1
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Liu W, Gao T, Li N, Shao S, Liu B. Vesicle fusion and release in neurons under dynamic mechanical equilibrium. iScience 2024; 27:109793. [PMID: 38736547 PMCID: PMC11088343 DOI: 10.1016/j.isci.2024.109793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
Vesicular fusion plays a pivotal role in cellular processes, involving stages like vesicle trafficking, fusion pore formation, content release, and membrane integration or separation. This dynamic process is regulated by a complex interplay of protein assemblies, osmotic forces, and membrane tension, which together maintain a mechanical equilibrium within the cell. Changes in cellular mechanics or external pressures prompt adjustments in this equilibrium, highlighting the system's adaptability. This review delves into the synergy between intracellular proteins, structural components, and external forces in facilitating vesicular fusion and release. It also explores how cells respond to mechanical stress, maintaining equilibrium and offering insights into vesicle fusion mechanisms and the development of neurological disorders.
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Affiliation(s)
- Wenhao Liu
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
| | - Tianyu Gao
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
| | - Na Li
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
- Faculty of Medicine, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
| | - Shuai Shao
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
- Faculty of Medicine, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
| | - Bo Liu
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
- Faculty of Medicine, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
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2
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Calì C. Regulated exocytosis from astrocytes: a matter of vesicles? Front Neurosci 2024; 18:1393165. [PMID: 38800570 PMCID: PMC11116621 DOI: 10.3389/fnins.2024.1393165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/30/2024] [Indexed: 05/29/2024] Open
Affiliation(s)
- Corrado Calì
- Department of Neuroscience “Rita Levi Montalcini”, University of Turin, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Italy
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3
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Zorec R, Wu LG. Barriers to exocytotic vesicle discharge. Cell Calcium 2023; 112:102737. [PMID: 37099857 DOI: 10.1016/j.ceca.2023.102737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Regulated exocytosis, a universal process of eukaryotic cells, involves the merging between the vesicle membrane and the plasma membrane, plays a key role in cell-to-cell communication, particularly in the release of hormones and neurotransmitters. There are a number of barriers a vesicle needs to pass to discharge vesicle content to the extracellular space. At the pre-fusion site vesicles need to be transported to the sites on the plasma membrane where the merger may begin. Classically cytoskeleton was considered an important barrier for vesicle translocation and was thought to be disintegrated to allow vesicle access to the plasma membrane [1]. However, it was considered later that cytoskeletal elements may also play a role at the post-fusion stage, promoting the vesicle merger with the plasma membrane and fusion pore expansion [4,22,23]. In this Special Issue of Cell Calcium entitled "Regulated Exocytosis", the authors address outstanding issues related to vesicle chemical messenger release by regulated exocytosis, including that related to the question whether vesicle content discharge is complete or only partial upon the merging of the vesicle membrane with the plasma membrane triggered by Ca2+. Among processes that limit vesicle discharge at the post-fusion stage is the accumulation of cholesterol in some vesicles [19], a process that has recently been associated with cell aging [20].
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Affiliation(s)
- Robert Zorec
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia; Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Medical Faculty, 1000 Ljubljana, Slovenia.
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
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4
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Bayonés L, Guerra-Fernández MJ, Hinostroza F, Báez-Matus X, Vásquez-Navarrete J, Gallo LI, Parra S, Martínez AD, González-Jamett A, Marengo FD, Cárdenas AM. Gain-of-Function Dynamin-2 Mutations Linked to Centronuclear Myopathy Impair Ca2+-Induced Exocytosis in Human Myoblasts. Int J Mol Sci 2022; 23:ijms231810363. [PMID: 36142275 PMCID: PMC9499313 DOI: 10.3390/ijms231810363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/26/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Gain-of-function mutations of dynamin-2, a mechano-GTPase that remodels membrane and actin filaments, cause centronuclear myopathy (CNM), a congenital disease that mainly affects skeletal muscle tissue. Among these mutations, the variants p.A618T and p.S619L lead to a gain of function and cause a severe neonatal phenotype. By using total internal reflection fluorescence microscopy (TIRFM) in immortalized human myoblasts expressing the pH-sensitive fluorescent protein (pHluorin) fused to the insulin-responsive aminopeptidase IRAP as a reporter of the GLUT4 vesicle trafficking, we measured single pHluorin signals to investigate how p.A618T and p.S619L mutations influence exocytosis. We show here that both dynamin-2 mutations significantly reduced the number and durations of pHluorin signals induced by 10 μM ionomycin, indicating that in addition to impairing exocytosis, they also affect the fusion pore dynamics. These mutations also disrupt the formation of actin filaments, a process that reportedly favors exocytosis. This altered exocytosis might importantly disturb the plasmalemma expression of functional proteins such as the glucose transporter GLUT4 in skeletal muscle cells, impacting the physiology of the skeletal muscle tissue and contributing to the CNM disease.
