1
|
CPG15/Neuritin Mimics Experience in Selecting Excitatory Synapses for Stabilization by Facilitating PSD95 Recruitment. Cell Rep 2020; 28:1584-1595.e5. [PMID: 31390571 PMCID: PMC6740334 DOI: 10.1016/j.celrep.2019.07.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/11/2019] [Accepted: 07/02/2019] [Indexed: 11/24/2022] Open
Abstract
A key feature of brain plasticity is the experience-dependent selection of optimal connections· implemented by a set of activity-regulated genes that dynamically adjust synapse strength and number. The activity-regulated gene cpg15/neuritin has been previously implicated in stabilization and maturation of excitatory synapses. Here· we combine two-photon microscopy with genetic and sensory manipulations to dissect excitatory synapse formation in vivo and examine the role of activity and CPG15 in dendritic spine formation, PSD95 recruitment, and synapse stabilization. We find that neither visual experience nor CPG15 is required for spine formation. However, PSD95 recruitment to nascent spines and their subsequent stabilization requires both. Further, cell-autonomous CPG15 expression is sufficient to replace experience in facilitating PSD95 recruitment and spine stabilization. CPG15 directly interacts with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors on immature dendritic spines, suggesting a signaling mode for this small extracellular molecule acting as an experience-dependent “selector” for spine stabilization and synapse maturation. Experience plays a key role in formation and continuous optimization of brain circuits. Subramanian et al. show that the molecule CPG15/neuritin can replace experience in selecting which nascent contacts between neurons are retained, facilitating the recruitment of proteins that promote synapse maturation and stabilization.
Collapse
|
2
|
Runge K, Cardoso C, de Chevigny A. Dendritic Spine Plasticity: Function and Mechanisms. Front Synaptic Neurosci 2020. [DOI: 10.3389/fnsyn.2020.00036
expr 823669561 + 872784217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
|
3
|
Runge K, Cardoso C, de Chevigny A. Dendritic Spine Plasticity: Function and Mechanisms. Front Synaptic Neurosci 2020; 12:36. [PMID: 32982715 PMCID: PMC7484486 DOI: 10.3389/fnsyn.2020.00036] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/28/2020] [Indexed: 12/12/2022] Open
Abstract
Dendritic spines are small protrusions studding neuronal dendrites, first described in 1888 by Ramón y Cajal using his famous Golgi stainings. Around 50 years later the advance of electron microscopy (EM) confirmed Cajal's intuition that spines constitute the postsynaptic site of most excitatory synapses in the mammalian brain. The finding that spine density decreases between young and adult ages in fixed tissues suggested that spines are dynamic. It is only a decade ago that two-photon microscopy (TPM) has unambiguously proven the dynamic nature of spines, through the repeated imaging of single spines in live animals. Spine dynamics comprise formation, disappearance, and stabilization of spines and are modulated by neuronal activity and developmental age. Here, we review several emerging concepts in the field that start to answer the following key questions: What are the external signals triggering spine dynamics and the molecular mechanisms involved? What is, in return, the role of spine dynamics in circuit-rewiring, learning, and neuropsychiatric disorders?
Collapse
Affiliation(s)
- Karen Runge
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
| | - Carlos Cardoso
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
| | - Antoine de Chevigny
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
| |
Collapse
|
4
|
Synaptic and circuit development of the primary sensory cortex. Exp Mol Med 2018; 50:1-9. [PMID: 29628505 PMCID: PMC5938038 DOI: 10.1038/s12276-018-0029-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/06/2017] [Indexed: 01/06/2023] Open
Abstract
Animals, including humans, optimize their primary sensory cortex through the use of input signals, which allow them to adapt to the external environment and survive. The time window at the beginning of life in which external input signals are connected sensitively and strongly to neural circuit optimization is called the critical period. The critical period has attracted the attention of many neuroscientists due to the rapid activity-/experience-dependent circuit development that occurs, which is clearly differentiated from other developmental time periods and brain areas. This process involves various types of GABAergic inhibitory neurons, the extracellular matrix, neuromodulators, transcription factors, and neurodevelopmental factors. In this review, I discuss recent progress regarding the biological nature of the critical period that contribute to a better understanding of brain development.
Collapse
|
5
|
Zhang P, Luo X, Guo Z, Xiong A, Dong H, Zhang Q, Liu C, Zhu J, Wang H, Yu N, Zhang J, Hong Y, Yang L, Huang J. Neuritin Inhibits Notch Signaling through Interacted with Neuralized to Promote the Neurite Growth. Front Mol Neurosci 2017. [PMID: 28642682 PMCID: PMC5462965 DOI: 10.3389/fnmol.2017.00179] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neuritin plays a key role in neural development and regeneration by promoting neurite outgrowth and synapse maturation. However, the mechanism of neuritin in modulating neurite growth has not been elucidated. Here, using yeast two-hybrid we screened and discovered the interaction of neuritin and neuralized (NEURL1), which is an important regulator that can activate Notch signaling through promoting endocytosis of Notch ligand. And then we identified the interaction of neuritin and neuralized by co-immunoprecipitation (IP) assays, and clarified that neuritin and NEURL1 were co-localized on the cell membrane of SH-SY5Y cells. Moreover, neuritin significantly suppressed Notch ligand Jagged1 (JAG1) endocytosis promoted by NEURL1, and then inhibited the activation of Notch receptor Notch intracellular domain (NICD) and decreased the expression of downstream gene hairy and enhancer of split-1 (HES1). Importantly, the effect of neuritin on inhibiting Notch signaling was rescued by NEURL1, which indicated that neuritin is an upstream and negative regulator of NEURL1 to inhibit Notch signaling through interaction with NEURL1. Notably, recombinant neuritin restored the retraction of neurites caused by activation of Notch, and neurite growth stimulated by neuritin was partially blocked by NEURL1. These findings establish neuritin as an upstream and negative regulator of NEURL1 that inhibits Notch signaling to promote neurite growth. This mechanism connects neuritin with Notch signaling, and provides a valuable foundation for further investigation of neuritin's role in neurodevelopment and neural plasticity.
Collapse
Affiliation(s)
- Pan Zhang
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Xing Luo
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Zheng Guo
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Anying Xiong
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Hongchang Dong
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Qiao Zhang
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Chunyan Liu
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Jingling Zhu
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Haiyan Wang
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Na Yu
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Jinli Zhang
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| | - Yu Hong
- School of Medicine, Hangzhou Normal UniversityHangzhou, China
| | - Lei Yang
- School of Medicine, Hangzhou Normal UniversityHangzhou, China
| | - Jin Huang
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Department of Biochemistry, Shihezi University School of MedicineShihezi, China
| |
Collapse
|
6
|
Leijon SC, Peyda S, Magnusson AK. Temporal processing capacity in auditory-deprived superior paraolivary neurons is rescued by sequential plasticity during early development. Neuroscience 2016; 337:315-330. [DOI: 10.1016/j.neuroscience.2016.09.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 09/01/2016] [Accepted: 09/09/2016] [Indexed: 01/04/2023]
|
7
|
Li Y, Tang J, Zhang Y, Wang H, Yuan W, Yu N, Luo X, Xu X, Huang J, Yang L. The cloning, expression and purification of recombinant human neuritin from Escherichia coli and the partial analysis of its neurobiological activity. Cell Mol Biol Lett 2016; 20:965-73. [PMID: 26751893 DOI: 10.1515/cmble-2015-0057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/31/2015] [Indexed: 11/15/2022] Open
Abstract
Neuritin (Nrn1) is a neurotrophic factor that plays various roles in neural development and synaptic plasticity. In this study, the NRN1 gene was cloned and expressed in Escherichia coli and then recombinant neuritin protein was purified so that its neurobiological activity could be evaluated. The protein, which was obtained at a concentration of 0.45 mg/ml and > 90% purity, had the predicted molecular weight of 30 kDa, as determined via sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Western blot analysis confirmed that an anti-neuritin antibody could recognize the fusion protein. Subsequent functional analyses revealed that recombinant neuritin promoted neurite outgrowth in embryonic chicken dorsal root ganglia and PC12 cells. These results suggest that recombinant neuritin protein could be a valuable tool for inducing neurite regeneration, for instance in cases of spinal cord injury or neurological diseases.
Collapse
|
8
|
Coullon GSL, Emir UE, Fine I, Watkins KE, Bridge H. Neurochemical changes in the pericalcarine cortex in congenital blindness attributable to bilateral anophthalmia. J Neurophysiol 2015; 114:1725-33. [PMID: 26180125 DOI: 10.1152/jn.00567.2015] [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: 06/09/2015] [Accepted: 07/15/2015] [Indexed: 01/22/2023] Open
Abstract
Congenital blindness leads to large-scale functional and structural reorganization in the occipital cortex, but relatively little is known about the neurochemical changes underlying this cross-modal plasticity. To investigate the effect of complete and early visual deafferentation on the concentration of metabolites in the pericalcarine cortex, (1)H magnetic resonance spectroscopy was performed in 14 sighted subjects and 5 subjects with bilateral anophthalmia, a condition in which both eyes fail to develop. In the pericalcarine cortex, where primary visual cortex is normally located, the proportion of gray matter was significantly greater, and levels of choline, glutamate, glutamine, myo-inositol, and total creatine were elevated in anophthalmic relative to sighted subjects. Anophthalmia had no effect on the structure or neurochemistry of a sensorimotor cortex control region. More gray matter, combined with high levels of choline and myo-inositol, resembles the profile of the cortex at birth and suggests that the lack of visual input from the eyes might have delayed or arrested the maturation of this cortical region. High levels of choline and glutamate/glutamine are consistent with enhanced excitatory circuits in the anophthalmic occipital cortex, which could reflect a shift toward enhanced plasticity or sensitivity that could in turn mediate or unmask cross-modal responses. Finally, it is possible that the change in function of the occipital cortex results in biochemical profiles that resemble those of auditory, language, or somatosensory cortex.
