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Deshpande K, Martirosian V, Nakamura BN, Das D, Iyer M, Reed M, Shao L, Bamshad D, Buckley NJ, Neman J. SRRM4-mediated REST to REST4 dysregulation promotes tumor growth and neural adaptation in breast cancer leading to brain metastasis. Neuro Oncol 2024; 26:309-322. [PMID: 37716001 PMCID: PMC10836770 DOI: 10.1093/neuonc/noad175] [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: 04/14/2023] [Indexed: 09/18/2023] Open
Abstract
BACKGROUND Effective control of brain metastasis remains an urgent clinical need due a limited understanding of the mechanisms driving it. Although the gain of neuro-adaptive attributes in breast-to-brain metastases (BBMs) has been described, the mechanisms that govern this neural acclimation and the resulting brain metastasis competency are poorly understood. Herein, we define the role of neural-specific splicing factor Serine/Arginine Repetitive Matrix Protein 4 (SRRM4) in regulating microenvironmental adaptation and brain metastasis colonization in breast cancer cells. METHODS Utilizing pure neuronal cultures and brain-naive and patient-derived BM tumor cells, along with in vivo tumor modeling, we surveyed the early induction of mediators of neural acclimation in tumor cells. RESULTS When SRRM4 is overexpressed in systemic breast cancer cells, there is enhanced BBM leading to poorer overall survival in vivo. Concomitantly, SRRM4 knockdown expression does not provide any advantage in central nervous system metastasis. In addition, reducing SRRM4 expression in breast cancer cells slows down proliferation and increases resistance to chemotherapy. Conversely, when SRRM4/REST4 levels are elevated, tumor cell growth is maintained even in nutrient-deprived conditions. In neuronal coculture, decreasing SRRM4 expression in breast cancer cells impairs their ability to adapt to the brain microenvironment, while increasing SRRM4/RE-1 Silencing Transcription Factor (REST4) levels leads to greater expression of neurotransmitter and synaptic signaling mediators and a significant colonization advantage. CONCLUSIONS Collectively, our findings identify SRRM4 as a regulator of brain metastasis colonization, and a potential therapeutic target in breast cancer.
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Affiliation(s)
- Krutika Deshpande
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- USC Brain Tumor Center, Keck School of Medicine, University of Southern California, Los Angeles, California, USA)
| | - Vahan Martirosian
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- USC Brain Tumor Center, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Brooke N Nakamura
- Division of Gastrointestinal and Liver Diseases, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- USC Brain Tumor Center, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Diganta Das
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- USC Brain Tumor Center, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Mukund Iyer
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- USC Brain Tumor Center, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Max Reed
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Ling Shao
- Division of Gastrointestinal and Liver Diseases, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Daniella Bamshad
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Noel J Buckley
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Josh Neman
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- USC Brain Tumor Center, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Arévalo JC, Deogracias R. Mechanisms Controlling the Expression and Secretion of BDNF. Biomolecules 2023; 13:biom13050789. [PMID: 37238659 DOI: 10.3390/biom13050789] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/19/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
Brain-derived nerve factor (BDNF), through TrkB receptor activation, is an important modulator for many different physiological and pathological functions in the nervous system. Among them, BDNF plays a crucial role in the development and correct maintenance of brain circuits and synaptic plasticity as well as in neurodegenerative diseases. The proper functioning of the central nervous system depends on the available BDNF concentrations, which are tightly regulated at transcriptional and translational levels but also by its regulated secretion. In this review we summarize the new advances regarding the molecular players involved in BDNF release. In addition, we will address how changes of their levels or function in these proteins have a great impact in those functions modulated by BDNF under physiological and pathological conditions.
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Affiliation(s)
- Juan Carlos Arévalo
- Department of Cell Biology and Pathology, Institute of Neurosciences of Castille and Leon (INCyL), University of Salamanca, 37007 Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), 37007 Salamanca, Spain
| | - Rubén Deogracias
- Department of Cell Biology and Pathology, Institute of Neurosciences of Castille and Leon (INCyL), University of Salamanca, 37007 Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), 37007 Salamanca, Spain
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3
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Costa RO, Martins LF, Tahiri E, Duarte CB. Brain-derived neurotrophic factor-induced regulation of RNA metabolism in neuronal development and synaptic plasticity. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1713. [PMID: 35075821 DOI: 10.1002/wrna.1713] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/17/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) plays multiple roles in the nervous system, including in neuronal development, in long-term synaptic potentiation in different brain regions, and in neuronal survival. Alterations in these regulatory mechanisms account for several diseases of the nervous system. The synaptic effects of BDNF mediated by activation of tropomyosin receptor kinase B (TrkB) receptors are partly mediated by stimulation of local protein synthesis which is now considered a ubiquitous feature in both presynaptic and postsynaptic compartments of the neuron. The capacity to locally synthesize proteins is of great relevance at several neuronal developmental stages, including during neurite development, synapse formation, and stabilization. The available evidence shows that the effects of BDNF-TrkB signaling on local protein synthesis regulate the structure and function of the developing and mature synapses. While a large number of studies have illustrated a wide range of effects of BDNF on the postsynaptic proteome, a growing number of studies also point to presynaptic effects of the neurotrophin in the local regulation of the protein composition at the presynaptic level. Here, we will review the latest evidence on the role of BDNF in local protein synthesis, comparing the effects on the presynaptic and postsynaptic compartments. Additionally, we overview the relevance of BDNF-associated local protein synthesis in neuronal development and synaptic plasticity, at the presynaptic and postsynaptic compartments, and their relevance in terms of disease. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Export and Localization > RNA Localization.
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Affiliation(s)
- Rui O Costa
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Luís F Martins
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Emanuel Tahiri
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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Williams RA, Johnson KW, Lee FS, Hemmings HC, Platholi J. A Common Human Brain-Derived Neurotrophic Factor Polymorphism Leads to Prolonged Depression of Excitatory Synaptic Transmission by Isoflurane in Hippocampal Cultures. Front Mol Neurosci 2022; 15:927149. [PMID: 35813074 PMCID: PMC9260310 DOI: 10.3389/fnmol.2022.927149] [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: 04/23/2022] [Accepted: 06/07/2022] [Indexed: 12/02/2022] Open
Abstract
Multiple presynaptic and postsynaptic targets have been identified for the reversible neurophysiological effects of general anesthetics on synaptic transmission and neuronal excitability. However, the synaptic mechanisms involved in persistent depression of synaptic transmission resulting in more prolonged neurological dysfunction following anesthesia are less clear. Here, we show that brain-derived neurotrophic factor (BDNF), a growth factor implicated in synaptic plasticity and dysfunction, enhances glutamate synaptic vesicle exocytosis, and that attenuation of vesicular BDNF release by isoflurane contributes to transient depression of excitatory synaptic transmission in mice. This reduction in synaptic vesicle exocytosis by isoflurane was acutely irreversible in neurons that release less endogenous BDNF due to a polymorphism (BDNF Val66Met; rs6265) compared to neurons from wild-type mice. These effects were prevented by exogenous application of BDNF. Our findings identify a role for a common human BDNF single nucleotide polymorphism in persistent changes of synaptic function following isoflurane exposure. These short-term persistent alterations in excitatory synaptic transmission indicate a role for human genetic variation in anesthetic effects on synaptic plasticity and neurocognitive function.
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Affiliation(s)
- Riley A. Williams
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States
| | - Kenneth W. Johnson
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, United States
| | - Francis S. Lee
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, United States,Department of Psychiatry, Sackler Institute for Developmental Psychobiology, Weill Cornell Medicine, New York, NY, United States,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, United States
| | - Hugh C. Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States,Department of Pharmacology, Weill Cornell Medicine, New York, NY, United States
| | - Jimcy Platholi
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, United States,*Correspondence: Jimcy Platholi,
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Platholi J, Hemmings HC. Effects of general anesthetics on synaptic transmission and plasticity. Curr Neuropharmacol 2021; 20:27-54. [PMID: 34344292 PMCID: PMC9199550 DOI: 10.2174/1570159x19666210803105232] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 11/22/2022] Open
Abstract
General anesthetics depress excitatory and/or enhance inhibitory synaptic transmission principally by modulating the function of glutamatergic or GABAergic synapses, respectively, with relative anesthetic agent-specific mechanisms. Synaptic signaling proteins, including ligand- and voltage-gated ion channels, are targeted by general anesthetics to modulate various synaptic mechanisms, including presynaptic neurotransmitter release, postsynaptic receptor signaling, and dendritic spine dynamics to produce their characteristic acute neurophysiological effects. As synaptic structure and plasticity mediate higher-order functions such as learning and memory, long-term synaptic dysfunction following anesthesia may lead to undesirable neurocognitive consequences depending on the specific anesthetic agent and the vulnerability of the population. Here we review the cellular and molecular mechanisms of transient and persistent general anesthetic alterations of synaptic transmission and plasticity.
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Affiliation(s)
- Jimcy Platholi
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
| | - Hugh C Hemmings
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
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Long-term Administration of Salicylate-induced Changes in BDNF Expression and CREB Phosphorylation in the Auditory Cortex of Rats. Otol Neurotol 2019; 39:e173-e180. [PMID: 29342042 PMCID: PMC5821486 DOI: 10.1097/mao.0000000000001717] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We investigated whether salicylate induces tinnitus through alteration of the expression levels of brain-derived neurotrophic factor (BDNF), proBDNF, tyrosine kinase receptor B (TrkB), cAMP-responsive element-binding protein (CREB), and phosphorylated CREB (p-CREB) in the auditory cortex (AC).
