101
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Perineuronal nets protect long-term memory by limiting activity-dependent inhibition from parvalbumin interneurons. Proc Natl Acad Sci U S A 2019; 116:27063-27073. [PMID: 31843906 DOI: 10.1073/pnas.1902680116] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Perineuronal nets (PNNs), a complex of extracellular matrix molecules that mostly surround GABAergic neurons in various brain regions, play a critical role in synaptic plasticity. The function and cellular mechanisms of PNNs in memory consolidation and reconsolidation processes are still not well understood. We hypothesized that PNNs protect long-term memory by limiting feedback inhibition from parvalbumin (PV) interneurons to projection neurons. Using behavioral, electrophysiological, and optogenetic approaches, we investigated the role of PNNs in fear memory consolidation and reconsolidation and GABAergic long-term potentiation (LTP). We made the discovery that the formation of PNNs was promoted by memory events in the hippocampus (HP), and we also demonstrated that PNN formation in both the HP and the anterior cingulate cortex (ACC) is essential for memory consolidation and reconsolidation of recent and remote memories. Removal of PNNs resulted in evident LTP impairments, which were rescued by acute application of picrotoxin, a GABAA receptor blocker, indicating that enhanced inhibition was the cause of the LTP impairments induced by PNN removal. Moreover, removal of PNNs switched GABAA receptor-mediated long-term depression to LTP through a presynaptic mechanism. Furthermore, the reduced activity of PV interneurons surrounded by PNNs regulated theta oscillations during fear memory consolidation. Finally, optogenetically suppressing PV interneurons rescued the memory impairment caused by removal of PNNs. Altogether, these results unveil the function of PV interneurons surrounding PNNs in protecting recent and remote contextual memory through the regulation of PV neuron GABA release.
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102
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Potassium and glutamate transport is impaired in scar-forming tumor-associated astrocytes. Neurochem Int 2019; 133:104628. [PMID: 31825815 PMCID: PMC6957761 DOI: 10.1016/j.neuint.2019.104628] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 01/09/2023]
Abstract
Unprovoked recurrent seizures are a serious comorbidity affecting most patients who suffer from glioma, a primary brain tumor composed of malignant glial cells. Cellular mechanisms contributing to the development of recurrent spontaneous seizures include the release of the excitatory neurotransmitter glutamate from glioma into extracellular space. Under physiological conditions, astrocytes express two high affinity glutamate transporters, Glt-1 and Glast, which are responsible for the removal of excess extracellular glutamate. In the context of neurological disease or brain injury, astrocytes become reactive which can negatively affect neuronal function, causing hyperexcitability and/or death. Using electrophysiology, immunohistochemistry, fluorescent in situ hybridization, and Western blot analysis in different orthotopic xenograft and allograft models of human and mouse gliomas, we find that peritumoral astrocytes exhibit astrocyte scar formation characterized by proliferation, cellular hypertrophy, process elongation, and increased GFAP and pSTAT3. Overall, peritumoral reactive astrocytes show a significant reduction in glutamate and potassium uptake, as well as decreased glutamine synthetase activity. A subset of peritumoral astrocytes displayed a depolarized resting membrane potential, further contributing to reduced potassium and glutamate homeostasis. These changes may contribute to the propagation of peritumoral neuronal hyperexcitability and excitotoxic death.
