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Patel JC, Sherpa AD, Melani R, Witkovsky P, Wiseman MR, O'Neill B, Aoki C, Tritsch NX, Rice ME. GABA co-released from striatal dopamine axons dampens phasic dopamine release through autoregulatory GABA A receptors. Cell Rep 2024; 43:113834. [PMID: 38431842 DOI: 10.1016/j.celrep.2024.113834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/29/2023] [Accepted: 02/05/2024] [Indexed: 03/05/2024] Open
Abstract
Striatal dopamine axons co-release dopamine and gamma-aminobutyric acid (GABA), using GABA provided by uptake via GABA transporter-1 (GAT1). Functions of GABA co-release are poorly understood. We asked whether co-released GABA autoinhibits dopamine release via axonal GABA type A receptors (GABAARs), complementing established inhibition by dopamine acting at axonal D2 autoreceptors. We show that dopamine axons express α3-GABAAR subunits in mouse striatum. Enhanced dopamine release evoked by single-pulse optical stimulation in striatal slices with GABAAR antagonism confirms that an endogenous GABA tone limits dopamine release. Strikingly, an additional inhibitory component is seen when multiple pulses are used to mimic phasic axonal activity, revealing the role of GABAAR-mediated autoinhibition of dopamine release. This autoregulation is lost in conditional GAT1-knockout mice lacking GABA co-release. Given the faster kinetics of ionotropic GABAARs than G-protein-coupled D2 autoreceptors, our data reveal a mechanism whereby co-released GABA acts as a first responder to dampen phasic-to-tonic dopamine signaling.
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Affiliation(s)
- Jyoti C Patel
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA.
| | - Ang D Sherpa
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA; Center for Neural Science New York University, 4 Washington Place, New York, NY 10003, USA
| | - Riccardo Melani
- NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Paul Witkovsky
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Madeline R Wiseman
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Brian O'Neill
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Chiye Aoki
- NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA; Center for Neural Science New York University, 4 Washington Place, New York, NY 10003, USA
| | - Nicolas X Tritsch
- NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Margaret E Rice
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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Mukherjee S, Dubois C, Perez K, Varghese S, Birchall IE, Leckey M, Davydova N, McLean C, Nisbet RM, Roberts BR, Li QX, Masters CL, Streltsov VA. Quantitative proteomics of tau and Aβ in detergent fractions from Alzheimer's disease brains. J Neurochem 2023; 164:529-552. [PMID: 36271678 DOI: 10.1111/jnc.15713] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/16/2022] [Accepted: 10/17/2022] [Indexed: 11/27/2022]
Abstract
The two hallmarks of Alzheimer's disease (AD) are amyloid-β (Aβ) plaques and neurofibrillary tangles marked by phosphorylated tau. Increasing evidence suggests that aggregating Aβ drives tau accumulation, a process that involves synaptic degeneration leading to cognitive impairment. Conversely, there is a realization that non-fibrillar (oligomeric) forms of Aβ mediate toxicity in AD. Fibrillar (filamentous) aggregates of proteins across the spectrum of the primary and secondary tauopathies were the focus of recent structural studies with a filament structure-based nosologic classification, but less emphasis was given to non-filamentous co-aggregates of insoluble proteins in the fractions derived from post-mortem human brains. Here, we revisited sarkosyl-soluble and -insoluble extracts to characterize tau and Aβ species by quantitative targeted mass spectrometric proteomics, biochemical assays, and electron microscopy. AD brain sarkosyl-insoluble pellets were greatly enriched with Aβ42 at almost equimolar levels to N-terminal truncated microtubule-binding region (MTBR) isoforms of tau with multiple site-specific post-translational modifications (PTMs). MTBR R3 and R4 tau peptides were most abundant in the sarkosyl-insoluble materials with a 10-fold higher concentration than N-terminal tau peptides. This indicates that the major proportion of the enriched tau was the aggregation-prone N-terminal and proline-rich region (PRR) of truncated mixed 4R and 3R tau with more 4R than 3R isoforms. High concentration and occupancies of site-specific phosphorylation pT181 (~22%) and pT217 (~16%) (key biomarkers of AD) along with other PTMs in the PRR and MTBR indicated a regional susceptibility of PTMs in aggregated tau. Immunogold labelling revealed that tau may exist in globular non-filamentous form (N-terminal intact tau) co-localized with Aβ in the sarkosyl-insoluble pellets along with tau filaments (N-truncated MTBR tau). Our results suggest a model that Aβ and tau interact forming globular aggregates, from which filamentous tau and Aβ emerge. These characterizations contribute towards unravelling the sequence of events which lead to end-stage AD changes.