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Affiliation(s)
- Lucas Bayonés
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - María José Guerra-Fernández
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Fernando Hinostroza
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca 3460000, Chile
- Centro de Investigación en Neuropsicología y Neurociencias Cognitivas (CINPSI Neurocog), Facultad de Ciencias de la Salud, Universidad Católica del Maule, Talca 3460000, Chile
| | - Ximena Báez-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Jacqueline Vásquez-Navarrete
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Luciana I. Gallo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Sergio Parra
- Instituto de Fisiología Celular—Neurociencias, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Arlek González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Fernando D. Marengo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
- Correspondence: (F.D.M.); (A.M.C.)
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Correspondence: (F.D.M.); (A.M.C.)
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5
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Abstract
Fluorescence imaging techniques play a pivotal role in our understanding of the nervous system. The emergence of various super-resolution microscopy methods and specialized fluorescent probes enables direct insight into neuronal structure and protein arrangements in cellular subcompartments with so far unmatched resolution. Super-resolving visualization techniques in neurons unveil a novel understanding of cytoskeletal composition, distribution, motility, and signaling of membrane proteins, subsynaptic structure and function, and neuron-glia interaction. Well-defined molecular targets in autoimmune and neurodegenerative disease models provide excellent starting points for in-depth investigation of disease pathophysiology using novel and innovative imaging methodology. Application of super-resolution microscopy in human brain samples and for testing clinical biomarkers is still in its infancy but opens new opportunities for translational research in neurology and neuroscience. In this review, we describe how super-resolving microscopy has improved our understanding of neuronal and brain function and dysfunction in the last two decades.
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Affiliation(s)
- Christian Werner
- Department of Biotechnology & Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology & Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Christian Geis
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
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Pirnat S, Božić M, Dolanc D, Horvat A, Tavčar P, Vardjan N, Verkhratsky A, Zorec R, Stenovec M. Astrocyte arborization enhances Ca 2+ but not cAMP signaling plasticity. Glia 2021; 69:2899-2916. [PMID: 34406698 PMCID: PMC9290837 DOI: 10.1002/glia.24076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 01/07/2023]
Abstract
The plasticity of astrocytes is fundamental for their principal function, maintaining homeostasis of the central nervous system throughout life, and is associated with diverse exposomal challenges. Here, we used cultured astrocytes to investigate at subcellular level basic cell processes under controlled environmental conditions. We compared astroglial functional and signaling plasticity in standard serum‐containing growth medium, a condition mimicking pathologic conditions, and in medium without serum, favoring the acquisition of arborized morphology. Using opto−/electrophysiologic techniques, we examined cell viability, expression of astroglial markers, vesicle dynamics, and cytosolic Ca2+ and cAMP signaling. The results revealed altered vesicle dynamics in arborized astrocytes that was associated with increased resting [Ca2+]i and increased subcellular heterogeneity in [Ca2+]i, whereas [cAMP]i subcellular dynamics remained stable in both cultures, indicating that cAMP signaling is less prone to plastic remodeling than Ca2+ signaling, possibly also in in vivo contexts.
