces neuronal death by a mechanism that involves the excitotoxic release of ATP and glutamate associated to astroglial hemichannel opening. We have demonstrated that synthetic and endogenous cannabinoids (CBs) reduce the opening of astrocyte Cx43 hemichannels evoked by activated microglia or inflammatory mediators. Nevertheless, whether CBs could prevent the astroglial hemichannel-dependent death of neurons evoked by Aβ is unknown. Astrocytes as well as acute hippocampal slices were treated with the active fragment of Aβ alone or in combination with the following CBs: WIN, 2-AG, or methanandamide (Meth). Hemichannel activity was monitored by single channel recordings and by time-lapse ethidium uptake while neuronal death was assessed by Fluoro-Jade C staining. We report that CBs fully prevented the hemichannel activity and inflammatory profile evoked by Aβ in astrocytes. Moreover, CBs fully abolished the Aβ-induced release of excitotoxic glutamate and ATP associated to astrocyte Cx43 hemichannel activity, as well as neuronal damage in hippocampal slices exposed to Aβ. Consequently, this work opens novel avenues for alternative treatments that target astrocytes to maintain neuronal function and survival during AD. GLIA 2016 GLIA 2017;65:122-137.
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Affiliation(s)
- Rosario Gajardo-Gómez
- Departamento de Neurología; Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valeria C Labra
- Departamento de Neurología; Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carola J Maturana
- Departamento de Neurología; Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Kenji F Shoji
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile and Instituto Milenio, Centro Interdisciplinario de Neurociencias de Valparaíso, Chile
| | - Cristian A Santibañez
- Departamento de Neurología; Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile and Instituto Milenio, Centro Interdisciplinario de Neurociencias de Valparaíso, Chile
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology, Collège de France/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241, Institut National de la Santé et de la Recherche Médicale U1050, Paris Cedex 05, France
| | - Juan A Orellana
- Departamento de Neurología; Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Coccini T, Caloni F, Ramírez Cando LJ, De Simone U. Cytotoxicity and proliferative capacity impairment induced on human brain cell cultures after short- and long-term exposure to magnetite nanoparticles. J Appl Toxicol 2016; 37:361-373. [DOI: 10.1002/jat.3367] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/21/2016] [Accepted: 06/23/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Teresa Coccini
- Laboratory of Experimental and Clinical Toxicology, Poison Control Centre and National Toxicology Information Centre, Toxicology Division, IRCCS Maugeri Foundation; Scientific Institute of Pavia; Pavia Italy
| | - Francesca Caloni
- Department of Veterinary Medicine (DIMEVET); Università degli Studi di Milano; Milano Italy
| | - Lenin Javier Ramírez Cando
- Centro de Investigación y Valoración de la Biodiversidad (CIVABI); Universidad Politécnica Salesiana; Quito Ecuador
| | - Uliana De Simone
- Laboratory of Experimental and Clinical Toxicology, Poison Control Centre and National Toxicology Information Centre, Toxicology Division, IRCCS Maugeri Foundation; Scientific Institute of Pavia; Pavia Italy
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49
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Connexin43 in retinal injury and disease. Prog Retin Eye Res 2016; 51:41-68. [DOI: 10.1016/j.preteyeres.2015.09.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/25/2015] [Accepted: 09/27/2015] [Indexed: 12/26/2022]
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50
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Sajja VSSS, Hlavac N, VandeVord PJ. Role of Glia in Memory Deficits Following Traumatic Brain Injury: Biomarkers of Glia Dysfunction. Front Integr Neurosci 2016; 10:7. [PMID: 26973475 PMCID: PMC4770450 DOI: 10.3389/fnint.2016.00007] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 02/05/2016] [Indexed: 12/15/2022] Open
Abstract
Historically, glial cells have been recognized as a structural component of the brain. However, it has become clear that glial cells are intimately involved in the complexities of neural networks and memory formations. Astrocytes, microglia, and oligodendrocytes have dynamic responsibilities which substantially impact neuronal function and activities. Moreover, the importance of glia following brain injury has come to the forefront in discussions to improve axonal regeneration and functional recovery. The numerous activities of glia following injury can either promote recovery or underlie the pathobiology of memory deficits. This review outlines the pathological states of glial cells which evolve from their positive supporting roles to those which disrupt synaptic function and neuroplasticity following injury. Evidence suggests that glial cells interact extensively with neurons both chemically and physically, reinforcing their role as pivotal for higher brain functions such as learning and memory. Collectively, this mini review surveys investigations of how glial dysfunction following brain injury can alter mechanisms of synaptic plasticity and how this may be related to an increased risk for persistent memory deficits. We also include recent findings, that demonstrate new molecular avenues for clinical biomarker discovery.
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Affiliation(s)
- Venkata S S S Sajja
- Cellular Imaging Section and Vascular Biology Program, Department of Radiology and Radiological Science, Institute for Cell Engineering, Johns Hopkins University School of Medicine Baltimore, MA, USA
| | - Nora Hlavac
- Department of Biomedical Engineering and Mechanics, Virginia Tech University Blacksburg, VA, USA
| | - Pamela J VandeVord
- Department of Biomedical Engineering and Mechanics, Virginia Tech University Blacksburg, VA, USA
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