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Xin W, Kaneko M, Roth RH, Zhang A, Nocera S, Ding JB, Stryker MP, Chan JR. Oligodendrocytes and myelin limit neuronal plasticity in visual cortex. Nature 2024; 633:856-863. [PMID: 39169185 PMCID: PMC11424474 DOI: 10.1038/s41586-024-07853-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 07/19/2024] [Indexed: 08/23/2024]
Abstract
Developmental myelination is a protracted process in the mammalian brain1. One theory for why oligodendrocytes mature so slowly posits that myelination may stabilize neuronal circuits and temper neuronal plasticity as animals age2-4. We tested this theory in the visual cortex, which has a well-defined critical period for experience-dependent neuronal plasticity5. During adolescence, visual experience modulated the rate of oligodendrocyte maturation in visual cortex. To determine whether oligodendrocyte maturation in turn regulates neuronal plasticity, we genetically blocked oligodendrocyte differentiation and myelination in adolescent mice. In adult mice lacking adolescent oligodendrogenesis, a brief period of monocular deprivation led to a significant decrease in visual cortex responses to the deprived eye, reminiscent of the plasticity normally restricted to adolescence. This enhanced functional plasticity was accompanied by a greater turnover of dendritic spines and coordinated reductions in spine size following deprivation. Furthermore, inhibitory synaptic transmission, which gates experience-dependent plasticity at the circuit level, was diminished in the absence of adolescent oligodendrogenesis. These results establish a critical role for oligodendrocytes in shaping the maturation and stabilization of cortical circuits and support the concept of developmental myelination acting as a functional brake on neuronal plasticity.
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Affiliation(s)
- Wendy Xin
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA.
| | - Megumi Kaneko
- Department of Physiology, Kavli Institute for Fundamental Neuroscience and Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Richard H Roth
- Departments of Neurosurgery and Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Albert Zhang
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Sonia Nocera
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Jun B Ding
- Departments of Neurosurgery and Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Michael P Stryker
- Department of Physiology, Kavli Institute for Fundamental Neuroscience and Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Jonah R Chan
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA.
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2
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Le L, Miyanishi K, Tanaka J, Majewska AK. Microglial Regulation of Sleep and Wakefulness. ADVANCES IN NEUROBIOLOGY 2024; 37:243-260. [PMID: 39207696 DOI: 10.1007/978-3-031-55529-9_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Sleep serves a multitude of roles in brain maturation and function. Although the neural networks involved in sleep regulation have been extensively characterized, it is increasingly recognized that neurons are not the sole conductor orchestrating the rhythmic cycle of sleep and wakefulness. In the central nervous system, microglia have emerged as an important player in sleep regulation. Within the last two decades, microglia have gained substantial attention for carrying out numerous nonimmune tasks that are crucial for brain development and function by co-opting similar mechanisms used in their conventional immune functions. Here, we highlight the importance of microglia in sleep regulation with recent findings reporting an arrhythmic sleep/wake cycle in the absence of microglia. Although the underlying mechanisms for such regulation are still being uncovered, it is likely that microglial contributions to the rhythmic control of the sleep/wake cycle come from their influence on synaptic strength and neuronal activity. We review the current literature to provide speculative signaling pathways and suggest key questions for future research. Advancing our knowledge of the mechanistic contribution of microglia to sleep regulation will not only further our insight into this critical biological process but also be instrumental in providing novel therapeutic strategies for sleep disorders.
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Affiliation(s)
- Linh Le
- Department of Neuroscience, Del Monte Institute of Neuroscience, Center for Visual Science, Neuroscience Graduate Program, University of Rochester, Rochester, NY, USA
| | - Kazuya Miyanishi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Japan.
| | - Ania K Majewska
- Department of Neuroscience, Del Monte Institute of Neuroscience, Center for Visual Science, Neuroscience Graduate Program, University of Rochester, Rochester, NY, USA.
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3
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Xin W, Kaneko M, Roth RH, Zhang A, Nocera S, Ding JB, Stryker MP, Chan JR. Adolescent oligodendrogenesis and myelination restrict experience-dependent neuronal plasticity in adult visual cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560231. [PMID: 37808666 PMCID: PMC10557765 DOI: 10.1101/2023.09.29.560231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
BACKGROUND Developmental myelination is a protracted process in the mammalian brain. One theory for why oligodendrocytes mature so slowly posits that myelination may stabilize neuronal circuits and temper neuronal plasticity as animals age. We tested this hypothesis in the visual cortex, which has a well-defined critical period for experience-dependent neuronal plasticity. OBJECTIVES/METHODS To prevent myelin progression, we conditionally deleted Myrf, a transcription factor necessary for oligodendrocyte maturation, from oligodendrocyte precursor cells (Myrf cKO) in adolescent mice. To induce experience-dependent plasticity, adult control and Myrf cKO mice were monocularly deprived by eyelid suture. Functional and structural neuronal plasticity in the visual cortex were assessed in vivo by intrinsic signal optical imaging and longitudinal two photon imaging of dendritic spines, respectively. RESULTS During adolescence, visual experience modulated the rate of oligodendrocyte maturation in visual cortex. Myrf deletion from oligodendrocyte precursors during adolescence led to inhibition of oligodendrocyte maturation and myelination that persisted into adulthood. Following monocular deprivation, visual cortex activity in response to visual stimulation of the deprived eye remained stable in adult control mice, as expected for post-critical period animals. By contrast, visual cortex responses to the deprived eye decreased significantly following monocular deprivation in adult Myrf cKO mice, reminiscent of the plasticity observed in adolescent mice. Furthermore, visual cortex neurons in adult Myrf cKO mice had fewer dendritic spines and a higher level of spine turnover. Finally, monocular deprivation induced spatially coordinated spine size decreases in adult Myrf cKO, but not control, mice. CONCLUSIONS These results demonstrate a critical role for oligodendrocytes in shaping the maturation and stabilization of cortical circuits and support the concept of myelin acting as a brake on neuronal plasticity during development.
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Affiliation(s)
- Wendy Xin
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco
| | - Megumi Kaneko
- Department of Physiology, Kavli Institute for Fundamental Neuroscience and Weill Institute for Neurosciences, University of California San Francisco
| | - Richard H Roth
- Departments of Neurosurgery and Neurology and Neurological Science, Stanford University
| | - Albert Zhang
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco
| | - Sonia Nocera
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco
| | - Jun B Ding
- Departments of Neurosurgery and Neurology and Neurological Science, Stanford University
| | - Michael P Stryker
- Department of Physiology, Kavli Institute for Fundamental Neuroscience and Weill Institute for Neurosciences, University of California San Francisco
| | - Jonah R Chan
- Department of Neurology, Weill Institute for Neurosciences, University of California San Francisco
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4
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Ashtari M, Cook P, Lipin M, Yu Y, Ying GS, Maguire A, Bennett J, Gee J, Zhang H. Dynamic structural remodeling of the human visual system prompted by bilateral retinal gene therapy. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 4:100089. [PMID: 37397812 PMCID: PMC10313860 DOI: 10.1016/j.crneur.2023.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/03/2023] [Accepted: 05/01/2023] [Indexed: 07/04/2023] Open
Abstract
The impact of changes in visual input on neuronal circuitry is complex and much of our knowledge on human brain plasticity of the visual systems comes from animal studies. Reinstating vision in a group of patients with low vision through retinal gene therapy creates a unique opportunity to dynamically study the underlying process responsible for brain plasticity. Historically, increases in the axonal myelination of the visual pathway has been the biomarker for brain plasticity. Here, we demonstrate that to reach the long-term effects of myelination increase, the human brain may undergo demyelination as part of a plasticity process. The maximum change in dendritic arborization of the primary visual cortex and the neurite density along the geniculostriate tracks occurred at three months (3MO) post intervention, in line with timing for the peak changes in postnatal synaptogenesis within the visual cortex reported in animal studies. The maximum change at 3MO for both the gray and white matter significantly correlated with patients' clinical responses to light stimulations called full field sensitivity threshold (FST). Our results shed a new light on the underlying process of brain plasticity by challenging the concept of increase myelination being the hallmark of brain plasticity and instead reinforcing the idea of signal speed optimization as a dynamic process for brain plasticity.
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Affiliation(s)
- Manzar Ashtari
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Philip Cook
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Mikhail Lipin
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Yinxi Yu
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Gui-Shuang Ying
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Albert Maguire
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - James Gee
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Hui Zhang
- Centre for Medical Image Computing, University College London, London, United Kingdom
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5
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Righes Marafiga J, Calcagnotto ME. Electrophysiology of Dendritic Spines: Information Processing, Dynamic Compartmentalization, and Synaptic Plasticity. ADVANCES IN NEUROBIOLOGY 2023; 34:103-141. [PMID: 37962795 DOI: 10.1007/978-3-031-36159-3_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
For many years, synaptic transmission was considered as information transfer between presynaptic neuron and postsynaptic cell. At the synaptic level, it was thought that dendritic arbors were only receiving and integrating all information flow sent along to the soma, while axons were primarily responsible for point-to-point information transfer. However, it is important to highlight that dendritic spines play a crucial role as postsynaptic components in central nervous system (CNS) synapses, not only integrating and filtering signals to the soma but also facilitating diverse connections with axons from many different sources. The majority of excitatory connections from presynaptic axonal terminals occurs on postsynaptic spines, although a subset of GABAergic synapses also targets spine heads. Several studies have shown the vast heterogeneous morphological, biochemical, and functional features of dendritic spines related to synaptic processing. In this chapter (adding to the relevant data on the biophysics of spines described in Chap. 1 of this book), we address the up-to-date functional dendritic characteristics assessed through electrophysiological approaches, including backpropagating action potentials (bAPs) and synaptic potentials mediated in dendritic and spine compartmentalization, as well as describing the temporal and spatial dynamics of glutamate receptors in the spines related to synaptic plasticity.
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Affiliation(s)
- Joseane Righes Marafiga
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Maria Elisa Calcagnotto
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
- Graduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
- Graduate Program in Psychiatry and Behavioral Science, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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6
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Fawcett JW, Fyhn M, Jendelova P, Kwok JCF, Ruzicka J, Sorg BA. The extracellular matrix and perineuronal nets in memory. Mol Psychiatry 2022; 27:3192-3203. [PMID: 35760878 PMCID: PMC9708575 DOI: 10.1038/s41380-022-01634-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/09/2022] [Accepted: 05/16/2022] [Indexed: 02/06/2023]
Abstract
All components of the CNS are surrounded by a diffuse extracellular matrix (ECM) containing chondroitin sulphate proteoglycans (CSPGs), heparan sulphate proteoglycans (HSPGs), hyaluronan, various glycoproteins including tenascins and thrombospondin, and many other molecules that are secreted into the ECM and bind to ECM components. In addition, some neurons, particularly inhibitory GABAergic parvalbumin-positive (PV) interneurons, are surrounded by a more condensed cartilage-like ECM called perineuronal nets (PNNs). PNNs surround the soma and proximal dendrites as net-like structures that surround the synapses. Attention has focused on the role of PNNs in the control of plasticity, but it is now clear that PNNs also play an important part in the modulation of memory. In this review we summarize the role of the ECM, particularly the PNNs, in the control of various types of memory and their participation in memory pathology. PNNs are now being considered as a target for the treatment of impaired memory. There are many potential treatment targets in PNNs, mainly through modulation of the sulphation, binding, and production of the various CSPGs that they contain or through digestion of their sulphated glycosaminoglycans.
