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de Ceglia R, Ledonne A, Litvin DG, Lind BL, Carriero G, Latagliata EC, Bindocci E, Di Castro MA, Savtchouk I, Vitali I, Ranjak A, Congiu M, Canonica T, Wisden W, Harris K, Mameli M, Mercuri N, Telley L, Volterra A. Specialized astrocytes mediate glutamatergic gliotransmission in the CNS. Nature 2023; 622:120-129. [PMID: 37674083 PMCID: PMC10550825 DOI: 10.1038/s41586-023-06502-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/31/2023] [Indexed: 09/08/2023]
Abstract
Multimodal astrocyte-neuron communications govern brain circuitry assembly and function1. For example, through rapid glutamate release, astrocytes can control excitability, plasticity and synchronous activity2,3 of synaptic networks, while also contributing to their dysregulation in neuropsychiatric conditions4-7. For astrocytes to communicate through fast focal glutamate release, they should possess an apparatus for Ca2+-dependent exocytosis similar to neurons8-10. However, the existence of this mechanism has been questioned11-13 owing to inconsistent data14-17 and a lack of direct supporting evidence. Here we revisited the astrocyte glutamate exocytosis hypothesis by considering the emerging molecular heterogeneity of astrocytes18-21 and using molecular, bioinformatic and imaging approaches, together with cell-specific genetic tools that interfere with glutamate exocytosis in vivo. By analysing existing single-cell RNA-sequencing databases and our patch-seq data, we identified nine molecularly distinct clusters of hippocampal astrocytes, among which we found a notable subpopulation that selectively expressed synaptic-like glutamate-release machinery and localized to discrete hippocampal sites. Using GluSnFR-based glutamate imaging22 in situ and in vivo, we identified a corresponding astrocyte subgroup that responds reliably to astrocyte-selective stimulations with subsecond glutamate release events at spatially precise hotspots, which were suppressed by astrocyte-targeted deletion of vesicular glutamate transporter 1 (VGLUT1). Furthermore, deletion of this transporter or its isoform VGLUT2 revealed specific contributions of glutamatergic astrocytes in cortico-hippocampal and nigrostriatal circuits during normal behaviour and pathological processes. By uncovering this atypical subpopulation of specialized astrocytes in the adult brain, we provide insights into the complex roles of astrocytes in central nervous system (CNS) physiology and diseases, and identify a potential therapeutic target.
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Affiliation(s)
- Roberta de Ceglia
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Ada Ledonne
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Department of Experimental Neuroscience, IRCCS Santa Lucia Foundation, Rome, Italy
| | - David Gregory Litvin
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Wyss Center for Bio and Neuro Engineering, Campus Biotech, Geneva, Switzerland
| | - Barbara Lykke Lind
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Giovanni Carriero
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | | | - Erika Bindocci
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | | | - Iaroslav Savtchouk
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - Ilaria Vitali
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Anurag Ranjak
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Mauro Congiu
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Tara Canonica
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - William Wisden
- Department of Life Sciences and UK Dementia Research Institute, Imperial College London, London, UK
| | - Kenneth Harris
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Manuel Mameli
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Nicola Mercuri
- Department of Experimental Neuroscience, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Ludovic Telley
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland.
| | - Andrea Volterra
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland.
- Wyss Center for Bio and Neuro Engineering, Campus Biotech, Geneva, Switzerland.
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2
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Yu SP, Jiang MQ, Shim SS, Pourkhodadad S, Wei L. Extrasynaptic NMDA receptors in acute and chronic excitotoxicity: implications for preventive treatments of ischemic stroke and late-onset Alzheimer's disease. Mol Neurodegener 2023; 18:43. [PMID: 37400870 DOI: 10.1186/s13024-023-00636-1] [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: 10/12/2022] [Accepted: 06/01/2023] [Indexed: 07/05/2023] Open
Abstract
Stroke and late-onset Alzheimer's disease (AD) are risk factors for each other; the comorbidity of these brain disorders in aging individuals represents a significant challenge in basic research and clinical practice. The similarities and differences between stroke and AD in terms of pathogenesis and pathophysiology, however, have rarely been comparably reviewed. Here, we discuss the research background and recent progresses that are important and informative for the comorbidity of stroke and late-onset AD and related dementia (ADRD). Glutamatergic NMDA receptor (NMDAR) activity and NMDAR-mediated Ca2+ influx are essential for neuronal function and cell survival. An ischemic insult, however, can cause rapid increases in glutamate concentration and excessive activation of NMDARs, leading to swift Ca2+ overload in neuronal cells and acute excitotoxicity within hours and days. On the other hand, mild upregulation of NMDAR activity, commonly seen in AD animal models and patients, is not immediately cytotoxic. Sustained NMDAR hyperactivity and Ca2+ dysregulation lasting from months to years, nevertheless, can be pathogenic for slowly evolving events, i.e. degenerative excitotoxicity, in the development of AD/ADRD. Specifically, Ca2+ influx mediated by extrasynaptic NMDARs (eNMDARs) and a downstream pathway mediated by transient receptor potential cation channel subfamily M member (TRPM) are primarily responsible for excitotoxicity. On the other hand, the NMDAR subunit GluN3A plays a "gatekeeper" role in NMDAR activity and a neuroprotective role against both acute and chronic excitotoxicity. Thus, ischemic stroke and AD share an NMDAR- and Ca2+-mediated pathogenic mechanism that provides a common receptor target for preventive and possibly disease-modifying therapies. Memantine (MEM) preferentially blocks eNMDARs and was approved by the Federal Drug Administration (FDA) for symptomatic treatment of moderate-to-severe AD with variable efficacy. According to the pathogenic role of eNMDARs, it is conceivable that MEM and other eNMDAR antagonists should be administered much earlier, preferably during the presymptomatic phases of AD/ADRD. This anti-AD treatment could simultaneously serve as a preconditioning strategy against stroke that attacks ≥ 50% of AD patients. Future research on the regulation of NMDARs, enduring control of eNMDARs, Ca2+ homeostasis, and downstream events will provide a promising opportunity to understand and treat the comorbidity of AD/ADRD and stroke.
