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Baginska U, Moro A, Toonen RF, Verhage M. Maximal Fusion Capacity and Efficient Replenishment of the Dense Core Vesicle Pool in Hippocampal Neurons. J Neurosci 2023; 43:7616-7625. [PMID: 37852790 PMCID: PMC10634579 DOI: 10.1523/jneurosci.2251-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 10/20/2023] Open
Abstract
Neuropeptides and neurotrophins, stored in dense core vesicles (DCVs), are together the largest currently known group of chemical signals in the brain. Exocytosis of DCVs requires high-frequency or patterned stimulation, but the determinants to reach maximal fusion capacity and for efficient replenishment of released DCVs are unknown. Here, we systematically studied fusion of DCV with single vesicle resolution on different stimulation patterns in mammalian CNS neurons. We show that tetanic stimulation trains of 50-Hz action potential (AP) bursts maximized DCV fusion, with significantly fewer fusion event during later bursts of the train. This difference was omitted by introduction of interburst intervals but did not increase total DCV fusion. Interburst intervals as short as 5 s were sufficient to restore the fusion capacity. Theta burst stimulation (TBS) triggered less DCV fusion than tetanic stimulation, but a similar fusion efficiency per AP. Prepulse stimulation did not alter this. However, low-frequency stimulation (4 Hz) intermitted with fast ripple stimulation (200 APs at 200 Hz) produced substantial DCV fusion, albeit not as much as tetanic stimulation. Finally, individual fusion events had longer durations with more intense stimulation. These data indicate that trains of 50-Hz AP stimulation patterns triggered DCV exocytosis most efficiently and more intense stimulation promotes longer DCV fusion pore openings.SIGNIFICANCE STATEMENT Neuropeptides and neurotrophins modulate multiple regulatory functions of human body like reproduction, food intake or mood. They are packed into dense core vesicles (DCVs) that undergo calcium and action potential (AP) fusion with the plasma membrane. In order to study the fusion of DCVs in vitro, techniques like perfusion with buffer containing high concentration of potassium or electric field stimulation are needed to trigger the exocytosis of DCVs. Here, we studied the relationship between DCVs fusion properties and different electric field stimulation patterns. We used six different stimulation patterns and showed that trains of 50-Hz action potential bursts triggered DCV exocytosis most efficiently and more intense stimulation promotes longer DCV fusion pore openings.
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Affiliation(s)
- Urszula Baginska
- Department of Functional Genomics, Faculty of Exact Science, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and Vrije Universiteit Medical Center, Amsterdam 1081 HV, The Netherlands
| | - Alessandro Moro
- Department of Functional Genomics, Faculty of Exact Science, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and Vrije Universiteit Medical Center, Amsterdam 1081 HV, The Netherlands
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Medical Center, Amsterdam 1105 AZ, The Netherlands
| | - Ruud F Toonen
- Department of Functional Genomics, Faculty of Exact Science, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and Vrije Universiteit Medical Center, Amsterdam 1081 HV, The Netherlands
| | - Matthijs Verhage
- Department of Functional Genomics, Faculty of Exact Science, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and Vrije Universiteit Medical Center, Amsterdam 1081 HV, The Netherlands
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Medical Center, Amsterdam 1105 AZ, The Netherlands
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Batenburg KL, Rohde SK, Cornelissen-Steijger P, Breeuwsma N, Heine VM, Scheper W. A Human Neuron/Astrocyte Co-culture to Model Seeded and Spontaneous Intraneuronal Tau Aggregation. Curr Protoc 2023; 3:e900. [PMID: 37801344 DOI: 10.1002/cpz1.900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Communication and contact between neurons and astrocytes is important for proper brain physiology. How neuron/astrocyte crosstalk is affected by intraneuronal tau aggregation in neurodegenerative tauopathies is largely elusive. Human induced pluripotent stem cell (iPSC)-derived neurons provide the opportunity to model tau pathology in a translationally relevant in vitro context. However, current iPSC models inefficiently develop tau aggregates, and co-culture models of tau pathology have thus far utilized rodent astrocytes. In this article, we describe the co-culture of human iPSC-derived neurons with primary human astrocytes in a 96-well format compatible with high-content microscopy. By lentiviral overexpression of different mutated tau variants, this protocol can be flexibly adapted for the efficient induction of seeded or spontaneous tau aggregation. We used this novel co-culture model to identify cell type-specific disease mechanisms and to provide proof of concept for intervention by antisense therapy. These results show that this human co-culture model provides a highly translational tool for target discovery and drug development for human tauopathies. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Human neuron/astrocyte co-culture for seeded and spontaneous intraneuronal tau aggregation Support Protocol 1: Human induced pluripotent stem cell culture Support Protocol 2: Human primary astrocyte culture.