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Affiliation(s)
- James W Fawcett
- John van Geest Centre for Brain Repair, Department Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK.
- Centre for Reconstructive Neuroscience, Institute for Experimental Medicine CAS, Videnska 1083, Prague 4, Prague, Czech Republic.
| | - Marianne Fyhn
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Pavla Jendelova
- Centre for Reconstructive Neuroscience, Institute for Experimental Medicine CAS, Videnska 1083, Prague 4, Prague, Czech Republic
| | - Jessica C F Kwok
- Centre for Reconstructive Neuroscience, Institute for Experimental Medicine CAS, Videnska 1083, Prague 4, Prague, Czech Republic
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Jiri Ruzicka
- Centre for Reconstructive Neuroscience, Institute for Experimental Medicine CAS, Videnska 1083, Prague 4, Prague, Czech Republic
| | - Barbara A Sorg
- Robert S. Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, USA
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Lin D, Wang Z, Chen W, Shen T, Qiu X, Wei K, Li J, Yang D, Wang P, Li X, Yan J, Tang Z. Regional Downregulation of Dopamine Receptor D1 in Bilateral Dorsal Lateral Geniculate Nucleus of Monocular Form-Deprived Amblyopia Models. Front Neurosci 2022; 16:861529. [PMID: 35757538 PMCID: PMC9213678 DOI: 10.3389/fnins.2022.861529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
Amblyopia is a common eye disease characterized by impaired best-corrected visual acuity. It starts in early childhood and leads to permanent vision reduction if left untreated. Even though many young patients with amblyopia are well treated in clinical practice, the underlying mechanism remains to be elucidated, which limits not only our understanding of this disease but also the therapeutic approach. To investigate the molecular mechanism of amblyopia, primate and rodent models of monocular-deprived amblyopia were created for mRNA screening and confirmation. We obtained 818 differentially expressed genes from the dorsal lateral geniculate nucleus (dLGN) of a primate model of amblyopia. After Gene Ontology and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses, the main enriched pathways were related to neural development. Interestingly, a particular neurotransmitter pathway, the dopaminergic pathway, was identified. The downregulation of dopamine receptor D1 (DRD1) was confirmed in both monkey and mouse samples. Furthermore, the immunofluorescence staining indicated that DRD1 expression was downregulated in both ventrolateral region of the contralateral dLGN and the dorsomedial region of the ipsilateral dLGN in the mouse model. The regions with downregulated expression of DRD1 were the downstream targets of the visual projection from the amblyopic eye. This study suggested that the downregulation of DRD1 in the LGN may be a cause for amblyopia. This may also be a reason for the failure of some clinical cases of levodopa combined with carbidopa applied to amblyopes.
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Affiliation(s)
- Dongyue Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Zhonghao Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Wei Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Tao Shen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Xuan Qiu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Kun Wei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Jiahui Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Dongsheng Yang
- Jinan Purui Eye Hospital, Children's Eye Disease and Ocular Motor Institute of Purui Jinan, Jinan, China
| | - Ping Wang
- Jinan Purui Eye Hospital, Children's Eye Disease and Ocular Motor Institute of Purui Jinan, Jinan, China
| | - Xuri Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Jianhua Yan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China
| | - Zhongshu Tang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou, China.,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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8
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Lupori L, Cornuti S, Mazziotti R, Borghi E, Ottaviano E, Cas MD, Sagona G, Pizzorusso T, Tognini P. The gut microbiota of environmentally enriched mice regulates visual cortical plasticity. Cell Rep 2022; 38:110212. [PMID: 35021093 DOI: 10.1016/j.celrep.2021.110212] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 11/08/2021] [Accepted: 12/14/2021] [Indexed: 12/24/2022] Open
Abstract
Exposing animals to an enriched environment (EE) has dramatic effects on brain structure, function, and plasticity. The poorly known "EE-derived signals'' mediating the EE effects are thought to be generated within the central nervous system. Here, we shift the focus to the body periphery, revealing that gut microbiota signals are crucial for EE-driven plasticity. Developmental analysis reveals striking differences in intestinal bacteria composition between EE and standard rearing (ST) mice, as well as enhanced levels of short-chain fatty acids (SCFA) in EE mice. Depleting the microbiota of EE mice with antibiotics strongly decreases SCFA and prevents activation of adult ocular dominance plasticity, spine dynamics, and microglia rearrangement. SCFA treatment in ST mice mimics EE induction of ocular dominance plasticity and microglial remodeling. Remarkably, transferring the microbiota of EE mice to ST recipients activates adult ocular dominance plasticity. Thus, experience-dependent changes in gut microbiota regulate brain plasticity.
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Affiliation(s)
| | - Sara Cornuti
- BIO@SNS Lab, Scuola Normale Superiore, 56126 Pisa, Italy
| | - Raffaele Mazziotti
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Elisa Borghi
- Department of Health Sciences, Università degli Studi di Milano, 20142 Milan, Italy
| | | | - Michele Dei Cas
- Department of Health Sciences, Università degli Studi di Milano, 20142 Milan, Italy
| | - Giulia Sagona
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Tommaso Pizzorusso
- BIO@SNS Lab, Scuola Normale Superiore, 56126 Pisa, Italy; Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA University of Florence, 50100 Florence, Italy; Institute of Neuroscience, National Research Council, 56124 Pisa, Italy
| | - Paola Tognini
- BIO@SNS Lab, Scuola Normale Superiore, 56126 Pisa, Italy; Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy.
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9
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Chen CC, Brumberg JC. Sensory Experience as a Regulator of Structural Plasticity in the Developing Whisker-to-Barrel System. Front Cell Neurosci 2022; 15:770453. [PMID: 35002626 PMCID: PMC8739903 DOI: 10.3389/fncel.2021.770453] [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: 09/03/2021] [Accepted: 11/22/2021] [Indexed: 12/28/2022] Open
Abstract
Cellular structures provide the physical foundation for the functionality of the nervous system, and their developmental trajectory can be influenced by the characteristics of the external environment that an organism interacts with. Historical and recent works have determined that sensory experiences, particularly during developmental critical periods, are crucial for information processing in the brain, which in turn profoundly influence neuronal and non-neuronal cortical structures that subsequently impact the animals' behavioral and cognitive outputs. In this review, we focus on how altering sensory experience influences normal/healthy development of the central nervous system, particularly focusing on the cerebral cortex using the rodent whisker-to-barrel system as an illustrative model. A better understanding of structural plasticity, encompassing multiple aspects such as neuronal, glial, and extra-cellular domains, provides a more integrative view allowing for a deeper appreciation of how all aspects of the brain work together as a whole.
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Affiliation(s)
- Chia-Chien Chen
- Department of Psychology, Queens College City University of New York, Flushing, NY, United States.,Department of Neuroscience, Duke Kunshan University, Suzhou, China
| | - Joshua C Brumberg
- Department of Psychology, Queens College City University of New York, Flushing, NY, United States.,The Biology (Neuroscience) and Psychology (Behavioral and Cognitive Neuroscience) PhD Programs, The Graduate Center, The City University of New York, New York, NY, United States
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10
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Jenks KR, Tsimring K, Ip JPK, Zepeda JC, Sur M. Heterosynaptic Plasticity and the Experience-Dependent Refinement of Developing Neuronal Circuits. Front Neural Circuits 2021; 15:803401. [PMID: 34949992 PMCID: PMC8689143 DOI: 10.3389/fncir.2021.803401] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/15/2021] [Indexed: 01/01/2023] Open
Abstract
Neurons remodel the structure and strength of their synapses during critical periods of development in order to optimize both perception and cognition. Many of these developmental synaptic changes are thought to occur through synapse-specific homosynaptic forms of experience-dependent plasticity. However, homosynaptic plasticity can also induce or contribute to the plasticity of neighboring synapses through heterosynaptic interactions. Decades of research in vitro have uncovered many of the molecular mechanisms of heterosynaptic plasticity that mediate local compensation for homosynaptic plasticity, facilitation of further bouts of plasticity in nearby synapses, and cooperative induction of plasticity by neighboring synapses acting in concert. These discoveries greatly benefited from new tools and technologies that permitted single synapse imaging and manipulation of structure, function, and protein dynamics in living neurons. With the recent advent and application of similar tools for in vivo research, it is now feasible to explore how heterosynaptic plasticity contribute to critical periods and the development of neuronal circuits. In this review, we will first define the forms heterosynaptic plasticity can take and describe our current understanding of their molecular mechanisms. Then, we will outline how heterosynaptic plasticity may lead to meaningful refinement of neuronal responses and observations that suggest such mechanisms are indeed at work in vivo. Finally, we will use a well-studied model of cortical plasticity—ocular dominance plasticity during a critical period of visual cortex development—to highlight the molecular overlap between heterosynaptic and developmental forms of plasticity, and suggest potential avenues of future research.
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Affiliation(s)
- Kyle R Jenks
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Katya Tsimring
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jacque Pak Kan Ip
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jose C Zepeda
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Mriganka Sur
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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11
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Aronitz EM, Kamermans BA, Duffy KR. Development of parvalbumin neurons and perineuronal nets in the visual cortex of normal and dark-exposed cats. J Comp Neurol 2021; 529:2827-2841. [PMID: 33576496 DOI: 10.1002/cne.25127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 11/06/2022]
Abstract
During development, the visual system maintains a high capacity for modification by expressing characteristics permissive for plasticity, enabling neural circuits to be refined by visual experience to achieve their mature form. This period is followed by the emergence of characteristics that stabilize the brain to consolidate for lifetime connections that were informed by experience. Attenuation of plasticity potential is thought to derive from an accumulation of plasticity-inhibiting characteristics that appear at ages beyond the peak of plasticity. Perineuronal nets (PNNs) are molecular aggregations that primarily surround fast-spiking inhibitory neurons called parvalbumin (PV) cells, which exhibit properties congruent with a plasticity inhibitor. In this study, we examined the development of PNNs and PV cells in the primary visual cortex of a highly visual mammal, and assessed the impact that 10 days of darkness had on both characteristics. Here, we show that labeling for PV expression emerges earlier and reaches adult levels sooner than PNNs. We also demonstrate that darkness, a condition known to enhance plasticity, significantly reduces the density of PNNs and the size of PV cell somata but does not alter the number of PV cells in the visual cortex. The darkness-induced reduction of PV cell size occurred irrespective of whether neurons were surrounded by a PNN, suggesting that PNNs have a restricted capacity to inhibit plasticity. Finally, we show that PV cells surrounded by a PNN were significantly larger than those without one, supporting the view that PNNs may mediate trophic support to the cells they surround.