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Affiliation(s)
- Samo Pirnat
- Laboratory of Cell Engineering, Celica BIOMEDICAL, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Mićo Božić
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Dorian Dolanc
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Anemari Horvat
- Laboratory of Cell Engineering, Celica BIOMEDICAL, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Petra Tavčar
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Nina Vardjan
- Laboratory of Cell Engineering, Celica BIOMEDICAL, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Alexei Verkhratsky
- Laboratory of Cell Engineering, Celica BIOMEDICAL, Ljubljana, Slovenia.,Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Achucarro Center for Neuroscience, IKERBASQUE, Bilbao, Spain
| | - Robert Zorec
- Laboratory of Cell Engineering, Celica BIOMEDICAL, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
| | - Matjaž Stenovec
- Laboratory of Cell Engineering, Celica BIOMEDICAL, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
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7
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Arriagada-Diaz J, Prado-Vega L, Cárdenas Díaz AM, Ardiles AO, Gonzalez-Jamett AM. Dynamin Superfamily at Pre- and Postsynapses: Master Regulators of Synaptic Transmission and Plasticity in Health and Disease. Neuroscientist 2020; 28:41-58. [PMID: 33300419 DOI: 10.1177/1073858420974313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dynamin superfamily proteins (DSPs) comprise a large group of GTP-ases that orchestrate membrane fusion and fission, and cytoskeleton remodeling in different cell-types. At the central nervous system, they regulate synaptic vesicle recycling and signaling-receptor turnover, allowing the maintenance of synaptic transmission. In the presynapses, these GTP-ases control the recycling of synaptic vesicles influencing the size of the ready-releasable pool and the release of neurotransmitters from nerve terminals, whereas in the postsynapses, they are involved in AMPA-receptor trafficking to and from postsynaptic densities, supporting excitatory synaptic plasticity, and consequently learning and memory formation. In agreement with these relevant roles, an important number of neurological disorders are associated with mutations and/or dysfunction of these GTP-ases. Along the present review we discuss the importance of DSPs at synapses and their implication in different neuropathological contexts.
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Affiliation(s)
- Jorge Arriagada-Diaz
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.,Programa de Magister en Ciencias, mención Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Lorena Prado-Vega
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.,Programa de Magister en Ciencias, mención Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Ana M Cárdenas Díaz
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Alvaro O Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.,Centro de Neurología Traslacional, Facultad de Medicina, Universidad de Valparaíso, Valparaíso, Chile.,Centro Interdisciplinario de Estudios en Salud, Facultad de Medicina, Universidad de Valparaíso, Viña del Mar, Chile
| | - Arlek M Gonzalez-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
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8
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Chowdhury HH, Zorec R. Exocytotic fusion pore under stress. Cell Stress 2020; 4:218-226. [PMID: 32908961 PMCID: PMC7453636 DOI: 10.15698/cst2020.09.230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/19/2020] [Accepted: 07/29/2020] [Indexed: 11/13/2022] Open
Abstract
Exocytosis is a universal process of eukaryotic cells, consisting of fusion between the vesicle and the plasma membranes, leading to the formation of a fusion pore, a channel through which vesicle cargo exits into the extracellular space. In 1986, Rand and Parsegian proposed several stages to explain the nature of membrane fusion. Following stimulation, it starts with focused stress destabilization of membranes in contact, followed by the coalescence of two membrane surfaces. In the next fraction of a millisecond, restabilization of fused membranes is considered to occur to maintain the cell's integrity. This view predicted that once a fusion pore is formed, it must widen abruptly, irreversibly and fully, whereby the vesicle membrane completely integrates with and collapses into the plasma membrane (full fusion exocytosis). However, recent experimental evidence has revealed that once the fusion pore opens, it may also reversibly close (transient or kiss-and-run exocytosis). Here, we present a historical perspective on understanding the mechanisms that initiate the membrane merger and fusion pore formation. Next, post-fusion mechanisms that regulate fusion pore stability are considered, reflecting the state in which the forces of widening and constriction of fusion pores are balanced. Although the mechanisms generating these forces are unclear, they may involve lipids and proteins, including SNAREs, which play a role not only in the pre-fusion but also post-fusion stages of exocytosis. How molecules stabilize the fusion pore in the open state is key for a better understanding of fusion pore physiology in health and disease.