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Affiliation(s)
- Kevin Llewelyn Batenburg
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience-Neurodegeneration, De Boelelaan, Amsterdam, The Netherlands
| | - Susan Karijn Rohde
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience-Neurodegeneration, De Boelelaan, Amsterdam, The Netherlands
| | - Paulien Cornelissen-Steijger
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Child and Adolescent Psychiatry, Amsterdam Neuroscience, De Boelelaan, Amsterdam, The Netherlands
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, De Boelelaan, Amsterdam, The Netherlands
| | - Nicole Breeuwsma
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Child and Adolescent Psychiatry, Amsterdam Neuroscience, De Boelelaan, Amsterdam, The Netherlands
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, De Boelelaan, Amsterdam, The Netherlands
| | - Vivi Majella Heine
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Child and Adolescent Psychiatry, Amsterdam Neuroscience, De Boelelaan, Amsterdam, The Netherlands
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, De Boelelaan, Amsterdam, The Netherlands
| | - Wiep Scheper
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience-Neurodegeneration, De Boelelaan, Amsterdam, The Netherlands
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Human Genetics, Amsterdam Neuroscience-Neurodegeneration, De Boelelaan, Amsterdam, The Netherlands
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Synaptotagmin 9 Modulates Spontaneous Neurotransmitter Release in Striatal Neurons by Regulating Substance P Secretion. J Neurosci 2023; 43:1475-1491. [PMID: 36732068 PMCID: PMC9992334 DOI: 10.1523/jneurosci.1857-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 02/04/2023] Open
Abstract
Synaptotagmin 9 (SYT9) is a tandem C2 domain Ca2+ sensor for exocytosis in neuroendocrine cells; its function in neurons remains unclear. Here, we show that, in mixed-sex cultures, SYT9 does not trigger rapid synaptic vesicle exocytosis in mouse cortical, hippocampal, or striatal neurons, unless it is massively overexpressed. In striatal neurons, loss of SYT9 reduced the frequency of spontaneous neurotransmitter release events (minis). We delved into the underlying mechanism and discovered that SYT9 was localized to dense-core vesicles that contain substance P (SP). Loss of SYT9 impaired SP release, causing the observed decrease in mini frequency. This model is further supported by loss of function mutants. Namely, Ca2+ binding to the C2A domain of SYT9 triggered membrane fusion in vitro, and mutations that disrupted this activity abolished the ability of SYT9 to regulate both SP release and mini frequency. We conclude that SYT9 indirectly regulates synaptic transmission in striatal neurons by controlling SP release.SIGNIFICANCE STATEMENT Synaptotagmin 9 (SYT9) has been described as a Ca2+ sensor for dense-core vesicle (DCV) exocytosis in neuroendocrine cells, but its role in neurons remains unclear, despite widespread expression in the brain. This article examines the role of SYT9 in synaptic transmission across cultured cortical, hippocampal, and striatal neuronal preparations. We found that SYT9 regulates spontaneous neurotransmitter release in striatal neurons by serving as a Ca2+ sensor for the release of the neuromodulator substance P from DCVs. This demonstrates a novel role for SYT9 in neurons and uncovers a new field of study into neuromodulation by SYT9, a protein that is widely expressed in the brain.
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Girven KS, Mangieri L, Bruchas MR. Emerging approaches for decoding neuropeptide transmission. Trends Neurosci 2022; 45:899-912. [PMID: 36257845 PMCID: PMC9671847 DOI: 10.1016/j.tins.2022.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/14/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022]
Abstract
Neuropeptides produce robust effects on behavior across species, and recent research has benefited from advances in high-resolution techniques to investigate peptidergic transmission and expression throughout the brain in model systems. Neuropeptides exhibit distinct characteristics which includes their post-translational processing, release from dense core vesicles, and ability to activate G-protein-coupled receptors (GPCRs). These complex properties have driven the need for development of specialized tools that can sense neuropeptide expression, cell activity, and release. Current research has focused on isolating when and how neuropeptide transmission occurs, as well as the conditions in which neuropeptides directly mediate physiological and adaptive behavioral states. Here we describe the current technological landscape in which the field is operating to decode key questions regarding these dynamic neuromodulators.