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Affiliation(s)
- Elise M Aronitz
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Braden A Kamermans
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kevin R Duffy
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
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12
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Wong EL, Strohm A, Atlas J, Lamantia C, Majewska AK. Dynamics of microglia and dendritic spines in early adolescent cortex after developmental alcohol exposure. Dev Neurobiol 2021; 81:786-804. [PMID: 34228891 DOI: 10.1002/dneu.22843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 05/26/2021] [Accepted: 06/13/2021] [Indexed: 11/05/2022]
Abstract
Fetal alcohol spectrum disorder patients suffer from many cognitive disabilities. These include impaired auditory, visual, and tactile sensory information processing, making it more difficult for these patients to learn to navigate social scenarios. Rodent studies have shown that alcohol exposure during the brain growth spurt (BGS) can lead to acute neuronal apoptosis and an immunological response by microglia in the somatosensory cortex. Since microglia have critical physiological functions, including the support of excitatory synapse remodeling via interactions with dendritic spines, we sought to understand whether BGS alcohol exposure has long-term effects on microglial or dendritic spine dynamics. Using in vivo two-photon microscopy in 4-5 week old mice, we evaluated microglial functions such as process motility, the response to tissue injury, and the dynamics of physical interactions between microglial processes and dendritic spines. We also investigated potential differences in the morphology, density, or dynamics of dendritic spines in layer I/II primary sensory cortex of control and BGS alcohol exposed mice. We found that microglial process motility and contact with dendritic spines were not altered after BGS alcohol exposure. While the response of microglial processes toward tissue injury was not significantly altered by prior alcohol exposure, there was a trend suggesting that alcohol early in life may prime microglia to respond more quickly to secondary injury. Spine density, morphology, stability, and remodeling over time were not perturbed after BGS alcohol exposure. We demonstrate that after BGS alcohol exposure, the physiological functions of microglia and excitatory neurons remain intact in early adolescence.
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Affiliation(s)
- Elissa L Wong
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York, US.,Department of Environmental Medicine, University of Rochester Medical Center, New York, US
| | - Alexandra Strohm
- Department of Environmental Medicine, University of Rochester Medical Center, New York, US
| | - Jason Atlas
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York, US
| | - Cassandra Lamantia
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York, US
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, New York, US.,Center for Visual Science, University of Rochester Medical Center, Rochester, New York, US
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13
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Davidson AM, Mejía-Gómez H, Jacobowitz M, Mostany R. Dendritic Spine Density and Dynamics of Layer 5 Pyramidal Neurons of the Primary Motor Cortex Are Elevated With Aging. Cereb Cortex 2021; 30:767-777. [PMID: 31298696 DOI: 10.1093/cercor/bhz124] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/17/2019] [Accepted: 05/20/2019] [Indexed: 01/04/2023] Open
Abstract
It is well established that motor impairment often occurs alongside healthy aging, leading to problems with fine motor skills and coordination. Although previously thought to be caused by neuronal death accumulating across the lifespan, it is now believed that the source of this impairment instead stems from more subtle changes in neural connectivity. The dendritic spine is a prime target for exploration of this problem because it is the postsynaptic partner of most excitatory synapses received by the pyramidal neuron, a cortical cell that carries much of the information processing load in the cerebral cortex. We repeatedly imaged the same dendrites in young adult and aged mouse motor cortex over the course of 1 month to look for differences in the baseline state of the dendritic spine population. These experiments reveal increased dendritic spine density, without obvious changes in spine clustering, occurring at the aged dendrite. Additionally, aged dendrites exhibit elevated spine turnover and stabilization alongside decreased long-term spine survival. These results suggest that at baseline the aged motor cortex may exist in a perpetual state of relative instability and attempts at compensation. This phenotype of aging may provide clues for future targets of aging-related motor impairment remediation.
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Affiliation(s)
- A M Davidson
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA 70118, USA.,Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - H Mejía-Gómez
- Neuroscience Program, Brain Institute, Tulane University, New Orleans, LA 70118, USA.,Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - M Jacobowitz
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - R Mostany
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA 70112, USA.,Brain Institute, Tulane University, New Orleans, LA 70118, USA
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14
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Chen C, Fu H, He P, Yang P, Tu H. Extracellular Matrix Muscle Arm Development Defective Protein Cooperates with the One Immunoglobulin Domain Protein To Suppress Precocious Synaptic Remodeling. ACS Chem Neurosci 2021; 12:2045-2056. [PMID: 34019371 DOI: 10.1021/acschemneuro.1c00194] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Synaptic remodeling plays important roles in health and neural disorders. Although previous studies revealed that several transcriptional programs control synaptic remodeling in the nematode Caenorhabditis elegans, the molecular mechanisms of the dorsal D-type (DD) synaptic remodeling are poorly understood. Here we show that extracellular matrix molecule muscle arm development defective protein-4 (MADD-4) cooperates with the one immunoglobulin domain protein-1 (OIG-1) to defer precocious DD synaptic remodeling. Specifically, loss of MADD-4 exhibited the precocious DD synaptic remodeling. The long isoform MADD-4L is dynamically expressed while the short isoform MADD-4B is persistently expressed in DD neurons of L1 stage. In the unc-30 mutant lacking the Pitx-type homeodomain transcription factor UNC-30, the expression levels of both MADD-4B and -L isoforms were dramatically downregulated in DD neurons of the L1 stage. Our further data showed that MADD-4B and -L isoforms physically interact with OIG-1 and madd-4 acts in the oig-1 genetic pathway to modulate the DD synaptic remodeling. Our findings demonstrated that the extracellular matrix plays a novel role in synaptic plasticity.
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Affiliation(s)
- Chunhong Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Institute of Neuroscience, College of Biology, Hunan University, 410082 Changsha, Hunan, China
| | - Huiyuan Fu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Institute of Neuroscience, College of Biology, Hunan University, 410082 Changsha, Hunan, China
| | - Ping He
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Institute of Neuroscience, College of Biology, Hunan University, 410082 Changsha, Hunan, China
| | - Peng Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Institute of Neuroscience, College of Biology, Hunan University, 410082 Changsha, Hunan, China
| | - Haijun Tu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Institute of Neuroscience, College of Biology, Hunan University, 410082 Changsha, Hunan, China
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15
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Schneider CL, Majewska AK, Busza A, Williams ZR, Mahon BZ, Sahin B. Selective serotonin reuptake inhibitors for functional recovery after stroke: similarities with the critical period and the role of experience-dependent plasticity. J Neurol 2021; 268:1203-1209. [PMID: 31346698 PMCID: PMC6980899 DOI: 10.1007/s00415-019-09480-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/17/2019] [Accepted: 07/19/2019] [Indexed: 01/01/2023]
Abstract
There has been a growing interest in the potential for plasticity-inducing pharmacological interventions to enhance post-stroke recovery. One group of drugs that continues to garner a great deal of attention in this regard is a class of antidepressants called the selective serotonin reuptake inhibitors. Here we propose a model for the mechanism by which these drugs may enhance plasticity after ischemic brain injury. First, we review the research in animal models demonstrating how selective serotonin reuptake inhibitors reopen the critical period for ocular dominance plasticity in adulthood. We then compare this period of heightened plasticity to the cellular and biochemical milieu of perilesional tissue after an ischemic event in the adult brain. We argue that selective serotonin reuptake inhibitors administered acutely after an ischemic stroke alter excitatory-inhibitory balance in perilesional tissue and reinstate a type of plasticity reminiscent of the critical period in development. Finally, we discuss opportunities for future research in this area in both the preclinical and clinical realms.
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Affiliation(s)
- Colleen L Schneider
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, 14627, USA
- Medical Scientist Training Program, University of Rochester School of Medicine and Dentistry, Rochester, NY, 14642, USA
- Psychology Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, Rochester, NY, 14642, USA
| | - Ania Busza
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 681, Rochester, NY, 14642, USA
| | - Zoe R Williams
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 681, Rochester, NY, 14642, USA
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, 14642, USA
- Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Bradford Z Mahon
- Psychology Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
- Center for Visual Science, University of Rochester, Rochester, NY, 14642, USA
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 681, Rochester, NY, 14642, USA
- Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Bogachan Sahin
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 681, Rochester, NY, 14642, USA.
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16
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Heckman EL, Doe CQ. Establishment and Maintenance of Neural Circuit Architecture. J Neurosci 2021; 41:1119-1129. [PMID: 33568445 PMCID: PMC7888231 DOI: 10.1523/jneurosci.1143-20.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/29/2020] [Accepted: 12/09/2020] [Indexed: 02/03/2023] Open
Abstract
The ability to sense the world, process information, and navigate the environment depends on the assembly and continuous function of neural circuits in the brain. Within the past two decades, new technologies have rapidly advanced our understanding of how neural circuits are wired during development and how they are stably maintained, often for years. Electron microscopy reconstructions of model organism connectomes have provided a map of the stereotyped (and variable) connections in the brain; advanced light microscopy techniques have enabled direct observation of the cellular dynamics that underlie circuit construction and maintenance; transcriptomic and proteomic surveys of both developing and mature neurons have provided insights into the molecular and genetic programs governing circuit establishment and maintenance; and advanced genetic techniques have allowed for high-throughput discovery of wiring regulators. These tools have empowered scientists to rapidly generate and test hypotheses about how circuits establish and maintain connectivity. Thus, the set of principles governing circuit formation and maintenance have been expanded. These principles are discussed in this review.
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Affiliation(s)
- Emily L Heckman
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon 97403
| | - Chris Q Doe
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon 97403
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17
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Kasamatsu T, Imamura K. Ocular dominance plasticity: Molecular mechanisms revisited. J Comp Neurol 2020; 528:3039-3074. [PMID: 32737874 DOI: 10.1002/cne.25001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 07/10/2020] [Indexed: 12/14/2022]
Abstract
Ocular dominance plasticity (ODP) is a type of cortical plasticity operating in visual cortex of mammals that are endowed with binocular vision based on the competition-driven disparity. Earlier, a molecular mechanism was proposed that catecholamines play an important role in the maintenance of ODP in kittens. Having survived the initial test, the hypothesis was further advanced to identify noradrenaline (NA) as a key factor that regulates ODP in the immature cortex. Later, the ODP-promoting effect of NA is extended to the adult with age-related limitations. Following the enhanced NA availability, the chain events downstream lead to the β-adrenoreceptor-induced cAMP accumulation, which in turn activates the protein kinase A. Eventually, the protein kinase translocates to the cell nucleus to activate cAMP responsive element binding protein (CREB). CREB is a cellular transcription factor that controls the transcription of various genes, underpinning neuronal plasticity and long-term memory. In the advent of molecular genetics in that various types of new tools have become available with relative ease, ODP research has lightly adopted in the rodent model the original concepts and methodologies. Here, after briefly tracing the strategic maturation of our quest, the review moves to the later development of the field, with the emphasis placed around the following issues: (a) Are we testing ODP per se? (b) What does monocular deprivation deprive of the immature cortex? (c) The critical importance of binocular competition, (d) What is the adult plasticity? (e) Excitation-Inhibition balance in local circuits, and (f) Species differences in the animal models.