Collapse
Affiliation(s)
- Gaelle S L Coullon
- Functional MRI of the Brain Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Uzay E Emir
- Functional MRI of the Brain Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Ione Fine
- Department of Psychology, University of Washington, Seattle, Washington
| | - Kate E Watkins
- Functional MRI of the Brain Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom; Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Holly Bridge
- Functional MRI of the Brain Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom;
| |
Collapse
|
9
|
Expression and purification of recombinant human neuritin from Pichia pastoris and a partial analysis of its neurobiological activity in vitro. Appl Microbiol Biotechnol 2015; 99:8035-43. [DOI: 10.1007/s00253-015-6649-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/24/2015] [Accepted: 04/26/2015] [Indexed: 11/27/2022]
|
10
|
Sharma TP, Liu Y, Wordinger RJ, Pang IH, Clark AF. Neuritin 1 promotes retinal ganglion cell survival and axonal regeneration following optic nerve crush. Cell Death Dis 2015; 6:e1661. [PMID: 25719245 PMCID: PMC4669798 DOI: 10.1038/cddis.2015.22] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 12/11/2014] [Accepted: 01/06/2015] [Indexed: 12/16/2022]
Abstract
Neuritin 1 (Nrn1) is an extracellular glycophosphatidylinositol-linked protein that stimulates axonal plasticity, dendritic arborization and synapse maturation in the central nervous system (CNS). The purpose of this study was to evaluate the neuroprotective and axogenic properties of Nrn1 on axotomized retinal ganglion cells (RGCs) in vitro and on the in vivo optic nerve crush (ONC) mouse model. Axotomized cultured RGCs treated with recombinant hNRN1 significantly increased survival of RGCs by 21% (n=6–7, P<0.01) and neurite outgrowth in RGCs by 141% compared to controls (n=15, P<0.05). RGC transduction with AAV2-CAG–hNRN1 prior to ONC promoted RGC survival (450%, n=3–7, P<0.05) and significantly preserved RGC function by 70% until 28 days post crush (dpc) (n=6, P<0.05) compared with the control AAV2-CAG–green fluorescent protein transduction group. Significantly elevated levels of RGC marker, RNA binding protein with multiple splicing (Rbpms; 73%, n=5–8, P<0.001) and growth cone marker, growth-associated protein 43 (Gap43; 36%, n=3, P<0.01) were observed 28 dpc in the retinas of the treatment group compared with the control group. Significant increase in Gap43 (100%, n=5–6, P<0.05) expression was observed within the optic nerves of the AAV2–hNRN1 group compared to controls. In conclusion, Nrn1 exhibited neuroprotective, regenerative effects and preserved RGC function on axotomized RGCs in vitro and after axonal injury in vivo. Nrn1 is a potential therapeutic target for CNS neurodegenerative diseases.
Collapse
Affiliation(s)
- T P Sharma
- 1] North Texas Eye Research Institute, University of North Texas Health Science Center, Ft. Worth, TX 76107, USA [2] Department of Cell Biology & Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Y Liu
- 1] North Texas Eye Research Institute, University of North Texas Health Science Center, Ft. Worth, TX 76107, USA [2] Department of Cell Biology & Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - R J Wordinger
- 1] North Texas Eye Research Institute, University of North Texas Health Science Center, Ft. Worth, TX 76107, USA [2] Department of Cell Biology & Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - I-H Pang
- 1] North Texas Eye Research Institute, University of North Texas Health Science Center, Ft. Worth, TX 76107, USA [2] Department of Pharmaceutical Sciences, College of Pharmacy, University of North Texas Health Science Center, Ft. Worth, TX 76107, USA
| | - A F Clark
- 1] North Texas Eye Research Institute, University of North Texas Health Science Center, Ft. Worth, TX 76107, USA [2] Department of Cell Biology & Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| |
Collapse
|
11
|
Neuritin can normalize neural deficits of Alzheimer's disease. Cell Death Dis 2014; 5:e1523. [PMID: 25393479 PMCID: PMC4260736 DOI: 10.1038/cddis.2014.478] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 10/05/2014] [Accepted: 10/09/2014] [Indexed: 12/15/2022]
Abstract
Reductions in hippocampal neurite complexity and synaptic plasticity are believed to contribute to the progressive impairment in episodic memory and the mild cognitive decline that occur particularly in the early stages of Alzheimer's disease (AD). Despite the functional and therapeutic importance for patients with AD, intervention to rescue or normalize dendritic elaboration and synaptic plasticity is scarcely provided. Here we show that overexpression of neuritin, an activity-dependent protein, promoted neurite outgrowth and maturation of synapses in parallel with enhanced basal synaptic transmission in cultured hippocampal neurons. Importantly, exogenous application of recombinant neuritin fully restored dendritic complexity as well as spine density in hippocampal neurons prepared from Tg2576 mice, whereas it did not affect neurite branching of neurons from their wild-type littermates. We also showed that soluble recombinant neuritin, when chronically infused into the brains of Tg2576 mice, normalized synaptic plasticity in acute hippocampal slices, leading to intact long-term potentiation. By revealing the protective actions of soluble neuritin against AD-related neural defects, we provide a potential therapeutic approach for patients with AD.
Collapse
|
12
|
Gao R, Wang L, Sun J, Nie K, Jian H, Gao L, Liao X, Zhang H, Huang J, Gan S. MiR-204 promotes apoptosis in oxidative stress-induced rat Schwann cells by suppressing neuritin
expression. FEBS Lett 2014; 588:3225-32. [DOI: 10.1016/j.febslet.2014.07.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/29/2014] [Accepted: 07/06/2014] [Indexed: 02/04/2023]
|
13
|
Ghiretti AE, Paradis S. Molecular mechanisms of activity-dependent changes in dendritic morphology: role of RGK proteins. Trends Neurosci 2014; 37:399-407. [PMID: 24910262 PMCID: PMC4113564 DOI: 10.1016/j.tins.2014.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 01/10/2023]
Abstract
The nervous system has the amazing capacity to transform sensory experience from the environment into changes in neuronal activity that, in turn, cause long-lasting alterations in neuronal morphology. Recent findings indicate that, surprisingly, sensory experience concurrently activates molecular signaling pathways that both promote and inhibit dendritic complexity. Historically, a number of positive regulators of activity-dependent dendritic complexity have been described, whereas the list of identified negative regulators of this process is much shorter. In recent years, there has been an emerging appreciation of the importance of the Rad/Rem/Rem2/Gem/Kir (RGK) GTPases as mediators of activity-dependent structural plasticity. In the following review, we discuss the traditional view of RGK proteins, as well as our evolving understanding of the role of these proteins in instructing structural plasticity.
Collapse
Affiliation(s)
- Amy E Ghiretti
- Department of Biology, National Center for Behavioral Genomics, and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
| | - Suzanne Paradis
- Department of Biology, National Center for Behavioral Genomics, and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA.
| |
Collapse
|
14
|
Veraart C, Duret F, Brelén M, Oozeer M, Delbeke J. Vision rehabilitation in the case of blindness. Expert Rev Med Devices 2014; 1:139-53. [PMID: 16293017 DOI: 10.1586/17434440.1.1.139] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This article examines the various vision rehabilitation procedures that are available for early and late blindness. Depending on the pathology involved, several vision rehabilitation procedures exist, or are in development. Visual aids are available for low vision individuals, as are sensory aids for blind persons. Most noninvasive sensory substitution prostheses as well as implanted visual prostheses in development are reviewed. Issues dealing with vision rehabilitation are also discussed, such as problems of biocompatibility, electrical safety, psychosocial aspects, and ethics. Basic studies devoted to vision rehabilitation such as simulation in mathematical models and simulation of artificial vision are also presented. Finally, the importance of accurate rehabilitation assessment is addressed, and tentative market figures are given.
Collapse
Affiliation(s)
- Claude Veraart
- Neural Rehabilitation Engineering Laboratory, Universite catholique de Louvain, 54 Avenue Hippocrate Box UCL-54.46, B-1200 Brussels, Belgium.
| | | | | | | | | |
Collapse
|
15
|
Zito A, Cartelli D, Cappelletti G, Cariboni A, Andrews W, Parnavelas J, Poletti A, Galbiati M. Neuritin 1 promotes neuronal migration. Brain Struct Funct 2012; 219:105-18. [DOI: 10.1007/s00429-012-0487-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/16/2012] [Indexed: 11/30/2022]
|
16
|
Fujino T, Leslie JH, Eavri R, Chen JL, Lin WC, Flanders GH, Borok E, Horvath TL, Nedivi E. CPG15 regulates synapse stability in the developing and adult brain. Genes Dev 2012; 25:2674-85. [PMID: 22190461 DOI: 10.1101/gad.176172.111] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Use-dependent selection of optimal connections is a key feature of neural circuit development and, in the mature brain, underlies functional adaptation, such as is required for learning and memory. Activity patterns guide circuit refinement through selective stabilization or elimination of specific neuronal branches and synapses. The molecular signals that mediate activity-dependent synapse and arbor stabilization and maintenance remain elusive. We report that knockout of the activity-regulated gene cpg15 in mice delays developmental maturation of axonal and dendritic arbors visualized by anterograde tracing and diolistic labeling, respectively. Electrophysiology shows that synaptic maturation is also delayed, and electron microscopy confirms that many dendritic spines initially lack functional synaptic contacts. While circuits eventually develop, in vivo imaging reveals that spine maintenance is compromised in the adult, leading to a gradual attrition in spine numbers. Loss of cpg15 also results in poor learning. cpg15 knockout mice require more trails to learn, but once they learn, memories are retained. Our findings suggest that CPG15 acts to stabilize active synapses on dendritic spines, resulting in selective spine and arbor stabilization and synaptic maturation, and that synapse stabilization mediated by CPG15 is critical for efficient learning.