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Chronic Electrical Stimulation Promotes the Excitability and Plasticity of ESC-derived Neurons following Glutamate-induced Inhibition In vitro. Sci Rep 2018; 8:10957. [PMID: 30026496 PMCID: PMC6053382 DOI: 10.1038/s41598-018-29069-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 07/02/2018] [Indexed: 01/07/2023] Open
Abstract
Functional electrical stimulation (FES) is rapidly gaining traction as a therapeutic tool for mediating the repair and recovery of the injured central nervous system (CNS). However, the underlying mechanisms and impact of these stimulation paradigms at a molecular, cellular and network level remain largely unknown. In this study, we used embryonic stem cell (ESC)-derived neuron and glial co-cultures to investigate network maturation following acute administration of L-glutamate, which is a known mediator of excitotoxicity following CNS injury. We then modulated network maturation using chronic low frequency stimulation (LFS) and direct current stimulation (DCS) protocols. We demonstrated that L-glutamate impaired the rate of maturation of ESC-derived neurons and glia immediately and over a week following acute treatment. The administration of chronic LFS and DCS protocols individually following L-glutamate infusion significantly promoted the excitability of neurons as well as network synchrony, while the combination of LFS/DCS did not. qRT-PCR analysis revealed that LFS and DCS alone significantly up-regulated the expression of excitability and plasticity-related transcripts encoding N-methyl-D-aspartate (NMDA) receptor subunit (NR2A), brain-derived neurotrophic factor (BDNF) and Ras-related protein (RAB3A). In contrast, the simultaneous administration of LFS/DCS down-regulated BDNF and RAB3A expression. Our results demonstrate that LFS and DCS stimulation can modulate network maturation excitability and synchrony following the acute administration of an inhibitory dose of L-glutamate, and upregulate NR2A, BDNF and RAB3A gene expression. Our study also provides a novel framework for investigating the effects of electrical stimulation on neuronal responses and network formation and repair after traumatic brain injury.
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Saito A, Cai L, Matsuhisa K, Ohtake Y, Kaneko M, Kanemoto S, Asada R, Imaizumi K. Neuronal activity-dependent local activation of dendritic unfolded protein response promotes expression of brain-derived neurotrophic factor in cell soma. J Neurochem 2017; 144:35-49. [PMID: 28921568 PMCID: PMC5765399 DOI: 10.1111/jnc.14221] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/21/2017] [Accepted: 09/08/2017] [Indexed: 12/20/2022]
Abstract
Unfolded protein response (UPR) has roles not only in resolving the accumulation of unfolded proteins owing to endoplasmic reticulum (ER) stress, but also in regulation of cellular physiological functions. ER stress transducers providing the branches of UPR signaling are known to localize in distal dendritic ER of neurons. These reports suggest that local activation of UPR branches may produce integrated outputs for distant communication, and allow regulation of local events in highly polarized neurons. Here, we demonstrated that synaptic activity‐ and brain‐derived neurotrophic factor (BDNF)‐dependent local activation of UPR signaling could be associated with dendritic functions through retrograde signal propagation by using murine neuroblastoma cell line, Neuro‐2A and primary cultured hippocampal neurons derived from postnatal day 0 litter C57BL/6 mice. ER stress transducer, inositol‐requiring kinase 1 (IRE1), was activated at postsynapses in response to excitatory synaptic activation. Activated dendritic IRE1 accelerated accumulation of the downstream transcription factor, x‐box‐binding protein 1 (XBP1), in the nucleus. Interestingly, excitatory synaptic activation‐dependent up‐regulation of XBP1 directly facilitated transcriptional activation of BDNF. BDNF in turn drove its own expression via IRE1‐XBP1 pathway in a protein kinase A‐dependent manner. Exogenous treatment with BDNF promoted extension and branching of dendrites through the protein kinase A‐IRE1‐XBP1 cascade. Taken together, our findings indicate novel mechanisms for communication between soma and distal sites of polarized neurons that are coordinated by local activation of IRE1‐XBP1 signaling. Synaptic activity‐ and BDNF‐dependent distinct activation of dendritic IRE1‐XBP1 cascade drives BDNF expression in cell soma and may be involved in dendritic extension. Cover Image for this issue: doi. 10.1111/jnc.14159. ![]()
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Affiliation(s)
- Atsushi Saito
- Department of Stress Protein Processing, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Longjie Cai
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Koji Matsuhisa
- Department of Stress Protein Processing, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Yosuke Ohtake
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Masayuki Kaneko
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Soshi Kanemoto
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Rie Asada
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
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Hypertension-induced synapse loss and impairment in synaptic plasticity in the mouse hippocampus mimics the aging phenotype: implications for the pathogenesis of vascular cognitive impairment. GeroScience 2017; 39:385-406. [PMID: 28664509 DOI: 10.1007/s11357-017-9981-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 05/30/2017] [Indexed: 12/22/2022] Open
Abstract
Strong epidemiological and experimental evidence indicates that hypertension has detrimental effects on the cerebral microcirculation and thereby promotes accelerated brain aging. Hypertension is an independent risk factor for both vascular cognitive impairment (VCI) and Alzheimer's disease (AD). However, the pathophysiological link between hypertension-induced cerebromicrovascular injury (e.g., blood-brain barrier disruption, increased microvascular oxidative stress, and inflammation) and cognitive decline remains elusive. The present study was designed to characterize neuronal functional and morphological alterations induced by chronic hypertension and compare them to those induced by aging. To achieve that goal, we induced hypertension in young C57BL/6 mice by chronic (4 weeks) infusion of angiotensin II. We found that long-term potentiation (LTP) of performant path synapses following high-frequency stimulation of afferent fibers was decreased in hippocampal slices obtained from hypertensive mice, mimicking the aging phenotype. Hypertension and advanced age were associated with comparable decline in synaptic density in the stratum radiatum of the mouse hippocampus. Hypertension, similar to aging, was associated with changes in mRNA expression of several genes involved in regulation of neuronal function, including down-regulation of Bdnf, Homer1, and Dlg4, which may have a role in impaired synaptic plasticity. Collectively, hypertension impairs synaptic plasticity, reduces synaptic density, and promotes dysregulation of genes involved in synaptic function in the mouse hippocampus mimicking the aging phenotype. These hypertension-induced neuronal alterations may impair establishment of memories in the hippocampus and contribute to the pathogenesis and clinical manifestation of both vascular cognitive impairment (VCI) and Alzheimer's disease (AD).
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Neuropeptide VGF Promotes Maturation of Hippocampal Dendrites That Is Reduced by Single Nucleotide Polymorphisms. Int J Mol Sci 2017; 18:ijms18030612. [PMID: 28287464 PMCID: PMC5372628 DOI: 10.3390/ijms18030612] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/03/2017] [Accepted: 03/08/2017] [Indexed: 12/13/2022] Open
Abstract
The neuropeptide VGF (non-acronymic) is induced by brain-derived neurotrophic factor and promotes hippocampal neurogenesis, as well as synaptic activity. However, morphological changes induced by VGF have not been elucidated. Developing hippocampal neurons were exposed to VGF through bath application or virus-mediated expression in vitro. VGF-derived peptide, TLQP-62, enhanced dendritic branching, and outgrowth. Furthermore, VGF increased dendritic spine density and the proportion of immature spines. Spine formation was associated with increased synaptic protein expression and co-localization of pre- and postsynaptic markers. Three non-synonymous single nucleotide polymorphisms (SNPs) were selected in human VGF gene. Transfection of N2a cells with plasmids containing these SNPs revealed no relative change in protein expression levels and normal protein size, except for a truncated protein from the premature stop codon, E525X. All three SNPs resulted in a lower proportion of N2a cells bearing neurites relative to wild-type VGF. Furthermore, all three mutations reduced the total length of dendrites in developing hippocampal neurons. Taken together, our results suggest VGF enhances dendritic maturation and that these effects can be altered by common mutations in the VGF gene. The findings may have implications for people suffering from psychiatric disease or other conditions who may have altered VGF levels.
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Age and Alzheimer's disease gene expression profiles reversed by the glutamate modulator riluzole. Mol Psychiatry 2017; 22:296-305. [PMID: 27021815 PMCID: PMC5042881 DOI: 10.1038/mp.2016.33] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/27/2016] [Accepted: 02/12/2016] [Indexed: 01/21/2023]
Abstract
Alzheimer's disease (AD) and age-related cognitive decline represent a growing health burden and involve the hippocampus, a vulnerable brain region implicated in learning and memory. To understand the molecular effects of aging on the hippocampus, this study characterized the gene expression changes associated with aging in rodents using RNA-sequencing (RNA-seq). The glutamate modulator, riluzole, which was recently shown to improve memory performance in aged rats, prevented many of the hippocampal age-related gene expression changes. A comparison of the effects of riluzole in rats against human AD data sets revealed that many of the gene changes in AD are reversed by riluzole. Expression changes identified by RNA-Seq were validated by qRT-PCR open arrays. Riluzole is known to increase the glutamate transporter EAAT2's ability to scavenge excess glutamate, regulating synaptic transmission. RNA-seq and immunohistochemistry confirmed an increase in EAAT2 expression in hippocampus, identifying a possible mechanism underlying the improved memory function after riluzole treatment.