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Affiliation(s)
- Takuji Kasamatsu
- Smith-Kettlewell Eye Research Institute, San Francisco, California, USA
| | - Kazuyuki Imamura
- Department of Systems Life Engineering, Maebashi Institute of Technology, Maebashi-shi, Gunma, Japan
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18
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Nakanishi H, Ni J, Nonaka S, Hayashi Y. Microglial circadian clock regulation of microglial structural complexity, dendritic spine density and inflammatory response. Neurochem Int 2020; 142:104905. [PMID: 33217515 DOI: 10.1016/j.neuint.2020.104905] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 02/08/2023]
Abstract
Cortical microglia exhibit a ramified shape during sleep, while they have a hyper-ramified shape during wakefulness, which is characterized by their longer processes with increased branching points. The microglial molecular circadian clock regulates expressions of both cathepsin S (CatS) and P2Y12 receptors in the brain with a peak at zeitgeber time 14 (2 h after beginning of the dark phase). We postulated that these two microglia-specific molecules contribute to diurnal alterations of microglial shapes and neuronal activities in the cerebral cortex. During wakefulness, CatS secreted from cortical microglia may be involved in P2Y12 receptor-dependent process extension. Secreted CatS subsequently degrades the perineuronal nets, initiating the downscaling of both spine density and synaptic strength of cortical neurons toward the beginning of sleep. The downscaling of both spine density and synaptic strength of cortical neurons during sleep could improve signal-to-noise, which would benefit memory consolidation, or allow for new learning to occur during subsequent waking. Furthermore, disruption of CatS induces the sleep disturbance and impaired social interaction in mice. Moreover, the microglial clock system disruption may also play a role in the early pathogenesis of Alzheimer's disease. The reduced expression of BMAL1 in cortical microglia caused by oligomeric amyloid β may induce the increased presence of inflammatory phenotype through a reduction in RORα, which in turn reduced IκBα and enhanced NF-κB activation. These observations suggest that the microglial clock system disruption contribute to pathogeneses of sleep disturbance, impaired social interaction and cognitive impairment. Therefore, the growing understanding of the microglial circadian molecular clock might aid in the development of novel pharmacological interventions against both neuropsychiatric and neurodegenerative disorders.
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Affiliation(s)
- Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, 731-0153, Japan.
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy in the Ministry of Industry and Information Technology, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, 731-0153, Japan
| | - Yoshinori Hayashi
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
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19
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Baroncelli L, Lunghi C. Neuroplasticity of the visual cortex: in sickness and in health. Exp Neurol 2020; 335:113515. [PMID: 33132181 DOI: 10.1016/j.expneurol.2020.113515] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/14/2020] [Accepted: 10/21/2020] [Indexed: 01/18/2023]
Abstract
Brain plasticity refers to the ability of synaptic connections to adapt their function and structure in response to experience, including environmental changes, sensory deprivation and injuries. Plasticity is a distinctive, but not exclusive, property of the developing nervous system. This review introduces the concept of neuroplasticity and describes classic paradigms to illustrate cellular and molecular mechanisms underlying synapse modifiability. Then, we summarize a growing number of studies showing that the adult cerebral cortex retains a significant degree of plasticity highlighting how the identification of strategies to enhance the plastic potential of the adult brain could pave the way for the development of novel therapeutic approaches aimed at treating amblyopia and other neurodevelopmental disorders. Finally, we analyze how the visual system adjusts to neurodegenerative conditions leading to blindness and we discuss the crucial role of spared plasticity in the visual system for sight recovery.
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Affiliation(s)
- Laura Baroncelli
- Institute of Neuroscience, National Research Council (CNR), I-56124 Pisa, Italy; Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, I-56128 Pisa, Italy.
| | - Claudia Lunghi
- Laboratoire des systèmes perceptifs, Département d'études cognitives, École normale supérieure, PSL University, CNRS, 75005 Paris, France
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20
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Kawashita E, Ishihara K, Miyaji H, Tanishima Y, Kiriyama A, Matsuo O, Akiba S. α2-Antiplasmin as a potential regulator of the spatial memory process and age-related cognitive decline. Mol Brain 2020; 13:140. [PMID: 33059734 PMCID: PMC7566027 DOI: 10.1186/s13041-020-00677-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/25/2020] [Indexed: 11/13/2022] Open
Abstract
α2-Antiplasmin (α2AP), a principal physiological plasmin inhibitor, is mainly produced by the liver and kidneys, but it is also expressed in several parts of the brain, including the hippocampus and cerebral cortex. Our previous study demonstrated that α2AP knockout mice exhibit spatial memory impairment in comparison to wild-type mice, suggesting that α2AP is necessary for the fetal and/or neonatal development of the neural network for spatial memory. However, it is still unclear whether α2AP plays a role in the memory process. The present study demonstrated that adult hippocampal neurogenesis and remote spatial memory were enhanced by the injection of an anti-α2AP neutralizing antibody in WT mice, while the injection of α2AP reduced hippocampal neurogenesis and impaired remote spatial memory, suggesting that α2AP is a negative regulator in memory processing. The present study also found that the levels of α2AP in the brains of old mice were higher than those in young mice, and a negative correlation between the α2AP level and spatial working memory. In addition, aging-dependent brain oxidative stress and hippocampal inflammation were attenuated by α2AP deficiency. Thus, an age-related increase in α2AP might cause cognitive decline accompanied by brain oxidative stress and neuroinflammation. Taken together, our findings suggest that α2AP is a key regulator of the spatial memory process, and that it may represent a promising target to effectively regulate healthy brain aging.
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Affiliation(s)
- Eri Kawashita
- Department of Pathological Biochemistry, Kyoto Pharmaceutical University, 5, Nakauchi-cho Misasagi, Yamashina-ku, Kyoto, 607-8414, Japan.
| | - Keiichi Ishihara
- Department of Pathological Biochemistry, Kyoto Pharmaceutical University, 5, Nakauchi-cho Misasagi, Yamashina-ku, Kyoto, 607-8414, Japan
| | - Haruko Miyaji
- Department of Pathological Biochemistry, Kyoto Pharmaceutical University, 5, Nakauchi-cho Misasagi, Yamashina-ku, Kyoto, 607-8414, Japan
| | - Yu Tanishima
- Department of Pathological Biochemistry, Kyoto Pharmaceutical University, 5, Nakauchi-cho Misasagi, Yamashina-ku, Kyoto, 607-8414, Japan
| | - Akiko Kiriyama
- Department of Pharmacokinetics, Faculty of Pharmaceutical Science, Doshisha Women's College of Liberal Arts, Kodo, Kyotanabe-shi, Kyoto, 610-0395, Japan
| | - Osamu Matsuo
- Faculty of Medicine, Kindai University, 377-2 Ohnohigashi, Osakasayama, 589-8511, Japan
| | - Satoshi Akiba
- Department of Pathological Biochemistry, Kyoto Pharmaceutical University, 5, Nakauchi-cho Misasagi, Yamashina-ku, Kyoto, 607-8414, Japan
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21
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Napoli D, Lupori L, Mazziotti R, Sagona G, Bagnoli S, Samad M, Sacramento EK, Kirkpartick J, Putignano E, Chen S, Terzibasi Tozzini E, Tognini P, Baldi P, Kwok JC, Cellerino A, Pizzorusso T. MiR-29 coordinates age-dependent plasticity brakes in the adult visual cortex. EMBO Rep 2020; 21:e50431. [PMID: 33026181 DOI: 10.15252/embr.202050431] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 12/15/2022] Open
Abstract
Visual cortical circuits show profound plasticity during early life and are later stabilized by molecular "brakes" limiting excessive rewiring beyond a critical period. The mechanisms coordinating the expression of these factors during the transition from development to adulthood remain unknown. We found that miR-29a expression in the visual cortex dramatically increases with age, but it is not experience-dependent. Precocious high levels of miR-29a blocked ocular dominance plasticity and caused an early appearance of perineuronal nets. Conversely, inhibition of miR-29a in adult mice using LNA antagomirs activated ocular dominance plasticity, reduced perineuronal nets, and restored their juvenile chemical composition. Activated adult plasticity had the typical functional and proteomic signature of critical period plasticity. Transcriptomic and proteomic studies indicated that miR-29a manipulation regulates the expression of plasticity brakes in specific cortical circuits. These data indicate that miR-29a is a regulator of the plasticity brakes promoting age-dependent stabilization of visual cortical connections.
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Affiliation(s)
- Debora Napoli
- BIO@SNS Lab, Scuola Normale Superiore, Pisa, Italy.,Institute of Neuroscience, National Research Council, Pisa, Italy
| | | | - Raffaele Mazziotti
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA University of Florence, Florence, Italy
| | - Giulia Sagona
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA University of Florence, Florence, Italy.,Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.,Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Pisa, Italy
| | - Sara Bagnoli
- BIO@SNS Lab, Scuola Normale Superiore, Pisa, Italy
| | - Muntaha Samad
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, CA, USA
| | | | - Joanna Kirkpartick
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Elena Putignano
- Institute of Neuroscience, National Research Council, Pisa, Italy
| | - Siwei Chen
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, CA, USA
| | | | - Paola Tognini
- BIO@SNS Lab, Scuola Normale Superiore, Pisa, Italy.,Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Pierre Baldi
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, CA, USA
| | - Jessica Cf Kwok
- School of Biomedical Sciences, University of Leeds, Leeds, UK.,Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
| | - Alessandro Cellerino
- BIO@SNS Lab, Scuola Normale Superiore, Pisa, Italy.,Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Tommaso Pizzorusso
- BIO@SNS Lab, Scuola Normale Superiore, Pisa, Italy.,Institute of Neuroscience, National Research Council, Pisa, Italy.,Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA University of Florence, Florence, Italy
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22
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Zhang Y, Fu T, Han S, Ding Y, Wang J, Zheng J, Li J. Monocular Deprivation Affects Visual Cortex Plasticity Through cPKCγ-Modulated GluR1 Phosphorylation in Mice. Invest Ophthalmol Vis Sci 2020; 61:44. [PMID: 32343785 PMCID: PMC7401946 DOI: 10.1167/iovs.61.4.44] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose To determine how visual cortex plasticity changes after monocular deprivation (MD) in mice and whether conventional protein kinase C gamma (cPKCγ) plays a role in visual cortex plasticity. Methods cPKCγ membrane translocation levels were quantified by using immunoblotting to explore the effects of MD on cPKCγ activation. Electrophysiology was used to record field excitatory postsynaptic potential (fEPSP) amplitude with the goal of observing changes in visual cortex plasticity after MD. Immunoblotting was also used to determine the phosphorylation levels of GluR1 at Ser831. Light transmission was analyzed using electroretinography to examine the effects of MD and cPKCγ on mouse retinal function. Results Membrane translocation levels of cPKCγ significantly increased in the contralateral visual cortex of MD mice compared to wild-type (WT) mice (P < 0.001). In the contralateral visual cortex, long-term potentiation (LTP) and the phosphorylation levels of GluR1 at Ser 831 were increased in cPKCγ+/+ mice after MD. Interestingly, these levels could be downregulated by cPKCγ knockout compared to cPKCγ+/++MD mice (P < 0.001). Compared to the right eyes of WT mice, the amplitudes of a-waves and b-waves declined in deprived right eyes of mice after MD (P < 0.001). There were no significant differences when comparing cPKCγ+/+ and cPKCγ−/− mice with MD. Conclusions cPKCγ participates in the plasticity of the visual cortex after MD, which is characterized by increased LTP in the contralateral visual cortex, which may be a result of cPKCγ-mediated phosphorylation of GluR1 at Ser 831.
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23
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Frantz MG, Crouse EC, Sokhadze G, Ikrar T, Stephany CÉ, Nguyen C, Xu X, McGee AW. Layer 4 Gates Plasticity in Visual Cortex Independent of a Canonical Microcircuit. Curr Biol 2020; 30:2962-2973.e5. [PMID: 32589913 PMCID: PMC7919382 DOI: 10.1016/j.cub.2020.05.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/23/2020] [Accepted: 05/20/2020] [Indexed: 01/09/2023]
Abstract
Disrupting binocular vision during a developmental critical period can yield enduring changes to ocular dominance (OD) in primary visual cortex (V1). Here we investigated how this experience-dependent plasticity is coordinated within the laminar circuitry of V1 by deleting separately in each cortical layer (L) a gene required to close the critical period, nogo-66 receptor (ngr1). Deleting ngr1 in excitatory neurons in L4, but not in L2/3, L5, or L6, prevented closure of the critical period, and adult mice remained sensitive to brief monocular deprivation. Intracortical disinhibition, but not thalamocortical disinhibition, accompanied this OD plasticity. Both juvenile wild-type mice and adult mice lacking ngr1 in L4 displayed OD plasticity that advanced more rapidly L4 than L2/3 or L5. Interestingly, blocking OD plasticity in L2/3 with the drug AM-251 did not impair OD plasticity in L5. We propose that L4 restricts disinhibition and gates OD plasticity independent of a canonical cortical microcircuit.