Collapse
Affiliation(s)
- Tadahiro Fujino
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Gabbott PL, Stewart MG. Visual deprivation alters dendritic bundle architecture in layer 4 of rat visual cortex. Neuroscience 2012; 207:65-77. [PMID: 22269141 DOI: 10.1016/j.neuroscience.2012.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 12/23/2011] [Accepted: 01/03/2012] [Indexed: 10/14/2022]
Abstract
The effect of visual deprivation followed by light exposure on the tangential organisation of dendritic bundles passing through layer 4 of the rat visual cortex was studied quantitatively in the light microscope. Four groups of animals were investigated: (I) rats reared in an environment illuminated normally--group 52 dL; (II) rats reared in the dark until 21 days postnatum (DPN) and subsequently light exposed for 31 days-group 21/31; (III) rats dark reared until 52 DPN and then subsequently light exposed for 3 days--group 3 dL; and (IV) rats totally dark reared until 52 DPN--group 52 DPN. Each group contained five animals. Semithin 0.5-1-μm thick resin-embedded sections were collected from tangential sampling levels through the middle of layer 4 in area 17 and stained with Toluidine Blue. These sections were used to quantitatively analyse the composition and distribution of dendritic clusters in the tangential plane. The key result of this study indicates a significant reduction in the mean number of medium- and small-sized dendritic profiles (diameter less than 2 μm) contributing to clusters in layer 4 of groups 3 dL and 52 dD compared with group 21/31. No differences were detected in the mean number of large-sized dendritic profiles composing a bundle in these experimental groups. Moreover, the mean number of clusters and their tangential distribution in layer 4 did not vary significantly between all four groups. Finally, the clustering parameters were not significantly different between groups 21/31 and the normally reared group 52 dL. This study demonstrates, for the first time, that extended periods of dark rearing followed by light exposure can alter the morphological composition of dendritic bundles in thalamorecipient layer 4 of rat visual cortex. Because these changes occur in the primary region of thalamocortical input, they may underlie specific alterations in the processing of visual information both cortically and subcortically during periods of dark rearing and light exposure.
Collapse
Affiliation(s)
- P L Gabbott
- Brain and Behaviour Discipline, Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes MK7 6AA, UK.
| | | |
Collapse
|
18
|
El-Sayed M, Hofman-Bang J, Mikkelsen JD. Effect of brain-derived neurotrophic factor on activity-regulated cytoskeleton-associated protein gene expression in primary frontal cortical neurons. Comparison with NMDA and AMPA. Eur J Pharmacol 2011; 660:351-7. [DOI: 10.1016/j.ejphar.2011.03.055] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 03/09/2011] [Accepted: 03/28/2011] [Indexed: 10/18/2022]
|
19
|
Leslie JH, Nedivi E. Activity-regulated genes as mediators of neural circuit plasticity. Prog Neurobiol 2011; 94:223-37. [PMID: 21601615 DOI: 10.1016/j.pneurobio.2011.05.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 05/03/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
Modifications of neuronal circuits allow the brain to adapt and change with experience. This plasticity manifests during development and throughout life, and can be remarkably long lasting. Evidence has linked activity-regulated gene expression to the long-term structural and electrophysiological adaptations that take place during developmental critical periods, learning and memory, and alterations to sensory map representations in the adult. In all these cases, the cellular response to neuronal activity integrates multiple tightly coordinated mechanisms to precisely orchestrate long-lasting, functional and structural changes in brain circuits. Experience-dependent plasticity is triggered when neuronal excitation activates cellular signaling pathways from the synapse to the nucleus that initiate new programs of gene expression. The protein products of activity-regulated genes then work via a diverse array of cellular mechanisms to modify neuronal functional properties. Synaptic strengthening or weakening can reweight existing circuit connections, while structural changes including synapse addition and elimination create new connections. Posttranscriptional regulatory mechanisms, often also dependent on activity, further modulate activity-regulated gene transcript and protein function. Thus, activity-regulated genes implement varied forms of structural and functional plasticity to fine-tune brain circuit wiring.
Collapse
Affiliation(s)
- Jennifer H Leslie
- Department of Biology, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | | |
Collapse
|
20
|
Chandler D, Dragović M, Cooper M, Badcock JC, Mullin BH, Faulkner D, Wilson SG, Hallmayer J, Howell S, Rock D, Palmer LJ, Kalaydjieva L, Jablensky A. Impact of Neuritin 1 (NRN1) polymorphisms on fluid intelligence in schizophrenia. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:428-437. [PMID: 19569075 DOI: 10.1002/ajmg.b.30996] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Neuritin 1 (NRN1), an activity-regulated gene with multiple roles in neurodevelopment and synaptic plasticity, is located within the 6p24-p25 interval on chromosome 6, previously identified as linked to a subtype of schizophrenia (SZ) characterized by pervasive cognitive deficit (CD). We have tested the effect of NRN1 sequence variation on susceptibility to SZ and on general cognitive ability in patients and non-psychiatric control subjects by re-sequencing the coding regions of NRN1 and its flanking sequences, and genotyping 19 single-nucleotide polymorphisms (SNPs) in 336 SZ patients and 172 healthy control individuals. All participants completed comprehensive neurocognitive assessment, including tests estimating premorbid/prior IQ and current IQ. Logistic regression analyses found no significant association for any of the 19 SNPs with SZ or its CD subtype. However, linear regression analysis gave significant association (P = 0.024 and P = 0.027 after correction for multiple testing) for polymorphisms rs1475157 and rs9405890 with current IQ in the patient group. In SZ, the rs1475157-rs9405890 haplotypes revealed a highly significant association with the abstraction component of current ("fluid") intelligence (P = 0.0014), and with percentage loss of IQ points between premorbid and current intelligence (P = 0.0041). Results in the control group were not significant after correction. This is the first analysis of association between variation in NRN1 and SZ. The findings suggest a role of NRN1 as a modifier of cognitive functioning in SZ, with implications for future research into the impact of the environment on the development and maintenance of "fluid" intelligence.
Collapse
Affiliation(s)
- David Chandler
- Centre for Medical Research/Western Australian Institute for Medical Research, The University of Western Australia, Perth, Australia.,Centre for Clinical Research in Neuropsychiatry and School of Psychiatry and Clinical Neurosciences, Graylands Hospital, The University of Western Australia, Perth, Australia
| | - Milan Dragović
- Centre for Clinical Research in Neuropsychiatry and School of Psychiatry and Clinical Neurosciences, Graylands Hospital, The University of Western Australia, Perth, Australia
| | - Matthew Cooper
- Centre for Medical Research/Western Australian Institute for Medical Research, The University of Western Australia, Perth, Australia.,Centre for Genetic Epidemiology and Biostatistics, The University of Western Australia, Perth, Australia
| | - Johanna C Badcock
- Centre for Clinical Research in Neuropsychiatry and School of Psychiatry and Clinical Neurosciences, Graylands Hospital, The University of Western Australia, Perth, Australia
| | - Benjamin H Mullin
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital and School of Medicine and Pharmacology, The University of Western Australia, Perth, Australia
| | - Deb Faulkner
- Centre for Clinical Research in Neuropsychiatry and School of Psychiatry and Clinical Neurosciences, Graylands Hospital, The University of Western Australia, Perth, Australia
| | - Scott G Wilson
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital and School of Medicine and Pharmacology, The University of Western Australia, Perth, Australia
| | - Joachim Hallmayer
- Department of Psychiatry and Behavioural Sciences, Stanford University School of Medicine, Palo Alto, California
| | - Sarah Howell
- Centre for Clinical Research in Neuropsychiatry and School of Psychiatry and Clinical Neurosciences, Graylands Hospital, The University of Western Australia, Perth, Australia
| | - Daniel Rock
- Centre for Clinical Research in Neuropsychiatry and School of Psychiatry and Clinical Neurosciences, Graylands Hospital, The University of Western Australia, Perth, Australia
| | - Lyle J Palmer
- Centre for Genetic Epidemiology and Biostatistics, The University of Western Australia, Perth, Australia
| | - Luba Kalaydjieva
- Centre for Medical Research/Western Australian Institute for Medical Research, The University of Western Australia, Perth, Australia
| | - Assen Jablensky
- Centre for Clinical Research in Neuropsychiatry and School of Psychiatry and Clinical Neurosciences, Graylands Hospital, The University of Western Australia, Perth, Australia
| |
Collapse
|
21
|
Chan KC, Xing K, Cheung MM, Zhou IY, Wu EX. Functional MRI of postnatal visual development in normal rat superior colliculi. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:4436-9. [PMID: 19963832 DOI: 10.1109/iembs.2009.5332756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This study employed blood oxygenation level-dependent functional MRI (BOLD-fMRI) to evaluate the visual responses in the superior colliculus of the developing rat brain from the time of eyelid opening to adulthood. Upon flash illumination to the contralateral eye, the regional BOLD response underwent a systematic increase in amplitude with age especially after the third postnatal week. However, no significant difference in BOLD signal increase was found between postnatal days 14 and 21. Our results constitute the first fMRI report in demonstrating the critical period of visual functions in the rat brain during maturation. This can be potentially useful in establishing the links between changes in relation to visual sensory development.