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Affiliation(s)
- Shan P Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Center for Visual & Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, 30033, USA.
| | - Michael Q Jiang
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Center for Visual & Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, 30033, USA
| | - Seong S Shim
- Center for Visual & Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, 30033, USA
| | - Soheila Pourkhodadad
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Center for Visual & Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, 30033, USA
| | - Ling Wei
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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3
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Lai BQ, Wu RJ, Han WT, Bai YR, Liu JL, Yu HY, Yang SB, Wang LJ, Ren JL, Ding Y, Li G, Zeng X, Ma YH, Quan Q, Xing LY, Jiang B, Wang YQ, Zhang L, Chen ZH, Zhang HB, Chen YF, Zheng QJ, Zeng YS. Tail nerve electrical stimulation promoted the efficiency of transplanted spinal cord-like tissue as a neuronal relay to repair the motor function of rats with transected spinal cord injury. Biomaterials 2023; 297:122103. [PMID: 37028111 DOI: 10.1016/j.biomaterials.2023.122103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/19/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023]
Abstract
Following transected spinal cord injury (SCI), there is a critical need to restore nerve conduction at the injury site and activate the silent neural circuits caudal to the injury to promote the recovery of voluntary movement. In this study, we generated a rat model of SCI, constructed neural stem cell (NSC)-derived spinal cord-like tissue (SCLT), and evaluated its ability to replace injured spinal cord and repair nerve conduction in the spinal cord as a neuronal relay. The lumbosacral spinal cord was further activated with tail nerve electrical stimulation (TNES) as a synergistic electrical stimulation to better receive the neural information transmitted by the SCLT. Next, we investigated the neuromodulatory mechanism underlying the action of TNES and its synergism with SCLT in SCI repair. TNES promoted the regeneration and remyelination of axons and increased the proportion of glutamatergic neurons in SCLT to transmit brain-derived neural information more efficiently to the caudal spinal cord. TNES also increased the innervation of motor neurons to hindlimb muscle and improved the microenvironment of muscle tissue, resulting in effective prevention of hindlimb muscle atrophy and enhanced muscle mitochondrial energy metabolism. Tracing of the neural circuits of the sciatic nerve and tail nerve identified the mechanisms responsible for the synergistic effects of SCLT transplantation and TNES in activating central pattern generator (CPG) neural circuits and promoting voluntary motor function recovery in rats. The combination of SCLT and TNES is expected to provide a new breakthrough for patients with SCI to restore voluntary movement and control their muscles.
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Affiliation(s)
- Bi-Qin Lai
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, 510080, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China; Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China; Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Rong-Jie Wu
- Department of Orthopedics, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510100, China; Shantou University Medical College, Shantou, 515041, China
| | - Wei-Tao Han
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Yu-Rong Bai
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, 510080, China
| | - Jia-Lin Liu
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, 510080, China
| | - Hai-Yang Yu
- Department of Orthopedics, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510100, China
| | - Shang-Bin Yang
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, 510080, China
| | - Lai-Jian Wang
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Jia-Le Ren
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Ying Ding
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, 510080, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China; Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Ge Li
- Medical Research Center, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Science, Guangzhou, 510100, China
| | - Xiang Zeng
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, 510080, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China; Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Yuan-Huan Ma
- Guangzhou Institute of Clinical Medicine, Guangzhou First People's Hospital, South China University of Technology, Guangzhou, 510180, China
| | - Qi Quan
- Department of Orthopedic Surgery, Key Laboratory of Musculoskeletal Trauma & War Injuries PLA, Beijing Key Lab of Regenerative Medicine in Orthopedics, the 4th Medical Centre, Chinese PLA General Hospital, Beijing, 100048, China
| | - Ling-Yan Xing
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Bin Jiang
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Ya-Qiong Wang
- Department of Electron Microscope, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Ling Zhang
- Department of Geriatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, China
| | - Zheng-Hong Chen
- Department of Geriatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, China
| | - Hong-Bo Zhang
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Yuan-Feng Chen
- Department of Orthopedics, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510100, China.
| | - Qiu-Jian Zheng
- Department of Orthopedics, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510100, China.
| | - Yuan-Shan Zeng
- Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Ministry of Education, Guangzhou, 510080, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China; Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China; Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China; Institute of Spinal Cord Injury, Sun Yat-sen University, Guangzhou, 510800, China.