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Affiliation(s)
- Michael G Frantz
- Developmental Neuroscience Program, Saban Research Institute, Children's Hospital Los Angeles, Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
| | - Emily C Crouse
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Guela Sokhadze
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Céleste-Élise Stephany
- Developmental Neuroscience Program, Saban Research Institute, Children's Hospital Los Angeles, Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
| | - Collins Nguyen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA.
| | - Aaron W McGee
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY 40202, USA; Developmental Neuroscience Program, Saban Research Institute, Children's Hospital Los Angeles, Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA.
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Nguyen PT, Dorman LC, Pan S, Vainchtein ID, Han RT, Nakao-Inoue H, Taloma SE, Barron JJ, Molofsky AB, Kheirbek MA, Molofsky AV. Microglial Remodeling of the Extracellular Matrix Promotes Synapse Plasticity. Cell 2020; 182:388-403.e15. [PMID: 32615087 DOI: 10.1016/j.cell.2020.05.050] [Citation(s) in RCA: 317] [Impact Index Per Article: 79.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 04/20/2020] [Accepted: 05/27/2020] [Indexed: 12/21/2022]
Abstract
Synapse remodeling is essential to encode experiences into neuronal circuits. Here, we define a molecular interaction between neurons and microglia that drives experience-dependent synapse remodeling in the hippocampus. We find that the cytokine interleukin-33 (IL-33) is expressed by adult hippocampal neurons in an experience-dependent manner and defines a neuronal subset primed for synaptic plasticity. Loss of neuronal IL-33 or the microglial IL-33 receptor leads to impaired spine plasticity, reduced newborn neuron integration, and diminished precision of remote fear memories. Memory precision and neuronal IL-33 are decreased in aged mice, and IL-33 gain of function mitigates age-related decreases in spine plasticity. We find that neuronal IL-33 instructs microglial engulfment of the extracellular matrix (ECM) and that its loss leads to impaired ECM engulfment and a concomitant accumulation of ECM proteins in contact with synapses. These data define a cellular mechanism through which microglia regulate experience-dependent synapse remodeling and promote memory consolidation.
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Affiliation(s)
- Phi T Nguyen
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Leah C Dorman
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Simon Pan
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Ilia D Vainchtein
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Rafael T Han
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Hiromi Nakao-Inoue
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Sunrae E Taloma
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Jerika J Barron
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Ari B Molofsky
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Mazen A Kheirbek
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA
| | - Anna V Molofsky
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA.
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25
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Murphy KM, Mancini SJ, Clayworth KV, Arbabi K, Beshara S. Experience-Dependent Changes in Myelin Basic Protein Expression in Adult Visual and Somatosensory Cortex. Front Cell Neurosci 2020; 14:56. [PMID: 32265660 PMCID: PMC7098538 DOI: 10.3389/fncel.2020.00056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/27/2020] [Indexed: 11/28/2022] Open
Abstract
An experience-driven increase in oligodendrocytes and myelin in the somatosensory cortex (S1) has emerged as a new marker of adult cortical plasticity. That finding contrasts with the view that myelin is a structural brake on plasticity, and that contributes to ending the critical period (CP) in the visual cortex (V1). Despite the evidence that myelin-derived signaling acts to end CP in V1, there is no information about myelin changes during adult plasticity in V1. To address this, we quantified the effect of three manipulations that drive adult plasticity (monocular deprivation (MD), fluoxetine treatment or the combination of MD and fluoxetine) on the expression of myelin basic protein (MBP) in adult rat V1. In tandem, we validated that environmental enrichment (EE) increased cortical myelin by measuring MBP in adult S1. For comparison with the MBP measurements, three plasticity markers were also quantified, the spine markers drebrin E and drebrin A, and a plasticity maintenance marker Ube3A. First, we confirmed that EE increased MBP in S1. Next, that expression of the plasticity markers was affected in S1 by EE and in V1 by the visual manipulations. Finally, we found that after adult MD, MBP increased in the non-deprived V1 hemisphere, but it decreased in the deprived hemisphere, and those changes were not influenced by fluoxetine. Together, the findings suggest that modulation of myelin expression in adult V1 may reflect the levels of visually driven activity rather than synaptic plasticity caused by adult plasticity.
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Affiliation(s)
- Kathryn M Murphy
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, ON, Canada.,Department of Psychology, Neuroscience & Behaviour, Faculty of Science, McMaster University, Hamilton, ON, Canada
| | - Steven J Mancini
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, ON, Canada
| | - Katherine V Clayworth
- Department of Psychology, Neuroscience & Behaviour, Faculty of Science, McMaster University, Hamilton, ON, Canada
| | - Keon Arbabi
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, ON, Canada
| | - Simon Beshara
- Division of Neurology, Department of Medicine, Queen's University, Kingston, ON, Canada
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26
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Murase S, Winkowski D, Liu J, Kanold PO, Quinlan EM. Homeostatic regulation of perisynaptic matrix metalloproteinase 9 (MMP9) activity in the amblyopic visual cortex. eLife 2019; 8:52503. [PMID: 31868167 PMCID: PMC6961978 DOI: 10.7554/elife.52503] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/19/2019] [Indexed: 01/07/2023] Open
Abstract
Dark exposure (DE) followed by light reintroduction (LRx) reactivates robust synaptic plasticity in adult mouse primary visual cortex (V1), which allows subsequent recovery from amblyopia. Previously we showed that perisynaptic proteolysis by MMP9 mediates the enhancement of plasticity by LRx in binocular adult mice (Murase et al., 2017). However, it was unknown if a visual system compromised by amblyopia could engage this pathway. Here we show that LRx to adult amblyopic mice induces perisynaptic MMP2/9 activity and extracellular matrix (ECM) degradation in deprived and non-deprived V1. Indeed, LRx restricted to the amblyopic eye is sufficient to induce robust MMP2/9 activity at thalamo-cortical synapses and ECM degradation in deprived V1. Two-photon live imaging demonstrates that the history of visual experience regulates MMP2/9 activity in V1, and that DE lowers the threshold for the proteinase activation. The homeostatic reduction of the MMP2/9 activation threshold by DE enables visual input from the amblyopic pathway to trigger robust perisynaptic proteolysis.
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Affiliation(s)
- Sachiko Murase
- Department of Biology, University of Maryland, College Park, United States.,Neuroscience Cognitive Sciences Program, University of Maryland, College Park, United States
| | - Dan Winkowski
- Department of Biology, University of Maryland, College Park, United States.,Neuroscience Cognitive Sciences Program, University of Maryland, College Park, United States
| | - Ji Liu
- Department of Biology, University of Maryland, College Park, United States.,Neuroscience Cognitive Sciences Program, University of Maryland, College Park, United States
| | - Patrick O Kanold
- Department of Biology, University of Maryland, College Park, United States.,Neuroscience Cognitive Sciences Program, University of Maryland, College Park, United States
| | - Elizabeth M Quinlan
- Department of Biology, University of Maryland, College Park, United States.,Neuroscience Cognitive Sciences Program, University of Maryland, College Park, United States
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27
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Lu H, Gallinaro JV, Rotter S. Network remodeling induced by transcranial brain stimulation: A computational model of tDCS-triggered cell assembly formation. Netw Neurosci 2019; 3:924-943. [PMID: 31637332 PMCID: PMC6777963 DOI: 10.1162/netn_a_00097] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 05/14/2019] [Indexed: 11/22/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) is a variant of noninvasive neuromodulation, which promises treatment for brain diseases like major depressive disorder. In experiments, long-lasting aftereffects were observed, suggesting that persistent plastic changes are induced. The mechanism underlying the emergence of lasting aftereffects, however, remains elusive. Here we propose a model, which assumes that tDCS triggers a homeostatic response of the network involving growth and decay of synapses. The cortical tissue exposed to tDCS is conceived as a recurrent network of excitatory and inhibitory neurons, with synapses subject to homeostatically regulated structural plasticity. We systematically tested various aspects of stimulation, including electrode size and montage, as well as stimulation intensity and duration. Our results suggest that transcranial stimulation perturbs the homeostatic equilibrium and leads to a pronounced growth response of the network. The stimulated population eventually eliminates excitatory synapses with the unstimulated population, and new synapses among stimulated neurons are grown to form a cell assembly. Strong focal stimulation tends to enhance the connectivity within new cell assemblies, and repetitive stimulation with well-chosen duty cycles can increase the impact of stimulation even further. One long-term goal of our work is to help in optimizing the use of tDCS in clinical applications. Noninvasive brain stimulation techniques like tDCS have the potential to directly interfere with neural activity, but may also trigger activity-dependent plasticity. We propose a model to study the mechanism of tDCS and persistent aftereffects that may be induced as a consequence of homeostatic structural plasticity. Based on the idea that tDCS perturbs the ongoing activity of neurons, our model predicts that the stimulation also triggers a rearrangement of synapses among stimulated and unstimulated neurons, eventually leading to network remodeling and cell assembly formation. Focal and strong stimulation leads to stronger cell assemblies, and so does repetitive stimulation with optimized stimulation protocols. This is the first original work studying possible long-lasting aftereffects of transcranial stimulation at the mesoscopic neuronal network level using a computational model.
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Affiliation(s)
- Han Lu
- Bernstein Center Freiburg and Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Júlia V Gallinaro
- Bernstein Center Freiburg and Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Stefan Rotter
- Bernstein Center Freiburg and Faculty of Biology, University of Freiburg, Freiburg, Germany
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28
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Yang Y, Lu J, Zuo Y. Changes of Synaptic Structures Associated with Learning, Memory and Diseases. BRAIN SCIENCE ADVANCES 2019. [DOI: 10.26599/bsa.2018.2018.9050012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Synaptic plasticity is widely believed to be the cellular basis of learning and memory. It is influenced by various factors including development, sensory experiences, and brain disorders. Long-term synaptic plasticity is accompanied by protein synthesis and trafficking, leading to structural changes of the synapse. In this review, we focus on the synaptic structural plasticity, which has mainly been studied with in vivo two-photon laser scanning microscopy. We also discuss how a special type of synapses, the multi-contact synapses (including those formed by multi-synaptic boutons and multi-synaptic spines), are associated with experience and learning.