Collapse
Affiliation(s)
- Kevin C Chan
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China.
| | | | | | | | | |
Collapse
|
22
|
Loebrich S, Nedivi E. The function of activity-regulated genes in the nervous system. Physiol Rev 2009; 89:1079-103. [PMID: 19789377 DOI: 10.1152/physrev.00013.2009] [Citation(s) in RCA: 175] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The mammalian brain is plastic in the sense that it shows a remarkable capacity for change throughout life. The contribution of neuronal activity to brain plasticity was first recognized in relation to critical periods of development, when manipulating the sensory environment was found to profoundly affect neuronal morphology and receptive field properties. Since then, a growing body of evidence has established that brain plasticity extends beyond development and is an inherent feature of adult brain function, spanning multiple domains, from learning and memory to adaptability of primary sensory maps. Here we discuss evolution of the current view that plasticity of the adult brain derives from dynamic tuning of transcriptional control mechanisms at the neuronal level, in response to external and internal stimuli. We then review the identification of "plasticity genes" regulated by changes in the levels of electrical activity, and how elucidating their cellular functions has revealed the intimate role transcriptional regulation plays in fundamental aspects of synaptic transmission and circuit plasticity that occur in the brain on an every day basis.
Collapse
Affiliation(s)
- Sven Loebrich
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | |
Collapse
|
23
|
Functional MRI of postnatal visual development in normal and hypoxic-ischemic-injured superior colliculi. Neuroimage 2009; 49:2013-20. [PMID: 19879366 DOI: 10.1016/j.neuroimage.2009.10.069] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 10/17/2009] [Accepted: 10/23/2009] [Indexed: 11/22/2022] Open
Abstract
The superior colliculus (SC) is a laminated subcortical structure in the mammalian midbrain, whose superficial layers receive visual information from the retina and the visual cortex. To date, its functional organization and development in the visual system remain largely unknown. This study employed blood oxygenation level-dependent (BOLD) functional MRI to evaluate the visual responses of the SC in normally developing and severe neonatal hypoxic-ischemic (HI)-injured rat brains from the time of eyelid opening to adulthood. MRI was performed to the normal animals (n=7) at postnatal days (P) 14, 21, 28 and 60. In the HI-injured group (n=7), the ipsilesional primary and secondary visual cortices were completely damaged after unilateral ligation of the left common carotid artery at P7 followed by hypoxia for 2 h, and MRI was performed at P60. Upon unilateral flash illumination, the normal contralateral SC underwent a systematic increase in BOLD signal amplitude with age especially after the third postnatal week. However, no significant difference in BOLD signal increase was found between P14 and P21. These findings implied the presence of neurovascular coupling at the time of eyelid opening, and the progressive development of hemodynamic regulation in the subcortical visual system. In the HI-injured group at P60, the BOLD signal increases in both SC remained at the same level as the normal group at P28 though they were significantly lower than the normal group at P60. These observations suggested the residual visual functions on both sides of the subcortical brain, despite the damages to the entire ipsilesional visual cortex. The results of this study constitute important evidence on the progressive maturation of visual functions and hemodynamic responses in the normal subcortical brain, and its functional plasticity upon neonatal HI injury.
Collapse
|
24
|
Epileptogenesis alters gene expression pattern in rats subjected to amygdala-dependent emotional learning. Neuroscience 2009; 159:468-82. [DOI: 10.1016/j.neuroscience.2008.12.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 12/11/2008] [Accepted: 12/31/2008] [Indexed: 11/18/2022]
|
25
|
Salami M, Aghanouri Z, Noureddini M, Rashidi A. Early Dark Rearing Influences Spatial Performances in the Radial Arm Maze. JOURNAL OF MEDICAL SCIENCES 2008. [DOI: 10.3923/jms.2008.699.706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
26
|
Fujino T, Wu Z, Lin WC, Phillips MA, Nedivi E. cpg15 and cpg15-2 constitute a family of activity-regulated ligands expressed differentially in the nervous system to promote neurite growth and neuronal survival. J Comp Neurol 2008; 507:1831-45. [PMID: 18265009 DOI: 10.1002/cne.21649] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Many ligands that affect nervous system development are members of gene families that function together to coordinate the assembly of complex neural circuits. cpg15/neuritin encodes an extracellular ligand that promotes neurite growth, neuronal survival, and synaptic maturation. Here we identify cpg15-2 as the only paralogue of cpg15 in the mouse and human genome. Both genes are expressed predominantly in the nervous system, where their expression is regulated by activity. cpg15-2 expression increases by more than twofold in response to kainate-induced seizures and nearly fourfold in the visual cortex in response to 24 hours of light exposure following dark adaptation. cpg15 and cpg15-2 diverge in their spatial and temporal expression profiles. cpg15-2 mRNA is most abundant in the retina and the olfactory bulb, as opposed to the cerebral cortex and the hippocampus for cpg15. In the retina, they differ in their cell-type specificity. cpg15 is expressed in retinal ganglion cells, whereas cpg15-2 is predominantly in bipolar cells. Developmentally, onset of cpg15-2 expression is delayed compared with cpg15 expression. CPG15-2 is glycosylphosphatidylinositol (GPI) anchored to the cell membrane and, like CPG15, can be released in a soluble-secreted form, but with lower efficiency. CPG15 and CPG15-2 were found to form homodimers and heterodimers with each other. In hippocampal explants and dissociated cultures, CPG15 and CPG15-2 promote neurite growth and neuronal survival with similar efficacy. Our findings suggest that CPG15 and CPG15-2 perform similar cellular functions but may play distinct roles in vivo through their cell-type- and tissue-specific transcriptional regulation.
Collapse
Affiliation(s)
- Tadahiro Fujino
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | | | | | |
Collapse
|
27
|
Zheng S, Yin ZQ, Zeng YX. Developmental profile of tissue plasminogen activator in postnatal Long Evans rat visual cortex. Mol Vis 2008; 14:975-82. [PMID: 18523654 PMCID: PMC2405812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Accepted: 04/16/2008] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To investigate the distribution, expression, and activity of tissue plasminogen activator (tPA) in the visual cortex of the Long Evans rat during postnatal development, and to explore the relationship between tPA levels and the critical period of visual cortical plasticity. METHODS Long Evans rats of either sex (n=131) were divided by postnatal age in weeks (PW) into five groups: PW1 (6-8 days, before eye opening, n=19), PW3 (20-22 days, beginning of critical period, n=28), PW5 (34-36 days, later stage of critical period, n=28), PW7 (48-50 days, end of critical period, n=28), and PW14 (95-100 days, adult, n=28). The distribution and expression of tPA was detected using immunofluorescence histochemistry and western blot analysis, respectively. tPA activity in the visual cortex was determined using a chromogenic assay kit. RESULTS tPA-containing cells were mostly located in visual cortex layer II-III and layer IV during postnatal development. In layer II-III the density of tPA-containing cells reached peak at PW 5, and then reduced to minimum at PW14. In layer IV and V-VI, the density of tPA-containing cells reached a maximum at PW3, and then decreased to the minimum at PW14. Western blot analysis indicated that tPA was detected in visual cortex of rats from PW3 onwards with the highest quantity present at PW5. By comparison, the peak in tPA activity occurred slightly earlier at PW3, and then decreased steadily to lower levels at PW14. CONCLUSIONS The critical period of visual cortical plasticity, which occurs in early postnatal life, correlates well with tPA expression in the rat visual cortex. This suggests that the expression of tPA is produced in sufficient amounts to balance the increase of chondroitin sulfate proteoglycan expression, at the same time blocking its function, thus allowing synaptic modification to continue. tPA activity may be one of the factors influencing the duration of the critical period and underlying the heterogeneity of synaptic plasticity between visual cortex layer II-III and layer IV.
Collapse
|
28
|
FARGO KEITHN, ALEXANDER THOMASD, TANZER LISA, POLETTI ANGELO, JONES KATHRYNJ. Androgen regulates neuritin mRNA levels in an in vivo model of steroid-enhanced peripheral nerve regeneration. J Neurotrauma 2008; 25:561-6. [PMID: 18419250 PMCID: PMC9848905 DOI: 10.1089/neu.2007.0466] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Following crush injury to the facial nerve in Syrian hamsters, treatment with androgens enhances axonal regeneration rates and decreases time to recovery. It has been demonstrated in vitro that the ability of androgen to enhance neurite outgrowth in motoneurons is dependent on neuritin-a protein that is involved in the re-establisment of neuronal connectivity following traumatic damage to the central nervous system and that is under the control of several neurotrophic and neuroregenerative factors--and we have hypothesized that neuritin is a mediator of the ability of androgen to increase peripheral nerve regeneration rates in vivo. Testosterone treatment of facial nerve-axotomized hamsters resulted in an approximately 300% increase in neuritin mRNA levels 2 days post-injury. Simultaneous treatment with flutamide, an androgen receptor blocker that is known to prevent androgen enhancement of nerve regeneration, abolished the ability of testosterone to upregulate neuritin mRNA levels. In a corroborative in vitro experiment, the androgen dihydrotestosterone induced an approximately 100% increase in neuritin mRNA levels in motoneuron-neuroblastoma cells transfected with androgen receptors, but not in cells without androgen receptors. These data confirm that neuritin is under the control of androgens, and suggest that neuritin is an important effector of androgen in enhancing peripheral nerve regeneration following injury. Given that neuritin has now been shown to be involved in responses to both central and peripheral injuries, and appears to be a common effector molecule for several neurotrophic and neurotherapeutic agents, understanding the neuritin pathway is an important goal for the clinical management of traumatic nervous system injuries.