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Affiliation(s)
- Helena Haque Chowdhury
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Medical Faculty, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia
- Laboratory of Neuroendocrinology – Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Medical Faculty, 1000 Ljubljana, Slovenia
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9
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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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10
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Davis LC, Morgan AJ, Galione A. NAADP-regulated two-pore channels drive phagocytosis through endo-lysosomal Ca 2+ nanodomains, calcineurin and dynamin. EMBO J 2020; 39:e104058. [PMID: 32510172 PMCID: PMC7360967 DOI: 10.15252/embj.2019104058] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/22/2020] [Accepted: 04/29/2020] [Indexed: 12/15/2022] Open
Abstract
Macrophages clear pathogens by phagocytosis and lysosomes that fuse with phagosomes are traditionally regarded as to a source of membranes and luminal degradative enzymes. Here, we reveal that endo-lysosomes act as platforms for a new phagocytic signalling pathway in which FcγR activation recruits the second messenger NAADP and thereby promotes the opening of Ca2+ -permeable two-pore channels (TPCs). Remarkably, phagocytosis is driven by these local endo-lysosomal Ca2+ nanodomains rather than global cytoplasmic or ER Ca2+ signals. Motile endolysosomes contact nascent phagosomes to promote phagocytosis, whereas endo-lysosome immobilization prevents it. We show that TPC-released Ca2+ rapidly activates calcineurin, which in turn dephosphorylates and activates the GTPase dynamin-2. Finally, we find that different endo-lysosomal Ca2+ channels play diverse roles, with TPCs providing a universal phagocytic signal for a wide range of particles and TRPML1 being only required for phagocytosis of large targets.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford, UK
| | | | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, UK
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11
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Lasič E, Trkov Bobnar S, Wilhelmsson U, Pablo Y, Pekny M, Zorec R, Stenovec M. Nestin affects fusion pore dynamics in mouse astrocytes. Acta Physiol (Oxf) 2020; 228:e13399. [PMID: 31597221 DOI: 10.1111/apha.13399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 09/17/2019] [Accepted: 09/30/2019] [Indexed: 12/15/2022]
Abstract
AIM Astrocytes play a homeostatic role in the central nervous system and influence numerous aspects of neurophysiology via intracellular trafficking of vesicles. Intermediate filaments (IFs), also known as nanofilaments, regulate a number of cellular processes including organelle trafficking and adult hippocampal neurogenesis. We have recently demonstrated that the IF protein nestin, a marker of neural stem cells and immature and reactive astrocytes, is also expressed in some astrocytes in the unchallenged hippocampus and regulates neurogenesis through Notch signalling from astrocytes to neural stem cells, possibly via altered trafficking of vesicles containing the Notch ligand Jagged-1. METHODS We thus investigated whether nestin affects vesicle dynamics in astrocytes by examining single vesicle interactions with the plasmalemma and vesicle trafficking with high-resolution cell-attached membrane capacitance measurements and confocal microscopy. We used cell cultures of astrocytes from nestin-deficient (Nes-/- ) and wild-type (wt) mice, and fluorescent dextran and Fluo-2 to examine vesicle mobility and intracellular Ca2+ concentration respectively. RESULTS Nes-/- astrocytes exhibited altered sizes of vesicles undergoing full fission and transient fusion, altered vesicle fusion pore geometry and kinetics, decreased spontaneous vesicle mobility and altered ATP-evoked mobility. Purinergic stimulation evoked Ca2+ signalling that was slightly attenuated in Nes-/- astrocytes, which exhibited more oscillatory Ca2+ responses than wt astrocytes. CONCLUSION These results demonstrate at the single vesicle level that nestin regulates vesicle interactions with the plasmalemma and vesicle trafficking, indicating its potential role in astrocyte vesicle-based communication.
