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Maiti P, Manna J, Ilavazhagan G, Rossignol J, Dunbar GL. Molecular regulation of dendritic spine dynamics and their potential impact on synaptic plasticity and neurological diseases. Neurosci Biobehav Rev 2015; 59:208-37. [PMID: 26562682 DOI: 10.1016/j.neubiorev.2015.09.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 08/20/2015] [Accepted: 09/07/2015] [Indexed: 12/12/2022]
Abstract
The structure and dynamics of dendritic spines reflect the strength of synapses, which are severely affected in different brain diseases. Therefore, understanding the ultra-structure, molecular signaling mechanism(s) regulating dendritic spine dynamics is crucial. Although, since last century, dynamics of spine have been explored by several investigators in different neurological diseases, but despite countless efforts, a comprehensive understanding of the fundamental etiology and molecular signaling pathways involved in spine pathology is lacking. The purpose of this review is to provide a contextual framework of our current understanding of the molecular mechanisms of dendritic spine signaling, as well as their potential impact on different neurodegenerative and psychiatric diseases, as a format for highlighting some commonalities in function, as well as providing a format for new insights and perspectives into this critical area of research. Additionally, the potential strategies to restore spine structure-function in different diseases are also pointed out. Overall, these informations should help researchers to design new drugs to restore the structure-function of dendritic spine, a "hot site" of synaptic plasticity.
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Affiliation(s)
- Panchanan Maiti
- Field Neurosciences Institute, St. Mary's of Michigan, Saginaw, MI, USA; Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA.
| | - Jayeeta Manna
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
| | - G Ilavazhagan
- Hindustan University, Rajiv Gandhi Salai (OMR), Padur, Kelambakam, Chennai, TN, India.
| | - Julien Rossignol
- Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA; College of Medicine, Central Michigan University, Mt. Pleasant, MI, USA.
| | - Gary L Dunbar
- Field Neurosciences Institute, St. Mary's of Michigan, Saginaw, MI, USA; Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA.
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202
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Cuberos H, Vallée B, Vourc'h P, Tastet J, Andres CR, Bénédetti H. Roles of LIM kinases in central nervous system function and dysfunction. FEBS Lett 2015; 589:3795-806. [PMID: 26545494 DOI: 10.1016/j.febslet.2015.10.032] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/21/2015] [Accepted: 10/28/2015] [Indexed: 12/30/2022]
Abstract
LIM kinase 1 (LIMK1) and LIM kinase 2 (LIMK2) regulate actin dynamics by phosphorylating cofilin. In this review, we outline studies that have shown an involvement of LIMKs in neuronal function and we detail some of the pathways and molecular mechanisms involving LIMKs in neurodevelopment and synaptic plasticity. We also review the involvement of LIMKs in neuronal diseases and emphasize the differences in the regulation of LIMKs expression and mode of action. We finally present the existence of a cofilin-independent pathway also involved in neuronal function. A better understanding of the differences between both LIMKs and of the precise molecular mechanisms involved in their mode of action and regulation is now required to improve our understanding of the physiopathology of the neuronal diseases associated with LIMKs.
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Affiliation(s)
- H Cuberos
- CNRS UPR 4301, CBM, Orléans, France; UMR INSERM U930, Université François-Rabelais, Tours, France
| | - B Vallée
- CNRS UPR 4301, CBM, Orléans, France
| | - P Vourc'h
- UMR INSERM U930, Université François-Rabelais, Tours, France; CHRU de Tours, Service de Biochimie et de Biologie Moléculaire, Tours, France
| | - J Tastet
- University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, Netherlands
| | - C R Andres
- UMR INSERM U930, Université François-Rabelais, Tours, France; CHRU de Tours, Service de Biochimie et de Biologie Moléculaire, Tours, France
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203
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Abstract
Both genetic and environmental factors are thought to contribute to neurodevelopmental and neuropsychiatric disorders with maternal immune activation (MIA) being a risk factor for both autism spectrum disorders and schizophrenia. Although MIA mouse offspring exhibit behavioral impairments, the synaptic alterations in vivo that mediate these behaviors are not known. Here we employed in vivo multiphoton imaging to determine that in the cortex of young MIA offspring there is a reduction in number and turnover rates of dendritic spines, sites of majority of excitatory synaptic inputs. Significantly, spine impairments persisted into adulthood and correlated with increased repetitive behavior, an ASD relevant behavioral phenotype. Structural analysis of synaptic inputs revealed a reorganization of presynaptic inputs with a larger proportion of spines being contacted by both excitatory and inhibitory presynaptic terminals. These structural impairments were accompanied by altered excitatory and inhibitory synaptic transmission. Finally, we report that a postnatal treatment of MIA offspring with the anti-inflammatory drug ibudilast, prevented both synaptic and behavioral impairments. Our results suggest that a possible altered inflammatory state associated with maternal immune activation results in impaired synaptic development that persists into adulthood but which can be prevented with early anti-inflammatory treatment.
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204
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Regulation of AMPA receptor subunit GluA1 surface expression by PAK3 phosphorylation. Proc Natl Acad Sci U S A 2015; 112:E5883-90. [PMID: 26460013 DOI: 10.1073/pnas.1518382112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
AMPA receptors (AMPARs) are the major excitatory receptors of the brain and are fundamental to synaptic plasticity, memory, and cognition. Dynamic recycling of AMPARs in neurons is regulated through several types of posttranslational modification, including phosphorylation. Here, we identify a previously unidentified signal transduction cascade that modulates phosphorylation of serine residue 863 (S863) in the GluA1 AMPAR subunit and controls surface trafficking of GluA1 in neurons. Activation of the EphR-Ephrin signal transduction pathway enhances S863 phosphorylation. Further, EphB2 can interact with Zizimin1, a guanine-nucleotide exchange factor that activates Cdc42 and stimulates S863 phosphorylation in neurons. Among the numerous targets downstream of Cdc42, we determined that the p21-activated kinase-3 (PAK3) phosphorylates S863 in vitro. Moreover, specific loss of PAK3 expression and pharmacological inhibition of PAK both disrupt activity-dependent phosphorylation of S863 in cortical neurons. EphB2, Cdc42, and PAKs are broadly capable of controlling dendritic spine formation and synaptic plasticity and are implicated in multiple cognitive disorders. Collectively, these data delineate a novel signal cascade regulating AMPAR trafficking that may contribute to the molecular mechanisms that govern learning and cognition.
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205
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Lesion-induced and activity-dependent structural plasticity of Purkinje cell dendritic spines in cerebellar vermis and hemisphere. Brain Struct Funct 2015; 221:3405-26. [PMID: 26420278 DOI: 10.1007/s00429-015-1109-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 09/09/2015] [Indexed: 10/23/2022]
Abstract
Neuroplasticity allows the brain to encode experience and learn behaviors, and also to re-acquire lost functions after damage. The cerebellum is a suitable structure to address this topic because of its strong involvement in learning processes and compensation of lesion-induced deficits. This study was aimed to characterize the effects of a hemicerebellectomy (HCb) combined or not with the exposition to environmental enrichment (EE) on dendritic spine density and size in Purkinje cell proximal and distal compartments of cerebellar vermian and hemispherical regions. Male Wistar rats were housed in enriched or standard environments from the 21st post-natal day (pnd) onwards. At the 75th pnd, rats were submitted to HCb or sham lesion. Neurological symptoms and spatial performance in the Morris water maze were evaluated. At the end of testing, morphological analyses assessed dendritic spine density, area, length, and head diameter on vermian and hemispherical Purkinje cells. All hemicerebellectomized (HCbed) rats showed motor compensation, but standard-reared HCbed animals exhibited cognitive impairment that was almost completely compensated in enriched HCbed rats. The standard-reared HCbed rats showed decreased density with augmented size of Purkinje cell spines in the vermis, and augmented both density and size in the hemisphere. Enriched HCbed rats almost completely maintained the spine density and size induced by EE. Both lesion-induced and activity-dependent cerebellar plastic changes may be interpreted as "beneficial" brain reactions, aimed to support behavioral performance rescuing.
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206
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Miguez A, García-Díaz Barriga G, Brito V, Straccia M, Giralt A, Ginés S, Canals JM, Alberch J. Fingolimod (FTY720) enhances hippocampal synaptic plasticity and memory in Huntington's disease by preventing p75NTR up-regulation and astrocyte-mediated inflammation. Hum Mol Genet 2015; 24:4958-70. [PMID: 26063761 DOI: 10.1093/hmg/ddv218] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 06/07/2015] [Indexed: 12/20/2022] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disorder characterized by motor and cognitive impairments, involving striatum, cortex and hippocampus. Synaptic and memory dysfunction in HD mouse models have been related to low levels of brain-derived neurotrophic factor (BDNF) and imbalance between TrkB and p75(NTR) receptors. In addition, astrocyte over-activation has also been suggested to contribute to HD cognitive deficits. Fingolimod (FTY720), a modulator of sphingosine-1 phosphate (S1P) receptors, has been shown to increase BDNF levels and to reduce astrogliosis, proving its potential to regulate trophic support and inflammatory response. In this view, we have investigated whether FTY720 improves synaptic plasticity and memory in the R6/1 mouse model of HD, through regulation of BDNF signaling and astroglial reactivity. Chronic administration of FTY720 from pre-symptomatic stages ameliorated long-term memory deficits and dendritic spine loss in CA1 hippocampal neurons from R6/1 mice. Furthermore, FTY720 delivery prevented astrogliosis and over-activation of nuclear factor kappa beta (NF-κB) signaling in the R6/1 hippocampus, reducing tumor necrosis factor alpha (TNFα) and induced nitric oxide synthase (iNOS) levels. TNFα decrease correlated with the normalization of p75(NTR) expression in the hippocampus of FTY720-treated R6/1 mice, thus preventing p75(NTR)/TrkB imbalance. In addition, FTY720 increased cAMP levels and promoted phosphorylation of CREB and RhoA in the hippocampus of R6/1 mice, further supporting its role in the enhancement of synaptic plasticity. Our findings provide new insights into the mechanism of action of FTY720 and reveal a novel therapeutic strategy to treat memory deficits in HD.
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Affiliation(s)
- Andrés Miguez
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Gerardo García-Díaz Barriga
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Verónica Brito
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Marco Straccia
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Albert Giralt
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Silvia Ginés
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Josep M Canals
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Jordi Alberch
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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207
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Intra-Amniotic LPS Induced Region-Specific Changes in Presynaptic Bouton Densities in the Ovine Fetal Brain. BIOMED RESEARCH INTERNATIONAL 2015; 2015:276029. [PMID: 26417592 PMCID: PMC4568354 DOI: 10.1155/2015/276029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 12/14/2014] [Indexed: 11/17/2022]
Abstract
Rationale. Chorioamnionitis has been associated with increased risk for fetal brain damage. Although, it is now accepted that synaptic dysfunction might be responsible for functional deficits, synaptic densities/numbers after a fetal inflammatory challenge have not been studied in different regions yet. Therefore, we tested in this study the hypothesis that LPS-induced chorioamnionitis caused profound changes in synaptic densities in different regions of the fetal sheep brain. Material and Methods. Chorioamnionitis was induced by a 10 mg intra-amniotic LPS injection at two different exposure intervals. The fetal brain was studied at 125 days of gestation (term = 150 days) either 2 (LPS2D group) or 14 days (LPS14D group) after LPS or saline injection (control group). Synaptophysin immunohistochemistry was used to quantify the presynaptic density in layers 2-3 and 5-6 of the motor cortex, somatosensory cortex, entorhinal cortex, and piriforme cortex, in the nucleus caudatus and putamen and in CA1/2, CA3, and dentate gyrus of the hippocampus. Results. There was a significant reduction in presynaptic bouton densities in layers 2-3 and 5-6 of the motor cortex and in layers 2-3 of the entorhinal and the somatosensory cortex, in the nucleus caudate and putamen and the CA1/2 and CA3 of the hippocampus in the LPS2D compared to control animals. Only in the motor cortex and putamen, the presynaptic density was significantly decreased in the LPS14 D compared to the control group. No changes were found in the dentate gyrus of the hippocampus and the piriforme cortex. Conclusion. We demonstrated that LPS-induced chorioamnionitis caused a decreased density in presynaptic boutons in different areas in the fetal brain. These synaptic changes seemed to be region-specific, with some regions being more affected than others, and seemed to be transient in some regions.