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Zimering MB, Mirkovic N, Pandya M, Zimering JH, Behnke JA, Thakker-Varia S, Alder J, Donnelly RJ. Toxic Immunoglobulin Light Chain Autoantibodies are Associated with a Cluster of Severe Complications in Older Adult Type 2 Diabetes. JOURNAL OF ENDOCRINOLOGY AND DIABETES 2016; 3:10.15226/2374-6890/3/1/00141. [PMID: 29796423 PMCID: PMC5963888 DOI: 10.15226/2374-6890/3/1/00141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AIMS To assess neuronal depolarization evoked by autoantibodies in diabetic depression compared to depolarization evoked by autoantibodies in control patients. To determine whether a subset of severe (late-onset) diabetic complications may be mediated in part by toxic immunoglobulin light chains that may increase in diabetic nephropathy. METHODS Protein-A eluates from plasma of 21 diabetic depression patients and 37 age-matched controls were tested for depolarization in hippocampal or immature neurons. Subsets of depolarizing or non-depolarizing autoantibodies were tested for neurite outgrowth inhibition in N2A neuroblastoma cells or the ability to modulate Ca2+ release in HL-1 atrial cardiomyocytes or in endothelial cells. The stability of depolarizing autoantibodies was investigated by heat treatment (56°C × 30 minutes) or following prolonged exposure to the pro-protein convertase, furin. Gel filtration of active depolarizing autoantibodies was performed to determine the apparent molecular mass of peak neurotoxicity associated with the autoantibodies. RESULTS Diabetic depression (n = 21) autoantibodies caused significantly greater mean depolarization in neuroblastoma cells (P < 0.01) compared to autoantibodies in diabetic (n = 15) or non-diabetic (n = 11) patients without depression. Depolarizing autoantibodies caused significantly more (P=0.011) inhibition of neurite outgrowth in neuroblastoma cells than non-depolarizing autoantibodies (n = 10) and they evoked sustained, global intracellular Ca2+ release in atrial cardiomyocytes or in endothelial cells. A subset of older diabetic patients suffering with a cluster of nephropathy, non-ischemic cardiomyopathy and/or depression demonstrated the presence of stable light chain dimers having apparent MW of 46 kD and associated with peak neurotoxicity in neuroblastoma cells. CONCLUSION These data suggest that autoantibodies in older adult diabetic depression cause long-lasting depolarization in hippocampal neurons including adult dentate gyrus neural progenitor cells. The autoantibodies may impair adult dentate gyrus neurogenesis associated with treatment-refractory depression via several mechanisms including suppression of neurite outgrowth, and alteration of membrane excitability. Stable, toxic light chain autoantibody components may contribute to a cluster of severe (late-onset) complications characterized by dysfunction in highly vascularized tissues.
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Affiliation(s)
- Mark B. Zimering
- Medical Service (111), Veterans Affairs New Jersey Healthcare System, East Orange & Lyons, NJ, USA
- Division of Endocrinology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - N Mirkovic
- Medical Service (111), Veterans Affairs New Jersey Healthcare System, East Orange & Lyons, NJ, USA
| | - M Pandya
- Medical Service (111), Veterans Affairs New Jersey Healthcare System, East Orange & Lyons, NJ, USA
| | - JH Zimering
- Medical Service (111), Veterans Affairs New Jersey Healthcare System, East Orange & Lyons, NJ, USA
| | - JA Behnke
- Department of Neuroscience and Cell Biology, Rutgers - Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - S Thakker-Varia
- Department of Neuroscience and Cell Biology, Rutgers - Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - J Alder
- Department of Neuroscience and Cell Biology, Rutgers - Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - RJ Donnelly
- Molecular Resource Facility, Rutgers - New Jersey Medical School, Newark, NJ, USA
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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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Chen B, Ma XL, Geng Z, Huang SH, Zhai LK, Guo YY, Chen ZY. Up-regulation of c-Jun NH2-terminal kinase-interacting protein 3 (JIP3) contributes to BDNF-enhanced neurotransmitter release. J Neurochem 2015; 135:453-65. [PMID: 26303065 DOI: 10.1111/jnc.13226] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/29/2015] [Accepted: 06/30/2015] [Indexed: 12/22/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) has been implicated in the potent modulation of synaptic plasticity at both pre-synaptic and post-synaptic sites. However, the molecular mechanism underlying BDNF-mediated pre-synaptic modulation remains incompletely understood. Here, we report that BDNF treatment for over 4 h could significantly enhance the expression of c-Jun NH2-terminal kinase-interacting protein 3 (JIP3) in cultured hippocampal neurons. This enhancement could be blocked by the Trk inhibitor K252a or by a cAMP response element-binding protein (CREB) inhibitor. In addition, chromatin immunoprecipitation (ChIP) assays revealed that CREB could bind with the JIP3 promoter region and the BDNF treatment could increase this binding. Using dual-luciferase assays we further characterized the cAMP response element (CRE) site in the JIP3 promoter. Finally, we found that BDNF-increased JIP3 expression contributes to the BDNF-induced modulation of neurotransmitter release. Together, our studies reveal that in hippocampal neurons BDNF up-regulates JIP3 expression via CREB activation, which contributes to the enhancement of neurotransmitter release; thus, we have identified a novel mechanism that BDNF modulates pre-synaptic transmission.
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Affiliation(s)
- Bing Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong, China.,Department of Pathology Tissue Bank, Qilu Hospital, Shandong University, Jinan, Shandong, China
| | - Xin-Liang Ma
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhao Geng
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Shu-Hong Huang
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Lu-Kai Zhai
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Yun-Yun Guo
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhe-Yu Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, Jinan, Shandong, China
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Shinoda Y, Ahmed S, Ramachandran B, Bharat V, Brockelt D, Altas B, Dean C. BDNF enhances spontaneous and activity-dependent neurotransmitter release at excitatory terminals but not at inhibitory terminals in hippocampal neurons. Front Synaptic Neurosci 2014; 6:27. [PMID: 25426063 PMCID: PMC4226143 DOI: 10.3389/fnsyn.2014.00027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 10/21/2014] [Indexed: 11/30/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is widely reported to enhance synaptic vesicle (SV) exocytosis and neurotransmitter release. But it is still unclear whether BDNF enhances SV recycling at excitatory terminals only, or at both excitatory and inhibitory terminals. In the present study, in a direct comparison using cultured rat hippocampal neurons, we demonstrate that BDNF enhances both spontaneous and activity-dependent neurotransmitter release from excitatory terminals, but not from inhibitory terminals. BDNF treatment for 5 min or 48 h increased both spontaneous and activity-induced anti-synaptotagmin1 (SYT1) antibody uptake at excitatory terminals marked with vGluT1. Conversely, BDNF treatment did not enhance spontaneous or activity-induced uptake of anti-SYT1 antibodies in inhibitory terminals marked with vGAT. Time-lapse imaging of FM1-43 dye destaining in excitatory and inhibitory terminals visualized by post-hoc immunostaining of vGluT1 and vGAT also showed the same result: The rate of spontaneous and activity-induced destaining was increased by BDNF at excitatory synapses, but not at inhibitory synapses. These data demonstrate that BDNF enhances SV exocytosis in excitatory but not inhibitory terminals. Moreover, BDNF enhanced evoked SV exocytosis, even if vesicles were loaded under spontaneous vesicle recycling conditions. Thus, BDNF enhances both spontaneous and activity-dependent neurotransmitter release on both short and long time-scales, by the same mechanism.
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Affiliation(s)
- Yo Shinoda
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany ; Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science Chiba, Japan
| | - Saheeb Ahmed
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Binu Ramachandran
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Vinita Bharat
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - David Brockelt
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Bekir Altas
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Camin Dean
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
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The neuronal activity-driven transcriptome. Mol Neurobiol 2014; 51:1071-88. [PMID: 24935719 DOI: 10.1007/s12035-014-8772-z] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/01/2014] [Indexed: 10/25/2022]
Abstract
Activity-driven transcription is a key event associated with long-lasting forms of neuronal plasticity. Despite the efforts to investigate the regulatory mechanisms that control this complex process and the important advances in the knowledge of the function of many activity-induced genes in neurons, as well as the specific contribution of activity-regulated transcription factors, our understanding of how activity-driven transcription operates at the systems biology level is still very limited. This review focuses on the research of neuronal activity-driven transcription from an "omics" perspective. We will discuss the different high-throughput approaches undertaken to characterize the gene programs downstream of specific activity-regulated transcription factors, including CREB, SRF, MeCP2, Fos, Npas4, and others, and the interplay between epigenetic and transcriptional mechanisms underlying neuronal plasticity changes. Although basic questions remain unanswered and important challenges still lie ahead, the refinement of genome-wide techniques for investigating the neuronal transcriptome and epigenome promises great advances.
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Thakker-Varia S, Behnke J, Doobin D, Dalal V, Thakkar K, Khadim F, Wilson E, Palmieri A, Antila H, Rantamaki T, Alder J. VGF (TLQP-62)-induced neurogenesis targets early phase neural progenitor cells in the adult hippocampus and requires glutamate and BDNF signaling. Stem Cell Res 2014; 12:762-77. [PMID: 24747217 PMCID: PMC4991619 DOI: 10.1016/j.scr.2014.03.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 02/24/2014] [Accepted: 03/18/2014] [Indexed: 01/19/2023] Open
Abstract
The neuropeptide VGF (non-acronymic), which has antidepressant-like effects, enhances adult hippocampal neurogenesis as well as synaptic activity and plasticity in the hippocampus, however the interaction between these processes and the mechanism underlying this regulation remain unclear. In this study, we demonstrate that VGF-derived peptide TLQP-62 specifically enhances the generation of early progenitor cells in nestin-GFP mice. Specifically, TLQP-62 significantly increases the number of Type 2a neural progenitor cells (NPCs) while reducing the number of more differentiated Type 3 cells. The effect of TLQP-62 on proliferation rather than differentiation was confirmed using NPCs in vitro; TLQP-62 but not scrambled peptide PEHN-62 increases proliferation in a cell line as well as in primary progenitors from adult hippocampus. Moreover, TLQP-62 but not scrambled peptide increases Cyclin D mRNA expression. The proliferation of NPCs induced by TLQP-62 requires synaptic activity, in particular through NMDA and metabotropic glutamate receptors. The activation of glutamate receptors by TLQP-62 activation induces phosphorylation of CaMKII through NMDA receptors and protein kinase D through metabotropic glutamate receptor 5 (mGluR5). Furthermore, pharmacological antagonists to CaMKII and PKD inhibit TLQP-62-induced proliferation of NPCs indicating that these signaling molecules downstream of glutamate receptors are essential for the actions of TLQP-62 on neurogenesis. We also show that TLQP-62 gradually activates Brain-Derived Neurotrophic Factor (BDNF)-receptor TrkB in vitro and that Trk signaling is required for TLQP-62-induced proliferation of NPCs. Understanding the precise molecular mechanism of how TLQP-62 influences neurogenesis may reveal mechanisms by which VGF-derived peptides act as antidepressant-like agents.