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4
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Hao Y, Toulmé E, König B, Rosenmund C, Plested AJR. Targeted sensors for glutamatergic neurotransmission. eLife 2023; 12:84029. [PMID: 36622100 PMCID: PMC9917459 DOI: 10.7554/elife.84029] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023] Open
Abstract
Optical report of neurotransmitter release allows visualisation of excitatory synaptic transmission. Sensitive genetically-encoded fluorescent glutamate reporters operating with a range of affinities and emission wavelengths are available. However, without targeting to synapses, the specificity of the fluorescent signal is uncertain, compared to sensors directed at vesicles or other synaptic markers. We fused the state-of-the-art reporter iGluSnFR to glutamate receptor auxiliary proteins in order to target it to postsynaptic sites. Chimeras of Stargazin and gamma-8 that we named SnFR-γ2 and SnFR-γ8, were enriched at synapses, retained function and reported spontaneous glutamate release in rat hippocampal cells, with apparently diffraction-limited spatial precision. In autaptic mouse neurons cultured on astrocytic microislands, evoked neurotransmitter release could be quantitatively detected at tens of synapses in a field of view whilst evoked currents were recorded simultaneously. These experiments revealed a specific postsynaptic deficit from Stargazin overexpression, resulting in synapses with normal neurotransmitter release but without postsynaptic responses. This defect was reverted by delaying overexpression. By working at different calcium concentrations, we determined that SnFR-γ2 is a linear reporter of the global quantal parameters and short-term synaptic plasticity, whereas iGluSnFR is not. On average, half of iGluSnFR regions of interest (ROIs) showing evoked fluorescence changes had intense rundown, whereas less than 5% of SnFR-γ2 ROIs did. We provide an open-source analysis suite for extracting quantal parameters including release probability from fluorescence time series of individual and grouped synaptic responses. Taken together, postsynaptic targeting improves several properties of iGluSnFR and further demonstrates the importance of subcellular targeting for optogenetic actuators and reporters.
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Affiliation(s)
- Yuchen Hao
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
| | - Estelle Toulmé
- Institute for Neurophysiology, Charité - Universitätsmedizin BerlinBerlinGermany
| | - Benjamin König
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
| | - Christian Rosenmund
- Institute for Neurophysiology, Charité - Universitätsmedizin BerlinBerlinGermany
- NeuroCure Cluster of ExcellenceBerlinGermany
| | - Andrew JR Plested
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
- NeuroCure Cluster of ExcellenceBerlinGermany
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5
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Vesicular release probability sets the strength of individual Schaffer collateral synapses. Nat Commun 2022; 13:6126. [PMID: 36253353 PMCID: PMC9576736 DOI: 10.1038/s41467-022-33565-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 09/22/2022] [Indexed: 12/24/2022] Open
Abstract
Information processing in the brain is controlled by quantal release of neurotransmitters, a tightly regulated process. From ultrastructural analysis, it is known that presynaptic boutons along single axons differ in the number of vesicles docked at the active zone. It is not clear whether the probability of these vesicles to get released (pves) is homogenous or also varies between individual boutons. Here, we optically measure evoked transmitter release at individual Schaffer collateral synapses at different calcium concentrations, using the genetically encoded glutamate sensor iGluSnFR. Fitting a binomial model to measured response amplitude distributions allowed us to extract the quantal parameters N, pves, and q. We find that Schaffer collateral boutons typically release single vesicles under low pves conditions and switch to multivesicular release in high calcium saline. The potency of individual boutons is highly correlated with their vesicular release probability while the number of releasable vesicles affects synaptic output only under high pves conditions.
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6
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Bulumulla C, Krasley AT, Cristofori-Armstrong B, Valinsky WC, Walpita D, Ackerman D, Clapham DE, Beyene AG. Visualizing synaptic dopamine efflux with a 2D composite nanofilm. eLife 2022; 11:78773. [PMID: 35786443 PMCID: PMC9363124 DOI: 10.7554/elife.78773] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 07/01/2022] [Indexed: 11/23/2022] Open
Abstract
Chemical neurotransmission constitutes one of the fundamental modalities of communication between neurons. Monitoring release of these chemicals has traditionally been difficult to carry out at spatial and temporal scales relevant to neuron function. To understand chemical neurotransmission more fully, we need to improve the spatial and temporal resolutions of measurements for neurotransmitter release. To address this, we engineered a chemi-sensitive, two-dimensional composite nanofilm that facilitates visualization of the release and diffusion of the neurochemical dopamine with synaptic resolution, quantal sensitivity, and simultaneously from hundreds of release sites. Using this technology, we were able to monitor the spatiotemporal dynamics of dopamine release in dendritic processes, a poorly understood phenomenon. We found that dopamine release is broadcast from a subset of dendritic processes as hotspots that have a mean spatial spread of ≈ 3.2 µm (full width at half maximum [FWHM]) and are observed with a mean spatial frequency of one hotspot per ≈ 7.5 µm of dendritic length. Major dendrites of dopamine neurons and fine dendritic processes, as well as dendritic arbors and dendrites with no apparent varicose morphology participated in dopamine release. Remarkably, these release hotspots co-localized with Bassoon, suggesting that Bassoon may contribute to organizing active zones in dendrites, similar to its role in axon terminals. To form the vast and complex network necessary for an organism to sense and react to the world, neurons must connect at highly specialized junctions. Individual cells communicate at these ‘synapses’ by releasing chemical signals (or neurotransmitters) such as dopamine, a molecule involved in learning and motivation. Despite the central role that synapses play in the brain, it remains challenging to measure exactly where neurotransmitters are released and how far they travel from their release site. Currently, most tools available to scientists only allow bulk measurements of neurotransmitter release. To tackle this limitation, Bulumulla et al. developed a new way to measure neurotransmitter release from neurons, harnessing a technique which uses fluorescent nanosensors that glow brighter when exposed to dopamine. These sensors form a very thin film upon which neurons can grow; when the cells release dopamine, the sensors ‘light up’ as they encounter the molecule. Dubbed DopaFilm, the technology reveals exactly where the neurotransmitter comes from and how it spreads between cells in real time. In particular, the approach showed that dopamine emerges from 'hot spots' at specific sites in cells; it also helped Bulumulla et al. study how dopamine is released from subcellular compartments that have previously not been well characterized. Improving the sensors so that the film could detect other neurotransmitters besides dopamine would broaden the use of this approach. In the future, combining this technology with other types of imaging should enable studies of individual synapses with intricate detail.