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208
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Scheff SW, Price DA, Ansari MA, Roberts KN, Schmitt FA, Ikonomovic MD, Mufson EJ. Synaptic change in the posterior cingulate gyrus in the progression of Alzheimer's disease. J Alzheimers Dis 2015; 43:1073-90. [PMID: 25147118 DOI: 10.3233/jad-141518] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mild cognitive impairment (MCI) is considered to be an early stage in the progression of Alzheimer's disease (AD) providing an opportunity to investigate brain pathogenesis prior to the onset of dementia. Neuroimaging studies have identified the posterior cingulate gyrus (PostC) as a cortical region affected early in the onset of AD. This association cortex is involved in a variety of different cognitive tasks and is intimately connected with the hippocampal/entorhinal cortex region, a component of the medial temporal memory circuit that displays early AD pathology. We quantified the total number of synapses in lamina 3 of the PostC using unbiased stereology coupled with electron microscopy from short postmortem autopsy tissue harvested from cases at different stage of AD progression. Individuals in the early stages of AD showed a significant decline in synaptic numbers compared to individuals with no cognitive impairment (NCI). Subjects with MCI exhibited synaptic numbers that were between the AD and NCI cohorts. Adjacent tissue was evaluated for changes in both pre and postsynaptic proteins levels. Individuals with MCI demonstrated a significant loss in presynaptic markers synapsin-1 and synaptophysin and postsynaptic markers PSD-95 and SAP-97. Levels of [3H]PiB binding was significantly increased in MCI and AD and correlated strongly with levels of synaptic proteins. All synaptic markers showed a significant association with Mini-Mental Status Examination scores. These results support the idea that the PostC synaptic function is affected during the prodromal stage of the disease and may underlie some of the early clinical sequelae associated with AD.
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Affiliation(s)
- Stephen W Scheff
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Douglas A Price
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Mubeen A Ansari
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Kelly N Roberts
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | | | - Milos D Ikonomovic
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA Geriatric Research Educational and Clinical Center, V.A. Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Elliott J Mufson
- Rush University Medical Center, Department of Neurological Sciences, Chicago, IL, USA
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209
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Kessels MM, Qualmann B. Different functional modes of BAR domain proteins in formation and plasticity of mammalian postsynapses. J Cell Sci 2015; 128:3177-85. [PMID: 26285709 DOI: 10.1242/jcs.174193] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
A plethora of cell biological processes involve modulations of cellular membranes. By using extended lipid-binding interfaces, some proteins have the power to shape membranes by attaching to them. Among such membrane shapers, the superfamily of Bin-Amphiphysin-Rvs (BAR) domain proteins has recently taken center stage. Extensive structural work on BAR domains has revealed a common curved fold that can serve as an extended membrane-binding interface to modulate membrane topologies and has allowed the grouping of the BAR domain superfamily into subfamilies with structurally slightly distinct BAR domain subtypes (N-BAR, BAR, F-BAR and I-BAR). Most BAR superfamily members are expressed in the mammalian nervous system. Neurons are elaborately shaped and highly compartmentalized cells. Therefore, analyses of synapse formation and of postsynaptic reorganization processes (synaptic plasticity) - a basis for learning and memory formation - has unveiled important physiological functions of BAR domain superfamily members. These recent advances, furthermore, have revealed that the functions of BAR domain proteins include different aspects. These functions are influenced by the often complex domain organization of BAR domain proteins. In this Commentary, we review these recent insights and propose to classify BAR domain protein functions into (1) membrane shaping, (2) physical integration, (3) action through signaling components, and (4) suppression of other BAR domain functions.
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Affiliation(s)
- Michael M Kessels
- Institute of Biochemistry I, Jena University Hospital/Friedrich-Schiller-University, Nonnenplan 2-4, 07743 Jena, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital/Friedrich-Schiller-University, Nonnenplan 2-4, 07743 Jena, Germany
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210
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Lee CC, Huang CC, Hsu KS. The phospholipid-binding protein SESTD1 negatively regulates dendritic spine density by interfering with Rac1-Trio8 signaling pathway. Sci Rep 2015; 5:13250. [PMID: 26272757 PMCID: PMC4536496 DOI: 10.1038/srep13250] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/22/2015] [Indexed: 11/09/2022] Open
Abstract
Dendritic spines are actin-rich protrusions from neuronal dendrites that harbor the majority of excitatory synapses. The balance of spine formation and retraction may influence dendritic integrity. While knowledge of the molecular mechanisms that promote dendritic spine formation has accumulated, little is known about the factors that limit spine formation. Here, we show that SESTD1, a phospholipid-binding protein containing a lipid-binding SEC14-like domain and two spectrin-repeat cytoskeleton interaction domains, negatively regulates dendritic spine density in cultured hippocampal neurons. Overexpression of SESTD1 decreases dendritic spine density in neurons by interfering with the interaction between Rac1 and its guanine nucleotide exchange factor (GEF) Trio8. Conversely, knockdown of SESTD1 increases dendritic spine density. Further analysis reveals that the SPEC1 domain-mediated interaction with Rac1 is required for SESTD1 activity toward a decrease in dendritic spine density. Transfection of GEF domain of Trio8 into neurons rescues SESTD1-mediated decrease in dendritic spine density. More importantly, overexpression of SESTD1 results in a decrease in the frequency of miniature excitatory postsynaptic currents (mEPSCs), whereas SESTD1 knockdown increases the mEPSC frequency. These results suggest that SESTD1 may act as a negative regulator of the Rac1-Trio8 signaling pathway to reduce dendritic spine density and lower excitatory synaptic transmission in hippocampal neurons.
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Affiliation(s)
- Cheng-Che Lee
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chiung-Chun Huang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Kuei-Sen Hsu
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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211
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Dall'Oglio A, Dutra ACL, Moreira JE, Rasia-Filho AA. The human medial amygdala: structure, diversity, and complexity of dendritic spines. J Anat 2015. [PMID: 26218827 DOI: 10.1111/joa.12358] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The medial nucleus of the amygdala (Me) is a component of the neural circuit for the interpretation of multimodal sensory stimuli and the elaboration of emotions and social behaviors in primates. We studied the presence, distribution, diverse shape, and connectivity of dendritic spines in the human Me of adult postmortem men. Data were obtained from the five types of multipolar neurons found in the Me using an adapted Golgi method and light microscopy, the carbocyanine DiI fluorescent dye and confocal microscopy, and transmission electron microscopy. Three-dimensional reconstruction of spines showed a continuum of shapes and sizes, with the spines either lying isolated or forming clusters. These dendritic spines were classified as stubby/wide, thin, mushroom-like, ramified or with an atypical morphology including intermediate shapes, double spines, and thorny excrescences. Pleomorphic spines were found from proximal to distal dendritic branches suggesting potential differences for synaptic processing, strength, and plasticity in the Me neurons. Furthermore, the human Me has large and thin spines with a gemmule appearance, spinules, and filopodium. The ultrastructural data showed dendritic spines forming monosynaptic or multisynaptic contacts at the spine head and neck, and with asymmetric or symmetric characteristics. Additional findings included en passant, reciprocal, and serial synapses in the Me. Complex long-necked thin spines were observed in this subcortical area. These new data reveal the diversity of the dendritic spines in the human Me likely involved with the integration and processing of local synaptic inputs and with functional implications in physiological and various neuropathological conditions.
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Affiliation(s)
- Aline Dall'Oglio
- Department of Basic Sciences/Physiology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Ana Carolina L Dutra
- Department of Basic Sciences/Physiology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Jorge E Moreira
- Laboratory of Synaptic Structure, Departments of Pathology and Forensic Medicine and Neuroscience and Behavior, Ribeirão Preto School of Medicine, University of São Paulo (FMRP-USP), Ribeirão Preto, Brazil
| | - Alberto A Rasia-Filho
- Department of Basic Sciences/Physiology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, Brazil
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212
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Dorostkar MM, Zou C, Blazquez-Llorca L, Herms J. Analyzing dendritic spine pathology in Alzheimer's disease: problems and opportunities. Acta Neuropathol 2015; 130:1-19. [PMID: 26063233 PMCID: PMC4469300 DOI: 10.1007/s00401-015-1449-5] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/02/2015] [Accepted: 06/02/2015] [Indexed: 12/22/2022]
Abstract
Synaptic failure is an immediate cause of cognitive decline and memory dysfunction in Alzheimer’s disease. Dendritic spines are specialized structures on neuronal processes, on which excitatory synaptic contacts take place and the loss of dendritic spines directly correlates with the loss of synaptic function. Dendritic spines are readily accessible for both in vitro and in vivo experiments and have, therefore, been studied in great detail in Alzheimer’s disease mouse models. To date, a large number of different mechanisms have been proposed to cause dendritic spine dysfunction and loss in Alzheimer’s disease. For instance, amyloid beta fibrils, diffusible oligomers or the intracellular accumulation of amyloid beta have been found to alter the function and structure of dendritic spines by distinct mechanisms. Furthermore, tau hyperphosphorylation and microglia activation, which are thought to be consequences of amyloidosis in Alzheimer’s disease, may also contribute to spine loss. Lastly, genetic and therapeutic interventions employed to model the disease and elucidate its pathogenetic mechanisms in experimental animals may cause alterations of dendritic spines on their own. However, to date none of these mechanisms have been translated into successful therapeutic approaches for the human disease. Here, we critically review the most intensely studied mechanisms of spine loss in Alzheimer’s disease as well as the possible pitfalls inherent in the animal models of such a complex neurodegenerative disorder.
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Affiliation(s)
- Mario M. Dorostkar
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Chengyu Zou
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University Munich, Munich, Germany
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Lidia Blazquez-Llorca
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Jochen Herms
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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213
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Maiti P, Manna J, McDonald MP. Merging advanced technologies with classical methods to uncover dendritic spine dynamics: A hot spot of synaptic plasticity. Neurosci Res 2015; 96:1-13. [DOI: 10.1016/j.neures.2015.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 02/17/2015] [Accepted: 02/19/2015] [Indexed: 01/08/2023]
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214
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Degnan AJ, Wisnowski JL, Choi S, Ceschin R, Bhushan C, Leahy RM, Corby P, Schmithorst VJ, Panigrahy A. Altered Structural and Functional Connectivity in Late Preterm Preadolescence: An Anatomic Seed-Based Study of Resting State Networks Related to the Posteromedial and Lateral Parietal Cortex. PLoS One 2015; 10:e0130686. [PMID: 26098888 PMCID: PMC4476681 DOI: 10.1371/journal.pone.0130686] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 05/22/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Late preterm birth confers increased risk of developmental delay, academic difficulties and social deficits. The late third trimester may represent a critical period of development of neural networks including the default mode network (DMN), which is essential to normal cognition. Our objective is to identify functional and structural connectivity differences in the posteromedial cortex related to late preterm birth. METHODS Thirty-eight preadolescents (ages 9-13; 19 born in the late preterm period (≥32 weeks gestational age) and 19 at term) without access to advanced neonatal care were recruited from a low socioeconomic status community in Brazil. Participants underwent neurocognitive testing, 3-dimensional T1-weighted imaging, diffusion-weighted imaging and resting state functional MRI (RS-fMRI). Seed-based probabilistic diffusion tractography and RS-fMRI analyses were performed using unilateral seeds within the posterior DMN (posterior cingulate cortex, precuneus) and lateral parietal DMN (superior marginal and angular gyri). RESULTS Late preterm children demonstrated increased functional connectivity within the posterior default mode networks and increased anti-correlation with the central-executive network when seeded from the posteromedial cortex (PMC). Key differences were demonstrated between PMC components with increased anti-correlation with the salience network seen only with posterior cingulate cortex seeding but not with precuneus seeding. Probabilistic tractography showed increased streamlines within the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus within late preterm children while decreased intrahemispheric streamlines were also observed. No significant differences in neurocognitive testing were demonstrated between groups. CONCLUSION Late preterm preadolescence is associated with altered functional connectivity from the PMC and lateral parietal cortex to known distributed functional cortical networks despite no significant executive neurocognitive differences. Selective increased structural connectivity was observed in the setting of decreased posterior interhemispheric connections. Future work is needed to determine if these findings represent a compensatory adaptation employing alternate neural circuitry or could reflect subtle pathology resulting in emotional processing deficits not seen with neurocognitive testing.