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Affiliation(s)
- Smita Thakker-Varia
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Joseph Behnke
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - David Doobin
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Vidhi Dalal
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Keya Thakkar
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Farah Khadim
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Elizabeth Wilson
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Alicia Palmieri
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Hanna Antila
- Neuroscience Center, University of Helsinki, P.O. Box 56, Viikinkaari 4, 00014 Helsinki, Finland.
| | - Tomi Rantamaki
- Neuroscience Center, University of Helsinki, P.O. Box 56, Viikinkaari 4, 00014 Helsinki, Finland.
| | - Janet Alder
- Department of Neuroscience and Cell Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
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Alder J, Kallman S, Palmieri A, Khadim F, Ayer JJ, Kumar S, Tsung K, Grinberg I, Thakker-Varia S. Neuropeptide orphanin FQ inhibits dendritic morphogenesis through activation of RhoA. Dev Neurobiol 2013; 73:769-84. [PMID: 23821558 DOI: 10.1002/dneu.22101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 06/20/2013] [Accepted: 06/21/2013] [Indexed: 12/18/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) plays a facilitatory role in neuronal development and promotion of differentiation. Mechanisms that oppose BDNF's stimulatory effects create balance and regulate dendritic growth. However, these mechanisms have not been studied. We have focused our studies on the BDNF-induced neuropeptide OrphaninFQ/ Nociceptin (OFQ); while BDNF is known to enhance synaptic activity, OFQ has opposite effects on activity, learning, and memory. We have now examined whether OFQ provides a balance to the stimulatory effects of BDNF on neuronal differentiation in the hippocampus. Golgi staining in OFQ knockout (KO) mice revealed an increase in primary dendrite length as well as spine density, suggesting that endogenous OFQ inhibits dendritic morphology. We have also used cultured hippocampal neurons to demonstrate that exogenous OFQ has an inhibitory effect on dendritic growth and that the neuropeptide alters the response to BDNF when pre-administered. To determine if BDNF and OFQ act in a feedback loop, we inhibited the actions of the BDNF and OFQ receptors, TrkB and NOP using ANA-12 and NOP KO mice respectively but our data suggest that the two factors do not act in a negative feedback loop. We found that the inhibition of dendritic morphology induced by OFQ is via enhanced RhoA activity. Finally, we have evidence that RhoA activation is required for the inhibitory effects of OFQ on dendritic morphology. Our results reveal basic mechanisms by which neurons not only regulate the formation of proper dendritic growth during development but also control plasticity in the mature nervous system.
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Affiliation(s)
- Janet Alder
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey
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Wairkar YP, Trivedi D, Natarajan R, Barnes K, Dolores L, Cho P. CK2α regulates the transcription of BRP in Drosophila. Dev Biol 2013; 384:53-64. [PMID: 24080510 DOI: 10.1016/j.ydbio.2013.09.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 01/26/2023]
Abstract
Development and plasticity of synapses are brought about by a complex interplay between various signaling pathways. Typically, either changing the number of synapses or strengthening an existing synapse can lead to changes during synaptic plasticity. Altering the machinery that governs the exocytosis of synaptic vesicles, which primarily fuse at specialized structures known as active zones on the presynaptic terminal, brings about these changes. Although signaling pathways that regulate the synaptic plasticity from the postsynaptic compartments are well defined, the pathways that control these changes presynaptically are poorly described. In a genetic screen for synapse development in Drosophila, we found that mutations in CK2α lead to an increase in the levels of Bruchpilot (BRP), a scaffolding protein associated with the active zones. Using a combination of genetic and biochemical approaches, we found that the increase in BRP in CK2α mutants is largely due to an increase in the transcription of BRP. Interestingly, the transcripts of other active zone proteins that are important for function of active zones were also increased, while the transcripts from some other synaptic proteins were unchanged. Thus, our data suggest that CK2α might be important in regulating synaptic plasticity by modulating the transcription of BRP. Hence, we propose that CK2α is a novel regulator of the active zone protein, BRP, in Drosophila.
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Affiliation(s)
- Yogesh P Wairkar
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd., Rte#1045, Galveston, TX 77555, United States.
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Sandhya VK, Raju R, Verma R, Advani J, Sharma R, Radhakrishnan A, Nanjappa V, Narayana J, Somani BL, Mukherjee KK, Pandey A, Christopher R, Prasad TSK. A network map of BDNF/TRKB and BDNF/p75NTR signaling system. J Cell Commun Signal 2013; 7:301-7. [PMID: 23606317 DOI: 10.1007/s12079-013-0200-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/09/2013] [Indexed: 01/15/2023] Open
Affiliation(s)
- Varot K Sandhya
- Institute of Bioinformatics, International Tech Park, Whitefield, Bangalore, 560066, India,
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21
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Leal G, Comprido D, Duarte CB. BDNF-induced local protein synthesis and synaptic plasticity. Neuropharmacology 2013; 76 Pt C:639-56. [PMID: 23602987 DOI: 10.1016/j.neuropharm.2013.04.005] [Citation(s) in RCA: 425] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/25/2013] [Accepted: 04/03/2013] [Indexed: 12/16/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is an important regulator of synaptic transmission and long-term potentiation (LTP) in the hippocampus and in other brain regions, playing a role in the formation of certain forms of memory. The effects of BDNF in LTP are mediated by TrkB (tropomyosin-related kinase B) receptors, which are known to be coupled to the activation of the Ras/ERK, phosphatidylinositol 3-kinase/Akt and phospholipase C-γ (PLC-γ) pathways. The role of BDNF in LTP is best studied in the hippocampus, where the neurotrophin acts at pre- and post-synaptic levels. Recent studies have shown that BDNF regulates the transport of mRNAs along dendrites and their translation at the synapse, by modulating the initiation and elongation phases of protein synthesis, and by acting on specific miRNAs. Furthermore, the effect of BDNF on transcription regulation may further contribute to long-term changes in the synaptic proteome. In this review we discuss the recent progress in understanding the mechanisms contributing to the short- and long-term regulation of the synaptic proteome by BDNF, and the role in synaptic plasticity, which is likely to influence learning and memory formation. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.
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Affiliation(s)
- Graciano Leal
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
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Abstract
Brain-derived neurotrophic factor (BDNF)--a member of a small family of secreted proteins that includes nerve growth factor, neurotrophin 3 and neurotrophin 4--has emerged as a key regulator of neural circuit development and function. The expression, secretion and actions of BDNF are directly controlled by neural activity, and secreted BDNF is capable of mediating many activity-dependent processes in the mammalian brain, including neuronal differentiation and growth, synapse formation and plasticity, and higher cognitive functions. This Review summarizes some of the recent progress in understanding the cellular and molecular mechanisms underlying neurotrophin regulation of neural circuits. The focus of the article is on BDNF, as this is the most widely expressed and studied neurotrophin in the mammalian brain.
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Alder J, Kramer BC, Hoskin C, Thakker-Varia S. Brain-derived neurotrophic factor produced by human umbilical tissue-derived cells is required for its effect on hippocampal dendritic differentiation. Dev Neurobiol 2012; 72:755-65. [DOI: 10.1002/dneu.20980] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Wolstenholme JT, Warner JA, Capparuccini MI, Archer KJ, Shelton KL, Miles MF. Genomic analysis of individual differences in ethanol drinking: evidence for non-genetic factors in C57BL/6 mice. PLoS One 2011; 6:e21100. [PMID: 21698166 PMCID: PMC3116881 DOI: 10.1371/journal.pone.0021100] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 05/20/2011] [Indexed: 01/26/2023] Open
Abstract
Genetic analysis of factors affecting risk to develop excessive ethanol drinking has been extensively studied in humans and animal models for over 20 years. However, little progress has been made in determining molecular mechanisms underlying environmental or non-genetic events contributing to variation in ethanol drinking. Here, we identify persistent and substantial variation in ethanol drinking behavior within an inbred mouse strain and utilize this model to identify gene networks influencing such “non-genetic” variation in ethanol intake. C57BL/6NCrl mice showed persistent inter-individual variation of ethanol intake in a two-bottle choice paradigm over a three-week period, ranging from less than 1 g/kg to over 14 g/kg ethanol in an 18 h interval. Differences in sweet or bitter taste susceptibility or litter effects did not appreciably correlate with ethanol intake variation. Whole genome microarray expression analysis in nucleus accumbens, prefrontal cortex and ventral midbrain region of individual animals identified gene expression patterns correlated with ethanol intake. Results included several gene networks previously implicated in ethanol behaviors, such as glutamate signaling, BDNF and genes involved in synaptic vesicle function. Additionally, genes functioning in epigenetic chromatin or DNA modifications such as acetylation and/or methylation also had expression patterns correlated with ethanol intake. In verification for the significance of the expression findings, we found that a histone deacetylase inhibitor, trichostatin A, caused an increase in 2-bottle ethanol intake. Our results thus implicate specific brain regional gene networks, including chromatin modification factors, as potentially important mechanisms underlying individual variation in ethanol intake.
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Affiliation(s)
- Jennifer T. Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jon A. Warner
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Maria I. Capparuccini
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kellie J. Archer
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Keith L. Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Michael F. Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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25
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Blaveri E, Kelly F, Mallei A, Harris K, Taylor A, Reid J, Razzoli M, Carboni L, Piubelli C, Musazzi L, Racagni G, Mathé A, Popoli M, Domenici E, Bates S. Expression profiling of a genetic animal model of depression reveals novel molecular pathways underlying depressive-like behaviours. PLoS One 2010; 5:e12596. [PMID: 20830301 PMCID: PMC2935375 DOI: 10.1371/journal.pone.0012596] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Accepted: 08/04/2010] [Indexed: 12/29/2022] Open
Abstract
Background The Flinders model is a validated genetic rat model of depression that exhibits a number of behavioural, neurochemical and pharmacological features consistent with those observed in human depression. Principal Findings In this study we have used genome-wide microarray expression profiling of the hippocampus and prefrontal/frontal cortex of Flinders Depression Sensitive (FSL) and control Flinders Depression Resistant (FRL) lines to understand molecular basis for the differences between the two lines. We profiled two independent cohorts of Flinders animals derived from the same colony six months apart, each cohort statistically powered to allow independent as well as combined analysis. Using this approach, we were able to validate using real-time-PCR a core set of gene expression differences that showed statistical significance in each of the temporally distinct cohorts, representing consistently maintained features of the model. Small but statistically significant increases were confirmed for cholinergic (chrm2, chrna7) and serotonergic receptors (Htr1a, Htr2a) in FSL rats consistent with known neurochemical changes in the model. Much larger gene changes were validated in a number of novel genes as exemplified by TMEM176A, which showed 35-fold enrichment in the cortex and 30-fold enrichment in hippocampus of FRL animals relative to FSL. Conclusions These data provide significant insights into the molecular differences underlying the Flinders model, and have potential relevance to broader depression research.
