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Allende LG, Natalí L, Cragnolini AB, Bollo M, Musri MM, de Mendoza D, Martín MG. Lysosomal cholesterol accumulation in aged astrocytes impairs cholesterol delivery to neurons and can be rescued by cannabinoids. Glia 2024; 72:1746-1765. [PMID: 38856177 DOI: 10.1002/glia.24580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 05/25/2024] [Accepted: 06/02/2024] [Indexed: 06/11/2024]
Abstract
Cholesterol is crucial for the proper functioning of eukaryotic cells, especially neurons, which rely on cholesterol to maintain their complex structure and facilitate synaptic transmission. However, brain cells are isolated from peripheral cholesterol by the blood-brain barrier and mature neurons primarily uptake the cholesterol synthesized by astrocytes for proper function. This study aimed to investigate the effect of aging on cholesterol trafficking in astrocytes and its delivery to neurons. We found that aged astrocytes accumulated high levels of cholesterol in the lysosomal compartment, and this cholesterol buildup can be attributed to the simultaneous occurrence of two events: decreased levels of the ABCA1 transporter, which impairs ApoE-cholesterol export from astrocytes, and reduced expression of NPC1, which hinders cholesterol release from lysosomes. We show that these two events are accompanied by increased microR-33 in aged astrocytes, which targets ABCA1 and NPC1. In addition, we demonstrate that the microR-33 increase is triggered by oxidative stress, one of the hallmarks of aging. By coculture experiments, we show that cholesterol accumulation in astrocytes impairs the cholesterol delivery from astrocytes to neurons. Remarkably, we found that this altered transport of cholesterol could be alleviated through treatment with endocannabinoids as well as cannabidiol or CBD. Finally, according to data demonstrating that aged astrocytes develop an A1 phenotype, we found that cholesterol buildup is also observed in reactive C3+ astrocytes. Given that reduced neuronal cholesterol affects synaptic plasticity, the ability of cannabinoids to restore cholesterol transport from aged astrocytes to neurons holds significant implications in aging and inflammation.
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Affiliation(s)
- Leandro G Allende
- Departamento de Neurobiología Molecular y celular, Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Lautaro Natalí
- Departamento de Bioquímica y Biofísica, Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea B Cragnolini
- Instituto de Investigaciones Biológicas y Tecnológicas, CONICET-UNC, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mariana Bollo
- Departamento de Bioquímica y Biofísica, Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Melina M Musri
- Departamento de Bioquímica y Biofísica, Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Diego de Mendoza
- Laboratorio de Fisiología Microbiana, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Mauricio G Martín
- Departamento de Neurobiología Molecular y celular, Instituto Ferreyra, INIMEC-CONICET-UNC, Universidad Nacional de Córdoba, Córdoba, Argentina
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2
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Leite MC, Galland F, Guerra MC, Rodrigues L, Taday J, Monteforte PT, Hirata H, Gottfried C, Donato R, Smaili S, Gonçalves CA. Astroglial S100B Secretion Is Mediated by Ca 2+ Mobilization from Endoplasmic Reticulum: A Study Using Forskolin and DMSO as Secretagogues. Int J Mol Sci 2023; 24:16576. [PMID: 38068900 PMCID: PMC10706453 DOI: 10.3390/ijms242316576] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/01/2023] [Accepted: 11/09/2023] [Indexed: 12/18/2023] Open
Abstract
S100B, a homodimeric Ca2+-binding protein, is produced and secreted by astrocytes, and its extracellular levels have been used as a glial marker in brain damage and neurodegenerative and psychiatric diseases; however, its mechanism of secretion is elusive. We used primary astrocyte cultures and calcium measurements from real-time fluorescence microscopy to investigate the role of intracellular calcium in S100B secretion. In addition, the dimethyl sulfoxide (DMSO) effect on S100B was investigated in vitro and in vivo using Wistar rats. We found that DMSO, a widely used vehicle in biological assays, is a powerful S100B secretagogue, which caused a biphasic response of Ca2+ mobilization. Our data show that astroglial S100B secretion is triggered by the increase in intracellular Ca2+ and indicate that this increase is due to Ca2+ mobilization from the endoplasmic reticulum. Also, blocking plasma membrane Ca2+ channels involved in the Ca2+ replenishment of internal stores decreased S100B secretion. The DMSO-induced S100B secretion was confirmed in vivo and in ex vivo hippocampal slices. Our data support a nonclassic vesicular export of S100B modulated by Ca2+, and the results might contribute to understanding the mechanism underlying the astroglial release of S100B.
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Affiliation(s)
- Marina C. Leite
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, 2600-Anexo, Porto Alegre 90035-003, RS, Brazil; (M.C.G.); (L.R.); (J.T.); (C.G.); (C.-A.G.)
| | - Fabiana Galland
- Centro de Ciências e Qualidade dos Alimentos, Instituto de Tecnologia de Alimentos, Campinas 13070-178, SP, Brazil;
| | - Maria Cristina Guerra
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, 2600-Anexo, Porto Alegre 90035-003, RS, Brazil; (M.C.G.); (L.R.); (J.T.); (C.G.); (C.-A.G.)
| | - Letícia Rodrigues
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, 2600-Anexo, Porto Alegre 90035-003, RS, Brazil; (M.C.G.); (L.R.); (J.T.); (C.G.); (C.-A.G.)
| | - Jéssica Taday
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, 2600-Anexo, Porto Alegre 90035-003, RS, Brazil; (M.C.G.); (L.R.); (J.T.); (C.G.); (C.-A.G.)
| | - Priscila T. Monteforte
- Departamento de Ciências Naturais, Universidade Federal de São João Del-Rei, São João Del Rei 36301-160, MG, Brazil;
| | - Hanko Hirata
- Departamento de Farmacologia, Universidade Federal de São Paulo, São Paulo 04044-020, SP, Brazil; (H.H.); (S.S.)
| | - Carmem Gottfried
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, 2600-Anexo, Porto Alegre 90035-003, RS, Brazil; (M.C.G.); (L.R.); (J.T.); (C.G.); (C.-A.G.)
| | - Rosario Donato
- Interuniversity Institute of Myology, 06132 Perugia, Italy;
| | - Soraya Smaili
- Departamento de Farmacologia, Universidade Federal de São Paulo, São Paulo 04044-020, SP, Brazil; (H.H.); (S.S.)
| | - Carlos-Alberto Gonçalves
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, 2600-Anexo, Porto Alegre 90035-003, RS, Brazil; (M.C.G.); (L.R.); (J.T.); (C.G.); (C.-A.G.)
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Raj N, Greune L, Kahms M, Mildner K, Franzkoch R, Psathaki OE, Zobel T, Zeuschner D, Klingauf J, Gerke V. Early Endosomes Act as Local Exocytosis Hubs to Repair Endothelial Membrane Damage. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300244. [PMID: 36938863 PMCID: PMC10161044 DOI: 10.1002/advs.202300244] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/21/2023] [Indexed: 05/06/2023]
Abstract
The plasma membrane of a cell is subject to stresses causing ruptures that must be repaired immediately to preserve membrane integrity and ensure cell survival. Yet, the spatio-temporal membrane dynamics at the wound site and the source of the membrane required for wound repair are poorly understood. Here, it is shown that early endosomes, previously only known to function in the uptake of extracellular material and its endocytic transport, are involved in plasma membrane repair in human endothelial cells. Using live-cell imaging and correlative light and electron microscopy, it is demonstrated that membrane injury triggers a previously unknown exocytosis of early endosomes that is induced by Ca2+ entering through the wound. This exocytosis is restricted to the vicinity of the wound site and mediated by the endosomal soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) VAMP2, which is crucial for efficient membrane repair. Thus, the newly identified Ca2+ -evoked and localized exocytosis of early endosomes supplies the membrane material required for rapid resealing of a damaged plasma membrane, thereby providing the first line of defense against damage in mechanically challenged endothelial cells.
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Affiliation(s)
- Nikita Raj
- Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation (ZMBE), Cells in Motion Interfaculty Center, University of Münster, 48149, Münster, Germany
| | - Lilo Greune
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149, Münster, Germany
| | - Martin Kahms
- Institute of Medical Physics and Biophysics, University of Münster, 48149, Münster, Germany
| | - Karina Mildner
- Electron Microscopy Facility, Max Planck Institute for Molecular Biomedicine, 48149, Münster, Germany
| | - Rico Franzkoch
- Department of Biology, integrated Bioimaging Facility (iBiOs), Center of Cellular Nanoanalytics (CellNanO), University of Osnabrück, 49076, Osnabrück, Germany
| | - Olympia Ekaterini Psathaki
- Department of Biology, integrated Bioimaging Facility (iBiOs), Center of Cellular Nanoanalytics (CellNanO), University of Osnabrück, 49076, Osnabrück, Germany
| | - Thomas Zobel
- Imaging Network, Cells in Motion Interfaculty Centre, University of Münster, 48149, Münster, Germany
| | - Dagmar Zeuschner
- Electron Microscopy Facility, Max Planck Institute for Molecular Biomedicine, 48149, Münster, Germany
| | - Jürgen Klingauf
- Institute of Medical Physics and Biophysics, University of Münster, 48149, Münster, Germany
| | - Volker Gerke
- Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation (ZMBE), Cells in Motion Interfaculty Center, University of Münster, 48149, Münster, Germany
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Riederer E, Cang C, Ren D. Lysosomal Ion Channels: What Are They Good For and Are They Druggable Targets? Annu Rev Pharmacol Toxicol 2023; 63:19-41. [PMID: 36151054 DOI: 10.1146/annurev-pharmtox-051921-013755] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Lysosomes play fundamental roles in material digestion, cellular clearance, recycling, exocytosis, wound repair, Ca2+ signaling, nutrient signaling, and gene expression regulation. The organelle also serves as a hub for important signaling networks involving the mTOR and AKT kinases. Electrophysiological recording and molecular and structural studies in the past decade have uncovered several unique lysosomal ion channels and transporters, including TPCs, TMEM175, TRPMLs, CLN7, and CLC-7. They underlie the organelle's permeability to major ions, including K+, Na+, H+, Ca2+, and Cl-. The channels are regulated by numerous cellular factors, ranging from H+ in the lumen and voltage across the lysosomal membrane to ATP in the cytosol to growth factors outside the cell. Genetic variations in the channel/transporter genes are associated with diseases that include lysosomal storage diseases and neurodegenerative diseases. Recent studies with human genetics and channel activators suggest that lysosomal channels may be attractive targets for the development of therapeutics for the prevention of and intervention in human diseases.
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Affiliation(s)
- Erika Riederer
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA; ,
| | - Chunlei Cang
- CAS Key Laboratory of Innate Immunity and Chronic Disease, Neurodegenerative Disorder Research Center, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China;
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA; ,
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5
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Goenaga J, Araque A, Kofuji P, Herrera Moro Chao D. Calcium signaling in astrocytes and gliotransmitter release. Front Synaptic Neurosci 2023; 15:1138577. [PMID: 36937570 PMCID: PMC10017551 DOI: 10.3389/fnsyn.2023.1138577] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/16/2023] [Indexed: 03/06/2023] Open
Abstract
Glia are as numerous in the brain as neurons and widely known to serve supportive roles such as structural scaffolding, extracellular ionic and neurotransmitter homeostasis, and metabolic support. However, over the past two decades, several lines of evidence indicate that astrocytes, which are a type of glia, play active roles in neural information processing. Astrocytes, although not electrically active, can exhibit a form of excitability by dynamic changes in intracellular calcium levels. They sense synaptic activity and release neuroactive substances, named gliotransmitters, that modulate neuronal activity and synaptic transmission in several brain areas, thus impacting animal behavior. This "dialogue" between astrocytes and neurons is embodied in the concept of the tripartite synapse that includes astrocytes as integral elements of synaptic function. Here, we review the recent work and discuss how astrocytes via calcium-mediated excitability modulate synaptic information processing at various spatial and time scales.