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Affiliation(s)
- Eva Lasič
- Laboratory of Neuroendocrinology‐Molecular Cell Physiology Institute of Pathophysiology Faculty of Medicine University of Ljubljana Ljubljana Slovenia
| | - Saša Trkov Bobnar
- Laboratory of Neuroendocrinology‐Molecular Cell Physiology Institute of Pathophysiology Faculty of Medicine University of Ljubljana Ljubljana Slovenia
- Celica Biomedical Ljubljana Slovenia
| | - Ulrika Wilhelmsson
- Laboratory of Astrocyte Biology and CNS Regeneration Center for Brain Repair Department of Clinical Neuroscience Institute of Neuroscience and Physiology Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
| | - Yolanda Pablo
- Laboratory of Astrocyte Biology and CNS Regeneration Center for Brain Repair Department of Clinical Neuroscience Institute of Neuroscience and Physiology Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
| | - Milos Pekny
- Laboratory of Astrocyte Biology and CNS Regeneration Center for Brain Repair Department of Clinical Neuroscience Institute of Neuroscience and Physiology Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
- Florey Institute of Neuroscience and Mental Health Parkville Vic. Australia
- University of Newcastle Newcastle NSW Australia
| | - Robert Zorec
- Laboratory of Neuroendocrinology‐Molecular Cell Physiology Institute of Pathophysiology Faculty of Medicine University of Ljubljana Ljubljana Slovenia
- Celica Biomedical Ljubljana Slovenia
| | - Matjaž Stenovec
- Laboratory of Neuroendocrinology‐Molecular Cell Physiology Institute of Pathophysiology Faculty of Medicine University of Ljubljana Ljubljana Slovenia
- Celica Biomedical Ljubljana Slovenia
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12
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Li D, Liu X, Liu T, Liu H, Tong L, Jia S, Wang YF. Neurochemical regulation of the expression and function of glial fibrillary acidic protein in astrocytes. Glia 2019; 68:878-897. [PMID: 31626364 DOI: 10.1002/glia.23734] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/27/2019] [Accepted: 09/17/2019] [Indexed: 12/30/2022]
Abstract
Glial fibrillary acidic protein (GFAP), a type III intermediate filament, is a marker of mature astrocytes. The expression of GFAP gene is regulated by many transcription factors (TFs), mainly Janus kinase-2/signal transducer and activator of transcription 3 cascade and nuclear factor κ-light-chain-enhancer of activated B cell signaling. GFAP expression is also modulated by protein kinase and other signaling molecules that are elicited by neuronal activity and hormones. Abnormal expression of GFAP proteins occurs in neuroinflammation, neurodegeneration, brain edema-eliciting diseases, traumatic brain injury, psychiatric disorders and others. GFAP, mainly in α-isoform, is the major component of cytoskeleton and the scaffold of astrocytes, which is essential for the maintenance of astrocytic structure and shape. GFAP also has highly morphological plasticity because of its quick changes in assembling and polymerizing states in response to environmental challenges. This plasticity and its corresponding cellular morphological changes endow astrocytes the functions of physical barrier between adjacent neurons and stabilizer of extracellular environment. Moreover, GFAP colocalizes and even molecularly associates with many functional molecules. This feature allows GFAP to function as a platform for direct interactions between different molecules. Last, GFAP involves transportation and localization of other functional proteins and thus serves as a protein transport guide in astrocytes. This guiding role of GFAP involves an elastic retraction and extension cytoskeletal network that couples with GFAP reassembling, transporting, and membrane protein recycling machinery. This paper reviews our current understanding of the expression and functions of GFAP as well as their regulation.
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Affiliation(s)
- Dongyang Li
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xiaoyu Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Tianming Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Haitao Liu
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Li Tong
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Shuwei Jia
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Yu-Feng Wang
- Department of Physiology, Harbin Medical University, Harbin, China
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13
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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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14
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Chasing Uptake: Super-Resolution Microscopy in Endocytosis and Phagocytosis. Trends Cell Biol 2019; 29:727-739. [PMID: 31227311 DOI: 10.1016/j.tcb.2019.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/14/2019] [Accepted: 05/23/2019] [Indexed: 11/21/2022]
Abstract
Since their invention about two decades ago, super-resolution microscopes have become a method of choice in cell biology. Owing to a spatial resolution below 50 nm, smaller than the size of most organelles, and an order of magnitude better than the diffraction limit of conventional light microscopes, super-resolution microscopy is a powerful technique for resolving intracellular trafficking. In this review we discuss discoveries in endocytosis and phagocytosis that have been made possible by super-resolution microscopy - from uptake at the plasma membrane, endocytic coat formation, and cytoskeletal rearrangements to endosomal maturation. The detailed visualization of the diverse molecular assemblies that mediate endocytic uptake will provide a better understanding of how cells ingest extracellular material.