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Affiliation(s)
- Andrew J. Degnan
- Department of Pediatric Radiology, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Floor 2, Pittsburgh, PA, 15224, United States of America
- Department of Radiology, University of Pittsburgh Medical Center (UPMC), 3950 Presby South Tower, 200 Lothrop Street, Pittsburgh, PA 15213, United States of America
| | - Jessica L. Wisnowski
- Department of Pediatric Radiology, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Floor 2, Pittsburgh, PA, 15224, United States of America
- Brain and Creativity Institute, University of Southern California, 3620A McClintock Avenue, Los Angeles, CA 90089, United States of America
- Department of Radiology, Children’s Hospital Los Angeles, Los Angeles, CA 90027, United States of America
| | - SoYoung Choi
- Brain and Creativity Institute, University of Southern California, 3620A McClintock Avenue, Los Angeles, CA 90089, United States of America
| | - Rafael Ceschin
- Department of Pediatric Radiology, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Floor 2, Pittsburgh, PA, 15224, United States of America
- Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Chitresh Bhushan
- Signal and Image Processing Institute, University of Southern California, Los Angeles, CA 90089, United States of America
| | - Richard M. Leahy
- Signal and Image Processing Institute, University of Southern California, Los Angeles, CA 90089, United States of America
| | - Patricia Corby
- Twins Institute for Genetics Research, Montes Claros, Minas Gerais 39400–115, Brazil
- New York University Bluestone Center for Clinical Research, 421 1st Ave, New York, NY 10010, United States of America
| | - Vincent J. Schmithorst
- Department of Pediatric Radiology, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Floor 2, Pittsburgh, PA, 15224, United States of America
| | - Ashok Panigrahy
- Department of Pediatric Radiology, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Floor 2, Pittsburgh, PA, 15224, United States of America
- Brain and Creativity Institute, University of Southern California, 3620A McClintock Avenue, Los Angeles, CA 90089, United States of America
- Department of Radiology, Children’s Hospital Los Angeles, Los Angeles, CA 90027, United States of America
- Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, PA, United States of America
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Chang EH, Volpe BT, Mackay M, Aranow C, Watson P, Kowal C, Storbeck J, Mattis P, Berlin R, Chen H, Mader S, Huerta TS, Huerta PT, Diamond B. Selective Impairment of Spatial Cognition Caused by Autoantibodies to the N-Methyl-D-Aspartate Receptor. EBioMedicine 2015; 2:755-64. [PMID: 26286205 PMCID: PMC4534689 DOI: 10.1016/j.ebiom.2015.05.027] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 12/13/2022] Open
Abstract
Patients with systemic lupus erythematosus (SLE) experience cognitive abnormalities in multiple domains including processing speed, executive function, and memory. Here we show that SLE patients carrying antibodies that bind DNA and the GluN2A and GluN2B subunits of the N-methyl-d-aspartate receptor (NMDAR), termed DNRAbs, displayed a selective impairment in spatial recall. Neural recordings in a mouse model of SLE, in which circulating DNRAbs penetrate the hippocampus, revealed that CA1 place cells exhibited a significant expansion in place field size. Structural analysis showed that hippocampal pyramidal cells had substantial reductions in their dendritic processes and spines. Strikingly, these abnormalities became evident at a time when DNRAbs were no longer detectable in the hippocampus. These results suggest that antibody-mediated neurocognitive impairments may be highly specific, and that spatial cognition may be particularly vulnerable to DNRAb-mediated structural and functional injury to hippocampal cells that evolves after the triggering insult is no longer present.
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Key Words
- AP, alkaline phosphatase
- BBB, blood–brain barrier
- BDI, Beck depression index
- C3, C4, complements 3 and 4, respectively
- CA1 place cell
- CA1, cornus ammonis area 1 of the hippocampus
- CNS, central nervous system
- CSF, cerebrospinal fluid
- DMARD, disease-modifying drugs
- DNRAb, anti-DNA antibody reactive to the GluN2A and GluN2B subunits of the NMDAR
- DWEYS, amino acid consensus sequence (D/E, W, D/E, Y, S/G) for DNRAb binding
- FA, Freund's adjuvant
- HC, healthy control
- HEK-293T, human embryonic kidney 293 T cell
- Hippocampus
- IgG, immunoglobulin G
- LPS, lipopolysaccharide
- Lupus
- MAP, multi-antigenic polylysine backbone
- Mouse lupus model
- NMDAR, N-methyl-d-aspartate receptor
- NOR, novel object recognition
- NPSLE, neuropsychiatric lupus
- Neuropsychiatric lupus
- OPM, object place memory
- SELENA, safety of estrogens in lupus erythematosus national assessment
- SLE, systemic lupus erythematosus
- SLEDAI, systemic lupus erythematosus disease activity index
- SLICCDI, systemic lupus international collaborating clinics damage index
- dsDNA, double stranded DNA
- i.p, intraperitoneally
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Affiliation(s)
- Eric H Chang
- Laboratory of Immune & Neural Networks, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - Bruce T Volpe
- Laboratory of Functional Neuroanatomy, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA ; Department of Molecular Medicine, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY 11030, USA
| | - Meggan Mackay
- Autoimmune & Musculoskeletal Disease Center, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - Cynthia Aranow
- Autoimmune & Musculoskeletal Disease Center, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - Philip Watson
- Department of Psychology, Queens College, Flushing, NY 11367, USA
| | - Czeslawa Kowal
- Autoimmune & Musculoskeletal Disease Center, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - Justin Storbeck
- Department of Psychology, Queens College, Flushing, NY 11367, USA
| | - Paul Mattis
- Susan and Leonard Feinstein Center for Neurosciences, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - RoseAnn Berlin
- Laboratory of Functional Neuroanatomy, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - Huiyi Chen
- School of Biological Sciences, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 637551, Singapore
| | - Simone Mader
- Autoimmune & Musculoskeletal Disease Center, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - Tomás S Huerta
- Laboratory of Immune & Neural Networks, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA
| | - Patricio T Huerta
- Laboratory of Immune & Neural Networks, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA ; Autoimmune & Musculoskeletal Disease Center, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA ; Department of Molecular Medicine, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY 11030, USA
| | - Betty Diamond
- Autoimmune & Musculoskeletal Disease Center, Feinstein Institute for Medical Research, North Shore LIJ Health System, Manhasset, NY 11030, USA ; Department of Molecular Medicine, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY 11030, USA
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Sanders J, Singh A, Sterne G, Ye B, Zhou J. Learning-guided automatic three dimensional synapse quantification for drosophila neurons. BMC Bioinformatics 2015; 16:177. [PMID: 26017624 PMCID: PMC4445279 DOI: 10.1186/s12859-015-0616-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/16/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The subcellular distribution of synapses is fundamentally important for the assembly, function, and plasticity of the nervous system. Automated and effective quantification tools are a prerequisite to large-scale studies of the molecular mechanisms of subcellular synapse distribution. Common practices for synapse quantification in neuroscience labs remain largely manual or semi-manual. This is mainly due to computational challenges in automatic quantification of synapses, including large volume, high dimensions and staining artifacts. In the case of confocal imaging, optical limit and xy-z resolution disparity also require special considerations to achieve the necessary robustness. RESULTS A novel algorithm is presented in the paper for learning-guided automatic recognition and quantification of synaptic markers in 3D confocal images. The method developed a discriminative model based on 3D feature descriptors that detected the centers of synaptic markers. It made use of adaptive thresholding and multi-channel co-localization to improve the robustness. The detected markers then guided the splitting of synapse clumps, which further improved the precision and recall of the detected synapses. Algorithms were tested on lobula plate tangential cells (LPTCs) in the brain of Drosophila melanogaster, for GABAergic synaptic markers on axon terminals as well as dendrites. CONCLUSIONS The presented method was able to overcome the staining artifacts and the fuzzy boundaries of synapse clumps in 3D confocal image, and automatically quantify synaptic markers in a complex neuron such as LPTC. Comparison with some existing tools used in automatic 3D synapse quantification also proved the effectiveness of the proposed method.
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Affiliation(s)
- Jonathan Sanders
- Department of Computer Science, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Anil Singh
- Department of Computer Science, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Gabriella Sterne
- Life Sciences Institute and Department of Cell and Developmental Biology University of Michigan, Ann Arbor, MI, 48109, USA
| | - Bing Ye
- Life Sciences Institute and Department of Cell and Developmental Biology University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jie Zhou
- Department of Computer Science, Northern Illinois University, DeKalb, IL, 60115, USA.
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CREB Regulates Experience-Dependent Spine Formation and Enlargement in Mouse Barrel Cortex. Neural Plast 2015; 2015:651469. [PMID: 26075101 PMCID: PMC4436461 DOI: 10.1155/2015/651469] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 11/25/2022] Open
Abstract
Experience modifies synaptic connectivity through processes that involve dendritic spine rearrangements in neuronal circuits. Although cAMP response element binding protein (CREB) has a key function in spines changes, its role in activity-dependent rearrangements in brain regions of rodents interacting with the surrounding environment has received little attention so far.
Here we studied the effects of vibrissae trimming, a widely used model of sensory deprivation-induced cortical plasticity, on processes associated with dendritic spine rearrangements in the barrel cortex of a transgenic mouse model of CREB downregulation (mCREB mice). We found that sensory deprivation through prolonged whisker trimming leads to an increased number of thin spines in the layer V of related barrel cortex (Contra) in wild type but not mCREB mice. In the barrel field controlling spared whiskers (Ipsi), the same trimming protocol results in a CREB-dependent enlargement of dendritic spines. Last, we demonstrated that CREB regulates structural rearrangements of synapses that associate with dynamic changes of dendritic spines. Our findings suggest that CREB plays a key role in dendritic spine dynamics and synaptic circuits rearrangements that account for new brain connectivity in response to changes in the environment.