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Satarker S, Bojja SL, Gurram PC, Mudgal J, Arora D, Nampoothiri M. Astrocytic Glutamatergic Transmission and Its Implications in Neurodegenerative Disorders. Cells 2022; 11:cells11071139. [PMID: 35406702 PMCID: PMC8997779 DOI: 10.3390/cells11071139] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/12/2022] [Accepted: 03/13/2022] [Indexed: 12/11/2022] Open
Abstract
Several neurodegenerative disorders involve impaired neurotransmission, and glutamatergic neurotransmission sets a prototypical example. Glutamate is a predominant excitatory neurotransmitter where the astrocytes play a pivotal role in maintaining the extracellular levels through release and uptake mechanisms. Astrocytes modulate calcium-mediated excitability and release several neurotransmitters and neuromodulators, including glutamate, and significantly modulate neurotransmission. Accumulating evidence supports the concept of excitotoxicity caused by astrocytic glutamatergic release in pathological conditions. Thus, the current review highlights different vesicular and non-vesicular mechanisms of astrocytic glutamate release and their implication in neurodegenerative diseases. As in presynaptic neurons, the vesicular release of astrocytic glutamate is also primarily meditated by calcium-mediated exocytosis. V-ATPase is crucial in the acidification and maintenance of the gradient that facilitates the vesicular storage of glutamate. Along with these, several other components, such as cystine/glutamate antiporter, hemichannels, BEST-1, TREK-1, purinergic receptors and so forth, also contribute to glutamate release under physiological and pathological conditions. Events of hampered glutamate uptake could promote inflamed astrocytes to trigger repetitive release of glutamate. This could be favorable towards the development and worsening of neurodegenerative diseases. Therefore, across neurodegenerative diseases, we review the relations between defective glutamatergic signaling and astrocytic vesicular and non-vesicular events in glutamate homeostasis. The optimum regulation of astrocytic glutamatergic transmission could pave the way for the management of these diseases and add to their therapeutic value.
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Affiliation(s)
- Sairaj Satarker
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Sree Lalitha Bojja
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Prasada Chowdari Gurram
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Jayesh Mudgal
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Devinder Arora
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia;
| | - Madhavan Nampoothiri
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
- Correspondence:
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7
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Zhang W, Du B, Gao M, Tung CH. A Hybrid Nanogel to Preserve Lysosome Integrity for Fluorescence Imaging. ACS NANO 2021; 15:16442-16451. [PMID: 34612039 DOI: 10.1021/acsnano.1c05864] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Fluorescence imaging of lysosomes provides a powerful tool to probe the lysosome physiology in living cells, yet the continuous light exposure inevitably causes lysosome damage and phototoxicity, which remains a formidable challenge. Here the long-term lysosome tracking with minimized photodamage was realized using a multifunctional nanoprobe, a platinum nanoparticle, and a quinacrine co-loaded nanogel. To construct the hybrid nanogel, cisplatin first functioned as cross-linker to withhold all components and then was reduced to a platinum nanoparticle in situ by ethanol. The platinum nanoparticle enabled a long-term quinacrine fluorescence imaging of lysosome by scavenging the light induced reactive oxygen species which could damage lysosomal membranes.
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Affiliation(s)
- Weiqi Zhang
- State Key Laboratory of Medical Molecular Biology & Department of Biomedical Engineering, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, People's Republic of China
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, New York 10065, United States
| | - Baoji Du
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, New York 10065, United States
| | - Menghan Gao
- State Key Laboratory of Medical Molecular Biology & Department of Biomedical Engineering, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, People's Republic of China
| | - Ching-Hsuan Tung
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, New York 10065, United States
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8
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Astrocyte Gliotransmission in the Regulation of Systemic Metabolism. Metabolites 2021; 11:metabo11110732. [PMID: 34822390 PMCID: PMC8623475 DOI: 10.3390/metabo11110732] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/28/2022] Open
Abstract
Normal brain function highly relies on the appropriate functioning of astrocytes. These glial cells are strategically situated between blood vessels and neurons, provide significant substrate support to neuronal demand, and are sensitive to neuronal activity and energy-related molecules. Astrocytes respond to many metabolic conditions and regulate a wide array of physiological processes, including cerebral vascular remodeling, glucose sensing, feeding, and circadian rhythms for the control of systemic metabolism and behavior-related responses. This regulation ultimately elicits counterregulatory mechanisms in order to couple whole-body energy availability with brain function. Therefore, understanding the role of astrocyte crosstalk with neighboring cells via the release of molecules, e.g., gliotransmitters, into the parenchyma in response to metabolic and neuronal cues is of fundamental relevance to elucidate the distinct roles of these glial cells in the neuroendocrine control of metabolism. Here, we review the mechanisms underlying astrocyte-released gliotransmitters that have been reported to be crucial for maintaining homeostatic regulation of systemic metabolism.
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9
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Actin Cytoskeletal Dynamics in Single-Cell Wound Repair. Int J Mol Sci 2021; 22:ijms221910886. [PMID: 34639226 PMCID: PMC8509258 DOI: 10.3390/ijms221910886] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/04/2021] [Accepted: 10/04/2021] [Indexed: 11/17/2022] Open
Abstract
The plasma membrane protects the eukaryotic cell from its surroundings and is essential for cell viability; thus, it is crucial that membrane disruptions are repaired quickly to prevent immediate dyshomeostasis and cell death. Accordingly, cells have developed efficient repair mechanisms to rapidly reseal ruptures and reestablish membrane integrity. The cortical actin cytoskeleton plays an instrumental role in both plasma membrane resealing and restructuring in response to damage. Actin directly aids membrane repair or indirectly assists auxiliary repair mechanisms. Studies investigating single-cell wound repair have often focused on the recruitment and activation of specialized repair machinery, despite the undeniable need for rapid and dynamic cortical actin modulation; thus, the role of the cortical actin cytoskeleton during wound repair has received limited attention. This review aims to provide a comprehensive overview of membrane repair mechanisms directly or indirectly involving cortical actin cytoskeletal remodeling.
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10
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Mielnicka A, Michaluk P. Exocytosis in Astrocytes. Biomolecules 2021; 11:1367. [PMID: 34572580 PMCID: PMC8471187 DOI: 10.3390/biom11091367] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/17/2022] Open
Abstract
Until recently, astrocytes were thought to be a part of a simple "brain glue" providing only a supporting role for neurons. However, the discoveries of the last two decades have proven astrocytes to be dynamic partners participating in brain metabolism and actively influencing communication between neurons. The means of astrocyte-neuron communication are diverse, although regulated exocytosis has received the most attention but also caused the most debate. Similar to most of eukaryotic cells, astrocytes have a complex range of vesicular organelles which can undergo exocytosis as well as intricate molecular mechanisms that regulate this process. In this review, we focus on the components needed for regulated exocytosis to occur and summarise the knowledge about experimental evidence showing its presence in astrocytes.
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Affiliation(s)
| | - Piotr Michaluk
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute of Experimental Biology, PAS, 02-093 Warsaw, Poland;
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11
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Ung K, Huang TW, Lozzi B, Woo J, Hanson E, Pekarek B, Tepe B, Sardar D, Cheng YT, Liu G, Deneen B, Arenkiel BR. Olfactory bulb astrocytes mediate sensory circuit processing through Sox9 in the mouse brain. Nat Commun 2021; 12:5230. [PMID: 34471129 PMCID: PMC8410770 DOI: 10.1038/s41467-021-25444-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 08/11/2021] [Indexed: 01/07/2023] Open
Abstract
The role of transcription factors during astrocyte development and their subsequent effects on neuronal development has been well studied. Less is known about astrocytes contributions towards circuits and behavior in the adult brain. Astrocytes play important roles in synaptic development and modulation, however their contributions towards neuronal sensory function and maintenance of neuronal circuit architecture remain unclear. Here, we show that loss of the transcription factor Sox9 results in both anatomical and functional changes in adult mouse olfactory bulb (OB) astrocytes, affecting sensory processing. Indeed, astrocyte-specific deletion of Sox9 in the OB results in decreased odor detection thresholds and discrimination and it is associated with aberrant neuronal sensory response maps. At functional level, loss of astrocytic Sox9 impairs the electrophysiological properties of mitral and tufted neurons. RNA-sequencing analysis reveals widespread changes in the gene expression profiles of OB astrocytes. In particular, we observe reduced GLT-1 expression and consequential alterations in glutamate transport. Our findings reveal that astrocytes are required for physiological sensory processing and we identify astrocytic Sox9 as an essential transcriptional regulator of mature astrocyte function in the mouse OB.
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Affiliation(s)
- Kevin Ung
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
| | - Teng-Wei Huang
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, USA
| | - Brittney Lozzi
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, USA
| | - Junsung Woo
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, USA
| | - Elizabeth Hanson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Brandon Pekarek
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Burak Tepe
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
| | - Debosmita Sardar
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, USA
| | - Yi-Ting Cheng
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, USA
| | - Gary Liu
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Benjamin Deneen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA.
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, USA.
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA.
| | - Benjamin R Arenkiel
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA.
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12
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Pham C, Hérault K, Oheim M, Maldera S, Vialou V, Cauli B, Li D. Astrocytes respond to a neurotoxic Aβ fragment with state-dependent Ca 2+ alteration and multiphasic transmitter release. Acta Neuropathol Commun 2021; 9:44. [PMID: 33726852 PMCID: PMC7968286 DOI: 10.1186/s40478-021-01146-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/28/2021] [Indexed: 12/13/2022] Open
Abstract
Excessive amounts of amyloid β (Aβ) peptide have been suggested to dysregulate synaptic transmission in Alzheimer's disease (AD). As a major type of glial cell in the mammalian brain, astrocytes regulate neuronal function and undergo activity alterations upon Aβ exposure. Yet the mechanistic steps underlying astrocytic responses to Aβ peptide remain to be elucidated. Here by fluorescence imaging of signaling pathways, we dissected astrocytic responses to Aβ25-35 peptide, a neurotoxic Aβ fragment present in AD patients. In native health astrocytes, Aβ25-35 evoked Ca2+ elevations via purinergic receptors, being also dependent on the opening of connexin (CX) hemichannels. Aβ25-35, however, induced a Ca2+ diminution in Aβ-preconditioned astrocytes as a result of the potentiation of the plasma membrane Ca2+ ATPase (PMCA). The PMCA and CX protein expression was observed with immunostaining in the brain tissue of hAPPJ20 AD mouse model. We also observed both Ca2+-independent and Ca2+-dependent glutamate release upon astrocytic Aβ exposure, with the former mediated by CX hemichannel and the latter by both anion channels and lysosome exocytosis. Our results suggest that Aβ peptide causes state-dependent responses in astrocytes, in association with a multiphasic release of signaling molecules. This study therefore helps to understand astrocyte engagement in AD-related amyloidopathy.
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13
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Lysosomal Functions in Glia Associated with Neurodegeneration. Biomolecules 2021; 11:biom11030400. [PMID: 33803137 PMCID: PMC7999372 DOI: 10.3390/biom11030400] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 12/12/2022] Open
Abstract
Lysosomes are cellular organelles that contain various acidic digestive enzymes. Despite their small size, they have multiple functions. Lysosomes remove or recycle unnecessary cell parts. They repair damaged cellular membranes by exocytosis. Lysosomes also sense cellular energy status and transmit signals to the nucleus. Glial cells are non-neuronal cells in the nervous system and have an active role in homeostatic support for neurons. In response to dynamic cues, glia use lysosomal pathways for the secretion and uptake of regulatory molecules, which affect the physiology of neighboring neurons. Therefore, functional aberration of glial lysosomes can trigger neuronal degeneration. Here, we review lysosomal functions in oligodendrocytes, astrocytes, and microglia, with emphasis on neurodegeneration.