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Affiliation(s)
- Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ju Lu
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA
| | - Yi Zuo
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA
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29
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Tran AP, Warren PM, Silver J. The Biology of Regeneration Failure and Success After Spinal Cord Injury. Physiol Rev 2018. [PMID: 29513146 DOI: 10.1152/physrev.00017.2017] [Citation(s) in RCA: 513] [Impact Index Per Article: 85.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Since no approved therapies to restore mobility and sensation following spinal cord injury (SCI) currently exist, a better understanding of the cellular and molecular mechanisms following SCI that compromise regeneration or neuroplasticity is needed to develop new strategies to promote axonal regrowth and restore function. Physical trauma to the spinal cord results in vascular disruption that, in turn, causes blood-spinal cord barrier rupture leading to hemorrhage and ischemia, followed by rampant local cell death. As subsequent edema and inflammation occur, neuronal and glial necrosis and apoptosis spread well beyond the initial site of impact, ultimately resolving into a cavity surrounded by glial/fibrotic scarring. The glial scar, which stabilizes the spread of secondary injury, also acts as a chronic, physical, and chemo-entrapping barrier that prevents axonal regeneration. Understanding the formative events in glial scarring helps guide strategies towards the development of potential therapies to enhance axon regeneration and functional recovery at both acute and chronic stages following SCI. This review will also discuss the perineuronal net and how chondroitin sulfate proteoglycans (CSPGs) deposited in both the glial scar and net impede axonal outgrowth at the level of the growth cone. We will end the review with a summary of current CSPG-targeting strategies that help to foster axonal regeneration, neuroplasticity/sprouting, and functional recovery following SCI.
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Affiliation(s)
- Amanda Phuong Tran
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Philippa Mary Warren
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
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30
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Abstract
The shift in ocular dominance (OD) of binocular neurons induced by monocular deprivation is the canonical model of synaptic plasticity confined to a postnatal critical period. Developmental constraints on this plasticity not only lend stability to the mature visual cortical circuitry but also impede the ability to recover from amblyopia beyond an early window. Advances with mouse models utilizing the power of molecular, genetic, and imaging tools are beginning to unravel the circuit, cellular, and molecular mechanisms controlling the onset and closure of the critical periods of plasticity in the primary visual cortex (V1). Emerging evidence suggests that mechanisms enabling plasticity in juveniles are not simply lost with age but rather that plasticity is actively constrained by the developmental up-regulation of molecular 'brakes'. Lifting these brakes enhances plasticity in the adult visual cortex, and can be harnessed to promote recovery from amblyopia. The reactivation of plasticity by experimental manipulations has revised the idea that robust OD plasticity is limited to early postnatal development. Here, we discuss recent insights into the neurobiology of the initiation and termination of critical periods and how our increasingly mechanistic understanding of these processes can be leveraged toward improved clinical treatment of adult amblyopia.
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31
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Omar MH, Kerrisk Campbell M, Xiao X, Zhong Q, Brunken WJ, Miner JH, Greer CA, Koleske AJ. CNS Neurons Deposit Laminin α5 to Stabilize Synapses. Cell Rep 2018; 21:1281-1292. [PMID: 29091766 PMCID: PMC5776391 DOI: 10.1016/j.celrep.2017.10.028] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/21/2017] [Accepted: 10/08/2017] [Indexed: 11/28/2022] Open
Abstract
Synapses in the developing brain are structurally dynamic but become stable by early adulthood. We demonstrate here that an α5-subunit-containing laminin stabilizes synapses during this developmental transition. Hippocampal neurons deposit laminin α5 at synapses during adolescence as connections stabilize. Disruption of laminin α5 in neurons causes dramatic fluctuations in dendritic spine head size that can be rescued by exogenous α5-containing laminin. Conditional deletion of laminin α5 in vivo increases dendritic spine size and leads to an age-dependent loss of synapses accompanied by behavioral defects. Remaining synapses have larger postsynaptic densities and enhanced neurotransmission. Finally, we provide evidence that laminin α5 acts through an integrin α3β1-Abl2 kinase-p190RhoGAP signaling cascade and partners with laminin β2 to regulate dendritic spine density and behavior. Together, our results identify laminin α5 as a stabilizer of dendritic spines and synapses in the brain and elucidate key cellular and molecular mechanisms by which it acts.
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Affiliation(s)
- Mitchell H Omar
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06510, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Meghan Kerrisk Campbell
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Xiao Xiao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Qiaonan Zhong
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06510, USA
| | - William J Brunken
- Department of Ophthalmology, Upstate Medical University, Syracuse, NY 13202, USA
| | - Jeffrey H Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Charles A Greer
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06510, USA; Department of Neuroscience, Yale University, New Haven, CT 06510, USA; Department of Neurosurgery, Yale University, New Haven, CT 06510, USA
| | - Anthony J Koleske
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06510, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA; Department of Neuroscience, Yale University, New Haven, CT 06510, USA.
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32
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Abstract
Circuit operations are determined jointly by the properties of the circuit elements and the properties of the connections among these elements. In the nervous system, neurons exhibit diverse morphologies and branching patterns, allowing rich compartmentalization within individual cells and complex synaptic interactions among groups of cells. In this review, we summarize work detailing how neuronal morphology impacts neural circuit function. In particular, we consider example neurons in the retina, cerebral cortex, and the stomatogastric ganglion of crustaceans. We also explore molecular coregulators of morphology and circuit function to begin bridging the gap between molecular and systems approaches. By identifying motifs in different systems, we move closer to understanding the structure-function relationships that are present in neural circuits.
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Affiliation(s)
| | - Stephen D Van Hooser
- Department of Biology, Brandeis University , Waltham, Massachusetts.,Volen Center for Complex Systems, Brandeis University , Waltham, Massachusetts.,Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University , Waltham, Massachusetts
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33
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Stradecki-Cohan HM, Cohan CH, Raval AP, Dave KR, Reginensi D, Gittens RA, Youbi M, Perez-Pinzon MA. Cognitive Deficits after Cerebral Ischemia and Underlying Dysfunctional Plasticity: Potential Targets for Recovery of Cognition. J Alzheimers Dis 2018; 60:S87-S105. [PMID: 28453486 DOI: 10.3233/jad-170057] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cerebral ischemia affects millions of people worldwide and survivors suffer from long-term functional and cognitive deficits. While stroke and cardiac arrest are typically considered when discussing ischemic brain injuries, there is much evidence that smaller ischemic insults underlie neurodegenerative diseases, including Alzheimer's disease. The "regenerative" capacity of the brain relies on several aspects of plasticity that are crucial for normal functioning; less affected brain areas may take over function previously performed by irreversibly damaged tissue. To harness the endogenous plasticity mechanisms of the brain to provide recovery of cognitive function, we must first understand how these mechanisms are altered after damage, such as cerebral ischemia. In this review, we discuss the long-term cognitive changes that result after cerebral ischemia and how ischemia alters several plasticity processes. We conclude with a discussion of how current and prospective therapies may restore brain plasticity and allow for recovery of cognitive function, which may be applicable to several disorders that have a disruption of cognitive processing, including traumatic brain injury and Alzheimer's disease.
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Affiliation(s)
- Holly M Stradecki-Cohan
- Department of Neurology Cerebral Vascular Disease Research Laboratories, Miami, FL, USA.,Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Charles H Cohan
- Department of Neurology Cerebral Vascular Disease Research Laboratories, Miami, FL, USA
| | - Ami P Raval
- Department of Neurology Cerebral Vascular Disease Research Laboratories, Miami, FL, USA
| | - Kunjan R Dave
- Department of Neurology Cerebral Vascular Disease Research Laboratories, Miami, FL, USA.,Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Diego Reginensi
- Centro de Neurociencias, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), City of Knowledge, Panama, Republic of Panama
| | - Rolando A Gittens
- Centro de Neurociencias, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), City of Knowledge, Panama, Republic of Panama
| | - Mehdi Youbi
- Department of Neurology Cerebral Vascular Disease Research Laboratories, Miami, FL, USA
| | - Miguel A Perez-Pinzon
- Department of Neurology Cerebral Vascular Disease Research Laboratories, Miami, FL, USA.,Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, USA
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34
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Proteolytic Remodeling of Perineuronal Nets: Effects on Synaptic Plasticity and Neuronal Population Dynamics. Neural Plast 2018. [PMID: 29531525 PMCID: PMC5817213 DOI: 10.1155/2018/5735789] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The perineuronal net (PNN) represents a lattice-like structure that is prominently expressed along the soma and proximal dendrites of parvalbumin- (PV-) positive interneurons in varied brain regions including the cortex and hippocampus. It is thus apposed to sites at which PV neurons receive synaptic input. Emerging evidence suggests that changes in PNN integrity may affect glutamatergic input to PV interneurons, a population that is critical for the expression of synchronous neuronal population discharges that occur with gamma oscillations and sharp-wave ripples. The present review is focused on the composition of PNNs, posttranslation modulation of PNN components by sulfation and proteolysis, PNN alterations in disease, and potential effects of PNN remodeling on neuronal plasticity at the single-cell and population level.
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35
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Abstract
During development, the environment exerts a profound influence on the wiring of brain circuits. Due to the limited resolution of studies in fixed tissue, this experience-dependent structural plasticity was once thought to be restricted to a specific developmental time window. The recent introduction of two-photon microscopy for in vivo imaging has opened the door to repeated monitoring of individual neurons and the study of structural plasticity mechanisms at a very fine scale. In this review, we focus on recent work showing that synaptic structural rearrangements are a key mechanism mediating neural circuit adaptation and behavioral plasticity in the adult brain. We examine this work in the context of classic studies in the visual systems of model organisms, which have laid much of the groundwork for our understanding of activity-dependent synaptic remodeling and its role in brain plasticity.
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Affiliation(s)
- Kalen P Berry
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Elly Nedivi
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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36
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Murase S, Lantz CL, Quinlan EM. Light reintroduction after dark exposure reactivates plasticity in adults via perisynaptic activation of MMP-9. eLife 2017; 6:27345. [PMID: 28875930 PMCID: PMC5630258 DOI: 10.7554/elife.27345] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/05/2017] [Indexed: 12/12/2022] Open
Abstract
The sensitivity of ocular dominance to regulation by monocular deprivation is the canonical model of plasticity confined to a critical period. However, we have previously shown that visual deprivation through dark exposure (DE) reactivates critical period plasticity in adults. Previous work assumed that the elimination of visual input was sufficient to enhance plasticity in the adult mouse visual cortex. In contrast, here we show that light reintroduction (LRx) after DE is responsible for the reactivation of plasticity. LRx triggers degradation of the ECM, which is blocked by pharmacological inhibition or genetic ablation of matrix metalloproteinase-9 (MMP-9). LRx induces an increase in MMP-9 activity that is perisynaptic and enriched at thalamo-cortical synapses. The reactivation of plasticity by LRx is absent in Mmp9−/− mice, and is rescued by hyaluronidase, an enzyme that degrades core ECM components. Thus, the LRx-induced increase in MMP-9 removes constraints on structural and functional plasticity in the mature cortex.
