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Okur Z, Schlauri N, Bitsikas V, Panopoulou M, Ortiz R, Schwaiger M, Karmakar K, Schreiner D, Scheiffele P. Control of neuronal excitation-inhibition balance by BMP-SMAD1 signalling. Nature 2024; 629:402-409. [PMID: 38632412 PMCID: PMC11078759 DOI: 10.1038/s41586-024-07317-z] [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: 02/23/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024]
Abstract
Throughout life, neuronal networks in the mammalian neocortex maintain a balance of excitation and inhibition, which is essential for neuronal computation1,2. Deviations from a balanced state have been linked to neurodevelopmental disorders, and severe disruptions result in epilepsy3-5. To maintain balance, neuronal microcircuits composed of excitatory and inhibitory neurons sense alterations in neural activity and adjust neuronal connectivity and function. Here we identify a signalling pathway in the adult mouse neocortex that is activated in response to increased neuronal network activity. Overactivation of excitatory neurons is signalled to the network through an increase in the levels of BMP2, a growth factor that is well known for its role as a morphogen in embryonic development. BMP2 acts on parvalbumin-expressing (PV) interneurons through the transcription factor SMAD1, which controls an array of glutamatergic synapse proteins and components of perineuronal nets. PV-interneuron-specific disruption of BMP2-SMAD1 signalling is accompanied by a loss of glutamatergic innervation in PV cells, underdeveloped perineuronal nets and decreased excitability. Ultimately, this impairment of the functional recruitment of PV interneurons disrupts the cortical excitation-inhibition balance, with mice exhibiting spontaneous epileptic seizures. Our findings suggest that developmental morphogen signalling is repurposed to stabilize cortical networks in the adult mammalian brain.
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Affiliation(s)
- Zeynep Okur
- Biozentrum, University of Basel, Basel, Switzerland
| | - Nadia Schlauri
- Biozentrum, University of Basel, Basel, Switzerland
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | | | - Raul Ortiz
- Biozentrum, University of Basel, Basel, Switzerland
| | - Michaela Schwaiger
- Swiss Institute of Bioinformatics, Basel, Switzerland
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Kajari Karmakar
- Biozentrum, University of Basel, Basel, Switzerland
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
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2
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Iwakura Y, Kobayashi Y, Namba H, Nawa H, Takei N. Epidermal Growth Factor Suppresses the Development of GABAergic Neurons Via the Modulation of Perineuronal Net Formation in the Neocortex of Developing Rodent Brains. Neurochem Res 2024; 49:1347-1358. [PMID: 38353896 DOI: 10.1007/s11064-024-04122-y] [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: 10/31/2023] [Revised: 02/02/2024] [Accepted: 02/04/2024] [Indexed: 04/04/2024]
Abstract
Previously, we reported that epidermal growth factor (EGF) suppresses GABAergic neuronal development in the rodent cortex. Parvalbumin-positive GABAergic neurons (PV neurons) have a unique extracellular structure, perineuronal nets (PNNs). PNNs are formed during the development of PV neurons and are mainly formed from chondroitin sulfate (CS) proteoglycans (CSPGs). We examined the effect of EGF on CSPG production and PNN formation as a potential molecular mechanism for the inhibition of inhibiting GABAergic neuronal development by EGF. In EGF-overexpressing transgenic (EGF-Tg) mice, the number of PNN-positive PV neurons was decreased in the cortex compared with that in wild-type mice, as in our previous report. The amount of CS and neurocan was also lower in the cortex of EGF-Tg mice, with a similar decrease observed in EGF-treated cultured cortical neurons. PD153035, an EGF receptor (ErbB1) kinase inhibitor, prevented those mentioned above excess EGF-induced reduction in PNN. We explored the molecular mechanism underlying the effect of EGF on PNNs using fluorescent substrates for matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs). EGF increased the enzyme activity of MMPs and ADAMs in cultured neurons. These enzyme activities were also increased in the EGF-Tg mice cortex. GM6001, a broad inhibitor of MMPs and ADAMs, also blocked EGF-induced PNN reductions. Therefore, EGF/EGF receptor signals may regulate PNN formation in the developing cortex.