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14
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Plasma membrane integrity in health and disease: significance and therapeutic potential. Cell Discov 2021; 7:4. [PMID: 33462191 PMCID: PMC7813858 DOI: 10.1038/s41421-020-00233-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/23/2020] [Indexed: 12/13/2022] Open
Abstract
Maintenance of plasma membrane integrity is essential for normal cell viability and function. Thus, robust membrane repair mechanisms have evolved to counteract the eminent threat of a torn plasma membrane. Different repair mechanisms and the bio-physical parameters required for efficient repair are now emerging from different research groups. However, less is known about when these mechanisms come into play. This review focuses on the existence of membrane disruptions and repair mechanisms in both physiological and pathological conditions, and across multiple cell types, albeit to different degrees. Fundamentally, irrespective of the source of membrane disruption, aberrant calcium influx is the common stimulus that activates the membrane repair response. Inadequate repair responses can tip the balance between physiology and pathology, highlighting the significance of plasma membrane integrity. For example, an over-activated repair response can promote cancer invasion, while the inability to efficiently repair membrane can drive neurodegeneration and muscular dystrophies. The interdisciplinary view explored here emphasises the widespread potential of targeting plasma membrane repair mechanisms for therapeutic purposes.
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15
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Božić M, Verkhratsky A, Zorec R, Stenovec M. Exocytosis of large-diameter lysosomes mediates interferon γ-induced relocation of MHC class II molecules toward the surface of astrocytes. Cell Mol Life Sci 2020; 77:3245-3264. [PMID: 31667557 PMCID: PMC7391398 DOI: 10.1007/s00018-019-03350-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/01/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022]
Abstract
Astrocytes are the key homeostatic cells in the central nervous system; initiation of reactive astrogliosis contributes to neuroinflammation. Pro-inflammatory cytokine interferon γ (IFNγ) induces the expression of the major histocompatibility complex class II (MHCII) molecules, involved in antigen presentation in reactive astrocytes. The pathway for MHCII delivery to the astrocyte plasma membrane, where MHCII present antigens, is unknown. Rat astrocytes in culture and in organotypic slices were exposed to IFNγ to induce reactive astrogliosis. Astrocytes were probed with optophysiologic tools to investigate subcellular localization of immunolabeled MHCII, and with electrophysiology to characterize interactions of single vesicles with the plasmalemma. In culture and in organotypic slices, IFNγ augmented the astrocytic expression of MHCII, which prominently co-localized with lysosomal marker LAMP1-EGFP, modestly co-localized with Rab7, and did not co-localize with endosomal markers Rab4A, EEA1, and TPC1. MHCII lysosomal localization was corroborated by treatment with the lysosomolytic agent glycyl-L-phenylalanine-β-naphthylamide, which reduced the number of MHCII-positive vesicles. The surface presence of MHCII was revealed by immunolabeling of live non-permeabilized cells. In IFNγ-treated astrocytes, an increased fraction of large-diameter exocytotic vesicles (lysosome-like vesicles) with prolonged fusion pore dwell time and larger pore conductance was recorded, whereas the rate of endocytosis was decreased. Stimulation with ATP, which triggers cytosolic calcium signaling, increased the frequency of exocytotic events, whereas the frequency of full endocytosis was further reduced. In IFNγ-treated astrocytes, MHCII-linked antigen surface presentation is mediated by increased lysosomal exocytosis, whereas surface retention of antigens is prolonged by concomitant inhibition of endocytosis.
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Affiliation(s)
- Mićo Božić
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia
| | - Alexei Verkhratsky
- Celica Biomedical, Tehnološki park 24, 1000, Ljubljana, Slovenia
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
- Achucarro Center for Neuroscience, IKERBASQUE, 48011, Bilbao, Spain
| | - Robert Zorec
- Celica Biomedical, Tehnološki park 24, 1000, Ljubljana, Slovenia.
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia.
| | - Matjaž Stenovec
- Celica Biomedical, Tehnološki park 24, 1000, Ljubljana, Slovenia.
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia.
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16
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Takata-Tsuji F, Chounlamountri N, Do LD, Philippot C, Novion Ducassou J, Couté Y, Ben Achour S, Honnorat J, Place C, Pascual O. Microglia modulate gliotransmission through the regulation of VAMP2 proteins in astrocytes. Glia 2020; 69:61-72. [PMID: 32633839 DOI: 10.1002/glia.23884] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/31/2022]
Abstract
Vesicular release is one of the release mechanisms of various signaling molecules. In neurons, the molecular machinery involved in vesicular release has been designed through evolution to trigger fast and synchronous release of neurotransmitters. Similar machinery with a slower kinetic and a slightly different molecular assembly allows astrocytes to release various transmitters such as adenosine triphosphate (ATP), glutamate, and D-serine. Astrocytes are important modulators of neurotransmission through gliotransmitter release. We recently demonstrated that microglia, another type of glia, release ATP to modulate synaptic transmission using astrocytes as intermediate. We now report that microglia regulate astrocytic gliotransmission through the regulation of SNARE proteins in astrocytes. Indeed, we found that gliotransmission triggered by P2Y1 agonist is impaired in slices from transgenic mice devoid of microglia. Using total internal reflection fluorescence imaging, we found that the vesicular release of gliotransmitter by astrocytes was different in cultures lacking microglia compared to vesicular release in astrocytes cocultured with microglia. Quantification of the kinetic of vesicular release indicates that the overall release appears to be faster in pure astrocyte cultures with more vesicles close to the membrane when compared to astrocytes cocultured with microglia. Finally, biochemical investigation of SNARE protein expression indicates an upregulation of VAMP2 in absence of microglia. Altogether, these results indicate that microglia seems to be involved in the regulation of an astrocytic phenotype compatible with proper gliotransmission. The mechanisms described in this study could be of importance for central nervous system diseases where microglia are activated.
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Affiliation(s)
- Fuyuko Takata-Tsuji
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France.,Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Naura Chounlamountri
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
| | - Le-Duy Do
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
| | - Camille Philippot
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
| | | | - Yohann Couté
- Université Grenoble Alpes, CEA, INSERM, IRIG, BGE, Grenoble, France
| | - Sarrah Ben Achour
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Université PSL, CNRS, INSERM, Paris, France
| | - Jérôme Honnorat
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France.,Centre maladies rares sur les syndromes neurologiques paranéoplasiques, hospices Civils de Lyon, Lyon, France
| | - Christophe Place
- ENS de Lyon, CNRS, Laboratoire de Physique, Université de Lyon, Lyon, France
| | - Olivier Pascual
- INSERM U1217, CNRS UMR5310, Institut NeuroMyoGène, Lyon, France.,Université Claude Bernard Lyon 1 Lyon, Université de Lyon, Lyon, France
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17
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Geng X, Sun Y, Guo Y, Zhao Y, Zhang K, Xiao L, Qu L, Li Z. Fluorescent Carbon Dots for in Situ Monitoring of Lysosomal ATP Levels. Anal Chem 2020; 92:7940-7946. [PMID: 32406677 DOI: 10.1021/acs.analchem.0c01335] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Monitoring the ATP levels in lysosomes in situ is crucial for understanding their involvement in various biological processes but remains difficult due to the interference of ATP in other organelles or the cytoplasm. Here, we report a lysosome-specific fluorescent carbon dot (CD), which can be used to detect ATP in acidic lysosomes with "off-on" changes of yellow fluorescence. These CDs were successfully applied in real-time monitoring of the fluctuating concentration of lysosomal ATP induced by drug stimulation (e.g., chloroquine, etoposide, and oligomycin). Because of the excellent specificity, these CDs are promising agents for drug screening and medical diagnostics through lysosomal ATP monitoring.
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Affiliation(s)
- Xin Geng
- College of Chemistry, Green Catalysis Center, Henan Joint International Research Laboratory of Green Construction of Functional Molecules and Their Bioanalytical Applications, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Yuanqiang Sun
- College of Chemistry, Green Catalysis Center, Henan Joint International Research Laboratory of Green Construction of Functional Molecules and Their Bioanalytical Applications, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Yifei Guo
- College of Chemistry, Green Catalysis Center, Henan Joint International Research Laboratory of Green Construction of Functional Molecules and Their Bioanalytical Applications, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Yanmin Zhao
- College of Chemistry, Green Catalysis Center, Henan Joint International Research Laboratory of Green Construction of Functional Molecules and Their Bioanalytical Applications, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Ke Zhang
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Lehui Xiao
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin 300071, P.R. China
| | - Lingbo Qu
- College of Chemistry, Green Catalysis Center, Henan Joint International Research Laboratory of Green Construction of Functional Molecules and Their Bioanalytical Applications, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Zhaohui Li
- College of Chemistry, Green Catalysis Center, Henan Joint International Research Laboratory of Green Construction of Functional Molecules and Their Bioanalytical Applications, Zhengzhou University, Zhengzhou 450001, P.R. China
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18
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Bai B, Wang XF, Zhang M, Na L, Zhang X, Zhang H, Yang Z, Wang X. The N-glycosylation of Equine Tetherin Affects Antiviral Activity by Regulating Its Subcellular Localization. Viruses 2020; 12:v12020220. [PMID: 32079099 PMCID: PMC7077275 DOI: 10.3390/v12020220] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/28/2020] [Accepted: 02/12/2020] [Indexed: 01/08/2023] Open
Abstract
Tetherin is an interferon-inducible type II transmembrane glycoprotein which inhibits the release of viruses, including retroviruses, through a “physical tethering” model. However, the role that the glycosylation of tetherin plays in its antiviral activity remains controversial. In this study, we found that mutation of N-glycosylation sites resulted in an attenuation of the antiviral activity of equine tetherin (eqTHN), as well as a reduction in the expression of eqTHN at the plasma membrane (PM). In addition, eqTHN N-glycosylation mutants colocalize obviously with ER, CD63, LAMP1 and endosomes, while WT eqTHN do not. Furthermore, we also found that N-glycosylation impacts the transport of eqTHN in the cell not by affecting the endocytosis, but rather by influencing the anterograde trafficking of the protein. These results suggest that the N-glycosylation of eqTHN is important for the antiviral activity of the protein through regulating its normal subcellular localization. This finding will enhance our understanding of the function of this important restriction factor.
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Affiliation(s)
- Bowen Bai
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, Harbin 150069, China; (B.B.); (X.-F.W.); (M.Z.); (L.N.); (X.Z.); (H.Z.)
| | - Xue-Feng Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, Harbin 150069, China; (B.B.); (X.-F.W.); (M.Z.); (L.N.); (X.Z.); (H.Z.)
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Mengmeng Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, Harbin 150069, China; (B.B.); (X.-F.W.); (M.Z.); (L.N.); (X.Z.); (H.Z.)
| | - Lei Na
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, Harbin 150069, China; (B.B.); (X.-F.W.); (M.Z.); (L.N.); (X.Z.); (H.Z.)
| | - Xiangmin Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, Harbin 150069, China; (B.B.); (X.-F.W.); (M.Z.); (L.N.); (X.Z.); (H.Z.)
| | - Haili Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, Harbin 150069, China; (B.B.); (X.-F.W.); (M.Z.); (L.N.); (X.Z.); (H.Z.)
| | - Zhibiao Yang
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Xiaojun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, Harbin 150069, China; (B.B.); (X.-F.W.); (M.Z.); (L.N.); (X.Z.); (H.Z.)