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7
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Mendonça PRF, Tagliatti E, Langley H, Kotzadimitriou D, Zamora-Chimal CG, Timofeeva Y, Volynski KE. Asynchronous glutamate release is enhanced in low release efficacy synapses and dispersed across the active zone. Nat Commun 2022; 13:3497. [PMID: 35715404 PMCID: PMC9206079 DOI: 10.1038/s41467-022-31070-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 05/31/2022] [Indexed: 11/09/2022] Open
Abstract
The balance between fast synchronous and delayed asynchronous release of neurotransmitters has a major role in defining computational properties of neuronal synapses and regulation of neuronal network activity. However, how it is tuned at the single synapse level remains poorly understood. Here, using the fluorescent glutamate sensor SF-iGluSnFR, we image quantal vesicular release in tens to hundreds of individual synaptic outputs from single pyramidal cells with 4 millisecond temporal and 75 nm spatial resolution. We find that the ratio between synchronous and asynchronous synaptic vesicle exocytosis varies extensively among synapses supplied by the same axon, and that the synchronicity of release is reduced at low release probability synapses. We further demonstrate that asynchronous exocytosis sites are more widely distributed within the release area than synchronous sites. Together, our results reveal a universal relationship between the two major functional properties of synapses - the timing and the overall efficacy of neurotransmitter release.
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Affiliation(s)
- Philipe R F Mendonça
- University College London Institute of Neurology, London, UK. .,Department of Physiology and Biophysics, Federal University of Minas Gerais, Gerais, Brazil.
| | - Erica Tagliatti
- University College London Institute of Neurology, London, UK
| | - Helen Langley
- University College London Institute of Neurology, London, UK
| | | | | | - Yulia Timofeeva
- University College London Institute of Neurology, London, UK. .,Department of Computer Science, University of Warwick, Coventry, UK.
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8
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Tjahjono N, Jin Y, Hsu A, Roukes M, Tian L. Letting the little light of mind shine: Advances and future directions in neurochemical detection. Neurosci Res 2022; 179:65-78. [PMID: 34861294 PMCID: PMC9508992 DOI: 10.1016/j.neures.2021.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022]
Abstract
Synaptic transmission via neurochemical release is the fundamental process that integrates and relays encoded information in the brain to regulate physiological function, cognition, and emotion. To unravel the biochemical, biophysical, and computational mechanisms of signal processing, one needs to precisely measure the neurochemical release dynamics with molecular and cell-type specificity and high resolution. Here we reviewed the development of analytical, electrochemical, and fluorescence imaging approaches to detect neurotransmitter and neuromodulator release. We discussed the advantages and practicality in implementation of each technology for ease-of-use, flexibility for multimodal studies, and challenges for future optimization. We hope this review will provide a versatile guide for tool engineering and applications for recording neurochemical release.
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Affiliation(s)
- Nikki Tjahjono
- Biomedical Engineering Graduate Group, University of California, Davis, Davis, CA, 95616, USA
| | - Yihan Jin
- Neuroscience Graduate Group, University of California, Davis, Davis, CA, 95618, USA
| | - Alice Hsu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Michael Roukes
- Department of Physics, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, 95616, USA.
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9
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Müller JA, Betzin J, Santos-Tejedor J, Mayer A, Oprişoreanu AM, Engholm-Keller K, Paulußen I, Gulakova P, McGovern TD, Gschossman LJ, Schönhense E, Wark JR, Lamprecht A, Becker AJ, Waardenberg AJ, Graham ME, Dietrich D, Schoch S. A presynaptic phosphosignaling hub for lasting homeostatic plasticity. Cell Rep 2022; 39:110696. [PMID: 35443170 DOI: 10.1016/j.celrep.2022.110696] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/26/2021] [Accepted: 03/29/2022] [Indexed: 11/29/2022] Open
Abstract
Stable function of networks requires that synapses adapt their strength to levels of neuronal activity, and failure to do so results in cognitive disorders. How such homeostatic regulation may be implemented in mammalian synapses remains poorly understood. Here we show that the phosphorylation status of several positions of the active-zone (AZ) protein RIM1 are relevant for synaptic glutamate release. Position RIMS1045 is necessary and sufficient for expression of silencing-induced homeostatic plasticity and is kept phosphorylated by serine arginine protein kinase 2 (SRPK2). SRPK2-induced upscaling of synaptic release leads to additional RIM1 nanoclusters and docked vesicles at the AZ and is not observed in the absence of RIM1 and occluded by RIMS1045E. Our data suggest that SRPK2 and RIM1 represent a presynaptic phosphosignaling hub that is involved in the homeostatic balance of synaptic coupling of neuronal networks.
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Affiliation(s)
- Johannes Alexander Müller
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany; Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Julia Betzin
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Jorge Santos-Tejedor
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Annika Mayer
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Ana-Maria Oprişoreanu
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Kasper Engholm-Keller
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark; Synapse Proteomics, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | | | - Polina Gulakova
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany; Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | | | - Lena Johanna Gschossman
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany; Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Eva Schönhense
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Jesse R Wark
- Synapse Proteomics, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | - Alf Lamprecht
- Department of Pharmaceutics, Bonn University, Bonn, Germany
| | - Albert J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Ashley J Waardenberg
- Australian Institute for Tropical Health and Medicine, James Cook University, Smithfield, QLD 4878, Australia; i-Synapse, Cairns, QLD, Australia
| | - Mark E Graham
- Synapse Proteomics, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | - Dirk Dietrich
- Department of Neurosurgery, University Hospital Bonn, Bonn, Germany.
| | - Susanne Schoch
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany.