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103
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Gill BJA, Wu X, Khan FA, Sosunov AA, Liou JY, Dovas A, Eissa TL, Banu MA, Bateman LM, McKhann GM, Canoll P, Schevon C. Ex vivo multi-electrode analysis reveals spatiotemporal dynamics of ictal behavior at the infiltrated margin of glioma. Neurobiol Dis 2019; 134:104676. [PMID: 31731042 PMCID: PMC8147009 DOI: 10.1016/j.nbd.2019.104676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/22/2019] [Accepted: 11/11/2019] [Indexed: 01/02/2023] Open
Abstract
The purpose of this study is to develop a platform in which the cellular and molecular underpinnings of chronic focal neocortical lesional epilepsy can be explored and use it to characterize seizure-like events (SLEs) in an ex vivo model of infiltrating high-grade glioma. Microelectrode arrays were used to study electrophysiologic changes in ex vivo acute brain slices from a PTEN/p53 deleted, PDGF-B driven mouse model of high-grade glioma. Electrode locations were co-registered to the underlying histology to ascertain the influence of the varying histologic landscape on the observed electrophysiologic changes. Peritumoral, infiltrated, and tumor sites were sampled in tumor-bearing slices. Following the addition of zero Mg2+ solution, all three histologic regions in tumor-bearing slices showed significantly greater increases in firing rates when compared to the control sites. Tumor-bearing slices demonstrated increased proclivity for SLEs, with 40 events in tumor-bearing slices and 5 events in control slices (p-value = .0105). Observed SLEs were characterized by either low voltage fast (LVF) onset patterns or short bursts of repetitive widespread, high amplitude low frequency discharges. Seizure foci comprised areas from all three histologic regions. The onset electrode was found to be at the infiltrated margin in 50% of cases and in the peritumoral region in 36.9% of cases. These findings reveal a landscape of histopathologic and electrophysiologic alterations associated with ictogenesis and spread of tumor-associated seizures.
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Affiliation(s)
- Brian J A Gill
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA.
| | - Xiaoping Wu
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Farhan A Khan
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Alexander A Sosunov
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Jyun-You Liou
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Athanassios Dovas
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Tahra L Eissa
- Department of Applied Mathematics, University of Colorado at Boulder, Boulder, CO, USA
| | - Matei A Banu
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Lisa M Bateman
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Peter Canoll
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Catherine Schevon
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
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104
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Bozzelli PL, Caccavano A, Avdoshina V, Mocchetti I, Wu JY, Conant K. Increased matrix metalloproteinase levels and perineuronal net proteolysis in the HIV-infected brain; relevance to altered neuronal population dynamics. Exp Neurol 2019; 323:113077. [PMID: 31678140 DOI: 10.1016/j.expneurol.2019.113077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 09/06/2019] [Accepted: 10/01/2019] [Indexed: 12/11/2022]
Abstract
HIV-associated neurocognitive disorders (HAND) continue to persist despite effective control of viral replication. Although the mechanisms underlying HAND are poorly understood, recent attention has focused on altered neuronal population activity as a correlate of impaired cognition. However, while alterations in neuronal population activity in the gamma frequency range are noted in the setting of HAND, the underlying mechanisms for these changes is unclear. Perineuronal nets (PNNs) are a specialized extracellular matrix that surrounds a subset of inhibitory neurons important to the expression of neuronal oscillatory activity. In the present study, we observe that levels of PNN-degrading matrix metalloproteinases (MMPs) are elevated in HIV-infected post-mortem human brain tissue. Furthermore, analysis of two PNN components, aggrecan and brevican, reveals increased proteolysis in HIV-infected brains. In addition, local field potential recordings from ex vivo mouse hippocampal slices demonstrate that the power of carbachol-induced gamma activity is increased following PNN degradation. Together, these results provide a possible mechanism whereby increased MMP proteolysis of PNNs may stimulate altered neuronal oscillatory activity and contribute to HAND symptoms.
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Affiliation(s)
- P Lorenzo Bozzelli
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Adam Caccavano
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA; Department of Pharmacology, Georgetown University Medical Center, Washington, DC, USA
| | - Valeria Avdoshina
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Italo Mocchetti
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Jian-Young Wu
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Katherine Conant
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA; Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA.