- Correspondence: ; Tel.: +86-451-5105-1749
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19
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Illes P, Burnstock G, Tang Y. Astroglia-Derived ATP Modulates CNS Neuronal Circuits. Trends Neurosci 2019; 42:885-898. [PMID: 31704181 DOI: 10.1016/j.tins.2019.09.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/10/2019] [Accepted: 09/23/2019] [Indexed: 02/08/2023]
Abstract
It is broadly recognized that ATP not only supports energy storage within cells but is also a transmitter/signaling molecule that serves intercellular communication. Whereas the fast (co)transmitter function of ATP in the peripheral nervous system has been convincingly documented, in the central nervous system (CNS) ATP appears to be primarily a slow transmitter/modulator. Data discussed in the present review suggest that the slow modulatory effects of ATP arise as a result of its vesicular/nonvesicular release from astrocytes. ATP acts together with other glial signaling molecules such as cytokines, chemokines, and free radicals to modulate neuronal circuits. Hence, astrocytes are positioned at the crossroads of the neuron-glia-neuron communication pathway.
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Affiliation(s)
- Peter Illes
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany; Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine (TCM), 610075 Chengdu, China.
| | - Geoffrey Burnstock
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Yong Tang
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine (TCM), 610075 Chengdu, China
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20
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Vardjan N, Parpura V, Verkhratsky A, Zorec R. Gliocrine System: Astroglia as Secretory Cells of the CNS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:93-115. [PMID: 31583585 DOI: 10.1007/978-981-13-9913-8_4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Astrocytes are secretory cells, actively participating in cell-to-cell communication in the central nervous system (CNS). They sense signaling molecules in the extracellular space, around the nearby synapses and also those released at much farther locations in the CNS, by their cell surface receptors, get excited to then release their own signaling molecules. This contributes to the brain information processing, based on diffusion within the extracellular space around the synapses and on convection when locales relatively far away from the release sites are involved. These functions resemble secretion from endocrine cells, therefore astrocytes were termed to be a part of the gliocrine system in 2015. An important mechanism, by which astrocytes release signaling molecules is the merger of the vesicle membrane with the plasmalemma, i.e., exocytosis. Signaling molecules stored in astroglial secretory vesicles can be discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This leads to a fusion pore formation, a channel that must widen to allow the exit of the Vesiclal cargo. Upon complete vesicle membrane fusion, this process also integrates other proteins, such as receptors, transporters and channels into the plasma membrane, determining astroglial surface signaling landscape. Vesiclal cargo, together with the whole vesicle can also exit astrocytes by the fusion of multivesicular bodies with the plasma membrane (exosomes) or by budding of vesicles (ectosomes) from the plasma membrane into the extracellular space. These astroglia-derived extracellular vesicles can later interact with various target cells. Here, the characteristics of four types of astroglial secretory vesicles: synaptic-like microvesicles, dense-core vesicles, secretory lysosomes, and extracellular vesicles, are discussed. Then machinery for vesicle-based exocytosis, second messenger regulation and the kinetics of exocytotic vesicle content discharge or release of extracellular vesicles are considered. In comparison to rapidly responsive, electrically excitable neurons, the receptor-mediated cytosolic excitability-mediated astroglial exocytotic vesicle-based transmitter release is a relatively slow process.
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Affiliation(s)
- Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK.,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, 1000, Ljubljana, Slovenia. .,Celica Biomedical, 1000, Ljubljana, Slovenia.
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21
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High-resolution detection of ATP release from single cultured mouse dorsal horn spinal cord glial cells and its modulation by noradrenaline. Purinergic Signal 2019; 15:403-420. [PMID: 31444738 DOI: 10.1007/s11302-019-09673-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/12/2019] [Indexed: 12/30/2022] Open
Abstract
Human embryonic kidney 293 (HEK293) cells stably transfected with the rat P2X2 receptor subunit were preincubated with 200 nM progesterone (HEK293-P2X2-PROG), a potent positive allosteric modulator of homomeric P2X2 receptors, and used to detect low nanomolar concentrations of extracellular ATP. Fura-2-loaded HEK293-P2X2-PROG cells were acutely plated on top of cultured DH glial cells to quantify ATP release from single DH glial cells. Application of the α1 adrenoceptor agonist phenylephrine (PHE, 20 μM) or of a low K+ (0.2 mM) solution evoked reversible increases in the intracellular calcium concentration ([Ca2+]i) in the biosensor cells. A reversible increase in [Ca2+]i was also detected in half of the biosensor cells following the interruption of general extracellular perfusion. All increases in [Ca2+]i were blocked in the presence of the P2X2 antagonist PPADS or after preloading the glial cells with the calcium chelator BAPTA, indicating that they were due to calcium-dependent ATP release from the glial cells. ATP release induced by PHE was blocked by -L-phenylalanine 2-naphtylamide (GPN) that permeabilizes secretory lysosomes and bafilomycin A1 (Baf A1), an inhibitor of the H+-pump of acidic secretory vesicles. By contrast, ATP release induced by application of a low-K+ solution was abolished by Baf A1 but not by GPN. Finally, spontaneous ATP release observed after interrupting general perfusion was insensitive to both GPN and Baf A1 pretreatment. Our results indicate that ATP is released in a calcium-dependent manner from two distinct vesicular pools and one non-vesicular pool coexisting in DH glial cells and that noradrenaline and PHE selectively target the secretory lysosome pool.
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22
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Datta G, Miller NM, Afghah Z, Geiger JD, Chen X. HIV-1 gp120 Promotes Lysosomal Exocytosis in Human Schwann Cells. Front Cell Neurosci 2019; 13:329. [PMID: 31379513 PMCID: PMC6650616 DOI: 10.3389/fncel.2019.00329] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/03/2019] [Indexed: 12/31/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) associated neuropathy is the most common neurological complication of HIV-1, with debilitating pain affecting the quality of life. HIV-1 gp120 plays an important role in the pathogenesis of HIV neuropathy via direct neurotoxic effects or indirect pro-inflammatory responses. Studies have shown that gp120-induced release of mediators from Schwann cells induce CCR5-dependent DRG neurotoxicity, however, CCR5 antagonists failed to improve pain in HIV- infected individuals. Thus, there is an urgent need for a better understanding of neuropathic pain pathogenesis and developing effective therapeutic strategies. Because lysosomal exocytosis in Schwann cells is an indispensable process for regulating myelination and demyelination, we determined the extent to which gp120 affected lysosomal exocytosis in human Schwann cells. We demonstrated that gp120 promoted the movement of lysosomes toward plasma membranes, induced lysosomal exocytosis, and increased the release of ATP into the extracellular media. Mechanistically, we demonstrated lysosome de-acidification, and activation of P2X4 and VNUT to underlie gp120-induced lysosome exocytosis. Functionally, we demonstrated that gp120-induced lysosome exocytosis and release of ATP from Schwann cells leads to increases in intracellular calcium and generation of cytosolic reactive oxygen species in DRG neurons. Our results suggest that gp120-induced lysosome exocytosis and release of ATP from Schwann cells and DRG neurons contribute to the pathogenesis of HIV-1 associated neuropathy.
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Affiliation(s)
- Gaurav Datta
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Nicole M Miller
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Zahra Afghah
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
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23
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Andrews NW. Solving the secretory acid sphingomyelinase puzzle: Insights from lysosome-mediated parasite invasion and plasma membrane repair. Cell Microbiol 2019; 21:e13065. [PMID: 31155842 DOI: 10.1111/cmi.13065] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/03/2019] [Accepted: 05/30/2019] [Indexed: 12/19/2022]
Abstract
Acid sphingomyelinase (ASM) is a lysosomal enzyme that cleaves the phosphorylcholine head group of sphingomyelin, generating ceramide. Recessive mutations in SMPD1, the gene encoding ASM, cause Niemann-Pick Disease Types A and B. These disorders are attributed not only to lipid accumulation inside lysosomes but also to changes on the outer leaflet of the plasma membrane, highlighting an extracellular role for ASM. Secretion of ASM occurs under physiological conditions, and earlier studies proposed two forms of the enzyme, one resident in lysosomes and another form that would be diverted to the secretory pathway. Such differential intracellular trafficking has been difficult to explain because there is only one SMPD1 transcript that generates an active enzyme, found primarily inside lysosomes. Unexpectedly, studies of cell invasion by the protozoan parasite Trypanosoma cruzi revealed that conventional lysosomes can fuse with the plasma membrane in response to elevations in intracellular Ca2+ , releasing their contents extracellularly. ASM exocytosed from lysosomes remodels the outer leaflet of the plasma membrane, promoting parasite invasion and wound repair. Here, we discuss the possibility that ASM release during lysosomal exocytosis, in response to various forms of stress, may represent a major source of the secretory form of this enzyme.
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Affiliation(s)
- Norma W Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland
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24
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Colucci-Guyon E, Batista AS, Oliveira SDS, Blaud M, Bellettini IC, Marteyn BS, Leblanc K, Herbomel P, Duval R. Ultraspecific live imaging of the dynamics of zebrafish neutrophil granules by a histopermeable fluorogenic benzochalcone probe. Chem Sci 2019; 10:3654-3670. [PMID: 30996961 PMCID: PMC6432617 DOI: 10.1039/c8sc05593a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 02/12/2019] [Indexed: 12/13/2022] Open
Abstract
Neutrophil granules (NGs) are key components of the innate immune response and mark the development of neutrophilic granulocytes in mammals. However, there has been no specific fluorescent vital stain up to now to monitor their dynamics within a whole live organism. We rationally designed a benzochalcone fluorescent probe (HAB) featuring high tissue permeability and optimal photophysics such as elevated quantum yield, pronounced solvatochromism and target-induced fluorogenesis. Phenotypic screening identified HAB as the first cell- and organelle-specific small-molecule fluorescent tracer of NGs in live zebrafish larvae, with no labeling of other cell types or organelles. HAB staining was independent of the state of neutrophil activation, labeling NGs of both resting and phagocytically active neutrophils with equal specificity. By high-resolution live imaging, we documented the dynamics of HAB-stained NGs during phagocytosis. Upon zymosan injection, labeled NGs were rapidly recruited to the forming phagosomes. Despite being a reversible ligand, HAB could not be displaced by high concentrations of pharmacologically relevant competing chalcones, indicating that this specific labeling was the result of the HAB's precise physicochemical signature rather than a general feature of chalcones. However, one of the competitors was discovered as a promising interstitial fluorescent tracer illuminating zebrafish histology, similarly to BODIPY-ceramide. As a yellow-emitting histopermeable vital stain, HAB functionally and spectrally complements most genetically incorporated fluorescent tags commonly used in live zebrafish biology, holding promise for the study of neutrophil-dependent responses relevant to human physiopathology such as developmental defects, inflammation and infection. Furthermore, HAB intensely labeled isolated live human neutrophils at the level of granulated subcellular structures consistent with human NGs, suggesting that the labeling of NGs by HAB is not restricted to the zebrafish model but also relevant to mammalian systems.
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Affiliation(s)
- Emma Colucci-Guyon
- Institut Pasteur , Unité Macrophages et Développement de l'Immunité , Paris , 75015 , France .
- CNRS , UMR 3738 , Paris , France
| | - Ariane S Batista
- Nanotechnology Engineering Program , Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia - COPPE , Universidade Federal do Rio de Janeiro , Rio de Janeiro , 21941-972 , Brazil
| | | | - Magali Blaud
- LCRB , CNRS , Université Paris 5 , Sorbonne Paris Cité , Paris , 75006 , France
| | - Ismael C Bellettini
- Departamento de Ciências Exatas e Educaçao , Universidade Federal de Santa Catarina , Blumenau , 89036-256 , Brazil
| | - Benoit S Marteyn
- Institut Pasteur , Unité de Pathogénie Microbienne Moléculaire , Paris , 75015 , France
- INSERM , UMR 786 , Paris , France
| | - Karine Leblanc
- BioCIS , CNRS , Université Paris-Sud 11 , Châtenay-Malabry , 92290 , France
| | - Philippe Herbomel
- Institut Pasteur , Unité Macrophages et Développement de l'Immunité , Paris , 75015 , France .