Collapse
Affiliation(s)
- KEITH N. FARGO
- Neuroscience Program and Department of Cell Biology, Neurobiology and Anatomy, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois.,Research and Development Service, Hines VA Medical Center, Hines, Illinois
| | | | - LISA TANZER
- Neuroscience Program and Department of Cell Biology, Neurobiology and Anatomy, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - ANGELO POLETTI
- Institute of Endocrinology and Center of Excellence on Neurodegenerative Diseases, University of Milan, Milan, Italy
| | - KATHRYN J. JONES
- Neuroscience Program and Department of Cell Biology, Neurobiology and Anatomy, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois.,Research and Development Service, Hines VA Medical Center, Hines, Illinois
| |
Collapse
|
29
|
Fargo KN, Galbiati M, Foecking EM, Poletti A, Jones KJ. Androgen regulation of axon growth and neurite extension in motoneurons. Horm Behav 2008; 53:716-28. [PMID: 18387610 PMCID: PMC2408920 DOI: 10.1016/j.yhbeh.2008.01.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 01/11/2008] [Accepted: 01/18/2008] [Indexed: 01/10/2023]
Abstract
Androgens act on the CNS to affect motor function through interaction with a widespread distribution of intracellular androgen receptors (AR). This review highlights our work on androgens and process outgrowth in motoneurons, both in vitro and in vivo. The actions of androgens on motoneurons involve the generation of novel neuronal interactions that are mediated by the induction of androgen-dependent neurite or axonal outgrowth. Here, we summarize the experimental evidence for the androgenic regulation of the extension and regeneration of motoneuron neurites in vitro using cultured immortalized motoneurons, and axons in vivo using the hamster facial nerve crush paradigm. We place particular emphasis on the relevance of these effects to SBMA and peripheral nerve injuries.
Collapse
Affiliation(s)
- Keith N Fargo
- Department of Cell Biology, Neurobiology, and Anatomy, Loyola University Chicago, Maywood, Illinois 60153, USA.
| | | | | | | | | |
Collapse
|
30
|
Cappelletti G, Galbiati M, Ronchi C, Maggioni MG, Onesto E, Poletti A. Neuritin (cpg15) enhances the differentiating effect of NGF on neuronal PC12 cells. J Neurosci Res 2008; 85:2702-13. [PMID: 17335086 DOI: 10.1002/jnr.21235] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neuritin is a small, highly conserved GPI-anchored protein involved in neurite outgrowth. We have analyzed the involvement of neuritin in NGF-induced differentiation of PC12 cells by investigating the time-course of neuritin expression, the effects of its overexpression or silencing, and the possible mechanisms of its regulation and action. Real-time PCR analysis has shown that neuritin gene is upregulated by NGF in PC12 cells hours before neurite outgrowth becomes appreciable. PC12 cells transfected with a plasmid expressing neuritin display a significant increase in the response to NGF: 1) in the levels of SMI312 positive phosphorylated neurofilament proteins (markers for axonal processes) and tyrosine hydroxylase; 2) in the percentage of cells bearing neurites; as well as 3) in the average length of neurites when compared to control cells. On the contrary, neuritin silencing significantly reduces neurite outgrowth. These data suggest that neuritin is a modulator of NGF-induced neurite extension in PC12 cells. We also showed that neuritin potentiated the NGF-induced differentiation of PC12 cells without affecting TrkA or EGF receptor mRNAs expression. Moreover, the S-methylisothiourea (MIU), a potent inhibitor of inducible nitric oxide synthases, partially counteracts the NGF-mediated neuritin induction. These data suggest that NGF regulates neuritin expression in PC12 cells via the signaling pathway triggered by NO. This study reports the first evidence that neuritin plays a role in modulating neurite outgrowth during the progression of NGF-induced differentiation of PC12 cells. PC12 cells could be considered a valuable model to unravel the mechanism of action of neuritin on neurite outgrowth. (c) 2007 Wiley-Liss, Inc.
Collapse
|
31
|
Cantallops I, Cline HT. Rapid activity-dependent delivery of the neurotrophic protein CPG15 to the axon surface of neurons in intactXenopus tadpoles. Dev Neurobiol 2008; 68:744-59. [DOI: 10.1002/dneu.20529] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
32
|
Bidirectional regulation of Munc13-3 protein expression by age and dark rearing during the critical period in mouse visual cortex. Neuroscience 2007; 150:603-8. [PMID: 17997229 DOI: 10.1016/j.neuroscience.2007.09.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 09/21/2007] [Accepted: 09/28/2007] [Indexed: 11/24/2022]
Abstract
Rearing in darkness slows the time course of the visual cortical critical period, such that at 5 weeks of age normal cats are more plastic than dark-reared cats, while at 20 weeks dark-reared cats are more plastic [Mower GD (1991) The effect of dark rearing on the time course of the critical period in cat visual cortex. Dev Brain Res 58:151-158]. Thus, genes that are important for visual cortical plasticity should show differences in expression between normal and dark-reared visual cortex that are of opposite direction in young versus older animals. Previously, we showed by differential display polymerase chain reaction and northern blotting that mRNA for Munc13-3, a mammalian homologue of the C. elegans uncoordinated (unc) gene, shows such bidirectional regulation in cat visual cortex [Yang CB, Zheng YT, Li GY, Mower GD (2002) Identification of Munc13-3 as a candidate gene for critical period neuroplasticity in visual cortex. J Neurosci 22:8614-8618]. Here, the analysis is extended to Munc13-3 protein in mouse visual cortex, which will provide the basis for gene manipulation analysis. In mice, Munc13-3 protein was elevated 2.3-fold in dark-reared compared with normal visual cortex at 3.5 weeks and 2.0-fold in normal compared with dark-reared visual cortex at 9.5 weeks. Analysis of variance of protein levels showed a significant interaction, indicating that the effect of dark rearing depended on age. This bidirectional regulation was restricted to visual cortex and did not occur in frontal cortex. Bidirectional regulation was also specific to Munc13-3 and was not found for other Munc13 family members. Munc13 proteins serve a central priming function in synaptic vesicle exocytosis at glutamatergic and GABAergic synapses and this work contributes to the growing evidence indicating a role of Munc13 genes in synaptic plasticity.
Collapse
|
33
|
Schirmer M, Kaiser A, Lessenich A, Lindemann S, Fedrowitz M, Gernert M, Löscher W. Auditory and vestibular defects and behavioral alterations after neonatal administration of streptomycin to Lewis rats: Similarities and differences to the circling (ci2/ci2) Lewis rat mutant. Brain Res 2007; 1155:179-95. [PMID: 17493596 DOI: 10.1016/j.brainres.2007.04.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 04/04/2007] [Accepted: 04/06/2007] [Indexed: 11/28/2022]
Abstract
The clinical usefulness of aminoglycoside antibiotics is limited by their ototoxicity. In rodents, damage to the inner ear is often associated with rotational behavior and locomotor hyperactivity reminiscent of such behaviors resulting from an imbalance of forebrain dopamine systems. Based on previous observations in the circling (ci2/ci2) Lewis (LEW) rat mutant, a spontaneous mutation leading to hair cell loss, deafness, impairment of vestibular functions, lateralized circling, hyperactivity and alterations in the nigrostriatal dopamine system, we have recently hypothesized that vestibular defects during postnatal development, independent of whether induced or inherited, lead to secondary changes in the dopaminergic system within the basal ganglia, which would be a likely explanation for the typical behavioral phenotype seen in such models. In the present study, we directly compared the phenotype induced by streptomycin in LEW rats with that of the ci2 LEW rat mutant. For this purpose, we treated neonatal LEW rats over 3 weeks by streptomycin, which induced bilateral degeneration of cochlear and vestibular hair cells. Following this treatment period, the behavioral syndrome of the streptomycin-treated animals, including the lateralized rotational behavior, was almost indistinguishable from that of ci2 mutant rats. However, in contrast to the ci2 mutant rat, all alterations, except the hearing loss, were only transient, disappearing between 7 and 24 weeks following treatment. In conclusion, in line with our hypothesis, vestibular defects induced in normal LEW rats led to the same phenotypic behavior as the inherited vestibular defect of ci2 mutant rats. However, with increasing time for recovery, adaptation to the vestibular impairment developed in streptomycin-treated rats, while all deficits persisted in the mutant animals. At least in part, the transient nature of the abnormal behaviors resulting from treatment with streptomycin could be explained by adaptation to the vestibular impairment by the use of visual cues, which is not possible in ci2 rats because of progressive retinal degeneration in these mutants. Although further experiments are needed to prove this hypothesis, the present study shows that direct comparisons between these two models serve to understand the mechanisms underlying the complex behavioral phenotype in rodents with vestibular defects and how these defects are compensated.