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218
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Lazcano Z, Solis O, Díaz A, Brambila E, Aguilar-Alonso P, Guevara J, Flores G. Dendritic morphology changes in neurons from the ventral hippocampus, amygdala and nucleus accumbens in rats with neonatal lesions into the prefrontal cortex. Synapse 2015; 69:314-25. [DOI: 10.1002/syn.21815] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 03/09/2015] [Accepted: 03/09/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Zayda Lazcano
- Laboratorio de Neuropsiquiatría; Instituto de Fisiología, Universidad Autónoma de Puebla; Puebla México
| | - Oscar Solis
- Laboratorio de Neuropsiquiatría; Instituto de Fisiología, Universidad Autónoma de Puebla; Puebla México
| | - Alfonso Díaz
- Facultad de Ciencias Químicas; Universidad Autónoma de Puebla; Puebla México
| | - Eduardo Brambila
- Facultad de Ciencias Químicas; Universidad Autónoma de Puebla; Puebla México
| | | | - Jorge Guevara
- Department de Bioquímica, Facultad de Medicina; Universidad Nacional Autónoma de México. D.F.; México
| | - Gonzalo Flores
- Laboratorio de Neuropsiquiatría; Instituto de Fisiología, Universidad Autónoma de Puebla; Puebla México
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George J, Soares C, Montersino A, Beique JC, Thomas GM. Palmitoylation of LIM Kinase-1 ensures spine-specific actin polymerization and morphological plasticity. eLife 2015; 4:e06327. [PMID: 25884247 PMCID: PMC4429338 DOI: 10.7554/elife.06327] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 04/16/2015] [Indexed: 12/04/2022] Open
Abstract
Precise regulation of the dendritic spine actin cytoskeleton is critical for neurodevelopment and neuronal plasticity, but how neurons spatially control actin dynamics is not well defined. Here, we identify direct palmitoylation of the actin regulator LIM kinase-1 (LIMK1) as a novel mechanism to control spine-specific actin dynamics. A conserved palmitoyl-motif is necessary and sufficient to target LIMK1 to spines and to anchor LIMK1 in spines. ShRNA knockdown/rescue experiments reveal that LIMK1 palmitoylation is essential for normal spine actin polymerization, for spine-specific structural plasticity and for long-term spine stability. Palmitoylation is critical for LIMK1 function because this modification not only controls LIMK1 targeting, but is also essential for LIMK1 activation by its membrane-localized upstream activator PAK. These novel roles for palmitoylation in the spatial control of actin dynamics and kinase signaling provide new insights into structural plasticity mechanisms and strengthen links between dendritic spine impairments and neuropathological conditions. DOI:http://dx.doi.org/10.7554/eLife.06327.001 Neurons transmit information from one cell to the next by passing signals across junctions called synapses. For the neurons that receive these signals, these junctions are found on fine branch-like structures called dendrites that stick out of the cell. Dendrites themselves are decorated with smaller structures called dendritic spines, which typically receive information from one other neuron via a single synapse. Dendritic spines form in response to the signaling activity of the neuron, and problems with forming these spines have been linked to conditions such as autism and schizophrenia. Dendritic spines are created by the cell's cytoskeleton—a network of proteins that creates a constantly changing internal scaffold that shapes cells. One cytoskeleton protein called actin exists as thin filaments that can be extended or broken up by other proteins. It is not fully understood how actin is regulated in the dendritic spines. However, some researchers thought that the proteins that control the formation of the actin filaments would need to be localized to the dendritic spines to ensure that the spines form correctly. Some proteins can be made to localize to cell membranes by attaching a molecule called palmitic acid to them. Previous research has suggested that this ‘palmitoylation’ process is particularly important in neurons. Through a combination of experimental techniques, George et al. now show that palmitoylation is required to localize a protein called LIMK1, which regulates the construction of actin filaments, to the tips of dendritic spines. Further experiments showed that blocking the palmitoylation of LIMK1 alters how actin filaments form, makes spines unstable and causes synapses to be lost. George et al. also discovered that palmitoylation is necessary for LIMK1 to be activated by another protein that is found at dendritic spine membranes. This ‘dual-control’ mechanism makes it possible to precisely control where actin filaments form within dendritic spines. In addition to LIMK1, several other enzymes are also modified by palmitoylation. It will therefore be interesting to determine whether this dual control mechanism is broadly used by neurons to precisely regulate the structure and function of individual spines and synapses. DOI:http://dx.doi.org/10.7554/eLife.06327.002
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Affiliation(s)
- Joju George
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, United States
| | - Cary Soares
- Heart and Stroke Partnership for Stroke Recovery, University of Ottawa, Ottawa, Canada
| | - Audrey Montersino
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, United States
| | - Jean-Claude Beique
- Heart and Stroke Partnership for Stroke Recovery, University of Ottawa, Ottawa, Canada
| | - Gareth M Thomas
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, United States
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Rheb activation disrupts spine synapse formation through accumulation of syntenin in tuberous sclerosis complex. Nat Commun 2015; 6:6842. [PMID: 25880340 DOI: 10.1038/ncomms7842] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 03/03/2015] [Indexed: 01/14/2023] Open
Abstract
Rheb is a small GTP-binding protein and its GTPase activity is activated by the complex of Tsc1 and Tsc2 whose mutations cause tuberous sclerosis complex (TSC). We previously reported that cultured TSC neurons showed impaired spine synapse morphogenesis in an mTORC1-independent manner. Here we show that the PDZ protein syntenin preferentially binds to the GDP-bound form of Rheb. The levels of syntenin are significantly higher in TSC neurons than in wild-type neurons because the Rheb-GDP-syntenin complex is prone to proteasomal degradation. Accumulated syntenin in TSC neurons disrupts spine synapse formation through inhibition of the association between syndecan-2 and calcium/calmodulin-dependent serine protein kinase. Instead, syntenin enhances excitatory shaft synapse formation on dendrites by interacting with ephrinB3. Downregulation of syntenin in TSC neurons restores both spine and shaft synapse densities. These findings suggest that Rheb-syntenin signalling may be a novel therapeutic target for abnormalities in spine and shaft synapses in TSC neurons.
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221
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Flupirtine attenuates chronic restraint stress-induced cognitive deficits and hippocampal apoptosis in male mice. Behav Brain Res 2015; 288:1-10. [PMID: 25869780 DOI: 10.1016/j.bbr.2015.04.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 04/01/2015] [Accepted: 04/04/2015] [Indexed: 02/07/2023]
Abstract
Chronic restraint stress (CRS) causes hippocampal neurodegeneration and hippocampus-dependent cognitive deficits. Flupirtine represents neuroprotective effects and we have previously shown that flupirtine can protect against memory impairment induced by acute stress. The present study aimed to investigate whether flupirtine could alleviate spatial learning and memory impairment and hippocampal apoptosis induced by CRS. CRS mice were restrained in well-ventilated Plexiglass tubes for 6h daily beginning from 10:00 to 16:00 for 21 consecutive days. Mice were injected with flupirtine (10mg/kg and 25mg/kg) or vehicle (10% DMSO) 30min before restraint stress for 21 days. After stressor cessation, the spatial learning and memory, dendritic spine density, injured neurons and the levels of Bcl-2, Bax, p-Akt, p-GSK-3β, p-Erk1/2 and synaptophysin of hippocampal tissues were examined. Our results showed that flupirtine significantly prevented spatial learning and memory impairment induced by CRS in the Morris water maze. In addition, flupirtine (10mg/kg and 25mg/kg) treatment alleviated neuronal apoptosis and the reduction of dendritic spine density and synaptophysin expression in the hippocampal CA1 region of CRS mice. Furthermore, flupirtine (10mg/kg and 25mg/kg) treatment significantly decreased the expression of Bax and increased the p-Akt and p-GSK-3β, and flupirtine (25mg/kg) treatment up-regulated the p-Erk1/2 in the hippocampus of CRS mice. These results suggested that flupirtine exerted protective effects on the CRS-induced cognitive impairment and hippocampal neuronal apoptosis, which is possibly associated with the activation of Akt/GSK-3β and Erk1/2 signaling pathways.
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Zhvania MG, Ksovreli M, Japaridze NJ, Lordkipanidze TG. Ultrastructural changes to rat hippocampus in pentylenetetrazol- and kainic acid-induced status epilepticus: A study using electron microscopy. Micron 2015; 74:22-9. [PMID: 25978010 DOI: 10.1016/j.micron.2015.03.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 02/06/2023]
Abstract
A pentylenetetrazol (PTZ)-induced status epilepticus model in rats was used in the study. The brains were studied one month after treatment. Ultrastructural observations using electron microscopy performed on the neurons, glial cells, and synapses, in the hippocampal CA1 region of epileptic brains, demonstrated the following major changes over normal control brain tissue. (i) There is ultrastructural alterations in some neurons, glial cells and synapses in the hippocampal CA1 region. (ii) The destruction of cellular organelles and peripheral, partial or even total chromatolysis in some pyramidal cells and in interneurons are observed. Several astrocytes are proliferated or activated. Presynaptic terminals with granular vesicles and degenerated presynaptic profiles are rarely observed. (iii) The alterations observed are found to be dependent on the frequency of seizure activities following the PTZ treatment. It was observed that if seizure episodes are frequent and severe, the ultrastructure of hippocampal area is significantly changed. Interestingly, the ultrastructure of CA1 area is found to be only moderately altered if seizure episodes following the status epilepticus are rare and more superficial; (iv) alterations in mitochondria and dendrites are among the most common ultrastructural changes seen, suggesting cell stress and changes to cellular metabolism. These morphological changes, observed in brain neurons in status epilepticus, are a reflection of epileptic pathophysiology. Further studies at the chemical and molecular level of neurotransmitter release, such as at the level of porosomes (secretory portals) at the presynaptic membrane, will further reveal molecular details of these changes.
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Affiliation(s)
- Mzia G Zhvania
- Institute of Chemical Biology, Ilia State University, 3/5 K. Cholokhashvili Avenue, 0162 Tbilisi, Georgia; Department of Brain Ultrastructure and Nanoarchitecture, I. Beriitashvili Center of Experimental BioMedicine, 14, Gotua Street, 0160 Tbilisi, Georgia.
| | - Mariam Ksovreli
- Institute of Chemical Biology, Ilia State University, 3/5 K. Cholokhashvili Avenue, 0162 Tbilisi, Georgia.
| | - Nadezhda J Japaridze
- Department of Brain Ultrastructure and Nanoarchitecture, I. Beriitashvili Center of Experimental BioMedicine, 14, Gotua Street, 0160 Tbilisi, Georgia; New Vision University, 1A Evgeni Mikeladze Street, 0158 Tbilisi, Georgia.
| | - Tamar G Lordkipanidze
- Institute of Chemical Biology, Ilia State University, 3/5 K. Cholokhashvili Avenue, 0162 Tbilisi, Georgia; Department of Brain Ultrastructure and Nanoarchitecture, I. Beriitashvili Center of Experimental BioMedicine, 14, Gotua Street, 0160 Tbilisi, Georgia.
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Ochs SM, Dorostkar MM, Aramuni G, Schön C, Filser S, Pöschl J, Kremer A, Van Leuven F, Ovsepian SV, Herms J. Loss of neuronal GSK3β reduces dendritic spine stability and attenuates excitatory synaptic transmission via β-catenin. Mol Psychiatry 2015; 20:482-9. [PMID: 24912492 PMCID: PMC4378257 DOI: 10.1038/mp.2014.55] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 04/14/2014] [Accepted: 04/17/2014] [Indexed: 02/06/2023]
Abstract
Central nervous glycogen synthase kinase 3β (GSK3β) is implicated in a number of neuropsychiatric diseases, such as bipolar disorder, depression, schizophrenia, fragile X syndrome or anxiety disorder. Many drugs employed to treat these conditions inhibit GSK3β either directly or indirectly. We studied how conditional knockout of GSK3β affected structural synaptic plasticity. Deletion of the GSK3β gene in a subset of cortical and hippocampal neurons in adult mice led to reduced spine density. In vivo imaging revealed that this was caused by a loss of persistent spines, whereas stabilization of newly formed spines was reduced. In electrophysiological recordings, these structural alterations correlated with a considerable drop in the frequency and amplitude of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-dependent miniature excitatory postsynaptic currents. Expression of constitutively active β-catenin caused reduction in spine density and electrophysiological alterations similar to GSK3β knockout, suggesting that the effects of GSK3β knockout were mediated by the accumulation of β-catenin. In summary, changes of dendritic spines, both in quantity and in morphology, are correlates of experience-dependent synaptic plasticity; thus, these results may help explain the mechanism of action of psychotropic drugs inhibiting GSK3β.
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Affiliation(s)
- S M Ochs
- German Center for Neurodegenerative Diseases (DZNE), Ludwig Maximilian University Munich, Munich, Germany
| | - M M Dorostkar
- Center for Neuropathology and Prion Research, Ludwig Maximilian University, Munich, Germany
| | - G Aramuni
- German Center for Neurodegenerative Diseases (DZNE), Ludwig Maximilian University Munich, Munich, Germany
| | - C Schön
- Center for Neuropathology and Prion Research, Ludwig Maximilian University, Munich, Germany
| | - S Filser
- German Center for Neurodegenerative Diseases (DZNE), Ludwig Maximilian University Munich, Munich, Germany
| | - J Pöschl
- Center for Neuropathology and Prion Research, Ludwig Maximilian University, Munich, Germany
| | - A Kremer
- Experimental Genetics Group-LEGTEGG, Department of Human Genetics KU Leuven, Leuven, Belgium
| | - F Van Leuven
- Experimental Genetics Group-LEGTEGG, Department of Human Genetics KU Leuven, Leuven, Belgium
| | - S V Ovsepian
- German Center for Neurodegenerative Diseases (DZNE), Ludwig Maximilian University Munich, Munich, Germany
| | - J Herms
- German Center for Neurodegenerative Diseases (DZNE), Ludwig Maximilian University Munich, Munich, Germany,Center for Neuropathology and Prion Research, Ludwig Maximilian University, Munich, Germany,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany,German Center for Neurodegenerative Diseases (DZNE), Ludwig Maximilian University Munich, Feodor-Lynen-Strasse 23, Munich 81377, Germany. E-mail:
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Jiang X, Chai GS, Wang ZH, Hu Y, Li XG, Ma ZW, Wang Q, Wang JZ, Liu GP. Spatial training preserves associative memory capacity with augmentation of dendrite ramification and spine generation in Tg2576 mice. Sci Rep 2015; 5:9488. [PMID: 25820815 PMCID: PMC4377552 DOI: 10.1038/srep09488] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 03/09/2015] [Indexed: 01/12/2023] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder and there is currently no efficient cure for this devastating disease. Cognitive stimulation can delay memory loss during aging and in patients with mild cognitive impairment. In 3 × Tg-AD mice, training decreased the neuropathologies with transient amelioration of memory decline. However, the neurobiological mechanisms underlying the learning-improved memory capacity are poorly understood. Here, we found in Tg2576 mice spatial training in Morris water maze (MWM) remarkably improved the subsequent associative memory acquisition detected by contextual fear conditioning. We also found that spatial training enhanced long term potentiation, dendrite ramification and spine generation in hippocampal dentate gyrus (DG) and CA1 neurons at 24 h after the training. In the molecular level, the MWM training remarkably activated calcium/calmodulin-dependent protein kinase II (CaMKII) with elevation of glutamate AMPA receptor GluA1 subunit (GluA1), postsynaptic density protein 93 (PSD93) and postsynaptic density protein 95 (PSD95) in the hippocampus. Finally, the training also significantly ameliorated AD-like tau and amyloid pathologies. We conclude that spatial training in MWM preserves associative memory capacity in Tg2576 mice, and the mechanisms involve augmentation of dendrite ramification and spine generation in hippocampus.