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Affiliation(s)
- Kasey S Girven
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA; University of Washington Center for the Neurobiology of Addiction, Pain, and Emotion, Seattle, WA, USA; Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Leandra Mangieri
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA; University of Washington Center for the Neurobiology of Addiction, Pain, and Emotion, Seattle, WA, USA
| | - Michael R Bruchas
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA; University of Washington Center for the Neurobiology of Addiction, Pain, and Emotion, Seattle, WA, USA; Department of Pharmacology, University of Washington, Seattle, WA, USA.
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Tang F, Fan J, Zhang X, Zou Z, Xiao D, Li X. The Role of Vti1a in Biological Functions and Its Possible Role in Nervous System Disorders. Front Mol Neurosci 2022; 15:918664. [PMID: 35711736 PMCID: PMC9197314 DOI: 10.3389/fnmol.2022.918664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/09/2022] [Indexed: 11/24/2022] Open
Abstract
Vesicle transport through interaction with t-SNAREs 1A (Vti1a), a member of the N-ethylmaleimide-sensitive factor attachment protein receptor protein family, is involved in cell signaling as a vesicular protein and mediates vesicle trafficking. Vti1a appears to have specific roles in neurons, primarily by regulating upstream neurosecretory events that mediate exocytotic proteins and the availability of secretory organelles, as well as regulating spontaneous synaptic transmission and postsynaptic efficacy to control neurosecretion. Vti1a also has essential roles in neural development, autophagy, and unconventional extracellular transport of neurons. Studies have shown that Vti1a dysfunction plays critical roles in pathological mechanisms of Hepatic encephalopathy by influencing spontaneous neurotransmission. It also may have an unknown role in amyotrophic lateral sclerosis. A VTI1A variant is associated with the risk of glioma, and the fusion product of the VTI1A gene and the adjacent TCF7L2 gene is involved in glioma development. This review summarizes Vti1a functions in neurons and highlights the role of Vti1a in the several nervous system disorders.
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Affiliation(s)
- Fajuan Tang
- Department of Emergency, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Jiali Fan
- Department of Emergency, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Xiaoyan Zhang
- Department of Emergency, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Zhuan Zou
- Department of Emergency, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Dongqiong Xiao
- Department of Emergency, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
- Dongqiong Xiao,
| | - Xihong Li
- Department of Emergency, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
- *Correspondence: Xihong Li,
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Moro A, van Nifterick A, Toonen RF, Verhage M. Dynamin controls neuropeptide secretion by organizing dense-core vesicle fusion sites. SCIENCE ADVANCES 2021; 7:eabf0659. [PMID: 34020952 PMCID: PMC8139595 DOI: 10.1126/sciadv.abf0659] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 04/02/2021] [Indexed: 05/13/2023]
Abstract
Synaptic vesicles (SVs) release neurotransmitters at specialized active zones, but release sites and organizing principles for the other major secretory pathway, neuropeptide/neuromodulator release from dense-core vesicles (DCVs), remain elusive. We identify dynamins, yeast Vps1 orthologs, as DCV fusion site organizers in mammalian neurons. Genetic or pharmacological inactivation of all three dynamins strongly impaired DCV exocytosis, while SV exocytosis remained unaffected. Wild-type dynamin restored normal exocytosis but not guanosine triphosphatase-deficient or membrane-binding mutants that cause neurodevelopmental syndromes. During prolonged stimulation, repeated use of the same DCV fusion location was impaired in dynamin 1-3 triple knockout neurons. The syntaxin-1 staining efficiency, but not its expression level, was reduced. αSNAP (α-soluble N-ethylmaleimide-sensitive factor attachment protein) expression restored this. We conclude that mammalian dynamins organize DCV fusion sites, downstream of αSNAP, by regulating the equilibrium between fusogenic and non-fusogenic syntaxin-1 promoting its availability for SNARE (SNAP receptor) complex formation and DCV exocytosis.
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Affiliation(s)
- Alessandro Moro
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Medical Center, Amsterdam, Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, de Boelelaan 1087, 1081 HV Amsterdam, Netherlands
| | - Anne van Nifterick
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, de Boelelaan 1087, 1081 HV Amsterdam, Netherlands
| | - Ruud F Toonen
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, de Boelelaan 1087, 1081 HV Amsterdam, Netherlands.
| | - Matthijs Verhage
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Medical Center, Amsterdam, Netherlands.
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, de Boelelaan 1087, 1081 HV Amsterdam, Netherlands
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