Collapse
Affiliation(s)
- Marko Schirmer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, Hannover, Germany
| | | | | | | | | | | | | |
Collapse
|
34
|
Han Y, Chen X, Shi F, Li S, Huang J, Xie M, Hu L, Hoidal JR, Xu P. CPG15, A New Factor Upregulated after Ischemic Brain Injury, Contributes to Neuronal Network Re-Establishment after Glutamate-Induced Injury. J Neurotrauma 2007; 24:722-31. [PMID: 17439354 DOI: 10.1089/neu.2006.0174] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Candidate plasticity-related gene 15 (cpg15) encodes a protein that regulates dendritic and axonal arbor growth and synaptic maturation. In the present study, we investigated the potential role of CPG15 in regulating the neuronal network re-establishment after ischemic brain injury. In the mouse model with transient global ischemia (TGI), CPG15 transcripts and proteins were determined using RT-PCR and Western blot analyses. Cell proliferation was observed using 5'-bromo-2'-deoxyuridine-5'-monophosphate (BrdU) labeling. Double immunostaining and depletion of soluble CPG15 proteins were performed to examine the cellular distribution of CPG15 and the role of soluble CPG15 in the neurite outgrowth during the neuronal network re-establishment in primarily cultured hippocampal cells after glutamate-induced injury. We demonstrated that CPG15 expression in the hippocampus was upregulated at 1-2 weeks after TGI. In the dentate gyrus, the number of CPG15 and BrdU positive cells increased concurrently after the injury. During the neuronal network re-establishment after the glutamate-induced injury of primarily cultured hippocampal cells, CPG15 was mainly located at the ends and turn-off regions of the growth cones and in the vesicles. Depletion of soluble CPG15 proteins secreted from the hippocampal cells in the culture media significantly reduced the neurite outgrowth and neuron-neuron connection. The results indicate that CPG15 may function as a new factor required in re-establishment of neuronal network after the injury. Our findings will be important in developing a new strategy to enhance endogenous neurogenesis after an ischemic brain injury.
Collapse
Affiliation(s)
- Yu Han
- State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Rickhag M, Teilum M, Wieloch T. Rapid and long-term induction of effector immediate early genes (BDNF, Neuritin and Arc) in peri-infarct cortex and dentate gyrus after ischemic injury in rat brain. Brain Res 2007; 1151:203-10. [PMID: 17397810 DOI: 10.1016/j.brainres.2007.03.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 03/01/2007] [Accepted: 03/02/2007] [Indexed: 01/30/2023]
Abstract
The genomic response following brain ischemia is very complex and involves activation of both protective and detrimental signaling pathways. Immediate early genes (IEGs) represent the first wave of gene expression following ischemia and are induced in extensive regions of the ischemic brain including cerebral cortex and hippocampus. Brain-derived neurotrophic factor (BDNF), Neuritin and Activity-regulated cytoskeleton-associated protein (Arc) belong to a subgroup of immediate early genes implicated in synaptic plasticity known as effector immediate early genes. Here, we investigated the spatial and temporal activation pattern for these genes during the first 24 h of reperfusion following 2-h occlusion of the middle cerebral artery. Neuritin showed a persistent activation in frontal-cingulate cortex while Arc displayed a biphasic response. Also, in dentate gyrus, activation was observed at 0-6 h of reperfusion for Neuritin and 0-12 h of reperfusion for Arc while BDNF was induced 0-9 h of reperfusion. Our study demonstrates a rapid and long-term activation of effector immediate early genes in distinct brain areas following ischemic injury in rat. Effector gene activation may be part of long-term synaptic responses of ischemic brain tissue.
Collapse
Affiliation(s)
- Mattias Rickhag
- Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, University of Lund, BMC A13, 22184 Lund, Sweden.
| | | | | |
Collapse
|
36
|
Carrasco MM, Pallas SL. Early visual experience prevents but cannot reverse
deprivation-induced loss of refinement in adult superior colliculus. Vis Neurosci 2007; 23:845-52. [PMID: 17266776 DOI: 10.1017/s0952523806230177] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Accepted: 07/24/2006] [Indexed: 11/05/2022]
Abstract
The role of sensory experience in the development and plasticity of
the visual system has been widely studied. It has generally been reported
that once animals reach adulthood, experience-dependent visual plasticity
is reduced. We have found that visual experience is not needed for the
refinement of receptive fields (RFs) in the superior colliculus (SC) but
instead is necessary to maintain them in adulthood (Carrasco et al., 2005). Without light exposure, RFs in SC of hamsters
refine by postnatal day 60 as usual but then enlarge, presumably reducing
visual acuity. In this study we examine whether a brief period of light
exposure during early postnatal development would be sufficient to prevent
RF enlargement in adulthood, and whether prolonged light exposure in
adulthood could reverse the deprivation-induced increase in RF size. We
found that an early postnatal period of at least 30 days of visual
experience was sufficient to maintain refined RFs in the adult SC.
Prolonged visual experience in adulthood could not reverse the RF
enlargement resulting from long-term dark rearing, reflecting a loss of
plasticity at this age. Our results suggest that, unlike in visual cortex,
dark rearing does not indefinitely extend the critical period of
plasticity in SC. Rather, there is a limited time window when early
experience can protect RFs from the detrimental effects of visual
deprivation in adulthood. These results contribute to understanding adult
brain plasticity and argue for the importance of early visual experience
in protecting the adult visual system.
Collapse
Affiliation(s)
- María Magdalena Carrasco
- Graduate Program in Neurobiology and Behavior, Department of Biology, Georgia State University, Atlanta, Georgia 30303, USA
| | | |
Collapse
|
37
|
Latefi NS, Colman DR. The CNS synapse revisited: gaps, adhesive welds, and borders. Neurochem Res 2006; 32:303-10. [PMID: 17080313 DOI: 10.1007/s11064-006-9181-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Accepted: 09/22/2006] [Indexed: 12/16/2022]
Abstract
Although processes leading up to the point of synapse formation are fairly well understood, the precise sequence of events in which the membranes of two separate cells "lock in" to form a mature synaptic junctional complex is poorly understood. A careful study of the molecules operating at the synapse indicates that their roles are more multifarious than once imagined. In this review we posit that the synapse is a functional organelle with poorly defined boundaries and a complex biochemistry. The role of adhesion molecules, including the integration of their signaling and adhesive properties in the context of synaptic activity is discussed.
Collapse
Affiliation(s)
- Nazlie S Latefi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, BT-105, H3A2B4, Montreal, QC, Canada.
| | | |
Collapse
|
38
|
Yang CB, Zheng YT, Kiser PJ, Mower GD. Identification of disabled-1 as a candidate gene for critical period neuroplasticity in cat and mouse visual cortex. Eur J Neurosci 2006; 23:2804-8. [PMID: 16817883 DOI: 10.1111/j.1460-9568.2006.04799.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rearing in darkness slows the time course of the critical period in visual cortex, such that at 5 weeks of age normal cats are more plastic than dark-reared cats, whereas at 20 weeks dark-reared cats are more plastic [G. D. Mower (1991)Dev. Brain Res., 58, 151-158]. Thus, a stringent criterion is that genes that are important for plasticity in visual cortex will show differences in expression between normal and dark-reared visual cortex that are of opposite direction in young vs. older animals. The present study reports the identification by differential display PCR of Dab-1, the mammalian homolog of the drosophila disabled-1 gene, as a candidate gene for critical period neuronal plasticity, expression of which is regulated according to this criterion in cat visual cortex. Evidence for this bidirectional direction regulation is extended to Dab-1 protein in cat and mouse visual cortex and shown to be specific to visual cortex, not occurring in frontal cortex. The Reelin/Dab-1 pathway has well-documented functions in cell migration during prenatal life and increasing evidence indicates that in postnatal brain the pathway plays a role in synaptic plasticity. The present results extend this evidence by directly implicating Dab-1 in postnatal critical period plasticity of visual cortex.
Collapse
Affiliation(s)
- Cui Bo Yang
- Department of Anatomical Sciences and Neurobiology, University of Louisville, KY 40202, USA
| | | | | | | |
Collapse
|
39
|
Moreno-López B, González-Forero D. Nitric Oxide and Synaptic Dynamics in the Adult Brain: Physiopathological Aspects. Rev Neurosci 2006; 17:309-57. [PMID: 16878402 DOI: 10.1515/revneuro.2006.17.3.309] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The adult brain retains the capacity to rewire mature neural circuits in response to environmental changes, brain damage or sensory and motor experiences. Two plastic processes, synaptic remodeling and neurogenesis, have been the subject of numerous studies due to their involvement in the maturation of the nervous system, their prevalence and re-activation in adulthood, and therapeutic relevance. However, most of the research looking for the mechanistic and molecular events underlying synaptogenic phenomena has been focused on the extensive synaptic reorganization occurring in the developing brain. In this stage, a vast number of synapses are initially established, which subsequently undergo a process of activity-dependent refinement guided by target-derived signals that act as synaptotoxins or synaptotrophins, promoting either loss or consolidation of pre-existing synaptic contacts, respectively. Nitric oxide (NO), an autocrine and/or paracrine-acting gaseous molecule synthesized in an activity-dependent manner, has ambivalent actions. It can act by mediating synapse formation, segregation of afferent inputs, or growth cone collapse and retraction in immature neural systems. Nevertheless, little information exists about the role of this ambiguous molecule in synaptic plasticity processes occurring in the adult brain. Suitable conditions for elucidating the role of NO in adult synaptic rearrangement include physiopathological conditions, such as peripheral nerve injury. We have recently developed a crush lesion model of the XIIth nerve that induces a pronounced stripping of excitatory synaptic boutons from the cell bodies of hypoglossal motoneurons. The decline in synaptic coverage was concomitant with de novo expression of the neuronal isoform of NO synthase in motoneurons. We have demonstrated a synaptotoxic action of NO mediating synaptic withdrawal and preventing synapse formation by cyclic GMP (cGMP)-dependent and, probably, S-nitrosylation-mediated mechanisms, respectively. This action possibly involves the participation of other signaling molecules working together with NO. Brain-derived neurotrophic factor (BDNF), a target-derived synaptotrophin synthesized and released postsynaptically in an activity-dependent form, is a potential candidate for effecting such a concerted action. Several items of evidence support an interrelationship between NO and BDNF in the regulation of synaptic remodeling processes in adulthood: i) BDNF and its receptor TrkB are expressed by motoneurons and upregulated by axonal injury; ii) they promote axon arborization and synaptic formation, and modulate the structural dynamics of excitatory synapses; iii) NO and BDNF each control the production and activity of the other at the level of individual synapses; iv) the NO/cGMP pathway inhibits BDNF secretion; and finally, v) BDNF protects F-actin from depolymerization by NO, thus preventing the collapsing and retracting effects of NO on growth cones. Therefore, we propose a mechanism of action in which the NO/BDNF ratio regulates synapse dynamics after peripheral nerve lesion. This hypothesis also raises the possibility that variations in this NO/BDNF balance constitute a common hallmark leading to synapse loss in the progression of diverse neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's and Parkinson's diseases.