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Affiliation(s)
- Xia Jiang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
- Department of Pathology, Hubei University of Chinese Medicine, Wuhan, 430065. P. R. China
| | - Gao-Shang Chai
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
- Department of Basic Medicine, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu Province, 214122, P. R. China
| | - Zhi-Hao Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
| | - Yu Hu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
| | - Xiao-Guang Li
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
| | - Zhi-Wei Ma
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
| | - Qun Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, JS 226001, China
| | - Gong-Ping Liu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, the School of Basal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. P. R. China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, JS 226001, China
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225
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Evans JC, Robinson CM, Shi M, Webb DJ. The guanine nucleotide exchange factor (GEF) Asef2 promotes dendritic spine formation via Rac activation and spinophilin-dependent targeting. J Biol Chem 2015; 290:10295-308. [PMID: 25750125 DOI: 10.1074/jbc.m114.605543] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Indexed: 11/06/2022] Open
Abstract
Dendritic spines are actin-rich protrusions that establish excitatory synaptic contacts with surrounding neurons. Reorganization of the actin cytoskeleton is critical for the development and plasticity of dendritic spines, which is the basis for learning and memory. Rho family GTPases are emerging as important modulators of spines and synapses, predominantly through their ability to regulate actin dynamics. Much less is known, however, about the function of guanine nucleotide exchange factors (GEFs), which activate these GTPases, in spine and synapse development. In this study we show that the Rho family GEF Asef2 is found at synaptic sites, where it promotes dendritic spine and synapse formation. Knockdown of endogenous Asef2 with shRNAs impairs spine and synapse formation, whereas exogenous expression of Asef2 causes an increase in spine and synapse density. This effect of Asef2 on spines and synapses is abrogated by expression of GEF activity-deficient Asef2 mutants or by knockdown of Rac, suggesting that Asef2-Rac signaling mediates spine development. Because Asef2 interacts with the F-actin-binding protein spinophilin, which localizes to spines, we investigated the role of spinophilin in Asef2-promoted spine formation. Spinophilin recruits Asef2 to spines, and knockdown of spinophilin hinders spine and synapse formation in Asef2-expressing neurons. Furthermore, inhibition of N-methyl-d-aspartate receptor (NMDA) activity blocks spinophilin-mediated localization of Asef2 to spines. These results collectively point to spinophilin-Asef2-Rac signaling as a novel mechanism for the development of dendritic spines and synapses.
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Affiliation(s)
- J Corey Evans
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and
| | - Cristina M Robinson
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and
| | - Mingjian Shi
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and
| | - Donna J Webb
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and the Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee 37235
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226
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Brečević L, Rinčić M, Krsnik Ž, Sedmak G, Hamid AB, Kosyakova N, Galić I, Liehr T, Borovečki F. Association of new deletion/duplication region at chromosome 1p21 with intellectual disability, severe speech deficit and autism spectrum disorder-like behavior: an all-in approach to solving the DPYD enigma. Transl Neurosci 2015; 6:59-86. [PMID: 28123791 PMCID: PMC4936614 DOI: 10.1515/tnsci-2015-0007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/29/2014] [Indexed: 12/14/2022] Open
Abstract
We describe an as yet unreported neocentric small supernumerary marker chromosome (sSMC) derived from chromosome 1p21.3p21.2. It was present in 80% of the lymphocytes in a male patient with intellectual disability, severe speech deficit, mild dysmorphic features, and hyperactivity with elements of autism spectrum disorder (ASD). Several important neurodevelopmental genes are affected by the 3.56 Mb copy number gain of 1p21.3p21.2, which may be considered reciprocal in gene content to the recently recognized 1p21.3 microdeletion syndrome. Both 1p21.3 deletions and the presented duplication display overlapping symptoms, fitting the same disorder category. Contribution of coding and non-coding genes to the phenotype is discussed in the light of cellular and intercellular homeostasis disequilibrium. In line with this the presented 1p21.3p21.2 copy number gain correlated to 1p21.3 microdeletion syndrome verifies the hypothesis of a cumulative effect of the number of deregulated genes - homeostasis disequilibrium leading to overlapping phenotypes between microdeletion and microduplication syndromes. Although miR-137 appears to be the major player in the 1p21.3p21.2 region, deregulation of the DPYD (dihydropyrimidine dehydrogenase) gene may potentially affect neighboring genes underlying the overlapping symptoms present in both the copy number loss and copy number gain of 1p21. Namely, the all-in approach revealed that DPYD is a complex gene whose expression is epigenetically regulated by long non-coding RNAs (lncRNAs) within the locus. Furthermore, the long interspersed nuclear element-1 (LINE-1) L1MC1 transposon inserted in DPYD intronic transcript 1 (DPYD-IT1) lncRNA with its parasites, TcMAR-Tigger5b and pair of Alu repeats appears to be the “weakest link” within the DPYD gene liable to break. Identification of the precise mechanism through which DPYD is epigenetically regulated, and underlying reasons why exactly the break (FRA1E) happens, will consequently pave the way toward preventing severe toxicity to the antineoplastic drug 5-fluorouracil (5-FU) and development of the causative therapy for the dihydropyrimidine dehydrogenase deficiency.
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Affiliation(s)
- Lukrecija Brečević
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
- Department for Functional Genomics, Center for Translational and Clinical Research, University of Zagreb Medical School, University Hospital Center Zagreb, Šalata 2, 10000 Zagreb, Croatia
- E-mail: ;
| | - Martina Rinčić
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
- Department for Functional Genomics, Center for Translational and Clinical Research, University of Zagreb Medical School, University Hospital Center Zagreb, Šalata 2, 10000 Zagreb, Croatia
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Željka Krsnik
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
| | - Goran Sedmak
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
| | - Ahmed B. Hamid
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Nadezda Kosyakova
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Ivan Galić
- Center for Rehabilitation Stančić, Stančić bb, 10370 Stančić, Croatia
| | - Thomas Liehr
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Fran Borovečki
- Department for Functional Genomics, Center for Translational and Clinical Research, University of Zagreb Medical School, University Hospital Center Zagreb, Šalata 2, 10000 Zagreb, Croatia
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227
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Abstract
Golgi silver impregnation techniques remain ideal methods for the visualization of the neurons as a whole in formalin fixed brains and paraffin sections, enabling to obtain insight into the morphological and morphometric characters of the dendritic arbor, and the estimation of the morphology of the spines and the spinal density, since they delineate the profile of nerve cells with unique clarity and precision. In addition, the Golgi technique enables the study of the topographic relationships between neurons and neuronal circuits in normal conditions, and the following of the spatiotemporal morphological alterations occurring during degenerative processes. The Golgi technique has undergone many modifications in order to be enhanced and to obtain the optimal and maximal visualization of neurons and neuronal processes, the minimal precipitations, the abbreviation of the time required for the procedure, enabling the accurate study and description of specific structures of the brain. In the visualization of the sequential stages of the neuronal degeneration and death, the Golgi method plays a prominent role in the visualization of degenerating axons and dendrites, synaptic “boutons,” and axonal terminals and organelles of the cell body. In addition, new versions of the techniques increases the capacity of precise observation of the neurofibrillary degeneration, the proliferation of astrocytes, the activation of the microglia, and the morphology of capillaries in autopsy material of debilitating diseases of the central nervous system.
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228
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Risher WC, Patel S, Kim IH, Uezu A, Bhagat S, Wilton DK, Pilaz LJ, Singh Alvarado J, Calhan OY, Silver DL, Stevens B, Calakos N, Soderling SH, Eroglu C. Astrocytes refine cortical connectivity at dendritic spines. eLife 2014; 3. [PMID: 25517933 PMCID: PMC4286724 DOI: 10.7554/elife.04047] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 12/16/2014] [Indexed: 11/13/2022] Open
Abstract
During cortical synaptic development, thalamic axons must establish synaptic connections despite the presence of the more abundant intracortical projections. How thalamocortical synapses are formed and maintained in this competitive environment is unknown. Here, we show that astrocyte-secreted protein hevin is required for normal thalamocortical synaptic connectivity in the mouse cortex. Absence of hevin results in a profound, long-lasting reduction in thalamocortical synapses accompanied by a transient increase in intracortical excitatory connections. Three-dimensional reconstructions of cortical neurons from serial section electron microscopy (ssEM) revealed that, during early postnatal development, dendritic spines often receive multiple excitatory inputs. Immuno-EM and confocal analyses revealed that majority of the spines with multiple excitatory contacts (SMECs) receive simultaneous thalamic and cortical inputs. Proportion of SMECs diminishes as the brain develops, but SMECs remain abundant in Hevin-null mice. These findings reveal that, through secretion of hevin, astrocytes control an important developmental synaptic refinement process at dendritic spines.
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Affiliation(s)
- W Christopher Risher
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Sagar Patel
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Il Hwan Kim
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Akiyoshi Uezu
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Srishti Bhagat
- Department of Neurobiology, Duke University Medical Center, Durham, United States
| | - Daniel K Wilton
- Department of Neurology, FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States
| | - Louis-Jan Pilaz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
| | | | - Osman Y Calhan
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Debra L Silver
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Beth Stevens
- Department of Neurology, FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, United States
| | - Nicole Calakos
- Department of Neurobiology, Duke University Medical Center, Durham, United States
| | - Scott H Soderling
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, United States
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229
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Colín-Barenque L, Pedraza-Chaverri J, Medina-Campos O, Jimenez-Martínez R, Bizarro-Nevares P, González-Villalva A, Rojas-Lemus M, Fortoul TI. Functional and morphological olfactory bulb modifications in mice after vanadium inhalation. Toxicol Pathol 2014; 43:282-91. [PMID: 25492423 DOI: 10.1177/0192623314548668] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neurodegenerative disorders, such as Parkinson's and Alzheimer's diseases, have olfaction impairment. These pathologies have also been linked to environmental pollutants. Vanadium is a pollutant, and its toxic mechanisms are related to the production of oxidative stress. In this study, we evaluated the effects of inhaled vanadium on olfaction, the olfactory bulb antioxidant, through histological and ultrastructural changes in granule cells. Mice in control group were made to inhale saline; the experimental group inhaled 0.02-M vanadium pentoxide (V2O5) for 1 hr twice a week for 4 weeks. Animals were sacrificed at 1, 2, 3, and 4 weeks after inhalation. Olfactory function was evaluated by the odorant test. The activity of glutathione peroxidase (GPx) and glutathione reductase (GR) was assayed in olfactory bulbs and processed for rapid Golgi method and ultrastructural analysis. Results show that olfactory function decreased at 4-week vanadium exposure; granule cells showed a decrease in dendritic spine density and increased lipofuscin, Golgi apparatus vacuolation, apoptosis, and necrosis. The activity of GPx and GR in the olfactory bulb was increased compared to that of the controls. Our results demonstrate that vanadium inhalation disturbs olfaction, histology, and the ultrastructure of the granule cells that might be associated with oxidative stress, a risk factor in neurodegenerative diseases.