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Affiliation(s)
| | - Fiona Kelly
- Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Alessandra Mallei
- Center of Neuropharmacology-Department of Pharmacological Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milan, Milan, Italy
| | - Kriss Harris
- Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Adam Taylor
- Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Juliet Reid
- Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
| | - Maria Razzoli
- Neurosciences CEDD, GlaxoSmithKline Medicines Research Centre, Verona, Italy
| | - Lucia Carboni
- Neurosciences CEDD, GlaxoSmithKline Medicines Research Centre, Verona, Italy
| | - Chiara Piubelli
- Neurosciences CEDD, GlaxoSmithKline Medicines Research Centre, Verona, Italy
| | - Laura Musazzi
- Center of Neuropharmacology-Department of Pharmacological Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milan, Milan, Italy
| | - Girogio Racagni
- Center of Neuropharmacology-Department of Pharmacological Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milan, Milan, Italy
- Neurosciences CEDD, GlaxoSmithKline Medicines Research Centre, Verona, Italy
- Clinical Neuroscience–Psychiatry, Karolinska Insitutet, Huddinge Hospital, Stockholm, Sweden
- Instituto Di Ricoverio e Cura a Carattere Scientifico, San Giovanni di Dio-Fatebenefratelli, Brescia, Italy
| | - Aleksander Mathé
- Clinical Neuroscience–Psychiatry, Karolinska Insitutet, Huddinge Hospital, Stockholm, Sweden
| | - Maurizio Popoli
- Center of Neuropharmacology-Department of Pharmacological Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milan, Milan, Italy
| | - Enrico Domenici
- Neurosciences CEDD, GlaxoSmithKline Medicines Research Centre, Verona, Italy
| | - Stewart Bates
- Medicines Research Centre, GlaxoSmithKline, Stevenage, United Kingdom
- * E-mail:
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Li Y, Calfa G, Inoue T, Amaral MD, Pozzo-Miller L. Activity-dependent release of endogenous BDNF from mossy fibers evokes a TRPC3 current and Ca2+ elevations in CA3 pyramidal neurons. J Neurophysiol 2010; 103:2846-56. [PMID: 20220070 PMCID: PMC2867575 DOI: 10.1152/jn.01140.2009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 03/08/2010] [Indexed: 01/08/2023] Open
Abstract
Multiple studies have demonstrated that brain-derived neurotrophic factor (BDNF) is a potent modulator of neuronal structure and function in the hippocampus. However, the majority of studies to date have relied on the application of recombinant BDNF. We herein report that endogenous BDNF, released via theta burst stimulation of mossy fibers (MF), elicits a slowly developing cationic current and intracellular Ca(2+) elevations in CA3 pyramidal neurons with the same pharmacological profile of the transient receptor potential canonical 3 (TRPC3)-mediated I(BDNF) activated in CA1 neurons by brief localized applications of recombinant BDNF. Indeed, sensitivity to both the extracellular BDNF scavenger tropomyosin-related kinase B (TrkB)-IgG and small hairpin interference RNA-mediated TRPC3 channel knockdown confirms the identity of this conductance as such, henceforth-denoted MF-I(BDNF). Consistent with such activity-dependent release of BDNF, these MF-I(BDNF) responses were insensitive to manipulations of extracellular Zn(2+) concentration. Brief theta burst stimulation of MFs induced a long-lasting depression in the amplitude of excitatory postsynaptic currents (EPSCs) mediated by both AMPA and N-methyl-d-aspartate (NMDA) receptors without changes in the NMDA receptor/AMPA receptor ratio, suggesting a reduction in neurotransmitter release. This depression of NMDAR-mediated EPSCs required activity-dependent release of endogenous BDNF from MFs and activation of Trk receptors, as it was sensitive to the extracellular BDNF scavenger TrkB-IgG and the tyrosine kinase inhibitor k-252b. These results uncovered the most immediate response to endogenously released--native--BDNF in hippocampal neurons and lend further credence to the relevance of BDNF signaling for synaptic function in the hippocampus.
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Affiliation(s)
- Yong Li
- Department of Neurobiology, Evelyn McKnight Brain Institute, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL 35294-2182, USA
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27
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BDNF signaling in the formation, maturation and plasticity of glutamatergic and GABAergic synapses. Exp Brain Res 2009; 199:203-34. [PMID: 19777221 DOI: 10.1007/s00221-009-1994-z] [Citation(s) in RCA: 221] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 08/12/2009] [Indexed: 01/17/2023]
Abstract
In the past 15 years numerous reports provided strong evidence that brain-derived neurotrophic factor (BDNF) is one of the most important modulators of glutamatergic and GABAergic synapses. Remarkable progress regarding localization, kinetics, and molecular mechanisms of BDNF secretion has been achieved, and a large number of studies provided evidence that continuous extracellular supply of BDNF is important for the proper formation and functional maturation of glutamatergic and GABAergic synapses. BDNF can play a permissive role in shaping synaptic networks, making them more susceptible for the occurrence of plastic changes. In addition, BDNF appears to be also an instructive factor for activity-dependent long-term synaptic plasticity. BDNF release just in response to synaptic stimulation might be a molecular trigger to convert high-frequency synaptic activity into long-term synaptic memories. This review attempts to summarize the current knowledge in synaptic secretion and synaptic action of BDNF, including both permissive and instructive effects of BDNF in synaptic plasticity.
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Zimering MB, Alder J, Thakker-Varia S. Neurotrophic effects of fibroblast growth factor-like autoantibodies in serum from three patients with breast cancer. Brain Res 2009; 1251:276-86. [PMID: 19059221 DOI: 10.1016/j.brainres.2008.11.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 11/04/2008] [Accepted: 11/05/2008] [Indexed: 11/29/2022]
Abstract
Basic fibroblast growth factor (FGF) promotes branching neuritogenesis and survival in rat hippocampal neurons in vitro. Basic FGF is a broad spectrum mitogen which does not normally circulate, but increases in serum from a variety of cancers. In prior work, we described spontaneously-occurring fibroblast growth factor-like autoantibodies in serum from a subset of breast cancer patients with neurological complications. The FGF-like autoantibodies mimicked the potent endothelial cell growth-promoting activity of bFGF yet had remarkably increased stability (activity survived storage at 0-4 degrees C for up to 5 years). In the present study we tested whether FGF-like autoantibodies from breast cancer sera is neurotrophic or neuroprotective. We now report that FGF-like autoantibodies (2-3 microg/mL) from breast cancer sera promoted neuritogenesis in DIV 12 embryonic day 18 rat hippocampal neurons and neurite extension in undifferentiated rat pheochromocytoma PC12 cells. The FGF-like autoantibodies from a breast cancer patient with lupus were unique in protecting rat hippocampal neurons from glutamate-induced cell loss and promoting long-lasting neurite extension and survival in PC-12 cells (up to 25 days in vitro). Breast cancer sera FGF-like autoantibodies induced large sustained increases in inward cationic current associated with depolarization in hippocampal neurons that exceeded the electrophysiological effects of substantial concentrations of basic FGF. These results suggest that differences in potency or other unknown factors contribute to whether subsets of FGF-like autoantibodies from breast cancer sera exhibit long-lasting neurotrophic and neuroprotective effects or an early neurotrophic effect followed by accelerated late neuron death.
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Affiliation(s)
- Mark B Zimering
- Medical Service, Department of Veterans Affairs New Jersey Health Care System, Lyons, NJ 07939, USA.
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Leitch B, Shevtsova O, Kerr JR. Selective reduction in synaptic proteins involved in vesicle docking and signalling at synapses in the ataxic mutant mouse stargazer. J Comp Neurol 2009; 512:52-73. [PMID: 18972569 DOI: 10.1002/cne.21890] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The spontaneous recessive mutant mouse stargazer has a specific and pronounced deficit in brain-derived neurotrophic factor (BDNF) mRNA expression in the cerebellum. Cerebellar granule cells, in particular, show a selective and near-total loss of BDNF. The mutation involves a defect in the calcium channel subunit Cacng2. This severely reduces expression of stargazin. A stargazin-induced failure in BDNF expression is thought to underlie the cerebellar ataxia with which the mutant presents. BDNF is known to regulate plasticity at cerebellar synapses. However, relatively little is known about the mechanism involved. We previously demonstrated that the stargazer mutation affects the phenotype of cerebellar glutamatergic neurons. Stargazer neurons have less glutamate and proportionally fewer docked vesicles at presynaptic sites than controls. In the current study, we investigate the mechanism underlying BDNF-induced synaptic changes by analyzing alterations in synaptic signalling proteins in the stargazer cerebellum. Expression levels of synaptic proteins were evaluated by measuring relative density of immunogold label over granule cell terminals in ultrathin sections from ataxic stargazer mutants compared with matched nonataxic littermates. We show that there is a selective and marked depletion in the levels of vesicle-associated proteins (synaptobrevin, synaptophysin, synaptotagmin, and Rab3a) but not of plasma membrane-associated protein (SNAP-25) in the terminals of the BDNF-deficient granule cells. Changes are restricted to the cerebellum; levels in the hippocampus are unaltered. These data suggest that the BDNF deficits in the cerebellum of stargazer affect synaptic vesicle docking by selectively altering synaptic-protein distribution and abundance.
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Affiliation(s)
- Beulah Leitch
- Department of Anatomy and Structural Biology, Otago School of Medical Sciences, University of Otago, Dunedin, 9054 New Zealand.