Collapse
|
40
|
Lee WCA, Huang H, Feng G, Sanes JR, Brown EN, So PT, Nedivi E. Dynamic remodeling of dendritic arbors in GABAergic interneurons of adult visual cortex. PLoS Biol 2005; 4:e29. [PMID: 16366735 PMCID: PMC1318477 DOI: 10.1371/journal.pbio.0040029] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 11/22/2005] [Indexed: 12/03/2022] Open
Abstract
Despite decades of evidence for functional plasticity in the adult brain, the role of structural plasticity in its manifestation remains unclear. To examine the extent of neuronal remodeling that occurs in the brain on a day-to-day basis, we used a multiphoton-based microscopy system for chronic in vivo imaging and reconstruction of entire neurons in the superficial layers of the rodent cerebral cortex. Here we show the first unambiguous evidence (to our knowledge) of dendrite growth and remodeling in adult neurons. Over a period of months, neurons could be seen extending and retracting existing branches, and in rare cases adding new branch tips. Neurons exhibiting dynamic arbor rearrangements were GABA-positive non-pyramidal interneurons, while pyramidal cells remained stable. These results are consistent with the idea that dendritic structural remodeling is a substrate for adult plasticity and they suggest that circuit rearrangement in the adult cortex is restricted by cell type–specific rules. Chronic in vivo imaging of fluorescent-labeled neurons in adult mice reveals extension and retraction of dendrites in GABAergic non-pyramidal interneurons of the cerebral cortex.
Collapse
Affiliation(s)
- Wei-Chung Allen Lee
- 1The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- 2Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Hayden Huang
- 3Department of Mechanical Engineering and Division of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Guoping Feng
- 4Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joshua R Sanes
- 5Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Emery N Brown
- 2Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- 6MIT-Harvard Division of Health Science and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- 7Neuroscience Statistics Research Laboratory, Department of Anaesthesia and Critical Care, Massachusetts General Hospital, Boston, United States of America
| | - Peter T So
- 3Department of Mechanical Engineering and Division of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Elly Nedivi
- 1The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- 2Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- 8Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
41
|
Harwell C, Burbach B, Svoboda K, Nedivi E. Regulation of cpg15 expression during single whisker experience in the barrel cortex of adult mice. ACTA ACUST UNITED AC 2005; 65:85-96. [PMID: 16010668 PMCID: PMC3062911 DOI: 10.1002/neu.20176] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Regulation of gene transcription by neuronal activity is thought to be key to the translation of sensory experience into long-term changes in synaptic structure and function. Here we show that cpg15, a gene encoding an extracellular signaling molecule that promotes dendritic and axonal growth and synaptic maturation, is regulated in the somatosensory cortex by sensory experience capable of inducing cortical plasticity. Using in situ hybridization, we monitored cpg15 expression in 4-week-old mouse barrel cortex after trimming all whiskers except D1. We found that cpg15 expression is depressed in the deprived barrels and enhanced in the barrel column corresponding to the spared D1 whisker. Changes in cpg15 mRNA levels first appear in layer IV, peak 12 h after deprivation, and then decline rapidly. In layers II/III, changes in cpg15 expression appear later, peak at 24 h, and persist for days. Induction of cpg15 expression is significantly diminished in adolescent as well as adult CREB knockout mice. cpg15's spatio-temporal expression pattern and its regulation by CREB are consistent with a role in experience-dependent plasticity of cortical circuits. Our results suggest that local structural and/or synaptic changes may be a mechanism by which the adult cortex can adapt to peripheral manipulations.
Collapse
Affiliation(s)
- Corey Harwell
- The Picower Center for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 50 Ames Street, E18-670, Cambridge, Massachusetts 02139, USA
| | | | | | | |
Collapse
|
42
|
Carrasco MM, Razak KA, Pallas SL. Visual Experience Is Necessary for Maintenance But Not Development of Receptive Fields in Superior Colliculus. J Neurophysiol 2005; 94:1962-70. [PMID: 15917326 DOI: 10.1152/jn.00166.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sensory deprivation is thought to have an adverse effect on visual development and to prolong the critical period for plasticity. Once the animal reaches adulthood, however, synaptic connectivity is understood to be largely stable. We reported previously that N-methyl-d-aspartate (NMDA) receptor blockade in the superior colliculus of the Syrian hamster prevents refinement of receptive fields (RFs) in normal or compressed retinotopic projections, resulting in target neurons with enlarged RFs but normal stimulus tuning. Here we asked whether visually driven activity is necessary for refinement or maintenance of retinotopic maps or if spontaneous activity is sufficient. Animals were deprived of light either in adulthood only or from birth until the time of recording. We found that dark rearing from birth to 2 mo of age had no effect on the timing and extent of RF refinement as assessed with single unit extracellular recordings. Visual deprivation in adulthood also had no effect. Continuous dark rearing from birth into adulthood, however, resulted in a progressive loss of refinement, resulting in enlarged, asymmetric receptive fields and altered surround suppression in adulthood. Thus unlike in visual cortex, early visually driven activity is not necessary for refinement of receptive fields during development, but is required to maintain refined visual projections in adulthood. Because the map can refine normally in the dark, these results argue against a deprivation-induced delay in critical period closure, and suggest instead that early visual deprivation leaves target neurons more vulnerable to deprivation that continues after refinement.
Collapse
Affiliation(s)
- M M Carrasco
- Graduate Program in Neurobiology and Behavior, Department of Biology, Georgia State University, 24 Peachtree Center Ave., Atlanta, Georgia 30303, USA
| | | | | |
Collapse
|
43
|
Putz U, Harwell C, Nedivi E. Soluble CPG15 expressed during early development rescues cortical progenitors from apoptosis. Nat Neurosci 2005; 8:322-31. [PMID: 15711540 PMCID: PMC3075944 DOI: 10.1038/nn1407] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Accepted: 01/21/2005] [Indexed: 12/31/2022]
Abstract
The balance between proliferation and apoptosis is critical for proper development of the nervous system. Yet, little is known about molecules that regulate apoptosis of proliferative neurons. Here we identify a soluble, secreted form of CPG15 expressed in embryonic rat brain regions undergoing rapid proliferation and apoptosis, and show that it protects cultured cortical neurons from apoptosis by preventing activation of caspase 3. Using a lentivirus-delivered small hairpin RNA, we demonstrate that endogenous CPG15 is essential for the survival of undifferentiated cortical progenitors in vitro and in vivo. We further show that CPG15 overexpression in vivo expands the progenitor pool by preventing apoptosis, resulting in an enlarged, indented cortical plate and cellular heterotopias within the ventricular zone, similar to the phenotypes of mutant mice with supernumerary forebrain progenitors. CPG15 expressed during mammalian forebrain morphogenesis may help balance neuronal number by countering apoptosis in specific neuroblasts subpopulations, thus influencing final brain size and shape.
Collapse
Affiliation(s)
- Ulrich Putz
- The Picower Center for Learning and Memory, Departments of Brain and Cognitive Sciences and Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | |
Collapse
|
44
|
Marron TU, Guerini V, Rusmini P, Sau D, Brevini TAL, Martini L, Poletti A. Androgen-induced neurite outgrowth is mediated by neuritin in motor neurones. J Neurochem 2005; 92:10-20. [PMID: 15606892 DOI: 10.1111/j.1471-4159.2004.02836.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In the brain, the spinal cord motor neurones express the highest levels of the androgen receptor (AR). Experimental data have suggested that neurite outgrowth in these neurones may be regulated by testosterone or its derivative 5alpha-dihydrotestosterone (DHT), formed by the 5alpha-reductase type 2 enzyme. In this study we have produced and characterized a model of immortalized motor neuronal cells expressing the mouse AR (mAR) [neuroblastoma-spinal cord (NSC) 34/mAR] and analysed the role of androgens in motor neurones. Androgens either activated or repressed several genes; one has been identified as the mouse neuritin, a protein responsible for neurite elongation. Real-time PCR analysis has shown that the neuritin gene is expressed in the basal condition in immortalized motor neurones and is selectively up-regulated by androgens in NSC34/mAR cells; the DHT effect is counteracted by the anti-androgen Casodex. Moreover, DHT induced neurite outgrowth in NSC34/mAR, while testosterone was less effective and its action was counteracted by the 5alpha-reductase type 2 enzyme inhibitor finasteride. Finally, the androgenic effect on neurite outgrowth was abolished by silencing neuritin with siRNA. Therefore, the trophic effects of androgens in motor neurones may be explained by the androgenic regulation of neuritin, a protein linked to neurone development, elongation and regeneration.