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10
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San Martín A, Arce-Molina R, Aburto C, Baeza-Lehnert F, Barros LF, Contreras-Baeza Y, Pinilla A, Ruminot I, Rauseo D, Sandoval PY. Visualizing physiological parameters in cells and tissues using genetically encoded indicators for metabolites. Free Radic Biol Med 2022; 182:34-58. [PMID: 35183660 DOI: 10.1016/j.freeradbiomed.2022.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023]
Abstract
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
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Affiliation(s)
- A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile.
| | - R Arce-Molina
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - C Aburto
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Y Contreras-Baeza
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - A Pinilla
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - D Rauseo
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile
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11
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Hao Y, Plested AJ. Seeing glutamate at central synapses. J Neurosci Methods 2022; 375:109531. [DOI: 10.1016/j.jneumeth.2022.109531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 12/15/2022]
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12
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Matthews EA, Sun W, McMahon SM, Doengi M, Halka L, Anders S, Müller JA, Steinlein P, Vana NS, van Dyk G, Pitsch J, Becker AJ, Pfeifer A, Kavalali ET, Lamprecht A, Henneberger C, Stein V, Schoch S, Dietrich D. Optical analysis of glutamate spread in the neuropil. Cereb Cortex 2022; 32:3669-3689. [PMID: 35059716 PMCID: PMC9433421 DOI: 10.1093/cercor/bhab440] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/03/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022] Open
Abstract
Fast synaptic communication uses diffusible transmitters whose spread is limited by uptake mechanisms. However, on the submicron-scale, the distance between two synapses, the extent of glutamate spread has so far remained difficult to measure. Here, we show that quantal glutamate release from individual hippocampal synapses activates extracellular iGluSnFr molecules at a distance of >1.5 μm. 2P-glutamate uncaging near spines further showed that alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-Rs and N-methyl-D-aspartate (NMDA)-Rs respond to distant uncaging spots at approximately 800 and 2000 nm, respectively, when releasing the amount of glutamate contained in approximately five synaptic vesicles. The uncaging-induced remote activation of AMPA-Rs was facilitated by blocking glutamate transporters but only modestly decreased by elevating the recording temperature. When mimicking release from neighboring synapses by three simultaneous uncaging spots in the microenvironment of a spine, AMPA-R-mediated responses increased supra-additively. Interfering with extracellular glutamate diffusion through a glutamate scavenger system weakly reduced field synaptic responses but not the quantal amplitude. Together, our data suggest that the neuropil is more permissive to short-range spread of transmitter than suggested by theory, that multivesicular release could regularly coactivate nearest neighbor synapses and that on this scale glutamate buffering by transporters primarily limits the spread of transmitter and allows for cooperative glutamate signaling in extracellular microdomains.
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Affiliation(s)
| | | | | | - M Doengi
- Institute of Physiology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - L Halka
- Institute of Physiology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - S Anders
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - J A Müller
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, 53127 Bonn, Germany
| | - P Steinlein
- Department of Neurosurgery, University Hospital Bonn, 53127 Bonn, Germany,Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Bonn, Germany
| | - N S Vana
- Department of Neurosurgery, University Hospital Bonn, 53127 Bonn, Germany
| | - G van Dyk
- Department of Neurosurgery, University Hospital Bonn, 53127 Bonn, Germany
| | - J Pitsch
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, 53127 Bonn, Germany,Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - A J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, 53127 Bonn, Germany,Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - A Pfeifer
- Institute of Pharmacology and Toxicology, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - E T Kavalali
- Department of Pharmacology, The Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - A Lamprecht
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Bonn, Germany
| | - C Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany,German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany,Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - V Stein
- Institute of Physiology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - S Schoch
- Address correspondence to Prof. Dr Dirk Dietrich, Department of Neurosurgery, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany. ; and Prof. Dr Susanne Schoch, Institute of Neuropathology, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany.
| | - D Dietrich
- Address correspondence to Prof. Dr Dirk Dietrich, Department of Neurosurgery, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany. ; and Prof. Dr Susanne Schoch, Institute of Neuropathology, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany.
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13
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Dürst CD, Oertner TG. Imaging Synaptic Glutamate Release with Two-Photon Microscopy in Organotypic Slice Cultures. Methods Mol Biol 2022; 2417:205-219. [PMID: 35099802 DOI: 10.1007/978-1-0716-1916-2_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The strength of an excitatory synapse relies on the amount of glutamate it releases and on the amount of postsynaptic receptors responding to the released glutamate. Here we describe a strategy to investigate presynaptic release independently of postsynaptic receptors, using a genetically encoded glutamate indicator (GEGI) such as iGluSnFR to measure synaptic transmission in rodent organotypic slice cultures. We express the iGluSnFR in CA3 pyramidal cells and perform two-photon glutamate imaging on individual Schaffer collateral boutons in CA1. Sparse labeling is achieved via transfection of pyramidal cells in organotypic hippocampal cultures, and imaging of evoked glutamate transients with two-photon laser scanning microscopy. A spiral scan path over an individual presynaptic bouton allows to sample at high temporal resolution the local release site in order to capture the peak of iGluSnFR transients.
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Affiliation(s)
- Céline D Dürst
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, Hamburg, Germany.
- Department of Basic Neurosciences, University Medical Center, Geneva, Switzerland.
| | - Thomas G Oertner
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, Hamburg, Germany
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14
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Abstract
Glutamatergic neurotransmission is a widespread form of synaptic excitation in the mammalian brain. The development of genetically encoded fluorescent glutamate sensors allows monitoring synaptic signaling in living brain tissue in real time. Here, we describe single- and two-photon imaging of synaptically evoked glutamatergic population signals in acute hippocampal slices expressing the fluorescent glutamate sensor SF-iGluSnFR.A184S in CA1 or CA3 pyramidal neurons. The protocol can be readily used to study defective synaptic glutamate signaling in mouse models of neuropsychiatric disorders, such as Alzheimer disease. For complete details on the use and execution of this protocol, please refer to Zott et al. (2019).