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Thakker-Varia S, Alder J. Neuropeptides in depression: role of VGF. Behav Brain Res 2008; 197:262-78. [PMID: 18983874 DOI: 10.1016/j.bbr.2008.10.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Accepted: 10/05/2008] [Indexed: 12/20/2022]
Abstract
The monoamine hypothesis of depression is increasingly called into question by newer theories that revolve around changes in neuronal plasticity, primarily in the hippocampus, at both the structural and the functional levels. Chronic stress negatively regulates hippocampal function while antidepressants ameliorate the effects of stress on neuronal morphology and activity. Both stress and antidepressants have been shown to affect levels of brain-derived neurotrophic factor (BDNF) whose transcription is dependent on cAMP response element binding protein (CREB). BDNF itself has antidepressant-like actions and can induce transcription of a number of molecules. One class of genes regulated by both BDNF and serotonin (5-HT) are neuropeptides including VGF (non-acryonimic) which has a novel role in depression. Neuropeptides are important modulators of neuronal function but their role in affective disorders is just emerging. Recent studies demonstrate that VGF, which is also a CREB-dependent gene, is upregulated by antidepressant drugs and voluntary exercise and is reduced in animal models of depression. VGF enhances hippocampal synaptic plasticity as well as neurogenesis in the dentate gyrus but the mechanisms of antidepressant-like actions of VGF in behavioral paradigms are not known. We summarize experimental data describing the roles of BDNF, VGF and other neuropeptides in depression and how they may be acting through the generation of new neurons and altered synaptic activity. Understanding the molecular and cellular changes that underlie the actions of neuropeptides and how these adaptations result in antidepressant-like effects will aid in developing drugs that target novel pathways for major depressive disorders.
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Affiliation(s)
- Smita Thakker-Varia
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, 683 Hoes Lane West, Robert Wood Johnson-School of Public Health 357A, Piscataway, NJ 08854-5635, United States
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Wang X, Thiagarajan R, Wang Q, Tewolde T, Rich MM, Engisch KL. Regulation of quantal shape by Rab3A: evidence for a fusion pore-dependent mechanism. J Physiol 2008; 586:3949-62. [PMID: 18591190 DOI: 10.1113/jphysiol.2008.151191] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The function of Rab3A, a small GTPase located on synaptic vesicles, is not well understood. Studies in the Rab3A(-/-) mouse support a role in activity-dependent plasticity, but have not reported any effects on spontaneously occurring miniature synaptic currents, except that there is a decrease in resting frequency at the neuromuscular junction. Therefore we were surprised to find an increase in the occurrence of mEPCs with abnormally long half-widths at the neuromuscular junctions of Rab3A(-/-) mice. The abnormal miniature endplate currents (mEPCs), which have significantly greater charge than the average mEPCs for the same fibres, could arise from larger vesicles. However, the type of mEPC most increased in Rab3A(-/-) mice has a slow rise, which suggests it is not the result of full collapse fusion. To test if the slow mEPCs increased after loss of Rab3A could be due to malfunctioning fusion pores, we used carbon fibre amperometry to record pre-spike feet, which have been shown to correspond to the initial opening of a narrow fusion pore, in adrenal chromaffin cells of wild-type and Rab3A(-/-) mice. We found that small amplitude pre-spike feet with abnormally long durations were increased in Rab3A(-/-) cells. The correspondence between mEPC and amperometric data supports our interpretation that slow rising, long half-width mEPCs are caused by reduced diameter fusion pores that remain open longer. These data could be explained by a direct action of Rab3A on the fusion pore, or by Rab3A-dependent control of vesicles with unusual fusion pore characteristics.
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Affiliation(s)
- Xueyong Wang
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
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Simsek-Duran F, Lonart G. The role of RIM1alpha in BDNF-enhanced glutamate release. Neuropharmacology 2008; 55:27-34. [PMID: 18499195 DOI: 10.1016/j.neuropharm.2008.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2007] [Revised: 03/14/2008] [Accepted: 04/11/2008] [Indexed: 11/30/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is known to activate proline-directed Ser/Thr protein kinases and to enhance glutamatergic transmission via a Rab3a-dependent molecular pathway. The identity of molecular targets in BDNF's action on Rab3a pathway, a synaptic vesicle protein involved in vesicle trafficking and synaptic plasticity, is not fully known. Here we demonstrate that BDNF enhances depolarization-evoked efflux of [(3)H]-glutamate from nerve terminals isolated from the CA1 region of the hippocampus. BDNF also potentiated hyperosmotic shock-evoked [(3)H]-glutamate efflux, indicating an effect on the size of the readily releasable pool. This effect of BDNF was completely abolished in nerve terminals derived from Rim1alphaKO (Rab3 interacting molecule 1alpha null mutant) mice. Using in vitro phosphorylation assays we identified two novel phosphorylation sites, Ser447 and Ser745 that were substrates for ERK2, a proline-directed kinase known to be activated by BDNF. The pSer447 site was phosphorylated under resting conditions in hippocampal CA1 nerve terminals and its phosphorylation was enhanced by BDNF treatment, as indicated by the use of a pSer447-RIM1alpha antibody we have developed. Together these findings identify RIM1alpha, a component of the Rab3a molecular pathway in mediating presynaptic plasticity, as a necessary factor in BDNF's enhancement of [(3)H]-glutamate efflux from hippocampal CA1 nerve terminals and indicate a possible role for RIM1alpha phosphorylation in BDNF-dependent presynaptic plasticity.
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Affiliation(s)
- Fatma Simsek-Duran
- Department of Pathology and Anatomy, Eastern Virginia Medical School, 700 W. Olney Road Norfolk, VA 23507, USA
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33
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Kalueff AV. Neurobiology of memory and anxiety: from genes to behavior. Neural Plast 2007; 2007:78171. [PMID: 17502911 PMCID: PMC1847471 DOI: 10.1155/2007/78171] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 11/15/2006] [Accepted: 11/16/2006] [Indexed: 01/18/2023] Open
Abstract
Interaction of anxiety and memory represents an essential feature of CNS functioning. This paper reviews experimental data coming from neurogenetics, neurochemistry, and behavioral pharmacology (as well as parallel clinical findings) reflecting different mechanisms of memory-anxiety interplay, including brain neurochemistry, circuitry, pharmacology, neuroplasticity, genes, and gene-environment interactions. It emphasizes the complexity and nonlinearity of such interplay, illustrated by a survey of anxiety and learning/memory phenotypes in various genetically modified mouse models that exhibit either synergistic or reciprocal effects of the mutation on anxiety levels and memory performance. The paper also assesses the putative role of different neurotransmitter systems and neuropeptides in the regulation of memory processes and anxiety, and discusses the role of neural plasticity in these mechanisms.
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Affiliation(s)
- Allan V Kalueff
- Laboratory of Clinical Science, Division of Intramural Research Program, National Institute of Mental Health , Bethesda, MD 20892-1264, USA.
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Abstract
Since the discovery of nerve growth factor (NGF) in the 1950s and brain-derived neurotrophic factor (BDNF) in the 1980s, a great deal of evidence has mounted for the roles of neurotrophins (NGF; BDNF; neurotrophin-3, NT-3; and neurotrophin-4/5, NT-4/5) in development, physiology, and pathology. BDNF in particular has important roles in neural development and cell survival, as well as appearing essential to molecular mechanisms of synaptic plasticity and larger scale structural rearrangements of axons and dendrites. Basic activity-related changes in the central nervous system (CNS) are thought to depend on BDNF modulation of synaptic transmission. Pathologic levels of BDNF-dependent synaptic plasticity may contribute to conditions such as epilepsy and chronic pain sensitization, whereas application of the trophic properties of BDNF may lead to novel therapeutic options in neurodegenerative diseases and perhaps even in neuropsychiatric disorders. In this chapter, I review neurotrophin structure, signal transduction mechanisms, localization and regulation within the nervous system, and various potential roles in disease. Modulation of neurotrophin action holds significant potential for novel therapies for a variety of neurological and psychiatric disorders.
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Affiliation(s)
- Devin K Binder
- Department of Neurological Surgery, University of California, Irvine, CA 92868, USA.
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Sun Y, Zhang F, Gao J, Gao X, Guo T, Shi Y, Tang W, Li S, Zheng Z, Zheng Y, Li X, Feng G, He L. Variants in the RAB3A gene are not associated with mental retardation in the Chinese population. Neurosci Lett 2006; 401:114-8. [PMID: 16584842 DOI: 10.1016/j.neulet.2006.02.079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2005] [Revised: 02/28/2006] [Accepted: 02/28/2006] [Indexed: 10/24/2022]
Abstract
Mental retardation is a common form of cognitive impairment among children. The underlying causes of mental retardation are extremely heterogeneous, and include significant genetic factors. The coexistence of neuropathology and cognitive deficits supports the view that mental retardation is a disorder of brain development and plasticity. Rab3A, a member of the Rab small G protein family, is a key molecule in modulating basal neurotransmission and contributes to synaptic plasticity. The RAB3A gene is located on chromosome 19p13.11, near a region shown by a linkage study to be involved in the etiology of mental retardation. Because of both its function and chromosomal location, RAB3A is a potential candidate susceptibility gene for mental retardation. To investigate the possible genetic contribution of the RAB3A gene, we performed a case-control association study focused on the Han population of northwestern China using four common SNPs in the gene (rs7259012, rs17683539, rs2271882, and rs874628). Pairwise linkage disequilibrium analysis showed that the four SNPs were in linkage disequilibrium. However, there were no significant differences of either allele or genotype frequencies at any of the SNPs nor any significant differences in haplotype distributions between cases and controls. In conclusion, we have found no evidence for RAB3A conferring susceptibility on mental retardation in the Han Chinese population.