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Affiliation(s)
- Sachiko Murase
- Neuroscience and Cognitive Sciences Program, Department of Biology, University of Maryland, Maryland, United States
| | - Crystal L Lantz
- Neuroscience and Cognitive Sciences Program, Department of Biology, University of Maryland, Maryland, United States
| | - Elizabeth M Quinlan
- Neuroscience and Cognitive Sciences Program, Department of Biology, University of Maryland, Maryland, United States
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37
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Lynx1 Limits Dendritic Spine Turnover in the Adult Visual Cortex. J Neurosci 2017; 36:9472-8. [PMID: 27605620 DOI: 10.1523/jneurosci.0580-16.2016] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 07/04/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Dendritic spine turnover becomes limited in the adult cerebral cortex. Identification of specific aspects of spine dynamics that can be unmasked in adulthood and its regulatory molecular mechanisms could provide novel therapeutic targets for inducing plasticity at both the functional and structural levels for robust recovery from brain disorders and injuries in adults. Lynx1, an endogenous inhibitor of nicotinic acetylcholine receptors, was previously shown to increase its expression in adulthood and thus to limit functional ocular dominance plasticity in adult primary visual cortex (V1). However, the role of this "brake" on spine dynamics is not known. We examined the contribution of Lynx1 on dendritic spine turnover before and after monocular deprivation (MD) in adult V1 with chronic in vivo imaging using two-photon microscopy and determined the spine turnover rate of apical dendrites of layer 5 (L5) and L2/3 pyramidal neurons in adult V1 of Lynx1 knock-out (KO) mice. We found that the deletion of Lynx1 doubled the baseline spine turnover rate, suggesting that the spine dynamics in the adult cortex is actively limited by the presence of Lynx1. After MD, adult Lynx1-KO mice selectively exhibit higher rate of spine loss with no difference in gain rate in L5 neurons compared with control wild-type counterparts, revealing a key signature of spine dynamics associated with robust functional plasticity in adult V1. Overall, Lynx1 could be a promising therapeutic target to induce not only functional, but also structural plasticity at the level of spine dynamics in the adult brain. SIGNIFICANCE STATEMENT Dendritic spine turnover becomes limited in the adult cortex. In mouse visual cortex, a premier model of experience-dependent plasticity, we found that the deletion of Lynx1, a nicotinic "brake" for functional plasticity, doubled the baseline spine turnover in adulthood, suggesting that the spine dynamics in the adult cortex is actively limited by Lynx1. After visual deprivation, spine loss, but not gain rate, remains higher in adult Lynx1 knock-out mice than in control wild-type mice, revealing a key signature of spine dynamics associated with robust functional plasticity. Lynx1 would be a promising target to induce not only functional, but also structural plasticity at the level of spine dynamics in adulthood.
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38
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Miyata S, Kitagawa H. Formation and remodeling of the brain extracellular matrix in neural plasticity: Roles of chondroitin sulfate and hyaluronan. Biochim Biophys Acta Gen Subj 2017. [PMID: 28625420 DOI: 10.1016/j.bbagen.2017.06.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND The extracellular matrix (ECM) of the brain is rich in glycosaminoglycans such as chondroitin sulfate (CS) and hyaluronan. These glycosaminoglycans are organized into either diffuse or condensed ECM. Diffuse ECM is distributed throughout the brain and fills perisynaptic spaces, whereas condensed ECM selectively surrounds parvalbumin-expressing inhibitory neurons (PV cells) in mesh-like structures called perineuronal nets (PNNs). The brain ECM acts as a non-specific physical barrier that modulates neural plasticity and axon regeneration. SCOPE OF REVIEW Here, we review recent progress in understanding of the molecular basis of organization and remodeling of the brain ECM, and the involvement of several types of experience-dependent neural plasticity, with a particular focus on the mechanism that regulates PV cell function through specific interactions between CS chains and their binding partners. We also discuss how the barrier function of the brain ECM restricts dendritic spine dynamics and limits axon regeneration after injury. MAJOR CONCLUSIONS The brain ECM not only forms physical barriers that modulate neural plasticity and axon regeneration, but also forms molecular brakes that actively controls maturation of PV cells and synapse plasticity in which sulfation patterns of CS chains play a key role. Structural remodeling of the brain ECM modulates neural function during development and pathogenesis. GENERAL SIGNIFICANCE Genetic or enzymatic manipulation of the brain ECM may restore neural plasticity and enhance recovery from nerve injury. This article is part of a Special Issue entitled Neuro-glycoscience, edited by Kenji Kadomatsu and Hiroshi Kitagawa.
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Affiliation(s)
- Shinji Miyata
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Nagoya 464-8601, Japan
| | - Hiroshi Kitagawa
- Department of Biochemistry, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Kobe 658-8558, Japan.
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39
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Jeanneret V, Yepes M. Tissue-type plasminogen activator is a homeostatic regulator of synaptic function in the central nervous system. Neural Regen Res 2017; 12:362-365. [PMID: 28469640 PMCID: PMC5399703 DOI: 10.4103/1673-5374.202924] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Membrane depolarization induces the release of the serine proteinase tissue-type plasminogen activator (tPA) from the presynaptic terminal of cerebral cortical neurons. Once in the synaptic cleft this tPA promotes the exocytosis and subsequent endocytic retrieval of glutamate-containing synaptic vesicles, and regulates the postsynaptic response to the presynaptic release of glutamate. Indeed, tPA has a bidirectional effect on the composition of the postsynaptic density (PSD) that does not require plasmin generation or the presynaptic release of glutamate, but varies according to the baseline level of neuronal activity. Hence, in inactive neurons tPA induces phosphorylation and accumulation in the PSD of the Ca2+/calmodulin-dependent protein kinase IIα (pCaMKIIα), followed by pCaMKIIα-induced phosphorylation and synaptic recruitment of GluR1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. In contrast, in active neurons with increased levels of pCaMKIIα in the PSD tPA induces pCaMKIIα and pGluR1 dephosphorylation and their subsequent removal from the PSD. These effects require active synaptic N-methyl-D-aspartate (NMDA) receptors and cyclin-dependent kinase 5 (Cdk5)-induced phosphorylation of the protein phosphatase 1 (PP1) at T320. These data indicate that tPA is a homeostatic regulator of the postsynaptic response of cerebral cortical neurons to the presynaptic release of glutamate via bidirectional regulation of the pCaMKIIα /PP1 switch in the PSD.
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Affiliation(s)
- Valerie Jeanneret
- Department of Neurology & Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA
| | - Manuel Yepes
- Department of Neurology & Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA.,Department of Neurology, Veterans Affairs Medical Center, Atlanta, GA, USA.,Division of Neurosciences, Yerkes National Primate Research Center, Atlanta, GA, USA
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40
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Tong L, Xie Y, Yu H. The temporal-spatial dynamics of feature maps during monocular deprivation revealed by chronic imaging and self-organization model simulation. Neuroscience 2016; 339:571-586. [PMID: 27746342 DOI: 10.1016/j.neuroscience.2016.10.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 11/18/2022]
Abstract
Experiments on the adult visual cortex of cats, ferrets and monkeys have revealed organized spatial relationships between multiple feature maps which can also be reproduced by the Kohonen and elastic net self-organization models. However, attempts to apply these models to simulate the temporal kinetics of monocular deprivation (MD) during the critical period, and their effects on the spatial arrangement of feature maps, have led to conflicting results. In this study, we performed MD and chronic imaging in the ferret visual cortex during the critical period of ocular dominance (OD) plasticity. We also used the Kohonen model to simulate the effects of MD on OD and orientation map development. Both the experiments and simulations demonstrated two general parameter-insensitive findings. Specifically, our first finding demonstrated that the OD index shift resulting from MD, and its subsequent recovery during binocular vision (BV), were both nonlinear, with a significantly stronger shift occurring during the initial period. Meanwhile, spatial reorganization of feature maps led to globally unchanged but locally shifted map patterns. In detail, we found that the periodicity of OD and orientation maps remained unchanged during, and after, deprivation. Relationships between OD and orientation maps remained similar but were significantly weakened due to OD border shifts. These results indicate that orthogonal gradient relationships between maps may be preset and are only mildly modifiable during the critical period. The Kohonen model was able to reproduce these experimental results, hence its role is further extended to the description of cortical feature map dynamics during development.
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Affiliation(s)
- Lei Tong
- School of Life Sciences and the State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 2005 Songhu Road, Shanghai, China
| | - Yang Xie
- School of Life Sciences and the State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 2005 Songhu Road, Shanghai, China
| | - Hongbo Yu
- School of Life Sciences and the State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, 2005 Songhu Road, Shanghai, China.
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41
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Nicotinic regulation of experience-dependent plasticity in visual cortex. ACTA ACUST UNITED AC 2016; 110:29-36. [PMID: 27840212 DOI: 10.1016/j.jphysparis.2016.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 09/19/2016] [Accepted: 11/09/2016] [Indexed: 11/20/2022]
Abstract
While the cholinergic neuromodulatory system and muscarinic acetylcholine receptors (AChRs) have been appreciated as permissive factors for developmental critical period plasticity in visual cortex, it was unknown why plasticity becomes limited after the critical period even in the presence of massive cholinergic projections to visual cortex. In this review we highlighted the recent progresses that started to shed light on the role of the nicotinic cholinergic neuromodulatory signaling on limiting juvenile form of plasticity in the adult brain. We introduce the Lynx family of proteins and Lynx1 as its representative, as endogenous proteins structurally similar to α-bungarotoxin with the ability to bind and modulate nAChRs to effectively regulate functional and structural plasticity. Remarkably, Lynx family members are expressed in distinct subpopulations of GABAergic interneurons, placing them in unique positions to potentially regulate the convergence of GABAergic and nicotinic neuromodulatory systems to regulate plasticity. Continuing studies of the potentially differential roles of Lynx family of proteins may further our understanding of the fundamentals of molecular and cell type-specific mechanisms of plasticity that we may be able to harness through nicotinic cholinergic signaling.
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42
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The olfactory bulbectomized rat as a model of depression: The hippocampal pathway. Behav Brain Res 2016; 317:562-575. [PMID: 27633561 DOI: 10.1016/j.bbr.2016.09.029] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/05/2016] [Accepted: 09/11/2016] [Indexed: 01/07/2023]
Abstract
In rodents, the removal of the olfactory bulbs (OBs), i.e. olfactory bulbectomy (OBX), results in numerous alterations in neurotransmitter, endocrine and immune systems, as well as behavioral changes, similar to those observed in depressed patients. Because the behavioral deficits induced in OBX animals are reversed after repeated administration of antidepressants, this is a model often used to test the effectiveness of putative antidepressant agents. Recent evidence suggests that OBX results in the dysfunction of various cellular processes within the hippocampus, including decreases in dentate gyrus neurogenesis, disruption in long-term potentiation in CA1 and CA3 subregions and neuronal atrophy in the CA1 subregion, along with downstream markers, all of which are consistent with abnormal neuronal activity in the hippocampus of clinically depressed populations. Moreover, repeated administration of novel natural and synthetic antidepressant compounds can improve certain aspects of depression-like behavior and hippocampal function. In an effort to bring together the existing literature, this review will focus on the mechanisms by which proposed pharmaceuticals impact hippocampal-dependent processes and behavior.