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Affiliation(s)
| | - Jose Pedraza-Chaverri
- Department of Biology, Facultad de Química, Ciudad Universitaria México, D.F., Mexico. UNAM
| | - Omar Medina-Campos
- Department of Biology, Facultad de Química, Ciudad Universitaria México, D.F., Mexico. UNAM
| | - Ruben Jimenez-Martínez
- Departament of Cellular and Tissular Biology, School of Medicine, México D.F., Mexico. UNAM
| | | | | | - Marcela Rojas-Lemus
- Departament of Cellular and Tissular Biology, School of Medicine, México D.F., Mexico. UNAM
| | - Teresa I Fortoul
- Departament of Cellular and Tissular Biology, School of Medicine, México D.F., Mexico. UNAM
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230
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Edwards J, Daniel E, Kinney J, Bartol T, Sejnowski T, Johnston D, Harris K, Bajaj C. VolRoverN: enhancing surface and volumetric reconstruction for realistic dynamical simulation of cellular and subcellular function. Neuroinformatics 2014; 12:277-89. [PMID: 24100964 DOI: 10.1007/s12021-013-9205-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Establishing meaningful relationships between cellular structure and function requires accurate morphological reconstructions. In particular, there is an unmet need for high quality surface reconstructions to model subcellular and synaptic interactions among neurons and glia at nanometer resolution. We address this need with VolRoverN, a software package that produces accurate, efficient, and automated 3D surface reconstructions from stacked 2D contour tracings. While many techniques and tools have been developed in the past for 3D visualization of cellular structure, the reconstructions from VolRoverN meet specific quality criteria that are important for dynamical simulations. These criteria include manifoldness, water-tightness, lack of self- and object-object-intersections, and geometric accuracy. These enhanced surface reconstructions are readily extensible to any cell type and are used here on spiny dendrites with complex morphology and axons from mature rat hippocampal area CA1. Both spatially realistic surface reconstructions and reduced skeletonizations are produced and formatted by VolRoverN for easy input into analysis software packages for neurophysiological simulations at multiple spatial and temporal scales ranging from ion electro-diffusion to electrical cable models.
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Affiliation(s)
- John Edwards
- Department of Computer Science, ICES, The University of Texas, Austin, TX, USA
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231
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Araya R. Input transformation by dendritic spines of pyramidal neurons. Front Neuroanat 2014; 8:141. [PMID: 25520626 PMCID: PMC4251451 DOI: 10.3389/fnana.2014.00141] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 11/11/2014] [Indexed: 11/13/2022] Open
Abstract
In the mammalian brain, most inputs received by a neuron are formed on the dendritic tree. In the neocortex, the dendrites of pyramidal neurons are covered by thousands of tiny protrusions known as dendritic spines, which are the major recipient sites for excitatory synaptic information in the brain. Their peculiar morphology, with a small head connected to the dendritic shaft by a slender neck, has inspired decades of theoretical and more recently experimental work in an attempt to understand how excitatory synaptic inputs are processed, stored and integrated in pyramidal neurons. Advances in electrophysiological, optical and genetic tools are now enabling us to unravel the biophysical and molecular mechanisms controlling spine function in health and disease. Here I highlight relevant findings, challenges and hypotheses on spine function, with an emphasis on the electrical properties of spines and on how these affect the storage and integration of excitatory synaptic inputs in pyramidal neurons. In an attempt to make sense of the published data, I propose that the raison d'etre for dendritic spines lies in their ability to undergo activity-dependent structural and molecular changes that can modify synaptic strength, and hence alter the gain of the linearly integrated sub-threshold depolarizations in pyramidal neuron dendrites before the generation of a dendritic spike.
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Affiliation(s)
- Roberto Araya
- Department of Neurosciences, Faculty of Medicine, University of Montreal Montreal, QC, Canada
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232
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Anaya-Martínez V, Gutierrez-Valdez AL, Ordoñez-Librado JL, Montiel-Flores E, Sánchez-Betancourt J, Sánchez Vázquez del Mercado C, Reynoso-Erazo L, Tron-Alvarez R, Avila-Costa MR. The presence of perforated synapses in the striatum after dopamine depletion, is this a sign of maladaptive brain plasticity? Microscopy (Oxf) 2014; 63:427-35. [PMID: 25246608 DOI: 10.1093/jmicro/dfu032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Synaptic plasticity is the process by which long-lasting changes take place at synaptic connections. The phenomenon itself is complex and can involve many levels of organization. Some authors separate forms into adaptations that have positive or negative consequences for the individual. It has been hypothesized that an increase in the number of synapses may represent a structural basis for the enduring expression of synaptic plasticity during some events that involve memory and learning; also, it has been suggested that perforated synapses increase in number after some diseases and experimental situations. The aim of this study was to analyze whether dopamine depletion induces changes in the synaptology of the corpus striatum of rats after the unilateral injection of 6-OHDA. The findings suggest that after the lesion, both contralateral and ipsilateral striata exhibit an increased length of the synaptic ending in ipsilateral (since third day) and contralateral striatum (since Day 20), loss of axospinous synapses in ipsilateral striatum and a significant increment in the number of perforated synapses, suggesting brain plasticity that might be deleterious for the spines, because this type of synaptic contacts are presumably excitatory, and in the absence of the modulatory effects of dopamine, the neuron could die through excitotoxic mechanisms. Thus, we can conclude that the presence of perforated synapses after striatal dopamine depletion might be a form of maladaptive synaptic plasticity.
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Affiliation(s)
- Verónica Anaya-Martínez
- Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - Ana Luisa Gutierrez-Valdez
- Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - Jose Luis Ordoñez-Librado
- Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - Enrique Montiel-Flores
- Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - Javier Sánchez-Betancourt
- Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - César Sánchez Vázquez del Mercado
- Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - Leonardo Reynoso-Erazo
- Health Education Project, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - Rocío Tron-Alvarez
- Health Education Project, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
| | - Maria Rosa Avila-Costa
- Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico
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233
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Abstract
We present a technique for mapping dispersion anisotropy of neurites in the human brain in vivo. Neurites are the structural substrate of the brain that support its function. Measures of their morphology from histology provide the gold standard for diagnosing various brain disorders. Some of these measures, e.g. neurite density and orientation dispersion, can now be mapped in vivo using diffusion MRI, enabling their use in clinical applications. However, in vivo methods for estimating more sophisticated measures, such as dispersion anisotropy, have yet to be demonstrated. Dispersion anisotropy allows more refined characterisation of the complex neurite configurations such as fanning or bending axons; its quantification in vivo can offer new imaging markers. The aim of this work is to develop a method to estimate dispersion anisotropy in vivo. Our approach builds on the Neurite Orientation Dispersion and Density Imaging (NODDI), an existing clinically feasible diffusion MRI technique. The estimation of dispersion anisotropy is achieved by incorporating Bingham distribution as the neurite orientation distribution function, with no additional acquisition requirements. We show the first in vivo maps of dispersion anisotropy and demonstrate that it can be estimated accurately with a clinically feasible protocol. We additionally show that the original NODDI is robust to the effects of dispersion anisotropy, when the the new parameter is not of interest.
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234
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Szczesna K, de la Caridad O, Petazzi P, Soler M, Roa L, Saez MA, Fourcade S, Pujol A, Artuch-Iriberri R, Molero-Luis M, Vidal A, Huertas D, Esteller M. Improvement of the Rett syndrome phenotype in a MeCP2 mouse model upon treatment with levodopa and a dopa-decarboxylase inhibitor. Neuropsychopharmacology 2014; 39:2846-56. [PMID: 24917201 PMCID: PMC4200495 DOI: 10.1038/npp.2014.136] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/28/2014] [Accepted: 06/02/2014] [Indexed: 12/12/2022]
Abstract
Rett Syndrome is a neurodevelopmental autism spectrum disorder caused by mutations in the gene coding for methyl CpG-binding protein (MeCP2). The disease is characterized by abnormal motor, respiratory, cognitive impairment, and autistic-like behaviors. No effective treatment of the disorder is available. Mecp2 knockout mice have a range of physiological and neurological abnormalities that resemble the human syndrome and can be used as a model to interrogate new therapies. Herein, we show that the combined administration of Levodopa and a Dopa-decarboxylase inhibitor in RTT mouse models is well tolerated, diminishes RTT-associated symptoms, and increases life span. The amelioration of RTT symptomatology is particularly significant in those features controlled by the dopaminergic pathway in the nigrostratium, such as mobility, tremor, and breathing. Most important, the improvement of the RTT phenotype upon use of the combined treatment is reflected at the cellular level by the development of neuronal dendritic growth. However, much work is required to extend the duration of the benefit of the described preclinical treatment.
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Affiliation(s)
- Karolina Szczesna
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Olga de la Caridad
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Paolo Petazzi
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Marta Soler
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Laura Roa
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Mauricio A Saez
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Stéphane Fourcade
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Institute of Neuropathology, University of Barcelona, Barcelona, Spain,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Institute of Neuropathology, University of Barcelona, Barcelona, Spain,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain,Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Rafael Artuch-Iriberri
- Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain,Neurometabolic Unit, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Marta Molero-Luis
- Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain,Neurometabolic Unit, Hospital Sant Joan de Déu, Barcelona, Spain
| | - August Vidal
- Department of Pathology, Bellvitge University Hospital, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Dori Huertas
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 3rd Floor, Hospital Duran i Reynals, Avenue Gran Via 199-203, L'Hospitalet, Barcelona 08908, Catalonia, Spain, Tel: +34 932607253, Fax: +34 932607140, E-mail: or
| | - Manel Esteller
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain,Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain,Department of Physiological Sciences II, School of Medicine, University of Barcelona, Barcelona, Spain,Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 3rd Floor, Hospital Duran i Reynals, Avenue Gran Via 199-203, L'Hospitalet, Barcelona 08908, Catalonia, Spain, Tel: +34 932607253, Fax: +34 932607140, E-mail: or
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235
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Haim A, Sherer M, Leuner B. Gestational stress induces persistent depressive-like behavior and structural modifications within the postpartum nucleus accumbens. Eur J Neurosci 2014; 40:3766-73. [PMID: 25359225 DOI: 10.1111/ejn.12752] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 09/10/2014] [Accepted: 09/11/2014] [Indexed: 12/22/2022]
Abstract
Postpartum depression (PPD) is a common complication following childbirth experienced by one in every five new mothers. Pregnancy stress enhances vulnerability to PPD and has also been shown to increase depressive-like behavior in postpartum rats. Thus, gestational stress may be an important translational risk factor that can be used to investigate the neurobiological mechanisms underlying PPD. Here we examined the effects of gestational stress on depressive-like behavior during the early/mid and late postpartum periods and evaluated whether this was accompanied by altered structural plasticity in the nucleus accumbens (NAc), a brain region that has been linked to PPD. We show that early/mid (postpartum day 8) postpartum female rats exhibited more depressive-like behavior in the forced swim test as compared with late postpartum females (postpartum day 22). However, 2 weeks of restraint stress during pregnancy increased depressive-like behavior regardless of postpartum timepoint. In addition, dendritic length, branching and spine density on medium spiny neurons in the NAc shell were diminished in postpartum rats that experienced gestational stress although stress-induced reductions in spine density were evident only in early/mid postpartum females. In the NAc core, structural plasticity was not affected by gestational stress but late postpartum females exhibited lower spine density and reduced dendritic length. Overall, these data not only demonstrate structural changes in the NAc across the postpartum period, they also show that postpartum depressive-like behavior following exposure to gestational stress is associated with compromised structural plasticity in the NAc and thus may provide insight into the neural changes that could contribute to PPD.
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Affiliation(s)
- Achikam Haim
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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236
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Ma QL, Yang F, Frautschy SA, Cole GM. PAK in Alzheimer disease, Huntington disease and X-linked mental retardation. CELLULAR LOGISTICS 2014; 2:117-125. [PMID: 23162743 PMCID: PMC3490962 DOI: 10.4161/cl.21602] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Developmental cognitive deficits including X-linked mental retardation (XLMR) can be caused by mutations in P21-activated kinase 3 (PAK3) that disrupt actin dynamics in dendritic spines. Neurodegenerative diseases such as Alzheimer disease (AD), where both PAK1 and PAK3 are dysregulated, may share final common pathways with XLMR. Independent of familial mutation, cognitive deficits emerging with aging, notably AD, begin after decades of normal function. This prolonged prodromal period involves the buildup of amyloid-β (Aβ) extracellular plaques and intraneuronal neurofibrillary tangles (NFT). Subsequently region dependent deficits in synapses, dendritic spines and cognition coincide with dysregulation in PAK1 and PAK. Specifically proximal to decline, cytoplasmic levels of actin-regulating Rho GTPase and PAK1 kinase are decreased in moderate to severe AD, while aberrant activation and translocation of PAK1 appears around the onset of cognitive deficits. Downstream to PAK1, LIM kinase inactivates cofilin, contributing to cofilin pathology, while the activation of Rho-dependent kinase ROCK increases Aβ production. Aβ activation of fyn disrupts neuronal PAK1 and ROCK-mediated signaling, resulting in synaptic deficits. Reductions in PAK1 by the anti-amyloid compound curcumin suppress synaptotoxicity. Similarly other neurological disorders, including Huntington disease (HD) show dysregulation of PAKs. PAK1 modulates mutant huntingtin toxicity by enhancing huntingtin aggregation, and inhibition of PAK activity protects HD as well as fragile X syndrome (FXS) symptoms. Since PAK plays critical roles in learning and memory and is disrupted in many cognitive disorders, targeting PAK signaling in AD, HD and XLMR may be a novel common therapeutic target for AD, HD and XLMR.
