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Vezzoli E, Calì C, De Roo M, Ponzoni L, Sogne E, Gagnon N, Francolini M, Braida D, Sala M, Muller D, Falqui A, Magistretti PJ. Ultrastructural Evidence for a Role of Astrocytes and Glycogen-Derived Lactate in Learning-Dependent Synaptic Stabilization. Cereb Cortex 2021; 30:2114-2127. [PMID: 31807747 PMCID: PMC7174989 DOI: 10.1093/cercor/bhz226] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/17/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022] Open
Abstract
Long-term memory formation (LTM) is a process accompanied by energy-demanding structural changes at synapses and increased spine density. Concomitant increases in both spine volume and postsynaptic density (PSD) surface area have been suggested but never quantified in vivo by clear-cut experimental evidence. Using novel object recognition in mice as a learning task followed by 3D electron microscopy analysis, we demonstrate that LTM induced all aforementioned synaptic changes, together with an increase in the size of astrocytic glycogen granules, which are a source of lactate for neurons. The selective inhibition of glycogen metabolism in astrocytes impaired learning, affecting all the related synaptic changes. Intrahippocampal administration of l-lactate rescued the behavioral phenotype, along with spine density within 24 hours. Spine dynamics in hippocampal organotypic slices undergoing theta burst-induced long-term potentiation was similarly affected by inhibition of glycogen metabolism and rescued by l-lactate. These results suggest that learning primes astrocytic energy stores and signaling to sustain synaptic plasticity via l-lactate.
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Affiliation(s)
- E Vezzoli
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia.,Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy.,Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, 20133 Milano, Italy
| | - C Calì
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia
| | - M De Roo
- Department of Basic Neuroscience, University of Geneva Medical School, 1206 Geneva, Switzerland
| | - L Ponzoni
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, 20133 Milano, Italy
| | - E Sogne
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia
| | - N Gagnon
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia
| | - M Francolini
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, 20133 Milano, Italy
| | - D Braida
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, 20133 Milano, Italy
| | - M Sala
- CNR, Institute of Neuroscience, 20129 Milano, Italy
| | - D Muller
- Department of Basic Neuroscience, University of Geneva Medical School, 1206 Geneva, Switzerland
| | - A Falqui
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia
| | - P J Magistretti
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia
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Lossi L, Merighi A. The Use of ex Vivo Rodent Platforms in Neuroscience Translational Research With Attention to the 3Rs Philosophy. Front Vet Sci 2018; 5:164. [PMID: 30073174 PMCID: PMC6060265 DOI: 10.3389/fvets.2018.00164] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/29/2018] [Indexed: 01/08/2023] Open
Abstract
The principles of the 3Rs—Replacement, Reduction, and Refinement—are at the basis of most advanced national and supranational (EU) regulations on animal experimentation and welfare. In the perspective to reduce and refine the use of these animals in translational research, we here discuss the use of rodent acute and organotypically cultured central nervous system slices. We describe novel applications of these ex vivo platforms in medium-throughput screening of neuroactive molecules of potential pharmacological interest, with particular attention to more recent developments that permit to fully exploit the potential of direct genetic engineering of organotypic cultures using transfection techniques. We then describe the perspectives for expanding the use ex vivo platforms in neuroscience studies under the 3Rs philosophy using the following approaches: (1) Use of co-cultures of two brain regions physiologically connected to each other (source-target) to analyze axon regeneration and reconstruction of circuitries; (2) Microinjection or co-cultures of primary cells and/or cell lines releasing one or more neuroactive molecules to screen their physiological and/or pharmacological effects onto neuronal survival and slice circuitry. Microinjected or co-cultured cells are ideally made fluorescent after transfection with a plasmid construct encoding green or red fluorescent protein under the control of a general promoter such as hCMV; (3) Use of “sniffer” cells sensing the release of biologically active molecules from organotypic cultures by means of fluorescent probes. These cells can be prepared with activatable green fluorescent protein, a unique chromophore that remains in a “dark” state because its maturation is inhibited, and can be made fluorescent (de-quenched) if specific cellular enzymes, such as proteases or kinases, are activated.
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Affiliation(s)
- Laura Lossi
- Laboratory of Neurobiology, Department of Veterinary Sciences, University of Turin, Turin, Italy
| | - Adalberto Merighi
- Laboratory of Neurobiology, Department of Veterinary Sciences, University of Turin, Turin, Italy
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Fixman BB, Babcock IW, Minamide LS, Shaw AE, Oliveira da Silva MI, Runyan AM, Maloney MT, Field JJ, Bamburg JR. Modified Roller Tube Method for Precisely Localized and Repetitive Intermittent Imaging During Long-term Culture of Brain Slices in an Enclosed System. J Vis Exp 2017. [PMID: 29364208 DOI: 10.3791/56436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Cultured rodent brain slices are useful for studying the cellular and molecular behavior of neurons and glia in an environment that maintains many of their normal in vivo interactions. Slices obtained from a variety of transgenic mouse lines or use of viral vectors for expression of fluorescently tagged proteins or reporters in wild type brain slices allow for high-resolution imaging by fluorescence microscopy. Although several methods have been developed for imaging brain slices, combining slice culture with the ability to perform repetitive high-resolution imaging of specific cells in live slices over long time periods has posed problems. This is especially true when viral vectors are used for expression of exogenous proteins since this is best done in a closed system to protect users and prevent cross contamination. Simple modifications made to the roller tube brain slice culture method that allow for repetitive high-resolution imaging of slices over many weeks in an enclosed system are reported. Culturing slices on photoetched coverslips permits the use of fiducial marks to rapidly and precisely reposition the stage to image the identical field over time before and after different treatments. Examples are shown for the use of this method combined with specific neuronal staining and expression to observe changes in hippocampal slice architecture, viral-mediated neuronal expression of fluorescent proteins, and the development of cofilin pathology, which was previously observed in the hippocampus of Alzheimer's disease (AD) in response to slice treatment with oligomers of amyloid-β (Aβ) peptide.
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Affiliation(s)
- Benjamin B Fixman
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University
| | - Isaac W Babcock
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University
| | - Laurie S Minamide
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University
| | - Alisa E Shaw
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University
| | - Marina I Oliveira da Silva
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University; IBMC-Instituto de Biologia Molecular e Celular, i3S-Instituto de Investigaçãoe Inovação em Saúde, ICBAS, Universidade do Porto
| | - Avery M Runyan
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University
| | - Michael T Maloney
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University; Denali Therapeutics
| | - Jeffrey J Field
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology and Molecular, Cellular and Integrated Neuroscience Program, Colorado State University;
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