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105
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Balashova A, Pershin V, Zaborskaya O, Tkachenko N, Mironov A, Guryev E, Kurbatov L, Gainullin M, Mukhina I. Enzymatic Digestion of Hyaluronan-Based Brain Extracellular Matrix in vivo Can Induce Seizures in Neonatal Mice. Front Neurosci 2019; 13:1033. [PMID: 31632233 PMCID: PMC6779145 DOI: 10.3389/fnins.2019.01033] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/12/2019] [Indexed: 01/08/2023] Open
Abstract
It is well-known that hyaluronic acid (HA) as a component of brain extracellular matrix (ECM) plays a pivotal role in the nervous system and is involved in synaptic plasticity changes in vascular cognitive impairment and dementia. HA breakdown is a feature of the acute stage of stroke injury and may be detrimental through enhancement of the inflammatory response. Recent studies have shown that knockout mice lacking hyaluronic acid synthetase demonstrates epileptic phenotype in vivo and removal of HA leads to delayed development of epileptiform activity in cultured hippocampal neurons in vitro. Here, we studied whether digestion of hyaluronic acid in the hippocampus in early postnatal period can trigger seizures. Hyaluronidase (Hyal) (5 U/μl) was bilaterally injected into C57BL/6j mice (P17) CA1 field of hippocampus using the stereotaxic method to remove hyaluronan-based ECM. Transcriptome analysis of hippocampal tissue 2 h after enzymatic digestion of hyaluronan-based brain ECM revealed increased gene expression of proteins involved in inflammation reactions (TLR2, CCL2,3,5), neuroinflammation, axonal guidance and ephrin receptor signaling, versus the vehicle group. Mice injected with hyaluronidase exhibited delayed audiogenic seizures and improvement in working memory 72 h after injection, while there were no changes in locomotor activity, anxious level and exploratory behavior due to the open field test. The obtained results point to a link between the activation of neuroinflammation by enzymatic digestion of hyaluronan-based brain ECM during the neonatal period and their subsequent reactivity to seizures, which may play an important role in the functional features of the developing brain, including its seizure propensity.
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Affiliation(s)
- Alena Balashova
- Laboratory for Brain Extracellular Matrix Research, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Vladimir Pershin
- Laboratory for Brain Extracellular Matrix Research, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Cell Technology Group, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Olga Zaborskaya
- Laboratory for Brain Extracellular Matrix Research, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Cell Technology Group, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Natalia Tkachenko
- Laboratory for Brain Extracellular Matrix Research, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Cell Technology Group, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Andrey Mironov
- Laboratory for Brain Extracellular Matrix Research, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Cell Technology Group, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Evgeny Guryev
- Laboratory for Brain Extracellular Matrix Research, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Cell Technology Group, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Leonid Kurbatov
- V. N. Orekhovich Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Moscow, Russia
| | - Murat Gainullin
- Cell Technology Group, Privolzhsky Research Medical University, Nizhny Novgorod, Russia.,Norwegian PSC Research Center and Institute of Clinical Medicine, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Irina Mukhina
- Laboratory for Brain Extracellular Matrix Research, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Cell Technology Group, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
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106
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Schevon CA, Tobochnik S, Eissa T, Merricks E, Gill B, Parrish RR, Bateman LM, McKhann GM, Emerson RG, Trevelyan AJ. Multiscale recordings reveal the dynamic spatial structure of human seizures. Neurobiol Dis 2019; 127:303-311. [PMID: 30898669 PMCID: PMC6588430 DOI: 10.1016/j.nbd.2019.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/11/2019] [Accepted: 03/15/2019] [Indexed: 02/07/2023] Open
Abstract
The cellular activity underlying human focal seizures, and its relationship to key signatures in the EEG recordings used for therapeutic purposes, has not been well characterized despite many years of investigation both in laboratory and clinical settings. The increasing use of microelectrodes in epilepsy surgery patients has made it possible to apply principles derived from laboratory research to the problem of mapping the spatiotemporal structure of human focal seizures, and characterizing the corresponding EEG signatures. In this review, we describe results from human microelectrode studies, discuss some data interpretation pitfalls, and explain the current understanding of the key mechanisms of ictogenesis and seizure spread.