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Affiliation(s)
- Yuriko Iwakura
- Department of Brain Tumor Biology, Brain Research Institute, Niigata University, Niigata, 951-8122, Japan.
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8122, Japan.
| | - Yutaro Kobayashi
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8122, Japan
- Department of Biochemistry, Graduate School of Medicine, Faculty of Medicine, University of Yamanashi, Yamanashi, 409-3898, Japan
| | - Hisaaki Namba
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8122, Japan
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama, 640-8156, Japan
| | - Hiroyuki Nawa
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8122, Japan
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama, 640-8156, Japan
| | - Nobuyuki Takei
- Department of Brain Tumor Biology, Brain Research Institute, Niigata University, Niigata, 951-8122, Japan
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8122, Japan
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Paveliev M, Egorchev AA, Musin F, Lipachev N, Melnikova A, Gimadutdinov RM, Kashipov AR, Molotkov D, Chickrin DE, Aganov AV. Perineuronal Net Microscopy: From Brain Pathology to Artificial Intelligence. Int J Mol Sci 2024; 25:4227. [PMID: 38673819 PMCID: PMC11049984 DOI: 10.3390/ijms25084227] [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: 02/02/2024] [Revised: 03/31/2024] [Accepted: 04/05/2024] [Indexed: 04/28/2024] Open
Abstract
Perineuronal nets (PNN) are a special highly structured type of extracellular matrix encapsulating synapses on large populations of CNS neurons. PNN undergo structural changes in schizophrenia, epilepsy, Alzheimer's disease, stroke, post-traumatic conditions, and some other brain disorders. The functional role of the PNN microstructure in brain pathologies has remained largely unstudied until recently. Here, we review recent research implicating PNN microstructural changes in schizophrenia and other disorders. We further concentrate on high-resolution studies of the PNN mesh units surrounding synaptic boutons to elucidate fine structural details behind the mutual functional regulation between the ECM and the synaptic terminal. We also review some updates regarding PNN as a potential pharmacological target. Artificial intelligence (AI)-based methods are now arriving as a new tool that may have the potential to grasp the brain's complexity through a wide range of organization levels-from synaptic molecular events to large scale tissue rearrangements and the whole-brain connectome function. This scope matches exactly the complex role of PNN in brain physiology and pathology processes, and the first AI-assisted PNN microscopy studies have been reported. To that end, we report here on a machine learning-assisted tool for PNN mesh contour tracing.
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Affiliation(s)
- Mikhail Paveliev
- Neuroscience Center, University of Helsinki, Haartmaninkatu 8, 00290 Helsinki, Finland
| | - Anton A. Egorchev
- Institute of Computational Mathematics and Information Technologies, Kazan Federal University, Kremlyovskaya 35, Kazan 420008, Tatarstan, Russia; (A.A.E.); (F.M.); (R.M.G.)
| | - Foat Musin
- Institute of Computational Mathematics and Information Technologies, Kazan Federal University, Kremlyovskaya 35, Kazan 420008, Tatarstan, Russia; (A.A.E.); (F.M.); (R.M.G.)
| | - Nikita Lipachev
- Institute of Physics, Kazan Federal University, Kremlyovskaya 16a, Kazan 420008, Tatarstan, Russia; (N.L.); (A.V.A.)
| | - Anastasiia Melnikova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Karl Marx 74, Kazan 420015, Tatarstan, Russia;
| | - Rustem M. Gimadutdinov
- Institute of Computational Mathematics and Information Technologies, Kazan Federal University, Kremlyovskaya 35, Kazan 420008, Tatarstan, Russia; (A.A.E.); (F.M.); (R.M.G.)
| | - Aidar R. Kashipov
- Institute of Artificial Intelligence, Robotics and Systems Engineering, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Tatarstan, Russia; (A.R.K.); (D.E.C.)
| | - Dmitry Molotkov
- Biomedicum Imaging Unit, University of Helsinki, Haartmaninkatu 8, 00014 Helsinki, Finland;
| | - Dmitry E. Chickrin
- Institute of Artificial Intelligence, Robotics and Systems Engineering, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Tatarstan, Russia; (A.R.K.); (D.E.C.)
| | - Albert V. Aganov
- Institute of Physics, Kazan Federal University, Kremlyovskaya 16a, Kazan 420008, Tatarstan, Russia; (N.L.); (A.V.A.)