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Affiliation(s)
- Soumya Mukherjee
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Celine Dubois
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Keyla Perez
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Shiji Varghese
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Ian E Birchall
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Miranda Leckey
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Natalia Davydova
- National Deuteration Facility, Australian Nuclear Science and Technology Organization, Lucas Heights, New South Wales, Australia
| | - Catriona McLean
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia.,Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria, Australia
| | - Rebecca M Nisbet
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Blaine R Roberts
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Qiao-Xin Li
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Colin L Masters
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Victor A Streltsov
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
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Shibata S, Iseda T, Mitsuhashi T, Oka A, Shindo T, Moritoki N, Nagai T, Otsubo S, Inoue T, Sasaki E, Akazawa C, Takahashi T, Schalek R, Lichtman JW, Okano H. Large-Area Fluorescence and Electron Microscopic Correlative Imaging With Multibeam Scanning Electron Microscopy. Front Neural Circuits 2019; 13:29. [PMID: 31133819 PMCID: PMC6517476 DOI: 10.3389/fncir.2019.00029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 04/08/2019] [Indexed: 01/21/2023] Open
Abstract
Recent improvements in correlative light and electron microscopy (CLEM) technology have led to dramatic improvements in the ability to observe tissues and cells. Fluorescence labeling has been used to visualize the localization of molecules of interest through immunostaining or genetic modification strategies for the identification of the molecular signatures of biological specimens. Newer technologies such as tissue clearing have expanded the field of observation available for fluorescence labeling; however, the area of correlative observation available for electron microscopy (EM) remains restricted. In this study, we developed a large-area CLEM imaging procedure to show specific molecular localization in large-scale EM sections of mouse and marmoset brain. Target molecules were labeled with antibodies and sequentially visualized in cryostat sections using fluorescence and gold particles. Fluorescence images were obtained by light microscopy immediately after antibody staining. Immunostained sections were postfixed for EM, and silver-enhanced sections were dehydrated in a graded ethanol series and embedded in resin. Ultrathin sections for EM were prepared from fully polymerized resin blocks, collected on silicon wafers, and observed by multibeam scanning electron microscopy (SEM). Multibeam SEM has made rapid, large-area observation at high resolution possible, paving the way for the analysis of detailed structures using the CLEM approach. Here, we describe detailed methods for large-area CLEM in various tissues of both rodents and primates.