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15
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Kitajima Y, Ishii T, Kohda T, Ishizuka M, Yamazaki K, Nishimura Y, Tanaka T, Dan S, Nakajima M. Mechanistic study of PpIX accumulation using the JFCR39 cell panel revealed a role for dynamin 2-mediated exocytosis. Sci Rep 2019; 9:8666. [PMID: 31209282 PMCID: PMC6572817 DOI: 10.1038/s41598-019-44981-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/29/2019] [Indexed: 12/21/2022] Open
Abstract
5-aminolevulinic acid (5-ALA) has recently been employed for photodynamic diagnosis (ALA-PDD) and photodynamic therapy (ALA-PDT) of various types of cancer because hyperproliferating tumor cells do not utilize oxidative phosphorylation and do not efficiently produce heme; instead, they accumulate protoporphyrin IX (PpIX), which is a precursor of heme that is activated by violet light irradiation that results in the production of red fluorescence and singlet oxygen. The efficiencies of ALA-PDD and ALA-PDT depend on the efficient cellular uptake of 5-ALA and the inefficient excretion of PpIX. We employed the JFCR39 cell panel to determine whether tumor cells originating from different tissues can produce and accumulate PpIX. We also investigated cellular factors/molecules involved in PpIX excretion by tumor cells with the JFCR39 cell panel. Unexpectedly, the expression levels of ABCG2, which has been considered to play a major role in PpIX extracellular transport, did not show a strong correlation with PpIX excretion levels in the JFCR39 cell panel, although an ABCG2 inhibitor significantly increased intracellular PpIX accumulation in several tumor cell lines. In contrast, the expression levels of dynamin 2, which is a cell membrane-associated molecule involved in exocytosis, were correlated with the PpIX excretion levels. Moreover, inhibitors of dynamin significantly suppressed PpIX excretion and increased the intracellular levels of PpIX. This is the first report demonstrating the causal relationship between dynamin 2 expression and PpIX excretion in tumor cells.
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Affiliation(s)
| | | | | | | | - Kanami Yamazaki
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japan Foundation for Cancer Research, Tokyo, Japan
| | - Yumiko Nishimura
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japan Foundation for Cancer Research, Tokyo, Japan
| | | | - Shingo Dan
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japan Foundation for Cancer Research, Tokyo, Japan.
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16
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Klein O, Sagi-Eisenberg R. Anaphylactic Degranulation of Mast Cells: Focus on Compound Exocytosis. J Immunol Res 2019; 2019:9542656. [PMID: 31011586 PMCID: PMC6442490 DOI: 10.1155/2019/9542656] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 12/26/2018] [Indexed: 01/15/2023] Open
Abstract
Anaphylaxis is a notorious type 2 immune response which may result in a systemic response and lead to death. A precondition for the unfolding of the anaphylactic shock is the secretion of inflammatory mediators from mast cells in response to an allergen, mostly through activation of the cells via the IgE-dependent pathway. While mast cells are specialized secretory cells that can secrete through a variety of exocytic modes, the most predominant mode exerted by the mast cell during anaphylaxis is compound exocytosis-a specialized form of regulated exocytosis where secretory granules fuse to one another. Here, we review the modes of regulated exocytosis in the mast cell and focus on compound exocytosis. We review historical landmarks in the research of compound exocytosis in mast cells and the methods available for investigating compound exocytosis. We also review the molecular mechanisms reported to underlie compound exocytosis in mast cells and expand further with reviewing key findings from other cell types. Finally, we discuss the possible reasons for the mast cell to utilize compound exocytosis during anaphylaxis, the conflicting evidence in different mast cell models, and the open questions in the field which remain to be answered.
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Affiliation(s)
- Ofir Klein
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ronit Sagi-Eisenberg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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17
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Klein O, Roded A, Hirschberg K, Fukuda M, Galli SJ, Sagi-Eisenberg R. Imaging FITC-dextran as a Reporter for Regulated Exocytosis. J Vis Exp 2018. [PMID: 29985342 DOI: 10.3791/57936] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Regulated exocytosis is a process by which cargo, which is stored in secretory granules (SGs), is released in response to a secretory trigger. Regulated exocytosis is fundamental for intercellular communication and is a key mechanism for the secretion of neurotransmitters, hormones, inflammatory mediators, and other compounds, by a variety of cells. At least three distinct mechanisms are known for regulated exocytosis: full exocytosis, where a single SG fully fuses with the plasma membrane, kiss-and-run exocytosis, where a single SG transiently fuses with the plasma membrane, and compound exocytosis, where several SGs fuse with each other, prior to or after SG fusion with the plasma membrane. The type of regulated exocytosis undertaken by a cell is often dictated by the type of secretory trigger. However, in many cells, a single secretory trigger can activate multiple modes of regulated exocytosis simultaneously. Despite their abundance and importance across cell types and species, the mechanisms that determine the different modes of secretion are largely unresolved. One of the main challenges in investigating the different modes of regulated exocytosis, is the difficulty in distinguishing between them as well as exploring them separately. Here we describe the use of fluorescein isothiocyanate (FITC)-dextran as an exocytosis reporter, and live cell imaging, to differentiate between the different pathways of regulated exocytosis, focusing on compound exocytosis, based on the robustness and duration of the exocytic events.