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43
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Dyer AH, Vahdatpour C, Sanfeliu A, Tropea D. The role of Insulin-Like Growth Factor 1 (IGF-1) in brain development, maturation and neuroplasticity. Neuroscience 2016; 325:89-99. [DOI: 10.1016/j.neuroscience.2016.03.056] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/29/2016] [Accepted: 03/24/2016] [Indexed: 02/07/2023]
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Unbiased, High-Throughput Electron Microscopy Analysis of Experience-Dependent Synaptic Changes in the Neocortex. J Neurosci 2016; 35:16450-62. [PMID: 26674870 DOI: 10.1523/jneurosci.1573-15.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Neocortical circuits can be altered by sensory and motor experience, with experimental evidence supporting both anatomical and electrophysiological changes in synaptic properties. Previous studies have focused on changes in specific neurons or pathways-for example, the thalamocortical circuitry, layer 4-3 (L4-L3) synapses, or in the apical dendrites of L5 neurons- but a broad-scale analysis of experience-induced changes across the cortical column has been lacking. Without this comprehensive approach, a full understanding of how cortical circuits adapt during learning or altered sensory input will be impossible. Here we adapt an electron microscopy technique that selectively labels synapses, in combination with a machine-learning algorithm for semiautomated synapse detection, to perform an unbiased analysis of developmental and experience-dependent changes in synaptic properties across an entire cortical column in mice. Synapse density and length were compared across development and during whisker-evoked plasticity. Between postnatal days 14 and 18, synapse density significantly increases most in superficial layers, and synapse length increases in L3 and L5B. Removal of all but a single whisker row for 24 h led to an apparent increase in synapse density in L2 and a decrease in L6, and a significant increase in length in L3. Targeted electrophysiological analysis of changes in miniature EPSC and IPSC properties in L2 pyramidal neurons showed that mEPSC frequency nearly doubled in the whisker-spared column, a difference that was highly significant. Together, this analysis shows that data-intensive analysis of column-wide changes in synapse properties can generate specific and testable hypotheses about experience-dependent changes in cortical organization. SIGNIFICANCE STATEMENT Development and sensory experience can change synapse properties in the neocortex. Here we use a semiautomated analysis of electron microscopy images for an unbiased, column-wide analysis of synapse changes. This analysis reveals new loci for synaptic change that can be verified by targeted electrophysiological investigation. This method can be used as a platform for generating new hypotheses about synaptic changes across different brain areas and experimental conditions.
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Su J, Chen J, Lippold K, Monavarfeshani A, Carrillo GL, Jenkins R, Fox MA. Collagen-derived matricryptins promote inhibitory nerve terminal formation in the developing neocortex. J Cell Biol 2016; 212:721-36. [PMID: 26975851 PMCID: PMC4792079 DOI: 10.1083/jcb.201509085] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/11/2016] [Indexed: 12/31/2022] Open
Abstract
Inhibitory synapses comprise only ∼20% of the total synapses in the mammalian brain but play essential roles in controlling neuronal activity. In fact, perturbing inhibitory synapses is associated with complex brain disorders, such as schizophrenia and epilepsy. Although many types of inhibitory synapses exist, these disorders have been strongly linked to defects in inhibitory synapses formed by Parvalbumin-expressing interneurons. Here, we discovered a novel role for an unconventional collagen-collagen XIX-in the formation of Parvalbumin(+) inhibitory synapses. Loss of this collagen results not only in decreased inhibitory synapse number, but also in the acquisition of schizophrenia-related behaviors. Mechanistically, these studies reveal that a proteolytically released fragment of this collagen, termed a matricryptin, promotes the assembly of inhibitory nerve terminals through integrin receptors. Collectively, these studies not only identify roles for collagen-derived matricryptins in cortical circuit formation, but they also reveal a novel paracrine mechanism that regulates the assembly of these synapses.
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Affiliation(s)
- Jianmin Su
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016
| | - Jiang Chen
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016
| | - Kumiko Lippold
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016
| | - Aboozar Monavarfeshani
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016 Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | | | - Rachel Jenkins
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Michael A Fox
- Virginia Tech Carilion Research Institute, Roanoke, VA 24016 Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
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46
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Sipe GO, Lowery RL, Tremblay MÈ, Kelly EA, Lamantia CE, Majewska AK. Microglial P2Y12 is necessary for synaptic plasticity in mouse visual cortex. Nat Commun 2016; 7:10905. [PMID: 26948129 PMCID: PMC4786684 DOI: 10.1038/ncomms10905] [Citation(s) in RCA: 338] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/01/2016] [Indexed: 12/19/2022] Open
Abstract
Microglia are the resident immune cells of the brain. Increasingly, they are recognized as important mediators of normal neurophysiology, particularly during early development. Here we demonstrate that microglia are critical for ocular dominance plasticity. During the visual critical period, closure of one eye elicits changes in the structure and function of connections underlying binocular responses of neurons in the visual cortex. We find that microglia respond to monocular deprivation during the critical period, altering their morphology, motility and phagocytic behaviour as well as interactions with synapses. To explore the underlying mechanism, we focused on the P2Y12 purinergic receptor, which is selectively expressed in non-activated microglia and mediates process motility during early injury responses. We find that disrupting this receptor alters the microglial response to monocular deprivation and abrogates ocular dominance plasticity. These results suggest that microglia actively contribute to experience-dependent plasticity in the adolescent brain. Microglia play key roles during early neurodevelopment. Here the authors show that microglia are important mediators of ocular dominance plasticity (ODP). Microglia respond to monocular deprivation during the visual critical period, and disrupting microglial P2Y12 purinergic receptor abrogates ODP.
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Affiliation(s)
- G O Sipe
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA.,Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - R L Lowery
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA.,Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - M-È Tremblay
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - E A Kelly
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - C E Lamantia
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - A K Majewska
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA.,Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
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47
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Flores G, Morales-Medina JC, Diaz A. Neuronal and brain morphological changes in animal models of schizophrenia. Behav Brain Res 2016; 301:190-203. [DOI: 10.1016/j.bbr.2015.12.034] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 12/14/2022]
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48
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Jeanneret V, Yepes M. The Plasminogen Activation System Promotes Dendritic Spine Recovery and Improvement in Neurological Function After an Ischemic Stroke. Transl Stroke Res 2016. [PMID: 26846991 DOI: 10.1007/s12975-016-0454-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Advances in neurocritical care and interventional neuroradiology have led to a significant decrease in acute ischemic stroke (AIS) mortality. In contrast, due to the lack of an effective therapeutic strategy to promote neuronal recovery among AIS survivors, cerebral ischemia is still a leading cause of disability in the world. Ischemic stroke has a harmful impact on synaptic structure and function, and plasticity-mediated synaptic recovery is associated with neurological improvement following an AIS. Dendritic spines (DSs) are specialized dendritic protrusions that receive most of the excitatory input in the brain. The deleterious effect of cerebral ischemia on DSs morphology and function has been associated with impaired synaptic transmission and neurological deterioration. However, these changes are reversible if cerebral blood flow is restored on time, and this recovery has been associated with neurological improvement following an AIS. Tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) are two serine proteases that, besides catalyzing the conversion of plasminogen into plasmin in the intravascular and pericellular environment, respectively, are also efficient inductors of synaptic plasticity. Accordingly, recent evidence indicates that both, tPA and uPA, protect DSs from the metabolic stress associated with the ischemic injury, and promote their morphological and functional recovery during the recovery phase from an AIS. Here, we will review data indicating that plasticity-induced changes in DSs and the associated post-synaptic density play a pivotal role in the recovery process from AIS, making special emphasis on the role of tPA and uPA in this process.
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Affiliation(s)
- Valerie Jeanneret
- Department of Neurology & Center for Neurodegenerative Disease, Emory University School of Medicine, Whitehead Biomedical Research Building, 615 Michael Street, Suite 505J, Atlanta, GA, 30322, USA
| | - Manuel Yepes
- Department of Neurology & Center for Neurodegenerative Disease, Emory University School of Medicine, Whitehead Biomedical Research Building, 615 Michael Street, Suite 505J, Atlanta, GA, 30322, USA. .,Department of Neurology, Veterans Affairs Medical Center, Atlanta, GA, USA.
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Abstract
UNLABELLED Experience-dependent cortical plasticity declines with age. At the molecular level, experience-dependent proteolytic activity of tissue plasminogen activator (tPA) becomes restricted in the adult brain if mice are raised in standard cages. Understanding the mechanism for the loss of permissive proteolytic activity is therefore a key link for improving function in adult brains. Using the mouse primary visual cortex (V1) as a model, we demonstrate that tPA activity in V1 can be unmasked following 4 d of monocular deprivation when the mice older than 2 months are raised in standard cages by the genetic removal of Lynx1, a negative regulator of adult plasticity. This was also associated with the reduction of stubby and thin spine density and enhancement of ocular dominance shift in adult V1 of Lynx1 knock-out (KO) mice. These structural and functional changes were tPA-dependent because genetic removal of tPA in Lynx1 KO mice can block the monocular deprivation-dependent reduction of dendritic spine density, whereas both genetic and adult specific inhibition of tPA activity can ablate the ocular dominance shift in Lynx1 KO mice. Our work demonstrates that the adult brain has an intrinsic potential for experience-dependent elevation of proteolytic activity to express juvenile-like structural and functional changes but is effectively limited by Lynx1 if mice are raised in standard cages. Insights into the Lynx1-tPA plasticity mechanism may provide novel therapeutic targets for adult brain disorders. SIGNIFICANCE STATEMENT Experience-dependent proteolytic activity of tissue plasminogen activator (tPA) becomes restricted in the adult brain in correlation with the decline in cortical plasticity when mice are raised in standard cages. We demonstrated that removal of Lynx1, one of negative regulators of plasticity, unmasks experience-dependent tPA elevation in visual cortex of adult mice reared in standard cages. This proteolytic elevation facilitated dendritic spine reduction and ocular dominance plasticity in adult visual cortex. This is the first demonstration of adult brain to retain the intrinsic capacity to elevate tPA in an experience-dependent manner but is effectively limited by Lynx1. tPA-Lynx1 may potentially be a new candidate mechanism for interventions that were shown to activate plasticity in adult brain.
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50
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Wiera G, Mozrzymas JW. Extracellular proteolysis in structural and functional plasticity of mossy fiber synapses in hippocampus. Front Cell Neurosci 2015; 9:427. [PMID: 26582976 PMCID: PMC4631828 DOI: 10.3389/fncel.2015.00427] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 10/09/2015] [Indexed: 02/04/2023] Open
Abstract
Brain is continuously altered in response to experience and environmental changes. One of the underlying mechanisms is synaptic plasticity, which is manifested by modification of synapse structure and function. It is becoming clear that regulated extracellular proteolysis plays a pivotal role in the structural and functional remodeling of synapses during brain development, learning and memory formation. Clearly, plasticity mechanisms may substantially differ between projections. Mossy fiber synapses onto CA3 pyramidal cells display several unique functional features, including pronounced short-term facilitation, a presynaptically expressed long-term potentiation (LTP) that is independent of NMDAR activation, and NMDA-dependent metaplasticity. Moreover, structural plasticity at mossy fiber synapses ranges from the reorganization of projection topology after hippocampus-dependent learning, through intrinsically different dynamic properties of synaptic boutons to pre- and postsynaptic structural changes accompanying LTP induction. Although concomitant functional and structural plasticity in this pathway strongly suggests a role of extracellular proteolysis, its impact only starts to be investigated in this projection. In the present report, we review the role of extracellular proteolysis in various aspects of synaptic plasticity in hippocampal mossy fiber synapses. A growing body of evidence demonstrates that among perisynaptic proteases, tissue plasminogen activator (tPA)/plasmin system, β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) and metalloproteinases play a crucial role in shaping plastic changes in this projection. We discuss recent advances and emerging hypotheses on the roles of proteases in mechanisms underlying mossy fiber target specific synaptic plasticity and memory formation.
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Affiliation(s)
- Grzegorz Wiera
- Department of Animal Molecular Physiology, Institute of Experimental Biology, Wroclaw University Wroclaw, Poland ; Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Department of Animal Molecular Physiology, Institute of Experimental Biology, Wroclaw University Wroclaw, Poland ; Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University Wroclaw, Poland
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