Collapse
Affiliation(s)
- T U Marron
- Institute of Endocrinology, Center of Excellence on Neurodegenerative Diseases, University of Milan, Milan, Italy
| | | | | | | | | | | | | |
Collapse
|
45
|
Cottrell JR, Borok E, Horvath TL, Nedivi E. CPG2: a brain- and synapse-specific protein that regulates the endocytosis of glutamate receptors. Neuron 2005; 44:677-90. [PMID: 15541315 PMCID: PMC3065105 DOI: 10.1016/j.neuron.2004.10.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Revised: 08/05/2004] [Accepted: 10/13/2004] [Indexed: 01/20/2023]
Abstract
Long-term maintenance and modification of synaptic strength involve the turnover of neurotransmitter receptors. Glutamate receptors are constitutively and acutely internalized, presumptively through clathrin-mediated receptor endocytosis. Here, we show that cpg2 is a brain-specific splice variant of the syne-1 gene that encodes a protein specifically localized to a postsynaptic endocytotic zone of excitatory synapses. RNAi-mediated CPG2 knockdown increases the number of postsynaptic clathrin-coated vesicles, some of which traffic NMDA receptors, disrupts the constitutive internalization of glutamate receptors, and inhibits the activity-induced internalization of synaptic AMPA receptors. Manipulating CPG2 levels also affects dendritic spine size, further supporting a function in regulating membrane transport. Our results suggest that CPG2 is a key component of a specialized postsynaptic endocytic mechanism devoted to the internalization of synaptic proteins, including glutamate receptors. The activity dependence and distribution of cpg2 expression further suggest that it contributes to the capacity for postsynaptic plasticity inherent to excitatory synapses.
Collapse
Affiliation(s)
- Jeffrey R. Cottrell
- The Picower Center for Learning and Memory Department of Brain and Cognitive Sciences
| | - Erzsebet Borok
- Department of Obstetrics/Gynecology and Reproductive Sciences
| | - Tamas L. Horvath
- Department of Obstetrics/Gynecology and Reproductive Sciences
- Department of Neurobiology Yale University Medical School New Haven, Connecticut 06520
| | - Elly Nedivi
- The Picower Center for Learning and Memory Department of Brain and Cognitive Sciences
- Department of Biology Massachusetts Institute of Technology Cambridge, Massachusetts 02139
- Correspondence:
| |
Collapse
|
46
|
Di Giovanni S, Faden AI, Yakovlev A, Duke-Cohan JS, Finn T, Thouin M, Knoblach S, De Biase A, Bregman BS, Hoffman EP. Neuronal plasticity after spinal cord injury: identification of a gene cluster driving neurite outgrowth. FASEB J 2004; 19:153-4. [PMID: 15522907 DOI: 10.1096/fj.04-2694fje] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Functional recovery after spinal cord injury (SCI) may result in part from axon outgrowth and related plasticity through coordinated changes at the molecular level. We employed microarray analysis to identify a subset of genes the expression patterns of which were temporally coregulated and correlated to functional recovery after SCI. Steady-state mRNA levels of this synchronously regulated gene cluster were depressed in both ventral and dorsal horn neurons within 24 h after injury, followed by strong re-induction during the following 2 wk, which paralleled functional recovery. The identified cluster includes neuritin, attractin, microtubule-associated protein 1a, and myelin oligodendrocyte protein genes. Transcriptional and protein regulation of this novel gene cluster was also evaluated in spinal cord tissue and in single neurons and was shown to play a role in axonal plasticity. Finally, in vitro transfection experiments in primary dorsal root ganglion cells showed that cluster members act synergistically to drive neurite outgrowth.
Collapse
Affiliation(s)
- Simone Di Giovanni
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Ossipow V, Pellissier F, Schaad O, Ballivet M. Gene expression analysis of the critical period in the visual cortex. Mol Cell Neurosci 2004; 27:70-83. [PMID: 15345244 DOI: 10.1016/j.mcn.2004.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2004] [Revised: 05/19/2004] [Accepted: 05/21/2004] [Indexed: 11/24/2022] Open
Abstract
The development of the primary visual cortex in animals possessing binocular vision is a classical paradigm for the study of activity-dependent neuronal plasticity. To elucidate the genetic determinants of this period of substantial plasticity, we conducted an unbiased and comprehensive transcript profiling analysis with differential display and DNA array techniques. We characterized the transcripts that change significantly between the critical and postcritical periods in the rat binocular visual cortex. We determined if these changes are specific for the visual cortex by simultaneously profiling the hippocampus and examined the impact of sensory experience on the accumulation of the identified transcripts. Our results uncover visual cortex-specific and unspecific transcription programs. Transcripts for protein kinases and phosphatases are particularly regulated. The identified transcripts support the notion that the critical period provides a permissive state for plasticity.
Collapse
Affiliation(s)
- Vincent Ossipow
- Department of Biochemistry, University of Geneva, Sciences II, 1211 Geneva 4, Switzerland.
| | | | | | | |
Collapse
|
48
|
Fujino T, Lee WCA, Nedivi E. Regulation of cpg15 by signaling pathways that mediate synaptic plasticity. Mol Cell Neurosci 2003; 24:538-54. [PMID: 14664806 PMCID: PMC3065975 DOI: 10.1016/s1044-7431(03)00230-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Transcriptional activation is a key link between neuronal activity and long-term synaptic plasticity. Little is known about genes responding to this activation whose products directly effect functional and structural changes at the synapse. cpg15 is an activity-regulated gene encoding a membrane-bound ligand that regulates dendritic and axonal arbor growth and synaptic maturation. We report that cpg15 is an immediate-early gene induced by Ca(2+) influx through NMDA receptors and L-type voltage-sensitive calcium channels. Activity-dependent cpg15 expression requires convergent activation of the CaM kinase and MAP kinase pathways. Although activation of PKA is not required for activity-dependent expression, cpg15 is induced by cAMP in active neurons. CREB binds the cpg15 promoter in vivo and partially regulates its activity-dependent expression. cpg15 is an effector gene that is a target for signal transduction pathways that mediate synaptic plasticity and thus may take part in an activity-regulated transcriptional program that directs long-term changes in synaptic connections.
Collapse
Affiliation(s)
- Tadahiro Fujino
- The Picower Center for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | |
Collapse
|
49
|
Demas J, Eglen SJ, Wong ROL. Developmental loss of synchronous spontaneous activity in the mouse retina is independent of visual experience. J Neurosci 2003; 23:2851-60. [PMID: 12684472 PMCID: PMC6742078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
In the immature retina, correlated spontaneous activity in the form of propagating waves is thought to be necessary for the refinement of connections between the retina and its targets. The continued presence of this activity in the mature retina would interfere with the transmission of information about the visual scene. The mechanisms responsible for the disappearance of retinal waves are not well understood, but one hypothesis is that visual experience is important. To test this hypothesis, we monitored the developmental changes in spontaneous retinal activity of both normal mice and mice reared in the dark. Using multi-electrode array recordings, we found that retinal waves in normally reared mice are present at postnatal day (P) 9 and begin to break down shortly after eye opening, around P15. By P21, waves have disappeared, and synchronous firing is comparable with that observed in the adult (6 weeks). In mice raised in the dark, we found a similar time course for the disappearance of waves. However, at P15, dark-reared retinas occasionally showed abnormally long periods of relative inactivity, not seen in controls. Apart from this quiescence, we found no striking differences between the patterns of spontaneous retinal activity from normal and dark-reared mice. We therefore suggest that visual experience is not required for the loss of synchronous spontaneous activity.
Collapse
Affiliation(s)
- Jay Demas
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | |
Collapse
|
50
|
Heinrich JE, Singh TD, Nordeen KW, Nordeen EJ. NR2B downregulation in a forebrain region required for avian vocal learning is not sufficient to close the sensitive period for song learning. Neurobiol Learn Mem 2003; 79:99-108. [PMID: 12482684 DOI: 10.1016/s1074-7427(02)00016-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neural changes that limit the sensitive period for avian song development are unknown, but neurons in a forebrain region critical for song learning, the lMAN, exhibit experience-driven changes in NMDAR subunit expression that could regulate sensitive period closure. Specifically, NR2B levels in lMAN decrease during song acquisition, potentially reducing synaptic plasticity by decreasing NMDAR EPSC duration and/or affecting NMDAR-coupled intracellular cascades. While rearing birds in isolation extends the sensitive period and also delays the developmental changes in NR2B expression and NMDAR physiology, recent work indicates that a transition to faster NMDAR currents does not preclude further song learning. However, NR2B mRNA expression in isolates remains elevated beyond the age at which NMDAR currents shorten, leaving open the possibility that NR2B levels regulate closure of the sensitive period through effects other than those mediated by NMDAR current duration. To determine whether the experience-driven decrease in NR2B expression in lMAN closes the sensitive period, we promoted this change in gene expression either by treating isolation-reared zebra finches briefly with testosterone (T-isolates) or by allowing males limited access to conspecific song (pre-exposed isolates). We then assessed if these birds could acquire song from tutors after the normal close of the sensitive period. Despite a normal decline in NR2B expression, T-isolate and pre-exposed isolate birds learned tutor songs heard from d65-90, while normally reared birds did not. These findings suggest that the normal decline in NR2B expression with lMAN is not sufficient for sensitive period closure.
Collapse
Affiliation(s)
- J E Heinrich
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14627, USA
| | | | | | | |
Collapse
|