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Affiliation(s)
- Ofir Klein
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University
| | - Amit Roded
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University
| | - Koret Hirschberg
- Department of Pathology, Sackler Faculty of Medicine, Tel Aviv University
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University
| | - Stephen J Galli
- Departments of Pathology and of Microbiology and Immunology and Sean N. Parker Center for Allergy and Asthma Research, School of Medicine, Stanford University
| | - Ronit Sagi-Eisenberg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University;
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18
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Heller JP, Rusakov DA. The Nanoworld of the Tripartite Synapse: Insights from Super-Resolution Microscopy. Front Cell Neurosci 2017; 11:374. [PMID: 29225567 PMCID: PMC5705901 DOI: 10.3389/fncel.2017.00374] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/10/2017] [Indexed: 12/17/2022] Open
Abstract
Synaptic connections between individual nerve cells are fundamental to the process of information transfer and storage in the brain. Over the past decades a third key partner of the synaptic machinery has been unveiled: ultrathin processes of electrically passive astroglia which often surround pre- and postsynaptic structures. The recent advent of super-resolution (SR) microscopy has begun to uncover the dynamic nanoworld of synapses and their astroglial environment. Here we overview and discuss the current progress in our understanding of the synaptic nanoenvironment, as gleaned from the imaging methods that go beyond the diffraction limit of conventional light microscopy. We argue that such methods are essential to achieve a new level of comprehension pertinent to the principles of signal integration in the brain.
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Affiliation(s)
- Janosch P Heller
- UCL Institute of Neurology, University College London, London, United Kingdom
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, United Kingdom.,Institute of Neuroscience, University of Nizhny Novgorod, Nizhny Novgorod, Russia
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19
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Trouillon R, Letizia MC, Menzies KJ, Mouchiroud L, Auwerx J, Schoonjans K, Gijs MAM. A multiscale study of the role of dynamin in the regulation of glucose uptake. Integr Biol (Camb) 2017; 9:810-819. [DOI: 10.1039/c7ib00015d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cells- and organisms-on-a-chip strategies were used to highlight the role of the molecular motor dynamin in regulating the translocation of specific glucose transporters.
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Affiliation(s)
- Raphaël Trouillon
- Laboratory of Microsystems
- Ecole Polytechnique Fédérale de Lausanne
- EPFL-STI-IMT-LMIS2
- CH-1015 Lausanne
- Switzerland
| | - M. Cristina Letizia
- Laboratory of Microsystems
- Ecole Polytechnique Fédérale de Lausanne
- EPFL-STI-IMT-LMIS2
- CH-1015 Lausanne
- Switzerland
| | - Keir J. Menzies
- Laboratory of Metabolic Signaling
- Ecole Polytechnique Fédérale de Lausanne
- EPFL-SV-IBI-UPSCHOONJANS
- CH-1015 Lausanne
- Switzerland
| | - Laurent Mouchiroud
- Laboratory of Integrative and Systems Physiology
- Ecole Polytechnique Fédérale de Lausanne
- EPFL-SV-IBI-LISP
- CH-1015 Lausanne
- Switzerland
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology
- Ecole Polytechnique Fédérale de Lausanne
- EPFL-SV-IBI-LISP
- CH-1015 Lausanne
- Switzerland
| | - Kristina Schoonjans
- Laboratory of Metabolic Signaling
- Ecole Polytechnique Fédérale de Lausanne
- EPFL-SV-IBI-UPSCHOONJANS
- CH-1015 Lausanne
- Switzerland
| | - Martin A. M. Gijs
- Laboratory of Microsystems
- Ecole Polytechnique Fédérale de Lausanne
- EPFL-STI-IMT-LMIS2
- CH-1015 Lausanne
- Switzerland
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