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Affiliation(s)
- Yun Sun
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Taiyuan Road, Shanghai 200031, China
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Wibrand K, Messaoudi E, Håvik B, Steenslid V, Løvlie R, Steen VM, Bramham CR. Identification of genes co-upregulated with Arc during BDNF-induced long-term potentiation in adult rat dentate gyrus in vivo. Eur J Neurosci 2006; 23:1501-11. [PMID: 16553613 DOI: 10.1111/j.1460-9568.2006.04687.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is a critical regulator of transcription-dependent adaptive neuronal responses, such as long-term potentiation (LTP). Brief infusion of BDNF into the dentate gyrus of adult anesthetized rats triggers stable LTP at medial perforant path-granule synapses that is transcription-dependent and requires induction of the immediate early gene Arc. Rather than acting alone, Arc is likely to be part of a larger BDNF-induced transcriptional program. Here, we used cDNA microarray expression profiling to search for genes co-upregulated with Arc 3 h after BDNF-LTP induction. Of nine cDNAs encoding for known genes and up-regulated more than four-fold, we selected five genes, Narp, neuritin, ADP-ribosylation factor-like protein-4 (ARL4L), TGF-beta-induced immediate early gene-1 (TIEG1) and CARP, for further validation. Real-time PCR confirmed robust up-regulation of these genes in an independent set of BDNF-LTP experiments, whereas infusion of the control protein cytochrome C had no effect. In situ hybridization histochemistry further revealed up-regulation of all five genes in somata of post-synaptic granule cells following both BDNF-LTP and high-frequency stimulation-induced LTP. While Arc synthesis is critical for local actin polymerization and stable LTP formation, several of the co-upregulated genes have known functions in excitatory synaptogenesis, axon guidance and glutamate receptor clustering. These results provide novel insight into gene expression responses underlying BDNF-induced synaptic consolidation in the adult brain in vivo.
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Affiliation(s)
- Karin Wibrand
- Department of Biomedicine and Bergen Mental Health Research Center, Section for Physiology, University of Bergen, Jonas Liens vei 91, N-5009 Bergen, Norway
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Tyler WJ, Zhang XL, Hartman K, Winterer J, Muller W, Stanton PK, Pozzo-Miller L. BDNF increases release probability and the size of a rapidly recycling vesicle pool within rat hippocampal excitatory synapses. J Physiol 2006; 574:787-803. [PMID: 16709633 PMCID: PMC1817733 DOI: 10.1113/jphysiol.2006.111310] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Exerting its actions pre-, post- and peri-synaptically, brain-derived neurotrophic factor (BDNF) is one of the most potent modulators of hippocampal synaptic function. Here, we examined the effects of BDNF on a rapidly recycling pool (RRP) of vesicles within excitatory synapses. First, we estimated vesicular release in hippocampal cultures by performing FM4-64 imaging in terminals impinging on enhanced green fluorescent protein (eGFP)-labelled dendritic spines - a hallmark of excitatory synapses. Consistent with a modulation of the RRP, BDNF increased the evoked destaining rate of FM4-64 only during the initial phase of field stimulation. Multiphoton microscopy in acute hippocampal slices confirmed these observations by selectively imaging the RRP, which was loaded with FM1-43 by hyperosmotic shock. Slices exposed to BDNF showed an increase in the evoked and spontaneous rates of FM1-43 destaining from terminals in CA1 stratum radiatum, mostly representing excitatory terminals of Schaffer collaterals. Variance-mean analysis of evoked EPSCs in CA1 pyramidal neurons further confirmed that release probability is increased in BDNF-treated slices, without changes in the number of independent release sites or average postsynaptic quantal amplitude. Because BDNF was absent during dye loading, imaging, destaining and whole-cell recordings, these results demonstrate that BDNF induces a long-lasting enhancement in the probability of transmitter release at hippocampal excitatory synapses by modulating the RRP. Since the endogenous BDNF scavenger TrkB-IgG prevented the enhancement of FM1-43 destaining rate caused by induction of long-term potentiation in acute hippocampal slices, the modulation of a rapidly recycling vesicle pool may underlie the role of BDNF in hippocampal long-term synaptic plasticity.
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Affiliation(s)
- William J Tyler
- Department of Neurobiology, SHEL-1002, University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294-2182, USA
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Ring RH, Alder J, Fennell M, Kouranova E, Black IB, Thakker-Varia S. Transcriptional profiling of brain-derived-neurotrophic factor-induced neuronal plasticity: a novel role for nociceptin in hippocampal neurite outgrowth. JOURNAL OF NEUROBIOLOGY 2006; 66:361-77. [PMID: 16408296 DOI: 10.1002/neu.20223] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Brain derived neurotrophic factor (BDNF) exhibits a sequence of actions on neurons ranging from acute enhancement of transmission to long-term promotion of neurite outgrowth and synaptogenesis associated with learning and memory. The manifold effects of BDNF on neuronal modifications may be mediated by genomic alterations. We previously found that BDNF treatment acutely increases transcription of the synaptic vesicle protein Rab3A, required for trophin-induced synaptic plasticity, as well as the peptide VGF, which increases during learning. To elucidate comprehensive transcriptional programs associated with short- and long-term BDNF exposure, we now examine mRNA abundance and complexity using Affymetrix GeneChips in cultured hippocampal neurons. Consistent with the modulation of synaptic plasticity, BDNF treatment (3-6 h) induced mRNAs encoding the synapse-associated proteins synaptojanin 2, neuronal pentraxin 1, septin 9, and ryanodine receptor 2. BDNF also induced expression of mRNAs encoding neuropeptides (6-12 h), including prepronociceptin, neuropeptide Y, and secretogranin. To determine whether these neuropeptides induced by BDNF mediate neuronal development, we examined their effects on hippocampal neurons. The four mature peptides derived from post-translational processing of the ppNociceptin propeptide induced the expression of several immediate early genes in hippocampal cultures, indicating neuronal activation. To examine the significance of activation, the effects of nociceptin (orphanin FQ) and nocistatin on neurite outgrowth were examined. Quantitative morphometric analysis revealed that nociceptin significantly increased both average neurite length and average number of neurites per neuron, while nocistatin had no effect on these parameters. These results reveal a novel role for nociceptin and suggest that these neuropeptide systems may contribute to the regulation of neuronal function by BDNF.
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Affiliation(s)
- Robert H Ring
- Wyeth Research, Discovery Neuroscience, CN8000, Princeton, New Jersey 08543, USA
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Bramham CR, Messaoudi E. BDNF function in adult synaptic plasticity: the synaptic consolidation hypothesis. Prog Neurobiol 2005; 76:99-125. [PMID: 16099088 DOI: 10.1016/j.pneurobio.2005.06.003] [Citation(s) in RCA: 849] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 05/09/2005] [Accepted: 06/16/2005] [Indexed: 12/19/2022]
Abstract
Interest in BDNF as an activity-dependent modulator of neuronal structure and function in the adult brain has intensified in recent years. Localization of BDNF-TrkB to glutamate synapses makes this system attractive as a dynamic, activity-dependent regulator of excitatory transmission and plasticity. Despite individual breakthroughs, an integrated understanding of BDNF function in synaptic plasticity is lacking. Here, we attempt to distill current knowledge of the molecular mechanisms and function of BDNF in LTP. BDNF activates distinct mechanisms to regulate the induction, early maintenance, and late maintenance phases of LTP. Evidence from genetic and pharmacological approaches is reviewed and tabulated. The specific contribution of BDNF depends on the stimulus pattern used to induce LTP, which impacts the duration and perhaps the subcellular site of BDNF release. Particular attention is given to the role of BDNF as a trigger for protein synthesis-dependent late phase LTP--a process referred to as synaptic consolidation. Recent experiments suggest that BDNF activates synaptic consolidation through transcription and rapid dendritic trafficking of mRNA encoded by the immediate early gene, Arc. A model is proposed in which BDNF signaling at glutamate synapses drives the translation of newly transported (Arc) and locally stored (i.e., alphaCaMKII) mRNA in dendrites. In this model BDNF tags synapses for mRNA capture, while Arc translation defines a critical window for synaptic consolidation. The biochemical mechanisms by which BDNF regulates local translation are also discussed. Elucidation of these mechanisms should shed light on a range of adaptive brain responses including memory and mood resilience.
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Affiliation(s)
- Clive R Bramham
- Department of Biomedicine, Bergen Mental Health Research Center, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway.
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Pang PT, Lu B. Regulation of late-phase LTP and long-term memory in normal and aging hippocampus: role of secreted proteins tPA and BDNF. Ageing Res Rev 2004; 3:407-30. [PMID: 15541709 DOI: 10.1016/j.arr.2004.07.002] [Citation(s) in RCA: 230] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Accepted: 07/20/2004] [Indexed: 10/26/2022]
Abstract
Long-lasting forms of memory are generally believed to be mediated by protein synthesis-dependent, late-phase long-term potentiation (L-LTP). L-LTP exhibits at least two distinctive characteristics compared with early phase LTP (E-LTP): synaptic growth and requirement of gene transcription and new protein synthesis. In this review, we discuss the cellular and molecular mechanisms underlying the structural and functional changes of hippocampal synapses during L-LTP, in the context of long-term memory. We describe experiments that reveal the critical role of cAMP/protein kinase A and MAP kinase pathways, and the downstream transcription factor CREB. Because transcription-dependent long-term changes are input specific, we also discuss the role of "local protein synthesis" and "synaptic tagging" mechanisms that may confer synapse specificity. We then focus on brain-derived neurotrophic factor (BDNF) and tissue plasminogen activator (tPA), two secreted proteins that have been repeatedly implicated in L-LTP. Biochemical and molecular biology experiments indicate that the expression and secretion of both factors are enhanced by strong tetanic stimulation that induces L-LTP as well as by training in hippocampal-dependent memory tasks. Inhibition of either tPA or BDNF by gene knockout and specific inhibitors results in a significant impairments in L-LTP and long-term memory. Further work will be required to address the relationship between BDNF and tPA in various forms of synaptic plasticity, and the mechanisms by which BDNF/tPA achieves synapse-specific modulation. Finally, we discuss how the aging process affects L-LTP and long-term memory.