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15
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Stellon D, Tran MTN, Talbot J, Chear S, Khalid MKNM, Pébay A, Vickers JC, King AE, Hewitt AW, Cook AL. CRISPR/Cas-Mediated Knock-in of Genetically Encoded Fluorescent Biosensors into the AAVS1 Locus of Human-Induced Pluripotent Stem Cells. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2549:379-398. [PMID: 34505269 DOI: 10.1007/7651_2021_422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Genetically encoded fluorescent biosensors (GEFBs) enable researchers to visualize and quantify cellular processes in live cells. Induced pluripotent stem cells (iPSCs) can be genetically engineered to express GEFBs via integration into the Adeno-Associated Virus Integration Site 1 (AAVS1) safe harbor locus. This can be achieved using CRISPR/Cas ribonucleoprotein targeting to cause a double-strand break at the AAVS1 locus, which subsequently undergoes homology-directed repair (HDR) in the presence of a donor plasmid containing the GEFB sequence. We describe an optimized protocol for CRISPR/Cas-mediated knock-in of GEFBs into the AAVS1 locus of human iPSCs that allows puromycin selection and which exhibits negligible off-target editing. The resulting iPSC lines can be differentiated into cells of different lineages while retaining expression of the GEFB, enabling live-cell interrogation of cell pathway activities across a diversity of disease models.
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Affiliation(s)
- David Stellon
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia.
| | | | - Jana Talbot
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia
| | - Sueanne Chear
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia
| | | | - Alice Pébay
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC, Australia.,Department of Surgery, Royal Melbourne Hospital, University of Melbourne, Parkville, VIC, Australia
| | - James C Vickers
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia
| | - Anna E King
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia
| | - Alex W Hewitt
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Anthony L Cook
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia.
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16
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Bearham J, Krutrök N, Lindberg B, Woodall M, Astrand A, Taylor JD, Biggart M, Vasiljevs S, Tarran R, Baines DL. A modified fluorescent sensor for reporting glucose concentration in the airway lumen. PLoS One 2021; 16:e0254248. [PMID: 34242292 PMCID: PMC8270177 DOI: 10.1371/journal.pone.0254248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/23/2021] [Indexed: 11/19/2022] Open
Abstract
We have modified the periplasmic Escherichia coli glucose/galactose binding protein (GBP) and labelled with environmentally sensitive fluorophores to further explore its potential as a sensor for the evaluation of glucose concentration in airway surface liquid (ASL). We identified E149C/A213R GBP labelled with N,N'-Dimethyl-N-(iodoacetyl)-N'-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)ethylenediamine (IANBD, emission wavelength maximum 536nm) with a Kd for D-glucose of 1.02mM and a fluorescence dynamic range of 5.8. This sensor was specific for D-glucose and exhibited fluorescence stability in experiments for several hours. The use of E149C/A213R GBP-IANBD in the ASL of airway cells grown at air-liquid-interface (ALI) detected an increase in glucose concentration 10 minutes after raising basolateral glucose from 5 to 15mM. This sensor also reported a greater change in ASL glucose concentration in response to increased basolateral glucose in H441 airway cells compared to human bronchial epithelial cells (HBEC) and there was less variability with HBEC data than that of H441 indicating that HBEC more effectively regulate glucose movement into the ASL. The sensor detected glucose in bronchoalveolar lavage fluid (BALf) from diabetic db/db mice but not normoglycaemic wildtype mice, indicating limited sensitivity of the sensor at glucose concentrations <50μM. Using nasal inhalation of the sensor and spectral unmixing to generate images, E149C/A213R GBP-IANBD fluorescence was detected in luminal regions of cryosections of the murine distal lung that was greater in db/db than wildtype mice. In conclusion, this sensor provides a useful tool for further development to measure luminal glucose concentration in models of lung/airway to explore how this may change in disease.
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Affiliation(s)
- Jade Bearham
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Nina Krutrök
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Botilda Lindberg
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Maximillian Woodall
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Annika Astrand
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - John D. Taylor
- Research and Early Development, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Matthew Biggart
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Stanislavs Vasiljevs
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Robert Tarran
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
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17
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Orlando M, Dvorzhak A, Bruentgens F, Maglione M, Rost BR, Sigrist SJ, Breustedt J, Schmitz D. Recruitment of release sites underlies chemical presynaptic potentiation at hippocampal mossy fiber boutons. PLoS Biol 2021; 19:e3001149. [PMID: 34153028 PMCID: PMC8216508 DOI: 10.1371/journal.pbio.3001149] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/17/2021] [Indexed: 01/14/2023] Open
Abstract
Synaptic plasticity is a cellular model for learning and memory. However, the expression mechanisms underlying presynaptic forms of plasticity are not well understood. Here, we investigate functional and structural correlates of presynaptic potentiation at large hippocampal mossy fiber boutons induced by the adenylyl cyclase activator forskolin. We performed 2-photon imaging of the genetically encoded glutamate sensor iGluu that revealed an increase in the surface area used for glutamate release at potentiated terminals. Time-gated stimulated emission depletion microscopy revealed no change in the coupling distance between P/Q-type calcium channels and release sites mapped by Munc13-1 cluster position. Finally, by high-pressure freezing and transmission electron microscopy analysis, we found a fast remodeling of synaptic ultrastructure at potentiated boutons: Synaptic vesicles dispersed in the terminal and accumulated at the active zones, while active zone density and synaptic complexity increased. We suggest that these rapid and early structural rearrangements might enable long-term increase in synaptic strength.