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Tewari BP, Woo AM, Prim CE, Chaunsali L, Kimbrough IF, Engel K, Browning JL, Campbell SL, Sontheimer H. Perineuronal nets support astrocytic ion and glutamate homeostasis at tripartite synapses. RESEARCH SQUARE 2023:rs.3.rs-2501039. [PMID: 36778342 PMCID: PMC9915772 DOI: 10.21203/rs.3.rs-2501039/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Perineuronal nets (PNNs) are dense, negatively charged extracellular matrices that cover the cell body of fast-spiking inhibitory neurons. Synapses can be embedded and stabilized by PNNs believed to prevent synaptic plasticity. We find that in cortical fast-spiking interneurons synaptic terminals localize to perforations in the PNNs, 95% of which contain either excitatory or inhibitory synapses or both. The majority of terminals also colocalize with astrocytic processes expressing Kir4.1 as well as glutamate (Glu) and GABA transporters, hence can be considered tripartite synapses. In the adult brain, degradation of PNNs does not alter axonal terminals but causes expansion of astrocytic coverage of the neuronal somata. However, loss of PNNs impairs astrocytic transmitter and K+ uptake and causes spillage of synaptic Glu into the extrasynaptic space. This data suggests a hitherto unrecognized role of PNNs, to synergize with astrocytes to contain synaptically released signals.
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Affiliation(s)
- Bhanu P. Tewari
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - AnnaLin M. Woo
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Courtney E. Prim
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Lata Chaunsali
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Ian F. Kimbrough
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Kaliroi Engel
- School of Neuroscience, Virginia Tech, Blacksburg, VA, USA
| | | | | | - Harald Sontheimer
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
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Ali AB, Islam A, Constanti A. The fate of interneurons, GABA A receptor sub-types and perineuronal nets in Alzheimer's disease. Brain Pathol 2022; 33:e13129. [PMID: 36409151 PMCID: PMC9836378 DOI: 10.1111/bpa.13129] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/12/2022] [Indexed: 11/23/2022] Open
Abstract
Alzheimer's disease (AD) is the most common neurological disease, which is associated with gradual memory loss and correlated with synaptic hyperactivity and abnormal oscillatory rhythmic brain activity that precedes phenotypic alterations and is partly responsible for the spread of the disease pathology. Synaptic hyperactivity is thought to be because of alteration in the homeostasis of phasic and tonic synaptic inhibition, which is orchestrated by the GABAA inhibitory system, encompassing subclasses of interneurons and GABAA receptors, which play a vital role in cognitive functions, including learning and memory. Furthermore, the extracellular matrix, the perineuronal nets (PNNs) which often go unnoticed in considerations of AD pathology, encapsulate the inhibitory cells and neurites in critical brain regions and have recently come under the light for their crucial role in synaptic stabilisation and excitatory-inhibitory balance and when disrupted, serve as a potential trigger for AD-associated synaptic imbalance. Therefore, in this review, we summarise the current understanding of the selective vulnerability of distinct interneuron subtypes, their synaptic and extrasynaptic GABAA R subtypes as well as the changes in PNNs in AD, detailing their contribution to the mechanisms of disease development. We aim to highlight how seemingly unique malfunction in each component of the interneuronal GABA inhibitory system can be tied together to result in critical circuit dysfunction, leading to the irreversible symptomatic damage observed in AD.
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Tewari BP, Chaunsali L, Prim CE, Sontheimer H. A glial perspective on the extracellular matrix and perineuronal net remodeling in the central nervous system. Front Cell Neurosci 2022; 16:1022754. [PMID: 36339816 PMCID: PMC9630365 DOI: 10.3389/fncel.2022.1022754] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 09/23/2022] [Indexed: 11/18/2022] Open
Abstract
A structural scaffold embedding brain cells and vasculature is known as extracellular matrix (ECM). The physical appearance of ECM in the central nervous system (CNS) ranges from a diffused, homogeneous, amorphous, and nearly omnipresent matrix to highly organized distinct morphologies such as basement membranes and perineuronal nets (PNNs). ECM changes its composition and organization during development, adulthood, aging, and in several CNS pathologies. This spatiotemporal dynamic nature of the ECM and PNNs brings a unique versatility to their functions spanning from neurogenesis, cell migration and differentiation, axonal growth, and pathfinding cues, etc., in the developing brain, to stabilizing synapses, neuromodulation, and being an active partner of tetrapartite synapses in the adult brain. The malleability of ECM and PNNs is governed by both intrinsic and extrinsic factors. Glial cells are among the major extrinsic factors that facilitate the remodeling of ECM and PNN, thereby acting as key regulators of diverse functions of ECM and PNN in health and diseases. In this review, we discuss recent advances in our understanding of PNNs and how glial cells are central to ECM and PNN remodeling in normal and pathological states of the CNS.