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Affiliation(s)
- Catherine A Schevon
- Department of Neurology, Columbia University Medical Center, New York, NY, USA.
| | - Steven Tobochnik
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Tahra Eissa
- Department of Applied Mathematics, University of Colorado at Boulder, Boulder, CO, USA
| | - Edward Merricks
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Brian Gill
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - R Ryley Parrish
- Institute for Aging, Newcastle University, Newcastle-Upon-Tyne, UK
| | - Lisa M Bateman
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Ronald G Emerson
- Department of Neurology, Weill Cornell Medical Center, New York, NY, USA
| | - Andrew J Trevelyan
- Department of Neurology, Columbia University Medical Center, New York, NY, USA; Institute for Aging, Newcastle University, Newcastle-Upon-Tyne, UK
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107
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Tewari BP, Sontheimer H. Protocol to quantitatively assess the structural integrity of Perineuronal Nets ex vivo. Bio Protoc 2019; 9:e3234. [PMID: 33654764 PMCID: PMC7854210 DOI: 10.21769/bioprotoc.3234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/16/2019] [Accepted: 04/20/2019] [Indexed: 01/25/2023] Open
Abstract
Perineuronal nets (PNNs) are extracellular matrix assemblies of highly negatively charged proteoglycans that wrap around fast-spiking parvalbumin (PV) expressing interneurons in the cerebral cortex. PNNs play important roles in neuronal plasticity and modulate biophysical properties of the enclosed interneurons. Various central nervous system diseases including schizophrenia, Alzheimer disease and epilepsy present with qualitative alteration in PNNs, however prior studies failed to quantitatively assess such changes at single PNN level and correlate them with functional changes in disease. We describe a method to quantify the structural integrity of PNNs using high magnification image analysis of Wisteria Floribunda Agglutinin (WFA)-labeled PNNs in combination with cell-type-specific marker such as PV and NeuN. A polyline intensity profile of WFA along the entire perimeter of cell shows alternate segments with and without WFA labeling, indicating the intact chondroitin sulfate proteoglycan (CSPG) and holes of PNN respectively. This line intensity profile defines CSPG peaks, where intact PNN is present, and CSPG valleys (holes) where the PNN is missing. The average number of peaks reflect the integrity of the lattice assembly of PNN. The average size of PNN holes can be readily computed using image analysis software. Furthermore, degradation of PNNs using a bacterial-derived enzyme, Chondroitinase ABC (ChABC), allows to experimentally manipulate PNNs in situ brain slices during which biophysical properties can be assessed by patch-clamp recordings. We describe optimized experimental parameters to degrade PNNs in brain slices before as well as during recordings to study the possible change in function in real time. Our protocols provide effective and appropriate methods to modulate and quantify the PNN's experimental manipulations.
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Affiliation(s)
- Bhanu P. Tewari
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at VTC, 2 Riverside Cir., Roanoke, VA 24016, USA
| | - Harald Sontheimer
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at VTC, 2 Riverside Cir., Roanoke, VA 24016, USA
- School of Neuroscience, College of Science, Virginia Tech, 300 Turner Street NW, Blacksburg, VA 24061, USA
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108
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Alaiyed S, Conant K. A Role for Matrix Metalloproteases in Antidepressant Efficacy. Front Mol Neurosci 2019; 12:117. [PMID: 31133801 PMCID: PMC6517485 DOI: 10.3389/fnmol.2019.00117] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 04/24/2019] [Indexed: 01/10/2023] Open
Abstract
Major depressive disorder is a debilitating condition that affects approximately 15% of the United States population. Though the neurophysiological mechanisms that underlie this disorder are not completely understood, both human and rodent studies suggest that excitatory/inhibitory (E/I) balance is reduced with the depressive phenotype. In contrast, antidepressant efficacy in responsive individuals correlates with increased excitatory neurotransmission in select brain regions, suggesting that the restoration of E/I balance may improve mood. Enhanced excitatory transmission can occur through mechanisms including increased dendritic arborization and synapse formation in pyramidal neurons. Reduced activity of inhibitory neurons may also contribute to antidepressant efficacy. Consistent with this possibility, the fast-acting antidepressant ketamine may act by selective inhibition of glutamatergic input to GABA releasing parvalbumin (PV)-expressing interneurons. Recent work has also shown that a negative allosteric modulator of the GABA-A receptor α subunit can improve depression-related behavior. PV-expressing interneurons are thought to represent critical pacemakers for synchronous network events. These neurons also represent the predominant GABAergic neuronal population that is enveloped by the perineuronal net (PNN), a lattice-like structure that is thought to stabilize glutamatergic input to this cell type. Disruption of the PNN reduces PV excitability and increases pyramidal cell excitability. Various antidepressant medications increase the expression of matrix metalloproteinases (MMPs), enzymes that can increase pyramidal cell dendritic arborization and spine formation. MMPs can also cleave PNN proteins to reduce PV neuron-mediated inhibition. The present review will focus on mechanisms that may underlie antidepressant efficacy, with a focus on monoamines as facilitators of increased matrix metalloprotease (MMP) expression and activation. Discussion will include MMP-dependent effects on pyramidal cell structure and function, as well as MMP-dependent effects on PV expressing interneurons. We conclude with discussion of antidepressant use for those at risk for Alzheimer’s disease, and we also highlight areas for further study.