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Affiliation(s)
- Marta Orlando
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Berlin, Germany
| | - Anton Dvorzhak
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Berlin, Germany
| | - Felicitas Bruentgens
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Berlin, Germany
| | - Marta Maglione
- NeuroCure Cluster of Excellence, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Benjamin R. Rost
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Stephan J. Sigrist
- NeuroCure Cluster of Excellence, Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
- German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Jörg Breustedt
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Berlin, Germany
| | - Dietmar Schmitz
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Berlin, Germany
- German Center for Neurodegenerative Diseases, Berlin, Germany
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
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18
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Choi BJ, Chen YCD, Desplan C. Building a circuit through correlated spontaneous neuronal activity in the developing vertebrate and invertebrate visual systems. Genes Dev 2021; 35:677-691. [PMID: 33888564 PMCID: PMC8091978 DOI: 10.1101/gad.348241.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
During the development of the vertebrate nervous systems, genetic programs assemble an immature circuit that is subsequently refined by neuronal activity evoked by external stimuli. However, prior to sensory experience, the intrinsic property of the developing nervous system also triggers correlated network-level neuronal activity, with retinal waves in the developing vertebrate retina being the best documented example. Spontaneous activity has also been found in the visual system of Drosophila Here, we compare the spontaneous activity of the developing visual system between mammalian and Drosophila and suggest that Drosophila is an emerging model for mechanistic and functional studies of correlated spontaneous activity.
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Affiliation(s)
- Ben Jiwon Choi
- Department of Biology, New York University, New York, New York 10003, USA
| | | | - Claude Desplan
- Department of Biology, New York University, New York, New York 10003, USA
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19
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Brymer KJ, Barnes JR, Parsons MP. Entering a new era of quantifying glutamate clearance in health and disease. J Neurosci Res 2021; 99:1598-1617. [PMID: 33618436 DOI: 10.1002/jnr.24810] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/22/2021] [Accepted: 02/01/2021] [Indexed: 12/21/2022]
Abstract
Glutamate transporter proteins, expressed on both neurons and glia, serve as the main gatekeepers that dictate the spatial and temporal actions of extracellular glutamate. Glutamate is essential to the function of the healthy brain yet paradoxically contributes to the toxicity associated with many neurodegenerative diseases. Rapid transporter-mediated glutamate uptake, primarily occurring at astrocytic processes, tightens the efficiency of excitatory network activity and prevents toxic glutamate build-up in the extracellular space. Glutamate transporter dysfunction is thought to underlie myriad central nervous system (CNS) diseases including Alzheimer and Huntington disease. Over the past few decades, techniques such as biochemical uptake assays and electrophysiological recordings of transporter currents from individual astrocytes have revealed the remarkable ability of the CNS to efficiently clear extracellular glutamate. In more recent years, the rapidly evolving glutamate-sensing "sniffers" now allow researchers to visualize real-time glutamate transients on a millisecond time scale with single synapse spatial resolution in defined cell populations. As we transition to an increased reliance on optical-based methods of glutamate visualization and quantification, it is of utmost importance to understand not only the advantages that glutamate biosensors bring to the table but also the associated caveats and their implications for data interpretation. In this review, we summarize the strengths and limitations of the commonly used methods to quantify glutamate uptake. We then discuss what these techniques, when viewed as a complementary whole, have told us about the brain's ability to regulate glutamate levels, in both health and in the context of neurodegenerative disease.
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Affiliation(s)
- Kyle J Brymer
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Jocelyn R Barnes
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Matthew P Parsons
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
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20
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Plotegher N, Filadi R, Pizzo P, Duchen MR. Excitotoxicity Revisited: Mitochondria on the Verge of a Nervous Breakdown. Trends Neurosci 2021; 44:342-351. [PMID: 33608137 DOI: 10.1016/j.tins.2021.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/03/2020] [Accepted: 01/08/2021] [Indexed: 12/30/2022]
Abstract
Excitotoxicity is likely to occur in pathological scenarios in which mitochondrial function is already compromised, shaping neuronal responses to glutamate. In fact, mitochondria sustain cell bioenergetics, tune intracellular Ca2+ dynamics, and regulate glutamate availability by using it as metabolic substrate. Here, we suggest the need to explore glutamate toxicity in the context of specific disease models in which it may occur, re-evaluating the impact of mitochondrial dysfunction on glutamate excitotoxicity. Our aim is to signpost new approaches, perhaps combining glutamate and pathways to rescue mitochondrial function, as therapeutic targets in neurological disorders.
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Affiliation(s)
| | - Riccardo Filadi
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Neuroscience Institute, National Research Council (CNR), Padua, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Neuroscience Institute, National Research Council (CNR), Padua, Italy
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, UK.