- CNRS , UMR 3738 , Paris , France
| | - Romain Duval
- MERIT , IRD , Université Paris 5 , Sorbonne Paris Cité , Paris , 75006 , France .
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25
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Li Z, Gu Y, Wen R, Shen F, Tian HL, Yang GY, Zhang Z. Lysosome exocytosis is involved in astrocyte ATP release after oxidative stress induced by H 2O 2. Neurosci Lett 2019; 705:251-258. [PMID: 30928480 DOI: 10.1016/j.neulet.2019.03.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 03/20/2019] [Accepted: 03/26/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE Studies demonstrated that oxidative damage decreased intracellular ATP level in astrocytes. However, the pathway mediated ATP level decrease is obscure. Our previous study found intracellular ATP could be released via lysosome exocytosis in astrocytes. Here, we explored whether lysosome exocytosis was involved in ATP release during oxidative stress induced by H2O2 in astrocytes. METHODS Astrocytes were isolated from the cortex of neonatal rats. Intracellular lysosomes and calcium signals were stained in astrocytes before and after H2O2 stimulation. ATP molecules location and ATP level were detected by immunostaining and bioluminescence method, respectively. Extracellular β-Hexosaminidase and LDH were examined by colorimetric method. RESULTS We found that ATP located in lysosome of astrocytes. H2O2 stimulation resulted in the decrease of lysosomes staining and the increase of extracellular ATP, compared to the control (p < 0.05). At the same time, intracellular Fluo4 signals and β-Hexosaminidase level were also increased (p < 0.05). Extracellular LDH level did not show an increase, suggesting that there is no cell membrane damage after H2O2 stimulation. Glycyl-phenylalanine 2-naphthylamide blocked lysosome exocytosis and inhibited ATP release in astrocytes after H2O2-treatment (p < 0.05). CONCLUSION Our results indicated that H2O2 induced ATP release from intracellular to extracellular via lysosome exocytosis. The increase of intracellular Ca2+ was necessary for lysosome release under oxidative stress induced by H2O2.
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Affiliation(s)
- Zongwei Li
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Medicine, Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Yong Gu
- Department of Pediatrics, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, 241001, China
| | - Ruoxue Wen
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Medicine, Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Fanxia Shen
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Heng-Li Tian
- Department of Neurosurgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
| | - Guo-Yuan Yang
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Medicine, Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China; Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200025, China.
| | - Zhijun Zhang
- Shanghai JiaoTong Affiliated Sixth People's Hospital, School of Medicine, Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China.
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26
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Fingolimod Suppresses the Proinflammatory Status of Interferon-γ-Activated Cultured Rat Astrocytes. Mol Neurobiol 2019; 56:5971-5986. [PMID: 30701416 DOI: 10.1007/s12035-019-1481-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/10/2019] [Indexed: 12/14/2022]
Abstract
Astroglia, the primary homeostatic cells of the central nervous system, play an important role in neuroinflammation. They act as facultative immunocompetent antigen-presenting cells (APCs), expressing major histocompatibility complex (MHC) class II antigens upon activation with interferon (IFN)-γ and possibly other proinflammatory cytokines that are upregulated in disease states, including multiple sclerosis (MS). We characterized the anti-inflammatory effects of fingolimod (FTY720), an established drug for MS, and its phosphorylated metabolite (FTY720-P) in IFN-γ-activated cultured rat astrocytes. The expression of MHC class II compartments, β2 adrenergic receptor (ADR-β2), and nuclear factor kappa-light-chain enhancer of activated B cells subunit p65 (NF-κB p65) was quantified in immunofluorescence images acquired by laser scanning confocal microscopy. In addition, MHC class II-enriched endocytotic vesicles were labeled by fluorescent dextran and their mobility analyzed in astrocytes subjected to different treatments. FTY720 and FTY720-P treatment significantly reduced the number of IFN-γ-induced MHC class II compartments and substantially increased ADR-β2 expression, which is otherwise small or absent in astrocytes in MS. These effects could be partially attributed to the observed decrease in NF-κB p65 expression, because the NF-κB signaling cascade is activated in inflammatory processes. We also found attenuated trafficking and secretion from dextran-labeled endo-/lysosomes that may hinder efficient delivery of MHC class II molecules to the plasma membrane. Our data suggest that FTY720 and FTY720-P at submicromolar concentrations mediate anti-inflammatory effects on astrocytes by suppressing their action as APCs, which may further downregulate the inflammatory process in the brain, constituting the therapeutic effect of fingolimod in MS.
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Ye Y, Hui L, Lakpa KL, Xing Y, Wollenzien H, Chen X, Zhao JX, Geiger JD. Effects of silica nanoparticles on endolysosome function in primary cultured neurons 1. Can J Physiol Pharmacol 2018; 97:297-305. [PMID: 30312546 DOI: 10.1139/cjpp-2018-0401] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Silica nanoparticles (SiNPs) have been used as vehicles for drug delivery, molecular detection, and cellular manipulations in nanoneuromedicine. SiNPs may cause adverse effects in the brain including neurotoxicity, neuroinflammation, neurodegeneration, and enhancing levels of amyloid beta (Aβ) protein-all pathological hallmarks of Alzheimer's disease. Therefore, the extent to which SiNPs influence Aβ generation and the underlying mechanisms by which this occurs deserve investigation. Our studies were focused on the effects of SiNPs on endolysosomes which uptake, traffic, and mediate the actions of SiNPs. These organelles are also where amyloidogenesis largely originates. We found that SiNPs, in primary cultured hippocampal neurons, accumulated in endolysosomes and caused a rapid and persistent deacidification of endolysosomes. SiNPs significantly reduced endolysosome calcium stores as indicated by a significant reduction in the ability of the lysosomotropic agent glycyl-l-phenylalanine 2-naphthylamide (GPN) to release calcium from endolysosomes. SiNPs increased Aβ1-40 secretion, whereas 2 agents that acidified endolysosomes, ML-SA1 and CGS21680, blocked SiNP-induced deacidification and increased generation of Aβ1-40. Our findings suggest that SiNP-induced deacidification of and calcium release from endolysosomes might be mechanistically linked to increased amyloidogenesis. The use of SiNPs might not be the best nanomaterial for therapeutic strategies against Alzheimer's disease and other neurological disorders linked to endolysosome dysfunction.
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Affiliation(s)
- Yan Ye
- a Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Liang Hui
- a Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Koffi L Lakpa
- a Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Yuqian Xing
- b Department of Chemistry, University of North Dakota, Grand Forks, ND 58202, USA
| | - Hannah Wollenzien
- a Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Xuesong Chen
- a Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Julia Xiaojun Zhao
- b Department of Chemistry, University of North Dakota, Grand Forks, ND 58202, USA
| | - Jonathan D Geiger
- a Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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28
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Wang G, Nola S, Bovio S, Bun P, Coppey-Moisan M, Lafont F, Galli T. Biomechanical Control of Lysosomal Secretion Via the VAMP7 Hub: A Tug-of-War between VARP and LRRK1. iScience 2018; 4:127-143. [PMID: 30240735 PMCID: PMC6147023 DOI: 10.1016/j.isci.2018.05.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 02/05/2018] [Accepted: 05/23/2018] [Indexed: 12/21/2022] Open
Abstract
The rigidity of the cell environment can vary tremendously between tissues and in pathological conditions. How this property may affect intracellular membrane dynamics is still largely unknown. Here, using atomic force microscopy, we show that cells deficient in the secretory lysosome v-SNARE VAMP7 are impaired in adaptation to substrate rigidity. Conversely, VAMP7-mediated secretion is stimulated by more rigid substrate and this regulation depends on the Longin domain of VAMP7. We further find that the Longin domain binds the kinase and retrograde trafficking adaptor LRRK1 and that LRRK1 negatively regulates VAMP7-mediated exocytosis. Conversely, VARP, a VAMP7- and kinesin 1-interacting protein, further controls the availability for secretion of peripheral VAMP7 vesicles and response of cells to mechanical constraints. LRRK1 and VARP interact with VAMP7 in a competitive manner. We propose a mechanism whereby biomechanical constraints regulate VAMP7-dependent lysosomal secretion via LRRK1 and VARP tug-of-war control of the peripheral pool of secretory lysosomes.
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Affiliation(s)
- Guan Wang
- Membrane Traffic in Health & Disease, Institut Jacques Monod, CNRS UMR7592, INSERM U950, Sorbonne Paris-Cité, Université Paris Diderot, Paris 75205, France; Membrane Traffic in Healthy & Diseased Brain, Center of Psychiatry and Neurosciences, INSERM U894, Sorbonne Paris-Cité, Université Paris Descartes, 102-108 rue de la Santé, Paris 75014, France
| | - Sébastien Nola
- Membrane Traffic in Health & Disease, Institut Jacques Monod, CNRS UMR7592, INSERM U950, Sorbonne Paris-Cité, Université Paris Diderot, Paris 75205, France; Membrane Traffic in Healthy & Diseased Brain, Center of Psychiatry and Neurosciences, INSERM U894, Sorbonne Paris-Cité, Université Paris Descartes, 102-108 rue de la Santé, Paris 75014, France
| | - Simone Bovio
- Cellular Microbiology and Physics of Infection Group, Center for Infection and Immunity of Lille, CNRS UMR 8204, INSERM U1019, Institut Pasteur de Lille, Centre Hospitalier Régional de Lille, Université de Lille, Lille, France
| | - Philippe Bun
- NeurImag Tech Core Facility, Center of Psychiatry and Neurosciences, INSERM U894, Sorbonne Paris-Cité, Université Paris Descartes, Paris 75014, France
| | - Maïté Coppey-Moisan
- Mechanotransduction: from Cell Surface to Nucleus, Institut Jacques Monod, CNRS UMR7592, Sorbonne Paris-Cité, Université Paris-Diderot, Paris, France
| | - Frank Lafont
- Cellular Microbiology and Physics of Infection Group, Center for Infection and Immunity of Lille, CNRS UMR 8204, INSERM U1019, Institut Pasteur de Lille, Centre Hospitalier Régional de Lille, Université de Lille, Lille, France
| | - Thierry Galli
- Membrane Traffic in Health & Disease, Institut Jacques Monod, CNRS UMR7592, INSERM U950, Sorbonne Paris-Cité, Université Paris Diderot, Paris 75205, France; Membrane Traffic in Healthy & Diseased Brain, Center of Psychiatry and Neurosciences, INSERM U894, Sorbonne Paris-Cité, Université Paris Descartes, 102-108 rue de la Santé, Paris 75014, France.