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Affiliation(s)
- Seham Alaiyed
- Department of Pharmacology, Georgetown University Medical Center, Washington, DC, United States
| | - Katherine Conant
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, United States
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109
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Alaiyed S, Bozzelli PL, Caccavano A, Wu JY, Conant K. Venlafaxine stimulates PNN proteolysis and MMP-9-dependent enhancement of gamma power; relevance to antidepressant efficacy. J Neurochem 2019; 148:810-821. [PMID: 30697747 DOI: 10.1111/jnc.14671] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/30/2018] [Accepted: 01/23/2019] [Indexed: 01/15/2023]
Abstract
Drugs that target monoaminergic transmission represent a first-line treatment for major depression. Though a full understanding of the mechanisms that underlie antidepressant efficacy is lacking, evidence supports a role for enhanced excitatory transmission. This can occur through two non-mutually exclusive mechanisms. The first involves increased function of excitatory neurons through relatively direct mechanisms such as enhanced dendritic arborization. Another mechanism involves reduced inhibitory function, which occurs with the rapid antidepressant ketamine. Consistent with this, GABAergic interneuron-mediated cortical inhibition is linked to reduced gamma oscillatory power, a rhythm also diminished in depression. Remission of depressive symptoms correlates with restoration of gamma power. As a result of strong excitatory input, reliable GABA release, and fast firing, PV-expressing neurons (PV neurons) represent critical pacemakers for synchronous oscillations. PV neurons also represent the predominant GABAergic population enveloped by perineuronal nets (PNNs), lattice-like structures that localize glutamatergic input. Disruption of PNNs reduces PV excitability and enhances gamma activity. Studies suggest that monoamine reuptake inhibitors reduce integrity of the PNN. Mechanisms by which these inhibitors reduce PNN integrity, however, remain largely unexplored. A better understanding of these issues might encourage development of therapeutics that best up-regulate PNN-modulating proteases. We observe that the serotonin/norepinephrine reuptake inhibitor venlafaxine increases hippocampal matrix metalloproteinase (MMP)-9 levels as determined by ELISA and concomitantly reduces PNN integrity in murine hippocampus as determined by analysis of sections following their staining with a fluorescent PNN-binding lectin. Moreover, venlafaxine-treated mice (30 mg/kg/day) show an increase in carbachol-induced gamma power in ex vivo hippocampal slices as determined by local field potential recording and Matlab analyses. Studies with mice deficient in matrix metalloproteinase 9 (MMP-9), a protease linked to PNN disruption in other settings, suggest that MMP-9 contributes to venlafaxine-enhanced gamma power. In conclusion, our results support the possibility that MMP-9 activity contributes to antidepressant efficacy through effects on the PNN that may in turn enhance neuronal population dynamics involved in mood and/or memory. Cover Image for this issue: doi: 10.1111/jnc.14498.
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Affiliation(s)
- Seham Alaiyed
- Departments of Pharmacology, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - P Lorenzo Bozzelli
- Departments of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA.,Departments of Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Adam Caccavano
- Departments of Pharmacology, Georgetown University Medical Center, Washington, District of Columbia, USA.,Departments of Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Jian Young Wu
- Departments of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA.,Departments of Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Katherine Conant
- Departments of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA.,Departments of Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA
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