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Affiliation(s)
- Qiu-Lan Ma
- Department of Neurology; University of California Los Angeles; Los Angeles, CA USA ; Geriatric Research and Clinical Center; Greater Los Angeles Veterans Affairs Healthcare System; West Los Angeles Medical Center; Los Angeles, CA USA
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237
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Choi YS, Eom SY, Park H, Ali SF, Lantz-McPeak SM, Kleinman MT, Kim YD, Kim H. Toxicity of low doses of ultrafine diesel exhaust particles on bovine brain microvessel endothelial cells. Mol Cell Toxicol 2014. [DOI: 10.1007/s13273-014-0027-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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238
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Jiang X, Chai GS, Wang ZH, Hu Y, Li XG, Ma ZW, Wang Q, Wang JZ, Liu GP. CaMKII-dependent dendrite ramification and spine generation promote spatial training-induced memory improvement in a rat model of sporadic Alzheimer's disease. Neurobiol Aging 2014; 36:867-76. [PMID: 25457025 DOI: 10.1016/j.neurobiolaging.2014.10.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 10/12/2014] [Accepted: 10/13/2014] [Indexed: 01/08/2023]
Abstract
Participation in cognitively stimulating activities can preserve memory capacities in patients with Alzheimer's disease (AD), but the mechanism is not fully understood. Here, we used a rat model with hyperhomocysteinemia, an independent risk factor of AD, to study whether spatial training could remodel the synaptic and/or dendritic plasticity and the key molecular target(s) involved. We found that spatial training in water maze remarkably improved the subsequent short-term and long-term memory performance in contextual fear conditioning and Barnes maze. The trained rats showed an enhanced dendrite ramification, spine generation and plasticity in dentate gyrus (DG) neurons, and stimulation of long-term potentiation between perforant path and DG circuit. Spatial training also increased the levels of postsynaptic GluA1, GluN2A, GluN2B, and PSD93 with selective activation of calcium/calmodulin-dependent protein kinase II (CaMKII), although inhibition of CaMKII by stereotaxic injection of KN93 into hippocampal DG, abolished the training-induced cognitive improvement, dendrite ramification, and spine generation. We conclude that spatial training can preserve the cognitive function by CaMKII-dependent remodeling of dendritic plasticity in hyperhomocysteinemia-induced sporadic AD-like rats.
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Affiliation(s)
- Xia Jiang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China; Department of Pathology, Hubei University of Chinese Medicine, Wuhan, Hubei Province, P. R. China
| | - Gao-Shang Chai
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China; Department of Basic Medicine, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu Province, P. R. China
| | - Zhi-Hao Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China
| | - Yu Hu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China
| | - Xiao-Guang Li
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China
| | - Zhi-Wei Ma
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China
| | - Qun Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China.
| | - Gong-Ping Liu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P. R. China.
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239
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Abstract
Units of dendritic branches called dendritic spines represent more than simply decorative appendages of the neuron and actively participate in integrative functions of “spinous” nerve cells thereby contributing to the general phenomenon of synaptic plasticity. In animal models of drug addiction, spines are profoundly affected by treatments with drugs of abuse and represent important sub cellular markers which interfere deeply into the physiology of the neuron thereby providing an example of the burgeoning and rapidly increasing interest in “structural plasticity”. Medium Spiny Neurons (MSNs) of the Nucleus Accumbens (Nacc) show a reduced number of dendritic spines and a decrease in TH-positive terminals upon withdrawal from opiates, cannabinoids and alcohol. The reduction is localized “strictly” to second order dendritic branches where dopamine (DA)-containing terminals, impinging upon spines, make synaptic contacts. In addition, long-thin spines seems preferentially affected raising the possibility that cellular learning of these neurons may be selectively hampered. These findings suggest that dendritic spines are affected by drugs widely abused by humans and provide yet another example of drug-induced aberrant neural plasticity with marked reflections on the physiology of synapses, system structural organization, and neuronal circuitry remodeling.
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Affiliation(s)
- Saturnino Spiga
- Department of Animal Biology and Ecology, University of Cagliari Cagliari, Italy
| | - Giovanna Mulas
- Department of Animal Biology and Ecology, University of Cagliari Cagliari, Italy ; "G.Minardi" Laboratory of Cognitive Neuroscience, Department of Chemistry and Pharmacy, University of Sassari Sassari, Italy
| | - Francesca Piras
- Department of Animal Biology and Ecology, University of Cagliari Cagliari, Italy ; Department of Natural Science and the Territory, University of Sassari Sassari, Italy
| | - Marco Diana
- "G.Minardi" Laboratory of Cognitive Neuroscience, Department of Chemistry and Pharmacy, University of Sassari Sassari, Italy
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240
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Developmental alterations in anxiety and cognitive behavior in serotonin transporter mutant mice. Psychopharmacology (Berl) 2014; 231:4119-33. [PMID: 24728652 DOI: 10.1007/s00213-014-3554-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE A promoter variant of the serotonin transporter (SERT) gene is known to affect emotional and cognitive regulation. In particular, the "short" allelic variant is implicated in the etiology of multiple neuropsychiatric disorders. Heterozygous (SERT(+/-)) and homozygous (SERT(-/-)) SERT mutant mice are valuable tools for understanding the mechanisms of altered SERT levels. Although these genetic effects are well investigated in adulthood, the developmental trajectory of altered SERT levels for behavior has not been investigated. OBJECTIVES We assessed anxiety-like and cognitive behaviors in SERT mutant mice in early adolescence and adulthood to examine the developmental consequences of reduced SERT levels. Spine density of pyramidal neurons was also measured in corticolimbic brain regions. RESULTS Adult SERT(-/-) mice exhibited increased anxiety-like behavior, but these differences were not observed in early adolescent SERT(-/-) mice. Conversely, SERT(+/-) and SERT(-/-) mice did display higher spontaneous alternation during early adolescence and adulthood. SERT(+/-) and SERT(-/-) also exhibited greater neuronal spine densities in the orbitofrontal but not the medial prefrontal cortices. Adult SERT(-/-) mice also showed an increased spine density in the basolateral amygdala. CONCLUSIONS Developmental alterations of the serotonergic system caused by genetic inactivation of SERT can have different influences on anxiety-like and cognitive behaviors through early adolescence into adulthood, which may be associated with changes of spine density in the prefrontal cortex and amygdala. The altered maturation of serotonergic systems may lead to specific age-related vulnerabilities to psychopathologies that develop during adolescence.
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241
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Russell TA, Blizinsky KD, Cobia DJ, Cahill ME, Xie Z, Sweet RA, Duan J, Gejman PV, Wang L, Csernansky JG, Penzes P. A sequence variant in human KALRN impairs protein function and coincides with reduced cortical thickness. Nat Commun 2014; 5:4858. [PMID: 25224588 PMCID: PMC4166532 DOI: 10.1038/ncomms5858] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 07/31/2014] [Indexed: 12/16/2022] Open
Abstract
Dendritic spine pathology is a key feature of several neuropsychiatric disorders. The Rac1 guanine nucleotide exchange factor kalirin-7 is critical for spine morphogenesis on cortical pyramidal neurons. Here we identify a rare coding variant in the KALRN gene region that encodes the catalytic domain, in a schizophrenia patient and his sibling with major depressive disorder. The D1338N substitution significantly diminished the protein's ability to catalyse the activation of Rac1. Contrary to wild-type kalirin-7, kalirin-7-D1338N failed to increase spine size and density. Both subjects carrying the polymorphism displayed reduced cortical volume in the superior temporal sulcus (STS), a region implicated in schizophrenia. Consistent with this, mice with reduced kalirin expression showed reduced neuropil volume in the rodent homologue of the STS. These data suggest that single amino acid changes in proteins involved in dendritic spine function can have significant effects on the structure and function of the cerebral cortex.
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Affiliation(s)
- Theron A Russell
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - Katherine D Blizinsky
- 1] Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA [2] Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - Derin J Cobia
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - Michael E Cahill
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - Zhong Xie
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - Robert A Sweet
- 1] Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA [2] Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
| | - Jubao Duan
- 1] Department of Psychiatry and Behavioral Sciences, University of Chicago, Chicago, Illinois 60637, USA [2] Department of Psychiatry and Behavioral Sciences, NorthShore University HealthSystem, Evanston, Illinois 60208, USA
| | - Pablo V Gejman
- 1] Department of Psychiatry and Behavioral Sciences, University of Chicago, Chicago, Illinois 60637, USA [2] Department of Psychiatry and Behavioral Sciences, NorthShore University HealthSystem, Evanston, Illinois 60208, USA
| | - Lei Wang
- 1] Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA [2] Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - John G Csernansky
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - Peter Penzes
- 1] Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA [2] Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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242
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Santos AR, Kanellopoulos AK, Bagni C. Learning and behavioral deficits associated with the absence of the fragile X mental retardation protein: what a fly and mouse model can teach us. ACTA ACUST UNITED AC 2014; 21:543-55. [PMID: 25227249 PMCID: PMC4175497 DOI: 10.1101/lm.035956.114] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The Fragile X syndrome (FXS) is the most frequent form of inherited mental disability and is considered a monogenic cause of autism spectrum disorder. FXS is caused by a triplet expansion that inhibits the expression of the FMR1 gene. The gene product, the Fragile X Mental Retardation Protein (FMRP), regulates mRNA metabolism in brain and nonneuronal cells. During brain development, FMRP controls the expression of key molecules involved in receptor signaling, cytoskeleton remodeling, protein synthesis and, ultimately, spine morphology. Symptoms associated with FXS include neurodevelopmental delay, cognitive impairment, anxiety, hyperactivity, and autistic-like behavior. Twenty years ago the first Fmr1 KO mouse to study FXS was generated, and several years later other key models including the mutant Drosophila melanogaster, dFmr1, have further helped the understanding of the cellular and molecular causes behind this complex syndrome. Here, we review to which extent these biological models are affected by the absence of FMRP, pointing out the similarities with the observed human dysfunction. Additionally, we discuss several potential treatments under study in animal models that are able to partially revert some of the FXS abnormalities.
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Affiliation(s)
- Ana Rita Santos
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium Center for Human Genetics, KU Leuven, 3000 Leuven, Belgium Leuven Institute for Neurodegenerative Diseases (LIND), KU Leuven, 3000 Leuven, Belgium
| | - Alexandros K Kanellopoulos
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium Center for Human Genetics, KU Leuven, 3000 Leuven, Belgium Leuven Institute for Neurodegenerative Diseases (LIND), KU Leuven, 3000 Leuven, Belgium
| | - Claudia Bagni
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium Center for Human Genetics, KU Leuven, 3000 Leuven, Belgium Leuven Institute for Neurodegenerative Diseases (LIND), KU Leuven, 3000 Leuven, Belgium Department of Biomedicine and Prevention, University of Rome "Tor Vergata" 00133, Rome, Italy
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243
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Xu X, Miller EC, Pozzo-Miller L. Dendritic spine dysgenesis in Rett syndrome. Front Neuroanat 2014; 8:97. [PMID: 25309341 PMCID: PMC4159975 DOI: 10.3389/fnana.2014.00097] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 08/25/2014] [Indexed: 11/13/2022] Open
Abstract
Spines are small cytoplasmic extensions of dendrites that form the postsynaptic compartment of the majority of excitatory synapses in the mammalian brain. Alterations in the numerical density, size, and shape of dendritic spines have been correlated with neuronal dysfunction in several neurological and neurodevelopmental disorders associated with intellectual disability, including Rett syndrome (RTT). RTT is a progressive neurodevelopmental disorder associated with intellectual disability that is caused by loss of function mutations in the transcriptional regulator methyl CpG-binding protein 2 (MECP2). Here, we review the evidence demonstrating that principal neurons in RTT individuals and Mecp2-based experimental models exhibit alterations in the number and morphology of dendritic spines. We also discuss the exciting possibility that signaling pathways downstream of brain-derived neurotrophic factor (BDNF), which is transcriptionally regulated by MeCP2, offer promising therapeutic options for modulating dendritic spine development and plasticity in RTT and other MECP2-associated neurodevelopmental disorders.