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Sipos A, Kim KJ, Chow RH, Flodby P, Borok Z, Crandall ED. Alveolar epithelial cell processing of nanoparticles activates autophagy and lysosomal exocytosis. Am J Physiol Lung Cell Mol Physiol 2018; 315:L286-L300. [PMID: 29722567 DOI: 10.1152/ajplung.00108.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Using confocal microscopy, we quantitatively assessed uptake, processing, and egress of near-infrared (NIR)-labeled carboxylated polystyrene nanoparticles (PNP) in live alveolar epithelial cells (AEC) during interactions with primary rat AEC monolayers (RAECM). PNP fluorescence intensity (content) and colocalization with intracellular vesicles in a cell were determined over the entire cell volume via z stacking. Isotropic cuvette-based microfluorimetry was used to determine PNP concentration ([PNP]) from anisotropic measurements of PNP content assessed by confocal microscopy. Results showed that PNP uptake kinetics and steady-state intracellular content decreased as diameter increased from 20 to 200 nm. For 20-nm PNP, uptake rate and steady-state intracellular content increased with increased apical [PNP] but were unaffected by inhibition of endocytic pathways. Intracellular PNP increasingly colocalized with autophagosomes and/or lysosomes over time. PNP egress exhibited fast Ca2+ concentration-dependent release and a slower diffusion-like process. Inhibition of microtubule polymerization curtailed rapid PNP egress, resulting in elevated vesicular and intracellular PNP content. Interference with autophagosome formation led to slower PNP uptake and markedly decreased steady-state intracellular content. At steady state, cytosolic [PNP] was higher than apical [PNP], and vesicular [PNP] (~80% of intracellular PNP content) exceeded both cytosolic and intracellular [PNP]. These data are consistent with the following hypotheses: 1) autophagic processing of nanoparticles is essential for maintenance of AEC integrity; 2) altered autophagy and/or lysosomal exocytosis may lead to AEC injury; and 3) intracellular [PNP] in AEC can be regulated, suggesting strategies for enhancement of nanoparticle-driven AEC gene/drug delivery and/or amelioration of AEC nanoparticle-related cellular toxicity.
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Affiliation(s)
- Arnold Sipos
- Hastings Center for Pulmonary Research, Keck School of Medicine, University of Southern California , Los Angeles, California.,Will Rogers Institute Pulmonary Research Center, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Medicine, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Kwang-Jin Kim
- Hastings Center for Pulmonary Research, Keck School of Medicine, University of Southern California , Los Angeles, California.,Will Rogers Institute Pulmonary Research Center, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Medicine, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California , Los Angeles, California.,Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California , Los Angeles, California
| | - Robert H Chow
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California , Los Angeles, California.,Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Per Flodby
- Hastings Center for Pulmonary Research, Keck School of Medicine, University of Southern California , Los Angeles, California.,Will Rogers Institute Pulmonary Research Center, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Medicine, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Zea Borok
- Hastings Center for Pulmonary Research, Keck School of Medicine, University of Southern California , Los Angeles, California.,Will Rogers Institute Pulmonary Research Center, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Medicine, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - Edward D Crandall
- Hastings Center for Pulmonary Research, Keck School of Medicine, University of Southern California , Los Angeles, California.,Will Rogers Institute Pulmonary Research Center, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Medicine, Keck School of Medicine, University of Southern California , Los Angeles, California.,Department of Pathology, Keck School of Medicine, University of Southern California , Los Angeles, California.,Mork Family Department of Chemical Engineering and Materials Science, Viterbi School of Engineering, University of Southern California , Los Angeles, California
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30
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Beckel JM, Gómez NM, Lu W, Campagno KE, Nabet B, Albalawi F, Lim JC, Boesze-Battaglia K, Mitchell CH. Stimulation of TLR3 triggers release of lysosomal ATP in astrocytes and epithelial cells that requires TRPML1 channels. Sci Rep 2018; 8:5726. [PMID: 29636491 PMCID: PMC5893592 DOI: 10.1038/s41598-018-23877-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/16/2018] [Indexed: 01/25/2023] Open
Abstract
Cross-reactions between innate immunity, lysosomal function, and purinergic pathways may link signaling systems in cellular pathologies. We found activation of toll-like receptor 3 (TLR3) triggers lysosomal ATP release from both astrocytes and retinal pigmented epithelial (RPE) cells. ATP efflux was accompanied by lysosomal acid phosphatase and beta hexosaminidase release. Poly(I:C) alkalinized lysosomes, and lysosomal alkalization with bafilomycin or chloroquine triggered ATP release. Lysosomal rupture with glycyl-L-phenylalanine-2-naphthylamide (GPN) eliminated both ATP and acid phosphatase release. Secretory lysosome marker LAMP3 colocalized with VNUT, while MANT-ATP colocalized with LysoTracker. Unmodified membrane-impermeant 21-nt and "non-targeting" scrambled 21-nt siRNA triggered ATP and acid phosphatase release, while smaller 16-nt RNA was ineffective. Poly(I:C)-dependent ATP release was reduced by TBK-1 block and in TRPML1-/- cells, while TRPML activation with ML-SA1 was sufficient to release both ATP and acid phosphatase. The ability of poly(I:C) to raise cytoplasmic Ca2+ was abolished by removing extracellular ATP with apyrase, suggesting ATP release by poly(I:C) increased cellular signaling. Starvation but not rapamycin prevented lysosomal ATP release. In summary, stimulation of TLR3 triggers lysosomal alkalization and release of lysosomal ATP through activation of TRPML1; this links innate immunity to purinergic signaling via lysosomal physiology, and suggests even scrambled siRNA can influence these pathways.
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Affiliation(s)
- Jonathan M Beckel
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Néstor Más Gómez
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Wennan Lu
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Keith E Campagno
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Bardia Nabet
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Farraj Albalawi
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Orthodontics, University of Pennsylvania, Philadelphia, PA, USA
| | - Jason C Lim
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Physiology, University of Pennsylvania, Philadelphia, PA, USA.
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31
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Xiong Y, Teng S, Zheng L, Sun S, Li J, Guo N, Li M, Wang L, Zhu F, Wang C, Rao Z, Zhou Z. Stretch-induced Ca 2+ independent ATP release in hippocampal astrocytes. J Physiol 2018; 596:1931-1947. [PMID: 29488635 DOI: 10.1113/jp275805] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 02/21/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Similar to neurons, astrocytes actively participate in synaptic transmission via releasing gliotransmitters. The Ca2+ -dependent release of gliotransmitters includes glutamate and ATP. Following an 'on-cell-like' mechanical stimulus to a single astrocyte, Ca2+ independent single, large, non-quantal, ATP release occurs. Astrocytic ATP release is inhibited by either selective antagonist treatment or genetic knockdown of P2X7 receptor channels. Our work suggests that ATP can be released from astrocytes via two independent pathways in hippocampal astrocytes; in addition to the known Ca2+ -dependent vesicular release, larger non-quantal ATP release depends on P2X7 channels following mechanical stretch. ABSTRACT Astrocytic ATP release is essential for brain functions such as synaptic long-term potentiation for learning and memory. However, whether and how ATP is released via exocytosis remains hotly debated. All previous studies of non-vesicular ATP release have used indirect assays. By contrast, two recent studies report vesicular ATP release using more direct assays. In the present study, using patch clamped 'ATP-sniffer cells', we re-investigated astrocytic ATP release at single-vesicle resolution in hippocampal astrocytes. Following an 'on-cell-like' mechanical stimulus of a single astrocyte, a Ca2+ independent single large non-quantal ATP release occurred, in contrast to the Ca2+ -dependent multiple small quantal ATP release in a chromaffin cell. The mechanical stimulation-induced ATP release from an astrocyte was inhibited by either exposure to a selective antagonist or genetic knockdown of P2X7 receptor channels. Functional P2X7 channels were expressed in astrocytes in hippocampal brain slices. Thus, in addition to small quantal ATP release, larger non-quantal ATP release depends on P2X7 channels in astrocytes.
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Affiliation(s)
- Yingfei Xiong
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China.,Institute of Neurosciences, Fourth Military Medical University, Xi'an, China.,Department of Neurosurgery, Affiliated Hospital of Air Force Institute of Aeromedicine, Beijing, China
| | - Sasa Teng
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Lianghong Zheng
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Suhua Sun
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Jie Li
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Ning Guo
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Mingli Li
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Li Wang
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Feipeng Zhu
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Changhe Wang
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Zhiren Rao
- Institute of Neurosciences, Fourth Military Medical University, Xi'an, China
| | - Zhuan Zhou
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Institute of Molecular Medicine, Peking University, Beijing, China
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32
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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: 952] [Impact Index Per Article: 158.7] [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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Menéndez-Méndez A, Díaz-Hernández JI, Ortega F, Gualix J, Gómez-Villafuertes R, Miras-Portugal MT. Specific Temporal Distribution and Subcellular Localization of a Functional Vesicular Nucleotide Transporter (VNUT) in Cerebellar Granule Neurons. Front Pharmacol 2017; 8:951. [PMID: 29311945 PMCID: PMC5744399 DOI: 10.3389/fphar.2017.00951] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/15/2017] [Indexed: 12/14/2022] Open
Abstract
Adenosine triphosphate (ATP) is an important extracellular neurotransmitter that participates in several critical processes like cell differentiation, neuroprotection or axon guidance. Prior to its exocytosis, ATP must be stored in secretory vesicles, a process that is mediated by the Vesicular Nucleotide Transporter (VNUT). This transporter has been identified as the product of the SLC17A9 gene and it is prominently expressed in discrete brain areas, including the cerebellum. The main population of cerebellar neurons, the glutamatergic granule neurons, depends on purinergic signaling to trigger neuroprotective responses. However, while nucleotide receptors like P2X7 and P2Y13 are known to be involved in neuroprotection, the mechanisms that regulate ATP release in relation to such events are less clearly understood. In this work, we demonstrate that cerebellar granule cells express a functional VNUT that is involved in the regulation of ATP exocytosis. Numerous vesicles loaded with this nucleotide can be detected in these granule cells and are staining by the fluorescent ATP-marker, quinacrine. High potassium stimulation reduces quinacrine fluorescence in granule cells, indicating they release ATP via calcium dependent exocytosis. Specific subcellular markers were used to assess the localization of VNUT in granule cells, and the transporter was detected in both the axonal and somatodendritic compartments, most predominantly in the latter. However, co-localization with the specific lysosomal marker LAMP-1 indicated that VNUT can also be found in non-synaptic vesicles, such as lysosomes. Interestingly, the weak co-localization between VNUT and VGLUT1 suggests that the ATP and glutamate vesicle pools are segregated, as also observed in the cerebellar cortex. During post-natal cerebellar development, VNUT is found in granule cell precursors, co-localizing with markers of immature cells like doublecortin, suggesting that this transporter may be implicated in the initial stages of granule cell development.
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Affiliation(s)
- Aida Menéndez-Méndez
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Juan I Díaz-Hernández
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Felipe Ortega
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Javier Gualix
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Rosa Gómez-Villafuertes
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - María T Miras-Portugal
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
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35
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Cho CH. Commentary: Identification of diverse astrocyte populations and their malignant analogs. Front Mol Neurosci 2017; 10:193. [PMID: 28659761 PMCID: PMC5468430 DOI: 10.3389/fnmol.2017.00193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/30/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Chang-Hoon Cho
- College of Public Health, Korea UniversitySeoul, South Korea
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36
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Zigdon H, Meshcheriakova A, Farfel-Becker T, Volpert G, Sabanay H, Futerman AH. Altered lysosome distribution is an early neuropathological event in neurological forms of Gaucher disease. FEBS Lett 2017; 591:774-783. [PMID: 28186340 DOI: 10.1002/1873-3468.12591] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/01/2017] [Accepted: 02/01/2017] [Indexed: 11/08/2022]
Abstract
In the lysosomal storage disorder Gaucher disease (GD), glucosylceramide (GlcCer) accumulates due to the defective activity of glucocerebrosidase. A subset of GD patients develops neuropathology. We now show mislocalization of Limp2-positive puncta and a large reduction in the number of Lamp1-positive puncta, which are associated with impaired tubulin. These changes occur at an early stage in animal models of GD, prior to development of overt symptoms and considerably earlier than neuronal loss. Altered lysosomal localization and cytoskeleton disruption precede the neuroinflammatory pathways, axonal dystrophy and neuronal loss previously characterized in neuronal forms of GD.