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Abstract
Perineuronal nets (PNNs) are condensed extracellular matrix (ECM) assemblies of
polyanionic chondroitin sulfate proteoglycans, hyaluronan, and tenascins that
primarily wrap around GABAergic parvalbumin (PV) interneurons. During
development, PNN formation terminates the critical period of neuroplasticity, a
process that can be reversed by experimental disruption of PNNs. Perineuronal
nets also regulate the intrinsic properties of the enclosed PV neurons thereby
maintaining their inhibitory activity. Recent studies have implicated PNNs in
central nervous system diseases as well as PV neuron dysfunction; consequently,
they have further been associated with altered inhibition, particularly in the
genesis of epilepsy. A wide range of seizure presentations in human and rodent
models exhibit ECM remodeling with PNN disruption due to elevated protease
activity. Inhibition of PNN proteolysis reduces seizure activity suggesting that
PNN degrading enzymes may be potential novel therapeutic targets.
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Affiliation(s)
- Lata Chaunsali
- School of Neuroscience Graduate Program, Virginia Tech, Blacksburg, VA, USA.,Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Bhanu P Tewari
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Harald Sontheimer
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
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Crapser JD, Spangenberg EE, Barahona RA, Arreola MA, Hohsfield LA, Green KN. Microglia facilitate loss of perineuronal nets in the Alzheimer's disease brain. EBioMedicine 2020; 58:102919. [PMID: 32745992 PMCID: PMC7399129 DOI: 10.1016/j.ebiom.2020.102919] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Microglia, the brain's principal immune cell, are increasingly implicated in Alzheimer's disease (AD), but the molecular interfaces through which these cells contribute to amyloid beta (Aβ)-related neurodegeneration are unclear. We recently identified microglial contributions to the homeostatic and disease-associated modulation of perineuronal nets (PNNs), extracellular matrix structures that enwrap and stabilize neuronal synapses, but whether PNNs are altered in AD remains controversial. METHODS Extensive histological analysis was performed on male and female 5xFAD mice at 4, 8, 12, and 18 months of age to assess plaque burden, microgliosis, and PNNs. Findings were validated in postmortem AD tissue. The role of neuroinflammation in PNN loss was investigated via LPS treatment, and the ability to prevent or rescue disease-related reductions in PNNs was assessed by treating 5xFAD and 3xTg-AD model mice with colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 to deplete microglia. FINDINGS Utilizing the 5xFAD mouse model and human cortical tissue, we report that PNNs are extensively lost in AD in proportion to plaque burden. Activated microglia closely associate with and engulf damaged nets in the 5xFAD brain, and inclusions of PNN material are evident in mouse and human microglia, while aggrecan, a critical PNN component, deposits within human dense-core plaques. Disease-associated reductions in parvalbumin (PV)+ interneurons, frequently coated by PNNs, are preceded by PNN coverage and integrity impairments, and similar phenotypes are elicited in wild-type mice following microglial activation with LPS. Chronic pharmacological depletion of microglia prevents 5xFAD PNN loss, with similar results observed following depletion in aged 3xTg-AD mice, and this occurs despite plaque persistence. INTERPRETATION We conclude that phenotypically altered microglia facilitate plaque-dependent PNN loss in the AD brain. FUNDING The NIH (NIA, NINDS) and the Alzheimer's Association.
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Affiliation(s)
- Joshua D Crapser
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | | | - Rocio A Barahona
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Miguel A Arreola
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Lindsay A Hohsfield
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA.
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