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Affiliation(s)
- Xin Xu
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
| | - Eric C Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
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244
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Karasawa T, Lombroso PJ. Disruption of striatal-enriched protein tyrosine phosphatase (STEP) function in neuropsychiatric disorders. Neurosci Res 2014; 89:1-9. [PMID: 25218562 DOI: 10.1016/j.neures.2014.08.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 08/12/2014] [Accepted: 08/21/2014] [Indexed: 10/24/2022]
Abstract
Striatal-enriched protein tyrosine phosphatase (STEP) is a brain-specific tyrosine phosphatase that plays a major role in the development of synaptic plasticity. Recent findings have implicated STEP in several psychiatric and neurological disorders, including Alzheimer's disease, schizophrenia, fragile X syndrome, Huntington's disease, stroke/ischemia, and stress-related psychiatric disorders. In these disorders, STEP protein expression levels and activity are dysregulated, contributing to the cognitive deficits that are present. In this review, we focus on the most recent findings on STEP, discuss how STEP expression and activity are maintained during normal cognitive function, and how disruptions in STEP activity contribute to a number of illnesses.
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Affiliation(s)
- Takatoshi Karasawa
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi 480-0392, Japan.
| | - Paul J Lombroso
- Departments of Neurobiology, Psychiatry and Child Study Center, Yale University School of Medicine, New Haven, CT 06520, USA
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245
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Risher WC, Ustunkaya T, Singh Alvarado J, Eroglu C. Rapid Golgi analysis method for efficient and unbiased classification of dendritic spines. PLoS One 2014; 9:e107591. [PMID: 25208214 PMCID: PMC4160288 DOI: 10.1371/journal.pone.0107591] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/20/2014] [Indexed: 11/18/2022] Open
Abstract
Dendritic spines are the primary recipients of excitatory synaptic input in the brain. Spine morphology provides important information on the functional state of ongoing synaptic transmission. One of the most commonly used methods to visualize spines is Golgi-Cox staining, which is appealing both due to ease of sample preparation and wide applicability to multiple species including humans. However, the classification of spines is a time-consuming and often expensive task that yields widely varying results between individuals. Here, we present a novel approach to this analysis technique that uses the unique geometry of different spine shapes to categorize spines on a purely objective basis. This rapid Golgi spine analysis method successfully conveyed the maturational shift in spine types during development in the mouse primary visual cortex. This approach, built upon freely available software, can be utilized by researchers studying a broad range of synaptic connectivity phenotypes in both development and disease.
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Affiliation(s)
- W. Christopher Risher
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Tuna Ustunkaya
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jonnathan Singh Alvarado
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Institute for Brain Sciences, Durham, North Carolina, United States of America
- * E-mail:
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246
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Chen G, Hu T, Li Q, Li J, Jia Y, Wang Z. Expression of synaptosomal-associated protein-25 in the rat brain after subarachnoid hemorrhage. Neural Regen Res 2014; 8:2693-702. [PMID: 25206580 PMCID: PMC4145993 DOI: 10.3969/j.issn.1673-5374.2013.29.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/09/2013] [Indexed: 11/18/2022] Open
Abstract
Synaptosomal-associated protein-25 is an important factor for synaptic functions and cognition. In this study, subarachnoid hemorrhage models with spatial learning disorder were established through a blood injection into the chiasmatic cistern. Immunohistochemical staining and western blot analysis results showed that synaptosomal-associated protein-25 expression in the temporal lobe, hippocampus, and cerebellum significantly lower at days 1 and 3 following subarachnoid morrhage. Our findings indicate that synaptosomal-associated protein-25 expression was down-regulated in the rat brain after subarachnoid hemorrhage.
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Affiliation(s)
- Gang Chen
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Tong Hu
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China ; Department of Neurosurgery, Yixing People's Hospital, Yixing 214200, Jiangsu Province, China
| | - Qi Li
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Jianke Li
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Yang Jia
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Zhong Wang
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
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247
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Koth AP, Oliveira BR, Parfitt GM, Buonocore JDQ, Barros DM. Participation of group I p21-activated kinases in neuroplasticity. ACTA ACUST UNITED AC 2014; 108:270-7. [PMID: 25174326 DOI: 10.1016/j.jphysparis.2014.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/25/2014] [Accepted: 08/20/2014] [Indexed: 12/15/2022]
Abstract
PAKs are a family of serine/threonine protein kinases activated by small GTPases of the Rho family, including Rac and Cdc42, and are categorized into group I (isoforms 1, 2 and 3) and group II (isoforms 4, 5 and 6). PAK1 and PAK3 are critically involved in biological mechanisms associated with neurodevelopment, neuroplasticity and maturation of the nervous system, and changes in their activity have been detected in pathological disorders, such as Alzheimer's disease, Huntington's disease and mental retardation. The group I PAKs have been associated with neurological processes due to their involvement in intracellular mechanisms that result in molecular and cellular morphological alterations that promote cytoskeletal outgrowth, increasing the efficiency of synaptic transmission. Their substrates in these processes include other intracellular signaling molecules, such as Raf, Mek and LIMK, as well as other components of the cytoskeleton, such as MLC and FLNa. In this review, we describe the characteristics of group I PAKs, such as their molecular structure, mechanisms of activation and importance in the neurobiological processes involved in synaptic plasticity.
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Affiliation(s)
- André P Koth
- Instituto de Ciências Biológicas (ICB), Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Laboratório de Neurociências, Universidade Federal do Rio Grande (FURG), Av Itália, Km 8, Rio Grande, RS 96203-900, Brazil.
| | - Bruno R Oliveira
- Instituto de Ciências Biológicas (ICB), Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Laboratório de Biologia Molecular, Universidade Federal do Rio Grande (FURG), Av Itália, Km 8, Rio Grande, RS 96203-900, Brazil.
| | - Gustavo M Parfitt
- Instituto de Ciências Biológicas (ICB), Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Laboratório de Neurociências, Universidade Federal do Rio Grande (FURG), Av Itália, Km 8, Rio Grande, RS 96203-900, Brazil.
| | - Juliana de Quadros Buonocore
- Instituto de Ciências Biológicas (ICB), Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Laboratório de Neurociências, Universidade Federal do Rio Grande (FURG), Av Itália, Km 8, Rio Grande, RS 96203-900, Brazil.
| | - Daniela M Barros
- Instituto de Ciências Biológicas (ICB), Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Laboratório de Neurociências, Universidade Federal do Rio Grande (FURG), Av Itália, Km 8, Rio Grande, RS 96203-900, Brazil.
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Posada-Duque RA, Barreto GE, Cardona-Gomez GP. Protection after stroke: cellular effectors of neurovascular unit integrity. Front Cell Neurosci 2014; 8:231. [PMID: 25177270 PMCID: PMC4132372 DOI: 10.3389/fncel.2014.00231] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/24/2014] [Indexed: 12/16/2022] Open
Abstract
Neurological disorders are prevalent worldwide. Cerebrovascular diseases (CVDs), which account for 55% of all neurological diseases, are the leading cause of permanent disability, cognitive and motor disorders and dementia. Stroke affects the function and structure of blood-brain barrier, the loss of cerebral blood flow regulation, oxidative stress, inflammation and the loss of neural connections. Currently, no gold standard treatments are available outside the acute therapeutic window to improve outcome in stroke patients. Some promising candidate targets have been identified for the improvement of long-term recovery after stroke, such as Rho GTPases, cell adhesion proteins, kinases, and phosphatases. Previous studies by our lab indicated that Rho GTPases (Rac and RhoA) are involved in both tissue damage and survival, as these proteins are essential for the morphology and movement of neurons, astrocytes and endothelial cells, thus playing a critical role in the balance between cell survival and death. Treatment with a pharmacological inhibitor of RhoA/ROCK blocks the activation of the neurodegeneration cascade. In addition, Rac and synaptic adhesion proteins (p120 catenin and N-catenin) play critical roles in protection against cerebral infarction and in recovery by supporting the neurovascular unit and cytoskeletal remodeling activity to maintain the integrity of the brain parenchyma. Interestingly, neuroprotective agents, such as atorvastatin, and CDK5 silencing after cerebral ischemia and in a glutamate-induced excitotoxicity model may act on the same cellular effectors to recover neurovascular unit integrity. Therefore, future efforts must focus on individually targeting the structural and functional roles of each effector of neurovascular unit and the interactions in neural and non-neural cells in the post-ischemic brain and address how to promote the recovery or prevent the loss of homeostasis in the short, medium and long term.
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Affiliation(s)
- Rafael Andres Posada-Duque
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana Bogotá D.C., Colombia
| | - Gloria Patricia Cardona-Gomez
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia UdeA Medellín, Colombia
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249
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Branching angles of pyramidal cell dendrites follow common geometrical design principles in different cortical areas. Sci Rep 2014; 4:5909. [PMID: 25081193 PMCID: PMC4118193 DOI: 10.1038/srep05909] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 06/27/2014] [Indexed: 12/03/2022] Open
Abstract
Unraveling pyramidal cell structure is crucial to understanding cortical circuit computations. Although it is well known that pyramidal cell branching structure differs in the various cortical areas, the principles that determine the geometric shapes of these cells are not fully understood. Here we analyzed and modeled with a von Mises distribution the branching angles in 3D reconstructed basal dendritic arbors of hundreds of intracellularly injected cortical pyramidal cells in seven different cortical regions of the frontal, parietal, and occipital cortex of the mouse. We found that, despite the differences in the structure of the pyramidal cells in these distinct functional and cytoarchitectonic cortical areas, there are common design principles that govern the geometry of dendritic branching angles of pyramidal cells in all cortical areas.
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250
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Coiro P, Stoenica L, Strauss U, Bräuer AU. Plasticity-related gene 5 promotes spine formation in murine hippocampal neurons. J Biol Chem 2014; 289:24956-70. [PMID: 25074937 DOI: 10.1074/jbc.m114.597880] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transmembrane protein plasticity-related genes 3 and 5 (PRG3 and PRG5) increase filopodial formation in various cell lines, independently of Cdc42. However, information on the effects of PRG5 during neuronal development is sparse. Here, we present several lines of evidence for the involvement of PRG5 in the genesis and stabilization of dendritic spines. First, PRG5 was strongly expressed during mouse brain development from embryonic day 14 (E14), peaked around the time of birth, and remained stable at least until early adult stages (i.e. P30). Second, on a subcellular level, PRG5 expression shifted from an equal distribution along all neurites toward accumulation only along dendrites during hippocampal development in vitro. Third, overexpression of PRG5 in immature hippocampal neurons induced formation of spine-like structures ahead of time. Proper amino acid sequences in the extracellular domains (D1 to D3) of PRG5 were a prerequisite for trafficking and induction of spine-like structures, as shown by mutation analysis. Fourth, at stages when spines are present, knockdown of PRG5 reduced the number but not the length of protrusions. This was accompanied by a decrease in the number of excitatory synapses and, consequently, by a reduction of miniature excitatory postsynaptic current frequencies, although miniature excitatory postsynaptic current amplitudes remained similar. In turn, overexpressing PRG5 in mature neurons not only increased Homer-positive spine numbers but also augmented spine head diameters. Mechanistically, PRG5 interacts with phosphorylated phosphatidylinositols, phospholipids involved in dendritic spine formation by different lipid-protein assays. Taken together, our data propose that PRG5 promotes spine formation.
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Affiliation(s)
- Pierluca Coiro
- From the Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Luminita Stoenica
- From the Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Ulf Strauss
- From the Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Anja Ursula Bräuer
- From the Institute of Cell Biology and Neurobiology, Center for Anatomy, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
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