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Affiliation(s)
- Hila Zigdon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Anna Meshcheriakova
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Farfel-Becker
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Giora Volpert
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Helena Sabanay
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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Bohmbach K, Schwarz MK, Schoch S, Henneberger C. The structural and functional evidence for vesicular release from astrocytes in situ. Brain Res Bull 2017; 136:65-75. [PMID: 28122264 DOI: 10.1016/j.brainresbull.2017.01.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/17/2017] [Accepted: 01/19/2017] [Indexed: 12/31/2022]
Abstract
The concept of the tripartite synapse states that bi-directional signalling between perisynaptic astrocyte processes, presynaptic axonal boutons and postsynaptic neuronal structures defines the properties of synaptic information processing. Ca2+-dependent vesicular release from astrocytes, as one of the mechanisms of astrocyte-neuron communication, has attracted particular attention but has also been the subject of intense debate. In neurons, regulated vesicular release is a strongly coordinated process. It requires a complex release machinery comprised of many individual components ranging from vesicular neurotransmitter transporters and soluble NSF attachment protein receptors (SNARE) proteins to Ca2+-sensors and the proteins that spatially and temporally control exocytosis of synaptic vesicles. If astrocytes employ similar mechanisms to release neurotransmitters is less well understood. The aim of this review is therefore to discuss recent experimental evidence that sheds light on the central structural components responsible for vesicular release from astrocytes in situ.
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Affiliation(s)
- Kirsten Bohmbach
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany.
| | - Martin K Schwarz
- Department of Epileptology, University of Bonn Medical School, Bonn, Germany
| | - Susanne Schoch
- Institute of Neuropathology, University of Bonn Medical School, Bonn, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; Institute of Neurology, University College London, London, United Kingdom.
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38
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Zorec R, Parpura V, Verkhratsky A. Astroglial Vesicular Trafficking in Neurodegenerative Diseases. Neurochem Res 2016; 42:905-917. [DOI: 10.1007/s11064-016-2055-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/30/2016] [Accepted: 08/31/2016] [Indexed: 12/20/2022]
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39
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Monif M, Reid CA, Powell KL, Drummond KJ, O'Brien TJ, Williams DA. Interleukin-1β has trophic effects in microglia and its release is mediated by P2X7R pore. J Neuroinflammation 2016; 13:173. [PMID: 27364756 PMCID: PMC4929731 DOI: 10.1186/s12974-016-0621-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 06/10/2016] [Indexed: 11/21/2022] Open
Abstract
Background Enhanced expression of the purinergic P2X7 receptor (P2X7R) occurs in several neuroinflammatory conditions where increased microglial activation is a co-existing feature. P2X7 receptors can function either as a cation channel or, upon continued stimulation, a large pore. P2X7R-over-expression alone is sufficient to drive microglial activation and proliferation in a process that is P2X7R pore dependent, although the biological signaling pathway through which this occurs remains unclear. Once activated, microglia are known to release a number of bioactive substances that include the proinflammatory cytokine interleukin-1β (IL-1β). Previous studies have linked P2X7R stimulation to the processing and release of IL-1β, but whether the channel or pore state of P2X7R is predominant in driving IL-1β release is unknown and is a major aim of this study. In addition, we will determine whether IL-1β has trophic effects on surrounding microglia. Methods Electron microscopy and immunohistochemistry were used to delineate the sub-cellular localization of P2X7R and IL-1β in primary hippocampal rat cultures. FM1-43 fluorescent dye and confocal microscopy were used to quantify vesicular exocytosis from microglia expressing the pore-forming P2X7R versus a non-pore-forming point mutant, P2X7RG345Y. IL-1β in culture was quantified with an enzyme-linked immunosorbent assay (ELISA). IL-1β intracellular processing was blocked with inhibition of caspase 1 (with a synthetic peptide antagonist), and its extracellular form was neutralized with an IL-1β neutralizing antibody. Microglial activation and proliferation was quantified immunohistochemically with confocal microscopy. Results P2X7R and IL-1β were co-localized in lysosomes. Vesicular exocytosis was higher in microglia expressing the pore-forming P2X7R compared to those expressing the non-pore-forming mutant. There was increased IL-1β in cultures expressing the pore-forming P2X7R, and this proinflammatory cytokine was found to mediate the trophic effects of P2X7R pore in microglia. Inhibition of IL-1β production and function resulted in a significant decrease in P2X7R-mediated microglial activation and proliferation. Conclusions IL-1β is a mediator of microglial activation and proliferation, and its release/production is P2X7R pore dependent. Blockade of P2X7R pore could serve as a therapeutic target in alleviating the degree of inflammation seen in neurodegenerative and neoplastic conditions. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0621-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mastura Monif
- Department of Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, 3010, Australia.,The Department of Neurology, The Royal Melbourne Hospital, Parkville, Victoria, 3052, Australia
| | - Christopher A Reid
- Howard Florey Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Kim L Powell
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Katherine J Drummond
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Terrence J O'Brien
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - David A Williams
- Department of Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, 3010, Australia.
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40
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Son SM, Cha MY, Choi H, Kang S, Choi H, Lee MS, Park SA, Mook-Jung I. Insulin-degrading enzyme secretion from astrocytes is mediated by an autophagy-based unconventional secretory pathway in Alzheimer disease. Autophagy 2016; 12:784-800. [PMID: 26963025 DOI: 10.1080/15548627.2016.1159375] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The secretion of proteins that lack a signal sequence to the extracellular milieu is regulated by their transition through the unconventional secretory pathway. IDE (insulin-degrading enzyme) is one of the major proteases of amyloid beta peptide (Aβ), a presumed causative molecule in Alzheimer disease (AD) pathogenesis. IDE acts in the extracellular space despite having no signal sequence, but the underlying mechanism of IDE secretion extracellularly is still unknown. In this study, we found that IDE levels were reduced in the cerebrospinal fluid (CSF) of patients with AD and in pathology-bearing AD-model mice. Since astrocytes are the main cell types for IDE secretion, astrocytes were treated with Aβ. Aβ increased the IDE levels in a time- and concentration-dependent manner. Moreover, IDE secretion was associated with an autophagy-based unconventional secretory pathway, and depended on the activity of RAB8A and GORASP (Golgi reassembly stacking protein). Finally, mice with global haploinsufficiency of an essential autophagy gene, showed decreased IDE levels in the CSF in response to an intracerebroventricular (i.c.v.) injection of Aβ. These results indicate that IDE is secreted from astrocytes through an autophagy-based unconventional secretory pathway in AD conditions, and that the regulation of autophagy is a potential therapeutic target in addressing Aβ pathology.
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Affiliation(s)
- Sung Min Son
- a Department of Biochemistry & Biomedical Sciences , Seoul National University College of Medicine , Seoul , Korea.,b Neuroscience Research Institute, Seoul National University College of Medicine , Seoul , Korea
| | - Moon-Yong Cha
- a Department of Biochemistry & Biomedical Sciences , Seoul National University College of Medicine , Seoul , Korea
| | - Heesun Choi
- a Department of Biochemistry & Biomedical Sciences , Seoul National University College of Medicine , Seoul , Korea
| | - Seokjo Kang
- a Department of Biochemistry & Biomedical Sciences , Seoul National University College of Medicine , Seoul , Korea
| | - Hyunjung Choi
- a Department of Biochemistry & Biomedical Sciences , Seoul National University College of Medicine , Seoul , Korea
| | - Myung-Shik Lee
- c Department of Medicine , Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul , Korea
| | - Sun Ah Park
- d Department of Neurology , Soonchunhyang University Bucheon Hospital , Bucheon , Korea
| | - Inhee Mook-Jung
- a Department of Biochemistry & Biomedical Sciences , Seoul National University College of Medicine , Seoul , Korea.,b Neuroscience Research Institute, Seoul National University College of Medicine , Seoul , Korea
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41
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Verkhratsky A, Matteoli M, Parpura V, Mothet JP, Zorec R. Astrocytes as secretory cells of the central nervous system: idiosyncrasies of vesicular secretion. EMBO J 2016; 35:239-57. [PMID: 26758544 DOI: 10.15252/embj.201592705] [Citation(s) in RCA: 285] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/01/2015] [Indexed: 11/09/2022] Open
Abstract
Astrocytes are housekeepers of the central nervous system (CNS) and are important for CNS development, homeostasis and defence. They communicate with neurones and other glial cells through the release of signalling molecules. Astrocytes secrete a wide array of classic neurotransmitters, neuromodulators and hormones, as well as metabolic, trophic and plastic factors, all of which contribute to the gliocrine system. The release of neuroactive substances from astrocytes occurs through several distinct pathways that include diffusion through plasmalemmal channels, translocation by multiple transporters and regulated exocytosis. As in other eukaryotic cells, exocytotic secretion from astrocytes involves divergent secretory organelles (synaptic-like microvesicles, dense-core vesicles, lysosomes, exosomes and ectosomes), which differ in size, origin, cargo, membrane composition, dynamics and functions. In this review, we summarize the features and functions of secretory organelles in astrocytes. We focus on the biogenesis and trafficking of secretory organelles and on the regulation of the exocytotic secretory system in the context of healthy and diseased astrocytes.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK Achucarro Center for Neuroscience, IKERBASQUE Basque Foundation for Science, Bilbao, Spain Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain University of Nizhny Novgorod, Nizhny Novgorod, Russia Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia Celica BIOMEDICAL, Ljubljana, Slovenia
| | - Michela Matteoli
- CNR Institute of Neuroscience, Milano, Italy Humanitas Research Hospital, Rozzano, Italy
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jean-Pierre Mothet
- Team Gliotransmission & Synaptopathies, Aix-Marseille University CNRS, CRN2M UMR7286, Marseille, France
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia Celica BIOMEDICAL, Ljubljana, Slovenia
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42
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Yakovlev A, Lyzhin A, Aleksandrova O, Khaspekov L, Gulyaeva N. Trophic factors deprivation induces long-term protection of neurons against excitotoxic damage. ACTA ACUST UNITED AC 2016; 62:656-663. [DOI: 10.18097/pbmc20166206656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
One of the strategies to induce tolerance of neurons to toxic injury is preconditioning. Preconditioning is caused by a weak damage of cells, which become more resistant to subsequent, more severe damage. We found that preconditioning by deprivation of trophic factors, or deprivation of trophic factor and glucose effectively protects neurons against subsequent toxic effects of glutamate. Deprivation of trophic factors plays a decisive role in the development of resistance, regardless of whether it has been combined with glucose deprivation or not. Neuronal protection is achieved when the deprivation lasts from 30 min to two hours and is kept for a period of from one to five days. Preconditioning is accompanied neuronal secretion of cathepsin B occurs. We suggest that this phenomenon is associated with a more general process of exocytosis of lysosomes triggered by deprivation of trophic factors.
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Affiliation(s)
- A.A. Yakovlev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia; Moscow Research and Clinical Center for Neuropsychiatry, Moscow, Russia
| | - A.A. Lyzhin
- Brain Research Center at Research Center of Neurology, Moscow, Russia
| | - O.P. Aleksandrova
- Brain Research Center at Research Center of Neurology, Moscow, Russia
| | - L.G. Khaspekov
- Brain Research Center at Research Center of Neurology, Moscow, Russia
| | - N.V. Gulyaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia; Moscow Research and Clinical Center for Neuropsychiatry, Moscow, Russia
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44
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Yakovlev AA, Gulyaeva NV. Possible role of proteases in preconditioning of brain cells to pathological conditions. BIOCHEMISTRY (MOSCOW) 2015; 80:163-71. [PMID: 25756531 DOI: 10.1134/s0006297915020030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Preconditioning (PC) is one of the most effective strategies to reduce the severity of cell damage, in particular of nervous tissue cells. Although PC mechanisms are studied insufficiently, it is clear that proteases are involved in them, but their role has yet been not studied in detail. In this work, some mechanisms of a potential recruiting of proteases in PC are considered. Our attention is mainly focused on the protease families of caspases and cathepsins and on protease receptors. We present evidence that just these proteins are involved in the PC of brain cells. A hypothesis is proposed that secreted cathepsin B is involved in the realization of PC through activation of PAR2 receptor.