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Affiliation(s)
- Shinsuke Shibata
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan.,Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Taro Iseda
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan.,Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | | | - Atsushi Oka
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Tomoko Shindo
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan.,Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Nobuko Moritoki
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan
| | - Toshihiro Nagai
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan
| | - Shinya Otsubo
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Takashi Inoue
- Central Institute for Experimental Animals, Kawasaki, Japan
| | - Erika Sasaki
- Central Institute for Experimental Animals, Kawasaki, Japan
| | - Chihiro Akazawa
- Department of Biochemistry and Biophysics, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takao Takahashi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Richard Schalek
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Jeff W Lichtman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Hideyuki Okano
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan.,Department of Physiology, Keio University School of Medicine, Tokyo, Japan.,Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Wakō, Japan
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Ferguson S, Lucocq J. The invasive cell coat at the microsporidian Trachipleistophora hominis-host cell interface contains secreted hexokinases. Microbiologyopen 2018; 8:e00696. [PMID: 30051624 PMCID: PMC6460350 DOI: 10.1002/mbo3.696] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/22/2018] [Accepted: 06/25/2018] [Indexed: 02/04/2023] Open
Abstract
Microsporidia are obligate intracellular parasites causing significant disease in humans and economically important animals. In parallel to their extreme genetic reduction, Microsporidia have evolved novel mechanisms for exploiting host metabolism. A number of microsporidians confer secretion of otherwise cytosolic proteins by coding for signal peptides that direct entry into the endoplasmic reticulum. The human pathogen Trachipleistophora hominis encodes for four hexokinases, three of which have signal peptides at the N‐terminus. Here, we localized hexokinase 2 and hexokinase 3 through developmental stages of T. hominis using light and electron microscopy. Both proteins were concentrated in an extracellular coat previously termed the plaque matrix (PQM). The PQM (containing hexokinases) was morphologically dynamic, infiltrating the host cytoplasm predominantly during replicative stages. Throughout development the PQM interacted closely with endoplasmic reticulum that was demonstrated to be active in membrane protein biosynthesis and export. The impact of hexokinase on the host metabolism was probed using the fluorescent analog of glucose, 2‐NBDG, which displayed spatially restricted increases in signal intensity at the parasite/vacuole surface, coincident with hexokinase/PQM distribution. Gross metabolic aberrations, measured using metabolic profiling with the Seahorse XF Analyzer, were not detectable in mixed stage cocultures. Overall, these results highlight a role for the extended cell coat of T. hominis in host–parasite interactions, within which secreted hexokinases may work as part of a metabolic machine to increase glycolytic capacity or ATP generation close to the parasite surface.
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Affiliation(s)
- Sophie Ferguson
- Structural Cell Biology Group, School of Medicine, University of St Andrews, St Andrews, UK
| | - John Lucocq
- Structural Cell Biology Group, School of Medicine, University of St Andrews, St Andrews, UK
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Margus H, Padari K, Pooga M. Insights into cell entry and intracellular trafficking of peptide and protein drugs provided by electron microscopy. Adv Drug Deliv Rev 2013; 65:1031-8. [PMID: 23624037 DOI: 10.1016/j.addr.2013.04.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 03/22/2013] [Accepted: 04/09/2013] [Indexed: 01/06/2023]
Abstract
For widening the arsenal of protein and peptide therapeutics that act within cells, their cell-entry mechanisms, intracellular trafficking and distribution need to be characterized in detail. Immunofluorescence microscopy has been a prevalent tool for these studies. However, due to the limited resolution, it is often complemented with other methods. This article focuses on the perspectives of electron microscopy in tracking the intracellular delivery and trafficking of proteins, peptides and their carriers. This review introduces the electron microscopy techniques and labeling methods currently used for studying the cellular whereabouts of peptides and proteins with a focus on their intracellular trafficking. Since cell-penetrating peptides have widely been harnessed as carriers for proteins and peptides, and their usage is rapidly expanding, a particular emphasis has been placed on their applications and cell-entry mechanisms.
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Popenko VI, Kutter EM, Ackermann HW. Anna S. Tikhonenko: Electron microscopist extraordinary. Bacteriophage 2013; 3:e23646. [PMID: 23819103 PMCID: PMC3694054 DOI: 10.4161/bact.23646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 11/25/2022]
Abstract
Anna Sergeyevna Tikhonenko (1925–2010) is to be remembered for the excellency of her electron microscopical work, particularly with bacteriophages. She published 113 articles and one book, Ultrastructure of Bacterial Viruses (Izdadelstvo Nauka, Moscow 1968; Plenum Press, New York, 1972). It included 134 micrographs and a complete overview of the 316 phages then examined by electron microscopy. Most micrographs were of exceptional quality. This book, a rarity in those days of strict separation of Soviet and Western research, was the first bacteriophage atlas in the literature and presented a morphological classification of phages into five categories of family level, similar to a scheme presented in 1965 by D.E. Bradley (J Royal Microsc Soc 84:257–316). Her book remains one of the fundamentals of phage research.
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Affiliation(s)
- Vladimir I Popenko
- Engelhardt Institute of Molecular Biology; Russian Academy of Sciences; Moscow, Russia
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