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21
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AMPA receptor nanoscale dynamic organization and synaptic plasticities. Curr Opin Neurobiol 2020; 63:137-145. [DOI: 10.1016/j.conb.2020.04.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/28/2020] [Accepted: 04/13/2020] [Indexed: 12/13/2022]
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22
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Perez-Alvarez A, Fearey BC, O'Toole RJ, Yang W, Arganda-Carreras I, Lamothe-Molina PJ, Moeyaert B, Mohr MA, Panzera LC, Schulze C, Schreiter ER, Wiegert JS, Gee CE, Hoppa MB, Oertner TG. Freeze-frame imaging of synaptic activity using SynTagMA. Nat Commun 2020; 11:2464. [PMID: 32424147 PMCID: PMC7235013 DOI: 10.1038/s41467-020-16315-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/23/2020] [Indexed: 12/16/2022] Open
Abstract
Information within the brain travels from neuron to neuron across billions of synapses. At any given moment, only a small subset of neurons and synapses are active, but finding the active synapses in brain tissue has been a technical challenge. Here we introduce SynTagMA to tag active synapses in a user-defined time window. Upon 395-405 nm illumination, this genetically encoded marker of activity converts from green to red fluorescence if, and only if, it is bound to calcium. Targeted to presynaptic terminals, preSynTagMA allows discrimination between active and silent axons. Targeted to excitatory postsynapses, postSynTagMA creates a snapshot of synapses active just before photoconversion. To analyze large datasets, we show how to identify and track the fluorescence of thousands of individual synapses in an automated fashion. Together, these tools provide an efficient method for repeatedly mapping active neurons and synapses in cell culture, slice preparations, and in vivo during behavior.
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Affiliation(s)
- Alberto Perez-Alvarez
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Brenna C Fearey
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Ryan J O'Toole
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Wei Yang
- Research Group Synaptic Wiring and Information Processing, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Ignacio Arganda-Carreras
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
- Dept. of Computer Science and Artificial Intelligence, Basque Country University, San Sebastian, Spain
- Donostia International Physics Center (DIPC), San Sebastian, Spain
| | - Paul J Lamothe-Molina
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | | | - Manuel A Mohr
- HHMI, Janelia Farm Research Campus, Ashburn, VA, 20147, USA
| | - Lauren C Panzera
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Christian Schulze
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | | | - J Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Christine E Gee
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany
| | - Michael B Hoppa
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Thomas G Oertner
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, D-20251, Germany.
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Brock JA, Thomazeau A, Watanabe A, Li SSY, Sjöström PJ. A Practical Guide to Using CV Analysis for Determining the Locus of Synaptic Plasticity. Front Synaptic Neurosci 2020; 12:11. [PMID: 32292337 PMCID: PMC7118219 DOI: 10.3389/fnsyn.2020.00011] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/04/2020] [Indexed: 01/17/2023] Open
Abstract
Long-term synaptic plasticity is widely believed to underlie learning and memory in the brain. Whether plasticity is primarily expressed pre- or postsynaptically has been the subject of considerable debate for many decades. More recently, it is generally agreed that the locus of plasticity depends on a number of factors, such as developmental stage, induction protocol, and synapse type. Since presynaptic expression alters not just the gain but also the short-term dynamics of a synapse, whereas postsynaptic expression only modifies the gain, the locus has fundamental implications for circuits dynamics and computations in the brain. It therefore remains crucial for our understanding of neuronal circuits to know the locus of expression of long-term plasticity. One classical method for elucidating whether plasticity is pre- or postsynaptically expressed is based on analysis of the coefficient of variation (CV), which serves as a measure of noise levels of synaptic neurotransmission. Here, we provide a practical guide to using CV analysis for the purposes of exploring the locus of expression of long-term plasticity, primarily aimed at beginners in the field. We provide relatively simple intuitive background to an otherwise theoretically complex approach as well as simple mathematical derivations for key parametric relationships. We list important pitfalls of the method, accompanied by accessible computer simulations to better illustrate the problems (downloadable from GitHub), and we provide straightforward solutions for these issues.
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Affiliation(s)
- Jennifer A Brock
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Aurore Thomazeau
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Airi Watanabe
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Sally Si Ying Li
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - P Jesper Sjöström
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
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24
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O'Banion CP, Yasuda R. Fluorescent sensors for neuronal signaling. Curr Opin Neurobiol 2020; 63:31-41. [PMID: 32203701 DOI: 10.1016/j.conb.2020.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/30/2020] [Accepted: 02/13/2020] [Indexed: 12/14/2022]
Abstract
Dissecting neuronal structure and function in relation to behavior is an immense undertaking. Researchers require imaging tools to study neuronal activity and biochemical signaling in situ in order to study the roles of neuronal and biochemical activity in information processing. A large number of genetically encoded fluorescent biosensors have been reported in the literature over the past few years as there is a push to develop new technology in neuroscience. Here, we review the classes and characteristics of fluorescent biosensors and highlight some considerations that investigators should keep in mind when choosing their tool. In addition, we discuss recent advances in biosensor development.
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Affiliation(s)
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, United States.
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25
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Zhang XW, Hatamie A, Ewing AG. Simultaneous Quantification of Vesicle Size and Catecholamine Content by Resistive Pulses in Nanopores and Vesicle Impact Electrochemical Cytometry. J Am Chem Soc 2020; 142:4093-4097. [PMID: 32069039 PMCID: PMC7108759 DOI: 10.1021/jacs.9b13221] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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We have developed the means to simultaneously
measure the physical
size and count catecholamine molecules in individual nanometer transmitter
vesicles. This is done by combining resistive pulse (RP) measurements
in a nanopore pipet and vesicle impact electrochemical cytometry (VIEC)
at an electrode as the vesicle exits the nanopore. Analysis of freshly
isolated bovine adrenal vesicles shows that the size and internal
catecholamine concentration of vesicles varies with the occurrence
of a dense core inside the vesicles. These results might benefit the
understanding about the vesicles maturation, especially involving
the “sorting by retention” process and concentration
increase of intravesicular catecholamine. The methodology is applicable
to understanding soft nanoparticle collisions on electrodes, vesicles
in exocytosis and phagocytosis, intracellular vesicle transport, and
analysis of electroactive drugs in exosomes.
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Affiliation(s)
- Xin-Wei Zhang
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Amir Hatamie
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Andrew G Ewing
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
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