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Affiliation(s)
- Petti T Pang
- Section on Neural Development and Plasticity, NICHD, NIH, Building 49, Rm. 6A80, 49 Convent Dr., MSC4480 Bethesda, MD 20892-4480, USA
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Alder J, Thakker-Varia S, Bangasser DA, Kuroiwa M, Plummer MR, Shors TJ, Black IB. Brain-derived neurotrophic factor-induced gene expression reveals novel actions of VGF in hippocampal synaptic plasticity. J Neurosci 2003; 23:10800-8. [PMID: 14645472 PMCID: PMC3374594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
Synaptic strengthening induced by brain-derived neurotrophic factor (BDNF) is associated with learning and is coupled to transcriptional activation. However, identification of the spectrum of genes associated with BDNF-induced synaptic plasticity and the correlation of expression with learning paradigms in vivo has not yet been studied. Transcriptional analysis of BDNF-induced synaptic strengthening in cultured hippocampal neurons revealed increased expression of the immediate early genes (IEGs), c-fos, early growth response gene 1 (EGR1), activity-regulated cytoskeletal-associated protein (Arc) at 20 min, and the secreted peptide VGF (non-acronymic) protein precursor at 3 hr. The induced genes served as prototypes to decipher mechanisms of both BDNF-induced transcription and plasticity. BDNF-mediated gene expression was tyrosine kinase B and mitogen-activated protein kinase-dependent, as demonstrated by pharmacological studies. Single-cell transcriptional analysis of Arc after whole-cell patch-clamp recordings indicated that increased gene expression correlated with enhancement of synaptic transmission by BDNF. Increased expression in vitro predicted elevations in vivo: VGF and the IEGs increased after trace eyeblink conditioning, a hippocampal-dependent learning paradigm. VGF protein was also upregulated by BDNF treatment and was expressed in a punctate manner in dissociated hippocampal neurons. Collectively, these findings suggested that the VGF neuropeptides may regulate synaptic function. We found a novel function for VGF by applying VGF peptides to neurons. C-terminal VGF peptides acutely increased synaptic charge in a dose-dependent manner, whereas N-terminal peptide had no effect. These observations indicate that gene profiling in vitro can reveal new mechanisms of synaptic strengthening associated with learning and memory.
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Affiliation(s)
- Janet Alder
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA
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Williams JM, Guévremont D, Kennard JTT, Mason-Parker SE, Tate WP, Abraham WC. Long-term regulation of N-methyl-D-aspartate receptor subunits and associated synaptic proteins following hippocampal synaptic plasticity. Neuroscience 2003; 118:1003-13. [PMID: 12732245 DOI: 10.1016/s0306-4522(03)00028-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Synaptic plasticity in the dentate gyrus is dependent on activation of the N-methyl-D-aspartate (NMDA)-subtype of glutamate receptors. In this study, we show that synaptic plasticity in turn regulates NMDA receptors, since subunits of the NMDA receptor complex are bidirectionally and independently regulated in the dentate gyrus following activation of perforant synapses in awake animals. Low-frequency stimulation that produced a mild synaptic depression resulted in a decrease in the NMDA receptor subunits NR1 and NR2B 48 h following stimulation. High-frequency stimulation that produced long-term potentiation resulted in an increase in NR1 and NR2B at the same time point. Further investigations revealed that in contrast to NR2B, NR1 levels increased gradually after long-term potentiation induction, reaching a peak level at 48 h, and were insensitive to the competitive NMDA receptor antagonist 3-3(2-carboxypiperazin-4-yl) propyl-1-phosphate. The increased levels of NR1 and NR2B at 48 h were found associated with synaptic membranes and with increased NMDA receptor-associated proteins, postsynaptic density protein 95, neuronal nitric oxide synthase and Ca(2+)/calmodulin-dependent protein kinase II, alpha subunit. These data suggest that the persistence of long-term potentiation is associated with an increase in the number of NMDA receptor complexes, which may be indicative of an increase in synaptic contact area.
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Affiliation(s)
- J M Williams
- Department of Anatomy and Structural Biology, Otago School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
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Weickert CS, Hyde TM, Lipska BK, Herman MM, Weinberger DR, Kleinman JE. Reduced brain-derived neurotrophic factor in prefrontal cortex of patients with schizophrenia. Mol Psychiatry 2003; 8:592-610. [PMID: 12851636 DOI: 10.1038/sj.mp.4001308] [Citation(s) in RCA: 405] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Anatomical and molecular abnormalities of excitatory neurons in the dorsolateral prefrontal cortex (DLPFC) are found in schizophrenia. We hypothesized that brain-derived neurotrophic factor (BDNF), a protein capable of increasing pyramidal neuron spine density and augmenting synaptic efficacy of glutamate, may be abnormally expressed in the DLPFC of patients with schizophrenia. Using an RNase protection assay and Western blotting, we detected a significant reduction in BDNF mRNA (mean=23%) and protein (mean=40%) in the DLPFC of patients with schizophrenia compared to normal individuals. At the cellular level, BDNF mRNA was expressed at varying intensities in pyramidal neurons throughout layers II, III, V, and VI of DLPFC. In patients with schizophrenia; neuronal BDNF expression was decreased in layers III, V and VI. Our study demonstrates a reduction in BDNF production and availability in the DLPFC of schizophrenics, and suggests that intrinsic cortical neurons, afferent neurons, and target neurons may receive less trophic support in this disorder.
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Affiliation(s)
- C S Weickert
- Clinical Brain Disorders Branch, NIMH, IRP, NIH, Bethesda, MD 20892-1385, USA.
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Goggi J, Pullar IA, Carney SL, Bradford HF. Signalling pathways involved in the short-term potentiation of dopamine release by BDNF. Brain Res 2003; 968:156-61. [PMID: 12644273 DOI: 10.1016/s0006-8993(03)02234-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) has been shown to modulate synaptic plasticity in the corpus striatum in vitro by activation of the tyrosine kinase linked receptor, TrkB. However, the signalling pathways that mediate this modulation of plasticity are poorly understood. Three proteins mediating signalling pathways are activated by the binding of BDNF to TrkB: phosphoinositol-3 kinase (PI3K); Ras-MEK and phospholipase C-gamma (PLCgamma). The present study investigates which of these pathways are necessary for BDNF-mediated potentiation of synaptic output of dopamine from slices and synaptosomes of rat corpus striatum. The results indicate that activation of the PI3K and Ras-MEK pathways, but not PLCgamma, are involved. Inhibitors of transcription and translation had no effect on the potentiation of depolarisation-stimulated (15 mM KCl) dopamine release mediated by BDNF.
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Affiliation(s)
- Julian Goggi
- Department of Biochemistry, Imperial College of Science, Technology and Medicine, Imperial College Road, South Kensington, SW7 2AY, London, UK
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Abstract
The neurotrophins (NTs) have recently been shown to elicit pronounced effects on quantal neurotransmitter release at both central and peripheral nervous system synapses. Due to their activity-dependent release, as well as the subcellular localization of both protein and receptor, NTs are ideally suited to modify the strength of neuronal connections by "fine-tuning" synaptic activity through direct actions at presynaptic terminals. Here, using BDNF as a prototypical example, the authors provide an update of recent evidence demonstrating that NTs enhance quantal neurotransmitter release at synapses through presynaptic mechanisms. The authors further propose that a potential target for NT actions at presynaptic terminals is the mechanism by which terminals retrieve synaptic vesicles after exocytosis. Depending on the temporal demands placed on synapses during high-frequency synaptic transmission, synapses may use two alternative modes of synaptic vesicle retrieval, the conventional slow endosomal recycling or a faster rapid retrieval at the active zone, referred to as "kiss-and-run." By modulating Ca2+ microdomains associated with voltage-gated Ca2+ channels at active zones, NTs may elicit a switch from the slow to the fast mode of endocytosis of vesicles at presynaptic terminals during high-frequency synaptic transmission, allowing more reliable information transfer and neuronal signaling in the central nervous system.
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Affiliation(s)
- William J Tyler
- Department of Psychology, Civitan International Research Center. University of Alabama at Birmingham, Birmingham, Alabama 35294-0021, USA
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Abstract
Analysis of single-cell gene expression promises a more precise understanding of human disease pathogenesis and important diagnostic applications. Here, we review the rationale for the study of gene expression at the single-cell level, practical methods to isolate homogeneous or single-cell samples, and current approaches to the analysis of single-cell gene expression. Finally, we highlight applications of laser microdissection-based gene expression analysis to the study of human disease and clinical diagnosis.
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Affiliation(s)
- Randy Todd
- Massachusetts General Hospital, Harvard School of Dental Medicine, 188 Longwood Ave, Boston, MA 02115, USA.
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Douglas CL, Baghdoyan HA, Lydic R. Prefrontal cortex acetylcholine release, EEG slow waves, and spindles are modulated by M2 autoreceptors in C57BL/6J mouse. J Neurophysiol 2002; 87:2817-22. [PMID: 12037184 DOI: 10.1152/jn.2002.87.6.2817] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent evidence suggests that muscarinic cholinergic receptors of the M2 subtype serve as autoreceptors modulating acetylcholine (ACh) release in prefrontal cortex. The potential contribution of M2 autoreceptors to excitability control of prefrontal cortex has not been investigated. The present study tested the hypothesis that M2 autoreceptors contribute to activation of the cortical electroencephalogram (EEG) in C57BL/6J (B6) mouse. This hypothesis was evaluated using microdialysis delivery of the muscarinic antagonist AF-DX116 (3 nM) while simultaneously quantifying ACh release in prefrontal cortex, number of 7- to 14-Hz EEG spindles, and EEG power spectral density. Mean ACh release in prefrontal cortex was significantly increased (P < 0.0002) by AF-DX116. The number of 7- to 14-Hz EEG spindles caused by halothane anesthesia was significantly decreased (P < 0.0001) by dialysis delivery of AF-DX116 to prefrontal cortex. The cholinergically induced cortical activation was characterized by a significant (P < 0.05) decrease in slow-wave EEG power. Together, these neurochemical and EEG data support the conclusion that M2 autoreceptor enhancement of ACh release in prefrontal cortex activates EEG in contralateral prefrontal cortex of B6 mouse. EEG slow-wave activity varies across mouse strains, and the results encourage comparative phenotyping of cortical ACh release and EEG in additional mouse models.
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Affiliation(s)
- Christopher L Douglas
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
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