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Affiliation(s)
- A A Yakovlev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 117485, Russia.
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Sahlender DA, Savtchouk I, Volterra A. What do we know about gliotransmitter release from astrocytes? Philos Trans R Soc Lond B Biol Sci 2015; 369:20130592. [PMID: 25225086 PMCID: PMC4173278 DOI: 10.1098/rstb.2013.0592] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Astrocytes participate in information processing by actively modulating synaptic properties via gliotransmitter release. Various mechanisms of astrocytic release have been reported, including release from storage organelles via exocytosis and release from the cytosol via plasma membrane ion channels and pumps. It is still not fully clear which mechanisms operate under which conditions, but some of them, being Ca2+-regulated, may be physiologically relevant. The properties of Ca2+-dependent transmitter release via exocytosis or via ion channels are different and expected to produce different extracellular transmitter concentrations over time and to have distinct functional consequences. The molecular aspects of these two release pathways are still under active investigation. Here, we discuss the existing morphological and functional evidence in support of either of them. Transgenic mouse models, specific antagonists and localization studies have provided insight into regulated exocytosis, albeit not in a systematic fashion. Even more remains to be uncovered about the details of channel-mediated release. Better functional tools and improved ultrastructural approaches are needed in order fully to define specific modalities and effects of astrocytic gliotransmitter release pathways.
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Affiliation(s)
- Daniela A Sahlender
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, Lausanne 1005, Switzerland
| | - Iaroslav Savtchouk
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, Lausanne 1005, Switzerland
| | - Andrea Volterra
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, Lausanne 1005, Switzerland
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Ropert N, Jalil A, Li D. Expression and cellular function of vSNARE proteins in brain astrocytes. Neuroscience 2015; 323:76-83. [PMID: 26518463 DOI: 10.1016/j.neuroscience.2015.10.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/07/2015] [Accepted: 10/21/2015] [Indexed: 12/27/2022]
Abstract
Gray matter protoplasmic astrocytes, a major type of glial cell in the mammalian brain, extend thin processes ensheathing neuronal synaptic terminals. Albeit electrically silent, astrocytes respond to neuronal activity with Ca(2+) signals that trigger the release of gliotransmitters, such as glutamate, d-serine, and ATP, which modulate synaptic transmission. It has been suggested that the astrocytic processes, together with neuronal pre- and post-synaptic elements, constitute a tripartite synapse, and that astrocytes actively regulate information processing. Astrocytic vesicles expressing VAMP2 and VAMP3 vesicular SNARE (vSNARE) proteins have been suggested to be a key feature of the tripartite synapse and mediate gliotransmitter release through Ca(2+)-regulated exocytosis. However, the concept of exocytotic release of gliotransmitters by astrocytes has been challenged. Here we review studies investigating the expression profile of VAMP2 and VAMP3 vSNARE proteins in rodent astrocytes, and the functional implication of VAMP2/VAMP3 vesicles in astrocyte signaling. We also discuss our recent data suggesting that astrocytic VAMP3 vesicles regulate the trafficking of glutamate transporters at the plasma membrane and glutamate uptake. A better understanding of the functional consequences of the astrocytic vSNARE vesicles on glutamate signaling, neuronal excitability and plasticity, will require the development of new strategies to selectively interrogate the astrocytic vesicles trafficking in vivo.
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Affiliation(s)
- N Ropert
- Brain Physiology Laboratory, CNRS UMR8118, Paris F-75006, France; Fédération de Recherche en Neurosciences, FR 3636, Université Paris Descartes, 45 rue des Saints Pères, Paris F-75006, France; Sorbonne Paris Cité, 190, avenue de France, Paris F-75013, France
| | - A Jalil
- Brain Physiology Laboratory, CNRS UMR8118, Paris F-75006, France; Fédération de Recherche en Neurosciences, FR 3636, Université Paris Descartes, 45 rue des Saints Pères, Paris F-75006, France; Sorbonne Paris Cité, 190, avenue de France, Paris F-75013, France
| | - D Li
- Brain Physiology Laboratory, CNRS UMR8118, Paris F-75006, France; Fédération de Recherche en Neurosciences, FR 3636, Université Paris Descartes, 45 rue des Saints Pères, Paris F-75006, France; Sorbonne Paris Cité, 190, avenue de France, Paris F-75013, France.
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47
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Sreetama SC, Takano T, Nedergaard M, Simon SM, Jaiswal JK. Injured astrocytes are repaired by Synaptotagmin XI-regulated lysosome exocytosis. Cell Death Differ 2015; 23:596-607. [PMID: 26450452 DOI: 10.1038/cdd.2015.124] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 08/03/2015] [Accepted: 08/17/2015] [Indexed: 12/21/2022] Open
Abstract
Astrocytes are known to facilitate repair following brain injury; however, little is known about how injured astrocytes repair themselves. Repair of cell membrane injury requires Ca(2+)-triggered vesicle exocytosis. In astrocytes, lysosomes are the main Ca(2+)-regulated exocytic vesicles. Here we show that astrocyte cell membrane injury results in a large and rapid calcium increase. This triggers robust lysosome exocytosis where the fusing lysosomes release all luminal contents and merge fully with the plasma membrane. In contrast to this, receptor stimulation produces a small sustained calcium increase, which is associated with partial release of the lysosomal luminal content, and the lysosome membrane does not merge into the plasma membrane. In most cells, lysosomes express the synaptotagmin (Syt) isoform Syt VII; however, this isoform is not present on astrocyte lysosomes and exogenous expression of Syt VII on lysosome inhibits their exocytosis. Deletion of one of the most abundant Syt isoform in astrocyte--Syt XI--suppresses astrocyte lysosome exocytosis. This identifies lysosome as Syt XI-regulated exocytic vesicle in astrocytes. Further, inhibition of lysosome exocytosis (by Syt XI depletion or Syt VII expression) prevents repair of injured astrocytes. These results identify the lysosomes and Syt XI as the sub-cellular and molecular regulators, respectively of astrocyte cell membrane repair.
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Affiliation(s)
- S C Sreetama
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
| | - T Takano
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - M Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - S M Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, USA
| | - J K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA.,Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue NW, Washington, DC, USA
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Hui L, Geiger NH, Bloor-Young D, Churchill GC, Geiger JD, Chen X. Release of calcium from endolysosomes increases calcium influx through N-type calcium channels: Evidence for acidic store-operated calcium entry in neurons. Cell Calcium 2015; 58:617-27. [PMID: 26475051 DOI: 10.1016/j.ceca.2015.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/02/2015] [Accepted: 10/04/2015] [Indexed: 01/22/2023]
Abstract
Neurons possess an elaborate system of endolysosomes. Recently, endolysosomes were found to have readily releasable stores of intracellular calcium; however, relatively little is known about how such 'acidic calcium stores' affect calcium signaling in neurons. Here we demonstrated in primary cultured neurons that calcium released from acidic calcium stores triggered calcium influx across the plasma membrane, a phenomenon we have termed "acidic store-operated calcium entry (aSOCE)". aSOCE was functionally distinct from store-operated calcium release and calcium entry involving endoplasmic reticulum. aSOCE appeared to be governed by N-type calcium channels (NTCCs) because aSOCE was attenuated significantly by selectively blocking NTCCs or by siRNA knockdown of NTCCs. Furthermore, we demonstrated that NTCCs co-immunoprecipitated with the lysosome associated membrane protein 1 (LAMP1), and that aSOCE is accompanied by increased cell-surface expression levels of NTCC and LAMP1 proteins. Moreover, we demonstrated that siRNA knockdown of LAMP1 or Rab27a, both of which are key proteins involved in lysosome exocytosis, attenuated significantly aSOCE. Taken together our data suggest that aSOCE occurs in neurons, that aSOCE plays an important role in regulating the levels and actions of intraneuronal calcium, and that aSOCE is regulated at least in part by exocytotic insertion of N-type calcium channels into plasma membranes through LAMP1-dependent lysosome exocytosis.
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Affiliation(s)
- Liang Hui
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Nicholas H Geiger
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
| | - Duncan Bloor-Young
- Department of Pharmacology, University of Oxford, Mansfield Rd., Oxford OX1 3QT, UK
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Mansfield Rd., Oxford OX1 3QT, UK
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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49
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Vardjan N, Parpura V, Zorec R. Loose excitation-secretion coupling in astrocytes. Glia 2015; 64:655-67. [PMID: 26358496 DOI: 10.1002/glia.22920] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/26/2015] [Indexed: 12/19/2022]
Abstract
Astrocytes play an important housekeeping role in the central nervous system. Additionally, as secretory cells, they actively participate in cell-to-cell communication, which can be mediated by membrane-bound vesicles. The gliosignaling molecules stored in these vesicles are discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This process is termed exocytosis, regulated by SNARE proteins, and triggered by elevations in cytosolic calcium levels, which are necessary and sufficient for exocytosis in astrocytes. For astrocytic exocytosis, calcium is sourced from the intracellular endoplasmic reticulum store, although its entry from the extracellular space contributes to cytosolic calcium dynamics in astrocytes. Here, we discuss calcium management in astrocytic exocytosis and the properties of the membrane-bound vesicles that store gliosignaling molecules, including the vesicle fusion machinery and kinetics of vesicle content discharge. In astrocytes, the delay between the increase in cytosolic calcium activity and the discharge of secretions from the vesicular lumen is orders of magnitude longer than that in neurons. This relatively loose excitation-secretion coupling is likely tailored to the participation of astrocytes in modulating neural network processing.
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Affiliation(s)
- Nina Vardjan
- Celica Biomedical, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy & Nanotechnology Laboratories, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama
| | - Robert Zorec
- Celica Biomedical, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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50
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Abstract
Neuroglia, the "glue" that fills the space between neurons in the central nervous system, takes active part in nerve cell signaling. Neuroglial cells, astroglia, oligodendroglia, and microglia, are together about as numerous as neurons in the brain as a whole, and in the cerebral cortex grey matter, but the proportion varies widely among brain regions. Glial volume, however, is less than one-fifth of the tissue volume in grey matter. When stimulated by neurons or other cells, neuroglial cells release gliotransmitters by exocytosis, similar to neurotransmitter release from nerve endings, or by carrier-mediated transport or channel flux through the plasma membrane. Gliotransmitters include the common neurotransmitters glutamate and GABA, the nonstandard amino acid d-serine, the high-energy phosphate ATP, and l-lactate. The latter molecule is a "buffer" between glycolytic and oxidative metabolism as well as a signaling substance recently shown to act on specific lactate receptors in the brain. Complementing neurotransmission at a synapse, neuroglial transmission often implies diffusion of the transmitter over a longer distance and concurs with the concept of volume transmission. Transmission from glia modulates synaptic neurotransmission based on energetic and other local conditions in a volume of tissue surrounding the individual synapse. Neuroglial transmission appears to contribute significantly to brain functions such as memory, as well as to prevalent neuropathologies.
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Affiliation(s)
- Vidar Gundersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Jon Storm-Mathisen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Linda Hildegard Bergersen
- SN-Lab, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, and CMBN/SERTA/Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway; Department of Neurology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Center for Healthy Aging, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; and Brain and Muscle Energy Group, Department of Oral Biology and Division of Anatomy, Department of Molecular Medicine, University of Oslo, Oslo, Norway
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